561 research outputs found

    Electronic structure of MgB<SUB>2</SUB>

    Get PDF
    Results of ab initio electronic structure calculations on the compound MgB2 using the FPLAPW method employing GGA for the exchange-correlation energy are presented. Total energy minimization enables us to estimate the equilibrium volume, c/a ratio and the bulk modulus, all of which are in excellent agreement with experiment. We obtain the mass enhancement parameter by using our calculated D (E F) and the experimental specific heat data. The T c is found to be 24.7 K

    On hydrogen bond correlations at high pressures

    Full text link
    In situ high pressure neutron diffraction measured lengths of O H and H O pairs in hydrogen bonds in substances are shown to follow the correlation between them established from 0.1 MPa data on different chemical compounds. In particular, the conclusion by Nelmes et al that their high pressure data on ice VIII differ from it is not supported. For compounds in which the O H stretching frequencies red shift under pressure, it is shown that wherever structural data is available, they follow the stretching frequency versus H O (or O O) distance correlation. For compounds displaying blue shifts with pressure an analogy appears to exist with improper hydrogen bonds.Comment: 12 pages,4 figure

    Band theory analysis of shock velocity-particle velocity relations for metals

    Get PDF
    The systematics of the shock constants in shock velocity-particle velocity relations for metals have been examined by energy band theory methods. The causes of non-linearity of this relation at high pressure are discussed in terms of s ⇌d electron transfer

    On the nature of the dhcp to fcc transition under pressure in Pr and Pr-Th alloys

    Get PDF
    The results of electrical resistance (R), thermoelectric power (TEP) and X-ray diffraction measurements on praseodymium (Pr) and its alloys with thorium under pressure are reported. The maximum inR vsP curve exhibited by Pr persists only in the dhcp phase of PrTh alloy. X-ray measurements confirmed that in the alloys also the maximum inR vsP curve is due to the dhcp → fcc transition. Thus the behaviour of Pr and Pr-Th alloys is different from that of La and its alloys with Ce and Th where the maximum in theR vsP curve is electronic in origin and is exhibited by the dhcp, fcc and dist fcc phases

    An innovative approach to measure skill about artificial insemination in buffaloes

    Get PDF
    Data pertaining to 3 trainings on artificial insemination (AI) were analyzed and 44 farmers constituted as the study sample. The respondents selected for the study were those who had earlier exposure to AI as they were doing it in the field but needed further refinement of skills. To study skill development in AI, the process was broken into different steps, viz. estrus check, washing of buffaloes, thawing, loading, passage of AI gun and important precautions. Each step was assigned scores of 10, 10, 10, 40, 10 and 20, respectively, by seeking the response from 30 scientists working in the Institute and LUVAS (Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar). Scores were assigned to each step and summated to arrive at final score of a respondent based on their skill of each step. Thus, individual pre- and post-training scores attained by the respondents during these training programs were calculated. Mean pre-training score of respondents was 51.36 while their post-training score was 67.73 out of 100. Thus, scores of respondents were worked for the AI process- before and after the training program. The difference between the pre- and post-training scores of the respondents was 6.56 (z=6.56), which was significant. Thus, significant gain in skill of the respondents who had undergone this training was observed

    The extreme positive Indian Ocean Dipole of 2019 and associated Indian summer monsoon rainfall response

    Get PDF
    The positive Indian Ocean Dipole (IOD) event in 2019 was among the strongest on record, while the Indian Summer monsoon (ISM) was anomalously dry in June then very wet by September. We investigated the relationships between the IOD, Pacific sea surface temperature (SST) and ISM rainfall during 2019 with an atmospheric general circulation model forced by observed SST anomalies. The results show that the extremely positive IOD was conducive to a wetter-than-normal ISM, especially late in the season when the IOD strengthened and was associated with anomalous low-level divergence over the eastern equatorial Indian Ocean and convergence over India. However, a warm SST anomaly in the central equatorial Pacific contributed to low level divergence and decreased rainfall over India in June. These results help to better understand the influence of the tropical SST anomalies on the seasonal evolution of ISM rainfall during extreme IOD events

    Investigation of structure and hydrogen bonding of super-hydrous phase B (HT) under pressure using first principles density functional calculations

