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[en] Single phase perovskite 0.9Pb(Mg1/3Nb2/3)O3-0.1(PbTiO3) ceramics were prepared using the columbite precursor method after optimizing the synthesis conditions. X-ray diffraction (XRD) studies were carried out to verify the phase formation at each processing step. Scanning electron microscopy (SEM) was employed to observe the microstructure of the sintered ceramics. Impedance and modulus spectroscopic data were used to gain an insight into the electrical properties of the samples and with a view to observing the relaxations in them
[en] The X-ray diffraction intensities of Bragg reflections have been measured for KRS-5 (TlBr/sub 0.46/I/sub 0.54/) at room temperature. From the observed intensities the mean Debye-Waller factor and the X-ray Debye temperature have been evaluated. The values of the Debye-Waller factor, mean square amplitude of vibration and the Debye temperature are 2.73 +- 0.06 A2, 0.104 +- 0.002 A2 and 90 +- 1 K, respectively. (author)
[en] Sodium bismuth titanate (Na1/2Bi1/2)TiO3 is strongly ferroelectric below 200 deg. C and antiferroelectric between 200 and 320 deg. C. The electrical conductivity of this ceramic is studied by measuring impedance as a function of temperature (RT-575 deg. C) and frequency (100 Hz-1 MHz). The complex impedance, electric modulus formalism and dielectric loss analysis are used to analyze the data. DC conductivity has been studied. The activation energies have been evaluated from the data. The dielectric constant of the sample has been calculated from the impedance data
[en] The aim of this study is to establish the sensitivity and specificity of MRA in the investigation of patients with traumatic anterior shoulder dislocations. A retrospective analysis of consecutive patients undergoing both magnetic resonance arthrography and arthroscopic assessment after a traumatic anterior shoulder dislocation between January 2011 and 2014 was performed. Demographic data were collected from electronic records. Images were interpreted by 8 musculoskeletal radiologists and patients were treated by 8 consultant orthopaedic surgeons. Arthroscopic findings were obtained from surgical notes and these findings were used as a reference for MRA. The sensitivity, specificity, and positive predictive value were calculated for the different injuries. Sixty-nine patients underwent both an MRA and shoulder arthroscopy during the study period; however, clinical notes were unavailable in 9 patients. Fifty-three patients (88 %) were male, the mean age was 28 years (range 18 to 50) and 16 subjects (27 %) had suffered a primary dislocation. The overall sensitivity and specificity of MRA to all associated injuries was 0.9 (CI 0.83-0.95) and 0.94 (CI 0.9-0.96) retrospectively. The lowest sensitivity was seen in osseous Bankart 0.8 (CI 0.44-0.96) and superior labral tear (SLAP) lesions 0.5 (CI 0.14-0.86). The overall positive predictive value was 0.88 (CI 0.76-0.91) with the lowest values found in rotator cuff 0.4 (CI 0.07-0.83) and glenohumeral ligament (GHL) lesions 0.29 (CI 0.05-0.7). Magnetic resonance angiography has a high sensitivity when used to identify associated injuries in shoulder dislocation, although in 8 patients (13 %) arthroscopy identified an additional injury. The overall agreement between MRA and arthroscopic findings was good, but the identification of GHL and rotator cuff injuries was poor. (orig.)
