Rechargeable zinc-air batteries(ZABs)are a promising energy conversion device,which rely critically on electrocatalysts to accelerate their rate-determining reactions such as oxygen reduction(ORR)and oxygen evolution ...Rechargeable zinc-air batteries(ZABs)are a promising energy conversion device,which rely critically on electrocatalysts to accelerate their rate-determining reactions such as oxygen reduction(ORR)and oxygen evolution reactions(OER).Herein,we fabricate a range of bifunctional M-N-C(metal-nitrogen-carbon)catalysts containing M-Nx coordination sites and M/MxC nanoparticles(M=Co,Fe,and Cu)using a new class ofγ-cyclodextrin(CD)based metal-organic framework as the precursor.With the two types of active sites interacting with each other in the catalysts,the obtained Fe@C-FeNC and Co@C-CoNC display superior alkaline ORR activity in terms of low half-wave(E1/2)potential(~0.917 and 0.906 V,respectively),which are higher than Cu@C-CuNC(~0.829 V)and the commercial Pt/C(~0.861 V).As a bifunctional electrocatalyst,the Co@C-CoNC exhibits the best performance,showing a bifunctional ORR/OER overpotential(ΔE)of~0.732 V,which is much lower than that of Fe@C-FeNC(~0.831 V)and Cu@C-CuNC(~1.411 V),as well as most of the robust bifunctional electrocatalysts reported to date.Synchrotron X-ray absorption spectroscopy and density functional theory simulations reveal that the strong electronic correlation between metallic Co nanoparticles and the atomic Co-N4 sites in the Co@C-CoNC catalyst can increase the d-electron density near the Fermi level and thus effectively optimize the adsorption/desorption of intermediates in ORR/OER,resulting in an enhanced bifunctional electrocatalytic performance.The Co@C-CoNC-based rechargeable ZAB exhibited a maximum power density of 162.80 mW cm^(−2) at 270.30 mA cm^(−2),higher than the combination of commercial Pt/C+RuO2(~158.90 mW cm^(−2) at 265.80 mA cm^(−2))catalysts.During the galvanostatic discharge at 10 mA cm^(−2),the ZAB delivered an almost stable discharge voltage of 1.2 V for~140 h,signifying the virtue of excellent bifunctional ORR/OER electrocatalytic activity.展开更多
The embodied energy/CO2 of buildings in China and Japan, which reflects the characteristic industrial efficiency ofbui｜ding materials, is described in this paper. The energy consumption and CO2 intensities for the do...The embodied energy/CO2 of buildings in China and Japan, which reflects the characteristic industrial efficiency ofbui｜ding materials, is described in this paper. The energy consumption and CO2 intensities for the dominant materials used in buildings are derived from the energy consumption in factories, and the energy consumption to produce equipment is derived from IO （input/output） analysis in order to compare the embodied energy/CO2 for buildings between China and Japan based on the same estimation method. Although the energy consumption of structures in China is two to three times greater than in Japan, the interior finish and air conditioning equipment, for example, are simpler and smaller. As a result, the embodied energy/CO2 of office buildings in China is only 10% to 20% greater than that of Japanese office buildings. Thus, the embodied energy/CO2 of buildings depends on both industrial efficiencies and building design trends of the country.展开更多
In this study, we looked at a method quantifying EEC （embodied energy and CO2） and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the co...In this study, we looked at a method quantifying EEC （embodied energy and CO2） and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the covering thickness of concrete for reinforcing bars and the earthquake-resistant strength are methods to increase the durability of the structure. The calculation method to obtain the quantity of concrete and reinforcing bars is provided. The EEC increase is evaluated from the 2005 input-output table in Japan. These results show that EE （embodied energy） in the construction phase is increased by 11% to 20% and EC （embodied CO2） 17% to 32%. However, annual EE is reduced 66% to 72% and EC 70% to 79%,展开更多
CoCrMoW alloys with different nitrogen(N)additions(0,0.05,0.1,and 0.2 wt%)were prepared via laser powder bed fusion(LPBF).The effects of N content on the microstructure and mechanical properties were investigated.The ...CoCrMoW alloys with different nitrogen(N)additions(0,0.05,0.1,and 0.2 wt%)were prepared via laser powder bed fusion(LPBF).The effects of N content on the microstructure and mechanical properties were investigated.The results indicate that the LPBFed CoCrMoW alloy with 0.1 wt%N addition(0.1 N alloy)shows the best combination of mechanical properties with a yield strength of~983 MPa and an elongation of~19%.Both the LPBF process and the N addition impose great effects on suppressing theγtoεmartensitic transformation,resulting in a decrease in the width and amount ofεlaths/stacking faults.Besides,the N addition promotes the segregation of elements Mo,W,and Si along the cellular sub-grain boundaries(CBs),forming fine and discontinuous precipitates rich in Mo,W and Si along the CBs in the 0.1 N alloy,but dense and