Sharif Digital Repository

In electronic computers, extensive amount of computations required for searching biological sequences in big databases leads to vast amount of energy consumption for electrical processing and cooling. On the other hand, optical processing is much faster than electrical counterpart, due to its parallel processing capability, at a fraction of energy consumption level and cost. In this regard, this paper proposes a correlation-based optical algorithm using metamaterial, taking advantages of optical parallel processing, to efficiently locate the edits as a means of DNA sequence comparison. Specifically, the proposed algorithm partitions the read DNA sequence into multiple overlapping intervals,... 

This article presents a process of numerically predicting and experimentally verifying the dispersion quality and penetration level of fuel particles entering and moving in various directions relative to vortex engine walls. If the length scale of particles considered in this study is not comparable to the chamber length and, furthermore, the density is ignored, the effect of the particle on the flow field can be neglected and a one-way solution will be viable for the problem. The solutions in each case are carried out to estimate the particle trajectory and parameters affecting it. The governing equations are converted to a set of nonlinear, coupled, ordinary differential equations (ODEs)... 

Particle dispersion in the vortex flow has been one of the most interesting subjects in recent years. Bidirectional vortex flow field is an industrial sample of the rotating flow which is used to obtain advantages of better mixing and combustion. In this work penetration and dispersion quality of the particles which are entering from various positions on the vortex engine walls have been numerically predicted. Head side, end side, and sidewall are considered as the entering positions. The particle has been assumed to be a rigid sphere. Initial velocity, diameter, and density of entering the particles are assumed to be known. If the particle length scale is considered not to be comparable... 

Particle dispersion in the vortex flow has been one of the most interesting subjects in recent years. Bidirectional vortex flow field is an industrial sample of rotating flow which is used to obtain advantages of better mixing and combustion. In this work penetration and dispersion quality of particles which are entering from various positions on the vortex engine walls have been numerically predicted. Head side, end side, and sidewall are considered as the entering positions. The particle has been assumed to be a rigid sphere. Initial velocity, diameter, and density of entering particles are assumed to be known. If the particle length scale is considered not to be comparable with the... 

In this research particle trajectory in a bidirectional vortex flow has been numerically predicted and the results experimentally validated. Scale analyses of forces show their order of magnitudes and give a criterion to recognize the order of magnitude of exerting forces on the particle. The particle has been assumed to be a rigid sphere. Initial velocity, diameter, density, and position of entering particle are assumed to be known. If the particle length scale is considered not to be comparable with the chamber length and if particle number density is low, then influence of particle on the flow field is negligible and a one-way solution is applicable. The governing equation is converted to... 

The solution for bulk fluid motion of a bidirectional coaxial vortex for application in vortex engine has been derived. The vortex engine is a novel combustion chamber in which swirl motion of reactants are used to maintain the chamber walls cool. The flow field has been considered both analytically and numerically. The model is based on incompressible, steady, axisymmetric, and non-reactive flow conditions. The governing PDEs are reduced to a system of nonlinear ODEs and then, by a coordinate transformation, their singularity has been relaxed. Solution domain has been decomposed into the inner viscous and outer inviscid regions, then, the velocity and pressure fields are obtained... 

Detection of seizure periods in an epileptic patient is an important part of health care. However, due to the variety in types of seizures and location of them, real-time seizure detection is not straight forward. In this paper, we propose a method for seizure detection from EEG signals in datasets which have both generalized and focal seizures. The proposed method is useful in the situations that we have no prior knowledge about the location of the patient's seizure and the pattern of evolution of seizure location. In the proposed method, first, the artifacts are automatically reduced by Blind Source Separation (BSS) methods. Then, the channels are clustered into two clusters. After that,... 

In this research, effects of excess air ratio and waste gate opening pressure threshold on NOx emission and performance in a turbocharged CNG SI engine are studied experimentally at 13-mode ECE-R49 test cycle. The engine power, boost ratio and charge air temperature are investigated experimentally at the cycle for different waste gate pressure thresholds. A code is developed in MATLAB environment for predicting engine performance and NOx and the results are validated with the research experiments. The effects of excess air ratio on the engine indicated power and specific fuel consumption as well as NOx emission are numerically investigated at WOT by the code. NOx emission of WOT is max at... 

