Sharif Digital Repository

In this thesis, three novel geothermal-based ORC systems are proposed to enhance efficiency and to recover the waste heat recovery. The proposed systems are modeled based on basic ORC system (concept 1), ORC system with internal heat exchanger (concept 2), and regenerative ORC system (concept 3). Accordingly, two thermoelectric generators are introduced into the systems to exploit the waste heat of the system. For this purpose, the condenser is replaced by a TEG unit, while the other TEG unit is employed to recover the waste heat of the reinjected geothermal fluid. A comprehensive numerical investigation is conducted to compare the proposed systems from thermodynamic and thermo-economic... 

In this study, two micro swimmers have been modeled using computational fluid dynamics and the motion specifications have been presented. The mechanisms can be used for different applications like drug delivery, monitoring, doing tasks in dangerous environments like robots and etc… . These moving mechanisms are inspired from a type of plankton named “cladoceran Podon Intermedius”, accordingly we have compared our results with data obtained by particle image velocimetry. For CFD simulation, an unstructured 2-dimensional mesh has been generated. Dynamic meshing has also been utilized in a meshing zone around the moving parts. Unsteady simulations were run for axisymmetric and plane symmetry... 

The use of superhydrophobic surfaces is one the most promising methods for reducing the friction and increasing the flow rate in fluid transfer systems. Since in such systems the surface structure plays a key role, in the first part of this study, the performance of the hierarchical nanostructures is explored. These nanostructures are inspired by the superhydrophobic surface of the lotus leaf. The flow is considered between two walls with hierarchical nanostructures and simulate the system via the molecular dynamics (MD) method. The size of the nanostructures and the distance between them have been studied to find whether a design with maximum flow rate exists. The nanostructures have two... 

During the past 20 years, there has been an ever¬increasing interest in searching for anomalies or features beyond the standard scale¬invariant Gaussian spectrum of the CMB in the hope of finding signals of new physics. In this study, a new type of anomaly on the cosmic microwave background called the Inflationary Cherenkov effect is studied. By first simulating the expected effects and using machine learning methods such as convolutional neural networks, we obtain methods to detect this effect. Afterward, with the help of the detector, we study real data, namely temperature anisotropies of the CMB. Finally, we infer the speed of propagation of scalar field perturbations whose energy runs... 

Millimeter wave imaging systems have unique features and have been used extensively in a variety of applications including medical imaging, construction operations, places with high security such as airports, Nondestructive testing and etc. These systems provide high resolution, due to the order of wavelength which is several millimeter or centimeter in this band. Also in places with high security and for detecting the concealed objects under people’s clothing, these waves can easily pass through the materials and investigate the person’s body without causing health problems. A wide variety of these imaging systems , each with different design parameters and resolutions, have been proposed.... 

The purpose of this study is developing the design means of a high pressure centrifugal compressor impeller for aviational applications i.e. turboshaft engines. The logic and constraints of designing a high pressure centrifugal impeller for a turboshaft engine is different from those of low pressure aerial or high speed industrial ones. This kind of impeller is deployed in a number of advanced generation of aero engines. In this study, the centrifugal impeller design tools are developed using two design methods. Then, the results are compared, validated and corrected with an existing high pressure impeller data. A number of impellers with pressure ratios ranging from 6 to 11 are designed and... 

This study is devoted to the analysis and design of a recently proposed steel-FRP deck system. A methodology is being proposed to analysis the elastic behavior of the proposed deck. In this method the deck is modeled as an equivalent orthotropic plate which is constrained by rotational springs along its edges. An analytical model of the proposed deck is derived by using Rayleigh-Ritz method where the primary Rayleigh-Ritz shape functions are generated from orthonormal polynomials by using Gram-Schmidt procedure. The results of the proposed methodology show good agreement with finite element analysis results. In order to test the applicability of the proposed deck as buildings flooring... 

This experimental study evaluates the implementation of atmospheric water generator (AWG) apparatus for rural households to supply the needed water. Humid (atmospheric) air is sucked into the condenser and passed through an air filter by a fan; since the temperature of the condenser is lower than the ambient air temperature (dew point temperature), the moist in the atmospheric air is condensed and freshwater is collected which is stored in a tank and after 7 stages of purification will be ready to drink.Data of this project is obtained from Kish Island’s weather station to find the average temperature and humidity. Kish Island is chosen for this project because of its high humidity and... 

One of most important type of dams are concrete gravity dams, This structures maintain their stability against the load from their weight. The study of stability of dams is very important issue because Iran is placed on a seismic zone and instability of constructed dams will cause many problems for us. There are two method in study of concrete gravity dams: in first method which is named rigid approach the body of dam consider as a rigid body and by equilibrium equations and traditional strength of material concepts the safety factors of stability and stresses are determined. In second method that is named flexible approach, we should prepare a finite element method from the dam, reservoir... 

Detection of blood diseases is one of the hardest branches of medical science. The human circulatory system mainly consists of three main components namely white blood cells, red blood cells and platelets. Many diseases are diagnosed based on qualitative and quantitative evaluation of these cells, such as cell’s quantity, size, shape and the color of the cells. For example, AIDS and blood cancer cause major changes in components of immune system i.e. white blood cells. Also, some features of red blood cells change in various diseases such as iron deficiency, anemia, thalassemia and other diseases like malaria. Rapid diagnosis and treatment of these diseases has a considerable impact on the...