Carbon accounting

In thin sections natural graphite is translucent, strongly pleochroic, and uniaxial. It has a negative sign of birefringence and two extinctions per revolution under crossed Nicol prisms. The atomic number of carbon accounts for its low absorption coefficient for x-rays and electrons. 

Radiolytic ethylene destruction occurs with a yield of ca. 20 molecules consumed/100 e.v. (36, 48). Products containing up to six carbons account for ca. 60% of that amount, and can be ascribed to free radical reactions, molecular detachments, and low order ion-molecule reactions (32). This leaves only eight molecules/100 e.v. which may have formed ethylene polymer, corresponding to a chain length of only 2.1 molecules/ ion. Even if we assumed that ethylene destruction were entirely the result of ionic polymerization, only about five ethylene molecules would be involved per ion pair. The absence of ionic polymerization can also be demonstrated by the results of the gamma ray initiated polymerization of ethylene, whose kinetics can be completely explained on the basis of conventional free radical reactions and known rate constants for these processes (32). An increase above the expected rates occurs only at pressures in excess of ca. 20 atmospheres (10). The virtual absence of ionic polymerization can be regarded as one of the most surprising aspects of the radiation chemistry of ethylene. 

Carbon accounts for only 0.08% of our planet s mass. Nevertheless, life on Earth is based on carbon. Living organisms take in carbon, process it through biochemical reactions, and expel it as waste. 

Carbon-12 ( gC, or carbon with six protons and six neutrons) is boring old run-of-the-mill carbon, accounting for 99 percent of all the Ccirbon out there. 

The distribution of carbon in the form of aromatic, hydroaromatic, and methyl carbon (as assessed in the present work) is presented in Table VIII. The sum of the three forms of carbon accounts for about 97.5-98.09f of the total carbon in lower rank bituminous coal (C < 86% carbon, dmf basis) and about 99.4% of the total carbon in case of the highest rank bituminous coal (C = 90.4%) studied. Small proportions of carboxyl groups are present in lower rank bituminous coal, and if this carbon is taken into account, it may bring the total up to 98% at the maximum. 

The yield and selectivity of a particular product were defined as mole percentage yield and selectivity on a carbon-accounted-for basis. As for the yield of "other acid", the yield was calculated basing on the asumption that the acid was acetic acid or maleic anhydride, because the main acids, besides benzoic acid, were found to be acetic acid and maleic anhydride. The contact time was defined as (volume of catalyst used [ml])/(total flow rate [ml/s]). 

Compound A (4 multiple bonds and/or rings) must be symmetrical because it exhibits only six peaks in its 13C NMR spectrum. Saturated carbons account for two of these peaks (S = 15, 28 ppm), and unsaturated carbons account for the other four (S = 119, 129, 131, 143 ppm). 

Carbon Acidity of Strained Hydrocarbons The difference in the formal hybridization at carbon accounts for the relative acidities of alkanes versus alkenes versus akynes. The greater the s-character of the carbon of Ihe C-H bond of interest, the more acidic is that proton. Of interest here is extension of this idea to strained compounds, which may employ greater or lesser s-character to accommodate the unusual geometries. Will these compounds have acidities that reflect their hybridization Are strained hydrocarbons more acidic than their unstrained analogs ... 

We prepared two carbons by pyrolysis of saccharose followed by heat treatment at two different temperatures 400 C (CS400) and 1000"C (CSIOOO). We performed X-ray diffraction and SAXS on each of these porous materials and obtained the structure factors, S q), following the procedure described by Franklin [14]. The resulting S(q) s are shown in Figure 1 (bold line). We performed Hg porosimetry to obtain the density of both carbons, accounting for the volume occupied by C atoms, closed pores and smaller open pores. We also measured the H/C and the O/C ratios by combustion experiments. The results are summarized in Table 1. 

How can the difference in number of valence electrons between nitrogen and carbon account for the fact that the boiling point of ammonia, NH3, is 130°C higher than that of methane, CH4. 

What characteristic of carbon accounts for the huge variety of organic compounds (22.1)... 

Quantitywise, natural fillers dominate with ca. 70 to 80% by weight of the total consumption, calcium carbonate accounting for the largest share. 

Solvay is Belgium s largest chemical company. Soda ash (sodium carbonate) accounts for a large percentage of its sales, however, the firm has also produced agricultural chemicals, halogen compounds, peroxides, and plastics. Solvay is in fifteenth position in world chemical sales at 9.1 billion (Table 9.22). Belgium had seven new CPI projects under construction as of early 1999 [8]. 

In 2000 at the Netherlands, global warming talks broke down over carbon accounting. The United States wished to use its forest area to offsetting some carbon emissions. 

Spectroscopic evidence suggests that the rings are made primarily of water ice. Some scientists believe that the ice may be covered by a thin layer of carbon, accounting for their very low albedo. Interestingly enough, pairs of "shepherd moons," like those observed above Saturn, have also been observed in the Uranian ring system. After the discovery of the Saturnian shepherd moons, researchers... 

Most of the DOC in the ocean appears to be of marine origin, with terrestrial organic carbon accounting for only 1% of the total annual production [4]. Stable carbon isotope (fi C) ratios of marine DOC are in the range -20 to -33 ppt [25,26], very similar to the ratios measured for marine phytoplankton... 

Economic Aspects. The calcium carbonates (calcites, chalks, limestone powders, dolomites, precipitated calcium carbonates, and surface-treated carbonates) account for 80-90 % of the extenders used in Western Europe. In the Federal Republic of Germany calcium carbonates are more predominant than in the remainder of Western Europe (ca. 90%) calcites with a high degree of whiteness and a mean particle size of 2-5 pm are most widely used. Next follow talc, kaolins (with calcined kaolins), silica, barytes, and mica. 

There are a number of free radicals that exist as isolable and relatively stable chemical entities. Those that contain only carbon and hydrogen are all rather large molecules in which the unpaired electron can be delocalized over a number of carbon atoms. Entries 1 and 2 in Scheme 12.1 are examples of this type. Entry 3 is interesting. It is a saturated molecule and yet surprisingly stable. The extreme steric hindrance of the radical carbon accounts for its appreciable lifetime. 

In the NMR spectrum, the tetra-substituted olefinic carbon gives rise to the peaks from 130 to 140 ppm. The tri-substituted olefinic carbon accounts for the peaks from 118 to 128 ppm, and the aliphatic methyl carbon results in peaks from 20 to 25 ppm. This latter set of peaks can be used to distinguish c/s-l,4-polyisoprene from trans-, 4- and... 

Water-soluble scales and calcium carbonate account for many evaporator scaling problems. Calcium scales have a much greater impact on evaporator capacity and pose the more serious problem. The rate of calcium scaling is very dependent on temperature and is also directly proportional to solids content. Calcium scales can be controlled by minimizing calcium inputs and, to a great extent, through operation techniques. Special treatments are also sometimes effective. 

Measurement to Model. New Wrrk Springer, 2009. Presents a modem and detailed review of methods for forest growth and yield calculations, including comparisons with ecological modeling. Provides for carbon accounting. Builds from basics to the professional level. 

Displacement on carbon. Account for the fact that (CHslgCBr reacts with very dilute OH in CH3OH to give (CHalsCOCHs and not (CHa)sCOH. 

Calcium carbonate accounts for about 65% of total filler consumption in plastics with an annual world-wide usage of about six million tonnes. It is also the most widely used filler in terms of number of applications. The cheapest grades are low in price and are used primarily to reduce costs. By contrast, the finest grades are an order of magnitude higher in price and are used to modify various properties, both during processing and of the final compounds. 

---