Sharif Digital Repository

In this study designing and manufacturing of high-temperature fluidized bed reactor were performed. These reactors are based on the contact of fluid with solid particles and balancing the weight of the solid materials. In the manufactured reactor, reduction of manganese de oxide to manganese oxide was done by carbon monoxide produced from incomplete combustion. The most important parameters in the reduction rate are: bed temperature and reduction gas concentration. Materials were injected into the reactor under the pressure of 1.13 mmHg and temperature of 787 ℃ in the bed depth of 4 cm for 2 hours and then the product was removed. XRD patterns showed that the dominant phase in the product... 

Viewpoints of various interest groups should be addressed in any public service appraisal. Urban public transportation development and services have diverse impacts on users, operators and the community. The impacts can be characterized by a wide range of perspectives including: efficiency, effectiveness, efficacy, economic, social and environmental dimensions. Deployment of quantitative techniques, such as multicriteria decision making methods, would facilitate such a multidimensional analysis and appraisal. The objective of the study summarized herein was to shed some light on the perceived attributes pertinent to the Tehran regular transit service appraisal. The major services include... 

Nowadays anaerobic treatment of wastewater has been gaining more and more popularity. This process is usually used for waste sludge and wastewater with high concentrations of organic pollutants. One bioreactor that uses the anaerobic process to treat wastewater is the Anaerobic Baffled Reactor (ABR). This reactor was studied in the present study. The Anaerobic Baffled Reactor is composed of a series of up flow anaerobic sludge reactors. A simple design, low process cost, low sludge production and the lack of a need for a separator of the gas and sludge are some of the important characteristics of this reactor. Furthermore, ABRs are resistant against temperature and pH and can separate... 

Biodegradation has always been as a proper method for treatment of oil contamination. Accordingly, several investigations have been done by mesophilic bacteria for biodegradation of hydrocarbons while few studies have been conducted about thermophilic bacteria.
There are many factors like high growth rate of thermophilic bacteria and good resistance of enzymes secreted from thermophiles against physical and chemical variations lead to the extensive use of thermophilic bacteria for removal of oil contamination. The important factors should be optimized in order to choose a suitable method for the removal of oil contaminations. Optimal conditions for oil contamination removal by... 

The experimental investigation of biodiesel production stages from microalgae especially biomass production stage was conducted in this thesis. The optimal rate of biomass productivity was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out.
According to the results, the optimal condition for growing of microalgae was obtained with aeration of 6 lit/min with 3% CO2, and CO2 injection regime of 45 sec. injection and 3 min. of stoppage. A rapid... 

Titanium dioxide, due to its specific semiconductive properties, has been a highly investigated material for a variety of applications including gas sensors, hydrogen generation by water photoelectrolysis, photocatalysis, dye-sensitized solar cells and purification of water and air. Several recent studies have indicated that titania nanotubes have improved properties compared to any other form of titania for mentioned application. Titania nanotubes have been produced by a variety of methods including deposition into a template and hydrothermal processes. Anodic oxidation of titanium foil in a fluoride-based solution is one of the best methods to produce of titania nanotube arrays. Highly... 

Nanocomposite films based on low density polyethylene (LDPE), containing of 2, 3, and 4 wt% organoclay (OC) and ethylene vinyl acetate (EVA) copolymer as a new compatibilizer were prepared and characterized using X-ray diffraction, tensile tests, and oxygen permeation measurements. There was no exfoliation or intercalation of the clay layers in the absence of EVA, while an obvious increase in d-spacing was observed when the samples were prepared with EVA present. This issue was reflected in the properties of nanocomposites. The oxygen barrier properties of the OC/EVA/LDPE film were significantly better than those of the OC/LDPE film. The average aspect ratio of clay platelets in... 

This research relates to an improved method for making surfactant esters, especially sorbitan monostearate and tristearate. Sorbitan esters of fatty acid, stearate are derived from a reaction between sorbitan and fatty acid. Sorbitan fatty acid ester called sorbitan ester, are surfactants highly safe to use on human body and are widely used as a food additive in the production process as emulsifiers. Sorbitan esters are well known emulsifiers suitable for use in food, pharmaceutical products as well as many other applications. Despite its simple name, sorbitan ester is complex mixture of molecules. One such technique involves direct esterification of sorbitol or an intramolecular condensate... 

In this work, the recovery of rhenium from ferromolybdenum furnace outgoing dust in semi industrial scale was conducted. The ferromolybdenum furnace outgoing dust contains rhenium as major part and large amounts of molybdenum plus Iron and copper as impurities. An overall flow sheet, consist of leaching, solvent extraction and precipitation methods, was design to recovery and purification of rhenium. Firstly, ferromolybdenum furnace outgoing dust was subjected to leaching treatment by 10 g/L sulfuric as solvent at 85 C. Secondly, solvent extraction method was employed, using LIX984N 10 %vol, to separate copper from rhenium containing solution. The results of MacCab thiele diagram for... 

The accurate assessment of biomarkers likes proteins, hormones or other biomolecules that amount of them changes with state of disease or level of treatment and gives diagnostic information is a difficult duty. In these samples, pathogens exist in small quantity compared to other background molecules. Therefore, appropriate sampling process for concentrating and separating pathogens from the matrix should be developed in order to provide rapid and accurate pathogen detection test. In this thesis design and fabrication of microfluidic biosensors based on the modified nanofibrous membranes were investigated and explained. PES nanofibrous membrane with carboxyl functional groups for covalent... 

Recent studies in nanotechnology field have shown this technology could solve many challenges and needs in oil and gas industry. As yet, many applications of nanoparticles in enhanced oil recovery have been reported. One of the most important applications is wettability alteration due to presence of nanoparticles in injecting fluid, which has recently been studied by several research groups. These studies indicate that, presence of nanoparticles in injecting water would improve oil recovery. However, there is no adequate information about the mechanisms affecting fluid flow in reservoir rock and its mathematical modeling.The aim of this project is to evaluate the effect of injection of... 

The removal of glyphosate, one of the most widely used herbicide, with membrane bioreactor (MBR) was studied. Beside of glyphosate, the synthetic wastewater contained molasses and other salts as nutrient source. The membrane was made from polypropylene and was immersed in the bioreactor. The COD of the feed was adjusted by varying the ratio of glyphosate to molasses. The total COD was 500, 750 and 1000 mg/L. The resulted showed that when the bioreactor coupled with membrane the removal efficiency increased. The increase was attributed to higher concentration of biomass or MLSS in the MBR. The average of MLSS in the MBR was 8500 mg/L while in bioreactor without cell recycling and in batch... 

for decades Cancer has been one of the major causes of death universally. Though extensive efforts in developing new anticancer therapies, they face failures in clinical trials and curing the sick owing to time consuming and expensive preclinical models with poor predictions of drug responses in human. To address this challenge it is crucial to develop preclinical models mimicking the main aspects of a tumor that can provide effective prediction of therapeutic responses. Tumor on chip technology has appeared as a promising approach for providing effective cancer models and reliable preclinical predictions. In this project, collagen was first extracted as the main constituent of the tumor...