- to buck ; jump from the ground with the legs bunched together, as a mustang or mule. sportsman ' s gazetteer. see cut under buck. - n. the highest point or reach ; height ; acme. - n. height ( or depth ) in general ; point or degree of elevation ( or of depth ) ; degree ; point. - n. in acoustics and music : - n. that characteristie of a sound or a tone which depends upon the relative rapidity of the vibrations by which it is produced, a relatively acute or high pitch resulting from rapid vibrations, and a relatively grave or low pitch from slow vibrations. pitch is therefore coordinate with force, timbre, and duration. it is estimated and stated in terms of the vibration per second of the sounding body. it is experimentally determined either by direct comparison with a standard tuning - fork or by such instruments as the siren. - n. a particular tonal standard or example with which given tones may be compared in respect to their relative height : as, concert pitch ; french pitch. various standards have from time to time been used or promulgated — as, for example, classical pitch, during the last half of the eighteenth century, for the a next above middle c about 415 to 430 vibrations per second ; concert pitch ( commonly called high pitch ), used in concert and operatic music during the middle of the nineteenth century, varying for the same a from about 440 to 455 vibrations ; french pitch ( commonly called low pitch ), the diapason normal adopted by the french academy in 1859, for the same a 435 vibrations ; philosophical pitch, an arbitrary pitch for middle c, obtained by taking the nearest power of 2, that is, 256 vibrations, or for the next a above about 427 vibrations ; scheibler ' s pitch, adopted by the stuttgart congress of physicists in 1834, for the same a 440 vibrations. - n. specifically. - n. the height to which a hawk rises in the air when waiting for game to be flushed, or before stooping on its prey. - n. stature ; height. - n. inclination ; angle to the horizon. - n. in mech. : - n. the distance between the centers of two adjacent teeth in a cog - wheel, measured on the pitch - line, which is concentric with the axis of revolution, and at such a distance from the base of the teeth as to have an equal rate of motion with a similar line in the cog -


a throw ; a toss ; a cast, as of something from the hand. - n. ( cricket ) that point of the ground on which the ball pitches or lights when bowled. - n. a point or peak ; the extreme point or degree of elevation or depression ; hence, a limit or bound. - n. obsolete height ; stature. - n. a descent ; a fall ; a thrusting down. - n. the point where a declivity begins ; hence, the declivity itself ; a descending slope ; the degree or rate of descent or slope ; slant. - n. ( mus. ) the relative acuteness or gravity of a tone, determined by the number of vibrations which produce it ; the place of any tone upon a scale of high and low. - n. ( mining ) the limit of ground set to a miner who receives a share of the ore taken out. - n. the distance from center to center of any two adjacent teeth of gearing, measured on the pitch line ; - - called also circular pitch. - n. the length, measured along the axis, of a complete turn of the thread of a screw, or of the helical lines of the blades of a screw propeller. - n. the distance between the centers of holes, as of rivet holes in boiler plates. - n. ( elec. ) the distance between symmetrically arranged or corresponding parts of an armature, measured along a line, called the pitch line, drawn around its length. sometimes half of this distance is called the pitch. - v. heel over - v. move abruptly - n. abrupt up - and - down motion ( as caused by a ship or other conveyance ) - v. throw or toss with a light motion - v. set the level or character of - v. sell or offer for sale from place to place - n. a high approach shot in golf - n. the property of sound that varies with variation in the frequency of vibration - v. set to a certain pitch - n. any of various dark heavy viscid substances obtained as a residue - v. fall or plunge forward - n. degree of deviation from a horizontal plane - v. lead ( a card ) and establish the trump suit - n. ( baseball ) the act of throwing a baseball by a pitcher to a batter - v. hit ( a golf ball ) in a high arc with a backspin - n. the action or manner of throwing something - v. throw or hurl


theory of elasticity the theory of elasticity means, when the property of solid materials to deform under the application of an external force and getting back to their original shape after the external force is removed. the external force which is applied on the external force is said to be stress, the amount of deformation is called the strain. when the material has a force applied to it, let say, the compressive force is acting at each end of a bar ; there will be an internal reaction to that force. this leads to the newton ’ s third law, for every action there is an equal and opposite reaction. the internal reaction of the bar has the magnitude which is equal to the applied force. this will be very useful for engineers for considering the reactive force which is equally distributed over the cross sectional area of the bar. when the material has applied force on it, that material will be deformed neither plastically ( permanently ) nor elastically. in elastic structures such as buildings and bridges, if the force is removed the change in shape will disappear. strain is nothing but, the degree of deformation extension, compression, shear or torsion as a proportion of the original size of a material. strain is a proportion, or ratio, so it is dimensionless, i. e. it does not have units. depending on the amount of deformation, the strain can be expressed in percentage. the use of stress and strain in place of load and deformation will make the calculation easier for engineers. the linearized theory of elasticity the linearized theory of elasticity has played the vital role in the analysis of engineering. the engineers have used the linearized theory of elasticity from the cast iron and steel truss bridges of the eighteenth century till the international space station. they are using them in making design decisions effecting the strength, stiffness, weight, and cost of structures and components. the linearized theory of elasticity includes a comprehensive introduction to tenor analysis, specification of boundary conditions, and a survey of solution methods for important class of problems. it covers two and three dimensional problems, torsion of noncircular cylinders, variational methods and complex variable method. an widespread treatment of important solutions and solution methods, including the use of potentials, variational methods, and complex variable methods, follows the development of the linearized theory.


lets say i want to build a simple chat program that has encryption that is impossible to crack for anyone, even a theoretical government with a massive super computer. ok here ' s my idea. you ' ll need to read all the points to get the whole picture i think. - only two people can communicate with each other with the chat program. no group conversations. - the people will be communicating over the internet. - the chat program will just handle basic characters, numbers and symbols that are on a standard us keyboard. this is to keep things simple. - we ' ll say there ' s a limit of 160 characters per single chat message. but obviously being a real - time chat program over the internet you can type up more than one message. chat person # 1 ( bob ) generates a large list of secret random keys ( or pads ). each one time pad is 160 characters long. so we end up with a long list of pads. these get put in a sqlite database or something with primary keys numbered from say 1 to 5000. - bob copies the database to a usb drive / cd / dvd / blu - ray and meets chat person # 2 ( alice ) in person and gives them the database. alice loads that database up on her computer. then they secure erase the usb drive or burn / smash the cd / dvd / blu - ray. anyway now they both have the same list of one time pads on their computers. - ok bob, seeing he generated the list, he uses the odd numbered primary key pads to encrypt and send messages to alice ( # 1, # 3, # 5 etc ). alice being the person who loaded the list, uses the even numbered primary key pads ( # 2, # 4, # 6 etc ) to encrypt and send messages back to bob. - each person ' s program always keep a record of which numbered pad they ' ve used, so that a message doesn ' t get encrypted twice with the same pad. there ' s no mixup in one person using the same pad as the other because they ' re using odd and even numbered pads. the number of the pad to be used for decrypting the message could be tacked onto the end of the message. the number of the pad to be decrypted wouldn ' t necessarily need to be encrypted either it could just be on the end of the message eg " # 123 ". - now to secure the session, and provide a layer of protection against


pad to be decrypted wouldn ' t necessarily need to be encrypted either it could just be on the end of the message eg " # 123 ". - now to secure the session, and provide a layer of protection against mitm attacks, the whole chat session could be encrypted with ssh or ssl maybe. - now suppose the chat session gets intercepted by an attacker ( eve ) who wants to interfere with the communications, maybe trick bob into sending another message again with the same pad so they can figure out what was said. well she won ' t be able to because bob is maintaining a list of all the pads he ' s used and all the numbered pads that alice has sent him. if attacker eve tries to send a different message to bob to pretend it ' s from alice then she can ' t because she doesn ' t have any pads to encrypt the message with. - if eve tampers with the number on the end specifying the pad to decrypt with then the receiver will try and decrypt that message and realise the message is garbled so they will know something is up. if she tried to re - use an old pad then bob would know too as that message has already been received indicating tampering. also if the number increased significantly from the last message received eg last message received was # 200 and the next one received was # 230 then you ' d know there ' s been missing messages or someone playing man in the middle. - when the two parties have used up their 5000 messages then the chat session is ended and they ' ll need to regenerate a list of pads again and give them to the other chat party in person so they can continue chatting. obviously 5000 pads is an arbitrary number. you could in theory generate a million pads and have communication with them for a life time. ok so that ' s my idea in a nutshell, i ' ve had it on my mind for a while. if it ' s workable this would be an open source app that i would develop myself and release for everyone to use. open source because the code can be scrutinised and tested for flaws by the experts. are there any potential flaws or weaknesses, or possible attack vectors you can see? what improvements would you make to the idea?


