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Silicon - The products of solid-phase mechanochemical interaction between pyrocatechol and silicon dioxide yielding a powdered composite were studied using a number of physicochemical methods. This... 相似文献
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Oleg A. Mezentsev Rixin Zhu Richard E. DeVor Shiv G. Kapoor William A. Kline 《International Journal of Machine Tools and Manufacture》2002,42(4)
A model-based method for fault detection in tapping based on torque and radial forces is proposed. The method allows the identification of faults typical of a tapping operation including axial misalignment, tap runout, tooth breakage both singly and together. The validation experiments have been run on aluminum 356 workpieces for different combinations of process faults. Results have shown that the model predictions are in good agreement with the experimental radial force and torque signals under various fault conditions. 相似文献
5.
The main phase transformations during synthesis of β‐sialon from kaolin of the Prosyanovskii deposit (Ukraine) under test-industrial production conditions have been studied. Sialon was prepared by carbothermal reduction in graphite-tube furnaces in nitrogen. It is shown that the process is characterized by the simultaneous occurrence of several chemical reactions with formation of intermediate phases (Si2ON2, X1‐phase), silicon carbide, and (apart from β‐sialon) sialons based on AlN polytypes. The phase composition of the final product is determined not only by the charge composition but also by the set of production parameters. Results of the work may provide a basis for commercial preparation of sialon powder. 相似文献
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A physically simple but mathematically cumbersome problem of rotating heavy string with one fixed top point was studied. A nonlinear equation of its two-dimensional shapes of relative equilibrium was obtained and solved numerically. A linear case of small displacements was analyzed in terms of Bessel functions. The qualitative and quantitative behavior of the problem is discussed with the help of a bifurcation diagram. Dynamics of the two-dimensional model near the equilibrium positions were studied with the help of a simulation using the absolute nodal coordinate formulation (ANCF); the equilibriums were found to be instable. The reason for instability is explained using a variational principle. The outlines for further full three-dimensional analysis are briefly proposed in this paper, and the full derivation will be explained in the next paper. 相似文献
8.
Gabriella Tranell Oleg Ostrovski Sharif Jahanshahi 《Metallurgical and Materials Transactions B》2002,33(1):61-67
The redox behavior of titanium in CaO-SiO2-TiO
x
melts was investigated using a slag-gas equilibrium technique. Titanium partitioning between Ti3+ and Ti4+ valency states and the ratio of activity coefficients of TiO1.5 and TiO2 were determined as functions of oxygen partial pressure, temperature, and slag composition. The equilibrium experiments were
carried out at temperatures between 1783 and 1903 K under CO-CO2-Ar gas atmosphere with oxygen partial pressure ranging from 10−12 to 10−7 atm (1.01×10−10 kPa to 1.01×10−5 kPa). The slags had CaO/SiO2 ratios between 0.55 and 1.35 and total titanium oxide concentrations from 7 to 50 mass pct. Experimental results showed that
the Ti3+/Ti4+ ratio in CaO-SiO2-TiO
x
slags, containing up to 50 mass pct TiO
x
, increased with decreasing oxygen partial pressure and decreased with increasing CaO/SiO2 ratio and decreasing temperature. Measured variation of the redox ratio Ti3+/Ti4+ with oxygen partial pressure closely followed the ideal behavior. Increasing the CaO/SiO2 ratio increased the ratio of activity coefficients of TiO1.5 and TiO2. The effect of total titania content on this ratio was more complex and in accord with Raman spectroscopy data. 相似文献
9.
A population balance method in which continuum and discrete phases are integrated is developed to simulate the evolution of polydisperse population of bubbles in a turbulent pipeline flow. The investigation is focused on the effect of the coalescence efficiency on this evolution. A dilute system of bubbles under microgravity conditions is considered. It is found that if the initial coalescence efficiency is low, a slight increase produces a significant effect on the bubble coalescence rate, and thus on the evolution of the population. If, however, the initial coalescence efficiency is high, its increase results in a marginal effect on the way the population evolves. The results of simulations are validated against experimental data on the population mean. 相似文献
10.
Efficient scheduling systems are able to enhance production flow and production times in process industry. Scheduling, in this case, means simulation with alternatives of resources and/or activities. The result will be the exact time of output for each activity and the resulting profiles of capacity vectors concerning the recommended resources. In contrast to this, common planning systems add only the user defined production time of activities. Especially for flexible plants with batch production and a variable spectrum of products, as weil as for plants in the stage of design or enlargement, scheduling systems can be very helpful in identifying bottlenecks and over-capacities. Therefore, reduction of costs in a significant extent and additional benefits can be realized, provided that the individual conditions and objectives have been taken into account. 相似文献