shaped somewhat like a vast twisted snake swallowing its own tail. it is the world ’ s largest superconductor and the only one of its type in the world. it costs the government ¥5 billion a year to run. the technology started with secret military research in the soviet union and, separately, the united states and great britain, just after world war ii. until today, the most dramatic demonstration of fusion power the world has seen has been purely destructive : the testing of hydrogen bombs set off by atomic bombs and, of course, the nuclear weapons used against the cities of hiroshima and nagasaki in august 1945. nuclear fission splits nuclei to create energy and nuclear fusion joins them to do the same thing. the first fusion device made for peaceful purposes was the tokamak, which was invented by leonid zakharov in russia in 1951. nuclear fission for peaceful use began in 1958 after a united nations conference in geneva on peaceful uses of atomic energy. since then, japan, the european union and the united states have made great efforts to modify and improve the machine. the tokamak is still widely regarded as the most promising fusion device, but there are other similar devices in the world, including one in naka, ibaraki prefecture, and at the culham centre for fusion energy near oxford, england. the tokamak has reached temperatures of 500 million degrees celsius in experiments, more than 30 times hotter than the sun. nuclear power for peaceful use has developed rapidly and there are now 400 nuclear fission power plants around the world. by contrast, the aim of constructing fusion reactors to generate electricity is still in the research and development phase. “ replicating the fusion of helium and hydrogen that powers the sun, in earthly conditions, means generating temperatures beyond 100 million degrees celsius, ” explains yamada. “ this creates plasma, the fourth state of matter after solids, liquids and gases. ” all stars, our sun included, are made of plasma. flashes of lightning are natural plasma and so too are the spectacular northern lights. artificial plasma, at much lower pressure, is present inside neon lights and plasma television screens. “ the extreme temperatures inside the lhd mean the plasma must not be allowed to touch the walls of the device. if it did, ( the walls ) would melt. ” herein lies the main difficulty with the lhd. researchers must create materials strong enough to withstand fusion at temperatures many times hotter than the sun. plasma at extremely high temperatures creates wild, unstable reactions and would irreparably damage any machine made


” herein lies the main difficulty with the lhd. researchers must create materials strong enough to withstand fusion at temperatures many times hotter than the sun. plasma at extremely high temperatures creates wild, unstable reactions and would irreparably damage any machine made to contain it that uses existing materials. yamada demonstrates this process by heating a circular fluorescent tube inside a microwave oven in a nifs display area. when he takes it out, it casts a purplish glow and is warm to the touch. he says, “ the glass walls of the tube cool the plasma. when a similar reaction occurs inside the sun, its vast gravitational pull keeps the plasma from shooting in all directions. “ once new materials have been invented, the way will be open to constructing fusion reactors able to generate electricity, using easily obtained resources that will never run out. the raw materials needed for creating plasma in fusion reactions, are lithium and deuterium, which can be extracted from seawater. ” one widespread modern use of lithium, is in mobile phones. the amount commonly used in each phone is about 0. 3 grams. together with the deuterium taken from 3 liters of seawater, a fusion reaction equivalent to 22, 000 kilowatt - hours of electric power could be created. this amount of electricity would supply a typical family in a developed country for a couple of years. or to put it another way, one liter of seawater contains enough deuterium to provide the energy content, when fused with tritium, of more than 500 liters of petroleum. fusion power plants of the future, producing a million kilowatts, would need about a tenth of a ton of deuterium and 10 tons of lithium a year as fuel. seawater covers over 70 percent of our planet and rates of extraction for hundreds of fusion reactors around the globe would never exhaust supplies. plasma inside the lhd is prevented from touching the walls by a magnetic field created inside the sinuous innards of the machine. it is done by means of a twisting, orange - hued metal alloy, wound 450 times and coiling round the outer walls of the giant tube. the coil is exposed to an electromagnetic force reaching 1, 000 tons per meter. beforehand the coil and supporting structure are cooled to minus 270 c. when cooled the structure typically shrinks 2 mm. the machine is built to tolerate a shrinkage of 2 cm. hydrogen gas is heated and injected into the machine. after reaching 10, 000 c, the hydrogen molecules disintegrate into atoms.


the latest news from academia, regulators research labs and other things of interest posted : december 7, 2009 super cool atom thermometer ( nanowerk news ) as physicists strive to cool atoms down to ever more frigid temperatures, they face the daunting task of developing new, reliable ways of measuring these extreme lows. now a team of physicists has devised a thermometer that can potentially measure temperatures as low as tens of trillionths of a degree above absolute zero. their experiment is reported in the current issue of physical review letters and highlighted with a viewpoint in the december 7 issue of physics. physicists have developed a new thermometry method suitable for measuring temperatures of ultracold atoms. ( illustration : alan stonebraker ) physicists can currently cool atoms to a few billionths of a degree, but even this is too hot for certain applications. for example, richard feynman dreamed of using ultracold atoms to simulate the complex quantum mechanical behavior of electrons in certain materials. this would require the atoms to be lowered to temperatures at least a hundred times colder than what has ever been achieved. unfortunately, thermometers that can measure temperatures of a few billionths of a degree rely on physics that doesn ' t apply at these extremely low temperatures. now a team at the mit - harvard center for ultra - cold atoms has developed a thermometer that can work in this unprecedentedly cold regime. the trick is to place the system in a magnetic field, and then measure the atoms ' average magnetization. by determining a handful of easily - measured properties, the physicists extracted the temperature of the system from the magnetization. while they demonstrated the method on atoms cooled to one billionth of a degree, they also showed that it should work for atoms hundreds of times cooler, meaning the thermometer will be an invaluable tool for physicists pushing the cold frontier. source : american physical society translate this article : check out these other trending stories on nanowerk :


very irregular, sharing features with properly random processes. this idea is colloquially known as chaos theory, and it all goes back to poincare and his oscar award. well, that ’ s the story that historians of mathematics used to tell. around 1990, however, june barrow - green found a copy of poincare ’ s prize - winning memoir in the depths of the mittag - leffler institute in sweden. she realised that when he submitted his work he had overlooked the chaotic solutions. he spotted the error before the memoir was published, and paid to have the original version destroyed and a corrected version printed. his initial oversight lay undiscovered for a century. building on poincare ’ s discovery, we now know that the three - body problem does not have simple solutions. even so, vast progress has been made on the many - body problem in special cases ; for example, when all of the bodies have the same mass. this is seldom a realistic assumption in celestial mechanics, but it is sensible for some models of elementary particles, such as electrons. in 1993, cristopher moore at the sante fe institute found a solution to the three - body problem in which the bodies play follow - my - leader along the same orbit. even more surprising is the shape of the orbit – a figure of eight. stranger than imagination in 2000, the spanish mathematician carles simo used a computer to show that this configuration is stable : it persists after small disturbances. indeed, it remains stable even when the three masses are slightly different, so, somewhere in the universe, there might be three stars of almost identical mass, chasing each other along a figure - of - eight path. the same year, douglas heggie of edinburgh university estimated that the number of such triple stars lies somewhere between one per galaxy and one per universe. the figure - of - eight orbit is a planetary dance in which the bodies return to the same positions but swap their identities, each occupying the location that the body in front of it has vacated. this kind of orbit is called a choreography. using a computer, simo has found a huge number of choreographies, which can involve a large number of bodies. the solar system is, was, and will be, far stranger than we imagine. consider the comet oterma. a century ago, oterma ’ s orbit was well outside that of jupiter. after a close encounter with the giant planet, its orbit shifted inside that of jupiter. after another close encounter, it switched


the nobel prize in physics 2001 eric a. cornell, wolfgang ketterle, carl e. wieman bose - einstein condensation in a dilute gas ; the first 70 years and some recent experiments eric a. cornell held his nobel lecture december 8, 2001, at aula magna, stockholm university. he was presented by professor mats jonson, chairman of the nobel committee for physics. summary : fundamental ideas behind creating bose - einstein condensate ( bec ) in a gas are outlined. starting with heisenberg ' s uncertainty principle, the formation of bose - einstein condensate ( bec ) is explained as occurring when the interatomic spacing is comparable to thermal de broglie wavelength. the conditions for creating bec in a gas are described, and the necessary ingredients for creating bec in a gas are listed in an " ultra cold alkali tool kit ". copyright © nobel web ab 2001 credits : kamera communications ( webcasting ) read the nobel lecture pdf 447 kb copyright © the nobel foundation 2001 from les prix nobel. the nobel prizes 2001, editor tore frangsmyr, [ nobel foundation ], stockholm, 2002 mla style : " eric a. cornell - nobel lecture : bose - einstein condensation in a dilute gas ; the first 70 years and some recent experiments ". nobelprize. org. 22 may 2013 http : / / www. nobelprize. org / nobel _ prizes / physics / laureates / 2001 / cornell - lecture. html


using an ultra - bright electron source, scientists at the university of toronto have recorded atomic motions in real time, offering a glimpse into the very essence of chemistry and biology at the atomic level. their recording is a direct observation of a transition state in which atoms undergo chemical transformation into new structures with new properties. using a new tool called a quantum simulator — based on a small - scale quantum computer —... a massive telescope buried in the antarctic ice has detected 28 extremely high - energy... a fried breakfast food popular in spain provided the inspiration for the development of doughnut - shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics, and materials. the doughnut - shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. the massive ball of iron sitting at the center of earth is not quite as " rock - solid " as has been thought, say two stanford university mineral physicists. by conducting experiments that simulate the immense pressures deep in the planet ' s interior, the researchers determined that iron in earth ' s inner core is only about 40 % as strong as previous studies estimated. graphene has dazzled scientists ever since its discovery more than a decade ago. but one long - sought goal has proved elusive : how to engineer into graphene a property called a band gap, which would be necessary to use the material to make transistors and other electronic devices. new findings by massachusetts institute of technology researchers are a major step toward making graphene with this coveted property. with the hand of nature trained on a beaker of chemical fluid, the most delicate flower structures have been formed in a harvard university laboratory — and not at the scale of inches, but microns. these minuscule sculptures, curved and delicate, don ' t resemble the cubic or jagged forms normally associated with crystals, though that ' s what they are. rather, fields of flowers seem to bloom from the surface of a submerged glass slide. a new joint innovation by the national physical laboratory and the university of cambridge could pave the way for redefining the ampere in terms of fundamental constants of physics. the world ' s first graphene single - electron pump provides the speed of electron flow needed to create a new standard for electrical current based on electron charge. described as the " most beautiful experiment in physics, " richard feynman emphasized how the diffraction of individual particles at a grating is an unambiguous demonstration of


