A terminal ballistic analysis of the effects of 7.62 mm × 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study.The findings of an instrumented ballistic testing combin...A terminal ballistic analysis of the effects of 7.62 mm × 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study.The findings of an instrumented ballistic testing combined with 3D advanced numerical simulations performed using the IMPETUS Afea? software yielded the conclusions.The experimental verification proved that slight differences in the pitch-andyaw angles of a projectile upon an impact caused different damage types to the projectile’s core.The residual velocities predicted numerically were close to the experimental values and the calculated core deviations were in satisfactory agreement with the experimental results.An extended matrix of the core deviation angles with combinations of pitch-and-yaw upon impact angles was subsequently built on the basis of the numerical study.The presented experimental and numerical investigation examined thoroughly the influence of the initial pitch and yaw angles on the after-perforation projectile’s performance.展开更多
In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandston...In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)system.Subsequently,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material structure.The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse behavior.Furthermore,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles.The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures.Also,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity.The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life.Ultimately,the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave.展开更多
Interbasin water-transfer schemes provide an engineering solution for reconciling the conflict between water demand and availability.In the context of climate change,which brings great uncertainties to water resource ...Interbasin water-transfer schemes provide an engineering solution for reconciling the conflict between water demand and availability.In the context of climate change,which brings great uncertainties to water resource distribution,interbasin water transfer plays an increasingly important role in the global water–food–energy nexus.However,the transfer of water resources simultaneously changes the hydrological regime and the characteristics of local water bodies,affecting biotic communities accordingly.Compared with high economic and technical inputs water-transfer projects require,the environmental and ecological implications of water-transfer schemes have been inadequately addressed.This work selects the largest water-transfer project in China,the South-to-North Water Diversion(SNWD)Project,to critically review its eco-environmental impacts on donor and recipient basins,as well as on regions along the diversion route.The two operated routes of the SNWD Project represent two typical water diversion approaches:The Middle Route uses an excavated canal,while the East Route connects existent river channels.An overview of the eco-environmental implications of these two routes is valuable for the design and optimization of future water-transfer megaprojects.展开更多
This study aims to analyze how park households perceive the economic,sociocultural,and environmental impacts of ecotourism in Simien Mountain National Park(SMNP),Ethiopia.We combined qualitative and quantitative techn...This study aims to analyze how park households perceive the economic,sociocultural,and environmental impacts of ecotourism in Simien Mountain National Park(SMNP),Ethiopia.We combined qualitative and quantitative techniques for data collection.A sequentially embedded mixed design that gives priority to quantitative data was used.We also employed a multistage sampling technique to select respondents from three districts or woredas,namely Debark,Janamora,and Beyeda woredas.Finally,397 participants were involved in the study from a random selection of three villages from each district or woreda.Data were gathered using a survey questionnaire,interviews,and focus group discussions.Data were analyzed using both descriptive and inferential statistical methods,including means,standard deviations,analysis of variance(ANOVA),and logistic regression models.The findings from a logistic regression analysis revealed that ecotourism participation had a significant relationship with gender(B=1.850,P=0.023),level of education(B=0.238,P=0.032),geographical location(B=0.420,P=0.041),and occupation(B=0.920,P=0.019).This investigation suggested that males and individuals with a higher educational background are more likely to possess optimistic perspectives concerning the impacts of ecotourism.Furthermore,individuals residing in districts relatively near ecotourism destinations,those engaged in tourism-related work,and younger participants were recognized as having optimistic viewpoints regarding the impacts of ecotourism.In conclusion,the study highlighted the need for collaborative efforts among stakeholders to maximize ecotourism’s benefits and minimize negative effects in SMNP.To achieve this,it is recommended that the Ethiopian Wildlife Conservation Agency,the Ministry of Tourism,and local government should work together to develop sustainable tourism plans that enhance local livelihoods and park conditions.Efforts should focus on increasing the participation of females and individuals with lower education levels through training and resource provision.展开更多
