This study investigates relationships between congestion and travel time performance metrics and crashes on road segments. The study focuses on work zone routes in Iowa, utilizing 2021 commercially-available probe veh...This study investigates relationships between congestion and travel time performance metrics and crashes on road segments. The study focuses on work zone routes in Iowa, utilizing 2021 commercially-available probe vehicle data and crash data. Travel time performance metrics were derived from the probe vehicle data, and crash counts were obtained from the crash data. Additional variables included road characteristics (traffic volume, road type, segment length) and a categorical variable for the presence of a work zone. A mixed effect linear regression model was employed to identify relationships between road segment crash counts and the selected performance metrics. This was accomplished for two sets of models that include congestion performance measures at different defining threshold values, along with travel time performance measures. The study results indicate that the congestion indicators, certain travel time performance measures, and traffic counts were statistically significant and positively correlated with crash counts. Indicator variables for rural interstate locations and non-active work zones have a stronger influence on crash count than those for municipal interstate locations and active work zones. These findings can inform decision-makers on work zone safety strategies and crash mitigation planning, especially in high traffic volume areas prone to congestion and queues.展开更多
The Neoarchaean Kaigoorlie Gold Field contains the giant Golden Mile and world-class Mt Charlotte deposits,which have been the subject of much research for over 100 years.The Golden Mile deposit is a complex array of ...The Neoarchaean Kaigoorlie Gold Field contains the giant Golden Mile and world-class Mt Charlotte deposits,which have been the subject of much research for over 100 years.The Golden Mile deposit is a complex array of ductile to brittle vein and breccia lodes that are predominantly hosted in the highlyfractionated Golden Mile Dolerite sill.The Fimiston lodes comprise an array of narrow lodes that evolved broadly syn- to late-formation of the regional D2 NW-trending foliation.The lodes are characterized by pyrite veinlets and disseminations,quartz veinlets and breccias,and banded quartz-carbonate veins with sericite,carbonate,and pyrite-dominated alteration.Bonanza Green-Leader,or Oroya-style,lodes,with grades in excess of 1000 g/t Au,are similar to the Fimiston-style lodes,but are characterized by abundant visible gold,native tellurium and more abundant telluride minerals within roscoelitebearing alteration zones.The arguably structurally younger Mt Charlotte-style lodes are characterized by a pipe-shaped,coarse-grained quartz,carbonate and scheelite vein-stockwork with distinct verticallyzoned,carbonate-sericite-albite-pyrite ± pyrrhotite dominant alteration assemblages around veins within Unit 8 of the Golden Mile dolerite and porphyry dykes.The network of steep- and gently-dipping extension and shear fracture-fill veins are associated with NE-trending fault se ts that cross cut the regional NW-trend.The deposit area is intruded by swarms of porphyry dykes,including syn-volcanic mafic dykes,early and volumetrically most significant c.2.67 Ga feldspar-phyric porphyry dykes,as well as later c.2.66-2.65 Ga calc-alkaline hornblende-phyric dykes associated with younger c.2.65-2.64 Ga lamprophyre dykes.All post-volcanic dykes have similar orientations to the Fimiston lodes.The feldspar dykes are clearly overprinted by all styles of mineralization,although the relationship between hornblende-phyric and lamprophyre dykes and gold mineralization is more ambiguous.Most agree that gold mineralization was post-peak regiona展开更多
There are costs for doing the right thing,but regret is not one of those costs.I learned this lesson the hard way throughout a 42-year engineering career.As a young engineer,raising a family,I was more adaptable to ma...There are costs for doing the right thing,but regret is not one of those costs.I learned this lesson the hard way throughout a 42-year engineering career.As a young engineer,raising a family,I was more adaptable to management mandates,i.e.,I was more willing to be unethical to keep my job to make money and have health insurance for my family.As I grew in age,experience,and stamina,I was less adaptable,i.e.,I was more ethical.This article tells this story through events at various times in my engineering career1.Ethics define how we do the right thing.展开更多
Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliv...Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliveries. Careful design of the meal preparation and order delivery systems is needed to avoid excessive cust omer waiting time bet ween ordering and delivery. This paper considers the meal preparation and delivery processes simultaneously to approximate average customer waiting time for deliveries. The authors first discuss the system performance with one cook and unit-capacity delivery vehicles, using an M/G/1queue and a GI/G/1queue. Numerical experiments show that our approximation can adequately describe real waiting times. Then, series queues with multiple cooks and multi-capacity delivery vehicles, e.g., an M/G/n queue and a GI/Gn/1 queue, are examined. Results show that except for situations with a large meal preparation time and a small vehicle capacity, compared with the result of simulation, the approximation in this paper is acceptable with a deviation of less than 20%. The marginal decrease in waiting time associated with hiring more vehicles is est.imated under different meal preparation speeds, sizes of service area and vehicle capacities.展开更多
The secondary dendritic arm spacing （SDAS） of free cutting steel 38MnVS during continuous casting process was simulated based on a Mixed Lagrangian and Eulerian Method （MILE Method） and SDAS model. The simulation ...The secondary dendritic arm spacing （SDAS） of free cutting steel 38MnVS during continuous casting process was simulated based on a Mixed Lagrangian and Eulerian Method （MILE Method） and SDAS model. The simulation results are basically in agreement with measured ones. The effect of composition, superheat and casting speed on SDAS are studied, and the relationship between SDAS and interdendritic segregation is discussed. The results show that SDAS increases with increasing carbon and silicon content, and decreases with increasing manganese and sulfur content. The increase of superheat and casting speed also makes SDAS increase. The permeability of co lumnar mushy zone which is parallel to the primary dendritic arms is calculated based on Carman-Kozeny relationship, and the increase of SDAS makes the permeability increase, which exacerbates interdendritic segregation of columnar crystal zone.展开更多
Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monit...Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monitoring well,Yunnan Province.This is the first record of co-seismic effect obtained by mercury vapor observation in China.Such a fact implies that it would be possible to record more information about crustal dynamic effects,such as solid tide,co-seismic effect,etc.,by further improving observation instrument precision and increasing the sampling frequency of the chemical quantity of subsurface fluids.This may help us to raise the capability of earthquake precursor monitoring and forecasting in the future.展开更多
The article is about solving the last mile delivery problem in rural town or village. We want to test the drone’s potential in parcel delivery. The objectives are 1) to introduce the cluster and truck-drone in tandem...The article is about solving the last mile delivery problem in rural town or village. We want to test the drone’s potential in parcel delivery. The objectives are 1) to introduce the cluster and truck-drone in tandem delivery method, 2) to compare the new method with the traditional TSP method in aspect of truck running distance, energy using and time occupation. The parcel delivery demand is sparse, so it is not dense enough for a truck to carry on delivery. We try to identify the best route for the drone to deliver the goods. We use k-mean method to carry on clustering, then we use enumeration method to fulfill the centroids delivery, which comes from the depot. We design a model and calculate the energy, time and distance saving between drone using method(DTSP) and traditional TSP method. The drone attended delivery saves truck delivery distance, energy consumption and time.The truck running distance of DTSP method saves 91.87%, the truck running distance is shortened from 189.69 km to 15.4252 km. The DTSP method saves 90.45% of energy. The DTSP method brings a29.75% cutoff in time aspect when there are two drone in running. The research introduces the cluster and TSP combination method, which is a good way to carry on last mile delivery. The result shows a bright future for drone to attend parcel delivery. The e-commerce corporation can apply this method in practice.展开更多
With continual population growth in the densely populated cities,e.g.,Singapore,traffic congestion is the main transportation problem.As such,Public Transport is deemed as the most sustainable mode of transport.Howeve...With continual population growth in the densely populated cities,e.g.,Singapore,traffic congestion is the main transportation problem.As such,Public Transport is deemed as the most sustainable mode of transport.However,pubic transport is often plagued with the First and Last Mile Problem(FLMP),reducing its appeal especially in the densely populated city areas.The FLMP leads to a wide range of complications,in particular,human congestion in public transport.In this research,after a comprehensive discussion of FLMP problem in densely populated city areas,a case study in Singapore,i.e.,the Kent Ridge Campus of National University of Singapore(KRC-NUS),has been conducted based on the survey and spatio-temporal analyses.In addition to the investigation of FLMP status in the case study area,a new campus shuttle bus route from an alternative MRT station(Haw Par Villa Station)has also been proposed based on the Tabu Search to alleviate the human congestion and current FLMP status for KRC-NUS.This research not only has successfully addressed the FLMP in the case study area,but also can be a good reference for other areas in densely populated cities to help mitigate FLMPs.展开更多
