INVERSE HEAT CONDUCTION PROBLEM IN A SOLID SPHERE AND ITS THERMAL STRESSES

This paper discusses the solution of an inverse heat conduction problem of one dimensional temperature distribution and stress field for a solid sphere. The sphere is subjected to arbitrary temperature within it under unsteady state condition. Initially the sphere is maintained at constant temperature. The governing heat conduction equation has been solved by the integral transform technique. The temperature distribution,unknown temperature and thermal stresses are obtained in the form of trigonometric function. The numerical example is presented for Titanium alloy to discuss the results

Control of Switching Characteristics of Silicon-based Semiconductor Diode Using High Energy Linear Accelerator

This paper reports control of switching characteristics of silicon-based semiconductor diode using electron beam produced using linear accelerator. Conventionally, p-n junction chips of diode are exposed to gamma rays from a radioactive source or electron beam from a microtron, depending upon the required level of correction. High energy linear accelerators featuring simultaneous exposure of multiple chips are recent advancements in radiation technology. The paper presents the results of the radiation process using a 10 MeV linear accelerator as applied in industrial manufacturing of a high voltage diode (2600 V). The achieved values of reverse recovery time were found to be within the design limits. The suitability of the new process was verified by constructing the trade-off curve between the switching and conduction parameters of the diode for the complete range using large number of experimental samples. The paper summarizes the advantages of the new process over the conventional methods specifically with reference to industrial requirements. The developed process has been successfully implemented in semiconductor manufacturing. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3099

Use of >100,000 NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium whole genome sequences improves imputation quality and detection of rare variant associations in admixed African and Hispanic/Latino populations

Most genome-wide association and fine-mapping studies to date have been conducted in individuals of European descent, and genetic studies of populations of Hispanic/Latino and African ancestry are limited. In addition, these populations have more complex linkage disequilibrium structure. In order to better define the genetic architecture of these understudied populations, we leveraged >100,000 phased sequences available from deep-coverage whole genome sequencing through the multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) program to impute genotypes into admixed African and Hispanic/Latino samples with genome-wide genotyping array data. We demonstrated that using TOPMed sequencing data as the imputation reference panel improves genotype imputation quality in these populations, which subsequently enhanced gene-mapping power for complex traits. For rare variants with minor allele frequency (MAF) 86%. Subsequent association analyses of TOPMed reference panel-imputed genotype data with hematological traits (hemoglobin (HGB), hematocrit (HCT), and white blood cell count (WBC)) in ~21,600 African-ancestry and ~21,700 Hispanic/Latino individuals identified associations with two rare variants in the HBB gene (rs33930165 with higher WBC [p = 8.8x10-15] in African populations, rs11549407 with lower HGB [p = 1.5x10-12] and HCT [p = 8.8x10-10] in Hispanics/Latinos). By comparison, neither variant would have been genome-wide significant if either 1000 Genomes Project Phase 3 or Haplotype Reference Consortium reference panels had been used for imputation. Our findings highlight the utility of the TOPMed imputation reference panel for identification of novel rare variant associations not previously detected in similarly sized genome-wide studies of under-represented African and Hispanic/Latino populations

Numerical simulation and experimental validation of arc welding of DMR-249A steel

The thermo-mechanical attributes of DMR-249A steel weld joints manufactured by shielded metal arc welding (SMAW) and activated gas tungsten arc welding (A-GTAW) processes were studied using Finite Element Model (FEM) simulation. The thermal gradients and residual stresses were analyzed with SYSWELD software using double ellipsoidal heat source distribution model. The numerically estimated temperature distribution was validated with online temperature measurements using thermocouples. The predicted residual stresses profile across the weld joints was compared with the values experimentally measured using non-destructive techniques. The measured and predicted thermal cycles and residual stress profile was observed to be comparable. The residual stress developed in double sided A-GTAW joint were marginally higher in comparison to five pass SMAW joint due to phase transformation associated with high heat input per weld pass for A-GTAW process. The present investigations suggest the applicability of numerical modeling as an effective approach for predicting the thermo-mechanical properties influenced by welding techniques for DMR-249A steel weld joints. The tensile, impact and micro-hardness tests were carried to compare the welds. Considering benefits of high productivity and savings of labor and cost associated with A-GTAW compared to SMAW process, the minor variation in residual stress build up of A-GTAW joint can be neglected to develop A-GTAW as qualified alternative welding technique for DMR-249A steel

