WorldWideScience

Sample records for extreme blast loadings

  1. Composite Vessels for Containment of Extreme Blast Loadings

    Energy Technology Data Exchange (ETDEWEB)

    Pastrnak, J; Henning, C; Grundler, W; Switzer, V; Hollaway, R; Morrison, J; Hagler, L; Kokko, E; Deteresa, S; Hathcoat, B; Dalder, E

    2004-07-15

    A worldwide trend for explosives testing has been to replace open-air detonations with containment vessels, especially when any hazardous materials are involved. As part of the National Nuclear Security Administration's (NNSA) effort to ensure the safety and reliability of the nation's nuclear stockpile, researchers at Lawrence Livermore National Laboratory have been developing a high performance filament wound composite firing vessel that is nearly radiographically transparent. It was intended to contain a limited number of detonations of metal cased explosive assemblies in radiographic facilities such as the Advanced Hydrodynamic Facility (AHF) being studied by Los Alamos National Laboratory. A 2-meter diameter pressure vessel was designed to contain up to 35 kg (80 lb) of TNT equivalent explosive without leakage. Over the past 5 years a total of three half-scale (1 meter diameter) vessels have been constructed, and two of them were tested to 150% load with 8.2 kg (18-pound) spheres of C4 explosive. The low density and high specific strength advantages used in this composite vessel design may have other additional applications such as transporting sensitive explosives that could otherwise be moved only in very small quantities. Also, it could be used for highly portable, explosive containment systems for law enforcement.

  2. Spalling of concrete subjected to blast loading

    Directory of Open Access Journals (Sweden)

    Foglar M.

    2013-09-01

    Full Text Available This paper presents outcomes of the blast field tests of FRC and reinforced concrete specimens, which were performed in cooperation with the Czech Army corps and Police of the Czech Republic in the military training area Boletice. The numerical evaluation of the experiments focused on the spalling of concrete subjected to blast loading started after the first set of the tests, took almost 3 years and required further small-scale experiments performed in the labs of the Czech Technical University.

  3. Comparison between a typical and a simplified model for blast load-induced structural response

    Science.gov (United States)

    Abd-Elhamed, A.; Mahmoud, S.

    2017-02-01

    As explosive blasts continue to cause severe damage as well as victims in both civil and military environments. There is a bad need for understanding the behavior of structural elements to such extremely short duration dynamic loads where it is of great concern nowadays. Due to the complexity of the typical blast pressure profile model and in order to reduce the modelling and computational efforts, the simplified triangle model for blast loads profile is used to analyze structural response. This simplified model considers only the positive phase and ignores the suction phase which characterizes the typical one in simulating blast loads. The closed from solution for the equation of motion under blast load as a forcing term modelled either typical or simplified models has been derived. The considered herein two approaches have been compared using the obtained results from simulation response analysis of a building structure under an applied blast load. The computed error in simulating response using the simplified model with respect to the typical one has been computed. In general, both simplified and typical models can perform the dynamic blast-load induced response of building structures. However, the simplified one shows a remarkably different response behavior as compared to the typical one despite its simplicity and the use of only positive phase for simulating the explosive loads. The prediction of the dynamic system responses using the simplified model is not satisfactory due to the obtained larger errors as compared to the system responses obtained using the typical one.

  4. Behaviour of plated structures subjected to blast loading

    Directory of Open Access Journals (Sweden)

    Aune Vegard

    2015-01-01

    Full Text Available An experimental investigation using a new shock tube facility to study blast-load effects on thin aluminium plates is presented. The shock tube is designed to expose materials and structures to extreme loading conditions, such as accidental explosions or terrorist attacks. The intensity of the loading in the present study was determined by the initial conditions of the compressed gas, i.e. volume and pressure, and the resulting loading on the target plate was compared to experimental data from explosive detonations found in the literature. The square plates were manufactured from a low-strength aluminium alloy and had an exposed area of 0.3 × 0.3 m2. Piezoelectric pressure sensors were used for pressure recordings and synchronized with two high-speed cameras operating at a frame rate of 21,000 fps in a stereoscopic setup to capture the dynamic response using a three-dimensional digital image correlation (3D-DIC technique. The experiment showed that the shock tube is capable of recreating a loading similar to that of an unconfined far-field airblast, and worked as an easily controllable alternative to explosive detonations when studying the dynamic response of structures subjected to blast loading.

  5. Structural Analysis Of Offshore Structures Exposed To Blast Loads

    DEFF Research Database (Denmark)

    Hansen, Hans Jakup; Thygesen, Ulf; Kristensen, Anders

    2002-01-01

    Numerical methods for simulations of blast loads and resulting structural response are investigated and compared to results obtained from tests. The CFD code EXSIM is used for the simulation of the blast load. This code provides a load profile wich is entered in the FEM analysis model....

  6. Soil Behavior Under Blast Loading

    Science.gov (United States)

    2010-12-01

    compressive stress of creep loading causes the pore water pressure to increase. If drainage is possible an outflow of water then takes place into...behavior such as creep and temperature-dependency. Those aspects are not discussed here because they are beyond the scopes in this study. 2.2.2...0.00060 0.0012 0.0020 0.0040 0.0060 $ P9 P10 0.0080 0.041 *MAT_USER_DEFINED_MATERIAL_MODELS $ MID RO

  7. Moving in extreme environments:extreme loading; carriage versus distance

    OpenAIRE

    Lucas, Samuel J. E.; Helge, Jørn W.; Schütz, Uwe H W; Goldman, Ralph F.; Cotter, James D

    2016-01-01

    This review addresses human capacity for movement in the context of extreme loading and with it the combined effects of metabolic, biomechanical and gravitational stress on the human body. This topic encompasses extreme duration, as occurs in ultra-endurance competitions (e.g. adventure racing and transcontinental races) and expeditions (e.g. polar crossings), to the more gravitationally limited load carriage (e.g. in the military context). Juxtaposed to these circumstances is the extreme met...

  8. Explosion induced dynamic responses of blast wall on FPSO topside: Blast loading application methods

    Directory of Open Access Journals (Sweden)

    Ki-Yeob Kang

    2017-03-01

    Full Text Available Topside areas on an offshore oil and gas platform are highly susceptible to explosion. A blast wall on these areas plays an important role in preventing explosion damage and must withstand the expected explosion loads. The uniformly distributed loading condition, predicted by Explosion Risk Analyses (ERAs, has been applied in most of the previous analysis methods. However, analysis methods related to load conditions are inaccurate because the blast overpressure around the wall tends to be of low-level in the open area and high-level in the enclosed area. The main objectives of this paper are to study the effects of applying different load applications and compare the dynamic responses of the blast wall. To do so, various kinds of blast pressures were measured by Computational Fluid Dynamics (CFD simulations on the target area. Nonlinear finite element analyses of the blast wall under two types of identified dynamic loadings were also conducted.

  9. Explosion induced dynamic responses of blast wall on FPSO topside: Blast loading application methods

    OpenAIRE

    Kang, Ki-Yeob; Choi, Kwang-Ho; Choi, Jae Woong; Ryu, Yong Hee; Lee, Jae-Myung

    2017-01-01

    Topside areas on an offshore oil and gas platform are highly susceptible to explosion. A blast wall on these areas plays an important role in preventing explosion damage and must withstand the expected explosion loads. The uniformly distributed loading condition, predicted by Explosion Risk Analyses (ERAs), has been applied in most of the previous analysis methods. However, analysis methods related to load conditions are inaccurate because the blast overpressure around the wall tends to be of...

  10. Numerical Investigation of Structural Response of Corrugated Blast Wall Depending on Blast Load Pulse Shapes

    Directory of Open Access Journals (Sweden)

    Jung Min Sohn

    Full Text Available Abstract Hydrocarbon explosions are one of most hazardous events for workers on offshore platforms. To protect structures against explosion loads, corrugated blast walls are typically installed. However, the profiles of real explosion loads are quite different depending on the congestion and confinement of Topside structures. As the level of congestion and confinement increases, the explosion load increases by up to 8 bar, and the rising time of the load decreases. This study primarily aims to investigate the structural behavior characteristics of corrugated blast walls under different types of explosion loadings. Four loading shapes were applied in the structural response analysis, which utilized a dynamic nonlinear finite element method.

  11. Experimental study of masonry wall exposed to blast loading

    OpenAIRE

    S.; Ahmad; Elahi, A.; Pervaiz, H.; Rahman, A.G.A.; Barbhuiya, S.

    2014-01-01

    The challenge of protecting the nation against the attack of terrorism has raised the importance to explore the understanding of building materials against the explosion. Unlike most of the building materials, brick masonry materials offer relatively small resistance against blast loading. In this research, a brick masonry wall was exposed to varying blast load at different scaled distances. Six tests with different amounts of explosives at various distances were carried out. Pressure time hi...

  12. Hybrid S2/Carbon Epoxy Composite Armours Under Blast Loads

    Science.gov (United States)

    Dolce, F.; Meo, Michele; Wright, A.; French, M.; Bernabei, M.

    2012-06-01

    Civil and military structures, such as helicopters, aircrafts, naval ships, tanks or buildings are susceptible to blast loads as terroristic attacks increases, therefore there is the need to design blast resistant structures. During an explosion the peak pressure produced by shock wave is much greater than the static collapse pressure. Metallic structures usually undergo large plastic deformations absorbing blast energy before reaching equilibrium. Due to their high specific properties, fibre-reinforced polymers are being considered for energy absorption applications in blast resistant armours. A deep insight into the relationship between explosion loads, composite architecture and deformation/fracture behaviour will offer the possibility to design structures with significantly enhanced energy absorption and blast resistance performance. This study presents the results of a numerical investigation aimed at understanding the performance of a hybrid composite (glass/carbon fibre) plate subjected to blast loads using commercial LS-DYNA software. In particular, the paper deals with numerical 3D simulations of damages caused by air blast waves generated by C4 charges on two fully clamped rectangular plates made of steel and hybrid (S2/Carbon) composite, respectively. A Multi Materials Arbitrary Lagrangian Eulerian (MMALE) formulation was used to simulate the shock phenomenon. For the steel plates, the Johnson-Cook material model was employed. For the composite plates both in-plane and out-of-plane failure criteria were employed. In particular, a contact tiebreak formulation with a mixed mode failure criteria was employed to simulate delamination failure. As for the steel plates the results showed that excellent correlation with the experimental data for the two blast load conditions in terms of dynamic and residual deflection for two different C4 charges. For the composite plates the numerical results showed that, as expected, a wider delamination damage was observed

  13. Stochastic Extreme Load Predictions for Marine Structures

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    1999-01-01

    Development of rational design criteria for marine structures requires reliable estimates for the maximum wave-induced loads the structure may encounter during its operational lifetime. The paper discusses various methods for extreme value predictions taking into account the non-linearity of the ......Development of rational design criteria for marine structures requires reliable estimates for the maximum wave-induced loads the structure may encounter during its operational lifetime. The paper discusses various methods for extreme value predictions taking into account the non...

  14. Evaluation of Blast Resistance of Fiber Reinforced Composite Specimens under Contact Blast Load

    Science.gov (United States)

    Janota, O.; Foglar, M.

    2017-09-01

    This paper presents results of experimental programme which took place in 2014, 2015 and 2016. Experiments were focused on the resistance of full scale concrete panels subjected to contact blast loading. Specimens were loaded by contact blast by plastic explosive. All specimens were reinforced concrete slabs made of fiber concrete. Basalt mesh and textile sheets were added to some of the experiments for creating more heterogeneous material to achieve better resistance of the specimens. Evaluation of experiments was mainly focused on the damaged area on the contact side and soffit of the specimens. Dependency of the final damage of concrete panels on the weight of explosive and concrete strength was assessed.

  15. Failure of underground concrete structures subjected to blast loadings

    Science.gov (United States)

    Ross, C. A.; Nash, P. T.; Griner, G. R.

    1979-01-01

    The response and failure of two edges of free reinforced concrete slabs subjected to intermediate blast loadings are examined. The failure of the reinforced concrete structures is defined as a condition where actual separation or fracture of the reinforcing elements has occurred. Approximate theoretical methods using stationary and moving plastic hinge mechanisms with linearly varying and time dependent loadings are developed. Equations developed to predict deflection and failure of reinforced concrete beams are presented and compared with the experimental results.

  16. On dimensionless loading parameters for close-in blasts

    Directory of Open Access Journals (Sweden)

    K Micallef

    2016-10-01

    Full Text Available Close-range blasts pose a threat through severe damage to structures and injury or death. In this work, the spatial and temporal descriptions of a localised blast load are presented using 6 non-dimensional parameters. These are found to be solely functions of the charge stand-off distance to diameter ratio for a cylindrically-shaped charge. Numerical simulations of a localised blast are performed using AUTODYN, where the pressure variation on a rigid barrier for various charge stand-off/diameter combinations is obtained. The least-square regression is then utilised to obtain the relationship between stand-off/diameter ratio and dimensionless loading parameters. The relevant expressions and dimensionless charts are presented. The proposed equations are verified by comparing experimental data with numerical results obtained by finite element analysis (FEA of blast loaded steel plates (using the user-defined subroutine VDLOAD implemented in the FEA package ABAQUS/Explicit. Excellent correlation of the measured permanent displacement with numerically predicted results is obtained.

  17. Finite Element Analysis for CFST Columns under Blast Loading

    Directory of Open Access Journals (Sweden)

    Peyman Beiranvand

    2017-10-01

    Full Text Available The columns of frame structures are the key load-bearing components and the exterior columns are susceptible to attack in terrorist blasts. When subjected to blast loads, the columns would suffer a loss of bearing capacity to a certain extent due to the damage imparted which may lead to their collapse and even cause the progressive collapse of the whole structure . The concrete-filled steel columns have been extensively used in the world due to the existence of all suitable characteristics of concrete and steel, more ductility, increasing concrete confinement using the steel wall, the large energy-absorption capacity and the appropriate fire behavior. In the present study, the concrete-filled steel square columns have been simulated under the influence of the blast load using the ABAQUS software. These responses have been compared for scaled distances based on the distance to the source and the weight of the explosive material. As a result, it can be seen that although concrete deformation has been restricted using the steel tube, the inner layer of concrete has been seriously damaged and the column displacement has been decreased by increasing the scaled distance. We also concluded that the concrete-filled steel columns have the high ductility and the blast resistance.

  18. Outlier robustness for wind turbine extrapolated extreme loads

    DEFF Research Database (Denmark)

    Natarajan, Anand; Verelst, David Robert

    2012-01-01

    simulation is demonstrated and compared with published results. Further effects of varying wind inflow angles and shear exponent is brought out. Parametric fitting techniques that consider all extreme loads including ‘outliers’ are proposed, and the physical reasons that result in isolated high extreme loads...... dependencies is utilized to estimate a probability for the largest extreme load to occur at a specific mean wind speed. This inherently weights extreme loads that occur frequently within mean wind speed bins higher than isolated occurrences of extreme loads. Primarily, the results for the blade root out......-of-plane loads are presented here as those extrapolated loads have shown wide variability in literature, but the method can be generalized to any other component load. The convergence of the 1 year extrapolated extreme blade root out-of-plane load with the number of turbulent wind samples used in the loads...

  19. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2014-01-01

    Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

  20. Modelling and Dynamic Response of Steel Reticulated Shell under Blast Loading

    Directory of Open Access Journals (Sweden)

    Ximei Zhai

    2013-01-01

    Full Text Available Explicit finite element programme LS-DYNA was used to simulate a long-span steel reticulated shell under blast loading to investigate the structural dynamic responses in this paper. The elaborate finite element model of the Kiewitt-8 single-layer reticulated shell with span of 40 m subjected to central blast loading was established and all the process from the detonation of the explosive charge to the demolition, including the propagation of the blast wave and its interaction with structure was reproduced. The peak overpressure from the numerical analysis was compared with empirical formulas to verify the credibility and applicability of numerical simulation for blast loading. The dynamic responses of the structure under blast loading with different TNT equivalent weights of explosive and rise-span ratios were obtained. In addition, the response types of Kiewitt-8 single-layer reticulated shell subjected to central explosive blast loading were defined.

  1. Predicting reinforced concrete response to blast loads

    National Research Council Canada - National Science Library

    Jacques, Eric; Lloyd, Alan; Saatcioglu, Murat

    2013-01-01

    .... The results are presented in graphical format in terms of structural load-deformation characteristics, single degree of freedom displacement--time histories and iso-displacement pressure-impulse diagrams...

  2. Investigation of Axial Strengthened Reinforced Concrete Columns under Lateral Blast Loading

    National Research Council Canada - National Science Library

    Mohammad Esmaeilnia Omran; Somayeh Mollaei

    2017-01-01

    .... Therefore, an experimental explosion loading has been done on RC members by the authors. Four RC components, with identical geometry and material, with and without axial load were imposed to air blast...

  3. A shock tube facility to generate blast loading on structures

    OpenAIRE

    Aune, Vegard; Fagerholt, Egil; Langseth, Magnus; Børvik, Tore

    2016-01-01

    This study evaluates the performance of a new shock tube facility used to produce blast loading in controlled laboratory environments. The facility was found to generate a planar shock wave over the tube cross section by measuring the pressure distribution on a massive steel plate located at the end of the tube. The properties of the shock wave proved to be a function of driver length and driver pressure, and the positive phase of the measured pressure–time histories was similar to those gene...

  4. Properties and Behavior of Geopolymer Concrete Subjected to Explosive Air Blast Loading: A Review

    Directory of Open Access Journals (Sweden)

    Mohd Mortar Nurul Aida

    2017-01-01

    Full Text Available The severe damage to civilian buildings, public area, jet aircraft impact and defense target under explosive blast loading can cause a huge property loss. Most of researcher discusses the topics on design the concrete material model to sustain againts the explosive detonation. The implementation of modern reinforcement steels and fibres in ordinary Portland cement (OPC concrete matrix can reduce the extreme loading effects. However, most researchers have proved that geopolymer concrete (GPC has better mechanical properties towards high performance concrete, compared to OPC. GPC has the high early compressive strength and high ability to resist the thermal energy from explosive detonation. In addition, OPC production is less environmental friendly than geopolymer cement. Geopolymer used can lead to environmental protection besides being improved in mechanical properties. Thus, this paper highlighted on an experimental, numerical and the analytical studies cause of the explosive detonation impact to concrete structures.

  5. High-fidelity simulations of blast loadings in urban environments using an overset meshing strategy

    Science.gov (United States)

    Wang, X.; Remotigue, M.; Arnoldus, Q.; Janus, M.; Luke, E.; Thompson, D.; Weed, R.; Bessette, G.

    2017-05-01

    Detailed blast propagation and evolution through multiple structures representing an urban environment were simulated using the code Loci/BLAST, which employs an overset meshing strategy. The use of overset meshes simplifies mesh generation by allowing meshes for individual component geometries to be generated independently. Detailed blast propagation and evolution through multiple structures, wave reflection and interaction between structures, and blast loadings on structures were simulated and analyzed. Predicted results showed good agreement with experimental data generated by the US Army Engineer Research and Development Center. Loci/BLAST results were also found to compare favorably to simulations obtained using the Second-Order Hydrodynamic Automatic Mesh Refinement Code (SHAMRC). The results obtained demonstrated that blast reflections in an urban setting significantly increased the blast loads on adjacent buildings. Correlations of computational results with experimental data yielded valuable insights into the physics of blast propagation, reflection, and interaction under an urban setting and verified the use of Loci/BLAST as a viable tool for urban blast analysis.

  6. Full-scale testing of leakage of blast waves inside a partially vented room exposed to external air blast loading

    Science.gov (United States)

    Codina, R.; Ambrosini, D.

    2017-06-01

    For the last few decades, the effects of blast loading on structures have been studied by many researchers around the world. Explosions can be caused by events such as industrial accidents, military conflicts or terrorist attacks. Urban centers have been prone to various threats including car bombs, suicide attacks, and improvised explosive devices. Partially vented constructions subjected to external blast loading represent an important topic in protective engineering. The assessment of blast survivability inside structures and the development of design provisions with respect to internal elements require the study of the propagation and leakage of blast waves inside buildings. In this paper, full-scale tests are performed to study the effects of the leakage of blast waves inside a partially vented room that is subjected to different external blast loadings. The results obtained may be useful for proving the validity of different methods of calculation, both empirical and numerical. Moreover, the experimental results are compared with those computed using the empirical curves of the US Defense report/manual UFC 3-340. Finally, results of the dynamic response of the front masonry wall are presented in terms of accelerations and an iso-damage diagram.

  7. Mitigating the Long term Operating Extreme Load through Active Control

    DEFF Research Database (Denmark)

    Koukoura, Christina; Natarajan, Anand

    2014-01-01

    blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting...... on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral Ki gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined...

  8. Simulations under uncertainty for occupant safety for a vehicle subjected to a blast load

    NARCIS (Netherlands)

    Sun, J.; Vlahopoulos, N.; Stabryla, T.J.; Goetz, R.; Velde, R. van de

    2006-01-01

    One of the main threats to military vehicles originates from landmine blasts. In order to improve the survivability of the occupants it is important to design a military vehicle for increased occupant safety. Simulation technology that combines modeling of the blast loads from the landmine

  9. Wind simulation for extreme and fatigue loads

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, M.; Larsen, G.C.; Mann, J.; Ott, S.; Hansen, K.S.; Pedersen, B.J.

    2004-01-01

    Measurements of atmospheric turbulence have been studied and found to deviate from a Gaussian process, in particular regarding the velocity increments over small time steps, where the tails of the pdf are exponential rather than Gaussian. Principles for extreme event counting and the occurrence of cascading events are presented. Empirical extreme statistics agree with Rices exceedence theory, when it is assumed that the velocity and its time derivative are independent. Prediction based on the assumption that the velocity is a Gaussian process underpredicts the rate of occurrence of extreme events by many orders of magnitude, mainly because the measured pdf is non-Gaussian. Methods for simulation of turbulent signals have been developed and their computational efficiency are considered. The methods are applicable for multiple processes with individual spectra and probability distributions. Non-Gaussian processes are simulated by the correlation-distortion method. Non-stationary processes are obtained by Bezier interpolation between a set of stationary simulations with identical random seeds. Simulation of systems with some signals available is enabled by conditional statistics. A versatile method for simulation of extreme events has been developed. This will generate gusts, velocity jumps, extreme velocity shears, and sudden changes of wind direction. Gusts may be prescribed with a specified ensemble average shape, and it is possible to detect the critical gust shape for a given construction. The problem is formulated as the variational problem of finding the most probable adjustment of a standard simulation of a stationary Gaussian process subject to relevant event conditions, which are formulated as linear combination of points in the realization. The method is generalized for multiple correlated series, multiple simultaneous conditions, and 3D fields of all velocity components. Generalization are presented for a single non-Gaussian process subject to relatively

  10. Investigation of Axial Strengthened Reinforced Concrete Columns under Lateral Blast Loading

    Directory of Open Access Journals (Sweden)

    Mohammad Esmaeilnia Omran

    2017-01-01

    Full Text Available Different factors can affect blast response of structural components. Hence, experimental tests could be the best method for evaluating structures under blast loading. Therefore, an experimental explosion loading has been done on RC members by the authors. Four RC components, with identical geometry and material, with and without axial load were imposed to air blast. Observed data of the members’ response under blast loading was used for validation of finite element modeling process using ABAQUS software. With respect to complexity, limitations, and high costs of experimental tests, analytical studies and software modeling can be good alternatives. Accordingly, in this paper, the behavior of 6 different models of normal and strengthened RC columns under blast loading was evaluated using ABAQUS. Strengthening configurations considered here were designed for enhancing axial capacity of RC columns. Therefore, we can investigate the effectiveness of axial strengthening of column on its blast resistance capacity and residual axial strength. The considered strengthening methods were different steel jacket configurations including steel angle, channel, and plate sections. The results showed that retrofitting significantly improves blast performance of the columns. Moreover, residual strength capacity of the columns strengthened with steel channel is higher than the other models.

  11. Determination of explosive blast loading equivalencies with an explosively driven shock tube

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Scott I [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory; Morris, John S [Los Alamos National Laboratory

    2009-01-01

    Recently there has been significant interest in evaluating the potential of many different non-ideal energetic materials to cause blast damage. We present a method intended to quantitatively compare the blast loading generated by different energetic materials through use of an explosively driven shock tube. The test explosive is placed at the closed breech end of the tube and initiated with a booster charge. The resulting shock waves are then contained and focused by the tube walls to form a quasi-one-dimensional blast wave. Pressure transducers along the tube wall measure the blast overpressure versus distance from the source and allow the use of the one-dimensional blast scaling relationship to determine the energy deposited into the blast wave per unit mass of test explosive. These values are then compared for different explosives of interest and to other methods of equivalency determination.

  12. Experimental study of masonry wall exposed to blast loading

    Directory of Open Access Journals (Sweden)

    Ahmad, S.

    2014-03-01

    Full Text Available The challenge of protecting the nation against the attack of terrorism has raised the importance to explore the understanding of building materials against the explosion. Unlike most of the building materials, brick masonry materials offer relatively small resistance against blast loading. In this research, a brick masonry wall was exposed to varying blast load at different scaled distances. Six tests with different amounts of explosives at various distances were carried out. Pressure time history, acceleration time history and strain at specific location were measured. The parameters measured from experimental pressure time history and acceleration time history is compared with those determined by ConWep to establish the correlations between experimental determined records and ConWep values. The experimental results were also compared with some researchers. These correlations may assist in understanding the behaviour of masonry structures subjected to explosive loading.Con el reto que supone proteger a la nación contra atentados terroristas se ha visto acrecentada la importancia de conocer el comportamiento de materiales de construcción cuando se someten a una carga explosiva. Al contrario de la mayoría de los materiales, las fábricas de ladrillo ofrecen poca resistencia a dichas cargas. En el presente trabajo, se estudió el comportamiento de una fábrica de ladrillo ante cargas explosivas colocadas a diferentes distancias del muro. Se realizaron seis pruebas con explosivos de potencias distintas y a diferentes distancias. Se trazaron las curvas presión-tiempo y aceleración-tiempo, midiéndose asimismo la deformación en un punto concreto. Los valores experimentales de las curvas presión-tiempo y aceleración-tiempo se compararon con los que se calcularon con la ayuda de la aplicación informática ConWep a fin de establecer las correlaciones entre ambos conjuntos de resultados. También se compararon los resultados experimentales

  13. Manual for the prediction of blast and fragment loadings on structures

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    The purpose of this manual is to provide Architect-Engineer (AE) firms guidance for the prediction of air blast, ground shock and fragment loadings on structures as a result of accidental explosions in or near these structures. Information in this manual is the result of an extensive literature survey and data gathering effort, supplemented by some original analytical studies on various aspects of blast phenomena. Many prediction equations and graphs are presented, accompanied by numerous example problems illustrating their use. The manual is complementary to existing structural design manuals and is intended to reflect the current state-of-the-art in prediction of blast and fragment loads for accidental explosions of high explosives at the Pantex Plant. In some instances, particularly for explosions within blast-resistant structures of complex geometry, rational estimation of these loads is beyond the current state-of-the-art.

  14. Extreme and First-Passage Time of Ship Collision Loads

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Thoft-Christensen, Palle

    1983-01-01

    The paper outlines a general theory from which the distribution function of the extreme peak collision load encountered during a certain intended lifetime can be cal culated assuming the arrival of ship collisions to be specified by a Poisson counting proces s.......The paper outlines a general theory from which the distribution function of the extreme peak collision load encountered during a certain intended lifetime can be cal culated assuming the arrival of ship collisions to be specified by a Poisson counting proces s....

  15. Plastic Deformation of Metal Tubes Subjected to Lateral Blast Loads

    Directory of Open Access Journals (Sweden)

    Kejian Song

    2014-01-01

    Full Text Available When subjected to the dynamic load, the behavior of the structures is complex and makes it difficult to describe the process of the deformation. In the paper, an analytical model is presented to analyze the plastic deformation of the steel circular tubes. The aim of the research is to calculate the deflection and the deformation angle of the tubes. A series of assumptions are made to achieve the objective. During the research, we build a mathematical model for simply supported thin-walled metal tubes with finite length. At a specified distance above the tube, a TNT charge explodes and generates a plastic shock wave. The wave can be seen as uniformly distributed over the upper semicircle of the cross-section. The simplified Tresca yield domain can be used to describe the plastic flow of the circular tube. The yield domain together with the plastic flow law and other assumptions can finally lead to the solving of the deflection. In the end, tubes with different dimensions subjected to blast wave induced by the TNT charge are observed in experiments. Comparison shows that the numerical results agree well with experiment observations.

  16. Extreme load predictions for floating offshore wind turbines

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2009-01-01

    An effective stochastic procedure for extreme value predictions related to wave and wind induced stochastic loads is applied to a tension-leg concept for floating offshore wind turbines. The method is based on the First Order Reliability Method (FORM) and as the procedure makes use of only short...... time-domain simulations all kinds of non-linearities can be included. The procedure has been used previously for wave induced loads and is in this note extended to combined wave and wind loads....

  17. Simulation of Prestressed Concrete Sandwich Panels Subjected to Blast Loads (Preprint)

    Science.gov (United States)

    2010-02-01

    AFRL-RX-TY-TP-2010-0014 PREPRINT SIMULATION OF PRESTRESSED CONCRETE SANDWICH PANELS SUBJECTED TO BLAST LOADS Charles M. Newberry and...NUMBER (Include area code) 01-FEB-2010 Conference Paper PREPRINT 01-JAN-2009-- 31-DEC-2009 Simulation of Prestressed Concrete Sandwich Panels Subjected... concrete , sandwich panels, simulation, LS-DYNA, blast, tilt-up panels U U U UU 14 Paul Sheppard Reset Simulation of Prestressed Concrete Sandwich

  18. Blast-Loading Assessment of Multi-Energy Flash Computed Tomography (MEFCT) Diagnostic

    Science.gov (United States)

    2016-08-01

    information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY...blast loading, and addresses the implications of these movements on the reconstruction process. 15. SUBJECT TERMS blast, pressure gauge, flyer plate ...desired events dictates that the timescale of acquisition be reduced to the order of 100 ns to prevent motion blur. The system may also be subject to

  19. Rational calibration of three IEC extreme load cases

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

    2008-01-01

    This paper presents a rational and consistent calibration of the IEC 61400-1 extreme load cases EOG, EWS and ECD based on a system of asymptotic statistical models on closed form. The models are based on simple and easily accessible mean wind speed and turbulence characteristics of the atmospheric...

  20. Numerical Study of Damage Modes and Damage Assessment of CFST Columns under Blast Loading

    Directory of Open Access Journals (Sweden)

    Junhao Zhang

    2016-01-01

    Full Text Available Columns of frame structures are the key load-bearing components and the exterior columns are susceptible to attack in terrorist blasts. When subjected to blast loads, the columns would suffer a loss of bearing capacity to a certain extent due to the damage imparted, which may induce the collapse of them and even cause the progressive collapse of the whole structure. In this paper, the high-fidelity physics-based finite element program LS-DYNA was utilized to investigate the dynamic behavior and damage characteristics of the widely used concrete-filled steel tube (CFST columns subjected to blast loads. The established numerical model was calibrated with test data in open literatures. Possible damage modes of CFST columns under blast loading were analyzed, and the damage criterion based on the residual axial load capacity of the columns was adopted to assess the damage degree. A parametric study was conducted to investigate the effects of critical parameters such as blast conditions and column details on the damage degree of CFST columns. Based on the numerical simulation data, an empirical equation was proposed to estimate the variation of columns damage degree with the various parameters.

  1. Osteogenic differentiation of periosteum-derived stromal cells in blast-associated traumatic loading

    Science.gov (United States)

    Sory, David R.; Amin, Harsh D.; Rankin, Sara M.; Proud, William G.

    2017-06-01

    One of the most recurrent medical complications resulting from blast trauma includes blast-induced heterotopic ossification. Heterotopic ossification refers to the pathologic formation of extraskeletal bone in non-osseous tissue. Although a number of studies have established the interaction between mechanics and biology in bone formation following shock trauma, the exact nature of the mechanical stimuli associated to blast-loading and their influence on the activation of osteogenic differentiation of cells remain unanswered. Here we present the design and calibration of a loading platform compatible with living cells to examine the effects of mechanical stress pulses of blast-associated varying strain rates on the activation of osteogenic differentiation of periosteum (PO) cells. Multiaxial compression loadings of PO cells are performed at different magnitudes of stress and ranges of strain rate. A proof of concept is presented so as to establish a new window to address fundamental questions regarding blast injuries at the cellular level. This work was conducted under the auspices of the Royal British Legion Centre for Blast Injury Studies at Imperial College London. The authors would like to acknowledge the financial support of the Royal British Legion.

  2. Upper extremity improvements in chronic stroke: Coupled bilateral load training

    Science.gov (United States)

    Cauraugh, James H.; Coombes, Stephen A.; Lodha, Neha; Naik, Sagar K.; Summers, Jeffery J.

    2009-01-01

    Background The current treatment intervention study determined the effect of coupled bilateral training (i.e., bilateral movements and EMG-triggered neuromuscular stimulation) and resistive load (mass) on upper extremity motor recovery in chronic stroke. Methods Thirty chronic stroke subjects were randomly assigned to one of three behavioral treatment groups and completed 6 hours of rehabilitation in 4 days: (1) coupled bilateral training with a load on the unimpaired hand, (2) coupled bilateral training with no load on the unimpaired hand, and (3) control (no stimulation assistance or load). Results Separate mixed design ANOVAs revealed improved motor capabilities by the coupled bilateral groups. From the pretest to the posttest, both the coupled bilateral no load and load groups moved a higher number of blocks and demonstrated more regularity in the sustained contraction task. Faster motor reaction times across test sessions for the coupled bilateral load group provided additional evidence for improved motor capabilities. Conclusions Together these behavioral findings lend support to the contribution of coupled bilateral training with a load on the unimpaired arm to improved motor capabilities on the impaired arm. This evidence supports a neural explanation in that simultaneously moving both limbs during stroke rehabilitation training appears to activate balanced interhemispheric interactions while an extra load on the unimpaired limb provides stability to the system. PMID:19164850

  3. Comparison of extreme load extrapolations using measured and calculated loads of a MW wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Peeringa, J.M. [ECN Wind Energy, Petten (Netherlands)

    2009-04-15

    Since edition 3 of the standard IEC 61400-1 'Wind Turbines-Part 1; Design requirements' has been issued extreme load extrapolation during normal production is an important part of the wind turbine design and certification. At the ECN test site 'ECN Windturbine Testpark Wieringermeer' (EWTW) five in-line 2.5 MW turbines are used for research purposes. A data base with about 4 years of high quality load and meteorological measurements for a 2.5 MW wind turbine in free stream and wake conditions is available for research. This gives ECN the unique opportunity to compare extreme loads using extreme value statistics based on load simulations and load measurements for both free stream and wake conditions. Extreme load extrapolation will be applied on the flat blade root bending moment and the for aft tower bottom bending moment. Attention will be paid to the selection of the extreme value probability distribution and the amount of data needed.

  4. Blast Load Response of Steel Sandwich Panels with Liquid Encasement

    Energy Technology Data Exchange (ETDEWEB)

    Dale Karr; Marc Perlin; Benjamin Langhorst; Henry Chu

    2009-10-01

    We describe an experimental investigation of the response of hybrid blast panels for protection from explosive and impact forces. The fundamental notion is to dissipate, absorb, and redirect energy through plastic collapse, viscous dissipation, and inter-particle forces of liquid placed in sub-structural compartments. The panels are designed to absorb energy from an impact or air blast by elastic-plastic collapse of the panel substructure that includes fluid-filled cavities. The fluid contributes to blast effects mitigation by providing increased initial mass and resistance, by dissipation of energy through viscosity and fluid flow, and by redirecting the momentum that is imparted to the system from the impact and blast impulse pressures. Failure and deformation mechanisms of the panels are described.

  5. Finite Element Simulation and Assessment of Single-Degree-of-Freedom Prediction Methodology for Insulated Concrete Sandwich Panels Subjected to Blast Loads

    Science.gov (United States)

    2011-02-01

    sandwich panels for blast loads. blast load; finite element modeling; large deflection behavior; load-deflection response; precast concrete ; prestressed ...of Precast/ Prestressed Concrete Structures for Blast ...............................................6 3. MODEL DEVELOPMENT AND VALIDATION...Laboratory (AFRL) and a Daniel P. Jenny Research Fellowship Grant from the Precast/ Prestressed Concrete Institute (PCI). The current technical points of

  6. An adaptive time integration scheme for blast loading on a saturated soil mass

    NARCIS (Netherlands)

    Al-Khoury, R.; Weerheijm, J.; Dingerdis, K.; Sluys, L.J.

    2011-01-01

    This paper presents a time integration scheme capable of simulating blast loading of relatively high frequency on porous media, using coarse meshes. The scheme is based on the partition of unity finite element method. The discontinuity is imposed on the velocity field, while the displacement field

  7. In Vitro Studies of Primary Explosive Blast Loading on Neurons

    Science.gov (United States)

    2015-09-01

    YW. 2013. Blast induces oxi- dative stress, inflammation, neuronal loss, and subsequent short-term memory impairment in rats. Neuroscience 253:9–20...deprivation induces mitochondrial dysfunction and oxidative stress in PC12 cell line. J Cell Mol Med 7:49–56. Monnerie H, Tang-Schomer MD, Iwata A, Smith DH

  8. Scaled blast loading simulations on different vehicle bottom geometries

    NARCIS (Netherlands)

    Verreault, J.; Roebroeks, G.H.J.J.; Weerheijm, J.

    2016-01-01

    The development of new bottom concepts for military vehicles against mine blast threats involves the consideration of two main aspects: the bottom geometry and the material used. In order to reduce costs, experimental testing of new vehicle bottom concepts often requires small-scale setups together

  9. Transhumeral loading during advanced upper extremity activities of daily living.

    Directory of Open Access Journals (Sweden)

    Alex J Drew

    Full Text Available Percutaneous osseointegrated (OI implants for direct skeletal attachment of upper extremity prosthetics represent an alternative to traditional socket suspension that may yield improved patient function and satisfaction. This is especially true in high-level, transhumeral amputees where prosthetic fitting is challenging and abandonment rates remain high. However, maintaining mechanical integrity of the bone-implant interface is crucial for safe clinical introduction of this technology. The collection of population data on the transhumeral loading environment will aid in the design of compliance and overload protection devices that mitigate the risk of periprosthetic fracture. We collected marker-based upper extremity kinematic data from non-amputee volunteers during advanced activities of daily living (AADLs that applied dynamic loading to the humerus. Inverse dynamic analysis was applied to calculate the axial force, bending and torsional moments at three virtual amputation levels representing 25, 50, and 75% residual humeral length. The influences of amputation level, elbow flexion constraint, gender and anthropometric scaling were assessed. Results indicate that the proximal (25% amputation level experienced significantly higher axial forces and bending moments across all subjects when compared to distal amputation levels (p≤0.030. Constraining elbow flexion had a limited influence on peak transhumeral loads. Male subjects experienced higher axial forces during all evaluated activities (p≤0.023. Peak axial force for all activities occurred during jumping jacks (174.5N. Peak bending (57.6Nm and torsional (57.2Nm moments occurred during jumping jacks and rapid internal humeral rotation, respectively. Calculated loads fall within the range of implant fixation failure loads reported in cadaveric investigations of humeral stem fixation; indicating that periprosthetic fracture may occur during non-contact AADLs. These kinematic data, collected

  10. Extreme explosions supernovae, hypernovae, magnetars, and other unusual cosmic blasts

    CERN Document Server

    Stevenson, David S

    2013-01-01

    What happens at the end of the life of massive stars? At one time we thought all these stars followed similar evolutionary paths. However, new discoveries have shown that things are not quite that simple. This book focuses on the extreme -the most intense, brilliant and peculiar- of astronomical explosions. It features highly significant observational finds that push the frontiers of astronomy and astrophysics, particularly as before these objects were only predicted in theory.  This book is for those who want the latest information and ideas about the most dramatic and unusual explosions dete

  11. Dynamic response and optimal design of curved metallic sandwich panels under blast loading.

    Science.gov (United States)

    Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua

    2014-01-01

    It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  12. Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

    Directory of Open Access Journals (Sweden)

    Chang Qi

    2014-01-01

    Full Text Available It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  13. Resistance of Concrete Masonry Walls With Membrane Catcher Systems Subjected to Blast Loading

    Science.gov (United States)

    2010-12-01

    are made. sandwich panel, prestressed concrete , composite, test, explosive load U U U UU 22 Paul Sheppard Reset 1 Resistance of...AFRL-RX-TY-TP-2010-0090 RESISTANCE OF CONCRETE MASONRY WALLS WITH MEMBRANE CATCHER SYSTEMS SUBJECTED TO BLAST LOADING...Include area code) 29-DEC-2010 Refereed Journal Article 01-OCT-2008 -- 31-DEC-2009 Resistance of Concrete Masonry Walls With Membrane Catcher Systems

  14. Blast response of centrally and eccentrically loaded flat-, U-, and V-shaped armored plates: comparative study

    Science.gov (United States)

    Trajkovski, J.; Kunc, R.; Prebil, I.

    2017-07-01

    Light armored vehicles (LAVs) can be exposed to blast loading by landmines or improvised explosive devices (IEDs) during their lifetime. The bottom hull of these vehicles is usually made of a few millimeters of thin armored plate that is the vehicle's weak point in a blast-loading scenario. Therefore, blast resistance and blast load redirection are very important characteristics in providing adequate vehicle as well as occupant protection. Furthermore, the eccentric nature of loading caused by landmines was found to be omitted in the studies of simplified structures like beams and plates. For this purpose, blast wave dispersion and blast response of centrally and eccentrically loaded flat-, U-, and V-shaped plates are examined using a combined finite-element-smoothed-particle hydrodynamics (FE-SPH) model. The results showed that V-shaped plates better disperse blast waves for any type of loading and, therefore, can be successfully applied in LAVs. Based on the results of the study and the geometry of a typical LAV 6× 6, the minimum angle of V-shaped plates is also determined.

  15. Wave induced extreme hull girder loads on containerships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Pedersen, Preben Terndrup; Shi, Bill

    2009-01-01

    This paper provides simple but rational procedures for prediction of extreme wave – induced sectional hull girder forces with reasonable engineering accuracy. The procedures take into account main ship hull characteristics such as: length, breadth, draught, block coefficient, bow flare coefficient......, forward speed and hull flexibility. The vertical hull girder loads are evaluated for specific operational profiles. Firstly a quadratic strip theory is presented which can give separate predictions for the hogging and sagging bending moments and shear forces and for hull girder loads. Then this procedure...... is based on rational methods it can be applied for novel single hull ship types not presently covered by the rules of the classification societies or to account for specific operational profiles....

  16. Performance of Hybrid Steel Fibers Reinforced Concrete Subjected to Air Blast Loading

    Directory of Open Access Journals (Sweden)

    Mohammed Alias Yusof

    2013-01-01

    Full Text Available This paper presents the results of the experimental data and simulation on the performance of hybrid steel fiber reinforced concrete (HSFRC and also normal reinforced concrete (NRC subjected to air blast loading. HSFRC concrete mix consists of a combination of 70% long steel hook end fibre and also 30% of short steel hook end fibre with a volume fraction of 1.5% mix. A total of six concrete panels were subjected to air blast using plastic explosive (PE4 weighing 1 kg each at standoff distance of 0.3 meter. The parameters measured are mode of failure under static and blast loading and also peak overpressure that resulted from detonation using high speed data acquisition system. In addition to this simulation work using AUTODYN was carried out and validated using experimental data. The experimental results indicate that hybrid steel fiber reinforced concrete panel (HSFRC possesses excellent resistance to air blast loading as compared to normal reinforced concrete (NRC panel. The simulation results were also found to be close with experimental data. Therefore the results have been validated using experimental data.

  17. Blasting Vibration Safety Criterion Analysis with Equivalent Elastic Boundary: Based on Accurate Loading Model

    Directory of Open Access Journals (Sweden)

    Qingwen Li

    2015-01-01

    Full Text Available In the tunnel and underground space engineering, the blasting wave will attenuate from shock wave to stress wave to elastic seismic wave in the host rock. Also, the host rock will form crushed zone, fractured zone, and elastic seismic zone under the blasting loading and waves. In this paper, an accurate mathematical dynamic loading model was built. And the crushed zone as well as fractured zone was considered as the blasting vibration source thus deducting the partial energy for cutting host rock. So this complicated dynamic problem of segmented differential blasting was regarded as an equivalent elastic boundary problem by taking advantage of Saint-Venant’s Theorem. At last, a 3D model in finite element software FLAC3D accepted the constitutive parameters, uniformly distributed mutative loading, and the cylindrical attenuation law to predict the velocity curves and effective tensile curves for calculating safety criterion formulas of surrounding rock and tunnel liner after verifying well with the in situ monitoring data.

  18. Blast-induced biomechanical loading of the rat: an experimental and anatomically accurate computational blast injury model.

    Science.gov (United States)

    Sundaramurthy, Aravind; Alai, Aaron; Ganpule, Shailesh; Holmberg, Aaron; Plougonven, Erwan; Chandra, Namas

    2012-09-01

    Blast waves generated by improvised explosive devices (IEDs) cause traumatic brain injury (TBI) in soldiers and civilians. In vivo animal models that use shock tubes are extensively used in laboratories to simulate field conditions, to identify mechanisms of injury, and to develop injury thresholds. In this article, we place rats in different locations along the length of the shock tube (i.e., inside, outside, and near the exit), to examine the role of animal placement location (APL) in the biomechanical load experienced by the animal. We found that the biomechanical load on the brain and internal organs in the thoracic cavity (lungs and heart) varied significantly depending on the APL. When the specimen is positioned outside, organs in the thoracic cavity experience a higher pressure for a longer duration, in contrast to APL inside the shock tube. This in turn will possibly alter the injury type, severity, and lethality. We found that the optimal APL is where the Friedlander waveform is first formed inside the shock tube. Once the optimal APL was determined, the effect of the incident blast intensity on the surface and intracranial pressure was measured and analyzed. Noticeably, surface and intracranial pressure increases linearly with the incident peak overpressures, though surface pressures are significantly higher than the other two. Further, we developed and validated an anatomically accurate finite element model of the rat head. With this model, we determined that the main pathway of pressure transmission to the brain was through the skull and not through the snout; however, the snout plays a secondary role in diffracting the incoming blast wave towards the skull.

  19. Head Kinematics Resulting from Simulated Blast Loading Scenarios

    Science.gov (United States)

    2012-09-17

    The m h stem is call d that force a injury metri y metric to e pact power (H and rotationa d by recons s to an injury y [14] to prod sidered here...d or re. : the s the ad to f for This ave ected depe Mac poin F 2.4 In O recen 4) [2 C4 w tests is of their of 1. The path of nds...detonation (s 34 [15]. Figure 2 the triple poin harge size, st ses the press ases with incr blast and the Explosive D uring Freedo s in Afghanis

  20. Biomechanical model of the thorax under blast loading: a three dimensional numerical study.

    Science.gov (United States)

    Goumtcha, Aristide Awoukeng; Thoral-Pierre, Karine; Roth, Sébastien

    2014-12-01

    Injury mechanisms due to high speed dynamic loads, such as blasts, are not well understood. These research fields are widely investigated in the literature, both at the experimental and numerical levels, and try to answer questions about the safety and efficiency of protection devices or biomechanical traumas. At a numerical level, the development of powerful mathematical models tends to study tolerance limits and injury mechanisms in order to avoid experimental tests which cannot be easily conducted. In a military framework, developing a fighter/soldier numerical model can help to the understanding of many traumas which are specific to soldier injuries, like mines, ballistic impacts or blast traumas. The aim of this study is to investigate the consequences of violent loads in terms of human body response, submitting a developed and validated three-dimensional thorax finite element (FE) model to blast loadings. Specific formulations of FE methods are used to simulate this loading, and its consequence on the biomechanical model. Mechanical parameters such as pressure in the air field and also in internal organs are observed, and these values are compared to the experimental data in the literature. This study gives encouraging results and allows going further in soldier trauma investigations. Copyright © 2014 John Wiley & Sons, Ltd.

  1. Amputee locomotion: lower extremity loading using running-specific prostheses.

    Science.gov (United States)

    Hobara, Hiroaki; Baum, Brian S; Kwon, Hyun-Joon; Linberg, Alison; Wolf, Erik J; Miller, Ross H; Shim, Jae Kun

    2014-01-01

    Carbon fiber running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEA) to actively participate in sporting activities including competitive sports. In spite of this positive trait, the RSPs have not been thoroughly evaluated regarding potential injury risks due to abnormal loading during running. Vertical impact peak (VIP) and average loading rate (VALR) of the vertical ground reaction force (vGRF) have been associated with running injuries in able-bodied runners but not for ILEA. The purpose of this study was to investigate vGRF loading in ILEA runners using RSPs across a range of running speeds. Eight ILEA with unilateral transtibial amputations and eight control subjects performed overground running at three speeds (2.5, 3.0, and 3.5m/s). From vGRF, we determined VIP and VALR, which was defined as the change in force divided by the time of the interval between 20 and 80% of the VIP. We observed that VIP and VALR increased in both ILEA and control limbs with an increase in running speed. Further, the VIP and VALR in ILEA intact limbs were significantly greater than ILEA prosthetic limbs and control subject limbs for this range of running speeds. These results suggest that (1) loading variables increase with running speed not only in able-bodied runners, but also in ILEA using RSPs, and (2) the intact limb in ILEA may be exposed to a greater risk of running related injury than the prosthetic limb or able-bodied limbs. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Cervical spine injury biomechanics: Applications for under body blast loadings in military environments.

    Science.gov (United States)

    Yoganandan, Narayan; Stemper, Brian D; Pintar, Frank A; Maiman, Dennis J; McEntire, B Joseph; Chancey, Valeta Carol

    2013-07-01

    While cervical spine injury biomechanics reviews in motor vehicle and sports environments are available, there is a paucity of studies in military loadings. This article presents an analysis on the biomechanics and applications of cervical spine injury research with an emphasis on human tolerance for underbody blast loadings in the military. Following a brief review of published military studies on the occurrence and identification of field trauma, postmortem human subject investigations are described using whole body, intact head-neck complex, osteo-ligamentous cervical spine with head, subaxial cervical column, and isolated segments subjected to differing types of dynamic loadings (electrohydraulic and pendulum impact devices, free-fall drops). Spine injuries have shown an increasing trend over the years, explosive devices are one of the primary causal agents and trauma is attributed to vertical loads. Injuries, mechanisms and tolerances are discussed under these loads. Probability-based injury risk curves are included based on loading rate, direction and age. A unique advantage of human cadaver tests is the ability to obtain fundamental data to delineate injury biomechanics and establish human tolerance and injury criteria. Definitions of tolerances of the spine under vertical loads based on injuries have implications in clinical and biomechanical applications. Primary outputs such as forces and moments can be used to derive secondary variables such as the neck injury criterion. Implications are discussed for designing anthropomorphic test devices that may be used to predict injuries in underbody blast environments and improve the safety of military personnel. Published by Elsevier Ltd.

  3. Reducing Structural Weight and Increasing Protection in Simple Structures Subjected to Blast Loads

    Science.gov (United States)

    2014-08-12

    compression measured in the spring, which is determined from the governing equations shown in Appendix A. In the LS-DYNA model, a single spring- mass - damper ...like a solid when experiencing a large shear load, such as an impulse of high pressure but of short duration from a blast, and returns to liquid ... mass model with a single degree of freedom (DOF) representing the upper torso of the occupant (Appendix A) is mounted directly in the middle of the

  4. Further Study on Strain Growth in Spherical Containment Vessels Subjected to Internal Blast Loading

    OpenAIRE

    2009-01-01

    Abstract Strain growth is a phenomenon observed in the elastic response of containment vessels subjected to internal blast loading, which is featured by the increased vibration amplitude of the vessel in a later stage. Previous studies attributed the strain growth in spherical containment vessels to the beating between two close vibration modes, the interactions between the vessel vibration and the reflected shock waves and the structural perturbation. In this paper, it is shown th...

  5. Variability of extreme flap loads during turbine operation

    Energy Technology Data Exchange (ETDEWEB)

    Ronold, K.O. [Det Norske Veritas, Hoevik (Norway); Larsen, G.C. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The variability of extreme flap loads is of utmost importance for design of wind-turbine rotor blades. The flap loads of interest consist of the flap-wise bendin moment response at the blade root whose variability in the short-term, for a given wind climate, can be represented by a stationary process. A model for the short-term bending moment process is presented, and the distribution of its associated maxima is derived. A model for the wind climate is given in terms of the probability distributions for the 10-minute mean wind speed and the standard deviation of the arbitrary wind speed. This is used to establish the distribution of the largest flap-wise bending moment in a specific reference period, and it is outlined how a characteristic bending moment for use in design can be extracted from this distribution. The application of the presented distribution models is demonstrated by a numerical example for a site-specific wind turbine. (au)

  6. Influence of steel fibers on the shear and flexural performance of high-strength concrete beams tested under blast loads

    Science.gov (United States)

    Algassem, O.; Li, Y.; Aoude, H.

