Science.gov

Sample records for air blast loading

  1. Numerical Simulations of Blast Loads from Near-Field Ground Explosions in Air

    NASA Astrophysics Data System (ADS)

    Dobrociński, Stanisław; Flis, Leszek

    2015-12-01

    Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.

  2. Shape Optimization of Plates to Mitigate the Effects of Air Blast Loading

    DTIC Science & Technology

    2009-06-21

    has been given to analysis of metallic and composite panels, subject to both blast and ballistic loads. Regarding designing for impact mitigation...water. Yen, Skaags and Cheeseman [5] present an experimentally validated dynamic analysis procedure utilizing Ls- Dyna and the ConWep air blast function...orientations in a laminated composite to absorb energy while maintaining stiffness. Further details on effectiveness of blast mitigation solutions in a

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Cerebrovascular Injury in Blast Loading

    DTIC Science & Technology

    2010-01-01

    TITLE: Cerebrovascular injury in blast loading PRINCIPAL INVESTIGATOR: Kenneth L. Monson, PhD...SUBTITLE Cerebrovascular injury in blast loading 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6...and pH control. 15. SUBJECT TERMS Blast brain injury; cerebrovascular injury and dysfunction; shock tube 16. SECURITY CLASSIFICATION OF: 17

  5. Crumb Rubber-Concrete Panels Under Blast Loads

    DTIC Science & Technology

    2010-05-01

    AFRL-RX-TY-TP-2010-0052 CRUMB RUBBER -CONCRETE PANELS UNDER BLAST LOADS PREPRINT Bryan T. Bewick Air Force Research Laboratory 139...JAN-2009 -- 12-MAY-2010 Crumb Rubber -Concrete Panels Under Blast Loads FA4819-09-C-0032 62102F 4918 F0 Q210FA72 *Bewick, Bryan T.; #Salim, Hani A...those without any rubber . concrete; crumb rubber ; energy absorption; static resistance; blast U U U UU 14 Paul Sheppard Reset 1 Crumb Rubber

  6. Performance of Steel Stud Walls Subjected to Blast Loads

    DTIC Science & Technology

    2010-02-01

    20, 2006, St. Louis, MO, USA. Grumbach, Steven D., Clay Naito, and Robert J. Dinan (2007). “Use of Precast Concrete Walls for Protection of Steel...AFRL-RX-TY-TP-2010-0012 PREPRINT PERFORMANCE OF STEEL STUD WALLS SUBJECTED TO BLAST LOADS Bryan Bewick Air Force Research Laboratory...Performance of Steel Stud Walls Subjected to Blast Loads (PREPRINT) FA4819-09-C-0032 62012F 4918 C1 Q103013 +Bewick, Bryan; *Hoemann, John

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

    NASA Astrophysics Data System (ADS)

    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

  8. Injury risk prediction from computational simulations of ocular blast loading.

    PubMed

    Weaver, Ashley A; Stitzel, Sarah M; Stitzel, Joel D

    2017-04-01

    A predictive Lagrangian-Eulerian finite element eye model was used to analyze 2.27 and 0.45 kg trinitrotoluene equivalent blasts detonated from 24 different locations. Free air and ground level blasts were simulated directly in front of the eye and at lateral offset locations with box, average, less protective, and more protective orbital anthropometries, resulting in 96 simulations. Injury risk curves were developed for hyphema, lens dislocation, retinal damage, and globe rupture from experimental and computational data to compute risk from corneoscleral stress and intra-ocular pressure computational outputs. Corneoscleral stress, intra-ocular pressure, and injury risks increased when the blast size was larger and located nearer to the eye. Risks ranged from 20-100 % for hyphema, 1-100 % for lens dislocation, 2-100 % for retinal damage, and 0-98 % for globe rupture depending on the blast condition. Orbital geometry affected the stresses, pressures, and associated ocular injury risks of the blast conditions simulated. Orbital geometries that more fully surrounded the eye such as the more protective orbit tended to produce higher corneoscleral stresses and compression of the eye against the surrounding rigid orbit contributing to high stresses as the blast wave propagated. However, the more protective orbit tended to produce lower intra-ocular pressures in comparison with the other three orbital geometries which may indicate that the more protective orbit inhibits propagation of the blast wave and reduces ocular loading. Results of this parametric computational study of ocular blast loading are valuable to the design of eye protection equipment and the mitigation of blast-related eye injuries.

  9. Air Blast Calculations

    DTIC Science & Technology

    2013-07-01

    library. A Jones-Wilkins-Lee (JWL) equation of state is used for each explosive considered, and a Sesame tabular equation of state is used to model the...explosives investigated (TNT, C4, PBXN-109, and NM) and the CTH material library parameters were used for each. Air was modeled using the Sesame tabular

  10. Effectiveness of eye armor during blast loading.

    PubMed

    Bailoor, Shantanu; Bhardwaj, Rajneesh; Nguyen, Thao D

    2015-11-01

    Ocular trauma is one of the most common types of combat injuries resulting from the interaction of military personnel with improvised explosive devices. Ocular blast injury mechanisms are complex, and trauma may occur through various injury mechanisms. However, primary blast injuries (PBI) are an important cause of ocular trauma that may go unnoticed and result in significant damage to internal ocular tissues and visual impairment. Further, the effectiveness of commonly employed eye armor, designed for ballistic and laser protection, in lessening the severity of adverse blast overpressures (BOP) is unknown. In this paper, we employed a three-dimensional (3D) fluid-structure interaction computational model for assessing effectiveness of the eye armor during blast loading on human eyes and validated results against free field blast measurements by Bentz and Grimm (2013). Numerical simulations show that the blast waves focused on the ocular region because of reflections from surrounding facial features and resulted in considerable increase in BOP. We evaluated the effectiveness of spectacles and goggles in mitigating the pressure loading using the computational model. Our results corroborate experimental measurements showing that the goggles were more effective than spectacles in mitigating BOP loading on the eye. Numerical results confirmed that the goggles significantly reduced blast wave penetration in the space between the armor and the eyes and provided larger clearance space for blast wave expansion after penetration than the spectacles. The spectacles as well as the goggles were more effective in reducing reflected BOP at higher charge mass because of the larger decrease in dynamic pressures after the impact. The goggles provided greater benefit of reducing the peak pressure than the spectacles for lower charge mass. However, the goggles resulted in moderate, sustained elevated pressure loading on the eye, that became 50-100% larger than the pressure loading

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Modelling human eye under blast loading.

    PubMed

    Esposito, L; Clemente, C; Bonora, N; Rossi, T

    2015-01-01

    Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.

  13. Evaluating the Effectiveness of Various Blast Loading Descriptors as Occupant Injury Predictors for Underbody Blast Events

    DTIC Science & Technology

    2013-08-22

    Trembelay, J., “Validation of a Loading Model for Simulating Blast Mine Effects on Armoured Vehicles,” 7th International LS - DYNA Users Conference... blast incidents, followed by tibia and lower leg injuries. To support the design and development of Mine -Resistant Ambush Protected (MRAP) military...ground vehicles, mine blast underbody hull kits and mine blast seats, a suite of underbody modeling methods were quickly developed [4- 11]. These

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

    SciTech Connect

    Not Available

    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.

  15. The effect of explosive blast loading on human neuroblastoma cells.

    PubMed

    Zander, Nicole E; Piehler, Thuvan; Banton, Rohan; Boggs, Mary

    2016-07-01

    Diagnosis of mild to moderate traumatic brain injury is challenging because brain tissue damage progresses slowly and is not readily detectable by conventional imaging techniques. We have developed a novel in vitro model to study primary blast loading on dissociated neurons using nitroamine explosives such as those used on the battlefield. Human neuroblastoma cells were exposed to single and triple 50-psi explosive blasts and single 100-psi blasts. Changes in membrane permeability and oxidative stress showed a significant increase for the single and triple 100-psi blast conditions compared with single 50-psi blast and controls. Published by Elsevier Inc.

  16. Baryon Loaded Relativistic Blast Waves in Supernovae

    NASA Astrophysics Data System (ADS)

    Chakraborti, Sayan; Ray, Alak

    2011-03-01

    We provide a new analytic blast wave solution which generalizes the Blandford-McKee solution to arbitrary ejecta masses and Lorentz factors. Until recently relativistic supernovae have been discovered only through their association with long-duration gamma-ray bursts (GRBs). The blast waves of such explosions are well described by the Blandford-McKee (in the ultra-relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows, as the ejecta mass is negligible in comparison to the swept-up mass. The recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, opens up the possibility of highly baryon loaded, mildly relativistic outflows which remains in nearly free-expansion phase during the radio afterglow. In this work, we consider a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating adiabatically due to its collision with the pre-explosion circumstellar wind profile of the progenitor. We compute the synchrotron emission from relativistic electrons in the shock amplified magnetic field. This models the radio emission from the circumstellar interaction of a CEDEX. We show that this model explains the observed radio evolution of the prototypical SN 2009bb and demonstrate that SN 2009bb had a highly baryon loaded, mildly relativistic outflow. We discuss the effect of baryon loading on the dynamics and observational manifestations of a CEDEX. In particular, our predicted angular size of SN 2009bb is consistent with very long baseline interferometric (VLBI) upper limits on day 85, but is presently resolvable on VLBI angular scales, since the relativistic ejecta is still in the nearly free-expansion phase.

  17. Evaluation of five additional enhancements to the building loads analysis and system thermodynamics (BLAST) program. Final report

    SciTech Connect

    Nemeth, R.J.

    1993-04-01

    The Building Loads Analysis and System Thermodynamics (BLAST) energy analysis computer program has undergone a multiyear enhancement program based on feedback and priorities of the BLAST users' group. This project was conducted to evaluate the convenience and applicability of the following BLAST enhancements: Air-to-Air Heat Pump; Expanded Baseboard Heat Options; Report Writer; Thermal Comfort Model. Ice Storage Model; Evaluation responses indicate that the enhancements satisfied users' needs for advanced building energy analysis tools. Although the evaluations revealed program bugs and the lack of documentation in some areas, the programs were easy to install and use. The bugs have been removed and the documentation expanded in the BLAST Users Reference. It is recommended that the enhancements be distributed with future updates and releases of the BLAST program.... BLAST, Enhancements, Energy efficient, Comfort analysis, Technology Transfer Test Bed(T3B).

  18. Evaluating the Effectiveness of Various Blast Loading Descriptors as Occupant Injury Predictors for Underbody Blast Events

    DTIC Science & Technology

    2014-01-09

    Predictors UNCLASSIFIED: Distribution Statement A. Approved for Public Release 4 | P a g e Distribution List  Mr. Sudhakar Arepally ...potentially survivable blast threats in military vehicles” - Sudhakar Arepally , Dr. David Gorsich, Karrie Hope, Stephen Gentner and Kari Dortleff...Sheng and Sudhakar Arepally – Undated TARDEC Brief 27 Unclassified: Distribution Statement A. Approved for public release Blast load descriptors as

  19. Effect of Helmet Pads on the Load Transfer to Head under Blast Loadings

    DTIC Science & Technology

    2015-06-01

    boundary conditions are applied to the head . For longer response duration, appropriate boundary conditions need to be applied to represent the neck ...ARL-RP-0525 ● JUNE 2015 US Army Research Laboratory Effect of Helmet Pads on the Load Transfer to Head under Blast Loadings...ARL-RP-0525 ● JUNE 2015 US Army Research Laboratory Effect of Helmet Pads on the Load Transfer to Head under Blast

  20. 7. Air Blast Circuit Breaker Compressors, view to the southeast. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Air Blast Circuit Breaker Compressors, view to the southeast. The air blast circuit breakers are visible in the left background of the photograph. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

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

    PubMed

    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.

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

    PubMed Central

    Yang, Shu; 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. PMID:25126606

  3. Simulation of the ERDC Blast Load Simulator (BLS) in various test configurations using Loci/BLAST

    NASA Astrophysics Data System (ADS)

    Mord, Clayton T.

    This thesis describes the simulation of ERDC's Blast Load Simulator (BLS) using MSU's Loci/BLAST. The BLS was created to replicate waveforms found in blast scenarios. Loci/BLAST is an explicit, unstructured CFD code that specializes in moving waveforms. ERDC conducted various tests, and a grid for each scenario was created using the SolidMesh tool. Each grid was simulated, and the results were displayed as time history plots and spatial plots. Simulations were also performed that compared 2D and 3D grids and determined the effect of the grate and striker components. There was a strong correlation between the experimental and simulation results for each case, demonstrating that Loci/BLAST is fully capable of modeling the BLS waveforms. A 2D grid produced results comparable to those on a full 3D grid. The grate and striker were critical in the simulation because they significantly affected the waveform.

  4. 7. INTERIOR, STEEL BLAST DOORS, INSTRUMENTATION ROOM. Edwards Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. INTERIOR, STEEL BLAST DOORS, INSTRUMENTATION ROOM. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-4, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  5. A Blast of Cool Air

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Unable to solve their engineering problem with a rotor in their Orbital Vane product, DynEco Corporation turned to Kennedy Space Center for help. KSC engineers determined that the compressor rotor was causing a large concentration of stress, which led to cracking and instant rotor failure. NASA redesigned the lubrication system, which allowed the company to move forward with its compressor that has no rubbing parts. The Orbital Vane is a refrigerant compressor suitable for mobile air conditioning and refrigeration.

  6. Response of marine composites subjected to near field blast loading

    NASA Astrophysics Data System (ADS)

    LiVolsi, Frank

    Experimental studies were performed to understand the explosive response of composite panels when exposed to near-field explosive loading in different environments. The panel construction under consideration was an E-glass fiber-reinforced composite laminate infused with vinyl ester resin (Derakane 8084). The panel was layered bi-axially with plain-woven fiber orientations at 0° and 90°. Panel dimensions were approximately 203 mm x 203 mm x 1 mm (8 in x 8 in x 0.04 in). Experiments were carried out with the panel fully clamped in a holding fixture, which was in turn fastened inside a water tank. The fixture was fastened in such a way as to allow for explosive loading experiments in the following environments: water submersion with water backing, water submersion with air backing, and air immersion with air backing. Experiments were performed in room temperature conditions, and additional experiments in the submerged environments were also performed at high and low water temperatures of 40°C and 0°C, respectively. A stereo Digital Image Correlation (DIC) system was employed to capture the full-field dynamic behavior of the panel during the explosive event. Results indicated that the immersion environment contributes significantly to the blast response of the material and to the specimens' appreciable damage characteristics. The water submersion with air backing environment was found to encourage the greatest panel center point deflection and the most significant damage mechanisms around the boundary. The air immersion with air backing environment was found to encourage less center point deflection and exhibited significant impact damage from the explosive capsule. The water submersion with water backing environment encouraged the least panel deflection and minimal interlaminate damage around the panel boundary and center. Water temperature was found to influence the panel center point deflection, but not damage mechanisms. Maximum positive center point

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

    SciTech Connect

    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.

  8. Failure criteria for blast loads structures. A review

    SciTech Connect

    Longinow, A.; Guralnick, S.A.; Mohammadi, J.

    1982-01-01

    The reliable rating of protective structures in a blast environment depends to a large extent on the ability to predict the magnitude and duration of the blast load required to produce incipient collapse. Such ability is best developed on the basis of experimental data on the failure of structures. At the present time experimental data on this subject is very limited. Also, the field of predicting incipient collapse of structures is mostly in its infancy. This paper briefly reviews the state-of-the-art of predicting the incipient collapse of structures subjected to blast loads and presents a suggested experimental and analytic, probability based program capable of producing the required data and criteria by the use of full-scale tests and model studies. The emphasis of this review is on reinforced concrete structures.

  9. Quarter-scale close-in blast-loading experiments in support of the planned contained firing facility

    SciTech Connect

    Pastrnak, J.W.; Baker, C.F.; Simmons, L.F.

    1994-07-27

    In anticipation of increasingly stringent environmental regulations, Lawrence Livermore National Laboratory is proposing to construct a 60-kg firing chamber to provide blast-effects containment for most of its open-air, high-explosive, firing operations. Even though the Laboratory`s operations are within current environmental limits, containment of the blast effects and hazardous debris will drastically reduce emissions to the environment and minimize the generated hazardous waste. One of the main design considerations is the extremely close-in (Z = 0.66 ft/lb{sup l/3}) blast loading on the reinforced concrete ff the chamber. Historically, floor damage due to close-in loading has been a common problem for other blast chambers within the US Department of Energy and Department of Defense (DOE/DoD). Blast-effects testing and computer analysis were conducted on a replica quarter-scale model of the preliminary floor design. Nineteen blast tests ranging from scaled distances of 1.14 ft/lb{sup l/3} (25%) to 0.57ft/lb{sup 1/3} (200%) were performed on the strain-gaged floor model. In response to predicted and measured failures at the 25% level, various state-of-the-art blast attenuation systems were quickly developed and tested. The most effective blast-attenuation system provided a significant improvement by reducing the measured floor stresses to acceptable levels while minimizing, by its reusability, the impact on the environment.

  10. Continuum modeling of neuronal cell under blast loading

    PubMed Central

    Jérusalem, Antoine; Dao, Ming

    2012-01-01

    Traumatic brain injuries have recently been put under the spotlight as one of the most important causes of accidental brain dysfunctions. Significant experimental and modeling efforts are thus ongoing to study the associated biological, mechanical and physical mechanisms. In the field of cell mechanics, progresses are also being made at the experimental and modeling levels to better characterize many of the cell functions such as differentiation, growth, migration and death, among others. The work presented here aims at bridging both efforts by proposing a continuum model of neuronal cell submitted to blast loading. In this approach, cytoplasm, nucleus and membrane (plus cortex) are differentiated in a representative cell geometry, and different material constitutive models are adequately chosen for each one. The material parameters are calibrated against published experimental work of cell nanoindentation at multiple rates. The final cell model is ultimately subjected to blast loading within a complete fluid-structure interaction computational framework. The results are compared to the nanoindentation simulation and the specific effects of the blast wave on the pressure and shear levels at the interfaces are identified. As a conclusion, the presented model successfully captures some of the intrinsic intracellular phenomena occurring during its deformation under blast loading and potentially leading to cell damage. It suggests more particularly the localization of damage at the nucleus membrane similarly to what has already been observed at the overall cell membrane. This degree of damage is additionally predicted to be worsened by a longer blast positive phase duration. As a conclusion, the proposed model ultimately provides a new three dimensional computational tool to evaluate intracellular damage during blast loading. PMID:22562014

  11. Failure of underground concrete structures subjected to blast loadings

    NASA Technical Reports Server (NTRS)

    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.

  12. Failure of underground concrete structures subjected to blast loadings

    NASA Technical Reports Server (NTRS)

    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.

  13. 6. OUTER BLAST DOOR, WEST REAR. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. OUTER BLAST DOOR, WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  14. 29 CFR 1926.905 - Loading of explosives or blasting agents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... unattended at the blast site. (h) Machines and all tools not used for loading explosives into bore holes... pneumatically over electric blasting caps, semiconductive delivery hose shall be used and the equipment shall be...

  15. An Analytic Model of Close-Range Blast Fragment Loading

    NASA Astrophysics Data System (ADS)

    Rottenkolber, Ernst; Arnold, Werner

    2006-07-01

    The effects of blast-fragmentation warheads need to be carefully characterized in a variety of applications like passive and active vehicle protection or hard target defeat and TBM defense. With these applications in mind, we have developed a collection of tools called FI-BLAST (Fast Interface for Blast-Fragment Load Analysis of Structures). In the present paper we describe the essential part of these tools, namely the close range blast-fragment model. The meaning of "close range" is here defined as the standoff to a charge at which blast effects can inflict serious damage on massive structures. In order to quantify our model's range of validity, examples of measured and calculated momentum of bare and confined charges are given in the present paper. Short (L/D = 0.5) and long (L/D = 5) cylindrical charges are included as well as spherical charges. The presented examples demonstrate that the model gives reasonable results in the intended domains of application.

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

    PubMed

    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.

  17. Optimum Dynamic Design of Nonlinear Plates under Blast Loading

    DTIC Science & Technology

    1978-03-01

    1978 PLATES UNDER BLAST LOADING 6. PERFORMING ORG . REPORT NUMBER 7. AUTHOR(.) 8. CONTRACT OR GRANT NUMBER(.) J. M. Ferritto 9. PERFORMING ORGANIZATION...coordinate unit vectors q =q1,,2, M Fiur 5 Lgc iara frminimizato of 4- +(X). 4- (ELX + Os’) compute initial I F I ’- F(O) 1:4- F(I)TT-, - 1• I2 1: 1

  18. Explosively driven air blast in a conical shock tube

    SciTech Connect

    Stewart, Joel B. Pecora, Collin

    2015-03-15

    Explosively driven shock tubes present challenges in terms of safety concerns and expensive upkeep of test facilities but provide more realistic approximations to the air blast resulting from free-field detonations than those provided by gas-driven shock tubes. Likewise, the geometry of conical shock tubes can naturally approximate a sector cut from a spherically symmetric blast, leading to a better agreement with the blast profiles of free-field detonations when compared to those provided by shock tubes employing constant cross sections. The work presented in this article documents the design, fabrication, and testing of an explosively driven conical shock tube whose goal was to closely replicate the blast profile seen from a larger, free-field detonation. By constraining the blast through a finite area, large blasts (which can add significant damage and safety constraints) can be simulated using smaller explosive charges. The experimental data presented herein show that a close approximation to the free-field air blast profile due to a 1.5 lb charge of C4 at 76 in. can be achieved by using a 0.032 lb charge in a 76-in.-long conical shock tube (which translates to an amplification factor of nearly 50). Modeling and simulation tools were used extensively in designing this shock tube to minimize expensive fabrication costs.

  19. Explosively driven air blast in a conical shock tube.

    PubMed

    Stewart, Joel B; Pecora, Collin

    2015-03-01

    Explosively driven shock tubes present challenges in terms of safety concerns and expensive upkeep of test facilities but provide more realistic approximations to the air blast resulting from free-field detonations than those provided by gas-driven shock tubes. Likewise, the geometry of conical shock tubes can naturally approximate a sector cut from a spherically symmetric blast, leading to a better agreement with the blast profiles of free-field detonations when compared to those provided by shock tubes employing constant cross sections. The work presented in this article documents the design, fabrication, and testing of an explosively driven conical shock tube whose goal was to closely replicate the blast profile seen from a larger, free-field detonation. By constraining the blast through a finite area, large blasts (which can add significant damage and safety constraints) can be simulated using smaller explosive charges. The experimental data presented herein show that a close approximation to the free-field air blast profile due to a 1.5 lb charge of C4 at 76 in. can be achieved by using a 0.032 lb charge in a 76-in.-long conical shock tube (which translates to an amplification factor of nearly 50). Modeling and simulation tools were used extensively in designing this shock tube to minimize expensive fabrication costs.

  20. Air Blasts from Cased and Uncased Explosives

    SciTech Connect

    Glenn, L. A.

    2016-04-12

    The problem of a spherical blast in air is solved using the STUN code. For bare charges, the calculations are shown to be in excellent agreement with previous published results. It is demonstrated that, for an unconfined (uncased) chemical explosive, both range and time to effect scale inversely as the cube root of the yield and directly as the cube root of the ambient air density. It is shown that the peak overpressure decays to roughly 1/10 of ambient pressure in a scaled range of roughly 10 m/kg1/3 at sea level. At a height of 30 km, where the ambient density is a factor of 64 less, the range to the same decay increases to 40 m/kg1/3 . As a direct result of the scaling a single calculation suffices for all charge sizes and altitudes. Although the close-in results are sensitive to the nature of the explosive source and the equation of state of the air, this sensitivity is shown to virtually disappear at scaled ranges > 0.5 m/kg1/3 . For cased explosives the case thickness introduces an additional scale factor. Moreover, when the blast wave arrives at the inner case radius the case begins to expand. Fracture occurs when a critical value of the resulting hoop strain is reached, causing the case to shatter into fragments. A model is proposed to describe the size distribution of the fragments and their subsequent motion via drag interaction with the explosion products and ambient air. It is shown that a significant fraction of the charge energy is initially transmitted to the case fragments in the form of kinetic energy; for example, a 1 kg spherical charge with a 5 mm thick steel case has almost 29% of the total charge energy as initial kinetic energy of case fragments. This percentage increases with increasing case thickness and decreases with increasing charge size. The peak overpressure at a given range is 70-85% for cased explosives as compared with uncased and the peak impulse per unit area is 90-95%. The peak overpressure and

  1. Dynamic Analysis of Tunnel in Weathered Rock Subjected to Internal Blast Loading

    NASA Astrophysics Data System (ADS)

    Tiwari, Rohit; Chakraborty, Tanusree; Matsagar, Vasant

    2016-11-01

    The present study deals with three-dimensional nonlinear finite element (FE) analyses of a tunnel in rock with reinforced concrete (RC) lining subjected to internal blast loading. The analyses have been performed using the coupled Eulerian-Lagrangian analysis tool available in FE software Abaqus/Explicit. Rock and RC lining are modeled using three-dimensional Lagrangian elements. Beam elements have been used to model reinforcement in RC lining. Three different rock types with different weathering conditions have been used to understand the response of rock when subjected to blast load. The trinitrotoluene (TNT) explosive and surrounding air have been modeled using the Eulerian elements. The Drucker-Prager plasticity model with strain rate-dependent material properties has been used to simulate the stress-strain response of rock. The concrete damaged plasticity model and Johnson-Cook plasticity model have been used for the simulation of stress-strain response of concrete and steel, respectively. The explosive (TNT) has been modeled using Jones-Wilkins-Lee (JWL) equation of state. The analysis results have been studied for stresses, deformation and damage of RC lining and the surrounding rock. It is observed that damage in RC lining results in higher stress in rock. Rocks with low modulus and high weathering conditions show higher attenuation of shock wave. Higher amount of ground shock wave propagation is observed in case of less weathered rock. Ground heave is observed under blast loading for tunnel close to ground surface.

  2. Analysis of MINIE2013 Explosion Air-Blast Data

    SciTech Connect

    Schnurr, Julie M.; Rodgers, Arthur J.; Kim, Keehoon; Ford, Sean R.; Ramirez, Abelardo L.

    2016-10-14

    We report analysis of air-blast overpressure measurements from the MINIE2013 explosive experiments. The MINIE2013 experiment involved a series of nearly 70 near-surface (height-ofburst, HOB, ranging from -1 to +4 m) low-yield (W=2-20 kg TNT equivalent) chemical highexplosives tests that were recorded at local distances (230 m – 28.5 km). Many of the W and HOB combinations were repeated, allowing for quantification of the variability in air-blast features and corresponding yield estimates. We measured canonical signal features (peak overpressure, impulse per unit area, and positive pulse duration) from the air-blast data and compared these to existing air-blast models. Peak overpressure measurements showed good agreement with the models at close ranges but tended to attenuate more rapidly at longer range (~ 1 km), which is likely caused by upward refraction of acoustic waves due to a negative vertical gradient of sound speed. We estimated yields of the MINIE2013 explosions using the Integrated Yield Determination Tool (IYDT). Errors of the estimated yields were on average within 30% of the reported yields, and there were no significant differences in the accuracy of the IYDT predictions grouped by yield. IYDT estimates tend to be lower than ground truth yields, possibly because of reduced overpressure amplitudes by upward refraction. Finally, we report preliminary results on a development of a new parameterized air-blast waveform.

  3. Energy absorption capabilities of composite sandwich panels under blast loads

    NASA Astrophysics Data System (ADS)

    Sankar Ray, Tirtha

    As blast threats on military and civilian structures continue to be a significant concern, there remains a need for improved design strategies to increase blast resistance capabilities. The approach to blast resistance proposed here is focused on dissipating the high levels of pressure induced during a blast through maximizing the potential for energy absorption of composite sandwich panels, which are a competitive structural member type due to the inherent energy absorption capabilities of fiber reinforced polymer (FRP) composites. Furthermore, the middle core in the sandwich panels can be designed as a sacrificial layer allowing for a significant amount of deformation or progressive failure to maximize the potential for energy absorption. The research here is aimed at the optimization of composite sandwich panels for blast mitigation via energy absorption mechanisms. The energy absorption mechanisms considered include absorbed strain energy due to inelastic deformation as well as energy dissipation through progressive failure of the core of the sandwich panels. The methods employed in the research consist of a combination of experimentally-validated finite element analysis (FEA) and the derivation and use of a simplified analytical model. The key components of the scope of work then includes: establishment of quantified energy absorption criteria, validation of the selected FE modeling techniques, development of the simplified analytical model, investigation of influential core architectures and geometric parameters, and investigation of influential material properties. For the parameters that are identified as being most-influential, recommended values for these parameters are suggested in conceptual terms that are conducive to designing composite sandwich panels for various blast threats. Based on reviewing the energy response characteristic of the panel under blast loading, a non-dimensional parameter AET/ ET (absorbed energy, AET, normalized by total energy

  4. Detailed Comparison of Blast Effects in Air and Vacuum

    SciTech Connect

    Tringe, J W; Molitoris, J D; Garza, R G; Andreski, H G; Batteux, J D; Lauderbach, L M; Vincent, E R; Wong, B M

    2007-07-26

    Although blast mitigation is most often achieved with solid shielding, ambient gas pressure can also affect the coupling of shock waves to solid targets. In this work the role of air as an energy transfer medium was examined experimentally by subjecting identical large-area rectangular witness plates to short-range blast effects in air and vacuum ({approx}50 mtorr) at 25 C. The expanding reactant front of 3 kg C4 charges was observed by fast camera to be cylindrically symmetric in both air and vacuum. The horizontal component of the reactant cloud velocity (perpendicular to the witness plates) was constant in both cases, with values of 3.0 and 5.9 km/s for air and vacuum, respectively. As a result of the blast, witness plates were plastically deformed into a shallow dish geometry, with local maxima 30 and 20 mm deep for air and vacuum, respectively. The average plate deflection from the air blast was 11 mm, {approx}10% deeper than the average vacuum plate deflection. Shock pressure estimates were made with a simple impedance-matching model, and indicate peak values in the 30-50 MPa range are consistent with the reactant cloud density and velocity. However, more detailed analysis is necessary to definitely establish the mechanisms by which air couples shock energy to the plates.

  5. 30 CFR 56.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... brought to the blast site, the blast site shall be attended; barricaded and posted with warning signs... permitted within the blast site shall be those activities directly related to the blasting operation and the... designed to facilitate a continuous process, with the blast fired as soon as possible following...

  6. Mechanical response of brain tissue under blast loading.

    PubMed

    Laksari, Kaveh; Sadeghipour, Keyanoush; Darvish, Kurosh

    2014-04-01

    In this study, a framework for understanding the propagation of stress waves in brain tissue under blast loading has been developed. It was shown that tissue nonlinearity and rate dependence are the key parameters in predicting the mechanical behavior under such loadings, as they determine whether traveling waves could become steeper and eventually evolve into shock discontinuities. To investigate this phenomenon, in the present study, brain tissue has been characterized as a quasi-linear viscoelastic (QLV) material and a nonlinear constitutive model has been developed for the tissue that spans from medium loading rates up to blast rates. It was shown that development of shock waves is possible inside the head in response to high rate compressive pressure waves. Finally, it was argued that injury to the nervous tissue at the microstructural level could be partly attributed to the high stress gradients with high rates generated at the shock front and this was proposed as a mechanism of injury in brain tissue. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Micro CT Analysis of Dynamic Damage in Laminates: Impact vs. blast loading

    NASA Astrophysics Data System (ADS)

    Coles, Laurence A.; Roy, Anish; Silberschmidt, Vadim V.

    2017-05-01

    Dynamic loading is often an unavoidable condition in various applications of carbon-fibre-reinforced polymers and can cause various modes of damage. Realisation of dynamic damage in composites can differ significantly from that under quasi-static loading conditions. A comprehensive study of damage in composites caused by a wide variety of impact and blast loading is currently lacking. The work presents a detailed analysis of damage in specimens of a 2×2 twill weave T300 carbon-fibre/epoxy composite subjected to ballistic loading with both steel and ice projectiles (with energies from 95 J to 865 J at 70-90 m/s and 300-500 m/s, respectively) and air blast (with incident pressures of 0.4 MPa, 0.6 MPa and 0.8 MPa and wave speeds between 650 m/s and 950 m/s). The resultant damage was analysed in-depth based on detailed volumetric data obtained with high-resolution X-ray micro computed tomography.

  8. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Blasting in excavation work under compressed air. 1926.913... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and...

  9. [High-pressure air-blast injury of the esophagus].

    PubMed

    Papp, András; Cseke, László; Tamás, Molnár F; Walter, Ottó; Weninger, Csaba; Horváth, Ors Péter

    2002-04-01

    Blast injuries causing pneumatic damage to the oesophagus are very rare. Patients usually present with respiratory distress, subcutaneous and mediastinal emphysema, and may also have pneumothorax. Ruptures need early repair to avoid serious morbidity and potential lethal complications. We report about a successfully treated 47-year-old patient, who has been admitted to our department with compressed air injury of the oesophagus.

  10. 30 CFR 57.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... initiating systems are brought to the blast site, the blast site shall be attended; barricaded and posted... only activities permitted within the blast site shall be those activities directly related to the... be conducted in a manner designed to facilitate a continuous process, with the blast fired as soon...

  11. Design Considerations For Blast Loads In Pressure Vessels.

    SciTech Connect

    Rodriguez, E. A.; Nickell, Robert E.; Pepin, J. E.

    2007-01-01

    Los Alamos National Laboratory (LANL), under the auspices of the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA), conducts confined detonation experiments utilizing large, spherical, steel pressure vessels to contain the reaction products and hazardous materials from high-explosive (HE) events. Structural design and analysis considerations include: (a) Blast loading phase (i.e., impulsive loading); (b) Dynamic structural response; (c) Fragment (i.e., shrapnel) generation and penetration; (d) Ductile and non-ductile fracture; and (e) Design Criteria to ASME Code Sec. VIII, Div. 3, Impulsively Loaded Vessels. These vessels are designed for one-time-use only, efficiently utilizing the significant plastic energy absorption capability of ductile vessel materials. Alternatively, vessels may be designed for multiple-detonation events, in which case the material response is restricted to elastic or near-elastic range. Code of Federal Regulations, Title 10 Part 50 provides requirements for commercial nuclear reactor licensing; specifically dealing with accidental combustible gases in containment structures that might cause extreme loadings. The design philosophy contained herein may be applied to extreme loading events postulated to occur in nuclear reactor and non-nuclear systems or containments.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Quantification of the Design Relationship Between Ground Vehicle Weight and Occupant Safety Under Blast Loading

    DTIC Science & Technology

    2011-04-01

    response of a vehicle- sized box to a mine blast . While this simplifies the vehicle to a rigid body, not allowing for underbody deformation, it evaluates...pulse. The vehicle mass varies with prescribed changes to the material density properties, and the mine blast load is estimated using the CONWEP...Structure Surrogate Modeling The vehicle blast model was simulated 100 times with a Latin-hypercube sampling strategy (McKay et al ., 1979) over the four

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

    NASA Astrophysics Data System (ADS)

    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

  15. Numerical Modelling of Reinforced Concrete Slabs under Blast Loads of Close-in Detonations Using the Lagrangian Approach

    NASA Astrophysics Data System (ADS)

    Shuaib, M.; Daoud, O.

    2015-07-01

    This paper includes an investigation for the deformations, including deflections and damage modes, which occur in reinforced concrete (RC) slabs when subjected to blast loads of explosions. The slab considered for the investigation is a one-way square RC slab with the dimensions of 1000 x 1000 x 40 mm, fixed supported at two opposite sides. It was subjected to close-in detonations of three different charge weights for a constant standoff distance. For the study, the slab was analysed using the numerical method by means of nonlinear finite element analysis. The slab was modelled as 3-D structural continuum using LS-DYNA software. For concrete modelling, two constitutive models were selected, namely the KCC and Winfrith concrete models. Blast loads were applied to the slab through the Lagrangian approach, and the blast command available in the software, namely LOAD_BLAST_ENHANCED, was selected for the application. The deflections and damage modes results obtained were compared to those from a previously published experiment. From the study, both the KCC and Winfrith concrete models effectively and satisfactorily estimated the actual slab maximum deflection. For damage modes, the KCC model appeared to be capable to capture satisfactorily the general damage mode including flexural cracks. However, the model could not capture the local shear mode at the middle of slab (spallation) because the Lagrangian approach does not simulate the interaction between the ambient air and the solid slab.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Tactical Implications of Air Blast Variations from Nuclear Tests

    DTIC Science & Technology

    1976-11-30

    radiation produced effects of interest are prompt effects; 7 the information used in this analysis comes from the primate studies reported by the Armed Forces...Curran, R. W. Young, and W. F. Davis, "The Performance of Primates Following Exposure to Pulsed Whole-Body Gamma-Neutron Radiation," AFRRI SR 73-1... Gibbons , Nonparametric Statistical Inference, McGraw-Hill Book Company, 1971. 7. C. E. Needham, et al., Nuclear Blast Standard (1 KT), Air Force

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

    SciTech Connect

    Jackson, Scott I; Hill, Larry G; Morris, John S

    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.

  19. Reconstruction of improvised explosive device blast loading to personnel in the open

    NASA Astrophysics Data System (ADS)

    Wiri, Suthee; Needham, Charles

    2016-05-01

    Significant advances in reconstructing attacks by improvised explosive devices (IEDs) and other blast events are reported. A high-fidelity three-dimensional computational fluid dynamics tool, called Second-order Hydrodynamic Automatic Mesh Refinement Code, was used for the analysis. Computer-aided design models for subjects or vehicles in the scene accurately represent geometries of objects in the blast field. A wide range of scenario types and blast exposure levels were reconstructed including free field blast, enclosed space of vehicle cabin, IED attack on a vehicle, buried charges, recoilless rifle operation, rocket-propelled grenade attack and missile attack with single subject or multiple subject exposure to pressure levels from ˜ 27.6 kPa (˜ 4 psi) to greater than 690 kPa (>100 psi). To create a full 3D pressure time-resolved reconstruction of a blast event for injury and blast exposure analysis, a combination of intelligence data and Blast Gauge data can be used to reconstruct an actual in-theatre blast event. The methodology to reconstruct an event and the "lessons learned" from multiple reconstructions in open space are presented. The analysis uses records of blast pressure at discrete points, and the output is a spatial and temporal blast load distribution for all personnel involved.

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

    DTIC Science & Technology

    2016-08-01

    ARL-TR-7741 ● AUG 2016 US Army Research Laboratory Blast-Loading Assessment of Multi- Energy Flash Computed Tomography (MEFCT...2016 US Army Research Laboratory Blast-Loading Assessment of Multi- Energy Flash Computed Tomography (MEFCT) Diagnostic Michael B Zellner...Assessment of Multi- Energy Flash Computed Tomography (MEFCT) Diagnostic 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  1. 29 CFR 1926.905 - Loading of explosives or blasting agents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... unattended at the blast site. (h) Machines and all tools not used for loading explosives into bore holes... holes in open work shall be stemmed to the collar or to a point which will confine the charge. (p... are not water-filled, shall be allowed to cool before explosives are loaded. (s) No loaded holes shall...

  2. 29 CFR 1926.905 - Loading of explosives or blasting agents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... unattended at the blast site. (h) Machines and all tools not used for loading explosives into bore holes... holes in open work shall be stemmed to the collar or to a point which will confine the charge. (p... are not water-filled, shall be allowed to cool before explosives are loaded. (s) No loaded holes shall...

  3. 29 CFR 1926.905 - Loading of explosives or blasting agents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... unattended at the blast site. (h) Machines and all tools not used for loading explosives into bore holes... holes in open work shall be stemmed to the collar or to a point which will confine the charge. (p... are not water-filled, shall be allowed to cool before explosives are loaded. (s) No loaded holes shall...

  4. 29 CFR 1926.905 - Loading of explosives or blasting agents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... unattended at the blast site. (h) Machines and all tools not used for loading explosives into bore holes... holes in open work shall be stemmed to the collar or to a point which will confine the charge. (p... are not water-filled, shall be allowed to cool before explosives are loaded. (s) No loaded holes shall...

  5. Air blast type coal slurry fuel injector

    DOEpatents

    Phatak, R.G.

    1984-08-31

    A device to atomize and inject a coal slurry in the combustion chamber of an internal combustion engine is disclosed which eliminates the use of a conventional fuel injection pump/nozzle. The injector involves the use of compressed air to atomize and inject the coal slurry and like fuels. In one embodiment, the breaking and atomization of the fuel is achieved with the help of perforated discs and compressed air. In another embodiment, a cone shaped aspirator is used to achieve the breaking and atomization of the fuel. The compressed air protects critical bearing areas of the injector.

  6. Air blast type coal slurry fuel injector

    DOEpatents

    Phatak, Ramkrishna G.

    1986-01-01

    A device to atomize and inject a coal slurry in the combustion chamber of an internal combustion engine, and which eliminates the use of a conventional fuel injection pump/nozzle. The injector involves the use of compressed air to atomize and inject the coal slurry and like fuels. In one embodiment, the breaking and atomization of the fuel is achieved with the help of perforated discs and compressed air. In another embodiment, a cone shaped aspirator is used to achieve the breaking and atomization of the fuel. The compressed air protects critical bearing areas of the injector.

  7. Novel method to dynamically load cells in 3D-hydrogels culture for blast injury studies

    NASA Astrophysics Data System (ADS)

    Sory, David R.; Areias, Anabela C.; Overby, Darryl R.; Proud, William G.

    2017-01-01

    For at least a century explosive devices have been one of the most important causes of injuries in military conflicts as well as in terrorist attacks. Although significant experimental and modelling efforts have been focussed on blast injuries at the organ or tissue level, few studies have investigated the mechanisms of blast injuries at the cellular level. This paper introduces an in vitro method compatible with living cells to examine the effects of high stress and short-duration pulses relevant to blast loadings and blunt trauma. The experimental phase involves high strain-rate axial compression of cylindrical specimens within an hermetically sealed chamber made of biocompatible polymer. Numerical simulations were performed in order to verify the experimental loading conditions and to characterize the loading path within the sample. A proof of concept is presented so as to establish a new window to address fundamental questions regarding blast injury at the cellular level.

  8. The Air Blast Wave from a Nuclear Explosion

    NASA Astrophysics Data System (ADS)

    Reines, Frederick

    The sudden, large scale release of energy in the explosion of a nuclear bomb in air gives rise, in addition to nuclear emanations such as neutrons and gamma rays, to an extremely hot, rapidly expanding mass of air.** The rapidly expanding air mass has an initial temperature in the vicinity of a few hundred thousand degrees and for this reason it glows in its early stages with an intensity of many suns. It is important that the energy density in this initial "ball of fire" is of the order of 3 × 103 times that found in a detonating piece of TNT and hence that the initial stages of the large scale air motion produced by a nuclear explosion has no counterpart in an ordinary. H. E. explosion. Further, the relatively low temperatures ˜2,000°C associated with the initial stages of an H. E. detonation implies that the thermal radiation which it emits is a relatively insignificant fraction of the total energy involves. This point is made more striking when it is remembered that the thermal energy emitted by a hot object varies directly with the temperature in the Rayleigh Jeans region appropriate to the present discussion. The expansion of the air mass heated by the nuclear reaction produces, in qualitatively the same manner as in an H.E. explosion or the bursting of a high pressure balloon, an intense sharp pressure pulse, a shock wave, in the atmosphere. As the pressure pulse spreads outward it weakens due to the combined effects of divergence and the thermodynamically irreversible nature of the shock wave. The air comprising such a pressure pulse or blast wave moves first radially outward and then back towards the center as the blast wave passes. Since a permanent outward displacement of an infinite mass of air would require unlimited energy, the net outward displacement of the air distant from an explosion must approach zero with increasing distance. As the distance from the explosion is diminished the net outward displacement due to irreversible shock heating of

  9. Blast Loading Experiments of Surrogate Models for Tbi Scenarios

    NASA Astrophysics Data System (ADS)

    Alley, M. D.; Son, S. F.

    2009-12-01

    This study aims to characterize the interaction of explosive blast waves through simulated anatomical models. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical PMMA shells housing synthetic gelatins as brain simulants have been utilized. A series of experiments was conducted to compare the sensitivity of the system response to mechanical properties of the simulants under high strain-rate explosive blasts. Small explosive charges were directed at the models to produce a realistic blast wave in a scaled laboratory test cell setting. Blast profiles were measured and analyzed to compare system response severity. High-speed shadowgraph imaging captured blast wave interaction with the head model while particle tracking captured internal response for displacement and strain correlation. The results suggest amplification of shock waves inside the head near material interfaces due to impedance mismatches. In addition, significant relative displacement was observed between the interacting materials suggesting large strain values of nearly 5%. Further quantitative results were obtained through shadowgraph imaging of the blasts confirming a separation of time scales between blast interaction and bulk movement. These results lead to the conclusion that primary blast effects could cause TBI occurrences.

  10. Antioxidant loading reduces oxidative stress induced by high-energy impulse noise (blast) exposure.

    PubMed

    Elsayed, N M; Armstrong, K L; William, M T; Cooper, M F

    2000-11-30

    Detonation of explosives, firing of large caliber weapons and occupational explosions, professional or accidental, produce high-energy impulse noise (blast) waves characterized by a rapid rise in atmospheric pressure (overpressure) followed by gradual decay to ambient level. Exposure to blast waves causes injury, predominantly to the hollow organs such as ears and lungs. We have previously reported that blast exposure can induce free radical-mediated oxidative stress in the lung characterized by antioxidant depletion, lipid peroxidation, and hemoglobin (Hb) oxidation. In this study, we examined whether pre-loading, adequately fed rats, with pharmacological doses of antioxidants would reduce the response to blast. Sprague-Dawley rats weighing 300-350 g were loaded with either 800 IU vitamin E (VE), 1000 mg vitamin C (VC) or 25 mg lipoic acid (LA) for 3 consecutive days by gavage before exposure to blast. Both VE, and LA were dissolved in 2 ml corn oil, but VC in 2 ml water. After the 3-day antioxidant loading, the rats were divided into six groups (five rats per group), deeply anesthetized with sodium pentobarbital (60 mg/kg body weight), then exposed to a low-level blast (62+/-2 kPa peak pressure and 5 ms duration). A matched number of groups were sham exposed and served as controls. One hour after exposure, all rats were euthanized then blood, and lung tissue was analyzed. We found that antioxidant loading resulted in restored Hb oxygenation, and reduced lipid peroxidation. Lung tissue VE content was elevated after loading but VC did not change possibly due to their different bioavailability and saturation kinetics. These observations, suggest that brief antioxidant loading with pharmacological doses can reduce blast-induced oxidative stress, and may have occupational and clinical implications.

  11. 30 CFR 57.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... connecting to the power source, and in nonelectric blasting prior to attaching an initiating device, all... them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1)...

  12. 30 CFR 56.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... notify the appropriate MSHA district office. (e) In electric blasting prior to connecting to the power... (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given...

  13. 30 CFR 57.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... connecting to the power source, and in nonelectric blasting prior to attaching an initiating device, all... them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1)...

  14. 30 CFR 56.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... notify the appropriate MSHA district office. (e) In electric blasting prior to connecting to the power... (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given...

  15. 30 CFR 56.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... notify the appropriate MSHA district office. (e) In electric blasting prior to connecting to the power... (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given...

  16. 30 CFR 57.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... connecting to the power source, and in nonelectric blasting prior to attaching an initiating device, all... them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1)...

  17. 30 CFR 56.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... notify the appropriate MSHA district office. (e) In electric blasting prior to connecting to the power... (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given to...

  18. 30 CFR 57.6306 - Loading, blasting, and security.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... connecting to the power source, and in nonelectric blasting prior to attaching an initiating device, all... them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample...

