Studies in the photogalvanic effect in mixed reductants system for solar energy conversion and storage: Dextrose and Ethylenediaminetetraacetic acid-Azur A system

A mixture of two reductants (Dextrose and ethylenediamine tetraacetic acid) is used as a mixed reductants with Azur A as photosensitizer in the photogalvanic cell for solar energy conversion and storage with the aim to reduce the cost of construction for commercial viability. The photogeneration of photopotential and photocurrent were 778.0 mV and 55.0 μA, respectively, whereas maximum power of the cell was 42.79 μW. The observed power at power point of the cell was 10.87 μW and conversion efficiency was 0.1045%.The determined fill factor was 0.1942. The photogalvanic cell so developed can work for 115.0 min in dark where it was irradiated for 175.0 min. A mechanism for the photogeneration of electricity has also been proposed.     

Development of surface modification techniques for the covalent attachment of insulin-like growth factor-1 (IGF-1) on PECVD silica-coated titanium

Osseointegration is a complex process governed by the interaction of many cell types including blood cells (erythrocytes, platelets and leukocytes), phagocytic cells (macrophages) and bone cells (osteoblasts and osteoclasts) on or near the implant surface. The implant surface can be modified through a variety of methods in order to achieve control of some of these cellular interactions and consequently increase the degree of implant fixation with the surrounding bone tissue. In this investigation, titanium was coated with hydroxylated silica by plasma enhanced chemical vapour deposition (PECVD) to increase the surface hydrophilicity and generate reactive surface silanol groups. Subsequently, the silica-coated titanium surface was further modified through silanisation to generate surfaces bearing different reactive chemical functionalities consisting of aldehydes, epoxides and isocyanates, which can react with the amino groups of proteins and growth factors. 2,2,2-trifluoroethylamine (FEAM) was reacted on these surfaces to determine the coupling efficiency of the different surface chemical functionalities. The amino group of FEAM can react with an amino-reactive surface functional group to form a surface terminated with 3 fluorine atoms per FEAM molecule that can be detected by X-ray photoelectron spectroscopy. By analysing the techniques used for protein attachment with the FEAM model molecule, a successful method for isocyanate/amine coupling was found and later adapted for tethering IGF-1 molecules to the functionalised PECVD silica-coated titanium surface. Therefore, this simple method of preliminary testing protein reactivity may prove to be a cost effective strategy in the development of new biomaterial surfaces modified using protein bioconjugation methods.     

In situ grown titania composition for optimal performance and durability of Nafion® fuel cell membranes

Nafion® membranes were modified via in situ, catalyzed sol–gel reactions of titanium isopropoxide to form titania particles in the polar acid domains. FTIR spectroscopy showed successful intraparticle chemical bond formation with incomplete condensation of TiOH groups. Although such modification can lower membrane fuel cell performance, this study was aimed at reducing membrane degradation without significantly altering performance in the sense of material optimization. These incorporated particles did not change membrane equivalent weight and the water uptake was similar to that of the unmodified Nafion® membrane. Membrane dimensional stability, mechanical properties, and ability to withstand contractile stresses associated with humidity change at 80°C and 100% RH were improved. An open circuit voltage (OCV) accelerated degradation test showed the titania modification held voltage better than the unmodified membrane. Performance deterioration of Nafion® after the OCV test was much higher than that of the modified membrane and the fluoride emission of the latter was lower. The degraded Nafion® membrane failed when subjected to creep, whereas the modified membrane remained intact with significantly low deformation. This inorganic modification offers a simple way to enhance membrane durability by reducing both physical and chemical degradation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Sustained release of venlafaxine from venlafaxine–montmorillonite–polyvinylpyrrolidone composites

Due to shorter half life of venlafaxine, it is a prime requirement to develop a formulation which could extend the release of venlafaxine in the human body and also eliminate daily multiple dosage of venlafaxine. Montmorillonite (MMT) was used as sustained release carrier for venlafaxine by preparing venlafaxine–MMT by ion exchange. Venlafaxine–MMT was coated with polyvinylpyrrolidone to delay the release of venlafaxine. In vitro releases of venlafaxine from the various formulations were carried out in simulated gastric and intestinal fluids in controlled environment. 50% of venlafaxine was released by intestinal fluid within 5 h, > 95% within 48 h. Venlafaxine–MMT coated with PVP further decreased the release of venlafaxine.     

Rule induction for uncertain data

Data uncertainty are common in real-world applications and it can be caused by many factors such as imprecise measurements, network latency, outdated sources and sampling errors. When mining knowledge from these applications, data uncertainty need to be handled with caution. Otherwise, unreliable or even wrong mining results would be obtained. In this paper, we propose a rule induction algorithm, called uRule, to learn rules from uncertain data. The key problem in learning rules is to efficiently identify the optimal cut points from training data. For uncertain numerical data, we propose an optimization mechanism which merges adjacent bins that have equal classifying class distribution and prove its soundness. For the uncertain categorical data, we also propose a new method to select cut points based on possible world semantics. We then present the uRule algorithm in detail. Our experimental results show that the uRule algorithm can generate rules from uncertain numerical data with potentially higher accuracies, and the proposed optimization method is effective in the cut point selection for both certain and uncertain numerical data. Furthermore, uRule has quite stable performance when mining uncertain categorical data.     

