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Showing 46 results for Recovery


Volume 1, Issue 1 (12-2017)
Abstract

The adsorption of polymeric systems onto reservoir rock through altering the wettability of rock surface improves oil recovery and reduces the unwanted water production. . In this study, the adsorption behavior of dilute polymeric systems based on sulfonated polyacrylamide  on the glass particles surfaces (representative of sandstone reservoirs) was investigated and the effect of this phenomenon on changing their surface properties was examined. Results show that crosslinked polymeric samples have lower adsorption on glassy surface comparing with uncrosslinked sulfonated polyacrylamide solution. Furthermore, the contact angle tests results showed that crosslinked samples change the surface property of glass particle less than sulfonated polyacrylamide solution. In addition the Langmuir isotherm model fitted the isotherm data better than the Freundlich model for these dilute polymeric systems. Furthermore, study of the thermodynamic of adsorption showed that their adsorption behavior on glassy surfaces is a spontaneous and exothermic process. 

Volume 1, Issue 1 (3-2023)
Abstract

Nowadays, application of enhanced oil recovery methods has increased; therefore it’s necessary to determine their impacts on environment and human life. So, this research investigates the environmental impacts of conventional enhanced oil recovery methods and new methods such as using electromagnetic waves, ultrasound waves, and nanoparticles. The investigations show that electromagnetic waves and ultrasound can effectively remove many environmental pollutants. Characteristics of the wave and the type of formation determine that these waves have different effects on the formation, and efforts should be made to understand these effects to prevent damage to the formation. Nanoparticles can also reduce the quantity of pollutants in the environment. According to the mechanisms of entrapment of nanoparticles in the porous medium, they may remain in the reservoir and find their way to the underground water over time, so their environmental effects should be considered in the long term. A better knowledge of new methods of increasing oil extraction will lead to the identification and use of more suitable methods with less environmental effects (compared to conventional methods).

 


Volume 2, Issue 1 (6-2018)
Abstract

Electronic wastes are known as the most important solid wastes in 21th century. They are producing two or three time faster than other solid waste streams. Many researchers studied bioleaching of e-wastes using Acidithiobacillus ferrooxidans. The presence of alkaline metals cause e-wastes show an alkalinity nature. By adding e-wastes to the environment the pH of solution increases sensibly. Many researchers supposed the optimal pH range of A. ferrooxidans which is 1.5-2.5 as the optimal pH range to reach maximum recovery. So in the bioleaching process by daily pH adjusting in the range and using sensible amount of sulfuric acid, control the pH of solution about 2. In this research two same experiments, just the pH of one of them was adjusted daily, were done. In both experiments the environmental situation including pulp density of 15 g/l, inoculum 10% (v/v), the temperature of 30ºC, and shaking rate of 130 rpm was the same. For 25 days Cu recovery, bacterial count, pH, and Eh were examined. The results showed the maximum Cu recovery at the sample without pH adjusting was about 100% but at the sample with pH adjusting recovery was reduced to 90%. The bacterial count diagram showed the bacterium is well active in both experiments. To maximize recovery, reducing acid consumption, and increasing process economy there is no need to adjust the pH of solution.

Volume 2, Issue 2 (9-2018)
Abstract

In recent years, with the advancement of nanoscience, many scientists have used nano materials to solve existing problems in various sectors of oil industry. Nanofluids made with these materials can facilitate the separation of oil and gas in a reservoir and increase oil recovery factor compared to current methods. Therefore, in this work, the effect of clay nanoparticles on oil recovery factor was investigated. For this purpose, two different base fluids, water and ethanol, were used to disperse the nanoparticles. The effect of adding clay nanoparticles on viscosity changes and interfacial surface tension was determined. Also, in order to investigate the effect of nanoparticle concentration in the base fluid on the ultimate oil recovery factor, nanofluids with 3 and 5 wt% were prepared. Results show that oil recovery factor increases significantly in these conditions by adding them into the base fluid, though nanofluids included clay nanoparticles have less stability. Also, the effect of these nanoparticles dispersed in water is greater than in ethanol. For example, at 5 wt%, oil recovery factor for water based nanofluid was 49.7% and for ethanol based nanofluid was 46%.

