AIM:To investigate the effect of using base-out prisms on nystagmus,visual acuity and contrast sensitivity in patients with albinism.METHODS:In this interventional study,patients with albinism who had nystagmus were e...AIM:To investigate the effect of using base-out prisms on nystagmus,visual acuity and contrast sensitivity in patients with albinism.METHODS:In this interventional study,patients with albinism who had nystagmus were enrolled.A comprehensive eye exam was conducted,which included refraction,assessment of far and near vision acuity,and contrast sensitivity measurements.To check for the nystagmus,a videonystagmography was used.The tests were carried out in three modes:without any correction,with optical correction,and with correction using base-out prisms in three different powers,including 4,6,and 8 prism diopters.RESULTS:Totally 23 patients with average age of 28.65±12.13 were examined.It was found that the use of optical correction and optical correction with prisms resulted in a statistically significant improvement in both far(at least:P<0.006)and near visual acuity(at least:P<0.001 except for prism 8;P<0.02).In addition,contrast sensitivity significantly improved at all low and medium frequencies except for correction with prism 8 in frequency 1.5(at least:P<0.01 except for prism 4,frequency 6;P=0.04).no significant improvement was observed in the evaluation of nystagmus characteristics.CONCLUSION:Optical correction with a prism can improve visual acuity and some spatial frequencies,but failed to improve nystagmus parameters.展开更多
Sand production from loosely consolidated reservoirs is one of the critical issues in the oil and gas in-dustry all around the world that can cause many problems,such as erosion of surface and well equip-ment,sand acc...Sand production from loosely consolidated reservoirs is one of the critical issues in the oil and gas in-dustry all around the world that can cause many problems,such as erosion of surface and well equip-ment,sand accumulation in wells and operation facilities,buckling of casing in cased-hole wells and well productivity reduction.Sand production control methods include restrictive production rate,mechanical methods(slotted liner,wire-wrapped screen,pre-packed screen,frac-pack,gravel pack,high-rate water pack)and chemical consolidation that chemical method is considered for more effectiveness in sand production alleviation due to increasing formation strength in near wellbore region.This review provides an overview on the laboratory and filed operation investigations of chemical remedy for sand production.Some used chemical agents and more common laboratory tests for evaluating the chemical performance in sand consolidation are introduced in this paper.Furthermore,the results of field operations and in-jections of chemicals into the desired formation are also reported.These results show that the chemical sand consolidation is more effective in newly perforated wells which have no sand production experi-ence and have a production history of less than two years.Finally,it was concluded that the main challenges in applying this method are permeability and capillary force reduction around the wellbore and selective injection into the targeted formation layers.展开更多
Nanofluids have novel characteristics that make them potentially useful for different applications.Realizing modest mass transfer enhancement in conventional nanofluids,in this study,mass-transfer of carbon dioxide in...Nanofluids have novel characteristics that make them potentially useful for different applications.Realizing modest mass transfer enhancement in conventional nanofluids,in this study,mass-transfer of carbon dioxide in pure water and water-based nanofluids dispersed with silica nanoparticles at different initial pressures up to 15 MPa and at temperatures of 35℃ and 45℃ was investigated.Deionized water and two nanofluids at different concentrations with volume of 150 cm^(3) were used for this purpose.CO_(2) was brought in contact with each solution in a pressure-volume-temperature(PVT)cell with no mixer.Additionally,carbon dioxide diffusion coefficients at different pressures were estimated based on Fick's law.The obtained results demonstrated that water/silica nanofluid with 0.5 wt%and 0.1 wt%increased the carbon dioxide diffusion coefficient up to 39.2%and 11.9%compared to that in pure distilled water,respectively.Moreover,it was observed that the measured diffusion coefficient of carbon dioxide inwater increased with temperature rise from 35℃ to 45℃ at constant pressure.However,it could be seen that,the diffusion coefficient decreased with pressure at constant temperature.It was concluded that among the enhancement mechanisms of nanoparticles,(i.e.grazing effect and Brownian motion),Brownian motion would play the main role in mass transfer enhancement.展开更多
The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longit...The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longitudinal size shorter than the plasma wavelength, λp, instead of a periodic plasma wave, a cavity free from cold plasma electrons, called a bubble, is formed behind the laser pulse. An intense charge separation electric field inside the moving bubble can capture the electrons at the base of the bubble and accelerate them with a narrow energy spread. In the nonlinear bubble regime, due to localized depletion at the front of the pulse during its propagation through the plasma, the phase shift between carrier waves and pulse envelope plays an important role in plasma response. The carrier–envelope phase（CEP） breaks down the symmetric transverse ponderomotive force of the laser pulse that makes the bubble structure unstable. Our studies using a series of two-dimensional（2D） particle-in-cell（PIC） simulations show that the frequency-chirped laser pulses are more effective in controlling the pulse depletion rate and consequently the effect of the CEP in the bubble regime. The results indicate that the utilization of a positively chirped laser pulse leads to an increase in rate of erosion of the leading edge of the pulse that rapidly results in the formation of a steep intensity gradient at the front of the pulse. A more unstable bubble structure, the self-injections in different positions, and high dark current are the results of using a positively chirped laser pulse. For a negatively chirped laser pulse, the pulse depletion process is compensated during the propagation of the pulse in plasma in such a way that results in a more stable bubble shape and therefore, a localized electron bunch is produced during the acceleration process. As a result, by the proper choice of chirping, one can tune the number of self-injected electrons, the size of accelerated bunch and its energy spectrum to the va展开更多
Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been conside...Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been considered as one of the multi-objective EOR techniques to store CO2 in the hydrocarbon bearing formations as well as improving oil recovery efficiency.During CWI process,as the reservoir pressure declines,the dissolved CO2 in the oil phase evolves and gas nucleation phenomenon would occur.As a result,it can lead to oil saturation restoration and subsequently,oil displacement due to the hysteresis effect.At this condition,CO2 would act as insitu dissolved gas into the oil phase,and play the role of an artificial solution gas drive(SGD).In this study,the effect of SGD as an extra oil recovery mechanism after secondary and tertiary CWI(SCWI-TCWI)modes has been experimentally investigated in carbonate rocks using coreflood tests.The depressurization tests resulted in more than 25%and 18%of original oil in place(OOIP)because of the SGD after SCWI and TCWI tests,respectively.From the ultimate enhanced oil recovery point of view,the efficiency of SGD was observed to be more than one-third of that of CWI itself.Furthermore,the pressure drop data revealed that the system pressure depends more on the oil production pattern than water production.展开更多
Purpose:The objective of this scoping review was to summarize systematically the available literature investigating the relationships between the coronavirus disease 2019(COVID-19)pandemic and movement behaviors(physi...Purpose:The objective of this scoping review was to summarize systematically the available literature investigating the relationships between the coronavirus disease 2019(COVID-19)pandemic and movement behaviors(physical activity,sedentary behavior,and sleep)of school-aged children(aged 511 years)and youth(aged 1217 years)in the first year of the COVID-19 outbreak.Methods:Searches for published literature were conducted across 6 databases on 2 separate search dates(November 25,2020,and January 27,2021).Results were screened and extracted by 2 reviewers(DCP and KR)independently,using Covidence.Basic numeric analysis and content analysis were undertaken to present thematically the findings of included studies according to the associated impact on each movement behavior.Results:A total of 1486 records were extracted from database searches;of those,150 met inclusion criteria and were included for analysis.Of 150 articles,110 were empirical studies examining physical activity(n=77),sedentary behavior/screen time(n=58),and sleep(n=55).Results consistently reported declines in physical-activity time,increases in screen time and total sedentary behavior,shifts to later bed and wake times,and increases in sleep duration.The reported impacts on movement behaviors were greater for youth than for children.Conclusion:The COVID-19 pandemic is related to changes in the quantity and nature of physical activity,sedentary behavior,and sleep among children and youth.There is an urgent need for policy makers,practitioners,and researchers to develop solutions for attenuating adverse changes in physical activity and screen time among children and youth.展开更多
Imbibition of water,as wetting phase in oil-wet fractured carbonate reservoirs,plays a key role in fluid flow between matrix and fracture system.The type of injected seawater and its chemistry would profoundly influen...Imbibition of water,as wetting phase in oil-wet fractured carbonate reservoirs,plays a key role in fluid flow between matrix and fracture system.The type of injected seawater and its chemistry would profoundly influence the imbibition process.In this study,the impact of smart water(a brine that its ions have been adjusted to facilitate oil recovery)and low salinity water on co-and counter-current imbibition processes for oil-wet carbonate cores has been experimentally investigated.The results show an increase of about 10% in oil recovery for co-and counter-currents for smart seawater imbibition compared to that of low salinity seawater.In addition,as a result of the influence of co-and counter-current on each other,by co-current removal from one core face,the countercurrent in the other face would be intensified by as much as about 75%.A close examination of different lengths(5,7 and 9 cm)of carbonate cores with the same permeability revealed that by decreasing porous medium length,the amount of counter-current producing oil would be decreased so that in the 5 cm core,counter current oil production will not happen.For similar core lengths by increasing permeability,the share of counter current flow would be decreased approximately 18% since the capillary pressure could not overcome non-wetting phase viscous forces.Considering the role of matrix length along with a modified brine(which is designed according to the matrix mixture)strengthen the relevant mechanisms to have more oil production so that the higher thickness of matrix causes the higher amount of co-current oil producing and consequently more total recovery.展开更多
Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration,interfacial tension(IFT)reduction,oil vi...Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration,interfacial tension(IFT)reduction,oil viscosity reduction,formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation.To the best of the authors’ knowledge,the synthesis of a new nanocomposite has been studied in this paper for the first time.It consists of nanoparticles of both SiO2 and Fe3O4.Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs.According to the previous studies,Fe3O4 has been used in the prevention or reduction of asphaltene precipitation and SiO2 has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery.According to the experimental results,the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually.According to the results obtained for the use of this nanocomposite,understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.展开更多
