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991.
992.
Ali YazdaniE. Salahinejad J. MoradgholiM. Hosseini 《Journal of Alloys and Compounds》2011,509(39):9562-9564
Recently, a number of novel methods based on accumulative roll bonding (ARB) have been introduced to produce particulate metal matrix composites. Nonetheless, the microstructure uniformity from the reinforcement distribution viewpoint in the different planes of ARBed composite sheets has not been focused up to date. This paper aims to compare the evolution of the B4C particles distribution in nanostructured Al-10 vol.% B4C composites prepared by ARB in the rolling direction-normal direction (RD-ND) and transverse direction-normal direction (TD-ND) planes. From optical microscopic evaluations quantified by the radial distribution function analysis, it is realized that the homogeneity in the RD-ND planes is in excess of the TD-ND planes. In addition, transmission electron microscopy reveals the development of nanostructures in the Al matrix after seven ARB passes. 相似文献
993.
Detection of Leakage Freshwater and Friction Factor Calibration in Drinking Networks Using Central Force Optimization 总被引:1,自引:1,他引:0
Inverse Transient Analysis (ITA) is a powerful approach for leak detection and calibration of friction factors in pressurized
pipes. Through this method, a transient flow is initiated and pressures are measured somewhere in the system. Then, a nonlinear
programming (NLP) problem with a least-squares criterion objective function is developed to minimize discrepancies between
the measured and calculated pressures at measurement sites. Solving the raised NLP results in the problem’s unknowns being
leakage specifications and pipe friction factors. For this purpose, various optimization techniques may be utilized. This
issue is a major challenge for ITA-based methods. The present work aims at applying the new method of Central Force Optimization
(CFO) to the problem of ITA. CFO is a deterministic metaheuristic inspired by gravitational kinematics in which small objects
in space are dragged by bigger ones. Herein, the concept and main structure of CFO are represented as well as of CFO. A reference
pipe-network is considered to be solved using the ITA equipped with CFO. The results are then discussed compared to the previous
works. It is concluded that CFO is easy to implement, computationally efficient and has a remarkable performance in solving
leak detection problem. 相似文献
994.
Ali Shams‐Nateri 《Color research and application》2010,35(1):29-33
Derivative spectrophotometry is one of the most important techniques that can be used to determine the dye concentration. In addition, principal component analysis (PCA) is a linear method to condense the dimensionality of large numbers of absorbance spectra. In this work, PCA and derivative spectrophotometry techniques are used to improve the accuracy of Beer's law prediction of the concentrations in three‐component dye mixtures. The performance of the new method is compared with the normal Beer's law by calculation absolute error, relative error, and ternary relative error of prediction. As obtained results indicate, the prediction accuracy of dye concentration prediction in PCA‐derivative spectrophotometry method is higher than normal Beer's law method. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010. 相似文献
995.
Ali El Hafidi Bruno Martin Alexandre Loredo Eric Jego 《Mechanical Systems and Signal Processing》2010,24(7):2198-2209
This study is composed of three essential parts. The first part describes an indirect semi-experimental method which is used to reconstruct the excitation force of an operating diesel engine from the acceleration data measured at the mounting points. These internal forces can not be directly measured with force sensors; they have to be derived from the dynamic deformation of the engine support, so a theoretical analysis is carried out to derive the equations for the force re-construction.The second part deals with prevention of low frequency vibration of the powertrain from spreading to the rest of the vehicle. Three uncoupling techniques are used to minimize these vibrations. The first technique reduces the non-diagonal elements of stiffness matrix. The second technique uses the elastic axes decoupling criterion. The third technique uncouple the torque roll axis (TRA) by using the previously determined excitation efforts.In the third part, numerical and experimental results are discussed. The solicitations deducted and the positions of mounts allowing decoupling of the powertrain are presented. 相似文献
996.
Diallyldimethylammonium chloride, which is an acidic salt with numerous applications, was polymerized in water at three different monomer concentrations and at three different pHs which the monomer is in charged form. Reactions were investigated by the automatic continuous online monitoring of polymerization technique. Conversion, molecular weight, and reduced viscosity were monitored. The reaction is found to be second‐order with respect to monomer. Rate constants and molecular weights tend to increase with pH and concentration. POLYM. ENG. SCI., 54:1350–1356, 2014. © 2013 Society of Plastics Engineers 相似文献
997.
Ali Akbar Ramezanianpour Amirreza Pilvar Mahdi Mahdikhani Faramarz Moodi 《Construction and Building Materials》2011,25(5):2472-2479
There are several factors and test methods for evaluating the durability of concrete. In recent years a great deal of attention has been paid to research and development of relationships of these parameters for production of sustainable concretes: water penetration and Rapid Chloride Penetration Test (RCPT) methods which are most commonly used to evaluate the permeability of concrete are two of the most famous methods specified by BS EN-12390-8:2000 and ASTM C1202 respectively. Concrete surface resistivity (SR) test is also a suitable indicator for concrete penetration and chloride ion permeability. It is a non-destructive, simple, rapid and economical method that can also be used on site.The present study is an exploratory research concerned with the relationship of these methods. Based on the correlation of concrete resistivity with water penetration and Rapid Chloride Penetration Test (RCPT) results, two new models for relating these parameters are presented. 相似文献
998.
Aygül Küçükgülmez Ali Eslem Kadak Mehmet Celik 《International Journal of Food Science & Technology》2010,45(12):2645-2649
This study aims to compare chemical, physical and sensorial parameters of the Wels catfish (Silurus glanis), hot smoked using vine, poplar, lemon tree and oak sawdust as well as corncob. Significant differences (P < 0.05) in proximate composition were found between fresh and smoked samples; however, the changes in fatty acid composition were less significant. In the fatty acid composition of control group, monounsaturated fatty acids (41.60%) had the highest share in fatty acids, which was followed by saturated fatty acids (29.95%) and polyunsaturated fatty acids (28.34%). The major fatty acids were observed to be C16:0, C18:0; C16:1 n‐7, C18:1 n‐9c, C18:1 n‐9t and C18:2 n6c. There were significant differences (P < 0.05) between the groups considering their colour measurement results. General preference criteria such as appearance, odour, texture, colour and taste were chosen for the sensorial analysis, which were rated by the panellists. According to the results of overall appearance, the fillet pieces smoked with lemon tree (9.00), poplar (8.66), corncob (8.00), oak (7.33) and vine (5.33) sawdust were determined as the most preferred, in order. 相似文献
1000.