Deployment of nodes based on K-barrier coverage in an underground wireless sensor network is described. The network has automatic routing recovery by using a basic information table (BIT) for each node. An RSSI positi...Deployment of nodes based on K-barrier coverage in an underground wireless sensor network is described. The network has automatic routing recovery by using a basic information table (BIT) for each node. An RSSI positioning algorithm based on a path loss model in the coal mine is used to calculate the path loss in real time within the actual lane way environment. Simulation results show that the packet loss can be controlled to less than 15% by the routing recovery algorithm under special recovery circum- stances. The location precision is within 5 m, which greatly enhances performance compared to tradi- tional frequency location systems. This approach can meet the needs for accurate location underground.展开更多
To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated....To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated. Guidance commands are generated based on optimal guidance law. SDRE control method employs factorization of the nonlinear dynamics into a state vector and state dependent matrix valued function. State-dependent coefficients are derived based on reentry motion equations in pitch and yaw channels. Unlike constant weighting matrix Q, elements of Q are set as the functions of state error so as to get satisfactory feedback and eliminate state error rapidly, then formulation of SDRE is realized. Riccati equation is solved real-timely with Schur algorithm. State feedback control law u(x) is derived with linear quadratic regulator (LQR) method. Simulation results show that SDRE controller steadily tracks attitude command, and impact point error of reentry vehicle is acceptable. Compared with PID controller, tracking performance of attitude command using SDRE controller is better with smaller control surface deflection. The attitude tracking error with SDRE controller is within 5°, and the control deflection is within 30°.展开更多
One promising joining method for NiTi-SMA (shape memory alloy)-components is laser welding. This joining technology bears huge potential regarding process automation and mechanical properties as well as durability, ...One promising joining method for NiTi-SMA (shape memory alloy)-components is laser welding. This joining technology bears huge potential regarding process automation and mechanical properties as well as durability, especially within the field of small- and medium-sized actuators. However, there is still need for research due to unsolved issues influencing the microstructure and thus effecting mechanical properties as well as SMA-characteristics of these joints. Therefore, the purpose of this paper is the evaluation of quality parameters of NiTi-NiTi-wire-joints. For this purpose, design of experiments with a fractional factorial design is used for the investigation, because of its high potential to decrease experimental effort. This paper provides a basis for future research in the field of SMA-actuators and joining.展开更多
Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the funct...Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the functional connectivity(rainfall-runoff processes at morphological unit scale). In this paper the sediment connectivity approach was applied at basin scale both using Sediment Delivery Distributed(SEDD) model, which takes into account the hillslope sediment transport, and sediment yield measurements carried out at SPA2 experimental basin(Sicily, Italy). The expression of the sediment delivery ratio SDRi of a morphological unit was modified for highlighting two components corresponding to the structural(SDR_(L,i)) and functional(SDR_(F,i)) sediment connectivity, respectively. For SPA2 basin the frequency distribution of the travel time of each morphological unit was used to estimate the coefficient βL of the structural component of the sediment delivery ratio of each morphological unit. Then, using the sediment yield measurements carried out at the outlet of the experimental SPA2 basin in the period April 2000-March 2015, the SEDD model was calibrated at event scale for estimating the coefficient βF of the functional component of the sediment delivery ratio. At event scale the developed analysis stated that the functional connectivity is dependent on the magnitude of erosion events. Intermediate and high events, which were characterized by the lowest values of the functional coefficient, determine a more high functional connectivity and are characterized by a more efficient sediment transport along the hillslopes. Finally, at annual scale, the model was calibrated for the period 2000-2015 and relationships for estimating the coefficient βF,a of the functional component of the sediment delivery ratio taking into account the intensity of erosion events occurring in each year were determined. At annual scale, the analysis demonstrated that the functional coefficient was always greater than the landscape coefficient and the sediment connectivity was always controlled by the low values of the functional component.展开更多
The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is...The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.展开更多
Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size...Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size. Factors impacting bicycle use in medium sized cities (urban planning, other transport means, adequacy of installations and parking spaces, etc.) have been examined. Bicycle can be something more than a sport or entertainment activity and has the potential to become an efficient means of transport. Xanthi is a medium sized town in Northern Greece. Its total area is 153 km2 and 65,000 people live there. An analysis of the existing traffic schemes in the city has pointed out the necessity of an organized bicycle paths network both cost effective and time saving. The main characteristics of such a network are described, hoping that in its completed form could impose the features of sustainable mobility and would be a paradigm for mid-sized cities in the country. Cars could be kept out of the central part of Xanthi ifa bicycle paths network is built using a ring-like scheme, since the residents favor the use of bicycle. Local authorities' plans must encourage the lending of public owned bicycles.展开更多
RFID has the advantages of waterproof, antimagnetic, heat resistance, long service life, great reading distance, encrypting data on label, greater capacity of storing data and free modification on stored information c...RFID has the advantages of waterproof, antimagnetic, heat resistance, long service life, great reading distance, encrypting data on label, greater capacity of storing data and free modification on stored information compared with bar code. Applying it brings revolutionary change to the retail and logistics industry. Selecting technology to manage RFID and selecting strategy to coordinate RFID is very important to promote the application of RFID. The paper implements RFtD management system, ALE engine and data processing components, and expounds the technique and details implementing the system.展开更多
This paper focuses on the economic development and urban morphology as well as its impact on the transportation system during the urban expansion of Shanghai in the last more than 20 years(1986-2008).Based on data fro...This paper focuses on the economic development and urban morphology as well as its impact on the transportation system during the urban expansion of Shanghai in the last more than 20 years(1986-2008).Based on data from 3 comprehensive transport surveys of Shanghai since 1986,the changes in residential trip demand,vehicle use,and the spatial distribution of trips were studied to understand the demands on the transportation system.The factors contributing to those changes in transportation demand were discussed,by which the conclusions were arrived:1) economic development promotes population growth and stimulates residential trip demand greatly;2) unsynchronized migration of population and job from central district to periphery district of Shanghai make trips and congestion diffuse in the same way;and 3) urban sprawl from a city center encourages the single-occupant vehicle mode,which imposes greater pressure on the roadway system.It is concluded that urban development should coordinate with the transportation system planning and expansion.展开更多
Background: Lower body positive pressure (LBPP) treadmills can be used in rehabilitation programs and/or to supplement tun mileage in healthy runners by reducing the effective body weight and impact associated with...Background: Lower body positive pressure (LBPP) treadmills can be used in rehabilitation programs and/or to supplement tun mileage in healthy runners by reducing the effective body weight and impact associated with running. The purpose of this study is to determine if body weight support influences the stride length (SL)-velocity as well as leg impact acceleration relationship during running. Methods: Subjects (n = 10, 21.4 ± 2.0 years, 72.4 ± 10.3 kg, 1.76 ± 0.09 m) completed 16 run conditions consisting of specific body weight support and velocity combinations. Velocities tested were 100%, 110%, 120%, and 130% of the preferred velocity (2.75± 0.36 m/s). Body weight support conditions consisted of 0, 60%,5, 70%, and 80% body weight support. SL and leg impact accelerations were determined using a light-weight accelerometer mounted on the surface of the anterior-distal aspect of the tibia. A 4 × 4 (velocity x body weight support) repeated measures ANOVA was used for each dependent variable (a = 0.05). Results: Neither SL nor leg impact acceleration were influenced by the interaction of body weight support and velocity (p 〉 0.05). SL was least during no body weight support (p 〈 0.05) but not different between 60%, 70%, and 80% support (p 〉 0.05). Leg impact acceleration was greatest during no body weight support (p 〈 0.05) but not different between 60%, 70%, and 80% support (p 〉 0.05). SL and leg impact accelerations increased with velocity regardless of support (p 〈 0.05). Conclusion: The relationships between SL and leg impact accelerations with velocity were not influenced by body weight support.展开更多
