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In this research, general performance of Radial basis function (RBF) Artificial neural networks in experimental data on effect of the NiO, WO3, TiO2,ZnO and Fe2O3 nanoparticles in different temperatures and mass fractions on the viscosity of crude oil has been studied. The morphology and stability of the nanoparticles has been analyzed by DLS and TEM analysis, the results showed that the average diameter of the nanoparticles is from 10 to 30 nm which defers for different oxide nanoparticles. The general method for calculating the optimum span of the Isotropic Gaussian function with special algorithm for learning RBF networks, has been presented. This study's results declared that the RBF artificial neural networks, because of having strong academic basis and having the ability to filter the noises, has a good performance. With increase in temperature, the ratio of the viscosity of the nanofluids decreases compering to the viscosity of the basefluid. Also with increase in nanoparticles mass fraction the related viscosity increases boldly. For temperatures higher than 50°C, the related viscosity is less than the viscosity of the basefluid.

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One of the miniaturization of heat transfer equipment is enhancing the convective heat transfer coefficient. The main aim of this study is design and producing a kind of nanofluid based on water and ethylene glycol. Graphene was synthesized via electrochemical method and its successful production was confirmed with XRD, FTIR spectrum and, SEM and TEM images. By using different amount of graphene i.e. 0.25, 0.5, 0.75, 1, 1.25, and 1.5%, water/ethylene glycol/graphene nanofluid was produced. Sodium dodecyl sulfate (SDS) was used as surfactant to improve graphene stability in the base fluid. The designed experimental setup was composed of spiral tube with constant wall temperature and equipped with flow meter and pressure and temperature indicators. Nusselt number and pressure drop were measured for pure water and compared with those obtained from theoretical relations and it was found that the setup works properly. Convective heat transfer coefficient, Nusselt number, and heat transfer rate were investigated for water/ethylene glycol (60/40 wt.%) and nanofluid with different amount of graphene using experimental setup. The results showed that by adding 1 wt.% graphene into the based fluid the convective heat transfer coefficient increased about 50% while pressure drop was also increased about 50%. Overall, the findings of this research work support the potential of water/ethylene glycol/graphene nanofluid for using in heating/cooling equipment.
 

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Abstract
Research subject: The combustion of fossil fuels to supply energy produces large amounts of carbon dioxide. Carbon dioxide emissions have led to rising global temperature and many natural disasters, including floods, hurricanes, rising sea levels, and widespread droughts, that threaten ecological systems and human life. Therefore, the uptake and removal of carbon dioxide from sources or the environment play a key role in countering the threat of global warming.
Research approach: In this study, a venturi scrubber was utilized to eliminate CO2 from the air stream on a semi-industrial scale. The effects of different parameters including inlet air flow rate to the venturi scrubber, solvent flow rate, and solvent loss during the scrubbing process were investigated on CO2 absorption by a nanofluid solvent containing iron oxide/water at the presence of tetramethylammonium hydroxide (TMAH) as a surface-active material.
Main results: The surface-active material of TMAH prevents the agglomeration of nanoparticles in the base fluid and stabilizes the fluid. The maximum efficiency of absorption and the highest molar flux of CO2 were achieved when iron oxide nanoparticles were used along with graphene nanosheets with the ratios of iron oxide nanoparticles (25%) and graphene nanosheets (75%) at the presence of TMAH surface-active material due to their nature. The reason is the better agitation (of the solution) by iron oxide nanoparticles that results in an increased displacement of graphene nanosheets. The random Brownian movements of nanoparticles create micron size eddies that increase mass transfer at the gas-liquid interface. In addition, molar flux and CO2 gas absorption efficiency decreased by increasing the concentration of nanoparticles.
Keywords: Hybrid nanofluid; Venturi scrubber; Gas absorption; Iron oxide nanoparticles; Graphene nanosheets

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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.
 

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Abstract- In the present paper, three different samples of alumina used as nanoparticles in the ethylene glycol suspension of alumina with volumetric concentration in the range . These samples have different surface properties, shape and size. The use of Al2O3/EG nanofluids as coolants in a double-tube heat exchanger has been studied under laminar flow conditions. The hot solvent inlet heat exchanger must be cooled down with a specified amount. At first, heat transfer relations between hot solvent and nanofluids as coolants have been investigated theoretically. Subsequently, heat transfer area and flow rate of coolant are optimized by using the nanofluids. In the present paper, heat transfer coefficient, overall heat transfer coefficient, friction factor, pressure drop and pumping power for Al2O3/EG nanofluids calculated.

