As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte com...As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte composition will influence energy density, operating temperature range and the practical applications of the VRFB. Various approaches to increase the energy density and operating temperature range have been proposed. The presence of electrolyte impurities, or the addition of a small amount of other chemical species into the vanadium solution can alter the stability of the electrolyte and influence cell perfor- mance, operating temperature range, energy density, electrochemical kinetics and cost effectiveness. This review provides a detailed overview of research on electrolyte additives including stabilizing agents, im- mobilizing agents, kinetic enhancers, as well as electrolyte impurities and chemical reductants that can be used for different purposes in the VRFBs.展开更多
One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which...One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir.So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study,the influence of three commercial inhibitors,namely;Cetyl Terimethyl Ammonium Bromide(CTAB),Sodium Dodecyl Sulfate(SDS),Triton X-100 and four non-commercial(Benzene,Benzoic Acid,Salicylic Acid,Naphthalene)inhibitors on two Iranian crude oils were investigated.This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor.Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene(structure and amount of impurities presented)has a significant impact on the selection of inhibitors.asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions.The results revealed distinguished mechanisms for asphaltene solubilization/dispersion(such as hydrogen bonding,pep interaction and acid-base interaction)and influence of additional side group(OH)on inhibition power of inhibitor.During the experiments,it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization.So,finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important.The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils.One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibi展开更多
The formation of mineral scale is a complex problem during the oilfield operations. Scale inhibitors are widely used to prevent salt precipitation within reservoirs, in downhole equipment, and in production facilities...The formation of mineral scale is a complex problem during the oilfield operations. Scale inhibitors are widely used to prevent salt precipitation within reservoirs, in downhole equipment, and in production facilities. The scale inhibitors not only must have high effectiveness to prevent scale formation, but also have good adsorption- desorption characteristics, which determine the operation duration of the scale inhibitors. This work is focused on the development of a new scale inhibitor for preventing cal- cium carbonate formation in three different synthetic for- mation waters. Scale inhibition efficiency, optical density of the solution, induction time of calcium carbonate for- mation, corrosion activity, and adsorption-desorption ability were investigated for the developed scale inhibitor. The optimum concentration of hydrochloric acid in the inhibitor was determined by surface tension measurement on the boundary layer between oil and the aqueous scale inhibitor solution. The results show that the optimum mass percentage of 5 % hydrochloric acid solution in the inhi- bitor was in the range of 8 % to 10 %. The new scale inhibitor had high efficiency at a concentration of 30 mg/L. The results indicate that the induction period for calcium carbonate nucleation in the presence of the new inhibitor was about 3.5 times longer than the value in the absence of the inhibitors. During the desorption process at reservoir conditions, the number of pore volumes injected into the carbonate core for the developed inhibitor was significantly greater than the volume of a tested industrial inhibitor, showing better adsorption/desorption capacity.展开更多
The therapeutic potential of saquinavir, a specific inhibitor of human immunodeficiency virus(HIV)-1 and HIV-2 protease enzymes, has been largely limited because of a low solubility and consequnt low bioavailability. ...The therapeutic potential of saquinavir, a specific inhibitor of human immunodeficiency virus(HIV)-1 and HIV-2 protease enzymes, has been largely limited because of a low solubility and consequnt low bioavailability. Thus, we aimed to design a supersaturated selfmicroemulsifying drug delivery system(S-SMEDDS) that can maintain a high concentration of saquinavir in gastro-intestinal fluid thorugh inhibiting the drug precipitation to enhance the lymphatic transport of saquinavir and to increase the bioavailability of saquinavir considerably. Solubilizing capacity of different oils, surfactants, and cosurfactants for saquinavir was evaluated to select optimal ingredients for preparation of SMEDDS.Through the construction of pseudo-ternary phase diagram, SMEDDS formulations were established. A polymer as a precipitation inhibitor was selected based on its viscosity and drug precipitation inhibiting capacity. The S-SMEDDS and SMEDDS designed were administered at an equal dose to rats. At predetermined time points, levels of saquinavir in lymph collected from the rats were assessed. SMEDDS prepared presented a proper selfmicroemulsification efficiency and dispersion stability. The S-SMEDDS fabricated using the SMEDDS and hydroxypropyl methyl cellulose 2910 as a precipitation inhibitor exhibited a signficantly enhanced solubilizing capacity for saquinavir. The drug concentration in a simulated intestinal fluid evaluated with the S-SMEDDS was also maintained at higher levels for prolonged time than that examined with the SMEDDS. The S-SMEDDS showed a considerably enhanced lymphatic absoprtion of saquinavir in rats compared to the SMEDDS.Therefore, the S-SMEDDS would be usefully exploited to enhance the lymphatic absorption of hydrophobic drugs that need to be targeted to the lymphatic system.展开更多
