Sharif Digital Repository

In this study the performance of the conventional activated sludge and the membrane bioreactor systems were investigated and their operations were compared. . A membrane bioreactor and a conventional activated sludge system which includes one aeration basin and one settling tank were designed and constructed. The feed was synthetic and the BOD:N:P ratio was 100:5:1. In order to starting the systems, the sludge supplied from the municipal wastewater treatment plant and inoculated. Then, the inoculated sludge was adapted to treat the starch wastewater with step by step increasing the feed COD. . The performance of two systems investigated in inlet COD=2500 mg/L and four hydraulic retention... 

Hydrogels are crosslinked hydrophilic polymers that are capable of imbedding large amounts of water or biological fluids usually to equilibrium. Because of their unique properties, these materials have become ubiquitous and indispensable materials in many applications in recent years. Synthetic methods have produced numerous hydrogel materials with excellent properties. However, their nonbiodegradability might pose long-term environmental problems and limit their use. As a consequence, various research groups have put considerable amounts of effort and resources toward development of new absorbent materials from natural polymers such as polysaccharides. In this research, new hydrogel... 

Polysaccharide is important in terms of their environmental interest, scientists have been growing. According to the structural properties of this interesting class of natural polymers, in terms of having chemically active groups on the high density polymer housing provides the possibility That can perform chemical reactions with the new properties of these polymers to give. Starch polysaccharides in the project through a chemical reaction to the structure of a third type of bridge Amen to that using 1HNMR and 13CNMR predicted structure was approved. The modified polysaccharide has catalyst activity. This activity in knovenagel reaction for some aldhydes was used and results were... 

Platelet nanoparticles could dramatically decrease permeability of polymeric film where increase considerably its physical -mechanical properties. Bio based (Biodegradable) polymeric materials such as starch based polymeric films show very weak mechanical and high oxygen and water vapor permeability. Graphene oxide (GO) could increase mechanical properties of starch based polymer where decrease its permeability dramatically. Addition of chitosan also could increase antibacterial and antifungal of films and decrease permeability of films considerably. In this research nanocomposite of Starch/Chitosan/GO films have been prepared by solution method and its morphology, permeability, physical... 

There are so many problems in using of petroleum-based polymers such as their stability in the environment. According to the research carried out on this problem, one of the best ways to overcome this hardship is using of bio-based polymers. The most important bio-based polymer is polylactic acid. The very polymer enjoys the best mechanical properties but it is so expensive that make it impossible to afford. Therefore, in this project, a nano-composite structure of polylactic acid with thermoplastic starch reinforced with nano-particles was produced. After manufacturing, the process of mixture and the best percent for the very mixture for its use in packaging industry were investigated  

The purpose of this project is to design a water-based drilling fluid for use in high-pressure and high-pressure conditions (Deep Drilling). This goal is usually achieved by adding the resistant polymers to the ambient conditions (temperature stability) to the drilling fluid (here the blue base fluid), and then the rheological properties of the fluid are studied. The stability of the rheological properties of the fluid in high temperature and high pressure conditions is not constant. In this situation, a sequence of events occurs, for example, decreases with increasing viscosity and turbulence, and hence the reduction of drilling fractures and the efficiency of the bottom of the well is...