000888   Sarkar M;Dana K;Ghatak S;Banerjee A (Clay & Traditional Ceramics Div, Central Glass and Ceramic Research Institute, Kolkata-700 032, Email: kdana@cgri.res.in) : Polypropylene-clay composite prepared from Indian bentonite. Bull Mater Sci 2008, 31(1), 23-8.

A set of experimental polypropylene (PP) clay composites containing pristine bentonite clay of Indian origin has been prepared and then characterized. The polymer clay composites are processed by solution mixing of polypropylene with bentonite clay using a solvent xylene and high speed electric stirrer at a temperature around 130°C and then by compression molding at 170°C. The mechanical properties of PP-clay composites like tensile strength, hardness and impact resistance have been investigated. Microstructural studies were carried out using scanning electron microscope and transmission electron microscope and the thermal properties were studied using differential scanning calorimeter. Mechanical properties of the prepared composites showed highest reinforcing and toughening effects of the clay filler at a loading of only 5 mass % in PP matrix. Tensile strength was observed to be highest in case of 5 mass % of clay loading and it was more than 14% of that of the neat PP, while toughness increased by more than 80%. Bentonite clay-PP composite (5 mass %) also showed 60% increase in impact energy value. However, no significant change was observed in case of hardness and tensile modulus. Higher percentages of bentonite clay did not further improve the properties with respect to pristine polypropylene. The study of the microstructure of the prepared polymer layered silicate clay composites showed a mixed morphology with multiple stacks of clay layers and tactoids of different thicknesses.

10 illus, 2 tables, 14 ref

000887   Saikia B J;Parthasarathy G;Sarmah N C;Baruah G D (NO, National Geophysical Research Institute, Uppal Road, Hyderabad-500 007, Email: gpsarathy@ngri.res.in) : Fourier-transform infrared spectroscopic characterization of naturally occurring glassy fulgurites. Bull Mater Sci 2008, 31(2), 155-8.

Reports for the first time the spectroscopic characterization of natural fulgurites of Garua-mukh. On April 22, 2005 at 04 : 00 local time, large amounts of black-brown colour of colloidal solution came out from below the earth's surface at Garuamukh near Nagaon town (latitude 26°20'39"N, longitude 92°41'39"E, Assam, India) with fire and smoke. This colloidal solution got transformed into fulgurites, glassy material, within a few hours. The characterization of the fulgurites by Fourier transform infrared (FTIR) absorption, X-ray diffraction and X-ray fluorescence methods. The amorphous nature of the substance has been confirmed by Fourier transform infrared spectra of the fulgurites, which exhibit prominent absorption band in the region 400-1200 cm^-1, the basic component of amorphous silica. The present study might have significant implications in understanding the thermodynamic properties of naturally occurring glasses, which are formed by shock metamorphism.

3 illus, 2 table, 14 ref

000886   Sabharwal S;Palit S;Tokas R B;Poswal A K; Sangeeta (Crystal Technology Laboratory, TPPED, Bhabha Atomic Research Centre, Mumbai-400 085, Email: sangita@barc.gov.in) : Electroless deposition, post annealing and characterization of nickel films on silicon. Bull Mater Sci 2008, 31(5), 729-36.

Electroless deposition of nickel (EN) films on n-type silicon has been investigated under different process conditions. The interface between the film and substrate has been characterized for electrical properties by probing the contact resistances. X-ray diffraction and atomic force microscopy have been performed to obtain information about the structural and morphological details of the films. As a comparative study, nickel films have also been sputter deposited on silicon substrates. An as-deposited electroless film is observed to form non-ohmic contact while in a sputtered film prepared without the application of substrate heating, the formation of metal-insulating-semiconductor type junction is seen.

11 illus, 2 tables, 15 ref

000885   Rajasekaran R;Alagar M (Chemical Engineering Dep, Anna Univ, Chennai-600 025, Email: mkalagar@yahoo.com) : Mechanical properties of polyethersulfone modified epoxy/3,3'-bis (maleimidophenyl)phenylphosphine oxide (BMI) intercrosslinked matrices. Bull Mater Sci 2008, 31(6), 853-8.

Novel intercrosslinked networks of polyethersulfone modified epoxy-3,3'-&w(maleimidophenyl) phenylphosphine oxide matrix systems are developed. The polyethersulfone modification of epoxy resin is carried out by using tetramethyl ammonium hydroxide (TMAII) as a catalyst. The polyethersulfone modified epoxy systems are further modified with 4-12% 3,3'-œw(maIeimidophenyl) phenylphosphine oxide and cured by using diaminodiphenylmethane. Tensile, flexural, impact properties and dynamic mechanical analysis (DMA) are carried out to assess the mechanical behaviour of the prepared neat resin castings. Mechanical studies indicate that the introduction of polyethersulfone into these epoxy resins improves the toughness without any reduction in the stress-strain values. But, the incorporation of bismaleimide (BMI) into the epoxy resin improves the stress-strain properties with a lowering of the toughness. The introduction of both polyethersulfone and bismaleimide into the epoxy resin influences the mechanical properties according to their content percentages.

3 illus, 1 table, 16 ref

000884   Raidongia K;Eswaramoorthy M (Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560 064, Email: eswar@jncasr.ac.in) : Synthesis and characterization of metal oxide nanorod brushes. Bull Mater Sci 2008, 31(1), 87-92.

Nanorod brushes of α-Al₂O₃, MoO₃ and ZnO have been synthesized using amorphous carbon nanotube (a-CNT) brushes as the starting material. The brushes of α-Al₂O₃ and MoO₃ are made up of single crystalline nanorods. In the case of ZnO brushes, the hanorod bristles are made by the fusion of 15-25 nm size nanoparticles and are porous in nature. Metal oxide nanorod brushes thus obtained have been characterized by XRD, FESEM, TEM and Raman spectroscopy. Single crystalline ruby nanorods were obtained by introducing chromium ions during the synthesis of alumina rods.

