The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
P. W. Haines - One of the best experts on this subject based on the ideXlab platform.
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Tsunami(?) Deposit of Terminal Eocene Age, South Australia: The Inferred Effects of a Low-Angle Multiple Impact Event
2001Co-Authors: P. W. HainesAbstract:Introduction: The author has recently reported the discovery of two new impact Structures near Adelaide in South Australia [1]. Both sites exhibit shock metamorphism and include an 8.5km long elongate crater (Crawford), interpreted as the product of a very lowangle NNE-directed grazing impact, and a Nearby Structure considered to be of secondary origin (Flaxman), resulting from down-range ricochet of part of the projectile. These sites form part of an extensive (230x30km) NNE-trending corridor of similar elongate features and breccia zones (Fig. 1). The corridor cuts obliquely across regional structural, stratigraphic and geophysical trends and defies conventional geological explanations. Although definitive shock metamorphism has yet to be discovered at the other Structures, it has been hypothesised that the corridor is the consequence of a multiple low-angle impact event of substantial magnitude [1], resembling a scaled-up version of the Rio Cuarto crater field in Argentina [2]. The southern limit of the exposed corridor coincides with the shore of the Southern Ocean (on Kangaroo Island) and it is speculated here that the entire putative crater field may comprise secondaries from a single large grazing impact into the Southern Ocean south of Australia.
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tsunami deposit of terminal eocene age south australia the inferred effects of a low angle multiple impact event
caev, 2001Co-Authors: P. W. HainesAbstract:Introduction: The author has recently reported the discovery of two new impact Structures near Adelaide in South Australia [1]. Both sites exhibit shock metamorphism and include an 8.5km long elongate crater (Crawford), interpreted as the product of a very lowangle NNE-directed grazing impact, and a Nearby Structure considered to be of secondary origin (Flaxman), resulting from down-range ricochet of part of the projectile. These sites form part of an extensive (230x30km) NNE-trending corridor of similar elongate features and breccia zones (Fig. 1). The corridor cuts obliquely across regional structural, stratigraphic and geophysical trends and defies conventional geological explanations. Although definitive shock metamorphism has yet to be discovered at the other Structures, it has been hypothesised that the corridor is the consequence of a multiple low-angle impact event of substantial magnitude [1], resembling a scaled-up version of the Rio Cuarto crater field in Argentina [2]. The southern limit of the exposed corridor coincides with the shore of the Southern Ocean (on Kangaroo Island) and it is speculated here that the entire putative crater field may comprise secondaries from a single large grazing impact into the Southern Ocean south of Australia.
Hong Hao - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of structural response and damage to simultaneous ground shock and airblast loads
International Journal of Impact Engineering, 2007Co-Authors: Hong HaoAbstract:Current practice in analysis and design of Structures to withhold surface explosions considers only airblast forces on Structures. A surface explosion, in fact, generates both ground shock and airblast pressure on a Nearby Structure. In this paper, the influences of simultaneous ground shock and airblast forces on structural responses are investigated. Blast-induced surface ground motions and airblast pressures estimated in a previous study are employed as input in the analysis. A previously developed three-dimensional homogenized material model for a masonry wall including the equivalent elastic properties, strength envelope and damage threshold is used to model masonry wall. Another material damage model developed for reinforced concrete Structures is used for modelling RC behavior due to explosive loads. These material models are programmed and linked to an available computer program LS-DYNA3D through its user subroutine capability. A one-story masonry infilled RC frame is used as an example in the study. Dynamic response and damage of the example Structure to simultaneous ground shock and airblast forces, or separately to ground shock only or airblast forces only are calculated. It is found that in general, airblast load governs structural response and damage when the scaled distance is small. However, under certain conditions, structural damage will be critically underestimated if ground shock is neglected. When the scale distance increases, the relative importance of the ground shock on Structure response increases, and ground shock will dominate the surface explosion effects on Structures at large scaled distance. At large scaled distance, the ground shock and airblast force effects on Structures decoupled and Structure response and damage to ground shock and airblast force can be analyzed separately.
Emad Kandil - One of the best experts on this subject based on the ideXlab platform.
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Risk of Intraoperative Injury of Nearby Structures: National Trend, Distribution, and Burden
Journal of the American College of Surgeons, 2016Co-Authors: Zaid Al-qurayshi, Sudesh Srivastav, Douglas P. Slakey, Emad KandilAbstract:Background Accidental injury of a Nearby Structure during surgical operations carries a risk of serious morbidity and mortality. Furthermore, it represents a medico-legal liability. We aimed to examine the national distribution, cost, and trend of accidental intraoperative injuries. Study design We performed a cross-sectional study using the Nationwide Inpatient Sample database. The study population consisted of patients who encountered intraoperative injuries between 2003 and 2010. Controls were randomly selected from patients who underwent similar procedures during the same period. Cost was adjusted for inflation rate to reflect 2015 dollar values. Results A total of 61,667 cases with intraoperative injuries and 430,424 controls were included. Intraoperative injuries were most common in procedures that involved the digestive system (38.0%), female reproductive organs (21.4%), and musculoskeletal system (12.2%). There was a significant increase in those injuries from 161.3 cases/100,000 procedures in 2003 to 254.9 cases/100,000 procedures in 2010 (p Conclusions Certain demographic and clinical factors influence the risk of intraoperative injury of Nearby Structures. The prevalence of intraoperative injuries is increasing at the national level, and these injuries are associated with increased mortality and pose substantial clinical and financial burdens.
Zaid Al-qurayshi - One of the best experts on this subject based on the ideXlab platform.
