with etymological history tracing the roots of the word " language " back to the middle english, old french and latin words for " tongue, " the very nature of language is tied to ideas of communication and expression. the common thread in all of the varying definitions of language is the concept of rifts between individual people, animals, even inanimate objects and how those gaps may best be bridged. inherent, however, in this idea of connection and communication is the separation that language may often imply by its very definition. beyond the conflict in definition, the idea of language raises serious questions in regard to where it falls in terms of medium, media, and mediator. the varying manifestations of language fit with different theories of media as demarcated by peirce, mcluhan, lacan, and saussure. in its most basic form, language is the primary mode of communication - - the expression of thoughts, feelings, and ideas to another. different subsets of language are defined by speech and vocal patterns, written systems, and the specialized vocabulary or phraseology required by particular professions, as well as non - verbal systems ranging from body language and kinesics to communication between animals to the modes and systems in which computers exchange data. one definition in the oxford english dictionary refers to language as " applied to methods of expressing the thoughts, feelings, wants, etc. otherwise than by words. " under this category may fall dance, facial expression, and other commonly accepted conditions [ see movement, face ]. one example of non - verbal communication worth considering is the cinema of the silent era [ see film ]. often, a dye wash would be employed to add visual interest to the black and white film stock used at the time. each color came to take on a specific meaning that would not change from film to film : blue came to mean night, red danger, pink dawn, etc. additionally, a stylized gesture system came to take the place of spoken words, allowing emotions to be understood without speech and only a periodic use of titles. language systems of this definition may be comprised of any socially understood practice : flowers may take on specific meanings, the movements of a lady ' s fan held a particular meaning in regency england, colors, movements, as well as what one may consider unarticulated sounds. this definition of language aligns itself most clearly with the writings of peirce. peirce ' s theories of semiotics examines the divisions of words and communications into doctrines by which a sign or idea is communicated to an


unarticulated sounds. this definition of language aligns itself most clearly with the writings of peirce. peirce ' s theories of semiotics examines the divisions of words and communications into doctrines by which a sign or idea is communicated to an outside party. each of the above mentioned methods of communication reflects to a varying degree what peirce sees as the key to sign theory : making known an abstraction ( peirce, 98 ). while utilizing diverse methods of embodying particular emotions and ideas, each of these subsets of language works toward what peirce defines as being a sign : each " stands for something, its object " ( peirce, 99 ). the object may be an emotion, a state of mind, or an idea. the method of representation may vary from speech to movement to creating a unified system of color. conversely, however, language may create barriers as it strives to create open communication. the oxford english dictionary defines language first and foremost as " the whole body of words and of methods of combinations of words used by a nation, people, or race. " exclusion of others becomes inherent in this conception of language. as it bonds some together, language may separate others along the lines of nationality, class, and race. speech patterns may reveal more about a person speaking than the words themselves. in shakespearean texts, the speeches ( and often, the dialogue ) of noble - born characters are written in blank verse. lower born characters, by the class expectations of elizabethan england, would ( with notable exceptions ) be uneducated, with comic relief found in their blatant malapropisms and grammatical blunders. unlike the rhythmic lines of their social superiors, these characters speak in prose, often using contemporary slang and more vulgar sexual innuendos. in this instance, the very nature of their speech is a language in and of itself, speaking far more than their words about their birth and position in society. by this definition, the role of language changes from a mediator of ideas between two parties, to approach marshall mcluhan ' s definition of media. to mcluhan, " the media is the message " ( mcluhan, 7 ). in this case, language has the ability to say more than the content of its words : the language itself is revealing. for mcluhan, media is never as isolated as one might think, and the very use of media itself becomes key to the content of what is being communicated. out of this theory comes mcluhan ' s famous


rather than neurons : when two elementary brain - processes have been active together or in immediate succession, one of them, on re - occurring, tends to propagate its excitement into the other. a chapter of james ' book is reprinted in volume 1 of anderson and rosenfeld ' s collection on neurocomputing ( anderson and rosenfeld, 1988 ). more than 50 years later, hebb ' s book ( hebb, 1949 ) of which two interesting sections are reprinted in the collection of anderson and rosenfeld ( 1988 ) was published. the historical context of hebb ' s postulate is discussed in the review of sejnowski ( 1999 ). in the reprint volume of anderson and rosenfeld ( 1988 ), articles of grossberg ( 1976 ) and bienenstock et al. ( 1982 ) illustrate the use of the rate - based learning rules discussed in section 10. 2. kohonen ' s book gives an overview of some mathematical results for several generic rate - based learning rules ( kohonen, 1984 ). for reviews on ( hippocampal ) ltp, see the book of byrne and berry ( 1989 ), in particular the articles of sejnowski and tesauro ( 1989 ) and brown et al. ( 1989 ). cerebellar ltd has been reviewed by daniel et al. ( 1996, 1998 ) and linden and connor ( 1995 ). further references and a classification of different forms of ltp and ltd can be found in the nice review of bliss and collingridge ( 1993 ). for the relation of ltp and ltd, consult artola and singer ( 1993 ). a modern and highly recommendable review with a focus on recent results, in particular on spike - time dependent plasticity has been written by bi and poo ( 2001 ). the theoretical context of spike - time dependent plasticity has been discussed by abbott ( 2000 ). © cambridge university press this book is in copyright. no reproduction of any part of it may take place without the written permission of cambridge university press.


from my research in hungary, one of the key things that has struck me is the way in which multiple representations and images are used to support the development of very abstract and complex mathematical ideas. this month ' s website will seek to illustrate this and offer some problems and resources that help students to develop notions of abstract mathematical ideas through exposure to a range of representations of them. this all sounds rather obscure and abstract in itself so let me illustrate this with two examples one from a class of 7 year old students and the other from a class of 15 year olds. for the younger students the concept under consideration was the idea of the number six. during the course of one lesson focused on this number, the children were offered a range of iconic and symbolic representations of six and asked to identify collections of six objects. this range comprised : pattern on a die, finger pattern, collections of objects, collections of actions, the cuisenaire rods, the ' number picture ', ( you can find them here doc. pdf ), dominoes with six spots, roman numerals, the symbol 6, number line, 6 o ' clock on an analogue clock face, coins. i would argue that this rich range of representations of 6 enabled the children to abstract a notion of the ' sixness ' of six that transcended the different representations. all the different representations have their value and potential applications : some stress the notion of a number representing a collection and so build from counting such as a collection of objects of actions ; others stress aspects of the structure of six such as the finger pattern which draws attention to six being one more than five ; others emphasise the wholeness of six as an entity that supports students away from a counting notion of number such as the symbol 6, the 6 cuisenaire rod or even potentially the die pattern that can be recognized without counting the spots ; some stress the place of six in the sequence of counting or natural numbers such as the number line. for the 15 year olds, the lesson that i observed was focused on the solution of simultaneous equations involving trigonometric functions. in this lesson the students were able to identify solutions to complicated pairs of equations through their knowledge of the meanings of the functions that were being considered. they were able to sketch the relevant graphs of the functions, consider their ranges and domains and use these ideas to produce solutions or to identify when solutions could not be found. this seemed to me to be linked to my observations of lessons with the younger children. in both cases the students had access to a range of representations,


ranges and domains and use these ideas to produce solutions or to identify when solutions could not be found. this seemed to me to be linked to my observations of lessons with the younger children. in both cases the students had access to a range of representations, images and mathematical models and were able to bring appropriate images to the problems with which they were presented. in some of our problems this month we offer a range of representations of mathematical ideas to work with, in others we offer a problem that lends itself to solution with one representation in mind. in all of the problems we are seeking to explore the power of a variety of representations, images and models with a view to supporting students in enriching their understanding of various abstract mathematical concepts through exposure to this variety. the aim of the exercise is to deepen students ' understanding of the abstract mathematical concepts involved in the process of generalizing from a variety of models and representations. matching numbers is an interactive game in which the task is to match different representations of numbers in pairs. in fact the set of cards has four possible representations of each of the numbers so children can discuss how each of those representations shows the number. when they have played the game themselves, they can make their own sets of number cards showing different representations of numbers using this blank set. how do you see it? is an activity with a difference in that as the children work on these they will have the opportunity to exhibit their own individual ways of thinking about simple calculations. the article referred to in the teachers ' notes will enable you to explore some of the findings about those calculations that children find more difficult because of the order of the information. let ' s divide up offers a story scenario in which three different conceptions of division are presented. we hope that children will be able to explore the different conceptions to deepen theri understanding of the mathematical operation of division. they may be encouraged to make up their own stories about that involve division conceived of as sharing, grouping, successive subtraction or the inverse of multiplication. matching fractions is another interactive game of memory but this time there are four representations of a number of fractions to match in pairs. we have a tendency to use pizzas as our main representation of fractions for young children and this can cause them problems with developing their conceptual understanding of fractions so this is a useful activity to tackle this as it offers a range of different representations including fractions of quantities bigger than one. once again children can create their own fraction representations and their own game using the blank card set. in


