Analysis of the dynamic response of a three-dimensional arch dam is conducted taking into account... more Analysis of the dynamic response of a three-dimensional arch dam is conducted taking into account the effects of dam-reservoir and dam-foundation interactions. The Karaj arch-dam in Iran is considered as a case study. The dam, fluid, and foundation domains are treated as substructures and modeled with boundary elements. The foundation domain is assumed to be layered and infinite. This study focuses on the effect of geotechnical conditions on the dynamic response of the dam to harmonic P and S waves. Latest investigations show that the foundation flexibility leads to a reduction in the response through radiation of energy. In this research, it is shown that the effect of soil layers may cause amplification of response in some frequency ranges. This study emphasizes the necessity of comprehensive modeling for site effects to resolve such problems. Also, by identifying the bands of excitation frequencies to which the dam may be more sensitive, it helps in the selection of the most crit...
Journal of Seismology and Earthquake Engineering, 2011
Metropolitan Tehran, as the capital, the economic and political center, and the most populated ci... more Metropolitan Tehran, as the capital, the economic and political center, and the most populated city in Iran, has a special position in earthquake preparation, mitigation and response. Tehran is vulnerable to earthquakes and is expecting a destructive earthquake with a magnitude greater than 7. In the present paper, the items of hazard analysis, vulnerability assessment, and loss estimation in respect of Tehran are introduced, and the relevant research concerning the category of physical and structural damage is investigated. The results from vulnerability assessment indicate the vulnerability of a major part of the buildings in Tehran. The results from the loss estimation indicate a high percentage of damage in the event of an earthquake in Tehran. Furthermore, based on the loss estimation results, the likely amount of debris generated and possibilities for positioning of the temporary housing are provided. The results emphasize the necessity of short-term, average-term and long-ter...
INTRODUCTION: Drought is considered as a complex and creeping natural hazard associated with perv... more INTRODUCTION: Drought is considered as a complex and creeping natural hazard associated with pervasive socio-economic and environmental impacts. Given the water reserves, per capita consumption, and average rainfall, Iran can be regarded as one of the countries facing the risk of lack of physical water resources and therefore proper management of drought in the country is an important issue. The main objective in the present study was to identify the dimensions gaining less attention in the context of executive drought management measures. METHODS: This was an applied-developmental study performed with the field method along with documentary studies. The data collection tool and method, and data analysis method were a researcher-made questionnaire, structured interview, and Q methodology using factor analysis, respectively. The statistical population of the study consisted of 12 executives of the Forests Range and Watershed Management Organization, Deputy ABFA of Ministry of Energy,...
Multivariate statistical techniques and geostatistical methods are among the important tools used... more Multivariate statistical techniques and geostatistical methods are among the important tools used in surface water quality management. They are widely used in interpreting data, identifying the pollution sources, understanding the spatial variation of parameters, and determining the places of monitoring stations. Therefore, in this study, spatial variation of water quality and pollutants in the Anzali Wetland water (Iran) was evaluated using multivariate statistical and Kriging methods. The values of different water quality parameters measured in six stations in the wetland water were subjected to cluster analysis (CA) and principal component analysis (PCA). Cluster analysis reduced the number of stations from six to four. The results of PCA showed that industrial and agricultural pollution sources could be responsible for the Anzali Wetland water quality. Then, the spatial variation maps of the PCA scores were generated using Kriging geostatistical method in the geographical information system (GIS) to investigate the pollution sources affecting the wetland parts. These maps illustrated that a great part of the wetland body was under the effect of agricultural sources, while the industrial sources affected the outlet and central parts. Finally, a comparison between two models (multiple linear regression (MLR) and Kriging) was made to assess their ability in predicting water quality parameters in the study area. The results showed the improvement of prediction using MLR, which was by 25%–97%, compared with Kriging. The results of the present study can be effectively used in the planning and implementation of future monitoring networks in the Anzali Wetland and other similar aquatic systems.
Due to the development of urban areas, underground structures are increasingly needed. Therefore,... more Due to the development of urban areas, underground structures are increasingly needed. Therefore, not only it is likely to have two tunnels located close to each other, but also it happens frequently. Because of the complexity of realistic problems, closed form analytical ...
