Phase transition in L-alaninium oxalate by photoacoustics

Phase transition in L-alaninium oxalate is studied by using TG, DTA and photoacoustic spectroscopy. A sharp transition at 378 K by photoacoustics is observed whereas at the same temperature the endothermic energy change observed by TG and DTA is not very sharp. This is discussed in detail with reference to the other known data for the organic crystals.     

Note: Compact high voltage pulse transformer made using a capacitor bank assembled in the shape of primary

The experimental results of an air-core pulse transformer are presented, which is very compact (<10 Kg in weight) and is primed by a capacitor bank that is fabricated in such a way that the capacitor bank with its switch takes the shape of single-turn rectangular shaped primary of the transformer. A high voltage capacitor assembly (pulse-forming-line capacitor, PFL) of 5.1 nF is connected with the secondary of transformer. The transformer output voltage is 160 kV in its second peak appearing in less than 2 μS from the beginning of the capacitor discharge. The primary capacitor bank can be charged up to a maximum of 18 kV, with the voltage delivery of 360 kV in similar capacitive loads.     

Augmented photoelectrochemical response of CdS/ZnS quantum dots sensitized hematite photoelectrode

A visible light active and stable photoelectrode has been developed by depositing a passivating layer of ZnS QDs on CdS QDs sensitized hematite photoelectrode (Hematite‐CdS/ZnS) for PEC generation of hydrogen. Photoelectrochemical properties, in terms of stability and efficiency, have been investigated on the various hematite photoelectrodes sensitized with CdS QDs and CdS/ZnS QDs by varying number of SILAR cycles. I–V characteristics show that two layers of ZnS QDs deposited over three layers of CdS could enhance PEC response of hematite and efficiency by a factor of 3 and 11 respectively. Chronoamperometry measurement ensures that after adding a layer of ZnS QDs, CdS sensitized hematite film turns out to be a stable photoelectrode in the electrolyte. Prepared photoelectrodes have been characterized by XRD, SEM, HRTEM and UV–Vis spectrophotometer for various structural, morphological and optical properties to analyze PEC results. Mott–Schottky analysis and incident photon to current conversion efficiency (IPCE) measurements of sensitized hematite photoelectrode supported the improved PEC response of CdS/ZnS QDs sensitized hematite thin films. Copyright © 2016 John Wiley & Sons, Ltd.     

High‐performance electromagnetic interference shielding material based on an effective mixing protocol

A facile and economic method is developed for the fabrication of new lightweight materials with high electromagnetic interference (EMI) shielding performance, good mechanical properties and low electrical percolation threshold through melt mixing. Electrical properties, DC conductivity, EMI shielding performance and mechanical properties of poly(trimethylene terephthalate) (PTT)/multiwalled carbon nanotube (MWCNT) nanocomposites with varying filler loading of MWCNTs were investigated. High‐resolution transmission electron microscopy was used to determine the distribution of MWCNTs in the PTT matrix. The newly developed nanocomposites show excellent dielectric and EMI shielding properties. Theoretical electrical percolation threshold was achieved at 0.21 wt% loading of MWCNTs, due to the high aspect ratio and the three‐dimensional network formation of MWCNTs. Experimental DC conductivity values were compared with those of theoretical models such as the Voet, Bueche and Scarisbrick models, which showed good agreement. The PTT/3% MWCNT composite showed an EMI shielding value of ～38 dB (99.99% attenuation) with a sample thickness of 2 mm. Power balance was used to determine the actual contribution of reflection, absorption and transmission loss to the total EMI shielding value. The nanocomposites showed good tensile and impact properties and the composite with 2% MWCNTs exhibited an improvement in tensile strength of as much as 96%. © 2018 Society of Chemical Industry     

Dissolution and Solubility Behavior of Fenofibrate in Sodium Lauryl Sulfate Solutions