A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated durin...A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated during the study.The experimental results show that for aperture diameters of 0.4,0.6,or 0.8 mm smaller apertures provide more complete filtration.Rotations of 12,20,28,or 40 r/min show that higher speeds give more efficient filtration.Suspended solids decreased in both particle size and concentration after the filtration.The separated slime can be directly reused as a fuel.Efficient filtration pretreatment systems for coal mine drainage were investigated and the economic feasibility is analyzed in this article.展开更多
Mercury is highly toxic heavy metal pollution attracted the attention of the world. This paper analyzes the situation the main industry in mercury use PVC production. Manufacture of battery, electric light, medical eq...Mercury is highly toxic heavy metal pollution attracted the attention of the world. This paper analyzes the situation the main industry in mercury use PVC production. Manufacture of battery, electric light, medical equipment in China. Furthermore, it discusses the details of the best technology the use of mercury emissions reduction and mercury control in that industry. The result is that certain technologies such as low mercury. In PVC industry catalyst, as mercury battery, amalgam substituted Mercury and LED light in the electric light source industry. electronics the thermometer and blood pressure in the medical device industry and so on, reduce mercury able to make full use of and emission reduction in risk mercury pollution to the environment.展开更多
The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated b...The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria (WIN). And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.展开更多
The paper deals with miniature actuators and scaling effect, which occurs in using of these actuators. Scaling effect describes how much decreased performance in miniaturized actuator is. Scaling effect law helps to m...The paper deals with miniature actuators and scaling effect, which occurs in using of these actuators. Scaling effect describes how much decreased performance in miniaturized actuator is. Scaling effect law helps to make perfect decision for right type of actuator. This analysis should be as the first strategic step for actuator selection. Research in area of in-pipe machine shows that scaling effect in both used actuator types (electromagnetic and piezoelectric) is the same. Passive forces cannot be neglected, because of their values, which are comparable with active forces in system. There is a potential risk, that designed system will have bigger passive forces than active forces and system cannot fulfill requirements. Energy sources selection has also important role in system design with respecting the energy requirements of selected actuator. Consequently, energy balance is also important viewpoint for actuator selection.展开更多
ADVN (2,2'-Azobis (2,4-dimethyl) valeronitrile), a free radical initiator, is widely applied for the polymerization reaction of polymers in the chemical industries. When ADVN releases free radical during the deco...ADVN (2,2'-Azobis (2,4-dimethyl) valeronitrile), a free radical initiator, is widely applied for the polymerization reaction of polymers in the chemical industries. When ADVN releases free radical during the decomposition process, it can accompany abundant heat and huge pressure to increase the possibility of thermal runaway and hazard, causing unacceptable thermal explosion or fire accidents. To develop an inherently safer process for ADVN, the thermal stability parameters of ADVN were obtained to investigate thermal decomposition characteristics using a DSC (differential scanning calorimetry) and TG (thermogravimetry). We used various kinetic models to completely depict the kinetic behavior and determine the thermal safety parameters for ADVN. The green thermal analysis approach could be used to substitute for complicated procedures and large-scale experiments of traditional thermal analysis methods, avoiding environmental pollution and energy depletion.展开更多
In power systems, a large number of OPLs (overhead power lines) are more than 40 years old and some even exceed 50 years old. The key issue for power systems managers, public utilities companies and electrical engin...In power systems, a large number of OPLs (overhead power lines) are more than 40 years old and some even exceed 50 years old. The key issue for power systems managers, public utilities companies and electrical engineers today concerns the manner in which available financial resources should be invested in these OPLs to provide the greatest impact on the power system as a whole and to address the OPLs that require urgent revitalization. This paper presents the application of the software tool RevOPL, developed using Microsoft Access utilizing the "methodology for revitalization of high-voltage OPLs". The aim is to present both the methodology and software to objectively evaluate the condition of an OPL and determine its remaining service life. The application of this software tool provides a proposal for the scheduling and scope of planned revitalization activities, which are obtained through the optimization of the technical characteristics while remaining within the available budget.展开更多