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ABSTRACT A numerical investigation of mixed convection heat transfer with nanofluid and pure water from a heat source in a horizontal channel is performed. The walls of the channel are adiabatic and the heat source is placed at the bottom wall of the channel. Free flow at cold temperature enters channel and takes heat from heat source. Discretization of the continuity, momentums and energy equations are achieved through a finite volume method and solved with SIMPLE method. The Brownian motion of nanoparticles is simulated to determine the thermal conductivity of the nanofluid.The results show that using the nanofluid caused to heat diffusion and average temperature of source to increase. Also, increase in solid volume fraction causes increase in heat transfer especially at high Reynolds number. It is understand that with increase in ratio of length to height of source in its constant area, heat transfer decreases first and then increases.

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Klebsiella pneumoniae is a gram-negative bacillus of the Enterobacteriaceae family. Despite being part of the natural human microflora, this is an opportunistic pathogen and a major cause of nosocomial infections. The increased emergence of multidrug resistance in Klebsiella pneumoniae has limited the treatment options for this bacterium. Carbon nanotubes (CNT), by improving the stability and solubulity of drugs, could increase the effectiveness of drugs for treatment. The aim of this study is to investigate the antibacterial effect of nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) on Klebsiella pneumoniae isolated from clinical specimens. For the strain confirmation, biochemical ,API20E kit, and additional differential tests were performed, and antibiotic susceptibility test was performed by the disk diffusion method. The studied strain showed a resistance to all antibiotics such as cefepime.The minimum inhibitory concentration (MIC) was determined using the antibiotic micro dilution method. The MIC was determined in five effect modes including antibiotic (Ab), nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) , nanofluid containing multi-walled carbon nanotubes (CNT-NF) ,Ab in combination with f-CNT-NF and Ab with CNT-NF. Nevertheless the individual effects of 10 µg mL^-1 cefepime or 80 µg of nanofluid with f-CNT-NF did not inhibit the growth of the bacteria, but the co-administration of 10 µg mL^-1 cefepime with 80 µg of the f-CNT-NF could inhibit the bacteria`s growth. It was concluded that f-CNT-NF could be more effective in drug delivery at lower concentrations than the free state, which could be used as a tool for optimal drug delivery.

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Water-Alumina natural convection heat transfer in an inclined L shape cavity ABSTRACT A numerical investigation of water-alumina natural convection laminar flow in an inclined L shape cavity is performed. Two wall of the cavity are hot with the temperature of Th, two walls are cold with the temperature of Tc , and two other walls are thermally adiabatic. The two dimensional continuity, momentums and energy equations are solved numerically with a finite volume approach using the well known SIMPLE algorithm. The influence of pertinent parameters such as Rayleigh number, Ra, solid volume fraction, , inclination angle, , and cavity aspect ratio, A, on the fluid flow, fluid temperature and cavity heat transfer characteristics is studied. The results indicate that nanofluid with higher nanoparticles has better performance. The results also show that the inclination angle has a significant effect on the heat transfer performance at high Rayleigh numbers. Keywords: Natural convection, nanofluid, L shape cavity, Rayleigh number.

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Abstract- This paper presents the results of a numerical study on the natural convection in a right triangular enclosure filled with a water- Cu nanofluid in presence of a constant magnetic field. A heat source embedded on the bottom wall of enclosure, the inclined wall is cold and the other walls are adiabatic. Discretization of the governing equations are achieved through a finite volume method and solved with SIMPLE algorithm. The effects of parameters such as the Reyleigh number, the solid volume fraction, the Hartman number, length and location of heat source on flow and temperature fields and the heat transfer rate have been examined. The results show that increasing of Hartman number caused decreasing velocity of flow and heat transfer. Also, increase in solid volume fraction causes increase in heat transfer but its change in different Reyleigh number and Hartman number is not same. Therefore, the location of heat source in bottom of enclosure affects on the rate of heat transfer from enclosure.