in his important and stimulating book, the meaning of the twentieth century. 1 recently the british economist barbara ward has employed this same image most effectively in a book entitled spaceship earth. 2 now that our astronauts completely encircle the earth in less than two hours, and the rest of us can get jet flights to almost any part of the earth in twelve hours, we have all come to see the earth as small enough and compact enough to be thought of as a spaceship. the atmosphere of the earth is an ideal radiation shield, transparent to light, but very effectively shielding us from the fierce ultra - violet, x - rays, and higher energy radiations of outer space. in this the earth fulfills admirably one of the primary requisites of a well - designed spaceship. during its long prehuman history, the earth has been prepared with a wealth of supplies now required by man, when he has filled the earth and subdued it, to carry him on his long journey through space from now on. over long stretches of its geologic history, the processes which have concentrated ores of iron, copper, uranium, and other vital metals have by now well stocked the earth with them for man ' s requirements. later in its history coal beds and oil fields were laid down slowly over 100 million years to provide vast reserves of fossilized fuels for man ' s utilization, primarily in the twentieth century and after. it is as though some hidden designer had been at work for the last billion years or so specifically preparing the earth to become the spaceship for this creature who is now rapidly filling the earth and subduing it to his own uses. there are several fundamental requirements for a satisfactory spaceship. first it must have an adequate source of energy which will last throughout the trip. next it must have an adequate food supply or means of producing food for the crew throughout the journey. the air and water reserves in the ship must be kept pure and adequate for all needs. wastes must be reprocessed or disposed of in ways which will not contaminate the ship. and, finally, the crew must not he allowed to increase in numbers, and it must remain unified throughout the journey. divisions into warring rival subcrews or interpersonal conflicts between crew members would be catastrophic in a spaceship on an extended voyage. energy and water all these elements of a spaceship economy face us in a particularly acute form as we move into the last third of this century. consider first the basic requirements for energy and water. these are interrelated, and the key to


voyage. energy and water all these elements of a spaceship economy face us in a particularly acute form as we move into the last third of this century. consider first the basic requirements for energy and water. these are interrelated, and the key to both is nuclear energy. as we consider the vast requirements which face us in the immediate future, it seems remarkably providential that man should have stumbled on nuclear energy and the possibility of its controlled utilization less than thirty years ago. although, spurred by the terrible threat of hitler ' s nazi germany, it was first developed destructively, its discovery has come barely in time to make our continued occupancy of our spaceship possible. until only a dozen years ago, man was exclusively dependent on chemical energy ( with the minor exception of hydroelectric power ) derived from the burning of fossilized fuels, such as coal, oil, and natural gas, with the oxygen of the atmosphere. this form of energy is exceedingly rare, even esoteric, in the universe as a whole. there are very few spots other than the earth in the entire universe where the necessary ingredients for such energy can be found. nuclear energy, on the other hand, is extremely common and universally present throughout all creation. our sun is a natural hydrogen bomb in process of continuous explosion and so are the other so - called " main sequence " stars. our galaxy, the milky way, contains some hundred billion such stars, and all the other galaxies are equally thickly populated with them. cod has made more hydrogen bombs than he has anything else. there is nothing more common or more natural and universal in all creation. in the fullness of time it was inevitable that man in the fulfillment of the promise made at his creation would come to exercise dominion over this universal element of nature as well. to us and to our generation the lot has fallen to experience the fulfillment of the purpose asserted for man when he began to inhabit this planet thirtyfive thousand years ago ; namely, that he should in the fullness of time multiply and fill the whole earth. it is a startling thought. most discussions of nuclear energy today seem to miss completely this natural character of it. instead it is discussed as though it were a purely something introduced into the scheme of things by human technical ingenuity but not intended to he contained in the world as god prepared it for moreover, such discussions tend to concentrate almost exclusively on aspects as though its only role in human affairs were that of placing upon man the terrible burden of our arsenals of nuclear weapons. both of these


by cameron chai scientists at the brookhaven national laboratory have discovered the nanostructure of a new carbon form that could explain its behavior as a high - absorbent sponge when it receives electric charge. the material recently developed at the university of texas, austin, could be integrated into “ supercapacitor ” devices for high capacity energy storage while maintaining other properties including quick recharge time, rapid release of energy, and long lifetime cycles of 10, 000 charge / discharge cycles. dong su and eric stach use a powerful electron microscope to analyze samples of activated graphene at brookhaven ’ s center for functional nanomaterials. says stach : “ the cfn provides access to scientists around the world to solve cutting - edge problems in nanoscience and nanotechnology. this work is exactly what this facility was established to do. ” according to eric stach, brookhaven materials scientist, this makes it suited to store electrical energy needing rapid energy release in electric cars or to regularize power derived from alternate sources like wind and solar power. stach has also co - authored the research paper released recently in science. the supercapacitors resemble batteries due to their capability to store energy. batteries store a lot of energy through chemical reactions and release it over long periods. but supercapacitors store charge in ion form on the electrodes ’ surface like static electricity without depending on chemical reactions. charging the electrodes make the ions separate or polarize allowing the charge to get stored at the junction of the electrodes and electrolyte. electrode pores enhance the surface area where the electrolyte can travel and communicate. this enhances the quantity of energy being stored. the limited charge in the capacitors allows them to be applied in mobile electronic systems, which need limited energy and can operate over long periods. the team used potassium hydroxide to remodel chemically adapted graphene platelets by creating a more porous form of carbon that needed to be characterized at the nanoscale. investigations revealed that the material ' s three - dimensional nanostructure comprised a network of curved, nano - thick walls that formed nano pores measuring 1 to 5nm wide. stach said that along with computational studies they are trying to comprehend the formation of this three - dimensional network to customize the pore sizes to be most advantageous for particular applications including capacitive storage, catalysis, and fuel cells. the team carried out its research at the lab ' s center for functional nanomaterials,


mtf. charge - coupled device : one family of electronic image sensors that output an analog signal. in a digital camera, this analog signal is converted to digital by a separate component. complementary metal – oxide – semiconductor : one family of electronic image sensors that output a digital signal light source or beam whose rays are parallel. a point - wise light source positioned at a lens focal distance provides a collimated beam. a very far point - wise light source, such as a star other than the sun, can also be considered as a collimated beam. the number of colors that can be coded as digital values. a color channel coded on 8 bits can represent 256 different values. a two - dimensional array of colored filters placed on top of a sensor that allow the color of the input light to be recorded. each photosite outputs a value that depicts the light in a subset of the visible spectrum. the most - used color filter array is the bayer array. characteristic of a reflection or transmission material that does not change the spectrum ( though the color ) of the illuminant. process that transforms the color values of the captured scene into digital rgb values displayed on an output device ( screen, printer ). by extension, also designates the process that transforms raw sensor values into displayed rgb values. numerical values defined by dxo labs researchers that represent the numbers of colors that a sensor can distinguish, up to noise. read more non - uniformity of color rendering in the field : an object may not have the same color all across the image field ( see vignetting ). coordinate system representing the visible colors, under a given illuminant. the l * coordinate represents the luminance, while a * and b * represent color ( respectively the green - magenta axis and the blue - yellow axis ). the lab color space was designed to be perceptually uniform, meaning that a same distance between two colors should be perceived as the same difference whatever those colors are. numerical value characterizing the radiation spectrum of a perfect black body. high color temperature leads to a bluish light, low color temperature leads to a reddish light. csf is a functional description of the human visual system threshold sensitivity to the contrast ( i. e. peak - to - peak luminance difference ) of sine wave patterns of a range of spatial frequencies. the contrast sensitivity function ( csf ) is dependent on the viewing conditions, i. e. viewing distance, size of the displayed image and luminance viewing conditions. statistical


scientist n. person. - one who contributes to a body of knowledge called science. scientists contribute to science by using the scientific method, a system of collecting and interpreting data, of which a fundamental aspect is extreme skepticism. ' scientist ' is the word used to describe anyone who contributes to science, professional or merely an amateur. their data is scrutinized by the scientific community, which is composed of other such scientists, to ensure the veracity of the scientist ' s data, the validity of the scientist ' s interpretation, as well as his or her faithfulness to the scientific method. scientists can be either professional or amateur, but amateur scientists are more commonly called nerds and less commonly geeks ( " geek " is more often used to describe someone who is highly proficient with computers ). the word can be used to describe an occupation : " my father was a scientist before the war. " it can also be used as an ideal : " a scientist does not use such a poor technique. " scientists are considered to have dry personalities, because their skepticism is part of their basic nature. most people find such skepticism and extreme rationalism irritating. examples of scientists include : richard p. feynman, albert einstein, niels bohr, archimedes, leonardo da vinci, galileo galilee, charles darwin, francis crick, and his partner james watson.