A Morphometric Study of Lumbar Spine Pedicles in Nepalese Population

Background and Objective: In this observational study, morphometric data were obtained and analyzed by taking plain x-rays in various age groups to establish the morphometric values in Nepalese population. Methods: All the pedicle dimensions were measured by taking plain x-ray AP (Antero-posterior) and Lateral view of the lumbar spine in 246 Nepalese of different age groups. Pedicle diameters (Vertical and Horizontal) and interpedicular distance were measured in AP radiographs and sagittal angle was measured in the lateral radiographs. Differences between mean dimensions of pedicles of male and female of various age groups were tested by using ANOVA, independent t-test was used to test the individual mean dimensions. Results: Mean values of the pedicle dimensions were found as: Horizontal diameter (L1=7.17mm, L2=7.26mm, L3= 9.50mm, L4= 10.57mm and L5=11.3mm), Vertical diameter (L1= 15.00mm, L2=15.28mm, L3=15.21mm, L4=13.44mm and L5= 12.59mm), Interpedicular distance (L1= 25.54mm, L2 =27.03mm, L3 = 27.70mm, L4 =28.62mm and L5= 31.29mm) and the sagittal angle (L1=17.83degree, L2=15.7degree, L3= 15.91degree, L4=13.94degree, and L5=12.97degree) respectively. Conclusions: Values of pedicle dimensions found in Nepalese population by this study can be guidelines for the transpedicular procedure and for further research activities. DOI: http://dx.doi.org/10.3126/jcmsn.v10i4.12972 JCMS Nepal 2014; 10(4):12-17</p

Importance of Community Forestry Funds for Rural Development in Nepal

Nepal&#8217;s Community Forestry (CF) process has implied the devolution of powers to collect, retain, and redistribute forest revenue from community forests products. This study contributes to our knowledge about these important aspects of CF by presenting an analysis of the dynamic pattern of income and expenditure of 43 randomly selected Community Forestry User Groups (CFUGs) from Kaski, Nepal. Results show that CFUG three-year average annual income accounts NRs 216,225 (1 US$ = NRs.114) and is highly skewed towards a few wells off CFUGs; the high-and-low average annual income of one-third of CFUGs in the sample ranges from NRs. 33,116 to NRs 502,363. Timber income and user&#8217;s contribution constitute the most important sources of income, comprising 40% and 25% respectively. The rural development investments of CFUG income are also highly variable and are shaped by income size of CF, and the other socio-political factors such as the number of households, distance to market, infrastructure status, and contextual factors. Overall, 44% of the CFUG income is invested in community development and 37% in forest conservation. Investment in community development increases with rising income. Accordingly, results presented here provide insights to promote community forests to generate more income which, indeed, could be a vehicle for community development as it appears in the mid-hills of Nepal

Insights on the Impacts of Hydroclimatic Extremes and Anthropogenic Activities on Sediment Yield of a River Basin

Streamflow and sediment flux variations in a mountain river basin directly affect the downstream biodiversity and ecological processes. Precipitation is expected to be one of the main drivers of these variations in the Himalayas. However, such relations have not been explored for the mountain river basin, Nepal. This paper explores the variation in streamflow and sediment flux from 2006 to 2019 in central Nepal&rsquo;s Kali Gandaki River basin and correlates them to precipitation indices computed from 77 stations across the basin. Nine precipitation indices and four other ratio-based indices are used for comparison. Percentage contributions of maximum 1-day, consecutive 3-day, 5-day and 7-day precipitation to the annual precipitation provide information on the severity of precipitation extremeness. We found that maximum suspended sediment concentration had a significant positive correlation with the maximum consecutive 3-day precipitation. In contrast, average suspended sediment concentration had significant positive correlations with all ratio-based precipitation indices. The existing sediment erosion trend, driven by the amount, intensity, and frequency of extreme precipitation, demands urgency in sediment source management on the Nepal Himalaya&rsquo;s mountain slopes. The increment in extreme sediment transports partially resulted from anthropogenic interventions, especially landslides triggered by poorly-constructed roads, and the changing nature of extreme precipitation driven by climate variability