to use all functions of this page, please activate cookies in your browser. with an accout for my. chemeurope. com you can always see everything at a glance – and you can configure your own website and individual newsletter. - my watch list - my saved searches - my saved topics - my newsletter the reaction rate or rate of reaction for a reactant or product in a particular reaction is intuitively defined as how fast a reaction takes place. for example, the oxidation of iron under the atmosphere is a slow reaction which can take many years, but the combustion of butane in a fire is a reaction that takes place in fractions of a second. chemical kinetics is the part of physical chemistry that studies reaction rates. the concepts of chemical kinetics are applied in many disciplines, such as chemical engineering, enzymology and environmental engineering. formal definition of reaction rate consider a typical chemical reaction : the lowercase letters ( a, b, p, and q ) represent stoichiometric coefficients, while the capital letters represent the reactants ( a and b ) and the products ( p and q ). according to iupac ' s gold book definition the reaction rate v ( also r or r ) for a chemical reaction occurring in a closed system under constant - volume conditions, without a build - up of reaction intermediates, is defined as : the iupac recommends that the unit of time should always be the second. in such a case the rate of reaction differs from the rate of increase of concentration of a product p by a constant factor ( the reciprocal of its stoichiometric number ) and for a reactant a by minus the reciprocal of the stoichiometric number. reaction rate usually has the units of mol dm - 3 s - 1. it is important to bear in mind that the previous definition is only valid for a single reaction, in a closed system of constant volume. this most usually implicit assumption must be stated explicitly, otherwise the definition is incorrect : if water is added to a pot containing salty water, the concentration of salt decreases, although there is no chemical reaction. for any system in general the full mass balance must be taken into account : in - out + generation = accumulation when applied to the simple case stated previously this equation reduces to : for a single reaction in a closed system of varying volume the so called rate of conversion can be is used, in order to avoid handling concentrations. it is defined as the derivative of the extent of reaction with respect to time. is


the process paradigm " a paradigm is the fundamental lens through which we view our environment. the paradigm that governs our thinking about a given system is the theory that determines the invariant features that shape the system and defines how to succeed within the system. usually a paradigm is so ingrained, so rooted in our familiar sense of the way things are, that we hold it unconsciously, without either choice or deliberation. " a paradigm is a framework of perceiving, thinking and acting. it is a cognitive structure composed of aggregated concepts, values, beliefs and assumptions that organizes how we perceive, how we think and how we act — by, consciously or unconsciously, supporting rule - governed behavior. cultural - social institutions utilize and promote paradigms in endeavors as diverse as science & technology, economics & commerce, business & multi - national corporations, organized religion & personal spirituality, family & marriage, government & citizenship. each of these examples use a framework of unwritten rules to direct behavior and establish social expectations. the word " paradigm " was described by a cnn survey as one of the most overused words of 2004. this is because of the tremendous rush of cultural, social and technological change, and emergent transformations taking place. we have so little language to adequately describe, or become self - aware of the cultural forces which are driving us. if our assumptions, beliefs and values are unconscious, then a paradigm will function like superstition : a mind - set, or way of perceiving, that anchors a rigid view of the world, and thus fixates rigidity in our thinking and behavior. it can create an illusion / delusion that there is only one " right way " to perceive, think or act. however, if we are conscious of our concepts, assumptions, beliefs and values, then we can apply a paradigm as a mental tool : a set of rules or mental models that we use so long as they adequately express truth, value, and integrity. they are rules, models, frames of perception and mind - sets that are to be surrendered when they no longer serve us. a mental model which serves us well at one developmental stage can be an obstacle in another stage if no revision, updating, reframing or cognitive maintenace occurs. some of the best examples of paradigms are found in science, where a paradigm is used as a framework of ideas applied to a particular topic for explanation, prediction, problem - solving or methodology. in the constantly evolving fields of science everyone understands that these rules of explanation and


examples of paradigms are found in science, where a paradigm is used as a framework of ideas applied to a particular topic for explanation, prediction, problem - solving or methodology. in the constantly evolving fields of science everyone understands that these rules of explanation and method are transient and subject to ongoing revision and improvement. joel barker has defined paradigm this way : " a paradigm is a set of rules and regulations ( written or unwritten ) that does two things : ( 1 ) it establishes or defines boundaries ; and ( 2 ) it tells you how to behave inside the boundaries in order to be successful. " joel barker, paradigms : the business of discovering the future ( 1992 ), p 32. barker further points to the following terms, which he arranged on a spectrum from " challengeable to unchallengeable. " he believes these are subsets of the concept of paradigm : " theory, model, methodology, principles, standards, protocol, routines, assumptions, conventions, patterns, habits, common sense, conventional wisdom, mind - set, values, frames of reference, tradition, customs, prejudices, ideology, inhibitions, superstitions, rituals, compulsions, addictions, doctrine, dogma " ( ibid., pp 35 - 36 ). the idea behind a paradigm shift is that the rules of a " game " change as a new mental model becomes available. with a new mental model comes a consequent, often dramatic, transformation of perception, thinking and action. a three - part process the cognitive design process is offered as a mental model for planning and evaluation of the instructional design process. the heuristic device has three parts : - performance environment principles - design element principles - cognitive learning principles each part involves analysis leading to problem - identification, and instructional decisions leading to solution design — strategy, tactics, and methods. here is a graphic portrayal of the model : this model provides an integrated framing of instructional development requirements : - define the goal & content of instruction, - design the instruction & learning process — appropriate to audience, resources and environment, - develop the needed media elements to optimize communication and learner interaction, and - deliver instruction effectively using appropriate technology infrastructure and environmental controls. design of performance improvement environments performance problems are not always " training " problems. - many problems are due to lack of timely information and communication. - other performance problems are due to motivational issues. - there may be hidden organizational dynamics or history which establish structural barriers or impediments to, or sabbatoge of,


the spin of a molecule ( orange ) changes and deforms the nanotube ( black ) mounted between two electrodes ( gold ). ( figure : c. grupe / kit ) carbon nanotubes and magnetic molecules are considered building blocks of future nanoelectronic systems. their electric and mechanical properties play an important role. researchers of karlsruhe institute of technology and french colleagues from grenoble and strasbourg have now found a way to combine both components on the atomic level and to build a quantum mechanical system with novel properties. it is reported now in the print version of nature nanotechnology journal ( doi : 10. 1038 / nnano. 2012. 258 ). in their experiment the researchers used a carbon nanotube that was mounted between two metal electrodes, spanned a distance of about 1 µm, and could vibrate mechanically. then, they applied an organic molecule with a magnetic spin due to an incorporated metal atom. this spin was oriented in an external magnetic field. “ in this setup, we demonstrated that the vibrations of the tube are influenced directly when the spin flips parallel or antiparallel to the magnetic field, ” explains mario ruben, head of the working group at kit. when the spin changes, the resulting recoil is transferred to the carbon nanotube and the latter starts to vibrate. vibration changes the atomic distances of the tube and, hence, its conductance that is used as a measure of motion. the strong interaction between a magnetic spin and mechanical vibration opens up interesting applications apart from determining the states of motion of the carbon nanotube. it is proposed to determine the masses of individual molecules and to measure magnetic forces within the nano - regime. use as a quantum bit in a quantum computer might also be feasible. according to the supplementary information published in the same issue of nature nanotechnology such interactions are of high importance in the quantum world, i. e. in the range of discrete energies and tunnel effects, for the future use of nanoscopic effects in macroscopic applications. combination of spin, vibration, and rotation on the nanoscale in particular may result in entirely new applications and technologies.


the weird world of quantum mechanics describes the strange, often contradictory, behaviour of small inanimate objects such as atoms. researchers have now started looking for ways to detect quantum properties in more complex and larger entities, possibly even living organisms. a german - spanish research group, split between the max planck institute for quantum optics in garching and the institute of photonic sciences ( icfo ), is using the principles of an iconic quantum mechanics thought experiment - schrodinger ' s superpositioned cat – to test for quantum properties in objects composed of as many as one billion atoms, possibly including the flu virus. new research published today, thursday 11 march, in new journal of physics ( co - owned by the institute of physics and german physical society ), describes the construction of an experiment to test for superposition states in these larger objects. quantum optics is a field well - rehearsed in the process of detecting quantum properties in single atoms and some small molecules but the scale that these researchers wish to work at is unprecedented. when physicists try to fathom exactly how the tiniest constituents of matter and energy behave, confusing patterns of their ability to do two things at once ( referred to as being in a superposition state ), and of their ' spooky ' connection ( referred to as entanglement ) to their physically distant sub - atomic brethren, emerge. it is the ability of these tiny objects to do two things at once that oriol romero - isart and his co - workers are preparing to probe. with this new technique, the researchers suggest that viruses are one type of object that could be probed. albeit speculatively, the researchers hope that their technique might offer a route to experimentally address questions such as the role of life and consciousness in quantum mechanics. in order to test for superposition states, the experiment involves finely tuning lasers to capture larger objects such as viruses in an ' optical cavity ' ( a very tiny space ), another laser to slow the object down ( and put it into what quantum mechanics call a ' ground state ' ) and then adding a photon ( the basic element of light ) in a specific quantum state to the laser to provoke it into a superposition. the researchers say, " we hope that this system, apart from providing new quantum technology, will allow us to test quantum mechanics at larger scales, by preparing macroscopic superpositions of objects at the nano and micro scale. this could then enable us to use more complex microorganisms, and thus test the quantum superposition principle


