The Phewa watershed is under constant landslide threat because of its complicated topography,climate,and biology.The floral structure of landslide-prone areas possesses a significant impact on determining the ecologic...The Phewa watershed is under constant landslide threat because of its complicated topography,climate,and biology.The floral structure of landslide-prone areas possesses a significant impact on determining the ecological processes involved in slope stabilization.Plant roots,for example,serve as physical anchors in the soil,enhancing slope stability.Therefore,this study aims to determine appropriate plant species that can enhance soil stability in Phewa Watershed by examining their floral structure in landslide areas.Floral diversity was assessed throughout field visits.Ten of the 46 landslides were selected with 15 plots based on aspect,watershed zones,and normalized difference vegetation index(NDVI)value.Six plant species were selected to evaluate root traits,uprooting force,and cellulosic testing based on their Important Value Index(IVI)value,native characteristics,and regeneration.The uprooting force was calculated using a‘winch’with a force transducer,while the root characteristics were measured manually and using‘ImageJ software’.Results show that 319 species from 92 families are registered in the buffer zones and landslide scars,and the NDVI suggest that vegetation covers more than 49%of the landslide areas.The floral composition of the landslides in the 15 plots contains 140 species from 52 families,with Poaceae dominating.In six plant species,the Ochiai index suggests a significant level of association.The uprooting force is correlated to the root diameter and number but is insignificant in terms of root length and area.Saccharum spontaneum is the best option for landslide stability based on uprooting force(882.63±245.175)N,cellulose content(67.038±4.766)%and root number characteristic(69.333±24.338)whereas Themeda arundinacea is preferred due to its root diameter traits(0.054±0.022)cm.Finally,it emphasizes the significance of selecting key species in lowering the risk of landslides,strengthening soil stability,and building resilient ecosystems in susceptible watershed areas.展开更多
Atmospheric nanoparticles(PM<0.1μm)are a major cause of environmental problems and also affect health risk.To control and reduce these problems,sources identification of atmospheric particulates is necessary.Combu...Atmospheric nanoparticles(PM<0.1μm)are a major cause of environmental problems and also affect health risk.To control and reduce these problems,sources identification of atmospheric particulates is necessary.Combustion of bituminous coal and biomass includ-ing rubber wood,palm kernel,palm fiber,rice stubble,rice straw,maize residue,sugarcane leaves and sugarcane bagasse,which are considered as sources of air quality problems in many countries,was performed.Emissions of particle-bound chemical components includ-ing organic carbon(OC),elemental carbon(EC),water-soluble ions(NH4^(+),Cl^(-),NO_(3)^(-),SO_(4)^(2-)),elements(Ca,K,Mg,Na)and heavy metals(Cd,Cr,Ni,Pb)were investigated.The results re-vealed that PM<0.1μm from all samples was dominated by the OC component(>50%)with minor contribution from EC(3%-12%).The higher fraction of carbonaceous components was found in the particulates with smaller sizes,and lignin content may relate to concentration of pyrolyzed organic carbon(PyOC)resulting in the differences of OC/EC values.PM emit-ted from burning palm fiber and rice stubble showed high values of OC/EC and also high PyOC.Non-carbonaceous components such as Cl^(-),Cr,Ca,Cd,Ni,Na and Mg may be useful as source indicators,but they did not show any correlation with the size of PM.展开更多
In recent times,multiple Unmanned Aerial Vehicles(UAVs)are being widely utilized in several areas of applications such as agriculture,surveillance,disaster management,search and rescue operations.Degree of robustness ...In recent times,multiple Unmanned Aerial Vehicles(UAVs)are being widely utilized in several areas of applications such as agriculture,surveillance,disaster management,search and rescue operations.Degree of robustness of applied control schemes determines how accurate a swarm of UAVs accomplish group tasks.Formation and trajectory tracking controllers are required for the swarm of multiple UAVs.Factors like external environmental effects,parametric uncertainties and wind gusts make the controller design process as a challenging task.This article proposes fractional order formation and trajectory tacking controllers for multiple quad-rotors using Super Twisting Sliding Mode Control(STSMC)technique.To compensate the effects of the disturbances due to parametric uncertainties and wind gusts,Lyapunov function based adaptive controllers are formulated.Moreover,Lyapunov theorem is used to guarantee the stability of the proposed controllers.Three types of controllers,namely fixed gain STSMC and fractional order Adaptive Super Twisting Sliding Mode Control(ASTSMC)methods are tested for the swarm of UAVs by performing the numerical simulations in MATLAB/Simulink environment.From the presented results,it is verified that in presence of wind disturbances and parametric uncertainties,the proposed fractional order ASTSMC technique showed improved robustness as compared to the fixed gain STSMC and integer order ASTSMC.展开更多