This paper proposes a Low Cost circuit level Fault Detection technique called LCFD for a one-bit Full Adder (FA) as the basic element of adder circuits. To measure the fault detection coverage of the proposed technique, we conduct an exhaustive circuit level fault injection experiment on all susceptible nodes of a FA. Experimental results show that the LCDF technique can detect about 83% of injected faults while having only about 40% area and 22% power consumption overheads. In the LCDF technique, the fault detection latency does not affect the latency of the FA, since the error detection is done in parallel with the addition  

In this paper, a novel reinforcement learning method inspired by the way humans learn from others is presented. This method is developed based on cellular learning automata featuring a modular design and cooperation techniques. The modular design brings flexibility, reusability and applicability in a wide range of problems to the method. This paper focuses on analyzing sensitivity of the method's parameters and the applicability in optimization problems. Results of the experiments justify that the new method outperforms similar ones because of employing knowledge sharing technique, reasonable exploration logic, and learning rules based on the action trajectory  

Because of technological restrictions, it is actually impossible to fabricate smooth microchannels. Therefore, exploring the roughness effects on the flow characteristics at microscale is of great importance for scientific communities. The present investigation deals with the effects of corrugated roughness on the fully developed slip flow forced convection in micropipes. The governing equations subject to first-order slip boundary conditions are solved by means of the straightforward perturbation method. Closed-form expressions are obtained for the dimensionless velocity and temperature distributions, for the friction coefficient and pressure drop, and finally for the Nusselt number. The... 

Thermally developing electroosmotically generated flow of two viscoelastic fluids, namely the PTT and FENE-P models, through a slit microchannel is considered. Both the viscous dissipation and Joule heating effects are taken into account and a step change in wall temperature is considered to represent physically conceivable thermal entrance conditions. Expressions for the dimensionless temperature and Nusselt number in the form of infinite series are presented. In general, the resultant eigenvalue problem is solved numerically; nevertheless, an analytical solution is presented for the regions close to the entrance. A parametric study reveals that increasing amounts of the Peclet number... 

This paper describes optimization of the combustion chamber geometry and injection timing of a new generation of EF7 engine, where CNG is directly injected to the combustion chamber, with the aim of providing the best mixture at low and high speeds. The Multi-Objective Genetic Algorithm (MOGA) is coupled with the KIVA Computational Fluid Dynamics (CFD) code, with grid generation, in order to maximize the flammable mass of the mixture. This would result in better combustion and improved fuel economy. The optimization variables related to the combustion chamber are seven geometry variables and injection timing. Through the present optimization, a great improvement in mixture distribution is... 

The bio-microfluidic systems are usually encountered with non-Newtonian behaviors of working fluids. The rheological behavior of some bio-fluids can be described by differential viscoelastic constitutive equations that are related to PTT and FENE-P models. In the present work, thermal transport characteristics of the steady fully developed electroosmotic flow of these fluids in a slit microchannel with constant wall heat fluxes have been investigated. The Debye-Huckel linearization is adopted and the effects of viscous dissipation and Joule heating are taken into account. Analytical solutions are obtained for the transverse distributions of velocity and temperature and finally for Nusselt... 

This study presents a semi analytical solution for the transient weakly underexpanded jet. Different polytropic processes are compared with available experimental data in the literature to assess the best process for steady and transient weakly underexpanded jets. The steady state results agree reasonably well with the experimental and analytical data. It is also shown that isentropic process evaluates steady injection better than other processes. Tip penetration of transient results was compared with available data in literature, and no exact agreement for isothermal and isentropic is observed. This appears due to the linearization of equation of state. It is suggested that more accurate... 

Since there have been many difficulties in clinical administration of anticancer drugs due to their poor solubility & targeting, development of new biodegradable Nano-carriers can provide good solutions to overcome the most of recent problems to obtain a better controlled release and targeted delivery of drugs with better efficiency and less side-effects. Acidic pH is regarded as a phenotypic characteristic of cancer tumors. Under this acidic condition, it is known that the surface charge of Chitosan-modified nano-particles become more positive. On the other hand, cancer cells are negatively charged. It is worth mentioning that by loading of anticancer drugs into this novel system, a strong... 

This chapter proposes a methodology for optimal dispatch of bilateral electricity contracts, which may endanger the system voltage stability in light of short-term operational planning of a deregulated power system. In this framework the value that each owner of a transaction is willing to pay reflects how much the electricity contract is important to be implemented physically. The proposed model dispatches optimally the bilateral transactions regarding the prices offered by owners of bilateral contracts for reactive power and transmission capacity utilization in one hand and, the total operational costs of reactive power resources in the other hand. The model also includes the limits... 

This paper proposes a methodology for optimal dispatch of bilateral electricity contracts, which may endanger the system voltage stability in light of short-term operational planning of a deregulated power system. In this framework the value that each owner of a transaction is willing to pay will reflect how much the electricity contract is important to be implemented physically. The proposed model dispatches optimally the bilateral transactions regarding the prices offered by owners of bilateral contracts for reactive power and transmission capacity utilization in one hand and, the total operational costs of reactive power resources in the other hand. The model also includes the limits...