6 illus, 22 ref

000883   Premalatha M;Shanmuga Priya S; Sivaramakrishnan V (Centre for Energy & Environmental Science and Technology (CEESAT), National Institute of Technology, Tiruchirappalli-620 015, Email: manic_prem@yahoo.co.in) : Efficient cogeneration scheme for sugar industry. J scient ind Res 2008, 67(3), 239-42.

A case study on sugar industry and economics is worked out for advanced cogeneration power system. By replacing low efficiency mill turbines with hydraulic drives and DC motors, cogeneration power increases in sugar mill to operate at high efficiency (65-70%). This replacement can aid increase of power to grid, resulting in additional revenue for sugar plant.

2 illus, 3 tables, 10 ref

000882   Patil S D;Jali V M;Anavekar R V (Physics Dep, Gulbarga Univ, Gulbarga-585 106, Email: vmjali@rediffmail.com) : Synthesis and structural studies of Na₂O-ZnO-ZnF₂-B₂O₃ oxyfluoride glasses. Bull Mater Sci 2008, 31(4), 631-4.

Describes the synthesis and spectroscopic studies of the glass system, 20Na₂O-(20-x) ZnO-xZnF₂-60B₂O₃ (x - 0, 5, 10, 15, 20), prepared by melt quenching method. The analyses of DSC and XRD did not show the crystallinity of the glass sample. ¹¹B MAS-NMR shows the presence of sharp peak around -14ppm. From the IR studies, the broadening of the peak around 1200-1400 and 800-1100 cm^-1 shows the presence of mixed linkages like B-O-B, B-O-Zn in the network.

5 illus, 17 ref

000881   Parekh B B;Vyas P M;Vasant S R;Joshi M J (Physics Dep, Saurashtra Univ, Rajkot-360 005, Email: mshilp24@rediffmail.com) : Thermal, FT-IR and dielectric studies of gel grown sodium oxalate single crystals. Bull Mater Sci 2008, 31(2), 143-7.

Oxalic acid metabolism is important in humans, animals and plants. The effect of oxalic acid sodium salt is widely studied in living body. The growth of sodium oxalate single crystals by gel growth is reported, which can be used to mimic the growth of crystals in vivo. The grown single crystals are colourless, transparent and prismatic. The crystals have been characterized by thermogravimetric analysis, FT-IR spectroscopy and dielectric response at various frequencies of applied field. The crystals become anhydrous at 129.3°C. Coats and Redfern relation is applied to evaluate the kinetic and thermodynamic parameters of dehydration. The dielectric study suggests very less variation of dielectric constant with frequency of applied field in the range of 1 kHz-1 MHz. The nature of variation of imaginary part of complex permittivity, dielectric loss and a.c. resistivity with applied frequency has been reported.

8 illus, 2 tables, 27 ref

000880   Pandey K;Dwivedi M M (National Centre of Experimental Mineralogy and Petrology, Allahabad Univ, Allahabad-211 002, Email: kp542831@gmail.com) : Natural and fancy diamonds: synthesis and characterization techniques. Proc Natn Acad Sci India-Sect A 2008, 78(Pt 3), 231-6.

Synthesized diamond from graphite using multi-anvil high pressure apparatus at 60 kilobar pressure. The coloration of the natural diamond was carried out by the irradiation process followed by high pressure - high temperature method. The natural, synthetic and colored diamonds were studied by various experimental tools like XRD, IR and optical spectra.

4 illus, 4 tables, 12 ref

000879   Pan W;Zou H (Institute of Materials and Chemical Engineering, Zhongyuan Univ of Technology, Zhengzhou 450007, P.R. China, Email: panwei@zzti.edu.cn) : Characterization of PAN/ATO nanocomposites prepared by solution blending. Bull Mater Sci 2008, 31(5), 807-11.

Conducting nanocomposites of polyacrylonitrile (PAN) and antimony-doped tin oxide (ATO) were prepared by solution blending. Electrical properties of the nanocomposites were characterized by means of electrical conductivity measurements and the phase structures were investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analyses (TGA) and dynamical mechanical analysis (DMA). This study unveiled a remarkable, interpenetrating network of chainlike nano-ATO within the PAN matrix, consistent with the existence of connected conducting paths at content as low as 4 wt% of the nano-ATO. The storage modulus of the nanocomposites increased with increasing content of ATO, due to formation of immobilized layer between polymer and filler. The interactions between ATO and PAN molecules resulted in high tan δ for the PAN/ATO nanocomposites. Thermal stability of the nanocomposites was found remarkably enhanced by the incorporation of nano-ATO.

6 illus, 18 ref

000878   Nidhin M;Indumathy R;Sreeram K J;Nair B U (Chemical Laboratory, Central Leather Research Institute, Chennai-600 020, Email: kjsreeram@clri.info) : Synthesis of iron oxide nanoparticles of narrow size distribution on polysaccharide templates. Bull Mater Sci 2008, 31(1), 93-6.

Reports the preparation of nanoparticles of iron oxide in the presence of polysaccharide templates. Interaction hetvveen iron (II) sulfate and template has been carried out in aqueous phase, followed by the selective and controlled removal of the template to achieve narrow distribution of particle size. Particles of iron oxide obtained have been characterized for their stability in solvent media, size, size distribution and crystallinity and found that when the negative value of the zeta potential increases, particle size decreases. A narrow particle size distribution with D₁₀₀ = 275 nm was obtained with chitosan and starch templates. SEM measurements further confirm the particle size measurement. Diffuse reflectance UV-vis spectra values show that the template is completely removed from the final iron oxide particles and powder XRD measurements show that the peaks of the diffractogram are in agreement with the theoretical data of hematite. The salient observations of our study shows that there occurs a direct correlation between zeta potential, polydispersity index, bandgap energy and particle size. The crystallite size of the particles was found to be 30-35 nm. A large negative zeta potential was found to be advantageous for achieving lower particle sizes, owing to the particles remaining discrete without agglomeration.