continuous(Mo,W)5Si_(3)precipitates along the CBs in the 0.2 N alloy.The(Mo,W)5Si_(3)precipitates with a tetragonal structure were observed and characterized for the first time in the Co-Cr based alloys.The negative mixing enthalpy between the non-metallic elements N,Si and the metallic elements Mo,W,Cr,and the rapid solidification induced segregation of high melting point elements such as Mo and W along CBs during LPBF process,synergistically contribute to the chemical heterogeneity in the alloys.The pure FCC matrix,the slightly increased segregation of Mo,W,Si elements and fine precipitates along the CBs contribute to the good combination of strength and elongation of the 0.1 N alloy.However,though pure FCC phase was present in the 0.2 N alloy,the dense and continuous(Mo,W)5Si_(3)precipitates along CBs acted as nucleation sites for cracks,deteriorating the elongation of the alloy.Overall,it is possible to tune the mechanical properties of the LPBFed CoCrMoW alloy by adjusting the local chemical heterogeneity.展开更多
Structural Health Monitoring(SHM)is the process of collecting,interpreting and analysing data from structures in order to determine its health status and the remaining life span.Composite materials have been extensive...Structural Health Monitoring(SHM)is the process of collecting,interpreting and analysing data from structures in order to determine its health status and the remaining life span.Composite materials have been extensively use in recent years in several industries with the aim at reducing the total weight of structures while improving their mechanical properties.However,composite materials are prone to develop damage when subjected to low to medium impacts(i.e.1-10 m/s and 11-30 m/s respectively).Hence,the need to use SHM techniques to detect damage at the incipient initiation in composite materials is of high importance.Despite the availability of several SHM methods for the damage identification in composite structures,no single technique has proven suitable for all circumstances.It must be noted that the amount of techniques available nowadays is too extensive to be comprehensively reviewed in a single paper.Therefore,the focus will be on techniques that can serve as a starting point for studies focusing on damage detection,localisation,assessment and prognosis on certain kinds of structures.Thus,the line of thought behind the search and the structure of this review is a result of objectives beyond the scope of the paper itself.Nevertheless,it was considered that,once the above was understood,an updated synopsis such as this could also be useful for other researchers in the same field.展开更多
This study presents a development on a time efficient approach to measure the Acoustic Impedance of Industrial Insulating materials using an impedance tube with single moveable microphone and a white noise generator. ...This study presents a development on a time efficient approach to measure the Acoustic Impedance of Industrial Insulating materials using an impedance tube with single moveable microphone and a white noise generator. The standing wave method is used to measure the acoustic properties (absorption coefficient and acoustic impedance) of sound absorbing materials. In order to use a burst of white noise instead of individual stationary sine waves, a signal processing technique was developed. The algorithm is based on the equation of simple harmonic motion, but uses distance as a variable, instead of time. This innovative method allows measuring at frequency resolutions as low as 5 Hz in a reasonably short amount of time. This is an advantage, as the classical standing wave method uses frequency resolutions of one-third of octaves for measurements, as otherwise time would be prohibitive. Experimental results are validated with those measured with the sine wave generator using one-third of octave frequencies by comparing their behaviours.展开更多
The objective of this research is to quantify the EEC （embodied energy/CO2） of a building. The EEC represents the energy consumption and CO2 emissions at individual phases of a building＇s life-cycle, such as constr...The objective of this research is to quantify the EEC （embodied energy/CO2） of a building. The EEC represents the energy consumption and CO2 emissions at individual phases of a building＇s life-cycle, such as construction （including manufacture of materials and equipment）, renewal （including repair work） and demolition. Energy and CO2 emission intensities in terms of 401 sectors were calculated, using the 2005 I-O （input-output） table in Japan. According to our case study conducted from the construction phase to demolition, the EC （embodied CO2） of an office building used for 60 years is 12,044 t-CO2 and 1,093 kg-CO2/m^2 in total. CO2 equivalent emissions （CO2e） by Freon gases, contained in building materials, equipment and devices, were also calculated. As the results, CO2e by insulators was 2% of the building＇s EC and CO2e by refrigerants was 9%-12% of the building＇s EC. It is important to keep reducing emissions of Freon gases contained in refrigerators.展开更多
