The rapid urban growth in developing city increases the requirement of the efficient and sustainable public transportation system.The urban growth affects the urban form,which indicates the change in human and urban d...The rapid urban growth in developing city increases the requirement of the efficient and sustainable public transportation system.The urban growth affects the urban form,which indicates the change in human and urban development activity.Urban form affects directly and indirectly access to the public transportation system as an assessment of potential riders and proximity to stops increase transit services users.Therefore,access is one of the important aspects for the assessment of transit service efficiency.Public transportation access can be represented by a coverage area and useful to estimate potential riders of public transportation.In this study,a Geographical Information System(GIS)-based spatial statistical analysis method is used to examine the spatial relationship of different urban form indicators with population or riders of transit service in a coverage area and to ascertain how urban form influences public transportation trips in this coverage area.The coverage area is delineated using a GIS-based road/street network distance approach.The spatial analysis results suggested that urban forms have certain impact on trips in coverage area at both ward level and zone level.The statistical analysis implies that significant and positive values of spatial lag coefficient indicate a positive spatial interaction between wards and variable like total coverage area;worker density have shown positive and significant effects on trips of public transportation.展开更多
The extraction of ethanol with the solvents of aldehydes mixed with m-xylene was studied for the bioethanol concentration process.Furfural and benzaldehyde were selected as extraction solvents,with which the solubilit...The extraction of ethanol with the solvents of aldehydes mixed with m-xylene was studied for the bioethanol concentration process.Furfural and benzaldehyde were selected as extraction solvents,with which the solubility of water is small,expecting large distribution coefficient of ethanol.The liquid–liquid two-phase region was the largest with m-xylene solvent,followed by benzaldehyde and furfural.The region of two liquid–liquid phase became larger with the mixed solvent of m-xylene and furfural than that with furfural solvent.The NRTL model was applied to the ethanol–water–furfural–m-xylene system,and the model could well express the liquid–liquid equilibrium of the system.For any solvent used in this study,the separation selectivity of ethanol relative to water decreased as the distribution coefficient of ethanol increased.The separation selectivity with m-xylene was the largest among the employed solvents,but the distribution coefficient was the smallest.The solvent mixture of furfural and m-xylene showed relatively high distribution coefficient of ethanol and separation selectivity,even in the higher mass fraction of m-xylene in the solvent phase.The ethanol extraction with a countercurrent multistage extractor by a continuous operation was simulated to evaluate the extraction performance.The ethanol content could be concentrated in the extract phase with relatively small number of extraction stages but low yield of ethanol was obtained.展开更多
The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes wi...The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results.展开更多
Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especiall...Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS （blast furnace slag） and FA （fly ash） is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that： （1） Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC （ordinary Portland cement） specimens; （2） Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; （3） Total life time （corrosion incubation period and propagation period） of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.展开更多
There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cra...There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cracks are almost harmless. So, a good guideline regarding how to deal with cracks in concrete structures is needed. In this guideline, the practical investigation, repair and strengthening method of cracked concrete structures is discussed. And the detecting subjects are cracks generated immediately after casting and during the service time. This guideline targets on the owners （including managers） of concrete structure and the engineers working for the maintenance of concrete structure. JCI （Japan Concrete Institute） published first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures--2009＂ was published. This guideline is very practical when cracks are observed in existing concrete structures, in any other countries as well as in Japan. These three authors led the establishment of this guideline.展开更多
Manganese (Mn) is an essential element for human body. However, elevated concentration of manganese causes severe problem and disease. Acid mine drainage (AMD), wastewater generated due to open-pit mining, commonly co...Manganese (Mn) is an essential element for human body. However, elevated concentration of manganese causes severe problem and disease. Acid mine drainage (AMD), wastewater generated due to open-pit mining, commonly contains Mn with exceeded concentration. This study is to investigate the improvement of ball-milling modified Indonesian natural bentonite (INB) for manganese (Mn) removal from AMD and to increase the pH through batch and column sorption test as a passive treatment system approach. The batch sorption test result showed the maximum Mn adsorbed (Qm) on INB from the Langmuir model increased from 4.69 to 17.12 mg/g after milling. The column sorption test result also showed the amount of Mn adsorbed on INB until breakthrough time (qu) and until saturation time (q) increased after milling. The qu increased from 1.27 to 10.06 mg/g, and the q increased from 4.55 to 12.91 mg/g. The mass transfer zone (MTZ) became significantly shorter after milling from 0.22 to 0.07 cm. The Thomas model exhibited the equilibrium uptake of Mn (q0) increased after milling from 3.91 to 13.72 mg/g. In equilibrium condition, both unmilled and milled INB showed the pH increased from ≈3 to 8.展开更多
