Corrosion-Fatigue Behavior of Aluminum Alloy 5083-H131 Sensitized at 448?K (175?°C)

The fatigue crack growth behavior of aluminum alloy 5083-H131 has been systematically studied as a function of degree of sensitization for aging at 448?K (175?°C). Fatigue crack growth rates were measured at load ratios of 0.1 and 0.85, in vacuum, air, and a corrosive aqueous environment containing 1?pct NaCl with dilute inhibitor. Sensitization does not affect the fatigue crack growth behavior of Al 5083-H131 significantly in vacuum or air, at low- or high-load ratio. For high-load ratio, in the 1?pct NaCl+inhibitor solution, the threshold drops by nearly 50?pct during the first 200?hours of aging, then it degrades more slowly for longer aging times up to 2000?hours. The change in aging behavior at approximately 200?hours seems to be correlated with the transition from partial coverage of the grain boundaries by ?? Al₃Mg₂ phase, to continuous full ?? coverage. ASTM G-67 mass loss levels below approximately 30?mg/cm² do not exhibit degraded corrosion-fatigue properties for R?=?0.85, but degradation of the threshold is rapid for higher mass loss levels.     

Synthesis,characterization and corrosion performance evaluation of DDR membrane for H2 separation from HI decomposition reaction

An all silica DDR (deca dodecasil rhombohedral) zeolite membrane with dense, interlocked structure has been developed for separation of H₂ from HI/I₂ mixture of HI decomposition reaction. In this work, the DDR zeolite membrane was synthesized on the seeded clay-alumina substrate within 5 days. The seeds were synthesized by sonication mediated hydrothermal process within short crystallization time which enhanced the nucleation for the membrane growth. The synthesized membranes along with seed crystals were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDAX). The selectivity of hydrogen with respect to CO₂ and Ar was evaluated by single gas permeation studies at room temperature. The tests for corrosion resistance were carried out upto 120 h with both support and DDR membrane at 130 °C which confirmed the stability of membrane under the harsh HI/I₂ environment.     

A Gravitational Search Algorithm Based Static VAR Compensator Switching Function Optimization Technique for Minimum Harmonic Injection

Switching function optimization for minimum source harmonic injection for a static VAR compensator is presented. The static VAR compensator is configured with a fixed capacitor and insulated-gate bipolar transistor controlled reactor. The switching function is optimized for minimum source harmonic injection considering the desired fundamental voltage across load terminals. A gravitational search algorithm is employed for this purpose. It is observed that the proposed switching scheme with two different switching angles per half-cycle provides lower source harmonic injection compared to conventional switching, hence improving the source current harmonics. The switching angles are computed off-line using the gravitational search algorithm for varying modulation indices considering the minimum total harmonic distortion of the reactor voltage. The switching angles are stored in a processor as a function of the modulation index for on-line application using a piecewise mixed model approximation technique for low memory usage. It is observed that the proposed switching improves the source current total harmonic distortion on an average of 4 to 5% over most of the operating range compared to conventional switching without optimization. Various simulation and experimental results are presented on different loads to validate the proposed concept.     

Application of molecular identification tools for Lactobacillus, with a focus on discrimination between closely related species: A review

Lactobacillus is among the most important GRAS food lactic acid bacteria, with nearly 140 species at present, mostly of industrial importance. Being part of the natural flora of a range of food products like raw milk, fermented dairy products, fruits, vegetables, meat products they also serve as starters for a number of fermented food products either to enhance the quality or to add health benefits. These groups of economically important species are often alike in phenotypic and physiological characteristics, probably due to their co-evolution in the same ecological niches; hence they are difficult to be differentiated. This demands advanced methods for their proper identification and characterization. With the advancement of molecular biology, a range of DNA-based molecular techniques has replaced the largely cumbersome phenotypic methods. This review summarizes the various molecular techniques available for detection and identification within the genus Lactobacillus, with special emphasis on the four groups of closely resembling species: L. casei group, L. acidophilus group, L. delbrueckii subspecies, and L. plantarum group. This review also provides insights into current trends for alternative molecular markers other than 16S rRNA to resolve the ambiguity within phylogenetically close species in the genus Lactobacillus.     