  19. Blast Loading Experiments of Developed Surrogate Models for TBI Scenarios

    NASA Astrophysics Data System (ADS)

    Alley, Matthew; Son, Steven

    2009-06-01

    This study aims to characterize the interaction of explosive blast waves through simulated anatomical systems. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical PMMA shells followed by SLA prototyped skulls housing synthetic gelatins as brain simulants have been utilized. A series of experiments was conducted with the simple geometries to compare the sensitivity of the system response to mechanical properties of the simulants under high strain-rate explosive blasts. Small explosive charges were directed at the models to produce a realistic blast wave in a scaled laboratory setting. Blast profiles were measured and analyzed to compare system response severity. High-speed shadowgraph imaging captured blast wave interaction with the head model while particle tracking captured internal response for displacement and strain correlation. The results suggest amplification of shock waves inside the head due to impedance mismatches. Results from the strain correlations added to the theory of internal shearing between tissues.

  20. Antisymmetric and Symmetric Functionally Graded Plate-Type Structures Impacted by Blast Loading

    DTIC Science & Technology

    2010-09-13

    IMPACTED BY BLAST LOADING Terry Hause, Ph.D. Research Mechanical Engineer U.S. Army RDECOM-TARDEC Warren, MI 48397 Sudhakar, Arepally Deputy...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Terry Hause, Ph.D.; Sudhakar, Arepally 5d. PROJECT NUMBER 5e. TASK NUMBER

  1. Comparison of Hybrid-III and postmortem human surrogate response to simulated underbody blast loading.

    PubMed

    Bailey, Ann Marie; Christopher, John J; Salzar, Robert S; Brozoski, Frederick

    2015-05-01

    Response of the human body to high-rate vertical loading, such as military vehicle underbody blast (UBB), is not well understood because of the chaotic nature of such events. The purpose of this research was to compare the response of postmortem human surrogates (PMHS) and the Hybrid-III anthropomorphic test device (ATD) to simulated UBB loading ranging from 100 to 860 g seat and floor acceleration. Data from 13 whole body PMHS tests were used to create response corridors for vertical loading conditions for the pelvis, T1, head, femur, and tibia; these responses were compared to Hybrid-III responses under matched loading conditions.

  2. Head Kinematics Resulting from Simulated Blast Loading Scenarios

    DTIC Science & Technology

    2012-09-17

    LS - Dyna sulting from he coordinate pressure, ref shockwave stories for a triple point h the Mach fro waves respec converge int sus time of ta...capabilities implemented in LS - Dyna . This method models most major characteristics of a blast wave including overpressures and Mach stem effects by applying a...Waterways Experiment Station, Corps of Engineers; 1998. [21] Livermore Software Technology Corporation (LSTC). (2010). Ls - dyna keyword user’s manual. 1(Version 971/Rev 5)

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    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.

  5. Composite Vessels for Containment of Extreme Blast Loadings

    SciTech Connect

    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.

  6. Evaluation of Five Additional Enhancements to the Building Loads Analysis and System Thermodynamics (BLAST) Program

    DTIC Science & Technology

    1993-04-01

    FINDINGS AND RECOMMENDATIONS OF TEST/DEMONSTRATION U’ WORK UNIT NO./TITLE OF TEST: T3B, Blast Enhancements Evaluation PERFORMING LABORATORY: USACERL...gram, work unit EA-KAI, "Test New BLAST Enhancements," and project 4A162784AT45, "Energy and Energy Conservation," work unit XG2, "Energy Analysis...air economy cycle. 2. SZDT-DX. Single zone draw-through fan systems with a direct expansion condensing unit tor zones 1, 2, and 3. Zone I

  7. Evaluation of overpressure prediction models for air blast above the triple point.

    PubMed

    Ehrhardt, L; Boutillier, J; Magnan, P; Deck, C; De Mezzo, S; Willinger, R; Cheinet, S

    2016-07-05

    The increase of blast exposures leads to the need for better assessment of the blast threat. Empirical models describing the blast propagation in ideal conditions as free-field or surface detonations are commonly employed, but in some configurations the ground-reflected shock should be treated explicitly. Empirical models permit the prediction of the blast characteristics with the ground-reflected shock. The present study uses some original experimental data to evaluate the accuracy of the predicted overpressure with time regarding the reflected shock characteristics. Three methods are tested. The first method, called method of images (MOI) and linearly adding a virtual ground-symmetrical source blast to the free-field blast, is quick but lacks accuracy regarding the reflected shock characteristics. The second method, based on the LOAD_BLAST_ENHANCED function of the commercial LS-DYNA framework, better captures the reflected shock compared to the MOI, but the overall differences with experimental data are of the same order of magnitude as for the MOI. An original fit is introduced, based on standard physical parameters. The accuracy of this fit on the reflected shock characteristics, and the better match with the overall overpressure time series, shows its potential as a new empirical blast predicting tool. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Building Loads Analysis and System Thermodynamics (BLAST) program users manual. Volume 1: Supplement (version 3.0)

    NASA Astrophysics Data System (ADS)

    Herron, D.; Walton, G.; Lawrie, L.

    1981-03-01

    BLAST Version 3.0 can be used to model passive solar applications and to analyze large-scale industrial facilities. Parameters, users can study with BLAST Version 3.0 (in addition to BLAST 2.0 capabilities) include (1) interzone heat transfer and ventilation, (2) movable insulation, (3) daylighting, (4) exact internal solar distribution, (5) radiant temperature control, (6) exterior radiant interchange, (7) mechanical ventilation, (8) process heat as heat source, (9) latent air-to-air heat recovery, (10) water-cooled packaged systems, (11) induction unit systems, (12) direct-drive chillers, and (13) purchased steam from utilities. BLAST version 3.0 also offers the user a generalized report writer and several new output report options not available from BLAST Version 2.0. Although the simulation capabilities of BLAST Version 3.0 are expanded over BLAST Version 2.0, users familiar with BLAST Version 2.0 can use Version 3.0 without modifying their approach or their BLAST input.

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

    DTIC Science & Technology

    2010-05-11

    apeak) Livermore Software Technology Corporation (2007). LS - DYNA Keyword User’s Manual. http://lstc.com/pdf/ ls -dyna_971_manual_k.pdf, accessed April...B Ground Vehicle Weight and Occupant Safety Under Blast Loading Steven Hoffenson, presenter (U of M) Panos Papalambros, PI (U of M) Michael...Safety Considerations, Part B Ground Vehicle Weight and Occupant Safety Under Blast Loading 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  10. Droplet Breakup Mechanisms in Air-blast Atomizers

    NASA Astrophysics Data System (ADS)

    Aliabadi, Amir Abbas; Taghavi, Seyed Mohammad; Lim, Kelly

    2011-11-01

    Atomization processes are encountered in many natural and man-made phenomena. Examples are pollen release by plants, human cough or sneeze, engine fuel injectors, spray paint and many more. The physics governing the atomization of liquids is important in understanding and utilizing atomization processes in both natural and industrial processes. We have observed the governing physics of droplet breakup in an air-blast water atomizer using a high magnification, high speed, and high resolution LASER imaging technique. The droplet breakup mechanisms are investigated in three major categories. First, the liquid drops are flattened to form an oblate ellipsoid (lenticular deformation). Subsequent deformation depends on the magnitude of the internal forces relative to external forces. The ellipsoid is converted into a torus that becomes stretched and disintegrates into smaller drops. Second, the drops become elongated to form a long cylindrical thread or ligament that break up into smaller drops (Cigar-shaped deformation). Third, local deformation on the drop surface creates bulges and protuberances that eventually detach themselves from the parent drop to form smaller drops.

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

    PubMed

    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.

  12. A History of Air-Blast Sprayer Development and Future Prospects

    USDA-ARS?s Scientific Manuscript database

    The design and operating procedures of air-blast sprayers have been greatly improved over the past 50 years. Early tree and vine s pray application equipment used hand-guns that required large amount of water. Later, sprayers with efficient fans, producing large volumes of air at high velocities, ...

  13. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2013-10-01

    Conclusion 8 ii 1 Introduction In the life of a combat soldier, traumatic cataract in ocular lenses may result from blast load- ing, whereby (i) the...the passing shock wave. Traumatic cataract can result in a partially or fully clouded lens, complete dislo- cation of the lens (floating between...aqueous and vitreous humors, see Fig.1), or zonule rupture such that partial or full vision loss may occur. The mechanisms of traumatic cataract forma

  14. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2014-10-01

    soldier, traumatic cataract in ocular lenses may result from blast load- ing, whereby (i) the lens capsule (Fig.1) is perforated by intraocular foreign...1), and/or (iii) the lens internal substance (crystallins lens fiber cells) is stressed by the passing shock wave. Traumatic cataract can result in a...that partial or full vision loss may occur. The mechanisms of traumatic cataract forma- tion that may require cataract surgery (implantation of an

  15. Parameters Affecting Loads on Buried Structures Subjected to Localized Blast Effects

    DTIC Science & Technology

    1992-04-01

    Structures Laboratory DEPARTMENT OF THE ARMY Waterways Experiment Station, Corps of Engineers 3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199...ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER US Army Engineer Waterways Experiment Station, Structures Laboratory, Technical Report SL-92-9...Loads on Buried Structures Subjected to Localized Blast Effects." These analyses were performed in the Structures Laboratory (SL), U.S. Army Engineer

  16. Damage Assessment of Two-Way Bending RC Slabs Subjected to Blast Loadings

    PubMed Central

    Jia, Haokai; Wu, Guiying

    2014-01-01

    Terrorist attacks on vulnerable structures and their individual structural members may cause considerable damage and loss of life. However, the research work on response and damage analysis of single structural components, for example, a slab to blast loadings, is limited in the literature and this is necessary for assessing its vulnerability. This study investigates the blast response and damage assessment of a two-way bending reinforced concrete (RC) slab subjected to blast loadings. Numerical modeling and analysis are carried out using the commercial finite element code LS-DYNA 971. A damage assessment criterion for the two-way bending RC slab is defined based on the original and residual uniformly distributed load-carrying capacity. Parametric studies are carried out to investigate the effects of explosive weight and explosive position on the damage mode of the two-way RC slab. Some design parameters, such as the boundary conditions and the negative reinforcement steel bar length, are also discussed. The illustrated results show that the proposed criterion can apply to all failure modes. The damage assessment results are more accurate than the ones due to the conventional deformation criterion. PMID:25121134

  17. Damage assessment of two-way bending RC slabs subjected to blast loadings.

    PubMed

    Jia, Haokai; Yu, Ling; Wu, Guiying

    2014-01-01

    Terrorist attacks on vulnerable structures and their individual structural members may cause considerable damage and loss of life. However, the research work on response and damage analysis of single structural components, for example, a slab to blast loadings, is limited in the literature and this is necessary for assessing its vulnerability. This study investigates the blast response and damage assessment of a two-way bending reinforced concrete (RC) slab subjected to blast loadings. Numerical modeling and analysis are carried out using the commercial finite element code LS-DYNA 971. A damage assessment criterion for the two-way bending RC slab is defined based on the original and residual uniformly distributed load-carrying capacity. Parametric studies are carried out to investigate the effects of explosive weight and explosive position on the damage mode of the two-way RC slab. Some design parameters, such as the boundary conditions and the negative reinforcement steel bar length, are also discussed. The illustrated results show that the proposed criterion can apply to all failure modes. The damage assessment results are more accurate than the ones due to the conventional deformation criterion.

  18. Prediction of blast-induced air overpressure: a hybrid AI-based predictive model.

    PubMed

    Jahed Armaghani, Danial; Hajihassani, Mohsen; Marto, Aminaton; Shirani Faradonbeh, Roohollah; Mohamad, Edy Tonnizam

    2015-11-01

    Blast operations in the vicinity of residential areas usually produce significant environmental problems which may cause severe damage to the nearby areas. Blast-induced air overpressure (AOp) is one of the most important environmental impacts of blast operations which needs to be predicted to minimize the potential risk of damage. This paper presents an artificial neural network (ANN) optimized by the imperialist competitive algorithm (ICA) for the prediction of AOp induced by quarry blasting. For this purpose, 95 blasting operations were precisely monitored in a granite quarry site in Malaysia and AOp values were recorded in each operation. Furthermore, the most influential parameters on AOp, including the maximum charge per delay and the distance between the blast-face and monitoring point, were measured and used to train the ICA-ANN model. Based on the generalized predictor equation and considering the measured data from the granite quarry site, a new empirical equation was developed to predict AOp. For comparison purposes, conventional ANN models were developed and compared with the ICA-ANN results. The results demonstrated that the proposed ICA-ANN model is able to predict blast-induced AOp more accurately than other presented techniques.

  19. 78. PIPING CHANNEL FOR FUEL LOADING, FUEL TOPPING, COMPRESSED AIR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    78. PIPING CHANNEL FOR FUEL LOADING, FUEL TOPPING, COMPRESSED AIR, GASEOUS NITROGEN, AND HELIUM - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  20. An Empirical Model for Mine-Blast Loading

    DTIC Science & Technology

    2014-10-17

    types and under various conditions and to develop enhanced numerical models for the loading generated by these threats [16]. The frame setup shown in...control over the target sizes, boundary conditions of the target and better monitoring of the target back face for observing the local deformation and... give the right solution. The goal of this work is to narrow down these possibilities and determine a ’’working’’ loading that can be used for design

  1. An efficient approach to model response of submerged structures to blast loading

    SciTech Connect

    Manfredini, G.M.; Lagasco, F.; Drake, J.L.

    1996-12-31

    Blast loading on submerged offshore structures due to fishing activities and hostile attacks is a concern to Oil Operators. The dynamic response of structures interacting with the fluid has been extensively detailed in the past. An efficient state-of-the-art methodology is presented to evaluate the structural behavior of underwater nearby blasts to steel and concrete elastoplastic structures. Contact charges require analyses by means of hydrocodes and are not covered in this contribution. The water shock model and the structure-medium interaction model are treated in detail, while a general description is given for the two dimensional lumped mass incremental implicit beam element code. Due to its nature the code is particularly suited to analyze the response of one dimensional extended structures, but appropriate results have been found also in cases where three-dimensional effects are predominant. Results of the blast code include time histories of structural ductility, which can be interpreted as a damage indicator in the consequence analyses. The performance of the blast methodology is evaluated by comparing numerical results with an experimental test of underwater explosion against a stiffened plate.

  2. Air blast injuries killed the crew of the submarine H.L. Hunley

    PubMed Central

    Stalcup, Lucas; Wojtylak, Brad; Bass, Cameron R.

    2017-01-01

    The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb) black powder torpedo at a distance less than 5 m (16 ft) off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull. PMID:28832592

  3. Intrathoracic pressure variations in an anthropomorphic dummy exposed to air blast, blunt impact, and missiles.

    PubMed

    Jönsson, A; Arvebo, E; Schantz, B

    1988-01-01

    Experiments with an anthropomorphic dummy for blast research demonstrated that pressures recorded in the lung model of the dummy could be correlated to primary air blast effects on the lungs of experimental animals. The results presented here were obtained with a dummy of the type mentioned above, but with the lung model modified to improve geometric similarity to man. Blast experiments were performed in a shock tube, and impact experiments in a special impact machine. Experiments with nonpenetrating missiles were performed with small-caliber firearms and the dummy protected by body armor. Severity indices derived from the blast experiments were related to established criteria for primary lung injury in man. Impacts delivered in the impact machine and by nonpenetrating missiles are compared. Relationships between severity of impact based on experiments with animals and primary lung injury in man are discussed.

  4. Analysis of concrete targets with different kinds of reinforcements subjected to blast loading

    NASA Astrophysics Data System (ADS)

    Oña, M.; Morales-Alonso, G.; Gálvez, F.; Sánchez-Gálvez, V.; Cendón, D.

    2016-05-01

    In this paper we describe an experimental campaign carried out to study and analyse the behaviour of concrete slabs when subjected to blast loading. Four different types of concrete have been tested: normal strength concrete with steel rebar, normal strength concrete with steel rebar retrofitted with Kevlar coating, steel fibre reinforced concrete (SFRC) and polypropylene fibre reinforced concrete (PFRC). The major asset of the experimental setup used is that it allows to subject up to four specimens to the same blast load what, besides being cost effective, makes possible to have a measure of the experimental scatter. The results of SFRC and PFRC concretes have been analysed by using a previously developed material model for the numerical simulation of concrete elements subjected to blast. The experimental campaign and preliminary results of this numerical analysis show how the high strain rates, in spite of improving the mechanical properties of these kinds of fibre reinforced concretes, lead to an embrittlement of the material, which may be dangerous from the point of view of the structural behaviour.

  5. Numerical Investigations on a Blast Loaded Laced Reinforced Concrete Structure using an Equivalent Constitutive Property

    NASA Astrophysics Data System (ADS)

    Anandavalli, N.; Lakshmanan, N.; Prakash, Amar; Rajasankar, J.; Iyer, Nagesh R.

    2015-12-01

    A Laced Reinforced Concrete (LRC) structural element consists of continuously inclined shear reinforcement in the form of lacing that tie the longitudinal reinforcements on both faces of the structural element. LRC is used particularly in blast resistant construction. Conventional finite element modeling of reinforced concrete (RC) structures requires concrete and steel to be considered as separate entities and interaction between them to be defined through smeared, discrete or embedded approach. In this paper, a new approach for modeling RC structures is adopted to analyse a blast loaded LRC structure. Present approach considers RC/LRC as a homogenous material, whose constitutive property is derived based on the moment-curvature relationship of the structural component. An equivalent single-degree-of-freedom system obtained based on a proven technique is analysed to verify the results of the finite element analysis. Present approach significantly reduces the modeling effort and in turn, the computational demand for a given accuracy in the results.

  6. Analysis of Functionally Graded Shells Subjected to Blast Loads

    DTIC Science & Technology

    2008-07-21

    and the bending stiffness matrices, respectively. For an FGM , E = E (x3), v = v (x3) and α = α (x3), where E, v and α are, respectively, Young’s...temperatures, new structural paradigms, enabling one to overcome these adverse effects, are needed. Advances in functionally graded materials ( FGMs ) [1...curved shells made of FGMs to time-dependent loads induced by an explo- sion, a sonic-boom or a shock wave is studied. 2 Phase distribution and

  7. Development of a 3D numerical methodology for fast prediction of gun blast induced loading

    NASA Astrophysics Data System (ADS)

    Costa, E.; Lagasco, F.

    2014-05-01

    In this paper, the development of a methodology based on semi-empirical models from the literature to carry out 3D prediction of pressure loading on surfaces adjacent to a weapon system during firing is presented. This loading is consequent to the impact of the blast wave generated by the projectile exiting the muzzle bore. When exceeding a pressure threshold level, loading is potentially capable to induce unwanted damage to nearby hard structures as well as frangible panels or electronic equipment. The implemented model shows the ability to quickly predict the distribution of the blast wave parameters over three-dimensional complex geometry surfaces when the weapon design and emplacement data as well as propellant and projectile characteristics are available. Considering these capabilities, the use of the proposed methodology is envisaged as desirable in the preliminary design phase of the combat system to predict adverse effects and then enable to identify the most appropriate countermeasures. By providing a preliminary but sensitive estimate of the operative environmental loading, this numerical means represents a good alternative to more powerful, but time consuming advanced computational fluid dynamics tools, which use can, thus, be limited to the final phase of the design.

  8. Experimental determination of blast-wave pressure loading, thermal radiation protection, and electrical transmission loss for parabolic antenna models in simulated nuclear blast environments

    SciTech Connect

    George, J.H.

    1991-01-01

    A twelve-inch-diameter parabolic antenna model instrumented with eleven differential pressure sensors was tested at the Ballistics Research Laboratory, Aberdeen Proving Ground, Maryland. Transient pressure loading was determined for 37 different antenna model angular positions with respect to the direction of the blast wave at a peak overpressure of 3.0 pounds per square inch; limited data at 4.5 and 6.0 pounds per square inch were also investigated. The first millisecond of shock-wave interaction with the antenna features the most prominent fully reversed triangular pressure pulse. A blast function, F, was developed that accurately approximates the transient behavior of the blast wave resultant force and moment loading on the antenna model. The resultant blast force on the antenna model is minimized when the axis of the paraboloid of the model is rotated 82{degree} with respect to the direction of the blast wave. Four different thermal protective coatings were tested to evaluate the effects of coating color and thickness. Transmission-loss measurements were completed on eight different quartz-polyimide antenna models coated with Caapcoat and Ocean 477 thermal protective coatings.

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

    NASA Astrophysics Data System (ADS)

    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. 500-kV HVDC air-blast circuit breaker. Final report

    SciTech Connect

    Bachman, B.; Ruoss, E.

    1986-08-01

    This report describes the first HVDC circuit breaker to be tested on a full-scale utility system. Modular in construction to ensure economic feasibility, this breaker has a standard ac air-blast breaker as its main component and interrupts current up to 2200-A dc.

  11. Finite element analysis of the Arquin-designed CMU wall under a dynamic (blast) load.

    SciTech Connect

    Lopez, Carlos; Petti, Jason P.

    2008-12-01

    The Arquin Corporation designed a CMU (concrete masonry unit) wall construction and reinforcement technique that includes steel wire and polymer spacers that is intended to facilitate a faster and stronger wall construction. Since the construction method for an Arquin-designed wall is different from current wall construction practices, finite element computer analyses were performed to estimate the ability of the wall to withstand a hypothetical dynamic load, similar to that of a blast from a nearby explosion. The response of the Arquin wall was compared to the response of an idealized standard masonry wall exposed to the same dynamic load. Results from the simulations show that the Arquin wall deformed less than the idealized standard wall under such loading conditions. As part of a different effort, Sandia National Laboratories also looked at the relative static response of the Arquin wall, results that are summarized in a separate SAND Report.

  12. Experimental study on crack coalescence mechanisms of pre-existing flaws under blast loading

    NASA Astrophysics Data System (ADS)

    Yue, Zhong-wen; Yang, Ren-shu; Ma, Xin-min; Guo, Dong-ming

    2008-11-01

    The PMMA model transmission-type experiment of dynamic caustics was carried out to simulate the fracture blasting process of material containing pre-existing flaws using the dynamic caustic-test system. The mechanism of the fracture coalescence among four prefabricated flaws with echelon geometry distribution was studied under blast loading. The experiment results show that two wing cracks respectively coalescing with the flaw F2 and flaw F3 appear at both tips of the flaw F1 closest to the blasthole. Whereas the flaw F4 doesn't produce wing cracks, the flaw F2 and flaw F3 also respectively generate two wing cracks which don't link up the flaw F4. Crack propagation is greatly affected by preexisting flaws. During the whole fracture process, the wing crack velocity oscillates with the increase of crack propagating time. The value of dynamic stress intensity factor reaches the maximum in a moment and then gradually decreases. The changes of dynamic stress intensity factor also oscillate in the whole time. Furthermore, the value of dynamic stress intensity factor KdII is smaller than that of dynamic stress intensity factor KdI. The results of the present research can provide the theoretical basis for the study on blasting of rock containing flaws.

  13. An open air research study of blast-induced traumatic brain injury to goats.

    PubMed

    Chen, Hui-Jun; Xu, Chuan; Li, Yue; Chen, Zhi-Qiang; Li, Guan-Hua; Duan, Zhao-Xia; Li, Xiao-Xia; Zhang, Jie-Yuan; Wang, Zhe; Feng, Hua; Li, Bing-Cang

    2015-01-01

    We once reported blast-induced traumatic brain injury (bTBI) in confined space. Here, bTBI was studied again on goats in the open air using 3.0 kg trinitrotoluene. The goats were placed at 2, 4, 6 and 8 m far from explosion center. Trinitrotoluene (TNT) was used as the source of the blast wave and the pressure at each distance was recorded. The systemic physiology, electroencephalogram, serum level of S-100 beta, and neuron specific enolase (NSE) were determined pre and post the exposure. Neuroanatomy and neuropathology were observed 4 h after the exposure. Simple blast waveforms were recorded with parameters of 702.8 kPa-0.442 ms, 148.4 kPa-2.503 ms, 73.9 kPa-3.233 ms, and 41.9 kPa-5.898 ms at 2, 4, 6 and 8 m respectively. Encephalic blast overpressure was on the first time recorded in the literature by us at 104.2 kPa-0.60 ms at 2 m, where mortality and burn rate were 44% and 44%. Gross examination showed that bTBI was mainly manifested as congestive expansion of blood vessels and subarachnoid hemorrhage, which had a total incidence of 25% and 19% in 36 goats. Microscopical observation found that the main pathohistological changes were enlarged perivascular space (21/36, 58%), small hemorrhages (9/36, 25%), vascular dilatation and congestion (8/36, 22%), and less subarachnoid hemorrhage (2/36, 6%). After explosion, serum levels of S-100b and NSE were elevated, and EEG changed into slow frequency with declined amplitude. The results indicated that severity and incidence of bTBI is related to the intensity of blast overpressure. Blast wave can pass through the skull to directly injure brain tissue.

  14. Numerical simulations of the occupant head response in an infantry vehicle under blunt impact and blast loading conditions.

    PubMed

    Sevagan, Gopinath; Zhu, Feng; Jiang, Binhui; Yang, King H

    2013-07-01

    This article presents the results of a finite element simulation on the occupant head response in an infantry vehicle under two separated loading conditions: (1) blunt impact and (2) blast loading conditions. A Hybrid-III dummy body integrated with a previously validated human head model was used as the surrogate. The biomechanical response of the head was studied in terms of head acceleration due to the impact by a projectile on the vehicle and intracranial pressure caused by blast wave. A series of parametric studies were conducted on the numerical model to analyze the effect of some key parameters, such as seat configuration, impact velocity, and boundary conditions. The simulation results indicate that a properly designed seat and internal surface of the infantry vehicle can play a vital role in reducing the risk of head injury in the current scenarios. Comparison of the kinematic responses under the blunt impact and blast loading conditions reveals that under the current loading conditions, the acceleration pulse in the blast scenario has much higher peak values and frequency than blunt impact case, which may reflect different head response characteristics.

  15. Novel method to dynamically load cells in 3D-gel culture for primary blast injury studies

    NASA Astrophysics Data System (ADS)

    Sory, David; Cepa-Areias, Anabela; Overby, Darryl; Proud, William; Institute of Shock Physics, Department of Bioengineering; Royal British Legion CentreBlast I Collaboration

    2015-06-01

    For at least a century explosive devices have been reported as one of the most important causes of injuries on battlefield in military conflicts as well as in terrorist attacks. Although significant experimental and modelling efforts have been focussed on blast injury at the organ or tissue level, few studies have investigated the mechanism of blast injury at the cellular level. This paper introduces an in vitro method compatible with living cells to examine the effects of high stress and short-duration pulses similar to those observed in blast waves. The experimental phase involved high strain rate axial compression of biological cylindrical specimens within a hermetically sealed sample holder made of a biocompatible polymer. Numerical simulations were performed in order to characterize the loading path within the sample and assess the loading conditions. A proof of concept is presented so as to establish a new window to address fundamental questions regarding primary blast injury at the cellular level. 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.

  16. Aviary air-handler design and its relationship to fungal spore loads in the air.

    PubMed

    Dykstra, Michael J; Reininger, Kenneth

    2007-12-01

    Fungal spore loads in the air of cool-temperature, temperate, and tropical aviaries were collected with an Andersen N-6 air sampler. The relationship of spore loads to air-handler and exhibit design in these three environments was examined. In addition, a 2-yr longitudinal study of fungal spore loads in the air of a newly designed and installed air-handling system in the R. J. Reynolds Forest Aviary at the North Carolina Zoological Park was compared to the earlier air-handling system that it replaced. High-efficiency particulate air filters installed in cool-temperature aviaries produced the cleanest air, although pleated filters showed only marginally higher spore loads. Temperate and tropical aviaries with pleated filters or bag filters with variable-velocity fans had much higher spore loads. Tropical and temperate exhibits with bag filters and constant-velocity fans produced the cleanest air in tropical and temperate exhibits. Information on the relative effectiveness of different air-handling system designs and related costs/benefits should be used by zoo managers when they are designing or retrofitting aviary air-handling systems.

  17. A geophysical shock and air blast simulator at the National Ignition Facility

    SciTech Connect

    Fournier, K. B.; Brown, C. G.; May, M. J.; Compton, S.; Walton, O. R.; Shingleton, N.; Kane, J. O.; Holtmeier, G.; Loey, H.; Mirkarimi, P. B.; Dunlop, W. H.; Guyton, R. L.; Huffman, E.

    2014-09-01

    The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismic and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.

  18. A geophysical shock and air blast simulator at the National Ignition Facility.

    PubMed

    Fournier, K B; Brown, C G; May, M J; Compton, S; Walton, O R; Shingleton, N; Kane, J O; Holtmeier, G; Loey, H; Mirkarimi, P B; Dunlop, W H; Guyton, R L; Huffman, E

    2014-09-01

    The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismic and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.

  19. A geophysical shock and air blast simulator at the National Ignition Facility

    SciTech Connect

    Fournier, K. B.; Brown, C. G.; May, M. J.; Compton, S.; Walton, O. R.; Shingleton, N.; Kane, J. O.; Holtmeier, G.; Loey, H.; Mirkarimi, P. B.; Dunlop, W. H.; Guyton, R. L.; Huffman, E.

    2014-09-15

    The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismic and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.

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

    SciTech Connect

    Taylor, Paul A.; Cooper, Candice Frances; Burnett, Damon J.

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

    PubMed

    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.

  2. Response of laminated composite flat panels to sonic boom and explosive blast loadings

    NASA Technical Reports Server (NTRS)

    Librescu, L.; Nosier, A.

    1990-01-01

    This paper deals with a theoretical analysis of the dynamic response of shear deformable symmetrically laminated rectangular composite flat panels exposed to sonic boom and explosive blast loadings. The pertinent governing equations incorporating transverse shear deformation, transverse normal stress, as well as the higher-order effects are solved by using the integral-transform technique. The obtained results are compared with their counterparts obtained within the framework of the first-order transverse shear deformation and the classical plate theories and some conclusions concerning their range of applicability are outlined. The paper also contains a detailed analysis of the influence played by the various parameters characterizing the considered pressure pulses as well as the material and geometry of the plate.

  3. Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park

    USGS Publications Warehouse

    Morrissey, M.M.; Savage, W.Z.; Wieczorek, G.F.

    1999-01-01

    The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior of the second air blast that downed over 1000 trees, destroyed a bridge, demolished a snack bar, and caused one fatality and several injuries. Calculated velocities for the air blast from a two-phase, finite difference model are compared to velocities estimated from tree damage. From tornadic studies of tree damage, the air blast is estimated to have traveled <108-120 m/s within 50 m from the impact and decreased to <10-20 m/s within 500 m from the impact. The numerical model simulates the two-dimensional propagation of an air blast through a dusty atmosphere with initial conditions defined by the impact velocity and pressure. The impact velocity (105-107 m/s) is estimated from the Colorado Rockfall Simulation Program that simulates rockfall trajectories. The impact pressure (0.5 MPa) is constrained by the kinetic energy of the impact (1010-1012 J) estimated from the seismic energy generated by the impact. Results from the air blast simulations indicate that the second Happy Isles air blast (weak shock wave) traveled with an initial velocity above the local sound speed. The size and location of the first impact are thought to have injected <50 wt % dust into the atmosphere. This amount of dust lowered the local atmospheric sound speed to ???220 m/s. The discrepancy between calculated velocity data and field estimated velocity data (???220 m/s versus ???110 m/s) is attributed to energy dissipated by the downing of trees and additional entrainment of debris into the atmosphere not included in the calculations. Copyright 1999 by the American Geophysical Union.

  4. Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Morrissey, M. M.; Savage, W. Z.; Wieczorek, G. F.

    1999-10-01

    The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior of the second air blast that downed over 1000 trees, destroyed a bridge, demolished a snack bar, and caused one fatality and several injuries. Calculated velocities for the air blast from a two-phase, finite difference model are compared to velocities estimated from tree damage. From tornadic studies of tree damage, the air blast is estimated to have traveled <108-120 m/s within 50 m from the impact and decreased to <10-20 m/s within 500 m from the impact. The numerical model simulates the two-dimensional propagation of an air blast through a dusty atmosphere with initial conditions defined by the impact velocity and pressure. The impact velocity (105-107 m/s) is estimated from the Colorado Rockfall Simulation Program that simulates rockfall trajectories. The impact pressure (0.5 MPa) is constrained by the kinetic energy of the impact (1010-1012 J) estimated from the seismic energy generated by the impact. Results from the air blast simulations indicate that the second Happy Isles air blast (weak shock wave) traveled with an initial velocity above the local sound speed. The size and location of the first impact are thought to have injected <50 wt% dust into the atmosphere. This amount of dust lowered the local atmospheric sound speed to ˜220 m/s. The discrepancy between calculated velocity data and field estimated velocity data (˜220 m/s versus ˜110 m/s) is attributed to energy dissipated by the downing of trees and additional entrainment of debris into the atmosphere not included in the calculations.

  5. Laser-induced blast waves in air and their effect on monodisperse droplet chains of ethanol and kerosene

    NASA Astrophysics Data System (ADS)

    Gebel, G. C.; Mosbach, T.; Meier, W.; Aigner, M.

    2015-07-01

    Weak spherical blast waves in static air and their breakup of ethanol and Jet A-1 kerosene droplets were investigated. The blast waves were created by laser-induced air breakdowns at ambient temperature and pressure. In the first part of this study, they were visualized with schlieren imaging, and their trajectories were tracked with high temporal resolution. The laser pulse energy was varied to create blast waves of different strengths. Their initial energies were determined by the application of a numerical and a semi-empirical blast wave model. In the second part, monodisperse ethanol and kerosene droplet chains were injected. Their interaction with the blast waves was visualized by the application of shadowgraph imaging. The perpendicular distance of the breakdown origin toward the droplet chains was varied to study the effect on the fuel droplets as a function of the distance. Droplets within a few millimeters around the breakdown origin were disintegrated into two to three secondary droplets. The blast-induced flow velocities on the post-shock side and the corresponding Weber numbers were calculated from the data of a non-dimensional numerical simulation, and a close look was taken at the breakup process of the droplets. The analysis showed that the aerodynamic force of the blast-induced flow was sufficient to deform the droplets into disk-like shapes, but diminished too fast to accomplish breakup. Due to the release of strain energy, the deformed droplets relaxed, stretched into filaments and finally disintegrated by capillary pinching.

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

    SciTech Connect

    Sanders, Victor E; Zucker, Jonathan M; Mc Afee, John M; Tappan, Bryce C; Asay, Blaine W

    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.

  7. Numerical simulation of the fluid-structure interaction between air blast waves and soil structure

    NASA Astrophysics Data System (ADS)

    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.

  8. Changes in Ultrastructure and Sensory Characteristics on Electro-magnetic and Air Blast Freezing of Beef during Frozen Storage.

    PubMed

    Choi, Yun-Sang; Ku, Su-Kyung; Jeong, Ji-Yun; Jeon, Ki-Hong; Kim, Young-Boong

    2015-01-01

    The ultrastructure in the beef muscle of the electro-magnetic resonance and air blast freezing during the frozen storage, and the changes in the quality characteristics after thawing were evaluated. The size of ice crystal was small and evenly formed in the initial freezing period, and it showed that the size was increased as the storage period was elapsed (p<0.05). The beef stored by the electro-magnetic resonance freezing showed the size of ice crystal with a lower rate of increase than the air blast freezing during the frozen storage. The thawing loss of beef stored by the electro-magnetic resonance freezing was significantly lower than the air blast freezing during frozen storage (p<0.05), and it showed that the thawing loss of the round was higher than the loin. Water holding capacity decreased as the storage period became longer while the electro-magnetic resonance freezing was higher than the air blast on 8 month (p<0.05). As a result of sensory evaluation, the beef stored by the electro-magnetic resonance freezing did not show the difference until 4 months, and it showed higher acceptability in comparison with the beef stored by the air blast freezing. Thus, it is considered that the freezing method has an effect on the change in the ultrastructure and quality characteristics of the beef.

  9. Changes in Ultrastructure and Sensory Characteristics on Electro-magnetic and Air Blast Freezing of Beef during Frozen Storage

    PubMed Central

    2015-01-01

    The ultrastructure in the beef muscle of the electro-magnetic resonance and air blast freezing during the frozen storage, and the changes in the quality characteristics after thawing were evaluated. The size of ice crystal was small and evenly formed in the initial freezing period, and it showed that the size was increased as the storage period was elapsed (p<0.05). The beef stored by the electro-magnetic resonance freezing showed the size of ice crystal with a lower rate of increase than the air blast freezing during the frozen storage. The thawing loss of beef stored by the electro-magnetic resonance freezing was significantly lower than the air blast freezing during frozen storage (p<0.05), and it showed that the thawing loss of the round was higher than the loin. Water holding capacity decreased as the storage period became longer while the electro-magnetic resonance freezing was higher than the air blast on 8 month (p<0.05). As a result of sensory evaluation, the beef stored by the electro-magnetic resonance freezing did not show the difference until 4 months, and it showed higher acceptability in comparison with the beef stored by the air blast freezing. Thus, it is considered that the freezing method has an effect on the change in the ultrastructure and quality characteristics of the beef. PMID:26761797

  10. Hydrodynamic Modeling of Air Blast Propagation from the Humble Redwood Chemical High Explosive Detonations Using GEODYN

    SciTech Connect

    Chipman, V D

    2011-09-20

    Two-dimensional axisymmetric hydrodynamic models were developed using GEODYN to simulate the propagation of air blasts resulting from a series of high explosive detonations conducted at Kirtland Air Force Base in August and September of 2007. Dubbed Humble Redwood I (HR-1), these near-surface chemical high explosive detonations consisted of seven shots of varying height or depth of burst. Each shot was simulated numerically using GEODYN. An adaptive mesh refinement scheme based on air pressure gradients was employed such that the mesh refinement tracked the advancing shock front where sharp discontinuities existed in the state variables, but allowed the mesh to sufficiently relax behind the shock front for runtime efficiency. Comparisons of overpressure, sound speed, and positive phase impulse from the GEODYN simulations were made to the recorded data taken from each HR-1 shot. Where the detonations occurred above ground or were shallowly buried (no deeper than 1 m), the GEODYN model was able to simulate the sound speeds, peak overpressures, and positive phase impulses to within approximately 1%, 23%, and 6%, respectively, of the actual recorded data, supporting the use of numerical simulation of the air blast as a forensic tool in determining the yield of an otherwise unknown explosion.

  11. Characterization of biological particulate loads in metropolitan air

    Treesearch

    J. A. Snow; R. D. Schein; W. J. Moroz

    1977-01-01

    The atmospheric particulate load includes a wide range of naturally occurring particles of biological origin that serve as a reservoir of allergenic agents in respiratory disease. Improved knowledge of potential aeroallergens is needed by medical clinicians. Aims are to better characterize air spora, qualitatively and quantitatively, and determine daily (by hour)...

  12. Mechanical and histological characterization of trachea tissue subjected to blast-type pressures

    NASA Astrophysics Data System (ADS)

    Butler, B. J.; Bo, C.; Tucker, A. W.; Jardine, A. P.; Proud, W. G.; Williams, A.; Brown, K. A.

    2014-05-01

    Injuries to the respiratory system can be a component of polytrauma in blast-loading injuries. Tissues located at air-liquid interfaces, including such tissues in the respiratory system, are particularly vulnerable to damage by blast overpressures. There is a lack of information about the mechanical and cellular responses that contribute to the damage of this class of tissues subjected to the high strain rates associated with blast loading. Here, we describe the results of dynamic blast-like pressure loading tests at high strain rates on freshly harvested ex vivo trachea tissue specimens.

  13. Prediction of Air Conditioning Load Response for Providing Spinning Reserve - ORNL Report

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Ally, Moonis Raza; Rice, C Keith

    2009-02-01

    This report assesses the use of air conditioning load for providing spinning reserve and discusses the barriers and opportunities. Air conditioning load is well suited for this service because it often increases during heavy load periods and can be curtailed for short periods with little impact to the customer. The report also provides an appendix describing the ambient temperature effect on air conditioning load.

  14. A Combined Multi-Material Euler/LaGrange Computational Analysis of Blast Loading Resulting from Detonation of Buried Landmines

    DTIC Science & Technology

    2008-01-01

    detonation by-products) with the witness plate. Keywords Detonation, Shallow Buried Mine, Blast Loading, AUTODYN NOMENCLATURE Report...instrumentation. In our recent computational work [3] based on the use of AUTODYN , a general- purpose transient non-linear dynamics explicit simulation...modeling of the same physical problem using AUTODYN . In our follow-up work [12], the newly developed materials constitutive model for sand was used within

  15. Air blast circuit breaker noise and hearing loss: a multifactorial model for risk assessment.

    PubMed

    McBride, D I; Williams, S

    2000-04-01

    The assessment of the risk to hearing from impulse noise exposure may be a problem for the occupational physician because existing legislative and international noise exposure standards deal primarily with continuous noise, and are not valid in excess of the peak exposure limit of 200 pa (140 dB). Noise exposure in excess of this level, for example that due to firearms, is frequently perceived as harmful, but this is not necessarily the case, as impulse noise standards do, in fact, allow exposure with a maximum in the order of 6.3 kPa (170 dB). To illustrate this, a cross-sectional group of electrical transmission workers have been studied who were exposed to significant levels of impulse noise from air blast circuit breakers and firearms. Important hearing loss factors have been identified by means of a specially designed questionnaire. Using the Health & Safety Executive definition, the risk of hearing loss was determined by calculating prevalence odds ratios (ORs) for exposure to these factors. The OR for those with fewer than eight unprotected air blast circuit breaker exposures was 2.27 (95% confidence interval (CI), 1.01-5.08), whilst for those with more than eight exposures the OR was 2.10 (95% CI, 0.97-4.54). For firearm exposure, ORs of 1.61 (95% CI, 0.95-2.74) were noted in the medium exposure group and 2.05 (95% CI, 1.08-3.86) in the high exposure group. When all the factors were included in the model, the most significant factor was age. The study gives support to the impulse noise exposure criteria, confirming the borderline risk from air blast circuit breaker noise exposure and the relative safety of moderate gunfire exposure.

  16. Optimization of air-blast drying process for manufacturing Saccharomyces cerevisiae and non-Saccharomyces yeast as industrial wine starters.

    PubMed

    Lee, Sae-Byuk; Choi, Won-Seok; Jo, Hyun-Jung; Yeo, Soo-Hwan; Park, Heui-Dong

    2016-12-01

    Wine yeast (Saccharomyces cerevisiae D8) and non-Saccharomyces wine yeasts (Hanseniaspora uvarum S6 and Issatchenkia orientalis KMBL5774) were studied using air-blast drying instead of the conventional drying methods (such as freeze and spray drying). Skim milk-a widely used protective agent-was used and in all strains, the highest viabilities following air-blast drying were obtained using 10% skim milk. Four excipients (wheat flour, nuruk, artichoke powder, and lactomil) were evaluated as protective agents for yeast strains during air-blast drying. Our results showed that 7 g lactomil was the best excipient in terms of drying time, powder form, and the survival rate of the yeast in the final product. Finally, 7 types of sugars were investigated to improve the survival rate of air-blast dried yeast cells: 10% trehalose, 10% sucrose, and 10% glucose had the highest survival rate of 97.54, 92.59, and 79.49% for S. cerevisiae D8, H. uvarum S6, and I. orientalis KMBL5774, respectively. After 3 months of storage, S. cerevisiae D8 and H. uvarum S6 demonstrated good survival rates (making them suitable for use as starters), whereas the survival rate of I. orientalis KMBL5774 decreased considerably compared to the other strains. Air-blast dried S. cerevisiae D8 and H. uvarum S6 showed metabolic activities similar to those of non-dried yeast cells, regardless of the storage period. Air-blast dried I. orientalis KMBL5774 showed a noticeable decrease in its ability to decompose malic acid after 3 months of storage at 4 °C.

  17. Investigation of residential central air conditioning load shapes in NEMS

    SciTech Connect

    Hamachi LaCommare, Kristina; Marnay, Chris; Gumerman, Etan; Chan, Peter; Rosenquist, Greg; Osborn, Julie

    2002-05-01

    This memo explains what Berkeley Lab has learned about how the residential central air-conditioning (CAC) end use is represented in the National Energy Modeling System (NEMS). NEMS is an energy model maintained by the Energy Information Administration (EIA) that is routinely used in analysis of energy efficiency standards for residential appliances. As part of analyzing utility and environmental impacts related to the federal rulemaking for residential CAC, lower-than-expected peak utility results prompted Berkeley Lab to investigate the input load shapes that characterize the peaky CAC end use and the submodule that treats load demand response. Investigations enabled a through understanding of the methodology by which hourly load profiles are input to the model and how the model is structured to respond to peak demand. Notably, it was discovered that NEMS was using an October-peaking load shape to represent residential space cooling, which suppressed peak effects to levels lower than expected. An apparent scaling down of the annual load within the load-demand submodule was found, another significant suppressor of the peak impacts. EIA promptly responded to Berkeley Lab's discoveries by updating numerous load shapes for the AEO2002 version of NEMS; EIA is still studying the scaling issue. As a result of this work, it was concluded that Berkeley Lab's customary end-use decrement approach was the most defensible way for Berkeley Lab to perform the recent CAC utility impact analysis. This approach was applied in conjunction with the updated AEO2002 load shapes to perform last year's published rulemaking analysis. Berkeley Lab experimented with several alternative approaches, including modifying the CAC efficiency level, but determined that these did not sufficiently improve the robustness of the method or results to warrant their implementation. Work in this area will continue in preparation for upcoming rulemakings for the other peak coincident end uses, commercial

  18. Daily Air Temperature and Electricity Load in Spain.

    NASA Astrophysics Data System (ADS)

    Valor, Enric; Meneu, Vicente; Caselles, Vicente

    2001-08-01

    Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a `comfort interval' of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in the warm season. Two different temperature-derived variables that allow a better characterization of the observed relationship have been used: the heating and cooling degree-days. The regression of electricity data on them defines the heating and cooling demand functions, which show correlation coefficients of 0.79 and 0.87, and predicts electricity load with standard errors of estimate of ±4% and ±2%, respectively. The maximum elasticity of electricity demand is observed at 7 cooling degree-days and 9 heating degree-days, and the saturation points are reached at 11 cooling degree-days and 13 heating degree-days, respectively. These results are helpful in modeling electricity load behavior for predictive purposes.

  19. Multiscale Failure Analysis of Laminated Composite Panels Subjected to Blast Loading Using FEAMAC/Explicit

    NASA Technical Reports Server (NTRS)

    Pineda, Evan J.; Waas, Anthony M.; Berdnarcyk, Brett A.; Arnold, Steven M.; Collier, Craig S.

    2009-01-01

    This preliminary report demonstrates the capabilities of the recently developed software implementation that links the Generalized Method of Cells to explicit finite element analysis by extending a previous development which tied the generalized method of cells to implicit finite elements. The multiscale framework, which uses explicit finite elements at the global-scale and the generalized method of cells at the microscale is detailed. This implementation is suitable for both dynamic mechanics problems and static problems exhibiting drastic and sudden changes in material properties, which often encounter convergence issues with commercial implicit solvers. Progressive failure analysis of stiffened and un-stiffened fiber-reinforced laminates subjected to normal blast pressure loads was performed and is used to demonstrate the capabilities of this framework. The focus of this report is to document the development of the software implementation; thus, no comparison between the results of the models and experimental data is drawn. However, the validity of the results are assessed qualitatively through the observation of failure paths, stress contours, and the distribution of system energies.

  20. A 3D Computational Study on the Air-Blast Atomization of a Planar Liquid Layer

    NASA Astrophysics Data System (ADS)

    Chiodi, Robert; Desjardins, Olivier

    2016-11-01

    The air-blast atomization of a planar liquid layer is a complex fluid phenomenon involving the destabilization of a low speed liquid layer by a high speed gas coflow. While progress has been made in recent years on understanding the instability of the liquid surface, it remains difficult to accurately predict using stability analysis and requires special expertise and equipment to perform thorough experiments. Simulations provide an excellent way to conduct parametric studies to determine the effect of splitter plate geometry and momentum flux ratio on the frequency and wavelengths of instability, however, they are extremely difficult due to the high density ratio and large range of length and time scales present in the flow. Using an accurate conservative level set method in conjunction with a newly reformulated reinitialization equation, we perform 3D simulations of the air-blast atomization of a planar liquid layer and compare them to experiments. We then go on to explore the role momentum flux ratio plays in the longitudinal and transverse wavelengths of instability.

