Sharif Digital Repository

The neutron velocity selector is a device used to produce a monochromatic neutron beam with continuous flux. The purpose of the present study is to investigate the sensitivity of the transmission factor and resolution of a multiblade neutron velocity selector to the various parameters using the McStas software. To this end, two instruments were created using the Arm, Progress_bar, Source_simple, DivMonitor, L_monitor, Guide_channeled and V_selector components of the McStas software. The used V_selector component to simulate the multiblade neutron velocity selector was created by considering three assumptions: 1. The absorption of colliding neutrons to selector blades, 2. No interaction of... 

Simulating signal transduction in cellular signaling networks provides predictions of network dynamics by quantifying the changes in concentration and activity-level of the individual proteins. Since numerical values of kinetic parameters might be difficult to obtain, it is imperative to develop non-parametric approaches that combine the connectivity of a network with the response of individual proteins to signals which travel through the network. The activity levels of signaling proteins computed through existing non-parametric modeling tools do not show significant correlations with the observed values in experimental results. In this work we developed a non-parametric computational... 

A signaling pathway is a sequence of proteins and passenger molecules that transmits information from the cell surface to target molecules. Understanding signal transduction process requires detailed description of the involved pathways. Several methods and tools resolved this problem by incorporating genomic and proteomic data. However, the difficulty of obtaining prior knowledge of complex signaling networks limited the applicability of these tools. In this study, based on the simulation of signal flow in signaling network, we introduce a method for determining dominant pathways and signal response to stimulations. The model uses topology-weighted transit compartment approach and comprises... 

One of the main applications of citation is to find articles that are relevant to a particular article. However, not all citations are equally relevant to the target article. This paper presents an approach to identify the most relevant citation(s). To this end, the Normalized Similarity Index (NSI) is proposed to quantify the similarity between the source and target of a citation base on the co-citations and references shared by them. To validate the method, NSI was calculated for five citation networks and was compared with the peer review grades for the relevancy between the source and the target articles. The results showed a significant correlation between the NSI ranks and those of... 

PV generation variability and uncertainty significantly influence operation of the power systems with high penetration of PV sources. The potential impact of distributed PV generation on ramp rate requirements in the IEEE 24-bus system is evaluated in this paper. PV generation and load are, here, probabilistically modeled using actual data and curve fitting approach. Probabilistic unit commitment (UC) based on unit de-commitment method combined with two point estimate method (2-PEM) is used to determine the ramp rate required to compensate for the PV power fluctuations. The proposed method considers stochastic factors and their effects on the dispatch results. Two scenarios are studied to... 

Energy developments plays a crucial role in the political power, economic growth, social development and environmental degradation of developing countries. Energy consumption in residential sector is an essential issue for providing a large variety of services that are necessary for social life tasks such as heating, cooling, and lighting. Therefore, there is a need for depiction of energy outlook and selection of appropriate strategies as the main pillars of economic and political stability in each society. The main objective of this research is to design and apply a methodology that helps decision makers for simulation, optimization and analysis of the residential sector energy system. The... 

Distributed energy resources (DERs) play an important role in the future vision of distribution energy networks. This paper with the aim of promoting DERs role in energy markets proposes a new framework for the optimal bidding strategy of a Technical Virtual Power Plant (TVPP) in different markets. In the proposed framework, it is assumed that the TVPP energy power is distributed throughout a multi-carrier energy network (MCEN) which consists of district heat networks (DHNs) and a distributed electricity network (DEN). In the MCEN, CHP units are the linkage between DHNs and DEN. With the goal of maximizing the profit of TVPP in different local and wholesale energy markets, a bi-level... 

Following the idea of using unbonded isolators to eliminate the tensile stress and providing a cost-effective isolation system, recent experimental research has shown ordinary unbonded steel reinforced elastomeric bearings (SREBs) as an attractive option for seismic isolation of highway bridges. The focus of current research work is on the evaluation of the seismic vulnerability of a highway bridge isolated by unbonded SREBs through developing fragility curves of the structure. This assessment considers parameters playing a key role in the isolation system behavior, namely the friction coefficient, as well as the isolator aging effects. In this regard, a typical three-span highway bridge is... 

Societal concerns over global warming issues and dependence on fossil fuels have caused the vehicle market share of plug-in hybrid electric vehicles (PHEVs) to grow. A large penetration of PHEVs, however, would likely put higher stress on power systems. To lessen the PHEVs' harmful impacts on the distribution grid, this paper proposes a two-stage charging control strategy modeled on a renewable-based energy hub. In the first stage, a home-based charging control method is formulated in which the charging cost of PHEVs is considered as an objective. Running this procedure by PHEV schedulers in houses, in the second stage of the proposed strategy, the PHEV coordinator agent (PCA) applies a... 

With increment in the penetration of wind energy in power systems, the necessity of considering its impacts on transmission expansion planning (TEP) studies, especially for large scale wind farms, is inevitable. A new multi-objective (MO) optimization transmission expansion planning algorithm considering wind farm generation is presented in this two-paper set. Part I is mainly devoted to derivation of the theory and algorithm. The objective functions used in the TEP studies take into account investment cost, risk cost and congestion cost. The combination of Monte Carlo simulation (MCS) and Point Estimation Method (PEM) is implemented to investigate the effects of network uncertainties. Due... 