1 : 21 ). today many scientists reject scripture as a legitimate source of truth and attempt to find entirely “ natural ” explanations for the origin of the universe. they go so far as to say you can ’ t be a scientist if your explanations of our origins depend upon actions of a supernatural being. biologists who are under the sway of evolutionary theory and physicists who believe in billions of years since the origin of the universe generally avoid references to a creator. when they or the media mention god, it ’ s often only as ridicule. for example, the use of the term “ god particle ” when referring to the search for the higgs boson in elementary particle physics is a thinly - veiled attempt to mock the belief in a supernatural creator. interestingly, most scientists dislike the term “ god particle ” because they don ’ t want their research tainted by such an association. the higgs boson, or the “ god particle ” one of the most active large research projects today is the search for an extremely small but energetic particle that is thought to be the key to understanding how mass appeared shortly after the big bang. the higgs boson is a hypothetical elementary particle that has not been observed but, if found, would dramatically advance the 70 - year development of a model of elementary particle interaction. its existence was predicted along with other particles by the so - called standard model. the standard model describes how leptons, quarks, gauge bosons, and the higgs particle fit together and explains how the higgs mechanism takes place, which in turn explains why elementary particles exhibit mass. the discovery of the higgs boson would finally validate the standard model, since it ’ s the only elementary particle predicted by it that hasn ’ t yet been observed. 4 experiments to find the higgs boson are currently being performed using the large hadron collider ( lhc ) at the european organization for nuclear research ( cern ) in switzerland, shown in figure 1. the lhc is expected to be able to answer the question of whether or not the higgs boson actually exists. one possible signature from a simulated proton - proton collision that would demonstrate the higgs boson ’ s existence is shown in figure 2. the higgs boson is believed to decay almost immediately after such a collision into two jets of hadrons ( composite particles made of subatomic elementary particles held together by strong nuclear forces ) and two electrons, visible in figure 2 as lines. in december 2011, two experiments at the


to decay almost immediately after such a collision into two jets of hadrons ( composite particles made of subatomic elementary particles held together by strong nuclear forces ) and two electrons, visible in figure 2 as lines. in december 2011, two experiments at the lhc independently reported that their data hint that the higgs particle probably exists with a mass of about 133 proton masses. the range of mass for the higgs particle is now thought to have been narrowed considerably to between approximately 122 and 138 protons. it is expected that the lhc will have a definite answer by the end of 2012. 5 why scientists dislike the term “ god particle ” the higgs boson doesn ’ t have any specific religious connotations, but it may help unlock processes that occurred at the time of creation. “ calling it the ‘ god particle ’ is completely inappropriate, ” said oliver buchmueller, from the german research team of “ higgs hunters ” at cern. “ it ’ s not doing justice to the higgs [ boson ] and what we think its role in the universe is. it has nothing to do with god. ” 6 scientists hope to discover the invisible higgs field because the theory of its existence is foundational to the proponents of the big bang, the most typically accepted explanation for the origin of mass and space. those who embrace the idea that the universe came into existence through rapid expansion during conditions of extreme density and heat, that planets and life resulted from the big bang, and that matter obtained mass because of a cosmological collision anticipate the discovery of this “ god particle. ” in the 1960s, british scientist peter higgs first proposed the existence of the new physics field, now known as the higgs field, as an explanation for differences between strong and weak fields in physics. the proposal developed into the idea that in the higgs field, interaction between the electromagnetic field and the weak field resulted in matter taking on mass. the nickname “ god particle ” describes the agent that supposedly gave mass to the most basic building block of the universe. “ without it, or something like it, particles would just have remained whizzing around the universe at the speed of light. … hearing it called the ‘ god particle ’ makes me angry. it confuses people about what we are trying to do here at cern ” said pippa wells, a researcher with cern ’ s atlas team. 7 a spokesman for cern, james gillies, agrees with wells : “ of course it has nothing to do with god


we are trying to do here at cern ” said pippa wells, a researcher with cern ’ s atlas team. 7 a spokesman for cern, james gillies, agrees with wells : “ of course it has nothing to do with god whatsoever …. but i can understand why people go that way because the higgs [ boson ] is so important to our understanding of nature. ” 8 according to people who have investigated the subject, the term “ god particle ” originated with a 1993 book by u. s. nobel prize winner leon lederman about the history of particle physics, the god particle : if the universe is the answer, what is the question? 9 yet others who recognize how significant the current research on the higgs boson is continue to use religious themes for it. lisa randall, a theoretical particle physicist and cosmologist at harvard university, recently entitled her latest book knocking on heaven ’ s door. 10 she wasn ’ t thinking about the god of the bible, however, but about natural laws that cause particles to be organized and exhibit mass. she believes, for example, that the higgs field associated with higgs particles causes space to function like a fluid causing particles which move through it to exhibit mass. and, yet, neither randall nor any other scientist can explain where such natural laws originated. her physics is based upon a pantheistic view of the universe, at best. it ’ s legitimate to try and understand how mass, space, and time originated, but not if the processes we use to explain their origin don ’ t involve the creator. the search for the “ god particle ” is an attempt to understand the big bang theory more fully. the big bang says that the universe began as an infinitesimal point and expanded outward, creating space and mass billions of years ago. although this idea may seem consistent with the description of creation in genesis 1 : 1, it is thought to have happened billions of years ago, while the bible says it happened in one 24 - hour day only a few thousand years ago. the theory is also presented as a natural event that didn ’ t require god ’ s involvement. several years ago, carl sagan declared to me through correspondence his full confidence in the big bang theory and its billions of years, but he admitted to one major problem. he couldn ’ t understand where the laws of nature came from. he realized that his view of origins depended upon the laws of nature being present first. yet he had no explanation for their origin because he didn ’ t believe in god


war projects act ( or wpa ) a scheme of the federal arts project, a program which helped artists from 1935 to 1943 by commissioning works of art across america. example : diego rivera ' s man at the crossroads was completed for the federal arts project in rockefeller center, 1933 a collective term for pottery and ceramic objects. colors often associated with fire and sun, which suggest warmth. these are colors which contain red and yellow and appear on one side of the color wheel opposite the cool colors. in weaving, the vertical threads attached to the top and bottom of a loom, through which the weft is woven. a thin, translucent layer of pigment, usually watercolor or india ink. often it is the background of a picture, prepared using watery paint applied quickly using large, sweeping brush strokes. example : helen frankenthaler ' s bay side, 1967 a flat metal or rubber disk placed beneath a bolt head or nut which helps to secure the bolt and distribute its pressure, lessen friction, or prevent leakage. this term is used in two contradictory ways. in its most common use : a piece mold made from a model ( usually of clay or wax ) when the model must be broken apart ( wasted ) in removing it from the mold. the other use : a mold from which only one cast can be taken, because the mold must be broken apart and discarded in order to release the cast. this is how lost - wax casting is accomplished, for instance. the use of this term is highly problematic then, unless the user immediately explains the meaning intended. the application of gold leaf to a surface of gesso ( or whiting ) which may have been coated with bole, and this covered with a water and glue. the gold is then burnished. this is a better technique than oil ( mordant ) gilding, when the surface is a gessoed one, although it is more difficult. any paint that uses water as a medium. paintings done with this medium are known as watercolors. when made opaque with white, watercolor is generally called gouache or bodycolor. tempera is another exception. in the making of paper, a translucent design impressed on it when still moist by a metal pattern, and visible when the paper is held before light. in digital imaging, bits altered within an image to create a pattern which indicates proof of ownership ; so that unauthorized use of a watermarked image can then be traced. soluble in water ; capable of being dissolved in water, especially if a wetting


