Objective:To correlate the utility of the Fundamentals of Laparoscopic Surgery(FLS)manual skills program with the Objective Structured Assessment of Technical Skills(OSATS)global rating scale in evaluating operative p...Objective:To correlate the utility of the Fundamentals of Laparoscopic Surgery(FLS)manual skills program with the Objective Structured Assessment of Technical Skills(OSATS)global rating scale in evaluating operative performance.Methods:The Asian Urological Surgery Training and Educational Group(AUSTEG)Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training.Delegates’basic laparoscopic skills were assessed using three different training models(peg transfer,precision cutting,and intra-corporeal suturing).They also performed live porcine laparoscopic surgery at the same workshop.Live surgery skills were assessed by blinded faculty using the OSATS rating scale.Results:From March 2016 to March 2019,a total of 81 certified urologists participated in the course,with a median of 5 years of post-residency experience.Although differences in task time did not reach statistical significance,those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks.However,they took longer to complete the precision cutting task than participants with less experience.Overall OSATS scores correlated weakly with all three FLS tasks(peg transfer time:r=0.331,r^(2)=0.110;precision cutting time:r=0.240,r^(2)=0.058;suturing with intracorporeal knot time:r=0.451,r^(2)=0.203).Conclusion:FLS task parameters did not correlate strongly with OSATS globing rating scale performance.Although FLS task models demonstrated strong validity,it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence,as evaluated by FLS and OSATS,respectively.展开更多
Objective:Clinical education plays a key role in preparing students for patient care.Laparoscopy is one of the most important minimally invasive surgeries(MISs)wherein surgical technologists are responsible for camera...Objective:Clinical education plays a key role in preparing students for patient care.Laparoscopy is one of the most important minimally invasive surgeries(MISs)wherein surgical technologists are responsible for camera navigation and assistant surgeons are responsible for peg transfer.Therefore,it is necessary to improve the attitude of the operating room students toward these skills during their study period.The present study was conducted to determine the effect of simulating training in the fundamentals of laparoscopic surgery(FLS)on the attitude of the operating room students.Methods:This interventional study was conducted on 28 operating room students of Iran University of Medical Sciences in 2019.The census sampling method was used.The data-collection tool included the“Intrinsic motivation inventory(IMI)questionnaire.”The educational intervention was carried out in theoretical(booklet design)and practical(simulation)sections.Data analysis was carried out using descriptive and inferential analyses including the paired t-test,Mann–Whitney U test,and independent t-test.The collected data were analyzed using R and SPSS software.P-value<0.05 was considered as the significant level.Results:The mean±SD of the participants'age was 22.93±2.14 years,and the majority of them were women(67.9%).There was a significant difference in the mean scores of students'attitudes toward the FLS before and after the educational intervention(P<0.001)in all dimensions(interest,perceived competence,perceived choice,and tension).There was also a significant correlation between gender and interest dimension(P=0.005).Conclusions:The results of the present study showed that simulating the training FLS curriculum positively affects students'attitudes.Therefore,the researchers suggest that for creating a positive attitude,increasing students'interest in laparoscopic surgery,and ensuring a more effective presence in the operating room,this training should be considered in the operating room curriculum.展开更多
Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and i...Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation.Density functional theory(DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors,which greatly expands the breadth and depth of flotation studies.This review systematically summarizes the advances of flotation research based on DFT studies,including the study of mineral crystal chemistry represented by the theory of lattice defects,mineral surface hydration such as hydrophilicity and hydrophobicity,surface regulation mechanism,and collecting mechanism based on surface adsorption theory.More significantly,it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.展开更多
Based on the floods landslides commensurability system, the paper presents and discusses the disasters/hazards with comprehensive interaction and erosional processes. However, people are not enough to get their possi...Based on the floods landslides commensurability system, the paper presents and discusses the disasters/hazards with comprehensive interaction and erosional processes. However, people are not enough to get their possibility for the sustainability. They have had so many disasters to meet and to control continuously. Finally, the fundamentals should be built up with nonlinear solutions of landsliding problems; the events of geomagnetism anomaly should be considered.展开更多
