A microstructural evaluation of friction stir welded 7075 aluminum rolled plate heat treated to the semi-solid state

Two rolled plates of 7075 aluminum alloy were used as starting material. The plates were welded using a simultaneous double-sided friction stir welding (FSW) process. One way of obtaining feedstock materials for Semi-solid processing or thixoforming is via deformation routes followed by partial melting in the semi-solid state. As both the base plate materials and the friction weld area have undergone extensive deformation specimens were subjected to a post welding heat-treatment in the semi-solid range at a temperature of 628 °C, for 3 min in order to observe the induced microstructural changes. A comparison between the microstructural evolution and mechanical properties of friction stir welded plates was performed before and after the heat-treatment in the Base Metal (BM), the Heat Affected Zone (HAZ), the Thermomechanically Affected Zone (TMAZ) and the Nugget Zone (NZ) using optical microscopy, Scanning Electron microscopy (SEM) and Vickers hardness tests. The results revealed that an extremely fine-grained structure, obtained in the NZ after FSW, resulted in a rise of hardness from the BM to the NZ. Furthermore, post welding heat-treatment in the semi-solid state gave rise to a consistent morphology throughout the material which was similar to microstructures obtained by the thixoforming process. Moreover, a drop of hardness was observed after heat treatment in all regions as compared to that in the welded microstructure

Food habits of Oxygaster bacaila (Ham.) from Kaptai Lake, Bangladesh

Gut contents of 120 Oxygaster bacaila fmm Kaptai Lake were studied. Index of preponderance (IP) indicated that 0. bacaila consumed highest amount of Insects (35.89%) and thus occupied the first position among the food items. Zooplankton (Rmifera and crustacea 31.79%) and the other food items found in the guts were algae (Chlorophyceae, Bacillariophyceae, Euglenophyceae and Cyanophyceae 24.51%). From the analysis of gut contents, this fish might be considered as omnivore as it consumed both animal and plant foods with higher preference for animal food. The feeding intensity of this fish is fairly high. Total length (TL) versus gut length (GL) relationship and their ratio were found to be GL = 0.57663 TLL04801 (r = 0.9963) and TL: GL = l: 0.7086 respectively

Using Bayesian Model Averaging (BMA) to calibrate probabilistic surface temperature forecasts over Iran

Using Bayesian Model Averaging (BMA), an attempt was made to obtain calibrated probabilistic numerical forecasts of 2-m temperature over Iran. The ensemble employs three limited area models (WRF, MM5 and HRM), with WRF used with five different configurations. Initial and boundary conditions for MM5 and WRF are obtained from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) and for HRM the initial and boundary conditions come from analysis of Global Model Europe (GME) of the German Weather Service. The resulting ensemble of seven members was run for a period of 6 months (from December 2008 to May 2009) over Iran. The 48-h raw ensemble outputs were calibrated using BMA technique for 120 days using a 40 days training sample of forecasts and relative verification data. <br><br> The calibrated probabilistic forecasts were assessed using rank histogram and attribute diagrams. Results showed that application of BMA improved the reliability of the raw ensemble. Using the weighted ensemble mean forecast as a deterministic forecast it was found that the deterministic-style BMA forecasts performed usually better than the best member's deterministic forecast

Seed Germination, Seedling Growth and Enzyme Activity of Wheat Seed Primed under Drought and Different Temperature Conditions

The study aimed was to determine the effects of drought stress (0, -4, -8, -12 bar) and osmopriming (-15 bar PEG 6000 for 15 at 24 h) on seed germination, seedling growth and enzyme activity at different temperatures were assessed in the laboratory for wheat. Results showed that the highest germination percentage (GP) (94.33%), normal seedling percentage (NSP) (92%), germination index (GI) (44.85) and seedling length (11.03 cm) were attained from osmo-priming in control conditions. Therefore, seed priming with PEG 6000 significantly (p≤ 0.01) increased germination characteristics as compared to the unprimed seeds under drought stress. Also, osmopriming increased catalase (CAT) and ascorbate peroxidase (APX) as compared to the unprimed

Aproksimasi Variasional untuk Soliton Onsite pada Persamaan Schrödinger Nonlinier Diskrit Kubik-Kuintik