In July 2009, the 2005 basic Japanese input/output table was publicized together with its physical transaction table. This research paper analyzed the 2005 IO （input/output） table to create building industry-related...In July 2009, the 2005 basic Japanese input/output table was publicized together with its physical transaction table. This research paper analyzed the 2005 IO （input/output） table to create building industry-related intensities and, at the same time, compared the building industry with industries at large for distribution margins and transportation. The analysis of distribution margins separately for middle and purchaser margins found that middle margins in the building industry are minor at 35% of the averages for all industries, while purchaser margins are sizable at 1.8 times, proving that it is an industry for which local production for local consumption is quite effective. CO2 emissions resulting from transportation in the building industry were calculated and concisely characterized. Although the ratio of transportation CO2 emissions to total CO2 emissions in each industry finds almost no difference between general industries and the building industry, transportation CO2 emissions per production value are two to three times heavier than those from general industries to be justified as a transportation-intensive industry.展开更多
Self-healing(SH)polymeric composites hold the promise of revolutionizing material performance and durability,but the challenge lies in achieving a delicate balance between healing efficiency and mechanical strength.He...Self-healing(SH)polymeric composites hold the promise of revolutionizing material performance and durability,but the challenge lies in achieving a delicate balance between healing efficiency and mechanical strength.Healing processes typically require dynamic,reversible bonds,which can weaken overall material strength,whereas robust materials rely on strong covalent bonds that resist healing.2D materials offer a solution by acting as nanofillers that not only improve mechanical properties but also introduce multifunctional benefits like electrical and thermal conductivity,responsiveness to stimuli,and enhanced barrier properties.Depending on their surface chemistry,thesematerials can either actively participate in the healing process or passively reinforce the polymer matrix.This review examines recent advancements in SH polymer composites enhanced with 2D fillers,exploring how factors like filler type,surface interactions,and loading levels impact both healing efficiency and mechanical strength.It compares the contributions of various 2D materials,identifying similarities and critical differences in their roles within polymermatrices.The article also highlights the need for standardized testing and advanced characterization techniques to better understand interfacial properties and healing mechanisms.By addressing current knowledge gaps and proposing future research directions,this review provides a comprehensive resource for advancing SH polymer systems,particularly in the integration of 2D materials for applications ranging from aerospace to electronics.展开更多
The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped c...The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped carbon layer(FCO@NC)was prepared using Fe-Co-based Prussian blue analogs(PBA)as a precursor.During the synthesis,dopamine was the carbon and nitrogen source.The reducing atmosphere was assured via NH_3/Ar,which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity.When used as anode materials for LIBs,the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g^(-1)at 0.3 A·g^(-1)after200 cycles with a capacity retention rate of 80.4%and426.76 mAh·g^(-1)after 500 cycles at a high current density of 1 A·g^(-1).It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability,and the heat treatment in NH_(3)/Ar atmosphere contributes to the oxygen vacancy content of the electrode materials,further facilitating its conductivity and electrochemical performance.展开更多
The ionic liquid(IL) tributylmethylammonium bis(trifluoromethylsulfonyl)amide([N4441][NTf2]) was used as neat lubricant and as an additive(1.5 wt%) in a polar oil to study its friction and wear reducing properties.Tri...The ionic liquid(IL) tributylmethylammonium bis(trifluoromethylsulfonyl)amide([N4441][NTf2]) was used as neat lubricant and as an additive(1.5 wt%) in a polar oil to study its friction and wear reducing properties.Tribological tests were completed for 90 minutes at room temperature and 100 °C in a reciprocating configuration at loads of 30 and 70 N,10 Hz-frequency,and 4 mm stroke length.Wear volume was measured by confocal microscopy and the surface-IL interaction determined by XPS.The main findings were that neat IL showed the best tribological behavior;the IL-containing mixture behaved similar to the base oil regarding friction,however outperformed the antiwear behavior of the base oil under higher temperature;surface-IL chemical interaction was found mainly at 100 °C.展开更多
