Quantitative Approximation of Geothermal Potential of Bakreswar Geothermal Area in Eastern India

Proper utilization of geothermal energy for power generation is still overlooked in India even after having enough potential as much as the equivalent to its other nonconventional energy resources. The source of geothermal energy is the decay of the radio-nuclei present inside the Earth’s crust apart from the primordial heat source. The noble gas 4He is also produced during the radioactive disintegration process. Therefore, measuring the amount of 4He gas along with some other geochemical parameters in an Indian geothermal area, the potential of the reservoir can be evaluated. Mathematical calculations relating to the radioactive disintegration to estimate the geothermal potential of Bakreswar geothermal reservoir utilizing the concept of the 4He exploration technique has been described here. The study showed that the heat (radiogenic) energy generated by the radioactive decay of 232Th, 238U, and 235U inside the reservoir was evaluated as 38 MW. This value raises to 76 MW when primordial heat is included. The detail calculations suggest that a Kalina cycle based binary power plant using ammonia–water mixture as working fluid is supposed to be installed at the identified locations with a drilling depth of about 1,100 m and the plant would be capable of delivering the power of 9.88 MW to 40.26 MW

Metabolic Profiling of S-praziquantel: Structure Elucidation Using the Crystalline Sponge Method in Combination with Mass Spectrometry and Nuclear Magnetic Resonance

Praziquantel (PZQ) is the drug of choice for treatment of the neglected tropical disease schistosomiasis. Although the drug has been extensively used over several decades and its metabolism well studied (several oxidative metabolites are known from literature), the knowledge of the complete structure of some of its metabolites remains elusive. Conventional techniques, such as nuclear magnetic resonance or liquid chromatography mass spectrometry were used in the past to investigate phase I and phase II metabolites of PZQ. These techniques are either limited to provide the complete molecular structure (liquid chromatography mass spectrometry) or require large amount of sample material (NMR), which are not always available when in vitro systems are used for investigation of the metabolites. In this study, we describe new structures of S-PZQ metabolites generated in vitro from human liver microsomes using the crystalline sponge method. After chromatographic separation and purification of the oxidative metabolites, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis was conducted to narrow down the position of oxidation to a certain part of the molecule. To determine the exact position of hydroxylation, singe-crystal X-ray diffraction analysis of the crystalline sponges and absorbed analyte was used to identify the structure of S-PZQ and its metabolites. The crystalline sponge method allowed for complete structure elucidation of the known metabolites S-trans-4'-hydroxy-PZQ (M1), S-cis-4'-hydroxy-PZQ (M2) and S-/R-11b-hydroxy-PZQ (M6) as well as the unknown metabolites S-9-hydroxy-PZQ (M3) and S-7-hydroxy-S-PZQ (M4). For comparison of structural elucidation techniques, one metabolite (M3) was additionally analyzed using NMR. SIGNIFICANCE STATEMENT: The information content of the metabolic pathway of praziquantel is still limited. The crystalline sponge method allowed the complete structural elucidation of three known and two unknown metabolites of S-praziquantel, using only trace amounts of analyte material, as demonstrated in this study

Hygrothermal simulation-informed design of mesoporous desiccants for optimised energy efficiency of mixed mode air conditioning systems

This paper describes an optimization technique using hygrothermal numerical modelling to determine an ideal and unknown isotherm in order to inform the design of optimised mesoporous desiccants. Their suitability for passive humidity buffering as well as their impact on energy efficiency was assessed when assisting a mixed mode air-conditioning (AC) system. Three clear stages of water vapour adsorption were found that strongly correspond to the Dw gradient when assessing the kinetics of adsorption and exchange rates for periodic moisture loads. Consistent agreement was found between the latent heat of dehumidification used by the AC system and the desiccant decay time after successive sorption loop cycles. This confirmed the material's suitability for specific applications and was found to be highly sensitive to the portion of the isotherm between φi,L - φi,U (Dw gradient), compared with full adsorption capacity (total w) when assessing total energy consumption. The experimental results of sorption kinetics appeared to be slightly underestimated between the Dw gradient and the response time to reach equilibrium moisture content (EMC). The major underestimations were found to be consistent with the kinetics of adsorption/desorption when analysing their significance based on w differences. These were largely attributed to a combination of adsorption kinetics (time-response) and adsorption/desorption hysteresis. However, this was not evident when comparing long-term experimental data and numerical estimations for water vapour sorption isotherms, since numerical model accurately predicted them. This suggests that both adsorption kinetics and the scanning curve prediction, within a hysteresis loop, are not accurately represented by current hygrothermal models and are hence a priority for future research