Objective: To examine the resurgence rate, house density index(HDI) and parous rate of the Aedes aegypti vector after space spraying carried out by the routine spraying team,and compare with the rates after standard i...Objective: To examine the resurgence rate, house density index(HDI) and parous rate of the Aedes aegypti vector after space spraying carried out by the routine spraying team,and compare with the rates after standard indoor ultra low volume(SID-ULV) spraying carried out by the trained research spraying team.Methods: Between March and September 2014, a cluster randomized controlled trial including 12 clusters(6 regular ULV, 6 SID-ULV) with totally 4 341 households was conducted, and around 20–31 houses in each cluster were selected for assessment. The parous rate and HDI of collected mosquitoes 2 days before and 1, 2 and 6 days after spraying were obtained and compared.Results: The HDI dropped significantly from the baseline 1 and 2 days after spraying to a non-zero value in the SID-ULV treated locations but not in the regular ULV group locations. However, by 6 days after spraying, the HDI of both groups had returned to the base value measured 2 days before spraying. There were no statistically significant differences in the parous rate between groups.Conclusions: SID-ULV is more effective in reducing Aedes aegypti populations.However, rapid resurgence of dengue vector after spraying in urban areas was observed in both groups.展开更多
Transboundary and domestic aerosol transport during 2018–2019 affecting Bangkok air quality has been investigated.Physicochemical characteristics of size-segregated ambient particles down to nano-particles collected ...Transboundary and domestic aerosol transport during 2018–2019 affecting Bangkok air quality has been investigated.Physicochemical characteristics of size-segregated ambient particles down to nano-particles collected during 2017 non-haze and 2018–2019 haze periods were analyzed.The average PM2.5 concentrations at KU and KMUTNB sites in Bangkok,Thailand during the haze periods were about 4 times higher than in non-haze periods.The highest average organic carbon and elemental carbon concentrations were 4.6±2.1μg/m3 and 1.0±0.4μg/m3,respectively,in PM0.5–1.0 range at KU site.The values of OC/EC and charEC/soot-EC ratios in accumulation mode particles suggested the significant influence of biomass burning,while the nuclei and coarse mode particles were from mixed sources.PAH concentrations during 2018–2019 haze period at KU and KMUTNB were 3.4±0.9 ng/m3 and 1.8±0.2 ng/m3,respectively.The PAH diagnostic ratio of PM2.5 also suggested the main contributions were from biomass combustion.This is supported by the 48-hrs backward trajectory simulation.The higher PM2.5 concentrations during 2018–2019 haze period are also associated with the meteorological conditions that induce thermal inversions and weak winds in the morning and evening.Average values of benzo(a)pyrene toxic equivalency quotient during haze period were about 3–6 times higher than during non-haze period.This should raise a concern of potential human health risk in Bangkok and vicinity exposing to fine and ultrafine particulate matters in addition to regular exposure to traffic emission.展开更多
Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation ...Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation (LRAT) to the level of PAHs in the rural atmosphere of Whitbourne,UK.In general,higher R-values coupled with lower P-values were found in those samples within a radius of 300 miles,whereas lower R-values were detected in those samples within a radius of 60 miles.R-values of PAH concentrations vs.all vehicle numbers within radius of 300 miles ranged from 0.51 to 0.92 with the arithmetic mean of 0.75 ± 0.12,whilst those R-values within a radius of 60 miles ranged from 0.05 to 0.61 with the arithmetic mean of 0.11 ± 0.28.This supports the hypothesis that PAHs in Whitbourne undergo LRAT.展开更多
Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthre...Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthrene,Ret:retene,B[a]A:benzo[a]anthracene,Chry:chrysene,B[b,j,k]F:benzo[b,j,k]fluoranthene,B[e]P:benzo[e]pyrene,B[a]P:benzo[a]pyrene,Ind:indeno[1,2,3-cd]pyrene,B[g,h,i]P:benzo[g,h,i]perylene)at Whitbourne,UK,were estimated by using the rate constants for reaction with OH,O3,and the first order rate constants of eight species of high molecular weight PAHs(i.e.B[a]A,Chry,B[b]F,B[k]F,B[a]P,Ind,B[g,h,i]P and Ret)as a function of humidity,solar intensity and temperature by using Multiple Regression Analysis.The predicted atmospheric lifetime of Ac,Ace,Ph,MePh3,MePh9,MePh2 and MePh1 ranged between 11.42 h-79.12 h in cold period and 1/31 h-14.33 h in warm period respectively.The binary ratios of atmospheric lifetime of B[k]F/B[g,h,i]P,B[k]F/B[g,h,i]P,B[g,h,i]P/Ind and B[k]F/Ind displayed non-significant differences between cold and warm period,indicating that high molecular weight PAHs are difficult to be decomposed by UV light and thus may be conveyed to the rural regions via long range atmospheric transportation(LRAT).The decreased level of the atmospheric lifetime of low molecular weight PAHs in summer can be attributed to an increased level of OH radical content and solar radiation.展开更多