  1. Evaluation of brain tissue responses because of the underwash overpressure of helmet and faceshield under blast loading.

    PubMed

    Sarvghad-Moghaddam, Hesam; Rezaei, Asghar; Ziejewski, Mariusz; Karami, Ghodrat

    2017-01-01

    Head protective tools such as helmets and faceshields can induce a localized high pressure region on the skull because of the underwash of the blast waves. Whether this underwash overpressure can affect the brain tissue response is still unknown. Accordingly, a computational approach was taken to confirm the incidence of underwash with regards to blast direction, as well as examine the influence of this effect on the mechanical responses of the brain. The variation of intracranial pressure (ICP) as one of the major injury predictors, as well as the maximum shear stress were mainly addressed in this study. Using a nonlinear finite element (FE) approach, generation and interaction of blast waves with the unprotected, helmeted, and fully protected (helmet and faceshield protected) FE head models were modeled using a multi-material arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The underwash incidence overpressure was found to greatly change with the blast direction. Moreover, while underwash induced ICP (U-ICP) did not exceed the peak ICP of the unprotected head, it was comparable and even more than the peak ICP imposed on the protected heads by the primary shockwaves (Coup-ICP). It was concluded that while both helmet and faceshield protected the head against blast waves, the underwash overpressure affected the brain tissue response and altered the dynamic load experienced by the brain as it led to increased ICP levels at the countercoup site, imparted elevated skull flexure, and induced high negative pressure regions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Impact of blast induced transitory vibration and air-overpressure/noise on human brain--an experimental study.

    PubMed

    Raina, A K; Baheti, M; Haldar, A; Ramulu, M; Chakraborty, A K; Sahu, P B; Bandopadhayay, C

    2004-04-01

    Human response to blast induced ground vibration and air-overpressure/noise is a major concern of current mining activity. This is because the fact that mines are fast transgressing the habitats and people are getting educated. Consequently the response of humans is changing and expectedly will increase in days to come with no viable and economic alternative to blasting--an essential component of mining. The response of humans can be purely physiological or psychological in nature or combination of both depending upon the situation and conditions of mining. Where physiological response is documented in terms of effects on ears and lungs there is a meager amount or no literature available regarding effects of blasting on the brain. Moreover, the studies on transitory phenomenon like the effects of blasting on humans are rare in comparison to the whole body vibration studies. This study was designed to address the issues as a precursor to a major initiative. The preliminary investigations conducted with the monitoring of EEG responses of humans to vibration and air-overpressure/noise due to blasting revealed that there is no major response of the brain to transitory vibrations and noise.

  3. Brain injuries from blast.

    PubMed

    Bass, Cameron R; Panzer, Matthew B; Rafaels, Karen A; Wood, Garrett; Shridharani, Jay; Capehart, Bruce

    2012-01-01

    appropriate between species, many reported rodent blast TBI experiments using air shock tubes have blast overpressure conditions that are similar to human long-duration nuclear blasts, not high explosive blasts.

  4. OVERVIEW OF PRESSURE VESSEL DESIGN CRITERIA FOR INTERNAL DETONATION (BLAST) LOADING

    SciTech Connect

    T. A. DUFFEY; E. A. RODRIGUEZ

    2001-05-01

    applicable to all Containment Vessels, including those at LANL; or a combination of the two. This memo supplements information provided in the viewgraphs of the Presentation by E.A. Rodriguez to be given to the PVRC at the May Meeting. The Presentation is entitled, ''Design Criteria for Internal Detonation (Blast) Loading''.

  5. Emergency installation of an air-cooled trough at Dofasco`s No. 2 blast furnace

    SciTech Connect

    Zacharewicz, T.; Sharp, R.

    1995-07-01

    No. 2 blast furnace was put back into service on May 5, 1994, three years after it was shut down for an interim repair. Improvements had to be made to the casthouse floor to attain production rates required. The east trough was cast with low-moisture castable to allow holding iron for 10 days before a drain. After six months of operation, severe damage to the east trough sidewalls indicated that a major repair was required. Dofasco`s iron production business unit initiated the emergency east trough replacement project. The mandate was to engineer, fabricate and install a forced air-cooled trough to replace the existing conventional buried box and maintain operation and delivery of iron for steelmaking. The scope of the emergency repair from identification of the problem to first cast and performance of the trough will be reviewed.

  6. Chloride leaching from air pollution control residues solidified using ground granulated blast furnace slag.

    PubMed

    Lampris, Christos; Stegemann, Julia A; Cheeseman, Christopher R

    2008-11-01

    Ground granulated blast furnace slag (ggbs) has been used to solidify air pollution control (APC) residues obtained from a major UK energy-from-waste plant. Samples were prepared with ggbs additions between 10 and 50 wt% of total dry mass and water/solids ratios between 0.35 and 0.80. Consistence, setting time, compressive strength and leaching characteristics have been investigated. Results indicated that the highly alkaline nature of APC residues due to the presence of free lime can be used to activate ggbs hydration reactions. Increasing ggbs additions and reducing the water content resulted in increased compressive strengths, with 50 wt% ggbs samples having average 28 d strengths of 20.6 MPa. Leaching tests indicate low physical encapsulation and minimal chemical fixation of chloride in ggbs solidified APC residues. The results suggest that more than 50 wt% ggbs additions would be required to treat APC residues to meet the current waste acceptance criteria limits for chloride.

  7. Use of Faraday instabilities to enhance fuel pulverisation in air-blast atomisers

    NASA Astrophysics Data System (ADS)

    Boukra, Madjid; Cartellier, Alain; Ducasse, Éric; Gajan, Pierre; Lalo, Marie; Noel, Thomas; Strzelecki, Alain

    2009-06-01

    The atomization of liquids into a spray is an important process in many industrial applications and particularly in the aero-engine sector. Conventional air-blast injectors in aircraft engines today use aerodynamic shearing effects to atomize the liquid fuel. However, at operating conditions where the air velocity is below 30 m/s (such as ground start and high altitude restart) the atomization quality is poor. Consequently combustion is less efficient with high pollutant emissions. The objective of this study is to validate a new concept of injector which couples the shearing effects with the principle of ultrasonic atomization. The latter consists of using piezoelectric actuators to generate the oscillations of a wall in contact with the liquid film. This excitation perpendicular to the liquid film surface creates Faraday instabilities at the liquid/air interface. Amplitudes higher than a defined threshold value induce the break-up of ligaments and the formation of droplets. To cite this article: M. Boukra et al., C. R. Mecanique 337 (2009).

  8. Parametric analysis of the biomechanical response of head subjected to the primary blast loading--a data mining approach.

    PubMed

    Zhu, Feng; Kalra, Anil; Saif, Tal; Yang, Zaihan; Yang, King H; King, Albert I

    2016-01-01

    Traumatic brain injury due to primary blast loading has become a signature injury in recent military conflicts and terrorist activities. Extensive experimental and computational investigations have been conducted to study the interrelationships between intracranial pressure response and intrinsic or 'input' parameters such as the head geometry and loading conditions. However, these relationships are very complicated and are usually implicit and 'hidden' in a large amount of simulation/test data. In this study, a data mining method is proposed to explore such underlying information from the numerical simulation results. The heads of different species are described as a highly simplified two-part (skull and brain) finite element model with varying geometric parameters. The parameters considered include peak incident pressure, skull thickness, brain radius and snout length. Their interrelationship and coupling effect are discovered by developing a decision tree based on the large simulation data-set. The results show that the proposed data-driven method is superior to the conventional linear regression method and is comparable to the nonlinear regression method. Considering its capability of exploring implicit information and the relatively simple relationships between response and input variables, the data mining method is considered to be a good tool for an in-depth understanding of the mechanisms of blast-induced brain injury. As a general method, this approach can also be applied to other nonlinear complex biomechanical systems.

  9. Critical loads as a policy tool for protecting ecosystems from the effects of air pollutants

    Treesearch

    Douglas A. Burns; Tamara Blett; Richard Haeuber; Linda H. Pardo

    2008-01-01

    Framing the effects of air pollutants on ecosystems in terms of a "critical load" provides a meaningful approach for research scientists to communicate policy-relevant science to air-quality policy makers and natural resource managers. A critical-loads approach has been widely used to shape air-pollutant control policy in Europe since the 1980s, yet has only...

  10. Sealed piezoelectric energy harvester driven by hyperbaric air load

    NASA Astrophysics Data System (ADS)

    Wang, Yingting; Wang, Liang; Cheng, Tinghai; Song, Zhaoyang; Qin, Feng

    2016-01-01

    In this paper, a sealed piezoelectric energy harvester is fabricated to investigate the performance of the proposed harvester when driven by a hyperbaric air load. The harvester consists of a flexible piezoceramic patch and a closed chamber. The energy from the hyperbaric air can be harvested through the deformation of the lead zirconate titanate patch. A test system is built and a prototype device is tested under various experimental conditions. The test results show that the energy generation performance of the harvester can be tuned by varying its parameters. The output voltage shows an obvious increase with increasing cycle time. When the pressure increases, the output voltage is simultaneously reduced when the flow is fixed. The maximal output voltage and power across the 1000 kΩ resistor are 70.90 V and 9.30 mW, respectively. An effective power of 3.41 mW is measured across the 200 kΩ resistor at a pressure of 0.4 MPa and a cycle time of 0.8 s with a flow of 365 l/min.

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

    SciTech Connect

    Corona, Edmundo; Gullerud, Arne S.; Haulenbeek, Kimberly K.; Reu, Phillip L.

    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.

  12. Compressive strength after blast of sandwich composite materials

    PubMed Central

    Arora, H.; Kelly, M.; Worley, A.; Del Linz, P.; Fergusson, A.; Hooper, P. A.; Dear, J. P.

    2014-01-01

    Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene–acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3 m sized panels were subjected to blast of a Hopkinson–Cranz scaled distance of 3.02 m kg−1/3, 100 kg TNT equivalent at a stand-off distance of 14 m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411–413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast. PMID:24711494

  13. Compressive strength after blast of sandwich composite materials.

    PubMed

    Arora, H; Kelly, M; Worley, A; Del Linz, P; Fergusson, A; Hooper, P A; Dear, J P

    2014-05-13

    Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene-acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3 m sized panels were subjected to blast of a Hopkinson-Cranz scaled distance of 3.02 m kg(-1/3), 100 kg TNT equivalent at a stand-off distance of 14 m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411-413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast.

  14. Process for Design Optimization of Honeycomb Core Sandwich Panels for Blast Load Mitigation

    DTIC Science & Technology

    2012-12-01

    damage causing potential of the blast impulse. Though metal sandwich panels have been used for a long time in aircraft and other light weight struc...aluminum alloy with bilinear isotropic-hardening elastoplastic material model is used for the foil. Since the yield and ultimate strength of the AL5052...foil are very close, bilinear elastoplastic mate- rial model with very low tangent modulus is a reasonable approximation. The adhesive is modeled as

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

    DTIC Science & Technology

    2014-08-12

    not display a currently valid OMB control number. 1. REPORT DATE 12 AUG 2014 2. REPORT TYPE Journal Article 3. DATES COVERED 12-08-2014 to 12-08...Vehicle Occupants against Anti-Vehicular Landmine Effects, NATO RTO TECHNICAL REPORT TR-HFM-090, April 2007 2. XZ Zhang, WH Li, XL Gong. The rheology ...Mechanism of shear thickening investigated by a network model, Journal of Non-Newtonian Fluid Mechanics, 1995. 4. MS Hoo Fatt, H Surabhi. Blast

  16. Model for small arms fire muzzle blast wave propagation in air

    NASA Astrophysics Data System (ADS)

    Aguilar, Juan R.; Desai, Sachi V.

    2011-11-01

    Accurate modeling of small firearms muzzle blast wave propagation in the far field is critical to predict sound pressure levels, impulse durations and rise times, as functions of propagation distance. Such a task being relevant to a number of military applications including the determination of human response to blast noise, gunfire detection and localization, and gun suppressor design. Herein, a time domain model to predict small arms fire muzzle blast wave propagation is introduced. The model implements a Friedlander wave with finite rise time which diverges spherically from the gun muzzle. Additionally, the effects in blast wave form of thermoviscous and molecular relaxational processes, which are associated with atmospheric absorption of sound were also incorporated in the model. Atmospheric absorption of blast waves is implemented using a time domain recursive formula obtained from numerical integration of corresponding differential equations using a Crank-Nicholson finite difference scheme. Theoretical predictions from our model were compared to previously recorded real world data of muzzle blast wave signatures obtained by shooting a set different sniper weapons of varying calibers. Recordings containing gunfire acoustical signatures were taken at distances between 100 and 600 meters from the gun muzzle. Results shows that predicted blast wave slope and exponential decay agrees well with measured data. Analysis also reveals the persistency of an oscillatory phenomenon after blast overpressure in the recorded wave forms.

  17. Gas and drop behavior in reacting and non-reacting air-blast atomizer sprays

    NASA Technical Reports Server (NTRS)

    Mcdonell, Vincent G.; Samuelsen, Scott

    1991-01-01

    A detailed study of the two-phase flow produced by a gas-turbine air-blast atomizer is performed with the goal of identifying the interaction between the two phases for both nonreacting and reacting conditions. A two-component phase Doppler interferometry is utilized to characterize three flowfields produced by the atomizer: (1) the single-phase flow, (2) the two-phase nonreacting spray, and (3) the two-phase reacting spray. Measurements of the mean and fluctuating axial and azimuthal velocities for each phase are obtained. In addition, the droplet size distribution, volume flux, and concentration are measured. The results reveal the strong influence of the dispersed phase on the gas, and the influence of reaction on both the gas and the droplet field. The presence of the spray significantly alters the inlet condition of the atomizer. With this alteration quantified, it is possible to deduce that the inertia associated with the dispersed phase damps the fluctuating velocities of the gas. Reaction reduces the volume flux of the droplets, broadens the local volume distribution of the droplets in the region of the reaction zone, increases the axial velocities and radial spread of the gas, and increases the anisotropy in the region of the reaction zone.

  18. Gas and drop behavior in reacting and non-reacting air-blast atomizer sprays

    NASA Astrophysics Data System (ADS)

    McDonell, Vincent G.; Samuelsen, Scott

    1991-10-01

    A detailed study of the two-phase flow produced by a gas-turbine air-blast atomizer is performed with the goal of identifying the interaction between the two phases for both nonreacting and reacting conditions. A two-component phase Doppler interferometry is utilized to characterize three flowfields produced by the atomizer: (1) the single-phase flow, (2) the two-phase nonreacting spray, and (3) the two-phase reacting spray. Measurements of the mean and fluctuating axial and azimuthal velocities for each phase are obtained. In addition, the droplet size distribution, volume flux, and concentration are measured. The results reveal the strong influence of the dispersed phase on the gas, and the influence of reaction on both the gas and the droplet field. The presence of the spray significantly alters the inlet condition of the atomizer. With this alteration quantified, it is possible to deduce that the inertia associated with the dispersed phase damps the fluctuating velocities of the gas. Reaction reduces the volume flux of the droplets, broadens the local volume distribution of the droplets in the region of the reaction zone, increases the axial velocities and radial spread of the gas, and increases the anisotropy in the region of the reaction zone.

  19. Energy and momentum transfer to a 'fully-clamped' elastic plate in an air-blast

    NASA Astrophysics Data System (ADS)

    Yuan, Y.; Tan, P. J.

    2013-07-01

    The momentum transfer by a planar wave impinging upon a rigid, free-standing plate in water, a largely incompressible medium, is well understood [1]. Kambouchev et al. [2] extended the results of Taylor [1] to include the nonlinear effects of compressibility whilst Hutchinson [3] has recently addressed the issues of energy and momentum transfer to a rigid, free-standing plate. In this paper, key conclusions from the aforementioned studies are critically re-examined in the context of a 'fully-clamped' elastic plate. The dynamic response of an elastic plate is represented by an equivalent single-degree-of-freedom (SDOF) system. A numerical method based on a Lagrangian formulation of the Euler equations of compressible flow and conventional shock-capturing techn iques, similar to that employed in [2, 3], were employed to solve numerically the interaction between the air blast wave and elastic plate. Particular emphasis is placed on elucidating the energy and momentum transfer to a 'fully-clamped' elastic plate compared to its rigid, free-standing counterpart, and on whether enhancement in the beneficial effects of FSI as a result of fluid compressibility remains and to what extent.

  20. Simulation Engine for Fluid Solid Interaction Problems and its Application to the Modelling of Air Blast Hazards in Block Cave Mining.

    NASA Astrophysics Data System (ADS)

    Galindo Torres, S. A.; Scheuermann, A.; Ruest, M.

    2016-12-01

    Air blasts that may occur in a block caving mining operation represent a significant hazard for personnel as well as to mining infrastructure. Uncontrolled caving of a large volume of broken rock into a mine void causes compression of the air within, forcing it to flow at high velocities into connecting tunnels such as extraction points beneath the cave or observation points intersecting the cave. This high velocity flow of air can cause injury to personnel and significant damage to equipment. In this presentation, we introduce a simulation engine for the air blast problem. The solid material is modelled using the Discrete Element Method (DEM) and the fluid (air) is modelled using the Lattice Boltzmann Method (LBM). The combined DEM-LBM approach has been introduced by our group at the University of Queensland[1]. LBM allows us to introduce an appropriate equation of state for the air that simulates compressibility as a function of the speed of sound. Validation examples are presented to justify the use of this tool for an air blasting situation. A section view of one simulation is provided in Fig 1. An investigation into the risk of developing air pockets as a function of fragment size distribution is also conducted and described. The fragment size distribution can be assessed during mining and the risk of air pockets forming (and consequently of air blast occurring) can be deduced and mitigation measures put in place. The effect of other key variables that can be determined from geotechnical investigations, such as fracture frequency, are also systematically explored. It is expected that the results of this study can elucidate key features of the air blasting phenomenon in order to formulate safer mining protocols. references 1. Galindo-Torres, S.A., A coupled Discrete Element Lattice Boltzmann Method for the simulation of fluid-solid interaction with particles of general shapes. Computer Methods in Applied Mechanics and Engineering, 2013. 265(0): p. 107-119.

  1. Grasping From the Air: Hovering Capture and Load Stability

    DTIC Science & Technology

    2010-01-01

    examples of flying vehicles physically interacting with objects have been demonstrated, such as in- flight refueling [1, 2] and the transport of slung loads ...Payload Mass While several autonomous helicopters have flown with tethered loads [[3],[5],[6

  2. Spinning Reserve from Hotel Air Conditioning Load - SHORT VERSION

    SciTech Connect

    Kueck, John D; Kirby, Brendan J

    2008-01-01

    Even though preliminary tests were not conducted during times of highest system or hotel loading during the summer, they showed that hotel load can be curtailed by 22 to 37 percent depending on the outdoor temperature and time of day. Full response occurred in 12 to 60 seconds from when the system operator's command to shed load was issued and the load drop was very rapid.

  3. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... rock face is approaching mixed face, and when tunnel excavation is in mixed face, blasting shall be... tunnel excavation in rock face approaches mixed face, to determine the general nature and extent of rock...

  4. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... rock face is approaching mixed face, and when tunnel excavation is in mixed face, blasting shall be... tunnel excavation in rock face approaches mixed face, to determine the general nature and extent of rock...

  5. Blast Performance of Four Armour Materials

    DTIC Science & Technology

    2013-08-01

    conventional vehicle armour materials for performance under blast loading. The parameters measured were resistance to deformation, mechanical toughness and......energy absorption. B steel had high toughness but showed significant deformation under blast loading; particularly when subjected to multiple hits

  6. Air Pollution Critical Loads in the U.S.: Past, Present and Future

    NASA Astrophysics Data System (ADS)

    Blett, T. F.

    2012-12-01

    "Critical loads" describe the amount of air pollution initiating harmful changes in sensitive ecosystems. Critical loads generally have both a "science" component, describing the amount of deposition needed to alter chemical indicators (such as surface water acid neutralizing capacity) or biological endpoints (such as lichen biodiversity) and a "policy" component where critical loads are evaluated and utilized to help make land management or regulatory decisions. Critical loads science and policy have both made substantial headway in the U.S. over the past decade. For example, a recent review of critical loads of nitrogen cited over 300 published papers relevant to critical loads development in the U.S. The National Atmospheric Deposition Program's Critical Loads Science Subcommittee (CLAD) has recently synthesized most available U.S. critical loads data into a national-scale database and used it to develop maps for modeled surface water acidification, modeled soil acidification, and empirically derived excess nitrogen effects. Air quality regulators and land managers are increasingly using critical loads, in conjunction with policy objectives, to establish goals (target loads) for deposition reductions needed to improve sensitive resource conditions in impacted areas. These goals help focus air pollution emissions reduction efforts where they will be most effective. We will discuss critical loads history in the U.S., provide an overview of some of the most recent national-scale critical loads products, and outline future needs.

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

    SciTech Connect

    Taylor, Paul A.

    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.

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

    DTIC Science & Technology

    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...Mostafiz R Chowdhury A reprint from Journal of the Mechanical Behavior of Biomedical Materials , 2007;74:358–364...ARL-RP-0607 ● SEP 2017 US Army Research Laboratory Mechanical Characterization and Finite Element Implementation of the Soft Materials

  9. Experimental Studies of Mitigation Materials for Blast Induced Tbi

    NASA Astrophysics Data System (ADS)

    Alley, M. D.; Son, S. F.; Christou, G.; Goel, R.; Young, L.

    2009-12-01

    The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the material to reduce the damage caused by the blast. Several methods of energy transfer in blast wave flows are expected including: material interfaces with impedance mismatches, density changes in a given material, internal shearing, and particle fracture. Our hypothesis is that the greatest energy transfer within the obstructing material will yield the greatest mitigation effects to the blast. Sample configurations of foam were varied to introduce material interfaces and filler materials with varying densities and impedances (liquids and powders). The samples were dynamically loaded using a small scale blast produced by an explosive driven shock tube housing gram-scale explosive charges. The transmitted blast profiles were analyzed for variations in impulse characteristics and frequency components as compared to standard free field profiles. The results showed a rounding effect of the transmitted blast profile for all samples with the effects of the high density fillers surpassing all others tested. These results lead to a conclusion that low porosity, high density materials offer superior attenuation by reducing air blast features and spatially distributing the transmitted wave.

  10. Computational Simulation of the Mechanical Response of Brain Tissue under Blast Loading

    PubMed Central

    Laksari, Kaveh; Assari, Soroush; Seibold, Benjamin; Sadeghipour, Keya; Darvish, Kurosh

    2014-01-01

    In the present study, numerical simulations of nonlinear wave propagation and shock formation in brain tissue have been presented and a new mechanism of injury for Blast-Induced Neurotrauma (BINT) is proposed. A quasilinear viscoelastic (QLV) constitutive material model was used that encompasses the nonlinearity as well as the rate dependence of the tissue relevant to BINT modeling. A one-dimensional model was implemented using the discontinuous Galerkin -finite element method and studied with displacement-input and pressure-input boundary conditions. The model was validated against LS-DYNA finite element code and theoretical results for speci c conditions that resulted in shock wave formation. It was shown that a continuous wave can become a shock wave as it propagates in the QLV brain tissue when the initial changes in acceleration are beyond a certain limit. The high spatial gradient of stress and strain at the shock front cause large relative motions at the cellular scale at high temporal rates even when the maximum stresses and strains are relatively low. This gradient-induced local deformation may occur away from the boundary and is proposed as a contributing factor to the diffuse nature of BINT. PMID:25205088

  11. Computational simulation of the mechanical response of brain tissue under blast loading.

    PubMed

    Laksari, Kaveh; Assari, Soroush; Seibold, Benjamin; Sadeghipour, Keya; Darvish, Kurosh

    2015-06-01

    In the present study, numerical simulations of nonlinear wave propagation and shock formation in brain tissue have been presented and a new mechanism of injury for blast-induced neurotrauma (BINT) is proposed. A quasilinear viscoelastic (QLV) constitutive material model was used that encompasses the nonlinearity as well as the rate dependence of the tissue relevant to BINT modeling. A one-dimensional model was implemented using the discontinuous Galerkin finite element method and studied with displacement- and pressure-input boundary conditions. The model was validated against LS-DYNA finite element code and theoretical results for specific conditions that resulted in shock wave formation. It was shown that a continuous wave can become a shock wave as it propagates in the QLV brain tissue when the initial changes in acceleration are beyond a certain limit. The high spatial gradient of stress and strain at the shock front cause large relative motions at the cellular scale at high temporal rates even when the maximum stresses and strains are relatively low. This gradient-induced local deformation may occur away from the boundary and is proposed as a contributing factor to the diffuse nature of BINT.

  12. 29 CFR 1926.912 - Underwater blasting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... nonsparking metal loading tube when tube is necessary. (d) No blast shall be fired while any vessel under way... within 1,500 feet shall be notified before a blast is fired. (e) No blast shall be fired while any... in progress, signals and arrangements shall be agreed upon to assure that no blast shall be...

  13. 29 CFR 1926.912 - Underwater blasting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... nonsparking metal loading tube when tube is necessary. (d) No blast shall be fired while any vessel under way... within 1,500 feet shall be notified before a blast is fired. (e) No blast shall be fired while any... in progress, signals and arrangements shall be agreed upon to assure that no blast shall be...

  14. 29 CFR 1926.912 - Underwater blasting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... nonsparking metal loading tube when tube is necessary. (d) No blast shall be fired while any vessel under way... within 1,500 feet shall be notified before a blast is fired. (e) No blast shall be fired while any... in progress, signals and arrangements shall be agreed upon to assure that no blast shall be...

  15. Experimental and numerical correlation of a scaled containment vessel subjected to an internal blast load

    SciTech Connect

    Romero, C.; Benner, J.C.; Berkbigler, L.W.

    1997-02-01

    Los Alamos National Laboratory is currently in the design phase of a large Containment System that will be used to contain hydrodynamic experiments. The system in question is being designed to elastically withstand a 50 kg internal high explosive (PBX-9501) detonation. A one-tenth scaled model of the containment system was fabricated and used to obtain experimental results of both pressure loading and strain response. The experimental data are compared with numerical predictions of pressure loading and strain response obtained from an Eulerian hydrodynamic code (MESA-2D) and an explicit, non-linear finite element code (LLNL DYNA3D). The two-dimensional pressure predictions from multiple hydrodynamic simulations are used as loading in the structural simulation. The predicted pressure histories and strain response compare well with experimental results at several locations.

  16. Migration of biodynamic response to vibratory and blast-induced shock loads using magnetorheological seat suspensions

    NASA Astrophysics Data System (ADS)

    Choi, Young-Tai; Wereley, Norman M.

    2003-08-01

    This study investigates biodynamic response mitigation to three different excitations of sinusoidal and random vibrations and shock load using a magnetorheological (MR) seat suspension. In doing so, an MR seat suspension model for military vehicles, with a detailed lumped parameter model of the human body, was developed. The lumped parameter model of the human body consists of four parts: pelvis, upper torso, viscera and head. From the model, the governing equation of motion of the MR seat suspension considering the human body was derived. Based on this equation, a semi-active nonlinear optimal control algorithm appropriate for the MR seat suspension was developed. The simulated control performance of the MR seat suspension was evaluated under three different excitations of sinusoidal and random vibration and tremendous shock load due to a mine explosion. In addition, the mitigation of injuries to humans due to such shock load was also evaluated and compared with the passive seat suspension using a passive hydraulic damper.

  17. A new formulation for air-blast fluid-structure interaction using an immersed approach: part II—coupling of IGA and meshfree discretizations

    NASA Astrophysics Data System (ADS)

    Bazilevs, Y.; Moutsanidis, G.; Bueno, J.; Kamran, K.; Kamensky, D.; Hillman, M. C.; Gomez, H.; Chen, J. S.

    2017-07-01

    In this two-part paper we begin the development of a new class of methods for modeling fluid-structure interaction (FSI) phenomena for air blast. We aim to develop accurate, robust, and practical computational methodology, which is capable of modeling the dynamics of air blast coupled with the structure response, where the latter involves large, inelastic deformations and disintegration into fragments. An immersed approach is adopted, which leads to an a-priori monolithic FSI formulation with intrinsic contact detection between solid objects, and without formal restrictions on the solid motions. In Part I of this paper, the core air-blast FSI methodology suitable for a variety of discretizations is presented and tested using standard finite elements. Part II of this paper focuses on a particular instantiation of the proposed framework, which couples isogeometric analysis (IGA) based on non-uniform rational B-splines and a reproducing-kernel particle method (RKPM), which is a meshfree technique. The combination of IGA and RKPM is felt to be particularly attractive for the problem class of interest due to the higher-order accuracy and smoothness of both discretizations, and relative simplicity of RKPM in handling fragmentation scenarios. A collection of mostly 2D numerical examples is presented in each of the parts to illustrate the good performance of the proposed air-blast FSI framework.

  18. A new formulation for air-blast fluid-structure interaction using an immersed approach. Part I: basic methodology and FEM-based simulations

    NASA Astrophysics Data System (ADS)

    Bazilevs, Y.; Kamran, K.; Moutsanidis, G.; Benson, D. J.; Oñate, E.

    2017-07-01

    In this two-part paper we begin the development of a new class of methods for modeling fluid-structure interaction (FSI) phenomena for air blast. We aim to develop accurate, robust, and practical computational methodology, which is capable of modeling the dynamics of air blast coupled with the structure response, where the latter involves large, inelastic deformations and disintegration into fragments. An immersed approach is adopted, which leads to an a-priori monolithic FSI formulation with intrinsic contact detection between solid objects, and without formal restrictions on the solid motions. In Part I of this paper, the core air-blast FSI methodology suitable for a variety of discretizations is presented and tested using standard finite elements. Part II of this paper focuses on a particular instantiation of the proposed framework, which couples isogeometric analysis (IGA) based on non-uniform rational B-splines and a reproducing-kernel particle method (RKPM), which is a Meshfree technique. The combination of IGA and RKPM is felt to be particularly attractive for the problem class of interest due to the higher-order accuracy and smoothness of both discretizations, and relative simplicity of RKPM in handling fragmentation scenarios. A collection of mostly 2D numerical examples is presented in each of the parts to illustrate the good performance of the proposed air-blast FSI framework.

  19. A new formulation for air-blast fluid-structure interaction using an immersed approach: part II—coupling of IGA and meshfree discretizations

    NASA Astrophysics Data System (ADS)

    Bazilevs, Y.; Moutsanidis, G.; Bueno, J.; Kamran, K.; Kamensky, D.; Hillman, M. C.; Gomez, H.; Chen, J. S.

    2017-03-01

    In this two-part paper we begin the development of a new class of methods for modeling fluid-structure interaction (FSI) phenomena for air blast. We aim to develop accurate, robust, and practical computational methodology, which is capable of modeling the dynamics of air blast coupled with the structure response, where the latter involves large, inelastic deformations and disintegration into fragments. An immersed approach is adopted, which leads to an a-priori monolithic FSI formulation with intrinsic contact detection between solid objects, and without formal restrictions on the solid motions. In Part I of this paper, the core air-blast FSI methodology suitable for a variety of discretizations is presented and tested using standard finite elements. Part II of this paper focuses on a particular instantiation of the proposed framework, which couples isogeometric analysis (IGA) based on non-uniform rational B-splines and a reproducing-kernel particle method (RKPM), which is a meshfree technique. The combination of IGA and RKPM is felt to be particularly attractive for the problem class of interest due to the higher-order accuracy and smoothness of both discretizations, and relative simplicity of RKPM in handling fragmentation scenarios. A collection of mostly 2D numerical examples is presented in each of the parts to illustrate the good performance of the proposed air-blast FSI framework.

  20. A new formulation for air-blast fluid-structure interaction using an immersed approach. Part I: basic methodology and FEM-based simulations

    NASA Astrophysics Data System (ADS)

    Bazilevs, Y.; Kamran, K.; Moutsanidis, G.; Benson, D. J.; Oñate, E.

    2017-03-01

    In this two-part paper we begin the development of a new class of methods for modeling fluid-structure interaction (FSI) phenomena for air blast. We aim to develop accurate, robust, and practical computational methodology, which is capable of modeling the dynamics of air blast coupled with the structure response, where the latter involves large, inelastic deformations and disintegration into fragments. An immersed approach is adopted, which leads to an a-priori monolithic FSI formulation with intrinsic contact detection between solid objects, and without formal restrictions on the solid motions. In Part I of this paper, the core air-blast FSI methodology suitable for a variety of discretizations is presented and tested using standard finite elements. Part II of this paper focuses on a particular instantiation of the proposed framework, which couples isogeometric analysis (IGA) based on non-uniform rational B-splines and a reproducing-kernel particle method (RKPM), which is a Meshfree technique. The combination of IGA and RKPM is felt to be particularly attractive for the problem class of interest due to the higher-order accuracy and smoothness of both discretizations, and relative simplicity of RKPM in handling fragmentation scenarios. A collection of mostly 2D numerical examples is presented in each of the parts to illustrate the good performance of the proposed air-blast FSI framework.

  1. Emission of formaldehyde by particleboard : effect of ventilation rate and loading on air-contamination levels

    Treesearch

    George E. Myers; Muneo Nagaoka

    1981-01-01

    Dynamic tests for determining the formaldehyde emission behavior of UF-bonded boards involve the measurement of formaldehyde concentration in the air within a vessel which contains a specified board loading L (m2 of board area per m3 of vessel free volume) and is being ventilated at a specified air exchange rate N (hr.-1). Such tests constitute a primary...

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

    DTIC Science & Technology

    1959-06-05

    Retrnles 6 And ’, be vubotantiAted for an undergrowid semicircular arch. then - ruth an arth would b~e otubjected to bending. and its ultimate load...CONCLUSIONS and RECOIVENDATIONS 5.1 CONCLUSIONS The following conclusions are babed on the behaior of :he soil-struc.ture combination de- scribed

  3. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... rock face is approaching mixed face, and when tunnel excavation is in mixed face, blasting shall be performed with light charges and with light burden on each hole. Advance drilling shall be performed as tunnel excavation in rock face approaches mixed face, to determine the general nature and extent of...

  4. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... rock face is approaching mixed face, and when tunnel excavation is in mixed face, blasting shall be performed with light charges and with light burden on each hole. Advance drilling shall be performed as tunnel excavation in rock face approaches mixed face, to determine the general nature and extent of...

  5. Blast furnace stove control

    SciTech Connect

    Muske, K.R.; Hansen, G.A.; Howse, J.W.; Cagliostro, D.J.; Chaubal, P.C.

    1998-12-31

    This paper outlines the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed. It is then used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The controller also considers maximum and minimum temperature constraints within the stove.

  6. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2016-12-01

    laser scanning microscopy of the epithelial nerve structure in the human cornea. Graefe’s Archive for Clinical and Experimental Ophthalmology, 245(4...geometry of the lumbar spine disc was simplified for the simulations. The annulus fibrosus was modeled as an ellipse with a major axis of 0.02646 m and a...properties better predicts biomechanical behavior of lumbar discs subjected to dynamic loading. Journal of Biomechanics, vol. 40, pp. 1981–1987. Zhu, Q

  7. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2015-10-01

    mature and ever-improving surgical technology and procedures. Figure 1. Eye cross-section. www.nei.nih.gov. The hypothesis of the research is that an...traumatic cataract is formed in the combat soldier, and in turn improve our understanding of traumatic cataract in civilians whose eyes are subjected to...developing finite element models that can be used to simulate experimental test conditions, as well as physiologically -accurate loading conditions during

  8. Novel Approach to Conducting Blast Load Analyses Using Abaqus/Explicit-CEL

    DTIC Science & Technology

    2010-05-01

    ground burst of a cylindrical projectile filled with Comp-B explosive at 6500ft elevation– i.e. not TNT, not spherical, not free air, not uncased...11 reflect off the slanted roof at the rear of the vehicle before impacting the armor panels. As a...the armor panels and brackets were meshed using SC8R 8-node continuum shell elements. The remainder of the brackets and the windows were meshed

  9. The Shock and Vibration Bulletin. Part 4. Impact, Packaging and Shipping, Blast and Impulsive Loading

    DTIC Science & Technology

    1975-06-01

    Force Armament Laboratory, Eglin Air Force Base, Florida iII JI -A MATRIX STRUCTURAL DYNAMIC MODEL OF PARACHUTE THERMAL COVER EJECTION BY PYROTECHNIC...OF PARACHUTE THERMAL COVER EJECTION BY PYROTECHNIC DEVICES A. 2. Barniskia and l. A. Romanzi General Electric Co. 3t-entry and Environmental Systems...for predicting separation velocities of a flexible thermal cover ejected by four cartridge type pyro- technic devices. The method developed consisted of

  10. A Manual for the Prediction of Blast and Fragment Loadings on Structures

    DTIC Science & Technology

    1981-08-15

    PROPERTIES OF MATERIALS 7 . 1 I n t r o d u c t i o n 7.2 P r o p e r t i e s of Materials o f Cons t ruc t ion Under D y n a m i c Loading...Appendix A PROPERTIES OF EXPLOSIVES B SELECTED BIBLIOGRAPHY C UNIT CONVERSION TABLES 8-25 8- 25 8- 26 8- 3 1 8- 32 8- 32 8- 33 8- 34 8...Explosives and Explosive Chemicals ITEM PROPERTY 1 PHYSICAL PROPERTIES Common N a m e Chemical N a m e Formulation Color Phys ica l S ta te

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

    PubMed

    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.

  12. Robotic Water Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

    1983-01-01

    Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

  13. Robotic Water Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

    1983-01-01

    Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

  14. Structures to Resist the Effects of Accidental Explosions. Volume 2. Blast, Fragment, and Shock Loads

    DTIC Science & Technology

    1986-12-01

    parameters for a spherical TNT explosion in fret ’ air at sea level 1,000 t0 500 50 100 10w KI 50 5,.~ 5 0.5 L /W"/3 0.1. SCLE . ITAC Z Pi 1 a SCAL...1 G10 E 30 10010 w tox x C, 0. <A P-J to I I _ SCALED VENT AREA A/ V 2 / 3 Figure 2-154 Sca led gai mp1c WV 0.002, i Wi 100) 10000- -- ’S ~10 E L U

  15. Development of production scheme for the blast-wave loading of metal to harden bolt holes in rails

    NASA Astrophysics Data System (ADS)

    Churyumova, I. A.; Dov'ysh, S. G.

    1993-09-01

    Bolt holes in rails should be blast-hardened without residual deformation or with the aim of minimal deformation; metal settlement above 3% causes macro- and microfailure of the surface and a reduction in longevity.

  16. Influence of ambient air pressure on the energy conversion of laser-breakdown induced blast waves

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2013-09-01

    Influence of ambient pressure on energy conversion efficiency from a Nd : glass laser pulse (λ = 1.053 µm) to a laser-induced blast wave was investigated at reduced pressure. Temporal incident and transmission power histories were measured using sets of energy meters and photodetectors. A half-shadowgraph half-self-emission method was applied to visualize laser absorption waves. Results show that the blast energy conversion efficiency ηbw decreased monotonically with the decrease in ambient pressure. The decrease was small, from 40% to 38%, for the pressure change from 101 kPa to 50 kPa, but the decrease was considerable, to 24%, when the pressure was reduced to 30 kPa. Compared with a TEA-CO2-laser-induced blast wave (λ = 10.6 µm), higher fraction absorption in the laser supported detonation regime ηLSD of 90% was observed, which is influenced slightly by the reduction of ambient pressure. The conversion fraction ηbw/ηLSD≈90% was achieved at pressure >50 kPa, which is significantly higher than that in a CO2 laser case.

  17. Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2000-01-01

    This paper introduces a simple "Rule of Thumb" (ROT) method to estimate the load capacity of foil air journal bearings, which are self-acting compliant-surface hydrodynamic bearings being considered for Oil-Free turbo-machinery applications such as gas turbine engines. The ROT is based on first principles and data available in the literature and it relates bearing load capacity to the bearing size and speed through an empirically based load capacity coefficient, D. It is shown that load capacity is a linear function of bearing surface velocity and bearing projected area. Furthermore, it was found that the load capacity coefficient, D, is related to the design features of the bearing compliant members and operating conditions (speed and ambient temperature). Early bearing designs with basic or "first generation" compliant support elements have relatively low load capacity. More advanced bearings, in which the compliance of the support structure is tailored, have load capacities up to five times those of simpler designs. The ROT enables simplified load capacity estimation for foil air journal bearings and can guide development of new Oil-Free turbomachinery systems.

  18. Experimental assessment of air permeability in a concrete shear wall subjected to simulated seismic loading

    SciTech Connect

    Girrens, S.P.; Farrar, C.R.

    1991-07-01

    A safety concern for the proposed Special Nuclear Materials Laboratory (SNML) facility at the Los Alamos National Laboratory was air leakage from the facility if it were to experience a design basis earthquake event. To address this concern, a study was initiated to estimate air leakage, driven by wind-generated pressure gradients, from a seismically damaged concrete structure. This report describes a prototype experiment developed and performed to measure the air permeability in a reinforced concrete shear wall, both before and after simulated seismic loading. A shear wall test structure was fabricated with standard 4000-psi concrete mix. Static load-cycle testing was used to simulate earthquake loading. Permeability measurements were made by pressurizing one side of the shear wall above atmospheric conditions and recording the transient pressure decay. As long as the structure exhibited linear load displacement response, no variation in the air permeability was detected. However, experimental results indicate that the air permeability in the shear wall increased by a factor of 40 after the wall had been damaged (cracked). 17 figs., 8 tabs.

  19. Comfort air temperature influence on heating and cooling loads of a residential building

    NASA Astrophysics Data System (ADS)

    Stanciu, C.; Șoriga, I.; Gheorghian, A. T.; Stanciu, D.

    2016-08-01

    The paper presents the thermal behavior and energy loads of a two-level residential building designed for a family of four, two adults and two students, for different inside comfort levels reflected by the interior air temperature. Results are intended to emphasize the different thermal behavior of building elements and their contribution to the building's external load. The most important contributors to the building thermal loss are determined. Daily heating and cooling loads are computed for 12 months simulation in Bucharest (44.25°N latitude) in clear sky conditions. The most important aspects regarding sizing of thermal energy systems are emphasized, such as the reference months for maximum cooling and heating loads and these loads’ values. Annual maximum loads are encountered in February and August, respectively, so these months should be taken as reference for sizing thermal building systems, in Bucharest, under clear sky conditions.

  20. A Method to Exchange Air Nitrogen Emission Reductions for Watershed Nitrogen Load Reductions

    EPA Science Inventory

    Presentation of the method developed for the Chesapeake Bay Program to estimate changes in nitrogen loading to Chesapeake due to changes in Bay State state-level nitrogen oxide emissions to support air-water trading by the Bay States. Type for SticsUnder AMAD Application QAPP, QA...

  1. A Method to Exchange Air Nitrogen Emission Reductions for Watershed Nitrogen Load Reductions

    EPA Science Inventory

    Presentation of the method developed for the Chesapeake Bay Program to estimate changes in nitrogen loading to Chesapeake due to changes in Bay State state-level nitrogen oxide emissions to support air-water trading by the Bay States. Type for SticsUnder AMAD Application QAPP, QA...

  2. Opportunities to Reduce Air-Conditioning Loads Through Lower Cabin Soak Temperatures

    SciTech Connect

    Farrington, R.; Cuddy, M.; Keyser, M.; Rugh, J.

    1999-07-12

    Air-conditioning loads can significantly reduce electric vehicle (EV) range and hybrid electric vehicle (HEV) fuel economy. In addition, a new U. S. emissions procedure, called the Supplemental Federal Test Procedure (SFTP), has provided the motivation for reducing the size of vehicle air-conditioning systems in the United States. The SFTP will measure tailpipe emissions with the air-conditioning system operating. If the size of the air-conditioning system is reduced, the cabin soak temperature must also be reduced, with no penalty in terms of passenger thermal comfort. This paper presents the impact of air-conditioning on EV range and HEV fuel economy, and compares the effectiveness of advanced glazing and cabin ventilation. Experimental and modeled results are presented.

  3. Application of ground vibration frequency spectrum analysis as a tool for optimizing the blast design in large open pit mines

    SciTech Connect

    Rao, K.R.

    1994-12-31

    This paper explains the methodology for assessing the efficiency of rockmass fragmentation by explosive blasting, from ground vibration frequency spectrum analysis of the blast event. Explosives are used in the mining, quarrying and construction industries for fragmenting rockmass to a suitable size. When an explosive charge is detonated, in addition to fragmenting the rockmass, it will also generate ground vibration and air vibrations. Efficiency of a blast depend upon percentage of blast energy wasted in generating ground vibrations and air vibrations. This in turn will depend upon rockmass characteristics, amount of explosive energy used per delay and spatial distribution of explosive in the rockmass. Ground vibrations and air vibrations, arising out of explosive detonation in a rockmass, could be captured by micro-computer based engineering seismograph and sound level meter. Typical frequency range indicative of efficient rockmass fragmentation for a particular rockmass can be identified from ground vibration frequency spectra analysis of the blast event on a personal computer applying Fast Fourier transforms (FFT). The typical frequency range indicative of efficient rockmass fragmentation depends upon rockmass impedance and can be estimated from rockmass characteristics and monitoring few trial blasts. Blast event efficiency is estimated by comparing the typical frequency range with the dominant frequency range of the blast event record. A large number of blast events monitored and analyzed by the author in different rockmass formations and correlation of the results with observations made while fragmented material is lifted and loaded into trucks indicated that ground vibration frequency spectrum analysis could be used as a reliable and cost effective tool for assessing the blasting efficiency and optimizing blast design in large open-pit mines.

  4. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and air...

  5. Blast Injury

    PubMed Central

    de Candole, C. A.

    1967-01-01

    The shock wave generated by an explosion (“blast wave”) may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude. PMID:6015742

  6. Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

    NASA Astrophysics Data System (ADS)

    Feddema, Rick

    Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

  7. Aggregated Modeling and Control of Air Conditioning Loads for Demand Response

    SciTech Connect

    Zhang, Wei; Lian, Jianming; Chang, Chin-Yao; Kalsi, Karanjit

    2013-06-21

    Demand response is playing an increasingly important role in the efficient and reliable operation of the electric grid. Modeling the dynamic behavior of a large population of responsive loads is especially important to evaluate the effectiveness of various demand response strategies. In this paper, a highly-accurate aggregated model is developed for a population of air conditioning loads. The model effectively includes statistical information of the population, systematically deals with load heterogeneity, and accounts for second-order dynamics necessary to accurately capture the transient dynamics in the collective response. Based on the model, a novel aggregated control strategy is designed for the load population under realistic conditions. The proposed controller is fully responsive and achieves the control objective without sacrificing end-use performance. The proposed aggregated modeling and control strategies are validated through realistic simulations using GridLAB-D. Extensive simulation results indicate that the proposed approach can effectively manage a large number of air conditioning systems to provide various demand response services, such as frequency regulation and peak load reduction.

  8. Estimates of air emissions from asphalt storage tanks and truck loading

    SciTech Connect

    Trumbore, D.C.

    1999-12-31

    Title V of the 1990 Clean Air Act requires the accurate estimation of emissions from all US manufacturing processes, and places the burden of proof for that estimate on the process owner. This paper is published as a tool to assist in the estimation of air emission from hot asphalt storage tanks and asphalt truck loading operations. Data are presented on asphalt vapor pressure, vapor molecular weight, and the emission split between volatile organic compounds and particulate emissions that can be used with AP-42 calculation techniques to estimate air emissions from asphalt storage tanks and truck loading operations. Since current AP-42 techniques are not valid in asphalt tanks with active fume removal, a different technique for estimation of air emissions in those tanks, based on direct measurement of vapor space combustible gas content, is proposed. Likewise, since AP-42 does not address carbon monoxide or hydrogen sulfide emissions that are known to be present in asphalt operations, this paper proposes techniques for estimation of those emissions. Finally, data are presented on the effectiveness of fiber bed filters in reducing air emissions in asphalt operations.

  9. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., venting and air inlet devices. 179.200-16 Section 179.200-16 Transportation Other Regulations Relating to... and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air inlet... tank. Each tank or compartment may be equipped with one separate air connection. (b) When the...

