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2.
Layne T. Watson Kishore Kumar Sankara Luegina C. Mounfield 《International Journal of Engineering Science》1985,23(1):131-137
The flow due to a rotating disk decelerating with an angular velocity inversely proportional to time with either surface suction (or injection) which again varies with time is investigated. The unsteady Navier-Stokes equations are transformed to non-linear ordinary differential equations using similarity transformations. The resulting equations are solved numerically using a globally convergent homotopy method. The flow depends on two non-dimensional parameters, namely an unsteadiness parameter and a suction (or injection) parameter . Some interesting numerical results are presented graphically and discussed. 相似文献
3.
Syntactic foam slabs having uncoated microballoons and paraffin oil surface‐treated microballoons were fabricated and tested for short‐beam three‐point bend test. The work points to the role of paraffin oil coating first weakening the interface between the microballoons and the matrix and hence lowering the efficiency of load transfer from matrix to the fillers (i.e., microballoons). This led to an overall decrement of 71% in the experimentally measured strength value compared to the deduced value for uncoated microballoons' specimens. The large strengths for uncoated microballoons specimens can be traced to the presence of the curvilinear marks in the matrix that, incidentally, are absent in the case of paraffin oil coated specimens. These observations are revealed distinctly in the microscopy of test‐failed specimens. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 687–693, 2005 相似文献
4.
Scanning Electron Microscopic (SEM) studies were carried out on the failure surface of syntactic foam material tested in a short beam three point bend test (SBT) by employing 21 × 15 × 3 mm3 dimension bearing specimens. The syntactic foams were fabricated using glass microballoons in epoxy binder. The failure of the tensile, compression, and shear dominated regions were studied by SEM at different magnifications. The tensile region had characteristic features, such as partial debonding of the microballoons from the matrix and cracking of glass microballoons, apart from matrix cracking and some river pattern features. The compression side was characterized by crushing and collapsing of microballoons, resulting in accumulation of debris with no apparent river pattern for matrix‐rich regions. The midway positions of the SBT failed surface comprised of deformation bands in the matrix and occasional debonding of microballoons. The morphology recorded in the tensile and compression regions corroborated well with the results obtained on these foam samples in those specimens that were subjected to pure uniaxial tension and compression, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 673–679, 2005 相似文献
5.
BK Kishore L Fuming P Maldague PM Tulkens PJ Courtoy 《Canadian Metallurgical Quarterly》1996,74(6):1025-1037
In the companion paper, we report that a single injection of poly-D-glutamic acid causes an acute lysosomal storage condition and apparently impairs the lysosomal fission dynamics. The present paper addresses the mechanisms of these two alterations using a combination of in vivo and in vitro biochemical approaches. After a single intravenous injection, 14C-poly-D-glutamic acid was rapidly cleared from the plasma and appeared in the urine. Yet, a small but sizable fraction of the injected polymer was taken up by the kidney cortex through a saturable process (Kuptake, 150 mg/kg body wt; uptakemax 96 micrograms/g cortex). Analytical subcellular fractionation of cortex homogenates demonstrated that at initial stages, the 14C label was predominantly associated with subcellular particles of intermediate size and low equilibrium density, and was therefore slowly transferred to larger particles equilibrating at high density, then codistributing with the lysosomal hydrolases. At a concentration of 10 mg/ml (equivalent to its estimated concentration in lysosomes), poly-D-glutamic acid formed micronic aggregates ( > or = 10 microns) when brought to solution at pH < or = 6 in relation to its decreased ionization (pKa of lateral chains approximately equal to 4.25). Finally, 1 day after the injection of poly-D-glutamic acid, the activities of several lysosomal enzymes (hexosaminidase, cathepsin B, acid sphingomyelinase, and sulfatase B), but not of all of them (eg, acid phosphatase), were increased in the kidney cortex. We propose that poly-D-glutamic acid reaches lysosomes by adsorptive endocytosis and becomes concentrated within these organelles because its withstands hydrolysis until it forms aggregates or precipitates, causing a decrease in the fluidity or the deformability ("gelling") of the lysosomal matrix. This should alter the dynamics of intercommunication of these organelles by impairing their fission without a proportionate effect on their fusion properties. In addition, the data suggest that the presence of poly-D-glutamic acid directly or indirectly slows down the degradation of several lysosomal enzymes. 相似文献
6.
