How it works

Phosphoric acid (H3PO4) is the only common inorganic acid that has enough thermal stability, chemical, and electrochemical stabihty, and low enough volatihty (above about 150°C) to be considered as an electrolyte for fuel cells. Most importantly, phosphoric acid is tolerant to CO2 in the fuel and oxidant, unlike the alkaline fuel cell. Phosphoric acid was therefore chosen by the American company. United Technologies (later the spin-off 

ONSI Corporation), back in the 1970s as the preferred electrolyte for terrestrial fuel cell power plants. 

The PTFE binds the carbon black particles together to form an integral (but porous) structure, which is supported on a porous carbon paper substrate. The carbon paper serves as a structural support for the electrocatalyst layer, in addition to acting as the current collector. A typical carbon paper used in PAFCs has an initial porosity of about 90%, 

Flat surfaces between catalyst layer and substrate promote better and uniform gas diffusion to the electrode. 

Bipolar plate made from two pieces of porous, ribbed substrate and one sheet of conductive, impermeable material such as carbon. The porous ribbed substrates hold phosphoric acid. 

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Phase diagrams are mostly determined by thermal analysis. We now discuss one-component systems to show how it works. The more complicated diagrams for binary, ternary or quaternary alloys are determined by the same method. 

CR Calladme, HR Drew. Understanding DNA The Molecule and How It Works. New York Academic Press, 1997. 

The reason for an Exposition is so that there is a description of the system showing how it works and how it controls the achievement of quality. This is different from the policies and procedures. The policies are a guide to action and decision and as such are prescriptive. The procedures are the methods to be used to carry out certain tasks and as such are task related. They need to be relatively simple and concise. A car maintenance manual, for example, tells you how to maintain the car but not how the car works. Some requirements, such as those on traceability and identification, cannot be implemented by specific procedures although you can have specific policies covering such topics. There is no sequence of tasks you can perform to achieve traceability and identification. These requirements tend to be implemented as elements of many procedures which when taken as a whole achieve the traceability and identification requirements. In order that you can demonstrate achievement of such requirements and educate your staff, a description of the system rather than a separate procedure would be an advantage. The Exposition can be structured around the requirements of ISO/TS 16949 and other governing standards. It is a guide or reference document and not auditable. 

Create a system manual that describes your quality system and how it works and references all the procedures, standards, etc. that implement your quality policies. 

An inventory management system should be established - meaning set up on a permanent basis to meet defined inventory policies and objectives approved by executive management. It should be documented - meaning that there should be a description of the system, how it works, the assignment of responsibilities, the codification of best practice, procedures, and instructions. The system should be planned, organized, and controlled in order that it achieves its purpose. A person should therefore be appointed with responsibility for the inventory management system and the responsibilities of those who work the system should be defined and documented. Records should be created and maintained that show how order quantities have been calculated in order that the calculations can be verified and repeated if necessary with new data. The records should also provide adequate data for continual improvement initiatives to be effective. 

The molecular HF-Xa method has been reviewed by Connolly, and you might like to see how it works for the H2O example. 

U. S. Geological Suivey. (1998). Water Science for Schools. Hydroelectric Power How it Works. . 

How it Works Typical of This Class of Pump (By permission of [27])... 

One way to separate two cations in water solution is to add an anion that precipitates only one of the cations. This approach is known as selective precipitation. To see how it works, consider a simple case, a solution containing Mg2+ and Na+ ions. Referring back to Table 16.1 (p. 433), you can see that Mg2+ forms a couple of insoluble compounds MgC03 (K = 6.8 X 10-6) and Mg(OH)2 (K = 6 X 10-12). In contrast, all of the common compounds of sodium are soluble, including the carbonate and hydroxide. It follows that you could readily separate Mg2+ from Na+ by adding either C032- or OH- ions to the solution. In either case, Mg2+ will precipitate while Na+ remains in solution. 

As organic chemistry developed, it became apparent that some systematic way of naming compounds was needed. About 70 years ago, the International Union of Pure and Applied Chemistry (IUPAC) devised a system that could be used for all organic compounds. To illustrate this system, we will show how it works with alkanes. 

Chemistry is an important part of what is called science. Since every phase of our daily life is affected by the fruits of scientific activity, we all should know what scientific activity is, what it can do, and how it works. The study of chemistry will help you learn these things. 

I knew nothing of the work of C. G. Vayenas on NEMCA until the early nineties. Then I learned from a paper of his idea (gas interface reactions could be catalyzed electrochemically), which seemed quite marvelous but I did not understand how it worked. 

If the initial concentrations of the raw material were (in moles per liter), [HCNlo = 1, [H2S04]q = 1.5, and [HCHO]q = 2, then the preceding sequence of operations would immediately have violated Constraint-2, since [HCN] = 1 > 0.1. Similarly, Constraint-3 is violated by the preceding sequence, since [HSO4] = 0 < 1.5. In Section III,D, we discuss the notion of demotion of Clobberers. Let us see how it works here and leads to temporal ordering of operations ... 

More detailed information can be obtained by calculating the charge contours by a procedure called the density-functional method. We will not explain how it works... 

National Digestive Diseases Information Clearinghouse. Your digestive system and how it works, National Digestive Diseases Information Clearinghouse Web site. Available online. URL http //digestive.niddk.nih.gov/ddiseases/pubs/yrdd/. Accessed on March 18, 2008. 

If we are to harness the placebo effect and make use of it in clinical practice, we first have to understand how it works. A number of factors have been proposed as explanations of the placebo effect. These include the relationship between doctors and patients, the patient s beliefs and expectations, the production of opiates in the brain, and a phenomenon called classical conditioning, in which people come to associate pills and injections with therapeutic effects, just as Pavlov s dogs came to associate the sound of a bell with the presentation of food. In this chapter we look at how all of these processes combine to produce placebo effects, and we consider their implications for the treatment of depression. 

Kajf Remember that there is an accurate timer in Nenopus embryos that doesn t depend on DNA, RNA, or protein synthesis. It is still a mystery how it works. 

Currently, the only drug on the market that works by blocking the body s absorption of calories is orlistat, which is sold under the brand name Xenical . Orlistat specifically decreases the absorption of fats from food consumed. A further discussion of orlistat and how it works can be found in Chapter 5. 

Dapson RW. Glyoxal fixation how it works and why it only occasionally needs antigen retrieval. Biotech. Histochem. 2007 82 161-166. 

Although the resonant level model successfully explains a few general aspects of chemisorption, it has nevertheless many shortcomings. The model gives no information on the electronic structure of the chemisorption bond it does not tell where the electrons are. Such information is obtained from a more refined model, called the density functional method. We will not explain how it works but merely give the results for the adsorption of Cl and Li on jellium, reported by Lang and Williams [20]. 

Chart paper carriage. This is where the chart paper nestles while you run an IR. If it looks suspiciously like a clipboard, it s because that s how it works. 

The following selection is about the invention of the compact disc, and explains how it works. 

Action includes not only individual programming-language messages or procedure calls but also complete dialogs between objects of all kinds. We can always talk about the effects of an action even without knowing exactly who initiates it or how it works in detail, as in this schedule course example. 

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