in digital imaging, bits altered within an image to create a pattern which indicates proof of ownership ; so that unauthorized use of a watermarked image can then be traced. soluble in water ; capable of being dissolved in water, especially if a wetting agent is added, like detergents and soaps. any of various natural, oily or greasy heat - sensitive substances, the most common being beeswax. these consist of hydrocarbons or esters of fatty acids that are insoluble in water but soluble in most organic solvents. may also refer to a solid, plastic or liquid substance, such as ozocerite or paraffin, a petroleum by product, used in coating papers, in crayons, and other products. both natural and synthetic waxes are used in painting as a binder, and as an important ingredient in candles and polishes. they are also important materials used for casting and modeling, generally over an armature. lost wax casting, modeling in wax. or a figure made of wax, especially a life - size wax effigy of a famous person. also, the plural form, used with either a singular or plural verb, refers to an exhibition of wax figures in a museum. the interlacing of yarn or thread to make cloth. in printing, a rotary press that prints on a long roll of paper. in sculpture, the retention of a supporting membrane of material between fingers or other thin extremities, especially in stone sculpture. a piece of material, such as wood or metal, tapered at one edge and thick at the opposite end, used for tightening, securing, levering, or splitting, as when driven into wood along its grain, or when driven into the interlocking corners of wooden stretchers to produce tension on canvas support. these last are also called keys. a technique in which clay is thoroughly kneaded and cut before use in modeling or pottery, to make it plastic and remove air pockets. the threads or strands of yarn that are woven over and under the warp threads to make a weaving. a less commonly used equivalent term is woof. the process of joining metals by fusing them together under direct, intense heat. a commonly used source of heat for welding is an oxyacetylene torch. a metal rod may be applied to the joint which melts into any gaps and strengthens the bond. paper with a coating of silicon carbide, used as an abrasive ; a type of sandpaper. its


##cetylene torch. a metal rod may be applied to the joint which melts into any gaps and strengthens the bond. paper with a coating of silicon carbide, used as an abrasive ; a type of sandpaper. its common name derives from the fact that it can be used wet or dry, as suitable with the materials abraded and the surface finish required. a substance that reduces the surface tension of a liquid, causing the liquid to spread across or penetrate more easily the surface of a solid, making anything that is water - soluble more quickly solved. detergents and soaps generally accomplish this with water. ground and dried chalk used in plate cleaning and in the preparation of gesso. a usually pliable metallic strand made in many lengths and diameters ( gauges ), sometimes clad or coated with insulation, as are electrical wires. a group of wire strands twisted or braided together as a functional unit is called cable. a print similar to a woodcut, in that it is made by cutting a design into a block of wood. however unlike a woodcut, the artist cuts the design on the end grain of hardwood rather than the side grain of soft wood. the print ' s design can therefore be more intricate than the typical woodcut. a print made by cutting a design in side - grain of a block of wood. the ink is transferred from the raised surfaces to paper. example : katsushika kokusai ' s thirty - six view of mount fuji, c. 1823 - 1829 the threads or strands of yarn that are woven over and under the warp threads to make a weaving. the more common contemporary term is weft. the description for a point of view set in the bottom of the picture place, as if a worm were looking at a scene. example : andrea mantegna, st. james led to martyrdom, c. 1455 an iron which is forged - - formed by heating in a furnace and hammering, bending, etc. and welded - - joining two pieces of metal by applying heat, sometimes with pressure, and sometimes with an additional melted metal. it contains less than. 3 % carbon and 1 - 2 % slag. cast iron, on the other hand, is a more brittle, nonmalleable alloy of iron and carbon, which is shaped by from pouring it molten into a mold.


- used books - kobo ereading - staff picks - gifts & gift cards - sell books - stores & events special offers see all more at powell ' s recently viewed clear list six not so easy pieces : lectures on symmetry, relativity, and space - timeby richard feynman synopses & reviews no twentieth - century american scientist is better known to a wider spectrum of people than richard p. feynman ( 19181988 ) — physicist, teacher, author, and cultural icon. his autobiographies and biographies have been read and enjoyed by millions of readers around the world, while his wit and eccentricities have made him the subject of tv specials and even a theatrical film. the spectacular reception of the book and audio versions of feynmans six easy pieces ( published in 1995 ) resulted in a worldwide clamor for more feynman! more feynman! ” the outcome is these six additional lectures, drawn from the celebrated three - volume lectures on physics. though slightly more challenging than the first six, these lectures are more focused, delving into the most revolutionary discovery in twentieth - century physics : einsteins theory of relativity. no single breakthrough in twentieth - century physics ( with the possible exception of quantum mechanics ) changed our view of the world more than that of einsteins discovery of relativity. the notions that the flow of time is not a constant, that the mass of an object depends on its velocity, and that the speed of light is a constant no matter what the motion of the observer, at first seemed shocking to scientists and laymen alike. but, as feynman shows so clearly and so entertainingly in the lectures chosen for this volume, these crazy notions are no mere dry principles of physics, but are things of beauty and elegance. no one — not even einstein himself — explained these difficult, anti - intuitive concepts more clearly, or with more verve and gusto, than richard feynman. book news annotation : six " easy " pieces were published in 1995. now the publisher has dipped back into feynman ' s three - volume lectures on physics to present these somewhat less accessible lectures. while the previous six - piece collection tackled various subjects, this volume deals only with einstein ' s theory of relativity. suitable for students and determined lay readers who want to learn from the master teacher, renowned not only for his scientific contributions, but for his wit, and the immediacy and clarity of his explanations. annotation c. book news, inc., portland, or


determined lay readers who want to learn from the master teacher, renowned not only for his scientific contributions, but for his wit, and the immediacy and clarity of his explanations. annotation c. book news, inc., portland, or ( booknews. com ) the spectacular reception of the book and audio versions of feynmans six easy pieces ( published in 1995 ) resulted in a worldwide clamor for more feynman! more feynman! ” the outcome is these six additional lectures, drawn from the celebrated three - volume lectures on physics. though slightly more challenging than the first six, these lectures are more focused, delving into the most revolutionary discovery in twentieth - century physics : einsteins theory of relativity. " in these lectures, everything you ' ve ever heard about feynman ' s wit and genius comes through ". — john horgan, author of the end of science. " want to really understand why time slows, mass increases and length contracts as something approaches light speed, why space has just got to be curved and why it is not only impossible to predict the future, but actually there is no fortune teller who can even tell us the present? '... sure this is hard stuff — the cerebral equivalent of high - impact aerobics... but there is no better explanation for the scientifically literate layman... just do it ". — the washington post book world table of contents vectors — symmetry in physical laws — the special theory of relativity — relativistic energy and momentum — space - time — curved space. what our readers are saying other books you might like


| physical science | | transformation of energy 6c6. 00 | | process of science | | collecting data 1. 3 ac | content standard : physical science content topic : transformation of energy concept : electricity can be harmful. content objective : 6c6. 00 to understand the importance of observing safety rules in the use of electricity instructional objectives : the learner will : tn component of science : process of science benchmark : the reading and interpretation of measuring instruments are necessary in determining length, volume, weight, elapsed time, rates, and temperature. 1. 3c safety features should be observed in all areas of data collection. benchmark : safety procedures are introduced prior to and practiced during all data collection. heat is produced by electricity. if too much current is flowing through a wire, the wire may become so hot that a fire starts. this can be caused if too many appliances are plugged into the outlet and used at the same time. circuit breakers can prevent this. a current can also overheat if there is a short circuit. a short circuit occurs when two wires in a cord accidentally touch. most of the time cords are covered by insulation. the insulation keeps the wires from touching. if the insulation becomes damaged, this creates an area of low resistance and if a large current goes through this area, there will be rapid over - heating and possibly result in a fire. repair damaged insulation immediately. water and electricity are always a dangerous combination. water conducts electricity. you should never use electric appliances or touch sources of electricity such as light bulbs, sockets, or outlets while in contact with water. any wire connected to a voltage is called a live wire. you should never touch a live wire. if you do, your body will become part of a circuit. a large current will flow through you and into the ground. live wires often fall to the ground because of storms or accidents. never touch a live wire. call the power company immediately. 1. ask someone from your local power company to bring a meter and demonstrate how to read it. 2. ask your local power company for information about electric safety and what to do in an electrical emergency. 3. divide the class into groups of four. write and perform your own commercial about electrical safety. 4. materials : one dry cell battery ( 6 volts ), a small light bulb and socket, 1 large cork, 2 straight pins, a piece of thin metal foil ( remove the paper backing of a gum wrapper ) 3 cm long copper wire ( approximately 80 cm ),