The influence of experimental factors in solvent extraction for hydrocarbon recovery from oil slu... more The influence of experimental factors in solvent extraction for hydrocarbon recovery from oil sludge was investigated using an orthogonal experimental design. The results indicated that temperature, solvent type, solvent blend, solvent to sludge ratio, and treatment duration had significant effects on hydrocarbon recovery. In this investigation, a response surface methodology used to optimize the conditions required to recover hydrocarbons from oily sludge. In addition, the effectiveness of solvent extraction using solvent blends of methyl ethyl ketone (MEK) and xylene for recovery and upgrading of oily sludge has been determined. Oily sludge used here consisted of 63% of its weight petroleum hydrocarbons. Based on the experimental data, a full quadratic model was generated. Optimization of influential parameters was conducted through the fitted model. As determined by the fitted model, the factors such as temperature, mixing time, MEK, and xylene to sludge ratios for optimum oil sludge recovery with solvent extraction method must be fixed at 49.28 °C, 22 min, 6.04 to 1, and 6.4 to 1, respectively. Under the optimum conditions, 64.04% extraction yield achieved using solvent blends of MEK and xylene according to the model. Using the combination of MEK and xylene for recovery of oil sludge, a maximum extraction yield of 61.44% as petroleum hydrocarbons obtained during experiments. Based on the results, combination of MEK and xylene as solvent blend demonstrated significant effect on hydrocarbon recovery in 6 to 1 and higher ratios.
Different models have been proposed for disaster management by researchers and agencies. Despite ... more Different models have been proposed for disaster management by researchers and agencies. Despite their efficiency in some locations, disasters are still a fundamental challenge in the way of sustainable development. The purpose of this research is developing a comprehensive conceptual model for disaster management using thematic analysis. In this regard, first, disaster management models are collected. In the next stage, the themes of each model are extracted and categorised in three phases. In the first phase that is descriptive coding, available elements in each model are extracted as code and the basic themes are recognised. Then, in the phase of interpretive coding, basic themes are classified in three categories that are called organising themes (i.e. hazard assessment, risk management and management actions). In the final phase, strategic management is selected as the global or overarching theme to integrate all the other themes. Based on thematic analysis, it can be concluded...
The main purpose of this study is to develop a Geospatial Information System (GIS) model with the... more The main purpose of this study is to develop a Geospatial Information System (GIS) model with the ability to assess the seismic damage to pipelines for two well-known hazards, including ground shaking and ground failure simultaneously. The model that is developed and used in this study includes four main parts of database implementation, seismic hazard analysis, vulnerability assessment and seismic damage assessment to determine the pipeline's damage probability. This model was implemented for main water distribution pipelines of Iran and tested for two different earthquake scenarios. The final damage probability of pipelines was estimated to be about 74% for water distribution pipelines of Mashhad including 40% and 34% for leak and break, respectively. In the next step, the impact of each earthquake input parameter on this model was extracted, and each of the three parameters had a huge impact on changing the results of pipelines' damage probability. Finally, the dependency of the model in liquefaction susceptibility, landslide susceptibility, vulnerability functions and segment length was checked out and specified that the model is sensitive just to liquefaction susceptibility and vulnerability functions.
Objective Research on the disaster management plans of renowned universities worldwide shows that... more Objective Research on the disaster management plans of renowned universities worldwide shows that such plans are generally compiled in 3 categories: structural, nonstructural, and organizational sections. The importance of earthquakes in Tehran and the high vulnerability of the University of Tehran to earthquakes encouraged us to challenge the university’s plans concerning disaster management. Methods An initial attempt was made to analyze the disaster management of 23 renowned universities worldwide and their structure compared with the present organizational structure of the University of Tehran. Then an expert opinion study was done to determine the appropriate management structure of the Incident Command System. Results These efforts resulted in an adhocratic system as the proper one for emergency situations after an earthquake. Furthermore, the results of the comparative study led to a general management structure that may be considered as a global pattern. Conclusions An appro...
