Photoelectrochemically active surfactant free single step hydrothermal mediated titanium dioxide nanorods

Titanium dioxide (TiO₂) nanorods have been successfully synthesized by a simple and cost-effective hydrothermal deposition method onto the conducting glass substrates. Effect of reaction temperature on the growth of TiO₂ nanorods have been investigated by varying the reaction temperature from 140 to 200 °C. The optical, structural, compositional, morphological properties of the synthesized films are studied. X-ray diffraction patterns reveal the formation of polycrystalline TiO₂ with the tetragonal crystal structure possessing rutile phase. The chemical composition and valence states of the constituent elements were analysed by X-ray photoelectron spectroscopy. Field emission scanning electron microscopy images shows the formation of nanorod-like structure with variation in diameter. The optical band gap energy was found to increase from 3.07 to 3.15 eV with the increase in reaction temperature exhibiting a blue shift. The films were photo electrochemically active with the maximum current density of 216 µA/cm² for the sample prepared at 180 °C.     

Design of a novel biohythane process with high H2 and CH4 production rates

A biohythane process based on wheat straw including: i) pretreatment, ii) H₂ production using Caldicellulosiruptor saccharolyticus, iii) CH₄ production using an undefined consortium, and iv) gas upgrading using an amine solution, was assessed through process modelling including cost and energy analysis. According to simulations, a biohythane gas with the composition 46–57% H₂, 43–54% CH₄ and 0.4% CO₂, could be produced at high production rates (2.8–6.1 L/L/d), with 93% chemical oxygen demand (COD) reduction, and a net energy yield of 7.4–7.7 kJ/g dry straw. The model was calibrated and verified using experimental data from dark fermentation (DF) of wheat straw hydrolysate, and anaerobic digestion of DF effluent. In addition, the effect of gas recirculation was investigated by both wet experiments and simulation. Sparging improved H₂ productivities and yields, but negatively affected the net energy gain and cost of the overall process.     

Apricot kernel characterization,oil extraction,and its utilization: a review

Food Science and Biotechnology - Apricot (Prunus armeniaca L.) kernels, one of the economical stone fruit kernels, are utilized worldwide for edible, cosmetic, and medicinal purposes. Oil from the...     

Mechanism of luminescence in CaS:Bi phosphor

Calcium sulphide phosphors are prepared with bismuth as an activating impurity. Absorption and emission spectra, phosphorescence and thermoluminescence are studied. Correlation is made between results of phosphorescence and thermoluminescence studies carried out at the ambient temperature and below. A suitable model is proposed to explain the luminescence in CaS:Bi phosphors excited by 3650 Å radiation.     

What About Spectrum Opportunities in ‘Angle’ Dimension for Dynamic Spectrum Access in Cognitive Radio Network context? A new Paradigm in Spectrum Sensing

The cognitive radio technology is the new paradigm to fulfill ever increasing need of bandwidth ultimately the radio spectrum by accommodating the radio spectrum dynamically to secondary users/unlicensed users without causing the interference. In cognitive radio, the spectrum opportunities have been checked for Space, Time and frequency dimensions but ‘Angle’ dimension has not been explored till now. In this paper we have investigated accuracy of various ‘Angle-of-Arrival (AoA)’ estimation algorithms: ESPRIT, MUSIC, Bartlett, and Capon for opportunistic secondary users’ network under AWGN and time varying fading channels. The improvement in performance of these algorithms has been observed as array elements, signal-to-noise ratio and samples increases. An ‘adaptive thresholding’ technique has been proposed to improve the performance of AoA algorithms. Thus by estimating an ‘Angle-of- Arrival’ of licensed users, the unlicensed users can be accommodated in the same geographical area into the same channel in the same frequency band at the same time by directing unlicensed users’ beam in different direction than the direction of licensed users. Thereby improving spectrum utilization.     

Defect Diagnosis Using a Current Ratio Based Quiescent Signal Analysis Model for Commercial Power Grids

Quiescent Signal Analysis (QSA) is a novel electrical-test-based diagnostic technique that uses I _DDQ measurements made at multiple chip supply pads as a means of locating shorting defects in the layout. The use of multiple supply pads reduces the adverse effects of leakage current by scaling the total leakage current over multiple measurements. In previous work, a resistance model for QSA was developed and demonstrated on a small circuit. In this paper, the weaknesses of the original QSA model are identified, in the context of a production power grid (PPG) and probe card model, and a new model is described. The new QSA algorithm is developed from the analysis of I _DDQ contour plots. A family of hyperbola curves is shown to be a good fit to the contour curves. The parameters to the hyperbola equations are derived with the help of inserted calibration transistors. Simulation experiments are used to demonstrate the prediction accuracy of the method on a PPG.