etd at indian institute of science > division of earth and environmental sciences > civil engineering ( civil ) > please use this identifier to cite or link to this item : | title : | | stabilised rammed earth for walls : materials, compressive strength and elastic properties | | authors : | | kumar, prasanna p | | advisors : | | reddy, b v venkatarama | | keywords : | | structural analysis ( civil engineering ) | cement stabilised rammed earth rammed earth buildings cement stabilised rammed earth walls rammed earth - strength rammed earth - elastic properties soil - stability stabilised rammed earth | submitted date : | | jul - 2009 | | series / report no. : | | g23519 | | abstract : | | rammed earth is a technique of forming in - situ structural wall elements using rigid formwork. advantages of rammed earth walls include flexibility in plan form, scope for adjusting strength and wall thickness, variety of textural finishes, lower embodied carbon and energy, etc. there is a growing interest in the construction of rammed earth buildings in the recent past. well focused comprehensive studies in understanding the structural performance of rammed earth structures are scanty. clear - cut guidelines on selecting soil grading and soil characteristics, assessing strength of rammed earth walls, density strength relationships, limits on shrinkage, standardised testing procedures, behaviour of rammed earth walls under in - plane and out of plane loads, etc are the areas needing attention. the thesis attempts to address some of these aspects of cement stabilized rammed earth for structural walls. brief history and developments in rammed earth construction with illustrations of rammed earth buildings are presented. a review of the literature on rammed earth has been provided under two categories : ( a ) unstabilised or pure rammed earth and ( b ) stabilised rammed earth. review of the existing codes of practice on rammed earth has also been included. summary of the literature on rammed earth along with points requiring attention for further r & d are discussed. objectives and scope of the thesis are listed. the thesis deals with an extensive experimentation on cement stabilised rammed earth ( csre ) specimens and walls. four varieties of specimens ( cylindrical, prisms, wallettes and full scale walls ) were used in the experiments. a natural soil and its reconstituted variants were used in the experimental work. details of the experimental programme, characteristics of raw materials used in the experimental investigations, methods of preparing different types of specimens and their testing procedures are discussed in detail. influence of soil grading, cement content, moulding water


school : down to earth school area of science : engineering interim : we are concerned about children in our area getting burned by slides at local parks and in yards at home. children all over the u. s have been burned by playground equipment from the ages of 6 months to 6 years. most of the burns occur due to young children not having the reaction of pulling away from heated materials quick enough. density is defined as weight per unit volume, though more properly called “ specific weight ”. less dense materials heat faster because the amount of atoms is less and they take less time for all to heat. light from the sun excites electrons in the atoms which create the materials themselves. this is knows as “ radiationless transitions ”. the atoms of the material vibrate and that vibrational energy is roughly equal to the electronic energy ( photons ) absorbed from the sun. we hope to find a safer alternative material for slides by learning how the density of material holds heat and changes temperature. we hope to use this information to design a safer slide. the model programming we are using is netlogo. we will be modeling a slide being heated by rays from the sun. we plan to have the sun move across the sky, and agent - based heat rays that will travel to heat the slide. the slide will be made of color changeable patches. when the patches are hit by the rays they will change color. the starting patch color will depend on the density of the material in use and the temperature surrounding the area. the slide will begin flashing the warm colors when the temperature gets to skin burning degrees. we have the main part of our research completed to start our model. we have started on all our other projects involved in the challenge. we have begun our model with the sun and heat rays. we are working on getting the sun path laid out so the sun will follow it. we are also working on getting the heat rays attached to the sun and heading set for the slide. we would like for the model to show the suns angle and how it affects the temperature of the material. the results we expect to get include finding out what material heats up the most based on the density. we hope to find a solution on what materials would be safest.. we will be using the information to create a “ safe slide ”. kristen hampton. wistv. com. 621, 12 wbtv. http : / / www. wistv. com / story / 1884371 / hot - playground - equipment - can - burn - children


finding affordable ways to make technology available to everyone is a common challenge. now, a researcher at nasa ' s goddard space flight center, greenbelt, md. has done that with the process that creates " nanotubes. " a nanotube is a tiny, hollow, long, thin and strong tube with an outside diameter of a nanometer that is formed from atoms such as carbon. nanotubes are really important in technology, because when they are made a certain way, a nanotube can conduct ( allow movement of ) electricity as well as copper does. when they are made a slightly different way, nanotubes are electrical semiconductors, which mean they can be switched between insulating from electricity to conducting electricity. semiconductors make it possible to miniaturize electronic components. nanotubes can be either semiconductors or conductors depending on how they are made. nanotubes are also stronger than steel, so long filaments can be used to create super - tough lightweight materials. to understand how strong a nanotube is, think of a hair holding up a barbell. although the carbon nanotubes were discovered 15 years ago, their use has been limited due to the complex, dangerous, and expensive methods for their production. however, goddard researchers drs. jeannette benavides and henning leidecker developed a simpler, safer, and much less costly process to make these carbon nanotubes. the key was that they figured out how to produce bundles of these nanotubes without using metal, which reduced the costs tremendously and made a better quality product. earlier this year, nasa goddard licensed its patented technique for manufacturing these high - quality " single - walled carbon nanotubes " to idaho space materials ( ism ) in boise, idaho. now the carbon nanotubes based on this creation process are being used by researchers and companies that are working on things that will impact almost every facet of life, such as new materials with ceramics and polymers. polymers are tiny molecules strung in long repeating chains, like dna in our bodies. polymers are also in proteins and starches in foods we eat, or in plastics, for example. " ism believes that carbon nanotubes will be a building block for a better world, making people ' s lives better through a wide range of uses, including medical advances, fuel cells, video displays, solar cells, and a host of other applications, " explained ism vice president roger smith. " i ' m very excited to see that this agreement is


prog. theor. phys. vol. 82 no. 3 ( 1989 ) pp. 555 - 562 source abundance of cosmic rays randall laboratory of physics, university of michigan, ann arbor research institute for fundamental physics, kyoto university, kyoto 606 ( received march 4, 1989 ) the source abundance of primary cosmic rays is computed and compared with the solar abundance. then a model, proposed by one of the authors, which is based on quantum effects on gravity, is discussed and shown to yeild a prediction for the source abundance. the prediction of the model is compared with the calculated source abundance. doi : 10. 1143 / ptp. 82. 555 - john r. letaw, r. silberberg and c. h. tsao, ap. j. suppl. series 56 ( 1984 ), 369. - y. tomozawa, " cosmic rays, quantum effects on gravity, and gravitational collapse ", lectures given at the second workshop on fundamental physics, university of puerto rico, humacao, ed. e. esteban ( 1986 ), p. 144. - m. s. longair, high energy astrophysics ( cambridge university press, 1981 ), p. 312. - r. silberberg and c. h. tsao, ap. j. suppl. series no. 220 ( i ) 25 ( 1973 ), 315 ; no. 220 ( ii ) 25 ( 1973 ), 335. r. silberberg, c. h. tsao and j. r. letaw, ap. j. suppl. series 58 ( 1985 ), 873. - a. g. w. camerons, " elemental and nuclidic abundances in the solar system ", essays in nuclear astrophysics, ed. c. a. barkes, d. d. clayton and d. n. schramm ( 1982 ). - w. r. binns, r. k. fickle, t. l. garrard, m. h. israel, j. klarmann, e. c. stone and c. j. waddington, ap. j. 247 ( 1981 ), l115. - m. casse and p. gorel, ap. j. 221 ( 1978 ), 703 ( for z ≤28 ). n. r. brewster, p. s. frier and c. j. waddington, ap. j.


neutrons! so the big bang model — simply by stating the universe obeys general relativity and is expanding today — makes some very big predictions. among them is the prediction that, based on the fact that it was very hot and dense in the past and has been expanding and cooling ever since, we should form the lightest elements in the universe out of protons and neutrons when the universe is only a few minutes old! this includes deuterium, helium - 3, helium - 4, and lithium, in very specific proportions to one another, dependent only on the number of photons in the universe. this also means that, when the universe finally cools enough to form neutral atoms, those photons left over from the big bang should still be there, omnidirectionally, in our universe today. the only difference between then and now is that, because the universe has been expanding and cooling, this radiation is not only no longer visible to our eyes, it isn ’ t even infrared anymore! it ought to have redshifted all the way into the microwave portion of the spectrum. and what ’ s more than that, it ought to have a very particular spectral distribution, known as a blackbody spectrum. well, this microwave - wavelength radiation was discovered back in the 1960s everywhere in the sky, and its wavelength was determined to an incredible precision to be blackbody in the 1990s by the cobe satellite. and finally, it was only last year that the first absolutely pristine galaxies — made out of atoms that had never formed stars before — were found in the universe. but this gas was indeed verified to have the right elemental abundances of hydrogen and helium, with no trace of any heavy elements that shouldn ’ t be there! and with those three cornerstones in place — the expanding universe from the recession of distant galaxies, the abundances of the light elements, and the cosmic background of microwave radiation — the big bang has been verified in a way that no alternative has. none of the other options proposed can give us these three things together : not the tired light model, not the steady - state model, not a plasma cosmology, nothing. the big bang is the only model ever proposed that is consistent with these three pieces of data. of course, the big bang also gives us structure formation that matches galaxies and clusters in the universe. furthermore, it can actually be consistent with dark matter, dark energy and inflation, and every astronomical observation ever made and physical experiment ever performed. it ’ s not only the best theory