  10. Minimisation of the explosion shock wave load onto the occupants inside the vehicle during trinitrotoluene charge blast.

    PubMed

    Krzystała, Edyta; Mężyk, Arkadiusz; Kciuk, Sławomir

    2016-01-01

    The aim of this study was to elaborate identification method of crew overload as a result of trinitrotoluene charge explosion under the military wheeled vehicle. During the study, an experimental military ground research was carried out. The aim of this research was to verify the mine blast resistance of the prototype wheeled vehicle according to STANG 4569 as well as the anti-explosive seat. Within the work, the original methodology was elaborated along with a prototype research statement. This article presents some results of the experimental research, thanks to which there is a possibility to estimate the crew's lives being endangered in an explosion through the measurement of acceleration as well as the pressure on the chest, head and internal organs. On the basis of our acceleration results, both effectiveness and infallibility of crew protective elements along with a blast mitigation seat were verified.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Comparative study on extinction process of gas-blasted air and CO2 arc discharge using two-dimensional electron density imaging sensor

    NASA Astrophysics Data System (ADS)

    Inada, Yuki; Kumada, Akiko; Ikeda, Hisatoshi; Hidaka, Kunihiko; Nakano, Tomoyuki; Murai, Kosuke; Tanaka, Yasunori; Shinkai, Takeshi

    2017-05-01

    Shack-Hartmann type laser wavefront sensors were applied to gas-blasted arc discharges under current-zero phases, generated in a 50 mm-long interelectrode gap confined by a gas flow nozzle, in order to conduct a systematic comparison of electron density decaying processes for two kinds of arc-quenching gas media: air and \\text{C}{{\\text{O}}2} . The experimental results for the air and \\text{C}{{\\text{O}}2} arc plasmas showed that the electron densities and arc diameters became thinner toward the nozzle-throat inlet due to a stronger convection loss in the arc radial direction. In addition, \\text{C}{{\\text{O}}2} had a shorter electron density decaying time constant than air, which could be caused by convection loss and turbulent flow of \\text{C}{{\\text{O}}2} stronger than air.

  13. Simulation of Blast Waves with Headwind

    NASA Technical Reports Server (NTRS)

    Olsen, Michael E.; Lawrence, Scott W.; Klopfer, Goetz H.; Mathias, Dovan; Onufer, Jeff T.

    2005-01-01

    The blast wave resulting from an explosion was simulated to provide guidance for models estimating risks for human spacecraft flight. Simulations included effects of headwind on blast propagation, Blasts were modelled as an initial value problem with a uniform high energy sphere expanding into an ambient field. Both still air and cases with headwind were calculated.

  14. Landing Characteristics of a Re-entry Vehicle with Canted Multiple Air Bag Load Alleviation System

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Investigation of the Landing Characteristics of a Re-entry Vehicle Having a Canted Multiple Air Bag Load Alleviation System. An investigation was made to determine the landing-impact characteristics of a reentry vehicle having a multiple-air-bag load-alleviation system. A 1/16-scale dynamic model having four canted air bags was tested at flight-path angles of 90 degrees (vertical), 45 degrees, and 27 degrees for a parachute or paraglider vertical letdown velocity of 30 feet per second (full scale). Landings were made on concrete at attitudes ranging from -l5 degrees to 20 degrees. The friction coefficient between the model heat shield and the concrete was approximately 0.4. An aluminum diaphragm, designed to rupture at 10.8 pounds per square inch gage, was used to maintain initial pressure in the air bags for a short time period. [Entire movie available on DVD from CASI as Doc ID 20070030986. Contact help@sti.nasa.gov

  15. Sulfur to nitrogen ratios in Ponderosa pine as bioindicators of foliar sulfur loading from air pollution

    SciTech Connect

    Johns, C.

    1984-01-01

    The objective of the research was to investigate the potential of foliar S:N ratios in Ponderosa pine as bioindicators of foliar sulfur loading in areas of long-term exposure to low levels of sulfurous air pollutants. First it was necessary to document seasonal variation in S:N ratios in trees not exposed to air pollution. Fifteen Ponderosa pines were selected at a site remote from urban and industrial sources of air pollution and the trees sampled at 18 intervals over a 15 month study period. Significant differences in sulfur and nitrogen concentrations occurred among the five needle age groups within most collections. One-year-old needles contained significantly more sulfur than other needles. Current-year needles contained more nitrogen than the three and four-year-old needles. Within each foliar age class significant differences in total sulfur content and S:N ratios occurred throughout the season. Sulfur concentrations and S:N r

  16. The effect of loading on disturbance sounds of the Atlantic croaker Micropogonius undulatus: Air versus water

    NASA Astrophysics Data System (ADS)

    Fine, Michael L.; Schrinel, Justin; Cameron, Timothy M.

    2004-08-01

    Physiological work on fish sound production may require exposure of the swimbladder to air, which will change its loading (radiation mass and resistance) and could affect parameters of emitted sounds. This issue was examined in Atlantic croaker Micropogonius chromis by recording sounds from the same individuals in air and water. Although sonograms appear relatively similar in both cases, pulse duration is longer because of decreased damping, and sharpness of tuning (Q factor) is higher in water. However, pulse repetition rate and dominant frequency are unaffected. With appropriate caution it is suggested that sounds recorded in air can provide a useful tool in understanding the function of various swimbladder adaptations and provide reasonable approximation of natural sounds. Further, they provide an avenue for experimentally manipulating the sonic system, which can reveal details of its function not available from intact fish underwater.

  17. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    PubMed

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  18. Blast Induced Liquefaction Potential and Transient Porewater Pressure Response of Saturated Sands.

    DTIC Science & Technology

    1985-10-15

    Induced Licuefaction , Dames 4 Moore/U.S. Air Force, Maidenhead, United Kingdom, September 17-19, pp. 57-64. Schaepermeier, Z., (1978b), " Soil Liquefaction...block number) GROUP SUB. GR. Liquefaction, Porewater Pressure, Dynamic Testing, Blast Loading, Soil Mechanics, Laboratory Testing, Material Model- -Al...long term porewater pressure response5;f saturated soils . The facility is capable of generatin compressive shock loadings on the order of 35000 KPa with

  19. Building Loads Analysis and System Thermodynamics (BLAST) Program Users Manual. Volume One. Supplement (Version 3.0).

    DTIC Science & Technology

    1981-03-01

    or the BLAST representative. 76 W1 Valid Day Types* HOLIDAY (HOL) SPECIALI (SPI) SPECIAL2 (SP2) SPECIAL3 (SP3) SPECIAL4 (S4 DAYLIGHT ( DST ): daylight...SPLCIALI - FROM I AUG THRU 15 AUG, DS1 z FROM LAST SUN IN APR THRU LAST SUN IN OCT, HOURLY = FROM LAST SUN IN APR THRU 5 MAY, Run Period For the run...TITLE TIT R UN YEAR YR LATITUDE LAI LONGITUDE LONG TIME ZONE TIME, TIM, TIME ZONES TAPE TAP DAYLIGHT DST HOLIDAY HOL SPLCIALI SPI SPECIAL? SP2 SPEC IAL3

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

    SciTech Connect

    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.

  1. Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

    NASA Technical Reports Server (NTRS)

    Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

    2008-01-01

    NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

  2. Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

    NASA Technical Reports Server (NTRS)

    Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

    2008-01-01

    NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

  3. A novel closed-body model of spinal cord injury caused by high-pressure air blasts produces extensive axonal injury and motor impairments

    PubMed Central

    del Mar, Nobel; von Buttlar, Xinyu; Yu, Angela S.; Guley, Natalie H.; Reiner, Anton; Honig, Marcia G.

    2015-01-01

    Diffuse axonal injury is thought to be the basis of the functional impairments stemming from mild traumatic brain injury. To examine how axons are damaged by traumatic events, such as motor vehicle accidents, falls, sports activities, or explosive blasts, we have taken advantage of the spinal cord with its extensive white matter tracts. We developed a closed-body model of spinal cord injury in mice whereby high-pressure air blasts targeted to lower thoracic vertebral levels produce tensile, compressive, and shear forces within the parenchyma of the spinal cord and thereby cause extensive axonal injury. Markers of cytoskeletal integrity showed that spinal cord axons exhibited three distinct pathologies: microtubule breakage, neurofilament compaction, and calpain-mediated spectrin breakdown. The dorsally situated axons of the corticospinal tract primarily exhibited microtubule breakage, whereas all three pathologies were common in the lateral and ventral white matter. Individual axons typically demonstrated only one of the three pathologies during the first 24 h after blast injury, suggesting that the different perturbations are initiated independently of one another. For the first few days after blast, neurofilament compaction was frequently accompanied by autophagy, and subsequent to that, by the fragmentation of degenerating axons. TuJ1 immunolabeling and mice with YFP-reporter labeling each revealed more extensive microtubule breakage than did βAPP immunolabeling, raising doubts about the sensitivity of this standard approach for assessing axonal injury. Although motor deficits were mild and largely transient, some aspects of motor function gradually worsened over several weeks, suggesting that a low level of axonal degeneration continued past the initial wave. Our model can help provide further insight into how to intervene in the processes by which initial axonal damage culminates in axonal degeneration, to improve outcomes after traumatic injury. Importantly

  4. Impacts of rising air temperatures on electric transmission ampacity and peak electricity load in the United States

    NASA Astrophysics Data System (ADS)

    Bartos, Matthew; Chester, Mikhail; Johnson, Nathan; Gorman, Brandon; Eisenberg, Daniel; Linkov, Igor; Bates, Matthew

    2016-11-01

    Climate change may constrain future electricity supply adequacy by reducing electric transmission capacity and increasing electricity demand. The carrying capacity of electric power cables decreases as ambient air temperatures rise; similarly, during the summer peak period, electricity loads typically increase with hotter air temperatures due to increased air conditioning usage. As atmospheric carbon concentrations increase, higher ambient air temperatures may strain power infrastructure by simultaneously reducing transmission capacity and increasing peak electricity load. We estimate the impacts of rising ambient air temperatures on electric transmission ampacity and peak per-capita electricity load for 121 planning areas in the United States using downscaled global climate model projections. Together, these planning areas account for roughly 80% of current peak summertime load. We estimate climate-attributable capacity reductions to transmission lines by constructing thermal models of representative conductors, then forcing these models with future temperature projections to determine the percent change in rated ampacity. Next, we assess the impact of climate change on electricity load by using historical relationships between ambient temperature and utility-scale summertime peak load to estimate the extent to which climate change will incur additional peak load increases. We find that by mid-century (2040-2060), increases in ambient air temperature may reduce average summertime transmission capacity by 1.9%-5.8% relative to the 1990-2010 reference period. At the same time, peak per-capita summertime loads may rise by 4.2%-15% on average due to increases in ambient air temperature. In the absence of energy efficiency gains, demand-side management programs and transmission infrastructure upgrades, these load increases have the potential to upset current assumptions about future electricity supply adequacy.

  5. Controlling a rabbet load and air/oil seal temperatures in a turbine

    DOEpatents

    Schmidt, Mark Christopher

    2002-01-01

    During a standard fired shutdown of a turbine, a loaded rabbet joint between the fourth stage wheel and the aft shaft of the machine can become unloaded causing a gap to occur due to a thermal mismatch at the rabbet joint with the bearing blower turned on. An open or unloaded rabbet could cause the parts to move relative to each other and therefore cause the rotor to lose balance. If the bearing blower is turned off during a shutdown, the forward air/oil seal temperature may exceed maximum design practice criterion due to "soak-back." An air/oil seal temperature above the established maximum design limits could cause a bearing fire to occur, with catastrophic consequences to the machine. By controlling the bearing blower according to an optimized blower profile, the rabbet load can be maintained, and the air/oil seal temperature can be maintained below the established limits. A blower profile is determined according to a thermodynamic model of the system.

  6. A piloted simulation investigation of the normal load factor and longitudinal thrust required for air-to-air acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Whalley, Matthew S.

    1993-01-01

    A piloted simulation study was performed by the U.S. Army Aeroflighydynamics Directorate to develop insight into the maneuverability requirements for aggressive helicopter maneuvering tasks such as air-to-air combat. Both a conventional helicopter and a helicopter with auxiliary thrust were examined. The aircraft parameters of interest were the normal and longitudinal load factor envelopes. Of particular interest were the mission performance and handling qualities tradeoffs with the parameters of interest. Two air-to-air acquisition and tracking tasks and a return-to-cover task were performed to assess mission performance. Results indicate that without auxiliary thrust, the ownship normal load factor capability needs to match that of the adversary in order to provide satisfactory handling qualities. Auxiliary thrust provides significant handling qualities advantages and can be substituted to some extent for normal load factor capability. Auxiliary thrust levels as low as 0.2 thrust/weight can provide significant handling qualities advantages.

  7. Understanding the Dehumidification Performance of Air-Conditioning Equipment at Part-Load Conditions

    SciTech Connect

    Don B. Shirey III; Hugh I. Henderson Jr; Richard A. Raustad

    2006-01-01

    Air conditioner cooling coils typically provide both sensible cooling and moisture removal. Data from a limited number of field studies (Khattar et al. 1985; Henderson and Rengarajan 1996; Henderson 1998) have demonstrated that the moisture removal capacity of a cooling coil degrades at part-load conditions--especially when the supply fan operates continuously while the cooling coil cycles on and off. Degradation occurs because moisture that condenses on the coil surfaces during the cooling cycle evaporates back into air stream when the coil is off. This degradation affects the ability of cooling equipment to maintain proper indoor humidity levels and may negatively impact indoor air quality. This report summarizes the results of a comprehensive project to better understand and quantify the moisture removal (dehumidification) performance of cooling coils at part-load conditions. A review of the open literature was initially conducted to learn from previous research on this topic. Detailed performance measurements were then collected for eight cooling coils in a controlled laboratory setting to understand the impact of coil geometry and operating conditions on transient moisture condensation and evaporation by the coils. Measurements of cooling coil dehumidification performance and space humidity levels were also collected at seven field test sites. Finally, an existing engineering model to predict dehumidification performance degradation for single-stage cooling equipment at part-load conditions (Henderson and Rengarajan 1996) was enhanced to include a broader range of fan control strategies and an improved theoretical basis for modeling off-cycle moisture evaporation from cooling coils. The improved model was validated with the laboratory measurements, and this report provides guidance for users regarding proper model inputs. The model is suitable for use in computerized calculation procedures such as hourly or sub-hourly building energy simulation programs (e

  8. Computer cast blast modelling

    SciTech Connect

    Chung, S.; McGill, M.; Preece, D.S.

    1994-07-01

    Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC, applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the DMC can perform a blast simulation in 0.5 hours on the SUN SPARCstation 10--41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC computer. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

  9. Numerical simulation of air-blast atomization of a liquid layer

    NASA Astrophysics Data System (ADS)

    Agbaglah, G. Gilou; McCaslin, Jeremy; Desjardins, Olivier

    2015-11-01

    Numerical simulations of a planar co-flowing air/water airblast atomization is performed using an in-house multiphase Navier-Stokes solver based on a semi-lagrangian geometric Volume of Fluid (VOF) method to track the position of the interface. This solver conserves mass and momentum exactly within each phase. Excellent agreement with recent experiments is obtained when comparing physical quantities, such as the liquid cone length, the maximum wave frequency and the spatial growth rate of the primary instability. A full three dimensional simulation is used to analyze the turbulence in the gas phase. The gas layer is laminar close to the injector and becomes turbulent at downstream positions. The transition to the turbulence is shown to increase first as an exponential function of the downstream positions and then reach a statistically stable regime where the liquid wave crests expand in a thin sheet which breaks into secondary droplets.

  10. Effect of Human and Sheep Lung Orientation on Primary Blast Injury Induced by Single Blast

    DTIC Science & Technology

    2010-09-01

    may be injured by m ore than one of these mechanisms in any given event. Primary blast in juries ( PBI ) are exclusively caused by the blast...overpressure. A PBI usually affects air-containing organs such as t he lung, ears and gastrointestinal tract. Secon dary blast injuries are caused by...orientation on blast injuries predicted in human and sheep models. From th is study, it is predicted that the greatest reduction in lung PBI may be

  11. Active control of spectral detail radiated by an air-loaded impacted membrane

    NASA Astrophysics Data System (ADS)

    Rollow, J. Douglas, IV

    An active control system is developed to independently operate on the vibration of individual modes of an air-loaded drum head, resulting in changes in the acoustic field radiated from the structure. The timbre of the system is investigated, and techniques for changing the characteristic frequencies by means of the control system are proposed. A feedforward control system is constructed for empirical investigation of this approach, creating a musical instrument which can produce a variety of sounds not available with strictly mechanical systems. The work is motivated by applications for actively controlled structures, active control of sound quality, and musical acoustics. The instrument consists of a Mylar timpano head stretched over an enclosure which has been outfitted with electroacoustic drivers. Sensors are arranged on the surface of the drum head and combined to measure modal vibration, and the array of drivers allows independent control of these modes. A signal processor is used to form modal control filters which can modify the loading of each mode, changing the time-dependent and spectral characteristics, and therefore the timbre, of the radiated sound. A theoretical formulation of active control of structural vibration by means of fluid-coupled actuators is expressed, and computational solutions show the effects of fluid loading and the radiated field. Experimental results with the new instrument are shown, with implementations of the control system providing a demonstrated degree of control, and illustrating several limitations of such systems.

  12. Risk Assessment of Heating, Ventilating, and Air-Conditioning Strategies in Low-Load Homes

    SciTech Connect

    Poerschke, Andrew

    2016-02-17

    "Modern, energy efficient homes conforming to the Zero Energy Ready Home standard face the challenge of meeting high customer expectations for comfort. Traditional heating, ventilation, and air conditioning (HVAC) sizing and control strategies may be insufficient to adequately condition each zone due to unique load patterns in each room caused by a number of factors. These factors include solar heat gains, occupant-related gains, and gains associated with appliances and electronics. Because of shrinking shell loads, these intermittent factors are having an increasingly significant impact on the thermal load in each zone. Consequently, occupant comfort can be compromised. To evaluate the impact of climate and house geometry, as well as HVAC system and control strategies on comfort conditions, IBACOS analyzed the results of 99 TRNSYS multiple-zone simulations. The results of this analysis indicate that for simple-geometry and single-story plans, a single zone and thermostat can adequately condition the entire house. Demanding house geometry and houses with multiple stories require the consideration of multiple thermostats and multiple zones.

  13. DIRECT COURSE blast shelter entranceway and blast door experiments

    SciTech Connect

    Kiger, S.A.; Hyde, D.W.

    1981-01-01

    The DIRECT COURSE Event is a high-explosive simulation of a 1-kt height-of-burst nuclear weapon. DIRECT COURSE is sponsored by the Defense Nuclear Agency and is scheduled for September 1983 at the White Sands Missile Range, New Mexico. Three entranceway experiments will be fielded, one full size complete with two blast doors to document structural response and loading in the simulated 1-kt blast environment. Also, two 1/10-scale models, one double and one single entrance configuration, will be used to obtain blast pressure data that can be scaled to a 1-Mt blast environment. Results from these experiments will be used to evaluate and improve structural response calculations for the 1-kt environment, and to obtain loading data for a 1-Mt environment. These data will be used to design entranceways and blast environment. Results from these experiments will be used to evaluate and improve structural response calculations for the 1-kt environment, and to obtain loading data for a 1-Mt environment. These data will be used to design entranceways and blast doors for the key worker blast shelter.

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

    SciTech Connect

    Price, Matthew A.

    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.

  15. A Single Point Pressure Approach As Input For Injury Models With Respect To Complex Blast Loading Conditions

    DTIC Science & Technology

    2010-10-01

    ANSYS AUTODYN 12.0 [8]. A subroutine was written implementing the Axelsson model (both BTD and SP) and the Modified Weathervane model in AUTODYN , thus...For the TNO SP model, the AUTODYN pressure history was exported to an Excel-file for processing. In all cases, the numerical simulations were run...grid. The standard air and TNT models from the AUTODYN material library were used. Thus, air was modelled as an ideal gas and the TNT was modelled

  16. Behavior and evaluation of an existing underground structure subjected to impulsive loads from an internal explosion

    SciTech Connect

    Keller, M.D.; Khan, P.K.

    1997-12-01

    An explosion is the result of a rapid chemical reaction which generates transient air pressure waves called blast waves. There has been much research on the processes of blast wave formation, propagation of blast waves, and quantification of the incident and reflected blast overpressures. The magnitude of blast overpressure, in a partially vented environment, is mainly a function of the type and quantity of detonating material, the amount of available venting, and the orientation and configuration of the reflecting surfaces. In addition to blast overpressure, an explosion can also generate high energy missiles (such as fragments), shock loads, and rapid rise of temperature in the confined space. This study concentrates on the effects of blast overpressure on a 40 feet diameter reinforced concrete cylinder with a hemispherical dome roof, supported on a 3 feet thick reinforced concrete pad, and buried under a minimum of 15 feet of soil used for radiation shielding at the top of the dome. The scope of this study is to determine whether the structure can withstand the blast overpressure generated by the postulated explosion without exceeding allowable design criteria.

  17. Blast Technologies

    DTIC Science & Technology

    2011-06-27

    Team Leader Risa Scherer Blast Mitigation Interior and Laboratory Team Leader Blast Technologies POC’s Government Point Of Contacts (POCs): To...to yield injury assessments at higher fidelities and with higher confidence UNCLASSIFIED UNCLASSIFIED Risa Scherer Blast Mitigation Interior and

  18. Effects of load voltage on voltage breakdown modes of electrical exploding aluminum wires in air

    SciTech Connect

    Wu, Jian; Li, Xingwen Yang, Zefeng; Wang, Kun; Chao, Youchuang; Shi, Zongqian; Jia, Shenli; Qiu, Aici

    2015-06-15

    The effects of the load voltage on the breakdown modes are investigated in exploding aluminum wires driven by a 1 kA, 0.1 kA/ns pulsed current in air. From laser probing images taken by laser shadowgraphy, schlieren imaging, and interferometry, the position of the shockwave front, the plasma channel, and the wire core edge of the exploding product can be determined. The breakdown mode makes a transition from the internal mode, which involves breakdown inside the wire core, to the shunting mode, which involves breakdown in the compressed air, with decreasing charging voltage. The breakdown electrical field for a gaseous aluminum wire core of nearly solid density is estimated to be more than 20 kV/cm, while the value for gaseous aluminum of approximately 0.2% solid density decreases to 15–20 kV/cm. The breakdown field in shunting mode is less than 20 kV/cm and is strongly affected by the vaporized aluminum, the desorbed gas, and the electrons emitted from the wire core during the current pause. Ohmic heating during voltage collapses will induce further energy deposition in the current channel and thus will result in different expansion speeds for both the wire core and the shockwave front in the different modes.

  19. Technical and economic assessment of fluidized-bed-augmented compressed-air energy-storage system: system load following capability

    SciTech Connect

    Lessard, R.D.; Blecher, W.A.; Merrick, D.

    1981-09-01

    The load-following capability of fluidized bed combustion-augmented compressed air energy storage systems was evaluated. The results are presented in two parts. The first part is an Executive Summary which provides a concise overview of all major elements of the study including the conclusions, and, second, a detailed technical report describing the part-load and load following capability of both the pressurized fluid bed combustor and the entire pressurized fluid bed combustor/compressed air energy storage system. The specific tasks in this investigation were to: define the steady-state, part-load operation of the CAES open-bed PFBC; estimate the steady-state, part-load performance of the PFBC/CAES system and evaluate any possible operational constraints; simulate the performance of the PFBC/CAES system during transient operation and assess the load following capability of the system; and establish a start-up procedure for the open-bed PFBC and evaluate the impact of this procedure. The conclusions are encouraging and indicate that the open-bed PFBC/CAES power plant should provide good part-load and transient performance, and should have no major equipment-related constraints, specifically, no major problems associated with the performance or design of either the open-end PFBC or the PFBC/CAES power plant in steady-state, part-load operation are envisioned. The open-bed PFBC/CAES power plant would have a load following capability which would be responsive to electric utility requirements for a peak-load power plant. The open-bed PFBC could be brought to full operating conditions within 15 min after routine shutdown, by employing a hot-start mode of operation. The PFBC/CAES system would be capable of rapid changes in output power (12% of design load per minute) over a wide output power range (25% to 100% of design output). (LCL)

  20. Landing Characteristics of a Reentry Capsule with a Torus-Shaped Air Bag for Load Alleviation

    NASA Technical Reports Server (NTRS)

    McGehee, John R.; Hathaway, Melvin E.

    1960-01-01

    An experimental investigation has been made to determine the landing characteristics of a conical-shaped reentry capsule by using torus-shaped air bags for impact-load alleviation. An impact bag was attached below the large end of the capsule to absorb initial impact loads and a second bag was attached around the canister to absorb loads resulting from impact on the canister when the capsule overturned. A 1/6-scale dynamic model of the configuration was tested for nominal flight paths of 60 deg. and 90 deg. (vertical), a range of contact attitudes from -25 deg. to 30 deg., and a vertical contact velocity of 12.25 feet per second. Accelerations were measured along the X-axis (roll) and Z-axis (yaw) by accelerometers rigidly installed at the center of gravity of the model. Actual flight path, contact attitudes, and motions were determined from high-speed motion pictures. Landings were made on concrete and on water. The peak accelerations along the X-axis for landings on concrete were in the order of 3Og for a 0 deg. contact attitude. A horizontal velocity of 7 feet per second, corresponding to a flight path of 60 deg., had very little effect upon the peak accelerations obtained for landings on concrete. For contact attitudes of -25 deg. and 30 deg. the peak accelerations along the Z-axis were about +/- l5g, respectively. The peak accelerations measured for the water landings were about one-third lower than the peak accelerations measured for the landings on concrete. Assuming a rigid body, computations were made by using Newton's second law of motion and the force-stroke characteristics of the air bag to determine accelerations for a flight path of 90 deg. (vertical) and a contact attitude of 0 deg. The computed and experimental peak accelerations and strokes at peak acceleration were in good agreement for the model. The special scaling appears to be applicable for predicting full-scale time and stroke at peak acceleration for a landing on concrete from a 90 deg

  1. Landing Characteristics of a Reentry Capsule with a Torus-Shaped Air Bag for Load Alleviation

    NASA Technical Reports Server (NTRS)

    McGehee, John R.; Hathaway, Melvin E.

    1960-01-01

    An experimental investigation has been made to determine the landing characteristics of a conical-shaped reentry capsule by using torus-shaped air bags for impact-load alleviation. An impact bag was attached below the large end of the capsule to absorb initial impact loads and a second bag was attached around the canister to absorb loads resulting from impact on the canister when the capsule overturned. A 1/6-scale dynamic model of the configuration was tested for nominal flight paths of 60 deg. and 90 deg. (vertical), a range of contact attitudes from -25 deg. to 30 deg., and a vertical contact velocity of 12.25 feet per second. Accelerations were measured along the X-axis (roll) and Z-axis (yaw) by accelerometers rigidly installed at the center of gravity of the model. Actual flight path, contact attitudes, and motions were determined from high-speed motion pictures. Landings were made on concrete and on water. The peak accelerations along the X-axis for landings on concrete were in the order of 3Og for a 0 deg. contact attitude. A horizontal velocity of 7 feet per second, corresponding to a flight path of 60 deg., had very little effect upon the peak accelerations obtained for landings on concrete. For contact attitudes of -25 deg. and 30 deg. the peak accelerations along the Z-axis were about +/- l5g, respectively. The peak accelerations measured for the water landings were about one-third lower than the peak accelerations measured for the landings on concrete. Assuming a rigid body, computations were made by using Newton's second law of motion and the force-stroke characteristics of the air bag to determine accelerations for a flight path of 90 deg. (vertical) and a contact attitude of 0 deg. The computed and experimental peak accelerations and strokes at peak acceleration were in good agreement for the model. The special scaling appears to be applicable for predicting full-scale time and stroke at peak acceleration for a landing on concrete from a 90 deg

  2. Task IV: Groundshock-Induced Hydrogeologic Response: Volume 2. Hydrologic Response of Deep Based Systems to Blast Loading

    DTIC Science & Technology

    1994-09-01

    Miscellaneous Paper GL-94-49 0 September 1994 US Army Corps of Engineers AD-A285 745 Waterways Experiment Illilllii lI Station Task IV: Groundshock...Hydraulic fracturing. 1. Kim, Kwang Jin, 1949- II. United States. Army. Corps of Engineers . Ill. U.S. Army Engineer Waterways Experiment Station. IV... Geotechnical Laboratory (U.S.) V. United States. Air Force. Ballistic Missile Office. VI. Title. VII. Title: Groundshock-induced hydrogeologic response. Vill

  3. Blast Quantification Using Hopkinson Pressure Bars.

    PubMed

    Clarke, Samuel D; Fay, Stephen D; Rigby, Samuel E; Tyas, Andrew; Warren, James A; Reay, Jonathan J; Fuller, Benjamin J; Gant, Matthew T A; Elgy, Ian D

    2016-07-05

    Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

  4. Antioxidant depletion, lipid peroxidation, and impairment of calcium transport induced by air-blast overpressure in rat lungs.

    PubMed

    Elsayed, N M; Tyurina, Y Y; Tyurin, V A; Menshikova, E V; Kisin, E R; Kagan, V E

    1996-01-01

    Exposure to blast overpressure, or the sudden rise in atmospheric pressure after explosive detonation, results in damage mainly of the gas-filled organs. In addition to the physical damage, in the lung, injury may proceed via a hemorrhage-dependent mechanism initiating oxidative stress and accumulation of lipid peroxidation products. Massive rupture of capillaries and red blood cells, release of hemoglobin, its oxidation to met-hemoglobin and degradation sets the stage for heme-catalyzed oxidations. The authors hypothesized that lipid hydroperoxides interact with met-hemoglobin in the lungs of exposed animals to produce ferryl-hemoglobin, an extremely potent oxidant that induces oxidative damage by depleting antioxidants and initiating peroxidation reactions. Oxidation-induced disturbance of Ca2+ homeostasis facilitates further amplification of the damage. To test this hypothesis, groups of anesthetized rats (6 rats/group) were exposed to blast at 3 peak pressures: low (61.2 kPa), medium (95.2 kPa), high (136 kPa). One group served as an unexposed control. Immediately after exposure, the rats were euthanized and the lungs were analyzed for biochemical parameters. Blast overpressure caused: (1) depletion of total and water-soluble pulmonary antioxidant reserves and individual antioxidants (ascorbate, vitamin E, GSH), (2) accumulation of lipid peroxidation products (conjugated dienes, TBARS), and (3) inhibition of ATP-dependent Ca2+ transport. The magnitude of these changes in the lungs was proportional to the peak blast overpressure. Inhibition of Ca2+ transport strongly correlated with both depletion of antioxidants and enhancement of lipid peroxidation. In model experiments, met-hemoglobin/H2O2 produced damage to Ca2+ transport in the lungs from control animals similar to that observed in the lungs from blast overpressure-exposed animals. Ascorbate, which is known to reduce ferryl-hemoglobin, protected against met-hemoglobin/H2O2-induced damage of Ca2+ transport

  5. Sensitivity analysis of air gap motion with respect to wind load and mooring system for semi-submersible platform design

    NASA Astrophysics Data System (ADS)

    Huo, Fa-li; Nie, Yan; Yang, De-qing; Dong, Gang; Cui, Jin

    2016-07-01

    A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuff work especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design.

  6. Sikorsky UH-60 (USA 82-23748 NASA-748) Air-loads research aircraft - Blackhawk helicopter with

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Sikorsky UH-60 (USA 82-23748 NASA-748) Air-loads research aircraft - Blackhawk helicopter with MUX-Bucket in flight Note: Used in publication in Flight Research at Ames; 57 Years of Development and Validation of Aeronautical Technology NASA SP-1998-3300 fig. 135

  7. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.200-16 Section 179.200-16 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF...

  8. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF...

  9. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.200-16 Section 179.200-16 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF...

  10. Interfacing Computer-Assisted Drafting and Design with the Building Loads Analysis and System Thermodynamics (BLAST) Program

    DTIC Science & Technology

    1992-10-01

    Engineers (HQUSACE), under Project 4A162784AT45, "Energy and Energy Systems": Work Unit EA-X52, "Application of Advanced Computer Technologies to...7 BEGIN INPUT; RUN CONTROL: NEW ZONES, NEW AIR SYSTEMS, PLANT, UNITS (IN=ENGLISH, OUT=ENGLISH); PROJECT="SAMPLE BTEXT RUN" LOCATION=CHANUTE ; DESIGN...34; NORTH AXIS=0.00; SOLAR DISTRIBUTION=-1; ZONE 1 "LEFT END UNIT "- ORIGIN:(0.00, 0.00, 0.00); NORTH AXIS=0.00; EXTERIOR WALLS : STARTING AT(0.00, 0.00

  11. The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2001-01-01

    Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

  12. In-situ rock strength determination for blasting purposes

    SciTech Connect

    Soni, D.K.; Jain, A.

    1994-12-31

    Compressive strength of rocks is often required by mining engineers and quarrying authorities for blasting operations. Uniaxial compressive strength of rocks can be predicted with reasonable accuracy with the help of point load strength tests which can be easily conducted at site by the field staff, simultaneously as the cores are recovered from drilling operations. A number of diametral point load tests and uniaxial compressive strength tests have been conducted on the specimens of different rock types under air dried, and saturated condition as well to study the effect of ground water saturation on strength. It has been observed that due to saturation uniaxial compressive strength and point load strength get reduced to a maximum of 32 and 29 percent respectively. It has also been observed that uniaxial strength is sixteen times the point load strength in air dried as well as saturated condition. However, this factor used for calculating uniaxial compressive strength may be reduced to a lower value for the safety of miners in field blasting operations.

  13. Building Comfort Analysis Using BLAST: A Case Study

    DTIC Science & Technology

    1991-09-01

    Thermodynamics (BLAST) computer program includes the ability to model comfort parameters in addition to evalu- ating building energy performance. This study...new feature of the Building Loads Analysis and Systems Thermodynamics (BLAST) computer program includes the ability to model comfort parameters in...Systems Thermodynamics (BLAST) computer program to examine a facility’s comfort parameters. BLAST is a comprehensive hour-by-hour simulation program

  14. 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.

    PubMed

    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.

  15. 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

    PubMed Central

    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. PMID:27603017

  16. Transient Load Following and Control Analysis of Advanced S-CO2 Power Conversion with Dry Air Cooling

    SciTech Connect

    Moisseytsev, Anton; Sienicki, James J.

    2016-01-01

    Supercritical carbon dioxide (S-CO2) Brayton cycles are under development as advanced energy converters for advanced nuclear reactors, especially the Sodium-Cooled Fast Reactor (SFR). The use of dry air cooling for direct heat rejection to the atmosphere ultimate heat sink is increasingly becoming a requirement in many regions due to restrictions on water use. The transient load following and control behavior of an SFR with an S-CO2 cycle power converter utilizing dry air cooling have been investigated. With extension and adjustment of the previously existing control strategy for direct water cooling, S-CO2 cycle power converters can also be used for load following operation in regions where dry air cooling is a requirement

  17. Air-Loads Prediction of a UH-60A Rotor inside the 40- by 80-Foot Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Chang, I-Chung; Romander, Ethan A.; Potsdam, Mark; Yeo, Hyeonsoo

    2010-01-01

    The presented research extends the capability of a loose coupling computational fluid dynamics (CFD) and computational structure dynamics (CSD) code to calculate the flow-field around a rotor and test stand mounted inside a wind tunnel. Comparison of predicted air-load results for a full-scale UH-60A rotor recently tested inside the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel at Ames Research Center and in free-air flight are made for three challenging flight data points from the earlier conducted UH-60A Air-loads Program. Overall results show that the extension of the coupled CFD/CSD code to the wind-tunnel environment is generally successful.

  18. High-efficiency particulate air filter test stand and aerosol generator for particle loading studies.

    PubMed

    Arunkumar, R; Hogancamp, Kristina U; Parsons, Michael S; Rogers, Donna M; Norton, Olin P; Nagel, Brian A; Alderman, Steven L; Waggoner, Charles A

    2007-08-01

    This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30 x 30 x 29 cm(3) nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5 to 12 standard m(3)/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150 degrees C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7 standard m(3)/min, high mass concentrations (approximately 25 mg/m(3)) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160 nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions.

  19. Air-to-Water Heat Pumps With Radiant Delivery in Low-Load Homes

    SciTech Connect

    Backman, C.; German, A.; Dakin, B.; Springer, D.

    2013-12-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  20. Air-to-Water Heat Pumps With Radiant Delivery in Low-Load Homes

    SciTech Connect

    Backman, C.; German, A.; Dakin, B.; Springer, D.

    2013-12-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  1. Structural Optimization for Blast Mitigation Using HCA

    DTIC Science & Technology

    2009-08-14

    parameters for energy absorption AlonBrill,
Boaz
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Paul
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 LS ...function in Ls - Dyna , is an implementation of the hemispherical blast models of Kingery and Bulmash. •  Empirical blast -loading model rather than... DYNA 
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 Introduction: Design For Blast Mitigation UNCLASSIFIED
 •  Injury criteria of vehicle occupants due to mechanical input

  2. An investigation of the loads on the vertical tail of a jet-bomber airplane resulting from flight through rough air

    NASA Technical Reports Server (NTRS)

    Funk, Jack; Rhyne, Richard H

    1956-01-01

    Vertical-tail loads were measured in turbulent air on a four-engine jet bomber. Results showed large load oscillations which were lightly damped. Comparison of experimental results with discrete-load calculations indicated that discrete-gust calculations underestimated the loads by 30 to 40 percent and gave no indication of the low damping. Power spectral analysis, on the other hand, indicated the general frequency characteristics and gave a somewhat better estimate of the peak-load distributions. The present results strongly suggest that discrete-gust calculation for gust loads on vertical tails may seriously underestimate the gust loads for airplanes having lightly damped lateral oscillations.

  3. Mitigation of self-excited oscillations at full load: CFD analysis of air admission and effects of runner design

    NASA Astrophysics Data System (ADS)

    Chirkov, D.; Scherbakov, P.; Cherny, S.; Zakharov, A.; Skorospelov, V.; Turuk, P.

    2016-11-01

    In full and over load operating points some Francis turbines experience strong selfexcited pressure and power oscillations, which restrict the range of operation and maximum output of the turbine. Previously the authors proposed a 1D-3D two-phase model and numerical method for investigation of this phenomenon. In the present paper this model is further extended and applied to investigation of countermeasures, used for prevention of high load oscillations. First, the third phase - non-condensable air - is introduced into the model in order to investigate the effect of air admission. Then, several modifications of runner cone are examined, showing negligible effect on the amplitude and frequency of full load oscillations. Next, different modifications of runner blade shape are considered, giving different axial and circumferential velocity profiles downstream the runner. It is shown that variation of blade shape significantly affects the onset and intensity of self-excited oscillations. The obtained results indicate that proper runner design is able to eliminate high load instability without the need of air admission and reduction in turbine efficiency.

  4. Studies of air traffic forecasts, airspace load and the effect of ADS-B via satellites on flight times

    NASA Astrophysics Data System (ADS)

    Zhong, Z. W.; Ridhwan Salleh, Saiful; Chow, W. X.; Ong, Z. M.

    2016-10-01

    Air traffic forecasting is important as it helps stakeholders to plan their budgets and facilities. Thus, three most commonly used forecasting models were compared to see which model suited the air passenger traffic the best. General forecasting equations were also created to forecast the passenger traffic. The equations could forecast around 6.0% growth from 2015 onwards. Another study sought to provide an initial work for determining a theoretical airspace load with relevant calculations. The air traffic was simulated to investigate the current airspace load. Logical and reasonable results were obtained from the modelling and simulations. The current utilization percentages for airspace load per hour and the static airspace load in the interested airspace were found to be 6.64% and 11.21% respectively. Our research also studied how ADS-B would affect the time taken for aircraft to travel. 6000 flights departing from and landing at the airport were studied. New flight plans were simulated with improved flight paths due to the implementation of ADS-B, and flight times of all studied flights could be improved.

  5. Effect of air-blast drying and the presence of protectants on the viability of yeast entrapped in calcium alginate beads with an aim to improve the survival rate.

    PubMed

    Kim, Dong-Hwan; Lee, Sae-Byuk; Park, Heui-Dong

    2017-01-01

    Five yeast strains, Saccharomyces cerevisiae D8, M12, and S13; Hanseniaspora uvarum S6; and Issatchenkia orientalis KMBL5774, isolated from Korean grapes, were entrapped in Ca-alginate beads, which are non-toxic, simple to use, and economical. Ca-alginate beads containing yeast cells were soaked in protective solutions, such as skim milk, saccharides, polyols, and nitrogen compounds, before air-blast drying to improve the yeast survival rate and storage ability. The results showed that both entrapment in Ca-alginate beads and soaking in protective agents favorably affected the survival of all strains. The microenvironment formed by the beads and protective agents can protect the yeast cells from harsh environmental conditions, such as low water (below 10 %). All the yeast strains entrapped in Ca-alginate beads showed greater than 80 % survival and less than 11 % water content after air-blast drying at 37 °C for 5 h. In addition, air-blast dried cells of S. cerevisiae D8, M12, S13; H. uvarum S6; and I. orientalis KMBL5774 entrapped in 2 % Ca-alginate beads and soaked in protective agents (10 % skim milk containing 10 % sucrose, 10 % raffinose, 10 % trehalose, 10 % trehalose, and 10 % glucose, respectively) after air-blast drying at 37 °C for 5 h showed 90, 87, 92, 90, and 87 % viability, respectively. All dried entrapped yeast cells showed survival rates of at least 51 % after storage at 4 °C for 3 months.

  6. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... holes, possible breakthrough, and water. Ammonium nitrate blasting agents shall not be loaded into wet... explosives shall be used only as primers with ammonium nitrate-fuel oil blasting agents. Such primers...

  7. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... holes, possible breakthrough, and water. Ammonium nitrate blasting agents shall not be loaded into wet... explosives shall be used only as primers with ammonium nitrate-fuel oil blasting agents. Such primers...

  8. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... holes, possible breakthrough, and water. Ammonium nitrate blasting agents shall not be loaded into wet... explosives shall be used only as primers with ammonium nitrate-fuel oil blasting agents. Such primers...

  9. Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

    SciTech Connect

    Gupta, A.; Biswas, P. ); Monson, P.R. ); Novick, V.J. )

    1993-07-01

    The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K[sub 2] was computed for different test conditions and used as a measure of the mass loading capacity. K[sub 2] was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K[sub 2] for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs.

  10. NREL's Energy-Saving Technology for Air Conditioning Cuts Peak Power Loads Without Using Harmful Refrigerants (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This fact sheet describes how the DEVAP air conditioner was invented, explains how the technology works, and why it won an R&D 100 Award. Desiccant-enhanced evaporative (DEVAP) air-conditioning will provide superior comfort for commercial buildings in any climate at a small fraction of the electricity costs of conventional air-conditioning equipment, releasing far less carbon dioxide and cutting costly peak electrical demand by an estimated 80%. Air conditioning currently consumes about 15% of the electricity generated in the United States and is a major contributor to peak electrical demand on hot summer days, which can lead to escalating power costs, brownouts, and rolling blackouts. DEVAP employs an innovative combination of air-cooling technologies to reduce energy use by up to 81%. DEVAP also shifts most of the energy needs to thermal energy sources, reducing annual electricity use by up to 90%. In doing so, DEVAP is estimated to cut peak electrical demand by nearly 80% in all climates. Widespread use of this cooling cycle would dramatically cut peak electrical loads throughout the country, saving billions of dollars in investments and operating costs for our nation's electrical utilities. Water is already used as a refrigerant in evaporative coolers, a common and widely used energy-saving technology for arid regions. The technology cools incoming hot, dry air by evaporating water into it. The energy absorbed by the water as it evaporates, known as the latent heat of vaporization, cools the air while humidifying it. However, evaporative coolers only function when the air is dry, and they deliver humid air that can lower the comfort level for building occupants. And even many dry climates like Phoenix, Arizona, have a humid season when evaporative cooling won't work well. DEVAP extends the applicability of evaporative cooling by first using a liquid desiccant-a water-absorbing material-to dry the air. The dry air is then passed to an indirect evaporative

  11. Human Injury Criteria for Underwater Blasts

    PubMed Central

    Lance, Rachel M.; Capehart, Bruce; Kadro, Omar; Bass, Cameron R.

    2015-01-01

    Underwater blasts propagate further and injure more readily than equivalent air blasts. Development of effective personal protection and countermeasures, however, requires knowledge of the currently unknown human tolerance to underwater blast. Current guidelines for prevention of underwater blast injury are not based on any organized injury risk assessment, human data or experimental data. The goal of this study was to derive injury risk assessments for underwater blast using well-characterized human underwater blast exposures in the open literature. The human injury dataset was compiled using 34 case reports on underwater blast exposure to 475 personnel, dating as early as 1916. Using severity ratings, computational reconstructions of the blasts, and survival information from a final set of 262 human exposures, injury risk models were developed for both injury severity and risk of fatality as functions of blast impulse and blast peak overpressure. Based on these human data, we found that the 50% risk of fatality from underwater blast occurred at 302±16 kPa-ms impulse. Conservatively, there is a 20% risk of pulmonary injury at a kilometer from a 20 kg charge. From a clinical point of view, this new injury risk model emphasizes the large distances possible for potential pulmonary and gut injuries in water compared with air. This risk value is the first impulse-based fatality risk calculated from human data. The large-scale inconsistency between the blast exposures in the case reports and the guidelines available in the literature prior to this study further underscored the need for this new guideline derived from the unique dataset of actual injuries in this study. PMID:26606655

  12. Enhanced transverse load sensitivity by using a highly birefringent photonic crystal fiber with larger air holes on one axis.

    PubMed

    Kim, Hyun-Min; Kim, Tae-Hun; Kim, Bongkyun; Chung, Youngjoo

    2010-07-10

    We report on a transverse load sensor with enhanced sensitivity through the use of a birefringent interferometer based on a highly birefringent photonic crystal fiber (HB-PCF). The transverse load sensitivity can be enhanced by using a fabricated HB-PCF having larger air holes on its fast axis. The transverse load sensitivity was measured to be high: approximately 2.17 nm/(N/cm). The temperature-induced undesirable effects can be ignored because transmission outputs of our HB-PCF were stable with the change of the temperature. The sensing probe can be compact because of its high birefringence with the order of 10(-3) and no bending loss.

  13. Evaluation of Ag nanoparticle coated air filter against aerosolized virus: Anti-viral efficiency with dust loading.

    PubMed

    Joe, Yun Haeng; Park, Dae Hoon; Hwang, Jungho

    2016-01-15

    In this study, the effect of dust loading on the anti-viral ability of an anti-viral air filter was investigated. Silver nanoparticles approximately 11 nm in diameter were synthesized via a spark discharge generation system and were used as anti-viral agents coated onto a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter against aerosolized bacteriophage MS2 virus particles were tested with dust loading. The filtration efficiency and pressure drop increased with dust loading, while the anti-viral ability decreased. Theoretical analysis of anti-viral ability with dust loading was carried out using a mathematical model based on that presented by Joe et al. (J. Hazard. Mater.; 280: 356-363, 2014). Our model can be used to compare anti-viral abilities of various anti-viral agents, determine appropriate coating areal density of anti-viral agent on a filter, and predict the life cycle of an anti-viral filter. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  15. High bacterial load of indoor air in hospital wards: the case of University of Gondar teaching hospital, Northwest Ethiopia.

