Search

Summary: An ever‐increasing demand for energy due to increasing usage is driving the scientists to find out materials for their technological applications. In this regard, thermoelectric materials are considered to be excellent candidates as energy sources. Further, for the suitability of materials in device fabrication, the study of various thermophysical parameters is always required. We have therefore tried to explore various performances of SrCeO3 perovskite, systematically using density functional theory with different potentials. The electronic band structure profile of SrCeO3 shows semiconducting behaviour in the ground state. Thermoelectric performance indicators like Seebeck coefficient, thermal conductivity, electrical conductivity, and power factor have been estimated within temperature 0 to 700 K. Interestingly, SrCeO3 displays a figure of merit value 0.27 at 700 K. [ABSTRACT FROM AUTHOR]

Summary: The structural, electronic, magnetic, mechanical and thermodynamic properties of the Mn2PtCo Heusler alloy have been investigated in the frame work of density functional theory (DFT). The cohesive energies confirm the Cu2MnAl‐prototype structure of Mn2PtCo with the ferromagnetic phase. The spin polarized electronic band profile of the Mn2PtCo exhibits its metallic character by considering the generalized gradient approximation (GGA) and modified Becke‐Johnson (GGA‐mBJ) approximation in the calculations. The magnetic moment is calculated to ~9 μB and it is in accordance with the Slater‐Pauling rule. From the analysis of mechanical properties the brittle nature is anticipated. Further to seek the applications of Mn2PtCo in device fabrication, the thermodynamic properties like entropy, heat capacity at constant volume, Debye temperature, Gruneisen parameter and thermal expansion coefficient within the temperature and pressure range of 0 to 1000 K and 0 to 24 GPa, respectively have also been estimated. [ABSTRACT FROM AUTHOR]

• Half metallic behavior observed for PrFeO 3 and NdFeO 3 using modified Becke Johnson, applicable to spintronic devices. • Thermoelectric Efficiency is 0.38 for PrFeO 3. • NdFeO 3 and PrFeO 3 follows Anharmonic effect (Debye T3 law). • RFeO 3 block UV light and can be used as UV absorbers. We have investigated the rare-earth ferrites perovskite RFeO 3 (R = Pr, Nd) for their structural, electronic, magnetic, optical, thermodynamic, and thermoelectric behavior using DFT as incorporated in WIEN2K software package. We have used FPLAPW method with exchange–correlation potentials: GGA, mBJ, and mBJ + U for investigating the current problem. For electronic properties, we have studied the band profile, density of states, and electronic density of RFeO 3. The band profile of RFeO 3 comes out to be half-metallic in mBJ + U. Further, optical properties have been computed corresponding to photon energy (0–10 eV). Thermodynamic examination of these compounds is performed using the Quasi-Harmonic Debye model. Consequently, the thermodynamic parameters' variation has been examined with temperature (0–1200 K) as well as pressure (0–40 GPa). Finally, we have evaluated the thermoelectric parameters using BoltzTrap code, and their variation with temperature (50–1200 K) and chemical potential (−2 to 2 eV) has been presented. We have obtained a maximum thermoelectric efficiency of 0.38 for PrFeO 3 perovskite, and it is found that it increases with temperature. These materials are suitable to be used as a source in spintronic devices and UV absorbers. [ABSTRACT FROM AUTHOR]

• Quantum mechanical modeling using WIEN2K code. • Predicted various thermodynamic variables under high temperature and pressure. • Structure optimization of BeX (X=Ag, Au) intermetallics in Pm-3m structure. • Predicted elastic and mechanical properties. • Anharmonicity in the crystal reported. The present work reports thermodynamics of BeX(X = Ag, Au) intermetallics in terms of their unit cell volume, bulk moduli, molar heat capacity at constant volume, Gruneisen parameter, thermal expansion coefficient and Debye temperature using a computational quantum mechanical modeling in the frame work of Density-functional theory (DFT). The thermodynamic parameters were studied under temperature range of 0–1200 K and pressure range of 0–40 GPa. The molar heat capacity at constant volume for the considered intermetallics followed Debye T3 law and Dulong-Petit limit was achieved at certain temperature. Further, to understand the highest modes of vibrations in the materials, Debye temperatures for BeAg and BeAu were estimated as 430 K and 335 K, respectively at 0 K and 0 GPa. Furthermore, the thermal expansion coefficient described the dependence of expansion and contraction of the materials on changing temperature, depicting the strength of atomic bonding. Its high value indicated weak atomic bonding, which led to the low melting temperature in the solids. [ABSTRACT FROM AUTHOR]