According to the requirement of New Engineering Disciplines initiated by the Ministry of Education of China,the course of Programming Fundamentals has been reformed in ethnic university to satisfy the standard of New ...According to the requirement of New Engineering Disciplines initiated by the Ministry of Education of China,the course of Programming Fundamentals has been reformed in ethnic university to satisfy the standard of New Engineering Certification.The reform is implemented in teaching content,implementation in both theoretical and experimental classes,teaching assessment and teacher training.展开更多
The paper aims to investigate the current account imbalances in the context of an overview of macroeconomic fundamentals after the liberalization process in Turkey. Two main questions discussed here are： （1） What i...The paper aims to investigate the current account imbalances in the context of an overview of macroeconomic fundamentals after the liberalization process in Turkey. Two main questions discussed here are： （1） What is the link between liberalization and current account imbalances; （2） What kind of mechanisms ensured this link to become a vicious circle. The period after 1989, Turkey was characterized by significant fluctuations in macroeconomic activity by the implementation of liberalization policies. Once financial liberalization is adopted, Turkey faced with a new challenge： large current account deficits. On the other hand, foreign capital inflows aggravated a lending boom. Because of excessive risk taken by banks, interest rates began to rise. As mentioned above, the paper studies Turkey＇s liberalization process with a number of indicators that point to a fragility of the external balance： unhealthy structure of financial sector, particularly banking sector, large fiscal imbalances, low savings and investment rates, unstable GDP growth. Domestic structural features combining with macroeconomic policy stance and political factors are examined as well展开更多
The Fundamentals of Combustion course is an important compulsory course for Energy and Power Engineering Majors under the background of carbon peaking.According to the characteristics of teaching and scientific resear...The Fundamentals of Combustion course is an important compulsory course for Energy and Power Engineering Majors under the background of carbon peaking.According to the characteristics of teaching and scientific research at present,combined with the characteristics of complexity,interdisciplinary and rapid technology update of this course,this paper discusses the teaching content and teaching design of this course to meet the needs of talents of production,teaching and research under the background of new engineering course.It proposes more applicable teaching methods and practical means to broaden students horizons,stimulate students autonomous learning momentum,master the professional knowledge application ability,and cultivate innovative and competitive engineering professionals to adapt to the new energy strategy.展开更多
The overall requirements for standardization work in 2007 are to continuouslypush forward the implementation of the national standardization strategy, to comprehensivelyimprove the effectiveness of standardization in ...The overall requirements for standardization work in 2007 are to continuouslypush forward the implementation of the national standardization strategy, to comprehensivelyimprove the effectiveness of standardization in upgrading product quality, to promote industrialdevelopment, to save resources and build a harmonious society, and to further enhance the strategicposition of China in international trade.The latter is guided by Deng Xiaoping Theory and theimportant concept of 'Three Represents,' as well as having, 'Technological Innovation' as thedriving force, and the intensification of China's national competitive power as the core intent. Tothis end, the following tasks must be undertaken as top priorities.展开更多
In view of the shortcomings of traditional teaching in the Mechanical Design Fundamentals course,the teaching resources are integrated,the teaching content,teaching methods,and assessment methods are reformed,scientif...In view of the shortcomings of traditional teaching in the Mechanical Design Fundamentals course,the teaching resources are integrated,the teaching content,teaching methods,and assessment methods are reformed,scientific research results are introduced into course teaching,and the task-driven teaching practice is applied.These measures have improved classroom activity,stimulated independent learning,and laid the foundation for the cultivation of students’engineering literacy and innovative ability.展开更多
