[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, ...[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, and selecting Hainan province as the research target, where the typhoon disaster occurred relatively serious, based on the typhoon data during 1958-2008, with happening frequency of typhoon hazard-formative factors, maximum rainfall, potentially devastating effects of typhoon winds as evaluation indexes, the typhoon disaster risk evaluation index system and evaluation model were established. And by dint of GIS technique, Hainan island typhoon disaster risk zoning of hazard-formative factors and grading were prepared. [Result] Typhoon occurred frequently in Hainan and there were no certain rules of its annual changes. The monthly changes mainly happed during July to October. The highly dangerous area of typhoon mainly distributed in east coast area. The annual daily precipitation decreased from central mountainous area to the surroundings; typhoon hided in the destructive highly risked area in east, south and west area; low disastrous area occurred in the middle area; the risks of disastrous factors weakened from east area to west area. The distribution area of each level was that low dangerous area>mild dangerous area>highly dangerous area>secondary low dangerous area>highly dangerous area. [Conclusion] The study supplied scientific reference for the government in the united organization and direction of disaster relief work.展开更多
The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide ...The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide mass range,high resolution and mass measurement accuracy,high sensitivity and high analysis speed.In this paper,research progresses of TOF-MS on the detection of food additives,food contaminants and residues,illegal additives,pesticide residues,veterinary drug residues and mycotoxin were reviewed,and its probable approaching applications were prospected.展开更多
Tibet is one of the areas with most serious geological hazards in China, and the distribution of disasters has obvious local charac teristics. Tibet can be classified as three parts through zoning the danger degree, t...Tibet is one of the areas with most serious geological hazards in China, and the distribution of disasters has obvious local charac teristics. Tibet can be classified as three parts through zoning the danger degree, the mountain canyon high danger zone of east and southeast Tibet, the plateau mountain lake basin and valley middle danger zone of south Tibet, and the Plateau Mountain lake basin low danger zone of south Tibet. This paper takes the debris flow, collapse, landslide as the key points to analyze the distribution characteristics of geological hazards, and analyze the factors which influence the distribution of geological hazards, such as terrain landform, formation lithology, geologic structure pattern, precipitation, earthquake, human activity and so on. finally, as a conclusion., in whole Tibet, the geological hazards are more in southeast than in northwest, more in mountainous area which in the edge of plateau and river valley than in the interior of plateau and lake basin. And most hazards distribute in the regions where human activity is stronger than in other regions, for example towns or strips along the highway.展开更多
In this paper, the status quo of safety production on construction sites and the hazardous and harmful factors in the construction process were analyzed, and corresponding suggestions were proposed to make up for the ...In this paper, the status quo of safety production on construction sites and the hazardous and harmful factors in the construction process were analyzed, and corresponding suggestions were proposed to make up for the shortcomings of the safety production assurance system standards on construction sites.展开更多
Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM (coal-bed methane) reserves in China, however, due to the unique features of coal seams (i.e., low temperature, strong adsorp...Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM (coal-bed methane) reserves in China, however, due to the unique features of coal seams (i.e., low temperature, strong adsorption and abnormal development of natural fracture systems) as compared with the conventional reservoirs, the fractures propagate is difficult and the risk of damage to coal seam itself and the hydraulic fractures would be extremely high in the course of fracturing. As a result, losses would be suffered on the post-frac production of CBM wells.With the mean of numerical simulation, in this paper, the main factors have impact on the post-frac results as well as the extent to which the impact is brought were researched, and the technical solutions for the improvement of the fracturing performance was put forwards.展开更多
Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been re...Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities.This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei(B-T-H) Region in China.The goal is to replicate and test the applicability of the United States Social Vulnerability Index(So VI) method in a Chinese cultural context.Thirty-nine variables adapted from the So VI were collected in relation to two aspects:socioeconomic vulnerability and built environment vulnerability.Using factor analysis,seven factors were extracted from the variable set:the structure of social development,the level of economic and government financial strength,social justice and poverty,family structure,the intensity of space development,the status of residential housing and transportation,and building structure.Factor scores were summed to get the final So VI scores and the most and least vulnerable units were identified and mapped.The highest social vulnerability is concentrated in the northwest of the study area.The least socially vulnerable areas are mainly distributed in the Beijing,Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities.The results show that this method is a useful tool for revealing places that have a high level of vulnerability,in other words,areas which are more likely to face significant challenges in coping with a large-scale event.These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.展开更多
