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71.
Riya Chakraborty Arjun Dey Anoop Kumar Mukhopadhyay 《Metallurgical and Materials Transactions A》2010,41(5):1301-1312
To understand how hardness, the key design parameter for applications of brittle solids such as glass concerning contact deformation,
is affected by loading rate variation, nanoindentation with a Berkovich tip was used to measure the nanohardness of a 330-μm-thick soda-lime-silica glass as a function of loading rate (1 to 1000 mN·s−1). The results showed for the very first time that, with variations in the loading rate, there was a 6 to 9 pct increase in
the nanohardness of glass up to a threshold loading rate (TLR), whereafter it did not appreciably increase with further increase
in loading rate. Further, the nanohardness data showed an indentation size effect (ISE) that obeyed the Meyer’s law. These
observations were explained in terms of a strong shear stress component developed just beneath the nanoindenter and the related
shear-induced deformation processes at local microstructural scale weak links. The significant or insignificant presence of
shear-induced serrations in load depth plots and corresponding scanning electron microscopic evidence of a strong or mild
presence of shear deformation bands in and around the nanoindentation cavity supported such a rationalization. Finally, a
qualitative picture was developed for different deformation processes induced at various loading rates in glass. 相似文献
72.
Terminalia (Terminalia belerica Robx.) is available in the northeastern region of India. The fruit of terminalia has some medicinal value and its kernel contains 43% oil. The prospect of terminalia oil for biodiesel production is investigated with reference to some relevant properties. The fatty acid profile of oil extracted from terminalia is found comparable with similar seed oils attempted for biodiesel production in this region. Terminalia oil contains 32.8% palmitic acid, 31.3% oleic acid, and 28.8% linoleic acid. The calorific value and kinematic viscosity of terminalia oil are 37.50 MJ/kg and 25.60 cSt, respectively. The calorific value and cetane number of terminalia FAME are within the acceptable limit of the EN 14214 standard. However, the flash point of terminalia FAME (90 °C) is relatively lower than the minimum required standard. Overall, the properties of biodiesel obtained from terminalia seed conform to the existing biodiesel standard. In addition to assisting the national biodiesel mission, the extension and regeneration of forest areas through terminalia planting would help us to curb the seemingly irreversible trend of de-forestation in the northeast region of India. 相似文献
73.
Jeffrey M. Gordon K. C. Ng H. T. Chua A. Chakraborty 《International Journal of Refrigeration》2002,25(8):1025-1033
A novel modular and miniature chiller is proposed that symbiotically combines adsorption and thermoelectric cooling devices. The seemingly low efficiency of each cycle individually is overcome by an amalgamation with the other. This electro-adsorption chiller incorporates solely existing technologies. It can attain large cooling densities at high efficiency, yet is free of moving parts and comprises harmless materials. The governing physical processes are primarily surface rather than bulk effects, or involve electron rather than fluid flow. This insensitivity to scale creates promising applications in cooling personal computers and other microelectronic appliances. 相似文献
74.
This paper presents a comprehensive scheme for automatically generating a broad class of artistic illustrations from photographs. Using strokes as the major building blocks, our system optimizes the stroke attributes subject to the desired rendering style. The stroke attributes are computed adaptively to enable importance-based control of the abstraction level at each pixel. We propose a novel outline detection and refinement paradigm called edge painting to construct an outline map, and from which to derive the pixel-wise importance. We also introduce an adaptive bilateral filter to adaptively guide the curved stroke directions based on the importance map. Given the outline, importance, and direction maps, the system creates the illustration via selecting the representative colors, setting the style parameters, and optimizing the stroke attributes based on simulated annealing. The experimental results show that our scheme facilitates automatic production of artistic illustrations in a wide range of rendering styles. 相似文献
75.
A simple and novel interferometric setup for wave-front testing that uses a cross slit is described. In this method, the test beam illuminates a cross slit placed at the front focal plane of a Fourier lens. It selects two orthogonal slices from the test beam, and the interference of these two beams is observed at a slightly defocused plane near the back focal plane. Fringes of different conical forms (circular, elliptical, or hyperbolic) so obtained can be used for testing a coherent wave front in general. The theory, supported by some experimental results, is presented. An application of the method to the study of the nature of asymmetry in the beam profile of a semiconductor diode laser beam is demonstrated. 相似文献
76.
