Sharif Digital Repository

Making artificial skin and skin alternatives is one of the most important areas in tissue engineering. Although much progress has been made so far, there is still no definitive cure for second- and third-degree burns. To create new tissue in the body, a suitable substrate for cells is needed, which is called scaffolding, and an ideal scaffold in tissue engineering should mimic the dimensions of extracellular matrix, and nanofibers seem to be the best option for this purpose. Among the methods of manufacturing of nanofibers, electrospun is very easy and accurate method. In previous studies, many natural and synthetic polymers such as chitosan, alginate, collagen, polyathylene oxide, etc.... 

In the industry, there are nonlinear processes that can not be controlled with classical methods. Also, there are many processes that are more than one controlled variable that with classical methods, the design of a multiple input - multiple output controler is very difficult for them as well as the constraints on the inputs and outputs of the process exist, using classical controllers will be far more difficult. A model-based predictive control method for controlling nonlinear processes is useful in addition to having very high efficiency, extended to multi-mode interference together with constraints on the control variables and other controlled Problem with dynamic properties such as... 

In recent years, in addition to the stock market, a market has been created in Iran under the name of commodity exchange market. In this market, the product supplier announces some product specifications and buyers also announce their demand and bid price. The following two situations may occur: 1. The total amount of demand is less than or equal to the amount of supply.In this case all buyers receive the product at their bid price. Obviously, first all buyers announce a price lower than the base price so that if this happens, they can buy the required product at the lowest possible price. 2. If the supply is less than the demand, the market enters the competition. In this way, the new bid... 

One of the novel methods of stabilization of nuclear waste is the use of vitrification technology. In order to stabilize high level wastes (HLLW) in glass, it is required that the elements are in their oxide form. Therefore, it is necessary to evaporate the waste and turn it into a solid form so that the elements can be converted into oxide form in the calcination furnace. Hence, one of the challenges of stabilization is the optimization of evaporation and calcination conditions. In this research, the parameters affecting evaporation were first investigated. Using laboratory measurements of application: temperature (110 to 180 °C), presence of nitric acid (0.5 to 4 mol/L), ratio of zirconium... 

One of the most common spinal surgeries involves spinal fusion or vertebral fixation, which is used to treat various conditions such as intervertebral disc disease, scoliosis (lateral deviation of the spinal column), fractures, infections, or the presence of tumors in the spinal column. In this surgical procedure, the use of pedicle screws and titanium rods prevents motion and friction between two vertebrae. Screws may enter the vertebrae in the wrong position and angle, causing bone weakening, rupture of nerve roots or blood vessels, weakness or lack of sensation in some parts of the body, spinal cord injury, and in severe cases, paralysis of the patient. For this reason, fusion surgery is... 

Project Finance is a novel approach in financing big projects. High debt ratio, independency to promoter credit and establishing a special purpose company, are some of project finance characteristics that could be very beneficial in some projects. Liquid Natural Gas (LNG) is a solution for exporting natural gas to far destination. As economical and environmental benefits of using natural gas have been increased in recent years, LNG industry has been experienced rapid growth. In this project we analyze project finance and then describe economical motivation of using this method in LNG industry of Iran.

 

Cable-stayed bridges are the most economical solution for spans ranging from about 200 to 1000 meters. They have become more popular in recent decades due to their efficiency and appearance. The need to understand their seismic beahvior is apparent and any improvement can be useful. The main purpose of this study is to determine the effect of using three lateral cable arrangement groups namely, cross system, pulley system and spatial lateral cable system with two transversally inclined cable planes on seismic performance of cable-stayed bridges. In this research, the seismic consequences of these arrangements with interactions of key parameters like, the main span length and deck to pylon... 

In the present research, model-based reasoning is introduced and explained based on Giere’s explanation of model. In other word, this research could be regarded as a reconstruction of model in Giere’s books and papers due to prpose a clear explanation of model-based reasoning. In the second chapter, after the introduction, the concept of model in Giere’s distinguished book, “Explainnig Science: A Cognitive Approach” (1988) is introduced and analyzed. In the second chapter, however, the concept of model in Giere’s recent works is traced. “An agent-based account of model” and “focusing on functionality rather than ontology” could be explained as the two important differences between his... 

The purpose of presented thesis, is modeling of the buried pipelines in soil slopes under dynamic loading using experiments on the physical model. Hence, numerical models based on five physical models, which are built and experimented on Sharif University of Technology’s shaking table device, have been analyzed using ABAQUS finite element software. In each model, several pipes are buried in slope, and the angle-wise placement of pipes differs with respect to slope slide. For the purposes of modeling, the experiment box has been modeled as rigid body. In order to model the soil behavior, Strain –dependent nonlinear elasticity, and mohr-coulomb criterion, has been employed. In addition,... 

In recent decades, the earth is affected by climate change and the seasons has been warmer than the last. Furthermore, the efficiency of agricultural irrigation is low, and it leads to surface water drought and decrease in groundwater level. The Middle East is known for its warm desert climate. Lack of water resources is considered the most limiting factor for sustainable agriculture and water management of irrigation is a crucial issue for agriculture in Middle East. So it’s necessary to devote the cropping pattern considering above changes. The FAO56 Penman-Monteith equation is the standardized ETo equation. A comparison was made between 8 selected methods and FAO56-PM. Thus the method... 

In this research the process of incomplete reduction of hematite low iron ore to magnetite in a fluidized bed reactor was investigated. Temperature, composition of reduction air, particle size, and stay time were investigated as effective parameters. In this way, temperatures of 560, 580, 600, 620 and 640 degrees of centigrade, input air with flows of 1.2, 1.3 and 1.4 l/s, particles size of 425-850 µm, 850 µm-1.4 mm, and 1.4-2 mm, stay times of 4, 8, 12, 16, and 20 min were used in this research. The reduced specimens were analyzed by XRD and chemical analysis. The results illustrated that increase of temperature, decrease of input air flow, decrease of particles size, and increase of stay... 

Cardiovascular disease (CVD) currently remains a considerable challenge for clinical treatments. CVDs account for N17.5 million deaths per year and will predictably increase to 23.6 million by 2030. The main purpose is to create human model systems to study the effect of disease mutations or drug treatment on the heart. In addition, engineered cardiac tissues are considered promising candidates to be transplanted to improve the function of diseased hearts. For engineered active tissues/organs, 3D bioprinting can fabricate complex tissue architecture with a spatiotemporal distribution of bioactive substances (cells, growth factors, and others) to better guide tissue regeneration. However,... 

Phospholipid vesicles are able to carry drugs or DNA to infected or cancerous cells. The blood flow can carry them to their target positions but their performance will be enhanced if they complete their attack by swimming in final stages of their journey. Vesicles built only by lipid molecules have rotational symmetry and undergo a random motion in their solvents without having a preferred direction. In this project, we break the symmetrical shape of phospholipid vesicles by a cluster of transmembrane proteins. We use a triangulated model of the membrane, apply the method of multi-particle collision dynamics to the motion of solvent particles, and simulate the motility of vesicles for...