Study of the Effect of Different Nucleating Agents On Lithium Alumino-Silicate Glass-Ceramic System

Lithium AluminoSilicate (LAS) Glass ceramic (GC) finds use in kitchenware, cooktop panels and telescope mirror because of its characteristic of very low and sometime zero thermal expansion coefficient (TEC) in the application temperature range. In this project work, conventional melt-quenching technique has been used for the development of the LAS base glass. After controlled crystallization, LAS GC has been developed using titania and/ zirconia as a nucleating agent and their effect has been studied in the presence of yittria. Here the yittria content has been varied from 1-3 wt% with corresponding variation in titania (2-4 wt%) or zirconia (2-4 wt%). Effects of temperature and time on crystallization have also been studied followed by the effect of crystallization on thermal expansion co-efficient of the developed glass ceramics. Developed crystalline phases were â-Spodumene and â-quartz solid solution (ss) which has been authenticated by X-ray diffractometer. TEC of the GC has been measured and studied using Dilatometer in the temperature range of 25oC to 750oC and its surface hardness has been measured at 0.5Kgf using Vickers indentation method

First principles investigation of anionic redox in bisulfate lithium battery cathodes

The search for an alternative high-voltage polyanionic cathode material for Li-ion batteries is vital to improve the energy densities beyond the state-of-the-art, where sulfate frameworks form an important class of high-voltage cathode materials due to the strong inductive effect of the S$^{6+}$ ion. Here, we have investigated the mechanism of cationic and/or anionic redox in Li$_x$M(SO$_4$)$_2$ frameworks (M = Mn, Fe, Co, and Ni and 0 $\leq$ x $\leq$ 2) using density functional calculations. Specifically, we have used a combination of Hubbard $U$ corrected strongly constrained and appropriately normed (SCAN+$U$) and generalized gradient approximation (GGA+$U$) functionals to explore the thermodynamic (polymorph stability), electrochemical (intercalation voltage), geometric (bond lengths), and electronic (band gaps, magnetic moments, charge populations, etc.) properties of the bisulfate frameworks considered. Importantly, we find that the anionic (cationic) redox process is dominant throughout delithiation in the Ni (Mn) bisulfate, as verified using our calculated projected density of states, bond lengths, and on-site magnetic moments. On the other hand, in Fe and Co bisulfates, cationic redox dominates the initial delithiation (1 $\leq$ x $\leq$ 2), while anionic redox dominates subsequent delithiation (0 $\leq$ x $\leq$ 2). In addition, evaluation of the crystal overlap Hamilton population reveals insignificant bonding between oxidizing O atoms throughout the delithiation process in the Ni bisulfate, indicating robust battery performance that is resistant to irreversible oxygen evolution. Finally, we observe both GGA+$U$ and SCAN+$U$ predictions are in qualitative agreement for the various properties predicted. Our work should open new avenues for exploring lattice oxygen redox in novel high voltage polyanionic cathodes, especially using the SCAN+$U$ functional.Comment: Draft and supporting information included, 40 pages tota

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

The 2015 Gorkha earthquake (M-w 7.8) occurred by thrust faulting on a similar to 150 km long and similar to 70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the main-shock rupture and source mechanism of aftershocks. The main-shock initiated similar to 80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards along similar to 117 degrees. azimuth for a duration of similar to 70 s, with varying rupture velocity on a heterogeneous fault surface. The main-shock has been modelled using four subevents, propagating from west-to-east. The first subevent (0-20 s) ruptured at a velocity of similar to 3.5 km s(-1) on a similar to 6 degrees N dipping flat segment of the MHT with thrust motion. The second subevent (20-35 s) ruptured a similar to 18 degrees. Wdipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km s(-1) to 2.5 km s(-1), as a result of updip propagation of the rupture. The third subevent (35-50 s) ruptured a similar to 7 degrees. N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth subevent (50-70 s) occurred by left-lateral strike-slip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the main-shock rupture. Eastward stress build-up following the main-shock resulted in the largest aftershock (M-w 7.3), which occurred on the MHT, immediately east of the main-shock rupture. Source mechanisms of moderate aftershocks reveal stress adjustment at the edges of the main-shock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.Peer reviewe

