differential absorption lidar ( dial ) light is absorbed by many of the atmospheric components. absorption of light by molecules is the basis for dial which is used to measure the atmospheric concentrations of gases such as water vapor and ozone. dial measurements of water vapor as shown in figure ( a ), water vapor has many discrete absorption lines. in water vapor dial, laser pulses are transmitted at two wavelengths, one on a water vapor absorption line, λon, and another off - line, λoff. if the two wavelengths are close together, then for both wavelengths the scattering by molecules and particles is essentially equal. the difference in the returns between the two wavelengths is then due entirely to absorption by water vapor molecules, figure ( b ). thus, measurement of the ratio of the backscatter at the two wavelengths as a function of range can be used to calculate the water vapor concentration profile. dial measurements of ozone dial measurements of ozone require less precise laser frequency because ozone has a broad ( ~ 200 nm ) absorption band [ see figure ] instead of narrow lines lines like water vapor. this requires that the on - and off - wavelengths be chosen with sufficient wavelength separation to ensure a significant difference in their absorption. however, uncertainty in the changes of aerosol scattering and patterning between the wavelengths can introduce error. the difference in aerosol scattering at λon and λoff can be extrapolated from a third measurement taken at a longer wavelength, λa. therefore, dial measurements with three wavelengths can be used to determine ozone concentration profiles to good accuracy.


see also the browse high school definitions stars indicate particularly interesting answers or good places to begin browsing. - phi [ 05 / 18 / 1997 ] what is phi? - pick ' s theorem, lattice points, and area [ 08 / 27 / 1998 ] what is a lattice point, and how does it relate to the area of a triangle, rectangle, and a circle? - point symmetry [ 08 / 19 / 2001 ] what exactly is point symmetry? how can one tell if point symmetry is - polyhedra : classification, theorem [ 02 / 12 / 1998 ] i would like to know how polyhedrons are classified, which figures can be used for the faces, and the theorem relating the faces, edges, and - polyhedra : solids or surfaces? [ 06 / 06 / 2003 ] is a polyhedron always a solid figure? - polynomial basics and terms [ 05 / 20 / 1998 ] i ' m having a lot of trouble understanding polynomials. - polynomial degrees and definition of a field [ 03 / 02 / 1998 ] the degree of polynomials added together, and definition of a field. - polyominoes [ 09 / 08 / 1997 ] i am using polyominos, but i do not know how to tell my dad what they are. how can i tell him so he will know? - power or exponent? [ 10 / 14 / 2003 ] i always thought that ' power ' was just a synonym for ' exponent '. is - principal square root positive [ 10 / 24 / 2002 ] why are we always taught that the principal square root of a number is - product notation [ 10 / 26 / 2000 ] can the pi symbol also be used to mean multiplying all the terms in a - profit margin and percentage markup [ 02 / 16 / 2007 ] i own a small business and am a little confused about the difference between a percentage markup and a profit margin. are they the same thing? if not, how are they different? - pronumerals [ 05 / 14 / 2002 ] what is a ' pronumeral '? - proofs with isosceles triangles [ 10 / 28 / 1998 ] what are altitudes, angle bisectors, and medians? how do you prove that in an isoseles triangle, the altitude is a median and an angle bisector? - proportionality symbol [ 05 / 20 / 2003 ] do you know the name of the little symbol used in the topic of rates and variation that means ' in proportion to '? - pyramid


and an equilateral - relative and absolute extrema of a function [ 01 / 07 / 2004 ] what is the difference between the absolute extrema and the relative extrema in calculus? - relatively prime [ 10 / 07 / 1999 ] what does the term relatively prime mean, and how can you determine if two numbers are relative primes? - rhombus and square comparison [ 01 / 14 / 2004 ] comparison of the definitions of rhombus and square as a way to answer the questions, ' is a square a rhombus? ' and ' is a rhombus a square? '. - rhombus vs. rhomboid [ 08 / 27 / 2002 ] what is the difference between a rhombus and a rhomboid? - roughing it more rigorously [ 12 / 02 / 2010 ] a physics student wants to make sense of the various symbols used to represent " approximately equal to " - - as well as the phrase ' s mathematical meaning. doctor vogler produces two precise definitions while acknowledging that context, and personal preference, rule the day. - scientific notation and engineering notation [ 10 / 22 / 2003 ] what is the difference between scientific notation and engineering - the second octant [ 04 / 03 / 2002 ] where is the second octant? no one seems to know how to count the next octants after the first. - set, subset, element [ 3 / 10 / 1997 ] please define : set, subset, member, element, intersection, union. - significant non - zero digits [ 11 / 27 / 2001 ] how many significant digits are there in a number with no non - zero digits? example : 00. 000 are there any? - the simplex method [ 11 / 2 / 1996 ] how does the simplex method work and what would i use it for?


see also the 3d and higher browse middle school definitions stars indicate particularly interesting answers or good places to begin browsing. - circle definitions [ 04 / 29 / 2002 ] define a circle and its parts : diameter, radius, center, - circumference vs. perimeter [ 05 / 09 / 2003 ] technically speaking, can the term ' perimeter ' apply to a circle in a - clarifying percentages vs. percentage points [ 11 / 21 / 2003 ] what is the difference between measuring using percentages versus measuring using percentage points? what is meant by a percentage point? - clockwise and counterclockwise [ 03 / 19 / 2001 ] what does clockwise mean? - a closer look at the definition of median [ 08 / 14 / 2008 ] if you have five numbers like 100, 200, 300, 400, 500, the median or middle number is 300. how does this divide the set of numbers into two equal groups? - comparing transitivity and substitution [ 10 / 01 / 2003 ] what is the difference between transitivity and substitution? - complementary and supplementary angles [ 09 / 30 / 1998 ] why are angles called complementary and supplementary? - complementary and supplementary angles [ 10 / 24 / 1999 ] definitions of complementary and supplementary angles. - complementary or supplementary? [ 04 / 02 / 2001 ] i keep getting complementary and supplementary mixed up. how can i remember which is which? - concave and convex polygons [ 08 / 13 / 2001 ] what ' s the difference between a convex and a concave polygon? - concept of factoring [ 03 / 22 / 1997 ] could you explain the concept of factoring and give examples of its - congruent fractions [ 04 / 03 / 1997 ] what are congruent fractions? - converting to bushels [ 05 / 18 / 2002 ] how can i convert cubic feet to bushels? - convex and concave polygons [ 3 / 23 / 1996 ] what are convex and concave polygons? - correct usage of equal and equivalent in math statements [ 02 / 20 / 2008 ] is there a mathematical difference between " equal " and " equivalent "? - cubic centimeter, cubic inch [ 08 / 26 / 1997 ] can you help me define these terms? - cubic centimeters and milliliters [ 10 / 29 / 2001 ] i know that cubic centimeters and milliliters are the same thing, but is there any way you can prove it to me? - cute numbers [ 08 / 29 / 2003 ] i have found two definitions of a