This paper reviews the efforts of the affected population to cope with the deficiencies in the co... more This paper reviews the efforts of the affected population to cope with the deficiencies in the common temporary shelter solution-the tent. After a brief review of the theoretical framework, common solutions for temporary shelter after disaster are reviewed in past earthquakes. Examples include earthquakes in Italy (1968-1980), Japan (Kobe 1995), and Iran (Gilan and Zanjan, 1980). The paper then reviews field observations in Lorestan Earthquake (2006). In this earthquake, tents were provided as temporary shelter after disaster. The deficiencies of this form of shelter range from environmental comfort to social problems. To solve these problems, the affected community provided many innovative solutions which can be used in similar situations.
Due to Iran's position in a seismic-prone region, the county is always at risk of earthquakes... more Due to Iran's position in a seismic-prone region, the county is always at risk of earthquakes with potentially catastrophic results. Given earthquakes' potential for devastation, hospitals are among the main critical facilities that should be active continuously after an earthquake in order to provide necessary emergency services. In order to access the sufficiency of hospital services after an earthquake, and to reduce potential casualties due to subsequent effects, it is necessary to evaluate both structural and non-structural damage. In this article, methods of damage evaluation applicable to hospitals are reviewed and a summary of hospital damage that has been observed from previous earthquakes is provided. It concludes by proposing a new structure to support the continuity of hospital operations after an earthquake. This new approach is a framework for damage evaluation of hospitals including objectives, responsibilities, action time and operational criteria that covers...
A coupled boundary element method (BEM)-finite element method (FEM) is presented to study the dyn... more A coupled boundary element method (BEM)-finite element method (FEM) is presented to study the dynamic response of tunnels in time domain. A standard boundary element methodology for dynamic analysis of a tunnel in semi-infinite or infinite medium (when the distance to the surface is very high) with direct integration in time domain is coupled to the FEM through a staggered solution approach. Each method provides initial conditions to the other at the beginning of each time step. Formulation and computational aspects of the proposed coupling scheme are discussed. The formulation may be used to study the wave field or the response of models to various kinds of applied loads. The hybrid method exploits the versatility of the FEM for modelling the lining of tunnel and the scatter and the effectiveness of the boundary integral equation method for taking care of the radiation condition in the half space. A numerical example is presented for the validation and demonstration of the general ...
Analysis of the dynamic response of a three-dimensional arch dam is conducted taking into account... more Analysis of the dynamic response of a three-dimensional arch dam is conducted taking into account the effects of dam-reservoir and dam-foundation interactions. The Karaj arch-dam in Iran is considered as a case study. The dam, fluid, and foundation domains are treated as substructures and modeled with boundary elements. The foundation domain is assumed to be layered and infinite. This study focuses on the effect of geotechnical conditions on the dynamic response of the dam to harmonic P and S waves. Latest investigations show that the foundation flexibility leads to a reduction in the response through radiation of energy. In this research, it is shown that the effect of soil layers may cause amplification of response in some frequency ranges. This study emphasizes the necessity of comprehensive modeling for site effects to resolve such problems. Also, by identifying the bands of excitation frequencies to which the dam may be more sensitive, it helps in the selection of the most crit...
Journal of Seismology and Earthquake Engineering, 2011
Metropolitan Tehran, as the capital, the economic and political center, and the most populated ci... more Metropolitan Tehran, as the capital, the economic and political center, and the most populated city in Iran, has a special position in earthquake preparation, mitigation and response. Tehran is vulnerable to earthquakes and is expecting a destructive earthquake with a magnitude greater than 7. In the present paper, the items of hazard analysis, vulnerability assessment, and loss estimation in respect of Tehran are introduced, and the relevant research concerning the category of physical and structural damage is investigated. The results from vulnerability assessment indicate the vulnerability of a major part of the buildings in Tehran. The results from the loss estimation indicate a high percentage of damage in the event of an earthquake in Tehran. Furthermore, based on the loss estimation results, the likely amount of debris generated and possibilities for positioning of the temporary housing are provided. The results emphasize the necessity of short-term, average-term and long-ter...