    PubMed

    Gizaw, Zemichael; Gebrehiwot, Mulat; Yenew, Chalachew

    2016-01-01

    The air inhaled by people is abundantly populated with microorganisms which also are called bioaerosols. Bioaerosols is a colloidal suspension, formed by liquid droplets and particles of solid matter in the air, whose components contain or have attached to them viruses, fungal spores and conidia, bacterial endospores, plant pollen and fragments of plant tissues. They account for 5-34 % of indoor air pollution. A cross-sectional study was conducted to assess the bacteriological concentration and to identify specific species of bacteria in the indoor air of Gondar University teaching hospital. Air samples were taken from 14 randomly selected wards. Bacterial measurements were made by passive air sampling technique i.e., the settle plate method. In each ward five Petri dishes were exposed for 30 and 60 min in the morning and afternoon. Bacteria were collected on nutrient agar and blood agar media. Both quantitative and qualitative analyses were conducted. The quantitative analysis was mainly conducted to determine bacterial load or number of bacteria in the indoor air. Bacterial load was enumerated as colony forming units. Qualitative analysis was conducted to identify specific species of bacteria. For this study we have selected Staphylococcus aureus and Streptococcus which had high public health concern. Mannitol test was used to isolate Staphylococcus aureus, whereas Bacitracin test was conducted to isolate Streptococcus pyogene. The result of this study indicated that the highest bacterial load which was 1468 CFU/m(3) has been recorded at 2:00 PM in Ward C at 60 min exposure time and the lowest bacterial concentration (i.e., 480 CFU/m(3)) was recorded at 8:00 AM in physiotherapy ward. Based on the result bacterial concentration of indoor air of Gondar University teaching hospital was found between 480 and 1468 CFU/m(3). The result of one way ANOVA showed that the highest mean bacterial concentration (1271.00 CFU/m(3)) was found in Medical ward and the

  16. BLAST: a more efficient report with usability improvements

    PubMed Central

    Boratyn, Grzegorz M.; Camacho, Christiam; Cooper, Peter S.; Coulouris, George; Fong, Amelia; Ma, Ning; Madden, Thomas L.; Matten, Wayne T.; McGinnis, Scott D.; Merezhuk, Yuri; Raytselis, Yan; Sayers, Eric W.; Tao, Tao; Ye, Jian; Zaretskaya, Irena

    2013-01-01

    The Basic Local Alignment Search Tool (BLAST) website at the National Center for Biotechnology (NCBI) is an important resource for searching and aligning sequences. A new BLAST report allows faster loading of alignments, adds navigation aids, allows easy downloading of subject sequences and reports and has improved usability. Here, we describe these improvements to the BLAST report, discuss design decisions, describe other improvements to the search page and database documentation and outline plans for future development. The NCBI BLAST URL is http://blast.ncbi.nlm.nih.gov. PMID:23609542

  17. BLAST: a more efficient report with usability improvements.

    PubMed

    Boratyn, Grzegorz M; Camacho, Christiam; Cooper, Peter S; Coulouris, George; Fong, Amelia; Ma, Ning; Madden, Thomas L; Matten, Wayne T; McGinnis, Scott D; Merezhuk, Yuri; Raytselis, Yan; Sayers, Eric W; Tao, Tao; Ye, Jian; Zaretskaya, Irena

    2013-07-01

    The Basic Local Alignment Search Tool (BLAST) website at the National Center for Biotechnology (NCBI) is an important resource for searching and aligning sequences. A new BLAST report allows faster loading of alignments, adds navigation aids, allows easy downloading of subject sequences and reports and has improved usability. Here, we describe these improvements to the BLAST report, discuss design decisions, describe other improvements to the search page and database documentation and outline plans for future development. The NCBI BLAST URL is http://blast.ncbi.nlm.nih.gov.

  18. Blasting response of the Eiffel Tower

    NASA Astrophysics Data System (ADS)

    Horlyck, Lachlan; Hayes, Kieran; Caetano, Ryan; Tahmasebinia, Faham; Ansourian, Peter; Alonso-Marroquin, Fernando

    2016-08-01

    A finite element model of the Eiffel Tower was constructed using Strand7 software. The model replicates the existing tower, with dimensions justified through the use of original design drawings. A static and dynamic analysis was conducted to determine the actions of the tower under permanent, imposed and wind loadings, as well as under blast pressure loads and earthquake loads due to an explosion. It was observed that the tower utilises the full axial capacity of individual members by acting as a `truss of trusses'. As such, permanent and imposed loads are efficiently transferred to the primary columns through compression, while wind loads induce tensile forces in the windward legs and compressive forces in the leeward. Under blast loading, the tower experienced both ground vibrations and blast pressures. Ground vibrations induced a negligibly small earthquake loading into the structure which was ignored in subsequent analyses. The blast pressure was significant, and a dynamic analysis of this revealed that further research is required into the damping qualities of the structure due to soil and mechanical properties. In the worst case scenario, the blast was assumed to completely destroy several members in the adjacent leg. Despite this weakened condition, it was observed that the tower would still be able to sustain static loads, at least for enough time for occupant evacuation. Further, an optimised design revealed the structure was structurally sound under a 46% reduction of the metal tower's mass.

  19. Survival and growth of micro-organisms on air filtration media during initial loading

    NASA Astrophysics Data System (ADS)

    Kemp, P. C.; Neumeister-Kemp, H. G.; Lysek, G.; Murray, F.

    A new type of air filtration medium made from a hygroscopic polymer fibre and constructed in three layers was investigated to measure the survival and growth of micro-organisms on this medium in comparison to a widely used fibreglass medium. Both materials were supplied by the manufacturer and tested "blind". The materials were loaded in an Airotester unit. Micro-organisms were analysed at 2 weekly intervals for 8 weeks by washing filter samples and plating the solution on to agar media and by vital fluorescence microscopy. Filter samples were also weighed to calculate water content and the pH value of the filter material was measured in the wash out eluate. Vital fluorescence microscopy revealed fungi were able to grow on fibreglass medium, but not on the multi-layered polymer. The colony forming unit (CFU) counts did not increase at a steady rate. There was a significant increase on both materials ( P<0.001) during the first 2 weeks which was then followed by a significant decrease in 4 weeks ( P<0.001) but the CFU then significantly increased in 6 weeks ( P<0.05) which were the highest CFU counts during the 2-month trial. There was a significant difference in CFU counts between the filter materials only in week 2 ( P⩽0.001) and week 4 ( P=0.04). Fewer micro-organisms were extracted from the multi-layered polymer than from the fibreglass medium. Fewer fungal species were identified on the multi-layered polymer (nine species) than on the fibreglass medium (13 species). The pH value on the multi-layered polymer was significantly higher than the fibreglass material but only when clean ( P<0.010) and after 2 weeks ( P<0.001). A significantly higher water content on the fibreglass medium ( P<0.001) also indicated a habitat where a wider range of fungal species and bacteria are able to survive. While there was a reduced survival and growth of micro-organisms on the multi-layered polymer material in the initial month of service life, this advantage was cancelled by

  20. Calculating the parameters of self-oscillations in the vertical combustion chamber of the blast-furnace air heater during unstable combustion

    NASA Astrophysics Data System (ADS)

    Basok, B. I.; Gotsulenko, V. V.

    2015-01-01

    A procedure for simplified calculation of the parameters of self-oscillations excited during unstable (vibrating) combustion in the vertical combustion chambers of blast-furnace air heaters is developed. The proposed procedure is based on an independent nonlinear dynamic system similar to the equations from the theory of a blade supercharger stalling and surging mode. The head characteristic considered in the blade supercharger stalling and surging theory determines the part of the supercharger drive rotation energy that is converted into the head developed by the supercharger. In the considered system, the supercharger head characteristic is replaced by the combustion chamber head characteristic. Being a function of flow rate, this characteristic describes the part of heat supplied to flow that is converted to the flow head. Unlike the supercharger head characteristic, which is determined by experiment, the combustion chamber head characteristic is determined by calculation, due to which it becomes much easier to calculate the parameters of self-oscillations according to the proposed procedure. In particular, an analysis of the periodic solutions of the obtained dynamic system made it possible to determine the pattern in which the amplitude of considered self-oscillations depends on the surge impedance of the vertical combustion chamber.

  1. Approach to the CFD analysis applied to HMDs during high-speed wind blast

    NASA Astrophysics Data System (ADS)

    Tiu, William; Ingleton, Martin

    2000-06-01

    Helmet Mounted Displays (HMD) are now an essential element in fast jet aircraft cockpits and the demanding safety requirements must be maintained. Exposure to high-speed air- blast was a fundamental requirement of a developmental HMD produced by BAE SYSTEMS. Safety criteria based on stability, strength and aerodynamic loads meant that reliance on an empirical development was no longer appropriate. Success was achieved from a combination of experience, analysis, design and testing. Computational Fluid Dynamics modeling combined with validation testing in a wind tunnel provided a vital understanding of the aerodynamic loads developed during the windblast event and significantly reduced developmental risk.

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

    NASA Astrophysics Data System (ADS)

    Singh, D.; Cronin, D. S.

    2017-06-01

    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.

  3. Soil Behavior Under Blast Loading

    DTIC Science & Technology

    2010-12-01

    3.62) ( ) HHH VV P EE −=− 00 2 ...........................................................................................(3.63) where...as HHH EV V EVP )( )( γ ργ == ........................................................................................(3.77) If the Hugoniot is the

  4. Numerical Simulation for Blast Analysis of Insulating Glass in a Curtain Wall

    NASA Astrophysics Data System (ADS)

    Deng, Rong-bing; Jin, Xian-long

    2010-04-01

    This article presents a three-dimensional numerical simulation method for blast response calculation of insulating glass in a curtain wall based on multi-material arbitrary Lagrangian-Eulerian (ALE) formulation and high-performance computer. The whole analytical model consists of explosion, air, curtain wall system, and ground. In particular, detailed components including insulating glass panels, aluminum column, silicone sealant, and other parts in the curtain wall are set up in terms of actual size and actual assembly. This model takes account of the coupling between blast and structure, nonlinear material behavior, brittle failure of glass material, and non-reflecting boundary definition. Final calculation has been performed on the Dawning 4000A supercomputer using the finite-element code LS-DYNA 971 MPP. The propagation of shock wave in air and blast-structure interaction is quite well estimated by numerical calculation. The damage regions of outer and inner glass are reproduced in the numerical simulations, which are in agreement with the experimental observations. The result provides a global understanding of insulating glass panels under blast loading in the curtain wall system. It may be generated to supplement experimental studies for developing appropriate design guidelines for curtain wall systems as well.

  5. Characterization of Viral Load, Viability and Persistence of Influenza A Virus in Air and on Surfaces of Swine Production Facilities

    PubMed Central

    Neira, Victor; Rabinowitz, Peter; Rendahl, Aaron; Paccha, Blanca; Gibbs, Shawn G.; Torremorell, Montserrat

    2016-01-01

    Indirect transmission of influenza A virus (IAV) in swine is poorly understood and information is lacking on levels of environmental exposure encountered by swine and people during outbreaks of IAV in swine barns. We characterized viral load, viability and persistence of IAV in air and on surfaces during outbreaks in swine barns. IAV was detected in pigs, air and surfaces from five confirmed outbreaks with 48% (47/98) of oral fluid, 38% (32/84) of pen railing and 43% (35/82) of indoor air samples testing positive by IAV RT-PCR. IAV was isolated from air and oral fluids yielding a mixture of subtypes (H1N1, H1N2 and H3N2). Detection of IAV RNA from air was sustained during the outbreaks with maximum levels estimated between 7 and 11 days from reported onset. Our results indicate that during outbreaks of IAV in swine, aerosols and surfaces in barns contain significant levels of IAV potentially representing an exposure hazard to both swine and people. PMID:26757362

  6. Main rotor free wake geometry effects on blade air loads and response for helicopters in steady maneuvers. Volume 1: Theoretical formulation and analysis of results

    NASA Technical Reports Server (NTRS)

    Sadler, S. G.

    1972-01-01

    A mathematical model and computer program were implemented to study the main rotor free wake geometry effects on helicopter rotor blade air loads and response in steady maneuvers. The theoretical formulation and analysis of results are presented.

  7. Abdominal trauma in primary blast injury.

    PubMed

    Owers, C; Morgan, J L; Garner, J P

    2011-02-01

    Blast injury is uncommon, and remains poorly understood by most clinicians outside regions of active warfare. Primary blast injury (PBI) results from the interaction of the blast wave with the body, and typically affects gas-containing organs such as the ear, lungs and gastrointestinal tract. This review investigates the mechanisms and injuries sustained to the abdomen following blast exposure. MEDLINE was searched using the keywords 'primary blast injury', 'abdominal blast' and 'abdominal blast injury' to identify English language reports of abdominal PBI. Clinical reports providing sufficient data were used to calculate the incidence of abdominal PBI in hospitalized survivors of air blast, and in open- and enclosed-space detonations. Sixty-one articles were identified that primarily reported clinical or experimental abdominal PBI. Nine clinical reports provided sufficient data to calculate an incidence of abdominal PBI; 31 (3·0 per cent) of 1040 hospitalized survivors of air blast suffered abdominal PBI, the incidence ranging from 1·3 to 33 per cent. The incidence for open- and enclosed-space detonations was 5·6 and 6·7 per cent respectively. The terminal ileum and caecum were the most commonly affected organs. Surgical management of abdominal PBI is similar to that of abdominal trauma of other causes. Abdominal PBI is uncommon but has the potential for significant mortality and morbidity, which may present many days after blast exposure. It is commoner after blast in enclosed spaces and under water. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

  8. Influence of hydraulic loading and air flowrate on urban wastewater nitrogen removal with a submerged fixed-film reactor.

    PubMed

    Gálvez, J M; Gómez, M A; Hontoria, E; González-López, J

    2003-07-18

    Nutrient disposal to sensitive areas, particularly nitrogen and phosphorus from wastewater treatment plants, provokes eutrophication reducing water quality. Fixed film technology is widely used for the removal of organic matter and nitrogen by the biological process of nitrification-denitrification. This paper studies a nitrification and post-denitrification lab-scale plant with a downflow aerobic submerged filter for removal of organic matter and nitrification, followed by an anoxic upflow biofilter for denitrification. Recycled construction material (clay shists) was employed as support material and methanol was used as carbon source. After 2 weeks of acclimation in which nitrification reached steady-state conditions, different hydraulic loadings (0.35-1.59 m(3)/m(2)h) and air flowrates (7.78-43.5 m(3)/m(2)h) were applied for 1 year. The highest hydraulic loading which complied with the EU regulation on nitrogen disposal was 0.71 m(3)/m(2)h (1.6 h). Hydraulic retention time (HRT), which corresponded to a nitrogen removal of 0.64 kg N/m(3) per day operating at an air flowrate of 25.6 m(3)/m(2)h. Concerning to organic matter removal efficiency, the aerobic reactor accepted a maximum chemical oxygen demand (COD) volumetric loading of 16.0 kg COD/m(3) per day with a 75% COD removal efficiency. For all the tests carried out, suspended solids (SS) concentration in the outlet water was less than 35 mg/l.

  9. [The influence of afferent inputs from the foot load receptors onto spinal alpha-motoneurons excitability in air-stepping condition].

    PubMed

    Selionov, V A; Solopova, I A

    2011-01-01

    We investigated excitability of alpha-motoneurons during voluntary and passive locomotor-like movements under air-stepping conditions during the imitation of foot loading. Limb loading notably inhibited the H-reflex during both static condition and active or passive stepping. Thus, load-related afferent inputs play an essentially role in phase-dependence H-reflex modulation. The excitability of alpha-motoneurons in the most degree is influenced by afferent inflow from foot receptors.

  10. Mechanics of Air-Inflated Drop-Stitch Fabric Panels Subject to Bending Loads

    DTIC Science & Technology

    2013-08-15

    materials such as textiles , elastomers, and flexible composites are used for the structure, significant load-carrying capacity per unit weight (or...Drop-Stitch Fabrics Finite Element Analysis Experimental Mechanics Technical Textiles 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...27 LIST OF ILLUSTRATIONS Figure Page 1 Example of a Drop-Stitch Fabric with Rubber- Laminated

  11. Material Systems for Blast-Energy Dissipation

    SciTech Connect

    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.

  12. Experimental characterization and multidisciplinary conceptual design optimization of a bendable load stiffened unmanned air vehicle wing

    NASA Astrophysics Data System (ADS)

    Jagdale, Vijay Narayan

    Demand for deployable MAVs and UAVs with wings designed to reduce aircraft storage volume led to the development of a bendable wing concept at the University of Florida (UF). The wing shows an ability to load stiffen in the flight load direction, still remaining compliant in the opposite direction, enabling UAV storage inside smaller packing volumes. From the design prospective, when the wing shape parameters are treated as design variables, the performance requirements : high aerodynamic efficiency, structural stability under aggressive flight loads and desired compliant nature to prevent breaking while stored, in general conflict with each other. Creep deformation induced by long term storage and its effect on the wing flight characteristics are additional considerations. Experimental characterization of candidate bendable UAV wings is performed in order to demonstrate and understand aerodynamic and structural behavior of the bendable load stiffened wing under flight loads and while the wings are stored inside a canister for long duration, in the process identifying some important wing shape parameters. A multidisciplinary, multiobjective design optimization approach is utilized for conceptual design of a 24 inch span and 7 inch root chord bendable wing. Aerodynamic performance of the wing is studied using an extended vortex lattice method based Athena Vortex Lattice (AVL) program. An arc length method based nonlinear FEA routine in ABAQUS is used to evaluate the structural performance of the wing and to determine maximum flying velocity that the wing can withstand without buckling or failing under aggressive flight loads. An analytical approach is used to study the stresses developed in the composite wing during storage and Tsai-Wu criterion is used to check failure of the composite wing due to the rolling stresses to determine minimum safe storage diameter. Multidisciplinary wing shape and layup optimization is performed using an elitist non-dominated sorting

  13. Effect of Air Abrasion Preconditioning on Microleakage in Class V Restorations Under Cyclic Loading: An In-vitro Study

    PubMed Central

    Dharmani, Charan Kamal Kaur; Singh, Shamsher; Logani, Ajay; Shah, Naseem

    2014-01-01

    Background: Microleakage in class V Glass Ionomer Cement(GIC) or composite restorations at enamel or cementum margins has been cited as a reason for their failure. Air abrasion has been used to precondition tooth surface for increasing retention of such restorations. This study is done to evaluate the effect of preconditioning with air abrasion on microleakage in class V GIC and composite restorations. Materials and Methods: Class V cavities were prepared in 40 freshly extracted teeth. They were categorised into following four groups (n=10) depending on cavity preconditioning and restoration. Group I: 10% polyacrylic acid and GI (Ketac molar TM 3M ESPE); Group II: AA and GI; Group III: 35% Phosphoric acid and micro filled composite (MC) (Heliomolar, Ivoclar Vivadent); Group IV: AA and MC. Each group was further divided into subgroups A (no loading) & B (cyclic loading). Microleakage at occlusal and gingival margins was evaluated using methylene blue dye penetration method. Statistical analysis was done using Kruskal-wallis test and Mann-Whitney U test. Results: Microleakage at cementum margins was higher than at enamel margins in all the groups. Preconditioning with AA resulted in increased micro leakage. Conclusion: AA as a preconditioning agent was ineffective in producing superior tooth-restoration bonding. PMID:24995240

  14. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... holes, possible breakthrough, and water. Ammonium nitrate blasting agents shall not be loaded into wet holes. (c) Multiple-shot blasts shall be initiated with detonators encased in copper-based alloy shells... be placed at the back or bottom of the hole. (e) Blast holes shall be stemmed with a...

  15. 30 CFR 57.22606 - Explosive materials and blasting units (III mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... holes, possible breakthrough, and water. Ammonium nitrate blasting agents shall not be loaded into wet holes. (c) Multiple-shot blasts shall be initiated with detonators encased in copper-based alloy shells... explosives shall be used only as primers with ammonium nitrate-fuel oil blasting agents. Such primers...

  16. Blast response of a hardened Army ISO shelter

    SciTech Connect

    Milligan, R.W.; Lush, A.; Crenshaw, W.L.

    1982-09-01

    A prototype shelter was designed to withstand a blast loading corresponding to a 10.0 psi (68.9 kPa) incident overpressure. The hardened shelter was then constructed, instrumented and subjected to a simulated nuclear blast loading. Test results demonstrated that a design featuring shear stiffened sandwich panels with aluminum face materials could withstand a nominal 10.0 psi incident shock loading.

  17. Study of loading/air back-pulse cleaning cycles on the performance of ceramic membrane filters

    SciTech Connect

    Waggoner, Charles; Alderman, Steven; Parsons, Michael; Hogoncamp, Kristina; Alderman, Steven

    2007-07-01

    Available in abstract form only. Full text of publication follows: The most commonly identified threats to conventional glass fiber HEPA filter performance are moisture and rapid blinding of filters by smoke. Regenerable filter media composed of ceramics or sintered metal can be utilized as pre-filters to protect the more vulnerable glass fiber HEPA filters in the event of upset conditions. Additionally, used in a pre-filtering application, the use of these regenerable filters can potentially extend the lifetime of conventional units. A series of tests have been conducted using CeraMem ceramic membrane filters in an effort to evaluate their performance after repeated loading and air back pulse cleaning. This was done in an effort to access filter performance after repeated loading/cleaning cycles. The filters were loaded using a solid potassium chloride aerosol challenge. The filters were evaluated for pressure drop and filtering efficiency changes from one cleaning cycle to the next. Additionally, the particle size distribution of the aerosol penetrating the filters was measured. (authors)

  18. Fluid/Structure Interaction Computational Investigation of Blast-Wave Mitigation Efficacy of the Advanced Combat Helmet

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; Bell, W. C.; Pandurangan, B.; Glomski, P. S.

    2011-08-01

    To combat the problem of traumatic brain injury (TBI), a signature injury of the current military conflicts, there is an urgent need to design head protection systems with superior blast/ballistic impact mitigation capabilities. Toward that end, the blast impact mitigation performance of an advanced combat helmet (ACH) head protection system equipped with polyurea suspension pads and subjected to two different blast peak pressure loadings has been investigated computationally. A fairly detailed (Lagrangian) finite-element model of a helmet/skull/brain assembly is first constructed and placed into an Eulerian air domain through which a single planar blast wave propagates. A combined Eulerian/Lagrangian transient nonlinear dynamics computational fluid/solid interaction analysis is next conducted in order to assess the extent of reduction in intra-cranial shock-wave ingress (responsible for TBI). This was done by comparing temporal evolutions of intra-cranial normal and shear stresses for the cases of an unprotected head and the helmet-protected head and by correlating these quantities with the three most common types of mild traumatic brain injury (mTBI), i.e., axonal damage, contusion, and subdural hemorrhage. The results obtained show that the ACH provides some level of protection against all investigated types of mTBI and that the level of protection increases somewhat with an increase in blast peak pressure. In order to rationalize the aforementioned findings, a shockwave propagation/reflection analysis is carried out for the unprotected head and helmet-protected head cases. The analysis qualitatively corroborated the results pertaining to the blast-mitigation efficacy of an ACH, but also suggested that there are additional shockwave energy dissipation phenomena which play an important role in the mechanical response of the unprotected/protected head to blast impact.

  19. Modeling and Control of Aggregated Air Conditioning Loads Under Realistic Conditions

    SciTech Connect

    Chang, Chin-Yao; Zhang, Wei; Lian, Jianming; Kalsi, Karanjit

    2013-02-24

    Demand-side control is playing an increasingly important role in smart grid control strategies. Modeling the dynamical behavior of a large population of appliances is especially important to evaluate the effectiveness of various load control strategies. In this paper, a high accuracy aggregated model is first developed for a population of HVAC units. The model efficiently includes statistical information of the population, systematically deals with heterogeneity, and accounts for a second-order effect necessary to accurately capture the transient dynamics in the collective response. Furthermore, the model takes into account the lockout effect of the compressor in order to represent the dynamics of the system under control more accurately. Then, a novel closed loop load control strategy is designed to track a desired demand curve and to ensure a stable and smooth response.

  20. Decrease in air pollution load in urban environment of Bratislava (Slovakia) inferred from accumulation of metal elements in lichens.

    PubMed

    Guttová, Anna; Lackovičová, Anna; Pišút, Ivan; Pišút, Peter

    2011-11-01

    The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load.

  1. Plutonium Finishing Plant (PFP) Waste Composition and High Efficiency Particulate Air Filter Loading

    SciTech Connect

    ZIMMERMAN, B.D.

    2000-12-11

    This analysis evaluates the effect of the Plutonium Finishing Plant (PFP) waste isotopic composition on Tank Farms Final Safety Analysis Report (FSAR) accidents involving high-efficiency particulate air (HEPA) filter failure in Double-Contained Receiver Tanks (DCRTs). The HEPA Filter Failure--Exposure to High Temperature or Pressure, and Steam Intrusion From Interfacing Systems accidents are considered. The analysis concludes that dose consequences based on the PFP waste isotopic composition are bounded by previous FSAR analyses. This supports USQD TF-00-0768.

  2. Distribution and Rate of Microbial Processes in an Ammonia-Loaded Air Filter Biofilm▿

    PubMed Central

    Juhler, Susanne; Revsbech, Niels Peter; Schramm, Andreas; Herrmann, Martina; Ottosen, Lars D. M.; Nielsen, Lars Peter

    2009-01-01

    The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH3 in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO2−, accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O2 and inhibition by the protonated form of NO2−, HNO2. Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH3 concentration irrespective of variations in inlet concentration and airflow. PMID:19363071

  3. Distribution and rate of microbial processes in an ammonia-loaded air filter biofilm.

    PubMed

    Juhler, Susanne; Revsbech, Niels Peter; Schramm, Andreas; Herrmann, Martina; Ottosen, Lars D M; Nielsen, Lars Peter

    2009-06-01

    The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH(3) in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO(2)(-), accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O(2) and inhibition by the protonated form of NO(2)(-), HNO(2). Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH(3) concentration irrespective of variations in inlet concentration and airflow.

  4. A multi-mode shock tube for investigation of blast-induced traumatic brain injury.

    PubMed

    Reneer, Dexter V; Hisel, Richard D; Hoffman, Joshua M; Kryscio, Richard J; Lusk, Braden T; Geddes, James W

    2011-01-01

    Blast-induced mild traumatic brain injury (bTBI) has become increasingly common in recent military conflicts. The mechanisms by which non-impact blast exposure results in bTBI are incompletely understood. Current small animal bTBI models predominantly utilize compressed air-driven membrane rupture as their blast wave source, while large animal models use chemical explosives. The pressure-time signature of each blast mode is unique, making it difficult to evaluate the contributions of the different components of the blast wave to bTBI when using a single blast source. We utilized a multi-mode shock tube, the McMillan blast device, capable of utilizing compressed air- and compressed helium-driven membrane rupture, and the explosives oxyhydrogen and cyclotrimethylenetrinitramine (RDX, the primary component of C-4 plastic explosives) as the driving source. At similar maximal blast overpressures, the positive pressure phase of compressed air-driven blasts was longer, and the positive impulse was greater, than those observed for shockwaves produced by other driving sources. Helium-driven shockwaves more closely resembled RDX blasts, but by displacing air created a hypoxic environment within the shock tube. Pressure-time traces from oxyhydrogen-driven shockwaves were very similar those produced by RDX, although they resulted in elevated carbon monoxide levels due to combustion of the polyethylene bag used to contain the gases within the shock tube prior to detonation. Rats exposed to compressed air-driven blasts had more pronounced vascular damage than those exposed to oxyhydrogen-driven blasts of the same peak overpressure, indicating that differences in blast wave characteristics other than peak overpressure may influence the extent of bTBI. Use of this multi-mode shock tube in small animal models will enable comparison of the extent of brain injury with the pressure-time signature produced using each blast mode, facilitating evaluation of the blast wave components

  5. A Multi-Mode Shock Tube for Investigation of Blast-Induced Traumatic Brain Injury

    PubMed Central

    Reneer, Dexter V.; Hisel, Richard D.; Hoffman, Joshua M.; Kryscio, Richard J.; Lusk, Braden T.

    2011-01-01

    Abstract Blast-induced mild traumatic brain injury (bTBI) has become increasingly common in recent military conflicts. The mechanisms by which non-impact blast exposure results in bTBI are incompletely understood. Current small animal bTBI models predominantly utilize compressed air-driven membrane rupture as their blast wave source, while large animal models use chemical explosives. The pressure-time signature of each blast mode is unique, making it difficult to evaluate the contributions of the different components of the blast wave to bTBI when using a single blast source. We utilized a multi-mode shock tube, the McMillan blast device, capable of utilizing compressed air- and compressed helium-driven membrane rupture, and the explosives oxyhydrogen and cyclotrimethylenetrinitramine (RDX, the primary component of C-4 plastic explosives) as the driving source. At similar maximal blast overpressures, the positive pressure phase of compressed air-driven blasts was longer, and the positive impulse was greater, than those observed for shockwaves produced by other driving sources. Helium-driven shockwaves more closely resembled RDX blasts, but by displacing air created a hypoxic environment within the shock tube. Pressure-time traces from oxyhydrogen-driven shockwaves were very similar those produced by RDX, although they resulted in elevated carbon monoxide levels due to combustion of the polyethylene bag used to contain the gases within the shock tube prior to detonation. Rats exposed to compressed air-driven blasts had more pronounced vascular damage than those exposed to oxyhydrogen-driven blasts of the same peak overpressure, indicating that differences in blast wave characteristics other than peak overpressure may influence the extent of bTBI. Use of this multi-mode shock tube in small animal models will enable comparison of the extent of brain injury with the pressure-time signature produced using each blast mode, facilitating evaluation of the blast wave

  6. The role of loading rate, backwashing, water and air velocities in an up-flow nitrifying tertiary filter.

    PubMed

    Vigne, Emmanuelle; Choubert, Jean-Marc; Canler, Jean-Pierre; Heduit, Alain; Sørensen, Kim Helleshøj; Lessard, Paul

    2011-01-01

    The vertical distribution of nitrification performances in an up-flow biological aerated filter operated at tertiary nitrification stage is evaluated in this paper. Experimental data were collected from a semi-industrial pilot-plant under various operating conditions. The actual and the maximum nitrification rates were measured at different levels inside the up-flow biofilter. A nitrogen loading rate higher than 1.0 kg NH4-Nm(-3)_mediad(-1) is necessary to obtain nitrification activity over all the height of the biofilter. The increase in water and air velocities from 6 to 10 m h(-1) and 10 to 20 m h(-1) has increased the nitrification rate by 80% and 20% respectively. Backwashing decreases the maximum nitrification rate in the media by only 3-14%. The nitrification rate measured at a level of 0.5 m above the bottom of the filter is four times higher than the applied daily average volumetric nitrogen loading rate up to 1.5 kg NH4-N m(-3)_mediad(-1). Finally, it is shown that 58% of the available nitrification activity is mobilized in steady-state conditions while up to 100% is used under inflow-rate increase. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. 1. View of blast deflector fences along southwest side of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View of blast deflector fences along southwest side of the operational apron. View to west. - Offutt Air Force Base, Looking Glass Airborne Command Post, Blast Deflector Fences, Northeast & Southwest sides of Operational Apron, Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  8. 2. View of blast deflector fences along northeast side of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. View of blast deflector fences along northeast side of the operational apron. View to northwest. - Offutt Air Force Base, Looking Glass Airborne Command Post, Blast Deflector Fences, Northeast & Southwest sides of Operational Apron, Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  9. Researching Complex Heat, Air and Moisture Interactions for a Wide-Range of Building Envelope Systems and Environmental Loads

    SciTech Connect

    Karagiozis, A.N.

    2007-05-15

    This document serves as the final report documenting work completed by Oak Ridge National Laboratory (ORNL) and the Fraunhofer Institute in Building Physics (Holzkirchen, Germany) under an international CRADA No. 0575 with Fraunhofer Institute of Bauphysics of the Federal Republic of Germany for Researching Complex Heat, Air and Moisture Interactions for a Wide Range of Building Envelope Systems and Environmental Loads. This CRADA required a multi-faceted approach to building envelope research that included a moisture engineering approach by blending extensive material property analysis, laboratory system and sub-system thermal and moisture testing, and advanced moisture analysis prediction performance. The Participant's Institute for Building physics (IBP) and the Contractor's Buildings Technology Center (BTC) identified potential research projects and activities capable of accelerating and advancing the development of innovative, low energy and durable building envelope systems in diverse climates. This allowed a major leverage of the limited resources available to ORNL to execute the required Department of Energy (DOE) directives in the area of moisture engineering. A joint working group (ORNL and Fraunhofer IBP) was assembled and a research plan was executed from May 2000 to May 2005. A number of key deliverables were produced such as adoption of North American loading into the WUFI-software. in addition the ORNL Weather File Analyzer was created and this has been used to address environmental loading for a variety of US climates. At least 4 papers have been co-written with the CRADA partners, and a chapter in the ASTM Manual 40 on Moisture Analysis and Condensation Control. All deliverables and goals were met and exceeded making this collaboration a success to all parties involves.

  10. Investigation of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings

    SciTech Connect

    Suilou Huang; Stephen D. Schery; John C. Rodgers

    2002-07-23

    A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures.

  11. Copper staves in the blast furnace

    SciTech Connect

    Helenbrook, R.G.; Kowalski, W.; Grosspietsch, K.H.; Hille, H.

    1996-08-01

    Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that the MAN GHH copper staves do not experience large temperature fluctuations and that the hot face temperatures will be below 250 F. This suggests that the copper staves maintain a more stable accretion layer than the cast iron staves. Contrary to initial expectations, heat flux to the copper staves is 50% lower than that to cast iron staves. The more stable accretion layer acts as an excellent insulator for the stave and greatly reduces the number of times the hot face of the stave is exposed to the blast furnace process and should result in a more stable furnace operation. In the future, it may be unnecessary to use high quality, expensive refractories in front of copper staves because of the highly stable accretion layer that appears to rapidly form due to the lower operating temperature of the staves. There is a balance of application regions for cast iron and copper staves that minimizes the capital cost of a blast furnace reline and provides an integrated cooling system with multiple campaign life potential. Cast iron staves are proven cooling elements that are capable of multiple campaign life in areas of the blast furnace which do not experience extreme heat loads. Copper staves are proving to be an effective and reliable blast furnace cooling element that are subject to virtually no wear and are projected to have a longer campaign service life in the areas of highest thermal load in the blast furnace.

  12. Experimental study of blast mitigating devices based on combined construction

    NASA Astrophysics Data System (ADS)

    Takayama, K.; Silnikov, M. V.; Chernyshov, M. V.

    2016-09-01

    A robust blast inhibiting bin is the most often used device for damage blast effects suppression. In particular, a top open cylindrical bin significantly reduces a fragmentation effect resulted from a detonation of an explosive device placed inside the bin. However, reduction of blast wave overpressure and impulse by such cylindrical bins is not sufficient [1]. A reasonable alternative to endless increase of height and thickness of robust blast inhibiting bins is a development of destructible inhibitors having no solid elements in their structure and, therefore, excluding secondary fragmentation. So, the family of "Fountain" inhibitors [2,3] localizes and suppresses damaging blast effects due to multiphase working system. The present study is analyzing data obtained in testing of prototypes of new combined inhibitors. Their structure combines robust elements (bottoms, side surfaces) with elements responsible for blast loads reduction due to multi-phase working system (top and low transverse embeddings) and fairings impeding wave propagation in undesirable directions.

  13. Automated Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Pickett, Isaiah R.; Yulfo, Alyce R.

    1992-01-01

    Automatic grit-blasting machine removes melted-layer residue from electrical-discharge-machined surfaces of turbine blades. Automatic control system of machine provides steady flow of grit and maintains blast nozzles at proper distance and in correct orientation perpendicular to surface being blasted, regardless of contour. Eliminates localized excessive blasting and consequent excessive removal of underlying material, blasting of adjacent surfaces, and missed areas.

  14. Note: Device for underwater laboratory simulation of unconfined blast waves.

    PubMed

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-06-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast pressures of about 1860 kPa. Shot-to-shot consistency was fair, with an average standard deviation near 150 kPa. Results suggest that peak blast pressures from 460 kPa to 1860 kPa are available by adjusting the distance from the source.

  15. Note: Device for underwater laboratory simulation of unconfined blast waves

    NASA Astrophysics Data System (ADS)

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-06-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast pressures of about 1860 kPa. Shot-to-shot consistency was fair, with an average standard deviation near 150 kPa. Results suggest that peak blast pressures from 460 kPa to 1860 kPa are available by adjusting the distance from the source.

  16. Two lighter than air systems in opposing flight regimes: An unmanned short haul, heavy load transport balloon and a manned, light payload airship

    NASA Technical Reports Server (NTRS)

    Pohl, R. A.

    1975-01-01

    Lighter Than Air vehicles are generally defined or categorized by the shape of the balloon, payload capacity and operational flight regime. Two balloon systems that are classed as being in opposite categories are described. One is a cable guided, helium filled, short haul, heavy load transport Lighter Than Air system with a natural shaped envelope. The other is a manned, aerodynamic shaped airship which utilizes hot air as the buoyancy medium and is in the light payload class. While the airship is in the design/fabrication phase with flight tests scheduled for the latter part of 1974, the transport balloon system has been operational for some eight years.

  17. On firework blasts and qualitative parameter dependency

    PubMed Central

    Zohdi, T. I.

    2016-01-01

    In this paper, a mathematical model is developed to qualitatively simulate the progressive time-evolution of a blast from a simple firework. Estimates are made for the blast radius that one can expect for a given amount of detonation energy and pyrotechnic display material. The model balances the released energy from the initial blast pulse with the subsequent kinetic energy and then computes the trajectory of the material under the influence of the drag from the surrounding air, gravity and possible buoyancy. Under certain simplifying assumptions, the model can be solved for analytically. The solution serves as a guide to identifying key parameters that control the evolving blast envelope. Three-dimensional examples are given. PMID:26997903

  18. Blast furnace supervision and control system

    SciTech Connect

    Remorino, M.; Lingiardi, O.; Zecchi, M.

    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.

  19. Main rotor free wake geometry effects on blade air loads and response for helicopters in steady maneuvers. Volume 2: Program listings

    NASA Technical Reports Server (NTRS)

    Sadler, S. G.

    1972-01-01

    A mathematical model and computer program was implemented to study the main rotor free wake geometry effects on helicopter rotor blade air loads and response in steady maneuvers. Volume 1 (NASA CR-2110) contains the theoretical formulation and analysis of results. Volume 2 contains the computer program listing.

  20. Chemical characteristics of atmospheric PM2.5 loads during air pollution episodes in Giza, Egypt

    NASA Astrophysics Data System (ADS)

    Hassan, Salwa K.; Khoder, Mamdouh I.

    2017-02-01

    Several types of pollution episodes, including dust storm (DSs), haze dust (HDs), straw rice combustions (SRCs) are common phenomena and represent severe environmental hazard in Egypt. This study provides the first comprehensive analysis of the chemical characteristics of aerosol during air pollution episodes at an urban area in Giza, Egypt. PM2.5 samples during various PM episodes during 2013-2014 were collected and analyzed. Results indicate that the highest PM2.5 mass concentrations were found during DSs (250 μg/m3), followed by HDs (130 μg/m3) and SRCs (103 μg/m3). Average PM2.5 mass concentrations were 1.91, 3.68 and 1.68 times higher than on normal days (NDs) during HDs, DSs and SRCs, respectively. The highest total water-soluble ions concentration was 61.1 μg/m3 during HDs, followed by SRCs (41.9 μg/m3) and DSs (35.2 μg/m3). SO42- is the most abundant chemical components on the three PM episodes. Secondary inorganic ions (NO3-, SO42-, and NH4+) were enriched during HDs. The total secondary inorganic ions concentrations were 3.17, 1.39 and 1.75 times higher than NDs during HDs days, DSs days and SRCs days, respectively. PM from SRCs showed high K+ and Cl-. SO42-/K+, NO3-/SO42- and Cl-/K+ ratios proved effective as indicators for different pollution episodes. A Ca2+/Al ratio indicates that soil dust was dominant during DSs. Ion balance calculations indicated that PM2.5 from HDs was acidic, while the DSs and SRCs particles were alkaline and the NDs particle's was nearly neutral. The total crustal and anthropogenic metals concentrations were higher in DSs than other PM episodes and normal days. The enrichment factors values in PM episodes and normal days indicate that Fe and Mn in NDs, HDs, DSs and SRCs as well as Cr and Ni in DSs come mainly from crustal sources, whereas Cr, Ni, Co, Cu, Zn, Pb and Cd in PM episodes and NDs are anthropogenic.

  1. Performance characteristics of part-load operations of a solid oxide fuel cell/gas turbine hybrid system using air-bypass valves

    NASA Astrophysics Data System (ADS)

    Yang, Jin Sik; Sohn, Jeong L.; Ro, Sung Tack

    In spite of the high-performance characteristics of a solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system, it is difficult to maintain high-level performance under real application conditions, which generally require part-load operations. The efficiency loss of the SOFC/GT hybrid system under such conditions is closely related to that of the gas turbine. The power generated by the gas turbine in a hybrid system is much less than that generated by the SOFC, but its contribution to the efficiency of the system is important, especially under part-load conditions. Over the entire operating load profile of a hybrid system, the efficiency of the hybrid system can be maximized by increasing the contribution of power coming from the high efficiency component, namely the fuel cell. In this study, part-load control strategies using air-bypass valves are proposed, and their impact on the performance of an SOFC/GT hybrid system is discussed. It is found that air-bypass modes with control of the fuel supply help to overcome the limits of the part-load operation characteristics in air/fuel control modes, such as variable rotational speed control and variable inlet guide vane control.

  2. Analytical Assessment of the Blast Resistance of Precast, Prestressed Concrete Components (PREPRINT)

    DTIC Science & Technology

    2007-04-01

    Load Bearing Reinforced Concrete Shear Walls”, ASCE Practical Periodical on Structural Design and Construction , V. 11, No. 2, May...To illustrate this concept, the blast resistances of non- load bearing precast , prestressed concrete sandwich wall panels (WP) are examined. These...previous sections allow a designer to effectively analyze the blast capacity of a precast , prestressed concrete wall panel. The iso-damage

  3. 4. DETAIL SHOWING PROTECTIVE BLAST WALL AND EMERGENCY EYEWASH AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL SHOWING PROTECTIVE BLAST WALL AND EMERGENCY EYE-WASH AND SHOWER AREA; VIEW TO SOUTHWEST. - Cape Canaveral Air Station, Launch Complex 17, Facility 28405, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  4. 24. GENERAL VIEW OF NEW CONCRETE BLAST BERM FOR NEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. GENERAL VIEW OF NEW CONCRETE BLAST BERM FOR NEW LIQUID HYDROGEN TANK FARM; VIEW TO EAST. - Cape Canaveral Air Station, Launch Complex 17, Facility 28402, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  5. 27. Launch Control Center, blast door at left, view from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. Launch Control Center, blast door at left, view from tunnel junction. Lyon - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

  6. DETAIL VIEW OF A CAMERA PEDESTAL ON THE BLAST DECK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF A CAMERA PEDESTAL ON THE BLAST DECK OF THE 0 LEVEL - Cape Canaveral Air Force Station, Launch Complex 39, Mobile Launcher Platforms, Launcher Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  7. secureBLAST.

    PubMed

    Wiezer, Arnim; Merkl, Rainer

    2003-01-01

    secureBLAST supplements NCBI wwwblast with features necessary to control in an easy manageable way usage of BLAST data sets and their update. The concept we implemented allows to offer on a single BLAST server several data sets with individually configurable access rights. Security is provided by user authentication and encryption of the http traffic via SSL. By using secureBLAST, the administration of users and databases can be done via a web interface. Therefore, secureBLAST is valuable for institutions that have to restrict access to their datasets or just want to administer BLAST servers via a web interface.

  8. Air-To-Water Heat Pumps with Radiant Delivery in Low Load Homes: Tucson, Arizona and Chico, California (Fact Sheet)

    SciTech Connect

    None, None

    2013-11-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  9. BLAST: Building energy simulation in Hong Kong

    NASA Astrophysics Data System (ADS)

    Fong, Sai-Keung

    1999-11-01

    The characteristics of energy use in buildings under local weather conditions were studied and evaluated using the energy simulation program BLAST-3.0. The parameters used in the energy simulation for the study and evaluation include the architectural features, different internal building heat load settings and weather data. In this study, mathematical equations and the associated coefficients useful to the industry were established. A technology for estimating energy use in buildings under local weather conditions was developed by using the results of this study. A weather data file of Typical Meteorological Years (TMY) has been compiled for building energy studies by analyzing and evaluating the weather of Hong Kong from the year 1979 to 1988. The weather data file TMY and the example weather years 1980 and 1988 were used by BLAST-3.0 to evaluate and study the energy use in different buildings. BLAST-3.0 was compared with other building energy simulation and approximation methods: Bin method and Degree Days method. Energy use in rectangular compartments of different volumes varying from 4,000 m3 to 40,000 m3 with different aspect ratios were analyzed. The use of energy in buildings with concrete roofs was compared with those with glass roofs at indoor temperature 21°C, 23°C and 25°C. Correlation relationships among building energy, space volume, monthly mean temperature and solar radiation were derived and investigated. The effects of space volume, monthly mean temperature and solar radiation on building energy were evaluated. The coefficients of the mathematical relationships between space volume and energy use in a building were computed and found satisfactory. The calculated coefficients can be used for quick estimation of energy use in buildings under similar situations. To study energy use in buildings, the cooling load per floor area against room volume was investigated. The case of an air-conditioned single compartment with 5 m ceiling height was

  10. A new approach to oxygen enriched high temperature blast generation

    SciTech Connect

    Queille, P.H.; Macauley, D.

    1996-12-31

    When increasing fuel injection in a blast furnace in order to reduce coke consumption and/or to increase production, the blast furnace operator tries to keep similar raceway conditions, for instance, an equivalent flame temperature. To compensate for the cooling effect due to the higher injection rate, two solutions can be selected or combined: to raise the temperature of the blast and/or to increase the level of oxygen in the blast. Whatever the choice, the Blast Furnace manager will certainly try to reduce the resulting investment and operating costs to a minimum. Air Liquide and Kvaerner Davy are trying to provide a new way to address these needs by offering a new technology for blast heating. A higher blast temperature will not only allow a higher fuel injection at tuyere level, a lower coke consumption, but also a lower oxygen consumption. Air Liquide and Kvaerner Davy are now able to offer a new heat regenerator with major advantages over conventional stoves. This new device can be used as a permanent substitute for a stove, or as a temporary one during repair, or stove improvement. It can also be added to an existing set of stoves to increase the average blast temperature.

  11. Modelling and Testing of Blast Effect On the Structures

    NASA Astrophysics Data System (ADS)

    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.

  12. Close-in Blast Waves from Spherical Charges*

    NASA Astrophysics Data System (ADS)

    Howard, William; Kuhl, Allen

    2011-06-01

    We study the close-in blast waves created by the detonation of spherical high explosives (HE) charges, via numerical simulations with our Arbitrary-Lagrange-Eulerian (ALE3D) code. We used a finely-resolved, fixed Eulerian 2-D mesh (200 μm per cell) to capture the detonation of the charge, the blast wave propagation in air, and the reflection of the blast wave from an ideal surface. The thermodynamic properties of the detonation products and air were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. The results were analyzed to evaluate the: (i) free air pressure-range curves: Δps (R) , (ii) free air impulse curves, (iii) reflected pressure-range curves, and (iv) reflected impulse-range curves. A variety of explosives were studied. Conclusions are: (i) close-in (R < 10 cm /g 1 / 3) , each explosive had its own (unique) blast wave (e.g., Δps (R , HE) ~ a /Rn , where n is different for each explosive); (ii) these close-in blast waves do not scale with the ``Heat of Detonation'' of the explosive (because close-in, there is not enough time to fully couple the chemical energy to the air via piston work); (iii) instead they are related to the detonation conditions inside the charge. Scaling laws will be proposed for such close-in blast waves.

  13. Modeling of Near-Field Blast Performance

    DTIC Science & Technology

    2013-11-01

    time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the...The freeze-out temperature is chosen by comparison of calorimetry experiments (2, 3) and thermoequilibrium calculations using CHEETAH (4). The near...P.; Vitello, P. CHEETAH Users Manual; Lawrence Livermore National Laboratory: Livermore, CA, 2012. 5. Walter, P. Introduction to Air Blast

  14. The environment of nature reserves under anthropogenic load: air transport of pollution to the North of European Russia

    NASA Astrophysics Data System (ADS)

    Vinogradova, A. A.; Ivanova, Yu. A.; Veremeychik, A. O.