[Objective] The aim was to improve and restore destroyed riverine and water ecosystem and to prevent bio-diversity from deteriorating in Jari demonstration plot in Ethiopia. [Method] Biological engineering and natural...[Objective] The aim was to improve and restore destroyed riverine and water ecosystem and to prevent bio-diversity from deteriorating in Jari demonstration plot in Ethiopia. [Method] Biological engineering and naturalization were made use of to protect nature and restore wetland as per Succession Theory. [Result] Both of eco- environment and eco-functions of Mille River were restored through reconstruction of biocenosis in wetlands. [Conclusion] It is feasible to implement matched ecological projects in semiarid regions in East Africa, providing references for restoration and protection of local water resources.展开更多
The revolution of technology and the rapid evolution of the digital world had a significant effect on the development and expansion of e-commerce.Last mile delivery,for which different app-based delivery services have ...The revolution of technology and the rapid evolution of the digital world had a significant effect on the development and expansion of e-commerce.Last mile delivery,for which different app-based delivery services have recently emerged,is a new area of research that is not thoroughly addressed.Delivery ser-vice is one of the supporting platforms of e-commerce.One of the delivery issues is that many customers experience difficulties in communicating and coordinating with the logistics companies responsible for the delivery service.This challenge is emphasized in this study which introduces a new system to facilitate communica-tion and coordination between customers and logistics companies by using one identity and one interface.This paper is a programming-based study,as the pro-posed system evaluates a website to serve logistics companies as well as designs an application(app)to serve the customers of logistics companies.Swift,a power-ful open-source and object-oriented programming language,and the mark-up language(HTML)were used to build the last mile delivery system.In addition,Firebase,a cloud-hosted real-time database built on Google infrastructure,were used to develop the system.By increasing the level of customer satisfaction and reducing delivery failure rates,this system will eventually increase the prosperity of e-commerce.展开更多
A new method called mixed Lagrangian and Eulerian method （MILE method） was used to simulate the thermomechanical behavior during continuous casting process of steel YF45MnV. The simulation results are basically in a...A new method called mixed Lagrangian and Eulerian method （MILE method） was used to simulate the thermomechanical behavior during continuous casting process of steel YF45MnV. The simulation results are basically in agreement with the measured data. The delaying period at the beginning of solidification is about 0.1. in square root of solidification time which is agreement with the data in literatures, and shell thickness increases in linear relation to square root of solidification time. The bloom surface temperature decreases gradually as the casting proceeds. The effective stress in the comer is much larger than that in the mid-face. The comer area is the dangerous zone of cracking. The effects of mold flux break temperature on the air gap and hot tearing indicator were also modeled. The model predicts that the bloom surface temperature increases with the increase of the mold flux break temperature, but the heat flux decreases with the increase of the mold flux break temperature. ,The hot tearing indicator is much smaller when the mold flux break temperature is higher.展开更多
文摘This study investigates relationships between congestion and travel time performance metrics and crashes on road segments. The study focuses on work zone routes in Iowa, utilizing 2021 commercially-available probe vehicle data and crash data. Travel time performance metrics were derived from the probe vehicle data, and crash counts were obtained from the crash data. Additional variables included road characteristics (traffic volume, road type, segment length) and a categorical variable for the presence of a work zone. A mixed effect linear regression model was employed to identify relationships between road segment crash counts and the selected performance metrics. This was accomplished for two sets of models that include congestion performance measures at different defining threshold values, along with travel time performance measures. The study results indicate that the congestion indicators, certain travel time performance measures, and traffic counts were statistically significant and positively correlated with crash counts. Indicator variables for rural interstate locations and non-active work zones have a stronger influence on crash count than those for municipal interstate locations and active work zones. These findings can inform decision-makers on work zone safety strategies and crash mitigation planning, especially in high traffic volume areas prone to congestion and queues.
