فهرست مطالب ali akbar safekordi

In this research, the interaction of boron nitride (6,6) nanotubes with a length of 8 nm with vitamin B6 (pyridoxal phosphate) was theoretically investigated and the effects of electron destabilization, dipole-dipole interactions and steric repulsions on the structural and electronic properties and The reactivity of vitamin B6 (pyridoxal phosphate) in the presence of single-wall boron nitride (6.6) nanotubes with a length of 8 angstroms was studied using density functional theory quantum mechanical calculations at the B3LYP computational theoretical level and G* 31-6 basis series. . In order to determine the electrical conductivity and chemical behavior of boron nitride nanotubes in reaction with vitamin B6, electron energies, dipole moments, energy gap of homo-lomo molecular orbitals, chemical hardness (η), electron chemical potential (μ) And Mulliken's electronegativity (χ) and adsorption energy (EAd) were investigated in the gas and solvent phases. The results showed that the adsorption energy in the gas and solvent phases is -12.962 and -7.895 kcal/mol, respectively, which shows that the adsorption reaction is feasible in both phases in terms of energy. In the gaseous phase, the energy gap in the encapsulated vitamin B6-boron nitride nanotube mixture (3.517 Eg= electron volts) has decreased compared to the energy gap in the vitamin B6 molecule alone (4.561 Eg= electron volts). In the vitamin B6-boron nitride nanotube encapsulated mixture, with the reduction of the Eg energy gap, the hardness parameter has decreased, the softness parameter has also decreased, and the electronegativity and electrophilicity values ​​have increased.

This study aimed to use D-optimal combined design, and partial least squares discriminate analysis (PLS-DA) to investigate the mechanical properties, and chemical compatibilities of improved epoxy nanocomposites by nano TiO2/Al2O3. Experimental design of adhesion, and wedge bend properties led the results into the optimum values of TiO2= 0.66%, Al2O3= 1.33%, dispersant= 0.000017%. The variable importance of the projection (VIP) score and PLS-DA modeling were used to categorize mechanical properties and chemical compatibilities. The best point could be identified from the other samples, based on the results. PLS-DA could explain 94.32% of the total variance in the data and wedge bend, adhesion and thermal treatment were the most significant variables with VIP scores at 2.73, 2.02, and 1.38, respectively. The morphology was examined using a field emission scanning electron microscope (FESEM). The thermal properties of nanocomposites were described by differential scanning calorimeter (DSC) to define the glass transition temperature for epoxy-nanocomposites. The mechanical properties were measured to assess the storage modulus via the dynamic mechanical analysis (DMA). Epoxy/TiO2/Al2O3 nanocomposite exhibited a uniform particle distribution, as indicated by the FESEM image. Adding nanoparticles significantly raised the glass transition temperature. The presence of nanoparticles can be used to enhance storage modulus functionally.

Bisphenol A (BPA)-based epoxy resins are widely used in food contact materials such as metal can coatings. The adverse effects of bisphenol A on the consumer have led the food packaging industry to continually improve safety. In this study, epoxy coatings manufactured with nanoparticles are subjected to migration testing in order to identify bisphenol A diglycidyl ether (BADGE) migration from the coatings. Migration of BADGE from epoxy/TiO2/Al2O3 nanocomposite into ethanol 10% (v/v), ethanol 20% (v/v), ethanol 95% (v/v), and acetic acid 3% (w/v) food simulants was studied at conditions of contact filling (60 min at 60 and 121°C) and storage condition (10 days at 40 °C). High-performance liquid chromatography (HPLC) was developed to determine the level of bisphenol A diglycidyl ether (BADGE) that migrated from the nanocomposite to the food simulants. The results indicated the levels of BADGE migrating from epoxy/TiO2/Al2O3 nanocomposite to the food simulants under the conditions of contact filling and storage did not exceed the specific migration limits.

Enhanced Oil Recovery from carbonate reservoirs is a major challenge especially in naturally fractured formations where spontaneous imbibition is a main driving force. The Low Salinity Water Injection (LSWI) method has been suggested as one of the promising methods for enhanced oil recovery. However, the literature suggests that LSWI method, due to high dependence on rock mineralogy, injected and formation water salt concentration and complexity of reactions is not a well-established technology in oil recovery from carbonate reservoirs. The underlying mechanism of LSWI is still not fully understood. Due to lack of LSWI study in free clay dolomite fractured reservoir, and to investigate of anhydrate composition effect on oil recovery in this type of reservoir, the main purpose is the experimental evaluation of oil recovery from one of the Iranian naturally fractured carbonated (dolomite containing anhydrate and free clay) reservoirs using LSWI. For this purpose, a set of experiments including spontaneous and forced imbibition is conducted. To obtain the optimum salt concentration for oil recovery, the secondary mode of the spontaneous imbibition tests is performed by seawater in various salt concentrations at the reservoir temperature (75°C). Also, the tertiary recovery mode is subsequently applied with optimum brine salinity. The lab results reveal that by decreasing the injected water salt concentration, oil production increases. Furthermore, in order to upscale the experimental results to the field scale, a more precise dimensionless-time correlation is used. Due to some inconsistencies over the influence of mechanisms on LSWI oil recovery, the mineral dissolution, pH-increase mechanisms, and wettability alteration are also studied. The results indicate that wettability alteration is the main mechanism and mineral dissolution may be the predominant mechanism of the improved oil recovery in the studied reservoir. It is noticed, the elevation of pH led to enhanced oil recovery when high dilution of low salinity water is implemented.

