Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing...Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing characteristics of tight basalts and the reactions between fractured basalt and SC-CO_(2).In this study,hydraulic fracturing experiments were conducted on cylindrical basalt specimens using water and SC-CO_(2) as fracturing fluids.Geometric parameters were proposed to characterize the fracture morphologies based on the three-dimensional(3D)reconstructions of fracture networks.The rock slices with induced fractures after SC-CO_(2) fracturing were then processed for fluid(deionized water/SC-CO_(2))-basalt reaction tests.The experimental results demonstrate that SC-CO_(2) fracturing can induce complex and tortuous fractures with spatially dispersed morphologies.Other fracturing behaviors accompanying the acoustic emission(AE)signals and pump pressure changes show that the AE activity responds almost simultaneously to variation in the pump pressure.The fractured basalt blocks exposed to both SC-CO_(2) and water exhibit rough and uneven surfaces,along with decreased intensities in the element peaks,indicating that solubility trapping predominantly occurs during the early injection stage.The above findings provide a laboratory research basis for understanding the fracturing and sequestration issues related to effective CO_(2) utilization.展开更多
The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic e...The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic ecosystems and human health. To solve this problem, this study synthesized a composite of titanium dioxide (TiO2) and steel slag nanocomposites (SSNC) at a 1:2 mass ratio to create a robust photocatalyst for the treatment of synthetic wastewater. The efficacy of this catalyst in degrading various dye pollutants, including methylene blue (MB), was tested under simulated solar light conditions. Comprehensive analyses were conducted to assess the physical and chemical characteristics, crystalline structure, energy gap, and point of zero charge of the composite. The TiO2-SSNC composite catalyst exhibited excellent stability, with a point of zero charge at 8.342 and an energy gap of 2.4 eV. The degradation process conformed to pseudo-first-order kinetics. Optimization of operational parameters was achieved through the response surface methodology. Reusability tests demonstrated that the TiO2-SSNC composite catalyst effectively degraded up to 93.41% of MB in the suspended mode and 92.03% in the coated mode after five cycles. Additionally, the degradation efficiencies for various dyes were significant, highlighting the potential of the composite for broad applications in industrial wastewater treatment. This study also explored the degradation mechanisms and identified byproducts, establishing a pathway for contaminant breakdown. The cost-benefit analysis revealed a total cost of 0.842 8 USD per cubic meter for each treatment activity, indicating low operational and production costs. These findings underscore the promise of the TiO2-SSNC composite as a cost-effective and efficient alternative for wastewater purification.展开更多
The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_...The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_(2),(Cr,Mn)3O_(4),and Cr2O_(3) from the inner to outer layers.A shallow carburization depth of approximately 130 nm indicates excellent resistance to carburization.The roles of key elements in 18/8 austenitic stainless steel represented by 304LN,such as Cr,Ni,and Si,were analyzed,highlighting their contributions to anti-carburization performance and corrosion resistance under harsh conditions.展开更多
Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method ...Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method for the reuse or recycling of catalysts.Herein,an N-heterocyclic carbene-pyridine molybdenum complex supported over SBA-15(Mo@SBA-15)was used as an efficient and recyclable catalyst for converting CO_(2) and epoxides into cyclic carbonates.Mo@SBA-15 in combination with tetra-butylammonium bromide(TBAB)shows high catalytic activity in the synthesis of cyclic carbonates under 100℃and 1 MPa CO_(2) pressure.In addition,Mo@SBA-15 was reused seven times without any significant activity loss.展开更多
