WorldWideScience

Sample records for biological shock

  1. Heat shock protein 72: release and biological significance during exercise.

    Science.gov (United States)

    Whitham, Martin; Fortes, Matthew Benjamin

    2008-01-01

    The cumulative stressors of exercise manifest themselves at a cellular level by threatening the protein homeostasis of the cell. In these conditions, Heat Shock Proteins (HSP) are synthesised to chaperone mis-folded and denatured proteins. As such, the intracellular HSP response is thought to aid cell survival in the face of otherwise lethal cellular stress. Recently, the inducible isoform of the 70 Kda heat shock protein family, Hsp72 has been detected in the extracellular environment. Furthermore, the release of this protein into the circulation has been shown to occur in response to a range of exercise bouts. The present review summarises the current research on the exercise Hsp72 response, the possible mediators and mechanisms of extracellular (e)Hsp72 release, and the possible biological significance of this systemic response. In particular, the possible role of eHsp72 in the modulation of immunity during exercise is discussed.

  2. Biological effects of tandem shock waves demonstrated on magnetic resonance

    Czech Academy of Sciences Publication Activity Database

    Beneš, J.; Zeman, J.; Poučková, P.; Zadinová, M.; Šunka, Pavel; Lukeš, Petr

    Roč. 113, č. 6 ( 2012 ), s. 335-338 ISSN 0006-9248 R&D Projects: GA ČR GA202/09/1151 Institutional research plan: CEZ:AV0Z20430508 Keywords : electrical discharges in water * focused shock waves * cavitations * tandem shock waves Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.472, year: 2012

  3. Laser Induced Shock Waves and Vaporization in Biological System and Material Science

    National Research Council Canada - National Science Library

    Gerstman, Bernard S

    2008-01-01

    .... We have developed a computational model that allows the calculation of damage resulting from a laser pulse of any duration or energy due to temperature rise, explosive bubble formation, and shock wave production...

  4. Biology of the Heat Shock Response and Protein Chaperones: Budding Yeast (Saccharomyces cerevisiae) as a Model System

    Science.gov (United States)

    Verghese, Jacob; Abrams, Jennifer; Wang, Yanyu

    2012-01-01

    Summary: The eukaryotic heat shock response is an ancient and highly conserved transcriptional program that results in the immediate synthesis of a battery of cytoprotective genes in the presence of thermal and other environmental stresses. Many of these genes encode molecular chaperones, powerful protein remodelers with the capacity to shield, fold, or unfold substrates in a context-dependent manner. The budding yeast Saccharomyces cerevisiae continues to be an invaluable model for driving the discovery of regulatory features of this fundamental stress response. In addition, budding yeast has been an outstanding model system to elucidate the cell biology of protein chaperones and their organization into functional networks. In this review, we evaluate our understanding of the multifaceted response to heat shock. In addition, the chaperone complement of the cytosol is compared to those of mitochondria and the endoplasmic reticulum, organelles with their own unique protein homeostasis milieus. Finally, we examine recent advances in the understanding of the roles of protein chaperones and the heat shock response in pathogenic fungi, which is being accelerated by the wealth of information gained for budding yeast. PMID:22688810

  5. Tandem shock waves in medicine and biology: a review of potential applications and successes

    Czech Academy of Sciences Publication Activity Database

    Lukeš, Petr; Fernández, F.; Gutiérrez-Aceves, J.; Fernández, E.; Alvarez, U.M.; Šunka, Pavel; Loske, A.M.

    2016-01-01

    Roč. 26, č. 1 (2016), s. 1-23 ISSN 0938-1287 Institutional support: RVO:61389021 Keywords : Tandem shock waves * Acoustic cavitation * Clinical applications * Bactericidal effect * Genetic transformation * Cancer treatment Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.107, year: 2016 http://link.springer.com/article/10.1007%2Fs00193-015-0577-0

  6. Heat shock protein 70 kDa: molecular biology, biochemistry, and physiology.

    Science.gov (United States)

    Kiang, J G; Tsokos, G C

    1998-11-01

    Heat shock proteins (HSPs) are detected in all cells, prokaryotic and eukaryotic. In vivo and in vitro studies have shown that various stressors transiently increase production of HSPs as protection against harmful insults. Increased levels of HSPs occur after environmental stresses, infection, normal physiological processes, and gene transfer. Although the mechanisms by which HSPs protect cells are not clearly understood, their expression can be modulated by cell signal transducers, such as changes in intracellular pH, cyclic AMP, Ca2+, Na+, inositol trisphosphate, protein kinase C, and protein phosphatases. Most of the HSPs interact with other proteins in cells and alter their function. These and other protein-protein interactions may mediate the little understood effects of HSPs on various cell functions. In this review, we focus on the structure of the HSP-70 family (HSP-70s), regulation of HSP-70 gene expression, their cytoprotective effects, and the possibility of regulating HSP-70 expression through modulation of signal transduction pathways. The clinical importance and therapeutic potential of HSPs are discussed.