In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resi...In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure calculations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part 11, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.展开更多
In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resi...In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and non-extreme live loads. Design against earthquake load effect is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based failure calculations. In Part I of this series, the general principle for treating the scour depth as an equivalent load effect is presented. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load effect are quantitatively discussed. The key formulae of the conditional partial failure probabilities and the necessary conditions are established. In order to illustrate the methodology, an example of dead, truck, earthquake and scour effects on a simple bridge pile foundation is represented.展开更多
Landslide hazard and risk assessment on the northern slope of Mt. Changbai, a well-known tourist attraction near the North Korean-Chinese border, are assessed. This study is divided into two parts, namely, landslide h...Landslide hazard and risk assessment on the northern slope of Mt. Changbai, a well-known tourist attraction near the North Korean-Chinese border, are assessed. This study is divided into two parts, namely, landslide hazard zonation and risk assessment. The 1992 Anbalagan and Singh method of landslide hazard zonation (LHZ) was modified and used in this area. In this way, an Associative Analysis Method was used in representative areas to get a measure for controlling factors (slope gradient, relative relief, vegetation, geology, discontinuity development, weak layer thickness and ground water). For the membership degree of factor to slope failure, the middle range of limited values was used to calculate LHZ. Based on an estimation of the potential damage from slope failure, a reasonable risk assessment map was obtained using the relationship of potential damage and probable hazard to aid future planning and prediction and to avert loss of life.展开更多
Early age at first sexual intercourse comes with many negative sexual outcomes namely: having unprotected sex on first sexual intercourse, condom misuse, high rate of sexually transmitted infections (STIs), teenage pr...Early age at first sexual intercourse comes with many negative sexual outcomes namely: having unprotected sex on first sexual intercourse, condom misuse, high rate of sexually transmitted infections (STIs), teenage pregnancy, increased number of sexual partners, etc. In this paper, we considered some socio-demographic and cultural factors and their relationship with age at first sexual intercourse so as to reduce the numerous negative sexual outcomes of early age at first sexual intercourse using the 2018 Nigerian Demographic and Health Survey data. The analysis was made using the Cox proportional hazard model and the Kaplan-Meier plot. The result shows that some respondents started having their first sexual intercourse at the age of 8 years and about 54.4% of the respondents had their first sexual intercourse before age 17 years. The median age of first sexual intercourse is 16 years which implies that about 50% of the respondents had their first sexual intercourse on or before their 16th birthday. Education, religion, region and residence significantly affects the age of first sexual intercourse while circumcision has no significant effect.展开更多
In the U.S., the current Load and Resistance Factor Design (LRFD) Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of...In the U.S., the current Load and Resistance Factor Design (LRFD) Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are on the same reliability-based platform. Since these extreme loads are time variables, combining them with not considered frequent. non- extreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a criterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively,展开更多
The trade situation about China’s export of toy products to the EU was introduced. The recall characteristics of China’s toy products by the EU “Safety Gate” in terms of recall frequency, notified countries, taken...The trade situation about China’s export of toy products to the EU was introduced. The recall characteristics of China’s toy products by the EU “Safety Gate” in terms of recall frequency, notified countries, taken measures, and reasons for recall were analyzed in this paper, and the risk factors of human health of unqualified products in terms of chemical hazards were studied in this paper. It is found that phthalate, boron, plumbum and cadmium were the main factors. Assessment of risk for boron in toys was conducted. It is suggested to limit the boron element in Slime: the limit of migration of boron in Slime toys for 3- to 6-year-old children shall be less than 704 mg/kg, and the limitation of migration of boron in Slime toys for 7- to 12-year-old children shall be less than 1268 mg/kg.展开更多
The seismic intensities, lithologic characteristics and terrain features from a 3000 km2-region near the epicenter of the Lushan earthquake are used to analyze earthquake-induced geological disaster. The preliminary r...The seismic intensities, lithologic characteristics and terrain features from a 3000 km2-region near the epicenter of the Lushan earthquake are used to analyze earthquake-induced geological disaster. The preliminary results indicate that secondary effects of the earthquake will affect specific areas, including those with glutenite and carbonate bedrock, a seismic intensity of IX, slopes between 40° and 50°, elevations of less than 2500 m, slope change rates between 20° and 30°, slope curvatures from - 1 to -0.5 and 0. 5 to 1, and relief between 50 and 100 m. Regions with susceptibility indices greater than 0.71 are prone to landslides and collapses. The secondary features are mainly distributed on both sides of the ridges that extend from Baosheng to Shuangshi and from Baosheng to Longxing. Other features are scattered on both sides of the ridges that extend from Qishuping to Baosheng and from Masangping to Lingguan. The distribution of the earthquake-related features trends in the NE direction, and the area that was most affected by the Lushan earthquake covers approximately 52.4 km^2.展开更多