<div style="text-align:justify;"> Size-segregated of particulate matter (PM) including PM<sub>0.1</sub> at two different sites, i.e., educational (EA) and residential (RA) areas in Padang c...<div style="text-align:justify;"> Size-segregated of particulate matter (PM) including PM<sub>0.1</sub> at two different sites, i.e., educational (EA) and residential (RA) areas in Padang city, Indonesia were sampled by using a cascade type air sampler for 24 hours with the average flowrate 40 l/m throughout three weeks (March, 08<sup>th</sup>-25<sup>th</sup> 2018). Carbonaceous components were analyses by a carbon analyzer following the IMPROVE_TOR protocol. Average PM<sub>2.5</sub> and PM<sub>10</sub> concentrations in RA were higher than those in EA while being below the NAAQS of Indonesia. However, it was much higher compared to the WHO limit for 24 hours in RA. OC was the dominant fraction in TC. OC/EC ratio ranging from 2.4 to 33.0 was similar at both sites, suggesting the OC was emitted from various sources. Char-EC and soot-EC ratio were founded to be minimized for PM<sub>0.1</sub> (0.40 ± 0.27 and 0.39 ± 0.39, respectively at each site), indicating a more influence of burning of fossil fuel as vehicles exhaust and coal combustion. The transboundary influence of open biomass burning was not so significant although it cannot be ignored. </div>展开更多
Distribution of PM_(0.1),PM_(1) and PM_(2.5) particle-and gas-polycyclic aromatic hydrocarbons(PAHs)during the 2019 normal,partial and strong haze periods at a background location in southern Thailand were investigate...Distribution of PM_(0.1),PM_(1) and PM_(2.5) particle-and gas-polycyclic aromatic hydrocarbons(PAHs)during the 2019 normal,partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic risks.PM1 was the predominant component,during partial and strong haze periods,accounting for 45.1% and 52.9% of total suspended particulate matter,respectively,while during normal period the contribution was only 34.0%.PM_(0.1) concentrations,during the strong haze period,were approximately 2 times higher than those during the normal period.Substantially increased levels of particle-PAHs for PM_(0.1),PM_(1) and PM_(2.5) were observed during strong haze period,about 3,5 and 6 times higher than those during normal period.Gas-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM_(2.5).Average total Benzo[a]Pyrene Toxic Equivalency Quotients(BaP-TEQ)in PM_(0.1),PM_(1) and PM_(2.5) during haze periodswere about 2–6 times higher than in the normal period.The total accumulated Incremental Lifetime Cancer Risks(ILCRs)in PM_(0.1),PM_(1) and PM_(2.5) for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in nonhaze scenario,indicating a higher potential carcinogenic risk.These observations suggest PM_(0.1),PM_(1) and PM_(2.5) were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland fires.This leads to an increase in the volume of smoke aerosol,exerting a significant impact on air quality in southern Thailand,as well as many other countries in lower southeast Asia.展开更多
Objective:To demonstrate the effect of indoor spraying and window screens on Aedes aegypti mosquito density after space spraying.Methods:A total of 141 households(the study houses)in six communities of Songkhla City,l...Objective:To demonstrate the effect of indoor spraying and window screens on Aedes aegypti mosquito density after space spraying.Methods:A total of 141 households(the study houses)in six communities of Songkhla City,located in Songkhla Province of southern Thailand,were randomly selected and the adult Ae.aegypti populations were assessed pre-and post-insecticide spraying from March to October,2014.Houses close to(within a 20 m radius)the study houses were analyzed using spatial analysis tools.The Aedes aegypti density in the study houses and house density index were compared with the density in the neighbouring houses,based on three spraying conditions:(i)unsprayed(ii)only outdoor sprayed and(iii)indoor plus outdoor sprayed.Results:Only spraying houses indoors was the most effective(P<0.05).There was insufficient evidence that the source of the increase in the number of mosquitoes in unsprayed houses was due to their migration from neighbouring houses which had been sprayed.However,the study houses without screens on their windows were found to have a likely higher dengue vector population after spraying,but the difference was not significant.Conclusions:In dengue endemic areas,all houses should be fully screened and the number of houses ultra-low volume sprayed indoor plus outdoor should be increased with the cooperation of householders and communities during epidemics.展开更多