The solubility of fenofibrate in pH 6.8 McIlvaine buffers containing varying concentrations of sodium lauryl sulfate was determined. The dissolution behavior of fenofibrate was also examined in the same solutions with rotating disk experiments. It was observed that the enhancement in intrinsic dissolution rate was approximately 500-fold and the enhancement in solubility was approximately 2000-fold in a pH 6.8 buffer containing 2% (w/v) sodium lauryl sulfate compared to that in buffer alone. The micellar solubilization equilibrium coefficient (k*) was estimated from the solubility data and found to be 30884 ± 213 L/mol. The diffusivity for the free solute, 7.15 × 10^{? 6} cm²/s, was calculated using Schroeder's additive molal volume estimates and Hayduk-Laurie correlation. The diffusivity of the drug-loaded micelle, estimated from the experimental solubility and dissolution data and the calculated value for free solute diffusivity, was 0.86 × 10^{? 6} cm²/s. Thus, the much lower enhancement in dissolution of fenofibrate compared to its enhancement in solubility in surfactant solutions appears to be consistent with the contribution to the total transport due to enhanced micellar solubilization as well as a large decrease ( ～ 8-fold) in the diffusivity of the drug-loaded micelle.     

Use of the radiofrequency-intermodulation distortion technique to investigate intrinsic nonlinearity at the electrode-electrolyte interface

We report on investigations of nonlinear radiofrequency responses of electrolytes with Na(+) and Cl(-) ions placed within gold electrodes of a capacitor. The sample was part of a frequency-adjustable inductance-capacitance-resistance (LCR) parallel resonant circuit, and measurements were carried out using the two frequencies intermodulation distortion technique. We employed double layer model to analyze the observed nonlinearities and their dependence on ionic concentration. Electrode-electrolyte interface polarization was found to be a predominant cause of this intrinsic nonlinearity and to be dependent on electrolytic ion concentration. We also measured and calculated coefficients of resistive and capacitive components of the observed nonlinearity.     

Communication Maps: Exploring Energy Transport through Proteins and Water

Frequency-resolved communication maps provide a coarse-grained, global mapping of energy transport channels in a protein as a function of frequency of modes that carry energy. We illustrate the approach with a study of the homodimeric hemoglobin of Scapharca inaequivalvis, which exhibits cooperativity during ligand binding. We compare energy transport between the two hemes of the unliganded and oxygenated protein, which is mediated by water as well as residues forming a hydrogen-bonding network at the interface between the globules, and lies along the pathway for allosteric transitions observed in time-resolved X-ray studies. Non-equilibrium molecular simulations on energy transport from the heme corroborate the energy transport pathways identified by the communication maps.     

A robust face hallucination technique based on adaptive learning method

Position-patch based approaches have been proposed for single-image face hallucination. This paper models the face hallucination problem as a coefficient recovery problem with respect to an adaptive training set for improved noise robustness. The image-adaptive training set is constructed by corrupting a local training set of position-patches by adding specific amounts of noise depending on the input image noise level. In this proposed method, image denoising and super-resolution are simultaneously carried out to obtain superior results. Though the principle is general and can be extended to most super-resolution algorithms, we discuss this in context of existing locality-constrained representation (LcR) approach in order to compare their performances. It can be demonstrated that the proposed approach can quantitatively and qualitatively yield better results in high noisy environments.

     

Effect of relative humidity and light conditions on the oxidative stability of sunflower oil blends stabilised with synthetic and natural antioxidants

The effect of relative humidity (RH) and light conditions on the oxidative stability of sunflower oil (SO) stabilised with oleoresin rosemary + ascorbyl palmitate (SOR), sage + ascorbyl palmitate (SOS) and tertiary butyl hydroquinone (SOT) was investigated. The SO without additive (SOC) served as positive control. Oil samples were subjected to 3 RH (29%, 52% and 75%) and two light conditions (dark, D and fluorescent light (600 lx), L) at 60 °C for 7 days. The oxidative stability was monitored by peroxide value (PV), conjugated diene value (CDV), free fatty acids (FFAs) and Rancimat induction period (IP). A direct relationship was noted between RH and increase in PV, CDV and FFA levels irrespective of light conditions. The detrimental effect of light on the oxidative stability was prominently noted at higher RH (75%) which followed an order: SOC > SOT > SOR > SOS. The samples stored under lower RH (29% and 52%), and dark conditions were better stabilised than light‐exposed counterparts.