INTRODUCTION: Drought is considered as a complex and creeping natural hazard associated with perv... more INTRODUCTION: Drought is considered as a complex and creeping natural hazard associated with pervasive socio-economic and environmental impacts. Given the water reserves, per capita consumption, and average rainfall, Iran can be regarded as one of the countries facing the risk of lack of physical water resources and therefore proper management of drought in the country is an important issue. The main objective in the present study was to identify the dimensions gaining less attention in the context of executive drought management measures. METHODS: This was an applied-developmental study performed with the field method along with documentary studies. The data collection tool and method, and data analysis method were a researcher-made questionnaire, structured interview, and Q methodology using factor analysis, respectively. The statistical population of the study consisted of 12 executives of the Forests Range and Watershed Management Organization, Deputy ABFA of Ministry of Energy,...
Multivariate statistical techniques and geostatistical methods are among the important tools used... more Multivariate statistical techniques and geostatistical methods are among the important tools used in surface water quality management. They are widely used in interpreting data, identifying the pollution sources, understanding the spatial variation of parameters, and determining the places of monitoring stations. Therefore, in this study, spatial variation of water quality and pollutants in the Anzali Wetland water (Iran) was evaluated using multivariate statistical and Kriging methods. The values of different water quality parameters measured in six stations in the wetland water were subjected to cluster analysis (CA) and principal component analysis (PCA). Cluster analysis reduced the number of stations from six to four. The results of PCA showed that industrial and agricultural pollution sources could be responsible for the Anzali Wetland water quality. Then, the spatial variation maps of the PCA scores were generated using Kriging geostatistical method in the geographical information system (GIS) to investigate the pollution sources affecting the wetland parts. These maps illustrated that a great part of the wetland body was under the effect of agricultural sources, while the industrial sources affected the outlet and central parts. Finally, a comparison between two models (multiple linear regression (MLR) and Kriging) was made to assess their ability in predicting water quality parameters in the study area. The results showed the improvement of prediction using MLR, which was by 25%–97%, compared with Kriging. The results of the present study can be effectively used in the planning and implementation of future monitoring networks in the Anzali Wetland and other similar aquatic systems.
Due to the development of urban areas, underground structures are increasingly needed. Therefore,... more Due to the development of urban areas, underground structures are increasingly needed. Therefore, not only it is likely to have two tunnels located close to each other, but also it happens frequently. Because of the complexity of realistic problems, closed form analytical ...
The influence of experimental factors in solvent extraction for hydrocarbon recovery from oil slu... more The influence of experimental factors in solvent extraction for hydrocarbon recovery from oil sludge was investigated using an orthogonal experimental design. The results indicated that temperature, solvent type, solvent blend, solvent to sludge ratio, and treatment duration had significant effects on hydrocarbon recovery. In this investigation, a response surface methodology used to optimize the conditions required to recover hydrocarbons from oily sludge. In addition, the effectiveness of solvent extraction using solvent blends of methyl ethyl ketone (MEK) and xylene for recovery and upgrading of oily sludge has been determined. Oily sludge used here consisted of 63% of its weight petroleum hydrocarbons. Based on the experimental data, a full quadratic model was generated. Optimization of influential parameters was conducted through the fitted model. As determined by the fitted model, the factors such as temperature, mixing time, MEK, and xylene to sludge ratios for optimum oil sludge recovery with solvent extraction method must be fixed at 49.28 °C, 22 min, 6.04 to 1, and 6.4 to 1, respectively. Under the optimum conditions, 64.04% extraction yield achieved using solvent blends of MEK and xylene according to the model. Using the combination of MEK and xylene for recovery of oil sludge, a maximum extraction yield of 61.44% as petroleum hydrocarbons obtained during experiments. Based on the results, combination of MEK and xylene as solvent blend demonstrated significant effect on hydrocarbon recovery in 6 to 1 and higher ratios.
Different models have been proposed for disaster management by researchers and agencies. Despite ... more Different models have been proposed for disaster management by researchers and agencies. Despite their efficiency in some locations, disasters are still a fundamental challenge in the way of sustainable development. The purpose of this research is developing a comprehensive conceptual model for disaster management using thematic analysis. In this regard, first, disaster management models are collected. In the next stage, the themes of each model are extracted and categorised in three phases. In the first phase that is descriptive coding, available elements in each model are extracted as code and the basic themes are recognised. Then, in the phase of interpretive coding, basic themes are classified in three categories that are called organising themes (i.e. hazard assessment, risk management and management actions). In the final phase, strategic management is selected as the global or overarching theme to integrate all the other themes. Based on thematic analysis, it can be concluded...