Climate change has become a global phenomenon and is adversely affecting agricultural development across the globe.Developing countries like Pakistan where 18.9%of the GDP(gross domestic product)came from the agricult...Climate change has become a global phenomenon and is adversely affecting agricultural development across the globe.Developing countries like Pakistan where 18.9%of the GDP(gross domestic product)came from the agriculture sector and also 42%of the labor force involved in agriculture.They are directly and indirectly affected by climate change due to an increase in the frequency and intensity of climatic extreme events such as floods,droughts and extreme weather events.In this paper,we have focused on the impact of climate change on farm households and their adaptation strategies to cope up the climatic extremes.For this purpose,we have selected farm households by using multistage stratified random sampling from four districts of the Potohar region i.e.Attock,Rawalpindi,Jhelum and Chakwal.These districts were selected by dividing the Potohar region into rain-fed areas.We have employed logistic regression to assess the determinants of adaptation to climate change and its impact.We have also calculated the marginal effect of each independent variable of the logistic regression to measure the immediate rate of change in the model.In order to check the significance of our suggested model,we have used hypothesis testing.展开更多
Drought is the most common of all natural disasters in Kenya, in terms of the large areas covered, populations adversely affected and socio-economic impacts. The Upper Ewaso Ng’iro Basin of Kenya is a drought-prone z...Drought is the most common of all natural disasters in Kenya, in terms of the large areas covered, populations adversely affected and socio-economic impacts. The Upper Ewaso Ng’iro Basin of Kenya is a drought-prone zone, lying on the lee slopes of both Mt. Kenya and Aberdares range. This study sought to determine opinions of communities on drought and its impacts on their livelihoods. Baseline data were collected from published reports and literature reviews augmented with information gathered through interviews with communities and key informants. Field data were collected mainly in the three counties of Laikipia, Isiolo and Meru, utilizing semi-structured questionnaire surveys. A total of 187 respondents were interviewed of which 150 were community members and 37 were policy makers. The typologies of community respondents interviewed included small-scale farmers, large commercial farmers, pastoralists, conservancies, water user associations and conservation groups. It was found that drought is a serious disaster in the Upper Ewaso Ng’iro basin, which has been escalating. Communities experienced negative impacts of drought, with the biggest problem being water scarcity, closely followed by food and fodder shortages and poor incomes from farming. Other problems include spikes in livestock theft, loss of livestock from diseases and shortage of pasture. Conflicts over water and pasture escalate during droughts and crime increases due to lack of on-farm employment opportunities. Since drought events are natural phenomena expected to happen any time, there is need to identify how to improve local capacities in drought preparedness, adaptation and resilience.展开更多
The inefficiency of the aviation industry and the persistent rise in aviation hazards have been linked to weather phenomena.As a result,researchers are looking for better solutions to the problem.The study examined th...The inefficiency of the aviation industry and the persistent rise in aviation hazards have been linked to weather phenomena.As a result,researchers are looking for better solutions to the problem.The study examined the impact of thunderstorms on flight operations at Murtala Mohammed International Airport,Lagos.The data on thunderstorms and flight operations were sourced from Nigerian Meteorological Agency(NiMet)and Nigerian Airspace Management Agency(NAMA)respectively.In order to meet the research target,descriptive statistics(mean,standard deviation,and charts)and inferential statistics(Pearson’s Product Moment Correlation(PPMC)and Regression)were used.The significance level for all inferential analyses was set at 5%(0.05).The study revealed that 77.4%of thunderstorms occurred during the rainy season(April-October)while 22.6%occurred during the dry season(November-March).It also revealed some fluctuating movements of a thunderstorm in the study area.According to the