In an attempt to develop the methodologies used for oil spill clean-up, polyurethane sponge was modified by deposition of NiFe2O4 nanoparticles on the surface of the original polyurethane sponge under ultrasonic treatment. The fabrication process was facile and low-cost. The as-prepared magnetic sponge exhibited remarkable features including great porosity,high oil adsorption capacity, hydrophobicity, and reusability. In addition,the magnetic property of the modified sponge facilitated the process of oil-water separation. Indeed, the hydrophobicity of the modified spongecontributed to the adsorption of different types of oil and organic solvent on the sponge surface. The modified sponge exhibited the same characteristic peaks as those of the NiFe2O4 magnetic nanoparticles, ascertaining the formation of the crystalline nickel ferrite nanoparticles. The XRD and FTIR results proved the formation of the composite. FESEM images of the nanocomposite showed a highly porous mulberry-like structure with a rough skeleton. More importantly, the oil and water contact angle measurements proved the hydrophobicity of the modified sponge.

The water injection process and flooding for many years as one of the most important practical methods to maintain reservoir pressure and improve the flow of oil to the production wells are known. The results of the studies show that the rock composition and salinity water injection have a significant impact on flooding process efficiency. Low salinity water injection because of the availability of water and its compatibility with the environment and cheaper than other methods of injection is practical. The experimental results showed that the highest oil recovery is achieved when the concentration of salt in water injection is less than the formation water. Several mechanisms to describe the low salinity water injection for enhanced oil recovery. As stated that the migration of clay particles, changing the wettability, ion exchange, expansion of the dual-layer, changing PH, dissolved minerals, and salt effect. Interactions and interactions between mechanisms have added the complexity of understanding the exact efficiency of low salinity water injection. Although it is generally believed that low salinity water injection causes enhanced oil recovery factor, but because of inconsistencies in the results of some tests there were doubts in this regard. In addition to the low salinity water injection will be referred challenge for association studies.

Methylene blue is the most common colored material that is used to stain cotton, wool and silk; it has a high global consumption, and is found in high-tech textile wastewater. In this study, the photocatalysis degradation reaction of methylene blue (MB) in polluted water was performed using a ZnFe2O4-ZnO-perlite nanocomposite in suspension condition under UV and visible LED illumination in a batch photoreactor. To prepare ZnFe2O4-ZnO-perlite nanocomposite, first, ZnFe2O4 nanospheres were synthesized by hydrothermal route, ZnO nanoparticles were prepared via sol-gel method in media containing perlite and ZnFe2O4. To detect prepared nanocomposite, scanning electron microscopy (SEM) images, Fourier-transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD) pattern were used. Effects of operating factors on photocatalyst degradation such as catalyst amount, powers of UV and visible LED lamps, radiation duration and reaction temperature were investigated. The highest efficiency was obtained under optimal conditions (3 g/L photocatalyst amount, UV power and LED power of 20 watts, the radiation time of 120 minutes and temperature of 35 ºC). The kinetic reaction was investigated in optimal conditions and the results showed that its kinetics was first order and the results were acceptable in these studies. Based on these results, a method for photocatalytic degradation was obtained using a ZnFe2O4-ZnO-perlite nanocomposite, which can be used to expand it into industrial form, for wastewater treatment in industry.

In recent years, edible coatings have been extensively used for extension shelf life of fruits and vegetables. In this research, the effect of washing with citric acid (1%w/v) followed by coating with different concentrations of carboxymethyl cellulose (CMC;1, 1.5 and 2% (w/v)) in combination with ascorbic acid (AA; 1, 2 and 3% (w/v)) on postharvest quality of button mushrooms when stored at 4  for up to 15 days was studied. After treatment, mushrooms weight loss, soluble solid content, firmness, color, microbial and sensory quality were evaluated at 1, 4, 8, 12 and 15 days of storage. The result indicated that coating reduced weight loss and delayed changes of soluble solid content and color compared to uncoated control mushroom. Coatings had not remarkable effect on firmness of mushrooms. Sensory evaluation showed that the shelf life of mushrooms increased from 8 to 15 days. Washing with citric acid reduced total bacteria, yeast and mold counts. Among different coatings the combination of CMC 2% and AA 3% was more effective.