Sanming model in healthcare reform has attracted much attention due to its comprehensive and efficient exploration,while its impact on physicians’prescribing behavior remains unknown.In the present study,we aimed to ...Sanming model in healthcare reform has attracted much attention due to its comprehensive and efficient exploration,while its impact on physicians’prescribing behavior remains unknown.In the present study,we aimed to evaluate the impact of Sanming reform on physicians’medicine use in county-level public hospitals.We collected outpatient prescriptions in the internal medicine and pediatric departments from nine county public hospitals in Sanming from January 2011 to December 2017.We used six prescribing indicators to analyze physicians’medicine use.The Mann-Kendall test was used to examine trends in the study outcomes.A total of 1577904 outpatient prescriptions were included in this study.The average prescription rate of antibiotics and combined antibiotics were 57.5%and 12.2%in 2011,respectively,which were declined to 28.2%(P=0.007)and 2.9%(P=0.003)in 2017,respectively.The average prescription rate of injection was 30.2%in 2011 and declined to 5.3%(P=0.003)in 2017.As for the subgroup analysis of the internal medicine and pediatric departments,the average prescription rate of antibiotics was 39.3%and 71.4%in 2011,respectively,which was declined to 10.2%(P=0.003)and 47.3%(P=0.035)in 2017,respectively.The average prescription rate of combined antibiotics was 15.9%and 9.4%in 2011,respectively,which was declined to 2.9%(P=0.003)and 2.9%(P=0.016),respectively.The average prescription rate of injection was 17.8%and 39.6%in 2011,respectively,which was declined to 1.9%(P=0.003)and 9.0%(P=0.003),respectively.Our study showed a significant decreasing trend in antibiotic use in county-level public hospitals after the Sanming healthcare reform,indicating that the reform successfully promoted the appropriate use of medicine to some extent.展开更多
In this paper,we apply the material point method(MPM),also known as a meshfree method,to examine the crush behaviour of thin tubular columns.Unlike the finite element method,randomly-distributed-weak-particle triggers...In this paper,we apply the material point method(MPM),also known as a meshfree method,to examine the crush behaviour of thin tubular columns.Unlike the finite element method,randomly-distributed-weak-particle triggers were used to account for the deformation behaviour of collapse modes.Both symmetric and asymmetric modes of deformation and their associated mean collapse loads are determined for an elasto-plastic constitutive law describing the tubular columns.Attention was devoted to the accuracy and the convergence of the MPM simulation,which is determined by the number of the particles and the size of the background cells used in our explicit solver.Furthermore,a novel contact approach was adopted to establish the crush behaviour of the tubular columns.Two aspects of the work were accordingly examined,including three different crush velocities(5,10 and 15 m/s) and varied geometrical features of the tube(t/d and l/d) based on the deformation history.The results of our model,which were compared with existing analytical predictions and experimental findings,identify the critical geometric features of the tubular columns that would dictate the deformation mode as being either progressive collapse or following Euler's buckling mode.展开更多
基金supported by the National Key Technology R&D Program of China (No. 2008BAH37B05095)
文摘Deployment of nodes based on K-barrier coverage in an underground wireless sensor network is described. The network has automatic routing recovery by using a basic information table (BIT) for each node. An RSSI positioning algorithm based on a path loss model in the coal mine is used to calculate the path loss in real time within the actual lane way environment. Simulation results show that the packet loss can be controlled to less than 15% by the routing recovery algorithm under special recovery circum- stances. The location precision is within 5 m, which greatly enhances performance compared to tradi- tional frequency location systems. This approach can meet the needs for accurate location underground.
基金Project(51105287)supported by the National Natural Science Foundation of China
文摘To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated. Guidance commands are generated based on optimal guidance law. SDRE control method employs factorization of the nonlinear dynamics into a state vector and state dependent matrix valued function. State-dependent coefficients are derived based on reentry motion equations in pitch and yaw channels. Unlike constant weighting matrix Q, elements of Q are set as the functions of state error so as to get satisfactory feedback and eliminate state error rapidly, then formulation of SDRE is realized. Riccati equation is solved real-timely with Schur algorithm. State feedback control law u(x) is derived with linear quadratic regulator (LQR) method. Simulation results show that SDRE controller steadily tracks attitude command, and impact point error of reentry vehicle is acceptable. Compared with PID controller, tracking performance of attitude command using SDRE controller is better with smaller control surface deflection. The attitude tracking error with SDRE controller is within 5°, and the control deflection is within 30°.