findings,thunderstorms occur most frequently at the airport in June and less frequently in January and December.The study also discovered that thunderstorms at the airport are positively and significantly related to flight delays and cancellations,while the association between flight diversions and thunderstorm occurrence is positive but statistically insignificant.Furthermore,flight delays,flight diversions,and flight cancellations interact positively among themselves.The regression result of the study revealed that a 1%increase in thunderstorm occurrence leads to a 19.4%increase in flight delay,a 7.1%increase in flight cancellation,and a 4.3%increase in flight diversion.As a result,the study presented various regression models that may be utilized to make predictions.The study proposes consistent thunderstorm observation at the airport and steady forecasts using the regression models,based on the findings.However,it further recommends that pilots,air traffic controllers,and meteorologists be trained and retrained so that they can provide better and more efficient services.展开更多
Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions ...Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).展开更多
The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response ...The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response to these problems, the evolution of reliability and failure rate under the influence of environmental factors, failure correlations and economy correlations is analyzed. We assume bogie systems form the EMU train in series. The failure correlation matrix of the bogie systems is modeled. With the lowest total maintenance cost as the optimization objective, a decision-making model for EMU train maintenance is established. A dynamic maintenance strategy is proposed for the model, which can improve maintenance plans efficiently. Artificial bee colony algorithm is applied to further iteratively optimize the threshold parameters in the strategy. The results are calculated and verified by a numerical example. The results show the effectiveness of the maintenance decision model. The dynamic maintenance strategy in this paper is compared with the traditional opportunistic maintenance strategy. The proposed maintenance strategy outperforms the traditional opportunistic maintenance strategy in the numerical example.展开更多
Since the beginning of the 21st century,various crisis events have occurred frequently,inflicting substantial impacts on the tourism sector,which has garnered considerable scholarly and policy attention.Nevertheless,l...Since the beginning of the 21st century,various crisis events have occurred frequently,inflicting substantial impacts on the tourism sector,which has garnered considerable scholarly and policy attention.Nevertheless,limited research has systematically explored tourism resilience at the urban scale,and there is a paucity of studies comparing regional differences in tourism resilience under distinct crisis scenarios and their underlying causes.Thus,this study focuses on the Yangtze River Delta and the Pearl River Delta,employing Martin’s regional economic resilience measurement method.It assesses the tourism resilience of the two regions under the impact of the 2008 financial crisis and the COVID-19 pandemic,subsequently visualizing the data results using ArcGIS software.The study also endeavors to unveil potential causes for disparities in urban tourism resilience.The main conclusions are as follows:Firstly,regions with higher economic development exhibit relatively weaker tourism resilience during economic crises,yet demonstrate comparatively stronger resilience during public crises.Secondly,distinct differentiations exist both between and within the Yangtze River Delta and the Pearl River Delta,primarily stemming from variations such as geographical positioning,tourism resource endowments,and industrial and economic structures,both regionally and within individual cities.Thirdly,the determination of regional tourism resilience is intricate and cannot be restricted to a single dimension;multidimensional indicators better encapsulate the essence of regional tourism resilience.展开更多
In this short review paper, the significant and profound impacts of the Pseudo Amino Acid Composition or PseAAC have been briefly presented with crystal clear convincingness.
In this short review paper, the significant and profound impacts of the 5-steps rule have <span style="mso-bookmark:OLE_LINK2;"><span style="mso-bookmark:OLE_LINK1;"><span lang="...In this short review paper, the significant and profound impacts of the 5-steps rule have <span style="mso-bookmark:OLE_LINK2;"><span style="mso-bookmark:OLE_LINK1;"><span lang="EN-US" style="line-height: 97%;font-family:;" capt",serif;font-size:11pt;"="" pro="" minion="">been briefly recalled with crystal clear convincingness.</span></span></span>展开更多
In this short review paper, the significant and profound impacts of the Chou’s “invariance theorem” have been briefly presented with crystal clear convincingness.