2016,08 Released by Cotton Incorporated Recent price movement After rising throughout July,benchmark prices have been either flat or lower in the first half of August.·Values for the December NY futures contract ...2016,08 Released by Cotton Incorporated Recent price movement After rising throughout July,benchmark prices have been either flat or lower in the first half of August.·Values for the December NY futures contract climbed to levels over 75cents/lb in early August,but have since retreated to values below 71 cents/lb.·The A Index followed a nearly identical pattern as NY futures,with values climbing above 85 cents/lb in early August and then decreasing to levels be-展开更多
2017.11Recent price movement·Most benchmark prices were unchanged over the past month.Only Pakistani prices had any notable movement,increasing slightly.·Values for the NY December contract were range-bound ...2017.11Recent price movement·Most benchmark prices were unchanged over the past month.Only Pakistani prices had any notable movement,increasing slightly.·Values for the NY December contract were range-bound over the past month,holding to levels between 66 and70 cents/lb.Nonetheless,prices migrated towards the lower end of that range in mid-October and then shifted展开更多
Recent price movement Several benchmark prices increased over the past month.NY futures,the A Index,and Pakistani spot prices all rose a few cents/lb,while the CC Index and Indian spot prices were stable.·The Mar...Recent price movement Several benchmark prices increased over the past month.NY futures,the A Index,and Pakistani spot prices all rose a few cents/lb,while the CC Index and Indian spot prices were stable.·The March NY futures contract was the most actively traded contract over the past month.Prices for March futures trended higher from late November through early December,展开更多
Recent price movement All benchmark prices except the CC Index increased over the past month.Prices for the March NY futures contract surged in late December,rising from75 cents/lb to just below 80 cents/lb.Following ...Recent price movement All benchmark prices except the CC Index increased over the past month.Prices for the March NY futures contract surged in late December,rising from75 cents/lb to just below 80 cents/lb.Following that round of increases,展开更多
It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencin...It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencing international crude oil prices and to establish crude oil price models to forecast long-term international crude oil prices. Six explanatory influential variables, namely Dow Jones Indexes, the Organization for Economic Cooperation and Development oil stocks, US rotary rig count, US dollar index, total open interest, which is the total number of outstanding contracts that are held by market participants at the end of each day, and geopolitical instability are specified, and the samples, from January 1990 to August 2017, are divided into six sub-periods. Moreover, the co-integration relationship among variables shows that the contribution ratios of all the variables influencing Brent crude oil prices are in accordance with the corresponding qualitative analysis. Furthermore, from September 2017 to December 2022 outside of the sample, the Vector Autoregressive forecasts show that annually averaged Brent crude oil prices for 2017-2022 would be $53.0, $61.3, $74.4, $90.0, $105.5, and $120.7 per barrel, respectively. The Vector Error Correction forecasts show that annual average Brent crude oil prices for 2017-2022 would be $53.0, $56.5, $58.5, $60.7, $63.0 and $65.4 per barrel, respectively.展开更多
The present market for herbal drugs is estimated about ?40 billion, which is expected to increase by 16% in next 3-4 years. The current production of many Ayurvedic herbs is less than their market demand, which incent...The present market for herbal drugs is estimated about ?40 billion, which is expected to increase by 16% in next 3-4 years. The current production of many Ayurvedic herbs is less than their market demand, which incentivizes adulteration in the Ayurvedic drug supply chain. The present work aims to highlight the most used Ayurvedic plants that have been listed in the International Union for Conservation of Nature's "red list" of endangered or vulnerable plants. The future of Ayurvedic medicines from these listed plants is uncertain, as the collection of herbs from their natural habitat is prohibited and their cultivation does not meet market demands. Many of these plants, such as Taxus baccata and T. wallichiana, are endangered and are only grown in their natural habitats;their cultivation in other areas is impractical. This is the present state, and will worsen as demand continues to grow, with increasing populations and increasing adoption of this system of medicine. It is possible that in coming years most of the Ayurvedic drugs will be adulterated, and will cause only side effects rather than the therapeutic effects. The Ayurvedic fundamentals are under-explored areas where the Ayurvedic practitioners and research scientists can work together. The scientific work on the basic principles will unravel many unknown or little-known facts of this ancient science. Hence, the present review emphasizes the conservation of Ayurvedic herbs, minimization of the use of medicinal plants and the promotion of the research based on Ayurvedic fundamentals.展开更多
