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7,381,681 | https://en.wikipedia.org/wiki/List%20of%20psychotropic%20medications | This is a list of psychotropic medications that are currently being marketed.
A
Abilify (aripiprazole) β atypical antipsychotic used to treat schizophrenia, bipolar disorder, and irritability associated with autism
Adderall (mixed amphetamine salts) β a stimulant used to treat ADHD
Ambien (zolpidem) β nonbenzodiazepine used as a sleep aid
Anafranil (clomipramine) β a tricyclic antidepressant; mostly used to treat OCD
Antabuse (disulfiram) β inhibits the enzyme acetaldehyde dehydrogenase, causing acetaldehyde poisoning when ethanol is consumed; used to cause severe hangover when drinking; increases liver, kidney, and brain damage from drinking
Aponal, Quitaxon, Sinequan (doxepin) β a tricyclic antidepressant used to treat nerve pain, insomnia; similar to imipramine
Anquil (benperidol) β an antipsychotic primarily used to control antisocial hypersexual behaviour
Aricept (donepezil) β used to slow the progression of Alzheimer's disease
Ativan (lorazepam) β a benzodiazepine, used to treat anxiety
Asendin (amoxapine) β an dibenzoxazepine antidepressant
Azstarys (Serdexmethylphenidate/Dexmethylphenidate) - a long-acting CNS stimulant used to treat ADHD
B
Buspar (buspirone) β an anxiolytic used to treat generalized anxiety disorder
Belbuca, Buprenex, Butrans, Subutex, Probuohine (buprenorphine) - an opioid medicine used to treat moderate to severe pain, and in some formulations to treat opioid use disorder
Belsomra (Suvorexant) β used to treat insomnia
C
Celexa (citalopram) β an antidepressant of the SSRI class
Centrax (prazepam) β an anti-anxiety agent
Clozaril (clozapine) β atypical antipsychotic used to treat resistant schizophrenia
Concerta (methylphenidate) β an extended release form of methylphenidate
Contrave (naltrexone/bupropion) β a combination drug used in the treatment of mood and psychotic disorders. It is also approved for weight loss in those that are either obese or overweight with some weight-related illnesses
Cymbalta (duloxetine) β an antidepressant of the serotonin-norepinephrine reuptake inhibitors class
D
Depakote (valproic acid/sodium valproate) β an antiepileptic and mood stabilizer used to treat bipolar disorder, neuropathic pain and others; sometimes called an antimanic medication. Depakene is the trade name for the same drug prepared without sodium.
Desyrel (trazodone) β an atypical antidepressant used to treat depression and insomnia
Desoxyn (methamphetamine hydrochloride) β used to treat attention deficit hyperactivity disorder and exogenous obesity
Dexedrine (dextroamphetamine sulfate) β used to treat attention deficit hyperactivity disorder and narcolepsy
E
Effexor and Effexor XR (venlafaxine) β an antidepressant of the SNRI class
Elavil (amitriptyline) β a tricyclic antidepressant used as a first-line treatment for neuropathic pain
Eurodin, Prosom (estazolam) β a benzodiazepine derivative with anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties, commonly prescribed for short-term treatment of insomnia
F
Fetzima (levomilnacipran) β an antidepressant of the SNRI class
Frisium, Onfi, Tapclob, Urbanol (clobazam) β a benzodiazepine that has been marketed as an anxiolytic since 1975 and as an anticonvulsant since 1984
Fycompa (perampanel) β an anti-epileptic medication which can cause serious psychiatric and behavioral changes
G
Geodon (ziprasidone) β atypical antipsychotic used to treat schizophrenia and bipolar mania
Gabitril (tiagabine) β used off-label in the treatment of anxiety disorders and panic disorder
H
Haldol (haloperidol) β typical antipsychotic
I
Imovane (zopiclone) β a non-benzodiazepine hypnotic
Inderal (propranolol) β a beta blocker; it is used for acute anxiety, panic attacks, and hypertension
Intuniv (Guanfacine) - an extended release, non-stimulant alpha-2 adrenergic agonist used to treat attention deficit hyperactivity disorder. Available in instant-release under the brand-name Tenex.
Invega (paliperidone) β atypical antipsychotic used to treat schizophrenia and schizoaffective disorder
K
Keppra (levetiracetam) β an anticonvulsant drug which is sometimes used as a mood stabilizer and has potential benefits for other psychiatric and neurologic conditions such as Tourette syndrome, anxiety disorder, and Alzheimer's disease
Klonopin (clonazepam) β anti-anxiety and anti-epileptic medication of the benzodiazepine class
L
Lamictal (lamotrigine) β an anticonvulsant used as a mood stabilizer
Latuda (lurasidone) β an atypical antipsychotic
Lexapro (escitalopram) β an antidepressant of the SSRI class
Librium (chlordiazepoxide) β a benzodiazepine used to treat acute alcohol withdrawal
Lithobid, Eskalith (lithium) β a mood stabilizer
Loxam (escitalopram) β an antidepressant of the SSRI class
Lunesta (eszopiclone) β a non-benzodiazepine hypnotic
Luvox (fluvoxamine) β an antidepressant of the SSRI class
Loxitane (loxapine) β an antipsychotic used in the treatment of mood disorders and schizophrenia
Lyrica (pregabalin) β treats nerve and muscle pain, including fibromyalgia. It can also treat seizures.
M
Melatonin β a hypnotic used to treat insomnia
Minipress (prazosin) β atypical psychotropic used to treat PTSD
Memantine (Namenda) - treats Dementia and Alzheimer's.
N
Neurontin (gabapentin) β an anticonvulsant which is sometimes used as a mood stabilizer, anti-anxiety agent or to treat chronic pain, particularly diabetic neuropathy
Norapramin (desipramine) β an antidepressant, also used in the treatment of nerve pain
Nuplazid (pimavanserin) β an antipsychotic used to treat hallucinations and delusions caused by psychosis related to Parkinson's disease
P
Pamelor (nortryptiline) β a tricyclic antidepressant
Parnate (tranylcypromine) - a monoamine oxidase inhibitor (MAOI) used in the treatment of depression
Paxil (paroxetine) β an antidepressant of the SSRI class
Nardil (Phenelzine) β an antidepressant of the MAOI class used to treat depression
Orap (Pimozide) β a typical antipsychotic used to treat tic disorder
Pristiq (desvenlafaxine) β an antidepressant of the SNRI class
Prolixin (fluphenazine) β typical antipsychotic
Provigil (modafinil) - used to treat excessive sleepiness and narcolepsy
Prozac (fluoxetine) β an antidepressant of the SSRI class
Luminal (phenobarbital) β a barbiturate with sedative and hypnotic properties
R
Remeron (mirtazapine) β an atypical antidepressant, used off-label as a sleep aid
Restoril (temazepam) β a benzodiazepine used to treat insomnia
Risperdal (risperidone) β atypical antipsychotic used to treat schizophrenia, bipolar disorder and irritability associated with autism
Ritalin (methylphenidate) β a stimulant used to treat ADHD
ReVia (naltrexone) β an opioid antagonist primarily used in the management of alcohol dependence, opioid dependence or other impulse control/addictive behaviors such as habitual self-mutilation
Rexulti (brexpiprazole) β atypical antipsychotic used to treat mood and psychotic disorders
S
Saphris (asenapine) β atypical antipsychotic used to treat schizophrenia and bipolar disorder
Serax (oxazepam) β anti-anxiety medication of the benzodiazepine class, often used to help during detoxification from alcohol or other addictive substances
Serentil (mesoridazine) β an antipsychotic drug used in the treatment of schizophrenia
Seroquel and Seroquel XR (quetiapine) β atypical antipsychotic used to treat schizophrenia and bipolar disorder. Used off-label to treat insomnia
Sonata (zaleplon) β a non-benzodiazepine hypnotic
Spravato (esketamine) β a rapid-acting antidepressant of the NMDA receptor antagonist class; enantiomer of ketamine
Stelazine (trifluoperazine) β an antipsychotic used in the treatment of psychotic disorders, anxiety, and nausea caused by chemotherapy
Strattera (atomoxetine) β a non-stimulant medication used to treat ADHD
Suboxone (buprenorphine/naloxone) - a partial opioid agonist used in the treatment of opioid use disorder
T
Thorazine (chlorpromazine) β a phenothiazine antipsychotic used to treat schizophrenia, bipolar mania, and behavioral disorders in children. Notably, the first antipsychotic
Tofranil (imipramine) β a tricyclic antidepressant used to treat depression, anxiety, agitation, panic disorder and bedwetting
Topamax (topiramate) β an anticonvulsant used to treat epilepsy and migraine headaches
Trileptal (oxcarbazepine) β an anticonvulsant used as a mood stabilizer
Trintellix (vortioxetine) β an antidepressant of the serotonin modulator and stimulator class
Tegretol (carbamazepine) β an anticonvulsant used as a mood stabilizer
Trilafon (perphenazine)- an antipsychotic used to treat schizophrenia
Tranxene, Novo-Clopate (clorazepate) β a benzodiazepine with anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties
V
Valium (diazepam) β a benzodiazepine used to treat anxiety.
Vistaril (hydroxyzine) β an antihistamine for the treatment of itches and irritations, an antiemetic, as a weak analgesic, an opioid potentiator, and as an anxiolytic
Vyvanse (lisdexamfetamine) β a pro-drug stimulant used to treat attention deficit hyperactivity disorder and binge eating disorder; Vyvanse is converted into Dexedrine in vivo
Viibryd (vilazodone) β an antidepressant of the serotonin modulator and stimulators class
Vivactil (protriptyline) an antidepressant also used in the treatment of nerve pain
Vraylar (cariprazine) β atypical antipsychotic used to treat schizophrenia and bipolar mania
W
Wellbutrin IR, SR or XL (bupropion) β an antidepressant of the norepinephrine-dopamine reuptake inhibitor class, used to treat depression and seasonal affective disorder
X
Xanax (alprazolam) β a benzodiazepine used to treat anxiety
Z
Zoloft (sertraline) β an antidepressant of the SSRI class
Zonegran (zonisamide) β an anticonvulsant used to treat other seizures
Zulresso (brexanolone) β a GABA modulator antidepressant
Zyban (bupropion) β same active ingredient as Wellbutrin, but marketed as a smoking cessation aid
Zyprexa (olanzapine) β atypical antipsychotic used to treat schizophrenia and bipolar disorder
References
Anxiety disorders | List of psychotropic medications | [
"Chemistry"
] | 2,860 | [
"Psychoactive drugs",
"Neurochemistry"
] |
7,381,751 | https://en.wikipedia.org/wiki/Permissiveness%20%28endocrinology%29 | In endocrinology, permissiveness is a biochemical phenomenon in which the presence of one hormone is required in order for another hormone to exert its full effects on a target cell. Hormones can interact in permissive, synergistic, or antagonistic ways. The chemical classes of hormones include amines, polypeptides, glycoproteins and steroids. Permissive hormones act as precursors to active hormones and may be classified as either prohormones or prehormones. It stimulate the formation of receptors of that hormone.
Examples
Thyroid hormone increases the number of beta-adrenergic receptors available for epinephrine at the latter's target cell, thereby increasing epinephrine's effect on that cell. Specially in cardiac cell. Without the thyroid hormone, epinephrine would have only a weak effect.
Cortisol is required for the response of vascular and bronchial smooth muscle to catecholamines. Cortisol is also required for the lipolytic effect of catecholamines, ACTH, and growth hormone on fat cells. Cortisol is also required for the calorigenic effects of glucagon and catecholamines.
The effects of a hormone in the body depend on its concentration. Permissive actions of glucocorticoids like cortisol generally occur at low concentrations. Abnormally high amounts of a hormone can result in atypical effects. Glucocorticoids function by attaching to cytoplasmic receptors to either enhance or suppress changes in the transcription of DNA and thus the synthesis of proteins. Glucocorticoids also inhibit the secretion of cytokines via post-translational modification effects.
References
Biology terminology | Permissiveness (endocrinology) | [
"Chemistry",
"Biology"
] | 364 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry",
"nan"
] |
7,382,070 | https://en.wikipedia.org/wiki/Hourman%20%28Rex%20Tyler%29 | Hourman (Rex Tyler) is a fictional superhero appearing in comics published by DC Comics. He is known as the original Hourman (spelled Hour-Man in his earliest appearances, also referred to as The Hour-Man, and The Hourman). He was created by writer Ken Fitch and artist Bernard Baily in Adventure Comics #48 (April 1940), during the Golden Age of Comic Books. He continued to appear in Adventure Comics until issue #83 (Feb 1943).
Rex Tyler made his live-action debut in the first season of DC's Legends of Tomorrow before becoming a guest star in the second season, portrayed by Patrick J. Adams. Rex Tyler also appeared in the first season of the DC Universe series Stargirl, portrayed by Lou Ferrigno Jr.
Fictional character biography
Scientist Rex Tyler, raised in upstate New York, developed an affinity for chemistry, particularly biochemistry. Working his way through college, he landed a job researching vitamins and hormone supplements at Bannermain Chemical. A series of discoveries and accidents led him to the "miraculous vitamin" Miraclo. He found that concentrated doses of the "miraclo" given to test mice increased their strength and vitality several times that of normal, but only for one hour. After taking a dose himself, Rex found he could have superhuman strength and speed for an hour, before returning to human levels.
Keeping the discovery of Miraclo a secret, Tyler decided that human trials would be limited to the only subject he could trust: himself. Feeling that the Miraclo-induced abilities should be used for good purposes, he decided to use the abilities to help those in need; in other words, he would become a superhero, based in Appleton City. He received his first mission by placing an ad stating that "The Man of The Hour" would help the needy. Tracking down one responder to the ad, he aided a housewife whose husband was falling in with the wrong crowd, and stopped a robbery. Using a costume he found in an abandoned costume shop, he started to adventure as The Hour-Man (later dropping the hyphen). In November 1940 Hourman became one of the founding members of the first superhero team, the Justice Society of America. After leaving the JSA in mid-1941 Tyler became one of Uncle Sam's initial group of Freedom Fighters. He later became part of the wartime All-Star Squadron.
According to Jess Nevins' Encyclopedia of Golden Age Superheroes, "Hourman fights a variety of Doctors: the robot-wielding Dr. Darrk, the hypnotist Dr. Feher, the big-headed genius Dr. Glisten; the occultist and alchemist Dr. Iker; and the bio-engineer Dr. Togg. There is also the 90-Minute Man, who gains Hourman-like powers for 90 minutes from his radium armor".
Hourman was one of many heroes whose popularity began to decline in the post-war years. Eventually, his adventures ended, but with the resurgence of super-heroes in the mid-1950s and early 1960s, interest in the Golden Age heroes returned, and Hourman was soon appearing as a guest star in issues of Justice League of America. Like all the other Golden Agers, he was now considered an elder statesman of the super-hero set.
It is later revealed that Miraclo is addictive and that Rex is struggling with its effects. In Zero Hour: Crisis in Time!, Extant kills Hourman before the Hourman android rescues him and transports him to a pocket dimension.
Rex is later resurrected, retires, and provides technical support for the JSA All-Stars, of whom his son is a member.
In Doomsday Clock, Hourman is erased from existence when Doctor Manhattan alters the timeline, but is resurrected when Superman convinces Manhattan to undo his actions.
Powers and abilities
Through the use of Miraclo, Hourman can possess superhuman strength, speed, stamina, and durability, night vision, underwater survival, and expert martial arts skills for one full hour.
In other media
Television
Rex Tyler appears in the Batman: The Brave and the Bold episode "The Golden Age of Justice!", voiced by Lex Lang. This version uses an hourglass-shaped device to fuel his powers instead of Miraclo and appears as a member of an aged Justice Society of America.
Rex Tyler appears in the Robot Chicken episode "Tapping a Hero", voiced by Seth Green.
Rex Tyler appears in Legends of Tomorrow, portrayed by Patrick J. Adams. This version is the leader of the Justice Society of America, who were active in the 1940s. At the end of the first season, he warns the Legends not to travel to 1942 due to their impending deaths, only to vanish shortly afterwards. In the second season, the team meets Tyler's past self when they ignore his warning. Tyler is later killed by the Reverse-Flash, erasing his future self who had discovered the Reverse-Flash's plans and warned the Legends from existence. Before his death, Rex was in a relationship with Vixen, who goes after and later joins the Legends to avenge Rex.
Rex Tyler appears in Stargirl, portrayed by Lou Ferrigno Jr. This version is a member of the Justice Society of America whose powers are derived from an hourglass amulet. Ten years prior to the series, Rex and his wife Wendi are killed by Solomon Grundy. In the present, Rick Tyler assumes his father's mantle and amulet to avenge his parents' deaths.
Film
Rex Tyler appears in the opening credits of Justice League: The New Frontier, in which he falls to his death while running from police officers due to a ban on vigilantes.
An alternate universe incarnation of Rex Tyler appears in Justice Society: World War II, voiced by Matthew Mercer. This version hails from Earth-2 and is a founding member of the Justice Society of America, who were active during their Earth's version of the titular war.
References
External links
Grand Comics Database
Hourman at Don Markstein's Toonopedia. Archived from the original on February 5, 2016.
Comics Archives: JSA Fact File: Hourman I
DC Indexes: Earth-2 Hourman I
Comics characters introduced in 1940
DC Comics characters with superhuman durability or invulnerability
DC Comics characters with superhuman strength
DC Comics characters who can move at superhuman speeds
DC Comics male superheroes
DC Comics scientists
DC Comics titles
Earth-Two
DC Comics characters with accelerated healing
DC Comics metahumans
DC Comics martial artists
Golden Age superheroes | Hourman (Rex Tyler) | [
"Chemistry"
] | 1,339 | [
"Fictional biochemists",
"Biochemists"
] |
7,382,202 | https://en.wikipedia.org/wiki/IRE%20%28unit%29 | The IRE unit is used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers.
A value of 100 IRE is defined to be +714 mV in an analog NTSC video signal. A value of 0 IRE corresponds to the voltage value of 0 mV, the signal value during the blanking period. The sync pulse is normally 40 IRE below this 0 IRE value, so the total range covered from peak to trough of an all white signal would be 140 IRE.
Video signals use the "IRE" unit instead of DC voltages to describe levels and amplitudes. Based on a standard 1 Vpp NTSC composite-video signal that swings from -286 mV (sync tip) to +714 mV (peak video), a 140 IRE peak-to-peak convention is established. Thus, one NTSC IRE unit is 7.143 mV ( V or mV), where -40 IRE is equivalent to -285.7 mV, and +100 IRE is equivalent to +714.3 mV. 0 IRE is equivalent to 0 V. The black level is equivalent to 53.57 mV (7.5 IRE).
The PAL video signal is slightly different in that it swings from -300 mV to +700 mV, instead. Thus, one PAL IRE unit is 7 mV, where -43 IRE is equivalent to -300 mV at the sync tip, and +100 IRE is equivalent to +700 mV at the peak video level. Black level is the same as the blanking level 0 mV (0 IRE).
The reason IRE is a relative measurement (percent) is because a video signal may be any amplitude. This unit is used in the ITU recommendations BT.470 and BT.1700 which define PAL, NTSC and SECAM:
References
Units of measurement
Broadcast engineering
Video formats
Television technology
ITU-R recommendations | IRE (unit) | [
"Mathematics",
"Technology",
"Engineering"
] | 399 | [
"Information and communications technology",
"Broadcast engineering",
"Television technology",
"Quantity",
"Electronic engineering",
"Units of measurement"
] |
7,382,590 | https://en.wikipedia.org/wiki/XSLT%20elements | XSLT (Extensible Stylesheet Language Transformations) defines many elements to describe the transformations that should be applied to a document. This article lists some of these elements. For an introduction to XSLT, see the main article.
XSLT logic elements
Example XSLT stylesheet using logic elements
<xsl:stylesheet>
<xsl:template match="//input">
<xsl:variable name="type" select="@type"/>
<xsl:variable name="name" select="@name"/>
<xsl:if test="$type='text' or $type='password' or $type='radio' or $type='checkbox'">
<xsl:choose>
<xsl:when test="$type='radio'">
<xsl:if test="not(preceding-sibling::input[@type='radio'])">
<select name="{@name}">
<xsl:for-each select="../input[@name=$name]">
<option value="{@value}">
<xsl:apply-templates/>
</option>
</xsl:for-each>
</select>
</xsl:if>
</xsl:when>
<xsl:when test="$type='text'">
<input name="{@name}" type="{@type}">
<xsl:apply-templates/>
</input>
</xsl:when>
<xsl:when test="$type='password'">
<input name="{@name}" type="{@type}">
<xsl:apply-templates/>
</input>
</xsl:when>
</xsl:choose>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
XSLT file I/O elements
Client-side XSLT can be implemented in a browser by adding a line like the following to the source XML file, right after the root XML tag.
<?xml-stylesheet type="text/xsl" href="family.xsl"?>
This is described on the page http://www.xml.com/pub/a/2000/10/25/msie/index.html
Other XSLT semantics
Functions defined by XSLT
The following functions can occur in many XSLT attributes, such as xsl:value-of.select and xsl:for-each.select.
External links
W3C XSLT 1.0 recommendation - Describes the whole syntax and semantics of XSLT 1.0
W3C XSLT 2.0 recommendation
XSLT Elements Reference - by W3Schools
References
XML-based standards | XSLT elements | [
"Technology"
] | 632 | [
"Computer standards",
"XML-based standards"
] |
7,382,786 | https://en.wikipedia.org/wiki/Metox%20radar%20detector | The R600A Metox, named after its manufacturer, was a pioneering high-frequency radar warning receiver (RWR) used by the German forces on U-boats from 1942β1945. It was initially installed to receive signals transmitted by British radars.
Manufacture and purpose
The Metox was manufactured by a small French company in occupied Paris. It was tuned to receive the signals used by many British radars of the early and mid-Second World War, notably the ASV Mk. II radar used by RAF Coastal Command to detect U-boats. It is not clear whether the design was German or French or both. It was installed on German U-boats starting in 1942 and used until the end of the war. The system given the official title of (FuMB 1, [Radio measuring device]).
British radar
From July 1940, the British fitted the RAF Mk II AI (Airborne Interception) radar into Coastal Command aircraft for use as the Mk II "-metre ASV". The radar suffered from problems due to land clutter and inability to determine height, which caused its failure in night fighters but these were no handicap in this new role. With two range scales, and , it could detect surfaced U-boats at up to and land at up to away, though a typical U-boat detection range was . The radar had a fairly crude display but was able to give the range and an approximate direction within an arc either side of the aircraft heading. Returns were lost in sea clutter once the aircraft was within about of the U-boat but usually by then, the aircraft was within visual range and the U-boat was well into a crash dive.
Leigh light
Wing Commander Humphry de Verde Leigh developed the Leigh light, a powerful floodlight steered by the ASV radar, allowing aircraft to search for U-boats at night. The U-boat was tracked by the radar with the light switched off, following the radar track. Once the returns were lost, the light would be switched on bathing the U-boat in light. The first successful attack was on on 5 July 1942. The sudden light was often the first indication to the U-boat crew that they had been found. The Leigh light was initially very successful, particularly in the Bay of Biscay. Metox was the German answer to the British radar. Metox sets received the transmitted pulses from the ASV and rendered them as audible beeps. It enjoyed the usual advantage of radar detectors over radar in that the signal is direct and only had to travel one way whereas the radar has to detect the very weak reflection from the submarine. Most radars increase the number of pulses and decrease the width of the pulses when switched to a shorter range, the shorter pulse widths allow the radar to look at closer objects. Metox exploited the fact that once the radar operator changed the range indication from to , the pulse repetition frequency of the radar's transmitter doubled. Radar cannot detect any reflections returned earlier than half a pulse width so when the U-boat was closer than the operator would change to the shorter scale. If the Metox set started beeping at twice the rate, the U-boat knew that they had been detected. By the time the aircraft was close enough to the U-boat's position to illuminate with the Leigh light, the U-boat was well under the water. As a bonus, the Metox set would also provide warning in excess of visual range in daylight.
Enigma code
In December 1942 British code breakers regained the ability to decipher messages encrypted with naval four-rotor Enigma machines and the Germans noticed the resulting increase in U-boat sightings. Based on their confidence in the Enigma machine, as well as the testimony of a captured British bomber pilot, the Germans came to the erroneous conclusion that the Allies could detect emissions produced by the Metox. The executive officer of , Captain Herbert Werner said of Metox, "Then, on August 3 [1943], we received a message from Headquarters which had a greater impact on our lives than any since the beginning of the Allied offensive.
Obsolete
Metox was eventually countered by a version of the H2S radar, which Metox could not detect and once again the Leigh light forced U-boat crews to refuse to run surfaced at night. Even during the day the new radar was easily able to detect a submerged U-boat's periscope or snorkel, which earlier radars employing longer wavelengths could not do. Metox was superseded by the Naxos radar detector that detected 10-centimetre wavelength H2S signals but was unable to detect the higher, frequency of the American H2X radar.
References
World War II German electronics
U-boats
World War II German radars
Radar warning receivers
French inventions
Military equipment introduced from 1940 to 1944 | Metox radar detector | [
"Technology"
] | 981 | [
"Warning systems",
"Radar warning receivers"
] |
7,382,910 | https://en.wikipedia.org/wiki/Astrological%20symbols | Historically, astrological and astronomical symbols have overlapped. Frequently used symbols include signs of the zodiac and classical planets. These originate from medieval Byzantine codices. Their current form is a product of the European Renaissance. Other symbols for astrological aspects are used in various astrological traditions.
History and origin
Symbols for the classical planets, zodiac signs, aspects, lots, and the lunar nodes appear in the medieval Byzantine codices in which many ancient horoscopes were preserved. In the original papyri of these Greek horoscopes, there was a circle with the glyph representing shine () for the Sun; and a crescent for the Moon.
Classical planets
The written symbols for Mercury, Venus, Jupiter, and Saturn have been traced to forms found in late Classical Greek papyri. The symbols for Jupiter and Saturn are monograms of the initial letters of the corresponding Greek names, and the symbol for Mercury is a stylized caduceus. A.S.D. Maunder finds antecedents of the planetary symbols in earlier sources, used to represent the gods associated with the classical planets. Bianchini's planisphere, produced in the 2nd century, shows Greek personifications of planetary gods charged with early versions of the planetary symbols: Mercury has a caduceus; Venus has, attached to her necklace, a cord connected to another necklace; Mars, a spear; Jupiter, a staff; Saturn, a scythe; the Sun, a circlet with rays radiating from it; and the Moon, a headdress with a crescent attached. A diagram in Johannes Kamateros' 12th-century Compendium of Astrology shows the Sun represented by the circle with a ray, Jupiter by the letter zeta (the initial of Zeus, Jupiter's counterpart in Greek mythology), Mars by a shield crossed by a spear, and the remaining classical planets by symbols resembling the modern ones, without the cross-mark seen in modern versions of the symbols.
The modern sun symbol, pictured as a circle with a dot (), first appeared in the Renaissance. (The conventional symbols for the signs of the zodiac also develop in the Renaissance period as simplifications of the classical pictorial representations of the signs.)
The modern sun symbol resembles the Egyptian hieroglyph for "sun" β a circle that sometimes had a dot in the center, ().
Similar in appearance were several variants of the ancestral form of the modern Chinese logograph for "sun", which in the oracle bone script and bronze script were .
It is not known if the Egyptian and Chinese logographs have any connection to the European astrological symbol.
Major planets discovered in the modern era
Symbols for Uranus, Neptune and Pluto were created shortly after their discovery. For Uranus, two variant symbols are seen. One symbol, , invented by J. G. KΓΆhler and refined by Bode, was intended to represent the newly discovered metal platinum; since platinum, sometimes described as white gold was found by chemists mixed with iron, the symbol for platinum combines the alchemical symbols for iron, β, and gold, β. An inverted version of that same symbol, was in use in the early 20th century. Another symbol, , was suggested by Lalande in 1784. In a letter to Herschel, Lalande described it as "un globe surmontΓ© par la premiΓ¨re lettre de votre nom" ("a globe surmounted by the first letter of your name"). After Neptune was discovered, the Bureau des Longitudes proposed the name Neptune and the familiar trident for the planet's symbol, though at bottom may be either a cross or an orb .
Pluto, like Uranus, has multiple symbols in use. One symbol, β, is a monogram of the letters PL (which can be interpreted to stand for Pluto or for astronomer Percival Lowell), was announced with the name of the new planet by the discoverers on May 1, 1930. Another symbol, popularized in Paul Clancy's American Astrology magazine, is based on Pluto's bident: .
Asteroids
The astrological symbols for the first four objects discovered at the beginning of the 19th century β Ceres, Pallas, Juno and Vesta β were created shortly after their discoveries. They were initially listed as planets, and half a century later came to be called asteroids, though such "minor planets" continued to be considered planets for perhaps another century. Shortly after Giuseppe Piazzi's discovery of Ceres, a group of astronomers ratified the name, proposed by the discoverer, and chose the sickle as a symbol of the planet. The symbol for Pallas, the spear of Pallas Athena, was invented by Baron Franz Xaver von Zach, and introduced in his Monatliche Correspondenz zur BefΓΆrderung der Erd- und Himmels-Kunde. Karl Ludwig Harding, who discovered and named Juno, assigned to it the symbol of a scepter topped with a star.
The modern astrological form of the symbol for Vesta, βΆ, was created by Eleanor Bach, who is credited with pioneering the use of the big four asteroids with the publication of her Ephemerides of the Asteroids in the early 1970s. The original form of the symbol for Vesta, , was created by German mathematician Carl Friedrich Gauss. Olbers, having previously discovered and named one new planet (as the asteroids were then classified), gave Gauss the honor of naming his newest discovery. Gauss decided to name the planet for the goddess Vesta, and also specified that the symbol should be the altar of the goddess with the sacred fire burning on it.
Bach's variant is a simplification of 19th-century elaborations of Gauss's altar symbol.
Centaurs
The symbol for the centaur Chiron, β·, is both a key and a monogram of the letters O and K (for 'Object Kowal', a provisional name of the object, for discoverer Charles T. Kowal) was proposed by astrologer Al Morrison, who presented the symbol as "an inspiration shared amongst Al H. Morrison, Joelle K.D. Mahoney, and Marlene Bassoff."
A widely used convention for other centaurs, proposed by Robert von Heeren in the 1990s, is to replace the K of the Chiron key glyph with the initial letter of the object: e.g. P or Ο for Pholus and N for Nessus (, ).
Other trans-Neptunian objects
Symbols for other large trans-Neptunian objects have mostly been proposed on the Internet; some created by Denis Moskowitz have been used by NASA
and are used by the popular open-source astrological software Astrolog, as well as being used less consistently by commercial programs.
Miscellaneous orbital stations
The symbol for retrograde motion is , a capital 'R' with a tail stroke. An 'R' with a tail stroke was used to abbreviate many words beginning with the letter 'R'; in medical prescriptions, it abbreviated the word recipe (from the Latin imperative of recipere "to take"), and in missals, an R with a tail stroke marked the responses.
Meanings of the symbols
Signs of the zodiac
Planets
Asteroids and other celestial bodies
Since the 1970s, some astrologers have used asteroids and other celestial bodies in their horoscopes. The symbol for the first-recognised centaur, 2060 Chiron, was devised by Al H. Morrison soon after it had been discovered by Charles Kowal, and has become standard amongst astrologers. In the late 1990s, German astrologer Robert von Heeren created symbols for other centaurs based on the Chiron model, though only those for 5145 Pholus and 7066 Nessus are included in Unicode, and only that for Pholus in Astrolog. The following list is by no means exhaustive, but for bodies outside this list, there is often very little to no independent usage beyond the symbols' creators.
The Hamburg School of Astrology, also called Uranian Astrology, is a sub-variety of western astrology. It adds eight fictitious trans-Neptunian planets to the normal ones used by western astrologers:
Aspects
In astrology, an aspect is an angle the planets make to each other in the horoscope, also to the ascendant, midheaven, descendant, lower midheaven, and other points of astrological interest. The following symbols are used to note aspect:
Russian aspects
In addition to the aspect symbols above, some Russian astrologers use additional or unique aspect symbols:
Miscellaneous symbols
See also
Alchemical symbols
Aztec calendar
Behenian fixed star
Classical elements
Earthly Branches
Gender symbols
Heavenly Stems
Maya calendar
Monas Hieroglyphica
Planet symbol
Nakshatra
Navagraha
Sexagenary cycle
Sri Rama Chakra
Vedic astrology
Notes
References
External links
Glyphs and keywords for asteroids (often different from the astronomical ones)
Symbols
Astronomical symbols
Religious symbols
Symbols
Western astrological signs
Heraldic charges
Unicode | Astrological symbols | [
"Astronomy",
"Mathematics"
] | 1,855 | [
"Symbols",
"Astrology",
"Astronomical symbols",
"History of astronomy"
] |
7,383,487 | https://en.wikipedia.org/wiki/Oospore | An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. They are believed to have evolved either through the fusion of two species or the chemically induced stimulation of mycelia, leading to oospore formation.
In Oomycetes, oospores can also result from asexual reproduction, by apomixis. These haploid, non-motile spores are the site of meiosis and karyogamy in oomycetes.
A dormant oospore, when observed under an electron microscope, has led researchers to draw conclusion that there is only a single central globule with other storage bodies surrounding it.
References
Reproduction | Oospore | [
"Biology"
] | 157 | [
"Biological interactions",
"Behavior",
"Reproduction"
] |
7,383,878 | https://en.wikipedia.org/wiki/Overdrafting | Overdrafting is the process of extracting groundwater beyond the equilibrium yield of an aquifer. Groundwater is one of the largest sources of fresh water and is found underground. The primary cause of groundwater depletion is the excessive pumping of groundwater up from underground aquifers. Insufficient recharge can lead to depletion, reducing the usefulness of the aquifer for humans. Depletion can also have impacts on the environment around the aquifer, such as soil compression and land subsidence, local climatic change, soil chemistry changes, and other deterioration of the local environment.
There are two sets of yields: safe yield and sustainable yield. Safe yield is the amount of groundwater that can be withdrawn over a period of time without exceeding the long-term recharge rate or affecting the aquifer integrity. Sustainable yield is the amount of water extraction that can be sustained indefinitely without negative hydrological impacts, taking into account both recharge rate and surface water impacts.
There are two types of aquifers: confined and unconfined. In confined aquifers, there is an overbearing layer called an aquitard, which contains impermeable materials through which groundwater cannot be extracted. In unconfined aquifers, there is no aquitard, and groundwater can be freely extracted from the surface. Extracting groundwater from unconfined aquifers is like borrowing the water: it has to be recharged at a proper rate. Recharge can happen through artificial recharge and natural recharge.
Mechanism
When groundwater is extracted from an aquifer, a cone of depression is created around the well. As the drafting of water continues, the cone increases in radius. Extracting too much water (overdrafting) can lead to negative impacts such as a drop of the water table, land subsidence, and loss of surface water reaching the streams. In extreme cases, the supply of water that naturally recharges the aquifer is pulled directly from streams and rivers, lowering their water levels. This affects wildlife, as well as humans who might be using the water for other purposes.
The natural process of aquifer recharge takes place through the percolation of surface water. An aquifer may be artificially recharged, such as by pumping reclaimed water from wastewater management projects directly into the aquifer. An example of is the Orange County Water District in California. This organization takes wastewater, treats it to a proper level, and then systematically pumps it back into the aquifers for artificial recharge.
Since every groundwater basin recharges at a different rate depending on precipitation, vegetative cover, and soil conservation practices, the quantity of groundwater that can be safely pumped varies greatly among regions of the world and even within provinces. Some aquifers require a very long time to recharge, and thus overdrafting can effectively dry up certain sub-surface water supplies. Subsidence occurs when excessive groundwater is extracted from rocks that support more weight when saturated. This can lead to a capacity reduction in the aquifer.
Changes in freshwater availability stem from natural and human activities (in conjunction with climate change) that interfere with groundwater recharge patterns. One of the leading anthropogenic activities causing groundwater depletion is irrigation. Roughly 40% of global irrigation is supported by groundwater, and irrigation is the primary activity causing groundwater storage loss across the U.S.
Around the world
This ranking is based on the amount of groundwater each country uses for agriculture. This issue is becoming significant in the United States (most notably in California), but it has been an ongoing problem in other parts of the world, such as was documented in Punjab, India, in 1987.
United States
In the U.S., an estimated 800Β km3 of groundwater was depleted during the 20th century. The development of cities and other areas of highly concentrated water usage has created a strain on groundwater resources. In post-development scenarios, interactions between surface water and groundwater are reduced; there is less intermixing between the surface and subsurface (interflow), leading to depleted water tables.
Groundwater recharge rates are also affected by rising temperatures which increase surface evaporation and transpiration, resulting in decreased water content of the soil. Anthropogenic changes to groundwater storage, such as over-pumping and the depletion of water tables combined with climate change, effectively reshape the hydrosphere and impact the ecosystems that depend on the groundwater.
Accelerated decline in subterranean reservoirs
According to a 2013 report by research hydrologist Leonard F. Konikow at the United States Geological Survey (USGS), the depletion of the Ogallala Aquifer between 20012008 is about 32% of the cumulative depletion during the entire 20th century. In the United States, the biggest users of water from aquifers include agricultural irrigation, and oil and coal extraction. According to Konikow, "Cumulative total groundwater depletion in the United States accelerated in the late 1940s and continued at an almost steady linear rate through the end of the century. In addition to widely recognized environmental consequences, groundwater depletion also adversely impacts the long-term sustainability of groundwater supplies to help meet the Nation's water needs."
As reported by another USGS study of withdrawals from 66 major US aquifers, the three greatest uses of water extracted from aquifers were irrigation (68%), public water supply (19%), and "self-supplied industrial" (4%). The remaining 8% of groundwater withdrawals were for "self-supplied domestic, aquaculture, livestock, mining, and thermoelectric power uses."
Environmental impacts
Groundwater extraction for use in water supplies lowers the overall water table, the level that groundwater sits at in an area. The lowering water table can diminish streamflow and reduce water level in other water bodies such as wetlands and lakes. In Karst systems, large-scale groundwater withdrawal can lead to sinkholes or groundwater-related subsidence. The overdrafting leads to the pressure in limestone containments to become unstable and sediments to collapse, creating a sinkhole. Overdrafting in coastal regions can lead to the reduction of water pressure in an aquifer, allowing saltwater intrusion. If saltwater contaminates a freshwater aquifer, that aquifer can no longer be used as a reliable source of freshwater for settlements and cities. Artificial recharge may return fresh water pressure to halt saltwater intrusion. However, this method can be economically inefficient and unavailable due to the high cost of the process.
When aquifers or groundwater wells experience overdraft, chemical concentrations in the water may change. Chemicals such as calcium, magnesium, sodium, carbonate, bicarbonate, chloride, and sulfate can be found in groundwater sources. Changes to water quality as a result of overdrafting may make it unsafe for human consumption; rendering the groundwater sources unusable as a source of drinking water.
Overdrafting can also affect organisms living within groundwater aquifers known as stygobionts Loss of habitat for these creatures through overdrafting has reduced biodiversity in certain areas.
Environmental impacts of overdrafting include:
Groundwater-related subsidence: the collapse of land due to lack of support (from the water that is being depleted). The first recorded case of land subsidence was in the 1940s. Land subsidence can be as little as local land collapsing or as large as an entire region's land being lowered. The subsidence can lead to infrastructural and ecosystem damage.
Lowering of the water table, which makes water harder to reach streams and rivers
Reduction of water volume in streams and lakes because their supply of water is being diminished by surface water recharging the aquifers
Impacts on animals that depend on streams and lakes for food, water, and habitat
Deterioration to water quality
Increase in the cost of water to the consumer due to a lower water tableβmore energy is needed to pump from a greater depth, so operating costs increase for companies, who pass on the expense to the consumer
Decrease in crop production from lack of water
Disturbances to the water cycle
Groundwater related subsidence
Socio-economic effects
Overdrafting has socio-economic impacts due to cost inequities that increase as the water table drops. As the water table drops, deeper wells are required to reach water in the aquifer. This not only requires deepening of already existing wells, but also digging new wells. Both processes are expensive. Research from Punjab found that the high cost of technology to continue water access hurts small landholders more than it does large landholders because large landholders have more resources "to invest in technology." Therefore, small landholders, who traditionally have a lower income than large landholders, are unable to benefit from the technology that allows greater water access. This creates a cycle of inequity as small landholders that are dependent on agriculture have less water to irrigate their land, producing a lower output of crops.
Additionally, overdrafting has socio-economic impacts due to prior appropriation laws. Prior appropriation rights declare that the first person to use water from a water source will maintain the right to water. These rights result in socio-economic inequities as businesses and/or larger landholders who have a higher income can maintain their water rights. Meanwhile, new businesses or smaller landholders have less access to water, resulting in less ability to profit. Due to this inequity, small farmers in Punjab with less water rights tend to grow maize or less productive rice; meanwhile, larger landholders in Punjab can use more land for rice because they have access to water.
Possible solutions
Artificial Recharge:
Since recharge is the natural replenishment of water, artificial recharge is the man-made replenishment of groundwater, though there is only a limited amount of suitable water available for replenishing.
Water Conservation Techniques:
Other solutions include implementing water conservation techniques to decrease overdrafting. These include improving governance to ensure proper water management, incentivizing water conservation, improving agriculture techniques to ensure water use is efficient, changing diets to crops that require less water, and investing in infrastructure that uses water sustainably. The state of California has implemented some water conservation techniques due to droughts in the state. Some of their techniques include prohibitions on: 1) outdoor watering that runs onto sidewalks or other on hard surfaces that don't absorb water, 2) washing vehicles with a hose that does not have a shutoff handle, 3) watering within 48 hours after a quarter inch of rain, and 4) watering commercial/industrial decorative grass.
Water Conservation Incentivization:
Techniques used by California in emergency situations are useful; however, incentive to follow through on these is important. The city of Spokane has a program to incentivize sustainable landscapes called SpokaneScape. This program incentivizes water efficient landscapes by offering homeowners up to $500 in credit on their utility bill if they adapt their yards to water efficient plants.
See also
Cone of depression
Groundwater recharge
Groundwater-related subsidence
Drinking water
Overexploitation
Water crisis
Human overpopulation
References
External links
The Perils of Groundwater Pumping, Issues in Science and Technology
Aquifers
Environmental impact of agriculture
Environmental issues with water
Water supply
Water and the environment | Overdrafting | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 2,345 | [
"Hydrology",
"Aquifers",
"Water supply",
"Environmental engineering"
] |
7,384,025 | https://en.wikipedia.org/wiki/Astronomische%20Gesellschaft%20Katalog | The Astronomische Gesellschaft Katalog (AGK) is an astrometric star catalogue of the Northern hemisphere. It was published in 3 versions from 1890 until 1975, named AGK1, AGK2 and AGK3.
History
Compilation for the first version, Astronomische Gesellschaft Katalog 1 AGK1, was started in 1867, directed by Friedrich Argelander and published between 1890 (three sections from the observatories at Oslo, Helsinki, and NeuchΓ’tel Observatory) and 1924 (final section: Algiers Observatory), listing 200Β 000 stars down to ninth magnitude.
The second version, AGK2, was started in the 1920s, and published between 1951 and 1958 using photographic data obtained from the Bonn and Hamburg Observatories.
Karl Friedrich KΓΌstner was involved in the planning for star catalog AGK2 with the Bonn part then directed by Ernst Arnold KohlschΓΌtter.
The third version, AGK3, was started in 1956 and published in 1975. It contains 183,145 stars north of declination β2Β° with mean positional errors of Β±0.13" and mean proper motion errors of Β±0.009"/year.
See also
Hoher List Observatory
References
DavidDarling.info
Astro.it
External links
AGK3 query form from VizieR
Astronomical catalogues of stars | Astronomische Gesellschaft Katalog | [
"Astronomy"
] | 274 | [
"Astronomical catalogue stubs",
"Astronomy stubs"
] |
7,384,771 | https://en.wikipedia.org/wiki/Router%20alert%20label | In MPLS, a label with the value of 1 represents the router alert label. This label value is legal anywhere in the label stack except at the bottom. When a received packet contains this label value at the top of the label stack, it is delivered to a local software module for processing. The actual forwarding of the packet is determined by the label beneath it in the stack. However, if the packet is forwarded further, the Router Alert Label should be pushed back onto the label stack before forwarding. The use of this label is analogous to the use of the "Router Alert" option in IPv4 packets. Since this label cannot occur at the bottom of the stack, it is not associated with a particular network-layer protocol.
External links
http://www.cisco.com/warp/public/105/mpls_faq_4649.shtml
MPLS Label Stack Encoding RFC
IP Router Alert Option RFC
MPLS networking
Internet Standards
Network protocols
Tunneling protocols | Router alert label | [
"Technology",
"Engineering"
] | 207 | [
"Computing stubs",
"Computer networks engineering",
"Tunneling protocols",
"Computer network stubs"
] |
7,384,821 | https://en.wikipedia.org/wiki/Guerbet%20reaction | The Guerbet reaction, named after Marcel Guerbet (1861β1938), is an organic reaction that converts a primary alcohol into its Ξ²-alkylated dimer alcohol with loss of one equivalent of water. The process is of interest because it converts simple inexpensive feedstocks into more valuable products. Its main disadvantage is that the reaction produces mixtures.
Scope and applications
The original 1899 publication concerned the conversion of n-butanol to 2-ethylhexanol. 2-ethylhexanol is however more easily prepared by alternative methods (from butyraldehyde by aldol condensation).
Instead, the Guerbet reaction is mainly applied to fatty alcohols to afford oily products, which are called Guerbet alcohols. They are of commercial interest to as components of cosmetics, plasticizers, and related applications. The reaction is conducted in the temperature range 180-360 Β°C, often in a sealed reactor. The reaction requires alkali metal hydroxides or alkoxides. Catalysts such as Raney Nickel are required to facilitate the hydrogen transfer steps.
While the Guerbet reaction is traditionally (and commercially) focused on fatty alcohols, it has been investigated for the dimerization of ethanol to butanol.
Organometallic catalysts have been investigated. A small amount of the diene 1,7-octadiene is required as a hydrogen acceptor.
Mechanism
The reaction mechanism for this reaction is a four-step sequence. In the first step the alcohol is oxidized to the aldehyde. These intermediates then react in an aldol condensation to the allyl aldehyde which the hydrogenation catalyst then reduces to the alcohol.
The Cannizzaro reaction is a competing reaction when two aldehyde molecules react by disproportionation to form the corresponding alcohol and carboxylic acid. Another side reaction is the Tishchenko reaction.
See also
Oxo alcohols - a different reaction which gives similar products
Guerbet alcohols
2-Ethyl-1-butanol
2-Ethylhexanol
2-Propylheptan-1-ol
2-Butyl-1-octanol
2-Butyl-1-octanol
References
External links
A Review of Guerbet Chemistry Anthony J. OβLenick, Jr. https://web.archive.org/web/20110209074739/http://www.zenitech.com/ Link
Condensation reactions
Name reactions
Fatty alcohols | Guerbet reaction | [
"Chemistry"
] | 532 | [
"Name reactions",
"Condensation reactions",
"Organic reactions"
] |
7,384,888 | https://en.wikipedia.org/wiki/Pole%20Hill | Pole Hill is a hill in Chingford, East London, on the border between Greater London and Essex. From its summit there is an extensive view over much of east, north and west London, although in the summer the leaves of the trees in Epping Forest have a tendency to mask some of the view to the north and west.
Origin of name
The earliest recording of the name is as "Pouls Fee" or "Pauls Fee" in 1498. It is shown as Hawke Hill on the Chapman and AndrΓ© map of 1777. Hawke derives from the nearby Hawkwood. Hawk is the Old English for a nook, cranny or corner and so means wood at the corner of the parish (of Chingford).
It was named Paul because it was in the manor of Chingford Pauli, also known as Chingford St Paul's, which belonged to St Paul's Cathedral in London. Fee is from the Middle English fe which means a landed estate indicating it formed part of the manor. After the erection of the Greenwich Meridian obelisk mentioned below, it appears to have acquired the cognomen of Polar Hill, but this soon dropped out of use.
Astronomical history
The hill stands in Epping Forest at 0 degrees longitude, and 51 degrees 38 minutes north latitude. At its highest point it is above sea level. It is noted for the fact that it lies directly on the Greenwich meridian and, being the highest point on that bearing directly visible from Greenwich, was at one time used as a marker by geographers at the observatory there to set their telescopes and observation equipment to a true zero degree bearing.
On the summit of the hill is an obelisk made of granite and bearing the following inscription:
This pillar was erected in 1824 under the direction of the Reverend John Pond, MA, Astronomer Royal. It was placed on the Greenwich Meridian and its purpose was to indicate the direction of true north from the transit telescope of the Royal Observatory. The Greenwich Meridian as changed in 1850 and adopted by international agreement in 1884 as the line of zero longitude passes 19 feet to the east of this pillar.
At that point ( east) there is an Ordnance Survey trig point placed here to mark the top of the hill.
Famous connections
T. E. Lawrence once owned a considerable amount of land on the western side of the hill. Lawrence first rented the land, then began buying it in small parcels after the war. He dreamed of setting up a private press to print fine-edition books with his friend from Oxford, Vyvyan Richards.
Enthused with the ideals of medievalism and craftsmanship in the style of William Morris, they planned to house their press in a medieval-style timber hall to be designed by the architect Herbert Baker and built himself a small hut there in which he lived for several years. Lawrence's hut was dismantled in 1930 and rebuilt in The Warren, Loughton.
References
Epping Forest District
Hills of Essex
Hills of London
History of astronomy | Pole Hill | [
"Astronomy"
] | 602 | [
"History of astronomy"
] |
7,385,054 | https://en.wikipedia.org/wiki/List%20of%20gemstones%20by%20species | This is a list of gemstones, organized by species and types.
Minerals
There are over 300 types of minerals that have been used as gemstones. Such as:
AβB
Actinolite
Nephrite ()
Adamite
Aegirine
Afghanite
Agrellite
Algodonite
Alunite
Amblygonite
Analcime
Anatase
Andalusite
Chiastolite
Andesine
Anglesite
Anhydrite
Annabergite
Anorthite
Antigorite
Bowenite
Apatite
Apophyllite
Aragonite
Arfvedsonite
Asbestos
Astrophyllite
Atacamite
Augelite
Austinite
Axinite group:
Ferroaxinite
Magnesioaxinite
Manganaxinite
Tinzenite
Azurmalachite
Azurite
Baryte
Bastnaesite
Bayldonite
Benitoite
Beryl subgroup:
Aquamarine
Maxixe
Emerald
Trapiche emerald ()
Goshenite
Golden beryl
Heliodor
Morganite
Red beryl (Bixbite)
Beryllonite
Beudantite
Bismutotantalite
Biotite
Boleite
Boracite
Bornite
Brazilianite
Breithauptite
Brookite
Brucite
Bustamite
Bytownite
CβF
Calcite
Manganoan calcite ()
Caledonite
Canasite
Cancrinite
Vishnevite
Carletonite
Carnallite
Cassiterite
Catapleiite
Cavansite
Celestite
Ceruleite
Cerussite
Chabazite
Chalcopyrite
Chambersite
Charlesite
Charoite
Childrenite
Chiolite
Chondrodite
Chrysoberyl
Alexandrite ()
Cymophane
Chromite
Chrysocolla
Chrysotile
Cinnabar
Clinochlore
Clinohumite
Clinozoisite
Clintonite
Cobaltite
Colemanite
Cordierite
Iolite ()
Cornwallite
Corundum
Ruby ()
Sapphire ()
Padparadscha
Golden sheen sapphire
Covellite
Creedite
Crocoite
Cryolite
Cumberlandite
Cuprite
Danburite
Datolite
Descloizite
Diamond
Bort
Ballas
Diaspore
Dickinsonite
Diopside
Dioptase
Dolomite
Dumortierite
Ekanite
Elbaite
Enstatite
Bronzite
Hypersthene
Eosphorite
Epidote
Piemontite
Erythrite
Esperite
Ettringite
Euclase
Eudialyte
Euxenite
Fayalite
Feldspar subgroup:
Andesine
Albite
Anorthite
Anorthoclase
Amazonite
Bytownite
Celsian
Microcline
Moonstone
Adularia ()
Rainbow ()
Orthoclase
Unakite
Plagioclase
Albite
Labradorite
Oligoclase
Sanidine
Sunstone
Oregon sunstone
Rainbow lattice sunstone
Fergusonite
Ferroaxinite
Fluorapatite
Fluorapophyllite
Fluorite
Forsterite
Friedelite
GβL
Gadolinite
Gahnite
Gahnospinel
Garnet group:
Pyralspite
Almandine
Pyrope
Spessartine
Ugrandite
Andradite
Demantoid
Melanite
Topazolite
Grossular
Hessonite
Hydrogrossular
Tsavorite
Uvarovite
Almandine-pyrope
Rhodolite
Andradite-grossular
Grandite (Mali garnet)
Pyrope-almandine-spessartine
Malaia garnet
Pyrope-spessartine
Umbalite
Gaspeite
Gaylussite
Gibbsite
Glaucophane
Goethite
Goosecreekite
Grandidierite
Gypsum
Gyrolite
Halite
Hambergite
Hanksite
Hardystonite
Hauyne
Helenite
Hematite
Hemimorphite
Herderite
Hexagonite
Hibonite
Hiddenite
Hodgkinsonite
Holtite
Howlite
Huebnerite
Humite
Hureaulite
Hurlbutite
Hyperitdiabas
Ilmenite
Inderite
Jade
Jadeite
Chloromelanite
Nephrite
Jasper
Jeremejevite
Kainite
KΓ€mmererite
Kaolinite
Kornerupine
Kutnohorite
Kurnakovite
Kyanite
Langbeinite
Lawsonite
Lazulite
Lazurite
Legrandite
Lepidolite
Leucite
Leucophanite
Linarite
Lizardite
Londonite
Ludlamite
Ludwigite
MβQ
Magnesite
Malachite
Marialite-meionite
Wernerite ()
Marcasite
Meliphanite
Mellite
Mesolite
Microcline
Microlite
Milarite
Millerite
Mimetite
Monazite
Mordenite
Mottramite
Muscovite
Fuchsite ()
Musgravite
Nambulite
Narsarsukite
Natrolite
Nepheline
Neptunite
Nickeline (Niccolite)
Nosean
Nuummite
Olivine
Opal
Fire opal
Moss opal
Painite
Palygorskite
Papagoite
Pargasite
Parisite
Pectolite
Larimar
Pentlandite
Peridot
Periclase
Perthite
Petalite (castorite)
Pezzottaite
Phenakite
Phlogopite
Phosgenite
Phosphophyllite
Phosphosiderite
Piemontite
Pietersite
Plumbogummite
Pollucite
Polyhalite
Poudretteite
Powellite
Prehnite
Prismatine
Prosopite
Proustite
Psilomelane
Pumpellyite
Chlorastrolite ()
Purpurite
Pyrite
Pyrargyrite
Pyromorphite
Pyrophyllite
Pyroxmangite
Pyrrhotite
Quartz
Amethyst ()
Ametrine ()
Aventurine ()
Chalcedony ()
Agate
Iris agate
Onyx
Sardonyx
Bloodstone (Heliotrope)
Carnelian
Chrome chalcedony
Chrysoprase
Dendritic agate
Moss agate
Fire agate (iridescent )
Jasper
Petrified wood
Sard
Citrine ()
Druzy ()
Flint ()
Herkimer diamond ()
Milky quartz ()
Prasiolite ()
Radiolarite ()
Rose quartz ()
Rock crystal ()
Shocked quartz ()
Smoky quartz ()
Quartzite
RβZ
Realgar
Rhodizite
Rhodochrosite
Rhodonite
Richterite
Riebeckite
Crocidolite ()
Rosasite
Rutile
Samarskite
Sanidine
Sapphirine
Sarcolite
Scapolite
Marialite
Meionite
Scheelite
Schizolite
Scorodite
Selenite
Sellaite
Senarmontite
Sepiolite (Meerschaum)
SΓ©randite
Seraphinite
Serendibite
Serpentine subgroup
Antigorite
Bowenite
Chrysotile
Lizardite
Stichtite
Shattuckite
Shigaite
Shortite
Shungite
Siderite
Sillimanite
Simpsonite
Sinhalite
Smaltite
Smithsonite
Sodalite
Hackmanite ()
Sogdianite
Sperrylite
Spessartite
Sphalerite
Spinel
Ceylonite ()
Spodumene
Hiddenite ()
Kunzite ()
Triphane ()
Spurrite
Staurolite
Stibiotantalite
Stichtite
Stolzite
Strontianite
Strontium titanate
Sulfur
Sugilite
Bustamite ()
Richterite ()
Sylvite
Taaffeite
Talc
Tantalite
Tektites
Moldavite
Tephroite
Thomsonite
Thaumasite
Tinaksite
Titanite (sphene)
Topaz
Tourmaline subgroup:
Achroite ()
Chrome ()
Dravite
Elbaite
Fluor-liddicoatite
Indicolite
Olenite
Paraiba ()
Rossmanite
Rubellite ()
Tremolite
Hexagonite ()
Triphylite
Triplite
Tugtupite
Turquoise
Ulexite
Ussingite
Vanadinite
Variscite
VΓ€yrynenite
Vesuvianite (idocrase)
Californite ()
Villiaumite
Vivianite
Vlasovite
Wardite
Wavellite
Weloganite
Whewellite
Wilkeite
Willemite
Witherite
Wollastonite
Wulfenite
Wurtzite
Xonotlite
Yugawaralite
Zektzerite
Zeolites
Analcime
Apophyllite
Chabazite
Goosecreekite
Natrolite
Scolecite
Stellerite
Stilbite
Thomsonite
Zincite
Zinnwaldite
Zircon
Jacinth ()
Zoisite
Tanzanite ()
Thulite ()
Zultanite
Zunyite
Artificial and lab created
There are a number of artificial and lab grown minerals used to produce gemstones. These include:
Lab alexandrite
Lab corundum
Cubic zirconia
Lab diamond
Lab emerald
Fordite
Gadolinium gallium garnet
Lab moissanite
Synthetic opal
Metal-coated crystals hyped as rainbow quartz
Lab spinel
Synthetic turquoise
Terbium gallium garnet
Trinitite
Yttrium aluminium garnet
Yttrium iron garnet
Organic
There are a number of organic materials used as gems, including:
Amber
Ammolite
Ammonoidea
Bone
Copal
Coral
Ivory
Jet
Nacre (Mother of pearl)
Operculum
Pearl
Seashell
Rocks
Some rocks are used as gems, including:
Anthracite
Anyolite
Bauxite
Concretions
Bloodstone (Heliotrope)
Eilat stone
Epidosite
Glimmerite
Goldstone (glittering glass)
Tiger's eye
Helenite (artificial glass made from volcanic ash)
Iddingsite
Kimberlite
Lamproite
Lapis lazuli
Libyan desert glass
Llanite
Maw sit sit
Moldavite
Obsidian
Apache tears
Pallasite
Peridotite (also known as olivinite)
SiilinjΓ€rvi carbonatite
Soapstone (also known as steatite)
Tactite
Tiger's eye
Unakite
Chatoyant gems
Some minerals made into gemstones may display a chatoyancy or cat's eye effect, these include:
Actinolite
Andalusite
Apatite
Beryl
Aquamarine
Emerald
Heliodor
Morganite
Beryllium
Beryllonite
Calcite
Cerussite
Chrysoberyl
Danburite
Diaspore
Diopside
Enstatite
Garnet
Grandidierite
Hawk's eye
Hypersthene
Iolite
Kornerupine
Kunzite
Kyanite
Moonstone
Opal
Peridot
Peristerite (Albite variety)
Pezzottaite
Phenakite
Prasiolite
Prehnite
Quartz
Rhodonite
Rutile
Scapolite
Selenite
Serpentine
Antigorite
Bowenite
Sillimanite
Smoky Quartz
Spinel
Sunstone
Tanzanite
Tiger's Eye
Topaz
Tourmaline
Ulexite
Zircon
Asterism
Corundum
Ruby
Sapphire
Diopside
See also
List of individual gemstones
References
Further reading
Gemstones of the World revised 5th edition, 2013 by Walter Schumann
Smithsonian Handbook: Gemstones by Cally Hall, 2nd ed. 2002
Species | List of gemstones by species | [
"Physics"
] | 2,270 | [
"Materials",
"Gemstones",
"Matter"
] |
7,385,204 | https://en.wikipedia.org/wiki/MTD%20%28mobile%20network%29 | MTD (Swedish abbreviation for Mobiltelefonisystem D, or Mobile telephony system D) was a manual mobile phone system for the 450Β MHz frequency band. It was introduced in 1971 in Sweden, and lasted until 1987, when it was made obsolete by the NMT automatic service. The MTD network had 20,000 users at its peak, with 700 people employed as phone operators.
MTD was also implemented in Denmark and in Norway (from 1976), which allowed roaming within the Scandinavian countries.
MTA
In Sweden, the first mobile phone system was MTA (for Mobiltelefonisystem A), which was introduced in 1956, and lasted until 1967. It was a 160Β MHz system available in Stockholm and Gothenburg, with 125 total subscribers. The second system, MTB (for Mobiltelefonisystem B), had transistorized mobile sets, was introduced in 1962, and lasted until 1983. It operated in the 76β77.5 and 81β82.5Β MHz bands, was also available in MalmΓΆ, and had around 600 subscribers.
OLT
In Norway, the first mobile phone system was OLT, introduced in 1966. In 1976, the OLT system was extended to include UHF bands, incorporating MTD, and allowing international roaming within Sweden.
References
External links
Brief description of MTD as well as MTA and MTB
Mobile radio telephone systems | MTD (mobile network) | [
"Technology"
] | 288 | [
"Mobile telecommunications",
"Mobile radio telephone systems"
] |
7,385,565 | https://en.wikipedia.org/wiki/Thue%20number | In the mathematical area of graph theory, the Thue number of a graph is a variation of the chromatic index, defined by and named after mathematician Axel Thue, who studied the squarefree words used to define this number.
Alon et al. define a nonrepetitive coloring of a graph to be an assignment of colors to the edges of the graph, such that there does not exist any even-length simple path in the graph in which the colors of the edges in the first half of the path form the same sequence as the colors of the edges in the second half of the path. The Thue number of a graph is the minimum number of colors needed in any nonrepetitive coloring.
Variations on this concept involving vertex colorings or more general walks on a graph have been studied by several authors including BarΓ‘t and VarjΓΊ, BarΓ‘t and Wood (2005), BreΕ‘ar and KlavΕΎar (2004), and KΓΌndgen and Pelsmajer.
Example
Consider a pentagon, that is, a cycle of five vertices. If we color the edges with two colors, some two adjacent edges will have the same color x; the path formed by those two edges will have the repetitive color sequence xx. If we color the edges with three colors, one of the three colors will be used only once; the path of four edges formed by the other two colors will either have two consecutive edges or will form the repetitive color sequence xyxy. However, with four colors it is not difficult to avoid all repetitions. Therefore, the Thue number of C5 is four.
Results
Alon et al. use the LovΓ‘sz local lemma to prove that the Thue number of any graph is at most quadratic in its maximum degree; they provide an example showing that for some graphs this quadratic dependence is necessary. In addition they show that the Thue number of a path of four or more vertices is exactly three, that the Thue number of any cycle is at most four, and that the Thue number of the Petersen graph is exactly five.
The known cycles with Thue number four are C5, C7, C9, C10, C14, and C17. Alon et al. conjecture that the Thue number of any larger cycle is three; they verified computationally that the cycles listed above are the only ones of length β€ 2001 with Thue number four. Currie resolved this in a 2002 paper, showing that all cycles with 18 or more vertices have Thue number 3.
Computational complexity
Testing whether a coloring has a repetitive path is in NP, so testing whether a coloring is nonrepetitive is in co-NP, and Manin showed that it is co-NP-complete. The problem of finding such a coloring belongs to in the polynomial hierarchy, and again Manin showed that it is complete for this level.
References
External links
Graph invariants
Graph coloring
Combinatorics on words | Thue number | [
"Mathematics"
] | 599 | [
"Graph coloring",
"Graph theory",
"Combinatorics",
"Graph invariants",
"Mathematical relations",
"Combinatorics on words"
] |
7,385,837 | https://en.wikipedia.org/wiki/Entertainment%20Consumers%20Association | Entertainment Consumers Association (ECA) is a United Statesβbased non-partisan, non-government, non-profit organization dedicated to the interests of individuals who play computer and video games in the United States and Canada.
History
Hal Halpin, a game industry veteran and former president of the Interactive Entertainment Merchants Association (IEMA) β now called the Entertainment Merchants Association (EMA) β founded ECA in July 2006. The concept of the ECA was born following an IEMA board of directors meeting, in which Halpin recognized a need for consumer representation. The association was launched as a means for consumer rights advocacy following a string of anti-games legislation aimed at criminalizing the sale of certain video games. Although publishers were effectively represented by Entertainment Software Association (ESA) and retailers by Entertainment Merchants Association (EMA), consumers of video games were virtually unrepresented until the launch of ECA. Halpin was still president of the association as of April 2021.
Activities
ECA is an ardent supporter of consumer rights and advocacy, specifically in defending and advancing the interests of gamers. The organization does this through a variety of initiatives including netroots and lobbying efforts at the state and national governmental level, an activity permitted by its 501(c)(4) status. ECA also coalition builds with like-minded organizations including First Amendment advocacy groups and parallel trade associations. The ECA is non-partisan and does not support, oppose or give money to any candidates or political parties.
The ECA Member division negotiates and offers reduced rates for members with various companies that sell game-related merchandise and services including; magazine and premium website subscriptions, discounts on game rentals and purchases and free or discounted admission to trade shows, conferences and concerts, etc. They provide programs for reduced-cost medical and life insurance, financial aid, tuition assistance and scholarship opportunities for members as well as career advice, job boards, resume writing aid and discussion forums and boards.
The association distinguished itself early by weighing in publicly on issues that the parallel trade associations did not, including standing in defense of the game Mass Effect and its developer, BioWare, during the related controversy surrounding supposed sexualization of the product. ECA issued a press statement calling on FOX News to retract the misleading story. ECA also was a founding member of the Gamers for Net Neutrality initiative, which sought to educate and empower gamer consumers about the issues surrounding network neutrality as it relates to online gaming. Partnering with MoveOn.org, SaveTheInternet.com, and Games for Change, the coalition provides an educational area on ECA's website as well as digital advocacy tools for gamers. The association also established several other digital advocacy sub-groups including Gamers for Digital Rights, Gamers for Universal Broadband. Membership is not required to participate in any of the three grass roots initiatives.
On May 12, 2010, the ECA announced that they would be submitting an amicus curiae (friend of the court) document in support of the gaming industry in the Schwarzenegger v. EMA First Amendment case. The organization also stated that they intend to amend a consumer petition to their brief to request that the court find that games should continue to enjoy the same First Amendment protections as music and movies and not be legislated and regulated like alcohol, tobacco and firearms.
The State of California's case is an appeal urging the Court to adopt a new constitutional standard that would enable states to ban the sale or rental of violent video games for those under age 18. The Ninth Circuit Court previously found that there was no proof that playing such games would cause physical or psychological harm to minors. The appeals court also said the law was not the least-restrictive approach to protecting children from exposure to such games.
ECA was a coalition partner with Reddit, Google, EFF, Public Knowledge, Major League Gaming, Demand Progress and others in opposing the Stop Online Piracy Act (SOPA) and its counterpart, the Protect Intellectual Property Act (PIPA). The association also stood opposed to the Copyright Modernization Act in Canada and the Anti-Counterfeiting Trade Agreement (ACTA), internationally.
GamePolitics.com
The ECA merged a number of long-standing staple brands when forming the organization which lent it early credibility and built-in expertise in the respective fields. Among the more prominent brands was GamePolitics.com, a blog originally written and maintained by Dennis McCauley, now run by game journalist Pete Gallagher, the former Editor-in-Chief of GameDaily.com. GP, as it had come to be known in the business and by the site's fans, is an information portal for all matters related to game legislation and grass roots lobbying initiatives.
The organization also publishes a daily email-based electronic newsletter, ECA Today, which is mailed nightly to all members. The newsletter informs and educates gamers about current and potential anti-games legislation, and acts as a call to arms in the association's grass roots lobbying initiatives employing electronic advocacy. ECA also emails out a monthly members-only newsletter which keeps members abreast of the efforts being undertaken and advises the membership of new partnerships and coalitions it has joined. The final two products are GameJobs.com, an interactive entertainment industry job board, and Video Game Yellow Pages (VGYP), which has served for over ten years as an online directory information for the games business.
GameCulture.com
On December 5, 2007, the ECA announced that the association was launching another publication, called GameCulture. Journalist and co-author of SmartBomb: The Quest for Art, Entertainment, and Big Bucks in the Videogame Revolution, Aaron Ruby, was hired on to be the Editor-in-Chief. The association felt the need to launch the site as a resource for promoting gaming in a more positive light and addressing the ways in which gamers and gaming have impacted broader society. In September 2009, GameCulture added veteran game journalist, John Keefer to its ranks who was followed by New Zealandβbased writer, Julie Gray, in January 2010. Popular web comic, Experience Points, penned by Scott Johnson, moved from its original home at Crispy Gamer to GameCulture.
Controversy
On December 2, 2009, controversy arose regarding the ECA's membership cancellation policy, in which the association's membership terms and conditions were changed without notifying ECA users. The change was made due to an exploit in a partner's coupon codes. The cancellation policy change temporarily required that members mail a physical letter requesting cancellation while the association upgraded their systems. There were also complaints about the change in the terms and conditions being made without notifying the membership, which struck some members as ironic given the ECA's stance regarding End User License Agreements.
The three-week ordeal ended on December 24, 2009 once the promised new modules went public giving members online account termination and an online auto-renewal opt-out functionality similar to Xbox Live and ECA's listing with the CT Better Business Bureau was raised to an Aβ.
On February 6, 2013, the ECA announced via Facebook their appointment of "Gerard Williams" aka "The Hip Hop Gamer". as their video game ambassador. The appointment was received with negative reception by gamers and gaming press who felt that his reputation of verbally/physically threatening others and use of the word 'faggot' would hurt the image and cause of gamers as a consumer group. Heather Ellertson, the ECA's Vice President of Marketing sent out a press release saying that Gerard was in the process of turning his life around and they "wanted to give him the opportunity to be a voice for gamers and a positive role model for gaming". The ECA & 'Hip Hop Gamer Inc' then announced via their Facebook page that all complaints, comments and criticisms should be directed to The Hip Hop Gamer himself and that he did not represent the views of any of their partners or sponsors. Gerard Williams then published a video explaining that he had only used the word 'faggot' because someone told him to 'shut up' during a Sony press event.
Support
Member dues
The ECA receives financial support from its dues-paying membership β individuals who pay $19.99 annually ($14.99 for students and members of the military). The association claims not to accept funding from industry partners, nor does it permit game publisher advertising on any of its websites or publications, though open job placements on the ECA's GameJobs.com are paid-for by game industry companies. The organisation also receives additional pro bono legal assistance from Hughes Hubbard & Reed.
The last year in which the ECA reported revenue was 2018.
Sponsors
Additionally, the association lists the brands and companies which are marketing partners with the ECA on their website. Most provide discounts and special promotions, but none provide funding.
See also
Consumer
Gamer
Digital Rights
Player (game)
References
External links
Entertainment Consumers Association
Advocacy groups
Video game culture
Information technology organizations based in North America
Non-profit organizations based in Connecticut
Video game organizations
Consumer organizations in the United States
Non-profit technology
Organizations established in 2006
501(c)(4) nonprofit organizations
Digital rights organizations | Entertainment Consumers Association | [
"Technology"
] | 1,884 | [
"Information technology",
"Non-profit technology"
] |
7,386,145 | https://en.wikipedia.org/wiki/Type%20erasure | In programming languages, type erasure is the load-time process by which explicit type annotations are removed from a program, before it is executed at run-time. Operational semantics not requiring programs to be accompanied by types are named type-erasure semantics, in contrast with type-passing semantics. Type-erasure semantics is an abstraction principle, ensuring that the run-time execution of a program doesn't depend on type information. In the context of generic programming, the opposite of type erasure is named reification.
Type inference
The reverse operation is named type inference. Though type erasure can be an easy way to define typing over implicitly typed languages (an implicitly typed term is well-typed if and only if it is the erasure of a well-typed explicitly typed lambda term), it doesn't provide Rule of inference for this definition.