Water storage dams worldwide are ageing, and many will reach the end of their designed lifespan by the middle of the 21st century. Some of these dams will likely need to be removed. While dam construction impacts have...Water storage dams worldwide are ageing, and many will reach the end of their designed lifespan by the middle of the 21st century. Some of these dams will likely need to be removed. While dam construction impacts have been widely discussed, dam removal impacts on society and the economy need to be synthesized and considered in the ageing dams’ decision-making process. This paper summarizes dam removal impacts on the local economy and industry, culture, history and heritage, property value, recreation, aesthetics, and disaster avoidance from identified studies worldwide. It demonstrates that these impacts may vary depending on geography and between developed and developing countries. It concludes that dam removal should consider the co</span><span style="font-family:Verdana;">st, environmental, and the socio-economic impacts while including all</span><span style="font-family:Verdana;"> stakeholders who could be positively and negatively impacted by dam removal.展开更多
Mountain glaciers are highly sensitive to climate change. In this paper, we systematically analyzed and discussed the responses of glaciers to climate change during 1960–2017 in western China by the methods of least ...Mountain glaciers are highly sensitive to climate change. In this paper, we systematically analyzed and discussed the responses of glaciers to climate change during 1960–2017 in western China by the methods of least squares and correlation analysis. Results show that the maximum temperature, minimum temperature, average temperature, and precipitation significantly increased in western China at the rates of 0.32°C/10 a, 0.48°C/10 a, 0.39°C/10 a, and 11.20 mm/10 a, respectively. However, the wind speed, hours of sunshine, snowfall, and snowy days displayed decreasing trends at the rates of –0.53 m/(s·10 a), 3.72 h/10 a, –2.90 mm/10 a, and –0.10 d/10 a, respectively. The annual percentage of glacier area decreased by approximately 0.42%, and the average glacier area decreased by 2.76 km^2/a. Meanwhile, glacial shrinkages were greater in the Altay Mountains, Tanggula Mountains, and Qilian Mountains than in the other mountainous regions. Glacier accumulation decreased while melt volume increased at a rate of 2.7×10~4 m^3/a. The area of melt volume was 1.3 times that of the glacier accumulation area. The glacier mass balance(GMB) decreased substantially at a rate of –14.0 mm/a, whereas the equilibrium line altitude(ELA) showed an increasing trend at a rate of 0.5 mm/a. After 1997, the mass was smaller than –500.0 mm, indicating a huge loss in glaciers. Furthermore, relationships between ELA and GMB and various climatic factors were established. Temperature and precipitation demonstrated a significantly negative correlation, whereas wind speed and snowy days had significantly positive correlations with GMB. Snowy days also exhibited a remarkably negative correlation with ELA. The strong warming trend and less snowy days were thought to be the main factors leading to glacial melting, whereas the increase in precipitation, and reductions of sunshine hours and wind speed might slow glacial melting.展开更多
The impacts of climate change on agriculture are still shadowed with uncertainty.However,climate change is expected to adversely affect Iran's agricultural practices through changes in precipitation,temperature an...The impacts of climate change on agriculture are still shadowed with uncertainty.However,climate change is expected to adversely affect Iran's agricultural practices through changes in precipitation,temperature and carbon dioxide fertilization.Therefore,adaptation of this sector to the increasing weather events is imperative.This study is aimed to document the likely impacts of climate change on Iran's agriculture and the current adaptation efforts made by government and farmers.The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield,crops' water requirements and income and welfare of farm families.The extent of the changes in yield depends on the crop type,assumptions related to the CO_2 fertilization effect,climate scenarios and adaptation abilities.On adaptation,the government's efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology,developing new technologies and policy reforms.Farmers' adaptive responses have also been identified.Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.展开更多
Glacier tourism is an important type of nature-based tourism with great global potential. However, glacial landscapes and environments are seriously affected by global warming. This study used a scoping review method ...Glacier tourism is an important type of nature-based tourism with great global potential. However, glacial landscapes and environments are seriously affected by global warming. This study used a scoping review method to explore integrated impacts of climate change on glaciers from the academic literature. All reviewed literature included a wide range of both research and non-research-based data or information. All literature was reviewed by summarizing findings of relevant research. It showed that climate warming has led to rapid melting and retreat of glacier landscapes, which has resulted in a huge impact on economic and social systems. The findings indicated that some glacial landscapes are declining in aesthetics or attractiveness while some landscapes face the prospect of sustained decline or even disappearance. This not only affects glacial cultural appreciation or mountain residents' beliefs, but increases the difficulty in entering and experiencing glaciers. Some points of tourism even face the risk of glacial disaster. Rapid glacial retreat or even disappearance will bring a loss of tourism revenues. At present, it is urgent to anticipate and adapt to these integrated impacts. In short, this study provides a general review of the impacts of climate change on glacial tourism and also some references for the adaptation of future glacial tourism to climate change.展开更多
This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-...This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-network system (PANS) model guiding the entire study. On the one hand, the HSR projects in the YRD Megaregion are expected to generate significant efficiency-related transportation and non-transportation benefits. As a result, the spillover effects from Shanghai and other major cities (poles) will greatly promote the urban and regional developments along the major HSR corridors (axes), and the entire megaregion will become more integrated economically, socially, and culturally. But, on the other hand, the HSR projects will also create serious social and geographic inequity issues, which need to be addressed as soon as possible in a proper way. This empirical study confirms the PANS model proposed.展开更多
文摘A terminal ballistic analysis of the effects of 7.62 mm × 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study.The findings of an instrumented ballistic testing combined with 3D advanced numerical simulations performed using the IMPETUS Afea? software yielded the conclusions.The experimental verification proved that slight differences in the pitch-andyaw angles of a projectile upon an impact caused different damage types to the projectile’s core.The residual velocities predicted numerically were close to the experimental values and the calculated core deviations were in satisfactory agreement with the experimental results.An extended matrix of the core deviation angles with combinations of pitch-and-yaw upon impact angles was subsequently built on the basis of the numerical study.The presented experimental and numerical investigation examined thoroughly the influence of the initial pitch and yaw angles on the after-perforation projectile’s performance.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.41972283)the Fundamental Research Funds for the Central Universities of Central South University(Grant No.2021zzts0287)the China Scholarship Council(Grant No.202206370109).
