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31.
Nilrudra Mandal H. Roy B. Mondal N. C. Murmu S. K. Mukhopadhyay 《Journal of Materials Engineering and Performance》2012,21(1):17-24
In the light of attractive wear characteristics as well as high strength to weight ratio, extensive research on Al-based Metal
Matrix Composite (MMC) have been carried out globally in the last two decades. However, very limited research has been pursued
on tribological behavior of Al-based MMC under combined action of rolling and sliding. This study investigates the wear behavior
of 6061 Al-alloy/SiC with 10 vol.% SiCp against hardened and tempered AISI 4340 steel under combined rolling-sliding conditions. 23 factorial design of experiments have been carried out to see the effect of few parameters, i.e., contact stress, speed and
duration with respect to wear. The interaction effect has also been studied by 3D graphical contours. A mathematical model
is developed using regression analysis technique for prediction of wear behavior of the MMC and adequacy of the model has
been validated using analysis of variance (ANOVA) techniques. Finally, the optimization of parameter has also been done using
Design Expert software. The results have shown that Response Surface Methodology (RSM) is an effective tool for prediction
of wear behavior under combined sliding and rolling action. It is also found that the wear of MMC is much lower than hardened;
tempered AISI 4340 steel and rolling speed has the maximum influence in wear of both materials under investigation. 相似文献
32.
We consider a Lorentzian manifold M which is globally hyperbolic. We define a metric on C(p, q), the set of all equivalence classes of causal curves connecting two causally related points p and q. We show that C(p, q) is a complete metric space with the metric thus defined. Here, by completeness we mean that every Cauchy sequence (a sequence with a tendency to converge) in C(p, q) finds a point in it to converge. We also give an example to show that the result does not hold in general when the spacetime is not globally hyperbolic. The work is in line with research on causality in relativistic spacetimes. 相似文献
33.
Swapan Kumar Ghosh Rajib Bhattacharyya Murari Mohan Mondal Tapobrata Sanyal 《Journal of Natural Fibers》2015,12(5):457-480
In the last quarter of the twentieth century, a new class of materials, Geosynthetics, emerged prospectively leading significant innovation in the design of geotechnical and geoenvironmental systems. Geotextiles have proven to be among the most versatile and techno-economically viable ground modification materials playing a significant role in modern pavement design and maintenance techniques. With the growing environmental concern across the globe, technologists, researchers have inclined towards the natural geotextile where Jute Geotextile (JGT) is one of the potential candidates. But, JGT has been restricted mainly as underlay in road construction. Hence, there is an urgent need to design and develop a precise innovative fabric as overlay on existing pavements and other emerging civil works to stay technically and economically competitive in the global market. Such a fabric will not only prove techno-economically viable but will also reduce the carbon foot-print generation to a large extent. This paper delineates the development of Grey Jute Paving Fabric (GJPF) followed by its bituminization with suitable type and grade of bitumen to develop Bituminized Jute Paving Fabric (BJPF). The BJPF will enhance the life of the overlay thereby reducing the cost of maintenance as well as serving as a partial substitute of bitumen mastic. 相似文献
34.
Micron-sized nanoporous silver powder with pore size of ~100–160 nm and specific surface area of ~4.7–5.5 m2/g was synthesized from three mechanically alloyed Ag-Zn powders (composition: 25, 50 and 75 at.% Zn). Dealloying was carried out at free corrosion conditions in NaOH, HCl and AgNO3 solutions. Both partial and complete dealloying were obtained by suitable choice of electrolyte and time of exposure. Zn in the solution after dealloying was recovered in the form of ZnO nanoparticles with particle size of 55.7 ± 18 nm. The effect of composition and electrolyte on the degree of dealloying was also studied. 相似文献
35.
Sangeeta Santra Avik Mondal Aloke Paul 《Metallurgical and Materials Transactions A》2012,43(3):791-795
Diffusion-couple experiments are conducted in the Fe-Pt system. The phase boundary compositions of the phases measured in
this study are found to be different than the compositions published previously. In the γ-FePt solid solution, the interdiffusion coefficient increases with the Pt content up to 25 at. pct Pt. Fe is the faster diffusing
species in this phase. The trend in the interdiffusion coefficient is explained with the help of calculated driving force
for diffusion. To reduce errors, the average interdiffusion coefficients are calculated in the FePt and FePt3 compounds. 相似文献
36.