The main purpose of this study is to develop a Geospatial Information System (GIS) model with the... more The main purpose of this study is to develop a Geospatial Information System (GIS) model with the ability to assess the seismic damage to pipelines for two well-known hazards, including ground shaking and ground failure simultaneously. The model that is developed and used in this study includes four main parts of database implementation, seismic hazard analysis, vulnerability assessment and seismic damage assessment to determine the pipeline's damage probability. This model was implemented for main water distribution pipelines of Iran and tested for two different earthquake scenarios. The final damage probability of pipelines was estimated to be about 74% for water distribution pipelines of Mashhad including 40% and 34% for leak and break, respectively. In the next step, the impact of each earthquake input parameter on this model was extracted, and each of the three parameters had a huge impact on changing the results of pipelines' damage probability. Finally, the dependency of the model in liquefaction susceptibility, landslide susceptibility, vulnerability functions and segment length was checked out and specified that the model is sensitive just to liquefaction susceptibility and vulnerability functions.
Objective Research on the disaster management plans of renowned universities worldwide shows that... more Objective Research on the disaster management plans of renowned universities worldwide shows that such plans are generally compiled in 3 categories: structural, nonstructural, and organizational sections. The importance of earthquakes in Tehran and the high vulnerability of the University of Tehran to earthquakes encouraged us to challenge the university’s plans concerning disaster management. Methods An initial attempt was made to analyze the disaster management of 23 renowned universities worldwide and their structure compared with the present organizational structure of the University of Tehran. Then an expert opinion study was done to determine the appropriate management structure of the Incident Command System. Results These efforts resulted in an adhocratic system as the proper one for emergency situations after an earthquake. Furthermore, the results of the comparative study led to a general management structure that may be considered as a global pattern. Conclusions An appro...
This paper reviews the efforts of the affected population to cope with the deficiencies in the co... more This paper reviews the efforts of the affected population to cope with the deficiencies in the common temporary shelter solution-the tent. After a brief review of the theoretical framework, common solutions for temporary shelter after disaster are reviewed in past earthquakes. Examples include earthquakes in Italy (1968-1980), Japan (Kobe 1995), and Iran (Gilan and Zanjan, 1980). The paper then reviews field observations in Lorestan Earthquake (2006). In this earthquake, tents were provided as temporary shelter after disaster. The deficiencies of this form of shelter range from environmental comfort to social problems. To solve these problems, the affected community provided many innovative solutions which can be used in similar situations.
Due to Iran's position in a seismic-prone region, the county is always at risk of earthquakes... more Due to Iran's position in a seismic-prone region, the county is always at risk of earthquakes with potentially catastrophic results. Given earthquakes' potential for devastation, hospitals are among the main critical facilities that should be active continuously after an earthquake in order to provide necessary emergency services. In order to access the sufficiency of hospital services after an earthquake, and to reduce potential casualties due to subsequent effects, it is necessary to evaluate both structural and non-structural damage. In this article, methods of damage evaluation applicable to hospitals are reviewed and a summary of hospital damage that has been observed from previous earthquakes is provided. It concludes by proposing a new structure to support the continuity of hospital operations after an earthquake. This new approach is a framework for damage evaluation of hospitals including objectives, responsibilities, action time and operational criteria that covers...
A coupled boundary element method (BEM)-finite element method (FEM) is presented to study the dyn... more A coupled boundary element method (BEM)-finite element method (FEM) is presented to study the dynamic response of tunnels in time domain. A standard boundary element methodology for dynamic analysis of a tunnel in semi-infinite or infinite medium (when the distance to the surface is very high) with direct integration in time domain is coupled to the FEM through a staggered solution approach. Each method provides initial conditions to the other at the beginning of each time step. Formulation and computational aspects of the proposed coupling scheme are discussed. The formulation may be used to study the wave field or the response of models to various kinds of applied loads. The hybrid method exploits the versatility of the FEM for modelling the lining of tunnel and the scatter and the effectiveness of the boundary integral equation method for taking care of the radiation condition in the half space. A numerical example is presented for the validation and demonstration of the general ...
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Papers by Babak Omidvar