The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundame...The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundamental fermions (three leptons and nine quarks) as spheres with non-zero holographic radius. Holographic analysis (based on quantum mechanics, general relativity, thermodynamics, and Shannon information theory) specifies electron mass by five fundamental constants: Planck’s constant ℏ, gravitational constant G, fine structure constant α, cosmological constant Λ, and vacuum energy fraction ΩΛ. Protons and neutrons are composite systems of up and down quarks. Describing forces between quark constituents confined within nucleons as inverse square attractive forces, this alternative model identifies composition factors Cpand Cnto relate proton and neutron masses to electron mass and thus to fundamental constants. An appendix summarizes holographic analyses characterizing astronomical masses at the opposite end of the mass scale for objects in the universe.展开更多
Entering the third year of the most serious economic crisis since the Great Depression, the world economy is still bogged down on the muddy road to recovery. The latest edition of Standard Chartered Bank’s monthly re...Entering the third year of the most serious economic crisis since the Great Depression, the world economy is still bogged down on the muddy road to recovery. The latest edition of Standard Chartered Bank’s monthly report, Global Focus,展开更多
Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demons...Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demonstrating great potential to fulfill unprecedented demand from electronic gadgets,electric vehicles,and grid storage.Despite these good merits,lithium metal suffers from low Coulombic efficiency and dendritic growth,leading to internal short-circuiting of the cell and raising safety concerns about employing lithium metal as an anode.Recently,lithium-tin(Li-Sn)alloys,among other lithium alloys,have emerged as a potential alternative to lithium metal to efficiently suppress the lithium dendrite formation and reduce interfacial resistance for safer and longer-lasting lithium batteries.Accordingly,this work first reviews the fundamentals of Li-Sn alloys,and critically analyzes the failure mechanisms of pristine Li-metal anode and how Li-Sn alloys could overcome those challenges.The subsequent section examines various strategies to synthesize Li-Sn bulk and protection film alloys,followed by an evaluation of symmetric cell performance.Furthermore,the comparative electrochemical performance of full cells against different cathodes and solid electrolytes provides an overview of the present research.Subsequently,advanced characterization techniques were discussed to visualize lithium dendrites directly and quantify the mechanical performance of Li-Sn alloys.Last but not the least,the state-of-the-art progress of applying M-Sn(M=Na and Mg)beyond lithium batteries was summarized.In closing,this work identifies the critical challenges and provides future perspectives on Li-Sn alloy for lithium batteries and beyond.展开更多
Polymer electrolyte membrane(PEM)fuel cells are electrochemical devices that directly convert the chemical energy stored in fuel into electrical energy with a practical conversion efficiency as high as 65%.In the past...Polymer electrolyte membrane(PEM)fuel cells are electrochemical devices that directly convert the chemical energy stored in fuel into electrical energy with a practical conversion efficiency as high as 65%.In the past years,significant progress has been made in PEM fuel cell commercialization.By 2019,there were over 19,000 fuel cell electric vehicles(FCEV)and 340 hydrogen refueling stations(HRF)in the U.S.(~8,000 and 44,respectively),Japan(~3,600 and 112,respectively),South Korea(~5,000 and 34,respectively),Europe(~2,500 and 140,respectively),and China(~110 and 12,respectively).Japan,South Korea,and China plan to build approximately 3,000 HRF stations by 2030.In 2019,Hyundai Nexo and Toyota Mirai accounted for approximately 63%and 32%of the total sales,with a driving range of 380 and 312 miles and a mile per gallon(MPGe)of 65 and 67,respectively.Fundamentals of PEM fuel cells play a crucial role in the technological advancement to improve fuel cell performance/durability and reduce cost.Several key aspects for fuel cell design,operational control,and material development,such as durability,electrocatalyst materials,water and thermal management,dynamic operation,and cold start,are briefly explained in this work.Machine learning and artificial intelligence(AI)have received increasing attention in material/energy development.This review also discusses their applications and potential in the development of fundamental knowledge and correlations,material selection and improvement,cell design and optimization,system control,power management,and monitoring of operation health for PEM fuel cells,along with main physics in PEM fuel cells for physics-informed machine learning.The objective of this review is three fold:(1)to present the most recent status of PEM fuel cell applications in the portable,stationary,and transportation sectors;(2)to describe the important fundamentals for the further advancement of fuel cell technology in terms of design and control optimization,cost reduction,and durability improvement;and(3)to explain machine learning,physics-informed deep learning,and AI methods and describe their significant potentials in PEM fuel cell research and development(R&D).展开更多