See also
Template (C++)
Problems with type erasure (in Generics in Java)
Monomorphization
Type polymorphism
References
Type theory | Type erasure | [
"Mathematics",
"Technology"
] | 209 | [
"Mathematical structures",
"Mathematical logic",
"Mathematical objects",
"Computer science stubs",
"Type theory",
"Computer science",
"Computing stubs"
] |
7,387,672 | https://en.wikipedia.org/wiki/Yuri%20Filipchenko | Yuri Aleksandrovich Filipchenko, sometimes Philipchenko (; 1882 β 1930) was a Russian entomologist who coined the terms microevolution and macroevolution, as well as the mentor of geneticist Theodosius Dobzhansky. Though he himself was an orthogeneticist, he was one of the first scientists to incorporate the laws of Mendel into evolutionary theory and thus had a great influence on The Modern Synthesis. He established a genetics laboratory in Leningrad undertaking experimental work with Drosophila melanogaster. Theodosius Dobzhansky worked with him from 1924. Filipchenko is also known for his work in Soviet eugenics, though his work in the subject would later result in his public denunciation due to the rise of Stalinism and increased criticisms that eugenics represented bourgeois science.
Biography
Early life and education
Yuri Filipchenko was born on February 13, 1882, in Zlyn' in Bolkhovsky District of the Russian Empire. His father was Aleksandrovich Efimovich, a landowner and agriculturalist. Filipchenko also had a brother by the name of Aleksandr Aleksandrovich, who would later become a parasitologist and physician.
He received his secondary education at the Second Saint Petersburg Classical Gymnasium. In 1897, Filipchenko read Darwinβs On the Origin of Species and Sexual Selection for the first time. Two years later, he would read Carl NΓ€geliβs Mechanisch-physiologische Theorie der Abstamungslehre. These two works would later have a powerful formative influence on Filipchenko and helped to steer him towards a career in zoology.
Filipchenko graduated from Second Saint Petersburg in 1900, but due to a variety of financial difficulties that were further complicated by his father's death, he entered the Military Medical Academy. However, Filipchenko soon transferred to the natural science division at Saint Petersburg State University only a year after entering the academy.
Filipchenko was arrested in December 1905 due to being present at a meeting of the Soviet Workers' Deputies, but was released shortly afterwards. However, Filipchenko was arrested later the same month after helping to organize workers in the Nevsky District of Saint Petersburg, serving four months in prison during which he studied both philosophy and for government examinations. Though he would later join the Schlisselburg Committee, which assisted with the plight of political prisoners, and the Socialist Revolutionary Party, Filipchenko stepped away from politics after 1906 to focus his attention on scientific pursuits.
After graduating from Saint Petersburg State University's Zoology Department in 1906, Filipchenko was accepted to Saint Petersburg State University's Zoology and Comparative Anatomy Master's program in 1910. He pursued comparative embryology for his candidate's thesis due to his interest in the presentation and evolution of physical characteristics in animals. By engaging in a project that allowed him to compare the embryonic development in higher-level taxa (i.e. class, orders, etc.), Filipchenko gained a broader perspective on inheritance that would later inform his ideas on macroevolution.
Career
Filipchenko created the first department of genetics in Russia at Saint Petersburg State University in 1919, which would, by 1921, become the Bureau of Eugenics at the Russian Academy of Sciences in Saint Petersburg. In later years, the Bureau would be renamed the Bureau of Genetics and Eugenics in 1925 and finally the Laboratory of Genetics in 1930, but regardless of its name, the work of the institution would go on to form the foundation of the Institute of Genetics at the USSR Academy of Science.
However, in the wake of the first five-year plan, Filipchenko became publicly castigated for his work in orthogenesis and in eugenics and was relieved of his position at Saint Petersburg State University in 1930. His Laboratory of Genetics and Experimental Zoology was disbanded shortly afterward.
Personal life
Filipchenko was married to Nadezhda Pavlovna, with whom he had a son by the name of Gleb, who was a physicist. Both Nadezhda and Gleb were killed during the blockade of Leningrad in World War II.
Death
Filipchenko developed a severe headache whilst working at Peterhof, and concerned about his health, traveled to Leningrad to be taken care of by his brother Aleksandr. While in Leningrad, Filipchenko contracted streptococcal meningitis and later died at midnight between May 19 and May 20, 1930. His head was donated to Bekhterevβs Brain Institute for research, while the rest of his remains were buried in Smolensky Cemetery.
Scientific career
VariabilitΓ€t und Variation
In his 1927 German text VariabilitΓ€t und Variation, Filipchenko introduced the idea of two separate forms of evolution: evolution within a species, or microevolution, and evolution that occurs in higher taxonomic categories, which he termed macroevolution. While microevolution was governed by a system of inheritance dictated by genetics, Filipchenko based macroevolution on cytoplasmic variability rather than genetic inheritance.
Views on Darwin
Though evolution was embraced by many Russian biologists in Filipchenko's day, there did exist elements of opposition to Darwin's ideas, most commonly in the form of "direct evolution," or orthogenesis. While Filipchenko self-identified as a Darwinist, he only did so in the sense that he believed in the idea of evolution. He did not subscribe to the belief that Darwin's concept of natural selection was as integral to the process of evolution as Darwin espoused, instead positing that evolution was not governed by the principles of Lamarck or natural selection, but rather was intrinsic to life itself. Filipchenko believed that evolution in animals and plants was an inherent developmental process rather than a change induced over successive generations, a process that an organism's environment can affect, but only indirectly.
Involvement in Eugenics
Filipchenko's investigations into genetics, craniometry, the inheritance of quantitative characters, and neurology eventually introduced him to ideas on eugenics that were being developed by his contemporaries in the United States and Europe. These ideas on eugenics proved so powerful to Filipchenko that he himself began to write papers and give lectures on the subject in 1918. Filipchenko would later go on to form the Russian Eugenics Society in Moscow in 1920, as well as the Bureau of Eugenics in February 1921, an independent eugenics research institution in Petrograd. Ultimately, Filipchenko, along with Nikolai Koltsov, would become the main leaders of the Russian eugenics movement.
Filipchenko was drawn to eugenics due to both its potential to be used as a "civic religion" and its promise of a better future for the Soviets, but also due to the immense amount of funding directed towards eugenics due to the Soviet government's interest in the subject. Eugenics seemed to be the practical application of genetics relative to human health, and since this fact dovetailed with the Soviet penchant for scientific social planning, and so Soviet institutions like the Commissariat of Public Health poured funding into the subject.
Filipchenko and his Bureau of Eugenics created charts of the pedigrees of various Soviet academics and intellectuals in an attempt to ascertain the location of "race" within an individual. But Filipchenko was staunchly against Bolshevik ideas regarding the sterilization of undesirables and mass insemination of women by men with exceptional genetics, stating that such acts were "crude assaults on the human person" and that the best way to create a "desirable breed" was through positive selection. In Filipchenko's eyes, eugenic progress could only be achieved through education rather than legislative or scientific methods.
However, by 1925, the appeal of Soviet eugenics had waned due to issues outside of just the negative aspects of the subject. A great controversy arose regarding the compatibility of genetics, and by extension eugenics, with Marxist science. Filipchenko, in an attempt to defend eugenicsβ relevance to Marxist dialectic, argued against Lamarckism, the other theory on inheritance that some Soviet scientists had argued was more compatible with the tenets of Marxism, by stating that if it were true, then the negative qualities that Lamarckism associated with poverty and the lower class would have prevented them from rising up against the bourgeoisie in the first place.
Despite eugenics surviving the conflict between genetics and Lamarckism, Filipchenko's work in eugenics was effectively cut short with the emergence of the Great Break (USSR) in 1929. During this period, eugenics was referred to as a βbourgeois doctrine,β and as such the USSR would become the first country to officially ban the subject. Filipchenko's work in the subject would later be one of the key reasons for his dismissal from Saint Petersburg in 1930.
Impact
Filipchenko was the first professor in Russia to introduce genetics at the collegiate level due to his annual course on inheritance Petersburg University, which he started teaching in 1913. He was also the first to publish a textbook on the subject of inheritance and genetics in Russia, which was called Nasledstvennost'''. His articles and textbooks on inheritance were some of the first entry points for Russian biologists like Dobzhansky to modern genetics, and it is for this reason that Soviet botanist and historian Peter Zhukovsky once called Filipchenko "the teacher of our youth."
Published works
During his career, Filipchenko published more than 100 works in Russian, 20 works in German, and 4 works in French, often under the name "J.A. Philiptschenko." Below are a few of the articles he put out in his lifetime.
Razvitie izotomy (The development of isotomes; St. Petersburg, 1912)
Izmenchivostβ i evoliutsiia (Variation and evolution; Petrograd and Moscow, 1915; 2nd ed., Petersburg, 1921)
Proiskhozhdenie domashnykh zhivotnykh (The origin of domesticated animals; Petrograd, 1916; 2nd ed., Leningrad, 1924)
Nasledstvennostβ (Heredity; Moscow, 1917; 2nd ed., 1924; 3rd ed., 1926)
Chto takoe evgenika? (What is eugenics?; Petrograd. 1921)
Kak nasleduetsia razlichnye osobennosti cheloveka (How various human traits are inherited; Petrograd, 1921)
Izmenchivost i metody ee izucheniia (Variation and methods for its study: Petrograd, 1923;2nd ed. Leningrad 1926; 3rd ed., 1927; 4th ed., Moscow and Leningrad 1929)
Obshchedostupnaia biologiia (Biology for the general reader; Petrograd, 1923; 15th ed., 1930)
Evoliutsionnaia ideia v biologii (The evolutionary idea in biology; Moscow, 1923; 2nd ed., 1926; 3rd ed., 1977)
Puti uluchsheniia chelovecheskogo roda (evgenika) (Ways of improving the human race [eugenics]; Leningrad, 1924)
"Frensis Galβton i Gregor Mendelβ (Francis Galton and Gregor Mendel; Moscow, 1925)
Besedy o zhivykh sushchestvakh (Conversations about living substances; Leningrad, 1925)
Nasledstvenny li priobretennye priznaki? (Are acquired characteristics inherited?: Leningrad. 1925)
Variabilitat und variation (Berlin, 1927)
I, Rasteniia (Plants; Leningrad, 1927)
II, Zhivotnye (Animals; Leningrad, 1928)
Genetika i ee znachenie dlia zhivotnovodstva (Genetics and its significance for animal breeding; Moscow and Leningrad, 1931)
Eksperimental naia zoologiia (Experimental zoology; Leningrad and Moscow, 1932)
Genetika Miagkikh pshenits'' (The genetics of soft wheats; Moscow and Leningrad, 1934)
References
People from Oryol Oblast
Russian entomologists
1882 births
1930 deaths
Soviet entomologists
Orthogenesis
Russian scientists | Yuri Filipchenko | [
"Biology"
] | 2,538 | [
"Orthogenesis",
"Non-Darwinian evolution",
"Biology theories",
"Obsolete biology theories"
] |
4,237,693 | https://en.wikipedia.org/wiki/Spurline | The spurline is a type of radio-frequency and microwave distributed element filter with band-stop (notch) characteristics, most commonly used with microstrip transmission lines. Spurlines usually exhibit moderate to narrow-band rejection, at about 10% around the central frequency.
Spurline filters are very convenient for dense integrated circuits because of their inherently compact design and ease of integration: they occupy surface that corresponds only to a quarter-wavelength transmission line.
Structure description
It consists of a normal microstrip line breaking into a pair of smaller coupled lines that rejoin after a quarter-wavelength distance. Only one of the input ports of the coupled lines is connected to the feed microstrip, as shown in the figure below. The orange area of the illustration is the microstrip transmission line conductor and the gray color the exposed dielectric.
Where is the wavelength corresponding to the central rejection frequency of the bandstop filter, measured - of course - in the microstrip line material. This is the most important parameter of the filter that sets the rejection band.
The distance between the two coupled lines can be selected appropriately to fine-tune the filter. The smaller the distance, the narrower the stop-band in terms of rejection. Of course that is limited by the circuit-board printing resolution, and it is usually considered at about 10% of the input microstrip width.
The gap between the input microstrip line and the one open-circuited line of the coupler has a negligible effect on the frequency response of the filter. Therefore, it is considered approximately equal to the distance of the two coupled lines.
Printed antennae
Spurlines can also be used in printed antennae such as the planar inverted-F antenna. The additional resonances can be designed to widen the antenna bandwidth or to create multiple bands, for instance, for a tri-band mobile phone.
History
A spurline filter was first proposed by Schiffman and Matthaei in stripline form in 1964. Bates adapted the design for microstrip in 1977. Nguyen and Hsieh improved the analysis for microstrip implementations in 1983.
References
C. Nguyen and K. Chang, βOn the analysis and design of spurline bandstop filters,β IEEE Trans. Microw. Theory Tech., vol. 33, no. 12, pp.Β 1416β1421, Dec. 1985.
Primary sources
B. M. Schiffman; G. L. Matthaei, "Exact design of band-stop microwave filters", IEEE Transactions on Microwave Theory and Techniques, vol. 12, iss. 1, pp. 6-15, 1964.
R. N. Bates, "Design of microstrip spur-line band-stop filters", IEEE Journal on Microwave Optics and Acoustics, vol. 1, iss. 6, pp. 209-204, November 1977.
C. Nguyen; C. Hsieh, Millimeter wave printed circuit spurline filters", IEEE MTT-S International Microwave Symposium Digest, pp. 98-100, 1983.
Microwave technology
Distributed element circuits | Spurline | [
"Engineering"
] | 624 | [
"Electronic engineering",
"Distributed element circuits"
] |
4,237,747 | https://en.wikipedia.org/wiki/Simulated%20fluorescence%20process%20algorithm | The Simulated Fluorescence Process (SFP) is a computing algorithm used for scientific visualization of 3D data from, for example, fluorescence microscopes. By modeling a physical light/matter interaction process, an image can be computed which shows the data as it would have appeared in reality when viewed under these conditions.
Principle
The algorithm considers a virtual light source producing excitation light that illuminates the object. This casts shadows either on parts of the object itself or on other objects below it. The interaction between the excitation light and the object provokes the emission light, which also interacts with the object before it finally reaches the eye of the viewer.
See also
Computer graphics lighting
Rendering (computer graphics)
References
External links
Freeware SFP renderer
Computational science
Computer graphics algorithms
Visualization (graphics)
Microscopes
Microscopy
Fluorescence | Simulated fluorescence process algorithm | [
"Physics",
"Chemistry",
"Astronomy",
"Mathematics",
"Technology",
"Engineering"
] | 171 | [
"Spectroscopy stubs",
"Luminescence",
"Fluorescence",
"Spectrum (physical sciences)",
"Applied mathematics",
"Astronomy stubs",
"Measuring instruments",
"Computational science",
"Microscopes",
"Microscopy",
"Molecular physics stubs",
"Spectroscopy",
"Physical chemistry stubs"
] |
4,237,868 | https://en.wikipedia.org/wiki/Winged%20sun | The winged sun is a solar symbol associated with divinity, royalty, and power in the Ancient Near East (Egypt, Mesopotamia, Anatolia, and Persia). The Illyrian Sun-deity is also represented as a winged sun.
Ancient Egypt
In ancient Egypt, the symbol is attested from the Old Kingdom (Sneferu, 26th century BC ), often flanked on either side with a uraeus.
Behdety
In early Egyptian religion, the symbol Behdety represented Horus of Edfu, later identified with Ra-Horakhty. It is sometimes depicted on the neck of Apis, the bull of Ptah. As time passed (according to interpretation) all of the subordinated gods of Egypt were considered to be aspects of the sun god, including Khepri. The name "Behdety" means the inhabitant of Behdet.
He was the sky god of the region called Behdet in the Nile basin.
His image was first found in the inscription on a comb's body, as a winged solar panel. The period of the comb is about 3000 BC. Such winged solar panels were later found in the funeral picture of Pharaoh Sahure of the fifth dynasty. Behdety is seen as the protector of Pharaoh. On both sides of his picture are seen the Uraeus, which is a symbol for the cobra-headed goddess Wadjet.
He resisted the intense heat of Egyptian sun with his two wings.
Mesopotamia
From roughly 2000 BCE, the symbol also appears in Mesopotamia. It appears in reliefs with Assyrian rulers as a symbol for royalty, transcribed into Latin as (literally, "his own self, the Sun", i.e. "His Majesty").
Illyria
Early figurative evidence of the celestial cult in Illyria is provided by 6th century BCE plaques from Lake Shkodra, which belonged to the Illyrian tribal area of what was referred in historical sources to as the Labeatae in later times. Each of those plaques portray simultaneously sacred representations of the sky and the sun, and symbolism of lightning and fire, as well as the sacred tree and birds (eagles). In those plaques there is a recurrent mythological representation of the celestial deity: the Sun deity animated with a face and two wings, throwing lightning into a fire altar, which in some plaques is held by two men (sometimes on two boats).
Iran
In Zoroastrian Persia, the symbol of the winged sun became part of the iconography of the Faravahar, the symbol of the divine power and royal glory in Persian culture.
Judah
From around the 8th century BC, the winged solar disk appears on Hebrew seals connected to the royal house of the Kingdom of Judah. Many of these are seals and jar handles from Hezekiah's reign, together with the inscription l'melekh ("belonging to the king"). Typically, Hezekiah's royal seals feature two downward-pointing wings and six rays emanating from the central sun disk, and some are flanked on either side with the Egyptian ankh ("key of life") symbol. Prior to this, there are examples from the seals of servants of king Ahaz and of king Uzziah.
Compare also Malachi 4:2, referring to a winged "Sun of righteousness",
Greece
The winged sun is conventionally depicted as the knob of the caduceus, the staff of Hermes.
Modern use
Various groups such as Freemasonry, Rosicrucianism, Thelema, Theosophy, and Unity Church have also used it. The symbol was used on the cover of Charles Taze Russell's textbook series Studies in the Scriptures beginning with the 1911 editions.
The winged sun symbol is also cited by proponents of the pseudoscientific Nibiru cataclysm.
Implied Secular use
A winged sun is used in the heraldry of the North America Trade Directory.
Variations of the symbol are used as a trademark logo on vehicles produced by the Chrysler Corporation, Mini, Bentley Motors, Lagonda (Aston Martin) and Harley Davidson.
Since WW2, military aircraft of the United States have carried the insignia of a circle with stripes extending from each side like wings. Whether this is coincidental or some symbolic resemblance was intended is unknown. A five-pointed star is inscribed within the circle.
Regarding its video game usage, the symbol has become a common motif in the Sonic the Hedgehog franchise, most notably featured on title screens displaying the main character, as well as a stylized version appearing as a symbol for religious mechanics and buildings in Civilization VI, among others.
See also
Winged genie
References
Bibliography
R. Mayer, Opificius, Die geflΓΌgelte Sonne, Himmels- und Regendarstellungen im Alten Vorderasien, UF 16 (1984) 189-236.
D. Parayre, Carchemish entre Anatolie et Syrie Γ travers l'image du disque solaire ailΓ© (ca. 1800-717 av. J.-C.), Hethitica 8 (1987) 319-360.
D. Parayre, Les cachets ouest-sΓ©mitiques Γ travers l'image du disque solaire ailΓ©, Syria 67 (1990) 269-314.
External links
Relief Depicting Gilgamesh Between Two Bull-Men Supporting a Winged Sun Disk, Kapara palace, Tell Halaf.
Ancient Egyptian symbols
Egyptian hieroglyphs
Heraldic charges
Middle Eastern mythology
Religious symbols
Solar symbols
Sun myths
Divinity
Horus
Ra | Winged sun | [
"Astronomy"
] | 1,131 | [
"Astronomical myths",
"Sun myths"
] |
4,238,168 | https://en.wikipedia.org/wiki/Reference%20card | A reference card or reference sheet (or quick reference card) or crib sheet is a concise bundling of condensed notes about a specific topic, such as mathematical formulas to calculate area/volume, or common syntactic rules and idioms of a particular computer platform, application program, or formal language. It serves as an ad hoc memory aid for an experienced user.
In spite of what the name reference card may suggest, such as a 3x5 index card (), the term also applies to sheets of paper or online pages, as in the context of programming languages or markup languages.
However, this concept is now being adopted to portray concise information in many other fields.
Appearance
As in the examples below, reference cards are typically one to a few pages in length. Pages are organized into one or more columns. Across the columns, the reference is split into sections and organized by topic. Each section contains a list of entries, with each entry containing a term and its description and usage information. Terms might include keywords, syntactic constructs, functions, methods, or macros in a computer language. In a reference card for a program with a graphical user interface, terms may include menu entries, icons or key combinations representing program actions.
Due to its logical structure and conciseness, finding information in a reference card is trivial for humans and requires no computer interaction. It is therefore convenient for a user to print out a reference card. While reference cards can be printed on card stock, it is common to print them on ordinary printer paper. With the advent of portable electronic devices that can display documents, digital reference cards stored in PDF or HTML formats have become more common. This is in contrast to user guides, which tend to be rather long and verbose and which have (in comparison to reference cards) a lower information density
Examples
Wikimedia wiki syntax ref card meta:Help:Reference card
A LaTeX reference sheet: PDF
An AMS LaTeX reference card: PDF
An R reference card: PDF
An R reference card for data mining: www.rdatamining.com
A CC (common criteria) quick reference card for security product evaluation:
See also
Cheat sheet
User guide
Crib sheet
References
Technical communication
pl:ΕciΔ
ga#Inne rodzaje ΕciΔ
g | Reference card | [
"Technology"
] | 466 | [
"Computing stubs"
] |
4,238,207 | https://en.wikipedia.org/wiki/Cadernos%20Pagu | Cadernos Pagu is a Brazilian academic journal on gender studies and sexuality. It was established in 1993 at the Universidade Estadual de Campinas. Pagu was the nickname of PatrΓcia GalvΓ£o, an iconic Brazilian feminist. The journal is published in Portuguese and the editor-in-chief is Leila Mezan Algranti (Universidade Estadual de Campinas).
Abstracting and indexing
The journal is abstracted and indexed in:
Sociological Abstracts
MLA International Bibliography
International Bibliography of Periodical Literature
International Bibliography of Book Reviews of Scholarly Literature
References
External links
Online access at SciELO
Gender studies journals
Sexology journals
Academic journals established in 1993
Portuguese-language journals | Cadernos Pagu | [
"Biology"
] | 136 | [
"Behavior",
"Sexuality stubs",
"Sexuality"
] |
4,238,602 | https://en.wikipedia.org/wiki/Urchin%20%28software%29 | Urchin was a web statistics analysis program that was developed by Urchin Software Corporation. Urchin analyzed web server log file content and displayed the traffic information on that website based upon the log data. Sales of Urchin products ended on March 28, 2012.
Urchin software could be run in two different data collection modes: log file analyzer or hybrid. As a log file analyzer, Urchin processed web server log files in a variety of log file formats. Custom file formats could also be defined. As a hybrid, Urchin combined page tags with log file data to eradicate the limitations of each data collection method in isolation. The result was more accurate web visitor data.
Urchin became one of the more popular solutions for website traffic analysis, particularly with ISPs and web hosting providers. This was largely due to its scalability in performance and its pricing model.
Urchin Software Corp. was acquired by Google in April 2005, forming Google Analytics. In April 2008, Google released Urchin 6. In February 2009, Google released Urchin 6.5, integrating AdWords. Urchin 7 was released in September 2010 and included 64-bit support, a new UI, and event tracking, among other features.
See also
UTM parameters
List of web analytics software
References
External links
Google software
Web analytics
Discontinued Google services
Web log analysis software | Urchin (software) | [
"Technology"
] | 270 | [
"Web log analysis software",
"Computer logging"
] |
4,238,932 | https://en.wikipedia.org/wiki/Glow%20plate | Glow plates are sheets of glass or plastic that "glow" when light is supplied to one of their edges.
The light source for a glow plate can be artificial, such as fluorescent light, or natural, with sunlight being directly exposed to the plate or fed through a fiber-optic system.
A joint effort between Florida State University and Oak Ridge National Laboratory is focused on the design of a "spiral bio-reactor light sheet", which consists of a plexiglas sheet that has been micro-etched on one side and rolled into a spiral shape.
Aside from aesthetic or utilitarian lighting purposes, much interest in using glow plates as a source of light comes from recent developments in algal cultivation.
External links
Algae used to mitigate carbon dioxide emissions The energy blog
Fabrication of spiral bio-reactor light sheets Student abstracts: engineering at ORNL
Lighting
Fiber optics
Algaculture | Glow plate | [
"Biology"
] | 177 | [
"Algaculture",
"Algae"
] |
4,239,005 | https://en.wikipedia.org/wiki/Formative%20context | Formative contexts are the institutional and imaginative arrangements that shape a society's conflicts and resolutions. They are the structures that limit both the practice and the imaginative possibilities in a socio-political order, and in doing so shape the routines of conflict over social, political and economic resources that govern access to labor, loyalty, and social station, e.g. government power, economic capital, technological expertise, etc. In a formative context, the institutions structure conflict over government power and capital allocation, whereas the imaginative framework shapes the preconceptions about possible forms of human interaction. Through this, a formative context further creates and sustains a set of roles and ranks, which mold conflict over the mastery of resources and the shaping of the ideas of social possibilities, identities and interests. The formative context of the Western democracies, for example, include the organization of production through managers and laborers, a set of laws administering capital, a state in relation to the citizen, and a social division of labor.
Background
Also referred to as order, framework, or structure of social life, the concept of formative context was developed by philosopher and social theorist Roberto Unger. Whereas other social and political philosophers have taken the historical context as a given, and seen one existing set of institutional arrangements as necessarily giving birth to another set, Unger rejects this naturalization of the world and moves to explain how such contexts are made and reproduced. The most forceful articulation and development of the concept is in Unger's book False Necessity.
The thesis of formative context is central to Unger's theory of false necessity, which rejects the idea of a closed number of institutional arrangements of human societies, e.g. feudalism and capitalism, and that these arrangements are the product of historical necessity, as theories of liberalism or Marxism claim. Rather, Unger argues that there are myriad institutional arrangements that can coalesce, and that they do so through a contingent process of struggle, reconciliation, and innovation among individuals and groups. For Unger, the concept of formative context serves to explain the basis of a certain set of institutional arrangements and their reliance upon each other. It offers an explanation of the cycles of reform and retrenchment of a socio-economic political system and how it remains undisturbed by rivalries and animosities. The theory of false necessity goes on to explain the connections of a formative context, their making and remaking, and how they maintain stability despite the contingent formation.
Criteria
While a formative context of a society exerts a major influence on the course of social actions and behaviors, it is itself hard to challenge, revise, or even identify in the midst of everyday conflicts and routines. Thus there are two kinds of criteria for determining if an institution or structure belongs in a formative context, subjective and objective ones. The subjective criteria consider the perspective of the social actors themselves and the arrangements that are assumed in their speech and actions. For example, the attempts of big business and labor to protect themselves through deals with each other, and the political efforts of unorganized labor and petty bourgeoisie to undermine and circumvent these deals by pressuring the government, operate on the same institutional assumption of the distinction between economy and polity, and that victory in one can be offset by the other. The objective criteria are simply that if a substitution of the proposed structure affects the hierarchies or cyclical conflictsβif it alters the social divisionsβthen it can be included in the formative context. For example, a change in any one of the following conditions would completely change the formative context of a Western democratic state: if the state stopped being democratic or was democratic enough to allow collective militancy and subject private centers of power to public accountability; if business could have its way and override all regulatory controls of govt; or if no workers could unionize or all of them could and did.
Western democracies
The formative context of the North Atlantic democracies can be organized into four clusters of institutional arrangements: work, law, government, and occupational structure.
The work-organization complex makes a distinction in work between task definers and task executers, with the material rewards concentrated in the task defining jobs.
The private-rights complex understands the rights of the individual vis-a-vis other individuals and the state. This structure is central to the allocation and control of capital, ensuring all forms of capital distribution and entitlement.
The government-organization complex is the institutional arrangement to protect the individual from the state, and to prevent those in power from changing the formative context. It establishes a link between safeguards of freedom and the dispersion of powers, e.g. partisan rivalries fail to extend to debates over the fundamental institutions that affect social interactions.
The occupational-structure complex is a social division of labor characterized by a lack of caste or religious division. It is based on material reward and task defining jobs receiving the highest pay.
Influences in other fields
The thesis of formative contexts has been heavily drawn on and used within the Social Study of Information Systems. In the field of Information systems Claudio Ciborra and Giovan Lanzara define the term "formative context" as the "set of institutional arrangements and cognitive imageries that inform actors' practical and reasoning routines in organisations". They posit that the common inability to inquire into, challenge or shape formative context can inhibit individuals and organizations from acting competently and learning what they need to know in order to make the most of situations and technological transitions as the enchaining effect of Formative Context can lead to cognitive and social inertia.
See also
Empowered democracy
Negative capability
Structure and agency
References
Further reading
Information systems
Social philosophy
Social theories
Majorityβminority relations | Formative context | [
"Technology"
] | 1,175 | [
"Information systems",
"Information technology"
] |
4,239,129 | https://en.wikipedia.org/wiki/Social%20Study%20of%20Information%20Systems | The Social Study of Information Systems (SSIS) is interested in people developing and using technology and the "culture" of those people.
SSIS studies these phenomena by drawing on and using "lenses" provided by social sciences, including philosophy, sociology, social psychology, organisational theory, political science.
Key universities
Key Universities involved in SSIS are: the London School of Economics (LSE), Lancaster University, University of Manchester, University of Warwick, the Massachusetts Institute of Technology (MIT), University of Salford, Case Western Reserve University, the University of Cambridge, University of Edinburgh, Harvard University, and Peking University.
Key people
High profile people in the field are Claudio Ciborra, Jannis Kallinikos, Chrisanthi Avgerou & Susan Scott, Tony Cornford (LSE), Wanda Orlikowski (MIT), Shoshana Zuboff (Harvard), Lucas Introna & Lucy Suchman (Lancaster), Joe Nandhakumar (Warwick), Wendy Currie (Greenwich), Geoff Walsham, Mathew Jones & Michael Barrett (Cambridge), Richard Boland & Kalle Lyytinen (Case Western), Rob Kling (Indiana).
Key publications
Quast, M., Handel, M. J., Favre, J.-M., Estublier, J. (2013) Social Information Systems : Agility Without Chaos, Enterprise Information Systems, Springer.
Walsham, G. (1993) Interpreting information systems in organizations, John Wiley, Chichester.
Zuboff, S. (1988) In the age of the smart machine: The future of work and power, Heinemann Professional, Oxford.
See also
Formative context
References
WJ Orlikowski, JJ Baroudi (1991) 'Studying Information Technology in Organizations: Research Approaches and Assumptions', Information Systems Research, 1991
Avgerou C, (2000) βInformation systems: what sort of science is it?β Omega, vol 28, pp 567β579
External links
http://ccs.mit.edu/Wanda.html
http://www.lse.ac.uk/collections/informationSystems/research/researchFoci/Default.htm
Information systems | Social Study of Information Systems | [
"Technology"
] | 457 | [
"Information systems",
"Information technology"
] |
4,239,318 | https://en.wikipedia.org/wiki/Particular%20values%20of%20the%20gamma%20function | The gamma function is an important special function in mathematics. Its particular values can be expressed in closed form for integer and half-integer arguments, but no simple expressions are known for the values at rational points in general. Other fractional arguments can be approximated through efficient infinite products, infinite series, and recurrence relations.
Integers and half-integers
For positive integer arguments, the gamma function coincides with the factorial. That is,
and hence
and so on. For non-positive integers, the gamma function is not defined.
For positive half-integers, the function values are given exactly by
or equivalently, for non-negative integer values ofΒ :
where denotes the double factorial. In particular,
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and by means of the reflection formula,
{|
|-
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General rational argument
In analogy with the half-integer formula,
where denotes the th multifactorial of . Numerically,
.
As tends to infinity,
where is the EulerβMascheroni constant and denotes asymptotic equivalence.
It is unknown whether these constants are transcendental in general, but and were shown to be transcendental by G. V. Chudnovsky. has also long been known to be transcendental, and Yuri Nesterenko proved in 1996 that , , and are algebraically independent.
For Β at least one of the two numbersΒ and Β is transcendental.
The number is related to the lemniscate constant by
Borwein and Zucker have found that can be expressed algebraically in terms of , , , , and where is a complete elliptic integral of the first kind. This permits efficiently approximating the gamma function of rational arguments to high precision using quadratically convergent arithmeticβgeometric mean iterations. For example:
No similar relations are known for or other denominators.
In particular, where AGM() is the arithmeticβgeometric mean, we have
Other formulas include the infinite products
and
where is the GlaisherβKinkelin constant and is Catalan's constant.
The following two representations for were given by I. MezΕ
and
where and are two of the Jacobi theta functions.
There also exist a number of Malmsten integrals for certain values of the gamma function:
Products
Some product identities include:
In general:
From those products can be deduced other values, for example, from the former equations for , and , can be deduced:
Other rational relations include
and many more relations for where the denominator d divides 24 or 60.
Gamma quotients with algebraic values must be "poised" in the sense that the sum of arguments is the same (modulo 1) for the denominator and the numerator.
A more sophisticated example:
Imaginary and complex arguments
The gamma function at the imaginary unit gives , :
It may also be given in terms of the Barnes -function:
Curiously enough, appears in the below integral evaluation:
Here denotes the fractional part.
Because of the Euler Reflection Formula, and the fact that , we have an expression for the modulus squared of the Gamma function evaluated on the imaginary axis:
The above integral therefore relates to the phase of .
The gamma function with other complex arguments returns
Other constants
The gamma function has a local minimum on the positive real axis
with the value
.
Integrating the reciprocal gamma function along the positive real axis also gives the FransΓ©nβRobinson constant.
On the negative real axis, the first local maxima and minima (zeros of the digamma function) are:
See also
ChowlaβSelberg formula
References
Further reading
X. Gourdon & P. Sebah. Introduction to the Gamma Function
Gamma and related functions
Mathematical constants | Particular values of the gamma function | [
"Mathematics"
] | 791 | [
"Mathematical constants",
"Mathematical objects",
"Numbers",
"nan"
] |
4,239,505 | https://en.wikipedia.org/wiki/Ethernet%20extender | An Ethernet extender (also network extender or LAN extender) is any device used to extend an Ethernet or network segment beyond its inherent distance limitation which is approximately for most common forms of twisted pair Ethernet. These devices employ a variety of transmission technologies and physical media (wireless, copper wire, fiber-optic cable, coaxial cable).
The extender forwards traffic between LANs transparent to higher network-layer protocols over distances that far exceed the limitations of standard Ethernet.
Options
Extenders that use copper wire include 2- and 4-wire variants using unconditioned copper wiring to extend a LAN. Network extenders use various methods (line encodings), such as TC-PAM, 2B1Q or DMT, to transmit information. While transmitting over copper wire does not allow for the speeds that fiber-optic transmission does, it allows the use of existing voice-grade copper or CCTV coaxial cable wiring. Copper-based Ethernet extenders must be used on unconditioned wire (without load coils), such as unused twisted pairs and alarm circuits.
Connecting a private LAN between buildings or more distant locations is a challenge. Wi-Fi requires a clear line-of-sight, special antennas, and is subject to weather. If the buildings are within 100m, a normal Ethernet cable segment can be used, with due consideration of potential grounding problems between the locations. Up to 200m, it may be possible to set up an ordinary Ethernet bridge or router in the middle, if power and weather protection can be arranged.
Fiber optic connection is ideal, allowing connections of over a km and high speeds with no electrical shock or surge issues, but is technically specialized and expensive for both the end equipment interfaces and the cable. Damage to the cable requires special skills to repair or total replacement.
Specialized equipment can inter-connect two LANs over a single twisted pair of wires, such as the Moxa IEX Series, Cisco LRE (Long Reach Ethernet), Enable-IT Ethernet Extender Experts VDSL2, Patton CopperLink or EtherWAN Ethernet Extenders using VDSL technology. Distances of 300Β m (1000Β feet) at 50Β Mbit/s up to at 128Β kbit/s is possible. Westermo DDW products are capable of 10 miles at 30.3Β Mbit/s using SHDSL technology. Coaxial cable are often permitting higher speeds and larger distances than twisted pair wires. The equipment is mostly simple to operate, and the connection wire is common, cheap and maintainable.
Ordinary ADSL modems cannot be connected back-to-back, because the ATU-R (ADSL Termination Unit - Remote) units that are used by customers require specialized ATU-C (Central Office) support provided by phone company equipment, usually by a complex and expensive DSLAM (DSL access multiplexer). However some symmetric digital subscriber line (SDSL) modems such as the SpeedStream 5851 can be connected back-to-back, allowing upload and download speeds of about 2Β Mbit/s over substantial distances, using a simple twisted pair of wires.
Back-to-back operation may also be possible with single-pair high-speed digital subscriber line (G.SHDSL) modems.
Similar technologies were standardized as Ethernet in the first mile:
2BASE-TL Full-duplex long reach point-to-point link over voice-grade copper wiring. 2BASE-TL PHY can deliver a minimum of 2 Mbit/s and a maximum of 5.69 Mbit/s over distances of up to 2700 m (9,000Β ft), using ITU-T G.991.2 (G.SHDSL.bis) technology over a single copper pair.
10PASS-TS Full-duplex short reach Point-to-Point link over voice-grade copper wiring. 10PASS-TS PHY can deliver a minimum of 10Β Mbit/s over distances of up to 750Β m (2460Β ft), using ITU-T G.993.1 (VDSL) technology over a single copper pair.
References
Local loop
Extender | Ethernet extender | [
"Technology"
] | 860 | [
"Computing stubs",
"Computer network stubs"
] |
4,239,889 | https://en.wikipedia.org/wiki/Thomas%20Carell | Thomas Carell (born 1966) is a German biochemist.
Early life and education
Carell was born in 1966 in Herford Germany, he studied chemistry from 1985 till 1990 at the University of MΓΌnster finishing with a diploma thesis at the Max Planck Institute for Medical Research Heidelberg. After his PhD thesis on Porphyrin chemistry at the same institute, he did his postdoctoral at the Massachusetts Institute of Technology in 1993.
He finished his habilitation on DNA repair proteins at the EidgenΓΆssischen Technischen Hochschule ZΓΌrich in 1998.
Career
From 2000 till 2004 he was Professor for organic chemistry at the University of Marburg until he became Professor for organic chemistry at the Ludwig Maximilian University of Munich. His main interest is still the DNA repair system.
Awards and honors
In 2004, he received the Gottfried Wilhelm Leibniz Prize of the Deutsche Forschungsgemeinschaft, which is the highest honour awarded in German research. In 2008, he was awarded the for his work on the DNA repair systems. In 2008 he became a member of the German Academy of Sciences Leopoldina.
Since 2010, Professor Carell has been an Associate Editor of Chemical Science, the flagship general chemistry journal published by the Royal Society of Chemistry
References
External links
Portrait at the Deutschen Forschungs Gesellschaft
Homepage at the LMU Munich
Interview with Thomas Carell on the website of the Royal Society of Chemistry.
Carell, Thomas
Carell, Thomas
Carell, Thomas
Carell, Thomas
University of MΓΌnster alumni
Massachusetts Institute of Technology alumni
Academic staff of the Ludwig Maximilian University of Munich
People from Herford
Gottfried Wilhelm Leibniz Prize winners
Members of the German National Academy of Sciences Leopoldina | Thomas Carell | [
"Chemistry"
] | 337 | [
"Biochemistry stubs",
"Biochemists",
"Biochemist stubs"
] |
4,240,032 | https://en.wikipedia.org/wiki/Solenoid%20voltmeter | A solenoid voltmeter is a specific type of voltmeter electricians use to test electrical power circuits. It uses a solenoid coil to attract a spring-loaded plunger; the movement of the plunger is calibrated in terms of approximate voltage. It is more rugged than a D'arsonval movement, but neither as sensitive nor as precise.
Wiggy is the registered trademark for a common solenoid voltmeter used in North America derived from a device patent assigned to the Wigginton Company, US patent number 1,538,906.
Operation
Rather than using a D'Arsonval movement or digital electronics, the solenoid voltmeter simply uses a spring-loaded solenoid carrying a pointer (it might also be described as a form of moving iron meter). Greater voltage creates more magnetism pulling the solenoid's core in further against the spring loading, moving the pointer. A short scale converts the pointer's movement into the voltage reading. Solenoid voltmeters usually have a scale on each side of the pointer; one is calibrated for alternating current and one is calibrated for direct current. Only one "range" is provided and it usually extends from zero to about 600 volts.
A small permanent magnet rotor is usually mounted at the top of the meter. For DC, this magnet flips one way or the other, indicating by the exposed color (red or black) which lead is connected to positive. For AC, the rotor simply vibrates, indicating that the meter is connected to an AC circuit. Another form of tester uses a miniature neon lamp; the negative electrode glows, indicating polarity on DC circuits, or both electrodes glow, indicating AC.
Models made by some manufacturers include continuity test lights, which are energized by a battery within the tester. This is particularly advantageous when testing, for example, fuses in live circuits, since no switching is required to change from continuity mode to voltage detecting mode.
Comparison with moving coil meters
Solenoid voltmeters are extremely rugged and not very susceptible to damage through either rough handling or electrical overload, compared with more delicate but more precise instruments of the moving-coil D'arsonval type
For "go/no go" testing, there is no need to read the scale as application of AC power creates a perceivable vibration and sound within the meter. This feature makes the tester very handy in noisy, poorly illuminated, or very bright surroundings. The meter can be felt, the more it jumps the higher the voltage.
Solenoid voltmeters draw appreciable current in operation. When testing power supply circuits, a high-impedance connection (that is, a nearly open-circuit fault such as a burned switch contact or wire joint) in the power path might still allow enough voltage/current through to register on a high-impedance digital voltmeter, but it probably can't actuate the solenoid voltmeter. For use with high impedance circuit applications, however, they are not so good, as they draw appreciable current and therefore alter the voltage being measured. They can be used to test residual-current devices (GFCIs) because the current drawn trips most RCDs when the solenoid voltmeter is connected between the live and earth conductors.
Some manufacturers include a continuity test lamp function in a solenoid meter; these use the same probes as the voltage test function. This feature is useful when testing the status of contacts in energized circuits. The continuity light displays if the contact is closed, and the solenoid voltmeter shows voltage presence if open (and energized).
In contrast to multimeters, solenoid voltmeters have no other built-in functions (such as the ability to act as an ammeter, ohmmeter, or capacitance meter); they are just simple, easy-to-use power voltmeters. Solenoid voltmeters are useless on low-voltage circuits (for example, 12 volt circuits). The basic range of the voltmeter starts at around 90V (AC or DC).
Solenoid voltmeters are not precise. For example, there would be no reliably perceptible difference in the reading between 220 VAC and 240 VAC.
They are meant for intermittent operation. They draw a moderate amount of power from the circuit under test and can overheat if used for continuous monitoring.
The low impedance and low sensitivity of the tester may not show high-impedance connections to a voltage source, which can still source enough current to cause a shock hazard.
See also
Test light
Continuity tester
References
External links
All About Wiggy
Voltmeters
Electrical test equipment | Solenoid voltmeter | [
"Physics",
"Technology",
"Engineering"
] | 1,000 | [
"Voltmeters",
"Physical quantities",
"Electrical test equipment",
"Measuring instruments",
"Voltage"
] |
4,240,179 | https://en.wikipedia.org/wiki/Reinecke%27s%20salt | Reinecke's salt is an inorganic compound with the formula NH4[Cr(NCS)4(NH3)2]Β·H2O. The dark-red crystalline compound is soluble in boiling water, acetone, and ethanol. It can be classified as a metal isothiocyanate complex.
Structure, preparation, reactions
The chromium atom is surrounded by six nitrogen atoms in an octahedral geometry. The NH3 ligands are mutually trans and the CrβNCS groups are linear. The salt crystallizes with one molecule of water.
It was first reported in 1863. NH4[Cr(NCS)4(NH3)2] is prepared by treatment of molten NH4SCN (melting point around 145β150Β Β°C) with (NH4)2Cr2O7.
This salt was once widely used to precipitate primary and secondary amines as their ammonium salts. Included in the amines that effectively form crystalline precipitates are those derived from the amino acids, including proline and hydroxyproline. It also reacts with Hg2+ compounds, giving a red color or a red precipitate.
References
Chromium complexes
Reagents for organic chemistry
Ammine complexes
Thiocyanates
Chromium(III) compounds
Ammonium compounds | Reinecke's salt | [
"Chemistry"
] | 275 | [
"Functional groups",
"Salts",
"Ammonium compounds",
"Reagents for organic chemistry",
"Thiocyanates"
] |
4,240,292 | https://en.wikipedia.org/wiki/Porphyra | Porphyra is a genus of coldwater seaweeds that grow in cold, shallow seawater. More specifically, it belongs to red algae phylum of laver species (from which comes laverbread), comprising approximately 70 species. It grows in the intertidal zone, typically between the upper intertidal zone and the splash zone in cold waters of temperate oceans. In East Asia, it is used to produce the sea vegetable products nori (in Japan) and gim (in Korea). There are considered to be 60β70 species of Porphyra worldwide and seven around Britain and Ireland, where it has been traditionally used to produce edible sea vegetables on the Irish Sea coast. The species Porphyra purpurea has one of the largest plastid genomes known, with 251 genes.
Life cycle
Porphyra displays a heteromorphic alternation of generations. The thallus we see is the haploid generation; it can reproduce asexually by forming spores which grow to replicate the original thallus. It can also reproduce sexually. Both male and female gametes are formed on the one thallus. The female gametes while still on the thallus are fertilized by the released male gametes, which are non-motile. The fertilized, now diploid, carposporangia after mitosis produce spores (carpospores) which settle, then bore into shells, germinate and form a filamentous stage. This stage was originally thought to be a different species of alga, and was referred to as Conchocelis rosea. That Conchocelis was the diploid stage of Porphyra was discovered in 1949 by the British phycologist Kathleen Mary Drew-Baker for the European species Porphyra umbilicalis. It was later shown for species from other regions as well.
Food
Most human cultures with access to use it as a food or somehow in the diet, making it perhaps the most domesticated of the marine algae, known as laver, (Vietnamese), nori (Japanese:), amanori (Japanese), zakai, gim (Korean:), zΗcΓ i (Chinese:), karengo, sloke or slukos. The marine red alga Porphyra has been cultivated extensively in many Asian countries as an edible seaweed used to wrap the rice and fish that compose the Japanese food sushi and the Korean food gimbap. In Japan, the annual production of Porphyra species is valued at 100 billion yen (US$1 billion).
is harvested from the coasts of Great Britain and Ireland, where it has a variety of culinary uses, including laverbread. In Hawaii, "the species is considered a delicacy, called ". Porphyra was also harvested by the Southern Kwakiutl, Haida, Seechelt, Squawmish, Nuu-chah-nulth, Nuxalk, Tsimshian, and Tlingit peoples of the North American Pacific coast.
Vitamin B12
Porphyra contains vitamin B12 and one study suggests that it is the most suitable non-meat source of this essential vitamin. In the view of the Academy of Nutrition and Dietetics, however, it may not provide an adequate source of B12 for vegans.
Species
Porphyra currently contains 57 confirmed species and 14 unconfirmed species.
Confirmed
Unconfirmed
Following a major reassessment of the genus in 2011, many species previously included in Porphyra have been transferred to Pyropia: for example Pyropia tenera, Pyropia yezoensis, and the species from New Zealand Pyropia rakiura and Pyropia virididentata, leaving only five species out of seventy still within Porphyra itself.
See also
Green laver
References
External links
Video footage of Laverbread or Bara Lawr
Red algae genera
Bangiophyceae
Edible seaweeds
Seaweeds
Edible algae
Taxa named by Carl Adolph Agardh | Porphyra | [
"Biology"
] | 840 | [
"Seaweeds",
"Algae",
"Edible algae"
] |
4,240,330 | https://en.wikipedia.org/wiki/Current%20ratio | The current ratio is an liquidity ratio that measures whether a firm has enough resources to meet its short-term obligations. It is the ratio of a firm's current assets to its current liabilities, .
The current ratio is an indication of a firm's accounting liquidity. Acceptable current ratios vary across industries. Generally, high current ratio are regarded as better than low current ratios, as an indication of whether a company can pay a creditor back. However, if a company's current ratio is too high, it may indicate that the company is not efficiently using its current assets.
A current ratio of less than 1 indicates that the company may have problems meeting its short-term obligations. However, if inventory turns into cash much more rapidly than the accounts payable become due, then the firm's current ratio can comfortably remain less than one. Low current ratios can also be justified for businesses that can collect cash from customers long before they need to pay their suppliers.
To determine liquidity, the quick ratio is also used, which excludes current assets that may not be easily liquidated, like prepaid expenses and inventory.
See also
Debt ratio
Quick ratio
Ratio
References
Financial ratios
Working capital management | Current ratio | [
"Mathematics"
] | 243 | [
"Financial ratios",
"Quantity",
"Metrics"
] |
4,240,516 | https://en.wikipedia.org/wiki/National%20Information%20Assurance%20Certification%20and%20Accreditation%20Process | The National Information Assurance Certification and Accreditation Process (NIACAP) formerly was the minimum-standard process for the certification and accreditation of computer and telecommunications systems that handle U.S. national-security information. NIACAP was derived from the Department of Defense Certification and Accreditation Process (DITSCAP), and it played a key role in the National Information Assurance Partnership.
The Committee on National Security Systems (CNSS) Policy (CNSSP) No. 22 dated January 2012 cancelled CNSS Policy No. 6, βNational Policy on Certification and Accreditation of National Security Systems,β dated October 2005, and National Security Telecommunications and Information Systems Security Instruction (NSTISSI) 1000, βNational Information Assurance Certification and Accreditation Process (NIACAP),β dated April 2000. CNSSP No. 22 also states that "The CNSS intends to adopt National Institute of Standards and Technology (NIST) issuances where applicable. Additional CNSS issuances will occur only when the needs of NSS are not sufficiently addressed in a NIST document. Annex B identifies the guidance documents, which includes NIST Special Publications (SP), for establishing an organization-wide risk management program." It directs the organization to make use of NIST Special Publication 800-37, which implies that the Risk management framework (RMF) STEP 6 β AUTHORIZE INFORMATION SYSTEM replaces the Certification and Accreditation process for National Security Systems, just as it did for all other areas of the Federal government who fall under SP 800-37 Rev. 1.
References
Computer security accreditations
United States Department of Defense | National Information Assurance Certification and Accreditation Process | [
"Technology"
] | 321 | [
"Computer security stubs",
"Computing stubs"
] |
4,240,766 | https://en.wikipedia.org/wiki/Upland%20and%20lowland | Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland.
Definitions
Upland and lowland are portions of a plain that are conditionally categorized by their elevation above the sea level. Lowlands are usually no higher than , while uplands are somewhere around to . On unusual occasions, certain lowlands such as the Caspian Depression lie below sea level. Uplands areas tend to spike into valleys and mountains, forming mountain ranges while lowland areas tend to be uniformly flat, although both can vary such as the Mongolian Plateau.
Upland habitats are cold, clear and rocky whose rivers are fast-flowing in mountainous areas; lowland habitats are warm with slow-flowing rivers found in relatively flat lowland areas, with water that is frequently colored by sediment and organic matter.
These classifications overlap with the geological definitions of "upland" and "lowland". In geology an "upland" is generally considered to be land that is at a higher elevation than the alluvial plain or stream terrace, which are considered to be "lowlands". The term "bottomland" refers to low-lying alluvial land near a river.
Much freshwater fish and invertebrate communities around the world show a pattern of specialization into upland or lowland river habitats. Classifying rivers and streams as upland or lowland is important in freshwater ecology, as the two types of river habitat are very different, and usually support very different populations of fish and invertebrate species.
Uplands
In freshwater ecology, upland rivers and streams are the fast-flowing rivers and streams that drain elevated or mountainous country, often onto broad alluvial plains (where they become lowland rivers). However, elevation is not the sole determinant of whether a river is upland or lowland. Arguably the most important determinants are those of stream power and stream gradient. Rivers with a course that drops rapidly in elevation will have faster water flow and higher stream power or "force of water". This in turn produces the other characteristics of an upland riverβan incised course, a river bed dominated by bedrock and coarse sediments, a riffle and pool structure and cooler water temperatures. Rivers with a course that drops in elevation very slowly will have slower water flow and lower force. This in turn produces the other characteristics of a lowland riverβa meandering course lacking rapids, a river bed dominated by fine sediments and higher water temperatures. Lowland rivers tend to carry more suspended sediment and organic matter as well, but some lowland rivers have periods of high water clarity in seasonal low-flow periods.
The generally clear, cool, fast-flowing waters and bedrock and coarse sediment beds of upland rivers encourage fish species with limited temperature tolerances, high oxygen needs, strong swimming ability and specialised reproductive strategies to prevent eggs or larvae being swept away. These characteristics also encourage invertebrate species with limited temperature tolerances, high oxygen needs and ecologies revolving around coarse sediments and interstices or "gaps" between those coarse sediments.
The term "upland" is also used in wetland ecology, where "upland" plants indicate an area that is not a wetland.
Lowlands
The generally more turbid, warm, slow-flowing waters and fine sediment beds of lowland rivers encourage fish species with broad temperature tolerances and greater tolerances to low oxygen levels, and life history and breeding strategies adapted to these and other traits of lowland rivers. These characteristics also encourage invertebrate species with broad temperature tolerances and greater tolerances to low oxygen levels and ecologies revolving around fine sediments or alternative habitats such as submerged woody debris ("snags") or submergent macrophytes ("water weed").
Lowland alluvial plains
Lowland alluvial plains form when there is deposition of sediment over a long period of time by one or more rivers coming from highland regions, and then are deposited in lowland regions for long periods of time. Examples include American Bottom, a flood plain of the Mississippi River in Southern Illinois, Bois Brule Bottom, and Bottomland hardwood forest a deciduous hardwood forest found in broad lowland floodplains of the United States.
See also
Freshwater biology
Highland
Mountain river
River reclamation
Riparian zone
Plateau
References
Freshwater ecology
Water and the environment
Riparian zone
Rivers | Upland and lowland | [
"Environmental_science"
] | 860 | [
"Riparian zone",
"Hydrology"
] |
4,240,854 | https://en.wikipedia.org/wiki/Bipolaron | In physics, a bipolaron is a type of quasiparticle consisting of two polarons. In organic chemistry, it is a molecule or a part of a macromolecular chain containing two positive charges in a conjugated system.
Bipolarons in physics
In physics, a bipolaron is a bound pair of two polarons. An electron in a material may cause a distortion in the underlying lattice. The combination of electron and distortion (which may also be understood as a cloud of phonons) is known as a polaron (in part because the interaction between electron and lattice is via a polarization). When two polarons are close together, they can lower their energy by sharing the same distortions, which leads to an effective attraction between the polarons. If the interaction is sufficiently large, then that attraction leads to a bound bipolaron. For strong attraction, bipolarons may be small. Small bipolarons have integer spin and thus share some of the properties of bosons. If many bipolarons form without coming too close, they might be able to form a BoseβEinstein condensate. This has led to a suggestion that bipolarons could be a possible mechanism for high-temperature superconductivity. For example, they can lead to a very direct interpretation of the isotope effect.
Recently, bipolarons were predicted theorethically in a Bose-Einstein condensate. Two polarons interchange sound waves and they attract to each other, forming a bound-state when the strength coupling between the single polarons and the condensate is strong in comparison with the interactions of the host gas.
Bipolarons in organic chemistry
In organic chemistry, a bipolaron is a molecule or part of a macromolecular chain containing two positive charges in a conjugated system. The charges can be located in the centre of the chain or at its termini. Bipolarons and polarons are encountered in doped conducting polymers such as polythiophene.
It is possible to synthesize and isolate bipolaron model compounds for X-ray diffraction studies. The diamagnetic bis(triaryl)amine dication 2 in scheme 1 is prepared from the neutral precursor 1 in dichloromethane by reaction with 4 equivalents of antimony pentachloride. Two resonance structures exist for the dication. Structure 2a is a (singlet) diradical and 2b is the closed shell quinoid. The experimental bond lengths for the central vinylidene group in 2 are 141 pm and 137 pm compared to 144 pm and 134 pm for the precursor 1 implying some contribution from the quinoid structure.
On the other hand, when a thiophene unit is added to the core in the structure depicted in scheme 2, these bond lengths are identical (around 138 pm) making it a true hybrid.
See also
Quinonoid zwitterions
References
Ions
Quasiparticles | Bipolaron | [
"Physics",
"Materials_science"
] | 598 | [
"Quasiparticles",
"Subatomic particles",
"Condensed matter physics",
"Matter"
] |
4,240,861 | https://en.wikipedia.org/wiki/Quinoid | In organic chemistry, quinoids are a class of chemical compounds that are derived from quinone. Unlike benzenoid structures, the quinoid part is not aromatic.
See also
Benzenoid
Aromatic compound
References
Cyclic compounds | Quinoid | [
"Chemistry"
] | 48 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
4,240,997 | https://en.wikipedia.org/wiki/Octet%20%28computing%29 | The octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as the byte has historically been used for storage units of a variety of sizes.
The term octad(e) for eight bits is no longer common.
Definition
The international standard IEC 60027-2, chapterΒ 3.8.2, states that a byte is an octet of bits. However, the unit byte has historically been platform-dependent and has represented various storage sizes in the history of computing. Due to the influence of several major computer architectures and product lines, the byte became overwhelmingly associated with eightΒ bits. This meaning of byte is codified in such standards as ISO/IEC 80000-13. While byte and octet are often used synonymously, those working with certain legacy systems are careful to avoid ambiguity.
Octets can be represented using number systems of varying bases such as the hexadecimal, decimal, or octal number systems. The binary value of all eight bits set (or activated) is , equal to the hexadecimal value , the decimal valueΒ , and the octal valueΒ . One octet can be used to represent decimal values ranging from 0 to 255.
The term octet (symbol: o) is often used when the use of byte might be ambiguous. It is frequently used in the Request for Comments (RFC) publications of the Internet Engineering Task Force to describe storage sizes of network protocol parameters. The earliest example is from 1974. In 2000, Bob Bemer claimed to have earlier proposed the usage of the term octet for "8-bit bytes" when he headed software operations for Cie. Bull in France in 1965 to 1966.
In France, French Canada and Romania, octet is used in common language instead of byte when the eight-bit sense is required; for example, a megabyte (MB) is termed a megaoctet (Mo).
A variable-length sequence of octets, as in Abstract Syntax Notation One (ASN.1), is referred to as an octet string.
Octad
Historically, in Western Europe, the term octad (or octade) was used to specifically denote eight bits, a usage no longer common. Early examples of usage exist in British, Dutch and German sources of the 1960s and 1970s, and throughout the documentation of Philips mainframe computers. Similar terms are triad for a grouping of three bits and decade for ten bits.
Unit multiples
Unit multiples of the octet may be formed with SI prefixes and binary prefixes (power of 2 prefixes) as standardized by the International Electrotechnical Commission in 1998.
Use in Internet Protocol addresses
The octet is used in representations of Internet Protocol computer network addresses.
An IPv4 address consists of four octets, usually displayed individually as a series of decimal values ranging from 0 to 255, each separated by a full stop (dot). Using octets with all eight bits set, the representation of the highest-numbered IPv4 address is .
An IPv6 address consists of sixteen octets, displayed in hexadecimal representation (two hexits per octet), using a colon character (:) after each pair of octets (16 bits are also known as hextet) for readability, such as .
See also
Variable-width encoding
Notes
References
External links
Units of information | Octet (computing) | [
"Mathematics"
] | 700 | [
"Units of information",
"Quantity",
"Units of measurement"
] |
4,241,261 | https://en.wikipedia.org/wiki/SolarWorld | SolarWorld is a German company dedicated to the manufacture and marketing of photovoltaic products worldwide by integrating all components of the solar value chain, from feedstock (polysilicon) to module production, from trade with solar panels to the promotion and construction of turn-key solar power systems. The group controls the development of solar power technologies at all levels in-house.
SolarWorld AG is listed on the Frankfurt Stock Exchange, the Photovoltaik Global 30 Index and the ΓkoDAX.
In May 2017, wholly owned subsidiary SolarWorld Americas, based in Oregon, US, joined fellow American solar panel manufacturer Suniva in its Section 201 trade action to request relief from what it claimed are unfair practices from solar panel importers to the United States. The requested remedy was a tariff on imported solar panels. FirstSolar, the largest US solar panel manufacturer, joined the action on October 10, 2017, while the Solar Energy Industry Association (the major American solar trade association) was leading the opposition to the tariff requests.
The company filed for insolvency of its German subsidiaries alone in May 2017. While subsidiary SolarWorld America was not itself insolvent, it subsequently was put up for sale or other action to help resolve the debts of the German parent company. In the beginning of August 2017, leaving all liabilities behind, all the assets alone were acquired by the original Founder of SolarWorld Ag, Frank Asbeck along with Qatar Solar Technologies (QSTec) to form SolarWorld Industries GmbH, thus becoming completely debt-free and the only Solar Manufacturer in the world with zero-debt and zero liability. According to the Press Release issued by SolarWorld Industries GmbH, it will now have just 500 employees, drastically down from earlier, thus cutting costs. According to the company, the company will continue its transition to mono PERC-only cells production. The new entity, SolarWorld Industries GmbH takes over the production facilities and distribution businesses in Europe, Asia and Africa. "We plan to start with a production capacity of 700 MW, which can also be boosted to the previous capacity of more than 1GW. At launch, the company will have 515 employees. Of these, more than 12% are employed in research and more than 5% are trainees,β he said adding that the new company had already signed a 25MW order, without giving further details.
The newly founded SolarWorld Industries GmbH filed for insolvency again in March 2018. In June 2018 the regional public TV station MDR reported, that most of SolarWorlds production workers have been transferred into other forms of employment and production will be closed by end of September.
More than two years after the insolvency, the Solarworld factory in Freiberg gets a new opportunity. The buildings are sold for around twelve million euros to the new owner. The Swiss company Meyer Burger wants to produce solar cells in Freiberg and Bitterfeld-Wolfen. The production is expected to start in the first half of 2021.
History
SolarWorld was founded in 1988 as individual company by engineer and chief executive officer Frank Asbeck, and engaged in projects to produce renewable energy. In 1998, these activities were transferred to the newly founded SolarWorld AG, which went public on 11 August 1999.
In 2006 Shell divested its crystalline silicon solar business activities to SolarWorld.
SolarWorld has received German Sustainability Award in the category of "Germanyβs Most Sustainable Production 2008".
Since 2010 the company has a joint venture with Qatar Solar Technologies (QSTec). Due to a financial crisis, Solarworld was restructured and QSTec became the largest shareholder in 2013.
In 2012, Washington, D.C.βbased law firm, Wiley Rein, was hacked. According to Bloomberg News, the hackers wanted information about the German manufacturer SolarWorld. SolarWorld's computers were hacked about the same time.
In 2016, SolarWorld started βgraduallyβ migrating cell production to PERC and five busbar technology. At the core of SolarWorld's high-tech strategy is migrating all solar cell production to PERC (Passivated Emitter Rear Cell) technology and moving from three busbars to five in order to boost conversion efficiencies and limit capital expenditures at the same time as these changes are relatively simple and low-risk ramps, compared to entire new cell concepts such as heterojunction, according to Neuhaus at PV CellTech. SolarWorld's PV CellTech presentation also revealed that average efficiencies of PERC cells in high-volume production had achieved 21.4%, resulting in PV module power distribution average of 303.3W. SolarWorld has also developed a bi-facial version of its current PERC cell that has entered production and more capacity is expected to be allocated to bi-facial cells and modules.
On May 10, 2017, SolarWorld AG filed for insolvency citing βongoing price distortionsβ and βno longer a positive forecast for the futureβ. According to Mr. Piepenburg, the administrator, it is now of major importance to maintain business operations as smoothly as possible. In May 2016, a lawsuit brought by U.S. silicon supplier Hemlock was reported as "threatening the continued existence of the company" with damage claims up to $770 million.
The German facilities of SolarWorld were purchased by its founder Frank Asbeck in conjunction with Qatar Solar Technologies. Three days later, an appeals court upheld the verdict in the Hemlock case, resulting in SolarWorld AG being responsible to pay the damage claims.
SolarWorld Americas, the largest U.S. crystalline-silicon solar manufacturer for more than 42 years, is continuing to implement efficiencies and working with external partners to position the company for stabilization and a continued competitive position in the marketplace. Solarworld USA spokesman Ben Santarris said the company is sticking with the assumption of continuing normal operations, and continued to work with suppliers and customers to determine what the right size of the company should be going forward.
On August 18, 2017, however, news came that the German administrator of SolarWorld AG's bankruptcy had put SolarWorld Americas up for sale, though no potential buyers had been identified at that time. The US-based subsidiary, which reportedly produced half of "SolarWorld" branded modules worldwide, was put "in something of a limbo" by the bankruptcy and a spokesperson stated the company had entered an "open ended" mergers and acquisitions process.
Facilities
Within the SolarWorld Group many specialized workers were employed in the enterprise's units located in Bonn (headquarters), Freiberg, and Hillsboro, Oregon (US headquarters).
The business also had a manufacturing facility in Hillsboro, Oregon, purchased in 2007 from Japan's Komatsu Group.
In 2008, it was the largest solar cell manufacturing facility in North America. That factory was taken over by SunPower in October 2018, as part of SunPower's acquisition of SolarWorld Americas.
In 2013 SolarWorld took over production from Bosch Solar Energy in Arnstadt and continued to employ about 800 workers.
SolarWorld AG has sales offices in Germany, Spain, US, South Africa, UK and Singapore.
Grid parity
In 2010, SolarWorld called for lowering Germany's lucrative solar feed-in tariffs and its CEO, Frank Asbeck, supported a 10 percent to 15 percent drop for the incentives. In 2011, utility-scale solar power stations achieved grid parity for domestic consumers as guaranteed tariffs fell below retail electricity prices. Feed-in tariffs continued to drop well below the gross domestic electricity price. Since the beginning of 2012, newly installed, small rooftop PV system also have achieved grid parity. The current policy is to revise tariffs on a monthly basis reducing them by 1 percent unless actual deployment does not meet agreed upon targets. As of spring 2015, tariffs ranged from 8 to 12 euro-cents per kilowatt-hour depending on the PV system's size.
Vehicles
SolarWorld is the main sponsor of the SolarWorld No. 1 solar car developed by the FH Bochum SolarCar Team.
On November 19, 2008, SolarWorld AG announced a bid to buy German automaker Opel from General Motors. The bid was for 1 billion Euro, 250 million being paid in cash and 750 million being paid in bank credits. SolarWorld specified conditions such as Opel should be split from General Motors. Solarworld announced that it intends to create the first electric automotive OEM. However, GM rejected the bid saying "Opel is not for sale".
References
Further reading
European consortium mulls mega solar factory to outshine Chinese, Deutsche Welle website, May 20, 2014.
External links
SolarWorld USA website
Solar energy in Germany
Photovoltaics manufacturers
Manufacturing companies of Germany
Manufacturing companies established in 1988
Companies based in Bonn
German brands
Companies listed on the Frankfurt Stock Exchange | SolarWorld | [
"Engineering"
] | 1,793 | [
"Photovoltaics manufacturers",
"Engineering companies"
] |
4,242,000 | https://en.wikipedia.org/wiki/Power%20system%20protection | Power system protection is a branch of electrical power engineering that deals with the protection of electrical power systems from faults through the disconnection of faulted parts from the rest of the electrical network. The objective of a protection scheme is to keep the power system stable by isolating only the components that are under fault, whilst leaving as much of the network as possible in operation. The devices that are used to protect the power systems from faults are called protection devices.
Components
Protection systems usually comprise five components
Current and voltage transformers to step down the high voltages and currents of the electrical power system to convenient levels for the relays to deal with
Protective relays to sense the fault and initiate a trip, or disconnection, order
Circuit breakers or RCDs to open/close the system based on relay and autorecloser commands
Batteries to provide power in case of power disconnection in the system
Communication channels to allow analysis of current and voltage at remote terminals of a line and to allow remote tripping of equipment.
For parts of a distribution system, fuses are capable of both sensing and disconnecting faults.
Failures may occur in each part, such as insulation failure, fallen or broken transmission lines, incorrect operation of circuit breakers, short circuits and open circuits. Protection devices are installed with the aims of protection of assets and ensuring continued supply of energy.
Switchgear is a combination of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switches are safe to open under normal load current (some switches are not safe to operate under normal or abnormal conditions), while protective devices are safe to open under fault current. Very important equipment may have completely redundant and independent protective systems, while a minor branch distribution line may have very simple low-cost protection.
Types of protection
High-voltage transmission network
Protection of the transmission and distribution system serves two functions: protection of the plant and protection of the public (including employees). At a basic level, protection disconnects equipment that experiences an overload or a short to earth. Some items in substations such as transformers might require additional protection based on temperature or gas pressure, among others.
Generator sets
In a power plant, the protective relays are intended to prevent damage to alternators or to the transformers in case of abnormal conditions of operation, due to internal failures, as well as insulating failures or regulation malfunctions. Such failures are unusual, so the protective relays have to operate very rarely. If a protective relay fails to detect a fault, the resulting damage to the alternator or to the transformer might require costly equipment repairs or replacement, as well as income loss from the inability to produce and sell energy.
Overload and back-up for distance (overcurrent)
Overload protection requires a current transformer which simply measures the current in a circuit and compares it to the predetermined value. There are two types of overload protection: instantaneous overcurrent (IOC) and time overcurrent (TOC). Instantaneous overcurrent requires that the current exceeds a predetermined level for the circuit breaker to operate. Time overcurrent protection operates based on a current vs time curve. Based on this curve, if the measured current exceeds a given level for the preset amount of time, the circuit breaker or fuse will operate. The function of both types is explained in .
Earth fault/ground fault
Earth fault protection also requires current transformers and senses an imbalance in a three-phase circuit. Normally the three phase currents are in balance, i.e. roughly equal in magnitude. If one or two phases become connected to earth via a low impedance path, their magnitudes will increase dramatically, as will current imbalance. If this imbalance exceeds a pre-determined value, a circuit breaker should operate. Restricted earth fault protection is a type of earth fault protection which looks for earth fault between two sets of current transformers (hence restricted to that zone).
Distance (impedance relay)
Distance protection detects both voltage and current. A fault on a circuit will generally create a sag in the voltage level. If the ratio of voltage to current measured at the relay terminals, which equates to an impedance, lands within a predetermined level the circuit breaker will operate. This is useful for reasonably long lines, lines longer than 10 miles, because their operating characteristics are based on the line characteristics. This means that when a fault appears on the line the impedance setting in the relay is compared to the apparent impedance of the line from the relay terminals to the fault. If the relay setting is determined to be below the apparent impedance it is determined that the fault is within the zone of protection. When the transmission line length is too short, less than 10 miles, distance protection becomes more difficult to coordinate. In these instances the best choice of protection is current differential protection.
Back-up
The objective of protection is to remove only the affected portion of plant and nothing else. A circuit breaker or protection relay may fail to operate. In important systems, a failure of primary protection will usually result in the operation of back-up protection. Remote back-up protection will generally remove both the affected and unaffected items of plant to clear the fault. Local back-up protection will remove the affected items of the plant to clear the fault.
Low-voltage networks
The low-voltage network generally relies upon fuses or low-voltage circuit breakers to remove both overload and earth faults.
Cybersecurity
The bulk system which is a large interconnected electrical system including transmission and control system is experiencing new cybersecurity threats every day. (βElectric Grid Cybersecurity,β 2019). Most of these attacks are aiming the control systems in the grids. These control systems are connected to the internet and makes it easier for hackers to attack them. These attacks can cause damage to equipment and limit the utility professionals ability to control the system.
Coordination
Protective device coordination is the process of determining the "best fit" timing of current interruption when abnormal electrical conditions occur. The goal is to minimize an outage to the greatest extent possible. Historically, protective device coordination was done on translucent logβlog paper. Modern methods normally include detailed computer based analysis and reporting.
Protection coordination is also handled through dividing the power system into protective zones. If a fault were to occur in a given zone, necessary actions will be executed to isolate that zone from the entire system. Zone definitions account for generators, buses, transformers, transmission and distribution lines, and motors. Additionally, zones possess the following features: zones overlap, overlap regions denote circuit breakers, and all circuit breakers in a given zone with a fault will open in order to isolate the fault. Overlapped regions are created by two sets of instrument transformers and relays for each circuit breaker. They are designed for redundancy to eliminate unprotected areas; however, overlapped regions are devised to remain as small as possible such that when a fault occurs in an overlap region and the two zones which encompass the fault are isolated, the sector of the power system which is lost from service is still small despite two zones being isolated.
Disturbance-monitoring equipment
Disturbance-monitoring equipment (DME) monitors and records system data pertaining to a fault. DME accomplish three main purposes:
model validation,
disturbance investigation, and
assessment of system protection performance.
