Study on Ag doping in congruent lithium niobate crystal

Ag doped congruent lithium niobate crystal has been demonstrated as a promising photorefractive material for holographic recording applications. In this paper, the effects of Ag doping on the lattice structure and the optical properties were investigated by XRD, Raman spectroscopy and optical absorption characterization. The Ag ion was proposed to occupy Li-sites and results in lattice deformation. The band gap became narrower and an absorption band at near 500 nm was created with Ag doping. High temperature annealing and UV irradiation were performed to further understand the Ag doping effects.     

Dependence of thermotropic mesomorphism on lateral nitro group

A novel homologous series RO-C₆H₄-COO-C₆H₃-(NO₂)-CO-CH?CH-C₆H₄OC₁₈H₃₇(n) para of chalconyl ester derivatives have been synthesized and studied with view to understanding the effect of an ortho substituted nitro group on thermotropic liquid crystal (LC) behavior. The novel homologous series consists of thirteen homologues (C₁ to C₁₈). The C₁ to C₄ homologues are nonliquid crystal (NLC) and the rest of the homologues (C₅ to C₁₈) homologues are enantiotropically nematogenic without exhibition of a smectic phase even in the monotropic condition. Transition temperatures were determined by an optical polarizing microscope (POM) equipped with a heating stage. Texture of nematic phase are threaded or Schlieren. Analytical, thermal and spectral data supported molecular structure of homologues. Thermal stability for nematic is 147.1°C whose mesophase lengths vary between 16.0 and 32.0°C the C₇ and C₁₈ homologues, respectively, and their mesogenic exhibition range between 96.0 and 166.0°C. Thus, the present novel series is middle ordered melting type, Group efficiency order is derived from comparative study of structurally similar series. The transition curves of a phase diagram behaved in normal manner except C₁₀ and C₁₆ homologues. Odd-even effect is observed for N-I transition curve. Group efficiency order derived is: -OC₁₂H₂₅ (n) > -OC₁₈H₃₇ (n) > -OC₁₈H₃₇ (n).     

Enhancement of lipase activity in non-aqueous media upon immobilization on multi-walled carbon nanotubes

Background  

Immobilization of biologically active proteins on nanosized surfaces is a key process in bionanofabrication. Carbon nanotubes with their high surface areas, as well as useful electronic, thermal and mechanical properties, constitute important building blocks in the fabrication of novel functional materials.     

Potential of Gelatin‐Zinc Oxide Nanocomposite as Ascorbic Acid Sensor

We report on the studies relating to fabrication of gelatin B (GB) and zinc oxide (ZnO) based nanocomposite (GB‐ZnO) film deposited on indium‐tin‐oxide (ITO) glass plate, and used for the immobilization of ascorbate oxidase (AsOx) which was further used for ascorbic acid (AA) detection. The structural and morphological studies of GB‐ZnO, and AsOx/GB‐ZnO/ITO bioelectrodes were carried out using XRD, SEM and FTIR techniques. This bioelectrode showed a broad range of linearity (5–500 mg/dL), low detection limit (1 mg/dL), higher sensitivity (0.106 µA mg/dLcm^?2) and low value of the apparent Michaelis? Menten constant (K_m^app=0.35 mg/dL) for AA. Efforts are being made to utilize this electrode for sensing AA in real samples in a bid to develop a strip based sensor.     

Damage smoothing effects in a delocalized rate sensitivity model for metals

It has been long time established that application of damage delocalization method to softening constitutive models yields numerical results that are independent of the size of the finite element. However, the prediction of real-world large and small scale problems using the delocalization method remains in its infancy. One of the drawbacks encountered is that the predicted load versus displacement curve suddenly drops, as a result of excessive smoothing of the damage. The present paper studies this unwanted effect for a delocalized plasticity/damage model for metallic materials. We use some theoretical arguments to explain the failure of the delocalized model considered, following which a simple remedy is proposed to deal with it. Future works involve the numerical implementation of the new version of the delocalized model in order to assess its ability to reproduce real-world problems.     

On kinematic,thermodynamic, and kinetic coupling of a damage theory for polycrystalline material

The paper proposes a new consistent formulation of polycrystalline finite-strain elasto-plasticity coupling kinematics and thermodynamics with damage using an extended multiplicative decomposition of the deformation gradient that accounts for temperature effects. The macroscopic deformation gradient comprises four terms: thermal deformation associated with the thermal expansion, the deviatoric plastic deformation attributed to the history of dislocation glide/movement, the volumetric deformation gradient associated with dissipative volume change of the material, and the elastic or recoverable deformation associated with the lattice rotation/stretch. Such a macroscopic decomposition of the deformation gradient is physically motivated by the mechanisms underlying lattice deformation, plastic flow, and evolution of damage in polycrystalline materials. It is shown that prescribing plasticity and damage evolution equations in their physical intermediate configurations leads to physically justified evolution equations in the current configuration. In the past, these equations have been modified in order to represent experimentally observed behavior with regard to damage evolution, whereas in this paper, these modifications appear naturally through mappings by the multiplicative decomposition of the deformation gradient. The prescribed kinematics captures precisely the damage deformation (of any rank) and does not require introducing a fictitious undamaged configuration or mechanically equivalent of the real damaged configuration as used in the past.     

Applications of metal–organic framework-based bioelectrodes

Metal–organic frameworks (MOFs) are an emerging class of porous nanomaterials that have opened new research possibilities. The inherent characteristics of MOFs such as their large surface area, high porosity, tunable pore size, stability, facile synthetic strategies and catalytic nature have made them promising materials for enormous number of applications, including fuel storage, energy conversion, separation, and gas purification. Recently, their high potential as ideal platforms for biomolecule immobilization has been discovered. MOF-enzyme-based materials have attracted the attention of researchers from all fields with the expansion of MOFs development, paving way for the fabrication of bioelectrochemical devices with unique characteristics. MOFs-based bioelectrodes have steadily gained interest, wherein MOFs can be utilized for improved biomolecule immobilization, electrolyte membranes, fuel storage, biocatalysis and biosensing. Likewise, applications of MOFs in point-of-care diagnostics, including self-powered biosensors, are exponentially increasing. This paper reviews the current trends in the fabrication of MOFs-based bioelectrodes with emphasis on their applications in biosensors and biofuel cells.

Metal–organic frameworks based bioelectrodes.     

Quantification of Lupeol in Polyherbal Formulation by High-Performance Thin-Layer Chromatography Method Using Design of Experiments as a Tool to Assess Optimization of Method Development and Extraction Efficiency

JPC – Journal of Planar Chromatography – Modern TLC - A simple, specific, and quantitative high-performance thin-layer chromatographic (HPTLC) method has been developed for the...