Determining pressing rates for refractory semidry bodies

Conclusions An inverse relationship was established for the permitted pressing rate and the ratio between the volume of the products and its double perimeter in plan. With an increase in the dimensions of the article it is necessary to reduce the pressing rate to exclude the formation of pressing cracks.Empirical equations are proposed which as a first approximation can be used for calculating the average rates and durations of pressing, and also for accumulating data connected with the question under discussion.Translated from Ogneupory, No. 5, pp. 17–21, May, 1971.     

Determining the accuracy of batching during pneumatic blowing of refractory semidry bodies

Summary During the filling of molds with semidry refractory bodies from one batch with compressed air, we get quite accurate filling.The filling accuracy improves with increase in the ratio of height of the mold to its area in plane.The distribution of the results of filling corresponds to the normal law.When molds are filled with pneumatic blowing, the coefficient of densification is much higher than for other methods of filling.     

损坏回转窑冷端耐火砖的主要原因及其对策

回转窑耐火砖衬的质量好坏，直接影响系统的正常生产、产品质量和生产成本。详细分析了回转窑冷端耐火砖的损坏原因．主要是压应力作用、挡砖圈设置不合理、耐火砖砌筑不规范和工艺操作制度不严等。在此基础上，进行了回转窑冷端耐火砖损坏的实例分析：同时对如何降低该区段耐火砖的损坏提出了相应的技术对策。     

Determining the moisture content of refractory concretes

Conclusions A portable apparatus was developed for measuring the moisture content of concrete at temperatures up to 200°C. The accuracy of the measurements is ±0.3 abs. %.The apparatus was tested on the main types of refractory concrete. Results were satisfactory.     

Determining the plasticity of clays and ceramic bodies

Glass and Ceramics -     

Effect of powder properties on discharge characteristics of cohesive carbonaceous fuel powders from a top discharge blow tank at high pressure

Abstract

Discharge experiments of two cohesive carbonaceous fuel powders (anthracite coal and petroleum coke) were carried out in a top discharge blow tank experimental system with design pressure up to 6.4?MPa. The effects of powder properties (particle size and powder category) on the discharge characteristics (including solid discharge rate, solids loading ratio, and discharge stability) from the top discharge blow tank at high pressure were investigated. Meanwhile, shear tests with a ShearTrac II shear tester were performed to investigate the flowability of these two cohesive powders. The results indicate that there exists a near-linear relationship between major consolidation stress and flow function (FF). As particle size decreases, the values of FF decrease and powder flowability becomes worse. However, as particle size decreases, the particle suspension velocity decreases correspondingly, and the gas permeability becomes worse and gas maintain ability becomes better, which contribute to higher solid discharge rate and better discharge stability, whereas solids loading ratio may have opposite variation tendency. Compared to petroleum coke with similar particle size, anthracite coal has better flowability and can obtain higher solid discharge rate and solids loading ratio, as well as better discharge stability. During the discharge processes of petroleum coke, it was found that as the number of discharge experiment increases, the discharge stability decreases correspondingly. After petroleum coke being discharged continuously for 4–6 times, the discharge process could not start again, adhesion phenomena of petroleum coke to the wall of conveying pipelines could be observed.     

SHS metallurgy of refractory inorganic compounds of chrome at atmospheric pressure

Laws of synthesis of cast refractory inorganic compounds and alloys in the regime of combustion at atmospheric pressure are studied. It is demonstrated that the combustion parameters and the composition of the synthesis products can be controlled by varying the ratio of the high-exothermic and low-exothermic components of the initial mixture. In domains of optimal parameters, it is possible to perform gravitational separation of the metal and oxide phases of combustion products and to obtain cast materials.     

Axial‐feed thermoforming of oriented polypropylene tubes

The effect of newly developed axial feed thermoforming process (AFTF) on mechanical properties and morphology were investigated to gain a better understanding of structure–properties–process relationship. The starting material for AFTF is an oriented polypropylene tube (OPP) produced in uniaxial direction by using solid state extrusion process. Morphological changes from solid‐state extrusion are briefly reported. A die‐less bulge testing system was designed to bulge OPP tube at a high temperature in biaxial direction. Wide‐angle X‐ray diffraction, field emission scanning electron microscope, and optical microscopy were used to characterize the microstructure of the extruded and bulged samples of OPP. In addition, tensile tests were carried out at room temperature of samples machined from the extruded and bulged tubes along the axial and hoop directions. The results show that tensile strength increases with draw ratio in extruded samples as well as improvements in ductility were obtained in die‐less bulge tests with an increase in axial feed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

The effect of interstitial air pressure gradients on the discharge from bins

This paper presents theoretical and experimental work on the effect of interstitial air pressure on the flow of granular materials from hoppers. In the first part of the paper, a theory is developed for the case of low Reynolds number flow in a conical hopper. In subsequent sections, the theory is extended to cylindrical bunkers, to higher Reynolds numbers, (where inertia effects cannot be neglected) and to cases where the compressibility of the gas is important. In all cases, the theory agrees well with experiment.     

Low-temperature synthesis of carbon nanotubes using corona discharge plasma at atmospheric pressure

A new method, which combines non-equilibrium plasma reaction with template-controlled growth technology, has been developed for synthesizing aligned carbon nanotubes at atmospheric pressure and low temperature. Multiwall carbon nanotubes with diameters of approximately 40 nm were restrictedly synthesized in the channels of anodic aluminum oxide template from a methane/hydrogen mixture gas by a.c. corona discharge plasma reaction at a temperature below 200 °C. It was observed that amorphous carbon deposited on the tops of the carbon nanotubes. The formation mechanism of carbon nanotubes synthesized by corona discharge plasma method was discussed.