[en] Kinetics of oxidation of V(IV) by iron(III)-2,2'-bipyridyl complex have been studied spectrophotometrically in perchloric acid medium in the temperature range 10-25deg. The reaction is first order each with respect to [V(IV)] and [iron (III)]. The plots of 1/ksub(obs) versus 1/[bipyridyl] are linear with positive intercepts on 1/ksub(obs)-axis, suggesting that the 1:2 complex of iron (III) and bipyridyl acts as an active oxidizing species. An increase in [H+] decreases the rate of oxidation. The equilibrium constant of the complex and thermodynamic parameters of the complexation reaction have been evaluated. (author)
[en] Indian agriculture has achieved remarkable success in the food grain production due to inception of 'rainbow revolution', which made the country self-sufficient in food production. Sustainable agriculture (SA) is an ongoing process, in which people take actions leading to development of agriculture that meets their current needs without compromising the ability of future generations to meet their needs. It advocates avoiding all those actions, which reduce the ability of future generations to meet out the present generations. It is based on the optimal interaction between clean environment, healthy economy, and vital society by avoiding trade-off of problems to other regions on to the future. Moreover, sustainable agriculture is the function of people's progress and nature's capacity. In fact, SA commits us to considering the long-term effect and to recognize our place within the ecosystem. It encourages a continuous reflection on the implications of human activity on the ecosystem. Empirical evidences shows that in the race of self-sufficiency in food grain production, we compromised a lot on social and environmental fronts. The aftermath of green revolution is not so sustainable as it showed reverse side too, in the form of environmental degradation and ecological imbalances. Such threats have led to the need for promoting sustainable development in agriculture. Due to several unsustainable activities which resulted in resource degradation in the form of top soil loss, ground water depletion and forest degradation. The average soil loss is estimated to be over 16 tonnes/ha/year. The ground water depletion resulted in several blocks as 'grey blocks' and 'dark blocks'. This happened mainly due to increase in number of tube-wells and free supply of electricity making the cost of pumping water very low. Rate of human induced land degradation is very high. Out of total geographical area of 329.0 million ha, 187 million ha (57.0 %) are reported to have degraded, of which 162 million ha is wind and water related degradation. Moving from the existing unsustainable towards sustainable agriculture has in own social cost and benefits. The social costs, a society has to bear the short run may involve from loss of agriculture production to direct effect on employment opportunities in agriculture as well as allied sectors. But the social benefits of moving towards sustainable agriculture at least in the long run outweigh the initial social cost. For example - shifting from existing agriculture to SA benefits the society in terms of good soil, clean water, air improved productivity, which in turn will lead to the improved health of the society. Along with this, SA in the form of organic farming, vermiculture, etc. helps in providing additional employment and income to the society without any social cost (pollution (soil, air, water), and health, etc.). This paper analyzes the different dimensions of sustainable agriculture and its cost and benefits to the Indian society. Therefore, there is dire need to introduce policy measures. Viz., greater awareness about sustainability, proper education to farming community, and efficient management of natural resources to cater the serious challenge of sustainable agriculture. (author)
[en] Detailed kinetic study of the oxidation of tellurium (IV) by periodate in alkaline medium has been carried out to compare the mechanisms of oxidation in the acid and alkaline media. It is interesting to note that the rate step involves a two-electron transfer from tellurium (IV) to periodate in alkaline medium although the kinetic pattern is somewhat different from that in the acid medium. 7 refs., 1 tab
[en] This paper discusses the nature of radioactive occurrence in Chitrial Main Block in terms of distribution of uranium and radium with special emphasis on uranium and its disequilibrium behaviour based on the large number of higher order radioactive borehole core samples. The sample data is from eastern and western parts of the main block of Chitrial, which are close to the unconformity depth. The analytical results show that the radioelemental data of Chitrial area essentially belong to the same population and that there is a continuous influx of uranium into the system with strong disequilibrium in favour of parent uranium. (author)
[en] Organic-inorganic halide perovskites (OIHPs) are a remarkable family of hybrid materials at the heart of the emerging thin-film perovskite solar cells (PSCs) technology and other applications. In this Viewpoint article, in addition to some original experimental results, thermo-mechanical analyses of residual macro- and micro-stresses in OIHP thin films are presented in the context of fracture of both the OIHP layer itself and its interface with the substrate. The implications of mechanical behavior of OIHPs and interfaces on the reliability of PSCs, as well as opportunities for future research directions in this general area, are highlighted.
[en] A new aspect of electron recombination into highly charged ions (HCI) involving the coupling of the atomic shell to the nucleus in the process of nuclear excitation by electron transition (NEET) is investigated. In NEET, a bound electronic decay transition occurs with the simultaneous excitation of the nucleus, provided that the energies of the atomic and nuclear transition match. Our scenario involves the resonant process of dielectronic capture (DC) into HCI to create the electronic hole needed for NEET. HCI present the advantage that the atomic level energies are very sensitive to the ion charge state and offer the possibility to optimize the match between atomic and nuclear transition energies. The NEET probability can thus be enhanced by several orders of magnitude compared to neutral atoms. The total and interference cross section terms for the processes of radiative and dielectronic recombination, DC followed by NEET and γ decay and nuclear excitation by electron capture (NEEC) followed by γ decay were deduced and their magnitude investigated for the case of 237Np. Our results show that NEEC may be the most important contribution to the total recombination cross sections in HCI and that the interference terms, although small, are still larger than the NEET cross section.