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  • Author: Poonam Verma x
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Abstract

The full potential linear augmented wave method has been used for an ab-initio study of structural, electronic and high pressure phase transformation features of ZnAl2Se4. The exchange and correlation potential (XC) was calculated using the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and the modified GGA due to Engel–Vosko (EV-GGA). The geometry optimization was performed by calculating the total energy as a function of the three variables u, c/a and V. Using the sets of data obtained we determined the equilibrium volume, V 0, the bulk modulus, B 0, and the pressure derivative of the bulk modulus, B 0′. The results show that ZnAl2Se4 is a direct wide band gap semiconductor at ambient conditions (P = 0, T = 0). With increasing hydrostatic pressure of the unit cell (i.e., with decreasing size) both the direct (Γ—Γ) and the indirect (Γ—H) energy gaps first increase and at a pressure of 9.2 GPa both gaps become equal and start decreasing as the pressure increases further but with a change in the nature of the energy band gap from direct to indirect. With increasing pressure a transition from tetragonal to spinel phase has been observed at a pressure of 3 GPa.

Abstract

Background: Acquired immunodeficiency syndrome (AIDS) is a major health problem worldwide. The number of infected people is increasing daily. Knowledge and awareness toward prevention and control of the disease is necessary among both educated and illiterate people.

Objective: This study is aimed at assessing the knowledge and awareness about human immunodeficiency virus (HIV)/AIDS among undergraduate students studying in a technical institute in Gorakhpur, Uttar Pradesh, India.

Methods: A community-based cross-sectional study was conducted among youths aged 15–30 years studying in a technical institution in Gorakhpur. Data were collected using a semistructured questionnaire developed with the help of existing literature, from 250 participants (students).

Results: The main source of information was the television; knowledge about the difference between HIV/AIDS was satisfactory. The findings showed that the knowledge about modes of prevention (blood checkup, needle/syringe sterilization) was satisfactory. There were several misconceptions about the modes of transmission of the disease, such as through mosquito bites, eating/drinking, and kissing.

Conclusion: The knowledge of the study population was satisfactory, and there is a need for innovation and comprehensive education to impart better knowledge and understanding about HIV/AIDS.

The determination of fluoride from diverse matrices at front and back end of nuclear technology and some studies from this laboratory on optimizations of different experimental parameters differing with multiple fuels and reactor materials, have been reviewed. The most useful techniques such as fluoride ion selective electrode (F-ISE) and ion-chromatography (IC) widely adopted as routine methods for fluoride determination in nuclear industry have been discussed. The effect of various buffer strengths on the response of the fluoride ion selective electrode has been examined. The ion chromatographic studies on mobile phase concentration, medium of sample, sample injection volume etc. to get distinct fluoride peak within optimum time in presence of other anionic species in diverse concentrations have been reported. The results of various sample matrices such as UO2, PuO2, (U,Pu)O2, Pu-alloy, thoria, zircaloy, slag, HLLW, LLLW etc., analyzed after matrix separation using pyrohydrolysis setup, for both solid and liquid samples and without matrix separation by masking potentially interfering ions of liquid samples, have been presented.