Pd–NPs@MMT–K10 Catalysis of Suzuki–Miyaura Cross-coupling Reaction: In Situ Generation and Ex Situ Use

Catalysis Letters - Due to high surface area and low swelling property, Montmorillonite–K10 (MMT–K10) has been gaining widespread applications in heterogeneous catalysis as a material...     

Paper mill sludge as a renewable substrate for the production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337

In the present study, pre-treated paper mill sludge (PMS) was evaluated extensively as a substrate for production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337. The PMS was subjected to three types of pre-treatment methods namely alkali, mechanical, and thermal treatment and was analyzed by SEM. The pre-treatment of PMS by alkali was observed to be more effective over the other pre-treatment methods. The alkali pre-treated sludge was then made to undergo fermentation, which showed the conventional process of acidogenesis followed by solventogenesis. The acetone, butanol, and ethanol concentration for 15% alkali pre-treated PMS was estimated to be maximum.     

A combined theoretical and experimental investigation of the valorization of mechanical and thermal properties of the fly ash-reinforced polypropylene hybrid composites

Journal of Materials Science - Fly ash (FA) particles were surface modified with cetyltrimethylammonium bromide (Ctab) and hybridized with graphene oxide (GO) and carboxymethyl cellulose (CMC)...     

A new analytical model for switching time of a perforated MEMS switch

In this paper, the design of a low-k meander based MEMS shunt capacitive switch with perforated beam meander has been presented. A closed form analytical model to calculate the switching time of designed structure is proposed. The model is based on modified Mejis and Fokkema’s capacitance model and linearization of non-linear electrostatic force on the switch beam. The model is utilized in evaluating the switching time for uniform as well as non-uniform serpentine meander designs, considering different values of actuation voltage and a wide variation of switching parameters. This work takes into account the beam perforation, fringing field and stiffness effect simultaneously altogether. The results obtained for both the meander designs under every design specifications has been found out to be less than or approximately equal to 100 µs. These model based results are then compared with 3D FEM simulated values. Comparative Analysis indicated that the model results and simulation results are in close agreement with each other.

     

Estimation of critical dimensions for a trapezoidal-shaped steel fin using hybrid differential evolution algorithm

This paper deals with the inverse prediction of parameters in a trapezoidal fin with temperature-dependent thermal conductivity and heat transfer coefficient. Three critical dimensions along with the relevant heat transfer coefficient at the fin base have been simultaneously predicted for satisfying a given temperature distribution on the surface of the trapezoidal fin. The inverse problem is solved by a hybrid differential evolution-nonlinear programming (DE-NLP) optimization method. For a given fin material which is considered to be stainless steel, it is found from the present study that many feasible dimensions exist which satisfy a given temperature distribution, thereby providing flexibility in selecting any dimensions from the available alternatives by appropriately regulating the base heat transfer coefficient. A very good estimation of the unknown parameters has been obtained even for temperature distribution involving random measurement errors which is confirmed by the comparisons of the reconstructed distributions. It is concluded that for a given fin material, the hybrid DE-NLP algorithm satisfactorily estimates feasible dimensions of a trapezoidal fin even with random measurement error of 11 %.

     

Implications of silver nanoparticle induced cell apoptosis for in vitro gene therapy

The impact of manufactured nanomaterials on human health and the environment is a major concern for commercial use of nanotechnology based products. A judicious choice of selective usage, lower nanomaterial concentration and use in combination with conventional therapeutic materials may provide the best solution. For example, silver nanoparticles (Ag NPs) are known to be bactericidal and also cytotoxic to mammalian cells. Herein, we investigate the molecular mechanism of Ag NP mediated cytotoxicity in both cancer and non-cancer cells and find that optimum particle concentration leads to programmed cell death in vitro. Also, the benefit of the cytotoxic effects of Ag NPs was tested for therapeutic use in conjunction with conventional gene therapy. The synergistic effect of Ag NPs on the uracil phosphoribosyltransferase expression system sensitized the cells more towards treatment with the drug 5-fluorouracil. Induction of the apoptotic pathway makes Ag NPs a representative of a new chemosensitization strategy for future application in gene therapy.     