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Abstract- Mixed convection flow of a water-copper nanofluid in a channel under magnetic field effects has been numerically investigated. The fluid flow and temperature fields as well as the heat transfer rate have been determined by solving the Navier-Stocks and energy equations. In this study, the effects of various parameters such as the Richardson number, the Hartmann number, the solid volume fraction and the channel angle on the thermal performance of the channel have been examined. The results showed that at high Richardson numbers, the heat transfer rate decreased as the Hartman number increased. It was also found that the heat transfer rate increased as the Richardson number, the solid volume fraction and the channel angle increased. The maximum flow reversal was observed to occur in a vertical channel.

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In this research, validity of temperature-independent thermophysical properties assumption of water-Al203 nanofluid in natural convection problems within the enclosures is investigated. The numerical results are obtained utilizing an in-house finite volume code based on the SIMPLE algorithm. In order to do the validation the numerical results and those of existing correlations are compared. In order to evaluate the thermal performance of the enclosure, the average Nusselt number on the hot side wall in both temperature-independent and dependent cases is compared Results show that, in the all considered solid volume fractions, the difference in the Nusselt number in the case of temperature-independent properties is less than 10 percent in comparison with the case in which the properties are temperature-dependent when temperature difference is less than 5 ○C. As the temperature increases, the difference between Nusselt number in both cases increases and the effect of increase in solid volume fraction is to increase this difference. Results also show that the difference between these two cases is dependent solely on temperature differences between the hot and cold walls regardless of the temperature they have.

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Abstract- The present study aims to investigate numerically the natural convection of various nanofluids inside a square enclosure with a central heat source at different aspect ratio. Also, some correlations are presented in order to calculate the Nusselt number in terms of Rayleigh number and volume fraction of nanoparticles. The heat source and cavity walls are kept at constant temperatures of Th and Tc, respectively. The nanofluids are considered to be water as the base fluid and different nanoparticles such as Cu, CuO, Ag, Al2O3, or Tio2. To discretize the governing equations, the control volume method and SIMPELER algorithm have been employed. The study has been carried out for aspect ratios from 0.2 to 0.8, Rayleigh numbers from 1e3 to 1e6 and the volume fractions of nanoparticles ranging in 0-0.05. The results indicated that the Nusselt number increases with increasing the volume fraction of nanoparticles as well as the aspect ratio. Furthermore, by increasing the Rayleigh number, some eddies, of kind of Rayleigh-Benard, are developed in the space between the heat source and the upper wall of the enclosure. Based on the obtained results, several correlations with high accuracy have been present in order to evaluate the Nusselt number.

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In this paper, heat transfer in a sinusoidal channel filled with nanofluid under magnetic field effect is investigated numerically. The magnetic field transversely applied to the channel. Water as a base fluid and copper as nano particles were considered .The Maxwell-Garnetts model and Brinkman model for heat conduction coefficient and dynamic viscosity were used respectively. The effects of changing some parameters such as shape ,volume fraction , Hartmann number and Reynods number were considered. The results show that increasing in all mentioned parameters lead to increasing in Nusselt number. Volume fraction is mainly affect on maximum local Nusselt number in each channel’s wave while Hartmann number is affected minimum and maximum Nusselt number.

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Developing the high performance electrical devices requires high capacity heat transfer manners, which could be the pulsating heat pipes (PHPs). PHPs have a better performance in compare with conventional heat pipes (HPs), besides, they can be used to improve cooling systems for electrical devices, in future. There are some other applications for PHPs in other industries as heat transfer converters, either. The effect of the evaporator’s length on the PHPs’ performance is investigated experimentally by hiring a five turns PHPs and ferrofluid as set-up and working nanofluid, respectively. The results show that PHPs’ performance is enhanced by increasing the evaporator’s length.

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Heat pipe is an effective device for heat transferring. Using nanofluid as working fluid can significantly increase heat pipe thermal performance. But rate of the performance improvement, is dependent on parameters of the suspended nanoparticles in nanofluid. In this article, for the first time by considering nanoparticle volume fractions and diameters as design variables and the difference between the wall temperature of evaporator and condenser and liquid pressure drop as objective functions, the heat pipe performance has optimized. The used heat pipe is a cylindrical heat pipe with nanofluid as working fluid. Heat pipe thermal performance while using nanofluid has modeled by CFD method and then GEvoM has used to relate between design variables and objective functions. Using the modified NSGAII approach, pareto front has plotted and the values of recommended optimum points has obtained by mapping method. Recommended design points unveil interesting and important optimal design principles that would not have been obtained without the use of a multi-objective optimization approach.