文摘One promising joining method for NiTi-SMA (shape memory alloy)-components is laser welding. This joining technology bears huge potential regarding process automation and mechanical properties as well as durability, especially within the field of small- and medium-sized actuators. However, there is still need for research due to unsolved issues influencing the microstructure and thus effecting mechanical properties as well as SMA-characteristics of these joints. Therefore, the purpose of this paper is the evaluation of quality parameters of NiTi-NiTi-wire-joints. For this purpose, design of experiments with a fractional factorial design is used for the investigation, because of its high potential to decrease experimental effort. This paper provides a basis for future research in the field of SMA-actuators and joining.
文摘Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity(morphological unit, slope length, slope steepness, travel time) of a basin and to the functional connectivity(rainfall-runoff processes at morphological unit scale). In this paper the sediment connectivity approach was applied at basin scale both using Sediment Delivery Distributed(SEDD) model, which takes into account the hillslope sediment transport, and sediment yield measurements carried out at SPA2 experimental basin(Sicily, Italy). The expression of the sediment delivery ratio SDRi of a morphological unit was modified for highlighting two components corresponding to the structural(SDR_(L,i)) and functional(SDR_(F,i)) sediment connectivity, respectively. For SPA2 basin the frequency distribution of the travel time of each morphological unit was used to estimate the coefficient βL of the structural component of the sediment delivery ratio of each morphological unit. Then, using the sediment yield measurements carried out at the outlet of the experimental SPA2 basin in the period April 2000-March 2015, the SEDD model was calibrated at event scale for estimating the coefficient βF of the functional component of the sediment delivery ratio. At event scale the developed analysis stated that the functional connectivity is dependent on the magnitude of erosion events. Intermediate and high events, which were characterized by the lowest values of the functional coefficient, determine a more high functional connectivity and are characterized by a more efficient sediment transport along the hillslopes. Finally, at annual scale, the model was calibrated for the period 2000-2015 and relationships for estimating the coefficient βF,a of the functional component of the sediment delivery ratio taking into account the intensity of erosion events occurring in each year were determined. At annual scale, the analysis demonstrated that the functional coefficient was always greater than the landscape coefficient and the sediment connectivity was always controlled by the low values of the functional component.
基金Project(2012BAJ06B04)supported by"12th Five-Year Plan"National science and Technology,ChinaProject(2014-228)supported by Department of Housing and Urban Rural Development of Hebei,China
文摘The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.
文摘Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size. Factors impacting bicycle use in medium sized cities (urban planning, other transport means, adequacy of installations and parking spaces, etc.) have been examined. Bicycle can be something more than a sport or entertainment activity and has the potential to become an efficient means of transport. Xanthi is a medium sized town in Northern Greece. Its total area is 153 km2 and 65,000 people live there. An analysis of the existing traffic schemes in the city has pointed out the necessity of an organized bicycle paths network both cost effective and time saving. The main characteristics of such a network are described, hoping that in its completed form could impose the features of sustainable mobility and would be a paradigm for mid-sized cities in the country. Cars could be kept out of the central part of Xanthi ifa bicycle paths network is built using a ring-like scheme, since the residents favor the use of bicycle. Local authorities' plans must encourage the lending of public owned bicycles.
文摘RFID has the advantages of waterproof, antimagnetic, heat resistance, long service life, great reading distance, encrypting data on label, greater capacity of storing data and free modification on stored information compared with bar code. Applying it brings revolutionary change to the retail and logistics industry. Selecting technology to manage RFID and selecting strategy to coordinate RFID is very important to promote the application of RFID. The paper implements RFtD management system, ALE engine and data processing components, and expounds the technique and details implementing the system.