Context: Several studies have reported that PD-L1 has shown therapeutic activity in various tumor types. However, its expression changes in a person on administration of NAC which is reported by very few studies. Aims: To find out the difference in the expression of PD-L1 by tumor cells after the administration of NAC. Settings and Design: This prospective study was conducted on 30 patients who were diagnosed with locally advanced breast carcinoma (LABC) between 2017 and 2019 and those who received NAC followed by surgery. Methods and Material: Breast cancer specimens were collected using core needle biopsy prior to administration of NAC and IHC was performed. Frequency and staining intensity of PD-L1 by tumor cells were analyzed. PD-L1 expression was dichotomized into two groups according to the frequency distributions of the H-scores. Statistical Analysis Used: The differences in expression of PD-L1 along with various parameters were analyzed using Chi-square test and Student's t test. Results: The mean age of the patients in our study was 51.37 ± 11.37 years. The response of NAC according to the RECIST criteria showed that most of patients (83.3%) showed complete response. Of the 30 cases, 11 (36.7%) patients were PD-L1 positive before the administration of NAC. We found a significant change in expression from positive to negative status, i.e., seven patients changed from positive to negative (p = 0.036). Upon comparing the PD-L1 expression before NAC, significant association was observed between the primary tumor (T) and tumor stage with high PD-L1 expression (p = 0.020 and P = 0.034). After NAC, 18 (69.2%) patients who were ER positive and 18 (69.2%) patients who were PR positive showed negative PD-L1 expression while none of them were positive in PD-L1 positive patients (p = 0.018 and P = 0.018). Conclusion: PD-L1 expression in a same person changes upon administration of NAC which may indirectly be used as a predictor of response to NAC. [ABSTRACT FROM AUTHOR]

The mechanical and thermodynamic results of some terbium chalcogenides, TbX (X = S, Se) compounds have been examined using full-potential linear augmented plane wave (FP-LAPW) method based on density functional theory. The local spin density approximation with Hubbard potential (LSDA+U) has been used for proper treatment of 4f-electrons of Tb. The magnetic moment of TbS and TbSe was calculated to be 5.44μB and 5.57μB, respectively. The ground state properties such as lattice parameter, bulk modulus, and pressure derivative of bulk modulus were obtained and found in good agreement with already available theory and experiment results. The mechanical properties such as Young modulus (E), shear modulus (G), Poisson ratio (υ), Cauchy pressure and B/G ratio were also predicted. Further, in thermodynamic properties, Debye temperatures (θD), specific heats at constant volume(CV), thermal expansion co-efficient (α), and entropies (S) and their behavior with high temperature(0–1200 K) and pressure (0–50 GPa) were also predicted. [ABSTRACT FROM AUTHOR]

• First theoretical prediction on electronic structure results of Sr 2 MnTaO 6. • Electronic structure presents half-metallic nature. • Elastic and mechanical properties have also been calculated. • Thermodynamic investigation has been carried within Debye model. • Thermoelectric properties has been calculated using Boltztrap code. Experimental lattice constant has been used for theoretical predictions on structural, elastic, mechanical, electronic magnetic thermoelectric and thermodynamic properties of Sr 2 MnTaO 6 double perovskite oxide within well-known ab-initio density functional theory. Optimized lattice constant has been employed for obtaining spin involved electronic structure results within generalized gradient approximation (GGA), Hubbard approximation (GGA + U) and modified Becke Johnson approximation (mBJ). Electronic results show half-metallic nature with majority spin channels as metallic and minority spin channels as semi-conducting. Magnetic moment calculated within GGA + U was found equal to 4 µ b. Calculated large value of Bulks modulus (B) and Young modulus (Y) characterize it as hard and stiffer material. Pugh ratio (B/G) and Cauchy pressure (C 12 –C 44) portray its brittle nature. Using Boltztrap code we have calculated the variation of electrical conductivity (σ/τ), Seebeck coefficient (S), electronic thermal conductivity (k/τ) and Power factor (PF) in both spin channels. (σ/τ) is found to have decreasing nature in spin up states and increasing nature in spin down states, hence confirms the metallic nature in spin up states and semi-conducting in spin down states. Seebeck coefficients (S) reveal the presence of positive charge carriers in spin up states and negative in spin down states. The computed value of total power factor was found to be 1.99 × 1012 WK−2 m−1 s−1 at 1000 K. Furthermore, we have computed pressure and temperature dependent thermodynamic parameters for this compound in the temperature range of 0 K to 1000 K and pressure range of 0 GPa to 18 GPa with a step size of 3 GPa. [ABSTRACT FROM AUTHOR]