    2012-04-01

    Nature reserves are created to keep in their original states natural environment, flora and fauna of various ecological systems, territories, climatic zones, etc. Now natural objects everywhere exist under anthropogenic loading from man-made activities. It is impossible to avoid atmospheric or river transport of pollution to the environment of reserved territories. The main idea of the work is to analyze atmospheric transport of anthropogenic metals (Ni, Cu, Pb, Fe, Al), as well as of soot (black carbon - BC) from Russian large industrial areas (source-regions) to the territories of nature reserves at the North of European Russia - the Kostomukshsky reserve (KR) in Karelia (64.57°N, 30.67°E) and the Nenetzky reserve (NR) at the Pechora River mouth (68,5°N, 53,5°E). The basic data for these 2 points were back trajectories of air mass transport calculated for every day of January, April, July, and October during 10 years from 2001 to 2010. We used NCEP/NCAR Reanalysis Data Files with HYSPLIT 4 model and two approaches for analyzing the trajectories. The main source-regions were chosen for each reserve. The annual source emissions for the last decade are generalized from the data published by Roshydromet of Russia (http://www.nii-atmosphere.ru/files/PUBL/Eg_2008.doc). The deposition velocity was a sum of dry and wet components. The equal values of deposition velocities onto the surface were assumed for all impurities because they are mainly on submicron aerosol particles under atmospheric transport for a long distance. The seasonal and spatial variations of averaged deposition velocity were accounted in accordance with surface properties and precipitation regimes. As a result, the maximal air concentrations of aerosol pollutants are observed in cold seasons, whereas the maximal fluxes onto the surface occur in warm period. Thus, it's possible that the cleanest air does not indicate the same surface. Fe and Al are the crust (dust or soil) elements. Thus, their main

  15. Dynamic test of a corrugated steel keyworker blast shelter. Final report

    SciTech Connect

    Woodson, S.C.; Slawson, T.R.; Holmes, R.L.

    1986-05-01

    At the time this study was initiated, civil defense planning in the United States called for the evacuation of nonessential personnel to safe host areas when a nuclear attack is probable, requiring the construction of blast shelters to protect the key workers remaining in the risk areas. A full-scale corrugated steel keyworker blast shelter was dynamically tested using the High Explosive Simulation Technique (HEST). The test primarily investigated the structural design of the shelter and entryway, survivability of the air-moving system components, and occupant survivability. Alternate blast designs for the 18-man shelter were also tested. The test showed that the structure can withstand a 55-psi peak overpressure loading from a 1-MT nuclear detonation with only minor damage. In-structure shock was within acceptable limits for occupants. However, typical floor-mounted shelter equipment should be shock-isolated with pads to ensure survivability. Structural modifications to decrease the cost and increase the ease of installation of the structure are recommended.

  16. Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

    NASA Astrophysics Data System (ADS)

    Azizi, Mohammad Ali; Brouwer, Jacob

    2017-10-01

    A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

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

    PubMed

    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.

  18. Recent improvements in casthouse practices at the Kwangyang blast furnaces

    SciTech Connect

    Jang, Y.S.; Han, K.W.; Kim, K.Y.; Cho, B.R.; Hur, N.S.

    1997-12-31

    POSCO`s Kwangyang blast furnaces have continuously carried out high production and low fuel operation under a high pulverized coal injection rate without complications since the Kwangyang No. 1 blast furnace was blown-in in 1987. The Kwangyang blast furnaces have focused on improving the work environment for the increase of competitive power in terms of increased production, cost savings, and management of optimum manpower through use of low cost fuel and raw material. At this time, the casthouse work lags behind most work in the blast furnace. Therefore, the Kwangyang blast furnaces have adopted a remote control system for the casthouse equipment to solve complications in the casthouse work due to high temperature and fumes. As the result, the casthouse workers can work in clean air and the number of workers has been reduced to 9.5 personnel per shift by reduction of the workload.

  19. Performance of Blast-Damaged Steel Connections in Progressive Collapse

    DTIC Science & Technology

    2010-10-01

    part of a multi-phase program including blast tests of steel columns and base plates (2,3). In this paper, the multi-phase test program is briefly...the discussion. TEST PROGRAM The objective of the test program was to determine the response of steel columns, base plates , and beam-to-column...Phase I, the objective was to study the response of typical and blast-resistant base plate connec- tions to blast loading. Phase II was a study of the

  20. Measurement of transmitted blast force-time histories

    SciTech Connect

    Dr. Benjamin Langhorst; Corey Cook; James Schondel; Dr. Henry S. Chu

    2010-03-01

    A simple, reliable, and cost effective method is presented for the measurement of transmitted force behind a panel subjected to blast loads. Sensors were designed for a specific blast environment and successfully used to measure transmitted blast force behind solid polyethylene plates of thickness 0.125 and 0.25 inches. Experimental data was collected and examined to reveal consistent differences in the response of different thicknesses of otherwise identical panels. Finally, recommendations are made for future design, construction and use of similar sensors.

  1. Blast assessment and optimization for high quarry face-blasting

    SciTech Connect

    Sames, F.; O`Meara, R.

    1996-12-01

    Where applicable, high production benches can improve efficiency in quarrying. Quality control, geological, cost or other considerations might result in the development of quarry benches higher than 30 m and sometimes up to 60 m. Production blasts on high quarry faces require a confident blast design with respect to safety, cost efficiency and minimized environmental effects. Careful pre-blast assessment of the design parameters, blast monitoring of the product performance and the environmental effects and post-blast assessment of the overall blast performance are essential for the successful implementation of the blast design. The blast geometry for high quarry faces and a blast design that often includes multiple explosive charges in a blasthole, make a reliable assessment of the blast parameters difficult. Assessment techniques, their applications and limitations are described and discussed. This will include such methods as blast surveying using laser profiling and borehole deviation measurements, blast monitoring using continuous velocity of detonation measurement systems, high speed photography and seismographs for blast performance and environmental effects. Observations of low frequency airblast and high standard deviations in ground vibration measurements are described and discussed against a background of timing assessment and frequency spectra analysis. Approaches where an optimized design was implemented based on the blast parameter assessment and modeling are presented. An improvement in blast efficiency lies in the combination of blast assessment and blast modeling, whilst adequate documentation supports the process of designing and implementing successful blasts.

  2. Modeling Blast Wave Propagation in a Generic Facility

    DTIC Science & Technology

    2010-10-01

    depends on the extent of failure of the interior walls surrounding the blast. As the walls fail, the propagating airblast convects the wall debris to...resulting from an internal detonation is a coupled fluid and structural dynamics problem that depends on the extent of failure of the interior walls...FEFLO and CHEETAH , and the structural response to the blast loading using the coupled CFD and CSD methodology, where the structural domain is embedded

  3. [The disguised face of blast injuries: shock waves].

    PubMed

    Ozer, M Tahir; Coşkun, Kağan; Oğünç, Gökhan I; Eryılmaz, Mehmet; Yiğit, Taner; Kozak, Orhan; Apaydın, Kanbi; Uzar, A Ihsan

    2010-09-01

    The increase in terrorist attacks has brought a profound and new knowledge of blast injuries. In order to improve our knowledge regarding the mechanisms of blast injuries, we analyzed the effects of shock waves. 100 g TNT and 1000 g C4 were detonated and recorded by high-speed camera. Blast wind, shock wave and shrapnel speeds were calculated, and final condition of the target was examined. A flash ball appeared first followed by the shock wave. Finally, blast wind occurred and shrapnel was distributed. The macroscopic structure of targets was not affected by the shock wave but was affected by shrapnel and blast wind. Shock waves created a transparent ballistic gel inside the target mat by changing its microscopic structure. The speed of the shock wave was 6482-7194 m/sn and shrapnel speed was 1420-1752 m/sn. Shock waves especially affect the air-filled organs and cause lung injury, acute respiratory distress syndrome, and intestinal and eardrum perforation. Blast wind destroys targets due to its high speed and high density. The main cause of mortality is shrapnel injury. The high temperature created by the explosion causes thermal injuries. Being informed of the mechanisms of blast injuries will assist in providing better treatment. Additionally, consideration of all mechanisms of blast injuries will facilitate lower mortality and morbidity rates.

  4. Blast overpressure after tire explosion: a fatal case.

    PubMed

    Pomara, Cristoforo; D'Errico, Stefano; Riezzo, Irene; Perilli, Gabriela; Volpe, Umberto; Fineschi, Vittorio

    2013-12-01

    Fatal blast injuries are generally reported in literature as a consequence of the detonation of explosives in war settings. The pattern of lesion depends on the position of the victim in relation to the explosion, on whether the blast tracks through air or water, and whether it happens in the open air or within an enclosed space and the distance from the explosion. Tire explosion-related injuries are rarely reported in literature. This study presents a fatal case of blast overpressure due to the accidental explosion of a truck tire occurring in a tire repair shop. A multidisciplinary approach to the fatality involving forensic pathologists and engineers revealed that the accidental explosion, which caused a series of primary and tertiary blast wave injuries, was due to tire deterioration.

  5. Crack Propagation During Sustained-Load Cracking of Al-Zn-Mg-Cu Aluminum Alloys Exposed to Moist Air or Distilled Water

    NASA Astrophysics Data System (ADS)

    Holroyd, N. J. Henry; Scamans, G. M.

    2011-12-01

    Intergranular sustained-load cracking of Al-Zn-Mg-Cu (AA7xxx series) aluminum alloys exposed to moist air or distilled water at temperatures in the range 283 K to 353 K (10 °C to 80 °C) has been reviewed in detail, paying particular attention to local processes occurring in the crack-tip region during crack propagation. Distinct crack-arrest markings formed on intergranular fracture faces generated under fixed-displacement loading conditions are not generated under monotonic rising-load conditions, but can form under cyclic-loading conditions if loading frequencies are sufficiently low. The observed crack-arrest markings are insensitive to applied stress intensity factor, alloy copper content and temper, but are temperature sensitive, increasing from ~150 nm at room temperature to ~400 nm at 313 K (40 °C). A re-evaluation of published data reveals the apparent activation energy, E a for crack propagation in Al-Zn-Mg(-Cu) alloys is consistently ~35 kJ/mol for temperatures above ~313 K (40 °C), independent of copper content or the applied stress intensity factor, unless the alloy contains a significant volume fraction of S-phase, Al2CuMg where E a is ~80 kJ/mol. For temperatures below ~313 K (40 °C) E a is independent of copper content for stress intensity factors below ~14 MNm-3/2, with a value ~80 kJ/mol but is sensitive to copper content for stress intensity factors above ~14 MNm-3/2, with E a , ranging from ~35 kJ/mol for copper-free alloys to ~80 kJ/mol for alloys containing 1.5 pct Cu. The apparent activation energy for intergranular sustained-load crack initiation is consistently ~110 kJ/mol for both notched and un-notched samples. Mechanistic implications are discussed and processes controlling crack growth, as a function of temperature, alloy copper content, and loading conditions are proposed that are consistent with the calculated apparent activation energies and known characteristics of intergranular sustained-load cracking. It is suggested

  6. Hot blast stove process model and model-based controller

    SciTech Connect

    Muske, K.R.; Howse, J.W.; Hansen, G.A.; Cagliostro, D.J.; Chaubal, P.C.

    1998-12-31

    This paper describes the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed and verified using plant data. This model is used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The model is also used to predict maximum and minimum temperature constraint violations within the stove so that the controller can take corrective actions while still achieving the required stove performance.

  7. Regulating air quality through the use of total daily maximum load standards for designated airsheds: A conceptual outline and analysis of meteorological constraints

    SciTech Connect

    Mendola, F.P.; Oppenfeld, R.R. von; Hiser, E.L.

    1996-12-31

    Congress enacted the Clean Air Act Amendments of 1990 in response to concerns that there was widespread noncompliance with air pollution control requirements. In seeking to address noncompliance, Congress turned to the successful National Pollutant Discharge Elimination System (NPDES) permitting program enacted under the Clean Water Act as a model for a federally-mandated operating permit program. Congress` decision to turn to the Clean Water Act to resolve intractable problems in air quality permitting and enforcement suggests that Congress may turn to other Clean Water Act programs, such as the concept of regulating total maximum daily load (TMDL)--the maximum amount of pollutant that can be added to a given stream segment from all sources without violating water quality standards, to address continued nonattainment of the Clean Air Act`s national ambient air quality standards. This paper investigates the applying the TMDL model to airsheds, sets forth a conceptual outline for such a regulatory approach, and analyzes the meteorological and modeling constraints on successful implementation.

  8. Mystery of Foil Air Bearings for Oil-free Turbomachinery Unlocked: Load Capacity Rule-of-thumb Allows Simple Estimation of Performance

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2002-01-01

    The Oil-Free Turbomachinery team at the NASA Glenn Research Center has unlocked one of the mysteries surrounding foil air bearing performance. Foil air bearings are self-acting hydrodynamic bearings that use ambient air, or any fluid, as their lubricant. In operation, the motion of the shaft's surface drags fluid into the bearing by viscous action, creating a pressurized lubricant film. This lubricating film separates the stationary foil bearing surface from the moving shaft and supports load. Foil bearings have been around for decades and are widely employed in the air cycle machines used for cabin pressurization and cooling aboard commercial jetliners. The Oil-Free Turbomachinery team is fostering the maturation of this technology for integration into advanced Oil-Free aircraft engines. Elimination of the engine oil system can significantly reduce weight and cost and could enable revolutionary new engine designs. Foil bearings, however, have complex elastic support structures (spring packs) that make the prediction of bearing performance, such as load capacity, difficult if not impossible. Researchers at Glenn recently found a link between foil bearing design and load capacity performance. The results have led to a simple rule-of-thumb that relates a bearing's size, speed, and design to its load capacity. Early simple designs (Generation I) had simple elastic (spring) support elements, and performance was limited. More advanced bearings (Generation III) with elastic supports, in which the stiffness is varied locally to optimize gas film pressures, exhibit load capacities that are more than double those of the best previous designs. This is shown graphically in the figure. These more advanced bearings have enabled industry to introduce commercial Oil-Free gas-turbine-based electrical generators and are allowing the aeropropulsion industry to incorporate the technology into aircraft engines. The rule-of-thumb enables engine and bearing designers to easily size and

  9. Bomb blast mass casualty incidents: initial triage and management of injuries.

    PubMed

    Goh, S H

    2009-01-01

    Bomb blast injuries are no longer confined to battlefields. With the ever present threat of terrorism, we should always be prepared for bomb blasts. Bomb blast injuries tend to affect air-containing organs more, as the blast wave tends to exert a shearing force on air-tissue interfaces. Commonly-injured organs include the tympanic membranes, the sinuses, the lungs and the bowel. Of these, blast lung injury is the most challenging to treat. The clinical picture is a mix of acute respiratory distress syndrome and air embolism, and the institution of positive pressure ventilation in the presence of low venous pressures could cause systemic arterial air embolism. The presence of a tympanic membrane perforation is not a reliable indicator of the presence of a blast injury in the other air-containing organs elsewhere. Radiological imaging of the head, chest and abdomen help with the early identification of blast lung injury, head injury, abdominal injury, eye and sinus injuries, as well as any penetration by foreign bodies. In addition, it must be borne in mind that bomb blasts could also be used to disperse radiological and chemical agents.

  10. Molecular Changes and Vision Loss in a Mouse Model of Closed-Globe Blast Trauma

    PubMed Central

    Bricker-Anthony, Courtney; Hines-Beard, Jessica; Rex, Tonia S.

    2014-01-01

    Purpose. To characterize retinal changes and assess vision after an eye-directed air blast. Methods. Adult C57Bl/6 mice were exposed to a blast directed at one eye. Optical coherence tomography and histology were performed to assess retina and optic nerve integrity. Cell death, oxidative stress, and glial reactivity were examined by immunohistochemistry. Visual changes were measured by ERG recordings and the optokinetic reflex. Results. In the outer retina, eye blast caused retinal pigment epithelium vacuoles and rare retinal detachments followed by regional cell death. Labeling for nitrotyrosine and markers of pyroptosis (caspase-1) and necroptosis (receptor-interacting protein kinases-1, -3) increased, primarily in the inner retina, after blast. Caspase-1 labeling was restricted primarily to the starburst amacrine cells. A few degenerating axons were detected at 28 days post blast. Despite a lack of substantial cell death or decreased ERG, there was a deficit in visual acuity after blast. Conclusions. Oxidative stress, neuroinflammation, and cell death became increasingly prevalent, over time post blast suggestive of an ongoing neurodegenerative response. Outer retinal changes either resolved or remained focal. In contrast, inner retinal changes were more robust and spread from focal regions to the entire retina over time post blast. Our model of eye blast trauma causes molecular changes and a decrease in visual acuity within the first month post blast despite a lack of overt eye injury. This subtle response matches the delayed presentation of visual deficits in some blast-exposed Veterans. PMID:24994864

  11. Dry ice blasting

    NASA Astrophysics Data System (ADS)

    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.

  12. Low-cost multi-vehicle air temperature measurements for heat load assessment in local-scale climate applications

    NASA Astrophysics Data System (ADS)

    Zuvela-Aloise, Maja; Weyss, Gernot; Aloise, Giulliano; Mifka, Boris; Löffelmann, Philemon; Hollosi, Brigitta; Nemec, Johana; Vucetic, Visnja

    2014-05-01

    In the recent years there has been a strong interest in exploring the potential of low-cost measurement devices as alternative source of meteorological monitoring data, especially in the urban areas where high-density observations become crucial for appropriate heat load assessment. One of the simple, but efficient approaches for gathering large amount of spatial data is through mobile measurement campaigns in which the sensors are attached to driving vehicles. However, non-standardized data collecting procedure, instrument quality, their response-time and design, variable device ventilation and radiation protection influence the reliability of the gathered data. We investigate what accuracy can be expected from the data collected through low-cost mobile measurements and whether the achieved quality of the data is sufficient for validation of the state-of-the-art local-scale climate models. We tested 5 types of temperature sensors and data loggers: Maxim iButton, Lascar EL-USB-2-LCD+ and Onset HOBO UX100-003 as market available devices and self-designed solar powered Arduino-based data loggers combined with the AOSONG AM2315 and Sensirion SHT21 temperature and humidity sensors. The devices were calibrated and tested in stationary mode at the Austrian Weather Service showing accuracy between 0.1°C and 0.8°C, which was mostly within the device specification range. In mobile mode, the best response-time was found for self-designed device with Arduino-based data logger and Sensirion SHT21 sensor. However, the device lacks the mechanical robustness and should be further improved for broad-range applications. We organized 4 measurement tours: two taking place in urban environment (Vienna, Austria in July 2011 and July 2013) and two in countryside with complex terrain of Mid-Adriatic islands (Hvar and Korcula, Croatia in August 2013). Measurements were taken on clear-sky, dry and hot days. We combined multiple devices attached to bicycle and cars with different

  13. 3. BUILDING 8814, WEST SIDE AND SOUTH REAR, SHOWING BLAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. BUILDING 8814, WEST SIDE AND SOUTH REAR, SHOWING BLAST DOOR. BUILDING 8826 IS IN BACKGROUND. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunker 1-D-3, Test Area 1-125, northwest end of Altair Boulevard, Boron, Kern County, CA

  14. Final Report Recommended Actions to Reduce Electrical Peak Loads at the Marine Corps Air Station at Camp Pendleton, California

    SciTech Connect

    Hail, John C.; Brown, Daryl R.; McCullough, Jeffrey J.; Underhill, Ronald M.

    2001-05-08

    PNNL conducted a walk-through audit of Marine Corps Air Station at Camp Pendleton. The audit inspected a significant portion of the site and identified a large number of similar energy saving opportunities across all building types.

  15. Blast injury research models

    PubMed Central

    Kirkman, E.; Watts, S.; Cooper, G.

    2011-01-01

    Blast injuries are an increasing problem in both military and civilian practice. Primary blast injury to the lungs (blast lung) is found in a clinically significant proportion of casualties from explosions even in an open environment, and in a high proportion of severely injured casualties following explosions in confined spaces. Blast casualties also commonly suffer secondary and tertiary blast injuries resulting in significant blood loss. The presence of hypoxaemia owing to blast lung complicates the process of fluid resuscitation. Consequently, prolonged hypotensive resuscitation was found to be incompatible with survival after combined blast lung and haemorrhage. This article describes studies addressing new forward resuscitation strategies involving a hybrid blood pressure profile (initially hypotensive followed later by normotensive resuscitation) and the use of supplemental oxygen to increase survival and reduce physiological deterioration during prolonged resuscitation. Surprisingly, hypertonic saline dextran was found to be inferior to normal saline after combined blast injury and haemorrhage. New strategies have therefore been developed to address the needs of blast-injured casualties and are likely to be particularly useful under circumstances of enforced delayed evacuation to surgical care. PMID:21149352

  16. General view of blast furnace plant, with blast furnace "A" ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of blast furnace plant, with blast furnace "A" (built in 1907) to the left; in the foreground is the turbo-blower and blast furnace gas-powered electric generating station (built in 1919), looking northwest - Bethlehem Steel Corporation, South Bethlehem Works, Blast Furnace "A", Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

  17. Ground crewmen prepare to load the crated SOFIA primary mirror assembly into an Air Force C-17 for shipment to NASA Ames Research Center for finish coating

    NASA Image and Video Library

    2008-05-01

    Technicians at NASA's Dryden Aircraft Operations Facility in Palmdale, Calif., loaded the German-built primary mirror assembly of the Stratospheric Observatory for Infrared Astronomy, or SOFIA, onto an Air Force C-17 for shipment to NASA's Ames Research Center on May 1, 2008. In preparation for the final finish coating of the mirror, the more than two-ton mirror assembly had been removed from its cavity in the rear fuselage of the highly modified SOFIA Boeing 747SP two weeks earlier. After arrival at NASA Ames at Moffett Field near Mountain View, Calif., the mirror would receive its aluminized finish coating before being re-installed in the SOFIA aircraft.

  18. Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001(PNW2001) Air Quality Study In Puget Sound

    NASA Astrophysics Data System (ADS)

    Disselkamp, R. S.; Barrie, L. A.; Shutthanadan, S.; Cliff, S.; Cahill, T.

    2001-12-01

    In mid-August, 2001, an aircraft-based air-quality study was performed in the Puget Sound, WA, area entitled PNW2001 (http://www.pnl.gov/pnw2001). The objectives of this field campaign were the following: 1. reveal information about the 3-dimensional distribution of ozone, its gaseous precursors and fine particulate matter during weather conditions favoring air pollution; 2. derive information about the accuracy of urban and biogenic emissions inventories that are used to drive the air quality forecast models; and 3. examine the accuracy of modeled ozone concentration with that observed. In support of these efforts, we collected time-averaged ( { ~}10 minute averages), size-segregated, aerosol composition and mass-loading information using ex post facto analysis techniques of synchrotron x-ray fluorescence (s-XRF), proton induced x-ray emissions(PIXE), proton elastic scattering (PESA), and scanning transmission ion microscopy (STIM). This is the first time these analysis techniques have been used together on samples collected from aircraft using an optimized 3-stage rotating drum impactor. In our presentation, we will discuss the aerosol components in three aerosol size fractions as identified by statistical analysis of multielemental data (including total mass, H, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Pb) and relate variations in these components to physical aerosol properties, other gaseous trace constituents and to air mass origin.

  19. Simulations of Porcine Eye Exposure to Primary Blast Insult

    PubMed Central

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

    2015-01-01

    Purpose A computational model of the porcine eye was developed to simulate primary blast exposure. This model facilitates understanding of blast-induced injury mechanisms. Methods 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. Results 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. Conclusions 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. Translational Relevance 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. PMID:26336633

  20. Primary blast injury causes cognitive impairments and hippocampal circuit alterations.

    PubMed

    Beamer, Matthew; Tummala, Shanti R; Gullotti, David; Kopil, Catherine; Gorka, Samuel; Ted Abel; Bass, Cameron R Dale; Morrison, Barclay; Cohen, Akiva S; Meaney, David F

    2016-09-01

    Blast-induced traumatic brain injury (bTBI) and its long term consequences are a major health concern among veterans. Despite recent work enhancing our knowledge about bTBI, very little is known about the contribution of the blast wave alone to the observed sequelae. Herein, we isolated its contribution in a mouse model by constraining the animals' heads during exposure to a shockwave (primary blast). Our results show that exposure to primary blast alone results in changes in hippocampus-dependent behaviors that correspond with electrophysiological changes in area CA1 and are accompanied by reactive gliosis. Specifically, five days after exposure, behavior in an open field and performance in a spatial object recognition (SOR) task were significantly different from sham. Network electrophysiology, also performed five days after injury, demonstrated a significant decrease in excitability and increase in inhibitory tone. Immunohistochemistry for GFAP and Iba1 performed ten days after injury showed a significant increase in staining. Interestingly, a threefold increase in the impulse of the primary blast wave did not exacerbate these measures. However, we observed a significant reduction in the contribution of the NMDA receptors to the field EPSP at the highest blast exposure level. Our results emphasize the need to account for the effects of primary blast loading when studying the sequelae of bTBI.

  1. Primary blast injury causes cognitive impairments and hippocampal circuit alterations

    PubMed Central

    Beamer, Matthew; Tummala, Shanti R.; Gullotti, David; Kopil, Kathryn; Gorka, Samuel; Abel, Ted; “Dale” Bass, Cameron R.; Morrison, Barclay; Cohen, Akiva S.; Meaney, David F.

    2016-01-01

    Blast-induced traumatic brain injury (bTBI) and its long term consequences are a major health concern among veterans. Despite recent work enhancing our knowledge about bTBI, very little is known about the contribution of the blast wave alone to the observed sequelae. Herein, we isolated its contribution in a mouse model by constraining the animals' heads during exposure to a shockwave (primary blast). Our results show that exposure to primary blast alone results in changes in hippocampus-dependent behaviors that correspond with electro-physiological changes in area CA1 and are accompanied by reactive gliosis. Specifically, five days after exposure, behavior in an open field and performance in a spatial object recognition (SOR) task were significantly different from sham. Network electrophysiology, also performed five days after injury, demonstrated a significant decrease in excitability and increase in inhibitory tone. Immunohistochemistry for GFAP and Iba1 performed ten days after injury showed a significant increase in staining. Interestingly, a threefold increase in the impulse of the primary blast wave did not exacerbate these measures. However, we observed a significant reduction in the contribution of the NMDA receptors to the field EPSP at the highest blast exposure level. Our results emphasize the need to account for the effects of primary blast loading when studying the sequelae of bTBI. PMID:27246999

  2. A Study on the Vibration Frequency of Blasting Excavation in Highly Stressed Rock Masses

    NASA Astrophysics Data System (ADS)

    Yang, Jianhua; Lu, Wenbo; Jiang, Qinghui; Yao, Chi; Jiang, Shuihua; Tian, Lin

    2016-07-01

    During blasting excavation in deep-buried tunnels and mines characterized by high in situ stress, the rock vibration is attributed not only to blast loading, but also to dynamic unloading caused by transient release of the in situ stress on excavation faces in the process of rock fragmentation by blasting. Understanding the vibration frequency characteristics under these two excitation sources is of important signification to determine appropriate vibration threshold limits for structure damage in deep-buried opening excavations. With a theoretical model developed for a deep-buried circular tunnel excavation by the millisecond delay blasting sequence, frequency characteristics and their influence factors are investigated and discussed for the vibrations induced by the blast loading, the dynamic unloading and the combined effects, respectively. The results show that the rising time of blast loading, the duration of dynamic unloading and the dimension of excavation boundaries are the main factors that affect the vibration frequency of blasting excavation in highly stressed rock masses. It is found that, the blast loading with a much shorter rising time accentuates higher vibration frequency than the dynamic unloading with a long duration, and it causes the blast loading vibration to be more readily attenuated as the propagation distance increases. Thus, the unloading vibration may become the main vibration component at far distances where its low-frequency vibration may exceed the vibration limits. The vibration induced by the combined effects has two distinctly dominant frequency bands corresponding to the two vibration excitation sources. The frequency analyses of the vibration records from two underground projects excavated by blasting are presented to demonstrate this finding. The findings of this study also clearly reveal that, reducing the dimension of excavation boundaries is one of the most effective means to prevent the vibrational damage to structures as it

  3. Face Sheet/Core Disbond Growth in Honeycomb Sandwich Panels Subjected to Ground-Air-Ground Pressurization and In-Plane Loading

    NASA Technical Reports Server (NTRS)

    Chen, Zhi M.; Krueger, Ronald; Rinker, Martin

    2015-01-01

    Typical damage modes in light honeycomb sandwich structures include face sheet/core disbonding and core fracture, both of which can pose a threat to the structural integrity of a component. These damage modes are of particular interest to aviation certification authorities since several in-service occurrences, such as rudder structural failure and other control surface malfunctions, have been attributed to face sheet/core disbonding. Extensive studies have shown that face sheet/core disbonding and core fracture can lead to damage propagation caused by internal pressure changes in the core. The increasing use of composite sandwich construction in aircraft applications makes it vitally important to understand the effect of ground-air-ground (GAG) cycles and conditions such as maneuver and gust loads on face sheet/core disbonding. The objective of the present study was to use a fracture mechanics based approach developed earlier to evaluate the loading at the disbond front caused by ground-air-ground pressurization and in-plane loading. A honeycomb sandwich panel containing a circular disbond at one face sheet/core interface was modeled with three-dimensional (3D) solid finite elements. The disbond was modeled as a discrete discontinuity and the strain energy release rate along the disbond front was computed using the Virtual Crack Closure Technique (VCCT). Special attention was paid to the pressure-deformation coupling which can decrease the pressure load within the disbonded sandwich section significantly when the structure is highly deformed. The commercial finite element analysis software, Abaqus/Standard, was used for the analyses. The recursive pressure-deformation coupling problem was solved by representing the entrapped air in the honeycomb cells as filled cavities in Abaqus/Standard. The results show that disbond size, face sheet thickness and core thickness are important parameters that determine crack tip loading at the disbond front. Further, the pressure

  4. An animal-to-human scaling law for blast-induced traumatic brain injury risk assessment.

    PubMed

    Jean, Aurélie; Nyein, Michelle K; Zheng, James Q; Moore, David F; Joannopoulos, John D; Radovitzky, Raúl

    2014-10-28

    Despite recent efforts to understand blast effects on the human brain, there are still no widely accepted injury criteria for humans. Recent animal studies have resulted in important advances in the understanding of brain injury due to intense dynamic loads. However, the applicability of animal brain injury results to humans remains uncertain. Here, we use advanced computational models to derive a scaling law relating blast wave intensity to the mechanical response of brain tissue across species. Detailed simulations of blast effects on the brain are conducted for different mammals using image-based biofidelic models. The intensity of the stress waves computed for different external blast conditions is compared across species. It is found that mass scaling, which successfully estimates blast tolerance of the thorax, fails to capture the brain mechanical response to blast across mammals. Instead, we show that an appropriate scaling variable must account for the mass of protective tissues relative to the brain, as well as their acoustic impedance. Peak stresses transmitted to the brain tissue by the blast are then shown to be a power function of the scaling parameter for a range of blast conditions relevant to TBI. In particular, it is found that human brain vulnerability to blast is higher than for any other mammalian species, which is in distinct contrast to previously proposed scaling laws based on body or brain mass. An application of the scaling law to recent experiments on rabbits furnishes the first physics-based injury estimate for blast-induced TBI in humans.

  5. Monte Carlo simulation as a tool to predict blasting fragmentation based on the Kuz Ram model

    NASA Astrophysics Data System (ADS)

    Morin, Mario A.; Ficarazzo, Francesco

    2006-04-01

    Rock fragmentation is considered the most important aspect of production blasting because of its direct effects on the costs of drilling and blasting and on the economics of the subsequent operations of loading, hauling and crushing. Over the past three decades, significant progress has been made in the development of new technologies for blasting applications. These technologies include increasingly sophisticated computer models for blast design and blast performance prediction. Rock fragmentation depends on many variables such as rock mass properties, site geology, in situ fracturing and blasting parameters and as such has no complete theoretical solution for its prediction. However, empirical models for the estimation of size distribution of rock fragments have been developed. In this study, a blast fragmentation Monte Carlo-based simulator, based on the Kuz-Ram fragmentation model, has been developed to predict the entire fragmentation size distribution, taking into account intact and joints rock properties, the type and properties of explosives and the drilling pattern. Results produced by this simulator were quite favorable when compared with real fragmentation data obtained from a blast quarry. It is anticipated that the use of Monte Carlo simulation will increase our understanding of the effects of rock mass and explosive properties on the rock fragmentation by blasting, as well as increase our confidence in these empirical models. This understanding will translate into improvements in blasting operations, its corresponding costs and the overall economics of open pit mines and rock quarries.

  6. Effect of air-particle abrasion protocols on the biaxial flexural strength, surface characteristics and phase transformation of zirconia after cyclic loading.

    PubMed

    Ozcan, Mutlu; Melo, Renata M; Souza, Rodrigo O A; Machado, João P B; Felipe Valandro, Luiz; Botttino, Marco A

    2013-04-01

    This study evaluated the effect of air-particle abrasion protocols on the biaxial flexural strength, surface characteristics and phase transformation of zirconia after cyclic loading. Disc-shaped zirconia specimens (Ø: 15mm, thickness: 1.2mm) (N=32) were submitted to one of the air-particle abrasion protocols (n=8 per group): (a) 50μm Al2O3 particles, (b) 110μm Al2O3 particles coated with silica (Rocatec Plus), (c) 30μm Al2O3 particles coated with silica (CoJet Sand) for 20s at 2.8bar pressure. Control group received no air-abrasion. All specimens were initially cyclic loaded (×20,000, 50N, 1Hz) in water at 37°C and then subjected to biaxial flexural strength testing where the conditioned surface was under tension. Zirconia surfaces were characterized and roughness was measured with 3D surface profilometer. Phase transformation from tetragonal to monoclinic was determined by Raman spectroscopy. The relative amount of transformed monoclinic zirconia (FM) and transformed zone depth (TZD) were measured using XRD. The data (MPa) were analyzed using ANOVA, Tukey's tests and Weibull modulus (m) were calculated for each group (95% CI). The biaxial flexural strength (MPa) of CoJet treated group (1266.3±158(A)) was not significantly different than that of Rocatec Plus group (1179±216.4(A,B)) but was significantly higher than the other groups (Control: 942.3±74.6(C); 50μm Al2O3: 915.2±185.7(B,C)). Weibull modulus was higher for control (m=13.79) than those of other groups (m=4.95, m=5.64, m=9.13 for group a, b and c, respectively). Surface roughness (Ra) was the highest with 50μm Al2O3 (0.261μm) than those of other groups (0.15-0.195μm). After all air-abrasion protocols, FM increased (15.02%-19.25%) compared to control group (11.12%). TZD also showed increase after air-abrasion protocols (0.83-1.07μm) compared to control group (0.59μm). Air-abrasion protocols increased the roughness and monoclinic phase but in turn abrasion with 30μm Al2O3 particles coated

  7. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes... outage scale visible through the manway opening shall be provided. If loading devices are applied to...

  8. Spectrum of abdominal organ injury in a primary blast type

    PubMed Central

    2009-01-01

    Introduction Abdominal organ injury in a primary blast type is always challenging for diagnosis. Air containing abdominal viscera is most vulnerable to effects of primary blast injury. In any patient exposed to a primary blast wave who presents with an acute abdomen, an abdominal organ injury is to be kept in a clinical suspicion. Aim Study various abdominal organ injuries occurring in a primary type of blast injury. Material and methods: All those who had exploratory laparotomy for abdominal organ injuries after a primary blast injury for a period of 10 years from January 1998 - January 2008 were included in this retrospective study. Results Total 154 patients had laparotomy for abdominal organ injuries with a primary blast type of injury. Small intestine was damaged in 48 patients (31.1%) followed by spleen in 22.7% cases. 54 patients (35.06%) had more than one organ injured. Liver laceration was present in 30 patients (19.48%). Multiple small gut perforations were present in 37 patients (77.08%). Negative laparotomy was found in 5 patients (3.24%) whereas 3 (1.94%) had re-exploration. Mortality was present in 6 patients (3.89%). Conclusions Primary blast injury causes varied abdominal organ injuries. Single or multiple organ damage can be there. Small intestine is commonest viscera injured. Laparotomy gives final diagnosis. PMID:20025766

  9. Comparison of three distinct clean air suits to decrease the bacterial load in the operating room: an observational study.

    PubMed

    Kasina, Piotr; Tammelin, Ann; Blomfeldt, Anne-Marie; Ljungqvist, Bengt; Reinmüller, Berit; Ottosson, Carin

    2016-01-01

    Lowering air-borne bacteria counts in the operating room is essential in prevention of surgical site infections in orthopaedic joint replacement surgery. This is mainly achieved by decreasing bacteria counts through dilution, with appropriate ventilation and by limiting the bacteria carrying skin particles, predominantly shed by the personnel. The aim of this study was to investigate if a single use polypropylene clothing system or a reusable polyester clothing system could offer similar air quality in the operating room as a mobile laminar airflow device-assisted reusable cotton/polyester clothing system. Prospective observational study design, comparing the performance of three Clean Air Suits by measuring Colony Forming Units (CFU)/m(3) of air during elective hip and knee arthroplasties, performed at a large university-affiliated hospital. The amount of CFU/m(3) of air was measured during 37 operations of which 13 were performed with staff dressed in scrub suits made of a reusable mixed material (69 % cotton, 30 % polyester, 1 % carbon fibre) accompanied by two mobile laminar airflow units. During 24 procedures no mobile laminar airflow units were used, 13 with staff using a reusable olefin fabric clothing (woven polypropylene) and 11 with staff dressed in single-use suits (non-woven spunbonded polypropylene). Air from the operating field was sampled through a filter, by a Sartorius MD8, and bacterial colonies were counted after incubation. There were 6-8 measurements from each procedure, in total 244 measurements. Statistical analysis was performed by Mann-Whitney U-test. The single-use polypropylene suit reduced the amount of CFU/m(3) to a significantly lower level than both other clothing systems. Single-use polypropylene clothing systems can replace mobile laminar airflow unit-assisted reusable mixed material-clothing systems. Measurements in standardized laboratory settings can only serve as guidelines as environments in real operation settings present a

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Lightweight blast shield

    DOEpatents

    Mixon, Larry C.; Snyder, George W.; Hill, Scott D.; Johnson, Gregory L.; Wlodarski, J. Frank; von Spakovsky, Alexis P.; Emerson, John D.; Cole, James M.; Tipton, John P.

    1991-01-01

    A tandem warhead missile arrangement that has a composite material housing structure with a first warhead mounted at one end and a second warhead mounted near another end of the composite structure with a dome shaped composite material blast shield mounted between the warheads to protect the second warhead from the blast of the first warhead.

  12. Mine Blast Loading: Experiments and Simulations

    DTIC Science & Technology

    2010-04-01

    EOS sesame tables for soil from the mixture of solid grains and varying amounts of water (4%-24%). The EOS numbers, percentage moisture, initial...equation of state ( EOS ) developed by Kerley. The EOS explicitly accounts for soil moisture content and initial distension (porosity). It was found that...33 4.2.1 Review of Sand EOS in CTH ........................................................................ 33 4.2.2

  13. Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

    SciTech Connect

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

    2011-01-21

    that the headform locally experiences a nearly planar blast wave. Also, the positive phase durations and blast impulses are much larger than those of (1). Consequently, the blast model used in (1) is spatially and temporally very different from a military blast. It would be useful to repeat the calculations using military blast parameters. Finally, (1) overlooks a significant part of (5). On page 1 and on page 3, (1) states that (5) did not consider helmet pads. But pages pages 3 and 4 of (5) present simulations of blast wave propagation across an ACH helmeted head form with and without pads. (5) states that when the pads are present, the 'underwash' of air under the helmet is blocked when compared to the case without. (1) reaches this same conclusion, but reports it as a new result rather than a confirmation of that already found in (5).

  14. Fragmentation, Cost and Environmental Effects of Plaster Stemming Method for Blasting at A Basalt Quarry

    NASA Astrophysics Data System (ADS)

    Cevizci, Halim

    2014-10-01

    In this study, the plaster stemming application for blasting at a basalt quarry is studied. Drill cuttings are generally used in open pits and quarries as the most common stemming material since these are most readily available at blast sites. However, dry drill cuttings eject very easily from blastholes without offering much resistance to blast energy. The plaster stemming method has been found to be better than the drill cuttings stemming method due to increased confinement inside the hole and better utilization of blast explosive energy in the rock. The main advantage of the new stemming method is the reduction in the cost of blasting. At a basalt quarry, blasting costs per unit volume of rock were reduced to 15% by increasing burden and spacing distances. In addition, better fragmentation was obtained by using the plaster stemming method. Blast trials showed that plaster stemming produced finer material. In the same blast tests, +30 cm size fragments were reduced to 47.3% of the total, compared to 32.6% in the conventional method of drill cuttings stemming. With this method of stemming, vibration and air shock values increased slightly due to more blast energy being available for rock breakage but generally these increased values were small and stayed under the permitted limit for blast damage criteria unless measuring distance is too close.

  15. Full-scale Blast Test Response of Partially Grouted Masonry Walls

    DTIC Science & Technology

    2011-01-01

    walls , precast /prestressed panels, tilt-up panels, masonry components, autoclaved concrete components, cast-in-place forming systems, etc...program focused on the blast impulse load response of partially grouted concrete masonry unit (CMU) walls that minimally comply with the standards of...component of the program focused on the blast impulse load response of partially grouted concrete masonry unit (CMU) walls that minimally comply with the

  16. An Accumulated Damage Model for Blast Propagation in Compartmented Structures with Progressively Failing Thin Bulkheads

    DTIC Science & Technology

    2009-12-01

    freedom models subjected to blast loading, Intern. J. Impact Engng 34(4), 823–842. Gelfand, B. E. & Silnikov , M. V . (2004) Explosions and Blast...models for weapon–target interaction. v DSTO–TR–2365 vi DSTO–TR–2365 Contents 1 Introduction 1 2 Mathematical model 2 3 Numerical algorithm 5 4...loading scenarios [Baker 1973, Baker et al. 1983, Lloyd 1998, Gelfand & Silnikov 2004, Fallah & Louca 2007]. It is assumed that the time history of the

  17. A Conformal, Fully-Conservative Approach for Predicting Blast Effects on Ground Vehicles

    DTIC Science & Technology

    2014-04-01

    Fluid-Structure Interaction (FSI) simulations ◦ Conservative load transfer between Loci/ BLAST and LS - DYNA ◦ Robust deformation of CFD mesh in response...impulse pendulum results UNCLASSIFIED UNCLASSIFIED  Loci/ BLAST - LS - DYNA two-way coupling validated using DRDC Plate experiment ◦ DRDC plate deflections...compared to results of Williams et al (7th International LS - DYNA Users Conference, 2002) for TACOM Impulse Loading model (Westline, 1972)  TARDEC

  18. Normal impingement loads due to small air jets issuing from a base plate and reflecting off a platform for various jet Mach numbers, separation distances, and ambient pressures

    NASA Technical Reports Server (NTRS)

    Hoffman, S.

    1972-01-01

    An investigation was conducted in a 12.5-meter-diameter vacuum sphere to determine the impingement loads due to air jets issuing from and perpendicular to a circular base and reflecting off a square platform, that is, a simulation of rendezvous maneuvering, docking, launch, impact dampers etc. The nozzles had exit Mach numbers of 1, 3, 5, and 7. The ambient pressures were 0.0006, 5, 225, and 760 torr. Under near-field separation distances and at 0.0006 torr, reflections were significant; and ratios of the impingement force to thrust on both plates in the biplane arrangement varied from about 750 for exit Mach number 1 to 120 for exit Mach number 7. The far-field force ratios were near unity for the platform and zero for the base and indicated few, if any, reflections. Some reversals and rapid changes in loads were obtained at transition distances between the near and far fields. In general, increasing the exit Mach number or ambient pressure reduced the impingement loads.

  19. Air atmospheric pressure plasma jet pretreatment for drop-wise loading of dexamethasone on hydroxyapatite scaffold for increase of osteoblast attachment.

    PubMed

    Lee, Jung-Hwan; Kwon, Jae-Sung; Kim, Yong Hee; Choi, Eun Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-10-01

    Periodontal disease affects alveolar bone resorption around the involved teeth. To gain bone height, bone graft materials have been widely used with drug carriers. Application of an atmospheric pressure plasma jet (APPJ) treatment is widely studied due to its ability to change surface characteristics without topographical change. The aim of this study is to identify whether the air APPJ (AAPPJ) treatment before drop-wise loading performance could change loaded amount of dexamethasone, and induce increase of cell attachment and proliferation. The results suggested that AAPPJ treatment decreased the contact angle down to about 13 degrees, which increased gradually but significantly lowered at least 4 days compared to no-treated group. After AAPPJ treatment, hydrocarbon was removed with change of zeta potential into positive charge. However, the AAPPJ treatment did not change the quantity or releasing profile of dexamethasone (p > 0.05). Confocal analysis combined with DNA proliferation analysis showed increase of osteoblast attachment and proliferation. Hence, AAPPJ could be a useful pretreatment method before drop-wise loading on HA scaffold with dexamethasone for increase of osteoblast attachment.

  20. Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters

    SciTech Connect

    Smith, Brian M.; Barnett, J. Matthew; Ballinger, Marcel Y.

    2011-01-18

    This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

  1. Explosive signatures: Pre & post blast

    NASA Astrophysics Data System (ADS)

    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

  2. Air-loads Prediction of a UH-60A Rotor Inside the 40- by 80-Foot Wind Tunnel

    DTIC Science & Technology

    2010-01-22

    schemes allow a bigger time step for numerical stability. Viscous flow boundary conditions with the Spalart - Allmaras turbulence model are used in...free-air flight case. One possible reason for the failed convergence could be that the Spalart - Allmaras turbulence model is used, instead of the...Baldwin-Barth turbulence model, in the present calculations. The Baldwin- Barth turbulence model was applied in the previous work and did yield

  3. Evaluating the Efficiency of Air Shower in Removing Lead from Army Combat Uniform Swatches Loaded with Gunshot Residue

    DTIC Science & Technology

    2016-03-25

    and its components with soap and water and dried it with paper towels . The investigators then re-assembled the test assembly, attached the chamber...solution (Hygenall Corp., Huntsville, AL) and dried with paper towels . The investigators then re-assembled the chamber with a blank swatch, attached the...academia. Several articles and white papers have been published on this subject leading to “Great Air Shower Debate” session during the CLEANROOMS’95

  4. Operation Greenhouse. Scientific Director's report. Annex 1. 6. Blast measurements. Part 2. Free-air peak-pressure measurements. Section 1. Nuclear explosions, 1951

    SciTech Connect

    Moulton, J.F.; Simonds, B.T.

    1984-10-31

    The primary objective of this experiment was to obtain accurate information on the pressure in the shock wave in the free-air region. In particular, it was desired to know the peak pressure as a function of distance in this region. Secondary objectives were to determine the path of the triple point and to determine the peak pressure in the Mach-stem region.