3 illus, 1 table, 11 ref

000877   Narayanan T N;Sakthi Kumar D;Yoshida Y; Anantharaman M R (Physics Dep, Cochin Univ of Science and Technology, Cochin-682 022, Email: mraiyer@gmail.com) : Strain induced anomalous red shift in mesoscopic iron oxide prepared by a novel technique. Bull Mater Sci 2008, 31(5), 759-66.

Nano magnetic oxides are promising candidates for high density magnetic storage and other applications. Nonspherical mesoscopic iron oxide particles are also candidate materials for studying the shape, size and strain induced modifications of various physical properties viz. optical, magnetic and structural. Spherical and nonspherical iron oxides having an aspect ratio, ~2, are synthesized by employing starch and ethylene glycol and starch and water, respectively by a novel technique. Their optical, structural, thermal and magnetic properties are evaluated. A red shift of 0.24 eV is observed in the case of nonspherical particles when compared to spherical ones. The red shift is attributed to strain induced changes in internal pressure inside the elongated iron oxide particles. Pressure induced effects are due to the increased overlap of wave functions. Magnetic measurements reveal that particles are superparamagnetic. The marked increase in coercivity in the case of elongated particles is a clear evidence for shape induced anisotropy. The decreased specific saturation magnetization of the samples is explained on the basis of weight percentage of starch, a nonmagnetic component and is verified by TGA and FTIR studies. This technique can be modified for tailoring the aspect ratio and these particles are promising candidates for drug delivery and contrast enhancement agents in magnetic resonance imaging.

11 illus, 21 ref

000876   Muralidhara H B;Arthoba Naik Y (PG Studies and Research in Chemistry Dep, School of Chemical Sciences, Kuvempu Univ, Shankaraghatta-577 451, Email: drarthoba@yahoo.co.in) : Nanocrystalline zinc coating. Bull Mater Sci 2008, 31(4), 585-91.

Nano zinc coatings were deposited on mild steel by electrodeposition. The effect of additive on the morphology of crystal size on zinc deposit surface and corrosion properties were investigated. Corrosion tests were performed for dull zinc deposits and bright zinc deposits in aqueous NaCl solution (3.5 wt.%) using electrochemical measurements. Results showed that addition of additive in the deposition process of zinc significantly increased the corrosion resistance. The surface morphology of the zinc deposits was studied by scanning electron microscopy (SEM). The preferred orientation and average size of the zinc electrodeposited particles were obtained by X-ray diffraction analysis. The particles size was also characterized by TEM analysis.

10 illus, 3 tables, 22 ref

000875   Mohapatra S R;Thakur A K;Choudhary R N P (Physics & Meteorology Dep, Indian Institute of Technology, Kharagpur-721 302, Email: akt@phy.iitkgp.ernet.in) : Studies on dielectric properties of a conducting polymer nanocomposite system. Indian J Engng Mater Sci 2008, 15(4), 347-51.

Dielectric analysis of ion conducting solid polymer nanocomposite has been investigated as a function of temperature and frequency. Effect of clay concentration in changing the dielectric relaxation behaviour of polymer salt complex film is clearly visible, observed in terms of changes in polymer chain relaxation and dipolar contribution due to ion pairs. An enhancement in relative permittivity by 2 orders of magnitude has been recorded at room temperature in nanocomposite films controlled predominantly by clay concentration. Almost similar behaviour has been observed after crystalline to amorphous phase transition temperature at T ≥70°C for both polymer salt complex and nanocomposite films irrespective of clay concentration. A lowering of relaxation time, attributed to relaxing dipoles, with clay concentration suggests faster ion dynamics in nanocompositc films.

4 illus, 5 ref

000874   Mizutani N;Iwasaki T;Watano S;Yanagida T; Tanaka H;Kawai T (Chemical Engineering Dep, Osaka Prefecture Univ, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan, Email: iwasaki@chemeng.osakafu-u.ac.jp) : Effect of ferrous/ferric ions molar ratio on reaction mechanism for hydrothermal synthesis of magnetite nanoparticles. Bull Mater Sci 2008, 31(5), 713-17.

Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio.

5 illus, 15 ref

000873   Mishra P R;Dash D;Mishra B K (Entomology Dep, College of Agriculture, Orissa Univ of Agriculture & Technology, Bhubaneswar-751 003) : Effect of different storage receptacles on the oviposition, development and quantitative loss by the bruchid, Caryedon serratus (Olivier) in stored groundnut. Envir Ecol 2008, 26(4B), 2181-2.

Evaluation of different types of bags as receptacles on the oviposition and development of C. serratus on pods of groundnut revealed that gunny bags impregnated with deltamethrin (0.0125%) and alphamethrin (0.0125%) and polythene-coaltar coated gunny bags afforded complete protection up to six months, whereas polythene bags, gunny bags and polythene coated gunny bags were found to provide comparatively less protection recording more amount of per cent weight loss in pods.

^ssc1 table, 4 ref

000872   Milintawisamai N;Niamsanit S;Ngasan C; Maungmontri R;Buttapeng W;Kotrsri R;Pliansinchai A;Weerathaworn P (Biochemistry Dep, Faculty of Science, Khon Kaen Univ, Khon Kaen 4002, Thailand, Email: nipmil@kku.ac.in) : Efficacy of dimethyl benzyl ammonium chloride and microbial contamination studies in a modern sugarcane milling unit in Thailand. Sugar Tech 2009, 11(2), 208-12.