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This paper studies the effects of soluble cutting fluid-based CuO Nanofluid on machining force and surface roughness in turning of hardened AISI 4340 tool steel. These influences, Moreover, are compared with the outputs of similar tests through dry and soluble cutting fluid. The obtained results showed 1% volume fraction of CuO Nanoparticles added to soluble oil as cutting fluid was considerably reduced machining force and surface roughness in comparison to soluble cutting oil and dry. The investigations indicated that CuO Nanofluid reduced surface roughness and machining force by 49% and 24% respectively. Moreover, the results illustrated that the lowest surface roughness obtained in cutting speed 250 m/min, feed rate 0.1 mm/rev and cutting nanofluid.

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In this research, two effective techniques to increase mixed convection heat transfer rate within an enclosure subjected to a transverse magnetic field are studied. In order to increase the heat transfer rate, the addition of Al2O3 nanoparticles is concerned as the first strategy and the change in magnetic field inclination angle is considered as the second. In this study, the left and right sides of the enclosure are kept at constant temperature while the top and bottom walls are adiabatic. In this work, the results are obtained with an in-house finite volume code. To validate the code, the results of the present code are compared to that of an existing correlation as well as those of previous works and good agreements are observed. In the present work, Richardson number varies from Ri=0.05 to Ri=50. Results show that the addition of solid particles may increase or decrease the heat transfer rate whereas the increase in magnetic field inclination angle mostly leads to increase in the heat transfer rate.

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In this paper, the natural convection of water-Al2O3 nanofluid in a square enclosure exposed to a magnetic field is numerically investigated. The enclosure is bounded by two isothermal vertical walls at different temperaturesof Th and Tc.The two horizontals walls of the enclosure are thermally insulated. A vertical plate (membrane separator) with a negligible thickness and a variable height is located in the middle of the chamber. Discretization of the governing equations are achived through a finit method and are solved using the SIMPLE algorithm. Based on the results of the numerical solution, the effects of the relevant parameters such as the dimensionless height of the membrane separator, Rayleigh number, the solid volume fraction and the Hartmann number on the flow field and the heat transfer rate are investigated. The results show that the heat transfer rate decreases with an increase of the dimensionless height of the membrane separator and an increase of the Hartmann number. The heat transfer rate, however, increases as the Rayleigh number increases. Depending on the Rayleigh number, the thermal performance of the enclosure is either improved or deteriorated as the solid volume fraction is increased.

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In this work, mixed convection of Cu-water nanofluid in a trapezoidal enclosure with heat source on lateral walls has been numerically investigated. Vertical walls of the enclosure are kept at constant temperatures of Th and Tc, while horizontal walls are insulated. The mixed convection flow has been generated by passing the fluid through the enclosure and natural convection has been, also, investigated by holding the left wall at a temperature higher than the right wall. In order to examine the effect of the ports position, two cases were considered. Comparison between the results indicates that the rate of heat transfer is higher when the inlet port is near the cold wall than the hot wall. The results have been presented for various volume fractions, Richardson and Reynolds numbers. It was observed that for the considered Reynolds numbers and Richardson number, at a given Reynolds number and solid volume fraction, the Nusselt number increases with increasing the Richardson number. Moreover, at a given Richardson number and solid volume fraction, increasing the Reynolds number results in an increase in the Nusselt number. For the higher Richardson and Reynolds numbers, the nanofluid has more effect on the increase of the heat transfer performance.

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Heat transfer of Alumina/water nanofluids in a uniform-temperature porous pipe has been investigated in a wide range of Reynolds number, i.e. 700<Re<5000. Investigation of force convective heat transfer of nanofluids in a porous pipe with uniform wall temperature has not been considered completely in the literature. In this experimental study, Alumina nanofluids with different volume fractions have been completely employed. By measuring the nanofluid temperatures, the Nusslet numbers have been reported as a function of the Reynolds number. Also, the pressure drop of nanofluids inside the porous pipe has been measured. The accuracy of the experimental results has been also validated by the presented theoretical formulas in the literature. The result shows a considerable increase in the Nusslet number by using nanofluids instead of water. Convective heat transfer of a porous pipe has been also studied as a novel method to increase the heat transfer rate. The related results show a significant increase in the heat transfer in the presence of porous medium. Both heat transfer and pressure drop of nanofluids in the porous pipe have been also reported and discussed.