century dictionary and cyclopedia - n. the character of being indefinite, undefined, unlimited, or not precise and certain. - n. the characteristic of being indefinite. gnu webster ' s 1913 - n. the quality of being indefinite. - n. the quality of being vague and poorly defined “ the only reply that it is possible is that the indefiniteness is the result of design. ” “ it is extremely difficult to distinguish in observation between vagueness of the illusion due to feebleness in the after - image depending on faint illumination, dark - colored discs or lack of the desirable difference in luminosity between the sectors ( cf. p. 171 ) and the indefiniteness which is due to broad transition - bands existing between the ( relatively ) pure - color bands. ” “ they illustrate that indefiniteness which is characteristic of greek mythology, a theology with no central authority, no link on historic time, liable from the first to an unobserved transformation. ” “ indefiniteness ' and ' general imbecility ' of what we had to offer - - all so unworthy a _ bostonian _ audience - - we commenced, and with many interruptions of applause, concluded. ” “ indefiniteness " of the tiger leave and after first claiming " the pga tour has not been significantly impacted in a negative way " provided this more realistic assessment. ” “ its euphony and indefiniteness were a charm tohim. ” “ its euphony and indefiniteness were a charm to him. ” “ he argues that " doctrinal indefiniteness can be a reasonable expression of epistemic modesty, and that even doctrinal entanglement can be justified when it is the only way of preserving, in the sociocultural environment available, a reflectively stable orientation. ” “ instead, he put it off with vagueness and indefiniteness and inquired after the family, particularly after mrs. morse and ruth. ” “ i find indefiniteness a bit harder to get my head around. ” ‘ indefiniteness ’ hasn ' t been added to any lists yet. looking for tweets for indefiniteness.


issue date : july 27, 2009 making graphene in a flash no time to make graphene via conventional routes? then make it " in a flash. " northwestern university scientists have just demonstrated that graphite oxide can be converted instantly to graphene via photothermal deoxygenation by exposing the material to a pulse of light from an ordinary camera flash ( j. am. chem. soc., doi : 10. 1021 / ja902348k ). because of its low cost and wide availability, graphite oxide is a promising precursor for making graphene - based materials, which are being studied for use in polymer composites and electronics. the oxide is typically treated at high temperature or with potent reducing agents such as hydrazine to yield graphene. now, laura j. cote, rodolfo cruz - silva, and jiaxing huang of northwestern have shown in a video that the flash method is an instantaneous, chemical - free way to transform graphite oxide, an electrical insulator, into graphene, a conductor, at room temperature. the team has also shown that by applying masking and photolithography methods, the flash technique can be used to fabricate complex patterns, a key step in developing electronic components. - chemical & engineering news - issn 0009 - 2347 - copyright © american chemical society


protection against lag switches in the form of voltage detectors, which detect a change in voltage when the switch is flipped. some manufacturers have taken counter measures to bypass or trick this detector. this can also be achieved by simply unplugging the ethernet cord going to the console, causing a disruption in the player ' s internet connection. other methods, called a software or wireless lag switch, involve using a computer program. in this method, the cheater runs an application on a computer connected to the same network as the console. the application hogs the network bandwidth, disrupting the communication between the console and its server. however, one cannot do this for an unlimited amount of time. usually, having no internet connection for 30 seconds will cause one ' s character / player to be kicked from the game due to inactivity / no internet connection. in the peer - to - peer gaming model, lagging refers to a player with a faster connection flooding an opponent ( s ) using a basic denial - of - service attack outside the game structure. look - ahead cheating is a method of cheating within a peer - to - peer multiplayer gaming architecture where the cheating client gains an unfair advantage by delaying his actions to see what other players do before announcing its own action. a client can cheat using this method by acting as if it is suffering from high latency ; the outgoing packet is forged by attaching a time - stamp that is prior to the actual moment the packet is sent, thereby fooling other clients into thinking that the action was sent at the correct time, but was delayed in arrival. a partial solution is the lockstep protocol. maphack is a generic term that refers to a method or third - party program that enables a user to see more of a level than intended by the developer. a maphacker is a user that deliberately executes such a method or program in the context of a relevant game, whilst maphacking is the act of such. a common aspect of real - time strategy games is the player ' s partial limitation or complete inability to see beyond the visibility range of individual game objects that are under their ownership ( typically units and structures ), this concept is controlled by a mechanism known as the fog of war. maphacking usually enables the user to bypass this mechanism, either by removing it entirely and / or by rendering objects through the fog that would not normally be visible. in multiplayer modes, this allows for a distinct advantage against the other players that are subject to the intended settings. the advantage gained can


level or stat requirements to equip the item. circumventing these level requirements would then be further cheating. most games allow other participants to observe the game as it is played from a variety of perspectives ; depending on the game, perspectives allow an observer a map overview or attach a " camera " to the movement of a specific player. in doing so, the observer can communicate with an accomplice using a secondary communication methodology ( in - game private message, third party communication, or even off - line ) to inform friendly players of traps or the position of opponents. an observer can be an active player, using a separate computer, connection and account. some systems prevent inactive players from observing the game if they are on the same ip address as an active player, on the grounds that they are probably in close physical proximity ; when all players from a single ip address are no longer active participants, they are all allowed to observe. however, this restriction can be easily evaded if there are multiple ip addresses available at one location ( a common feature of broadband subscriptions ), or if the observer installs remote desktop software on their computer, thus enabling their computer screen to be viewed by select other players in real time. secret alliances similar to ghosting in some respects, if two or more players to engage secret, co - operative play while all are active ( especially in mmorpgs ) it is considered cheating in many games, in particular when players engage in secondary communication. using remote desktop software to observe the screens of secret " allies " while one is playing could confer considerable tactical and / or strategic advantages for all players in the " alliance ", and would be considered cheating. in some rts games, this is made difficult by replacing all player names with " unknown ". this makes players unable to know who they are private messaging. starcraft 2 and warcraft 3 are examples of this anti - secret alliance setting. in games like super smash bros. brawl, sometimes when not using team battle 2 or more characters would try to attack one character and have one character win. most of the time these people would be the same character with the same or different costume. stacking involves altering game settings or team lineups to give one or more teams an unfair advantage over others. one example includes arranging a team composed of skilled or known players against a team with members of lesser skill. although this may be a valid and accepted practice in real - life sports, in online games stacking upsets less - skilled players who feel that they aren


sent from a client should be accepted by a server if it breaks the game rules or the basic mechanics of the game, and that no information should be sent to a client unless it is " need - to - know. " for example, a server with no rule enforcement or data integrity checking will synchronize all of the clients with all of the information about all of the other clients. the server will be very fast, but any wallhack program will reveal where all the players in the game are, what team they are on, and what state they ' re in — health, weapon, ammo etc. at the same time, altered and erroneous data from a client will allow a player to break the game rules, manipulate the server, and even manipulate other clients. game code modification many cheats are implemented by modifying game software, despite eulas which forbid modification. while game software distributed in binary - only versions makes it harder to modify code, reverse engineering is possible. also game data files can be edited separately from the main program and thereby circumvent protections implemented in software. wallhacks and maphacks often function by modifying the software. other cheats analyze or change the game state in memory, such as some aimbots and programs that give infinite ammo or health ( often called trainers ). additionally, software with legitimate use outside of gaming can fulfill the role of a cheat when used inside a game. examples include program accelerators and an auto clicker. system software modification rather than modifying the game code ( which the game itself or a 3rd - party protection system may detect ), some cheats modify underlying system components. an example of this is graphics driver modifications that ignore depth checking and draw all objects on the screen — a primitive wallhack. system or driver modification is harder to detect, as there are a large number of system drivers that differ from user to user. packet interception, tampering & manipulation the security of game software can be circumvented by intercepting and / or manipulating data in real - time while in transit from the client to the server or vice versa. interception can be passive ( see ghosting and esp ) or result in active manipulation ( see wallhacks ) ; either methodology can be performed on the client machine itself or via an external communication proxy ; some aimbots incorporate this methodology. anti - cheating methods and limitations there are many facets of cheating in online games which make the creation of a system to stop cheating very difficult ; however, game developers


