Carbon utilization

The overwhelming majority of carbon utilized in nuclear reactors is in the form of graphite for the neutron moderator and reflector. However, several other applications of carbon are noteworthy, and are briefly discussed here. 

Assume the product distribution is known and fixed. Then all products can be lumped into a single, equivalent product, P, which is stoichiometrically linked to the substrate. On a mass basis, carbon from the substrate must match the carbon that appears as product plus the carbon utilized in making biomass. When there is no change in the cell mass. 

The bromonium ion of propene (II), which has a secondary carbon, utilizes some electron density from the bromine (as indicated by the moderate extent of yellow near the bromine)... 

In this paper we look at a novel chemical route that theoretically shows significantly improved carbon utilization in a CTL process. We look at the target C02 emissions and thus the potential for reduction of C02 emissions from such a CTL process. We also look at the implications for the FT chemistry and the opportunities and potential problems for implementing this chemistry. 

The diversity of functions within a microbial population is important for the multiple functions of a soil. The functional diversity of microbial communities has been found to be very sensitive to environmental changes (Zak et al. 1994 Kandeler et al. 1996,1999). However, the methods used mainly indicate the potential in vitro functionality. Functional diversity of microbial populations in soil may be determined by either expression of different enzymes (carbon utilization patterns, extracellular enzyme patterns) or diversity of nucleic acids (mRNA, rRNA) within cells, the latter also reflecting the specific enzymatic processes operating in the cells. Indicators of functional diversity are also indicators of microbial activity and thereby integrate diversity and function. 

In simple conjugated hydrocarbons, carbon utilizes sp2 hybrid orbitals to form a-bonds and the pure px orbital to give the it-MOs. Since the c-skeleton of the hydrocarbon is perpendicular to the wave functions of it-MO, only px AOs need be considered for the formation of it-MOs of interest for photochemists. Let us consider the case of butadiene with px AO contributed by 4 carbon atoms. The possible combinations are given in Figure 2.18. The energy increases with the number of nodes so that Et < < E3 < Et. 

There was always an induction period of 10 to 20 min before the benzene product reached its steady-state rate of production as detected by the mass spectrometer after the introduction of cyclohexane onto the crystal surface. This is shown in Fig. 22 for several catalyst temperatures. The catalyst was initially at 300 K. When steady-state reaction rates were obtained, the catalyst temperature was rapidly increased (in approximately 30 sec) to 423 K and the reaction rate monitored. This was repeated with heating to 573 and 723 K. The benzene desorbed during rapid heating of the catalyst surface is approximately 1 x 1013 molecules or less and represents only a small fraction of the carbon on the surface. The steady-state reaction rates at a given temperature are the same whether the catalyst was initially at that temperature or another. This induction period coincides with a higher than steady-state uptake of cyclohexane. A mass balance calculation on carbon, utilizing the known... 

While the high proportion of the mineral calcium in dairy products has been hypothesized as the factor contributing to favorable metabolic outcomes (Zemel, 2001), several studies have identified more favorable health outcomes in intervention trials whereby calcium is administered in the form of dairy products in contrast to supplementation (Zemel, 2004, 2008). It may be that the calcium phosphate found in dairy products exerts a more significant weight loss effect as opposed to the calcium citrate or calcium carbonate utilized in supplements (Lorenzen et al., 2006). 

In general, the design objective is to determine the most cost-effective remedial design. The cost functions for pump-and-treat remediation using granular activated carbon (GAC) derived by Culver and Shenk (1998) were adapted for this analysis. In addition to the operating costs and the treatment capital costs considered by Culver and Shenk (1998), the capital costs of well installation have also been included, and the carbon utilization costs are calculated at every simulation time step. Thus the objective function can be described as follows ... 

Connolly, J. P., R. B. Coffin, and R. E. Landeck. 1992. Modeling carbon utilization by bacteria in natural water systems. In Modeling the Metabolic and Physiologic Activities of Microorganisms (C. J. Hurst, Ed.), pp. 249-276. 

Electron microscopic examination of catalyst materials, particularly those containing natural components, permits the identification of their origin. For example, carbons utilized as supports for precious metals in a wide variety of slurry-phase and fixed-bed reactions can be derived from a large number of naturally occurring sources (Fig. 8). The shape, morphology, and composition are useful properties for determining their origin. 

It was first produced in the early 1960s by The General Electric Company, UK, by using cellulose as a substrate. Present techniques of preparation of glassy carbon utilize such organic substrates as phenolic resins and involve controlled pyrolysis in inert atmosphere at temperatures ranging between 1000 and 3000 °C. 

Heinonsalo, J., Jorgensen, K. S. Sen, R. (2001). Microcosm-based analyses of Scots pine seedling growth, ectomycorrhizal fungal community structure and bacterial carbon utilization profiles in boreal forest humus and underlying illuvial mineral horizons. ELMS Microbiology Ecology, 36, 73-84. 

Arrhenius parameters (as far as available) for the ring-opening reactions of ethylene oxide, propylene oxide, and isobutylene oxide. Overall values of ftCi and fcHcl obtained for propylene oxide have been split into rate coefficients for attack at primary carbon and attack at secondary carbon, utilizing gas chromatographic product analysis data [152]. (It is interesting to note that the results for attack at primary carbon are of the same order of magnitude as the corresponding values for ethylene oxide.) First-order rate coefficients at a constant acid concentration for the acid catalyzed hydrolysis of various epoxides [153] are collected in Table 10. Rate coefficients of the uncatalyzed and acid catalyzed reactions of ethylene oxide with various nucleophiles [151, 154] can be found in Table 11. 

Goldman, J. C., and Dennett, M. R. (1991). Ammonium regeneration and carbon utilization by marine bacteria grown on mixed substrates. Mar. Biol. 109, 369—378. 

Ratios between O2 consumption and inorganic carbon and nutrients regeneration, called the remineralization ratios, provide useful insights into biogeochemical cycles in the oceans (e.g., export of material to the deep sea and depth-dependent preferential regeneration, if any, of one constituent over the others). For the Indian Ocean, these ratios have been derived from observed variations in concentrations of O2, nutrients and inorganic carbon. Utilizing linear relationships between NOs and... 

Additional in-stream processes can affect the fi G of DIG (Figure 10). Assimilation of DIG by aquatic organisms through photosynthesis produces organic material with a fi G 30%o lower than the carbon utilized (Rau, 1979 Mook and Tan, 1991), resulting in an increase in the fi G of the remaining DIG. Dissolution of carbonate minerals in-stream will also tend to increase the 6 G of DIG. In contrast, precipitation of calcite will cause a decrease in the fi G of the remaining DIG, due to the equilibrium fractionation between calcite and DIG of 2%o. 

S. Mitsuhashi, N. Kurano, S. Harayama and S. Miyachi, Third International Symposium on Inorganic Carbon Utilization by Aquatic Photosynthetic Organisms, Vancouver (1997). 

Activated carbon utilized for gas purification, e.g. for the adsorption of solvent vapor, can be regenerated by desorption with steam at 120 to 140°C. The activated carbon then has to be dried. In special cases other types of regeneration are possible. 

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