In many parts of the world, civilians and peacekeepers are exposed to potentially serious injury from blasts and explosions. Providing insight into the trauma thresholds for blast injury is necessary for the development of blast protection equipment and identification and subsequent treatment of blast injury. [Phillips, 1988] Blast injury can be categorized as primary, secondary, tertiary, quaternary and quinernary, corresponding to different aspects of the blast loading and injury mechanisms. Primary blast injury occurring in the lungs is of importance, since lung injury results in one of the highest rate of blast mortality. Much of the existing blast injury data was obtained from animal testing with sheep and subsequently extrapolated to humans using scaling techniques. More recently, mathematical, experimental and numerical models have been developed and employed to investigate blast injury. In this study, a detailed finite element model of a sheep thorax and human thorax (developed at the University of Waterloo) was used to predict primary blast lung injury based on a range of blast loading conditions. The models were developed based on available anatomical data and material properties to model the organs and tissues, and were evaluated using the LS-Dyna explicit finite element code. The models were previously validated for the prediction of lung PBI using Friedlander-type blast waves. All results were compared to existing literature to further verify and validate the numerical models as wells as to provide insight on the effect of loading conditions on blast injury. The blast loading input for these simulations used idealized blast waves, based on a blast physics approach. Blast loads were verified using the Chinook CFD software. The effects of idealized blast waves on predicted lung injury were investigated to determine the importance of peak pressure, blast wave duration and impulse. The duration and peak pressures for the waves were selected based on the Bowen and UVa curves, and included a right angle triangular shape and a square wave to allow for the different parameters to be considered. These results were compared to the Bowen and revised Bowen injury models. The results show that the peak overpressure is dominant in predicting injury for blast loads with long durations (>8 ms). The impulse was dominant in predicting injury for blast loads with short durations (<1 ms). For blasts loads with intermediate durations (1 ms < 8 ms) both the shape of the blast load wave and peak overpressure play a role in primary blast lung injury. The effect of orientation of the body position on primary blast lung injury was investigated. Simulations were performed using the sheep and human numerical models along with a model of a commonly used experimental device, the Blast Test Device (BTD) cylinder. These models were oriented in different positions by rotating the body relative to the blast flow. Injury results for the BTD were calculated using the Injury 8.1 injury prediction software. The BTD simulations served several purposes; it was used as a reference for the human and sheep simulations and its effectiveness as a tool to predict body orientation was evaluated. In general, all of the models predicted appropriate and similar levels of injury for the body in its default orientation, and these predictions were comparable to the accepted injury levels for this insult. For other orientations the BTD was not able to predict the appropriate blast injury. This highlighted the importance of proper placement and orientation of the BTD when used in simulations or physical experiments. The overall injury (based on the results from the right and left lung) predicted by the sheep and human thorax was similar for all orientations. However, very different results were obtained when the predicted injury for the right and left lungs was compared. The differences between the sheep and the human were examined and the differences in injury between the right and left lung is a result of the differences in anatomy between the two species. This study has evaluated the importance of blast wave parameters in predicting primary blast injury, an important consideration for the improvement of blast protection, and the effect of body orientation on primary blast injury, an important consideration for experimental testing and a starting point for the evaluation of complex blast loading. Future work will focus on the evaluation of injury in complex blast environments.

