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排序方式: 共有545条查询结果,搜索用时 10 毫秒
51.
Neuro fuzzy model for adaptive filtering of oscillatory signals 总被引:1,自引:0,他引:1
In this paper we have developed a neuro fuzzy model for adaptive filtering of oscillatory signals embedded with white noise. Such type of fuzzy adaptive filters are constructed from a set of fuzzy IF-THEN rules, which change adaptively to minimise the cost function until a desired information is available. Here we have used a generalised cost function for better convergence of the error. This algorithm is simulated on a digital signal processor in order to track the signal and to filter out the disturbances present in the signal at a particular instant of time. The system presented here, can measure both types of information like numerical as well as linguistic. 相似文献
52.
Design of solar thermal systems utilizing pressurized hot water storage for industrial applications 总被引:2,自引:0,他引:2
A large number of industrial processes demand thermal energy in the temperature range of 80–240 °C. In this temperature range, solar thermal systems have a great scope of application. However, the challenge lies in the integration of a periodic, dilute and variable solar input into a wide variety of industrial processes. Issues in the integration are selection of collectors, working fluid and sizing of components. Application specific configurations are required to be adopted and designed. Analysis presented in this paper lays an emphasis on the component sizing. The same is done by developing a design procedure for a specific configuration. The specific configuration consists of concentrating collectors, pressurized hot water storage and a load heat exchanger. The design procedure follows a methodology called design space approach. In the design space approach a mathematical model is built for generation of the design space. In the generation of the design space, design variables of concern are collector area, storage volume, solar fraction, storage mass flow rate and heat exchanger size. Design space comprises of constant solar fraction curves traced on a collector area versus storage volume diagram. Results of the design variables study demonstrate that a higher maximum storage mass flow rates and a larger heat exchanger size are desired while limiting storage temperature should be as low as possible. An economic optimization is carried out to design the overall system. In economic optimization, total annualized cost of the overall system has been minimized. The proposed methodology is demonstrated through an illustrative example. It has been shown that 23% reduction in the total system cost may be achieved as compared to the existing design. The proposed design tool offers flexibility to the designer in choosing a system configuration on the basis of desired performance and economy. 相似文献
53.
Anirban Ganguly Swatilekha Saha Anil K. Bhowmick Santanu Chattopadhyay 《应用聚合物科学杂志》2008,109(3):1467-1475
The main objective of this study was to enhance the performance of acrylonitrile–butadiene–styrene (ABS) plastics for dynamic structural applications, including those of automobile relevance. First, ABS was modified by blending with maleic anhydride grafted styrene–ethylene–butadiene–styrene block copolymer (MA‐g‐SEBS) in various proportions. Squeaking noise characteristics were evaluated by measurement of the frictional behavior in an in‐house fabricated friction testing apparatus, and the results are explained on the basis of the change in surface energy upon modification. Detailed dynamic mechanical analyses (strain, frequency, and temperature sweep) revealed significant improvements in the damping characteristics of the modified ABS, especially that modified with 10 wt % MA‐g‐SEBS, without much sacrifice in its mechanical strength. The modulus values predicted with Kerner's model of the blends were well correlated with the morphological changes upon modification. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
54.
Santanu Mondal Andriy Durygin Vadym Drozd Jose Belisario Zhe Cheng 《Journal of the American Ceramic Society》2020,103(9):4876-4893
In this research, near fully dense single phase bulk multicomponent transition metal nitride (Nb1/3Ta1/3Ti1/3)N1−δ has been successfully synthesized from mixed commercial powders of NbN, TaN and TiN via reaction flash sintering technique. This was performed with an applied pressure of ~ 35 MPa at 25°C under a constant DC electric field (~24-32 V/cm). The flash event, which is the abrupt increase in current (up to ~ 25.2 A/mm2) and temperature, occurred without preheating. The threshold power dissipation on the sample right before the flash is ~ 0.7 W/mm3. The formation of single phase (Nb1/3Ta1/3Ti1/3)N1−δ random solid solution and its compositional uniformity were confirmed by XRD and EDS, respectively. The effects of ball milling duration and limiting current density on phase formation were studied. Simulation based on Joule heating provides an estimate of the ultimate sample temperature of ~ 1850°C. Vickers hardness of the obtained (Nb1/3Ta1/3Ti1/3)N1−δ is 17.6 ± 0.6 GPa, which is comparable to similarly flash sintered ingredient binary nitrides of TaN and NbN. TGA in air shows that the oxidation resistance of (Nb1/3Ta1/3Ti1/3)N1−δ is better than that of TaN and NbN but inferior to TiN. The study demonstrates that reaction flash sintering can be a highly efficient technique for synthesizing bulk multicomponent ceramics for both material fundamental investigations and application development. 相似文献
55.