文摘Objective:To correlate the utility of the Fundamentals of Laparoscopic Surgery(FLS)manual skills program with the Objective Structured Assessment of Technical Skills(OSATS)global rating scale in evaluating operative performance.Methods:The Asian Urological Surgery Training and Educational Group(AUSTEG)Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training.Delegates’basic laparoscopic skills were assessed using three different training models(peg transfer,precision cutting,and intra-corporeal suturing).They also performed live porcine laparoscopic surgery at the same workshop.Live surgery skills were assessed by blinded faculty using the OSATS rating scale.Results:From March 2016 to March 2019,a total of 81 certified urologists participated in the course,with a median of 5 years of post-residency experience.Although differences in task time did not reach statistical significance,those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks.However,they took longer to complete the precision cutting task than participants with less experience.Overall OSATS scores correlated weakly with all three FLS tasks(peg transfer time:r=0.331,r^(2)=0.110;precision cutting time:r=0.240,r^(2)=0.058;suturing with intracorporeal knot time:r=0.451,r^(2)=0.203).Conclusion:FLS task parameters did not correlate strongly with OSATS globing rating scale performance.Although FLS task models demonstrated strong validity,it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence,as evaluated by FLS and OSATS,respectively.
基金supported by the Iran University of Medical Science。
文摘Objective:Clinical education plays a key role in preparing students for patient care.Laparoscopy is one of the most important minimally invasive surgeries(MISs)wherein surgical technologists are responsible for camera navigation and assistant surgeons are responsible for peg transfer.Therefore,it is necessary to improve the attitude of the operating room students toward these skills during their study period.The present study was conducted to determine the effect of simulating training in the fundamentals of laparoscopic surgery(FLS)on the attitude of the operating room students.Methods:This interventional study was conducted on 28 operating room students of Iran University of Medical Sciences in 2019.The census sampling method was used.The data-collection tool included the“Intrinsic motivation inventory(IMI)questionnaire.”The educational intervention was carried out in theoretical(booklet design)and practical(simulation)sections.Data analysis was carried out using descriptive and inferential analyses including the paired t-test,Mann–Whitney U test,and independent t-test.The collected data were analyzed using R and SPSS software.P-value<0.05 was considered as the significant level.Results:The mean±SD of the participants'age was 22.93±2.14 years,and the majority of them were women(67.9%).There was a significant difference in the mean scores of students'attitudes toward the FLS before and after the educational intervention(P<0.001)in all dimensions(interest,perceived competence,perceived choice,and tension).There was also a significant correlation between gender and interest dimension(P=0.005).Conclusions:The results of the present study showed that simulating the training FLS curriculum positively affects students'attitudes.Therefore,the researchers suggest that for creating a positive attitude,increasing students'interest in laparoscopic surgery,and ensuring a more effective presence in the operating room,this training should be considered in the operating room curriculum.
基金financially supported by the Natural Science Foundation of China under grants: U20A20269, 51874106, and 51574092。
文摘Flotation is a complex process that occurs in solid-liquid-gas multiphase systems,and its main factors include the minerals,separation medium,as well as various flotation reagents.The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation.Density functional theory(DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors,which greatly expands the breadth and depth of flotation studies.This review systematically summarizes the advances of flotation research based on DFT studies,including the study of mineral crystal chemistry represented by the theory of lattice defects,mineral surface hydration such as hydrophilicity and hydrophobicity,surface regulation mechanism,and collecting mechanism based on surface adsorption theory.More significantly,it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.
