Sharif Digital Repository

In this research performance of microbial fuel cells (MFCs) in continuous flow mode was studied. Different anodic chambers were tested and it was found that granular activated carbons (GACs) produced the highest power density (1228 mW/m3) in comparison with multiple anodes (731 mW/m3), single anode (294 mW/m3) and polymeric packings (40 mW/m3). It was also shown that in a plug-anodic chamber (PAC) the power output is reduced by reducing agitation of anodic volume. Adding more GACs to anodic chamber results in power increase, however by increasing occupied volume from 80% to 100% the power increase was negligible in result of cathodic reactions limitations. Feed flowrate was increased from... 

An impedimetric human papilloma virus (HPV) DNA biosensor based on gold nanotubes (AuNTs) in label free detection was materialized. The AuNTs decorated nanoporous polycarbonate (AuNTs-PC) template as biosensor electrode was fabricated by electrodeposition method. The single strand DNA (ss-DNA) probe was covalently immobilized onto the AuNTs-PC electrode. The hybridization of target sequences with the ss-DNA probe was observed by the electrochemical impedance spectroscopy (EIS). The biosensor showed high selectivity and could differentiate between the complementary, mismatch and non-complementary DNA sequences. The EIS measurements were matched to Randle's equivalent circuit. The... 

By consideration of increasing demands to use implants and efforts to get technical knowledge and localization of this implants, considerable research in this field is needed. Therefore, presentation of a coating which is able to provide parameters needed for an acceptable implant is the aim of this study. In this direction, modification of surface of metallic implants in order to achieve nanotubes of titanium oxide, with the purpose of providing biocompatibility was done. On the other hand, because chronic infection of the implant’s surrounding is one of the main important reasons in rejection of implants, 〖TiO〗_2 nanotubes as a drug carrier were used in order to solve this problem. So,... 

The use of dental implants has grown considerably in recent years in Iran but this piece is the industrial imported parts that are not yet produced in Iran. So the main purpose of this research was to fabricate a dental implant from Ti-6Al-4V alloy by CNC machining techniques. On the other hand, the poor bonding strength of bioactive coatings and low cell growth on the surface of uncoated implants are the common problems in the use of dental implants. So another aim of this study was to investigate the effect of Nanoscale surface topography and nanostructured coatings on the surface modification of titanium implant in order to improve Osseointegration and the bonding strength of bioactive... 

According to human needs and in line with the development of advanced technologies, different biomedical Engineering fields like hard tissue implants are growing rapidly. Despite significant biotechnology Developments in recent years, some problems to the recognition of implants related osseointegration phenomena persist. The deficient osseointegration and implant-associated infections are key issues for the long-term clinical success of titanium and titanium alloy implants, while development of multifunctional surfaces that can simultaneously overcome these problems remains highly challenging. Therefore, the ultimate goal of this paper was to improve bone cell attachment and simultaneously... 

In this project, energy in form of electricity and hydrogen was produced in microbial fuel cell and microbial electrolysis cell respectively. For reducing costs, a stainless steel mesh with graphite coating was used as anode electode. Also for increasing efficiency, anode was positioned in cells in a spiral mode. Efficiency of cells was investigated in batch and continuous mode. In this research, dairy wastewater was used as substrate.This wastewater not only has severe emissions, but also is high energy content. In the field of dairy wastewater treatment and hydrogen production in an microbial electrolysis cell wasn’t observed any article.At the first, wastewater was treated in two... 

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... 

Although much progress has been made in eliminating, conserving, and reducing migration and emissions of radioactive materials, the risk of radioactive material release into the environment is still one of the most important hazards in the use of nuclear energy. In this study, graphene compounds have been used as adsorbents for the removal of radioactive materials due to their high level, cost-effectiveness and simplicity of the synthesis process of various composites. In this regard, the removal of strontium and cobalt by graphene compounds has been investigated. Magnetite nanoparticles were anchored on the surface of graphene by sol-gel method and adsorption in batch mode was investigated.... 

Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake... 

In the present work,the effect of solidification rate on the electrochemical behavior of copperanodes of Sarcheshmeh copper complex has been studied.Inthis regard, three cylindrical coppers pecimens with different solidificationrates casted into water-cooled metal mold (A specimen), metal mold (B specimen) and sand mold (C specimen). Cylinders for microstructural and electrochemical investigation, alongthickness dividedinto several specimens. To investigate themicrostructure of the specimens, opticalmicroscopyand scanning electron microscopy(SEM)were used. ICP testhasbeen usedforelemental analysis of each specimen; and eventuallytoinvestigate theelectrochemical behavior ofeach of... 

The usages of Autonomous Underwater Vehicles (AUV) are limited due to the lack of suitable portable energy sources. Researches show that chargeable batteries and fuel cells are the most appropriate energy source for AUVs in near future. The main purpose of thesis is the modeling and obtaining the governing equations for Aluminum/Air batteries containing seawater, the so-called semi fuel cell. The steady state governing equations include Navier-Stocks equations (Hydraulic-Boundary layer), chemical ionic species mass balance at boundary layer velocity field, electrochemical equations in the electrolyte and the electrode surface, equations of motion of the hydrogen bubbles and equations for the... 

Li-ion batteries have been widely applied as power sources for portable electronic devices. Recently, Li-ion batteries are considered as the most promising energy storage technology for electric vehicle applications however, fundamental improvements are needed. TiO2 (B) is attractive candidate for anodes in rechargeable Li-ion batteries, due to their low cost, non-toxicity and favorable channel structure for fast lithium mobility. It is predicted that synthesis of doped nanostructure of this material, through reducing the diffusion pathway and formation of crystal defects, will increase the capacity of TiO2(B). In this investigation, Co and V doped TiO2(B) nanowires are synthesized by... 

The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of...