A joint economic-lot-size model for purchaser and vendor in fuzzy sense

This paper investigates a group of computing schemas for joint economic lot size as fuzzy values of the economic lot size model for purchaser and vendor. We express the fuzzy order quantity/production lot size for the purchaser/vendor as the normal triangular fuzzy number (q₁, q₀, q₂) and then we solve the aforementioned optimization problem under the condition 0 < q₁ < q₀ < q₂. We find that, after defuzzification, the joint total relevant cost is slightly higher than in the crisp model.     

Growth, optical transmission and X-ray photoemission studies of BaB2O4 single crystals

Beta barium borate (-BBO) crystals have been grown by the top seeded solution growth technique (TSSG) using Na₂O as a flux. The crystals exhibited high transparency and the absence of inclusions and found to have sodium contamination in the range 150 to 230 p.p.m. The effect of this contamination on some crystal properties of interest has been investigated. The presence of impurities causes optical absorption below 550 nm in BBO crystals of both and -phases. X-ray photo emission spectroscopy (XPS) measurements performed on these crystals show that sodium gives rise to a measurable shift in the binding energies of the constituent ions. Further, the results show that Na⁺ ions enter into the lattice substitutionally and provide charge trapping sites close to the band edge.     

Interleukin-6-mediated autocrine growth promotion in human glioblastoma multiforme cell line U87MG

Human glioblastoma multiforme cell lines, brain tumor biopsy tissue, and normal human fetal brain synthesize interleukin (IL)-6 and IL-6 receptor (IL-6R). Neither of these is expressed in human neurons or neuroblastoma cell lines in culture. Astrocytes from fetal brain grown in culture retain the ability to synthesize IL-6 but do not express IL-6R as inferred from RT-PCR and Southern blot studies. Coexpression of IL-6 and IL-6R in the glioblastoma cell line U87MG is confirmed by immunofluorescence staining. Both specific monoclonal antibodies against IL-6 and IL-6R and antisense oligonucleotide to IL-6 mRNA inhibit the growth of U87MG cells in culture, suggesting the existence of a functional autocrine growth loop. Anti-IL-6 antibodies also inhibit the growth of glioblastoma cell lines U373 and U118. The expression of IL-6 by human fetal astrocytes in culture is highly suggestive of its role as an oncofetal protein responsible for rapid proliferation of fetal and tumor cells but not cells of adult brain.     

Responses of American readers to visual aspects of a mid-sizedJapanese company's annual report: a case study

American document design process models reflect the assumption that comprehension and usability are the most important characteristics of effective documents, but it is increasingly evident that other cultures value other communicative features of documents and that purposes and intentions vary across cultures. This case study examines the responses of four sets of American readers (three sets familiar with American document design research and practice and one set of content specialists-engineers by training) to the visual aspects of an annual report. The original document was prepared for a mid-sized Japanese corporation and published and distributed in Japan; the American version is an almost literal translation of the original document from Japanese to English, with no changes in visuals, graphic design or format. Protocol analyses of readers' responses revealed distinct patterns of expectations and preferences based on (1) cultural biases, (2) degree of familiarity with the American document design model, and (3) ignorance of Japanese culture and corporate communicative practices. This study raises questions about the effectiveness in terms of cultural sensitivity of what we have called the “American” document design process model and usability testing procedures, and calls for extensive collaborative research designed to describe and analyze current practice in international settings     

Isobaric vapour-liquid equilibria of the ternary system hexane-benzene-sulpholane

Isobaric vapour-liquid equilibria for the ternary system hexane-benezene-sulpholane have been determined at 760 mmHg pressure. The data have been compared with those calculated using the NRTL equation. The NRTL constants obtained from the literature were evaluated from ternary liquid-liquid equilibrium data for this system. The agreement between experimental and calculated values is reasonable.