The effect of upstream velocity pertuibations on the response of a premixed flame was investigated in terms of the flame transfer function dependency on excitation frequency.In this study,the assumption of constant fl...The effect of upstream velocity pertuibations on the response of a premixed flame was investigated in terms of the flame transfer function dependency on excitation frequency.In this study,the assumption of constant flame speed was extended and the effect of flame speed development was considered;i.e.,the flame speed would grow with the time after ignition or with the distance from a flame-holder.In the present study,the kinematics of a conical flame was investigated by linearization of the front tracking equation of flame to uniform and convected fluctuations of the flow velocity and the response was compared with that of a V-shaped flame and the experimental data in the previous studies.The results show that the effect of flame speed development could influence a decreasing gain and increase the phase of the flame response to the uniform velocity oscillations in low and moderate frequencies.Comparing the variations in the gain of flame response upon normalized frequency,show that a conical flame has lower values than the V-flame.In other woods,these flames might be less susceptible to combustion instabilities than the V-flames.Furthennore,the variations in phase of the V-flames responses,which show a quasi-linear behavior with normalized frequency,have higher values than the saturated behavior in phase of the conical flame responses.Also,considering that the flame speed development induces an increase in the gain and phase of the conical flame response to the convected velocity oscillations in certain frequencies;because the developed flame front has longer length in comparison to the flame front in constant flame speed model.Therefore,the flame length may be longer than convective wavelength and the heat release would be generated in different points of the flame;consequently the flow oscillations might exert a stronger impact on the unsteady heat release fluctuations.展开更多
Background: Drug abuse could cause complications;infection and overdose are the most prevalent of them. Unreliable history of addicted patients also makes the diagnosis difficult and leads to delayed treatment and poo...Background: Drug abuse could cause complications;infection and overdose are the most prevalent of them. Unreliable history of addicted patients also makes the diagnosis difficult and leads to delayed treatment and poor prognosis. Early recognition and prompt treatment are required to minimize the destructive damage. To our knowledge, there is not any previous report of bilateral eye injection among drug abusers, causing traumatic endophthalmitis in the English literature and our report helps ophthalmologists to think about rare sources of endophthalmitis. Aim: The aim is to emphasize the importance of considering exogenous endophthalmitis in I.V. drug users who abuse drugs. Methods: A 40-year-old I.V. drug user man was referred complaining a history of the pain, redness and impaired vision of both eyes from three days ago. Perilimbal injection and anterior chamber cellular reaction were present in both eyes. Both corneas were hazy;corneal edema, abscess, sealed corneal lacerations and dull red reflex were visible in both eyes. Results: After an ultrasonography based on the suspicion of endophthalmitis, anterior chamber and vitreous aspiration and intravitreal injection of vancomycin 1 mg and ceftazidime 2.25 mg were performed. The right eye rapidly deteriorated and was eviscerated two days later and the left eye had a good response to medications. Conclusion: This report illustrates that the orbit can be a potential site of drug injection and endophthalmitis should be considered in individuals who abuse drugs.展开更多
In this study,the impacts of solutal Marangoni phenomenon on multiphase flow in static and micromodel geometries have experimentally been studied and the interactions between oil droplet and two different alkaline sol...In this study,the impacts of solutal Marangoni phenomenon on multiphase flow in static and micromodel geometries have experimentally been studied and the interactions between oil droplet and two different alkaline solutions(i.e.MgS04 and Na_2 CO_3) were investigated.The static tests revealed that the Marangoni convection exists in the presence of the alkaline and oil which should carefully be considered in porous media.In the micromodel experiments,observations showed that in the MgS04 flooding,the fluids stayed almost stationary,while in the Na2 C03 flooding,a spontaneous movement was detected.The changes in the distribution of fluids showed that the circular movement of fluids due to the Marangoni effects can be effective in draining of the unswept regions.The dimensional analysis for possible mechanisms showed that the viscous,gravity and diffusion forces were negligible and the other mechanisms such as capillary and Marangoni effects should be considered in the investigated experiments.The value of the new defined Marangoni/capillary dimensionless number for the Na2 C03 solution was orders of magnitude larger than the MgS04 flooding scenario which explains the differences between the two cases and also between different micromodel regions.In conclusion,the Marangoni convection is activated by creating an ultra-low IFT condition in multiphase flow problems that can be profoundly effective in increasing the phase mixing and microscopic efficiency.展开更多
