Sharif Digital Repository

In this research, carbon nanotubes (CNTs) and CNT coated by titanium dioxide (TiO2) were used as adsorbents for desulfurization. Photocatalytic oxidation by titanium dioxide Degussa P-25 nanoparticles (as photocatalyst) immobilized on a porous and low-density support called “perlite” and CNT/TiO2 was perused. TiO2-coatings were prepared by liquid phase deposition method.This is a wet process for the formation of metal oxide thin films on substrates. The coating of nanotubes with TiO2 was confirmed by IR and EDAX and morphological properties were observed by SEM analysis.The physical properties of adsorbents were determine using BET.Dibenzothiophene (DBT)dissolved in acetonitrile was used as... 

In recent year's acrylamide as a suspected substance for tumor growth has been studied. In some researches this topic is mentioned that acrylamide is produced by the reaction of asparagine and natural sugars. This reaction takes place only at very high temperatures during the heating process. The maximum amount of this substance is determined in fried potato products. The purpose of this study was determined to remove and reduce acrylamide formation during frying of potato. Acrylamide production when it was blanching and when it was dipped in the enzyme solution of asparaginase was examined. When potato pieces were placed in a commercial enzyme solution 200 lU/ml, acrylamide formation was... 

β-galactosidase enzyme is immobilized from Kluyveromyces lactis by Microencapsulation method in various compositions of sodium alginate and Carboxymethyl cellulose. Optimum stabilization was gained at 1.85% sodium alginate, 0.9% carboxymethyl cellulose and 2% calcium chloride through applying Surface response methodology. Yield of immobilization and activity was 54.94% and 65.27%. variation of yield of immobilization versus alginate concentration was a quadratic curve with the maximum. When alginate's concentrations is low, the cavities diameter is great, so the enzyme leaks from capsule while immobilizing. At high concentrations of alginate, despite the smaller cavities, immobilization... 

Photocatalytic degradation is one of the developing modern and effective methods for decontamination of hazardous pollutants of chemical industrial wastewater. This method has several advantages including the possibility of using free and sustainable energy of sun. However, it is still needed to active photocatalysts under solar light and also the enhancement and optimization of operating parameters, and consequently, these topics are selected as goals of the present thesis. Accordingly in this research, first, to obtain a photocatalyst that is highly efficient (especially under visible and solar light), multi-doping and polyethylene glycol (PEG) were used and for the first time,... 

Penicillin G Acylase is the key enzyme in producing semi-synthetic antibiotics such as Ampicillin and Amoxicillin. In this study, we used E.coli ATCC 11105 in order to produce it. This enzyme was an intracellular one which was produced under suitable conditions. Crude enzyme was released after cell disruption by ultrasonic waves (sonication method) and was partially purified by ammonium sulphate precipitation. Immobilization is investigated at different pHs around the iso-electric pH of Penicillin G Asylase enzyme. Therefore, optimum pH and optimum concentration of ammonium sulphate cuts were determined. Also immobilization process of this enzyme was studied on chitosan polymer, activated by... 

In this study, Pseudomonas aeruginosa BBRC-10036 was used for lipase production. The organism secreted the enzyme extracellulary. First of all, effect of initial pH of the culture broth on lipase activity was studied in order to determine the optimum condition for lipase production. After production, this enzyme must be separated from culture and after that the enzyme must be purified for using in analysis and industry. Different methods are used for purification of the enzyme. In this research, first precipitation was used and then this lipase has been purified by Ion exchange Chromatography leading to 2.33- fold purification and 11.47% recovery. In precipitation by acetone, maximum... 

Xanthan gum is a water-soluble exo-polysaccharide. It is produced industrially from carbon sources by fermentation using the gram-negative bacterium Xanthomonas campestris. There have been various attempts to produce xanthan gum by fermentation method using bacteria and yeast by using various cheap raw materials. In this study the cultural conditions for xanthan gum production by Xanthomonas campestris were investigated and optimized by response surface methodology, to maximize cell and xanthan production in batch experiments using YM broth without pH control. The individual and interactive effects of three independent variables (carbon source concentration (40-80 g/l), nitrogen source... 

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... 

In this project we focused on Ultrasonic waves as novel, effective and well-controllable means for cell wall disruption and disintegration to provide faster and more complete penetration of solvent into cellular materials and improve sugar mass transfer and extraction from sugarcane and sugar beet. Impact of frequency, temperature, power density and reactor shape on Ultrasonic wave efficiency in extraction process has been investigated and the result was utilized to design a semi-pilot reactor. In the optimum situation, sucrose extraction from sugarcane improved to 4.51 gr/100 ml H2O that had a significant increasing from 2.1 gr/100 ml H2O extraction in thermal only process at 70 °C. Optimum... 

Xylitol is a sugar alcohol or polyol that has been used as a food additive and sweetening agent due to Its high sweetening power, anti-cariogenic properties and possibilities for use in diabetic food products, makes xylitol an attractive sucrose substitute in a wide variety of foods and beverages. Xylitol is a five carbon polyol or pentitol obtained by the hydrogenation of xylose. xylitol could be produced from xylose in rice seed coats medium by Saccharomyces cerevisiae. For xylitol production, S.cerevisiae was grown in preculture medium at 30°C and agitated at 120 rpm on a rotary platform shaker. The cells were harvested after 20hr, were centrifuged and transferred to the production... 

