Sharif Digital Repository

In the recent years, nanophotocatalytic process for E. coli inactivation has become considerable choice for water treatment. Having suitable catalytic characterizations, nanophotocatalysis could be considered as an alternative to current E. coli disinfections methods.
In this study, antibacterial effect of Fe-Cd/TiO2 (TiO2 doped with Fe and Cd) under visible light was reported for the first time. The Results show that by comparing Fe-Cd/TiO2 with commercial TiO2 (P25 Degussa), bactericidal efficiency of this codoped photocatalysis under visible light is high and effective. Indeed, Nanoparticle of Fe-Cd/TiO2 disinfects E. coli (cell density: 107 CFU/ml) almost completely within 55 min... 

In massive construction projects such as construction of high-rise buildings, bridges, and concrete pavements, engineers strive to set up an on-site concrete batching plant; however in most cases, due to the lack of space availability, it is not possible to do so.Therefore, in order to procure high quality concrete, ready mixed concrete suppliers are sought. The notable management point is the distance between the ready mixed concrete plant and the construction site. The investigations show that the increased hauling time of ready-mixed concrete could significantly influence the quality of produced concrete. This issue is of more importance in the urban areas (e.g Tehran) as the traffic... 

Queue is crucial in new atmosphere of business. Firms and people see the dark side of this phenomenon. Investigation on The other side of queue is our main purpose of this study. Examining the relationship between queue and Perceived Quality, Price, Sacrifice, Value, and willingness to buy that make our conceptual framework and hypotheses is our primary objective.Questionnaire designed for evaluating construct. For each construct, standard scale was used. A survey was conducted in Iranian universities. The final sample includes 295 respondents. Regression analyses were performed.Results show significant relationship between our construct that confirm the other side of queue. Results show... 

Concentrations of air pollutants emitted by motor vehicles in traffic tunnels, due to low access of tunnels to Open space increases rapidly. Increasing the tunnel pollutant concentration, decreases tunnel air quality level which is very dangerous for human health. Thus study of traffic tunnel air pollution concentration and dispersion is important for offering control strategies in these spaces. This investigation has been tried to study vehicular pollutants emission and dispersion inside traffic tunnel by data collection that involves traffic, meteorology and air pollutants characteristics in a urban tunnel. So data collection was carried out in the Resalat tunnel located in urban... 

In this thesis, photocatalytic oxidation as a potential method for the treatment of organic environmental contaminants is deeply investigated. While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low-levels of the pollutants such as Dibenzothiophene (DBT) and 2-Nitrophenol (2-NP) are occasionally reported. In the present work, Lanthanide / Polyethylene glycol -modified TiO2 (La/PEG/TiO2) and Fe,Cu,S/TiO2 have been successfully synthesized by a sol–gel method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission... 

Paclitaxel is used as a drug against breast and ovarian cancers. Although paclitaxel has high biologic activity, it has very pour solubility in water like some other drugs. Since drugs should be solved in water to be absorbed by the body, for absorb enhancement, we should use carriers which includes both polar and non polar sites. eta-Cyclodextrin which has this feature is capable for producing inclusion complex in its hydrophobic pores with non polar materials. In this project by adding polymeric polyacrylamide branches on beta-Cyclodextrin, polymeric nano structure has been developed to enhance water solubility in comparison with pure beta-Cyclodextrin. Study on producing polymeric nano... 

In this research, fabrication of a mediator free nano-biosensor for the detection of cyanide has been studied. This biosensor utilizes 75 nm diameter (nano) ZnO particles synthesized with sol- gel method for modification and immobilization of Horseradish peroxidase (HRP). Cyanide plays inhibitory role in decomposition of H2O2 while HRP plays catalyst role in this reaction. Cyanide inhibits enzyme activity thorough binding with enzyme active sites and result in decreasing electrical current in electrochemical decomposition of H2O2. Amperometery response of biosensor shows linear relation between inhibition percent and cyanide concentration in range of 3µM - 24µM with detection limit of 0.62µM... 

MOFs are new class of materials that are used in different scientific fields because of their hybrid structure. In this project, focused on two specific applications, and aim is synthesis of a nanostructure which has antibacterial and photocatalytic activity. ZIF-8 because of its chemical and physical stability has been studied. For improving antibacterial influence and photocatalytic activity, silver nanoparticles are added to the structure. Magnetic nanoparticles covered by silica were used as core to facilitate separation process, ZIF-8 structure was constructed as shell on SiO2@Fe2O3 nano spheres. Magnetic nanoparticles improving stability of ZIF-8 in aqueous solutions. Synthetic nano... 

In the world of today, the high rate of change, instability and uncertainty leave organizations under the constant effect of crises and unforeseen events. The prediction, prevention and control of crises alongside sustained performance and stability are now vital to the survival of organizations. The COVID-19 pandemic has created innumerable challenges for many businesses in Iran, including Small and Midsize Enterprises involved with health tourism, and has placed their subsistence at risk. The concept of Organizational mindfulness can help organizations avert crises and unexpected incidents, while rapidly bringing such events under control and mitigating the associated damage, should they... 