    2017-09-01

    This paper presents the results of a study examining the effect of steel fibres on the blast behaviour of high-strength concrete beams. As part of the study, a series of three large-scale beams built with high-strength concrete and steel fibres are tested under simulated blast loading using the shock-tube testing facility at the University of Ottawa. The specimens include two beams built with conventional high-strength concrete (HSC) and one beam built with high-strength concrete and steel fibres (HSFRC). The effect of steel fibres on the blast behaviour is examined by comparing the failure mode, mid-span displacements and, overall blast resistance of the specimens. The results show that the addition of steel fibres in high-strength concrete beams can prevent shear failure and substitute for shear reinforcement if added in sufficient quantity. Moreover, the use of steel fibres improves flexural response under blast loading by reducing displacements and increasing blast capacity. Finally, the provision of steel fibres is found to improve the fragmentation resistance of high-strength concrete under blast loads.

  7. Partitioning of a scaled shallow-buried near-field blast load

    CSIR Research Space (South Africa)

    Reinecke, J David

    2015-07-01

    Full Text Available the simple momentum of the soil cap indicating that a more complex loading is present and the initial force phase impulse contribution is more. This implies that the target force response morphology is affected by the DOB and SOD. CONCLUSIONS A research.... 16-26. DENIS M. BERGERON, D.M., HLADY, S.L. and BRAID, M.P., 2002. Pendulum Technique to Measure Land Mine Blast Loading. DESHPANDE, V.S., MCMEEKING, R.M., WADLEY, H.N.G. and EVANS, A.G., Constitutive Model for Predicting dynamic interactions...

  8. Design of Blast-Loaded Glazing Windows and Facades: A Review of Essential Requirements towards Standardization

    Directory of Open Access Journals (Sweden)

    Martin Larcher

    2016-01-01

    Full Text Available The determination of the blast protection level of laminated glass windows and facades is of crucial importance, and it is normally done by using experimental investigations. In recent years numerical methods have become much more powerful also with respect to this kind of application. This paper attempts to give a first idea of a possible standardization concerning such numerical simulations. Attention is drawn to the representation of the blast loading and to the proper description of the behaviour of the material of the mentioned products, to the geometrical meshing, and to the modelling of the connections of the glass components to the main structure. The need to validate the numerical models against reliable experimental data, some of which are indicated, is underlined.

  9. Full-scale testing and numerical modeling of a multistory masonry structure subjected to internal blast loading

    Science.gov (United States)

    Zapata, Brian Jarvis

    As military and diplomatic representatives of the United States are deployed throughout the world, they must frequently make use of local, existing facilities; it is inevitable that some of these will be load bearing unreinforced masonry (URM) structures. Although generally suitable for conventional design loads, load bearing URM presents a unique hazard, with respect to collapse, when exposed to blast loading. There is therefore a need to study the blast resistance of load bearing URM construction in order to better protect US citizens assigned to dangerous locales. To address this, the Department of Civil and Environmental Engineering at the University of North Carolina at Charlotte conducted three blast tests inside a decommissioned, coal-fired, power plant prior to its scheduled demolition. The power plant's walls were constructed of URM and provided an excellent opportunity to study the response of URM walls in-situ. Post-test analytical studies investigated the ability of existing blast load prediction methodologies to model the case of a cylindrical charge with a low height of burst. It was found that even for the relatively simple blast chamber geometries of these tests, simplified analysis methods predicted blast impulses with an average net error of 22%. The study suggested that existing simplified analysis methods would benefit from additional development to better predict blast loads from cylinders detonated near the ground's surface. A hydrocode, CTH, was also used to perform two and three-dimensional simulations of the blast events. In order to use the hydrocode, Jones Wilkins Lee (JWL) equation of state (EOS) coefficients were developed for the experiment's Unimax dynamite charges; a novel energy-scaling technique was developed which permits the derivation of new JWL coefficients from an existing coefficient set. The hydrocode simulations were able to simulate blast impulses with an average absolute error of 34.5%. Moreover, the hydrocode simulations

  10. The Effects of Load Carriage and Muscle Fatigue on Lower-Extremity Joint Mechanics

    Science.gov (United States)

    Wang, He; Frame, Jeff; Ozimek, Elicia; Leib, Daniel; Dugan, Eric L.

    2013-01-01

    Military personnel are commonly afflicted by lower-extremity overuse injuries. Load carriage and muscular fatigue are major stressors during military basic training. Purpose: To examine effects of load carriage and muscular fatigue on lower-extremity joint mechanics during walking. Method: Eighteen men performed the following tasks: unloaded…

  11. Effect of Large Negative Phase of Blast Loading on Structural Response of RC Elements

    Directory of Open Access Journals (Sweden)

    Syed Zubair Iman

    2016-01-01

    Full Text Available Structural response of reinforced concrete (RC elements for analysis and design are often obtained using the positive phase of the blast pressure curve disregarding the negative phase assuming insignificant contribution from the negative phase of the loading. Although, some insight on the effect of negative phase of blast pressure based on elastic single-degree-of-freedom (SDOF analysis was presented before, the influence of negative phase on different types of resistance functions of SDOF models and on realistic finite element analysis has not been explored. In this study, the effects of inclusion of pulse negative phase on structural response of RC elements from SDOF analysis and from more detailed finite element analysis have been investigated. Investigation of SDOF part has been conducted using MATLAB code that utilizes non-linear resistance functions of SDOF model. Detailed numerical investigation using finite element code DIANA was conducted on the significance of the negative phase on structural response. In the FE model, different support stiffness was used to explore the effect of support stiffness on the structural response due to blast negative phase. Results from SDOF and FE analyses present specific situations where the effect of large negative phase was found to be significant on the structural response of RC elements.

  12. A simple coupling of ALE domain with empirical blast load function in LS-DYNA

    Science.gov (United States)

    Gilson, L.; Van Roey, J.; Guéders, C.; Gallant, J.; Rabet, L.

    2012-08-01

    Blast effects on structures are of great interest both in the civilian and military domain. This fact leads to the need of the development of simple and efficient simulation methods. The two common and most used methods have a very different philosophy. The first one is the construction of a full Eulerian domain containing both the detonating charge and the sollicitated structure. An inconvenience of this method is the very long duration of the simulation since the entire external domain is modelled, especially if the charge-structure distance is very large. The second method is the direct application of the corresponding loading based on empirical data (from ConWep) to the structure without simulating the external domain. Although this method allows a consequent time benefit, it has also some disadvantages such as the fact that shadowing, ground reflection and side effects are not taken into account. Moreover, every structure is considered as rigid since the load directly applied is the reflected pressure from ConWep's database, which gives only the reflected pressure in a rigid case. This can be a problem for the application of blast loading on elastic, low-impedance materials such as granular materials or even on small density structures that are able to have a non-negligible displacement during the positive phase duration of the loading. Material impedance and structure displacement might alter the shockwave-structure interaction. A new method using both philosophies has been developed by Slavik [2]. In this method, an Arbitrary Lagrangian-Eulerian mesh (ALE) is created only around the structure in which the empirical incident pressure is applied. The loading is applied onto the air domain, propagates to the structure and interacts with this structure. At this time, the material parameters of the structure and its displacement are taken into account. This paper aims to evaluate third method's capabilities. Moreover, it studies the influence of structure

  13. Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams

    Directory of Open Access Journals (Sweden)

    Zhenyu Wang

    2013-01-01

    Full Text Available Carbon fiber-reinforced polymer composites (CFRPs are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.

  14. Mechanics of blast loading on the head models in the study of traumatic brain injury using experimental and computational approaches.

    Science.gov (United States)

    Ganpule, S; Alai, A; Plougonven, E; Chandra, N

    2013-06-01

    Blast waves generated by improvised explosive devices can cause mild, moderate to severe traumatic brain injury in soldiers and civilians. To understand the interactions of blast waves on the head and brain and to identify the mechanisms of injury, compression-driven air shock tubes are extensively used in laboratory settings to simulate the field conditions. The overall goal of this effort is to understand the mechanics of blast wave-head interactions as the blast wave traverses the head/brain continuum. Toward this goal, surrogate head model is subjected to well-controlled blast wave profile in the shock tube environment, and the results are analyzed using combined experimental and numerical approaches. The validated numerical models are then used to investigate the spatiotemporal distribution of stresses and pressure in the human skull and brain. By detailing the results from a series of careful experiments and numerical simulations, this paper demonstrates that: (1) Geometry of the head governs the flow dynamics around the head which in turn determines the net mechanical load on the head. (2) Biomechanical loading of the brain is governed by direct wave transmission, structural deformations, and wave reflections from tissue-material interfaces. (3) Deformation and stress analysis of the skull and brain show that skull flexure and tissue cavitation are possible mechanisms of blast-induced traumatic brain injury.

  15. Multivariate Modelling of Extreme Load Combinations for Wind Turbines

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    2015-01-01

    We demonstrate a model for estimating the joint probability distribution of two load components acting on a wind turbine blade cross section. The model addresses the problem of modelling the probability distribution of load time histories with large periodic components by dividing the signal...

  16. A Novel Online Sequential Extreme Learning Machine for Gas Utilization Ratio Prediction in Blast Furnaces

    Directory of Open Access Journals (Sweden)

    Yanjiao Li

    2017-08-01

    Full Text Available Gas utilization ratio (GUR is an important indicator used to measure the operating status and energy consumption of blast furnaces (BFs. In this paper, we present a soft-sensor approach, i.e., a novel online sequential extreme learning machine (OS-ELM named DU-OS-ELM, to establish a data-driven model for GUR prediction. In DU-OS-ELM, firstly, the old collected data are discarded gradually and the newly acquired data are given more attention through a novel dynamic forgetting factor (DFF, depending on the estimation errors to enhance the dynamic tracking ability. Furthermore, we develop an updated selection strategy (USS to judge whether the model needs to be updated with the newly coming data, so that the proposed approach is more in line with the actual production situation. Then, the convergence analysis of the proposed DU-OS-ELM is presented to ensure the estimation of output weight converge to the true value with the new data arriving. Meanwhile, the proposed DU-OS-ELM is applied to build a soft-sensor model to predict GUR. Experimental results demonstrate that the proposed DU-OS-ELM obtains better generalization performance and higher prediction accuracy compared with a number of existing related approaches using the real production data from a BF and the created GUR prediction model can provide an effective guidance for further optimization operation.

  17. A Novel Online Sequential Extreme Learning Machine for Gas Utilization Ratio Prediction in Blast Furnaces.

    Science.gov (United States)

    Li, Yanjiao; Zhang, Sen; Yin, Yixin; Xiao, Wendong; Zhang, Jie

    2017-08-10

    Gas utilization ratio (GUR) is an important indicator used to measure the operating status and energy consumption of blast furnaces (BFs). In this paper, we present a soft-sensor approach, i.e., a novel online sequential extreme learning machine (OS-ELM) named DU-OS-ELM, to establish a data-driven model for GUR prediction. In DU-OS-ELM, firstly, the old collected data are discarded gradually and the newly acquired data are given more attention through a novel dynamic forgetting factor (DFF), depending on the estimation errors to enhance the dynamic tracking ability. Furthermore, we develop an updated selection strategy (USS) to judge whether the model needs to be updated with the newly coming data, so that the proposed approach is more in line with the actual production situation. Then, the convergence analysis of the proposed DU-OS-ELM is presented to ensure the estimation of output weight converge to the true value with the new data arriving. Meanwhile, the proposed DU-OS-ELM is applied to build a soft-sensor model to predict GUR. Experimental results demonstrate that the proposed DU-OS-ELM obtains better generalization performance and higher prediction accuracy compared with a number of existing related approaches using the real production data from a BF and the created GUR prediction model can provide an effective guidance for further optimization operation.

  18. Lumbar spine loads during the lifting of extremely heavy weights.

    Science.gov (United States)

    Cholewicki, J; McGill, S M; Norman, R W

    1991-10-01

    The reaction moments at the knee, hip, and L4/L5 joints, and the compressive and shearing forces on L4/L5 are documented in powerlifters competing in a national powerlifting championship. Analyses were made of 13 female and 44 male competitors. The joint moments and forces were estimated from a linked segment model (WATBAK) that incorporated functional low back extensor musculature with a moment arm of 6 cm and a line action that was oriented 5 degrees posteriorly to the L4/L5 compression axis. This oblique orientation of the extensor muscles reduced the anterior shearing load on the vertebral motion unit. Average compressive loads on L4/L5 were estimated up to 17,192 N while the highest average L4/L5 and hip moments were 988 and 1047 N.m, respectively. The sumo deadlift style resulted in a 10% reduction in the joint moment and 8% reduction in the load shear force at the L4/L5 level when compared with the conventional lifting style. Formulation of linear regression equations to predict the load lifted using reaction joint moments yielded substantial unexplained variability, though significant relationships were found. This analysis suggested that there is large variability in the pattern of loading joints among national class powerlifters.

  19. Probability Assessment and Risk Management of Progressive Collapse in Strategic Buildings Facing Blast Loads

    Directory of Open Access Journals (Sweden)

    Gholamreza Abdollahzadeh

    2016-12-01

    Full Text Available Nowadays, as a result of increased terrorist and bomb attacks throughout the globe in the vicinity of strategic buildings, designing these structures against impact loads, particularly the blast-related ones, has been taken into more consideration. The current procedure for designing the structure against an explosion is a design against the local failure of the current elements in the first step and then, in the next step, against local damage as well as tactful thinking to prevent this damage from spreading to other parts of the structure. The present research investigates the impacts of explosives, derived from probable terror–stricken scenarios inside and outside a strategic four-story steel building with a special moment frame system. Then, the resistive capacity of the damaged building (due to blast has been evaluated against the progressive collapse, and finally, the rate of the collapse risk and the reliability of the structure have been obtained by presenting a probable method. Thus, the vulnerable parts inside and outside the building are identified and safety measures have been determined, so that in case of no safety or excessive collapse risk- access to dangerous parts of the building could be reinforced or limited. Results show that progressive collapse probability and reliability of the building are 57% and 43% respectively.

  20. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Candice Frances [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burnett, Damon J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is virtually nonexistent but necessary to ensure adequate protection against injury to the heart and lungs. In this report, we discuss the development of a high-fidelity human torso model, it's merging with the existing Sandia Human Head-Neck Model, and development of the modeling & simulation (M&S) capabilities necessary to simulate wound injury scenarios. Using the new Sandia Human Torso Model, we demonstrate the advantage of virtual simulation in the investigation of wound injury as it relates to the warfighter experience. We present the results of virtual simulations of blast loading and ballistic projectile impact to the tors o with and without notional protective armor. In this manner, we demonstrate the ad vantages of applying a modeling and simulation approach to the investigation of wound injury and relative merit assessments of protective body armor without the need for trial-and-error testing.

  1. A method to find the 50-year extreme load during production

    NARCIS (Netherlands)

    Bos, R.; Veldkamp, D.

    2016-01-01

    An important yet difficult task in the design of wind turbines is to assess the extreme load behaviour, most notably finding the 50-year load. Where existing methods often focus on ways to extrapolate from small sample sizes, this paper proposes a different approach. It combines generating

  2. Vertical accelerator device to apply loads simulating blast environments in the military to human surrogates.

    Science.gov (United States)

    Yoganandan, Narayan; Pintar, Frank A; Schlick, Michael; Humm, John R; Voo, Liming; Merkle, Andrew; Kleinberger, Michael

    2015-09-18

    The objective of the study was to develop a simple device, Vertical accelerator (Vertac), to apply vertical impact loads to Post Mortem Human Subject (PMHS) or dummy surrogates because injuries sustained in military conflicts are associated with this vector; example, under-body blasts from explosive devices/events. The two-part mechanically controlled device consisted of load-application and load-receiving sections connected by a lever arm. The former section incorporated a falling weight to impact one end of the lever arm inducing a reaction at the other/load-receiving end. The "launch-plate" on this end of the arm applied the vertical impact load/acceleration pulse under different initial conditions to biological/physical surrogates, attached to second section. It is possible to induce different acceleration pulses by using varying energy absorbing materials and controlling drop height and weight. The second section of Vertac had the flexibility to accommodate different body regions for vertical loading experiments. The device is simple and inexpensive. It has the ability to control pulses and flexibility to accommodate different sub-systems/components of human surrogates. It has the capability to incorporate preloads and military personal protective equipment (e.g., combat helmet). It can simulate vehicle roofs. The device allows for intermittent specimen evaluations (x-ray and palpation, without changing specimen alignment). The two free but interconnected sections can be used to advance safety to military personnel. Examples demonstrating feasibilities of the Vertac device to apply vertical impact accelerations using PMHS head-neck preparations with helmet and booted Hybrid III dummy lower leg preparations under in-contact and launch-type impact experiments are presented. Published by Elsevier Ltd.

  3. An examination of blast and impulse effects from the metal loading of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Victor E [Los Alamos National Laboratory; Zucker, Jonathan M [Los Alamos National Laboratory; Mc Afee, John M [Los Alamos National Laboratory; Tappan, Bryce C [Los Alamos National Laboratory; Asay, Blaine W [Los Alamos National Laboratory

    2010-01-01

    Explosive compositions loaded with various metal particulates were produced and tested using a unique experimental configuration. The high explosive HMX was used as the standard and was tested over a range of mass loading fractions using tungsten and tantalum as metal additives. The diagnostics used in this set of experiments included free-field blast sensors, dynamic force sensors, time-of-arrival sensors, and a high-speed digital camera. The experimental arrangement allowed for concurrent spatial measurements of the static pressure from expanding gaseous detonation products, along with the total force from the combination of gaseous products and solid particles. The total pressure from the multi-phase products was calculated by measuring the total force applied to the surface of a newly developed force sensor. The results from the force sensor and other measurement techniques were validated against existing numerical methods. The relationship between static and dynamic pressures as a function of metal loading fraction was examined empirically at several distances from the charge for two distinct metal additives.

  4. Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.

    Energy Technology Data Exchange (ETDEWEB)

    Fitzwater, LeRoy M. (Stanford University, Stanford, CA)

    2004-01-01

    An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.

  5. Mercury loads into the sea associated with extreme flood.

    Science.gov (United States)

    Saniewska, Dominika; Bełdowska, Magdalena; Bełdowski, Jacek; Jędruch, Agnieszka; Saniewski, Michał; Falkowska, Lucyna

    2014-08-01

    Floods are an important factor determining riverine pollution loads, including toxic mercury (Hg). The impact of the Vistula River flood in 2010, which was the biggest one recorded in 160 years and its influence on marine environment was studied. Mercury concentration was analyzed in river and sea water, suspended matter, phytoplankton and sea surface sediment. Flood and gulf water contained several times higher concentration of Hg (exceeded reference values safe for aquatic organisms) than before or after the flood. In 2010 the Vistula introduced into the Baltic ca. 1576 kg of Hg, of which 75% can be attributed to the flood water. Increase of water temperature, decrease of oxygen content contended increasing of dissolved mercury concentration, which was transported far into the Baltic. This phenomenon led to an increase of Hg concentration in phytoplankton and during many months in surface sediments. It is a potential threat to marine organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Mechanical Characterization and Finite Element Implementation of the SoftMaterials used in a Novel Anthropometric Test Device for SimulatingUnderbody Blast Loading

    Science.gov (United States)

    2017-09-14

    Materials used in a Novel Anthropometric Test Device for Simulating Underbody Blast Loading by Wade A Baker, Costin D Untaroiu, Dawn M Crawford, and...used in a Novel Anthropometric Test Device for Simulating Underbody Blast Loading by Wade A Baker and Costin D Untaroiu Virginia Tech, Department...SUBTITLE Mechanical Characterization and Finite Element Implementation of the Soft Materials used in a Novel Anthropometric Test Device for

  7. VISAR fringe analysis under extreme spatially varying shock loading

    Science.gov (United States)

    Erskine, David; Fratanduono, Dayne

    2017-06-01

    Many VISAR velocity interferometers employ a streak camera to record fringes along the spatial axis (Y) of a target, versus time. When the shock loading (thus velocity history) varies rapidly versus Y, the fringe analysis challenges traditional algorithms since the Y-spacing of fringes can vary strongly with Y, and be significantly different than the uniform pre-shock (bias) spacing. For traditional colum-by-column analysis the intensity signal shape would be a sinusoid with rapidly varying frequency (chirped), which can confuse a traditional algorithm expecting a monochromatic peak in Fourier space. And for a traditional push-pull row-by-row approach, the phase steps are irregular. We describe preliminary success in analyzing such data in simulation. We find it useful to (a) separate the nonfringing component from the data early; (b) maximize linearity of a plot of fringing magnitude versus nonfringing intensity to choose optimal weight values; (c) when using a row-by-row approach sampling 0, 90, 180, and 270 degrees phase we add a fifth sample at 360 degrees, which is averaged with the 0 degree sample and replaces it. This increases the robustness to variable phase step (following P. Hariharan). The pre-shock and post-shock regions are separately processed/concatenated. Prepared by LLNL under Contract DE-AC52-07NA27344.

  8. Tensile characterisation of the aorta across quasi-static to blast loading strain rates

    Science.gov (United States)

    Magnus, Danyal; Proud, William; Haller, Antoine; Jouffroy, Apolline

    2017-06-01

    The dynamic tensile failure mechanisms of the aorta during Traumatic Aortic Injury (TAI) are poorly understood. In automotive incidents, where the aorta may be under strains of the order of 100/s, TAI is the second largest cause of mortality. In these studies, the proximal descending aorta is the most common site where rupture is observed. In particular, the transverse direction is most commonly affected due to the circumferential orientation of elastin, and hence the literature generally concentrates upon axial samples. This project extends these dynamic studies to the blast loading regime where strain-rates are of the order of 1000/s. A campaign of uniaxial tensile experiments are conducted at quasi-static, intermediate (drop-weight) and high (tensile Split-Hopkinson Pressure Bar) strain rates. In each case, murine and porcine aorta models are considered and the extent of damage assessed post-loading using histology. Experimental data will be compared against current viscoelastic models of the aorta under axial stress. Their applicability across strain rates will be discussed. Using a multi-disciplinary approach, the conditions applied to the samples replicate in vivo conditions, employing a blood simulant-filled tubular specimen surrounded by a physiological solution.

  9. Numerical Analysis of Dynamic Response of Corrugated Core Sandwich Panels Subjected to Near-Field Air Blast Loading

    Directory of Open Access Journals (Sweden)

    Pan Zhang

    2014-01-01

    Full Text Available Three-dimensional fully coupled simulation is conducted to analyze the dynamic response of sandwich panels comprising equal thicknesses face sheets sandwiching a corrugated core when subjected to localized impulse created by the detonation of cylindrical explosive. A large number of computational cases have been calculated to comprehensively investigate the performance of sandwich panels under near-field air blast loading. Results show that the deformation/failure modes of panels depend strongly on stand-off distance. The beneficial FSI effect can be enhanced by decreasing the thickness of front face sheet. The core configuration has a negligible influence on the peak reflected pressure, but it has an effect on the deflection of a panel. It is found that the benefits of a sandwich panel over an equivalent weight solid plate to withstand near-field air blast loading are more evident at lower stand-off distance.

  10. A Method of Selecting the Block Size of BMM for Estimating Extreme Loads in Engineering Vehicles

    Directory of Open Access Journals (Sweden)

    Jixin Wang

    2016-01-01

    Full Text Available Extreme loads have a significant effect on the fatigue damage of components. The block maximum method (BMM is widely used to estimate extreme values in various fields. Selecting a reasonable block size for BMM is crucial to ensure that proper extreme values are extracted to get extreme sample to estimate extreme values. Aiming at this issue, this study proposed a comprehensive evaluation approach based on multiple-criteria decision making (MCDM method to select a proper block size. A wheel loader with six sections in one operating cycle was illustrated as an example. First, spading sections of each operating cycle were extracted and connected as extreme loads often occur at that section. Then extreme sample was obtained by BMM for fitting the generalized extreme value (GEV distribution. Kolmogorov-Smirnov (K-S test, Pearson’s Chi-Square (χ2 test, and average deviation in Probability Distribution Function (PDF are selected as the fitting test. The comprehensive weights are calculated by the maximum entropy principle. Finally, the optimal block size corresponding to the minimum comprehensive evaluation indicator is obtained and the result exhibited a good fitting effect. The proposed method can also be flexibly used in various situations to select a block size.

  11. Monte Carlo Simulation of Extreme Traffic Loading on Short and Medium Span Bridges

    OpenAIRE

    ENRIGHT, Bernard; O'Brien, Eugene J.

    2012-01-01

    The accurate estimation of site-specific lifetime extreme traffic load effects is an important element in the cost-effective assessment of bridges. A common approach is to use statistical distributions derived from weigh-in-motion measurements as the basis for Monte Carlo simulation of traffic loading. However, results are highly sensitive to the assumptions made, not just with regard to vehicle weights but also to axle configurations and gaps between vehicles. This paper presents a comprehen...

  12. Wave loads for ships/marine structures -Stochastic procedures for extreme load predictions

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2008-01-01

    A discussion of useful stochastic procedures for stochastic wave load problems is given, covering the range from slightly linear to strongly non-linear (bifurcation) problems. The methods are: Hermite transformation, Critical wave episodes and the First Order Reliability Method (FORM). The proced......A discussion of useful stochastic procedures for stochastic wave load problems is given, covering the range from slightly linear to strongly non-linear (bifurcation) problems. The methods are: Hermite transformation, Critical wave episodes and the First Order Reliability Method (FORM......). The procedures will be illustrated by results for the wave bending moment in ships, parametric rolling of a ship and the overturning of a jack-up rig....

  13. Stochastic Procedures for Extreme Wave Load Predictions- Wave Bending Moment in Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2009-01-01

    A discussion of useful stochastic procedures for stochastic wave load problems is given, covering the range from slightly linear to strongly non-linear (bifurcation) problems. The methods are: Hermite transformation, Critical wave episodes and the First Order Reliability Method (FORM). The proced......). The procedures will be illustrated by results for the extreme vertical wave bending moment in ships....

  14. Predicting extreme loads effects on wind turbines considering uncertainty in airfoil data

    DEFF Research Database (Denmark)

    Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

    2013-01-01

    The sources contributing to uncertainty in a wind turbine blade static airfoil data include wind tunnel testing, CFD calculations, 3D rotational corrections based on CFD or empirical models, surface roughness corrections, Reynolds number corrections, expansion to the full 360-degree angle of attack...... that the uncertainty in airfoil data can have a significant impact on the prediction of extreme loads effects depending on the component, and the correlation along the span of the blade....... range, validation by full scale measurements, and geometric distortions of the blade during manufacturing and under loading. In this paper a stochastic model of the static airfoil data is proposed to supplement the prediction of extreme loads effects for large wind turbines. It is shown...

  15. Predicting the Extreme Loads on a Wind Turbine Considering Uncertainty in Airfoil Data

    DEFF Research Database (Denmark)

    Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

    2014-01-01

    The sources contributing to uncertainty in a wind turbine blade static airfoil data include wind tunnel testing, CFD calculations, 3D rotational corrections based on CFD or emprircal models, surface roughness corrections, Reynolds number corrections, expansion to the full 360-degree angle of attack...... that the uncertainty in airfoil data can have e significant impact on the prediction of extreme loads effects depending on the component, and the correlation along the span of the blade....... range, validation by full scale measurements, and geometric distortions of the blade during manufacturing and under loading. In this paper a stochastic model of the static airfoil data is proposed to supplement the prediction of extreme loads effects for large wind turbines. It is shown...

  16. Single and multi degree of freedom analysis of steel beams under blast loading

    Energy Technology Data Exchange (ETDEWEB)

    Nassr, Amr A., E-mail: nassraa@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Razaqpur, A. Ghani, E-mail: razaqpu@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Tait, Michael J., E-mail: taitm@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Campidelli, Manuel, E-mail: campide@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Foo, Simon, E-mail: simon.foo@pwgsc.gc.ca [Public Works and Government Services, Gatineau, Quebec (Canada)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Experimentally tested beams under blast are analyzed using SDOF and MDOF models. Black-Right-Pointing-Pointer SDOF model adequately captures the time dependant deformations and internal forces. Black-Right-Pointing-Pointer Constant DIF based on a low strain rate leads to conservative estimate of the DIF. Black-Right-Pointing-Pointer The responses of the test beams are governed by the first mode of vibration. - Abstract: This paper presents detailed analysis of the results of field tests on 13 full scale wide flange steel beams subjected to blast loads generated by the detonation of up to 250 kg of ANFO explosive. The experimental results are analyzed using an equivalent Single-Degree-of-Freedom (SDOF) model of a beam, which includes material nonlinearity and strain rate effects. To account for strain rate effect on beam stiffness and strength, its full moment-curvature response is determined by dividing its cross-section into a number of layers and a strain rate-dependent stress-strain relationship, based on the Cowper-Symonds strain rate model, is used to capture the nonlinear stress distribution over the section. To determine the effects of higher modes of vibration and the variation of beam mechanical properties along its length on its dynamic response, the test beams are also analyzed using a Multi-Degree-of-Freedom (MDOF) model involving beam finite elements. Each element has two nodes and three degrees of freedom and is again divided into a number of layers to capture the strain rate effect and nonlinear stress distribution over its depth. The predicted displacements and strains by the two models are compared with the corresponding experimental data and the results show that for the given beams, the time-dependant deformations, internal forces, and moments can be adequately predicted by either model because the first mode of vibration is found to dominate their response; however, the use of a constant strain rate

  17. Analysis of Glenoid Fixation with Anatomic Total Shoulder Arthroplasty in an Extreme Cyclic Loading Scenario.

    Science.gov (United States)

    Roche, Christopher P; Staunch, Cameron; Hahn, William; Grey, Sean G; Flurin, Pierre-Henri; Wright, Thomas W; Zuckerman, Joseph D

    2015-12-01

    of fatigue-related failures in these elevated load and high cycle test scenarios are promising, as are the relatively low displacements given the extreme nature of each test. This cyclic loading method is intended to supplement the ASTM F2028-14 standard that adequately simulates the rocking horse loading mechanism but may not adequately simulate the fatigue-related failure modes.

  18. Advances in the Assessment of Wind Turbine Operating Extreme Loads via More Efficient Calculation Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Peter; Damiani, Rick R.; Dykes, Katherine; Jonkman, Jason M.

    2017-01-09

    A new adaptive stratified importance sampling (ASIS) method is proposed as an alternative approach for the calculation of the 50 year extreme load under operational conditions, as in design load case 1.1 of the the International Electrotechnical Commission design standard. ASIS combines elements of the binning and extrapolation technique, currently described by the standard, and of the importance sampling (IS) method to estimate load probability of exceedances (POEs). Whereas a Monte Carlo (MC) approach would lead to the sought level of POE with a daunting number of simulations, IS-based techniques are promising as they target the sampling of the input parameters on the parts of the distributions that are most responsible for the extreme loads, thus reducing the number of runs required. We compared the various methods on select load channels as output from FAST, an aero-hydro-servo-elastic tool for the design and analysis of wind turbines developed by the National Renewable Energy Laboratory (NREL). Our newly devised method, although still in its infancy in terms of tuning of the subparameters, is comparable to the others in terms of load estimation and its variance versus computational cost, and offers great promise going forward due to the incorporation of adaptivity into the already powerful importance sampling concept.

  19. Extreme Loads on the Mooring Lines and Survivability Mode for the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Kofoed, Jens Peter; Friis-Madsen, E.

    2011-01-01

    One of the main challenges Wave Energy Converters have to face on the road towards commercialization is to ensure survivability in extreme condition at a reasonable capital costs. For a floating device like the Wave Dragon, a reliable mooring system is essential. The control strategy of the Wave...... Dragon aims at optimizing the power production by adapting the floating level to the incoming waves and by activating the hydro-turbines and regulating their working speed. In extreme conditions though, the control strategy could be changed in order to reduce the forces in the mooring system, lowering...... the design requirements with almost no added cost. The paper presents the result of the tank testing of a 1:51.8 scale model of a North Sea Wave Dragon in extreme wave conditions of up to 100 years of return period. The results show that the extreme loads in the main mooring line can be reduced...

  20. Extreme Design Loads Calibration of Offshore Wind Turbine Blades through Real Time Measurements

    DEFF Research Database (Denmark)

    Natarajan, Anand; Vesth, Allan; Lamata, Rebeca Rivera

    2014-01-01

    Blade Root flap and Edge moments are measured on the blades of a 3.6MW offshore wind turbine in normal operation. Ten minute maxima of the measurements are sampled to determine the extreme blade root flap moment, edge moment and resultant moment over six month duration. A random subset of the mea...... moment is extrapolated. This is found to possess smaller scaling factors in measurements over six months as compared to both the flap and edge moments, indicating that the contemporaneous load component of an extrapolated load should possess much smaller magnitude than its maxima....

  1. Extreme Design Loads Calibration of Offshore Wind Turbine Blades through Real Time Measurements

    DEFF Research Database (Denmark)

    Natarajan, Anand; Vesth, Allan; Lamata, Rebeca Rivera

    Blade Root flap and Edge moments are measured on the blades of a 3.6MW offshore wind turbine in normal operation. Ten minute maxima of the measurements are sampled to determine the extreme blade root flap moment, edge moment and resultant moment over six month duration. A random subset of the mea...... moment is extrapolated. This is found to possess smaller scaling factors in measurements over six months as compared to both the flap and edge moments, indicating that the contemporaneous load component of an extrapolated load should possess much smaller magnitude than its maxima....

  2. Modelling the behaviour of composite sandwich structures when subject to air-blast loading

    Directory of Open Access Journals (Sweden)

    H Arora

    2016-09-01

    Full Text Available Large-scale glass fibre reinforced polymer (GFRP and carbon fibre reinforced polymer (CFRP sandwich structures (1.6 m x 1.3 m were subject to explosive air blast (100 kg TNT equivalent at stand-off distances of 14 m. Digital image correlation (DIC was used to obtain full-field data for the rear-face of each deforming target. A steel plate of comparable mass per unit area was also subjected to the same blast conditions for comparison. The experimental data was then verified with finite element models generated in Abaqus/Explicit. Close agreement was obtained between the numerical and experimental results, confirming that the CFRP panels had a superior blast performance to the GFRP panels. Moreover all composite targets sustained localised failures (that were more severe in the GFRP targets but retained their original shape post blast. The rear-skins remained intact for each composite target with core shear failure present.

  3. Deterministic and Probabilistic Analysis of NPP Communication Bridge Resistance Due to Extreme Loads

    Directory of Open Access Journals (Sweden)

    Králik Juraj

    2014-12-01

    Full Text Available This paper presents the experiences from the deterministic and probability analysis of the reliability of communication bridge structure resistance due to extreme loads - wind and earthquake. On the example of the steel bridge between two NPP buildings is considered the efficiency of the bracing systems. The advantages and disadvantages of the deterministic and probabilistic analysis of the structure resistance are discussed. The advantages of the utilization the LHS method to analyze the safety and reliability of the structures is presented

  4. Investigating extreme event loading on coastal bridges using wireless sensor technology

    Science.gov (United States)

    Gelineau, Douglas A.; Davis, Justin R.; Rice, Jennifer A.

    2017-04-01

    Coastal infrastructure, such as bridges, are susceptible to many forms of coastal hazards: particularly hurricane surge and wave loading. These two forms of loading can cause catastrophic damage to aging highway infrastructure. It is estimated that storm damage costs the United States about $50 Billion per year. In light of this, it is crucial that we understand the damaging forces placed on infrastructure during storm events so that we can develop safer and more resilient coastal structures. This paper presents the ongoing research to enable the efficient collection of extreme event loads acting on both the substructure and superstructure of low clearance, simple span, reinforced concrete bridges. Bridges of this type were commonly constructed during the 1950's and 60's and are particularly susceptible to deck unseating caused by hurricane surge and wave loading. The sensing technology used to capture this data must be ruggedized to survive in an extremely challenging environment, be designed to allow for redundancy in the event of sensors or other network components being lost in the storm, and be relatively low cost to allow for more bridges to be instrumented per storm event. The prototype system described in this paper includes wireless technology, rapid data transmission, and, for the sensors, self-contained power. While this specific application focuses on hurricane hazards, the framework can be extended to include other natural hazards.

  5. Modelling poly(p-phenylene teraphthalamide) at Extreme Tensile Loading using Reactive Potentials

    Science.gov (United States)

    Yilmaz, Dundar

    2015-03-01

    Aromatic polyamides classified as rigid-rod polymers due to orientation of their monomers. Because of their excellent mechanical and thermal properties, aramids are widely used in the industry. For example DuPont's brand Kevlar, for its commercial aromatic polyamide polymer, due to wide usage of this polymer in ballistic applications, habitually used as a nickname for bulletproof vests. In order to engineer these ballistic fabrics, material properties of aramid fibers should be studied. In this work we focused on the poly(p-phenylene teraphthalamide) PPTA fiber, known as brand name Kevlar. We employed Reactive potentials to simulate PPTA polymer under tensile loading. We first simulated both amorphous and crystalline phases of PPTA. We also introduced defects with varying densities. We further analysed the recorded atomic positions data to understand how tensile load distributed and failure mechanisms at extreme tensile loads. This work supported by TUBITAK under Grant No: 113F358.

  6. Determination of three-dimensional joint loading within the lower extremities in snowboarding.

    Science.gov (United States)

    Krüger, Andreas; McAlpine, Paul; Borrani, Fabio; Edelmann-Nusser, Jürgen

    2012-02-01

    In the biomechanical literature only a few studies are available focusing on the determination of joint loading within the lower extremities in snowboarding. These studies are limited to analysis in a restricted capture volume due to the use of optical video-based systems. To overcome this restriction the aim of the present study was to develop a method to determine net joint moments within the lower extremities in snowboarding for complete measurement runs. An experienced snowboarder performed several runs equipped with two custom-made force plates as well as a full-body inertial measurement system. A rigid, multi-segment model was developed to describe the motion and loads within the lower extremities. This model is based on an existing lower-body model and designed to be run by the OpenSim software package. Measured kinetic and kinematic data were imported into the OpenSim program and inverse dynamic calculations were performed. The results illustrate the potential of the developed method for the determination of joint loadings within the lower extremities for complete measurement runs in a real snowboarding environment. The calculated net joint moments of force are reasonable in comparison to the data presented in the literature. A good reliability of the method seems to be indicated by the low data variation between different turns. Due to the unknown accuracy of this method the application for inter-individual studies as well as studies of injury mechanisms may be limited. For intra-individual studies comparing different snowboarding techniques as well as different snowboard equipment the method seems to be beneficial. The validity of the method needs to be studied further.

  7. Comparison of designing simple steel frame & coaxial brace systems by contrast of blast, using two methods of load & resistance coefficients & performance surfaces

    Directory of Open Access Journals (Sweden)

    P. Hassanvand

    2016-12-01

    Full Text Available Nowadays, because of the increasing terrorist attacks around the urban areas, designing buildings by contrast of resulted loads of blast came into consideration particularly in some sensitive buildings & vital arteries. When a blast occurs, the resulted emissions in environment leads to appearance of several penalties and endangers to the human life. Steel structures generally are designed on the basis of standard seismic and gravity loads, it is necessary to investigate the implantation of these structures under the impact of the loads originated from blast. This article presents numerical studies of two-dimensional structural models with 2 and 5 stories which are including simple steel frame system in addition to CBF. The models were analyzed by nonlinear dynamic analysis method using the instruction UFC 3-340-02 in two adverse levels of blast loads by SAP 2000 software. In this study structural models are designed and analyzed using two designing methods: the basic performance design, and Load and Resistance Factor Design (LRFD. Finally, two set of results are compared in detail.

  8. Influence of the control system on wind turbine loads during power production in extreme turbulence: Structural reliability

    DEFF Research Database (Denmark)

    Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

    2016-01-01

    The wind energy industry is continuously researching better computational models of wind inflow and turbulence to predict extreme loading (the nature of randomness) and their corresponding probability of occurrence. Sophisticated load alleviation control systems are increasingly being designed...... when advanced load alleviation control systems are used. We end by providing a rational comparison between the long term loads extrapolation method and the environmental contour method for the three control configurations. © 2015 Elsevier Ltd. All rights reserved....

  9. Non-linear Dynamic Analysis of Steel Hollow I-core Sandwich Panel under Air Blast Loading

    Directory of Open Access Journals (Sweden)

    Asghar Vatani Oskouei

    2015-12-01

    Full Text Available In this paper, the non-linear dynamic response of novel steel sandwich panel with hollow I-core subjected to blast loading was studied. Special emphasis is placed on the evaluation of midpoint displacements and energy dissipation of the models. Several parameters such as boundary conditions, strain rate, mesh dependency and asymmetrical loading are considered in this study. The material and geometric non-linearities are also considered in the numerical simulation. The results obtained are compared with available experimental data to verify the developed FE model. Modeling techniques are described in detail. According to the results, sandwich panels with hollow I-core allowed more plastic deformation and energy dissipation and less midpoint displacement than conventional I-core sandwich panels and also equivalent solid plate with the same weight and material.

  10. Modelling failure of welded connections to corrugated panel structures under blast loading

    Energy Technology Data Exchange (ETDEWEB)

    Louca, L.A.; Friis, J.

    2001-07-01

    This report summarises the results of a numerical analysis of shallow corrugated firewalls which was carried out to investigate uncertainties relating to the characterisation and mitigation of offshore fires and explosions in order to ascertain the limits of barrier design. In Part 1 details are given of the investigation of mild steel firewalls, the design of firewalls, the finite element model, the effect of model simplifications, and blast scenarios. Part 2 focuses on stainless steel (316) firewalls, and describes the design of blastwalls, material properties, static and blast test, and failure modelling.

  11. Impact of uncertainty in airfoil characteristics on wind turbine extreme loads

    DEFF Research Database (Denmark)

    Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

    2015-01-01

    Wind tunnel test measurements to characterize the static lift and drag coefficients of airfoils used in wind turbine blades are shown to possess large uncertainties, which leads to uncertainties in the aerodynamic loads on the rotor. In this paper a rational stochastic model is proposed to quantify...... the uncertainty in airfoil static lift and drag coefficients based on field and wind tunnel data, aero-servoelastic calculations and engineering judgment. The stochastic model is subsequently used to assess the effect of the uncertainty in airfoil static lift and drag coefficients on the prediction of extreme...

  12. MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

    Science.gov (United States)

    Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.; hide

    2010-01-01

    During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetotail increased by factors of 2 to 3.5 over intervals of 2 to 3 min. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is approx.10 times less and typical durations are approx.1 hour. The extreme tail loading observed at Mercury implies that the relative intensity of sub storms must be much larger than at Earth. The correspondence between the duration of tail field enhancements and the characteristic time for the Dungey cycle, which describes plasma circulation through Mercury's magnetosphere. suggests that such circulation determines substorm timescale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles, but no acceleration signatures were seen during the MESSENGER flyby.

  13. Lance for injecting highly-loaded coal slurries into the blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Illuminati, D.

    1991-10-29

    A lance is used to inject fuel oil into a blast furnace. This simple design permits conversion of coal water and coal tar slurries to a fine mist at very low flow rates. This design prevents the build-up of deposits which increases service life and steadies the flow rate.

  14. Quality of computerized blast load simulation for non-linear dynamic ...

    African Journals Online (AJOL)

    Simulation has been carried out using a general-purpose, commercial software system and a special-purpose, blast-specific software product to assess and compare the quality of response prediction of such computational models. Nonlinear dynamic analysis has been performed using a three-dimensional model of a ...

  15. quality of computerized blast load simulation for non-linear dynamic

    African Journals Online (AJOL)

    STRANCOM

    2005. Simulation has been carried out using a general-purpose, commercial software system and a special-purpose, blast-specific software product to assess and compare the quality of response prediction of such computational models. Nonlinear dynamic analysis has been performed using a three-dimensional model of.

  16. Ductile Tearing of Thin Aluminum Plates Under Blast Loading. Predictions with Fully Coupled Models and Biaxial Material Response Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gullerud, Arne S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haulenbeek, Kimberly K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reu, Phillip L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    The work presented in this report concerns the response and failure of thin 2024- T3 aluminum alloy circular plates to a blast load produced by the detonation of a nearby spherical charge. The plates were fully clamped around the circumference and the explosive charge was located centrally with respect to the plate. The principal objective was to conduct a numerical model validation study by comparing the results of predictions to experimental measurements of plate deformation and failure for charges with masses in the vicinity of the threshold between no tearing and tearing of the plates. Stereo digital image correlation data was acquired for all tests to measure the deflection and strains in the plates. The size of the virtual strain gage in the measurements, however, was relatively large, so the strain measurements have to be interpreted accordingly as lower bounds of the actual strains in the plate and of the severity of the strain gradients. A fully coupled interaction model between the blast and the deflection of the structure was considered. The results of the validation exercise indicated that the model predicted the deflection of the plates reasonably accurately as well as the distribution of strain on the plate. The estimation of the threshold charge based on a critical value of equivalent plastic strain measured in a bulge test, however, was not accurate. This in spite of efforts to determine the failure strain of the aluminum sheet under biaxial stress conditions. Further work is needed to be able to predict plate tearing with some degree of confidence. Given the current technology, at least one test under the actual blast conditions where the plate tears is needed to calibrate the value of equivalent plastic strain when failure occurs in the numerical model. Once that has been determined, the question of the explosive mass value at the threshold could be addressed with more confidence.

  17. Comparative Study of the Early Loading of Resorbable Blasting Media and Sandblasting with Large-grit and Acid-etching Surface Implants: A Retrospective Cohort Study

    OpenAIRE

    Kim, Sung-Beom; Kim, Young-Kyun; Kim, Su-Gwan; Oh, Ji-Su; Kim, Byung-Hoon

    2014-01-01

    Purpose: This study compares the prognosis (the survival rate and marginal bone loss) of resorbable blasting media (RBM) surface implants and sandblasting with large-grit and acid-etching (SLA) surface implants in the early loading. Methods: This study targeted 123 patients treated by implants installation from January 2008 to March 2010. The loading was initiated in the maxilla within three to four months and in the mandible within one to two months. The types of restoration were single crow...

  18. Vibration Effects of Nonclassically Damped Building-Piping Systems Subjected to Extreme Loads

    Directory of Open Access Journals (Sweden)

    YongHee Ryu

    2016-01-01

    Full Text Available Piping leakage can occur at T-joint, elbows, valves, or nozzles in nuclear power plants and nonnuclear power plants such as petrochemical plants when subjected to extreme loads and such leakage of piping systems can also lead to fire or explosion. For example, leakage of sodium, toxic gases, or nitrogen in hospitals can cause man-made hazards. The primary objective of this research is to understand the vibration effects due to classical/nonclassical damping with building-piping systems under extreme loads. The current evaluation employed finite-element analysis to calculate the effects of the responses of classically and nonclassically damped building-piping systems. Classical and nonclassical damping matrices for a coupled primary-secondary system were developed based on the Rayleigh equation. A total of 10 selected ground motions were applied to single degree of freedom (SDOF primary-SDOF secondary (2-DOF coupled systems in which the ratios of the natural frequencies between the primary and secondary systems ranged between 0.9 and 1.1. It revealed that the vibration effect of nonclassical damping was significant where the natural frequencies of the two systems were nearly tuned. For piping-material nonlinearity, the effects of nonclassical damping on the result forces of piping systems were not significantly different from those of classical damping.

  19. Nonlinear analysis for a reinforced concrete frame structure under extreme loads

    Directory of Open Access Journals (Sweden)

    Catalin BACIU

    2012-07-01

    Full Text Available Terrorist actions of the last decade obviously determine a reconsideration of the buildings safety, especially for those with special destinations (embassies, military facilities, nuclear plants etc.. Thus, the conception phase should include nowadays scenarios with exceptional actions, other than seismic loads: impact, explosion, failure of supports.It is well-known that, after earthquakes, the most situations of structural collapse are determined by the terrorist attack using explosive. Even more, it has been assessed that the main reason of loss of life is not the explosion itself, but the partial or total collapse of the exposed building.In order to secure the structural integrity, collapse analysis should be taken into account as a complex phenomenon, composed of many processes that could be studied separately or as an ensemble. These processes are: the extreme action causes, design requirements, vulnerability of the structure, starting and development of the collapse, its final effects. Study of these processes leads to additional special measures for design stage and, on the other hand, to valuable knowledge for controlled demolition of tall buildings, as part of bold urbanism projects in densely populated zones.Considering the above mentioned facts, this paper presents the results of a thorough analysis of a frame structure under explosive loads. The first part of the paper refers to the analysis of a phenomena assembly related to explosion and to the effects resulting from a terrorist attack using explosives (structural elements deterioration and failure, collapse initiation and eventual total failure. The second part of the paper presents an original approach to analyze a building structure under extreme loads, using both classical (pushover and modern (applied element method.

  20. Blast-induced neurotrauma: surrogate use, loading mechanisms, and cellular responses.

    Science.gov (United States)

    Desmoulin, Geoffrey T; Dionne, Jean-Philippe

    2009-11-01

    With the onset of improved protective equipment against fragmentation, blast-induced neurotrauma has emerged as the "signature wound" of the current conflicts in the Middle East. Current research has focused on this phenomenon; however, the exact mechanism of injury and ways to mitigate the ensuing pathophysiology remain largely unknown. The data presented and literature reviewed formed the fundamentals of a successful grant from the U.S. Office of Naval Research to Wayne State University. This work is a culmination of specialized blast physics and energy-tissue coupling knowledge, recent pilot data using a 12-m shock tube and an instrumented Hybrid III crash test dummy, modeling results from Conventional Weapons effects software, and an exhaustive Medline and government database literature review. The work supports our hypothesis of the mechanism of injury (described in detail) but sheds light on current hypotheses and how we investigate them. We expose two areas of novel mitigation development. First, there is a need to determine a physiologic and mechanism-based injury tolerance level through a combination of animal testing and biofidelic surrogate development. Once the injury mechanism is defined experimentally and an accurate physiologic threshold for brain injury is established, innovative technologies to protect personnel at risk can be appropriately assessed. Second, activated pathophysiological pathways are thought to be responsible for secondary neurodegeneration. Advanced pharmacological designs will inhibit the key cell signaling pathways. Simultaneously, evaluation of pharmacological candidates will confirm or deny current hypotheses of primary mechanisms of secondary neurodegeneration. A physiologic- or biofidelic-based blast-induced tolerance curve may redefine current acceleration-based curves that are only valid to assess tertiary blast injury. Identification of additional pharmaceutical candidates will both confirm or deny current hypotheses on

  1. Assessment of extreme design loads for modern wind turbines using the probabilistic approach

    DEFF Research Database (Denmark)

    Abdallah, Imad

    There is a large drive to reduce the cost of energy of wind energy generators. Various tracks are being considered such as enhanced O&M strategies through condition monitoring, increased manufacturing efficiency through higher production volumes and increased automation, improved resource...... capital cost (excluding foundations), today this value has dropped down to roughly 30 40% [IRENA, 2012, CleanEnergyPipeline, 2014]. Wind turbine manufacturers and researchers have indeed delivered on the promise of cost reduction, but the question remains: can we do more? The research in this thesis aimed...... analytical methods for fusing output from multi-fidelity aero-servo-elastic simulators with application to extreme loads on a wind turbine. Analysts and designers increasingly use multiple commercial and research-based aero-servo-elastic simulators such as FLEX, FAST, BLADED, HAWC2, Cp-Lambda, etc...

  2. Survivability Mode and Extreme Loads on the Mooring Lines of the Wave Dragon Wave Energy Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Kofoed, Jens Peter

    This report is a product of the cooperation agreement between Wave Dragon and Aalborg University regarding phase 2 of the development of the Wave Dragon Wave Energy Converter. The research is carried out by testing the 1:51.8 scale model of the Wave Dragon, aiming at the assessment...... of the survivability of the device in extreme waves and evaluation of the design loads for the mooring component. The testing has been carried out in October 2010 by PhD student Stefano Parmeggiani and Master students Giovanna Bevilacqua and Giacomo Girardi Ferruzza at the Hydraulic and Coastal Laboratories...... of the department of Civil Engineering at Aalborg University. The outcome of the research will be used as input for future research work aimed at the design of the mooring system and the certification of the structural design for the full scale Wave Dragon demonstrator....

  3. Dynamic Response of Cable-Supported Façades Subjected to High-Level Air Blast Loads: Numerical Simulations and Mitigation Techniques

    Directory of Open Access Journals (Sweden)

    Claudio Amadio

    2012-01-01

    Full Text Available A glazing façade subjected to blast loads has a structural behaviour that strongly differs from the typical response of a glazing system subjected to ordinary loads. Consequently, sophisticated modelling techniques are required to identify correctly its criticalities. The paper investigates the behaviour of a cable-supported façade subjected to high-level blast loading. Nonlinear dynamic analyses are performed in ABAQUS/Explicit using a sophisticated FE-model (M01, calibrated to dynamic experimental and numerical results. The structural effects of the total design blast impulse, as well as only its positive phase, are analyzed. At the same time, the possible cracking of glass panels is taken into account, since this phenomenon could modify the response of the entire façade. Finally, deep investigations are dedicated to the bearing cables, since subjecting them to elevated axial forces and their collapse could compromise the integrity of the cladding wall. Based on results of previous studies, frictional devices differently applied at their ends are presented to improve the response of the façade under the impact of a high-level explosion. Structural effects of various solutions are highlighted through dynamic simulations. Single vertical devices, if appropriately calibrated, allow reducing significantly the axial forces in cables, and lightly the tensile stresses in glass panes.

