A new method for the determination of the critical slip surfaces of slopes is proposed in this paper. In this paper, the original critical slip field method is extended in terms of the total residual moment, values of...A new method for the determination of the critical slip surfaces of slopes is proposed in this paper. In this paper, the original critical slip field method is extended in terms of the total residual moment, values of residual work as well as the unbalanced thrust force at the exit point for a given non-circular slip surface. The most critical slip surface with the maximum representative value for a prescribed factor of safety will be optimized and located using the harmony search algorithm. The prescribed factor of safety is modified with certain tiny interval in order to find the critical slip surface where the maximum representative value is zero. The aforementioned approach to the location of the critical slip surface is greatly different from the traditional limit equilibrium procedure. Three typical soil slopes are evaluated by use of the proposed method, and the comparisons with the classical approaches have illustrated the applicability of the proposed method.展开更多
This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that c...This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser＇s vertical distances, horizontal offsets, riser＇s weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR.展开更多
In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory ...In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory of genus, we obtain several results under different conditions.展开更多
With the rapid development of economy and the intensification of market competition, project management involves various aspects of social development. The limitations of traditional project scheduling management meth...With the rapid development of economy and the intensification of market competition, project management involves various aspects of social development. The limitations of traditional project scheduling management methods are becoming more and more obvious. It is extremely urgent to create and apply new management technologies. According to the constraint theory, critical chain method is a method of controlling a project, which can greatly shorten the completion period of the project and reduce the cost of the enterprise. Firstly, the shortcomings of traditional project scheduling management methods are analyzed, and the importance of adopting key chain technology is pointed out. Secondly, the content of the basic chain method is summarized. Finally, the problems existing in the application of critical chain method are analyzed.展开更多
Objective: to analyze the effect and value of intervention and guidance of nursing scoring method for children with critical diseases in child care. Methods: the samples were taken from 100 critically ill children adm...Objective: to analyze the effect and value of intervention and guidance of nursing scoring method for children with critical diseases in child care. Methods: the samples were taken from 100 critically ill children admitted to our hospital from January 2020 to June 2021. According to the different nursing intervention methods, the patients were divided into the control group (routine nursing) and the research group (critical illness nursing score method intervention), with a single group of 50 cases. The data differences such as the incidence of complications, severity of illness, blood gas index and nursing satisfaction were observed and compared. Results: the total incidence rate of heart failure, potential respiratory failure, compensatory shock and irreversible organ failure in the study group was 6.00% significantly lower than that in the control group by 20.00% (P < 0.05). After the intervention, APACHE Ⅱ score and SOFA score of the two groups were lower than before the intervention, and the study group was significantly lower than the control group (P < 0.05). After the intervention, the oxygen partial pressure and carbon dioxide partial pressure of the two groups were better than before the intervention, and the research group was significantly better than the control group (p < 0.05). The satisfaction rate of the research group's family members to the nursing service was 96.00% higher than that of the control group's 84.00% (p < 0.05). Compared with the control group, the study group had higher scores in basic nursing, ward management, nursing safety and nursing documents (p < 0.05). Conclusion: the pediatric critical illness nursing score method has good intervention and guidance value for pediatric nursing, which not only can reduce the incidence of complications, but also can significantly improve the severity of the illness, blood gas indicators, and enhance the satisfaction of family members to the nursing service and the quality of nursing. It is worthy of clinical reference and promotion.展开更多
Climate change and human activities have led to desertification and decreased land productivity,significantly affecting human livelihoods in desert regions.Identifying suitable areas for cultivating economic and nativ...Climate change and human activities have led to desertification and decreased land productivity,significantly affecting human livelihoods in desert regions.Identifying suitable areas for cultivating economic and native plants based on ecological capacity,biological restoration,and risk management can be valuable tools for combating desertification.In this study,we identified suitable areas for the growth of economic and medicinal Moringa peregrina trees in desert regions of Sistan and Baluchestan Province,southern Iran,using library research and field methods.We also assessed the economic involvement of local communities in areas under different topographic conditions(namely flat area,undulating area,rolling area,moderately sloping area,and steep area)in the study area.Financial indicators such as the net present value(NPV),benefit-cost ratio(BCR),internal rate of return(IRR),and return on investment(ROI)were calculated for areas under various topographic conditions in the study area.The rolling area with results of NPV(6142.75 USD),IRR(103.38),BCR(5.38),and ROI(in the 3rd year)was the best region for investing and cultivating M.peregrina.The minimum economic level varied from 0.80 hm2 in the flat area to 21.60 hm2 in the steep area.Also,approximately 5,314,629.51 hm2 of desert lands in the study area were deemed suitable for M.peregrina cultivation,benefiting around 1,743,246 households in the study area.Cultivating M.peregrina in southern Iran can positively affect local communities and help preserve land from erosion.Our study will provide theoretical support for planting native species in other degraded desert regions to enhance ecosystem services and the well-being of indigenous populations.展开更多
