WHAT IT IS

Another important factor, however, is the fairly new development of digital technology (which will be discussed in a later chapter). This prevents noise (random errors) from creeping into the signal. The two innovations, transistorization and digitization, have made it practical for us to make electronic systems of almost unlimited complexity. As an everyday example, the extremely complex little microprocessors in most new automobiles have improved gas mileage, lowered pollution, and improved the effectiveness of brakes. Of course, the reader knows of many other examples, such as cellular phones, etc. 

The bipolar type of transistor is usually made from the element silicon, which has been doped so it has two junctions, instead of the single junction that was described in the previous chapter on diodes. Bipolar transistors can be of either the PNP or NPN type. 

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For example, energy transfer in molecule-surface collisions is best studied in nom-eactive systems, such as the scattering and trapping of rare-gas atoms or simple molecules at metal surfaces. We follow a similar approach below, discussing the dynamics of the different elementary processes separately. The surface must also be simplified compared to technologically relevant systems. To develop a detailed understanding, we must know exactly what the surface looks like and of what it is composed. This requires the use of surface science tools (section B 1.19-26) to prepare very well-characterized, atomically clean and ordered substrates on which reactions can be studied under ultrahigh vacuum conditions. The most accurate and specific experiments also employ molecular beam teclmiques, discussed in section B2.3. 

The acetylenic proton The carbanion now eliminates Cl to give a most odd-looking carbene. Can you see what it is ... 

In figure 4 is shown how a separatory funnel and a pressure equalized addition funnel are made. The funnel part is just a PP funnel from the grocery store and what it is attached to is a stainless steel ball valve. See how the addition funnel is made by using a rubber stopper and an extra extension of tubing to the top of the funnel Well, that s how one can make a sealed addition funnel out of the ordinary glass separatory funnel that one gets with a distillation kit or from wherever. 

A Citizen s Guide to Radon What It Is and What to Do About It. U.S. Environmental Protection Agency and U.S. Department of Health and Human Services, OPA-8-004. Government Printing Office, Washington, DC, 1986. 

Lang, G.F., The Fourier Transfonn... What It is and What It Does, Informal Nicolet Scientific Corporation Monograph, December 1973. 

A specification should outline to the bidding vendors just what it is you want to accomplish with the equipment and how reliable it must be. Compressor reliability can be achieved if it begins prior to vendor design and fabrication. Therefore, a truly reliable piece of equipment begins in the specification. 

Knowledge of the desired value It is neeessary to know what it is you are trying to eontrol, to what aeeuraey, and over what range of values. This must be expressed in the form of a performanee speeifieation. In the physieal system this information must be eonverted into a form suitable for the eontroller to understand (analogue or digital signal). 

However, these requirements go further than merely controlling the devices used for measurement. They address the measurements themselves, the selection of the devices for measurement and also apply to devices which create product features, if they are used for product verification purposes. If you rely on jigs, tools, fixtures, templates, patterns, etc. to form shapes or other characteristics and have no other means of verifying the shape achieved, these devices become a means of verification. If you use software to control equipment, simulate the environment or operational conditions, or carry out tests and you rely on that software doing what it is supposed to do, without any separate means of checking the result, the quality of such software becomes critical to product verification. In fact the requirements apply to metrology as a whole rather than being limited to the equipment that is used to obtain the measurement and therefore a more appropriate title of the section would be Control of measurements . 

This requirement is similar to that stated in clause 4.11.2 of the standard and addressed later in this chapter. The checks and rechecks required to prove that the software is capable of verifying the acceptability of product are a means of calibrating test software. However, test software does not wear or drift with age or use and so cannot be calibrated against a standard traceable to national standards. To control test software you need to consider what it is that you need to control. As a minimum you should control its use, modification, location (in terms of where it is installed), replication, and disposal. Requirements for other controls are covered in clause 4.11.2 of the standard, where they can be applied to test software. 

The NMR magnetic shielding for atoms like carbon is affected greatly by what it is bonded to and the type of bond to its neighbor. Use the inner carbon atoms of normal butane as the reference atom and calculate the shift in C isotropic shielding for 2-butene and 2-butyne. Can you explain these shifts as a function of the changing molecular environments ... 

These details show that camphor oil must he bought for what it is worth. Ni> deBnite standards cau be laid down, and only a complete analysis will show the value ol a gi veu sample. 

This is a doubtful conclusion since if temperature-vapour tension curves for volatile substances be examined it will be seen that at low temperatures the rate of diminution of the vapour tension falls off rapidly and hence the-vapour tension at — 190° C. is often not vastly different from what it is at normal temperature, and hence is not by any means negligible when we take into account the very small quantity of substance that needs to be inspired in order for its odour to be perceptible. 