  4. Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is nonexistent but necessary to protect the heart and lungs. In tests against ballistic projectiles, protective apparel is placed over ballistic clay and the projectiles are fired into the armor/clay target. The clay represents the human torso and its behind-armor, permanent deflection is the principal metric used to assess armor protection. Although this approach provides relative merit assessment of protection, it does not examine the behind-armor blunt trauma to crucial torso organs. We propose a modeling and simulation (M&S) capability for wound injury scenarios to the head, neck, and torso of the warfighter. We will use this toolset to investigate the consequences of, and mitigation against, blast exposure, blunt force impact, and ballistic projectile penetration leading to damage of critical organs comprising the central nervous, cardiovascular, and respiratory systems. We will leverage Sandia codes and our M&S expertise on traumatic brain injury to develop virtual anatomical models of the head, neck, and torso and the simulation methodology to capture the physics of wound mechanics. Specifically, we will investigate virtual wound injuries to the head, neck, and torso without and with protective armor to demonstrate the advantages of performing injury simulations for the development of body armor. The proposed toolset constitutes a significant advance over current methods by providing a virtual simulation capability to investigate wound injury and optimize armor design without the need for extensive field testing.

  5. Full Scale Test SSP 34m blade, edgewise loading LTT. Extreme load and PoC_InvE Data report

    DEFF Research Database (Denmark)

    Nielsen, Magda; Roczek-Sieradzan, Agnieszka; Jensen, Find Mølholt

    in edgewise direction (LTT). The blade has been submitted to thorough examination by means of strain gauges, displacement transducers and a 3D optical measuring system. This data report presents results obtained during full scale testing of the blade up to 80% Risø load, where 80% Risø load corresponds to 100......% certification load. These pulls at 80% Risø load were repeated and the results from these pulls were compared. The blade was reinforced according to a Risø DTU invention, where the trailing edge panels are coupled. The coupling is implemented to prevent the out of plane deformations and to reduce peeling...

  6. Ultramarathon is an outstanding model for the study of adaptive responses to extreme load and stress

    Directory of Open Access Journals (Sweden)

    Millet Grégoire P

    2012-07-01

    Full Text Available Abstract Ultramarathons comprise any sporting event involving running longer than the traditional marathon length of 42.195 km (26.2 miles. Studies on ultramarathon participants can investigate the acute consequences of ultra-endurance exercise on inflammation and cardiovascular or renal consequences, as well as endocrine/energetic aspects, and examine the tissue recovery process over several days of extreme physical load. In a study published in BMC Medicine, Schütz et al. followed 44 ultramarathon runners over 4,487 km from South Italy to North Cape, Norway (the Trans Europe Foot Race 2009 and recorded daily sets of data from magnetic resonance imaging, psychometric, body composition and biological measurements. The findings will allow us to better understand the timecourse of degeneration/regeneration of some lower leg tissues such as knee joint cartilage, to differentiate running-induced from age-induced pathologies (for example, retropatelar arthritis and finally to assess the interindividual susceptibility to injuries. Moreover, it will also provide new information about the complex interplay between cerebral adaptations/alterations and hormonal influences resulting from endurance exercise and provide data on the dose-response relationship between exercise and brain structure/function. Overall, this study represents a unique attempt to investigate the limits of the adaptive response of human bodies. Please see related article: http://www.biomedcentral.com/1741-7015/10/78

  7. Numerical simulation of muzzle blast

    NARCIS (Netherlands)

    Tyler-Street, M.

    2014-01-01

    Structural design methods for naval ships include environmental, operational and military load cases. One of the operational loads acting on a typical naval vessel is the muzzle blast from a gun. Simulating the muzzle blast load acting on a ship structure with CFD and ALE methods leads to large

  8. Characterization and Modeling of Thoraco-Abdominal Response to Blast Waves. Volume 4. Biomechanical Model of Thorax Response to Blast Loading

    Science.gov (United States)

    1985-05-01

    Foundation of Albuquerque, New Mexico in the past 30 years [10, 15, 16, 17]. The study of blast effect on biological bodies has also been advanced by...Thoraco- Abdominal System’s Response to Underwater Blast,. Lovelace Foundation, Albuquerque, Now Mexico , Report LP-55 (1976). 18. Jbnsson, A...134:Y aoo’:.rs I:. U 135: IR IT 201:D026 I 36:P 1?. 202:2028.U 1l?: READ 283:021. 130: PIB . 294:D21.U 139:y 205:21 14,: WRIT 296:P1. 141:P-118. 207:PlU

  9. Multilevel Vehicle Design: Fuel Economy, Mobility and Safety Considerations, Part B. Ground Vehicle Weight and Occupant Safety Under Blast Loading

    Science.gov (United States)

    2010-05-11

    Major skin laceration or avulsion with ង% blood loss  Nerve contusions or lacerations  Vertebral dislocation without fracture  Herniated disc ...Charge Mass Outputs: Upper Neck Axial Force Lower Lumbar Axial Force Lower Tibia Axial Force Blast Pulse of Vehicle Inputs: Blast Pulse (magnitude...Simulation Uncertainty in Occupant Body Forces Lower Leg Compression Lumbar Spine Compression Upper Neck Compression Optimization to Minimize

  10. Blast Loading and Response of Underground Concrete-Arch Protective Structures

    Science.gov (United States)

    1959-06-05

    2.4 Concrete Design Mix per Cubic Yard ------------------------------- 25 2.5 Concrete Strengh Characteristics --------------------------------- 29...voltage for each channel was supplied designed and fabricated by NCEL. They consisted of by three CEC Type 2-I05A oscillator- power bupplies an 8-inch-long...10f.A power system similar to the BRL gage was used to spring su.)plies and t) drive the three power supplies from a load the wire. Figure C.3 shows a

  11. 29 CFR 1926.912 - Underwater blasting.

    Science.gov (United States)

    2010-07-01

    ... nonsparking metal loading tube when tube is necessary. (d) No blast shall be fired while any vessel under way... his approval. (b) Loading tubes and casings of dissimilar metals shall not be used because of possible... within 1,500 feet shall be notified before a blast is fired. (e) No blast shall be fired while any...

  12. Extremely low catalyst loading for electroless deposition on a non-conductive surface by a treatment for reduced graphene oxide.

    Science.gov (United States)

    Zhan, Jing; Tan, Desmond C L; Prakitritanon, Swaek; Lin, Ming; Sato, Hirotaka

    2017-08-15

    Enhancement of electroless deposition using reduced-graphene-oxide (rGO) coating for a conductive surface on the non-conductive substrate is proposed and demonstrated. We confirmed that the rGO treatment enhanced the Pd catalytic activity and achieved a sufficient rate in electroless deposition with extremely low Pd loading (3.94 × 10-2 μg cm-2).

  13. Evaluation of observed blast loading effects on NIF x-ray diagnostic collimators.

    Science.gov (United States)

    Masters, N D; Fisher, A; Kalantar, D; Prasad, R; Stölken, J S; Wlodarczyk, C

    2014-11-01

    We present the "debris wind" models used to estimate the impulsive load to which x-ray diagnostics and other structures are subject during National Ignition Facility experiments. These models are used as part of the engineering design process. Isotropic models, based on simulations or simplified "expanding shell" models, are augmented by debris wind multipliers to account for directional anisotropy. We present improvements to these multipliers based on measurements of the permanent deflections of diagnostic components: 4× for the polar direction and 2× within the equatorial plane-the latter relaxing the previous heuristic debris wind multiplier.

  14. Blast Valve Design and Related Studies : A Review

    OpenAIRE

    Sharma, P.K.; Patel, B. P.; Harbans Lal

    2016-01-01

    The protective structures required for performing critical operations are vulnerable to the blast and shock loads of advanced weapons. A blast valve is an important component of such structures for ventilation during normal conditions and for protection from blast/ shock during explosion. In this paper, various aspects of blast valve design and related studies are briefly reviewed. The concept and effects of blast wave, blast impact, numerical modelling and deformation of circular plate (one ...

  15. Ultimate design load analysis of planetary gearbox bearings under extreme events

    DEFF Research Database (Denmark)

    Gallego Calderon, Juan Felipe; Natarajan, Anand; Cutululis, Nicolaos Antonio

    2017-01-01

    This paper investigates the impact of extreme events on the planet bearings of a 5 MW gearbox. The system is simulated using an aeroelastic tool, where the turbine structure is modeled, and MATLAB/Simulink, where the drivetrain (gearbox and generator) are modeled using a lumped-parameter approach...

  16. Hollow-core FRP-concrete-steel bridge columns under extreme loading.

    Science.gov (United States)

    2015-04-01

    This report presents the behavior of hollow-core fiber reinforced polymer concrete - steel columns (HC-FCS) under : combined axial-flexural as well as vehicle collision loads. The HC-FCS column consists of a concrete wall sandwiched between an ou...

  17. Dynamic behaviour of TM380 mild steel and Ti6Al4V alloy subjected to blast loading

    CSIR Research Space (South Africa)

    Shoke, Lerato

    2016-10-01

    Full Text Available distance of 72 mm. A blast pendulum recorded the imparted impulse and a deflection gauge measured the dynamic mid-point deflection of the plate. Samples were cut from the test plates, mounted and polished for metallographic and failure analysis using...

  18. On the mechanical modeling of the extreme softening/stiffening response of axially loaded tensegrity prisms

    Science.gov (United States)

    Fraternali, Fernando; Carpentieri, Gerardo; Amendola, Ada

    2015-01-01

    We study the geometrically nonlinear behavior of uniformly compressed tensegrity prisms through fully elastic and rigid-elastic models. The given models predict a variety of mechanical behaviors in the regime of large displacements, including an extreme stiffening-type response, already known in the literature, and a newly discovered, extreme softening behavior. The latter may lead to a snap buckling event producing an axial collapse of the structure. The switching from one mechanical regime to another depends on the aspect ratio of the structure, the magnitude of the applied prestress, and the material properties of the constituent elements. We discuss potential mechanical and acoustic applications of such behaviors, which are related to the design and manufacture of tensegrity lattices and innovative metamaterials.

  19. Extreme Value Predictions using Monte Carlo Simulations with Artificially Increased Load Spectrum

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2011-01-01

    an approximation to the mean outcrossing rate. Better accuracy can be obtained by Monte Carlo simulations, but the necessary length of the time domain simulations for very low out-crossing rates might be prohibitively long. In such cases the property mentioned above for the FORM reliability index might be assumed...... to be valid in the Monte Carlo simulations, making it possible to increase the out-crossing rates and thus reduce the necessary length of the time domain simulations by applying a larger load spectrum than relevant from a design point of view. The mean out-crossing rate thus obtained can then afterwards...... be found using the First Order Reliability Method (FORM). The FORM analysis also shows that the reliability index is strictly inversely proportional to the square root of the magnitude of the load spectrum, irrespectively of the non-linearity in the system. However, the FORM analysis only gives...

  20. Crystal Thermoelasticity at Extreme Loading Rates and Pressures: Analysis of Higher-Order Energy Potentials

    Science.gov (United States)

    2015-07-01

    effective elastic shear to bulk modulus. 15. SUBJECT TERMS dynamic loading, shock compression, constitutive modeling, nonlinear elasticity, equation of...where ‘‘plastic’’ refers here to any thermodynam- ically irreversible mechanism such as dislocation glide, de - formation twinning, fracture, void...σ sym- metric Cauchy stress, and U internal energy per reference volume. Letting ξ denote an internal state variable linked to evolution of

  1. Short-Term Electricity-Load Forecasting Using a TSK-Based Extreme Learning Machine with Knowledge Representation

    Directory of Open Access Journals (Sweden)

    Chan-Uk Yeom

    2017-10-01

    Full Text Available This paper discusses short-term electricity-load forecasting using an extreme learning machine (ELM with automatic knowledge representation from a given input-output data set. For this purpose, we use a Takagi-Sugeno-Kang (TSK-based ELM to develop a systematic approach to generating if-then rules, while the conventional ELM operates without knowledge information. The TSK-ELM design includes a two-phase development. First, we generate an initial random-partition matrix and estimate cluster centers for random clustering. The obtained cluster centers are used to determine the premise parameters of fuzzy if-then rules. Next, the linear weights of the TSK fuzzy type are estimated using the least squares estimate (LSE method. These linear weights are used as the consequent parameters in the TSK-ELM design. The experiments were performed on short-term electricity-load data for forecasting. The electricity-load data were used to forecast hourly day-ahead loads given temperature forecasts; holiday information; and historical loads from the New England ISO. In order to quantify the performance of the forecaster, we use metrics and statistical characteristics such as root mean squared error (RMSE as well as mean absolute error (MAE, mean absolute percent error (MAPE, and R-squared, respectively. The experimental results revealed that the proposed method showed good performance when compared with a conventional ELM with four activation functions such sigmoid, sine, radial basis function, and rectified linear unit (ReLU. It possessed superior prediction performance and knowledge information and a small number of rules.

  2. Angiographic assessment of atherosclerotic load at the lower extremity in patients with diabetic foot and charcot neuro-arthropathy.

    Science.gov (United States)

    Çildağ, Mehmet B; Ertuğrul, Bülent M; Köseoğlu, Ömer Fk; Çildağ, Songül; Armstrong, David G

    2017-10-19

    The aim of this study was to investigate atherosclerotic load at the lower extremity in patients with diabetic foot and charcot neuro-arthropathy and compare them with patients with diabetic foot without charcot neuro-arthropathy. This retrospective study consists of 78 patients with diabetic foot who had lower extremity angiography with antegrade approach. All patients were classified into two groups; neuro ischemic wounds with charcot neuro-arthropathy (30/78) and without charcot neuro-arthropathy (48/78).Atherosclerotic load at the side of diabetic foot was determined by using the Bollinger angiogram scoring method. Comparison of atherosclerotic load between the two groups was performed. The mean of total and infrapopliteal level angiogram scoring of all patients was 33.3 (std±17.2) and 29.3 (std±15.6), respectively. The mean of total and infrapopliteal level angiogram scoring of neuroischemic wounds with charcot neuro-arthropathy group was 18.1 (std±11.6) and 15.7 (std±10.4), respectively. The mean of total and infrapopliteal level angiogram scoring of neuroischemic wounds without charcot neuro-arthropathy group was 42.8 (std±12.7) and 37.7 (std±12.0), respectively. There was a statistically significant difference between the two groups of mean total and infrapopliteal angiogram scoring (p charcot neuro-arthropathy is significantly less than in patients with neuroischemic diabetic foot wounds without chronic charcot neuro-arthropathy. Copyright © 2017. Published by Elsevier Taiwan LLC.

  3. Three-Dimensional Lower Extremity Joint Loading in a Carved Ski and Snowboard Turn: A Pilot Study

    Science.gov (United States)

    Müller, Erich

    2014-01-01

    A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER). Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase. PMID:25317202

  4. Three-Dimensional Lower Extremity Joint Loading in a Carved Ski and Snowboard Turn: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Miriam Klous

    2014-01-01

    Full Text Available A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER. Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase.

  5. Effect of Smart Rotor Control Using a Deformable Trailing Edge Flap on Load Reduction under Normal and Extreme Turbulence

    Directory of Open Access Journals (Sweden)

    Jian Zhong Xu

    2012-09-01

    Full Text Available This paper presents a newly developed aero-servo-elastic platform for implementing smart rotor control and shows its effectiveness with aerodynamic loads on large-scale offshore wind turbines. The platform was built by improving the FAST/Aerodyn codes with the integration of an external deformable trailing edge flap controller in the Matlab/Simulink software. Smart rotor control was applied to an Upwind/NREL 5 MW reference wind turbine under various operating wind conditions in accordance with the IEC Normal Turbulence Model (NTM and Extreme Turbulence Model (ETM. Results showed that, irrespective of whether the NTM or ETM case was considered, aerodynamic load in terms of blade flapwise root moment and tip deflection were effectively reduced. Furthermore, the smart rotor control also positively affected generator power, pitch system and tower load. These results laying a foundation for a future migration of the “smart rotor control” concept into the design of large-scale offshore wind turbines.

  6. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period

    Directory of Open Access Journals (Sweden)

    Burke DT

    2013-10-01

    Full Text Available David T Burke,1 David Tran,1 Di Cui,1 Daniel P Burke,2 Samir Al-Adawi,3 Atsu SS Dorvlo41Emory University Medical School, Atlanta, GA, USA; 2Georgia College and State University, GA, USA; 3Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; 4Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat, OmanAbstract: In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.Keywords: Anatoly Gravitational System, weight training, musculoskeletal system

  7. Extremely efficient crystallization of HKUST-1 and Keggin-loaded related phases through the epoxide route.

    Science.gov (United States)

    Oestreicher, Víctor; Jobbágy, Matías

    2017-03-25

    Highly crystalline HKUST-1 and COK-16-like phases were obtained based on a mild in situ alkalinization one-pot epoxide driven method. A slurry composed of finely ground trimesic acid, H3BTC, dispersed in a CuCl2 aqueous solution quantitatively developed well crystallized HKUST-1 after the addition of propylene oxide. The use of solid H3BTC ensures a low concentration of free linker, favoring crystalline growth over the precipitation of amorphous or metastable impurities. An extreme space-time yield of 2.1 × 10(5) kg m(-3) day(-1) was reached, with no linker excess and minimum use of solvent. The method was equally efficient in the achievement of pure NENU/COK-16 phases, containing [PW12O40](3-), [PMo12O40](3-) and [SiMo12O40](4-) polyoxometalates.

  8. ANALYSIS OF DESIGN RANGE FOR A STROKING SEAT ON A STROKING FLOOR TO MITIGATE BLAST LOADING EFFECTS

    Science.gov (United States)

    2017-05-16

    computational solver called MADYMO (Mathematical Dynamics Model) [8-9]. The model, as shown in Figure 2, consists of Vehicle hull with stroking floor with a...size, and theater conditions like soil type, depth of burial etc. The relative dynamic performance of the seat and floor systems depend on the vehicle ...Order Modeling for Rapid Simulations of Blast and Rollover Events of a Ground Vehicle and its Occupants Using Rigid Body Dynamic Models”, DTIC

  9. Effect of Enhanced Air Temperature (extreme heat, and Load of Non-Linear Against the Use of Electric Power

    Directory of Open Access Journals (Sweden)

    I Ketut Wijaya

    2015-12-01

    Full Text Available Usage Electric power is very easy to do, because the infrastructure for connecting  already available and widely sold. Consumption electric power is not accompanied by the ability to recognize electric power. The average increase of electricity power in Bali in extreme weather reaches 10% in years 2014, so that Bali suffered power shortages and PLN as the manager of electric power to perform scheduling on of electric power usage. Scheduling is done because many people use electric power as the load  of fan and Air Conditioner exceeding the previous time. Load of fan, air conditioning, and computers including non-linear loads which can add heat on the conductor of electricity. Non-linear load and hot weather can lead to heat on conductor so  insulation damaged  and cause electrical short circuit. Data of electric power obtained through questionnaires, surveys, measurement and retrieve data from various parties. Fires that occurred in 2014, namely 109 events, 44 is  event caused by an electric short circuit (approximately 40%. Decrease power factors can cause losses of electricity and hot. Heat can cause and adds heat on the  conductor electric. The analysis showed  understanding electric power of the average  is 27,700 with value between 20 to 40. So an understanding of the electrical power away from the understand so that many errors because of the act own. Installation tool ELCB very necessary but very necessary provide counseling   of electricity to the community.

  10. [Process strategy for ethanol production from lignocellulose feedstock under extremely low water usage and high solids loading conditions].

    Science.gov (United States)

    Zhang, Jian; Chu, Deqiang; Yu, Zhanchun; Zhang, Xiaoxi; Deng, Hongbo; Wang, Xiusheng; Zhu, Zhinan; Zhang, Huaiqing; Dai, Gance; Bao, Jie

    2010-07-01

    The massive water and steam are consumed in the production of cellulose ethanol, which correspondingly results in the significant increase of energy cost, waster water discharge and production cost as well. In this study, the process strategy under extremely low water usage and high solids loading of corn stover was investigated experimentally and computationally. The novel pretreatment technology with zero waste water discharge was developed; in which a unique biodetoxification method using a kerosene fungus strain Amorphotheca resinae ZN1 to degrade the lignocellulose derived inhibitors was applied. With high solids loading of pretreated corn stover, high ethanol titer was achieved in the simultaneous saccharification and fermentation process, and the scale-up principles were studied. Furthermore, the flowsheet simulation of the whole process was carried out with the Aspen plus based physical database, and the integrated process developed was tested in the biorefinery mini-plant. Finally, the core technologies were applied in the cellulose ethanol demonstration plant, which paved a way for the establishment of an energy saving and environment friendly technology of lignocellulose biotransformation with industry application potential.

  11. The effect of prosthetic foot push-off on mechanical loading associated with knee osteoarthritis in lower extremity amputees.

    Science.gov (United States)

    Morgenroth, David C; Segal, Ava D; Zelik, Karl E; Czerniecki, Joseph M; Klute, Glenn K; Adamczyk, Peter G; Orendurff, Michael S; Hahn, Michael E; Collins, Steven H; Kuo, Art D

    2011-10-01

    Lower extremity amputation not only limits mobility, but also increases the risk of knee osteoarthritis of the intact limb. Dynamic walking models of non-amputees suggest that pushing-off from the trailing limb can reduce collision forces on the leading limb. These collision forces may determine the peak knee external adduction moment (EAM), which has been linked to the development of knee OA in the general population. We therefore hypothesized that greater prosthetic push-off would lead to reduced loading and knee EAM of the intact limb in unilateral transtibial amputees. Seven unilateral transtibial amputees were studied during gait under three prosthetic foot conditions that were intended to vary push-off. Prosthetic foot-ankle push-off work, intact limb knee EAM and ground reaction impulses for both limbs during step-to-step transition were measured. Overall, trailing limb prosthetic push-off work was negatively correlated with leading intact limb 1st peak knee EAM (slope=-.72±.22; p=.011). Prosthetic push-off work and 1st peak intact knee EAM varied significantly with foot type. The prosthetic foot condition with the least push-off demonstrated the largest knee EAM, which was reduced by 26% with the prosthetic foot producing the most push-off. Trailing prosthetic limb push-off impulse was negatively correlated with leading intact limb loading impulse (slope=-.34±.14; p=.001), which may help explain how prosthetic limb push-off can affect intact limb loading. Prosthetic feet that perform more prosthetic push-off appear to be associated with a reduction in 1st peak intact knee EAM, and their use could potentially reduce the risk and burden of knee osteoarthritis in this population. Published by Elsevier B.V.

  12. Comparative Study of the Early Loading of Resorbable Blasting Media and Sandblasting with Large-grit and Acid-etching Surface Implants: A Retrospective Cohort Study

    Science.gov (United States)

    Kim, Sung-Beom; Kim, Young-Kyun; Kim, Su-Gwan; Oh, Ji-Su; Kim, Byung-Hoon

    2014-01-01

    Purpose: This study compares the prognosis (the survival rate and marginal bone loss) of resorbable blasting media (RBM) surface implants and sandblasting with large-grit and acid-etching (SLA) surface implants in the early loading. Methods: This study targeted 123 patients treated by implants installation from January 2008 to March 2010. The loading was initiated in the maxilla within three to four months and in the mandible within one to two months. The types of restoration were single crown and fixed partial prosthesis. Those functioned over one year. The implants were classified by the surface of implants as Group 1: RBM surface (GS III; OSSTEM, Busan, Korea) and, Group 2: SLA surface (Superline; Dentium, Seoul, Korea). The groups were categorized by maxilla and mandible and compared by survival rate, marginal bone loss through clinical records evaluation, and radiographic measurements. Results: The marginal bone loss in the maxilla was 0.14±0.34 mm (Group 1) and 0.30±0.37 mm (Group 2), a statistically significant difference (P 0.05). There was no significant difference of marginal bone loss between maxilla and mandible by groups. During observation there was no implant failure, a survival rate of 100%. Conclusion: Both surfaces showed an excellent survival rate, and the marginal bone loss was not substantial. PMID:27489842

  13. Blast mitigation experimental and numerical studies

    CERN Document Server

    2013-01-01

    Presents experimental methods of material and structural response to dynamic blast loads Includes computational analysis of material and structural response to dynamic blast loads Offers mitigation measures for structures in various environments Relates lab experiments to larger field tests Features more than 150 illustrations

  14. A Novel Hybrid Model Based on Extreme Learning Machine, k-Nearest Neighbor Regression and Wavelet Denoising Applied to Short-Term Electric Load Forecasting

    Directory of Open Access Journals (Sweden)

    Weide Li

    2017-05-01

    Full Text Available Electric load forecasting plays an important role in electricity markets and power systems. Because electric load time series are complicated and nonlinear, it is very difficult to achieve a satisfactory forecasting accuracy. In this paper, a hybrid model, Wavelet Denoising-Extreme Learning Machine optimized by k-Nearest Neighbor Regression (EWKM, which combines k-Nearest Neighbor (KNN and Extreme Learning Machine (ELM based on a wavelet denoising technique is proposed for short-term load forecasting. The proposed hybrid model decomposes the time series into a low frequency-associated main signal and some detailed signals associated with high frequencies at first, then uses KNN to determine the independent and dependent variables from the low-frequency signal. Finally, the ELM is used to get the non-linear relationship between these variables to get the final prediction result for the electric load. Compared with three other models, Extreme Learning Machine optimized by k-Nearest Neighbor Regression (EKM, Wavelet Denoising-Extreme Learning Machine (WKM and Wavelet Denoising-Back Propagation Neural Network optimized by k-Nearest Neighbor Regression (WNNM, the model proposed in this paper can improve the accuracy efficiently. New South Wales is the economic powerhouse of Australia, so we use the proposed model to predict electric demand for that region. The accurate prediction has a significant meaning.

  15. High loads and their influence on thermal insulation of insulating materials; Extreme Beanspruchungen und deren Auswirkungen auf die Waermedaemmwirkung von Daemmstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, R.

    2001-12-14

    Changing climatical conditions like strong rain, high temperatures or vibration loads, can reduce sensitively the efficiency of heat insulating materials involving an expensive sanitation. [German] Durch extrem veraenderte klimatische Randbedingungen im Anwendungsfall, wie z.B. Auftreten von Wasser, ueberhoehte Temperatur oder Schwingbeanspruchungen, ist mit einer Verminderung der Waermedaemmwirkung von Daemmstoffprodukten zu rechnen. (orig.)

  16. Structural and functional responses of extremity veins to long-term gravitational loading or unloading—lessons from animal systems

    Science.gov (United States)

    Monos, Emil; Raffai, Gábor; Dörnyei, Gabriella; Nádasy, György L.; Fehér, Erzsébet

    2007-02-01

    Long, transparent tubular tilt-cages were developed to maintain experimental rats either in 45∘ head-up (orthostasis model), or in 45∘ head-down body position (antiorthostasis model) for several weeks. In order to study the functional and structural changes in extremity blood vessels, also novel pressure angiograph systems, as well as special quantitative electron microscopic methods were applied. It was found that several adaptive mechanisms are activated in the lower limb superficial veins and microvessels of muscles when an organism is exposed to long-term (1-2 weeks) orthostatic-type gravitational load including a reversible amplification of the pressure-dependent myogenic response, tuning of the myogenic tone by Ca++- and voltage-sensitive K+ channels in humans, augmentation of the intramural sympathetic innervation involving an increased nerve terminal density and synaptic vesicle count with functional remodeling, reorganization of vascular network properties (microvascular rarefaction in muscles, decreased branching angles in superficial veins), and responses of an endothelin and platelet-derived growth factor (PDGF) containing vesicle system in the endothelium. On the other hand, when applying long-term head-down tilting, the effects are dichotomous, e.g. it suppresses significantly the pressure-induced myogenic response, however does not diminish the adventitial sympathetic innervation density.

  17. A Parametric Approach to Shape Field-Relevant Blast Wave Profiles in Compressed-Gas-Driven Shock Tube

    Science.gov (United States)

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1–3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68–1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is

  18. A parametric approach to shape field-relevant blast wave profiles in compressed-gas-driven shock tube.

    Science.gov (United States)

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1-3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68-1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is compared

  19. Practical evaluation of the MiL-Lx lower leg when subjected to simulated vehicle under belly blast load conditions

    CSIR Research Space (South Africa)

    Pandelani, T

    2010-09-01

    Full Text Available show that the Mil-Lx lower leg appears to be robust and is less sensitive to loading method, temperature, Personal Protective Equipment (PPE) and position changes than other lower limb surrogates tested previously....

  20. Effects of Cylindrical Charge Geometry and Secondary Combustion Reactions on the Internal Blast Loading of Reinforced Concrete Structures

    Energy Technology Data Exchange (ETDEWEB)

    Price, Matthew A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2005-05-01

    An understanding of the detonation phenomenon and airblast behavior for cylindrical high-explosive charges is essential in developing predictive capabilities for tests and scenarios involving these charge geometries. Internal tests on reinforced concrete structures allowed for the analysis of cylindrical charges and the effect of secondary reactions occurring in confined structures. The pressure profiles that occur close to a cylindrical explosive charge are strongly dependent on the length-to-diameter ratio (L/D) of the charge. This study presents a comparison of finite-element code models (i.e., AUTODYN) to empirical methods for predicting airblast behavior from cylindrical charges. Current finite element analysis (FEA) and blast prediction codes fail to account for the effects of secondary reactions (fireballs) that occur with underoxidized explosives. Theoretical models were developed for TNT and validated against literature. These models were then applied to PBX 9501 for predictions of the spherical fireball diameter and time duration. The following relationships for PBX 9501 were derived from this analysis (units of ft, lb, s). Comparison of centrally located equivalent weight charges using cylindrical and spherical geometries showed that the average impulse on the interior of the structure is ~3%–5% higher for the spherical charge. Circular regions of high impulse that occur along the axial direction of the cylindrical charge must be considered when analyzing structural response.

  1. Prognostic factors for specific lower extremity and spinal musculoskeletal injuries identified through medical screening and training load monitoring in professional football (soccer): a systematic review.

    Science.gov (United States)

    Hughes, Tom; Sergeant, Jamie C; Parkes, Matthew J; Callaghan, Michael J

    2017-01-01

    Medical screening and load monitoring procedures are commonly used in professional football to assess factors perceived to be associated with injury. To identify prognostic factors (PFs) and models for lower extremity and spinal musculoskeletal injuries in professional/elite football players from medical screening and training load monitoring processes. The MEDLINE, AMED, EMBASE, CINAHL Plus, SPORTDiscus and PubMed electronic bibliographic databases were searched (from inception to January 2017). Prospective and retrospective cohort studies of lower extremity and spinal musculoskeletal injury incidence in professional/elite football players aged between 16 and 40 years were included. The Quality in Prognostic Studies appraisal tool and the modified Grading of Recommendations Assessment, Development and Evaluation synthesis approach was used to assess the quality of the evidence. Fourteen studies were included. 16 specific lower extremity injury outcomes were identified. No spinal injury outcomes were identified. Meta-analysis was not possible due to heterogeneity and study quality. All evidence related to PFs and specific lower extremity injury outcomes was of very low to low quality. On the few occasions where multiple studies could be used to compare PFs and outcomes, only two factors demonstrated consensus. A history of previous hamstring injuries (HSI) and increasing age may be prognostic for future HSI in male players. The assumed ability of medical screening tests to predict specific musculoskeletal injuries is not supported by the current evidence. Screening procedures should currently be considered as benchmarks of function or performance only. The prognostic value of load monitoring modalities is unknown.

  2. Comparison of Building Loads Analysis and System Thermodynamics (BLAST) Computer Program Simulations and Measured Energy Use for Army Buildings.

    Science.gov (United States)

    1980-05-01

    RGRAM MULATTONS AND MESRDEN RGV USE FO~ ARMY ING OG.-WEPORT NUM1SER * HeronS . CONTRACT OR GRANT NUMBER(*) i,_q Unclassified r C64TRUCTI~IS. ONECOSTRU...was wrong, since the clinic has a minimum baseline electrical load; i.e., vending machines, drinking fountains , refrigerators, emergency and security

  3. Effects of two different degrees of lateral-wedge insoles on unilateral lower extremity load-bearing line in patients with medial knee osteoarthritis.

    Science.gov (United States)

    Yılmaz, Bilge; Kesikburun, Serdar; Köroğlu, Ozlem; Yaşar, Evren; Göktepe, Ahmet Salim; Yazıcıoğlu, Kamil

    2016-08-01

    The aim of this study is to assess the effect of 5 and 10° lateral-wedge insoles on unilateral lower extremity load carrying line in patients with medial knee osteoarthritis using the L.A.S.A.R. posture alignment system. Twenty subjects (10 females and 10 males, mean age 67.7 ± 5.4 years (range: 58-78) with bilateral medial knee osteoarthritis were included in the study. The laser line projected on the person by the L.A.S.A.R. posture alignment system showed joint load carrying line. The location of the joint load carrying line in static standing with one foot on the force plate was assessed with barefoot, and 5° and 10° lateral-wedge insoles. Displacement of the load carrying line was measured using a ruler placed tangentially to the patella at the level of joint line. The load carrying lines measured with 5° and 10° lateral-wedge insoles were significantly laterally located compared to that without wearing insole (p lateral-wedge insole caused a significant more lateral shifting of the load carrying line than 5° lateral-wedge insole (p line to the lateral. Lateral wedged insoles are biomechanically effective and reduce loading of the medial compartment in patients with medial knee osteoarthritis. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  4. Research on Effects of Blast Casting Vibration and Vibration Absorption of Presplitting Blasting in Open Cast Mine

    Directory of Open Access Journals (Sweden)

    Li Ma

    2016-01-01

    Full Text Available The impact energy produced by blast casting is able to break and cast rocks, yet the strong vibration effects caused at the same time would threaten the safety of mines. Based on the theory of Janbu’s Limit Equilibrium Method (LEM, pseudo-static method has been incorporated to analyze the influence of dynamic loads of blasting on slope stability. The horizontal loads produced by blast vibrations cause an increase in sliding forces, and this leads to a lower slope stability coefficient. When the tensile stresses of the two adjacent blast holes are greater than the tensile strength of rock mass, the radical oriented cracks are formed, which is the precondition for the formation of presplit face. Thus, the formula for calculating the blast hole spacing of presplit blasting can be obtained. Based on the analysis of the principles of vibration tester and vibration pick-up in detecting blast vibrations, a detection scheme of blast vibration is worked out by taking the blast area with precrack rear and non-precrack side of the detection object. The detection and research results of blast vibration show that presplit blasting can reduce the attenuation coefficient of stress wave by half, and the vibration absorption ratio could reach 50.2%; the impact of dynamic loads on the end-wall slope stability coefficient is 1.98%, which proves that presplit blasting plays an important role in shock absorption of blast casting.

  5. The design of a modified lower limb impactor to assess lower limb injury at typical blast loading rates

    CSIR Research Space (South Africa)

    Pandelani, T

    2014-01-01

    Full Text Available tibia peak force averaged 5154 N and ranged from 5013 N to 5161 N. The MiL-Lx leg’s biomechanical response demonstrated high repeatability with a standard deviation of 137 N for the tibia peak load. Discussion Figure 6 shows the comparison... towards understanding the mechanism of injury. Conclusions The experimental apparatus presented here allows for biomechanical lower limbs surrogates to be tested at various postures, and offers an independent test-bed for assessing the bio...

  6. Full scale test SSP 34m blade, edgewise loading LTT. Extreme load and PoC{sub I}nvE Data report

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Magda; Roczek-Sieradzan, A.; Jensen, Find M. (and others)

    2010-09-15

    This report is the second report covering the research and demonstration project 'Experimental blade research: Structural mechanisms in current and future large blades under combined loading', supported by the EUDP program. A 34m wind turbine blade from SSP-Technology A/S has been tested in edgewise direction (LTT). The blade has been submitted to thorough examination by means of strain gauges, displacement transducers and a 3D optical measuring system. This data report presents results obtained during full scale testing of the blade up to 80% Risoe load, where 80% Risoe load corresponds to 100% certification load. These pulls at 80% Risoe load were repeated and the results from these pulls were compared. The blade was reinforced according to a Risoe DTU invention, where the trailing edge panels are coupled. The coupling is implemented to prevent the out of plane deformations and to reduce peeling stresses in the adhesive joints. Test results from measurements with the reinforcement have been compared to results without the coupling. The report presents only the relevant results for the 80% Risoe load and the results applicable for the investigation of the influence of the invention on the profile deformation. (Author)

  7. Analysis of extreme wind events at Høvsøre and the effect on wind turbine loads

    DEFF Research Database (Denmark)

    Hannesdóttir, Ásta; Kelly, Mark C.; Mann, Jakob

    of this analysis is to answer the questions: 1. How are the wind-turbine loads affected by these events? 2. What atmospheric parameters give rise to the highest loads? The data used for the analysis is from a 160 m tall lighting tower in Høvsøre, which is a measurement site approximately 2 km from the west coast...

  8. Dynamic loads caused by pressure blasts, steam explosions, and earth quakes; Dynamische Belastungen durch Druckstoesse, Dampfexplosionen und Erdbeben

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, H.H. [SDK Ingenieurunternehmen GmbH, Basel (Switzerland)

    1998-11-01

    The paper deals with description of structures and the relevant dynamic loads. As to the structures, gas, fluid, or solid structures are to be considered. They determine the characteristic vibrational behaviour of the structures in the interconnected system. The excitation type determines the component that will be induced to change characteristic vibrational behaviour of the structure, depending on the load increasing time and the period of excitation. Three examples are given to illustrate the processes. (Water tank subject to quasi-seismic conditions; pipeline affected by blow-down; shut-off valve for a pipe). (orig./CB) [Deutsch] In diesem Beitrag soll auf die Erfassung der Strukturen und die Erfassung der dynamischen Belastungen eingegangen werden. Zur Erfassung der Strukturen sind `Gas-, Fluid- und Festkoerper-Strukturen` zu beachten. Sie bestimmen das Eigenschwingverhalten im Verbund. Die Erregung bestimmt nun, welcher Bereich aus dem Eigen-Schwingverhalten der Struktur ueber die Lastanstiegs-Zeit und die Zeitdauer der Erregung anregbar ist. Drei Beispiele sollen die Aufgabenstellung erlaeutern (Wasserbehaelter unter erdbebenaehnlichen Bedingungen; Rohrleitung unter `Blow-down-Belastung`; Absperrklappe fuer eine Rohrleitung). (orig./MM)

  9. Prognostic factors for specific lower extremity and spinal musculoskeletal injuries identified through medical screening and training load monitoring in professional football (soccer): a systematic review

    Science.gov (United States)

    Sergeant, Jamie C; Parkes, Matthew J; Callaghan, Michael J

    2017-01-01

    Background Medical screening and load monitoring procedures are commonly used in professional football to assess factors perceived to be associated with injury. Objectives To identify prognostic factors (PFs) and models for lower extremity and spinal musculoskeletal injuries in professional/elite football players from medical screening and training load monitoring processes. Methods The MEDLINE, AMED, EMBASE, CINAHL Plus, SPORTDiscus and PubMed electronic bibliographic databases were searched (from inception to January 2017). Prospective and retrospective cohort studies of lower extremity and spinal musculoskeletal injury incidence in professional/elite football players aged between 16 and 40 years were included. The Quality in Prognostic Studies appraisal tool and the modified Grading of Recommendations Assessment, Development and Evaluation synthesis approach was used to assess the quality of the evidence. Results Fourteen studies were included. 16 specific lower extremity injury outcomes were identified. No spinal injury outcomes were identified. Meta-analysis was not possible due to heterogeneity and study quality. All evidence related to PFs and specific lower extremity injury outcomes was of very low to low quality. On the few occasions where multiple studies could be used to compare PFs and outcomes, only two factors demonstrated consensus. A history of previous hamstring injuries (HSI) and increasing age may be prognostic for future HSI in male players. Conclusions The assumed ability of medical screening tests to predict specific musculoskeletal injuries is not supported by the current evidence. Screening procedures should currently be considered as benchmarks of function or performance only. The prognostic value of load monitoring modalities is unknown. PMID:29177074

  10. Batch Blast Extractor: an automated blastx parser application.

    Science.gov (United States)

    Pirooznia, Mehdi; Perkins, Edward J; Deng, Youping

    2008-09-16

    BLAST programs are very efficient in finding similarities for sequences. However for large datasets such as ESTs, manual extraction of the information from the batch BLAST output is needed. This can be time consuming, insufficient, and inaccurate. Therefore implementation of a parser application would be extremely useful in extracting information from BLAST outputs. We have developed a java application, Batch Blast Extractor, with a user friendly graphical interface to extract information from BLAST output. The application generates a tab delimited text file that can be easily imported into any statistical package such as Excel or SPSS for further analysis. For each BLAST hit, the program obtains and saves the essential features from the BLAST output file that would allow further analysis. The program was written in Java and therefore is OS independent. It works on both Windows and Linux OS with java 1.4 and higher. It is freely available from: http://mcbc.usm.edu/BatchBlastExtractor/

  11. Explosive Blast Neuropathology and Seizures

    Directory of Open Access Journals (Sweden)

    S. Krisztian eKovacs

    2014-04-01

    Full Text Available Traumatic brain injury (TBI due to explosive blast exposure is a leading combat casualty. It is also implicated as a key contributor to war related mental health diseases. A clinically important consequence of all types of TBI is a high risk for development of seizures and epilepsy. Seizures have been reported in patients who have suffered blast injuries in the Global War on Terror but the exact prevalence is unknown. The occurrence of seizures supports the contention that explosive blast leads to both cellular and structural brain pathology. Unfortunately, the exact mechanism by which explosions cause brain injury is unclear, which complicates development of meaningful therapies and mitigation strategies. To help improve understanding, detailed neuropathological analysis is needed. For this, histopathological techniques are extremely valuable and indispensable. In the following we will review the pathological results, including those from immunohistochemical and special staining approaches, from recent preclinical explosive blast studies.

  12. Evaluation of protection systems for the lower extremity against the shock and blast effects resulting from anti-personnel mines using the Surrogate Lower Leg (SLL)

    CSIR Research Space (South Africa)

    Smit, E

    2012-10-01

    Full Text Available is in good agreement with the injury criteria reported in Figure 2. Figure 5: Post-blast autopsy results of the SLL for small, medium and large a/p landmine detonations REFERENCES [1] Landmine Cluster and Munition Monitor, (2010). ?Mine, Explosive... Remnants of War (ERW) and Cluster Submunition Casualties in 2010?. Available from: http://www.the-monitor.org/index.php/publications/ display?url=cmm/2011/maps/casualties.html [2] Smith A., (2009). ?The Database of Demining Incidents?. Geneva...

  13. Comparative analysis of methods for modelling the short-term probability distribution of extreme wind turbine loads

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    2016-01-01

    extrapolation techniques: the Weibull, Gumbel and Pareto distributions and a double-exponential asymptotic extreme value function based on the ACER method. For the successful implementation of a fully automated extrapolation process, we have developed a procedure for automatic identification of tail threshold...

  14. Effects of force load, muscle fatigue and extremely low frequency magnetic stimulation on EEG signals during side arm lateral raise task.

    Science.gov (United States)

    Wang, Ying; Cao, Liu; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Chen, Fei; Zheng, Dingchang

    2017-05-01

    This study was to quantitatively investigate the effects of force load, muscle fatigue and extremely low frequency (ELF) magnetic stimulation on electroencephalography (EEG) signal features during side arm lateral raise task. EEG signals were recorded by a BIOSEMI Active Two system with Pin-Type active-electrodes from 18 healthy subjects when they performed the right arm side lateral raise task (90° away from the body) with three different loads (0 kg, 1 kg and 3 kg; their order was randomized among the subjects) on the forearm. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as non-fatigue status and the last 10 s before the subject was exhausted as fatigue status. The subject was then given a 5 min resting between different loads. Two days later, the same experiment was performed on each subject except that ELF magnetic stimulation was applied to the subject's deltoid muscle during the 5 min resting period. EEG features from C3 and C4 electrodes including the power of alpha, beta and gamma and sample entropy were analyzed and compared between different loads, non-fatigue/fatigue status, and with/without ELF magnetic stimulation. The key results were associated with the change of the power of alpha band. From both C3-EEG and C4-EEG, with 1 kg and 3 kg force loads, the power of alpha band was significantly smaller than that from 0 kg for both non-fatigue and fatigue periods (all p    0.05 for all the force loads except C4-EEG with ELF simulation). The power of alpha band at fatigue status was significantly increased for both C3-EEG and C4-EEG when compared with the non-fatigue status (p  EEG). With magnetic stimulation, the powers of alpha from C3-EEG and C4-EEG were significantly decreased than without stimulation (all p    0.05, except between non-fatigue and fatigue with magnetic stimulation in gamma band of C3-EEG at 1 kg, and in the SampEn at 1

  15. Extreme Value Predictions for Wave- and Wind-induced Loads on Floating Offshore Wind Turbines using FORM

    DEFF Research Database (Denmark)

    Joensen, Sunvard; Jensen, Jørgen Juncher; Mansour, Alaa E.

    2007-01-01

    probable wave episodes leading to given re-sponses. As an example the motions of floating foundations for offshore wind turbines are analysed taking into consid-eration both the wave and wind induced loads and con-sidering different mooring systems. The possible large horizontal motions make it important...

  16. Spatial reliability analysis of a wind turbine blade cross section subjected to multi-axial extreme loading

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov; Bitsche, Robert; Blasques, José Pedro Albergaria Amaral

    2017-01-01

    This paper presents a methodology for structural reliability analysis of wind turbine blades. The study introduces several novel elements by taking into account loading direction using a multiaxial probabilistic load model, considering random material strength, spatial correlation between material...... properties, progressive material failure, and system reliability effects. An example analysis of reliability against material failure is demonstrated for a blade cross section. Based on the study we discuss the implications of using a system reliability approach, the effect of spatial correlation length......, type of material degradation algorithm, and reliability methods on the system failure probability, as well as the main factors that have an influence on the reliability. (C) 2017 Elsevier Ltd. All rights reserved....

  17. Position of the pelvis, lower extremities load and the arch of the feet in young adults who are physically active

    Directory of Open Access Journals (Sweden)

    Agnieszka Jankowicz-Szymańska

    2013-10-01

    Full Text Available Introduction: Body posture is an individual motion habit. It is variable and depends on the gender, age, structure of the body but also on mental and physical state. Although it is difficult to formulate a universal definition of correct body posture, the opinion that its elementary feature is symmetry is beyond any doubt. Such symmetry is related to the position of particular anatomical points and effects of static and dynamic forces. Aim of the research: To assess the relations between the pelvis position in the frontal plane, the static load on the lower limbs and architecture of the feet. The following features were analysed in a group of young, healthy and particularly physically active women and men: the frequency of asymmetry related to pelvis position, the load on the lower limbs related to body weight and foot architecture. Material and methods: The study group consisted of 100 students of physical education. To assess the position of the pelvis a palpable-visual method was used. Clarke’s method was applied to characterize the foot architecture determined by the position of standing with one leg on the CQ Elektronik podoscope. The static load on the lower limbs was assessed using the stabilographic platform EMILDUE from Technomex. Results : Collected data and observations show frequent asymmetric changes of pelvis position in the frontal plane and incorrect balance of the body in the standing position. The change of static load on the lower limbs influences the longitudinal architecture of the feet and this influence is statistically significant. Increased asymmetry of the pelvis in the frontal plane is related to profound disorder of body balance. Conclusions : Asymmetric position of the pelvis is associated with asymmetric arching of the feet and asymmetric body weight distribution. Full symmetric position of the pelvis is rare even among young people who are physically active.

  18. Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

    DEFF Research Database (Denmark)

    Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

    2015-01-01

    Fusing predictions from multiple simulators in the early stages of the conceptual design of a wind turbine results in reduction in model uncertainty and risk mitigation. Aero-servo-elastic is a term that refers to the coupling of wind inflow, aerodynamics, structural dynamics and controls. Fusing...... the response data from multiple aero-servo-elastic simulators could provide better predictive ability than using any single simulator. The co-Kriging approach to fuse information from multifidelity aero-servo-elastic simulators is presented. We illustrate the co-Kriging approach to fuse the extreme flapwise...

  19. Effect of sound stimulion reciprocal interaction of antagonist muscles of lowe extremities in humans under vestibular loadе

    Directory of Open Access Journals (Sweden)

    I. V. Dregval

    2015-05-01

    Full Text Available Results of the research are evidence of changing muscles reflex activity of human lower extremity under the influence of sound stimulus of various frequency range together with the vestibular burden. The most change of the H-reflex was observed under the sound stimulus of 800 hertz. Not only the proprioceptive but auditory sensory system takes part in the regulation of the brain reflex activity. Existence of different labyrinths actions, according to the situation, on the interneuronic inhibitory ways of the postsynaptic inhibition of the salens muscle’s motoneurons is supposed.

  20. Variation of Extreme and Fatigue Design Loads on the Main Bearing of a Front Mounted Direct Drive System

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Natarajan, Anand

    The drivetrain of a 10 MW wind turbine has been designed as a direct drive transmission with a superconducting generator mounted in front of the hub and connected to the main frame through a King-pin stiff assembly by DNV-GL. The aeroelastic design loads of such an arrangement are evaluated based...... train. A weight reduction of 50% is needed in order to maintain main bearing fatigue damage equivalent to the reference drive train. Thus a target mass of front mounted superconducting direct drive generators is found to be between 183-272 tons....

  1. Variation of Extreme and Fatigue Design Loads on the Main Bearing of a Front Mounted Direct Drive System

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Natarajan, Anand

    2016-01-01

    The drivetrain of a 10 MW wind turbine has been designed as a direct drive transmission with a superconducting generator mounted in front of the hub and connected to the main frame through a King-pin stiff assembly by DNV-GL. The aeroelastic design loads of such an arrangement are evaluated based...... train. A weight reduction of 50% is needed in order to maintain main bearing fatigue damage equivalent to the reference drive train. Thus a target mass of front mounted superconducting direct drive generators is found to be between 183-272 tons....

  2. Batch Blast Extractor: an automated blastx parser application

    Science.gov (United States)

    Pirooznia, Mehdi; Perkins, Edward J; Deng, Youping

    2008-01-01

    Motivation BLAST programs are very efficient in finding similarities for sequences. However for large datasets such as ESTs, manual extraction of the information from the batch BLAST output is needed. This can be time consuming, insufficient, and inaccurate. Therefore implementation of a parser application would be extremely useful in extracting information from BLAST outputs. Results We have developed a java application, Batch Blast Extractor, with a user friendly graphical interface to extract information from BLAST output. The application generates a tab delimited text file that can be easily imported into any statistical package such as Excel or SPSS for further analysis. For each BLAST hit, the program obtains and saves the essential features from the BLAST output file that would allow further analysis. The program was written in Java and therefore is OS independent. It works on both Windows and Linux OS with java 1.4 and higher. It is freely available from: PMID:18831775

  3. A Parametric Approach to Shape Field-Relevant Blast Wave Profiles in Compressed-Gas-Driven Shock Tube

    OpenAIRE

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse a...

  4. An assessment of the response of Military lower extremity and Hybrid III leg during typical blast impact using the Hybrid III and EUROSID-2 ATD.

    CSIR Research Space (South Africa)

    Pandelani, T

    2014-09-01

    Full Text Available This paper presents the evaluation of the injury measurement response of the Hybrid III and ES2re ATD’s using both the HIII and MiL-Lx instrumented lower legs as loaded by the Modified Lower Limb Impactor (MLLI)....

  5. Material Systems for Blast-Energy Dissipation

    Energy Technology Data Exchange (ETDEWEB)

    James Schondel; Henry S. Chu

    2010-10-01

    Lightweight panels have been designed to protect buildings and vehicles from blast pressures by activating energy dissipation mechanisms under the influence of blast loading. Panels were fabricated which featured a variety of granular materials and hydraulic dissipative deformation mechanisms and the test articles were subjected to full-scale blast loading. The force time-histories transmitted by each technology were measured by a novel method that utilized inexpensive custom-designed force sensors. The array of tests revealed that granular materials can effectively dissipate blast energy if they are employed in a way that they easily crush and rearrange. Similarly, hydraulic dissipation can effectively dissipate energy if the panel features a high fraction of porosity and the panel encasement features low compressive stiffness.

  6. Effects of Filtering on Experimental Blast Overpressure Measurements.

    Science.gov (United States)

    Alphonse, Vanessa D; Kemper, Andrew R; Duma, Stefan M

    2015-01-01

    When access to live-fire test facilities is limited, experimental studies of blast-related injuries necessitate the use of a shock tube or Advanced Blast Simulator (ABS) to mimic free-field blast overpressure. However, modeling blast overpressure in a laboratory setting potentially introduces experimental artifacts in measured responses. Due to the high sampling rates required to capture a blast overpressure event, proximity to alternating current (AC-powered electronics) and poorly strain-relieved or unshielded wires can result in artifacts in the recorded overpressure trace. Data in this study were collected for tests conducted on an empty ABS (“Empty Tube”) using high frequency pressure sensors specifically designed for blast loading rates (n=5). Additionally, intraocular overpressure data (“IOP”) were collected for porcine eyes potted inside synthetic orbits located inside the ABS using an unshielded miniature pressure sensor (n=3). All tests were conducted at a 30 psi static overpressure level. A 4th order phaseless low pass Butterworth software filter was applied to the data. Various cutoff frequencies were examined to determine if the raw shock wave parameters values could be preserved while eliminating noise and artifacts. A Fast Fourier Transform (FFT) was applied to each test to examine the frequency spectra of the raw and filtered signals. Shock wave parameters (time of arrival, peak overpressure, positive duration, and positive impulse) were quantified using a custom MATLAB® script. Lower cutoff frequencies attenuated the raw signal, effectively decreasing the peak overpressure and increasing the positive duration. Rise time was not preserved the filtered data. A CFC 6000 filter preserved the remaining shock wave parameters within ±2.5% of the average raw values for the Empty Tube test data. A CFC 7000 filter removed experimental high-frequency artifacts and preserved the remaining shock wave parameters within ±2.5% of the average raw values for

  7. Experimental Study and Engineering Practice of Pressured Water Coupling Blasting

    Directory of Open Access Journals (Sweden)

    J. X. Yang

    2017-01-01

    Full Text Available Overburden strata movement in large space stope is the major reason that induces the appearance of strong mining pressure. Presplitting blasting for hard coal rocks is crucial for the prevention and control of strong pressure in stope. In this study, pressured water coupling blasting technique was proposed. The process and effect of blasting were analyzed by orthogonal test and field practice. Results showed that the presence of pressure-bearing water and explosive cartridges in the drill are the main influence factors of the blasting effect of cement test block. The high load-transmitting performance of pore water and energy accumulation in explosive cartridges were analyzed. Noxious substances produced during the blasting process were properly controlled because of the moistening, cooling, and diluting effect of pore water. Not only the goal of safe and static rock fragmentation by high-explosive detonation but also a combination of superdynamic blast loading and static loading effect of the pressured water was achieved. Then the practice of blasting control of hard coal rocks in Datong coal mine was analyzed to determine reasonable parameters of pressured water coupling blasting. A good presplitting blasting control effect was achieved for the hard coal rocks.