With the continuous promotion of the Belt and Road initiative,the sporting goods manufacturing industry,as a key sector of Chinese enterprises’“going global”strategy,is actively expanding the markets of countries a...With the continuous promotion of the Belt and Road initiative,the sporting goods manufacturing industry,as a key sector of Chinese enterprises’“going global”strategy,is actively expanding the markets of countries along the Belt and Road.However,there are significant differences in political,economic,and social environments among countries along the Belt and Road,which bring considerable uncertainties to the transnational investment of enterprises.Based on the investment environment of 70 countries along the Belt and Road,this paper constructs a risk evaluation index system including five dimensions:political and legal,economic and financial,socio-cultural,investment environment,and bilateral relations.The Criteria Importance Through Intercriteria Correlation(CRITIC)method is used to determine weight,Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method is employed to evaluate the investment risks of each country.Furthermore,cluster analysis is used to classify the countries into low,medium,and high-risk levels.Finally,policy recommendations are proposed based on the characteristics of countries with different risk levels,providing decision-making references for sporting goods manufacturing enterprises in selecting suitable countries for investment,enhancing risk prevention capabilities,and improving investment success rates.展开更多
The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the coun...The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.展开更多
The construction of human settlements plays a vital role in achieving sustainable development goals.With the growing population,both urban and rural planning—as well as the development of human settlements—on the Qi...The construction of human settlements plays a vital role in achieving sustainable development goals.With the growing population,both urban and rural planning—as well as the development of human settlements—on the Qinghai-Tibet Plateau in China have received increasing attention.This study proposed a comprehensive framework to assess the quality of human settlements and identify their limiting factors of Nyingchi City,southeastern Qinghai-Tibet Plateau of China.The framework integrated a region-specific evaluation system tailored to the plateau’s unique characteristics and utilized multi-source data collected through field-based questionnaires and remote sensing.Analytical methods employed include the Criteria Importance Through Intercriteria Correlation(CRITIC)weighting method,difference analysis for evaluating spatial and categorical variations,and a novel approach introduced in this study for identifying limiting factors.In August 2021,a questionnaire-based survey was conducted in the southeastern Qinghai-Tibet Plateau,yielding 823 valid responses.The average evaluation score for human settlement quality(HSQ)was(6.96±0.94),indicating that settlement conditions were approaching the satisfaction threshold.Notably,the score for the health dimension was(6.28±1.41),reflecting relatively underdeveloped health services in the region.From the perspective of spatial patterns,despite its favorable natural conditions,the HSQ in Medog County was relatively backward,reflecting uncoordinated development that warrants attention.Significant differences were observed in the perceptions of human settlements among different groups in terms of ethnicity,income,and educational background.Low ratings for income and employment conditions represented a major limitation to the local HSQ.The development of human settlements in the southeastern Qinghai-Tibet Plateau still needs further promotion due to population disparities and the challenges of creating a healthy environment in high-altitude regions.The results are valuable for improving human settlements in plateau regions,which can help make targeted policy recommendations.展开更多
Fatigue fracture is one of the most common failure modes of engineering compo-nents,and the combined action of geometrie discontinuity and multiaxial loading is more likely to cause severe fatigue damage of components...Fatigue fracture is one of the most common failure modes of engineering compo-nents,and the combined action of geometrie discontinuity and multiaxial loading is more likely to cause severe fatigue damage of components.This work focuses on the fatigue behavior of U-notched Q345 steel specimens with differen t notch sizes under proportional cyclic tension-torsion.Firstly,based on the concept of strain energy,the calculation method of critical plane is given and the equivalent stress of the specified path on the critical plane is extracted to char-acterize the equivalent stress distribution state and the stress gradient effect.Then,based on the high stress volume method and theory of critical distance,a simple method for determining the critical distance is given considering the contribution of stress at the dangerous point and the critical point.In addition,based on the idea of stress-distance normalization,a new stress gradient impact factor is defined and a new method for predicting the multiaxial fatigue life of notched specimens is given.The prediction results of the proposed model,the local stress-strain method and the point method of theory of critical distance are compared with the experimental results.The comparisons show that the prediction results of the proposed model are closer to experimentai life,and the calculation accuracy is higher.展开更多