Aimstrong, J. H. (1993). The Railroad What It Is, What It Does, 3rd ed. Omaha Simmons-Boardman Books, Inc. Bilz, F., and Hnlger, S. (1998). A Decade of Three-phase Traction Technoogy for Diesel-Electric Locomotives in North America. Translated from ZEV+DET Glassers Aimalen 121(9)71997. Siemens AG Transportation Systems Group. 

In addition to ordinai y matter, scientists have evidence for the existence in the universe of dark matter. Some of the dark matter is ordinai y matter, such as dust in outer space and planets going around other stars. Astronomers cannot see ordinai y dark matter because any light coming from such matter is too faint to be observed in telescopes. However, most of the dark matter in the universe is believed not to be ordinary matter. At the present time it is not known what this mysterious dark matter is, or what it is made of. Scientists know that this dark matter exists because it exerts a gravitational force on stars (which are made of ordinary matter), causing the stars to move faster than they otherwise would. According to present estimates, there is perhaps five times as much dark matter in the universe as ordinary matter. 

Planning for quality requires attention to detail. The goal of quality planning is to assure that the outputs of the project will perform - that it will do what it is supposed to do. The quality plan also establishes the criteria of performance by which the project output will be measured when it is completed. 

Variations in solution composition throughout a test should be monitored and, if appropriate, corrected. Variations may occur as a result of reactions of one or more of the constituents of the solution with the test specimen, the atmosphere or the test vessel. Thus, it is important that the composition of the testing solution is what it is supposed to be. Carefully made-up solutions of pure chemicals may not act in the same way as nominally similar solutions encountered in practice, which may, and usually do, contain other compounds or impurities that may have major effects on corrosion. This applies particularly to artificial sea-water, which is usually less corrosive than natural sea-water. This subject is discussed in detail in a Special Technical Publication of ASTM, and tests with natural, transported and artificial sea-water have been described . Suspected impurities may be added to the pure solutions in appropriate concentrations or, better still, the testing solutions may be taken directly from plant processes whenever this is practical. 

It-from-bit embodies the central notion that every it - that is, every aspect of reality electrons, protons, photons, fields of force, or even the what we call space-time itself - is in the deepest sense a derivative of experimentally deduced answers to yes/no questions that is, to bits. If we allow ourselves for a moment to go back to the roots of what it is that we by convention call reality, we see that it is something that is literally defined by a particular sequence of yes/no responses elicited from either a mechanical or (our own biological) sensory apparatus in other words, reality s origin is fundamentally information-theoretic. 

The cause of the weaker G dependence must be ascribed to some particular feature of geometry, although exactly what it is has not been found. All of the three bundles involved had their rods supported and correctly positioned by wires wrapped helically around certain of the rods, and it is possible that the wires caused an unfavorable distribution of steam and water. However, it is doubtful that the wire wraps were themselves responsible, since several of the bundles conforming to Eq. (28) were also wire wrapped. (Other devices used for rod supports are suitably spaced grids and ferrules.) The explanation most probably lies in a combination of the effects of the wire wraps with the effects of given rod diameters and rod spacings. For ease of identification, the data that conform with Eq. (28) are hereafter called normal data. 

Peyote is ingested fresh (as whole dried buttons) or as powder (loose in capsules or pressed into tablets). Mescaline sold on the street (see Table 6—2) is generally not what it is claimed to be but is most likely one of the following DOM, PCP, LSD, caffeine, or amphetamine-related stimulants (Kulberg... 

A number of different types of HPLC detector have been discussed in the previous chapter. In comparison to these, a mass spectrometer is a relatively expensive detector and there need to be considerable advantages associated with its use to make the significant financial investment worthwhile. What are these advantages In order to answer this question, we must first consider what it is we are trying to achieve when using chromatography ... 

Both of these - the conceptual and the syntactical [philosophical] - are different in different diseiplines. The significance for education of these diverse structures lies preeisely in the extent to whieh we want to teach what it is true and have it understood . 

The Group A emphases are those that inform the development of chemical literacy (DeBoer, 2000) and should be made available to all students (cf scientific literacy - (Roberts, 2007). These emphases all call for an imderstanding of a macro type of representation, so that learners appreciate what it is when they encounter a chemical phenomenon e.g. a solution, a colloid, a precipitate. This understanding would enable students to answer the question what is it and possibly what to do with it how to act when they encounter such a chemical phenomenon. These emphases also call for an understanding of the submicro type of representation, so that learners can qualitatively explain the nature of the macro phenomena that they encounter and hence be able to answer the question why is it as it is In order to explore these emphases, a chemistry curriculum would need to address a variety of contexts related to the three Group A emphases that have mearung in the everyday world. Pilot, Meijer and Bulte (2008) discuss three such contexts ceramic crockery, gluten-free bread and the bullet-proof vest. 

This solvent shell is in the way, holding back the nucleophile from doing what it is supposed to do (go attack something). For the nucleophile to do its job, the nucleophile must first shed this solvent shell. This is always the case when you dissolve a nucleophile in a polar solvent, except when you use a polar aprotic solvent. 

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