Microwave assisted synthesis of ZnO:Cu nano-phosphors and their photoluminescence behaviour

During present investigations microwave assisted Cu doped ZnO nanoparticles were synthesized. Doped ZnO nanophosphors were characterized using X-ray diffraction analysis, transmission electron microscopy, steady state photoluminescence and time resolved laser induced photoluminescence spectroscopy. Optical parameters like Einstein’s spontaneous and stimulated coefficients, Trap depths, Decay constants, Oscillator Strengths, Integrated cross-section and dipole moments of ZnO nanostructures have been calculated and reported here.     

Radiation processing of minimally processed sprouts (dew gram and chick pea): effect on sensory,nutritional and microbiological quality

Sprouts have become an important part of the diet because of their nutritive value and low‐calorie content. The effect of radiation processing (1 and 2 kGy dose) on minimally processed dew gram and chick pea sprouts with respect to different quality parameters was studied over a storage period of 16 days at 8 °C. Radiation treatment and storage period did not have any significant effect on the sensory as well as nutritional qualities of irradiated dew gram and chick pea sprout. No significant change (P > 0.05) was observed in the colour and firmness of irradiated sprouts as compared to control samples. However, radiation processing resulted in significant reduction in aerobic plate counts (APC), coliform counts (CC), yeast and mould count (YMC) and staphylococci counts (SC). Radiation processing of dew gram and chick pea sprouts at 1 and 2 kGy extends the shelf life without affecting sensory and nutritional qualities.     

Green synthesis of biocompatible carbon dots using aqueous extract of Trapa bispinosa peel

We are reporting highly economical plant based method for the production of luminescent water soluble carbon dots (C-dot) using Indian water plant Trapa bispinosa peel extract without adding any external oxidizing agent at 90 °C. C-dots ranging from 5 to 10 nm were found in the solution with a prominent green fluorescence under UV-light (λ_ex = 365 nm). UV–vis spectra recorded at different time intervals (30–120 min) displayed signature absorption of C-dots between 400 and 600 nm. Fluorescence spectra of the dispersion after 120 min of synthesis exhibited characteristic emission peaks of C-dots when excited at 350, 400, 450 and 500 nm. C-dots were further analyzed using X-ray diffraction (XRD), Raman Spectroscopy and Thermo-Gravimetric Analysis (TGA). Structure of the C-dots was found to be turbostratic when studied using XRD. C-dots synthesized by our method were found to be exceptionally biocompatible against MDCK cells.     

Electromagnetic load calculation of the ITER machine using a single finite element model including narrow slits of the in-vessel components

We evaluate electromagnetic (EM) loads on the main systems of the ITER machine using a single finite element model. The 20° sector of the full ITER machine includes the main in-vessel components as well as the vacuum vessel. Narrow slits of the in-vessel components are effectively modeled by using the element splitting method without significant increase of computation memory and time as well as without sacrificing the accuracy. Furthermore, the halo current is taken into account at the same time together with the plasma current. To apply both currents concurrently, dedicated conversion codes are utilized to transfer the plasma simulation results by DINA to the electromagnetic analysis by ANSYS-EMAG used here. The electromagnetic loads on the ITER machine are calculated for various disruption scenarios. Investigation on the analysis results is made to find the worst plasma disruption case and the design-driving load component for each system as well as to compare load contribution from eddy and halo currents. The effect of the narrow slits on load reduction is also examined.     

Energy and economic analysis of traditional versus introduced crops cultivation in the mountains of the Indian Himalayas: A case study

This study analyzed the energy and economics associated with cultivation of traditional and introduced crops in the mountains of the Central Himalaya, India. The production cost in terms of energy for introduced crops such as tomato (Lycopersicon esculentum) and bell pepper (Capsicum annuum) cultivation was 90,358–320,516 MJ ha⁻¹ as compared to between 19,814 and 42,380 MJ ha⁻¹ for traditional crops within Himalayan agroecosystems. For the introduced crops, high energy and monetary input was associated with human labor, forest resources, chemical fertilizer and pesticides. However, energy threshold/projection for farmyard manure in traditional crop cultivation was 80–90% of the total energy cost, thus traditional crop cultivation was more efficient in energy and economics. During the study, the farm productivity of introduced crops cultivation declined with increasing years of cultivation. Consequently, the energy output from the system has been declining at the rate of −y20,598 to y20,748 MJ ha⁻¹ yr⁻¹ for tomato and y12,072 to y15,056 MJ ha⁻¹ yr⁻¹ for bell pepper under irrigated and rain-fed land use in the mountains, respectively. The comparative analysis on this paradigm shift indicates that more research is needed to support sustainable crop cultivation in the fragile Himalayan environment.