of marklund convection as misconstrued in the abovementioned sky & telescope article as being " falling inward ". the plasma flow is usually inwards as matter is accumulated in the filaments revealing helically twisted densities greater than the surrounding when coupled with the work of anthony peratt wherein : plasmas in relative motion are coupled by the currents they drive in each other and nonequilibrium plasma often consists of current - conducting in the laboratory and in the solar system, filamentary and cellular morphology is a well - known property of plasma. as the properties of the plasma state of matter is believed not to change beyond the range of our space probes, plasma at astrophysical dimensions must also be filamentary. - a. l. peratt and the universe : large scale dynamics, filamentation, and consider the structural formations : the plasma torus ( circumnuclear disk ), the " mini - spiral " enclosed within it, dust undergoing inwardly directed radial convection apparently up and out along the massive birkeland current filament away from the galaxy center. the very existence of such structural integrity stares in complete defiance of said black hole theory. during particle - in - cell simulations with up to 12 filaments peratt also noted that multiple birkeland currents can " neck off " leaving fewer ( 2 - 3 ) in number to account for the majority of " cosmic plasma phenomena ". through the decades long work of plasma physics the electric universe is not found " lacking a sturdy interpretive framework ". the double helix nebula fully demonstrates the nature of galactic - dimensioned birkeland currents. the double helix nebula : a magnetic torsional wave propagating out of the galactic centre : mark morris ( ucla ), keven uchida ( cornell ), tuan do ( ucla ) ( see pages 11 & 14 for graphical presentation of a trip to galactic center : sky & telescope the origin of the high - energy activity at the galactic center : f. yusef - zadeh, w. purcell, e. gotthelf permalink to this article. public comment may be made on this article on the thunderbolts forum / thunderblogs ( free membership required ).


phase diagram of esa complexes at 100 mm nacl salt concentration as a function of pentanol and dodecane content relative to the surfactant weight [ wt % ]. the natural phenomenon of self - assembly — how molecules or other entities gather to become ordered objects or arrays — occurs in many areas of science, from nanomaterials to biology. resulting from basic, well understood forces, such as electrostatics, self - assembly may allow scientists to manipulate materials at at tiny scales, ultimately yielding great advances in fields such as data storage, pharmaceuticals, and catalysis. in efforts to better understand self - assembly, many researchers are studying self - assembling systems in solution that consist of an electrolyte ( any molecule that dissociates into ions in solution ) attached to, or “ in complex with, ” a surfactant, a substance that lowers the surface tension between two liquids ( or between a liquid and a solid ). these liquid systems, called polyelectrolyte - surfactant complexes ( pscs ), are good platforms for scientists to study how polymers and small molecules bind and also how they behave in solution. looking ahead, scientists are targeting pscs as a route toward creating functional materials with specific jobs, such as nanostructures for drug delivery. but investigating psc behavior can be difficult because the complexes self - assemble into phases of many different structures, including cubic assemblies of various - sizes, hexagonal assemblies of cylinders, and stacks. scientists want to find a method that will allow them to “ dial in " a preferred phase. in a significant step toward this ability, researchers working at nsls recently mapped out the full phase diagrams of a new, enhanced type of psc, determining all the possible phases given different solution concentrations. the group, which consists of researchers from stony brook university, nsls, and the university of massachusetts amherst, call their system an electrostatically self - assembled amphiphilic complex, or esa. “ my lab is interested in creating ordered nanoporous materials for applications in filters, catalysis and fuel - cell membranes, ” said the study ’ s corresponding scientist, helmut strey from stony brook university. “ this published work is the first step towards this goal by employing self - assembly to create porous materials with tunable pore size. ” in psc systems, the different phases are dictated mainly by spherical clusters of surfactant molecules, called micelles, which form when the surfactant is in solution.


- assembly to create porous materials with tunable pore size. ” in psc systems, the different phases are dictated mainly by spherical clusters of surfactant molecules, called micelles, which form when the surfactant is in solution. the phases are governed by the micelles ’ size and curvature, and how “ bendy " they are, and thus these are the characteristics the researchers need to control. at nsls, the group discovered that adding a cosurfactant called pentanol to the mix allows the surfactant micelles to loosen up. by then incorporating large amounts of an oily liquid called dodecane, the researchers caused each phase ' s unit cell ( the building block of the structure ) to nearly double in size. this degree of manipulation is a big step forward in the drive to understand self - assembly and use it to create new materials and technologies. said strey, “ the advantage of self assembly is that to make a material you just have to throw all the ingredients together and the material forms by itself. in the future, we will develop techniques to solidify our structures to create usable nanoporous materials. ” the scientists used x - rays to study the system in its various concentrations, employing an advanced technique that allows them to study many samples at once. this high throughput is achieved using a well plate scanner, a sample analysis system that combines a well plate — a tool that can hold many samples at once via with an array of small wells — with a motorized stage that can hold up to three well plates at a time and pass them through the x - ray beam. using this method scientists can study up to 1, 000 samples per day. “ this development is exciting because of the possibilities beyond this research, ” said co - author elaine dimasi, nsls physicist and group leader for the soft matter interface beamline at the future national synchrotron light source ii. “ as beams become smaller and data acquisition becomes faster, potentially every dataset becomes an ' image, ' whether we map out a sample in real space, in ' chemical composition ' space, like this work, or in processing space, such as by changing temperature or applying mechanical stress. “ once we can render such data in automatic ways, we have a way to ' light up ' regions of interest even in very large parameter spaces, and quickly hone in on the properties of interest to our applications. ” at nsls - ii, the third - generation light source that will succeed nsls, the


university of utah physicists invented a new " spintronic " organic light - emitting diode or oled that promises to be brighter, cheaper and more environmentally friendly than the kinds of leds now used in television and computer displays, lighting, traffic lights and numerous electronic devices. " it ' s a completely different technology, " says z. valy vardeny, university of utah distinguished professor of physics and senior author of a study of the new oleds in the july 13, 2012 issue of the journal science. " these new organic leds can be brighter than regular organic leds. " the utah physicists made a prototype of the new kind of led – known technically as a spin - polarized organic led or spin oled – that produces an orange color. but vardeny expects it will be possible within two years to use the new technology to produce red and blue as well, and he eventually expects to make white spin oleds. however, it could be five years before the new leds hit the market because right now, they operate at temperatures no warmer than about minus 28 degrees fahrenheit, and must be improved so they can run at room temperature, vardeny adds. vardeny developed the new kind of led with tho d. nguyen, a research assistant professor of physics and first author of the study, and eitan ehrenfreund, a physicist at the technion - israel institute of technology in haifa. the study was funded by the u. s. national science foundation, the u. s. department of energy, the israel science foundation and u. s. - israel binational science foundation. the research was part of the university of utah ' s new materials research science and engineering center, funded by the national science foundation and the utah science technology and research initiative. the evolution of leds and oleds the original kind of leds, introduced in the early 1960s, used a conventional semiconductor to generate colored light. newer organic leds or oleds – with an organic polymer or " plastic " semiconductor to generate light – have become increasingly common in the last decade, particularly for displays in mp3 music players, cellular phones and digital cameras. oleds also are expected to be used increasingly for room lighting. big - screen tvs with existing oleds will hit the market later this year. the new kind of oled invented by the utah physicists also uses an organic semiconductor, but isn ' t simply an electronic device that stores information based on the electrical charges of electrons.


