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91.
Raman J. Rombouts P. Weyten L. 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(6):1601-1614
92.
93.
Of concern in the paper is the distribution of thermal stresses in the vicinity of a penny-shaped crack in a thick elastic
plate made of a non-isotropic material. The problem pertains to the situation where the crack is opened by a prescribed normal
pressure and a prescribed heat-flux or a prescribed temperature. 相似文献
94.
Anil Kumar Mandeep Kaur Rajeev Kumar Pinaki Ranjan Sengupta Vasantha Raman Gopal Bhatia Kedar Nath Sood 《Journal of Materials Science》2010,45(5):1393-1400
Carbon–copper composites with varying copper to carbon ratio of 0.66–1.5 (by weight) were developed from coal-tar-pitch-derived
green coke (as such or modified with natural graphite) as carbon source and electrolytic grade copper powder at different
heat treatment temperatures (HTTs) of 1000–1400 °C. The physical, mechanical, and electrical properties differ depending upon
the HTT and also on copper to carbon ratio (Cu/C). The composites prepared at HTT of 1100 °C having Cu/C ratio of 0.66 and
0.9 exhibited a high bending strength of 150 and 140 MPa, bulk density of 2.63 and 2.81 gm/cm3, electrical resistivity of 1.6 and 0.96 m Ω cm and shore hardness of 88 and 84, respectively, in spite of well-known inadequate
wettability between copper and carbon. Increasing the temperature from 1100 °C for processing of the composites deteriorated
the properties mainly due to the loss of copper through melting above 1100 °C as revealed by X-ray, scanning electron microscopy,
thermal analysis and EDAX studies. 相似文献
95.
NC physical verification effort can be considerably reduced by analytical modelling of NC tool path. A computer algorithm was developed to graphically emulate the tool path while machining flat polygonal objects. The orientation of the cutter center line relative to the object was then varied and several configurations were generated. For each configuration the total path was evaluated and plotted. Nature of the plots showed that an analytical optimization of the path is possible. In order to make the model more rigorous, attempts are being made to include the effects of the cutter tool life on the total path. 相似文献
96.
In this communication, a study is carried out to evaluate an annual thermal and exergy efficiency of a hybrid photovoltaic thermal (HPVT) air collector for different Indian climate conditions, of Srinagar, Mumbai, Jodhpur, New Delhi and Banglore. The study has been based on electrical, thermal and exergy output of the HPVT air collector. Further, the life cycle analysis in terms of cost/kWh has been carried out. The main focus of the study is to see the effect of interest rate, life of the HPVT air collector, subsidy, etc. on the cost/kWh HPVT air collector. A comparison is made keeping in view the energy matrices. The study reveals that (i) annual thermal and electrical efficiency decreases with increase in solar radiation and (ii) the cost/kWh is higher in case of exergy when compared with cost/kWh on the basis of thermal energy for all climate conditions. The cost/kWh for climate conditions of Jodhpur is most economical. 相似文献
97.
Superalloys are used in aggressive atmospheres in aero-engines and land-base gas turbines. IN738LC is an important superalloy
used in gas turbines. Strengthening Ni3(Al,Ti,Nb) type precipitate phase in this superalloy goes through size and morphological changes with time and temperature.
Experimental observations suggest precipitate motion as a whole in the matrix leading to agglomeration of nearby precipitates
for coarsening, which is in contrast to the traditional Ostwald ripening. Likewise, contrary to the conventionally accepted
view of constant activation energy, experimental data in this study indicate varying activation energy, which causes coalescence
and relates to the precipitate size in the form of an increasing polynomial. 相似文献
98.
Santanu K. Maiti 《Transactions of the Indian Institute of Metals》2008,61(2-3):211-215
We explore a novel transport phenomenon by studying the effect of disorder on electron transport through a thin film of varying disorder strength with the distance from its surface. A simple tight-binding model is used to describe the film which is attached to two metallic electrodes, where the coupling of this film to the electrodes is treated through the use of Newns-Anderson chemisorption theory. It is found that, in the strong disorder regime the current amplitude through the film increases with the increase of the disorder strength, while it decreases in the weak disorder regime. This strange behavior is completely opposite to that of a conventional disordered system. Our results also predict that the electron transport is significantly influenced by the finite size of the thin film. 相似文献
99.
A new scheme for elastic–plastic finite element analysis has been proposed for the study of stable crack growth (SCG) from initiation to instability in both mode I and mixed modes (I and II). The scheme is based on node-release technique and helps to determine the variation of fracture load with crack extension without requiring much computer storage and time. The scheme permits predictions of load variation with load line displacement (LLD), maximum fracture load, crack tip current plastic zone and crack edge profile. In the analysis the condition for crack extension at every stage of the SCG is considered to be governed by CTOA/COD reaching a critical value. The scheme of analysis is different from the ones proposed by earlier investigators. The whole SCG is analysed in a few stages using the ANSYS software and a single discretization. Element arrangement in the discretization is decided from the very beginning; it has a capability of accommodating changes in boundary conditions arising out of crack extension in the later stages. Each stage is analysed afresh ignoring state of stress–strain reached at a material point at the end of the previous stage. Case studies on both mode I and mixed mode presented considering AISI 4340 steel, which is widely used in nuclear power industry, indicate that the SCG through it can be characterized in terms of a single COD or CTOA. Predictions for the initiation and maximum fracture loads in both the cases compare very closely with the experimental data reported. The results presented also include the value of critical COD/CTOA (0.035 mm/0.0875 rad) characterizing the SCG through the steel and show that the initiation load is not significantly affected by crack tip radius up to 0.05 mm. 相似文献
100.
Images account for a significant and growing fraction of Web downloads. The traditional approach to transporting images uses TCP, but this is overly restrictive for image data. Our analysis shows that the in-order delivery abstraction provided by a TCP-based approach prevents the receiver application from processing and rendering portions of an image when they actually arrive. Thus an image is rendered in bursts interspersed with long idle times rather than smoothly. This paper describes the design, implementation and evaluation of an image transport protocol (ITP) for image transmission over loss-prone congested or wireless networks. ITP improves user-perceived latency using application-level framing (ALF) and out-of-order application data unit (ADU) delivery, achieving significantly better interactive performance as measured by the evolution of peak signal-to-noise ratio (PSNR) with time at the receiver. ITP runs over UDP, incorporates receiver-driven selective reliability, uses a congestion manager (CM) to adapt to network congestion and is customizable for specific image formats (e.g., JPEG and JPEG2000). ITP enables a variety of new receiver post-processing algorithms such as error concealment that further improve the interactivity and responsiveness of reconstructed images. Performance experiments across a variety of loss conditions demonstrate the benefits of ITP in improving the interactivity of image downloads at the receiver 相似文献