client machine itself or via an external communication proxy ; some aimbots incorporate this methodology. anti - cheating methods and limitations there are many facets of cheating in online games which make the creation of a system to stop cheating very difficult ; however, game developers and third party software developers have created or are developing technologies that attempt to prevent cheating. anti - cheat software is commonly used in popular games such as team fortress 2, quake, or world of warcraft. a few examples of anti - cheat software are dmw anticheat, gameguard, punkbuster, vac, protectenviron, shoxguard, cleandod, xray, xtrap, hackshield, fairfight, warden or battleye. exploits of bugs are usually resolved / removed via a patch to the game ; however, not all companies force the patches / updates on users, leaving the actual resolution to individual users. client datafile checksums one common method used to prevent cheating is for a checksum ( such as an md5 sum ) to be calculated against each game datafile on the client computer, and for these checksums to be reported to the server before the client can join the game. when a cheater has modified a datafile to give them an advantage over others, the changes will affect the calculated checksum and may result in the client being automatically denied from joining the server if an unknown checksum is detected. someone who is attempting to cheat and who has downloaded a cheating package from the internet may possibly be automatically banned by game servers, if certain well - known hacked datafile checksums are detected by the server during the connection attempt. once a datafile has been checked, it is held in a " file open " state, so that other software on the multitasking system can not rename or copy over a file after the check has been done, and the current game session is in progress. when the game session ends, the files are closed until the next check - in. this works only on systems that enforce such file locks, however. the kernel or libraries of a system could be modified to disable the file locking, without making this apparent to the program. non - standard datafile storage some games work to prevent hacking by storing game data in a custom - built private database format that strips file names and directory structures, but does not otherwise encrypt the file data. this is commonly visible as two files, one containing file data for all objects, textures, sounds,


forming ability. according to wickner, these experiments argue for an in - register parallel β - sheet structure for the prion fibrils, as scrambling would disrupt the correspondence of amino acids in any other β - strand structure. susan lindquist ( whitehead institute, cambridge, usa ) described elegant sup35 cross - linking experiments that revealed that sup35 monomers in amyloid fibrils are arranged in a ' head - to - head, tail - to - tail ' fashion. amyloid is the general name given to the fibrillar protein aggregate formed by prions and some other proteins. such amyloid structure also implies parallel in - register arrangement of β strands in the prion fibrils. lindquist proposed that these considerations, combined with the β - helical nanotube structure of the sup35 fibrils, suggested a new structural model for prions, which may have broad implications for amyloids. prions come in different variants or ' strains '. in mammals, whose prions are infectious agents causing a set of fatal neurodegenerative diseases, different prion strains are defined by specific incubation times, distribution of vacuolar lesions in the brain, and patterns of accumulation. for yeast [ psi + ], strain differences can be revealed by differences in phenotypic manifestation ( nonsense suppression caused by the aggregation - dependent inactivation of the translation termination factor sup35 ) and stability of maintenance. generally, ' weak ' [ psi + ] manifest less stable inheritance and worse phenotypic manifestation than ' strong ' [ psi + ]. from her results, lindquist suggested a structural basis for [ psi + ] variants : in ' weak ' [ psi + ] variants a longer sup35 fragment is incorporated into the amyloid core. the physical basis of prion strain differences was also considered by jonathan weissman ( university of california, san francisco, usa ). his group had previously shown that sup35 fibrils obtained in vitro at 4°c and 37°c transform yeast cells to strong [ psi + ] variants, and weak [ psi + ], respectively. atomic force microscopy revealed two distinctions between the 4°c ( sc4 ) and 37°c ( sc37 ) fibrils. sc4 fibrils polymerized more slowly than sc37, but were more fragile and therefore smaller and more numerous, which ensured their efficient polymerization. correlated with the strong phenotype of sc4 fibrils is the fact that


the university of technology in sydney recently unveiled a new type of graphene nano paper that is ten times stronger than a sheet of steel. composed of processed and pressed graphite, the material is as thin as a sheet of paper yet incredible durable — this strength and thinness gives it remarkable applications in many industries, and it is completely recyclable to boot. photo by wikimedia commons to make graphene paper, raw graphite is milled and purified using a chemical bath, which reshapes its structure, allowing it to be pressed into thin sheets. these graphene sheets boast excellent thermal, electrical and mechanical properties – including excellent hardness and flexibility. graphene offers many advantages over steel – it ’ s two times as hard, six times lighter and ten times higher in tensile strength. this translates into a next - gen material that could immensely benefit the automotive and aviation industries. lighter planes and cars use less fuel and create less pollution. companies such as boeing have already begun using carbon - based materials, so graphene paper would be the next logical step. raw graphite is a relatively plentiful material in australia, where the research is being conducted. the researchers welcome the industry boost that increased demand for raw graphite for graphene paper would provide. lead photo © lisa aliosio


| cookies : by using this website you agree that we can place google analytics cookies on your device for performance monitoring. | optical metamaterials - bending the laws of physics if you have a question about this talk, please contact tim wilkinson. tea is served from 6pm metamaterials are artificial materials with properties that do not exist normally in nature. advances in nanoscale fabrication allow for the realization of optical metamaterials which allow us to manipulate light in ways that were orignially not thought to be possible. these materials are composed of subwavelength electromagnetic structures place very close to one another. due to mutual coupling between the individual structures, they present properties to incident electromagnetic radiation ( such as light ) that are different from those associated with the material from which the structures are comprised of. in this talk we use periodic arrays of multiwalled carbon nanotubes as subwavelength structures to produce optical metamaterials that exhibit artificial dielectric properties and band gaps within the optical regime. this talk is part of the iet cambridge network - lectures series. this talk is included in these lists : note that ex - directory lists are not shown. other listsgraduate seminars religion, conflict and its aftermath talks metabolism other talkspsychometric application of bifactor modelling for multidimensional mental health phenotype : a population based genotype ‐ trait association study serre weights and de rham cohomology of shimura curves annual general meeting an introduction to origins of the afro comb exhibition the immunology of a successful pregnancy under the bonnet of the ferrari of the virus world - norovirus replication and immune evasion


into the exhausted space, and its presence could then be detected spectroscopically by raising the mercury and compressing the gases into the vacuum - tube. in order to avoid any possible contamination of the apparatus with helium, freshly distilled mercury and entirely new glass apparatus were used. before introducing the emanation into a, the absence of helium was confirmed experimentally. at intervals after the introduction of the emanation the mercury was raised, and the gases in the outer tube spectroscopically examined. after 24 hours no trace of the helium yellow line was seen ; after 2 days the helium yellow was faintly visible ; after 4 days the helium yellow and green lines were bright ; and after 6 days all the stronger lines of the helium spectrum were observed. the absence of the neon spectrum shows that the helium present was not due to a leakage of air into the apparatus. there is, however, one possible source of error in this experiment. the helium may not be due to the α particles themselves, but may have diffused from the emanation through the thin walls of the glass tube. in order to test this point the emanation was completely pumped out of a, and after some hours a quantity of helium, about 10 times the previous volume of the emanation, was compressed into the same tube a. the outer tube t and the vacuum - tube were removed and a fresh apparatus substituted. observations to detect helium in the tube t were made at intervals, in the same way as before, but no trace of the helium spectrum was observed over a period of eight days. the helium in the tube a was then pumped out and a fresh supply of emanation substituted. results similar to the first experiment were observed. the helium yellow and green lines showed brightly after four days. these experiments thus show conclusively that the helium could not have diffused through the glass walls, but must have been derived from the α particles which were fired through them. in other words, the experiments give a decisive proof that the α particle after losing its charge is an atom of helium. we have seen that in the experiments above described helium was not observed in the outer tube in sufficient quantity to show the characteristic yellow line until two days had elapsed. now the equilibrium amount of emanation from 100 milligrams of radium should produce helium at the rate of about. 03 c. mm. per day. the amount produced in one day, if present in the outer tube, should produce a bright spectrum of helium under the