This article concentrates on the aeration efficiency of venturi air injectors in aquaculture or wastewater treatment.This study was designed to investigate the location of the dissolved oxygen(DO)sensor installation,w...This article concentrates on the aeration efficiency of venturi air injectors in aquaculture or wastewater treatment.This study was designed to investigate the location of the dissolved oxygen(DO)sensor installation,with a focus on investigating the aeration mechanism by studying ten variables,including temperature,pH,oxidation-reduction potential(ORP),electrical conductivity,resistivity,total dissolved solids,salinity,pressure,dissolved oxygen,and the effect of changing the position of DO sensor installations in different locations via oxygen transfer.The water temperature was raised due to the heating of the water pump.It ranged from 29.7°C to 32.78°C,with different temperatures resulting in different oxygen solubility.The pH level increased with the rise in oxygen levels due to an increase in OH-concentration,whereas the ORP decreased when oxygen levels rose,increasing the reduction reaction.A study on the effect of changing the position of DO sensor installations in different locations was discovered using oxygen transfer coefficients(K_(La))variables.The K_(La)values at nozzle depths of 15 cm,30 cm,and 45 cm were 0.0004±0.0001,0.00042±0.0001,and 0.00136±0.00013,respectively.Therefore,there is a slight difference of K_(La)value when changing the position of sensor installations.An inappropriate distance between the DO sensor and nozzle installation is able to cause turbulent flow.This event resulted in an incorrect DO value.Moreover,the installation of the DO sensor too far from the nozzle resulted in a low value of DO.展开更多
Disaster risk reduction has become a global strategy for making cities more resilient since the establishment of the Hyogo Framework for Action in 2005. The question that still challenges emergency management scholars...Disaster risk reduction has become a global strategy for making cities more resilient since the establishment of the Hyogo Framework for Action in 2005. The question that still challenges emergency management scholars and professionals, however, is what contributes to the progress of resilience building. Previous literature suggests that disaster resilience can be attributable to multiple factors, including leadership. But the specific abilities that help leaders promote resilience have not yet been examined empirically. To address this problem, using the United Nations International Strategy for Disaster Reduction 10 Essentials for Making Cities Resilient as guidelines, we assessed the progress of flood resilience building in Thailand and its relationship to local government leaders' abilities. Our research showed that, since the flood disaster in 2011, municipalities in Thailand have made moderate progress in flood resilience building. The results of a multiple regression analysis revealed that disaster resilience leadership abilities have had a statistically significant, positive effect on the progress of flood resilience building. Our findings underscore the role of leadership in making cities more resilient and shed light on how local government leaders can contribute to the progress ofdisaster risk reduction. We also outline the academic implications and practical contributions of our research.展开更多
For the manufacture of working parts of agricultural tools operating in soil,various structural materials are used:alloy and low-alloy steels,weld materials for hardfacing,and plates made from cementedcarbide.Manufact...For the manufacture of working parts of agricultural tools operating in soil,various structural materials are used:alloy and low-alloy steels,weld materials for hardfacing,and plates made from cementedcarbide.Manufacturers design new construction solutions to obtain components that are resistant to abrasive wear and impact.These components are subject to wear during soil cultivation,due to which wear products remain in the soil.In this work,the mass of chemical elements remaining in soil from materials used in selected working parts of agricultural tools intended for soil cultivation was estimated.During the operation of the tested parts,it was found that the following elements were introduced into the soil:Al,B,C,Co,Cr,Cu,Fe,Mo,Nb,Ni,P,Pb,S,Si,Ti,V,Wand Zr.Iron was introduced into the soil in the highest amount(15.907e222.004 g∙ha-1).Among the chemical elements reaching the soil,there were also elements that may pose a toxicological threat.It was found that the mass of chemical elements introduced into the soil depends on their content in the used structural materials and also on the conditions of cultivation,which determine the wear intensity of the parts.展开更多