DME devices include:
Sequence of event recorders, which record equipment response to the event
Fault recorders, which record actual waveform data of the system primary voltages and currents
Dynamic disturbance recorders (DDRs), which record incidents that portray power system behavior during dynamic events such as low frequency (0.1Β Hz β 3Β Hz) oscillations and abnormal frequency or voltage excursions
Performance measures
Protection engineers define dependability as the tendency of the protection system to operate correctly for in-zone faults. They define security as the tendency not to operate for out-of-zone faults. Both dependability and security are reliability issues. Fault tree analysis is one tool with which a protection engineer can compare the relative reliability of proposed protection schemes. Quantifying protection reliability is important for making the best decisions on improving a protection system, managing dependability versus security tradeoffs, and getting the best results for the least money. A quantitative understanding is essential in the competitive utility industry.
Reliability: Devices must function consistently when fault conditions occur, regardless of possibly being idle for months or years. Without this reliability, systems may cause costly damages.
Selectivity: Devices must avoid unwarranted, false trips.
Speed: Devices must function quickly to reduce equipment damage and fault duration, with only very precise intentional time delays.
Sensitivity: Devices must detect even the smallest value of faults and respond.
Economy: Devices must provide maximum protection at minimum cost.
Simplicity: Devices must minimize protection circuitry and equipment.
Reliability: Dependability vs Security
There are two aspects of reliable operation of protection systems: dependability and security. Dependability is the ability of the protection system to operate when called upon to remove a faulted element from the power system. Security is the ability of the protection system to restrain itself from operating during an external fault. Choosing the appropriate balance between security and dependability in designing the protection system requires engineering judgement and varies on a case-by-case basis.
See also
Fault current limiter
Network analyzer (AC power)
Prospective short-circuit current
ANSI device numbers
Notes
References
http://perso.numericable.fr/michlami protection and monitoring of the electrical energy transmission network
Over-current protection devices
Power engineering | Power system protection | [
"Engineering"
] | 1,954 | [
"Power engineering",
"Electrical engineering",
"Energy engineering"
] |
4,242,573 | https://en.wikipedia.org/wiki/Melzer%27s%20reagent | Melzer's reagent (also known as Melzer's iodine reagent, Melzer's solution or informally as Melzer's) is a chemical reagent used by mycologists to assist with the identification of fungi, and by phytopathologists for fungi that are plant pathogens.
Composition
Melzer's reagent is an aqueous solution of chloral hydrate, potassium iodide, and iodine. Depending on the formulation, it consists of approximately 2.50-3.75% potassium iodide and 0.75β1.25% iodine, with the remainder of the solution being 50% water and 50% chloral hydrate. Melzer's is toxic to humans if ingested due to the presence of iodine and chloral hydrate. Due to the legal status of chloral hydrate, Melzer's reagent is difficult to obtain in the United States.
In response to difficulties obtaining chloral hydrate, scientists at Rutgers formulated Visikol (compatible with Lugol's iodine) as a replacement. In 2019, research showed that Visikol behaves differently to Melzerβs reagent in several key situations, noting it should not be recommended as a viable substitute.
Melzer's reagent is part of a class of iodine/potassium iodide (IKI)-containing reagents used in biology; Lugol's iodine is another such formula.
Reactions
Melzer's is used by exposing fungal tissue or cells to the reagent, typically in a microscope slide preparation, and looking for any of three color reactions:
Amyloid or Melzer's-positive reaction, in which the material reacts blue to black.
Pseudoamyloid or dextrinoid reaction, in which the material reacts brown to reddish brown.
Inamyloid or Melzer's-negative, in which the tissues do not change color, or react faintly yellow-brown.
Among the amyloid reaction, two types can be distinguished:
Euamyloid reaction, in which the material turns blue without potassium hydroxide (KOH)-pretreatment.
Hemiamyloid reaction, in which the material turns red in Lugol's solution, but shows no reaction in Melzer's reagent; when KOH-pretreated it turns blue in both reagents (hemiamyloidity).
Melzer's reactions are typically almost immediate, though in some cases the reaction may take up to 20 minutes to develop.
The function of the chemicals that make up Melzer's reagent are several. The chloral hydrate is a clearing agent, bleaching and improving the transparency of various dark-colored microscopic materials. The potassium iodide is used to improve the solubility of the iodine, which is otherwise only semi-soluble in water. Iodine is thought to be the main active staining agent in Melzer's; it is thought to react with starch-like polysaccharides in the cell walls of amyloid material, however, its mechanism of action is not entirely understood. It has been observed that hemiamyloid material reacts differently when exposed to Melzer's than it does when exposed to other IKI solutions such as Lugol's, and that in some cases an amyloid reaction is shown in material that had prior exposure to KOH, but an inamyloid reaction without such pretreatment.
An experiment in which spores from 35 species of basidiomycetes were tested for reactions to both Melzer's and Lugol's showed that spores in a large percentage of the species tested display very different reactions between the two reagents. These varied from being weakly or non-reactive in Lugols, to giving iodine-positive reactions in Lugol's but not in Melzer's, to even giving dextrinoid reactions in Lugol's while giving amyloid reactions in Melzer's.
Melzer's degrades into a cloudy precipitate when combined with alkaline solutions, hence it cannot be used in combination or in direct series with such common mycological reagents such as potassium hydroxide or ammonium hydroxide solutions. When potassium hydroxide is used as a pretreatment, the alkalinity must be first neutralized before adding Melzer's.
History
The use of iodine-containing solutions as an aid to describing and identifying fungi dates back to the mid-19th century.
Melzer's reagent was first described in 1924 and takes its name from its inventor, the mycologist VΓ‘clav Melzer, who modified an older chloral hydrate-containing IKI solution developed by botanist Arthur Meyer. Melzer was a specialist in Russula, a genus in which the amyloidy on the spore ornamentation or entire spore is of great taxonomic significance.
References
Further reading
Blackwell M, et al. 2001. The presence of glycine betaine and the dextinoid reaction in basidiomata. Harvard Papers in Botany 6:35β41.
Rossman AY. 1980. The iodine reaction: Melzer's vs. IKI. MSA newsletter 31:22.
Mycology
Chemical tests
Analytical reagents | Melzer's reagent | [
"Chemistry",
"Biology"
] | 1,111 | [
"Mycology",
"Analytical reagents",
"Chemical tests"
] |
4,242,811 | https://en.wikipedia.org/wiki/Folsom%20Powerhouse%20State%20Historic%20Park | Folsom Powerhouse State Historic Park is a historical site preserving an 1895 alternating current (AC) hydroelectric power stationβone of the first in the United States.
Before the Folsom powerhouse was built nearly all electric power houses were using direct current (DC) generators powered by steam engines located within a very few miles of where the power was needed. The use of rushing water to generate hydroelectric power and then transmitting it long distances to where it could be used was not initially economically feasible as long as the electricity generated was low-voltage direct current. Once it was invented, AC power made it feasible to convert the electrical power to high voltage by using the newly invented transformers and to then economically transmit the power long distances to where it was needed. Lower voltage electrical power, which is much easier and safer to use, could be easily gotten by using transformers to convert the high voltage power to lower voltages near where it was being used. DC power cannot use a transformer to change its voltage. The Folsom Powerhouse, using part of the American River's rushing water to power its turbines connected to newly invented AC generators, generated three phase 60 cycle AC electricity (the same that's used today in the United States) that was boosted by newly invented transformers from 800 volts as generated to 11,000 volts and transmitted to Sacramento over a 22Β mi (35Β km)-long distribution line, one of the longest electrical distribution lines in the United States at the time.
Introduction
In Sacramento the 11,000 volts AC power was transformed down to a lower voltage near where it was needed for use. The Folsom Powerhouse was one of the first examples of significant electrical power being generated and economically shipped to where it could be used. Hydroelectric power had been demonstrated as a viable source of economical power despite being located a significant distances from the users. The Folsom Powerhouse is located above Sacramento on the American River in the city of Folsom.
History
The power station remained in operation until 1952 when the original Folsom dam across the American River was destroyed to make way for the new much larger Folsom Dam. The powerhouse was shut down after 57 years of continuous operation. Pacific Gas and Electric, who bought the original hydroelectric plant in 1902, donated the plant and most of its equipment to the State of California when the new Folsom Dam and hydroelectric plant was built. The State of California designated the site as California Historical Landmark Number #633. The historic park was established in 1956. The powerhouse was designated a U.S. National Historic Landmark in 1981. The two-story brick and granite Powerhouse looks much as it did in 1895. Its imposing generators, and the Tennessee marble-faced control switchboard stand as imposingly as they did more than a hundred years ago. Historic photos, interpretive exhibits and docent guided tours by the California State Park Service explain how the powerhouse worked. Some of the original water turbines, generators, etc. are still in place.
Before AC electric generators and the newly invented transformers were invented only DC electrical generators could be used to generate electrical power and they were restricted by their low voltage requirements to economically transmitting power for only a few miles. Too much power was lost in transmission at low voltage for long-distance power transmission to be practical. This meant the original power stations were restricted (at that time) to local steam generating plants built right in each local neighborhood. Pearl Street Station was the first central power plant in the United States. It was located at 255β257 Pearl Street in downtown Manhattan on a site measuring 50 by 100 feet (15 by 30 m), just south of Fulton Street. It began with one direct current generator powered by a coal burning steam engine, and it started generating electricity on September 4, 1882, serving an initial load of 400 incandescent lamps used by 85 customers located within about of the station.
However, with the advent of AC, there came the use of transformers to convert the generated power to a much higher voltage for transmission allowed the power plants and users to be separated by hundreds of miles if needed. The high voltage could then use transformers to obtain lower voltages for final use. Single point failures were minimized in the plant design. The AC generators and their associated water turbines were so large that they could not be shipped by rail and were shipped around Cape Horn by ship. Only two of the four alternating current generators were operating on July 13, 1895, when the powerhouse provided the first electricity to Sacramento via of transmission lines, making it one of the first places in the United States to transmit long-distance hydroelectric power. The Folsom power plant predates Niagara Falls Adams power House generating AC electrical transmission for local use and shipment to Buffalo, New York in 1897. The International Electro-Technical Exhibition - 1891 in Frankfurt am Main Germany demonstrated an earlier instance of long distance AC transmission of hydroelectric power. Westinghouse Electric Company and General Electric were in a race to develop better equipment and bring it to the United States.
Water supply
The water for the original Folsom hydroelectric plant was obtained from a diversion dam, long, wide at the top; wide at the bottom and tall, across the American River built in the 1890s.
The dam diverted a large stream of water into a long diversion canalβthe East Canal. This canal was wide and deep, carrying about of water per minute. The canal paralleled the river but sloped much less steeply gradually getting about above the river. The dam and canal were completed in 1893 under the direction of Horatio Gates Livermore who originally thought to use the power of the falling water to power a sawmill. Livermore utilized in part contracted prison labor from the nearby Folsom State Prison to help build the dam and canal. The geometry of the canal forebay and the American River gave the Folsom power plant a Hydraulic head of water of about (about was usable) before its water was discharged back into the American River. Initially only about of this hydraulic head was used. The water from the canal ended in a forebay where water borne debris was separated from the water and it was fed into four large penstocks and two smaller penstocks. All penstocks had water gates that could be closed to turn the water off on any turbine for maintenance. The AC generators, some of the largest designed and built up to that time, were powered via four penstocks full of rushing water driving four large turbines.
Turbines
The four large water turbines, some of the largest built up to that time, were made by S. Morgan Smith Works of York, Pennsylvania. There were two small penstocks plus turbines for the two DC generators.
Rushing water from the American River passing through four large water turbines powered the four AC generators and two more turbines powered smaller DC generators.
Governors
The four large turbines were connected directly to the alternating current generators and their speed controlled by adjusting the water flow, with a centrifugal governor, to obtain 300 shaft rpmβneeded to generate a steady 60 cycle current.
Alternators
The four alternating current generators are some of the most powerful rotating armature 3-phase machines ever built.
Newly invented by Elihu Thomson, they weighed almost 30 tons each (57,887 pounds) and were . These original AC generators used many DC generator components in their first design. The 750-kilowatt (1,005 horsepower) alternating current generators were made in the newly incorporated General Electric plant in Schenectady, New York.
The alternators had rotating armatures with 216 radial 4 inch slots formed into the perimeter. Each slot holds two insulated 3 1/2 foot rectangular inductive bars of related phase, an inner circle of 216 bars and an outside circle of 216 bars. The induction bars are twice bent into offsets in the same direction. The middle of the bar has a straight section 3 feet long, to get from the front of the rotor to the back. The inner circle of bars is connected to the outer circle by small conductive jumper blocks on the front and back of the rotor. The rotor's three phases are connected to six branch circuits. Each of the six branch circuits make their way three times progressively around the rotor in right hand flattened spirals.
Supplying power for the 24 stator (non-rotating) field coil magnets on the AC generators was a small direct current generator with another DC generator in standby mode for immediate substitution if needed. If one DC generator failed or needed maintenance the other one could be used.
All four AC generators power were connected to each other, when long-term demand increased and it was found that tying generators together improved frequency control, by synchronizing action.
Switch panel
To allow customers to use electric clocks regulated by synchronous motors, a Frequency "Indicator" was added to the Powerhouse switchboard.
To allow parallel alternators and power grid, a Synchroscope was added to the Switch Panel.
Transmission lines
The AC power generated (about 4,020 horse power or 3 MW) at the Folsom hydroelectric facility was converted to 11,000 volts at the power plant by twelve new (in 1895) air cooled transformers invented by William Stanley, Jr. and transmitted to Sacramento on twelve bare #1 AVG copper wires held by ceramic insulators that were attached to the cross beams mounted on two sets of cedar poles. The multiple wires allowed four independent three phase lines to be used. This allowed for repairs, maintenance and new installations without shutting the whole system down. The poles were planted about apart to string the power lines. Telephone lines were run beneath the power lines. Once in Sacramento the high voltage power was shipped near where it was going to be used and transformed down to a lower voltage for useβthe same as electrical power is shipped and used today. By 1895 almost 900 electric street railways and nearly 11,000 miles (18,000Β km) of track had been built in the United States and they were then one of the main users of electrical energy. Direct current electric motors, as used on electrical streetcars, were restricted in use to being only a few miles from the DC generators. DC power, despite its restrictions, had become very useful. A rotary converter, a type of motor generator, was used to convert alternating current (AC) to direct current (DC) for railway electrification from an AC power source. Factories were also heavy power users.
Transforming AC voltages up to high voltages for long-distance transmission and down to lower voltages at locations close to their use was a very attractive way to get access to a new source of power. Improvements in transformer design allowed the original air cooled transformers at the Folsom powerhouse to be replaced in 1900 with more efficient oil cooled transformers.
The alternating current electric induction motor was independently introduced in 1888 by Galileo Ferraris and Nikola Tesla, by 1895 was beginning to allow electrical power to replace steam as a power source. The induction motor allowed alternating current to be used directly without any conversions. The first heavy AC motor users were various factories which typically replaced their steam power plants. Alternating current electrical power and its easy conversion with transformers from low to high voltage and back to low voltage made possible the widespread electrical grids we routinely use today for a myriad of tasks.
On September 9, 1895, the new power provided by the powerhouse was celebrated in a "Grand Electric Carnival" decorating the Sacramento state capital with thousands of light bulbs to celebrate the 45th anniversary of California statehood.
Lower powerhouse
A second powerhouse was constructed below the original facility in 1897 to house an additional 750-kilowatt AC generator to meet the growing residential and public transit electricity demands of Sacramento. This generator was separated from the turbine turning it by about a rope belt pulley system. As new uses and users for electricity increased, by the early 1900s the demand for electricity in Sacramento and its adjacent cities had out-paced the capacity of the expanded Folsom Powerhouse. Larger hydroelectric plants and dams were built along the Yuba, Feather, and Tuolumne Rivers in order to provide power for Northern California. The San Francisco-based California Gas and Electric Company bought the Folsom Powerhouse by 1902. When the company was reorganized into the Pacific Gas and Electric Company in 1906, it retooled the powerhouse and forebay.
See also
Old Folsom Powerhouse Station A
National Register of Historic Places
List of Historic Civil Engineering Landmarks
List of Historic Mechanical Engineering Landmarks
List of California state parks
Revolving armature alternator
References
External links
Folsom Powerhouse SHP
Friends of the Folsom Powerhouse
California State Historic Parks
Buildings and structures in Sacramento County, California
Buildings and structures in Folsom, California
Hydroelectric power plants in California
American River (California)
Folsom, California
Museums in Sacramento County, California
Parks in Sacramento County, California
Technology museums in California
Electric power transmission systems in the United States
Energy infrastructure completed in 1895
1895 establishments in California
California Historical Landmarks
Historic American Engineering Record in California
Historic Civil Engineering Landmarks
Industrial buildings and structures on the National Register of Historic Places in California
National Historic Landmarks in California
National Register of Historic Places in Sacramento County, California
Protected areas established in 1956
1956 establishments in California
Energy infrastructure on the National Register of Historic Places | Folsom Powerhouse State Historic Park | [
"Engineering"
] | 2,669 | [
"Civil engineering",
"Historic Civil Engineering Landmarks"
] |
4,242,881 | https://en.wikipedia.org/wiki/Early-warning%20radar | An early-warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as early as possible before the intruder reaches its target, giving the air defences the maximum time in which to operate. This contrasts with systems used primarily for tracking or gun laying, which tend to offer shorter ranges but offer much higher accuracy.
EW radars tend to share a number of design features that improve their performance in the role. For instance, EW radar typically operates at lower frequencies, and thus longer wavelengths, than other types. This greatly reduces their interaction with rain and snow in the air, and therefore improves their performance in the long-range role where their coverage area will often include precipitation. This also has the side-effect of lowering their optical resolution, but this is not important in this role. Likewise, EW radars often use much lower pulse repetition frequency to maximize their range, at the cost of signal strength, and offset this with long pulse widths, which increases the signal at the cost of lowering range resolution.
The canonical EW radar is the British Chain Home system, which entered full-time service in 1938. It used a very low pulse repetition of 25 pps and very powerful transmissions (for the era) reaching 1Β MW in late-war upgrades. The German Freya and US CXAM (Navy) and SCR-270 (Army) were similar. Post-war models moved to the microwave range in ever-increasingly powerful models that reached the 50Β MW range by the 1960s. Since then, improvements in receiver electronics has greatly reduced the amount of signal needed to produce an accurate image, and in modern examples the transmitted power is much less; the AN/FPS-117 offers range from 25Β kW. EW radars are also highly susceptible to radar jamming and often include advanced frequency hopping systems to reduce this problem.
History
The first early-warning radars were the British Chain Home, the German Freya, the US CXAM (Navy) and SCR-270 (Army), and the Soviet Union . By modern standards these were quite short range, typically about . This "short" distance is a side effect of radio propagation at the long wavelengths being used at the time, which were generally limited to line-of-sight. Although techniques for long-range propagation were known and widely used for shortwave radio, the ability to process the complex return signal was simply not possible at the time.
Cold War
To counter the threat of Soviet bombers flying over the Arctic, the U.S. and Canada developed the DEW Line. Other examples (Pinetree Line) have since been built with even better performance. An alternative early warning design was the Mid-Canada Line, which provided "line breaking" indication across the middle of Canada, with no provision to identify the target's exact location or direction of travel. Starting in the 1950s, a number of over-the-horizon radars were developed that greatly extended detection ranges, generally by bouncing the signal off the ionosphere.
Modern day
Today the early warning role has been supplanted to a large degree by airborne early warning platforms. By placing the radar on an aircraft, the line-of-sight to the horizon is greatly extended. This allows the radar to use high-frequency signals, offering high resolution, while still offering long range. A major exception to this rule are radars intended to warn of ballistic missile attacks, like BMEWS, as the high-altitude exo-atmospheric trajectory of these weapons allows them to be seen at great ranges even from ground-based radars.
Early systems
Chain Home
Chain Home Low
SCR-270
AN/CPS-1
CXAM radar
Freya radar
1950s through 70s
Pinetree Line
Mid-Canada Line
Distant Early Warning Line
Duga radar
BMEWS
AMES Type 80
AMES Type 84
AMES Type 85
ROTOR
Dnestr radar
Dnepr radar
Daryal radar
Linesman/Mediator
Operational systems
AWACS, the US airborne system of surveillance radar plus command and control functions
Daryal radar, Soviet and Russian early warning radar
Dnestr radar, Soviet and Russian early warning radars
Don-2N radar, Russian missile defence radar in Moscow
Duga radar, Soviet over-the-horizon early-warning radar system
Dunay radar, Soviet missile defence radar
GIRAFFE, Swedish family of early warning radar systems
EL/M-2080 Green Pine, Israeli ground-based missile-defense radar by Elta
EL/M-2090, Israeli ground-based very long range early-warning radar system
Erieye, Swedish airborne system of surveillance radar
Jindalee, Australian over-the-horizon radar network
Long Range Discrimination Radar, the US radar system
North Warning System, a joint United States and Canadian early-warning radar system
NETRA, Indian airborne early warning and control aircraft
PAVE PAWS, the US early warning radar
RAF Fylingdales, British early warning radar
Red Color, Israeli early warning radar system
Sea-based X-band Radar, the US sea-based early-warning radar station
Voronezh radar, Russian early warning radar system
ESR-32A, Egyptian air surveillance and early-warning radar system
ASELSAN ALP-300G
References
Radar
Early warning systems | Early-warning radar | [
"Technology"
] | 1,074 | [
"Warning systems",
"Early warning systems"
] |
4,242,960 | https://en.wikipedia.org/wiki/National%20Fluid%20Power%20Association | The National Fluid Power Association (NFPA) is an American 501(c)6 industry trade association, founded in 1953.
The NFPA's mission is to serve as a forum where all fluid power channel partners work together to advance fluid power technology, strengthen the fluid power industry, and foster members' success. NFPA members include more than 315 manufacturers of fluid power systems and components, fluid power distributors, suppliers to the fluid power industry, educators and researchers.
References
External links
National Fluid Power Association
Fluid Power Distributors Association
Fluid Power Education Foundation
Fluid Power Society
Hydraulic engineering organizations
Trade associations based in the United States | National Fluid Power Association | [
"Engineering"
] | 126 | [
"Hydraulic engineering organizations",
"Civil engineering organizations"
] |
8,876,082 | https://en.wikipedia.org/wiki/Kirkman%27s%20schoolgirl%20problem | Kirkman's schoolgirl problem is a problem in combinatorics proposed by Thomas Penyngton Kirkman in 1850 as Query VI in The Lady's and Gentleman's Diary (pg.48). The problem states:
Fifteen young ladies in a school walk out three abreast for seven days in succession: it is required to arrange them daily so that no two shall walk twice abreast.
Solutions
A solution to this problem is an example of a Kirkman triple system, which is a Steiner triple system having a parallelism, that is, a partition of the blocks of the triple system into parallel classes which are themselves partitions of the points into disjoint blocks. Such Steiner systems that have a parallelism are also called resolvable.
There are exactly seven non-isomorphic solutions to the schoolgirl problem, as originally listed by Frank Nelson Cole in Kirkman Parades in 1922. The seven solutions are summarized in the table below, denoting the 15 girls with the letters A to O.
From the number of automorphisms for each solution and the definition of an automorphism group, the total number of solutions including isomorphic solutions is therefore:
.
History
The problem has a long and storied history. This section is based on historical work done at different times by Robin Wilson and by Louise Duffield Cummings. The history is as follows:
In 1844, Wesley Woolhouse, the editor of The Lady's and Gentleman's Diary at the time, asked the general question: "Determine the number of combinations that can be made out of n symbols, p symbols in each; with this limitation, that no combination of q symbols, which may appear in any one of them shall be repeated in any other." Only two answers were received, one incorrect and the other correctly answering the question with . As the question did not ask for anything more than the number of combinations, nothing was received about the conditions on n, p, or q when such a solution could be achieved.
In 1846, Woolhouse asked: "How many triads can be made out of n symbols, so that no pair of symbols shall be comprised more than once among them?". This is equivalent to repeating his 1844 question with the values p = 3 and q = 2.
In 1847, at age 41, Thomas Kirkman published his paper titled On a Problem in Combinations which comprehensively described and solved the problem of constructing triple systems of order n where n = 1 or 3 (mod 6). He also considered other values of n even though perfect balance would not be possible. He gave two different sequences of triple systems, one for n = 7, 15, 19, 27, etc., and another for n = 9, 13, 25, etc. Using these propositions, he proved that triple systems exist for all values of n = 1 or 3 (mod 6) (not necessarily resolvable ones, but triple systems in general). He also described resolvable triple systems in detail in that paper, particularly for n = 9 and 15; resolvable triple systems are now known as Kirkman triple systems. He could not conclusively say for what other values of n would resolvable triple systems exist; that problem would not be solved until the 1960s (see below).
In 1850, Kirkman posed the 15 schoolgirl problem, which would become much more famous than the 1847 paper he had already written. Several solutions were received. Kirkman himself gave a solution that later would be found to be isomorphic to Solution I above. Kirkman claimed it to be the only possible solution but that was incorrect. Arthur Cayley's solution would be later found to be isomorphic to Solution II. Both solutions could be embedded in PG(3,2) though that geometry was not known at the time. However, in publishing his solutions to the schoolgirl problem, Kirkman neglected to refer readers to his own 1847 paper, and this omission would have serious consequences for invention and priority as seen below.
Also in 1850, James Joseph Sylvester asked if there could be 13 different solutions to the 15-schoolgirl problem that would use all triples exactly once overall, observing that . In words, is it possible for the girls to march every day for 13 weeks, such that every two girls march together exactly once each week and every three girls march together exactly once in the term of 13 weeks? This problem was much harder, and a computational solution would finally be provided in 1974 by RHF Denniston (see below).
In 1852, Robert Richard Anstice provided a cyclic solution, made by constructing the first day's five triples to be 0Gg, AbC, aDE, cef, BdF on the 15 symbols 0ABCDEFGabcdefg and then cyclically shifting each subsequent day by one letter while leaving 0 unchanged (uppercase staying uppercase and lowercase staying lowercase). If the four triples without the 0 element (AbC, aDE, cef, BdF) are taken and uppercase converted to lowercase (abc, ade, cef, bdf) they form what would later be called the Pasch configuration. The Pasch configuration would become important in isomorph rejection techniques in the 20th century.
In 1853, Jakob Steiner, completely unaware of Kirkman's 1847 paper, published his paper titled Combinatorische Aufgabe which reintroduced the concept of triple systems but did not mention resolvability into separate parallel classes. Steiner noted that it is necessary for n to be 1 or 3 (mod 6) but left an open question as to when this would be realized, unaware that Kirkman had already settled that question in 1847. As this paper was more widely read by the European mathematical establishment, triple systems later became known as Steiner triple systems.
In 1859, Michel Reiss answered the questions raised by Steiner, using both methodology and notation so similar to Kirkman's 1847 work (without acknowledging Kirkman), that subsequent authors such as Louise Cummings have called him out for plagiarism. Kirkman himself expressed his bitterness.
In 1860, Benjamin Peirce unified several disparate solutions presented thus far, and showed that there were three possible cyclic solution structures, one corresponding to Anstice's work, one based on Kirkman's solution, and one on Cayley's.
In 1861, James Joseph Sylvester revisited the problem and tried to claim that he had invented it, and that his Cambridge lectures had been the source of Kirkman's work. Kirkman quickly rebuffed his claims, stating that when he wrote his papers he had never been to Cambridge or heard of Sylvester's work. This priority dispute led to a falling out between Sylvester and Kirkman.
In 1861-1862, Kirkman had a falling out with Arthur Cayley over an unrelated matter (Cayley's choosing not to publish a series of papers by Kirkman on group theory and polyhedra which cost Kirkman recognition by the mathematical community in Europe), further contributing to his being sidelined by the mathematics establishment. His comprehensive 1847 paper in particular was forgotten, with many subsequent authors either crediting Steiner or Reiss, unaware of the history.
The schoolgirl puzzle's popularity itself was unaffected by Kirkman's academic conflicts, and in the late 19th and early 20th centuries the puzzle appeared in several recreational mathematics books by Γdouard Lucas, Rouse Ball, Wilhelm Ahrens, and Henry Dudeney. In his lifetime, Kirkman would complain about his serious mathematical work being eclipsed by the popularity of the schoolgirl problem. Kirkman died in 1895.
In 1918, Kirkman's serious mathematical work was brought back to wider attention by Louise Duffield Cummings in a paper titled An Undervalued Kirkman Paper which discussed the early history of the field and corrected the historical omission.
At about the same time, Cummings was working with Frank Nelson Cole and Henry Seely White on triple systems. This culminated in their famous and widely cited 1919 paper Complete classification of triad systems on 15 elements which was the first paper to lay out all 80 solutions to the Steiner triple system of size 15. These included both resolvable and non-resolvable systems.
In 1922, Cole published his paper Kirkman Parades which listed for the first time all seven non-isomorphic solutions to the 15 schoolgirl problem, thus answering a long-standing question since the 1850s. The seven Kirkman solutions correspond to four different Steiner systems when resolvability into parallel classes is removed as a constraint. Three of the Steiner systems have two possible ways of being separated into parallel classes, meaning two Kirkman solutions each, while the fourth has only one, giving seven Kirkman solutions overall.
In the 1960s, it was proved that Kirkman triple systems exist for all orders n = 3 (mod 6). This was first proved by Lu Jiaxi () in 1965, and he submitted it to Acta Mathematica Sinica but the journal erroneously thought the problem had been solved already and rejected his paper in 1966, which was later found to be a serious mistake. His subsequent academic contributions were disrupted by the Cultural Revolution and rejected again. In 1968, the generalized theorem was proven independently by D. K. Ray-Chaudhuri and R. M. Wilson.
In 1974, RHF Denniston solved the Sylvester problem of constructing 13 disjoint Kirkman solutions and using them to cover all 455 triples on the 15 girls. His solution is discussed below.
Sylvester's problem
James Joseph Sylvester in 1850 asked if 13 disjoint Kirkman systems of 35 triples each could be constructed to use all triples on 15 girls. No solution was found until 1974 when RHF Denniston at the University of Leicester constructed it with a computer. Denniston's insight was to create a single-week Kirkman solution in such a way that it could be permuted according to a specific permutation of cycle length 13 to create disjoint solutions for subsequent weeks; he chose a permutation with a single 13-cycle and two fixed points like (1 2 3 4 5 6 7 8 9 10 11 12 13)(14)(15). Under this permutation, a triple like 123 would map to 234, 345, ... (11, 12, 13), (12, 13, 1) and (13, 1, 2) before repeating. Denniston thus classified the 455 triples into 35 rows of 13 triples each, each row being the orbit of a given triple under the permutation. In order to construct a Sylvester solution, no single-week Kirkman solution could use two triples from the same row, otherwise they would eventually collide when the permutation was applied to one of them. Solving Sylvester's problem is equivalent to finding one triple from each of the 35 rows such that the 35 triples together make a Kirkman solution. He then asked an Elliott 4130 computer to do exactly that search, which took him 7 hours to find this first-week solution, labeling the 15 girls with the letters A to O:
Day 1 ABJ CEM FKL HIN DGO
Day 2 ACH DEI FGM JLN BKO
Day 3 ADL BHM GIK CFN EJO
Day 4 AEG BIL CJK DMN FHO
Day 5 AFI BCD GHJ EKN LMO
Day 6 AKM DFJ EHL BGN CIO
Day 7 BEF CGL DHK IJM ANO
He stopped the search at that point, not looking to establish uniqueness.
The American minimalist composer Tom Johnson composed a piece of music called Kirkman's Ladies based on Denniston's solution.
As of 2021, it is not known whether there are other non-isomorphic solutions to Sylvester's problem, or how many solutions there are.
9 schoolgirls and extensions
The equivalent of the Kirkman problem for 9 schoolgirls results in S(2,3,9), an affine plane isomorphic to the following triples on each day:
Day 1: 123 456 789
Day 2: 147 258 369
Day 3: 159 267 348
Day 4: 168 249 357
The corresponding Sylvester problem asks for 7 different S(2,3,9) systems of 12 triples each, together covering all triples. This solution was known to Bays (1917) which was found again from a different direction by Earl Kramer and Dale Mesner in a 1974 paper titled Intersections Among Steiner Systems (J Combinatorial Theory, Vol 16 pp 273-285). There can indeed be 7 disjoint S(2,3,9) systems, and all such sets of 7 fall into two non-isomorphic categories of sizes 8640 and 6720, with 42 and 54 automorphisms respectively.
Solution 1:
Day 1 Day 2 Day 3 Day 4
Week 1 ABC.DEF.GHI ADG.BEH.CFI AEI.BFG.CDH AFH.BDI.CEG
Week 2 ABD.CEH.FGI ACF.BGH.DEI AEG.BCI.DFH AHI.BEF.CDG
Week 3 ABE.CDI.FGH ACG.BDF.EHI ADH.BGI.CEF AFI.BCH.DEG
Week 4 ABF.CEI.DGH ACD.BHI.EFG AEH.BCG.DFI AGI.BDE.CFH
Week 5 ABG.CDE.FHI ACH.BEI.DFG ADI.BCF.EGH AEF.BDH.CGI
Week 6 ABH.CDF.EGI ACI.BDG.EFH ADE.BFI.CGH AFG.BCE.DHI
Week 7 ABI.CFG.DEH ACE.BFH.DGI ADF.BEG.CHI AGH.BCD.EFI
Solution 1 has 42 automorphisms, generated by the permutations (AΒ IΒ DΒ CΒ FΒ H)(BΒ G) and (CΒ FΒ DΒ HΒ EΒ I)(BΒ G). Applying the 9! = 362880 permutations of ABCDEFGHI, there are 362880/42 = 8640 different solutions all isomorphic to Solution 1.
Solution 2:
Day 1 Day 2 Day 3 Day 4
Week 1 ABC.DEF.GHI ADG.BEH.CFI AEI.BFG.CDH AFH.BDI.CEG
Week 2 ABD.CEH.FGI ACF.BGH.DEI AEG.BCI.DFH AHI.BEF.CDG
Week 3 ABE.CGH.DFI ACI.BFH.DEG ADH.BGI.CEF AFG.BCD.EHI
Week 4 ABF.CGI.DEH ACE.BDG.FHI ADI.BCH.EFG AGH.BEI.CDF
Week 5 ABG.CDI.EFH ACH.BDF.EGI ADE.BHI.CFG AFI.BCE.DGH
Week 6 ABH.CEI.DFG ACD.BFI.EGH AEF.BCG.DHI AGI.BDE.CFH
Week 7 ABI.CDE.FGH ACG.BDH.EFI ADF.BEG.CHI AEH.BCF.DGI
Solution 2 has 54 automorphisms, generated by the permutations (AΒ BΒ D)(CΒ HΒ E)(FΒ GΒ I) and (AΒ IΒ FΒ DΒ EΒ H)(BΒ G). Applying the 9! = 362880 permutations of ABCDEFGHI, there are 362880/54 = 6720 different solutions all isomorphic to Solution 2.
Thus there are 8640 + 6720 = 15360 solutions in total, falling into two non-isomorphic categories.
In addition to S(2,3,9), Kramer and Mesner examined other systems that could be derived from S(5,6,12) and found that there could be up to 2 disjoint S(5,6,12) systems, up to 2 disjoint S(4,5,11) systems, and up to 5 disjoint S(3,4,10) systems. All such sets of 2 or 5 are respectively isomorphic to each other.
Larger systems and continuing research
In the 21st century, analogues of Sylvester's problem have been visited by other authors under terms like "Disjoint Steiner systems" or "Disjoint Kirkman systems" or "LKTS" (Large Sets of Kirkman Triple Systems), for n > 15. Similar sets of disjoint Steiner systems have also been investigated for the S(5,8,24) Steiner system in addition to triple systems.
Galois geometry
In 1910 the problem was addressed using Galois geometry by George Conwell.
The Galois field GF(2) with two elements is used with four homogeneous coordinates to form PG(3,2) which has 15 points, 3 points to a line, 7 points and 7 lines in a plane. A plane can be considered a complete quadrilateral together with the line through its diagonal points. Each point is on 7 lines, and there are 35 lines in all.
The lines of PG(3,2) are identified by their PlΓΌcker coordinates in PG(5,2) with 63 points, 35 of which represent lines of PG(3,2). These 35 points form the surface S known as the Klein quadric. For each of the 28 points off S there are 6 lines through it which do not intersect S.
As there are seven days in a week, the heptad is an important part of the solution:
A heptad is determined by any two of its points. Each of the 28 points off S lies in two heptads. There are 8 heptads. The projective linear group PGL(3,2) is isomorphic the alternating group on the 8 heptads.
The schoolgirl problem consists in finding seven lines in the 5-space which do not intersect and such that any two lines always have a heptad in common.
Spreads and packing
In PG(3,2), a partition of the points into lines is called a spread, and a partition of the lines into spreads is called a or . There are 56 spreads and 240 packings. When Hirschfeld considered the problem in his Finite Projective Spaces of Three Dimensions (1985), he noted that some solutions correspond to packings of PG(3,2), essentially as described by Conwell above, and he presented two of them.
Generalization
The problem can be generalized to girls, where must be an odd multiple of 3 (that is ), walking in triplets for days, with the requirement, again, that no pair of girls walk in the same row twice. The solution to this generalisation is a Steiner triple system, an S(2, 3, 6t + 3) with parallelism (that is, one in which each of the 6t + 3 elements occurs exactly once in each block of 3-element sets), known as a Kirkman triple system. It is this generalization of the problem that Kirkman discussed first, while the famous special case was only proposed later. A complete solution to the general case was published by D. K. Ray-Chaudhuri and R. M. Wilson in 1968, though it had already been solved by Lu Jiaxi () in 1965, but had not been published at that time.
Many variations of the basic problem can be considered. Alan Hartman solves a problem of this type with the requirement that no trio walks in a row of four more than once using Steiner quadruple systems.
More recently a similar problem known as the Social Golfer Problem has gained interest that deals with 32 golfers who want to get to play with different people each day in groups of 4, over the course of 10 days.
As this is a regrouping strategy where all groups are orthogonal, this process within the problem of organising a large group into smaller groups where no two people share the same group twice can be referred to as orthogonal regrouping.
The Resolvable Coverings problem considers the general girls, groups case where each pair of girls must be in the same group at some point, but we want to use as few days as possible. This can, for example, be used to schedule a rotating table plan, in which each pair of guests must at some point be at the same table.
The Oberwolfach problem, of decomposing a complete graph into edge-disjoint copies of a given graph, also generalizes Kirkman's schoolgirl problem. Kirkman's problem is the special case of the Oberwolfach problem in which the graph consists of five disjoint triangles.
See also
Cooperative learning strategy for increasing interaction within classroom teaching
Dobble card game
Progressive dinner party designs
Speed Networking events
Sports Competitions
Combinatorics
R M Wilson
Dijen K. Ray-Chaudhuri
Discrete mathematics
Notes
References
External links
String (March, 2015) - Solution visualised, Stack Exchange
Combinatorial design
Mathematical problems
Families of sets | Kirkman's schoolgirl problem | [
"Mathematics"
] | 4,411 | [
"Combinatorial design",
"Combinatorics",
"Families of sets",
"Basic concepts in set theory",
"Mathematical problems"
] |
8,876,908 | https://en.wikipedia.org/wiki/Natural%20Selection%202 | Natural Selection 2 is a multiplayer video game which combines first-person shooter and real-time strategy rules. It is set in a science fiction universe in which a human team fights an alien team for control of resources and territory in large and elaborate indoor facilities. It is the sequel to Natural Selection.
Gameplay
Like its predecessor, Natural Selection 2 features two opposing teams of players, Kharaa (Aliens) and Frontiersmen (Marines), seeking to destroy the other's respective base. While the two teams have the same essential goals, gameplay for each team varies drastically. Marines largely rely on guns and other pieces of technology to annihilate the alien presence. Aliens, however, rely primarily on melee attacks. Certain alien lifeforms can walk on walls, fly, and even dash forward in the blink of an eye. Players also have a currency system which they use to buy better equipment or evolve into higher lifeforms.
The primary feature that differentiates Natural Selection 2 from others in the FPS genre is its strategy component. Both teams may have one player act as a commander, who is given a top-down view of the map and plays the game in a Real-time strategy perspective. The commander can place buildings, research upgrades and has a number of abilities to support their team (dropping health and ammo packs, using certain support units to aid in combat or building, or erecting walls to block enemy movement), at the cost of resources. Buildings in Natural Selection are designed to aid players in their offensive, defensive, stealth and speed capabilities.
For a team to achieve victory, they must eliminate all of the opposing team command structures (Hive of the Kharaa, Command Station of the Frontiersmen). The Aliens also have the option of eliminating all infantry portals (Marine spawn structure) and any alive Marines; however because eggs (Alien spawn structure) automatically spawn around hives, Marines cannot do the same.
Development
A game engine originally dubbed "Evolution" was developed specifically for the game. It has since been renamed "Spark". The game engine utilizes the Lua scripting language for game logic, allowing for easy expansion of the game's mechanics. Physics support is provided by several third-party libraries.
The game was officially announced in October 2006. It was to be developed by the Natural Selection creator's newly founded company, Unknown Worlds. Charlie βFlayraβ Cleveland will continue his work on the game and Cory Strader (concept artist from Natural Selection) will also be contributing concept artwork.
On December 1, 2006 the first major announcement of a possible feature was announced, named 'Dynamic Infestation'. A video containing an example of Dynamic Infestation was posted on the Unknown Worlds development blog.
On August 31, 2007, podcasts by Max McGuire and Charlie Cleveland were released. These audio updates have since been released at irregular intervals. They discuss the development process, funding and focus, and serve as a basis for interviews with other names in the industry.
On April 6, 2008, Unknown Worlds established an office.
On July 10, 2008, Unknown Worlds announced their move from the Source Engine to an in-house developed engine dubbed "Spark". Concept artwork was often shown on the Unknown Worlds development blog.
In October 2009, Unknown Worlds confirmed plans to support Mac OS X, Linux platforms and perhaps console. However, in February 2010, Max McGuire announced that OS X, Linux, and Xbox support would not be available at the game's initial launch. It was also revealed that Natural Selection amassed over $200,000 in pre-orders and $500,000 through angel investors.
On April 9, 2010 a standalone Engine Build became available which included an external map creation utility. On May 7, the Engine Build started using Steam as its primary distribution and update source.
On 13 July 2010, Unknown Worlds Entertainment announced that a private alpha was to be released through Steam for all Special Edition pre-order customers on 26 July 2010. It will be updated throughout the game development and eventually become the beta release. The full release version of the game will subsequently follow.
The alpha test started on July 26, 2010, with those who pre-ordered the game's "Special Edition" able to activate it via Steam. The game was released on Steam on October 31, 2012.
On November 18, 2010, Unknown Worlds Entertainment updated the status from private alpha to closed beta, allowing anyone who had previously pre-ordered either edition of the game, plus the first 10,000 pre-orders after the announcement was made, into the beta. This was primarily to bring in more capital.
On February 14, 2023, Unknown Worlds Entertainment announced that the active development of Natural Selection 2 has ended.
Post-release
A few years after Natural Selection 2 was released, Unknown Worlds turned over development to a small team made up of community members. In November 2015, UWE took over development once more, with eight members of the community development team being hired, most working part-time. The initial announcement led to controversy in the community, with one community developer stating they would no longer be working on the game, believing he and others were poorly treated in the community.
Reception
The game sold 144,000 copies in its first week, earning over $1 million. As of February 26, 2013 the game has sold 300,000 copies.
The review aggregator Metacritic shows generally favorable reviews, with a Metascore of 80.
References
External links
2012 video games
First-person strategy video games
Indie games
Lua (programming language)-scripted video games
Multiplayer online games
Multiplayer video games
Science fiction video games
Video game sequels
Video games developed in the United States
Windows games
Linux games
Video games with Steam Workshop support
Asymmetrical multiplayer video games
Unknown Worlds Entertainment games
Cancelled Linux games | Natural Selection 2 | [
"Physics"
] | 1,166 | [
"Asymmetrical multiplayer video games",
"Symmetry",
"Asymmetry"
] |
8,877,468 | https://en.wikipedia.org/wiki/Molecular%20Query%20Language | The Molecular Query Language (MQL) was designed to allow more complex, problem-specific search methods in chemoinformatics. In contrast to the widely used SMARTS queries, MQL provides for the specification of spatial and physicochemical properties of atoms and bonds. Additionally, it can easily be extended to handle non-atom-based graphs, also known as "reduced feature" graphs.
The query language is based on an extended BackusβNaur form (EBNF) using JavaCC.
Notes and references
E. Proschak, J. K. Wegner, A. SchΓΌller, G. Schneider, U. Fechner, Molecular Query Language (MQL)-A Context-Free Grammar for Substructure Matching, J. Chem. Inf. Model., 2007, 47, 295-301.
See also
SMARTS
International Chemical Identifier
External links
Java Webstart application for MQL
Cheminformatics | Molecular Query Language | [
"Chemistry"
] | 205 | [
"Computational chemistry",
"nan",
"Cheminformatics"
] |
8,877,643 | https://en.wikipedia.org/wiki/Misner%20space | Misner space is an abstract mathematical spacetime, first described by Charles W. Misner. It is also known as the Lorentzian orbifold . It is a simplified, two-dimensional version of the TaubβNUT spacetime. It contains a non-curvature singularity and is an important counterexample to various hypotheses in general relativity.
Michio Kaku develops the following analogy for understanding the concept: "Misner space is an idealized space in which a room, for example, becomes the entire universe. For example, every point on the left wall of the room is identical to the corresponding point on the right wall, such that if you were to walk toward the left wall you will walk through the wall and appear from the right wall. This suggests that the left and right wall are joined, in some sense, as in a cylinder. The opposite walls are thus all identified with each other, and the ceiling is likewise identified with the floor. Misner space is often studied because it has the same topology as a wormhole but is much simpler to handle mathematically. If the walls move, then time travel might be possible within the Misner universe."
Metric
The simplest description of Misner space is to consider two-dimensional Minkowski space with the metric
with the identification of every pair of spacetime points by a constant boost
It can also be defined directly on the cylinder manifold with coordinates by the metric
The two coordinates are related by the map
and
Causality
Misner space is a standard example for the study of causality since it contains both closed timelike curves and a compactly generated Cauchy horizon, while still being flat (since it is just Minkowski space). With the coordinates , the loop defined by , with tangent vector , has the norm , making it a closed null curve. This is the chronology horizon : there are no closed timelike curves in the region , while every point admits a closed timelike curve through it in the region .
This is due to the tipping of the light cones which, for , remains above lines of constant but will open beyond that line for , causing any loop of constant to be a closed timelike curve.
Chronology protection
Misner space was the first spacetime where the notion of chronology protection was used for quantum fields, by showing that in the semiclassical approximation, the expectation value of the stress-energy tensor for the vacuum is divergent.
References
Further reading
General relativity | Misner space | [
"Physics"
] | 499 | [
"General relativity",
"Theory of relativity"
] |
8,877,946 | https://en.wikipedia.org/wiki/CXCL14 | Chemokine (C-X-C motif) ligand 14 (CXCL14) is a small cytokine belonging to the CXC chemokine family that is also known as BRAK (for breast and kidney-expressed chemokine). Mature CXCL14 has many of the conserved features of the CXC chemokine subfamily but has some differences too, such as a shorter N-terminus and five extra amino acids in the region between its third and fourth cysteines. CXCL14 is constitutively expressed at high levels in many normal tissues, where its cellular source is thought to be fibroblasts.
However, it is reduced or absent from most cancer cells. This chemokine is chemotactic for monocytes and can activate these cells in the presence of an inflammatory mediator called prostaglandin-E2 (PGE2). It is also a potent chemoattractant and activator of dendritic cells, is implicated in homing of these cells, and can stimulate the migration of activated NK cells. CXCL14 also inhibits angiogenesis, possibly as a result of its ability to block endothelial cell chemotaxis. The gene for CXCL14 contains four exons and is located on chromosome 5 in humans.
References
Cytokines | CXCL14 | [
"Chemistry"
] | 286 | [
"Cytokines",
"Signal transduction"
] |
8,878,119 | https://en.wikipedia.org/wiki/Transit%20map | A transit map is a topological map in the form of a schematic diagram used to illustrate the routes and stations within a public transport systemβwhether this be bus, tram, rapid transit, commuter rail or ferry routes. Metro maps, subway maps, or tube maps of metropolitan railways are some common examples.
The primary function of a transit map is to facilitating the passengers' orientation and navigation, helping them to efficiently use the public transport system and identify which stations function as interchange between lines.
Unlike conventional maps, transit maps are usually not designed to be geographically accurate. Instead, to increase legibility, simplicity and visual aesthetic quality, designers simplify complex routes by using abstract geometry - straight lines, fixed angles and often a fixed distance between stations, compressing those in the outer area of the system and expanding those close to the center. This transformation of a topographical map into a schematic diagram is known as schematization. Although they prioritize clarity over strict geographic accuracy, the relative positions and connections between stations and routes are still accurately depicted for effective navigation. Transit map design places a strong emphasis on user needs, ensuring that layouts and visual elements are optimized to empower passengers with intuitive navigation tools, facilitating seamless decision-making and enhancing overall travel experience.
The main components of a transit map include symbols or named icons representing stations, stops, and interchanges, color-coded lines indicating available routes and transportation services, capturing not only the essential structure of transport networks, but also the city's iconic landscape itself. Its layout, such as geographic, multilinear, radial, concentric circular, grid, or hybrid, is chosen based on geographical intricacies, network complexity, and user preference. Careful consideration is given to icon choice to distinguish different kinds of stations (regular, interchange or terminal), line styles, colors, typography, and their consistent application for clear, effective and intuitive communication.
Transit maps can be found in the transit vehicles, at the platforms or in printed timetables. They are also accessible through digital platforms like mobile apps and websites, ensuring widespread availability and convenience for passengers.
History
The mapping of transit systems was at first generally geographically accurate, but abstract route-maps of individual lines (usually displayed inside the carriages) can be traced back as early as 1908 (London's District line), and certainly there are examples from European and American railroad cartography as early as the 1890s where geographical features have been removed and the routes of lines have been artificially straightened out. But it was George Dow of the London and North Eastern Railway who was the first to launch a diagrammatic representation of an entire rail transport network (in 1929); his work is seen by historians of the subject as being part of the inspiration for Harry Beck when he launched his iconic London Underground map in 1933.
After this pioneering work, many transit authorities worldwide imitated the diagrammatic look for their own networks, some while continuing to also publish hybrid versions that were geographically accurate.
Early maps of the Berlin U-Bahn, Berlin S-Bahn, Boston T, Paris MΓ©tro, and New York City Subway also exhibited some elements of the diagrammatic form.
The new Madrid Metro map (of 2007), designed by the RaRo Agency, took the idea of a simple diagram one step further by becoming one of the first produced for a major network to remove diagonal lines altogether; it is constituted just by horizontal and vertical lines only at right angles to each other. After many complaints over its disadvantages, the company reverted to the previous map in 2013.
Transit maps are now increasingly digitized and can be shown in many forms online.
Elements
The primary purpose of a transit map is to help passengersβespecially those unfamiliar with the systemβto take the correct routes to travel between two points; this may include having to change vehicle or mode in the course of the trip. The map uses symbols to illustrate the lines, stations and transfer points, as well as a system of geographic identification. At the same time the map must remain simple to allow overview, and be usable by those unfamiliar with the geography of the area.
Stations are marked with symbols that break the line, along with their names, so they may be referred to on other maps or travel itineraries. Further help may be granted through the inclusion of important tourist attractions and other locations such as the city center; these may be identified through symbols or wording.
Color coding allows the map to specify each route in an easy way, allowing the users to quickly identify where each specific route goes; if it does not go to the desired destination, the colors and symbols allow the user to identify a feasible point of transfer between lines. Symbols such as aircraft may be used to illustrate airports, and symbols of trains may be used to identify stations that allow transfer to other modes, such as commuter or intercity train services. With the widespread use of zone pricing for fare calculation, systems that span more than one zone need a system to inform the use which zone a particular station is located in. Common ways include varying the tone of the background color, or by running a weak line along the zone boundaries.
Many transit authorities publish multiple maps of their systems; this can be done by isolating one mode of transport, for instance only rapid transit or only bus, onto a single map, or instead the authorities publish maps covering only a limited area, but with greater detail. Another modification is to produce geographically accurate maps of the system, to allow users to better understand the routes. Even if official geographical accurate maps are not available, these can often be obtained from unofficial sources since the information is available from other sources.
Iconic status
There are a growing number of books, websites and works of art on the subject of urban rail and metro map design and use. There are now hundreds of examples of diagrams in an urban rail or metro map style that are used to represent everything from other transit networks like buses and national rail services to sewerage systems and Derbyshire public houses.
One of the most well-known adaptations of an urban rail map was The Great Bear, a lithograph by Simon Patterson. First shown in 1992 and nominated for the Turner Prize, The Great Bear replaces station names on the London Underground map with those of explorers, saints, film stars, philosophers and comedians. Other artists such as Scott Rosenbaum, and Ralph Gray have also taken the iconic style of the urban rail map and made new artistic creations ranging from the abstract to the Solar System. Following the success of these the idea of adapting other urban rail and metro maps has spread so that now almost every major subway or rapid transit system with a map has been doctored with different names, often anagrams of the original station name.
Some maps including those for the rapid transit systems of New York City, Washington D.C., Boston, Montreal, and Denver, have been recreated to include the names of local bars that have a good selection of craft beers.
See also
Bicycle map
Isochrone map
Metrominuto
Road map
Notes
References
Further reading
Mr Beck's Underground Map, Ken Garland, Capital Transport, London, 1994.
No Need To Ask, David Leboff and Tim Demuth, Capital Transport, London, 1999.
Metro Maps of the World, Mark Ovenden, Capital Transport, London, 2003.
Das Berliner U- und S-Bahnnetz, Alfred B. Gottwaldt, TransPress, Stuttgart, 2004.
Telling the passenger where to get off, Andrew Dow, Capital Transport, London, 2005.
Underground Maps After Beck, Maxwell J. Roberts, Capital Transport, London, 2005.
Transit Maps of the world, Mark Ovenden, Penguin books, New York, 2007.
External links
Subways Transport, an extensive site with archive maps on virtually every urban rail system in the world.
Urban Rail
Infographics
Pictograms
Public transport | Transit map | [
"Mathematics"
] | 1,587 | [
"Symbols",
"Pictograms"
] |
8,879,085 | https://en.wikipedia.org/wiki/Mobile%20broadband | Mobile broadband is the marketing term for wireless Internet access via mobile (cell) networks. Access to the network can be made through a portable modem, wireless modem, or a tablet/smartphone (possibly tethered) or other mobile device. The first wireless Internet access became available in 1991 as part of the second generation (2G) of mobile phone technology. Higher speeds became available in 2001 and 2006 as part of the third (3G) and fourth (4G) generations. In 2011, 90% of the world's population lived in areas with 2G coverage, while 45% lived in areas with 2G and 3G coverage. Mobile broadband uses the spectrum of 225 MHz to 3700 MHz.
Description
Mobile broadband is the marketing term for wireless Internet access delivered through cellular towers to computers and other digital devices using portable modems. Although broadband has a technical meaning, wireless-carrier marketing uses the phrase "mobile broadband" as a synonym for mobile Internet access. Some mobile services allow more than one device to be connected to the Internet using a single cellular connection using a process called tethering.
The bit rates available with Mobile broadband devices support voice and video as well as other data access. Devices that provide mobile broadband to mobile computers include:
PC cards, also known as PC data cards, and Express cards
Mini PCI and Mini PCI Express cards that are integrated into the laptop
USB and mobile broadband modems, also known as connect cards
portable devices with built-in support for mobile broadband, such as laptops, smartphones/tablets, PDAs, and other mobile Internet devices.
Internet access subscriptions are usually sold separately from mobile service subscriptions.
Generations
Roughly every ten years, new mobile network technology and infrastructure involving a change in the fundamental nature of the service, non-backwards-compatible transmission technology, higher peak data rates, new frequency bands, and/or wider channel frequency bandwidth in Hertz, becomes available. These transitions are referred to as generations. The first mobile data services became available during the second generation (2G).
The download (to the user) and upload (to the Internet) data rates given above are peak or maximum rates and end users will typically experience lower data rates.
WiMAX was originally developed to deliver fixed wireless service with wireless mobility added in 2005. CDPD, CDMA2000 EV-DO, and MBWA are no longer being actively developed.
Coverage
In 2011, 90% of the world's population lived in areas with 2G coverage, while 45% lived in areas with 2G and 3G coverage, and 5% lived in areas with 4G coverage. By 2017 more than 90% of the world's population is expected to have 2G coverage, 85% is expected to have 3G coverage, and 50% will have 4G coverage.
A barrier to mobile broadband use is the coverage provided by the mobile service networks. This may mean no mobile network or that service is limited to older and slower mobile broadband technologies. Customers will not always be able to achieve the speeds advertised due to mobile data coverage limitations including distance to the cell tower. In addition, there are issues with connectivity, network capacity, application quality, and mobile network operators' overall inexperience with data traffic. Peak speeds experienced
by users are also often limited by the capabilities of their mobile phone or other mobile device.
Subscriptions and usage
At the end of 2012 there were estimated to be 6.6 billion mobile network subscriptions worldwide (89% penetration), representing roughly 4.4 billion subscribers (many people have more than one subscription). Growth has been around 9% year-on-year. Mobile phone subscriptions were expected to reach 9.3 billion in 2018.
At the end of 2012 there were roughly 1.5 billion mobile broadband subscriptions, growing at a 50% year-on-year rate. Mobile broadband subscriptions were expected to reach 6.5 billion in 2018.
Mobile data traffic doubled between the end of 2011 (~620 Petabytes in Q4 2011) and the end of 2012 (~1280 Petabytes in Q4 2012). This traffic growth is and will continue to be driven by large increases in the number of mobile subscriptions and by increases in the average data traffic per subscription due to increases in the number of smartphones being sold, the use of more demanding applications and in particular video, and the availability and deployment of newer 3G and 4G technologies capable of higher data rates. Total mobile broadband traffic was expected to increase by a factor of 12 to roughly 13,000 PetaBytes by 2018 .
On average, a mobile laptop generates approximately seven times more traffic than a smartphone (3 GB vs. 450 MB/month). This ratio was forecast to fall to 5 times (10 GB vs. 2 GB/month) by 2018. Traffic from mobile devices that tether (share the data access of one device with multiple devices) can be up to 20 times higher than that from non-tethering users and averages between 7 and 14 times higher.
It has also been shown that there are large differences in subscriber and traffic patterns between different provider networks, regional markets, device and user types.
Demand from emerging markets has fuelled growth in both mobile device and mobile broadband subscriptions and use. Lacking widespread fixed-line infrastructure, many emerging markets use mobile broadband technologies to deliver affordable high-speed internet access to the mass market.
One common use case of mobile broadband is among the construction industry.
Development
In use and under active development
GSM family
In 1995 telecommunication, mobile phone, integrated-circuit, and laptop computer manufacturers formed the GSM Association to push for built-in support for mobile-broadband technology on notebook computers. The association established a service mark to identify devices that include Internet connectivity. Established in early 1998, the global Third Generation Partnership Project (3GPP) develops the evolving GSM family of standards, which includes GSM, EDGE, WCDMA/UMTS, HSPA, LTE and 5G NR. In 2011 these standards were the most used method to deliver mobile broadband. With the development of the 4G LTE signalling standard, download speeds could be increased to 300Β Mbit/s per second within the next several years.
IEEE 802.16 (WiMAX)
The IEEE working group IEEE 802.16, produces standards adopted in products using the WiMAX trademark. The original "Fixed WiMAX" standard was released in 2001 and "Mobile WiMAX" was added in 2005. The WiMAX Forum is a non-profit organization formed to promote the adoption of WiMAX compatible products and services.
In use, but moving to other protocols
CDMA family
Established in late 1998, the global Third Generation Partnership Project 2 (3GPP2) develops the evolving CDMA family of standards, which includes cdmaOne, CDMA2000, and CDMA2000 EV-DO. CDMA2000 EV-DO is no longer being developed.
IEEE 802.20
In 2002, the Institute of Electrical and Electronics Engineers (IEEE) established a Mobile Broadband Wireless Access (MBWA) working group. They developed the IEEE 802.20 standard in 2008, with amendments in 2010.
Edholm's law
Edholm's law in 2004 noted that the bandwidths of wireless cellular networks have been increasing at a faster pace compared to wired telecommunications networks. This is due to advances in MOSFET wireless technology enabling the development and growth of digital wireless networks. The wide adoption of RF CMOS (radio frequency CMOS), power MOSFET and LDMOS (lateral diffused MOS) devices led to the development and proliferation of digital wireless networks in the 1990s, with further advances in MOSFET technology leading to rapidly increasing network bandwidth since the 2000s.
See also
References
External links
GSM Association, official website for the worldwide trade group representing GSM operators
3GPP official website
3GPP2 official website
Mobile broadband | Mobile broadband | [
"Technology"
] | 1,609 | [
"Mobile telecommunications",
"Mobile broadband"
] |
8,879,132 | https://en.wikipedia.org/wiki/List%20of%20traditional%20territories%20of%20the%20Indigenous%20peoples%20of%20North%20America | A Traditional Territory comprises all of the lands which an Indigenous nation ever claimed, not just the present-day Reservation. This article is about the name for the traditional territory (the land) itself, rather than the name of the nation/tribe/people. The distinction between nation and land is like the French people versus the land of France, the MΔori people versus the land of Aotearoa, or the Saami people versus the land of SΓ‘pmi (Saamiland). For example, the traditional territory of the Ho-Chunk (Winnebago) Nation is called Waaziija, meaning "the Grand Pinery."
In English, the land of an indigenous nation was historically, and sometimes still is, referred to as a "country," such as "(the) Winnebago country." Some Latinate forms exist in English such as "Iroquoia", "Huronia", and "Apacheria."
List of traditional territories
Criteria for inclusion
For the purpose of this list, "nation" refers to the historic, whole national identities, rather than to the fragmented "reservation nations" or "bands". The whole nations are what John Beaucage, Grand Council Chief of the Anishinabek Nation, refers to as "true nations" in contrast with the fragmented "First Nations":
Or what the Government of Quebec calls "the 11 aboriginal nations of QuΓ©bec" in contrast with their component "55 aboriginal communities".
And so the criteria for inclusion is not the same as what are named "Indian tribes" by the U.S. Federal Register and the National Congress of American Indians (NCAI), or what are called "First Nations" by the Canadian government and Assembly of First Nations (AFN). It would be interesting to compile the names for the "band territories" of the 633 fragmented First Nations of the AFN, or the names of the "reservation territories" of the 632 fragmented Indian Nations of the NCAI, but that is beyond the scope of this article, except as side notes in the "further information" column.
So this list does not include the names for reservations or reserves, but only of the entire national homeland (or the homeland of a confederated identity such as the Haudenosaunee Confederacy or Colville tribes). For example, this list wouldn't give the Cherokee name for the Qualla Boundary reservation, but only the name for "the Cherokee country" as a whole. Ideally a single name could conceivably encompass not only the Contact-era ancestral territory, but also any area which at some time or another was conceived to be part of the national domain, such as post-Removal lands.
The names do not have to be from olden days. The names could be recently coined and still be included in this list.
Compiling a list such as this can be a difficult and controversial process, as it requires some discernment as to what are the "whole nations" β the "true nations" in Beaucage's words.
Notes
References
North America, Traditional territories of the indigenous peoples
Indigenous peoples of North America
History of Indigenous peoples of North America
Lists of countries in North America
Indigenous peoples in Canada-related lists
Native American-related lists | List of traditional territories of the Indigenous peoples of North America | [
"Environmental_science"
] | 664 | [
"Environmental social science",
"Human geography"
] |
8,879,537 | https://en.wikipedia.org/wiki/Hybrid%20Scheduling | Hybrid Scheduling is a class of scheduling mechanisms that mix different scheduling criteria or disciplines in one algorithm. For example, scheduling uplink and downlink traffic in a WLAN (Wireless Local Area Network, such as IEEE 802.11e) using a single discipline or framework is an instance of hybrid scheduling. Other examples include a scheduling scheme that can provide differentiated and integrated (guaranteed) services in one discipline. Another example could be scheduling of node communications where centralized communications and distributed communications coexist. Further examples of such schedulers are found in the following articles:
References
1- Y. Pourmohammadi Fallah, H. Alnuweiri,"Hybrid Polling and Contention Access Scheduling in IEEE 802.11e WLANs", Journal of Parallel and Distributed Computing, Elsevier, Vol 67, Issue 2, Feb. 2007, pp.Β 242β256.
Computer networking | Hybrid Scheduling | [
"Technology",
"Engineering"
] | 179 | [
"Computer networking",
"Computer engineering",
"Computer network stubs",
"Computer science",
"Computing stubs"
] |
8,880,387 | https://en.wikipedia.org/wiki/Programming%20by%20example | In computer science, programming by example (PbE), also termed programming by demonstration or more generally as demonstrational programming, is an end-user development technique for teaching a computer new behavior by demonstrating actions on concrete examples. The system records user actions and infers a generalized program that can be used on new examples.
PbE is intended to be easier to do than traditional computer programming, which generally requires learning and using a programming language. Many PbE systems have been developed as research prototypes, but few have found widespread real-world application. More recently, PbE has proved to be a useful paradigm for creating scientific work-flows. PbE is used in two independent clients for the BioMOBY protocol: Seahawk and Gbrowse moby.
Also the programming by demonstration (PbD) term has been mostly adopted by robotics researchers for teaching new behaviors to the robot through a physical demonstration of the task. The usual distinction in literature between these terms is that in PbE the user gives a prototypical product of the computer execution, such as a row in the desired results of a query; while in PbD the user performs a sequence of actions that the computer must repeat, generalizing it to be used in different data sets. For final users, to automate a workflow in a complex tool (e.g. Photoshop), the most simple case of PbD is the macro recorder.
See also
Query by Example
Automated machine learning
Example-based machine translation
Inductive programming
Lapis (text editor), which allows simultaneous editing of similar items in multiple selections created by example
Programming by demonstration
Test-driven development
References
External links
Henry Lieberman's page on Programming by Example
Online copy of Watch What I Do, Allen Cypher's book on Programming by Demonstration
Online copy of Your Wish is My Command, Henry Lieberman's sequel to Watch What I Do
A Visual Language for Data Mapping, John Carlson's description of an Integrated Development Environment (IDE) that used Programming by Example (desktop objects) for data mapping, and an iconic language for recording operations
User interfaces
Programming paradigms
Machine learning | Programming by example | [
"Technology",
"Engineering"
] | 432 | [
"User interfaces",
"Machine learning",
"Computer science stubs",
"Computer science",
"Interfaces",
"Artificial intelligence engineering",
"Computing stubs"
] |
8,881,272 | https://en.wikipedia.org/wiki/IF%20Product%20Design%20Award | The iF Product Design Award was introduced in 1954 and is annually conferred by the iF International Forum Design. The award, which spans multiple disciplines, has more than 5,500 entries from around 59 nations every year.
History
The iF Industrie Forum Design e.V. launched in 1953 with a "Special Show for Well-Designed Industrial Goods" as part of the Hanover Fair industrial trade exhibition, originally to highlight German Design. They now strive to serve as a mediating arm between design and industry internationally, believing that this capacity allows them to make contributions to design services and to increase public awareness on the importance of design. In 2000-2002 they combined all relevant areas in design, some with previous award programs they had started, to become the iF Design Award. Today the contest attracts entries from more than 50 countries, in 6 disciplines spanning 70 categories. To this day, iF International Forum Design publishes annual yearbooks showcasing the winners of their design awards.
Community
The iF Industrial Forum Design is joined by other design professional organizations around the world to increase public awareness about design. Designers who are members of Industrial Designers Society of America (IDSA), Verband Deutscher Industrie Designer e.V. (VDID), and International Council of Societies of Industrial Design (ICSID) are just a few of the international community that enter the iF Product Design competition.
iF Design Winners
Iskradata 1680, (1981)
Waterson Self-Closing Swing Clear Hinge, (2023)
THE ANALOG THING, (2024)
Disciplines and categories
Product [Sub-Categories: Automotive, Sports/outdoor/Bicycles, Leisure, Kids, Jewelry, Audio, TV/Cameras, Telecommunication, Computer, VR/Gaming, Office, Lighting, Home furniture, Kitchen, Household, Bathroom, Garden, Building technology, Retail, Healthcare, Industry, and Textiles]
Packaging [Contains 8 Sub-Categories]
Communication [Contains 9 Sub-Categories]
Interior Architecture [Contains 8 Sub-Categories]
Professional Concept [Contains 10 Sub-Categories]
Service Design / UX [Contains 8 Sub-Categories]
Architecture [Contains 6 Sub-Categories]
References
Further reading
IF International Forum Design, (2009), iF Yearbook Product 2009, Birkhauser Basel,
IF International Forum Design, (2009), iF Yearbook Product 2008, Birkhauser Basel,
IF International Forum Design, (2008), iF Yearbook Communication 2008, Birkhauser Basel,
IF International Forum Design, (2007), iF Yearbook Product 2007, Birkhauser Basel,
IF International Forum Design, (2007), iF Yearbook Communication 2007, Birkhauser Basel,
IF International Forum Design, (2006), iF Yearbook Product 2006, Birkhauser Basel,
IF International Forum Design, (2006), iF Yearbook Communication 2006, Birkhauser Basel,
IF International Forum Design, (2005), iF Yearbook Product 2005, Birkhauser Basel,
IF International Forum Design, (2005), iF Yearbook Communication 2005, Birkhauser Basel,
IF International Forum Design, (2004), iF Yearbook 2004, Birkhauser Basel,
IF International Forum Design, (2004), iF Yearbook Communication 2004, Birkhauser Basel,
IF International Forum Design, (2003), iF Yearbook 2003, Birkhauser Basel,
External links
1954 establishments in Germany
Awards established in 1954
Industrial design awards
Product design | IF Product Design Award | [
"Engineering"
] | 685 | [
"Product design",
"Design"
] |
8,881,415 | https://en.wikipedia.org/wiki/Stevens%20Award | The Stevens Award is a software engineering lecture award given by the Reengineering Forum, an industry association. The international Stevens Award was created to recognize outstanding contributions to the literature or practice of methods for software and systems development. The first award was given in 1995. The presentations focus on the current state of software methods and their direction for the future.
This award lecture is named in memory of Wayne Stevens (1944-1993), a consultant, author, pioneer, and advocate of the practical application of software methods and tools. The Stevens Award and lecture is managed by the Reengineering Forum. The award was founded by International Workshop on Computer Aided Software Engineering (IWCASE), an international workshop association of users and developers of computer-aided software engineering (CASE) technology, which merged into The Reengineering Forum. Wayne Stevens was a charter member of the IWCASE executive board.
Recipients
1995: Tony Wasserman
1996: David Harel
1997: Michael Jackson
1998: Thomas McCabe
1999: Tom DeMarco
2000: Gerald Weinberg
2001: Peter Chen
2002: Cordell Green
2003: Manny Lehman
2004: François Bodart
2005: Mary Shaw, Jim Highsmith
2006: Grady Booch
2007: Nicholas Zvegintzov
2008: Harry Sneed
2009: Larry Constantine
2010: Peter Aiken
2011: Jared Spool, Barry Boehm
2012: Philip Newcomb
2013: Jean-Luc Hainaut
2014: François Coallier
2015: Pierre Bourque
See also
List of computer science awards
References
Computer science awards
Software engineering | Stevens Award | [
"Technology",
"Engineering"
] | 316 | [
"Systems engineering",
"Computer science awards",
"Computer engineering",
"Software engineering",
"Computer science",
"Information technology",
"Science and technology awards"
] |
8,881,705 | https://en.wikipedia.org/wiki/List%20of%20vacuum%20tubes | This is a list of vacuum tubes or thermionic valves, and low-pressure gas-filled tubes, or discharge tubes. Before the advent of semiconductor devices, thousands of tube types were used in consumer electronics. Many industrial, military or otherwise professional tubes were also produced. Only a few types are still used today, mainly in high-power, high-frequency applications.
Heater or filament ratings
Receiving tubes have heaters or filaments intended for direct battery operation, parallel operation off a dedicated winding on a supply transformer, or series string operation on transformer-less sets. High-power RF power tubes are directly heated; the heater voltage must be much smaller than the signal voltage on the grid and is therefore in the 5...25Β V range, drawing up to hundreds of amperes from a suitable heater transformer. In some valve part number series, the voltage class of the heater is given in the part number, and a similar valve might be available with several different heater voltage ratings.