of helium was then spectroscopically looked for in the usual way. using this method, it was found possible to detect the presence of helium in the lead which had been exposed for only four hours to the α rays from the emanation. after an exposure of 24 hours the helium yellow and green lines came out brightly. these experiments were repeated several times with similar results. a number of blank experiments were made, using samples of the lead - foil which had not been exposed to the α rays, but in no case was any helium detected. in a similar way, the presence of helium was detected in a cylinder of tinfoil exposed for a few hours over the emanation - tube. these experiments show that the helium does not escape at once from the lead, but there is on the average a period of retardation of several hours and possible longer. the detection of helium in the lead and tin foil, as well as in the glass, removes a possible objection that the helium might have been in some way present in the glass initially, and was liberated as a consequence of its bombardment by the α particles. the use of such thin glass tubes containing emanation affords a simple and convenient method of examining the effect on substances of an intense α radiation quite independently of the radioactive material contained in the tube. we can conclude with certainty from these experiments that the α particle after losing its charge is a helium atom. other evidence indicates that the charge is twice the unit charge carried by the hydrogen atom set free in the electrolysis of water. university of manchester, nov. 13, 1908 proc. roy. soc. a. lxxxi, pp. 141 - 173 ( 1908 ). proc. roy. soc. a. lxxxi. p. 280 ( 1908 ). the α particles fired at a very oblique angle to the tube would be stopped in the glass. the fraction stopped in this way would be small under the experimental conditions. that the air was completely displaced was shown by the absence of neon in the final spectrum.


inorganic chemistry is a subdiscipline of chemistry involving the scientific study of the properties and chemical reactions of all chemical elements and chemical compounds other than the vast number of organic compounds ( compounds containing at least one carbon - hydrogen covalent bond ). there are a number of subdivisions of inorganic chemistry such as the five subdivisions of the american chemical society ' s division of inorganic chemistry ( asc dic ), namely organometallic chemistry, bioinorganic chemistry, solid - state and materials chemistry, coordination chemistry and nanoscience. inorganic chemistry is closely related to other disciplines such as materials science, earth science, mineralogy, geology and crystallography. distinctions between inorganic and organic chemistry the distinction or boundary between inorganic chemistry and organic chemistry is not very well defined. in general, the above definition of inorganic chemistry seemingly excludes carbon compounds but it does not exclude elemental carbon itself. hence, carbon oxides, carbon sulfides, cyanides and cyanates, metallic carbides and carbonates are included as inorganic compounds. as another example of the ill - defined distinction between inorganic and organic chemistry, oxalic acid ( h2c204 ) is commonly considered to be an organic compound even though it does not contain a carbon - hydrogen bond. classification of inorganic compounds inorganic chemistry encompasses a very complicated variety of substances which the distinguished american chemist, f. albert cotton ( 1930 − 2007 ), grouped into these four classes : the chemical elements : these have a variety of structure and properties and include : - atomic gases such as argon ( ar ) and krypton ( kr ), as well as molecular gases such as hydrogen ( h2 ) and oxygen ( o2 ). - molecular solids such as the phosphorus allotrope ( p4 ), the sulfur allotrope ( s8 ), and the carbon allotrope ( c60 ). - network solids such as diamonds and graphite. - metals, either solid such as copper ( cu ) and tungsten ( w ) or liquid such as mercury ( hg ) and gallium ( ga ). - simple ionic compounds such as sodium chloride ( nacl ), which are soluble in water or other polar solvents. - ionic oxides that are insoluble in water, such as zirconium oxide ( zro2 ) and mixed oxides such as the mineral " spinel " ( mgal2o4 ), the mineral " diopside " ( camg ( sio3 ) 2 )


, such as zirconium oxide ( zro2 ) and mixed oxides such as the mineral " spinel " ( mgal2o4 ), the mineral " diopside " ( camg ( sio3 ) 2 ) and various silicates. - other binary halides, carbides, arsenides, nitrides and similar materials. a few examples are silver chloride ( agcl ), silicon carbide ( sic ), gallium arsenide ( gaas ), and boron nitride ( bn ), some of which could also be considered to be network solids. - compounds containing polyatomic ions ( also called " complex ions " ) such as the silicon hexafluoride anion [ sif6 ] 2 –, the cobalt hexammine cation [ co ( nh3 ) 6 ] 3 + and the ferricyanide anion [ fe ( cn ) 6 ] 3 –. molecular compounds : these may be solids, liquids or gases and include : - simple binary compounds such as phosphorus trifluoride ( pf3 ), sulfur dioxide ( so2 ) and osmium tetroxide ( oso4 ). - organometallic compounds that characteristically have metal−to−carbon bonds such as nickel carbonyl ( ni ( co ) 4 ) and tetra - benzyl - zirconium ( zr ( ch2c6h5 ) 4 ). - complex metal - containing compounds. inorganic polymers and superconductors : these include various inorganic polymers and superconductors. one example is the polymer named yttrium barium copper oxide ( yba2cu3o7 ) which is commonly abbreviated as ybco. it is a crystalline chemical compound and was the first material to achieve superconductivity above the boiling point of liquid nitrogen ( 77 k ). typical inorganic chemical reactions there is no universally accepted list of the typical, important inorganic reactions. although there are numerous available sources ( books, journal and internet websites ) that include such lists, they all differ to some extent from each other. the inorganic reaction types listed and explained below were drawn from many of the available sources : synthesis reaction : ( also referred to as combination or composition reaction ) this is a reaction in which two or more reactants combine to form a single product, where each reactant is a chemical element or compound and the reaction product consist of the two reactants. examples include : • sodium + chlor


composition reaction ) this is a reaction in which two or more reactants combine to form a single product, where each reactant is a chemical element or compound and the reaction product consist of the two reactants. examples include : • sodium + chlorine ⇒ sodium chloride 2na + cl2 ⇒ 2nacl • carbon dioxide + water ⇒ carbonic acid co2 + h2o ⇒ h2co3 • hydrogen + sulfur ⇒ hydrogen sulfide h2 + s ⇒ h2s decomposition reaction : ( may be thermal, electrolytic or catalytic decomposition reaction ) this is a reaction in which a chemical compound is separated into elements or simpler compounds. it is often defined as being the opposite of a synthesis reaction. examples include : • hydrogen peroxide ⇒ water + oxygen ( hydrogen peroxide spontaneously decomposes into water and oxygen ) 2h2o2 ⇒ 2h20 + o2 • calcium carbonate + heat ⇒ calcium oxide + carbon dioxide ( heated calcium carbonate decomposes into calcium oxide and gaseous carbon dioxide ) caco3 + heat ⇒ cao + co2 single displacement reaction : ( also referred to as substitution or single replacement reaction ) this is a reaction characterized by one element being displaced from a compound by another element. examples include : • copper + hydrochloric acid ⇒ cupric chloride + hydrogen cu + 2hcl ⇒ cucl2 + h2 • zinc + cupric sulfate ⇒ copper + zinc sulfate zn + cuso4 ⇒ cu + znso4 metathesis reaction : ( also referred to as exchange or double displacement or double replacement reaction ) this is a reaction in which two compounds exchange bonds or ions to form new, different compounds. examples include : • sodium sulfate + barium chloride ⇒ barium sulfate + sodium chloride na2so4 + bacl2 ⇒ baso4 + 2nacl • silver nitrate + hydrochloric acid ⇒ nitric acid + silver chloride agno3 + hcl ⇒ hno3 + agcl precipitation reaction : ( a specific type of metathesis referred to as aqueous metathesis ) this is a reaction that occurs when two inorganic salt solutions, as in the example below, react to form a solution containing a soluble product and another product that is insoluble and precipitates out of the solution : • calcium chloride + silver nitrate ⇒ calcium nitrate + silver chloride ( insoluble silver chloride precipitates out of the aqueous cacl2 ( aq ) + 2agno3 ( aq ) ⇒


