Separation-bubble flow solution using Euler/Navier-Stokes zonal approach with downstream compatibility conditions

An Euler/Navier-Stokes zonal scheme is developed to numerically simulate the two-dimensional flow over a blunt leading-edge plate. The computational domain has been divided into inner and outer regions where the Navier-Stokes and Euler equations are used, respectively. On the downstream boundary, compatibility conditions derived from the boundary-layer equations are used. The grid is generated by using conformal mapping and the problem is solved by using a compressible Navier-Stokes code, which has been modified to treat Euler and Navier-Stokes regions. The accuracy of the solution is determined by the reattachment location. Bench-mark solutions have been obtained using the Navier-Stokes equations throughout the optimum computational domain and size. The problem is recalculated with sucessive decrease of the computational domain from the downstream side where the compatibility conditions are used, and with successive decrease of the Navier-Stokes computational region. The results of the zonal scheme are in excellent agreement with those of the benchmark solutions and the experimental data. The CPU time saving is about 15%.     

Thermophilic anaerobic digestion of palm oil mill effluent

A laboratory study was carried out using the thermophilic anaerobic process to treat palm oil mill effluent containing 67,000 mg 1⁻¹, COD, 31,800 mg 1⁻¹ suspended solids and a pH of 4.5. Completely mixed reactors were operated to evaluate the effects of feed strength and solids retention times on the system's performance. A range of 5–35 days solids retention time was studied. COD reduction was 72% for the 5-day unit and greater than 90% for units having detention time 15 days or more. pH of all units was self adjusted to 7.4. Gas production was, in general, greater than 0.3 m³ kg⁻¹ volatile solids feed.     

TORUS: A step towards bridging the gap between data bases and the casual user

This paper describes TORUS, a natural language understanding system that serves as a front end to a data base management system in order to facilitate communication with casual users. The system employs a semantic network to store knowledge about a data base of student files. This knowledge is used to find the meaning of each input statement, to decide what action to take with respect to the data base, and to select information that must be output in response to the input statement. A prototype version of TORUS has been implemented.     

三坐标测量机测头半径对测量数据的影响及其消除方法

分析了三坐标测量机测头半径对测量数据的影响,对由三坐标测量机在复杂曲面上测得的点,每一截面的测量点用大挠度三次样条连接,而各截面间采用基样条函数连接,组成基样条函数和大挠度三次样条曲线的混合曲面,在此基础上推导出测量点所形成的曲面及其法向等距面的数学模型,从而消除测头半径的影响。     

X-ray photoelectron spectroscopy and corrosion studies of zinc phosphate coated on 7075-T6 aluminium alloy

Coated layers which formed on 7075-T6 aluminium alloy surfaces after treatment in zinc phosphate (ZPO) suspensions adjusted to different pH values (3.5, 5.0, 6.6, 10.5 and 13.0) were characterized by X-ray photoelectron spectroscopy (XPS). Comparative XPS tests were also made after the treated surfaces were exposed to a 3.5% NaCl solution for 5 h. The processes of coating from solution, oxidation, etching and bulk diffusion were all involved, although in different proportions, in the different treatments. The amounts of zinc and phosphorus in the uppermost layers were enhanced when the coating was at pH values of 5.0, 10.5 and 13.0, and in each case a mixed ZnO _x -AlO _x -ZPO structure was apparently formed. The coating prepared at pH=13.0 appeared to provide the best corrosion protection.     

Processing causally relevant information.

Two experiments tested an information-processing model of causal judgment proposed by D. L. Hamilton, P. D. Grubb, D. A. Acorn, T. K. Trolier, and S. Carpenter (1990). In Exp 1 the explanatory quality (plausibility, sufficiency, and likelihood) of context information pertaining to a behavioral event was varied independently of its implications for internal or external causality. In Exp 2 perceivers performed tasks requiring either item-specific elaboration or relational encoding of the information in addition to making external versus internal causal attributions. Results imply that (a) perceivers encode the causal potency of individual information items even when the judgment task requires only a general internal versus external attribution and (b) perceivers engage in multiple modes of encoding information, depending on the implicational structure of the information array and on the explanatory quality of the context items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of thermal stress in graphite intercalated with bromine

The thermal stress of graphite intercalated with bromine was found to increase from zero at about 100°C to about 1.3 MPa at 200°C. The effect was reversible with hysteresis. The thermal stress increase had a sharp temperature dependence due to its association with the exfoliation phase transition.Paper presented at the Ninth International Thermal Expansion Symposium, December 8–10, 1986, Pittsburgh, Pennsylvania, U.S.A.     

Experimental verification of the analysis of umbrella parabolic reflectors

Gored umbrella parabolic reflectors with symmetric aperture illumination have been treated analytically in a recent paper. This communication extends the analysis to the case where the primary feed illumination is not symmetric, because real primary feeds usually have unequalE- andH-plane beamwidths. The gore loss and the shift in the defocusing curve obtained using the modified gain expression are in excellent agreement with values measured for a smooth parabolic reflector and a gore parabolic reflector of the same diameter.