Tube bases and envelopes
Abbreviations used in this list
ST β Shouldered tube
GT β Glass tube
MT β Miniature tube, such as Noval B9A or Miniature 7-pin B7G
FL β Subminiature all-glass elliptical body and flat bases with long, inline "flying leads" (wire-ends) that are soldered into the circuit
SL β Subminiature all-glass elliptical body and flat bases with short inline leads that can be soldered or can be mated with a special socket. (Flying leads can be cut short to fit into inline sockets.)
R8 β Subminiature all-glass round body and base with 8 flying leads or stiff pins arranged in a circle
Numbering systems
North American systems
RETMA receiving tubes system
RETMA is the acronym for the Radio Electronic Television Manufacturers Association formed in 1953 - however the standard itself had already been in use since 1933, when RCA/Cunningham introduced the 1A6, 2A3, 2A5, etc.
The first character group is a number representing the heater voltage rounded to the nearest whole number; 0 indicates a cold-cathode tube.
One or two letters assigned to the devices in order of development.
A single numeral that represents the number of active elements in the tube.
Suffix letters distinguish revisions or variants:
A, B, C β Improved backward compatible versions
E β Export version
G β Glass bulb, ST-12 to ST-16 size
GT β Glass bulb, T-9 size
GT/G β Glass bulb, T-9 size interchangeable with G and GT types
L β Loctal
LM β Loctal-metal
LT β Locking base
M β Metal envelope
MG β Metal-glass
ML β Metal-Loctal
S β Spray shielded
W β Ruggedised, or military grade
WA, WB β Improved, backward compatible military/industrial variants
X β Low loss ceramic base for RF use
Y β Low loss mica-filled phenolic resin ("Micanol") base for RF use
Lastly, manufacturers may decide to combine two type numbers into a single name, which their one device can replace, such as: 6DX8/ECL84 (6DX8 and ECL84 being identical devices under different naming schemes) or 6BC5/6CE5 (sufficiently identical devices within the RETMA naming system) and even 3A3/3B2, or 6AC5-GT/6AC5-G (where the single type number, 6AC5-GT/6AC5-G, supersedes both the 6AC5-G and the 6AC5-GT).
Often designations that differed only in their initial numerals would be identical except for heater characteristics.
For examples see below
RMA professional tubes system
The system was used in 1942β44 and assigned numbers with the base form "1A21", and is therefore also referred to as the "1A21 system".
The first numeric character indicated the filament/heater power rating, the second alphabetic character was a code for the function, and the last 2 digits were sequentially assigned, beginning with 21
For examples see below.
EIA professional tubes system
A four-digit system was maintained by JETEC since 1944, then by EIA since 1957 for special industrial, military and professional vacuum and gas-filled tubes, and all sorts of other devices requiring to be sealed off against the external atmosphere.
Some manufacturers preceded the EIA number with a manufacturer's code:
CK, RK β Raytheon Company
ECG β Philips/Sylvania
F β Federal Telephone and Radio (ITT division)
GL β General Electric Corp. (not British General Electric Company)
ML β Machlett Laboratories, Inc.
NL β National Electronics, Inc. (Geneva, Illinois, USA)
NU β National Union Electric Corp. (Orange, New Jersey, USA)
PL β Philips N.V.
SV β Svetlana:
formerly only PJSC "Svetlana/ΠΠΠ Π‘Π²Π΅ΡΠ»Π°Π½Π°", St. Petersburg, Russia
now also a brand of New Sensor Corp., Long Island City, New York, USA, manufacturing in Saratov, Russia
WL β Westinghouse Electric Corp.
For examples see below.
Eimac transmitting tubes system
Eitel/McCullough and other manufacturers of high power RF tubes use the following code since 1945:
An initial digit denoting the number of electrodes:
2 β Diode
3 β Triode
4 β Tetrode
5 β Pentode
Up to 2 letters denoting the construction type and the cooling method:
R or a dash ("-") β Glass envelope, radiation cooling
C β Ceramic envelope
K β (Reflex-)Klystron
P β Primarily for pulse applications
L β External anode, liquid convection cooling
N β External anode, natural convection air cooling
S β External anode, conduction cooling
V β Vapor cooled (anode is immersed in boiling water, and the steam is collected, condensed and recycled)
W β Water cooled (water is pumped through an outer metal jacket thermically connected to the anode)
X β Forced-air cooled (air is blown through cooling fins thermally connected to the anode)
A number to indicate the maximum anode dissipation in watts. This can be exceeded for a short time, as long as the average is not exceeded over the anode's thermal time constant (typically 0.1 sec). In Class-C applications, the amplifier output power delivered to the load may be higher than the device dissipation
One or more manufacturer-proprietary letters denoting the construction variant
An optional digit denoting the gain group:
1 β β€10
2 β 11...20
3 β 21...30
4 β 31...50
5 β 51...100
6 β 101...200
7 β 201...500
8 β 501...1000
Optionally a slash "/" followed by the RMA or EIA equivalent.
Examples:
3CW5000A3 β 5Β kW Ceramic triode, water cooled, variant 'A', gain group 3
3CX100A5 β 100Β W Ceramic UHF triode, forced-air cooled, variant 'A', gain group 5; often used by radio amateurs for 23cm-band microwave amplifiers.
3CX1500A7 (8877) β 1.5Β kW Ceramic triode, forced air cooled, variant 'A', gain group 7
3CX2500A3 β 2.5Β kW Ceramic triode, forced air cooled, variant 'A', gain group 3
4-65A (8165) β 65Β W Glass beam tetrode
4-125A (4D21, 6155) β 125Β W Glass beam tetrode
4-250A (5D22, 6156) β 110Β MHz, 250Β W Glass beam tetrode
4-400A β 400Β W Glass beam tetrode
4-1000A (8166) β 1Β kW Glass beam tetrode popular in broadcast and amateur transmitters.
4CX250B β 250Β W Ceramic tetrode, forced-air cooled, version 'B', favored by radio amateurs as a final amplifier.
4CX250BC β 250Β W Ceramic tetrode, forced-air cooled, version 'BC'
4CX35000 β Ceramic tetrode used in numerous 50-kW broadcast transmitters, forced-air cooled, often in a Doherty configuration as in the Continental Electronics 317C series.
5-125B/4E27A β 75Β MHz, 125Β W Glass power pentode
5-500A β 500Β W Glass radial-beam pentode
5CX1500A β 110Β MHz, 1.5Β kW Ceramic radial-beam pentode, forced air cooled
5CX3000A β 150Β MHz, 4.0Β kW Ceramic radial-beam pentode, forced air cooled
5K70SH β 30Β kW S-band Klystron
West European systems
MullardβPhilips system
This system is very descriptive of what type of device (triode, diode, pentode etc.) it is applied to, as well as the heater/filament type and the base type (octal, noval, etc.). Adhering manufacturers include AEGΒ (de), AmperexΒ (us), CdLΒ (1921,Β FrenchΒ MazdaΒ brand), CIFTEΒ (fr,Β Mazda-BelvuΒ brand), EdiSwanΒ (uk,Β BritishΒ MazdaΒ brand), RadiotechniqueΒ (fr,Β Coprim,Β Miniwatt-DarioΒ andΒ RTCΒ brands), LorenzΒ (de), MBLE(fr,Β nl) (be,Β Adzam brand), MullardΒ (uk), PhilipsΒ (nl,Β MiniwattΒ brand), RCAΒ (us), RFT(de,Β sv)Β (de), SiemensΒ (de), TelefunkenΒ (de), TeslaΒ (cz), ToshibaΒ (ja), TungsramΒ (hu), UnitraΒ (pl, Dolam, Polam and Telam brands) and Valvo(de,Β it)Β (de).
Standard tubes
This part dates back to the joint valve code key () negotiated between Philips and Telefunken in 1933β34. Like the North American system the first symbol describes the heater voltage, in this case, a Roman letter rather than a number. Further Roman letters, up to three, describe the device followed by one to four numerals assigned in a semi-chronological order of type development within number ranges assigned to different base types.
If two devices share the same type designation other than the first letter (e.g. ECL82, PCL82, UCL82) they will usually be identical except for heater specifications; however there are exceptions, particularly with output types (for example, both the PL84 and UL84 differ significantly from the EL84 in certain major characteristics, although they have the same pinout and similar power rating). However, device numbers do not reveal any similarity between different type families; e.g. the triode section of an ECL82 is not related to either triode of an ECC82, whereas the triode section of an ECL86 does happen to be similar to those of an ECC83.
Pro Electron maintained a subset of the M-P system after their establishment in 1966, with only the first letters E, P for the heater, only the second letters A, B, C, D, E, F, H, K, L, M, Y, Z for the type, and issuing only three-digit numbers starting with 1, 2, 3, 5, 8, 9 for the base.
Notes: Tungsram preceded the M-P designation with the letter T, as in TAD1 for AD1; VATEA RΓ‘diΓ³technikai Γ©s VillamossΓ‘gi Rt.-t. (VATEA Radio Technology and Electric Co. Ltd., Budapest, Hungary) preceded the M-P designation with the letter V, as in VEL5 for EL5.
First letter: heater/filament type
Heater ratings for series-string, AC/DC tubes are given in milliamperes; heater ratings for parallel-string tubes are given in volts
A β 4Β V heater for 2-cell lead-acid batteries and for AC mains transformers
B β 180Β mA DC series heater
C β 200Β mA AC/DC series heater
D β 1.4Β V DC filament for LeclanchΓ© cells, later low-voltage/low power filament/heater:
0.625Β V DC directly heated for NiCd battery, series-heated two-tube designs such as hearing aids. If either filament breaks, further draining of all batteries stops
Wide range 0.9Β V to 1.55Β V DC directly heated for dry cells
1.25Β V DC directly heated for NiCd batteries
1.25Β V or 1.4Β V AC from a separate heater winding on CRT horizontal-output transformers, in half-indirectly heated EHT rectifiers
E β 6.3Β V parallel heater; for 3-cell lead-acid vehicle crank batteries (mobile equipment) and for AC mains or horizontal-output transformers
F β 12.6Β V DC parallel heater for 6-cell lead-acid vehicle crank batteries
G β Various heaters between 2.5 and 5.0Β V AC (except 4Β V) from a separate heater winding on a mains or horizontal-output transformer for the anode voltage rectifier
H β 150Β mA AC/DC series heater
Until at least 1938: 4Β V battery (as opposed to A for "4Β V AC"; no known examples assigned)
I β 20Β V heater
K β 2.0Β V filament for 1-cell lead-acid batteries, later for AC transformers
L β 450Β mA AC/DC series heater; was shifted here from Y
M β 1.9Β V, directly heated
N β 12.6Β V, indirectly heated
O β Cold cathode
by 1955 this also included semiconductors as these had no heater
Philips sold a family of 150mA series heater tubes under this letter in South America
P β 300Β mA AC/DC series heater
Q β 2.4Β V, indirectly heated
R β Not assigned to avoid any confusion with the older Telefunken "R" system
S β 1.9Β V, indirectly heated
T β Custom heater
U β 100Β mA AC/DC series heater
V β 50Β mA AC/DC series heater
X β 600Β mA AC/DC series heater
Y β 450Β mA AC/DC series heater, shifted to L to avoid conflicts with the professional tubes system
Z β Cold cathode tube; was shifted here from O after the advent of semiconductors
Second and subsequent letters: system type
<none> or R β Resistive element (ballast tube, barretter, photoresistor)
A β Small signal diode
B β Dual small signal diode
C β Small signal triode
D β Power output triode
E β Small signal tetrode
F β Small signal pentode
H β Mixer hexode, special purpose heptode
K β Mixer heptode or octode
L β Power output, beam tetrode or pentode
M β Optical tuning/level indicator
N β Noble-gas Thyratron
P β Secondary emission tube β mostly used as third letter
Q β Nonode
S β Special tube ()
T β Beam deflection tube, or misc.
W β Gas-filled half-wave rectifier
X β Gas-filled full-wave rectifier
Y β Vacuum half-wave rectifier (power diode)
Z β Vacuum full-wave rectifier (dual power diode with common cathode)
Following digits: model number and base type
For signal pentodes, an odd model number most often identified a variable-mu (remote-cutoff) tube, whereas an even number identified a 'high slope' (sharp-cutoff) tube
For power pentodes and triode-pentode combinations, even numbers usually indicate linear (audio power amplifier) devices while odd numbers were more suited to video signals or situations where more distortion could be tolerated.
1β9 β Pinch-type construction tubes, mostly P8A side-contact 8-pin bases (P base) or V5A side-contact 5-pin (V base) and various other European pre-octal designs
10β19 β Y8A 8-pin steel tube base, aka "German metal octal"
20β29 β Loctal B8G; some octal; some 8-way side contact (exceptions are DAC21, DBC21, DCH21, DF21, DF22, DL21, DLL21, DM21 which have octal bases)
30β39 β International Octal (IEC 67-I-5a), also known as IO or K8A
40β49 β Rimlok (Rimlock) B8A All-glass miniature tubes
41w β Battery-heated cup tube ()
50β59 β "Special construction types fitted with bases applicable to design features used"; mostly locking bases: "9-pin Loctal" (B9G) or 8-pin Loctal (B8G); but also used for Octal and others (3-pin glass; Disk-seal incl. Lighthouse tubes; German 10-pin with spigot; min. 4-pin; B26A; Magnoval B9D)
60β69 β Pencil tubes β sub-miniature all-glass tubes, wire-ended (inline fly-leads in place of pins)
βBefore the 1950s:
60β64 β All-glass tubes fitted with 9-pin Loctal (B9G) bases
70β79 β Pencil tubes with circular pins or fly-leads
βBefore the 1950s:
70β79 β 8-pin Loctal (Lorenz)
80β89 β Noval B9A (9-pin; IEC 67-I-12a)
90β99 β "Button" B7G (miniature 7-pin; IEC 67-I-10a)
100β109 β B7G; Wehrmacht base; German PTT base
110β119 β Y8A 8-pin steel tube base; Rimlock B8A
130β139 β Octal
150β159 β German 10-pin with spigot; 10-pin glass with one big pin; Octal
160β169 β Inline wire-ended Pencil tubes; Y8A 8-pin steel tube base
170β179 β RFT 8-pin; RFT 11-pin all-glass gnome tube with one offset pin
180β189 β Noval B9A
190β199 β Miniature 7-pin B7G
200β209 β Decal B10B
230β239 β Octal
270β279 β RFT 11-pin all glass with one offset pin
280β289 β Noval B9A
300β399 β Octal
400β499 β Rimlock B8A
500β529 β Magnoval B9D
600β699 β Inline wire-ended Pencil tubes
700β799 β Circular wire-ended Pencil tubes
800β899 β Noval B9A
900β999 β Miniature 7-pin B7G
βSpecial quality:
1000β Round wire-ended; special Nuvistor base
2000β Decal B10B
3000β Octal
5000β Magnoval B9D
8000β Noval B9A
For examples see below
Special quality tubes
Vacuum tubes which had special qualities of some sort, very often long-life designs, particularly for computer and telecommunications use, had the numeric part of the designation placed immediately after the first letter. They were usually special-quality versions of standard types. Thus the E82CC was a long-life version of the ECC82 intended for computer and general signal use, and the E88CC a high quality version of the ECC88/6DJ8. While the E80F pentode was a high quality development of the EF80, they were not pin-compatible and could not be interchanged without rewiring the socket (the E80F is commonly sought after as a high quality replacement for the similar EF86 type in guitar amplifiers). The letters "CC" indicated the two triodes and the "F", the single pentode inside these types.
A few special-quality tubes did not have a standard equivalent, e.g. the E55L, a broadband power pentode used as the output stage of oscilloscope amplifiers and the E90CC, a dual triode with a common cathode connection and seven pin base for use in cathode-coupled Flip-flops in early computers. The E91H is a special heptode with a passivated third grid designed to reduce secondary emission; this device was used as a "gate", allowing or blocking pulses applied to the first, (control) grid by changing the voltage on the third grid, in early computer circuits (similar in function to the U.S. 6AS6).
Many of these types had gold-plated base pins and special heater configurations inside the nickel cathode tube designed to reduce hum pickup from the A.C. heater supply, and also had improved oxide insulation between the heater and cathode so the cathode could be elevated to a greater voltage above the heater supply. (Note that elevating the cathode voltage above the average heater voltage, which in well-designed equipment was supplied from a transformer with an earthed center-tapped secondary, was less detrimental to the oxide insulation between heater and cathode than lowering the cathode voltage below the heater voltage, helping to prevent pyrometallurgical electrolytic chemical reactions where the oxide touched the nickel cathode that could form conductive aluminium tungstate and which could ultimately develop into a heater-cathode short circuit.)
Better, often dual, getters were implemented to maintain a better vacuum, and more-rigid electrode supports introduced to reduce microphonics and improve vibration and shock resistance. The mica spacers used in "SQ" and "PQ" types did not possess sharp protrusions which could flake off and become loose inside the bulb, possibly lodging between the grids and thus changing the characteristics of the device. Some types, particularly the E80F, E88CC and E90CC, had a constricted section of bulb to firmly hold specially shaped flakeless mica spacers.
For examples see below, starting at DC
Later special-quality tubes had not base and function swapped but were assigned a 4-digit number, such as ECC2000 or ED8000, the first digit of which again denoting the base:
1 β Miscellaneous
2 β 10-pin Decal base (JEDEC E10-61)
3 β Octal base (IEC 67-1-5a)
5 β Magnoval base (JEDEC E9-23)
8 β Noval base (IEC 67-1-12a)
9 β Miniature 7-pin base (IEC 67-1-10a)
For examples see below, starting at EC
"Z" Cold-cathode SQ tubes had a different function letter scheme:
A β Arc discharge tube
B β Binary counter or switching tube
C β Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading
E β Electrometer tube
G β Gating tube
M β Optical indicator
S β Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc.
T β Relay triode, a low-power triode thyratron, one starter electrode, may need illumination for proper operation if not radioactively primed
U β Low-power tetrode thyratron, may mean:
Trigger tetrode, one starter electrode and a primer (keep-alive) electrode for ion availability to keep the ignition voltage constant, for analog RC timers, voltage triggers, etc.
Relay tetrode, two starter electrodes to make counters bidirectional or resettable
W β Trigger pentode, two starter electrodes and a primer electrode
X β Shielded Trigger pentode, two starter electrodes, a primer electrode and a conductive coating of the glass envelope inside connected to a separate pin
For examples, see below under Z
Professional tubes
In use since at least 1961, this system was maintained by Pro Electron after their establishment in 1966.
Both letters together indicate the type:
X β High vacuum electro-optical devices
XA β Phototube
XG β Miscellaneous
XM β Character generating cathode ray tube
XP β Photomultiplier
XQ β Camera tube
XR β Monoscope
XS β Cathode ray charge storage tube
XT β Memory display tube
XV β Infrared detector
XW β Infrared imaging device
XX β Image intensifier or image converter
Y β Vacuum tubes
YA β Diode
YD β Transmitting or industrial, single or dual triode
YG β Electrometer tube, vacuum gauge
YH β Traveling-wave tube
YJ β Magnetron
YK β Klystron
YL β Transmitting or industrial, single or dual tetrode or pentode
YN β Backward-wave oscillator
YP β Electron multiplier
YR β Crossed-field amplifier
YT β Pulse modulator tube
YY β High vacuum rectifier
Z β Gas-filled tubes not employing photosensitive materials
ZA β Cold cathode indicator tube
ZB β Microwave switching tube (TR/ATR cells, etc.)
ZC β Trigger tube
ZD β Surge arrester
ZE β Glow modulator tube, a linear light source for rotating-drum FAX receivers, film soundtrack recording, etc.
ZF β Flash tube
ZL β Gas laser
ZM β Cold cathode character display tube or counter display tube
ZP β Radiation counter tube (Geiger-MΓΌller counter tube or proportional counter tube)
ZQ β Mixed analogue and digital display
ZR β Plasma display panel
ZS β Bar graph
ZT β Thyratron
ZX β Ignitron
ZY β Mercury-vapor rectifier
ZZ β Voltage stabilizer or corona discharge tube
Then follows a 4-digit sequentially assigned number.
Optional suffixes for camera tubes:
Version letter:
B β Blue
G β Green
L β Luminance
R β Red
T β Reticule
X β Medical X-ray
Letter for variants derived by selection:
D β High resolution
M β Blemish standard
For examples see below
Transmitting tubes
The first letter (or letter pair, in the case of a dual-system device) indicates the general type:
B β Backward-wave amplifier
D β Rectifier, including grid-controlled types
J β Magnetron
K β Klystron
L β Traveling-wave tube
M β Triode (AF amplifier or modulator)
P β Pentode
Q β Tetrode
R β Rectifier, including grid-controlled types
T β Triode (RF, oscillator)
X β Large thyratron (including all hydrogen thyratrons and high-current types)
The following letter indicates the filament or cathode type, or the fill gas or other construction detail. The coding for vacuum devices differs between Philips (and other Continental European manufacturers) on the one hand and its Mullard subsidiary on the other.
Philips vacuum devices:
A
Microwave tubes: Output power <1W
Other tubes: Directly heated tungsten filament
B
Microwave tubes: Output power β₯1W
Other tubes: Directly heated thoriated tungsten filament
C β Directly heated oxide-coated filament
E β Indirectly heated oxide-coated cathode
Mullard vacuum devices:
D β Disk-seal construction
N β External magnet required (magnetrons)
P β Packaged construction (magnetrons)
S β Reflex klystron
T β Multiple resonator (klystrons)
V β Indirectly heated oxide-coated cathode
X β Directly heated tungsten filament
Y β Directly heated thoriated tungsten filament
Z β Directly heated oxide-coated filament (except mercury-vapor rectifiers)
Gas-filled devices:
G β Mercury-vapor filling, directly heated oxide-coated filament
H β Hydrogen filling
R β Rare-gas filling
X β Xenon filling
The next letter indicates the cooling method or other significant characteristic:
H β Helix or other integral cooler
L β Forced-air cooling
Q β Shield-grid (tetrode) thyratron (thyratrons only)
S β Silica envelope, to allow for a glowing anode
T β Tunable microwave device
W β Water cooling
The following group of digits indicate:
Microwave tubes: Frequency in GHz
Rectifying tubes: DC output voltage in kV
Thyratrons: Peak inverse voltage in kV
Transmitting tubes: Maximum anode voltage in kV
The following group of digits indicate the power:
Backward-wave amplifier or Traveling-wave tube: Output power
2nd letter: A β in mW
2nd letter: B β in W
Klystrons: Output power in W
Reflex Klystrons: Output power in mW
Magnetrons: Pulse output power in kW
Continuously transmitting tubes: Maximum anode dissipation in W or kW in Class-C amplifier telegraphy
Pulsed transmitting tubes: Maximum peak anode current in A (number preceded by "P")
Rectifiers: Maximum average anode current in mA
Thyratrons: Maximum average anode current:
Less than 3 digits: in mA
3 or more digits:
1st digit: =0 β in mA
1st digit: >0 β in A
An optional following letter indicates the base or connection method:
B β Cables
E β Medium 7-pin U7A base
ED β Edison screw E27 lamp base
EG β Goliath E40 lamp base
F β 12.6V Heater
G β Medium 4-pin UX4 base
GB β Jumbo 4-pin base
GS β Superjumbo 4-pin base
N β Medium 5-pin UY5 base
P β Side-contact 8-pin base
For examples see below
Phototubes and photomultipliers
The first digit indicates the tube base:
2 β Loctal 8-pin base
3 β Octal base
5, 6 β Special base or flying leads
8 β Noval base
9 β Miniature 7-pin base
The second digit is a sequentially assigned number.
The following letter indicates the photocathode type:
A β Caesium-activated antimony cathode. Used for reflective-mode photocathodes. Response range from ultraviolet to visible. Widely used.
C β Caesium-on-oxidated-silver cathode, also called S1. Transmission-mode, sensitive from 300...1200Β nm. High dark current; used mainly in near-infrared, with the photocathode cooled.
T β Trialkali sodium-potassium-antimony-caesium cathode, wide spectral response from ultraviolet to near-infrared; special cathode processing can extend range to 930Β nm. Used in broadband spectrophotometers.
U β Caesium-antimony cathode with a quartz window
The following letter indicates the filling:
G β Gas-filled
V β High-vacuum
A following letter P indicates a photomultiplier.
Examples:
50AVP β 11-stage photomultiplier for scintillation counters, duodecal base
51UVP β 11-stage photomultiplier, duodecal base
52AVP/XP1180 β 10-stage photomultiplier, 13-pin base
53AVP, 153AVP β 10-stage photomultiplier, diheptal 14-pin base
53UVP β 11-stage photomultiplier, diheptal 14-pin base
54AVP β 11-stage photomultiplier, diheptal 14-pin base
55AVP β 15-stage photomultiplier, bidecal 20-pin base
56AVP β 14-stage photomultiplier, bidecal 20-pin base
56UVP β 14-stage photomultiplier, duodecal base
57AVP β 11-stage photomultiplier, bidecal 20-pin base
58AVP β 14-stage photomultiplier, bidecal 20-pin base
150AVP β 10-stage photomultiplier, bidecal 20-pin base
150CVP β 10-stage photomultiplier, bidecal 20-pin base
57CV β Photometric cell
58CG β Gas-filled phototube, Red/IR sensitive, all-glass wire-ended
58CV β Vacuum phototube, Red/IR sensitive, all-glass wire-ended
90AG β Gas-filled phototube, daylight/blue sensitive, miniature 7-pin base
90AV β Vacuum phototube, blue sensitive, miniature 7-pin base
90CG β Gas-filled phototube, Red/IR sensitive, miniature 7-pin base
90CV β Vacuum phototube, Red/IR sensitive, miniature 7-pin base
92AG β Gas-filled phototube, blue sensitive, miniature 7-pin base
92AV β Vacuum phototube, blue sensitive, miniature 7-pin base
61SV/7634 β PbS infrared (300...3500Β nm) photoresistor, 2-pin all-glass wire-ended
Voltage stabilizers
The first number indicates the burning voltage
The following letter indicates the current range:
A β max. 10mA
B β max. 22mA
C β max. 40mA
D β max. 100mA
E β max. 200mA
The following digit is a sequentially assigned number.
An optional, following letter indicates the base:
E β Edison screw lamp base
K β Octal base
P β Side-contact 8-pin base
Examples:
75B1 β Voltage reference tube, miniature 7-pin base
75C1 β Voltage reference tube, miniature 7-pin base
83A1 β Voltage reference tube, miniature 7-pin base
85A1/0E3 β Voltage reference tube, B8G Loctal base
85A2/0G3 β Voltage reference tube, miniature 7-pin base
90C1 β Voltage reference tube, miniature 7-pin base
95A1 β Voltage reference tube, miniature 7-pin base
100E1 β Voltage reference tube, A4A European 4-pin Base
108C1/0B2 β Voltage reference tube, miniature 7-pin base
150A1 β Voltage reference tube, P8A side-contact 8 base
150B2 β Voltage reference tube, miniature 7-pin base
150B3 β Voltage reference tube, miniature 7-pin base
150C1 β Voltage reference tube, P8A side-contact 8 base
150C2/0A2 β Voltage reference tube, miniature 7-pin base
150C4 β Voltage reference tube, miniature 7-pin base
Compagnie des Lampes (1888, "MΓ©tal") system
The first (1888) incarnation of La Compagnie des Lampes produced the TM tube since 1915 and defined one of the first French systems; not to be confused with Compagnie des Lampes (1921, "French Mazda", see below).
First letter: Heater or filament voltage
A β 1 V
B β 2 V
D β 4 V
E β 5 V
F β 6 V
G β 7 V
Second letter: Heater or filament current
W β β₯200 mA
X β 150 mA
Y β 100...140 mA
Z β <100 mA
Next number: Gain
Next number: Internal resistance in kΞ©
Examples:
BW604 β MΓ©tal secteur indirectly AC-heated AF power triode
BW1010 β MΓ©tal secteur indirectly AC-heated AF triode
EdiSwan ("British Mazda") systems
{| class="wikitable floatright" style="width: 30%;"
|-
| EdiSwan (British Mazda) is not to be confused with other licensees of General Electric's Mazda brand:
GE's own subsidiary British Thomson-Houston
Cie des Lampes (1921, French Mazda, see below)
Cie Industrielle FranΓ§aise des Tubes Electroniques β CIFTE (Mazda-Belvu β originating from SocietΓ© Radio Belvu; see below)
Manufacture Belge des Lampes Γlectriques,(fr, nl) producing:
Light bulbs since 1911 under the Belgian Mazda brand
Electronic tubes since 1924 under the Adzam ("Mazda" spelled backwards) brand
|}
Note: EdiSwan also used the MullardβPhilips scheme.
Signal tubes
First number: Heater or filament rating
0 β Misc. higher voltages
1 β 1.4 V
6 β 6.3 V
10 β 100 mA
20 β 200 mA
30 β 300 mA
Following letter or letter sequence: Type
C β Frequency changer with special oscillator section
D β Signal diode(s)
F β Tetrode or pentode
FD β Tetrode or pentode and diode(s)
FL β Tetrode or pentode, and triode
K β Small gas triode or tetrode thyratron
L β Single or dual triode, including oscillator triode
LD β Triode and diode(s)
M β Optical tuning/level indicator
P β Power tetrode or pentode
PL β Power tetrode or pentode, and signal triode
Final number: Sequentially assigned number
Power tubes
Letter(s): Type
U β High-vacuum half-wave rectifier
UU β High-vacuum full-wave rectifier
Number: Sequentially assigned number
Examples:
Note: "AC/"-series receiver tubes are listed under other letter tubes - AC/
6C10 (6CU7/ECH42) β Triode/hexode frequency converter, Rimlock base
6F22 (6267/EF86) β Low-noise A.F. pentode, noval base
6F33 β Shielded pentode, Miniature 7-pin base
6L12 (6AQ8/ECC85) β Dual triode, noval base
6L19 β Dual triode, Rimlock base
6M2 (6CD7/EM34) β Dual-sensitivity tuning indicator, octal base
6P15 (6BQ5/EL84) β Power pentode, noval base
10PL12 (50BM8/UCL82) β Triode/power pentode, noval base
U381 (38A3/UY85) β Half-wave rectifier, noval base
UU9 (6BT4/EZ40) β Full-wave rectifier, rimlock base
EEV system
This system consists of one or more letters followed by a sequentially assigned number
A β High vacuum rectifier
AFX β Rare-gas filled triode thyratron
AH β Mercury-vapor rectifier
AX β Xenon filled rectifier
B β Radiation-cooled triode
BD β Mercury vapor rectifier
BK β Ignitron
BM β Magnetron
BR β Forced air cooled triode
BS β TR (Transmit/receive) cell, TB cell, Solid-state microwave device
BT β Mercury vapor or xenon filled thyratron
BW β Water cooled triode
BY β Vapor cooled triode
C β Radiation-cooled tetrode
CR β Forced air cooled tetrode
CW β Water cooled tetrode
CX β Hydrogen tetrode thyratron
E β Storage tube
FX β Hydrogen triode thyratron
GX β Spark gap
K β Klystron
M β Magnetron
NFT β Nernst filament, a source of mid-infrared radiation
P β Video camera tube
QS β Voltage-regulator tube
QT β Cold-cathode trigger tube
T β CRT
U β Vacuum capacitor
XL β Glow modulator tube, flash tube, gas laser
Examples:
B142 β 400Β W RF power triode up to 50Β MHz similar to 833A
B1109 = 3C24 β 25Β W VHF power triode up to 60Β MHz
B1135 = 5867 = CV1350 β VHF power triode up to 100Β MHz
B1152 β 500W RF power triode up to 50Β MHz
QT1257 β Touch button tube, an illuminated capacitance touch switch; a cold-cathode DC relay tube, external (capacitive) starter activated by touching; then the cathode glow is visible. 6-pin octal base
XL601, XL602, XL603, XL627, XL628, XL631 and XL632 β Cold-cathode, linear light source (glow modulator tube), gas diode with a blue-violet glow, modulation up to 1Β MHz, 2-pin Octal base, for rotating-drum FAX receivers, etc.
ETL computing tubes system
The British Ericsson Telephones Limited (ETL), of Beeston, Nottingham (not to be confused with the Swedish TelefonAB Ericsson), original holder of the now-generic trademark Dekatron, used the following system:
An initial letter denoting the filling:
G β Noble gas-filled
V β Vacuum
One letter denoting the type:
C β Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading
D β Diode, voltage reference, etc.
R β Register (Readout) β Digital indicator
S β Trochotron or Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc.
TE β Trigger tetrode, one starter electrode and a keep-alive (primer) electrode for ion availability
TR β Trigger triode, one starter electrode only
A digit group:
Dekatrons: Stage count
Digital indicators: Display cathode count
Diodes, voltage references: Nominal voltage
Trigger tubes: Ignition voltage
An optional digit group after a slash: Pin count
One letter denoting the type:
A β Plastic base
B β Plastic base
C β Plastic base
D β Plastic base
E β Plastic base
G β 26-pin B26A base
H β 27-pin B27A base
M β B7G base
P β B7G base
Q β B7G base
W β Wire-ends
X β Wire-ends
Y β Wire-ends
Examples:
GC10/2P β Neon-filled, 1Β kHz Miniature decade Counter Dekatron, a gas-filled, bidirecional decade counter tube
GC10A β Helium-filled, decade Counter Dekatron
GC10B β Neon-filled, 4Β kHz Long life, decade Counter Dekatron
GC10/4B β 4Β kHz Decade Computing Counter Dekatron with carry/borrow cathodes "0" and "9" and intermediate cathodes "3" and "5" wired to separate pins
GC10D β 20Β kHz Decade Counter Dekatron, for single-pulse operation
GC12/4B β 4Β kHz Duodecimal Counter Dekatron with carry/borrow cathodes 11 and 12 and intermediate cathodes 6 and 8 wired to separate pins
GCA10G β 10Β kHz max. Decade Counter Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base without the inner pin ring
GD2V β 2Β kV, 16Β J discharge tube, all-glass studded
GD75P β 75Β V Voltage reference, miniature 7-pin base
GD90M β 90Β V Voltage reference, miniature 7-pin base
GD340X β 345Β V/3...200Β ΞΌA Corona voltage reference, all-glass wire-ended
GD350X, GD350Y β 350Β V/3...200Β ΞΌA Corona voltage reference, all-glass wire-ended
GD550W β 550Β V, 1.5Β J Discharge tube, e.g. for power relaxation oscillators, all-glass wire-ended
GDT120M β 9Β mA Gas-filled cold-cathode DC triode, one starter and a separate glow diode acting as an optical primer, miniature 7-pin base
GR2G β Β + -Β Neon-filled digital indicator tube, 18 x 18Β mm characters, side-viewing
GR2H β Β + -Β Neon-filled digital indicator tube, 20 x 20Β mm characters, top-viewing
GR4G β Β 1Β Neon-filled digital indicator tube, 18 x 30Β mm characters, side-viewing
GR7M β Β + - V A Ξ© % ~Β Neon-filled digital indicator tube, 15.5Β mm character height, top-viewing
GR10A β Gas-filled digital indicator tube with a dekatron-type readout
GR10G β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 16.86 x 30Β mm characters, side-viewing
GR10H β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 12 x 19Β mm characters, top-viewing
GR10J β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 16.86 x 30Β mm characters, side-viewing
GR10K β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 12 x 19Β mm characters, top-viewing
GR10M β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 10 x 15.5Β mm characters, top-viewing
GR10W β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 8.42 x 15Β mm characters, side-viewing, all-glass wire-ended
GR12G β Β A B C D E F G H I J K LΒ Neon-filled digital indicator tube, 16 x 30Β mm characters, side-viewing
GR12H β Β E L M N P R S T U V W XΒ Neon-filled digital indicator tube, 16 x 30Β mm characters, side-viewing
Note: More Nixie tubes under standard - ZM and professional - ZM
GS10C β 4Β kHz max. Decade Counter/Selector Dekatron, top-viewing, duodecal base
GS10D β Hydrogen-filled, 20Β kHz max. Decade Counter/Selector Dekatron, duodecal base
GS10H β 4Β kHz max. Decade Counter/Selector Dekatron with routing guides, B17A base
GS12C β 4Β kHz max. Duodecimal Counter/Selector Dekatron, with solder lugs
GS12D β Neon-filled, 4Β kHz max. duodecimal Counter/Selector Dekatron, duodecal base with two additional wire-ends for the guide electrodes
GSA10G β 10Β kHz max. Decade Counter/Selector Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base
GTE120Y β 5Β mA Subminiature DC trigger tetrode, one starter and one primer, all-glass wire-ended
GTE130T β 8Β mApeak DC trigger tetrode, one starter and one primer, close tolerance, low aging, quadrant I operation only, noval base
GTE175M β 3.5Β mAavg, 50Β mApeak DC Trigger tetrode, one starter and one primer, miniature 7-pin base, for Dekatron coupling circuits
GTR120W β 9Β mA Subminiature DC trigger triode, 3-pin all-glass wire-ended, for computer applications
GTR75M β 75Β V Voltage reference, Miniature 7-pin
GTR95M/S β 95Β V Voltage reference, Miniature 7-pin
GTR150 β Subminiature, primed 150Β V voltage reference, all-glass wire-ended
VS10G β Trochotron, an electron-beam decade counter tube
VS10G-M β VS10G with a magnetic shield
VS10H β High-current trochotron
VS10K β Low-voltage trochotron
Marconi-Osram system
The British GECβMarconiβOsram designation from the 1920s uses one or two letter(s) followed by two numerals and sometimes by a second letter identifying different versions of a particular type.
The letter(s) generally denote the type or use:
Note: A preceding letter M indicates a 4-volts AC indirectly heated tube
A β General professional tube
B β Dual triode
D β Detector diode
GT β Gas-filled triode
GU β Gas-filled rectifier
H β High-impedance signal triode
KT β Kinkless Tetrode - beam power tube
L β Low-impedance signal triode
N β Power pentode
P β Power triode up to 3 W
PT β Power pentode
PX β 3...25 W Power triode
QP β Dual pentode
S β Tetrode
U β Rectifier
VS β Remote-cutoff tetrode
W β Remote-cutoff pentode
X β Triode/hexode frequency-changer
Y β Optical tuning/level indicator
Z β Sharp-cutoff RF pentode
The following numbers are sequentially assigned for each new device.
Examples:
A1834 = 6AS7G/ECC230 = CV2523 β Dual power triode (series regulator), octal base.
B309 = 12AT7/ECC81 β High-mu dual triode. Commonly used as R.F. amplifier/mixer in VHF circuits.
B719 = 6AQ8/ECC85 β Dual RF triode, RF Amp & Mixer in FM receivers, noval base.
D41 = V914 β Indirectly heated, Dual Detector Diode, British 5-pin base.
D42 β Indirectly heated, Single Detector Diode, British 4-pin base.
GU21 = AH221 = RG4-1250 β Half-wave mercury-vapor rectifier, Edison screw lamp base.
H63 = 6F5 β High-mu triode, octal base.
H610 β Directly heated, high-mu AF triode, British 4-pin base.
KT32 (25L6, 25L6G, 25L6GT and 25W6GT)
KT33 (25A6GT)
KT41
KT61 (6M6G) in parallel filament circuits
KT63 (6F6, 6F6G, 6F6GT)
KT66 (6L6GC)
KT67 β Small transmitting valve
KT71 (50L6GT)
KT77 β Similar to EL34, 6CA7
KT81
KT88 = 6550A = CV5220 (12E13, 7D11) β AF beam power tube, two tubes are capable of providing 100W output, Class-AB1, octal base
L63 = 6J5 β Low-mu triode, octal base.
L610 β Directly heated, Low-mu RF triode, British 4-pin base.
MT7A, MT7B β Large radiation-cooled transmitting triodes used in the 1920s and 1930s.
MU14 = UU5 = IW4-500 β Indirectly heated full-wave rectifier, British 4-pin base.
N77 = 6AM5/EL91 β Power pentode, 7-pin miniature base.
P425 = PM254 β Power triode with a 4Β V/200Β mA battery heater and a British 4-pin base
P610 β Directly heated, AF power triode, British 4-pin base.
P625 β AF power triode.
PX4 β AF power triode designed in the 1930s. Capable of providing about 4.5Β W of audio.
QP21 β Directly heated, dual AF (push-pull) power pentode, British 7-pin base.
QP240 β Directly heated, dual AF (push-pull) power pentode, British 9-pin base.
S610 β Directly heated, Sharp-cutoff RF tetrode, British 4-pin base.
U52 = 5U4G = 5AS4A/5U4GB β Full-wave rectifier, octal base.
VS24 β Directly heated, Remote-cutoff RF tetrode, British 4-pin base.
W727 = 6BA6/EF93 = 5749 β Remote-cutoff RF pentode, 7-pin miniature base.
X41 β Triode/hexode mixer designed to be a direct plug-in replacement for the MX40 pentagrid converter.
X61, X61M = 6J8G β British triode/heptode mixer, octal based.
X63 = 6A8 β Heptode pentagrid converter, octal based.
X727 = 6BE6/EK90 = 5750 β Pentagrid converter, 7-pin miniature base.
Y61, Y63 = 6U5G = VI103 β Optical tuning/level indicator, octal base, similar to 6G5.
Z77 = 6AM6/EF91 β Sharp-cutoff RF pentode, 7-pin miniature base.
Mullard designations before 1934
Older Mullard tubes were mostly designated PM, followed by a number containing the filament voltage.
Many later tubes were designated one to three semi-intuitive letters, followed by a number containing the heater voltage. This was phased out after 1934 when Mullard adopted the MullardβPhilips scheme.
Examples:
2D4 β Dual Diode with a 4Β V/650Β mA heater and a British 5-pin base
AP4 = 4676 β Acorn UHF pentode up to 430Β MHz, 4Β Volts heater
AT4 = 4675 β Acorn UHF triode up to 430Β MHz, 4Β Volts heater
FC4 β Octode Frequency Converter with a 4Β V/650Β mA heater and a British 7-pin base; similar to the M-OV/GEC MX40 heptode
Pen20 β Power Pentode with a 20Β V/180Β mA heater and a British 5- or 7-pin base
PM254 = P425 β "Super Power" triode with a 4Β V/200Β mA battery heater and a British 4-pin base
TDD4 = MHD4 = AC/HLDD β Triode, dual Diode with a 4Β V/550Β mA heater and a British 7-pin base
TH21C β Triode/Hexode frequency converter with a 21Β V/200Β mA series heater and a British 7-pin base
TP4 = AC/TP β Triode, Pentode with a 4Β V/1.25Β A heater and a British 9-pin base
VP2 = VP21 = VP215 β Variable-mu Pentode with a 2Β V/180Β mA heater and a British 7-pin base
Philips system before 1934
The system consisted of one letter followed by 3 or 4 digits. It was phased out after 1934 when Philips adopted the MullardβPhilips scheme.
1st letter: Heater current
A β 60...90Β mA
B β 100...190Β mA (This designation lived on as the "B" (180Β mA) in the MullardβPhilips system)
C β 200...390Β mA (This designation lived on as the "C" (200Β mA) in the MullardβPhilips system)
D β 400...690Β mA
E β 700...1350Β mA
F β 1.25...2Β A
1 or 2 digit(s): Heater voltage
Last 2 digits: Type
00β40, 99: Triode amplification factor
41β98:
second-last digit: sequentially assigned, starting at 4
last digit:
1 β Tetrode with a space charge grid (the 2nd grid is the control grid)
2 β Tetrode with a screen grid (the 1st grid is the control grid)
3 β Power pentode
4 β Binode, a diode/triode or diode/tetrode
5 β Remote-cutoff RF tetrode
6 β Signal pentode
7 β Remote-cutoff RF pentode
8 β Sharp-cutoff hexode frequency changer
9 β Remote-cutoff hexode
Examples:
A106 β Directly heated triode, 1Β V, 60Β mA filament, amplification factor = 6
A425 = RE034 = HR406 β RF triode, 4Β V, 60Β mA filament
A435 β Directly heated triode, 4Β V, 60Β mA filament, amplification factor = 35
A441 β Directly heated tetrode with a space charge grid, 4Β V, 60Β mA filament
A442 = RES094 = S406 β Directly heated tetrode with a screen grid, 4Β V, 60Β mA filament
B409 = RE134 = L414 β Triode, 4Β Volt, 140Β mA filament
B2038 = REN1821 = R2018 = A2118 β Triode, 180Β mA heater
B2043 = RENS1823D = PP2018D = L2318D β Indirectly heated power pentode, 20Β V, 180Β mA DC series heater
B2044 = RENS1854 = DS2218 β Indirectly heated diode/tetrode, 20Β V, 180Β mA DC series heater
B2044S = REN1826 β Indirectly heated diode/triode, 20Β V, 180Β mA DC series heater
B2045 = RENS1819 β Indirectly heated remote-cutoff RF tetrode, 20Β V, 180Β mA DC series heater
B2048 = RENS1824 = MH2018 β Hexode mixer, 20Β V, 180Β mA heater
B2099 = REN1814 β Indirectly heated triode, 20Β V, 180Β mA DC series heater, amplification factor = 99
E443H = RES964 = PP4101 = L496D β Power pentode, 4Β V heater
E446 = RENS1284 = HP4101 β Indirectly heated RF pentode, 4Β V, 1.1Β A heater
E447 = RENS1294 = HP4106 β Indirectly heated remote-cutoff RF pentode, 4Β V, 1.1Β A heater
E448 = RENS1224 = MH4100 β Indirectly heated sharp-cutoff hexode frequency changer, 4Β V, 1.2Β A heater
E449 = RENS1234 = FH4105 β Indirectly heated remote-cutoff hexode, 4Β V, 1.2Β A heater
F215 β Indirectly heated triode, 2.5Β V, 1.5Β A heater, amplification factor = 15
STC/Brimar receiving tubes system
First number: Type
1 β Half-wave rectifier
2 β Diode
3 β Power triode
4 β High-mu triode
5 β Sharp-cutoff tetrode
6 β Vari-mu tetrode
7 β Power or video pentode
8 β Sharp-cutoff RF pentode
9 β Vari-mu RF pentode
10 β Dual diode
11 β Triode and dual diode
12 β AF Pentode and dual diode
13 β Dual high-mu triode
14 β Dual Class-B power triode
15 β Heptode
16 β DC-coupled power triode
17 β RF pentode and dual diode
18 β Pentode and triode
20 β Hexode/heptode and triode
Next letter: Heater rating
A β 4Β V Indirectly heated
B β 2Β V Directly heated
C β Other directly heated
D β Other indirectly heated
Number: Sequentially assigned number
Examples:
1D6 β Indirectly heated, half-wave rectifier, British 5-pin base
4D1 β Indirectly heated triode, British 7-pin base
7A3 β Indirectly heated power pentode, British 7-pin base
8A1 β Indirectly heated RF sharp-cutoff pentode, British 5-pin base with anode top cap
9A1 β Indirectly heated RF/IF remote-cutoff pentode, British 5-pin base with anode top cap
10D1 β Indirectly heated, common-cathode dual diode, British 5-pin base
11A2 β Indirectly heated, common-cathode dual diode and triode, British 7-pin base
13D3 β Indirectly heated, common-cathode dual triode, Noval base
15A2 β Indirectly heated, heptode pentagrid converter, British 7-pin base
20D4 β Indirectly heated, triode/heptode frequency mixer, Noval base
Valvo system before 1934
Valvo(de, it) was a major German electronic components manufacturer from 1924 to 1989; a Philips subsidiary since 1927, Valvo was one of the predecessors of NXP Semiconductors.
The system consisted of one or two letters followed by 3 or 4 digits. It was phased out after 1934 when Valvo adopted the MullardβPhilips scheme.
First letter(s): Type
A β Triode
AN β Binode, a diode/triode or diode/tetrode
G β Rectifier
H β RF tube
L β Power tube
LK β Power amplifier
U β Triode with a space charge grid
W β Triode for resistor-coupled amplifiers
X β Hexode
Number:
If the first digit is 4, the tube has a 4Β V heater
Otherwise, the last two digits give the heater current in tens of mA.
A following letter D indicates more than one grid, not counting a space charge grid
Examples:
A2118 = B2038 = REN1821 = R2018 β Triode, 180Β mA (=18Γ10 mA) heater
H2018D = B2042 = RENS1820 = S2018 β RF Tetrode, 180Β mA heater
L496D = E443H = RES964 = PP4101 β Power pentode, 4Β V heater
L2318D = B2043 = RENS1823D = PP2018D β Power pentode, 180Β mA heater
East European systems
Lamina transmitting tubes system
Polish Lamina(pl) transmitting tube designations consist of one or two letters, a group of digits and an optional letter and/or two digits preceded by a "/" sign.
The first letter indicates the tube type, two equal letters denoting a dual tube:
P β Pentode
Q β Tetrode
T β Triode
A group of digits represents the maximum anode power dissipation in kW
An optional letter specifies the cooling method:
<none> β Radiation
P β Forced air
W β Water
The first of the two digits after the "/" sign means:
1 β Tube for radio broadcasting and radiocommunication equipment
2 β Tube for industrial equipment
3 β Tube used in TV broadcasting equipment
4 β Tube for radiocommunication equipment with unbalanced modulation
5 β Modulator or pulse tube
The second digit after the "/" is sequentially assigned.
Examples:
Q01 β Power tetrode up to 125Β MHz, 0.1Β kW (=100Β W)
Q3.5 β Power tetrode up to 220Β MHz, 3.5Β kW
QQ-004/11 β Dual beam power tetrode up to 500Β MHz, 0.04Β kW (=40Β W)
T01 β Power triode up to 200Β MHz, 135Β W
T015/21 β Power triode up to 150Β MHz, 150Β W
T02 β Power triode up to 60Β MHz, 200Β W
T05P/31 β Forced air cooled power triode up to 1Β GHz, 1Β kW
T2/22 β Power triode up to 60Β MHz, 3Β kW
T6 β Power triode up to 30Β MHz, 6Β kW
T8P/21 β Forced air cooled power triode up to 120Β MHz, 8Β kW
T10P/22 β Power triode up to 30Β MHz, 10Β kW
T-25P β Forced air cooled power triode up to 30Β MHz, 25Β kW
T60W/21 β Water cooled power triode up to 30Β MHz, 6Β kW
RFT transmitting tubes system
Rundfunk- und Fernmelde-Technik(de, sv) was the brand of a group of telecommunications manufacturers in the German Democratic Republic. The designation consists of a group of three letters and a group of three or four digits.
The first two letters determine the tube type:
GR β Rectifier tube
SR β Transmitter tube
VR β Amplifier tube
The third letter specifies the cooling method:
L β Forced air
S β Radiation
V β Vapor (the anode is immersed in evaporating water, and the steam is collected, condensed and recycled)
W β Water
The first digit (or the first two digits in double tubes) indicates the number of electrodes:
2 β Diode
3 β Triode
4 β Tetrode
5 β Pentode
The last two digits are sequentially assigned.
Examples:
SRS301 β Radiation-cooled triode up to 40Β MHz, 900Β W
SRS464 β Radiation-cooled, vibration-resistant pulse tetrode up to 300Β kW
SRS4451 β Radiation-cooled dual tetrode up to 500Β MHz, 60Β W
SRS4452 = QQE03/20 = 6252 β Radiation-cooled dual tetrode up to 600Β MHz, 20Β W
SRS4452 β Radiation-cooled dual tetrode up to 600Β MHz, 20Β W
SRS501 β Radiation-cooled pentode up to 50Β MHz, 100Β W
SRS552N = ΠΠ£-50 β Radiation-cooled pentode up to 120Β MHz, 50Β W
VRS303 β Radiation-cooled AF triode, 1Β kW
VRS328 β Radiation-cooled AF triode, 150Β W
VRS331 β Radiation-cooled AF triode, 450Β W
Note: RFT used the MullardβPhilips and RETMA schemes for their low-power tubes.
Tesla systems (Czechoslovakia)
Signal tubes
Besides the genuine MullardβPhilips system, Tesla also used an M-P/RETMA hybrid scheme:
First number: Heater voltage, as in the RETMA system
Next letter(s): Type, subset of the MullardβPhilips system
Next digit: Base
1 β Octal K8A
2 β Loctal B8G
3 β Miniature 7-pin B7G
4 β Noval B9A
5 β Special, mostly 9 out of 10 1.25mm pins on a 25mm-diameter circle
6 β Submagnal B11A
7 β Duodecal B12A
8 β Diheptal B14A
9 β Wire-ends
Last digit: Sequentially assigned number
Examples:
1M90 (DM70/1M3) β Subminiature indicator tube, 1.4V/25 mA filament, all-glass wire-ended
1Y32 β Miniature 7-pin High-voltage directly heated rectifier with 1.4Β V/265Β mA WTh filament. Type 1Y32T has oxide cathode.
4L20 β Directly heated RF power pentode; center-tapped 4.2Β V/325Β mA filament; Soviet 4P1L (4Π1Π), German RL4,2P6 with Loctal base
6B31 β Dual diode up to 700Β MHz; 6.3V/300mA heater, miniature 7-pin base
6BC32 (6AV6, EBC91) β Dual diode and triode; 6.3V/300mA heater, miniature 7-pin base
6CC31 (6J6, ECC91) β 600Β MHz dual triode; 6.3V/450mA heater, miniature 7-pin base
6CC42 (2C51) β VHF dual triode; 6.3V/350mA heater, noval base
6F24 β Telecom pentode, 6.3V/450mA heater, Loctal base
6F36 (6AH6) β Sharp-cutoff IF/video pentode, 6.3V/450mA heater, miniature 7-pin base
6H31 (6BE6, EK90) β Heptode mixer; 6.3V/300mA heater, miniature 7-pin base
6L36 (6AQ5, EL90) β Power pentode, 6.3V/450mA heater, miniature 7-pin base
6L41 (5763) β Beam tetrode, 6.3V/750mA heater, noval base
35Y31 β Half-wave rectifier, 35V/150mA series heater; UY1N with miniature 7-pin base
Power tubes
First letter:
R β Rectifier or RF tube
U β Gas-filled power rectifier
Z β Modulator tube
Next letter(s): Type, subset of the MullardβPhilips scheme
Next number: Anode dissipation in W (if radiation cooled) or kW (otherwise)
The next letter specifies the cooling method:
<none> β Radiation
V β Vapor
X β Forced air
Y β Water
Examples:
RA0007B β Directly heated saturated-emission ballast diode. Acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits; UAmax 600Β V IAmax 700Β ΞΌA, noval base
RA100A β 40Β kV, 100Β mA Half-wave rectifier with an E40 Goliath Edison screw lamp base and an anode top cap
RC5B β Cup-type UHF power triode up to 5Β W
RD27AS β Radiation-cooled power triode up to 25Β MHz, 27Β W
RD200B β Radiation-cooled power triode up to 60Β MHz, 200Β W
RD300S β Radiation-cooled power triode up to 200Β MHz, 300Β W
RD150YA β Water-cooled power triode up to 3Β MHz, 150Β kW
RE40AK = KT88
RE65A β Radiation-cooled beam tetrode up to 260Β MHz, 65Β W
RE125C β Radiation-cooled beam tetrode up to 235Β MHz, 125Β W
RE400C β Radiation-cooled beam tetrode up to 235Β MHz, 400Β W
RE20XL β Air-cooled beam tetrode up to 220Β MHz, 20Β kW
REE30A β Radiation-cooled dual beam tetrode up to 250Β MHz, 20Β W
RL15A β Radiation-cooled power pentode up to 60Β MHz, 20Β W
RL40A β Radiation-cooled power pentode up to 120Β MHz, 40Β W
RL65A β Radiation-cooled power pentode up to 15Β MHz, 65Β W
UA025A β 10Β kV, 250Β mA Argon-filled, half-wave rectifier with an E27 Edison screw lamp base and an anode screw top cap
UA5A β 11Β kV, 5Β A Half-wave mercury-vapor rectifier with a 2-pin base and an anode screw top cap
ZD1000F β Radiation-cooled power triode up to 60Β MHz, 1Β kW
ZD1XB β Air-cooled AF power triode up to 1.2Β kW
ZD3XH β Air-cooled power triode up to 60Β MHz, 3Β kW
ZD8XA β Air-cooled power triode up to 20Β MHz, 8Β kW
ZD12YA β Air-cooled AF power triode up to 20Β MHz, 12Β kW
ZE025XS β Air-cooled beam tetrode up to 400Β MHz, 250Β W
Tungsram receiving tubes system before 1934
The Tungsram system was composed of a maximum of three letters and three or four digits. It was phased out after 1934 when Tungsram adopted the MullardβPhilips scheme, frequently preceding it with the letter T, as in TAD1 for AD1.
Letter: System type:
Note: A preceding letter A indicates an indirectly heated tube
D β Detector diode
DD β Dual diode
DG β Tetrode with a space charge grid (the 2nd grid is the control grid)
DS β Diode-tetrode
FH β Remote-cutoff hexode pentagrid converter
G β Preamplifier triode
H β Voltage amplifier triode or grid-leak detector
HP β RF pentode
HR β RF triode
L β AF power triode
MH β Hexode pentagrid converter
MO β Octode pentagrid converter
O β Transmitting tube
P β Power triode
PP β Power pentode
PV β Full-wave rectifier
R β High-Mu triode
S β Tetrode
V β Half-wave rectifier
X β US-licensed tube
Number:
First digit (or the first two digits): Heater voltage
Remaining digits: Heater current in tens of mA, but the last digit is sequentially assigned
Examples:
AS4100 β Tetrode, 4Β V, 1Β A (=100Γ10 mA) indirect heater
FH4105 = E449 = RENS1234 β Indirectly heated remote-cutoff hexode, 4Β V, 1.2Β A heater
HP4101 = E446 = RENS1284 β RF pentode, 4Β V, 1Β A filament
HP4106 = E447 = RENS1294 β Indirectly heated remote-cutoff RF pentode, 4Β V, 1.1Β A heater
HR406 = A425 = RE034 β RF triode, 4Β V, 60Β mA (=6Γ10 mA) filament
L414 = B409 = RE134 β Triode, 4Β Volt, 140Β mA (=14Γ10 mA) filament
MH2018 = B2048 = RENS1824 β Hexode mixer, 20Β V, 180Β mA (=18Γ10 mA) heater
MH4100 = E448 = RENS1224 β Indirectly heated sharp-cutoff hexode frequency changer, 4Β V, 1.2Β A heater
PP2018D = B2043 = RENS1823D = L2318D β Indirectly heated power pentode, 20Β V, 180Β mA DC series heater
PP4101 = E443H = RES964 = L496D β Power pentode, 4Β V heater
PV4200 β Full-wave rectifier, 4Β V, 2Β A (=200Γ10 mA) filament
R2018 = B2038 = REN1821 = A2118 β Triode, 180Β mA heater
S406 = A442 = RES094 β Directly heated tetrode with a screen grid, 4Β V, 60Β mA filament
S2018 = B2042 = RENS1820 = H2018D β RF Tetrode, 180Β mA heater
Russian systems
Vacuum tubes produced in the former Soviet Union and in present-day Russia are designated in Cyrillic. Some confusion has been created in transliterating these designations to Latin.
The first system was introduced in 1929. It consisted of one or two letters (designating system type and, optionally, type of cathode), a dash, then a sequentially assigned number with up to 3 digits.
In 1937, the Soviet Union purchased a tube assembly line from RCA (who at the time had difficulties raising funds for their basic operations), including production licenses and initial staff training, and installed it on the Svetlana/Π‘Π²Π΅ΡΠ»Π°Π½Π° plant in St. Petersburg, Russia. US-licensed tubes were produced since then under an adapted RETMA scheme.
Examples:
6Π€5 = 6F5 β High-mu triode
6Π€6 = 6F6 β Power pentode
6Π₯6 = 6H6 β Dual diode
6Π7 = 6J7/EF37 β Sharp-cutoff pentode
6Π6 = 6L6 β Beam tetrode
6Π7 = 6L7 β Pentagrid converter
6Π7 = 6N7 β Dual power triode
GOST standard tubes system
In the 1950s a 5-element system ( "State standard" ΠΠΠ‘Π’/GOST 5461β59, later 13393β76) was adopted in the (then) Soviet Union for designating receiver vacuum tubes.
The first element is a number specifying filament voltage. The second element is a Cyrillic letter specifying the type of device. The third element is a sequentially assigned number that distinguishes between different devices of the same type.
The fourth element denotes the type of envelope. An optional fifth element consists of a dash followed by one or more characters to designate special characteristics of the tube. This usually implies construction differences, not just selection from regular quality production.
Professional tubes system
There is another designation system for professional tubes such as transmitter ones.
The first element designates function. The next elements varies in interpretation. For ignitrons, rectifiers, and thyratrons, there is a digit, then a dash, then the anode current in amperes, a slash, anode voltage in kV. A letter may be attached to designate water cooling (no letter designates a radiation cooled device). For transmitting tubes in this system, the second element starts with a dash, a sequentially assigned number, then an optional letter specifying cooling method. For phototubes and photomultipliers, the second element is a sequential number and then a letter code identifying vacuum or gas fill and the type of cathode.
Japanese systems
Older numbering system 1930sβ40s
A letter: Structure and usage
E β Electron ray tube
K β Kenotron (rectifier)
U β General-purpose tube
Then a letter: Base and outline
N β Wire-ended (Acorn tubes, etc.)
S β Octal K8A
T β Large 7-pin U7B, ST
t β Small 7-pin U7A, ST
V β 4-pin UV4
X β 4-pin UX4, ST
x β Peanut 4-pin
Y β 5-pin UY5, ST
y β Peanut 5-pin
Z β 6-pin U6A, ST
Then a dash, followed by a sequentially assigned number or the designation of the American original
Then an optional dash, followed by a letter: Version
Examples:
EZ-6G5 = 6G5 β Variable-mu "Magic Eye"-type tuning indicator
KX-80-B β Kenotron
UN-954 = 954 β Acorn sharp-cutoff pentode
UN-955 = 955 β Acorn triode
US-6A8 = 6A8 β Pentagrid converter
US-6L7G = 6L7G β Pentagrid converter
UX-26-B β Medium-mu RF triode
UX-167 β Sharp-cutoff RF pentode
UY-47B β Pentode
UZ-58-A β Remote-cutoff RF/IF pentode
JIS C 7001 system
JIS C 7001 was published in 1951 and modified in 1965 and 1970
A number: Heater voltage range, as in the RETMA scheme
1 β 1Β V β€ Uf < 2Β V
2 β 2Β V β€ Uf < 2.5Β V
3 β 2.5Β V β€ Uf < 4Β V
4 β 4Β V β€ Uf < 5Β V
5 β 5Β V β€ Uf < 6Β V
6 β 6Β V β€ Uf < 7Β V
etc.
Then a letter: Base and Outline
A β Special base
B β Other
C β Compactron (Duodecar)
D β Subminiature round base
E β Subminiature flat base
F β European 4-pin, ST
G β Octal base glass tube (GT)
H β Magnoval
K β Ceramic
L β Loctal
M β Miniature 7-pin
N β Nuvistor
Q β Acorn tube
R β Noval or Neonoval
S β Octal
T β Large 7-pin U7B, ST
W β Small 7-pin U7A, ST
X β 4-pin UX4, ST
Y β 5-pin UY5, ST
Z β 6-pin U6A, ST
Then a dash, followed by a letter: Structure and usage
A β Power triode
B β Beam power tube
C β Pentagrid converter
D β Diode
E β Optical tuning/level indicator
G β Gas-filled rectifier
H β High-mu triode (ΞΌ>30)
K β Kenotron (rectifier)
Even number after K: Full-wave rectifier
Odd number after K: Half-wave rectifier
L β Low-mu triode (ΞΌ<30)
P β Power tetrode or pentode
R β Sharp-cutoff tetrode or pentode
S β Tetrode with a space charge grid (the 2nd grid is the control grid)
T β Gas-filled, grid-controlled
V β Variable-mu (remote-cutoff) tetrode and pentode
X β Other
Then a sequentially assigned number
Then an optional letter: Version
Examples:
2N-H12 β Nuvistor
2X-L2A β Low-mu triode
6C-A10 β Power triode
6G-A4 β Power triode
6G-B8 β Beam power tube
6G-E12A β 2-channel "Magic Eye"-type tuning indicator, rectangular target
6H-B26 β Beam power tube
6M-DE1 β Diode and "Magic Eye"-type tuning indicator, miniature 7-pin base
6M-E4 β "Magic Finger"-type tuning indicator, miniature 7-pin base
6M-E5 = 6ME5 β "Magic Eye"-type tuning indicator, miniature 7-pin base
6M-E10 β "Magic Eye"-type tuning indicator, miniature 7-pin base
6N-H10 β Nuvistor
6R-A8 β Power triode
6R-B10 β Beam power tube
6R-B11 β Beam power tube
Military naming systems
British CV and M8000s naming systems
This system prefixes a three- or four-digit number with the letters "CV", meaning "civilian valve" i.e. common to all three armed services. It was introduced during the Second World War to rationalise the previous nomenclatures maintained separately by the War Office/Ministry of Supply, Admiralty and Air Ministry/Ministry of Aircraft Production on behalf of the three armed services (e.g. "ACR~", "AR~", "AT~", etc. for CRTs, receiving and transmitting valves used in army equipments, "NC~", "NR~" and "NT~" similarly for navy equipments and "VCR~", "VR~" and "VT~" etc. for air force equipments), in which three separate designations could in principle apply to the same valve (which often had at least one prototype commercial designation as well). These numbers generally have identical equivalents in both the North American, RETMA, and West European, MullardβPhilips, systems but they bear no resemblance to the assigned "CV" number.
Examples:
CV1988 = 6SN7GT = ECC32 (not a direct equivalent as heater current is different and bulb is larger)
CV2729 = E80F β An SQ version of EF80 but with revised pin-out and a base screen substituted for the RF screen
The "CV4000" numbers identify special-quality valves though SQ valves CV numbered before that rule came in retain their original CV number:
CV4007 = E91AA β SQ version of 6AL5
CV4010 = E95F β SQ version of 6AK5 or EF95
CV4014 = M8083
The "M8" in the part number denotes that it was developed by the military:
M8083 β Sharp-cutoff pentode, miniature 7-pin base (SQ version of EF91 = 6AM6 = Z77)
M8162 = 6060 β High-mu dual triode, for use as RF amplifier/mixer in VHF circuits, Noval base (SQ versions of ECC81 = 12AT7 = B309)
The principle behind the CV numbering scheme was also adopted by the US Joint Army-Navy JAN numbering scheme which was later considerably expanded into the US Federal and then NATO Stock Number system used by all NATO countries. This part-identification system ensures that every particular spare part (not merely thermionic valves) receives a unique stock number across the whole of NATO irrespective of the source, and hence is not held inefficiently as separate stores. In the case of CV valves, the stock number is always of the format 5960-99-000-XXXX where XXXX is the CV number (with a leading 0 if the CV number only has 3 digits).
U.S. naming systems
One system prefixes a three-digit number with the letters "VT", presumably meaning "Vacuum Tube". Other systems prefix the number with the letters "JHS" or "JAN". The numbers following these prefixes can be "special" four-digit numbers, or domestic two- or three-digit numbers or simply the domestic North American "RETMA" numbering system. Like the British military system, these have many direct equivalents in the civilian types.
Confusingly, the British also had two entirely different "VT" nomenclatures, one used by the Royal Air Force (see the preceding section) and the other used by the General Post Office, responsible for post and telecommunications at the time, where it may have stood for "valve, telephone"; none of these schemes corresponded in any way with each other.
Examples:
"VT" numbering systems
North American VT90 = 6H6
British (RAF) VT90 β VHF Transmitting triode
British (GPO) VT90 = ML4 = CV1732 β Power triode
VT104 β RF pentode
VT105 β RF triode
Other numeral-only systems
Various numeral-only systems exist. These tend to be used for devices used in commercial or industrial equipment. The oldest numbering systems date back to the early 1920s, such as a two-digit numbering system, starting with the UV-201A, which was considered as "type 01", and extended almost continuously up into the 1980s. Three- and four-digit numeral-only systems were maintained by R.C.A., but also adopted by many other manufacturers, and typically encompassed rectifiers and radio transmitter output devices. Devices in the low 800s tend to be transmitter output types, those in the higher 800s are not vacuum tubes, but gas-filled rectifiers and thyratrons, and those in the 900s tend to be special-purpose and high-frequency devices. Use was not rigorously systematic: the 807 had variants 1624, 1625, and 807W.
Other letter followed by numerals
There are quite a number of these systems from different geographical realms, such as those used on devices from contemporary Russian and Chinese production. Other compound numbering systems were used to mark higher-reliability types used in industrial or commercial applications. Computers and telecommunication equipment also required tubes of greater quality and reliability than for domestic and consumer equipment.
Some letter prefixes are manufacturer's codes:
C β RCA/Cunningham
CK, QK, RK β Raytheon Company
ECG β Philips/Sylvania
EM β Eitel McCullough
F β Federal Telephone and Radio
GE, GL β General Electric Corp. (not British General Electric Company)
HK β Heintz & Kaufman, Ltd. (San Francisco, California, USA)
HY β CBS/Hytron
ML β Machlett Laboratories, Inc.
NL β National Electronics, Inc.
NU β National Union Electric Corp.
PL β Philips N.V.
RCA β RCA/Radiotron
SV β Svetlana/Π‘Π²Π΅ΡΠ»Π°Π½Π°
SY β Standard Telephones and Cables Ltd./Brimar
TH β Compagnie FranΓ§aise Thomson-Houston
WE β Western Electric Company
WL β Westinghouse Electric Corp.
XD β Central Electronic Manufacturers (Denville, New Jersey, USA)
For examples, see below
Some designations are derived from the behavior of devices considered to be exceptional.
Mazda/EdiSwan sold their first tubes for 4-volts AC mains transformer (as opposed to home storage battery) heating with the prefix AC/ (for examples see below).
The first beam tetrodes manufactured in the UK in the late 1930s by M-OV, carried a "KT" prefix meaning Kinkless Tetrode (for examples see above).
List of American RETMA tubes
Note: Typecode explained above. See also RETMA tube designation
"0 volt" gas-filled cold cathode tubes
First character is numeric zero, not letter O.
Voltage stabilisers and references
Function in a similar way to a Zener diode, at higher voltages. Letter order (A-B-C) indicates increasing voltage ratings on octal-based regulators and decreasing voltage ratings on miniature-based regulators.
0A2 β 150 volt regulator, 7-pin miniature base
0A3 β 75 volt regulator, octal base, aka VR75
0B2 β 105 volt regulator, 7-pin miniature base
0B3 β 90 volt regulator, octal base, aka VR90
0C2 β 75 volt regulator, 7-pin miniature base
0C3 β 105 volt regulator, octal base, aka VR105
0D3 β 150 volt regulator, octal base, aka VR150
Other cold-cathode tubes
0A4G β 25Β mAavg, 100mApeak Gas triode designed for use as a ripple control receiver; with the cathode tied to the midpoint of a series-resonance LC circuit across live mains, it would activate a relay in its anode circuit while fres is present
0Y4 β 40Β β€Β IΒ β€Β 75Β mA Half-wave gas rectifier with a starter anode, 5-pin octal base
0Z4 β 30Β β€Β IΒ β€Β 90Β mA Argon-filled, full-wave gas rectifier, octal base. Widely used in vibrator power supplies in early automobile radio receivers.
1 volt heater/filament tubes
1.25 volt DC filament subminiature tubes
The following tubes were used in post-World War II walkie-talkies and pocket-sized portable radios. All have 1.25 volt DC filaments and directly heated cathodes. Some specify which end of the filament is to be powered by the positive side of the filament power supply (usually a battery). All have glass bodies that measure from wide, and from in overall length.
1C8 β Pentagrid converter, R8
1D3 β Low-mu high-frequency triode, R8
1E8 β Pentagrid converter, R8
1Q6 β Diode, pentode, R8
1S6 β Diode, pentode, R8
1T6 β Diode, pentode, R8
1V5 β Power pentode, R8
1V6 β Triode-pentode converter, FL
1W5 β Sharp-cutoff pentode, R8
1AC5 β Power pentode, FL
1AD4 β Sharp-cutoff pentode, FL
1AD5 β Sharp-cutoff pentode, R8
1AE5 β Heptode mixer, FL
1AG4 β Power pentode, FL
1AG5 β Diode, pentode, FL
1AH4 β RF pentode, FL
1AJ5 β Diode, sharp-cutoff pentode, FL
1AK4 β Sharp-cutoff pentode, FL
1AK5 β Diode, sharp-cutoff pentode, FL
1.4 volt DC filament tubes
1A3 β High frequency diode with indirectly heated cathode. Used as a detector in some portable AM/FM receivers.
1A7GT/DK32 β Pentagrid converter, re-engineered version of types 1A6 and 1D7-G, designed for use in portable AC/DC/Dry-cell battery radios introduced in 1938. Has 1.4Β V/50Β mA filament.
