Investigation on the effect of oxalic acid,succinic acid and aspartic acid on the gas hydrate formation kinetics

Gas hydrate reserves are potential source of clean energy having low molecular weight hydrocarbons trapped in water cages. In this work, we report how organic compounds of different chain lengths and hydrophilicities when used in small concentration may modify hydrate growth and either act as hydrate inhibitors or promoters. Hydrate promoters foster the hydrate growth kinetics and are used in novel applications such as methane storage as solidified natural gas, desalination of sea water and gas separation. On the other hand, gas hydrate inhibitors are used in oil and gas pipelines to alter the rate at which gas hydrate nucleates and grows. Inhibitors such as methanol and ethanol which form strong hydrogen bond with water have been traditionally used as hydrate inhibitors. However, due to relatively high volatility a significant portion of these inhibitors ends up in gas stream and brings further complexity to the safe transportation of natural gas. In this study, organic additives such as oxalic acid, succinic acid and L-aspartic acid (all three) having—COOH group(s) with aspartic acid having an additional—NH₂ group, are investigated for gas hydrate promotion/inhibition behavior. These compounds are polar in nature and thus have significant solubility in liquid water; the presence of weak acidic and water loving (carboxylic/amine groups) moieties makes these organic acids an excellent candidate for further study. This study would pave ways to identify a novel(read better) promoter/inhibitor for gas hydrate formation. Suitable thermodynamic conditions were generated in a stirred tank reactor coupled with cooling system; comparison of gas hydrate formation kinetics with and without additives were carried out to identify the effect of these acids on the formation and growth of hydrates. The possible mechanisms by which these additives inhibit or promote the hydrate growth are also discussed.     

Chiral Graphs: Reduced Representations of Ligand Scaffolds for Stereoselective Biomolecular Recognition,Drug Design,and Enhanced Exploration of Chemical Structure Space

Rational structure-based drug design relies on a detailed, atomic-level understanding of protein–ligand interactions. The chiral nature of drug binding sites in proteins has led to the discovery of predominantly chiral drugs. A mechanistic understanding of stereoselectivity (which governs how one stereoisomer of a drug might bind stronger than the others to a protein) depends on the topology of stereocenters in the chiral molecule. Chiral graphs and reduced chiral graphs, introduced here, are new topological representations of chiral ligands using graph theory, to facilitate a detailed understanding of chiral recognition of ligands/drugs by proteins. These representations are demonstrated by application to all ≈14 000+ chiral ligands in the Protein Data Bank (PDB), which will facilitate an understanding of protein–ligand stereoselectivity mechanisms. Ligand modifications during drug development can be easily incorporated into these chiral graphs. In addition, these chiral graphs present an efficient tool for a deep dive into the enormous chemical structure space to enable sampling of unexplored structural scaffolds.     

Structural Analysis of Silver Doped Hydroxyapatite Nanopowders by Rietveld Refinement

Silver doped hydroxyapatite (AgHAP) nanopowders have been receiving great attention in orthopedic and dental implant applications owing to high bioactivity and antimicrobial properties. In the present study, AgHAP (Ca_10?xAg_x(PO₄)₆(OH)₂ where x = 0.01–0.05) nanopowders were synthesized by setting the atomic ratio of Ag/(Ca+Ag) at 1, 2, 3, 4, 5% and (Ca+Ag)/P molar ratio at 1.72 using sol–gel route. XRD and FTIR were employed to characterize phase and molecular structures of nanopowders, respectively. Crystallographic information of nanopowders was obtained using Rietveld refinement technique. It was observed that with the increase in doping percentage of Ag, AgHAP nanopowders remained biphasic i.e. composed of HAP and Ag₃PO₄ phases, whereas, inter-atomic distance between some selected atoms decreased, lattice parameters of HAP increased, lattice parameter of Ag₃PO₄ decreased and crystallite size of both HAP and Ag₃PO₄ phases increased. Crystallinity was maximum (60.1%) in nanopowder having Ag concentration of 3%. Type 2 Ca atoms were maximally replaced by Ag atoms. Difference in nominal and refined (Ca+Ag)/P molar ratio was observed. FTIR confirmed the formation of carbonated apatite in all nanopowders. Hence, this study presents a judicious approach to deeply analyze the influence of silver concentrations on structural parameters of AgHAP nanopowders.     