基金Under the auspices of National Natural Science Foundation of China (No 70803034)
文摘This paper focuses on the economic development and urban morphology as well as its impact on the transportation system during the urban expansion of Shanghai in the last more than 20 years(1986-2008).Based on data from 3 comprehensive transport surveys of Shanghai since 1986,the changes in residential trip demand,vehicle use,and the spatial distribution of trips were studied to understand the demands on the transportation system.The factors contributing to those changes in transportation demand were discussed,by which the conclusions were arrived:1) economic development promotes population growth and stimulates residential trip demand greatly;2) unsynchronized migration of population and job from central district to periphery district of Shanghai make trips and congestion diffuse in the same way;and 3) urban sprawl from a city center encourages the single-occupant vehicle mode,which imposes greater pressure on the roadway system.It is concluded that urban development should coordinate with the transportation system planning and expansion.
文摘Background: Lower body positive pressure (LBPP) treadmills can be used in rehabilitation programs and/or to supplement tun mileage in healthy runners by reducing the effective body weight and impact associated with running. The purpose of this study is to determine if body weight support influences the stride length (SL)-velocity as well as leg impact acceleration relationship during running. Methods: Subjects (n = 10, 21.4 ± 2.0 years, 72.4 ± 10.3 kg, 1.76 ± 0.09 m) completed 16 run conditions consisting of specific body weight support and velocity combinations. Velocities tested were 100%, 110%, 120%, and 130% of the preferred velocity (2.75± 0.36 m/s). Body weight support conditions consisted of 0, 60%,5, 70%, and 80% body weight support. SL and leg impact accelerations were determined using a light-weight accelerometer mounted on the surface of the anterior-distal aspect of the tibia. A 4 × 4 (velocity x body weight support) repeated measures ANOVA was used for each dependent variable (a = 0.05). Results: Neither SL nor leg impact acceleration were influenced by the interaction of body weight support and velocity (p 〉 0.05). SL was least during no body weight support (p 〈 0.05) but not different between 60%, 70%, and 80% support (p 〉 0.05). Leg impact acceleration was greatest during no body weight support (p 〈 0.05) but not different between 60%, 70%, and 80% support (p 〉 0.05). SL and leg impact accelerations increased with velocity regardless of support (p 〈 0.05). Conclusion: The relationships between SL and leg impact accelerations with velocity were not influenced by body weight support.
基金support through Special Basic Research Fund of China Central University(No.2011QH01)Innovative Experiment Projects for Undergraduates
文摘A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated during the study.The experimental results show that for aperture diameters of 0.4,0.6,or 0.8 mm smaller apertures provide more complete filtration.Rotations of 12,20,28,or 40 r/min show that higher speeds give more efficient filtration.Suspended solids decreased in both particle size and concentration after the filtration.The separated slime can be directly reused as a fuel.Efficient filtration pretreatment systems for coal mine drainage were investigated and the economic feasibility is analyzed in this article.
文摘Mercury is highly toxic heavy metal pollution attracted the attention of the world. This paper analyzes the situation the main industry in mercury use PVC production. Manufacture of battery, electric light, medical equipment in China. Furthermore, it discusses the details of the best technology the use of mercury emissions reduction and mercury control in that industry. The result is that certain technologies such as low mercury. In PVC industry catalyst, as mercury battery, amalgam substituted Mercury and LED light in the electric light source industry. electronics the thermometer and blood pressure in the medical device industry and so on, reduce mercury able to make full use of and emission reduction in risk mercury pollution to the environment.
文摘The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria (WIN). And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.
文摘The paper deals with miniature actuators and scaling effect, which occurs in using of these actuators. Scaling effect describes how much decreased performance in miniaturized actuator is. Scaling effect law helps to make perfect decision for right type of actuator. This analysis should be as the first strategic step for actuator selection. Research in area of in-pipe machine shows that scaling effect in both used actuator types (electromagnetic and piezoelectric) is the same. Passive forces cannot be neglected, because of their values, which are comparable with active forces in system. There is a potential risk, that designed system will have bigger passive forces than active forces and system cannot fulfill requirements. Energy sources selection has also important role in system design with respecting the energy requirements of selected actuator. Consequently, energy balance is also important viewpoint for actuator selection.