文摘In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)system.Subsequently,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material structure.The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse behavior.Furthermore,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles.The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures.Also,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity.The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life.Ultimately,the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave.
基金supported by National Key Science and Technology Program of China(2022YFC3203802)National Natural Science Foundation of China(52121006,92047303,and 51879165)+1 种基金supported by the Xplorer Prizesupported by the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2021QNRC001)。
文摘Interbasin water-transfer schemes provide an engineering solution for reconciling the conflict between water demand and availability.In the context of climate change,which brings great uncertainties to water resource distribution,interbasin water transfer plays an increasingly important role in the global water–food–energy nexus.However,the transfer of water resources simultaneously changes the hydrological regime and the characteristics of local water bodies,affecting biotic communities accordingly.Compared with high economic and technical inputs water-transfer projects require,the environmental and ecological implications of water-transfer schemes have been inadequately addressed.This work selects the largest water-transfer project in China,the South-to-North Water Diversion(SNWD)Project,to critically review its eco-environmental impacts on donor and recipient basins,as well as on regions along the diversion route.The two operated routes of the SNWD Project represent two typical water diversion approaches:The Middle Route uses an excavated canal,while the East Route connects existent river channels.An overview of the eco-environmental implications of these two routes is valuable for the design and optimization of future water-transfer megaprojects.
文摘This study aims to analyze how park households perceive the economic,sociocultural,and environmental impacts of ecotourism in Simien Mountain National Park(SMNP),Ethiopia.We combined qualitative and quantitative techniques for data collection.A sequentially embedded mixed design that gives priority to quantitative data was used.We also employed a multistage sampling technique to select respondents from three districts or woredas,namely Debark,Janamora,and Beyeda woredas.Finally,397 participants were involved in the study from a random selection of three villages from each district or woreda.Data were gathered using a survey questionnaire,interviews,and focus group discussions.Data were analyzed using both descriptive and inferential statistical methods,including means,standard deviations,analysis of variance(ANOVA),and logistic regression models.The findings from a logistic regression analysis revealed that ecotourism participation had a significant relationship with gender(B=1.850,P=0.023),level of education(B=0.238,P=0.032),geographical location(B=0.420,P=0.041),and occupation(B=0.920,P=0.019).This investigation suggested that males and individuals with a higher educational background are more likely to possess optimistic perspectives concerning the impacts of ecotourism.Furthermore,individuals residing in districts relatively near ecotourism destinations,those engaged in tourism-related work,and younger participants were recognized as having optimistic viewpoints regarding the impacts of ecotourism.In conclusion,the study highlighted the need for collaborative efforts among stakeholders to maximize ecotourism’s benefits and minimize negative effects in SMNP.To achieve this,it is recommended that the Ethiopian Wildlife Conservation Agency,the Ministry of Tourism,and local government should work together to develop sustainable tourism plans that enhance local livelihoods and park conditions.Efforts should focus on increasing the participation of females and individuals with lower education levels through training and resource provision.