Highlights • First theoretical prediction on electronic structure results of Ba 2 ZnOsO 6. • Electronic structure presents the half-metallic nature for the compound. • Magnetic study presents the ferromagnetic nature. • Thermodynamic properties have been calculated within quasi-harmonic Debye model. Abstract First successful ab initio calculations on electronic structure, magnetic, elasto-mechanical and thermodynamic properties of cubic double perovskite oxide Ba 2 ZnOsO 6 has been effectively calculated within density functional theory via full potential linearized augmented plane wave (FP-LAPW) method. The structural investigation exposes the ferromagnetic phase stability of the compound. The spin polarized electronic and magnetic properties were calculated within generalized gradient approximation (GGA), Hubbard approximation (GGA + U), mBJ (modified Becke-Johnson approximation). The electronic profile establishes half-metallic nature for the compound. The calculated total spin magnetic moment was found equal to 2 µ B. The elastic constants have been calculated and used to predict mechanical stuffs like Shear modulus (G) Poisson ratio (ν) and anisotropic factor (A). The calculated B/G and Cauchy pressure (C 12 -C 44) both characterize the material as brittle. The thermodynamic parameters like heat capacity and Debye temperature have also been predicted in the temperature range of 0 K–1000 K. [ABSTRACT FROM AUTHOR]

In this paper, we have performed a systematic investigation on structural, magnetic, electronic, mechanical, and thermodynamic properties of BaPuO3 perovskite within density functional theory (DFT) using generalized gradient approximations (GGA), onsite coulomb repulsion (GGA + U), and modified Becke-Johnson (mBJ). The calculated structural parameters were found in good agreement with the experimental results. A large value of magnetic moment equal to integer value of 4 μB was obtained for the compound. The spin-polarized electronic band structure and density of states present 100% of spin polarization at Fermi level, resulting in half-metallic nature for the compound with spin-up states as metallic and spin- down states as a semiconducting. The elastic and mechanical properties have also been predicted. Moreover, we have calculated thermodynamic properties like Debye temperature (휃D), specific heat (CV), entropy (S), etc. using quasi-harmonic Debye model. [ABSTRACT FROM AUTHOR]

The structural, electronic, magnetic, elastic, and thermodynamic properties of cubic AMO3 perovskites (A = Eu, M = Ga, In) have been successfully studied within density functional theory using full-potential linearized augmented plane wave (FP-LAPW). The structural study reveals that both the compounds are stable in ferromagnetic states. The GGA + U calculated spin-polarized electronic band and density of states present the half-metallic nature of both the compounds. The magnetic moments calculated with different approximations were found to be approximately 6 μB for EuGaO3 and approximately 7 μB for EuInO3. From elastic calculation, the three independent elastic constants (C11, C12, C44) have been acquired to yield the mechanical properties like Young modulus (Y ), shear modulus (G), Poisson ratio (ν), and anisotropic factor (A). The calculated values of B/G show that both the compounds are ductile in nature. The thermodynamic study was also accomplished by exploring the thermodynamic parameters like specific heat, heat capacity, thermal expansion, Grüneisen parameter, Debye temperature, etc. within the temperature range 0 to 900 K and pressure range 0 to 50 GPa. [ABSTRACT FROM AUTHOR]

The structural, electronic, mechanical and thermodynamic properties of the perovskite oxide BaAmO have been predicted using the full-potential linearized augmented plane wave (FP-LAPW) method. The equilibrium lattice constant, bulk modulus and pressure derivative were computed using different exchange correlations. The optimization of structure was carried out in ferromagnetic, anti-ferromagnetic and non-magnetic states, and the compound was found to be stable in the ferromagnetic state. A systematic study on the band structure and density of states was accomplished using generalized gradient approximation (GGA), Hubbard approximation (GGA + U) and modified Becke-Johnson exchange potential (mBJ),and the compound was found to have a half-metallic nature in all the approximations. The calculated total spin magnetic moment was found to be 5 μ in all the approximations used. The second-order elastic constants, Young modulus, shear modulus, Poisson ratio and anisotropic factor have also been calculated. In order to have a complete understanding of BaAmO, the thermodynamic properties were studied in the pressure range of 0 to 40 GPa and the temperature range extending from 0 to 600 K. [ABSTRACT FROM AUTHOR]

For the first time, the americium-based perovskite SrAmO has been studied with respect to its structural, electronic, magnetic, mechanical, and thermodynamic properties. The study has been carried within the well-known density functional theory (DFT) using different approximations such as local spin density approximation (LSDA), generalized gradient approximation (GGA), LSDA + U, GGA + U. In order to check for the stable ground state, optimization was performed for non-magnetic, ferromagnetic, and anti-ferromagnetic phases, and the compound was found to be stable in the ferromagnetic phase. The spin magnetic moment was obtained with different exchange correlations and was found to be an integer which is one of the consequences of half-metallic nature. The half-metallic nature of SrAmO was also confirmed from spin-polarised band structure calculations using GGA, GGA + U, and mBJ, showing metallic nature in spin-up states and semi-conducting in spin-down states. The elastic constants, Young modulus, shear modulus, Poisson ratio, and anisotropic factor were also calculated. SrAmO was found to establish ductile and anisotropic nature. Debye temperature was predicted to be 353 K from elastic constants. The thermodynamic properties, like variation of specific heat capacity, thermal expansion, and entropy, were studied in the temperature range of 0 to 600 K. [ABSTRACT FROM AUTHOR]

