Zinc densities

The caloric levels of these diets varied considerably, partially because of differences In experimental design. In general, zinc Intake Increased as caloric Intake Increased, resulting In a more narrow range for the zinc densities of the diets—4.1 to 8.8 mg per 1,000 calories—than for the total zinc levels. In all of the studies, the research methods Involved chemical analysis of dietary composites. Few estimates of zinc Intake have been calculated from tables of zinc concentrations In food, even though this approach Is less complex and less costly. Calculation of zinc Intake from dietary survey data has been hindered by the limited proportion of the many foods available In the market place that have been analyzed for zinc. 

This low Intake results from the relatively low total energy consumption of the sedentary U.S. population and the relatively low density of zinc In the mixed U.S. diet. To achieve the RDA for zinc with a 3000 kcal dally Intake, dietary zinc density would have to be 5-7.5 mg/1000 kcal. The average mixed diet has a zinc density In the 3-4 mg/1000 kcal range (4). 

Zinc orthotitanate [12036-69-0] a white soHd having a density of 512(0) and a spinel stmcture, is obtained by heating the calculated... 

Table 1. Specific Energies and Energy Densities of Carbon-Zinc Cells ...

Some efforts toward sealed battery development (76) were made. However, a third electrode, an oxygen recombination electrode was required to reduce the cost of the system. High rate appHcations such as torpedo propulsion were investigated (77) and moderate success achieved using experimental nickel—zinc ceUs yielding energy densities of 35 W-h/kg at discharge rates of 8 C. A commercial nickel—zinc battery is considered to be the most likely... 

Zinc—Oxygen Cells. On the basis of reactants the zinc—oxygen or air system is the highest energy density system of all the alkaline rechargeable systems with the exception of the 2 Th reactants are cheap and abundant and therefore a number of attempts have been made to develop a practical rechargeable system. The reactions of this system are as follows ... 

The formulation of calcium chelate materials is based upon the formation of a low-solubiUty chelate between calcium hydroxide and a sahcylate. Dycal utilizes the reaction product of a polyhydric compound and sahcyhc acid. Other sahcyhc acid esters can be similarly used. Vehicles used to carry the calcium hydroxide, extenders, and fillers may include mineral oil, A/-ethyl- -toluenesulfonamide [80-39-7] and polymeric fluids. The filler additions may include titanium dioxide [13463-67-7] zinc oxide, sihca [7631-86-9], calcium sulfate, and barium sulfate [7727-43-7]. Zinc oxide and barium sulfate are useflil as x-ray opacifying agents to ensure a density greater than that of normal tooth stmcture. Resins, rosin, limed rosins, and modified rosins may serve as modifiers of the physical characteristics in both the unset and set states. 

The experiment testing was realized on the steel samples having zinc coating. The samples were made of steel tape used for cables protection having surface density 100 and 200 g/nf, which corresponds to the thickness of zinc costing about 14 and 28 micrometers. The measurements on the base of the presented above procedure has given the thicknesses of 20 and 25 micrometers. 

Simultaneous detenuination of Cu and Zn in the form of coloured PAR complexes is performed at pH 10 in the presence of pyrophosphate which binds the admixtures of Al, Fe and Mn into the inactive complexes. The measurements of the change in the optical density are made at 520 and 550 nm before and after the destmction of the complexes by EDTA, or at 530 nm before and after the destruction of the copper complexes by the thioglycolic acid and the destmction of the zinc complexes by EDTA. The detection limit for Cu is 2-5, for Zn - 3 p.g/diW. The application of these methodics at pH 8 enables one to determine simultaneously Cu and Zn at high excess of the latter. 

Concentration limits of the diphosphate-ion, admissible to determination of magnesium and cobalt, manganese and cobalt, zinc and cobalt by spectrophotometric method with application of the l-(2-pyridylazo)-resorcinol (PAR) are presented. Exceeding maintenance of the diphosphate-ion higher admissible supposes a preliminary its separation on the anionite in the H+-form. The optimum conditions of cobalt determination and amount of the PAR, necessary for its full fastening are established on foundation of dependence of optical density of the cobalt complex with PAR from concentration Co + and pH (buffer solutions citrate-ammoniac and acetate-ammoniac). 

Under aggressive corrosion conditions it is estimated that the maximum corrosion current density in a galvanised steel sheet will be 6 X 10 A m . Estimate the thickness of the galvanised layer needed to give a rust-free life of at least 5 years. The density of zinc is 7.13 Mg m , and its atomic weight is 65.4. Assume that the zinc corrodes to give Zn " ions. 

Figure 6-7 shows the effect of water conductivity on the rest potential of type AZ63, and M2 as well as of zinc and aluminum [23]. In cold waters with chlorides or sulfates, the polarization of magnesium anodes is low — even in the case of high current densities. This is demonstrated for 70°C with current-density vs. 

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