of the stable or “ noble ” gases that rarely react with other elements. a dozen years later, two soviet scientists, gennady gutsev and alexander boldyrev, showed that a larger class of molecules with a metal atom at the center surrounded by halogen atoms, similar to platinum hexafluoride, possesses electron affinities larger than that of chlorine. they termed these molecules “ superhalogens. ” “ for example, you could take a sodium atom and a chlorine atom to make a sodium chloride molecule and then attach a second chlorine atom. that compound would then want another electron because of the extra chlorine, ” jena said. “ all of a sudden, the electron affinity, which is the characteristic we ’ re after, becomes almost a factor of two larger than that of the chlorine atom. it becomes a superhalogen. ” superhalogens have similar, improved properties as halogens, jena said. jena, together with anil kandalam, ph. d., assistant professor at mcneese state university, theorized that they could push the electron affinity of a cluster or a molecule even higher, by using superhalogens as building blocks, instead of halogens, around a metal atom. the theoretical model was tested through experimental studies led by gerd f. gantefor, ph. d., at the university of konstanz. they termed these species with unusually large electron affinities as “ hyperhalogens. ” “ we used gold as the metal and surrounded it with two boron - dioxide superhalogens and got a hyperhalogen with an even greater electron affinity, ” jena said. the team ’ s synergistic approach involving theory and experiment produced a gold - borate hyperhalogen with an electron affinity of 5. 7 ev. the team now is testing a hyperhalogen constructed with four boron - dioxide superhalogens and have reached an electron affinity of 7 ev, with a goal of building a hyperhalogen with 10 ev. these new hyperhalogens may lead to additional discoveries of novel chemicals, jena said. the theoretical investigations for the project were conducted by jena and graduate student mary willis at vcu, along with kandalam. the experimental work was conducted by gantefor and graduate student matthias gotz at the university of konstanz. the work was supported in part by the federal defense threat reduction agency and the department of energy. the institute of


name : sam j. i am tring to find out a good diamagnetic material for magnetic levatation. i know that bismuth is the best diamagnetic material. but with respect to carbon - graphite. i have seen experaments using this and it works well. i was wondering if you could use just carbon or just graphite, and what would work better. is it a combination of carbon and graphite that works best or is one just a filler? would using just carbon work better, or just graphite i also heard that the more dense the carbon is, the better it works. i just tring to find the best combination to use that will levatate the best. i plan on getting the matrial in tile form so i can cover a desk and levatate a magnet over actually, graphite is carbon. carbon - graphite is carbon in graphite form. carbon atoms tend to join together in one of three patterns, depending on how hard they are pressed together. under very high pressure, carbon will form a crystal pattern people like to call diamond. under more mediocre conditions, carbon tends to form coal. if presed together very lightly, often when deposited near the surface, carbon tends to form a pattern called graphite is a pattern of sheets laid on top of sheets. the carbon atoms form a sheet of hexagons, each carbon joined to three other carbons. since carbon can bond with four atoms, the fourth connection extends up or down from the sheet for each atom. this joins to an atom in an adjacent sheet. graphite has very weak bonds and a great deal of open space. this is what makes it such a wonderful substance to put inside a pencil. when you write with a pencil, you deposit carbon atoms on the paper. dr. ken mellendorf the only way you will be able to actually get the magnet to levitate indefinitely is to use a superconductor as the diamagnet. otherwise the eddy currents induced in the diamagnet will fade due to electrocal resistance, allowing the magnet to approach ever closer. richard e. barrans jr., ph. d. pg research foundation, darien, illinois click here to return to the physics archives update : june 2012


| red - orange metallic luster native copper ( ~ 4 cm in size ) | name, symbol, number | | copper, cu, 29 | | element category | | transition metal | | group, period, block | | 11, 4, d | | standard atomic weight | | 63. 546 ( 3 ) | | electron configuration | | [ ar ] 3d 4s 2, 8, 18, 1 | naming | | after cyprus, principal mining place in roman era ( cyprium ) | | discovery | | middle easterns ( 9000 bc ) | | density ( near r. t. ) | | 8. 96 g · cm | | liquid density at m. p. | | 8. 02 g · cm | | melting point | | 1357. 77 k, 1084. 62 °c, 1984. 32 °f | | boiling point | | 2835 k, 2562 °c, 4643 °f | | heat of fusion | | 13. 26 kj · mol | | heat of vaporization | | 300. 4 kj · mol | | molar heat capacity | | 24. 440 j · mol · k | | oxidation states | | + 1, + 2, + 3, + 4 ( mildly basic oxide ) | electronegativity | | 1. 90 ( pauling scale ) | | 1st : 745. 5 kj · mol | | 2nd : 1957. 9 kj · mol | | 3rd : 3555 kj · mol | | atomic radius | | 128 pm | | covalent radius | | 132±4 pm | | van der waals radius | | 140 pm | | crystal structure | | face - centered cubic | | electrical resistivity | | ( 20 °c ) 16. 78 nω · m | | thermal conductivity | | 401 w · m · k | | thermal expansion | | ( 25 °c ) 16. 5 µm · m · k | | speed of sound ( thin rod ) | | ( r. t. ) ( annealed ) | young ' s modulus | | 110 – 128 gpa | | shear modulus | | 48 gpa | | bulk modulus | | 140 gpa | | vickers hardness | | 369 mpa | | brinell hardness | | 874 mpa | | cas registry number | | 7440 - 50 - 8 | | most stable isotopes | | main article : isotopes of copper | copper is a chemical element with


copper are lacking a covalent character and are relatively weak. this explains the low hardness and high ductility of single crystals of copper. at the macroscopic scale, introduction of extended defects to the crystal lattice, such as grain boundaries, hinders flow of the material under applied stress thereby increasing its hardness. for this reason, copper is usually supplied in a fine - grained polycrystalline form, which has greater strength than monocrystalline forms. the softness of copper partly explains its high electrical conductivity ( 59. 6×10 s / m ) and thus also high thermal conductivity, which are the second highest among pure metals at room temperature. this is because the resistivity to electron transport in metals at room temperature mostly originates from scattering of electrons on thermal vibrations of the lattice, which are relatively weak for a soft metal. the maximum permissible current density of copper in open air is approximately 3. 1×10 a / m of cross - sectional area, above which it begins to heat excessively. as with other metals, if copper is placed against another metal, galvanic corrosion will occur. together with caesium and gold ( both yellow ), and osmium ( bluish ), copper is one of only four elemental metals with a natural color other than gray or silver. pure copper is orange - red and acquires a reddish tarnish when exposed to air. the characteristic color of copper results from the electronic transitions between the filled 3d and half - empty 4s atomic shells – the energy difference between these shells is such that it corresponds to orange light. the same mechanism accounts for the yellow color of gold and caesium. copper forms a rich variety of compounds with oxidation states + 1 and + 2, which are often called cuprous and cupric, respectively. it does not react with water, but it slowly reacts with atmospheric oxygen forming a layer of brown - black copper oxide. in contrast to the oxidation of iron by wet air, this oxide layer stops the further, bulk corrosion. a green layer of verdigris ( copper carbonate ) can often be seen on old copper constructions, such as the statue of liberty, the largest copper statue in the world built using repousse and chasing. copper tarnishes when exposed to hydrogen sulfides and other sulfides, which react with it to form various copper sulfides on the surface. oxygen - containing ammonia solutions give water - soluble complexes with copper, as do oxygen and hydrochloric acid to form copper chlorides and acid


silver and gold alloys and carat solders used in the jewelry industry, modifying the color, hardness and melting point of the resulting alloys. the alloy of copper and nickel, called cupronickel, is used in low - denomination coins, often for the outer cladding. the us 5 - cent coin called nickel consists of 75 % copper and 25 % nickel and has a homogeneous composition. the 90 % copper / 10 % nickel alloy is remarkable by its resistance to corrosion and is used in various parts being exposed to seawater. alloys of copper with aluminium ( about 7 % ) have a pleasant golden color and are used in decorations. some lead - free solders consist of tin alloyed with a small proportion of copper and other metals. as for other elements, the simplest compounds of copper are binary compounds, i. e. those containing only two elements. the principal ones are the oxides, sulfides and halides. both cuprous and cupric oxides are known. among the numerous copper sulfides, important examples include copper ( i ) sulfide and copper ( ii ) sulfide. copper, like all metals, forms coordination complexes with ligands. in aqueous solution, copper ( ii ) exists as [ cu ( h2o ) 6 ]. this complex exhibits the fastest water exchange rate ( speed of water ligands attaching and detaching ) for any transition metal aquo complex. adding aqueous sodium hydroxide causes the precipitation of light blue solid copper ( ii ) hydroxide. a simplified equation is : many other oxyanions form complexes ; these include copper ( ii ) acetate, copper ( ii ) nitrate, and copper ( ii ) carbonate. copper ( ii ) sulfate forms a blue crystalline pentahydrate, which is the most familiar copper compound in the laboratory. it is used in a fungicide called the bordeaux mixture. polyols, compounds containing more than one alcohol functional group, generally interact with cupric salts. for example, copper salts are used to test for reducing sugars. specifically, using benedict ' s reagent and fehling ' s solution the presence of the sugar is signaled by a color change from blue cu ( ii ) to reddish copper ( i ) oxide. schweizer ' s reagent and related complexes with ethylenediamine and other amines dissolve cellulose. amino acids form very stable chelate complexes with copper ( ii ). many wet - chemical tests for copper ions exist, one involving potassium fe


