Sharif Digital Repository

In 2009, a general equation of state (EOS-III) based on an effective near-neighbor pair interaction of an extended Lennard-Jones (3, 6, 12) type has been introduced as : , where is the compressibility factor, p and ρ stand for pressure and molar density , respectively, T is Temperature , and e, f and g are the temperature dependent coefficient of the equation of state . the Z_th and Z_in are the thermal and internal contributions of pressure in the compressibility factor, respectively. this equation of state gives a good description of all types of nano- and bulk –solid and bulk fluid at entire temperature and pressure ranges for which thee is experimental data. Investigation show that... 

The rise in carbon dioxide levels has led to the manifestation of numerous environmental challenges. Currently, the absorption and conversion of carbon dioxide into valuable fuel resources such as synthetic gas, methane, and ethylene are deemed crucial from both environmental and economic standpoints. Despite the presentation of photocatalysts such as titanium oxide and electrocatalysts such as copper, silver, and zinc, their efficiency in CO2 conversion is found to be insufficient. One potential solution to this problem is the utilization of photoelectrocatalytic CO2 recovery. In this study, the aim was to enhance the photoelectrocatalytic reduction of CO2 by designing and manufacturing... 

Preformed particle gels (PPGs) due to its advatantage over commonly used in situ gels has been successfully applied for controlling excess water production in mature oil reservoirs. Field results of using PPGs in oil fields shows that commonly used PPGs are highly sensitive to hard reservoir conditions such as high temperature and salinity and can not effectively block fractures and high permeability layers.Objects of this study are synthesis and evaluating performance of this novel polymer based hydrogel in oil reservoirs with high temperature and salinity. Central composite design ( which is a experiment design approach) was used for synthesizing thirteen gel samples and optimal sample was... 

Biological layers are one of the main problems related to water transfer with pipe lines which are formed through time in the inner surface of the pipes by the water nutrients. Hence, the inner surfaces in the pipe lines and water refineries should be made in order not to let these biological layers to be made. The reason is that when the biofilm is formed on these surfaces, the traversing water is polluted. Dredging of these pipes is not only necessary in most of the countries in the world and needs huge amounts of water but is also very complex and expensive.In this research, nanomaterials, namely ZnO, T〖iO〗_2،S〖iO〗_2 have been used to cover the surface of concrete and steel pipes (The... 

Sand production from oil reservoirs leads to various problems, such as well productivity reduction, operating equipment corrosion, and increased production costs. Therefore, controlling sand production in unconsolidated reservoirs is crucial for operating companies. Chemical injection into the formation in order to strengthen and reduce sand production is one of the most important methods of sand control. In this study, a hydrogel nanocomposite was designed and its effectiveness in sand control was investigated. Various tests were carried out to define and assess its efficacy, as follows: Morphological tests demonstrated the creation of a dense, homogeneous, and porous structure. Structural... 

Despite of many advantages, electro submersible pumps (ESP) have very high costs in maintenance. Since ESP usually operates in deep wells, it should be transported to the surface in order to malfunction. In addition, the state of ESP equipment cannot be determined because of unavailability of vibration measurement on the site. Thus, this equipment fails suddenly. This process costs a lot on country’s oil and water & wastewater industry. so in this thesis, at first, the potential failure modes (PFM) of ESPs are investigated, then proper methods are presented for condition monitoring. Finally, the presented methods are verified by experimental tests and wavelet analysis. The results show that... 

Atom transfer radical polymerization (ATRP) is a convenient approach to synthesis of polymer with narrow molecular weight distribution. ATRP of acrylamide (AAm) is taken into consideration because of the intrinsic properties of acrylamide such as water solubility and biocompatibility. As reported in many recent works, polymerization of acrylamide by this method didn’t provide monomodal molecular weight distributions. In best condition with strong ligands such as Me4Cyclam, polymerization was carried out in a short time with high yield but polymerization was not highly controlled. It was shown that polymerization of acrylamide under typical ATRP condition displayed a much lower ATRP... 

In this thesis its considered the characterization of an ultrasound wave in a medium with some obstacles. Derivation of speed of molecules and pressure of the wave is carried out in the Cartesian coordinates system. Simulation is carried out to prove the dependency of wave speed to set up parameters such as the target point (x,y,z) at which the speed value is obtained, the location of the obstacles, the amplitude of original wave emitting from the source, and the propagation speed in different layers of the medium. From the numerical results, it is apparent that the amplitude of the speed wave gets degraded as the wave travels through the medium which is a function of reflection and... 

Carl Jung's analytical psychology is a psychoanalytic theory that has been established with the assumption of the existence of a collective and inheritable unconscious containing archetypes. The archetypes are psychic patterns that have evolved throughout human history and are inherited by human infants. Repressing these innate and universal properties can cause psychic problems for humans. Those repressed innate properties could emerge indirectly to keep the mental balance, but this may cause problems due to being out of conscious control of the individual. According to Jung's claim, remembering and accepting these repressed identities and then integrating the conscious and unconscious... 

As fossil fuels are still the world's most important source of energy, as well as the maturity of most of the world's oil reservoirs, there is a need for enhanced oil recovery methods to meet the world's increasing oil demands. MEOR methods are new and promising methods that are still in the research and development stage. One of the MEOR methods is the use of biosurfactants, which increase the oil recovery by two mechanisms: 1) reducing the interfacial tension between water and oil and 2) changing the wettability of the rock. In this study, the performance of two glycolipid biosurfactants, rhamnolipid and sophorolipid, in increasing oil recovery has been investigated. Initially, surface... 

During the production of crude oil from reservoirs, the production of quantities of formation water along with this oil, causes the crude oil does not have the necessary indicators for transportation, refining and ultimately export. The presence of water and salt along with crude oil causes corrosion of refinery and transmission equipment and makes oil unfavorable in terms of economic efficiency (both for domestic use and for export). water and salt produce stable emulsion with oil that can be stable for a long time and can not be easily separated from crude oil. Therefore, separation of water and salt from crude oil is one of the most important issues in the oil industry. Breaking this... 

Considering the limitations of fossil fuels in recent years, as well as increasing demand for biofuels, it is anticipated that future attention to biofuels will increase further. Among biofuels, due to some disadvantages of bioethanol and biodiesel fuel, there is a tendency to use biobutanol, which does not have the disadvantages of the mentioned fuels. The cost of chemical production of butanol also led researchers to use biotechnology production of butanol. According to studies, butanol production can be achieved by fermenting some sugars such as glucose, xylose, and ... by anaerobic microorganism, but the cost of using these sugars has resulted in the use of natural sources of these... 

The methods of Enhanced Oil Recovery (EOR) from reservoirs have been taken into consideration recently due to the decline in oil reserves and the rise in energy demand. Studies and investigations indicate the tremendous potential of chemical approaches based on injecting ionic liquids into the porous media with the goal of improving oil recovery. Additionally, hydrogels and polymers, which are two of the process' primary materials, are thought to be good alternatives. In the current study, a hydrogel based on carboxymethyl cellulose was first created and synthesized. Ionic liquids based on imidazolium and triflate anion were then added, and their effectiveness in enhancing the properties...