Paramagnetic nature of Mn doped ZnS nano particles in opto electronic device application

Manganese (Mn²⁺) doped ZnS nano sized powder was prepared by co precipitation method with different concentration from 1 to 5 %. The X-ray diffraction pattern indicates that the prepared powders are in cubic structure with the crystallite sizes lie in the range of 10–12 nm. Diffuse reflectance studies enlightens that an increment in the band gap (3.38–3.55 eV) with increasing dopant. The morphology and size of the sample could be intuitively determined by field emission scanning electron microscope and it shows that ZnS and Mn doped ZnS nanoparticles are appeared as spherical shape. The replacement of Zn by Mn is confirmed by energy dispersive analysis. TEM images confirm the spherical shape of the nanoparticles and SAED images exhibit the crystalline nature and confirm the cubic nature of the synthesized samples. The prepared luminescent nanoparticles of Mn doped ZnS have emission peak at around 617 nm. The symmetry and electronic structure of the Mn doped samples are studied with electron paramagnetic resonance.The paramagnetic nature of Mn doped ZnS nano particles are validated by using vibrating sample magnetometer spectra at room temperature. Thermal analysis measurement of the samples shows that the thermal stability of Mn doped ZnS is higher than the undoped ZnS. This corroborates that ZnS:Mn doping is attributed to the removal of water and it enhanced the crystallinity.     

Mobile application-based computer-aided diagnosis of skin tumours from dermal images

Skin tumour is defined as the enormous growth of cells in the skin. The aim is to design standalone application for diagnosis of skin tumours. The dermal images of three different types obtained from the authorized PH2 database are used to analyse the defined image processing algorithm. In this algorithm, pre-processing was performed to remove hair cells. Contour-based level set is used to segment lesion from which clinical and morphological features are extracted for classification. Significant features are obtained with the feature selection technique, Random subset. Classification is performed with three classifiers. The efficiency of the classifier obtained with different trials of classification is analysed with the ANOVA test. With these results, the Multiclass Support vector machine was configured as a suitable classifier to categorize dermal images. Therefore, an application is developed for the analysis of images acquired through mobile with the help of a magnification set-up. Thus, extracted features, segmented and original images are transferred to a database for storage.     

Mesoporous Pt–Ni catalyst and their electro catalytic activity towards methanol oxidation

Mesoporous Pt/Ni architecture has been prepared by template assisted electrochemical deposition of Pt–Ni over anodized aluminum oxide template followed by controlled de-alloying with nitric acid. Surface characteristics of the ordered bimetallic mesoporous Pt/Ni structure were systematically characterized through XRD, SEM, AFM and XPS analyses. It is designated by XPS analysis that presence of Ni significantly modifies surface characteristics and electronic states of Pt accompanied with a downshift in the d-band character of Pt. Mesoporous morphology is highly beneficial to offer readily accessible Pt catalytic sites for methanol oxidation reaction. The prepared bimetallic Pt/Ni was used as electro catalyst for DMFC. Comparison of electrocatalytic activity of bimetallic mesoporous Pt/Ni with bimetallic smooth Pt/Ni was interrogated using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy analyses. Distinctly enhanced electrocatalytic activity with improved CO tolerance associated with bimetallic mesoporous Pt/Ni electrode towards methanol oxidation stems from a synergy existing between mesoporous structure with bi-metallic composition.     

Biocomposite proton‐exchange membrane electrolytes for direct methanol fuel cells

Poly(vinyl alcohol) (PVA)‐amino acid (AA) biocomposite membranes are prepared by blending PVA with AAs such as glycine, lysine (LY), and phenyl alanine followed by in situ crosslinking with citric acid (CA) and explored as a new class of biocomposite membrane electrolytes for direct methanol fuel cells (DMFCs). CA crosslinks with PVA through esterification offers adequate chemical, thermal, and morphological stability thereby produces methanol‐obstructing close‐packed polymeric network. These biocomposite membranes are characterized in terms of mechanical, thermal, sorption, and proton‐conducting properties. Hydrophilic nature of AA zwitterions significantly facilitates proton conduction and CA crosslinking mitigates methanol crossover through establishing appropriate balance between hydrophilic/hydrophobic domains. The rational design of membrane microstructure with proper arrangement of hydrophobic/hydrophilic domains is a key to enhance electrochemical selectivity of PVA‐AA/CA biocomposite membranes. Biocomposite membrane comprising LY exhibits nearly threefold higher electrochemical selectivity in relation to PVA/CA blend membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43514.     