1B7-GT β Re-engineered version of types 1C6 and 1C7-G, designed for use in dry-cell battery radios with shortwave bands. Has 1.4Β V/100Β mA filament
1G6-G β Dual power triode. "GT" version also available.
1L6 β Pentagrid frequency changer for battery radios with 50Β mA filament
1LA6 (Loctal) and later 1L6 (7-pin miniature) β Battery pentagrid converter for Zenith Trans-Oceanic shortwave radio, 50Β mA filament
1LB6 β Superheterodyne mixer for battery-operated radios
1LC6 β Similar to type 1LA6, but with higher conversion transconductance
1R5/DK91 β Pentagrid converter, anode voltage in the 45...90 volt range.
1S4 β Power output pentode Class-A amplifier, anode voltage in the 45...90 volt range.
1S5 β Sharp-cutoff pentode Class-A amplifier, and diode, used as detector and first A.F. stage in battery radio receivers. Anode voltage in the 67...90 volt range.
1T4/DF91 β Remote-cutoff R.F. Pentode Class-A amplifier, Miniature 7-pin base, used as R.F. and I.F. amplifier in battery radio receivers.
1U4 β Sharp-cutoff R.F. Pentode Class-A amplifier, Miniature 7-pin base, used as R.F. and I.F. amplifier in battery radio receivers, similar characteristics to 6BA6.
1U6 β Nearly identical to type 1L6, but with a 1.4Β V/25Β mA filament
"1" prefix for home receivers
These tubes were made for home storage battery receivers manufactured during the early to mid-1930s; all have 2.0 volt DC filaments despite theΒ 1-prefix, intended to distinguish them from the 2.5 volt AC heated tubes listed below
1A4-p β Remote-cutoff pentode
1A4-t β Remote-cutoff tetrode
1A6 β Pentagrid converter up to only 10Β MHz due to low heater power (2Β V/60Β mA) and consequent low emission in the oscillator section; also occasionally used as a grid-leak detector
1B4-p β Sharp-cutoff pentode
1B4-t β Sharp-cutoff tetrode
1B5 β Dual detector diode, medium-mu triode. Usually numbered 1B5/25S
1C5 β Power pentode (similar to 3Q5 except for filament)
1C6 β Pentagrid converter; 1A6, with double the heater power and double the frequency range
1C7-G β Octal version of type 1C6.
1D5-Gp β Octal version of type 1A4-p.
1D5-Gt β Octal version of type 1A4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
1D7-G β Octal version of type 1A6.
1E5-Gp β Octal version of type 1B4-p.
1E5-Gt β Octal version of type 1B4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
1E7-G β Dual power pentode for use as a driver when parallel-connected, or as a push-pull output. "GT" version also available
1F4 β Power pentode
1F5-G β Octal version of 1F4.
1F6 β Duplex diode, sharp-cutoff pentode
1F7-G β Octal version of type 1F6
1G4-GT/G β Octal triode, mu 8.8
1G5-G β Power pentode
1H4-G β Medium-mu triode, can be used as a power triode. Octal version of type 30, which is an upgraded version of type 01-A. "GT" version also available.
1H6-G β Octal version of type 1B5/25S. "GT" version also available.
1J5-G (950) β AF Power pentode
1J6-G β Dual power triode, octal version of type 19. "GT" version also available.
CRT anode rectifiers
1G3GT β Octal High-voltage rectifier. Same Characteristics as 1B3GT. Many listed and labeled as 1B3GT/1G3GT.
1H2 β Noval High-voltage rectifier with 1.4Β V/550Β mA filament
1J3GT β Octal High-voltage rectifier. Same Characteristics as 1B3GT. Has filament-plate shorting protection. Many listed and labeled as 1J3GT/1K3GT.
1K3GT β Octal High-voltage rectifier. Same Characteristics as 1B3GT. Has filament-plate shorting protection. Many listed and labeled as 1J3GT/1K3GT.
1S2A β Noval High-voltage rectifier with 1.4Β V/550Β mA filament. Similar to DY86, DY87, DY802, 1R10, and 1R12.
1T2 = R16 β Subminiature High-voltage rectifier with 1.4Β V/140Β mA filament. Has flexible leads.
1V2 β High-voltage rectifier with 0.625Β V/300Β mA filament, Miniature 7-pin base
1X2 β Noval High-voltage rectifier with 1.25Β V/200Β mA filament. 1X2A, 1X2B and 1X2C have X-Radiation Shielding. Similar to DY80 and R19.
1Y2 β 4 pin High-voltage rectifier with 1.5Β V/290Β mA filament. 50KV max PIV, 10mA peak, 2mA average. Usable up to 1Β MHz.
1Z1 β Octal High-voltage rectifier with 0.7Β V/180Β mA filament.
1Z2 β Noval High-voltage rectifier with 1.25Β V/265Β mA filament.
1AD2 β Compactron High-voltage rectifier with 1.25Β V/200Β mA filament. Type 1AD2A has X-Radiation Shielding.
1AJ2 β Compactron High-voltage rectifier with 1.25Β V/200Β mA filament
1AY2 β 2-pin "Duopin" base High-voltage rectifier. Has similar electrical characteristics as 1B3GT.
1B3GT β Octal High-voltage rectifier diode with 1.25Β V filament common in monochrome TV receivers of the 1950s and early 1960s. Peak inverse voltage of 30Β kV. Anode current 2Β mA average, 17Β mA peak. Derived from the earlier industrial type 8016. Many listed and labeled as 1B3GT/1G3GT.
1BC2 β Noval High-voltage rectifier with 1.25Β V/200Β mA filament. Types 1BC2A and 1BC2B have X-Radiation Shielding.
1BG2 β Subminiature High-voltage rectifier with 1.4Β V/575Β mA filament. Has flexible leads.
1BQ2 β Noval High-voltage rectifier with 1.4Β V/600Β mA filament
1BY2 β Compactron High-voltage rectifier with 1.25Β V/200Β mA filament. Type 1BY2A has X-Radiation Shielding.
2 volt heater/filament tubes
2.5 volt AC heater tubes
Tubes used in AC-powered radio receivers of the early 1930s
2A3 β Directly heated power triode, used for AF output stages in 1930sβ1940s audio amplifiers and radios.
2A5 β Power Pentode (Except for heater, electronically identical to types 42 and 6F6)
2A6 β Dual diode, high-mu triode (Except for heater, electronically identical to type 75)
2A7 β Dual-tetrode-style pentagrid converter (Except for heater, electronically identical to types 6A7, 6A8 and 12A8)
2B7 β Dual diode and remote-cutoff pentode (Except for heater, electronically identical to type 6B7)
2E5 and 2G5 β Electron-ray indicators ("Eye tube") with integrated control triode. (Except for heater, electronically identical to types 6E5 and 6G5)
CRT anode rectifiers
2X2 β High Vacuum High Peak inverse voltage diode, used as rectifier in CRT EHT supplies. Similar to 1B3 and 1S2 except for heater voltage.
3 volt heater/filament tubes
3A3/3B2/3AW3 - High Voltage rectifier. An octal type used in color television sets. The heater power is 3.15 volts and 0.22 amps.
3CA3 - High Voltage rectifier. An octal type used in color television sets. The heater power is 3.6 volts and 0.225 amps.
3CN3 - High Voltage rectifier. An octal type used in color television sets. The heater power is 3.15 volts and 0.48 amps. The large current is for the advantage of fast warm-up.
3CU3 - High Voltage rectifier. An octal type used in color television sets. The heater power is 3.15 volts and 0.28 amps.
3CZ3 - High Voltage rectifier. An octal type used in color television sets. The heater power is 3.15 volts and 0.48 amps. The large current is for the advantage of fast warm-up.
3AT2 - High Voltage rectifier. A compactron used in television sets to supply power to the anode of the picture tube. It comes in the variation as the 3AT2B, mainly for color television sets with a large picture tube. The 3AT2B comes with X-radiation shielding on the inside. The heater power is 3.15 volts and 0.22 amps.
3AW2 - High Voltage rectifier. A compactron used for color and black and white television sets. It comes in the variation as the 3AW2A as a replacement for the 3AW2 after the 1967 General Electric X-radiation scandal. The 3AW2A comes with X-radiation shielding on the inside. The heater power is 3.15 volts and 0.22 amps.
3BF2 - High Voltage rectifier. A compactron used in television sets to supply power to the anode of the picture tube. This tube is very rare, and very special, because it implements an indirectly heated cathode, not connected to the filament. No data is found on this tube, except for the filament power (which is 3.6 volts, 0.225 amps) and the base (which is the 12GQ type). The only reason why we know it is a high voltage rectifier is that the base tells us so.
3BL2 - High Voltage rectifier. A compactron used in television sets to supply power to the anode of the picture tube. It comes in the variation as the 3BL2A as a replacement for the 3BL2 after the 1967 General Electric X-radiation scandal. The 3BL2A comes with X-radiation shielding on the inside. The heater power is 3.3 volts and 0.285 amps.
3BM2 - High Voltage rectifier. A compactron used in television sets to supply power to the anode of the picture tube. It comes in the variation as the 3BM2A as a replacement for the 3BM2 after the 1967 General Electric X-radiation scandal. The 3BM2A comes with X-radiation shielding on the inside. The heater power is 3 volts and 0.3 amps.
3BN2 - High Voltage rectifier. A compactron used for color television sets. It comes in the variation as the 3BN2A as a replacement for the 3BN2 after the 1967 General Electric X-radiation scandal. The 3BN2A comes with X-radiation shielding on the inside. The heater power is 3.15 volts and 0.22 amps.
3BS2 - High Voltage rectifier. A compactron used for color television sets. It comes in the variation as the 3BS2A and 3BS2B as a replacement for the 3BN2 after the 1967 General Electric X-radiation scandal. The 3BS2A and 3BS2B tubes are identical, maybe a small difference in ratings and characteristics. We do not know these differences as the 3BS2B tube data is not available. The 3BS2A and 3BS2B comes with X-radiation shielding on the inside. The heater power is 3.15 volts and 0.48 amps. The large current is for the advantage of fast warm-up.
3BT2 - High Voltage rectifier. A compactron used for color television sets. It comes in the variation as the 3BT2A as a replacement for the 3BT2 after the 1967 General Electric X-radiation scandal. The 3BT2A comes with X-radiation shielding on the inside. The heater power is 3.15 volts and 0.48 amps. The large current is for the advantage of fast warm-up.
3BW2 - High Voltage rectifier. A compactron used for color and black and white television sets. The 3BW2 comes with X-radiation shielding on the inside. It also comes with diffusion bonded cathode (a type of cathode that prevents the back-emission of the anode). This tube was designed in December 1970, after the 1967 General Electric X-radiation scandal. All high voltage rectifier tube types that were designed before 1967 had no X-radiation protection internally. That is why all these tubes made during and after 1967 have a suffix showing they had internal X-radiation protection. This is why there is no '3BW2A' type since it was made after 1967. The heater power is 3.15 volts and 0.22 amps.
5 volt heater/filament tubes
5R4 β Full wave rectifier
5U4 β Full wave rectifier
5V4, GZ32 β Full wave rectifier
5Y3 β Full-wave rectifier, octal base version of type 80
5AR4, GZ34 β Full wave rectifier
5AS4 β Full wave rectifier
6 volt heater tubes
6A6 β Dual Power Triode, used as a Class-A audio driver or a Class-B audio output. U7B base. 6.3 volt heater version of type 53 which had a 2.5 volt heater. Octal version β 6N7.
6A7 and 6A8 (PH4, X63) β Pentagrid converter β dual tetrode style. Based on type 2A7, which had a 2.5 volt heater. 6A7 has a UX7 base with top cap connection for control grid (grid 4). 6A8 is octal version with top cap connection for control grid. Loctal version: type 7B8.
6B6-G β Dual Diode, High-mu Triode. Octal version of type 75. Has top-cap connection for triode grid. Later octal version, type 6SQ7, has under-chassis connection for triode grid. Miniature version: 6AV6.
6B7 (UX7 base), 6B8 (EBF32, Octal base) β Dual Diode, Semiremote-cutoff Pentodes with control grid on top cap. Based on type 2B7 which had a 2.5 volt heater. The diode anodes are most commonly used as (second) detectors and AVC rectification in superheterodyne receivers. Because their control grids have both sharp-cutoff and remote-cutoff characteristics, these types were used as I.F. amplifiers with AVC bias to the control grid, and as A.F. amplifiers. These types were also used in reflex radios. In a typical 2B7/6B7/6B8 reflex circuit, the I.F. signal from the converter is injected into the pentode and is amplified. The diodes then act as detectors, separating the A.F. signal from the R.F. signal. The A.F. signal is then re-injected into the pentode, amplified, and sent to the audio output tube.
6C4/EC90 β 3.6Β W small-power V.H.F. triode up to 150Β MHz; single 12AU7/ECC82 system
6C6 β Sharp-cutoff R.F. Pentode. Most common commercial uses were as a tuned R.F. amplifier, a detector, and an A.F. amplifier. Also used in test equipment. Has UX6 base with top cap. Based on type 57, which had a 2.5 volt heater. Similar to types 1603, 77 and octal types 6J7 and 6SJ7
6C10 β Compactron High-mu triple triode, 12-pin base β not related to the Mazda/EdiSwan 6C10 triode-hexode
6D4 β 25Β mAavg, 100Β mApeak Indirectly heated, argon triode thyratron, negative starter voltage, miniature 7-pin base; found an additional use as a 0 to 10Β MHz noise source, when operated as a diode (starter tied to cathode) in a transverse 375Β G magnetic field. Sufficiently filtered for "flatness" ("white noise") in a band of interest, such noise was used for testing radio receivers, servo systems and occasionally in analog computing as a random value source.
6D6 β Remote-Cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Has UX6 base with top cap. Based on type 58, which had a 2.5 volt heater. Similar to type 78. Octal version: 6U7-G.
6D8-G β Pentagrid converter, similar to type 6A8. Octal base with top cap. Has 150Β mA heater. Used in pre-war 6-volt farm radios.
6D10 β High-mu triple triode for use as oscillator, mixer, amplifier or AFC tube, 12-pin base
6E5 β "Magic Eye" Tuning indicator. Has incorporated driver triode with sharp-cutoff grid which makes it extremely sensitive to any changes in signal strength. Has UX6 base. Based on type 2E5, which had a 2.5 volt heater.
6F4 β Acorn UHF triode up to 1.2Β GHz, for use as an oscillator
6F5 β High-mu triode, equal to triode section of type 6Q7
6F6 (KT63) β Power Pentode. Octal base version of type 42. Moderate power output rating β 9 watts max. (Single-ended Class-A circuit); 11 watts max. (Push-pull Class-A circuit); 19 watts max. (push-pull Class-AB2 circuit). Available in metal (numbered "6F6"), shouldered glass ("6F6-G"), and cylindrical glass ("6F6-GT"). Sometimes used as a transformer-coupled audio driver for types 6L6-GC and 807 when those tubes were used in Class-AB2 or Class-B amplifiers. Also used as a Class-C oscillator/amplifier in transmitters.
6F7 β Remote-cutoff Pentode, Medium-mu Triode. Has UX7 base with top-cap connection for the pentode's control grid (grid 1). Most common uses were as superheterodyne mixer ("first detector") and local oscillator, or as a combination I.F. amplifier (pentode) and (second) detector or A.F. amplifier (triode). Octal version: 6P7-G.
6G5 β "Magic Eye" Tuning indicator. Has incorporated triode with remote-cutoff grid, which makes it less reactive to low-level changes in signal strength. Has UX6 base. Electronically identical to type 6U5 except for indicator. Both types had "pie wedge" shadow indicators. At first, the shadow indicator for type 6G5 was fully closed at zero signal and opened as signal strength increased. For type 6U5, the shadow indicator was fully open at zero signal and closed as signal strength increased. After World War II, type 6G5 was discontinued as a unique tube and all 6U5s were double-branded either as 6G5/6U5 or 6U5/6G5.
6G6-G β Power pentode. Octal base. Low power output β 1.1 watt max. output. Has 150Β mA heater. Used in pre-war 6-volt farm radios. Miniature version β 6AK6.
6G8-G β Dual Diode, Sharp-cutoff Pentode (Used as Detector and first A.F. stage in Australian 1940s radios)
6H6, D63, EB34, OSW3109 β Dual diode. Octal base. Most commonly found as a "stubby" metal envelope tube. Glass versions 6H6-G and 6H6-GT are also found.
6J5 (Metal), 6J5GT (Glass Tubular), L63 β Heater cathode type, medium-mu triode, identical to 12J5 except heater characteristics
6J5WGT β Premium version of 6J5GT, identical to 12J5WGT except heater characteristics
6J6 β Dual general purpose VHF triode with common cathodes, operates over much of the UHF band (up to 600Β MHz), equivalent to ECC91
6J7, EF37 β Sharp-cutoff Pentode. Most common commercial uses were as a tuned R.F. amplifier, a (second) detector, or an A.F. amplifier. Octal version of type 77. This type included a top-cap connection for the control grid. Later version, type 6SJ7, had its control grid connection on pin 4.
6J8-G β Triode-Heptode (radio local oscillator/mixer)
6K6-G β Power Pentode, octal version of type 41. Low-to-moderate power output rating β 0.35 to 4.5 watts (single-ended Class-A circuit); 10.5 watts max. (push-pull Class-A circuit).
6K7, EF39 β Remote-cutoff R.F. pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 78. This type included a top-cap connection for the control grid. Later version, type 6SK7, had its control grid connection on pin 4.
6K8 and 12K8 β American Triode-Hexode mixer, 1938
6K11 β Compactron 2x High-mu + 1x medium-mu triple triode, 12-pin base
6L4 β Acorn UHF triode for use as an oscillator
6L5-G β Medium-mu triode (Similar to type 6J5-G, available only in ST shape)
6L6 (EL37) β High-powered beam tetrode.
There are several variations. Except for types 6L6-GC and 6L6-GX, all have the same maximum output ratings:
11.5 watts (single-ended Class-A circuit)
14.5 watts (push-pull Class-A circuit)
34 watts (push-pull Class-AB1 circuit)
60 watts (push-pull Class-AB2 circuit)
6L6 (metal envelope) and 6L6-G (shouldered glass envelope) were used in pre-World War II radios and Public Address amplifiers.
6L6 and 25L6 were introduced in 1935 as the first beam tetrodes. Both types were branded with the L6 ending to signify their (then) uniqueness among audio output tubes. However, this is the only similarity between the two tubes. (Type 6W6-GT is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.)
6L6GA β Post-war version of type 6L6-G, in smaller ST-14 shape with Shouldered Tubular, (ST), shaped bulb, revision A.
6L6GB β Post-war improved version in a cylindrical glass envelope. Similar to type 5881.
6L6GTB β 6L6 with Tubular, (T), shaped bulb, revision B, (higher power rating, as it happens. The 6L6GTB can always replace the 6L6, 6L6G, and 6L6GT, but a 6L6GTB running at maximum rating should not be replaced with another subtype).
6L6-WGB β "Industrial" version of type 6L6GB.
6L6GC β Final and highest-powered audio version of the tube. Max. outputs:
17.5 watts (single-ended Class-A circuit)
32 watts (push-pull Class-A circuit)
55 watts (push-pull Class-AB1 circuit)
60 watts (push-pull Class-AB2 circuit)
6L6-GX β Class-C oscillator/amplifier used in transmitters. Max. output 30 watts. (All versions may be used as a Class-C oscillator/amplifier, but this version is specifically designed for this purpose, has a special ceramic base.)
6L7 β Pentagrid converter often used in console radios of the late 1930s. Similar in structure to pentode-triode pentagrid converters 6SA7 and 6BE6, except that a separate oscillator β usually type 6C5 β is required. Also, grid 1 is remote-cutoff control grid, grid 3 is oscillator input grid. (In types 6SA7 and 6BE6, grid 1 is the internal oscillator grid, grid 3 is the control grid.) Because of low conversion transconductance, radios using type 6L7 typically have either a tuned RF pre-amplifier stage, or at least two stages of I.F. amplification. (A few models have both.)
6M5 β Audio Output Pentode (Used as Class-A or C output stages of 1950s Australian radiograms) similar to 6BQ5
6M11 β Compactron Dual triode and pentode
6N3, EY82 β Half-Wave Rectifier
6N5 β Tuning indicator
6N7 β Dual Power Triode, used as Class-A audio driver or as Class-B power output (also 6N7-G and 6N7-GT). Max. output (Class-B) β 10 watts. Octal version of type 6A6.
6N8, EBF80 β Remote-cutoff pentode, dual diode. (detector plus RF or AF amplifier in radios)
6P5-G/GT β Medium-mu triode, Octal version of type 76, often used as driver for type 6AC5-G.
6P7-G β Rarely seen octal version of type 6F7.
6Q5-G β Triode gas thyratron used in DuMont oscilloscopes as a sweep generator. Identical to type 884.
6Q11 β Medium-mu triple triode, 12-pin base, for use as a sync clipper and gated AGC amplifier in TV receivers
6R3, EY81 β TV "Damper/Efficiency" Diode
6R7 β Dual Diode, Medium-mu Triode (also 6R7-G and 6R7-GT). Octal base with top cap. Miniature version β 6BF6. Amplification factor: 16.
6S7-G β Remote-cutoff RF Pentode, similar to type 6K7. Octal base with top cap. Has 150Β mA heater. Used in pre-war 6-volt farm radios.
6S8-GT β Triple Diode, High-mu Triode. Octal tube with top-cap connection to triode grid. Has three identical diodes β two diodes share a cathode with the triode, one has a separate cathode. Used as a combined AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in AM/FM radios. Typically, all sections of this tube are arranged around a single heater.
6T5 β "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has UX6 base. Shadow indicator is fully closed at zero signal. As signal increases, shadow grows outward from the center, covering the entire circumference of the indicator. Electronically identical to types 6G5 and 6U5, which may be used as substitutes.
6T7-G β Dual diode, high-mu triode, similar to type 6Q7. Octal base with top cap. Has 150Β mA heater. Used in pre-war farm radios.
β Triple Diode, High-mu Triode. Has three identical diodes β two have cathodes connected to the triode's cathode, one has a separate cathode. Triode amplification factor: 70. Used as an AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in North American AM/FM radios. Identical to type 6AK8/EABC80, but with a shorter glass envelope.
6U5 (UX6 base), 6U5G (Octal base) β "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has "pie wedge" shadow indicator that is open at zero signal and closes as signal increases. Electronically identical to types 6G5 and 6T5 and may be used as a substitute for those types. After World War II, most new 6U5s were double-branded as either 6G5/6U5 or 6U5/6G5.
6U7-G β Remote-cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 6D6. Most direct substitute: 6K7. Similar to types 58, 78 and 6SK7.
6U8A β Triode-pentode, Noval base. Audio preamplifier.
6U10 β 1x High-mu + 2x medium-mu triple triode, 12-pin base
6V4 (EZ80) β Noval-base, indirectly heated, full-wave rectifier. EZ80 rated at 90mA, but 6V4 only rated for 70. Some brands were identical.
6V6 β Beam power tetrode, used in single-ended Class-A audio output stages of radios and sometimes seen in Class-B audio amplifiers (see also: 5V6 and 12V6). Electrically similar to 6AQ5/EL90.
6V6G β 6V6 with Shouldered Tubular, (ST), shaped bulb.
6V6GT β 6V6 with Tubular, (T), shaped bulb.
6V7-G β Dual diode, Medium-mu Triode. Octal version of type 85. Amplification factor: 8.3. Similar to type 6R7.
6W6-GT β Beam power pentode, used most often as a Vertical Deflection Output tube in monochrome TV receivers of the 1950s. Can also be used as an Audio Output tube. This is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.
6X4 (EZ90) and 6X5 (EZ35) β Full-wave rectifiers with indirectly heated common cathode. Type 6X4 has a 7-pin miniature base, the 6X5 has an octal base. Based on type 84/6Z4. No longer in production.
6AB4/EC92 β High-mu triode (Pinout same as 6C4 except for pin 5 not having a connection)
6AB5/6N5 β "Magic Eye" cathode ray tuning indicator
6AC5-G β High-mu Power Triode
6AC7, 1852 β TV sharp-cutoff R.F. Pentode. (Often encountered in a black metal envelope, not to be confused with the 6CA7.)
6AC10 β Compactron High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
6AD6-G and 6AF6-G β "Magic Eye" tuning indicators. Both have two "pie wedge" shadow indicators, one each on opposite sides of a single circular indicator target. Both shadows may be used in tandem or may be driven by two different signal sources. Type 6AE6-G is specifically made to drive each indicator with different signals. May also be driven by separate pentodes with different characteristics. E.g., a sharp-cutoff pentode like a 6J7 β which would be hyper-sensitive to any signal change β would drive one shadow, while a remote-cutoff pentode like a 6K7 β which would only react to stronger signals β would drive the other shadow. Both tubes have octal bases. Type 6AD6-G, with a target voltage rated from 100 to 150 volt, is designed for AC/DC radios. Type 6AF6-G, with a target voltage rated at 250 volt, is designed for larger AC radios.
6AE6-G β A driver triode specially designed for "Magic Eye" tuning indicator types 6AD6-G and 6AF6-G. Has a common heater and indirectly heated cathode, two internally connected triode grids β one with sharp-cutoff characteristics, one with remote-cutoff characteristics β and two anodes, one for each grid. The sharp-cutoff grid reacts to any signal change, while the remote-cutoff grid reacts only to stronger signal changes.
6AE7-GT β Dual Triode with a common, single anode, for use as a power triode driver
6AF4 β UHF Medium-mu Triode, commonly found in TV UHF tuners and converters.
6AF11 β Compactron High-mu dual triode and sharp-cutoff pentode
6AG11 β Compactron High-mu dual triode and dual diode
6AH5-G β Beam power tube for early TV use. Same as type 6L6-G, but with scrambled pinout. Used in some Philco receivers.
6AK5, EF95, 5654, CV4010, 6J1P (6Π1Π) β Miniature V.H.F. Sharp-cutoff pentode (Used in old Radiosonde weather balloon transmitters, receiver front ends and contemporary audio equipment), Miniature 7-pin base
6AK6 β Power pentode. 7-pin miniature version of type 6G6-G. Unusual low-power consumption output tube with 150Β mA heater.
/EABC80 β Triple Diode, High-mu Triode. Diodes have identical characteristics β two have cathodes connected to the triode's cathode, one has a separate cathode. Used as a combination AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in AM/FM radios manufactured outside of North America. Triode amplification factor: 70. North American type 6T8 is identical (but for a shorter glass envelope) and may be used as a substitute.
6AK9 β Compactron 1x high-mu + 1x medium-mu dual triode and beam power pentode, 12-pin base
6AK10 β Compactron High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
6AL3, EY88 β TV "Damper/Efficiency" Diode
6AL5, EAA91, D77 β Dual Diode, Detector. Often used in vacuum tube volt meters (VTVMs). Miniature version of type 6H6.
6AL6-G β Beam power tube for early TV use. Same as type 6L6-G, but with scrambled pinout and anode connected to top cap.
6AL7-GT β Tuning indicator used in many early AM/FM Hi-Fi radios. Similar in function to "Magic Eye" tubes. Has two bar-shaped shadows; one grows to indicate signal strength, the other moves to indicate center tuning on FM.
6AM6, EF91, Z77 β Sharp-cutoff R.F. pentode used in receiver front ends and test gear such as VTVMs and TV broadcast modulation monitors.
6AN7, β Triode-Hexode Oscillator/Mixer (radio)
6AN8, β Triode-Pentode used in frame timebase circuits for television. Electrically fairly similar to ECL80 but with a different pinout.
6AQ5 β Beam-power pentode, 7-pin miniature similar of type 6V6.
6AQ8/ECC85 β Dual triode with internal shield. Designed for use as oscillator and mixer in FM receivers. The heater to cathode insulation is inadequate for use in cascode operation
6AR8, 6JH8, 6ME8 β Beam deflection tubes for use as NTSC chroma signal demodulators in analog color TV receivers
6AS6 β Pentode with a fine-pitched suppressor grid which could serve as a second control grid. Used in radar phantastron circuits.
6AS7, 6080 β Dual low-mu Triode, low impedance, mostly used for voltage regulation circuits.
6AS11 β Compactron 1x high-mu + 1x medium-mu dual triode and sharp-cutoff pentode, 12-pin base
6AT6 β Dual Diode, High-mu Triode, miniature version of type 6Q7. Triode amplification factor: 70.
6AU4 β TV "Damper/Efficiency" Diode
6AU6, EF94, 6AU6A β Sharp-cutoff pentode
6AV6 β Dual Diode, High-mu Triode, miniature version of type 75. Triode amplification factor: 100. (Triode section similar in characteristics to one half of a 12AX7.)
6AV11 β Compactron Medium-mu triple triode, 12-pin base
6AX4 β TV "Damper/Efficiency" Diode
6AX5 β Full-wave rectifier. Octal base. Similar in structure to type 6X5, but with higher voltage and current ratings which are comparable to those of types 5Y3 and 80.
6BA6, EF93, W727, 5790 β Semiremote-cutoff R.F. Pentode (Often encountered in car radios)
6BD11 β Compactron 1x high-mu + 1x medium-mu dual triode and sharp-cutoff pentode, 12-pin base
6BE6, EK90, 5750, X727 β Pentagrid Converter (Often encountered in car radios)
6BF6 β Dual Diode, Medium-mu triode. Miniature version of octal type 6R7.
6BF8 β Sextuple diode with a common cathode
6BG6 β Beam tetrode, anode cap. Used in early TV magnetic-deflection horizontal-output stage.
6BH11 β Compactron Medium-mu dual triode and sharp-cutoff pentode
6BK4 β High Voltage beam Triode (30Β kV anode voltage). Used as shunt regulator in color TV receivers and measurement equipment such as high voltage meters
6BK7 β Dual Triode with Internal shield between each section, used in RF circuits (Similar to 6BQ7)
6BK8, EF86, Z729 β Audio Pentode used in microphone preamplifiers and audiophile equipment
6BK11 β Compactron 2x High-mu + 1x medium-mu triple triode preamplifier, 12-pin base; used in some guitar amps made by Ampeg.
6BL6 (5836) β Sutton tube, a reflex klystron used as a 250Β mW CW microwave source, 1.6 to 6.5Β GHz depending upon an external cavity. 4-pin peewee base with cavity contact rings and top cap
6BL8, ECF80 β General-purpose Triode pentode used in TV, audio and test gear
6BM6 (5837) β Sutton tube used as a 150Β mW CW microwave source, 550Β MHz to 3.8Β GHz depending upon an external cavity. 4-pin peewee base with cavity contact rings and top cap
6BM8, ECL82 β Triode pentode used as the driver and output stages in audio amplifiers, audio output and vertical output stages in TV receivers and has even been seen in an electronic nerve stimulator.
6BN6 β Gated-beam discriminator pentode, used in radar, dual channel oscilloscopes and F.M. quadrature detectors (cf. 6DT6, nonode).
6BQ5, EL84,(N709) β 5.7Β Watts AF Power pentode, noval base
6BQ6-GT β Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV receivers of the 1950s. Most commonly used in receivers with diagonal screen sizes less than . (However, may be found in some larger models.) Larger receivers often used similar type 6DQ6. Later versions of this tube branded as 6BQ6-GTB/6CU6.
6BQ7 β Dual RF/VHF triode with internal screen. The two sections can be used independently or in a cascode stage
6BQ7A β Improved 6BQ7 capable of operation at UHF frequencies
6BU8 β Split Anode TV Sync Separator
6BX6, EF80 β Sharp-cutoff RF/IF/Video pentode, noval base
6BY6 β Similar to type 6CS6, but with higher transconductance. 3BY6 with a different heater
6BY7, EF85, W719 β Remote-cutoff R.F. Pentode (TV IF)
6BZ6 β Sharp-cutoff R.F. pentode used in video I.F. circuits of the 1960s.
6BZ7 β Dual Triode. See 6BK7
6CA4, EZ81 β Full Wave Rectifier
6CA7, EL34 β Audio Power Output Pentode
6CA11 β Compactron High-mu dual triode and sharp-cutoff pentode
6CB6 β Remote-cutoff R.F. Pentode used in video I.F. circuits of the 1950s and early 1960s.
6CG7 β Dual Triode (used in TV and some audio amplifiers including modern solid-state designs often as a cathode follower, similar to 6SN7)
6CJ6 β Line Output Pentode
6CL6 β Power pentode
6CM5, EL36, EL360 β Audio and TV Line Output Beam Power Tetrode.
6CS7 β Double Triode with dissimilar triodes. Used in televisions and tube amplifiers. 6CS7 Tube, Double Triode, Data Sheets | Bergholt.net
6CW4 β Nuvistor high-mu VHF triode, most common one in consumer electronics
6CZ5 β Beam pentode for use in vertical deflection or audio amplifier. In certain applications, it can be used in place of a 6973.
6DA6, EF89 β R.F. Pentode used in AM/FM radios manufactured outside North America.
6DJ8, ECC88, E88CC, 6922, 6N23P, 6N11 β Dual Audio and R.F. Triode (often used in TV broadcast equipment, test gear, oscilloscopes and audiophile gear) similar to 6ES8
6DQ6 β Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV receivers of the 1950s. Most often found in receivers with diagonal screen measurements larger than . Smaller receivers often used similar type 6BQ6-GT. Also used as Audio Output tubes in Standel guitar amplifiers. Later versions branded as 6DQ6-B/6GW6.
6DR8, EBF83 β R.F. pentode which will operate with 12Β V anode supply, used as I.F. amplifier in car radios which run directly off the 13.5 volt supply.
6DS4 β Nuvistor VHF triode used in TV tuners immediately prior to the introduction of solid state tuning circuits. (RCA TVs equipped with a 6DS4 tuner bore the trademark "Nu-Vista Vision"); successor of the 6CW4.
6DS8, ECH83 β Triode-heptode Local oscillator-Mixer which will operate with 12Β V anode supply, used in car radios which run directly off the 13.5 volt supply.
6DT6 β Quadrature detector used in TV audio circuits of the 1950s and early 1960s; cf. 6BN6, nonode.
6DV4 β Medium-mu Nuvistor triode for UHF oscillators; some versions had a gold-plated envelope
6DX8 β Triode pentode
6EM5 β TV Vertical Output Pentode
6ES6, EF98 β R.F. pentode which will operate with 12Β V anode supply, used as tuned R.F. amplifier in car radios which run directly off the 13.5 volt supply.
6ES8, ECC89, E89CC β Dual Triode used as cascode R.F. amplifier in TV tuners and V.H.F. receiver front ends, also used as general-purpose dual triode in test gear, similar to 6DJ8
6EZ8 β High-mu triple triode, Noval base
6FH8 β Medium-mu triode and three-anode sharp-cutoff tetrode for use in TV receivers and complex wave generators
6GK5 β Miniature V.H.F. triode (Used as V.H.F. local oscillator in some T.V. Turret Tuners)
6GM5 β Beam power pentode, identical to 7591 and 7868 with a Noval base
6GV8, ECL85 β Triode Pentode (TV vertical output)
6GW8, ECL86 β Audio Triode Pentode (audio, TV vertical output)
6GY8 β High-mu triple triode for use as oscillator, mixer, RF amplifier or AFC tube, Noval base
6HS8 β Dual-anode pentode for TV receiver sync separation service or as a two-channel VCA
6JU8A β 9Β mA, Quad diode, units 1&2 and 3&4 internally series-connected
6KM8 β Diode and three-anode sharp-cutoff tetrode for use in musical instruments, frequency dividers and complex wave generators
6LF6 β Beam power tetrode with a duodecar Compactron base and anode cap, for CRT horizontal-deflection amplifiers
6MD8 β Medium-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, B9E Novar 9-pin base
6ME5 β "Magic Eye"-type tuning indicator, miniature 7-pin base
6MK8 β Dual-anode pentode for TV receiver sync separation service or as a two-channel VCA
6MJ8 β Medium-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
6MN8 β High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
6SA7 β First pentode-triode style pentagrid converter. Octal type. Miniature version: 6BE6.
6SB7Y (octal), 6BA7 and 12BA7 (Noval) β VHF pentagrids, 1946
6SC7 β High-mu dual triode (Both sections share a single cathode)
6SK7 β Remote-cutoff pentode (Used in I.F. stages of North American radios) Miniature version: 6BD6
6SL7, ECC35 β Dual triode (Used in TV and general electronics)
6SN7, ECC32, B65, 13D2, CV1986, 6042 β Medium-mu dual triode (Used in Audio Amplifiers, Hammond Organs and Television; extensive use in World War II radar) Each section is equivalent to a 6J5. Miniature version: 12AU7
6SS7 β Remote-cutoff pentode (150Β mA heater version of the 6SK7, found in some AA6 radios as both the RF amplifier and first IF). This is the only tube to have a same-letter repetition
"7" prefix Loctal tubes
These tubes all have 6.3 volt AC/DC heaters.
7A4 β Medium-mu triode, Loctal version of type 6J5, often numbered 7A4/XXL
7A5 β Beam power pentode, Loctal version of type 6U6GT
7A6 β Dual detector diode, similar to type 6H6
7A7 β Remote-cutoff pentode, Loctal version of type 6SK7
7A8 β The only octode pentagrid converter produced in America by Sylvania, 1939. Used mostly in Philco radios.
7B4 β High-mu triode, Loctal version of types 6F5 and 6SF5
7B5 β Power pentode, Loctal version of types 6K6 and 41
7B6 β High-mu triode, dual detector diodes, Loctal version of type 75, similar to types 6AV6 and 6SQ7
7B7 β Remote-cutoff pentode
7B8 β Pentagrid converter, Loctal version of types 6A7 and 6A8
7C4 β High frequency diode
7C5 β Beam power pentode, Loctal version of type 6V6
7C6 β High-mu triode, dual detector diode
7C7 β Sharp-cutoff pentode
7E5 β Medium-mu high-frequency triode
7E6 β Medium-mu triode, dual detector diode, Loctal version of types 6R7 and 6SR7, electronically identical to miniature type 6BF6.
7E7 β Semiremote-cutoff pentode, dual detector diode, similar to types 6B7 and 6B8
7F7 β High-mu dual triode, Loctal version of type 6SL7-GT
7F8 β Medium-mu VHF triode, used as amplifier or converter
7G7 β Sharp-cutoff pentode
7G8 β Sharp-cutoff dual tetrode
7H7 β Semiremote-cutoff pentode
7J7 β Triode-heptode converter, similar to type 6J8-G
7K7 β High-mu triode, dual detector diode, similar to types 6AT6 and 6Q7
7L7 β Sharp-cutoff pentode
7N7 β Dual medium-mu triode, Loctal version of type 6SN7-GT
7Q7 β Pentagrid converter, similar to type 6SA7
7R7 β Remote-cutoff pentode, dual detector diode
7S7 β Triode-heptode converter
7T7 β Sharp-cutoff pentode
7V7 β Sharp-cutoff pentode; 7W7 but with the suppressor grid on pin 4, an internal shield on pin 5, and the cathode on pin 7
7W7 β Sharp-cutoff pentode; 7V7 but with the suppressor grid and internal shield on pin 5, and the cathode on pins 4 and 7
Note: When substituting a 7V7 for a 7W7 or vice versa, verify connections on socket pins 4 and 7; pin 5 is usually connected to the chassis
7X6 β Dual rectifier diode
7X7 β High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amplifier, often numbered 7X7/XXFM
7Y4 β Full-wave rectifier
7Z4 β Full-wave rectifier
7AB7 β Sharp-cutoff pentode
7AD7 β Power pentode
7AF7 β Dual medium-mu triode
7AG7 β Sharp-cutoff pentode
7AH7 β Remote-cutoff pentode
7AJ7 β Sharp-cutoff pentode
7AK7 β Sharp-cutoff, dual control pentode for computer service. Perhaps the first active device specifically designed for computer use.
12 volt heater tubes
12A5 β Power pentode. UX7 base. Center-tapped 12.6Β V/300Β mA resp. 6.3Β V/600Β mA heater. Mostly used in pre-war car radios.
12A7 β Power pentode, rectifier diode. Pentode section is similar to type 38. Diode has a low power rating β 120 volt, 30Β mA β that limits the number of tubes that can be tied to its B+ circuit. Used in one-tube portable phonographs and a few two- and three-tube radios. Forerunner of such types as 32L7-GT, 70L7-GT and 117L7-GT. UX7 base with top cap. Not related to types 2A7 and 6A7.
12B4A β Low-mu triode, noval base.
12J5WGT β Heater cathode type, medium-mu triode, identical to 6J5WGT except heater characteristics
12K5 β Low-anode voltage tetrode with a space charge grid
12U5G β Tuning indicator identical to 6U5G except heater characteristics
12Z3 β Half-wave rectifier, UX4 base
12AB5 β Beam Power Tube
12AC10 β Compactron High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
12AE10 β Compactron Beam power tube and sharp-cutoff pentode
12AL5 β Dual diode (similar to 6AL5 except for heater)
12AT6 β Dual diode/triode (Commonly replaced by 12AV6 in consumer radios)
12AT7, ECC81, 6060, B309, M8162 β High-mu dual triode. Commonly used as R.F. amplifier/mixer in VHF circuits.
12AU7, ECC82, 6067, B329, M8136 β Medium-mu dual triode. Two 6C4/EC90s in one envelope; however, it is only specified as an audio frequency device. Commonly used in audio applications and TV receivers.
12AV6 β Dual diode/High-mu triode (see also: 6AV6)
12AV7, 5965 β Medium-mu dual triode. Principally designed for VHF amplifier/mixer operation.
12AX7, ECC83, 6057, B327, M8137 β High-mu dual triode. Very similar to triode section of 6AV6. Commonly used in high-gain audio stages and as power inverters in class A/B amplifiers.
12AW7 β See 12DW7 below. Called AW by some, but proper name is DW.
12AY7 β Dual Triode. Medium gain but low noise, intended for low-level/preamplifier use.
12AZ7 β Dual Triode. Medium-mu, AF Amplifier, or combined oscillator and mixer, Noval base.
12BA6 β Remote-cutoff pentode, 6BA6/EF93 with a different heater
12BE6 β Pentagrid converter, 6BE6/EK90 with a different heater
12BH7 β Dual Triode, Medium-mu, designed for use in equipment having series heater-string arrangement.
12BY7 β Video Amplifier Pentode
12DT5 β Beam Power Pentode
12DT6 β Sharp-cutoff pentode
12DW7/ECC832, 7247 β Dissimilar triodes. One half 12AX7 value, other half 12AU7 value.
12EG6 β Pentagrid converter, both grids 1 and 3 are sharp-cutoff, has 12.6 volt anode and screen grid voltage, for use in car radios
12FA6 β Low-anode voltage, car radio version of 12BE6 pentagrid converter
12FQ8 β Common-cathode, dual split-anode triode for use in musical instruments, frequency dividers and complex wave generators
12FX8 β Low-anode voltage, triode-heptode converter for car radios
12GA6 β Similar to type 12FA6, but with lower conversion transconductance
12MD8 β Medium-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, B9E Novar 9-pin base
12MN8 β High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, B12C Duodecar 12-pin base
12SA7 β Pentagrid converter (Octal version of 12BE6)
12SK7 β Remote-cutoff Pentode (Octal version of 12BA6)
12SQ7 β Dual diode, triode (Octal version of 12AV6)
"14" prefix Loctal tubes
These tubes all have 12.6 volt AC/DC heaters
14A4 β Medium-mu triode, Loctal version of type 12J5
14A5 β Beam power pentode
14A7 β Remote-cutoff pentode, often numbered 14A7/12B7
14B6 β High-mu triode, dual detector diode, similar to types 12AV6 and 12SQ7
14B8 β Pentagrid converter, Loctal version of type 12A8
14C5 β Beam power pentode, Loctal version of type 12V6-GT
14C7 β Sharp-cutoff pentode
14E6 β Medium-mu triode, dual detector diode, Loctal version of 12SR7
14E7 β Semiremote-cutoff pentode, dual detector diode, similar to type 12C8
14F7 β High-mu dual triode, Loctal version of type 12SL7-GT
14F8 β Medium-mu VHF triode, used as amplifier or converter
14H7 β Semiremote-cutoff pentode
14J7 β Triode-heptode converter
14N7 β Dual medium-mu triode, Loctal version of type 12SN7-GT
14Q7 β Pentagrid converter, similar to type 12SA7
14R7 β Remote-cutoff pentode, dual detector diode
14S7 β Triode-heptode converter
14W7 β Sharp-cutoff pentode
14X7 β High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amplifier
14Y4 β Dual rectifier diode
14AF7 β Dual medium-mu triodes, often numbered 14AF7/XXD
25 volt series heater tubes
25A6 β Power pentode, octal version of type 43
25C5 β Beam Power Pentode (Identical to the 50C5 but with a 25Β V 300Β mA heater)
25F5 β Beam Power Pentode (Identical to the 50C5, but with a 25Β V 150Β mA heater, used in some AA5 type radios using push-pull output)
25L6 β Beam-power pentode (Except for heater, electrically identical to type 50L6)
25Z5 β Dual rectifier diode
25Z6 β Octal version of 25Z5
35 volt series heater tubes
35A5 β Beam Power Tube (Loctal, Similar to 35L6)
35B5 β Beam power tube
35C5 β Identical to 35B5 except for basing ("pin-out") arrangement (HL92)
35L6-GT β Beam power pentode similar to, but not electronically identical to, types 25L6-GT and 50L6-GT
35W4 β Rectifier diode
35Y4 β Rectifier Diode (Loctal, similar to 35Z5)
35Z3 β Rectifier Diode (Loctal, Similar to 35Z4)
35Z4-GT β Rectifier diode
35Z5-GT β Similar to 35Z4-GT, but equipped with a heater tap used to power a pilot light
35DZ8 β High-mu Triode/Beam Power tube (Like the 35HB8, used for audio)
35HB8 β Triode/Beam Power tube (Used primarily as both the audio amplifier and output)
50 volt series heater tubes
50A5 β Beam Power Tube (Loctal, similar to 50L6)
50B5 β Beam power tube, similar to 35B5 but with 50 volt heater
50C5 β Similar to 35C5 but with 50 volt heater, and 50B5 except for basing ("pin-out") arrangement
50L6 β Beam power tube (see also 25L6)
50X6 β Dual Diode (Loctal, commonly used as a rectifier-doubler)
50DC4 β Rectifier diode (Similar to 35W4 except for heater)
50EH5 β Beam Power tube, (Similar to 50C5 but with higher gain, some radios that use this tube do not have an audio amplifier section.)
50HK6 β Power pentode (Filament is tapped for use with a dial lamp)
117 volt heater tubes
All of the following tubes are designed to operate with their heaters connected directly to the 117 volt (now 120 volt) electrical mains of North America. All of them use indirectly heated cathodes. All of them incorporate at least one rectifier diode.
Rectifier diode β Beam power pentode combinations
117L7GT
117M7GT
117N7GT
117P7GT
Rectifier tubes
117Z3 β Single diode, 7-pin miniature version of 117Z4GT
117Z4GT
117Z6GT β Dual diode, can be used as a voltage doubler
Other tubes with nonstandard heater voltages
The tubes in this list are most commonly used in series-wired circuits.
5J6 β General purpose RF dual triode with common cathodes, a 6J6 with a 4.7Β volt/600Β mA controlled warm-up heater
8B10 β Compactron Dual triode and dual diode
2AF4 β UHF triode oscillator
2BN4 β VHF triode
2CW4 β Nuvistor high-mu VHF triode, 6CW4 with a 2.1Β volt/450Β mA heater; used in TV receivers with series heater strings
2CY5 β VHF sharp-cutoff tetrode
2EA5 β VHF sharp-cutoff tetrode
2EN5 β Dual diode
2ER5 β VHF triode
2ES5 β VHF triode
2EV5 β VHF sharp-cutoff tetrode
2FH5 β VHF triode
2FQ5 β VHF triode
2FV6 β VHF sharp-cutoff tetrode
2FY5 β VHF triode
4CB6 β Sharp-cutoff pentode
7AU7 β Medium-mu Dual triode with a center-tapped 7.0/3.5Β V heater, like the 12AU7
7KY6 β Sharp-cutoff frame-grid pentode with a 7.3 volt nominal heater voltage for use as video output tube in TV receivers, Noval base
8AC10 β Compactron High-mu triple triode for use as NTSC chroma signal demodulator matrix in analog color TV receivers, 12-pin base
8FQ7/8CG7 β Dual triode (8Β V version of the common 6CG7)
10DE7 β Dual triode (dissimilar triode sections)
11DS5 β Beam Power tube (11Β V heater version of the 50B5/35B5)
13CW4 β Nuvistor used as a preamplifier in Neumann condenser microphones U-47 and U-48 after the production of the VF14 ceased
17EW8, HCC85 β Dual High-mu triode
18FX6 β Pentagrid converter (18Β V version of the 12BE6)
18FY6 β Dual diode/triode (18Β V version of the 12AV6)
34GD5 β Beam power tube (34Β V version of the 35C5/50C5)
36AM3 β Half-wave rectifier (36Β V version of the 35W4)
38HE7 β Compactron Diode and beam power tube
38HK7 β Compactron Diode and beam power tube
List of RMA professional tubes
1B23 β 20Β kW, 400 to 1500Β MHz Gas-filled, cold-cathode Transmit/Receive Tube (TR cell)
1B41 β Gas-filled, cold-cathode 9.5Β kV, 450Β A spark gap
1B45 β Gas-filled, cold-cathode 14Β kV, 450Β A spark gap
1B49 β Gas-filled, cold-cathode 12Β kV, 450Β A spark gap
1C21 β Gas-filled, 25Β mAavg, 100Β mApeak, triode thyratron
1D21 β Strobotron Gas-filled, 50Β mAavg, 5Β Apeak, luminescent tetrode thyratron for use as a stroboscope lamp
1P21 β 9-stage Photomultiplier, spectral S4 response, 11-pin base
1P25 β Infrared image converter used in World War II night vision "sniperscopes".
1P29 β Gas-filled phototube, spectral S3 response, 4-pin base
1P39 β Vacuum Phototube, spectral S4 response, 4-pin base
1S22 β 10Β kV, 20Β A Vacuum SPDT switch
2C21 β Dual triode, indirectly heated, 7-pin base plus a single top cap for one of the grids
2C22 β Transmitting triode, indirectly heated, Octal base plus dual top cap for grid and anode
2C36 β Rocket-type disk-seal UHF triode with an internal feedback circuit between cathode and anode, for use as UHF oscillator up to 1.75Β GHz
2C37 β Rocket triode for use as SHF oscillator up to 3.3Β GHz
2C39A β Oil can-type disk-seal UHF power triode with glass spacers up to 3Β GHz, Panode = 100Β W
2C39B β 2C39A with ceramic spacers
2C40 β Lighthouse-type disk-seal UHF power triode for continuous operation, Panode = 6.5Β W at 3370Β MHz
2C41 β Oil can UHF power triode for pulsed operation, 2200Β Wpeak at 3Β GHz
2C42 β Lighthouse UHF power triode for pulsed operation, 1750Β Wpeak at 1050Β MHz; improved 446
2C43 β Lighthouse UHF power triode, indirectly heated, up to 3.37Β GHz, 6-pin Octal base
2C46 β Lighthouse UHF power triode
2C51 β Dual shielded triode, indirectly heated, 6-pin Octal base
/EN91 (PL21, PL2D21, CV797) β 100Β mAavg, 500Β mApeak, 10Β Asurge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for relay and grid-controlled rectifier service, used in jukeboxes and computer equipment.
2E22 β 53Β W Power pentode, 5-pin base with anode on top cap
2E26 β Popular amateur 5.3Β W VHF beam power tetrode up to 175Β MHz, octal base
β 10Β W Directly heated beam power tetrode with deflection screens available on separate pin, miniature 7-pin base
2E31 β Subminiature, directly heated, fully shielded sharp-cutoff RF/IF pentode, 5-pin all-glass wire-ended, FL
2E32 β Similar to 2E31, SL
2E35 β 6Β mW Subminiature directly heated power pentode, 5-pin all-glass wire-ended, FL
2E36 β Similar to 2E35, SL
2E41 β Diode, pentode, FL
2E42 β Similar to 2E42, SL
2F21 β Indirectly heated hexode monoscope, Indian Head test pattern, 6-pin base with dual top caps for grid4 and anode
2G21 β Directly heated triode-heptode mixer, 7-pin all-glass wire-ended
2G41 β Triode-heptode converter, FL
2G42 β Similar to type 2G42, SL
2H21 β Phasitron, a magnetically controlled beam-deflection phase modulator tube similar to the 5593, used in early FM broadcast transmitters
2J30 to 2J34 β 300Β kW S-band Magnetrons
2J55 and 2J56 β 40Β kW X-band Magnetrons for use as pulsed oscillator
2K25 β 25Β mW 8.5 to 9.66Β GHz Reflex Klystron
2K50 β 15Β mW 23.5 to 24.5Β GHz Reflex Klystron
2P23 β Early image orthicon TV camera tube.
3B28 β Xenon half wave rectifier; ruggedized replacement for mercury vapor type 866.
3C22 β Disk-seal UHF power triode, Panode = 125Β W with forced-air cooling, 1.4Β GHz
3C23 β 1.5Β Aavg, 6Β Apeak, Mercury-vapor triode thyratron, 4-pin base with anode top cap
3C45 β 45Β mAavg, 1.5Β ARMS, 35Β Apeak, Half-indirectly heated hydrogen triode thyratron, 4-pin base with anode top cap
3D21 β Indirectly heated beam power tetrode, Octal base with anode top cap
3D22 β Gas-filled, 800Β mAavg, 8Β Apeak, tetrode thyratron, 7-pin base
3E29 β Dual beam power tube used in radar equipment; a pulse rated variant of the earlier 829B, Septar 7-pin base with dual anode top cap.
4B32 β 10Β kV, 1.25Β Aavg, 5Β Apeak Xenon half wave rectifier
4D21 (6155, Eimac 4-125A) β 125Β W Glass VHF beam power tetrode
4E27 β 125Β W Glass radial-beam power pentode
4J31 to 4J35 β 1Β MW S-band Magnetrons
5B24 β Tungar bulb, a low-voltage, mercury-vapor, full wave rectifier for charging 60-cell lead-acid batteries at 6Β A; 2.5Β V, 24Β A heater
5C22 β Half-indirectly heated, hydrogen triode thyratron for radar modulators.
5D22 (6156, Eimac 4-250A) β 250Β W, 110Β MHz Glass beam power tetrode
5J26 β 500Β kW, 1.22 to 1.35Β GHz S-band Magnetrons
6C21 β Triode radar modulator for "hard tube" pulsers.
7C23 β 120Β kW Power triode for high voltage pulse operation.
8D21 β Internally water cooled dual tetrode used in early VHF TV transmitters.
9C21 β 100Β kW Water-cooled power triode, directly heated, 4-pin base with dual top caps for grid and anode
List of EIA professional tubes
Note: Most of these are special quality versions of the equivalents given. Some manufacturers preceded the EIA number with a manufacturer's code, as explained above.
5000s
5331, 5332, 5514 β Directly heated power triodes, 4-pin base with anode top cap
5556 β Directly heated power triode, 4-pin base
5593 β Phasitron, a magnetically controlled beam-deflection phase modulator tube similar to the 2H21, used in early FM broadcast transmitters
5608 β Dual power triode, designed for use with AC anode voltage and critical grid leak requirements
5651 β 86-volts, cold-cathode, glow-discharge voltage reference, 7-pin miniature base
5654, CV4010, 408A β VHF pentode; common in vintage radar IF amplifiers; premium version of 6AK5, EF95, 6J1P (6Π1Π)
5678 (CK5678 Raytheon) β 5 leads subminiature shielded pentode for RF applications
5691 β Special Red ruggedized long-life high-mu triode for industrial applications
5692 β Special Red ruggedized long-life medium-mu triode for industrial applications
5693 β Special Red ruggedized long-life sharp-cutoff pentode for industrial applications
5703 β Subminiature UHF triode, all-glass wire-ended
5704 β Subminiature diode, all-glass wire-ended
5727 β 650Β V, 100Β mAavg, 500Β mApeak, 10Β Asurge Indirectly heated tetrode thyratron, positive starter voltage, miniature 7-pin base
5729 β Beam-deflection, 30-channel analog multiplexer for telecomms transmitting channel banks, internal electrostatic focusing and deflection to determine through which one out of 30 grids the electron beam passes to the common anode. Cf. 5738, 6090, 6091, 6170, 6324
5731 β Narrow-tolerance selected 955 Acorn triode for use in Radiosonde weather balloon transmitters
5734 β Mechano-electronic displacement sensor; a vacuum triode with its anode mounted on a shaft that extends through a thin, flexible metal diaphragm; shaft movement is reflected in anode current; Fres = 12Β kHz
5738 β Beam-deflection, secondary emission, 25-channel analog multiplexer, internal electrostatic focusing and deflection to determine which one out of 25 individually controllable dynodes receives the electron beam controlled by a common grid. Cf. 5729, 6090, 6091, 6170, 6324
5749β RF pentode; premium version of 6BA6, EF93, W727
5750 β Heptode mixer; premium version of 6BE6, EK90, X727
5751 β Low-noise avionics dual triode with separate cathodes
5814A β Industrial, computer-rated version of 12AU7/ECC82
5836, 6BL6 β Sutton tube, a reflex klystron used as a 250Β mW CW microwave source, 1.6 to 6.5Β GHz depending upon an external cavity. 4-pin peewee base with cavity contact rings and top cap
5837, 6BM6 β Sutton tube used as a 150Β mW CW microwave source, 550Β MHz to 3.8Β GHz depending upon an external cavity. 4-pin peewee base with cavity contact rings and top cap
5840 β Subminiature sharp-cutoff RF pentode, all-glass wire-ended
5845 β Dual directly heated saturated-emission diode. Acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits.
5876A β Glass pencil-type disk-seal UHF power triode up to 2Β GHz
5899 β Subminiature semi-remote-cutoff pentode, low noise, all-glass wire-ended
5930 β Ruggedized, directly heated power triode, 4-pin base
5962 β 700Β V/2...55Β ΞΌA Corona voltage reference, miniature 7-pin base with anode top cap
5963, 5964, 5965 β Dual triode, designed for high speed digital computers, has a high zero-bias anode current, industrial/computer-rated versions of 12AV7
5998, 6336A, 6394, 6520, 6528, 7802 β Dual power triodes, designed for series voltage regulator applications
6000s
6047 β Additron, a triple-control grid, split-anode tetrode for use as a single-bit digital full adder (technically a hexode)
6057, M8137 β High-mu dual triode; premium version of 12AX7, ECC83, B339
6059 β Low-microphonics pentode; premium version of 6BR7
6060, M8162 β High-mu dual triode; premium version of 12AT7, ECC81, B309
6064, M8083 β R.F. pentode; premium version of 6AM6, EF91, Z77
6067, M8136 β Medium-mu dual triode; premium version of 12AU7, ECC82, B329
6080 β Very-low impedance dual power triode, designed for series voltage regulator applications, now popular for output transformerless audio amplifiers; premium version of 6AS7
6082 β Ruggedized, indirectly heated power triode, octal base
6090 β Beam-deflection, 18-channel analog demultiplexer for telecomms receiving channel banks, internal electrostatic focusing and deflection to determine which one out of 18 anodes receives the electron beam controlled by a common grid. Cf. 5729, 5738, 6091, 6170, 6324
6091 β Beam-deflection, 25-channel analog multiplexer for telecomms transmitting channel banks, internal electrostatic focusing and deflection to determine through which one out of 25 grids the electron beam passes to the common anode. Cf. 5729, 5738, 6090, 6170, 6324
6146 β 60Β MHz, 120Β W AF/RF/VHF beam power pentode
6146B (8298A) β Improved version of 6146, 6146A and 8298.
6170 and 6324 β Beam-deflection, 25-channel analog multiplexer for telecomms transmitting channel banks, external focusing and deflection by a multiphase, rotating magnetic field to determine through which one out of 25 grids the electron beam passes to the common anode. Cf. 5729, 5738, 6090, 6091
6173 β Pencil-type disk-seal UHF diode up to 3.3Β GHz
6196 β Directly heated dual, compensating electrometer tetrode with space charge grids for use in the 2 branches of a differential-in, differential-out bridge circuit
6218/E80T (CV5724) β Modulated, single-anode beam deflection tube for pulse generation up to 375Β MHz; shock resistant up to 500Β g
6263 β Pencil-type disk-seal UHF power triode up to 500Β MHz, Panode = 8Β W
6351 β Secondary emission pentode for wide band RF amplifiers
6353 β 19.3Β kV/25...1000Β ΞΌA Corona voltage reference, miniature 7-pin base with anode top cap
6361 β Convectron, an inclinometer tube that senses tilt from the vertical by means of different gas convections around a heating wire in a glass envelope, of two 6361s aligned in a 90Β° V-shaped position to each other and the heating wires connected in a bridge circuit
6391 β Subminiature low-microphonics pentode, 8-pin all-glass wire-ended
6441 β 650Β V, 100Β mAavg, 300Β mAsurge Tacitron, a grid turn-off hydrogen thyratron with a grid that forms a shield around both the cathode and anode and separates the two by a wire mesh, so the arc discharge can be extinguished by a negative grid that surrounds the positive anode with a field of opposing polarity and inhibits conduction, taking over part of the anode current during deionisation β similar to today's GTOs; Octal base
6462 β Magnetic pickup tube, a 1-axis beam-deflection magnetometer with approx. resolution; an electron beam is electrostatically centered between two anodes while no magnetic field is present; the magnetic field to be detected will then deflect the beam more towards one of the anodes, resulting in an imbalance between the two anode currents
6550 β 20Β W AF beam tetrode for high fidelity amplifiers
6550A β 6550 with a 42 watt anode
6571 β Williams-type computer memory tube
6577 β Typotron, a charactron for text mode video rendering in early computer monitors
6700 β 200Β ns Decade counter Magnetron Beam Switching Tube, 6.3Β V, 300Β mA heater
6701 β Low-voltage 500Β ns decade counter Magnetron Beam Switching Tube, 6.3Β V, 300Β mA heater
6703 β 500Β ns Decade counter Magnetron Beam Switching Tube, 6.3Β V, 300Β mA heater
6704 β 100Β ns Decade counter Magnetron Beam Switching Tube with internal spade load resistors, 6.3Β V, 300Β mA heater
6710, 6711, 6712 (High current), 6714 (Low voltage) β 2Β MHz Decade counter Beam-X Switch, 6.3Β V heater
6762 β Wamoscope, a TWT/CRT combination used to directly visualize an incoming microwave signal by electron velocity-sorting
6835, 7570, 7571 β Single-electron gun recording storage tube, an analog video frame freezer tube. This was achieved by a CRT that writes the video image onto a thin, dielectric target and subsequently can read the generated charge pattern up to 30000 times from that target, producing a video signal containing a static shot that resembles a still photograph
6846 β Gas-filled, three-cathode 1-bit binary counter or switching tube, Miniature 7-pin base
6877, 7233 β Power triodes, designed for series voltage regulator applications
6900 β Dual power triode for pulse applications in missiles, avionics and industrial systems; noval base
6922 (E88CC, industrial version of 6DJ8/ECC88)
6973 β Power pentode similar in shape, size, and base to the EL84/6BQ5, but with a high gain for more than double the output range. Popular in some makes of 1960s era guitar amplifiers, though rarely implemented in modern times.
7000s
7025 β Low-hum, noise and microphonics version of 12AX7
7027 β AF Power pentode, improved 6L6 with a 25 Watt anode and different pinout
7027A β Improved 7027 with a 35 watt anode
7077 β Miniature ceramic/metal disk-seal UHF triode
7105 β 12.6-volts version of 6080
7189/6BQ5/EL84 β AF Beam power pentode
7189A β Improved 7189
7199 β Triode-pentode, noval base. Similar to 6U8.
7229, 7230, 7231, 7232, 7439, 7440, 7441, 7595, 7596, 7597, 7598, 7599, 7600, 7602 β Krytrons, cold-cathode gas-filled trigger tubes with a primer electrode for use as a very high-speed, high-surge current switchΒ β second source to EG&G
7236 β Dual power triode for use as long-life power amplifier in computer applications
7241, 7242 β Triple-cathode power triodes, designed for hi-rel cathode follower series voltage regulator applications where the cathode is split into 3 sections connected together via balancing resistors to equalize the emission along the cathode
7266 β Miniature ceramic/metal disk-seal UHF diode
7289 β 3Β GHz, 40Β W UHF planar power triode
7308/E188CC β Premium version of 6922
β Beam deflection tube, used as balanced modulator/mixer up to 100Β MHz
7414 β Time Totalizer, a metal-vapor coulometer, a cold-cathode gas-discharge tube where metal is constantly sputtered off the cathode and deposited on a collector element whose resistance therefore decreases with elapsed time
7430 β Flat-envelope version of the 6AK5/EF95 sharp-cutoff pentode for use on PCBs in Radiosonde weather balloon transmitters
7548 β Secondary emission hexode for pulse generator and pulse amplifier applications
7551 β Noval-base beam power pentode with 12-15 volt heater. 6.3 volt heater version was 7558. Used in telephony, RF amplification, and more rarely AF amplification.
7554 β Ceramic/metal pencil-type disk-seal SHF power triode up to 5Β GHz
7572, 7575, 7702 β Dual-electron gun recording storage tube, a realtime analog video frame freezer tube with simultaneous R/W, and storing capability. This was achieved by a CRT/camera tube combination; the CRT part writes the video signal onto a thin, dielectric target, which can hold the generated charge pattern for many hours; the camera part reads the charge pattern from the back side of this target, producing a video signal containing a static shot that resembles a still photograph
7586 β First Nuvistor available on the market, medium-mu triode
7587 β Nuvistor Sharp cutoff tetrode
7591 β Beam power pentode, octal base. Found in many guitar amps made by Gibson and Ampeg.
7688, 7690 (Medium-mu), 7689 (high-mu) β triple triodes
7699 β Dual tetrode for wide band push-pull amplifiers
7762 β Shock-proof avionics AF beam power pentode
7763 β Beam deflection tube, used as IF amplifier/limiter where a constant phase shift over a wide range of input signal amplitudes is required
7768 β Miniature ceramic/metal disk-seal planar SHF triode up to 4Β GHz
7868 β Beam power pentode, B9E Novar base version of 7591. Found in many of the once popular Challenger series PA amps made by Bogen Communications, also found in some guitar amplifiers made by Ampeg.
7895 β Improved 7586 Nuvistor with higher mu
8000s
8011 β Micropup-type UHF power triode up to 600Β MHz
8056 β Nuvistor triode for low supply voltage
8058 β Nuvistor triode with grid on envelope and an anode cap, for grounded-grid UHF circuits
8069 β 8Β kV/23...1000Β ΞΌA Corona voltage reference, cathode cylinder and anode top cap
8089 β 1.6Β kV/20...800Β ΞΌA Corona voltage reference, 2-pin all-glass wire-ended
8090 β 3.5Β kV/50...1000Β ΞΌA Corona voltage reference, Noval base with anode top cap
8091 β 4Β kV/50...1000Β ΞΌA Corona voltage reference, Noval base with anode top cap
8122 β Forced-air cooled, 300Β W@470Β MHz beam power tetrode
8254 β Subminiature triode, low Cg for instrumentation, all-glass wire-ended
8256 β 3.5Β kV/35...1900Β ΞΌA Corona voltage reference, 2-pin all-glass wire-ended
8257 β 1.2Β kV/15...750Β ΞΌA Corona voltage reference, 2-pin all-glass wire-ended
8393 β Nuvistor Medium-mu triode, used in Tektronix oscilloscopes, 13.5Β Volt heater
8469 β 400Β V/5...400Β ΞΌA Corona voltage reference, 2-pin all-glass wire-ended
8506 β Miniature ceramic/metal disk-seal planar UHF triode
8514 β 1Β kV/10...800Β ΞΌA Corona voltage reference, 7-pin with anode top cap
8515 β 1.6Β kV/20...950Β ΞΌA Corona voltage reference, 7-pin with anode top cap
8526 β Nuvistor-type medium-mu dual triode
8873 β 500Β MHz, 200Β W anode dissipation power triode
8874 β 500Β MHz, 400Β W anode dissipation power triode
8875 β 500Β MHz, 300Β W anode dissipation power triode
8877 = 3CX1500A7 β Ceramic, forced air cooled, 1.5Β kW power triode
8974 (X-2159) β Giant water-cooled megawatt-class tetrode used for very high-power broadcast and industrial service; possibly the most powerful tube ever commercially produced
List of European MullardβPhilips tubes
List of Pro Electron professional tubes
Note: Typecode explained above.