prevent biofouling, even in extreme conditions and have strong structural and corrosion - resistant properties in marine environments. copper - alloy touch surfaces have natural intrinsic properties to destroy a wide range of microorganisms ( e. g., e. coli o157 : h7, methicillin - resistant staphylococcus aureus ( mrsa ), staphylococcus, clostridium difficile, influenza a virus, adenovirus, and fungi ). some 355 copper alloys were proven to kill more than 99. 9 % of disease - causing bacteria within just two hours when cleaned regularly. the united states environmental protection agency ( epa ) has approved the registrations of these copper alloys as “ antimicrobial materials with public health benefits, " which allows manufacturers to legally make claims as to the positive public health benefits of products made with registered antimicrobial copper alloys. in addition, the epa has approved a long list of antimicrobial copper products made from these alloys, such as bedrails, handrails, over - bed tables, sinks, faucets, door knobs, toilet hardware, computer keyboards, health club equipment, shopping cart handles, etc. ( for a comprehensive list of products, see : antimicrobial copper - alloy touch surfaces # approved products ). copper doorknobs are used by hospitals to reduce the transfer of disease, and legionnaires ' disease is suppressed by copper tubing in plumbing systems. antimicrobial copper alloy products are now being installed in healthcare facilities in the u. k., ireland, japan, korea, france, denmark, and brazil and in the subway transit system in santiago, chile, where copper - zinc alloy handrails will be installed in some 30 stations between 2011 – 2014. copper compounds in liquid form are used as a wood preservative, particularly in treating original portion of structures during restoration of damage due to dry rot. together with zinc, copper wires may be placed over non - conductive roofing materials to discourage the growth of moss. textile fibers use copper to create antimicrobial protective fabrics, as do ceramic glazes, stained glass and musical instruments. electroplating commonly uses copper as a base for other metals such as nickel. copper is one of three metals, along with lead and silver, used in a museum materials testing procedure called the oddy test. in this procedure, copper is used to detect chlorides, oxides, and sulfur compounds.


metals such as nickel. copper is one of three metals, along with lead and silver, used in a museum materials testing procedure called the oddy test. in this procedure, copper is used to detect chlorides, oxides, and sulfur compounds. copper is also commonly found in jewelry, and folklore says that copper bracelets relieve arthritis symptoms, though this has been shown to be incorrect. copper proteins have diverse roles in biological electron transport and oxygen transportation, processes that exploit the easy interconversion of cu ( i ) and cu ( ii ). the biological role for copper commenced with the appearance of oxygen in earth ' s atmosphere. the protein hemocyanin is the oxygen carrier in most mollusks and some arthropods such as the horseshoe crab ( limulus polyphemus ). because hemocyanin is blue, these organisms have blue blood, not the red blood found in organisms that rely on hemoglobin for this purpose. structurally related to hemocyanin are the laccases and tyrosinases. instead of reversibly binding oxygen, these proteins hydroxylate substrates, illustrated by their role in the formation of lacquers. copper is also a component of other proteins associated with the processing of oxygen. in cytochrome c oxidase, which is required for aerobic respiration, copper and iron cooperate in the reduction of oxygen. copper is also found in many superoxide dismutases, proteins that catalyze the decomposition of superoxides, by converting it ( by disproportionation ) to oxygen and hydrogen peroxide : several copper proteins, such as the " blue copper proteins ", do not interact directly with substrates, hence they are not enzymes. these proteins relay electrons by the process called electron transfer. copper is an essential trace element in plants and animals, but not some microorganisms. the human body contains copper at a level of about 1. 4 to 2. 1 mg per kg of body mass. stated differently, the rda for copper in normal healthy adults is quoted as 0. 97 mg / day and as 3. 0 mg / day. copper is absorbed in the gut, then transported to the liver bound to albumin. after processing in the liver, copper is distributed to other tissues in a second phase. copper transport here involves the protein ceruloplasmin, which carries the majority of copper in blood. ceruloplasmin also carries copper that is excreted in milk, and is particularly well


proper rows and columns in the truth tables, a purely automatic procedure, has a crucial resemblance to the " instruction tables " turing proposed. one of the important features of boolean algebra is the way logical operations can be put together to form new ones, and collections of logical operations can be put together to perform arithmetic operations. logical syllogisms can be constructed in terms of operations on zeroes and ones, by arranging for the output of one truth table to feed input to another truth table. for example, it turns out that by putting a not before every and input, and putting another not after its output, it is possible to build an " or " operation. by stringing various sequences of only these two basic operations, " not " and " and, " it is possible to build procedures for adding, subtracting, multiplying, and dividing. logic and arithmetic are thus intimately and simply related. what nobody knew until shannon told us was that the same algebra could describe the behavior of electrically switched circuits. equally important was the way these combinations of logical and arithmetic operations could be used to build a " memory " operation. boolean algebra makes it possible to devise a procedure, or build a device, the " state " of which can store specific information - - either data or operations. if electrical circuitry can perform logical and mathematical operations, and can also store the result of those operations, then electronic digital computers can be designed. until shannon, boolean algebra had been a curious and almost totally forgotten eddy in the mainstream of mathematical thought for almost a century, and was certainly unknown to the more practical - minded world of physics and electrical engineering. and that is where the genius of shannon ' s rediscovery lies, for he was writing a thesis in electrical engineering, not mathematical logic, and the objects of his concern were not the processes of thought but the behavior of large circuits of electrical switches connected together into the kinds of circuits one finds in a telephone system. shannon was interested in the properties of complicated electrical circuits that were built from very simple devices known as relays. a relay is a switch - - a device that opens or closes a circuit, permitting or blocking the flow of electricity - - not unlike an ordinary light switch, except a relay is not switched on or off by a human hand, but by the passage of an electrical current. a relay contains an electromagnet. when a small current flows into the relay, the electromagnet is activated, closing the circuit controlled by the relay until the input


by a human hand, but by the passage of an electrical current. a relay contains an electromagnet. when a small current flows into the relay, the electromagnet is activated, closing the circuit controlled by the relay until the input current is turned off. in other words, the electromagnet is a small electrical circuit that opens and closes another electrical circuit. the circuit of one relay can also control the electromagnet of the next relay, and so on, until you have a complete circuit that is made of nothing but switches, all controlling one another, depending on how they are set at the beginning and how they are altered by new input. each relay and circuit controlled by that relay can be in only one of two states, on or off. this two - state characteristic of switched circuits is what links electricity to logic, for each relay - controlled circuit can be seen as a truth table, where current flows from the output only when specified input conditions are satisfied, and logical operations can be seen as physical devices that emit an output pulse if and only if all of their input switches are on, or off, or some specified combination, in the 1930s, telephone systems were using ever larger and more complicated mazes of circuits controlled by these relays. instead of requiring a human operator to plug the proper jack into the right part of a switchboard, relays could close the circuit when the specified input conditions were reached. using relays, all kinds of useful things could be done in the way of automatic dialing and routing. but the growing complexity of the circuitry was getting to be a problem. it was becoming harder and harder to figure out what these big collections of switches were doing. shannon was looking for a mathematical procedure that was best suited for describing the behavior of relay circuits. his thesis showed how george boole ' s algebra could be used to describe the operations of these complex circuits. and he was not unaware of the implications if the fact that these circuits could now be designed to represent the operations of logic and arithmetic. if logic was the formal system that most closely matched the operations of human reason, and if boole ' s truth tables could embody such a formal system of simulated reasoning, then the use of truth tables as the " instruction tables " turing discussed, and with switching devices like relays to represent the " states " of the machines ( or the cells of the tape ), it would be possible to build electrical circuits that could simulate some of the logical operations of human thought. when the


turing discussed, and with switching devices like relays to represent the " states " of the machines ( or the cells of the tape ), it would be possible to build electrical circuits that could simulate some of the logical operations of human thought. when the digital computer builders got together to plan the future development of the technology, shannon was in the thick of it - - and he didn ' t hesitate to remind his colleagues that what they were building was the first step toward artificial intelligence. but during the ten years immediately following his first breakthrough, shannon turned to a different aspect of this new field. his new employer was bell laboratories, and the electrical or electronic communication of messages was his specialty. at & t, the foremost communication company in the world, was the owner of bell laboratories, so naturally the laboratory was interested in supporting shannon ' s probes into the fundamental nature of communication. shannon was encouraged to pursue his interesting questions such as : when something is communicated, what is delivered from one party to another? when a communication is obscured by noise or encryption, what fails to get across? this was the communication part of the communication and control problem pointed out by wiener. during the war, working at top - secret defense projects for bell laboratories, shannon was involved in cryptological work that brought him into contact with turing. after the war, shannon concentrated on describing the nature of the entity they were communicating and manipulating with all these logical and mathematical circuits. at this point, nobody knew, exactly, what information was. just as he had found the perfect tool for describing relay circuits, after the war shannon wanted to find mathematical tools for precisely defining the invisible but powerful commodity that these new machines were processing. he succeeded in finding the descriptive tools he sought, not in an obscure corner of mathematics, as in the case of boole ' s algebra, but in the fundamental laws governing energy. like turing, shannon put a surprise finishing touch on a project that scientists had worked at for centuries. in this case, the quest was not to understand the nature of symbol systems, but a more pragmatic concern with the nature of energy and its relation to information. although shannon was specifically looking at the laws underlying the communication of messages in man - made systems, and generally interested in the difference between messages and noise, he ended up dealing with the laws governing the flow of energy in the universe. in particular, he discovered the secrets of decoding telephone switching networks, hidden in the work of previous scientists who had discovered certain laws governing heat energy in steam engines. back when the