Mosaliganti K Cooper L Sharp R Machiraju R Leone G Huang K Saltz J 《IEEE transactions on visualization and computer graphics》2008,14(4):863-876
Developments in optical microscopy imaging have generated large high-resolution data sets that have spurred medical researchers to conduct investigations into mechanisms of disease, including cancer at cellular and subcellular levels. The work reported here demonstrates that a suitable methodology can be conceived that isolates modality-dependent effects from the larger segmentation task and that 3D reconstructions can be cognizant of shapes as evident in the available 2D planar images. In the current realization, a method based on active geodesic contours is first deployed to counter the ambiguity that exists in separating overlapping cells on the image plane. Later, another segmentation effort based on a variant of Voronoi tessellations improves the delineation of the cell boundaries using a Bayesian formulation. In the next stage, the cells are interpolated across the third dimension thereby mitigating the poor structural correlation that exists in that dimension. We deploy our methods on three separate data sets obtained from light, confocal, and phase-contrast microscopy and validate the results appropriately. 相似文献
7.
V. R. Pai Verneker K. Kishore C. B. V. Subhas 《Propellants, Explosives, Pyrotechnics》1979,4(4):83-86
Thermal decomposition studies on double-base propellants have been carried out in air and vacuum using differential scanning calorimetric, thermogravimetric and mass spectrometric techniques. Low temperature (90 °C–170 °C) decomposition seems to involve diffusion controlled process, the mechanism in air and vacuum being different. High temperature (170 °–205 °C) decomposition involves bond breakage. 相似文献
8.
Response surface methodology was advantageously used to optimally immobilise a β-galactosidase from chick pea onto alkylamine glass using Box–Behnken experimental design, resulting in an overall 91% immobilisation efficiency. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. Immobilised enzyme showed a shift in the optimum pH; however, optimum temperature remained unaffected. Thermal denaturation kinetics demonstrated significant improvement in thermal stability of the enzyme after immobilisation. Galactose competitively inhibits the enzyme in both soluble and immobilised conditions. Lactose in milk whey was hydrolysed at comparatively higher rate than that of milk. Immobilised enzyme showed excellent reusability with retention of more than 82% enzymatic activity after 15 uses. The immobilised enzyme was found to be fairly stable in both dry and wet conditions for three months with retention of more than 80% residual activity. 相似文献
9.
Kishore K Jena Tapan K Rout Ramanuj Narayan Kothapalli V S N Raju 《Polymer International》2012,61(7):1101-1106
(Hyperbranched polyurethane‐urea)/[(3‐aminopropyl)triethoxysilane]‐ZnO (HBPUU‐APTES‐ZnO) hybrid coatings were synthesized using an inexpensive mixing technique by varying the APTES‐modified ZnO concentration. The mechanical and surface properties of the hybrid coating films were studied and compared with unmodified and modified ZnO. The corrosion, solvent and abrasion resistance show significant enhancement in HBPUU‐APTES‐ZnO hybrids and their properties are increased with increasing APTES‐ZnO concentration. This hybrid coating has opened up an opportunity for automotive topcoat application. Copyright © 2012 Society of Chemical Industry 相似文献
10.
Amit K. Jaiswal Hemlata Chhabra Sachin S. Kadam Kishore Londhe Vivek P. Soni Jayesh R. Bellare 《Materials science & engineering. C, Materials for biological applications》2013,33(5):2926-2936
The aim of this study was to compare physico-chemical and biological properties of hydroxyapatite (HA) and hardystonite (HS) based composite scaffolds. Hardystonite (Ca2ZnSi2O7) powders were synthesized by a sol–gel method while polycaprolactone–hardystonite (PCL–HS) and polycaprolactone–hydroxyapatite (PCL–HA) were fabricated in nanofibrous form by electrospinning. The physico-chemical and biological properties such as tensile strength, cell proliferation, cell infiltration and alkaline phosphatase activity were determined on both kinds of scaffolds. We found that PCL–HS scaffolds had better mechanical strength compared to PCL–HA scaffolds. Addition of HA and HS particles to PCL did not show any inhibitory effect on blood biocompatibility of scaffolds when assessed by hemolysis assay. The in vitro cellular behavior was evaluated by growing murine adipose-tissue-derived stem cells (mE-ASCs) over the scaffolds. Enhanced cell proliferation and improved cellular infiltrations on PCL–HS scaffolds were observed when compared to HA containing scaffolds. PCL–HS scaffolds exhibited a significant increase in alkaline phosphatase (ALP) activity and better mineralization of the matrix in comparison to PCL–HA scaffolds. These results clearly demonstrate the stimulatory role of Zn and Si present in HS based composite scaffolds, suggesting their potential application for bone tissue engineering. 相似文献