Industrial process plants use emergency shutdown valves(ESDVs)as safety barriers to protect against hazardous events,bringing the plant to a safe state when potential danger is detected.These ESDVs are used extensivel...Industrial process plants use emergency shutdown valves(ESDVs)as safety barriers to protect against hazardous events,bringing the plant to a safe state when potential danger is detected.These ESDVs are used extensively in offshore oil and gas processing plants and have been mandated in the design of such systems from national and international standards and legislation.This paper has used actual ESDV operating data from four mid/late life oil and gas production platforms in the North Sea to research operational relationships that are of interest to those responsible for the technical management and operation of ESDVs.The first of the two relationships is between the closure time(CT)of the ESDV and the time it remains in the open position,prior to the close command.It has been hypothesised that the CT of the ESDV is affected by the length of time that it has been open prior to being closed(Time since the last stroke).In addition to the general analysis of the data series,two sub-categories were created to further investigate this possible relationship for CT and these are“above mean”and“below mean”.The correlations(Pearson's based)resulting from this analysis are in the“weak”and“very weak”categories.The second relationship investigated was the effect of very frequent closures to assess if this improves the CT.ESDV operational records for six subjects were analysed to find closures that occurred within a 24 h period of each other.However,no discriminating trend was apparent where CT was impacted positively or negatively by the frequent closure group.It was concluded that the variance of ESDV closure time cannot be influenced by the technical management of the ESDV in terms of scheduling the operation of the ESDV.展开更多
Synthesis of ultrathin heterostructures has received much attention in the recent past due to their unique physical and chemical properties.In this work,we report the synthesis of Fe_(2)TiO_(5)–TiO_(2)heterostructure...Synthesis of ultrathin heterostructures has received much attention in the recent past due to their unique physical and chemical properties.In this work,we report the synthesis of Fe_(2)TiO_(5)–TiO_(2)heterostructures using a simple hydrothermal technique employing natural ilmenite as the source.Hierarchically arranged nanostructures with interconnected nano-petals of thickness around 50 nm are obtained.The electrocatalytic properties of the synthesized Fe_(2)TiO_(5)–TiO_(2)heterostructures are enhanced following the cathodization technique.The observed enhancement in the synthesized materials’electrocatalytic property can be attributed to the defect-rich Fe_(2-x)TiO_(5-x)-TiO_(2-x)heterostructures.The current approach and technique discussed in this work offer a simple method to synthesize a nanostructured heterostructure material and create defects for enhancing electrocatalytic activity.展开更多
基金supported by the Shenzhen Government’s Plan of Science and Technology(JCYJ20190808121407676 and 20200813142301001)National Natural Science Foundation of China(22178223 and 22262010)+1 种基金Guangxi Science and Technology Fund for Distinguished High-Talent Introduction Program(No.RZ2200002233AC22035091).
文摘Rechargeable zinc-air batteries(ZABs)are a promising energy conversion device,which rely critically on electrocatalysts to accelerate their rate-determining reactions such as oxygen reduction(ORR)and oxygen evolution reactions(OER).Herein,we fabricate a range of bifunctional M-N-C(metal-nitrogen-carbon)catalysts containing M-Nx coordination sites and M/MxC nanoparticles(M=Co,Fe,and Cu)using a new class ofγ-cyclodextrin(CD)based metal-organic framework as the precursor.With the two types of active sites interacting with each other in the catalysts,the obtained Fe@C-FeNC and Co@C-CoNC display superior alkaline ORR activity in terms of low half-wave(E1/2)potential(~0.917 and 0.906 V,respectively),which are higher than Cu@C-CuNC(~0.829 V)and the commercial Pt/C(~0.861 V).As a bifunctional electrocatalyst,the Co@C-CoNC exhibits the best performance,showing a bifunctional ORR/OER overpotential(ΔE)of~0.732 V,which is much lower than that of Fe@C-FeNC(~0.831 V)and Cu@C-CuNC(~1.411 V),as well as most of the robust bifunctional electrocatalysts reported to date.Synchrotron X-ray absorption spectroscopy and density functional theory simulations reveal that the strong electronic correlation between metallic Co nanoparticles and the atomic Co-N4 sites in the Co@C-CoNC catalyst can increase the d-electron density near the Fermi level and thus effectively optimize the adsorption/desorption of intermediates in ORR/OER,resulting in an enhanced bifunctional electrocatalytic performance.The Co@C-CoNC-based rechargeable ZAB exhibited a maximum power density of 162.80 mW cm^(−2) at 270.30 mA cm^(−2),higher than the combination of commercial Pt/C+RuO2(~158.90 mW cm^(−2) at 265.80 mA cm^(−2))catalysts.During the galvanostatic discharge at 10 mA cm^(−2),the ZAB delivered an almost stable discharge voltage of 1.2 V for~140 h,signifying the virtue of excellent bifunctional ORR/OER electrocatalytic activity.