The modern milling process at Mitr Phuveing Sugar factory takes less than 10 min from cane stalk to mixed juice stage before the liming process. However, the microorganisms still affect sugar yield in the factory. The efficacy of dimethyl benzyl ammonium chloride (DBAC) and microbial contamination in the sugar cane juice from milling process were studied. The inhibitory effect of DBAC on the total microorganism, yeast and mold, and lactic acid bacteria in sugar cane juice was assessed aerobically by shaking at 45°C for 10 minutes. The concentration of sucrose and dextran were determined by High Performance Liquid Chromatography and Haze method of ICUMSA, respectively. The results showed that 2 and 6 ppm of DBAC cannot inhibit all kinds of microorganism within 10 minutes. The microbial population and dextran did not increase in sugar cane juice within 10 minutes. However, sucrose losses were noticed because of microbial utilization. Microbial population in the first, third and mixed juice in the milling process were monitored before and after sanitation by hot water and biocide application. The results showed that all kinds of microbial population varied with raw material. The microbial contaminations in some samples of sugar juice from the milling process were selected from plate count agar, malt extract agar and MRS agar medium containing 10% sucrose and identified by physiological and biochemical tests. The microbial contaminations found were mainly yeast: Saccharomyces cerevisiae, Candida guilliermondii and Candida tropicalis, and bacteria: Klebsiella pneumoniae, Lactobacillus ferment urn, Enterobacter agglomerans and E. cloacae.

5 illus, 1 table, 14 ref

000871   Maurya D;Singh D P;Agrawal D C;Mohapatra Y N (Materials Science Programme, Physics Dep, Indian Institute of Technology, Kanpur-208 016, Email: agrwald@iitk.ac.in) : Preparation of high dielectric constant thin films of CaCu₃Ti₄O₁₂ by sol-gel. Bull Mater Sci 2008, 31(1), 55-9.

Preparation of sol-gel derived CaCu₃Ti₄O₁₂ (CCTO) thin films using two different sols and their characterization including their dielectric response are reported. The properties of CCTO films depend heavily on solvents used to prepare the sols. Dielectric constant as high as ~900 at 100 kHz could be obtained when acetic acid was used to prepare the sol; in contrast, use of hexanoic acid in the sol yielded films with a much lower dielectric constant. The variation in grain and grain boundary conductivities with temperature has been measured. Activation energies of 0.08 eV and 0.68 eV have been found for grain and grain boundary conduction, respectively.

7 illus, 19 ref

000870   Mathur A K;Majumder C B (Chemical Engineering Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: cbmajumder@yahoo.com) : Biofiltration of benzene emissions: biofilter response to variations in the pollutants inlet concentration and gas flow rate. J scient ind Res 2008, 67(3), 243-8.

To examine biofilter response with varying loading rate, a laboratory-based biofilter, packed with mixture of compost, sugar cane bagasse and granulated active carbon (GAC), was used for treating benzene. At influent benzene loadings (< 40 g m^-3h^-1), nearly 100% removal could be achieved. Maximum elimination capacity of biofilter was 83.65 g m^-3h^-1 at inlet benzene load of 69 g m^-3h^-1. Using Wani's method of macrokinetic determination, maximum removal rate (μ_max ) was calculated as 0.017 g m^-3s^-1, and saturation constant (K_s) of benzene value as 0.0226 g m^-3. Increase in CO₂ production with elimination capacity suggested that removal of benzene was due to microorganism and good due to the performance of biofilter. The mixture of packing material of bagasse, compost and GAC appears to be an efficient packing material for low to medium loading rate.

6 illus, 19 ref

000869   Mahapatra P K;Kumar A;Singh M;Grewal N S; Pandey L;Singla M L (Material Research Div, Central Scientific Instruments Organisation, Sector 30C, Chandigarh-160 030, Email: prasant22@yahoo.com) : Microcontroller based portable instrument for determination of nickel in edible oils. J scient ind Res 2008, 67(2), 132-5.

A microcontroller (μC) 89C5JRD2BN based portable instrument has been developed for determination of nickel (Ni) concentration in edible oil using dimethylglyoxime method. An LED has been used as a light source with peak wavelength at 450 nm. Silicon photodiode is used as a detector having peak spectral response at 550 nm.

2 illus, 2 tables, 8 ref

000868   Liu W;Yunzhu M A;Huang B (State Key Laboratory for Powder Metallurgy, Central South Univ, Changsha 410083, P.R. China, Email: zhuzipm@mail.csu.edu.cn) : Influence of minor elements additions on microstructure and properties of 93W-4.9Ni-2.1Fe alloys. Bull Mater Sci 2008, 31(1), 1-6.

Effects of elements rhenium and chromium additions on properties and microstructure of 93W-4.9Ni.2.1Fe alloys were investigated. Optical microscope (OM), scanning electron microscope (SEM) and EDAX energy spectrometer were used to characterize the microstructure and compositions of the alloys, respectively. The tensile strength and elongation of alloys were evaluated using the quasi-static tensile testing machine, and the relative densities of the alloys were evaluated using the Archimedes water immersion method. The experimental results indicated that when elements Re and Cr were in the range of 0-1-0 wt.%, relative density, elongation, tensile strength of 93W-4.9Ni-2.1Fe alloys varied from 99.4%, 26.4%, 997.2 MPa without Re additions to 99.5%, 8.6%, 1161-2 MPa with 1.0 wt.% Re addition, respectively. Rhenium generated solid-solution strengthening, grain refinement, reducing ductile tearing and increasing transcrystalline fracture, which resulted in the ductility reduction and the strength increase of the heavy alloys. With the increase of Cr content from 0.1.0 wt.%, the tensile strength, relative density and elongation of 93W.Ni.Fe alloy reduced from 997.2 MPa, 99.3%, 15% to 844.4 MPa, 95.2%, 5.7%, respectively. Element Cr formed inter-phases with elements W, Ni, Fe and O and gathered along the interface of the alloys, which induced interfacial cohesion and resulted in lower mechanical properties of 93W-Ni-Fe alloys.

7 illus, 13 ref

000867   Liu B;Jia D;Rao J;Meng Q;Shao Y (Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001, China, Email: dcjia@hit.edu.cn) : Novel method for preparation of hollow and solid carbon spheres. Bull Mater Sci 2008, 31(5), 771-4.