In recent year's acrylamide as a suspected substance for tumor growth has been studied. In some researches this topic is mentioned that acrylamide is produced by the reaction of asparagine and natural sugars. This reaction takes place only at very high temperatures during the heating process. The maximum amount of this substance is determined in fried potato products. In this study, a response surface methodology (RSM) 5-level-3-factor face centre central-composite design (FCCCD) was applied to envestigate the effects of asparaginase (300-900 U/kg of flour), baking temperature (230-280 °c) and baking time (13-16 min) on acrylamide (AA) formation in yeast-leavened wheat bread and... 

Honey as a food product with plant origin that nearly ninety percent of its dry weight is composed of sugars (mostly fructose and glucose) which has many food and pharmaceutical properties. So honey quality strongly depends on bees feeding practices. For this reason common indexes is defined generally are on the basis of hony composition, for example fructose and reducing sugar portion must be at least thirty and sixty-five percent respectively of total weight or sucrose percent must be utmost five and otherwise puts into question honey quality. To check the quality of five honey samples taken from the market, indexes such as water content, sugar composition(fructose, reducing and total... 

Vitamin C is one of the essential ingredients for the survival of human beings, animals and plants. This vitamin is an ester that in its structure there is a cyclic ester, an alkene Factor (C = C) and four hydroxyl factor (OH). This vitamin is a white solid, water-soluble and non-toxic that exists in many fruits, especially citrus. Its presence in the diet of human resistance them against infections increases. The main factor causing acidic property in vitamin C is the presence of OH groups attached to the alkene. Various forms of vitamin C exists in pharmaceutical collection of European countries. Since the tablet form because of the many advantages including being economical compared with... 

Conjugated linoleic acid (CLA), a mixture of positional and geometrical isomers of linoleic acid with conjugated double bonds, has gained considerable attention because of its anticarcinogenic and obesity treatment properties. The most biologically active CLA isomers are 9c, 11t-18:2 and 10t, 12c-18:2. Natural sources of CLA are fat of meat and dairy products derived from ruminant animals. About 3 grams of CLA per day is necessary to provide human health needs, but each person receives about 10% of this value from natural resources, thus production of CLA as a dietary supplement is necessary. CLA is produced from biological and chemical methods but because of high yield of chemical... 

Theanine is a non-protein amino acid which was first isolated from tea plant leaves (Camellia sinensis) and also found in a mushroom named Xerocomus badius and some other Camellia species such as C.japonica and C.sasanqua. Theanine comprises about 50% of amino acids in tea and 1-2% of dry weight of tea leaves. It contributes to the umami taste and unique flavor to tea infusion and has many physiological and pharmaceutical effects such as anti-tumor and anti-cancer activity, neuroprotection, antihypertensive, relaxation, increased focus and anti-obesity effects. So this compound is essential for human body but is not synthesized in it and should be administrated orally. In recent years, study... 

The treatment of water effluent from alcohol industries is among the most challenging industrial wastewater treatments. The challenge mainly arises from the high capacity of organic compounds allowing the growth of microorganisms and pollutants. Brown color of the wastewater also contributes to this phenomenon; it absorbs more sunlight which then reduces the oxygenation of water and thus adversely affecting the aquatic life. Moreover, the acidity of the wastewater decreases the pH level of agricultural soils, so its quality Thus, distillery wastewater, without any treatment can pose a serious threat to the environment. In our study, we investigate the decolorization of molasses wastewater... 

In recent years, much attention has been paid to the preparation of nanoparticles as carriers for drug delivery. Nanoparticle carriers, by changing the pharmacokinetic properties of the drug, improve the function of the drug and reduce its side effects. In the manufacture of nanoparticles, various materials such as polymers, metal particles, lipids, etc. are used to transfer the drugs, which can produce a different shape and size of the particles depending on their production method. The purpose of this project is the synthesis of liposomal nanoparticles (as nano-carriers) to load an antibiotic (Eucalyptus oil) and study the release of the encapsulated drug in the simulated environment of... 

Probiotics are defined as essential live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. In order to provide health benefits for probiotic bacteria it has been recommended that they must be present at a minimum level of 106 CFU/g of food product or 107 CFU/g at point of delivery or be eaten in sufficient amounts to yield a daily intake of 108 CFU. Several studies have shown that certain strain of lactic acid bacteria, such as Bifidobacterium bifidum and Lactobacillus acidophilus prevent some diseases linked to the gastro-intestinal tract. however, many reports have demonstrated their poor survival and stability. Their survival in the... 

A labeling of a graph is a bijection of edges in graph G to the set {1,2,…, m}. A labeling is antimagic if for any distinct vertices u and v, the sum of the labels on edges incident to u is different from the sum of the labels on edges incident to v. We say a graph is antimagic if it has an antimagic labeling.. In 1990, Hartsfield and Ringel conjectured that every connected graph other than K2 are Antimagic.In this thesis, we show that each graph with at least two degrees can be called Antimagic. We prove this conjecture for regular graphs of odd degree. and then it will be shown that Cartesian graphs have the property of Antimagic Labeling. Finally, we purpose a novel method for k-th powers...