needed to create a new standard for electrical current based on electron charge. described as the " most beautiful experiment in physics, " richard feynman emphasized how the diffraction of individual particles at a grating is an unambiguous demonstration of wave - particle duality and contrary to classical physics. a research team recently used carefully made fluorescent molecules and nanometric detection accuracy to provide clear and tangible evidence of the quantum behavior of large molecules in real time. bubble baths and soapy dishwater and the refreshing head on a beer : these are foams, beautiful yet ephemeral as the bubbles pop one by one. now, a team of researchers has described mathematically the successive stages in the complex evolution and disappearance of foamy bubbles, a feat that could help in modeling industrial processes in which liquids mix or in the formation of solid foams such as those used to cushion bicycle helmets. an international team of physicists has found the first direct evidence of pear - shaped nuclei in exotic atoms. the findings could advance the search for a new fundamental force in nature that could explain why the big bang created more matter than antimatter — a pivotal imbalance in the history of everything. from powerful computers to super - sensitive medical and environmental detectors that are faster, smaller, and use less energy — yes, we want them, but how do we get them? in research that is helping to lay the groundwork for the electronics of the future, university of delaware scientists have confirmed the presence of a magnetic field generated by electrons which scientists had theorized existed, but that had never been proven until now. physicists working with optical tweezers have conducted work to provide an all - in - one guide to help calculate the effect the use of these tools has on the energy levels of atoms under study. this effect can change the frequency at which atoms emit or absorb light and microwave radiation and skew results ; the new findings should help physicists foresee effects on future experiments. physicists in switzerland have demonstrated one of the quintessential effects of quantum optics — known as the hong - ou - mandel effect — with microwaves, which have a frequency that 100, 000 times lower than that of visible light. the experiment takes quantum optics into a new frequency regime and could eventually lead to new technological applications. the allure of personalized medicine has made new, more efficient ways of sequencing genes a top research priority. one promising technique involves reading dna bases using changes in electrical current as they are threaded through a nanoscopic hole. now, a


technological applications. the allure of personalized medicine has made new, more efficient ways of sequencing genes a top research priority. one promising technique involves reading dna bases using changes in electrical current as they are threaded through a nanoscopic hole. now, a team led by university of pennsylvania physicists has used solid - state nanopores to differentiate single - stranded dna molecules containing sequences of a single repeating base. an international research team led by astronomers from the max planck institute for radio astronomy used a collection of large radio and optical telescopes to investigate in detail a pulsar that weighs twice as much as the sun. this neutron star, the most massive known to date, has provided new insights into the emission of gravitational radiation and serves as an interstellar laboratory for general relativity in extreme conditions. using uniquely sensitive experimental techniques, scientists have found that laws of quantum physics — believed primarily to influence at only sub - atomic levels — can actually impact on a molecular level. the study shows that movement of the ring - like molecule pyrrole over a metal surface runs counter to the classical physics that govern our everyday world. in a process comparable to squeezing an elephant through a pinhole, researchers at missouri university of science and technology have designed a way to engineer atoms capable of funneling light through ultrasmall channels. their research is the latest in a series of recent findings related to how light and matter interact at the atomic scale. cancer cells that can break out of a tumor and invade other organs are more aggressive and nimble than nonmalignant cells, according to a new multi - institutional nationwide study. these cells exert greater force on their environment and can more easily maneuver small spaces. one simple phenomenon explains why practical, self - sustaining fusion reactions have proved difficult to achieve : turbulence in the superhot, electrically charged gas, called plasma, that circulates inside a fusion reactor can cause the plasma to lose much of its heat. this prevents the plasma from reaching the temperatures needed to overcome the electrical repulsion between atomic nuclei. until now. lawrence berkeley national laboratory ’ s sound - restoration experts have done it again. they ’ ve helped to digitally recover a 128 - year - old recording of alexander graham bell ’ s voice, enabling people to hear the famed inventor speak for the first time. the recording ends with bell saying “ in witness whereof, hear my voice, alexander graham bell. ” researchers at university of california, santa barbara in collaboration with colleagues at the ecole polytechnique in france, have conclusively identified auger recombination


bell saying “ in witness whereof, hear my voice, alexander graham bell. ” researchers at university of california, santa barbara in collaboration with colleagues at the ecole polytechnique in france, have conclusively identified auger recombination as the mechanism that causes light - emitting diodes ( leds ) to be less efficient at high drive currents. a harvard university - led team of researchers has created a new type of nanoscale device that converts an optical signal into waves that travel along a metal surface. significantly, the device can recognize specific kinds of polarized light and accordingly send the signal in one direction or another. the planet - hunting kepler telescope has discovered two planets that seem like ideal places for some sort of life to flourish. according to scientists working with the nasa telescope, they are just the right size and in just the right place near their star. the discoveries, published online thursday, mark a milestone in the search for planets where life could exist. throughout decades of research on solar cells, one formula has been considered an absolute limit to the efficiency of such devices in converting sunlight into electricity : called the shockley - queisser efficiency limit, it posits that the ultimate conversion efficiency can never exceed 34 % for a single optimized semiconductor junction. now, researchers have shown that there is a way to blow past that limit. scientists in australia have recently demonstrated that ultra - short durations of electron bunches generated from laser - cooled atoms can be both very cold and ultra - fast. the low temperature permit sharp images, and the electron pulse duration has a similar effect to shutter speed, potentially allowing researchers to observe critical but quick dynamic processes, such as the picosecond duration of protein folding. a university of missouri engineer has built a system that is able to launch a ring of plasma as far as two feet. plasma is commonly created in the laboratory using powerful electromagnets, but previous efforts to hold the super - hot material through air have been unsuccessful. the new device does this by changing how the magnetic field around the plasma is arranged. physicists operating an experiment located half a mile underground in minnesota reported this weekend that they have found possible hints of dark - matter particles. the cryogenic dark matter search experiment has detected three events with the characteristics expected of dark matter particles.


the conviction that nothing exists — it is possible to name a set that has no elements. ) david hilbert, the dean of mathematics at the dawn of the century, had thought that such a reduction was possible and posed it as a challenge. but hilbert was doomed to failure here. the reason for this, at a basic level, is self - reference. sentences like “ this sentence is false ” turn out to pose a nasty set of technical challenges that make it impossible to fully express mathematical knowledge as a consequence of logical axioms — things that are held, on their face, to be true. godel, an austrian logician who would become a good friend of albert einstein ’ s after both of them settled in princeton, proved this in a 1931 paper, whose consequences were later strengthened by turing. godel ’ s incompleteness theorem says that in any sufficiently strong logical system ( meaning one that is rich enough to express mathematics ), it is impossible to prove that the axioms — the assumptions — of the system do not lead to a contradiction. the importance of godel ’ s incompleteness theorems for artificial intelligence is something that remains hotly debated. one school of thought, as ernest nagel and james newman wrote in 1956, holds that incompleteness means “ that the resources of the human intellect have not been, and cannot be, fully formalized, and that new principles of demonstration forever await invention and discovery. ” the other school of thought says, basically, “ don ’ t worry about it! ” the best - known recent exponent of this school is ray kurzweil, who claims, without much evidence, that “ there is an essential equivalence between a computer and the brain. ” kurzweil ’ s overheated triumphalism aside ( he seems determined to prove that careful thought is not necessary to be human by displaying a tremendous lack of care himself ), this is not a question that we need to resolve to say something about what current progress in artificial intelligence is doing to the idea of truth. even if nagel and newman are right and human intellect cannot be fully formalized, computer scientists have come a long way since john mccarthy first enunciated the aim of formalizing common sense. computer scientists have worked to come up with formal descriptions of the everyday world. here is a short list, taken from the stanford encyclopedia of philosophy of some of scenarios they ’ ve tried to encode : the baby scenario, the bus ride scenario, the chess board scenario, the ferryboat connection scenario, the furniture assembly


world. here is a short list, taken from the stanford encyclopedia of philosophy of some of scenarios they ’ ve tried to encode : the baby scenario, the bus ride scenario, the chess board scenario, the ferryboat connection scenario, the furniture assembly scenario, the hiding turkey scenario, the kitchen sink scenario, the russian turkey scenario, the stanford murder mystery, the stockholm delivery scenario, the stolen car scenario, the stuffy room scenario, the ticketed car scenario, the walking turkey scenario, and the yale shooting anomaly. let ’ s take the last of these — the yale shooting anomaly, which aims to formally codify the fact that an unloaded shotgun, if loaded and then shot at a person, would kill the person. classical logic dealt with things like “ 1 + 1 = 2 ” which are true, ( or false, like 1 = 0 ) for all time. they were true, are true, and always will be true. it doesn ’ t allow for things to happen. but to encode common - sense knowledge, computer scientists need a way to allow for events to take place. they also need ways to encode spatial locations. some of this had been worked out in a rigorous but limited way, in what philosophers call modal logic, which was first enunciated by c. i. lewis in 1918. but modal logic was too limited for computer scientists to use in semireal world systems. in the languages that computer scientists have come up with, as in the yale shooting anomaly, they were unable to preclude the possibility that the shotgun would spontaneously unload itself. it ’ s not that computer scientists think that that will happen ; it ’ s that they struggle to formalize how it can ’ t. ( since the yale shooting anomaly was first stated in 1986, many solutions have been proposed, but it remains an area of research. ) a central challenge computer scientists face is what ’ s called the ramification problem : how to codify that fact that if i walk into a room, my shirt does, too. this is paralleled by the “ frame problem, ” first enunciated by mccarthy in 1969, which is the “ problem of efficiently determining which things remain the same in a changing world. ” these problems are considerably harder than careless cheerleaders like kurzweil make them out to be. the central result of logicians in the 20th century was that, in the end, it will always be necessary to extend your axioms — things you just assume to be true without