文摘The Phewa watershed is under constant landslide threat because of its complicated topography,climate,and biology.The floral structure of landslide-prone areas possesses a significant impact on determining the ecological processes involved in slope stabilization.Plant roots,for example,serve as physical anchors in the soil,enhancing slope stability.Therefore,this study aims to determine appropriate plant species that can enhance soil stability in Phewa Watershed by examining their floral structure in landslide areas.Floral diversity was assessed throughout field visits.Ten of the 46 landslides were selected with 15 plots based on aspect,watershed zones,and normalized difference vegetation index(NDVI)value.Six plant species were selected to evaluate root traits,uprooting force,and cellulosic testing based on their Important Value Index(IVI)value,native characteristics,and regeneration.The uprooting force was calculated using a‘winch’with a force transducer,while the root characteristics were measured manually and using‘ImageJ software’.Results show that 319 species from 92 families are registered in the buffer zones and landslide scars,and the NDVI suggest that vegetation covers more than 49%of the landslide areas.The floral composition of the landslides in the 15 plots contains 140 species from 52 families,with Poaceae dominating.In six plant species,the Ochiai index suggests a significant level of association.The uprooting force is correlated to the root diameter and number but is insignificant in terms of root length and area.Saccharum spontaneum is the best option for landslide stability based on uprooting force(882.63±245.175)N,cellulose content(67.038±4.766)%and root number characteristic(69.333±24.338)whereas Themeda arundinacea is preferred due to its root diameter traits(0.054±0.022)cm.Finally,it emphasizes the significance of selecting key species in lowering the risk of landslides,strengthening soil stability,and building resilient ecosystems in susceptible watershed areas.
基金jointly funded by the Thailand Science Research and Innovation (TSRI) and the Electricity Generating Authority of Thailand (EGAT) under grant number RDG60D0002partially supported by the Graduate School,Prince of Songkla University,Thailandsupported by Scholarship Awards Thai PhD students under Thailand’s Education Hub for Southern Region of ASEAN Countries.
文摘Atmospheric nanoparticles(PM<0.1μm)are a major cause of environmental problems and also affect health risk.To control and reduce these problems,sources identification of atmospheric particulates is necessary.Combustion of bituminous coal and biomass includ-ing rubber wood,palm kernel,palm fiber,rice stubble,rice straw,maize residue,sugarcane leaves and sugarcane bagasse,which are considered as sources of air quality problems in many countries,was performed.Emissions of particle-bound chemical components includ-ing organic carbon(OC),elemental carbon(EC),water-soluble ions(NH4^(+),Cl^(-),NO_(3)^(-),SO_(4)^(2-)),elements(Ca,K,Mg,Na)and heavy metals(Cd,Cr,Ni,Pb)were investigated.The results re-vealed that PM<0.1μm from all samples was dominated by the OC component(>50%)with minor contribution from EC(3%-12%).The higher fraction of carbonaceous components was found in the particulates with smaller sizes,and lignin content may relate to concentration of pyrolyzed organic carbon(PyOC)resulting in the differences of OC/EC values.PM emit-ted from burning palm fiber and rice stubble showed high values of OC/EC and also high PyOC.Non-carbonaceous components such as Cl^(-),Cr,Ca,Cd,Ni,Na and Mg may be useful as source indicators,but they did not show any correlation with the size of PM.
基金supported by Prince of Songkla Universitythe Ministry of Higher Education,Science,Research and Innovation,under the Reinventing University Project(No.REV64022)。
文摘In recent times,multiple Unmanned Aerial Vehicles(UAVs)are being widely utilized in several areas of applications such as agriculture,surveillance,disaster management,search and rescue operations.Degree of robustness of applied control schemes determines how accurate a swarm of UAVs accomplish group tasks.Formation and trajectory tracking controllers are required for the swarm of multiple UAVs.Factors like external environmental effects,parametric uncertainties and wind gusts make the controller design process as a challenging task.This article proposes fractional order formation and trajectory tacking controllers for multiple quad-rotors using Super Twisting Sliding Mode Control(STSMC)technique.To compensate the effects of the disturbances due to parametric uncertainties and wind gusts,Lyapunov function based adaptive controllers are formulated.Moreover,Lyapunov theorem is used to guarantee the stability of the proposed controllers.Three types of controllers,namely fixed gain STSMC and fractional order Adaptive Super Twisting Sliding Mode Control(ASTSMC)methods are tested for the swarm of UAVs by performing the numerical simulations in MATLAB/Simulink environment.From the presented results,it is verified that in presence of wind disturbances and parametric uncertainties,the proposed fractional order ASTSMC technique showed improved robustness as compared to the fixed gain STSMC and integer order ASTSMC.