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

The Mw 7.8 Gorkha (Nepal) earthquake on 2015 April 25 initiated ∼80 km northwest of the capital city of Katmandu and ruptured ∼150 km of the frictionally locked downdip segment of the Main Himalayan Thrust (MHT) beneath the central Nepal Himalaya (Avouac et al. 2015). The earthquake resulted in ∼4 m of average slip of the Himalayan Mountains over the Indian Plate in the SSW direction (Mitra et al. 2015). The main-shock fault spanned between the meisoseismal zone of the 1505 (Mw > 8.5) earthquake to its west (Kumar et al. 2006) and the rupture zone of the 1934 (Mw 8.2–8.4) Nepal earthquake to its east (Bilham & Wallace 2005; Sapkota et al. 2013). The last known great earthquake in this region of Nepal occurred in 1833 (M ∼7.5) (Ambraseys & Douglas 2004) and has a significant overlap with the rupture area of the Gorkha main-shock (Adhikari et al. 2015). The main-shock was followed by a series of moderate-to-strong aftershocks, the largest one (Mw 7.3) occurred 18 d after the main-shock, on 2015 May 12 (Fig. 1). Albeit the loss of life and property inflicted by this damaging earthquake and its aftershocks, it has provided an unprecedented opportunity to study the source properties of Himalayan mega-thrust earthquake and its relationship to the geometry of the MHT, which, so far, is poorly understood

Synthesis of macromolecular systems via lipase catalyzed biocatalytic reactions: applications and future perspectives

Enzymes, being remarkable catalysts, are capable of accepting a wide range of complex molecules as substrates and catalyze a variety of reactions with a high degree of chemo-, stereo- and regioselectivity in most of the reactions. Biocatalysis can be used in both simple and complex chemical transformations without the need for tedious protection and deprotection chemistry that is very common in traditional organic synthesis. This current review highlights the applicability of one class of biocatalysts viz. ‘‘lipases’’ in synthetic transformations, the resolution of pharmaceutically important small molecules including polyphenols, amides, nucleosides and their precursors, the development of macromolecular systems (and their applications as drug/gene carriers), flame retardants, polymeric antioxidants and nanocrystalline solar cells, etc

Chemoenzymatic synthesis, nanotization and anti- aspergillus activity of optically enriched fluconazole analogues

Despite recent advances in diagnostic and therapeutic advances in antifungal research, aspergillosis still remains a leading cause of morbidity and mortality. One strategy to address this problem is to enhance the activity spectrum of known antifungals, and we now report the first successful application of Candida antarctica lipase (CAL) for the preparation of optically enriched fluconazole analogs. Anti-Aspergillus activity was observed for an optically enriched derivative, (-)-S-2-(2’ ,4’ -difluorophenyl)-1-hexyl-amino-3-(1‴,2‴,4‴) triazol-1‴-yl-propan-2-ol, which exhibits MIC values of 15.6 μg/mL and 7.8 μg/disc in microbroth dilution and disc diffusion assays, respectively. This compound is tolerated by mammalian erythrocytes and cell lines (A549 and U87) at concentrations of up to 1000 μg/mL. When incorporated into dextran nanoparticles, the novel, optically enriched fluconazole analog exhibited improved antifungal activity against Aspergillus fumigatus (MIC = 1.63 μg/mL). These results not only demonstrate the ability of biocatalytic approaches to yield novel, optically enriched fluconazole derivatives but also suggest that enantiomerically pure fluconazole derivatives, and their nanotised counterparts, exhibiting anti-Aspergillus activity may have reduced toxicity

Facebook Application Development with Graph API Cookbook

Written in a cookbook style, this book offers solutions using a recipe-based approach. Each recipe contains step-by-step instructions followed by an analysis of what was done in each task and other useful information. The cookbook approach means you can dive into whatever recipes you want in no particular order. The book provides tips and tricks to the most common problems and scenarios faced in Facebook Application Development. This book is written for Facebook developers ranging from novice to expert. It uses PHP, HTML and jQuery, the most commonly used platforms, to build applications in F