[Display omitted] • L2 1 structure is stable structure for Rh 2 XZn (X = Mn, Fe). • Rh 2 XZn (X = Mn, Fe) are ferromagnetic in nature with 3.12 & 4.6 µ B , magnetic moments. • Low values of thermal conductivity which is accountable for figure of merit. • Predicted ZT for energy based applications. • High values of Debye temperature for the considered materials. Rh 2 XZn (X = Mn, Zn), full-Heusler compounds have been investigated with respect to their transport and thermodynamic properties using the first-principles approach. The full potential linearized augmented plane wave method with different exchange potentials is used to find the structural stability within considered L2 1 and XA structures. Moreover, Rh 2 XZn (X = Fe, Zn) are found to be ferromagnetic with magnetic moments of ∼3 and ∼4µ B , which are compatible with the Pauling-Slater rule. To further seek the application of the material in the transport phenomena, figure of merit has been estimated by using Boltzmann theory. Our calculations lead to a 0.15 value of figure of merit at 1200 K for Rh 2 FeZn. Furthermore, the thermodynamic stability has been examined by considering various parameters within 0 to 1200 K temperature range. One of the novelties lies within the high value of Debye temperature that surmised the materials to be used as hard materials. [ABSTRACT FROM AUTHOR]

Eight in situ solidification/stabilization (ISS) amendments were tested to promote in situ chemical oxidation (ISCO) with activated persulfate (PS) in a contaminated soil. A 3% (by weight) dose of all ISS amendments selected for this study completely activated a 1.5% dose of PS within 3 h by raising temperatures above 30 °C (heat activation) and/or increasing pH above 10.5 (alkaline activation). Heat is released by the reaction of CaO with water, and pH increases because this reaction produces Ca(OH) 2 . Heat activation is preferred because it generates 2 mol of oxidizing radicals per mole of PS, whereas alkaline activation releases only 1. The relative contribution of heat vs. alkaline activation increased with CaO content of the ISS amendment, which was reflected by enhanced contaminant oxidation with increasing CaO content, and was confirmed by comparing to controls promoting purely heat or alkaline (NaOH) activation. The test soil was contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAH), particularly naphthalene (NAP). ISS-activated PS oxidized between 47% and 84% of the BTEX & NAP, and between 13% and 33% of the higher molecular weight PAH. ISS-activated PS reduced the leachability of BTEX & NAP by 76%–91% and of the 17 PAH by 83%–96%. Combined ISCO/ISS reduced contaminant leachability far than ISCO or ISS treatments alone, demonstrating the synergy that is possible with combined remedies. [ABSTRACT FROM AUTHOR]

Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene ( dsrA ) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks. [ABSTRACT FROM AUTHOR]

Abstract: The high pressure structural, elastic and thermal properties of holmium pnictides HoX (X=N, P, As and Bi) were investigated theoretically by using an inter-ionic potential theory with modified ionic charge parameter. We have predicted a structural phase transition from NaCl (B1) to CsCl (B2)-type structure at pressure of 139GPa for HoN, 52GPa for HoP, 44GPa for HoAs and 26GPa for HoBi. Other properties, such as lattice constant, bulk modulus, cohesive energy, second and third-order elastic constants were calculated and compared with the available experimental and theoretical data. In order to gain further information the brittle behaviour of these compounds was observed. Some other properties like Shear modulus (G), Young''s modulus (E), Poisson''s ratio (ν), anisotropy factor (A), sound velocities, Debye temperature (θ D ) were calculated. The variation of elastic constants (C 11 and C 44) and Debye temperature (θ D ) with pressure was also presented. [Copyright &y& Elsevier]

Abstract: Ab initio calculation on B2-cadmium rare earth (RE), CdRE (RE=La, Ce and Pr) intermetallics has been performed at T=0K with respect to their structural, electronic and thermal properties. The structural and electronic properties are derived using self-consistent tight binding linear muffin tin orbital method at ambient and at high pressure. Other properties like lattice parameter, bulk modulus, density of states, electronic specific heat coefficient, cohesive energy, heat of formation, Debye temperature and Grüneisen constant for CdRE are also estimated. The RE–f effect can be seen in CdPr in terms of variation in the density of states and opens a possibility of structural instability. A pressure induced variation of Debye temperature is also presented for three cadmium rare earth intermetallics. [Copyright &y& Elsevier]

Abstract: The structural and mechanical properties of LnO (Ln=Sm, Eu, Yb) compounds have been investigated using a modified interionic potential theory, which includes the effect of Coulomb screening. We predicted a structural phase transition from NaCl (B1)- to CsCl (B2)-type structure and elastic properties in LnO compounds at very high pressure. The anomalous properties of these compounds have been correlated in terms of the hybridisation of f-electrons of the rare earth ion with conduction band and strong mixing of f-states of lanthanides with the p-orbital of neighbouring chalcogen ion. For EuO, the calculated transition pressure, bulk modulus and lattice parameter are close to the experimental data. The nature of bonds between the ions is predicted by simulating the ion–ion (Ln–Ln and Ln–O) distances at high pressure. The second order elastic constants along with shear modulus and Young''s modulus, elastic anisotropy and Poisson''s ratio are also presented for these oxides. [Copyright &y& Elsevier]