基金Supported by the National Science and Technology Development Agency,Thailand(Research Chair Grant NO.P-10-10307)
文摘Objective: To examine the resurgence rate, house density index(HDI) and parous rate of the Aedes aegypti vector after space spraying carried out by the routine spraying team,and compare with the rates after standard indoor ultra low volume(SID-ULV) spraying carried out by the trained research spraying team.Methods: Between March and September 2014, a cluster randomized controlled trial including 12 clusters(6 regular ULV, 6 SID-ULV) with totally 4 341 households was conducted, and around 20–31 houses in each cluster were selected for assessment. The parous rate and HDI of collected mosquitoes 2 days before and 1, 2 and 6 days after spraying were obtained and compared.Results: The HDI dropped significantly from the baseline 1 and 2 days after spraying to a non-zero value in the SID-ULV treated locations but not in the regular ULV group locations. However, by 6 days after spraying, the HDI of both groups had returned to the base value measured 2 days before spraying. There were no statistically significant differences in the parous rate between groups.Conclusions: SID-ULV is more effective in reducing Aedes aegypti populations.However, rapid resurgence of dengue vector after spraying in urban areas was observed in both groups.
基金financially supported by the Biodiversity-based Economy Development Office of Thailand under grant#ENG6205126S。
文摘Transboundary and domestic aerosol transport during 2018–2019 affecting Bangkok air quality has been investigated.Physicochemical characteristics of size-segregated ambient particles down to nano-particles collected during 2017 non-haze and 2018–2019 haze periods were analyzed.The average PM2.5 concentrations at KU and KMUTNB sites in Bangkok,Thailand during the haze periods were about 4 times higher than in non-haze periods.The highest average organic carbon and elemental carbon concentrations were 4.6±2.1μg/m3 and 1.0±0.4μg/m3,respectively,in PM0.5–1.0 range at KU site.The values of OC/EC and charEC/soot-EC ratios in accumulation mode particles suggested the significant influence of biomass burning,while the nuclei and coarse mode particles were from mixed sources.PAH concentrations during 2018–2019 haze period at KU and KMUTNB were 3.4±0.9 ng/m3 and 1.8±0.2 ng/m3,respectively.The PAH diagnostic ratio of PM2.5 also suggested the main contributions were from biomass combustion.This is supported by the 48-hrs backward trajectory simulation.The higher PM2.5 concentrations during 2018–2019 haze period are also associated with the meteorological conditions that induce thermal inversions and weak winds in the morning and evening.Average values of benzo(a)pyrene toxic equivalency quotient during haze period were about 3–6 times higher than during non-haze period.This should raise a concern of potential human health risk in Bangkok and vicinity exposing to fine and ultrafine particulate matters in addition to regular exposure to traffic emission.
文摘Application of the linear regression between vehicle types/numbers and PAH contents (Particle + Vapor) within a radius of 60 and 300 miles can be employed to assess the impact of long range atmospheric transportation (LRAT) to the level of PAHs in the rural atmosphere of Whitbourne,UK.In general,higher R-values coupled with lower P-values were found in those samples within a radius of 300 miles,whereas lower R-values were detected in those samples within a radius of 60 miles.R-values of PAH concentrations vs.all vehicle numbers within radius of 300 miles ranged from 0.51 to 0.92 with the arithmetic mean of 0.75 ± 0.12,whilst those R-values within a radius of 60 miles ranged from 0.05 to 0.61 with the arithmetic mean of 0.11 ± 0.28.This supports the hypothesis that PAHs in Whitbourne undergo LRAT.