up dealing with the laws governing the flow of energy in the universe. in particular, he discovered the secrets of decoding telephone switching networks, hidden in the work of previous scientists who had discovered certain laws governing heat energy in steam engines. back when the industrial revolution was getting started, and steam - powered engines were the rage, it became a practical necessity to find out something about the efficiency of these energy - converting devices. in the process, it was discovered that something fundamental to the nature of heat prevents any machine from ever becoming perfectly efficient. the study of the movement of heat in steam engines became the science of thermodynamics, given precise expression in 1850 by rudolf clausius, in his two laws of thermodynamics. the first law of thermodynamics stated that the energy in a closed system is constant. that means that energy cannot be created or destroyed in such systems, but can only be transformed. the second law states, in effect, that part of that unchangeable reservoir of energy becomes a little less stable every time a transformation takes place. when you pour hot water into cold water, you can ' t separate it back into a hot and a cold glass of water again ( without using a lot more energy ). entropy, meaning " transformation, " was the word claudius later proposed for that lost quantity of usable energy. entropy as defined by clausius is not just something that happens to steam engines or to glasses of water. it is a universal tendency that is as true for the energy transactions of the stars in the sky as it is for the tea kettle on the stove. because the universe is presumed to be a closed system, and since clausius demonstrated that the entropy of such systems tends to increase with the passage of time, the gloomy prediction of a distant but inevitable " heat death of the universe " was a disturbing implication of the second law of thermodynamics. " heat death " was what they called it because heat is the most entropic form of energy. but the gloomy news about the end of time wasn ' t the only implication of the entropy concept. when it was discovered that heat is a measure of the average motion of a population of molecules, the notion of entropy became linked to the measure of order or disorder in a system. if this linkage of such disparate ideas as " heat, " " average motion, " and " order of a system " sounds confusing, you have a good idea of how nineteenth - century physicists felt. for a


in a system. if this linkage of such disparate ideas as " heat, " " average motion, " and " order of a system " sounds confusing, you have a good idea of how nineteenth - century physicists felt. for a long time, they thought that heat was some kind of invisible fluid that was transferred from one object to another. when it was discovered that heat is way of characterizing a substance in which the molecules were, on the average, moving around faster than the molecules in a " cold " substance, a new way of looking at systems consisting of large numbers of parts ( molecules, in this case ) came into being. and this new way of looking at the way the parts of systems are arranged led, eventually, to the entropy - information connection. because " average motion " of molecules is a statistical measure, saying something about the amount of heat in a system says something about they way the parts of that system are arranged. think about a container of gas. the system in this case includes everything inside the container and everything outside the container. the gas is considered to be hot if the average energy of the molecules inside the container is higher than the average energy of the molecules outside the container. some of the molecules inside the container might, in fact, be less energetic ( cooler ) than some of the molecules outside the container - - but on the average, the population of molecules inside are more energetic than the population of the molecules outside. there is a certain order to this arrangement - - energetic molecules are more likely to be found inside the container, less energetic molecules are more likely to be found outside. if there were no container, the highly energetic molecules and the less energetic molecules would mix, and there would be no sharp differentiation between the hot parts and the cold parts of the system. a system with high entropy has a low degree of order. a system with low entropy has a higher degree of order. in a steam engine, you have the heat in one place ( the boiler ) and it is dissipated into the cold part ( the condenser ). this is a very orderly ( low entropy ) system in the sense that anyone can reliably predict in which part of the engine the hot molecules are likely to be found. but when all the parts of a steam engine are the same temperature, and the hot and cold molecules are equally likely to be found in the boiler and the condenser ( and hence the entropy is high ), the engine can ' t do any work. another physicist, boltzman


steam engine are the same temperature, and the hot and cold molecules are equally likely to be found in the boiler and the condenser ( and hence the entropy is high ), the engine can ' t do any work. another physicist, boltzmann, showed that entropy is a function of the way the parts of the system are arranged, compared with the number of ways the system can be arranged. for the moment, let ' s forget about molecules and think about decks of cards. there is a large number of ways that fifty - two cards can be arranged. when they come from the factory, every deck of cards is arranged in a definite order, by suit and by value. with a little bit of thought, anybody can predict which card is the fifth from the top of the deck. the predictability and orderliness disappears when the deck is shuffled. an unshuffled deck of cards has a lower degree of entropy because energy went into arranging it in an unlikely manner. less energy is then required to put the deck into a more probable, less orderly, less predictable, more highly entropic state : according to the second law of thermodynamics, all decks of cards in the universe will eventually be shuffled, just as all molecules will have an equal amount of energy. james clerk maxwell, yet another nineteenth - century scientist, proposed a paradox concerning this elusive quality called entropy, which seems to relate such intuitively dissimilar measures as energy, information, order, and predictability. the paradox became infamous among physicists under the name " maxwell ' s demon. " consider a container split by a barrier with an opening small enough to pass only one molecule at a time from one side to another. on one side is a volume of hot gas, in which the average energy of the molecules is higher than the average energy of the molecules in the cold side of the container. according to the second law, the hotter, more active molecules should eventually migrate to the other side of the container, losing energy in collisions with slower moving molecules, until both sides reach the same temperature. what would happen, maxwell asked, if you could place a tiny imp at the molecular gate, a demon who didn ' t contribute energy to the system, but who could open and close the gate between the two sides of the container? now what if the imp decides to let only the occasional slow - moving, colder molecule pass from the hot to the cold side when it randomly approaches the gate? taken far enough, this policy could mean that the hot


the two sides of the container? now what if the imp decides to let only the occasional slow - moving, colder molecule pass from the hot to the cold side when it randomly approaches the gate? taken far enough, this policy could mean that the hot side would get hotter and the cold side would get colder, and entropy would decrease instead of increase without any energy being added to the system! in 1922, a hungarian student of physics by the name of leo szilard ( later to be von neumann ' s colleague in the manhattan project ), then in berlin, finally solved the paradox of maxwell ' s demon by demonstrating that the demon does indeed need to contribute energy to the system, but like a good magician the demon does not expend that energy in its most visible activity - - moving the gate - - but in what it knows about the system. the demon is a part of the system, and it has to do some work in order to differentiate the hot and cold molecules at the proper time to open the gate. simply by obtaining the information about molecules that it needs to know to operate the gate, the demon adds more entropy to the system than it subtracts. although szilard showed implicitly that information and entropy were intimately connected, the explicit details of the relationship between these two qualities, expressed in the form of equations, and the generalization of that relationship to such diverse phenomena as electrical circuits and genetic codes, were not yet known. it was claude shannon who made information into a technical term, and that technical term has since changed the popular meaning of the word. another puzzle related to entropy, and the cryptic partial solution to it proposed in 1945 by another physicist, was a second clue linking it to information. quite simply : if the universe tends toward entropy, how does life, a highly ordered, energy - consuming, antientropic phenomenon, continue to exist? in a universe flowing toward disorder, how on earth did one - celled creatures complicate themselves enough to build a human nervous system? quantum physicist erwin schrodinger pointed out that life defies the cosmic energy tide courtesy of our sun. as long as the sun keeps shining, the earth is not a closed system. photochemical reactions on earth capture a tiny fraction of the sun ' s radiant energy and use it to complicate things. in his famous " what is life? " lecture in 1945, schrodinger remarked that " living organisms eat negative energy. " the relationship between negative energy and information, like boole ' s obscure


and use it to complicate things. in his famous " what is life? " lecture in 1945, schrodinger remarked that " living organisms eat negative energy. " the relationship between negative energy and information, like boole ' s obscure algebra, was just waiting to be found when shannon started to wonder how messages manage to maintain their order in a medium where disorder is often high. the matter of devising a simple code and reliably transmitting it from place to place was very important to british cryptographers, and shannon had done his own work in cryptography. the prediction of the behavior of electrical circuits used to transmit messages made of these codes was another of shannon ' s interests. when he put it all together with a formal examination of how messages can be distinguished from noise, and found that the very equation he sought was a variation of the defining equation for entropy, claude shannon happened upon the fact that the universe plays twenty questions with itself. the formal foundations of information theory were laid down in two papers in 1948, and at their core were fundamental equations that had a definite relationship to boltzmann ' s equations relating entropy to the degree of order in a system. but the general idea behind the equations was simple enough for shannon to suggest a game as a way of understanding the quantitative dimension of coding and communication. the game is a mundane version of " twenty questions. " in the case of the english alphabet, it turns out to be a game of " five questions. " player number one thinks of a letter of the alphabet. player number two tries to guess the letter, using only questions like " is it earlier than l in the alphabetical sequence? " it is a strictly yes - or - no game, in which only one of two possible answers applies at every move. shannon pointed out that it takes a maximum of five questions to locate any of the thirty symbols necessary for making english sentences. if the sequence of yes or no decisions needed to specify the correct letter is converted into a sequence of zeroes and ones or a sequence of on and off impulses, or any other kind of binary symbol, you have a code for communicating the alphabet - - which is, in fact, the basis of the code used for transmitting teletypewriter messages. this game can be visualized as a tree structure, where each letter is the only leaf on a branch that branches off a branch that eventually branches off a trunk. or it can be seen as a garden of forking paths, where each path is a sequence of one -