of interpolate [ 10 / 27 / 1995 ] could you please define interpolate and give me an example? - definition of mixed number [ 11 / 22 / 2004 ] is 5 a mixed number? why or why not? i think it is, because you can write 5 0 / 3, can ' t you? - definition of negative square roots [ 03 / 08 / 2004 ] i know that the square root of 49 = 7 since 7 x 7 = 49. but the negative square root of 49 is - 7. is this because ( - 7 ) x ( - 7 ) also equals 49 or because the square root of 49 is 7 and the negative stays because it is not involved with the operation? my teacher wrote - sqrt ( 49 ) = - 7 because ( - 7 ) x ( - 7 ) = 49. - definition of opposite sides [ 01 / 18 / 2001 ] what is the formal definition of ' opposite sides ' of a polygon? does a regular pentagon have opposite sides? does a concave polygon have opposite sides? how can we define it consistent with our intuition? - definition of oval [ 06 / 09 / 2002 ] can you give a precise definition of ' oval '? - definition of quotient [ 11 / 13 / 2008 ] if i divide 15 by 2, i always thought that the quotient was 7 and the remainder was 1. but i ' ve seen that the quotient can also be 15 / 2. how can quotient have different meanings? - definition of repetend [ 9 / 17 / 1995 ] what is the definition of repetend? where can i find its definition on - definition of ' solve ' [ 11 / 29 / 2005 ] in algebra class i was told that a problem such as 2 + 2 cannot be solved. in order to ' solve ' a problem there has to be a variable involved. is this correct? - definition of vinculum [ 10 / 21 / 2004 ] is the bar placed over the set of repeated digits in a repeating decimal called a vinculum? i ' ve heard that but i can ' t confirm it. - definitions : average, mean, mode [ 5 / 20 / 1996 ] arithmetic, geometric, harmonic means defined.


the chemical elements, known and as yet unknown, and energy in all of its forms — are virtually infinite in their extent. in this sense, nature ’ s contribution is boundless. even if we limit our horizon exclusively to the planet earth, which certainly need not be our ultimate limit, the magnitude of natural resources supplied by nature is mind - bogglingly huge. it is nothing less than the entire mass of the earth and all of the energy that goes with it, from thunder storms in the atmosphere, a single one of which discharges more energy than all of mankind produces in an entire year, to the tremendous heat found at the earth ’ s core in millions of cubic miles of molten iron and nickel. yes, the natural resources provided by nature in the earth alone extend from the upper limits of the earth ’ s atmosphere, four - thousand miles straight down, to its center. this enormity consists of solidly packed chemical elements. there is not one cubic centimeter of the earth, either on its surface or anywhere below its surface, that is not some chemical element or other, or some combination of chemical elements. this is nature ’ s contribution to the natural resources contained in this planet. it indicates the incredibly enormous extent of what is out there awaiting transformation by man into natural resources possessing goods - character. and this brings me to what i consider to be the revolutionary view of natural resources that is implied in menger ’ s theory of goods. namely, not only does man create the goods - character of natural resources — by obtaining knowledge of their useful properties and then creating their useability and accessibility by virtue of establishing the necessary command over them — but he also has the ability to go on indefinitely increasing the supply of natural resources possessing goods - character. he enlarges the supply of useable, accessible natural resources — that is, natural resources possessing goods - character — as he expands his knowledge of and physical power over nature. the prevailing view, that dominates the thinking of the environmentalists and the conservationists, that there is a scarce, precious stock of natural resources that man ’ s productive activity serves merely to deplete is wrong. seen in its full context, man ’ s productive activity serves to enlarge the supply of useable, accessible natural resources by converting a larger, though still tiny, fraction of nature into natural resources possessing goods - character. the essential question concerning natural resources is what fraction of the virtual infinity that is nature does man possess sufficient knowledge concerning and sufficient physical command over to be able to direct it to