基金supported in part by the IEA/EBC/Annex57 Committee of Japan,organized through the IBEC(Institute for Building Environment and Energy Conservation).
文摘The embodied energy/CO2 of buildings in China and Japan, which reflects the characteristic industrial efficiency ofbui｜ding materials, is described in this paper. The energy consumption and CO2 intensities for the dominant materials used in buildings are derived from the energy consumption in factories, and the energy consumption to produce equipment is derived from IO （input/output） analysis in order to compare the embodied energy/CO2 for buildings between China and Japan based on the same estimation method. Although the energy consumption of structures in China is two to three times greater than in Japan, the interior finish and air conditioning equipment, for example, are simpler and smaller. As a result, the embodied energy/CO2 of office buildings in China is only 10% to 20% greater than that of Japanese office buildings. Thus, the embodied energy/CO2 of buildings depends on both industrial efficiencies and building design trends of the country.
文摘In this study, we looked at a method quantifying EEC （embodied energy and CO2） and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the covering thickness of concrete for reinforcing bars and the earthquake-resistant strength are methods to increase the durability of the structure. The calculation method to obtain the quantity of concrete and reinforcing bars is provided. The EEC increase is evaluated from the 2005 input-output table in Japan. These results show that EE （embodied energy） in the construction phase is increased by 11% to 20% and EC （embodied CO2） 17% to 32%. However, annual EE is reduced 66% to 72% and EC 70% to 79%,
基金the financial support from National Natural Science Foundation of China[grant number 52171130(S.Ni)]Huxiang Youth Talents Support Program[grant number 2021RC3002(S.Ni)]+1 种基金the financial support from the Research Office and Research Institute of Advanced Manufacturing of the Hong Kong Polytechnic University[grant numbers P0039966 and P0041361]support from the Royal Society in the UK under Grant No.IES\R3\223190.
文摘CoCrMoW alloys with different nitrogen(N)additions(0,0.05,0.1,and 0.2 wt%)were prepared via laser powder bed fusion(LPBF).The effects of N content on the microstructure and mechanical properties were investigated.The results indicate that the LPBFed CoCrMoW alloy with 0.1 wt%N addition(0.1 N alloy)shows the best combination of mechanical properties with a yield strength of~983 MPa and an elongation of~19%.Both the LPBF process and the N addition impose great effects on suppressing theγtoεmartensitic transformation,resulting in a decrease in the width and amount ofεlaths/stacking faults.Besides,the N addition promotes the segregation of elements Mo,W,and Si along the cellular sub-grain boundaries(CBs),forming fine and discontinuous precipitates rich in Mo,W and Si along the CBs in the 0.1 N alloy,but dense and continuous(Mo,W)5Si_(3)precipitates along the CBs in the 0.2 N alloy.The(Mo,W)5Si_(3)precipitates with a tetragonal structure were observed and characterized for the first time in the Co-Cr based alloys.The negative mixing enthalpy between the non-metallic elements N,Si and the metallic elements Mo,W,Cr,and the rapid solidification induced segregation of high melting point elements such as Mo and W along CBs during LPBF process,synergistically contribute to the chemical heterogeneity in the alloys.The pure FCC matrix,the slightly increased segregation of Mo,W,Si elements and fine precipitates along the CBs contribute to the good combination of strength and elongation of the 0.1 N alloy.However,though pure FCC phase was present in the 0.2 N alloy,the dense and continuous(Mo,W)5Si_(3)precipitates along CBs acted as nucleation sites for cracks,deteriorating the elongation of the alloy.Overall,it is possible to tune the mechanical properties of the LPBFed CoCrMoW alloy by adjusting the local chemical heterogeneity.