In many parts of the world, civilians and peacekeepers are exposed to potentially serious injury from blasts and explosions. Providing insight into the trauma thresholds for blast injury is necessary for the development of blast protection equipment and identification and subsequent treatment of blast injury. [Phillips, 1988] Blast injury can be categorized as primary, secondary, tertiary, quaternary and quinernary, corresponding to different aspects of the blast loading and injury mechanisms. Primary blast injury occurring in the lungs is of importance, since lung injury results in one of the highest rate of blast mortality. Much of the existing blast injury data was obtained from animal testing with sheep and subsequently extrapolated to humans using scaling techniques. More recently, mathematical, experimental and numerical models have been developed and employed to investigate blast injury. In this study, a detailed finite element model of a sheep thorax and human thorax (developed at the University of Waterloo) was used to predict primary blast lung injury based on a range of blast loading conditions. The models were developed based on available anatomical data and material properties to model the organs and tissues, and were evaluated using the LS-Dyna explicit finite element code. The models were previously validated for the prediction of lung PBI using Friedlander-type blast waves. All results were compared to existing literature to further verify and validate the numerical models as wells as to provide insight on the effect of loading conditions on blast injury. The blast loading input for these simulations used idealized blast waves, based on a blast physics approach. Blast loads were verified using the Chinook CFD software. The effects of idealized blast waves on predicted lung injury were investigated to determine the importance of peak pressure, blast wave duration and impulse. The duration and peak pressures for the waves were selected based on the Bowen and UVa curves, and included a right angle triangular shape and a square wave to allow for the different parameters to be considered. These results were compared to the Bowen and revised Bowen injury models. The results show that the peak overpressure is dominant in predicting injury for blast loads with long durations (>8 ms). The impulse was dominant in predicting injury for blast loads with short durations (<1 ms). For blasts loads with intermediate durations (1 ms < 8 ms) both the shape of the blast load wave and peak overpressure play a role in primary blast lung injury. The effect of orientation of the body position on primary blast lung injury was investigated. Simulations were performed using the sheep and human numerical models along with a model of a commonly used experimental device, the Blast Test Device (BTD) cylinder. These models were oriented in different positions by rotating the body relative to the blast flow. Injury results for the BTD were calculated using the Injury 8.1 injury prediction software. The BTD simulations served several purposes; it was used as a reference for the human and sheep simulations and its effectiveness as a tool to predict body orientation was evaluated. In general, all of the models predicted appropriate and similar levels of injury for the body in its default orientation, and these predictions were comparable to the accepted injury levels for this insult. For other orientations the BTD was not able to predict the appropriate blast injury. This highlighted the importance of proper placement and orientation of the BTD when used in simulations or physical experiments. The overall injury (based on the results from the right and left lung) predicted by the sheep and human thorax was similar for all orientations. However, very different results were obtained when the predicted injury for the right and left lungs was compared. The differences between the sheep and the human were examined and the differences in injury between the right and left lung is a result of the differences in anatomy between the two species. This study has evaluated the importance of blast wave parameters in predicting primary blast injury, an important consideration for the improvement of blast protection, and the effect of body orientation on primary blast injury, an important consideration for experimental testing and a starting point for the evaluation of complex blast loading. Future work will focus on the evaluation of injury in complex blast environments.

No description available.

CIVINS / The recent trend of using fine water mist systems to replace the legacy HALON-1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 micro droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed. / CIVINS

The ironmaking blast furnace (BF) remains the most significant and important process for the production of liquid iron. For the achievement of stable furnace operation and good performance, mathematical modellings at different levels increasingly become a powerful tool in developing better understanding of this multiphase flow system, in particular the gas-solid flow. This thesis represents an effort in this area. A simplified and continuum-based mathematical model is proposed and tested to predict the BF gas-solid flow at a macroscopic level. The results show that the simple model is able to predict the general features of the solid flow, including the effects of gas and solid flowrates, and materials properties. The simplified model can be readily implemented in a full process model that needs to have a quick response to change for the purpose of control and optimization. To overcome the difficulties encountered in continuum modelling, i.e. determination of constitutive correlations, and particularly the description of the stagnant zone when related to BF, a discrete model based on the coupling approach of discrete element method (DEM) and computational fluid dynamics (CFD) is then employed to investigate the gas-solid flow in a model BF at a microscopic level. The results confirm the effects of variables such as gas flow rate, solid flow rate, particle properties, and model types. More importantly, such an approach can generate abundant microscopic information such as flow structure (particle velocity, porosity, coordination number) and force structure, which are of paramount importance to elucidate the gas-solid flow mechanisms, and develop a more comprehensive understanding of BF gas-solid flow, such as the formation mechanism of the stagnant zone. Further, the transient gas-solid flow phenomena, together with the considerations of cohesive zones and hearth liquid, can be predicted. Further, in order to develop understanding of thermal behaviour and elucidate the heat transfer mechanisms occurring in particle-fluid flow system, a new model is proposed by extending the DEM-CFD, and then tested in gas fluidization. The model considers the three heat transfer modes, and demonstrates its ability in investigating the heat transfer mechanisms, and offers an effective method to elucidate the mechanisms governing the heat transfer in particle-fluid systems at a particle scale. It is recommended to apply to the study of BF thermal behaviour.

Le codage espace-temps est une technique qui permet d'exploiter de façon très efficace la diversité spatiale et temporelle présente dans certains systèmes de communication, dont le canal sans fil. Le principal avantage de cette technique est une très grande efficacité spectrale. Dans nos jours, où le canal radio-mobile est de plus en plus utilisé pour transmettre tout type d'information, les méthodes permettant une utilisation plus efficace du spectre électromagnétique ont une importance fondamentale. Les algorithmes de réception connus aujourd'hui sont très complexes, même en ce qui concerne les codes espace-temps les plus simples. Cette complexité reste l'un des obstacles principaux à l'exploitation commerciale de ces codes. Cette thèse présente une étude très détaillée de la complexité, la performance, et les aspects les plus intéressants du comportement des algorithmes de réception pour des codes espace-temps, étude qui présente un moyen rapide pour une éventuelle conception des architectures adaptées à ce problème. Parmi les sujets présentés dans cette thèse, une étude approfondie de la performance de ces algorithmes a été réalisée, ayant pour objectif d'avoir une connaisance suffisante pour pouvoir choisir, parmi le grand nombre d'algorithmes connus, le mieux adapté à chaque système particulier. Des améliorations aux algorithmes connus ont aussi été proposées et analysées.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 91-101).