This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 co...This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 counts of patients, and the goodness-of-fit test confirms a strong fit with a p-value of 0.6196. The PCJ distribution is found to be the best fit based on information criteria (AIC and BIC) with the smallest negative log-likelihood, AIC, and BIC values. The study uses datasets from St. Luke hospital Uyo, Nigeria, containing HIV/AIDS diagnosis date, age, CD4 count, gender, and opportunistic infection dates. Multiple linear regression is employed to analyze the relationship between these variables and HIV/AIDS diagnostic time. The results indicate that age, CD4 count, and opportunistic infection significantly impact the diagnostic time, while gender shows a nonsignificant relationship. The F-test confirms the model's overall significance, indicating the factors are good predictors of HIV/AIDS diagnostic time. The R-squared value of approximately 72% suggests that administering antiretroviral therapy (ART) can improve diagnostic time by suppressing the virus and protecting the immune system. Cox proportional hazard modeling is used to examine the effects of predictor variables on patient survival time. Age and CD4 count are not significant factors in the hazard of HIV/AIDS diagnostic time, while opportunistic infection is a significant predictor with a decreasing effect on the hazard rate. Gender shows a strong but nonsignificant relationship with decreased risk of death. To address the violation of the assumption of proportional hazard, the study employs an assumption-free alternative, Aalen’s model. In the Aalen model, all predictor variables except age and gender are statistically significant in relation to HIV/AIDS diagnostic time. The findings provide valuable insights into the factors influencing diagnostic time and survival of HIV/AIDS patients, which can inform interventions aimed at reducing transmission and improving early diagnosis and treatment. The Power Chris-Jerry distribution proves to be a suitable fit for modeling CD4 counts, while multiple linear regression and survival analysis techniques provide insights into the relationships between predictor variables and diagnostic time. These results contribute to the understanding of HIV/AIDS patient outcomes and can guide public health interventions to enhance early detection, treatment, and care.展开更多
This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 co...This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 counts of patients, and the goodness-of-fit test confirms a strong fit with a p-value of 0.6196. The PCJ distribution is found to be the best fit based on information criteria (AIC and BIC) with the smallest negative log-likelihood, AIC, and BIC values. The study uses datasets from St. Luke hospital Uyo, Nigeria, containing HIV/AIDS diagnosis date, age, CD4 count, gender, and opportunistic infection dates. Multiple linear regression is employed to analyze the relationship between these variables and HIV/AIDS diagnostic time. The results indicate that age, CD4 count, and opportunistic infection significantly impact the diagnostic time, while gender shows a nonsignificant relationship. The F-test confirms the model's overall significance, indicating the factors are good predictors of HIV/AIDS diagnostic time. The R-squared value of approximately 72% suggests that administering antiretroviral therapy (ART) can improve diagnostic time by suppressing the virus and protecting the immune system. Cox proportional hazard modeling is used to examine the effects of predictor variables on patient survival time. Age and CD4 count are not significant factors in the hazard of HIV/AIDS diagnostic time, while opportunistic infection is a significant predictor with a decreasing effect on the hazard rate. Gender shows a strong but nonsignificant relationship with decreased risk of death. To address the violation of the assumption of proportional hazard, the study employs an assumption-free alternative, Aalen’s model. In the Aalen model, all predictor variables except age and gender are statistically significant in relation to HIV/AIDS diagnostic time. The findings provide valuable insights into the factors influencing diagnostic time and survival of HIV/AIDS patients, which can inform interventions aimed at reducing transmission and improving early diagnosis and treatment. The Power Chris-Jerry distribution proves to be a suitable fit for modeling CD4 counts, while multiple linear regression and survival analysis techniques provide insights into the relationships between predictor variables and diagnostic time. These results contribute to the understanding of HIV/AIDS patient outcomes and can guide public health interventions to enhance early detection, treatment, and care.展开更多
基金Supported by Hainan Natural Fund Program (809058)Key Operation Suggestion Program of China Meteorological Bureau " Typhoon Disaster Risk Evaluation and Division"
文摘[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, and selecting Hainan province as the research target, where the typhoon disaster occurred relatively serious, based on the typhoon data during 1958-2008, with happening frequency of typhoon hazard-formative factors, maximum rainfall, potentially devastating effects of typhoon winds as evaluation indexes, the typhoon disaster risk evaluation index system and evaluation model were established. And by dint of GIS technique, Hainan island typhoon disaster risk zoning of hazard-formative factors and grading were prepared. [Result] Typhoon occurred frequently in Hainan and there were no certain rules of its annual changes. The monthly changes mainly happed during July to October. The highly dangerous area of typhoon mainly distributed in east coast area. The annual daily precipitation decreased from central mountainous area to the surroundings; typhoon hided in the destructive highly risked area in east, south and west area; low disastrous area occurred in the middle area; the risks of disastrous factors weakened from east area to west area. The distribution area of each level was that low dangerous area>mild dangerous area>highly dangerous area>secondary low dangerous area>highly dangerous area. [Conclusion] The study supplied scientific reference for the government in the united organization and direction of disaster relief work.