文摘Based on the floods landslides commensurability system, the paper presents and discusses the disasters/hazards with comprehensive interaction and erosional processes. However, people are not enough to get their possibility for the sustainability. They have had so many disasters to meet and to control continuously. Finally, the fundamentals should be built up with nonlinear solutions of landsliding problems; the events of geomagnetism anomaly should be considered.
基金supported by the Scientific Research Foundation of Inner Mongolia of China(KCBJ2018029)the CRP of CAS Key Laboratory of Solar Activity of National Astronomical Observatories(KLSA201905).
文摘According to the requirement of New Engineering Disciplines initiated by the Ministry of Education of China,the course of Programming Fundamentals has been reformed in ethnic university to satisfy the standard of New Engineering Certification.The reform is implemented in teaching content,implementation in both theoretical and experimental classes,teaching assessment and teacher training.
文摘The paper aims to investigate the current account imbalances in the context of an overview of macroeconomic fundamentals after the liberalization process in Turkey. Two main questions discussed here are： （1） What is the link between liberalization and current account imbalances; （2） What kind of mechanisms ensured this link to become a vicious circle. The period after 1989, Turkey was characterized by significant fluctuations in macroeconomic activity by the implementation of liberalization policies. Once financial liberalization is adopted, Turkey faced with a new challenge： large current account deficits. On the other hand, foreign capital inflows aggravated a lending boom. Because of excessive risk taken by banks, interest rates began to rise. As mentioned above, the paper studies Turkey＇s liberalization process with a number of indicators that point to a fragility of the external balance： unhealthy structure of financial sector, particularly banking sector, large fiscal imbalances, low savings and investment rates, unstable GDP growth. Domestic structural features combining with macroeconomic policy stance and political factors are examined as well
基金Supported by Ideological and Political Teaching Reform Project of Yunnan Agricultural University in 2022(YAUKCSZJG0050)Ideological and Political Teaching Reform Project of Yunnan Agricultural University in 2023(YNAUKCSZJG2023045)First-class Course Construction Project of Yunnan Agricultural University in 2023(2023YLKC019).
文摘The Fundamentals of Combustion course is an important compulsory course for Energy and Power Engineering Majors under the background of carbon peaking.According to the characteristics of teaching and scientific research at present,combined with the characteristics of complexity,interdisciplinary and rapid technology update of this course,this paper discusses the teaching content and teaching design of this course to meet the needs of talents of production,teaching and research under the background of new engineering course.It proposes more applicable teaching methods and practical means to broaden students horizons,stimulate students autonomous learning momentum,master the professional knowledge application ability,and cultivate innovative and competitive engineering professionals to adapt to the new energy strategy.
文摘The overall requirements for standardization work in 2007 are to continuouslypush forward the implementation of the national standardization strategy, to comprehensivelyimprove the effectiveness of standardization in upgrading product quality, to promote industrialdevelopment, to save resources and build a harmonious society, and to further enhance the strategicposition of China in international trade.The latter is guided by Deng Xiaoping Theory and theimportant concept of 'Three Represents,' as well as having, 'Technological Innovation' as thedriving force, and the intensification of China's national competitive power as the core intent. Tothis end, the following tasks must be undertaken as top priorities.
基金The Education and Teaching Research Project of National University of Defense Technology(Project Number:U2020103)。
文摘In view of the shortcomings of traditional teaching in the Mechanical Design Fundamentals course,the teaching resources are integrated,the teaching content,teaching methods,and assessment methods are reformed,scientific research results are introduced into course teaching,and the task-driven teaching practice is applied.These measures have improved classroom activity,stimulated independent learning,and laid the foundation for the cultivation of students’engineering literacy and innovative ability.