polishing characteristics and problems pyrrhotite, chalcopyrite, magnetite and pentlandite. kambalda, western australia the section has been partially polished with 6µm diamond paste. individual grains of pyrrhotite ( brown ) are clearly seen due to differential polishing. crystals in some orientations still retain many polishing pits ( black ) whereas others are well polished. chalcopyrite ( yellow, centre bottom ) and magnetite ( light grey, bottom right ) are present. pentlandite ( pale yellow - brown, centre right and close to a diagonal fracture ) has higher reflectance than pyrrhotite and is just visible within the largest pyrrhotite crystal as small pentlandite flame - like exsolution bodies along a fracture - dark grey area ( bottom right ) is silicate, black areas are polishing pits. coarse features, especially grain boundaries, are well shown after initial polishing, but fine features are still difficult to see. llmenite and haematite. kimberlite pipe. unknown provenance this section has been polished with 1µm diamond paste, but shows extensive plucking. host magnesium - rich ilmenite crystals ( brown ) carry lath - shaped haematite exsolution bodies ( blue - grey ). plucked areas ( black ) have the same size, shape and orientation as the haematite, suggesting that it has been preferentially removed. if more than one phase is plucked in a section then it becomes difficult to estimate modal percentages. bornite, stromeyerite, chalcocite, pyrite and tetrahedrite group mineral. unknown provenance this section has been polished with ¼ µm diamond paste. although the section is scratch - free has enormous relief and hence shows strong shadows about the harder phases. euhedral to subhedral pyrite ( pale yellow, high reflectance ), a tetrahedrite group mineral ( light grey, centre and top centre ) and quartz ( dark grey, bottom centre ) show high relief against the softer copper and silver sulphides. bornite ( brown - red, left ) has an symplectite - like intergrowth with, and inclusions of, chalcocite ( light blue ). stromeyerite ( light lilac - grey, centre right ) also is complexly intergrown with chalcocite. although relief accentuates the symplectite texture of the softer phases, they remain poorly polished


w3c working draft 23 january 2003, http : / / www. w3. org / tr / rdf - concepts [ pascal1 ] " what meaning means ", fabian pascal http : / / www. inconcept. com / jcm [ pascal2 ] " something to call one ' s own ", fabian pascal, http : / / www. dbdebunk. com / fp6a. htm [ riggs ] " xml and free text ", k. r. riggs, journal of the american society for information science and technology, v53, n 6, 2002, 526 - 528 [ schema ] xml schema, w3c org, www. w3. org / xml / schema [ sowa ] knowledge representation, john f. sowa, brooks cole, 2000 [ xirql ] xirql : a query language for information retrieval in xml documents, fuhr, n. großjohann, k. http : / / www. is. informatik. uni - duisburg. de / bib / xml / fuhr _ grossjohann _ 01. html. en [ xml - ql ] xml - ql : a query language for xml, alin deutsch, mary fernandez, daniela florescu, alon levy, dan suciu, http : / / www. w3. org / tr / note - xml - ql / # issues this article previously appeared in the journal of conceptual modeling, may 2003. ken roger riggs, ph. d - ken roger riggs, ph. d. is a computer scientist and a professor of cis at florida a & m university. his degrees are in philosophy ( indiana university ), computer science ( u. of central florida ) and electrical and computer engineering ( u. of miami ). he has been involved in a mix of practice, research and teaching since 1976. his interest in models is both practical and pedagogical. his recent published work includes papers on ai, databases, datamining and xml marking. other recent publications address conceptual modeling related issues in software engineering ( refactoring ) and programming languages.


a material made from fibers or thread by weaving, knitting, felting etc. as any cloth. 1. to make, build or construct by assembling parts or manufacturing. 2. to make from raw material. external front of a building that faces the street or courtyard and is usually used to describe bigger, elegant buildings. fasade materials include wood, brick, glass, masonry, aluminum, etc. 1. the side of a wall covering that faces away from the framing ; for example in an a - b plywood panel, the face would be the a side. 2. an exterior, exposed surface on a structure. 3. any surface of a thing. 4. the outward appearance of anything. the dollar amount, shown on a document. exterior decorative surface, which is made of brick that is not rendered, painted or plastered and is made of various brick materials, including clay, to give a desired effect. applies to the direction of the grain on the face of a veneer - faced panel, which is also called the long dimension of the panel. since the greatest strength and firmness is parallel to the face grain, it is normal to run the face grain across the supports. hardening process for the surface of materials. as an example, the hardening of carbon steel is accomplished by first heating the steel to approximately 1200 degrees f. and then it is immersed in powdered carbon. when some of the carbon is absorbed into the molecular structure of the steel, the surface or face of the steel is hardened. also referred to as the face ply, it is the outer layer when there are two or more layers. face line lines that are made of strong string, which is stretched out and attached to staked boards, so that masons can follow the straightness of it when building masonry walls. nails, which are hammered at right angles ( perpendicular ) to the work surface. also called direct nailing. the side of the material where the weld was applied, which has the exposed weld. face plate holds the work to be turned on a lathe. the plate is then fastened to the lathe headstock, which is the part of the lathe that turns the work. also referred to as the face layer, it is the outer layer when there are two or more layers. additional weld material, which is added to the face of the weld. front of a concrete block. coverings, designed to protect the entire face of a worker when a sander, grinder, etc.


are two or more layers. additional weld material, which is added to the face of the weld. front of a concrete block. coverings, designed to protect the entire face of a worker when a sander, grinder, etc. are being used. a transparent eye panel allows the worker to be protected from small particles, which are being thrown, while being able to see. the dollar amount shown on a document. measurement of the air velocity as measured at the face of the inlet or outlet in an hvac system. the outer veneer on a piece of plywood. the front wall of a structure or, alternately, a retaining wall. masonry structure that has different types of material as backing and facing, such as brick on concrete, bonded together. veneer covered structural wall. real estate professional who aids in a transaction but does not have an agency relationship with that party and can be known as an intermediary or transaction broker. 1. ease of doing or making ; absence of difficulty. 2. a building or special room, constructed for a specific function. 1. covering of contrasting material to decorate or protect a building ; a finished wall surface. 2. smoothing ; finishing. specifically made brick, in a special color or texture, for the outside or facing wall of a building. a reproduction or exact copy or architecturally a reproduction of a building style. alternately, the electronic transfer of an exact image of a document or picture, referred to as a " fax ". the purchase of the accounts receivable of a business or alternately, taking the accounts receivable of a business as collateral for a loan. the ratio of the maximum strength of a piece of material or a part to the probably maximum load to be applied to it. if a maximum of 2, 000 pounds can be tolerated, a load of 500 pounds will have a 4 to one factor of safety. the edge of any fabricated item that has been prepared in a factory, such as the long edge of wallboard panels, coming from a factory covered with paper. fade. 1. to become less distinct. to lose color or brilliance. 2. to disappear slowly. to wane. also spelled faggot, the term refers to a bundle of sticks or branches to be used for fuel, or alternately, a bundle of iron or steel pieces to be hammered or rolled, at welding temperature, into bars. temperature measurement, named after its discoverer daniel fahrenheit 1686 - 1736, in which 32 degrees is the freezing point and


generating and guiding laser signals. they also helped determine the properties of quantum dot materials. quantum dots, which emit the light that creates lasers, are nanometer - size semiconductor structures in which the presence or absence of a quantum electron can be used to store information. " we tried to modify the bandgap and lasing wavelength in order to control the optical properties of the quantum - dot structures, " says soo, who hopes to continue her work in the area by setting up the photoluminescent system that can characterize this nano - material structure. using labview software, negro and oh integrated the new equipment to a central computer, then merged data from two or more machines so that the experimental results could be plotted in one graph on the computer screen. " without the computer, it would have taken an entire day to generate a graph, " says negro. " with the computer, we generated the same graph in two seconds. " in addition to gaining valuable experience in the lab, the students realized other benefits from their summer internship. " this opened a wide variety of options for me, " says negro, who hopes to take advantage of the university ' s presidential scholarship program, which offers a tuition - free fifth year of study to students with a 3. 75 undergraduate gpa. " working in a lab requires a lot of patience and dedication, " says oh. " it has enabled me to see what it would be like to be a graduate student. it has also shown me what i ' m lacking, and that will help me know what electives to choose the next two years. " posted on wednesday, december 01, 2004