or antiparallel. two advances make new kind of organic leds possible in the new study, the physicists report two crucial advances in the materials used to create " bipolar " organic spin valves that allow the new spin oled to generate light, rather than just regulate electrical current. previous organic spin valves could only adjust the flow of electrical current through the valves. the first big advance was the use deuterium instead of normal hydrogen in the organic layer of the spin valve. deuterium is " heavy hydrogen " or a hydrogen atom with a neutron added to regular hydrogen ' s proton and electron. vardeny says the use of deuterium made the production of light by the new spin oled more efficient. the second advance was the use of an extremely thin layer of lithium fluoride deposited on the cobalt electrode. this layer allows negatively charged electrons to be injected through one side of the spin valve at the same time as positively charged electron holes are injected through the opposite side. that makes the spin valve " bipolar, " unlike older spin valves, into which only holes could be injected. it is the ability to inject electrons and holes at the same time that allows light to be generated. when an electron combines with a hole, the two cancel each other out and energy is released in the form of light. " when they meet each other, they form ' excitons, ' and these excitons give you light, " vardeny says. by injecting electrons and holes into the device, it supports more current and has the ability to emit light, he says, adding that the intensity of the new spintronic oleds can be a controlled with a magnetic field, while older kinds require more electrical current to boost light intensity. existing oleds each produce a particular color of light – such as red, green and blue – based on the semiconductor used. vardeny says the beauty of the new spin oleds is that, in the future, a single device may produce different colors when controlled by changes in magnetic field. he also says devices using organic semiconductors are generally less expensive and are manufactured with less toxic waste than conventional silicon semiconductors. university of utah : http : / / www. unews. utah. edu / this press release was posted to serve as a topic for discussion. please comment below. we try our best to only post press releases that are associated with peer reviewed scientific literature. critical discussions of the research are appreciated. if you need help finding a link to the original


today, quality control and the desire for absolute safety have contributed to the introduction of numerous sensors in our lives. optical technologies have played an increasingly important role in this development because they combine the advantages of a small design, reduced production costs, fast measurement speeds, high precision, reliability, and non - contact measurements across large distances. a position - sensitive detector ( psd ) should be your first choice in sensors when determining the center of a beam spot. psds function locally analogously ; they interpret the current produced by a photodiode. a position - sensitive detector ( psd ) should be your first choice in sensors when determining the center of a beam spot. psds function locally analogously ; they interpret the current produced by a photodiode. this current is divided into one or two resistive layers. the advantages of this simple design are its stability and reliability. the electronics required to process the analog output signal are relatively simple and can be assembled inexpensively. unmatched speed and resolution a psd just determines the position of the center of incoming light, but it does so within nanoseconds and at a sub - nanometer resolution. it achieves a measurement tolerance of approximately 0. 1 %. the dynamic range of the light intensity stretches across several orders of magnitude. the accuracy can be significantly increased if reference points are saved in a value table. the optical components used together with the sensor usually introduce measurement errors ; however, if appropriate corrections are incorporated into the value table, it is possible to compensate for these errors to a large extent. because the psd gains its position information from the photocurrents of the diodes, methods of operation used in normal photodiodes can be used here as well. this includes, for example, the modulation of light to eliminate interference by ambient light. psds can be manufactured in any shape. some unusual designs include, for example, helix - shaped, circular, or spherical forms for 2d and 3d angular measurements. entire arrays of psds were developed for some applications ( e. g., surface tests ). versatile applications for psds examples of applications include alignment systems in which the position of a reference laser beam is measured relative to the psd. this principle is used in many different areas – from bridge construction to optical benches. as psds can be produced to operate at very low temperatures ( such as in liquid nitrogen ), this alignment method is also used in infrared optics because here the infrared radiation of a psd has to be kept to a minimum. one weakness of ps


from : cathy danielson ( firstname. lastname @ example. org ) date : tue jun 17 2003 - 13 : 34 : 40 edt next message : jesserogue @ aol. com : " [ channel - talkchemistry ] atoms and molecules lesson ideas " i have my students create their own periodic table using element cards, much like the teacher in the program did. i have found my students somewhat confused - just as his students were! i don ' t know if this is my own idea or if i borrowed it from someone else, but i have had much more success when using pieces of colored paper as an introduction to the element card activity. i give each group of 3 - 4 students a set of paper pieces ( usually 6 colors with 5 sizes of each color - all in a zip - lock plastic bag ). i instruct the students to arrange the paper pieces in a logical order. most students arrange by both size ( which can be compared to atomic number ) and color ( which can be compared to color ). many also arrange in a " rainbow order " which can also be related to the idea of periods running from most reactive metal to noble gases. the element card activity goes much better when students have some basic idea of organization already in their head. this activity also works well in my freshman physical science classes. do you yahoo!? sbc yahoo! dsl - now only $ 29. 95 per month! channel - talkchemistry mailing list


color and vision visit the physics classroom ' s flickr galleries and enjoy a photo overview of the topic of light and color. color television explore how a television uses r, g, and b pixels to produce... millions of colors. phet simulation : color vision mix r, g and b light with varying intensities using this java applet from phet. mixing colors mix light colors at the ontario science center and learn about the principles of color addition. looking for a lab that coordinates with this page? try the color addition lab from the laboratory. curriculum corner learning requires action. give your students this sense - making activity from the curriculum corner. color addition the red - green - blue color swatches on this page provide a great opportunity to demonstrate addition of r, g, and b in varying amounts. treasures from tpf need ideas? need help? explore the physics front ' s treasure box of catalogued resources on visible light and color. general atomics sciences : chromatics - the science of color this downloadable, 100 - plus page book discusses various aspects of light production in the visible spectrum and color addition and subtraction. general atomics sciences : it ' s a colorful life deepen your understanding of color with this free, downloadable book on color ; contains theory and ideas for labs. color perception, like sound perception, is a complex subject involving the disciplines of psychology, physiology, biology, chemistry and physics. when you look at an object and perceive a distinct color, you are not necessarily seeing a single frequency of light. consider for instance that you are looking at a shirt and it appears purple to your eye. in such an instance, there may be several frequencies of light striking your eye with varying degrees of intensity. yet your eye - brain system interprets the frequencies that strike your eye and the shirt is decoded by your brain as being purple. the subject of color perception can be simplified if we think in terms of primary colors of light. we have already learned that white is not a color at all, but rather the presence of all the frequencies of visible light. when we speak of white light, we are referring to roygbiv - the presence of the entire spectrum of visible light. but combining the range of frequencies in the visible light spectrum is not the only means of producing white light. white light can also be produced by combining only three distinct frequencies of light, provided that they are widely separated on the visible light spectrum. any three colors ( or frequencies ) of light that produce white light when combined with the


planning of the converged solution. 5. 11 realization of the ideas. 5. 12 assessment against problem statement and verification. chapter 6 : imagination, visualization, graphical representations and communication. 6. 4 engineering drawings. 6. 5 realistic drawings. 6. 6 perspectives and location of objects. 6. 7 determining depth in perspectives : scale factors. 6. 8 drawing perspectives. 6. 10 put - it - in - the - box technique. part 2 : the design environment. chapter 7 : design considerations, decisions, and consequences. 7. 5 material selection. 7. 6 methods of fabrication. 7. 7 physical and structural standards. 7. 8 functional standards and expectations. 7. 12 company image and mission. 7. 15 styling, shape, aesthetics, and packaging. 7. 17 human factors. 7. 18 environmental effects ( on the design and caused by the design ). 7. 22 life expectancy. 7. 23 ethical issues. 7. 24 patents and other intellectual property. 7. 25 legal matters. chapter 8 : human factors in design. 8. 2 human - machine interface. 8. 3 anthropometric data. 8. 4 the civilian american and european surface anthropometry resource ( caesar ) project. 8. 5 basic applications of the anthropometric data. 8. 6 software - based application of the anthropometric data. 8. 7 inside - out versus outside - in design. 8. 8 deficiencies and shortcomings of anthropometric data. 8. 9 what can be done. 8. 10 left - handed versus right - handed users. 8. 11 sensory information exchange. 8. 12 human - machine interface. 8. 13 physical and psychological characteristics of humans. 8. 14 visual characteristics of humans. 8. 15 auditory characteristics of humans. 8. 16 temperature and humidity. 8. 17 acceleration capabilities and limitations. 8. 18 psychological factors. 8. 19 human factors and safety. 8. 20 occupational injuries. 8. 21 human factors and maintainability. chapter 9 : aesthetics of design. 9. 2 aesthetic elements of design. 9. 3 form and function relationship. 9. 6 harmony, unity. 9. 12 art and technology : a reciprocal relationship. chapter 10 : material properties, selection, and processing. 10. 2 material properties. 10. 3 types of materials. 10. 4 metals, alloys. 10. 6 plastics, polymers, and synthetic materials. 10. 7 other materials. 10. 8 material selection. 10. 9 material


and processing. 10. 2 material properties. 10. 3 types of materials. 10. 4 metals, alloys. 10. 6 plastics, polymers, and synthetic materials. 10. 7 other materials. 10. 8 material selection. 10. 9 material processing and manufacturing. 10. 10 design for manufacturing ( dfm ) and design for assembly ( dfa ). 10. 11 design for disassembly ( dfd ). 10. 12 computer aided manufacturing ( cam ) and computer integrated ( ctm ). 10. 13 rapid prototyping. 10. 14 lean production. chapter 11 : economics of design. 11. 2 value of a product or system. 11. 3 global economics models. 11. 4 costs, revenues, and profits. 11. 5 cost breakdown of products and systems. 11. 6 product life span. 11. 7 engineering economy. chapter 12 : quality in design. 12. 2 definition of quality. 12. 3 historical background. 12. 4 statistical quality control. 12. 6 what is quality? 12. 7 the concept of zero defects. 12. 8 deming ’ s principles. 12. 9 taguchi methods. 12. 10 design of experiments 12. 12 lean production. chapter 13 : design and product liability. 13. 2 product liability : history and background. 13. 3 the legal system of the united states. 13. 4 major administrative laws related to product liability. 13. 5 some basic definitions of terms. 13. 6 basic theories of product liability law. 13. 7 who may be held liable. 13. 8 origins of products defects and liability. 13. 9 the unreasonably dangerous product. 13. 10 reducing product liability risk. 13. 11 failure mode and effect analysis ( fmea ). 13. 12 code of ethics for engineers. 13. 13 standards and codes. 13. 14 what protection does the designer have? chapter 14 : intellectual property protection : patents, trademarks, copyrights. 14. 3 what is a patent? 14. 4 utility patents. 14. 5 requirements for utility patents. 14. 6 to patent or not to patent : that is the question. 14. 7 process of patenting. 14. 9 application and maintenance fees. 14. 10 inference and diligence. 14. 11 provisional patent application. 14. 12 infringement of patents. 14. 13 patent marking and patent pending. 14. 14 international patents. 14. 15 documentation and record keeping. 14. 16 licenses and assignments. 14. 17 sample patent. 14