supports for mine shafts, and modern pumps and engines. today, a single worker operating a bulldozer or steam shovel can move far more earth than hundreds of workers in the past using hand shovels. advances in reduction methods have made it possible to obtain pure ores from compounds previously either altogether impossible to work with or at least too costly to work with. improvements in shipping, railroad building, and highway construction have made possible low - cost access to high - grade mineral deposits in regions previously inaccessible or too costly to exploit. and, i added : there is no limit to the further advances that are possible. reductions in the cost of extracting petroleum from shale and tar sands have the potential for expanding the supply of economically useable petroleum by a vast multiple of what it is today. hydrogen, the most abundant element in the universe, may turn out to be an economical source of fuel in the future. atomic and hydrogen explosives, lasers, satellite detection systems, and, indeed, even space travel itself, open up limitless new possibilities for increasing the supply of economically useable mineral supplies. advances in mining technology that would make it possible to mine economically at a depth of, say, ten thousand feet, instead of the present much more limited depths, or to mine beneath the oceans, would so increase the portion of the earth ’ s mass accessible to man that all previous supplies of accessible minerals would appear insignificant in comparison ( p. 64 ). the key point here is that, following menger ’ s insights into the nature of goods, the supply of economically useable, accessible natural resources is expandable. it is enlarged as part of the same process by which man increases the production and supply of all other goods, namely, scientific and technological progress and saving and capital accumulation. the fundamental situation is this. nature presents the earth as an immense solidly packed ball of chemical elements. it has also provided comparably incredible amounts of energy in connection with this mass of chemical elements. if, over and against this massive contribution from nature stands motivated human intelligence — the kind of motivated human intelligence that a free, capitalist society so greatly encourages, with its prospect of earning a substantial personal fortune as the result of almost every significant advance, there can be little doubt as to the outcome : man will succeed in progressively enlarging the fraction of nature ’ s contribution that constitutes goods ; that is, he will succeed in progressively enlarging the supply of useable, accessible natural resources. the likelihood of his success is greatly reinforced by two closely related facts : the progressive


goods of lower order. all that it is necessary to add to menger ’ s view is recognition once again of the fact that the earth is an immense ball of solidly packed chemical elements. now these chemical elements constitute man ’ s external material surroundings, i. e., his environment. they are the external material conditions of human life. when these facts are kept in mind, it becomes clear that the process of production, and the whole of economic activity, so far from constituting a danger to man ’ s environment, as the environmentalists claim, have the inherent tendency to improve his environment, indeed, that that is their essential purpose. this becomes obvious as soon as one realizes that not only does the entire world physically consist of nothing but chemical elements, but also that these elements are never destroyed. they simply reappear in different combinations, in different proportions, in different places. as i wrote in capitalism : apart from what has been lost in a few rockets, the quantity of every chemical element in the world today is the same as it was before the industrial revolution. the only difference is that, because of the industrial revolution, instead of lying dormant, out of man ’ s control, the chemical elements have been moved about, as never before, in such a way as to improve human life and well - being. for instance, some part of the world ’ s iron and copper has been moved from the interior of the earth, where it was useless, to now constitute buildings, bridges, automobiles, and a million and one other things of benefit to human life. some part of the world ’ s carbon, oxygen, and hydrogen has been separated from certain compounds and recombined in others, in the process releasing energy to heat and light homes, power industrial machinery, automobiles, airplanes, ships, and railroad trains, and in countless other ways serve human life. it follows that insofar as man ’ s environment consists of the chemical elements iron, copper, carbon, oxygen, and hydrogen, and his productive activity makes them useful to himself in these ways, his environment is correspondingly improved. consider further examples. to live, man needs to be able to move his person and his goods from place to place. if an untamed forest stands in his way, such movement is difficult or impossible. it represents an improvement in his environment, therefore, when man moves the chemical elements that constitute some of the trees of the forest somewhere else and lays down the chemical elements brought from somewhere else to constitute a road. it is an


substitution ciphers that encode a message by substituting one character for another go back at least as far as julius caesar, who used a rotating character scheme to encode military orders. this simple type of encryption is vulnerable to statistical attacks, however, as anyone who has solved cryptogram puzzles can attest. in world war ii, the nazi military employed an encryption scheme that addressed this weakness of simple substitution ciphers. this scheme, implemented by typewriter - sized devices known as enigma machines, gave the nazis a tactical advantage that greatly contributed to their early success in the war. in fact, the eventual breaking of this coding scheme by researchers at bletchley park, england ( including alan turing ) is hailed as one of the turning points of the war. enigma machines used interchangeable rotors that could be placed in different orientations to obtain different substitution patterns. more significantly, the rotors rotated after each character was encoded, changing the substitution pattern and making the code very difficult to break. the behavior of the rotating rotors can be modeled, in a simplified form, by a device consisting of labeled, concentric rings. for example, the model below has three rings labeled with the letters of the alphabet and ' # ' ( representing a space ). to encrypt a character using this model, find the character on the inner rotor ( i. e., the inside ring ) and note the character aligned with it on the outer rotor ( i. e., the outside ring ), then find that character on the middle rotor ( i. e., the middle ring ) and output the one aligned with it on the outer rotor. after a character is encrypted, turn the inner rotor clockwise one step. whenever the inner rotor returns to its original orientation, the middle rotor turns once in lock - step, just like the odometer in a car. for example, in this configuration the character ' a ' would be encrypted as ' n ', since ' a ' on the inner rotor is aligned with ' h ' on the outer rotor, and ' h ' on the middle rotor is aligned with ' n ' on the outer rotor. after performing this encryption, the inner rotor is rotated clockwise, so the letter ' a ' would next be encrypted as ' d '. note that decrypting a message requires following the same steps, only in reverse ( i. e., find the character on the outer rotor, note the character aligned with it on the middle rotor


encrypted as ' d '. note that decrypting a message requires following the same steps, only in reverse ( i. e., find the character on the outer rotor, note the character aligned with it on the middle rotor, find that character on the outer rotor, then output the character aligned with it on the inner rotor ). for this assignment, you are to design a java class named enigma that simulates this three - ring model. you may assume that all enigma models have the same outer rotor, as shown in the above diagram. that is, the outer rotor consists of the 26 capital letters and the ' # ' symbol ( representing a space ) in the following clockwise order : # bdfhjlnprtvxzacegikmoqsuwy. since the other rotors are interchangeable, however, their contents and alignment relative to the outer rotor must be specified when constructing an enigma model. for example, the initial settings of the inner and middle rotors in the above diagram are # gnuahovbipwcjqxdkryelszfmt and # ejotychmrwafkpuzdinsxbglqv, respectively. using an enigma object, it should be possible to encode and decode text messages, with the appropriate rotation of the rotors occurring after each character encoding / decoding. you should also design and implement a graphical user interface that makes it simple for the user to specify the rotor settings on an enigma model, and encode or decode text. once you have your model working, test it by decoding the message oknnwrdhgerpilrlamfzf # fmuc using the diagram settings. note : if you would like to make your own 3 - ring enigma model out of paper, download this online form, cut out the rings, and follow the instructions at the site.