文摘Climate change has become a global phenomenon and is adversely affecting agricultural development across the globe.Developing countries like Pakistan where 18.9%of the GDP(gross domestic product)came from the agriculture sector and also 42%of the labor force involved in agriculture.They are directly and indirectly affected by climate change due to an increase in the frequency and intensity of climatic extreme events such as floods,droughts and extreme weather events.In this paper,we have focused on the impact of climate change on farm households and their adaptation strategies to cope up the climatic extremes.For this purpose,we have selected farm households by using multistage stratified random sampling from four districts of the Potohar region i.e.Attock,Rawalpindi,Jhelum and Chakwal.These districts were selected by dividing the Potohar region into rain-fed areas.We have employed logistic regression to assess the determinants of adaptation to climate change and its impact.We have also calculated the marginal effect of each independent variable of the logistic regression to measure the immediate rate of change in the model.In order to check the significance of our suggested model,we have used hypothesis testing.
文摘Drought is the most common of all natural disasters in Kenya, in terms of the large areas covered, populations adversely affected and socio-economic impacts. The Upper Ewaso Ng’iro Basin of Kenya is a drought-prone zone, lying on the lee slopes of both Mt. Kenya and Aberdares range. This study sought to determine opinions of communities on drought and its impacts on their livelihoods. Baseline data were collected from published reports and literature reviews augmented with information gathered through interviews with communities and key informants. Field data were collected mainly in the three counties of Laikipia, Isiolo and Meru, utilizing semi-structured questionnaire surveys. A total of 187 respondents were interviewed of which 150 were community members and 37 were policy makers. The typologies of community respondents interviewed included small-scale farmers, large commercial farmers, pastoralists, conservancies, water user associations and conservation groups. It was found that drought is a serious disaster in the Upper Ewaso Ng’iro basin, which has been escalating. Communities experienced negative impacts of drought, with the biggest problem being water scarcity, closely followed by food and fodder shortages and poor incomes from farming. Other problems include spikes in livestock theft, loss of livestock from diseases and shortage of pasture. Conflicts over water and pasture escalate during droughts and crime increases due to lack of on-farm employment opportunities. Since drought events are natural phenomena expected to happen any time, there is need to identify how to improve local capacities in drought preparedness, adaptation and resilience.
文摘The inefficiency of the aviation industry and the persistent rise in aviation hazards have been linked to weather phenomena.As a result,researchers are looking for better solutions to the problem.The study examined the impact of thunderstorms on flight operations at Murtala Mohammed International Airport,Lagos.The data on thunderstorms and flight operations were sourced from Nigerian Meteorological Agency(NiMet)and Nigerian Airspace Management Agency(NAMA)respectively.In order to meet the research target,descriptive statistics(mean,standard deviation,and charts)and inferential statistics(Pearson’s Product Moment Correlation(PPMC)and Regression)were used.The significance level for all inferential analyses was set at 5%(0.05).The study revealed that 77.4%of thunderstorms occurred during the rainy season(April-October)while 22.6%occurred during the dry season(November-March).It also revealed some fluctuating movements of a thunderstorm in the study area.According to the findings,thunderstorms occur most frequently at the airport in June and less frequently in January and December.The study also discovered that thunderstorms at the airport are positively and significantly related to flight delays and cancellations,while the association between flight diversions and thunderstorm occurrence is positive but statistically insignificant.Furthermore,flight delays,flight diversions,and flight cancellations interact positively among themselves.The regression result of the study revealed that a 1%increase in thunderstorm occurrence leads to a 19.4%increase in flight delay,a 7.1%increase in flight cancellation,and a 4.3%increase in flight diversion.As a result,the study presented various regression models that may be utilized to make predictions.The study proposes consistent thunderstorm observation at the airport and steady forecasts using the regression models,based on the findings.However,it further recommends that pilots,air traffic controllers,and meteorologists be trained and retrained so that they can provide better and more efficient services.
基金funded by the National Natural Science Foundation of China(41971038U20A2085+3 种基金32171559U21A2005)the Fundamental Research Funds of CAF(CAFYBB2020QB004CAFYBB2021ZW002)。
文摘Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).