  7. Transcript and hormone analyses reveal the involvement of ABA-signalling, hormone crosstalk and genotype-specific biological processes in cold-shock response in wheat

    Czech Academy of Sciences Publication Activity Database

    Kalapos, S.; Dobrev, Petre; Nagy, T.; Vítámvás, P.; Gyorgyey, J.; Kocsy, G.; Marincs, F.; Galiba, G.

    2016-01-01

    Roč. 253, DEC (2016), s. 86-97 ISSN 0168-9452 Institutional support: RVO:61389030 Keywords : complex phytohormone responses * abscisic-acid biosynthesis * frost-resistance * stress responses * gene-expression * chromosome 5a * triticum-monococcum * regulatory network * basal resistance * abiotic stresses * ABA-Signalling * Carbon metabolism * Freezing-tolerance * Gene ontology * Plant hormones * Short-term cold-shock * Triticum aestivum Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.437, year: 2016

  8. In vitro biological characterization of a novel, synthetic diaryl pyrazole resorcinol class of heat shock protein 90 inhibitors.

    Science.gov (United States)

    Sharp, Swee Y; Boxall, Kathy; Rowlands, Martin; Prodromou, Chrisostomos; Roe, S Mark; Maloney, Alison; Powers, Marissa; Clarke, Paul A; Box, Gary; Sanderson, Sharon; Patterson, Lisa; Matthews, Thomas P; Cheung, Kwai-Ming J; Ball, Karen; Hayes, Angela; Raynaud, Florence; Marais, Richard; Pearl, Laurence; Eccles, Sue; Aherne, Wynne; McDonald, Edward; Workman, Paul

    2007-03-01

    The molecular chaperone heat shock protein 90 (HSP90) has emerged as an exciting molecular target. Derivatives of the natural product geldanamycin, such as 17-allylamino-17-demethoxy-geldanamycin (17-AAG), were the first HSP90 ATPase inhibitors to enter clinical trial. Synthetic small-molecule HSP90 inhibitors have potential advantages. Here, we describe the biological properties of the lead compound of a new class of 3,4-diaryl pyrazole resorcinol HSP90 inhibitor (CCT018159), which we identified by high-throughput screening. CCT018159 inhibited human HSP90beta with comparable potency to 17-AAG and with similar ATP-competitive kinetics. X-ray crystallographic structures of the NH(2)-terminal domain of yeast Hsp90 complexed with CCT018159 or its analogues showed binding properties similar to radicicol. The mean cellular GI(50) value of CCT018159 across a panel of human cancer cell lines, including melanoma, was 5.3 mumol/L. Unlike 17-AAG, the in vitro antitumor activity of the pyrazole resorcinol analogues is independent of NQO1/DT-diaphorase and P-glycoprotein expression. The molecular signature of HSP90 inhibition, comprising increased expression of HSP72 protein and depletion of ERBB2, CDK4, C-RAF, and mutant B-RAF, was shown by Western blotting and quantified by time-resolved fluorescent-Cellisa in human cancer cell lines treated with CCT018159. CCT018159 caused cell cytostasis associated with a G(1) arrest and induced apoptosis. CCT018159 also inhibited key endothelial and tumor cell functions implicated in invasion and angiogenesis. Overall, we have shown that diaryl pyrazole resorcinols exhibited similar cellular properties to 17-AAG with potential advantages (e.g., aqueous solubility, independence from NQO1 and P-glycoprotein). These compounds form the basis for further structure-based optimization to identify more potent inhibitors suitable for clinical development.

  9. Shock absorber

    International Nuclear Information System (INIS)

    Nemeth, J.D.

    1981-01-01

    A shock absorber for the support of piping and components in a nuclear power plant is described. It combines a high degree of stiffness under sudden shocks, e.g. seismic disturbances, with the ability to allow for thermal expansion without resistance when so required. (JIW)

  10. demystifying the shock of shocking

    African Journals Online (AJOL)

    (with a pulse), atrial fibrillation and atrial flutter. The energy dose in cardioversion is less (0.5. - 2 J/kg) than in defibrillation (2 - 4 J/kg). In cardioversion the shock is discharged synchronously with the native R wave of the patient. Without synchronisation,. VF can be induced if a shock is delivered during the refractory period ...

  11. Hypovolemic shock

    Science.gov (United States)

    ... the person's position unless they are in immediate danger. Do not give fluids by mouth. If person ... the patient with shock. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: ...