Persamaan Schrödinger nonlinier diskrit (SNLD) kubik-kuintik merupakan persamaan beda-diferensial yang memiliki eksistensi solusi soliton. Pada artikel ini hampiran solusi soliton stasioner dengan konfigurasi bertipe onsite pada persamaan SNLD kubik-kuintik untuk limit anti-continuum ditentukan dengan menggunakan metode aproksimasi variasional (AV). Fungsi penduga yang diusulkan berbentuk eksponensial dengan tiga parameter variasional. Solusi AV yang diperoleh selanjutnya diperiksa validasinya dan dibandingkan dengan solusi numerik. Hasil yang diperoleh menunjukkan bahwa solusi AV valid dan mempunyai kesesuaian yang sangat baik dengan solusi numerik

Phase transition in Schwarzschild-de Sitter spacetime

Using a static massive spherically symmetric scalar field coupled to gravity in the Schwarzschild-de Sitter (SdS) background, first we consider some asymptotic solutions near horizon and their local equations of state(E.O.S) on them. We show that near cosmological and event horizons our scalar field behaves as a dust. At the next step near two pure de-Sitter or Schwarzschild horizons we obtain a coupling dependent pressure to energy density ratio. In the case of a minimally couplling this ratio is -1 which springs to the mind thermodynamical behavior of dark energy. If having a negative pressure behavior near these horizons we concluded that the coupling constant must be $\xi<{1/4}$ >. Therefore we derive a new constraint on the value of our coupling $\xi$ . These two different behaviors of unique matter in the distinct regions of spacetime at present era can be interpreted as a phase transition from dark matter to dark energy in the cosmic scales and construct a unified scenario.Comment: 7 pages,no figures,RevTex, Typos corrected and references adde

The image of nursing, as perceived by Iranian male nurses

The stereotypical public image of nursing is a major concern for male nurses around the world. In this study, we explored how Iranian male nurses perceived the public view of nurses, and their perceptions of themselves. A qualitative descriptive design and content analysis were used to obtain data from 18 purposely-selected male hospital nurses with a baccalaureate nursing degree in Tabriz, Iran. Semistructured interviews were conducted and analyzed. Two main themes emerged: (i) the outsider's view of nursing, which referred to the participants' perceptions of their public image; and (ii) the insider's view, which related to the male nurses' perceptions of themselves. Results included personal transition into a positive professional self-image through the educational process, and continued public perception of nursing as a female profession ill-suited for a man. Strategies to improve the insider's and outsider's views of nursing are listed to help recruit and retain more Iranian male nurses

Glycogen Phosphomonoester Distribution in Mouse Models of the Progressive Myoclonic Epilepsy, Lafora Disease

Glycogen is a branched polymer of glucose that acts as an energy reserve in many cell types. Glycogen contains trace amounts of covalent phosphate, in the range of 1 phosphate per 500–2000 glucose residues depending on the source. The function, if any, is unknown, but in at least one genetic disease, the progressive myoclonic epilepsy Lafora disease, excessive phosphorylation of glycogen has been implicated in the pathology by disturbing glycogen structure. Some 90% of Lafora cases are attributed to mutations of the EPM2A or EPM2B genes, and mice with either gene disrupted accumulate hyperphosphorylated glycogen. It is, therefore, of importance to understand the chemistry of glycogen phosphorylation. Rabbit skeletal muscle glycogen contained covalent phosphate as monoesters of C2, C3, and C6 carbons of glucose residues based on analyses of phospho-oligosaccharides by NMR. Furthermore, using a sensitive assay for glucose 6-P in hydrolysates of glycogen coupled with measurement of total phosphate, we determined the proportion of C6 phosphorylation in rabbit muscle glycogen to be ∼20%. C6 phosphorylation also accounted for ∼20% of the covalent phosphate in wild type mouse muscle glycogen. Glycogen phosphorylation in Epm2a−/− and Epm2b−/− mice was increased 8- and 4-fold compared with wild type mice, but the proportion of C6 phosphorylation remained unchanged at ∼20%. Therefore, our results suggest that C2, C3, and/or C6 phosphate could all contribute to abnormal glycogen structure or to Lafora disease