  8. Imaging of lower extremity trauma from Boston Marathon bombing.

    Science.gov (United States)

    Konwinski, Ryan R; Singh, Ajay; Soto, Jorge

    2016-10-01

    The goal of this study is to describe the imaging features of lower extremity blast injuries in patients encountered in the radiology departments from the Boston Marathon bombings. A total of 115 patients presented to four acute care hospitals on April 15, 2013, 43 of whom presented with lower extremity injuries and were included in this study. The imaging findings of primary, secondary, tertiary, and quaternary blast injuries were evaluated. Forty-one of 43 patients sustained secondary blast injuries to the lower extremities with 31 patients (70 %) having retained shrapnel, seven patients (16 %) having soft tissue lacerations without retained shrapnel, and ten patients (23 %) having lower extremity amputation (7 % double amputees). Eight of these patients (20 %) had lower extremity fractures, and five patients (12 %) had vascular injuries. Two of the 43 patients (5 %) had only tertiary injuries, and five of 43 patients (12 %) were noted to have lower extremity burns, consistent with quaternary blast injury. No primary blast injury occurred in the lower extremities. A vast majority of lower extremity injuries were from secondary blast injury, most commonly from retained shrapnel in 70 % of patients and 23 % of patients sustaining lower extremity amputation. Retained shrapnel in the lower extremity was most commonly ball bearings and pressure cooker fragments, and most injuries affected the leg, followed by the thigh and foot.

  9. Blast Waves

    CERN Document Server

    Needham, Charles E

    2010-01-01

    The primary purpose of this text is to document many of the lessons that have been learned during the author’s more than forty years in the field of blast and shock. The writing therefore takes on an historical perspective, in some sense, because it follows the author’s experience. The book deals with blast waves propagating in fluids or materials that can be treated as fluids. It begins by distinguishing between blast waves and the more general category of shock waves. It then examines several ways of generating blast waves, considering the propagation of blast waves in one, two and three dimensions as well as through the real atmosphere. One section treats the propagation of shocks in layered gases in a more detailed manner. The book also details the interaction of shock waves with structures in particular reflections, progressing from simple to complex geometries, including planar structures, two-dimensional structures such as ramps or wedges, reflections from heights of burst, and three-dimensional st...

  10. Equipment Specific Optimum Blast-Design Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Rahul Upadhyay

    2015-08-01

    Full Text Available Design of blasting parameters plays an important role in the optimization of mining cost as well as cost of subsequent processing of ore. Drilling and handling costs are the major mining cost. This work presents an indirect optimization model for mining cost through optimization of blasting parameters for a particular set of drilling and loading equipment.

  11. Blast event simulation for a vehicle subjected to an explosion

    NARCIS (Netherlands)

    Zhang, G.; Vlahopoulos, N.; Goetz, R.; Velde, R. van de

    2007-01-01

    One of the main threats to military vehicles originates from blasts. In order to improve the survivability of the occupants it is important to design a military vehicle for increased occupant safety. Simulation technology that combines modeling of the blast loads from an explosion, the response of

  12. Study of connected system of automatic control of load and operation efficiency of a steam boiler with extremal controller on a simulation model

    Science.gov (United States)

    Sabanin, V. R.; Starostin, A. A.; Repin, A. I.; Popov, A. I.

    2017-02-01

    The problems of operation effectiveness increase of steam boilers are considered. To maintain the optimum fuel combustion modes, it is proposed to use an extremal controller (EC) determining the value of airflow rate, at which the boiler generating the desired amount of heat will consume a minimum amount of fuel. EC sets the determined value of airflow rate to airflow rate controller (ARC). The test results of numerical simulation dynamic nonlinear model of steam boiler with the connected system of automatic control of load and combustion efficiency using EC are presented. The model is created in the Simulink modeling package of MATLAB software and can be used to optimize the combustion modes. Based on the modeling results, the conclusion was drawn about the possibility in principle of simultaneously boiler load control and optimizing by EC the combustion modes when changing the fuel combustion heat and the boiler characteristics and its operating mode. It is shown that it is possible to automatically control the operation efficiency of steam boilers when using EC without applying the standard flue gas analyzers. The article considers the numerical simulation dynamic model of steam boiler with the schemes of control of fuel consumption and airflow rate, the steam pressure and EC; the purpose of using EC in the scheme with linear controllers and the requirements to the quality of its operation; the results of operation of boiler control schemes without EC with estimation of influence of roughness of thermal mode maps on the nature of static and dynamic connection of the control units of fuel consumption and airflow rate; the phase trajectories and the diagrams of transient processes occurring in the control scheme with EC with stepped changing the fuel quality and boiler characteristics; analysis of modeling results and prospects for using EC in the control schemes of boilers.

  13. Evolution of blast wave profiles in simulated air blasts: experiment and computational modeling

    Science.gov (United States)

    Chandra, N.; Ganpule, S.; Kleinschmit, N. N.; Feng, R.; Holmberg, A. D.; Sundaramurthy, A.; Selvan, V.; Alai, A.

    2012-09-01

    Shock tubes have been extensively used in the study of blast traumatic brain injury due to increased incidence of blast-induced neurotrauma in Iraq and Afghanistan conflicts. One of the important aspects in these studies is how to best replicate the field conditions in the laboratory which relies on reproducing blast wave profiles. Evolution of the blast wave profiles along the length of the compression-driven air shock tube is studied using experiments and numerical simulations with emphasis on the shape and magnitude of pressure time profiles. In order to measure dynamic pressures of the blast, a series of sensors are mounted on a cylindrical specimen normal to the flow direction. Our results indicate that the blast wave loading is significantly different for locations inside and outside of the shock tube. Pressure profiles inside the shock tube follow the Friedlander waveform fairly well. Upon approaching exit of the shock tube, an expansion wave released from the shock tube edges significantly degrades the pressure profiles. For tests outside the shock tube, peak pressure and total impulse reduce drastically as we move away from the exit and majority of loading is in the form of subsonic jet wind. In addition, the planarity of the blast wave degrades as blast wave evolves three dimensionally. Numerical results visually and quantitatively confirm the presence of vortices, jet wind and three-dimensional expansion of the planar blast wave near the exit. Pressure profiles at 90° orientation show flow separation. When cylinder is placed inside, this flow separation is not sustained, but when placed outside the shock tube this flow separation is sustained which causes tensile loading on the sides of the cylinder. Friedlander waves formed due to field explosives in the intermediate-to far-field ranges are replicated in a narrow test region located deep inside the shock tube.

  14. Improvement of loading and transport bodies of tunneling machines

    Science.gov (United States)

    Nosenko, A. S.; Isakov, V. S.; Domnitskiy, A. A.; Shemshura, E. A.; Zubov, V. V.

    2017-10-01

    The article discusses the use of sets of equipment for mining and construction of road tunnels with the use of a self-propelled vehicle and bunker loaders to transport the mined rock. A patented design of the tunneling combine loading body, which allows adjusting its performance and power consumption in the loading mode, is considered. Reducing stress in extreme situations will make it possible to avoid overloading the drive and increase the reliability of the combine as a whole. The scheme of one of the most promising variants of the wedge bunker loader with variable geometry of the conveying elements is presented. The proposed design solves the problem of “locking” the material in narrow parts of the conveying body or in places where loading and transport bodies of different width are connected, as well as in the blast-and-heap mode of the loader.

  15. A Fluid Helmet Liner for Protection Against Blast Induced Traumatic Brain Injury

    Science.gov (United States)

    2010-05-01

    using the model. Because ABAQUS • is not tailored specifically to air blast loading simulations, effort has gone into verifying that the software can...indeed, model a blast wave. Using ABAQUS • makes it relatively easy to modify loading conditions and part geometries and easy to extract quantities of...It describes a method for placing a partially evacuated chamber filled with air or another gas between the blast source and the object to be

  16. An in situ simultaneous measurement system combining photoelasticity and caustics methods for blast-induced dynamic fracture

    Science.gov (United States)

    Qiu, Peng; Yue, Zhongwen; Zhang, Shichun; Li, Zhanfei

    2017-11-01

    Photoelasticity and caustics methods are extensively used in the history of dynamic fracture mechanics. However, there is little work for the combination of them in the same experiment associated with high loading rate in extreme conditions. In the present work, it is the first time to build a simultaneous measurement system which can use photoelasticity and caustics methods at the same instant for in situ optical investigations of blast-induced dynamic fracture. To illustrate the capability of this system, an explosion experiment using a 2D epoxy plate is conducted, yielding consistent results between two methods. This novel system provides rich experimental data including local-field information for the crack tip and full-field information for blasting waves.

  17. Mesh considerations for finite element blast modelling in biomechanics.

    Science.gov (United States)

    Panzer, Matthew B; Myers, Barry S; Bass, Cameron R

    2013-01-01

    Finite element (FE) modelling is a popular tool for studying human body response to blast exposure. However, blast modelling is a complex problem owing to more numerous fluid-structure interactions (FSIs) and the high-frequency loading that accompanies blast exposures. This study investigates FE mesh design for blast modelling using a sphere in a closed-ended shock tube meshed with varying element sizes using both tetrahedral and hexahedral elements. FSI was consistent for sphere-to-fluid element ratios between 0.25 and 4, and acceleration response was similar for both element types (R(2) = 0.997). Tetrahedral elements were found to become increasingly volatile following shock loading, causing higher pressures and stresses than predicted with the hexahedral elements. Deviatoric stress response was dependent on the sphere mesh size (p tube mesh size (p blast models.

  18. The Pre-Blast Concept for use on Armour Materials

    Science.gov (United States)

    2016-02-01

    explosion technique to obtain UFG is investigated. The technique involves hardening of materials by sheet charge blast loading. Steels investigated...plates were blast loaded by a sheet charge (Figure 2) prior to the explosion bulge test. The thickness of the sheet charge was varied in 2 mm...evidence of cracking in the armour steels and Crack-starter explosion bulge testing of the armour steels at -18 ºC demonstrated that the steels have

  19. Development of a Liquid Blast Tube Facility for Material Testing

    Science.gov (United States)

    Samuelraj, I. Obed; Jagadeesh, G.

    The feasibility of mitigating blast/shock loads using materials such as composites and foams is well known. In order to study their attenuation characteristics and to optimize the mitigation of such loads, use of shock tube to generate an exponentially decaying pressure profile (called blast tube here) is a popular technique. Shock waves in liquids (e.g., water), particularly, are capable of meeting this requirement as they are stronger and also uniform [1].

  20. Extramedullary blast crisis of chronic myelogenous leukemia as an initial presentation☆

    Science.gov (United States)

    Tsukamoto, Shokichi; Ota, Satoshi; Ohwada, Chikako; Takeda, Yusuke; Takeuchi, Masahiro; Sakaida, Emiko; Shimizu, Naomi; Yokote, Koutaro; Iseki, Tohru; Nakaseko, Chiaki

    2013-01-01

    Extramedullary blast crisis of chronic myelogenous leukemia (CML) is defined as the development of extramedullary disease caused by the infiltration of blasts regardless of proliferation of blasts in the bone marrow. The onset of extramedullary blast crisis in the newly diagnosed patients is known to be extremely rare. Here, we present a case of extramedullary blast crisis of CML as an initial presentation in a 17-year-old female presenting with pain in the left femur tumor. This case was treated successfully with dasatinib and allogeneic hematopoietic stem cell transplantation, with achievement of long-term remission. PMID:24371785

  1. The experimental and theoretical investigations of damage development and distribution in double-forged tungsten under plasma irradiation-initiated extreme heat loads

    Directory of Open Access Journals (Sweden)

    Väli Berit

    2016-06-01

    Full Text Available The influence of extreme heat loads, as produced by a multiple pulses of non-homogeneous fl ow of slow plasma (0.1-1 keV and fast ions (100 keV, on double-forged tungsten (DFW was investigated. For generation of deuterium plasma and fast deuterons, plasma-focus devices PF-12 and PF-1000 are used. Depending on devices and conditions, the power flux density of plasma varied in a range of 107-1010 W/cm2 with pulse duration of 50-100 ns. Power flux density of fast ions was 1010-1012 W/cm2 at the pulse duration of 10-50 ns. To achieve the combined effect of different kind of plasmas, the samples were later irradiated with hydrogen plasma (105 W/cm2, 0.25 ms by a QSPA Kh-50 plasma generator. Surface modification was analysed by scanning electron microscopy (SEM and microroughness measurements. For estimation of damages in the bulk of material, an electrical conductivity method was used. Investigations showed that irradiation of DFW with multiple plasma pulses generated a mesh of micro- and macrocracks due to high heat load. A comparison with single forged tungsten (W and tungsten doped with 1% lanthanum-oxide (WL10 reveals the better crack-resistance of DFW. Also, sizes of cells formed between the cracks on the DFW’s surface were larger than in cases of W or WL10. Measurements of electrical conductivity indicated a layer of decreased conductivity, which reached up to 500 μm. It depended mainly on values of power flux density of fast ions, but not on the number of pulses. Thus, it may be concluded that bulk defects (weakening bonds between grains and crystals, dislocations, point-defects were generated due to mechanical shock wave, which was generated by the fast ions flux. Damages and erosion of materials under different combined radiation conditions have also been discussed.

  2. Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

    Directory of Open Access Journals (Sweden)

    Shu Yang

    2013-01-01

    Full Text Available Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes force enhancement and results in much worse crew injury. An isolating layer between the aluminum foam and the vehicle floor is introduced to remediate this drawback. The results show that the blast-resistant capability of the innovative sandwich armor structure with the isolating layer increases remarkably.

  3. Tailoring the Blast Exposure Conditions in the Shock Tube for Generating Pure, Primary Shock Waves: The End Plate Facilitates Elimination of Secondary Loading of the Specimen.

    Science.gov (United States)

    Kuriakose, Matthew; Skotak, Maciej; Misistia, Anthony; Kahali, Sudeepto; Sundaramurthy, Aravind; Chandra, Namas

    2016-01-01

    The end plate mounted at the mouth of the shock tube is a versatile and effective implement to control and mitigate the end effects. We have performed a series of measurements of incident shock wave velocities and overpressures followed by quantification of impulse values (integral of pressure in time domain) for four different end plate configurations (0.625, 2, 4 inches, and an open end). Shock wave characteristics were monitored by high response rate pressure sensors allocated in six positions along the length of 6 meters long 229 mm square cross section shock tube. Tests were performed at three shock wave intensities, which was controlled by varying the Mylar membrane thickness (0.02, 0.04 and 0.06 inch). The end reflector plate installed at the exit of the shock tube allows precise control over the intensity of reflected waves penetrating into the shock tube. At the optimized distance of the tube to end plate gap the secondary waves were entirely eliminated from the test section, which was confirmed by pressure sensor at T4 location. This is pronounced finding for implementation of pure primary blast wave animal model. These data also suggest only deep in the shock tube experimental conditions allow exposure to a single shock wave free of artifacts. Our results provide detailed insight into spatiotemporal dynamics of shock waves with Friedlander waveform generated using helium as a driver gas and propagating in the air inside medium sized tube. Diffusion of driver gas (helium) inside the shock tube was responsible for velocity increase of reflected shock waves. Numerical simulations combined with experimental data suggest the shock wave attenuation mechanism is simply the expansion of the internal pressure. In the absence of any other postulated shock wave decay mechanisms, which were not implemented in the model the agreement between theory and experimental data is excellent.

  4. Alternative Ii-independent antigen-processing pathway in leukemic blasts involves TAP-dependent peptide loading of HLA class II complexes

    NARCIS (Netherlands)

    van Luijn, M.M.; Chamuleau, M.E.D.; Ressing, M.E.; Wiertz, E.J.; Ostrand-Rosenberg, S.; Souwer, Y.; Zevenbergen, A.; Ossenkoppele, G.J.; van de Loosdrecht, A.A.; Ham, S.M.

    2010-01-01

    During HLA class II synthesis in antigen-presenting cells, the invariant chain (Ii) not only stabilizes HLA class II complexes in the endoplasmic reticulum, but also mediates their transport to specialized lysosomal antigen-loading compartments termed MIICs. This study explores an alternative HLA

  5. The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na+ loading in xylem and confers salt tolerance in transgenic tobacco

    Directory of Open Access Journals (Sweden)

    Yadav Narendra

    2012-10-01

    Full Text Available Abstract Background Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1 gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. Results The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC, chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Conclusions Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other

  6. Modelling and Testing of Blast Effect On the Structures

    Science.gov (United States)

    Figuli, Lucia; Jangl, Štefan; Papán, Daniel

    2016-10-01

    As a blasting agent in the blasting and mining engineering, has been using one of so called new generation of explosives which offer greater flexibility in their range and application, and such explosive is ANFO. It is type of explosive consists of an oxidiser and a fuel (ammonium nitrate and fuel oil). One of such ANFO explosives which are industrially made in Slovakia is POLONIT. The explosive is a mixture of ammonium nitrate, methyl esters of higher fatty acids, vegetable oil and red dye. The paper deals with the analysis of structure subjected to the blast load created by the explosion of POLONIT charge. First part of paper is describing behaviour and characteristic of blast wave generated from the blast (detonation characteristics, physical characteristics, time-history diagram etc.) and the second part presents the behaviour of such loaded structures, because of the analysis of such dynamical loaded structure is required knowing the parameters of blast wave, its effect on structure and the tools for the solution of dynamic analysis. The real field tests of three different weight of charges and two different structures were done. The explosive POLONIT was used together with 25 g of ignition explosive PLNp10. Analytical and numerical model of blast loaded structure is compared with the results obtained from the field tests (is compared with the corresponding experimental accelerations). For the modelling structures were approximated as a one-degree system of freedom (SDOF), where the blast wave was estimated with linear decay and exponential decay using positive and negative phase of blast wave. Numerical solution of the steel beam dynamic response was performed via FEM (Finite Element Method) using standard software Visual FEA.

  7. Blast Simulation with Balloons Containing Detonable Gas.

    Science.gov (United States)

    1974-12-11

    to separate the gas components during the launch procedure for high altitude tests. The balloon is partially inflated at launch with methane in one...1 II LEONBL 24 irI GAS LOADING DU - GAS COMMUNICATION DUCT ACCESS DUCT DETONATOR SUPPORT L.INE \\. I ~~ GAS LOADING DUCT’’ BALLON E T BALLOON. Figure 2...rr DNA 3432F BLAST SIMULATION WITH BALLOONS CONTAINING DETONABLE GAS General American Research Division 7449 North Natchez Avenue Niles, Illinois

  8. New swine model of infected soft tissue blast injury.

    Science.gov (United States)

    Li, Jinqing; Topaz, Morris; Xun, Wenxing; Li, Wangzhou; Wang, Xiaolin; Liu, Haibo; Yuan, Yanqin; Chen, Shaozong; Li, Yuejun; Li, Xueyong

    2012-10-01

    War injuries, especially blast injuries, have a high risk of infection. However, no animal models of infected war injuries have been built in large animals, which retards both the understanding and the treatment optimization of infected war injuries. Soft tissue blast injuries were created by explosion of electric detonators in white domestic pigs. The ultra structure of the tissue around the wound was determined by transmission electron microscope. To develop infection of blast injury wounds, the pigs were housed in a standard animal house which was disinfected periodically, and the wounds were left untreated for 3 days. Wound specimens were collected daily to determine the bacterial load and bacterial components. To determine whether infection induces tissue necrosis in infected soft tissue blast injury wounds, uninfected blast injury wounds were created as controls of infected wounds by surgical debridement daily, and the wound area and wound depth of both wounds were measured. The wound area and the wound depth of the soft tissue blast injury created in this study fell in the range of human moderate soft tissue war injuries, and the ultra structure of the wounds was comparable with that of human blast injury wounds. The bacterial load of uninfected wounds was under 10 colony forming unit/g during the first 3 days of injury, while that of infected wounds was over 10 colony forming unit/g after 2 days of injury. The infected soft tissue blast injury wounds contained most of the bacteria frequently isolated in battlefield wounds. In addition, infection induced evident tissue necrosis in infected blast injury wounds. The infected soft tissue blast injury wounds mimic those in human, and they can be used to address key points of treatment optimization.

  9. Evaluation of blast-induced vibration effects on structures 1

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Rim; Jeon, Gyu Shick; Lee, Dae Soo; Joo, Kwang Ho; Lee, Woong Keon [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of); Ryu, Chang Ha; Chung, So Keul; Lee, Kyung Won; Shin, Hee Soon; Chun, Sun Woo; Park, Yeon Jun; Synn, Joong Ho; Choi, Byung Hee [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-31

    Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants to maintain the safety of structures and facilities in power plants. Our own standard for safety level of blast vibration is not prepared yet, and foreign standards have been generally employed without theoretical and experimental verification. Safety-related structures of power plants and facilities have to be protected against the effects of possible hazards due to blast vibration. Earthquakes have been considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibration are not. In order to ensure the safety, rational safe criterion should be established and blast design should be satisfy it, which requires the development of a model for prediction of vibration level through more systematic measurement and analysis. The main objectives of the study are : to provide background data for establishing the rational safe vibration limits, to develop models for prediction of blast vibration level, to establish safe blast design criterion, and to accumulate techniques for field measurements, data acquisition and analysis (author). 80 refs., 347 figs.

  10. The pathobiology of blast injuries and blast-induced neurotrauma as identified using a new experimental model of injury in mice.

    Science.gov (United States)

    Cernak, Ibolja; Merkle, Andrew C; Koliatsos, Vassilis E; Bilik, Justin M; Luong, Quang T; Mahota, Theresa M; Xu, Leyan; Slack, Nicole; Windle, David; Ahmed, Farid A

    2011-02-01

    Current experimental models of blast injuries used to study blast-induced neurotrauma (BINT) vary widely, which makes the comparison of the experimental results extremely challenging. Most of the blast injury models replicate the ideal Friedländer type of blast wave, without the capability to generate blast signatures with multiple shock fronts and refraction waves as seen in real-life conditions; this significantly reduces their clinical and military relevance. Here, we describe the pathophysiological consequences of graded blast injuries and BINT generated by a newly developed, highly controlled, and reproducible model using a modular, multi-chamber shock tube capable of tailoring pressure wave signatures and reproducing complex shock wave signatures seen in theater. While functional deficits due to blast exposure represent the principal health problem for today's warfighters, the majority of available blast models induces tissue destruction rather than mimic functional deficits. Thus, the main goal of our model is to reliably reproduce long-term neurological impairments caused by blast. Physiological parameters, functional (motor, cognitive, and behavioral) outcomes, and underlying molecular mechanisms involved in inflammation measured in the brain over the 30 day post-blast period showed this model is capable of reproducing major neurological changes of clinical BINT. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Locating Gases in Porous Materials: Cryogenic Loading of Fuel-Related Gases Into a Sc-based Metal-Organic Framework under Extreme Pressures.

    Science.gov (United States)

    Sotelo, Jorge; Woodall, Christopher H; Allan, Dave R; Gregoryanz, Eugene; Howie, Ross T; Kamenev, Konstantin V; Probert, Michael R; Wright, Paul A; Moggach, Stephen A

    2015-11-02

    An alternative approach to loading metal organic frameworks with gas molecules at high (kbar) pressures is reported. The technique, which uses liquefied gases as pressure transmitting media within a diamond anvil cell along with a single-crystal of a porous metal-organic framework, is demonstrated to have considerable advantages over other gas-loading methods when investigating host-guest interactions. Specifically, loading the metal-organic framework Sc2BDC3 with liquefied CO2 at 2 kbar reveals the presence of three adsorption sites, one previously unreported, and resolves previous inconsistencies between structural data and adsorption isotherms. A further study with supercritical CH4 at 3-25 kbar demonstrates hyperfilling of the Sc2 BDC3 and two high-pressure displacive and reversible phase transitions are induced as the filled MOF adapts to reduce the volume of the system. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Blast event simulation for a structure subjected to a landmine explosion

    NARCIS (Netherlands)

    Sun, J.; Vlahopoulos, N.; Stabryla, T.J.; Goetz, R.; Velde, R. van de

    2006-01-01

    One of the main threats to military vehicles originates from landmine blasts. In order to improve the survivability of the occupants it is important to design a military vehicle for increased occupant safety. Simulation technology that combines modeling of the blast loads from the landmine

  13. Response Mechanism: Blast/Fire Interactions.

    Science.gov (United States)

    1983-11-01

    blast waves. The excercise will be iterative in nature in that the postulated mechanisms attempt to explain and correlate the data while the data and...experiments are extremely difficult to control. Although a great deal of care is excercised by the SRI team In the conduct of these experiments and although...SWIP 2AW, ENGLAND Human Sciences Research, Inc. Westgate Industrial Park Edward J. Chapyak 7710 Old Springhouse Road Energy Division McLean, VA 22102

  14. Dry ice blasting

    Science.gov (United States)

    Lonergan, Jeffrey M.

    1992-04-01

    As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

  15. Simulations of Porcine Eye Exposure to Primary Blast Insult.

    Science.gov (United States)

    Watson, Richard; Gray, Walt; Sponsel, William E; Lund, Brian J; Glickman, Randolph D; Groth, Sylvia L; Reilly, Matthew A

    2015-08-01

    A computational model of the porcine eye was developed to simulate primary blast exposure. This model facilitates understanding of blast-induced injury mechanisms. A computational model of the porcine eye was used to simulate the effects of primary blast loading for comparison with experimental findings from shock tube experiments. The eye model was exposed to overpressure-time histories measured during physical experiments. Deformations and mechanical stresses within various ocular tissues were then examined for correlation with pathological findings in the experiments. Stresses and strains experienced in the eye during a primary blast event increase as the severity of the blast exposure increases. Peak stresses in the model occurred in locations in which damage was most often observed in the physical experiments. Blast injuries to the anterior chamber may be due to inertial displacement of the lens and ciliary body while posterior damage may arise due to contrecoup interactions of the vitreous and retina. Correlation of modeling predictions with physical experiments lends confidence that the model accurately represents the conditions found in the physical experiments. This computational model offers insights into the mechanisms of ocular injuries arising due to primary blast and may be used to simulate the effects of new protective eyewear designs.

  16. Effect of Stemming to Burden Ratio and Powder Factor on Blast Induced Rock Fragmentation- A Case Study

    Science.gov (United States)

    Prasad, Sandeep; Choudhary, B. S.; Mishra, A. K.

    2017-08-01

    Rock fragmentation size is very important parameters for economical point of view in any surface mining. Rock fragment size direct effects on the costs of drilling, blasting, loading, secondary blasting and crushing. The main purpose of this study is to investigate effect of blast design parameters such as burden, blast hole length, stemming length, and powder factor on rock fragmentation. The fragment sizes (MFS, K50, m), and maximum fragment size (K95, m) of rock were determined by using the computer software. For every blast, after blasting operation, the images of whole muck pile are captured and there images were used for fragmentation analysis by using the Fragalyst software. It was observed that the optimal fragment size (MFS, K50, m and maximum fragment size, K95, m) of rock depends strongly on the blast design parameters and explosive parameters.

  17. Glass-Fiber Networks as an Orbit for Ions: Fabrication of Excellent Antistatic PP/GF Composites with Extremely Low Organic Salt Loadings.

    Science.gov (United States)

    Gu, Senlin; Zhu, Leon; Mercier, Claude; Li, Yongjin

    2017-05-31

    Polypropylene (PP)/glass fiber (GF) composites showing excellent antistatic performance were prepared by a simple melt process blending PP with GF and a small amount of organic salts (OSs). Two types of OSs, tribuyl(octyl)phosphonium bis(trifloromethanesulfonyl)imide (TBOP-TFSI) and lithium bis(trifloromethanesulfonyl)imide (Li-TFSI), with equivalent anions were used as antistatic agents for the composites. It was found that the GF and OSs exhibited significant synergistic effects on the antistatic performance as well as the mechanical properties of the composites. On the one hand, the incorporation of GF significantly enhanced the electric conductivity of the composites at a constant OS loading. On the other hand, the two types of OSs improved the interfacial adhesion between the GF and the PP matrix, which led to an enhancement of the mechanical properties. This study showed that OSs had specific interactions with GFs and were absorbed exclusively on the GF surface. The GF network in the PP matrix provided perfect orbits for the movement of ions, inducing the excellent antistatic performance exhibited by the PP/GF composites at an OS loading of as low as 0.25 wt % when the GF formed a network in the PP matrix.

  18. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period [Corrigendum

    Directory of Open Access Journals (Sweden)

    Burke DT

    2014-02-01

    Full Text Available CorrigendumBurke DT, Tran D, Cui D, et al. Open Access J Sports Med. 2013;4:211–219.On page 212, second paragraph of the Methods section, line 3 from the bottom, "45 kg" should be "30%".On page 213, first column, lines 9, 22 and 34, "45 kg" should be "30%".Table 1 on page 214, data entered into the Chest column under Maximum loads lifted, kg was incorrect. The corrected table is shown below.View original paper by Burke and colleagues.

  19. Explosive signatures: Pre & post blast

    Science.gov (United States)

    Bernier, Evan Thomas

    Manuscripts 1 and 2 of this dissertation both involve the pre-blast detection of trace explosive material. The first manuscript explores the analysis of human hair as an indicator of exposure to explosives. Field analysis of hair for trace explosives is quick and non-invasive, and could prove to be a powerful linkage to physical evidence in the form of bulk explosive material. Individuals tested were involved in studies which required handling or close proximity to bulk high explosives such as TNT, PETN, and RDX. The second manuscript reports the results of research in the design and application of canine training aids for non-traditional, peroxide-based explosives. Organic peroxides such as triacetonetriperoxide (TATP) and hexamethylenetriperoxidediamine (HMTD) can be synthesized relatively easily with store-bought ingredients and have become popular improvised explosives with many terrorist groups. Due to the hazards of handling such sensitive compounds, this research established methods for preparing training aids which contained safe quantities of TATP and HMTD for use in imprinting canines with their characteristic odor. Manuscripts 3 and 4 of this dissertation focus on research conducted to characterize pipe bombs during and after an explosion (post-blast). Pipe bombs represent a large percentage of domestic devices encountered by law enforcement. The current project has involved the preparation and controlled explosion of over 90 pipe bombs of different configurations in order to obtain data on fragmentation patterns, fragment velocity, blast overpressure, and fragmentation distance. Physical data recorded from the collected fragments, such as mass, size, and thickness, was correlated with the relative power of the initial device. Manuscript 4 explores the microstructural analysis of select pipe bomb fragments. Shock-loading of the pipe steel led to plastic deformation and work hardening in the steel grain structure as evidenced by optical microscopy and

  20. Strain Rate Effects in CFRP Used For Blast Mitigation

    Directory of Open Access Journals (Sweden)

    Sarah. L. Orton

    2014-04-01

    Full Text Available The purpose of this research is to gain a better understanding of strain rate effects in carbon fiber reinforced polymer (CFRP laminates exposed to blast loading. The use of CFRP offers an attractive option for mitigating structures exposed to blasts. However, the effect of high strain rates in CFRP composites commonly used in the civil industry is unknown. This research conducted tensile tests of 21 CFRP coupons using a hydraulically powered dynamic loader. The strain rates ranged from 0.0015 s−1 to 7.86 s−1 and are representative of strain rates that CFRP may see in a blast when used to strengthen reinforced concrete structures. The results of the testing showed no increase in the tensile strength or stiffness of the CFRP at the higher strain rates. In addition, the results showed significant scatter in the tensile strengths possibly due to the rate of loading or manufacture of the coupon.

  1. MATHEMATICAL MODEL OF THE MOTION OF A LIGHT ATTACK AIRCRAFT WITH EXTERNAL LOAD SLINGS IN THE EXTREME AREA OF FLIGHT MODES ACCORDING TO THE ANGLE OF ATTACK

    Directory of Open Access Journals (Sweden)

    A. Popov Sergey

    2017-01-01

    Full Text Available For the time being, a combat-capable trainer aircraft has already been used as a light attack aircraft. The quality of mission effectiveness evaluation depends on the degree of relevance of mathematical models used. It is known that the mis- sion efficiency is largely determined by maneuvering capabilities of the aircraft which are realized most fully in extreme angle of attack flight modes. The article presents the study of the effect of Reynolds number, angle of attack and position on the external sling on the parameters characterizing the state of separated-vortex flow, which was conducted using soft- ware complexes such as Solid Works and Ansys Fluent. There given the dependences of the observed parameters for sta- tionary and nonstationary cases of light attack aircraft movement. The article considers the influence of time constants, which characterize the response rate and delaying of separated flow development and attached flow recovery on the state of separated-vortex flow. The author mentions how the speed of angle of attack change influences lift coefficient of a light attack aircraft with external slings due to response rate and delaying of separated flow development and attached flow recovery. The article describes the mathematical model invented by the authors. This is the model of the movements of light attack aircraft with external slings within a vertical flight maneuver, considering the peculiarities of separated-vortex flow. Using this model, there has been obtained the parameters of light attack aircraft output path from the pitch using large an- gles of attack. It is demonstrated that not considering the peculiarities of the separated-vortex flow model of light attack aircraft movements leads to certain increase of height loss at the pullout of the maneuver, which accordingly makes it pos- sible to decrease the height of the beginning of the pullout.

  2. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

    2004-01-01

    (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements...... are consistent, given the inevitabel uncertainties associated with model as well as with the extreme value data analysis. Keywords: Statistical model, extreme wind conditions, statistical analysis, turbulence, wind loading, statistical analysis, turbulence, wind loading, wind shear, wind turbines....

  3. Analysis of the Blasting Compaction on Gravel Soil

    Directory of Open Access Journals (Sweden)

    Qingwen Li

    2015-01-01

    Full Text Available The settlement control is critical for the safety of road based on high filled embankment. The traditional construction methods have the characteristic with less soil thickness compacted at a time. There are many advantages to compact the gravel soil with blasting. The cavity in soil is formed by blasting and its fillings to form a composite foundation for the embankment. The field data show this composite foundation can meet the requirement of loading and settlement control with less construction time. In geotechnical blasting, the high temperature due to blasting will swell the material around, so its worthy to do the coupled analysis with thermal mechanics (TM and blasting compaction in the high filled embankment. In this paper, a 3D model is built with FLAC3D to simulate a single hole to predict the range and degree of thermal propagation. Then, the thermal strains got from the model are used to estimate the displacement of surrounding soil to predict the degree of compaction and optimize the distribution of blast holes in plan.

  4. Significant head accelerations can influence immediate neurological impairments in a murine model of blast-induced traumatic brain injury.

    Science.gov (United States)

    Gullotti, David M; Beamer, Matthew; Panzer, Matthew B; Chen, Yung Chia; Patel, Tapan P; Yu, Allen; Jaumard, Nicolas; Winkelstein, Beth; Bass, Cameron R; Morrison, Barclay; Meaney, David F

    2014-09-01

    Although blast-induced traumatic brain injury (bTBI) is well recognized for its significance in the military population, the unique mechanisms of primary bTBI remain undefined. Animate models of primary bTBI are critical for determining these potentially unique mechanisms, but the biomechanical characteristics of many bTBI models are poorly understood. In this study, we examine some common shock tube configurations used to study blast-induced brain injury in the laboratory and define the optimal configuration to minimize the effect of torso overpressure and blast-induced head accelerations. Pressure transducers indicated that a customized animal holder successfully reduced peak torso overpressures to safe levels across all tested configurations. However, high speed video imaging acquired during the blast showed significant head accelerations occurred when animals were oriented perpendicular to the shock tube axis. These findings of complex head motions during blast are similar to previous reports [Goldstein et al., 2012, "Chronic Traumatic Encephalopathy in Blast-Exposed Military Veterans and a Blast Neurotrauma Mouse Model," Sci. Transl. Med., 4(134), 134ra160; Sundaramurthy et al., 2012, "Blast-Induced Biomechanical Loading of the Rat: An Experimental and Anatomically Accurate Computational Blast Injury Model," J. Neurotrauma, 29(13), pp. 2352-2364; Svetlov et al., 2010, "Morphologic and Biochemical Characterization of Brain Injury in a Model of Controlled Blast Overpressure Exposure," J. Trauma, 69(4), pp. 795-804]. Under the same blast input conditions, minimizing head acceleration led to a corresponding elimination of righting time deficits. However, we could still achieve righting time deficits under minimal acceleration conditions by significantly increasing the peak blast overpressure. Together, these data show the importance of characterizing the effect of blast overpressure on head kinematics, with the goal of producing models focused on understanding the

  5. Blast Testing Issues and TBI: Experimental Models That Lead to Wrong Conclusions.

    Science.gov (United States)

    Needham, Charles E; Ritzel, David; Rule, Gregory T; Wiri, Suthee; Young, Leanne

    2015-01-01

    Over the past several years, we have noticed an increase in the number of blast injury studies published in peer-reviewed biomedical journals that have utilized improperly conceived experiments. Data from these studies will lead to false conclusions and more confusion than advancement in the understanding of blast injury, particularly blast neurotrauma. Computational methods to properly characterize the blast environment have been available for decades. These methods, combined with a basic understanding of blast wave phenomena, enable researchers to extract useful information from well-documented experiments. This basic understanding must include the differences and interrelationships of static pressure, dynamic pressure, reflected pressure, and total or stagnation pressure in transient shockwave flows, how they relate to loading of objects, and how they are properly measured. However, it is critical that the research community effectively overcomes the confusion that has been compounded by a misunderstanding of the differences between the loading produced by a free field explosive blast and loading produced by a conventional shock tube. The principles of blast scaling have been well established for decades and when properly applied will do much to repair these problems. This paper provides guidance regarding proper experimental methods and offers insights into the implications of improperly designed and executed tests. Through application of computational methods, useful data can be extracted from well-documented historical tests, and future work can be conducted in a way to maximize the effectiveness and use of valuable biological test data.

  6. Blast Testing Issues and TBI; Experimental Models that Lead to Wrong Conclusions

    Directory of Open Access Journals (Sweden)

    Charles E. Needham

    2015-04-01

    Full Text Available Over the past several years we have noticed an increase in the number of blast injury studies published in peer-reviewed biomedical journals that have utilized improperly conceived experiments. Data from these studies will lead to false conclusions and more confusion than advancement in the understanding of blast injury, particularly blast neurotrauma. Computational methods to properly characterize the blast environment have been available for decades. These methods, combined with a basic understanding of blast wave phenomena enable researchers to extract useful information from well documented experiments. This basic understanding must include the differences and interrelationships of static pressure, dynamic pressure, reflected pressure, and total or stagnation pressure in transient shockwave flows, how they relate to loading of objects, and how they are properly measured. However, it is critical that the research community effectively overcomes the confusion that has been compounded by a misunderstanding of the differences between the loading produced by a free field explosive blast and loading produced by a conventional shock tube. The principles of blast scaling have been well established for decades and when properly applied will do much to repair these problems.This paper provides guidance regarding proper experimental methods and offers insights into the implications of improperly designed and executed tests. Through application of computational methods, useful data can be extracted from well documented historical tests, and future work can be conducted in a way to maximize the effectiveness and use of valuable biological test data.

  7. Explosively-Driven Blast Waves in Small-Diameter Tubes

    Science.gov (United States)

    Cooper, M. A.; Marinis, R. T.; Oliver, M. S.

    Studies on blast waves are motivated by the need to understand dynamic pressure loadings in accident scenarios associated with rapid energy release in confined geometries. Explosions from fuel-air mixtures, explosives and industrial accidents often occur within a range of length scales associated with ducts, pipes, corridors, and tunnels [1, 2].

  8. Modelling Blast Effects on a Reinforced Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Markellos Andreou

    2016-01-01

    Full Text Available The detailed investigation of blast phenomena and their catastrophic effects on existing structures are the main objectives of the present paper. It is well known that blast phenomena may be characterized by significant complexity, often involving complicated wave propagation effects as well as distinguishable material behaviors. Considering the above and in an attempt to provide a simplified modelling approach for the simulation of blast effects, a novel procedure is presented herein based on well-established methodologies and common engineering practices. In the above framework, firstly, the “predominant” deformation shape of the structure is estimated based on elastic finite element simulations under blast loads and then the structural response of the system is evaluated as a result of common computational beam-element tools such as displacement-based pushover analysis. The proposed methodology provides an immediate first estimation of the structural behavior under blast loads, based on familiar engineering procedures. A two-span reinforced concrete bridge was thoroughly investigated and the results provide insightful information regarding the damage patterns and localization.

  9. Brittle materials at high-loading rates: an open area of research

    Science.gov (United States)

    Forquin, Pascal

    2017-01-01

    Brittle materials are extensively used in many civil and military applications involving high-strain-rate loadings such as: blasting or percussive drilling of rocks, ballistic impact against ceramic armour or transparent windshields, plastic explosives used to damage or destroy concrete structures, soft or hard impacts against concrete structures and so on. With all of these applications, brittle materials are subjected to intense loadings characterized by medium to extremely high strain rates (few tens to several tens of thousands per second) leading to extreme and/or specific damage modes such as multiple fragmentation, dynamic cracking, pore collapse, shearing, mode II fracturing and/or microplasticity mechanisms in the material. Additionally, brittle materials exhibit complex features such as a strong strain-rate sensitivity and confining pressure sensitivity that justify expending greater research efforts to understand these complex features. Currently, the most popular dynamic testing techniques used for this are based on the use of split Hopkinson pressure bar methodologies and/or plate-impact testing methods. However, these methods do have some critical limitations and drawbacks when used to investigate the behaviour of brittle materials at high loading rates. The present theme issue of Philosophical Transactions A provides an overview of the latest experimental methods and numerical tools that are currently being developed to investigate the behaviour of brittle materials at high loading rates. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  10. PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE

    Directory of Open Access Journals (Sweden)

    CHANG-SU SHIM

    2013-06-01

    Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.

  11. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan

    2011-01-01

    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  12. Blasting Damage Predictions by Numerical Modeling in Siahbishe Pumped Storage Powerhouse

    Science.gov (United States)

    Eslami, Majid; Goshtasbi, Kamran

    2017-04-01

    One of the popular methods of underground and surface excavations is the use of blasting. Throughout this method of excavation, the loading resulted from blasting can be affected by different geo-mechanical and structural parameters of rock mass. Several factors affect turbulence in underground structures some of which are explosion, vibration, and stress impulses caused by the neighbouring blasting products. In investigating the blasting mechanism one should address the processes which expand with time and cause seismic events. To protect the adjoining structures against any probable deconstruction or damage, it is very important to model the blasting process prior to any actual operation. Efforts have been taken in the present study to demonstrate the potentiality of numerical methods in predicting the specified parameters in order to prevent any probable destruction. For this purpose the blasting process was modeled, according to its natural implementation, in one of the tunnels of Siahbishe dam by the 3DEC and AUTODYN 3D codes. 3DEC was used for modeling the blasting environment as well as the blast holes and AUTODYN 3D for modeling the explosion process in the blast hole. In this process the output of AUTODYN 3D, which is a result of modeling the blast hole and is in the form of stress waves, is entered into 3DEC. For analyzing the amount of destruction made by the blasting operation, the key parameter of Peak Particle Velocity was used. In the end, the numerical modeling results have been compared with the data recorded by the seismographs planted through the tunnel. As the results indicated 3DEC and AUTODYN 3D proved appropriate for analyzing such an issue. Therefore, by means of these two softwares one can analyze explosion processes prior to their implementation and make close estimation of the damage resulting from these processes.

  13. Assessment, development, and testing of glass for blast environments.

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Sarah Jill

    2003-06-01

    Glass can have lethal effects including fatalities and injuries when it breaks and then flies through the air under blast loading (''the glass problem''). One goal of this program was to assess the glass problem and solutions being pursued to mitigate it. One solution to the problem is the development of new glass technology that allows the strength and fragmentation to be controlled or selected depending on the blast performance specifications. For example the glass could be weak and fail, or it could be strong and survive, but it must perform reliably. Also, once it fails it should produce fragments of a controlled size. Under certain circumstances it may be beneficial to have very small fragments, in others it may be beneficial to have large fragments that stay together. The second goal of this program was to evaluate the performance (strength, reliability, and fragmentation) of Engineered Stress Profile (ESP) glass under different loading conditions. These included pseudo-static strength and pressure tests and free-field blast tests. The ultimate goal was to provide engineers and architects with a glass whose behavior under blast loading is less lethal. A near-term benefit is a new approach for improving the reliability of glass and modifying its fracture behavior.

  14. Wind Simulation for Extreme and Fatigue Loads

    DEFF Research Database (Denmark)

    Nielsen, Morten; Larsen, Gunner Chr.; Mann, Jakob

    2003-01-01

    by many orders of magnitude, mainly because the measured pdf is non-Gaussian. Methods for simulation of turbulent signals have been developed and theircomputational efficiency are considered. The methods are applicable for multiple processes with individual spectra and probability distributions. Non......Measurements of atmospheric turbulence have been studied and found to deviate from a Gaussian process, in particular regarding the velocity increments over small time steps, where the tails of the pdf are exponential rather than Gaussian. Principles forextreme event counting and the occurrence...... is formulated as the variational problem of finding the most probable adjustment of a standard simulation of a stationary Gaussian process subject to relevant event conditions, which are formulated as linear combination of pointsin the realization. The method is generalized for multiple correlated series...

  15. Dynamic Fracture of Nanocomposites and Response of Fiber Composite Panels to Shock Loading

    Science.gov (United States)

    Shukla, Arun

    2009-06-01

    This lecture will present studies on the response of novel engineering materials to extreme dynamic loadings. In particular, the talk will focus on the behavior of sandwich composite materials to shock loading and dynamic fracture of nano-composite materials. Results from an experimental study on the response of sandwich materials to controlled blast loading will be presented. In this study, a shock tube facility was utilized to apply blast loading to simply supported plates of E-glass vinyl ester/PVC foam sandwich composite materials. Pressure sensors were mounted at the end of the muzzle section of the shock tube to measure the incident pressure and the reflected pressure profiles during the experiment. A high speed digital camera was utilized to capture the real time side deformation of the materials, as well as the development and progression of damage. Macroscopic and microscopic examination was then implemented to study the post-mortem damage. Conclusions on the relative performance of sandwich composites under blast loadings will also be discussed. Results from an experimental investigation conducted to evaluate the mechanical properties of novel materials fabricated using nano sized particles in polymer matrix will also be presented. Unsaturated polyester resin specimens embedded with small loadings of nano sized particles of TiO2 and Al2O3 were fabricated using a direct ultrasonification method to study the effects of nanosized particles on nanocomposite fracture properties. The ultrasonification method employed produced nanocomposites with excellent particle dispersion as verified by TEM. Experiments were conducted to investigate the dynamic crack initiation and rapid crack propagation in theses particle reinforced materials. High-speed digital imaging was employed along with dynamic photoelasticity to obtain real time, full-field quantification of the stress field associated with the dynamic fracture process. Birefringent coatings were used to conduct

  16. Microcavitation as a neuronal damage mechanism in blast -traumatic brain injury

    OpenAIRE

    Estrada, Jon; Franck, Christian

    2014-01-01

    Traumatic brain injury (TBI), usually the result of impact or blast to the head, affects about 1.5 million Americans annually. Diffuse axonal injury, the hallmark feature of blunt TBI, has been investigated in direct mechanical loading conditions. However, recent evidence suggests inertial cavitation as a possible bTBI mechanism, particularly in the case of armed forces exposed to concussive blasts. Cavitation damage to free surfaces has been well-studied in the field of fluid dynamics, but b...

  17. Computational modeling of blast exposure associated with recoilless weapons combat training

    Science.gov (United States)

    Wiri, S.; Ritter, A. C.; Bailie, J. M.; Needham, C.; Duckworth, J. L.

    2017-11-01

    Military personnel are exposed to blast as part of routine combat training with shoulder-fired recoilless rifles. These weapons fire large-caliber ammunitions capable of disabling structures and uparmored vehicles (e.g., tanks). Scientific, medical, and military leaders are beginning to recognize the blast overpressure from these shoulder-fired weapons may result in acute and even long-term physiological effects to military personnel. However, the back blast generated from the Carl Gustav and Shoulder-launched Multipurpose Assault Weapon (SMAW) shoulder-fired weapons on the weapon operator has not been quantified. By quantifying and modeling the full-body blast exposure from these weapons, better injury correlations can be constructed. Blast exposure data from the Carl Gustav and SMAW were used to calibrate a propellant burn source term for computational simulations of blast exposure on operators of these shoulder-mounted weapon systems. A propellant burn model provided the source term for each weapon to capture blast effects. Blast data from personnel-mounted gauges during weapon firing were used to create initial, high-fidelity 3D computational fluid dynamic simulations using SHAMRC (Second-order Hydrodynamic Automatic Mesh Refinement Code). These models were then improved upon using data collected from static blast sensors positioned around the military personnel while weapons were utilized in actual combat training. The final simulation models for both the Carl Gustav and SMAW were in good agreement with the data collected from the personnel-mounted and static pressure gauges. Using the final simulation results, contour maps were created for peak overpressure and peak overpressure impulse experienced by military personnel firing the weapon as well as those assisting with firing of those weapons. Reconstruction of the full-body blast loading enables a more accurate assessment of the cause of potential mechanisms of injury due to air blast even for subjects not

  18. Computational modeling of blast exposure associated with recoilless weapons combat training

    Science.gov (United States)

    Wiri, S.; Ritter, A. C.; Bailie, J. M.; Needham, C.; Duckworth, J. L.

    2017-09-01

    Military personnel are exposed to blast as part of routine combat training with shoulder-fired recoilless rifles. These weapons fire large-caliber ammunitions capable of disabling structures and uparmored vehicles (e.g., tanks). Scientific, medical, and military leaders are beginning to recognize the blast overpressure from these shoulder-fired weapons may result in acute and even long-term physiological effects to military personnel. However, the back blast generated from the Carl Gustav and Shoulder-launched Multipurpose Assault Weapon (SMAW) shoulder-fired weapons on the weapon operator has not been quantified. By quantifying and modeling the full-body blast exposure from these weapons, better injury correlations can be constructed. Blast exposure data from the Carl Gustav and SMAW were used to calibrate a propellant burn source term for computational simulations of blast exposure on operators of these shoulder-mounted weapon systems. A propellant burn model provided the source term for each weapon to capture blast effects. Blast data from personnel-mounted gauges during weapon firing were used to create initial, high-fidelity 3D computational fluid dynamic simulations using SHAMRC (Second-order Hydrodynamic Automatic Mesh Refinement Code). These models were then improved upon using data collected from static blast sensors positioned around the military personnel while weapons were utilized in actual combat training. The final simulation models for both the Carl Gustav and SMAW were in good agreement with the data collected from the personnel-mounted and static pressure gauges. Using the final simulation results, contour maps were created for peak overpressure and peak overpressure impulse experienced by military personnel firing the weapon as well as those assisting with firing of those weapons. Reconstruction of the full-body blast loading enables a more accurate assessment of the cause of potential mechanisms of injury due to air blast even for subjects not

  19. Blast impact behaviour of concrete with different fibre reinforcement

    Science.gov (United States)

    Drdlová, Martina; Čechmánek, René; Řídký, Radek

    2015-09-01

    The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer) of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concrete prism specimens have been subjected to the determination of mechanical parameters (compressive and flexural strength at quasi-static load). The blast tests were conducted on the slab specimens prepared from selected mixtures. The material characteristics and explosion test data have been used for numerical investigation, which defined the optimal wall composition and dimensions of the concrete element which should resist the explosion defined by type, size, weight and placement of the blast. In the next step the test elements resistance was verified by real explosion test.

  20. Micro-blast waves using detonation transmission tubing

    Science.gov (United States)

    Samuelraj, I. Obed; Jagadeesh, G.; Kontis, K.

    2013-07-01

    Micro-blast waves emerging from the open end of a detonation transmission tube were experimentally visualized in this study. A commercially available detonation transmission tube was used (Nonel tube, M/s Dyno Nobel, Sweden), which is a small diameter tube coated with a thin layer of explosive mixture (HMX + traces of Al) on its inner side. The typical explosive loading for this tube is of the order of 18 mg/m of tube length. The blast wave was visualized using a high speed digital camera (frame rate 1 MHz) to acquire time-resolved schlieren images of the resulting flow field. The visualization studies were complemented by computational fluid dynamic simulations. An analysis of the schlieren images showed that although the blast wave appears to be spherical, it propagates faster along the tube axis than along a direction perpendicular to the tube axis. Additionally, CFD analysis revealed the presence of a barrel shock and Mach disc, showing structures that are typical of an underexpanded jet. A theory in use for centered large-scale explosions of intermediate strength (10 blast trajectory along the tube axis. The energy of these micro-blast waves was found to be 1.25 ± 0.94 J and the average TNT equivalent was found to be 0.3. The repeatability in generating these micro-blast waves using the Nonel tube was very good (± 2 %) and this opens up the possibility of using this device for studying some of the phenomena associated with muzzle blasts in the near future.