In this paper,a new robust approach based on Least Square Support Vector Machine(LSSVM)as a proxy model is used for an automatic fractured reservoir history matching.The proxy model is made to model the history match ...In this paper,a new robust approach based on Least Square Support Vector Machine(LSSVM)as a proxy model is used for an automatic fractured reservoir history matching.The proxy model is made to model the history match objective function(mismatch values)based on the history data of the field.This model is then used to minimize the objective function through Particle Swarm Optimization(PSO)and Imperialist Competitive Algorithm(ICA).In automatic history matching,sensitive analysis is often performed on full simulation model.In this work,to get new range of the uncertain parameters(matching parameters)in which the objective function has a minimum value,sensitivity analysis is also performed on the proxy model.By applying the modified ranges to the optimization methods,optimization of the objective function will be faster and outputs of the optimization methods(matching parameters)are produced in less time and with high precision.This procedure leads to matching of history of the field in which a set of reservoir parameters is used.The final sets of parameters are then applied for the full simulation model to validate the technique.The obtained results show that the present procedure in this work is effective for history matching process due to its robust dependability and fast convergence speed.Due to high speed and need for small data sets,LSSVM is the best tool to build a proxy model.Also the comparison of PSO and ICA shows that PSO is less time-consuming and more effective.展开更多
Nigella sativa L. (Black seed), is a traditional herbal medicine that has been used for many purposes. The present study was designed to investigate the effects of hydro-alcoholic extract of nigella sativa L. (NS) on ...Nigella sativa L. (Black seed), is a traditional herbal medicine that has been used for many purposes. The present study was designed to investigate the effects of hydro-alcoholic extract of nigella sativa L. (NS) on performance of Forced Swimming Test (FST), blood biochemical parameters related to fatigue and thyroid functions. Therefore, Blood Urea Nitrogen (BUN), Creatine Kinase (CK), Lactic Dehydrogenase (LDH), and Total Protein (TP), triiodothyronine T3, thyroxin T4 and TSH tests were investigated. Thirty five male adult mice were randomly divided into five groups: three NS-fed groups, one fluoxetine treated group and one control group. Three NS experimental groups received hydro-alcoholic extract of NS at doses of 50, 100 and 200 mg/kg orally for two weeks. Immobility time decreased in all NS groups compared with control group. Administration of NS significantly increased the concentration of T3 and T4 of the treatment groups. On the contrary, the amount of BUN, CK, LDH, TP and TSH decreased. In conclusion, black seed extract at the experimented doses showed anti-depressant, anti-fatigue and hyperthyroid effects.展开更多
In this article, we introduce the concept of entropy functional for continuous systems on compact metric spaces, and prove some of its properties. We also extract the Kolmogorov entropy from the entropy functional.
By comparing numerical simulation results of single-porosity and dual-porosity models,the significant effect of reinfiltration to naturally fractured reservoirs was confirmed.A new governing equation was proposed for ...By comparing numerical simulation results of single-porosity and dual-porosity models,the significant effect of reinfiltration to naturally fractured reservoirs was confirmed.A new governing equation was proposed for oil drainage in a matrix block under the reinfiltration process.Utilizing inspectional analysis,a dimensionless equation suitable for scaling of recovery curves for matrix blocks under reinfiltration has been obtained.By the design of experiments,test cases with different rock and fluid properties were defined to confirm the scope of the presented equation.The defined cases were simulated using a realistic numerical simulation approach.This method can estimate the oil amount getting into the matrix block through reinfiltration,help simulate the oil drainage process in naturally fractured reservoirs accurately,and predict the recovery rate of matrix block in the early to middle periods of production.Using the defined scaling equation in the dual-porosity model can improve the accuracy of the predicted recovery rate.展开更多
Terpenoids are novel natural products isolated from mastic gum.Mastic gum was obtained from the Pistacia Lentiscus tree.Scientific investigations have documented medical and pharmacological properties of mastic gum su...Terpenoids are novel natural products isolated from mastic gum.Mastic gum was obtained from the Pistacia Lentiscus tree.Scientific investigations have documented medical and pharmacological properties of mastic gum such as memory enhancement,antifungal,and antibacterial activities.It was astonishing to study the possible interaction of mastic gum extract with microtubule proteins which are involved in memory and consciousness since the administration of mastic gum is evidenced in the improvement of brain functions.Since a number of studies have demonstrated the effect of microtubule dynamics on mammals'memory,in this study,we investigated the effect of Oxygenated Sesquiterpenes(OST)on microtubule polymerization in vitro.OST was purified from the ethanolic extract of mastic gum.The results revealed that OST induces microtubule polymerization;however,microtubule depolymerization was not affected and fluorometric assays showed conformational changes of tubulin in the presence of OST.We interestingly found that colchicine was unable to inhibit MT assembly in the presence of OST and OST was solely more efficient than the combination of OST with paclitaxel for elevating microtubule polymerization rate.We hope that OST could be a promising agent for memory enhancement and the treatment of neurodegenerative diseases as a novel tubulin-binding compound.展开更多
Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery.Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tensi...Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery.Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tension reduction, impulsive emulsion formation and wettability alteration of porous media. The presence of dispersed nanoparticles in injected fluids would enhance the recovery process through their movement towards oil–water interface. This would cause the interfacial tension to be reduced. In this research, the effects of different types of nanoparticles and different nanoparticle concentrations on EOR processes were investigated. Different flooding experiments were investigated to reveal enhancing oil recovery mechanisms. The results showed that nanoparticles have the ability to reduce the IFT as well as contact angle, making the solid surface to more water wet. As nanoparticle concentration increases more trapped oil was produced mainly due to wettability alteration to water wet and IFT reduction. However, pore blockage was also observed due to adsorption of nanoparticles, a phenomenon which caused the injection pressure to increase. Nonetheless, such higher injection pressure could displace some trapped oil in the small pore channels out of the model. The investigated results gave a clear indication that the EOR potential of nanoparticle fluid is significant.展开更多
Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To a...Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To achieve appropriate ultimate oil recovery in these reservoirs,a water-based enhanced oil recovery method must be capable of altering the wettability of matrix blocks.Previous studies showed that carbonated water can alter wettability of carbonate oil-wet rocks toward less oil-wet or neutral wettability conditions,but the degree of modification is not high enough to allow water to imbibe spontaneously into the matrix blocks at an effective rate.In this study,we manipulated carbonated brine chemistry to enhance its wettability alteration features and hence to improve water imbibition rate and ultimate oil recovery upon spontaneous imbibition in dolomite rocks.First,the contact angle and interfacial tension(IFT)of brine/crude oil systems were measured for several synthetic brine samples with different compositions.Thereafter,two solutions with a significant difference in WAI(wettability alteration index)but approximately equal brine/oil IFT were chosen for spontaneous imbibition experiments.In the next step,spontaneous imbibition experiments at ambient and high pressures were conducted to evaluate the ability of carbonated smart water in enhancing the spontaneous imbibition rate and ultimate oil recovery in dolomite rocks.Experimental results showed that an appropriate adjustment of the imbibition brine(i.e.,carbonated smart water)chemistry improves imbibition rate of carbonated water in oil-wet dolomite rocks as well as the ultimate oil recovery.展开更多
Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.Th...Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.展开更多
文摘AIM:To investigate the effect of using base-out prisms on nystagmus,visual acuity and contrast sensitivity in patients with albinism.METHODS:In this interventional study,patients with albinism who had nystagmus were enrolled.A comprehensive eye exam was conducted,which included refraction,assessment of far and near vision acuity,and contrast sensitivity measurements.To check for the nystagmus,a videonystagmography was used.The tests were carried out in three modes:without any correction,with optical correction,and with correction using base-out prisms in three different powers,including 4,6,and 8 prism diopters.RESULTS:Totally 23 patients with average age of 28.65±12.13 were examined.It was found that the use of optical correction and optical correction with prisms resulted in a statistically significant improvement in both far(at least:P<0.006)and near visual acuity(at least:P<0.001 except for prism 8;P<0.02).In addition,contrast sensitivity significantly improved at all low and medium frequencies except for correction with prism 8 in frequency 1.5(at least:P<0.01 except for prism 4,frequency 6;P=0.04).no significant improvement was observed in the evaluation of nystagmus characteristics.CONCLUSION:Optical correction with a prism can improve visual acuity and some spatial frequencies,but failed to improve nystagmus parameters.
文摘Sand production from loosely consolidated reservoirs is one of the critical issues in the oil and gas in-dustry all around the world that can cause many problems,such as erosion of surface and well equip-ment,sand accumulation in wells and operation facilities,buckling of casing in cased-hole wells and well productivity reduction.Sand production control methods include restrictive production rate,mechanical methods(slotted liner,wire-wrapped screen,pre-packed screen,frac-pack,gravel pack,high-rate water pack)and chemical consolidation that chemical method is considered for more effectiveness in sand production alleviation due to increasing formation strength in near wellbore region.This review provides an overview on the laboratory and filed operation investigations of chemical remedy for sand production.Some used chemical agents and more common laboratory tests for evaluating the chemical performance in sand consolidation are introduced in this paper.Furthermore,the results of field operations and in-jections of chemicals into the desired formation are also reported.These results show that the chemical sand consolidation is more effective in newly perforated wells which have no sand production experi-ence and have a production history of less than two years.Finally,it was concluded that the main challenges in applying this method are permeability and capillary force reduction around the wellbore and selective injection into the targeted formation layers.
基金The authors are grateful to the Shiraz University for supporting this research.
文摘Nanofluids have novel characteristics that make them potentially useful for different applications.Realizing modest mass transfer enhancement in conventional nanofluids,in this study,mass-transfer of carbon dioxide in pure water and water-based nanofluids dispersed with silica nanoparticles at different initial pressures up to 15 MPa and at temperatures of 35℃ and 45℃ was investigated.Deionized water and two nanofluids at different concentrations with volume of 150 cm^(3) were used for this purpose.CO_(2) was brought in contact with each solution in a pressure-volume-temperature(PVT)cell with no mixer.Additionally,carbon dioxide diffusion coefficients at different pressures were estimated based on Fick's law.The obtained results demonstrated that water/silica nanofluid with 0.5 wt%and 0.1 wt%increased the carbon dioxide diffusion coefficient up to 39.2%and 11.9%compared to that in pure distilled water,respectively.Moreover,it was observed that the measured diffusion coefficient of carbon dioxide inwater increased with temperature rise from 35℃ to 45℃ at constant pressure.However,it could be seen that,the diffusion coefficient decreased with pressure at constant temperature.It was concluded that among the enhancement mechanisms of nanoparticles,(i.e.grazing effect and Brownian motion),Brownian motion would play the main role in mass transfer enhancement.