australasian journal of philosophy 84 ( 1 ) : 59 – 73 ( 2006 ) | abstract | | ' philosophy arises through misconceptions of grammar ', said wittgenstein. few people have believed him, and probably none, therefore, working in the area of the philosophy of mathematics. yet his assertion is most evidently the case in the philosophy of set theory, as this paper demonstrates ( see also rodych 2000 ). the motivation for twentieth century set theory has rested on the belief that everything in mathematics can be defined in terms of sets [ maddy 1994 : 4 ]. but not only are there notable items which cannot be so defined, including numbers and mereological sums, the very notion of a set, as formalized within this tradition, is based on a series of grammatical confusions. | | keywords | | no keywords specified ( fix it ) | | through your library | | configure | similar books and articles emily carson ( 1996 ). on realism in set theory. philosophia mathematica 4 ( 1 ) : 3 - 17. john mayberry ( 1994 ). what is required of a foundation for mathematics? philosophia mathematica 2 ( 1 ) : 16 - 35. f. a. muller ( 2001 ). sets, classes, and categories. british journal for the philosophy of science 52 ( 3 ) : 539 - 573. john j. ross ( 2009 ). reading wittgenstein ' s philosophical investigations : a beginner ' s guide. lexington books. siegfried gottwald ( 2006 ). universes of fuzzy sets and axiomatizations of fuzzy set theory. part i : model - based and axiomatic approaches. studia logica 82 ( 2 ) : 211 - 244. jose ferreiros ( 2011 ). on arbitrary sets and zfc. bulletin of symbolic logic 17 ( 3 ) : 361 - 393. emmon bach, actl semantics : compositionality and morphosemantics : ii : words, morphemes, constructions, interpretations. john p. burgess ( 1988 ). sets and point - sets : five grades of set - theoretic involvement in geometry. psa : proceedings of the biennial meeting of the philosophy of science association 1988 : 456 - 463. added to index2009 - 01 - 28 total downloads12 ( # 93, 408 of 549, 122 ) recent downloads ( 6 months ) 1 ( # 63, 361 of 549


a breakthrough in the harnessing of ' t - rays ' - electromagnetic terahertz waves - which could dramatically improve the detecting and sensing of objects as varied as biological cell abnormalities and explosives has been announced. researchers at the university of bath, uk, and in spain have said they have found a way to control the flow of terahertz radiation down a metal wire. their findings are set out in a letter published in the current journal physical review letters. terahertz radiation, whose frequency is around one thousand billion cycles a second, bridges the gap between the microwave and infrared parts of the electromagnetic spectrum. materials interact with radiation at t - ray frequencies in different ways than with radiation in other parts of the spectrum, making t - rays potentially important in detecting and analysing chemicals by analysing how they absorb t - rays fired at them. this would allow quality control of prescribed drugs and detection of explosives to be carried out more easily, as many complex molecules have distinctive signatures in this part of the electromagnetic spectrum. t - ray applications are presently limited by the relatively poor ability to focus the rays, which is achieved using the conventional means of lenses and mirrors to focus the radiation. this limits the spot size of focused t - rays to a substantial fraction of a millimetre and this has made studies of small objects such as biological cells with high resolution are virtually impossible. but in their work the researchers found that although ordinary metal wire would not guide t - rays very well, if a series of tiny grooves was cut into the wire, it would do so much more effectively. if such a corrugated metal wire is then tapered to a point it becomes possible to very efficiently transport radiation to a point as small as a few millionths of a metre across. this might, for example, lead to breakthroughs in examining very small objects such as the interior of biological cells where it might be possible to detect diseases or abnormalities. t - rays could also be directed to the interior of objects which could be useful in applications like endoscopic probing for cancerous cells or explosive detection. " this is a significant development that would allow unprecedented accuracy in studying tiny objects and sensing chemicals using t - rays " said dr stefan maier, of the university of bath ' s department of physics, who leads the research. " metal wire ordinarily has a limited ability to allow t - rays to flow along it, but our idea was to overcome this by corrugating its surface with a series of grooves, in effect creating an artificial material or '


, and actors. the term " stage " in this context was chosen to allude to the stage theories, but not in the strict definition that includes irreversibility and invariance. the terms " phase " or " mindset " may be equally suitable for this distinction. the basic idea is that individuals pass through different mindsets on their way to behavior change. thus, interventions may be most efficient when tailored to these particular mindsets. for example, nonintenders are supposed to benefit from confrontation with outcome expectancies and some level of risk communication. they need to learn that the new behavior ( e. g., becoming physically active ) has positive outcomes ( e. g., well - being, weight loss, fun ) as opposed to the negative outcomes that accompany the current ( sedentary ) behavior ( such as developing an illness or being unattractive ). in contrast, intenders should not benefit from such a treatment because, after setting a goal, they have already moved beyond this mindset. rather, they should benefit from planning to translate their intentions into action. finally, actors do not need any treatment at all unless one wants to improve their relapse prevention skills. then, they should be prepared for particular high - risk situations in which lapses are imminent. this can be done by teaching them to anticipate such situations and by acquiring the necessary levels of perceived recovery self - efficacy. there are quite a few randomized controlled trials that have examined the notion of stage - matched interventions based on hapa, for example in the context of dietary behaviors, physical activity, and dental hygiene. - ↑ conner, m., & norman, p. ( eds. ). ( 2005 ). predicting health behavior : research and practice with social cognition models ( 2nd ed. ). buckingham, england : open university press. - ↑ sniehotta, f. f. ( 2009 ). towards a theory of intentional behaviour change : plans, planning, and self - regulation. british journal of health psychology, 14, 261 – 273. - ↑ biddle, s. j. h., & fuchs, r. ( 2009 ). exercise psychology : a view from europe. psychology of sport and exercise, 10, 410 – 419. - ↑ sutton, s. ( 2005 ). stage models of health behaviour. in m. conner & p. norman ( eds. ), predicting health behaviour : research and practice with social cognition models ( 2nd ed., pp. 223 – 275