  1. Computational modeling of blast wave interaction with a human body and assessment of traumatic brain injury

    Science.gov (United States)

    Tan, X. G.; Przekwas, A. J.; Gupta, R. K.

    2017-07-01

    The modeling of human body biomechanics resulting from blast exposure poses great challenges because of the complex geometry and the substantial material heterogeneity. We developed a detailed human body finite element model representing both the geometry and the materials realistically. The model includes the detailed head (face, skull, brain and spinal cord), the neck, the skeleton, air cavities (lungs) and the tissues. Hence, it can be used to properly model the stress wave propagation in the human body subjected to blast loading. The blast loading on the human was generated from a simulated C4 explosion. We used the highly scalable solvers in the multi-physics code CoBi for both the blast simulation and the human body biomechanics. The meshes generated for these simulations are of good quality so that relatively large time-step sizes can be used without resorting to artificial time scaling treatments. The coupled gas dynamics and biomechanics solutions were validated against the shock tube test data. The human body models were used to conduct parametric simulations to find the biomechanical response and the brain injury mechanism due to blasts impacting the human body. Under the same blast loading condition, we showed the importance of inclusion of the whole body.

  2. Computational modeling of blast wave interaction with a human body and assessment of traumatic brain injury

    Science.gov (United States)

    Tan, X. G.; Przekwas, A. J.; Gupta, R. K.

    2017-11-01

    The modeling of human body biomechanics resulting from blast exposure poses great challenges because of the complex geometry and the substantial material heterogeneity. We developed a detailed human body finite element model representing both the geometry and the materials realistically. The model includes the detailed head (face, skull, brain and spinal cord), the neck, the skeleton, air cavities (lungs) and the tissues. Hence, it can be used to properly model the stress wave propagation in the human body subjected to blast loading. The blast loading on the human was generated from a simulated C4 explosion. We used the highly scalable solvers in the multi-physics code CoBi for both the blast simulation and the human body biomechanics. The meshes generated for these simulations are of good quality so that relatively large time-step sizes can be used without resorting to artificial time scaling treatments. The coupled gas dynamics and biomechanics solutions were validated against the shock tube test data. The human body models were used to conduct parametric simulations to find the biomechanical response and the brain injury mechanism due to blasts impacting the human body. Under the same blast loading condition, we showed the importance of inclusion of the whole body.

  3. Development of in-house high-resolution hydrocode for assessment of blast waves and its application

    Directory of Open Access Journals (Sweden)

    XU Weizheng

    2017-05-01

    Full Text Available The propagation and evolution characteristics of blast waves in confined spaces are complicated due to the constraint of the surrounding walls, by which the enhanced reflected shock waves will cause more serious damage to the internal structures, facilities and personnel. In order to investigate the characteristics of explosions in confined spaces, an in-house high-resolution hydrocode was developed in this present work. The third-order WENO finite difference scheme (weighted essentially non-oscillation scheme was implemented in the code to capture the shock waves generated by cylindrical explosives. The Sod shock tube problem, interacting blast wave problem and blast in air problem were simulated to validate the code. The validated code was then used to simulate the blast waves generated by condensed explosives in closed, vented and connected spaces. The propagation of blast waves and the characteristics of blast load were subsequently investigated. The developed code appears to accurately predict the process of explosions in confined spaces. This high-resolution hydrocode can be used to study the propagation paths of blast waves in complicated spaces and evaluate the internal blast load, which can provide reliable input for the design of explosion-resistant structures.

  4. Immediate functional loading of single-tooth TiO2 grit-blasted implant restoration. A controlled prospective study in a porcine model. Part II: Histology and histomorphometry.

    NARCIS (Netherlands)

    Bousdras, V.A.; Walboomers, F.; Jansen, J.A.; Cunningham, J.L.; Blunn, G.; Petrie, A.; Jaecques, S.V.; Naert, I.E.; Sindet-Pedersen, S.; Goodship, A.E.

    2007-01-01

    BACKGROUND: Evidently, there is a fast-moving shift from delayed to immediate implant loading. The hypothesis to be tested was that bone reactions adjacent to single TiO2-microthreaded implants exposed to immediate masticatory loading for 10 weeks after placement would modulate osseointegration.

  5. The effects of a strength and neuromuscular exercise programme for the lower extremity on knee load, pain and function in obese children and adolescents: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Horsak, Brian; Artner, David; Baca, Arnold; Pobatschnig, Barbara; Greber-Platzer, Susanne; Nehrer, Stefan; Wondrasch, Barbara

    2015-12-23

    Childhood obesity is one of the most critical and accelerating health challenges throughout the world. It is a major risk factor for developing varus/valgus misalignments of the knee joint. The combination of misalignment at the knee and excess body mass may result in increased joint stresses and damage to articular cartilage. A training programme, which aims at developing a more neutral alignment of the trunk and lower limbs during movement tasks may be able to reduce knee loading during locomotion. Despite the large number of guidelines for muscle strength training and neuromuscular exercises that exist, most are not specifically designed to target the obese children and adolescent demographic. Therefore, the aim of this study is to evaluate a training programme which combines strength and neuromuscular exercises specifically designed to the needs and limitations of obese children and adolescents and analyse the effects of the training programme from a biomechanical and clinical point of view. A single assessor-blinded, pre-test and post-test randomised controlled trial, with one control and one intervention group will be conducted with 48 boys and girls aged between 10 and 18 years. Intervention group participants will receive a 12-week neuromuscular and quadriceps/hip strength training programme. Three-dimensional (3D) gait analyses during level walking and stair climbing will be performed at baseline and follow-up sessions. The primary outcome parameters for this study will be the overall peak external frontal knee moment and impulse during walking. Secondary outcomes include the subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS), frontal and sagittal kinematics and kinetics for the lower extremities during walking and stair climbing, ratings of change in knee-related well-being, pain and function and adherence to the training programme. In addition, the training programme will be evaulated from a clinical and health status perspective by

  6. Evaluation of the Mangled Extremity Severity Score in Combat-Related Type III Tibia Fracture

    Science.gov (United States)

    2014-09-01

    records were then queried from the Patient Administration Systems and Biostatistics Activity (PASBA) using Web Accepted for publication December 13...Extremities (%) Amputated Extremities (%) Blast 130 (84) 95 (73) 35 (27) GSW 13 (8) 13 (100) 0 (0) MVC 8 (5) 4 (50) 4 (50) Other 5 (3) 4 (80) 1 (20) Sheean et

  7. Case Study on Influence of Step Blast-Excavation on Support Systems of Existing Service Tunnel with Small Interval

    Directory of Open Access Journals (Sweden)

    Shaorui Sun

    2013-01-01

    Full Text Available During the construction of newly built tunnel (NBT adjacent to the existing service tunnel (EST, stability of the EST with small interval is affected by vibration waves which are caused by blasting load. The support structures of the EST will be cracked and damaged, while the unreasonable blast-excavation methods are adopted. Presently, the studies on behavior of support structure in the EST under blasting load are not totally clear, especially for the bolts system. Besides, the responses of support structure on blasting load are lacking comprehensive research. In this paper, New Zuofang tunnel is taken as a study case to study the influence of step blast-excavation in NBT on support structures of the EST through field experiment and numerical simulation. Some data, such as blasting vibration velocity (BVV and frequency of support structures, are obtained through field measurement. Based on these data, the formula of BVVs is obtained. Research on stability of tunnel support structures affected by step blast-excavation is conducted using numerical simulation method. The dynamic-plastic constitutive model is adopted in the software ABAQUS to assess safety of support structures. The range and degree of damage for the support structures are obtained. In addition, change laws of axial force and stress with time for the bolts are analyzed.

  8. Blast energy mitigation in porous rocks

    Science.gov (United States)

    Essink, Brittany C.

    Geo-materials are commonly used and sought after for blast mitigation applications due to their wide availability and low cost compared to industry trademarked materials. Characterization of these natural geo-materials such as volcanic rocks is of paramount importance in determining their blast mitigation capabilities. While there is a large amount of information available for materials such as concrete or sand blasts, information on the properties of volcanic rocks is far more scarce. This lack of data is due to the wide range of existing natural volcanic rocks and the variation in the minerals and pore structures of the rocks. In this thesis, silicate volcanic rock samples are characterized both through static and dynamic experimental methods. Initial X-ray powder diffraction scans have been conducted and analyzed to obtain the mineral composition information of the rock samples. Additional tomographic scans under quasi-static loading have been recorded to better understand the internal composition of the material pore structure and the material fracture. For this study, standard compression experiments were conducted at two separate strain rates for ten samples each on a UTM test frame to characterize the behavior of the rock under quasi-static conditions. High strain rate uniaxial compression tests were conducted for three strain rates using a split-Hopkinson pressure bar with pulse shaping to determine the dynamic response of the material. The stress-strain data from the experiments was used to determine the modulus of toughness of the material. Due to the high porosity and heterogeneity of the material, 25 samples were used for dynamic experimentation to attempt to capture and minimize the effects of scatter in the natural material. High speed photography was used to capture the sample deformation during two separate strain rates and to visualize crack propagation and strain rate in the samples. It was found that after an initial yielding, the material is

  9. CONTROL OF FRAGMENTATION BY BLASTING

    Directory of Open Access Journals (Sweden)

    Branko Božić

    1998-12-01

    Full Text Available The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the quantity of explosive and its distribution within the rock mass. Over the last decade there have been considerable advances in our ability to measure and analyze blasting performance. These can now be combined with the continuing growth in computing power to develop a more effective description of rock fragmentation for use by future blasting practitioners. The paper describes a view of the fragmentation problem by blasting and the need for a new generation of engineering tools to guide the design and implementation of blasting operations.

  10. Blasting agents and initiation systems

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2000-01-01

    Although blasting differs between and within each industry, as a whole, the mines and quarries are making a shift from a purely ammonium nitrate/fuel oil (ANFO) mixture to a blend of emulsion and ANFO on a straight emulsion. Non-electric (shock tube) initiation systems have provided a viable alternative to the electric detonator (blasting cap). Explosives manufacturers are seeing their roles changes to being blasting contractors or consultants rather than just suppliers. The article discusses these trends and gives examples of typical blasting techniques and amounts of blasting agent used at large USA surface coal mines. Electric caps are still used in blasting underground coal. The Ensign Bickford Co. (EBCo) is developing electronic detonators and has been field testing an electronic initiator, the DIGIDET detonator, for the last four years. When commercially available, electronic detonators will be accurate but will come with a hefty price tag. 2 photos.

  11. Simulation analysis of effects of single fragment size on air-blast wave and fragment propagation

    Directory of Open Access Journals (Sweden)

    ZHENG Hongwei

    2017-12-01

    Full Text Available [Objectives] This paper involves the propagation and attenuation of the velocity and energy of air-blast waves and high-velocity fragments while taking their combined effects into account.[Methods] With ANSYS/LS-DYNA software, a simulation model of a columnar TNT air blast is built with prefabricated fragments affixed to its end. When the total quality of fragments is constant, the effects of a single fragment's size on the propagation of the air-blast wave and fragments are studied by changing the size of the single fragment.[Results] The results show that fragments greatly reduce the intensity and velocity of a shockwave, and block the air-blast waves behind them. When the total quality of the fragments remains constant, the effects of single fragment size on blast shockwave propagation characteristics show little difference. The smaller the single fragment, the more kinetic energy the fragments will have and the faster that energy will dissipate.[Conclusions] As a result, more attention should be paid to the combined effects of air-blast waves and high-velocity fragments. Such research can provide reference points for the deeper study of blast loads and their interaction.

  12. The BLAST experiment

    NARCIS (Netherlands)

    Hasell, D.; Botto, T.; van den Brand, J.F.J.

    2009-01-01

    The Bates large acceptance spectrometer toroid (BLAST) experiment was operated at the MIT-Bates Linear Accelerator Center from 2003 until 2005. The detector and experimental program were designed to study, in a systematic manner, the spin-dependent electromagnetic interaction in few-nucleon systems.

  13. NCBI BLAST+ integrated into Galaxy

    OpenAIRE

    Cock, Peter J.A.; John M. Chilton; Gr?ning, Bj?rn; James E. Johnson; Soranzo, Nicola

    2015-01-01

    Background The NCBI BLAST suite has become ubiquitous in modern molecular biology and is used for small tasks such as checking capillary sequencing results of single PCR products, genome annotation or even larger scale pan-genome analyses. For early adopters of the Galaxy web-based biomedical data analysis platform, integrating BLAST into Galaxy was a natural step for sequence comparison workflows. Findings The command line NCBI BLAST+ tool suite was wrapped for use within Galaxy. Appropriate...

  14. PREVALENCE OF RICE BLAST AND VARIETAL

    African Journals Online (AJOL)

    search-screening site grown to an improved vari- ety, Tox 3050, was heavily blasted. There was no blast incidence at Damongo. in Upper East. Region, there was severe incidence of blast in farmers' fields at Bawku and PVS nurseries and farmers' fields at Nyorigu. There was no blast at. Manga, Navrongo, Tono, Sandema, ...

  15. CrocoBLAST: Running BLAST efficiently in the age of next-generation sequencing.

    Science.gov (United States)

    Tristão Ramos, Ravi José; de Azevedo Martins, Allan Cézar; da Silva Delgado, Gabrielle; Ionescu, Crina-Maria; Ürményi, Turán Peter; Silva, Rosane; Koca, Jaroslav

    2017-11-15

    CrocoBLAST is a tool for dramatically speeding up BLAST+ execution on any computer. Alignments that would take days or weeks with NCBI BLAST+ can be run overnight with CrocoBLAST. Additionally, CrocoBLAST provides features critical for NGS data analysis, including: results identical to those of BLAST+; compatibility with any BLAST+ version; real-time information regarding calculation progress and remaining run time; access to partial alignment results; queueing, pausing, and resuming BLAST+ calculations without information loss. CrocoBLAST is freely available online, with ample documentation (webchem.ncbr.muni.cz/Platform/App/CrocoBLAST). No installation or user registration is required. CrocoBLAST is implemented in C, while the graphical user interface is implemented in Java. CrocoBLAST is supported under Linux and Windows, and can be run under Mac OS X in a Linux virtual machine. jkoca@ceitec.cz. Supplementary data are available at Bioinformatics online.

  16. Pulmonary blast injury in mice: a novel model for studying blast injury in the laboratory using laser-induced stress waves.

    Science.gov (United States)

    Satoh, Yasushi; Sato, Shunichi; Saitoh, Daizoh; Tokuno, Shinichi; Hatano, Ben; Shimokawaji, Tadasuke; Kobayashi, Hideo; Takishima, Kunio

    2010-04-01

    Primary blast injury is produced by shock waves. Blast injuries to lungs are extremely critical threats to survival, but their etiology is largely undefined. The majority of animal models for these injuries use explosive or complex experimental settings, limiting the laboratory study of blast injury. The aim of this study was to establish a small-animal model for blast injuries, using laser-induced stress waves (LISWs) with high controllability, high reproducibility, and easy experimental settings. LISWs were used to produce isolated pulmonary blast effects in mice. An LISW was generated by the irradiation of an elastic laser target with 532-nm nanosecond laser pulses of a Q-switched Nd:YAG laser. Histopathological evaluations of damage to lung tissue were conducted to estimate the relevance between peak pressure and trauma intensity. Blood pressure, heart rate, and percutaneous oxygen saturation were monitored for 60 minutes. We could flexibly control the peak pressure of the shock wave by varying the laser energy. Non-lethal doses of LISWs caused pulmonary contusions with alveolar hemorrhages depending on peak pressure. Pulmonary contusion was observed only in areas that were exposed to LISWs, allowing study of isolated injuries without concomitant ones. These injuries caused decreased blood pressure, heart rate, and percutaneous oxygen saturation, immediately after LISW exposure. Mice exposed to thoracic LISWs showed pathologic and physiologic changes similar to those seen in other studies in this area, and in clinical practice. Our newly developed model allows fine management of trauma intensity, and concomitant injuries of the exposed animals were limited. This novel mouse model of blast injury using LISWs is suitable for detailed studies of blast lung contusion and other blast injuries in the laboratory. (c) 2010 Wiley-Liss, Inc.

  17. BOMB BLAST: PATTERN AND NATURE OF INJURIES

    OpenAIRE

    Brahmaji Master; Chandra Sekhar; Rangaiah

    2015-01-01

    Bomb blast cause injury on large groups of people by multiple mechanisms. Bomb blast injuries differ from the conventional description of trauma complexity. Primary injuries are caused by blast wave and over pressure. Secondary injuries are caused by flyin g debris and cause shrapnel wounds. Tertiary injuries are caused by blast wind due to forceful impact and quaternary injuries are caused by other vectors like heat, radiation etc. Combined injuries, especially blast and...

  18. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.

    2005-01-01

    (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describes the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of full-scale measurements recorded with a high sampling rate......In order to continue cost-optimisation of modern large wind turbines, it is important to continuously increase the knowledge of wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...

  19. Tympanoplasty following Blast Injury.

    Science.gov (United States)

    Keller, Matthew; Sload, Ryan; Wilson, Justin; Greene, Howard; Han, Peggy; Wise, Sean

    2017-12-01

    Objectives To assess outcomes following tympanoplasty for blast-induced tympanic membrane perforations in a military population. Study Design Case series with chart review. Setting Tertiary care medical centers. Subjects and Methods Military personnel (N = 254) undergoing tympanoplasty for blast-related tympanic membrane perforations sustained between April 2005 and July 2014 were identified from the Expeditionary Medical Encounter Database. Descriptive statistics were obtained regarding demographics, primary and revision surgery success rates, hearing status pre- and postsurgery, and frequency of ossicular reconstruction. Rates of successful perforation closure were assessed against perforation size and character (central vs marginal) and time to surgery. Rates and types of complications were additionally explored. Results There were a total of 352 operations among 254 subjects, with an 82.1% rate of successful closure following primary surgery. For successful primary tympanoplasty, the mean improvement in pure tone average was 11.7 ± 12.1 dB. Ossiculoplasty was performed in 9.1% (32 of 352) of cases. There was no significant relationship between successful perforation closure and perforation size, perforation character, or time between injury and surgery. Cholesteatoma complicated 4.3% (15 of 352) of cases. A significant relationship was identified between risk of cholesteatoma development and increasing perforation size and marginal perforations. Conclusion Tympanoplasty success rates for blast-induced tympanic membrane perforations are lower than for other common injury mechanisms. Due to appreciable rates of postoperative cholesteatoma development, close clinical surveillance is recommended.

  20. Modelling of blast-induced damage in tunnels using a hybrid finite-discrete numerical approach

    Directory of Open Access Journals (Sweden)

    Amichai Mitelman

    2014-12-01

    Full Text Available This paper presents the application of a hybrid finite-discrete element method to study blast-induced damage in circular tunnels. An extensive database of field tests of underground explosions above tunnels is used for calibrating and validating the proposed numerical method; the numerical results are shown to be in good agreement with published data for large-scale physical experiments. The method is then used to investigate the influence of rock strength properties on tunnel durability to withstand blast loads. The presented analysis considers blast damage in tunnels excavated through relatively weak (sandstone and strong (granite rock materials. It was found that higher rock strength will increase the tunnel resistance to the load on one hand, but decrease attenuation on the other hand. Thus, under certain conditions, results for weak and strong rock masses are similar.

  1. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    William S. McPhee

    1999-05-31

    The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and

  2. Protecting the lower extremity against a/p blast mines

    CSIR Research Space (South Africa)

    van Dyk, T

    2006-09-01

    Full Text Available stream_source_info Van Dyk1_2006.pdf.txt stream_content_type text/plain stream_size 4287 Content-Encoding UTF-8 stream_name Van Dyk1_2006.pdf.txt Content-Type text/plain; charset=UTF-8 IBBTC-25-28 Sept 06 Protecting...

  3. Load research and load estimation in electricity distribution

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland). Energy Systems

    1996-12-31

    The topics introduced in this thesis are: the Finnish load research project, a simple form customer class load model, analysis of the origins of customers load distribution, a method for the estimation of the confidence interval of customer loads and Distribution Load Estimation (DLE) which utilises both the load models and measurements from distribution networks. The Finnish load research project started in 1983. The project was initially coordinated by the Association of Finnish Electric Utilities and 40 utilities joined the project. Now there are over 1000 customer hourly load recordings in a database. A simple form customer class load model is introduced. The model is designed to be practical for most utility applications and has been used by the Finnish utilities for several years. The only variable of the model is the customers annual energy consumption. The model gives the customers average hourly load and standard deviation for a selected month, day and hour. The statistical distribution of customer loads is studied and a model for customer electric load variation is developed. The model results in a lognormal distribution as an extreme case. Using the `simple form load model`, a method for estimating confidence intervals (confidence limits) of customer hourly load is developed. The two methods selected for final analysis are based on normal and lognormal distribution estimated in a simplified manner. The estimation of several cumulated customer class loads is also analysed. Customer class load estimation which combines the information from load models and distribution network load measurements is developed. This method, called Distribution Load Estimation (DLE), utilises information already available in the utilities databases and is thus easy to apply

  4. Subjects for achievement of blast furnace operation with low reducing agent rate

    Energy Technology Data Exchange (ETDEWEB)

    Ujisawa, Y.; Nakano, K.; Matsukura, Y.; Sunahara, K.; Komatsu, S.; Yamamoto, T. [Sumitomo Metal Industry Ltd., Kashima (Japan). Corp R& amp; D Labs.

    2006-12-15

    The technology which reduces the reducing agent rate by the improvement in the reaction efficiency of blast furnace leads to reduction of hot metal manufacturing cost, but also solution of recent CO{sub 2} emission reduction. The subjects for achievement of the blast furnace operation with low reducing agent rate were described on reduction measures of the carbon consumption and problem of the measures referring to the example of reducing agent rate of the present state blast furnace concerning blast operation and reactive improvement. And, carried out concrete measures were introduced in order to aim at the low reducing agent rate operation. The following results were obtained. 1) Since it has reached the already high reaction efficiency in present state blast furnace, it is not easy to attempt further reduction of the reducing agent rate. 2) The blast furnace use of high reactivity coke or reduced iron is equal level or over it in comparison with the reduction effect by the assumed blast operation in this paper. 3) The promotion of coke reaction load with the gasification is worried, when it aims at the low reducing agent rate operation by the high reactivity coke use. 4) It is estimated that the threshold also exists for the reducibility of competing ore, when it aims at the low reducing agent rate operation using the high reactivity coke. 5) The use of the low SiO{sub 2} sinter is effective for the improvement on the permeability in the blast furnace, when it aims at the low fuel rate operation. However, the new technology of the permeability improvement is desired, since there is a limit for low SiO{sub 2} of the sintered ore, when future raw material supply and demand is considered.

  5. Statistics of Local Extremes

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Bierbooms, W.; Hansen, Kurt Schaldemose

    2003-01-01

    The gust events described in the IEC-standard are formulated as coherent gusts of an inherent deterministic character, whereas the gusts experienced in real situation are of a stochastic nature with a limited spatial extension. This conceptual differencemay cause substantial differences in the load......, 1996]. However, dealing with wind turbine design, not only detailed knowledge on the spatial/time structure of the gust event is required. The probabilityof occurrence of a gust event with a given wind speed amplitude/magnitude is equally important. This theme is addressed in the present report......"Modelling of Extreme Gusts for Design Calculations " (NEWGUST), which is co-funded through JOULEIII on contract no. JOR3-CT98-0239....

  6. Ultimate deformation capacity of reinforced concrete slabs underblast load

    NARCIS (Netherlands)

    Doormaal, J.C.A.M. van; Weerheijm, J.

    1996-01-01

    In this paper a test method to determine the deformation capacity and the resistance-deformation curve of blast-loaded slabs is described. This method was developed at TNO-PML. The method has been used to determine the ultimate deformation capacity of some simply supported reinforced concrete slabs

  7. Experimental approach to shape field relevant blast wave profiles in compressed gas-driven shock tube

    Directory of Open Access Journals (Sweden)

    Aravind eSundaramurthy

    2014-12-01

    Full Text Available Detonation of a high explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects even at farther distances, which is termed as primary blast injury, which is the theme of this work. The shock-blast profile is characterized with blast overpressure, positive time duration, and impulse as shock-blast wave parameters (SWPs. These parameters in turn are a function of field factors, such as the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (Chandra et al., 2011;Sundaramurthy et al., 2012;Skotak et al., 2013, the profile not only determines the survival of the animal but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, exact replication of shock profile (magnitude and shape can be related to field explosions and can be a standard in comparing results across different laboratories. 40 experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68 to 1209.68 mm, measurement location, and type of driver gas (nitrogen, helium. The relationships between SAPs and the resulting shock-blast profiles are characterized. Finally, shock-blast profiles of a TNT explosion from ConWep software is compared with the profiles obtained

  8. Rapid evolution of avirulence genes in rice blast fungus Magnaporthe oryzae

    OpenAIRE

    Huang, Ju; Si, Weina; Deng, Qiming; Li, Ping; Yang, Sihai

    2014-01-01

    Background Rice blast fungus Magnaporthe oryzae is one of the most devastating pathogens in rice. Avirulence genes in this fungus share a gene-for-gene relationship with the resistance genes in its host rice. Although numerous studies have shown that rice blast R-genes are extremely diverse and evolve rapidly in their host populations, little is known about the evolutionary patterns of the Avr-genes in the pathogens. Results Here, six well-characterized Avr-genes and seven randomly selected n...

  9. A Numerical Method for Blast Shock Wave Analysis of Missile Launch from Aircraft

    Directory of Open Access Journals (Sweden)

    Sebastian Heimbs

    2015-01-01

    Full Text Available An efficient empirical approach was developed to accurately represent the blast shock wave loading resulting from the launch of a missile from a military aircraft to be used in numerical analyses. Based on experimental test series of missile launches in laboratory environment and from a helicopter, equations were derived to predict the time- and position-dependent overpressure. The method was finally applied and validated in a structural analysis of a helicopter tail boom under missile launch shock wave loading.

  10. Blast-Induced Acceleration in a Shock Tube: Distinguishing Primary and Tertiary Blast Injury

    Science.gov (United States)

    2016-10-01

    which envelops the head as well as some aerodynamic drag (i.e. dynamic pressure creating blast wind). The use of animal models to investigate...facing the blast and 37 blasts were recorded with the animals in a free- flying vertical position. Prone animals were strapped to a table using cargo...High-speed video system o Unique release mechanism - First test of blast on mid-air objects - First test of blast on free- flying pressure

  11. Performance of Pre-Stressed Sandwich Composites Subjected to Shock Wave Loading

    Directory of Open Access Journals (Sweden)

    Shukla A.

    2010-06-01

    Full Text Available The present paper experimentally studies the dynamic behaviour of prestressed sandwich composites under blast loading. The in-plane static compression loadings are implemented on the sandwich composites before they are subjected to the transverse shock wave loading. Three different pre-stress levels are chosen. 3-D realtime deformation data are captured by two high-speed photography systems: a backview Digital Image Correlation (DIC system and a side-view camera system. The results show that pre-stresses can induce local buckling in the front face-sheet of sandwich composites, consequently reduce the blast resistance of sandwich composites.

  12. REINFORCED CONCRETE SILO DEMOLITION BY BLASTING

    Directory of Open Access Journals (Sweden)

    Josip Krsnik

    1993-12-01

    Full Text Available This paper represents the demolition of reinforced concrete silo by blasting. The loadbearing structure was blasted so that the weight of the silo itself done most of the felling (the paper is published in Croatian.

  13. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects.

    Science.gov (United States)

    Courtney, Amy C; Andrusiv, Lubov P; Courtney, Michael W

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile. © 2012 American Institute of Physics

  14. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

    Science.gov (United States)

    Courtney, Amy C.; Andrusiv, Lubov P.; Courtney, Michael W.

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile.

  15. CONTROL OF FRAGMENTATION BY BLASTING

    OpenAIRE

    Božić, Branko

    1998-01-01

    The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the q...

  16. Porcine head response to blast

    Directory of Open Access Journals (Sweden)

    Jay eShridharani

    2012-05-01

    Full Text Available Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposed porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110-740 kPa peak incident overpressure with scaled durations from 1.3-6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. The bulk head acceleration and the pressure at the surface of the head and in the cranial cavity were measured. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within thirty seconds and the remaining two recovered within 8 minutes following bagging and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80-685 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385-3845 G’s and were well correlated with peak incident overpressure (R2=0.90. One standard deviation corridors for the surface pressure, intracranial pressure, and head acceleration are presented to provide experimental data for

  17. Asymmetric propagation of airblast from bench blasting

    OpenAIRE

    Segarra Catasús, Pablo; Sanchidrián Blanco, José Angel; López Sánchez, Lina María; Domingo, Jesús Felix

    2011-01-01

    This paper investigates the propagation of airblast from quarry blasting. Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and polar coordinates of the point of interest (distance to the blast and azimuth with respect to the free face of the blast). The model is in the form of the product of a classical scaled distance attenuation law times a directional correction factor. The...

  18. Service robot for hull-blasting

    OpenAIRE

    Ortiz Zaragoza, Francisco José; Iborra García, Andrés José; Álvarez Torres, María Bárbara; Marín García, Fulgencio; Fernández Meroño, José María

    2001-01-01

    Present grit blasting technology for hull cleaning is very pollutant, environmentally unaffordable, and it is progressively forbidden in the most environmental countries (mainly north of Europe). At the time being, the above methodology has been partially substituted by ultra highpressure water blasting, however they do not show as good performance as the grit blasting systems. This paper describes a service robot for hull blasting. The technology we developed consists of the cleanin...

  19. Influence of steel fibres on the blast response of normal-strength and high-strength reinforced concrete columns

    Science.gov (United States)

    Hammoud, A.; Aoude, H.

    2017-09-01

    This paper examines the influence of steel fibres on the blast performance of normal-strength concrete and high-strength concrete columns. As part of the study, four normal-strength and high-strength concrete columns built with and without steel fibres are tested under simulated blast loads using the shock-tube facility at the University of Ottawa. The specimens include two columns built with plain concrete and two columns built with steel fibre-reinforced concrete. The results show that the addition of steel fibres in reinforced concrete columns leads to important enhancements in blast performance, with improved control of mid-span displacements at equivalent blasts and increased damage tolerance.

  20. Skull Flexure from Blast Waves: A Mechanism for Brain Injury with Implications for Helmet Design

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2009-04-30

    Traumatic brain injury [TBI] has become a signature injury of current military conflicts, with debilitating, costly, and long-lasting effects. Although mechanisms by which head impacts cause TBI have been well-researched, the mechanisms by which blasts cause TBI are not understood. From numerical hydrodynamic simulations, we have discovered that non-lethal blasts can induce sufficient skull flexure to generate potentially damaging loads in the brain, even without a head impact. The possibility that this mechanism may contribute to TBI has implications for injury diagnosis and armor design.

  1. Mitigation of Blast Effects on Protective Structures by Aluminum Foam Panels

    Directory of Open Access Journals (Sweden)

    Doyeon Byun

    2012-06-01

    Full Text Available Aluminum foams have low density and are attractive materials to mitigate high-speed pressure by blast loads due to high-energy absorption capabilities. In order to develop nonlinear material models for the aluminum foam with different density, mechanical properties of the foam and foam panels under compression, tension, shear and bending moment were obtained by numerous tests. Through the explicit analyses of the foam panels by LS-DYNA, the derived models were verified. Performance of the foam panels with different scaled distances was evaluated by blast tests. Thickness, density and skin plate properties of the panel are the most important parameters to estimate the transmitted pressure to protective structures. Because the pressure of close range blast loading is not uniform, the skin plays an important role in the behavior of the foam. Numerical simulations considering the parameters provided basic design guidelines for the protective structures with sacrificial foam panels. Properly designed panels for the required blast loads can control the transmitted pressure to the target structure under a certain pressure on the yield strength of the foam.

  2. Prediction of Near-Field Wave Attenuation Due to a Spherical Blast Source

    Science.gov (United States)

    Ahn, Jae-Kwang; Park, Duhee

    2017-11-01

    Empirical and theoretical far-field attenuation relationships, which do not capture the near-field response, are most often used to predict the peak amplitude of blast wave. Jiang et al. (Vibration due to a buried explosive source. PhD Thesis, Curtin University, Western Australian School of Mines, 1993) present rigorous wave equations that simulates the near-field attenuation to a spherical blast source in damped and undamped media. However, the effect of loading frequency and velocity of the media have not yet been investigated. We perform a suite of axisymmetric, dynamic finite difference analyses to simulate the propagation of stress waves induced by spherical blast source and to quantify the near-field attenuation. A broad range of loading frequencies, wave velocities, and damping ratios are used in the simulations. The near-field effect is revealed to be proportional to the rise time of the impulse load and wave velocity. We propose an empirical additive function to the theoretical far-field attenuation curve to predict the near-field range and attenuation. The proposed curve is validated against measurements recorded in a test blast.

  3. Extremely Preterm Birth

    Science.gov (United States)

    ... Education & Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm ... Pamphlets - Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” ...

  4. The effects of a strength and neuromuscular exercise programme for the lower extremity on knee load, pain and function in obese children and adolescents: study protocol for a randomised controlled trial

    OpenAIRE

    Horsak, Brian; Artner, David; Baca, Arnold; Pobatschnig, Barbara; Greber-Platzer, Susanne; Nehrer, Stefan; Wondrasch, Barbara

    2015-01-01

    Background Childhood obesity is one of the most critical and accelerating health challenges throughout the world. It is a major risk factor for developing varus/valgus misalignments of the knee joint. The combination of misalignment at the knee and excess body mass may result in increased joint stresses and damage to articular cartilage. A training programme, which aims at developing a more neutral alignment of the trunk and lower limbs during movement tasks may be able to reduce knee loading...

  5. Domain enhanced lookup time accelerated BLAST

    Directory of Open Access Journals (Sweden)

    Boratyn Grzegorz M

    2012-04-01

    Full Text Available Abstract Background BLAST is a commonly-used software package for comparing a query sequence to a database of known sequences; in this study, we focus on protein sequences. Position-specific-iterated BLAST (PSI-BLAST iteratively searches a protein sequence database, using the matches in round i to construct a position-specific score matrix (PSSM for searching the database in round i + 1. Biegert and Söding developed Context-sensitive BLAST (CS-BLAST, which combines information from searching the sequence database with information derived from a library of short protein profiles to achieve better homology detection than PSI-BLAST, which builds its PSSMs from scratch. Results We describe a new method, called domain enhanced lookup time accelerated BLAST (DELTA-BLAST, which searches a database of pre-constructed PSSMs before searching a protein-sequence database, to yield better homology detection. For its PSSMs, DELTA-BLAST employs a subset of NCBI’s Conserved Domain Database (CDD. On a test set derived from ASTRAL, with one round of searching, DELTA-BLAST achieves a ROC5000 of 0.270 vs. 0.116 for CS-BLAST. The performance advantage diminishes in iterated searches, but DELTA-BLAST continues to achieve better ROC scores than CS-BLAST. Conclusions DELTA-BLAST is a useful program for the detection of remote protein homologs. It is available under the “Protein BLAST” link at http://blast.ncbi.nlm.nih.gov. Reviewers This article was reviewed by Arcady Mushegian, Nick V. Grishin, and Frank Eisenhaber.

  6. Membrane characteristics for biological blast overpressure testing using blast simulators.

    Science.gov (United States)

    Alphonse, Vanessa D; Siva Sai Sujith Sajja, Venkata; Kemper, Andrew R; Rizel, Dave V; Duma, Stefan M; VandeVord, Pamela J

    2014-01-01

    Blast simulators often use passive-rupture membranes to generate shock waves similar to free-field blasts. The purpose of this study was to compare rupture patterns and pressure traces of three distinct membrane materials for biological and biomechanical blast studies. An Advanced Blast Simulator (ABS) located at the Center for Injury Biomechanics at Virginia Tech was used to test membrane characteristics. Acetate, Mylar, and aluminum sheets with different thicknesses were used to obtain pressures between 70–210 kPa. Static pressure was measured inside the tube at the test section using piezoelectric pressure sensors. Peak overpressure, positive duration, and positive impulse were calculated for each test. Rupture patterns and characteristic pressure traces were unique to each membrane type and thickness. Shock wave speed ranged between 1.2-1.8 Mach for static overpressures of 70–210 kPa. Acetate membranes fragmented sending pieces down the tube, but produced ideal (Friedlander) pressure traces. Mylar membranes bulged without fragmenting, but produced less-than-ideal pressure traces. Aluminum membranes did not fragment and produced ideal pressure traces. However, the cost of manufacturing and characterizing aluminum membranes should be considered during membrane selection. This study illustrates the advantages and disadvantages of using Mylar, acetate, and aluminum for passive rupture membranes for blast simulators.

  7. Two-material optimization of plate armour for blast mitigation using hybrid cellular automata

    Science.gov (United States)

    Goetz, J.; Tan, H.; Renaud, J.; Tovar, A.

    2012-08-01

    With the increased use of improvised explosive devices in regions at war, the threat to military and civilian life has risen. Cabin penetration and gross acceleration are the primary threats in an explosive event. Cabin penetration crushes occupants, damaging the lower body. Acceleration causes death at high magnitudes. This investigation develops a process of designing armour that simultaneously mitigates cabin penetration and acceleration. The hybrid cellular automaton (HCA) method of topology optimization has proven efficient and robust in problems involving large, plastic deformations such as crash impact. Here HCA is extended to the design of armour under blast loading. The ability to distribute two metallic phases, as opposed to one material and void, is also added. The blast wave energy transforms on impact into internal energy (IE) inside the solid medium. Maximum attenuation occurs with maximized IE. The resulting structures show HCA's potential for designing blast mitigating armour structures.

  8. Elastomeric Polymers for Retrofitting of Reinforced Concrete Structures against the Explosive Effects of Blast

    Directory of Open Access Journals (Sweden)

    S. N. Raman

    2012-01-01

    Full Text Available The main distinction of blast load from other types of dynamic loadings is its impulsive nature, where the loads usually act for a very short duration but transmit very high impulsive pressures. This paper presents an overview of the present retrofitting techniques in use to enhance the capacity of structural elements to withstand the effects of blast loads, and introduces an alternative retrofitting approach by utilizing polymer coatings. The authors have demonstrated the positive effects of this approach by conducting a numerical investigation on the behavior of an unretrofitted reinforced concrete panel subjected to the blast load from a 2 kg charge at 1.6 m stand-off distance, and subsequently comparing its performance with several polymer coated panels. The analysis was performed by using an explicit nonlinear finite element (FE code. The results demonstrate the contributions of this technique in terms of panel displacement control and energy dissipation. Considering that the polymer coating can also act as a protective layer in improving the durability of structural materials, this technique can also be optimized favorably to enhance the overall sustainability of structures.

  9. Toxicology of blast overpressure.

    Science.gov (United States)

    Elsayed, N M

    1997-07-25

    Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that are occurring worldwide with greater frequency. Exposure to incident BOP waves can cause auditory and non-auditory damage. The primary targets for BOP damage are the hollow organs, ear, lung and gastrointestinal tract. In addition, solid organs such as heart, spleen and brain can also be injured upon exposure. However, the lung is more sensitive to damage and its injury can lead to death. The pathophysiological responses, and mortality have been extensively studied, but little attention, was given to the biochemical manifestations, and molecular mechanism(s) of injury. The injury from BOP has been, generally, attributed to its external physical impact on the body causing internal mechanical damage. However, a new hypothesis has been proposed based on experiments conducted in the Department of Respiratory Research, Walter Reed Army Institute of Research, and later in the Department of Occupational Health, University of Pittsburgh. This hypothesis suggests that subtle biochemical changes namely, free radical-mediated oxidative stress occur and contribute to BOP-induced injury. Understanding the etiology of these changes may shed new light on the molecular mechanism(s) of injury, and can potentially offer new strategies for treatment. In this symposium. BOP research involving auditory, non-auditory, physiological, pathological, behavioral, and biochemical manifestations as well as predictive modeling and current treatment modalities of BOP-induced injury are discussed.

  10. Blast impact behaviour of concrete with different fibre reinforcement

    Directory of Open Access Journals (Sweden)

    Drdlová Martina

    2015-01-01

    Full Text Available The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concrete prism specimens have been subjected to the determination of mechanical parameters (compressive and flexural strength at quasi-static load. The blast tests were conducted on the slab specimens prepared from selected mixtures. The material characteristics and explosion test data have been used for numerical investigation, which defined the optimal wall composition and dimensions of the concrete element which should resist the explosion defined by type, size, weight and placement of the blast. In the next step the test elements resistance was verified by real explosion test.

  11. Evaluation of Liquefaction Susceptibility of Clean Sands after Blast Densification

    Science.gov (United States)

    Vega Posada, Carlos Alberto

    The effect of earthquakes on infrastructure facilities is an important topic of interest in geotechnical research. A key design issue for such facilities is whether or not liquefaction will occur during an earthquake. The consequences of this type of ground failure are usually severe, resulting in severe damage to a facility and in some cases the loss of human life. One approach to minimize the effect of liquefaction is to improve the ground condition by controlled blasting. The main limitations of the blast densification technique are that the design is mostly empirical and verification studies of densification have resulted in contradictory results in some case studies. In such cases, even though the ground surface settles almost immediately after blasting, common verification tests such as the cone penetration test (CPT), standard penetration test (SPT), and shear wave velocity test (Vs) suggest that the soil mass has not been improved at all. This raises concerns regarding the future performance of the soil and casts doubts on whether or not the improved deposit is still susceptible to liquefaction. In this work, a blast densification program was implemented at the Oakridge Landfill located in Dorchester County, SC, to gain information regarding the condition of a loose sand deposit during and after each blast event. In addition, an extensive laboratory testing program was conducted on reconstituted sand specimens to evaluate the mechanical behavior of saturated and gassy, medium dense sands during monotonic and cyclic loading. The results from the field and laboratory program indicate that gas released during blasting can remain trapped in the soil mass for several years, and this gas greatly affects the mechanical behavior of the sand. Gas greatly increases the liquefaction resistance of the soil. If the gas remains in the sand over the life of a project, then it will maintain this increased resistance to liquefaction, whether or not the penetration

  12. Simulating geometrically complex blast scenarios

    Directory of Open Access Journals (Sweden)

    Ian G. Cullis

    2016-04-01

    Full Text Available The effects of blast waves generated by energetic and non-energetic sources are of continuing interest to the ballistics research community. Modern conflicts are increasingly characterised by asymmetric urban warfare, with improvised explosive devices (IEDs often playing a dominant role on the one hand and an armed forces requirement for minimal collateral effects from their weapons on the other. These problems are characterised by disparate length- and time-scales and may also be governed by complex physics. There is thus an increasing need to be able to rapidly assess and accurately predict the effects of energetic blast in topologically complex scenarios. To this end, this paper presents a new QinetiQ-developed advanced computational package called EAGLE-Blast, which is capable of accurately resolving the generation, propagation and interaction of blast waves around geometrically complex shapes such as vehicles and buildings. After a brief description of the numerical methodology, various blast scenario simulations are described and the results compared with experimental data to demonstrate the validation of the scheme and its ability to describe these complex scenarios accurately and efficiently. The paper concludes with a brief discussion on the use of the code in supporting the development of algorithms for fast running engineering models.

  13. Quick reproduction of blast-wave flow-field properties of nuclear, TNT, and ANFO explosions

    Science.gov (United States)

    Groth, C. P. T.

    1986-04-01

    In many instances, extensive blast-wave flow-field properties are required in gasdynamics research studies of blast-wave loading and structure response, and in evaluating the effects of explosions on their environment. This report provides a very useful computer code, which can be used in conjunction with the DNA Nuclear Blast Standard subroutines and code, to quickly reconstruct complete and fairly accurate blast-wave data for almost any free-air (spherical) and surface-burst (hemispherical) nuclear, trinitrotoluene (TNT), or ammonium nitrate-fuel oil (ANFO) explosion. This code is capable of computing all of the main flow properties as functions of radius and time, as well as providing additional information regarding air viscosity, reflected shock-wave properties, and the initial decay of the flow properties just behind the shock front. Both spatial and temporal distributions of the major blast-wave flow properties are also made readily available. Finally, provisions are also included in the code to provide additional information regarding the peak or shock-front flow properties over a range of radii, for a specific explosion of interest.

  14. Surface modification of titanium using steel slag ball and shot blasting treatment for biomedical implant applications

    Science.gov (United States)

    Arifvianto, Budi; Suyitno; Mahardika, Muslim

    2013-08-01

    Surface modification is often performed using grit or shot blasting treatment for improving the performances of biomedical implants. The effects of blasting treatments using steel slag balls and spherical shots on the surface and subsurface of titanium were studied in this paper. The treatments were conducted for 60-300 s using 2-5 mm steel slag balls and 3.18 mm spherical shots. The surface morphology, roughness, and elemental composition of titanium specimens were examined prior to and after the treatments. Irregular and rough titanium surfaces were formed after the treatment with the steel slag balls instead of the spherical shots. The former treatment also introduced some bioactive elements on the titanium surface, but the latter one yielded a harder surface layer. In conclusion, both steel slag ball and shot blasting treatment have their own specialization in modifying the surface of metallic biomaterials. Steel slag ball blasting is potential for improving the osseointegration quality of implants; but the shot blasting is more appropriate for improving the mechanical properties of temporary and load bearing implants, such as osteosynthesis plates.

  15. Blood-brain barrier dysfunction after primary blast injury in vitro.

    Science.gov (United States)

    Hue, Christopher D; Cao, Siqi; Haider, Syed F; Vo, Kiet V; Effgen, Gwen B; Vogel, Edward; Panzer, Matthew B; Bass, Cameron R Dale; Meaney, David F; Morrison, Barclay

    2013-10-01

    The incidence of blast-induced traumatic brain injury (bTBI) has increased substantially in recent military conflicts. However, the consequences of bTBI on the blood-brain barrier (BBB), a specialized cerebrovascular structure essential for brain homeostasis, remain unknown. In this study, we utilized a shock tube driven by compressed gas to generate operationally relevant, ideal pressure profiles consistent with improvised explosive devices (IEDs). By multiple measures, the barrier function of an in vitro BBB model was disrupted following exposure to a range of controlled blast loading conditions. Trans-endothelial electrical resistance (TEER) decreased acutely in a dose-dependent manner that was most strongly correlated with impulse, as opposed to peak overpressure or duration. Significantly increased hydraulic conductivity and solute permeability post-injury further confirmed acute alterations in barrier function. Compromised ZO-1 immunostaining identified a structural basis for BBB breakdown. After blast exposure, TEER remained significantly depressed 2 days post-injury, followed by spontaneous recovery to pre-injury control levels at day 3. This study is the first to report immediate disruption of an in vitro BBB model following primary blast exposure, which may be important for the development of novel helmet designs to help mitigate the effects of blast on the BBB.

  16. Thermal oxidation of medical Ti6Al4V blasted with ceramic particles: Effects on the microstructure, residual stresses and mechanical properties.

    Science.gov (United States)

    Lieblich, M; Barriuso, S; Multigner, M; González-Doncel, G; González-Carrasco, J L

    2016-02-01

    Roughening of Ti6Al4V by blasting with alumina or zirconia particles improves the mechanical fixation of implants by increasing the surface area available for bone/implant apposition. Additional thermal oxidation treatments of the blasted alloy have already shown to be a complementary low-cost solution to enhancing the in vitro biocompatibility and corrosion resistance of the alloy. In this work, the effects of oxidation treatment on a grit blasted Ti6Al4V biomedical alloy have been analysed in order to understand the net effect of the combined treatments on the alloy fatigue properties. Synchrotron radiation diffraction experiments have been performed to measure residual stresses before and after the treatments and microstructural and hardness changes have been determined. Although blasting of Ti6Al4V with small spherical zirconia particles increases the alloy fatigue resistance with respect to unblasted specimens, fatigue strength after oxidation decreases below the unblasted value, irrespective of the type of particle used for blasting. Moreover, at 700°C the as-blasted compressive residual stresses (700MPa) are not only fully relaxed but even moderate tensile residual stresses, of about 120MPa, are found beneath the blasted surfaces. Contrary to expectations, a moderate increase in hardness occurs towards the blasted surface after oxidation treatments. This can be attributed to the fact that grit blasting modifies the crystallographic texture of the Ti6Al4V shifting it to a random texture, which affects the hardness values as shown by additional experiments on cold rolled samples. The results indicate that the oxidation treatment performed to improve biocompatibility and corrosion resistance of grit blasted Ti6Al4V should be carried out with caution since the alloy fatigue strength can be critically diminished below the value required for high load-bearing components. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Porcine head response to blast.

    Science.gov (United States)

    Shridharani, Jay K; Wood, Garrett W; Panzer, Matthew B; Capehart, Bruce P; Nyein, Michelle K; Radovitzky, Raul A; Bass, Cameron R 'dale'

    2012-01-01

    Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposes porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110 to 740 kPa peak incident overpressure with scaled durations from 1.3 to 6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. Instrumentation was placed on the porcine head to measure bulk acceleration, pressure at the surface of the head, and pressure inside the cranial cavity. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within 30 s and the remaining two recovered within 8 min following respiratory assistance and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80 to 390 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385 to 3845 G's and were well correlated with peak incident overpressure (R(2) = 0.90). One SD corridors for the surface pressure, intracranial pressure (ICP), and head acceleration are

  18. Efficacy of visor and helmet for blast protection assessed using a computational head model

    Science.gov (United States)

    Singh, D.; Cronin, D. S.

    2017-11-01

    Head injury resulting from blast exposure has been identified as a challenge that may be addressed, in part, through improved protective systems. Existing detailed head models validated for blast loading were applied to investigate the influence of helmet visor configuration, liner properties, and shell material stiffness. Response metrics including head acceleration and intracranial pressures (ICPs) generated in brain tissue during primary blast exposure were used to assess and compare helmet configurations. The addition of a visor was found to reduce peak head acceleration and positive ICPs. However, negative ICPs associated with a potential for injury were increased when a visor and a foam liner were present. In general, the foam liner material was found to be more significant in affecting the negative ICP response than positive ICP or acceleration. Shell stiffness was found to have relatively small effects on either metric. A strap suspension system, modeled as an air gap between the head and helmet, was more effective in reducing response metrics compared to a foam liner. In cases with a foam liner, lower-density foam offered a greater reduction of negative ICPs. The models demonstrated the "underwash" effect in cases where no foam liner was present; however, the reflected pressures generated between the helmet and head did not translate to significant ICPs in adjacent tissue, when compared to peak ICPs from initial blast wave interaction. This study demonstrated that the efficacy of head protection can be expressed in terms of load transmission pathways when assessed with a detailed computational model.

  19. Validation of Laboratory Animal and Surrogate Human Models in Primary Blast Injury Studies.

    Science.gov (United States)

    Chandra, Namas; Sundaramurthy, Aravind; Gupta, Raj K

    2017-03-01

    Blast-induced neurotrauma has affected more than 300,000 service members. It is important to understand the effect of single and repeated shock-blast wave exposures on the neuropsychological behavior of soldiers, to offer them better protection, diagnostics, and treatment. Preclinical animal models and helmet design studies on human surrogate models have relied on the use of compression gas-driven shock tubes. Traditional shock tubes are so simple that if not carefully designed and operated, the test results can easily introduce detrimental artifacts clouding the conclusions. In this work, we present live-fire test results of an instrumented human surrogate head-neck model and compare with the data obtained in a carefully designed shock tube. We present various features incorporated in the shock tube design that led to better fidelity between live-fire and laboratory shock-blast conditions. The effect of specimen placement, choice of driver gas, pressure and volume of driver, end-plate conditions, and measurement techniques all determine the successful replication of live-fire loading conditions. These parameters become more important when conducting animal testing as the totality of loading will dictate the injury severity and type which ultimately will determine the mechanisms of blast-induced neurotrauma and hence their prevention and treatment strategies. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  20. MEASUREMENT IN BLAST HOLE STEM AND INFLUENCE OF STEMING MATERIAL ON BLASTING QUALITY

    Directory of Open Access Journals (Sweden)

    Mario Dobrilović

    2005-12-01

    Full Text Available Paper presents results of blast hole stem materials, that were conducted to assert best stem materials for surface blasting in quarry of technical / construction stone. Blasting has been performed with equal explosives and test-minefield parameters (length of the stem, volume of the explosive charge, mine-drill depth, and angle on various sites / quarry. Results are guidelines in materials to be chosen in surface blasting of quarry works, adding to quality of mining works and reduction of costs.

  1. Communication path for extreme environments

    Science.gov (United States)

    Jorgensen, Charles C. (Inventor); Betts, Bradley J. (Inventor)

    2010-01-01

    Methods and systems for using one or more radio frequency identification devices (RFIDs), or other suitable signal transmitters and/or receivers, to provide a sensor information communication path, to provide location and/or spatial orientation information for an emergency service worker (ESW), to provide an ESW escape route, to indicate a direction from an ESW to an ES appliance, to provide updated information on a region or structure that presents an extreme environment (fire, hazardous fluid leak, underwater, nuclear, etc.) in which an ESW works, and to provide accumulated thermal load or thermal breakdown information on one or more locations in the region.