文摘The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longitudinal size shorter than the plasma wavelength, λp, instead of a periodic plasma wave, a cavity free from cold plasma electrons, called a bubble, is formed behind the laser pulse. An intense charge separation electric field inside the moving bubble can capture the electrons at the base of the bubble and accelerate them with a narrow energy spread. In the nonlinear bubble regime, due to localized depletion at the front of the pulse during its propagation through the plasma, the phase shift between carrier waves and pulse envelope plays an important role in plasma response. The carrier–envelope phase（CEP） breaks down the symmetric transverse ponderomotive force of the laser pulse that makes the bubble structure unstable. Our studies using a series of two-dimensional（2D） particle-in-cell（PIC） simulations show that the frequency-chirped laser pulses are more effective in controlling the pulse depletion rate and consequently the effect of the CEP in the bubble regime. The results indicate that the utilization of a positively chirped laser pulse leads to an increase in rate of erosion of the leading edge of the pulse that rapidly results in the formation of a steep intensity gradient at the front of the pulse. A more unstable bubble structure, the self-injections in different positions, and high dark current are the results of using a positively chirped laser pulse. For a negatively chirped laser pulse, the pulse depletion process is compensated during the propagation of the pulse in plasma in such a way that results in a more stable bubble shape and therefore, a localized electron bunch is produced during the acceleration process. As a result, by the proper choice of chirping, one can tune the number of self-injected electrons, the size of accelerated bunch and its energy spectrum to the va
文摘Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been considered as one of the multi-objective EOR techniques to store CO2 in the hydrocarbon bearing formations as well as improving oil recovery efficiency.During CWI process,as the reservoir pressure declines,the dissolved CO2 in the oil phase evolves and gas nucleation phenomenon would occur.As a result,it can lead to oil saturation restoration and subsequently,oil displacement due to the hysteresis effect.At this condition,CO2 would act as insitu dissolved gas into the oil phase,and play the role of an artificial solution gas drive(SGD).In this study,the effect of SGD as an extra oil recovery mechanism after secondary and tertiary CWI(SCWI-TCWI)modes has been experimentally investigated in carbonate rocks using coreflood tests.The depressurization tests resulted in more than 25%and 18%of original oil in place(OOIP)because of the SGD after SCWI and TCWI tests,respectively.From the ultimate enhanced oil recovery point of view,the efficiency of SGD was observed to be more than one-third of that of CWI itself.Furthermore,the pressure drop data revealed that the system pressure depends more on the oil production pattern than water production.
文摘Purpose:The objective of this scoping review was to summarize systematically the available literature investigating the relationships between the coronavirus disease 2019(COVID-19)pandemic and movement behaviors(physical activity,sedentary behavior,and sleep)of school-aged children(aged 511 years)and youth(aged 1217 years)in the first year of the COVID-19 outbreak.Methods:Searches for published literature were conducted across 6 databases on 2 separate search dates(November 25,2020,and January 27,2021).Results were screened and extracted by 2 reviewers(DCP and KR)independently,using Covidence.Basic numeric analysis and content analysis were undertaken to present thematically the findings of included studies according to the associated impact on each movement behavior.Results:A total of 1486 records were extracted from database searches;of those,150 met inclusion criteria and were included for analysis.Of 150 articles,110 were empirical studies examining physical activity(n=77),sedentary behavior/screen time(n=58),and sleep(n=55).Results consistently reported declines in physical-activity time,increases in screen time and total sedentary behavior,shifts to later bed and wake times,and increases in sleep duration.The reported impacts on movement behaviors were greater for youth than for children.Conclusion:The COVID-19 pandemic is related to changes in the quantity and nature of physical activity,sedentary behavior,and sleep among children and youth.There is an urgent need for policy makers,practitioners,and researchers to develop solutions for attenuating adverse changes in physical activity and screen time among children and youth.
文摘Imbibition of water,as wetting phase in oil-wet fractured carbonate reservoirs,plays a key role in fluid flow between matrix and fracture system.The type of injected seawater and its chemistry would profoundly influence the imbibition process.In this study,the impact of smart water(a brine that its ions have been adjusted to facilitate oil recovery)and low salinity water on co-and counter-current imbibition processes for oil-wet carbonate cores has been experimentally investigated.The results show an increase of about 10% in oil recovery for co-and counter-currents for smart seawater imbibition compared to that of low salinity seawater.In addition,as a result of the influence of co-and counter-current on each other,by co-current removal from one core face,the countercurrent in the other face would be intensified by as much as about 75%.A close examination of different lengths(5,7 and 9 cm)of carbonate cores with the same permeability revealed that by decreasing porous medium length,the amount of counter-current producing oil would be decreased so that in the 5 cm core,counter current oil production will not happen.For similar core lengths by increasing permeability,the share of counter current flow would be decreased approximately 18% since the capillary pressure could not overcome non-wetting phase viscous forces.Considering the role of matrix length along with a modified brine(which is designed according to the matrix mixture)strengthen the relevant mechanisms to have more oil production so that the higher thickness of matrix causes the higher amount of co-current oil producing and consequently more total recovery.
文摘Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration,interfacial tension(IFT)reduction,oil viscosity reduction,formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation.To the best of the authors’ knowledge,the synthesis of a new nanocomposite has been studied in this paper for the first time.It consists of nanoparticles of both SiO2 and Fe3O4.Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs.According to the previous studies,Fe3O4 has been used in the prevention or reduction of asphaltene precipitation and SiO2 has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery.According to the experimental results,the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually.According to the results obtained for the use of this nanocomposite,understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.