The results of first principles calculations of the electronic band structures, density of states, band gap, equilibrium lattice constants, cohesive energies, bulk moduli and magnetic moments are presented for the EuN with rock salt as ambient structure and cesium chloride as high-pressure structure. The tight-binding linear muffin tin orbital method within the local-density approximation is used. Both spin-polarized and non-spin polarized calculations are performed. The magnetic and structural stabilities are determined from the total energy calculations for both nonmagnetic (NM) and ferro-magnetic (FM) states. From the present study EuN illustrates half-metallic. The FM phase is more stable than NM phase. We further predict EuN undergoes a transition from NaCl-type (B1) to CsCl-type structure (B2) at 14.6 GPa, which could not be compared owing to the need of experimental and theoretical results. Futhermore, the bulk moduli, first-order pressure derivatives and magnetic moments are also estimated in B1 and B2 phases. The magnetic moment is estimated to be nearly 6 μB, which is in good agreement with the others reported value. A small decrease in magnetic moment is observed under pressure. [ABSTRACT FROM AUTHOR]

Abstract: The ground state electronic structure and thermal properties of B2-type intermetallic compounds AlRE (RE: Pm, Sm, Eu, Tb, Gd and Dy) have been studied using a self-consistent tight-binding linear muffin-tin orbital (TB-LMTO) method at ambient as well as at high pressure. These compounds show metallic behavior under ambient condition. The band structure, total energy, density of states and ground state properties like lattice parameter, bulk modulus are calculated in the present work. The Debye–Grüneisen model is used to calculate the Debye temperature and the Grüneisen constant. The calculated results are in good agreement with the reported experimental and other theoretical results. The variation in the Debye temperature with pressure has also been reported. We present a detailed analysis of the role of f electrons of RE in the AlRE system. [ABSTRACT FROM AUTHOR]

nti-bacterial drug resistance is one of the most critical concerns among the scientist worldwide. The novel antimicrobial decapeptide SD-8 is designed and its minimal inhibitory concentration and therapeutic index (TI) was found in the range of 1-8 μg/ml and 45-360, respectively, against major group of Gram positive pathogens (GPP). The peptide was also found to be least hemolytic at a concentration of 180 μg/ml, i.e., nearly 77 times higher than its average effective concentration. The kinetics assay showed that the killing time is 120 min for methicillin-sensitive Staphylococcus aureus (MSSA) and 90 min for methicillin-resistant S. aureus (MRSA). Membrane permeabilization is the cause of peptide antimicrobial activity as shown by the transmission electron microscopy studies. The peptide showed the anti-inflammatory property by inhibiting COX-2 with a K and K values of 2.36 × 10 and 4.8 × 10 M, respectively. The peptide was also found to be effective in vivo as derived from histopathological observations in a Staphylococcal skin infection rat model with MRSA as causative organism. [ABSTRACT FROM AUTHOR]

Abstract: We present the results of theoretical calculations on the structural, magnetic and electronic properties of Er-monopnictides using self-consistent first principles tight-binding linear-muffin-tin-orbital (TB-LMTO) method within the atomic-sphere approximation (ASA). Both spin-polarized and non-spin-polarized calculations are performed to check the magnetic stability of these compounds. We find that ErN, ErP and ErAs are metallic in ferromagnetic (FM) phase in both the spin channels and stable in NaCl-type (B1) structure at ambient pressure. We predict NaCl-type (B1) to CsCl-type (B2) structural phase transition in ErN, ErP and ErAs at pressures of 146.1, 60.2 and 53.2GPa, respectively and remain metallic ferromagnetic at high pressure. We calculate equilibrium lattice constants (a), bulk modulus (B), magnetic moments (μB) and electronic properties of these compounds in B1 and B2 phases and compare with available experimental and theoretical results. [Copyright &y& Elsevier]

Abstract: We have investigated, the cohesive energies, equilibrium lattice constants, pressure–volume relationship, phase transition pressure (P T), elastic constants and variation of elastic constants with pressure for yttrium pnictides (YX; X=N, P, As and Sb), using an interionic potential theory with modified ionic charge which, includes Coulomb screening effect due to d-electrons. These compounds undergo structural phase transition from NaCl (B1) to CsCl (B2) structure at high pressure (ranges 20–130GPa). We have also calculated bulk (BT ), Young (E), and shear moduli (G), Poisson ratio (υ) and anisotropic ratio (A) in NaCl (B1)-type structure for yttrium pnictides and compared them with other experimental and theoretical results which show a good agreement. [Copyright &y& Elsevier]

