The Einstein relation for degenerate semiconductors with nonuniformband structures

Modification of the Einstein equation for semiconductors with nonparabolic energy bands and doped nonuniformly with impurity atoms is suggested. The suggestion is based on a new approximation of the Fermi-Dirac integral of order 1/2, namely, F_1/2(η_n), where η_n is the reduced Fermi level for electrons. The relation reduces to that for semiconductors with parabolic energy bands and doped uniformly with impurity atoms under appropriate boundary conditions. A comparison of the calculated and exact results for F_1/2(η) is found to be very encouraging     

Fractal model to predict the crack roughness effect on the local bending compliance of circular shafts

In this paper the local compliance due to a transverse fractal crack in a shaft under pure bending is investigated. In a fractal crack, the surface is considered irregular and it is characterized by the presence of nonuniformities at different scales. Therefore, the crack surface can be modeled as a fractal surface with fractal dimension D. An analytical model for the compliance coefficient is presented with and without the effect of the surface roughness. The results obtained shows that as the dimension of the fractal surface increases the compliance increases as well. It is shown that this behavior conforms well with existing experimental results.     

Grid computing: a STOPE view

Grid computing is emerging as the foundation upon which virtual organizations can be built. Such organizations are becoming of increasing importance for tackling various projects, both in academic and in business fields. This paper is concerned with presenting an integrated view of the grid to readers interested in understanding it, or perhaps in developing it further or making use of it in the future. The target view is based on the STOPE (strategy/technology/organization/people/environment) framework that has previously been used to integrate the issues of various information technology problems over its well‐defined domains. For strategy, the view considers the reasons associated with the need for the grid, including grid services and grid benefits. For technology, the technical components of the grid and their functions are taken into account. For organization, the organizations concerned with the development, technology production, service provisioning and use of the grid are considered. For people, those associated with the grid in the related organizations are taken into account. For the environment, rules, practices and support associated with the grid are discussed. Finally, the paper emphasizes questions that need to be answered in order to contribute to the future development of the grid. Copyright © 2006 John Wiley & Sons, Ltd.     

Tables of a Truncated Standard Normal Distribution: A Doubly Truncated Case

As an extension to the singly truncated case, this article further examines a doubly truncated normal distribution. In this article, we consider both symmetric and asymmetric cases with two truncation points on the left and the right, and develop the tables of a truncated mean, a truncated variance, and a cumulative probability.     

Novel Route to Propylene Carbonate: Selective Synthesis from Propylene Glycol and Carbon Dioxide

High surface area zirconium phosphate in an amorphous phase exhibits high activities for water-related reactions such as hydrolysis of ethyl acetate and esterification of acetic acid with ethanol. The zirconium phosphate is insoluble during the reaction, is recoverable by simple filtration, and can be reused at least five times without any treatment.     

Volume contraction behaviour of binary solid-liquid fluidized beds

Contrary to the widely held notion that the total bed height of a binary solid fluidized bed will be the sum of heights of the two individual mono-component beds fluidized at the same velocity, significant negative deviations have been observed in our experimental investigation. The negative deviations, signifying a contraction of the total volume of the binary solid fluidized bed, could sometimes be as high as 25% of the actual volume. The volume contraction has been found to depend mainly upon the degree of solids mixing prevailing in the bed irrespective of whether it is fully fluidized or not. The composition of the binary solid fluidized was another important factor that influenced the contraction behaviour of the bed besides the size ratio of the two constituent solid species of the binary present in the bed.     

The effects of aqueous extraction on the performance of wheat bran in bread

Wheat bran was sieved into coarse, medium and fine fractions prior to extraction with tap water. Bran, bran extract and bran residue were analysed for moisture, protein, fat, ash, pentosan and phytic acid. Farinograph measurements and baking tests showed maximum dough resistance and loaf volume of a white flour were both increased by the addition of the residue. Both these parameters were substantially decreased by bran extract and, to a lesser degree, by the bran itself. These findings were common amongst the size fractions although the residue from the coarse bran had the greatest effect on loaf volume and dough properties.     

Extraction of Fe(III) from phosphoric acid by HDDNSA

A study was conducted on the stoichiometry of the reaction that takes place on the extraction of ferric ions by didodecyl naphthalene sulphonic acid (HDDNSA) from phosphoric acid solutions. The experimental results were numerically analyzed by nonlinear regression. It was found that ferric forms two compounds with HDDNSA, namely Fe(DDNSA)₃, and FeHPO₄-DDNSA. The values of the equilibrium constants of the reactions involved were also calculated.     

Analysis and test procedures for NOR flash memory defects

Widespread use of non-volatile memories, especially flash memories, in diverse applications such as in mobile computing and system-on-chip is becoming a common place. As a result, testing them for faults and reliability is drawing considerable interest of designers and researchers. One of the most predominant failure modes for which these memories must be tested is called disturb faults. In this paper, we first analyze different defects that are responsible for disturb faults using a 2-dimension device simulator. We determine the impact of various defects on cell performance and develop a methodology based on channel erase technique to detect these defects. Our tests are efficient and can be converted to march tests prevalently used to test memories. We also propose a very low cost design-for-testability approach that can be used to apply the test technique developed in this paper.     

Mathematical model evaluating for degradation of azo dye in contaminated water by UV/persulfate process

In the present study, the photooxidative degradation of Acid Red 14 (AR 14) was investigated in the UV/persulfate process, and the results of the degradation rate of AR 14 were parametrically represented by ordinary differential equations to find mathematical model for the degradation rate of AR 14 in this process. Our experimental observations led to a model for AR 14 degradation in the UV/persulfate system that could be used to predict removal efficiency by changes of S₂O₈²⁻ (X₁) and dye concentration (X₂), pH (X₃), temperature (X₄) and also distance of UV lamp from solution (X₅). It was found that persulfate and dye concentrations were the most important parameters for AR 14 degradation rate. Moreover, the results showed that the degradation rate was in good agreement with the first-order kinetics for all the parameter values studied. Moreover, the results of the mathematical model agree well with the experimental values (R² = 0.96). Our findings in this study showed that degradation efficiency of UV/S₂O₈²⁻ process for AR 14 was obtained as 98%. Therefore, this model could be applicable before scaling up the AR 14 degradation using UV/persulfate process.