X - Electro-optical devices
XA
XA1003 β Phototube, caesium-on-oxydated-silver cathode, 2-pin all-glass wire-ended
XG
XG2000 β Image converter for x-ray diagnostics
XL
XL7900 β Vibrating-capacitor chopper front end for dosimeters, electrometers, pH meters etc., Magnoval base with gold-plated pins
XM
XM1000 β Nimo tube, directly heated cathode-ray 1-digit numeric display tube, decimal points on both sides, hence 12 stenciled electron guns, top-viewing, green, 15Β mm high Futura Medium font, oval envelope for easy horizontal stacking, 14-pin base
XP
XP1000 β 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal (14-pin) base
XP1001 β 10-stage photomultiplier for gamma ray scintillation spectrometry, Sb-Cs cathode, Ag-Mg-O-Cs dynodes
XP1002 β 10-stage photomultiplier, blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1003 β 10-stage photomultiplier with quartz window, UV/blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1004 β 10-stage photomultiplier with quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1005 β 10-stage Ag-O-Cs (800Β±100Β nm) photomultiplier, IR/red-sensitive Ag-O-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1010 β 10-stage photomultiplier for r-ray and gamma ray scintillation spectrometry, selected 150AVP for low noise and resolution, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, duodecal (12-pin) base
XP1011 β 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, shock and vibration-proof, duodecal base
XP1020 β 12-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, 100Β Ξ© output, duodecal (20-pin) base
XP1021 β 12-stage photomultiplier, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, 50Β Ξ© output, duodecal base
XP1023 β 12-stage photomultiplier with quartz window Sb-Cs cathode, Ag-Mg-O-Cs dynodes, UV/blue-sensitive, 50Β Ξ© output, duodecal base
XP1030 β 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal (14-pin) base
XP1031 β 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, for gamma ray scintillation spectrometry
XP1032 β 10-stage photomultiplier with 3Β mm quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1033 β 10-stage photomultiplier with 10Β mm quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
XP1040 β 14-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, concave window, duodecal base
XP1110 β Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
XP1111 β Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, wire-ends
XP1113 β 6-stage Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
XP1114 β 4-stage Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
XP1115 β Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, wire-ends, shock and vibration-proof
XP1116 β Photomultiplier, red-sensitive Ag-O-Cs cathode, Ag-Mg-O-Cs dynodes, shock and vibration-proof
XP1117 β 9-stage photomultiplier, blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes
XP1118 β Photomultiplier with quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
XP1120 β 17-stage photomultiplier for x-ray (Ξ» > 200Β pm) or UV (Ξ» < 150Β nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
XP1121 β 17-stage photomultiplier for ion (> 10Β keV) or electron (0.1...10Β keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
XP1122 β 17-stage photomultiplier for x-ray (Ξ» > 200Β pm) or UV (Ξ» < 150Β nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
XP1123 β 17-stage photomultiplier for ion (> 10Β keV) or electron (0.1...10Β keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
XP1130 β 17-stage photomultiplier for x-ray (Ξ» > 200Β pm) or UV (Ξ» < 150Β nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
XP1131 β 17-stage photomultiplier for ion (> 10Β keV) or electron (0.1...10Β keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
XP1140 β 6-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
XP1141 β 7-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
XP1180/52AVP β 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
XP1240 β Photomultiplier
XQ
XQ1023 β Camera tube
XQ1029R β Camera tube, red channel
XQ1032 β 1" Vidicon; magnetic focusing and deflection
XQ1053 β Camera tube
XQ1072 β 1" Plumbicon
XQ1073 β XQ1072 with higher resolution and improved low level contrast
XQ1200 β Vidicon, silicon target
XQ1270 β " Vidicon; Overall length 108mm (")
XQ1272 β " Vidicon
XQ1274 β " Newvicon, magnetic focussing and deflection, ZnSe+CdZnTe target
XQ1275 β Vidicon, silicon target
XQ1276 β XQ1274 with high sensitivity into the near infrared
XQ1277 β XQ1275 with high sensitivity into the near infrared
XQ1278 β XQ1275 with better geometry and uniform signal
XQ1285 β 1" Vidicon; magnetic focusing and deflection, precision electron gun
XQ1290 β 1" Resistron camera tube
XQ1293 β Camera tube
XQ1300 β Saticon Camera Tube
XQ1340 β Low-light Vidicon
XQ1371 β Resistron
XQ1380 β XQ1274 with radiation resistant (anti-browning) faceplate
XQ1381 β " Newvicon; electrostatioc focusing and magnetic deflection with radiation-resistant (anti-browning) faceplate
XQ1395 β High-resolution Resistron camera tube
XQ1410B/G/R β Plumbicon for color TV broadcast
XQ1412 β 6/5" Plumbicon; low lag, unity gamma matched to P20 phosphor
XQ1413B/G/R β Plumbicon for color TV broadcast
XQ1415B/G/R β Plumbicon for color TV broadcast
XQ1427 β " Plumbicon; low lag
XQ1427B/G/R β Plumbicon for color TV broadcast
XQ1430B/G/R β Plumbicon for color TV broadcast
XQ1435B/G/R β Plumbicon for color TV broadcast
XQ1440 β 1" Newvicon, separate mesh, ZnSe+CdZnTe target
XQ1500B/G/R β Plumbicon for color TV broadcast
XQ1505B/G/R β Plumbicon for color TV broadcast
XQ1560 β 1" Saticon
XQ1565 β 1" Saticon
XQ1570 β 1" Saticon
XQ1575 β 1" Saticon
XQ1585 β 1" Saticon
XQ1600 β " Vidicon; separate mesh, electrostatic focusing and magnetic deflection
XQ1601 β " Newvicon; separate mesh, electrostatic focusing and magnetic deflection
XQ2070/02B/G/R β Plumbicon for color TV broadcast
XQ2070/05B/G/R β Plumbicon for color TV broadcast
XQ2075/02B/G/R β Plumbicon for color TV broadcast
XQ2075/05B/G/R β Plumbicon for color TV broadcast
XQ2172 β 1" Plumbicon; wide dynamic range matched to digital radiography applications
XQ2182 β 1" Plumbicon; wide dynamic range matched to digital radiography applications
XQ2427B/G/R β Plumbicon for color TV broadcast
XQ3070/02B/G/R β Plumbicon for color TV broadcast
XQ3070/05B/G/R β Plumbicon for color TV broadcast
XQ3075/02B/G/R β Plumbicon for color TV broadcast
XQ3075/05B/G/R β Plumbicon for color TV broadcast
XQ3427B/G/R β Plumbicon for color TV broadcast
XQ3430B/G/R β Plumbicon for color TV broadcast
XQ3435B/G/R β Plumbicon for color TV broadcast
XQ3440B/G/R β Plumbicon for color TV broadcast
XQ3445B/G/R β Plumbicon for color TV broadcast
XQ3457B/G/R β Plumbicon for color TV broadcast
XQ3467B/G/R β Plumbicon for color TV broadcast
XQ3477B/G/R β Plumbicon for color TV broadcast
XQ3487B/G/R β Plumbicon for color TV broadcast
XQ3550B/G/R β Plumbicon for color TV broadcast
XQ3555B/G/R β Plumbicon for color TV broadcast
XQ4187B/G/R β Plumbicon for color TV broadcast
XQ4502 β 2" Plumbicon; Highest resolution, low lag
XQ5002 β 2" Plumbicon; Electrostsatic deflection for improved corner resolution, low output capacitance
XQ7002 β 1" Plumbicon; Low output capacitance
XQ8002 β 1" Plumbicon
XQ9002 β 1" Plumbicon
XR
XR1000 β Monoscope, test pattern specified by suffix
XX
XX1000 β 2-stage image intensifier
XX1010 β Image intensifier
XX1020 β Image intensifier
XX1030 β Image intensifier
XX1050 β Image intensifier
XX1060 β Image intensifier
XX1066 β 1. Gen. 3-stage image intensifier
XX1140 β 1. Gen. 3-stage image intensifier
XX1190 β 1. Gen. inverter, 1-stage image intensifier
XX1192 β 1. Gen. inverter, 1-stage image intensifier
XX1200 β 1. Gen. inverter, 1-stage image intensifier
XX1211 β 1. Gen. inverter, 3-stage image intensifier
XX1270 β 1. Gen. inverter, 2-stage image intensifier
XX1400 β 2. Gen. inverter, 1-stage image intensifier
XX1430 β 1. Gen. inverter, 1-stage image intensifier
XX1510 β 1. Gen. 3-stage image intensifier
XX1610 β 2. Gen. image intensifier
XX1800 β 2. Gen. proximity focused, 1-stage image intensifier
Y - Vacuum tubes
YA
YA1000 β 5Β kV, 5mA, Directly heated saturated-emission diode with pure-metal cathode for use in RMS converters of AC voltage/current stabilizer circuits, noval base
YD
YD1000 β 45Β kW, Water-cooled RF power triode
YD1001 β 35Β kW, Air-cooled RF power triode
YD1012 β 360Β kW, Vapor-cooled RF power triode
YD1130 β 400Β W, Air-cooled, linear RF/AF power triode
YD1252 (RS 2051 V) β 180Β kW, Water-cooled, modulator power triode
YD1300 β 300Β W, Air-cooled, UHF power triode
YD1301 β 50Β W, Air-cooled, UHF power triode
YD1302 β 300Β W, Air-cooled, UHF power triode
YD1332 β 1.8Β kW, Air-cooled, UHF power triode
YD1333 β 900Β W, Air-cooled, UHF power triode
YD1334 β 1.8Β kW, Air-cooled, UHF power triode
YD1335 β 1.9Β kW, Air-cooled, UHF power triode
YD1336 β 1.8Β kW, Air-cooled, UHF power triode
YD1342 β 30Β MHz, 530Β kW, Water-cooled RF power triode
YD1352S (8867, DX334) β 5Β MHz, 2Β kW, Water-cooled Neotron, a gridless field-effect tube where a magnetically focused electron beam is modulated by varying the voltage of a gate electrode surrounding it. Used as RF power amplifier or oscillator
YG
YG1000 β Directly heated electrometer tetrode with an oxide cathode and a space charge grid, grid current β€600Β fA, magnoval base with input grid on top cap
YH
YH1000 β Traveling-wave tube
YH1050 β Traveling-wave tube
YH1110 β Traveling-wave tube
YH1120 β Traveling-wave tube, >5Β GHz
YH1131 β Traveling-wave tube, >11Β GHz
YH1150 β Traveling-wave tube
YH1160 β Traveling-wave tube, >3Β GHz
YH1181 β Traveling-wave tube, >4Β GHz
YH1190 β Traveling-wave tube, >11Β GHz
YH1200 β Traveling-wave tube, >5Β GHz
YJ
YJ1000 β Indirectly heated, 2.5Β kW magnetron for use as a pulsed X-band oscillator between 9.19 and 9.32Β GHz
YJ1462 β Indirectly heated, 28Β kW coaxial magnetron for use as a pulsed X-band oscillator at 9.375Β GHz
YK
YK1000 β Water-cooled, permanent-magnet 11Β kW UHF linear-beam Klystron for use in TV transmitters between 400 and 620Β MHz
YK1004 β Water-cooled, permanent-magnet 11Β kW UHF linear-beam Klystron for use in TV transmitters between 610 and 790Β MHz
YK1005 β Water-cooled, permanent-magnet 11Β kW UHF linear-beam Klystron for use in TV transmitters between 470 and 860Β MHz
YK1046 β 35Β mW X-band Reflex Klystron, 9.16 to 9.34Β GHz
YK1151 β Forced-air cooled, permanent-magnet 25Β kW UHF linear-beam Klystron for use in TV transmitters between 470 and 860Β MHz
YK1190 β Water-cooled 40Β kW UHF linear-beam Klystron for use in TV transmitters between 470 and 610Β MHz
YK1191 β Water-cooled 40Β kW UHF linear-beam Klystron for use in TV transmitters between 590 and 720Β MHz
YK1192 β Water-cooled 40Β kW UHF linear-beam Klystron for use in TV transmitters between 710 and 860Β MHz
YL
YL1000/8463 β RF power pentode
YL1020/8118 β See QQZ03/20
YL1030 β See QQZ06/40
YL1050 β UHF power tetrode
YL1060/7854 β See QQE06/40
YL1070/8117 β Dual RF power tetrode
YL1071 β YL1070 with a different heater
YL1080/8348 β Dual VHF power tetrode
YL1120 β RF power tetrode
YL1130/8408 β Dual VHF power pentode
YL1150/8579 β RF beam power tetrode
YL1190/8580 β Dual UHF power tetrode
YL1200 β See PE1/100
YL1210 β QQE03/12 with a different heater
YL1220 β QQE02/5 with a different heater
YL1240/8458 β Dual VHF power tetrode
YL1250/8505 β VHF beam power tetrode
YL1270/8581 β Dual UHF power tetrode
YL1290 β QE08/200 with a different heater
YL1310/8603 β RF beam power tetrode
YL1360 β QQE04/5 with a different heater
YL1570 (RS 1084 CJ) β VHF power tetrode
Z - Gas-filled tubes
Note: See also standard M-P tubes under Z
ZA
ZA1000 β Neon-filled, coaxial, tritium-primed (half-life: 12.32 years), sputtered-molybdenum cold-cathode switching diode, meshed cylinder anode, all-glass wire-ended
ZA1001 β Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode with traces of heavy gas (krypton/xenon) for slow de-ionization, e.g. for low-frequency relaxation oscillators; meshed cylinder anode, all-glass wire-ended
ZA1002 β Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode, large difference between burning and ignition voltage, meshed cylinder anode, 3-pin all-glass wire-ended
ZA1003 β Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode for use as indicator tube in transistorized circuits, meshed cylinder anode, 3-pin all-glass wire-ended
ZA1004 β Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode, small difference between burning and ignition voltage, for use as indicator tube in transistorized circuits or as 86.4Β V Voltage reference, meshed cylinder anode, 3-pin all-glass wire-ended
ZA1005 β Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode for use like a DIAC in thyristor circuits, meshed cylinder anode, 2-pin all-glass wire-ended
ZC
ZC1010 (Z661W) β 8Β mAavg, 50Β mApeak, Gas-filled, cold-cathode AC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass wire-ended, envelope inside radioactively coated for a constant ignition voltage, for use in bidirectional counters
ZC1040 β 25Β mA, Gas-filled, cold-cathode AC trigger tetrode, one starter and a primer electrode, positive starter voltage, noval base
ZC1050 β 2Β mA, Gas-filled, cold-cathode, luminescent trigger tetrode, one starter and a primer, 300Β mlm light output for use as self-displaying shift register cells in large-format, crawling-text dot-matrix displays; all-glass wire-ended
ZC1060 β 20Β mAavg, 5Β kApeak, Gas-filled, cold-cathode, high-current trigger triode for e.g. capacitor discharge circuits. One external (capacitive) starter electrode
ZM
ZM1000 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 14Β mm character height side-viewing, left decimal point
ZM1000R β ZM1000 with a red contrast filter coating
ZM1001 β Β + - ~ Β Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1000
ZM1001R β ZM1001 with a red contrast filter coating, for use with ZM1000R
ZM1002 β Β ns ΞΌs ms s Hz kHz MHzΒ Neon-filled digital indicator tube, 13mmCH side viewing, for use with ZM1000 in digital frequency counters
ZM1003 β Β 1 - +Β Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1000
ZM1005 β Β 0 1 2 3 4 5 6 7 8 9Β Long-life neon-filled digital indicator tube, 14mmCH side-viewing, left decimal point, multiplex-capable
ZM1005R β ZM1005 with a red contrast filter coating
ZM1006 β Β 1 2 3 4 5 6Β Neon-filled digital indicator tube, side-viewing, left and right decimal point, for use in TV receivers
ZM1008 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 14mmCH side-viewing
ZM1010 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 14mmCH side-viewing, left decimal point
ZM1012 β Β 0 1 2 3 4 5 6 7 8Β Neon-filled digital indicator tube, 14mmCH side-viewing
ZM1015 β Β 0 1 2 3 4 5 6 7 8Β Neon-filled digital indicator tube, 14mmCH side-viewing
(Z520M) β ZM1022 with a red contrast filter coating
(Z521M) β ZM1023 with a red contrast filter coating, for use with ZM1020
β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH top-viewing, no decimal point
ZM1023 β Β A V Ξ© % + - ~Β Neon-filled digital indicator tube, 15.5mmCH top-viewing, for use with ZM1022 in digital multimeters
ZM1024 β ZM1025 with a red contrast filter coating, for use with ZM1020
ZM1025 β Β ΞΌs ms ns sΒ Neon-filled digital indicator tube, 15.5mmCH top-viewing, for use with ZM1022 in digital frequency counters
ZM1030 β ZM1032 with a red contrast filter coating
ZM1031 β ZM1031/01 without the Β ~Β
ZM1031/01 β ZM1033/01 with a red contrast filter coating, for use with ZM1030
ZM1032 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH side-viewing, no decimal point, 5 dual cathodes and separate odd/even anode compartments for biquinary multiplexing
ZM1033/01 β Β + - ~Β Neon-filled digital indicator tube, 15.5mmCH side-viewing, separate anode compartment for Β +Β , for use with ZM1032
(Z522M) β ZM1042 with a red contrast filter coating
ZM1041 β ZM1043 with a red contrast filter coating, for use with ZM1040
ZM1041S β ZM1043S with a red contrast filter coating, for use with ZM1040
(Z5220M) β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 30mmCH side-viewing, no decimal point
ZM1043 β Β + -Β Neon-filled digital indicator tube, 30mmCH side-viewing, for use with ZM1042
ZM1043S β Β Y X + W U Z -Β Neon-filled digital indicator tube, 30mmCH side-viewing, for use with ZM1042
ZM1047 β ZM1049 with a red contrast filter coating, for use with ZM1040
ZM1049 β Β T F S N Z Y G H M XΒ Neon-filled digital indicator tube, side-viewing, for use with ZM1042 in numerical control systems
(Z550M, 8453) β Neon-filled digital indicator tube, top-viewing, dekatron-type readout with common anode and common cathodes, pulsating anode voltage, controlled by 5-volts sensitive starter electrodes, for transistorized circuits
ZM1060 (Z505S) β Argon-filled, 50Β kHz decade Counter/Selector Dekatron
ZM1070 (Z504S, 8433) β Neon-filled, 5Β kHz decade Counter/Selector Dekatron
ZM1080 β ZM1082 with a red contrast filter coating
ZM1081 β ZM1083 with a red contrast filter coating, for use with ZM1080
ZM1082 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 14mmCH side-viewing, no decimal point, probe electrode
ZM1083 β Β + - ~Β Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1082
ZM1100 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH top-viewing
ZM1120 β ZM1122 with a red contrast filter coating
ZM1122 β Β 0 1 2 3 4 5 6 7 8 9Β Miniature neon-filled digital indicator tube, 7.8mmCH top-viewing
ZM1130 β ZM1132 with a red contrast filter coating
ZM1131 β ZM1133 with a red contrast filter coating, for use with ZM1080
ZM1132 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, side-viewing, left and right decimal point
ZM1133 β Β + - ~Β Neon-filled digital indicator tube, side-viewing, for use with ZM1132
ZM1136L/R β ZM1138L/R with a red contrast filter coating
ZM1137 β ZM1139 with a red contrast filter coating, for use with ZM1136L/R
ZM1138L/R β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 13mmCH side-viewing, left or right decimal points (specify)
ZM1139 β Β + - ~ Ω Neon-filled digital indicator tube, 13mmCH side-viewing, for use with ZM1138 in digital multimeters
ZM1162 β Β 0 1 2 3 4 5 6 7 8 9Β Long-life neon-filled digital indicator tube, 15.5mmCH top-viewing, no decimal point, rectangular envelope for close stacking in both axes
ZM1170 β ZM1172 with a red contrast filter coating
ZM1172 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH side-viewing, no decimal point
ZM1174 β ZM1175 with a red contrast filter coating
ZM1175 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH side-viewing, left decimal point
ZM1176 β ZM1177 with a red contrast filter coating
ZM1177 β ZM1175, but right decimal point
ZM1180 β ZM1182 with a red contrast filter coating
ZM1181 β ZM1183 with a red contrast filter coating, for use with ZM1180
ZM1182 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 16mmCH top-viewing, no decimal point, semi-rectangular envelope for close horizontal stacking
ZM1183 β Β + - ~ Ω Neon-filled digital indicator tube, top-viewing, 13mmCH for use with ZM1182 in digital multimeters
ZM1184D β ZM1185D with a red contrast filter coating
ZM1185A (GR1420) β Β 1 2 3 4 5 6 U K E RΒ Neon-filled digital indicator tube, 16mmCH top-viewing
ZM1185D (GR1430) β Β β ΞΒ Neon-filled digital indicator tube, 16mmCH top-viewing, for use in elevators
ZM1185E (GR1472) β Β 0 1 2 3 4 5 - t kg +Β Neon-filled digital indicator tube, 16mmCH top-viewing
ZM1200 β Pandicon, multiplexed 14-digit display tube with decimal points and punctuation marks, pin connections on both ends
ZM1202 β 12-Digit Pandicon
ZM1204 β 10-Digit Pandicon
ZM1206 β 8-Digit Pandicon
ZM1210 β ZM1212 with a red contrast filter coating
ZM1212 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH side-viewing, left decimal point, all-glass wire-ended
ZM1220 β ZM1222 with a red contrast filter coating
ZM1222 β Β 0 1 2 3 4 5 6 7 8 9Β Large neon-filled digital indicator tube, 40mmCH side-viewing
ZM1230 β ZM1232 with a red contrast filter coating
ZM1232 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 15.5mmCH upside-down side-viewing, no decimal point
ZM1240 β ZM1242 with a red contrast filter coating
ZM1241 β ZM1243 with a red contrast filter coating, for use with ZM1240
ZM1242 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 16mmCH side-viewing, right decimal point
ZM1243 β Β + - ~ Ω Neon-filled digital indicator tube, 16mmCH side-viewing, for use with ZM1242 in digital multimeters
ZM1263 β Β ~ + - β«Β Neon-filled digital indicator tube, 10mmCH side-viewing
ZM1290 β ZM1292 with a red contrast filter coating
ZM1292 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 10mmCH side-viewing
ZM1330 β ZM1332 with a red contrast filter coating
ZM1331 β ZM1333 with a red contrast filter coating, for use with ZM1330
ZM1332 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 13.1mmCH side-viewing, left and right decimal points, all-glass wire-ended
ZM1333 β Β + - ~ Ω Neon-filled digital indicator tube, 13.1mmCH side-viewing, all-glass wire-ended, for use with ZM1332 in digital multimeters
ZM1334 β ZM1336 with a red contrast filter coating
ZM1335 β ZM1337 with a red contrast filter coating, for use with ZM1334
ZM1336 β Β 0 1 2 3 4 5 6 7 8 9Β Neon-filled digital indicator tube, 13.1mmCH side-viewing, left and right decimal points, multiplex-capable
ZM1337 β Β + - ~ Ω Neon-filled digital indicator tube, 13.0mmCH side-viewing, right decimal point (!), all-glass wire-ended, red contrast filter coating, for use with ZM1336 in digital multimeters
ZM1350 β Varisymbol, planar neon-filled digital 40mm x 27mm fourteen-segment display tube, right decimal point, separate underscore text cursor, keep-alive cathode, multiplex-capable, viewing angle 160Β°
ZM1360 β ZM1350 with 60mm x 40mm characters
ZM1370 β ZM1350 with 20mm x 13mm characters
ZM1410 β ZM1412 with a red contrast filter coating
ZM1412 β Neon-filled digital seven-segment display tube, 8.6mmCH side-viewing, right decimal point and left punctuation mark, all-glass wire-ended
ZM1500 β Pandicon, multiplexed 12-digit, 7-segment display tube
ZM1550 β Planar neon-filled digital two-digit seven-segment display tube, right decimal points
ZM1551 β Planar neon-filled digital -digit seven-segment display tube with Β +Β and Β -Β signs, right decimal points
Note: More Nixie tubes under standard - ZM and ETL examples
ZP
ZP1000 β Boron trifluoride-filled Geiger-MΓΌller tube, thermal neutrons
ZP1010 β Boron trifluoride-filled Geiger-MΓΌller tube, thermal neutrons
ZP1020 β Boron trifluoride-filled Geiger-MΓΌller tube, thermal neutrons
ZP1070 β Subminiature Geiger-MΓΌller tube, all-glass wire-ended
ZP1080 β Halogen-quenched Geiger-MΓΌller tube, Ξ² and Ξ³
ZP1100 β Halogen-quenched Geiger-MΓΌller tube, Ξ³; wire-ended
ZP1200 β Halogen-quenched Geiger-MΓΌller tube, Ξ³
ZP1300 β Halogen-quenched Geiger-MΓΌller tube, Ξ³ and high-energy Ξ²
ZP1330 β Halogen-quenched Geiger-MΓΌller tube, for use in damp and/or saline atmosphere, Ξ² and Ξ³
ZP1400 β Halogen-quenched Geiger-MΓΌller tube, 9mm diameter mica window, Ξ² and Ξ³
ZP1430 β Halogen-quenched Geiger-MΓΌller tube, 27.8mm diameter mica window, Ξ±, Ξ², Ξ³
ZP1490 β Halogen-quenched Geiger-MΓΌller tube, 28mm diameter mica window, low-level Ξ±, Ξ² and Ξ³
ZP1600 β Halogen-quenched Geiger-MΓΌller tube, 19.8Β mm diameter mica window, X-rays, 6.0 to 20Β keV energy, 60 to 200Β pm wavelength range
ZP1610 β Side window, organically quenched Geiger-MΓΌller tube. 7 x 18Β mm mica window; X-rays, 2.5 to 40Β keV energy, 30 to 500Β pm wavelength range
ZP1700 β Halogen-quenched, cosmic-ray guard counter tube for low-background measurements; to be used with another radiation counter tube in an anticoincidence circuit
ZP1800 β Halogen-quenched Geiger-MΓΌller tube for use at temperatures up to 200Β Β°C, Ξ³
ZP1810 β Halogen-quenched Geiger-MΓΌller tube for use at temperatures up to 200Β Β°C, Ξ³, low sensitivity, up to 40 mGy/h
ZP1860 β Halogen-quenched Geiger-MΓΌller tube, Ξ² and Ξ³
ZT
ZT1000 β 21Β kV, 10Β A Mercury vapor triode thyratron
ZX
ZX1000 β 800Β V, 1140Β Apk, 13Aavg Ignitron
ZX1051 β Water-cooled, 56Β Aavg Ignitron
ZX1052 β Water-cooled, 140Β Aavg Ignitron
ZX1053 β Water-cooled, 355Β Aavg Ignitron
ZX1060 β Water-cooled, 10Β Aavg Ignitron
ZX1061 β Water-cooled, 10Β Aavg Ignitron
ZX1062 β Water-cooled, 10Β Aavg Ignitron
ZX1063 β Water-cooled, 10Β Aavg Ignitron
ZY
ZY1000 (872B) β High voltage, half-wave mercury-vapor rectifier
ZY1001/8008A β High voltage, half-wave mercury-vapor rectifier, 4-pin base with anode top cap
ZY1002 β High voltage, half-wave mercury-vapor rectifier, E40 (Goliath) Edison screw lamp base with anode top cap
ZZ
ZZ1000 β 81Β V Voltage reference, 2-pin all-glass wire-ended
ZZ1010 β 85Β V Voltage reference
ZZ1020 (STV85-8) β 82Β V Voltage reference with primer electrode, 3-pin all-glass wire-ended
ZZ1030 (STV500-0,1) β Quad 125Β V Voltage references, noval base
ZZ1031 β Quad Voltage reference, noval base
ZZ1040 (STV100-60Z) β 100Β V Voltage reference with primer electrode
ZZ1050 β 82Β V Voltage reference, 2-pin all-glass wire-ended
List of European transmitting tubes
Note: Typecode explained above.
B - Backward-wave amplifier
BA
BA9/20 β X-band, 20Β mW, Forced-air cooled backward-wave oscillator
D - Rectifier incl. grid-controlled
DA
DA1.5/75 β 1.5Β kV, 75Β W Half-wave power rectifier, triode TA1.5/75 without grid
DA12/24000 β 12Β kV, 24Β kW Water-cooled half-wave power rectifier
DC
DC1/50 β 1Β kV, 75Β mA Full-wave power rectifier, DC1/60 with dual anode top cap
DC1/60 β DC1/50 with heater and dual anode on 4-pin base
DC2/200 β 2Β kV, 100Β mA Full-wave power rectifier with dual anode top cap
DCG
DCG1/125 β 1Β kV, 125Β mA Half-wave mercury-vapor rectifier with Edison screw lamp base and anode top cap
DCG12/30 β 12Β kV, 2.5Β A Grid-controlled, half-wave mercury-vapor rectifier with anode top cap
DCX
DCX4/1000 β 4Β kV, 1Β kW Half-wave xenon rectifier with anode top cap
DCX4/5000 β 4Β kV, 5Β kW Half-wave xenon rectifier with anode top cap
DE
DE2/200 β 2Β kV, 100Β W Full-wave power rectifier with dual anode top cap
J - Magnetron
JP
JP8/02B β 8.8Β GHz, 25Β W Magnetron
JP9/15 β 9.345 to 9.405Β GHz, 15Β kW Forced-air cooled magnetron for pulsed service
JPT
JPT9/01 β 9.15 to 9.60Β GHz, 5Β W Magnetron
K - Klystron
KB
KB9/150W β X-band, 150Β W Water-cooled, dual-resonator klystron
KS
KS7/85 β 6.5 to 7.5Β GHz, 85Β mW Reflex klystron
L - Traveling-wave tube
LA
LA9/3 β 7 to 11.5Β GHz Forward-wave amplifier
LA16/2 β 11.5 to 18Β GHz Forward-wave amplifier
M - AF modulator Triode
MA
MA4/600 β 4Β kV, 600Β W Radiation-cooled triode
MB
MB1/50 β 1Β kV, 50Β W Radiation-cooled triode
MB2/200 β 2Β kV, 200Β W Radiation-cooled triode
MY
MY3/275 β 3Β kV, 275Β W Radiation-cooled triode
MZ
MZ2/200 β 2Β kV, 200Β W Radiation-cooled triode
P - Pentode
PA
PA12/15 β 15Β kW Water-cooled shortwave pentode
PA12/20 β 20Β kW Water-cooled pentode made by Philips and used in the 1930s and 1940s
PAL
PAL12/15 β Air-cooled version of PAW12/15
PAW
PAW12/15 β 15Β kW Water-cooled shortwave pentode
PB
PB2/200 β 200Β W Shortwave pentode
PB3/1000 β 1Β kW Shortwave pentode
PC
PC03/3 β 3Β W Shortwave pentode
PC3/1000 β 1Β kW Shortwave pentode
PE
PE04/10 β 10Β W Shortwave pentode
(YL1200) β 100Β W Shortwave pentode
Q - Tetrode
QB
QB2/75 β 75Β W Beam-tetrode
QB5/2000 β 2Β kW Beam-tetrode
QBL
QBL4/800 β Air-cooled 800Β W beam-tetrode
QBL5/3500 β Air-cooled 3500Β W beam-tetrode
QBW
QBW5/3500 β Water-cooled 3500Β W beam-tetrode
QC
QC05/15 β 15Β W Beam-tetrode
QC05/35 β 35Β W Beam-tetrode
QE
QE04/10 β 10Β W Beam-tetrode
QE05/40 (6146) β 40Β W Radiation-cooled output beam-tetrode, popular amongst radio amateurs as a final RF amplifier
β 200Β W Beam-tetrode
QEL
QEL1/150 β Air-cooled 150Β W beam-tetrode
QEL1/250 β Air-cooled 250Β W beam-tetrode
QEP
QEP20/18 β 18Β W Beam-tetrode for use as a pulse modulator
QQC
QQC03/14 β 14Β W Dual beam-tetrode
QQE
(6939) β 5Β W Dual beam-tetrode
(6360) β 12Β W Dual beam-tetrode
QQE03/20 (6252) β 20Β W Dual beam-tetrode
(7377) β 5Β W Dual beam-tetrode
(5894, YL1060) β 40Β W dual beam-tetrode, internally neutralized, Septar base with dual anode top cap
QQV
QQV02/6 β 6Β W dual beam-tetrode
QQV03/20A β 20Β W Radiation-cooled split-anode tetrode made by Mullard and used in the 1940s, 1950s and 1960s as a VHF frequency-doubling output stage with balanced output.
QQV07/50 β 50Β W Dual beam-tetrode
QQZ
(8118, YL1020) β 20Β W Dual beam-tetrode
(YL1030) β 40Β W Dual beam-tetrode
QV
QV04/7 β 7Β W Beam-tetrode
QV05/25 (807) β 25Β W Radiation-cooled output beam-tetrode made by Mullard.
QV2/250C β 250Β W Beam-tetrode
QY
QY3/65 β 65Β W Beam-tetrode
QY5/3000A β 3Β kW Beam-tetrode
QY5/3000W β Water-cooled version of QY5-3000A
QYS
QYS50/P40 β Pulsed power tetrode, Silica envelope, 50Β kV anode voltage, considerable x-radiation, 810Β Β°C anode temperature at 700Β W anode dissipation, 40Β A anode current at duty factor 0.0005, Vg1Cut-offΒ (IA=1Β mA@VA=55Β kV):Β >Β -3.4Β kV, gm:Β 38Β mS
QZ
QZ06/20 β 25Β W VHF Power tetrode up to 175Β MHz
R - Rectifier incl. grid-controlled
RG
RG1000/3000 β 1Β kV, 3Β A Half-wave mercury-vapor rectifier with anode top cap
RGQ
RGQ7.5/0.6, RSQ7.5/0.6 (Grid-controlled) β 7.5Β kV, 600Β mA Half-wave mercury-vapor rectifier with anode top cap
RGQ20/5, RSQ15/40 (Grid-controlled) β 20Β kV, 5Β A Half-wave mercury-vapor rectifier with anode top cap
T - RF amplifier/oscillator Triode
TA
TA04/5 β 400Β V, 50Β W Radiation-cooled power triode
TA1.5/75 β 1.5Β kV, 75Β W Radiation-cooled power triode
TA4/2000K β 4Β kV, 2Β kW Air-cooled power triode made by Philips in the 1930s
TA18/100000 β 18Β kV, 100Β kW Water-cooled power triode
TB
TB04/8 β Directly heated Doorknob VHF power triode up to 600Β MHz
TB2.5/400 β 2.5Β kV, 300Β W Radiation-cooled power triode
TB5/2500 β 5Β kV, 2.5Β kW Radiation-cooled power triode
TBL
TBL2/300 β 2Β kV, 300Β W Forced air-cooled power triode
TBL15/125 β 15Β kV, 125Β kW Forced air-cooled power triode, 3-phase filament structure
TBW
TBW6/14 β 6Β kV, 14Β kW Water-cooled power triode
TBW15/125 β 15Β kV, 125Β kW Water-cooled power triode, 3-phase filament structure
TC
TC03/5 β RF power triode up to 85Β MHz, 5Β W
TC2/250 β RF power triode up to 20Β MHz, 250Β W
TD
TD03/5 β Indirectly heated disk-seal UHF power triode up to 2Β GHz
TD03/10 β Indirectly heated disk-seal UHF power triode up to 2.8Β W, 3.75Β GHz
TD03/10F β TD03/10 with internal feedback for use as an oscillator
TD04/20 β Indirectly heated disk-seal UHF power triode up to 13.5Β W, 1Β GHz
TD1/100C = 2C39BA β Indirectly heated, ceramic disk-seal UHF power triode up to 24Β W, 3.5Β GHz
TD2/400 β Directly heated, ceramic disk-seal UHF power triode up to 600Β W, 900Β MHz
TD2/500 β Directly heated, ceramic disk-seal UHF power triode up to 500Β W, 940Β MHz
TE
TE05/10 β RF power triode up to 150Β MHz
TX
TX12/12W β Water-cooled RF power triode
TX12/20W β Water-cooled RF power triode
TX10/4000 β Power triode, Silica envelope, 12Β kV anode voltage, 4Β kW anode dissipation, 1.6Β A cathode current, gm:Β 4.5Β mS, for use as self-excited high-power oscillator in induction heating equipment.
TY
TY2/125 β 135Β W VHF power triode up to 200Β MHz
TY12/50A β Forced-air cooled 45Β kW RF power triode up to 30Β MHz
TY12/50W β Water-cooled 50Β kW RF power triode up to 30Β MHz
TYS
TYS2/250 β Power triode, Silica envelope, 2.5Β kV anode voltage, 250Β W anode dissipation
TYS4/500 β Power triode, Silica envelope
TYS5/1000 β Power triode, Silica envelope
TYS5/2000 β Power triode, Silica envelope
TYS5/3000 β Power triode, Silica envelope, 6Β kV anode voltage, 950Β Β°C anode temperature at 3.5Β kW anode dissipation, 2.8Β A cathode current, gm:Β 15Β mS. Used in RF generators for induction hardening.
X - Thyratron
XGQ
XGQ2/6400 β 2Β kV, 6.4Β kW Mercury-vapor tetrode thyratron with anode and grid1 top caps
XR
XR1/1600 (5545) β 1Β kV, 1.6Β kW Inert gas-filled triode thyratron with anode top cap
XR1/6400 β 1Β kV, 6.4Β kW Inert gas-filled triode thyratron with anode top cap
Compagnie des Lampes (1921, "French Mazda") and Mazda-Belvu
Not to be confused with Compagnie des Lampes (1888, see above) nor with British Mazda (see above).
The 1921 incarnation of La Compagnie des Lampes (since 1953 as Lampe Mazda) made light bulbs and electronic tubes under the French Mazda brand. Many of their tubes were also available from Compagnie Industrielle FranΓ§aise des Tubes Electroniques (CIFTE) under their Mazda-Belvu brand, which otherwise used mostly EIA, RETMA and MullardβPhilips tube designations.
Examples:
Before 1949:
1883 β Indirectly heated, 350Β V/125Β mA full-wave rectifier, 5Β V/1.6Β A heater
2XM600 β Directly heated, 10Β kV/250Β mA half-wave mercury-vapor rectifier, 2.5Β V/5Β A heater
4Y25 = 807 β Indirectly heated beam tetrode
RETMA tube 6H8G
RCA-800 tubes 879, 884
Since 1949 with a fire pot logo:
RMA tube 2E30
3T20 β Directly heated power triode, graphite anode
3T100 β Directly heated power triode, graphite anode
4Y50 β Indirectly heated beam tetrode
E1 β Electrometer tetrode
E2 β Dual electrometer tetrode
ST130 β 130Β V Neon-filled voltage reference
Since 1953 as LAMPE MAZDA:
RMA tube 2G21
4Y100 = 7745 β Dual beam tetrode
RCA-800 tubes 829, 832
927 β Gas-filled phototube
929 β Vacuum phototube
EIA tubes 6196, 6250
E5 β Subminiature electrometer tetrode, all-glass wire-ended
Since 1959 with a Faravahar logo related to Ahura Mazda:
3T50 β Directly heated power triode, thoriated-tungsten filament, graphite anode
4Y75 β Directly heated power triode
6P9 = 6BM5 β Power pentode, Miniature 7-pin base
RETMA tube 6K8
78A β Directly heated, educational diode
EIA tubes 7233, 7242, 7377, 8418
E6 β Subminiature dual electrometer tetrode, all-glass wire-ended
E7, E9 β Subminiature electrometer pentodes, all-glass wire-ended
MullardβPhilips tubes ECF202, ECL802, ED501, EF816, EL503, EY81F, EY802, GY86, GY802, PY81F
F7024A (Diode), F7024C (Triode), F7024E (Tetrode), F7024L (Pentode) β Set of 4 educational tubes
F9116 β Electrometer tetrode
K25000A1 β Directly heated, 25Β kV/70Β mA half-wave rectifier, 2.5Β V/9Β A heater
List of Russian tubes
Standard tubes
Note: Typecode explained above.
6J1J 6Π1Π (954) β Indirectly heated Acorn-type sharp-cutoff pentode, 6.3Β V heater
6K1J 6Π1Π (956) β Indirectly heated Acorn-type remote-cutoff pentode, 6.3Β V heater
6L1P 6Π1Π β Nonode for FM quadrature detection
6N1P 6Π1Π β Dual triode, similar to 6DJ8/ECC88
6N2P 6Π2Π β Dual triode, similar to 12AX7/ECC83
6N3P 6Π3Π (2C51) β Dual triode
6N8S 6Π8Π‘ (6SN7/ECC32) β Dual triode
6N9S 6Π9Π‘ (6SL7) β Dual triode
6N13S 6Π13Π‘ (6AS7G) β Dual power triode
6N14P 6Π14Π β Dual RF/VHF triode, similar to ECC84/6CW7
6N23P 6Π23Π (6DJ8/ECC88) β Dual triode
6N24P 6Π24Π (ECC89/6FC7, 6ES8) β Dual RF/VHF triode for cascode amps
6P1P 6Π1Π β Power pentode, similar to 6AQ5/EL90
6P3S 6Π3Π‘ β Beam-power tetrode, similar to 6L6GB
6P3S-E 6Π3Π‘-Π β Beam-power tetrode, similar to 5881/6L6WGB
6P6S 6Π6Π‘ (6V6) β Beam-power tetrode
6P14P 6Π14Π (6BQ5/EL84) β Power pentode
6P41S 6Π41Π‘ β Beam power tetrode, designed for TV sets, used in line output stages, similar to 7868.
6P45S 6Π45Π‘ (6KG6/EL509) β Beam power tetrode, designed for TV sets, used in line output stages.
6S1J 6Π‘1Π (955) β Indirectly heated Acorn-type triode, 6.3Β V heater
6S19P 6Π‘19Π β Output triode
Professional tubes
Note: Typecode explained above.
V1-0.15/55 Π1-0.15/55 β 55Β kV, 150Β mA Half-wave rectifier
VI1-5/20 ΠΠ1-5/20 β 20Β kV, 5Β A Half-wave pulse rectifier
G-807 Π-807 β Shortwave transmitter tube (the Russian 807 analogue).
GI-7B ΠΠ-7Π β Impulse tube
GM-70 ΠΠ-70 β Modulator tube
GK-71 ΠΠ-71 - RF generation and power amplification, 125 watt pentode, direct heating.
GS-31B ΠΠ‘-31Π β UHF transmitter tube
GU-29 ΠΠ£-29 β VHF transmitter tube, dual beam tetrode, 20W max. anode dissipation per section.
GU-32 ΠΠ£-32 β VHF transmitter tube, dual beam tetrode, 15W max. anode dissipation per section.
GU-50 ΠΠ£-50 β VHF transmitter pentode, similar to the German LS-50 (no direct U.S. equivalent)
GU-78B ΠΠ£-78Π β VHF transmitter tetrode
GU-81M ΠΠ£-81M β RF generation and power amplification, 450 watt pentode, direct heating.
I3-70-0.8A Π3-70-0.8 β 800Β V, 70Β A Ignitron
I3-200-1.5A Π3-200-1.5 β 1.5Β kV, 200Β A Ignitron
LP-4 ΠΠ-4 β Linear trochotron, 26-pin Acorn-type all-glass wire-ended,
SG203K Π‘Π203Π β 82Β V Voltage reference
SG204K Π‘Π204Π β 164Β V Voltage reference
TGI1-270/12 Π’ΠΠ1-270/12 β 12Β kV, 270Β A Hydrogen thyratron
Indicator tubes
IN-33 ΠΠ-33 β Neon-filled, planar, dual 105-segment linear glow-transfer plasma bar graph display with three cathode strings, for use in VUΒ meters etc.; similar to BG16101
ITM2-M ΠΠ’Π2-Π β Four-color phosphored-thyratron latching pixel; 4x4 array of 4 subminiature dual-starter luminescent thyratrons each for the colors red, yellow, green and blue (thus, 5 intensities per color yields 54 = 625 colors), 4x4 matrix of 10-volts sensitive starter electrodes, cubic envelope for easy stacking in both axes, 12-pin all-glass wire-ended, similar to today's RGBA LEDs
ITS1 ΠΠ’Π‘1 β Green phosphored-thyratron latching seven-segment display, no decimal point, 5-volts sensitive starter electrodes, all-glass wire-ended, rectangular envelope for easy stacking in both axes
MTX-90 ΠΠ’Π₯-90 β Small neon-filled thyratron for use as a latching single-dot indicator, top-viewing, top of envelope acts as a magnifier, all-glass wire-ended, comes with a blob of solder on the end of each wire for rapid installing, like today's ball grid arrays
List of other number tubes
1
175HQ β Ultra high reliability pentode for use in long-haul submarine communications cable repeaters
1600s
1602 β Directly heated power triode used for A.F. amplification with low microphonics. 7.5 volt filament. 12 watts of A.F. operating in Class-A. 15 watts of low R.F. operating in Class-C. Similar to type 10.
1603 β Indirectly heated pentode used for A.F. amplification with low microphonics. Similar to types 6U7, 57, 6D6 and 6C6. UX6 Base.
1608 β Directly heated triode giving 20 watts at up to 45Β MHz. 2.5 volt heater/filament. UX base.
1609 β Directly heated pentode used for A.F. amplification with low microphonics. American 5-Pin(UY)base.
1610 β Directly heated pentode specially designed for use as a crystal oscillator. 2.5 volt heater/filament, American 5-Pin base.
1612 β Pentagrid converter; low-microphonics version of type 6L7. Both control grids (1 and 3) are sharp-cutoff.
1619 β Beam Power Tetrode, similar to 6L6 with directly heated filament, common in World War II battle tank transmitters.
1624, 1625 β Very similar to the 807, but with different heater voltage
1626 β RF triode, very similar to 6J5 but with 12.6 volt filament
1629 β Tuning indicator tube with DC amplifier triode unit
1630 β Indirectly heated, orbital-beam, secondary-emission, 12-pin Jumbo Acorn-type UHF hexode
1633 β Dual triode, equivalent to 6SN7 with 25 volt heater (World War II aircraft use)
1635 β Indirectly heated, 2Γ3Β W dual AF power triode, Octal base
1636 β Secondary emission UHF beam deflection tube, used as a balanced mixer up to 600Β MHz
1650 β High-altitude version of the 955 Acorn-type triode
1680 β Dual-control heptode for use as a NAND gate in a coincidence circuit in IBM computers, 6BE6/EK90 with a sharp-cutoff grid no.3
2
24B1 β Trigatron
24B9 β Trigatron
29C1 β Directly heated saturated-emission diode; acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits.
200s
203A β 100Β W, Directly heated RF transmitter power triode, 4-pin base, anode on top cap
204A β 250Β W, Directly heated RF transmitter power triode, 3-pin base, anode on top cap
205D β 14Β W, Directly heated AF or modulator power triode, 4-pin base
207 β 10Β kW, Water-cooled, directly heated RF transmitter power triode
210T β Directly heated RF transmitter power triode, 4-pin base, similar to type 10 triode with an isolantite base
210DET β Cossor directly heated, 2 volts, special detector
210HF β Cossor, directly heated, 2 volts, triode
210HL β Cossor, directly heated, 2 volts, triode
210LF β Cossor, directly heated, 2 volts, triode
210PG β Cossor, directly heated, 2 volts, variable-mu pentagrid
210RC β Cossor, directly heated, 2 volts, very high impedance triode
210SPT β Cossor, directly heated, 2 volts, HF pentode
210VPT β Cossor, directly heated, 2 volts, HF variable-mu shielded pentode
211 β 260Β W, Directly heated AF or modulator power triode now favored by audiophiles; Jumbo 4-pin base
212E β 275Β W, Directly heated RF transmitter power triode, 4-pin base
215P β Cossor, directly heated AF power triode
220B β 10Β kW, Water-cooled, directly heated AF/modulator power triode
228A β 5Β kW, Directly heated RF/AF power triode
230XP β Cossor, directly heated power triode
232C β 25Β kW, Water-cooled, directly heated RF transmitter power triode
236A β 20Β kW, Water-cooled, directly heated RF transmitter power triode
240B β Cossor, directly heated dual AF power triode
241B β 275Β W, Directly heated AF/modulator power triode, 3-pin base, anode on top cap
242A β Directly heated AF/modulator power triode, 4-pin base
250TH β 1.1Β kW, Directly heated AF/modulator power triode, 4-pin base, anode on top cap
254A β 20Β W, Directly heated RF transmitter power triode, 4-pin base, anode on top cap
261A β 125Β W, Directly heated AF/modulator power triode, 4-pin base
268A β 25Β W, Directly heated power triode, 4-pin base, anode on top cap
270A β 350Β W, Directly heated AF/RF power triode, 4-pin base, anode on top cap
275A β 17Β W, Directly heated AF power triode, 4-pin base
276A β 125Β W, Directly heated AF/RF power triode, 4-pin base
279A β 1.2Β kW, Directly heated AF/RF power triode
295A β 100Β W, Directly heated AF/RF power triode, 4-pin base
298A β 100Β kW, Water-cooled, directly heated power triode
3
300s
300B β 40Β watt directly heated power triode, 4-pin base
316A = VT191 β Directly heated Doorknob-type UHF power triode up to 750Β MHz
322 β Oil can-type disk-seal UHF clipper power diode, 800Β VPIV, 15Β W, 1500Β MHz
328 β Tungar bulb, a low-voltage, gas-filled, full wave rectifier for charging 12V lead-acid batteries at 1.3Β A
368A β Directly heated Doorknob UHF power triode, graphite anode, up to 1.7Β GHz
388A β Directly heated Doorknob UHF power triode, graphite anode, up to 1.7Β GHz
4
4XP β Cossor, directly heated power triode
41MP β Cossor, indirectly heated power triode
400s
402P β Cossor, indirectly heated power triode, 7-pin base
416B β Planar SHF power triode, 500Β mW output at 4Β GHz
416D β Planar SHF power triode with BeO spacers, 5Β W output at 4Β GHz
446A β Early Lighthouse UHF triode, 10Β dB noise figure at 1Β GHz
450TH β Early Eimac high-mu power triode, 450 watt anode dissipation to 40Β MHz
455A β Ultra high reliability pentode for use in submarine communications cable repeaters
4000s
Philips:
4065 β Directly heated electrometer triode, grid current β€125Β fA, 4-pin all-glass wire-end, for probe amplifiers
4613 β Directly heated power triode, 4-pin base
4614 β Indirectly heated power triode, 5-pin base
4641 β Directly heated power triode, 4-pin base
4671/E1C (955) β Indirectly heated Acorn triode
4672/E1F (954) β Indirectly heated Acorn pentode
4674 β Indirectly heated Acorn diode
4675 β 4671/E1C with a 4Β Volts heater
4676 β 4672/E1F with a 4Β Volts heater
4678 (EM1) β Indirectly heated tuning indicator
4683 β Directly heated power triode, side-contact 8 base
4695/E2F (956) β Indirectly heated Acorn pentode
RCA:
4042 β Ceramic/metal pencil-type disk-seal UHF power triode for pulsed operation up to 425Β W
4062A β Ceramic/metal pencil-type disk-seal SHF power triode up to 4Β GHz, mu = 100, Panode = 10Β W
4560 β Character generator monoscope for text mode video rendering in early computer monitors, with a square target having letters, digits and symbols stenciled into it in a customer-supplied 8x8 array. An electron beam selects and scans a character, both by appropriate electrostatic deflection, and generates an analog video signal; cf. CK1414, TH9503
4598, 7539, 7828, 8087, 8098 β Graphechon dual-electron gun scan conversion tubes, analog video transcoders with simultaneous R/W capability for realtime resolution and frame rate transcoding between different analog video standards. This was achieved by a CRT/camera tube combination; the CRT part writes onto a thin, dielectric target; the camera part reads the generated charge pattern at a different scan rate from the back side of this target. The setup could also be used as a genlock
Standard Telephones and Cables:
4205E = 205E β Directly heated power triode, 4-pin bayonet base with offset pin
4270A = 270A = 3C/350E β Directly heated power triode, 3-pin base
4275A = 275A β Directly heated power triode, 4-pin base
4300A = 300A β Directly heated power triode, 4-pin base
4307A = 307A β Power pentode similar to the output beam-tetrode type 807. It differs from an 807 by being a directly heated pentode rather than an indirectly heated beam-tetrode. Both types are contained in an ST-16 bulb with an anode cap and 5-pin "American" UY base
The SY4307A is historically notable because a pair of them in parallel Class-C was used as the output stage in a transmitter built in secret by Australian soldiers in Japanese-occupied Portuguese Timor during World War II in 1942. This transmitter, now reconstructed and on display at the Australian War Memorial in Canberra, was called "Winnie the War Winner".
4307AF β 4307A qualified for use in standard aircraft radio
5
5BP4 β Five-inch CRT used in pre-World War II television receivers, such as the RCA TRK-5 and in early radars such as the SCR-268 and SCR-270.
5CEP11 (blue, short persistence); 10VP15, 5AKP15, 5DKP15, 5ZP15 (blue-green, extremely short); 5BNP16, 5CEP16, 5DKP16, 5ZP16 (violet/near-ultraviolet, very short); 5AKP24, 5AUP24, 5DKP24, 5ZP24 (green, short); 131QP55 (blue-green, very short); 131QP56 (blue-violet, very short) β CRT-type flying-spot scanners for use in a telecine
500s
527 β High-mu power triode up to 900Β W
559 β Lighthouse-type disk-seal UHF diode
592 = 3-200A3 β Medium-mu power triode up to 200Β W, 150Β MHz
6
6P10 β Ultra high reliability pentode for use in short-haul submarine communications cable repeaters
6P12 β Ultra high reliability pentode for use in long-haul submarine communications cable repeaters
7
7JP1 β Monochrome cathode ray tube for use in early postwar oscilloscopes. Electrostatic deflection, P1 green, short-persistence phosphor, screen.
7JP4 β Monochrome cathode ray tube common in early postwar TV receivers. Electrostatic deflection, P4 white, medium-persistence phosphor, screen.
7JP7 β Monochrome cathode ray tube for use in early postwar radar displays. Electrostatic deflection, P7 blue-white, long-persistence phosphor, screen.
700s
703A β Directly heated Doorknob UHF power triode up to 1.5Β GHz
713A β Indirectly heated Little Doorknob UHF pentode, Bakelite Octal base
717A (CV3594, VT269) β 713A with a metal shield and a low loss mica-filled phenolic resin Octal base
8
800s
800 β Directly heated V.H.F. power triode, giving 35Β watts up to 60Β MHz and 18Β watts at 180Β MHz. American 4-Pin(UX)base with side locating pin.
801 β Directly heated power triode, used in pairs in Class-B in A.M. modulation sections of transmitters giving up to 45 watts of power at 60Β MHz and 22 watts at 120Β MHz.
802 β Indirectly heated H.F. power pentode, giving 8 watts up to 30Β MHz and 4 watts at 110Β MHz.
803 β Directly heated H.F. power pentode, giving 50 watts up to 20Β MHz and 25 watts at 70Β MHz.
804 β Directly heated H.F. power pentode, giving 20 watts up to 15Β MHz and 10 watts at 10Β MHz.
805 β Directly heated H.F. high-mu triode, giving 140 watts up to 30Β MHz and 70 watts at 85Β MHz.
806 β Directly heated H.F. high-mu triode, giving 390 watts up to 30Β MHz 195 watts at 100Β MHz.
807 β Indirectly heated H.F. beam power tetrode, giving 25 watts up to 30Β MHz and 12 watts at 125Β MHz. A variation of type 6L6 originally designed as a Class-C transmitter tube. Later used in pairs as push-pull outputs for high-wattage Class-AB2 audio amplifiers. Also used as a horizontal output tube in early TV receivers. One of the first commercial tubes that used the top cap to connect the anode (instead of the control grid) to the circuit.
808 β Directly heated H.F. high-mu triode, giving 140 watts up to 30Β MHz and 70 watts at 130Β MHz.
809 β Directly heated H.F. high-mu triode, giving 55 watts up to 27Β MHz and 30 watts at 100Β MHz.
810 β Directly heated H.F. triode, 10 volt filament and Zirconium Carbide anode. Base fits R.C.A. UT-541A Socket.
811A β Directly heated H.F. triode, 6.3 volt filament, 88 watts
813 β Beam Power Tetrode possessing about 5 times the Anode dissipation of an 807.
814 β A directly heated Beam Power Tetrode giving about 130 watts at 30Β MHz and 65 watts at 100Β MHz operating in Class-C.
815 β An indirectly heated dual beam power pentode. Octal base.
825 β First commercially available klystrode, a VHF/UHF linear-beam transmitting tube, similar to a klystron
829 β A dual indirectly heated beam power tetrode. Two 6.3 volt heaters sharing a common tap.
830 β A directly heated triode giving about 50 watts at 15Β MHz and 7.5 watts at 60Β MHz operating in Class-C.
831 β A directly heated triode giving about 400 watts at 20Β MHz and 200 watts at 60Β MHz operating in Class-C. 11 volt heater/filament.
833 β A larger directly heated high-mu triode giving about 1Β kW at 30Β MHz and 500 watts at 45Β MHz operating in Class-C. Usable up to 100Β MHz at reduced power, (400Β W). 10Β volt heater/filament drawing 10Β A. The anode of this device is fabricated from tantalum. Anode current of 800Β mA with an anode voltage of 3Β kV and grid voltage of zero. Anode current of 4.3Β A at a voltage of 750 with 350 volt on the grid. Uses two-part R.C.A socket assembly UT-103.
833A β Improved 833.
834 β A directly heated triode giving 58 watts at 100Β MHz and 25 watts at 350Β MHz operating in Class-C. 7.5 volt heater/filament. Fitted with an American 4-Pin, (UX4), base with side locating pin.
836 β An indirectly heated high vacuum rectifier with a peak inverse voltage of 5Β kV and peak anode current of 1 ampere. 2.5 volt heater.
837 β An indirectly heated pentode giving 11 watts at 20Β MHz and 5 watts at 80Β MHz. operating in Class-C. 12.6 volt heater.
838 β A directly heated triode giving about 100 watts at 30Β MHz operating in Class-C. 10 volt heater/filament.
841 β A directly heated high-mu triode giving about 10 watts at 6Β MHz and 5 watts at 170Β MHz operating in Class-C. 7.5 volt heater/filament.
842 β A directly heated triode giving about 3 watts at 6Β MHz operating in Class-C. 7.5 volt heater/filament.
843 β An indirectly heated tetrode giving gain at 6Β MHz and usable up to 200Β MHz operating in Class-C. 2.5 volt heater/filament.
844 β A directly heated triode giving gain at 6Β MHz and usable up to 155Β MHz operating in Class-C. 2.5 volt heater/filament.
845 β A directly heated triode giving up to 24 watts of undistorted power in Class-A at audio frequency with an anode voltage of 1250. 10 volt heater/filament.
849 β A directly heated triode giving gain at 3Β MHz operating in Class-C. Two 849s, working in push-pull Class-B are capable of delivering 1.1Β kW of audio output with an anode voltage of 3Β kV. Usable up to 30Β MHz. 11 volt filament/heater.
850 β A directly heated tetrode giving 120 watts of power gain up to 13Β MHz and 50 watts at 100Β MHz, operating in Class-C. 10 volt heater/filament.
851 β A directly heated triode giving 1.5Β kW of power up to 3Β MHz operating in Class-C. 11 volt heater/filament.
852 β A directly heated triode giving 75Β W of power up to 30Β MHz operating in Class-C. 10 volt heater/filament.
857B β Large mercury-vapor rectifier used in 50Β kW class broadcast transmitters. 22Β kV anode voltage, 10Β A anode current. Filament 5Β V @ 30Β A
860 β A directly heated tetrode giving 105Β W of power up to 30Β MHz and 50Β watts at 120Β MHz operating in Class-C. 10 volt heater/filament.
861 β A directly heated triode giving 400Β W of power up to 20Β MHz and 200 watts at 60Β MHz operating in Class-C. 11 volt heater/filament.
862 β Large water-cooled triode for broadcast/industrial applications. Used in experimental 500Β kW transmitter at WLW.
864 β A directly heated general-purpose, low-microphonics triode with a maximum anode voltage of 135Β volts and anode current of 3.5Β mA. 1.1Β volt heater/filament.
865 β A directly heated tetrode giving 30Β W of power up to 15Β MHz 15 watts at 70Β MHz operating in Class-C. 7.5 volt heater/filament.
866 β A mercury-vapor rectifier with a peak inverse voltage of 5Β kV and peak anode current of 1 ampere. Average anode current, 250Β mA, forward drop, 15 volt. Heater voltage and current, 2.5 at 5Β A. American 4-Pin(UX) base.
866A β Improved 866 with a peak inverse voltage of 10Β kV and a forward drop of 10 volt.
β A mercury-vapor rectifier with a peak inverse voltage of 5Β kV and peak anode current of 5 amperes. Average anode current, 1250Β mA, forward drop, 15 volt. Heater voltage, 5.0 at 10Β A. Base fits R.C.A. UT-541A Socket.
872A β Improved 872 with a peak inverse voltage of 10Β kV, a forward drop of 10 volt and a heater current of 6.25Β A.
879 β A high vacuum rectifier with a peak inverse voltage of ca. 15Β kV and peak anode current of ca. 5Β mA. 2.5 volt heater and American 4-Pin, (UX) base. Used as half wave rectifier for high voltage cathode ray tube supplies. Similar to type 2X2.
884 β An indirectly heated triode thyratron. 6.3 volt heater/filament, Octal base. Electrically similar to type 885. Once commonly used as a sawtooth horizontal sweep waveform generator in recurrent-sweep oscilloscopes. Marketed by DuMont under the type number 6Q5.
885 β An indirectly heated triode thyratron. 2.5 volt heater/filament, American 5-Pin (UY) base. Otherwise similar to type 884.
898 β Large water-cooled triode for broadcast/industrial applications. Updated version of 862, with 3-phase filament structure.
9
900s
934 β Vacuum Phototube, spectral S4 response (maximum sensitivity at 400Β±50Β nm), 3-pin Small-Shell Peewee base
935 β Vacuum Phototube, spectral S5 response (maximum sensitivity at 340Β±50Β nm), 4-pin octal base
950 β Power pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to types 1F4 and 1J5G
951 β Sharp-cutoff pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to type 1B4P
953 β Acorn-type UHF diode; 6.3Β V heater
954 (4672/E1F) β Indirectly heated Acorn-type sharp-cutoff pentode giving gains of 2...3 up to 300Β MHz operating in Class-A and usable up to 600Β MHz with careful stage design; 6.3Β V heater
955 (4671/E1C) β Indirectly heated Acorn-type triode giving a power of 135Β mW up to 600Β MHz operating in Class-A and 500Β mW in Class-C with careful stage design; 6.3Β V heater
956 (4695/E2F) β Indirectly heated Acorn-type remote-cutoff pentode giving gains of 3...4 up to 600Β MHz operating in Class-A with careful stage design; 6.3Β V heater
957 (D1C) β Directly heated Acorn-type UHF receiving triode; 1.25Β V filament for portable equipment
958 (D2C) β Directly heated Acorn-type UHF transmitting triode with dual, paralleled 1.25Β V filaments for increased emission, for portable equipment
958A β 958 with tightened emission specs
959 (D3F) β Directly heated Acorn-type sharp-cutoff UHF pentode; 1.25Β V filament for portable equipment
991 β 60-Volts Voltage reference, T lightbulb with 2-contact, bayonet candelabra mount
9000s
9001 β 954 with a miniature 7-pin base
9002 β 955 with a miniature 7-pin base
9003 β 956 with a miniature 7-pin base
9004 β Acorn UHF diode
9005 β Acorn UHF diode with a 3.6Β V heater
9006 β Detector diode with a miniature 7-pin base
List of other letter tubes
A
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
A40 β Acorn UHF triode up to 600Β MHz, 4Β Volts heater
A41 β Acorn UHF pentode up to 600Β MHz, 4Β Volts heater
AC*/
Mazda/EdiSwan 4-volts AC, indirectly heated receiver tubes:
AC/HL β AF triode, British 5-pin base
AC/HLDD = TDD4 = MHD4 β Dual diode and AF triode, British 7-pin base
AC/ME β Tuning indicator, British 7-pin base
AC/P, AC/P1 β AF triode, British 5-pin base
AC/P4 β CRT electrostatic-deflection output power triode, British 5-pin base
AC/PEN β AF power pentode, British 7-pin base
AC/S2PEN β RF pentode, British 7-pin base
AC/SP1 β RF pentode for use in squelch circuits or, as the reactance tube, in AFC circuits, British 7-pin base
AC/SP3 β RF pentode for shortwave and TV receivers, British 7-pin base
AC/SP3/RH β Low-noise, low-microphonics RF pentode for shortwave and TV receivers, British 7-pin base
AC/TH1 β Triode/hexode oscillator/mixer, British 9-pin base
AC/TP = TP4 β Triode/pentode oscillator/mixer, British 7-pin base
AC/VP1, AC/VP2 β RF pentode, British 7-pin base
AC2/HL β High-mu triode
AC2/PEN β AF Power pentode
AC2/PEN.DD β Dual diode and AF Power pentode
AC4/PEN β AF Beam power pentode
AC5/PEN β AF Beam power pentode
AC5/PEN.DD β Dual diode and AF Beam power pentode
AC6/PEN β Beam power pentode for use as a magnetic horizontal-deflection output amplifier
ACT
Marconi-Osram Valve Company
ACT9 β 800Β W Air cooled transmitting triode up to 15Β MHz, with derating up to 80Β MHz
B
BA
Industrial Electronic Engineers:
BA-0000-P31 β Nimo tube, cathode-ray 1-digit numeric display tube, 10 stenciled electron guns aiming at a P31-phosphor (yellowish-green, medium-persistence) fluorescent screen, top-viewing, Futura Medium font, 2.5Β kV anode voltage, 12-pin base
BG
Burroughs Neon-filled planar glow-transfer plasma bar graph displays:
BG08220-K β 120-Segment circular with five cathode strings plus a Reset cathode, 1-in-5 major/minor graduation, for use e.g. in direction-finding equipment
BG12201 = Dale PBG12201 β Dual 201-segment linear with three cathode strings plus a Reset cathode, for use in VU meters etc.
BG12203 = PBG12203 β Dual 203-segment linear bidirectional with three cathode strings plus two Reset cathodes
BG12205 = PBG12205 β Dual 201-segment linear with five cathode strings plus a Reset cathode, for use in VU meters etc.
BG16101 = PBG16101 β Dual 101-segment linear with three cathode strings plus a Reset cathode, for use in VU meters etc.; cf. ΠΠ-33
BT
British Thomson-Houston (General Electric subsidiary):
BT1 β Thyratron used in Wynn-Williams' binary prescaler for the alpha particle counter that Rutherford, Chadwick et al. used for their nuclear research at the Cavendish Laboratory in the 1930s
C
CH
Tung-Sol:
CH1027 β Curristor β Four types of nitrogen-filled, radioactive constant-current tubes with a current plateau from 25 to 500Β V, all-glass wire-ended, active material is 226Ra with a half-life of 1601 years, for linear capacitor charging and draining in missile and ordnance mine timing circuits, instrumentation biasing, as current reference, etc.:
CH1027-9 β 10β9Β A,
CH1027-10 β 10β10Β A,
CH1027-11 β 10β11Β A,
CH1027-12 β 10β12Β A,
CK
Raytheon:
CK1022 β 1Β kV/5...55Β ΞΌA Corona voltage reference, miniature 7-pin base with anode top cap
CK1037 = 6437 β 700Β V/5...125Β ΞΌA Corona voltage reference, 3-pin all-glass wire-ended
CK1038 β 900Β V/5...55Β ΞΌA Corona voltage reference, 3-pin all-glass wire-ended
CK1039 = 6438 β 1.2Β kV/5...125Β ΞΌA Corona voltage reference, 3-pin all-glass wire-ended
CK1366, CK1367, CK1368, CK1369 β CRTs with an unphosphored front glass but with fine wires embedded in it for use as electrostatic print heads; the wires would pass the electron beam current through the glass onto a sheet of paper where the desired content was therefore deposited as an electrical charge pattern. The paper was then passed near a pool of liquid ink with the opposite charge. The charged areas of the paper attract the ink and thus form the image.
CK1383 β Dual-electron gun recording storage tube, a realtime polar, radar PPI-to-rectangular, TV-type analog video transcoder similar to the 7702, with simultaneous R/W, and storing capability. This was achieved by a CRT/camera tube combination; the CRT part writes the PPI-format image onto a thin, dielectric target; the camera part reads the generated charge pattern in TV format from the back side of this target.
CK1414 β Symbolray character generator monoscope for text mode video rendering in early computer monitors, with a square target having letters, digits and symbols patterned on it in a customer-supplied 8x8 or 8x12 array. An electron beam selects and scans a character, both by appropriate electrostatic deflection, and generates an analog video signal; cf. 4560, TH9503
CL
Ferranti:
CL40 and CL41 β Indirectly heated, linear light source (glow modulator tube), mercury/argon-filled gas diode with primer electrode, Octal base, for rotating-drum FAX receivers, film soundtrack recording, etc.
CL42 and CL43 β Indirectly heated, low-noise linear light source, helium-filled gas diode with primer electrode, Octal base, for film soundtrack recording, interferometers, etc.
CL44 β Indirectly heated, low-noise linear light source, neon-filled gas diode with primer electrode, Octal base
CL50 and CL52 β Indirectly heated, linear light source, gas-filled diode with primer electrode, Miniature 7-pin base, for rotating-drum FAX receivers, film soundtrack recording, etc.
CL55 β Indirectly heated, spectrally pure light source, helium-filled gas diode with primer electrode, Miniature 7-pin base with anode top cap
CL56 β Indirectly heated, spectrally pure light source, krypton-filled gas diode with primer electrode, Miniature 7-pin base with anode top cap
CL57 β Indirectly heated, spectrally pure light source, neon-filled gas diode with primer electrode, Miniature 7-pin base with anode top cap
CL58 β Indirectly heated, spectrally pure light source, xenon-filled gas diode with primer electrode, Miniature 7-pin base with anode top cap
CL60 β Indirectly heated triode flood beam CRT-type stroboscope lamp with a green A-type phosphor with <1Β ΞΌs decay time and 10Β kCd light output, 20Β kV anode voltage, 7-pin duodecal base
CL61 β CL60 with a blue P-type phosphor with 5Β ΞΌs decay time and 16Β kCd light output
CL62 β CL60 with an UV Q-type phosphor with 100Β ns decay time and 240Β Cd light output
CL63 β CL60 with a yellow-green C-type phosphor with 6Β ΞΌs decay time and 24Β kCd light output
CL64 β CL60 with a yellow V-type phosphor with 5Β ΞΌs decay time and 12Β kCd light output
CL65 β CL60 with a red R-type phosphor with 2Β ΞΌs decay time and 14Β kCd light output
CL66 β CL60 with a white T-type phosphor with 5Β ΞΌs decay time and 12Β kCd light output
D
Philips:
D1 β Early directly heated triode used in 1920s TRF and regenerative radios
DDR
Mullard:
DDR100 β 100Β g max., 250Β Hz max., 1-axis accelerometer dual diode with elastically supported anodes, 6.3V/600mA indirect heater, fres = 1Β kHz, B8G base
DZ
Cerberus:
DZ10 β 3Β kHz max. Decade Counter/Selector Dekatron, 14-pin diheptal base
E
EN
Ferranti:
EN10 β Neostron, 400Β Apk Gas-filled, cold-cathode tetrode thyratron, differential trigger electrodes, Octal base, for use as a relay or as a reddish 700Β Cd stroboscope lamp
EN15 β 80Β Aavg Neon-filled, cold-cathode tetrode thyratron, differential trigger electrodes, Noval base, for use as a stroboscope lamp
EN30 β 250Β Apk Gas-filled, arc-discharge cold-cathode tetrode thyratron, differential trigger electrodes, miniature 7-pin base with anode cap, for use as a relay or as a stroboscope lamp
EN40 β 250Β Apk Gas-filled, cold-cathode tetrode thyratron, differential trigger electrodes, Octal base, for use as a whitish stroboscope lamp with a high actinism for photographic film
EN55 (Single), EDN10 (dual) β Xenon-filled, arc-discharge cold-cathode tetrode thyratron, external (capacitive) trigger, 12-pin base, for use as a white 140Β kCd stroboscope lamp
EN60 β Gas-filled, arc-discharge cold-cathode tetrode thyratron, external (capacitive) trigger, Edison screw lamp base with anode cap, for use as a white 900Β klm@10ΞΌF@800V stroboscope lamp
G
Standard Telephones and Cables/Brimar:
G10/241E β Nomotron, a unidirectional Dekatron with multi-alloy cathodes
Cerberus:
G11 β 5Β mA Gas-filled, cold-cathode switching diode e.g. for relaxation oscillators, 2-pin all-glass wire-ended
G42 β 35Β mApeak Gas-filled switching diode e.g. for relaxation oscillators, 2-pin all-glass wire-ended
GE
Ferranti:
GE10 β Directly heated saturated-emission diode. Acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits. It has two shorted pins that can be used to disable the circuit if the tube is removed from its socket
GK
Cerberus:
GK11 β Touch button tube, an illuminated capacitance touch switch; a cold-cathode DC relay tube, external (capacitive) starter activated by touching; then the cathode glow is visible as an orange ring. 2-pin all-glass wire-ended
GN
Ferranti:
GN10 β 250 Amps pulse-current, cold-cathode tetrode thyratron. Octal base
GR
Cerberus:
GR15 β 15Β mA Gas-filled cold-cathode DC tetrode, one starter and one electrical primer and tritium-primed (half-life: 12.32 years), noval base, for voltage triggers, RC timers etc.
GR16 β 20Β mA Gas-filled, cold-cathode, tritium-primed AC/DC triode, one starter and an EM shield, noval base, for voltage triggers, RC timers etc.
GR17 β 15Β mA Gas-filled cold-cathode AC triode, one starter and an EM shield, noval base, for voltage triggers, RC timers etc.
GR31 β 15Β mA Gas-filled cold-cathode DC tetrode, one starter and one electrical primer plus a tritium primer, noval base
GR44 β 12Β mA Subminiature gas-filled cold-cathode DC pentode, two starters and one primer electrode plus a tritium primer, 5-pin all-glass wire-ended
GR46 β 12Β mA Subminiature gas-filled cold-cathode DC tetrode, one starter and one primer electrode, 4-pin all-glass wire-ended
GRD
Ferranti:
GRD7 β Educational, directly heated saturated-emission guard ring diode
K
KN
Edgerton, Germeshausen, and Grier:
KN2 β 4Β kV, 500Β Asurge Krytron, a cold-cathode gas-filled tube with a primer electrode, for use as a very high-speed, high-surge current switch; similar to a thyratron, lifespan 107 shots, 4-pin all-glass wire-ended
KN4 β 5Β kV, 2.5Β kAsurge Krytron with a primer electrode, lifespan 25000 shots, 4-pin all-glass wire-ended
KN6 β 5Β kV, 3Β kAsurge Krytron with a primer electrode, lifespan 35000 shots, 4-pin all-glass wire-ended
KN6B β 8Β kV, 3Β kAsurge Krytron with a primer electrode, lifespan 35000 shots, 4-pin all-glass wire-ended
KN9 β 4Β kV, 500Β Asurge Krytron with a primer electrode, lifespan 1.5Γ107 shots, 4-pin all-glass wire-ended
KN11B β 2.5Β kV, 1.5Β kAsurge Sprytron, lifespan 2000 shots, 3-pin all-glass wire-ended
KN12 β 5Β kV, 3Β kAsurge Sprytron, lifespan 500 shots, 3-pin all-glass wire-ended
KN22 β 5Β kV, 100Β Asurge Krytron with a primer electrode, lifespan 2Γ107 shots, 4-pin all-glass wire-ended, for laser pumping, to drive Pockels cells, also for educational purposes
KN26 β 5Β kV, 3Β kAsurge Krytron with a primer electrode, lifespan 75000 shots, 4-pin all-glass wire-ended
KT
"Tung-Sol":
KT90
KT120 β New production tube
KT150 β New production tube
KT170 β New production tube
M
MC
Philips:
MC6-16, MC13-16 β CRT-type flying-spot scanners, P16-type phosphor (violet/near-ultraviolet, very short persistence), for use in a telecine
ME
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
ME91 β AC/DC mains tuning indicator
P
PD
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
PD220 β Dual AF power triode for battery-supplied equipment (1939)
PL
Philips:
PL21 = 2D21 = EN91 β 100Β mAavg, 500Β mApeak, 10Β Asurge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for relay and grid-controlled rectifier service
PL323 = 3C23 β 1.5Β Aavg, 6Β Apeak, Mercury-vapor triode thyratron, 4-pin base with anode top cap
PL5727 = 5727 β 100Β mAavg, 500Β mApeak, 10Β Asurge, Tetrode thyratron, 7-pin miniature base
Q
Philips:
Q13-110GU β CRT-type flying-spot scanner, white phosphor, for use in a telecine
QK
Raytheon:
QK329 β Beam-deflection square-law tube for use as a function generator in analog computers. A flat sheet beam is electrostatically deflected across the anode which is partially covered by a parabolically stenciled screen "grid" that acts as the tube's output. Two tubes may be combined to form a 1-quadrant analog multiplier using the equation where the deflection electrode signals and can be obtained directly from a fully balanced resistor bridge
R
Marconi-Osram Valve Company:
R β Early directly heated triode derived from the French TM tube and used by many amateurs in the 1920s
RK
Raytheon:
RK61 β Miniature, gas-filled, directly heated thyratron designed specifically to operate like a vacuum triode below its ignition voltage, allowing it to both amplify analog signals and work as a relaxation oscillator, for use as a self-quenching superregenreative detector up tp 100Β MHz in radio control receivers, activating a relay in its anode circuit when a carrier wave is received; 4-pin all-glass wire-ended, 1.4Β V, 45Β mA filament, Ua=45Β V, Ia=1.5Β mA.