  12. Shock absorber

    International Nuclear Information System (INIS)

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  13. 29th International Symposium on Shock Waves

    CERN Document Server

    Ranjan, Devesh

    2015-01-01

    This proceedings present the results of the 29th International Symposium on Shock Waves (ISSW29) which was held in Madison, Wisconsin, U.S.A., from July 14 to July 19, 2013. It was organized by the Wisconsin Shock Tube Laboratory, which is part of the College of Engineering of the University of Wisconsin-Madison. The ISSW29 focused on the following areas: Blast Waves, Chemically Reactive Flows, Detonation and Combustion,  Facilities, Flow Visualization, Hypersonic Flow, Ignition, Impact and Compaction, Industrial Applications, Magnetohydrodynamics, Medical and Biological Applications, Nozzle Flow, Numerical Methods, Plasmas, Propulsion, Richtmyer-Meshkov Instability, Shock-Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shock Waves in Condensed Matter, Shock Waves in Multiphase Flow, as well as Shock Waves in Rarefield Flow. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 29 and individuals interes...

  14. Toxic shock syndrome

    Science.gov (United States)

    Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

  15. Shock Waves

    CERN Document Server

    Jiang, Z

    2005-01-01

    The International Symposium on Shock Waves (ISSW) is a well established series of conferences held every two years in a different location. A unique feature of the ISSW is the emphasis on bridging the gap between physicists and engineers working in fields as different as gas dynamics, fluid mechanics and materials sciences. The main results presented at these meetings constitute valuable proceedings that offer anyone working in this field an authoritative and comprehensive source of reference.

  16. Shock Prevention

    Science.gov (United States)

    1978-01-01

    The electrician pictured is installing a General Electric Ground Fault Interrupter (GFI), a device which provides protection against electrical shock in the home or in industrial facilities. Shocks due to defective wiring in home appliances or other electrical equipment can cause severe burns, even death. As a result, the National Electrical Code now requires GFIs in all new homes constructed. This particular type of GFI employs a sensing element which derives from technology acquired in space projects by SCI Systems, Inc., Huntsville, Alabama, producer of sensors for GE and other manufacturers of GFI equipment. The sensor is based on the company's experience in developing miniaturized circuitry for space telemetry and other spacecraft electrical systems; this experience enabled SCI to package interruptor circuitry in the extremely limited space available and to produce sensory devices at practicable cost. The tiny sensor measures the strength of the electrical current and detects current differentials that indicate a fault in the functioning of an electrical system. The sensing element then triggers a signal to a disconnect mechanism in the GFI, which cuts off the current in the faulty circuit.

  17. Unified approach to catastrophic events: from the normal state to geological or biological shock in terms of spectral fractal and nonlinear analysis

    Directory of Open Access Journals (Sweden)

    K. A. Eftaxias

    2006-01-01

    Full Text Available An important question in geophysics is whether earthquakes (EQs can be anticipated prior to their occurrence. Pre-seismic electromagnetic (EM emissions provide a promising window through which the dynamics of EQ preparation can be investigated. However, the existence of precursory features in pre-seismic EM emissions is still debatable: in principle, it is difficult to prove associations between events separated in time, such as EQs and their EM precursors. The scope of this paper is the investigation of the pre-seismic EM activity in terms of complexity. A basic reason for our interest in complexity is the striking similarity in behavior close to irreversible phase transitions among systems that are otherwise quite different in nature. Interestingly, theoretical studies (Hopfield, 1994; Herz and Hopfield 1995; Rundle et al., 1995; Corral et al., 1997 suggest that the EQ dynamics at the final stage and neural seizure dynamics should have many similar features and can be analyzed within similar mathematical frameworks. Motivated by this hypothesis, we evaluate the capability of linear and non-linear techniques to extract common features from brain electrical activities and pre-seismic EM emissions predictive of epileptic seizures and EQs respectively. The results suggest that a unified theory may exist for the ways in which firing neurons and opening cracks organize themselves to produce a large crisis, while the preparation of an epileptic shock or a large EQ can be studied in terms of ''Intermittent Criticality''.

  18. Collisionless electrostatic shocks

    DEFF Research Database (Denmark)

    Andersen, H.K.; Andersen, S.A.; Jensen, Vagn Orla

    1970-01-01

    An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth......An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth...

  19. 28th International Symposium on Shock Waves

    CERN Document Server

    2012-01-01

    The University of Manchester hosted the 28th International Symposium on Shock Waves between 17 and 22 July 2011. The International Symposium on Shock Waves first took place in 1957 in Boston and has since become an internationally acclaimed series of meetings for the wider Shock Wave Community. The ISSW28 focused on the following areas: Blast Waves, Chemically Reacting Flows, Dense Gases and Rarefied Flows, Detonation and Combustion, Diagnostics, Facilities, Flow Visualisation, Hypersonic Flow, Ignition, Impact and Compaction, Multiphase Flow, Nozzle Flow, Numerical Methods, Propulsion, Richtmyer-Meshkov, Shockwave Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shockwave Phenomena and Applications, as well as Medical and Biological Applications. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 28 and individuals interested in these fields.

  20. Geometrical shock dynamics for magnetohydrodynamic fast shocks

    KAUST Repository

    Mostert, W.; Pullin, D. I.; Samtaney, Ravi; Wheatley, V.

