Sharif Digital Repository

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... 

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... 

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... 

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... 

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 present M.Sc. thesis consists of two sections including the static calculation and neutron noise calculation in rectangular and hexagonal geometries. The multi-group, two dimensional neutron diffusion equations and corresponding adjoint equations are solved in the static calculation. The spatial discretization of equations is based on Average Current Nodal Expansion Method (ACNEM). Size of nodes is the same size of the fuel assemblies in modeling both of rectangular and hexagonal geometries. The results are benchmarked against the valid results for BIBLIS-2D and IAEA-2D benchmark problems. In the second section, neutron noise calculations are performed for two types of noise sources,... 

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... 

Magnetic resonance imaging (MRI) is a highly efficient method that can provide acceptable contrast between soft tissues. But the big disadvantage of this method is that its acquisition is slow. To find the reason of being time-consuming should the procedure be surveyed. In the magnetic resonance imaging, location information obtained using phase and frequency encoding gradients. So the output is matrix of image data in the frequency domain, which is called k space. For the formation of the k space phase, need to apply gradients several times and this is the main reason of dullness of the system. Therefore, in this project using software methods try to reduce the scan time as possible. Among... 

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... 

The present ph.D. thesis consists of three sections including the static calculation, neutron noise calculation and neutron noise source unfolding in VVER-1000 reactor core. The multi-group, two dimensional neutron diffusion equations and corresponding adjoint equations are solved in the static calculation. The spatial discretization of equations is based on Galerkin Finite Element Method (GFEM) using unstructured triangle elements generated by Gambit software. The static calculation is performed for both linear and quadratic approximations of shape function; baesd on which results are compared. Using power iteration method for the static calculation, the neutron and adjoint fluxes with the... 

High purity Germanium (HPGe) detector is a sub branch of semiconductor detectors which has very good resolution, very little dead time, able tobuild in large dimensions and suitable for any condition that it is using in vast fields from space investigation to radiation therapy. this detector is usually used to detecting gamma radiations furthermore the best resolution can be attained with decreasing leakage current. for analyzing about operation of the HPGe detector, it needs to initiate a model of this detector. in this studing has been used modelGEM-15190,POP-TOP which is built by ortec company. for initiating, it was used liquid nitrogen and accessory equipments like high voltage supply,... 

The analysis of gamma-ray spectra of low resolution detectors is difficult and sometimes impossible, as a result of photo peak’s overlapping. The usual methods of radiation spectra analysis based on fitting of peaks to mathematical curves or detecting of peaks with numerical calculation, are valid for high resolution detectors. However these methods are less successful for lower resolution detectors such as the common scintillators. The wide peaks in the spectrum maybe overlap and make it difficult to analysis. To solve this problem, we test here a method, based on the use of the artificial neural network. At first spectra of elements are converted to the patterns which are suitable for the... 

Radiation detection techniques have important applications including prompt gamma neutron activation analysis (PGNAA), radiotherapy dose measurement, medical imaging and homeland security. Pulse height distribution is also a useful parameter in Radionuclide identification. Gamma ray spectroscopy analysis is a common technique in measuring of radiation field to identify the radioactive source.
Probabilistic methods are commonly used for numerical simulation of Pulse height distribution. In Monte Carlo methods, each history is individually tracked and details of interactions are available. Using the Monte Carlo methods for calculation of pulse height distribution leads to more real... 

Microrobots design and manufacturing has been one of interesting fields in robotics in recent decades. They have been designed in various types so far. In this paper a two-leg microrobot is simulated and controlled by using LuGre friction model.
The proposed microrobot is driven by a piezoelectric actuator mounted between centers of two legs. The piezoelectric is actuated by a frequency near the natural frequency of the robot. The nonlinear dynamical equations of the system are obtained considering LuGre friction model. To control the system, the equations of motion are linearized using feedback linearization method. Then a stabilizing control law is designed and the robot model is... 

Neutron fluctuations in both low and high power reactors provide important information about the system. The origins of these fluctuations are different in both regimes. In low power the branching process is the reason of these fluctuations. But the random nature of technological processes such as boiling in the reactors cooling and mechanical structure vibrating such as control rod and fuel rod created the neutron noise. Mathematical descriptions and applications of neutron noise for each mode are different. In common mode, fluctuations in the neutron detection system, determine some parameters and determin the start abnormality in system. In this study the spatial dependence of the cross... 

Localization of a neutron point source using a designed computer program namely “MCMC-MATURE” is performed. The computer program analyses several detector responses in some certain media by Markov Chain Monte Carlo (MCMC) method and a new iteration algorithm. Identification of the possible regions of source position would be found by analyzing the initial fluxes generated by mesh tally of MCNPX computer code. The designed computer program is capable to generate the flux between detectors. “Regular-Sequential”, “Irregular-Sequential” and “Non-Sequential” are three methods used for sampling the generated random number in two dimensions. Each sample multiplied by a sampling function and lead to... 

In this project, the final goal is to create a team consisting of a UGV and a quadrotor capable of relative tracking and coordinated landing, with focus on quadrotor control. What we mean by cooperative control in this project is control of quadrotor for the purpose of cooperation with a UGV; This should not be mistaken with another sense of cooperative control in which the control algorithms are developed for both of the robots or are based on the interactive dynamics of the robots.In order to accomplish this goal, an experimental testbed consisting of a quadrotor and a UGV capable of communication and data exchange was developed as a first step. The quadrotor was constructed using...