Sharif Digital Repository

Surfactants are widely used in enhancing oil recovery. But application of worm-like micelles which seem to be a perfect candidate for enhancing heavy oil recovery have been less studied despite their significant ability in reducing interfacial tension and their high viscosity. This research consists of three parts. In the first part, the kinetic and equilibrium adsorption of surfactant on reservoir rock is experimentally investigated, and its appropriate kinetic and equilibrium adsorption model is specified. According to the adsorption models, the pseudo second order kintic coefficient of adsorption is proved to have a linear relationship with concentration, so its value at different... 

Enzymes are biological catalysts that reduce the activation energy of a reaction in a short time and thus increase the speed of the reaction. The most common enzymes used in various industries, including the detergent industry, are lipases, amylases, celluloses, and proteases. Proteases are one of the most important industrial enzymes. The performance of enzymes is affected by the durability of their activity in long-term storage. Therefore, using a technique that can maintain the activity of enzymes, under storage and usage conditions, is an essential step in making a product containing enzymes. Stabilization-immobilization operation is one of the important downstream processes in... 

Enzymes are an important part of detergents, they reduce the activation energy of the reaction and thus increase the efficiency of the process. Protease enzyme is one of the most common enzymes in detergents. Bacillus strain is the most important strain in the production of this enzyme and among the species of Bacillus, Bacillus subtilis is the most used. Bacillus subtilis is a gram-positive, rod-shaped bacterium. This bacterium is considered a non-pathogenic cell that has the ability to form spores and prevent death and damage in harsh conditions. In this study, CRISPR system was used to modify the genome of Bacillus subtilis ATCC 6633 in order to increase alkaline protease. To increase the... 

In this study, electrochemical oxygen reduction reaction (ORR) was studied on Cu, Pd, Rh, Pd-Cu and Rh-Cu alloys in alkaline solution. Pd-Cu and Rh-Cu alloys were prepared by electrochemical methods. On copper electrode it is found that direct oxygen reduction is accompanied by the electrochemical reductions of copper oxides. Also, mechanism and kinetics of reaction change as the amount of copper oxides increase on the surface. For electrodeposited alloys, it is indicated that the reactivity of Pd-Cu and Rh-Cu alloys toward oxygen reduction is higher than pure Pd and pure Rh. The maximum reactivity among Pd-Cu alloys is related to the sample with 24.5% copper content while the maximum... 

Oil reservoir Protection and production optimization requires the proper use of EOR methods. One of the conventional methods of EOR is chemical flooding (for example polymer, alkaline – Polymer, Nano - Polymer and Alkaline - Nano – Polymer flooding) which used for controlling mobility ratio of fluid within a reservoir, altering surface tension between fluids, and change reservoir wettability. On the other hand prediction of oil production in reservoirs during chemical injection processis impossible without having two-phase relative permeability functions and meanwhile, data from the experimental results of these functions are limited.In this study, effect of polymer type and concentration in... 

Heavy oil reservoirs include a major part of the world’s oil reservoirs. Therefore consideration to their enhanced oil recovery (EOR) aspects has a great importance. In heavy oil reservoirs secondary and tertiary EOR methods, have an insignificant effect on oil recovery and so we’d better to use chemical methods to improve mobility and oil recovery. One of the appropriate EOR methods which has attracted a lot of attention is alkaline – surfactant – polymer (ASP) flooding which has a considerable impact on EOR from heavy oil reservoirs. In this EOR method, the low concentration of surfactant in the injecting fluid, results in a low or ultra-low interfacial tension (IFT) between residual oil... 

Heavy oil reservoirs contain huge amount of initial oil in place in the world. Thus, enhancement of their production attracts lots of attention. Primary and secondary oil recovery methods have just little effects on the production of these reservoirs, thus, using innovative chemical methods which lead them to increase their mobility is recommended to improve their oil recovery efficiency. One of these proper and novel methods which has been established recently to enhance oil recovery is ASP1 flooding that can significantly increase oil recovery from petroleum heavy oil reservoirs. In addition, considerable numbers of reservoirs especially heavy oil reservoirs are fractured reservoirs. In... 

One of the suitable methods in EOR processes is miscible and immiscible gas injection. By gas injection, it is possible to replace all the oil, which is in contact with the gas. However, reservoir heterogeneity, low density, and low viscosity of gas result in problems such as gravity segregation, and fingering and consequently the gas reach the production well without any significant contact with reservoir oil. A way to deal with this problem is gas injection in the form of foam. In fact, gas injection in this manner increases the oil production by decreasing gas mobility and the negative effects of reservoir heterogeneity on gas displacement. Foam stability has a key role on the efficiency... 

Separation of biomolecules such as enzymes is the most important part of biotechnology process which 10-90 % of costs is for separation and purification. There are several methods for purification of bio materials and one of them is chromatography which use in enzyme purification but this method have several problem such as cost ,time consuming and scale up Because of this a suitable alternative demands for industrial separation. An alternative is aqueous two-phase systems (ATPS). In this project was studied about partial purification of alkaline protease produced by Bacillus licheniformis ATCC 21424 in aqueous two-phase system and comparison with chromatography method. an aqueous two-phase... 

Industrial enzymes can generally be classified into three groups: carbohydrases, proteases and lipases, which account for a major part of the global enzyme trade. Proteases, in particular, have always been extensively studied and investigated due to their widespread use in various industries, such as food, pharmaceutical, chemical, and agricultural sectors. Proteases are a group of proteolytic enzymes that break down proteins and peptides into their constituent amino acids by hydrolyzing peptide bonds. Among the family of proteases, alkaline serine proteases have special biocatalytic abilities in both aqueous and organic environments. Their suitable resistance in alkaline environments and... 