Understanding the mechanical and transport behavior of thin(i.e.small aperture)cracks slipping under supercritical carbon dioxide(sc-CO_(2))conditions is essential to evaluate the integrity of sealing formations with ...Understanding the mechanical and transport behavior of thin(i.e.small aperture)cracks slipping under supercritical carbon dioxide(sc-CO_(2))conditions is essential to evaluate the integrity of sealing formations with buoyant sc-CO_(2)below and the success of waterless fracturing.The two major items of interest in this work are frictional strength and permeability change of the crack.We used a triaxial cell that permits in situ visualization to conduct and monitor slippage along the faces of narrow cracks subjected to triaxial stresses.Such cracks are analogs to small geological faults.We tested carbonate-rich,1-inch diameter Wolfcamp shale samples that are saw cut 30to vertical to create a thin crack.Friction coefficients ranged from about 0.6 to 0.8 consistent with expectations for brittle rocks.The sc-CO_(2)generally did not alter friction coefficient over the time scale of experiments.From a transport perspective,saturating cracks with sc-CO_(2)substantially decreased permeability of the crack by 26%e52%,while slip resulted in a variety of permeability responses.Overall,the combined impact of sc-CO_(2)saturation and slip reduced fault permeability for all tests.Our observations support the notion that the sealing capacity of some caprocks improves when saturated with sc-CO_(2)and that some slip of small fractures is not necessarily detrimental to caprock integrity.展开更多
Osteoarthritis(OA)of the knee is a common degenerative articular disorder and is one of the main causes of pain and functional disability.Cartilage damage is frequently linked to elevated osteoarthritis incidence.Supe...Osteoarthritis(OA)of the knee is a common degenerative articular disorder and is one of the main causes of pain and functional disability.Cartilage damage is frequently linked to elevated osteoarthritis incidence.Supercritical carbon dioxide(scCO_(2))decellularized cartilage graft produced from the porcine cartilage is an ideal candidate for cartilage tissue engineering.In the present study,we derived collagen type II(Col II)solution from the scCO_(2) decellularized porcine cartilage graft(dPCG)and compared its efficacy with hyaluronic acid(HA)in the surgical medial meniscectomy(MNX)induced post-traumatic osteoarthritis(PTOA)model.Dose-dependent attenuation of the OA(12.3±0.8)progression was observed in the intra-articular administration of Col II solution(7.3±1.2)which significantly decreased the MNX-induced OA symptoms similar to HA.The pain of the OA group(37.4±2.7)was attenuated dose-dependently by Col II solution(45.9±4.1)similar to HA(43.1±3.5)as evaluated by a capacitance meter.Micro-CT depicted a dose-dependent attenuation of articular cartilage damage by the Col II solution similar to HA treatment.A significant(p<0.001)dose-dependent elevation in the bone volume was also observed in Col II solution-treated OA animals.The protective competence of Col II solution on articular cartilage damage is due to its significant(p<0.001)increase in the expression of type II collagen,aggrecan and SOX-9 similar to HA.To conclude,intra-articular adminis-tration of type II collagen solution and HA reestablished the injured cartilage and decreased osteoarthritis progression in the experimental PTOA model.展开更多
Artificial CO_(2)removal from the atmosphere(also referred to as negative CO_(2)emissions)has been proposed as a potential means to counteract anthropogenic climate change.Here we use an Earth system model to examine ...Artificial CO_(2)removal from the atmosphere(also referred to as negative CO_(2)emissions)has been proposed as a potential means to counteract anthropogenic climate change.Here we use an Earth system model to examine the response of ocean acidification to idealized atmospheric CO_(2)removal scenarios.In our simulations,atmospheric CO_(2)is assumed to increase at a rate of 1%per year to four times its pre-industrial value and then decreases to the pre-industrial level at a rate of 0.5%,1%,2%per year,respectively.Our results show that the annual mean state of surface ocean carbonate chemistry fields including hydrogen ion concentration([H^(+)]),pH and aragonite saturation state respond quickly to removal of atmospheric CO_(2).However,the change of seasonal cycle in carbonate chemistry lags behind the decline in atmospheric CO_(2).When CO_(2)returns to the pre-industrial level,over some parts of the ocean,relative to the pre-industrial state,the seasonal amplitude of carbonate chemistry fields is substantially larger.Simulation results also show that changes in deep ocean carbonate chemistry substantially lag behind atmospheric CO_(2)change.When CO_(2)returns to its pre-industrial value,the whole-ocean acidity measured by[H^(+)]is 15%-18%larger than the pre-industrial level,depending on the rate of CO_(2)decrease.Our study demonstrates that even if atmospheric CO_(2)can be lowered in the future as a result of net negative CO_(2)emissions,the recovery of some aspects of ocean acidification would take decades to centuries,which would have important implications for the resilience of marine ecosystems.展开更多
