Sharif Digital Repository

In this paper, free vibration analysis of thin symmetrically laminated skew plates with fully clamped edges is investigated. The governing differential equation for skew plate which is a fourth order partial differential equation (PDE) is obtained by transforming the differential equation in Cartesian coordinates into skew coordinates. Based on the multi-term extended Kantorovich method (MTEKM) an efficient and accurate approximate closed-form solution is presented for the governing PDE. Application of the MTEKM reduces the governing PDE to a dual set of ordinary differential equations. These sets of equations are then solved with infinite power series solution, in an iterative manner until... 

This paper describes the concept and a sample design of a broadband loaded monopole antenna with a novel matching network integrated with the antenna body. The proposed monopole antenna is designed by loading three different lumped loads integrated on a wire antenna and a simple input matching network. Parameters of the matching circuits and the lumped loads optimized by using a genetic algorithm (GA). The proposed antenna loads and the matching network is integrated into the antenna body by the use of printed circuit technology making the antenna fabrication process easy. A prototype of the proposed 1.19-meter monopole antenna is fabricated and measured. The simulation and measurement... 

Electrocoagulation is an effective, fast, and economic method for treatment of industrial wastewaters. In this study, effects of different parameters including electrolysis time, voltage, and pH on the reduction of chemical oxygen demand (COD), lignin, and color in pulp and paper wastewaters were studied. Iron and aluminum were used as anode and cathode electrodes, respectively. Under the optimal conditions (pH 5, 60 min, 10 V), this treatment method led to 85% removal of COD and 78.5% removal of lignin. Furthermore, clear treated water with complete color removal was generated that suggests the application of electrocoagulation for industrial wastewater treatment, especially in pulp and... 

This study investigated the diesel and COD removal from oily wastewater by electrocoagulation. Experiments were conducted in a 2-l reactor using aluminum and iron electrodes. Effects of different parameters including pH (3–11), time (10–60 min), voltage (4.5–10.5 V), supporting electrolyte (NaCl concentration), electrode material and initial diesel concentration (3500–11,000 mg/L) were studied in order to evaluate the efficiency of electrocoagulation. Furthermore, the consumption of energy and the amount of sludge produced by this method were evaluated. The highest removal efficiency (COD removal of 99.1 ± 0.2 % and diesel removal of 98.8 ± 0.2 %) was observed under the following conditions:... 

In this paper, a micromechanical study on rate-dependent behavior of connective tissues is performed. To this end, a hyper viscoelastic constitutive model consisting a hyperelastic part for modeling equilibrium response of tissues and a viscous part using a hereditary integral is proposed to capture the time-dependent behavior of the tissues. With regard to the hierarchical structure of the tissue, strain energy function are developed for modeling elastic response of the tissue constituents i.e. collagen fibers and ground matrix. The rate-dependency is incorporated into the model using a viscous element with rate-dependent relaxation time. The proposed constitutive model is implemented into... 

This study describes the concept and design of a low-cost super broadband dipole antenna with a passive matching network. The proposed dipole antenna is designed in three steps. First, a simple planar dipole antenna with six different loads and a balanced to unbalanced (Balun) transformer is designed by the genetic algorithm optimisation. The position and value of the loads are optimised to achieve an acceptable radiation pattern and voltage standing wave ratio (VSWR) over the desired frequency bandwidth. In the next step, the shape of the printed strip dipole antenna is optimised to improve the frequency response of the designed antenna. Finally, an LC network is added to the antenna feed... 

Micro Arc Oxidation (MAO) process was utilized to fabricate nano bioceramic TiO 2-hydroxyapatite coatings on titanium substrates. Samples were produced in electrolytes contained 1 g/l β-glycerophosphate and 5, 10 and 15 g/l calcium acetate for 3, 6 and 10 min at 350 V. The techniques including XRD, XPS, SEM, FESEM and EDX were employed to study the effect of processing parameters. Hydroxyapatite, anatase, α-tri calcium phosphate and calcium titanate phases as well as 30-60 nm-size crystals were detected in the coating layer. It was also observed that the pore volume would increase by increasing the electrolyte concentration. The growth time was also found to influence the total pore volume.... 