to improve energy storage technologies, and we ' re confident that substantial progress will be made. we can, however, use thermodynamics to calculate the upper limits of what ' s possible for a variety of technologies. and when we do this, we find that many technologies will never compete with fossil carbon on energy density. let ' s start with batteries. today ' s lead acid batteries can store about 0. 1 mega - joules per kilogram, or about 500 times less than crude oil. those batteries, of course, could be improved, but any battery based on the standard lead - oxide / sulfuric acid chemistry is limited by foundational thermodynamics to less than 0. 7 mega - joules per kilogram. due to the theoretical limits of lead - acid batteries, there has been serious work on other approaches such as lithium - ion batteries, which usually involve the oxidation and reduction of carbon and a transition metal such as cobalt. these batteries have already improved upon the energy density of lead - acid batteries by a factor of about 6 to around 0. 5 mega - joules per kilogram - - a great improvement. but as currently designed, they have a theoretical energy density limit of about 2 mega - joules per kilogram. and if research regarding the substitution of silicon for carbon in the anodes is realized in a practical way, then the theoretical limit on lithium - ion batteries might break 3 mega - joules per kilogram. therefore, the maximum theoretical potential of advanced lithium - ion batteries that haven ' t been demonstrated to work yet is still only about 6 percent of crude oil! but what about some ultra - advanced lithium battery that uses lighter elements than cobalt and carbon? without considering the practicality of building such a battery, we can look at the periodic table and pick out the lightest elements with multiple oxidations states that do form compounds. this thought experiment turns up compounds of hydrogen - scandium. assuming that we could actually make such a battery, its theoretical limit would be around 5 mega - joules per kilogram. so the best batteries are currently getting 10 percent of a physical upper bound and 25 percent of a demonstrated bound. and given other required materials such as electrolytes, separators, current collectors, and packaging, we ' re unlikely to improve the energy density by more than about a factor of 2 within about 20 years. this means hydrocarbons - - including both fossil carbon and biofuels - - are still a factor of 10 better than the physical upper bound,


re unlikely to improve the energy density by more than about a factor of 2 within about 20 years. this means hydrocarbons - - including both fossil carbon and biofuels - - are still a factor of 10 better than the physical upper bound, and they ' re likely to be 25 times better than lithium batteries will ever be. what about storing energy in electric fields ( i. e., capacitors ) or magnetic fields ( i. e., superconductors )? while the best capacitors today store 20 times less energy than an equal mass of lithium - ion batteries, one company, eestor, claims a new capacitor capable of 1 mega - joule per kilogram. whether or not this claim proves valid, it ' s within about a factor of 2 of the physical limit based on the bandgap of the dielectric material. electromagnets of high - temperature superconductors could in theory reach about 4 mega - joules per liter similar to our theoretical batteries given a reasonable density ; existing magnetic energy storage systems top out around 0. 01 mega - joules per kilogram, about equal to existing capacitors. here again, both the realized technology and its ultimate physical potential are far behind the energy density of common hydrocarbon fuels. that brings us to the option of storing chemical potential energy as fuel that can be oxidized by atmospheric oxygen. we do it today, but with two differences : we generate this fuel renewably and convert it to work more efficiently than in combustion engines, either by fuel cells or air batteries. zinc air batteries, which involve the oxidation of zinc metal to zinc hydroxide, could reach about 1. 3 mega - joules per kilogram. but if we take elemental zinc all the way to zinc oxide, then we can theoretically beat the best imagined batteries at about 5. 3 mega - joules per kilogram. zinc has proved interesting enough that several writers ( not us ) have imagined a " zinc economy. " to get really ambitious, we imagine storing energy as elemental aluminum or elemental lithium. those two highly electro - positive elements yield a theoretical energy density - - when oxidized in air - - of 32 and 43 mega - joules per kilogram. at least now the theoretical limit is between 60 percent and 80 percent to that of hydrocarbons ; we just have to figure out how to extract a large fraction of the energy from that oxidation. a more promising approach is to use fuel cells with liquid and gaseous fuels.


| a microscopic double - slit experiment | two centuries ago, thomas young performed the classic demonstration of the wave nature of light. he placed a screen with two tiny slits in front of a single light source, effectively converting it into a two - centered source. on a second screen far away, he saw a pattern of light and dark diffraction fringes, a well - known hallmark of wave interference. along with later studies using particles instead of light, the experiment played a crucial role in establishing the validity of wave – particle duality, a puzzling concept that has ultimately become central to the interpretation of complementarity in quantum mechnanics. in a new twist on this classic experiment, the double slit ( with light waves ) has been replaced by a diatomic molecule ( with electron waves ). at als beamline 10. 0. 1, researchers have shown that diatomic molecules can serve as two - center emitters of electron waves and that traces of electron - wave interference can be directly observed in precise measurements of vibrationally resolved photoionization spectra. in the 1960s, howard cohen and ugo fano conjectured that it should be possible to conduct a microscopic version of the double - slit experiment by photoionizing homonuclear ( single - element ) diatomic molecules. the emitted electrons, which are initially shared between the two indistinguishable atoms, would be " coherent " when their debroglie wavelengths are comparable to the molecule ' s equilibrium interatomic distance. under these conditions, cohen and fano predicted that electron - wave interference should affect the molecule ' s photoionization cross sections ( i. e., the probability of ionization ) for photoionization energies of a few hundred evs ( the extreme ultraviolet regime ). the manifestations of this matter - wave interference have been actively sought in beautiful but time - consuming experiments that require " fixing in space " the molecular targets via complex detection schemes. in addition to the practical difficulties, such an approach required the introduction of arbitrary calibration parameters or fitting functions, leading to equivocal interpretations. the work reported here takes another, more direct approach based on an elaborate, first - principles framework developed within the international group led by f. martin ( autonomous university of madrid ). the analysis includes consideration of the vibrational transitions associated with valence - shell photoionization of diatomic molecules. one striking prediction was that values of the photoionization cross - section would oscillate around a value predicted by