“Directed” Assembly of Metallacalix[n]arenes with Pyrimidine Nucleobase Ligands of Low Symmetry: Metallacalix[n]arene Derivatives of cis-[a2M(cytosine-N3)2]2+ (M=PtII, PdII; n=4 and 6)

Pyrimidine (pym) ligands with their two endocyclic N-donor atoms provide 120° angles for molecular constructs, which, with the 90° angle metal fragments cis-a2MII (M=Pt, Pd; a=NH3 or a 2=diamine), form cyclic complexes known as metallacalix[n]arenes (with n=3, 4, 6, 8, ...). The number of possible isomers of these species depends on the symmetry of the pym ligand. Although highly symmetrical (C 2v) pym ligands form a single linkage isomer for any n and can adopt different conformations (e.g., cone, partial cone, 1,3-alternate, and 1,2-alternate in the case of n=4), low-symmetry pym ligands (Cs) can produce a higher number of linkage isomers (e.g., four in the case of n=4) and a large number of different conformers. In the absence of any self-sorting bias, the number of possible species derived from a self-assembly process between cis-a2MII and a Cs-symmetrical pym ligand can thus be very high. By using the Cs-symmetric pym nucleobase cytosine, we have demonstrated that the number of feasible isomers for n=4 can be reduced to one by applying preformed building blocks such as cis-[a 2M(cytosine-N3)2]n+ or cis-[a 2M(cytosinate-N1)2] (for the latter, see the accompanying paper: A. Khutia, P. J. Sanz Miguel, B. Lippert, Chem. Eur. J. 2011, 17, DOI: 10.1002/chem.2010002723) and treating them with additional cis-a 2MII. Moreover, intramolecular hydrogen-bonding interactions between the O2 and N4H2 sites of the cytosine ligands reduce the number of possible rotamers to one. This approach of the >directed> assembly of a defined metallacalix[4]arene is demonstrated.This work was supported by the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and the International Max Planck Research School in Chemical Biology in Dortmund (fellowship for A.K.).Peer Reviewe

Molecular Architectures Derived from Metal Ions and the Flexible 3,3′-Bipyridine Ligand: Unexpected Dimer with Hg(II)

The flexible ditopic ligand 3,3-bipyridine (3,3-bpy) has been reacted with a series of transition metal species (Ag+, Hg2+, cis-a2M2+ (a=NH3 or a2=en; M=Pt,Pd), trans-a2Pt2+ (a=NH3)) in an attempt to produce discrete cyclic constructs. While Ag+ gave a polymeric structure {[Ag(3,3-bpy)](ClO4) ⋅ H2O} (1), with all other metal entities cyclic structures were formed. Interestingly, Hg(CH3COO)2 produced a dinuclear complex [Hg(3,3-bpy)(CH3COO)2]2 ⋅ 3H2O (2), in which the two 3,3-bpy ligands adopt a cis-orientation of the coordinating pyridyl entities. With cis-(NH3)2Pt2+, a cyclic complex 4 was isolated in crystalline form which, according to HRMS, is a trimer. With trans-(NH3)2Pt2+, different species are formed according to 1H NMR spectroscopy, the nature of which was not established

Development of new cyclic plasticity model for 304LN stainless steel through simulation and experimental investigation