A novel approach for the design of wideband doubly curved shaped reflector antennas is introduced. By assuming a virtual aperture in front of the feed antenna and using a PObased near-field method, a fast and precise method for the design of doubly curved shaped reflector antennas is introduces. To prove the effectiveness of method, a 3-15 GHz prototype is fabricated and tested. © IEEE  

Gold nanoparticles are potentially very attractive components for therapeutic delivery since they can be synthesized with any diameter from 1 to 200 nm to carry a payload of therapeutic molecules into a cell without triggering an immune response. Gold nanoparticles must undergo surface transformations before coupling to therapeutic molecules to become eligible for this purpose. It is now more understood that amine groups can bind to gold nanoparticles strongly, which has enabled surface modification of gold nanoparticles with amino acid lysine through its amine group. These lysine capped gold nanoparticles can further be coupled to therapeutic molecules for delivery purposes. In this study... 

For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble... 

Response surface methodology (RSM) explores the relationships between several explanatory variables and one or more response variables. The main idea of RSM is to use a set of designed experiments to obtain an optimal response. RSM tries to simplify the original problem through some polynomial estimation over small sections of the feasible area, elaborating on optimum provision through a well known optimization technique, say Gradient Method. As the real world problems are usually very complicated, polynomial estimation may not perform well in providing a good representation of the objective function. Also, the main problem of the Gradient Method, getting trapped in local minimum (maximum),... 

To study the rate of energy and momentum loss of a heavy quark in QGP, specifically in the hydrodynamic regime, we use fluid/gravity duality and construct a perturbative procedure to find the string solution in gravity side. We show that by this construction, the position of the world-sheet horizon and thereby the drag force exerted on the quark can be computed perturbatively, order by order in a boundary derivative expansion, for a wide range of quark velocities. At ideal order, our result is just the localized expression of the drag force exerted on a moving quark in thermal plasma, while for a quark whose velocity does not belong to the mentioned range, we predict a nonlocal drag force.... 

We determine the most general form of the covariant drag force exerted on a quark moving through a fluid dynamical flow. Up to first order in derivative expansion, our general formula requires the specification of seven coefficient functions. We use the perturbative method introduced in arXiv:1202.2737 and find all these coefficients in the hydrodynamic regime of a N = 4 SYM plasma. Having this general formula, we can obtain the rate of the energy and momentum loss of a quark, namely the drag force, in a general flow. This result makes it possible to perturbatively study the motion of heavy quarks moving through the Bjorken flow up to first order in derivative expansion  

To stay competitive in the new dynamic market having large fluctuations in product demand, manufacturing companies must use systems that not only produce their goods with high productivity but also allow for rapid response to market changes. Reconfigurable manufacturing system (RMS) is a new paradigm that enables manufacturing systems to respond quickly and cost effectively to market demand. In other words, RMS is a system designed from the outset, for rapid changes in both hardware and software components, in order to quickly adjust its production capacity to fluctuations in market demand and adapt its functionality to new products. The effectiveness of an RMS depends on implementing its... 

In the new competitive dynamic market, manufacturing success and survival are becoming more and more difficult to ensure. In other words, getting the right product with low cost and high quality is not the only key to success. New requirements such as production responsiveness and flexibility should be considered. Reconfigurable Manufacturing System. (RMS) is a new paradigm that enables manufacturing systems to achieve rapid response to market demand. The effectiveness of an RMS depends on implementing key characteristics and capabilities of RMS in system design stage and benefiting from them in utilisation stage. In this paper, we introduced a methodology to adjust rapidly and productively... 

It is well-known that chiral anomaly can be macroscopically detected through the energy and charge transport, due to the chiral magnetic effect. On the other hand, in a holographic many body system, the chaotic modes might be only associated with the energy conservation. This suggests that, perhaps, one can detect microscopic anomalies through the diagnosis of quantum chaos in such systems. To investigate this idea, we consider a magnetized brane in AdS space time with a Chern-Simons coupling in the bulk. By studying the shock wave geometry in this background, we first compute the corresponding butterfly velocities, in the presence of an external magnetic field B, in μ « T and B « T2 limit....