Development of Apparels from Silk Waste and Pineapple Leaf Fiber

The degummed mulberry silk waste and eri silk waste were blended with degummed and bleached pineapple leaf fibers (PALF) at fiber stage in different proportions, and spun into yarn in a jute spinning system. The 90-tex blended yarn thus developed was analyzed for different physico-mechanical properties. Properties of fabric developed in a traditional handloom using 2/40-s cotton as warp and blended yarn as weft were also analyzed. The quality parameters, viz., tensile property, crease recovery, fabric cover, stiffness, drape, and thickness of the developed fabric, met essential apparel requirements. A comparative subjective evaluation of the fabric quality, viz., aesthetic appearance, luster, and texture, was made with the help of a group of people from different age, educational, and occupational background to examine its marketability; all respondents felt that appearance of PALF with silk waste was excellent. Texture and luster were found to be from medium to moderate. About 95% of respondents felt that fabric was crispy.     

Chemical characterisation of CTC black tea of northeast India: correlation of quality parameters with tea tasters' evaluation

BACKGROUND: Consumers have different regional perceptions of tea quality. Objective evaluation based on biochemical data for different regions has been needed for a long time. Biochemical factors regulating this variation would help to remove regional disparities. This study was undertaken on CTC (crust, tear and curl) black tea to generate the biochemical data responsible for quality along with tea tasters' evaluation of three geographical regions of northeast India and to determine the reason for the variation. RESULTS: Brahmaputra valley teas had highest theaflavin (TF), thearubigin (TR), brightness (BR) and total colour (TC) and low crude fibre content (CFC) and total polyphenol (TPP). Brahmaputra valley and Dooars region teas showed high total soluble solid (TSS). Barak valley teas had highest CFC and low TSS, caffeine (CA), TF, TR and TC. Dooars region teas had high CA and TPP and low BR. Dooars region and Barak valley teas contained higher levels of residual catechin than Brahmaputra valley teas. CONCLUSION: Overall quality as evaluated by tea tasters was found to be highest for Brahmaputra valley teas followed by Dooars region and Barak valley teas. This high evaluation can be attributed to higher levels of TF, TR, BR and TSS. Barak valley and Dooars region teas contained high residual catechin, indicating limitation in oxidation during processing. Copyright © 2009 Society of Chemical Industry     

High band gap nanocrystallite embedded amorphous silicon prepared by hotwire chemical vapour deposition

Hydrogenated silicon films ranging from pure amorphous to biphasic silicon i.e., nanocrystallites embedded amorphous silicon are prepared in an indigenously fabricated hot wire chemical vapor deposition chamber by varying the substrate temperature (T_s) and process pressure (PP). The deposition rates are found to be about 2.5-14 Å/s, which is very much appreciated for the fabrication of cost effective devices. While the films deposited at low T_s are amorphous in nature, those deposited at T_s ≥ 200 °C contain nanocrystallites embedded in the amorphous network. These mixed phase films show high crystalline fraction of 50-56%. All the films deposited at 250 °C, by varying PP, are nanocrystallite embedded with crystalline fraction 60-75%. The optical band gaps of the films (2.0-2.37 eV) are high compared to the regular films, whereas the hydrogen content remains in the reported range of 2.5-5 at.%. We attribute the high optical band gap to the improved order as well as the presence of low density amorphous tissues surrounding the grain boundary regions. The ease of depositing films with tunable band gap is useful for fabrication of tandem solar cells.     

Effect of Ag doping on the electrical properties of thermally deposited CdS–La2O3 TFTs

This paper describes a new approach for repairing memories. Repair is implemented by deletion of either rows and/or columns on which faulty cells lie. These devices are commonly referred to as redundant memories, because redundant columns and rows are added. A new repair technique and an algorithm are proposed. The algorithm is based on a fault-counting technique and on a reduced-covering approach. The innovative feature is that reduced covering permits an heuristic, but efficient, criterion to be included in the selection of the rows and/or columns to be deleted. This retains independence of the repair process on the distribution of faulty cells in memory, while allowing a good repairability/ unrepairability detection. The main benefits that result by using the proposed repair algorithm are a reduction in execution time to determine the repair-solution for the device under test and its suitability for implementation in a defect analysis system. Illustrative examples and theoretical results are provided to substantiate the validity of the proposed repair technique