). the analysis includes consideration of the vibrational transitions associated with valence - shell photoionization of diatomic molecules. one striking prediction was that values of the photoionization cross - section would oscillate around a value predicted by the franck – condon principle, which governs the likelihood of transitions involving electronic and vibrational states ( " vibronic " transitions ). the approach was made experimentally possible by the advent of high - brightness, third - generation light sources as well as significant progress in electron detection techniques able to distinguish the various vibrational states available to diatomic molecules. the unique characteristics of extreme beam stability, powerful photon flux, and high resolving power offered at als beamline 10. 0. 1 allowed the research team to access the underlying structure of the valence photoelectron bands and to reliably extract vibrational cross - sections over a wide photon energy range ( 20 to 300 ev ). the experiments were performed on hydrogen ( h2 ) — the simplest of all diatomics, homonuclear nitrogen ( n2 ), and even the heteronuclear carbon monoxide ( co ). clear oscillations around the franck – condon values have been observed and interpreted as the distinct mark of young ' s interferences. they are satisfactorily reproduced by first - principles calculations that do not require the introduction of any external arbitrary parameters or fitting functions. these results on benchmark molecules constitute an important step toward extending this particular combination of detection technique and advanced modeling into a widely applicable structural tool for electron interferometry and holography by capitalizing on coherent photoemission. these multicenter interferences in the continuum are a very sensitive probe of electronic and geometric degrees of freedom. as such, they can track in real time the various couplings at play during the photoionization processes triggered by accelerator - or lab - based light sources that are rapidly developing around the world. research conducted by : s. e. canton ( lund university, sweden ), e. plesiat ( autonomous university of madrid, spain ), j. d. bozek ( slac national accelerator laboratory ), b. s. rude ( als ), p. decleva ( university of trieste and the national research council, institute of materials, italy ), and f. martin ( autonomous university of madrid and the madrid institute for advanced studies in nanoscience, spain ). research funding : ministry of science and innovation ( spain ) and


graphene is a sheet of carbon, just one atom thick, which is electrically sensitive to mechanical deformation and contact with water. not only this, but it is highly effective at repelling water too. it ’ s also far cheaper to obtain than indium, which is used in indium tin oxide ( ito ) for current capacitive touch screen technology. therefore there is a benefit to the environment too, by reducing the demand for industrial mining operations. as explained in our other feature about nokia ’ s nano - tech, graphene is a structure made from carbon atoms bonded together in a planar hexagonal pattern. by definition, sheets of graphene are only one atom thick, but have amazing properties. at nokia world 2011, we found a customised nokia 700, whose screen had been given the hydrophobic coating. we were told that the graphene layer is 97 % transparent. indeed, the screen looked just as crisp as an ordinary 700. this is an improvement over current ito technology which is 90 % transparent. a nokia 700 sporting a hydrophobic coating we were told that the coating was made up of a grid of graphene tubes ( i. e. carbon nanotubes ). each line of the grid was made up of multiple nanotube strands, putting their width on the order of micrometers. however, the structure is still only one tube thick, keeping it on the nanometer scale. we were also told that the graphene layer is thinner than the current ito layers, which accounts for the increased transparency. the width of the grid lines are similar to a human hair, and therefore should just be visible to the naked eye. indeed, part of the demonstration apparatus we saw had a sample piece of polymer with a nanotube grid overlaid, on which we could just about see the grid lines. because water cannot interact with graphene, it makes for an ideal water resistant coating. therefore, entire phone bodies could be covered in graphene to make them more resilient in wet environments. the advantage of graphene doesn ’ t stop there though. the nanotube grid can be mounted to the phone screen with a microscopic air gap. this configuration then acts as a capacitor, with an air dielectric. as droplets of water touch the graphene layer, the capacitance of the air gap is changed, which can be easily detected and read as input. the demonstration set up : high speed camera, linked to nokia 700 with hydrophobic touch layer, and hydrophobic coated polymer sheet


##ene layer, the capacitance of the air gap is changed, which can be easily detected and read as input. the demonstration set up : high speed camera, linked to nokia 700 with hydrophobic touch layer, and hydrophobic coated polymer sheet as a demonstration of both the water resistant ( hydrophobic ) and electrostatic properties of this coating, the nokia 700 was used to a trigger a high speed camera. the phone was fixed at an angle above the polymer sheet, and when the demonstrator dropped water on the phone, it activated the camera and ran straight off the screen. high speed video was then captured of the water droplet falling on to the hydrophobic coated polymer. the video recording was played back to us, and we could see the droplet hitting the polymer in slow motion. on impact, the droplet spread out under its own momentum. however, because it couldn ’ t mix with the graphene, the surface tension of the water pulled it back into a spherical shape. the droplet effectively maintained that shape due to the repulsive forces of the graphene layer. droplet supported by surface tension on a hydrophobic coated piece of polymer this technology has the potential to provide a new form of capacitive touch screen, while making mobile phones more robust. however, nokia still needs to adapt the material so that it reacts to the oils in human skin, instead of water, but still be hydrophobic. another benefit of graphene capacitive technology is that it ’ s far cheaper to produce than current capacitive touch screens. the indium in ito is becoming increasingly scarce and expensive. meanwhile, graphene is just an allotrope of carbon and will be far cheaper to obtain, with less polluting byproducts. david gilson ( and photos by steve litchfield ), 08 november 2011


