Sharif Digital Repository

Cylinders are one of the most applicable components in industry. According to the application of these elements, reinforcement and stiffening are the common ways to enhance mechanical properties of them. Nowadays, by advent of new materials such as functionally graded materials (FGMs), a novel method of improving these structures is discovered. By application of FGMs, many physical and mechanical characteristics of these structures can be modified. In this thesis, vibration analysis and frequency optimization of a stiffened cylinder made from FGMs are performed. FGM which is employed in this investigation is made from two different materials, to have better modal properties which cause in... 

Nowadays, variable generation and renewable energy resources are increasingly penetrating the energy systems to supply the users' demand at the distribution grid. Variable Energy Resources (VER) can provide energy at a lower cost, and they also guarantee cleaner energy. Still, the uncertainty and variability from these resources' output can affect the net-load of the system at each hour. Besides, the issue of energy balance has always been a challenge for the energy distribution networks. A comprehensive way to unravel this problem is to use flexible resources. One of the crucial issues in the flexibility debate is meeting this need by different energy resources. It is always an issue for... 

In recent years, electric vehicles (EVs) have emerged as an effective solution to reduce pollution caused by the use of fossil fuels in the transportation sector. While EVs contribute to improved air quality, managing their charging and discharging processes is crucial. To address this, EV aggregators act as intermediaries between EVs and the power grid, primarily responsible for controlling the charging and discharging of a fleet of EVs with the objective of maximizing their profits. On the other hand, to reduce fossil fuel consumption in electricity generation, efforts are underway to transition consumers into prosumers and equip residential complexes with distributed energy resources... 

Hydroxyapatite is the most substantial inorganic constituent of bone tissue which displays splendid biocompability and bioactivity. Nevertheless, its mechanical properties is not utmost appropriate for a bone substitutes. Therefore, it is used to improve the mechanical properties of polymer matrix composite scaffolds. In the present work polycaprolactone as a polymeric matrix was employed to fabricate hydroxyapatite-polycaprolactone biocomposite scaffolds via in situ route. Solvothermal method was employed to synthesize in situ hydroxyapatite in polymer matrix. Porous scaffolds were fabricated via freeze-drying/porogen leaching. Physical, mechanical (compressive module and compressive... 

With the advances made in the last century as well as increasing consumption of non-renewable energy sources and the risk of completion of the resource, developed countries, development and use of renewable energy are taken. In the area of renewable resources, solar energy, is always available as a source, clean and inexhaustible, as one of the most important sources of renewable energy, is known. With the advancement of technology, the use of renewable energy in important industries, especially in the aerospace industry to become more common, so that examples of it in the construction of UAVs and airships is exposed to solar. In this thesis can power loop system consists of two subsystems... 

The present work has proposed an integrated methodology for combined gas & electricity distribution network expansion planning, which considers network expansion constraints (substation installation, feeder/pipeline installation, etc), load growth, and conversion technologies. The planning aims to determine the optimal reinforcement of existing energy network to meet the load growth in the planning horizon. To take the advantages of new technologies, CHP, fuel cell, & microturbine have been included in the problem.This paper employs gravitational search algorithm (GSA) to solve multi-objective problem, including minimization of cost, voltage drop, & pressure drop. GSA that introduced in... 

Optimizing and reducing energy consumption will be a feature of smart cities in the future. In addition to the technical aspects of a technology, one of the most important obstacles to its lack of development is not considering economic factors. Investigating the economics and calculating the cost of using IoT systems in the energy sectors of a smart city is one of the most important issues. Using existing systems in buildings or adding limited and inexpensive hardware to make a building smart can make smartening a cost-effective operation and more widespread. In this research, a proposed architecture based on edge processing is described. In addition to receiving and displaying camera... 