文摘Structural Health Monitoring(SHM)is the process of collecting,interpreting and analysing data from structures in order to determine its health status and the remaining life span.Composite materials have been extensively use in recent years in several industries with the aim at reducing the total weight of structures while improving their mechanical properties.However,composite materials are prone to develop damage when subjected to low to medium impacts(i.e.1-10 m/s and 11-30 m/s respectively).Hence,the need to use SHM techniques to detect damage at the incipient initiation in composite materials is of high importance.Despite the availability of several SHM methods for the damage identification in composite structures,no single technique has proven suitable for all circumstances.It must be noted that the amount of techniques available nowadays is too extensive to be comprehensively reviewed in a single paper.Therefore,the focus will be on techniques that can serve as a starting point for studies focusing on damage detection,localisation,assessment and prognosis on certain kinds of structures.Thus,the line of thought behind the search and the structure of this review is a result of objectives beyond the scope of the paper itself.Nevertheless,it was considered that,once the above was understood,an updated synopsis such as this could also be useful for other researchers in the same field.
文摘This study presents a development on a time efficient approach to measure the Acoustic Impedance of Industrial Insulating materials using an impedance tube with single moveable microphone and a white noise generator. The standing wave method is used to measure the acoustic properties (absorption coefficient and acoustic impedance) of sound absorbing materials. In order to use a burst of white noise instead of individual stationary sine waves, a signal processing technique was developed. The algorithm is based on the equation of simple harmonic motion, but uses distance as a variable, instead of time. This innovative method allows measuring at frequency resolutions as low as 5 Hz in a reasonably short amount of time. This is an advantage, as the classical standing wave method uses frequency resolutions of one-third of octaves for measurements, as otherwise time would be prohibitive. Experimental results are validated with those measured with the sine wave generator using one-third of octave frequencies by comparing their behaviours.
文摘The objective of this research is to quantify the EEC （embodied energy/CO2） of a building. The EEC represents the energy consumption and CO2 emissions at individual phases of a building＇s life-cycle, such as construction （including manufacture of materials and equipment）, renewal （including repair work） and demolition. Energy and CO2 emission intensities in terms of 401 sectors were calculated, using the 2005 I-O （input-output） table in Japan. According to our case study conducted from the construction phase to demolition, the EC （embodied CO2） of an office building used for 60 years is 12,044 t-CO2 and 1,093 kg-CO2/m^2 in total. CO2 equivalent emissions （CO2e） by Freon gases, contained in building materials, equipment and devices, were also calculated. As the results, CO2e by insulators was 2% of the building＇s EC and CO2e by refrigerants was 9%-12% of the building＇s EC. It is important to keep reducing emissions of Freon gases contained in refrigerators.
文摘In July 2009, the 2005 basic Japanese input/output table was publicized together with its physical transaction table. This research paper analyzed the 2005 IO （input/output） table to create building industry-related intensities and, at the same time, compared the building industry with industries at large for distribution margins and transportation. The analysis of distribution margins separately for middle and purchaser margins found that middle margins in the building industry are minor at 35% of the averages for all industries, while purchaser margins are sizable at 1.8 times, proving that it is an industry for which local production for local consumption is quite effective. CO2 emissions resulting from transportation in the building industry were calculated and concisely characterized. Although the ratio of transportation CO2 emissions to total CO2 emissions in each industry finds almost no difference between general industries and the building industry, transportation CO2 emissions per production value are two to three times heavier than those from general industries to be justified as a transportation-intensive industry.
基金supported by the Ministry of Education,Singapore(Research Centre of Excellence award to the Institute for Functional Intelligent Materials,I-FIM,project No.EDUNC-33-18-279-V12)from the Royal Society(UK,grant number RSRP∖R∖190000).
文摘Self-healing(SH)polymeric composites hold the promise of revolutionizing material performance and durability,but the challenge lies in achieving a delicate balance between healing efficiency and mechanical strength.Healing processes typically require dynamic,reversible bonds,which can weaken overall material strength,whereas robust materials rely on strong covalent bonds that resist healing.2D materials offer a solution by acting as nanofillers that not only improve mechanical properties but also introduce multifunctional benefits like electrical and thermal conductivity,responsiveness to stimuli,and enhanced barrier properties.Depending on their surface chemistry,thesematerials can either actively participate in the healing process or passively reinforce the polymer matrix.This review examines recent advancements in SH polymer composites enhanced with 2D fillers,exploring how factors like filler type,surface interactions,and loading levels impact both healing efficiency and mechanical strength.It compares the contributions of various 2D materials,identifying similarities and critical differences in their roles within polymermatrices.The article also highlights the need for standardized testing and advanced characterization techniques to better understand interfacial properties and healing mechanisms.By addressing current knowledge gaps and proposing future research directions,this review provides a comprehensive resource for advancing SH polymer systems,particularly in the integration of 2D materials for applications ranging from aerospace to electronics.