    2016-01-01

    We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as (Formula presented.), where (Formula presented.) is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock. © 2016 Cambridge University Press

  1. Geometrical shock dynamics for magnetohydrodynamic fast shocks

    KAUST Repository

    Mostert, W.

    2016-12-12

    We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as (Formula presented.), where (Formula presented.) is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock. © 2016 Cambridge University Press

  2. Shock waves and shock tubes; Proceedings of the Fifteenth International Symposium, Berkeley, CA, July 28-August 2, 1985

    International Nuclear Information System (INIS)

    Bershader, D.; Hanson, R.

    1986-01-01

    A detailed survey is presented of shock tube experiments, theoretical developments, and applications being carried out worldwide. The discussions explore shock tube physics and the related chemical, physical and biological science and technology. Extensive attention is devoted to shock wave phenomena in dusty gases and other multiphase and heterogeneous systems, including chemically reactive mixtures. Consideration is given to techniques for measuring, visualizing and theoretically modeling flowfield, shock wave and rarefaction wave characteristics. Numerical modeling is explored in terms of the application of computational fluid dynamics techniques to describing flowfields in shock tubes. Shock interactions and propagation, in both solids, fluids, gases and mixed media are investigated, along with the behavior of shocks in condensed matter. Finally, chemical reactions that are initiated as the result of passage of a shock wave are discussed, together with methods of controlling the evolution of laminar separated flows at concave corners on advanced reentry vehicles

  3. Miniature shock tube for laser driven shocks.

    Science.gov (United States)

    Busquet, Michel; Barroso, Patrice; Melse, Thierry; Bauduin, Daniel

    2010-02-01

    We describe in this paper the design of a miniature shock tube (smaller than 1 cm(3)) that can be placed in a vacuum vessel and allows transverse optical probing and longitudinal backside extreme ultraviolet emission spectroscopy in the 100-500 A range. Typical application is the study of laser launched radiative shocks, in the framework of what is called "laboratory astrophysics."

  4. Are Credit Shocks Supply or Demand Shocks?

    OpenAIRE

    Bijapur, Mohan

    2013-01-01

    This paper provides new insights into the relationship between the supply of credit and the macroeconomy. We present evidence that credit shocks constitute shocks to aggregate supply in that they have a permanent effect on output and cause inflation to rise in the short term. Our results also suggest that the effects on aggregate supply have grown stronger in recent decades.

  5. Shock absorbing structure

    International Nuclear Information System (INIS)

    Kojima, Naoki; Matsushita, Kazuo.

    1992-01-01

    Small pieces of shock absorbers are filled in a space of a shock absorbing vessel which is divided into a plurality of sections by partitioning members. These sections function to prevent excess deformation or replacement of the fillers upon occurrence of falling accident. Since the shock absorbing small pieces in the shock absorbing vessel are filled irregularly, shock absorbing characteristics such as compression strength is not varied depending on the direction, but they exhibit excellent shock absorbing performance. They surely absorb shocks exerted on a transportation vessel upon falling or the like. If existing artificial fillers such as pole rings made of metal or ceramic and cut pieces such as alumium extrusion molding products are used as the shock absorbing pieces, they have excellent fire-proofness and cold resistance since the small pieces are inflammable and do not contain water. (T.M.)

  6. Melting under shock compression

    International Nuclear Information System (INIS)

    Bennett, B.I.

    1980-10-01

    A simple model, using experimentally measured shock and particle velocities, is applied to the Lindemann melting formula to predict the density, temperature, and pressure at which a material will melt when shocked from room temperature and zero pressure initial conditions

  7. Biomass shock pretreatment

    Science.gov (United States)

    Holtzapple, Mark T.; Madison, Maxine Jones; Ramirez, Rocio Sierra; Deimund, Mark A.; Falls, Matthew; Dunkelman, John J.

    2014-07-01

    Methods and apparatus for treating biomass that may include introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber. In some aspects, the method may include pretreating the biomass with a chemical before introducing the biomass to the chamber and/or after transferring shocked biomass from the chamber.

  8. Relativistic Shock Acceleration

    International Nuclear Information System (INIS)

    Duffy, P.; Downes, T.P.; Gallant, Y.A.; Kirk, J.G.

    1999-01-01

    In this paper we briefly review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising some astrophysically interesting cases. We then present an overview of the theory of particle acceleration at such shocks describing the methods used to calculate the spectral indices of energetic particles. Recent results on acceleration at ultra-relativistic shocks are discussed. (author)

  9. Alfven shock trains

    International Nuclear Information System (INIS)

    Malkov, M.A.; Kennel, C.F.; Wu, C.C.; Pellat, R.; Shapiro, V.D.