Radiocarbon datings in a previous study suggested that Moshyttan in Nora bergslag is the oldest blast furnace in Sweden and Europe. The aim of this study was specifically to study the origin of the Moshyttan blast furnace to answer the question: when was the blast furnace at Moshyttan established? To this end, a 2.5 m sediment record was collected from Fickeln, a lake 600 m downstream of Moshyttan, in March 2012. The geochemical properties of the sediment record were analyzed for major and trace elements using XRF. The organic content was calculated from the ash residue following the mercury analyses as a proxy for organic matter. Pollen and charcoal were analyzed using a standardized method. A age- depth model was created based on four radiocarbon datings of the sediment profile. The pollen data suggest that early land use consisted of forest grazing from about AD 220, and agriculture from about AD 880. An increase in Pb and charcoal particles about AD 880 indicates early metallurgy in the area. The first significant evidence of the establishment of a blastfurnace was between AD 1020 and AD 1090 marked by a decrease in organic content combined with a strong increase of ore related metals such as Pb, Zn, Cu and a strong increase of charcoal particles. Within the uncertainty of the age-depth modeling, the results from this study offers support to Wetterholms radiocarbon datings, thus making Moshyttan the oldest known blast furnace in Sweden and Europe.

The prevalence of injuries sustained from blast have been increasing over the past few decades due to the increasing use of Improvised Explosive Devices in areas where peacekeepers are deployed, as well as terrorist bombing incidents. The scope of this project was to evaluate the potential for head injury from primary effects in blast environments and to investigate protective aspects of protective equipment and new potential protective designs to mitigate or reduce the likelihood of Traumatic Brain Injury (TBI). In order to meet these goals, methods of blast loading as well as the kinematic response of the head when subjected to blast loading were investigated numerically and validated against experimental data. This was done for both low and mid heights of burst at varying standoff distances. The methods of loading considered were the basic spherical air burst formulation of the CONventional WEaPons algorithm (CONWEP), an advanced version of the algorithm that included ground reflection and mach stem formation, and a hemispherical surface burst which included ground reflection. The method that produced the most consistent results compared to the experiments was the enhanced version of CONWEP for mid level heights of burst; however, for low heights of burst, a novel “mirrored charge” setup provided the most accurate predictions. The kinematic response of the GEBOD numerical human body model, a rigid body representation of a 50th percentile male, was validated against experimental tests conducted by Defense Research and Development Canada (DRDC) for a range of standoff distances and Heights of Burst. It was found the response of the GEBOD was in good agreement with the DRDC experiments for peak acceleration, impulse and the Head Injury Criterion. The kinematic response of the head was investigated for various charge locations to study the effects of height of burst, lateral distance and standoff distance to the charge using the GEBOD numerical human body model. It was found that the standoff and height of burst had the largest influence on the acceleration experienced by the head. The height of burst study showed a large jump in the HIC15 injury criterion and head acceleration values when the charge was detonated within the region where a mach stem would form. As would be expected for the standoff distance from the charge, the closer the charge was to the body, the higher the accelerations experienced. A quasi two dimensional model of the human head at the mid-sagittal plane was developed in order to evaluate response at the tissue level, and the effect of protection. The sagittal head model was used to examine wave interactions in the fluid flow around the head during a blast event. This was achieved by utilizing an Arbitrary Langrangian-Eulerian formulation to model the blast loading. This model was also validated against experimental data such that it demonstrated the same kinematic response as the experimental tests under identical blast loading conditions. A helmet model was coupled to the sagittal head model using a layer of foam, and a statistical study was performed to determine the main effects and any interaction effects for the parameters of the numerical foam model. By analyzing these parameters and combining the best values for the effects, an optimum foam model was determined. This foam model was compared to actual foam materials and aluminum foam was found to have the closest properties to the idealized model. The aluminum foam material model was placed into the existing sagittal model and was found to have decreased the acceleration seen by the head under all the different loading cases considered. The maximum principal strain in the brain and the maximum intracranial pressure were also examined and compared to proposed injury criterion. For implementation in a helmet, an additional layer of comfort foam or some other soft material would have to be added between the head and the aluminum foam to prevent it from cutting or injuring the person. Some of the polymeric foams investigated could be used instead of aluminum foam; however, more data is required to properly define the material response at high strain rate loading. This study has shown that blast loading to the head can result in significant accelerations which could result in injury. By using common materials in the existing form of head protection, this potential for injury can be reduced.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 194-196).