Volume 2, Issue 3 (2-2019)
Abstract

In this study, the effect of chemical modification on adsorption behavior of scleroglucan polymer on carbonate rock of oil reservoir was studied. The chemical modification was performed to increase hydrophobicity of scleroglucan while substituting ionic and hydrophobic groups on its structure simultaneously. Investigation of adsorption behavior of the samples on carbonate rock surfaces revealed an increase in uptake of the modified samples compared to the original one. Evaluation of various factors affecting the adsorption process showed that the Langmuir isotherm can describe the adsorption behavior of primary and hydrophobic scleroglucan samples better that Freundlich & Temkin isotherms. However, the adsorption behavior of the ionic-hydrophobic sample was hard to explain using the Langmuir model. A pseudo-second-order & Intra-particle diffusion models could express uptake kinetics of the samples. Thermodynamic studies indicated the temperature-dependency of free energy, ΔG, and the dominant role of entropic phenomena, rather than enthalpic phenomena, in the adsorption process of samples. In addition, ΔH values of different samples (about 6 KJ/mol for the primary scleroglucan, 5 KJ/mol for the hydrophobic scleroglucan and 9 KJ/mol for the ionic-hydrophobic scleroglucan) suggested the physical adsorption of samples onto the carbonate particles surface in both water and brine solutions.
 


Volume 3, Issue 1 (3-2014)
Abstract

Xanthomonas campestris pv.musacrearum causes Banana wilt disease (BXW disease) which occurs at different epidemic phases in East and Central Africa (ECA). In the endemic areas, there are many banana fields with over 80% BXW disease incidence. This study aimed at rehabilitating banana fields heavily infected with BXW disease in Uganda, Kenya and DR. Congo. Farmer managed trials were established in BXW disease hotspots in western Kenya and DR. Congo, while in Uganda, similar trials were established at community level i.e. clusters of at least 200 heavily infected banana fields. The control options evaluated included single stem removal, suspension of pruning in affected fields, male bud removal and disinfection of tools with fire or Sodium hypochlorite. Data was collected on the proportion of affected fields (BXW disease prevalence), BXW disease incidence and the number of banana bunches sold at 3-month intervals. BXW disease incidence was reduced by over 80% in 11 months in Kenya and DR. Congo, resulting in yield recovery by up to 70% within one year. In Uganda, the proportion of farmers that effectively controlled BXW disease increased 5% to 60% within a year in some hotspots. Consequently banana sales recovered up to 30% in some hotspots. This study demonstrates that it is possible to effectively control BXW disease within 12 months in previously severely infected fields in various areas of ECA.  

Volume 3, Issue 1 (5-2019)
Abstract

Research Subject: Nowadays, application of biosurfactants in microbial enhanced oil recovery (MEOR) have aroused much attention and several investigations have been conducted on this field. But their performance in comparison to synthetic surfactants in enhanced oil recovery has little been studied. Most of these researches are limited to comparison of one produced biosurfactant with only a chemical surfactant. To fill this gap, in this research, the potential use of a rhamnolipid type biosurfactant  in MEOR was compared to several conventional synthesized surfactants: SDS, SDBS, CTAB and DTAB.
Research Approach: Since the main goal of this research is the comparison between produced biosurfactant and conventional chemical surfactants in oil recovery, several flooding tests were conducted and involved mechanisms were investigated. All of tests were conducted in an oil wet glass micromodel saturated with heavy oil at ambient condition. Injected solutions were prepared at critical micelle concentration of surfactants. During the flooding tests, high quality pictures were taken with a camera connected to the computer to monitor the motion of injected solution in the micromodel.
 Main Results: 40% oil recovery was achieved after biosurfactant flooding while SDBS, SDS, CTAB and DTAB resulted 36%, 34%, 32% and 29% oil recovery, respectively. For mechanistic study, the surface tension (ST) and viscosity measurements were performed and contact angle was determined. The surface tension reduction, wettability alteration towards more water-wet condition and increasing the ratio of injected fluid viscosity to oil viscosity were dominant mechanisms. The rhamnolipid was more effective than other surfactants in reduction of surface tension and altering the wettability towards favorable water-wet conditions. It decreased the surface tension of water from 72 to 28 mN/m, which was the least comparing to other surfactants and increased the capillary number about 19.4 times greater than in water flooding. Additionally, it changed the contact angle from 106 to 6, 94.3%, the widest change among applied surfactants. 



