Road accessibility is considered to be one of the major factors influencing (or correlated to) rural households’ access to- and participation in markets. However, there are few studies that investigate this important...Road accessibility is considered to be one of the major factors influencing (or correlated to) rural households’ access to- and participation in markets. However, there are few studies that investigate this important topic. This paper, therefore, explores the issue from both theoretical and practical perspectives with household and village level data from Northern Ethiopia. It is generally assumed that road accessibility significantly contributes to both access to- and participation in markets by rural households. The results in this study, however, suggest that neither participation in major markets nor the amount of purchased agricultural inputs use are significantly different for households with respect to the degree of road accessibility in the study area. Nevertheless, the situation seems somewhat better in locations with good access to roads. On the other hand, the results in this study confirm that road accessibility significantly contributes to reducing farm gate prices of manufactured goods and increasing farm gate prices of agricultural goods.展开更多
A numerical study based on a two-dimensional two-phase SPH(Smoothed Particle Hydrodynamics)model to analyze the action of water waves on open-type sea access roads is presented.The study is a continuation of the analy...A numerical study based on a two-dimensional two-phase SPH(Smoothed Particle Hydrodynamics)model to analyze the action of water waves on open-type sea access roads is presented.The study is a continuation of the analyses presented by Chen et al.(2022),in which the sea access roads are semi-immersed.In this new configuration,the sea access roads are placed above the still water level,therefore the presence of the air phase becomes a relevant issue in the determination of the wave forces acting on the structures.Indeed,the comparison of wave forces on the open-type sea access roads obtained from the single and two-phase SPH models with the experimental results shows that the latter are in much better agreement.So in the numerical simulations,a two-phaseδ-SPH model is adopted to investigate the dynamical problems.Based on the numerical results,the maximum horizontal and uplifting wave forces acting on the sea access roads are analyzed by considering different wave conditions and geometries of the structures.In particular,the presence of the girder is analyzed and the differences in the wave forces due to the air cushion effects which are created below the structure are highlighted.展开更多
文摘Road accessibility is considered to be one of the major factors influencing (or correlated to) rural households’ access to- and participation in markets. However, there are few studies that investigate this important topic. This paper, therefore, explores the issue from both theoretical and practical perspectives with household and village level data from Northern Ethiopia. It is generally assumed that road accessibility significantly contributes to both access to- and participation in markets by rural households. The results in this study, however, suggest that neither participation in major markets nor the amount of purchased agricultural inputs use are significantly different for households with respect to the degree of road accessibility in the study area. Nevertheless, the situation seems somewhat better in locations with good access to roads. On the other hand, the results in this study confirm that road accessibility significantly contributes to reducing farm gate prices of manufactured goods and increasing farm gate prices of agricultural goods.
基金supported by the New Cornerstone Science Foundation through the XPLORER PRIZE and the National Natural Science Foundation of China(Grant No.52088102).
文摘A numerical study based on a two-dimensional two-phase SPH(Smoothed Particle Hydrodynamics)model to analyze the action of water waves on open-type sea access roads is presented.The study is a continuation of the analyses presented by Chen et al.(2022),in which the sea access roads are semi-immersed.In this new configuration,the sea access roads are placed above the still water level,therefore the presence of the air phase becomes a relevant issue in the determination of the wave forces acting on the structures.Indeed,the comparison of wave forces on the open-type sea access roads obtained from the single and two-phase SPH models with the experimental results shows that the latter are in much better agreement.So in the numerical simulations,a two-phaseδ-SPH model is adopted to investigate the dynamical problems.Based on the numerical results,the maximum horizontal and uplifting wave forces acting on the sea access roads are analyzed by considering different wave conditions and geometries of the structures.In particular,the presence of the girder is analyzed and the differences in the wave forces due to the air cushion effects which are created below the structure are highlighted.