基金Sponsored by the National Natural Science Foundation of China(Grant No. 72061022)。
文摘The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response to these problems, the evolution of reliability and failure rate under the influence of environmental factors, failure correlations and economy correlations is analyzed. We assume bogie systems form the EMU train in series. The failure correlation matrix of the bogie systems is modeled. With the lowest total maintenance cost as the optimization objective, a decision-making model for EMU train maintenance is established. A dynamic maintenance strategy is proposed for the model, which can improve maintenance plans efficiently. Artificial bee colony algorithm is applied to further iteratively optimize the threshold parameters in the strategy. The results are calculated and verified by a numerical example. The results show the effectiveness of the maintenance decision model. The dynamic maintenance strategy in this paper is compared with the traditional opportunistic maintenance strategy. The proposed maintenance strategy outperforms the traditional opportunistic maintenance strategy in the numerical example.
基金funded by National Natural Science Foundation of China,grant number 42271182.
文摘Since the beginning of the 21st century,various crisis events have occurred frequently,inflicting substantial impacts on the tourism sector,which has garnered considerable scholarly and policy attention.Nevertheless,limited research has systematically explored tourism resilience at the urban scale,and there is a paucity of studies comparing regional differences in tourism resilience under distinct crisis scenarios and their underlying causes.Thus,this study focuses on the Yangtze River Delta and the Pearl River Delta,employing Martin’s regional economic resilience measurement method.It assesses the tourism resilience of the two regions under the impact of the 2008 financial crisis and the COVID-19 pandemic,subsequently visualizing the data results using ArcGIS software.The study also endeavors to unveil potential causes for disparities in urban tourism resilience.The main conclusions are as follows:Firstly,regions with higher economic development exhibit relatively weaker tourism resilience during economic crises,yet demonstrate comparatively stronger resilience during public crises.Secondly,distinct differentiations exist both between and within the Yangtze River Delta and the Pearl River Delta,primarily stemming from variations such as geographical positioning,tourism resource endowments,and industrial and economic structures,both regionally and within individual cities.Thirdly,the determination of regional tourism resilience is intricate and cannot be restricted to a single dimension;multidimensional indicators better encapsulate the essence of regional tourism resilience.
文摘In this short review paper, the significant and profound impacts of the Pseudo Amino Acid Composition or PseAAC have been briefly presented with crystal clear convincingness.
文摘In this short review paper, the significant and profound impacts of the 5-steps rule have <span style="mso-bookmark:OLE_LINK2;"><span style="mso-bookmark:OLE_LINK1;"><span lang="EN-US" style="line-height: 97%;font-family:;" capt",serif;font-size:11pt;"="" pro="" minion="">been briefly recalled with crystal clear convincingness.</span></span></span>
文摘In this short review paper, the significant and profound impacts of the Chou’s “invariance theorem” have been briefly presented with crystal clear convincingness.
文摘Water storage dams worldwide are ageing, and many will reach the end of their designed lifespan by the middle of the 21st century. Some of these dams will likely need to be removed. While dam construction impacts have been widely discussed, dam removal impacts on society and the economy need to be synthesized and considered in the ageing dams’ decision-making process. This paper summarizes dam removal impacts on the local economy and industry, culture, history and heritage, property value, recreation, aesthetics, and disaster avoidance from identified studies worldwide. It demonstrates that these impacts may vary depending on geography and between developed and developing countries. It concludes that dam removal should consider the co</span><span style="font-family:Verdana;">st, environmental, and the socio-economic impacts while including all</span><span style="font-family:Verdana;"> stakeholders who could be positively and negatively impacted by dam removal.
