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81.
A Fortran IV computer program was developed to calculate the composition at equilibrium of products from a single-stage coal gasification process involving coal, H2 and steam. This program was used to develop equilibrium concentration profiles for various components and heating values of dry product gas as a function of temperature, pressure and percentage steam in a hydrogen-steam mixture feed gas. Based on the results, a useful range for the variables, from the thermodynamic point of view, has been established. 相似文献
82.
This work represents the data on the wear behaviour of 304 stainless steel, commercial grade titanium and commercial grade aluminium without and with different surface treatments, namely ion implantation of boron and nitrogen and overlay coatings of titanium carbide and nitride.The surface treatments were characterized by phase identification, hardness, bend strength, as well as adhesion of overlay coatings. Wear properties were evaluated in adhesive, erosive and abrasive modes of wear.The experimental results showed that surface treatments produced measurable changes in hardness and strength. The results of adhesive wear tests indicated that the wear resistance of all the substrate materials can be considerably improved by overlay coating with superhard materials in dry as well as lubricated test conditions. Ion implantation resulted in improvement of wear properties for only a limited regime of adhesive wear under lubricated conditions and for the abrasive mode of wear. Overlay coatings produced a marked improvement in abrasive wear tests under lubricated conditions on all substrate materials. 相似文献
83.
Subhash Chandra 《Nuclear Engineering and Design》1983,74(2):293-297
The present paper discusses some numerical simulations of two phase dispersed droplet flows obtained with an accident analysis code ANEXDI which employs an algorithm based on the implicit multi-field (IMF) method. The numerical solutions have been found to remain stable up to a moderate volume fraction of the incompressible droplets. The results so obtained compare well with the ones obtained with the computer code SIMMER-II and with an analytical formula for shock speed. The viscosity and drag terms which are often retained only for numerical considerations have been observed to affect flow variables profiles. Often neglected transient force flow terms have been observed to stabilize sometimes numerical results, which are otherwise unstable. 相似文献
84.
Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However,
the temperature of a machined surface is challenging for in-situ measurement. Furthermore, the individual contribution of
tool/work friction and plastic deformation of work materials to surface temperature is very difficult to quantify because
the measured temperature is always the resultant temperature. This lack of understanding on the temperature distribution blocks
the design of effective cutting tool geometries and materials to minimize surface temperature. This study provides a finite
element method based on a predictive model to decouple the contributions of tool/work friction and material plastic deformation
to surface temperature in a dry cutting process. The study shows that the plastic deformation of work material contributes
to the majority of surface temperature, whereas the tool/work friction contribution is secondary. High temperatures are produced
when more materials are plowed under the cutting edge. A large tool/work friction leads to higher surface temperatures, and
the use of a cutting tool with physical properties in process simulation significantly improves the accuracy of predicted
surface temperatures. Residual stress reversal from subsurface maximum residual to surface maximum residual stress may occur
when tool/work friction increases. 相似文献
85.
The effects of progressive ion beam bombardment on freeze-fractured, freeze-dried cultured cells during ion microscopic (SIMS) analysis were studied with scanning electron microscopy (SEM) and ion microscopy. The freeze-fracture, freeze-dry sample preparation method was generally found to preserve cell morphology to a level far exceeding the spatial resolution of the ion microscope, with splitting at the nuclear envelope being the most commonly observed artefact. SEM monitoring of surface topography of an NRK-49F fibroblast after various ion bombardment doses showed relatively uniform erosion of cellular material, with some apparent selective retention of small cytoplasmic granules. Prolonged bombardment produced no detectable lateral elemental translocation. 41K+/24Mg+ signal ratios from Swiss 3T3 fibroblasts and RBL rat basophilic leukaemia cells were shown to vary generally by less than 10% during the course of extended ion bombardment. GM0415 human skin fibroblasts containing engorged lysosomes characteristic of Hurler's Syndrome were used to evaluate the effects of ion bombardment during a typical analysis session, where ion images of 39K+, 23Na+, 40Ca+ and 24Mg+ are sequentially recorded. This cell line was chosen as a worst-case system, because these cells are often thinly spread and possess extreme surface topography. Thin cell edges were shown sometimes to sputter away during analysis, giving misleadingly low ion signals from these regions in some 24Mg+ micrographs. Various nonuniform sputtering phenomena occurring in the submicrometre spatial domain had little or no measurable impact on local intensities in ion micrographs, indicating that freeze-dried, freeze-fractured cells are sampled in a sufficiently uniform fashion that quantitative ion microscopic evaluations of intracellular elemental levels in the general cytoplasmic or nuclear regions are feasible. 相似文献
86.