Pijush K. Mitra Prodyot K. Sarkar Dipti K. As Bimalendu Biswas Aditya B. Chakraborty Krishna Raja 《Fuel》1978,57(10):639-642
A study of the effect of ash yield on the maximum thickness of the plastic layer (MTPL) of some coking coals (as measured by the Sapozhnikov plastometer) has revealed that with an increase in the former the latter in general decre?es. A rectilinear relation approximately exists between the ash percentage (dry basis) and log MTPL values of coals. For the samples studied, a multiple correlation incorporating the rank factor was found to be unnecessary. Higher Fe2O3 and SO3 contents from the coal were found to be associated with higher MTPL values. 相似文献
77.
78.
Kimmons JE Dewey KG Haque E Chakraborty J Osendarp SJ Brown KH 《Food and nutrition bulletin》2004,25(3):228-238
This study used simple rapid-assessment techniques to test the feasibility of increasing the consumption of complementary foods by infants by asking mothers to increase meal quantity or frequency or by altering the viscosity/energy density of the food. The feasibility of using micronutrient supplements either added directly to food or administered as liquid drops was also examined. The study was conducted in rural Bangladesh and involved four separate short-term behavioral change trials. Depending on the trial, fieldworkers recruited 30 to 45 infants 6 to 12 months of age. Following recommendations to increase the amount of food provided to infants, the mean intakes from single meals increased from 40 +/- 23 g on day 1 to 64 +/- 30 g on day 7 (p < 0.05). In a second trial, the mean meal frequency increased from 2.2 +/- 1.3 on day 1 to 4.1 +/- 1.3 on day 7 (p < 0.05). Provision of high-energy-density diets, prepared by decreasing viscosity with alpha-amylase or by hand-mashing rice and dhal into a paste before feeding, increased single-meal energy consumption from 54 +/- 35 kcal to 79 +/- 52 kcal or 75 +/- 37 kcal (p < 0.05), respectively. Both types of micronutrient supplements were well accepted and used according to recommendations. In conclusion, it was possible to change short-term child-feeding behaviors to promote increased food intake, mealfrequency, energy density, and micronutrient consumption. Because each of these interventions lasted for only about 1 week, however, the long-term sustainability of these changes is not known. Moreover, the effect of increased feeding of complementary foods on intakes of breastmilk and total daily consumption of energy and nutrients requires further study. 相似文献
79.
Summary. A new higher-order spectral element (SE) is developed for wave propagation analysis of a functionally graded material (FGM) beam in the presence of thermal and mechanical loading. The element is based on first order shear deformation theory (FSDT) and takes into account the depthwise contraction due to Poissons ratio. A new method of element formulation is employed, which is the most general one and devoid of all previous cumbersome wavenumber and wave amplitude computation. The beam can be subjected to temperature variation in depth direction. This variation is found by solving the one-dimensional heat conduction equation uncoupled from the elasticity equation. The effect of the computed temperature field is subsequently superimposed on the mechanical loading in the form of an equivalent nodal load. Numerical examples are directed towards highlighting the effect of the Poissons contraction on the structural response and stress wave. The spectrum and the dispersion relation are studied in detail. The stress field generated by the element and its difference from the FSDT stress field is outlined. The response of an FGM beam to thermo-mechanical loading is analysed and the effect of thermal loading on the overall response is elicited. 相似文献
80.
Saurabh Garg Surjya K. Pal Debabrata Chakraborty 《Neural computing & applications》2007,16(4-5):407-417
This study compares the performance of backpropagation neural network (BPNN) and radial basis function network (RBFN) in predicting
the flank wear of high speed steel drill bits for drilling holes on mild steel and copper work pieces. The validation of the
methodology is carried out following a series of experiments performed over a wide range of cutting conditions in which the
effect of various process parameters, such as drill diameter, feed-rate, spindle speed, etc. on drill wear has been considered.
Subsequently, the data, divided suitably into training and testing samples, have been used to effectively train both the backpropagation
and radial basis function neural networks, and the individual performance of the two networks is then analyzed. It is observed
that the performance of the RBFN fails to match that of the BPNN when the network complexity and the amount of data available
are the constraining factors. However, when a simpler training procedure and reduced computational times are required, then
RBFN is the preferred choice. 相似文献