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61.
Adel Hatami-Marbini Madjid Tavana Vahid Hajipour Fatemeh Kangi Abolfazl Kazemi 《Applied Soft Computing》2013,13(8):3459-3472
The technique for order preference by similarity to ideal solution (TOPSIS) is a well-known multi-attribute decision making (MADM) method that is used to identify the most attractive alternative solution among a finite set of alternatives based on the simultaneous minimization of the distance from an ideal solution (IS) and the maximization of the distance from the nadir solution (NS). We propose an alternative compromise ratio method (CRM) using an efficient and powerful distance measure for solving the group MADM problems. In the proposed CRM, similar to TOPSIS, the chosen alternative should be simultaneously as close as possible to the IS and as far away as possible from the NS. The conventional MADM problems require well-defined and precise data; however, the values associated with the parameters in the real-world are often imprecise, vague, uncertain or incomplete. Fuzzy sets provide a powerful tool for dealing with the ambiguous data. We capture the decision makers’ (DMs’) judgments with linguistic variables and represent their importance weights with fuzzy sets. The fuzzy group MADM (FGMADM) method proposed in this study improves the usability of the CRM. We integrate the FGMADM method into a strengths, weaknesses, opportunities and threats (SWOT) analysis framework to show the applicability of the proposed method in a solar panel manufacturing firm in Canada. 相似文献
62.
Chasen Ranger Vahid Tari Susan Farjami Matthew J. Merwin Lionel Germain Anthony Rollett 《Metallurgical and Materials Transactions A》2018,49(10):4521-4535
Texture and grain size distribution of the austenite phase at high temperature have distinct effects on the subsequent transformed microstructure and mechanical properties of steel alloys at room temperature. Measurement of austenite at high temperature is not, however, a trivial task especially if orientation maps are desired. Therefore, a technique for determining austenite texture and grain size that was present at high temperature is highly desirable. In this work, we review several pipe samples intended for use as well casing with large variations in toughness and martensitic microstructures at room temperature. Microstructural analysis of the martensite structures could not easily explain these differences due to how martensite forms from austenite. An algorithm was developed to reconstruct the parent austenite at high temperature from martensite microstructure at room temperature. This technique successfully reconstructed orientation maps for the prior austenite in these samples, demonstrating differences in texture, grain orientation spread, and austenite grain size that could account for the differences in mechanical properties. 相似文献
63.
Masoud Ghanei-Motlagh Mohammad Ali Taher Vahid Saheb Maryam Fayazi Iran Sheikhshoaie 《Electrochimica acta》2011,56(15):5376
A novel ion-selective poly(vinyl chloride) (PVC) membrane sensor for Cu2+ ions based on N,N′-(2,2-dimethylpropane-1,3-diyl)-bis(dihydroxyacetophenone) (NDHA) as a new ionophore was prepared and studied. The best performance was observed for the membrane composition, including 30:65:1:4 (wt%) = PVC:DBP:KTpClPB:NDHA. The electrode showed a good Nernstian slope of 30.0 ± 0.5 mV/decade in a wide linear range activity of 3.0 × 10−7 to 1.0 × 10−2 mol dm−3 Cu(NO3)2 with limit of detection 2.5 × 10−7. Sensor exhibited a fast response time (t95% < 10 s) and could be used for about 4 months in the pH range of 3.0–7.4. The proposed potentiometric sensor was found to work satisfactorily in partially non-aqueous media up to 30 (vol%) content of methanol, ethanol and acetone. Applications of this electrode for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, were reported. In order to predict the extraction ability of NDHA for different metallic ions, the complexes [M(NDHA)] and [M(H2O)6] (where M = Cu2+, Co2+, Hg2+, Pb2+, Ag+, Mg2+, Ca2+, Mn2+, Zn2+, Cd2+, K+ and Al3+) were investigated using ab initio theoretical calculations. The metal binding capability was evaluated using the binding energy. Results of our study could be useful for prediction of the extraction power of this Schiff base and could play a guiding role in planning experiments. 相似文献
64.
