1,257 research outputs found
Ore dressing laboratory for the Missouri School of Mines and Metallurgy, Rolla, Missouri: design, description, drawings for erection, bills of material, and specifications
The work of preparing suitable drawings and specifications for the construction of the new Ore Dressing Laboratory of the Missouri School of Mines and Metallurgy was begun about August 15, 1909. At that time general plans, as shown in drawings No. 1 and No. 2, were drawn up and submitted for approvaleaf With certain minor alterations, to be mentioned under the section on specifications, these plans will be followed in the installation of machinery. Other detail drawings were made by the class in Ore Dressing Problems under the direction of the writer during the school term ending March 12, 1910. It is not intended that this work shall contain such complete plans, specifications, and detail working drawings as would be necessary if the installation were to be made by outside contractors. The work of installation and construction will be conducted during the summer of 1910 by mechanics in the employ of the school and under the supervision of the writer, or under the direction of some one else equally familiar with the conditions at hand. On this account the specifications and working drawings are not complete in all details, as a few verbal instructions at the time of installation, from one familiar with the work, are frequently more useful to the mechanic than a sheet of detail drawings and pages of specifications --Introduction, page 1
The thermal conductivity of refractories
The usefulness of correct data in regard to the thermal conductivity of refractories and other materials used in the construction of metallurgical and industrial furnaces is quite generally recognized. Numerous investigations of this property of refractories have been conducted, and in many cases the published data of different investigators are somewhat conflicting. This is particularly true of figures pertaining to materials intended for use at high temperatures, and it is with such materials that the metallurgist is mot interested. The difficulties in the way of precise determinations of thermal conductivities at elevated temperatures are numerous, and it is not particularly surprising that there exists a set of data for each method of determination, the figures of which fail to agree closely with those obtained by other methods. However, it should be remembered that the variations in the figures of different observers are doubtless due to variations in the materials tested as well as to differences between, or inaccuracies of, the methods employed. The present paper deals with the methods and results of an investigation designed to develop a practical and reasonably accurate means of determining the thermal conductivity of regular kinds of brick, under conditions approaching those of practice, and without the necessity of preparing special shapes or samples of the materials being tested. In reviewing the methods that have been used and proposed for determining the conductivity of refractory materials, they fall naturally into three general classes, calorimeter methods, measured heat-input methods, and comparison methods --Page 285
The effect of certain minerals upon the volatilization of silver chloride
The work undertaken in this investigation was first suggested in connection with the analytical determination of Silver and Chlorine by weighing silver chloride. Later, however, the experiments assumed a metallurgical character. The final purpose of the experiments was to determine the effect of a few of the common mineral constituents of ores on the loss of silver during a chloridizing roast. In the metallurgy of silver it is frequently necessary to change the silver bearing minerals into silver chloride --page 1
Deaths Exceed Births in Most of Europe, But Not in the United States
In this brief, authors Kenneth Johnson, Layton Fields, and Dudley Poston, Jr. present important new findings about the diminishing number of births compared to deaths in Europe and the United States from their recent article in Population and Development Review. Their research focuses on the prevalence and dynamics of natural decrease in subareas of Europe and the United States in the first decade of the twenty-first century using counties (United States) or county-equivalents (Europe). The authors report that 58 percent of the 1,391 counties of Europe had more deaths than births during that period compared to just 28 percent of the 3,137 U.S. counties. Natural decrease is more widespread in Europe because its population is older, fertility rates are lower, and there are fewer women of child-bearing age. Natural decrease is a major policy concern because it drains the demographic resilience from a region, diminishing its economic viability and competitiveness. The implications of the recent European immigrant surge for natural decrease are uncertain, but the authors’ analysis suggests that natural decrease is likely to remain widespread in Europe for the foreseeable future
The Statistical Modeling Of The Fertility Of Chinese Women
This article is concerned with the statistical modeling of children ever born (CEB) fertility data. It is shown that in a low fertility population, such as China, the use of linear regression approaches to model CEB is statistically inappropriate because the distribution of the CEB variable is often heavily skewed with a long right tail. For five sub-groups of Chinese women, their fertility is modeled using Poisson, negative binomial, and ordinary least squares (OLS) regression models. It is shown that in almost all instances there would have been major errors of statistical inference had the interpretations of the results been based only on the results of the linear regression models
Administrative Law -- Constitutional Law -- Delegation of Nonjudicial Duties to the North Carolina Superior Courts
Activation and Metabolism of P-Nitrosophenoland 2,2\u27-Thiobis-Ethanol by Horse Liver and Human Alcohol Dehydrogenase: Toxicological Implications.
C-nitroso compounds are reactive intermediates in the toxic sequelae of nitroarene metabolism. Alcohol dehydrogenase (ADH) contributes significantly to NADH-dependent C-nitroso reduction by cytosol relative to NAD(P)H: quinone oxidoreductase (NQOR). NADPH-dependent pNSP reduction by liver cytosol of ADH+ animals is mostly dicumarol-sensitive which implicates NQOR as the major NADPH-dependent activity. Although, extensive structural homology between horse and different isozymes of human ADH exist, significant differences occur within the active site, which account for great variability among substrate specificities, kinetic constants, and response to inhibitors. We have studied the metabolic activity of horse liver alcohol dehydrogenase (HLADH), purified class I alphaalpha, beta 1beta1 and beta2beta2, class II pi, class III chi and class IV sigma human isozymes, and human liver cytosol (HLC) towards the C-nitroso substrate pNSP. Significant differences in the reaction rates towards pNSP were observed between HLADH and the human isozymes. The relative order of the rates of pNSP reduction by ADH was HLADH \u3e alphaalpha \u3e pi \u3e sigma \u3e chi \u3e beta2beta2 \u3e beta1beta 1. pNSP reduction catalyzed by HLADH, purified class I alphaalpha, beta1beta1, and beta2beta 2, class III chi and class IV sigma human isozymes show pH dependence with maxima greater than or equal to pH 6. This pH dependence seemingly reflects a protein moiety involved in the proton relay system. Thiodiglycol (TDG) can undergo oxidation catalyzed by ADH. We have compared the catalytic activity of purified human liver class I alphaalpha, beta 1beta1, beta2beta2 and gamma 1gamma1 ADH, class II pi ADH, class III chi ADH, and class IV sigma ADH with respect to TDG oxidation. Specific activities with respect to TDG were 123, 79, 347, 647, and 12 nmol/min/mg for the alphaalpha, beta 1beta1, beta2beta2, gamma 1gamma1, and pi ADH, respectively. Class III chi ADH did not exhibit activity with this substrate. The specific activity of class IV sigma ADH was estimated at about 1632 nmol/min/mg. The activities of class IV sigma and class I gamma1 ADH are of significant interest because of their prevalence in the eyes, lungs, stomach and skin, all potential target organs of sulfur mustard toxicity
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