Hollow and solid carbon spheres were prepared by the reaction of ferrocene and ammonium carbonate in a sealed quartz tube at 500°C. The morphology and microstructure of the product were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The carbon spheres are amorphous and their diameters range from 0.8.2.8 μm. The shell thickness of the hollow carbon spheres is not uniform and ranges from 100-180 nm. It is suggested that ammonium carbonate is crucial for the formation of carbon spheres and its amount also influences the morphology of the product. The method may be suitable for large scale preparation of carbon spheres.

5 illus, 14 ref

000866   Li Z;Wu C;Liu Y;Liu T;Jiao Z;Wu M (Institute of Nanochemistry and Nanobiology, School of Environmental an, Shanghai Univ, Shanghai 200444, P.R. China, Email: mhwu@staff.edu.cn) : Preparation of PbSe nanoparticles by electron beam irradiation method. Bull Mater Sci 2008, 31(6), 825-9.

A novel method has been developed by electron beam irradiation to prepare PbSe nanoparticles. 2 MeV 10mA GJ-2-II electronic accelerator was used as radiation source. Nanocrystalline PbSe was prepared rapidly at room temperature under atmospheric pressure without any kind of toxic reagents. The structure and morphology of prepared PbSe nanoparticles were analysed by X-ray diffraction, transmission electron microscope and atomic force microscope. The results indicated that the obtained materials were cubic nanocrystalline PbSe with an average grain size of 30 nm. The optical properties of prepared PbSe nanocrys-talline were characterized by using photoluminescence spectroscopy. The possible mechanism of the PbSe grain growth by electron beam irradiation method is proposed.

6 illus, 18 ref

000865   Kunte G V;Shivashankar S A;Umarji A M (Materials Research Centre, Indian Institute of Science, Bangalore-560 012, Email: umarji@mrc.iisc.ernet.in) : Humidity sensing characteristics of Hydrotungstite thin films. Bull Mater Sci 2008, 31(6), 835-9.

Thin films of the hydrated phase of tungsten oxide, hydrotungstite (H₂WO₄.H₂O), have been grown on glass substrates using a dip-coating technique. The b-axis oriented films have been characterized by X-ray diffraction and scanning electron microscopy. The electrical conductivity of the films is observed to vary with humidity and selectively show high sensitivity to moisture at room temperature. In order to understand the mechanism of sensing, the films were examined by X-ray diffraction at elevated temperatures and in controlled atmospheres. Based on these observations and on conductivity measurements, a novel sensing mechanism based on protonic conduction within the surface layers adsorbed onto the hydrotungstite film is proposed.

5 illus, 1 table, 18 ref

000864   Kumari K;Kundu P P (Chemical Technology Dep, Sant Longowal Institute of Engineering and Technology, Longowal-148 106, Email: ppk923@yahoo.com) : Studies on in vitro release of CPM from semi-interpenetrating polymer network (IPN) composed of chitosan and glutamic acid. Bull Mater Sci 2008, 31(2), 159-67.

Interpenetrating polymer network (IPN) beads consisting of chitosan-glutamic acid were prepared for in vitro study of controlled release of chlorpheniramine maleate (CPM). A viscous solution of chitosan-glutamic acid was prepared in 2% acetic acid solution, extruded as droplets through a syringe to alkali-methanol solution and the precipitated beads were crosslinked using glutaraldehyde solution. Swelling and drug release studies were carried out. Transport of release medium through the semi-IPN depended upon its pll and extent of crosslinking. The structural and morphological studies of beads were carried out by using a scanning electron microscope (SEM). The larger surface area of beads as well as their ease of handling makes them ideal agents of controlled release.

5 illus, 3 tables, 14 ref

000863   Kaya Y;Gonder Z B;Vergili I;Barlas H (NO, Istanbul Univ, Faculty of Engineering, Avcilar, Istanbul 34320, Turkey, Email: y_kaya@istanbul.edu.tr) : Removal of cetyltrimethylammonium bromide and sodium dodecylether sulfate by granular activated carbon. J scient ind Res 2008, 67(3), 249-53.

Adsorption isotherms of sodium dodecylether sulfate (SLES) and cetyltrimethylammonium bromide (CTAB) onto granular activated carbon (GAC) at 25°C (aqueous solution) were experimentally determined by batch tests with respect to contact time, adsorbent amount and initial surfactant concentration. Close agreement of experimental data with Langmuir equilibrium model was observed. In Langmuir model, adsorptive capacity of CTAB was higher than that of SLES (Q° = 70.423 and 52.08 mgg^-1, respectively). L type isotherms were obtained that showed no strong competition among solvent molecules and surfactant molecules for the adsorption sites.

7 illus, 30 ref

000862   Kameda T;Yoshioka T;Yabuuchi F;Uchida M; Okowaki A (Applied Chemistry Dep, Graduate School of Engineering, Tohoku Univ, Aoba 07, Aoba-ku, Sendai 980-8579, Japan, Email: kameda@env.che.tohoku.ac.jp) : Effects of pH and concentration on ability of Cl<. Bull Mater Sci 2008, 31(4), 625-9.

This study, confirmed that the characteristics of anion intercalation into the interlayer of a hydrotalcite-like compound (HT) during synthesis are similar to those of the anion-exchange reaction of HTs as well as the reconstruction reaction of HTs from Mg-Al oxide. It is demonstrated that (i) Cl^-, which has a higher charge density than NO^-₃, more easily reacted with Mg and Al species to form HT structure, resulting in greater intercalation of Cl^- into the HT interlayer; and (ii) for HTs with lower Mg : Al molar ratios, OH^-, which has a higher charge density than Cl^- and NO^-₃, was more likely to interact with Mg and Al species td'form IIT structure, blocking the intercalation of Cl^- and NO₃^-. Furthermore, we showed that high concentrations of CP and NO₃^- in solution regulated their intercalation into the HT interlayer. The high activity of Cl^- and NO₃^- in solution would facilitate the anions' reactions with Mg and Al species to form HTs, resulting in a high degree of anion intercalation into the interlayer of HTs.