文摘ADVN (2,2'-Azobis (2,4-dimethyl) valeronitrile), a free radical initiator, is widely applied for the polymerization reaction of polymers in the chemical industries. When ADVN releases free radical during the decomposition process, it can accompany abundant heat and huge pressure to increase the possibility of thermal runaway and hazard, causing unacceptable thermal explosion or fire accidents. To develop an inherently safer process for ADVN, the thermal stability parameters of ADVN were obtained to investigate thermal decomposition characteristics using a DSC (differential scanning calorimetry) and TG (thermogravimetry). We used various kinetic models to completely depict the kinetic behavior and determine the thermal safety parameters for ADVN. The green thermal analysis approach could be used to substitute for complicated procedures and large-scale experiments of traditional thermal analysis methods, avoiding environmental pollution and energy depletion.
文摘In power systems, a large number of OPLs (overhead power lines) are more than 40 years old and some even exceed 50 years old. The key issue for power systems managers, public utilities companies and electrical engineers today concerns the manner in which available financial resources should be invested in these OPLs to provide the greatest impact on the power system as a whole and to address the OPLs that require urgent revitalization. This paper presents the application of the software tool RevOPL, developed using Microsoft Access utilizing the "methodology for revitalization of high-voltage OPLs". The aim is to present both the methodology and software to objectively evaluate the condition of an OPL and determine its remaining service life. The application of this software tool provides a proposal for the scheduling and scope of planned revitalization activities, which are obtained through the optimization of the technical characteristics while remaining within the available budget.
基金the Health and Family Planning Commission of Sanming for their support and cooperation
文摘Sanming model in healthcare reform has attracted much attention due to its comprehensive and efficient exploration,while its impact on physicians’prescribing behavior remains unknown.In the present study,we aimed to evaluate the impact of Sanming reform on physicians’medicine use in county-level public hospitals.We collected outpatient prescriptions in the internal medicine and pediatric departments from nine county public hospitals in Sanming from January 2011 to December 2017.We used six prescribing indicators to analyze physicians’medicine use.The Mann-Kendall test was used to examine trends in the study outcomes.A total of 1577904 outpatient prescriptions were included in this study.The average prescription rate of antibiotics and combined antibiotics were 57.5%and 12.2%in 2011,respectively,which were declined to 28.2%(P=0.007)and 2.9%(P=0.003)in 2017,respectively.The average prescription rate of injection was 30.2%in 2011 and declined to 5.3%(P=0.003)in 2017.As for the subgroup analysis of the internal medicine and pediatric departments,the average prescription rate of antibiotics was 39.3%and 71.4%in 2011,respectively,which was declined to 10.2%(P=0.003)and 47.3%(P=0.035)in 2017,respectively.The average prescription rate of combined antibiotics was 15.9%and 9.4%in 2011,respectively,which was declined to 2.9%(P=0.003)and 2.9%(P=0.016),respectively.The average prescription rate of injection was 17.8%and 39.6%in 2011,respectively,which was declined to 1.9%(P=0.003)and 9.0%(P=0.003),respectively.Our study showed a significant decreasing trend in antibiotic use in county-level public hospitals after the Sanming healthcare reform,indicating that the reform successfully promoted the appropriate use of medicine to some extent.
基金supported by the National Basic Research Program of China (Grant No. 2010CB832701)Natural Sciences and Engineering Research Council of Canada (NSERC)
文摘In this paper,we apply the material point method(MPM),also known as a meshfree method,to examine the crush behaviour of thin tubular columns.Unlike the finite element method,randomly-distributed-weak-particle triggers were used to account for the deformation behaviour of collapse modes.Both symmetric and asymmetric modes of deformation and their associated mean collapse loads are determined for an elasto-plastic constitutive law describing the tubular columns.Attention was devoted to the accuracy and the convergence of the MPM simulation,which is determined by the number of the particles and the size of the background cells used in our explicit solver.Furthermore,a novel contact approach was adopted to establish the crush behaviour of the tubular columns.Two aspects of the work were accordingly examined,including three different crush velocities(5,10 and 15 m/s) and varied geometrical features of the tube(t/d and l/d) based on the deformation history.The results of our model,which were compared with existing analytical predictions and experimental findings,identify the critical geometric features of the tubular columns that would dictate the deformation mode as being either progressive collapse or following Euler's buckling mode.