Abstract: The tight-binding linear muffin tin orbital (TB-LMTO) method within the local density approximation is used to calculate structural, electronic and magnetic properties of GdN under pressure. Both nonmagnetic (NM) and magnetic calculations are performed. The structural and magnetic stabilities are determined from the total energy calculations. The magnetic to ferromagnetic (FM) transition is not calculated. Magnetically, GdN is stable in the FM state, while its ambient structure is found to be stable in the NaCl-type (B1) structure. We predict NaCl-type to CsCl-type structure phase transition in GdN at a pressure of 30.4GPa. In a complete spin of FM GdN the electronic band picture of one spin shows metallic, while the other spin shows its semiconducting behavior, resulting in half-metallic behavior at both ambient and high pressures. We have, therefore, calculated electronic band structures, equilibrium lattice constants, cohesive energies, bulk moduli and magnetic moments for GdN in the B1 and B2 phases. The magnetic moment, equilibrium lattice parameter and bulk modulus is calculated to be 6.99 μ B, 4.935Å and 192.13GPa, respectively, which are in good agreement with the experimental results. [Copyright &y& Elsevier]

Abstract: The electronic, structural and magnetic properties of half-metallic promethium nitride (PmN) have been studied using first-principles tight-binding linear muffin-tin orbital (TB-LMTO) method within the local-density approximation (LDA). We calculate the total energy, lattice parameter, bulk modulus, magnetic moment, density of states and energy band structures of half-metallic PmN at ambient as well as at high pressure. Both spin-polarised and non-spin-polarised electronic calculations are performed to check the magnetic stability of PmN. It is found that PmN is ferromagnetically stable. From the total energy calculations it is also found that PmN is stable in the NaCl-type structure under ambient conditions. The structural stability of PmN changes under the application of pressure. We predict a structural phase transformation from NaCl- to CsCl-type structure at the pressure of 3.4GPa. The high-pressure phase of PmN remains half-metallic and ferromagnetic. The calculated equilibrium lattice parameter and bulk modulus are in good agreement with the experimental and theoretical work. [Copyright &y& Elsevier]

Abstract: A study on structural and electronic properties of non-magnetic cubic B2-type AlRE (RE=Sc, Y, La, Ce, Pr and Lu) intermetallics has been done theoretically. The self-consistent tight binding linear muffin tin orbital method is used to describe the electronic properties of these intermetallics at ambient and at high pressure. These compounds show metallic behavior under ambient conditions. The variation of density of states under compression indicates some possibility of structural phase transformation in AlLa, AlCe and AlPr. Thermal properties like Debye temperature and Grüneisen constant are calculated at T=0K and at ambient pressure within the Debye–Grüneisen model and compared with the others’ theoretical results. Our results are in good agreement. We have also performed a pressure-induced variation of Debye temperature and have found a decrease in Debye temperature around 40kbar in AlRE (RE=La, Ce, Pr) intermetallics. [Copyright &y& Elsevier]

Abstract: Pressure induced structural phase transition of mono-antimonides of lanthanum, cerium, praseodymium and neodymium (LnSb, Ln=La, Ce, Pr and Nd) has been studied theoretically using an inter-ionic potential with modified ionic charge which parametrically includes the effect of Coulomb screening by the delocalized f electrons of rare earth (RE) ion. The anomalous structural properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of Ln ion with the p orbital of neighbouring antimonide ion. All the four compounds are found to undergo from their initial NaCl (B1) phase to body centered tetragonal (BCT) phase at high pressure and agree well with the experimental results. The body centered tetragonal phase is viewed as distorted CsCl structure and is highly anisotropic with c/a=0.82. The transition pressure of LnSb compounds is observed to increase with decreasing lattice constant in NaCl phase. The nature of bonds between the ions is predicted by simulating the ion-ion (Ln–Ln and Ln–Sb) distances at high pressure. The calculated values of elastic constants are also reported. [Copyright &y& Elsevier]

We have investigated the structural and elastic properties of three plutonium mono-chalcogenides (PuX; X=S, Se, Te) and three mono-pnictides (PuY; Y=As, Sb, Bi) using an interionic potential theory with modified ionic charge, at high pressure. This method has been found quite satisfactory in the case of cerium mono-chalcogenides and mono-pnictides. The calculated equation of state, phase transition pressure, and bulk modulus agree well with the experimental findings. We have also reported the second order elastic constants (SOEC) for these Pu compounds, for the first time. A comparison of the properties of chalcogenides and pnictides of shifted homolog pair Ce–Pu, is also presented. [Copyright &y& Elsevier]

Pressure-induced structural phase transitions at high-pressure in monosulfides of thorium, uranium, neptunium and plutonium (AnS) have been studied theoretically by an inter-ionic potential theory with modified ionic charge introduced to include the Coulomb screening effect due to localized 'f' electrons. These AnS compounds undergo a phase transition from sodium chloride (NaCl) to cesium chloride (CsCl) structure at a very high-pressure. The present theoretical investigation carried out up to 120 GPa reveals that these compounds undergo NaCl-CsCl phase transitions at 100, 81, 75 and 105 GPa for ThS, US, NpS and PuS, respectively. The first-order pressure derivatives calculated from the present theory agree well with observed data. [ABSTRACT FROM AUTHOR]