is erroneous. einstein never wasted his time. ” einstein ’ s split with mainstream physics came at the very height of his career. in 1927, when he was 48, the world ’ s leading physicists gathered at a conference in brussels to debate an issue that remains contentious to this day : what does quantum mechanics have to say about reality? einstein had won the nobel prize in physics for research that showed that light consists of particles of energy — research that laid the groundwork for quantum mechanics. yet he dismissed the new theory out of hand. at the conference, he clashed with the great danish physicist niels bohr, launching a feud that would last until einstein ’ s death in 1955. bohr championed the strange new insights emerging from quantum mechanics. he believed that any single particle — be it an electron, proton, or photon — never occupies a definite position unless someone measures it. until you observe a particle, bohr argued, it makes no sense to ask where it is : it has no concrete position and exists only as a blur of probability. einstein scoffed at this. he believed, emphatically, in a universe that exists completely independent of human observation. all the strange properties of quantum theory are proof that the theory is flawed, he said. a better, more fundamental theory would eliminate such absurdities. “ do you really believe that the moon is not there unless we are looking at it? ” he asked. “ he saw in a way more clearly than anyone else what quantum mechanics was really like, ” british physicist julian barbour says. “ and he said, ‘ i don ’ t like it. ’ ” in the years after the conference in brussels, einstein leveled one attack after another at bohr and his followers. but for each attack bohr had a ready riposte. then in 1935 einstein devised what he thought would be the fatal blow. together with two colleagues in princeton, nathan rosen and boris podolsky, he found what appeared to be a serious inconsistency in one of the cornerstones of quantum theory, the uncertainty principle. formulated in 1927 by the german physicist werner heisenberg, the uncertainty principle puts strict limits on how accurately one can measure the position, velocity, energy, and other properties of a particle. the very act of observing a particle also disturbs it, heisenberg argued. if a physicist measures a particle ’ s position, for example, he will also lose information about its velocity in the process. einstein, podolsky, and rosen disagreed, and they suggested


a particle also disturbs it, heisenberg argued. if a physicist measures a particle ’ s position, for example, he will also lose information about its velocity in the process. einstein, podolsky, and rosen disagreed, and they suggested a simple thought experiment to explain why : imagine that a particle decays into two smaller particles of equal mass and that these two daughter particles fly apart in opposite directions. to conserve momentum, both particles must have identical speeds. if you measure the velocity or position of one particle, you will know the velocity or position of the other — and you will know it without disturbing the second particle in any way. the second particle, in other words, can be precisely measured at all times. einstein and his collaborators published their thought experiment in 1935, with the title “ can quantum - mechanical description of physical reality be considered complete? ” the paper was in many ways einstein ’ s swan song : nothing he wrote for the rest of his life would match its impact. if his critique was right, quantum mechanics was inherently flawed. bohr argued that einstein ’ s thought experiment was meaningless : if the second particle was never directly measured, it was pointless to talk about its properties before or after the first particle was measured. but although quantum physics eventually carried the day, it wasn ’ t until 1982, when the french physicist alain aspect constructed a working experiment based on einstein ’ s ideas, that bohr ’ s argument was vindicated. in 1935 einstein was convinced that he had refuted quantum mechanics. and from then until his death 20 years later, he devoted nearly all his efforts to the search for a unified field theory.


per ` i * od " ic (? ), a. [ pref. per - + iodic. ] chem. pertaining to, derived from, or designating, the highest oxygen acid ( hio ) of iodine. © webster 1913. pe ` ri * od " ic (? ), pe ` ri * od " ic * al (? ), a. [ l. periodicus, gr. : cf. f. p ' eriodique. ] of or pertaining to a period or periods, or to division by periods. the periodicaltimes of all the satellites. sir j. herschel. performed in a period, or regular revolution ; proceeding in a series of successive circuits ; as, the periodical motion of the planets round the sun. happening, by revolution, at a stated time ; returning regularly, after a certain period of time ; acting, happening, or appearing, at fixed intervals ; recurring ; as, periodical epidemics. the periodic return of a plant ' s flowering. to influence opinion through the periodical press. of or pertaining to a period ; constituting a complete sentence. periodic comet astron., a comet that moves about the sun in an elliptic orbit ; a comet that has been seen at two of its approaches to the sun. - - periodic function math., a function whose values recur at fixed intervals as the variable uniformly increases. the trigonomertic functions, as sin x, tan x, etc., are periodic functions. exponential functions are also periodic, having an imaginary period, and the elliptic functions have not only a real but an imaginary period, and are hence called doubly periodic. - - periodic law chem., the generalization that the properties of the chemical elements are periodic functions of their atomic wieghts. " in other words, if the elements are grouped in the order of their atomic weights, it will be found that nearly the same properties recur periodically throughout the entire series. " the following tabular arrangement of the atomic weights shows the regular recurrence of groups ( under i., ii., iii., iv., etc. ), each consisting of members of the same natural family. the gaps in the table indicate the probable existence of unknown elements. a similar relation had been enunciated in a crude way by newlands ; but the law in its effective form was developed and elaborated by mendelejeff, whence it is sometimes called mendelejeff


msp : middleschoolportal / energy transfers and transformations : sparking student interest from middle school portal energy transfers & transformations : sparking student interest - introduction as we each move through our day, we are constantly witnessing and experiencing changes in energy. most of us just don ’ t notice. it starts when the alarm clock goes off and continues as we power up with breakfast, do our morning workout, and drive to school. even the leaves on plants are quietly converting solar energy into chemical energy! it is easy to get hung up with the concept of energy. even nobel laureate richard feynman ( 1995, pgs. 71 - 72 ) found it an abstract topic. it is important to realize that in physics today, we have no knowledge of what energy is. we do not have a picture that energy comes in little blobs of a definite amount. it is not that way. however, there are formulas for calculating some numerical quantity and when we add it together it gives " 28 " — always the same number. it is an abstract thing in that it does not tell us the mechanisms or the reasons for the various formulas. the purpose of energy transfers & transformations is to provide you with resources that help your students understand how energy moves and changes. we followed the recommendations of the national science education standards ( nrc, 1996 ) that middle school students experience energy moving from place to place and changing forms. students should see how energy can cause objects to move. when we raise students ’ awareness of the energy movements and conversions around them in their daily lives, energy becomes more real. the terms energy transfer and energy transformation are often used interchangeably. here we will refer to the movement of one form of energy from place to place as energy transfer and the conversion of energy from one form to another as energy transformation. if we are talking about heat being conducted from a warm to cool area, that would be energy transfer. when we refer to electrical energy being converted to light, we use the term energy transformation. we ' ve selected resources that give you an idea of middle school energy concepts and activities. they are not meant to meet all of your teaching needs, but will perhaps spark some ideas for you and your students to convert the abstract to the concrete. references : feynman, richard p. ( 1995 ). six easy pieces : essentials of physics explained by its most brilliant teacher. cambridge, ma : perseus books. national research council. ( 1996 ). national science education standards. washington, dc : author. background information