CRITICAL ANALYSIS OF WIND FARMS FOR SUSTAINABLE GENERATION

A critical analysis on wind farms has been carried out to improve the performance and reliability of wind energy system. The effect of its improvement has been studied with the Optimal Renewable Energy Mathematical (OREM) model which is developed for sustainable generation in India. The performance and reliability of the wind turbine generators have been evaluated in a demonstration windfarm (6 MW) in India. The windfarm is situated in Kayathar, a village in the south of Tamil Nadu State. The average technical availability, real availability and capacity factor have been analysed from 1991 to 1995 and they are found to be 92%, 54% and 19% respectively. Fault analysis for grid failures has been done using pareto analysis. The analysis indicates that when grid drop failures are reduced by 50%, the overall reduction in the frequency of faults would be 35.2%, which is significant. The reliability analysis has also been done for the wind turbine generator. The failure rate is high to an extent of 6.7×10⁻⁵ h⁻¹ in the case of a yaw control defect and the factor of reliability is found to be 0.5 at 10 000 h. The OREM model developed reveals that when the reliability factor of wind energy system is improved from 0.5 to 0.9 then the utilisation of wind energy would be increased by 82%.     

Morphological edge detection and brain tumor segmentation in Magnetic Resonance (MR) images based on region growing and performance evaluation of modified Fuzzy C-Means (FCM) algorithm

Multimedia Tools and Applications - The medical image processing has become indispensable with an increased demand for systematic and efficient detection of brain tumor in a short period of time....     

Validation and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw using LC-MS/MS

An efficient analytical method was developed and validated using a modified QuEChERS method and LC-MS/MS for the detection and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw. The samples were extracted using acetonitrile and cleaned up by dispersive solid-phase extraction. Validation based on five fortification levels showed good recoveries of neonicotinoids ranging from 75% to 116 % and 60% to 105 % for rice whole grain and straw, respectively. The precision ranged between 3% and 17 %, and 2% and 10 % for grain and straw, respectively. The limit of detection was from 0.007 to 0.0084 mg kg^?1 and 0.005 to 0.15 mg kg^?1 and the limit of quantification was in the range of 0.024–0.028 mg kg^?1 and 0.016–0.051 mg kg^?1 for rice whole grain and rice straw, respectively. Monitoring of farm gate samples indicated that, out of 24 samples, 1 rice whole grain sample was contaminated with thiamethoxam residues (0.07 mg kg^?1).     

Enhancement of wettability and antibiotic loading/release of hydroxyapatite thin film modified by 100 MeV Ag ion irradiation

The effect of swift heavy 100 MeV Ag⁷⁺ ions irradiation was studied on hydroxyapatite (HAp) thin film prepared by pulsed laser deposition technique (PLD). The GIXRD analysis confirmed the absence of any phase in the HAp phase due to irradiation. In addition, there was a considerable decrease in crystallinity and crystallite size on irradiation. There was no significant variation in the stoichiometry of the irradiated films. Irradiation seemed to decrease the optical band gap energy of HAp thin films. The surface roughness, wettability and bioactivity were improved on irradiation of the samples. Amount of amoxicillin loading/release increased (10%) in ion beam irradiated (1 × 10¹² ions cm⁻²) sample. Irradiated sample showed fast rate of amoxicillin (AMX) release than the pristine. Bactericidal effect was found to increase on irradiation. Surface modified and antibiotics incorporated HAp coated titanium implants may be used to prevent post-surgical infections and to promote bone-bonding of orthopedic devices.     

Evidence for quantum confinement effects in CdSe/ZnSe multilayer thin films prepared by the physical vapor deposition method

CdSe/ZnSe heterostructure multilayer thin films were prepared with different sublayer thicknesses of CdSe using the physical vapor deposition method. X-ray diffraction studies were used to calculate the average size of the particles and confirmed the (1 1 1) plane of ZnSe. Due to the stacking of alternate CdSe and ZnSe layers, stress was created in the multilayer systems. This results in quantum size effects. Experimentally measured energy values from (hν) vs. (αhν)² dependence confirm the presence of spin–orbit split in the valence band of CdSe. The calculated band gap energies are greater than that of bulk CdSe. Crystallite sizes (12–4 nm) were calculated based on the predictions of the effective mass approximation model (i.e. Brus model). Results show that the diameters of crystallites are smaller than the Bohr exciton diameter (11.2 nm) of CdSe. Upon particle size decrease, the photoluminescence peak is shifted from the green region to the blue region. Analysis shows that the sublayer thickness of CdSe material changes the properties of CdSe/ZnSe multilayer systems.     

复合式膜生物反应器在制革污水处理中的应用发展

考察了复合式膜生物反应器(HMBR),即电絮凝、生化和微滤过程,对制革污水中的COD和色度的去除效果。分析了电流密度和pH值在电絮凝过程中的影响,并优化了电絮凝过程。将优化后的电絮凝过程和活性污泥法(ASP)、末端微滤(MF)相结合,应用于制革污水处理中。结果表明:复合过程可以有效提升污水的处理质量。对比膜生物反应器(MBR)和HMBR的处理效果,HMBR的最大COD去除率和脱色率分别为90.2%和92.75%,而MBR的最大COD去除率和脱色率分别为72.69%和75.82%。使用SEM-EDAX分析HMBR过程中附着在膜表面的滤饼层,表明将MBR和电絮凝法结合后,膜上的污垢显著减少。