文摘Atmospheric lifetimes and traveling distances of 15 PAHs(Ac:acenaphthylene,Ace:acenaphthene,Ph:phenanthrene,MePh3:3-methyl-phenanthrene,MePh9:9-methyl-phenanthrene,MePh1:1-methyl-phenanthrene,MePh2:2-methyl-phenanthrene,Ret:retene,B[a]A:benzo[a]anthracene,Chry:chrysene,B[b,j,k]F:benzo[b,j,k]fluoranthene,B[e]P:benzo[e]pyrene,B[a]P:benzo[a]pyrene,Ind:indeno[1,2,3-cd]pyrene,B[g,h,i]P:benzo[g,h,i]perylene)at Whitbourne,UK,were estimated by using the rate constants for reaction with OH,O3,and the first order rate constants of eight species of high molecular weight PAHs(i.e.B[a]A,Chry,B[b]F,B[k]F,B[a]P,Ind,B[g,h,i]P and Ret)as a function of humidity,solar intensity and temperature by using Multiple Regression Analysis.The predicted atmospheric lifetime of Ac,Ace,Ph,MePh3,MePh9,MePh2 and MePh1 ranged between 11.42 h-79.12 h in cold period and 1/31 h-14.33 h in warm period respectively.The binary ratios of atmospheric lifetime of B[k]F/B[g,h,i]P,B[k]F/B[g,h,i]P,B[g,h,i]P/Ind and B[k]F/Ind displayed non-significant differences between cold and warm period,indicating that high molecular weight PAHs are difficult to be decomposed by UV light and thus may be conveyed to the rural regions via long range atmospheric transportation(LRAT).The decreased level of the atmospheric lifetime of low molecular weight PAHs in summer can be attributed to an increased level of OH radical content and solar radiation.
文摘<div style="text-align:justify;"> Size-segregated of particulate matter (PM) including PM<sub>0.1</sub> at two different sites, i.e., educational (EA) and residential (RA) areas in Padang city, Indonesia were sampled by using a cascade type air sampler for 24 hours with the average flowrate 40 l/m throughout three weeks (March, 08<sup>th</sup>-25<sup>th</sup> 2018). Carbonaceous components were analyses by a carbon analyzer following the IMPROVE_TOR protocol. Average PM<sub>2.5</sub> and PM<sub>10</sub> concentrations in RA were higher than those in EA while being below the NAAQS of Indonesia. However, it was much higher compared to the WHO limit for 24 hours in RA. OC was the dominant fraction in TC. OC/EC ratio ranging from 2.4 to 33.0 was similar at both sites, suggesting the OC was emitted from various sources. Char-EC and soot-EC ratio were founded to be minimized for PM<sub>0.1</sub> (0.40 ± 0.27 and 0.39 ± 0.39, respectively at each site), indicating a more influence of burning of fossil fuel as vehicles exhaust and coal combustion. The transboundary influence of open biomass burning was not so significant although it cannot be ignored. </div>
基金financially supported by Thailand Science Research and Innovation (TSRI) and Electricity Generating Authority of Thailand (EGAT) under grant number RDG60D0002supported by the Interdisciplinary Graduate School of Energy Systems,Prince of Songkla University via student scholarships under grant number IGS-Energy 1-2018/09Equipment support from the East Asia Nanoparticle Monitoring Network (EA-Nano Net)
文摘Distribution of PM_(0.1),PM_(1) and PM_(2.5) particle-and gas-polycyclic aromatic hydrocarbons(PAHs)during the 2019 normal,partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic risks.PM1 was the predominant component,during partial and strong haze periods,accounting for 45.1% and 52.9% of total suspended particulate matter,respectively,while during normal period the contribution was only 34.0%.PM_(0.1) concentrations,during the strong haze period,were approximately 2 times higher than those during the normal period.Substantially increased levels of particle-PAHs for PM_(0.1),PM_(1) and PM_(2.5) were observed during strong haze period,about 3,5 and 6 times higher than those during normal period.Gas-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM_(2.5).Average total Benzo[a]Pyrene Toxic Equivalency Quotients(BaP-TEQ)in PM_(0.1),PM_(1) and PM_(2.5) during haze periodswere about 2–6 times higher than in the normal period.The total accumulated Incremental Lifetime Cancer Risks(ILCRs)in PM_(0.1),PM_(1) and PM_(2.5) for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in nonhaze scenario,indicating a higher potential carcinogenic risk.These observations suggest PM_(0.1),PM_(1) and PM_(2.5) were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland fires.This leads to an increase in the volume of smoke aerosol,exerting a significant impact on air quality in southern Thailand,as well as many other countries in lower southeast Asia.
基金supported by Research Fund,Prince of Songkla University Contract Number MET590137S.