Volume 4, Issue 2 (9-2015)
Abstract

The aim of this study, in the first step, was to recover the protein content in wastewater of fish meal factories using chitosan, chitosan nanoparticles and chitosan-aluminum sulphate composition. In the second step, the extracted protein was assessed for its  essential amino acids profile.  Also, the  reduced amount of proteins in the waste water was evaluated by measuring different parameters such as turbidity, pH, COD. Finally, chitosan nanoparticles characteristics were investigated using atomic force microscopy. Results showed that turbidity, COD and soluble protein significantly decreased upon  adding different concentrations of chitosan, nanoparticle of chitosan and chitosan-alum (p<0.05). The maximum protein recovery was related to chitosan-alum composition and chitosan nanoparticles with no significant difference between these two treatments. Evaluation of recovered protein in term of amino acids profiles showed that there were essential amino acids such as histidine, lysine, methionine and phenylalanine in protein of fish meal wastewater.      

Volume 5, Issue 1 (7-2021)
Abstract

Abstract:
Research subject: Leaching and recovery parameters controlling the releasing of selenium from Sar-Cheshmeh copper anode slimes are studied and determined.
Research approach: Copper anode slimes is produced during the production of cathodic copper at the bottom of electrolyte cells, which is composed of insoluble anode components in the electrolyte. The copper anode slimes are made up of those components of the anodes, which are not soluble in the electrolyte. They contain varying quantities of precious metals like gold, silver, selenium and tellurium, and other precious metals in the anodic copper. They are being extracted as a by-product in the copper production process. Due to the fact that the main source of selenium is sulfur deposits such as copper and nickel. Copper anodic slimes is currently the only source of selenium in the world. In this study, the extraction of selenium from anodic copper slimes has been feasible. To do this, acid leaching has been used. Copper anodic sludge is the raw material for the production of more than 90% of the world's selenium and is the main source of selenium production.[1-3]
Main result: In this paper, the effect of operational parameters such as acid concentration, temperature, process time and liquid to solid ratio on selenium recovery through copper slimes leaching was investigated. The optimum conditions of batch leaching For maximum selenium extraction from anodic copper slimes are attained at 3 mol L-1 of HNO3 concentration, 0.01 (W/V) solid to liquid ratio for 60 min contact time at 70 º­C. Under the optimized conditions, the selenium leaching efficiency was 99%. The thermodynamic data showed positive values of both ΔH and ΔS which indicates that the leaching process is indeed endothermic and random while the obtained negative values of ΔG show that selenium dissolution process is spontaneous in nature.

Volume 5, Issue 1 (7-2021)
Abstract

Research subject: Nanomaterials are substances that, because of their size, can easily penetrate small pores and apply their impact. Nanofluids can allow appropriate wettability change in the reservoir rock, therefore, an accurate understanding of the behavioral mechanisms of these nanofluids is important in changing the wettability. This is because if there is no proper understanding of these mechanisms, they may exhibit the opposite behavior and cause damage to the reservoir. In previous research, CuO / TiO2 / PAM nanocomposite was synthesized and mechanistically introduced.
Research approach: In this study, in continuation of the previous study, the behavioral and mechanism study has been investigated in a more accurate and documented manner, and spectral absorption tests, chemical flooding, and relative permeability diagrams confirm the effectiveness of enhanced oil recovery results of this nanocomposite. In carbonate rocks due to the positive surface charge of the rock and the negative charge of the nanocomposite, adsorption of nanomaterials in a double electrode layer state has been suggested as the dominant mechanism of wettability change. In sandstone rocks due to the charge coincidence of rock surface and nanomaterials which are both negative, the mechanism of disjoining pressure was the dominant mechanism of wettability change. To prove the abovementioned behaviors 200 ppm concentration of nanofluid was analyzed by spectroscopy method of adsorption analysis to validate the attraction forces of the nanocomposite with carbonate rocks and repulsion forces with sandstones.
Main results: Dynamic chemical flood tests were performed to confirm the effectiveness of this material in increasing oil production and showed 8.5% and 6.35% increase in oil production for carbonate and sandstone lithologies, respectively. Relative permeability diagrams showed an intersection point in the carbonate system with a 10% increase in water saturation and an intersection point in the sandstone system with a 12% increase in water saturation and the behavioral effect of the material at the studied concentrations.