on the emotional scaffolding of the self, or how the dynamics of temperament fluctuate with social context. we ’ ve previously explored what it means to be human and what defines a “ person. ” much of our understanding of personhood hinges on what we call “ character ” — but what, exactly, is it? here is an omnibus of definitions and insights from notable cross - disciplinary thinkers, from philosophy to neuroscience to literature, underpinning which is a shared sentiment that “ character ” is fluid and responsive to context, rather than a static and unflinching set of traits. a person ’ s authentic nature is a series of shifting, variegated planes that establish themselves as he relates to different people ; it is created by and appears within the framework of his interpersonal relationships. biological anthropologist helen fisher in this will make you smarter : new scientific concepts to improve your thinking : personality is composed of two fundamentally different types of traits : those of ‘ character ; ’ and those of ‘ temperament. ’ your character traits stem from your experiences. your childhood games ; your family ’ s interests and values ; how people in your community express love and hate ; what relatives and friends regard as courteous or perilous ; how those around you worship ; what they sing ; when they laugh ; how they make a living and relax : innumerable cultural forces build your unique set of character traits. the balance of your personality is your temperament, all the biologically based tendencies that contribute to your consistent patterns of feeling, thinking and behaving. as spanish philosopher, jose ortega y gasset, put it, ‘ i am, plus my circumstances. ’ temperament is the ‘ i am, ’ the foundation of who you are. psychologists thomas lewis, fari amini, and richard lannon in a general theory of love : an infant ’ s emotional scaffold provides for temperament and for innate abilities like reading facial expressions. limbic contact with his parents hones that pluripotential structure into the template of emotional life — the neural core of emotional identity. once this quintessence is firm, we say that a person exists, and we can know the individuated attributes of his emotional self. ongoing experience gradually transforms his neural configuration, changing him from who he was into who he is, one synapse at a time. emotional identity drifts over a lifetime — if fast and far enough, one might encounter a stranger ’ s heart where a friend ’ s or a lover ’ s once dwelt.


scie108 discoveries in chemistry : a history department of science, technology, engineering & mathematics : science course number and titlescie108 discoveries in chemistry : a history number of credits3 credits minimum number of instructional minutes per semester2250 other pertinent informationnon - lab course catalog course descriptionthis course examines the historical development of chemistry ; the personalities, stories, and experiments behind modern understanding of matter ( specifically elements and compounds ), and how that understanding has led to practical technologies. in addition, the course explores the nature of scientific thought related to the historic chemical research explored. required course content and direction learning goals : discoveries in chemistry : a history is designed to serve as a one - semester course to meet the science core requirement for the non - science major. discoveries in chemistry : a history covers selected areas of chemistry in a qualitative manner, but not in as much detail as general chemistry for science majors. discoveries in chemistry : a history also illustrates the nature of science by exploring historically important chemical experiments, and how our understanding of the atomic - molecular world was developed from the results of those experiments. this helps the students understand how science works, equipping them to understand and develop informed opinions related to contemporary scientific issues. as one of the natural sciences, chemistry has evolved out of careful observation and experimentation ; as technology evolves, so does the body of chemical knowledge. this course integrates relevant technological advances to illustrate that the methods and practices that allowed chemical knowledge to grow and develop in the past continue to alter and refine our understanding of the physical world. all of these topics are explored from a historical perspective, with examination of the experiments and observations that led to our modern understanding of them. the twofold goal of this approach is to reinforce understanding of the concepts themselves and to illustrate the nature of scientific thought and practice. in addition, historical investigation of scientific developments illustrates how considerations in the wider world — such as social, economic, and cultural factors — affect the course of scientific investigations ; how such concerns affect how scientists think, the scientific issues scientists choose to investigate, questions scientists ask, how scientists interpret experimental results and observations, and how scientists develop frameworks for organizing their understanding of the physical world. conversely, the affects of scientific developments on the outside world, its affects on economics, history, society, culture, etc. are explored. - course students will : - demonstrate an understanding of how observations and experimental evidence shape scientific knowledge, and draw a logical conclusion ; - demonstrate basic understanding of the atomic - molecular nature of matter,


, history, society, culture, etc. are explored. - course students will : - demonstrate an understanding of how observations and experimental evidence shape scientific knowledge, and draw a logical conclusion ; - demonstrate basic understanding of the atomic - molecular nature of matter, and how atoms and molecules give rise to macroscopically - observable elements and compounds ; - describe how historical, economic, social, and cultural factors affect the practice of science and the development of scientific ideas, and how science in turn has affected history, economics, society, and culture ; - evaluate scientific evidence in current scientific issues, and shape and express informed opinions on relevant contemporary scientific issues, and defend their opinions on the basis of evidence ; and - define the role of chemistry in relevant modern technologies. - core ( if applicable ) category i : - apply the scientific method by explaining and identifying its components in a variety of situations. - understand and express the meaning and significance of a variety of communications ( interpretation ). mathematics or sciencestudents will be able to : critical thinking / problem solvingstudents will be able to : planned sequence of topics and / or learning activities : - scientific thought : forming and refining ideas with experimental and observational evidence - phlogiston theory develops to explain apparent loss of mass during combustion - priestly discovers oxygen through decomposition of hgo - lavoisier shows combustion products actually have more mass - combustion - as - oxidation replaces phlogiston theory - in the process, lavoisier distinguishes “ compounds ” from “ simple substances ” - atoms : how we know they ’ re real - lavoisier defines compounds and simple substances, but offers no explanation - davy discovers several oxides of nitrogen - dalton notices mathematical relationships among proportions - the law of definite proportions - dalton proposes atoms as an explanation - also explains compounds and simple substances - development of atomic theory after dalton - gay - lussac ’ s law of combining volumes bolsters atomic theory - avogadro explains discrepancies in theory, but is ignored for fifty years - still resistance among some chemists - this was because atoms were not observable - atomic theory was useful, leading to fruitful research, which swayed some ; but even skeptics used the theory - early 1900s : perrin observes brownian motion, providing direct evidence of atoms - today : atomic force microscopy - inside the atom - dalton ’ s atoms were immutable until j. j. thomson discovered the electron - rutherford discovers the nucleus, moseley defines atomic number - chadwick discovers neutrons -