Brand perceptual mapping is a way to display the market structure in a particular industry. In the past, marketing managers relied on questionnaires and focus-groups' data to map the market structure and extract insights from it. These methods are expensive, time-consuming, and not generalizable due to the small sample size. With the expansion of social media, new techniques have been introduced that can map the market structure by analyzing user-generated content on social media. Currently, methods used for this task are automated methods based on the bag-of-word model, which ignores the meaning of words and sentences and needs big datasets. In this research, using language models and... 

Brand perceptual mapping is a way to display the market structure in a particular industry. In the past, marketing managers relied on questionnaires and focus-groups' data to map the market structure and extract insights from it. These methods are expensive, time-consuming, and not generalizable due to the small sample size. With the expansion of social media, new techniques have been introduced that can map the market structure by analyzing user-generated content on social media. Currently, methods used for this task are automated methods based on the bag-of-word model, which ignores the meaning of words and sentences and needs big datasets. In this research, using language models and... 

The partition coefficients of L-Lysine HCL were measured in polymer-salt aqueous two-phase systems. These systems contain polyethylene glycol with nominal molecular weight of 4000 or 10000 and two different salts (di-potassium hydrogen phosphate or tri-sodium citrate 5,5-hydrate). The experimental data were obtained at temperatures 293.15, 298.15 and 303.15 K. The effects of temperature, pH, polymer and salt concentrations, polymer molecular weight and salt type on the partitioning of L-Lysine HCL were also studied. The results showed that salt concentration has a significant effect on the partition coefficient while temperature has a low effect. The experimental partition coefficients of... 

Dense underflows are continuous currents that move down-slope due to their density being heavier than that of the ambient water. This difference between the dense fluid and environment fluid can be due to temperature difference, chemical materials, solved materials or suspend solid particles. In these currents, the effect of buoyancy force is produced by this difference density. In this research, many experiments performed in different flow rates, slopes and concentrations to understand the current structure and turbulence specification of the salt solution density currents and particle-laden density currents. Acoustic Doppler Velocimeter is used to measure the velocity fluctuations. The... 

In this research, the partitioning of Penicillin G-Acylase in aqueous two-phase systems (ATPS) containing poly ethylene glycol (PEG) 20000 or 35000 and potassium di-hydrogen phosphate (KH2PO4) or sodium citrate (C6H5Na3O7.5H2O) is measured at three temperature (301.2, 307.2 and 310.2) K. The effects of temperature, polymer molecular weight, polymer and salt concentrations on partitioning of Penicillin G in the aqueous two-phase systems are studied. The experimental data showed that composition of salt has a large effect on partitioning of Penicillin G in ATPS and temperature of system has small effect on the partitioning. The modified local composition model was used to obtain the activity... 

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... 

This project surveys bioregeneration of granular activated carbons contaminated with phenolic compounds. To carry out this survey, the procedure of phenol absorption on the surface of activated carbon was studied and their adsorption isotherms were calculated. In the first step, newly activated carbon was contaminated with phenol solution and optimum amount of carbon in phenol elimination was 0.5g. Then, the effect of time contact on phenol elimination was studied and eventually 1 hour of time contact was determined as the equilibrium time of phenol adsorption. In the second step, kinetics of adsorption of phenol and different stages of adsorption were studied. The results of this study... 

In this project an enzymatic peroxidase biosensor based on two naono structured material 1-Polyaniline nananofibers 2-Polyethylene glycol-Poly citric acid copolymer was studied for phenol detection.Polyaniline nanofibers and poly ethylene glycol-poly citric acid copolymer were synthetized by chemical polymerization.Electrochemical behaviors of these biosensors were studied using cyclic voltammetry (CV) and amperometric techniques. The amperometric response of the coated electrodes is highly stable with 92% of the initial activity remaining after 5 determinations. These phenol biosensors show an oxidation peak at 0.55V. The amperometric response for phenol biosensor based on Polyaniline... 

Nowadays with the extension of industry and factories as well as different kinds of plants, a wide range of pollution and circumference hazardous has been entered to the people`s life. Industrial wastewater has been always a threat for health of our environment and efforts for reducing its dangerous effects are still under studies. Dairy wastewater is one of the main branches of food industrial pollutions and it has been studied in this specific project. The goal was to reduce the Chemical Oxygen Demands (COD) of dairy wastewater with oxidation of Titanium Dioxide Nanophotocatalyst oxidation under UV irradiation. Among the various methods for synthesizing of this Nanophotocatalyst, the... 

In this research, Response Surface Methodology was applied to study the effects of Na-Montmorillonite and glycerol on some functional properties of corn starch films. Films were prepared by casting method according to central composite design. No antimicrobial activities were observed against Escherichia coli and Staphylococcus aureus. The minimum of hydrophilicity and the maximum of tensile strength were obtained by maximization of clay and minimization of plasticizer in the considered range, which resulted in minimum transparency. Biodegradation of corn starch/glycerol/Na-MMT nanocomposites by soil burial according to ASTM D6400 and enzymatic degradation tests were carried out for up to 6... 

In First part, the electrophoretic deposition method was utilized to immobilize TiO2 particles on stainless steel substrates. In addition, for the first time, statistics-based experimental design using response surface methodology (RSM) was employed to investigate the effect of four key coating parameters (i.e. applied voltage, calcination temperature, photocatalyst weight percentage, and deposition time) on the photocatalytic degradation. Analysis of variance revealed that the proposed model was adequate. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to evaluate the effects of the parameters on degradation efficiency. The optimum applied voltage, calcination...