Volume 5, Issue 4 (4-2021)
Abstract

Research Subject: Global energy demand is increasing, so enhanced oil recovery techniques have incorporated in production processes. Water flooding is a common technique in oil recovery processes. One of the major challenges in this technique is heterogeneity of the reservoir structure which results in increased water production and reducing the oil recovery factor. Moreover, long-term water or chemical injection might lead to the increased horizontal and vertical heterogeneities in the reservoir. Selective blockage of high permeability areas and consequently improved production from low permeability regions is important for increasing the oil recovery factor. In recent years, using hydrogels in injection processes, has been associated with various field successes, indicating the ability of these materials for selectively blocking the areas of high permeability. Hydrogels are injected after water or polymer flooding to conduct the injected fluid to low permeability areas.
Research Approach: In this paper, hydrogel injection process was simulated in glass micromodels using Comsol Multiphysics software. Hydrogel functionality was studied in low permeability areas in porous media. Moreover, the optimized conditions for water flooding process was studies. For this purpose, after model validation, sensitivity analysis was performed on effective parameters on oil recovery factor and a mathematical model was presented to predict the oil recovery factor.
Main Results: Oil recovery factors obtained from experimental and simulation studies, were in good agreement with each other with absolute error values of 2.29% and 4.06%, for water and hydrogel flooding, respectively.
Four parameters of injection rate, contact angle, oil viscosity, and injection fluid viscosity were considered as effective parameters on oil recovery factor. Among them, contact angle was the most important parameter. In water flooding, the most important interacting parameters are viscosity and contact angle and the least important parameters are injection temperature and rate. In water flooding simulation studies, the thickness of the contact surface was obtained hmax/5, where  is 230 micrometers. For hydrogel injection, the contact surface thickness was obtained terpf.ep_default / 5.65. Terpf.ep_default is the thickness of contact surface, equal to 631 micrometers

Volume 6, Issue 1 (4-2018)
Abstract

Aims: Bioactive peptides with antioxidant properties derived from fish by-products and wastes by enzymatic hydrolysis have become a topic of great interest for pharmaceutical, health food, and processing/preservation industries. Materials & Methods This study aimed to characterize peptide fractions with antioxidative activity recovered from rainbow trout gelatin hydrolysate. Four peptide fractions (<3 kDa, 3–10 kDa, 10–30 kDa, and >30 kDa) were obtained from gelatin hydrolysate by subjecting them to centrifugal ultrafiltration using successively a 30 kDa, 10 kDa, and a 3 kDa membrane. The
10–30 kDa fraction was characterized in terms of amino acid composition. The antioxidant activity of all fractions was monitored by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radical scavenging as well as reducing power activity.
Findings: The free amino acids in 10–30 kDa fraction were dominated by Gly, Pro, Ala, and Hyp; the total hydrophobic amino acid of 10–30 kDa fraction was also 61.5%. All hydrolysate and peptidic fractions demonstrated high antioxidant activities. Moreover, 10–30 kDa fraction exhibited the highest DPPH and ABTS radical scavenging activity (2, 5, and 10 mg ml−1) and reducing power (10 mg ml−1) compared to other fractions (p<0.05).
Conclusion: These results revealed the potential of peptide fractions recovered from rainbow trout skin gelatin as source of natural antioxidants for use in food products.

