Sharif Digital Repository

This paper considers optimal synthesis of a special type of four-bar linkages. Combination of this optimal four-bar linkage with on of it's cognates and elimination of two redundant cognates will result in a Watt's six-bar mechanism, which generates straight and parallel motion. This mechanism can be utilized for legged machines. The advantage of this mechanism is that the leg remains straight during it's contact period and because of it's parallel motion, the legs can be as wide as desired to increase contact area and decrease the number of legs required to keep body's stability statically and dynamically. "Genetic algorithm" optimization method is used to find optimal lengths. It is... 

Novel high capacity swelling nanoporous hydrogel (NPH) was synthesized via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) hybrid backbone, after hydrolysis of this system. The Taguchi method as a strong experimental design tool was used for its optimized synthesis. The Taguchi method was applied for the experimental and standard 9 orthogonal array (OA) with four factors and three levels for each factor. A series of NPHs were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of... 

The effects of H2O/SiO2, TMAOH/SiO2, Na/(Na+K), and SiO2/Al2O3 ratios in the parent gels on the crystallization of nanoparticles of T-type zeolites were studied. A Taguchi orthogonal experimental design with the above-mentioned parameters (each at three levels) was used to optimize the experiment parameters by the analysis of variances (ANOVA). Applying the Taguchi method significantly reduced the time and cost required for optimization. The synthesized products were characterized by X-ray diffraction and scanning electron microscopy. As a result of the Taguchi analysis, H2O/SiO2 and TMAOH/SiO2 were the most influencing parameters for the synthesis of zeolite T. © 2009 WILEY-VCH Verlag GmbH... 

Multifunctional magnetic shape memory polymer (SMP) nanocomposites with high sensitivity was synthesized through inclusion of silane functionalized nanodiamond@Fe3O4 (S-NDF) hybrid nanoparticle into polycaprolactone (PCL) based polyurethane acrylate (PUA) matrix followed by in situ crosslinking of the matrix. Highly biocompatible and superparamagnetic nanodiamond(ND)@Fe3O4 nanohybrids were synthesized through in situ co-precipitation method. The morphological analysis suggested that S-NDFs filled PUAs (2 to 9 wt% loadings) well interacted with both soft and hard domains of the matrix. The base polymer and the nanocomposites presented excellent shape fixity ratio (above 97%) and shape... 

Background: A new design for a methanol plant is proposed in which CO 2 addition, as one of the important parameters, is used to optimize the synthesis gas composition. An attempt has been made to assess the environmental features as well as the process operability of the proposed plant, in which the required CO 2 is provided from reformer flue gas. As a starting point, simulation of a conventional reference methanol case (RMC) and also the proposed green integrated methanol case (GIMC) are performed to obtain operational and kinetic parameters. In order to compare properly GIMC and RMC, the objective function is defined so that SynGas production, and thereby methanol production, in the GIMC... 

SAPO-34 zeolite-like particles were successfully synthesized at high temperature environment. An L9 orthogonal array of the Taguchi method was implemented to investigate the effects of experimental conditions to prepare SAPO-34 with respect to crystallinity of the final product phase. The results showed that the favorable phase crystallinity was improved by increasing the hydrothermal synthesis temperature and organic template content, whereas increasing the water content in synthesis mixture decreased the crystallinity. No significant changes in crystallinity of the final products were observed by increasing the synthesis duration. In addition, zeolite SAPO-5, which was formed as the... 

Adapting natural phenomena rendering for realtime applications has become a common practice in computer graphics.We propose a GPU-based multi-band method for optimized synthesis of "far from coast" ocean waves using an empirical Fourier domain model. Instead of performing two independent syntheses for low- and high-band frequencies of ocean waves, we perform only low-band synthesis and employ results to reproduce high frequency details of ocean surface by an optimized iterative up-sampling stage. Our experimental results show that this approach greatly improves the performance of original multi-band synthesis while maintaining image quality. © Springer-Verlag 2009  

The synthesis of a novel superabsorbent hydrogel with natural hybrid backbone via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) under classic thermal conditions is described. The Taguchi method as a strong experimental design tool was used for synthesis optimization. A series of hydrogels were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum hydrogel was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in... 

In this study, a method was described for the extraction of three antibiotic residues from cow milk samples using a graphene oxide–starch–based nanocomposite. The prepared nanocomposites were employed as an extractive phase for micro-solid phase extraction of antibiotics from cow milk samples. The extracted antibiotics, i.e. amoxicillin, ampicillin and cloxacillin, were subsequently analyzed by high-performance liquid chromatography–ultraviolet detection (HPLC–UV). Important variables associated with the extraction and desorption efficiency were optimized. High extraction efficiencies for the selected antibiotics were conveniently achieved using the starch–based nanocomposite as the... 

Exploring bi-functional electrocatalysts with excellent activity, good durability, and cost-effectiveness for electrochemical hydrogen and oxygen evolution reactions (HER and OER) in the same electrolyte is a critical step towards a sustainable hydrogen economy. Three main features such as high density of active sites, improved charge transfer, and optimized electronic configuration have positive effects on the electrocatalyst activity. In this context, understanding structure–composition–property relationships and catalyst activity is very important and highly desirable. Herein, for the first time, we present the design and fabrication of novel MOF-derived ultra-small Ru/RuO2 nanoparticles...