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21.
Avijit Mondal Anish Upadhyaya Dinesh Agrawal 《International Journal of Refractory Metals and Hard Materials》2010
Microwave heating is recognized for its various advantages, such as time and energy saving, very rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved properties. The present paper investigates the feasibility of consolidating tungsten powders through microwave sintering. A comparative analysis has also been attempted between the sintering response of pure tungsten powder compact in a microwave and conventional furnace. 相似文献
22.
Polypyrrole has emerged as one of the highly pursued conducting polymers owing to its high electrical conductivity and good
environmental stability. In spite of its excellent electrical properties, the chemical and thermal stability and processability
are not very satisfactory. The incorporation of a polymer material into an inorganic ion-exchanger provides a high class of
hybrid ion-exchangers with enhanced ion-exchange properties, high reproducibility, high stability, and good selectivity for
heavy metals. A novel organic–inorganic composite-polypyrrole zirconium titanium phosphate has been synthesized using zirconium
titanium phosphate, which is an advanced inorganic ion-exchange material with the qualities listed above. The physicochemical
properties of this composite material are characterized by X-ray, TGA–DTA, AAS, FTIR, SEM, and TEM. The ion-exchange capacity,
pH titrations, elution, and chemical stability were determined to study ion-exchange properties of the material. Distribution
studies for various metal ions revealed that the nano-composite is highly selective for Th(IV). An ion-selective membrane
electrode was fabricated using this material for the determination of Th(IV) ions in solutions. The analytical utility of
this electrode was established by employing it as an indicator electrode in electrometric titrations. 相似文献
23.
Mostafa Khajeh Yadollah Yamini Shahab Shariati 《Food and Bioproducts Processing》2010,88(2-3):227-232
Essential oil of Nepeta persica cultivated in Iran was obtained by steam distillation and supercritical (carbon dioxide) extraction methods. The oils were analysed by capillary gas chromatography using flame ionization and mass spectrometric detections. The compounds were identified according to their retention indices and mass spectra (EI, 70 eV). The effects of different parameters such as pressure, temperature, modifier volume and extraction times (dynamic and static) on the supercritical fluid extraction (SFE) of N. persica oil were investigated. The results showed that under the pressure of 20.3 MPa, temperature of 45 °C, methanol of 1.5% v/v), dynamic extraction time of 50 min and static extraction time of 25 min extraction was more selective for the 4αβ,7α,7aα-nepetalactone. Twelve compounds were identified in the steam-distilled oil. The major components of N. persica were 4αβ,7α,7aα-nepetalactone (26.5%), cis-β-farnesene (4.4%) and 3,4α-dihydro-4aα,7α,7aα-nepetalactone (3.5%). However, by using supercritical carbon dioxide under optimum conditions, only two components have more than 90.0% of the oil. The extraction yield based on steam distillation was 0.08% (v/w). On the other hand, using SFE extraction yield in the range of 0.22–8.90% (w/w) were obtained at different conditions. The results show that, in Iranian N. persica oil, 4αβ,7α,7aα-nepetalactone is a major component. 相似文献
24.
Randall M. German Ph.D. Ronald G. Iacocca Ph.D. John L. Johnson Ph.D. Yixiong Liu Ph.D. Anish Upadhyaya B.S. 《JOM Journal of the Minerals, Metals and Materials Society》1995,47(8):46-48
Liquid-phase sintering routinely is used to form dense composite structures. The technique is generally restricted to high solid contents to ensure rigidity of the compact to achieve net shaping. Experimental conditions present during microgravity processing have allowed liquid-phase sintering over a wider range of liquid-solid ratios than possible on Earth. Early results from experiments performed on the space shuttle} Columbia during 1994 are used to show the novel behavior associated with microgravity conditions. 相似文献
25.
Anish Kumar K. Laha T. Jayakumar K. Bhanu Sankaro Rao Baldev Raj 《Metallurgical and Materials Transactions A》2002,33(6):1617-1626
Modified 9Cr-1Mo ferritic steel (T91/P91) has been subjected to a series of heat treatments consisting of soaking for 5 minutes
at the selected temperatures, starting from the α-phase region (1073 K) to the γ + δ-phase region (1623 K), followed by oil quenching. Hardness measurements, microstructural features, and grain-size measurements
by the linear-intercept method have been used for correlating them with the ultrasonic parameters. Ultrasonic velocity and
attenuation measurements, and spectral analysis of the first backwall echo have been used for characterization of the microstructures
obtained by various heat treatments. As the soaking temperature increased above Ac
1, the ultrasonic velocity decreased because of the increase in the volume fraction of martensite in the structure. There were
sharp changes in the ultrasonic velocities corresponding to the two critical temperatures, Ac
1 and Ac
3. Ultrasonic longitudinal- and shear-wave velocities were found to be useful in identifying the Ac
1 and Ac
3 temperatures and for the determination of hardness in the intercritical region. However, ultrasonic attenuation and spectral
analysis of the first backwall echo were found to be useful to characterize the variation in the prior-austenitic grain size
and formation of δ ferrite above the Ac
4 temperature. The scattering coefficients have been experimentally determined for various microstructures and compared with
the theoretically calculated value of the scattering coefficients for iron reported in literature. 相似文献
26.