  2. Reducing Drill and Blast Cost through Blast Optimisation – A Case ...

    African Journals Online (AJOL)

    Michael O. Mensah

    2015-12-02

    Dec 2, 2015 ... operations suggests that although mine blasts generally fragment rock to be handled by the mining process, there is potential optimal fragmentation to improve the productivity and reduce cost of all downstream processes (Bozic,. 1998). Optimising blast design parameters could reduce the drill and blast ...

  3. Modelo de análisis de cargas máximas en aerogeneradores producidas por vientos extremos // Model of analysis of maximum loads in wind generators produced by extreme winds.

    Directory of Open Access Journals (Sweden)

    Omar Herrera - Sánchez

    2010-05-01

    renewable source of energy totally, either because the country isvery small, or because it coincides the area of more potential fully with that of high risk. To counteractthis situation, a model of analysis of maxims loads has been elaborated taken place the extremewinds in wind turbines of great behavior. This model has the advantage of determining, in a chosenplace, for the installation of a wind farm, the micro-areas with higher risk of wind loads above theacceptable for the standard classes of wind turbines.Key words: Wind turbines, wind loads, modeling of wind farm.

  4. Extreme wave and wind response predictions

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Olsen, Anders S.; Mansour, Alaa E.

    2011-01-01

    The aim of the paper is to advocate effective stochastic procedures, based on the First Order Reliability Method (FORM) and Monte Carlo simulations (MCS), for extreme value predictions related to wave and wind-induced loads.Due to the efficient optimization procedures implemented in standard FORM...

  5. Tyre-blast injuries.

    Science.gov (United States)

    Murty, O P

    2009-05-01

    A teenager college student was fatally injured by burst tyre air pressure while waiting on a public bus stand to catch a bus to reach her college at Kuala Lumpur. She accidentally came near the wheel while boarding when tube and tyre got burst .The air pressure had blown the girl in the air and she subsequently fell on a rough surface. The iron-locking rim of the wheel acted as a missile and hit the girl. She died on her way to the hospital. A medico-legal autopsy was performed which showed extensive injuries in the cranial and chest cavity. Head had large scalp laceration with diffuse separation and gaping from in the vault region; skull bones were fractured. Chest cavity had extensive rib fractures, lacerated lungs and haemo-thorax while externally there was no obvious injury. It requires intensive care management and screening of the victims. Tyre-blast injuries are not so common. This case exposes the hazard due to burst tyre.

  6. Blast Load Simulator Experiments for Computational Model Validation: Report 2

    Science.gov (United States)

    2017-02-01

    uncertainty information in the form of confidence intervals for peak pressure and impulse result in a data set that can be used to evaluate the...simulations of these explosive events and their effects. These codes are continuously improving, but still require validation against experimental data to... data at several locations on the surfaces of the structure. The BLS is a highly tunable compressed gas-driven, closed-end shock tube designed to

  7. Blast Load Simulator Experiments for Computational Model Validation Report 3

    Science.gov (United States)

    2017-07-01

    these explosive events and their effects. These codes are continuously improving, but still require validation against experimental data to...these explosive events and their effects. These codes are continuously improving, but they still require validation against experimental data to...driver material from reaching the pressure gauges during the recorded time frame for those experiments. A comparison of representative pressure waveforms

  8. Blast Load Simulator Experiments for Computational Model Validation: Report 1

    Science.gov (United States)

    2016-08-01

    5 Figure 4. Expansion rings and cascade...Obtain degrees (angle) 0.01745329 radians feet 0.3048 meters inches 0.0254 meters pounds (force) 4.448222 newtons pounds (force) per foot 14.59390... newtons per meter pounds (mass) 0.45359237 kilograms ERDC/GSL TR-16-27 1 1 Introduction 1.1 Background The U.S. Department of Defense

  9. Blast load effects research in dry and wet soil

    CSIR Research Space (South Africa)

    Ahmed, R

    2014-09-01

    Full Text Available measured. One such variable is the soil moisture content when considering buried charges. Tests were conducted on 8 kg charges buried in both wet and dry soils at three different Stand-Off Distances (SOD). The measured impulse was consistently higher...

  10. Blast Loading of Epoxy Panels Using a Shock Tube

    Science.gov (United States)

    Pankow, Mark; Waas, Anthony M.; Bednarcyk, Brett

    2010-01-01

    The high strain rate mechanical response of thin polymer plates has been studied using a modified shock tube. Diagnostics include the pressure-time history of the incident and reflected pulses and the use of digital image correlation (DIC) techniques to extract the time-history of the out-of-plane displacement distribution. Additionally, finite element models have been developed to understand the plate response and to validate and modify plate material constitutive models that have been proposed.

  11. Ultimate loading of wind turbines

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Ronold, K.; Ejsing Jørgensen, Hans

    1999-01-01

    to establish partial safety factors for design of such components against this failure mode, structuralreliability methods must be applied. This type of analysis accounts for the variability of the external (wind) loading (as addressed in the analyses of the general wind climate) - and thereby the induced......An extreme loading study has been conducted comprising a general wind climate analysis as well as a wind turbine reliability study. In the wind climate analysis, the distribution of the (horizontal) turbulence standard deviation, conditioned on the meanwind speed, has been approximated by fitting......, a design turbulence intensity for off-shore application is proposed which, in the IEC code framework, is applicable for extreme as well as for fatigue loaddetermination. In order to establish a rational method to analyse wind turbine components with respect to failure in ultimate loading, and in addition...

  12. Heavy-Load Lifting

    DEFF Research Database (Denmark)

    Bloomquist, Kira; Oturai, Peter; Steele, Megan L

    2017-01-01

    PURPOSE: Despite a paucity of evidence, prevention guidelines typically advise avoidance of heavy lifting in an effort to protect against breast cancer-related lymphedema. This study compared acute responses in arm swelling and related symptoms after low- and heavy-load resistance exercise among...... women at risk of lymphedema while receiving adjuvant taxane-based chemotherapy. METHODS: This is a randomized, cross-over equivalence trial. Women receiving adjuvant taxane-based chemotherapy for breast cancer who had undergone axillary lymph node dissection (n=21) participated in low- (60-65% 1...... repetition maximum (RM), two sets of 15-20 repetitions) and heavy-load (85-90% 1RM, three sets of 5-8 repetition) upper-extremity resistance exercise separated by a one-week wash-out period. Swelling was determined by bioimpedance spectroscopy and dual energy x-ray absorptiometry, with breast cancer...

  13. Mask materials for powder blasting

    NARCIS (Netherlands)

    Wensink, H.; Jansen, Henricus V.; Berenschot, Johan W.; Elwenspoek, Michael Curt

    Powder blasting, or abrasive jet machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials such as glass, silicon and ceramics. The particle jet (which

  14. High resolution powder blast micromachining

    NARCIS (Netherlands)

    Wensink, H.; Berenschot, Johan W.; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2000-01-01

    Powder blasting, or Abrasive Jet Machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials like glass, silicon and ceramics. By introducing electroplated

  15. Weather and Climate Extremes

    National Research Council Canada - National Science Library

    Krause, Paul

    1997-01-01

    .... All extremes are presented in terms of their location and date and, where supportive information is available in the professional literature, detailed discussions of the extreme event are provided...

  16. Legacy to the extreme

    NARCIS (Netherlands)

    A. van Deursen (Arie); T. Kuipers (Tobias); L.M.F. Moonen (Leon)

    2000-01-01

    textabstractWe explore the differences between developing a system using extreme programming techniques, and maintaining a legacy system. We investigate whether applying extreme programming techniques to legacy maintenance is useful and feasible.

  17. Zerg: a very fast BLAST parser library.

    Science.gov (United States)

    Paquola, Apuã C M; Machado, Abimael A; Reis, Eduardo M; Da Silva, Aline M; Verjovski-Almeida, Sergio

    2003-05-22

    Zerg is a library of sub-routines that parses the output from all NCBI BLAST programs (Blastn, Blastp, Blastx, Tblastn and Tblastx) and returns the attributes of a BLAST report to the user. It is optimized for speed, being especially useful for large-scale genomic analysis. Benchmark tests show that Zerg is over two orders of magnitude faster than some widely used BLAST parsers. http://bioinfo.iq.usp.br/zerg

  18. Patterns in Blast Injuries to the Hand

    OpenAIRE

    Hazani, Ron; Buntic, Rudolf F.; Brooks, Darrell

    2008-01-01

    Blast injuries to the hand are not just a wartime phenomenon but also quite common in rural communities throughout northern California. The purpose of this study is to review our experience with blast injuries in the community and review the most common patterns in an attempt to identify the pathomechanics of the hand injury and the reconstructive procedures that are required. This is a retrospective study of blast injuries to the hand treated between 1978 and 2006. Medical records, X-rays, a...

  19. Extreme winds in Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.

    1999-02-01

    Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity which is defined as the 50-year wind speed under standard conditions, i.e. ten-minute averages at the height 10 m over a uniform terrain with the roughness length 0.05 m. The sites are, from west, Skjern (15 years), Kegnaes (7 years), Sprogoe (20 years), and Tystofte (15 years). The data are ten minute averages of wind speed, wind direction, temperature and pressure. The last two quantities are used to determine the air density {rho}. The data are cleaned for terrain effects by means of a slightly modified WASP technique where the sector speed-up factors and roughness lengths are linearly smoothed with a direction resolution of one degree. Assuming geotropic balance, all the wind-velocity data are transformed to friction velocity u{sub *} and direction at standard conditions by means of the geotropic drag law for neutral stratification. The basic wind velocity in 30 deg. sectors are obtained through ranking of the largest values of the friction velocity pressure 1/2{rho}u{sub *}{sup 2} taken both one every two months and once every year. The main conclusion is that the basic wind velocity is significantly larger at Skjern, close to the west coast of Jutland, than at any of the other sites. Irrespective of direction, the present standard estimates of 50-year wind are 25 {+-} 1 m/s at Skern and 22 {+-} 1 m/s at the other three sites. These results are in agreement with those obtained by Jensen and Franck (1970) and Abild (1994) and supports the conclusion that the wind climate at the west coast of Jutland is more extreme than in any other part of the country. Simple procedures to translate in a particular direction sector the standard basic wind velocity to conditions with a different roughness length and height are presented. It is shown that a simple scheme makes it possible to calculate the total 50-year extreme load on a general structure without

  20. Concrete structures under impact loading rate effects

    NARCIS (Netherlands)

    Zielinski, A.J.

    1984-01-01

    Various structures may be subjected to accidental, impact loading. The behaviour of structures under that kind of extreme loading conditions is of vital importance for people's safety and environmental damage prevention. There is a need for reliable assessment methods for the local and the overall

  1. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  2. Effect of blasts on subject-specific computational models of skin and bone sections at various locations on the human body

    Directory of Open Access Journals (Sweden)

    Arnab Chanda

    2015-11-01

    Full Text Available Blast injuries are very common among soldiers deployed in politically unstable regions such as Afghanistan and Iraq, and also in a battle field anywhere in the world. Understanding the mechanics of interaction of blasts with the skin and bone at various parts of the human body is the key to designing effective personal protective equipment (PPE's which can mitigate blast impacts. In the current work, subject-specific 3D computational models of the skin (with the three layers namely the epidermis, dermis and the hypodermis (muscles and bone sections from various parts of the human body (such as the elbow, finger, wrist, cheek bone, forehead, shin etc. have been developed to study the effect of blast loading. Non-linear material properties have been adopted for the skin and stress impulses at the different skin layers and bone sections are estimated. To date, such an extensive study on the effect of blast loading on the human skin and bone has not been attempted. The results of this study would be indispensable for medical practitioners to understand the effect of blast trauma and plan effective post-traumatic surgical strategies, and also for developing better PPE designs for the military in the future.

  3. Novel Musculoskeletal Loading and Assessment System

    Science.gov (United States)

    Downs, Meghan E.

    2017-01-01

    Ground based and ISS (International Space Station) exercise research have shown that axial loading via two-point loading at the shoulders and load quality (i.e. consistent load and at least 1:1 concentric to eccentric ratio) are extremely important to optimize musculoskeletal adaptations to resistance exercise. The Advanced Resistance Exercise Device (ARED) is on ISS now and is the "state of the art" for resistance exercise capabilities in microgravity; however, the ARED is far too large and power consuming for exploration vehicles. The single cable exercise device design selected for MPCV (Multi-Purpose Crew Vehicle), does not readily allow for the two-point loading at the shoulders.

  4. Alkaline carbonates in blast furnace process

    Directory of Open Access Journals (Sweden)

    P. Besta

    2014-10-01

    Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

  5. genBlastG: using BLAST searches to build homologous gene models.

    Science.gov (United States)

    She, Rong; Chu, Jeffrey Shih-Chieh; Uyar, Bora; Wang, Jun; Wang, Ke; Chen, Nansheng

    2011-08-01

    BLAST users frequently expect to obtain homologous genes with certain similarity to their query genes. But what they get from BLAST searches are often collections of local alignments called high-scoring segment pairs (HSPs). On the other hand, most homology-based gene finders have been built using computation-intensive algorithms, without taking full advantage of BLAST searches that have been perfected over the last decades. Here we report an efficient algorithm, genBlastG that directly uses the HSPs reported by BLAST to define high-quality gene models. http://genome.sfu.ca/genblast/download.html

  6. Modeling the Blast Load Simulator Airblast Environment using First Principles Codes. Report 1, Blast Load Simulator Environment

    Science.gov (United States)

    2016-11-01

    calculations were conducted on differ- ent HPC platforms. Processor speeds and memory capacity varied for each of the platforms. Thus, there can be no...The 2-DC calculations used nominal 0.1-, 0.2-, or 0.5-cm cell sizes. Reflec- tive BCs were applied to the axis of symmetry and transmissive BCs were...Nickel Ideal Gas Sesame ERDC/GSL TR-16-31 172 Figure E2. Calculated initial pressure peaks as a function of EOS. (a) Gauge

  7. prevalence of rice blast and varietal screening in ghana

    African Journals Online (AJOL)

    search-screening site grown to an improved vari- ety, Tox 3050, was heavily blasted. There was no blast incidence at Damongo. In Upper Iiast. Region, there was severe incidence of blast in farmers' fields at Bawku and PVS nurseries and farmers' fields at Nyorigu. There was no blast at. Manga, Navrongo, Tono, Sandema, ...

  8. Blast Impact Prediction Studies at Ghana Manganese Company ...

    African Journals Online (AJOL)

    Mining of the pits involve both free digging and drilling and blasting of the overburden and the fresh competent rocks respectively. To conduct safe blasting operations in the Pit C North, studies were undertaken to assess the environmental impacts of blast associated with ground vibration, air blast and fly rock at 400 m from ...

  9. Extreme value distributions

    CERN Document Server

    Ahsanullah, Mohammad

    2016-01-01

    The aim of the book is to give a through account of the basic theory of extreme value distributions. The book cover a wide range of materials available to date. The central ideas and results of extreme value distributions are presented. The book rwill be useful o applied statisticians as well statisticians interrested to work in the area of extreme value distributions.vmonograph presents the central ideas and results of extreme value distributions.The monograph gives self-contained of theory and applications of extreme value distributions.

  10. Underbody Blast Models of TBI Caused by Hyper-Acceleration and Secondary Head Impact

    Science.gov (United States)

    2015-02-01

    in additional experiments where the top of the head is allowed to strike the surface of the cylinder ( cockpit ), which models a combined insult...the bottom of the lower plate that would give a peak acceleration of the top hull of 2800G in the absence of the compressible cylinders. As shown in...acceleration experienced by a blast loaded vehicle. To do these tests we used two round plates and kept the distance between them constant. The

  11. A multiphysics-viscoplastic cap model for simulating blast response of cemented tailings backfill

    Directory of Open Access Journals (Sweden)

    Gongda Lu

    2017-06-01

    Full Text Available Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill, an evolutive porous medium used in underground mine cavities, very few efforts have been made to improve the knowledge on its response under sudden dynamic loading during the curing process. In fact, there is a great need for such information given that cemented backfill structures are often subjected to blast loadings due to mine exploitations. In this study, a coupled thermo-hydro-mechanical-chemical (THMC-viscoplastic cap model is developed to describe the behavior of cementing mine backfill material under blast loading. A THMC model for cemented backfill is adopted to evaluate its behavior and evolution of its properties in curing processes with coupled thermal, hydraulic, mechanical and chemical factors. Then, the model is coupled to a Perzyna type of viscoplastic model with a modified smooth surface cap envelope and a variable bulk modulus, in order to reasonably capture the nonlinear and rate-dependent behaviors of the cemented tailings backfill under blast loading. All of the parameters required for the variable-modulus viscoplastic cap model were obtained by applying the THMC model to reproducing evolution of cemented paste backfill (CPB properties in the curing process. Thus, the behavior of hydrating cemented backfill under high-rate impacts can be evaluated under any curing time of concern. The validation results of the proposed model indicate a good agreement between the experimental and the simulated results. The authors believe that the proposed model will contribute to a better understanding of the performance of hydrating cemented backfill under blasting, and also to practical risk management of backfill structures associated with such a dynamic condition.

  12. 30 CFR 56.6404 - Separation of blasting circuits from power source.

    Science.gov (United States)

    2010-07-01

    ... MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. (a... when closed to fire the blast. (b) Lead wires shall not be connected to the blasting switch until the...

  13. METHOD OF LOADING OF SURFACES OF INFLUENCE BY TEMPORARY MOVING LOAD LM1

    Directory of Open Access Journals (Sweden)

    Ilyushin Nikolay Viktorovich

    2012-10-01

    The proposed methodology represents an unambiguous solution to the problem of identification of unfavourable positions of the temporary moving load LM1 (EN 1991-2 and the extreme forces or relocations involved in this respect.

  14. A new simulation method for turbines in wake - Applied to extreme response during operation

    DEFF Research Database (Denmark)

    Thomsen, K.; Aagaard Madsen, H.

    2005-01-01

    be suitable for fatigue load simulation. For extreme response during operation the success of this simplified approach depends significantly on the physical mechanism causing the extremes. If the physical mechanism creating increased loads in wake operation is different from an increased turbulence intensity...... and load response characteristics for these loads in wake conditions in good agreement with measurements. The results are compared with the traditionally used simplified method, and this approach seems conservative for some loads, e.g. the extreme blade moments, and non-conservative for others, e...

  15. Blast-Wave Generation and Propagation in Rapidly Heated Laser-Irradiated Targets

    Science.gov (United States)

    Ivancic, S. T.; Stillman, C. R.; Nilson, P. M.; Solodov, A. A.; Froula, D. H.

    2017-10-01

    Time-resolved extreme ultraviolet (XUV) spectroscopy was used to study the creation and propagation of a >100-Mbar blast wave in a target irradiated by an intense (>1018WWcm2 cm2) laser pulse. Blast waves provide a platform to generate immense pressures in the laboratory. A temporal double flash of XUV radiation was observed when viewing the rear side of the target, which is attributed to the emergence of a blast wave following rapid heating by a fast-electron beam generated from the laser pulse. The time-history of XUV emission in the photon energy range of 50 to 200 eV was recorded with an x-ray streak camera with 7-ps temporal resolution. The heating and expansion of the target was simulated with an electron transport code coupled to 1-D radiation-hydrodynamics simulations. The temporal delay between the two flashes measured in a systematic study of target thickness and composition was found to evolve in good agreement with a Sedov-Taylor blast-wave solution. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and Department of Energy Office of Science Award Number DE-SC-0012317.

  16. Megakaryocytic blast crisis as a presenting manifestation of chronic myeloid leukemia.

    Science.gov (United States)

    Pullarkat, Sheeja T; Vardiman, James W; Slovak, Marilyn L; Rao, Dinesh S; Rao, Nagesh P; Bedell, Victoria; Said, Jonathan W

    2008-11-01

    Acute megakaryocytic leukemia is a rare form of acute myelogenous leukemia and may occur either de novo or by transformation of a preexisting myelodysplastic or myeloproliferative process including blast crisis of chronic myeloid leukemia (CML). Megakaryocytic blast crisis as the presenting manifestation of CML is extremely rare. We describe such a patient with no prior hematologic disease who presented with acute megakaryoblastic leukemia and extramedullary involvement, in whom the leukemic cells carried the BCR-ABL1 translocation as part of a complex karyotype. Using targeted sequential fluorescence in situ hybridization (T-FISH) technique, we detected two copies of BCR-ABL1 fusion gene in the leukemic blasts while the neutrophils carried a single copy of BCR-ABL1 fusion gene, thereby proving the origin of the megakaryoblastic leukemia from a previously undiagnosed CML clone. Blast crisis as a presenting manifestation of CML is rare and detecting clonal evolution of acute leukemia by specialized cytogenetic techniques may have important diagnostic and therapeutic implications.

  17. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  18. directional considerations for extreme wind climatic events in the ...

    African Journals Online (AJOL)

    Dr Obe

    ABSTRACT. This paper takes a look at the importance and role of probability concepts structural design of transmission line. The reliability of transmission structure is clearly a function of the maximum loads that may be imposed over the useful life of the structure. These loads are, more often than not, caused by the extreme ...

  19. A multiscale approach to blast neurotrauma modeling: Part I - Development of novel test devices for in vivo and in vitro blast injury models

    Directory of Open Access Journals (Sweden)

    Matthew B Panzer

    2012-03-01

    Full Text Available The loading conditions used in some current in vivo and in vitro blast-induced neurotrauma models may not be representative of real-world blast conditions. To address these limitations, we developed a compressed-gas driven shock tube with different driven lengths that can generate Friedlander-type blasts. The shock tube can generate overpressures up to 650 kPa with durations between 0.3 and 1.1 ms using compressed helium driver gas, and peak overpressures up to 450 kPa with durations between 0.6 and 3 ms using compressed nitrogen. This device is used for short duration blast overpressure loading for small animal in vivo injury models, and contrasts the more frequently used long duration/high impulse blast overpressures in the literature. We also developed a new apparatus that is used with the shock tube to recreate the in vivo intracranial overpressure response for loading in vitro culture preparations. The receiver device surrounds the culture with materials of similar impedance to facilitate the propagation of a single overpressure pulse through the tissue. This method prevents pressure waves reflecting off the tissue that can cause unrealistic deformation and injury. The receiver performance was characterized using the longest helium-driven shock tube, and produced in-fluid overpressures up to 1500 kPa at the location where a culture would be placed. This response was well correlated with the overpressure conditions from the shock tube (R2 = 0.97. Finite element models of the shock tube and receiver were developed and validated to better elucidate the mechanics of this methodology. A demonstration exposing a culture to the loading conditions created by this system suggest tissue strains less than 5% for all pressure levels simulated, which was well below functional deficit thresholds for strain rates less than 50 s-1. This novel system is not limited to a specific type of culture model and can be modified to reproduce more complex pressure

  20. A Multiscale Approach to Blast Neurotrauma Modeling: Part I - Development of Novel Test Devices for in vivo and in vitro Blast Injury Models.

    Science.gov (United States)

    Panzer, Matthew B; Matthews, Kyle A; Yu, Allen W; Morrison, Barclay; Meaney, David F; Bass, Cameron R

    2012-01-01

    The loading conditions used in some current in vivo and in vitro blast-induced neurotrauma models may not be representative of real-world blast conditions. To address these limitations, we developed a compressed-gas driven shock tube with different driven lengths that can generate Friedlander-type blasts. The shock tube can generate overpressures up to 650 kPa with durations between 0.3 and 1.1 ms using compressed helium driver gas, and peak overpressures up to 450 kPa with durations between 0.6 and 3 ms using compressed nitrogen. This device is used for short-duration blast overpressure loading for small animal in vivo injury models, and contrasts the more frequently used long duration/high impulse blast overpressures in the literature. We also developed a new apparatus that is used with the shock tube to recreate the in vivo intracranial overpressure response for loading in vitro culture preparations. The receiver device surrounds the culture with materials of similar impedance to facilitate the propagation of a single overpressure pulse through the tissue. This method prevents pressure waves reflecting off the tissue that can cause unrealistic deformation and injury. The receiver performance was characterized using the longest helium-driven shock tube, and produced in-fluid overpressures up to 1500 kPa at the location where a culture would be placed. This response was well correlated with the overpressure conditions from the shock tube (R(2) = 0.97). Finite element models of the shock tube and receiver were developed and validated to better elucidate the mechanics of this methodology. A demonstration exposing a culture to the loading conditions created by this system suggest tissue strains less than 5% for all pressure levels simulated, which was well below functional deficit thresholds for strain rates less than 50 s(-1). This novel system is not limited to a specific type of culture model and can be modified to reproduce more complex pressure

  1. A Multiscale Approach to Blast Neurotrauma Modeling: Part I – Development of Novel Test Devices for in vivo and in vitro Blast Injury Models

    Science.gov (United States)

    Panzer, Matthew B.; Matthews, Kyle A.; Yu, Allen W.; Morrison, Barclay; Meaney, David F.; Bass, Cameron R.

    2012-01-01

    The loading conditions used in some current in vivo and in vitro blast-induced neurotrauma models may not be representative of real-world blast conditions. To address these limitations, we developed a compressed-gas driven shock tube with different driven lengths that can generate Friedlander-type blasts. The shock tube can generate overpressures up to 650 kPa with durations between 0.3 and 1.1 ms using compressed helium driver gas, and peak overpressures up to 450 kPa with durations between 0.6 and 3 ms using compressed nitrogen. This device is used for short-duration blast overpressure loading for small animal in vivo injury models, and contrasts the more frequently used long duration/high impulse blast overpressures in the literature. We also developed a new apparatus that is used with the shock tube to recreate the in vivo intracranial overpressure response for loading in vitro culture preparations. The receiver device surrounds the culture with materials of similar impedance to facilitate the propagation of a single overpressure pulse through the tissue. This method prevents pressure waves reflecting off the tissue that can cause unrealistic deformation and injury. The receiver performance was characterized using the longest helium-driven shock tube, and produced in-fluid overpressures up to 1500 kPa at the location where a culture would be placed. This response was well correlated with the overpressure conditions from the shock tube (R2 = 0.97). Finite element models of the shock tube and receiver were developed and validated to better elucidate the mechanics of this methodology. A demonstration exposing a culture to the loading conditions created by this system suggest tissue strains less than 5% for all pressure levels simulated, which was well below functional deficit thresholds for strain rates less than 50 s−1. This novel system is not limited to a specific type of culture model and can be modified to reproduce more complex pressure

  2. Swift GRBs and the blast wave model

    NARCIS (Netherlands)

    Curran, P.A.; van der Horst, A.J.; Starling, R.L.C.; Wijers, R.A.M.J.

    2009-01-01

    The complex structure of the light curves of Swift GRBs has made their interpretation and that of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to constrain the blast wave parameters: electron energy distribution, p, density profile of the circumburst medium,

  3. Neuro-glial and systemic mechanisms of pathological responses in rat models of primary blast overpressure compared to "composite" blast.

    Science.gov (United States)

    Svetlov, Stanislav I; Prima, Victor; Glushakova, Olena; Svetlov, Artem; Kirk, Daniel R; Gutierrez, Hector; Serebruany, Victor L; Curley, Kenneth C; Wang, Kevin K W; Hayes, Ronald L

    2012-01-01

    A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position toward blast generated by an external shock tube. In this study, we further characterized blast producing moderate traumatic brain injury and defined "composite" blast and primary blast exposure set-ups. Schlieren optics visualized interaction between the head and a shock wave generated by external shock tube, revealing strong head acceleration upon positioning the rat on-axis with the shock tube (composite blast), but negligible skull movement upon peak overpressure exposure off-axis (primary blast). Brain injury signatures of a primary blast hitting the frontal head were assessed and compared to damage produced by composite blast. Low to negligible levels of neurodegeneration were found following primary blast compared to composite blast by silver staining. However, persistent gliosis in hippocampus and accumulation of GFAP/CNPase in circulation was detected after both primary and composite blast. Also, markers of vascular/endothelial inflammation integrin alpha/beta, soluble intercellular adhesion molecule-1, and L-selectin along with neurotrophic factor nerve growth factor-beta were increased in serum within 6 h post-blasts and persisted for 7 days thereafter. In contrast, systemic IL-1, IL-10, fractalkine, neuroendocrine peptide Orexin A, and VEGF receptor Neuropilin-2 (NRP-2) were raised predominantly after primary blast exposure. In conclusion, biomarkers of major pathological pathways were elevated at all blast set-ups. The most significant and persistent changes in neuro-glial markers were found after composite blast, while primary blast instigated prominent systemic cytokine/chemokine, Orexin A, and Neuropilin-2 release

  4. Extrapolation of extreme response for different mooring line systems of floating wave energy converters

    DEFF Research Database (Denmark)

    Ambühl, Simon; Sterndorff, Martin; Sørensen, John Dalsgaard

    2014-01-01

    Mooring systems for floating wave energy converters (WECs) are a major cost driver. Failure of mooring systems often occurs due to extreme loads. This paper introduces an extrapolation method for extreme response which accounts for the control system of a WEC that controls the loads onto the stru......Mooring systems for floating wave energy converters (WECs) are a major cost driver. Failure of mooring systems often occurs due to extreme loads. This paper introduces an extrapolation method for extreme response which accounts for the control system of a WEC that controls the loads onto...... the structure and the harvested power of the device as well as the fact that extreme loads may occur during operation and not at extreme wave states when the device is in storm protection mode. The extrapolation method is based on shortterm load time series and applied to a case study where up-scaled surge load...... for the hawser as well as at the different mooring lines. Furthermore, the extreme load impact given failure of one mooring line is assessed and compared with extreme loads given no system failure....

  5. Background to plastic media blasting

    Science.gov (United States)

    Foster, Terry

    1995-04-01

    Chemical strippers based on active phenolic components in a chlorinated solvent have been the traditional method for removing of paints and coatings from aircraft. With the recent recognition of the environmental and health concerns of chlorinated solvents and the problem disposing of phenols there have been some major developments in paint removal technology. One of the first techniques developed to replace chemical strippers and now one of the most widely used techniques for paint removal from aircraft was plastic media blasting (PMB). The PMB technique is similar to traditional grit blasting (slag, sand alumina or carborundum) techniques used on steel and other metals (based on grits) but using polymer based media that are softer and less aggressive. Plastic media are ranked by hardness and density as well as chemical composition.

  6. Chronic Traumatic Encephalopathy in Blast-Exposed Military Veterans and a Blast Neurotrauma Mouse Model

    Science.gov (United States)

    Goldstein, Lee E.; Fisher, Andrew M.; Tagge, Chad A.; Zhang, Xiao-Lei; Velisek, Libor; Sullivan, John A.; Upreti, Chirag; Kracht, Jonathan M.; Ericsson, Maria; Wojnarowicz, Mark W.; Goletiani, Cezar J.; Maglakelidze, Giorgi M.; Casey, Noel; Moncaster, Juliet A.; Minaeva, Olga; Moir, Robert D.; Nowinski, Christopher J.; Stern, Robert A.; Cantu, Robert C.; Geiling, James; Blusztajn, Jan K.; Wolozin, Benjamin L.; Ikezu, Tsuneya; Stein, Thor D.; Budson, Andrew E.; Kowall, Neil W.; Chargin, David; Sharon, Andre; Saman, Sudad; Hall, Garth F.; Moss, William C.; Cleveland, Robin O.; Tanzi, Rudolph E.; Stanton, Patric K.; McKee, Ann C.

    2013-01-01

    Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein–linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory. PMID:22593173

  7. Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model.

    Science.gov (United States)

    Goldstein, Lee E; Fisher, Andrew M; Tagge, Chad A; Zhang, Xiao-Lei; Velisek, Libor; Sullivan, John A; Upreti, Chirag; Kracht, Jonathan M; Ericsson, Maria; Wojnarowicz, Mark W; Goletiani, Cezar J; Maglakelidze, Giorgi M; Casey, Noel; Moncaster, Juliet A; Minaeva, Olga; Moir, Robert D; Nowinski, Christopher J; Stern, Robert A; Cantu, Robert C; Geiling, James; Blusztajn, Jan K; Wolozin, Benjamin L; Ikezu, Tsuneya; Stein, Thor D; Budson, Andrew E; Kowall, Neil W; Chargin, David; Sharon, Andre; Saman, Sudad; Hall, Garth F; Moss, William C; Cleveland, Robin O; Tanzi, Rudolph E; Stanton, Patric K; McKee, Ann C

    2012-05-16

    Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein-linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory.

  8. Modeling and simulation of blast-induced, early-time intracranial wave physics leading to traumatic brain injury.

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Corey C. (University of New Mexico, Albuquerque, NM); Taylor, Paul Allen

    2008-02-01

    The objective of this modeling and simulation study was to establish the role of stress wave interactions in the genesis of traumatic brain injury (TBI) from exposure to explosive blast. A high resolution (1 mm{sup 3} voxels), 5 material model of the human head was created by segmentation of color cryosections from the Visible Human Female dataset. Tissue material properties were assigned from literature values. The model was inserted into the shock physics wave code, CTH, and subjected to a simulated blast wave of 1.3 MPa (13 bars) peak pressure from anterior, posterior and lateral directions. Three dimensional plots of maximum pressure, volumetric tension, and deviatoric (shear) stress demonstrated significant differences related to the incident blast geometry. In particular, the calculations revealed focal brain regions of elevated pressure and deviatoric (shear) stress within the first 2 milliseconds of blast exposure. Calculated maximum levels of 15 KPa deviatoric, 3.3 MPa pressure, and 0.8 MPa volumetric tension were observed before the onset of significant head accelerations. Over a 2 msec time course, the head model moved only 1 mm in response to the blast loading. Doubling the blast strength changed the resulting intracranial stress magnitudes but not their distribution. We conclude that stress localization, due to early time wave interactions, may contribute to the development of multifocal axonal injury underlying TBI. We propose that a contribution to traumatic brain injury from blast exposure, and most likely blunt impact, can occur on a time scale shorter than previous model predictions and before the onset of linear or rotational accelerations traditionally associated with the development of TBI.

  9. Classifying Returns as Extreme

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2014-01-01

    I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme...... that classifies extreme returns for several markets jointly. The new classification scheme holds about the same information as the old one, while demanding a shorter sample period. The new classification scheme is useful....

  10. The Effect on the Propagation of Blast Pulses of Dry and Dampened Granular Media

    Science.gov (United States)

    Proud, William; Badham, Henry; Chalmers, Max; Nguyen, Thuy-Tien

    2015-06-01

    The propagation of stress through granular and dampened granular material has been reported in previous papers. With increasing presence of liquid in granular beds the transmission of blast and pressure pulse changes from one of percolation through the bed pores to one of wave transmission through the granules of the bed. It has been shown that limited amounts liquid can retard pressurisation within confined blast-loaded beds by approximately an order of magnitude. This study presents data on percolation through dry and dampened granular beds using a shock tube as the pressure driver. In this scenario the effect of the bed on initial pressure pulse is studied in greater detail. The effect of particle shape and size was investigated using angular grains of quartz sand as well as smooth glass microspheres. The effect of addition of liquids is presented. The pressure range studied is in the range associated with blast injury and with far field effects produced by explosive devices. The Institute of Shock Physics acknowledges the support of AWE, Aldermaston, UK and Imperial College London. The Centre for Blast Injury Studies acknowledges the support of the Royal British Legion and Imperial College London.

  11. Development of a multimodal blast sensor for measurement of head impact and over-pressurization exposure.

    Science.gov (United States)

    Chu, Jeffrey J; Beckwith, Jonathan G; Leonard, Daniel S; Paye, Corey M; Greenwald, Richard M

    2012-01-01

    It is estimated that 10-20% of United States soldiers returning from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) have suffered at least one instance of blast-induced traumatic brain injury (bTBI) with many reporting persistent symptomology and long-term effects. This variation in blast response may be related to the complexity of blast waves and the many mechanisms of injury, including over-pressurization due to the shock wave and potential for blunt impacts to the head from shrapnel or from other indirect impacts (e.g., building, ground, and vehicle). To help differentiate the effects of primary, secondary, and tertiary effects of blast, a custom sensor was developed to simultaneously measure over-pressurization and blunt impact. Moreover, a custom, complementary filter was designed to differentiate the measurements of blunt (low-frequency bandwidth) from over-pressurization (high-frequency bandwidth). The custom sensor was evaluated in the laboratory using a shock tube to simulate shock waves and a drop fixture to simulate head impacts. Both bare sensors and sensor embedded within an ACH helmet coupon were compared to laboratory reference transducers under multiple loading conditions (n = 5) and trials at each condition (n = 3). For all comparative measures, peak magnitude, peak impulse, and cross-correlation measures, R (2) values, were greater than 0.900 indicating excellent agreement of peak measurements and time-series comparisons with laboratory measures.

  12. Interspecies Scaling in Blast Neurotrauma

    Science.gov (United States)

    2015-08-27

    potential for human injury (Mertz 1985). The dummy has also been utilized for biomechanics research in sports injury (Pellman et al. 2003) and military...of existing experimental data was used. This dissertation makes major contributions to the field of injury biomechanics and blast injury research...contributions and conclusions of this dissertation serve to inform the injury biomechanics field and to improve future research efforts. The consideration by

  13. Controlled Blasting with Demolition Agent

    OpenAIRE

    Dambov, Risto; Stefanovska Karanakova, Radmila; Dambov, Ilija

    2009-01-01

    Over the last decades of last century and this years the interest in using nonexplosive demolition has increased again. Several companies started producing various agents with various names and similar characteristics, but with the same conditions of use. Unlike demolition by blasting, this method is environmentally friendly. The operation takes place quietly, with no seismic affects, dust, gases and no flying rocks. Rock cutting is done as needed and in the desired scale, with-out affecti...

  14. EXTREME AND TERMINAL STATES

    Directory of Open Access Journals (Sweden)

    P.F. Litvitsky

    2010-01-01

    Full Text Available Author brings modern conception of extreme and terminal states, their types, likenesses and differences, etiology, key common chains of pathogenesis, principles and methods of their treatment. Pathophysiological data on one of extreme states — collapse — is described in details. Next publications will present the data on shock and coma.Key words: extreme and terminal states, vicious circle of pathogenesis, extreme regulation, principles of treatment.(Voprosy sovremennoi pediatrii — Current Pediatrics. – 2010;9(3:74-80

  15. Brain injury risk from primary blast.

    Science.gov (United States)

    Rafaels, Karin A; Bass, Cameron R Dale; Panzer, Matthew B; Salzar, Robert S; Woods, William A; Feldman, Sanford H; Walilko, Tim; Kent, Richard W; Capehart, Bruce P; Foster, Jonathan B; Derkunt, Burcu; Toman, Amanda

    2012-10-01

    Military service members are often exposed to at least one explosive event, and many blast-exposed veterans present with symptoms of traumatic brain injury. However, there is little information on the intensity and duration of blast necessary to cause brain injury. Varying intensity shock tube blasts were focused on the head of anesthetized ferrets, whose thorax and abdomen were protected. Injury evaluations included physiologic consequences, gross necropsy, and histologic diagnosis. The resulting apnea, meningeal bleeding, and fatality were analyzed using logistic regressions to determine injury risk functions. Increasing severity of blast exposure demonstrated increasing apnea immediately after the blast. Gross necropsy revealed hemorrhages, frequently near the brain stem, at the highest blast intensities. Apnea, bleeding, and fatality risk functions from blast exposure to the head were determined for peak overpressure and positive-phase duration. The 50% risk of apnea and moderate hemorrhage were similar, whereas the 50% risk of mild hemorrhage was independent of duration and required lower overpressures (144 kPa). Another fatality risk function was determined with existing data for scaled positive-phase durations from 1 millisecond to 20 milliseconds. The first primary blast brain injury risk assessments for mild and moderate/severe injuries in a gyrencephalic animal model were determined. The blast level needed to cause a mild/moderate brain injury may be similar to or less than that needed for pulmonary injury. The risk functions can be used in future research for blast brain injury by providing realistic injury risks to guide the design of protection or evaluate injury.

  16. DeRisk - Accurate prediction of ULS wave loads. Outlook and first results

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Dixen, Martin; Ghadirian, Amin

    2016-01-01

    Loads from extreme waves can be dimensioning for the substructures of offshore wind turbines. The DeRisk project (2015-2019) aims at an improved load evaluation procedure for extreme waves through application of advanced wave models, laboratory tests of load effects, development of hydrodynamic l...

  17. PROGRESS IN THERMO-ABRASIVE BLASTING SYSTEMS

    Directory of Open Access Journals (Sweden)

    I.A. Gorlach

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Quality of surface preparation of components and structures for further painting and/or coating is important in many fields of engineering. One of the most widely used methods of surface preparation is abrasive blasting. In the last few years, a new method for surface preparation has evolved, namely thermo-abrasive blasting. This technique utilises a high enthalpy thermal jet, generated by the thermo-abrasive blasting gun, to propel abrasive particles. Thermo-abrasive blasting has a number of advantages over conventional abrasive blasting, which were assessed during trials. This paper describes a progress in the applications of thermo-abrasive blasting as well as future potentials for South African industry. The performance data and economic comparison of conventional and thermo-abrasive blasting are also presented in this paper.

    AFRIKAANSE OPSOMMING: Die gehalte van voorbereiding van komponent- en struktuuroppervlaktes is oral belangrik in ingenieurswesetoepassings. Wat vrywel tot die hede dikwels gebruik was, is straalskuring. Onlangs het 'n nuwe metode tot stand gekom naamlik termostraalskuring. Die metode maak gebruik van 'n hoë entalpie termostaat om skuurmiddel aan te dryf. Die nuwe metode besit sekere voordele in vergelyking met tradisionele straalskuring. Praktykbevestiging is hiervan met toetse verkry. Hierdie stuk bespreek ook die praktyktoepassings van termostraalskuring en die gepaardgaande voordele vir die Suid-Afrikaanse nywerheid. Toepassingsdata en ekomiese vergelyking van konvensionele- en termostraalskuring word ook behandel.

  18. LTC vacuum blasting machine (concrete): Baseline report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-31

    The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure during maintenance activities was minimal, but due to mechanical difficulties dust monitoring could not be conducted during operation. Noise exposure was significant. Further testing for each of these exposures is recommended because of the outdoor environment where the testing demonstration took place. This may cause the results to be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed environment. In addition, other safety and health issues found were ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, and arm-hand vibration.

  19. Blast investigation by fast multispectral radiometric analysis

    Science.gov (United States)

    Devir, A. D.; Bushlin, Y.; Mendelewicz, I.; Lessin, A. B.; Engel, M.

    2011-06-01

    Knowledge regarding the processes involved in blasts and detonations is required in various applications, e.g. missile interception, blasts of high-explosive materials, final ballistics and IED identification. Blasts release large amount of energy in short time duration. Some part of this energy is released as intense radiation in the optical spectral bands. This paper proposes to measure the blast radiation by a fast multispectral radiometer. The measurement is made, simultaneously, in appropriately chosen spectral bands. These spectral bands provide extensive information on the physical and chemical processes that govern the blast through the time-dependence of the molecular and aerosol contributions to the detonation products. Multi-spectral blast measurements are performed in the visible, SWIR and MWIR spectral bands. Analysis of the cross-correlation between the measured multi-spectral signals gives the time dependence of the temperature, aerosol and gas composition of the blast. Farther analysis of the development of these quantities in time may indicate on the order of the detonation and amount and type of explosive materials. Examples of analysis of measured explosions are presented to demonstrate the power of the suggested fast multispectral radiometric analysis approach.

  20. BlastGraph: a comparative genomics tool based on BLAST and graph algorithms.

    Science.gov (United States)

    Ye, Yanbo; Wei, Bo; Wen, Lei; Rayner, Simon

    2013-12-15

    BlastGraph is an interactive Java program for comparative genome analysis based on Basic Local Alignment Search Tool (BLAST), graph clustering and data visualization. The software generates clusters of sequences of multiple genomes from all-to-all BLAST results and visualizes the results in graph plots together with related information such as sequence features, gene conservation and similarity relationships. Pruning algorithms are used to reduce results to more meaningful subclusters. Subsequent analyses can then be conducted based on the predicted clusters, including gene content, genome phylogenetics and gene gain and loss. https://github.com/bigwiv/BlastGraph.

  1. Blast Injuries: From Improvised Explosive Device Blasts to the Boston Marathon Bombing.

    Science.gov (United States)

    Singh, Ajay K; Ditkofsky, Noah G; York, John D; Abujudeh, Hani H; Avery, Laura A; Brunner, John F; Sodickson, Aaron D; Lev, Michael H

    2016-01-01

    Although most trauma centers have experience with the imaging and management of gunshot wounds, in most regions blast wounds such as the ones encountered in terrorist attacks with the use of improvised explosive devices (IEDs) are infrequently encountered outside the battlefield. As global terrorism becomes a greater concern, it is important that radiologists, particularly those working in urban trauma centers, be aware of the mechanisms of injury and the spectrum of primary, secondary, tertiary, and quaternary blast injury patterns. Primary blast injuries are caused by barotrauma from the initial increased pressure of the explosive detonation and the rarefaction of the atmosphere immediately afterward. Secondary blast injuries are caused by debris carried by the blast wind and most often result in penetrating trauma from small shrapnel. Tertiary blast injuries are caused by the physical displacement of the victim and the wide variety of blunt or penetrating trauma sustained as a result of the patient impacting immovable objects such as surrounding cars, walls, or fences. Quaternary blast injuries include all other injuries, such as burns, crush injuries, and inhalational injuries. Radiography is considered the initial imaging modality for assessment of shrapnel and fractures. Computed tomography is the optimal test to assess penetrating chest, abdominal, and head trauma. The mechanism of blast injuries and the imaging experience of the victims of the Boston Marathon bombing are detailed, as well as musculoskeletal, neurologic, gastrointestinal, and pulmonary injury patterns from blast injuries. ©RSNA, 2016.

  2. Concrete structures under impact loading: general aspects

    Directory of Open Access Journals (Sweden)

    Cornelia Baeră

    2016-09-01

    Full Text Available Dynamic loading conditions distress the structural integrity of a structure differently than the static ones. Such actions transfer high rate strains and instant energy waves to the structure, inducing the possibility of imminent collapse and casualties as a direct consequence. In the latest years, considering the dramatic increase of terrorist threats and global warming, the structural safety criteria imply more than ever the need to withstand this kind of loading (e.g., missiles and blast, projectiles, strong winds, tornados and earthquakes in addition to the static ones. The aim of this paper is to provide a general overview with regard to impact loading in terms of defining the phenomenon from physical and mechanical perspective, its complex local or global effect on the targeted structure, relevant material characteristics, main research approaches, namely theoretical studies and experimental procedures developed for improving the predictability of the dynamic loads and their effects. New directions in developing superior cementitious composites, with better characteristics in terms of dynamic loading performance are also emphasized.

  3. Durability of geothermal grouting materials considering extreme loads

    OpenAIRE

    Indacoechea Vega, Irune; Pascual Muñoz, Pablo; Castro Fresno, Daniel; Zamora-Barraza, D

    2018-01-01

    The concern about the massive use of the non-renewable and very limited fossil fuels together with the well-known effects of the global warming makes it more necessary the efficient use of the current forms of renewable energy generation. Because of the crucial role played by the grouting materials in the Ground Source Heat Pumps (GSHP), a proper selection of these elements should be made based on a deep knowledge of their performance. In this paper, thermal conductivity, mechanical strength ...

  4. Mechanical load on the upper extremity during wheelchair activities

    NARCIS (Netherlands)

    Van Drongelen, Stefan; Van der Woude, Lucas H; Janssen, Thomas W; Angenot, Edmond L; Chadwick, Edward K; Veeger, DirkJan (H. E. J.)

    OBJECTIVE: To determine the net moments on the glenohumeral joint and elbow joint during wheelchair activities. DESIGN: Kinematics and external forces were measured during wheelchair activities of daily living (level propulsion, riding on a slope, weight-relief lifting, reaching, negotiating a curb)

  5. Mechanical load on the upper extremity during wheelchair activities

    NARCIS (Netherlands)

    van Drongelen, S.; van der Woude, L.H.V.; Janssen, T.W.J.; Angenot, E.D.L.; Chadwick, E.K.J.; Veeger, H.E.J.

    2005-01-01

    Objective: To determine the net moments on the glenohumeral joint and elbow joint during wheelchair activities. Design: Kinematics and external forces were measured during wheelchair activities of daily living (level propulsion, riding on a slope, weight-relief lifting, reaching, negotiating a curb)

  6. Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads

    Energy Technology Data Exchange (ETDEWEB)

    Gerstl, S.A.W.; Zardecki, A.

    1981-08-01

    The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10/sup 1/ g is sufficient to reduce photosynthesis to 10/sup -3/ of normal. We also infer from this result tha the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al. is thus shown to be a possible extinction mechanism, even with smaller size asteroids of comets than previously estimated.

  7. Experimental investigation of ultimate loads

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, S.M.; Larsen, G.C.; Antoniou, I.; Lind, S.O.; Courtney, M. [Risoe National Lab., Wind Energy and Atmospheric Physics, Roskilde (Denmark)

    1999-03-01

    Verification of the structural integrity of a wind turbine involves analysis of fatigue loading as well as ultimate loading. With the trend of persistently growing turbines, the ultimate loading seems to become relatively more important. For wind turbines designed according to the wind conditions prescribed in the IEC-61400 code, the ultimate load is often identified as the leading load parameter. Exemplified by the use of an extensive measurement campaign a procedure for evaluation of the extreme flap-wise bending moments, occurring during normal operating of a wind turbine, is presented. The structural measurements are made on a NEG Micon 650 kW wind turbine erected at a complex high wind site in Oak Creek, California. The turbine is located on the top of a ridge. The prevailing wind direction is perpendicular to the ridge, and the annual mean wind speed is 9.5 m/s. The associated wind field measurement, are taken from two instrumented masts erected less than one rotor diameter in front of the turbine in direction of the prevailing wind direction. Both masts are instrumented at different heights in order to gain insight of the 3D-wind speed structure over the entire rotor plane. Extreme distributions, associated with a recurrence period of 10 minutes, conditioned on the mean wind speed and the turbulence intensity are derived. Combined with the wind climate model proposed in the IEC standard, these distributions are used to predict extreme distributions with recurrence periods equal to one and fifty years, respectively. The synthesis of the conditioned PDF`s and the wind climate model is performed by means of Monte Carlo simulation. (au)

  8. Improved mine blast algorithm for optimal cost design of water distribution systems

    Science.gov (United States)

    Sadollah, Ali; Guen Yoo, Do; Kim, Joong Hoon

    2015-12-01

    The design of water distribution systems is a large class of combinatorial, nonlinear optimization problems with complex constraints such as conservation of mass and energy equations. Since feasible solutions are often extremely complex, traditional optimization techniques are insufficient. Recently, metaheuristic algorithms have been applied to this class of problems because they are highly efficient. In this article, a recently developed optimizer called the mine blast algorithm (MBA) is considered. The MBA is improved and coupled with the hydraulic simulator EPANET to find the optimal cost design for water distribution systems. The performance of the improved mine blast algorithm (IMBA) is demonstrated using the well-known Hanoi, New York tunnels and Balerma benchmark networks. Optimization results obtained using IMBA are compared to those using MBA and other optimizers in terms of their minimum construction costs and convergence rates. For the complex Balerma network, IMBA offers the cheapest network design compared to other optimization algorithms.

  9. Fine fragmentation distribution from structural reactive material casings under explosive loading

    Science.gov (United States)

    Wilson, William H.; Zhang, Fan; Kim, Kibong

    2017-01-01

    For a full understanding of the contribution to the primary blast wave, the collection and analysis of fragment distribution down to 37 µm from a 3.3 cm I.D., thick structural reactive material (SRM) casing under explosive loading are investigated in a 2.1 m3 closed cylindrical chamber packed with artificially-made pure snow. The fragmentation distributions obtained from three types of SRM casings show that a 75-80% mass fraction is achievable for fragments in a range below 125 µm from specified SRM, consistent with its significantly more enhanced primary blast behaviour.

  10. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural wave (Conference Presentation)

    Science.gov (United States)

    Chen, Yangyang; Huang, Guoliang

    2017-04-01

    A great deal of research has been devoted to controlling the dynamic behaviors of phononic crystals and metamaterials by directly tuning the frequency regions and/or widths of their inherent band gaps. Here, we present a novel approach to achieve extremely broadband flexural wave/vibration attenuation based on tunable local resonators made of piezoelectric stacks shunted by hybrid negative capacitance and negative inductance circuits with proof masses attached on a host beam. First, wave dispersion relations of the adaptive metamaterial beam are calculated analytically by using the transfer matrix method. The unique modulus tuning properties induced by the hybrid shunting circuits are then characterized conceptually, from which the frequency dependent modulus tuning curves of the piezoelectric stack located within wave attenuation frequency regions are quantitatively identified. As an example, a flexural wave high-pass band filter with a wave attenuation region from 0 to 23.0 kHz is demonstrated analytically and numerically by using the hybrid shunting circuit, in which the two electric components are connected in series. By changing the connection pattern to be parallel, another super wide wave attenuation region from 13.5 to 73.0 kHz is demonstrated to function as a low-pass filter at a subwavelength scale. The proposed adaptive metamaterial possesses a super wide band gap created both naturally and artificially. Therefore, it can be used for the transient wave mitigation at extremely broadband frequencies such as blast or impact loadings. We envision that the proposed design and approach can open many possibilities in broadband vibration and wave control.

