CUMULATIVE chemical

CASSI Cumulative (Chemical Abstracts Service Source Index), Chemical Abstracts Service, American Chemical Society, Columbus, Ohio, 1991. 

Roche datasets, (b) Cumulative topological polar surface area (A ) distributions of compounds in the Gasteiger [33] and Roche datasets, (c) Cumulative chemical complexity distributions of compounds in the Gasteiger [33] and Roche datasets, (d) Cumulative rotatable bond count distributions of compounds in the Gasteiger [33] and Roche datasets. 

Because Equation (31.4) is mathematically equivalent to either Equation (31.5) or (31.6) (shown below), the formula for MOEatrazine simazine in Equation (31.4) is of the proper form - namely, a benchmark dose corresponding to a known amount of toxicity, divided by a cumulative dose from exposure that reflects the relative toxicity of the cumulated chemicals. 

The concept of cumulative chemical exergy consumption is very useful and accounts for the fact that when a compound (e.g., ammonia) is introduced into a process, its chemical exergy has to be corrected for the exergy consumption accumulated since this compound was manufactured from its natural constituents (air and natural gas in the case of ammonia). 

The chemical analysis results and the physical observations are stored in a database for further retrieval. The cumulative chemical data are retrieved in the form of tables for inclusion in a regulatory report (Fig. 5) or for... 

A cumulative chemical composite diagram, in which stable-isotope data were plotted, makes it possible to classify the water and to trace the ratios in the mixture. 

Fig. 2. Cumulative chemical composite diagrams, plotting the total concentrations of the major anions and cations and total concentrations of salts in milliequivalents against the stable-isotope content of as (%o) related to SMOW for (A) deep water of the...

Fig. 3. Cumulative chemical composite diagram with mixing of groups A, B and C (cf. Fig. 2), for water of the northeastern Negev.

Our discussion of chemical reactions of alkadienes will be limited to those of conju gated dienes The reactions of isolated dienes are essentially the same as those of individual alkenes The reactions of cumulated dienes are—like their preparation— so specialized that their treatment is better suited to an advanced course m organic chemistry... 

Health and Safety Factors. Like other low molecular weight ketones, MIBK is an anesthetic chemical with no highly cumulative toxicological effects. Inhalation of vapors can irritate mucous membranes. 

Toxic Substances ControlA.ct Chemical Substances Inventory Vol. 3, U.S. Environmental Protection Agency, Washington, D.C., May 1979, Cumulative Suppl., July 1980. 

As with the case of energy input, detergency generally reaches a plateau after a certain wash time as would be expected from a kinetic analysis. In a practical system, each of its numerous components has a different rate constant, hence its rate behavior generally does not exhibit any simple pattern. Many attempts have been made to fit soil removal (50) rates in practical systems to the usual rate equations of physical chemistry. The rate of soil removal in the Launder-Ometer could be reasonably well described by the equation of a first-order chemical reaction, ie, the rate was proportional to the amount of removable soil remaining on the fabric (51,52). In a study of soil removal rates from artificially soiled fabrics in the Terg-O-Tometer, the percent soil removal increased linearly with the log of cumulative wash time. 

In turbulent flow, axial mixing is usually described in terms of turbulent diffusion or dispersion coefficients, from which cumulative residence time distribution functions can be computed. Davies (Turbulence Phenomena, Academic, New York, 1972, p. 93), gives Di = l.OlvRe for the longitudinal dispersion coefficient. Levenspiel (Chemical Reaction Engineering, 2d ed., Wiley, New York, 1972, pp. 253-278) discusses the relations among various residence time distribution functions, and the relation between dispersion coefficient and residence time distribution. 