基金supported by the National Natural Science Foundation of China (41771048, 41571076)the National Social Science Foundation of China (15XZZ012)+2 种基金the Key Lab Project of Shaanxi Province of China (13JS010)the Baoji University of Arts and Science Project (ZK16061)the Baoji University of Arts and Science Geography Key Discipline Project
文摘Mountain glaciers are highly sensitive to climate change. In this paper, we systematically analyzed and discussed the responses of glaciers to climate change during 1960–2017 in western China by the methods of least squares and correlation analysis. Results show that the maximum temperature, minimum temperature, average temperature, and precipitation significantly increased in western China at the rates of 0.32°C/10 a, 0.48°C/10 a, 0.39°C/10 a, and 11.20 mm/10 a, respectively. However, the wind speed, hours of sunshine, snowfall, and snowy days displayed decreasing trends at the rates of –0.53 m/(s·10 a), 3.72 h/10 a, –2.90 mm/10 a, and –0.10 d/10 a, respectively. The annual percentage of glacier area decreased by approximately 0.42%, and the average glacier area decreased by 2.76 km^2/a. Meanwhile, glacial shrinkages were greater in the Altay Mountains, Tanggula Mountains, and Qilian Mountains than in the other mountainous regions. Glacier accumulation decreased while melt volume increased at a rate of 2.7×10~4 m^3/a. The area of melt volume was 1.3 times that of the glacier accumulation area. The glacier mass balance(GMB) decreased substantially at a rate of –14.0 mm/a, whereas the equilibrium line altitude(ELA) showed an increasing trend at a rate of 0.5 mm/a. After 1997, the mass was smaller than –500.0 mm, indicating a huge loss in glaciers. Furthermore, relationships between ELA and GMB and various climatic factors were established. Temperature and precipitation demonstrated a significantly negative correlation, whereas wind speed and snowy days had significantly positive correlations with GMB. Snowy days also exhibited a remarkably negative correlation with ELA. The strong warming trend and less snowy days were thought to be the main factors leading to glacial melting, whereas the increase in precipitation, and reductions of sunshine hours and wind speed might slow glacial melting.
文摘The impacts of climate change on agriculture are still shadowed with uncertainty.However,climate change is expected to adversely affect Iran's agricultural practices through changes in precipitation,temperature and carbon dioxide fertilization.Therefore,adaptation of this sector to the increasing weather events is imperative.This study is aimed to document the likely impacts of climate change on Iran's agriculture and the current adaptation efforts made by government and farmers.The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield,crops' water requirements and income and welfare of farm families.The extent of the changes in yield depends on the crop type,assumptions related to the CO_2 fertilization effect,climate scenarios and adaptation abilities.On adaptation,the government's efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology,developing new technologies and policy reforms.Farmers' adaptive responses have also been identified.Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.
基金the Major Program of National Natural Science Foundation of China (41690143)the National Natural Science Foundation of China (41701505).
文摘Glacier tourism is an important type of nature-based tourism with great global potential. However, glacial landscapes and environments are seriously affected by global warming. This study used a scoping review method to explore integrated impacts of climate change on glaciers from the academic literature. All reviewed literature included a wide range of both research and non-research-based data or information. All literature was reviewed by summarizing findings of relevant research. It showed that climate warming has led to rapid melting and retreat of glacier landscapes, which has resulted in a huge impact on economic and social systems. The findings indicated that some glacial landscapes are declining in aesthetics or attractiveness while some landscapes face the prospect of sustained decline or even disappearance. This not only affects glacial cultural appreciation or mountain residents' beliefs, but increases the difficulty in entering and experiencing glaciers. Some points of tourism even face the risk of glacial disaster. Rapid glacial retreat or even disappearance will bring a loss of tourism revenues. At present, it is urgent to anticipate and adapt to these integrated impacts. In short, this study provides a general review of the impacts of climate change on glacial tourism and also some references for the adaptation of future glacial tourism to climate change.
文摘This paper assesses the impacts of high speed rail (HSR) development in the Yangtze River Delta (YRD) Megaregion, China. After giving an introduction and conducting a literature review, the paper proposes a pole-axis-network system (PANS) model guiding the entire study. On the one hand, the HSR projects in the YRD Megaregion are expected to generate significant efficiency-related transportation and non-transportation benefits. As a result, the spillover effects from Shanghai and other major cities (poles) will greatly promote the urban and regional developments along the major HSR corridors (axes), and the entire megaregion will become more integrated economically, socially, and culturally. But, on the other hand, the HSR projects will also create serious social and geographic inequity issues, which need to be addressed as soon as possible in a proper way. This empirical study confirms the PANS model proposed.