文摘The effect of upstream velocity pertuibations on the response of a premixed flame was investigated in terms of the flame transfer function dependency on excitation frequency.In this study,the assumption of constant flame speed was extended and the effect of flame speed development was considered;i.e.,the flame speed would grow with the time after ignition or with the distance from a flame-holder.In the present study,the kinematics of a conical flame was investigated by linearization of the front tracking equation of flame to uniform and convected fluctuations of the flow velocity and the response was compared with that of a V-shaped flame and the experimental data in the previous studies.The results show that the effect of flame speed development could influence a decreasing gain and increase the phase of the flame response to the uniform velocity oscillations in low and moderate frequencies.Comparing the variations in the gain of flame response upon normalized frequency,show that a conical flame has lower values than the V-flame.In other woods,these flames might be less susceptible to combustion instabilities than the V-flames.Furthennore,the variations in phase of the V-flames responses,which show a quasi-linear behavior with normalized frequency,have higher values than the saturated behavior in phase of the conical flame responses.Also,considering that the flame speed development induces an increase in the gain and phase of the conical flame response to the convected velocity oscillations in certain frequencies;because the developed flame front has longer length in comparison to the flame front in constant flame speed model.Therefore,the flame length may be longer than convective wavelength and the heat release would be generated in different points of the flame;consequently the flow oscillations might exert a stronger impact on the unsteady heat release fluctuations.
文摘Background: Drug abuse could cause complications;infection and overdose are the most prevalent of them. Unreliable history of addicted patients also makes the diagnosis difficult and leads to delayed treatment and poor prognosis. Early recognition and prompt treatment are required to minimize the destructive damage. To our knowledge, there is not any previous report of bilateral eye injection among drug abusers, causing traumatic endophthalmitis in the English literature and our report helps ophthalmologists to think about rare sources of endophthalmitis. Aim: The aim is to emphasize the importance of considering exogenous endophthalmitis in I.V. drug users who abuse drugs. Methods: A 40-year-old I.V. drug user man was referred complaining a history of the pain, redness and impaired vision of both eyes from three days ago. Perilimbal injection and anterior chamber cellular reaction were present in both eyes. Both corneas were hazy;corneal edema, abscess, sealed corneal lacerations and dull red reflex were visible in both eyes. Results: After an ultrasonography based on the suspicion of endophthalmitis, anterior chamber and vitreous aspiration and intravitreal injection of vancomycin 1 mg and ceftazidime 2.25 mg were performed. The right eye rapidly deteriorated and was eviscerated two days later and the left eye had a good response to medications. Conclusion: This report illustrates that the orbit can be a potential site of drug injection and endophthalmitis should be considered in individuals who abuse drugs.
基金the financial and scientific supports from EOR Research Centre of Shiraz University and the Reservoir Modelling and Simulation Centre(RMSC)。
文摘In this study,the impacts of solutal Marangoni phenomenon on multiphase flow in static and micromodel geometries have experimentally been studied and the interactions between oil droplet and two different alkaline solutions(i.e.MgS04 and Na_2 CO_3) were investigated.The static tests revealed that the Marangoni convection exists in the presence of the alkaline and oil which should carefully be considered in porous media.In the micromodel experiments,observations showed that in the MgS04 flooding,the fluids stayed almost stationary,while in the Na2 C03 flooding,a spontaneous movement was detected.The changes in the distribution of fluids showed that the circular movement of fluids due to the Marangoni effects can be effective in draining of the unswept regions.The dimensional analysis for possible mechanisms showed that the viscous,gravity and diffusion forces were negligible and the other mechanisms such as capillary and Marangoni effects should be considered in the investigated experiments.The value of the new defined Marangoni/capillary dimensionless number for the Na2 C03 solution was orders of magnitude larger than the MgS04 flooding scenario which explains the differences between the two cases and also between different micromodel regions.In conclusion,the Marangoni convection is activated by creating an ultra-low IFT condition in multiphase flow problems that can be profoundly effective in increasing the phase mixing and microscopic efficiency.
文摘In this paper,a new robust approach based on Least Square Support Vector Machine(LSSVM)as a proxy model is used for an automatic fractured reservoir history matching.The proxy model is made to model the history match objective function(mismatch values)based on the history data of the field.This model is then used to minimize the objective function through Particle Swarm Optimization(PSO)and Imperialist Competitive Algorithm(ICA).In automatic history matching,sensitive analysis is often performed on full simulation model.In this work,to get new range of the uncertain parameters(matching parameters)in which the objective function has a minimum value,sensitivity analysis is also performed on the proxy model.By applying the modified ranges to the optimization methods,optimization of the objective function will be faster and outputs of the optimization methods(matching parameters)are produced in less time and with high precision.This procedure leads to matching of history of the field in which a set of reservoir parameters is used.The final sets of parameters are then applied for the full simulation model to validate the technique.The obtained results show that the present procedure in this work is effective for history matching process due to its robust dependability and fast convergence speed.Due to high speed and need for small data sets,LSSVM is the best tool to build a proxy model.Also the comparison of PSO and ICA shows that PSO is less time-consuming and more effective.