Manganese sulfide is often referred to as one of important inhibitors in grain-oriented electrical steels, which is of great importance to yield strong Goss texture. However, the early stage of nucleation for such inh...Manganese sulfide is often referred to as one of important inhibitors in grain-oriented electrical steels, which is of great importance to yield strong Goss texture. However, the early stage of nucleation for such inhibitors and their evolution during the processing has not been well understood. In present work we selected a Fe-3.12wt.%Si- 0.11wt.%Mn-0.021wt.%S model system and used FE-SEM and atom probe tomography （APT） to investigate the precipitation behavior of MnS inhibitors at near atomic scale. It was found that the Si-S enriched clusters with sizes of 5-15 nm were formed close to the MnS particles. The density of inhibitors decreased after large pseudo-plane-strain compression because of the effect of dislocation motion, and then slightly increased again when sample was aged at 200℃ for 48 h. The dislocations and grain boundaries can act as fast diffusion paths and assist the reemergence of Si-S enriched clusters.展开更多
文摘As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte composition will influence energy density, operating temperature range and the practical applications of the VRFB. Various approaches to increase the energy density and operating temperature range have been proposed. The presence of electrolyte impurities, or the addition of a small amount of other chemical species into the vanadium solution can alter the stability of the electrolyte and influence cell perfor- mance, operating temperature range, energy density, electrochemical kinetics and cost effectiveness. This review provides a detailed overview of research on electrolyte additives including stabilizing agents, im- mobilizing agents, kinetic enhancers, as well as electrolyte impurities and chemical reductants that can be used for different purposes in the VRFBs.
基金The authors would like to thank the Research Department of Ahwaz Petroleum University and National Iranian South Oil Company(NISOC)for supporting this study。
文摘One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing,surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir.So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study,the influence of three commercial inhibitors,namely;Cetyl Terimethyl Ammonium Bromide(CTAB),Sodium Dodecyl Sulfate(SDS),Triton X-100 and four non-commercial(Benzene,Benzoic Acid,Salicylic Acid,Naphthalene)inhibitors on two Iranian crude oils were investigated.This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor.Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene(structure and amount of impurities presented)has a significant impact on the selection of inhibitors.asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions.The results revealed distinguished mechanisms for asphaltene solubilization/dispersion(such as hydrogen bonding,pep interaction and acid-base interaction)and influence of additional side group(OH)on inhibition power of inhibitor.During the experiments,it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization.So,finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important.The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils.One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibi
文摘The formation of mineral scale is a complex problem during the oilfield operations. Scale inhibitors are widely used to prevent salt precipitation within reservoirs, in downhole equipment, and in production facilities. The scale inhibitors not only must have high effectiveness to prevent scale formation, but also have good adsorption- desorption characteristics, which determine the operation duration of the scale inhibitors. This work is focused on the development of a new scale inhibitor for preventing cal- cium carbonate formation in three different synthetic for- mation waters. Scale inhibition efficiency, optical density of the solution, induction time of calcium carbonate for- mation, corrosion activity, and adsorption-desorption ability were investigated for the developed scale inhibitor. The optimum concentration of hydrochloric acid in the inhibitor was determined by surface tension measurement on the boundary layer between oil and the aqueous scale inhibitor solution. The results show that the optimum mass percentage of 5 % hydrochloric acid solution in the inhi- bitor was in the range of 8 % to 10 %. The new scale inhibitor had high efficiency at a concentration of 30 mg/L. The results indicate that the induction period for calcium carbonate nucleation in the presence of the new inhibitor was about 3.5 times longer than the value in the absence of the inhibitors. During the desorption process at reservoir conditions, the number of pore volumes injected into the carbonate core for the developed inhibitor was significantly greater than the volume of a tested industrial inhibitor, showing better adsorption/desorption capacity.