This paper is the second part of a two-paper set which comprehensively sets forth an innovative approach in transmission grid reinforcement studies in the presence of wind energy. Part I thoroughly defined the theory and algorithms. Here, to trace the feasibility of the proposed algorithm, three different case studies are implemented on the 24-Bus IEEE Reliability Test System (IEEE-RTS). The optimal solutions in Pareto fronts of different cases are reached, analyzed, and the final solution (optimal plan) of each case is obtained using the fuzzy decision making method. Moreover, in order to analyze the effects of variations in the large-scale wind farm generation on the transmission expansion... 

This paper is the second part of a two-paper set which comprehensively sets forth an innovative approach in transmission grid reinforcement studies in the presence of wind energy. Part I thoroughly defined the theory and algorithms. Here, to trace the feasibility of the proposed algorithm, three different case studies are implemented on the 24-Bus IEEE Reliability Test System (IEEE-RTS). The optimal solutions in Pareto fronts of different cases are reached, analyzed, and the final solution (optimal plan) of each case is obtained using the fuzzy decision making method. Moreover, in order to analyze the effects of variations in the large-scale wind farm generation on the transmission expansion... 

With increment in the penetration of wind energy in power systems, the necessity of considering its impacts on transmission expansion planning (TEP) studies, especially for large scale wind farms, is inevitable. A new multi-objective (MO) optimization transmission expansion planning algorithm considering wind farm generation is presented in this two-paper set. Part I is mainly devoted to derivation of the theory and algorithm. The objective functions used in the TEP studies take into account investment cost, risk cost and congestion cost. The combination of Monte Carlo simulation (MCS) and Point Estimation Method (PEM) is implemented to investigate the effects of network uncertainties. Due... 

Steel Reinforced Elastomeric Bearings (SREB) are mostly designed and used for providing different supporting conditions under service loads; while recent studies have shown remarkable characteristics which help them as a cost-effective isolation system. However, little investigation has been carried out to indicate the influence of parameters affecting the mechanical properties of the bearings under large shear deformations (i.e., the seismic performance as an isolation system). A comparative parametric study was conducted herein through finite element modeling of SREBs. The implemented model was also verified by experimental test results. The hysteretic behavior was studied in both cases of... 

Reduction of large tensile stresses and cost-efficiency has made unbonded isolators an attractive option as an isolation system. Following this idea and the results obtained by various researchers, it is shown that unbonded steel-reinforced elastomeric bearings (SREBs), which are used and designed for non-seismic actions, have inherently acceptable characteristics in tolerating large shear deformations for a cost-effective isolation system and can provide improved structural performance. However, this capacity is neglected in the design process. The current article presents an experimental program to analyze the mechanical properties of steel-reinforced natural rubber bearings without the... 

Smart energy systems can mitigate electric interruption costs provoked by manifold disruptive events via making efforts toward proper pre-disturbance preparation and optimal post-disturbance restoration. In this context, effective contingency management in power distribution networks calls for contemplating disparate parameters from interconnected electric and transportation systems. This chapter, while considering transportation issues in power networks’ field operations, presents a navigation system for pre-positioning resources such as field crews and reconfiguring the network to acquire a more robust configuration in advance of the imminent catastrophe. Also, after the occurrence of the... 

The substantial presence of different uncertainties in energy systems highlights the need for probabilistic analysis of operational and planning studies. Motivated by this fact, a new stochastic planning framework for energy hubs (EHs) is presented in this study based on the probability transformation concept. In the proposed framework, a measure of relative-likelihood impact is developed to estimate the importance of uncertainty sources in the studies, which, in turn, can remarkably reduce the overall complexity of stochastic problems. Step-by-step algorithm for implementation of the proposed framework on planning studies of an EH is also addressed in this study. Three different case... 

Congestion management (CM) is inevitable in today's competitive power markets. A CM method should be fast, fair, effective, and motivational. Moreover, in critical congestions, the system simplification and congestion clearing time are also of considerable importance. All the mentioned features can be found in an intelligent zonal CM. In this paper, using sensitivity analysis and power tracing techniques, a new CM model is developed based on power system partitioning. By the proposed model, a congestion index (CI) is introduced by which a candidate zone(s) is specified including some elements (generators and loads) with the highest CIs which means that they have high participation in... 

Thorium dioxide (thoria) nano-particle was synthesized by employing supercritical water (SCW) as an excellent reaction environment for hydrothermal crystallization of metal oxide particles. This method is ideal for production of ultrafine powder having controlled stoichiometry, high quality, purity and crystallinity. The nano-crystalline thoria was prepared in a stainless steel (316 L) autoclave, fed with an aqueous solution of Th(NO 3) 4.5H 2O as a reactant and took place under SCW condition up to 450 °C for 45 min. The product was recovered and characterized by X-Ray Diffraction (XRD), Thermal Gravimetry Analysis (TG/DTA) and Brunauer, Emmett and Teller (BET) surface area analysis. The...