    Get PDF
    High pressure behaviour of superhydrous phase B(HT) of Mg10Si3O14(OH)4 (Shy B) is investigated with the help of density functional theory based first principles calculations. In addition to the lattice parameters and equation of state, we use these calculations to determine the positional parameters of atoms as a function of pressure. Our results show that the compression induced structural changes involve cooperative distortions in the full geometry of the hydrogen bonds. The bond bending mechanism proposed by Hofmeister et al [1999] for hydrogen bonds to relieve the heightened repulsion due to short H--H contacts is not found to be effective in Shy B. The calculated O-H bond contraction is consistent with the observed blue shift in the stretching frequency of the hydrogen bond. These results establish that one can use first principles calculations to obtain reliable insights into the pressure induced bonding changes of complex minerals.Comment: 16 pages, 4 figure

    Air pollution perception in ten countries during the COVID-19 pandemic

    Get PDF
    As largely documented in the literature, the stark restrictions enforced worldwide in 2020 to curb the COVID-19 pandemic also curtailed the production of air pollutants to some extent. This study investigates the perception of the air pollution as assessed by individuals located in ten countries: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the USA. The perceptions towards air quality were evaluated by employing an online survey administered in May 2020. Participants (N = 9394) in the ten countries expressed their opinions according to a Likert-scale response. A reduction in pollutant concentration was clearly perceived, albeit to a different extent, by all populations. The survey participants located in India and Italy perceived the largest drop in the air pollution concentration; conversely, the smallest variation was perceived among Chinese and Norwegian respondents. Among all the demographic indicators considered, only gender proved to be statistically significant

    Potential and Challenges of Rainfed Farming in India

    Get PDF
    India ranks first in rainfed agriculture globally in both area (86 Mha) and the value of produce. Rainfed regions in India contribute substantially toward food grain production including 44% of rice, 87% of coarse cereals (sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), maize (Zea mays)), and 85% of food legumes, 72% of oilseeds, 65% of cotton, and 90% of minor millets. Overall, the rainfed areas produce 40% of the food grains, support two-thirds of the livestock population, and are critical to food security, equity, and sustainability..

    Report of the Task Force on Enhancing technology use in agriculture insurance

    Get PDF
    Pradhan Mantri Fasal Bima Yojana (PMFBY) is a flagship scheme of the Government of India to provide insurance coverage and financial support to farmers in the event of failure of any of the notified crops, unsown area and damage to harvest produce as a result of natural calamities, pests and diseases to stabilise the income of farmers, and to encourage them to adopt modern agricultural practices. The scheme is a considerable improvement over all previous insurance schemes in India and is heavily subsidised by the state and central governments. The scheme aims to cover 50 percent of the farming households within next 3 years. During its implementation in the last one season, several challenges relating to enrolment, yield estimation, loss assessment, and claim settlement were reported by farmers, insurance companies as well as the state governments. It was also noted that several technological opportunities existed for possibly leveraging support to the Indian crop insurance program for enhanced efficiency and effectiveness. NITI Aayog of the Government of India, therefore, constituted a Task Force to deliberate on this subject and identify such potential opportunities. This report summarises the recommendations of the Task Force. The Task Force constituted to address the issue of technology support to crop insurance comprised the following 5 sub-groups: (1) Remote Sensing & Drones; (2) Decision Support Systems, Crop Modelling & Integrated Approaches; (3) IT/ICT in Insurance; (4) Crop Cutting Experiments (CCEs); and (5) Technologies for Livestock and Aquaculture Insurance. Each sub-group had several discussions with experts in the respective areas, and submitted draft reports. More than 100 experts related to professional research agencies, insurance industry, banks, and the government contributed to these discussions. Technological options available in the country and abroad were considered by all groups. The Task Force together with the sub-groups then deliberated on key issues and formulated its recommendations as presented in this report. During the discussions it was realised that there were many administrative and institutional issues that needed to be addressed in PMFBY. However, the focus of the Task Force was on its main mandate, technology use in crop insurance. We hope these recommendations would help the Indian crop insurance sector take full advantage of the technological options suggested so as to increase its efficacy and effectiveness leading to reduced agrarian distress in the country
    corecore