Volume 6, Issue 2 (9-2022)
Abstract

Research subject: In situ synthesis of nanoparticles due to greater impact on production mechanisms (such as reducing oil viscosity), uniform distribution of nanoparticles in reservoir fluids, no reduction in formation permeability due to no injection of nanofluids into the reservoir and also economic efficiency is more importance than other nanoparticle synthesis methods which are used in enhanced oil recovery (EOR) processes.
Research approach: In this study, the effect of in-situ synthesized of cerium oxide (CeO2) nanoparticles at low temperature on the oil recovery factor was investigated. For this purpose, water was considered as the based fluid for dispersion of synthesized nanoparticles. Also, in order to study the effect of nanoparticles concentration in the base fluid on the final oil recovery factor, several nanofluids were prepared at different concentrations of 0.01, 0.1, 0.25 and 0.5 wt.%. Finally, the prepared nanofluids were injected at the injection rate of 0.07 ml/h up to 1 PV into the micromodel and the amount of produced oil and the movement of the injected fluid in the porous medium were analyzed.
Main results: The results showed that the synthesized CeO2 nanoparticles in this study have appropriate performance to improve the oil recovery factor. The presence of small amounts of these nanoparticles (concentration of 0.01 wt. %), causes a significant increment in oil recovery factor (about 7%) compared to water injection alone. Also, the oil extraction coefficient increased by increasing the concentration of nanoparticles in the base fluid. So that for nanofluids with concentrations of 0.01, 0.1, 0.25 and 0.5 wt.%, the oil recovery factor were 25%, 38%, 43% and 45%, respectively. However, by increasing the concentration of nanoparticles in the base fluid, from an optimal amount onwards, the probability of particle deposition in the micromodel increased, the effect of nanoparticles on changing the hydrodynamic properties of the injected fluid and oil production mechanisms decreased.
 

Volume 6, Issue 2 (9-2022)
Abstract

Research subject: External radiotherapy is a major method of treating cancer. For just hitting the cancer cells by emitting rays, masks are used to stabilize the patient's body in the right position during the radiotherapy, so that the rays are not emitted to the healthy tissues of the patient's body. Due to the unique properties of these masks, suitable polymeric materials must be used to produce them, which has initially been investigated using a variety of thermoplastic polymers.
Research approach: In the following, polycaprolactone is proposed as the main material for making the mask. Due to its low tensile strength, this material alone is not suitable for the intended use. Therefore, the material was cured with different percentages of benzoyl peroxide (BPO) to increase tensile strength by crosslinking of the polymer. The properties of the cured samples were investigated using the tests of gel content, shape memory, unidirectional tensile strength and, DSC diagrams.
Main results: With increasing BPO, the percentage of gel content and shape memory of the cured samples increased. All cured samples had a high percentage of shape recovery, the highest of which belonged to samples containing 2 and 3% by weight of BPO. By Examining the tensile strength test diagrams, it was observed that by increasing the amount of BPO from 0.5 to 2% by weight in the cured samples, the tensile strength at the breaking point increased to 10 MPa. Shape recovery and tensile strength at the breaking point were 94% and 10 MPa for both cured polycaprolactone samples with 2% by weight of BPO and the Orfit mask, which were very similar in this respect. Finally, a mixture of PCL with 2% by weight of BPO is proposed to make a radiotherapy mask.
 

