Uniqueness of compressible micropolar fluid flows

The paper examines the uniqueness of compressible micropolar fluid flows over an arbitrary region $\text{R(t)}$ with a smooth boundary $\text{?R(t)}$. It is shown that there is at most one solution of the flow equations and boundary conditions which corresponds to suitably assigned initial values of the density, velocity, microrotation and temperature fields. The analysis rests on the use of differential inequalities involving the time derivatives of certain energy integrals.     

Direct Pyrolysis of Raw Rice Husks for Maximization of Silicon Carbide Whisker Formation

A new alternate route for the production of SiC from rice husks has been described. The proposed single-stage process has the advantage of reduced time of production and a much higher yield of SiC whiskers than the conventional two-stage process. Direct pyrolysis of raw rice husks was carried out in a graphite furnace under vacuum and the reaction products were analyzed through macroscopic examination, XRD, SEM, and chemical analysis. Effects of time and temperature on the relative yields of the various reaction products have been determined over a wide range. The pyrolysis of raw rice husks has been found to be accompanied by four different competitive processes, viz., formation of SiC whiskers, formation of SiC polycrystals, crystallization of amorphous silica, and graphitization of amorphous carbon. Crystallization of silica and formation of SiC( w ) are dominant processes at 1150° to 1310°C. At higher temperatures formation of SiC polycrystals and graphitization of carbon are more favored. A multistep pyrolysis to 1310°C was found to yield a still higher amount of SiC( w ) than direct pyrolysis.     

Optimization of wing structures to satisfy strength and frequency requirements

In this investigation minimum weight design of wing structures with restrictions on strength, stability and frequency characteristics is attempted. The multiweb delta wing structure is idealized with three different kinds of finite elements. The constant stress triangular plate elements, the rectangular shear panels and pin jointed bar elements are used to represent, respectively, the cover skins, webs and the stringers of wing structures. A parametric study is made to reduce the number of design variables which in turn reduces the required computational effort. The feasibility of employing linearly approximated redesigns is investigated. Numerical results are presented to illustrate the feasibility. Off-design charts have been obtained by performing sensitivity analysis about the final optimum design point.     

The evening news and presidential evaluations.

Examined the effects of TV news accessibility, relevance, and expertise on presidential evaluations in 2 experiments. In each, Ss viewed TV news programs in which the amount of attention given to various national problems was manipulated. In Exp I, 73 undergraduates were divided among 3 conditions defined by level of exposure to stories about energy. Ss viewed 40 mins of news taken from 1979–1980 newscasts before answering questions about President Carter's performance, competence, and integrity. In Exp II, 140 Ss from the community watched newscasts that varied with regard to exposure level to particular national problems. After rating Carter's performance, Ss also completed a political expertise questionnaire. Results show that by drawing attention to certain national problems while ignoring others, TV news programs can define the standards by which presidents are evaluated. As predicted, this effect was greater for evaluations of general performance than for judgments of his competence and integrity, and it was more pronounced among novices than among experts. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing the consistency of the Maxwell-Stefan formulation when predicting self-diffusion in zeolites with strong adsorption sites

The Maxwell-Stefan (MS) formulation, as applied to zeolites that contain both weak and strong adsorption sites, such as ZSM-5, is compared to dynamic Monte Carlo simulations, for the limiting case of single-component self-diffusion. This study is intended as a consistency check, and as a step towards an analytical or semi-analytical theory for self-diffusion in zeolites with multiple types of sites. In its original form, when it is assumed that ζ, the ratio of the self-exchange coefficient to the corrected diffusivity, is equal to 1, the MS formulation performs well for silicalite, the all-Si version of ZSM-5. However, when there are lattice heterogeneities or the topology of the pore network differs from that of silicalite, it is necessary to assume [Formula: see text]. Because ζ is generally occupancy dependent, the theory is unsuited as a fully predictive theory for self-diffusion in heterogeneous microporous solids, unless a theory for ζ is derived. However, since several studies have demonstrated that the MS formulation is able to predict multi-component diffusivities from single-component diffusivities for zeolites with one type of site, an extension to zeolites with multiple types of sites would be very valuable.     

Expanding the optical trapping range of gold nanoparticles

We demonstrate stable three-dimensional (3D) single-beam optical trapping of gold nanoparticles with diameters between 18 and 254 nm. Three-dimensional power spectral analysis reveals that, for nanoparticles with diameters less than 100 nm, the trap stiffness is proportional to the volume of the particle. For larger particles, the trap stiffness still increases with size, however, less steeply. Finally, we provide numbers for the largest forces exertable on gold nanoparticles.     

A system approach to information system: Design for a city planning agency

Information system design forms the most vital element in designing an organization. An information system for a city planning agency is a combination of people, computer hardware and software, a dynamic data base and a set of generalized interactive algorithms.City planning agencies require complete and current information in order to provide input into municipal government decision process. This paper presents a model for an information system based on the operational functions of various city departments. The emphasis of this paper is on system engineering considerations and there is no attempt to provide a detailed programming solution. Basic considerations include: operational requirements, planning requirements, political environment and level of computer expertise. The basic components of the model are an on-line interactive system with a data-base shared by the participating departments.