The problem of water depollution is gaining importance, especially as regulatory standards concerning drinking water are increasingly strict. The different industries (textile industries) generate chemically stable po...The problem of water depollution is gaining importance, especially as regulatory standards concerning drinking water are increasingly strict. The different industries (textile industries) generate chemically stable pollutants such as methyl orange which make their degradation difficult. It is therefore necessary to find new, more effective techniques for the treatment of these discharges. Among the different solutions proposed to deal with this problem, we find advanced oxidation processes (POAs) which are clean and promising technologies in the field of wastewater depollution. In this regard, heterogeneous photocatalysis was used in an aqueous suspension of titanium oxide (TiO2) using a ultraviolet (UV) lamp as artificial radiation. The objective of this work is to study the influence of some operating parameters such as: the catalyst mass, the initial pollutant concentration, the volume of the solution and the pH of the solution, were examined. The results obtained showed that this photocatalyst made it possible to degrade 99.85% of the initial concentration of methyl orange (10 ppm), after 240 min of irradiation with an optimal mass of 0.50 g of TiO2 for a volume of 200 mL of methyl orange solution at pH = 3.0.展开更多
In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential inve...In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.展开更多
This study used a Polyindole in combination with TiO2 nanocatalyst as an efficient heterogeneous catalyst to carry out a multi-component Hantzsch reaction involving different aromatic aldehydes with methyl acetoacetat...This study used a Polyindole in combination with TiO2 nanocatalyst as an efficient heterogeneous catalyst to carry out a multi-component Hantzsch reaction involving different aromatic aldehydes with methyl acetoacetate, and aqueous ammonium to create 1,4-dihydropyridine derivatives under solvent free condition at ambient temperature. A broad range of aldehydes and methyl acetoacetates, ranging from heteroaromatic to polyaromatic one, with high level of functional group tolerance can be used to provide the desired products possessing relevant medicinal moiety in high yields. This technology has prospective advantages over current protocols, including the utilization of a cheap, stable, recyclable, and safe catalyst, quicker reaction times with higher yields and simple product isolation.展开更多
Flexible polymer-based dye-sensitized solar cells (DSSCs) offer promising potential for lightweight, cost-effective and versatile photovoltaic applications. However, the critical challenge in their widespread applicat...Flexible polymer-based dye-sensitized solar cells (DSSCs) offer promising potential for lightweight, cost-effective and versatile photovoltaic applications. However, the critical challenge in their widespread applications is the weak thermal stability of most polymeric substrates, which can only withstand a maximum temperature processing of 150˚C. In this study, a facile and low-cost strategy is proposed to develop at low temperature DSSC flexible photoanode based on a polymeric matrix. Highly porous nanocomposites fibrous mats composed of polyethylene terephthalate (PET) and titanium dioxide (TiO2) nanobars were prepared through an electrospinning process using different configurations (uniaxial electrospinning, coaxial electrospinning, and electrospray-assisted electrospinning). These techniques enabled precise control of the microstructure and the positioning of TiO2 within the composite nanofibers. Therefore, the as-produced photoanodes were loaded with N719 dye and tested in DSSC prototype using iodide-triiodide electrolyte and platinum (Pt) coated counter electrode. The results show that incorporating TiO2 on the fiber surface through the electrospray-assisted electrospinning enhanced the performance of the nanofiber composite, leading to improved dye loading capacity, electron transfer efficiency and photovoltaic performance.展开更多
基金supported by the National Key Research and Development Project(Grant No.2023YFE0110900)the National Natural Science Foundation of China(Grant No.42320104003)the Shanghai Pujiang Programme(Grant No.23PJD105).