evidence of atoms - today : atomic force microscopy - inside the atom - dalton ’ s atoms were immutable until j. j. thomson discovered the electron - rutherford discovers the nucleus, moseley defines atomic number - chadwick discovers neutrons - meitner, hahn, and strassmann discover fission - hans bethe determines fusion powers the sun - organizing the elements - lavoisier ’ s “ simple substances ” - dalton ’ s atoms explain the existence of elements - early attempts at organization fail - development of the modern periodic table - cannizzaro ’ s reports more accurate atomic mass values in 1861 - refined atomic mass values allow periodic trends to become clearer to mendeleyev and to meyer : both develop periodic tables - meyer and mendeleyev both make periodic tables for use in textbooks - both developed table to make learning element properties easier - mendeleyev uses periodic table to predict discovery of new elements - de boisbaudran discovers gallium - nilson discovers scandium - winkler discovers germanium - these discoveries bring recognition for mendeleyev, but also priority dispute with meyer - refinements to periodic table - ramsey discovers noble gases - mendeleyev rejects them at first - ramsey shows noble gases to be a new column on the periodic table - discovery of electron explains periodicity - mendeleyev rejects electrons - electrons meant the elements were not the most fundamental form of matter - protons explain te and i discrepancy - structure makes the substance - wohler and von liebig discover isomerism - the development of structural concepts in chemistry - kekule and couper lay down basics of organic structure, explaining isomerism - pasteur discovers chirality - van ’ t hoff uses lack of isomerism in ch2cl2 to propose tetrahedral carbon - how are atoms joined in structures? - kossel proposes ionic bonding - lewis proposes covalent bonding > / li > - lonsdale determines benzene bonds are equal in length - pauling proposes resonance on the basis of lonsdale ’ s results - epilogue : hodgkin wins nobel prize for vitamin b12 and other structural determinations - reproducing natural structures - wohler synthesizes urea - the vital hypothesis - wohler ’ s urea began the overturning of this hypothesis - percy julian synthesizes physostigmine - designing new molecules - hoffmann and eichengrun synthesize aspirin : modifying natural structures - salicylic acid exists


s urea began the overturning of this hypothesis - percy julian synthesizes physostigmine - designing new molecules - hoffmann and eichengrun synthesize aspirin : modifying natural structures - salicylic acid exists in nature, but harsh - structural modification produces aspirin - nazis erase eichengrun from aspirin story - carothers invents nylon - staudinger puts forth macromolecular theory to explain natural and synthetic polymers - carothers uses theory to invent nylon - nylon is structurally similar to silk : biomimetics - macromolecular theory prevailed because it produced useful ( and profitable ) products more so than because of the results of any single decisive experiment - elion and hitchings first use rational design to produce chemotherapy drugs ; win nobel prize - understand the nature of scientific knowledge as being based on evidence and observation - understand the nature of scientific knowledge as being testable - examine scientific evidence and draw conclusions based on that evidence - understand that scientific ideas are refined as new evidence emerges, and to be able to recognize moments in history when such revision occurs, and to be able to recognize contemporary changes in scientific understanding when they occur - recognize simple mathematical relationships in scientific observations and be able to draw conclusions from mathematical relationships - grasp the distinction between descriptive scientific laws and explanatory scientific theories - know the evidence that has led us to the basic theories underlying modern chemistry - understand how protons, neutrons, and electrons combine to form the different kinds of atoms that make up all the elements that make up ordinary matter - grasp that periodic relationships among elements arise from mathematical relationships between the numbers of protons and electrons found in various elements - understand the difference between elements and compounds - understand the nature of ionic bonding and covalent bonding in a cursory manner - understand how atoms join to form molecules ( and extended crystals ) and that the nature of these structures gives rise to the macroscopic properties of a substance - understand the concept of chirality in a cursory manner - understand that it is the molecular - level structure of a substance that gives rise to its properties, and not its origin ( i. e. natural vs. synthetic ) - understand that natural substances can be duplicated by synthesizing the same molecular - level structures artificially - grasp the concept of biomimetics in molecular design - understand that chemists can design and prepare new materials with desired properties by understanding how molecular - level structure affects macroscopic properties - understand the macromolecular nature


- level structures artificially - grasp the concept of biomimetics in molecular design - understand that chemists can design and prepare new materials with desired properties by understanding how molecular - level structure affects macroscopic properties - understand the macromolecular nature of polymeric materials - understand in a cursory manner the processes of nuclear fission and nuclear fusion assessment methods for core learning goals : - course course learning goals are continuously assessed by : periodic written examinations and quizzes, in - class group work and discussions, and writing assignments. - core ( if applicable ) - category i : mathematics or science - category iii : critical thinking / problem solving written examinations and classroom exercises are used to assess the ability of the student to accurately translate descriptive problems into mathematical formulas and solve them. for example, students are asked to calculate relative atomic masses based on the proportions of elements in a series of compounds. students apply the scientific method in the classroom and are required to discuss observations, and give a reasonable explanation to any changes or deviations from the expected results. critical thinking and problem solving are assessed using written examinations and classroom exercises. the classroom exercises contain components aimed at evaluating application of skills, integration of knowledge to explain phenomena, and reasoning exercises. for example, students are asked to evaluate the merit of competing theories in explaining observations made during historic chemical investigations. reference, resource, or learning materials to be used by students : see course format. the students use approved text, demonstration equipment, the library, science learning center, and computer programs. teaching methods employedsection viii is not being used in new and revised syllabi as of 12 / 10 / 08. revision / approval date : approved 5 / 2012