文摘Nigella sativa L. (Black seed), is a traditional herbal medicine that has been used for many purposes. The present study was designed to investigate the effects of hydro-alcoholic extract of nigella sativa L. (NS) on performance of Forced Swimming Test (FST), blood biochemical parameters related to fatigue and thyroid functions. Therefore, Blood Urea Nitrogen (BUN), Creatine Kinase (CK), Lactic Dehydrogenase (LDH), and Total Protein (TP), triiodothyronine T3, thyroxin T4 and TSH tests were investigated. Thirty five male adult mice were randomly divided into five groups: three NS-fed groups, one fluoxetine treated group and one control group. Three NS experimental groups received hydro-alcoholic extract of NS at doses of 50, 100 and 200 mg/kg orally for two weeks. Immobility time decreased in all NS groups compared with control group. Administration of NS significantly increased the concentration of T3 and T4 of the treatment groups. On the contrary, the amount of BUN, CK, LDH, TP and TSH decreased. In conclusion, black seed extract at the experimented doses showed anti-depressant, anti-fatigue and hyperthyroid effects.
文摘In this article, we introduce the concept of entropy functional for continuous systems on compact metric spaces, and prove some of its properties. We also extract the Kolmogorov entropy from the entropy functional.
文摘By comparing numerical simulation results of single-porosity and dual-porosity models,the significant effect of reinfiltration to naturally fractured reservoirs was confirmed.A new governing equation was proposed for oil drainage in a matrix block under the reinfiltration process.Utilizing inspectional analysis,a dimensionless equation suitable for scaling of recovery curves for matrix blocks under reinfiltration has been obtained.By the design of experiments,test cases with different rock and fluid properties were defined to confirm the scope of the presented equation.The defined cases were simulated using a realistic numerical simulation approach.This method can estimate the oil amount getting into the matrix block through reinfiltration,help simulate the oil drainage process in naturally fractured reservoirs accurately,and predict the recovery rate of matrix block in the early to middle periods of production.Using the defined scaling equation in the dual-porosity model can improve the accuracy of the predicted recovery rate.
文摘Terpenoids are novel natural products isolated from mastic gum.Mastic gum was obtained from the Pistacia Lentiscus tree.Scientific investigations have documented medical and pharmacological properties of mastic gum such as memory enhancement,antifungal,and antibacterial activities.It was astonishing to study the possible interaction of mastic gum extract with microtubule proteins which are involved in memory and consciousness since the administration of mastic gum is evidenced in the improvement of brain functions.Since a number of studies have demonstrated the effect of microtubule dynamics on mammals'memory,in this study,we investigated the effect of Oxygenated Sesquiterpenes(OST)on microtubule polymerization in vitro.OST was purified from the ethanolic extract of mastic gum.The results revealed that OST induces microtubule polymerization;however,microtubule depolymerization was not affected and fluorometric assays showed conformational changes of tubulin in the presence of OST.We interestingly found that colchicine was unable to inhibit MT assembly in the presence of OST and OST was solely more efficient than the combination of OST with paclitaxel for elevating microtubule polymerization rate.We hope that OST could be a promising agent for memory enhancement and the treatment of neurodegenerative diseases as a novel tubulin-binding compound.
文摘Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery.Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tension reduction, impulsive emulsion formation and wettability alteration of porous media. The presence of dispersed nanoparticles in injected fluids would enhance the recovery process through their movement towards oil–water interface. This would cause the interfacial tension to be reduced. In this research, the effects of different types of nanoparticles and different nanoparticle concentrations on EOR processes were investigated. Different flooding experiments were investigated to reveal enhancing oil recovery mechanisms. The results showed that nanoparticles have the ability to reduce the IFT as well as contact angle, making the solid surface to more water wet. As nanoparticle concentration increases more trapped oil was produced mainly due to wettability alteration to water wet and IFT reduction. However, pore blockage was also observed due to adsorption of nanoparticles, a phenomenon which caused the injection pressure to increase. Nonetheless, such higher injection pressure could displace some trapped oil in the small pore channels out of the model. The investigated results gave a clear indication that the EOR potential of nanoparticle fluid is significant.
基金financial support from National Iranian South Oil Company(NISOC)
文摘Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To achieve appropriate ultimate oil recovery in these reservoirs,a water-based enhanced oil recovery method must be capable of altering the wettability of matrix blocks.Previous studies showed that carbonated water can alter wettability of carbonate oil-wet rocks toward less oil-wet or neutral wettability conditions,but the degree of modification is not high enough to allow water to imbibe spontaneously into the matrix blocks at an effective rate.In this study,we manipulated carbonated brine chemistry to enhance its wettability alteration features and hence to improve water imbibition rate and ultimate oil recovery upon spontaneous imbibition in dolomite rocks.First,the contact angle and interfacial tension(IFT)of brine/crude oil systems were measured for several synthetic brine samples with different compositions.Thereafter,two solutions with a significant difference in WAI(wettability alteration index)but approximately equal brine/oil IFT were chosen for spontaneous imbibition experiments.In the next step,spontaneous imbibition experiments at ambient and high pressures were conducted to evaluate the ability of carbonated smart water in enhancing the spontaneous imbibition rate and ultimate oil recovery in dolomite rocks.Experimental results showed that an appropriate adjustment of the imbibition brine(i.e.,carbonated smart water)chemistry improves imbibition rate of carbonated water in oil-wet dolomite rocks as well as the ultimate oil recovery.
文摘Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.
