On pressure dependence of the relative compression (V/V0) at room temperature for the solids : copper and lead as prototypes

A correction term has been introduced in the usual Tait’s equation of state (EOS) and then used to predict the pressure dependence of the thermal compression for the solids : copper (Cu) and lead (Pb). The predictive capabilities of the complete EOS are discussed. The results obtained from the modified Usual Tait’s equation of state are found closer to the available experimental data as compared to those values achieved without taking into account the correction factor in the original Tait’s equation of state.Author Affiliation: Deepika Kandpal, K Y Singh and B R K Gupta 1.Department of Physics, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, India E-mail : [email protected] of Physics, G. B. Pant University of Agriculture and Technology, Pantnagar-263145, Indi

Profitability of Integrated Farming System model for small and medium farmers of South Tripura, Tripura

The present study was carried out under Krishi Vigyan Kendra, South Tripura to study the production, profitability and employment generation of IFS over prevailing conventional rice-rice system of farming in South Tripura district of Tripura during 2015-16, 2016-17 and 2017-18. The components rice, maize, vegetables, ginger, apiculture, fishery, poultry and piggery were considered for the study under integrated farming system. The Integrated Farming System (IFS) model showed 17.79 % increase in productivity and 48.91 % higher net return over conventional rice-rice system.  Among the components evaluated, the highest per cent net return was received from Fishery unit (31.78), followed by Piggery unit (18.19), Apiculture (13.93), Poultry unit (12.96), Spice Ginger (10.19), Crop (7.31) and Vegetables (5.64) respectively. The highest B:C ratio (3.67) was obtained from fishery unit among all the component evaluated under the IFS. A total of 289 Man days/ha/year employments can be generated under Integrated Farming System. This system of IFS model may be useful in the areas where water is limiting and an efficient alternate system of conventional rice-rice system

Properties of the quaternary half-metal-type Heusler alloy Co2_2Mn1−x_{1-x}Fex_xSi

This work reports on the bulk properties of the quaternary Heusler alloy Co$_2$Mn$_{1-x}$Fe$_x$Si with the Fe concentration $x=$. All samples, which were prepared by arc melting, exhibit $L2_1$ long range order over the complete range of Fe concentration. Structural and magnetic properties of Co$_2$Mn$_{1-x}$Fe$_x$Si Heusler alloys were investigated by means of X-ray diffraction, high and low temperature magnetometry, M{\"o\ss}bauer spectroscopy, and differential scanning calorimetry. The electronic structure was explored by means of high energy photo emission spectroscopy at about 8 keV photon energy. This ensures true bulk sensitivity of the measurements. The magnetization of the Fe doped Heusler alloys is in agreement with the values of the magnetic moments expected for a Slater-Pauling like behavior of half-metallic ferromagnets. The experimental findings are discussed on the hand of self-consistent calculations of the electronic and magnetic structure. To achieve good agreement with experiment, the calculations indicate that on-site electron-electron correlation must be taken into account, even at low Fe concentration. The present investigation focuses on searching for the quaternary compound where the half-metallic behavior is stable against outside influences. Overall, the results suggest that the best candidate may be found at an iron concentration of about 50%.Comment: 26 pages, 9 figures Phys. Rev. B accepte

Covalent bonding and the nature of band gaps in some half-Heusler compounds

Half-Heusler compounds \textit{XYZ}, also called semi-Heusler compounds, crystallize in the MgAgAs structure, in the space group $F\bar43m$. We report a systematic examination of band gaps and the nature (covalent or ionic) of bonding in semiconducting 8- and 18- electron half-Heusler compounds through first-principles density functional calculations. We find the most appropriate description of these compounds from the viewpoint of electronic structures is one of a \textit{YZ} zinc blende lattice stuffed by the \textit{X} ion. Simple valence rules are obeyed for bonding in the 8-electron compound. For example, LiMgN can be written Li$^+$ + (MgN)$^-$, and (MgN)$^-$, which is isoelectronic with (SiSi), forms a zinc blende lattice. The 18-electron compounds can similarly be considered as obeying valence rules. A semiconductor such as TiCoSb can be written Ti$^{4+}$ + (CoSb)$^{4-}$; the latter unit is isoelectronic and isostructural with zinc-blende GaSb. For both the 8- and 18-electron compounds, when \textit{X} is fixed as some electropositive cation, the computed band gap varies approximately as the difference in Pauling electronegativities of \textit{Y} and \textit{Z}. What is particularly exciting is that this simple idea of a covalently bonded \textit{YZ} lattice can also be extended to the very important \textit{magnetic} half-Heusler phases; we describe these as valence compounds \textit{ie.} possessing a band gap at the Fermi energy albeit only in one spin direction. The \textit{local} moment in these magnetic compounds resides on the \textit{X} site.Comment: 18 pages and 14 figures (many in color

Brillouin light scattering study of Co2_{2}Cr0.6_{0.6}Fe0.4_{0.4}Al and Co2_{2}FeAl Heusler compounds