RK62 β RK61's predecessor, marketed since 1938; this was the major technical development which led to the wartime development of radio-controlled weapons and the parallel development of radio controlled modelling as a hobby.
S
SB
Radio Corporation of America:
SB256 β 256-bit Selectron tube, an early form of digital computer memory
SU
Cossor:
SU25 β EHT rectifier
SU2150 (CV1120) β High-voltage vacuum half-wave rectifier for use in CRT power supplies
T
British General Electric Company:
TuneOn β Early neon-filled bar graph tuning indicator, a glass tube with a short wire anode and a long wire cathode that glows partially; the glow length is proportional to the tube current
TuneOn Button β Early glow modulator used as a budget-priced tuning indicator β a neon lamp whose brightness is proportional to the tube current
Standard Telephones and Cables/Brimar:
Tunograph β Precursor of the "Magic Eye" tuning indicator first introduced in 1933; a tiny CRT with 1-axis electrostatic deflection and a phosphored target at 45Β° to the electron beam, so the projected green dot can be observed from the side
TH
Compagnie Française Thomson-Houston:
TH9503 β Scripticon, a character generator monoscope for text mode video rendering in early computer monitors, with a square target having letters, digits and symbols patterned on it in an (optionally customer-supplied) 8x8 array. An electron beam selects and scans a character, both by appropriate magnetic deflection, and generates an analog video signal; cf. 4560, CK1414
TM
E.C.&A. Grammont and Compagnie des Lampes (1888):
TM β Vacuum triode for amplification and detection of radio signals, developed in France and made since 1915. It became the standard receiving and amplifying tube of the Entente countries during World War I, and the first mass-produced radio tube. TM's production volume in France alone is estimated at 1.1 million units; in addition, the production of TM and/or improved versions was started in the UK (MarconiβOsram R tube), the Netherlands (Philips E tube), the United States and the Soviet Union (R-5, Russian: Π -5).(ru)
The TM was developed in 1914β15 by the French military telecommunications service TΓ©lΓ©graphie Militaire on the initiative of their technical director Gustave-Auguste FerriΓ©. He and his assistant, physicist Henri Abraham, visited the American laboratories on a number of occasions and were aware of the works of Lee de Forest, Reginald A. Fessenden and Irving Langmuir. They knew that de Forest's Audion and Henry Round's British tube were unreliable and imperfect, and Langmuir's Pliotron was too complex for mass production. They also knew about the latest German developments: Soon after the outbreak of the war, FerriΓ© received extensive information from a former Telefunken employee, the Frenchman Paul Pichon, who, upon return from a mission from his German employer to gather samples of the latest triodes from the USA, had to surrender himself and the samples to the French. The samples Pichon brought performed poorly due to insufficient vacuum. Following the ideas of Langmuir, FerriΓ© required the industry to guarantee a high vacuum in series production.
In October 1914, Ferrié, Abraham and François Péri from the radiotelegraph centre in Lyon/La-Doua(fr) went to the light bulb department of Société des Téléphones E.C.&Alexandre Grammont in Lyon to develop with them a triode suitable for mass production. The first prototypes, mere copies of de Forest's Audion, proved to be unreliable and unstable; the next ones were rejected for being too complex. Only the fourth prototype developed in December 1914, with a vertical coaxial system, an Edison screw lamp base for the filament and additional side terminals for anode and grid, was deemed suitable for series production, which started in February 1915 and stopped in October 1915 when it became clear that the vertical structure of "Abraham's Lamp" was too fragile and too many tubes were damaged during transport. Ferrié asked Péri to resolve the problem, and two days later Péri and Jacques Biguet came up with a horizontal coaxial system on the latest four-pin type European 4-pin base. The series production of the Péri/Biguet tubes, named TM after Ferrié's service unit, began in November 1915 under Grammont's Radio Fotos brand; this variant became highly successful, and when demand started to exceed Grammont's production capacity, Compagnie des Lampes (1888) in Ivry-sur-Seine also started production under their Métal brand. Ferrié and Abraham were nominated for the 1916 Nobel Prize in Physics for their work in the field of radio communications.
The TM is a cylindrical/coaxial triode; the directly-heated cathode is a filament made of pure tungsten with a diameter of 60Β ΞΌm, the anode is a nickel cylinder with a diameter of 10Β mm and a length of 15Β mm. The dimensions and material of the grid depend on the place of production β the Grammont plant in Lyon used molybdenum wire, the CdL plant in Ivry-sur-Seine used nickel. The diameter of the grid spiral is 4 resp. 4.5Β mm. The filament required 4Β V and 700Β mA to bring it up to white heat; the bright glow prompted Grammont in 1923 to start producing TM tubes with dark blue glass envelopes to protect the eyes of radio operators from the blinding glare, and hide the harmless, but unsightly plaque of metal particles inevitably deposited on the inner wall of the bulb while evacuating during production β but also prevented the triodes' previous, secondary use as light sources, which had earned them their nickname Loupiote ("little lamp").
The TM could be used for their intended purpose, amplifying and detecting signals in radio receivers, or as power oscillators in low-power radio transmitters, and also, by paralleling of several tubes, as AF power amplifiers. The Soviet analogue of the TM, the triode R-5, could withstand anode voltages of up to 500...800Β V, and was able to deliver a power of up to 1Β W in Class-C mode, but only 40Β mW in Class-A mode. A typical single-TM radio receiver of World War I ran at Ua=40Β V, Ug=0Β V, Iaβ2Β mA, gm=400Β ΞΌS, Ri=25Β kΞ©, ΞΌ=10. With an anode voltage of 160Β V and a grid bias of -2Β V, the anode current was 3...6Β mA, while the reverse grid current reached 1Β ΞΌA.
The problem of TM tubes was their short service life of 100Β hours maximum β if the tube was manufactured in strict accordance with the specifications. In wartime, this was not always possible; due to raw materials supply problems, plants sometimes had to use substandard materials. Such tubes were marked with a cross; they differed from the standard by a higher noise level and were prone to catastrophic failures due to cracks in the glass envelope.
TT
Bendix:
TT8, TT9, TT13, TT15, TT17, TT18, TT20, TT21, TT22 β Chronotron, integrating, balanced-bridge hot-wire/PTC time delay devices
Marconi-Osram Valve Company:
TT11 β Low power VHF transmitting beam tetrode
TT21 β RF power beam-tetrode derived from KT88
TT100 β RF power beam-tetrode
V
VHT
Ferranti:
VHT1 β Pentagrid converter, 1933
Lettered Loctal tubes used in Philco radios
FM1000 β Unusual pentagrid for use as oscillator and coincidence-type phase detector in a PLL FM quadrature detector. The anode signal is loosely coupled into the oscillator tank and pulls it to stay quadrature-phase-locked with the IF; manufactured by Sylvania and used in Philco AM/FM radios of the late 1940s and early 1950s. Predecessor of the nonode approach
XXB β Medium-mu twin triode, also numbered 3C6/XXB
XXD β Medium-mu twin triode, also numbered 14AF7/XXD
XXFM β High-mu triode, twin diode (one shares its cathode with the triode, one with separate cathode), also numbered 7X7/XXFM
XXL β Medium-mu triode, also numbered 7A4/XXL
List of tubes used in 1920s and 1930s radio receivers
Directly heated
Used with AC, DC or home-based storage battery power supplies (1927β31)
1.1 Volt DC filament
Used in 1920s home radios. Filaments powered by 1.5 volt dry cells, anodes powered by storage batteries.
WD-11 β triode/detector
2 Volts DC filament
Used in 1930s home radios powered by storage batteries.
19 β Dual power triode β also used in farm radios with 6-volt vibrator power supplies. Early version of octal type 1J6G.
20 β Power triode β Early versions numbered UX-120.
22 β Sharp-cutoff tetrode β Early versions numbered UX-222 or CX-322.
25S β Dual detector diode, medium-mu triode. Identical to type 1B5. Usually numbered 1B5/25S.
30 β Medium-mu triode, An upgraded version of type 01-A β Early versions numbered RCA-230 or CX-330. Can also be used as a power triode. The type 30 was popular amongst amateurs of the day. Early UX4 based version of octal type 1H4G.
31 β Power triode, UX4 based β Early versions numbered RCA-231 or CX-331.
32 β Sharp-cutoff tetrode β Early versions numbered RCA-232 or CX-332.
33 β Power pentode β Early versions numbered RCA-233 or C-333.
34 β Remote-cutoff tetrode β Early versions numbered RCA-234 or CX-334.
49 β Dual-grid power triode, similar to type 46
3.3 Volts DC filament
Used in 1920s home radios powered by dry cells (filaments) and storage batteries (B-plus voltage).
V99 β Low-mu triode. Except for stub-pin bayonet base and pinout, electronically similar to X99
X99 β Similar to V99, but with standard pins and different basing arrangement (pinout).
4 Volts DC filament
3NF β Tube-based "integrated circuit" with 3 triodes and passive components in the same envelope. 4V heater
5 Volts DC filament
Used in 1920s home radios powered by storage batteries.
00-A β Detector triode with a trace of argon. "00-A" is the number used in most tube manuals. Numbers for earlier versions include UX-200-A and CX-300-A (long pins, push-in socket) and UV-200-A (stub pins, bayonet socket).
01-A β All-purpose low-mu triode, used as RF amplifier, detector, AF amplifier and power triode. The most popular tube of the 1920s. "01-A" is the number used for replacements manufactured after 1930 and in tube manuals. Numbers for early versions include UX-201-A and CX-301-A (long pins, push in socket) and UV-201-A (stub pins, bayonet socket).
Note: There were four tubes in the "01" series, each with different current ratings for their filaments. Type 01-A was the most commonly used.
Types UV 201 and UX 201 β 1.0 ampere
Type 01-A (UV 201-A, UX 201-A, etc.) β 250 milliampere
Type UX 201-B β 125 milliampere
Type UX 201-C β 60 milliampere
12-A β Medium-mu triode, often used as detector, audio driver or audio output, but not as an RF amplifier. This type is listed in tube manuals after 1930 for replacements purposes. Also referred to as type 112-A. Many early versions are marked UX-112-A or CX-112-A.
40 β Medium-mu triode β Early versions numbered UX-240. Introduced in 1927, this was an upgraded version of the "01" series. The "01" series had an amplification factor of 8, while type 40 had an amplification factor of 30. (By comparison, the two AC triodes introduced in the same time period β types 26 and 27 β had amplification factors of 8.3 and 9, respectively.) Because this was the highest-amplification triode available, advertising literature of the time lists it as a high-mu triode, although it is now classified as a medium-mu triode. Type 40 had the highest amplification factor of any triode until the introduction in 1932 of diode/triode complex type 2A6, which had an amplification factor of 100. It also had the highest amplification factor of any DC filament triode until the introduction in 1939 of complementary diode/triode complex types 1H5GT (octal) and 1LH4 (Loctal), which both had amplification factors of 65.
Directly AC-heated power tubes
10 β Power triode β Early versions numbered UX-210 or CX-310.
26 β Medium-mu triode, used in early AC radio receivers manufactured in the late 1920s. Used as an RF or AF amplifier, but not as a detector or power output tube β Early versions numbered UX-226 or CX-326.
45 β Power triode β Early versions numbered UX-245 or CX-345.
46 β Dual grid power triode β Grids 1 and 2 connected together for use as push-pull Class-B outputs, Grid 2 and anode connected together for use as single-tube audio driver.
47 β Power pentode β Early versions numbered RCA-247 or C-347.
50 β Power triode β Early versions numbered UX-250 or CX-350.
71-A β Power triode β This type listed in tube manuals after 1930 for replacements purposes. Also referred to as 171-A. Many early versions numbered as UX-171-A or CX-371-A.
Directly AC-heated rectifier tubes
80 β Full-wave rectifier used in early power supplies or battery eliminators (electronically similar to 5Y3G) β Early versions numbered UX-280 or CX-380; derived from the 13 (UX-213)
81 β Half-wave rectifier β Early versions numbered UX-281 or CX-381; derived from the 16-B (UX-216-B)
82 β Full-wave mercury-vapor rectifier
83 β Full-wave mercury-vapor rectifier
83-V β High-vacuum version of type 83, Early UX4 based version of octal type 5V4G.
Indirectly heated
DC heater
15 β Sharp-cutoff pentode, used in farm radios, in autodyne circuits requiring a separate cathode.
2.5 Volts heater
Powered by an AC transformer
24 β Sharp-cutoff tetrode, UX5 based, Early versions numbered UY-224 and C-324
24-A β an upgraded version of type 24, see type 24 above. Early versions numbered UY-224A and C-324A
27 β Medium-mu triode, UX5 based, Early versions numbered UY-227 and C-327. The first North American tube with an indirectly heated cathode, which is necessary for detector circuits in AC powered tube radios.
29 β Wunderlich detector. Known to have been manufactured by Sylvania.
35 β Remote-cutoff tetrode, UX5 based, (Commonly branded as 35/51). Early versions numbered UY-235 or C-335
51 β Similar to 35, see type 35 above. (Commonly branded as 35/51)
53 β Dual power triodes, Class-B, UX7 based, (Except for heater, electronically similar to 6A6 and octal based 6N7)
55 β Dual diode, medium-mu triode, UX6 based, (Except for heater, electronically similar to type 85, and octal based 6V7G, but not to 75)
56 β Medium-mu triode, UX5 based, (Except for heater, electronically similar to 76, and octal based 6P5G)
57 β Sharp-cutoff pentode used in cabinet and mantel radio receivers, UX6 based, (Except for heater, electronically similar to 6C6 and octal based 6J7G, and somewhat similar to type 77)
58 β Remote-cutoff pentode, UX6 based, (Except for heater, electronically similar to 6D6 and octal based 6U7G, but not to 78)
59 β Power pentode, UX7 based.
90 β Wunderlich detector
95 β Original number of type 2A5
4 Volts heater
2HF β Tube-based "integrated circuit" with 2 tetrodes and passive components in the same envelope
6.3 Volts heater
Powered by an AC transformer or a vehicle crank battery
1-V β Half-wave rectifier, UX4 based, (often branded as type 1V/6Z3). Early version was KR-1.
36 β Sharp-cutoff tetrode, UX5 based. Early versions numbered RCA-236 or C-336
37 β Medium-mu triode, UX5 based. Early versions numbered RCA-237 or C-337
38 β Power pentode, UX5 based. Early versions numbered RCA-238
39 β Remote-cutoff pentode, UX5 based (Commonly branded as 39/44).
41 β Power pentode, Early UX6 based version of octal type 6K6G, and Loctal type 7B5.
42 β Power pentode, Early UX6 based version of octal type 6F6G, Except for heater, similar to types 2A5 and 18.
44 β Similar to type 39, see type 39 above. (Commonly branded as 39/44).
64 β Sharp-cutoff tetrode (Except for 400 milliampere heater, similar to 36)
65 β Remote-cutoff pentode (Except for 400 milliampere heater, similar to 39)
67 β Medium-mu triode (Except for 400 milliampere heater, similar 37)
68 β Power pentode (Except for 400 milliampere heater, similar to 38)
69 β Wunderlich detector
70 β Wunderlich detector used in Mission Bell model 19 car radio. Listed in early Philco tube lists.
75 β Dual diode, high-mu triode. Early UX6 based version of octal types 6B6G & 6SQ7GT, and Loctal type 7B6, and 7-pin miniature type 6AV6. Also except for heater, electronically similar to 2A6.
76 β Medium-mu triode, Early UX5 based version of octal type 6P5G.
77 β Sharp-cutoff pentode, Early UX6 based version of octal type 6J7G.
78 β Remote-cutoff pentode, Early UX6 based version of octal type 6K7G.
79 β Dual power triode, Early UX6 based version of octal type 6Y7G.
84 β Full-wave rectifier, often branded as type 84/6Z4. Early UX5 based version of octal type 6X5GT, and Loctal 7Y4, and 7-pin miniature 6X4.
85 β Dual diode, medium-mu triode. Early UX6 based version of octal type 6V7G, except for heater voltage similar to type 55. Also somewhat similar to octal type 6SR7GT and 7-pin miniature types 6BF6.
89 β Power pentode, UX6 based.
92 β Wunderlich detector
AC/DC series heater
14 β Similar to 24-A but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
17 β Similar to 27 but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
18 β Similar to 2A5 and 42 but with a 14 volt, 300 milliampere heater. No known commercial use.
43 β Power pentode, Early UX6 based version of octal type 25A6G
48 β Power tetrode, used in 32-volt farm radios. When two are parallel-connected, they can operate with anode and screen voltages as low as 28 volt.
WG38 β Tube-based "integrated circuit" with 2 pentodes, a triode and passive components in the same envelope
Shielded tubes for Majestic radios
In the early 1930s, the Grigsby-Grunow Company β makers of Majestic brand radios β introduced the first American-made tubes to incorporate metal shields. These tubes had metal particles sprayed onto the glass envelope, copying a design common to European tubes of the time. Early types were shielded versions of tube types already in use. (The shield was connected to the cathode.) The Majestic numbers of these tube types, which are usually etched on the tube's base, have a "G" prefix (for Grigsby-Grunow) and an "S" suffix (for shielded). Later types incorporated an extra pin in the base so that the shield could be connected directly to the chassis.
Replacement versions from other manufacturers, such as Sylvania or General Electric, tend to incorporate the less expensive, form-fitting Goat brand shields that are cemented to the glass envelope.
Grigsby-Grunow did not shield rectifier tubes (except for type 6Y5 listed below) or power output tubes.
Early types based on existing tubes. (Non-shielded versions may be used, but add-on shielding is recommended.)
G-2A7-S β Pentagrid converter
G-2B7-S β Semiremote-cutoff pentode, dual detector diode
G-6A7-S β Pentagrid converter
G-6B7-S β Semiremote-cutoff pentode, dual detector diode
G-6F7-S β Remote-cutoff pentode, medium-mu triode
G-25-S β Medium-mu triode, dual detector diode for 2.0 volt storage battery radios. Glass type 1B5/25S used for replacement.
G-51-S β Remote-cutoff tetrode
G-55-S β Medium-mu triode, dual detector diode
G-56-S β Medium-mu triode
G-56A-S β Medium-mu triode, original version of type 76, but with 400 milliampere heater. (Not to be confused with types 56 or G-56-S, which has a 2.5 volt, 1.0 ampere heater.)
G-57-S β Sharp-cutoff pentode
G-57A-S β Sharp-cutoff pentode, original version of type 6C6, but with 400 milliampere heater. (Not to be confused with types 57 or G-57-S, which has a 2.5 volt, 1.0 ampere heater.)
G-58-S β Remote-cutoff pentode
G-58A-S β Remote-cutoff pentode, original version of type 6D6, but with 400 milliampere heater. (Not to be confused with types 58 or G-58-S, which has a 2.5 volt, 1.0 ampere heater.)
G-85-S β Similar to G-55-S, but with 6.3 volt heater.
Later types
6C7 β Medium-mu triode, dual detector diode, similar to later octal types 6R7 and 6SR7. Seven pin base. (Shield to pin 3.)
6D7 β Sharp-cutoff pentode, identical to type 6C6, but with 7-pin base. (Shield to pin 5.)
6E7 β Remote-cutoff pentode, identical to type 6D6, but with 7-pin base. (Shield to pin 5.)
6Y5 β Dual rectifier diode, similar to type 84/6Z4, but with 6-pin base. (Shield to pin 2.)
Other tubes unique to Majestic radios
G-2-S and G-4-S β Dual detector diodes with common cathodes. The first detector diodes packaged in a separate tube. Forerunners of octal type 6H6. Spray-shielded. Both tubes have 2.5 volt heaters. G-2-S is larger and has a 1.75 ampere heater. Type G-4-S has a 1.0 ampere heater. Later Sylvania replacement type 2S/4S has a 1.35 ampere heater.
2Z2/G-84 β Half-wave rectifier diode with 2.5 volt indirectly heated cathode. A lower-voltage version of type 81. Not interchangeable with type 6Z4/84.
6Z5 β Full-wave rectifier, similar to types 6Z4/84 and 6X5, but with 12.6 volt center-tapped heater.
Rarely used tubes
52 β Dual grid power triode similar to types 46 and 49. Has 6.3 volt filament. Most commonly used in early car radios
181 β Power triode
182-B β Similar to 482-B below.
183 β Similar to 483 below.
482-B β Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 182-B/482-B. Similar to type 71-A, but with higher anode voltage.
483 β Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 183/483. Similar to type 45, but with a 5.0 volt, 1.25 ampere heater.
485 β Medium-mu triode with indirectly heated cathode. Used in Sparton AC radios, circa 1929. Similar to types 56 and 76, but with a 3.0 volt, 1.25 ampere heater, and lower anode voltage.
References and footnotes
Specific items
General literature and data sheets
Frank Philipse's Tube Datasheet Archive
Mirrors in BrazilΒ β’ BrazilΒ searchableΒ β’ GermanyΒ β’ GermanyΒ β’ RomaniaΒ β’ RomaniaΒ searchableΒ β’ SwedenΒ β’ USAΒ β’ USΒ β’ US
Tubebooks.org datasheet collection
Roy J. Tellason's tube datasheet collection
Klausmobile Russian tube directory
General Electric Essential Characteristics, 1970
RCA Receiving Tube Manuals R10Β (1932)Β β’ RC11Β (1933)Β β’ RC12Β (1934)Β β’ RC13Β (1937)Β β’ RC14Β (1942)Β β’ RC15Β (1948)Β β’ RC16Β (1951)Β β’ RC17Β (1954)Β β’ RC18Β (1956)Β β’ RC19Β (1959)Β β’ RC20Β (1960)Β β’ RC21Β (1961)Β β’ RC22Β (1963)Β β’ RC23Β (1964)Β β’ RC24Β (1965)Β β’ RC25Β (1966)Β β’ RC26Β (1968)Β β’ RC27Β (1970)Β β’ RC28Β (1971)Β β’ RC29Β (1973)Β β’ RC30Β (1975)
Scanned tube documentation (PDFs): TubebooksΒ β’ Frank PhilipseΒ β’ 4tubes
Sylvania Technical Manual, 1958
J. P. Hawker (ed), Radio and television servicing, Newnes, London, 1964
Camera tube datasheets
Β β’ Decoding type numbers
Decoding Valve, Transistor and CRT Numbers
Vacuum Tube Numbering Schemes, Bases & Bulbs
European tube designation systems: Β β’ Β β’
See also
External links
Vacuum Tube Data Sheet Locator
Tube Substitution and Characteristics Guide
British virtual thermionic valve museum with good quality pictures and data
Belgian virtual thermionic valve museum with good quality pictures and data
Radio museum
Virtual Valve Museum
Electronics lists
Gas-filled tubes | List of vacuum tubes | [
"Physics"
] | 67,100 | [
"Vacuum tubes",
"Vacuum",
"Matter"
] |
8,882,040 | https://en.wikipedia.org/wiki/International%20Forum%20Design | iF International Forum Design GmbH (iF) is a Hanover-based organization providing design-related services.
Foundation
International Forum Design was launched in 2001 as the operative business arm of design promotion company iF Industrie Forum Design Hannover e.V. (founded in 1953). International Forum Design and Industrie Forum Design are known internationally for awarding the annual iF product design awards.
Overview
Industrie Forum Design Hannover was established in 1953 as "Die gute Industrieform" ("Good Industrial Form") by Deutsche Messe AG (then known as Deutsche Messe- und Ausstellungs- AG); the Working Party on Industrial Design within the Federation of German Industries (BDI); and other design corporations. It is located in the Hanover exhibition center and was founded to promote industrial goods by organizing and promoting exhibitions. The company held its first exhibition in 1953, and has awarded the iF design awards annually since 1954. In 2001, managing director Ralph Wiegmann launched International Forum Design to oversee iF's business operations.
References
External links
International Forum Design website
Industrie Forum Design Hannover website
Design companies of Germany
Industrial design firms
Companies based in Hanover | International Forum Design | [
"Engineering"
] | 238 | [
"Design stubs",
"Design"
] |
8,883,686 | https://en.wikipedia.org/wiki/Calmurid | Calmurid was the name of a skin cream manufactured by Galderma (now discontinued due to safety reasons). Calmurid Cream contained the active ingredients lactic acid and urea, whereas Calmurid HC contained an additional ingredient, the mild corticosteroid hydrocortisone.
Owing to lactic acid's keratolytic properties (to break down hard skin cells) and urea's hydrating properties, Calmurid was used primarily in the treatment of dry, scaly skin. Ichthyosis and general dermatitis in the absence of inflammation are some of its indications.
When the extra steroid component is added (as in Calmurid HC), it was used to treat dry, scaly skin that is accompanied by inflammation of the skin. This may include various forms of eczema. The presence of a corticosteroid, however, means that the cream needed to be used sparingly and only for the shortest time period due to possible side effects that could occur due to systemic absorption of the steroid.
Composition: Urea 100Β mg/g and lactic acid 50Β mg/g in an emulsified base containing betaine monohydrate, glyceryl monostearate, diethanolamine cetylphosphate complex, hard fat, cholesterol, sodium chloride, purified water.
References
Skin care | Calmurid | [
"Chemistry"
] | 287 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
8,884,051 | https://en.wikipedia.org/wiki/Dirty%20drug | In pharmacology, a dirty drug is an informal term for drugs that may bind to many different molecular targets or receptors in the body, and so tend to have a wide range of effects and possibly adverse drug reactions. Today, pharmaceutical companies try to make new drugs as selective as possible to minimise binding to antitargets and hence reduce the occurrence of side effects and risk of adverse reactions.
Examples of compounds often cited as "dirty drugs" include tramadol, chlorpromazine, olanzapine, dextromethorphan, ibogaine, and ethanol, all of which bind to multiple receptors or influence multiple receptor systems. There may be instances of advantages to drugs that exhibit multi-receptor activity such as the anti-addictive drug ibogaine that acts within a broad range of neurohormonal systems where activity is also exhibited by drugs commonly associated with addiction including opioids, nicotine, and alcohol. Similarly chlorpromazine is primarily used as an antipsychotic, but its strong serotonin receptor blocking effects make it useful for treating serotonergic crisis such as serotonin syndrome. Dextromethorphan for its part is widely used as a cough medication, but its other actions have led to trials for several conditions such as its use as an adjunct to analgesia, and a potential anti-addictive drug, as well as its occasional recreational use as a dissociative.
Kanamycin is an aminoglycoside antibiotic which induces deafness through blockage of the outer hair cells of the cochlea; yet it has many other effects, weakening for instance the collagen and DNA biosynthesis. It acts by inhibiting the synthesis of proteins in susceptible organisms. Kanamycin requires close clinical supervision because of its potential toxicity and adverse side effects to the auditory and vestibular branches of the eighth cranial nerve and to the renal tubules.
Clozapine and latrepirdine are examples of drugs used in the treatment of CNS disorders that have a superior efficacy precisely because of their "multifarious" broadspectrum mode of activity. Likewise, in cancer chemotherapeutics, it has been recognized that drugs active at more than one target have a higher probability of being efficacious.
The anti-histamine and anti-cholinergic effects of atypical and low potency typical antipsychotics, such as the aforementioned clozapine and chlorpromazine, can also mediate against potentially distressing movement disorders such as extrapyramidal symptoms and akathisia associated with dopamine antagonism. In fact, clozapine may even help treat movement problems associated with Parkinson's disease.
Examples of "promiscuous" cancer drugs include: Sutent, Sorafenib, Zactima, and AG-013736.
In the field of drugs used to treat depression, the nonselective MAOIs and the TCAs are sometimes believed to have an efficacy that is superior to the SSRIs. SSRIs are usually nevertheless picked as the first-line choice of agent and not the (less-selective) MAOIs and TCAs for several reasons. Firstly, SSRIs are safer in overdose than TCAs. Secondly, MAOIs can cause serious side effects when mixed with certain foods, including life-threatening hypertensive crisis. MAOIs and TCAs generally have more side effects than SSRIs. TCAs in particular have anticholinergic side effects such as constipation and blurred vision, whereas SSRIs have fewer anticholinergic side effects.
References
Drug discovery
Pharmacodynamics | Dirty drug | [
"Chemistry",
"Biology"
] | 759 | [
"Pharmacology",
"Life sciences industry",
"Drug discovery",
"Pharmacodynamics",
"Medicinal chemistry"
] |
8,884,213 | https://en.wikipedia.org/wiki/ABCB5 | ATP-binding cassette sub-family B member 5 also known as P-glycoprotein ABCB5 is a plasma membrane-spanning protein that in humans is encoded by the ABCB5 gene. ABCB5 is an ABC transporter and P-glycoprotein family member principally expressed in physiological skin and human malignant melanoma.
Clinical significance
ABCB5 has been suggested to regulate skin progenitor cell fusion and mediate chemotherapeutic drug resistance in stem-like tumor cell subpopulations in human malignant melanoma, colorectal cancer, and malignant pleural mesothelioma. It is commonly over-expressed on circulating melanoma tumour cells. Furthermore, the ABCB5+ melanoma- initiating cells were demonstrated to express FLT1 (VEGFR1) receptor tyrosine kinase which was functionally required for efficient xenograft tumor formation, as demonstrated by shRNA knockdown experiments.
In colorectal cancer, ABCB5 was shown to act as a mediator of 5-FU patient chemoresistance, and had a further direct role in tumorigenesis shown by shRNA-mediated colorectal cancer cell-line ABCB5 knockdowns that impeded tumorigenesis in human-to-mouse xenografts. It has been shown that in some highly aggressive tumors, such as mesothelioma and melanoma, ABCB5 contributes to multi-drug chemotherapy resistance, and tumor growth, controlling a proinflammatory signaling circuit utilizing TLR4, IL-1Ξ², IL8 and CXCR1 signaling involving reciprocal paracrine interactions between the cancer stem cells and tumor bulk population (in a rheostat manner termed "cancer stem cell rheostasis"). ABCB5 was shown to maintain the slow-cycling melanoma stem cells using this cytokine signaling loop, which became more differentiated upon ABCB5 interference (e.g. WFDC1 melanocyte differentiation marker increased, cancer cells were faster growing in vitro, tumors were more pigmented), or CXCR1 blockade (slow-cycling ABCB5+ cells entered the cell-cycle).
In normal physiology, ABCB5 is a functional marker for adult limbal stem cells of the cornea. ABCB5+ cells could regrow a human cornea on a mouse with limbal stem cell deficiency (LSCD - a blindness disease of the corneal limbus) while ABCB5- cells could not, indicating a therapeutic potential for treating some types of blindness. ABCB5 was further shown to be anti-apoptotic in these adult stem cells.
References
Further reading
External links
Tumor markers | ABCB5 | [
"Chemistry",
"Biology"
] | 573 | [
"Chemical pathology",
"Tumor markers",
"Biomarkers"
] |
8,884,236 | https://en.wikipedia.org/wiki/The%20Revealer | The Revealer: A Review of Religion and Media is an online magazine published by the Center for Religion and Media at New York University. The Revealer publishes ten issues per year and features articles that explore religion and its many roles in society, politics, the media, and in people's lives.
History
NYU Journalism professor Jay Rosen developed the idea for The Revealer as a project for NYU's Center for Religion and Media, one of ten Centers of Excellence initially funded by The Pew Charitable Trusts and that Angela Zito and Faye Ginsburg founded in 2003. Jeff Sharlet and Kathryn Joyce created The Revealers website in 2003. Sharlet served as editor of the publication for five years before becoming a bestselling author with his book The Family: The Secret Fundamentalism at the Heart of American Power. In 2010, Ann Neumann assumed the position of editor, a title she kept until 2013. Kali Handelman was editor from 2013 to 2019, and Brett Krutzsch became editor in 2019.
With articles written for a broad audience, The Revealer features original articles by scholars, journalists, and freelance writers that explore how religion shapes, and is shaped by, race, sexuality, gender, politics, history, and culture. The online magazine publishes articles in many forms, including feature essays with original research and on-the-ground reporting, first person narratives, opinion pieces, interviews, photo-essays, and reviews of books, film, and television.
Current Publication
Since 2013, The Revealer has published ten issues a year, with a new issue coming out every month except January and August. Each issue covers a wide range of topics related to religion, with the exception of yearly "special issues" that focus on a single topic. A special issue in 2024 explored "The Threat of Christian Nationalism," one in 2022 explored "Trans Lives and Religion," and a special issue in 2020 explored "Religion and Sex Abuse."
In 2020, the magazine launched the Revealer Podcast. Since then, the Revealer podcast releases eleven episodes a year. In 2021, the Religion News Association named it a finalist for best religion podcast.
In 2021 and 2023, the Religion News Association awarded The Revealer with "Excellence in Magazine Overall Religion Coverage," the organization's highest prize for a print or online religion magazine.
See also
Reveal (disambiguation)
References
External links
American religious websites | The Revealer | [
"Technology"
] | 487 | [
"Computing stubs",
"World Wide Web stubs"
] |
8,884,500 | https://en.wikipedia.org/wiki/E%20%28PC%20DOS%29 | E is the text editor which was made part of PC DOS with version 6.1 in June 1993, in February 1995 with version 7 and later with PC DOS 2000. In version 6.1, IBM dropped QBASIC, which, in its edit mode, was also the system text editor. It was necessary to provide some sort of editor, so IBM chose to adapt and substantially extend its OS/2 System Editor (1986), a minimally functional member of the E family of Editors. The DOS version is extended with a wide array of functions that are usually associated with more functional versions of the E editor family (see below). In version 7, IBM added the REXX language to DOS, restoring programmability to the basic box. IBM also provided E with OS/2.
Features
The features include (for PC DOS 7):
online help
edit large text files
draw boxes around text
mouse and menu support
record and play keystroke macros
change case within a marked area
access multiple files in multiple panes
syntax-directed editing of C and REXX
add and multiply numbers in a marked area
locate and make a change globally within a file
select text and move, copy, overlay, or delete it
copy and move text from one file into another file
E for PC DOS consists of five files:
E.EXE -- the executable program itself, (v3.13 in PC DOS 7)
E.EX -- pre-compiled profile for E's behavior
E.INI -- text file allowing modification of a few E.EX defaults (Not in v 3.12 (dos 6))
EHELP.HLP -- text file used for E's F1 key help in Browse (read-only) mode
BROWSE.COM -- loads a file into E in read-only mode. (Not in v 3.12 (dos 6))
Since no tool was provided for building other profiles besides the supplied E.EX, PC DOS users have limited access to the full extensibility offered by the version 3 of E (e3) available to IBM programmers themselves. Still, it is a powerful implementation, with many features supporting the needs of general programmers.
For PC DOS owners who have moved on to other operating systems, E can be run with the use of a DOS emulator (e.g. DOSBox) or with DOS virtualization software (e.g. DOSEMU or NTVDM). E runs quite successfully under the Windows NT 32-bit DOS prompt, for example.
To run the E Editor under OS/2, you must swap the first two directories in PATH statement of AUTOEXEC.BAT. Put the E files in \OS2\MDOS directory. E v3.12 was also supplied in OS/2 PPC edition.
E family
The history of the PC DOS version of E begins with Personal Editor, a key configurable editor that enabled limited programming using a GML-like language. Personal Editor was initially released in 1982 and became an IBM product not long after.
Limitations in Personal Editor led to the development and release in 1984 of the E editor, a much faster editor that supported very long files and included a substantially enhanced user interface. E2, released in 1985, provided enhanced programmability using a REXX-like language. Its UI programmability was designed so flexibly that it was used to develop user interface prototypes for other kinds of software, including Word Processors and Survey software. Subsequent versions, including E3, EOS2, and EPM, provided a wide range of other enhancements. The OS/2 System Editor was developed by the E programming team at the request of the OS/2 Development team. It was designed to be a fast and highly functional text editor with a minimal number of features and no configurability. EPM was later released as the OS/2 Enhanced Editor. The popular SlickEdit shares a common heritage, having been written by the original developer of E3. Other versions of E family editors have been released with IBM programming products. There are several acknowledged E editor family clones, including X2, which both reproduces the Rexx-like EI programming language used in E2 and later versions of E and acknowledges its debt in its documentation.
See also
MS-DOS Editor
References
DOS commands
OS/2
Text editors
Rexx | E (PC DOS) | [
"Technology"
] | 897 | [
"DOS commands",
"Computing platforms",
"OS/2",
"Computing commands"
] |
8,884,790 | https://en.wikipedia.org/wiki/Cutler%27s%20bar%20notation | In mathematics, Cutler's bar notation is a notation system for large numbers, introduced by Mark Cutler in 2004. The idea is based on iterated exponentiation in much the same way that exponentiation is iterated multiplication.
Introduction
A regular exponential can be expressed as such:
However, these expressions become arbitrarily large when dealing with systems such as Knuth's up-arrow notation. Take the following:
Cutler's bar notation shifts these exponentials counterclockwise, forming . A bar is placed above the variable to denote this change. As such:
This system becomes effective with multiple exponents, when regular denotation becomes too cumbersome.
At any time, this can be further shortened by rotating the exponential counterclockwise once more.
The same pattern could be iterated a fourth time, becoming . For this reason, it is sometimes referred to as Cutler's circular notation.
Advantages and drawbacks
The Cutler bar notation can be used to easily express other notation systems in exponent form. It also allows for a flexible summarization of multiple copies of the same exponents, where any number of stacked exponents can be shifted counterclockwise and shortened to a single variable. The bar notation also allows for fairly rapid composure of very large numbers. For instance, the number would contain more than a googolplex digits, while remaining fairly simple to write with and remember.
However, the system reaches a problem when dealing with different exponents in a single expression. For instance, the expression could not be summarized in bar notation. Additionally, the exponent can only be shifted thrice before it returns to its original position, making a five degree shift indistinguishable from a one degree shift. Some have suggested using a double and triple bar in subsequent rotations, though this presents problems when dealing with ten- and twenty-degree shifts.
Other equivalent notations for the same operations already exist without being limited to a fixed number of recursions, notably Knuth's up-arrow notation and hyperoperation notation.
See also
Mathematical notation
References
Mark Cutler, Physical Infinity, 2004
Daniel Geisler, tetration.org
R. Knobel. "Exponentials Reiterated." American Mathematical Monthly 88, (1981)
Mathematical notation
Large numbers | Cutler's bar notation | [
"Mathematics"
] | 470 | [
"Mathematical objects",
"Numbers",
"nan",
"Large numbers"
] |
8,884,816 | https://en.wikipedia.org/wiki/CC%E2%80%93PP%20game | The Commonize CostsβPrivatize Profits Game (or CCβPP Game) is a concept developed by the ecologist Garrett Hardin to describe a "game" (in the game theory sense) widely played in matters of resource allocation. The concept is Hardin's interpretation of the closely related phenomenon known as the tragedy of the commons, and is referred to in political discourse as "privatizing profits and socializing losses."
The CCβPP Game originally appeared in Hardin's book titled Filters against Folly: How To Survive Despite Economists, Ecologists, and the Merely Eloquent which was published in 1986.
Players of the CCβPP Game aim to commonize the costs (or externalities) generated by their activities across the wider community, while privatizing all profits (financial or otherwise) to themselves. The individual does not broadcast that they are playing the game in order to continue profiting.
Hardin related the CCβPP Game to ecological problems such mining, groundwater overdraft, cattle ranching and other actions that cause the depletion of natural resources or an increase in pollution.
Tragedy of the Commons and the CCβPP Game
The CCβPP Game is used to explain how individuals utilize public goods, specifically scarce natural resources. These goods include resources such as clean air, rivers, forests and groundwater. These are public goods because they are both non-excludable and non-rival. It is very difficult to assign property rights to public goods, which results in many people using the resource and the resource's subsequent depletion or the tragedy of the commons.
Hardin uses the original conception of the commons as a "village pasture used for grazing sheep or cattle in preindustrial England." The pasture was a public space for any villager to use to graze their livestock. Villagers gained profit from each additional animal on the pasture, but did not have to pay the costs of the animals depleting the grass. The village as a whole took on the cost of overgrazing the pasture. This represented the CCβPP Game for Hardin in which the incentive to create individual profit was greater than the cost of overgrazing the field since it was spread out between many individuals.
In a more modern example of the CCβPP Game, Hardin attributes the desertification of the Sahel desert to "unmanaged access and overuse."
John D. Aram summarized the tragedy of the commons and the CCβPP Game stating, "Tragic macro effects result from a structure of micro incentives that allows unmanaged access to a fixed resource."
Game Theory and the CCβPP Game
The CCβPP Game is an example of a non-cooperative equilibrium or Nash Equilibrium in which the parties in the game do not cooperate and are incentivized to deplete natural resources, resulting in an inefficient outcome.
The CCβPP Game refers to the market for a scarce natural resource, for example groundwater. Groundwater is scarce because it can be extracted from the ground at a much higher rate than it can be replenished naturally. In addition, clean groundwater in many areas is limited. Groundwater is a natural resource that can be difficult to assign property rights to and is needed by all individuals.
Private firms as well as everyday consumers will extract groundwater for their own use. Private firms gain profits from using the water to produce a good or directly selling the water. Individual consumers gain utility or satisfaction from drinking the water or using it in their homes. Both the private firm and the individual have an incentive to take water from the ground and receive a gain in utility from taking that water (privatized profits). The water supply is diminished, resulting in a tragedy of the commons and a loss of utility for everyone that uses the groundwater (communized costs). Since an individual user does not have to pay for the cost of water depletion, but is still gaining the utility or profit from using the water, the individual will continue to use the water. Every individual will come to this same conclusion and the natural resource will be depleted.
This can be seen in a pay-off matrix. Where there are two individuals making separate choices to defect by privatizing benefits and commonizing costs, or to cooperate and refrain from personal gain in order to preserve a resource. If Individual A decides to preserve water while Individual B does not then Individual A will only receive $20 while Individual B gains $80. This is true vice versa if Individual B decides to preserve water and Individual A decides to extract. Both individuals have an incentive to defect and extract water to gain $50, so as rational consumers they will extract water. However, if neither party extracted water then they would actually gain $50 more in profit. This is a case of the Prisoner's Dilemma. However, unlike the Prisoner's Dilemma that only has two people, CCβPP Game is an aggregate of many individuals, making it harder to see the effects of a single person's decisions.
Real Life Examples
Fisheries
Fisheries are a prime example of the CCβPP Game. Companies gain a profit for every fish that they catch and are incentivized to continue catching fish. However, their overfishing depletes the amount of fish in the ocean, hurting the environment and other individuals. All individuals pay for the cost of a decrease in the amount of fish.
Mining
Mining companies participate in the CCβPP Game by depleting their worker's health. Hardin argues that the owners of mining companies profit from their workers, while workers suffer the negative health effects of mining such as respiratory damage, chronic lead poisoning, mercury poisoning, black lung disease, and poisoning by radon gas in uranium mines. Hardin states, "Until the development of nationalized schemes of compensation in the twentieth century the costs of deteriorated health were "paid" by the miner himself, partly in medical bills but even more in reduced capacity to work and enjoy life."
Intangible Assets
Hardin also included "intangible assets" such as βworker safety, stabilizing the cost of healthcare, and economic efficiency" as instances of tragedy of the commons. These assets can also deteriorate if individuals choose to privatize benefits and communize costs.
Policy Applications
Hardin proposed several solutions to the CCβPP Game in his books and essays.
In Hardin's early works, he expressed his belief that they only way to protect natural resources was by limiting individual's freedoms. He stated that preserving the commons would only be possible by βmutual coercion, mutually agreed upon.β Today, this would be considered command and control regulation. Hardin believed that individuals needed regulation or systems in place to force them to stop depleting resources. He rejected the option of people volunteering to not ruin common goods because of individual's lack of will power and lack of incentives to limit themselves. He believed that voluntary self-restraint was not a solution to avoiding the tragedy of the commons.
However, later in his career, Hardin argued that a strict individual responsibility could preserve the commons. He described systems of accountability for policy makers in order to preserve the commons for their constituents. This puts the responsibility for preserving the commons onto the political system.
Ideally Hardin wanted all costs and benefits to be privatized. John D. Aram argues that Hardin would be in favor of a flat tax structure and elimination of public subsidies.
See also
Common good (economics)
Common-pool resource
Externality
Tragedy of the Commons
Nash Equilibrium
References
External links
Who benefits, who pays?, an extract from Filters Against Folly
Natural resource management
Game theory game classes
Market failure | CCβPP game | [
"Mathematics"
] | 1,544 | [
"Game theory game classes",
"Game theory"
] |
8,884,972 | https://en.wikipedia.org/wiki/Kirchhoff%20equations | In fluid dynamics, the Kirchhoff equations, named after Gustav Kirchhoff, describe the motion of a rigid body in an ideal fluid.
where and are the angular and linear velocity vectors at the point , respectively; is the moment of inertia tensor, is the body's mass; is
a unit normal vector to the surface of the body at the point ;
is a pressure at this point; and are the hydrodynamic
torque and force acting on the body, respectively;
and likewise denote all other torques and forces acting on the
body. The integration is performed over the fluid-exposed portion of the
body's surface.
If the body is completely submerged body in an infinitely large volume of irrotational, incompressible, inviscid fluid, that is at rest at infinity, then the vectors and can be found via explicit integration, and the dynamics of the body is described by the Kirchhoff β Clebsch equations:
Their first integrals read
Further integration produces explicit expressions for position and velocities.
References
Kirchhoff G. R. Vorlesungen ueber Mathematische Physik, Mechanik. Lecture 19. Leipzig: Teubner. 1877.
Lamb, H., Hydrodynamics. Sixth Edition Cambridge (UK): Cambridge University Press. 1932.
Mechanics
Classical mechanics
Rigid bodies
Gustav Kirchhoff | Kirchhoff equations | [
"Physics",
"Chemistry",
"Engineering"
] | 285 | [
"Classical mechanics",
"Mechanics",
"Mechanical engineering",
"Fluid dynamics stubs",
"Fluid dynamics"
] |
8,885,224 | https://en.wikipedia.org/wiki/Oasification | In hydrology, oasification is the antonym to desertification by soil erosion. This technique has limited application and is normally considered for much smaller areas than those threatened by desertification.
Oasification is also a developing direction of environmental engineering.
To help the oasification process, engineers aim to develop a thriving dense woody plant cover to redress the hydrological, edaphic and botanical degradation affecting a slope. This is done through appropriate soil preparation and the introduction of suitable plant species. It is also necessary to make adequate water harvesting systemsβideally taking advantage of the degradation process of the slope, collecting runoff water in ponds around the sites to be forested.
The term "oasification" was coined in 1999 by AndrΓ©s MartΓnez de Azagra Paredes, PhD Forest Engineer and professor on Hydraulics and Forest Hydrology at E.T.S. of Agroforestry Engineering in Palencia, University of Valladolid, Spain.
In oasification, soil and nutrient harvesting are regarded as fundamental component parts in the reclamation process of a degraded slope. Besides harvesting water, oasification preserves and accumulates soil and nutrients, helping to control water erosionβa common problem in dry climates. Ludwig et al. (1997) reported about sloping areas under semiarid conditions in Australia where the landscape is naturally divided into source and sink zones (surface runoff and run-on areas), which are sometimes reclaimed by plant species through retention of water soil and litter.
A common approach is the planting of various common horticulturally significant trees, which "are adapted to dry environments...these plants act as windbreaks and the extensive root network binds the soil thus reducing water erosion especially at the beginning of the rainy season when soil cover is at its lowest. Deciduous activity returns large amounts of organic matter to the soil in the form of leaf material which in tum support more vegetation biomass, and hence more soil cover and consequently erosion control. Eventually, ecosystems are reclaimed and desertification controlled." Some of the trees deployed in this way include olive, cashew, date palm, fig, guava, mango, tamarind, pomegranate, papaya, lasoda, and jojoba. Drought-tolerant legumes that provide additional biomass and fix nitrogen include green gram (Phaseolus aureus), black gram (Vigna mungo), chickpea (Cicer arictinum), cowpea (Vigna unguiculata), and lentil (Lens esculenta).
Not only plants can effectively prevent land degradation, but microorganisms are also an effective biological measure to prevent land desertification. Microorganisms can greatly help the artificially cultivated sand control plants to survive in the oasis, thus reducing the waste of resources during recultivation. βMicrobial control of land desertification includes organisms such as mosses, lichens,Β cyanobacteria and slime molds to restore soil nutrients,Β The use of engineered biocrustβforming cyanobacteria with these traits (vs. nonβengineered) has the effect of restoringΒ soil fertility. potential to further increase soil fertility and to reduce soil erosion,Β thus accelerating the recovery of degraded drylands. (Maestre et al., 2017).β
There are drawbacks to overbuilding oases. Water use in oases is often influenced by plants,Β climate and human activities. This means that managers not only need to maintain a balance between direct human andΒ natural water use, but also find ways to preserve water near oases. If there is no way to distribute it properly,Β it will cause serious consequences.
References
MartΓnez de Azagra Paredes, A. (1999): El modelo hidrolΓ³gico MODIPΓ. Montes, 55: 77 β 82
Ludwig, J.; Tongway, D.; Freudenberger, D.; Noble, J. y Hodgkinson, K. (1997): Landscape ecology. Function and management. CSIRO. Collingwood (Australia)
Xue, J., Gui, D., Lei, J., Sun, H., Zeng, F., Mao, D., Jin, Q., & Liu, Y. (2019). Oasification: An unable evasive process in fighting against desertification for the sustainable development of arid and semiarid regions of China. CATENA, 179, 197-209.https://doi.org/10.1016/j.catena.2019.03.029
Maestre, F. T., SolΓ©, R., & Singh, B. K. (2017). Microbial biotechnology as a tool to restore degraded drylands. Microbial biotechnology, 10(5), 1250β1253. https://doi.org/10.1111/1751-7915.12832
MartΓnez-Valderrama J, Gui D, Ahmed Z. Oasification and Desertification under the Framework of Land Degradation Neutrality. Environmental Sciences Proceedings. 2023; 25(1):94. https://doi.org/10.3390/ECWS-7-14238
External links
Oasification web-site
Aquatic ecology
Desert greening
Hydrology
Permaculture | Oasification | [
"Chemistry",
"Engineering",
"Biology",
"Environmental_science"
] | 1,090 | [
"Aquatic ecology",
"Hydrology",
"Ecosystems",
"Environmental engineering"
] |
8,885,345 | https://en.wikipedia.org/wiki/Concoction | Concoction is the process of preparing a medicine, food or other substance out of many ingredients, and also the result of such a process.
Historically, the word referred to digestion, as conceived by Aristotle who theorized that this was the result of the heat of the body acting upon the material, causing it to mature and ripen.
The term later came to refer to liquid broths, cocktails and potions which are similarly formed by heating or blending multiple ingredients. Concoctions that were made in apothecaries, or as used in traditional medicine, , rather than nourishment or pleasure (in which case it would be cookery or cuisine). In a medical context, such concoctions have largely been superseded by modern medicine.
In modern usage, the term may refer more loosely to any mixture of various ingredients, including soups and cocktails, or abstract ingredients, such as design elements in architecture or fashion, or an elaborate excuse.
In such uses, the term often retains a connotation that the mixture is strange, unusual, or elaborate.
References
Chemical mixtures
History of pharmacy
Biologically based therapies
Traditional medicine | Concoction | [
"Chemistry"
] | 236 | [
"Chemical mixtures",
"nan"
] |
8,885,941 | https://en.wikipedia.org/wiki/Core-and-veneer | Core-and-veneer, brick and rubble, wall and rubble, ashlar and rubble, and emplekton all refer to a building technique where two parallel walls are constructed and the core between them is filled with rubble or other infill, creating one thick wall. Originally, and in later poorly constructed walls, the rubble was not consolidated. Later, mortar and cement were used to consolidate the core rubble and produce sturdier construction.
Modern masonry still uses core and veneer walls; however, the core is now generally concrete block instead of rubble, and moisture barriers are included. Often such walls end up as cavity walls by the inclusion of space between the external veneer and the core in order to provide for moisture and thermal control.
History
Greeks and Phoenicians
Both the early Phoenicians and Greeks used rubble-filled masonry walls. The word emplekton was borrowed from Greek αΌΞΌΟλΡκΟΞΏΞ½ and originally meant "rubble" but came to apply to the construction technique as well.
Romans
The Romans started with basic emplekton masonry walls, but developed the technique further using temporary walls (forms) that were removed after the cemented rubble (concrete) had cured. This technique was called opus caementicium, and eventually led to modern ferroconcrete construction.
India
The buildings of the Taj Mahal are constructed with walls of brick and rubble inner cores faced with either marble or sandstone locked together with iron dowels and clamps. Some of the walls of the mausoleum are several metres thick.
Ancestral Puebloans
In the large complexes at Chaco Canyon, the Ancestral Puebloans used the wall and rubble technique, with walls of carefully shaped sandstone. The Ancestral Puebloans used mud as their mortar, both with the veneer and to consolidate the core. This core and veneer technique was also used at other Ancestral Puebloans sites outside of Chaco Canyon. Later pueblos used mud bricks (adobe) for the veneer.
Mayan
In the Puuc region, and as far south as at least Tikal, the Mayans developed core-and-veneer walls to the point where, by the classic period, they were filled with concrete.
Problems
Traditional core-and-veneer walls suffered from moisture migration and thermal expansion and contraction. They had a low tensile strength, hence a poor resistance to twisting or stretching. Tensile strength was increased by increasing the width of the walls or by providing masonry "piers" (vertical columns or ribs), either inside the wall or as additional exterior support.
See also
Bungaroosh
Cavity wall
Notes
External links
shows construction and cross-section of core-and-veneer wall
showing cross-section of a core-and-veneer wall.
Masonry
Construction
Types of wall | Core-and-veneer | [
"Engineering"
] | 565 | [
"Structural engineering",
"Types of wall",
"Construction",
"Masonry"
] |
8,886,686 | https://en.wikipedia.org/wiki/Jewellery%20design | Jewellery design is the art or profession of designing and creating jewellery. It is one of civilization's earliest forms of decoration, dating back at least 7,000 years to the oldest-known human societies in Indus Valley Civilization, Mesopotamia, and Egypt. The art has taken many forms throughout the centuries, from the simple beadwork of ancient times to the sophisticated metalworking and gem-cutting known in the modern day.
Before an article of jewellery is created, design concepts are rendered followed by detailed technical drawings generated by a jewellery designer, a professional who is trained in the architectural and functional knowledge of materials, fabrication techniques, composition, wearability, and market trends.
Traditional hand-drawing and drafting methods are still utilized in designing jewellery, particularly at the conceptual stage. However, a shift is taking place to computer-aided design programs. Whereas the traditionally hand-illustrated jewel is typically translated into wax or metal directly by a skilled craftsman, a CAD model is generally used as the basis for a CNC cut or 3D printed 'wax' pattern to be used in the rubber moulding or lost wax casting processes.
Once conceptual/ideation is complete, the design is rendered and fabricated using the necessary materials for proper adaptation to the function of the object. For example, 24K gold was used in ancient jewellery design because it was more accessible than silver as source material. Before the 1st century, many civilizations also incorporated beads into jewellery. Once the discovery of gemstones and gem cutting became more readily available, the art of jewellery ornamentation and design shifted. The earliest documented gemstone cut was done by Theophilus Presbyter (c. 1070β1125), who practised and developed many applied arts and was a known goldsmith. Later, during the 14th century, medieval lapidary technology evolved to include cabochons and cameos.
Early jewellery design commissions were often constituted by nobility or the church to honour an event or as wearable ornamentation. Within the structure of early methods, enameling and repoussΓ© became standard methods for creating ornamental wares to demonstrate wealth, position, or power. These early techniques created a specific complex design element that later would forge the Baroque movement in jewellery design.
Traditionally, jewels were seen as sacred and precious; however, since the 1900s, jewellery has started to be objectified. Additionally, no one trend can be seen in the history of jewellery design for this period. Throughout the 20th-century jewellery design underwent drastic and continual style changes: Art Nouveau (1900β1918), Art Deco (1919β1929), International Style & organicism (1929β1946), New Look & Pop (1947β1967), Globalization, Materialism, and Minimalism. Jewellery design trends are highly affected by the economic and social states of the time. The boundaries of styles and trends tend to blur together and the clear stylistic divisions of the past are harder to see during the 20th century.
References
Design occupations
Jewellery
Jewellery designers | Jewellery design | [
"Engineering"
] | 599 | [
"Design occupations",
"Design"
] |
5,648,485 | https://en.wikipedia.org/wiki/List%20of%20species%20on%20Caroline%20Island | Species recorded on Caroline Island, one of the Line Islands in the south-central Pacific Ocean:
Flora
Trees
Calophyllum
Cocos nucifera
Cordia subcordata
Hibiscus tiliaceus
Morinda citrifolia
Pandanus tectorius
Pisonia grandis
Thespesia populnea
Shrubs
Heliotropium foertherianum
Scaevola taccada
Suriana maritima
Ximenia americana
Herbs
Achyranthes canscens
Boerhavia repens
Heliotropium anomalum
Ipomoea macrantha
Ipomoea violacea
Laportea ruderalis
Lepidium bidentatum
Lepturus repens
Lygodium microphyllum
Phyllanthus amarus
Phymatosorus scolopendria
Portulaca lutea
Psilotum nudum
Sida fallax
Tacca leontopetaloides
Tribulus cistoides
Fauna
Nesting seabirds
Black noddy (Anous minutus)
Blue-grey noddy (Procelsterna cerulea) (Kepler)
Brown booby (Sula leucogaster)
Brown noddy (Anous stolidus)
Great frigatebird (Fregata minor)
Lesser frigatebird (Fregata ariel)
Masked booby (Sula dactylatra)
Red-footed booby (Sula sula)
Red-tailed tropicbird (Phaethon rubricauda) (Kepler)
Sooty tern (Onychoprion fuscata)
White tern (Gygis alba)
Other birds
Bristle-thighed curlew (Numenius tahitiensis)
Lesser golden-plover (Pluvialis dominica) (Kepler)
Long-tailed cuckoo (Eudynamis taitensis)
Pacific golden plover (Pluvialis fulva)
Reef heron (Egretta sacra) (Kepler)
Ruddy turnstone (Arenaria interpres) (Kepler)
Sanderling (Crocethia alba) (Kepler)
Short-eared owl (Asio flammeus ponapensis)
Wandering tattler (Tringa incana)
Lizards
Azure-tailed skink (Emoia cyanura) (Kepler)
Emoia impar (Kepler)
Moth skink (Lipinia noctua) (Kepler)
Mourning gecko (Lepidodactylus lugubris) (Kepler)
Polynesian gecko (Gehyra oceanica) (Kepler)
Snake-eyed skink (Cryptoblepharus poecilopleurus) (Kepler)
Mammals
Pacific bottlenose dolphin (Tursiops gilli) (Kepler)
Polynesian rat (Rattus exulans) (Kepler)
Turtles
Green sea turtle (Chelonia mydas)
Crabs
Coconut crab (Birgus largo)
Red spotted crab (Carpilius maculatus) (Kepler)
Scarlet crab (Cornobita perlatus) (Kepler)
Polychaetes
Calcareous tubeworm (Serpula tetratropia)
Notes
References
Species
Flora of Micronesia
Flora of the south-central Pacific
Lists of biota of Kiribati
Lists of plants
Lists of animals by location
Flora of the Oceanian realm
Fauna of the Oceanian realm
Caroline Island | List of species on Caroline Island | [
"Biology"
] | 674 | [
"Lists of biota",
"Lists of plants",
"Plants"
] |
5,648,829 | https://en.wikipedia.org/wiki/HBV%20hydrology%20model | The HBV hydrology model, or Hydrologiska ByrΓ₯ns Vattenbalansavdelning model, is a computer simulation used to analyze river discharge and water pollution. Developed originally for use in Scandinavia, this hydrological transport model has also been applied in a large number of catchments on most continents.
Discharge modelling
This is the major application of HBV, and has gone through much refinement. It comprises the following routines:
Snow routine
Soil moisture routine
Response function
Routing routine
The HBV model is a lumped (or semi-distributed) bucket-type (or also called 'conceptual') catchment model that has relatively few model parameters and minimal forcing input requirements, usually the daily temperature and the daily precipitation.
First, the snow is calculated after defining a threshold melting temperature (TT usually 0Β Β°C) and a parameter CMELT that reflects the equivalent melted snow for the difference of temperature. The result is divided into a surface runoff part and a part that enters the soil by infiltration.
Second, the soil moisture is calculated after defining an initial value and the field capacity (FC).
Third, the actual Evapotranspiration (ETPa) is calculated, first by using an external model (such as Penman-Montieth) for finding the potential ETP and then fitting the result to the temperatures and the permanent wilting point(PWP) of the catchment in question. A parameter C which reflects the increase in the ETP with the differences in temperatures (Actual Temperature and Monthly mean Temperature).
The model considers the catchment as two reservoirs (S1 and S2) connected by a percolation flow. The inflow to the first reservoir is calculated as the surface runoff, which is what remains from the initial precipitation after calculating the infiltration and the evapotranspiration.
The outflow from the first reservoir is divided into two separate flows (Q1 and Q2), where Q1 represents the fast flow which is triggered after a certain threshold L (defined by the user or by calibration) and Q2 represents the intermediate flow. A constant K1 is used to find the outflows as a function of the storage in S1.
The percolation rate depends on a constant Kd along with the storage in S1.
The outflow from the second reservoir is considered to be the groundwater flow (Q3), a function of a constant K2 and the storage in S2.
The total flow generated from a certain rain event is the sum of the 3 flows.
Calibration. The result of the model are later compared to the actual measured flow values and Nash-Sutcliffe parameter is used to calibrate the model by changing the different parameters. The model has 9 parameters in total: TT, Cmelt, FC, C, PWP, L, K1, K2, Kd. For a good calibration of the model it is better to use Monte-Carlo simulation or the GLUE method to properly define the parameters and the uncertainty in the model.
The model is fairly reliable but as usual the need of good input data is essential for good results. The sensitivity of the HBV model to parameter uncertainty has been explored revealing significant parameter interactions affecting calibration uniqueness, and some state dependence.
Applications. HBV has been used to simulate river discharge in many countries worldwide, including Brazil, China, Iran, Mozambique, Sweden, Switzerland and Zimbabwe. The HBV has also been used to simulate internal variables such as groundwater levels. The model has also been used for hydrological change detection studies and climate-change impact studies.
Versions. The HBV model exists in several versions. One version, which has been especially designed for education with a user-friendly graphical user interface, is HBV light. HBV emulation is available as a part of Raven hydrologic framework. Raven is an open-source robust and flexible hydrological modelling framework, designed for application to challenging hydrological problems in academia and practice. This fully object-oriented code provides complete flexibility in spatial discretization, interpolation, process representation, and forcing function generation.
Sediment and solute modelling
The HBV model can also simulate the riverine transport of sediment and dissolved solids. LidΓ©n simulated the transport of nitrogen, phosphorus and suspended sediment in Brazil, Estonia, Sweden and Zimbabwe.
See also
Hydrological transport model
Runoff model
References
External links
The HBV model at the Swedish Department of Climate (SMHI)
HBV light at the University of Zurich
HBV Matlab Code (lumped version)
HBV-EC pre- and post-processor "Green Kenue" free download at the Canadian Hydraulics Centre
HBV program in RS MINERVE at the CREALP (lumped version)
Computer-aided engineering software
Hydrology models | HBV hydrology model | [
"Biology",
"Environmental_science"
] | 991 | [
"Hydrology",
"Environmental modelling",
"Hydrology models",
"Biological models"
] |
5,648,968 | https://en.wikipedia.org/wiki/Luis%20von%20Ahn | Luis von Ahn (; born 19 August 1978) is a Guatemalan-American entrepreneur, software developer, and consulting professor in the Computer Science Department at Carnegie Mellon University in Pittsburgh, Pennsylvania. He is known as one of the pioneers of crowdsourcing. He is the founder of the company reCAPTCHA, which was sold to Google in 2009, and the co-founder and CEO of Duolingo.
Early life and education
Luis von Ahn was born and raised in Guatemala City. He is of German-Jewish and Guatemalan descent. His mother was one of the first women in Guatemala to complete medical school. She gave birth to von Ahn at age 42, and raised him as a single mother. He attended the American School of Guatemala, a private English-language school in Guatemala City, an experience he cites as a great privilege. When von Ahn was eight years old, his mother bought him a Commodore 64 computer, beginning his fascination with technology and computer science. When he applied to colleges in the United States, von Ahn had to spend more than $1,200 to fly to neighboring El Salvador to take the TOEFL. This experience left him with a negative impression of an "extractive" testing industry, ripe for disruption.
At age 18, von Ahn began studying at Duke University, where he received a Bachelor of Science (BS) in Mathematics, summa cum laude, in 2000. He later earned his PhD in Computer Science at Carnegie Mellon University in 2005.
In 2006, Von Ahn became a faculty member at Carnegie Mellon University's School of Computer Science.
Career and research
Von Ahn's early research was in the field of cryptography. With Nicholas J. Hopper and John Langford, he was the first to provide rigorous definitions of steganography and to prove that private-key steganography is possible.
In 2000, he did early pioneering work with Manuel Blum on CAPTCHAs, computer-generated tests that humans are routinely able to pass but that computers have not yet mastered. These devices are used by web sites to prevent automated programs, or bots, from perpetrating large-scale abuse, such as automatically registering for large numbers of accounts or purchasing huge numbers of tickets for resale by scalpers. CAPTCHAs brought von Ahn his first widespread fame among the general public due to their coverage in the New York Times and USA Today and on the Discovery Channel, NOVA scienceNOW, and other mainstream outlets.
Von Ahn's PhD thesis, completed in 2005, was the first publication to use the term "human computation" that he had coined, referring to methods that combine human brainpower with computers to solve problems that neither could solve alone. Von Ahn's PhD thesis is also the first work on Games With A Purpose, or GWAPs, which are games played by humans that produce useful computation as a side effect. The most famous example is the ESP Game, an online game in which two randomly paired people are simultaneously shown the same picture, with no way to communicate. Each then lists a number of words or phrases that describe the picture within a time limit, and are rewarded with points for a match. This match turns out to be an accurate description of the picture, and can be successfully used in a database for more accurate image search technology. The ESP Game was licensed by Google in the form of the Google Image Labeler, and is used to improve the accuracy of the Google Image Search. Von Ahn's games brought him further coverage in the mainstream media. His thesis won the Best Doctoral Dissertation Award from Carnegie Mellon University's School of Computer Science.
In July 2006, von Ahn gave a tech talk at Google on "Human Computation" (i.e., crowdsourcing) which was watched by over one million viewers.
In 2007, von Ahn invented reCAPTCHA, a new form of CAPTCHA that also helps digitize books. In reCAPTCHA, the images of words displayed to the user come directly from old books that are being digitized; they are words that optical character recognition could not identify and are sent to people throughout the web to be identified. ReCAPTCHA is currently in use by over 100,000 web sites and is transcribing over 40 million words per day.
In 2009, von Ahn and his graduate student Severin Hacker began to develop Duolingo, a language education platform. They founded a company of the same name, with von Ahn as chief executive officer and Hacker as chief technology officer. In November 2011, a private beta test of Duolingo was launched and the app was released to the public in June 2012. As of May 2020, Duolingo was valued at $1.5 billion. In a talk with NPR, von Ahn shared that Duolingo saw a spike in users during the COVID-19 pandemic. von Ahn has a chapter giving advice in Tim Ferriss' book Tools of Titans.
In May 2021 von Ahn joined the executive committee of Partnership for Central America, an entity bringing together a variety of businesses, academic organizations and nonprofit organizations "to advance economic opportunity, address urgent climate, education and health challenges, and promote long-term investments and workforce capability building to support a vision of hope for Central America". The Partnership for Central America was presented in the context of the United States' Vice President Kamala Harris's "call to action" to address irregular migration from Central America to the United States by "deepening investment in the Northern Triangle" (a term coined to refer to Guatemala, El Salvador and Honduras).
Awards and honors
His research on CAPTCHAs and human computation has earned him international recognition and numerous honors. He was awarded a MacArthur Fellowship in 2006, the David and Lucile Packard Foundation Fellowship in 2009, a Sloan Fellowship in 2009, and a Microsoft New Faculty Fellowship in 2007, and the Presidential Early Career Award for Scientists and Engineers in 2012. He has also been named one of the 50 Best Brains in Science by Discover, and has made it to many recognition lists that include Popular Science's Brilliant 10, Silicon.com's 50 Most Influential People in Technology, MIT Technology Review'''s TR35: Young Innovators Under 35, and Fast Company's 100 Most Innovative People in Business.Siglo Veintiuno'', one of the biggest newspapers in Guatemala, chose him as the person of the year in 2009. In 2011, Foreign Policy Magazine in Spanish named him the most influential intellectual of Latin America and Spain.
In 2011, he was awarded the A. Nico Habermann development chair in computer science, which is awarded every three years to a junior faculty member of unusual promise in the School of Computer Science.
In 2017, he was awarded the Distinguished Leadership Award for Innovation and Social Impact by the Inter-American Dialogue.
In 2018, von Ahn was awarded the Lemelson-MIT prize for his "dedication to improving the world through technology."
In 2021, von Ahn was named by Carnegie Corporation of New York as an honoree of the Great Immigrants Award.
Teaching
Von Ahn has used a number of unusual techniques in his teaching, which have won him multiple teaching awards at Carnegie Mellon University. In the fall of 2008, he began teaching a new course at Carnegie Mellon entitled "Science of the Web". A combination of graph theory and social science, the course covers topics from network and game theory to auction theory.
In his 2023 Ted Talk, he emphasised on the importance of making learning as fun as playing video games or using social media apps, by using similar features such as streak, leaderboard, etc.
Philanthropy
In 2021, von Ahn established the ILVA Foundation. The focus of the Foundation is to support Guatemalans, especially women and girls, through financial support to local community leaders and nonprofit organizations. According to the foundation website, in 2022 the Luis von Ahn Foundation will give US$3 million to various organizations that focus on "women's and girls equality, conservation of the environment, and democracy and youth participation."
References
www.networthmama.com in 2024 and Career Highlights
External links
Google Tech Talk on human computation by Luis von Ahn
Profile: Luis von Ahn NOVA scienceNOW aired 2009-06-30
ILVA Foundation Website
Guatemalan computer scientists
1978 births
Living people
MacArthur Fellows
Carnegie Mellon University alumni
Duke University Trinity College of Arts and Sciences alumni
Duolingo
Carnegie Mellon University faculty
Human-based computation
People from Guatemala City
Computer science educators
Guatemalan people of German descent
Guatemalan academics
Hispanic and Latino American scientists
Recipients of the Presidential Early Career Award for Scientists and Engineers | Luis von Ahn | [
"Technology"
] | 1,765 | [
"Information systems",
"Human-based computation"
] |
5,649,035 | https://en.wikipedia.org/wiki/Drug%20intolerance | Drug intolerance or drug sensitivity refers to an inability to tolerate the adverse effects of a medication, generally at therapeutic or subtherapeutic doses. Conversely, a patient is said to be "tolerating" a drug when they can tolerate its adverse effects. Some instances of drug intolerance are known to result from genetic variations in drug metabolism.
Pathophysiology
Drugs in systemic circulation have a certain concentration in the blood, which serves as a surrogate marker for how much drug will be delivered throughout the body (how much drug the rest of the body will "see"). There exists a minimum concentration of drug within the blood that will give rise to the intended therapeutic effect (minimum effective concentration, MEC), as well as a minimum concentration of drug that will give rise to an unintended adverse drug event (minimum toxic concentration, MTC). The difference between these two values is generally referred to as the therapeutic window. Different drugs have different therapeutic windows, and different people will have different MECs and MTCs for a given drug. If someone has a very low MTC for a drug, they are likely to experience adverse effects at drug concentrations lower than what it would take to produce the same adverse effects in the general populace; thus, the individual will experience significant toxicity at a dose that is otherwise considered "normal" for the average person. This individual will be considered "intolerant" to that drug.