brookhaven national laboratory has what is currently one of the highest energy particle accelerators on the planet. the relativistic heavy ion collider ( rhic ) hosts collisions between the nuclei of gold atoms that are moving at roughly 99 percent of the speed of light, creating a quark soup similar to the one that existed immediately after the big bang. but the scientists running the experiments started noticing something funny about the data : instead of expanding evenly outward, the collision debris were ellipsoidal ( think a 3 - d ellipse ). what was even stranger was that this sort of behavior had already been described, for a gas of lithium atoms at the opposite end of the temperature spectrum, at a fraction of a microkelvin. as these groups were talking about a collaboration, things got stranger still when string theorists started citing this work, since the behavior had already been predicted through their work — a fact that the physicists weren ' t aware of until a science reporter called to ask what they thought about it. the tale of this unlikely collaboration unfolded at the american association for the advancement of science meeting, where the introductory remarks described just how far apart these systems are. in terms of temperature, the rhic and chilled lithium differ by 19 orders of magnitude ( that ' s a factor of 1019 ). when it comes to density, the difference is an astonishing 25 orders of magnitude. meanwhile, the bit of string theory that describes the normal, four - dimensional ( 3 - d + time ) behavior of these systems can be predicted by modeling a four - dimensional sphere wrapped around a five dimensional black hole. quantum viscosity runs hot and cold the cold atomic cloud is probably easiest to understand, although john thomas of duke, who does the work, claimed that, when dragged to wine tastings with his wife ' s friends, " i wait until everyone ' s sufficiently drunk before explaining what we do. " his short description is that he makes bowls of light ; in principle, the first steps in his system involve the sort of laser cooling that our chris lee has described in the past. this can only get things down to a bit under a kelvin above absolute zero, but thomas then loosens the laser trap, and a few atoms evaporate off, taking most of the remaining heat with them. the end result is an atomic cloud at one - tenth of a microkelvin. the 6li atoms that he uses have up and down spins that form an analog of the cooper pairs of electrons that cause high - temperature supercondu


with them. the end result is an atomic cloud at one - tenth of a microkelvin. the 6li atoms that he uses have up and down spins that form an analog of the cooper pairs of electrons that cause high - temperature superconductivity, so his system allows theorists to test some of their ideas in an accessible experimental system. but it also has interesting properties when in a magnetic field. at a specific magnetic field strength, the interactions between the paired atoms start to go asymptotic and, when at a very precise point, the interactions vanish and quantum effects dominate. when the laser trap is released again, the atoms expand elliptically, displaying essentially the smallest amount of quantum viscosity possible. because the system is experimentally possible, they were able ( on the advice of string theorists — more on that below ) to measure both the viscosity and entropy, and found that they were related directly to one divided by four?. out at the other end of the temperature spectrum, the collisions in the rhic were producing what brookhaven ' s barbara jacack termed " quark soup. " in normal matter, quarks interact by exchanging gluons with a limited number of partners. but, at the densities that exist immediately after these collisions, quarks can exchange multiple gluons with multiple partners, leading to longer - range interactions that are more similar to those in a liquid. two aspects of the behavior seen by rhic ' s detectors, however, were a bit surprising. the first is the ellipsoidal expansion that marks the behavior of perfect quantum liquids that we mentioned above. the second is that, although radiation can pass across the small cluster of quark soup, the actual quarks, it appeared, could not. jacack likened the fact that even the heavy charm quark didn ' t make it across the collision to a set of bowling pins stopping an incoming ball. like thomas, talking to string theorists allowed jacack and her team to look for some specific properties — in this case, shock waves of a particular type — of the quark soup. so far, it ' s looking like they ' re there. rhic is about to undergo a retrofit that should make it easier to study this, and the stimulus package may have some money for the doe that could accelerate the work. the theory needs a five - dimensional black hole, but reality may not clifford johnson of usc then spoke about how a specific application of string theory helped tie everything together


, and the stimulus package may have some money for the doe that could accelerate the work. the theory needs a five - dimensional black hole, but reality may not clifford johnson of usc then spoke about how a specific application of string theory helped tie everything together. as he described it, quantum chromodynamics ( qcd ) works very well at describing the interactions of a limited number of particles, and its successes in the early 1970s caused researchers to abandon an earlier version of string theory. but qcd doesn ' t work that well at the densities seen in the rhic, where ensembles of particles have emergent behavior — as johnson noted, a single water molecule isn ' t wet ; that ' s a property that emerges from a population of water molecules. and this, along with a few other vexing problems, has allowed string theory back in the game. " string theory, " johnson said, " having failed to explain something, got resurrected a few years on and was used to explain everything, " or at least provide a quantum description of gravity. he got interested in the problem of describing quantum black holes, which are far smaller than the macroscopic ones we ' ve observed in space. based on their emission of quantum radiation, they have to have an internal structure, one that our lack of a quantum gravity is preventing us from probing. ( during the questions, it became clear that johnson is one of the few people hoping that the lhc does spawn a small black hole. ) it turns out, using the math of string theory, it ' s easy to examine a five - dimensional black hole simply by wrapping a four - dimensional sheet around it. when you do that, however, a lot of three - dimensional qcd behavior pops out of the equations — " the bugs of string theory become features, " as johnson put it. in the extra dimensions, gravitons get pulled towards, and then bounce off, the black hole, undergoing interference as they do. that interference apparently describes the behavior seen in both of these real - world systems. johnson was emphatic that this doesn ' t mean that the experiments that have used these string theory models are a test of the theory ; rather, it means that the predictions of string theory are being used to guide experiments, which is a measure of its utility. as for whether there ' s really an extradimensional black hole tucked away in these conditions, johnson described himself as " agnostic. " it may be possible, he said, to find a way to describe this


an efficient solar harvest solar power could be harvested more efficiently and transported over longer distances using tiny molecular circuits based on quantum mechanics, according to research inspired by new insights into natural photosynthesis. incorporating the latest research into how plants, algae and some bacteria use quantum mechanics to optimize energy production via photosynthesis, ucl scientists have set out how to design molecular circuitry that is 10 times smaller than the thinnest electrical wire in computer processors. published in nature chemistry, the report discusses how tiny molecular energy grids could capture, direct, regulate and amplify raw solar energy. solar fuel production is all about energy from light being absorbed by an assembly of molecules ; this electronic excitation is subsequently transferred to a suitable acceptor. for example, in photosynthesis, antenna complexes capture sunlight and direct the energy to reaction centers that then carry out the associated chemistry. in photosynthesis chlorophyll captures sunlight and directs the energy to special proteins that help make oxygen and sugars. this is no different in principle than a solar cell. in natural systems energy from sunlight is captured by colored molecules called dyes or pigments, but it is only stored for a billionth of a second. this leaves little time to route the energy from pigments to the molecular machinery that produces fuel or electricity. the key to transferring and storing energy very quickly is to harness the collective quantum properties of antennae, which are made up of just a few tens of pigments. recent studies have identified quantum coherence and entanglement between the excited states of different pigments in the light - harvesting stage of photosynthesis. although this stage of photosynthesis is highly efficient, it remains unclear exactly how or if these quantum effects are relevant. dr alexandra olaya - castro, co - author of the paper from ucl ’ s department of physics and astronomy said : “ on a bright sunny day, more than 100 million billion red and blue colored photons strike a leaf each second. ” “ under these conditions plants need to be able to both use the energy that is required for growth but also to get rid of excess energy that can be harmful. transferring energy quickly and in a regulated manner are the two key features of natural light harvesting systems. “ by assuring that all relevant energy scales involved in the process of energy transfer are more or less similar, natural antennae manage to combine quantum and classical phenomena to guarantee efficient and regulated capture, distribution and storage of the sun ’ s energy. ” summary of lessons from nature about concentrating and


the study of motion is often called kinematics. we will begin our study with one dimensional kinematics. we will later expand to 2 and 3 dimensional kinematics after we have studied vectors. we can give the position of an object in relation to a reference point. there are a number of variables we can use for position, such as x, d, or s. the official metric unit for position is the meter ( abbreviated m ). the meter was first defined in terms of the circumference of the earth on a meridian passing through paris. it is now defined in terms of the speed of light. when working with other scales, it might be convenient to use other metric units such as the nanometer ( nm ), the centimeter ( cm ), and the kilometer ( km ). we will often use exponential notation. exponential notation is convenient for expressing very large and small numbers. for instance, 12, 300 would be expressed as 1. 23 x 10, 000 or 1. 23 x 104 so 3. 14 km = 3140 m = 3. 14 x 103 m for small numbers, 0. 000345 = 3. 45 x 10 - 4 a micrometer, 1 μm = 10 - 6 m the width of a human hair on average is 10 μm. this would be 10 x 10 - 6 m. the wavelength of a helium - neon laser is 633 nm = 633 x 10 - 9 m = 6. 33 x 10 - 7 m the common metric units are given in powers or 3. the kilometer is 1000 m. although the 100 centimeters = 1 meter it is not actually a common unit. 1 millimeter = 1mm = 10 - 3 m 1 micrometer = 1um = 10 - 6 m 1 nanometer = 1nm = 10 - 9 m 1 picometer = 1pm = 10 - 12 m 1 femotometer = 1fm = 10 - 15 m also known as a fermi except for kilometer, we often do not use the larger metric prefixes for distance. but they are used for frequencies and other units in physics. 1 kilometer = 1 km = 1000 m = 103 m megameter = 1mm = 106 m gigameter = 1gm = 109 m terrameter = 1 tm = 1012 m common british imperial units for measuring distance include the inch, the foot, the yard, and the mile. an easy way to remember the conversion from meters to miles can be remembered in terms of track and field. the loop in a track