    1991-01-01

    The Cohen--Kulsrud--Burgers equation (CKB) is used to consider the nonlinear evolution of resistive, quasiparallel Alfven waves subject to a long-wavelength, plane-polarized, monochromatic instability. The instability saturates by nonlinear steepening, which proceeds until the periodic waveform develops an interior scale length comparable to the dissipation length; a fast or an intermediate shock then forms. The result is a periodic train of Alfven shocks of one or the other type. For propagation strictly parallel to the magnetic field, there will be two shocks per instability wavelength. Numerical integration of the time-dependent CKB equation shows that an initial, small-amplitude growing wave asymptotes to a stable, periodic stationary wave whose analytic solution specifies how the type of shock embedded in the shock train, and the amplitude and speed of the shock train, depend on the strength and phase of the instability. Waveforms observed upstream of the Earth's bowshock and cometary shocks resemble those calculated here

  10. System Shock: The Archetype of Operational Shock

    Science.gov (United States)

    2017-05-25

    the battle space. They can also facilitate a much greater understanding of the variables involved in each party’s decision - making process. However...system shock nests within current US Army Unified Land Operations doctrine. In order to test the utility of system shock theory to Gray Zone...23 Neil E. Harrison, “Thinking about the World We Make ” in Chaos Theory in the Social Sciences: Foundations and Applications

  11. Biophoton emission induced by heat shock.

    Directory of Open Access Journals (Sweden)

    Katsuhiro Kobayashi

    Full Text Available Ultraweak biophoton emission originates from the generation of reactive oxygen species (ROS that are produced in mitochondria as by-products of cellular respiration. In healthy cells, the concentration of ROS is minimized by a system of biological antioxidants. However, heat shock changes the equilibrium between oxidative stress and antioxidant activity, that is, a rapid rise in temperature induces biophoton emission from ROS. Although the rate and intensity of biophoton emission was observed to increase in response to elevated temperatures, pretreatment at lower high temperatures inhibited photon emission at higher temperatures. Biophoton measurements are useful for observing and evaluating heat shock.

  12. Hydraulic shock absorbers

    International Nuclear Information System (INIS)

    Thatcher, G.; Davidson, D. F.

    1984-01-01

    A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods

  13. Our Favorite Film Shocks

    DEFF Research Database (Denmark)

    Willerslev, Rane; Suhr, Christian

    2014-01-01

    The modern medium of film has long been hailed for its capacity for producing shocks of an entertaining, thought-provoking, or even politically emancipative nature. But what is a shock, how and when does it occur, how long does it last, and are there particular techniques for producing cinematic...

  14. Climate shocks and conflict

    NARCIS (Netherlands)

    Papaioannou, Kostadis J.

    2016-01-01

    This paper offers a historical micro-level analysis of the impact of climate shocks on the incidence of civil conflict in colonial Nigeria (1912-1945). Primary historical sources on court cases, prisoners and homicides are used to capture conflict. To measure climate shocks we use the deviation

  15. Collisionless shock waves

    International Nuclear Information System (INIS)

    Sagdeev, R.Z.; Kennel, C.F.

    1991-01-01

    Collisionless shocks cannot occur naturally on the earth, because nearly all matter here consists of electrically neutral atoms and molecules. In space, however, high temperatures and ultraviolet radiation from hot stars decompose atoms into their constituent nuclei and electrons, producing a soup of electrically charged particles known as a plasma. Plasma physicists proposed that the collective electrical and magnetic properties of plasmas could produce interactions that take the place of collisions and permit shocks to form. In 1964 the theoretical work found its first experimental confirmation. Norman F. Ness and his colleagues at the Goddard Space Flight Center, using data collected from the iMP-1 spacecraft, detected clear signs that a collisionless shock exists where the solar wind encounters the earth's magnetic field. More recent research has demonstrated that collisionless shocks appear in a dazzling array of astronomical settings. For example, shocks have been found in the solar wind upstream (sunward) of all the planet and comets that have been visited by spacecraft. Violent flares on the sun generate shocks that propagate to the far reaches of the solar system; tremendous galactic outbursts create disruptions in the intergalactic medium that are trillions of times larger. In addition, many astrophysicists think that shocks from supernova explosions in our galaxy accelerate cosmic rays, a class of extraordinarily energetic elementary particles and atomic nuclei that rain down on the earth from all directions

  16. Pediatric Toxic Shock Syndrome

    Directory of Open Access Journals (Sweden)

    Jennifer Yee

    2017-09-01

    Full Text Available Audience: This scenario was developed to educate emergency medicine residents on the diagnosis and management of a pediatric patient with toxic shock syndrome. The case is also appropriate for teaching of medical students and advanced practice providers, as well as a review of the principles of crisis resource management, teamwork, and communication. Introduction: Toxic shock syndrome is a low-frequency, high-acuity scenario requiring timely identification and aggressive management. If patients suffering from this condition are managed incorrectly, they may progress into multi-organ dysfunction and potentially death. Toxic shock syndrome has been associated with Streptococcus and Staphylococcus aureus (Staph. Approximately half of Staph cases are associated with menstruation, which was first described in the 1970s-1980s and was associated with the use of absorbent tampons.1 Group A Streptococcus may cause complications such as necrotizing fasciitis and gangrenous myositis.2 Pediatric patients may present critically ill from toxic shock syndrome. Providers need to perform a thorough history and physical exam to discern the source of infection. Management requires aggressive care with antibiotics and IV fluids. Objectives: By the end of this simulation session, the learner will be able to: 1 Recognize toxic shock syndrome. 2 Review the importance of a thorough physical exam. 3 Discuss management of toxic shock syndrome, including supportive care and the difference in antibiotic choices for streptococcal and staphylococcal toxic shock syndrome. 4 Appropriately disposition a patient suffering from toxic shock syndrome. 5 Communicate effectively with team members and nursing staff during a resuscitation of a critically ill patient. Method: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on toxic shock syndrome.