基金carried out by NMV on the eastern Goldfields Province of the Yilgarn Craton was as an ARC Linkage-and AMIRA P680-funded postdoctoral research fellow at the Centre for Global Metallogeny,now the Centre for Exploration Targeting,at the University of Western Australia(UWA)
文摘The Neoarchaean Kaigoorlie Gold Field contains the giant Golden Mile and world-class Mt Charlotte deposits,which have been the subject of much research for over 100 years.The Golden Mile deposit is a complex array of ductile to brittle vein and breccia lodes that are predominantly hosted in the highlyfractionated Golden Mile Dolerite sill.The Fimiston lodes comprise an array of narrow lodes that evolved broadly syn- to late-formation of the regional D2 NW-trending foliation.The lodes are characterized by pyrite veinlets and disseminations,quartz veinlets and breccias,and banded quartz-carbonate veins with sericite,carbonate,and pyrite-dominated alteration.Bonanza Green-Leader,or Oroya-style,lodes,with grades in excess of 1000 g/t Au,are similar to the Fimiston-style lodes,but are characterized by abundant visible gold,native tellurium and more abundant telluride minerals within roscoelitebearing alteration zones.The arguably structurally younger Mt Charlotte-style lodes are characterized by a pipe-shaped,coarse-grained quartz,carbonate and scheelite vein-stockwork with distinct verticallyzoned,carbonate-sericite-albite-pyrite ± pyrrhotite dominant alteration assemblages around veins within Unit 8 of the Golden Mile dolerite and porphyry dykes.The network of steep- and gently-dipping extension and shear fracture-fill veins are associated with NE-trending fault se ts that cross cut the regional NW-trend.The deposit area is intruded by swarms of porphyry dykes,including syn-volcanic mafic dykes,early and volumetrically most significant c.2.67 Ga feldspar-phyric porphyry dykes,as well as later c.2.66-2.65 Ga calc-alkaline hornblende-phyric dykes associated with younger c.2.65-2.64 Ga lamprophyre dykes.All post-volcanic dykes have similar orientations to the Fimiston lodes.The feldspar dykes are clearly overprinted by all styles of mineralization,although the relationship between hornblende-phyric and lamprophyre dykes and gold mineralization is more ambiguous.Most agree that gold mineralization was post-peak regiona
文摘There are costs for doing the right thing,but regret is not one of those costs.I learned this lesson the hard way throughout a 42-year engineering career.As a young engineer,raising a family,I was more adaptable to management mandates,i.e.,I was more willing to be unethical to keep my job to make money and have health insurance for my family.As I grew in age,experience,and stamina,I was less adaptable,i.e.,I was more ethical.This article tells this story through events at various times in my engineering career1.Ethics define how we do the right thing.
基金supported by the National Natural Science Foundation of China under Grant No.71661167009the Fundamental Research Funds for the Central Universities under Grant No.B17JB00280
文摘Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliveries. Careful design of the meal preparation and order delivery systems is needed to avoid excessive cust omer waiting time bet ween ordering and delivery. This paper considers the meal preparation and delivery processes simultaneously to approximate average customer waiting time for deliveries. The authors first discuss the system performance with one cook and unit-capacity delivery vehicles, using an M/G/1queue and a GI/G/1queue. Numerical experiments show that our approximation can adequately describe real waiting times. Then, series queues with multiple cooks and multi-capacity delivery vehicles, e.g., an M/G/n queue and a GI/Gn/1 queue, are examined. Results show that except for situations with a large meal preparation time and a small vehicle capacity, compared with the result of simulation, the approximation in this paper is acceptable with a deviation of less than 20%. The marginal decrease in waiting time associated with hiring more vehicles is est.imated under different meal preparation speeds, sizes of service area and vehicle capacities.
基金Item Sponsored by National Natural Science Foundation of China(50874007)
文摘The secondary dendritic arm spacing （SDAS） of free cutting steel 38MnVS during continuous casting process was simulated based on a Mixed Lagrangian and Eulerian Method （MILE Method） and SDAS model. The simulation results are basically in agreement with measured ones. The effect of composition, superheat and casting speed on SDAS are studied, and the relationship between SDAS and interdendritic segregation is discussed. The results show that SDAS increases with increasing carbon and silicon content, and decreases with increasing manganese and sulfur content. The increase of superheat and casting speed also makes SDAS increase. The permeability of co lumnar mushy zone which is parallel to the primary dendritic arms is calculated based on Carman-Kozeny relationship, and the increase of SDAS makes the permeability increase, which exacerbates interdendritic segregation of columnar crystal zone.
基金sponsored by the Earthquake Science and Technology Spark Plan,China (XH15041Y)
文摘Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monitoring well,Yunnan Province.This is the first record of co-seismic effect obtained by mercury vapor observation in China.Such a fact implies that it would be possible to record more information about crustal dynamic effects,such as solid tide,co-seismic effect,etc.,by further improving observation instrument precision and increasing the sampling frequency of the chemical quantity of subsurface fluids.This may help us to raise the capability of earthquake precursor monitoring and forecasting in the future.