5 m due east. as displacement has both a magnitude and a direction, we call it a vector. we measure time in seconds. we will use the variable t for time. the elapsed time for a certain action would be δt. the greek letter delta, δ, is used to represent a change in a quantity. if we are talking about a reoccurring event ( such as the orbit of the earth around the sun ) we talk about the period of time t, with a capitol t. for longer periods of time we will often use the conventional minutes, hours, days, or years. for shorter periods of time will often use exponential notation or may use milliseconds, microseconds, picoseconds, or femtoseconds. for instance, chemical reactions may often take place on the picosecond timescale. just as when you dance under a strobe like at a cool school dance you can see your movements in stop action. scientists use pulsed lasers with picosecond and femtosecond pulses to examine dynamics at the molecular level. speed and velocity building on changes in position and changes in time, we can examine the rate at which these changes in position take place. how fast are we moving? you probably use the terms speed and velocity interchangeably in your everyday vernacular, but in physics they have distinct meanings. speed is a scalar and has no direction. speed can be defined as speed = distance / elapsed time velocity is a vector. we could consider velocity to be speed in a given direction. to calculate the average velocity over a period of time, we use displacement and elapsed time. where v is velocity, x is position, t is time. the greek letter delta, δ, means a change in a quantity, such as the change in position or the change in time. the bar over the velocity v means the terms in averaged. for instance, δx = xf – xo, or the change is position equals the difference of the final position and the original positions. our first set of problems will involve the above kinematic equation. problem solving method when solving physics problems, it is useful to follow a simple problem solving strategy. although at first, it may be easy to solve some problems in your head, by following this strategy you will develop good problem solving habits. just as you must develop good habits by brushing your teeth every day, you should attempt to follow the following methodology for solving physics problems. the


general chemistry / periodicity and electron configurations blocks of the periodic table the periodic table does more than just list the elements. the word periodic means that in each row, or period, there is a pattern of characteristics in the elements. this is because the elements are listed in part by their electron configuration. the alkali metals and alkaline earth metals have one and two valence electrons ( electrons in the outer shell ) respectively. these elements lose electrons to form bonds easily, and are thus very reactive. these elements are the s - block of the periodic table. the p - block, on the right, contains common non - metals such as chlorine and helium. the noble gases, in the column on the right, almost never react, since they have eight valence electrons, which makes it very stable. the halogens, directly to the left of the noble gases, readily gain electrons and react with metals. the s and p blocks make up the main - group elements, also known as representative elements. the d - block, which is the largest, consists of transition metals such as copper, iron, and gold. the f - block, on the bottom, contains rarer metals including uranium. elements in the same group or family have the same configuration of valence electrons, making them behave in chemically similar ways. causes for trends there are certain phenomena that cause the periodic trends to occur. you must understand them before learning the trends. effective nuclear charge the effective nuclear charge is the amount of positive charge acting on an electron. it is the number of protons in the nucleus minus the number of electrons in between the nucleus and the electron in question. basically, the nucleus attracts an electron, but other electrons in lower shells repel it ( opposites attract, likes repel ). shielding effect the shielding ( or screening ) effect is similar to effective nuclear charge. the core electrons repel the valence electrons to some degree. the more electron shells there are ( a new shell for each row in the periodic table ), the greater the shielding effect is. essentially, the core electrons shield the valence electrons from the positive charge of the nucleus. electron - electron repulsions when two electrons are in the same shell, they will repel each other slightly. this effect is mostly canceled out due to the strong attraction to the nucleus, but it does cause electrons in the same shell to spread out a little bit. lower shells experience this effect more because they are smaller and allow the electrons to interact more. coulomb ' s


canceled out due to the strong attraction to the nucleus, but it does cause electrons in the same shell to spread out a little bit. lower shells experience this effect more because they are smaller and allow the electrons to interact more. coulomb ' s law coulomb ' s law is an equation that determines the amount of force with which two charged particles attract or repel each other. it is, where is the amount of charge ( + 1e for protons, - 1e for electrons ), is the distance between them, and is a constant. you can see that doubling the distance would quarter the force. also, a large number of protons would attract an electron with much more force than just a few protons would. trends in the periodic table most of the elements occur naturally on earth. however, all elements beyond uranium ( number 92 ) are called trans - uranium elements and never occur outside of a laboratory. most of the elements occur as solids or gases at stp. stp is standard temperature and pressure, which is 0° c and 1 atmosphere of pressure. there are only two elements that occur as liquids at stp : mercury ( hg ) and bromine ( br ). bismuth ( bi ) is the last stable element on the chart. all elements after bismuth are radioactive and decay into more stable elements. some elements before bismuth are radioactive, however. atomic radius leaving out the noble gases, atomic radii are larger on the left side of the periodic chart and are progressively smaller as you move to the right across the period. conversely, as you move down the group, radii increase. atomic radii decrease along a period due to greater effective nuclear charge. atomic radii increase down a group due to the shielding effect of the additional core electrons, and the presence of another electron shell. ionic radius for nonmetals, ions are bigger than atoms, as the ions have extra electrons. for metals, it is the opposite. extra electrons ( negative ions, called anions ) cause additional electron - electron repulsions, making them spread out farther. fewer electrons ( positive ions, called cations ) cause fewer repulsions, allowing them to be closer. | ionization energy is the energy required to strip an electron from the atom ( when in the gas state ). ionization energy is also a periodic trend within the periodic table organization. moving left to right within a period or upward within a group, the first ionization energy generally increases. as the


an electron from the atom ( when in the gas state ). ionization energy is also a periodic trend within the periodic table organization. moving left to right within a period or upward within a group, the first ionization energy generally increases. as the atomic radius decreases, it becomes harder to remove an electron that is closer to a more positively charged nucleus. ionization energy decreases going left across a period because there is a lower effective nuclear charge keeping the electrons attracted to the nucleus, so less energy is needed to pull one out. it decreases going down a group due to the shielding effect. remember coulomb ' s law : as the distance between the nucleus and electrons increases, the force decreases at a quadratic rate. it is considered a measure of the tendency of an atom or ion to surrender an electron, or the strength of the electron binding ; the greater the ionization energy, the more difficult it is to remove an electron. the ionization energy may be an indicator of the reactivity of an element. elements with a low ionization energy tend to be reducing agents and form cations, which in turn combine with anions to form salts. electron affinity | electron affinity is the opposite of ionization energy. it is the energy released when an electron is added to an atom. electron affinity is highest in the upper left, lowest on the bottom right. however, electron affinity is actually negative for the noble gasses. they already have a complete valence shell, so there is no room in their orbitals for another electron. adding an electron would require creating a whole new shell, which takes energy instead of releasing it. several other elements have extremely low electron affinities because they are already in a stable configuration, and adding an electron would decrease stability. electron affinity occurs due to the same reasons as ionization energy. electronegativity is how much an atom attracts electrons within a bond. it is measured on a scale with fluorine at 4. 0 and francium at 0. 7. electronegativity decreases from upper right to lower left. electronegativity decreases because of atomic radius, shielding effect, and effective nuclear charge in the same manner that ionization energy decreases. metallic character metallic elements are shiny, usually gray or silver colored, and good conductors of heat and electricity. they are malleable ( can be hammered into thin sheets ), and ductile ( can be stretched into wires ). some metals, like sodium, are soft and can be cut with a knife. others, like iron,


in the karlsruhe physics course one defines the term " substance - like " quantity : let my cite the definition from a paper by falk, herrmann and schmid : " there is a class of physical quantities whose characteristics are especially easy to visualize : those extensive physical quantities to which a density can be assigned. these include electric charge, mass, amount of substance ( number of particles ), and others. because of the fundamental role these quantities play throughout science and because such quantities can be distributed in and flow through space, we give them a designation of their own : substance - like. " are there examples of extensive quantities, which are not substance - like? i think volume is one example, since it seems to make no sense to assign a density to it, are there others? now the authors write that a quantity can only be conserved if it is substance - like, let my cite this from an other publication : f. herrmann, writes : " it is important to make clear that the question of conservation or non - conservation only makes sense with substance - like quantities. only in the context of substance - like quantities does it make sense to ask the question of whether they are conserved or not. the question makes no sense in the case of non - substance - like quantities such as field strength or temperature. " so my second question is : why has a conserved quantity to be substance like? it would be great if one could give me a detailed explanation ( or a counterexample if he thinks the statement is wrong ). are there resources where the ideas cited above are introduced with some higher degree of detail and rigour?


and q ) is equiv. to ( q and p ) | | association ( 1 ) | | [ p ∨ ( q ∨ r ) ] [ ( p ∨ q ) ∨ r ] | | p or ( q or r ) is equiv. to ( p or q ) or r | | association ( 2 ) | | [ p ∧ ( q ∧ r ) ] [ ( p ∧ q ) ∧ r ] | | p and ( q and r ) is equiv. to ( p and q ) and r | | distribution ( 1 ) | | [ p ∧ ( q ∨ r ) ] [ ( p ∧ q ) ∨ ( p ∧ r ) ] | | p and ( q or r ) is equiv. to ( p and q ) or ( p and r ) | | distribution ( 2 ) | | [ p ∨ ( q ∧ r ) ] [ ( p ∨ q ) ∧ ( p ∨ r ) ] | | p or ( q and r ) is equiv. to ( p or q ) and ( p or r ) | | double negation | | p ¬¬p | | p is equivalent to the negation of not p | | transposition | | ( p → q ) ( ¬q → ¬p ) | | if p then q is equiv. to if not q then not p | | material implication | | ( p → q ) ( ¬p ∨ q ) | | if p then q is equiv. to either not p or q | | material equivalence ( 1 ) | | ( p ↔ q ) [ ( p → q ) ∧ ( q → p ) ] | | ( p is equiv. to q ) means, ( if p is true then q is true ) and ( if q is true then p is true ) | | material equivalence ( 2 ) | | ( p ↔ q ) [ ( p ∧ q ) ∨ ( ¬q ∧ ¬p ) ] | | ( p is equiv. to q ) means, either ( p and q are true ) or ( both p and q are false ) | | exportation | | [ ( p ∧ q ) → r ] [ p → ( q → r ) ] | | from ( if p and q are true then r is true ) we can prove ( if q is true then r is true, if p is true ) | | importation | | [ p


what is an ssl certificate? the secure sockets layer ( ssl ) protects data transferred over http using encryption enabled by a servers ssl certificate. an ssl certificate is an electronic file that uniquely identifies individuals and web sites and enables encrypted communications. an ssl certificate contains a public key and a private key. a public key is used to encrypt information and a private key is used to decipher it. when a browser points to a secured domain, an ssl handshake authenticates the server and the client and establishes an encryption method and a unique session key. they can begin a secure session that guarantees message privacy and message integrity. ssl certificates serve as a kind of digital passport or credential. typically, the " signer " of a certificate is a " certificate authority " ( ca ), such as verisign. encryption, the process of transforming information to make it unintelligible to all but the intended recipient, forms the basis of data integrity and privacy necessary for e - commerce. customers submit sensitive information and purchase goods or services via the web only when they are confident that their personal information is secure. the solution for businesses that are serious about online transactions is to implement a trust infrastructure based on encryption technology. the diagram below illustrates the process that guarantees protected communications between a web server and a client. all exchanges of ssl certificates occur within seconds, and require no action by the consumer.