5 illus, 16 ref

000861   Kalampounias A G (Chemical Engineering Dep, Patras Univ, P.O. Box 1414, GR 26504, Patras, Greece, Email: angelos@chemeng.upatras.gr) : Low-frequency raman scattering in alkali tellurite glasses. Bull Mater Sci 2008, 31(5), 781-5.

Raman scattering has been employed to study the alkali-cation size dependence and the polarization characteristics of the low-frequency modes for the glass-forming tellurite mixtures, 0-1M2O-0-9TeO2 (M = Na, K, Rb and Cs). The analysis has shown that the Raman coupling coefficient alters by varying the type of the alkali cation. The addition of alkali modifier in the tellurite network leads to the conversion of the TeO₄ units to TeO₃ units with a varying number of non-bridging oxygen atoms. Emphasis has also been given to the low-frequency modes and particular points related to the low-frequency Raman phenomenology are discussed in view of the experimental findings.

5 illus, 12 ref

000860   Kakirde A;Sinha B;Sinha S N (Electronics and Computer Engineering Dep, Indian Institute a Technology, Roorkee-247 667, Email: sn_sinha@ieee.org) : Development and characterization of nickel-zinc spinel ferrite for microwave absorption at 2.4 GHz. Bull Mater Sci 2008, 31(5), 767-70.

Deals with the development and characterization of nickel-zinc spinel ferrite (Ni_{(1-δ) ZnδFe2O4) for microwave absorption at 2.4 GHz (ISM band). The ferrite powder was prepared by dry attrition and sintering process. Complex permittivity and permeability of the prepared sample have been determined by measuring its scattering parameters with the help of a vector network analyser. The measured parameters have been used to determine its wave absorption properties over a frequency range 2.1.2.6 GHz.}

7 illus, 1 table, 5 ref

000859   Jimenez E R (Quimica Fisica Div, Centro de Ingenieria Genetica y, Biotecnologia, CIGB Ave. 31 e/158 y 190, Cubanacan, Playa, AP, 6162, CP 10600, Ciudad de La Habana, Cuba, Email: efrain.rodriguez.edu.cu) : Dextranase in sugar industry. Sugar Tech 2009, 11(2), 124-34.

In sugar production, dextrans are undesirable compounds synthesized by contaminant microorganisms from sucrose, increasing the viscosity of the flow and reducing industrial recovery, bringing about significant losses. The use of the dextranase enzyme is the most efficient method for hydrolyzing the dextrans at sugar mills. Some bacterial strains, filamentous fungi and a small number of yeasts have been shown to produce dextranase. The fungal dextranases showed the highest reaction rate at low Brix, with pH and temperature close to 5.0 and 50 °C, respectively, that is, conditions existing in juice extraction. Some of these dextranases formulated in enzymatic preparations have been efficiently used for hydrolyzing dextrans in sugar mill juices. In more advanced stage of the process, where the dextrans have already caused losses, the conditions of temperature and Brix are high. However, although the volumes are smaller, the treatment with these enzymes in syrup showed the need to increase the dose, equaling dextranase consumption. Some thermo tolerant bacterial dextranases identified up to now showed a much reduced specific activity that makes their industrial use unfeasible. The fungal dextranases from Chaetomium sp. have shown the best results on dextrans treatment both in juices and syrups. Any attempt to obtain a new natural or recombinant dextranase enzyme, must be comparable with the Chaetomium enzyme.

^iia1 table, 61 ref

000858   Jiao Z;Wan X;Zhao B;Guo H;Liu T;Wu M (NO, Institute of Nanochemistry and Nanobiology, Shanghai Univ, Shanghai-201 800, Email: Zjiao@shu.edu.cn) : Effects of electron beam irradiation on tin dioxide gas sensors. Bull Mater Sci 2008, 31(1), 83-6.

The effects of electron beam irradiation on the gas sensing performance of tin dioxide thin films toward H₂ are studied. The tin dioxide thin films were prepared by ultrasonic spray pyrolysis. The results show that the sensitivity increased after electron beam irradiation. The electron beam irradiation effects on tin dioxide thin films were simulated and the mechanism was discussed.

5 illus, 9 ref

000857   Jagdale A R;Paraskar A S;Sudalai A (Chemical Engineering and Process Development Div, National Chemical Laboratory, Pashan Road, Pune-411 008, Email: a.sudalai@ncl.res.in) : Cu(OTf)₂ catalyzed biginelli type condensation of aldehydes, β-keto esters and carbamates: synthesis of 3,4-dihydro[1,3]oxazin-2-ones. Indian J Chem-Sect B 2008, 47(7), 1091-5.

Cu(OTf)₂ catalyzes effectively a new multicomponent reaction comprising aldehydes, [3-ketoester and methyl carbamate in acctonitrile to afford substituted 3,4-dihydro[l,3]oxazin-2-ones 60-82% yields. These compounds have been found to show inhibition activity against HL-60 cancer cell.

2 illus, 3 tables, 7 ref

000856   Jacob J;Abdul Khadar M;Lonappan A;Mathew K T (Centre for Nanoscience and Nanotechnology, Kerala Univ, Kariavattom Campus, Thiruvananthapuram-695 581, Email: mabdulkhadar@rediffmail.com) : Microwave dielectric properties of nanostructured nickel ferrite. Bull Mater Sci 2008, 31(6), 847-51.

Nickel ferrite is one of the important ferrites used in microwave devices. In the work, nanoparticles of nickel ferrite is synthesized by using chemical precipitation technique. The crystal structure and grain size of the particles are studied using XRD. The microwave dielectric properties of nanostructured nickel ferrite samples of three different average grain sizes and those of two sintered samples were studied. The parameters like dielectric constant, dielectric loss and heating coefficient of the nanoparticles samples are studied in the frequency range from 2.4 to 4 GHz. The values of these parameters are compared with those of sintered pellets of the same samples. All these parameters show size dependent variations.