  17. Shocks near Jamming

    Science.gov (United States)

    Gómez, Leopoldo R.; Turner, Ari M.; van Hecke, Martin; Vitelli, Vincenzo

    2012-02-01

    Nonlinear sound is an extreme phenomenon typically observed in solids after violent explosions. But granular media are different. Right when they jam, these fragile and disordered solids exhibit a vanishing rigidity and sound speed, so that even tiny mechanical perturbations form supersonic shocks. Here, we perform simulations in which two-dimensional jammed granular packings are dynamically compressed and demonstrate that the elementary excitations are strongly nonlinear shocks, rather than ordinary phonons. We capture the full dependence of the shock speed on pressure and impact intensity by a surprisingly simple analytical model.

  18. Mechanical shock absorber

    International Nuclear Information System (INIS)

    Vrillon, Bernard.

    1973-01-01

    The mechanical shock absorber described is made of a constant thickness plate pierced with circular holes regularly distributed in such a manner that for all the directions along which the strain is applied during the shock, the same section of the substance forming the plate is achieved. The shock absorber is made in a metal standing up to extensive deformation before breaking, selected from a group comprising mild steels and austenitic stainless steels. This apparatus is used for handling pots of fast neutron reactor fuel elements [fr

  19. Shock formation of HCO+

    International Nuclear Information System (INIS)

    Elitzur, M.

    1983-01-01

    It is shown that shocks propagating in dense molecular regions will lead to a decrease in HCO + relative abundance, in agreement with previous results by Iglesias and Silk. The shock enhancement of HCO + detected in the supernova remnant IC 443 by Dickenson et al. is due to enhanced ionization in the shocked material. This is the result of the material penetrating the remnant cavity where it becomes exposed to the trapped cosmic rays. A similar enhancement appears to have been detected by Wootten in W28 and is explained by the same model

  20. Shock Isolation Elements Testing for High Input Loadings. Volume II. Foam Shock Isolation Elements.

    Science.gov (United States)

    SHOCK ABSORBERS ), (*GUIDED MISSILE SILOS, SHOCK ABSORBERS ), (*EXPANDED PLASTICS, (*SHOCK(MECHANICS), REDUCTION), TEST METHODS, SHOCK WAVES, STRAIN(MECHANICS), LOADS(FORCES), MATHEMATICAL MODELS, NUCLEAR EXPLOSIONS, HARDENING.

  1. Endogenous leukotriene formation during anaphylactic shock

    International Nuclear Information System (INIS)

    Keppler, A.; Oerning, L.; Bernstroem, K.; Hammarstroem, S.

    1987-01-01

    Leukotriene (LT)C 4 is a biologically active substance, presumed to play major roles as a mediator of allergic and anaphylactic reactions. It is formed e.g. by basophilic and eosinophilic leukocytes, monocytes, macrophages, and mast cells. In cells having IgE receptors, bridging of these by divalent anti-IgE-receptor antibodies or by interaction between receptor-bound IgE and anti-IgE will induce LTC 4 formation. Leukotriene formation has also been demonstrated in other in vitro models of immediate hypersensivity. The biological actions of LTC 4 , comprise induction of airway obstruction, constriction of coronary arteries, hypotension, and plasma extravasation. Leukotriene formation in vivo may mediate anaphylactic shock symptoms and cause the death of an animal. In order to prove the presumed mediator role of this substance in anaphylactic reactions, it is necessary to demonstrate its endogenous formation during shock. Studies on the metabolism of LTC 4 have revealed rapid catabolism by various transformations of the peptide substituent. Recently, three metabolites were demonstrated to be excreted as end-products in man (LTE 4 ,) and the rat (N-acetyl LTE 4 and N-acetyl 11-trans LTE 4 ). By monitoring biliary N-acetyl LTE 4 levels, endogenous leukotriene formation in the rat was demonstrated in vivo after tissue trauma and endotoxin shock. We now wish to report evidence for endogenous leukotriene C 4 production during anaphylactic shock in guinea pigs. 37 refs. (author)

  2. Counseling For Future Shock

    Science.gov (United States)

    Morgan, Lewis B.