In this study CoZrMnSb, a quaternary Heusler alloy has been explored utilizing the density functional theory based simulation package WIEN2k. The structural analysis exhibits an X1-type structure with a relaxed lattice constant of 6.27 Å in ferromagnetic phase. The band structure calculations show its half-metallic nature with full spin polarization states around the Fermi level at 0.56 eV energy. In addition, the magnetic moment is calculated to be 1.0 μB, which is in accordance with the Slater Pauling rule (Mtot = (Ztot–24) μB). The study shows the d-d hybridization of the transition metals Co, Zr, and Mn elements. Further, optoelectronic performances in terms of dielectric function, reflectivity, energy loss function, absorption coefficient have been determined for a range of photon energy up to12 eV (ultraviolet region). In optoelectronic applications, absorption of this material in visible light enhances its significance. The thermoelectric properties with chemical potential and thermodynamic properties in the pressure range of 0–40 GPa and temperature range of 0–1200 K have been analysed. Specific heat capacity and Debye temperature authenticate similar metallic behaviour of CoZrMnSb alloy at temperature versus pressure variations. At room temperature, the chemical potential study suggests high figure of merit ~ 0.9, which makes it a potential thermoelectric material. The suggested material has a high Seebeck coefficient and low thermal conductivity, making it a better match for waste heat recovery and spintronic applications. [ABSTRACT FROM AUTHOR]

Modern manufacturing is primarily focused on providing things that are accessible, environmentally conscious, and energy efficient. An effort has been made herein to investigate the compounds that meet these requirements. The full‐potential linearized augmented plane wave method, in Wien2k code, is used to examine the structural, vibrational, mechanical, and transport properties of XVIn (X = Pd, Pt) half‐Heusler compounds. The generalized gradient approximation is used for structural optimization. The computed lattice constants are consistent with earlier theoretical and experimental results. The XVIn (X = Pd, Pt) investigation reveals that the material is inherently ductile and mechanically stable. It is found that XVIn (X = Pd, Pt) has a direct bandgap and a semiconducting property. The modified Becke–Johnson exchange approximation yields bandgap magnitudes of 0.25 and 0.55 eV for PdVIn and PtVIn, respectively. The Boltzmann transport offered by the BoltzTrap software is used to explore thermoelectric characteristics. The values of figure of merit (ZT) obtained for XVIn (X = Pd, Pt) compounds are very close to unity in the chemical potential range from −0.15 to 0.15 eV, indicating that they can be used to make thermoelectric devices with the maximum possible efficiency. [ABSTRACT FROM AUTHOR]

Reports on the pilot study conducted by the Institute of Gas Technology to test the effectiveness of a chemical/biological process to clean soils contaminated with polynuclear aromatic hydrocarbons. Quality of air emissions from slurry phase application; Destruction of contaminants within the soil phase; Minimal air pollution control and monitoring. INSET: Implications..

• DFT calculations on ferromagnetic Mn2CoCr with GGA and mBJ approximations. • Predicted specific heat at constant volume and approaches to Dulong-Petit limit. • Mn 2 CoCr is new material exhibits good thermoelectric properties. • Seebeck coefficient, thermal conductivity, power factor calculated for the first time. • Prediction on Debye temperature and thermal expansion coefficient. Heusler compounds have been promising materials for their applications in spintronic, memory and thermoelectric devices. The Mn 2 CoCr, a full Heusler compound, has been investigated here for its mechanical, thermodynamic and thermoelectric prospective for the first time using full potential linearized augmented plane wave (FP-LAPW) method in support of density functional theory (DFT). The estimation of total energy conferred to Fm-3m structure in ferromagnetic phase, which was in accordance to the others finding. The estimated total magnetic moment was found to be 5.02 (in the units of Bohr magneton), which was in accordance with the Pauling-Slater rule and available data. The electronic structure using generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) revealed its metallic nature in both the spin configurations. Further, we have calculated the thermodynamic and thermoelectric constants such as specific heat, Debye temperature, Gruneisen constant, thermal conductivity, Seebeck coefficient and power factor. Our predicted value of specific heat at constant volume is 66.6 J/mol.K at 300 K and 0 GPa, which at higher temperature (1000 K) followed Dulong-Petit limit. The power factor was calculated to be 25x1012 Wm-1K−2 at 500 K, demonstrating its suitability in thermoelectric applications. [ABSTRACT FROM AUTHOR]