Major bone defects resulted from diseases or hurts that can not heal naturally, requaire bone transplantation. golden standard for transplantation is autologus one but it has some disad-vantages such as economic burden, the lack of graft source, surgery on patient, and so on. so exploring altrnative ways led to exploit stem cells.traditionally bone marrow mesenchymal stem cells (MSCs) used for stem cell-bsaed bone regeneration. bone marrow aspiration to aquaire stem cells is painfull and give a population of cells such as hematopoetic cells that requaire to seperate and can not be handled in first passages. MSCs can be substituted by multipotent adipose tissue-derived stem cells (ADSCs) in... 

Nowadays, due to the increasing importance of environmental issues, cement replacement has been considered by many researchers .Determination of behavioral characteristics and fracture of materials such as fracture hardness and energy is used to describe the formation and progress of cracks in new building materials. On the other hand, one of the concrete that can be replaced ordinary concrete is slag concrete. Slag concrete is in the category of Geopolymer Concrete. This concrete is produced by activation of puzzulanic material by alkaline solution.There have not been many studies on the failure of slag concrete. Therefore, in this study, the mechanical properties of slag concrete were... 

Microbial proteases are among the most important hydrolytic enzymes and havebeen studied extensively since the advent of enzymology. They are essentialconstituents of all forms of life on earth, including prokaryotes, fungi, plants andanimals.In recent years there has been a phenomenal increase in the use of alkaline protease asindustrial catalysts. Alkaline proteases (EC.3.4.21–24, 99) are defined as thoseproteases which are active in a neutral to alkaline pH range. Cell immobilization is a technique that restricts the free movements of microorganisms in the process and it has a lot of advantages including this fact that biotechnologists’ dream for using continuous system in fermentation... 

In this research, the optimization of culture medium and process conditions for the production of alkaline protease enzyme from Bacillus subtilis ATCC6633 strain for use in the detergent industry has been discussed. Among all the conditions affecting the growth and production of enzymes, the stirrer cycle in the fermenter, which causes different shear rates and is one of the most important factors in the amount of mixing and aeration, was chosen for further study. At first, the results obtained from the incubator shaker were carefully examined, and then different checks were made to adjust the fermenter stirrer speed through diagrams in three flow states: 1-laminar, 2-transitional, and... 

Chemical flooding has great potential to recover significant fractions of remaining oil for medium to heavy oil reservoirs not applicable for thermal recovery techniques. Nowadays, with gradual crude oil price increase the chemical process is receiving renewed attention, however, illustration of the possibility of various chemical injection scenarios for medium to heavy oil reservoirs has not been clearly reported and these kinds of reservoirs require more investigation for the applicability of these techniques in the fields. The interfacial active molecules are responsible for providing low IFT range and water/oil emulsions which in many cases could improve the oil displacement efficiency.... 

Rammed earth structures have attracted the attention of engineers and researchers in recent years due to their economic advantages, sustainable development, and environmental sustainability. One of the main concerns for public opinion for acceptance of Rammed Earth as a reliable construction material is their durability. Previous studies have investigated the durability of rammed earth materials by conducting wet and dry cycle test, accelerated erosion test, and rain simulation in the laboratory environment. This research studied the durability of cement stabilized rammed earth (CSRE) for one year under the aggressive environments. Three cement contents were considered for preparing the CSRE... 

Almost all of the country's industrial enzyme needs are met through imports. In this regard, much attention has been paid to industrial production of detergent enzymes such as protease, lipase, amylase and cellulase. Proteases, are the most important industrial enzymes with 60% of the world's enzyme market. Extracellular alkaline proteases of microbial origin are most widely used in the laundry detergent industry to help clear protein stains on clothing caused by blood, milk, eggs, and meat. In this study, bacterial alkaline protease enzyme produced by Bacillus subtilis ATCC6633 was used as a model of functional enzymes in detergent industries.Enzyme immobilization-drying operations are one... 

In this research, we have studied optimization of culture medium and process factors for high alkaline protease production from Bacillus subtilis ATCC 6633 for detergent usage. Five parameter soy bean meal, initial pH, agitation rate, MgSO4, CaCl2 were selected for more studies. At first, one-factor-at-a-time method was applied to investigate effect of each factor separately. Then, optimum condition for maximum protease production was achieved using Minitab software Box-benhnken procedure. According to results, high protease production was seen in soy bean meal, 35 (g/L); MgSO4, 1 (g/L); CaCl2 , 1.5 (g/L); initial pH, 7; agitation rate, 150; inoculum ratio, 12% (v/v). The activity of the... 

Genetic engineering of cells has been one of the most effective ways to increase protein production in wild strains. Among the various genetic engineering techniques, the CRISPR/Cas9 system that directly edits the cell chromosome, yielding greater efficiency and easier operation. In this study, we used this system to modify the genome of Bacillus subtilis ATCC 6633 to increase the production of extracellular alkaline protease enzyme. Alkaline protease enzyme has many applications in different industries, but in this study, the application of this enzyme in the detergent industry has been considered. To increase the production of this enzyme, we disrupted and prevented the gene responsible... 

In this study a systematic effort was made to investigate the poisoning effect of sulfur-containing materials on the electro- oxidation of methanol and ethanol on Ni and Cu electrodes in alkaline solutions by the methods of cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Activation energy of methanol electro-oxidation in the absence of Na2S was obtained 30.7 kJ/mol by cyclic voltammetric at different temperatures, and its values increased by increase in Na2S concentrations to 97kJ/mol. Na2S adsorption isotherms corresponded with Langmuire isotherm, equilibrium constants of adsorption – desorption and adsorption enthalpy (ΔHads= -62kJ/mol) were calculated for...