Optical method for determining impurities in periclase powders

A method for determining impurities in periclase powders by placing them in an immersion liquid with a refractive index equal to that of magnesium oxide is described. It is established that the composition of the semitransparent particles affects the color of the boundaries of the zone of transition from the immersion medium to the investigated substance. A method for determining the kind of transparent inclusions in periclase by observation in highly polarized transmitted light against light and dark fields is developed. It is shown that the transparent inclusions in particles, which are virtually indistinguishable in daylight, start to glow in polarized light against the background of a dark field.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 8, pp. 12–14, August, 1996.     

Extrapolation method of determining relative viscosity of polycaproamide in sulfuric acid

Conclusions A linear dependence of the relative viscosity of polycaproamide on sulfuric acid concentration has been confirmed.Regression equations have been found which make it possible to reduce the obtained using 93.5–96.5% sulfuric acid by wt. and using a variable sample weight of polycaproamide to a standardized relative viscosity st.Metrological certification of the extrapolated st method has been performed; the attainable accuracy is 0.010–0.015 when the number of determinations is 2.Inclusion of this procedure in the branch standard will make it possible to sharply reduce labor cost for analytical control.Translated from Khimicheskie Volokna, No. 4, pp. 58–60, July–August, 1988.     

Instrument for determining gel-particle content of polycaproamide

Conclusions A semiautomatic unit for determining gel-particle content in a solution of polycaprolactam has been fabricated and operated, based on the use of an LG209 helium-neon laser; it has increased sensitivity.It has been shown that even extended solid-phase final polycondensation of polycaproamide does not lead to a considerable increase in its gel-particle content.Translated from Khimicheskie Volokna, No. 5, pp. 57–58, September–October, 1988.     

An approximate method of evaluating spinning conditions for polycaproamide yarns

Conclusions An approximate criterion has been developed for evaluating technological processes for preparing technical polycaproamide yarns; it is based on analysis of physicomechanical properties.It is advisable to use the proposed method in comparing processes which differ in yarn stretch ratio.Translated from Khimicheskie Volokna, No. 4, pp. 16–17, July–August, 1986.     

A procedure for determining the elastic-relaxation characteristics of polycaproamide yarns

Conclusions A procedure has been developed for determining elastic-relaxation characteristics from short-term relaxation measurements.These characteristics reflect deformation properties rather completely; they describe and permit one to predict the process of stress relaxation, as well as stretching diagrams in the deformation range, with an accuracy up to 5%.Translated from Khimicheskie Volokna, No. 3, pp. 41–43, May–June, 1985.     

An autoanalyzer method for determining hexachlorophene in soap

An AutoAnalyzer method has been developed for determining hexachlorophene in soap. The free phenol group is condensed with 4-amino-antipyrine, and after oxidizing with alkaline potassium ferricyanide, the resulting quinonetype dye is colorimetrically measured at 480 mμ. Internal standards are employed having known amounts of hexachlorophene. The method is applicable to the range that would be expected in a germicide soap, i.e. from 0–2%. The overall precision was found to be ±0.022% (95% confidence limits) at the 1.00% level of hexachlorophene in soap. The presence of other germicide types such as for example, carbanilides or salicylanilides, should not interfere with the determination. This routinized method should prove useful in operations where numerous repetitive measurements are made.     

An improved method for determining polymer melting temperatures

A method for determining polymer melting temperatures, T_m, based on a simple modification of thermo-optical analysis is described. The method makes use of a small, highly conducting substrate and a preselected T_m, procedure which results in rapid heating rates (～1500°C/min) without temperature overshoot or superheating. Accuracies to within ±0.15°C are readily obtained. Application of the method to isothermally crystallized polyoxymethylene (Delrin 100 and 500) shows that T_m, increases with both time and temperature of crystallization as well as with increasing molecular weight. The potential of the method for characterizing polymer thermal history and molecular weight is discussed.     

An automated method for determining tocopherol in deodorized soybean oil

A method has been developed, utilizing the Technicon AutoAnalyzer, to determine the tocopherol content of deodorized oil. The chemistry of the Emmerie-Engel method, based upon the reduction of ferric chloride, is utilized in the development of this automated method. The tocopherol content of soybean oil is measured relative to a standard sample of d-α-tocopherol. The tocopherol content as measured by this method will include any other reducing substances present in the sample to be analyzed. The standard deviation, as derived from a pooling of the variances of four deodorized soybean oil samples is ± 0.0023% at the 0.1% level.     

An exact method for determining local solid fractions in discrete element method simulations

A novel solid fraction algorithm is presented which accounts for the partial volume of a sphere straddling cuboidal bin boundaries. The algorithm accounts for spheres intersecting a single plane (face), two perpendicular planes (edge), or three perpendicular planes (corner). Comparisons are made against the more common algorithm in which the solid fraction is determined by assigning the sphere's total volume to the bin in which the sphere's center of volume (COV) is located. Bin size‐to‐sphere diameter ratios >30 must be used to give errors <5% when using the traditional method when applied to simple cubic (SC) and hexagonal packing assemblies. Bin size‐to‐sphere diameter ratios larger than five are required for random sphere packings. Although time averaged solid fraction measurements are similar using either the exact or COV solid fraction schemes, the scatter in the COV method is much larger than for the exact method. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

An automated method for determining free alkalinity or acidity in soap

An AutoAnalyzer method has been developed to determine free alkalinity or acidity in soap by use of a mixed cresol red-phenolphthalein indicator solution and by measurement of the color developed at 550 mµ. An internal standard or reference solution is used consisting of a soap solution which has been adjusted to represent neutrality. The method was applied for 0 to 0.10% free alkalinity, calculated as sodium hydroxide, and for 0 to 0.50% free acidity calculated as oleic acid. Attainable precision of the method (95% confidence limits) in the ranges explored was found to be ±0.0025% for free alkali and ±0.05% for free acidity.     

An infrared microspectroscopy method for determining deterrent penetration in nitrocellulose-based propellant grains

Infrared microscopy was used to determine di-n-butyl phthalate, dinitrotoluene, and methyl centralite diffusion profiles in cross sections of nitrocellulose-based propellant grains. Absorbance of marker functional groups was determined at 25–50 µm intervals from the edge to the center of the sections. Comparison of IR and light microscopical data indicated that the optically visible boundary does not define the entire depth of deterrent penetration into propellant grains.