文摘Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing characteristics of tight basalts and the reactions between fractured basalt and SC-CO_(2).In this study,hydraulic fracturing experiments were conducted on cylindrical basalt specimens using water and SC-CO_(2) as fracturing fluids.Geometric parameters were proposed to characterize the fracture morphologies based on the three-dimensional(3D)reconstructions of fracture networks.The rock slices with induced fractures after SC-CO_(2) fracturing were then processed for fluid(deionized water/SC-CO_(2))-basalt reaction tests.The experimental results demonstrate that SC-CO_(2) fracturing can induce complex and tortuous fractures with spatially dispersed morphologies.Other fracturing behaviors accompanying the acoustic emission(AE)signals and pump pressure changes show that the AE activity responds almost simultaneously to variation in the pump pressure.The fractured basalt blocks exposed to both SC-CO_(2) and water exhibit rough and uneven surfaces,along with decreased intensities in the element peaks,indicating that solubility trapping predominantly occurs during the early injection stage.The above findings provide a laboratory research basis for understanding the fracturing and sequestration issues related to effective CO_(2) utilization.
基金supported by the Department of Chemical and Petrochemical Engineering,Egypt-Japan University of Science and Technology.
文摘The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic ecosystems and human health. To solve this problem, this study synthesized a composite of titanium dioxide (TiO2) and steel slag nanocomposites (SSNC) at a 1:2 mass ratio to create a robust photocatalyst for the treatment of synthetic wastewater. The efficacy of this catalyst in degrading various dye pollutants, including methylene blue (MB), was tested under simulated solar light conditions. Comprehensive analyses were conducted to assess the physical and chemical characteristics, crystalline structure, energy gap, and point of zero charge of the composite. The TiO2-SSNC composite catalyst exhibited excellent stability, with a point of zero charge at 8.342 and an energy gap of 2.4 eV. The degradation process conformed to pseudo-first-order kinetics. Optimization of operational parameters was achieved through the response surface methodology. Reusability tests demonstrated that the TiO2-SSNC composite catalyst effectively degraded up to 93.41% of MB in the suspended mode and 92.03% in the coated mode after five cycles. Additionally, the degradation efficiencies for various dyes were significant, highlighting the potential of the composite for broad applications in industrial wastewater treatment. This study also explored the degradation mechanisms and identified byproducts, establishing a pathway for contaminant breakdown. The cost-benefit analysis revealed a total cost of 0.842 8 USD per cubic meter for each treatment activity, indicating low operational and production costs. These findings underscore the promise of the TiO2-SSNC composite as a cost-effective and efficient alternative for wastewater purification.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0410000)the CAS Project for Young Scientists in Basic Research(No.YSBR-043)+1 种基金the CNNC Science Fund for Talented Young Scholars,the National Funding Program for Postdoctoral Researchers(GZC20232747)the Youth Innovation Promotion Association CAS(2022187).
文摘The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_(2),(Cr,Mn)3O_(4),and Cr2O_(3) from the inner to outer layers.A shallow carburization depth of approximately 130 nm indicates excellent resistance to carburization.The roles of key elements in 18/8 austenitic stainless steel represented by 304LN,such as Cr,Ni,and Si,were analyzed,highlighting their contributions to anti-carburization performance and corrosion resistance under harsh conditions.
文摘Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method for the reuse or recycling of catalysts.Herein,an N-heterocyclic carbene-pyridine molybdenum complex supported over SBA-15(Mo@SBA-15)was used as an efficient and recyclable catalyst for converting CO_(2) and epoxides into cyclic carbonates.Mo@SBA-15 in combination with tetra-butylammonium bromide(TBAB)shows high catalytic activity in the synthesis of cyclic carbonates under 100℃and 1 MPa CO_(2) pressure.In addition,Mo@SBA-15 was reused seven times without any significant activity loss.