  5. Compressed air blast injury with palpebral, orbital, facial, cervical, and mediastinal emphysema through an eyelid laceration: a case report and review of literature

    PubMed Central

    2013-01-01

    Background To the best of our knowledge, only 14 cases of orbital or periorbital compressed air injuries from air guns or hoses have been reported in the literature. Case presentation A 30-year-old man was accidentally injured when a compressed air hose nozzle hit his right eye. The right half of his face was markedly swollen and a skin laceration near the right medial canthus was identified. A computed tomography scan showed subcutaneous and intraorbital emphysema around the right eye as well as cervical and mediastinal emphysema. He was prophylactically treated with systemic and topical antibiotics to prevent infection. All emphysemas had completely resolved 2 weeks after the injury. Conclusions A review of all 15 cases (including ours) showed that all patients were male and that 6 of the 15 (40.0%) cases were related to industrial accidents. Although emphysema was restricted to the subconjunctival space in 2 (13.3%) cases, it spread to the orbit in the remaining 13 (86.7%) cases. Cervical and mediastinal emphysemas were found in 3 (20.0%) cases, and intracranial emphysema was confirmed in 6 (40.0%) cases. Prophylactic antibiotics were used in most cases and the prognosis was generally good in all but one patient, who developed optic atrophy and blindness. PMID:24195485

  6. Carbon monoxide exposure in blast furnace workers.

    PubMed

    Lewis, S; Mason, C; Srna, J

    1992-09-01

    This study investigated the occupational exposure to carbon monoxide (CO) of a group of blast furnace workers from an integrated steelworks, compared to a control group having no significant occupational CO exposure from other areas in the same works. The study was undertaken in 1984 at Port Kembla, New South Wales. Carboxyhaemoglobin (COHb) levels before and after an eight-hour work shift were measured in 98 male steelworkers: 52 from two CO-exposed iron blast furnaces and 46 controls from production areas in the same steelworks. The sample was stratified by smoking habits. Environmental air CO levels had been found to be consistently higher on one furnace than on the other. Absorption of CO from the working environment occurred in workers on the blast furnace with higher CO levels, regardless of smoking habits. On this blast furnace, some readings of COHb levels after a workshift in nonsmokers approached the proposed Australian occupational limit of 5 per cent COHb saturation. Overall, workers with the highest occupational exposure who smoked most heavily had the highest absorption of CO over a work shift. Biological monitoring gives an accurate measure of individual worker 'dose' of CO from all sources. Both environmental monitoring and biological monitoring need to be included as part of a program for controlling occupational CO exposure.

  7. Blast wave mitigation by dry aqueous foams

    NASA Astrophysics Data System (ADS)

    Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

    2013-02-01

    This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

  8. Passive blast pressure sensor

    DOEpatents

    King, Michael J.; Sanchez, Roberto J.; Moss, William C.

    2013-03-19

    A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

  9. Air-particle abrasion on zirconia ceramic using different protocols: effects on biaxial flexural strength after cyclic loading, phase transformation and surface topography.

    PubMed

    Souza, Rodrigo O A; Valandro, Luiz F; Melo, Renata M; Machado, João P B; Bottino, Marco A; Ozcan, Mutlu

    2013-10-01

    This study evaluated the effect of different air-particle abrasion protocols on the biaxial flexural strength and structural stability of zirconia ceramics. Zirconia ceramic specimens (ISO 6872) (Lava, 3M ESPE) were obtained (N=336). The specimens (N=118, n=20 per group) were randomly assigned to one of the air-abrasion protocols: Gr1: Control (as-sintered); Gr2: 50 µm Al2O3 (2.5 bar); Gr3: 50 µm Al2O3 (3.5 bar); Gr4: 110 µm Al2O3(2.5 bar); Gr5: 110 µm Al2O3 (3.5 bar); Gr6: 30 µm SiO2 (2.5 bar) (CoJet); Gr7: 30 µm SiO2(3.5 bar); Gr8: 110 µm SiO2 (2.5 bar) (Rocatec Plus); and Gr9: 110 µm SiO2 (3.5 bar) (duration: 20 s, distance: 10 mm). While half of the specimens were tested immediately, the other half was subjected to cyclic loading in water (100,000 cycles; 50 N, 4 Hz, 37 °°C) prior to biaxial flexural strength test (ISO 6872). Phase transformation (t→m), relative amount of transformed monoclinic zirconia (FM), transformed zone depth (TZD) and surface roughness were measured. Particle type (p=0.2746), pressure (p=0.5084) and cyclic loading (p=0.1610) did not influence the flexural strength. Except for the air-abraded group with 110 µm Al2O3 at 3.5 bar, all air-abrasion protocols increased the biaxial flexural strength (MPa) (Controlnon-aged: 1,030 ± 153, Controlaged: 1,138 ± 138; Experimentalnon-aged: 1,307 ± 184-1,554 ± 124; Experimentalaged: 1,308 ± 118-1,451 ± 135) in both non-aged and aged conditions, respectively. Surface roughness (Ra) was the highest with 110 µm Al2O3(0.84 µm. FM values ranged from 0% to 27.21%, higher value for the Rocatec Plus (110 µm SiO2) and 110 µm Al2O3 groups at 3.5 bar pressure. TZD ranged between 0 and 1.43 µm, with the highest values for Rocatec Plus and 110 µm Al2O3 groups at 3.5 bar pressure. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Technology Solutions Case Study: Air-To-Water Heat Pumps with Radiant Delivery in Low Load Homes, Tucson, Arizona and Chico, California

    SciTech Connect

    2013-11-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  11. Investigation of blast-induced traumatic brain injury

    PubMed Central

    Ludwigsen, John S.; Ford, Corey C.

    2014-01-01

    Objective Many troops deployed in Iraq and Afghanistan have sustained blast-related, closed-head injuries from being within non-lethal distance of detonated explosive devices. Little is known, however, about the mechanisms associated with blast exposure that give rise to traumatic brain injury (TBI). This study attempts to identify the precise conditions of focused stress wave energy within the brain, resulting from blast exposure, which will correlate with a threshold for persistent brain injury. Methods This study developed and validated a set of modelling tools to simulate blast loading to the human head. Using these tools, the blast-induced, early-time intracranial wave motions that lead to focal brain damage were simulated. Results The simulations predict the deposition of three distinct wave energy components, two of which can be related to injury-inducing mechanisms, namely cavitation and shear. Furthermore, the results suggest that the spatial distributions of these damaging energy components are independent of blast direction. Conclusions The predictions reported herein will simplify efforts to correlate simulation predictions with clinical measures of TBI and aid in the development of protective headwear. PMID:24766453

  12. Comparison of methods for the analysis of airway macrophage particulate load from induced sputum, a potential biomarker of air pollution exposure.

    PubMed

    Jary, Hannah; Rylance, Jamie; Patel, Latifa; Gordon, Stephen B; Mortimer, Kevin

    2015-11-05

    Air pollution is associated with a high burden or morbidity and mortality, but exposure cannot be quantified rapidly or cheaply. The particulate burden of macrophages from induced sputum may provide a biomarker. We compare the feasibility of two methods for digital quantification of airway macrophage particulate load. Induced sputum samples were processed and analysed using ImageJ and Image SXM software packages. We compare each package by resources and time required. 13 adequate samples were obtained from 21 patients. Median particulate load was 0.38 μm(2) (ImageJ) and 4.0 % of the total cellular area of macrophages (Image SXM), with no correlation between results obtained using the two methods (correlation coefficient = -0.42, p = 0.256). Image SXM took longer than ImageJ (median 26 vs 54 mins per participant, p = 0.008) and was less accurate based on visual assessment of the output images. ImageJ's method is subjective and requires well-trained staff. Induced sputum has limited application as a screening tool due to the resources required. Limitations of both methods compared here were found: the heterogeneity of induced sputum appearances makes automated image analysis challenging. Further work should refine methodologies and assess inter- and intra-observer reliability, if these methods are to be developed for investigating the relationship of particulate and inflammatory response in the macrophage.

  13. Development of a structurally integrated conformal load-bearing multifunction antenna: overview of the Air Force Smart Skin Structures Technology Demonstration Program

    NASA Astrophysics Data System (ADS)

    Lockyer, Allen J.; Alt, Kevin H.; Kinslow, Robert W.; Kan, Han-Pin; Kudva, Jayanth N.; Tuss, James; Goetz, Allan C.

    1996-05-01

    The Structures Division of the Air Force's Wright Laboratory is sponsoring the development and demonstration of a new high pay-off technology termed CLAS--Conformal Load Bearing Antenna Structures. Northrop Grumman Corporation and TRW/ASD are developing the technology under the `Smart-Skin Structure Technology Demonstration (S3D)' program, contract, No. F33615-93-C-3200. The program goal is to design, develop, fabricate, and test a CLAS component and lay the foundation for future work where potential benefits from structurally integrated antennas may be realized. Key issues will focus but are not limited to the design, structures, and manufacturing aspects of antenna embedment into load bearing aircraft structures. Results from Phase I of the program have been previously reported, where initial pay-offs in reducing overall airframe acquisition and support cost, weight, signature, and drag were quantitatively and qualitatively identified. A full-sized CLAS component, featuring a broadband multi-arm spiral embedded in sandwich stiffened structure, will be fabricated and tested for static strength, durability, and damage tolerance. Basic electrical performance, (e.g. radiation patterns, gain, and impedance) will also be verified; however, extensive electrical validation will be the subject of further work. Key aspects of the work and progress to date are detailed below.

  14. Structural finite-element modeling strategies for conformal load-bearing antenna structure (CLAS) (Air Force contract F33615-C-93-3200)

    NASA Astrophysics Data System (ADS)

    Lockyer, Allen J.; Alt, Kevin H.; Kudva, Jayanth N.; Kinslow, Robert W.; Goetz, Allan C.

    1997-06-01

    As the Wright Lab Air Force military contrast `Smart Skin Structures Technology Demonstration' (S3TD) Contract No. F33615-C-93-3200 draws toward conclusion, pertinent features of the program finite element modeling are presented. Analysis was performed to predict the structural performance of a complex multilayered composite panel that will be tested structurally (and electrically) for the final program deliverable. Application of finite element modeling to predict component load path and strain distribution in sandwich panel construction has been reported elsewhere in the literature for more standard applications. However, the unauthordox sandwich configuration lay-up posed by the quite revolutionary S3TD CLAS aircraft fuselage panel demonstration article merits further discussion. Difficulties with material selection, the stumbling block for many programs, are further exacerbated by conflicting material properties required to support simultaneous electrical and structural performance roles. The structural analysis challenge derives from S3TD's unique program goal, namely, to investigate load bearing antennas structural configurations, rather than conventional structurally inefficient `bolt in' installations, that have been the modus operandi for tactical aircraft antenna installations to date. Discussed below is a cost saving strategy where use of linear finite element analysis has been employed in the prediction of key structural parameters, and validated with risk reduction sub panel measurements, before proceeding to the final fabrication of a full scale 36 by 36 inch CLAS panel demonstration article.

  15. Blast wave exposure impairs memory and decreases axon initial segment length.

    PubMed

    Baalman, Kelli L; Cotton, R James; Rasband, S Neil; Rasband, Matthew N

    2013-05-01

    Exposure to a blast wave has been proposed to cause mild traumatic brain injury (mTBI), with symptoms including altered cognition, memory, and behavior. This idea, however, remains controversial, and the mechanisms of blast-induced brain injury remain unknown. To begin to resolve these questions, we constructed a simple compressed air shock tube, placed rats inside the tube, and exposed them to a highly reproducible and controlled blast wave. Consistent with the generation of a mild injury, 2 weeks after exposure to the blast, we found that motor performance was unaffected, and a panel of common injury markers showed little or no significant changes in expression in the cortex, corpus callosum, or hippocampus. Similarly, we were unable to detect elevated spectrin breakdown products in brains collected from blast-exposed rats. Using an object recognition task, however, we found that rats exposed to a blast wave spent significantly less time exploring a novel object when compared with control rats. Intriguingly, we also observed a significant shortening of the axon initial segment (AIS) in both the cortex and hippocampus of blast-exposed rats, suggesting altered neuronal excitability after exposure to a blast. A computational model showed that shortening the AIS increased both threshold and the interspike interval of repetitively firing neurons. These results support the conclusion that exposure to a single blast wave can lead to mTBI with accompanying cognitive impairment and subcellular changes in the molecular organization of neurons.

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

    PubMed Central

    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. PMID:25904891

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

    PubMed

    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.

  18. Monitoring of airborne fungal spore load in relation to meteorological factors, air pollutants and allergic symptoms in Farakka, an unexplored biozone of eastern India.

    PubMed

    Roy, Shipra; Chakraborty, Arindom; Maitra, Saibal; Bhattacharya, Kashinath

    2017-08-01

    Fungi are important components of atmosphere which play a major role in causing respiratory allergy upon inhalation. An airborne fungal spore survey was carried out in two outdoor environments in Farakka-an unexplored township covering the National Thermal Power Station, West Bengal, India for a period of 2 years (October 2013 to September 2015). A Burkard personal volumetric air sampler was used at 15 days interval to collect the total fungal spore load. A fungal spore calendar has been prepared depicting monthly average spore concentration in the air. The relationships between fungal spore concentration and different climatic factors were analysed statistically. Higher concentration levels of aerospora and pollutants were recorded during winter season. A detailed questionnaire was used to obtain medical history data of 523 local patients visiting the outpatients department of Farakka NTPC (National Thermal Power Station) hospital. A significant positive correlation was found between fungal spore concentration, atmospheric pollutants and allergic manifestation. The dominant fungal spores were isolated, sub-cultured and tested for allergenic potential by skin prick tests (SPTs) among subjects with clinical history of respiratory allergy, which evoked ˃45.0% skin reactivity upon individuals.

  19. Role of hydrogen in blast furnaces to improve productivity and decrease coke consumption

    SciTech Connect

    Agarwal, J.C.; Brown, F.C.; Chin, D.L.; Stevens, G.; Clark, R.; Smith, D.

    1995-12-01

    The hydrogen contained in blast furnace gases exerts a variety of physical, thermochemical, and kinetic effects as the gases pass through the various zones. The hydrogen is derived from two sources: (1) the dissociation of moisture in the blast air (ambient and injected with hot blast), and (2) the release from partial combustion of supplemental fuels (including moisture in atomizing water, steam, or transport air, if any). With each atom of oxygen (or carbon), the molar amounts of hydrogen released are more than six times higher for natural gas than for coal, and two times higher for natural gas than for oil. Injection of natural gas in a blast furnace is not a new process. Small amounts of natural gas--about 50--80 lb or 1,100--1,700 SCF/ton of hot metal--have been injected in many of the North American blast furnaces since the early 1960s, with excellent operating results. What is new, however, is a batter understanding of how natural gas reacts in the blast furnace and how natural gas and appropriate quantities of oxygen can be used to increase the driving rate or combustion rate of carbon (coke) in the blast furnace without causing hanging furnace and operating problems. The paper discusses the factors limiting blast furnace productivity and how H{sub 2} and O{sub 2} can increase productivity.

  20. Blasting-induced damage in coal

    SciTech Connect

    Kabongo, K.K.

    1995-12-31

    The paper is drawn from a project intended to explore a technique of prediction, control and optimization of fracture in coal induced by blasting. It evaluates the fines generated in coal submitted to dynamic loading stresses in an impact stamp mortar. The aim is to analyze a complex phenomenon of coal response to blast-generated stresses from a series of discrete simulations of shock and gas actions in controllable processes. It is learned that despite the nucleation of primary crushing and fractures to originate from the point of impact energy in coal, a secondary crushing appears to depart from within the burden progressing towards the free boundaries. The extension of the secondary crushing zone appears to be influenced by the magnitude of the breaking stresses generated and the coal burden distance. A strong dependence of fines on the coal`s innate discontinuities (strength) and the energy input is highlighted.

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

    PubMed

    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

  2. Experimental magnesium depletion in adult rabbits caused by blast overpressure.

    PubMed

    Cernak, I; Radosevic, P; Malicevic, Z; Savic, J

    1995-09-01

    The complex pressure wave (blast) generated by some explosions causes pulmonary pathological changes which resemble the histological findings of the adult respiratory distress syndrome (ARDS). The development of indirect neurotrauma following experimental pulmonary blast injury has been shown previously. The purpose of this study was to evaluate lung and brainstem total tissue magnesium concentrations in adult rabbits following pulmonary blast injury. In order to assess the interrelationship between magnesium and other secondary injury factors, total calcium and high energy phosphate (phosphocreatine, PCr; adenosine triphosphate, ATP) contents were simultaneously measured. Twenty adult male rabbits were divided into two groups. Group C (n = 10) served as control, while group B (n = 10) was subjected to a focused blast wave, generated in laboratory conditions using an air-driven shock tube. Moderate pulmonary blast injury was verified by histological examination in group B. Total tissue magnesium and calcium contents were measured by atomic absorption spectrophotometry in the lungs and brainstem of adult rabbits 30 min following blast overpressure and in their uninjured controls. Simultaneously, PCr and ATP contents were measured by fluorimetric enzymatic analyses in same structures. Lung and brainstem water contents were determined by wet weight to dry weight ratio. Blast overpressure to the lungs induced significant magnesium depletion, increased calcium and decreased the Mg/Ca ratio in lung tissue of injured animals. Increases in water content and PCr/ATP ratio were also observed. Significant correlations between these Mg/Ca and PCr/ATP and between Mg and ATP parameters confirmed the functional relationship between magnesium depletion and impaired bioenergetic state in indirect neurotrauma in adult rabbits through blast overpressure.

  3. Reactivity and Fragmentation of Aluminum-based Structural Energetic Materials under Explosive Loading

    NASA Astrophysics Data System (ADS)

    Glumac, Nick; Clemenson, Michael; Guadarrama, Jose; Krier, Herman

    2015-06-01

    Aluminum-cased warheads have been observed to generate enhanced blast and target damage due to reactivity of the aluminum fragments with ambient air. This effect can more than double the output of a conventional warhead. The mechanism by which the aluminum reacts under these conditions remains poorly understood. We undertake a highly controlled experimental study to investigate the phenomenon of aluminum reaction under explosive loading. Experiments are conducted with Al 6061 casings and PBX-N9 explosive with a fixed charge to case mass ratio of 1:2. Results are compared to inert casings (steel), as well as to tests performed in nitrogen environments to isolate aerobic and anaerobic effects. Padded walls are used in some tests to isolate the effects of impact-induced reactions, which are found to be non-negligible. Finally, blast wave measurements and quasi-static pressure measurements are used to isolate the fraction of case reaction that is fast enough to drive the primary blast wave from the later time reaction that generates temperature and overpressure only in the late-time fireball. Fragment size distributions, including those in the micron-scale range, are collected and quantified.

  4. Low-Level Blast Exposure Increases Transient Receptor Potential Vanilloid 1 (TRPV1) Expression in the Rat Cornea

    PubMed Central

    Por, Elaine D.; Choi, Jae-Hyek; Lund, Brian J.

    2016-01-01

    ABSTRACT Background: Blast-related ocular injuries sustained by military personnel have led to rigorous efforts to elucidate the effects of blast exposure on neurosensory function. Recent studies have provided some insight into cognitive and visual deficits sustained following blast exposure; however, limited data are available on the effects of blast on pain and inflammatory processes. Investigation of these secondary effects of blast exposure is necessary to fully comprehend the complex pathophysiology of blast-related injuries. The overall purpose of this study is to determine the effects of single and repeated blast exposure on pain and inflammatory mediators in ocular tissues. Methods: A compressed air shock tube was used to deliver a single or repeated blast (68.0 ± 2.7 kPa) to anesthetized rats daily for 5 days. Immunohistochemistry was performed on ocular tissues to determine the expression of the transient receptor potential vanilloid 1 (TRPV1) channel, calcitonin gene-related peptide (CGRP), substance P (SP), and endothelin-1 (ET-1) following single and repeated blast exposure. Neutrophil infiltration and myeloperoxidase (MPO) expression were also assessed in blast tissues via immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) analysis, respectively. Results: TRPV1 expression was increased in rat corneas exposed to both single and repeated blast. Increased secretion of CGRP, SP, and ET-1 was also detected in rat corneas as compared to control. Moreover, repeated blast exposure resulted in neutrophil infiltration in the cornea and stromal layer as compared to control animals. Conclusion: Single and repeated blast exposure resulted in increased expression of TRPV1, CGRP, SP, and ET-1 as well as neutrophil infiltration. Collectively, these findings provide novel insight into the activation of pain and inflammation signaling mediators following blast exposure. PMID:27049881

  5. Low-Level Blast Exposure Increases Transient Receptor Potential Vanilloid 1 (TRPV1) Expression in the Rat Cornea.

    PubMed

    Por, Elaine D; Choi, Jae-Hyek; Lund, Brian J

    2016-10-01

    Blast-related ocular injuries sustained by military personnel have led to rigorous efforts to elucidate the effects of blast exposure on neurosensory function. Recent studies have provided some insight into cognitive and visual deficits sustained following blast exposure; however, limited data are available on the effects of blast on pain and inflammatory processes. Investigation of these secondary effects of blast exposure is necessary to fully comprehend the complex pathophysiology of blast-related injuries. The overall purpose of this study is to determine the effects of single and repeated blast exposure on pain and inflammatory mediators in ocular tissues. A compressed air shock tube was used to deliver a single or repeated blast (68.0 ± 2.7 kPa) to anesthetized rats daily for 5 days. Immunohistochemistry was performed on ocular tissues to determine the expression of the transient receptor potential vanilloid 1 (TRPV1) channel, calcitonin gene-related peptide (CGRP), substance P (SP), and endothelin-1 (ET-1) following single and repeated blast exposure. Neutrophil infiltration and myeloperoxidase (MPO) expression were also assessed in blast tissues via immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) analysis, respectively. TRPV1 expression was increased in rat corneas exposed to both single and repeated blast. Increased secretion of CGRP, SP, and ET-1 was also detected in rat corneas as compared to control. Moreover, repeated blast exposure resulted in neutrophil infiltration in the cornea and stromal layer as compared to control animals. Single and repeated blast exposure resulted in increased expression of TRPV1, CGRP, SP, and ET-1 as well as neutrophil infiltration. Collectively, these findings provide novel insight into the activation of pain and inflammation signaling mediators following blast exposure.

  6. Mass loading of size-segregated atmospheric aerosols in the ambient air during fireworks episodes in eastern Central India.

    PubMed

    Nirmalkar, Jayant; Deb, Manas K; Deshmukh, Dhananjay K; Verma, Santosh K

    2013-04-01

    The effects of combustion of the fire crackers on the air quality in eastern Central India were studied for the first time during Diwali festival. This case study analyzes the size distribution and temporal variation of aerosols collected in the rural area of eastern Central India during pre-diwali, Diwali and post-diwali period for the year of 2011. Fifteen aerosol samples were collected during the special case study of Diwali period using Andersen sampler. The mean concentrations of PM10 (respirable particulate matter) were found to be 212.8 ± 4.2, 555.5 ± 20.2 and 284.4 ± 5.8 during pre-diwali, Diwali and post-diwali period, respectively. During Diwali festival PM10 concentration was about 2.6 and 1.9 times higher than pre-diwali and post-diwali period, respectively. PM2.5 (fine) and PM1 (submicron) concentrations during Diwali festival were more than 2 times higher than pre-diwali and post-diwali.

  7. Impact and Blast Resistance of Sandwich Plates

    NASA Astrophysics Data System (ADS)

    Dvorak, George J.; Bahei-El-Din, Yehia A.; Suvorov, Alexander P.

    Response of conventional and modified sandwich plate designs is examined under static load, impact by a rigid cylindrical or flat indenter, and during and after an exponential pressure impulse lasting for 0.05 ms, at peak pressure of 100 MPa, simulating a nearby explosion. The conventional sandwich design consists of thin outer (loaded side) and inner facesheets made of carbon/epoxy fibrous laminates, separated by a thick layer of structural foam core. In the three modified designs, one or two thin ductile interlayers are inserted between the outer facesheet and the foam core. Materials selected for the interlayers are a hyperelas-tic rate-independent polyurethane;a compression strain and strain rate dependent, elastic-plastic polyurea;and an elastomeric foam. ABAQUS and LS-Dyna software were used in various response simulations. Performance comparisons between the enhanced and conventional designs show that the modified designs provide much better protection against different damage modes under both load regimes. After impact, local facesheet deflection, core compression, and energy release rate of delamination cracks, which may extend on hidden interfaces between facesheet and core, are all reduced. Under blast or impulse loads, reductions have been observed in the extent of core crushing, facesheet delaminations and vibration amplitudes, and in overall deflections. Similar reductions were found in the kinetic energy and in the stored and dissipated strain energy. Although strain rates as high as 10-4/s1 are produced by the blast pressure, peak strains in the interlayers were too low to raise the flow stress in the polyurea to that in the polyurethane, where a possible rate-dependent response was neglected. Therefore, stiff polyurethane or hard rubber interlayers materials should be used for protection of sandwich plate foam cores against both impact and blast-induced damage.

  8. Comparative Research to Surface Aeration and Blasting Aeration System Based on LCC Theory

    NASA Astrophysics Data System (ADS)

    Liai, CHEN; Hongxun, HOU; Weibiao, FEI; Eryan, ZHAO

    2017-05-01

    It is difficult to select the suitable aeration system for the designers of wastewater treatment plant (WWTP). In this paper, taking two WWTPs with surface aeration systems and blasting aeration respectively for an example, LCC theory was adapted to analysis the cost of consumption and the environmental impact, which caused by the different aeration system. Research results showed that: (1) In the 20-year life cycle, the LCC mainly depended on the cost of energy consumption whatever blasting aeration system or surface aeration, while the LCC of blasting aeration system affected by the equipment maintenance cost, maintenance cost, economic losses caused by wastewater loss and environmental load in maintenance period. (2) The LCC of blasting aeration system was lower than the surface aeration in general, on the premise of the standard discharge; (3) the blasting aeration system estimated a saving of 60,0000RMB annually in costs compared with the surface aeration.

  9. Cold-air investigation of a 3 1/2-stage fan-drive turbine with a stage loading factor of 4 designed for an integral lift engine. 1: Turbine design and performance of first stage

    NASA Technical Reports Server (NTRS)

    Whitney, W. J.; Schum, H. J.; Behning, F. P.

    1975-01-01

    The design of the 3 1/2-stage turbine is described, and the cold-air performance of the first stage, modified for axial inlet conditions, is presented. The performance of the modified single-stage turbine and of two comtemporary high-stage-loading-factor turbines is compared with that estimated with a reference prediction method.

  10. Cold blast furnace syndrome: a new source of toxic inhalation by nitrogen oxides

    PubMed Central

    Tague, I; Llewellin, P; Burton, K; Buchan, R; Yates, D

    2004-01-01

    Methods: Fourteen workers developed acute respiratory symptoms shortly after exposure to "air blast" from blast furnace tuyeres. These included chest tightness, dyspnoea, rigors, and diaphoresis. Chest radiographs showed pulmonary infiltrates, and lung function a restrictive abnormality. This report includes a description of clinical features of the affected workers and elucidation of the probable cause of the outbreak. Results: Clinical features and occupational hygiene measurements suggested the most likely cause was inhalation of nitrogen oxides at high pressure and temperature. While the task could not be eliminated, engineering controls were implemented to control the hazard. No further cases have occurred. Conclusions: "Cold blast furnace syndrome" represents a previously undescribed hazard of blast furnace work, probably due to inhalation of nitrogen oxides. It should be considered in the differential diagnosis of acute toxic inhalational injuries in blast furnace workers. PMID:15090669

  11. Remote operated vehicle with carbon dioxide blasting (ROVCO{sub 2})

    SciTech Connect

    Resnick, A.M.

    1995-10-01

    The Remote Operated Vehicle with Carbon Dioxide Blasting (ROVCO{sub 2}), as shown in a front view is a six-wheeled remote land vehicle used to decontaminate concrete floors. The remote vehicle has a high pressure Cryogenesis blasting subsystem, Oceaneering Technologies (OTECH) developed a CO{sub 2} xY Orthogonal Translational End Effector (COYOTEE) subsystem, and a vacuum/filtration and containment subsystem. The cryogenesis subsystem performs the actual decontamination work and consists of the dry ice supply unit, the blasting nozzle, the remotely controlled electric and pneumatic valves, and the vacuum work-head. The COYOTEE subsystem positions the blasting work-head within a planar work space and the vacuum subsystem provides filtration and containment of the debris generated by the CO{sub 2} blasting. It employs a High Efficiency Particulate Air (HEPA) filtration unit to separate contaminants for disposal. All of the above systems are attached to the vehicle subsystem via the support structure.

  12. Physical Modelling of Mine Blast Impact on Armoured Vehicles

    NASA Astrophysics Data System (ADS)

    Bochorishvili, Nika; Chikhradze, Nikoloz; Mataradze, Edgar; Akhvlediani, Irakli

    2016-10-01

    Studies related to the impact of a mine blast on armoured vehicles focus on aspects such as i) dynamic loads acting on the armoured vehicle at the moment of mine blast; ii) armoured vehicle response under the impact of a dynamic load; iii) dynamic loads acting on the crew and the assessment of potential human traumas. The paper presents similarity criteria for physical modelling of the mine blast under the armoured vehicle and the results of modelling of dynamic behaviour of vehicles. Similarity criteria, established as a result of the analysis of the governing parameters and similarity theory, are adequate to the processes of blast impact on the vehicle. Modelling experiments were conducted in the underground experimental base of the Mining Institute especially designed for the study of explosion processes. Physical modelling can be used for preliminary studies with the purpose of the evaluation of the protective level of armoured vehicles as well as for pre-testing experiments in accordance with STANAG 4569 requirements.

  13. Fuel burner with air-deflecting object and method therefor

    SciTech Connect

    Durfee, E.P.

    1980-12-16

    There is provided an improved fuel burner of the type having an air blower and blast tube. The improvement involves placement of an air-deflecting object inside the housing of the air blower or in the blast tube. In one embodiment, the object has a v-shaped cross section, and is attached to a gently tapered cylinder; the object can be held in place by inserting it through a hole of appropriate dimension in the air blower or blast tube, and tapping on the exposed end of the tapered cylinder until the latter is engaged in the hole. There is also provided a method of improving a fuel burner by mounting a air-deflecting object of the type described in the air blower housing or in the blast tube.

  14. Injury biomechanics, neuropathology, and simplified physics of explosive blast and impact mild traumatic brain injury.

    PubMed

    Bandak, F A; Ling, G; Bandak, A; De Lanerolle, N C

    2015-01-01

    Explosive blast shock waves and blunt impact to the head are two types of loading shown to result in mild traumatic brain injury (mTBI). While mTBI from these two causes shares some common features behaviorally, there are distinct differences in the pathophysiology of the underlying injury mechanisms. Various elucidations have been offered in the literature to explain the organic damage associated with mTBI resulting from both types of loading. The current state of understanding in this field is somewhat limited by the degree of appreciation of the physics and biomechanics governing the effects of explosive blast shock waves and blunt impact on the head, which has resulted in the various approaches to the investigation of the operative brain injury "wounding mechanisms". In this chapter we provide a simplified description of terminology associated with forces on the head from explosive blast shock waves and blunt impact, to assist readers in the field in evaluating interpretations of brain injury "wounding" processes. Remarkably, mTBI from either loading is shown generally to result in only a small loss of neurons, with hippocampal neurons appearing to be particularly vulnerable to explosive blast shock waves. Explosive blast studies in large animal models show a unique pattern of periventricular injury, which is different from the classic diffuse axonal injury. Both astrocyte and microglial activation are also seen in explosive blast as well as impact trauma, but this may be a general secondary brain injury response, nonspecific to explosive blast or blunt trauma. Additionally, while moderate to severe impact closed head injuries sometimes result in petechial hemorrhages or hematomas, they do not appear to be associated with explosive blast mTBI even with repeated exposure to blasts.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. 25. "GAFFTC 19 OCT 60, BLAST EFFECTS ON AIRFOILS, STATIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. "G-AFFTC 19 OCT 60, BLAST EFFECTS ON AIRFOILS, STATIC RUN 5." View of track rail mounting and the water brake trough at 20,000-foot track. Looking northeast. File no. 12,358-60. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  17. Dynamic Properties of Human Tympanic Membrane After Exposure to Blast Waves.

    PubMed

    Engles, Warren G; Wang, Xuelin; Gan, Rong Z

    2017-06-20

    Blast overpressure causes dynamic damage to middle ear components, and tympanic membrane (TM) rupture is the most frequent middle ear injury. However, it is unclear how the blast waves change mechanical properties of the TM and affect sound transmission through the ear. This paper reports the current study on dynamic properties of the TM after exposure to blast waves by using acoustic loading and laser Doppler vibrometry (LDV). The TM specimens were prepared from human temporal bones following exposures to blast overpressure. Vibration of the TM specimen induced by acoustic loading was measured by LDV over a frequency range of 200-8000 Hz. An inverse-problem solving method with finite element modeling was used to determine the complex modulus of the TM specimen. The post-blast storage modulus ranged from 23.1 to 26.9 MPa, and loss modulus ranged from 0.09 to 3.78 MPa as frequency increased from 200 to 8000 Hz. Compared to the complex modulus of normal TM reported in the literature, the post-blast storage and loss modulus decreased significantly across the frequency range. The scanning electron microscopy (SEM) images of the post-blast TM samples showed microstructural changes of the tissue, which explained the alteration of mechanical properties of the TM samples.

  18. Single Pass Streaming BLAST on FPGAs*†

    PubMed Central

    Herbordt, Martin C.; Model, Josh; Sukhwani, Bharat; Gu, Yongfeng; VanCourt, Tom

    2008-01-01

    Approximate string matching is fundamental to bioinformatics and has been the subject of numerous FPGA acceleration studies. We address issues with respect to FPGA implementations of both BLAST- and dynamic-programming- (DP) based methods. Our primary contribution is a new algorithm for emulating the seeding and extension phases of BLAST. This operates in a single pass through a database at streaming rate, and with no preprocessing other than loading the query string. Moreover, it emulates parameters turned to maximum possible sensitivity with no slowdown. While current DP-based methods also operate at streaming rate, generating results can be cumbersome. We address this with a new structure for data extraction. We present results from several implementations showing order of magnitude acceleration over serial reference code. A simple extension assures compatibility with NCBI BLAST. PMID:19081828

  19. Blast impact behaviour of concrete with different fibre reinforcement

    NASA Astrophysics Data System (ADS)

    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. Additional cooling and heating load improvements in seasonal performance modeling of room and central air conditioners and heat pumps. Topical report, Subtask 3. 2

    SciTech Connect

    Not Available

    1980-04-09

    The study focuses on improving the load modeling technique of Seasonal Performance Model (SPM) in order to estimate a more realistic load for seasonal analysis calculations on an hourly basis. A computer simulation program, Seasonal Performance Model Load (SPMLD), was used to calculate the cooling and heating loads for a typical residence in Caribou, Maine; Columbia, Missouri; and Fort Worth, Texas. The derivation of the SPMLD is described and changes made to improve cooling and heating load estimates are identified. (MCW)

  1. High efficiency air cycle air conditioning system

    SciTech Connect

    Rannenberg, G. C.

    1985-11-19

    An air cycle air conditioning system is provided with regenerative heat exchangers upstream and downstream of an expansion turbine. A closedloop liquid circulatory system serially connects the two regenerative heat exchangers for regeneration without the bulk associated with air-to-air heat exchange. The liquid circulatory system may also provide heat transport to a remote sink heat exchanger and from a remote load as well as heat exchange within the sink heat exchanger and load for enhanced compactness and efficiency.

  2. A Neural-Network Model-Based Engineering Tool for Blast Wall Protection of Structures (Postprint)

    DTIC Science & Technology

    2011-06-01

    to predicting blast loads with protective blast walls includes case-specific computational modeling with software such as LS-DYNA [12], AUTODYN [13...approach, but used simulation models (based on AUTODYN ), rather than live experiments, to generate a database of pressure-time histories over the...field airblast problem. The results are also compared against existing work determining a GCI for LS-DYNA, CTH, and AUTODYN [31]. Results from the two

  3. Quantifying Momentum Transfer Due to Blast Waves from Oxy-Acetylene Driven Shock Tubes

    DTIC Science & Technology

    2012-05-30

    Transfer Due to Blast Waves from Oxy - Acetylene Driven Shock Tubes 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...and the response of materiel to blast loading. Recently, laboratory-scale shock tubes driven by oxy - acetylene were described. It was estimated that...later. In each case, most of the momentum transfer was due to the shock wave itself. The results support previous estimates that the oxy - acetylene

  4. Micro-blast waves using detonation transmission tubing

    NASA Astrophysics Data System (ADS)

    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 < Δ {p}/{p}_0 ≲ 0.02) gave good agreement with the 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.

  5. EXAMINING LETHALITY RISK FOR RODENT STUDIES OF PRIMARY BLAST LUNG INJURY

    PubMed Central

    Hubbard, William Brad; Hall, Christina; Sajja, Venkata Siva Sai Sujith; Lavik, Erin; VandeVord, Pamela

    2015-01-01

    While protective measures have been taken to mitigate injury to the thorax during a blast exposure, primary blast lung injury (PBLI) is still evident in mounted/in vehicle cases during military conflicts. Moreover, civilians, who are unprotected from blast exposure, can be severely harmed by terrorist attacks that use improvised explosive devices (IEDs). Since the lungs are the most susceptible organ due to their air-filled nature, PBLI is one of the most serious injuries seen in civilian blast cases. Determining lethality threshold for rodent studies is crucial to guide experimental designs centered on therapies for survival after PBLI or mechanistic understanding of the injury itself. Using an Advanced Blast Simulator, unprotected rats were exposed to a whole body blast to induce PBLI. The one-hour survival rate was assessed to determine operating conditions for a 50% lethality rate. Macroscopic and histological analysis of lung was conducted using hematoxylin and eosin staining. Results demonstrated lethality risk trends based on static blast overpressure (BOP) for rodent models, which may help standardized animal studies and contribute to scaling to the human level. The need for a standardized method of producing PBLI is pressing and establishing standard curves, such as a lethality risk curve for lung blasts, is crucial for this condensing of BOP methods. PMID:25405409

  6. Blast-Induced Color Change in Photonic Crystals Corresponds with Brain Pathology

    PubMed Central

    Cullen, D. Kacy; Browne, Kevin D.; Xu, Yongan; Adeeb, Saleena; Wolf, John A.; McCarron, Richard M.; Yang, Shu; Chavko, Mikulas

    2011-01-01

    Abstract A high incidence of blast exposure is a 21st century reality in counter-insurgency warfare. However, thresholds for closed-head blast-induced traumatic brain injury (bTBI) remain unknown. Moreover, without objective information about relative blast exposure, warfighters with bTBI may not receive appropriate medical care and may remain in harm's way. Accordingly, we have engineered a blast injury dosimeter (BID) using a photonic crystalline material that changes color following blast exposure. The photonic crystals are fabricated using SU-8 via multi-beam interference laser lithography. The final BID is similar in appearance to an array of small colored stickers that may be affixed to uniforms or helmets in multiple locations. Although durable under normal conditions, the photonic crystalline micro- and nano-structure are precisely altered by blast to create a color change. These BIDs were evaluated using a rat model of bTBI, for which blast shockwave exposure was generated via a compressed air-driven shock tube. With prototype BID arrays affixed to the animals, we found that BID color changes corresponded with subtle brain pathologies, including neuronal degeneration and reactive astrocytosis. These subtle changes were most notable in the dentate gyrus of the hippocampus, cerebral cortex, and cerebellum. These data demonstrate the feasibility of using a materials-based, power-free colorimetric BID as the first self-contained blast sensor calibrated to correspond with brain pathology. PMID:22082449

  7. Reactive bromine chemistry in Mount Etna's volcanic plume: the influence of total Br, high-temperature processing, aerosol loading and plume-air mixing

    NASA Astrophysics Data System (ADS)

    Roberts, T. J.; Martin, R. S.; Jourdain, L.

    2014-10-01

    Volcanic emissions present a source of reactive halogens to the troposphere, through rapid plume chemistry that converts the emitted HBr to more reactive forms such as BrO. The nature of this process is poorly quantified, yet is of interest in order to understand volcanic impacts on the troposphere, and infer volcanic activity from volcanic gas measurements (i.e. BrO / SO2 ratios). Recent observations from Etna report an initial increase and subsequent plateau or decline in BrO / SO2 ratios with distance downwind. We present daytime PlumeChem model simulations that reproduce and explain the reported trend in BrO / SO2 at Etna including the initial rise and subsequent plateau. Suites of model simulations also investigate the influences of volcanic aerosol loading, bromine emission, and plume-air mixing rate on the downwind plume chemistry. Emitted volcanic HBr is converted into reactive bromine by autocatalytic bromine chemistry cycles whose onset is accelerated by the model high-temperature initialisation. These rapid chemistry cycles also impact the reactive bromine speciation through inter-conversion of Br, Br2, BrO, BrONO2, BrCl, HOBr. We predict a new evolution of Br speciation in the plume. BrO, Br2, Br and HBr are the main plume species near downwind whilst BrO and HOBr are present further downwind (where BrONO2 and BrCl also make up a minor fraction). BrNO2 is predicted to be only a relatively minor plume component. The initial rise in BrO / SO2 occurs as ozone is entrained into the plume whose reaction with Br promotes net formation of BrO. Aerosol has a modest impact on BrO / SO2 near-downwind (< ~6 km, ~10 min) at the relatively high loadings considered. The subsequent decline in BrO / SO2 occurs as entrainment of oxidants HO2 and NO2 promotes net formation of HOBr and BrONO2, whilst the plume dispersion dilutes volcanic aerosol so slows the heterogeneous loss rates of these species. A higher volcanic aerosol loading enhances BrO / SO2 in the (> 6 km

  8. Visual system degeneration induced by blast overpressure.

    PubMed

    Petras, J M; Bauman, R A; Elsayed, N M

    1997-07-25

    The effect of blast overpressure on visual system pathology was studied in 14 male Sprague-Dawley rats weighing 360-432 g. Blast overpressure was simulated using a compressed-air driven shock tube, with the aim of studying a range of overpressures causing sublethal injury. Neither control (unexposed) rats nor rats exposed to 83 kiloPascals (kPa) overpressure showed evidence of visual system pathology. Neurological injury to brain visual pathways was observed in male rats surviving blast overpressure exposures of 104-110 kPa and 129-173 kPa. Optic nerve fiber degeneration was ipsilateral to the blast pressure wave. The optic chiasm contained small numbers of degenerated fibers. Optic tract fiber degeneration was present bilaterally, but was predominantly ipsilateral. Optic tract fiber degeneration was followed to nuclear groups at the level of the midbrain, midbrain-diencephalic junction, and the thalamus where degenerated fibers arborized among the neurons of: (i) the superior colliculus, (ii) pretectal region, and (iii) the lateral geniculate body. The superior colliculus contained fiber degeneration localized principally to two superficial layers (i) the stratum opticum (layer III) and (ii) stratum cinereum (layer II). The pretectal area contained degenerated fibers which were widespread in (i) the nucleus of the optic tract, (ii) olivary pretectal nucleus, (iii) anterior pretectal nucleus, and (iv) the posterior pretectal nucleus. Degenerated fibers in the lateral geniculate body were not universally distributed. They appeared to arborize among neurons of the dorsal and ventral nuclei: the ventral lateral geniculate nucleus (parvocellular and magnocellular parts); and the dorsal lateral geniculate nucleus. The axonopathy observed in the central visual pathways and nuclei of the rat brain are consistent with the presence of blast overpressure induced injury to the retina. The orbital cavities of the human skull contain frontally-directed eyeballs for binocular

  9. Utilization of Fast Running Models in Buried Blast Simulations of Ground Vehicles for Significant Computational Efficiency

    DTIC Science & Technology

    2013-08-07

    threat LS - Dyna Eulerian analysis for 2-stage analysis LS - Dyna Lagrangian analysis for 2-stage analysis Create fast running models for underbody blast ...studies Use fast running models for underbody blast studies LS - Dyna Lagrangian analysis for 2-stage analysis Generate air/soil/explosive model...average velocity results correlate well with LS - DYNA simulation over 12 evaluation points UNCLASSIFIED Conclusions • FRMs enable rapid

  10. Rapid miniature fiber optic pressure sensors for blast wave measurements

    NASA Astrophysics Data System (ADS)

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Niezrecki, Christopher; Chen, Julie; Wang, Xingwei

    2013-02-01

    Traumatic brain injury (TBI) is a serious potential threat to soldiers who are exposed to explosions. Since the pathophysiology of TBI associated with a blast wave is not clearly defined, it is crucial to have a sensing system to accurately quantify the blast wave dynamics. This paper presents an ultra-fast fiber optic pressure sensor based on Fabry-Perot (FP) interferometric principle that is capable of measuring the rapid pressure changes in a blast event. The blast event in the experiment was generated by a starter pistol blank firing at close range, which produced a more realistic wave profile compared to using compressed air driven shock tubes. To the authors' knowledge, it is also the first study to utilize fiber optic pressure sensors to measure the ballistics shock wave of a pistol firing. The results illustrated that the fiber optic pressure sensor has a rise time of 200 ns which demonstrated that the sensor has ability to capture the dynamic pressure transient during a blast event. Moreover, the resonant frequency of the sensor was determined to be 4.11 MHz, which agrees well with the specific designed value.

  11. 2016 SUMMER BLAST PICNIC

    NASA Image and Video Library

    2016-06-09

    MARSHALL SPACE FLIGHT CENTER DIRECTOR TODD MAY CASTS HIS BALLOT IN THE HOMEMADE ICE CREAM CONTEST DURING THE GREAT EXCHANGE SUMMER BLAST SOCIAL, PRESENTED JUNE 9 BY THE MARSHALL EXCHANGE. THE EXCHANGE IS A NON-APPROPRIATED-FUND ACTIVITY THAT AIMS TO CONTRIBUTE TO THE WELFARE, EFFICIENCY AND MORALE OF MARSHALL TEAM MEMBERS, OTHER GOVERNMENT PERSONNEL, RETIRED NASA EMPLOYEES AND THEIR FAMILIES.

  12. Muzzle Blast Amplification

    DTIC Science & Technology

    1976-11-01

    Report) 1». SUPPLEMENTARY NOTES 19. KEY WORDS (Contlnua on reverse » Ida if nacaaeary and Identity by block number) Muzzle Blast...Range NM 88002 Commander US Army Research Office ATTN: CRD -AA-EH P. 0. Box 12211 Research Triangle Park NC 27709 Director US Army BMD Advanced

  13. Metallurgical Evaluation of Grit Blasted Versus Non-Grit Blasted Iridium Alloy Clad Vent Set Cup Surfaces

    SciTech Connect

    Ulrich, George B; Longmire, Hu Foster

    2010-02-01

    Metallurgical evaluations were conducted to determine what, if any, grain size differences exist between grit blasted and non-grit blasted DOP-26 iridium alloy cup surfaces and if grit blasting imparts sufficient compressive cold work to induce abnormal grain growth during subsequent temperature exposures. Metallographic measurements indicated that grit blasting cold worked the outside cup surface to a depth of approximately 19 {micro}m. Subsequent processing through the air burn-off (635 C/4h) and vacuum outgassing (1250 C/1h) operations was found to uniformly recrystallize the cold worked surface to produce grains with an average diameter of approximately 8.5 {micro}m (American Society for Testing and Materials (ASTM) grain size number 11). Follow-on heat treatments at 1375 C, 1500 C, and 1900 C for durations ranging from 1 min to 70 h yielded uniform grain sizes and no abnormal grain growth from grit blasting. Abnormal grain growth was noted at the 1500 C and 1900 C heat treatments in areas of cold work from excessive clamping during sample preparation.

  14. BLAST: THE REDSHIFT SURVEY

    SciTech Connect

    Eales, Stephen; Dye, Simon; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo; Raymond, Gwenifer; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Scott, Douglas; Devlin, Mark J.; Rex, Marie; Semisch, Christopher; Truch, Matthew D. P.; Hughes, David H.; Netterfield, Calvin B.; Viero, Marco P.; Patanchon, Guillaume; Siana, Brian

    2009-12-20

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently surveyed approx =8.7 deg{sup 2} centered on Great Observatories Origins Deep Survey-South at 250, 350, and 500 mum. In Dye et al., we presented the catalog of sources detected at 5sigma in at least one band in this field and the probable counterparts to these sources in other wavebands. In this paper, we present the results of a redshift survey in which we succeeded in measuring redshifts for 82 of these counterparts. The spectra show that the BLAST counterparts are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey. Roughly one quarter of the BLAST counterparts contain an active nucleus. We have used the spectroscopic redshifts to carry out a test of the ability of photometric redshift methods to estimate the redshifts of dusty galaxies, showing that the standard methods work well even when a galaxy contains a large amount of dust. We have also investigated the cases where there are two possible counterparts to the BLAST source, finding that in at least half of these there is evidence that the two galaxies are physically associated, either because they are interacting or because they are in the same large-scale structure. Finally, we have made the first direct measurements of the luminosity function in the three BLAST bands. We find strong evolution out to z = 1, in the sense that there is a large increase in the space density of the most luminous galaxies. We have also investigated the evolution of the dust-mass function, finding similar strong evolution in the space density of the galaxies with the largest dust masses, showing that the luminosity evolution seen in many wavebands is associated with an increase in the reservoir of interstellar matter in galaxies.