SiO2–CaO–Na2O–P2O5–ZrO2 based bioactive glasses with different compositions of SiO2 and yttrium stabilized ZrO2 were prepared by the conventional melt quenching technique. The effects on the chemical–mechanical properties of bioactive glasses due to the addition of ZrO2 by replacing SiO2 were investigated. Microstructure and phase behavior were studied by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction analysis. Compressive strength, porosity, Vickers hardness, and Young’s modulus were measured as mechanical properties. Bioactivity and cell viability were investigated by immersion in simulated body fluid and MTT assay analysis. Osteosarcoma cell proliferation on the specimen surfaces was examined by confocal laser scanning microscopy. The results showed that replacing SiO2 with ZrO2 helps the bioactive glass to be completely vitrified at comparatively lower sintering temperature than conventional Bioglass®. The mechanical properties were also improved without compromising biocompatibility. Bioactive glass containing 10 wt% ZrO2 and 35 wt% SiO2 showed compressive strength of 399.71 MPa, Young's modulus of 22.3 GPa, Vicker’s hardness of 502.54 HV, and porosity of 26 vol%. 相似文献
37.
The encapsulation of 1,8-naphthalic anhydride (NAN), 9-dicyanomethylenefluorene (9-DCF), acenaphthenequinone (ANQ), and 4-chloro-7-nitrobenzofurazan (NBD-Cl) by diethylpyrrole-bridged bisporphyrin (H4DEP) and its dizinc(II) analogue (Zn2DEP) are employed to investigate the structural and spectroscopic changes within the bisporphyrin cavity upon substrate binding. Synthesis and X-ray structures of all four encapsulated host-guest complexes (H4DEP⋅NAN, H4DEP⋅9-DCF, Zn2DEP⋅ANQ, and Zn2DEP⋅NBD-Cl) are reported here. The binding constant calculations show strong 1 : 1 binding between the hosts (H4DEP and Zn2DEP) and the guests (NAN/9-DCF/ANQ/NBD-Cl). 1H-NMR spectra also support the retention of the host-guest assemblies in solution. Negative and positive shifts of the reduction and oxidation potentials, respectively, indicate that it is difficult to reduce/oxidize the encapsulated complexes. The emission intensities of the bisporphyrins (H4DEP and Zn2DEP) are substantially quenched in all the complexes, owing to photoinduced electron transfer from the excited state of the bisporphyrins to guest molecules. All the experimental evidence is further substantiated by DFT calculations. Such an efficient electron transfer is only possible when the donor and the acceptor moieties are in close propinquity to each other, which eventually lowers the reorganization energy. 相似文献
38.
Krishnendu Chatterjee Thomas A. Henzinger 《Journal of Computer and System Sciences》2012,78(2):394-413
We summarize classical and recent results about two-player games played on graphs with ω-regular objectives. These games have applications in the verification and synthesis of reactive systems. Important distinctions are whether a graph game is turn-based or concurrent; deterministic or stochastic; zero-sum or not. We cluster known results and open problems according to these classifications. 相似文献
39.
The potential of grid-connected solar PV system in Bangladesh was estimated utilizing GeoSpatial toolkit, NASA SSE solar radiation data and HOMER optimization software. Financial viability of solar photovoltaic as an electricity generation source for Bangladesh was also assessed utilizing a proposed 1-MW grid-connected solar PV system using RETScreen simulation software for 14 widespread locations in Bangladesh. The technical potential of gird-connected solar PV in Bangladesh was calculated as about 50174 MW. The annual electricity generation of the proposed system varied depending on the location between 1653 MWh and 1854 MWh, with a mean value of 1729 MWh. Several different economic and financial indicators were calculated, such as the internal rate of return, net present value, benefit-cost ratio, cost of energy production and simple payback. All indicators – for all sites – showed favorable condition for development of the proposed solar PV system in Bangladesh. The results also showed that a minimum of 1423 tons of greenhouse gas emissions can be avoided annually utilizing the proposed system at any part of the country. 相似文献
40.