5 illus, 1 table, 22 ref

000855   Ganguly A;Raji George (NO, M.S. Ramaiah Institute of Technology, MSRIT POST, Bangalore-560 054, Email: rgeorgemsrit@ediffmail.com) : Asbestos free friction composition for brake linings. Bull Mater Sci 2008, 31(1), 19-22.

An asbestos free friction material composite for brake linings is synthesized containing fibrous reinforcing constituents, friction imparting and controlling additives, elastomeric additives, fire retarding components and a thermosetting resin. The composite shows exemplary friction characteristics and has great resistance to wear and shows good temperature stability.

5 illus, 2 tables, 9 ref

000854   Fatehi K;Moztarzadeh F;Solati-Hashjin M; Tahriri M;Rezvannia M;Ravarian R (Faculty of Biomedical Engineering, Amirkabir Univ of Technology, P.O. Box 15875-4413, Tehran, Iran, Email: m-tahriri@aut.ac.ir) : In vitro biomimetic deposition of apatite on alkaline and heat treated Ti6A14V alloy surface. Bull Mater Sci 2008, 31(2), 101-8.

Titanium alloy (Ti6A14V) substrates, having the ability of biomimetic calcium phosphate-based materials, especially hydroxyapatite deposition in a simulated body fluid (SBF) means of chemical treatment (alkaline treatment) and subsequent heat treatment, was studied. The effects of alkaline treatment time, concentration and heat treatment temperature on the formation of calcium phosphate (carbonate-hydroxyapatite) on Ti6A14V surface were examined. For this purpose, the metallic substrates were treated in 0, 5 and 10 M NaOH solutions at a temperature of 60 or 80°C for 1 and 3 days. Subsequently the substrate was heat-treated at 500, 600 and 700°C for 1 h for consolidation of the sodium titanate hydrogel layer. Finally, they were soaked in SBF for 1 and 3 days. The substrate surfaces were characterized by the techniques commonly used for bulk material such as scanning electron microscopy (SEM) and thin film X-ray diffraction (TF-XRD). With regard to the SEM and TF-XRD results, the optimum process consists of 3 days soaking in 5 M NaOH in 80°C and subsequent heat treatment at 600°C for Ih. It is worth mentioning that the results showed that the apatite formed within 3 days on the specimen surfaces, however, there was no sign of apatite formation in the control samples (without alkaline and heat treatment) which was treated for up to 3 days immersion in SBF.

7 illus, 1 table, 23 ref

000853   Eggleston G;Monge A;Montes B;Stewart D (Commodity Utilization Research Unit, Southern Regional Research Center, ARS, USDA, New Orleans, LA 70124, USA, Email: gillian.eggleston@ars.usda.gov) : Application of dextranases in sugarcane factory: overcoming pactical problems. Sugar Tech 2009, 11(2), 135-41.

Dextranases only have a small market and low volume sales compared to many other industrial enzymes. Consequently, research and development efforts to engineer properties of dextranases to specific conditions of industrial processes have not occurred and are not expected soon. This book chapter highlights the difficulties associated with the practical application of dextranases, that are sometimes applied to hydrolyze dextran in sugar manufacture when bacterial deterioration of sugarcane or sugarbeet has occurred. Less than optimum application existed because of confusion about where to add the dextranase in the factory/refinery and which commercial dextranase to use. The wide variation in activity of commercially available dextranases in the U.S., and a standardized titration method to measure activities at the factory are discussed. Optimization by applying "concentrated" dextranase as a working solution to heated juice is described. Promising short-term technologies to further improve industrial dextranase applications are discussed, as well as the long-term outlook.

^iia5 illus, 2 tables, 26 ref

000852   Dhar S;Shalini K;Shivashankar S A (Materials Research Centre, Indian Institute of Science, Bangalore-560 012, Email: sukanya@mrc.iisc.ernet.in) : Thermodynamic analysis of growth of iron oxide films by MOCVD using tris(t-butyl-3-oxo-butanoato)iron(III) as precursor. Bull Mater Sci 2008, 31(5), 723-8.

Thermodynamic calculations, using the criterion of minimization of total Gibbs free energy of the system, have been carried out for the metalorganic chemical vapour deposition (MOCVD) process involving the β-ketoesterate complex of iron [tris(t-butyl-3-oxo-butanoato)iron(III) or Fe(tbob)₃] and molecular oxygen. The calculations predict, under different CVD conditions such as temperature and pressure, the deposition of carbon-free pure Fe₃O₄, mixtures of different proportions of Fe₃OM₄ and Fe₂O₃, and pure Fe₂O₃. The regimes of these thermodynamic CVD parameters required for the deposition of these pure and mixed phases have been depicted in a 'CVD phase stability diagram'. In attempts at verification of the thermodynamic calculations, it has been found by XRD and SEM analysis that, under different conditions, MOCVD results in the deposition of films comprising pure and mixed phases of iron oxide, with no carbonaceous impurities. This is consistent with the calculations.

8 illus, 1 table, 20 ref

000851   Correcher V;Garcia-Guinea J;Gonzalez-Martin R;Crespo-Feo E;Jimenez-Cordero D (NO, , CIEMAT, Avda. Complutense 22, 28040 Madrid, Spain, Email: v.correcher@ciemat.es) : Study of aluminium oxide from high-alumina refractory ceramics by thermoluminescence. Bull Mater Sci 2008, 31(6), 891-5.