A BEM formulation for analysing the coupled stretching–bending problem of plates reinforced by rectangular beams with columns defined in the domain

In this work, a boundary element formulation to analyse plates reinforced by rectangular beams, with columns defined in the domain is proposed. The model is based on Kirchhoff hypothesis and the beams are not required to be displayed over the plate surface, therefore eccentricity effects are taken into account. The presented boundary element method formulation is derived by applying the reciprocity theorem to zoned plates, where beams are treated as thin sub-regions with larger rigidities. The integral representations derived for this complex structural element consider the bending and stretching effects of both structural elements working together. The standard equilibrium and compatibility conditions along interface are naturally imposed, being the bending tractions eliminated along interfaces. The in-plane tractions and the bending and in-plane displacements are approximated along the beam width, reducing the number of degrees of freedom. The columns are introduced into the formulation by considering domain points where tractions can be prescribed. Some examples are then shown to illustrate the accuracy of the formulation, comparing the obtained results with other numerical solutions.     

Effect of calcium and vitamin D2 fortification on quality characteristics of dahi

Two levels (500 and 600 ppm) of calcium (calcium phosphate and calcium citrate) along with vitamin D₂ (600 IU/L) were fortified in milk for dahi preparation. pH, water‐holding capacity and syneresis of fortified dahi were not affected significantly (P > 0.05). However, acetaldehyde content decreased and setting time increased upon fortification. Microbial count significantly (P < 0.05) decreased in calcium phosphate‐fortified dahi, whereas no difference was observed in calcium citrate‐fortified dahi. Firmness and viscosity decreased in calcium phosphate‐fortified dahi, whereas it increased in calcium citrate‐fortified dahi as compared to control. All dahi samples showed good sensory acceptability.     

A meta-heuristic-based energy efficient route modeling for EV on non-identical road surfaces

Neural Computing and Applications - Electric vehicles (EVs) have emerged as a fast-growing industry not only in India but all over the world due to their environment friendly and economic...     

Identifying the miRNA Signature Association with Aging-Related Senescence in Glioblastoma

Glioblastoma (GBM) is the most common malignant brain tumor and its malignant phenotypic characteristics are classified as grade IV tumors. Molecular interactions, such as protein–protein, protein–ncRNA, and protein–peptide interactions are crucial to transfer the signaling communications in cellular signaling pathways. Evidences suggest that signaling pathways of stem cells are also activated, which helps the propagation of GBM. Hence, it is important to identify a common signaling pathway that could be visible from multiple GBM gene expression data. microRNA signaling is considered important in GBM signaling, which needs further validation. We performed a high-throughput analysis using micro array expression profiles from 574 samples to explore the role of non-coding RNAs in the disease progression and unique signaling communication in GBM. A series of computational methods involving miRNA expression, gene ontology (GO) based gene enrichment, pathway mapping, and annotation from metabolic pathways databases, and network analysis were used for the analysis. Our study revealed the physiological roles of many known and novel miRNAs in cancer signaling, especially concerning signaling in cancer progression and proliferation. Overall, the results revealed a strong connection with stress induced senescence, significant miRNA targets for cell cycle arrest, and many common signaling pathways to GBM in the network.     

Overview on the Current Status of Hydrogen Energy Research and Development in India

The energy demand for the automobile and industrial sectors is increasing drastically worldwide. Conventional sources will no longer fulfil the growing energy demand and environmental pollution is a big concern. Thus, an alternative fuel for vehicles is highly required. The focus is shifted on renewable energy sources like hydrogen, which is abundant in nature. This review examines the continuous progress of hydrogen regarding production and storage techniques in India. Current studies and ongoing projects are summarized projecting the status of production, storage, and application of hydrogen. Challenges like infrastructure development, distribution, policies, cost, and public acceptance as obstacles for the commercialization of hydrogen-powered vehicles in the Indian market are analyzed.     

Geochemical phenomena between Utica-Point Pleasant shale and hydraulic fracturing fluid

This study evaluated geochemistry between the Utica-Point Pleasant shale and reservoir/hydraulic fracturing fluid mixtures under simulated reservoir conditions in a batch reactor system. Analytical techniques were utilized to monitor fluid composition with time along with pre- and post-trial shale microscopy and phase identification analyses. Formation of iron-based precipitate was evident through results from fluid and material analyses. Ferrous iron was the predominant iron form found in the aqueous phase, with oxidation to ferric iron and subsequent precipitate formation. Geochemical modeling further supported ferric iron was the favorable phase for precipitation.