基金Supported by China Scholarship Council(201507090026)
文摘The article is about solving the last mile delivery problem in rural town or village. We want to test the drone’s potential in parcel delivery. The objectives are 1) to introduce the cluster and truck-drone in tandem delivery method, 2) to compare the new method with the traditional TSP method in aspect of truck running distance, energy using and time occupation. The parcel delivery demand is sparse, so it is not dense enough for a truck to carry on delivery. We try to identify the best route for the drone to deliver the goods. We use k-mean method to carry on clustering, then we use enumeration method to fulfill the centroids delivery, which comes from the depot. We design a model and calculate the energy, time and distance saving between drone using method(DTSP) and traditional TSP method. The drone attended delivery saves truck delivery distance, energy consumption and time.The truck running distance of DTSP method saves 91.87%, the truck running distance is shortened from 189.69 km to 15.4252 km. The DTSP method saves 90.45% of energy. The DTSP method brings a29.75% cutoff in time aspect when there are two drone in running. The research introduces the cluster and TSP combination method, which is a good way to carry on last mile delivery. The result shows a bright future for drone to attend parcel delivery. The e-commerce corporation can apply this method in practice.
文摘With continual population growth in the densely populated cities,e.g.,Singapore,traffic congestion is the main transportation problem.As such,Public Transport is deemed as the most sustainable mode of transport.However,pubic transport is often plagued with the First and Last Mile Problem(FLMP),reducing its appeal especially in the densely populated city areas.The FLMP leads to a wide range of complications,in particular,human congestion in public transport.In this research,after a comprehensive discussion of FLMP problem in densely populated city areas,a case study in Singapore,i.e.,the Kent Ridge Campus of National University of Singapore(KRC-NUS),has been conducted based on the survey and spatio-temporal analyses.In addition to the investigation of FLMP status in the case study area,a new campus shuttle bus route from an alternative MRT station(Haw Par Villa Station)has also been proposed based on the Tabu Search to alleviate the human congestion and current FLMP status for KRC-NUS.This research not only has successfully addressed the FLMP in the case study area,but also can be a good reference for other areas in densely populated cities to help mitigate FLMPs.
基金Supported by South-South Cooperation Project of SSC/SPFS-FAO-Ethiopia-China~~
文摘[Objective] The aim was to improve and restore destroyed riverine and water ecosystem and to prevent bio-diversity from deteriorating in Jari demonstration plot in Ethiopia. [Method] Biological engineering and naturalization were made use of to protect nature and restore wetland as per Succession Theory. [Result] Both of eco- environment and eco-functions of Mille River were restored through reconstruction of biocenosis in wetlands. [Conclusion] It is feasible to implement matched ecological projects in semiarid regions in East Africa, providing references for restoration and protection of local water resources.
文摘The revolution of technology and the rapid evolution of the digital world had a significant effect on the development and expansion of e-commerce.Last mile delivery,for which different app-based delivery services have recently emerged,is a new area of research that is not thoroughly addressed.Delivery ser-vice is one of the supporting platforms of e-commerce.One of the delivery issues is that many customers experience difficulties in communicating and coordinating with the logistics companies responsible for the delivery service.This challenge is emphasized in this study which introduces a new system to facilitate communica-tion and coordination between customers and logistics companies by using one identity and one interface.This paper is a programming-based study,as the pro-posed system evaluates a website to serve logistics companies as well as designs an application(app)to serve the customers of logistics companies.Swift,a power-ful open-source and object-oriented programming language,and the mark-up language(HTML)were used to build the last mile delivery system.In addition,Firebase,a cloud-hosted real-time database built on Google infrastructure,were used to develop the system.By increasing the level of customer satisfaction and reducing delivery failure rates,this system will eventually increase the prosperity of e-commerce.
基金Project(51174020) supported by the National Natural Science Foundation of China
文摘A new method called mixed Lagrangian and Eulerian method （MILE method） was used to simulate the thermomechanical behavior during continuous casting process of steel YF45MnV. The simulation results are basically in agreement with the measured data. The delaying period at the beginning of solidification is about 0.1. in square root of solidification time which is agreement with the data in literatures, and shell thickness increases in linear relation to square root of solidification time. The bloom surface temperature decreases gradually as the casting proceeds. The effective stress in the comer is much larger than that in the mid-face. The comer area is the dangerous zone of cracking. The effects of mold flux break temperature on the air gap and hot tearing indicator were also modeled. The model predicts that the bloom surface temperature increases with the increase of the mold flux break temperature, but the heat flux decreases with the increase of the mold flux break temperature. ,The hot tearing indicator is much smaller when the mold flux break temperature is higher.