文摘目的研究3种沉淀抑制剂(PPI)羟丙基甲基纤维素K4M(Hydroxypropyl methyl cellulose K4M,HPMC K4M)、醋酸羟丙甲纤维素琥珀酸酯MG(Hypromellose Acetate Succinate MG,HPMC AS MG)、聚乙烯己内酰胺-聚醋酸乙烯酯-聚乙二醇接枝共聚物(Polyvinylpyrrolidone,Soluplus)对临床口服剂量下pH值诱导延胡索乙素(dl-THP)过饱和相行为的影响。方法绘制dl-THP的pH值-溶解度相图和p H值转换过程中的去过饱和曲线,用溶解度相图佐证dl-THP相行为,以质量浓度-时间曲线下面积和过饱和度为指标分析沉淀抑制剂对dl-THP相行为的影响;采用偏振光显微镜、差示扫描量热法分析沉淀性质。结果临床给药剂量下,dl-THP在pH值转换过程中最大过饱和度为3.93,随时间推移失去过饱和;HPMC K4M、HPMC AS MG、Soluplus在pH值转换180 min内均能维持过饱和度。HPMC K4M、HPMC AS MG、Soluplus在浓度5%时维持过饱和度分别为1.19、1.89、1.36,浓度20%时为1.30、2.35、1.86、浓度50%时为1.30、2.60、2.07。偏振光显微镜和差示扫描量热法结果表明产生结晶沉淀。结论沉淀抑制剂均能改善pH值诱导延胡索乙素过饱和相行为,且这种改善行为随沉淀抑制剂种类和浓度的不同而不同,HPMC AS MG作用效果最佳。
基金the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(no.2015R1A5A1008958)supported by the Industry Technology Development Program(10077593)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)。
文摘The therapeutic potential of saquinavir, a specific inhibitor of human immunodeficiency virus(HIV)-1 and HIV-2 protease enzymes, has been largely limited because of a low solubility and consequnt low bioavailability. Thus, we aimed to design a supersaturated selfmicroemulsifying drug delivery system(S-SMEDDS) that can maintain a high concentration of saquinavir in gastro-intestinal fluid thorugh inhibiting the drug precipitation to enhance the lymphatic transport of saquinavir and to increase the bioavailability of saquinavir considerably. Solubilizing capacity of different oils, surfactants, and cosurfactants for saquinavir was evaluated to select optimal ingredients for preparation of SMEDDS.Through the construction of pseudo-ternary phase diagram, SMEDDS formulations were established. A polymer as a precipitation inhibitor was selected based on its viscosity and drug precipitation inhibiting capacity. The S-SMEDDS and SMEDDS designed were administered at an equal dose to rats. At predetermined time points, levels of saquinavir in lymph collected from the rats were assessed. SMEDDS prepared presented a proper selfmicroemulsification efficiency and dispersion stability. The S-SMEDDS fabricated using the SMEDDS and hydroxypropyl methyl cellulose 2910 as a precipitation inhibitor exhibited a signficantly enhanced solubilizing capacity for saquinavir. The drug concentration in a simulated intestinal fluid evaluated with the S-SMEDDS was also maintained at higher levels for prolonged time than that examined with the SMEDDS. The S-SMEDDS showed a considerably enhanced lymphatic absoprtion of saquinavir in rats compared to the SMEDDS.Therefore, the S-SMEDDS would be usefully exploited to enhance the lymphatic absorption of hydrophobic drugs that need to be targeted to the lymphatic system.
基金Acknowledgements The authors gratefully appreciate the financial support from the National Natural Science Foundation of China （Grant No. 51171019） and China＇s State Grid Corporation of Science and Technology Projects （SGRI-WD-71-13-002）.
文摘Manganese sulfide is often referred to as one of important inhibitors in grain-oriented electrical steels, which is of great importance to yield strong Goss texture. However, the early stage of nucleation for such inhibitors and their evolution during the processing has not been well understood. In present work we selected a Fe-3.12wt.%Si- 0.11wt.%Mn-0.021wt.%S model system and used FE-SEM and atom probe tomography （APT） to investigate the precipitation behavior of MnS inhibitors at near atomic scale. It was found that the Si-S enriched clusters with sizes of 5-15 nm were formed close to the MnS particles. The density of inhibitors decreased after large pseudo-plane-strain compression because of the effect of dislocation motion, and then slightly increased again when sample was aged at 200℃ for 48 h. The dislocations and grain boundaries can act as fast diffusion paths and assist the reemergence of Si-S enriched clusters.