The fatigue damage model based on theory of damage mechanics is capable of predicting the fatigue life under multiaxial loading.Meanwhile,the application of critical plane method in the prediction of multiaxial fatigu...The fatigue damage model based on theory of damage mechanics is capable of predicting the fatigue life under multiaxial loading.Meanwhile,the application of critical plane method in the prediction of multiaxial fatigue life has made certain progress.According to the law of thermodynamics,a new damage evolution equation is developed in the present study to predict the fatigue life of geometrically discontinuous structure under tension-torsion loading based on damage mechanics and the critical plane method.The essence of this approach is tha t the st rain parame ter of the uniaxial nonlinear fatigue damage model is replaced with the equivalent strain,which consists of the releva nt parame ters of the critical plane.However,it is difficult to calculate the stress-strain status and the critical plane position of geometrically dis?continuous structure by theoretical methods because of the existence of stress concentration and the multiaxial nonproportional characteristics.Therefore,a new numerical simulation method is proposed to determine the critical plane of geometrically discontinuous structure under multiaxial loading by means of the finite element method and MATLAB software.The fatigue life of notched specimens subjected to combined bending and torsion is predicted using the proposed met hod,and the result is compared with t hose from the experimen ts and the Manson-Cfiffin law.The comparisons show that the proposed method is superior to the Manson-Coffin law and is capable of reproducing the experimental results reasonably when the geometry of the structure is complex.It completely meets the needs of engineering practice.展开更多
According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculatio...According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably,展开更多
For its complexity, engineering construction schedule design is limited by various factors.Simulation-based engineering construction schedule takes critical path method (CPM) network as frame and calls complex cyclic ...For its complexity, engineering construction schedule design is limited by various factors.Simulation-based engineering construction schedule takes critical path method (CPM) network as frame and calls complex cyclic operation network (CYCLONE) simulation model enclosed in advance for its simulation nodes. CYCLONE simulation model takes charge of simulating stochastic duration of activity and efficiency of resources, while CPM model performs project scheduling. This combination avoids the shortcomings of both models. Furthermore, geographic information system (GIS) technique is utilized to visualize the construction processes which are otherwise difficult to be understood by static results described. Application in practical project verifies the feasibility and advantage of the technique.展开更多
Today, most construction projects in urban environments are complex high-rise buildings that present unique challenges, including local building ordinances and restrictions, adjoining public and residential areas, nar...Today, most construction projects in urban environments are complex high-rise buildings that present unique challenges, including local building ordinances and restrictions, adjoining public and residential areas, narrow sidewalks and streets, and underground utilities, all of which require extensive planning and tight schedules. A major problem facing such projects is to formulate realistic schedules that will make it possible to meet contractual completion dates with limited resources and budgets. The scheduling software products currently used in construction projects, which include Primavera P6, Microsoft Project, etc., are not actually applied as a scheduling tool in practical construction projects, which instead generally depend on Microsoft Excel or a bar-chart. This is because the existing scheduling programs cannot provide more user-oriented schedule format such as representing two-way multiple overlapping relationships. To overcome this deficiency, the BDM （beeline diagramming method） is proposed as a new networking technique in 2010. But two-way multiple overlapping relationships generate the loop in a conventional schedule computation process. This paper addresses the loop phenomenon of two-way multiple overlapping relationships in a BDM network as well as proposes the solutions of them, and then presents a practical application of two-way multiple overlapping relationships at a real project.展开更多
This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and succes...This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and success of quantitative decision-making approaches in project management through t</span><span style="font-family:Verdana;">he use of project evaluation review technique and the critical path method as regards project duration and critical activities of a project, were discussed. The review found that while both methods are effective in achieving success in project management, the relationship and connectivity of activities involved in a project life cycle are key aspects. The paper concludes that the project evaluation review technique is more effective when the duration of the project is uncertain, while the critical path method is effective when the project’s end time is certain. The paper, therefore, recommends that to achieve maximum operative efficiency in utilizing resources in project management, p</span><span style="font-family:Verdana;">rior to commencing the execution of a project, all required resources to cover every activity must be assembled and prioritized to eliminate interruptions that could bring delay and unnecessary cost implications. Again, policies focused on improving project execution should be implemented in developing nations to minimize the many cases of failed and delayed projects. Subsequently, stakeholders in projects must be given the right, under the law, to prosecute the government, its agencies and/or the executors of projects for failure to execute a project on schedule.</span>展开更多