    1974-01-01

    In this article the author looks at some of the searing prophecies made by Alvin Toffler in his book Future Shock and relates them to the world of the professional counselor and the clientele the counselor attempts to serve. (Author)

  3. Life shocks and homelessness.

    Science.gov (United States)

    Curtis, Marah A; Corman, Hope; Noonan, Kelly; Reichman, Nancy E

    2013-12-01

    We exploited an exogenous health shock-namely, the birth of a child with a severe health condition-to investigate the effect of a life shock on homelessness in large cities in the United States as well as the interactive effects of the shock with housing market characteristics. We considered a traditional measure of homelessness, two measures of housing instability thought to be precursors to homelessness, and a combined measure that approximates the broadened conceptualization of homelessness under the 2009 Homeless Emergency Assistance and Rapid Transition to Housing Act (2010). We found that the shock substantially increases the likelihood of family homelessness, particularly in cities with high housing costs. The findings are consistent with the economic theory of homelessness, which posits that homelessness results from a conjunction of adverse circumstances in which housing markets and individual characteristics collide.

  4. Unlimited Relativistic Shock Surfing Acceleration

    International Nuclear Information System (INIS)

    Ucer, D.; Shapiro, V. D.

    2001-01-01

    Nonrelativistic shock surfing acceleration at quasiperpendicular shocks is usually considered to be a preacceleration mechanism for slow pickup ions to initiate diffusive shock acceleration. In shock surfing, the particle accelerates along the shock front under the action of the convective electric field of the plasma flow. However, the particle also gains kinetic energy normal to the shock and eventually escapes downstream. We consider the case when ions are accelerated to relativistic velocities. In this case, the ions are likely to be trapped for infinitely long times, because the energy of bounce oscillations tends to decrease during acceleration. This suggests the possibility of unlimited acceleration by shock surfing

  5. Technology shocks matter

    OpenAIRE

    Jonas D. M. Fisher

    2002-01-01

    This paper uses the neoclassical growth model to identify the effects of technological change on the US business cycle. In the model there are two sources of technological change: neutral, which effects the production of all goods homogeneously, and investment-specific. Investment-specific shocks are the unique source of the secular trend in the real price of investment goods, while shocks to both kinds of technology are the only factors which affect labor productivity in the long run. Consis...

  6. The Heliospheric Termination Shock

    Science.gov (United States)

    Jokipii, J. R.

    2013-06-01

    The heliospheric termination shock is a vast, spheroidal shock wave marking the transition from the supersonic solar wind to the slower flow in the heliosheath, in response to the pressure of the interstellar medium. It is one of the most-important boundaries in the outer heliosphere. It affects energetic particles strongly and for this reason is a significant factor in the effects of the Sun on Galactic cosmic rays. This paper summarizes the general properties and overall large-scale structure and motions of the termination shock. Observations over the past several years, both in situ and remote, have dramatically revised our understanding of the shock. The consensus now is that the shock is quite blunt, is with the front, blunt side canted at an angle to the flow direction of the local interstellar plasma relative to the Sun, and is dynamical and turbulent. Much of this new understanding has come from remote observations of energetic charged particles interacting with the shock, radio waves and radiation backscattered from interstellar neutral atoms. The observations and the implications are discussed.

  7. Shocks in fragile matter

    Science.gov (United States)

    Vitelli, Vincenzo

    2012-02-01

    Non-linear sound is an extreme phenomenon typically observed in solids after violent explosions. But granular media are different. Right when they unjam, these fragile and disordered solids exhibit vanishing elastic moduli and sound speed, so that even tiny mechanical perturbations form supersonic shocks. Here, we perform simulations in which two-dimensional jammed granular packings are continuously compressed, and demonstrate that the resulting excitations are strongly nonlinear shocks, rather than linear waves. We capture the full dependence of the shock speed on pressure and compression speed by a surprisingly simple analytical model. We also treat shear shocks within a simplified viscoelastic model of nearly-isostatic random networks comprised of harmonic springs. In this case, anharmonicity does not originate locally from nonlinear interactions between particles, as in granular media; instead, it emerges from the global architecture of the network. As a result, the diverging width of the shear shocks bears a nonlinear signature of the diverging isostatic length associated with the loss of rigidity in these floppy networks.

  8. Physics of Collisionless Shocks Space Plasma Shock Waves

    CERN Document Server

    Balogh, André

    2013-01-01

    The present book provides a contemporary systematic treatment of shock waves in high-temperature collisionless plasmas as are encountered in near Earth space and in Astrophysics. It consists of two parts. Part I develops the complete theory of shocks in dilute hot plasmas under the assumption of absence of collisions among the charged particles when the interaction is mediated solely by the self-consistent electromagnetic fields. Such shocks are naturally magnetised implying that the magnetic field plays an important role in their evolution and dynamics. This part treats both subcritical shocks, which dissipate flow energy by generating anomalous resistance or viscosity, and supercritical shocks. The main emphasis is, however, on super-critical shocks where the anomalous dissipation is insufficient to retard the upstream flow. These shocks, depending on the direction of the upstream magnetic field, are distinguished as quasi-perpendicular and quasi-parallel shocks which exhibit different behaviours, reflecti...