The aim of this project is decentralized control of a group of robots (swarm robots); such that the aggregation maneuver, leader following, Identification and imaging the target, will be performed so good as to make a three-dimensional model of the target from these images. Swarm robots consist of a number of similar and limited features robots which interaction in a group of robots, will lead to special features for the group. Any agent of group decides what to do only with its local information from the environment. Swarm robots are more applicable for the jobs in which a distributed perception from the environments needed, for example space exploration and military operations.In this... 

The purpose of determining orientation and position of a rigid-body is specifying its attitude and position with respect to a specified reference frame in order to using in controller. Since there is no sensor that can directly measures the attitude and position, we have to estimate those variables by observers. In this thesis we derive a new and explicit neccesary and sufficient condition for observability of the rigid-body kinematic equation. Also we propose a new observer for estimating the attitude and position of the rigid-body. The special feature of the proposed estimator is that it use only a single landmark and is globally and exponentially stable. In the next step we study the... 

In the last two decades, Supply Chain Management has become an integral part of sciences such as Management and Industrial Engineering. A key issue in this concept is how to coordinate the activities of the members of the chain in order to improve the performance of the whole system. In this thesis, the main concentration is on production, pricing and lot-sizing policies in a two-stage supply chain with a producer and a retailer. The producer manufactures the final product and vends it to the retailer, and the retailer sells it to the final customer. The customer’s demand is under iso-Elastic pattern that is one the four most popular price-sensitive demand functions. Moreover, in attempting... 

Objective: Stability is important to prevent falls during occupational and daily living activities. Control parameters such as speed, direction of motion and external load can affect stability pattern. The purpose of this study was to evaluate the effect of the mentioned control parameters on stability control pattern.
Methods: Kinematic data (rotation angles) to 19 healthy volunteers and 19 patients with low back pain associated with repeated trunk bending motion in eight different conditions of speed (high and slow), direction (symmetric and asymmetric planes) and external load (with and without load), was evaluated. Since the volunteers do during dynamic movements, they must also be... 

Cryptocurrency miners by solving complex mathematical calculations are responsible for verifying the transactions made in the blockchain network as well as maintaining its security, and as a reward for these activities, they receive bitcoins from the network. The devices used to mine cryptocurrency in order to perform the aforementioned calculations need high electricity consumption, so that the main cost of mining is related to its electricity consumption. For this reason, the ever-increasing development of the blockchain network, as well as the significant growth of the value of Bitcoin, has increased the number of cryptocurrency miners, especially in countries with low electricity costs.... 

The power systems’ net-load variability and uncertainty would aggravate significantly as the penetration of Renewable Energy Resources (RERs) in power systems increases. In response, power system researchers have introduced a new concept, namely flexibility, to quantitatively and systematically deal with unavoidable features of RERs. In power distribution systems as the connection point of power systems with customers, there are many opportunities for improving the flexibility level of systems. Nowadays, the emergence of prosumers has created new opportunities for distribution system operators in providing the system with different services of flexibility in distribution systems. Therefore,... 

To study the structure of materials, among materials containing hydrogen, an instrument called the "small-angle neutron scattering instrument" is used. Having a monochromatic neutron beam is the most basic component of this instrument. This beam is often produced using a device called the "neutron velocity selector". The neutron velocity selector is a rotating mechanical piece that allows for passage of neutrons at a certain speed, according to its rotational speed. In fact, this device produces a monochromatic neutron beam with continuous flux. Until now, it has been designed and manufactured in a variety of models, which are generally divided into two groups of multi-disc and multi-blade... 

In this thesis, the bidding strategy of prosumers in transactive energy markets is analyzed. Considering the repaid increase in utilizing installations that convert multiple energy together, the concept of multi-carrier energy studies has been highlighted. Moreover, with the advent of district heating networks, thermal energy markets have gained much attention lately. The agent who participates in such markets can appropriately benefit from the inherent interdependencies between various energy carriers depending on their prices in different energy markets. This market player is technically called to pose an energy hub. In this regard, to deploy the inherent abilities of such an energy...