The double-die ironing process is studied by means of UBM. The formulas of deformation load.contact stress on die surface, and tensile stress which acts on workpiece is obtained. Taking account of dirnensional accurac...The double-die ironing process is studied by means of UBM. The formulas of deformation load.contact stress on die surface, and tensile stress which acts on workpiece is obtained. Taking account of dirnensional accuracy, a new critical condition of limit reduction in cross section area is put forward for the flrst time. The test experiment indicats that results of theoretical analysis well accord with the actual conditions.[0]展开更多
We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopp...We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopping conduction formulation in conjunction with the incorporation of the random potential that has been shown to exist in insulator-conductor composites, it is demonstrated that the widely observed temperature dependence of granular hopping conduction emerges very naturally through the immediate-neighbor critical-path argument. Here, immediate-neighbor pairs are defined to be those where a line connecting two grains does not cross or by-pass other grains, and the critical-path argument denotes the derivation of sample conductance based on the geometric percolation condition that is marked by the critical conduction path in a random granular composite. Simulations based on the exact electrical network evaluation of finite-sample conductance show that the configuration- averaged results agree well with those obtained using the immediate-neighbor critical-path method. Furthermore, the results obtained using both these methods show good agreement with experimental data on hopping conduction in a sputtered metal-insulator composite Agx（SnO2）1-x, where x denotes the metal volume fraction. The present approach offers a relatively straightforward and simple expla- nation for the temperature behavior that has been widely observed over diverse material systems, but which has remained a puzzle in spite of the various efforts made to explain this phenomenon.展开更多
This paper shows that for DEM simulations of triaxial tests using samples with a grading that is repre- sentative of a real soil, the sample size significantly influences the observed material response. Four DEM sampl...This paper shows that for DEM simulations of triaxial tests using samples with a grading that is repre- sentative of a real soil, the sample size significantly influences the observed material response. Four DEM samples with identical initial states were produced： three cylindrical samples bounded by rigid wails and one bounded by a cubical periodic cell, When subjected to triaxial loading, the samples with rigid boundaries were more dilative, stiffer and reached a higher peak stress ratio than the sample enclosed by periodic boundaries. For the rigid-wall samples, dilatancy increased and stiffness decreased with increasing sample size, The periodic sample was effectively homogeneous, The void ratio increased and the contact density decreased close to the rigid walls, This heterogeneity reduced with increasing sample size. The positions of the critical state lines （CSLs） of the overall response in e-log p＇ space were sensitive to the sample size, although no difference was observed between their slopes. The critical states of the interior regions of the rigid-wall-bounded samples approached that of the homogeneous periodic sample with increasing sample size. The ultimate strength of the material at the critical state is independent of sample size.展开更多
The purpose of this paper is to use a very recent three critical points theorem due to Bonanno and Marano to establish the existence of at least three solutions for the quasilinear second order differential equation o...The purpose of this paper is to use a very recent three critical points theorem due to Bonanno and Marano to establish the existence of at least three solutions for the quasilinear second order differential equation on a compact interval[a,b] R{-u＇＇=（λf（x,u）＋g（u））h（u＇）,in（a,b）,u（a）=u（b）=0under ppropriate hypotheses.We exhibit the existence of at least three（weak）solutions and,and the results are illustrated by examples.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 51008167 and 51274126)the S&T Plan Project of Shandong Provincial Education Department (Grant No. J10LE07)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20103721120001)the Research Project Council of the Hong Kong SAR Government(Grant No. PolyU 513808)
文摘A new method for the determination of the critical slip surfaces of slopes is proposed in this paper. In this paper, the original critical slip field method is extended in terms of the total residual moment, values of residual work as well as the unbalanced thrust force at the exit point for a given non-circular slip surface. The most critical slip surface with the maximum representative value for a prescribed factor of safety will be optimized and located using the harmony search algorithm. The prescribed factor of safety is modified with certain tiny interval in order to find the critical slip surface where the maximum representative value is zero. The aforementioned approach to the location of the critical slip surface is greatly different from the traditional limit equilibrium procedure. Three typical soil slopes are evaluated by use of the proposed method, and the comparisons with the classical approaches have illustrated the applicability of the proposed method.