基金supported as part of the Center for Mechanistic Control of Unconventional Formations(CMC-UF),an Energy Frontier Research Center funded by the U.S.Department of Energy,Of-fice of Science under DOE(BES)Award DE-SC0019165Stanford Nano Shared Facilities(SNSF)with support from NSF under award CMMI-1532224SNSF is additionally supported by the NSF as part of the National Nanotechnology Coordinated Infrastructure under award ECCS-1542152.
文摘Understanding the mechanical and transport behavior of thin(i.e.small aperture)cracks slipping under supercritical carbon dioxide(sc-CO_(2))conditions is essential to evaluate the integrity of sealing formations with buoyant sc-CO_(2)below and the success of waterless fracturing.The two major items of interest in this work are frictional strength and permeability change of the crack.We used a triaxial cell that permits in situ visualization to conduct and monitor slippage along the faces of narrow cracks subjected to triaxial stresses.Such cracks are analogs to small geological faults.We tested carbonate-rich,1-inch diameter Wolfcamp shale samples that are saw cut 30to vertical to create a thin crack.Friction coefficients ranged from about 0.6 to 0.8 consistent with expectations for brittle rocks.The sc-CO_(2)generally did not alter friction coefficient over the time scale of experiments.From a transport perspective,saturating cracks with sc-CO_(2)substantially decreased permeability of the crack by 26%e52%,while slip resulted in a variety of permeability responses.Overall,the combined impact of sc-CO_(2)saturation and slip reduced fault permeability for all tests.Our observations support the notion that the sealing capacity of some caprocks improves when saturated with sc-CO_(2)and that some slip of small fractures is not necessarily detrimental to caprock integrity.
文摘Osteoarthritis(OA)of the knee is a common degenerative articular disorder and is one of the main causes of pain and functional disability.Cartilage damage is frequently linked to elevated osteoarthritis incidence.Supercritical carbon dioxide(scCO_(2))decellularized cartilage graft produced from the porcine cartilage is an ideal candidate for cartilage tissue engineering.In the present study,we derived collagen type II(Col II)solution from the scCO_(2) decellularized porcine cartilage graft(dPCG)and compared its efficacy with hyaluronic acid(HA)in the surgical medial meniscectomy(MNX)induced post-traumatic osteoarthritis(PTOA)model.Dose-dependent attenuation of the OA(12.3±0.8)progression was observed in the intra-articular administration of Col II solution(7.3±1.2)which significantly decreased the MNX-induced OA symptoms similar to HA.The pain of the OA group(37.4±2.7)was attenuated dose-dependently by Col II solution(45.9±4.1)similar to HA(43.1±3.5)as evaluated by a capacitance meter.Micro-CT depicted a dose-dependent attenuation of articular cartilage damage by the Col II solution similar to HA treatment.A significant(p<0.001)dose-dependent elevation in the bone volume was also observed in Col II solution-treated OA animals.The protective competence of Col II solution on articular cartilage damage is due to its significant(p<0.001)increase in the expression of type II collagen,aggrecan and SOX-9 similar to HA.To conclude,intra-articular adminis-tration of type II collagen solution and HA reestablished the injured cartilage and decreased osteoarthritis progression in the experimental PTOA model.