. ( 1995 ). six easy pieces : essentials of physics explained by its most brilliant teacher. cambridge, ma : perseus books. national research council. ( 1996 ). national science education standards. washington, dc : author. background information for teachers if you didn ’ t read the quote by richard feynman in the introduction, take a second to do that. done? now, breathe a sigh of relief. even physicists of the nobel laureate type don ’ t completely understand energy. that said, we encourage you and your students to dig into this topic with gusto. for guidance on how to sequence your lessons, consider the relationships among energy transfer concepts. this tool - - nsdl strand map service - - maps a sequence of learning goals from grades k - 12 and lists resources related to specific science and math concepts. the maps illustrate connections between concepts as well as how concepts build upon one another across grade levels. an image of the grade 6 - 8 section of the energy transformations map appears below. the energy transformations map is one of sixteen maps under the physical setting heading. clicking on a concept ( aka learning goal within a gray box ) will show nsdl resources relevant to the concept, as well as information about related aaas project 2061 benchmarks and national science education standards. move the pink box in the lower right hand corner of the page to see the grades 6 - 8 learning goals. below is a handful of informational resources that you and your students can consult to help underpin your exploration of energy transformations. use them to supplement the materials you already have. for each resource, we ’ ve indicated if it is appropriate for student use, teacher use, or for use by both groups. you ’ ll find resources about potential and kinetic energy and other forms of energy, including one resource focused just on light. introduction to energy are you a little confused about types of energy and their transformations? teachers and students can learn how different types of energy are categorized into potential and kinetic forms. each brief paragraph explains how the form of energy is stored or released. small icons are used to show how energy is transformed from one form to another. for example, readers can see that the chemical energy in gasoline is transformed into energy of motion in a car. at the bottom of the document you will find additional information about renewable and nonrenewable sources of energy. types of energy here ’ s a reading that can introduce students to a variety of energy forms and to some of the energy transformations that humans use to meet our energy needs.


how to make them. if the students are not going to construct the racers, they can consider what happens in the video to answer the discussion questions. the second part is three paragraphs of background information that are appropriate for either you or your students. the information contains real - world examples of potential and kinetic energy. if the students are doing this as a discovery activity, you will want to have them read this section after they are done with the spool racer. even though the children in the video look to be in elementary school, the discussion questions and the activity are very appropriate for middle school students. a link to the related standards is provided. energy at play students learn about potential and kinetic energy firsthand in this design challenge. the challenge is two - tiered : students design a toy that can propel a ball first a short and then a longer distance. ( consider converting the distances so that they are both in the metric system. ) in between the two tasks, the teacher demonstrates and facilitates a discussion about the conservation of energy. the packet offers substantial teacher support material, including materials lists, teaching points and related questions to ask students about the energy concepts involved in their designs, and lists of design constraints to share with students. although grades 3 - 6 are the target audience, the challenge ’ s content aligns well with the national physical science standards for grades 5 - 8. note that gravitational and elastic potential energy — the forms of potential energy addressed here — are not the only kinds of potential energy. atmospheric processes : radiation need some experience doing quantitative science experiments? in these activities, students take measurements, graph the results, and draw conclusions. they even generalize their results to real - world applications! after explaining the differences between conduction, convection, and radiation, this teacher guide offers activities in which the students learn first - hand the relationship between the color or texture of an object and its ability to absorb energy. students first measure, at one - minute intervals for ten minutes, the temperature of three materials ( water, light soil, and dark soil, or materials chosen by the teacher or students ) heated by a reflector lamp. the students also measure the temperature of the three materials as they cool for ten minutes. students consider that the earth is made of a variety of materials that absorb heat unevenly. what impact do you think this has on the earth ’ s atmosphere? good way to link energy transfer to weather and climate, isn ’ t it? testing materials for thermal conductivity we didn ’ t select this heat conduction activity because


unevenly. what impact do you think this has on the earth ’ s atmosphere? good way to link energy transfer to weather and climate, isn ’ t it? testing materials for thermal conductivity we didn ’ t select this heat conduction activity because it is new and different. that said, this version did catch our eye for a number of reasons : ( 1 ) the student activity sheet is written clearly, and the activity is well - designed ; ( 2 ) short answer and multiple choice assessment questions and answers are included ; and ( 3 ) the producers of the lesson plan, the texas state energy conservation office, have set the activity in a real - world context - - that of home insulation. a required reading from the same site is the basis for some of the assessment questions, a few of which are specific to texas. the teacher instructions come first in the packet, so don ’ t be confused if you see assessment answers before spotting the questions. dancing penny with the most basic of equipment ( a coin, a bottle, and water or oil ) and this demonstration, you can get students thinking about the transfer of heat and the cascading effects of that transfer. the activity, part of the well - known whelmers set, comes with all the teacher supports you ’ d expect, including presentation notes, standards correlations, an explanation of the demonstration ’ s science content, and an assessment idea. the demo calls on students to consider the conduction of heat, the chain of energy conversions leading up to the heat transfer, and the relationship between the temperature and pressure of a gas. smartr : virtual learning experiences for students visit our student site smartr to find related virtual learning experiences for your students! the smartr learning experiences were designed both for and by middle school aged students. students from around the country participated in every stage of smartr ’ s development and each of the learning experiences includes multimedia content including videos, simulations, games and virtual activities. visit the virtual learning experience on energy. the funworks visit the funworks stem career website to learn more about a variety of science - related careers ( click on the science link at the bottom of the home page ). national science education standards these excerpts from the national science education standards ( nses ) relate to the study of energy in middle school. physical science as a result of activities in grades 5 - 8, all students should develop an understanding of : transfer of energy - energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei


school. physical science as a result of activities in grades 5 - 8, all students should develop an understanding of : transfer of energy - energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. energy is transferred in many ways. - heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature. - light interacts with matter by transmission ( including refraction ), absorption, or scattering ( including reflection ). to see an object, light from that object - - emitted by or scattered from it - - must enter the eye. - electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced. - in most chemical and nuclear reactions, energy is transferred into or out of a system. heat, light, mechanical motion, or electricity might all be involved in such transfers. - the sun is a major source of energy for changes on the earth ' s surface. the sun loses energy by emitting light. a tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. the sun ' s energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation. author and copyright carolee barber and judy ridgway, formerly of eisenhower national clearinghouse for science and mathematics education, instructional resources. carolee barber was a science education resource specialist at enc. she has taught a variety of science courses and worked for a conservation organization. judy ridgway was enc ' s assistant director of instructional resources. she is a veteran educator in the biological sciences. please email any comments to firstname. lastname @ example. org. connect with colleagues at our social network for middle school math and science teachers at http : / / msteacher2. org. copyright march 2005 - the ohio state university. last updated september 19, 2010. this material is based upon work supported by the national science foundation under grant no. 0424671 and since september 1, 2009 grant no. 0840824. any opinions, findings, and conclusions or recommendations expressed in this material are those of the author ( s ) and do not necessarily reflect the views of the national science foundation.


conducted by marty mulvihill, uc berkeley center for green chemistry and the american chemical society, green chemistry institute. this half - day workshop will introduce the concepts of green chemistry, show real - world examples, and make the business case for green chemistry. learn about safer chemical alternatives, metrics for comparing the “ greenness ” of chemicals and processes ; and resources available from acs gci and wa state department of ecology. the course will provide examples of practical tools for implementing green chemistry practices. this presentation will explore how the principles of green chemistry can be applied to the development of sustainable nanotechnology. both nanotechnology and green chemistry have promised to do more with less and have been driven by innovation. proponents of both technologies promise to address the needs of a growing global population. nanotechnology has promised advances in catalysis, energy production, and human health by harnessing the novel properties of materials that occur at the nanoscale. green chemistry has promised to address many of the same challenges by minimizing the adverse health effects of chemicals while maximizing the efficiency of their production. my presentation aims to highlight an approach to nanotechnology that integrates the principles of green chemistry. examples will include the design and synthesis of nanomaterials, the development of an arsenic sensor, and studies examining the environmental fate of engineered nanoparticles. these case studies exemplify an approach to nanotechnology that promotes innovative solutions and collaborative approaches to problem solving. conducted by marty mulvihill, uc berkeley center for green chemistry and the acs green chemistry institute. this half - day advanced workshop will delve more deeply into case studies and tools of green chemistry. this course will be interactive and steered by dialogue among attendees. attendees should have a basic understanding of green chemistry, the principles of green chemistry, industrial applications and metrics for determining the greenness of chemicals or attendance at green chemistry 101. diane barton : treaty rights and toxics in fish ( view presentation ) at the time of the 1855 treaties when the tribes and bands that are now the yakama nation, the confederated tribes of warm springs, the confederated tribes of the umatilla indian reservation and the nez perce tribe, ceded millions of acres in return for promises that included the right to take fish at all usual and accustomed place, the tribes did not anticipate the industrial development that would pollute their waters and consequently their food sources with toxic substances. tribes today are working together to protect their rights to clean and healthy traditional food sources