Volume 6, Issue 4 (12-2022)
Abstract

موضوع تحقیق: یکی از روش­های نوین در فرآیندهای افزایش بازیافت نفت از مخازن هیدروکربوری، بکارگیری امواج اولتراسونیک میباشد. در این تحقیق با استفاده از امواج اولتراسونیک و اعمال آن در یک مخزن نمونه مقیاس بزرگ، به بررسی اثر آن در ازدیاد برداشت نفت به روش عددی پرداخته شده است.
روش تحقیق: در این تحقیق فرایند مدلسازی با استفاده از نرم افزار متلب انجام شده است. ابتدا با تعیین محیط متخلخل میزان افزایش فشار حاصل از موج اولتراسونیک با توجه به حل معادلات صوت ( هلمهولتز) توسط جعبه ابزار k-waves متلب بررسی شده و سپس با تعیین مخزن نمونه و حل معادلات حاکم بر مخزن میزان تغییرات فشار حاصل از جریان سیال در حضور چاه تولیدی به بررسی اثر موج اولتراسونیک در ازدیاد برداشت نفت پرداخته میشود. در نهایت با توجه به تولید تجمعی در یک زمان مشخص از چاه تولیدی و تعیین بازیافت نفت از مخزن در حضور موج، به بررسی اثر پارامترهای موقعیت مکانی چاه و فاصله آن از منبع تولید موج، زمان شروع تولید موج، شیوه­ای اعمال موج (پالسی و پیوسته)، در یک فرکانس و توان بهینه پرداخته میشود.
نتایج اصلی: با توجه به نتایج بدست آمده از مدلسازی، هرچقدر زمان شروع اعمال موج به روزهای اول تولید نزدیک­تر باشد، میزان بازیافت نفت نیز بیشتر میشود؛ به گونه ای که با شروع اعمال موج اولتراسونیک تحت توان 5 کیلووات و فرکانس 20 کیلوهرتز همزمان با تولید نفت چاه از روز اول، بازیافت نفت نسبت به بازیافت نفت در حالتی که شروع اعمال موج از روزهای پنجاه و نود باشد، به ترتیب %5/4 و %8 بیشتر شده است. بازیافت نفت درصورتی که موج در یک زمان مشخص بصورت پیوسته به مخزن اعمال شود به میزان 8/1% نسبت به حالتی که در همان زمان بصورت پالسی اعمال شود، بیشتر است .نتایج مدلسازی نشان میدهد که هرچقدر فاصله منبع تولید موج با چاه تولیدی کمتر باشد، افت فشار محدوده چاه کمتر شده و بازیافت نفت افزایش میابد.  بطوری که طبق نتایج اگر منبع تولید موج در فاصله 200 فوتی از چاه تولیدی قرار گرفته باشد، نسبت به فاصله 1800 فوتی از چاه بازیافت نفت % 1/7 افزایش میابد.


Volume 7, Issue 4 (12-2023)
Abstract

Research subject: Millions of dollars of non-renewable capital are burned in flares every year, in the oil and gas industries, which in addition to polluting the air has no income for the industry. In Iran and South Pars region, due to the presence of gas refineries, a considerable amount of gas is burned in the flares. In this research, as a comprehensive study, the technical and economic investigation of the recovery of flare gases has been discussed.
Research approach: For this purpose, Aspen Plus software was used to simulate the desired unit in the set of flares of South Pars refinery phases 22-24. The simulation consists of two recovery parts: the flare gases recovery by use of a liquid ring compressor and power generation by the heat from the combustion of the flare gases through the application of the reheat steam Rankine cycle. The profitability of the project includes naphtha cuts and liquefied gas recovered from gases sent to the flare on one hand and power generation in turbines on the other hand.
Main results: The effect of the amount of air entering the combustion chamber on the temperature of the exhaust gas was investigated. The amount of air entering the combustion chamber was determined to be 2685 tons per hour in order to obtain supercritical water vapor with a temperature of about 650 ºC and a pressure of 26 kPa in the Rankine cycle. Using the simulation results, the temperature diagram was drawn in terms of entropy, and in addition to the steam phase diagram during the cycle, the steam Rankine cycle diagram was also drawn. The results of this research showed that the designed process will produce 5365 kg/h of naphtha, 179.45 kg/h of LPG, 25903 kW, and 101124 kW power in two separate turbines, and an annual sales income of 24,782,194 $. In addition, it was shown that the investment return period of this process is equal to 2.5 months.