基金supported by the National Natural Science Foundation of China(Nos.41975103,42275179,22022611,and 42005027)the Zhejiang Provincial Natural Science Foundation of China(No.LQ20D050003)。
文摘Artificial CO_(2)removal from the atmosphere(also referred to as negative CO_(2)emissions)has been proposed as a potential means to counteract anthropogenic climate change.Here we use an Earth system model to examine the response of ocean acidification to idealized atmospheric CO_(2)removal scenarios.In our simulations,atmospheric CO_(2)is assumed to increase at a rate of 1%per year to four times its pre-industrial value and then decreases to the pre-industrial level at a rate of 0.5%,1%,2%per year,respectively.Our results show that the annual mean state of surface ocean carbonate chemistry fields including hydrogen ion concentration([H^(+)]),pH and aragonite saturation state respond quickly to removal of atmospheric CO_(2).However,the change of seasonal cycle in carbonate chemistry lags behind the decline in atmospheric CO_(2).When CO_(2)returns to the pre-industrial level,over some parts of the ocean,relative to the pre-industrial state,the seasonal amplitude of carbonate chemistry fields is substantially larger.Simulation results also show that changes in deep ocean carbonate chemistry substantially lag behind atmospheric CO_(2)change.When CO_(2)returns to its pre-industrial value,the whole-ocean acidity measured by[H^(+)]is 15%-18%larger than the pre-industrial level,depending on the rate of CO_(2)decrease.Our study demonstrates that even if atmospheric CO_(2)can be lowered in the future as a result of net negative CO_(2)emissions,the recovery of some aspects of ocean acidification would take decades to centuries,which would have important implications for the resilience of marine ecosystems.
文摘The problem of water depollution is gaining importance, especially as regulatory standards concerning drinking water are increasingly strict. The different industries (textile industries) generate chemically stable pollutants such as methyl orange which make their degradation difficult. It is therefore necessary to find new, more effective techniques for the treatment of these discharges. Among the different solutions proposed to deal with this problem, we find advanced oxidation processes (POAs) which are clean and promising technologies in the field of wastewater depollution. In this regard, heterogeneous photocatalysis was used in an aqueous suspension of titanium oxide (TiO2) using a ultraviolet (UV) lamp as artificial radiation. The objective of this work is to study the influence of some operating parameters such as: the catalyst mass, the initial pollutant concentration, the volume of the solution and the pH of the solution, were examined. The results obtained showed that this photocatalyst made it possible to degrade 99.85% of the initial concentration of methyl orange (10 ppm), after 240 min of irradiation with an optimal mass of 0.50 g of TiO2 for a volume of 200 mL of methyl orange solution at pH = 3.0.
文摘In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.
文摘This study used a Polyindole in combination with TiO2 nanocatalyst as an efficient heterogeneous catalyst to carry out a multi-component Hantzsch reaction involving different aromatic aldehydes with methyl acetoacetate, and aqueous ammonium to create 1,4-dihydropyridine derivatives under solvent free condition at ambient temperature. A broad range of aldehydes and methyl acetoacetates, ranging from heteroaromatic to polyaromatic one, with high level of functional group tolerance can be used to provide the desired products possessing relevant medicinal moiety in high yields. This technology has prospective advantages over current protocols, including the utilization of a cheap, stable, recyclable, and safe catalyst, quicker reaction times with higher yields and simple product isolation.
文摘Flexible polymer-based dye-sensitized solar cells (DSSCs) offer promising potential for lightweight, cost-effective and versatile photovoltaic applications. However, the critical challenge in their widespread applications is the weak thermal stability of most polymeric substrates, which can only withstand a maximum temperature processing of 150˚C. In this study, a facile and low-cost strategy is proposed to develop at low temperature DSSC flexible photoanode based on a polymeric matrix. Highly porous nanocomposites fibrous mats composed of polyethylene terephthalate (PET) and titanium dioxide (TiO2) nanobars were prepared through an electrospinning process using different configurations (uniaxial electrospinning, coaxial electrospinning, and electrospray-assisted electrospinning). These techniques enabled precise control of the microstructure and the positioning of TiO2 within the composite nanofibers. Therefore, the as-produced photoanodes were loaded with N719 dye and tested in DSSC prototype using iodide-triiodide electrolyte and platinum (Pt) coated counter electrode. The results show that incorporating TiO2 on the fiber surface through the electrospray-assisted electrospinning enhanced the performance of the nanofiber composite, leading to improved dye loading capacity, electron transfer efficiency and photovoltaic performance.
