Sharif Digital Repository

Chlorinated hydrocarbons such as trichloroethylene form a kind of dense non-aqueous phase liquid contaminants in groundwater and soil that are so difficult to remediate. In recent years, many field research has been demonstrated application of nano scale zero valent iron can degrade these contaminants.
In this research, nZVI particle synthesized by liquid phase reduction method. Nickel (25%wt ) has been added to increase the reduction rate and also reduce intermediate pollutions. However, the combination of a noble metal to nZVI, leads to more rapid oxidation and tendency to agglomeration. So nZVI particles coated by applying a water soluble-starch solution (0.4%wt) as a stabilizer. The... 

Inthis thesis, we provide a reduced multiple linear approximationfornonlinear systems. This approximationis a weighted summation of reduced order models thatapproximates the states or output(s) of the nonlinear system. It can be used inreal-time control instead of high-ordernonlinear models in order toreduce thecomputational cost. The reduction of computation cost is claimed qualitatively, based on the linearity of the approximation and its less order compared to the original model. To form amultiple modelapproximation eachlinearmodelis obtained from linearization atanoperating point. Then,each model is reduced byalinearreduction method. We used truncation and balanced residualization... 

Today, considering the structural health monitoring system is approximately essential for aerospace structure due to more safety and reduction of maintenance costs. In this manner, aircraft designers and manufactures have recently attempted to usage of the monitoring system on their new products to maintain the superirority of them among the competitors. Furtheremore, installation of these systems on the aircraft will also becom one of the requirements of the aviation regulation in near future which must be complied.The lap joints are one of the major and inevitable components of the metallic airframe structure and the multisite damage such as fatigue cracks are the high probable damages... 

In recent years, significant interest has been attracted towards using directional antennae in wireless and sensor networks due to it’s decreased energy consumption, increased security and decreased radio wave overlapping. Substituting omni-directional antennae with directional antennae should be performed in a way that not only guarantees connectivity, but also minimizes radius and latency in network nodes. The problem is not polynomially solvable in general and effort has been made in recent years to present approximation algorithms to solve this problem. The approximation algorithms have been made possible using unit disk
graphs, Euclidean minimum spanning trees, grouping of... 

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...