56.
Santanu Basu Amitava Chakraborty Parukuttyamma Sujatha Devi Himadri Sekhar Maiti 《Journal of the American Ceramic Society》2005,88(8):2110-2113
Nanocrystalline La0.9 Sr0.1 Al0.85 Co0.05 Mg0.1 O3 oxide powder was synthesized by a citrate–nitrate auto-ignition process and characterized by thermal analysis, X-ray diffraction, and impedance spectroscopy measurements. Nanocrystalline (50–100 nm) powder with perovskite structure could be produced at 900°C by this process. The powder could be sintered to a density more than 96% of the theoretical density at 1550°C. Impedance measurements on the sintered samples unequivocally established the potential of this process in developing nanostructured lanthanum aluminate-based oxides. The sintered La0.9 Sr0.1 Al0.85 Co0.05 Mg0.1 O3 sample exhibited a conductivity of 2.40 × 10−2 S/cm in air at 1000°C compared with 4.9 × 10−3 S/cm exhibited by La0.9 Sr0.1 Al0.85 Mg0.15 O3 . 相似文献
57.
Kai-Hsiang Liang Karan Kumar Gupta Chung-Hsin Lu Sudipta Som 《Journal of the American Ceramic Society》2022,105(10):6168-6174
SnO2-coated TiNb2O7 powders were synthesized via the solution coating method in the present research. The SnO2 layers with a thickness of 3–5 nm were homogeneously coated on the surface of TiNb2O7 particles. TiNb2O7 coated with SnO2 of 5 mol% with high Li+ diffusion coefficient delivered the discharge capacity of 319.5 mAh/g, which was 6.6% higher than that of the non-coated samples. The enhancement of capacity for the coated TiNb2O7 was owing to the low charge-transfer resistance of 17.5 Ω in contrary to the non-coated TiNb2O7 (27.8 Ω). SnO2-coated TiNb2O7 possessed an improved capacity retention of 85.2% at 5 C after 100 cycles, superior to the non-coated TiNb2O7 (79.8%). On the other hand, the excessive amounts of SnO2 coating led to the reduction in the capacity of the prepared samples. The excessive amounts of SnO2 layers suppressed the Li+ diffusion and increased the charge-transfer resistance. The obtained results in this study indicated that coating of TiNb2O7 with appropriate amounts of SnO2 significantly improved the electrochemical performance of TiNb2O7. 相似文献
58.
Clean Technologies and Environmental Policy - 相似文献
59.
Siba Prasada Panigrahi Sasmita Kumari Padhy Santanu Kumar Nayak 《International Journal of Adaptive Control and Signal Processing》2010,24(1):41-50
This paper addresses the exhaustive computational complexity of the maximum‐a‐posteriori equalizer and the inefficiency of the conventional decision feedback equalizer (DFE) algorithm in iterative equalization, especially when the higher‐level modulation is used with severely distorted Inter Symbol Interference channels. The new method proposed here improves the bit error rate (BER) performance by computing the extra metric rn+1 using the feedback symbols from previous iteration and combining it with a priori information of the symbols. After each iteration, the hard‐detected symbols are saved in the memory as a priori data for next iteration. We verified the proposed algorithm for Binary Phase Shift Keying and 8‐phase shift keying modulation. The promising simulation results show that the BER performance given by the proposed low complexity DFE algorithm improved dramatically throughout the iterations when the conventional DFE has only insignificant improvement in the process of iterative equalization. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
60.
Understanding the kinetics of the formation and consumption of COS and CS2 in the front end of the modified Claus process will be a significant step towards reducing the environmental impact of these plants. Specifically, homogeneous intrinsic rate expressions are needed for engineering design and simulation, which will lead to new, optimized ways of operating these plants. Hence, a high-temperature kinetic study of the COS decomposition reaction was carried out. Experiments were performed with inlet COS compositions in the range of 0.20-2.33 mol%, with pressures at 101-150 kPa and temperatures at 800-1100°C; these conditions cover the conditions typically encountered in the front end of the modified Claus process. The experimental results showed that COS conversion is dependent on the inlet concentration of COS, which contrasts with previously reported higher temperature studies. Finally, the COS decomposition kinetics were modeled as the sum of two reactions, which provided a satisfactory representation of experimental data. 相似文献