Dynamic behaviour of micaceous sand with varying mica content and its association with compactability, compressibility and monotonic shear response

The recently proposed, KAZE image feature detection and description algorithm (Alcantarilla et al. in Proceedings of the British machine vision conference. LNCS, vol 7577, no 6, pp 13.1–13.11, 2013) offers significantly improved robustness in comparison to conventional algorithms like SIFT (scale-invariant feature transform) and SURF (speeded-up robust features). The improved robustness comes at a significant computational cost, however, limiting its use for many applications. We report a GPU acceleration of the KAZE algorithm that is significantly faster than its CPU counterpart. Unlike previous reports, our acceleration does not resort to binary descriptors and can serve as a drop-in replacement for CPU-KAZE, SIFT, SURF etc. By achieving nearly tenfold speedup (for a 1920 by 1200 sized image, our Compute Unified Device Architecture (CUDA)-C implementation took around 245 ms on a single Cohesionless soils are highly susceptible to liquefaction under dynamic loading with high-strain amplitude simulating earthquake loading conditions. The presence of flaky mica particles among spherical sand influences the microscopic particle level mechanisms due to complex geometric arrangements caused by bridging, ordering and pore filling phenomena. Such variations substantially affect the compactability, compressibility and shear strength behaviour under monotonic and dynamic loading conditions. The current experimental investigations evaluated the effect of mica content on dynamic behaviour of micaceous sand through a series of strain-controlled cyclic triaxial tests at constant frequency and double axial strain amplitude of 0.5 Hz and 0.6% per cycle. The variation in dynamic parameters such as shear modulus and damping was determined at different mica contents along with cyclic stiffness degradation. Cumulative dissipated strain energy was also estimated to understand the contact-force networks of varying sand and mica matrix from sand-sand to mica-mica through sand-mica particle contact.by P. Seethalakshmi and Ajanta Sacha

Chemical method for evaluating catalytic turnover frequencies (TOF) of moderate to slow H2 oxidation electrocatalysts

Hydrogen has emerged as a long-term option for storing energy from renewable resources and has led the scientific community to develop enzyme-inspired catalysts for hydrogen oxidation and production. One of the most productive families of catalysts for H2 oxidation is the pendant amine containing bis(diphosphine)nickel catalysts. Many derivatives of these nickel complexes have been prepared with varying peripheral functionalities to understand their structure-function relationship. Electrocatalysis is currently utilized as the primary tool to measure the catalytic turnover frequencies (TOFs) of these complexes; however, it does not allow accurate determination of TOFs for slow (<1 s-1) to moderately active (<1-10 s-1) catalysts, and for the slowest catalysts, it can be difficult to determine if they are turning over at all. Further, it does not allow the determination of the TOF in bulk solution. In this work, we demonstrate that a redox chemical procedure involving a change between ferrocenium cation and ferrocene can be utilized to monitor H2 oxidation catalysts. The ferrocenium cation reoxidizes the reduced nickel catalyst stoichiometrically in the presence of H2. The change of ferrocenium cation to ferrocene can be monitored in both organic and aqueous solvents via either optical spectroscopy or NMR spectroscopy. Thus, this chemical method complements the existing electrocatalytic procedure and may help to unravel the intricate details of even the slowest H2 oxidation catalysts.by Dutta Arnab and Wendy J. Sha

Catalytic regioselective ?-Methylenation of ?,?-Unsaturated aldehydes using formaldehyde via vinylogous aldol condensation

Formaldehyde is used as a one-carbon electrophile(1) in several organic transformations to functionalize aldehydes,(2) ketones,(3) amines,(4) and alkenes.(1c,5) However, the reaction of formaldehyde with α,β-unsaturated aldehydes has rarely been studied.(6) In 1953, Pummerer and co-workers tested the reaction of formaldehyde with crotonaldehyde catalyzed by NaOAc and found the formation of a α-methylenated product that further self-reacted to produce a cycloadduct via Diels–Alder reaction (Scheme 1).(6a) After a decade, Farberov and co-workers carefully chose an α-methylated α,β-unsaturated aldehyde (to avoid α-functionalization) for the Mannich reaction with diethylammonium chloride and formaldehyde to obtain a γ-aminomethylated product that underwent thermal elimination at high temperature and high vacuum to give a γ-methylenated product.(6b) Though the unsaturated carbonyl compounds such as ketones, esters, and lactones have been extensively studied for the vinylogous aldol reaction involving silyl ethers(7a−c) and dienamine(7d) intermediates, α,β-unsaturated aldehydes have rarely been explored.(8) To the best of our knowledge, there is no report in the literature for the vinylogous aldol reaction (or condensation) of formaldehyde with α,β-unsaturated aldehydes.by Mahesh S. Kutwal, Sachin Dev, and Chandrakumar Appaye