terms of its constituent chemical elements and can thus determine the chemical formula of a compound. modern laboratory equipment and techniques can provide many more details for characterizing chemical compounds. some of the more commonly used modern techniques are : - chromatography : a process for separating mixtures of chemicals into their component constituents. - x - ray diffraction or x - ray crystallography : a technique that determines the three - dimensional arrangement of atoms within a molecule. - spectrometry or qualitative spectroscopy : a technique for the identification of substances through the electromagnetic spectrum emitted from or absorbed by them. - voltammetry : an electrochemical method for studying a chemical substance by measuring the electrical potential and / or electric current in an electrochemical cell containing the substance. - inorganic chemistry : a study guide, from the website of the university of waterloo, canada - christopher g. morris ( editor ) ( 1992 ), academic press dictionary of science and technology, 1st edition, academic press, isbn 0 - 12 - 200400 - 0. - welcome to the acs dic webpage!, from the website of the american chemical society division of inorganic chemistry. - note : for example, carbon monoxide ( co ), carbon dioxide ( co2 ), carbon disulfide ( cs2 ), sodium cyanide ( nacn ), potassium cyanate ( kocn ), silicon carbide ( sic ) and calcium carbonate ( caco3 ) - f. albert cotton, geoffrey wilkinson and paul l. gaus ( 1995 ), basic inorganic chemistry, 3rd edition, john wiley, isbn 0 - 471 - 50532 - 3. first published in 1976 with professor f. albert cotton of texas a & m university as the main author. - note : allotropes are molecules having different molecular structures. this differs from isotopes which are elements having different atomic structures ( i. e., the same number of protons but different numbers of neutrons in the atomic nucleus ). the carbon allotrope ( c60 ) is also known as buckminsterfullerine. - note : network solids are chemical compounds with the atoms being bonded by covalent bonds in a continuous network. thus, there are no individual molecules in a network solid and the entire solid may be considered to be a macromolecule. diamond is an example of a network solid with a continuous network of carbon atoms. another example is graphite, which consists of continuous two dimensional layers of carbon atoms covalently bonded within


entire solid may be considered to be a macromolecule. diamond is an example of a network solid with a continuous network of carbon atoms. another example is graphite, which consists of continuous two dimensional layers of carbon atoms covalently bonded within each layer and with other bond types holding the layers together. - yttrium barium copper oxide – ybco, from the wiki of the chemistry department at imperial college, london, england. - p. a. cox ( 2004 ), inorganic chemistry, 2nd edition, taylor & francis, isbn 1 - 85996 - 289 - 0. - types of equations, from the website of the virginia polytechnic institute and state university. - types of inorganic chemical reactions : four general categories, dr. anne marie helmenstine on the website of about. com : chemistry. - types of chemical reactions : list of common reactions and examples, dr. anne marie helmenstine on the website of about. com : chemistry. - note : an arrhenius acid is defined as dissociating in aqueous solution to form hydrogen ions and arrhenius bases, which form hydroxide ions. there are a number of other theories and definitions of acids, namely brønsted – lowry acid – base theory, lewis acids and bases, usanovitch definition, and various others.


a discovery reported in the august 5 issue of science could speed the design of materials that approach the hardness of diamond yet remain supple enough to be worked like metal. in a massive computer simulation involving 128 computer processors and nearly 19 million atoms, materials scientist izabela szlufarska of the university of wisconsin - madison and colleagues at university of southern california demonstrated the precise atomic mechanisms that explain why " nanostructured " ceramic materials - some of the hardest substances known - also exhibit unusual pliability. unlike other exceptionally hard materials, these advanced ceramics tend to bend rather than break, meaning they could be shaped into extremely long - lasting yet lightweight parts for everything from automobile engines and high - speed machining tools to medical implants in the body. but they are also notoriously difficult to engineer, because as their name implies they possess a grain structure that falls into the nano - size range of molecules and atoms. " how to optimize their design is an open question, " says szlufarska, who is also a professor of engineering physics. " people have used a trial and error approach to make these materials harder. but there is still much to be understood as to why they are harder. " simulations can help to answer this by providing a level of detail unavailable to experiments. using atomic - scale simulations, the team observed for the first time how atoms moved and interacted as a super - hard ceramic deformed under stress. the advance has not only provided unprecedented insight into the properties of these materials, but also a tool that researchers can use to systematically nano - engineer them. " this study is just the first step, " says szlufarska. " the goal is to design the strongest material possible. " the particular nanostructured ceramic szlufarska focuses on, called nanocrystalline silicon carbide, is also exceptionally resistant to high temperature and radiation, which has nasa eyeing it as a coating for the space shuttle. another important application is micro - electro mechanical systems ( mems ), tiny machines that are currently made of silicon. " todays mems cant have two surfaces rubbing against one another because the silicon is brittle and tends to break, " says szlufarska. " if we could instead make mems out of silicon carbide, the sky would be the limit in terms of applications. " normal ceramics, like clays, become brittle when fired. but when ceramic is made from particles spanning mere atoms in diameter, the material exhibits dramatically


mems out of silicon carbide, the sky would be the limit in terms of applications. " normal ceramics, like clays, become brittle when fired. but when ceramic is made from particles spanning mere atoms in diameter, the material exhibits dramatically improved ductility after bonding at high temperature and pressure. this unusual combination of strength and suppleness is derived from the materials two - phase nature. in nanocrystalline silicon carbide, says szlufarska, highly ordered, crystalline grains are surrounded by a more disordered, or amorphous, matrix of grain boundaries - much like tiny stones cemented by a semi - fluid mortar. and the volume of grain boundaries exceeds that in other nanostructured materials such as metals. to understand, at the atomic scale, how nanocrystalline silicon carbide deforms under force, the team performed a simulation in which they pressed a tiny, virtual probe, called an indenter, into the materials surface and watched how the atoms moved in response. initially, the grains deformed and then sprang back as a unit, an illustration of the materials hardness. " at this point, the grains all moved together because the grain boundaries held them together like glue, " says szlufarska. but as the probe pressed deeper and exerted greater pressure, the researchers witnessed a surprising shift in the materials response. at a specific indentation depth, the grain boundaries began to yield, allowing individual grains to rotate and glide independently under the probes force. " because the grain boundaries are flowing, the material is more ductile than normal ceramic would be, " says szlufarska. " and the grain boundaries initially take part of the deformation, so in essence they protect the grains from breaking. " in contrast, nano - structured metals go through no such phase ; instead their grains take the brunt of the force, immediately developing defects, like tiny cracks, when the material begins to yield. " once defects occur in the system, the system is just weaker and its going to break, " says szlufarska. this crossover in response - from cooperative grain movement and hardness, to individual movement and ductility - is unique to nano - structured ceramics, she says. the researchers next want to learn how to control the crossover point so as to engineer greater hardness into nano - crystalline silicon carbide without compromising pliability. for example, they could vary the volume of the grain boundaries or the size of the grains. impurities


to learn how to control the crossover point so as to engineer greater hardness into nano - crystalline silicon carbide without compromising pliability. for example, they could vary the volume of the grain boundaries or the size of the grains. impurities, or dopants, might also be added to the grain boundaries to make the material stronger. key to it all is the enormous computing power that allows scientists to simulate the materials atomic details. " the experiments and devices have become smaller and smaller, while the simulations have grown larger and larger, " says szlufarska. " this is a unique time when the leading edge of materials design is exactly at the same length scale where fully atomic simulations are possible. " izabela szlufarska | source : eurekalert! further information : www. wisc. edu more articles from materials sciences : new filtration material could make petroleum refining cheaper, more efficient 24. 05. 2013 | national institute of standards and technology ( nist ) innovation could bring flexible solar cells, transistors, displays 23. 05. 2013 | purdue university this morning at 05 : 45 cest, the earth trembled beneath the okhotsk sea in the pacific northwest. the quake, with a magnitude of 8. 2, took place at an exceptional depth of 605 kilometers. because of the great depth of the earthquake a tsunami is not expected and there should also be no major damage due to shaking. professor frederik tilmann of the gfz german research centre for geosciences : " the epicenter is exceptionally deep, far below the earth ' s crust in the mantle. such strong... the ring nebula ' s distinctive shape makes it a popular illustration for astronomy books. but new observations by nasa ' s hubble space telescope of the glowing gas shroud around an old, dying, sun - like star reveal a new twist. " the nebula is not like a bagel, but rather, it ' s like a jelly doughnut, because it ' s filled with material in the middle, " said c. robert o ' dell of vanderbilt university in nashville, tenn. he leads a research team that used hubble and several ground - based telescopes to obtain the best view yet of... new indicator molecules visualise the activation of auto - aggressive t cells in the body as never before biological processes are generally based on events at the molecular and cellular level. to understand what happens in the course of infections, diseases or normal bodily functions, scientists would


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