文摘2016,08 Released by Cotton Incorporated Recent price movement After rising throughout July,benchmark prices have been either flat or lower in the first half of August.·Values for the December NY futures contract climbed to levels over 75cents/lb in early August,but have since retreated to values below 71 cents/lb.·The A Index followed a nearly identical pattern as NY futures,with values climbing above 85 cents/lb in early August and then decreasing to levels be-
文摘2017.11Recent price movement·Most benchmark prices were unchanged over the past month.Only Pakistani prices had any notable movement,increasing slightly.·Values for the NY December contract were range-bound over the past month,holding to levels between 66 and70 cents/lb.Nonetheless,prices migrated towards the lower end of that range in mid-October and then shifted
文摘Recent price movement Several benchmark prices increased over the past month.NY futures,the A Index,and Pakistani spot prices all rose a few cents/lb,while the CC Index and Indian spot prices were stable.·The March NY futures contract was the most actively traded contract over the past month.Prices for March futures trended higher from late November through early December,
文摘Recent price movement All benchmark prices except the CC Index increased over the past month.Prices for the March NY futures contract surged in late December,rising from75 cents/lb to just below 80 cents/lb.Following that round of increases,
基金supported by the National Science Foundation of China(NSFC No.41271551/71201157)the National Key Research and Development Program(2016YFA0602700)
文摘It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencing international crude oil prices and to establish crude oil price models to forecast long-term international crude oil prices. Six explanatory influential variables, namely Dow Jones Indexes, the Organization for Economic Cooperation and Development oil stocks, US rotary rig count, US dollar index, total open interest, which is the total number of outstanding contracts that are held by market participants at the end of each day, and geopolitical instability are specified, and the samples, from January 1990 to August 2017, are divided into six sub-periods. Moreover, the co-integration relationship among variables shows that the contribution ratios of all the variables influencing Brent crude oil prices are in accordance with the corresponding qualitative analysis. Furthermore, from September 2017 to December 2022 outside of the sample, the Vector Autoregressive forecasts show that annually averaged Brent crude oil prices for 2017-2022 would be $53.0, $61.3, $74.4, $90.0, $105.5, and $120.7 per barrel, respectively. The Vector Error Correction forecasts show that annual average Brent crude oil prices for 2017-2022 would be $53.0, $56.5, $58.5, $60.7, $63.0 and $65.4 per barrel, respectively.
基金funded by National Medicinal Plants Board, Ministry of Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy, Government of India, with grant number Z.18017/ 187/CSS/R&D/UK-01/2017-18-NMPB-IV A
文摘The present market for herbal drugs is estimated about ?40 billion, which is expected to increase by 16% in next 3-4 years. The current production of many Ayurvedic herbs is less than their market demand, which incentivizes adulteration in the Ayurvedic drug supply chain. The present work aims to highlight the most used Ayurvedic plants that have been listed in the International Union for Conservation of Nature's "red list" of endangered or vulnerable plants. The future of Ayurvedic medicines from these listed plants is uncertain, as the collection of herbs from their natural habitat is prohibited and their cultivation does not meet market demands. Many of these plants, such as Taxus baccata and T. wallichiana, are endangered and are only grown in their natural habitats;their cultivation in other areas is impractical. This is the present state, and will worsen as demand continues to grow, with increasing populations and increasing adoption of this system of medicine. It is possible that in coming years most of the Ayurvedic drugs will be adulterated, and will cause only side effects rather than the therapeutic effects. The Ayurvedic fundamentals are under-explored areas where the Ayurvedic practitioners and research scientists can work together. The scientific work on the basic principles will unravel many unknown or little-known facts of this ancient science. Hence, the present review emphasizes the conservation of Ayurvedic herbs, minimization of the use of medicinal plants and the promotion of the research based on Ayurvedic fundamentals.