基金Supported by Phase II Modern Agricultural Industry Technology System Innovation Team Construction Project of Hebei Province(HBCT2018120207)Key R&D Projects of Hebei Province(19227516D)Tangshan Institute of Industrial Technology for Functional Agricultural Products(2019TY003b)。
文摘The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide mass range,high resolution and mass measurement accuracy,high sensitivity and high analysis speed.In this paper,research progresses of TOF-MS on the detection of food additives,food contaminants and residues,illegal additives,pesticide residues,veterinary drug residues and mycotoxin were reviewed,and its probable approaching applications were prospected.
文摘Tibet is one of the areas with most serious geological hazards in China, and the distribution of disasters has obvious local charac teristics. Tibet can be classified as three parts through zoning the danger degree, the mountain canyon high danger zone of east and southeast Tibet, the plateau mountain lake basin and valley middle danger zone of south Tibet, and the Plateau Mountain lake basin low danger zone of south Tibet. This paper takes the debris flow, collapse, landslide as the key points to analyze the distribution characteristics of geological hazards, and analyze the factors which influence the distribution of geological hazards, such as terrain landform, formation lithology, geologic structure pattern, precipitation, earthquake, human activity and so on. finally, as a conclusion., in whole Tibet, the geological hazards are more in southeast than in northwest, more in mountainous area which in the edge of plateau and river valley than in the interior of plateau and lake basin. And most hazards distribute in the regions where human activity is stronger than in other regions, for example towns or strips along the highway.
基金Sponsored by Research Fund of Binzhou College(BZXYG1817)Ph.D. Startup Funding Project of Binzhou College(2016Y33)Experimental Technology Funding Project of Binzhou College(BZXYSYXM201816)
文摘In this paper, the status quo of safety production on construction sites and the hazardous and harmful factors in the construction process were analyzed, and corresponding suggestions were proposed to make up for the shortcomings of the safety production assurance system standards on construction sites.
文摘Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM (coal-bed methane) reserves in China, however, due to the unique features of coal seams (i.e., low temperature, strong adsorption and abnormal development of natural fracture systems) as compared with the conventional reservoirs, the fractures propagate is difficult and the risk of damage to coal seam itself and the hydraulic fractures would be extremely high in the course of fracturing. As a result, losses would be suffered on the post-frac production of CBM wells.With the mean of numerical simulation, in this paper, the main factors have impact on the post-frac results as well as the extent to which the impact is brought were researched, and the technical solutions for the improvement of the fracturing performance was put forwards.
基金Under the auspices of National Natural Science Foundation of China(No.41401176,41201550,41201114)New Starting Point of Beijing Union University(No.ZK10201406,ZK10201302)+1 种基金Humanities and Social Science Key Research Base of Zhejiang Province(Applied Economics at Zhejiang Gongshang University)(No.JYTyyjj20130105)Incubation Programme of Great Wall Scholars of Beijing Municipal University&College(No.IDHT20130322)
文摘Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities.This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei(B-T-H) Region in China.The goal is to replicate and test the applicability of the United States Social Vulnerability Index(So VI) method in a Chinese cultural context.Thirty-nine variables adapted from the So VI were collected in relation to two aspects:socioeconomic vulnerability and built environment vulnerability.Using factor analysis,seven factors were extracted from the variable set:the structure of social development,the level of economic and government financial strength,social justice and poverty,family structure,the intensity of space development,the status of residential housing and transportation,and building structure.Factor scores were summed to get the final So VI scores and the most and least vulnerable units were identified and mapped.The highest social vulnerability is concentrated in the northwest of the study area.The least socially vulnerable areas are mainly distributed in the Beijing,Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities.The results show that this method is a useful tool for revealing places that have a high level of vulnerability,in other words,areas which are more likely to face significant challenges in coping with a large-scale event.These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.
