E-CCM

FIGURE 3.28 Cross-sectional SEM images of MEAs prepared by conventional, catalyst-coated membrane (CCM), and CCM hot-pressed methods, taken before and after long-term operation, (a) Conventional—fresh, (b) Conventional—1000 h, (c) CCM—fresh, (d) CCM—1000 h, (e) CCM hot pressed—fresh, and (f) CCM hot pressed—500 h [97]. 

Table V-B-14. Rate coefficients (k = A x e" Ccm molecule s ) for the reaction of OH with 4-methyl-2-pentanone [CH3C(0)CH2CH(CH3)2]...

Figure E.l. If the real (noninteger) number of shells is calculated, the heat exchange profiles Ccm be divided in any way and the sum is always the same, (From Ahmad, Linnhoff, and Smith, Trans. ASME, J. Heat Transfer, 110 304, 1988 reproduced by permission of the American Society of Mechanical Engineers.)...

Atom Contribution Methods, Electrotopological State (E-state) Indices and CCMs... 

Ilk, N. Kosma, P. Puchberger, M. Egelseer, E. M. Mayer, H. F. Sleytr, U. B. Sara, M. Structural and functional analyses of the secondary cell wall polymer of Bacillus sphaericus CCM 2177 that serves as an S-layer-specific anchor. J. Bacterial. 1999,181,7643-7646. 

IC, and the software tool may not have warned you. You should also observe that such software tools often do not consider important external component tolerances. For example, your inductor itself may have a +20% tolerance on its inductance. But 20% lower inductance could mean up to 25% higher peak currents (if you are operating close to the CCM-DCM boundary, though with an r of 0.4, the increase in the peak would only be 0.2 x 0.25, i.e., 5%). Note that 1/0.8 = 1.25, so if L falls 20%, the AC current increases 25%. 

NATO/CCMS (North Atlantic Treaty Organization, Committee on Challenges to Modern Society) (1997). Introduction to the Themes of the Workshop. In Integration of Risk Assessment and Health Impact Assessment. Report of the Twelfth Workshop on Methodology, Focalisation, Evaluation and Scope of Environmental Impact Assessment in Reykjavik, Iceland, May 14-18, 1997. North Atlantic Treaty Organisation, Committee on Challenges to Modem Society (NATO/CCMS) Pilot Study, co-ordinated by E, F. Verheyen, K. Nagels, and M. Coenen, Antwerpen University of Antwerpen, pp. 49-53... 

Fox, D. J. Herakovich, C. T. and Sykes, G. F. The NASA-Virginia Tech Composites Program Interim Report 63, also CCMS 87-11 and VPI-E-87, July 1987. 

Figure 2.15 shows a schematic representation of the CCM manufacturing process. The first step for CCM preparation comprises mixing the reactive layer materials (e.g., platinum-supported carbonblack) with different amounts of PTFE, polymer electrolyte powder (e.g., Nafion), and/or filler materials... 

In closely related experiments it was shown that sp C—H activation takes place reversibly within the coordinahon sphere of the electron-rich Ir(I)-diphosphine complex 58 (Scheme 6.9) to form an alkyl-amino-hydrido derivative 57 reminiscent of the CCM intermediate 24 the solid-state structure of 57 is shown in Figure 6.13 [40]. It appears that C—H activation only takes place after coordination of the amine function to the Ir(I) center (complex 58, NMR characterized). Amine coordination allows to break the chloro bridge of 59 and to augment the electron density of the metal center, thus favoring oxidative addihon of the C—H bond. Most importantly, the microscopic reverse of this C—H activation process (i.e. C—H reductive elimination) models the final step of the CCM cycle (see Scheme 6.1) indeed, the reaction of Scheme 6.10 is cleanly reversible at 373 K. 

The neutral 6 2 3 molar ratio CCM salt is comprised of 23.7% elemental Ca on a dry weight basis. Various states of hydration of the CCM powder will of course yield slightly lower Ca contents and the preparation of an octa-hydrate form of CCM powder (6 2 3 molar ratio) that comprises 20.73% Ca by weight has been described previously (Fox et ah, 1993b). CCM compositions with a higher proportion of citrate and/or malate moieties (e.g., 4 2 3 molar ratio) will contain a proportionally lower Ca content. Table 6.3 lists the Ca content of various Ca salts. 

Ca is a comparatively difficult element for the body to absorb and digest. It is essentially only available for consumption associated with various other moieties (e.g., citrate, phosphate, and other anions). Each Ca source has unique physical, structural, and chemical properties such as mass, density, coordination chemistry, and solubility that are largely determined by the anions associated with the Ca +. Aqueous solubility of various Ca salts can vary markedly and comparisons are frequently made under standardized conditions. The water solubility of CCM is moderate when ranked versus other Ca sources frequently used as dietary supplements and food/beverage fortificants. The solubility of CCM (6 2 3 molar ratio) is 1.10-g salt in 100 ml of H2O at 25 °C (Fox et ah, 1993a). Table 6.4 lists the solubility of various Ca sources in water at specific temperatures, and also includes some information on potential sensory characteristics. 

Ca carbonate is often used in supplement tablets or pills because of the high Ca density and low cost. However, a powdered Ca dietary supplement, intended to be mixed /dissolved into beverages or other fluid foods (e.g., soups and sauces) by the consumer just prior to consumption, is a novel product form applicable only to a soluble Ca salt such as CCM. A powdered Ca supplement would of course avoid the problems some consumers experience with swallowing pills and tablets, as well as eliminate any uncertainty associated with tablet disintegration and dissolution. 

Solid preparations intrinsically labeled prior to precipitation [i.e., CaC03, Ca oxalate (CaC204), TCP, HA, and CCM], spinach and kale grown hydroponically and labeled via a nutrient solution during growth... 

Average Ca intake maintained at 1390 453 mg/day via consumption of Ca-fortified OJ (i.e., one 8-oz glass AM and PM supplying 700 mg Ca/d as CCM) in conjunction widi the following treatments (3-wk each) adhered to in randomized order widi an intervening 2-week washout period ... 

Ca Abs from CCM in OJ during intake of die placebo or with die non-digestible, fermentable oligosaccharide treatments were high despite the fact diat subjects e xceeded the AI recommended for Ca. 

Overall, serum and urinary increment methods have shown that a Ca source (e.g., CaCOs) accompanied by citrate is better absorbed than one that is not (Heaney et ah, 1999). Citrate that is absorbed into circulation is inclined to bind Ca ions and thereby artificially elevate incremental data compared to other salts (Heaney, 2001b). A number of studies utilizing the most sensitive isotopic tracer methods have demonstrated that CCM is highly absorbable compared to other Ca sources (Abrams et ah, 2003 Heaney et ah, 1989b Miller et ah, 1988 Smith et ah, 1987). 

Andon (2003) compared five different CCM formulations covering a threefold range of Ca citrate malate molar ratios from 154 previous studies in humans. Intrinsically labeled tablets or juices comprising 250 mg Ca as CCM were tested in adolescents and groups of women 20 to 30-years and 40 to 77-years old. A comparison of mean values for age groups, molar ratios, and vehicles revealed no differences. Comparison with reported values in the literature, after adjustment to equalize Ca doses and indexing versus a standard (i.e., milk = 100), revealed Ca absorption from CCM consistently exceeded absorption from other sources including milk, various dairy products, fortified foods, and Ca supplements. 

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