feet tall, and one is six feet tall, you have quite precise information about that population, which would enable you to pick out individuals by height. but if all you know is that the average height of the population is four feet, eight inches, you wouldn ' t know anything useful about any one of the three particular individuals. whenever a system is represented by an average, some information is necessarily lost, just as two energy states lose a little energy when they are brought into equilibrium. whenever you move from an average measure to a precise measure, you have reduced uncertainty about that population. and that reduction in uncertainty is where the statistical properties that govern the motions of populations of molecules are connected to the statistical properties of a binary code, where entropy meets information. to see how uncertainty can relate to a binary code, think about a game of twenty questions. if the object of the game is to guess a number between one and one hundred, and player one asks if the number is larger than fifty, an answer from player two ( no matter if it is yes or no ) reduces player one ' s uncertainty by one half. before asking the question, player one had one hundred possible choices. after asking that single yes or no question, player one either knows that the number is greater than fifty or that it is less than fifty. one of the things shannon demonstrated in 1948 was that the entropy of a system is represented by the logarithm of possible combinations of states in that system - - which is the same as the number of yes - or - no questions that have to be asked to locate one individual case. entropy, as it was redefined by shannon, is the same as the number of binary decisions necessary to identify a specific sequence of symbols. taken together, those binary decisions, like the answers in the game, constitute a definite amount of information about the system. when it comes to arranging molecules, living organisms seem to have a great deal of information about how to take elementary substances and turn them into complex compounds. somehow, living cells manage to take the hodgepodge of molecules found in their environment and arrange them into the substances necessary for sustaining life of the organism. from a disorderly environment, living creatures somehow create their own internal order. this remarkable property now sounds suspiciously like maxwell ' s demon. the answer, as we now know, is to be found in the way the dna molecule arranges its elements - - doing so in such a way that the processes necessary for metabolism and reproduction are encoded. the " negative entropy " that schr


. the answer, as we now know, is to be found in the way the dna molecule arranges its elements - - doing so in such a way that the processes necessary for metabolism and reproduction are encoded. the " negative entropy " that schrodinger says is the nourishment of all life is information, and shannon showed exactly how such coding can be done - - in molecules, messages, or switching networks. it has to be said, by the way, that shannon was reluctant to use the word " entropy " to represent this measure implied by his equations, but von neumann told him to go ahead and use it anyway, because " since nobody knows what entropy is, in a debate you will be sure to have an advantage. " remember that entropy is where shannon ended up, not where he started. hot molecules and dna were far from his original intention. he got to the guessing game and the notion of bits and the relationship between uncertainty and entropy because he looked closely at what a message really is. how does a signal that conveys information differ from everything else that happens? how much energy must be put into broadcasting a voice over the radio to be sure that it will be understood despite atmospheric interference or static from other sources? these were the questions that shannon set out to answer. shannon ' s 1948 publication ( " a mathematical theory of information " ) presented a set of theorems that were directly related to the economical and efficient transmission of messages on noisy media, and indirectly but still fundamentally related to the connection between energy and information. shannon ' s work was a direct answer to an engineering problem that had not decreased in importance since the war : how can messages be coded so that they will be reliably transmitted and received over a medium where a certain amount of noise is going to garble reception? shannon showed that any message can be transmitted with as high a reliability as one wishes, by devising the right code. the limit imposed by nature is concerned only with the limit of the communication channel. as long as there is a channel, no matter how noisy, a code can be devised to transmit any message with any degree of certainty. entropy is a measure of the relationship between the complexity of the code and the degree of certainty. these theorems meant a lot to radio and telephone engineers, and made color television as well as broadcasts from the moon possible, but shannon stated them in a way that demonstrated their universality beyond the domain of electrical engineering. the key to life itself, in fact, turned out to be a matter


telephone engineers, and made color television as well as broadcasts from the moon possible, but shannon stated them in a way that demonstrated their universality beyond the domain of electrical engineering. the key to life itself, in fact, turned out to be a matter of information, as the world learned five years later, when that young physicist - turned - biologist who had attended schrodinger ' s lecture, francis crick, teamed up with james watson to decipher the molecular genetic coding of the dna helix. scientifically, and on the level of consciousness, people seemed to jump rather too quickly to make the transition from an energy - based metaphor of the universe to an information model. the rush to generalize information theory to all sorts of scientific areas, some of them of dubious scientific merit, led shannon to decry this " bandwagon effect, " remarking that information theory " has perhaps ballooned to an importance beyond its actual accomplishments.... seldom do more than a few of nature ' s secrets give way at one time. " despite shannon ' s disclaimer, information - and communication - based models have proved to be enormously useful in the sciences because so many important phenomena can be seen in terms of messages. human bodies can be better understood as complex communication networks than as clockwork - like machines. the error - correcting codes guaranteed by shannon ' s " noisy channel " theorem are just as useful for genetic control of protein synthesis as for protocols in a computer network. shannon ' s mit colleague, noam chomsky, has used a similar tool in his exploration of the " deep structure " of language. with all these higher - level abstractions, shannon did not abandon all thought of the potential of digital computers. where wiener saw the computer as a self controlling mechanism and von neumann saw a device with logical as well as mathematical properties, shannon tended to think of eniac and univac as information processing machines. like turing and other mathematicians since then, shannon was fascinated with the idea that something as sophisticated and essentially human as chess playing could, in theory, be emulated by some future version of these devices. in february, 1950, shannon published " a chess playing machine " in the scientific american. half a decade before anyone dared to name the endeavor " artificial intelligence research, " shannon pointed out what a very few people then recognized - - that electronic digital computers could " be adapted to work symbolically with elements representing words, propositions or other conceptual entities. " a chess game is a turing machine. and


intelligence research, " shannon pointed out what a very few people then recognized - - that electronic digital computers could " be adapted to work symbolically with elements representing words, propositions or other conceptual entities. " a chess game is a turing machine. and a universal turing machine, given the properly coded rules, ought to be able to play chess. shannon pointed out that the way most people would design a machine to play chess - - to mechanically examine each alternative move and evaluate it, the so - called brute - force method - - would be virtually impossible, even on the fastest imaginable computer. he estimated that a typical chess game has about 10 ^ 120 possible moves, so " a machine calculating one variation each millionth of a second would require over 10 ^ 95 years to decide on its first move! " this " combinatorial explosion " - - the rapid and overwhelming buildup of alternatives in any system in which each level leads to two or more deeper levels - - was another one of those secrets of nature that claude shannon was in the habit of turning up. the explosive expansion of the number of alternative decisions is a barrier that confronts any attempt to exhaustively examine a branching structure, and continues to confront programmers who seek to emulate cognitive functions by performing searches through problem spaces. turing and shannon were altogether serious in their interest in chess, because of the complexity of the game in relation to the simplicity of its rules, and because they suspected that the shortcut needed to perform this kind of time - consuming search - procedure would also be a clue to the way brains solved all sorts of problems. a chess playing program was also interesting because it was a relative of the kind of informational entities known as automata that von neumann and turing had been toying with. once again, like turing ' s universal machines, these automata were theoretical devices that did not exist at that time, but were possible to build, in principle. for years, shannon experimented with almost absurdly simple homemade versions - - mechanical mice that were able to navigate simple mazes. in 1953, shannon wrote a paper, " computers and automata, " in which he posed questions that continue to be of acute interest to psychologists as well as computerists. can a chess playing computer learn form its mistakes? is it possible to build a machine that can diagnose itself and repair its own malfunctions? can computer programs ( " virtual machines " ) be created that enable computers to write their own software to the specifications of the human user? can the way human brains


mastering the matrixby sam chupp mastering the matrixby sam chupp mastering the matrix by sam chupp ' ma - trik - s & z / etymology : latin, female animal used for breeding, parent plant, from matr -, mater 1 : something within or from which something else originates, develops, or takes form i have been working on world - building and story - creation since i was 8 years old. one of the things i ' ve learned about creating for games is that it is important to create only that which you truly need to create. the trick is knowing what you will need to create and what you can leave behind. sometimes having just a name or a tiny sliver of an idea is enough to get you through the game session. in this column, i intend to first talk about my matrix method and then apply it to several possible world - building and story - creation tasks to demonstrate the strength of this method. what is the matrix? the central idea of the matrix is that everything is related. because of this, you can take a very sketchy amount of info and, using what you do know, more easily create what you do not know. the matrix i ' m going to discuss first is two - dimensional. think of a gridwork of ten rows by ten columns. along the columns we have a list of the common descriptors for each entity we ' re going to be describing. down the rows is each entity. so, if we have a set of characters, for example, the columns will contain information that will be common to each and every character. each row will be a character in and of himself. those of you who use spreadsheets will immediately recognize this structure. it ' s true that spreadsheet software makes for an excellent matrix tool. those of you who happen to play with databases on computers will recognize each row as a " record " and each column as a " field " in database parlance. those of you familiar with recipe card boxes will recognize each row as a recipe card, and each column as an ingredient or instruction for that recipe. get yourself a spreadsheet or buy some index cards in order to properly use the matrix, you ' re going to need to have some way to manipulate the information easily and quickly. in my opinion, the best way to do this is to utilize a spreadsheet program. if you don ' t have bill gates ' expensive one, then you can download a nice one from the people at openoffice. org. but let