基金supported by the Thailand Research Fund(TRF)through the Royal Golden Jubilee Ph.D.Program(Grant No.PHD/0112/2553)the National Research University(NRU)initiative
文摘This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser＇s vertical distances, horizontal offsets, riser＇s weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR.
文摘In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory of genus, we obtain several results under different conditions.
文摘With the rapid development of economy and the intensification of market competition, project management involves various aspects of social development. The limitations of traditional project scheduling management methods are becoming more and more obvious. It is extremely urgent to create and apply new management technologies. According to the constraint theory, critical chain method is a method of controlling a project, which can greatly shorten the completion period of the project and reduce the cost of the enterprise. Firstly, the shortcomings of traditional project scheduling management methods are analyzed, and the importance of adopting key chain technology is pointed out. Secondly, the content of the basic chain method is summarized. Finally, the problems existing in the application of critical chain method are analyzed.
文摘Objective: to analyze the effect and value of intervention and guidance of nursing scoring method for children with critical diseases in child care. Methods: the samples were taken from 100 critically ill children admitted to our hospital from January 2020 to June 2021. According to the different nursing intervention methods, the patients were divided into the control group (routine nursing) and the research group (critical illness nursing score method intervention), with a single group of 50 cases. The data differences such as the incidence of complications, severity of illness, blood gas index and nursing satisfaction were observed and compared. Results: the total incidence rate of heart failure, potential respiratory failure, compensatory shock and irreversible organ failure in the study group was 6.00% significantly lower than that in the control group by 20.00% (P < 0.05). After the intervention, APACHE Ⅱ score and SOFA score of the two groups were lower than before the intervention, and the study group was significantly lower than the control group (P < 0.05). After the intervention, the oxygen partial pressure and carbon dioxide partial pressure of the two groups were better than before the intervention, and the research group was significantly better than the control group (p < 0.05). The satisfaction rate of the research group's family members to the nursing service was 96.00% higher than that of the control group's 84.00% (p < 0.05). Compared with the control group, the study group had higher scores in basic nursing, ward management, nursing safety and nursing documents (p < 0.05). Conclusion: the pediatric critical illness nursing score method has good intervention and guidance value for pediatric nursing, which not only can reduce the incidence of complications, but also can significantly improve the severity of the illness, blood gas indicators, and enhance the satisfaction of family members to the nursing service and the quality of nursing. It is worthy of clinical reference and promotion.
基金funded by the Chinese Academy of Sciences President's International Fellowship Initiative(2024VCC0009).
文摘Climate change and human activities have led to desertification and decreased land productivity,significantly affecting human livelihoods in desert regions.Identifying suitable areas for cultivating economic and native plants based on ecological capacity,biological restoration,and risk management can be valuable tools for combating desertification.In this study,we identified suitable areas for the growth of economic and medicinal Moringa peregrina trees in desert regions of Sistan and Baluchestan Province,southern Iran,using library research and field methods.We also assessed the economic involvement of local communities in areas under different topographic conditions(namely flat area,undulating area,rolling area,moderately sloping area,and steep area)in the study area.Financial indicators such as the net present value(NPV),benefit-cost ratio(BCR),internal rate of return(IRR),and return on investment(ROI)were calculated for areas under various topographic conditions in the study area.The rolling area with results of NPV(6142.75 USD),IRR(103.38),BCR(5.38),and ROI(in the 3rd year)was the best region for investing and cultivating M.peregrina.The minimum economic level varied from 0.80 hm2 in the flat area to 21.60 hm2 in the steep area.Also,approximately 5,314,629.51 hm2 of desert lands in the study area were deemed suitable for M.peregrina cultivation,benefiting around 1,743,246 households in the study area.Cultivating M.peregrina in southern Iran can positively affect local communities and help preserve land from erosion.Our study will provide theoretical support for planting native species in other degraded desert regions to enhance ecosystem services and the well-being of indigenous populations.