Control charts are among the simplest of on-line statistical process control techniques. When the quality characteristic is a variable, the p-chart takes time to react to shifts in the production process because of its weak response to small variations in the process mean and variance. In this paper, instead of considering an item to be either conforming or nonconforming, the “degree of nonconformity” based on fuzzy concepts is defined and a fuzzy p-chart based on the mean degree of nonconformity is constructed. It is shown that this chart has a better response to variations in both the mean and the variance of the process. 相似文献
65.
The time evolution of internal friction and shape change in different microstructural states of two Cu-Zn-AI shape memory
alloys has been investigated. In the single-martensite phase state, the monotonic decrease of internal friction with time
is attributed to the pinning of martensite/ martensite interfaces. When the parent phase is present, the change in the internal
friction is associated with the formation of stress-induced martensite and the subsequent pinning of the martensite/parent
and martensite/martensite interfaces. 相似文献
66.
A new world for transistors may be on the horizon. The days of directly implementing custom functionality in transistors, and hence of designers creating their own chips, may be fading away. Prefabricated programmable platforms, considered grossly inefficient just a decade ago, may prevail, leading to lower costs, faster time to market, lower power, and other benefits perhaps not even foreseeable today. 相似文献
67.
The internal friction in a Cu-Zn-AI shape memory alloy has been studied in various microstructural states in a wide range
of stress amplitude. Simultaneous measurements of the corresponding shape change indicate correlations between internal friction
and the deformation mechanisms. It is found that the observed stress-amplitude dependence of the internal friction cannot
be represented by a single formalism. Rather, in different ranges of stress amplitude, where the internal friction mechanisms
are different, separate formalisms are applicable. The comparison of the experimental results with a previously developed
theory is presented. 相似文献
68.
In this research study, a 3D finite element model using ABAQUS software is used to evaluate the rutting performance of reinforced asphalt pavement. In this research study, the effects of three types of geosynthetic layers on the optimum location are studied at temperatures of 20°C, 40°C, and 50°C. According to the model analysis, the middle of asphalt layer is determined as the optimized location of geosynthetic layers in the pavement structure. The results showed that the effect of geosynthetic layers on rutting performance increased with increasing elastic modulus of geosynthetic at high temperature of pavement. 相似文献
69.
Hamid Eskandari‐Torbati Davood Arab Khaburi Vahid Eskandari‐Torbati 《International Journal of Numerical Modelling》2016,29(2):205-221
In this paper, a new predictive direct power control algorithm to control the PWM rectifier based on virtual flux (VF) is presented. In this algorithm, supply network and the line inductances are assumed as an induction machine and so virtual flux space vectors are assumed corresponding with the space vector of the network voltages. Instantaneous active and reactive powers and finally convertor average voltage in both stationary and rotating reference frames are calculated by the virtual flux space vector components. The main advantages of the proposed method are low total harmonic distortion of the input current and low ripple in the instantaneous active and reactive powers and direct current‐bus voltage under harmonic distorted condition of the supply voltage in comparison with voltage‐based predictive direct power control (V‐PDPC) method. Proposed VF‐PDPC method with space vector modulation switching strategy was tested in simulations and compared with the V‐PDPC method. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
70.
Vahid Behjat Mohammad Javad Amroony Boushehry 《International Journal of Numerical Modelling》2016,29(4):592-608
The transverse flux permanent magnet synchronous generator has a great potential for use in direct‐drive wind energy conversion systems due to its large pole numbers, high torque, and power density. This research work develops dynamic model of a single‐side transverse flux permanent magnet synchronous generator for use in a small‐scale gearless wind energy conversion system. For acquiring the parameters of the considered generator, required for dynamic modeling, 3D finite element model of the machine is developed and analyzed in both magneto‐static and transient modes. Field‐oriented control approach is employed for tracking maximum power point from the variable wind speed. The simulation results illustrate an accurate response of the system to the wind speed variation and proper performance of the developed dynamic model and control approach of the system. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献