On Conditional Simulation of Spatially Varying Rotational Ground Motion

Authors elsewhere reported two frameworks for conditional simulation of spatially varying translational ground motion, namely, (i) cross-spectral density (CSD) based framework and (ii) auto-spectral density (ASD) based framework. This paper investigates the applicability of both the frameworks for rotational components. Rotational components are extracted here using one of the Single Station Procedures reported in the literature. Spatially varying rotational ground motion for a future event is explored using a coherency model calibrated against a past event and an estimate of ASD of the seed (rotational) ground motion. Choice of representation of ASD is also investigated.by Gopala Krishna Rodda and Dhiman Bas

Numerical modeling of diffusion-based peritectic solidification in iron carbon system and experimental validation

Continuous casting of high-strength steels is challenging owing to peritectic phase transformation during solidification. This transformation is reported to be either diffusion controlled or “massive” like. The experimental evidence suggests that constant thermal gradients lead to diffusion-controlled phenomena, whereas the concentric solidification technique induces massive transformation. Diffusion-controlled peritectic solidification is more desirable during continuous casting to ensure a suitable cast quality compared with massive transformation. Accordingly, the authors demonstrate a general one-dimensional numerical modeling of the solidification process in steel by incorporating a diffusion-controlled peritectic phase transformation. The model is dynamically linked with the FactSage thermodynamic database through ChemAppV 7.1.4 library for input of accurate thermodynamic data. The modeling details are presented for a binary Fe-C system, and the results are compared with the experimental data available in the literature. The growth and dissolution of phases are accurately predicted as a function of composition and cooling rate.by Ipsita Madhu Mita Das, Nishant Kumar and Manas Paliwa

Small molecule fluorescent probes for G-Quadruplex visualization as potential cancer theranostic agents

G-quadruplexes have gained prominence over the past two decades for their role in gene regulation, control of anti-tumour activity and ageing. The physiological relevance and significance of these non-canonical structures in the context of cancer has been reviewed several times. Putative roles of G-quadruplexes in cancer prognosis and pathogenesis have spurred the search for small molecule ligands that are capable of binding and modulating the effect of such structures. On a related theme, small molecule fluorescent probes have emerged that are capable of selective recognition of G-quadruplex structures. These have opened up the possibility of direct visualization and tracking of such structures. In this review we outline recent developments on G-quadruplex specific small molecule fluorescent probes for visualizing G-quadruplexes. The molecules represent a variety of structural scaffolds, mechanism of quadruplex-recognition and fluorescence signal transduction. Quadruplex selectivity and in vivo imaging potential of these molecules places them uniquely as quadruplex-theranostic agents in the predominantly cancer therapeutic context of quadruplex-selective ligands.by Pallavi Chilka, Nakshi Desai, and Bhaskar Datta

Accelerated seam carving for image retargeting

by Diptiben Patel and Shanmuganathan Rama

Montmorillonite clay and humic acid modulate the behavior of copper oxide nanoparticles in aqueous environment and induces developmental defects in zebrafish embryo

Copper oxide nanoparticles (CuO NPs) is one of the most commonly used metal oxide nanoparticles for commercial and industrial products. An increase in the manufacturing and use of the CuO NPs based products has increased the likelihood of their release into the aquatic environment. This has attracted major attention among researchers to explore their impact in human as well as environmental systems. CuO NPs, once released into the environment interact with the biotic and abiotic constituents of the ecosystem. Hence the objective of the study was to provide a holistic understanding of the effect of abiotic factors on the stability and aggregation of CuO NPs and its correlation with their effect on the development of zebrafish embryo. It has been observed that the bioavailability of CuO NPs decrease in presence of humic acid (HA) and heteroagglomeration of CuO NPs occurs with clay minerals. CuO NPs, CuO NPs + HA and CuO NPs + Clay significantly altered the expression of genes involved in development of dorsoventral axis and neural network of zebrafish embryos. However, the presence of HA with clay showed protective effect on zebrafish embryo development. These findings provide new insights into the interaction of NPs with abiotic factors and combined effects of such complexes on developing zebrafish embryos genetic markers.by Krupa Kansara, Archini Paruthi, Superb K.Misra, Ajay S. Karakotia and Ashutosh Kuma

A nanotube-supported dicopper complex enhances Pt-free molecular H2/Air fuel cells

A dinuclear copper complex mimicking the active site of copper oxidase was designed and ?-stacked on a carbon nanotube (CNT) electrode thanks to pendent pyrene groups. The high oxygen reduction reaction activity of such CNT-supported dicopper complexes in pH 4 electrolyte allowed the construction of a Pt-free hydrogen/air fuel cell using bioinspired nickel bis-diphosphine complexes immobilized onto CNT at the anode, with an order-of-magnitude improvement of the performance compared to previous literature data. This bioinspired nickel- and copper-based H2/air fuel cell reaches a maximum power density of 0.15 mW cm?2 at 0.25 V and pH 4.by by Arnab Dutta et al

Insilico characterization of gamma secretase activating protein (GSAP) and its involvement in alzheimer's disease

by Kapilkumar MehetaM.Tech