基金financially supported by the National Natural Science Foundation of China (No.52274294)the Fundamental Research Funds for the Central Universities (No.N2124007-1)。
文摘The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped carbon layer(FCO@NC)was prepared using Fe-Co-based Prussian blue analogs(PBA)as a precursor.During the synthesis,dopamine was the carbon and nitrogen source.The reducing atmosphere was assured via NH_3/Ar,which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity.When used as anode materials for LIBs,the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g^(-1)at 0.3 A·g^(-1)after200 cycles with a capacity retention rate of 80.4%and426.76 mAh·g^(-1)after 500 cycles at a high current density of 1 A·g^(-1).It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability,and the heat treatment in NH_(3)/Ar atmosphere contributes to the oxygen vacancy content of the electrode materials,further facilitating its conductivity and electrochemical performance.
基金the Foundation for the Promotion in Asturias of the Applied Scientific Research and Technology(FICYT)and the Ministry of Economy and Competitiveness(Spain)for supporting this work in the framework of the research projects Lubrication and Surface Technology(GRUPIN14-023)STARLUBE(DPI2013-48348-C2-1-R)
文摘The ionic liquid(IL) tributylmethylammonium bis(trifluoromethylsulfonyl)amide([N4441][NTf2]) was used as neat lubricant and as an additive(1.5 wt%) in a polar oil to study its friction and wear reducing properties.Tribological tests were completed for 90 minutes at room temperature and 100 °C in a reciprocating configuration at loads of 30 and 70 N,10 Hz-frequency,and 4 mm stroke length.Wear volume was measured by confocal microscopy and the surface-IL interaction determined by XPS.The main findings were that neat IL showed the best tribological behavior;the IL-containing mixture behaved similar to the base oil regarding friction,however outperformed the antiwear behavior of the base oil under higher temperature;surface-IL chemical interaction was found mainly at 100 °C.
文摘Industrial process plants use emergency shutdown valves(ESDVs)as safety barriers to protect against hazardous events,bringing the plant to a safe state when potential danger is detected.These ESDVs are used extensively in offshore oil and gas processing plants and have been mandated in the design of such systems from national and international standards and legislation.This paper has used actual ESDV operating data from four mid/late life oil and gas production platforms in the North Sea to research operational relationships that are of interest to those responsible for the technical management and operation of ESDVs.The first of the two relationships is between the closure time(CT)of the ESDV and the time it remains in the open position,prior to the close command.It has been hypothesised that the CT of the ESDV is affected by the length of time that it has been open prior to being closed(Time since the last stroke).In addition to the general analysis of the data series,two sub-categories were created to further investigate this possible relationship for CT and these are“above mean”and“below mean”.The correlations(Pearson's based)resulting from this analysis are in the“weak”and“very weak”categories.The second relationship investigated was the effect of very frequent closures to assess if this improves the CT.ESDV operational records for six subjects were analysed to find closures that occurred within a 24 h period of each other.However,no discriminating trend was apparent where CT was impacted positively or negatively by the frequent closure group.It was concluded that the variance of ESDV closure time cannot be influenced by the technical management of the ESDV in terms of scheduling the operation of the ESDV.
文摘Synthesis of ultrathin heterostructures has received much attention in the recent past due to their unique physical and chemical properties.In this work,we report the synthesis of Fe_(2)TiO_(5)–TiO_(2)heterostructures using a simple hydrothermal technique employing natural ilmenite as the source.Hierarchically arranged nanostructures with interconnected nano-petals of thickness around 50 nm are obtained.The electrocatalytic properties of the synthesized Fe_(2)TiO_(5)–TiO_(2)heterostructures are enhanced following the cathodization technique.The observed enhancement in the synthesized materials’electrocatalytic property can be attributed to the defect-rich Fe_(2-x)TiO_(5-x)-TiO_(2-x)heterostructures.The current approach and technique discussed in this work offer a simple method to synthesize a nanostructured heterostructure material and create defects for enhancing electrocatalytic activity.