Another way to evaluate risks is to calculate the sensitivity of the total risk estimates to changes in assumptions, frequencies, or consequences. Risk analysts tend to be conservative in their assumptions and calculations, and the cumulative effect of this conservatism may be a substantial overestimation of risk. For example, always assuming that short-term exposure to chemical concentrations above some threshold limit value will cause serious injury may severely skew the calculated risks of health effects. If you do not understand the sensitivity of the risk results to this conservative assumption, you may misallocate your loss prevention resources or misinform your company or the public about the actual risk. 

Mercury is used in the manufacture of thermometers, barometers and switchgear, and in the production of amalgams with copper, tin, silver and gold, and of solders. A major use in the chemical industry is in the production of a host of mercury compounds and in mercury cells for the generation of chlorine. Mercury has a significant vapour pressure at ambient temperature and is a cumulative poison. 

Acute daphnia toxicity Biodegradability Physico-chemical properties cumulative... 

BASE SET Mutagenicity Toxicity to reproduction Toxicity to algae Acute daphnia and fish toxicity Abiotic and readily biotic degradability Additional physico-chemical properties 1 t/annum or 5 t cumulative... 

Note that total annual releases of less than 0.5 pounds from the processing or otherwise use of an article maintains the article status of that item. Thus, if the only releases you have are from processing an article, and such releases are less than 0.5 pounds per year, you are not required to submit a report for that chemical. The 0.5 pound release determination does not apply to just a single article, ft applies to the cumulative releases from the processing or use of that same typ>e of article (e.g., sheet metal or plastic film) that occurs over the course of the calendar year. 

There are concerns that land application of sludge will result in an increase of pathogenic bacteria, viruses, parasites, chemicals and metals in drinking water reservoirs, aquifers, and the food chain. This raises additional concerns of cumulative effects of metals in cropped soils. Research shows that if metals such as zinc, copper, lead, nickel, mercury, and cadmium are allowed to build up in soils due to many applications of sludges over the years, they could be released at... 

If workers are exposed simultaneously or successively to more than one chemical agent, the risk shall be assessed on the basis of the risk presented by all such chemical agents in combination. Usually, additive effects are assumed for the mixture of chemical agents, so the cumulative exposure is calculated as follows ... 

The deshielding effects of electronegative substituents are cumulative, as the chemical shifts for various chlorinated derivatives of methane indicate. 

Figure 1 Is a flow sheet showing some significant aspects of the Iterative analysis. The first step In the program Is to Input data for about 50 physical, chemical and kinetic properties of the reactants. Each loop of this analysis Is conducted at a specified solution temperature T K. Some of the variables computed In each loop are the monomer conversion, polymer concentration, monomer and polymer volume fractions, effective polymer molecular weight, cumulative number average molecular weight, cumulative weight average molecular weight, solution viscosity, polymerization rate, ratio of polymerization rates between the current and previous steps, the total pressure and the partial pressures of the monomer, the solvent, and the nitrogen.

The toxicological or cumulative effect of illicit drugs on the ecosystems has not been studied yet. Moreover, their fate and transport in the environment is to a big extent still unknown. Due to their physical-chemical properties (octanol-water partition coefficient, solubility, etc.) some of them, such as cannabinoids, are likely to bioaccumulate in organisms or concentrate in sediments whereas the rest, much more polar compounds, will tend to stay in aqueous environmental matrices. However, continuous exposure of aquatic organisms to low aquatic concentrations of these substances, some of them still biologically active (e.g., cocaine (CO), morphine (MOR) and MDMA) may cause undesirable effects on the biota. 

The structure and mathematical expressions used in PBPK models significantly simplify the true complexities of biological systems. If the uptake and disposition of the chemical substance(s) is adequately described, however, this simplification is desirable because data are often unavailable for many biological processes. A simplified scheme reduces the magnitude of cumulative uncertainty. The adequacy of the model is, therefore, of great importance, and model validation is essential to the use of PBPK models in risk assessment. 

REDUCED Additional acute toxicity Acute daphnia toxicity Biodegradability Physico-chemical properties 100 kg/annum or 500 kg cumulative... 

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