exploiting the definitions of pattern using methods and concepts in garment and building construction, the goal of this project is to produce a new type of surface that exists somewhere between the rigid modular assembly of the wall and the body - specific garment. a broader definition of architecture is examined, which implies a variety of interactions with our built environment and the ability to challenge our own bodies, as well as how we relate to each other. this is not an attempt to make a surface that can literally be applied to both body and space, but to make a new type of skin that challenges interaction with the surroundings. methods in patterning are explored based on two definitions : pattern as a model for reproduction ; and two - and three - dimensional patterns as a visual recognition and / or a systematic arrangement through material properties and connections. pattern - making as a model for reproduction inherently implies a prefabricated and standardized system, within which the ideal of production efficiency can be paired with customization. systematic arrangement and visual recognition are inherent in typical construction methods because of the repetitive assembly of standardized parts. beginning with the cube as both a basic building block and an elemental architectural volume, it is deconstructed ; its surface is unfolded and manipulated, creating new patterns for building components. initially, the patterns are developed in heavy paper and three new modules are formed and assembled in aggregations - both as homogeneous arrays and as complex, heterogeneous fabrics. based on the material properties and behaviors in paper, the patterns are tested for layout efficiencies, feasibility for production in a variety of materials, connective ability and overall visual impression. ultimately, these pattern developments result in the fabrication of a self - structured surface from light - gauge aluminum with a variety of speculative applications. [ selected photos : albert chao ]


gallium arsenide - a compound used to make certain types of solar photovoltaic cells. gasification - the process in which a solid fuel is converted into a gas ; also known as pyrolitic distillation or pyrolysis. production of a clean fuel gas makes a wide variety of power options available. gasifier - a device for converting a solid fuel to a gaseous fuel. gasket / seal - a seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure. gasohol - a registered trademark of an agency of the state of nebraska, for an automotive fuel containing a blend of 10 percent ethanol and 90 percent gasoline. gasoline - a refined petroleum product suitable for use as a fuel in internal combustion engines. gas turbine - a type of turbine in which combusted, pressurized gas is directed against a series of blades connected to a shaft, which forces the shaft to turn to produce mechanical energy. gauss - the unit of magnetic field intensity equal to 1 dyne per unit pole. generator - a device for converting mechanical energy to electrical energy. geopressurized brines - these brines are hot ( 300 f to 400 f ) ( 149 c to 204 c ) pressurized waters that contain dissolved methane and lie at depths of 10, 000 ft ( 3048 m ) to more than 20, 000 ft ( 6096 m ) below the earth ' s surface. the best known geopressured reservoirs lie along the texas and louisiana gulf coast. at least three types of energy could be obtained : thermal energy from high - temperature fluids ; hydraulic energy from the high pressure ; and chemical energy from burning the dissolved methane gas. geothermal energy - energy produced by the internal heat of the earth ; geothermal heat sources include : hydrothermal convective systems ; pressurized water reservoirs ; hot dry rocks ; manual gradients ; and magma. geothermal energy can be used directly for heating or to produce electric power. geothermal heat pump - a type of heat pump that uses the ground, ground water, or ponds as a heat source and heat sink, rather than outside air. ground or water temperatures are more constant and are warmer in winter and cooler in summer than air temperatures. geothermal heat pumps operate more efficiently than " conventional " or " air source " heat pumps. geothermal power station - an electricity generating facility that uses geothermal energy. gigawatt ( gw ) - a unit of power equal to 1 billion watts ; 1 million kilow


efficiently than " conventional " or " air source " heat pumps. geothermal power station - an electricity generating facility that uses geothermal energy. gigawatt ( gw ) - a unit of power equal to 1 billion watts ; 1 million kilowatts, or 1, 000 megawatts. gin pole - a pole used to assist in raising a tower. glare - the discomfort or interference with visual perception when viewing a bright object against a dark background. glazing - a term used for the transparent or translucent material in a window. this material ( i. e. glass, plastic films, coated glass ) is used for admitting solar energy and light through windows. glauber ' s salt - a salt, sodium sulfate decahydrate, that melts at 90 degrees fahrenheit ; a component of eutetic salts that can be used for storing heat. glazing - transparent or translucent material ( glass or plastic ) used to admit light and / or to reduce heat loss ; used for building windows, skylights, or greenhouses, or for covering the aperture of a solar collector. global insolation ( or solar radiation ) - the total diffuse and direct insolation on a horizontal surface, averaged over a specified period of time. global warming - a popular term used to describe the increase in average global temperatures due to the greenhouse effect. governor - a device used to regulate motor speed, or, in a wind energy conversion system, to control the rotational speed of the rotor. grain alcohol - ethanol. greenhouse effect - a popular term used to describe the heating effect due to the trapping of long wave ( length ) radiation by greenhouse gases produced from natural and human sources. greenhouse gases - those gases, such as water vapor, carbon dioxide, tropospheric ozone, methane, and low level ozone that are transparent to solar radiation, but opaque to long wave radiation, and which contribute to the greenhouse effect. greenwood - freshly cut, unseasoned, wood. greenpower - a popular term for energy produced from renewable energy resources. green pricing and marketing - to price and sell greenpower / electricity higher than that produced from fossil or nuclear power plants, supposedly because some buyers are willing to pay a premium for greenpower. greywater - waste water from a household source other than a toilet. this water can be used for landscape irrigation depending upon the source of the greywater. grid - a commmon term refering to an electricity transmission and distribution system. gross calorific value - the


about the mean ; an important measure of the dispersion of the distribution. - standard deviation : the square root of the variance, and hence another measure of dispersion. - symmetry : a property of some distributions in which the portion of the distribution to the left of a specific value is a mirror image of the portion to its right. - skewness : a measure of the extent to which a pmf or pdf " leans " to one side of its mean. cumulative distribution function because a probability distribution pr on the real line is determined by the probability of a scalar random variable x being in a half - open interval ( - ∞, x ], the probability distribution is completely characterized by its cumulative distribution function : discrete probability distribution a discrete probability distribution shall be understood as a probability distribution characterized by a probability mass function. thus, the distribution of a random variable x is discrete, and x is then called a discrete random variable, if as u runs through the set of all possible values of x. it follows that such a random variable can assume only a finite or countably infinite number of values. for the number of potential values to be countably infinite even though their probabilities sum to 1 requires that the probabilities decline to zero fast enough : for example, if for n = 1, 2,..., we have the sum of probabilities 1 / 2 + 1 / 4 + 1 / 8 +... = 1. in cases more frequently considered, this set of possible values is a topologically discrete set in the sense that all its points are isolated points. but there are discrete random variables for which this countable set is dense on the real line ( for example, a distribution over rational numbers ). among the most well - known discrete probability distributions that are used for statistical modeling are the poisson distribution, the bernoulli distribution, the binomial distribution, the geometric distribution, and the negative binomial distribution. in addition, the discrete uniform distribution is commonly used in computer programs that make equal - probability random selections between a number of choices. cumulative density equivalently to the above, a discrete random variable can be defined as a random variable whose cumulative distribution function ( cdf ) increases only by jump discontinuities — that is, its cdf increases only where it " jumps " to a higher value, and is constant between those jumps. the points where jumps occur are precisely the values which the random variable may take. delta - function representation consequently, a discrete probability distribution is


the essays included in the special issue dedicated to the philosophy of computer science examine new philosophical questions that arise from reflection upon conceptual issues in computer science and the insights such an enquiry provides into ongoing philosophical debates. we examine the philosophical disputes among computer scientists concerning methodological, ontological, and epistemological questions : is computer science a branch of mathematics, an engineering discipline, or a natural science? should knowledge about the behaviour of programs proceed deductively or empirically? are computer programs on a par with mathematical objects, with mere data, or with mental processes? we conclude that distinct positions taken in regard to these questions emanate from distinct sets of received beliefs or paradigms within the discipline : – the rationalist (... ) paradigm, which was common among theoretical computer scientists, defines computer science as a branch of mathematics, treats programs on a par with mathematical objects, and seeks certain, a priori knowledge about their ‘ correctness ’ by means of deductive reasoning. – the technocratic paradigm, promulgated mainly by software engineers and has come to dominate much of the discipline, defines computer science as an engineering discipline, treats programs as mere data, and seeks probable, a posteriori knowledge about their reliability empirically using testing suites. – the scientific paradigm, prevalent in the branches of artificial intelligence, defines computer science as a natural ( empirical ) science, takes programs to be entities on a par with mental processes, and seeks a priori and a posteriori knowledge about them by combining formal deduction and scientific experimentation. we demonstrate evidence corroborating the tenets of the scientific paradigm, in particular the claim that program - processes are on a par with mental processes. we conclude with a discussion in the influence that the technocratic paradigm has been having over computer science. ( shrink )