Three-axis orthogonal woven fabric composites composed of carbon fibres and epoxy resin have been fabricated. Examined from
micrographs, the fabric weaving yarns were found to be very slender with aspect ratios ranging from 11–13.6. Based upon the
observed geometry, the composite has been modelled by a unit cell comprising wavy yarns. Both elliptical and lenticular cross-sections
were adopted to simulate the slender weaving yarns. Taking into account one-dimensional stress concentration and yarn undulation,
an iso-phase approach has been developed to analyse the composite elastic moduli. A higher weaving yarn aspect ratio was found
to result in a lower modulus. Modulus reduction due to yarn undulation was more significant in weaving directions. Material
characterization has been conducted based upon monotonic tensile and three-point flexural tests, and detailed damage mechanisms
for both loadings have been examined. The onset of damage under tensile loading was found to be z-axis yarn debonding, followed
by debonding and splitting in y-axis yarns. When subjected to flexural loading, yarn debonding, transverse cracking, and interyarn
matrix cracking were the dominant damage mechanisms which appeared on specimen tensile sides. Stress transfer among yarns
and how it relates to the composite damage have been discussed in detail.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
27.
The analysis of heparan sulfate glycosaminoglycans (HSGAGs) variations in human serum at the disaccharide level has a great potential for disease diagnosis and prognosis. However, the lack of available analytical methodology for the compositional analysis of HSGAGs in human serum remains to be addressed to delineate the possible role of HSGAGs on the onset and/or progression of a disease. In this study, we have developed a method for the in-depth compositional analysis of the 12 heparin/HS-derived disaccharides from human serum using a combination of technologies--fractionation, exhaustive digestion, solid phase extraction, and LC-MS/MS. The method exhibits high recovery (72-110%) and good reproducibility (standard deviation of less than 5%) with a low limit of detection and quantification. Errors from the method validation were within 1.1%. Nondetectable non- or low-sulfated disaccharides in human serum were also detected using the optimized protocol. Further applying this method, the comprehensive analysis of HSGAGs compositions in human sera from female donors showed considerable variations in disaccharide patterns and compositions. 相似文献
28.
29.
K. M. Manikandan A. Yelilarasi S. S. Saravanakumar P. Senthamaraikannan Anish Khan Abdullah M. Asiri 《中国化学工程学报》2019,27(11):2807-2814
The exploration of polymer electrolyte in the field of dye sensitized solar cell (DSSC) can contribute to increase the invention of renewable energy applications. In the present work, the influence of imidazole on the poly (vinylidene fluoride) (PVDF)-poly (methyl methacrylate) (PMMA)-Ethylene carbonate (EC)-KI-I2 polymer blend electrolytes has been evaluated. The different weight percentages of imidazole added into polymer blend electrolytes have been prepared by solution casting. The prepared films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-visible spectra, photoluminescence spectra and impedance spectroscopy. The surface roughness texture of the film was analyzed by atomic force microscopy (AFM). The ionic conductivity of the optimized polymer blend electrolyte was determined by impedance measurement, which is 1.95×10-3 S·cm-1 at room temperature. The polymer electrolyte containing 40 wt% of imidazole content exhibits the highest photo-conversion efficiency of 3.04% under the illumination of 100 mW·cm-2. Moreover, a considerable enhancement in the stability of the DSSC device was demonstrated. 相似文献
30.
M. Anish T. Arunkumar B. Kanimozhi J. Jayaprabakar N. Beemkumar V. Jayaprakash 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2019,41(4):451-467
In this study, a combination of thermal conductivity, viscosity, and density characteristics are experimentally probed for attaining maximum heat transfer using MgO-Therminol 55 as nanofluid is reported. Recent studies proved that nanofluids have miserable properties that make them feasibly useful in many applications in heat transfer compared to base fluid.MgO-Therminol 55 nanofluid is synthesized by diffusion of MgO nanoparticles of size 160–190 nm in Therminol 55 at different concentrations (0.05%–0.3%). Thermal conductivity and viscosity are calculated at a temperature range of 30–60°C using kd2 analyzer and Fenske viscometer. Data obtained from the experimental results reveals that when volume concentration is increased with respect to that thermal conductivity increases, viscosity decreases and density decreases at different temperatures. The proposed models were supportive to the experimental data. 相似文献