Sharif Digital Repository

Climate change and energy security are key drivers for future energy policy. While energy security has been a pillar of energy policy for about a century, concern about climate change is more recent and is bound to radically change the landscape of energy policy. Policy makers are now under increasing pressure to address these twin challenges: to develop cost-effective policies that will both ensure the security of our energy system and reduce greenhouse gas emissions.
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in... 

This research deals with numerical simulation of triaxial test to determine behavior of non-cemented and cemented ballast aggregates used in base and subbase of roads and railroads. Ballast aggregates, thanks to their high strength and durability, are widely used in various fields including dam, river, road construction, and railway. One of the most widespread uses of this material is in the road body, and according to the recommendation of the British Highway Center, the materials used in the road body are well-graded gravel with the maximum size of 20 mm. Cement is also used as a corrective material to enhance the performance of road bodies. Therefore, knowing the characteristics of these... 

Social media can be helpful to people in vast areas, especially in queuing systems, in the real world there is remarkably unknown information like service time, average waiting time or average queue length to customers, thus people are likely to share their experiences to posterior customers who want to use the same service. This research examines the impact of user-generated reviews, on the performances of a Markovian queuing system, we assumed that customers are not aware of the service rate, therefore they will assist next customers by writing reviews about their service time they had experienced. We intend to examine the impact of information on queueing performance such as system... 

New technology-based firms (NTBFs) are the driving force behind creating innovation and technology in countries and can play a crucial role in job creation and economic growth. These companies also facilitate technology transfer and strengthen the absorptive capacity of national innovation systems. Therefore, given the externalities of these companies, as well as their significant role in promoting innovation, governments around the world implement policies to support these firms. In Iran, the Vice President for Science and Technology has implemented policies to support NTBFs since 2013. Recently, a few studies have been carried out to evaluate these policies. However, the number of these... 

In this project, Olive Mill Wastes (OMW) has been considered as a raw material for a bio-refinery. The project is consisted of a design section using SuperPro Designer software and an experimental section. The biorefinery was designed using the software after conducting a survey on the production of different value added material from OMW. The designed process consisted of xanthan gum, methane gas and agriculture fertilizer production. As much as 15000 L of the diluted OMW (to 50% of the initial concentration) is purified and 88 Kg xanthan gum (in 7 days), 2840 Kg methane gas and 200 Kg fertilizer in 25 days are produced at the same time.
In the experimental section, effect of applying... 

In recent decades, the soil-structure effect has been considered in seismic studies. Most of these researches are based on the premise that the foundation is bonded to the ground. However, several examples of structures that experienced uplift have been reported. Uplift affects the soil-structure contribution and nonlinear behavior of the structure. It seems that a parametric study should be done for the simultaneous effects of the soil-structure interaction, foundation uplift and inelastic behavior of the superstructure. Although the most accurate methods to estimate the behavior of structures is the nonlinear time history analysis, this analysis is very time consuming. The endurance time... 

In this research, multi-disciplinary design optimization (MDO) of a flying vehicle has been done based on the flight simulation. A meta-heuristic algorithm called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA) has been used for optimization. Since solving a MDO problem is a time consuming process, a RBF neural network has been used in the optimization algorithm as a surrogate model. The new algorithm, called MARCOMA+NN, has been tested with some standard benchmarks. MDO problem has six disciplines consists structure, aerodynamic, propulsion, guidance, control, and fire control. The MDO problem has 31 design variables and two objective functions. The objective functions are... 

A cooperative aerial system to defense a Ground Station (GS), against an Incoming aerial Targets (IT) is presented. GS is surrounded by given terrains and a group of homogenous Unmanned Aerial Vehicles (UAVs) are employed using a novel online guidance algorithm in a decentralized manner. The proposed algorithm includes loiter, midcourse and terminal phases. During loiter; UAVs follow an optimal circular path. IT is supposed to approach GS along an optimal low altitude trajectory with respect to the terrains. UAVs are informed the initial position and velocity of IT and they are unaware of IT trajectory. Each UAV decides on whether to engage with IT or not, and shares its decision with other... 

PVDF (polyvinylidene fluoride) magnetic nanocomposite films were prepared by solution casting using two types of nanomagnetic particles: (i) magnetic nanoparticles synthesized by using an alkaline solution of mixed ferrous/ferric salts along with oleic acid as a coating agent at 70˚C; (ii) Fe3O4 nanoparticles prepared by hydrolysis of aqueous solution of ferrous/ferric salts with potassium hydroxide at room temprature. Scanning electron microscopy (SEM) showed that the PVDF magnetic nanocomposite had a porous structure with Fe3O4 nanoparticles dispersed inside the porous polymer matrix. The presence of crystalline magnetite within the polymer matrix was confirmed by X-Ray diffraction method... 

In this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start... 

In this research a novel intelligent back-stepping control method is developed. This method is robust to sensor noise and external disturbances. In addition, the controller is robust under model uncertainty. This controller does not need precise knowledge of system parameters. This method is based on three methods of: back-stepping control, least squares estimation and a fuzzy compensator. This controller is used to control quadrotor stand witch is like an inverse pendulum. In quadrotor stand modeling, the inverse pendulum effect is considered too, witch is one of the innovations of the research. By doing various simulations, the validity of controller is tested. Also the performance of the... 

Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to... 

The purpose of this paper is to design an integrated controller and observer (ICO) for a nonlinear system using genetic programming. ICO is a function that constructs control command directly from the measured state variables of the system. It means that, this function should imitate the behavior of the observer and controller and control the system with acceptable performance in different initial conditions, at the presence of disturbances and system uncertainties. The complexity of this design method, is not related to the complexity of the plant, in fact, the complexity in plant just effects at run time, but the design procedure does not change. So, if exact model of plant exist, using... 

Nowdays much of the organic solid waste and wastewater is buried using centralized and traditional methods. This leads to many problems, including groundwater pollution, methane emissions into the atmosphere and rapid transmission of disease. In order to avoid these problems, using a decentralized approach can be a good solution. In this study, recovery of organic waste and wastewater of residential buildings using anaerobic digester as a decentralized way, have been examined. Using experiments, the optimum mass ratio of organic solid waste and wastewater is obtained as 80% and 20% respectively. Biogas production model is developed using mass balance and Balance of electrons in redox... 

Multi-disciplinary design optimization (MDO) of a surface to air flying vehicle has been done in this research, on the basis of flight simulation. The MDO problem have five disciplines consists of aerodynamic, propulsion, guidance, control, and fire control. Multiple campaign scenarios are defined. The MDO problem has 31 design variables and two objective functions. The objective functions are flying vehicle weight and miss distance. A new meta-heuristic algorithm has been designed to solve multi-objective optimization problems. The new algorithm has been called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA). The MARCOMA can solve large-scale and multi-objective problems and... 

In this Thesis, an unmanned multicopter with a new structure is modeled and a nonlinear controller is designed for it to track the trajectories precisely. The multicopter in this thesis, has six propellers with a hybrid propulsion system (a combination of fuel and electric propulsion system) that has the ability to carry more payload and maintain more flight duration compared to electric multicopters. In the beginning, the performance characteristics and technical specifications of the hexacopter are presented. For modeling, first the equations of six degrees of freedom movement of the hexacopter are derived by the Newton-Euler method. In the next step, the forces and torques applied to the...