基金Federal Highway Administration at the University at Buffalo under Contract No. DTFH61-08-C-00012
文摘In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure calculations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part 11, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.
基金Federal Highway Administration at the University at Buffalo under Contract Number DTFH61-08-C-00012
文摘In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and non-extreme live loads. Design against earthquake load effect is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based failure calculations. In Part I of this series, the general principle for treating the scour depth as an equivalent load effect is presented. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load effect are quantitatively discussed. The key formulae of the conditional partial failure probabilities and the necessary conditions are established. In order to illustrate the methodology, an example of dead, truck, earthquake and scour effects on a simple bridge pile foundation is represented.
文摘Landslide hazard and risk assessment on the northern slope of Mt. Changbai, a well-known tourist attraction near the North Korean-Chinese border, are assessed. This study is divided into two parts, namely, landslide hazard zonation and risk assessment. The 1992 Anbalagan and Singh method of landslide hazard zonation (LHZ) was modified and used in this area. In this way, an Associative Analysis Method was used in representative areas to get a measure for controlling factors (slope gradient, relative relief, vegetation, geology, discontinuity development, weak layer thickness and ground water). For the membership degree of factor to slope failure, the middle range of limited values was used to calculate LHZ. Based on an estimation of the potential damage from slope failure, a reasonable risk assessment map was obtained using the relationship of potential damage and probable hazard to aid future planning and prediction and to avert loss of life.
文摘Early age at first sexual intercourse comes with many negative sexual outcomes namely: having unprotected sex on first sexual intercourse, condom misuse, high rate of sexually transmitted infections (STIs), teenage pregnancy, increased number of sexual partners, etc. In this paper, we considered some socio-demographic and cultural factors and their relationship with age at first sexual intercourse so as to reduce the numerous negative sexual outcomes of early age at first sexual intercourse using the 2018 Nigerian Demographic and Health Survey data. The analysis was made using the Cox proportional hazard model and the Kaplan-Meier plot. The result shows that some respondents started having their first sexual intercourse at the age of 8 years and about 54.4% of the respondents had their first sexual intercourse before age 17 years. The median age of first sexual intercourse is 16 years which implies that about 50% of the respondents had their first sexual intercourse on or before their 16th birthday. Education, religion, region and residence significantly affects the age of first sexual intercourse while circumcision has no significant effect.
基金Federal Highway Administration at the University at Buffalo under Contract No.DTFH61-08-C-00012
文摘In the U.S., the current Load and Resistance Factor Design (LRFD) Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are on the same reliability-based platform. Since these extreme loads are time variables, combining them with not considered frequent. non- extreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a criterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively,
文摘The trade situation about China’s export of toy products to the EU was introduced. The recall characteristics of China’s toy products by the EU “Safety Gate” in terms of recall frequency, notified countries, taken measures, and reasons for recall were analyzed in this paper, and the risk factors of human health of unqualified products in terms of chemical hazards were studied in this paper. It is found that phthalate, boron, plumbum and cadmium were the main factors. Assessment of risk for boron in toys was conducted. It is suggested to limit the boron element in Slime: the limit of migration of boron in Slime toys for 3- to 6-year-old children shall be less than 704 mg/kg, and the limitation of migration of boron in Slime toys for 7- to 12-year-old children shall be less than 1268 mg/kg.
基金supported by the Director Foundation of the Institute of Seismology,China Earthquake Administration(201056076,201116002)
文摘The seismic intensities, lithologic characteristics and terrain features from a 3000 km2-region near the epicenter of the Lushan earthquake are used to analyze earthquake-induced geological disaster. The preliminary results indicate that secondary effects of the earthquake will affect specific areas, including those with glutenite and carbonate bedrock, a seismic intensity of IX, slopes between 40° and 50°, elevations of less than 2500 m, slope change rates between 20° and 30°, slope curvatures from - 1 to -0.5 and 0. 5 to 1, and relief between 50 and 100 m. Regions with susceptibility indices greater than 0.71 are prone to landslides and collapses. The secondary features are mainly distributed on both sides of the ridges that extend from Baosheng to Shuangshi and from Baosheng to Longxing. Other features are scattered on both sides of the ridges that extend from Qishuping to Baosheng and from Masangping to Lingguan. The distribution of the earthquake-related features trends in the NE direction, and the area that was most affected by the Lushan earthquake covers approximately 52.4 km^2.