of solar gases at temperatures as high as 5 million degrees k ( 9 million deg. f ). while the sun is more than 99. 9 percent hydrogen and helium, it carries significant quantities of carbon, iron, calcium, silicon, and other elements. heavier elements have more protons ( carbon is 6, iron is 26 ) in their nuclei than do lighter elements ( hydrogen is 1, helium is 2 ). that means that as electrons are stripped from heavier atoms, the charge of the larger number of protons is devoted to the few remaining electrons. it takes ever more energy to strip off another electron. as a result, light from energetic atoms acts like a tracer that reveals where the sun is hot and at what temperatures. this is important to dissecting activities from the sun ' s corona - its outer atmosphere - through the transition region and to the chromosphere and photosphere - the visible " surface. " the challenge is that the x - ray emissions are so energetic that they pass through materials rather than being reflected as visible light would be. the usual trick to making x - ray images is called grazing incidence reflection. just as light will reflect off clear glass ( or a rock will skip on a pond ) if it strikes at a shallow angle, x - rays will reflect - and be focused - if they, too, strike at an even shallower angle. several x - ray telescopes, such as, the advanced x - ray astrophysics facility use this. the mssta works by a different effect. its multi - layer mirrors comprise an ultrasmooth mirror coated by up to 100 layers of heavy elements like tungsten spaced by layers of lightweight elements like carbon. in effect, the layers work like a bragg crystal, which will reflect x - rays. everything is extremely smooth, on the order of 0. 1 nm ( a 10 billionth of a meter, or 1 / 250 millionth of an inch ). these reflect a little bit of the x - rays at the surface of each layer pair. the choice of materials and the thickness of the layers determine precisely which wavelength is making the x - rays interfere with each other reflection. in this way, the scientists can fine tune a telescope to observe in a narrow band of wavelengths ( a spectral band ) or even one wavelength. that makes it possible to measure the temperature of the solar atmosphere. to observe the sun in several wavelengths at once, several telescopes must be flown together. this unique approach makes it possible to use conventional optical layouts - like the hubble space


winner : quantum leap quantum - dot lasers from japan ' s qd laser will make high - speed " fiber to the home " networks simpler, cheaper, and more power - efficient image : qd laser collecting the dots one of qd laser ’ s achievements, as shown in these atomic - force microscope images, was to double the dot density in its quantum - dot lasers, from 30 billion [ left ] to 60 billion [ right ] dots per square centimeter. this is part of ieee spectrum ' s special report : winners & losers 2009, the year ' s best and worst of technology. japanese start - up qd laser ’ s yasuhiko arakawa [ left ] and mitsuru sugawara oversaw the 15 - year effort to commercialize a temperature - stable semiconductor laser. suppose you had a dog whose personality fluctuated with the weather. on cool, crisp mornings, he ’ s a champ, fetching, rolling over, and shaking hands at your slightest command. but as the sun climbs higher and the day warms up, he becomes less and less responsive, and you have to ply him with doggy treats to get him to obey. and during heat waves? forget about it — he barely plays dead unless you double or triple his kibble ration. while you could excuse such behavior in fido, something remarkably similar goes on all the time with the semiconductor lasers used in cd and dvd players and in optical communications. these tiny devices are incredibly sensitive to heat. even a small rise in temperature causes the electrons within to move around faster and migrate out of the laser ’ s active layer — the thin slice of semiconducting material where the electrons recombine with positively charged holes to make light. as a result, the laser ’ s light output fluctuates, and it needs stronger and stronger electrical currents to keep lasing. at 85 °c, the device might need two or three times as much current to produce the same amount of light as at 25 °c. to get around that shortcoming, developers of semiconductor lasers must either cool them or introduce extra circuitry that maintains the device ’ s output even as the temperature fluctuates. but those workarounds increase both the cost of making the lasers and the power they consume. ever since this problem came to light, researchers have been hunting for a semiconductor laser that is inherently stable. one promising technology, first proposed 27 years ago, is the quantum - dot laser. such a device tightly confines the electrons and holes within many nanoscale


this problem came to light, researchers have been hunting for a semiconductor laser that is inherently stable. one promising technology, first proposed 27 years ago, is the quantum - dot laser. such a device tightly confines the electrons and holes within many nanoscale blobs, or dots, of semiconducting material. with enough dots — millions or billions, that is — lasing will occur and steady output maintained, regardless of external temperature. while researchers can now grow these devices using standard molecular - beam epitaxy equipment, mass - producing them has been very tricky. the japanese start - up qd laser, of tokyo, a joint venture of fujitsu and mitsui venture capital corp., has finally succeeded. its quantum - dot lasers use inexpensive substrates made from gallium arsenide ( gaas ) and boast an industry - leading density of 60 billion dots per square centimeter [ see images, ” collecting the dots ” ]. compared with the conventional indium - phosphide lasers now used in optical networks, qd laser ’ s devices will consume just half the power while transmitting up to 10 gigabits of data per second at a wavelength of 1. 3 micrometers. best of all, they will generate the same output at any temperature from – 40 to 100 °c. to mass - produce the gaas laser chips, qd laser has partnered with one of japan ’ s leading consumer - electronics firms, which will use the same production lines on which it currently cranks out conventional red lasers for dvd and cd players, video - game consoles, and other products. ( qd laser says it will reveal the name of its partner later this year. ) the initial shipments of laser chips are destined for an unnamed optical equipment vendor, which sometime this spring will begin offering the world ’ s first optical transceivers incorporating a quantum - dot laser. fujitsu will almost certainly buy the transceivers for use in optical lans and fiber - to - the - home networks. the quantum - dot laser has long been envisioned as a successor to the quantum - well laser, itself an improvement on earlier laser designs because it confined the injected electrons to an extremely thin layer — no more than tens of nanometers thick — of active material. that way, it required less current to induce lasing. but like the ” bulk ” semiconductor lasers it superseded, the quantum - well laser is sensitive to temperature. in the active layer of a bulk semiconductor laser, which you can picture as a fat, rectangular


, it required less current to induce lasing. but like the ” bulk ” semiconductor lasers it superseded, the quantum - well laser is sensitive to temperature. in the active layer of a bulk semiconductor laser, which you can picture as a fat, rectangular slab, the electrons and holes move in three dimensions, and that makes their interactions hard to control. in a quantum - well laser, they can move in only two dimensions, but electrostatic fields tend to build up, pulling the electrons away from the holes. in both cases, an increase in temperature makes the electrons more unruly. researchers began looking at ways to confine the electrons even further. in 1980, yasuhiko arakawa, a 28a ¿ ¿ year - old associate professor at the university of tokyo, had an epiphany. ” i thought, if we fix the position of each electron by confining it in a small box, the energy distribution will not be affected by temperature, ” arakawa recalled in a recent interview at his office at the university of tokyo. each ” box ” would be a semiconducting nanosize crystal into which electrons and holes would be injected. the box would effectively prevent the electrons and holes from being thermally excited to higher energy states. he presented his quantum - box laser idea at the annual meeting of the japanese society of applied physics in march 1981. then, collaborating with another professor, hiroyuki sakaki, he published a paper on the topic in the 1 june 1982 issue of applied physics letters. the two researchers followed up with a series of experiments in which they confined electrons using 30 - tesla magnets and demonstrated that the devices worked the same over a wide temperature range. ” but i thought it would be impossible to fabricate such nanostructures until the 21st century, ” arakawa says. the quantum - box laser concept didn ’ t exactly set the world on fire. some people found it interesting but not particularly useful, while others concluded that the boxes would be structurally unstable. his early work ” attracted almost no one to the field, ” says arakawa, now an ieee fellow. today, he adds, thousands of researchers worldwide are working to advance the field. just three years after arakawa and sakaki ’ s paper, a research group at france ’ s centre national d ’ etudes des telecommunications ( cnet ) noticed a strange phenomenon in the ” superlattices ” they were trying to build out of extremely thin alternating layers of indium arsenide and gallium ars


research group at france ’ s centre national d ’ etudes des telecommunications ( cnet ) noticed a strange phenomenon in the ” superlattices ” they were trying to build out of extremely thin alternating layers of indium arsenide and gallium arsenide. studying their handiwork under an electron microscope, they noticed that some of the indium arsenide had formed tiny regular blobs atop the underlying layer of gallium arsenide. each blob, it turned out, was a quantum dot. the french team didn ’ t actually produce lasing from their weird structure, but it was a start. in 1994, a team at the tokyo institute of technology and a collaboration of the technical university of berlin, russia ’ s ioffe physico - technical institute, and the max planck institute of microstructure physics independently demonstrated the first quantum - dot lasers. ( at that point, the quantum - dot versus quantum - box terminology was still in flux, with the german - russian team using the former term and the japanese using the latter. eventually, arakawa says, the world settled on quantum dot. ” now even i call them quantum dots, ” he says. ) but it ’ s one thing to create an experimental device in the lab and another thing to mass - produce a laser that operates reliably, can be manufactured cheaply, and performs a useful function. qd laser ’ s president and ceo, mitsuru sugawara, and his colleagues began chipping away at the problem of commercialization in 1994. sugawara was then a research physicist at fujitsu, aiming to develop a temperature - stable laser that emitted at 1. 3 µm, the best wavelength for optical communications. ” we weren ’ t interested in quantum dots per se, ” sugawara recalled in an interview last fall. like the cnet group, he and his team had been working on superlattices when they noticed quantum dots forming spontaneously, sugawara says, ” like water beading up on a waxed car. ” after realizing what they ’ d done, they set to work on building a laser. ” we knew that to produce lasing, we had to increase the density of the dots, so we started to study how to grow them intentionally, ” he says. five years later, in 1999, they demonstrated their first quantum - dot laser with a wavelength of 1. 3 µm. in a perfect world, the fujitsu group would have continued to make steady progress,