There are a variety of factors that can affect the MTC, which is often the subject of clinical pharmacokinetics. Variations in MTC can occur at any point in the ADME (absorption, distribution, metabolism, and excretion) process. For example, a patient could possess a genetic defect in a drug metabolizing enzyme in the cytochrome P450 superfamily. While most individuals will possess the effective metabolizing machinery, a person with a defect will have a difficult time trying to clear the drug from their system. Thus, the drug will accumulate within the blood to higher-than-expected concentrations, reaching a MTC at a dose that would otherwise be considered normal for the average person. In other words, in a person that is intolerant to a medication, it is possible for a dose of 10Β mg to "feel" like a dose of 100Β mg, resulting in an overdoseβa "normal" dose can be a "toxic" dose in these individuals, leading to clinically significant effects.
There is also an aspect of drug intolerance that is subjective. Just as different people have different pain tolerances, so too do people have different tolerances for dealing with the adverse effects from their medications. For example, while opioid-induced constipation may be tolerable to some individuals, other people may stop taking an opioid due to the unpleasantness of the constipation even if it brings them significant pain relief.
Examples of drug sensitivity
Tinnitus after a normal dose of aspirin
Aspirin-exacerbated respiratory disease
Liver failure (possibly also kidney failure) after a normal dose of acetaminophen
Muscle pain or weakness due to statin therapy
Analgesic intolerance
Intolerance to analgesics, particularly NSAIDs, is relatively common. It is thought that a variation in the metabolism of arachidonic acid is responsible for the intolerance. Symptoms include chronic rhinosinusitis with nasal polyps, asthma, gastrointestinal ulcers, angioedema, and urticaria.
See also
Adverse drug reaction
Contraindication
DRESS syndrome (drug hypersensitivity syndrome)
Drug tolerance
Food intolerance
References
Pharmacodynamics
Sensitivities
nl:Intolerantie (Geneeskunde) | Drug intolerance | [
"Chemistry"
] | 774 | [
"Pharmacology",
"Pharmacodynamics"
] |
5,649,173 | https://en.wikipedia.org/wiki/Multicopy%20single-stranded%20DNA | Multicopy single-stranded DNA (msDNA) is a type of extrachromosomal satellite DNA that consists of a single-stranded DNA molecule covalently linked via a 2'-5'phosphodiester bond to an internal guanosine of an RNA molecule. The resultant DNA/RNA chimera possesses two stem-loops joined by a branch similar to the branches found in RNA splicing intermediates. The coding region for msDNA, called a "retron", also encodes a type of reverse transcriptase, which is essential for msDNA synthesis.
Discovery
Before the discovery of msDNA in myxobacteria, a group of swarming, soil-dwelling bacteria, it was thought that the enzymes known as reverse transcriptases (RT) existed only in eukaryotes and viruses. The discovery led to an increase in research of the area. As a result, msDNA has been found to be widely distributed among bacteria, including various strains of Escherichia coli and pathogenic bacteria. Further research discovered similarities between HIV-encoded reverse transcriptase and an open reading frame (ORF) found in the msDNA coding region. Tests confirmed the presence of reverse transcriptase activity in crude lysates of retron-containing strains. Although an RNase H domain was tentatively identified in the retron ORF, it was later found that the RNase H activity required for msDNA synthesis is actually supplied by the host.
Retrons
The discovery of msDNA has led to broader questions regarding where reverse transcriptase originated, as genes encoding for reverse transcriptase (not necessarily associated with msDNA) have been found in prokaryotes, eukaryotes, viruses and even archaea. After a DNA fragment coding for the production of msDNA in E. coli was discovered, it was conjectured that bacteriophages might have been responsible for the introduction of the RT gene into E. coli. These discoveries suggest that reverse transcriptase played a role in the evolution of viruses from bacteria, with one hypothesis stating that, with the help of reverse transcriptase, viruses may have arisen as a breakaway msDNA gene that acquired a protein coat. Since nearly all RT genes function in retrovirus replication and/or the movement of transposable elements, it is reasonable to imagine that retrons might be mobile genetic elements, but there has been little supporting evidence for such a hypothesis, save for the observed fact that msDNA is widely yet sporadically dispersed among bacterial species in a manner suggestive of both horizontal and vertical transfer. Since it is not known whether retron sequences per se represent mobile elements, retrons are functionally defined by their ability to produce msDNA while deliberately avoiding speculation about other possible activities.
Function
The function of msDNA remains unknown even though many copies are present within cells. Knockout mutations that do not express msDNA are viable, so the production of msDNA is not essential to life under laboratory conditions. Over-expression of msDNA is mutagenic, apparently as a result of titrating out repair proteins by the mismatched base pairs that are typical of their structure. It has been suggested that msDNA may have some role in pathogenicity or the adaptation to stressful conditions. Sequence comparison of msDNAs from Myxococcus xanthus, Stigmatella aurantiaca, and many other bacteria reveal conserved and hypervariable domains reminiscent of conserved and hypervariable sequences found in allorecognition molecules. The major msDNAs of M. xanthus and S. aurantiaca, for instance, share 94% sequence homology except within a 19 base-pair domain that shares sequence homology of only 42%. The presence of such domains is significant because myxobacteria exhibit complex cooperative social behaviors including swarming and formation of fruiting bodies, while E. coli and other pathogenic bacteria form biofilms that exhibit enhanced antibiotic and detergent resistance. The sustainability of social assemblies that require significant individual investment of energy is generally dependent on the evolution of allorecognition mechanisms that enable groups to distinguish self versus non-self.
Biosynthesis
Biosynthesis of msDNA is purported to follow a unique pathway found nowhere else in DNA/RNA biochemistry. Because of the similarity of the 2'-5' branch junction to the branch junctions found in RNA splicing intermediates, it might at first have been expected that branch formation would be via spliceosome- or ribozyme-mediated ligation. Surprisingly, however, experiments in cell-free systems using purified retron reverse transcriptase indicate that cDNA synthesis is directly primed from the 2'-OH group of the specific internal G residue of the primer RNA. The RT recognizes specific stem-loop structures in the precursor RNA, rendering synthesis of msDNA by the RT highly specific to its own retron. The priming of msDNA synthesis offers a fascinating challenge to our understanding of DNA synthesis. DNA polymerases (which include RT) share highly conserved structural features, which means that their active catalytic sites vary little from species to species, or even between DNA polymerases using DNA as a template, versus DNA polymerases using RNA as a template. The catalytic region of eukaryotic reverse transcriptase comprises three domains termed the "fingers", "palm", and "thumb" which hold the double-stranded primer-template in a right-hand grip with the 3'-OH of the primer buried in the active site of the polymerase, a cluster of highly conserved acidic and polar residues situated on the palm between what would be the index and middle fingers. In eukaryotic RTs, the RNase H domain lies on the wrist below the base of the thumb, but retron RTs lack RNase H activity. The nucleic acid binding cleft, extending from the polymerase active site to the RNase H active site, is about 60 Γ
in length in eukaryotic RTs, corresponding to nearly two helical turns. When eukaryotic RT extends a conventional primer, the growing DNA/RNA double helix spirals along the cleft, and as the double helix passes the RNase H domain, the template RNA is digested to release the nascent strand of cDNA. In the case of msDNA primer extension, however, a long strand of RNA remains attached to the 3'-OH of the priming G. Although it is possible to model an RT-primer template complex which would make the 2'-OH accessible for the priming reaction, further extension of the DNA strand presents a problem: as DNA synthesis progresses, the bulky RNA strand extending from the 3'-OH needs somehow to spiral down the binding cleft without being blocked by steric hindrance. To overcome this issue, the msDNA reverse transcriptase clearly would require special features not shared by other RTs.
References
Further reading
Molecular biology
DNA
RNA | Multicopy single-stranded DNA | [
"Chemistry",
"Biology"
] | 1,427 | [
"Biochemistry",
"Molecular biology"
] |
5,649,176 | https://en.wikipedia.org/wiki/Electron%20emission | In physics, electron emission is the ejection of an electron from the surface of matter, or, in beta decay (Ξ²β decay), where a beta particle (a fast energetic electron or positron) is emitted from an atomic nucleus transforming the original nuclide to an isobar.
Radioactive decay
In Beta decay (Ξ²β decay), radioactive decay results in a beta particle (fast energetic electron or positron in Ξ²+ decay) being emitted from the nucleus
Surface emission
Thermionic emission, the liberation of electrons from an electrode by virtue of its temperature
Schottky emission, due to the:
Schottky effect or field enhanced thermionic emission
Field electron emission, emission of electrons induced by an electrostatic field
Devices
An electron gun or electron emitter, is an electrical component in some vacuum tubes that uses surface emission
Others
Exoelectron emission, a weak electron emission, appearing only from pretreated objects
Photoelectric effect, the emission of electrons when electromagnetic radiation, such as light, hits a material
See also
Positron emission, (of a positron or "antielectron") is one aspect of Ξ²+ decay
Electron excitation, the transfer of an electron to a higher atomic orbital
References
Physical phenomena | Electron emission | [
"Physics"
] | 260 | [
"Physical phenomena"
] |
5,649,660 | https://en.wikipedia.org/wiki/Baekje%20smile | In Korean art history, the Baekje smile is the common smile motif found in Baekje sculpture and bas-relief. Baekje figures express a unique smile that has been described as both enigmatic and subtle. The smile has also been characterized in many different ways from "genuinely glowing" to "thin and mild" to "unfathomable and benevolent".
While Goguryeo sculpture was highly rigid, and Silla sculpture was formalized, Baekje sculpture exhibited distinct characteristics of warmth, softness, and used relaxed poses. Sometimes, the Baekje style has been attributed to influence from the southern Chinese dynasties. The smile gives the Baekje statues a sense of friendliness and an air of pleasantness that is rarely found in other traditions of Buddhist sculpture. The smile is considered to be unique and distinctive.
See also
Archaic smile
Baekje
Korean art
Gilt-bronze Maitreya in Meditation
References
External links
Britannica
Cultural Development of the Three Kingdoms
9th Century Korean Bronze Buddha Shakyamuni
Meditating Bodhisattva β MusΓ©e National Des Arts Asiatiques-Guimet
The Three Kingdoms Period of Korea β ROK embassy to the US
Korean Influence on Japanese Culture
Baekje
Korean art
Visual motifs
Iconography | Baekje smile | [
"Mathematics"
] | 254 | [
"Symbols",
"Visual motifs"
] |
5,649,998 | https://en.wikipedia.org/wiki/Office%20automation | Office automation refers to the varied computer machinery and software used to digitally create, collect, store, manipulate, and relay office information needed for accomplishing basic tasks. Raw data storage, electronic transfer, and the management of electronic business information comprise the basic activities of an office automation system. Office automation helps in optimizing or automating existing office procedures.
The backbone of office automation is a local area network, which allows users to transfer data, mail and voice across the network. All office functions, including dictation, typing, filing, copying, fax, telex, microfilm and records management, telephone and telephone switchboard operations, fall into this category. Office automation was a popular term in the 1970s and 1980s as the desktop computer exploded onto the scene. Advantages of office automation include that it can get many tasks accomplished faster, it eliminates the need for a large staff, less storage is required to store data, and multiple people can update data simultaneously in the event of changes in schedule.
Outline
Businesses can easily purchase and stock their wares with the aid of technology. Many of the manual tasks that used to be done by hand can now be done through hand held devices and UPC and SKU coding. In the retail setting, automation also increases choice. Customers can easily process their payments through automated credit card machines and no longer have to wait in line for an employee to process and manually type in the credit card numbers.
Office payrolls have been automated, which means no one has to manually cut checks, and those checks that are cut can be printed through computer programs. Direct deposit can be automatically set up and this further reduces the manual process, and most employees who participate in direct deposit often find their paychecks come earlier than if they'd have to wait for their checks to be written and then cleared by the bank.
Other ways automation has reduced employee manpower on tasks is automated voice direction. Through the use of prompts, automated phone menus and directed calls, the need for employees to be dedicated to answer the phones has been reduced, and in some cases, eliminated.
See also
Apache OpenOffice
References
Further reading
The Electronic Sweatshop: How Computers Are Transforming the Office of the Future into the Factory of the Past, [by] Barbara Garson. New York: Penguin Books, 1989, cop. 1988. pbk.
Wilkie Office Automation What is OA?, June 2006, Accessed 21 June 2006
Productivity software
Automation software | Office automation | [
"Engineering"
] | 499 | [
"Automation software",
"Automation"
] |
5,650,044 | https://en.wikipedia.org/wiki/Bone%20morphogenetic%20protein%201 | Bone morphogenetic protein 1, also known as BMP1, is a protein which in humans is encoded by the BMP1 gene. There are seven isoforms of the protein created by alternate splicing.
Function
BMP1 belongs to the peptidase M12A family of bone morphogenetic proteins (BMPs). It induces bone and cartilage development. Unlike other BMPs, it does not belong to the TGFΞ² superfamily. It was initially discovered to work like other BMPs by inducing bone and cartilage development. It however, is a metalloprotease that cleaves the C-terminus of procollagen I, II and III. It has an astacin-like protease domain.
It has been shown to cleave laminin 5 and is localized in the basal epithelial layer of bovine skin.
The BMP1 locus encodes a protein that is capable of inducing formation of cartilage in vivo. Although other bone morphogenetic proteins are members of the TGF-beta superfamily, BMP1 encodes a protein that is not closely related to other known growth factors. BMP1 protein and procollagen C proteinase (PCP), a secreted metalloprotease requiring calcium and needed for cartilage and bone formation, are identical. PCP or BMP1 protein cleaves the C-terminal propeptides of procollagen I, II, and III and its activity is increased by the procollagen C-endopeptidase enhancer protein. The BMP1 gene is expressed as alternatively spliced variants that share an N-terminal protease domain but differ in their C-terminal region
Structure
A partial structure of BMP1 was determined through X-Ray diffraction with a resolution of 1.27 Γ
. Crystallization experiments were done by vapor diffusion at a pH of 7.5. This is important because it is close to the pH of the human body, where BMP1 resides in vivo. This BMP1 fragment is 202 residues in length. Its secondary structure is made up of 30% helices, or 10 helices, 61 residues in length, and 15% beta sheets, or 11 strands, 32 residues in length. It contains ligands of an acetyl group and a Zinc ion.
A Ramachandran plot was constructed for BMP1. This plot shows that BMP1 most prefers Phi and Psi angles (Phi, Psi) of around (-60Β°,-45Β°) and (-60Β°, 140Β°). These preferred angles are an estimate of the most clustered data of the Ramachandran plot. The preferred region is much greater in range. 97% of the residues were in preferred regions and 100% of the residues were in the allowed region, with no outliers.
References
Further reading
External links
The MEROPS online database for peptidases and their inhibitors: M12.005
Bone morphogenetic protein
Developmental genes and proteins
ZnMc domain
EGFCA domain
CUB domain | Bone morphogenetic protein 1 | [
"Biology"
] | 644 | [
"Induced stem cells",
"Developmental genes and proteins"
] |
5,650,162 | https://en.wikipedia.org/wiki/Crystal%20Ball%20%28detector%29 | The Crystal Ball was a hermetic particle detector used initially with the SPEAR particle accelerator at the Stanford Linear Accelerator Center beginning in 1979. It was designed to detect neutral particles and was used to discover the Ξ·c meson. Its central section was a spark chamber surrounded by a nearly-complete sphere of scintillating crystals (NaI(Tl)), for which it was named. With the addition of endcaps of similar construction, the detector covered 98% of the solid angle around the interaction point.
After its decommissioning at SLAC, the detector was carried to DESY, where it was used for b-physics experiments.
In 1996, it was moved to the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory, where it was used in a series of pion- and kaon-induced experiments on the proton. Currently it is located at Mainz Microtron facility, where it is being used by the A2 Collaboration for a diverse program of measurements using energy tagged Bremsstrahlung photons.
References
(detector description)
(Ξ·c discovery)
A2 Collaboration website
External links
Crystal Ball experiment record on INSPIRE-HEP
Particle experiments | Crystal Ball (detector) | [
"Physics"
] | 244 | [
"Particle physics stubs",
"Particle physics"
] |
5,650,605 | https://en.wikipedia.org/wiki/N-Acetylgalactosamine | N-Acetylgalactosamine (GalNAc), is an amino sugar derivative of galactose.
Function
In humans it is the terminal carbohydrate forming the antigen of blood group A.
It is typically the first monosaccharide that connects serine or threonine in particular forms of protein O-glycosylation.
N-Acetylgalactosamine is necessary for intercellular communication, and is concentrated in sensory nerve structures of both humans and animals.
GalNAc is also used as a targeting ligand in investigational antisense oligonucleotides and siRNA therapies targeted to the liver, where it binds to the asialoglycoprotein receptors on hepatocytes.
See also
Galactosamine
Globoside
(N-Acetylglucosamine) GlcNAc
References
External links
Acetamides
Hexosamines
Membrane biology | N-Acetylgalactosamine | [
"Chemistry"
] | 194 | [
"Membrane biology",
"Molecular biology"
] |
5,650,682 | https://en.wikipedia.org/wiki/The%20Regenerative%20Medicine%20Institute | The Regenerative Medicine Institute (REMEDI), was established in 2003 as a Centre for Science, Technology & Engineering in collaboration with National University of Ireland, Galway. It obtained an award of β¬14.9 million from Science Foundation Ireland over five years.
It conducts basic research and applied research in regenerative medicine, an emerging field that combines the technologies of gene therapy and adult stem cell therapy. The goal is to use cells and genes to regenerate healthy tissues that can be used to repair or replace other tissues and organs in a minimally invasive approach.
Centres for Science, Engineering & Technology help link scientists and engineers in partnerships across academia and industry to address crucial research questions, foster the development of new and existing Irish-based technology companies, attract industry that could make an important contribution to Ireland and its economy, and expand educational and career opportunities in Ireland in science and engineering. CSETs must exhibit outstanding research quality, intellectual breadth, active collaboration, flexibility in responding to new research opportunities, and integration of research and education in the fields that SFI supports.
References
External links
Regenerative Medicine Institute (REMEDI)
Science Foundation Ireland
National University of Ireland, Galway
Medical research institutes in the Republic of Ireland
Biotechnology organizations
Bioethics research organizations
2003 establishments in Ireland
Scientific organizations established in 2003 | The Regenerative Medicine Institute | [
"Engineering",
"Biology"
] | 263 | [
"Biotechnology organizations"
] |
5,650,792 | https://en.wikipedia.org/wiki/Cockade%20of%20Argentina | The Argentine cockade () is one of the national symbols of Argentina, instituted by decree on February 18, 1812 by the First Triumvirate, who determined that "the national cockade of the United Provinces of the RΓo de la Plata shall be of colours white and light blue [...]".
The National Cockade Day is on May 18, the date on which it is assumed that the cockade was first used by the ladies of Buenos Aires during the events of the 1810 May Revolution.
Origin
The origin of the colours of the cockade and the reasons for their election cannot be accurately established. Among the several versions, one states that the colours white and light blue were first adopted during the British invasions of the RΓo de la Plata in 1806 and 1807 by the Regiment of Patricians, the first urban militia regiment of the RΓo de la Plata. Supposedly, a group of ladies from Buenos Aires first wore the cockade on May 19, 1810, in a visit to then-Colonel Cornelio Saavedra, head of the regiment.
Between May 22 and 25 of the same year, it is known that the , or patriots, identified adherents to the May Revolution by giving them ribbons with those colours. An anonymous manuscript quoted by historian Marfany expresses that on May 21, a Monday, revolutionaries presented themselves as such with white ribbons on their clothes and hats. In Juan Manuel Beruti's memoirs, , it is commented on the use of white ribbons on clothes and cockades with olive branches on hats.
It was also documented by Spanish functionary Faustino Ansay that when news of the revolution arrived to Mendoza, its supporters started to wear white stripes. A report attributed to RamΓ³n Manuel de Pazos says that on May 21, 1810, Domingo French and Antonio Beruti distributed said stripes as a sign of peace and unity between patriots and supporters of the Spanish government, but given the hostility of the latter, on May 25 they began spreading red stripes as a reference to the Jacobins. Both colours were later adopted by the members of the cabildo of Tarija as they joined the revolution.
A version by BartolomΓ© Mitre affirmed that French "entered in one of the shops of the and took several tracks of white and light blue stripes. [He] also placed pickets with orders of letting only patriots in and make them put on the distinctive [stripes]", although his statement might be biased due to the fact that blue was one of the colours of the party he was a member of, and which would be later known as the Unitarian Party. Mitre's words are perhaps what originated the erroneous belief that attributes the creation of the Argentine cockade to French and Beruti. In any case, it is known that in March 1811 the Patriotic Society created by people from Mariano Moreno's circle wore the white and light blue ribbons.
Relation with the Argentine flag
In a note dated February 13, 1812, Manuel Belgrano solicited the triumvirate the use of the white and light blue national cockade, having to omit red since the Spanish troops and the royalists had been using it as a distinctive colour against the revolution. A legend says Belgrano was inspired by the sky and the clouds when choosing such colours, but he took them from the ribbons and cockades that were already being used.
On February 18, 1812, the government decided to create the national cockade of the United Provinces of the RΓo de la Plata with light blue at its outer border and centre, and white between both.
Belgrano then used the same colours to design the national flag, to which his men first took oath on February 27. That day the triumvirate ordered Belgrano to take charge of the Northern Army () and as a result of his immediate departure, he did not become aware that the government had rejected the new flag.
References
National symbols of Argentina
Argentina | Cockade of Argentina | [
"Mathematics"
] | 797 | [
"Cockades",
"Symbols"
] |
5,651,308 | https://en.wikipedia.org/wiki/Time%20to%20first%20fix | Time to first fix (TTFF) is a measure of the time required for a GPS navigation device to acquire satellite signals and navigation data, and calculate a position solution (called a fix).
Scenarios
The TTFF is commonly broken down into three more specific scenarios, as defined in the GPS equipment guide:
Cold factory
The receiver is missing or has inaccurate estimates of its position, velocity, the time, or the visibility of any of the GPS satellites. As such, the receiver must systematically search for all possible satellites. After acquiring a satellite signal, the receiver can begin to obtain approximate information on all the other satellites, called the almanac. This almanac is transmitted repeatedly over 12.5Β minutes. Almanac data can be received from any of the GPS satellites and is considered valid for up to 180Β days.
Warm normal
The receiver has estimates of the current time within 20Β seconds, the current position within 100Β kilometers, its velocity within 25Β m/s, and it has valid almanac data. It must acquire each satellite signal and obtain that satellite's detailed orbital information, called ephemeris data. Each satellite broadcasts its ephemeris data every 30Β seconds with validity of up to 4Β hours.
Hot standby
The receiver has valid time, position, almanac, and ephemeris data, enabling a rapid acquisition of satellite signals. The time required of a receiver in this state to calculate a position fix may also be termed time to subsequent fix (TTSF).
Many receivers can use as many as twelve channels simultaneously, allowing quicker fixes (especially in a cold case for the almanac download). Many cell phones reduce the time to first fix by using assisted GPS (A-GPS): they acquire almanac and ephemeris data over a fast network connection from the cell-phone operator rather than over the slow radio connection from the satellites.
The TTFFs for a cold start is typically between 2 and 4Β minutes, a warm start is 45Β seconds (or shorter), and a hot start is 22Β seconds (or only a few seconds). In older hardware where satellite search is slower, a cold start may take more than the full 12.5Β minutes.
See also
Global Positioning System (GPS)
GPS signals
High-sensitivity GPS
Satellite navigation solution
References
External links
US Coast Guard, Navigation Center's NAVSTAR GPS User Equipment Introduction .
Global Positioning System
Satellite navigation | Time to first fix | [
"Technology",
"Engineering"
] | 484 | [
"Global Positioning System",
"Wireless locating",
"Aircraft instruments",
"Aerospace engineering"
] |
5,651,414 | https://en.wikipedia.org/wiki/Warren%20%28burrow%29 | A warren is a network of interconnected burrows, dug by rabbits. Domestic warrens are artificial, enclosed establishments of animal husbandry dedicated to the raising of rabbits for meat and fur. The term evolved from the medieval Anglo-Norman concept of free warren, which had been, essentially, the equivalent of a hunting license for a given woodland.
Architecture of the domestic warren
The cunicularia of the monasteries may have more closely resembled hutches or pens, than the open enclosures with specialized structures which the domestic warren eventually became. Such an enclosure or close was called a cony-garth, or sometimes conegar, coneygree or "bury" (from "burrow").
Moat and pale
To keep the rabbits from escaping, domestic warrens were usually provided with a fairly substantive moat, or ditch filled with water. Rabbits generally do not swim and avoid water. A pale, or fence, was provided to exclude predators.
Pillow mounds
The most characteristic structure of the "cony-garth" ("rabbit-yard") is the pillow mound. These were "pillow-like", oblong mounds with flat tops, frequently described as being "cigar-shaped", and sometimes arranged like the letter β¨Eβ© or into more extensive, interconnected rows. Often these were provided with pre-built, stone-lined tunnels. The preferred orientation was on a gentle slope, with the arms extending downhill, to facilitate drainage. The soil needed to be soft, to accommodate further burrowing.
This type of architecture and animal husbandry has become obsolete, but numerous pillow mounds are still to be found in Britain, some of them maintained by English Heritage, with the greatest density being found on Dartmoor.
Further evolution of the term
Ultimately, the term "warren" was generalized to include wild burrows. According to the 1911 Encyclopædia Britannica: The word thus became used of a piece of ground preserved for these beasts of warren. It is now applied loosely to any piece of ground, whether preserved or not, where rabbits breed.
The use is further extended to any system of burrows, e.g., "prairie dog warren". By 1649, the term was applied to inferior, crowded human accommodations and meant "cluster of densely populated living spaces" (OED). Contemporarily, the leading use seems to be in the stock phrase "warren of cubicles" in the workplace.
References
Further reading
Livestock
Agricultural buildings
Buildings and structures used to confine animals
Humanβanimal interaction
Shelters built or used by animals
Leporidae | Warren (burrow) | [
"Biology"
] | 520 | [
"Behavior",
"Animals",
"Ethology",
"Shelters built or used by animals",
"Humanβanimal interaction",
"Humans and other species"
] |
5,651,750 | https://en.wikipedia.org/wiki/ABCN | 1,1β²-Azobis(cyclohexanecarbonitrile) or ACHN is a radical initiator. The molecular formula is NCC6H10N=NC6H10CN. It is a white solid that is soluble in aromatic solvents.
ACHN has a 10-hour half-life in toluene at 88Β Β°C.
See also
Azobisisobutylonitrile (AIBN) is another commonly used free radical initiator
References
Azo compounds
Nitriles
Radical initiators | ABCN | [
"Chemistry",
"Materials_science"
] | 116 | [
"Radical initiators",
"Functional groups",
"Organic compounds",
"Polymer chemistry",
"Reagents for organic chemistry",
"Nitriles",
"Organic compound stubs",
"Organic chemistry stubs"
] |
5,652,077 | https://en.wikipedia.org/wiki/Logic%20level | In digital circuits, a logic level is one of a finite number of states that a digital signal can inhabit. Logic levels are usually represented by the voltage difference between the signal and ground, although other standards exist. The range of voltage levels that represent each state depends on the logic family being used.
A logic-level shifter can be used to allow compatibility between different circuits.
2-level logic
In binary logic the two levels are logical high and logical low, which generally correspond to binary numbers 1 and 0 respectively or truth values true and false respectively. Signals with one of these two levels can be used in Boolean algebra for digital circuit design or analysis.
Active state
The use of either the higher or the lower voltage level to represent either logic state is arbitrary. The two options are active high (positive logic) and active low (negative logic). Active-high and active-low states can be mixed at will: for example, a read only memory integrated circuit may have a chip-select signal that is active-low, but the data and address bits are conventionally active-high. Occasionally a logic design is simplified by inverting the choice of active level (see De Morgan's laws).
The name of an active-low signal is historically written with a bar above it to distinguish it from an active-high signal. For example, the name Q, read Q bar or Q not, represents an active-low signal. The conventions commonly used are:
a bar above ()
a leading slash (/Q)
a leading exclamation mark (!Q)
a lower-case n prefix or suffix (nQ, Qn or Q_n)
an upper-case N suffix (Q_N)
a trailing # (Q#), or
an _B or _L suffix (Q_B or Q_L).
Many control signals in electronics are active-low signals (usually reset lines, chip-select lines and so on). Logic families such as TTL can sink more current than they can source, so fanout and noise immunity increase. It also allows for wired-OR logic if the logic gates are open-collector/open-drain with a pull-up resistor. Examples of this are the IΒ²C bus, CAN bus, and PCI bus.
Some signals have a meaning in both states and notation may indicate such. For example, it is common to have a read/write line designated R/W, indicating that the signal is high in case of a read and low in case of a write.
Logic voltage levels
The two logical states are usually represented by two different voltages, but two different currents are used in some logic signaling, like digital current loop interface and current-mode logic. High and low thresholds are specified for each logic family. When below the low threshold, the signal is low. When above the high threshold, the signal is high. Intermediate levels are undefined, resulting in highly implementation-specific circuit behavior.
It is usual to allow some tolerance in the voltage levels used; for example, 0 to 2 volts might represent logic 0, and 3 to 5 volts logic 1. A voltage of 2 to 3 volts would be invalid and occur only in a fault condition or during a logic-level transition. However, few logic circuits can detect such a condition, and most devices will interpret the signal simply as high or low in an undefined or device-specific manner. Some logic devices incorporate Schmitt trigger inputs, whose behavior is much better defined in the threshold region and have increased resilience to small variations in the input voltage. The problem of the circuit designer is to avoid circumstances that produce intermediate levels, so that the circuit behaves predictably.
Nearly all digital circuits use a consistent logic level for all internal signals. That level, however, varies from one system to another. Interconnecting any two logic families often required special techniques such as additional pull-up resistors or purpose-built interface circuits known as level shifters. A level shifter connects one digital circuit that uses one logic level to another digital circuit that uses another logic level. Often two level shifters are used, one at each system: A line driver converts from internal logic levels to standard interface line levels; a line receiver converts from interface levels to internal voltage levels.
For example, TTL levels are different from those of CMOS. Generally, a TTL output does not rise high enough to be reliably recognized as a logic 1 by a CMOS input, especially if it is only connected to a high-input-impedance CMOS input that does not source significant current. This problem was solved by the invention of the 74HCT family of devices that uses CMOS technology but TTL input logic levels. These devices only work with a 5Β V power supply.
More than two levels
3-value logic
Though rare, ternary computers evaluate base 3 three-valued or ternary logic using 3 voltage levels.
3-state logic
In three-state logic, an output device can be in one of three possible states: 0, 1, or Z, with the last meaning high impedance. This is not a voltage or logic level, but means that the output is not controlling the state of the connected circuit.
4-value logic
Four valued logic adds a fourth state, X (don't care), meaning the value of the signal is unimportant and undefined. It means that an input is undefined, or an output signal may be chosen for implementation convenience (see ).
9-level logic
IEEE 1164 defines 9 logic states for use in electronic design automation. The standard includes strong and weakly driven signals, high impedance and unknown and uninitialized states.
Multi-level cells
In solid-state storage devices, a multi-level cell stores data using multiple voltages. Storing n bits in one cell requires the device to reliably distinguish 2n distinct voltage levels.
Line coding
Digital line codes may use more than two states to encode and transmit data more efficiently. Examples include alternate mark inversion and 4B3T from telecommunications, and pulse-amplitude modulation variants used by Ethernet over twisted pair. For instance, 100BASE-TX uses MLT-3 encoding with three differential voltage levels (β1V, 0V, +1V) while 1000BASE-T encodes data using five differential voltage levels (β1V, β0.5V, 0V, +0.5V, +1V). Once received, the line coding is converted back to binary.
See also
Logic family
Digital current loop interface
References
External links
Positive Logic (active-high) and Negative logic (active-low )
Simple MOSFET-based logic level conversion or level-shift based on work done by Herman Schutte at Philips Semiconductors Systems Laboratory in Eindhoven
Digital electronics | Logic level | [
"Engineering"
] | 1,395 | [
"Electronic engineering",
"Digital electronics"
] |
5,652,374 | https://en.wikipedia.org/wiki/Immobiliser | An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key (transponder or smart key) is present. This prevents the vehicle from being "hot wired" after entry has been achieved and thus reduces motor vehicle theft. Research shows that the uniform application of immobilisers reduced the rate of car theft by 40%.
Description
The electric immobiliser/alarm system was invented by St. George Evans and Edward Birkenbuel and patented in 1919. They developed a 3x3 grid of double-contact switches on a panel mounted inside the car so when the ignition switch was activated, current from the battery (or magneto) went to the spark plugs allowing the engine to start, or immobilizing the vehicle and sounding the horn. The system settings could be changed each time the car was driven. Modern immobiliser systems are automatic, meaning the owner does not have to remember to activate it.
Early models used a static code in the ignition key (or key fob) which was recognised by an RFID loop ( transponder ) around the lock barrel and checked against the vehicle's engine control unit (ECU) for a match. If the code is unrecognised, the ECU will not allow fuel to flow and ignition to take place.
Later models use rolling codes or advanced cryptography to defeat copying of the code from the key or ECU (smart key).
The microcircuit inside the key is activated by a small electromagnetic field which induces current to flow inside the key body, which in turn broadcasts a unique binary code, which is read by the automobile's ECU. When the ECU determines that the coded key is both current and valid, the ECU activates the fuel-injection sequence.
In some vehicles, attempts to use an unauthorised or "non-sequenced" key cause the vehicle to activate a timed "no-start condition" and in some highly advanced systems, even use satellite or mobile phone communication to alert a security firm that an unauthorised attempt was made to code a key.
Coincidentally, this information is often recorded in modern automobile ECUs as part of their on-board diagnostics which may record many other variables including speed, temperature, driver weight, geographic location, throttle position and yaw angle. This information can be used during insurance investigations, warranty claims or technical troubleshooting.
Regulation
Immobilisers have been mandatory in all new cars sold in Germany since 1 January 1998, in the United Kingdom since 1 October 1998, in Finland since 1998, in Australia since 2001.
In September 2007, a Transport Canada regulation mandated the installation of engine immobilisers in all new lightweight vehicles and trucks manufactured in Canada.
Availability by car brand
Honda was the first motorcycle manufacturer to include immobilisers on its products in the 1990s.
Add-on immobilisers are available for older cars or vehicles that do not come equipped with factory immobilisers. The insurance approval for a self-arming immobiliser is known as "Thatcham 2" after the Motor Insurance Repair Research Centre in Thatcham, England. Approved immobilisers must intercept at least two circuits; typically the low-voltage ignition circuit and the fuel pump circuit. Some may also intercept the low-current starter motor circuit from the key switch to the relay.
Lack of immobilizers in many Kia and Hyundai U.S. models after 2010 and before mid-2021 made these cars targets for theft in the early 2020s, especially in Milwaukee County, Wisconsin and Columbus, Ohio. The Kia Challenge TikTok trend was linked to series of Hyundai/Kia vehicle thefts in 2022.
Cracking
Numerous vulnerabilities have been found in the immobilisers designed to protect modern cars from theft. Many vehicle immobilisers use the Megamos chip, which has been proven to be crackable. The Megamos transponder is one of many different transponders found in today's immobiliser systems and also comes in many different versions. Hacking of an immobiliser in the real world would be performed on the vehicle, not on the key. It would be faster to program a new key to the vehicle than to try to clone the existing key, especially on modern vehicles.
Some immobiliser systems tend to remember the last key code for so long that they may even accept a non-transponder key even after the original key has been removed from the ignition for a few minutes.
Effectiveness
A 2016 study in the Economic Journal found that the immobiliser lowered the overall rate of car theft by about 40% between 1995 and 2008. The benefits in terms of prevented thefts were at least three times higher than the costs of installing the device.
See also
Anti-theft system
Anti-hijack system
Ignition interlock device
Vehicle Theft Protection Program
Remote keyless system
Key (lock)
References
External links
Motor Insurance Repair Research Centre in Thatcham
Theft Deterrent Program at the Insurance Bureau of Canada
Instructions on how to replace a car key
Auto parts
Automotive accessories
Radio-frequency identification
Vehicle security systems
20th-century inventions | Immobiliser | [
"Engineering"
] | 1,071 | [
"Radio-frequency identification",
"Radio electronics"
] |
5,652,450 | https://en.wikipedia.org/wiki/Biological%20process | Biological processes are those processes that are necessary for an organism to live and that shape its capacities for interacting with its environment. Biological processes are made of many chemical reactions or other events that are involved in the persistence and transformation of life forms.
Regulation of biological processes occurs when any process is modulated in its frequency, rate or extent. Biological processes are regulated by many means; examples include the control of gene expression, protein modification or interaction with a protein or substrate molecule.
Homeostasis: regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature
Organization: being structurally composed of one or more cellsΒ β the basic units of life
Metabolism: transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
Growth: maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
Response to stimuli: a response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis.
Interaction between organisms. the processes by which an organism has an observable effect on another organism of the same or different species.
Also: cellular differentiation, fermentation, fertilisation, germination, tropism, hybridisation, metamorphosis, morphogenesis, photosynthesis, transpiration.
See also
Chemical process
Life
Organic reaction
References
Biological concepts | Biological process | [
"Biology"
] | 372 | [
"nan"
] |
5,652,483 | https://en.wikipedia.org/wiki/COWI%20A/S | COWI A/S is an international consulting group, specializing in engineering, environmental science and economics, with headquarters located in Lyngby, Denmark.
It has been involved in more than 50,000 projects in 175 countries and has approximately 7,300 employees, including engineers, biologists, geologists, economists, surveyors, anthropologists, sociologists and architects.
History
COWI was founded in 1930 by civil engineer Christen Ostenfeld in Copenhagen. Prior to establishing the business, Ostenfeld had spent several years in both France and Switzerland, during which time he developed an international outlook, independence and close cooperation with the research community that helped shape the future business. During 1931, Ostenfeld was hired to reconstruct Copenhagen's run-down Scala Theatre; having only a short timeframe to conduct the work, he opted to use prefabricated steel elements that did not need any scaffolding to speed up construction. The company's first international project was undertaken in 1935 with the design of the Danish pavilion for the Brussels International Exposition of 1935, which was made extensive use of prefabricated locally-harvested pinewood.
Throughout the 1930s, the firm specialised in construction projects with prefabricated elements and long-span roofs. It was also involved in the design of various bridges; the company's first major undertaking in this sector was the Aggersund bridge. Built for the Danish state under a private tender and opened in 1942, the bridge's design was influenced by modern techniques acquired in Czechoslovakia. Other innovative techniques and technologies were acquired throughout the 1940s, one such innovation being prestressed concrete; the original techniques, acquired from France, were further improved by the company and adapted to suit the colder Danish climate. Countless future undertakings by the firm made use of prestressed concrete construction, such as the world's first prestressed concrete silo (1956). Another innovation, created by Ostenfeld and Lauritz Bjerrum, was a telescopic drill that measured ground pressure to work out the bearing capacity of deep soil layers.
The business was heavily impacted by the Invasion of Denmark by Nazi Germany. The company's resources were rationed as the Danish government placed all design work on hold, placing the company's future at jeopardy. Ostenfeld personally travelled across the nation, lobbying for the most important projects to be kept going. Government subsidies were granted for the design of various civil engineering projects in preparation for the postwar years, which permitted the business to continue its engineering activities as well to get a valuable lead on planning work. As soon as the conflict ended, various construction projects were quickly launched and contact was re-established with the company's international colleagues as it became safe to freely communicate and travel once again.
During 1946, Wriborg W. JΓΈnson became an equal partner in the business. The initials of the two senior partners lent the company its name; between 1946 and 1973, the company operated as a partnership under the name of Chr. Ostenfeld & W. JΓΈnson (often shortened to O&J. During the 1950s, the company began to expand internationally; by 1953, a quarter of all turnover was being generated outside Denmark. Its first international office was established in Paris in response to the large and lucrative market opportunities for silos in France. During 1957, O&J designed the Fredrikstad Bridge in Norway, which was the company's first large bridge outside Denmark.
An increasing variety of projects were undertaken by the company throughout the 1960s following a considerable uptick in orders. In addition to regular silo work, it was involved in the building of Tamale Airport in Ghana, the Danish Embassy in Paris, a nuclear research facility in Geneva, the Little Belt Bridge in Denmark, renovated government facilities in Bahrain, numerous dams and bridges across the Middle East, and residential housing on permafrost in Greenland. One scheme, a motorway project between Baghdad and the Turkish border, had to be abandoned following the outbreak of the Iran-Iraq War. By the end of the decade, the firm had no less than 400 employees, a quarter of which were based outside Denmark.
During 1972, Ostenfeld retired from the firm; in the following year, the company's ownership was transferred to a foundation chaired by Wriborg JΓΈnson and a new name was adopted "COWIconsult, RΓ₯dgivende IngeniΓΈrer A/S", ("COWIconsult, Consulting Engineers and Planners A/S") that was based on the two senior partnersβ initials. Across the 1970s, in response to the energy crises of this decade, the company broadened its horizon from specialising primarily in bridges and structural engineering to building in the fields of energy and environment, such as combined heat and power. Among other environmental issues, it moved into with water treatment, waste management and air pollution, gradually becoming an established environmental consultant, working with local authorities, utility companies, and businesses alike in this capacity. In collaboration with the World Bank and the United Nations Development Programme, it has worked on numerous projects in developing countries such as Nigeria, Kenya and Swaziland. By 1979, COWIconsult has more than 800 staff, and a third of its turnover is generated outside of Denmark.
In 1995, the company was renamed once again to the current COWI A/S. By this point, it had developed into a full-service consultant in social analysis, urban development, transport and welfare.
During the new millennium, a number of strategic acquisitions were made in Scandinavia and the UK, significantly increasing the number of employees and undertakings of the business. In 2008, the firm bought Flint & Neill, a UK civil and structural engineering consultancy specialising in bridges. In November 2014, the firm acquired Donaldson Associates Ltd, a UK base tunneling specialist company; at the time of acquisition, Donaldson Associates Ltd had 150 staff, operating from five UK offices and one international office in Hong Kong. In November 2018, the firm acquired the Danish architecture firm Arkitema Architects; it was the largest acquisition by COWI at that time.
In early 2022, COWI acquired US-based Finley Engineering Group. That same year, COWI announced that the company will no longer participate in tenders for new fossil energy projects.
Ownership
COWI Holding A/S is an unlisted Danish public limited liability company jointly owned by the COWIfonden (the COWIfoundation) holding 85% of shares with the remaining 15% of company shares held by current and former employees from eight countries where COWI operates. The company regards employee shareholders as co-owners. The current company structure was adapted in 2010.
Sustainability
With the rise of awareness about the climate crisis, COWI prioritised the need for action through overall organisational change. In 2022, COWI developed and adopted a new vision and strategy called FUTURE-NOW that puts sustainability at the centre of the company. The strategy works to accelerate the green transition and means that COWI became the first among engineering consultancies to stop taking on fossil fuel projects. Instead, COWI now allocates all resources to projects that move its customers towards sustainability. The goal is that 100 per cent of COWI's revenue must come from projects driving sustainability. COWI has established sustainability targets.
See also
Γresund Bridge
Copenhagen Metro
Great Belt Fixed Link
Strait of Messina Bridge
Γanakkale 1915 Bridge
References
External links
In-depth company history (English)
International engineering consulting firms
Construction and civil engineering companies of Denmark
Service companies based in Copenhagen
Companies based in Lyngby-Taarbæk Municipality
Danish companies established in 1930
Construction and civil engineering companies established in 1930
Design companies established in 1930
Strait of Messina Bridge | COWI A/S | [
"Engineering"
] | 1,572 | [
"Engineering consulting firms",
"International engineering consulting firms"
] |
5,652,499 | https://en.wikipedia.org/wiki/Mother%20Camels | The protecting Mother Camels (Arabic Ψ§ΩΨΉΩΨ§Ψ¦Ψ° alΚ½awaΚΌid) is an asterism in the constellation of Draco described by ancient Arabic nomadic tribes. The asterism was interpreted as a ring of mother camels β Beta Draconis (Rastaban), Gamma Draconis (Eltanin), Nu Draconis (Kuma) and Xi Draconis (Grumium) β surrounding a foal (the faint star Alruba), with another mother camel, Mu Draconis (Alrakis) running to join them.
The Arabs did not see the constellation Draco as it is now. The Mother Camels were protecting the foal from the attack of two wolves or jackals β Zeta Draconis (Aldhibah) and Eta Draconis (Athebyne). The faint pair Omega Draconis and 27 Draconis was known as the "wolf's claws" (Ψ§ΩΨ£ΨΈΩΨ§Ψ± Ψ§ΩΨ°Ψ¦Ψ¨ al-ΚΌaαΊfΔr al-dhiΚΌb).
References
Draco (constellation) | Mother Camels | [
"Astronomy"
] | 231 | [
"Constellations",
"Draco (constellation)"
] |
5,652,832 | https://en.wikipedia.org/wiki/Stewart%E2%80%93Walker%20lemma | The StewartβWalker lemma provides necessary and sufficient conditions for the linear perturbation of a tensor field to be gauge-invariant. if and only if one of the following holds
1.
2. is a constant scalar field
3. is a linear combination of products of delta functions
Derivation
A 1-parameter family of manifolds denoted by with has metric . These manifolds can be put together to form a 5-manifold . A smooth curve can be constructed through with tangent 5-vector , transverse to . If is defined so that if is the family of 1-parameter maps which map and then a point can be written as . This also defines a pull back that maps a tensor field back onto . Given sufficient smoothness a Taylor expansion can be defined
is the linear perturbation of . However, since the choice of is dependent on the choice of gauge another gauge can be taken. Therefore the differences in gauge become . Picking a chart where and then which is a well defined vector in any and gives the result
The only three possible ways this can be satisfied are those of the lemma.
Sources
Describes derivation of result in section on Lie derivatives
Tensors
Lemmas in analysis | StewartβWalker lemma | [
"Mathematics",
"Engineering"
] | 238 | [
"Theorems in mathematical analysis",
"Tensors",
"Lemmas",
"Lemmas in mathematical analysis"
] |
5,652,850 | https://en.wikipedia.org/wiki/Biodegradable%20polythene%20film | Polyethylene or polythene film biodegrades naturally, albeit over a long period of time. Methods are available to make it more degradable under certain conditions of sunlight, moisture, oxygen, and composting and enhancement of biodegradation by reducing the hydrophobic polymer and increasing hydrophilic properties.
If traditional polyethylene film is littered it can be unsightly, and a hazard to wildlife. Some people believe that making plastic shopping bags biodegradable is one way to try to allow the open litter to degrade.
Plastic recycling improves usage of resources. Biodegradable films need to be kept away from the usual recycling stream to prevent contaminating the polymers to be recycled.
If disposed of in a sanitary landfill, most traditional plastics do not readily decompose. The conditions of a sealed landfill additionally deter degradation of biodegradable polymers.
Polyethylene is a polymer consisting of long chains of the monomer ethylene (IUPAC name ethene). The recommended scientific name polyethene is systematically derived from the scientific name of the monomer.[1] [2] In certain circumstances it is useful to use a structureβbased nomenclature. In such cases IUPAC recommends poly(methylene).[2] The difference is due to the opening up of the monomer's double bond upon polymerisation.
In the polymer industry the name is sometimes shortened to PE in a manner similar to that by which other polymers like polypropylene and polystyrene are shortened to PP and PS respectively. In the United Kingdom the polymer is commonly called polythene, although this is not recognised scientifically.
The ethene molecule (known almost universally by its common name ethylene) C2H4 is CH2=CH2, Two CH2 groups connected by a double bond, thus:
Polyethylene is created through polymerization of ethene. It can be produced through radical polymerization, anionic addition polymerization, ion coordination polymerization or cationic addition polymerization. This is because ethene does not have any substituent groups that influence the stability of the propagation head of the polymer. Each of these methods results in a different type of polyethylene.
Alternatives to biodegradable polythene film
Polythene or polyethylene film will naturally fragment and biodegrade, but it can take many decades to do this. There are two methods to resolve this problem. One is to modify the carbon chain of polyethylene with an additive to improve its degradability and then its biodegradability; the other is to make a film with similar properties to polyethylene from a biodegradable substance such as starch. The latter are however much more expensive.
Starch based or biobased (hydrodegradable) film
This type is made from corn (maize), potatoes or wheat. This form of biodegradable film meets the ASTM standard (American Standard for Testing Materials) and European Norm EN13432 for compostability as it degrades at least 90% within 90 days or less at 140 degrees F. However, actual products made with this type of film may not meet those standards.
Examples of polymers made from starch
Polycaprolactone (PCL)
Polyvinyl alcohol (PVA)
Polylactic acid (PLA)
The heat, moisture and aeration in an industrial composting plant are required for this type of film to biodegrade, so it will not therefore readily degrade if littered in the environment.
Pros & cons of starch based film/bag
Pros
It is "compostable" under industrial conditions.
Reduced fossil fuel content (depending on loading of filler.)
Cons
Is more expensive than its non-biodegradable counterpart
Source of starch can be problematic (competition against food use, rainforests being cleared to grow crops for bioplastics)
Fossil fuels are burned and CO2 produced in the agricultural production process.
Poorer mechanical strength than additive based example β filling a starch bag with wet leaves and placing it curbside can result in the bottom falling out when a haulier picks it up.
Often not strong enough for use in high-speed machines
Degradation in a sealed landfill takes at least 6 months.
Emits CO2 in aerobic conditions and methane under anaerobic conditions
Limited Shelf life. Conditions must be respected for stockage.
If mixed with other plastics for recycling, the recycling process is compromised.
Typical applications
Carrier bag, refusal sacks, vegetable bags, food films, agricultural films, mailing films. However, these applications are still very limited compared to those of petroleum based plastic films.
Additive based
Additives can be added to conventional polymers to make them either oxodegradable or more hydrophilic to facilitate microbial attack.
Oxodegradable
These films are made by incorporating an additive within normal polymers to provide an oxidative and then a biological mechanism to degrade them. This typically takes 6 months to 1 year in the environment with adequate exposure to oxygen Degradation is a two-stage process; first the plastic is converted by reaction with oxygen (light, heat and/or stress accelerates the process but is not essential) to hydrophilic low molecular-weight materials and then these smaller oxidized molecules are biodegraded, i.e. converted into carbon dioxide, water and biomass by naturally occurring microorganisms. Commercial competitors and their trade associations allege that the process of biodegradation stops at a certain point, leaving fragments, but they have never established why or at what point. In fact Oxo-biodegradation of polymer material has been studied in depth at the Technical Research Institute of Sweden and the Swedish University of Agricultural Sciences. A peer-reviewed report of the work was published in Vol 96 of the journal of Polymer Degradation & Stability (2011) at page 919β928. It shows 91% biodegradation in a soil environment within 24 months, when tested in accordance with ISO 17556.
This is similar to the breakdown of woody plant material where lignin is broken down and forms a humus component improving the soil quality.
There is however a lot of controversy about these types of bags. The complete biodegradation is disputed and claimed not to take place. Many countries are now also thinking to ban this type of bags altogether
Enhancing hydrophilicity of the polymer
These films are inherently biodegradable over a long period of time. Enhancement of the polymer by adding in additives to change the hydrophobic nature of the resin to slightly hydrophilic allows microorganisms to consume the macromolecules of the product, these products often are confused with oxobiodegradable products, but work in a different way. Enhancing of the hydrophilicity of the polymer allows fungus and bacteria to consume the polymer at a faster rate utilizing the carbon inside the polymer chain for energy. These additives attract certain microorganisms found in nature and many tests have been completed on the mixing of synthetic and biobased materials which are inherently biodegradable for enhancing the biodegradability of synthetic polymers that are not as fast to biodegrade.
Pros and cons of additive based film/bag
Pros
Much cheaper than starch-based plastics
Can be made with normal machinery, and can be used in high speed machines, so no need to change suppliers and no loss of jobs
Materials are well known
Does not compete against food production
These films look, act and perform just like their non-degradable counterparts, during their programmed service-life but then break down if discarded.
They can be recycled with normal plastics.
They are certified non-toxic, and safe for food-contact
Some bags degrade at about the same rate as a leaf. In fact, when used as bin liners, bags can start degrading after three or four days of being in the bin.
Cons
Degradation depends on access to air
Not designed to degrade in landfill, but can be safely landfilled. Will degrade if oxygen is present, but will NOT emit methane in landfill
European or American (EN13432 D6400)Standards on compostable products are not appropriate, as not designed for composting. They should be tested according to ASTM D6954 or (as from 1 Jan 1010) UAE norm 5009:2009
They are not suitable for PET or PVC
Precise rate of degradation/biodegradation cannot be predicted, but will be faster than nature's wastes such as straw or twigs, and much faster than normal plastic
Like normal plastics they are made from a by-product of oil or natural gas
If mixed with other plastics for recycling, the recycling process is compromised.
Typical applications
Trash Bags, Garbage Bags, Compost Bags, Carrier bag, Agricultural Film, Mulch Film, produce bags, - in fact all forms of short-life plastic film packaging
See also
Biodegradable plastic
Bioplastic
Plastic bag
Plastic recycling
Packaging
Photodegradation
References
BBC News: "All Tesco bags 'to be degradable" 10 May 2006 http://news.bbc.co.uk/1/hi/uk/4758419.stm
BBC News: "Degradable carrier bags launched" 2 September 2002 http://news.bbc.co.uk/1/hi/uk/2229698.stm
Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009,
Biodegradable materials | Biodegradable polythene film | [
"Physics",
"Chemistry"
] | 1,979 | [
"Biodegradation",
"Biodegradable materials",
"Materials",
"Matter"
] |
5,652,959 | https://en.wikipedia.org/wiki/Kidney%20dish | A kidney dish (British English) or emesis basin (American English) is a shallow basin with a kidney-shaped base and sloping walls used in medical and surgical wards to receive soiled dressings and other medical waste. Generally, the volume of a pulp kidney dish (or "vomit dish") is 700 mL. Its length is 25Β cm-26Β cm, its width 11Β cm. The shape of the dish allows it to be held against the patient's body to catch any falling fluids or debris. Various sizes of emesis basins are common in healthcare settings, including facilities such as nursing homes that may have bedridden patients.
Reusable kidney dishes are usually made of stainless steel. During the first half of the 20th century, kidney dishes were commonly made of enamelled iron.
Bessie Blount invented a disposable kidney dish. It was a kidney-shaped disposable cardboard dish made out of flour, water, and newspaper that was baked until the material was hard.
Disposable molded pulp kidney dishes have been replacing reusable kidney dishes because single-use products can decrease cross-communication of pathogens. Each year, more than 100 million pulp kidney dishes are used in hospital or family care.
Uses
Contrary to its name, emesis basins are not usually used for vomiting, as the depth, size, and sloping walls all contribute to spilling or splashing the vomit rather than catching it. For this purpose, a plastic bag or wash basin is often preferred, especially by ambulance crews who may need to receive the vomit while driving rapidly, and then hand it over for analysis.
Emesis basins are suited for more controlled situations. When washing out a small wound, for example, sometimes the wash water is applied from above with an emesis basin held underneath to catch the runoff. The concave inner rim helps to conform to the curve of the body.
References
Medical equipment
Waste containers | Kidney dish | [
"Biology"
] | 389 | [
"Medical equipment",
"Medical technology"
] |
5,652,979 | https://en.wikipedia.org/wiki/Flash%20flood%20warning | A flash flood warning (SAME code: FFW) is a severe weather warning product of the National Weather Service that is issued by national weather forecasting agencies throughout the world to alert the public that a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain, or occasionally after a dam break. Rainfall intensity and duration, topography, soil conditions, and ground cover contribute to flash flooding.
Most flash floods occur when there is a heavy amount of precipitation falling in an area and that water is then channeled through streams or narrow gullies. Flash floods may take minutes or hours to develop. It is possible to experience a flash flood without witnessing any rain.
Flash flood alerts
There are two types of alerts for flash floods which are issued by the National Weather Service. One is a flash flood watch, which means that conditions are favorable for flash flooding, and the other is a flash flood warning, meaning that a flash flood is occurring or one will occur imminently and is usually issued when there are strong weather radar echoes for an area that is prone to flash flooding.
Flash floods can also occur because of a dam or levee failure, or because of a sudden release of water held by an ice jam.
Residents are usually urged to do the following when flash flooding is imminent:
Be aware of any signs of heavy rain
Move to higher ground if rapidly rising water is seen or heard
Not attempt to cross the flowing water
In addition, some NWS Weather Forecast Offices have instituted an enhanced flash flood warning, referred to as a flash flood emergency (or as termed by the Albany, New York office as a flash flood warning emergency), which indicates a severe flooding situation in densely populated areas, similar to the procedure for declaring a tornado emergency.
On August 27, 2017, as Hurricane Harvey brought torrential rain to southeast Texas, the NWS issued a "Flash Flood Emergency for Catastrophic Life Threatening Flooding."
On September 10, 2017, the NWS issued a Flash Flood Emergency for life-threatening storm surge because of Hurricane Irma in southwestern Florida at the eye landfall.
On February 6, 2020, the NWS issued a Flash Flood Emergency for Tazewell County, Virginia due to a major storm moving through the area which caused the Clinch River to rise to its highest crest in 40 years.
On May 20, 2020, the NWS issued a Flash Flood Emergency for the Tittabawassee River in Midland County, Michigan due to multiple dam failures causing the river to overflow and reach its highest crest since 1986.
On July 6, 2020, the NWS issued a Flash Flood Emergency for Tacony Creek and Frankford Creek, the former situated along Montgomery County and North Philadelphia, Pennsylvania, and the latter along Philadelphia's Frankford neighborhood.
On September 2, 2021, the NWS issued a first ever Flash Flood Emergency for New York City, Philadelphia, Fairfield and New Haven Counties in Connecticut, and most of Central New Jersey a region that stretches over 200 miles, as the remnants of Hurricane Ida transitioned and intensified into a post tropical cyclone causing torrential rains. Some areas reported up to 10 inches of rain in less than an hour. Although the region was forecasted to experience heavy rains, this event is considered unprecedented as such a warning has never been issued to the area. The region had already experienced above average precipitation for most of the Summer due to previous storm systems and tropical storms affecting the area.
On July 28, 2022, the NWS issued several Flash Flood Emergencies in eastern Kentucky for catastrophic and deadly flooding.
On March 27, 2023, the NWS issued a Flash Flood Emergency for a dam break on the Head's Creek Reservoir in Spaulding County, Georgia. A statement was later posted on Twitter.
On September 27, 2024, a Flash Flood Emergency was issued for Metro Atlanta as Hurricane Helene brought catastrophic flooding to the area.
On October 9, 2024, a Flash Flood Emergency was issued for several counties in the Tampa Bay and Big Bend areas of Florida as Hurricane Milton posed life-threatening flooding to a large portion of the West Coast.
Example of a flash flood warning and emergency
Warning
This warning was issued following a dam failure along the Minnesota-Wisconsin border.
Flash Flood Warning
MNC115-WIC013-031-192330-
/O.NEW.KDLH.FF.W.0012.180618T2329Z-180619T2330Z/
/00000.U.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Duluth MN
1203 PM CDT SUN JUN 18 2018
The National Weather Service in Eastern Duluth MN has issued a
* Flash Flood Warning for...
A Dam Failure in...
East central Pine County in east central Minnesota...
Northwestern Douglas County in northwestern Wisconsin...
North central Burnett County in northwestern Wisconsin...
* Until 543 PM CDT
* At 1201 PM CDT, local law enforcement reported the Radigan Flowage
Dam west of Dairyland has failed, causing flash flooding
downstream on the Tamarack River south of the Dam as it flows
towards the Saint Croix River.
* Locations impacted include...
Town Rd T west of Dairyland.
Swedish Highway at the Tamarack River.
Highway T west of Cozy Corner.
Markville Road east of Markville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don`t drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Move to higher ground now. Act quickly to protect your life.
Please report flooding to your local law enforcement agency when you
can do so safely.
&&
LAT...LON 4623 9218 4616 9226 4611 9228 4607 9229
4605 9234 4612 9234 4617 9230 4622 9225
$$
LEThis warning was issued for heavy rainfall.PAC051-102345-
/O.NEW.KPBZ.FF.W.0017.200710T2142Z-200710T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pittsburgh PA
542 PM EDT Fri Jul 10 2020
The National Weather Service in Northern Pittsburgh has issued a
* Flash Flood Warning for...
Central Fayette County in southwestern Pennsylvania...
* Until 745 PM EDT.
* At 542 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2.5 inches of
rain have fallen. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Doppler radar.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other
drainage and low lying areas.
* Some locations that will experience flash flooding include...
Uniontown, South Connellsville, Dunbar, Vanderbilt and Dawson.
Additional rainfall amounts up to 1 inch are possible in the warned
area.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4006 7967 3997 7982 3986 7972 3995 7955
FLASH FLOOD...RADAR INDICATED
$$
Emergency
Flash flood emergency in initial bulletin
This warning, containing both the "Flash Flood Emergency" wording and the Particularly Dangerous Situation wording, was issued in the wake of the devastating flooding that took place in western North Carolina due to the effects of Hurricane Helene.
Flash Flood Warning
NCC023-027-111-291800-
/O.NEW.KGSP.FF.W.0113.240927T2323Z-240929T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
723 PM EDT Fri Sep 27 2024
...FLASH FLOOD EMERGENCY FOR CATAWBA RIVER FROM LAKE JAMES TO LAKE
RHODHISS...
The National Weather Service in Greenville-Spartanburg has issued a
* Flash Flood Warning for...
Central Burke County in western North Carolina...
Southeastern Caldwell County in western North Carolina...
East Central McDowell County in western North Carolina...
* Until 200 PM EDT Sunday.
* At 723 PM EDT, Devastating rainfall of 6-25 (twenty-five) inches
occurred from Wednesday evening through Friday morning from Lake
Hickory to the Catawba River headwaters, with the highest totals
exceeding 2 feet along the Blue Ridge Escarpment across the upper
Catawba River watershed. This is resulting in catastrophic and
historic inflows into Lake James, and releases from Lake James are
causing catastrophic flooding along the Catawba River into Lake
Rhodhiss.
* The latest pool elevations for the upper Catawba River lakes are
as follows (Full Pool is 100.0 feet):
Lake James: 110.3 feet and rising steadily. RECORD BROKEN.
Lake Rhodhiss: 108.1 feet and rising steadily.
* The former record pool elevation at Lake James is 107.36 feet
which occurred in September 8, 2004 during Hurricane Frances.
Major Flood Stage is 110.0 feet.
* The current record pool elevation at Lake Rhodhiss is 110.10 feet
which occurred in August 1940. Major Flood Stage is 110.0 feet.
* This is an unprecedented and extremely dangerous event. Residents
are urged to heed guidance from emergency management and law
enforcement on any potential impacts to property. We are pleading
with drivers to heed any barricades and avoid all flooded areas.
There have been numerous swift water rescues because people are
choosing to risk their lives and the lives of others by failing to
Turn Around Don`t Drown. Please do the right thing and protect
your life, the life of your family, and the lives of those who
risk theirs to save you.
This is a FLASH FLOOD EMERGENCY for Catawba River from Lake James
to Lake Rhodhiss. This is a PARTICULARLY DANGEROUS SITUATION. SEEK
HIGHER GROUND NOW!
HAZARD...Life-threatening flash flooding from historic rainfall
and resultant dam floodgate releases.
SOURCE...Duke Energy and Burke County Emergency Management.
IMPACT...This is a PARTICULARLY DANGEROUS SITUATION. SEEK
HIGHER GROUND NOW! Life-threatening flash-flooding of
Lake James, the Catawba River, and Lake Rhodhiss is
ongoing. Structural flooding along Lake James
continues and is developing along Lake Rhodhiss.
Downstream of Bridgewater Dam on the Catawba River,
several structrues are damaged or destroyed, with some
single-level homes submerged by floodwaters. These
floodwaters are causing numerous swift-water rescues.
Backwater effects are causing significant inundation
along tributaries, including flooding exceeding 4 ft
deep at the NC 18/US 64 bridge, blocking a primary
roadway connecting Morganton and Lenoir.
* Please stay weather aware and monitor lake levels and Duke Energy
projections closely for any changes.
* For more information on lake levels or dam releases, people are
encouraged to visit https://lakes.duke-energy.com or call
1-800-829-5253.
* Residents along the Catawba River are encouraged to stay aware of
the latest updates from Burke County by signing up for alerts at:
http://smart911.com
* McDowell County Emergency Management, Burke County Emergency
Management, Caldwell County Emergency Management, and Duke Energy
are closely monitoring these high flows and pool levels and
additional updates will be provided as new information becomes
available.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now! This is an extremely dangerous and
life-threatening situation. Do not attempt to travel unless you are
fleeing an area subject to flooding or under an evacuation order.
If you are in low-lying areas along the Catawba River you should move
to higher ground immediately.
&&
LAT...LON 3583 8188 3577 8179 3584 8164 3581 8159
3581 8146 3578 8135 3573 8139 3574 8143
3574 8159 3571 8176 3572 8194 3568 8202
3572 8206 3580 8191
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CATASTROPHIC
$$
JMP
Flash flood emergency in follow-up statement
This particular Flash flood emergency also includes the enhanced wording "Particularly Dangerous Situation".
844
WGUS71 KBOX 282143
FFSBOX
Flash Flood Statement
National Weather Service Boston/Norton MA
543 PM EDT Sun Jun 28 2020
MAC005-017-021-023-027-282300-
/O.CON.KBOX.FF.W.0003.000000T0000Z-200628T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Norfolk MA-Worcester MA-Middlesex MA-Plymouth MA-Bristol MA-
543 PM EDT Sun Jun 28 2020
...THIS IS A FLASH FLOOD EMERGENCY FOR THE TOWN OF NORWOOD AND
SURROUNDING TOWNS...
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR
NORFOLK...EASTERN WORCESTER...SOUTH CENTRAL MIDDLESEX...WEST CENTRAL
PLYMOUTH AND NORTH CENTRAL BRISTOL COUNTIES...
At 537 PM EDT, law enforcement reported heavy rain falling including
the towns of Norwood and Dedham where up to 3.5 inches have already
fallen. Flash flooding is already occurring. Some evacuations may be
necessary. Listen to local officials.
THIS IS A FLASH FLOOD EMERGENCY FOR NORWOOD AND SURROUNDING TOWNS!
This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW!
HAZARD...Life threatening flash flooding. Heavy rain producing flash
flooding.
SOURCE...Law enforcement.
IMPACT...This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER
GROUND NOW! Life threatening flash flooding of low water
crossings, small creeks and streams, urban areas, highways,
streets and underpasses.
Some locations that will experience flooding include...
Brockton, Quincy, Randolph, Franklin, Norwood, Milford, Milton,
Stoughton, Dedham, Walpole, Mansfield, Easton, Canton, Sharon,
Foxborough, Bellingham, Abington, Westwood, Holliston and Medway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. This is an extremely dangerous and
life-threatening situation. Do not attempt to travel unless you are
fleeing an area subject to flooding or under an evacuation order.
&&
LAT...LON 4210 7096 4204 7114 4203 7151 4219 7152
4223 7114 4223 7113 4224 7108
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CATASTROPHIC
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
NOCERA
See also
Flash flood guidance system
Severe weather terminology (United States)
References
Weather warnings and advisories
Flood control | Flash flood warning | [
"Chemistry",
"Engineering"
] | 3,200 | [
"Flood control",
"Environmental engineering"
] |
5,653,565 | https://en.wikipedia.org/wiki/SiRF | SiRF Technology, Inc. was a pioneer in the commercial use of GPS technology for consumer applications. The company was founded in 1995 and was headquartered in San Jose, California. Notable and founding members included Sanjai Kohli, Dado Banatao, and Kanwar Chadha. The company was acquired by British firm CSR plc in 2009, who were in turn subsequently acquired by American company Qualcomm on 13 August 2015.
SiRF manufactured a range of patented GPS chipsets and software for consumer navigation devices and systems. The chips are based on ARM controllers integrated with low-noise radio receivers to decode GPS signals at very low signal levels (typically -160dBm). SiRF chips also support SBAS to allow for differentially corrected positions.
SiRFstarIII
SiRFstarIII architecture is designed to be useful in wireless and handheld location-based services (LBS) applications, for 2G, 2.5G, 3G asynchronous networks. The SiRFstarIII family comprises the GRF3w RF IC, the GSP3f digital section, and the GSW3 software that is API compatible with GSW2 and SiRFLoc. The chips have been adopted by major GPS manufacturers, including Sony, Micro Technologies, Garmin, TomTom and Magellan.
SiRFatlas IV
SiRFatlas IV is a multifunction location system processor and is meant for entry-level Personal Navigation Devices (PNDs). The SiRFatlas IV is a cheaper version of the very popular, but rather expensive SiRFPrima platform. Has GPS/Galileo baseband, LCD touch-screen controller, video input, 10-bit ADC and a high-speed USB 2.0.
SiRFstarV
SiRFstarV chips, launched in 2012, are capable of tracking NAVSTAR, GLONASS, Galileo, Compass, SBAS, and future GNSS signals. The SiRFusion platform integrates positioning from GNSS, terrestrial radio solutions such as Wi-Fi and cellular, and MEMS sensors including accelerometers, gyroscopes, and compasses. SiRFusion can then combine this real-time information with cellular base station and Wi-Fi access point location data, ephemeribased aiding information from the CSR Positioning Center (CPC) to generate accurate and reliable position updates.
Acquisition
On 10 February 2009, UK wireless chip company CSR announced it was buying SiRF in a share deal worth $136 million.
References
External links
SiRFstar V 5e - Qualcomm
Global Positioning System
Defunct semiconductor companies of the United States
Defunct computer companies of the United States
Defunct computer hardware companies | SiRF | [
"Technology",
"Engineering"
] | 547 | [
"Global Positioning System",
"Aerospace engineering",
"Wireless locating",
"Aircraft instruments"
] |
5,653,596 | https://en.wikipedia.org/wiki/Wireless%20application%20service%20provider | A wireless application service provider (WASP) is the generic name for a firm that provides remote services, typically to handheld devices, such as cellphones or PDAs, that connect to wireless data networks. WASPs are a specific category of application service providers (ASPs), though the latter term may more often be associated with standard web services. They can also be used for wireless bridging between different types of network topologies.
Wireless networking | Wireless application service provider | [
"Technology",
"Engineering"
] | 90 | [
"Wireless networking",
"Computer networks engineering"
] |
5,653,710 | https://en.wikipedia.org/wiki/Biracks%20and%20biquandles | In mathematics, biquandles and biracks are sets with binary operations that generalize quandles and racks. Biquandles take, in the theory of virtual knots, the place that quandles occupy in the theory of classical knots. Biracks and racks have the same relation, while a biquandle is a birack which satisfies some additional conditions.
Definitions
Biquandles and biracks have two binary operations on a set written and . These satisfy the following three axioms:
1.
2.
3.
These identities appeared in 1992 in reference [FRS] where the object was called a species.
The superscript and subscript notation is useful here because it dispenses with the need for brackets. For example,
if we write for and for then the
three axioms above become
1.
2.
3.
If in addition the two operations are invertible, that is given in the set there are unique in the set such that and then the set together with the two operations define a birack.
For example, if , with the operation , is a rack then it is a birack if we define the other operation to be the identity, .
For a birack the function can be defined by
Then
1. is a bijection
2.
In the second condition, and are defined by and . This condition is sometimes known as the set-theoretic Yang-Baxter equation.
To see that 1. is true note that defined by
is the inverse to
To see that 2. is true let us follow the progress of the triple under . So
On the other hand, . Its progress under is
Any satisfying 1. 2. is said to be a switch (precursor of biquandles and biracks).
Examples of switches are the identity, the twist and where is the operation of a rack.
A switch will define a birack if the operations are invertible. Note that the identity switch does not do this.
Biquandles
A biquandle is a birack which satisfies some additional structure, as described by Nelson and Rische. The axioms of a biquandle are "minimal" in the sense that they are the weakest restrictions that can be placed on the two binary operations while making the biquandle of a virtual knot invariant under Reidemeister moves.
Linear biquandles
Application to virtual links and braids
Birack homology
References
Further reading
Knot theory
Algebraic structures
Ordered algebraic structures
Non-associative algebra | Biracks and biquandles | [
"Mathematics"
] | 522 | [
"Non-associative algebra",
"Mathematical structures",
"Mathematical objects",
"Algebraic structures",
"Ordered algebraic structures",
"Order theory"
] |
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