文摘The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundamental fermions (three leptons and nine quarks) as spheres with non-zero holographic radius. Holographic analysis (based on quantum mechanics, general relativity, thermodynamics, and Shannon information theory) specifies electron mass by five fundamental constants: Planck’s constant ℏ, gravitational constant G, fine structure constant α, cosmological constant Λ, and vacuum energy fraction ΩΛ. Protons and neutrons are composite systems of up and down quarks. Describing forces between quark constituents confined within nucleons as inverse square attractive forces, this alternative model identifies composition factors Cpand Cnto relate proton and neutron masses to electron mass and thus to fundamental constants. An appendix summarizes holographic analyses characterizing astronomical masses at the opposite end of the mass scale for objects in the universe.
文摘Entering the third year of the most serious economic crisis since the Great Depression, the world economy is still bogged down on the muddy road to recovery. The latest edition of Standard Chartered Bank’s monthly report, Global Focus,
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Mitacs Accelerate,Canada Foundation for Innovation(CFI),B.C.Knowledge Development Fund(BCKDF)Fenix Advanced Materials,and the University of British Columbia(UBC).
文摘Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demonstrating great potential to fulfill unprecedented demand from electronic gadgets,electric vehicles,and grid storage.Despite these good merits,lithium metal suffers from low Coulombic efficiency and dendritic growth,leading to internal short-circuiting of the cell and raising safety concerns about employing lithium metal as an anode.Recently,lithium-tin(Li-Sn)alloys,among other lithium alloys,have emerged as a potential alternative to lithium metal to efficiently suppress the lithium dendrite formation and reduce interfacial resistance for safer and longer-lasting lithium batteries.Accordingly,this work first reviews the fundamentals of Li-Sn alloys,and critically analyzes the failure mechanisms of pristine Li-metal anode and how Li-Sn alloys could overcome those challenges.The subsequent section examines various strategies to synthesize Li-Sn bulk and protection film alloys,followed by an evaluation of symmetric cell performance.Furthermore,the comparative electrochemical performance of full cells against different cathodes and solid electrolytes provides an overview of the present research.Subsequently,advanced characterization techniques were discussed to visualize lithium dendrites directly and quantify the mechanical performance of Li-Sn alloys.Last but not the least,the state-of-the-art progress of applying M-Sn(M=Na and Mg)beyond lithium batteries was summarized.In closing,this work identifies the critical challenges and provides future perspectives on Li-Sn alloy for lithium batteries and beyond.
文摘Polymer electrolyte membrane(PEM)fuel cells are electrochemical devices that directly convert the chemical energy stored in fuel into electrical energy with a practical conversion efficiency as high as 65%.In the past years,significant progress has been made in PEM fuel cell commercialization.By 2019,there were over 19,000 fuel cell electric vehicles(FCEV)and 340 hydrogen refueling stations(HRF)in the U.S.(~8,000 and 44,respectively),Japan(~3,600 and 112,respectively),South Korea(~5,000 and 34,respectively),Europe(~2,500 and 140,respectively),and China(~110 and 12,respectively).Japan,South Korea,and China plan to build approximately 3,000 HRF stations by 2030.In 2019,Hyundai Nexo and Toyota Mirai accounted for approximately 63%and 32%of the total sales,with a driving range of 380 and 312 miles and a mile per gallon(MPGe)of 65 and 67,respectively.Fundamentals of PEM fuel cells play a crucial role in the technological advancement to improve fuel cell performance/durability and reduce cost.Several key aspects for fuel cell design,operational control,and material development,such as durability,electrocatalyst materials,water and thermal management,dynamic operation,and cold start,are briefly explained in this work.Machine learning and artificial intelligence(AI)have received increasing attention in material/energy development.This review also discusses their applications and potential in the development of fundamental knowledge and correlations,material selection and improvement,cell design and optimization,system control,power management,and monitoring of operation health for PEM fuel cells,along with main physics in PEM fuel cells for physics-informed machine learning.The objective of this review is three fold:(1)to present the most recent status of PEM fuel cell applications in the portable,stationary,and transportation sectors;(2)to describe the important fundamentals for the further advancement of fuel cell technology in terms of design and control optimization,cost reduction,and durability improvement;and(3)to explain machine learning,physics-informed deep learning,and AI methods and describe their significant potentials in PEM fuel cell research and development(R&D).