Subhash Wadhwa Madhawanand Mishra Avneet Saxena 《International Journal of Flexible Manufacturing Systems》2007,19(4):410-442
Agility can be viewed as a need to encourage the enterprise-wide integration of flexible and core competent resources so as to offer
value-added product and services in a volatile competitive environment. Since flexibility is considered a property that provides change capabilities of different enterprise-wide resources and processes in time and
cost dimensions, supply chain flexibility can be considered a composite state to enterprise-wide resources to meet agility needs. Enterprise modeling frameworks depicting
these composite flexibility states are difficult to model because of the complex and tacit interrelationship among system
parameters and also because agility thrives on many business objectives. In view of this, the modeling framework presented
in this paper is based on analytical network process (ANP) since this methodology can accommodate the complex and tacit interrelationship
among factors affecting enterprise agility. The modeling framework forms a three-level network with the goal of attaining
agility from the perspective of market, product, and customer as the actors. The goal depends on substrategies that address
the characteristics of the three actors. Each of these substrategies further depends on manufacturing, logistic, sourcing,
and information technology (IT) flexibility elements of the enterprise supply chain (SC). The research highlights that, under
different environmental conditions, enterprises require synergy among appropriate supply chain flexibilities for practising
agility. In the present research, the ANP modeling software tool Super Decisions™ has been used for relative prioritization
of the supply chain flexibilities. We demonstrate through sensitivity analysis that dynamic conditions do require adjustments
in the enterprise-wide flexibility spectrum.
相似文献
Avneet SaxenaEmail: |
87.
Subhash Deshmane Snehal Deshmane Santosh Shelke Kailash Biyani 《Drug development and industrial pharmacy》2018,44(6):1001-1011
Ambrisentan is an US FDA approved drug, it is the second oral endothelin A receptor antagonist known for the treatment of pulmonary arterial hypertension, but its oral administration is limited due to its poor water solubility. Hence, the objective of the investigation was focused on enhancement of solubility and bioavailability of ambrisentan by solid dispersion technique using natural Daucus carota extract as drug carrier. Drug carrier was evaluated for solubility, swelling index, viscosity, angle of repose, hydration capacity, and acute toxicity test (LD50). Ambrisentan was studied for the saturation solubility, phase solubility, and Gibbs free energy change. Compatibility of drug and the natural carrier was confirmed by DSC, FTIR, and XRD. Solid dispersions were evaluated for drug content, solubility, morphology, in vitro, and in vivo study. Screening of the natural carrier showed the desirable properties like water solubility, less swelling index, less viscosity, and acute toxicity study revealed no any clinical symptoms of toxicity. Drug and carrier interaction study confirmed the compatibility to consider its use in the formulation. Formed particles were found to be spherical with smooth surface. In vitro studies revealed higher drug release from the solid dispersion than that of the physical mixture. Bioavailability study confirms the increased absorption and bioavailability by oral administration of solid dispersion. Hence, it can be concluded that the natural Daucus carota extract can be the better alternative source for the preparation of solid dispersion and/or other dosage forms for improving solubility and bioavailability. 相似文献
88.
Alberto Quintana Ainhoa Altube Eva García-Lecina Santiago Suriñach Maria Dolors Baró Jordi Sort Eva Pellicer Miguel Guerrero 《Journal of Materials Science》2017,52(24):13779-13789
ZrO2-decorated ZnO (ZrO2|ZnO) nanoparticles (NPs) have been synthesized by a facile co-precipitation method in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The ZrO2 amount in the NPs has been varied from 1.0, 2.0, 4.9, to 9.3% by weight. The resulting NPs are heterostructured and consist of a crystalline ZnO core (wurtzite phase) surrounded by an amorphous ZrO2 layer. X-ray diffraction analyses support this observation. The NPs show a narrow size distribution and are slightly elongated. Compared to pure ZnO NPs, the hybrid ZrO2|ZnO ones show enhanced photocatalytic activity toward the degradation of Rhodamine B under UV–Vis light. Such enhancement has been partly attributed to the increased amount of oxygen vacancies when ZrO2 is incorporated into the NPs, as shown by X-ray photoelectron spectroscopy analyses. 相似文献
89.
90.
Arvind?KumarEmail author K.?K.?Sharma Rajender?Kumar Subhash?Chand Ashwani?Kumar 《Journal of Electronic Materials》2017,46(11):6422-6429
We have investigated the structural and electrical characteristics of the Ag/n-TiO2/p-Si/Al heterostructure. Thin films of pure TiO2 were deposited on p-type silicon (100) by optimized pulsed laser ablation with a KrF-excimer laser in an oxygen-controlled environment. X-ray diffraction analysis showed the formation of crystalline TiO2 film having a tetragonal texture with a strong (210) plane as the preferred direction. High purity aluminium and silver metals were deposited to obtain ohmic contacts on p-Si and n-TiO2, respectively. The current–voltage (I–V) characteristics of the fabricated heterostructure were studied by using thermionic emission diffusion mechanism over the temperature range of 80–300 K. Parameters such as barrier height and ideality factor were derived from the measured I–V data of the heterostructure. The detailed analysis of I–V measurements revealed good rectifying behavior in the inhomogeneous Ag/n-TiO2/p-Si(100)/Al heterostructure. The variations of barrier height and ideality factor with temperature and the non-linearity of the activation energy plot confirmed that barrier heights at the interface follow Gaussian distributions. The value of Richardson’s constant was found to be 6.73 × 105 Am?2 K?2, which is of the order of the theoretical value 3.2 × 105 Am?2 K?2. The capacitance–voltage (C–V) measurements of the heterostructure were investigated as a function of temperature. The frequency dependence (Mott–Schottky plot) of the C–V characteristics was also studied. These measurements indicate the occurrence of a built-in barrier and impurity concentration in TiO2 film. The optical studies were also performed using a UV–Vis spectrophotometer. The optical band gap energy of TiO2 films was found to be 3.60 eV. 相似文献