arakawa ’ s labs at the university of tokyo. there are currently 30 scientists and engineers involved, including five at the university of tokyo. after its founding, the starta ¿ ¿ up continued to work on boosting the lasers ’ dot density. ” we thought we could keep adding more layers, but we realized that wasn ’ t enough, ” sugawara says. using proprietary techniques, researchers at qd laser and tokyo university eventually succeeded in doubling the dot density, from 30 billion dots per square centimeter to 60 billion. sugawara brings out two atomic - force microscope images of quantum dots. the first shows a sparsely dotted surface. ” everyone can make this density, ” he says. then, pointing to the second image, which is crowded with dots, he says, ” but only we can make this. ” qd laser isn ’ t the first company to bring a quantum - dot laser to market. that distinction belongs to innolume, a start - up based in dortmund, germany, and santa clara, calif. since 2007 it has sold quantum - dot ” comb ” lasers, which can emit tens to hundreds of colors over a range of wavelengths. the devices are potentially suitable for optical computing, laser television, and biomedical applications. but innolume has yet to find a wide market for its products. qd laser will do better because its corporate backers have the muscle to see that it does. fujitsu has already agreed to replace the standard indium - phosphide lasers in its optical networking systems with qd laser ’ s gallium - arsenide lasers. but even fujitsu had to be convinced that the new devices would be as reliable as existing lasers. ” the communications market is very conservative, ” sugawara notes. to make its products more palatable to optical equipment makers like fujitsu, his company spent months tailoring the quantum - dot laser ’ s output power and performance so that they matched those of a conventional laser. the resulting laser can seamlessly replace an indium - phosphide laser in an optical transceiver, with no significant redesign required. with telecom giant nippon telegraph and telephone corp. adding 3 million fiber - to - the - home connections each year, sugawara thinks his company could claim 5 to 10 percent of the japanese market by 2011. qd laser is also working on lasers for long - distance communications of up to 20 kilometers. at press time, the company was wrapping up reliability tests and planned to begin selling in the spring.


green light, you similarly start with a 1064 - nm laser and double the frequency to get a 532 - nm wavelength. quantum - dot lasers could also be used in laser tv sets, medical devices, and tiny portable projectors that fit in your cellphone. in the next couple of decades, arakawa says, we ’ ll see quantum dots showing up in quantum computers and other it devices [ for more on quantum computing, see ” dot to dot design, ” ieee spectrum, september 2007 ]. but why stop there? quantum - dot researchers have been looking at ways to use quantum dots in biochemical sensors, solar cells, and other technologies. it ’ s a future arakawa modestly refers to as ” quantum dots for everything. ” for more articles, go to winners & losers 2009 special report. snapshot : a laser that ’ s right on the dot goal : to commercialize a reliable and inexpensive semiconductor laser that ’ s also immune to temperature changes. why it ’ s a winner : these high - speed, low - power, temperature - stable lasers are equally applicable to optical networking and consumer electronics. who : qd laser, a joint venture of fujitsu and mitsui venture capital corp., and university of tokyo where : tokyo and atsugi, japan staff : 30 scientists and engineers budget : us $ 14 million when : spring 2009


key : " s : " = show synset ( semantic ) relations, " w : " = show word ( lexical ) relations display options for sense : ( gloss ) " an example sentence " - s : ( n ) burning, combustion ( the act of burning something ) " the burning of leaves was prohibited by a town ordinance " - s : ( n ) burn, burning ( pain that feels hot as if it were on fire ) - s : ( n ) combustion, burning ( a process in which a substance reacts with oxygen to give heat and light ) - s : ( n ) electrocution, burning ( execution by electricity ) - s : ( n ) burning, burning at the stake ( execution by fire ) - s : ( n ) burning ( a form of torture in which cigarettes or cigars or other hot implements are used to burn the victim ' s skin ) - s : ( v ) burn, fire, burn down ( destroy by fire ) " they burned the house and his diaries " - s : ( v ) burn, glow ( shine intensely, as if with heat ) " the coals were glowing in the dark " ; " the candles were burning " - s : ( v ) burn, combust ( undergo combustion ) " maple wood burns well " - s : ( v ) bite, sting, burn ( cause a sharp or stinging pain or discomfort ) " the sun burned his face " - s : ( v ) burn, combust ( cause to burn or combust ) " the sun burned off the fog " ; " we combust coal and other fossil fuels " - s : ( v ) burn ( feel strong emotion, especially anger or passion ) " she was burning with anger " ; " he was burning to try out his new skies " - s : ( v ) burn, incinerate ( cause to undergo combustion ) " burn garbage " ; " the car burns only diesel oil " - s : ( v ) burn ( execute by tying to a stake and setting alight ) " witches were burned in salem " - s : ( v ) burn ( spend ( significant amounts of money ) ) " he has money to burn " - s : ( v ) burn ( feel hot or painful ) " my eyes are burning " - s : ( v ) cauterize, cauterise, burn ( burn, sear, or freeze ( tissue ) using a hot iron or electric current or a caustic agent ) " the surgeon cauterized the wart " - s :


it can be tuned for specific applications. the cation distribution in the ferrite nanoparticles was investigated using x ray absorption ( xa ) and x - ray magnetic circular dichroism ( xmcd ) at the fe l2, 3 and co l2, 3 edges, measured at als beamline 4. 0. 2. an xmcd spectrum is obtained as the difference between two xa spectra measured in opposite external magnetic fields. magnetite has an inverse spinel crystal structure, which contains tetrahedral ( td ) and octahedral ( oh ) sites accommodating fe2 + and fe3 + cations. each specific cation in the spinel structure generates a unique xmcd signature determined by its valence state ( number of d electrons ), site symmetry ( i. e., td or oh ), and moment direction, which can be computed using atomic multiplet calculations. by fitting a weighted sum of these calculated spectra to the measured xmcd spectra, the site occupations of the fe cations can be obtained. the biogenic materials show a striking change with increasing co amount, namely a decrease in intensity of the leading negative peak in the fe l3 edge, which implies that co is predominantly replacing fe2 + cations in octahedral sites. similarly, the site occupancy and oxidation state of the co can be directly assessed by examining the co l2, 3 xa and xmcd spectra. the close similarity with the spectra for synthetically produced cofe2o4 thin films confirmed that the bacteria were able to suitably accommodate co in the ferrite structure with the co2 + residing primarily on oh sites. the xmcd measurements indicate a dramatic enhancement in the magnetic properties of biogenically produced nanoparticles when large quantities of co are introduced into the spinel structure, a major advance over previous biomineralization studies. inclusion of other transition metals into the spinel structure by fe ( iii ) - reducing bacteria to tailor the magnetic properties of nanoferrites could lead to a suite of materials required for different technological uses. the successful production of highly ordered crystalline nanoparticulate ferrites demonstrates the potential for scaled - up industrial manufacture of nanoparticles using environmentally benign and energy - efficient methodologies. research conducted by v. s. coker, n. d. telling, r. a. d. pattrick, c. i. pearce, j. r. lloyd, f. tuna


speaker drum or air particles. either way, the signal ends up looking like an erratic wavelike squiggle. but when you listen to the sound produced from that squiggle, you can clearly distinguish all the instruments in a symphony orchestra, playing discrete notes at the same time. that ' s because the erratic squiggle is, effectively, the sum of a number of much more regular squiggles, which represent different frequencies of sound. " frequency " just means the rate at which air molecules go back and forth, or a voltage fluctuates, and it can be represented as the rate at which a regular squiggle goes up and down. when you add two frequencies together, the resulting squiggle goes up where both the component frequencies go up, goes down where they both go down, and does something in between where they ' re going in different directions. the dft does mathematically what the human ear does physically : decompose a signal into its component frequencies. unlike the analog signal from, say, a record player, the digital signal from an mp3 player is just a series of numbers, representing very short samples of a real - world sound : cd - quality digital audio recording, for instance, collects 44, 100 samples a second. if you extract some number of consecutive values from a digital signal - - 8, or 128, or 1, 000 - - the dft represents them as the weighted sum of an equivalent number of frequencies. ( " weighted " just means that some of the frequencies count more than others toward the total. ) the application of the dft to wireless technologies is fairly straightforward : the ability to break a signal into its constituent frequencies lets cell - phone towers, for instance, disentangle transmissions from different users, allowing more of them to share the air. the application to data compression is less intuitive. but if you extract an 8x8 block of pixels from an image, each row or column is simply a sequence of eight numbers - - like a digital signal with eight samples. the whole block can thus be represented as the weighted sum of 64 frequencies. if there ' s little variation in color across the block, the weights of most of those frequencies will be zero or near zero. throwing out the frequencies with low weights allows the block to be represented with fewer bits but little loss of fidelity. demanet points out that the dft has plenty of other applications, in areas like spectroscopy, magnetic resonance imaging, and quantum computing. but ultimately, he says, " it ' s