  11. Integrated Experimental Platforms to Study Blast Injuries: a Bottom-Up Approach

    Science.gov (United States)

    Bo, Chiara

    2013-06-01

    Developing a cellular and molecular understanding of the nature of traumatic and post-traumatic effects of blast events on live biological samples is critical for improving clinical outcomes.1 To investigate the consequences of pressure waves upon cellular structures and the underlying physiological and biochemical changes, we are using an integrated approach to study the material and biological properties of cells, tissues and organs when subjected to extreme conditions. In particular we have developed a confined Split Hopkinson Pressure Bar (SHPB) system, which allows us to subject cells in suspension or in a monolayer to compression waves of the order of few MPa and duration of hundreds of microseconds.2 The chamber design also enables recovery of the biological samples for cellular and molecular analysis. Specifically, cell survivability, viability, proliferation and morphological changes are investigated post compression for different cell populations. The SHPB platform, coupled with Quasi-Static experiments, is also used to determine stress-strain curves of soft biological tissues under compression at low, medium and high strain rates. Samples are also examined using histological techniques to study macro- and microscopical changes induced by compression waves. Finally, a shock tube has been developed to replicate primary blast damage on organs (i.e. mice lungs) and cell monolayers by generating single or multiple air blast of the order of kPa and few milliseconds duration. This platform allows us to visualize post-traumatic morphological changes at the cellular level as a function of the stimulus pressure and duration as well as biomarker signatures of blast injuries. Adapting and integrating a variety of approaches with different experimental platforms allows us to sample a vast pressure-time space in terms of biological and structural damage that mimic blast injuries and also to determine which physical parameters (peak pressure, stimulus duration, impulse

  12. Dry media blasting with wheat starch

    Science.gov (United States)

    Foster, Terry

    1995-04-01

    The brand name TECHNOSTRIP covers several types of installations and facilities. These were developed mainly to meet the requirements of customers in the aeronautic field. The range of products includes: complete self-supporting and semi-automated system for aircraft stripping; large-size blasting booth for semi-automatic stripping; manual blasting booth; and sealed and portable manual stripping head. Wheat starch media was developed for particle blasting stripping and is used in TECHNOSTRIP. This paper reviews its origins and use as well as use of automated facilities, reliability, effects on materials, effects on environment, and utilization examples.

  13. Final Report of the Lower Extremity Assessment Program (LEAP 99-2). Volume 2

    Science.gov (United States)

    2000-08-01

    affected by current footwear . The Wellco OB demonstrated a trend of marginal improvement in protection against the smallest mine tested (M- 14). This...milliseconds with a possible trend towards slower subsequent decay of the measured load with the blast attenuating footwear . Disruption of the combat...that currently available landmine protective footwear does not prevent severe injury. This footwear potentially reduces injury severity against some

  14. Flooding hazards from sea extremes and subsidence

    DEFF Research Database (Denmark)

    Sørensen, Carlo; Vognsen, Karsten; Broge, Niels

    2015-01-01

    If we do not understand the effects of climate change and sea level rise (SLR) we cannot live in low-lying coastal areas in the future. Permanent inundation may become a prevalent issue but more often floods related to extreme events have the largest damage potential, and the management of flooding...... hazards needs to integrate the water loading from various sources. Furthermore, local subsidence must be accounted for in order to evaluate current and future flooding hazards and management options. We present the methodology (Figure) and preliminary results from the research project “Coastal Flooding...... Hazards due to Storm Surges and Subsidence” (2014-2017) with the objective to develop and test a practice oriented methodology for combining extreme water level statistics and land movement in coastal flooding hazard mapping and in climate change adaptation schemes in Denmark. From extreme value analysis...

  15. BLAST-EXPLORER helps you building datasets for phylogenetic analysis

    Directory of Open Access Journals (Sweden)

    Claverie Jean-Michel

    2010-01-01

    Full Text Available Abstract Background The right sampling of homologous sequences for phylogenetic or molecular evolution analyses is a crucial step, the quality of which can have a significant impact on the final interpretation of the study. There is no single way for constructing datasets suitable for phylogenetic analysis, because this task intimately depends on the scientific question we want to address, Moreover, database mining softwares such as BLAST which are routinely used for searching homologous sequences are not specifically optimized for this task. Results To fill this gap, we designed BLAST-Explorer, an original and friendly web-based application that combines a BLAST search with a suite of tools that allows interactive, phylogenetic-oriented exploration of the BLAST results and flexible selection of homologous sequences among the BLAST hits. Once the selection of the BLAST hits is done using BLAST-Explorer, the corresponding sequence can be imported locally for external analysis or passed to the phylogenetic tree reconstruction pipelines available on the Phylogeny.fr platform. Conclusions BLAST-Explorer provides a simple, intuitive and interactive graphical representation of the BLAST results and allows selection and retrieving of the BLAST hit sequences based a wide range of criterions. Although BLAST-Explorer primarily aims at helping the construction of sequence datasets for further phylogenetic study, it can also be used as a standard BLAST server with enriched output. BLAST-Explorer is available at http://www.phylogeny.fr

  16. Analysis of extreme events

    CSIR Research Space (South Africa)

    Khuluse, S

    2009-04-01

    Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

  17. Extreme bosonic linear channels

    Science.gov (United States)

    Holevo, A. S.

    2013-02-01

    The set of all channels with a fixed input and output is convex. We first give a convenient formulation of the necessary and sufficient condition for a channel to be an extreme point of this set in terms of the complementary channel, a notion of great importance in quantum information theory. This formulation is based on the general approach to extremality of completely positive maps in an operator algebra in the spirit of Arveson. We then use this formulation to prove our main result: under certain nondegeneracy conditions, environmental purity is necessary and sufficient for the extremality of a bosonic linear (quasifree) channel. It hence follows that a Gaussian channel between finite-mode bosonic systems is extreme if and only if it has minimum noise.

  18. Extreme environments and exobiology

    Science.gov (United States)

    Friedmann, E. I.

    1993-01-01

    Ecological research on extreme environments can be applied to exobiological problems such as the question of life on Mars. If life forms (fossil or extant) are found on Mars, their study will help to solve fundamental questions about the nature of life on Earth. Extreme environments that are beyond the range of adaptability of their inhabitants are defined as "absolute extreme". Such environments can serve as terrestrial models for the last stages of life in the history of Mars, when the surface cooled down and atmosphere and water disappeared. The cryptoendolithic microbial community in porous rocks of the Ross Desert in Antarctica and the microbial mats at the bottom of frozen Antarctic lakes are such examples. The microbial communities of Siberian permafrost show that, in frozen but stable communities, long-term survival is possible. In the context of terraforming Mars, selected microorganisms isolated from absolute extreme environments are considered for use in creation of a biological carbon cycle.

  19. The multi-modal responses of a physical head model subjected to various blast exposure conditions

    Science.gov (United States)

    Ouellet, S.; Phillippens, M.

    2017-11-01

    structure, and direction of propagation. Convincing evidence of stresses generated from local skull deformation is presented along with evidence of stress transmission through relative brain-to-skull motion. These findings suggest that research aimed at defining exposure thresholds should not focus on a single stress transmission mechanism or use experimental designs unrepresentative of realistic blast loading conditions that may favour a given mechanism over another.

  20. Explosion/Blast Dynamics for Constellation Launch Vehicles Assessment

    Science.gov (United States)

    Baer, Mel; Crawford, Dave; Hickox, Charles; Kipp, Marlin; Hertel, Gene; Morgan, Hal; Ratzel, Arthur; Cragg, Clinton H.

    2009-01-01

    An assessment methodology is developed to guide quantitative predictions of adverse physical environments and the subsequent effects on the Ares-1 crew launch vehicle associated with the loss of containment of cryogenic liquid propellants from the upper stage during ascent. Development of the methodology is led by a team at Sandia National Laboratories (SNL) with guidance and support from a number of National Aeronautics and Space Administration (NASA) personnel. The methodology is based on the current Ares-1 design and feasible accident scenarios. These scenarios address containment failure from debris impact or structural response to pressure or blast loading from an external source. Once containment is breached, the envisioned assessment methodology includes predictions for the sequence of physical processes stemming from cryogenic tank failure. The investigative techniques, analysis paths, and numerical simulations that comprise the proposed methodology are summarized and appropriate simulation software is identified in this report.

  1. High prevalence of chronic pituitary and target-organ hormone abnormalities after blast-related mild traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Charles W. Wilkinson

    2012-02-01

    Full Text Available Studies of traumatic brain injury from all causes have found evidence of chronic hypopituitarism, defined by deficient production of one or more pituitary hormones at least one year after injury, in 25-50% of cases. Most studies found the occurrence of posttraumatic hypopituitarism (PTHP to be unrelated to injury severity. Growth hormone deficiency (GHD and hypogonadism were reported most frequently. Hypopituitarism, and in particular adult GHD, is associated with symptoms that resemble those of PTSD, including fatigue, anxiety, depression, irritability, insomnia, sexual dysfunction, cognitive deficiencies, and decreased quality of life. However, the prevalence of PTHP after blast-related mild TBI (mTBI, an extremely common injury in modern military operations, has not been characterized. We measured concentrations of 12 pituitary and target-organ hormones in two groups of male US Veterans of combat in Iraq or Afghanistan. One group consisted of participants with blast-related mTBI whose last blast exposure was at least one year prior to the study. The other consisted of Veterans with similar military deployment histories but without blast exposure. Eleven of 26, or 42% of participants with blast concussions were found to have abnormal hormone levels in one or more pituitary axes, a prevalence similar to that found in other forms of TBI. Five members of the mTBI group were found with markedly low age-adjusted insulin-like growth factor-I (IGF-I levels indicative of probable GHD, and three had testosterone and gonadotropin concentrations consistent with hypogonadism. If symptoms characteristic of both PTHP and PTSD can be linked to pituitary dysfunction, they may be amenable to treatment with hormone replacement. Routine screening for chronic hypopituitarism after blast concussion shows promise for appropriately directing diagnostic and therapeutic decisions that otherwise may remain unconsidered and for markedly facilitating recovery and

  2. Design of SC walls and slabs for impulsive loading

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Amit H. [Purdue Univ., West Lafayette, IN (United States)

    2015-11-11

    Reinforced concrete (RC) structures have historically been the preferred choice for blast resistant structures because of their mass and the ductility provided by steel reinforcement. Steel-plate composite (SC) walls are a viable alternative to RC for protecting the infrastructure against explosive threats. SC structures consist of two steel faceplates with a plain concrete core between them. The steel faceplates are anchored to the concrete using stud anchors and connected to each other using tie bars. SC structures provide mass from the concrete infill and ductility from the continuous external steel faceplates. This dissertation presents findings and recommendations from experimental and analytical investigations of the performance of SC walls subjected to far-field blast loads.

  3. Fast multispectral radiometric method and instruments for analysis of blast

    Science.gov (United States)

    Sabati, T. Y.; Devir, A. D.; Lessin, A. B.; Engel, M.; Bushlin, Y.

    2010-10-01

    Blasts and detonations release large amount of energy in short time duration. Some of this energy is released in the form of intense radiation in the whole optical spectrum. In most cases, the study of blasts is mainly based on cameras that document the event in the visible range at very high frame rates. We propose to complement this mode of blast analysis with a fast measurement of the radiation emitted by the blast at different spectral bands simultaneously. A fast multispectral radiometer that operates in the proper spectral bands provides extensive information on the physical processes that govern the blast. This information includes the time dependence of the temperature, aerosol and gas composition of the blast, as well as minute changes in the expansion of the blast - changes that may indicate the order of the detonation. This paper presents the new methodology and instrumentation of fast multispectral blast radiometry and shows analysis of measured explosions that demonstrate the power of this methodology.

  4. Experimental Measures of Blast and Acoustic Trauma in Marine Mammals

    National Research Council Canada - National Science Library

    Ketten, Darlene R

    2004-01-01

    .... To determine onset of damage zones for blast trauma in marine mammals, fresh post-mortem specimens were implanted with pressure gages, CT scanned, and exposed to underwater blast pressures of 10-300 psi...

  5. Blast effects physical properties of shock waves

    CERN Document Server

    2018-01-01

    This book compiles a variety of experimental data on blast waves. The book begins with an introductory chapter and proceeds to the topic of blast wave phenomenology, with a discussion Rankine-Hugoniot equations and the Friedlander equation, used to describe the pressure-time history of a blast wave. Additional topics include arrival time measurement, the initiation of detonation by exploding wires, a discussion of TNT equivalency, and small scale experiments. Gaseous and high explosive detonations are covered as well. The topics and experiments covered were chosen based on the comparison of used scale sizes, from small to large. Each characteristic parameter of blast waves is analyzed and expressed versus scaled distance in terms of energy and mass. Finally, the appendix compiles a number of polynomial laws that will prove indispensable for engineers and researchers.

  6. Blast furnace supervision and control system

    Energy Technology Data Exchange (ETDEWEB)

    Remorino, M.; Lingiardi, O.; Zecchi, M. [Siderar S.A.I.C./Ingdesi, San Nicolas (Argentina)

    1997-12-31

    On December 1992, a group of companies headed by Techint, took over Somisa, the state-owned integrated steel plant located at San Nicolas, Province of Buenos Aires, Argentina, culminating an ambitious government privatization scheme. The blast furnace 2 went into a full reconstruction and relining in January 1995. After a 140 MU$ investment the new blast furnace 2 was started in September 1995. After more than one year of operation of the blast furnace the system has proven itself useful and reliable. The main reasons for the success of the system are: same use interface for all blast furnace areas -- operation, process, maintenance and management, (full horizontal and vertical integration); and full accessibility to all information and process tools though some restrictions apply to field commands (people empowerment). The paper describes the central system.

  7. Engineering and Design: Underwater Blast Monitoring

    National Research Council Canada - National Science Library

    McPherson, John

    1991-01-01

    .... The purpose of this ETL is to assist USACE Commands in the intelligent use of underwater blast monitoring to prevent damage or injury to nearby structures, equipment, or aquatic life from water shock effects...

  8. Basic Local Alignment Search Tool (BLAST)

    Data.gov (United States)

    U.S. Department of Health & Human Services — BLAST finds regions of similarity between biological sequences. The program compares nucleotide or protein sequences to sequence databases and calculates the...

  9. Prevention of Blast-Related Injuries

    Science.gov (United States)

    2013-07-01

    intraocular pressure to a point that the sclera tears . The documented use of eye protection was only 24% among all 523 ocular injury cases (Weichel...involves the following subtasks: (a) Literature review of blast induced ocular injury and TBI (b) Development and integration of the eye model...with the human head model (c) Validation of the eye model against cadaveric impact test data (a) Literature review of blast induced ocular injury

  10. Localized coating removal using plastic media blasting

    Science.gov (United States)

    Novak, Howard L.; Wyckoff, Michael G.; Zook, Lee M.

    1988-01-01

    Steps taken to qualify the use of plastic media blasting for safely and effectively removing paint and other coatings from solid rocket booster aluminum structures are described. As a result of the effort, an improvement was made in the design of surface finishing equipment for processing flight hardware, in addition to a potentially patentable idea on improved plastic media composition. The general arrangement of the blast equipment and the nozzle configuration are presented.

  11. Prevention of Blast-Related Injuries

    Science.gov (United States)

    2016-07-01

    but show persistent symptoms such as fatigue , headaches, and delayed recall of memory.10-12 It is still not clear how a blast wave interacts with the...anesthesia (ketamine 20mg/kg intra muscular and xylazine 2mg/kg intra muscular ). The ambulance was equipped with an examination table and equipment for...10. Lemke S, Cockerham GC, Glynn-Milley C, Cockerham KP (2013) Visual quality of life in veterans with blast-induced traumatic brain injury. JAMA

  12. Reduction of sidewall inclination and blast lag of powder blasted channels

    NARCIS (Netherlands)

    Wensink, H.; Elwenspoek, Michael Curt

    2002-01-01

    Powder blasting (abrasive jet machining) is a fast directional machining technique for brittle materials like silicon and glass. The cross-section of a powder blasted channel has a rounded V-shape. These inclined sidewalls are caused by the typical impact angle dependent removal rate for brittle

  13. Blast-Induced Acceleration in a Shock Tube: Distinguishing Primary and Tertiary Blast Injury

    Science.gov (United States)

    2015-10-01

    neurobiological mechanisms of injury as a rational basis for defining risks and establishing effective countermeasures. The etiology of blast TBI (bTBI...single .034” thick Valmex membrane produces a blast static pressure of 20 psi. To achieve that pressure with the previously-used acetate/ fiberglass

  14. Numerical simulation of the fluid-structure interaction between air blast waves and soil structure

    Science.gov (United States)

    Umar, S.; Risby, M. S.; Albert, A. Luthfi; Norazman, M.; Ariffin, I.; Alias, Y. Muhamad

    2014-03-01

    Normally, an explosion threat on free field especially from high explosives is very dangerous due to the ground shocks generated that have high impulsive load. Nowadays, explosion threats do not only occur in the battlefield, but also in industries and urban areas. In industries such as oil and gas, explosion threats may occur on logistic transportation, maintenance, production, and distribution pipeline that are located underground to supply crude oil. Therefore, the appropriate blast resistances are a priority requirement that can be obtained through an assessment on the structural response, material strength and impact pattern of material due to ground shock. A highly impulsive load from ground shocks is a dynamic load due to its loading time which is faster than ground response time. Of late, almost all blast studies consider and analyze the ground shock in the fluid-structure interaction (FSI) because of its influence on the propagation and interaction of ground shock. Furthermore, analysis in the FSI integrates action of ground shock and reaction of ground on calculations of velocity, pressure and force. Therefore, this integration of the FSI has the capability to deliver the ground shock analysis on simulation to be closer to experimental investigation results. In this study, the FSI was implemented on AUTODYN computer code by using Euler-Godunov and the arbitrary Lagrangian-Eulerian (ALE). Euler-Godunov has the capability to deliver a structural computation on a 3D analysis, while ALE delivers an arbitrary calculation that is appropriate for a FSI analysis. In addition, ALE scheme delivers fine approach on little deformation analysis with an arbitrary motion, while the Euler-Godunov scheme delivers fine approach on a large deformation analysis. An integrated scheme based on Euler-Godunov and the arbitrary Lagrangian-Eulerian allows us to analyze the blast propagation waves and structural interaction simultaneously.

  15. Neuro-Glial and Systemic Mechanisms of Pathological Responses in Rat Models of Primary Blast Overpressure Compared to “Composite” Blast

    OpenAIRE

    Svetlov, Stanislav I; Victor ePrima; Olena eGlushakova; Artem eSvetlov; Daniel eKirk; Hector eGutierrez; Victor eSerebruany; Kenneth eCurley; Wang, Kevin K. W.; Hayes, Ronald L.

    2012-01-01

    A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position toward blast generated by an external shock tube. In this study, we further characterized blast producing moderate traumatic brain injury and defined “composite” blast and ...

  16. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  17. A Table-top Blast Driven Shock Tube

    OpenAIRE

    Courtney, Michael; Courtney, Amy

    2011-01-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The d...

  18. Extreme Programming: Maestro Style

    Science.gov (United States)

    Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang; Powell, Mark

    2009-01-01

    "Extreme Programming: Maestro Style" is the name of a computer programming methodology that has evolved as a custom version of a methodology, called extreme programming that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA's Jet Propulsion Laboratory that develops software for Mars exploration missions. Extreme programming is oriented toward agile development of software resting on values of simplicity, communication, testing, and aggressiveness. Extreme programming involves use of methods of rapidly building and disseminating institutional knowledge among members of a computer-programming team to give all the members a shared view that matches the view of the customers for whom the software system is to be developed. Extreme programming includes frequent planning by programmers in collaboration with customers, continually examining and rewriting code in striving for the simplest workable software designs, a system metaphor (basically, an abstraction of the system that provides easy-to-remember software-naming conventions and insight into the architecture of the system), programmers working in pairs, adherence to a set of coding standards, collaboration of customers and programmers, frequent verbal communication, frequent releases of software in small increments of development, repeated testing of the developmental software by both programmers and customers, and continuous interaction between the team and the customers. The environment in which the Maestro team works requires the team to quickly adapt to changing needs of its customers. In addition, the team cannot afford to accept unnecessary development risk. Extreme programming enables the Maestro team to remain agile and provide high-quality software and service to its customers. However, several factors in the Maestro environment have made it necessary to modify some of the conventional extreme

  19. Electronics for Extreme Environments

    Science.gov (United States)

    Patel, J. U.; Cressler, J.; Li, Y.; Niu, G.

    2001-01-01

    Most of the NASA missions involve extreme environments comprising radiation and low or high temperatures. Current practice of providing friendly ambient operating environment to electronics costs considerable power and mass (for shielding). Immediate missions such as the Europa orbiter and lander and Mars landers require the electronics to perform reliably in extreme conditions during the most critical part of the mission. Some other missions planned in the future also involve substantial surface activity in terms of measurements, sample collection, penetration through ice and crust and the analysis of samples. Thus it is extremely critical to develop electronics that could reliably operate under extreme space environments. Silicon On Insulator (SOI) technology is an extremely attractive candidate for NASA's future low power and high speed electronic systems because it offers increased transconductance, decreased sub-threshold slope, reduced short channel effects, elimination of kink effect, enhanced low field mobility, and immunity from radiation induced latch-up. A common belief that semiconductor devices function better at low temperatures is generally true for bulk devices but it does not hold true for deep sub-micron SOI CMOS devices with microscopic device features of 0.25 micrometers and smaller. Various temperature sensitive device parameters and device characteristics have recently been reported in the literature. Behavior of state of the art technology devices under such conditions needs to be evaluated in order to determine possible modifications in the device design for better performance and survivability under extreme environments. Here, we present a unique approach of developing electronics for extreme environments to benefit future NASA missions as described above. This will also benefit other long transit/life time missions such as the solar sail and planetary outposts in which electronics is out open in the unshielded space at the ambient space

  20. Fatigue behavior of Ti6Al4V and 316 LVM blasted with ceramic particles of interest for medical devices.

    Science.gov (United States)

    Barriuso, S; Chao, J; Jiménez, J A; García, S; González-Carrasco, J L

    2014-02-01

    Grit blasting is used as a cost-effective method to increase the surface roughness of metallic biomaterials, as Ti6Al4V and 316 LVM, to enhance the osteointegration, fixation and stability of implants. Samples of these two alloys were blasted by using alumina and zirconia particles, yielding rough (up to Ra~8μm) and nearly smooth (up to Ra~1μm) surfaces, respectively. In this work, we investigate the sub-surface induced microstructural effects and its correlation with the mechanical properties, with special emphasis in the fatigue behavior. Blasting with zirconia particles increases the fatigue resistance whereas the opposite effect is observed using alumina ones. As in a conventional shot penning process, the use of rounded zirconia particles for blasting led to the development of residual compressive stresses at the surface layer, without zones of stress concentrators. Alumina particles are harder and have an angular shape, which confers a higher capability to abrade the surface, but also a high rate of breaking down on impact. The higher roughness and the presence of a high amount of embedded alumina particles make the blasted alloy prone to crack nucleation. Interestingly, the beneficial or detrimental role of blasting is more intense for the Ti6Al4V alloy than for the 316 steel. It is proposed that this behavior is related to their different strain hardening exponents and the higher mass fraction of particles contaminating the surface. The low value of this exponent for the Ti6Al4V alloy justifies the expected low sub-surface hardening during the severe plastic deformation, enhancing its capability to soft during cyclic loading. © 2013 Published by Elsevier Ltd.

  1. Information modeling system for blast furnace control

    Science.gov (United States)

    Spirin, N. A.; Gileva, L. Y.; Lavrov, V. V.

    2016-09-01

    Modern Iron & Steel Works as a rule are equipped with powerful distributed control systems (DCS) and databases. Implementation of DSC system solves the problem of storage, control, protection, entry, editing and retrieving of information as well as generation of required reporting data. The most advanced and promising approach is to use decision support information technologies based on a complex of mathematical models. The model decision support system for control of blast furnace smelting is designed and operated. The basis of the model system is a complex of mathematical models created using the principle of natural mathematical modeling. This principle provides for construction of mathematical models of two levels. The first level model is a basic state model which makes it possible to assess the vector of system parameters using field data and blast furnace operation results. It is also used to calculate the adjustment (adaptation) coefficients of the predictive block of the system. The second-level model is a predictive model designed to assess the design parameters of the blast furnace process when there are changes in melting conditions relative to its current state. Tasks for which software is developed are described. Characteristics of the main subsystems of the blast furnace process as an object of modeling and control - thermal state of the furnace, blast, gas dynamic and slag conditions of blast furnace smelting - are presented.

  2. Evaluating Primary Blast Effects In Vitro.

    Science.gov (United States)

    Logan, Niall J; Arora, Hari; Higgins, Claire A

    2017-09-18

    Exposure to blast events can cause severe trauma to vital organs such as the lungs, ears, and brain. Understanding the mechanisms behind such blast-induced injuries is of great importance considering the recent trend towards the use of explosives in modern warfare and terrorist-related incidents. To fully understand blast-induced injury, we must first be able to replicate such blast events in a controlled environment using a reproducible method. In this technique using shock tube equipment, shock waves at a range of pressures can be propagated over live cells grown in 2D, and markers of cell viability can be immediately analyzed using a redox indicator assay and the fluorescent imaging of live and dead cells. This method demonstrated that increasing the peak blast overpressure to 127 kPa can stimulate a significant drop in cell viability when compared to untreated controls. Test samples are not limited to adherent cells, but can include cell suspensions, whole-body and tissue samples, through minor modifications to the shock tube setup. Replicating the exact conditions that tissues and cells experience when exposed to a genuine blast event is difficult. Techniques such as the one presented in this article can help to define damage thresholds and identify the transcriptional and epigenetic changes within cells that arise from shock wave exposure.

  3. Controlled Low-Pressure Blast-Wave Exposure Causes Distinct Behavioral and Morphological Responses Modelling Mild Traumatic Brain Injury, Post-Traumatic Stress Disorder, and Comorbid Mild Traumatic Brain Injury-Post-Traumatic Stress Disorder.

    Science.gov (United States)

    Zuckerman, Amitai; Ram, Omri; Ifergane, Gal; Matar, Michael A; Sagi, Ram; Ostfeld, Ishay; Hoffman, Jay R; Kaplan, Zeev; Sadot, Oren; Cohen, Hagit

    2017-01-01

    The intense focus in the clinical literature on the mental and neurocognitive sequelae of explosive blast-wave exposure, especially when comorbid with post-traumatic stress-related disorders (PTSD) is justified, and warrants the design of translationally valid animal studies to provide valid complementary basic data. We employed a controlled experimental blast-wave paradigm in which unanesthetized animals were exposed to visual, auditory, olfactory, and tactile effects of an explosive blast-wave produced by exploding a thin copper wire. By combining cognitive-behavioral paradigms and ex vivo brain MRI to assess mild traumatic brain injury (mTBI) phenotype with a validated behavioral model for PTSD, complemented by morphological assessments, this study sought to examine our ability to evaluate the biobehavioral effects of low-intensity blast overpressure on rats, in a translationally valid manner. There were no significant differences between blast- and sham-exposed rats on motor coordination and strength, or sensory function. Whereas most male rats exposed to the blast-wave displayed normal behavioral and cognitive responses, 23.6% of the rats displayed a significant retardation of spatial learning acquisition, fulfilling criteria for mTBI-like responses. In addition, 5.4% of the blast-exposed animals displayed an extreme response in the behavioral tasks used to define PTSD-like criteria, whereas 10.9% of the rats developed both long-lasting and progressively worsening behavioral and cognitive "symptoms," suggesting comorbid PTSD-mTBI-like behavioral and cognitive response patterns. Neither group displayed changes on MRI. Exposure to experimental blast-wave elicited distinct behavioral and morphological responses modelling mTBI-like, PTSD-like, and comorbid mTBI-PTSD-like responses. This experimental animal model can be a useful tool for elucidating neurobiological mechanisms underlying the effects of blast-wave-induced mTBI and PTSD and comorbid mTBI-PTSD.

  4. SparkBLAST: scalable BLAST processing using in-memory operations.

    Science.gov (United States)

    de Castro, Marcelo Rodrigo; Tostes, Catherine Dos Santos; Dávila, Alberto M R; Senger, Hermes; da Silva, Fabricio A B

    2017-06-27

    The demand for processing ever increasing amounts of genomic data has raised new challenges for the implementation of highly scalable and efficient computational systems. In this paper we propose SparkBLAST, a parallelization of a sequence alignment application (BLAST) that employs cloud computing for the provisioning of computational resources and Apache Spark as the coordination framework. As a proof of concept, some radionuclide-resistant bacterial genomes were selected for similarity analysis. Experiments in Google and Microsoft Azure clouds demonstrated that SparkBLAST outperforms an equivalent system implemented on Hadoop in terms of speedup and execution times. The superior performance of SparkBLAST is mainly due to the in-memory operations available through the Spark framework, consequently reducing the number of local I/O operations required for distributed BLAST processing.

  5. 30 CFR 75.1320 - Multiple-shot blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Multiple-shot blasting. 75.1320 Section 75.1320... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1320 Multiple-shot blasting... first shot or shots fired in a round shall be initiated in the row nearest the kerf or the row or rows...

  6. Blast Resistance of Slurry Infiltrated Fibre Concrete with Waste Steel Fibres from Tires

    Directory of Open Access Journals (Sweden)

    Drdlová Martina

    2018-01-01

    Full Text Available The utilization of waste steel fibres (coming from the recycling process of the old tires in production of blast resistant cement based panels was assessed. Waste fibres were incorporated in slurry infiltrated fibre concrete (SIFCON, which is a special type of ultra-highperformance fibre reinforced concrete with high fibre content. The technological feasibility (i.e. suitability of the waste fibres for SIFCON technology was assessed using homogeneity test. Test specimens were prepared with three volume fractions (5; 7.5 and 10 % by vol. of waste unclassified fibres. SIFCON with industrial steel fibres (10% by vol. and ultra-highperformance fibre concrete with industrial fibres were also cast and tested for comparison purposes. Quasi-static mechanical properties were determined. Real blast tests were performed on the slab specimens (500x500x40 mm according to the modified methodology M-T0-VTU0 10/09. Damage of the slab, the change of the ultrasound wave velocity propagation in the slab specimen before and after the blast load in certain measurement points, the weight of fragments and their damage potential were evaluated and compared. Realized tests confirmed the possibility of using the waste fibres for SIFCON technology. The obtained results indicate, that the usage of waste fibres does not significantly reduce the values of SIFCON flexural and compressive strength at quasi-static load - the values were comparable to the specimens with industrially produced fibres. With increasing fibre content, the mechanical parameters are increasing as well. Using of the waste fibres reduces fragmentation of SIFCON at blast load due to the fibre size parameters. Using of low diameter fibres means more fibres in the matrix and thus better homogeneity of the whole composite with less unreinforced areas. Regarding the blast tests, the specimen with waste steel fibres showed the best resistance and outperformed also the specimen with commercial fibres. Using of

  7. Extremely deformable structures

    CERN Document Server

    2015-01-01

    Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

  8. Statistics of Extremes

    KAUST Repository

    Davison, Anthony C.

    2015-04-10

    Statistics of extremes concerns inference for rare events. Often the events have never yet been observed, and their probabilities must therefore be estimated by extrapolation of tail models fitted to available data. Because data concerning the event of interest may be very limited, efficient methods of inference play an important role. This article reviews this domain, emphasizing current research topics. We first sketch the classical theory of extremes for maxima and threshold exceedances of stationary series. We then review multivariate theory, distinguishing asymptotic independence and dependence models, followed by a description of models for spatial and spatiotemporal extreme events. Finally, we discuss inference and describe two applications. Animations illustrate some of the main ideas. © 2015 by Annual Reviews. All rights reserved.

  9. Antibacterial Efficacy of a New Gentamicin-Coating for Cementless Prostheses Compared to Gentamicin-Loaded Bone Cement

    NARCIS (Netherlands)

    Neut, Danielle; Dijkstra, Rene J. B.; Thompson, Jonathan I.; van der Mei, Henny C.; Busscher, Henk J.

    2011-01-01

    Cementless prostheses are increasingly popular but require alternative prophylactic measures than the use of antibiotic-loaded bone cements. Here, we determine the 24-h growth inhibition of gentamicin-releasing coatings from grit-blasted and porous-coated titanium alloys, and compare their

  10. Adventure and Extreme Sports.

    Science.gov (United States)

    Gomez, Andrew Thomas; Rao, Ashwin

    2016-03-01

    Adventure and extreme sports often involve unpredictable and inhospitable environments, high velocities, and stunts. These activities vary widely and include sports like BASE jumping, snowboarding, kayaking, and surfing. Increasing interest and participation in adventure and extreme sports warrants understanding by clinicians to facilitate prevention, identification, and treatment of injuries unique to each sport. This article covers alpine skiing and snowboarding, skateboarding, surfing, bungee jumping, BASE jumping, and whitewater sports with emphasis on epidemiology, demographics, general injury mechanisms, specific injuries, chronic injuries, fatality data, and prevention. Overall, most injuries are related to overuse, trauma, and environmental or microbial exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Extremal graph theory

    CERN Document Server

    Bollobas, Bela

    2004-01-01

    The ever-expanding field of extremal graph theory encompasses a diverse array of problem-solving methods, including applications to economics, computer science, and optimization theory. This volume, based on a series of lectures delivered to graduate students at the University of Cambridge, presents a concise yet comprehensive treatment of extremal graph theory.Unlike most graph theory treatises, this text features complete proofs for almost all of its results. Further insights into theory are provided by the numerous exercises of varying degrees of difficulty that accompany each chapter. A

  12. Modelling and Simulation of Wave Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    A simple model of the wave load on slender members of offshore structures is described. The wave elevation of the sea state is modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...... velocity can be approximated by a Gaussian Markov process. Known approximate results for the first-passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results...

  13. Spinal Epidural Hematoma Due To Tyre-Blast Injury: A Case Report.

    Science.gov (United States)

    Boyaci, Mehmet G; Aslan, Adem; Tünay, Kamil; Karademir, Mustafa; Aydoğmuş, Arda

    2017-01-15

    A retrospective case report. The objective of this article is to report a spinal epidural hematoma (SEH) due to shock wave. SEH is an infrequent condition. Most of SEH's are spontaneous. We have reported an SEH traumatic case without bone lesions due to exploding truck tire. A different category of blast injuries is the one related with exploding tyres. Shock waves are the main mechanism that is responsible for blast injuries. We are presenting the first report of acute SEH due to shock wave. A 33-year-old man was brought to the emergency department with complaints of weakness and numbness of the upper extremities. There was an epidural high-signal density without osseous lesion in computerized tomography from the level of C2 to C5, and there was a T2-weighted hyperintense lesion in magnetic resonance imaging from the level of C2 to C5 with compression of the spinal cord the anterior and posterior which proved to be an SEH. The patient was discharged from the hospital with complete neurologic recovery. SEH should be considered possible in the blast injury. SEH condition carries a significant risk of morbidity and mortality without early recognition and rapid management. 5.

  14. The blast wave mitigation effects of a magnetogasdynamic decelerator

    Energy Technology Data Exchange (ETDEWEB)

    Baty, Roy S [Los Alamos National Laboratory; Lundgren, Ronald G [APPLIED RESEARCH ASSOCIATES; Tucker, Don H [UNIV OF UTAH

    2009-01-01

    This work computes shock wave jump functions for viscous blast waves propagating in a magnetogasdynamic decelerator. The decelerator is assumed to be a one-dimensional channel with sides that are perfect conductors. An electric field applied on the walls of the channel produces a magnetogasdynamic pump, which decelerates the flow field induced by a blast wave. The blast wave jump functions computed here are compared to magnetogasdynamic results for steady supersonic channel flow to quantify potential blast mitigation effects. Theoretical shock wave jump functions are also presented for inviscid blast waves propagating in a one-dimensional channel with an electromagnetic field.

  15. Acute lower extremity ischaemia

    African Journals Online (AJOL)

    In a nutshell. • A patient with sudden onset of a cold, weak, numb and painful foot has acute lower extremity ischaemia (ALEXI) until proven otherwise. Labelling patients as acute gout, acute phlegmasia (deep vein thrombosis), acute sciatica, etc. may result in unnecessary delays in treatment, with tragic consequences.

  16. Injuries in extreme sports.

    Science.gov (United States)

    Laver, Lior; Pengas, Ioannis P; Mei-Dan, Omer

    2017-04-18

    Extreme sports (ES) are usually pursued in remote locations with little or no access to medical care with the athlete competing against oneself or the forces of nature. They involve high speed, height, real or perceived danger, a high level of physical exertion, spectacular stunts, and heightened risk element or death.Popularity for such sports has increased exponentially over the past two decades with dedicated TV channels, Internet sites, high-rating competitions, and high-profile sponsors drawing more participants.Recent data suggest that the risk and severity of injury in some ES is unexpectedly high. Medical personnel treating the ES athlete need to be aware there are numerous differences which must be appreciated between the common traditional sports and this newly developing area. These relate to the temperament of the athletes themselves, the particular epidemiology of injury, the initial management following injury, treatment decisions, and rehabilitation.The management of the injured extreme sports athlete is a challenge to surgeons and sports physicians. Appropriate safety gear is essential for protection from severe or fatal injuries as the margins for error in these sports are small.The purpose of this review is to provide an epidemiologic overview of common injuries affecting the extreme athletes through a focus on a few of the most popular and exciting extreme sports.

  17. Deficiently extremal Gorenstein algebras

    Indian Academy of Sciences (India)

    For the given codimension g ≥ 3 and initial degree p ≥ 2, a Gorenstein algebra R/I with minimal multiplicity is extremal in the sense of Schenzel [8]. This has a nice structural implication: the minimal resolution of R/I must be pure and almost linear, and so their. Betti numbers are given by Herzog and Kühl [3] formulae.

  18. Hydrological extremes and security

    Directory of Open Access Journals (Sweden)

    Z. W. Kundzewicz

    2015-04-01

    Full Text Available Economic losses caused by hydrological extremes – floods and droughts – have been on the rise. Hydrological extremes jeopardize human security and impact on societal livelihood and welfare. Security can be generally understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. The traditional interpretation of security, focused on the state military capabilities, has been replaced by a wider understanding, including economic, societal and environmental aspects that get increasing attention. Floods and droughts pose a burden and serious challenges to the state that is responsible for sustaining economic development, and societal and environmental security. The latter can be regarded as the maintenance of ecosystem services, on which a society depends. An important part of it is water security, which can be defined as the availability of an adequate quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, environments and economies. Security concerns arise because, over large areas, hydrological extremes − floods and droughts − are becoming more frequent and more severe. In terms of dealing with water-related risks, climate change can increase uncertainties, which makes the state’s task to deliver security more difficult and more expensive. However, changes in population size and development, and level of protection, drive exposure to hydrological hazards.

  19. Extremism and Disability Chic

    Science.gov (United States)

    Kauffman, James M.; Badar, Jeanmarie

    2018-01-01

    The word chic refers to something fashionable or stylish. Chic varies for individuals and groups and with time and place. Something chic may have desirable or undesirable long-term consequences. Disability and extremism are also changeable concepts, depending on comparison to social norms. People with disabilities should have the option of being…

  20. Modelling rock fragmentation of Extremely Energetic Rockfalls

    Science.gov (United States)

    De Blasio, Fabio; Dattola, Giuseppe; Battista Crosta, Giovanni

    2017-04-01

    Extremely energetic rockfalls (EER) are phenomena for which the combination of a large volume (at least some thousands of m ) and a free fall height of hundreds of metres, results in a large released energy. We fix a threshold value of around 1/50 of kilotons to define such a type of events. Documented examples include several events with dif-ferent size in the Alps (Dru, 2005, 2011, 265,000, 59,200 m3; val Fiscalina - Cima Una, 2007, 40,000 m3; Thurwieser 2004, ca 2 Mm3; Cengalo, 2011, 1.5*105 m3 in 2016, in Switzerland; Civetta, 2013, ca 50,000 m3;), in the Apennines (Gran Sasso, 2006, 30,000 m3), Rocky Mountains (Yosemite, Happy Isles, 38,000 m3), and Himalaya. EERs may become more frequent on steep and sharp mountain peaks as a consequence of permafrost thawing at higher altitudes. In contrast to low energy rockfalls where block disintegration is limited, in EERs the impact after free fall causes an immediate and efficient release of energy much like an explosion. The severe disintegration of the rock and the corresponding air blast are capable of snapping trees many hundreds of metres ahead of the fall area. Pulverized rock at high speed can abrade tree logs, and the resulting suspension flow may travel much further the impact zone, blanketing vast surrounding areas. Using both published accounts of some of these events and collecting direct data for some of them, we present some basic models to describe the involved processes based on analogies with explosions and explosive fragmentation. Of the initial energy, one part is used up in the rock disintegration, and the rest is shared between the shock wave and air blast. The fragmentation energy is calculated based on the fitting of the dust size spectrum by using different proba-bilistic distribution laws and the definition of a surface energy and by considering the involved strain rate. We find the fragmentation is around one third of the initial boulder energy. Finally, we evaluate the velocity of the

  1. Geomechanical effects of stress shadow created by large-scale destress blasting

    Directory of Open Access Journals (Sweden)

    Isaac Vennes

    2017-12-01

    Full Text Available This study aims to determine if large-scale choked panel destress blasting can provide sufficient beneficial stress reduction in highly-stressed remnant ore pillar that is planned for production. The orebody is divided into 20 stopes over 2 levels, and 2 panels are choke-blasted in the hanging wall to shield the ore pillar by creating a stress shadow around it. A linear-elastic model of the mining system is constructed with finite difference code FLAC3D. The effect of destress blasting in the panels is simulated by applying a fragmentation factor (α to the rock mass stiffness and a stress reduction factor (β to the current state of stress in the region occupied by the destress panels. As an extreme case, the destress panel is also modeled as a void to obtain the maximum possible beneficial effects of destressing and stress shadow. Four stopes are mined in the stress shadow of the panels in 6 lifts and then backfilled. The effect of destress blasting on the remnant ore pillar is quantified based on stress change and brittle shear ratio (BSR in the stress shadow zone compared to the base case without destress blasting. To establish realistic rock fragmentation and stress reduction factors, model results are compared to measured stress changes reported for case studies at Fraser and Brunswick mines. A 1.5 MPa immediate stress decrease was observed 20 m away from the panel at Fraser Mine, and a 4 MPa immediate stress decrease was observed 25 m away at Brunswick Mine. Comparable results are obtained from the current model with a rock fragmentation factor α of 0.2 and a stress reduction factor β of 0.8. It is shown that a destress blasting with these parameters reduces the major principal stress in the nearest stopes by 10–25 MPa. This yields an immediate reduction of BSR, which is deemed sufficient to reduce volume of ore at risk in the pillar.

  2. Electrical load detection aparatus

    DEFF Research Database (Denmark)

    2010-01-01

    A load detection technique for a load comprising multiple frequency-dependant sub-loads comprises measuring a representation of the impedance characteristic of the load; providing stored representations of a multiplicity of impedance characteristics of the load; each one of the stored representat...

  3. LTC American`s, Inc. vacuum blasting machine: Baseline report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-31

    The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing focused on two main areas of exposure: dust and noise.

  4. Divide and Conquer (DC BLAST: fast and easy BLAST execution within HPC environments

    Directory of Open Access Journals (Sweden)

    Won Cheol Yim

    2017-06-01

    Full Text Available Bioinformatics is currently faced with very large-scale data sets that lead to computational jobs, especially sequence similarity searches, that can take absurdly long times to run. For example, the National Center for Biotechnology Information (NCBI Basic Local Alignment Search Tool (BLAST and BLAST+ suite, which is by far the most widely used tool for rapid similarity searching among nucleic acid or amino acid sequences, is highly central processing unit (CPU intensive. While the BLAST suite of programs perform searches very rapidly, they have the potential to be accelerated. In recent years, distributed computing environments have become more widely accessible and used due to the increasing availability of high-performance computing (HPC systems. Therefore, simple solutions for data parallelization are needed to expedite BLAST and other sequence analysis tools. However, existing software for parallel sequence similarity searches often requires extensive computational experience and skill on the part of the user. In order to accelerate BLAST and other sequence analysis tools, Divide and Conquer BLAST (DCBLAST was developed to perform NCBI BLAST searches within a cluster, grid, or HPC environment by using a query sequence distribution approach. Scaling from one (1 to 256 CPU cores resulted in significant improvements in processing speed. Thus, DCBLAST dramatically accelerates the execution of BLAST searches using a simple, accessible, robust, and parallel approach. DCBLAST works across multiple nodes automatically and it overcomes the speed limitation of single-node BLAST programs. DCBLAST can be used on any HPC system, can take advantage of hundreds of nodes, and has no output limitations. This freely available tool simplifies distributed computation pipelines to facilitate the rapid discovery of sequence similarities between very large data sets.

  5. 30 CFR 57.6404 - Separation of blasting circuits from power source.

    Science.gov (United States)

    2010-07-01

    ... NONMETAL MINES Explosives Electric Blasting-Surface and Underground § 57.6404 Separation of blasting... locked in the open position except when closed to fire the blast. (b) Lead wires shall not be connected...

  6. Impulsive Loading of Cellular Media in Sandwich Construction

    Science.gov (United States)

    Main, Joseph A.; Gazonas, George A.

    2006-07-01

    Motivated by recent efforts to mitigate blast loading using energy-absorbing materials, this paper investigates the uniaxial crushing of cellular media in sandwich construction under impulsive pressure loading. The cellular core is modeled using a rigid, perfectly-plastic, locking idealization, as in previous studies, and the front and back faces are modeled as rigid, with pressure loading applied to the front face and the back face unrestrained. Predictions of this analytical model show excellent agreement with explicit finite element computations, and the model is used to investigate the influence of the mass distribution between the core and the faces. Increasing the mass fraction in the front face is found to increase the impulse required for complete crushing of the cellular core but also to produce undesirable increases in back-face accelerations. Optimal mass distributions are investigated by maximizing the impulse capacity while limiting the back-face accelerations to a specified level.

  7. Nitrogen runoff from tunnel blasted rocks--a large-scale test.

    Science.gov (United States)

    Baekken, Torleif

    2014-06-01

    Eight tunnel blasted rock samples were washed five times in 10 m3 containers to calculate the runoff potential of nitrogen from unexploded remains of the ammonium nitrate slurry explosive in rock piles. During the first wash, 65% of total nitrogen was washed off. The average concentrations of NH4+ and NO3- in the first wash water were 46 mg N/L and 58 mg N/L, respectively, being reduced to 2.5 and 1.2 mg N/L after the last wash. The average runoff of total nitrogen from the blasted rocks was 24.2 g N/ton, being 14.7% of nitrogen in the loaded explosives. pH was high (range 8.1 to 11.8) resulting from shotcrete spill, pushing the NH4+/NH3 equilibrium toward the toxic NH3. The consequences of runoff from blasted rock piles may be damaging for water quality and biology in small recipients, and abatement measures should be assessed.

  8. A study in cost analysis of aggregate production as depending on drilling and blasting design

    Science.gov (United States)

    Bilim, Niyazi; Çelik, Arif; Kekeç, Bilgehan

    2017-10-01

    Since aggregate production has vital importance for many engineering projects-such as construction, highway and plant-mixed concrete production-this study was undertaken to determine how the costs for such production are affected by the design of drilling and blasting processes used. Aggregates are used in the production of concrete and asphalt, which are critical resources for the construction sector. The ongoing population increase and the growth of living standards around the world drive the increasing demand for these products. As demand grows, competition has naturally arisen among producers in the industry. Competition in the market has directly affected prices, which leads to the need for new measures and cost analysis on production costs. The cost calculation is one of the most important parameters in mining activities. Aggregate production operations include drilling, blasting, secondary crushing (if necessary), loading, hauling and crushing-screening, and each of these factors affects cost. In this study, drilling and blasting design parameters (such as hole diameter, hole depth, hole distance and burden) were investigated and evaluated for their effect on the total cost of quarrying these products, based on a particular quarry selected for this research. As the result of evaluation, the parameters actually driving costs have been identified, and their effects on the cost have been determined. In addition, some suggestions are presented regarding production design which may lead to avoiding increased production costs.

  9. The Hydrodynamics of Blast-Wave-Driven Instabilities

    Science.gov (United States)

    Miles, Aaron R.

    2010-05-01

    Supernova explosions are among the most dramatic in the universe. Type II supernovae follow core collapse of a massive star, while Type Ia supernovae are typically believed to be thermonuclear explosions of carbon-oxygen white dwarfs that have accreted enough material to initiate carbon burning. In both cases, the explosion dynamics are complicated by hydrodynamic instabilities that make spherical symmetry impossible. Non-planar interactions of shocks with steep density gradients result in vorticity deposition that drives Richtmyer-Meshkov (RM) instability growth. Deceleration of those same shock-accelerated interfaces drives the ubiquitous Rayleigh-Taylor (RT) instability. These processes yield highly nonlinear structures that are further modified by shear-driven Kelvin-Helmholtz (KH) instabilities, and provide elemental mixing on a wide range of scales. A broad spectrum of approaches can be applied to study the role of hydrodynamic mixing in SNe. These range from analytic treatments of the fundamental instability problems of classical RT and steady-shock RM, to complex (often multiphysics) computational and experimental systems, including numerical simulations of supernovae and laser-driven laboratory. Between these two extremes lies a third fundamental instability problem that is more relevant than either RT or RM in isolation and somewhat less complex than the full system. Namely, an idealized blast-wave-driven problem in which a localized source drives a divergent Taylor-Sedov blast wave that in turn drives a perturbed interface between heavier and lighter gamma-law fluids. Within this context, we use numerical simulations and simplified analytic models to consider the effect of the initial perturbation spectrum in determining the late-time asymptotic state of the mixing zone, the interaction of multiple unstable interfaces relevant to core-collapse supernovae, and the proximity of the forward shock to the developing instability. This work performed under the

  10. Modelling and prediction of pig iron variables in the blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Saxen, H.; Laaksonen, M.; Waller, M. [Aabo Akademi, Turku (Finland). Heat Engineering Lab.

    1996-12-31

    The blast furnace, where pig iron for steelmaking is produced, is an extremely complicated process, with heat and mass transfer and chemical reactions between several phases. Very few direct measurements on the internal state are available in the operation of the process. A main problem in on-line analysis and modelling is that the state of the furnace may undergo spontaneous changes, which alter the dynamic behaviour of the process. Moreover, large internal disturbances frequently occur, which affect the product quality. The work in this research project focuses on a central problem in the control of the blast furnace process, i.e., short-term prediction of pig iron variables. The problem is of considerable importance for fuel economy, product quality, and for an optimal decision making in integrated steel plants. The operation of the blast furnace aims at producing a product (hot metal) with variables maintained on a stable level (close to their setpoints) without waste of expensive fuel (metallurgical coke). The hot metal temperature and composition affect the downstream (steelmaking) processes, so fluctuations in the pig iron quality must be `corrected` in the steel plant. The goal is to develop a system which predicts the evolution of the hot metal variables (temperature, chemical composition) during the next few taps, and that can be used for decision-making in the operation of the blast furnace. Because of the complicated behaviour of the process, it is considered important to include both deterministic and stochastic components in the modelling: Mathematical models, which on the basis of measurements describe the physical state of the process, and statistical (black-box) models will be combined in the system. Moreover, different models will be applied in different domains in order to capture structural changes in the dynamics of the process SULA 2 Research Programme; 17 refs.

  11. Blast injuries of large tyres: case series.

    Science.gov (United States)

    Hefny, Ashraf F; Eid, Hani O; Al-Bashir, Mohamed; Abu-Zidan, Fikri M

    2010-01-01

    Severe blast injuries of large tyres are similar to those resulting from landmine explosions with neither thermal nor chemical effects. Little has been written about the destructive nature of these blasts. To evaluate our clinical management of patients involved in large tyre blasts. All patients who had tyre blast injuries and were admitted to Al-Ain or Tawam Hospitals between March 2003 and September 2009 were retrospectively studied. Clinical presentation, mechanism of injury, management, and outcome were reviewed. Seven male patients were studied. They had a median (range) age of 38 (20-53) years. Four patients (57%) were inflating the tyre when it suddenly exploded. On arrival to the hospital, two patients were unconscious with GCS of 3/15. Six patients (86%) had head/face trauma. Three patients had multiple injuries to different body parts (43%). The median (range) injury severity score was 14 (10-33). Four patients (57%) were operated on. Five patients were admitted to the ICU with a median (range) ICU stay of 2 (1-2) days. The median (range) total hospital stay was 3 (1-14) days. Two patients died (overall mortality 29%). The high energy produced by large tyre blasts may cause severe injuries leading to high morbidity and mortality. Preventive occupational methods should be adopted and implemented at the work place. Copyright 2009 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  12. Distribution load estimation (DLE)

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A.; Lehtonen, M. [VTT Energy, Espoo (Finland)

    1998-08-01

    The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented

  13. Non-extremal branes

    Directory of Open Access Journals (Sweden)

    Pablo Bueno

    2015-04-01

    Full Text Available We prove that for arbitrary black brane solutions of generic Supergravities there is an adapted system of variables in which the equations of motion are exactly invariant under electric–magnetic duality, i.e. the interchange of a given extended object by its electromagnetic dual. We obtain thus a procedure to automatically construct the electromagnetic dual of a given brane without needing to solve any further equation. We apply this procedure to construct the non-extremal (p,q-string of Type-IIB String Theory (new in the literature, explicitly showing how the dual (p,q-five-brane automatically arises in this construction. In addition, we prove that the system of variables used is suitable for a generic characterization of every double-extremal Supergravity brane solution, which we perform in full generality.