文摘With the continuous promotion of the Belt and Road initiative,the sporting goods manufacturing industry,as a key sector of Chinese enterprises’“going global”strategy,is actively expanding the markets of countries along the Belt and Road.However,there are significant differences in political,economic,and social environments among countries along the Belt and Road,which bring considerable uncertainties to the transnational investment of enterprises.Based on the investment environment of 70 countries along the Belt and Road,this paper constructs a risk evaluation index system including five dimensions:political and legal,economic and financial,socio-cultural,investment environment,and bilateral relations.The Criteria Importance Through Intercriteria Correlation(CRITIC)method is used to determine weight,Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method is employed to evaluate the investment risks of each country.Furthermore,cluster analysis is used to classify the countries into low,medium,and high-risk levels.Finally,policy recommendations are proposed based on the characteristics of countries with different risk levels,providing decision-making references for sporting goods manufacturing enterprises in selecting suitable countries for investment,enhancing risk prevention capabilities,and improving investment success rates.
基金The Fundamental Research Funds for the Central Universities,CHD,under contract No.300102264106the Shaanxi Natural Science Basic Research Program under contract No.2025JC-YBQN-370the Scientific and Technological Project of CNOOC Research Institute Co.,Ltd.under contract No.CCL2021RCPS0167KQN.
文摘The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.
基金Under the auspices of the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,No.2019QZKK0608)。
文摘The construction of human settlements plays a vital role in achieving sustainable development goals.With the growing population,both urban and rural planning—as well as the development of human settlements—on the Qinghai-Tibet Plateau in China have received increasing attention.This study proposed a comprehensive framework to assess the quality of human settlements and identify their limiting factors of Nyingchi City,southeastern Qinghai-Tibet Plateau of China.The framework integrated a region-specific evaluation system tailored to the plateau’s unique characteristics and utilized multi-source data collected through field-based questionnaires and remote sensing.Analytical methods employed include the Criteria Importance Through Intercriteria Correlation(CRITIC)weighting method,difference analysis for evaluating spatial and categorical variations,and a novel approach introduced in this study for identifying limiting factors.In August 2021,a questionnaire-based survey was conducted in the southeastern Qinghai-Tibet Plateau,yielding 823 valid responses.The average evaluation score for human settlement quality(HSQ)was(6.96±0.94),indicating that settlement conditions were approaching the satisfaction threshold.Notably,the score for the health dimension was(6.28±1.41),reflecting relatively underdeveloped health services in the region.From the perspective of spatial patterns,despite its favorable natural conditions,the HSQ in Medog County was relatively backward,reflecting uncoordinated development that warrants attention.Significant differences were observed in the perceptions of human settlements among different groups in terms of ethnicity,income,and educational background.Low ratings for income and employment conditions represented a major limitation to the local HSQ.The development of human settlements in the southeastern Qinghai-Tibet Plateau still needs further promotion due to population disparities and the challenges of creating a healthy environment in high-altitude regions.The results are valuable for improving human settlements in plateau regions,which can help make targeted policy recommendations.
基金This research was supported by the National Natural Science Foundation of China(Grant No.51605212)the Natural Science Foundation of Gansu Province(Grant No.20JR10RA161)the Project of Hongliu Excellent Youth Program of Lanzhou University of Technology(Grant No.2020062001).