application layer ( layer 5 ). it works by encapsulating the packet, payload ( original data ) and header within a udp ( universal data protocol ) datagram. datagrams are basically a package containing a short message. for example, a series of datagrams form the basis for streaming audio and video technologies. the current version is l2tpv3 which provides improved performance and compatibly with other transport services. one more protocol you should know is called ipsec, which is short for ip security. this is typically used in conjunction with a tunneling protocol, particularly l2tp as a means to provide secure authentication and encryption services. when the two protocols are used together the protocol is called l2tp / ipsec. in practice, the tunneling process begins by establishing the virtual connection between the client and host systems. the implementation of creating the vpn is typically done through software and / or hardware applications. a popular example of ip tunneling is the virtual private network ( vpn ), which provides remote users the ability to gain access to their internal network ( intranet ) and network resources ( printers, etc. ) as if they were connected in their offices. the remote user initiates a typical vpn session with a software client that requires you log in with your username, password, etc. the host end of the vpn manages the task of accepting requests to establish the connection and verifying the user login and security information. once the user information has been accepted the tunneled connected is established and remains connected until either the user ( or administrator ) chooses to stop it or the host system has provisions to drop the connection when not in use for a preset amount of time. while tunneling provides a better experience for the remote user, it also offers a much higher level of security for the host network since the connection can ' t be established without going through some level of security check. creating a tunneled connection is easy or cheap ( even free ) with the use of software applications easily downloaded from the web. some of the more popular ones include zebedee, nest and barracuda. a web search for “ ip tunneling software ” will direct you to these and a host of other solutions you can use to create your own custom ip tunnel. most of these also have detailed user guides to help you achieve your goal and make a handy addition to your new toolbox. mcnamara is president of applied wireless, cape coral, fl. acceptable use policy blog comments powered by dis


definitions of ring : - noun : jewelry consisting of a circlet of precious metal ( often set with jewels ) worn on the finger example : " she had rings on every finger " - noun : a square platform marked off by ropes in which contestants box or wrestle - noun : a characteristic sound example : " it has the ring of sincerity " - noun : the sound of a bell ringing example : " the distinctive ring of the church bell " - noun : a toroidal shape example : " a ring of ships in the harbor " - noun : a strip of material attached to the leg of a bird to identify it ( as in studies of bird migration ) - noun : a rigid circular band of metal or wood or other material used for holding or fastening or hanging or pulling - noun : ( chemistry ) a chain of atoms in a molecule that forms a closed loop - noun : an association of criminals - verb : sound loudly and sonorously - verb : make ( bells ) ring, often for the purposes of musical edification example : " ring the bells " - verb : attach a ring to the foot of, in order to identify example : " ring birds " - verb : ring or echo with sound - verb : get or try to get into communication ( with someone ) by telephone - verb : be around - name : a surname ( common : 1 in 16666 families ; popularity rank in the u. s. : # 2137 ) search for ring at other dictionaries : onelook, answers. com, merriam - webster " works flawlessly! " : rhymezone apps for iphone / ipad and android! help, feedback, customize, android app, iphone / ipad app copyright © 2013 datamuse


what makes you, you? who am i? investigates everyone ’ s favourite subject – themselves. step into a whole new world and explore the science of our changing climate... feel the impact of a saturn v rocket launch, ride the lunar rover and discover the smell of space. learn how mechanical power replaced animal power in this history of farming. the antenna gallery brings you science news from every angle – from headline grabbing gadgets to hot topics. explore the world of materials, from the leading edge of scientific innovation to new insights into everyday objects. watch the video on babbage ' s ingenious machine, or learn about the mathematical instruments used before the invention of computers. will your ideas today change the world tomorrow? discover the importance of energy in this fascinating gallery. the ingenious use of steam to generate power helped britain become the world ’ s first industrial nation. ernie was the first machine to generate random numbers for the premium bonds. find out how he captured the public ’ s imagination and provides a link to colossus, the first digital electronic computer. share the dreams of the flight pioneers : see the development of aviation from its tentative beginnings to the modern era of mass air travel. have you ever watched the red arrows and been itching to get you hand on the controls? find out how it felt to be a doctor or patient at different times in history, or in different cultures. unravel the connection between apricot tins and kidney machines, in this provocative exhibition on developments in twentieth century medicine. decide whether new technological developments - such as space tourism to male pregnancy - should or should not go ahead. launchpad - the science museum ' s most popular gallery. explore science and technology first - hand with 50 hands - on exhibits and shows. this unique, breathtaking gallery chronologically presents 150 of the most significant items from the science museum ' s collections from 1750 to 2000. the mathematics gallery exhibits mathematical instruments and models from the seventeenth century to present day. small exhibition exploring some of the stories, tools and puzzles that have engaged british psychologists during the twentieth century. fly in the cockpit of a red arrows jet in our 3d flight simulation theatre. see more than 5000 objects from around the world illustrating the history of medicine in western and non - western cultures. see king george iii ' s unrivalled and beautiful collection of contemporary scientific apparatus. see the extraordinary range of labour - saving devices in this intriguing technological guide to the development of the modern home. trace the story of the space rocket. find out how we


used repeatedly as students engage in inquiry with magnets. such clarity is not evident in english / language arts standards where literary texts are the focus ( marzano, 2004 ). literary texts often present rare words that are unique to a particular story. each text has its own rare words. thus, students cannot become proficient in the meaning of these words through repetition. these rare words, however, represent specific elements of stories. an author of a literary text chooses a word intentionally from the extended vocabulary to communicate an action, a social relationship, the feature of a place or event, and the feelings and attitudes of characters. in geeks, for example, katz ( 2000 ) could have used numerous words to describe the condition of the furniture within the apartment of his protagonists. however, by describing the beanbag chair as moldering, readers get a clear idea of the condition of the apartment. just as in mathematics where lessons build understanding for future problem solving, considerable time needs to be spent in developing the linguistic foundation of english vocabulary for the future reading of complex literary texts. this pattern of single - appearing, rare vocabulary does not only appear in narratives, though. it also appears in magazine articles on topics of science, history, and civics to describe traits, features, interactions, and contexts. this style also extends to full - length texts with a literary stance about technology and science ( e. g., geeks ) and history and political science ( e. g., a night to remember ). english learners need to become adept with such vocabulary for a variety of reasons, including the heavy presence of literary texts on assessments. analyses of two grade 6 – 8 texts from the ccss ’ s appendix b exemplar list — geeks and a night to remember ( ntr ) — demonstrate the two types of vocabulary instruction needed for proficient reading of literary texts : ( a ) general principles / strategies and ( b ) lessons with specific texts. both texts typify the literary texts offered as ccss exemplars. both have higher levels of extended vocabulary than other grade 6 – 8 exemplars ( see table 1 ), which is why these texts were selected for illustration in this text matters. analyses of these two texts show that, even in these vocabulary - dense texts, most words fall into particular groups — groups that share underlying features. | content area | | text | | core vocabulary ( % ) | | extended vocabulary ( % ) | | social studies | | a night to remember | | 92. 5 | | 7


we know that a single electron doesn ' t travel down the length of a wire, it ' s passed from atom to atom. true. that ' s why the light speed in a wire is lower than the light speed in a vacuum. i have not seen any evidence that there are a such thing as photons or that they travel through space. light is emitted by sources and exists in the form of electromagnetic waves, or photons. even though the latter is the name for the quantitzed elements that we measure when absorbed. it doesn ' t matter. what matters is, light somehow bridges the gap in a vacuum between object a and measurement device b. this exactly coincidences with our definition of travel. somehow denying this, and coming with some absurd philosophical point of view that this doesn ' t include traveling is absurd. what you can doubt, which is even part of relativity, is that any time passes from the frame of reference of the ' photon '. because there doesn ' t. but that ' s not the discussion right now, the one thing that is clear is that light travels. how else, could light be bended by a gravitational field? as far as i can tell, it could just as easily be atoms detecting and imitating one another in an orderly fashion, rather than massless intangible particle - waves transacting in a vacuum. in a vacuum there are no atoms. and if i follow you in your ridiculous standpoint, what you call " detecting one another " is called light, and this needs to bridge an amount of space, which is what we call travel. denying obvious real world results is a serious symptom of crankyness. not that you will ever admit this, even to yourself. does light look like it travels to you or does it look like you are seeing it right where it is? measurements show it starts and point a and can detected at point b. we call this phenomenon " movement ". as living members of the cosmos, are we not obligated to consider our own direct experience of phenomena as a factor in explaining that experience? no. our experience is a separate phenomenon. not to say that everything actually how it seems to us, but i would say that quite a bit can be explained better though first hand observation. it should not be disqualified. human observation or experience isn ' t disqualified. it is a separate phenomenon that is studied in a separate field, called psychology. there is no need whatsoever to connect two totally unrelated phenomena. our bodily detection and interpretation


observation. it should not be disqualified. human observation or experience isn ' t disqualified. it is a separate phenomenon that is studied in a separate field, called psychology. there is no need whatsoever to connect two totally unrelated phenomena. our bodily detection and interpretation devices are not fundamentally different from the mechanical ones that we created. we measure the behavior of the materials which we are using to do the experiment and their interactions with each other. light doesn ' t have to physically leave the atom doesn ' t mean it can ' t be measured, understood, and predicted as if it did. maybe nothing happens or exist at all, and we are connected to some sort of super computer that just make it ' as if ' things are happening while physically they are not. might be true, probably isn ' t. it ' s just another unprovable crackpot theory. yes. i probably know most of the same things that you know about photons, i ' m just interpreting that knowledge a different way. yes, in a totally nonsensical way, not related to science nor reality. i see photons as quantum events within matter here you prove you don ' t know that photons are matter and both are forms of energy. blablabla. wild, senseless speculation, not based on research, nor measurement. your observations are again scientifically meaningless. sorry, yet some more discussion, because i just can ' t stand your never ending stupidity. striping it doesn ' t make it any less true. not my problem if you don ' t like those observations.