  14. Resistance of Multi-Wythe Insulted Masonry Walls Subjected to Impulse Loads. Volume 1

    Science.gov (United States)

    2008-12-01

    stiffness until it begins to lock up during extreme compressive strain. Another nonlinearity that foam possesses is viscoelastic behavior, which means...LS-DYNA includes several options of material cards for modeling foam . Some are tailored to certain types of foam such as polyurethane . Some of...potential application of foam insulation as a blast-resistant material. The project was closely coordinated with full-scale explosive testing

  15. Extremes in nature

    CERN Document Server

    Salvadori, Gianfausto; Kottegoda, Nathabandu T

    2007-01-01

    This book is about the theoretical and practical aspects of the statistics of Extreme Events in Nature. Most importantly, this is the first text in which Copulas are introduced and used in Geophysics. Several topics are fully original, and show how standard models and calculations can be improved by exploiting the opportunities offered by Copulas. In addition, new quantities useful for design and risk assessment are introduced.

  16. Investigation of cavitation as a possible damage mechanism in blast-induced traumatic brain injury.

    Science.gov (United States)

    Goeller, Jacques; Wardlaw, Andrew; Treichler, Derrick; O'Bruba, Joseph; Weiss, Greg

    2012-07-01

    Cavitation was investigated as a possible damage mechanism for war-related traumatic brain injury (TBI) due to an improvised explosive device (IED) blast. When a frontal blast wave encounters the head, a shock wave is transmitted through the skull, cerebrospinal fluid (CSF), and tissue, causing negative pressure at the contrecoup that may result in cavitation. Numerical simulations and shock tube experiments were conducted to determine the possibility of cranial cavitation from realistic IED non-impact blast loading. Simplified surrogate models of the head consisted of a transparent polycarbonate ellipsoid. The first series of tests in the 18-inch-diameter shock tube were conducted on an ellipsoid filled with degassed water to simulate CSF and tissue. In the second series, Sylgard gel, surrounded by a layer of degassed water, was used to represent the tissue and CSF, respectively. Simulated blast overpressure in the shock tube tests ranged from a nominal 10-25 pounds per square inch gauge (psig; 69-170 kPa). Pressure in the simulated CSF was determined by Kulite thin line pressure sensors at the coup, center, and contrecoup positions. Using video taken at 10,000 frames/sec, we verified the presence of cavitation bubbles at the contrecoup in both ellipsoid models. In all tests, cavitation at the contrecoup was observed to coincide temporally with periods of negative pressure. Collapse of the cavitation bubbles caused by the surrounding pressure and elastic rebound of the skull resulted in significant pressure spikes in the simulated CSF. Numerical simulations using the DYSMAS hydrocode to predict onset of cavitation and pressure spikes during cavity collapse were in good agreement with the tests. The numerical simulations and experiments indicate that skull deformation is a significant factor causing cavitation. These results suggest that cavitation may be a damage mechanism contributing to TBI that requires future study.

  17. Distribution load estimation - DLE

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland)

    1996-12-31

    The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

  18. Paint removal using wheat starch blast media

    Science.gov (United States)

    Foster, Terry; Oestreich, John

    1993-03-01

    A review of the Wheat Starch Blasting technology is presented. Laboratory evaluations covering Almen Arc testing on bare 2024-T3 aluminum and magnesium, as well as crack detection on 7075-T6 bare aluminum, are discussed. Comparisons with Type V plastic media show lower residual stresses are achieved on aluminum and magnesium with wheat starch media. Dry blasting effects on the detection of cracks confirms better crack visibility with wheat starch media versus Type V or Type II plastic media. Testing of wheat starch media in several composite test programs, including fiberglass, Kevlar, and graphite-epoxy composites, showed no fiber damage. Process developments and production experience at the first U.S. aircraft stripping facility are also reviewed. Corporate and regional aircraft are being stripped in this three nozzle dry blast hanger.

  19. Moving in extreme environments

    DEFF Research Database (Denmark)

    Lucas, Samuel J E; Helge, Jørn W; Schütz, Uwe H W

    2016-01-01

    they are set; present the pros and cons for self versus prescribed acute and chronic exposure; describe humans' (mal)adaptations; and finally suggest future directions for practice and research. In summary, we describe adaptation patterns that are often U or J shaped and that over time minimal or no load...... be studied in this perspective. With improved access to insightful and portable technologies, there are some exciting possibilities to explore these questions in this context....

  20. Standardized Loads Acting in Knee Implants

    Science.gov (United States)

    Bergmann, Georg; Bender, Alwina; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Trepczynski, Adam; Heller, Markus O.; Kutzner, Ines

    2014-01-01

    The loads acting in knee joints must be known for improving joint replacement, surgical procedures, physiotherapy, biomechanical computer simulations, and to advise patients with osteoarthritis or fractures about what activities to avoid. Such data would also allow verification of test standards for knee implants. This work analyzes data from 8 subjects with instrumented knee implants, which allowed measuring the contact forces and moments acting in the joint. The implants were powered inductively and the loads transmitted at radio frequency. The time courses of forces and moments during walking, stair climbing, and 6 more activities were averaged for subjects with I) average body weight and average load levels and II) high body weight and high load levels. During all investigated activities except jogging, the high force levels reached 3,372–4,218N. During slow jogging, they were up to 5,165N. The peak torque around the implant stem during walking was 10.5 Nm, which was higher than during all other activities including jogging. The transverse forces and the moments varied greatly between the subjects, especially during non-cyclic activities. The high load levels measured were mostly above those defined in the wear test ISO 14243. The loads defined in the ISO test standard should be adapted to the levels reported here. The new data will allow realistic investigations and improvements of joint replacement, surgical procedures for tendon repair, treatment of fractures, and others. Computer models of the load conditions in the lower extremities will become more realistic if the new data is used as a gold standard. However, due to the extreme individual variations of some load components, even the reported average load profiles can most likely not explain every failure of an implant or a surgical procedure. PMID:24465856

  1. Standardized loads acting in knee implants.

    Directory of Open Access Journals (Sweden)

    Georg Bergmann

    Full Text Available The loads acting in knee joints must be known for improving joint replacement, surgical procedures, physiotherapy, biomechanical computer simulations, and to advise patients with osteoarthritis or fractures about what activities to avoid. Such data would also allow verification of test standards for knee implants. This work analyzes data from 8 subjects with instrumented knee implants, which allowed measuring the contact forces and moments acting in the joint. The implants were powered inductively and the loads transmitted at radio frequency. The time courses of forces and moments during walking, stair climbing, and 6 more activities were averaged for subjects with I average body weight and average load levels and II high body weight and high load levels. During all investigated activities except jogging, the high force levels reached 3,372-4,218N. During slow jogging, they were up to 5,165N. The peak torque around the implant stem during walking was 10.5 Nm, which was higher than during all other activities including jogging. The transverse forces and the moments varied greatly between the subjects, especially during non-cyclic activities. The high load levels measured were mostly above those defined in the wear test ISO 14243. The loads defined in the ISO test standard should be adapted to the levels reported here. The new data will allow realistic investigations and improvements of joint replacement, surgical procedures for tendon repair, treatment of fractures, and others. Computer models of the load conditions in the lower extremities will become more realistic if the new data is used as a gold standard. However, due to the extreme individual variations of some load components, even the reported average load profiles can most likely not explain every failure of an implant or a surgical procedure.

  2. Mathematical model and software for control of commissioning blast furnace

    Science.gov (United States)

    Spirin, N. A.; Onorin, O. P.; Shchipanov, K. A.; Lavrov, V. V.

    2016-09-01

    Blowing-in is a starting period of blast furnace operation after construction or major repair. The current approximation methods of blowing-in burden analysis are based on blowing-in practice of previously commissioned blast furnaces. This area is theoretically underexplored; there are no common scientifically based methods for selection of the burden composition and blast parameters. The purpose of this paper is development and scientific substantiation of the methods for selection of the burden composition and blast parameters in the blast furnace during the blowing-in period. Research methods are based on physical regularities of main processes running in the blast furnace, system analysis, and application of modern principles for development and construction of mathematical models, algorithms and software designed for automated control of complex production processes in metallurgy. As consequence of the research made by the authors the following results have been achieved: 1. A set of mathematical models for analysis of burden arrangement throughout the height of the blast furnace and for selection of optimal blast and gas dynamic parameters has been developed. 2. General principles for selection of the blowing-in burden composition and blast and gas dynamic parameters have been set up. 3. The software for the engineering and process staff of the blast furnace has been developed and introduced in the industry.

  3. Acute Blast Injury Reduces Brain Abeta in Two Rodent Species

    Directory of Open Access Journals (Sweden)

    Rita eDe Gasperi

    2012-12-01

    Full Text Available Blast-induced traumatic brain injury (TBI has been a major cause of morbidity and mortality in the conflicts in Iraq and Afghanistan. How the primary blast wave affects the brain is not well understood. In particular, it is unclear whether blast injures the brain through mechanisms similar to those found in non-blast closed impact injuries (nbTBI. The β-amyloid (Aβ peptide associated with the development of Alzheimer’s disease (AD is elevated acutely following TBI in humans as well as in experimental animal models of nbTBI. We examined levels of brain Aβ following experimental blast injury using enzyme-linked immunosorbent assays for Aβ 40 and 42. In both rat and mouse models of blast injury, rather than being increased, endogenous rodent brain Aβ levels were decreased acutely following injury. Levels of the amyloid precursor protein (APP were increased following blast exposure although there was no evidence of axonal pathology based on APP immunohistochemical staining. Unlike the findings in nbTBI animal models, levels of the β-secretase, BACE-1, and the γ-secretase component presenilin-1 were unchanged following blast exposure. These studies have implications for understanding the nature of blast injury to the brain. They also suggest that strategies aimed at lowering Aβ production may not be effective for treating acute blast injury to the brain.

  4. Extracellular cyclophilin A protects against blast-induced neuronal injury.

    Science.gov (United States)

    Arun, Peethambaran; Abu-Taleb, Rania; Valiyaveettil, Manojkumar; Wang, Ying; Long, Joseph B; Nambiar, Madhusoodana P

    2013-01-01

    Blast-induced traumatic brain injury (TBI) and subsequent neurobehavioral deficits are major disabilities suffered by the military and civilian population worldwide. Rigorous scientific research is underway to understand the mechanism of blast TBI and thereby develop effective therapies for protection and treatment. By using an in vitro shock tube model of blast TBI with SH-SY5Y human neuroblastoma cells, we have demonstrated that blast exposure leads to neurobiological changes in an overpressure and time dependent manner. Paradoxically, repeated blast exposures resulted in less neuronal injury compared to single blast exposure and suggested a potential neuroprotective mechanism involving released cyclophilin A (CPA). In the present study, we demonstrate accumulation of CPA in the culture medium after repeated blast exposures supporting the notion of extracellular CPA mediated neuroprotection. Post-exposure treatment of the cells with purified recombinant CPA caused significant protection against blast-induced neuronal injury. Furthermore, repeated blast exposure was associated with phosphorylation of the proteins ERK1/2 and Bad suggesting a potential mechanism of neuroprotection by extracellular CPA and may aid in the development of targeted therapies for protection against blast-induced TBI. Copyright © 2013 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  5. Directional Considerations for Extreme Wind Climatic Events in the ...

    African Journals Online (AJOL)

    Because the extreme wind speed and direction are impossible to predict exactly, and any prediction is subject to uncertainties, the reliability of the line may be assumed only in terms of the probability that the available strength will be adequate to withstand the lifetime maximum load. A spatial interpolation approach was ...

  6. Implementations of BLAST for parallel computers.

    Science.gov (United States)

    Jülich, A

    1995-02-01

    The BLAST sequence comparison programs have been ported to a variety of parallel computers-the shared memory machine Cray Y-MP 8/864 and the distributed memory architectures Intel iPSC/860 and nCUBE. Additionally, the programs were ported to run on workstation clusters. We explain the parallelization techniques and consider the pros and cons of these methods. The BLAST programs are very well suited for parallelization for a moderate number of processors. We illustrate our results using the program blastp as an example. As input data for blastp, a 799 residue protein query sequence and the protein database PIR were used.

  7. Modeling of Near-Field Blast Performance

    Science.gov (United States)

    2013-11-01

    Army Research Laboratory Modeling of Near-Field Blast Performance by Barrie E. Homan , Matthew M. Biss, and Kevin L. McNesby ARL-TR-6711 November 2013...Laboratory Aberdeen Proving Ground, MD 21005-5066 ARL-TR-6711 November 2013 Modeling of Near-Field Blast Performance Barrie E. Homan , Matthew M. Biss, and... Homan Matthew M. Biss Kevin L. McNesby U.S. Army Research Laboratory ATTN: RDRL-WMP-G Aberdeen Proving Ground, MD 21005-5066 Two hydrocode packages

  8. Neuro-Glial and Systemic Mechanisms of Pathological Responses in Rat Models of Primary Blast Overpressure Compared to “Composite” Blast

    Science.gov (United States)

    Svetlov, Stanislav I.; Prima, Victor; Glushakova, Olena; Svetlov, Artem; Kirk, Daniel R.; Gutierrez, Hector; Serebruany, Victor L.; Curley, Kenneth C.; Wang, Kevin K. W.; Hayes, Ronald L.

    2012-01-01

    A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position toward blast generated by an external shock tube. In this study, we further characterized blast producing moderate traumatic brain injury and defined “composite” blast and primary blast exposure set-ups. Schlieren optics visualized interaction between the head and a shock wave generated by external shock tube, revealing strong head acceleration upon positioning the rat on-axis with the shock tube (composite blast), but negligible skull movement upon peak overpressure exposure off-axis (primary blast). Brain injury signatures of a primary blast hitting the frontal head were assessed and compared to damage produced by composite blast. Low to negligible levels of neurodegeneration were found following primary blast compared to composite blast by silver staining. However, persistent gliosis in hippocampus and accumulation of GFAP/CNPase in circulation was detected after both primary and composite blast. Also, markers of vascular/endothelial inflammation integrin alpha/beta, soluble intercellular adhesion molecule-1, and L-selectin along with neurotrophic factor nerve growth factor-beta were increased in serum within 6 h post-blasts and persisted for 7 days thereafter. In contrast, systemic IL-1, IL-10, fractalkine, neuroendocrine peptide Orexin A, and VEGF receptor Neuropilin-2 (NRP-2) were raised predominantly after primary blast exposure. In conclusion, biomarkers of major pathological pathways were elevated at all blast set-ups. The most significant and persistent changes in neuro-glial markers were found after composite blast, while primary blast instigated prominent systemic cytokine/chemokine, Orexin A, and Neuropilin-2 release

  9. Neuro-glial and systemic mechanisms of pathological responses in rat models of primary blast overpressure compared to ‘composite’ blast.

    Directory of Open Access Journals (Sweden)

    Stanislav I. Svetlov

    2012-02-01

    Full Text Available A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position towards blast generated by an external shock tube. In this study, we further characterized blast producing moderate TBI and defined ‘composite’ blast and primary blast exposure set-ups. Schlieren optics visualized interaction between the head and a shock wave generated by external shock tube, revealing strong head acceleration upon positioning the rat on-axis with the shock tube (composite blast, but negligible skull movement upon peak overpressure exposure off-axis (primary blast. Brain injury signatures of a primary blast hitting the frontal head were assessed and compared to damage produced by composite blast. Low to negligible levels of neurodegeneration were found following primary blast compared to composite blast by silver staining. However, persistent gliosis in hippocampus and accumulation of GFAP/CNPase in circulation was detected after both primary and composite blast. Also, markers of vascular/endothelial inflammation integrin alpha/beta, sICAM, and L-selectin along with neurotrophic factor NGF-beta were increased in serum within 6 hours post-blasts and persisted for 7 days thereafter. In contrast, systemic IL-1, IL-10, fractalkine, neuroendocrine peptide Orexin A, and VEGF receptor Neuropilin-2 (NRP-2 were raised predominantly after primary blast exposure. In conclusion, biomarkers of major pathological pathways were elevated at all blast setups. The most significant and persistent changes in neuro-glial markers were found after composite blast, while primary blast instigated prominent systemic cytokine/chemokine, Orexin A, and Neuropilin-2 release, particularly when primary blast impacted rats with

  10. [The extremely violent child].

    Science.gov (United States)

    Berger, M; Bonneville, E

    2009-02-01

    More and more children have extremely violent behaviour which appears about the age of 15-16 months, when walking makes their hands free. This violence is individual, can appear suddenly at anytime, and is not accompanied by guilt. It is caused by early psychological and repeated traumas, whose importance is usually underestimated: unpredictable, violent parents, exposure to the spectacle of conjugal violence, distortion of the signals emitted by the toddler. These traumas bring about specific psychological structure. The prevention of these troubles exists but is impossible to realise in France.

  11. Extreme Programming Pocket Guide

    CERN Document Server

    Chromatic

    2003-01-01

    Extreme Programming (XP) is a radical new approach to software development that has been accepted quickly because its core practices--the need for constant testing, programming in pairs, inviting customer input, and the communal ownership of code--resonate with developers everywhere. Although many developers feel that XP is rooted in commonsense, its vastly different approach can bring challenges, frustrations, and constant demands on your patience. Unless you've got unlimited time (and who does these days?), you can't always stop to thumb through hundreds of pages to find the piece of info

  12. Mycetoma of lower extremity

    Directory of Open Access Journals (Sweden)

    Sahariah S

    1978-01-01

    Full Text Available Ten cases of mycetoma of the lower extremity were seen and treated at the Postgraduate Institute of Medical Education & Research, Chandigarh, India, during the years 1973 to 1975. Six were treated by conservative method e.g. antibiotics, sulfonamides and immobilization of the part while remaining four were submitted t o surgery. Four out o f six from the first group had recurrence and has been put on second line of therapy. Recurrence occurred in only one case from the second group and he required an above knee amputation while the remaining three are free of disease and are well rehabilitated.

  13. Dynamic loads on human and animal surrogates at different test locations in compressed-gas-driven shock tubes

    Science.gov (United States)

    Alay, E.; Skotak, M.; Misistia, A.; Chandra, N.

    2017-10-01

    Dynamic loads on specimens in live-fire conditions as well as at different locations within and outside compressed-gas-driven shock tubes are determined by both static and total blast overpressure-time pressure pulses. The biomechanical loading on the specimen is determined by surface pressures that combine the effects of static, dynamic, and reflected pressures and specimen geometry. Surface pressure is both space and time dependent; it varies as a function of size, shape, and external contour of the specimens. In this work, we used two sets of specimens: (1) anthropometric dummy head and (2) a surrogate rodent headform instrumented with pressure sensors and subjected them to blast waves in the interior and at the exit of the shock tube. We demonstrate in this work that while inside the shock tube the biomechanical loading as determined by various pressure measures closely aligns with live-fire data and shock wave theory, significant deviations are found when tests are performed outside.

  14. Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2011-01-21

    In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cm from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the front. Because the headform is so close to the charge, it experiences a wave with significant curvature. By contrast, a realistic blast from a 2.2 kg TNT charge ({approx} an uncased 105 mm artillery round) is fatal at an overpressure of 10 atm (4). For an injury level (4) similar to (1), a 2.2 kg charge has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 2.1 atm, 2.3 ms, and 18 psi-ms at the front of the head (250 cm from charge), and 1.8 atm, 2.5 ms, and 16.8 psi-ms at the back of the head (270 cm from charge). The peak pressure decreases by only a factor of 1.2 as it traverses the head. Because the 0.36 ms traversal time is much smaller than the positive phase duration, pressures on the head become relatively uniform when the blast reaches the back of the head. The larger standoff implies

  15. Compliance Monitoring of Underwater Blasting for Rock Removal at Warrior Point, Columbia River Channel Improvement Project, 2009/2010

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J.; Johnson, Gary E.; Woodley, Christa M.; Skalski, J. R.; Seaburg, Adam

    2011-05-10

    The U.S. Army Corps of Engineers, Portland District (USACE) conducted the 20-year Columbia River Channel Improvement Project (CRCIP) to deepen the navigation channel between Portland, Oregon, and the Pacific Ocean to allow transit of fully loaded Panamax ships (100 ft wide, 600 to 700 ft long, and draft 45 to 50 ft). In the vicinity of Warrior Point, between river miles (RM) 87 and 88 near St. Helens, Oregon, the USACE conducted underwater blasting and dredging to remove 300,000 yd3 of a basalt rock formation to reach a depth of 44 ft in the Columbia River navigation channel. The purpose of this report is to document methods and results of the compliance monitoring study for the blasting project at Warrior Point in the Columbia River.

  16. Developments in vapour cloud explosion blast modeling

    NARCIS (Netherlands)

    Mercx, W.P.M.; Berg, A.C. van den; Hayhurst, C.J.; Robertson, N.J.; Moran, K.C.

    2000-01-01

    TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be

  17. Severe tyre blast injuries during servicing.

    Science.gov (United States)

    Hefny, Ashraf F; Eid, Hani O; Abu-Zidan, Fikri M

    2009-05-01

    The destructive potential of the tyre explosions has received little attention in the medical literature. Fatal and severely deforming injuries have been reported. These blasts mainly affect the personnel servicing big vehicle tyres such as trucks and buses. We aimed to review the relevant literature on tyre blast injuries so as to define the mechanism of injury, outcome, and its methods of prevention. A search of the English literature on tyre blast injuries was performed through Medline. Different studies were retrieved, analysed and combined together. A total of 763 patients were studied in the literature. Most of the patients were young aged male mechanics and the explosions usually occur during tyre servicing especially during inflation. Injury is caused by the pressure impact of the explosion or by direct hit of the rim. The head and face are the most commonly affected regions (48%) followed by the upper limbs (20%). About 25% of patients had multi-trauma. The overall mortality is high (19%) and is mainly caused by head injuries. Inflated large tyres contain a tremendous amount of potential energy. Tyre blast injuries during servicing have a high morbidity and mortality. Preventive occupational methods should be implemented.

  18. Gene interactions and genetics of blast resistance and yield ...

    Indian Academy of Sciences (India)

    2014-08-11

    Aug 11, 2014 ... Abstract. Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1,. F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL). CT13432-3R, carrying four blast resistance ...

  19. Gene interactions and genetics of blast resistance and yield ...

    Indian Academy of Sciences (India)

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 ...

  20. Identification and detection of murine leukemia blasts by flow cytometry

    OpenAIRE

    sprotocols

    2015-01-01

    Human leukemia has been determined and classified with the help of flow cytometry for the past two decades. Past attempts to detect leukemia blasts relied on both forward and side scatter (FSC and SSC) based on cell size and granularity. However, this technique failed to show a clean separation of blasts from normal lineage cells. In 1993, Borowitz, et al developed flow cytometric analysis to distinguish human leukemia blasts from other normal lineage cells by using fluorescence-conjugated CD...

  1. Water-Depth-Based Prediction Formula for the Blasting Vibration Velocity of Lighthouse Caused by Underwater Drilling Blasting

    Directory of Open Access Journals (Sweden)

    Wenbin Gu

    2017-01-01

    Full Text Available Lighthouses are the most important hydraulic structures that should be protected during underwater drilling blasting. Thus, the effect of blasting vibration on lighthouse should be studied. On the basis of the dimensional analysis, we deduced a revised formula for water depth based on Sodev’s empirical formula and established the linear fitting model. During the underwater reef project in the main channel of Shipu Harbor in the Ningbo–Zhoushan Port, the blasting vibration data of the lighthouse near the underwater blasting area were monitored. The undetermined coefficient, resolvable coefficient, and F value of the two formulas were then obtained. The comparison of the data obtained from the two formulas showed that they can effectively predict the blasting vibration on the lighthouse. The correction formula that considers water depth can obviously reduce prediction errors and accurately predict blasting vibration.

  2. Plastic Media Blasting - An alternative for coating removal

    Science.gov (United States)

    Abbott, Kenneth E.

    1989-03-01

    Plastic Media Blasting (PMB) is a revolutionary method for the rapid and safe removal of primer, paint and even powder and other chemically resistant coatings from a vast range of products without the use of toxic chemicals or pneumatic blasting with hard abrasives. Although resembling sand-blasting, PMB does not use the hard abrasives or high pressures of that process. Instead, PMB uses reusable plastic particles which are applied at pressures of 20 to 40 psi. The unique abrasive blast media not only replaces potentially hazardous abrasives such as silica sand, but since it is reusable it also generates less overall waste material.

  3. Assessment of Blasting Operations Effects During Highway Tunnel Construction

    Directory of Open Access Journals (Sweden)

    Valašková Veronika

    2015-12-01

    Full Text Available Blasting operations are one of the fundamental parts of daily civil engineering. Drilling and blasting still remain the only possible ways of tunnelling in very adverse geological conditions. However, this method is a source of various disadvantages, the main one being tremors propagating through the geological environment which not only affect buildings, but also disturb the comfort of living in the vicinity of the source. Designing this procedure is mostly done using standardized empirical relations. This article shows the possibility of using a FEM technique in predicting blast effects. This approach is demonstrated in a simple case study on the impact of blasting operations on steel pipes.

  4. Transient changes in neuronal cell membrane permeability after blast exposure.

    Science.gov (United States)

    Arun, Peethambaran; Abu-Taleb, Rania; Valiyaveettil, Manojkumar; Wang, Ying; Long, Joseph B; Nambiar, Madhusoodana P

    2012-04-18

    The biochemical mechanisms of explosive blast-induced traumatic brain injury and the subsequent long-term neurobehavioral abnormalities are still not completely understood. We studied the biochemical mechanism of blast traumatic brain injury using our recently reported in-vitro model system with a shock tube. Primary blast exposure of in-vitro models leads to neurobiological changes in an overpressure dose-dependent and time-dependent manner. Lactate dehydrogenase was released significantly into the extracellular medium without cell death after blast exposure, indicating compromised cell membrane integrity. We further explored the integrity of cell membrane after blast exposure by fluorescent dye uptake/release techniques in SH-SY5Y human neuroblastoma cells. Our data indicate that blast exposure leads to an overpressure-dependent transient increase in the release of preloaded calcein AM into the culture medium with proportional intracellular decrease. Uptake of an extracellular nucleic acid-binding dye TO-PRO-3 iodide was also increased significantly after blast exposure, indicating that the increased molecular transport is bidirectional and nuclear membrane integrity is also affected by blast exposure. These results suggest that blast exposure perturbs the integrity of the neuronal cell membrane, leading to increased bidirectional transport of molecules--a potential mechanism that can lead to traumatic brain injury.

  5. Acceleration from short-duration blast

    Science.gov (United States)

    Ritzel, D. V.; Van Albert, S.; Sajja, V.; Long, J.

    2017-10-01

    The blast-induced motion of spheres has been studied experimentally where the shock wave is rapidly decaying during the period that quasi-steady acceleration would be developed in the case of a step-function shock wave as considered in most shock-tube studies. The motion of sphere models ranging from 39 to 251 mm in diameter and having a range of densities was assessed using the "free-flight" method in a simulator specially designed to replicate the decaying shock wave profile of spherical blast including negative phase and positive entropy gradient. A standardized blast-wave simulation of 125 kPa and 6-ms positive-phase duration was applied for all experiments. In all cases, there are three phases to the motion: a relatively low "kickoff" velocity from the shock diffraction, acceleration or deceleration during the positive duration, then deceleration through the negative phase and subsequent quiescent air. The unexpected deceleration of larger spheres after their kickoff velocity during the decaying yet high-speed flow of the blast wave seems associated with the persistence of a ring vortex on the downstream side of the sphere. The flow is entirely unsteady with initial forces dominated by the shock diffraction; therefore, the early motion of spheres under such conditions is not governed by quasi-steady drag as in classical aerodynamics. The work will help establish scaling rules for model studies of blast-induced motion relevant to improvised explosive devices, and preliminary results are shown for motion imparted to a human skull surrogate.

  6. Stochastic procedures for extreme wave induced responses in flexible ships

    Directory of Open Access Journals (Sweden)

    Jørgen Juncher Jensen

    2014-12-01

    Full Text Available Different procedures for estimation of the extreme global wave hydroelastic responses in ships are discussed. Firstly, stochastic procedures for application in detailed numerical studies (CFD are outlined. The use of the First Order Reliability Method (FORM to generate critical wave episodes of short duration, less than 1 minute, with prescribed probability content is discussed for use in extreme response predictions including hydroelastic behaviour and slamming load events. The possibility of combining FORM results with Monte Carlo simulations is discussed for faster but still very accurate estimation of extreme responses. Secondly, stochastic procedures using measured time series of responses as input are considered. The Peak-over-Threshold procedure and the Weibull fitting are applied and discussed for the extreme value predictions including possible corrections for clustering effects.

  7. Load and Global Response of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    The present monograph covers wave load and global structural response for ships. It is primary written as a textbook for students with an introductionary background in naval architecture and a basic knowledge of statistics and strength of materials. The subjects are treated in details starting from...... first principles. The aim has been to derive and present the necessary theoretical framework for predicting the extreme loads and the corresponding hull girder stresses the ship may be subjected to during its operational lifetime.Although some account is given to reliabiity analysis, the present...

  8. 22 CFR 121.11 - Military demolition blocks and blasting caps.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Military demolition blocks and blasting caps... blasting caps. Military demolition blocks and blasting caps referred to in Category IV(a) do not include the following articles: (a) Electric squibs. (b) No. 6 and No. 8 blasting caps, including electric...

  9. Hydraulic Soft Yaw System Load Reduction and Prototype Results

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Markussen, Kristian

    2013-01-01

    Introducing a hydraulic soft yaw concept for wind turbines leads to significant load reductions in the wind turbine structure. The soft yaw system operates as a shock absorption system on a car, hence absorbing the loading from turbulent wind conditions instead of leading them into the stiff wind...... turbine structure. Results presented shows fatigue reductions of up to 40% and ultimate load reduction of up to 19%. The ultimate load reduction increases even more when the over load protection system in the hydraulic soft yaw system is introduced and results show how the exact extreme load cut off...... operates. Further it is analyzed how the soft yaw system influence the power production of the turbine. It is shown that the influence is minimal, but at larger yaw errors the effect is possitive. Due to the implemeted functions in the hydraulic soft yaw system such as even load distribution on the pinions...

  10. Lower extremity injuries in snowboarding.

    Science.gov (United States)

    Ishimaru, Daichi; Ogawa, Hiroyasu; Sumi, Hiroshi; Sumi, Yasuhiko; Shimizu, Katsuji

    2011-03-01

    In snowboarding, the upper extremity is known as the most common injury site and little information is available for lower extremity injuries. Here, we aim to discuss lower extremity injuries during snowboarding. We retrospectively analyzed the epidemiologic factors, injury types, and injury mechanisms for injured snowboarders (7,793 cases) between 2004-2005 and 2008-2009 seasons; information was gathered via questionnaires. Individuals were classified into a lower extremity injury group (961 cases) and a control group with other injuries (6,832 cases). The incidence of lower extremity injuries in snowboarding was 0.16 per 1,000 participant days, accounting for 12.3% of all snowboarding injuries. The mean age of the lower extremity injury group and injured control group was 26.1 years ± 5.9 years and 25.1 years ± 5.6 years, respectively. Approximately 90% of snowboarders in both the groups were equipped with soft-shelled boots. Skilled snowboarders tended to sustain lower extremity injuries (psnowboarding is lacerations/contusions caused by collision with other snow sport participants. Lower extremity injuries in snowboarding differ considerably from well-known upper extremity injuries in terms of injury types and mechanisms. The incidence of lower extremity injuries is high and deserves further attention. Copyright © 2011 by Lippincott Williams & Wilkins

  11. Evaluation of Novel Polyunsaturated Fatty Acid Derived Lipid Mediators of Inflammation to Ameliorate the Deleterious Effects of Blast Overpressure on Eye and Brain Visual Processing Centers in Rats

    Science.gov (United States)

    2014-10-01

    loaded sled is inserted down the barrel of a compressed air driven shock tube to a preset position in its forward expansion chamber . The unawake...deliver 20 psi 6 of air to the rat’s position, as clamped between the rear compression and forward expansion chambers . The blast wave travels...damage, since bloody froth was issuing from its nose. This yields a mortality incidence of 2%, which is considerably lower than the 20% death rate that

  12. Carbohydrate-Loading Diet

    Science.gov (United States)

    ... of your calories from carbohydrates. The role of carbohydrates Carbohydrates, also known as starches and sugars, are ... to consume some energy sources during your event. Carbohydrate loading Carbohydrate loading is done the week before ...

  13. Survival risk assessment for primary blast exposures to the head.

    Science.gov (United States)

    Rafaels, Karin; Bass, Cameron R Dale; Salzar, Robert S; Panzer, Matthew B; Woods, William; Feldman, Sanford; Cummings, Thomas; Capehart, Bruce

    2011-11-01

    Many soldiers returning from the current conflicts in Iraq and Afghanistan have had at least one exposure to an explosive event and a significant number have symptoms consistent with traumatic brain injury. Although blast injury risk functions have been determined and validated for pulmonary injury, there is little information on the blast levels necessary to cause blast brain injury. Anesthetized male New Zealand White rabbits were exposed to varying levels of shock tube blast exposure focused on the head, while their thoraces were protected. The specimens were euthanized and evaluated when the blast resulted in respiratory arrest that was non-responsive to resuscitation or at 4?h post-exposure. Injury was evaluated by gross examination and histological evaluation. The fatality data from brain injury were then analyzed using Fisher's exact test to determine a brain fatality risk function. Greater blast intensity was associated with post-blast apnea and the need for mechanical ventilation. Gross examination revealed multifocal subdural hemorrhages, most often near the brainstem, at more intense levels of exposure. Histological evaluation revealed subdural and subarachnoid hemorrhages in the non-responsive respiratory-arrested specimens. A fatality risk function from blast exposure to the head was determined for the rabbit specimens with an LD(50) at a peak overpressure of 750?kPa. Scaling techniques were used to predict injury risk at other blast overpressure/duration combinations. The fatality risk function showed that the blast level needed to cause fatality from an overpressure wave exposure to the head was greater than the peak overpressure needed to cause fatality from pulmonary injury. This risk function can be used to guide future research for blast brain injury by providing a realistic fatality risk to guide the design of protection or to evaluate injury.

  14. Estimation of Extreme Wind Speeds by Using Mixed Distributions

    Directory of Open Access Journals (Sweden)

    Escalante-Sandoval Carlos Agustín

    2013-04-01

    Full Text Available Structures are designed with the intention of safely withstanding ordinary and extreme wind loads over the entire intended economic lifetime. Due to the fact that extreme wind speeds are essentially random, appropriate statistical procedures needed to be developed in order design more accurately wind-sensitive structures. Five mixed extreme value distributions, with Gumbel, reverse Weibull and General Extreme Value components along with the Two Component Extreme Value distribution were used to model extreme wind speeds. The general procedure to estimate their parameters based on the maximum likelihood method is presented in the paper. A total of 45 sets, ranging from 9-year to 56-year, of largest annual wind speeds gathered from stations located in The Netherlands were fitted to mixed distributions. The best model was selected based on a goodness-of-fit test. The return levels were estimated and compared with those obtained by assuming the data arise from a single distribution. 87% of analyzed samples were better fitted with a mixed distribution. The best mixed models were the mixed reverse Weibull distribution and the mixture Gumbel-Reverse Weibull. Results suggest that it is very important to consider the mixed distributions as an additional mathematical tool when analyzing extreme wind speeds.

  15. Detectors in Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Blaj, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carini, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carron, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Haller, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hart, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hasi, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Herrmann, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kenney, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Segal, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tomada, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-06

    Free Electron Lasers opened a new window on imaging the motion of atoms and molecules. At SLAC, FEL experiments are performed at LCLS using 120Hz pulses with 1012 - 1013 photons in 10 femtoseconds (billions of times brighter than the most powerful synchrotrons). This extreme detection environment raises unique challenges, from obvious to surprising. Radiation damage is a constant threat due to accidental exposure to insufficiently attenuated beam, focused beam and formation of ice crystals reflecting the beam onto the detector. Often high power optical lasers are also used (e.g., 25TW), increasing the risk of damage or impeding data acquisition through electromagnetic pulses (EMP). The sample can contaminate the detector surface or even produce shrapnel damage. Some experiments require ultra high vacuum (UHV) with strict design, surface contamination and cooling requirements - also for detectors. The setup is often changed between or during experiments with short turnaround times, risking mechanical and ESD damage, requiring work planning, training of operators and sometimes continuous participation of the LCLS Detector Group in the experiments. The detectors used most often at LCLS are CSPAD cameras for hard x-rays and pnCCDs for soft x-rays.

  16. Windows .NET Network Distributed Basic Local Alignment Search Toolkit (W.ND-BLAST)

    Science.gov (United States)

    Dowd, Scot E; Zaragoza, Joaquin; Rodriguez, Javier R; Oliver, Melvin J; Payton, Paxton R

    2005-01-01

    Background BLAST is one of the most common and useful tools for Genetic Research. This paper describes a software application we have termed Windows .NET Distributed Basic Local Alignment Search Toolkit (W.ND-BLAST), which enhances the BLAST utility by improving usability, fault recovery, and scalability in a Windows desktop environment. Our goal was to develop an easy to use, fault tolerant, high-throughput BLAST solution that incorporates a comprehensive BLAST result viewer with curation and annotation functionality. Results W.ND-BLAST is a comprehensive Windows-based software toolkit that targets researchers, including those with minimal computer skills, and provides the ability increase the performance of BLAST by distributing BLAST queries to any number of Windows based machines across local area networks (LAN). W.ND-BLAST provides intuitive Graphic User Interfaces (GUI) for BLAST database creation, BLAST execution, BLAST output evaluation and BLAST result exportation. This software also provides several layers of fault tolerance and fault recovery to prevent loss of data if nodes or master machines fail. This paper lays out the functionality of W.ND-BLAST. W.ND-BLAST displays close to 100% performance efficiency when distributing tasks to 12 remote computers of the same performance class. A high throughput BLAST job which took 662.68 minutes (11 hours) on one average machine was completed in 44.97 minutes when distributed to 17 nodes, which included lower performance class machines. Finally, there is a comprehensive high-throughput BLAST Output Viewer (BOV) and Annotation Engine components, which provides comprehensive exportation of BLAST hits to text files, annotated fasta files, tables, or association files. Conclusion W.ND-BLAST provides an interactive tool that allows scientists to easily utilizing their available computing resources for high throughput and comprehensive sequence analyses. The install package for W.ND-BLAST is freely downloadable from

  17. Likelihood estimators for multivariate extremes

    KAUST Repository

    Huser, Raphaël

    2015-11-17

    The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model.

  18. Sixty-four-slice CT angiography to determine the three dimensional relationships of vascular and soft tissue wounds in lower extremity war time injuries.

    Science.gov (United States)

    Smith, Jennifer M; Fox, Charles J; Brazaitis, Michael P; Via, Kathy; Garcia, Roman; Feuerstein, Irwin M

    2010-01-01

    This article analyzes the use and benefits of the 64-slice CT scanner in determining the 3D relationships of vascular and soft tissue wounds in lower extremity war time injuries. A brief overview of CT scanning is given as well as the techniques used to produce the images needed for diagnosis. The series follows two similar cases of war time injury patients at the Walter Reed Army Medical Center. The first case is a 30-year-old active duty male, who presented with multiple trauma from a motor vehicle accident because of an improvised explosive device (IED) blast, sustaining substantial lower extremity injuries. The second case is a 34-year-old active duty male, who presented with multiple trauma blast injuries. Both cases were of interest because the vasculature was found to be very close to the surface of the wound, which put the arteries at risk for rupture and for iatrogenic injury during repeated debridements.

  19. ExtremeBounds: Extreme Bounds Analysis in R

    Directory of Open Access Journals (Sweden)

    Marek Hlavac

    2016-08-01

    Full Text Available This article introduces the R package ExtremeBounds to perform extreme bounds analysis (EBA, a sensitivity test that examines how robustly the dependent variable of a regression model is related to a variety of possible determinants. ExtremeBounds supports Leamer's EBA that focuses on the upper and lower extreme bounds of regression coefficients, as well as Sala-i-Martin's EBA which considers their entire distribution. In contrast to existing alternatives, it can estimate models of a variety of user-defined sizes, use regression models other than ordinary least squares, incorporate non-linearities in the model specification, and apply custom weights and standard errors. To alleviate concerns about the multicollinearity and conceptual overlap of examined variables, ExtremeBounds allows users to specify sets of mutually exclusive variables, and can restrict the analysis to coefficients from regression models that yield a variance inflation factor within a prespecified limit.

  20. Spatial electric load forecasting

    CERN Document Server

    Willis, H Lee

    2002-01-01

    Spatial Electric Load Forecasting Consumer Demand for Power and ReliabilityCoincidence and Load BehaviorLoad Curve and End-Use ModelingWeather and Electric LoadWeather Design Criteria and Forecast NormalizationSpatial Load Growth BehaviorSpatial Forecast Accuracy and Error MeasuresTrending MethodsSimulation Method: Basic ConceptsA Detailed Look at the Simulation MethodBasics of Computerized SimulationAnalytical Building Blocks for Spatial SimulationAdvanced Elements of Computerized SimulationHybrid Trending-Simulation MethodsAdvanced

  1. Cognitive Load and Cooperation

    DEFF Research Database (Denmark)

    Døssing, Felix Sebastian; Piovesan, Marco; Wengström, Erik Roland

    2017-01-01

    We study the effect of intuitive and reflective processes on cooperation using cognitive load. Compared with time constraint, which has been used in the previous literature, cognitive load is a more direct way to block reflective processes, and thus a more suitable way to study the link between...... intuition and cooperation. Using a repeated public goods game, we study the effect of different levels of cognitive load on contributions. We show that a higher cognitive load increases the initial level of cooperation. In particular, subjects are significantly less likely to fully free ride under high...... cognitive load....

  2. Methodology of Testing Shot Blasting Machines in Industrial Conditions

    Directory of Open Access Journals (Sweden)

    R. Wrona

    2012-04-01

    Full Text Available Shot blasting machines are widely used for automated surface treatment and finishing of castings. In shot blasting processes the stream of shots is generated and shaped by blasting turbines, making up a kinetic and dynamic system comprising a separating rotor, an adapting sleeve and a propelling rotor provided with blades. The shot blasting performance- i.e. the quality of shot treated surfaces depends on the actual design and operational parameters of the unit whilst the values of relevant parameters are associated with the geometry of turbine components and the level of its integration with the separator system. The circulation of the blasting medium becomes the integrating factor of the process line, starting from the hopper, through the propeller turbine, casting treatment, separation of contaminated abrasive mixture, to its recycling and reuse.Inferior quality of the abrasive agent (shot and insufficient purity of the abrasive mixture are responsible for low effectiveness of shot blasting. However, most practitioners fail to fully recognise the importance of proper diagnostics of the shot blasting process in industrial conditions. The wearing of major machine components and of the blasting agent and quality of shot treated surfaces are often misinterpreted, hence the need to take into account all factors involved in the process within the frame of a comprehensive methodology.This paper is an attempt to formulate and apply the available testing methods to the engineering practice in industrial conditions.

  3. Dry ice blasting for the conservation cleaning of metals

    NARCIS (Netherlands)

    van der Molen, R.; Joosten, I.; Beentjes, T.; Megens, L.; Mardikian, P.; Chemello, C.; Watters, C.; Hull, P.

    2011-01-01

    This research was carried out to assess the feasibility of dry ice blasting as a replacement for solvent cleaning for the removal of organic layers from metal cultural heritage objects. The effects of dry ice blasting on test samples of aluminium, bronze and weathering steel were studied along with

  4. Blasting Standards for the Ghanaian Mining Industry | Amegbey ...

    African Journals Online (AJOL)

    Ghana is a well known mining nation and hard rock mining has been going on since the 10th century. Mining companies in Ghana are well aware of the regulatory requirements to carry out blasting activities such that neighbouring communities are protected from excessive impact as a result of blast vibrations amongst other ...

  5. Identification of blast resistance expression in rice genotypes using ...

    African Journals Online (AJOL)

    Markers OPA-05, OPF-06, OPF-09, OPF-17, OPG-17, OPG-18, OPG-19, OPH-18, OPK-12, P-265-550 and P-286-350 found linked to blast resistance in most of the resistant genotypes could be considered as potent molecular markers in the selection of blast resistant genotypes. Amplification with RAPD and SCAR primers ...

  6. Testing the blast wave model with Swift GRBs

    NARCIS (Netherlands)

    Curran, P.A.; Starling, R.L.C.; van der Horst, A.J.; Wijers, R.A.M.J.

    2009-01-01

    The complex structure of the light curves of Swift Gamma-Ray Bursts (GRBs) has made the identification of breaks, and the interpretation of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to identify breaks, which are possibly hidden, and to constrain the blast

  7. Testing the blast wave model with Swift GRBs

    NARCIS (Netherlands)

    Curran, P.A.; Starling, R.L.C.; van der Horst, A.J.; Wijers, R.A.M.J.; de Pasquale, M.; Page, M.

    2011-01-01

    The complex structure of the light curves of Swift GRBs (e.g. superimposed flares and shallow decay) has made their interpretation and that of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to constrain the blast wave parameters: electron energy distribution, p,

  8. Genetic diversity of the blast fungus, Magnaporthe grisea (Hebert ...

    African Journals Online (AJOL)

    Genetic diversity of the blast fungus, Magnaporthe grisea (Hebert) Barr, in Burkina Faso. Y Séré, A Onasanya, A Afolabi, HD Mignouna, K Akator. Abstract. Trapping nurseries trialed at two screening sites in Burkina Faso appeared to be an effective tool to characterize the virulence spectrum of blast populations using limited ...

  9. Temporal Progression of Visual Injury from Blast Exposure

    Science.gov (United States)

    2017-09-01

    assesment was present in both left and right eyes, but was more pronounced in the directly exposed right eye. 8 Computational Studies. Reducing...seen throughout the duration of the study. To correlate experimental blast exposures in rodents to human blast exposures, a computational parametric...relationship. Progress and Accomplishments This year was focused on histological analysis, computational simulation, and publication. All histology

  10. Implementation of a user defined mine blast model in LSDYNA

    NARCIS (Netherlands)

    Tyler-Street, M.; Leerdam, P.J.C.

    2012-01-01

    A user defined mine blast model has been developed and implemented into the explicit finite element code LS-DYNA to provide a numerically efficient method for simulating an antivehicular mine blast. The objective is to provide a simple and robust numerical method which is able to represent both the

  11. Identification of blast resistance expression in rice genotypes using ...

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... Pathogen variability and host resistance in rice blast disease. Phytopathology 18: 167-187. Kumar et al. 3509. Padmanabhan (1965). Identification of Pathogen races of Pyricularia oryzae in India. Phytopathology 60: 1574. Pengyuan (2004). Systematic acquired resistance against blast disease infection.

  12. Extreme Environments: Why NASA?

    Science.gov (United States)

    Meyer, M. A.

    2002-12-01

    Life on our planet is the only known example in the universe and so we are relegated to this planet for the study of life. However, life may be a natural consequence of planet formation, and so the study of the origin, evolution, distribution and future of life may be greatly informed by planetary exploration. Astrobiology has adopted several approaches to study life on Earth, for deducing our origins, for determining the likelihood of life elsewhere, and for enabling the search for evidence of past or present life. The first approach has been the Exobiology Program, centered around understanding the origins of life and which supports individual investigator research. Second has been the construction of consortia-type research in which researchers from different disciplines focus on a larger problem. This structure began with NASA Specialized Centers of Research and Training and has grown to include the Astrobiology Institute - a collection of competitively selected groups of researchers attacking problems in Astrobiology as individual teams and as a consolidated Institute. With the formation of an intellectual basis for exploring for life elsewhere, Astrobiology has initiated the competitive research and development program in instrument development (Astrobiology Science and Technology for Instrument Development [ASTID] Program) that would enable future mission instruments for the exploration of planetary bodies in the search for prebiotic chemistry, habitable environments (past or present), biomarkers, and possibly life itself. However, the act of exploring requires robust instrumentation, mobile robotic platforms, efficient operations, and a high level of autonomy. To this end, Astrobiology has started a new research activity that promotes scientifically-driven robotic exploration of extreme environments on Earth that are analogous to suspected habitable environments on other planetary bodies. The program is called Astrobiology Science and Technology for

  13. The Biology of CML blast crisis.

    Science.gov (United States)

    Radich, Jerald P

    2007-01-01

    The natural history of chronic myeloid leukemia (CML) progresses from a relatively benign chronic phase into a fatal blast crisis, which resembles acute leukemia, but is incurable by chemotherapy. Fortunately, the progression can usually be blocked by tyrosine kinase therapy or allogeneic transplantation. The seemingly stereotypical march of progression involves changes in genetic instability and DNA repair, proliferation, differentiation, and apoptosis, and thus may serve as a unique model of cancer evolution and progression. Given that all treatments work much better in chronic-phase than advanced-phase disease, the clinical dilemma is predicting and detecting patients bound to evolve into advanced disease. This is especially important in the age of tyrosine kinase inhibition (TKI) therapy. The purpose of this review is to address the biology of blast crisis in the age of tyrosine kinase therapy, with an emphasis on what genes or pathways may be future targets of predictive assays or treatments of progression.

  14. Attenuation of strong external blast by foam barriers

    Science.gov (United States)

    Sembian, S.; Liverts, M.; Apazidis, N.

    2016-09-01

    The mitigation of externally generated strong blast waves by an aqueous foam barrier of varying configurations within fixed distance between the explosion origin and the object to be protected is investigated and quantified both experimentally and numerically. The blast waves of shock Mach number 4.8 at 190 mm from the explosion plane are generated using exploding wire technique. The initially cylindrical blast waves are transformed into a plane blast wave in a specially constructed test unit in which the experiments are performed. The shock waves emanating from the foam barrier are captured using shadowgraph technique. A simple numerical model treating the foam by a pseudo-gas approach is used in interpreting and re-constructing the experimental results. The additional contribution of the impedance mismatch factor is analysed with the aid of numerical simulation and exploited for achieving greater blast wave pressure reduction.

  15. High-speed measurement of firearm primer blast waves

    CERN Document Server

    Courtney, Michael; Eng, Jonathan; Courtney, Amy

    2012-01-01

    This article describes a method and results for direct high-speed measurements of firearm primer blast waves employing a high-speed pressure transducer located at the muzzle to record the blast pressure wave produced by primer ignition. Key findings are: 1) Most of the lead styphnate based primer models tested show 5.2-11.3% standard deviation in the magnitudes of their peak pressure. 2) In contrast, lead-free diazodinitrophenol (DDNP) based primers had standard deviations of the peak blast pressure of 8.2-25.0%. 3) Combined with smaller blast waves, these large variations in peak blast pressure of DDNP-based primers led to delayed ignition and failure to fire in brief field tests.

  16. A Table-top Blast Driven Shock Tube

    CERN Document Server

    Courtney, Michael; 10.1063/1.3518970

    2011-01-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer which explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  17. SURFACE PREPARATION OF STEEL SUBSTRATES USING GRIT-BLASTING

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; D. J. Varacalle, Jr.; D. Deason; W. Rhodaberger; E. Sampson

    2005-05-01

    The primary purpose of grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents statistically designed experiments that were accomplished to investigate the effect of abrasives on roughness for A36/1020 steel. The experiments were conducted using a Box statistical design of experiment (SDE) approach. Three grit blasting parameters and their effect on the resultant substrate roughness were investigated. These include blast media, blast pressure, and working distance. The substrates were characterized for roughness using surface profilometry. These attributes were correlated with the changes in operating parameters. Twin-Wire Electric Arc (TWEA) coatings of aluminum and zinc/aluminum were deposited on the grit-blasted substrates. These coatings were then tested for bond strength. Bond strength studies were conducted utilizing a portable adhesion tester following ASTM standard D4541.

  18. The past and present of blast injury research in China.

    Science.gov (United States)

    Zhao, Yan; Zhou, Yuan-Guo

    2015-01-01

    With the increasing incidence of blast injury, the research on its mechanisms and protective measures draws more and more attention. Blast injury has many characteristics different from general war injuries or trauma. For example, soldiers often have various degrees of visceral injury without significant surface damage, combined injuries and arterial air embolism. Researchers in China began to investigate blast injury later than the United States and Sweden, but the development is so fast that lots of achievements have been gained, including the development of biological shock tube, the mechanisms and characteristics of blast injury in various organs, as well as protective measures under special environments. This article reviews the past and current situation of blast injury research in China.

  19. Note: A table-top blast driven shock tube

    Science.gov (United States)

    Courtney, Michael W.; Courtney, Amy C.

    2010-12-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer that explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  20. Lower limb loading in step aerobic dance.

    Science.gov (United States)

    Wu, H-W; Hsieh, H-M; Chang, Y-W; Wang, L-H

    2012-11-01

    Participation in aerobic dance is associated with a number of lower extremity injuries, and abnormal joint loading seems to be a factor in these. However, information on joint loading is limited. The purpose of this study was to investigate the kinetics of the lower extremity in step aerobic dance and to compare the differences of high-impact and low-impact step aerobic dance in 4 aerobic movements (mambo, kick, L step and leg curl). 18 subjects were recruited for this study. High-impact aerobic dance requires a significantly greater range of motion, joint force and joint moment than low-impact step aerobic dance. The peak joint forces and moments in high-impact step aerobic dance were found to be 1.4 times higher than in low-impact step aerobic dance. Understanding the nature of joint loading may help choreographers develop dance combinations that are less injury-prone. Furthermore, increased knowledge about joint loading may be helpful in lowering the risk of injuries in aerobic dance instructors and students. © Georg Thieme Verlag KG Stuttgart · New York.