Sharif Digital Repository

Virtual power plants (VPPs) represent a strategic coalition designed to optimize profits earned and simultaneously help independent system operators (ISOs) cope better with uncertainties associated with the renewable resources. These unions typically comprise generation units, customers, facilities that enhance their profitability, such as electrical energy storage systems (EESSs) and flexible loads. Among the flexible loads, cryptocurrency mining loads (CMLs) possess traits that are well-suited to various flexibility services and could be a source of flexibility in the VPPs while benefiting from its potentials. This paper introduces an innovative VPP configuration that incorporates... 

In urban rail transport systems such as subway, Trains are constantly accelerate and brake, so the braking system is of great importance in energy consumption and constitute about 30 to 40 percent of total energy consumption trains, thus retrieval braking energy will lead to significant savings in urban rail transport systems. In this paper, in the beginning, different storage equipments for storage braking energy have been studied and compared and finally Supercapacitors due to technical and economic features have been selected for the storge of equipment. These systems can be implemented in both stationary and onboard. For precise evaluation and select the appropriate storage system, by... 

Now a days, the ability of measuring the mechanical properties of the living cells in in experiments has been increased. Experiments shows that the stem cells could alter their faith in different mechanical situations, but an integrated model about this phenomenon in literature has not been introduced yet. In this research thesis s minimal cell model (MMC) is developed to capture the behavior of the cells on substrates with varying mechanical properties and morphologies, MMC consists of large scale models for outer membrane of the cell and nuclear envelope, cytoplasmic area, chromatin fibers and Extra cellular matrix. Each component of the MMC will be placed in an integrated software to... 

A Polygonal finite element method without conforming mesh was introduced by the authors for modeling large deformation elastoplastic problems. In this method, the geometry and interfaces of the problem are modeled on a uniform mesh. The boundaries are defined on the uniform background mesh using the level set method. Different polygonal elements will be created at the intersection of the interface and the uniform mesh. Polygonal element shape functions are used for the interpolation. In this paper, the capability of this polygonal finite element approach for modeling large deformational frictionless dynamic contact-impact problems is investigated. Contact interfaces are modeled independent... 

In this thesis, manganese oxide nanoparticles with about 5 nm size were synthesized via solvothermal to maximize surface and active sites for proton relaxation. The synthesized nanoparticles were coated with gentisic acid to acquire suitable colloidal stability and biocompatibility. The nanoparticles showed low cytotoxicity in MTT assay. Electrosteric mechanisim was employed for colloidal stability. This mechanisim doesn’t need high surface charge and thick coat which are vital for particles functionality. Then by cell culture eliminating and adding protamine sulfade, nanoparticles uptake were increased tremendously. In this thesis for first time Prussian blue was utilized for staining... 

Diseases such as cancer lead to extensive conversion in the biological structure of cells. These conversions can overshadow cell function. The dynamics of a cell directly depends on how it interacts with other cells and the extracellular environment. Most of these interactions are associated with the occurrence of mechanical phenomena and are due to forces that the cell has experienced. Cell mechanics manifests itself in the Mechanotransduction, the ability of a cell to sense and respond to external forces. Cancer alters the mechanical properties of the components of the cytoskeleton. Understanding the biomechanical behavior of cells and cytoskeleton can play an important role in early... 

In photocatalitic activity of titana an effective approach to achieve high charge separation efficiency and high level of sensitivity under visible light is coupling it with another semiconductor with smaller band gap and appropriate banding energy structure. achieving all mentioned above, we used bilayer structure and coupled TiO2 with hematite which its small band gap(Eg ~ 2.1 ev) is sensitive to visible light. Bilayer systems of TiO2/Fe2O3 , Fe2O3/TiO2 were fabricated by sol-gel process and variable parameter was upper layer thickness. The layers were deposited on glass substrate via sol-gel process. The upper layers were prepared in different thicknesses in two ways. First, they... 

Recently, quasi 1D (Q1D) structures of materials such as nanowires, nanorods and nanobelts with high surface to volume ratio (A/V) and small grain size devoted an extensive part of researches. This is due to their unique properties and thus various applications in manufacturing of nanometric devices. Niobium pentoxide (Nb2O5) as semiconductor with wide bandgap has been applied in various fields including: electrochromic devices, gas sensors, anti-reflective coatings, capacitors, photocatalysts , field emission and recently; antibacterial systems. In this project , initially niobium thin films was deposited on Si(100) substrate using RF magnetron sputtering method and then niobium oxide... 

Modeling the water flow in cohesive fracture is a fundamental issue in the crack growth simulation of cracked concrete gravity dams and hydraulic fracture problems. Discontinuities in porous materials such as concrete, soil and rock have important role on the mechanical and hydraulic behavior of a multiphase system. The creation and propagation of discontinuities, such as cracks in a multi-physics system, lead to a complex non-linear coupled problem with continuous topological changes in the domain.In this study, a mathematical model is presented for for the analysis of dynamic fracture propagation in the saturated and semi-saturated porous media. The solid behavior incorporates a discrete... 

In recent years, the popularity and applications of Non-Fungible Tokens (NFTs) have increased dramatically. For this reason, especially in the current decade, many researches have been conducted in different fields about the use of these tokens at the global level. One of the important and vital topics in the field of non-exchangeable tokens is the issues related to price prediction and the factors affecting their prices, which are mainly investigated using data analysis approaches. In this research, the factors affecting the price of non-exchangeable tokens of Bored Ape Yacht Club (BAYC) have been studied. These factors include traits, transaction data, rarity scores, transaction volume,... 

In this project, two types of graphene obtained from chemical and chemical vapor deposition (CVD) methods were studied for gas/vapor sensing applications . In chemical method, oxidation and exfoliation of graphite was performed in liquid phase. AFM, XPS, Raman spectroscopy and Uv-visible spectroscopy were indicated that single layers synthesis of graphene oxide (GO) sheets was formed successfully. Reduction of the GO to reduced graphene oxide (RGO) was chemically done by hydrazine as a conventional reducing agent and melatonin as a green alternative. Photocatalytic reduction and hybridization of GO with TiO2 was also studied. TEM, SEM and AFM analyses confirmed nucleation and growth of TiO2... 

Networks and the epidemiology of directly transmitted infectious diseases are fun-damentally linked. The foundations of epidemiology and early epidemiological models were based on population wide random-mixing, but in practice each individual has a finite set of contacts to whom they can pass infection; the ensemble of all such contacts forms a network. Knowledge of the structure of the network allows models to compute the epidemic dynamics at the population scale from the individual-level behaviour of infections.Motivated by the analysis of social networks, we study a model of random net-works that has both a given degree distribution and a tunable clustering coefficient.We consider two...