In the present study, the performance of a batch suspension photoreactor has been investigated and compared with a catalytic-membrane photoreactor (PMR) for removal of Basic Violet 16 (BV16) from synthetic effluent. Initially, influence of the effective parameters on the photocatalytic process in the presence of Zinc oxide doped with calcium (ZnO: Ca) such as photocatalyst dosage, pH, temperature, initial dye concentration and aeration was studied. Based on the results, the optimal condition of the process was: Catalyst dosage (0.06 g.L-1), normal pH (5.5), ambient temperature, Dye concentration: 10 mg.L-1 and Aeration: 5.5 L.min-1, respectively. The results showed that the removal efficiency at the high concentrations decreases in the photocatalytic process. This will reveal the need to integrate a system as pre-treatment of input feed prior to the preparation. In this study, a polyvinylidene fluoride-based membrane (PVDF) was used as a pre-purification agent before the batch rector system. The results of the research and the calculation of process efficiency show that PMR has been successful in removal of BV16 dye in the same concentrations and also more than the optimal dye concentration of suspension system. Comparing the kinetc of the reactions, the constant reaction rate in PMR increased by about 14% in comparison of the batch system at the optimal concentration (60%) and above the optimal concentration (30 mg.L-1).

organic solvents. In this study, NiFe2O4/sawdust nanocomposite was synthesized for removingoil pollutants. The oil-adsorbing nanocomposite could be easily separated from water bymagnet bar. The XRD results show tetragonal phase proving the composite formation. TheFESEM pictures successfully reveal the growth of NiFe2O4 on the sawdust template. The FTIRbands at 422 cm-1 and 615 cm-1correspond to the metal oxygen stretching band. VSM hysteresisloop proves the superparamagnetism of the composite. In addition contact angle depictshydrophobic properties of the resulted nanocomposite. More importantly, as-preparednanocomposite exhibited high oil adsorption capacity and good reusability. Our studies showeasy synthesis and fast method for oil removal from water. Facile synthesis procedure, highoil adsorption capacity, fast and simple magnetic separation and reusability of nanoadsorbentare among the benefits of these composite. This approach will open up new fields of studiesin polluted-water treatment.

In this study used of expanded perlite were modified with emulsifier and their potential usefulness in combating oil spill. the data experimental show that when this perlite is added to water-oil mixture، the light particles (40-200kg/m3) move on the surface spreading over it very quickly. The expanded perlite has high surface area (3000cm2/gr) and high porosity (>90%). However expanded perlite be ability adsorb oil spill and to form clog. It seems that if the emulsifier without expanded perlite adds to water-oil mixture، emulsifier as a pollutant enters to sea medium. The expanded perlite were modified by emulsifier can emulsify oil spill that is 35 times heavier than is own weight، so adsorbed oil with expanded perlite were modified can with use Mechanical instrument as booms and pumps collected of surface sea water.

Human granulocyte macrophage colony stimulating factor (hGM-CSF) has many therapeutic applications. In this study, in order to verify the purification process, the effect of carbon source, IPTG concentration and post-induction time on the secretion of recombinant hGM-CSF into the culture medium by recombinant Escherichia coli during high cell density cultivation were evaluated by using the Taguchi statistical method. The results indicated that glucose, 1mM IPTG and a time of 6 h post-induction, represented optimum conditions. The secreted hGM-CSF, overall volumetric productivity and purified hGM-CSF were 373 mg/l, 18 mg/l/h and 63 mg/l, respectively.

Waste heat recovery is very important, because not only it reduces the expenditure of heat generation, but also it is of high priority in environmental consideration, such as reduction in greenhouse gases. One of the devices is used in waste heat recovery is heat pipe heat exchanger. An experimental research has been carried out to investigate the hydrodynamic and thermal performance of a gas- liquid thermosyphon heat exchanger in a pilot plant. The ε-NTU method has been used. The pressure drop has been calculated across tube bundle of the thermosyphon heat exchanger. Its module is composed of 6 and 15 copper pipes with aluminum plate fins with dimensions of 130 cm, 47 cm and 20 cm. The tubes have been filled by water with filling ratio of 30 %, 50 % and 70 %. The density and thickness of fins are 300 fin/m and 0.4 mm, respectively. The configuration of tubes is in-line with 30 mm pitch. The results show that as the ratio of Ce/Cc raises the amount of heat transfer increases. The effectiveness of heat pipe heat exchanger remains constant as the temperature of hot stream rises, but the amount of heat transfer increases. Filling ratio in normal region (30-70 %) has no effects on experimental results. A new correlation for thermosyphon heat exchanger with individual finned tubes and in-line geometry has been proposed for calculating pressure drop across tube bank of a. The error in pressure drop for 40 experimental points in the new correlation is less than 15 %. This indicates that the new correlation possesses an acceptable accuracy predicting pressure drop