文摘Fatigue fracture is one of the most common failure modes of engineering compo-nents,and the combined action of geometrie discontinuity and multiaxial loading is more likely to cause severe fatigue damage of components.This work focuses on the fatigue behavior of U-notched Q345 steel specimens with differen t notch sizes under proportional cyclic tension-torsion.Firstly,based on the concept of strain energy,the calculation method of critical plane is given and the equivalent stress of the specified path on the critical plane is extracted to char-acterize the equivalent stress distribution state and the stress gradient effect.Then,based on the high stress volume method and theory of critical distance,a simple method for determining the critical distance is given considering the contribution of stress at the dangerous point and the critical point.In addition,based on the idea of stress-distance normalization,a new stress gradient impact factor is defined and a new method for predicting the multiaxial fatigue life of notched specimens is given.The prediction results of the proposed model,the local stress-strain method and the point method of theory of critical distance are compared with the experimental results.The comparisons show that the prediction results of the proposed model are closer to experimentai life,and the calculation accuracy is higher.
基金the National Natural Science Foundation of China(Grant No.51605212)the Natural Science Foundation of Gansu Province(Grant No.17JR5RA122)the Project of Hongliu First-class Disciplines Development Program of Lanzhou University of Technology.
文摘The fatigue damage model based on theory of damage mechanics is capable of predicting the fatigue life under multiaxial loading.Meanwhile,the application of critical plane method in the prediction of multiaxial fatigue life has made certain progress.According to the law of thermodynamics,a new damage evolution equation is developed in the present study to predict the fatigue life of geometrically discontinuous structure under tension-torsion loading based on damage mechanics and the critical plane method.The essence of this approach is tha t the st rain parame ter of the uniaxial nonlinear fatigue damage model is replaced with the equivalent strain,which consists of the releva nt parame ters of the critical plane.However,it is difficult to calculate the stress-strain status and the critical plane position of geometrically dis?continuous structure by theoretical methods because of the existence of stress concentration and the multiaxial nonproportional characteristics.Therefore,a new numerical simulation method is proposed to determine the critical plane of geometrically discontinuous structure under multiaxial loading by means of the finite element method and MATLAB software.The fatigue life of notched specimens subjected to combined bending and torsion is predicted using the proposed met hod,and the result is compared with t hose from the experimen ts and the Manson-Cfiffin law.The comparisons show that the proposed method is superior to the Manson-Coffin law and is capable of reproducing the experimental results reasonably when the geometry of the structure is complex.It completely meets the needs of engineering practice.
基金supported by the National Science and Technology Plan of China (Major Project of the Eleventh Five-Year Plan, Grant No. 2006BAB04A13)the Philosophy and Social Science Fund of Education Department of Jiangsu Province (Grant No. 07SJD630006)+1 种基金the Third Key Discipline (Techno-Economics and Management) of the Project 211the Key Disciplines of Jiangsu Province (Engineering and Project Management)
文摘According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably,
基金Supported by National Natural Science Foundation of China( No. 50179023).
文摘For its complexity, engineering construction schedule design is limited by various factors.Simulation-based engineering construction schedule takes critical path method (CPM) network as frame and calls complex cyclic operation network (CYCLONE) simulation model enclosed in advance for its simulation nodes. CYCLONE simulation model takes charge of simulating stochastic duration of activity and efficiency of resources, while CPM model performs project scheduling. This combination avoids the shortcomings of both models. Furthermore, geographic information system (GIS) technique is utilized to visualize the construction processes which are otherwise difficult to be understood by static results described. Application in practical project verifies the feasibility and advantage of the technique.
文摘Today, most construction projects in urban environments are complex high-rise buildings that present unique challenges, including local building ordinances and restrictions, adjoining public and residential areas, narrow sidewalks and streets, and underground utilities, all of which require extensive planning and tight schedules. A major problem facing such projects is to formulate realistic schedules that will make it possible to meet contractual completion dates with limited resources and budgets. The scheduling software products currently used in construction projects, which include Primavera P6, Microsoft Project, etc., are not actually applied as a scheduling tool in practical construction projects, which instead generally depend on Microsoft Excel or a bar-chart. This is because the existing scheduling programs cannot provide more user-oriented schedule format such as representing two-way multiple overlapping relationships. To overcome this deficiency, the BDM （beeline diagramming method） is proposed as a new networking technique in 2010. But two-way multiple overlapping relationships generate the loop in a conventional schedule computation process. This paper addresses the loop phenomenon of two-way multiple overlapping relationships in a BDM network as well as proposes the solutions of them, and then presents a practical application of two-way multiple overlapping relationships at a real project.