exotic life beyond earth? looking for life as we don ' t know it scientists at a new interdisciplinary research institute in austria are working to uncover how life might evolve with " exotic " biochemistry and solvents, such as sulphuric acid instead of water. their research... usf study shows first direct evidence of ocean acidification ( physorg. com ) - - seawater in a vast and deep section of the northeastern pacific ocean shows signs of increased acidity brought on by manmade carbon dioxide in the atmosphere - - a phenomenon that carries with... more asteroids could have made life ' s ingredients ( physorg. com ) - - a wider range of asteroids were capable of creating the kind of amino acids used by life on earth, according to new nasa research. one sponge - like material, three different applications ( physorg. com ) - - a new sponge - like material that is black, brittle and freeze - dried ( just like the ice cream astronauts eat ) can pull off some pretty impressive feats. designed by northwestern university chemists, it can... scientists sound acid alarm for plankton the microscopic organisms on which almost all life in the oceans depends could be even more vulnerable to increasingly acidic waters than scientists realised, according to a new study. scientists sound alarm at arctic ocean ' s rapid acidification scientists expressed alarm on monday over the rapid acidification of the arctic ocean caused by carbon dioxide emissions, which could have dire consequences on the region ' s fragile ecosystem. arctic studies show dire effect of ocean acidity the icy arctic waters around norway ' s archipelago of svalbard may seem pristine and clear, but like the rest of the world ' s oceans they are facing the threat of growing acidity. one sponge - like material, three different applications a new sponge - like material that is black, brittle and freeze - dried ( just like the ice cream astronauts eat ) can pull off some pretty impressive feats. designed by northwestern university chemists, it can remove mercury from... team identifies proton pathway in photosynthesis ( phys. org ) — a purdue university - led team has revealed the proton transfer pathway responsible for a majority of energy storage in photosynthesis. through photosynthesis, plants, algae and bacteria convert sunlight, carbon... geographic isolation drives the evolution of a hot springs microbe sulfolobus islandicus, a microbe that can live in boiling acid, is offering up its secrets to researchers hardy enough to capture it from the volcanic hot springs where


carbon... geographic isolation drives the evolution of a hot springs microbe sulfolobus islandicus, a microbe that can live in boiling acid, is offering up its secrets to researchers hardy enough to capture it from the volcanic hot springs where it thrives. in a new study, researchers report that p... earth is having a bad acid trip, study finds earth may be overdosing on acid - not the " turn on, tune in, drop out " kind, but the " kill fish, kill coral, kill crops " kind. and it ' s shaping up to be a very bad trip. molecules wrestle for supremacy in creation of superstructures ( physorg. com ) - - research at the university of liverpool has found how mirror - image molecules gain control over each other and dictate the physical state of superstructures. key piece of puzzle sheds light on function of ribosomes ( physorg. com ) - - when ribosomes produce protein in all living cells, they do so through a chemical reaction that happens so fast that scientists have been puzzled. using large quantum mechanical calculations of the reaction... pharmaceutical substances found in waters of donana researchers from the university of seville ( us ) have detected active pharmaceutical substances for the first time in the waters of the donana national park and its surrounding areas. the results suggest eco - toxicological...


optical tweezers have been used by biophysicists since their invention at bell labs in the 1980s, and are typically used to study cellular components. but they have a few drawbacks, not least of which are overheating and inefficiency. so engineers at harvard have been working on a next - gen model they call plasmonic nanotweezers to solve those and other issues with traditional optical tweezers so that tiny particles such as viruses can be isolated, observed, and manipulated. back at bell labs, scientists had shined a laser through a microscope lens to focus it tightly. they found that light, made of electromagnetic waves, creates a gradient force at the point of focus that is capable of attracting a tiny particle and holding it in that beam of light until random motion or some other force knocks it out. the basic limitation of this approach is that a lens cannot focus that beam beyond half the wavelength of light, so if the particle the researchers hope to trap is smaller than the focal spot, they might have trouble trapping it. meanwhile, that focal size limit also places an upper limit on the gradient force generated, and yet a stronger force is required to trap nanoscale particles. so for a conventional optical tweezer to capture nanoscale particles, a high - powered laser is required. … read more


ev · o · lu · tion ( ev - uh - loo - shuh n ) noun 1. a gradual process in which something changes into a different and usually more complex or better form. see synonyms at development. 2. a. the process of developing. b. gradual development. rev · o · lu · tion ( re - və - ˈlu - shən ) noun 1. a. a sudden, radical, or complete change. b. a fundamental change in political organization ; especially : the overthrow or renunciation of one government or ruler and the substitution of another by the governed. c. activity or movement designed to effect fundamental changes in the socioeconomic situation. d. a fundamental change in the way of thinking about or visualizing something : a change of paradigm e. a changeover in use or preference especially in technology from long island ' s storied past to today ' s suburban sprawl to the vision of tomorrow ' s suburbia reinvented. some say change here on our island must be evolutionary. slow, gradual, almost always imperceptible, and, too often, painstaking. others say long island cannot wait for evolution to take its course. a more revolutionary posture, from concept to design to implementation, must catapult our island from stagnation and decline to crowning glory as the very model for the new suburbia. what say you? the community alliance blog, itself transforming in both an evolutionary and revolutionary sense ( blink and you may miss it ; - ), now sets out to explore the very frontiers of long island ' s future. where no town supervisor or county exec has dared to go? perhaps. more so, where you, and the collective, we, the people of long island, would like to see our long island, in five years, ten years, twenty - five years, and far beyond. our blog evolves yet again, taking a revolutionary spin, if you will, making you the blogger, and the blog a public forum where community groups, organizations, and john q. public can offer fresh perspectives on the many ways that we can shape tomorrow ' s long island, today. can we afford to simply sit back, waiting with mild anticipation or placid apathy, long island 2030 ( in one incarnation or another ) a speck on the distant horizon, as evolution ( or de - evolution, as the case appears to have been ) slowly defines the look of our island? must we take up arms


that extra paragraph, higgs suspects, that led to his article being accepted by the american scientific journal physical review letters, and, more importantly, that drew attention. the shoulders of giants at a speech given to colleagues last friday at nikhef, higgs credited the scientists who paved the way for him and who dotted the i ' s and crossed the t ' s of his work. he thanked countless people, including a number of nobel prize winners. among the latter were people like jochiro nambu, who got the idea for spontaneous broken symmetry from superconductor research into particle physics. or phil anderson, who came close, but never drew the same final conclusions that higgs did. or sheldon glashow, abdus salam and steven weinberg, who unified the electromagnetic and weak nuclear forces under the standard model. and the dutch gerard ‘ t hooft and martin veltman, who gave this electroweak force a sturdy theoretical foundation. it was with the electroweak force that the higgs mechanism proved particularly useful. this theory covers the interaction between weightless particles ( the photons of the electroweak force ) and massive particles ( like the w - and z - particles of the weak nuclear force ). only higgs ' mechanism could explain the asymmetrical masses, through the existence of a particle which came to be known as the higgs particle, or higgs boson, since a busy congress in 1972. over the years, physicists became convinced the higgs particle might actually be detectable. indirectly, through precise measurements of the electroweak force at cern and the fermi lab in the united states, they established how. higgs : " and that is when my life as a boson really started. " isn ' t it weird to see billions being invested in pursuit of a particle bearing his own name? " if physicists were looking for a different particle they would have constructed an accelerator just as strong and experiments just as complex, " higgs shrugs. and what if it doesn ' t exist? a different question. what if the higgs particle isn ' t found? " then i no longer understand a whole area of physics which was puzzling to me as an undergraduate, " higgs answers, sounding determined this time. " and i thought the one thing we understand rather well now is the electromagnetic interaction and how it relates to electroweak theory. " it could have been different. when higgs ' manuscript arrived at physical review letters on august 31, 1964


the set of characteristics linked to your background and life that belong only to you. identity is how you and others see yourself. an illusion is something that you see that misleads you into believing that it is something other than what it actually is. for example, a magic trick or voices in the wind. each of the human senses ( vision, hearing, smell, taste, touch ) can be tricked by illusions, but visual illusions are the most well known. drawings or pictures that explain what happens in a book, magazine, or other media such as the internet. a person who makes illustrations, which are drawings or pictures that explain what happens in a book, magazine, or other media such as the internet. visual or written representations of things. a person who moves from one country to another in order to settle and live there. moving from one country to another in order to settle and live there. a deep black, watery ink used especially for drawing and printing. relating to the manufacture of products such as cars or clothes. for example, welding and soldering are two industrial processes used in automobile factories. having no limit. you cannot measure infinity because it is so large! it continues forever without boundaries. installation is the act of setting something up or placing it in position for service or use. an installation is also a work of art made especially for a museum or gallery space or an outdoor site. an installation consists of an entire environment rather than a group of objects like paintings or sculptures that are viewed as individual works. in an installation, the viewer is often surrounded by the art. to explain the meaning ( s ) of something. a feeling of being alone or set apart from others.