an important concept that comes from sequences is that of series and summation. series and summation describes the addition of terms of a sequence. there are different types of series, including arithmetic and geometric series. series and summation follows its own set of notation that is important to memorize in order to understand homework problems. so a series is just the summation of a sequence. so a sequence is just a bunch of numbers in a row, a series is what happens when we add up all those numbers together. okay? so before me i have a general term for a sequence. a sub n is equal to n squared minus 1. and first we ' re asked to find the first four terms. okay? so in order to find the first term, we would find a sub 1 which happens when we plug in 1. 1 squared minus 1 that ' s just 0. so our first term is going to be 0. to find the second term we plug in 2. a sub 2 is equal to 2 squared. 4 - 1 which is going to give us 3. third term [ ib ] and repeat a sub 3 is 3 squared, 9 - 1 is 8. and the fourth term a sub 4, plug in 4. 4 squared, 16 - 1 is 15. so this right here is a sequence. it ' s 4 numbers written in order with commons in between. it ' s just a collection of numbers. find the sum of those first 4 terms. so basically we already found the 4 terms, all we have to do is add them together. 0 + 3 is 3 plus 8 is 11 plus 15 is 26. so 26 is then the series, okay? series is the way i remember it is, series is a shorter word therefore your answer should be shorter, one number. a sequence is a longer word, it ' s going to be a collection of data, a collection of numbers, okay? so basically all the series is is a summation of the sequence.


a failure due to insufficient sensitivity in the receiver. colonel dewitt ' s appreciation of the problem and personalsupervision were the driving forces that made the present experimentsuccessful. assisting lt. colonel dewitt were : e. k. stodola, dr. harold d. webb, herbert p. kauffman and the writer, all of evans signal laboratory. credit is also due the members of the antennaand mechanical design croup, research section, theoretical studiesgroup and others. the practical implications of radar contact with the moon are numerous. during the war the germans used the v2 rocket whichclimbed some 70 miles above the earth, and the future holds the unhappy prospect of missiles going far higher than this. the matter oftransmission of radio signals to great distances above the earth for detection and control of such weapons becomes a problem of military importance. further, the use of a reflector far beyond the earth forradio waves makes possible directmeasurement of the ability of radio waves to penetrate the ionosphere. a more complete investigation in this direction is indicated. the possibility of using the moon as the reflector for a part - time long - distance point - to - point communication system is also being considered, as well as using the moon as a target to measure field strength patterns. lt. colonel john h. dewitt jr., in charge of the project, a modified version of the scr - 271 early - warning radar used at pearl harbor. dewitt is the former chief engineer of wsm. the author, jack mofenson, adjusts the position of the waveform - monitoring stub. over this transmission line traveled the 3 - kw transmitted pulse and a millionth of a billionth watt echo. determination of requirements several of the constants which determine the maximum distance at which a radar set can detect targetsare peak transmitter power, radio - frequency of the transmitted signal, duration of the signal, receivernoise figure, and target echoing area. these constants, among others, are concisely summarized inwhat has been called the free - space radar equation. this equation has already been derived in electronics in this equation, r is the radar range at which a signal may be detected, pt is the transmitter power during the pulse, go, the transmitting antenna power gain, a. the absorption area of the receiving antenna, o the effective echoing area of the target, and p, the power of a barely discernible signal, on the same basis as


interval of 0. 25 sec. one of the shorting barsserves to short out the receiver input during transmission, and the other shorts out the transmitter during reception. keyer and indicator the visual indicator used is a nine - inch electrostatic cathode - ray tube, 9ep7, with a long - persistence screen. the electron beam is caused to scan the width of the tube, synchronouslywith the transmitted pulse, in 4 seconds, forming a linear time base. the persistence of the tube is long enough to retain the pattern for atleast two sweeps. the circuit employed to generate this sweep is a direct - coupled transitron sawtooth oscillator, described below. a pulse equivalent in time to the keying pulseis also generated by this circuit and is applied to the cathode of a low - level multiplier stage of the transmitter, causing it to conduct for the pulseduration and to drive the subsequentmultipliers. the time - base generator consists essentially of a high - gain pentode amplifier with capacitance couplingbetween plate and grid. the schematic is shown in fig. 7. the capacitance coupled path includes a cathode follower stage, the left hand sectionof v2 for the duration of the conduction cycle, the anode voltage ofthe pentode v1, drops and capacitorc1, begins to discharge through thetube. as the voltage on the platedrops the current flow in c1, drives the grid negative, tending to cut off the plate current. a condition of dynamic equilibrium then exists with the plate voltage dropping at a linear rate determined by r1, and c1, and thegrid being maintained at a constant voltage, since each decrement in plate voltage causes a corresponding dropon the grid which keeps the grid signal and hence the output of the tube substantially constant. the time constant of r1, c1, is chosen to cause c1, to become fully discharged during the cycle. when the plate voltage drops to the point where electrons from the cathode can no longer flow to it, anincrease in screen current occurs which rapidly decreases the screen voltage and correspondingly decreases the suppressor voltage. thisaction, which is cumulative, has the effect of suddenly cutting off theanode current. this causes the cathode current to be retarded by the suppressor grid and made to flow to the screen. a negative pulse appears atthe screen, and c1


is cumulative, has the effect of suddenly cutting off theanode current. this causes the cathode current to be retarded by the suppressor grid and made to flow to the screen. a negative pulse appears atthe screen, and c1, begins to chargethrough the cathode follower until a point is reached where theplate begins to draw current and the oscillator is recycled. the screen returns to its original voltage, and the plate voltage begins to fall. by suitable choice of r1, and c1, a range of from about 0. 1 to 3 cps is obtained. keying - voltage signals are derived from the differentiated output of the negative pulse appearing on the screen of the oscillator. this is used to trigger a multivibrator whose time constant is controllable by a variable 5 meg resistor, varying the output pulse width from 0. 02 to 0. 25 seconds. the addition of the cathode follower stage v2, was made to shorten the charge time of c1, by causing it to charge through the grid cathode space of the cathode follower. this reduces the return trace time. tube v3, serves as a degenerative phase - inverting amplifier to secure push - pull sweep voltage. the keyer multivibrator is a conventional cathode - coupled flip - flopcircuit with the initiating trigger applied as a positive pulse on the grid of the normally non - conducting section. a positive pulse varying in width from 0. 02 to 0. 85 seconds is obtained at the plate of the other section. this signal is applied to a normally cut off pentode whose loadimpedance is the cathode of the12. 388 me amplifier stage in the transmitter. for the duration of thisapplied signal, the plate of the amplifier is driven negative, taking thecathode of the keying tube down with it, thus causing it to conduct. the first echoes from the moon were received at moonrise on january 10, 1946. the indication was of the audible type in the form of a 180 - cycle beat note occurring 2. 5 seconds after transmission. although numerous observations have been made, both at moonriseand moonset, echo returns do not occur after every transmission. further measurements are needed before precise scientific conclusions can be drawn. ( 1 ) the radar equation, electronics p. 92, april 1945. page updated february 7, 2004 page created july 7, 1998? back to the


my saved article | atomic number : | | 33 | | atomic symbol : | | as | | atomic weight : | | 74. 9216 | | electron configuration : | | 2 - 8 - 18 - 5 | | melting point : | | 817 @ 28 atm. oc | | boiling point : | | sublimes @ 613oc | | uses : | | leds, deadly poison, semiconductors | history ( l. arsenicum, gr. arsenikon, yellow orpiment, identified with arenikos, male, from the belief that metals were different sexes ; arabic, az - zernikh, the orpiment from persian zerni - zar, gold ) sourceselemental arsenic occurs in two solid modifications : yellow, and gray or metallic, with specific gravities of 1. 97, and 5. 73, respectively. is believed that albertus magnus obtained the element in 1250 a. d. schroeder published two methods of preparing the element. arsenopyrite, ( fesas ) is the most common mineral from which, on heating, the arsenic sublimes leaving ferrous sulfide. propertiesthe element is a steel gray, very brittle, crystalline, semimetallic solid ; it tarnishes in air, and when heated is rapidly oxidized to arsenous oxide with the odor of garlic. handlingarsenic and its compounds are poisonous. arsenic is used in bronzing, pyrotechny, and for hardening and improving the sphericity of shot. compoundsthe most important compounds are white arsenic, the sulfide, paris green, calcium arsenate, and lead arsenate ; the last three have been used as agricultural insecticides and poisons. marsh ' s test makes use of the formation and ready decomposition of arsine. arsenic is finding increasing uses as a doping agent in solid - state devices such as transistors. gallium arsenide is used as a laser material to convert electricity directly into