Practicable building frame analysis

The analysis of building frames is carried out using a two-stage finite element process, which considers a full three-dimensional model of the structure, including lateral and vertical loadings. Although the analysis process requires somewhat more data preparation than current design office methods, it does involve techniques which are considerably less expensive than full finite element analysis both in terms of CPU costs and data preparation, and it is amenable to fairly routine procedures which could be made automatic. The advantage is a rational analysis, which can take care of sidesway analysis in a realistic way, and can handle such complexities as holes for stairways, and offset columns. Dynamic analysis and stability analysis are also practicable extensions, since the displacement equations which must be solved are formulated for the model with reduced degrees of freedom, in a manner similar to the familiar substructure approach in matrix analysis. The authors also report an extension to the analysis in progress. The results of an analysis of a 10-storey building frame are presented and compared to earlier studies.     

The relation between scabies and hypersensitivity to antigens of house dust mites and storage mites

Twenty five non-atopic scabietic patients were examined to estimate their reaction to crude house dust mite Dermatophagoides farinae (D. farinae) and storage mite Tyrophagus putrescentia (T. putrescentiae) antigens. Skin prick testing (SPT) by extracts of both mites antigens showed significant higher positive results in scabietics when compared to non-scabietic control subjects. Moreover, 60% and 56% of scabietic patients showed positive levels of specific anti-D. farinae and T. putrescentia IgE respectively in comparison to 13.4% & 20% of control subjects. A significant difference has been obtained when the total number of positive results were compared to the total number of negative ones. The results revealed that there is an evidence of cross reactivity between Sarcoptes scabiei antigens and extracts of D. farinae and T. putrescentiae, and the hypersensitivity to house dust mite and storage mite antigens was significantly higher in scabietics than in controls. It could be concluded that there is some proof that other mites rather than Sarcoptes scabiei may have a role in the pathogenesis of scabies and the cross reactivity between S. scabiei and house dust mite and storage mite may explain the persistence of symptoms in some cases even after proper treatment of the disease.     

Comments on "Parameter estimation in multivariative stochastic difference equations"

In the above paper Kashyap and Nasburg introduced canonical forms II and III to represent multivariate systems. The limited informarion estimate to obtain the parameters of the system was presented, in which the system is decomposed by using either of the proposed canonical forms into subsystems. As a result the estimation problem was considerably simplified. In this correspondence, it is observed that the canonical form I which has the smallest number of parameters can be decomposed into subsystems just as well, and that the class of models in canonical form I, which is the usual representation, is wider than canonical forms II or III. The question therefore is: what is the real merit of implementing those new canonical forms II and III?     

Effects of lupin oil on carp lipids during chilling 1. Changes in lipid class composition

The effect of lupin (Lupinus termis) oil on the muscle lipids of carp (Cyprinus carpio) during chilling was studied. During chilling, total lipids decreased whereas triglycerides remained almost constant. Neither the behavior of total lipids nor that of triglycerides during chilling was affected by the composition of the dietary lipids. The proportions of ?free”? fatty acids increased and the proportions of phospholipids decreased during chilling. These changes were markedly affected by the composition of the diet.     

The impact of grain size on the photogenerated current in polycrystalline silicon solar cells

A simple one-dimensional model is proposed in order to investigate the impact of grain boundary recombination on the photogenerated current of polycrystalline silicon solar cells. The model is applied to calculate the degradation of the photocurrent caused by grain boundary recombination and the effective internal quantum efficiency as a function of grain size. It is found that the impact of grain boundary recombination on the photocurrent is significant in cells dominated by the long wavelength response, and in thicker cells.     

Scaling and Roundoff in Fixed-Point Implementation of Control Algorithms

The analysis and design of digital controllers on microprocessors using fixed-point arithmetic have been considered. Three scaling techniques are applied to the design of digital controllers in such a way as to avoid overflow and to optimize the signal-to-roundoff noise ratio. Both the scaler and the multivariable cases are treated. Statistical estimates of the steady-state roundoff and quantization errors are derived.     

Characterization of some poly(methyl methacrylate) prepared by emulsion polymerization in presence of egyptian delta titano magnetite ore (EDTMO)

The emulsion polymerization of methyl methacrylate was studied in water using potassium persulphate as initiator and dedocyl–benzene sodium sulphonate as emulsifying agent at 85°C. The effect of Egyptian delta titano magnetite ore (EDTMO) upon the activation energy and on the mean average molecular weights of the obtained polymers was studied. It was found that the viscosity average molecular weights increase with decrease of reaction temperature and initiator concentration but increase with increase of monomer concentration in the reaction medium. Some of the polymer samples prepared in absence and in presence of some (EDTMO) were separated on tlc plates according to molecular weight in binary mixture, benzene:methanol (1:1.4 by volume) at 30°C. The tlc techniques were performed to give an idea about the molecular weight distribution of the polymer samples obtained.     

Influences of Mn doping on the microstructural,semiconducting, and optoelectronic properties of HgO nanostructure films

Mn-doped HgO nanostructured thin films (Hg_1-xMn_xO) have been prepared using electron beam evaporation technique on Corning glass (1022) substrate at room temperature with different concentrations x = 0, 0.015, 0.05, 0.1, 0.15, and 0.2. The microstructural, morphological, semiconducting, and optoelectronic properties of the films have been investigated. The X-ray diffraction spectra suggest a hexagonal wurtzite type structure with lattice parameters decreased with increasing Mn content. It was found that the average particle size of the films decreases with increasing Mn doping which is confirmed by FE-SEM and AFM micrographs. The optical band gap of the investigated Mn-doped HgO nanocrystalline films is determined from the absorption coefficient and found to increase with the increase of Mn concentration which is attributed to the sp-d exchange interaction and/or the quantum confinement effect. The refractive index and extinction coefficient of the Mn-doped HgO films are also reported. The refractive index dispersion n(λ) is analyzed by single-effective-oscillator dispersion model proposed by the Wemple–DiDomenico (WDD). The oscillator parameters were estimated. The obtained dispersion values are suitable for the design of optoelectronic devices.     

Morphological characterization of wheat powders, how to characterize the shape of particles?

A quantitative method was developed to evaluate the shape of wheat powder particles. The method relies on a dispersion system designed to scatter particles on a transparent glass slide. A digital image acquisition system based on specialized software was then used to analyze the acquired images. Particles (1000) were analyzed with respect to four shape factors (circularity, elongation, convexity, and compactness). Dispersion of experimental values characterizes the large heterogeneity in wheat flour particles’ shapes. The results demonstrate that small particles of wheat powders have more regular shape than big ones, due to possible erosion mechanisms occurred during milling.