• Using the first-principles method, the structural, optoelectronic, and transport properties of anti-perovskite Na 3 SCl compounds have been determined. • An essential direct energy bandgap (Eg) of 3.493 eV compounds is displayed in the band structure computed using the modified Becke–Johnson potential (mBJ). • The optical response was examined with respect to photon energy (eV) up to 12 eV in terms of dielectric constants, refractive index, extinction coefficient, and energy loss function. • The classical Boltzmann transport theory accounts for the transport properties such as the Seebeck coefficient, electrical and thermal conductivity, power factor versus temperature, carrier concentration, and chemical potential. In the present work, we give a thorough analysis of the cubic inverse-perovskite Na 3 SCl's structural, electrical, optical, and thermoelectric properties using the FP-LAPW approach within the context of DFT. PBE-GGA has espoused for exchange-correlation the potential for the evaluation of structural characteristics. A well-known accurate potential for the computation of electronic structures known as TB-mBJ has also been added along with PBE-GGA for the computations of band structures and their density of states. The probe of cohesive energy, formation energy, and elastic aspects demonstrates that the material under study is chemically, and thermodynamically stable. The obtained lattice parameters and other structural data of the investigated Na 3 SCl are in well agreement with the reported results of similar compounds. A direct band gap of 3.493 eV identified from the band structure for Na 3 SCl demonstrates the semiconducting character of the examined antiperovskite. Charge density contours analysis reveals that Na 3 SCl possesses an ionic nature, which is confirmed by electron localization function (ELF) analysis. We additionally assessed optical constants for the Na 3 SCl, such as the dielectric function, optical reflectivity, refractive index, and electron energy loss, with radiation up to 12 eV. Furthermore, variations in temperature-dependent thermoelectric features in terms of Seebeck coefficient, thermal conductivity, electrical conductivity, power factor, and figure of merit have been determined for the first time using the BoltzTraP code. The perovskite under study has a p-type semiconducting nature, as indicated by the estimated positive Seebeck value, and holes rather than electrons are the predominant charge carriers for conduction. The obtained substantial figure of merit along with the low thermal-to-electrical conductivity ratio for the examined inverse perovskite imply it is suitable for thermoelectric applications in devices. Our examined Na 3 SCl inverse perovskite offers a fruitful framework for enhancing comprehensive TE efficacy for TE usage and green energy generation. [ABSTRACT FROM AUTHOR]

In the search for new and novel materials for various thermo‐physical applications, we have reported the magnetic, electronic, mechanical, thermal, and thermoelectric transport properties of two full Heusler alloys (HAs), Ru2MnV and Ru2MnNb. In order to obtain a stable structure, volume optimization was carried out in the Fm‐3m (225) and F43‐m (216) space groups. The Fm‐3m space group was found to be a stable phase for both alloys. Electronic results show the metallic nature of these alloys. Ferromagnetic moments of 4.06 and 4.18 μB were obtained for Ru2MnV and Ru2MnNb, respectively. Mechanical results show a brittle nature for Ru2MnV and a ductile nature for Ru2MnNb with a high melting temperature for Ru2MnV. Thermoelectric properties such as figure of merit along with Seebeck coefficient, electrical conductivity, power factor, and thermal conductivity have also been calculated. Furthermore, the thermodynamic results of the studied materials have also been evaluated to understand the nature of various thermodynamic parameters with respect to temperature and pressure. [ABSTRACT FROM AUTHOR]

High pressure electronic, elastic, mechanical, and thermodynamic properties of cubic perovskite SnTaO3 have been explored with density function theory (DFT), and the quasi-harmonic Debye model has been applied for the incorporation of high temperature. The experimental lattice constant has been used for the optimization of structure. The optimization results present the paramagnetic (PM) nature of the compound. The spin dependent electronic band structures at ambient conditions and under high pressure present the metallic nature with complete uniformity for the majority and minority spin states. The mechanical properties, such as Young’s modulus and bulk modulus, have been calculated and suggest an increase in stiffness and hardness of the material under the application of pressure. The thermodynamic properties, such as specific heat and Grüneisen parameter, have been predicted in the temperature range of 0 to 1000 K and pressure range of 0 to 60 Gpa. [ABSTRACT FROM AUTHOR]

Herein, we report our density functional theory calculations for structure, electronic, thermodynamic and mechanical properties of MBiO3 (M = Rb, Cs, Tl), compounds of perovskites oxide family. Exchange-correlation potential was treated with generalized gradient and local density approximations. From available ionic data, the tolerance factors and lattice constants were calculated. The values of tolerance factors provided the stability guarantee of MBiO3 compounds in cubic phase while the obtained lattice constants are in accordance to the available data. The cubic phase stability was further confirmed from elastic constants. The electronic structure results disclosed these materials as metallic. Mechanically, all the three perovskites were found as brittle from Cauchy's pressure, Pugh ratio and Poisson's ratio. The thermodynamic calculations have been performed using quasi-harmonic Debye model. Thermal properties like Debye temperature, specific heat capacity and thermal expansion have been presented with the variation of temperature and pressure. [ABSTRACT FROM AUTHOR]