There are many cracked concrete structures, although there have been numerous efforts to eliminate cracks. Some cracks are very harmful and should be repaired as soon as possible. On the other hand, the other cracks a...There are many cracked concrete structures, although there have been numerous efforts to eliminate cracks. Some cracks are very harmful and should be repaired as soon as possible. On the other hand, the other cracks are almost harmless. So, a good guideline about how to deal with cracks in concrete structures had been needed. JCI （Japan Concrete Institute） published the first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, the second version in 1987, the third version in 2003, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures-2009＂ was published. This Guideline is very practical, when cracks are observed in existed concrete structures, in any other countries as well as in Japan.展开更多
Deactivation of solid catalyst often occurs in biodiesel production. In this work, deactivated modified red mud catalysts used in biodiesel production were regenerated with hexane and calcination treatments. The deact...Deactivation of solid catalyst often occurs in biodiesel production. In this work, deactivated modified red mud catalysts used in biodiesel production were regenerated with hexane and calcination treatments. The deactivated and regenerated catalysts were characterized using XRD, FTIR, SEM, TG, N2 adsorption, measured for their basic strength, and tested in the transesterification of canola oil. The results revealed that the main cause of the catalyst deactivation is due to obstruction of the active sites by contaminants. The regeneration by washing with hexane followed by calcination can effectively improve the properties of the deactivated catalyst and increase its catalytic activity.展开更多
Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological anal...Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological analysis （SEM）, mineralogical composition （XRD） and CEC （cation exchange capacity）. LOI （Loss of ignition） of rice husk ash was also evaluated. Result indicated that the rice husk ash sample from Roi-Et Green power plant in the Northeastern of Thailand with combustion temperature of 650 ℃ has a high content of SiO2 （above 90 wt.%）. Zeolite-X from rice husk ash with high content of Si was successfully synthesized using hydrothermal treatment. The zeolitic material synthesized with the optimal condition possessed a maximum value of CEC of 503 meq/100g, and it has potentiality to be used as ion exchangers.展开更多
文摘The rapid urban growth in developing city increases the requirement of the efficient and sustainable public transportation system.The urban growth affects the urban form,which indicates the change in human and urban development activity.Urban form affects directly and indirectly access to the public transportation system as an assessment of potential riders and proximity to stops increase transit services users.Therefore,access is one of the important aspects for the assessment of transit service efficiency.Public transportation access can be represented by a coverage area and useful to estimate potential riders of public transportation.In this study,a Geographical Information System(GIS)-based spatial statistical analysis method is used to examine the spatial relationship of different urban form indicators with population or riders of transit service in a coverage area and to ascertain how urban form influences public transportation trips in this coverage area.The coverage area is delineated using a GIS-based road/street network distance approach.The spatial analysis results suggested that urban forms have certain impact on trips in coverage area at both ward level and zone level.The statistical analysis implies that significant and positive values of spatial lag coefficient indicate a positive spatial interaction between wards and variable like total coverage area;worker density have shown positive and significant effects on trips of public transportation.
文摘The extraction of ethanol with the solvents of aldehydes mixed with m-xylene was studied for the bioethanol concentration process.Furfural and benzaldehyde were selected as extraction solvents,with which the solubility of water is small,expecting large distribution coefficient of ethanol.The liquid–liquid two-phase region was the largest with m-xylene solvent,followed by benzaldehyde and furfural.The region of two liquid–liquid phase became larger with the mixed solvent of m-xylene and furfural than that with furfural solvent.The NRTL model was applied to the ethanol–water–furfural–m-xylene system,and the model could well express the liquid–liquid equilibrium of the system.For any solvent used in this study,the separation selectivity of ethanol relative to water decreased as the distribution coefficient of ethanol increased.The separation selectivity with m-xylene was the largest among the employed solvents,but the distribution coefficient was the smallest.The solvent mixture of furfural and m-xylene showed relatively high distribution coefficient of ethanol and separation selectivity,even in the higher mass fraction of m-xylene in the solvent phase.The ethanol extraction with a countercurrent multistage extractor by a continuous operation was simulated to evaluate the extraction performance.The ethanol content could be concentrated in the extract phase with relatively small number of extraction stages but low yield of ethanol was obtained.