  15. Cooling loads in laboratories

    SciTech Connect

    Wilkins, C.K.; Cook, M.R.

    1999-07-01

    The heating, ventilating, and air-conditioning (HVAC) system for a laboratory must be designed with consideration for safety, air cleanliness, and space temperature. The primary safety concern is to ensure proper coordination between fume hood exhaust and makeup air supply. Air cleanliness is maintained by properly filtering supply air, by delivering adequate room air changes, and by ensuring proper pressure relationships between the laboratory and adjacent spaces. Space temperature is maintained by supplying enough cooling air to offset the amount of heat generated in the room. Each of these factors must be considered, and the one that results in the largest ventilation rate is used to establish the supply and exhaust airflows. The project described in this paper illustrates a case where cooling load is the determining factor in the sizing of the air systems.

  16. Reactive bromine chemistry in Mt. Etna's volcanic plume: the influence of total Br, high temperature processing, aerosol loading and plume-air mixing

    NASA Astrophysics Data System (ADS)

    Roberts, T. J.; Martin, R. S.; Jourdain, L.

    2014-03-01

    Volcanic emissions present a source of reactive halogens to the troposphere, through rapid plume chemistry that converts the emitted HBr to more reactive forms such as BrO. The nature of this process is poorly quantified, yet is of interest to understand volcanic impacts on the troposphere, and infer volcanic activity from volcanic gas measurements (i.e. BrO / SO2 ratios). Recent observations from Etna report an initial increase and subsequent plateau or decline in BrO / SO2 ratios with distance downwind. We present daytime PlumeChem model simulations that reproduce and explain the reported trend in BrO / SO2 at Etna including the initial rise and subsequent plateau. Through suites of model simulations we also investigate the influences of volcanic aerosol loading, bromine emission, and plume-air mixing rate on the downwind plume chemistry. Emitted volcanic HBr is converted into reactive bromine by autocatalytic bromine chemistry cycles whose onset is accelerated by the model high-temperature initialisation. These rapid chemistry cycles also impact the reactive bromine speciation through inter-conversion of Br, Br2, BrO, BrONO2, BrCl, HOBr. Formation of BrNO2 is also discussed. We predict a new evolution of Br-speciation in the plume, with BrO, Br2, Br and HBr as the main plume species in the near downwind plume whilst BrO, and HOBr are present in significant quantities further downwind (where BrONO2 and BrCl also make up a minor fraction). The initial rise in BrO / SO2 occurs as ozone is entrained into the plume whose reaction with Br promotes net formation of BrO. Aerosol has a modest impact on BrO / SO2 near-downwind (< 6 km) at the relatively high loadings considered. The subsequent decline in BrO / SO2 occurs as entrainment of oxidants HO2 and NO2 promotes net formation of HOBr and BrONO2, whilst the plume dispersion dilutes volcanic aerosol so slows the heterogeneous loss rates of these species. A higher volcanic aerosol loading enhances BrO / SO2 in the (> 6

  17. BeoBLAST: distributed BLAST and PSI-BLAST on a Beowulf cluster.

    PubMed

    Grant, J D; Dunbrack, R L; Manion, F J; Ochs, M F

    2002-05-01

    BeoBLAST is an integrated software package that handles user requests and distributes BLAST and PSI-BLAST searches to nodes of a Beowulf cluster, thus providing a simple way to implement a scalable BLAST system on top of relatively inexpensive computer clusters. Additionally, BeoBLAST offers a number of novel search features through its web interface, including the ability to perform simultaneous searches of multiple databases with multiple queries, and the ability to start a search using the PSSM generated from a previous PSI-BLAST search on a different database. The underlying system can also handle automated querying for high throughput work. Source code is available under the GNU public license at http://bioinformatics.fccc.edu/

  18. Biomechanical modeling for the response of human thorax to blast waves

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Tao, Gang

    2015-08-01

    A simplified finite element model of a human thorax had been developed for probing into the mechanical response in simple and complex blast environments. The human thorax model was first created by CT images with blast loading applied via a coupled arbitrary Lagrangian-Eulerian method, allowing for a variety of loads to be considered. The goal is to analyze the maximum stress distributions of lung tissue and peak inward thorax wall velocity and to know the possible regions and levels of lung injury. In parallel, a mathematical model has been modified from the Lobdell model to investigate the detailed percentage of lung injury at each level. The blast loadings around the human thorax were obtained from the finite element model, and were then applied in the mathematical model as the boundary conditions to predict the normalized work of the human thorax lung. The present results are found in agreement with the modified Bowen curves and the results predicted by Axelsson's model.

  19. A Multiscale Approach to Blast Neurotrauma Modeling: Part II: Methodology for Inducing Blast Injury to in vitro Models

    PubMed Central

    Effgen, Gwen B.; Hue, Christopher D.; Vogel, Edward; Panzer, Matthew B.; Meaney, David F.; Bass, Cameron R.; Morrison, Barclay

    2012-01-01

    Due to the prominent role of improvised explosive devices (IEDs) in wounding patterns of U.S. war-fighters in Iraq and Afghanistan, blast injury has risen to a new level of importance and is recognized to be a major cause of injuries to the brain. However, an injury risk-function for microscopic, macroscopic, behavioral, and neurological deficits has yet to be defined. While operational blast injuries can be very complex and thus difficult to analyze, a simplified blast injury model would facilitate studies correlating biological outcomes with blast biomechanics to define tolerance criteria. Blast-induced traumatic brain injury (bTBI) results from the translation of a shock wave in-air, such as that produced by an IED, into a pressure wave within the skull–brain complex. Our blast injury methodology recapitulates this phenomenon in vitro, allowing for control of the injury biomechanics via a compressed-gas shock tube used in conjunction with a custom-designed, fluid-filled receiver that contains the living culture. The receiver converts the air shock wave into a fast-rising pressure transient with minimal reflections, mimicking the intracranial pressure history in blast. We have developed an organotypic hippocampal slice culture model that exhibits cell death when exposed to a 530 ± 17.7-kPa peak overpressure with a 1.026 ± 0.017-ms duration and 190 ± 10.7 kPa-ms impulse in-air. We have also injured a simplified in vitro model of the blood–brain barrier, which exhibits disrupted integrity immediately following exposure to 581 ± 10.0 kPa peak overpressure with a 1.067 ± 0.006-ms duration and 222 ± 6.9 kPa-ms impulse in-air. To better prevent and treat bTBI, both the initiating biomechanics and the ensuing pathobiology must be understood in greater detail. A well-characterized, in vitro model of bTBI, in conjunction with animal models, will be a powerful tool for developing strategies to mitigate the risks of bTBI. PMID

  20. Blast injury research: modeling injury effects of landmines, bullets, and bombs.

    PubMed

    Hayda, Roman; Harris, Robert M; Bass, Cameron Dale

    2004-05-01

    Terrorist blasts and landmine injuries have become more common in the past several decades generating thousands of casualties. Preventive and prognostic measures are limited by the lack of knowledge of these complex events. Previous blast research has focused on primary blast injuries that involve the lung, despite musculoskeletal injuries being the most common. Through the use of instrumented cadavers, Hybrid III test dummies, and other surrogates, unique models of these events have been created. The investigations studied the effectiveness of antimine footwear, forces and injury mechanisms in temporary shelters subjected to blast, modeling of blast-induced glass fragmentation, and helmet deformation and injury potential under ballistic load. Despite blasts being much higher rate events than those seen in automotive blunt trauma, we were able to measure forces and create injury models. We found that antimine footwear will require additional development to be effective. Guidelines for shelter placement have been altered, and tempered glass seems to offer no protection when compared with annealed glass. Although these models are in their nascent phase, the thorough understanding of the biomechanical nature of these blast injuries will assist in developing strategies to reduce injuries and in the creation of forecasting models.

  1. 30 CFR 75.1323 - Blasting circuits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by...

  2. 30 CFR 75.1323 - Blasting circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by...

  3. 30 CFR 75.1323 - Blasting circuits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by...

  4. 30 CFR 75.1323 - Blasting circuits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by...

  5. 30 CFR 75.1323 - Blasting circuits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made by...

  6. 29 CFR 1926.912 - Underwater blasting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Underwater blasting. 1926.912 Section 1926.912 Labor... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... swimming or diving operations are in progress in the vicinity of the blasting area. If such operations are...

  7. 29 CFR 1926.912 - Underwater blasting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Underwater blasting. 1926.912 Section 1926.912 Labor... Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired without... swimming or diving operations are in progress in the vicinity of the blasting area. If such operations are...

  8. Domain enhanced lookup time accelerated BLAST.

    PubMed

    Boratyn, Grzegorz M; Schäffer, Alejandro A; Agarwala, Richa; Altschul, Stephen F; Lipman, David J; Madden, Thomas L

    2012-04-17

    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. 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. 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.

  9. Identification of blast resistance genes for managing rice blast disease

    USDA-ARS?s Scientific Manuscript database

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating diseases worldwide. In the present study, an international set of monogenic differentials carrying 24 major blast resistance (R) genes (Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit, Pita, Pita2,...

  10. Treatment of infected soft tissue blast injury in swine by regulated negative pressure wound therapy.

    PubMed

    Li, Jinqing; Topaz, Morris; Tan, Hong; Li, Yuejun; Li, Wangzhou; Xun, Wenxing; Yuan, Yanqin; Chen, Shaozong; Li, Xueyong

    2013-02-01

    This study was designed to investigate the therapeutic potential of regulated negative pressure wound therapy (RNPT) in treating infected blast injuries in swine. Approximately 30% to 80% of blast injuries develop infection, which increases the morbidity and mortality of these casualties. RNPT has been used in US military operations in Iraq; however, no randomized controlled study has been conducted on the use of RNPT to treat infected war injuries. Infected soft tissue blast injuries were treated with gauze dressings or RNPT with different pressures ranging from -5 to -35 kPa. To evaluate the wound healing process, the wound area, wound depth, the number of proliferative cells, and the vascular endothelial cells in the granulation tissue were measured at different time points. Furthermore, to evaluate the infection and inflammation of the blast injury, the bacterial load, bacterial species, and several inflammatory markers were detected. Compared with gauze dressing treatments, RNPT reduced bacterial load more efficiently, initiated granulation tissue formation earlier, and increased the inflammation faster. Negative pressures ranging from -10 to -25 kPa applied on the RNPT group showed beneficial effects in treating the infected soft tissue blast injury. RNPT did not significantly change both the aerobic and anaerobic bacterial composition compared with those of the gauze dressing group. RNPT clearly shows beneficial effects in treating the infected soft tissue blast injury in comparison with the gauze dressing therapy in swine.

  11. Computer assisted blast design and assessment tools

    SciTech Connect

    Cameron, A.R.; Kleine, T.H.; Forsyth, W.W.

    1995-12-31

    In general the software required by a blast designer includes tools that graphically present blast designs (surface and underground), can analyze a design or predict its result, and can assess blasting results. As computers develop and computer literacy continues to rise the development of and use of such tools will spread. An example of the tools that are becoming available includes: Automatic blast pattern generation and underground ring design; blast design evaluation in terms of explosive distribution and detonation simulation; fragmentation prediction; blast vibration prediction and minimization; blast monitoring for assessment of dynamic performance; vibration measurement, display and signal processing; evaluation of blast results in terms of fragmentation; and risk and reliability based blast assessment. The authors have identified a set of criteria that are essential in choosing appropriate software blasting tools.

  12. Soil Liquefaction Resulting from Blast-Induced Spherical Stress Waves

    DTIC Science & Technology

    1990-01-01

    on vibration sensitive. two phase materials like loose saturated sands, there can be elastic strain in the water phase but plastic strain in the sand...similar behaviour. Liquefaction can be induced by a variety of loading menhanisms including monotonic stress changes, earthquakes, and blast vibrations ...A sandstone bedrock is estimated to lie between 8 and 9 m below the ground surface with a series of folded shale layers over the sandstone. The top

  13. Mild blast events alter anxiety, memory, and neural activity patterns in the anterior cingulate cortex.

    PubMed

    Xie, Kun; Kuang, Hui; Tsien, Joe Z

    2013-01-01

    There is a general interest in understanding of whether and how exposure to emotionally traumatizing events can alter memory function and anxiety behaviors. Here we have developed a novel laboratory-version of mild blast exposure comprised of high decibel bomb explosion sound coupled with strong air blast to mice. This model allows us to isolate the effects of emotionally fearful components from those of traumatic brain injury or bodily injury typical associated with bomb blasts. We demonstrate that this mild blast exposure is capable of impairing object recognition memory, increasing anxiety in elevated O-maze test, and resulting contextual generalization. Our in vivo neural ensemble recording reveal that such mild blast exposures produced diverse firing changes in the anterior cingulate cortex, a region processing emotional memory and inhibitory control. Moreover, we show that these real-time neural ensemble patterns underwent post-event reverberations, indicating rapid consolidation of those fearful experiences. Identification of blast-induced neural activity changes in the frontal brain may allow us to better understand how mild blast experiences result in abnormal changes in memory functions and excessive fear generalization related to post-traumatic stress disorder.

  14. An investigation of a reticulated foam - perforated steel sheet combination as a blast mitigation structure

    NASA Astrophysics Data System (ADS)

    Nguyen, Thuy-Tien N.; Proud, William G.

    2017-01-01

    Explosions are one of the main causes of injuries during battles and conflicts, with improvised explosive devices (IEDs) becoming increasingly common. Blast waves produced from such explosions can inflict very complex injuries on human and serious damage to structures. Here, the interaction between blast waves and sandwich structures of reticulated foam and perforated sheets is studied using a shock tube. The level of mitigation for primary blast injuries of these structures are discussed in terms of pulse shape, pressure magnitude and impulse. Schlieren photography and other high-speed imaging were used to capture the form of the blast wave. The results show up to 95% mitigation in both pressure and impulse with the structures studied. The behaviors of these mitigating sandwich panels under two loadings, Mach 2.0 and Mach 2.6, are also discussed.

  15. Theta blast cell

    SciTech Connect

    Mc Carthy, W.W.

    1987-04-28

    An underground nuclear blast shelter is described comprising: cell means below ground level containing living space for one or more occupants of the shelter; underground command station means separated vertically and horizontally from the cell means having a dome at ground surface for providing access to the shelter, the dome being the only visible portion of the shelter; means for providing communication between the command station means and the cell means including a vertical hollow shaft extending down from the command station means and a horizontal hollow shaft connecting the vertical shaft to the cell means; the command station means including hatch means in the dome to provide the access and means for discharging waste products from the shelter; and flexing means in the vertical shaft to absorb a downward blast force on the dome.

  16. Reactive Blast Waves from Composite Charges

    SciTech Connect

    Kuhl, A L; Bell, J B; Beckner, V E

    2009-10-16

    Investigated here is the performance of composite explosives - measured in terms of the blast wave they drive into the surrounding environment. The composite charge configuration studied here was a spherical booster (1/3 charge mass), surrounded by aluminum (Al) powder (2/3 charge mass) at an initial density of {rho}{sub 0} = 0.604 g/cc. The Al powder acts as a fuel but does not detonate - thereby providing an extreme example of a 'non-ideal' explosive (where 2/3 of the charge does not detonate). Detonation of the booster charge creates a blast wave that disperses the Al powder and ignites the ensuing Al-air mixture - thereby forming a two-phase combustion cloud embedded in the explosion. Afterburning of the booster detonation products with air also enhances and promotes the Al-air combustion process. Pressure waves from such reactive blast waves have been measured in bomb calorimeter experiments. Here we describe numerical simulations of those experiments. A Heterogeneous Continuum Model was used to model the dispersion and combustion of the Al particle cloud. It combines the gasdynamic conservation laws for the gas phase with a dilute continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models of Khasainov. It incorporates a combustion model based on mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Adaptive Mesh Refinement (AMR) was used to capture the energy-bearing scales of the turbulent flow on the computational grid, and to track

  17. NCBI BLAST: a better web interface.

    PubMed

    Johnson, Mark; Zaretskaya, Irena; Raytselis, Yan; Merezhuk, Yuri; McGinnis, Scott; Madden, Thomas L

    2008-07-01

    Basic Local Alignment Search Tool (BLAST) is a sequence similarity search program. The public interface of BLAST, http://www.ncbi.nlm.nih.gov/blast, at the NCBI website has recently been reengineered to improve usability and performance. Key new features include simplified search forms, improved navigation, a list of recent BLAST results, saved search strategies and a documentation directory. Here, we describe the BLAST web application's new features, explain design decisions and outline plans for future improvement.

  18. Blast furnace injection symposium: Proceedings

    SciTech Connect

    1996-12-31

    These proceedings contain 14 papers related to blast furnace injection issues. Topics include coal quality, coal grinding, natural gas injection, stable operation of the blast furnace, oxygen enrichment, coal conveying, and performance at several steel companies. All papers have been processed separately for inclusion on the data base.

  19. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    SciTech Connect

    Dr. M.A. Ebadian

    2000-01-13

    The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process.

  20. Performance of blasting caps

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J. (Inventor); Schimmel, Morry L. (Inventor); Perry, Ronnie B. (Inventor)

    1993-01-01

    Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.

  1. Numerical investigation of the effects of shock tube geometry on the propagation of an ideal blast wave profile

    NASA Astrophysics Data System (ADS)

    Li, X. D.; Hu, Z. M.; Jiang, Z. L.

    2017-03-01

    Bio-shock tubes (BSTs) can approximately simulate the typical blast waves produced by nuclear or chemical charge explosions for use in biological damage studies. The profile of an ideal blast wave in air is characterized by the overpressure, the negative pressure, and the positive pressure duration, which are determined by the geometric configurations of BSTs. Numerical experiments are carried out using the Eulerian equations by the dispersion-controlled dissipative scheme to investigate the effect of different structural components on ideal blast waveforms. The results show that cylindrical and conical frustum driver sections with an appropriate length can produce typical blast wave profiles, but a flattened peak pressure may appear when using a tube of a longer length. Neither a double-expansion tube nor a shrinkage tube set in BSTs is practical for the production of an ideal blast waveform. In addition, negative pressure recovery will occur, exceeding the ambient pressure with an increase in pressure in the vacuum section.

  2. Numerical investigation of the effects of shock tube geometry on the propagation of an ideal blast wave profile

    NASA Astrophysics Data System (ADS)

    Li, X. D.; Hu, Z. M.; Jiang, Z. L.

    2017-09-01

    Bio-shock tubes (BSTs) can approximately simulate the typical blast waves produced by nuclear or chemical charge explosions for use in biological damage studies. The profile of an ideal blast wave in air is characterized by the overpressure, the negative pressure, and the positive pressure duration, which are determined by the geometric configurations of BSTs. Numerical experiments are carried out using the Eulerian equations by the dispersion-controlled dissipative scheme to investigate the effect of different structural components on ideal blast waveforms. The results show that cylindrical and conical frustum driver sections with an appropriate length can produce typical blast wave profiles, but a flattened peak pressure may appear when using a tube of a longer length. Neither a double-expansion tube nor a shrinkage tube set in BSTs is practical for the production of an ideal blast waveform. In addition, negative pressure recovery will occur, exceeding the ambient pressure with an increase in pressure in the vacuum section.

  3. Laboratory Simulation of Response to a Distributed Pressure Load

    SciTech Connect

    Mayes, R.; Simmermacher, T.

    1998-10-21

    Responses to a distributed pressure load are typically predicted through the use of a finite-element model. This procedure depends on the model to represent the actual structure accurately. Another technique that is developed in this work is to predict the response based upon an experi- mentally derived model. This model consists of frequency response functions. The pressure distribution is assumed to be known. In this work, the pressure load will be a blast load. The focus of this work will be to simulate a harsh, shock-like environment. Data from a reverse Hopkinson bar (RHB) test is used to generate the response to a symmetric, distributed load. The reverse Hopkinson bar generates a high ampli- tude, high frequency content pulse that excites components at near-blast levels. The frequency response functions gen- erated from the RHB are used to generate an experimental model of the structure, which is then used in conjunction with the known pressure distribution, to estimate the component response to a blast. This result can then be used with a model correlation technique to adjust a finite element model such that data from a true blast test can be used to only fine tune the model. This work details the estimation response due to the blast.

  4. Desert dust contribution to PM10 loads in Italy: Methods and recommendations addressing the relevant European Commission Guidelines in support to the Air Quality Directive 2008/50

    NASA Astrophysics Data System (ADS)

    Barnaba, Francesca; Bolignano, Andrea; Di Liberto, Luca; Morelli, Matteo; Lucarelli, Franco; Nava, Silvia; Perrino, Cinzia; Canepari, Silvia; Basart, Sara; Costabile, Francesca; Dionisi, Davide; Ciampichetti, Spartaco; Sozzi, Roberto; Gobbi, Gian Paolo

    2017-07-01

    In 2011 the European Commission (EC) released specific 'Guidelines' describing the methods to quantify and subtract the contribution of natural sources from the PM10 values regulated by the European Air Quality Directive (2008/50/EC). This work investigates the applicability to Italy of the EC-Methodology suggested for desert-dust, describes main limitations encountered and proposes specific modifications embedded within a 'revised-Methodology' to extend/improve its use. The revised-Methodology capabilities are evaluated using original, chemically-resolved mineral-dust mass concentration measurements, showing better performances in predicting timing and absolute values of the desert-dust contribution to the daily-PM10 with respect to the current EC-approach. The revised-Methodology is then translated into an automatic (user-independent) tool tailored to the expected final-users. This tool is applied over Central Italy across a 3-year long period (2012-2014), and over the whole Italian country for a calendar year (2012). The derived results confirm and extend to Italian regions never addressed before some previously observed features of the desert-dust impact over the country, such as a clear latitudinal dependence of the desert-dust impact on the yearly average PM10 (from more than 5 μg/m3 to less than 0.5 μg/m3, going from south to north Italy). The modifications introduced within the revised-Methodology also suggest a non-negligible role of desert-dust resuspension in areas characterized by both high traffic levels and soil sealing (urban areas and along the major Italian routes). In the Rome area, such an effect is found to add a contribution of about 2 μg/m3 (i.e., of 20%) to the mean desert-dust load per dust day (about 10 μg/m3). At the national level, this effect contributes increasing the total number of desert-dust-driven exceedances of the PM10 daily limit value even in the northern regions, where the desert-dust impact on the PM10 yearly average is

  5. Circulation in blast driven instabilities

    NASA Astrophysics Data System (ADS)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  6. NCBI BLAST+ integrated into Galaxy.

    PubMed

    Cock, Peter J A; Chilton, John M; Grüning, Björn; Johnson, James E; Soranzo, Nicola

    2015-01-01

    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. The command line NCBI BLAST+ tool suite was wrapped for use within Galaxy. Appropriate datatypes were defined as needed. The integration of the BLAST+ tool suite into Galaxy has the goal of making common BLAST tasks easy and advanced tasks possible. This project is an informal international collaborative effort, and is deployed and used on Galaxy servers worldwide. Several examples of applications are described here.

  7. Assessment of the Effect of Blast Hole Diameter on the Number of Oversize Boulders Using ANN Model

    NASA Astrophysics Data System (ADS)

    Dhekne, Prakash; Pradhan, Manoj; Jade, Ravi Krishnarao

    2016-04-01

    Now-a-days, blasts are planned using large diameter blast holes. The loading density (kg/m) and subsequently the energy available for the breakage of the rockmass increase with the diameter. The in-hole velocity of detonation (VoD) of non-ideal explosive also boosts up with the increase in diameter till the optimum diameter is reached. The increase in the energy content and in-hole VoD cause a sizable effect on the rock fragmentation. The effect can be assessed by counting the number of oversize boulders. This paper explains as to how the technique of artificial neural network modeling was used to predict the number of oversize boulders resulting from ANFO and SME blasts with blast holes of different diameters. The results from ANFO blasts indicated that there was no significant variation in the number of oversize boulders with the diameter whereas a perceptible variation was noticed in case of SME blasts with the change in the diameter. The change in the number of oversize boulders in ANFO blasts was negligible because mean energy factor remained almost same even when the diameter of the blast holes was altered. The decrease in the number of oversize boulders in SME blasts was on account of increase in mean energy factor when the blast hole diameter was increased. The increase in the in-hole VoD due to increase in the diameter of the hole was not found to have an effect on the generation of oversize boulders as this increase was not substantial both in SME and ANFO blasts.

  8. Discrete fiber-reinforced polyurea systems for infrastructure strengthening and blast mitigation

    NASA Astrophysics Data System (ADS)

    Carey, Natalia L.

    The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation. The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon tensile testing. The addition of glass fiber to a polymer coating provided improved stiffness and strength to the composite system while the polyurea base material provided ductility. The second paper evaluated the behavior of hybrid, plain, and steel fiber-reinforced concrete panels coated with various polyurea and DFRP systems under blast loading. Hybrid panels demonstrated higher blast mitigation performance compared to plain and steel fiber-reinforced concrete panels due to sacrificial hybrid layer. The addition of plain polyurea or DFRP systems on the tension side improved panel performance by containing fragmentation during a blast event. The third paper presents an analytical investigation conducted using the explicit finite element program LS-DYNA to model panel and coating response under blast loading. Several modeling solutions were undertaken and compared for concrete formulation. Modeling results were analyzed and compared to the experimental work to validate the conclusions. The final paper describes an internal equilibrium mechanics based model developed to predict the flexural capacity of reinforced concrete beams strengthened with various DFRP systems. The developed model was validated using

  9. Studies on blast traumatic brain injury using in-vitro model with shock tube.

    PubMed

    Arun, Peethambaran; Spadaro, John; John, Jennifer; Gharavi, Robert B; Bentley, Timothy B; Nambiar, Madhusoodana P

    2011-06-11

    One of the major limitations in studying the mechanisms of blast-induced traumatic brain injury (bTBI) or screening therapeutics for protection is the lack of suitable laboratory model systems that can closely mimic the complex blast exposure. Although animal models of bTBI that use shock tubes to mimic blast exposure are available, no high throughput shock tube-based in-vitro models have been reported. Here, we report an in-vitro bTBI model using a compressed air-driven shock tube and mouse neuroblastoma/rat glioblastoma hybrid cells (NG108-15) or SH-SY5Y human neuroblastoma cells in tissue culture plates. Our data showed significant neurobiological effects with decreased adenosine triphosphate levels, increased cellular injury, lactate dehydrogenase release, and reactive oxygen species formation after blast exposure.

  10. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier for...

  11. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier for...

  12. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier for...

  13. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier for...

  14. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier for...

  15. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    SciTech Connect

    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

  16. Repeat low-level blast exposure increases transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1) expression in the trigeminal ganglion

    PubMed Central

    Burke, Teresa A.; Doyle Brackley, Allison; Jeske, Nathaniel A.; Cleland, Jeffery M.; Lund, Brian J.

    2017-01-01

    Blast-associated sensory and cognitive trauma sustained by military service members is an area of extensively studied research. Recent studies in our laboratory have revealed that low-level blast exposure increased expression of transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1), proteins well characterized for their role in mediating pain transmission, in the cornea. Determining the functional consequences of these alterations in protein expression is critical to understanding blast-related sensory trauma. Thus, the purpose of this study was to examine TRPV1 and ET-1 expression in ocular associated sensory tissues following primary and tertiary blast. A rodent model of blast injury was used in which anesthetized animals, unrestrained or restrained, received a single or repeat blast (73.8 ± 5.5 kPa) from a compressed air shock tube once or daily for five consecutive days, respectively. Behavioral and functional analyses were conducted to assess blast effects on nocifensive behavior and TRPV1 activity. Immunohistochemistry and Western Blot were also performed with trigeminal ganglia (TG) to determine TRPV1, ET-1 and glial fibrillary associated protein (GFAP) expression following blast. Increased TRPV1, ET-1 and GFAP were detected in the TG of animals exposed to repeat blast. Increased nocifensive responses were also observed in animals exposed to repeat, tertiary blast as compared to single blast and control. Moreover, decreased TRPV1 desensitization was observed in TG neurons exposed to repeat blast. Repeat, tertiary blast resulted in increased TRPV1, ET-1 and GFAP expression in the TG, enhanced nociception and decreased TRPV1 desensitization. PMID:28797041

  17. Repeat low-level blast exposure increases transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1) expression in the trigeminal ganglion.

    PubMed

    Por, Elaine D; Sandoval, Melody L; Thomas-Benson, Chiquita; Burke, Teresa A; Doyle Brackley, Allison; Jeske, Nathaniel A; Cleland, Jeffery M; Lund, Brian J

    2017-01-01

    Blast-associated sensory and cognitive trauma sustained by military service members is an area of extensively studied research. Recent studies in our laboratory have revealed that low-level blast exposure increased expression of transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1), proteins well characterized for their role in mediating pain transmission, in the cornea. Determining the functional consequences of these alterations in protein expression is critical to understanding blast-related sensory trauma. Thus, the purpose of this study was to examine TRPV1 and ET-1 expression in ocular associated sensory tissues following primary and tertiary blast. A rodent model of blast injury was used in which anesthetized animals, unrestrained or restrained, received a single or repeat blast (73.8 ± 5.5 kPa) from a compressed air shock tube once or daily for five consecutive days, respectively. Behavioral and functional analyses were conducted to assess blast effects on nocifensive behavior and TRPV1 activity. Immunohistochemistry and Western Blot were also performed with trigeminal ganglia (TG) to determine TRPV1, ET-1 and glial fibrillary associated protein (GFAP) expression following blast. Increased TRPV1, ET-1 and GFAP were detected in the TG of animals exposed to repeat blast. Increased nocifensive responses were also observed in animals exposed to repeat, tertiary blast as compared to single blast and control. Moreover, decreased TRPV1 desensitization was observed in TG neurons exposed to repeat blast. Repeat, tertiary blast resulted in increased TRPV1, ET-1 and GFAP expression in the TG, enhanced nociception and decreased TRPV1 desensitization.

  18. Coal combustion under conditions of blast furnace injection. Final technical report, September 1, 1992--August 31, 1993

    SciTech Connect

    Crelling, J.C.; Case, E.R.

    1993-12-31

    A potentially new use for Illinois coal is as a fuel injected into a blast furnace to produce molten iron as the first step in steel production. Because of its increasing cost and decreasing availability, metallurgical coke is now being replaced by coal injected at the tuyere area of the furnace where the blast air enters. The purpose of this study is to evaluate the combustion of coal during the blast furnace injection process and to delineate the optimum properties of the feed coal. This investigation is significant to the use of Illinois coal in that the limited research to date suggests that coals of low fluidity and moderate to high sulfur and chlorine contents are suitable feedstocks for blast furnace injection. During the first phase of this project a number of the objectives were realized, specifically: (1) a blast furnace sampling system was developed and used successfully to collect samples inside an active furnace; (2) two sets of blast furnace samples were collected and petrographic analysis showed that char derived from injected coal is entering the reduction zone of the furnace; (3) a coal/char sampling probe was designed and fabricated; (4) the completion of a program of reactivity experiments on the injected coal char, blast furnace coke and Herrin No. 6 char. The results of the reactivity experiments indicate that Herrin No. 6 coal is similar or even superior to coals now being used in blast furnace injection and that additional testing is warranted.

  19. A dynamic simulation of a lead blast furnace

    NASA Astrophysics Data System (ADS)

    Chao, John T.

    1981-06-01

    A dynamic model has been developed to simulate the operation of the stack zone of a lead blast furnace. The mathematical formulation of the governing equations of change leads to a system of 2nd order partial differential equations, which is solved by finite difference methods. A reduction model of ash-layer diffusion controlled mechanism, which allows the stepwise reduction to the lowest oxide or metal thermodynamically possible for the local gas composition within the sinter, is employed in this model. The surface reaction and the internal diffusion in the porous solid particles are taken into account in the coke gasification reaction. The profiles of the temperatures of gases and solids, solid compositions, and gas compositions and pressure in both radial and axial directions are predicted by the model. The results provide a good representation of the experimental data obtained for the blast furnace at Brunswick Mining and Smelting Corp., Ltd., New Brunswick, Canada and also of the less extensive data available for the Cominco blast furnace at Trail, British Columbia, Canada. In addition to the modelling of the stack, a mass and energy balance for the bosh zone is also included in the present calculation. The improvement of coke efficiency due to oxygen enrichment in the blast air for the Brunswick Furnace were interpreted semiquantitatively. The effect of sinter size distribution on the furnace performance has also been studied.

  20. Zinc-lead blast furnace—the key developments

    NASA Astrophysics Data System (ADS)

    Temple, Derek

    1980-09-01

    Because of his close association with the zinc-lead blast furnace process, the author has chosen to draw on this source to examine some key metallurgical advances. In addition to discussing the importance of some of these developments in the context of the zinc-lead blast furnace, comment is made on the more general role of the blast furnace technique in nonferrous extractive metallurgy. Naturally, the lead splash condenser system, without which the zinc-lead blast furnace would never have operated, occupies first place. The development of lead cooling launders is considered after discussion of the adoption of top air additions to minimize the reoxidation of zinc vapor in its passage from the furnace charge to the condenser. Without these two improvements on the original concept large capacity plants could not have been built. In addition, the development of the updraft technique of zinc-lead sinter production is examined; without this operating costs would have been excessive and expansion of the process would have ceased.

  1. Neurological Effects of Blast Injury

    PubMed Central

    Hicks, Ramona R.; Fertig, Stephanie J.; Desrocher, Rebecca E.; Koroshetz, Walter J.; Pancrazio, Joseph J.

    2010-01-01

    Over the last few years, thousands of soldiers and an even greater number of civilians have suffered traumatic injuries due to blast exposure, largely attributed to improvised explosive devices in terrorist and insurgent activities. The use of body armor is allowing soldiers to survive blasts that would otherwise be fatal due to systemic damage. Emerging evidence suggests that exposure to a blast can produce neurological consequences in the brain, but much remains unknown. To elucidate the current scientific basis for understanding blast-induced traumatic brain injury (bTBI), the NIH convened a workshop in April, 2008. A multidisciplinary group of neuroscientists, engineers, and clinicians were invited to share insights on bTBI, specifically pertaining to: physics of blast explosions, acute clinical observations and treatments, preclinical and computational models, and lessons from the international community on civilian exposures. This report provides an overview of the state of scientific knowledge of bTBI, drawing from the published literature, as well as presentations, discussions, and recommendations from the workshop. One of the major recommendations from the workshop was the need to characterize the effects of blast exposure on clinical neuropathology. Clearer understanding of the human neuropathology would enable validation of preclinical and computational models, which are attempting to simulate blast wave interactions with the central nervous system. Furthermore, the civilian experience with bTBI suggests that polytrauma models incorporating both brain and lung injuries may be more relevant to the study of civilian countermeasures than considering models with a neurological focus alone. PMID:20453776

  2. A definition of criteria required to evaluate the results of production blasts

    SciTech Connect

    Martineau, N.; Tienkamp, N.

    1996-12-01

    Through the normal course of operation, mine operators are living situations where blast results need to be measured. It becomes the supervisory group responsibility to select evaluation parameters with appropriated and available techniques. In Mine Selbaie`s case, the authors have selected the following parameters: rock fragmentation, oversize fragments, rock pile movement, grade rupture. It is understandable that each parameter does not have the same influence in a global blast evaluation. To rate the parameters, the authors estimate their influence in relation with the potential cost per ton in different phases of the operations such as: truck loading factor, truck loading time, operation overall efficiency, secondary drilling and blasting, energy consumption at the gyratory crusher. The conference objectives are to outline and define the parameters and their related importance with associated operating cost. As well, this same parameter formula will be used to compare the performance between ANFO and high density mini-prill ANFO product.

  3. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  4. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  5. Method and device for optimizing the air-fuel mixture burn rate of internal combustion engines during low speed, light and heavy load operating conditions

    SciTech Connect

    Burandt, C.O.

    1990-10-09

    This patent describes a method for optimizing low speed light load and low speed heavy load operating conditions in an internal combustion engine. The engine has a camshaft, a crankshaft, at least one intake valve and at least one piston, and is capable of providing for small valve events, and the engine providing for earlier than normal intake valve closings the method comprises: sensing the load demand on the engine, regulating the phasing of the operation of the camshaft of the engine with the operation of the crankshaft of the engine in response to the sensed load demand by advancing the operation of camshaft relative to the operation of the crankshaft when a heavy load demand is sensed and by retarding the operation of the camshaft relative to the operation of the crankshaft when alight load demand is sensed, and sensing detonation in the engine and regulating the phasing operation of the camshaft relative to the operation of the crankshaft by advancing the operation of the camshaft relative to the crankshaft when detonation is sensed.

  6. Evaluation of Novel Polyunsaturated Fatty Acid Derived Lipid Mediators of Inflammation to Ameliorate the Deleterious Effects of Blast Over Pressure on Eye and Brain Visual Processing Centers in Rats

    DTIC Science & Technology

    2015-08-01

    Ameliorate the Deleterious Effects of Blast Over Pressure on Eye and Brain Visual Processing Centers in Rats PRINCIPAL INVESTIGATOR: Dr. James DeMar...Novel Polyunsaturated Fatty Acid Derived Lipid Mediators of Sb. GRANT NUMBER Inflammation to Ameliorate the Deleterious Effects of Blast Over Pressure on...compressed air driven shock tube and exposing them, in a right side on orientation, once to a 20 psi (260Hz) blast over pressure wave. Rats were assessed at

  7. Placement of the dam for the no. 2 kambaratinskaya HPP by large-scale blasting: some observations

    SciTech Connect

    Shuifer, M. I.; Argal, E. S.

    2011-11-15

    Results of complex instrument observations of large-scale blasting during construction of the dam for the No. 2 Kambaratinskaya HPP on the Naryn River in the Republic of Kirgizia are analyzed. The purpose of these observations was: to determine the actual parameters of the seismic process, evaluate the effect of air and acoustic shock waves, and investigate the kinematics of the surface formed by the blast in its core region within the mass of fractured rocks.

  8. Noise and blast

    NASA Technical Reports Server (NTRS)

    Hodge, D. C.; Garinther, G. R.

    1973-01-01

    Noise and blast environments are described, providing a definition of units and techniques of noise measurement and giving representative booster-launch and spacecraft noise data. The effects of noise on hearing sensitivity and performance are reviewed, and community response to noise exposure is discussed. Physiological, or nonauditory, effects of noise exposure are also treated, as are design criteria and methods for minimizing the noise effects of hearing sensitivity and communications. The low level sound detection and speech reception are included, along with subjective and behavioral responses to noise.

  9. Noise and blast

    NASA Technical Reports Server (NTRS)

    Hodge, D. C.; Garinther, G. R.

    1973-01-01

    Noise and blast environments are described, providing a definition of units and techniques of noise measurement and giving representative booster-launch and spacecraft noise data. The effects of noise on hearing sensitivity and performance are reviewed, and community response to noise exposure is discussed. Physiological, or nonauditory, effects of noise exposure are also treated, as are design criteria and methods for minimizing the noise effects of hearing sensitivity and communications. The low level sound detection and speech reception are included, along with subjective and behavioral responses to noise.

  10. Astrophysical blast wave data

    SciTech Connect

    Riley, Nathan; Geissel, Matthias; Lewis, Sean M; Porter, John L.

    2015-03-01

    The data described in this document consist of image files of shadowgraphs of astrophysically relevant laser driven blast waves. Supporting files include Mathematica notebooks containing design calculations, tabulated experimental data and notes, and relevant publications from the open research literature. The data was obtained on the Z-Beamlet laser from July to September 2014. Selected images and calculations will be published as part of a PhD dissertation and in associated publications in the open research literature, with Sandia credited as appropriate. The authors are not aware of any restrictions that could affect the release of the data.

  11. METHODOLOGIES FOR ESTIMATING AIR EMISSIONS FROM THREE NON-TRADITIONAL SOURCE CATEGORIES: OIL SPILLS, PETROLEUM VESSEL LOADING & UNLOADING, AND COOLING TOWERS

    EPA Science Inventory

    The report discusses part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plan (sip) area source methodologies and to develop appropriate emis...

  12. METHODOLOGIES FOR ESTIMATING AIR EMISSIONS FROM THREE NON-TRADITIONAL SOURCE CATEGORIES: OIL SPILLS, PETROLEUM VESSEL LOADING & UNLOADING, AND COOLING TOWERS

    EPA Science Inventory

    The report discusses part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plan (sip) area source methodologies and to develop appropriate emis...

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

    PubMed Central

    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

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

    PubMed

    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

  15. Development and application of a method for predicting rotor free wake positions and resulting rotor blade air loads. Volume 1: Model and results

    NASA Technical Reports Server (NTRS)

    Sadler, S. G.

    1971-01-01

    Rotor wake geometries are predicted by a process similar to the startup of a rotor in a free stream. An array of discrete trailing and shed vortices is generated with vortex strengths corresponding to stepwise radial and azimuthal blade circulations. The array of shed and trailing vortices is limited to an arbitrary number of azimuthal steps behind each blade. The remainder of the wake model of each blade is an arbitrary number of trailing vortices. Vortex element end points were allowed to be transported by the resultant velocity of the free stream and vortex-induced velocities. Wake geometry, wake flow, and wake-induced velocity influence coefficients are generated by this program for use in the blade loads portion of the calculations. Blade loads computations include the effects of nonuniform inflow due to a free wake, nonlinear airfoil characteristics, and response of flexible blades to the applied loads. Computed wake flows and blade loads are compared with experimentally measured data. Predicted blade loads, response and shears and moments are obtained for a model rotor system having two independent rotors. The effects of advance ratio, vertical separation of rotors, different blade radius ratios, and different azimuthal spacing of the blades of one rotor with respect to the other are investigated.

  16. Quarry blasts assessment and their environmental impacts on the nearby oil pipelines, southeast of Helwan City, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Adel M. E.; Mohamed, Abuo El-Ela A.

    2013-06-01

    Ground vibrations induced by blasting in the cement quarries are one of the fundamental problems in the quarrying industry and may cause severe damage to the nearby utilities and pipelines. Therefore, a vibration control study plays an important role in the minimization of environmental effects of blasting in quarries. The current paper presents the influence of the quarry blasts at the National Cement Company (NCC) on the two oil pipelines of SUMED Company southeast of Helwan City, by measuring the ground vibrations in terms of Peak Particle Velocity (PPV). The seismic refraction for compressional waves deduced from the shallow seismic survey and the shear wave velocity obtained from the Multi channel Analysis of Surface Waves (MASW) technique are used to evaluate the closest site of the two pipelines to the quarry blasts. The results demonstrate that, the closest site of the two pipelines is of class B, according to the National Earthquake Hazard Reduction Program (NEHRP) classification and the safe distance to avoid any environmental effects is 650 m, following the deduced Peak Particle Velocity (PPV) and scaled distance (SD) relationship (PPV = 700.08 × SD-1.225) in mm/s and the Air over Pressure (air blast) formula (air blast = 170.23 × SD-0.071) in dB. In the light of prediction analysis, the maximum allowable charge weight per delay was found to be 591 kg with damage criterion of 12.5 mm/s at the closest site of the SUMED pipelines.

  17. Coal combustion under conditions of blast furnace injection. [Quarterly] technical report, 1 March 1993--31 May 1993

    SciTech Connect

    Crelling, J.C.; Case, E.R.

    1993-09-01

    A potentially new use for Illinois coal is its use as a fuel injected into a blast furnace to produce molten iron as the first step in steel production. Because of its increasing cost and decreasing availability, metallurgical coke is now being replaced by coal injected at the tuyere area of the furnace where the blast air enters. The purpose of this study is to evaluate the combustion of coal during the blast furnace injection process and to delineate the optimum properties of the feed coal. The basic program is designed to determine the reactivity of both coal and its derived char under blast furnace conditions and to compare the results to similar properties of blast furnace coke. The results of the first two experiments in which coal char pyrolyzed in nitrogen at 1000{degrees}C in an EPR were reacted isothermally in air at 1000{degrees}C and 1200{degrees}C. The reactivity values of the same char in these two experiments were different by an order of magnitude. The char reactivity at 1000{degrees}C was 9.7 {times} 10{sup {minus}4} grams per minute while the reactivity. of the char at 1200{degrees}C was 1.6 {times} 10{sup {minus}3} grams per minute. These results suggest that the temperature of the blast air in the tuyere may be critical in achieving complete carbon burnout.

  18. Damage Evolution and Life Prediction of Cross-Ply C/SiC Ceramic-Matrix Composite under Cyclic Fatigue Loading at Room Temperature and 800 °C in Air

    PubMed Central

    Li, Longbiao

    2015-01-01

    The damage evolution and life prediction of cross-ply C/SiC ceramic-matrix composite (CMC) under cyclic-fatigue loading at room temperature and 800 °C in air have been investigated using damage parameters derived from fatigue hysteresis loops, i.e., fatigue hysteresis modulus and fatigue hysteresis loss energy. The experimental fatigue hysteresis modulus and fatigue hysteresis loss energy degrade with increasing applied cycles attributed to transverse cracks in the 90° plies, matrix cracks and fiber/matrix interface debonding in the 0° plies, interface wear at room temperature, and interface and carbon fibers oxidation at 800 °C in air. The relationships between fatigue hysteresis loops, fatigue hysteresis modulus and fatigue hysteresis loss energy have been established. Comparing experimental fatigue hysteresis loss energy with theoretical computational values, the fiber/matrix interface shear stress corresponding to different cycle numbers has been estimated. It was found that the degradation rate at 800 °C in air is much faster than that at room temperature due to serious oxidation in the pyrolytic carbon (PyC) interphase and carbon fibers. Combining the fiber fracture model with the interface shear stress degradation model and the fibers strength degradation model, the fraction of broken fibers versus the cycle number can be determined for different fatigue peak stresses. The fatigue life S-N curves of cross-ply C/SiC composite at room temperature and 800 °C in air have been predicted. PMID:28793728

  19. Damage Evolution and Life Prediction of Cross-Ply C/SiC Ceramic-Matrix Composite under Cyclic Fatigue Loading at Room Temperature and 800 °C in Air.

    PubMed

    Li, Longbiao

    2015-12-09

    The damage evolution and life prediction of cross-ply C/SiC ceramic-matrix composite (CMC) under cyclic-fatigue loading at room temperature and 800 °C in air have been investigated using damage parameters derived from fatigue hysteresis loops, i.e., fatigue hysteresis modulus and fatigue hysteresis loss energy. The experimental fatigue hysteresis modulus and fatigue hysteresis loss energy degrade with increasing applied cycles attributed to transverse cracks in the 90° plies, matrix cracks and fiber/matrix interface debonding in the 0° plies, interface wear at room temperature, and interface and carbon fibers oxidation at 800 °C in air. The relationships between fatigue hysteresis loops, fatigue hysteresis modulus and fatigue hysteresis loss energy have been established. Comparing experimental fatigue hysteresis loss energy with theoretical computational values, the fiber/matrix interface shear stress corresponding to different cycle numbers has been estimated. It was found that the degradation rate at 800 °C in air is much faster than that at room temperature due to serious oxidation in the pyrolytic carbon (PyC) interphase and carbon fibers. Combining the fiber fracture model with the interface shear stress degradation model and the fibers strength degradation model, the fraction of broken fibers versus the cycle number can be determined for different fatigue peak stresses. The fatigue life S-N curves of cross-ply C/SiC composite at room temperature and 800 °C in air have been predicted.

  20. 3. DETAIL, 3/4 VIEW OF HOT BLAST STOVE ON TOP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL, 3/4 VIEW OF HOT BLAST STOVE ON TOP OF FURNACE SHOWING CAST-IRON RETORTS AND TURNED HEAD (WHERE RAW MATERIALS WERE LOADED INTO FURNACE). - Nassawango Iron Furnace, Furnace Road, 1.2 miles west of Maryland Route 12, Snow Hill, Worcester County, MD