文摘Objective:To demonstrate the effect of indoor spraying and window screens on Aedes aegypti mosquito density after space spraying.Methods:A total of 141 households(the study houses)in six communities of Songkhla City,located in Songkhla Province of southern Thailand,were randomly selected and the adult Ae.aegypti populations were assessed pre-and post-insecticide spraying from March to October,2014.Houses close to(within a 20 m radius)the study houses were analyzed using spatial analysis tools.The Aedes aegypti density in the study houses and house density index were compared with the density in the neighbouring houses,based on three spraying conditions:(i)unsprayed(ii)only outdoor sprayed and(iii)indoor plus outdoor sprayed.Results:Only spraying houses indoors was the most effective(P<0.05).There was insufficient evidence that the source of the increase in the number of mosquitoes in unsprayed houses was due to their migration from neighbouring houses which had been sprayed.However,the study houses without screens on their windows were found to have a likely higher dengue vector population after spraying,but the difference was not significant.Conclusions:In dengue endemic areas,all houses should be fully screened and the number of houses ultra-low volume sprayed indoor plus outdoor should be increased with the cooperation of householders and communities during epidemics.
基金support from the Faculty of Environmental Management,as well as the High-Potential Talent Fund to strengthen capabilities in the economic,social,and community sectors(Talent Utilization)Type 2 No.TU1-10/2564 from the Graduate School,Prince of Songkla University(PSU)the Southern Industrial Pollutions Research and Warning Center(DIW,Department of Industrial Works)for their invaluable academic guidance,technical resources,and facility support throughout this study.
文摘This article concentrates on the aeration efficiency of venturi air injectors in aquaculture or wastewater treatment.This study was designed to investigate the location of the dissolved oxygen(DO)sensor installation,with a focus on investigating the aeration mechanism by studying ten variables,including temperature,pH,oxidation-reduction potential(ORP),electrical conductivity,resistivity,total dissolved solids,salinity,pressure,dissolved oxygen,and the effect of changing the position of DO sensor installations in different locations via oxygen transfer.The water temperature was raised due to the heating of the water pump.It ranged from 29.7°C to 32.78°C,with different temperatures resulting in different oxygen solubility.The pH level increased with the rise in oxygen levels due to an increase in OH-concentration,whereas the ORP decreased when oxygen levels rose,increasing the reduction reaction.A study on the effect of changing the position of DO sensor installations in different locations was discovered using oxygen transfer coefficients(K_(La))variables.The K_(La)values at nozzle depths of 15 cm,30 cm,and 45 cm were 0.0004±0.0001,0.00042±0.0001,and 0.00136±0.00013,respectively.Therefore,there is a slight difference of K_(La)value when changing the position of sensor installations.An inappropriate distance between the DO sensor and nozzle installation is able to cause turbulent flow.This event resulted in an incorrect DO value.Moreover,the installation of the DO sensor too far from the nozzle resulted in a low value of DO.
基金financially supported by Academic Research Division,The Thailand Research Fund(TRF)(Grant Number TRG5880127)Prince of Songkla University
文摘Disaster risk reduction has become a global strategy for making cities more resilient since the establishment of the Hyogo Framework for Action in 2005. The question that still challenges emergency management scholars and professionals, however, is what contributes to the progress of resilience building. Previous literature suggests that disaster resilience can be attributable to multiple factors, including leadership. But the specific abilities that help leaders promote resilience have not yet been examined empirically. To address this problem, using the United Nations International Strategy for Disaster Reduction 10 Essentials for Making Cities Resilient as guidelines, we assessed the progress of flood resilience building in Thailand and its relationship to local government leaders' abilities. Our research showed that, since the flood disaster in 2011, municipalities in Thailand have made moderate progress in flood resilience building. The results of a multiple regression analysis revealed that disaster resilience leadership abilities have had a statistically significant, positive effect on the progress of flood resilience building. Our findings underscore the role of leadership in making cities more resilient and shed light on how local government leaders can contribute to the progress ofdisaster risk reduction. We also outline the academic implications and practical contributions of our research.
文摘For the manufacture of working parts of agricultural tools operating in soil,various structural materials are used:alloy and low-alloy steels,weld materials for hardfacing,and plates made from cementedcarbide.Manufacturers design new construction solutions to obtain components that are resistant to abrasive wear and impact.These components are subject to wear during soil cultivation,due to which wear products remain in the soil.In this work,the mass of chemical elements remaining in soil from materials used in selected working parts of agricultural tools intended for soil cultivation was estimated.During the operation of the tested parts,it was found that the following elements were introduced into the soil:Al,B,C,Co,Cr,Cu,Fe,Mo,Nb,Ni,P,Pb,S,Si,Ti,V,Wand Zr.Iron was introduced into the soil in the highest amount(15.907e222.004 g∙ha-1).Among the chemical elements reaching the soil,there were also elements that may pose a toxicological threat.It was found that the mass of chemical elements introduced into the soil depends on their content in the used structural materials and also on the conditions of cultivation,which determine the wear intensity of the parts.