Cyclic plastic deformation characteristics of 304LN stainless steel material have been studied with two proposed cyclic plasticity models. Model MM-I has been proposed to improve the simulation of ratcheting phenomenon and model MM-II has the capability to simulate both cyclic hardening and softening characteristics of the material at various strain ranges. In the present paper, strain controlled simulations are performed with constant, increasing and decreasing strain amplitudes to verify the influences of loading schemes on cyclic plasticity behaviors through simulations and experiments. It is observed that the material 304LN exhibits non Masing characteristics under cyclic plastic deformation. The measured deviation from Masing is well established from the simulation as well as from experiment. Simulation result shows that the assumption of only isotropic hardening is unable to explain the hardening or softening characteristics of the material in low cycle fatigue test. The introduction of memory stress based cyclic hardening coefficient and an exponentially varying ratcheting parameter in the recall term of kinematic hardening rule, have resulted in exceptional improvement in the ratcheting simulation with the proposed model, MM-II. Plastic energy, shape and size of the hysteresis loops are additionally used to verify the nature of cyclic plasticity deformations. Ratcheting test and simulation have been performed to estimate the accumulated plastic strain with different mean and amplitude stresses. In the proposed model MM-I, a new proposition is incorporated for yield stress variation based on the memory stress of loading history along with the evolution of ratcheting parameter with an exponential function of plastic strain. These formulations lead to better realization of ratcheting rate in the transient cycles for all loading schemes. Effect of mean stress on the plastic energy is examined by the simulation model, MM-I. Finally, the micro structural investigation from transmission electronic microscopy is used to correlate the macroscopic and microscopic non Masing behavior of the material. (C) 2014 Elsevier Ltd. All rights reserved

“Directed” Assembly of Metallacalix[n]arenes with Pyrimidine Nucleobase Ligands of Low Symmetry: Interchanging Metals in Mixed-Metal Metallacalix[4]arenes and Incorporating Additional Metals at the Exocyclic Groups

The pyrimidine (pym) nucleobase cytosine (H2C) forms cyclic ring structures (>metallacalix[n]arenes>) when treated with square-planar cis-a2MII entities (M=Pt, Pd; a=NH3 or a 2=diamine). The number of possible linkage isomers for a given n and the number of possible rotamers can be substantially reduced if a >directed> approach is pursued. Hence, two cytosine ligands are bonded in a defined way to a kinetically robust platinum corner stone. In the accompanying paper (Part I: A. Khutia, P. J. Sanz Miguel, B. Lippert, Chem. Eur. J. 2010, 17, DOI: 10.1002/chem.2010002722) we have demonstrated this principle by allowing cis-[Pta2(H2C-N3)2]2+ to react with (en)PdII to give cycles of (N1,N3·N3,N1) x (with x=2 or 3; · represents PtII and a represents PdII). In an extension of this work we have now prepared cis-[Pta2(HC-N1)2] (1; HC=monoanion of cytosine) and treated it with (bpy)PdII (bpy=2,2′-bipyridine) to give the Pt2Pd2 cycle cis-[{Pt(NH3)2(N1-HC- N3)2Pd(bpy)}2](NO3)4·13H 2O (5) with the coordination sites of the metals inverted; hence, platinum is bonded to N1 and palladium is bonded to N3 sites. Again, not only the expected single linkage isomer is formed, but at the same time the solid-state structure and 1H NMR spectroscopy reveal the preferential occurrence of a single rotamer (1,3-alternate). The addition of (bpy)Pd II to 5 led to the formation of Pd6Pt2 complex 6 in which the exocyclic N4H2 groups of the cytosine ligands have undergone deprotonation and chelate four more (bpy)PdII entities through the O2 and N4H sites. With a large excess of (bpy)PdII over 5 (4:1), cis-(NH3)2PtII is eventually substituted by (bpy)PdII to give the Pd8 complex 7. In both 6 and 7 stacks of three (bpy)PdII entities occur. The linkage isomer of 5, cis-[{Pt(NH3)2(N3-HC-N1)2Pd(bpy)} 2](NO3)4·9H2O (8), has been structurally characterized and the two complexes compared. The acid/base properties of cis-[Pt(NH3)2(H2C-N1) 2] (1) have been determined and compared with those of the corresponding N3 isomer. The complexation of AgCl by 1 is reported.This work was supported by the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and the International Max Planck Research School in Chemical Biology in Dortmund (fellowship for A.K.).Peer Reviewe