文摘This paper reviewed the concepts of Project Evaluation Review Technique and<span style="font-family:Verdana;"> Critical Path Method in project management with practical examples. The methods and success of quantitative decision-making approaches in project management through t</span><span style="font-family:Verdana;">he use of project evaluation review technique and the critical path method as regards project duration and critical activities of a project, were discussed. The review found that while both methods are effective in achieving success in project management, the relationship and connectivity of activities involved in a project life cycle are key aspects. The paper concludes that the project evaluation review technique is more effective when the duration of the project is uncertain, while the critical path method is effective when the project’s end time is certain. The paper, therefore, recommends that to achieve maximum operative efficiency in utilizing resources in project management, p</span><span style="font-family:Verdana;">rior to commencing the execution of a project, all required resources to cover every activity must be assembled and prioritized to eliminate interruptions that could bring delay and unnecessary cost implications. Again, policies focused on improving project execution should be implemented in developing nations to minimize the many cases of failed and delayed projects. Subsequently, stakeholders in projects must be given the right, under the law, to prosecute the government, its agencies and/or the executors of projects for failure to execute a project on schedule.</span>
文摘The double-die ironing process is studied by means of UBM. The formulas of deformation load.contact stress on die surface, and tensile stress which acts on workpiece is obtained. Taking account of dirnensional accuracy, a new critical condition of limit reduction in cross section area is put forward for the flrst time. The test experiment indicats that results of theoretical analysis well accord with the actual conditions.[0]
文摘We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopping conduction formulation in conjunction with the incorporation of the random potential that has been shown to exist in insulator-conductor composites, it is demonstrated that the widely observed temperature dependence of granular hopping conduction emerges very naturally through the immediate-neighbor critical-path argument. Here, immediate-neighbor pairs are defined to be those where a line connecting two grains does not cross or by-pass other grains, and the critical-path argument denotes the derivation of sample conductance based on the geometric percolation condition that is marked by the critical conduction path in a random granular composite. Simulations based on the exact electrical network evaluation of finite-sample conductance show that the configuration- averaged results agree well with those obtained using the immediate-neighbor critical-path method. Furthermore, the results obtained using both these methods show good agreement with experimental data on hopping conduction in a sputtered metal-insulator composite Agx（SnO2）1-x, where x denotes the metal volume fraction. The present approach offers a relatively straightforward and simple expla- nation for the temperature behavior that has been widely observed over diverse material systems, but which has remained a puzzle in spite of the various efforts made to explain this phenomenon.
基金funding from the Royal Commission for the Exhibition of 1851provided as part of grant EP/1006761/1 from the Engineering and Physical Sciences Research Council
文摘This paper shows that for DEM simulations of triaxial tests using samples with a grading that is repre- sentative of a real soil, the sample size significantly influences the observed material response. Four DEM samples with identical initial states were produced： three cylindrical samples bounded by rigid wails and one bounded by a cubical periodic cell, When subjected to triaxial loading, the samples with rigid boundaries were more dilative, stiffer and reached a higher peak stress ratio than the sample enclosed by periodic boundaries. For the rigid-wall samples, dilatancy increased and stiffness decreased with increasing sample size, The periodic sample was effectively homogeneous, The void ratio increased and the contact density decreased close to the rigid walls, This heterogeneity reduced with increasing sample size. The positions of the critical state lines （CSLs） of the overall response in e-log p＇ space were sensitive to the sample size, although no difference was observed between their slopes. The critical states of the interior regions of the rigid-wall-bounded samples approached that of the homogeneous periodic sample with increasing sample size. The ultimate strength of the material at the critical state is independent of sample size.
基金supported in part by grant from IPM(No.89350020)
文摘The purpose of this paper is to use a very recent three critical points theorem due to Bonanno and Marano to establish the existence of at least three solutions for the quasilinear second order differential equation on a compact interval[a,b] R{-u＇＇=（λf（x,u）＋g（u））h（u＇）,in（a,b）,u（a）=u（b）=0under ppropriate hypotheses.We exhibit the existence of at least three（weak）solutions and,and the results are illustrated by examples.