Volume 11, Issue 1 (6-2011)
Abstract

Repowering means addition of gas turbine unit(s) to a steam power plant in order to make use of the exhaust gas heat and to increase efficiency of the new combined cycle. There are two groups of repowering methods: partial repowering and full repowering. Full repowering is more common and is used in power plants with nearly ended useful lifetime. In this case the capital investment is considerably reduced compared with the case of making a similar combined cycle. Objective functions are per kWh electricity cost and exergy efficiency. These functions are based on important independent variables of heat recovery boiler, steam turbines, gas turbine. Finally, considering the introduced objective functions, it is tried to achieve the most optimized techno-economic characteristics for Be'sat power plant repowering cycle, using genetic algorithm optimization method with two scenarios of single and multiobjective.
Ziba Najmi, Gholamhosein Ebrahimipour,
Volume 11, Issue 3 (10-2020)
Abstract

Although biosurfactants have great advantages over chemical surfactants, their wider industrial applications have been constrained by their relatively high production cost. Using renewable, sustainable and cheap substrates such as different industrial by-products and wastes maybe decrease biosurfactant production costs. Since in different countries, there are a variety of by-products and wastes so use of these substrates rely on their types and concentrations in countries. In addition to hydrocarbon compounds, molasses has been considered as a dominant by-product in Iran. In this study, among 16 crude oil degrading isolates, strain Pseudomonas aeruginosa ZN was selected as an efficient biosurfactant producer by screening methods for detection of biosurfactant producing bacteria. For investigation of molasses concentrations effect on bacterial growth and biosurfactant production, a wide range of molasses concentrations from 2-12% (v/v) were used. This strain was able to grow and produce biosurfactant in all range of molasses concentrations while the best concentrations were 4-6%. Also, at the optimum molasses concentration, reduction of surface tension from 70 to 32-34 mN/m was observed. The concnetrations more than these values decreased the growth and production process. Acid precipitation and solvent extract (ethyl acetate: hexane) methods were carried out for recovery of biosurfactant from the culture broth, then results of spraying on developed TLC and staining fermentation broth without bacterial cells showed the two produced biosurfactants were glycolipid.

Volume 12, Issue 1 (1-2024)
Abstract

Aims: Cardiovascular disease remains highly prevalent in Tehran City, Iran, necessitating a careful consideration of the quality of life among individuals afflicted with heart disease. This study aimed to assess the effectiveness of recovery-oriented cognitive therapy on quality of life and life expectancy in cardiac patients.
Materials & Methods: This semi-experimental study employed a pre-test/post-test design in cardiovascular patients who visited the Tehran Heart Center hospital for cardiac rehabilitation in 2022-2023. Recovery-oriented cognitive therapy was used as an intervention for the experimental group (n=24), and the control group (n=30) had no intervention. Following a month-long intervention comprising two sessions per week, patients underwent reassessment at three- and six-months post-treatment. The short form 36 (SF-36) and adult hope scale-12 (AHS-12) questionnaires were used. The data was analyzed using the Bonferroni t-test, covariance-based statistics, and one-way multivariate analysis of variance (MANOVA) using the SPSS 21 software.
Findings: There were no significant differences in the quality of life and life expectancy parameters between the experimental and control groups. The quality of life and life expectancy showed consistent and significant improvement across all four measured time points
Conclusion: Recovery-oriented cognitive therapy positively affects the quality of life and life expectancy in cardiac patients.

Volume 12, Issue 4 (11-2012)
Abstract

In all of power plants, which are made only for electricity generating, more than half of fuel energy is wasted. This waste energy could be recovered by cogeneration or trigeneration systems. In this study a cogeneration combined cycle with triple pressure HRSG has been simulated. Second product was considered heat that can be generated as steam or hot water depends of intended consumption. At first, exergy and energy analysis has been carried out and potential of waste heat in power plant was determined and evaluated. By using TRR method Thermoeconomic analysis was done and cost of products calculated. At the end of this research an objective function defined and to optimize with algorithm Genetic method, some decision variables were selected. After various parameter optimizations at different situation of power plant, optimum structure specified. Results are shown at which status of power plant, producing heat and power has maximum efficiency and profitability.

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