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Risk of Intraoperative Injury of Nearby Structures: National Trend, Distribution, and Burden
Journal of the American College of Surgeons, 2016Co-Authors: Zaid Al-qurayshi, Sudesh Srivastav, Douglas P. Slakey, Emad KandilAbstract:Background Accidental injury of a Nearby Structure during surgical operations carries a risk of serious morbidity and mortality. Furthermore, it represents a medico-legal liability. We aimed to examine the national distribution, cost, and trend of accidental intraoperative injuries. Study design We performed a cross-sectional study using the Nationwide Inpatient Sample database. The study population consisted of patients who encountered intraoperative injuries between 2003 and 2010. Controls were randomly selected from patients who underwent similar procedures during the same period. Cost was adjusted for inflation rate to reflect 2015 dollar values. Results A total of 61,667 cases with intraoperative injuries and 430,424 controls were included. Intraoperative injuries were most common in procedures that involved the digestive system (38.0%), female reproductive organs (21.4%), and musculoskeletal system (12.2%). There was a significant increase in those injuries from 161.3 cases/100,000 procedures in 2003 to 254.9 cases/100,000 procedures in 2010 (p Conclusions Certain demographic and clinical factors influence the risk of intraoperative injury of Nearby Structures. The prevalence of intraoperative injuries is increasing at the national level, and these injuries are associated with increased mortality and pose substantial clinical and financial burdens.
Elio El Kahi - One of the best experts on this subject based on the ideXlab platform.
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Behavior of Structures subjected to differential settlements: Taking uncertainties into consideration
2020Co-Authors: Elio El KahiAbstract:The objective of this thesis is to study the behavior of Structures subjected to differential settlement, taking into consideration different sources of uncertainties. Ground movements may have different “sources” (origins), such as the influence of Nearby excavations (tunnels), and the presence of underground voids (mining subsidence, sinkhole, etc.). These sources will induce the settlement of soil and its displacement. The soil settlement produced by the ground movements will affect the Nearby Structure, which will cause the Structure movement and its possible damage. This thesis, presented in “papers’ form” has the intention of evaluating the influence of uncertainties based on analytical, numerical and experimental approaches. At first, this study starts by developing an analytical model to study the effect of some important variabilities/uncertainties (soil profile deformation form, soil behavior (elastic/elastoplastic), variability of building stiffness, etc.). Then, a numerical model is developed in order to confirm some particular results given by the analytical model. Finally, an experimental model is dedicated to characterize one important uncertainty in particular, the variability of the Structure stiffness, and to study its influence on the transmission of the ground movement. The main results are the evaluation of confidence intervals that consider the effect of these uncertainties on the Structure response affecting the soil-Structure interaction (SSI) phenomenon, and the development of a methodology to quantify the impact of uncertainties on the estimation of the deflection transmission rate.
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Behavior of Structures subjected to differential settlements : Taking uncertainties into consideration
2020Co-Authors: Elio El KahiAbstract:L'objectif de cette thèse est d'étudier le comportement des Structures soumises à un tassement différentiel, en prenant en compte différentes sources d'incertitudes. Les mouvements de terrain peuvent avoir différentes «sources» (origines), telles que l’influence d’excavations à proximité (tunnels) et la présence de vides souterrains (affaissement minier, fontis, etc.). Ces sources induiront le tassement du sol et son déplacement. Le tassement du sol produit par les mouvements du sol affectera la Structure, ce qui provoquera le mouvement de la Structure et ses dommages éventuels. Cette thèse, présentée sous forme d’articles, a pour objectif d’évaluer l’influence des incertitudes sur la base d’approches analytique, numérique et expérimentale. Dans un premier temps, cette étude commence par développer un modèle analytique pour étudier l’effet de certaines variabilités / incertitudes importantes (forme de déformation du profil du sol, comportement du sol (élastique / élastoplastique), variabilité de la rigidité du bâtiment, etc.). Ensuite, un modèle numérique est développé afin de confirmer certains résultats particuliers donnés par le modèle analytique. Enfin, un modèle expérimental est dédié à la caractérisation d'une incertitude importante en particulier, la variabilité de la rigidité de la Structure, et à l'étude de son influence sur le taux de transmission du mouvement du sol. Les principaux résultats sont l'évaluation des intervalles de confiance prenant en compte l'effet de ces incertitudes sur la réponse de la Structure affectant le phénomène d'interaction sol-Structure (ISS), ainsi que la mise au point d'une méthodologie permettant de quantifier l'impact des incertitudes sur l'estimation du taux de transmission.The objective of this thesis is to study the behavior of Structures subjected to differential settlement, taking into consideration different sources of uncertainties. Ground movements may have different “sources” (origins), such as the influence of Nearby excavations (tunnels), and the presence of underground voids (mining subsidence, sinkhole, etc.). These sources will induce the settlement of soil and its displacement. The soil settlement produced by the ground movements will affect the Nearby Structure, which will cause the Structure movement and its possible damage. This thesis, presented in “papers’ form” has the intention of evaluating the influence of uncertainties based on analytical, numerical and experimental approaches. At first, this study starts by developing an analytical model to study the effect of some important variabilities/uncertainties (soil profile deformation form, soil behavior (elastic/elastoplastic), variability of building stiffness, etc.). Then, a numerical model is developed in order to confirm some particular results given by the analytical model. Finally, an experimental model is dedicated to characterize one important uncertainty in particular, the variability of the Structure stiffness, and to study its influence on the transmission of the ground movement. The main results are the evaluation of confidence intervals that consider the effect of these uncertainties on the Structure response affecting the soil-Structure interaction (SSI) phenomenon, and the development of a methodology to quantify the impact of uncertainties on the estimation of the deflection transmission rate