" inexactness " or the " uncertainty " principle, as formulated by physicist werner heisenberg, is an end often seen as the beginning. it reflects t. s. eliot ' s observation : " what she gives, gives with such supple confusions that the giving famishes the craving ". in 1927, heisenberg showed that uncertainty is inherent in quantum mechanics. it is impossible to simultaneously measure certain properties — position and momentum. in the quantum world, matter can take the form of either particle or waves. fundamental elements are neither particles nor waves, but can behave as either and are merely different theoretical ways of picturing the quantum world. the profound beauty of inexactness transects science, mathematics, method, philosophy, linguistics and faith. inexactness marks an end to certainty. in seeking to measure one property more precisely and accurately, the ability to measure the other property is undermined. the act of measurement negates elements of our knowledge of the system. it undermines scientific determinism, implying that human knowledge about the world is always incomplete, uncertain and highly contingent. inexactness challenges causality. as heisenberg observed : " ' if we know the present, then we can predict the future ', it is not the consequences, but the premise that is false. as a matter of principle we cannot know all determining elements of the present ". inexactness questions methodology. experiments can only prove what they are designed to prove. inexactness is a theory based on the practical constraints of measurement. inexactness and quantum mechanics challenge faith as well as concepts of truth and order. they imply a probabilistic world of matter, where we cannot know anything with certainty but only as a possibility. it removes the newtonian elements of space and time from any underlying reality. in the quantum world, mechanics are understood as a probability without any causal explanation. albert einstein refused to accept that positions in space - time could never be completely known and quantum probabilities did not reflect any underlying causes. he did not reject the theory but the lack of reason for an event. writing to max born, he famously stated : " i, at any rate, am convinced that he [ god ] does not throw dice. " but as stephen hawking later remarked in terms that heisenberg would have recognised : " not only does god play dice, but … he sometimes throws them where they cannot be seen. " allusive and subtle, the power


throw dice. " but as stephen hawking later remarked in terms that heisenberg would have recognised : " not only does god play dice, but … he sometimes throws them where they cannot be seen. " allusive and subtle, the power of inexactness draws on its metaphorical property which has allowed it to penetrate diverse fields such as art theory, financial economics and even popular culture. at one level, heisenberg ' s uncertainty principle is taken to mean the act of measuring something changes what is observed. but at another level, intentional or unintentionally, werner heisenberg is saying something about the nature of the entire system — the absence of absolute truths, the lack of certainty and the limits to our knowledge. inexactness is linked with different philosophical constructs. nineteenth - century danish philosopher søren kierkegaard differentiated between objective truths and subjective truths. objective truths are filtered and altered by our subjective truths, recalling the interaction between observer and event central to heisenberg ' s theorem. inexactness is related to linguistic philosophies. in the tractatus logico - philosophicus, ludwig wittgenstein anticipates inexactness arguing that the structure of language provides the limits of thought and what can be said meaningfully. the deep ambiguity of inexactness manifests itself in other ways : the controversy over the term itself and heisenberg ' s personal history. heisenberg ' s principle is various referred to as ungenauigkeit ( meaning inexactness ), unscharfe ( blurred or lacking clarity ) or unbestimmtheit ( indeterminate ). in translation, the ambiguity and differences in meaning are accentuated. playwright michael franyn suggested : indeterminability. it was not until the publication of the 1930 english - language version of heisenberg ' s textbook, the physical principles of the quantum theory that the term uncertainty ( unsicherheit ) was used and widely adopted. in 1941, during the second world war, werner heisenberg and niels bohr, the danish physicist and his former teacher, met in occupied denmark. in michael franyn ' s 1998 play copenhagen, margrethe, bohr ' s wife, poses the essential question, which is debated in the play : " why did he [ heisenberg ] come to copenhagen? " the play repeats their meeting three times, each with different outcomes. as heisenberg, the character


the entire physical universe is made up of pure energy and vibration. when you have the insight to see everything as vibration, the nature of the universe is revealed to you. light is vibration. the entire electromagnetic wave spectrum of visible light produces different colors. colors are simply waves vibrating at different frequencies. on one end of the spectrum you have red, on the other end you have violet. red has the longest wavelength and the lowest frequency, violet has the shortest wavelength and the highest frequency. there are two kinds of electrical lighting that you can find when you visit an electronic store. warm light and cool light. warm light contains a greater mixture of lower frequency color waves such as yellow and orange. cool light contains a greater mixture of higher frequency color waves such as green and blue. light is crucial in its environmental effect upon work, play, rest and other life activities. it controls stimulation, relaxation and energy level. since warm light is more relaxing than cool light, you might decide to use it for the ambience it creates. have you ever used only warm lights in a room and thought that you could make the place more relaxing or stimulating simply by increasing or decreasing the light intensity? but it doesn ’ t work that way. increasing the light intensity of warm light does not make it a lot more stimulating. higher energy levels require higher rate of vibration. it is not the magnitude but the frequency of the vibration that determines it ’ s energy level. is it any wonder that blue flame is hotter than yellow flame? health is vibration. cold, damp and dark places with lack of airflow are breeding grounds for bacteria, whereas sunny places with abundance of airflow eliminate unhealthy micro organisms. the second type of environment is healthier than the first because it is high vibration while the other is low vibration. although sunlight is biologically beneficial, too much of it causes heatstroke. the energy turns from being constructive to destructive. the key here is balance. too much of something beyond the rightful amount causes instability. this is what all sickness and disease does. it seeks to weaken or destabilize vibration. the more vibrant and stable a person is, the more alive and constructive he / she are. the more lackluster and unstable he / she is, the less alive and / or the more ( self ) destructive. ever wonder why you have always been told to drink warm water and not to drink cold one when you were sick? when the body is sick, there are things within that are clogging up the system and slowing


bodies ” at every level, physical and non - physical, has a profound influence on our ability to attract positive experiences. the higher your vibration, the more of a “ magnet ” you become as a result of the thoughts you hold in your mind. by holding only thoughts of the “ things ” you wish to manifest into your experience, and keeping your vibrations high in the ways we discussed previously, you will find your wishes will manifest much more quickly. when you learn to see everything as vibration different in terms of rate and stability, you will understand what you need in order to obtain the desired effect in any situation. it is all about balancing vibrations. there are lots more aspects of physical reality than those mentioned here where this principle is applied to. once you are aware of this principle and always think in terms of vibration, you can understand practically everything that happens in the physical world. this is one of the governing dynamics that allows you to make sense of everything. having this awareness is like seeing the world in code, like the matrix. - persistence of will manifests what you desire - affecting probable outcomes with your mind - casting magic spells and intention manifestation - shared reality - cooperative mental creation - actively defend your beliefs against conflict - mentally uniting with your desire by giving thanks for it - speaking your intention gives it more power - letting extremes guide you to balance of mind - purchasing the best things in life for yourself - everything is formed by vibration and geometry


an instrument to measure the altitude of an object above a fixed level. generally, mean sea level is used for the reference level. mid - level cloud ( bases generally 2000 - 8000m ), made up of grey, puffy masses, sometimes appearing in parallel waves or bands. an indicatorof mid - level instability. altocumulus can take on various forms such as aclenticularis, ac undulatus, ac castellanus, altocumulus ' mackerel sky '. a middle level cloud with vertical development that forms from altocumulusclouds. it is composed primarily of ice crystals in its higher portions andcharacterised by its turrets, protuberances or crenulated tops. mid - level cloud composed of water droplets and ice crystals. usuallygives the sun a watery or dimly visible appearance. a local wind that flows up the side of valleys due to increased heating alongthe valley walls. often the anabatic wind results in cumulus clouds along theridges either side of the valley. see also katabatic winds. a device used to measure wind speed. the departure of an element from its long - term average for the locationconcerned. for example, if the average maximum temperature for melbourne in june is 14 degrees and on one particular day the temperature only reaches 10 degrees, than the anomaly for that day is - 4. a large scale atmospheric circulation system in which the winds rotate anticlockwise in the southern hemisphere ( clockwise in northern hemisphere ). anticyclones are areas of high atmospheric pressure and are generallyassociated with light winds and stable weather conditions. interchangeablewith high pressure system. rotation in the opposite sense as the earth ' s rotation, i. e., anticlockwise in


ulbrich : glossary abrasion : a roughening or scratching of a surface due to abrasive wear. on aluminum parts, also known as a rub mark or traffic mark. abrasion - resistant steels ( ar ) : a family of steel products developed for those applications involved in sliding and / or impact abrasion. abrasive wear : the removal of material from a surface when hard particles slide or roll across the surface under pressure. the particles may be loose or may be part of another surface in contact with the surface being worn. contrast with adhesive wear. accelerated corrosion test : a test conducted under controlled conditions that are considerably more severe than those natural conditions whose effects are presumably being investigated. the advantages of such a test is the relatively short time required. results are useful for qualitative comparisons, but are not reliable for predicting anticipated life in actual service. accordion reed steel : hardened, tempered, polished and blued or yellow flat steel with dressed edges. carbon content about 1. 00 %. material has to possess good flatness, uniform hardness and high elasticity. acid steel : steel melted in a furnace with an acid bottom and lining and under a slag containing an excess of an acid substance such as silica. acid - brittleness : brittleness resulting from pickling steel in acid ; hydrogen, formed by the interaction between iron and acid, is partially absorbed by the metal, causing acid brittleness. age - hardening : a process of aging that increases hardness and strength and usually decreases ductility. ( see precipitation heat treatment ) air - hardening steel : a steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. such steels attain their martensitic structure without going through the quenching process. additions of chromium, nickel, molybdenum and manganese are effective toward this end. the term should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 in. or more in diameter. aircraft quality : denotes material for important or highly stressed parts of aircraft for other similar purposes ; such materials are extremely high quality requiring closely controlled, restrictive and special practices in their manufacture. aging : a process generally accelerated by temperature, wherein changes in mechanical properties occur in certain metals. these changes generally raise room temperature hardness, tensile and yield strength, while lowering ductility. aisi : american iron and steel institute. published steel