This work is focused on the study of the thermally stimulated blue emission of aluminium oxide (Al₂O₃) that has been removed from twenty different high alumina-rich refractory bricks. The glow curve sensitivity of several alumina grains are defined by (i) a maximum centred at about 165°C that can be decon-voluted into two first order kinetic peaks at 157 and 177°C and (ii) a broad structure over 200-220°C that suggests a continuous trap distribution system. The isolated grains, analysed by means of X-ray diffraction, are composed of 43% of alumina (Al₂O₃), 22% of mullite [72% of Al₂O₃ and 28 % of SiO₂], 12% of leucite (KAlSi₂O₆) and 23 % of sillimanite [Al₂O₃-SiO₂]. The sample characterization has been performed using X-ray fluorescence and scanning electron microscopy.

4 illus, 1 table, 29 ref

000850   Chen P;Wu Q S;Ding Y P;Yuan P S (Chemistry Dep, Chizhou College, Chizhou, Anhui 247000, P.R. China, Email: qswu@mail.tongji.edu.cn) : Synthesis of SrCrO₄ nanostructures by onion inner-coat template and their optical properties. Bull Mater Sci 2008, 31(4), 603-8.

Describes a bio-template method of the squama inner coat of onion for preparing the SrCrO₄ nanostructures including nanospheres, nanorods and dumbbell-shaped superstructure. The method is able to make SrCrO₄ nanoparticles with average diameters in the range of 90-170 nm, SrCrO₄ nanorods with length in the range 0-70-2 μm, width in the range of 80-180 nm, and SrCrC>4 dumbbell-shaped superstructure with length in the range 10-14 μm. The dumbbell-shaped superstructures are assembled by many SrCrO₄ nanowires with length in the range 10-14 μm and width in the range 30-50 nm. The products were characterized by transmission electron microscope, powder X-ray diffraction, UV-Vis spectroscopy and luminescence spectrophotometer. A possible formation mechanism was also proposed. In the preparation, the SrCrO₄ nanostructures were synthesized at room temperature without any surfactants. This new bio-template method will have potential applications in preparation of the nanoscale materials with different morphologies.

10 illus, 19 ref

000849   Chauhan A K;Goel D B;Prakash S (Metallurgical and Materials Engineering Dep, Indian Institute of Technology, Roorkee-247 667, Email: dbgmtfmt@iitr.ernet.in) : Erosion behaviour of hydro turbine steels. Bull Mater Sci 2008, 31(2), 115-20.

The martensitic stainless steel (termed as 13/4) is currently being used for fabrication of underwater parts in hydroelectric projects. There are, several maintenance problems associated with the use of this steel. A nitronic steel (termed as 21-4-N) has been developed as an alternative with the specific aim of overcoming these problems. A comparative study has been made on the erosion behaviour of 13/4 and 21-4-N steels by means of solid particle impingement using gas jet. The eroded surfaces after erosion tests were analysed by scanning electron microscopy. It is observed that the 21-4-N nitronic steel possesses better resistance to erosion in comparison to 13/4 martensitic stainless steel. The austenitic matrix of the nitronic steel possesses high hardness, high tensile toughness and work hardening ability, which results in higher erosion resistance.

6 illus, 2 tables, 19 ref

000848   Chand N;Nigrawal A (NO, Advanced Materials and Processes Research Institute, Habibganj Naka, Bhopal-462 026, Email: navinchand15@indiainfo.com) : Investigations on d.c. conductivity behaviour of milled carbon fibre reinforced epoxy graded composites. Bull Mater Sci 2008, 31(4), 665-8.

Reports the d.c. conductivity behaviour of milled carbon fibre reinforced polysulphide modified epoxy gradient composites. Milled carbon fibre reinforced composites having 3 vol. % of milled carbon fibre and poly sulphide modified epoxy resin have been developed. D.C. conductivity measurements are conducted on the graded composites by using an Electrometer in the temperature range from 26°C to 150°C. D.C. conductivity increases with the increase of distance in the direction of centrifugal force, which shows the formation of graded structure with the composites. D.C. conductivity increases on increase of milled carbon fibre content from 0.45 to 1.66 vol.%. At 50°C, d.c. conductivity values were 1-85 x 10¹¹, 1-08 x 10^-1 and 2.16 x 10^-12 for samples 1, 2 and 3, respectively. The activation energy values for different composite samples 1, 2 and 3 are 0.489, 0.565 and 0.654 eV, respectively which shows decrease in activation energy with increase of fibre content.

4 illus, 2 tables, 12 ref

000847   Boopathy K;Samson Nesaraj A;Rajendran V (Physics Dep, Government College of Engineering, Salem-636 011, Email: boopathy_gce@yahoo.co.in) : Self-propagating combustion synthesis of Pb_1-xSr_xZrO₃ (0 ≤ x ≤ 0.20) ceramics and their dielectric properties. Bull Mater Sci 2008, 31(2), 149-53.

Lead strontium zirconate, Pb_1-xSr_xZrO₃ (0 ≤ x ≤ 0.20) ceramics, were prepared by novel glycine-nitrate self-propagating combustion technique. The crystal structure of the ceramics was investigated as a function of composition via X-ray diffraction (XRD). The XRD patterns obtained on these powders showed the formation of pure orthorhombic phase of lead strontium zirconate without impurities and all the compounds retained the orthorhombic structure. The samples were sintered at 900-1100°C for 2 h. It has been observed that the dielectric constant decreases with increase in strontium content (100 kHz). In all compositions, dielectric constant showed a peak at transition temperature and the magnitude of the peak was found to decrease with strontium doping level.

5 illus, 1 table, 32 ref

000846   Balkaya N;Cesur H (Environmental Engineering Dep, , 34320 Avcilar-Istanbul, Turkey, Email: nbalkaya@istanbul.edu.tr) : Zinc adsorption kinetics by phosphogypsum. J scient ind Res 2008, 67(3), 254-6.

Study reports kinetics of zinc adsorption by phosphogypsum, which was conditioned with lime before batch adsorption. Pseudo-second-order equation was found more appropriate for Zn²⁺ adsorption than pseudo-first-order equation.

4 illus, 25 ref