Primary production definition

One of the predicted effects of pollutants on eco stems suggested by Woodwell is a reduction in the standing crop of organic matter, which would lead to a reduction in nutrient elements held within the living system. The evidence discussed earlier definitely shows that primary production is much lower in an ozone>stressed conifer-forest ecosystem. This result would be anticipated in all similarly stressed natural ecosystems or agroecosystems. 

Figure 1. Conceptual product definitions of enzyme-based biofuel cells as they are compared in their specific energy and energy density to the existing primary battery technology. Based on Figure 2 of ref 15. Reproduced with permission. Copyright 1999 The Electrochemical Society, Inc.

Figure 1 Juxtaposes the energy fields of these three potential product definitions with that of conventional primary battery technology. The data on the energy densities for the battery product definitions were adopted from a recent technology review. The expected energy performance figures for biofuel cells...

Allylic hydroperoxides are primary products in the autoxidation of - olefins, and lack of definite information on their reactivity and chemical behavior has hampered efforts to understand olefin oxidation mechanisms (2). This deficiency is most strongly felt in determining the relative rates of addition and abstraction mechanisms for acyclic olefins since assignment of secondary reaction products to the correct primary source is required. Whereas generalizations about the effect of structure on the course of hydroperoxide decompositions are helpful, most questions can be answered better by directly isolating the hydroperoxides involved and observing the products formed by decomposition of the pure compounds. 

As can be seen in Figs. 3a and 3b phenol is clearly a primary product on both catalysts. On HY all the other compounds seem to be secondary products except the hydroxyacetophenones which could be formed at least partly as primary products. Compounds III, IV and V are formed only at high conversion. On HZ SMB, hydroxyacetophenones are definitely secondary products while para-acetoxyacetophenone is a primary product. Compounds IV and V are not formed in detectable amounts. Compounds VI and VII are formed in small quantities. 

Rowland, et al. (14) have used radiochemical tracer techniques to study reaction (1) and obtain equal yields of CO and COS. CS oxidation could account for a significant fraction of the atmospheric COS budget ( ) and definitive measurements of the mechanism of reaction (2), its primary products and the routes to, and yields of the ultimate stable products are needed. 

Identification of primary participants. The distinction between primary products or intermediates and those of higher ranks is easy and usually unambiguous. By definition, primary products or intermediates arise directly and exclusively from the original reactant or reactants, initially present at finite concentrations in contrast, products or intermediates of higher ranks arise from participants whose initial concentrations are zero. As a result, the initial formation rates of primary participants are finite, those of participants of higher rank are zero. An examination of the concentration histories allows this distinction to be made. (A participant may appear to be primary although formed in two or more steps, namely, if all but one of these are very fast.)... 

Definitive evidence for vinylcarbene intervention during cyclopropene thermolyses stems from the identification of cyclopropane 202 as a primary product from cyclopropene 200 (equation 69). Product 202 can only come from an intramolecular C-H... 

Pyrolysis is by definition thermal decomposition occurring in the absence of oxygen. It is always also the first step in combustion and gasification processes where it is followed by total or partial oxidation of the primary products. 

By definition, the material balance includes materials entering and leaving a process. Inputs to a process or a unit operation may include raw materials, chemicals, water, air, and energy. Outputs include primary product, byproducts, rejects, wastewater, gaseous wastes, liquid, and solid wastes that need to be stored sent off-site for disposal and reusable or recyclable wastes (Figure 3). In its simplest form, a material balance is drawn up according to the mass conservation principle ... 

MejGa, which is the primary product of the electrode reaction. When EtI or ICHjCHjCN is used instead, no definite Ga compound can be isolated ... 

Absolute rate coefficients and Arrhenius parameters have been obtained for the cycloaddition reaction of S( F2,1,0) atoms with a representative series of olefins and acetylenes. The activation energies are small, and they exhibit a trend with molecular structure which is expected for an electro-philic reagent The A-factors show a definite trend which can be attributed to steric repulsions and a generalized secondary a-isotope effect explained by activated complex theory. Secondary a-H/D kinetic isotope effects have been measured and their origin discussed. Hartree-Fock type MO calculations indicate that the primary product of the S( F) + olefin reaction is a ring-distorted, triplet state thi-irane, with a considerable energy barrier with respect to rotation around the C-C bond. 

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