文摘This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 counts of patients, and the goodness-of-fit test confirms a strong fit with a p-value of 0.6196. The PCJ distribution is found to be the best fit based on information criteria (AIC and BIC) with the smallest negative log-likelihood, AIC, and BIC values. The study uses datasets from St. Luke hospital Uyo, Nigeria, containing HIV/AIDS diagnosis date, age, CD4 count, gender, and opportunistic infection dates. Multiple linear regression is employed to analyze the relationship between these variables and HIV/AIDS diagnostic time. The results indicate that age, CD4 count, and opportunistic infection significantly impact the diagnostic time, while gender shows a nonsignificant relationship. The F-test confirms the model's overall significance, indicating the factors are good predictors of HIV/AIDS diagnostic time. The R-squared value of approximately 72% suggests that administering antiretroviral therapy (ART) can improve diagnostic time by suppressing the virus and protecting the immune system. Cox proportional hazard modeling is used to examine the effects of predictor variables on patient survival time. Age and CD4 count are not significant factors in the hazard of HIV/AIDS diagnostic time, while opportunistic infection is a significant predictor with a decreasing effect on the hazard rate. Gender shows a strong but nonsignificant relationship with decreased risk of death. To address the violation of the assumption of proportional hazard, the study employs an assumption-free alternative, Aalen’s model. In the Aalen model, all predictor variables except age and gender are statistically significant in relation to HIV/AIDS diagnostic time. The findings provide valuable insights into the factors influencing diagnostic time and survival of HIV/AIDS patients, which can inform interventions aimed at reducing transmission and improving early diagnosis and treatment. The Power Chris-Jerry distribution proves to be a suitable fit for modeling CD4 counts, while multiple linear regression and survival analysis techniques provide insights into the relationships between predictor variables and diagnostic time. These results contribute to the understanding of HIV/AIDS patient outcomes and can guide public health interventions to enhance early detection, treatment, and care.
文摘This study investigates the impact of various factors on the lifespan and diagnostic time of HIV/AIDS patients using advanced statistical techniques. The Power Chris-Jerry (PCJ) distribution is applied to model CD4 counts of patients, and the goodness-of-fit test confirms a strong fit with a p-value of 0.6196. The PCJ distribution is found to be the best fit based on information criteria (AIC and BIC) with the smallest negative log-likelihood, AIC, and BIC values. The study uses datasets from St. Luke hospital Uyo, Nigeria, containing HIV/AIDS diagnosis date, age, CD4 count, gender, and opportunistic infection dates. Multiple linear regression is employed to analyze the relationship between these variables and HIV/AIDS diagnostic time. The results indicate that age, CD4 count, and opportunistic infection significantly impact the diagnostic time, while gender shows a nonsignificant relationship. The F-test confirms the model's overall significance, indicating the factors are good predictors of HIV/AIDS diagnostic time. The R-squared value of approximately 72% suggests that administering antiretroviral therapy (ART) can improve diagnostic time by suppressing the virus and protecting the immune system. Cox proportional hazard modeling is used to examine the effects of predictor variables on patient survival time. Age and CD4 count are not significant factors in the hazard of HIV/AIDS diagnostic time, while opportunistic infection is a significant predictor with a decreasing effect on the hazard rate. Gender shows a strong but nonsignificant relationship with decreased risk of death. To address the violation of the assumption of proportional hazard, the study employs an assumption-free alternative, Aalen’s model. In the Aalen model, all predictor variables except age and gender are statistically significant in relation to HIV/AIDS diagnostic time. The findings provide valuable insights into the factors influencing diagnostic time and survival of HIV/AIDS patients, which can inform interventions aimed at reducing transmission and improving early diagnosis and treatment. The Power Chris-Jerry distribution proves to be a suitable fit for modeling CD4 counts, while multiple linear regression and survival analysis techniques provide insights into the relationships between predictor variables and diagnostic time. These results contribute to the understanding of HIV/AIDS patient outcomes and can guide public health interventions to enhance early detection, treatment, and care.