基金supported by KAKENHI Grant Numbers 23760441 and 24360193The authors would like to expresstheir gratitude to Japan Society for the Promotion of Science(JSPS)
文摘The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results.
文摘Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS （blast furnace slag） and FA （fly ash） is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that： （1） Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC （ordinary Portland cement） specimens; （2） Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; （3） Total life time （corrosion incubation period and propagation period） of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.
文摘There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cracks are almost harmless. So, a good guideline regarding how to deal with cracks in concrete structures is needed. In this guideline, the practical investigation, repair and strengthening method of cracked concrete structures is discussed. And the detecting subjects are cracks generated immediately after casting and during the service time. This guideline targets on the owners （including managers） of concrete structure and the engineers working for the maintenance of concrete structure. JCI （Japan Concrete Institute） published first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures--2009＂ was published. This guideline is very practical when cracks are observed in existing concrete structures, in any other countries as well as in Japan. These three authors led the establishment of this guideline.
文摘Manganese (Mn) is an essential element for human body. However, elevated concentration of manganese causes severe problem and disease. Acid mine drainage (AMD), wastewater generated due to open-pit mining, commonly contains Mn with exceeded concentration. This study is to investigate the improvement of ball-milling modified Indonesian natural bentonite (INB) for manganese (Mn) removal from AMD and to increase the pH through batch and column sorption test as a passive treatment system approach. The batch sorption test result showed the maximum Mn adsorbed (Qm) on INB from the Langmuir model increased from 4.69 to 17.12 mg/g after milling. The column sorption test result also showed the amount of Mn adsorbed on INB until breakthrough time (qu) and until saturation time (q) increased after milling. The qu increased from 1.27 to 10.06 mg/g, and the q increased from 4.55 to 12.91 mg/g. The mass transfer zone (MTZ) became significantly shorter after milling from 0.22 to 0.07 cm. The Thomas model exhibited the equilibrium uptake of Mn (q0) increased after milling from 3.91 to 13.72 mg/g. In equilibrium condition, both unmilled and milled INB showed the pH increased from ≈3 to 8.
文摘There are many cracked concrete structures, although there have been numerous efforts to eliminate cracks. Some cracks are very harmful and should be repaired as soon as possible. On the other hand, the other cracks are almost harmless. So, a good guideline about how to deal with cracks in concrete structures had been needed. JCI （Japan Concrete Institute） published the first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, the second version in 1987, the third version in 2003, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures-2009＂ was published. This Guideline is very practical, when cracks are observed in existed concrete structures, in any other countries as well as in Japan.
文摘Deactivation of solid catalyst often occurs in biodiesel production. In this work, deactivated modified red mud catalysts used in biodiesel production were regenerated with hexane and calcination treatments. The deactivated and regenerated catalysts were characterized using XRD, FTIR, SEM, TG, N2 adsorption, measured for their basic strength, and tested in the transesterification of canola oil. The results revealed that the main cause of the catalyst deactivation is due to obstruction of the active sites by contaminants. The regeneration by washing with hexane followed by calcination can effectively improve the properties of the deactivated catalyst and increase its catalytic activity.
文摘Thailand rice husk ash was used to synthesize zeolite by hydrothermal treatment. Raw rice husk ash material and zeolitic products were characterized in terms of specific surface area （BET method）, morphological analysis （SEM）, mineralogical composition （XRD） and CEC （cation exchange capacity）. LOI （Loss of ignition） of rice husk ash was also evaluated. Result indicated that the rice husk ash sample from Roi-Et Green power plant in the Northeastern of Thailand with combustion temperature of 650 ℃ has a high content of SiO2 （above 90 wt.%）. Zeolite-X from rice husk ash with high content of Si was successfully synthesized using hydrothermal treatment. The zeolitic material synthesized with the optimal condition possessed a maximum value of CEC of 503 meq/100g, and it has potentiality to be used as ion exchangers.
