KINETICS OF PERCHLOROETHYLENE EXTRACTION DESULFURIZATION OF COALS

ABSTRACT

The perchloroethylene coal cleaning process selectively removes the organic sulfur from coal via a hybrid mechanism of chemical reaction and physical solvation It was found that the chemical reaction was catalyzed by the inorganic species present in the coal. In this paper, a kinetic study was experimentally carried out to determine rate constants of the reaction. It was confirmed that the extent of organosulfur extraction depended strongly on the type of coal, and also that there is a critical extraction time which is required as the minimum time for each type of coal. Isothermal batch kinetic studies were done for various types of coal. A relation was established between the type of coal and its kinetics and hence the minimumtime for extraction.     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY TRICHLOROETHANE EXTRACTION

Desulfurization of coal involves removal of both organic and inorganic forms of sulfur. In this paper, the process feasibility of organic desulfurization of coal using 1,1,1-trichloroethane (TCA) as the solvent, is established. Sulfur solubility curve in tnchloroethane was obtained. The process conditions of this novel process were critically assessed. From the solubility curve it was concluded that the process should be carried out at or near the normal boiling point of the solvent. Comparisons between the TCA extraction and the perchloroeihylene (PCE) process have been presented. Since the boiling point of tricbloroethane is quite low, the process conditions are very mild in comparision to the PCE process. It was found that the TCA process is capable of removing organosulfur from coal more selectively than the PCE process. The sulfur containing organic species in the extract obtained from     

Burg 算法在地震数据反褶积中的应用

Burg 算法的一个重要概念是在求自相关函数时,对数据时窗外仅作最大随机性假设,而不认为等于零。用这一概念,可以外推自相关函数。当用 Burg算法求反滤波器预测误差因子 a_i~((m))时,既不计算自相关函数,也不计算反滤波因子的全部系数值,而只需要计算因子最末一点的系数 a_m~((m)),并且这一计算仅限定在数据时窗范围内进行。本文将 Burg 算法具体应用于地震数据反褶积中,在求 a_m~((m))时作了部分的修改,提高了稳定程度,改善了反褶积的地震剖面质量。从已进行的实际地震数据试算结果来看,只要处理参数使用恰当,地震剖面上信号的分辨率均有十分明显的提高,并且信噪比也有所改善。     

Effect of different coagulants on the isoflavone levels and physical properties of prepared firm tofu

The objective of this study was to understand the effect of different coagulants in their ability to retain isoflavones in prepared firm tofu. Harovinton beans were processed to obtain soymilk and a specific amount of this soymilk was coagulated using different types of coagulants for the preparation of tofu. A reversed phase high performance liquid chromatographic method was used for determining the concentration of isoflavones in tofu and whey. Quality parameters such as the texture, color and moisture of tofu, prepared from different coagulants were also determined in this study. Tofus coagulated with different coagulants were found to contain different amounts of isoflavones. Calcium sulfate was found to be the most suitable coagulant for tofu making in terms of its high yield, retention of maximum amount of isoflavones and in obtaining a firm, but not hard texture of tofu.     

Evaluating of traumatic brain injuries using artificial neural networks

The purpose of this study is to develop a diagnostic system to detect the severity of traumatic brain injuries using artificial neural networks. Three layered back propagation neural network with an input layer of 10 nodes whose output providing the inputs to a hidden layer was used. Thirty-two patients with traumatic brain injuries in different age and gender were taken in the study. Electroencephalography, Trauma and Glasgow coma scores were used for evaluating the data. The results obtained from the system were compared with the findings of neurologists. We found a significant relationship between the findings of neurologists and systems output for normal, mild, moderate and severe electroencephalography tracing data. Getting this system in routine use will lead to make a rapid decision for the degree of trauma with electroencephalography and revised trauma score.     

3D reconstruction based on hard tissue microtome cross-section pictures in dentistry

The aim of this study was to examine the accuracy of the computerized 3D surface analyzing and volume measuring method in dentistry. Two different types of test objects were used in the first part of the measurements. Each sample of the two groups was cross-sectioned using a hard tissue microtome. The sections were photographed on both sides and were projected on a graphical tablet and analyzed using a computer program. The measured and calculated parameters were compared. In the second part, 200 microm thick horizontal sections were prepared from 11 human incisor roots using the hard tissue microtome. This way, five sections were prepared from the apical 2 mm of each root. The effects of section thickness and number were modeled by decreasing the inclusion rate of the obtained number of sections from 10 to 2 and its influence on the calculated results was determined. This method was suitable for the approximation and analysis of 3D parameters. The results indicated that using 200-300 microm section thickness, the measured values were approximately 8-21% lower than the real parameters.     

Endosonographic image of a retrorectal bowel duplication: report of a case

PURPOSE: Endosonographic image and surgical therapy of a retrorectal bowel duplication are described. METHODS, RESULTS, AND CONCLUSIONS: Compared with standard investigations, the most accurate information about a retrorectal mass in a 35-year-old woman could be obtained by means of endorectal ultrasound. Guided by endorectal ultrasound, the mass was excised using a transanal-transrectal approach, and Kraske's operation could be avoided. Additionally, histopathologic analysis of this rare disease is presented.     

Hexagonal dislocation networks in titanium

Hexagonal dislocation networks which occurred in as-annealed commercial Ti-A 50 rod and following partial extrusion under hydrostatic pressure at room temperature were studied using transmission electron microscopy. For the as-annealed condition networks were observed on the prism, basal and {2•1•1x} planes, while for the extrusion networks were only observed on the basal plane. The various stages in the development of the networks are presented and mechanisms by which they form are proposed. The self energies of the dislocation hexagons constituting the various networks are calculated using the equations proposed by de Wit and Ruff. They increase in the order: a) networks on the basal plane in the as-annealed condition, b) networks on the prism plane in the asannealed condition and c) networks on the basal plane in the partially extruded condition. This paper is based on Doctoral Thesis presented in October 1973 by S. P. AGRAWAL to the Department of Metallurgical Engineering and Materials Science at the University of Kentucky.