The thermal magnonic spectra of Co$_{2}$Cr$_{0.6}$Fe$_{0.4}$Al (CCFA) and Co$_2$FeAl were investigated using Brillouin light scattering spectroscopy (BLS). For CCFA, the exchange constant A (exchange stiffness D) is found to be 0.48 $\mu$erg/cm (203 meV A$^2$), while for Co$_2$FeAl the corresponding values of 1.55 $\mu$erg/cm (370 meV A$^2$) were found. The observed asymmetry in the BLS spectra between the Stokes and anti-Stokes frequencies was assigned to an interplay between the asymmetrical profiles of hybridized Damon-Esbach and perpendicular standing spin-wave modes, combined with the optical sensitivity of the BLS signal to the upper side of the CCFA or Co$_2$FeAl film

Legumes in the Indo-Gangetic Plain of India

Cropping in the Indo-Gangetic Plain of India covering 44 million ha is predominantly cereal based. Rice-wheat and rice-based cropping systems are the most important systems, with rice-wheat rotations covering about 10 million ha. Legumes account for about 5 million ha, which amounts to about 14% of the total area in the country. This region has large spatial variation in rainfall pattern (268 mm in the extreme north to 1600 mm in the extreme east), and is largely dominated by Inceptisol soils. There is large variation in other agroclimatic characteristics such as temperature regime, length of growing season, and evapotranspiration. Despite this large variation chickpea, lentil, and pigeonpea are cultivated as major legumes across the region. Their production in this diverse part of the country is severely constrained by a number of diseases, insect pests, and abiotic stresses. Socioeconomic constraints are also important in discouraging their production. The Government of India increased research outlay to develop improved technologies for increasing legumes production in the country. The results of Government investment were promising, and a number of improved cultivars and technology options were developed to alleviate biotic and abiotic constraints. The Government also initiated several policy measures to alleviate socioeconomic constraints for increasing legumes production. The available trends show that in some parts, legumes area is gradually increasing. The region shows huge potential for legumes production (either as a catch crop, summer crop, or sole crop in different cropping systems), provided appropriate cultivars/ technologies reach farmers' fields

A causal relationship between right paraduodenal hernia and superior mesenteric artery syndrome: a case report

<p>Abstract</p> <p>Introduction</p> <p>Cases of right paraduodenal hernia and superior mesenteric artery syndrome have been reported separately, but their occurrence in combination has not been reported.</p> <p>Case presentation</p> <p>A 46-year-old Japanese man who had never undergone laparotomy was admitted to our hospital due to an acute abdomen. An enhanced multidetector-row computed tomography scan of our patient showed a cluster of small intestines with ischemic change in his right lateral abdominal cavity. Emergency surgery was subsequently performed, and strangulation of the distal jejunum along with incidental right paraduodenal hernia was found. His necrotic ileum was resected, and the jejunum encapsulated by the sac was repaired manually without reduction.</p> <p>Three days after the operation, however, our patient developed vomiting. An upper gastrointestinal series revealed a straight line cut-off sign on the third portion of his duodenum. A second enhanced multidetector-row computed tomography scan showed that he had a lower aortomesenteric angle and a shorter aortomesenteric distance compared to his condition before his right paraduodenal hernia was surgically repaired. We strongly suspected that the right paraduodenal hernia repair may have induced superior mesenteric artery syndrome. On the 21st post-operative day, duodenojejunostomy was performed because conservative management had failed.</p> <p>Conclusions</p> <p>In this case, enhanced multidetector-row computed tomography, which permits reconstructed multiplanar imaging, helped us to visually identify these diseases easily. It is important to recognize that surgical repair of a right paraduodenal hernia may cause superior mesenteric artery syndrome.</p

First principles electronic structure of spinel LiCr2O4: A possible half-metal?

We have employed first-principles electronic structure calculations to examine the hypothetical (but plausible) oxide spinel, LiCr2O4 with the d^{2.5} electronic configuration. The cell (cubic) and internal (oxygen position) structural parameters have been obtained for this compound through structural relaxation in the first-principles framework. Within the one-electron band picture, we find that LiCr2O4 is magnetic, and a candidate half-metal. The electronic structure is substantially different from the closely related and well known rutile half-metal CrO2. In particular, we find a smaller conduction band width in the spinel compound, perhaps as a result of the distinct topology of the spinel crystal structure, and the reduced oxidation state. The magnetism and half-metallicity of LiCr2O4 has been mapped in the parameter space of its cubic crystal structure. Comparisons with superconducting LiTi2O4 (d^{0.5}), heavy-fermion LiV2O4 (d^{1.5}) and charge-ordering LiMn2O4 (d^{3.5}) suggest the effectiveness of a nearly-rigid band picture involving simple shifts of the position of E_F in these very different materials. Comparisons are also made with the electronic structure of ZnV2O4 (d^{2}), a correlated insulator that undergoes a structural and antiferromagnetic phase transition.Comment: 9 pages, 7 Figures, version as published in PR