an immune system crash and getting an infection and ending up in intensive care, or not having quite enough chemotherapy and the cancer not being quite completely killed and coming back. so for a lot of cancer patients on chemo, their lives involve a constant round of blood tests and trips to the hospital. what i ' d really like to achieve is a sensor that you could put inside a person ' s body that would effectively email you when it was time to stop giving this particular sort of chemo or time to give a different sort of chemo. how in practice can we achieve that? well, one way we could do that is to use a microfluidics. microfluidics a particular branch of engineering that involves taking very, very small channels in a substrate, in this case diamond, about the size of a human hair, probably a little bit bigger in the case of something that ' s going to have blood flowing through it, because blood has fairly large cells in it. when the channel is very, very small, the surface area to volume ratio is very, very, very large, so your walls of your channel can be coated with a sensitive compound and they can access a very large amount of the fluid flowing through it. this is not a new idea, it ' s been very, very popular in biosensing engineering for a long time. for example, people have tried to develop ways to measure the tears coming from a person to try and find out what their kidneys are doing. but what i ' m interested in is implanting this. and the advantage of having such tiny channels is that if you can get your assays, the reactions that detect the presence of particular chemicals or biological products, if you can have those assays very, very small, then they can line the walls of this microfluidic system. so why diamonds? diamond is very, very biocompatible, it ' s unreactive biologically, unless you want it to be. diamond is normally an electrical insulator, which is actually a good thing to have in the bulk of a sensor because that way you don ' t get any leakage currents or cross talks. but the surface can be made very conducting by applying atomic hydrogen to it. in fact, if you put other molecules on top of the hydrogen you get even greater conductivity. what i would like to do is find out ways that conductivity can change in response to the biological reactions that are happening at that surface. i ' m not the first person to have


molecules on top of the hydrogen you get even greater conductivity. what i would like to do is find out ways that conductivity can change in response to the biological reactions that are happening at that surface. i ' m not the first person to have thought of this, but i ' m very excited about the possibility of doing this in a combined package. my research when i finished my doctorate was to look at sensors made out of diamond to try and find out where a charged particle had moved. so, particle detection. but i had my own particular brush with cancer and i was diagnosed with multiple myeloma in my first postdoctoral fellowship. that threw everything into chaos. i was very, very lucky and i had a bone marrow transplant that was relatively successful. those of you who know something about multiple myeloma realise that it has a tendency to come back eventually, but after eight years i ' m still in fairly good shape. but in all of the panic of the cancer and everything, i had a couple of ideas about trying to make some sort of implantable biosensor so that i could really know where my levels were at so i could get the treatment just right. then i went back to work and the idea faded just a little bit. then my son was diagnosed with leukaemia. the thing about young people is that they don ' t always understand what ' s happening to them, and any medical procedure that is invasive is quite traumatic, and getting blood out of a three - year - old is tricky. usually you have to prick their finger, and you can only deal with a very small amount of blood. so being able to implant a sensor into a kid, that would be great. so that ' s my motivation, it is a very personal one for trying to make these implantable biosensors. however, the practicalities of making these devices is quite complex. i don ' t think that i ' m going to be engineering a device like this any time in the near future. but my particular passion is to try and look at the ways that i can sensitise the diamond surface so that it is sensitive to these biological reactions. i think that growing the diamonds or tunnelling into the block of diamond is not the hardest problem, i think that we can actually do that. connecting the diamonds to the circuits so that it can be read out to the outside world is not the hardest problem either. i am particularly interested in that fundamental problem of how do we detect a biological reaction when it ' s happening at


animals, as well as hidden away within their dens. it should come as no surprise that these same environments can supply mustika pearls in abundance. 3. 4 silicon & silicon dioxide silicon is the second most abundant element found on the earth – second only to oxygen. 25. 7 % of our planet ’ s crust is made up of silicon. due to this abundance, silicon is an essential element in biology, despite the fact that animals only require small trace amounts in their diets. however, silicon is much more essential to healthy plant metabolism – especially grasses. according to the results of a study published by the mineralogical society of america, in the year 1928 alone, as many as 35 crystalline forms of silica ( meaning silicon paired with oxygen ) were identified. to understand the diverse manifestation of silica based compounds and minerals, it helps to know that silica is something known as a polymorphous substance. this results in a variety of possible crystalline structures that is practically infinite. categorizing silica as a polymorph means that it ’ s capable of crystallizing into a number of different shapes and structures. these different polymorphous structures will have different and unique atomic arrangements within the cell unit. these variations can have a profound effect on the final resulting crystallized compound. this occurs through a process known as polymorphic transformation. this process is a change that takes place when crystal structures encounter other crystals of the same chemical composition. the resulting unique crystal structures are called polymorphs, which goes to show that various crystal structures are dependent on two very important factors : external temperature and pressure. thanks to these characteristics, it ’ s much easier to understand why silica is such an essential element in the composition of my rock - forming minerals. due to silica ’ s polymorphic properties, its elemental crystalline structures can be found in a multitude of forms. as a matter of fact, many popular rocks and minerals ( quartz crystals and sand, sandstone, quartzite, opal, agate and onyx ) are just a few forms that silica can take on. additionally, modifications of external pressure and temperature not only determine the crystalline structure of the resulting compound, but also their colour. silica - based rocks and gems can be found in a variety of colours, including : - smoky quartz - yellow quartz - rose quartz & - milky quartz 3. 5 soluble silica in plants & animals in theory, we believe that it ’ s entirely possible that our magickal pearls and stones also contain some


a metal is a chemical element which can form metal connections and lose electrons to form cations ( positive ion s ) ( and ionic connections in the case of alkaline ). metals are one of the three groups of elements distinguished by their properties from ion isation and chemical bond ; the two others are the metalloide s and the non - metaux. although metals can be defined by their physicochemical properties ( see further ), it is also possible to categorize them by employing a characterization of their structure of band : metals have valence bands and conduction which is recovered. this definition makes it possible to integrate into the category of metal metals the polymeric and others made up organometallique s. it is however not an always sufficient criterion. for example, carbon is not a metal but it has a named phase graphite ( it is its phase alpha besides ) which corresponds to this definition. metals in the periodic tablein the periodic table of the elements the diagonal on the basis of the boron ( b ) and going until the polonium ( po ) separates the metal elements ( in bottom on the left ) from the nonmetal elements ( in top on the right ). the elements placed on this line are metalloides. moreover, the metal character of the elements of the same column increases with the number of electrons ( i. e. when one goes down in the table ). for example, the carbon - diamond ( z = 6 ) is a isolant, the silicium ( z = 14 ) is a semi - conducteur and the tin ( z = 50 ) is a metal. properties of metals metals are in general solids cristal flaxes ; the mercury is however a notable exception since it is only metal in the liquid state in the normal conditions ( 25 °c under atmospheric pressure ). three other metals are liquid around the room temperature : the cesium, the gallium and the rubidium. they are in general malleable and ductile ( one can deform them for example by stretching them or by hammering them ), they leads well heat and electricity ( but not all ), and they reflect the light ( metallic luster ) except when they are covered with oxide ( corrosion ). most of the time, metals are extracted in mineral form more or less crystallized ( cristal ) in their ores and almost always combined with one or more other atoms. they are often present at the natural state in the form of oxyde, in


the time, metals are extracted in mineral form more or less crystallized ( cristal ) in their ores and almost always combined with one or more other atoms. they are often present at the natural state in the form of oxyde, in minerai s : bauxite for aluminum, hematite for iron, ilmenite or rutile for titanium … the ilmenite, for example, principal ore of titanium is a mixed iron and titanium oxide ( percentage of two metals between 30 and 70 % ). others can be presented in the form of sulfides pyrite for iron or of sulfates, even in more complicated form and even in several different forms as one saw for the fer. certain metals are present at the not - oxidized state, like the noble metals ( gold, platinum ) or in rocks of origin meteoritic ( nickel - fer ). they then are called native. metals conduct generally well electricity and the heat. at the head money, copper and gold. electric conduction in metals can be analyzed in a microscopic or macroscopic way. from a microscopic point of view, the main reason comes from the metal connection. the metal atome s form structures 2d or 3d which are repeated, called meshs. inside, of about free electrons circulate surrounded of the atoms from which they result. it is this electronic movement which is responsible for the good conduction, and more these electrons are free, plus metal is conducting good. these more or less free electrons are called “ electrons of conduction ”. from a macroscopic point of view, it is the theory of the energy bands which provide the answer. indeed, in metals the energy band highest occupied and lowest vacant overlap, or at least are touched. one thus needs little energy to excite a metal and more it is easy to excite it, plus a metal will be able to yield an electron and better conducting it will be. magnetic propertiessome metals present remarkable magnetic properties like the ferromagnetisme, primarily the fer, the cobalt and the nickel with room temperature. the properties of magnetism vary when one makes alliage s what can be made profitable to create powerful aimant s where to cancel the magnetisme of a metal ( iron typically ). chemical speciationthe various states of oxidation, conformations, complexes or forms transitory represent chemical species distinct from an element and exploit an important role their biodisponibility and their toxicity or ecotoxicity. certain species of metal elements