  9. Life Shocks and Homelessness

    Science.gov (United States)

    Corman, Hope; Noonan, Kelly; Reichman, Nancy E.

    2014-01-01

    We exploited an exogenous health shock—namely, the birth of a child with a severe health condition—to investigate the effect of a life shock on homelessness in large cities in the United States as well as the interactive effects of the shock with housing market characteristics. We considered a traditional measure of homelessness, two measures of housing instability thought to be precursors to homelessness, and a combined measure that approximates the broadened conceptualization of homelessness under the 2009 Homeless Emergency Assistance and Rapid Transition to Housing Act (2010). We found that the shock substantially increases the likelihood of family homelessness, particularly in cities with high housing costs. The findings are consistent with the economic theory of homelessness, which posits that homelessness results from a conjunction of adverse circumstances in which housing markets and individual characteristics collide. PMID:23868747

  10. Health Shocks and Retirement:

    DEFF Research Database (Denmark)

    Datta Gupta, Nabanita; Larsen, Mona

    We investigate the effect of an acute health shock on retirement among elderly male workers in Denmark, 1991-1999, and in particular whether various welfare state programs and institutions impinge on the retirement effect. The results show that an acute health event increases the retirement chances...... significant. For the most part, the retirement effect following a health shock seems to be immune to the availability of a multitude of government programs for older workers in Denmark....... benefits in Denmark nor by the promotion of corporate social responsibility initiatives since the mid-1990s. In the late 1990s, however, the retirement rate following a health shock is reduced to 3% with the introduction of the subsidized employment program (fleksjob) but this effect is not strongly...

  11. RNA-Seq-based analysis of cold shock response in Thermoanaerobacter tengcongensis, a bacterium harboring a single cold shock protein encoding gene.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available BACKGROUND: Although cold shock responses and the roles of cold shock proteins in microorganisms containing multiple cold shock protein genes have been well characterized, related studies on bacteria possessing a single cold shock protein gene have not been reported. Thermoanaerobacter tengcongensis MB4, a thermophile harboring only one known cold shock protein gene (TtescpC, can survive from 50° to 80 °C, but has poor natural competence under cold shock at 50 °C. We therefore examined cold shock responses and their effect on natural competence in this bacterium. RESULTS: The transcriptomes of T. tengcongensis before and after cold shock were analyzed by RNA-seq and over 1200 differentially expressed genes were successfully identified. These genes were involved in a wide range of biological processes, including modulation of DNA replication, recombination, and repair; energy metabolism; production of cold shock protein; synthesis of branched amino acids and branched-chain fatty acids; and sporulation. RNA-seq analysis also suggested that T. tengcongensis initiates cell wall and membrane remodeling processes, flagellar assembly, and sporulation in response to low temperature. Expression profiles of TtecspC and failed attempts to produce a TtecspC knockout strain confirmed the essential role of TteCspC in the cold shock response, and also suggested a role of this protein in survival at optimum growth temperature. Repression of genes encoding ComEA and ComEC and low energy metabolism levels in cold-shocked cells are the likely basis of poor natural competence at low temperature. CONCLUSION: Our study demonstrated changes in global gene expression under cold shock and identified several candidate genes related to cold shock in T. tengcongensis. At the same time, the relationship between cold shock response and poor natural competence at low temperature was preliminarily elucidated. These findings provide a foundation for future studies on genetic

  12. The Shock Routine

    DEFF Research Database (Denmark)

    van Hooren, Franca; Kaasch, Alexandra; Starke, Peter

    2014-01-01

    in Australia, Belgium, the Netherlands and Sweden over the course of four global economic shocks, we ask whether the notion of critical junctures is useful in understanding the nature of change triggered by crisis. The main empirical finding is that fundamental change in the aftermath of an exogenous shock...... is the exception rather than the rule. Instead, incremental ‘crisis routines’ based on existing policy instruments are overwhelmingly used to deal with economic hardship. We discuss these findings in the light of the psychological ‘threat-rigidity’ effect and reflect on their consequences for theories...

  13. Shock absorber in Ignalina NPP

    International Nuclear Information System (INIS)

    Bulavas, A.; Muralis, J.

    1996-09-01

    Theoretical calculation and experimental analysis of models of shock absorber in Ignalina NPP is presented. The results obtained from the investigation with model of shock absorber coincide with the theoretical calculation. (author). 2 figs., 3 refs

  14. Shock Response of Boron Carbide

    National Research Council Canada - National Science Library

    Dandekar, D. P. (Dattatraya Purushottam)

    2001-01-01

    .... The present work was undertaken to determine tensile/spall strength of boron carbide under plane shock wave loading and to analyze all available shock compression data on boron carbide materials...

  15. Fascinating World of Shock Waves

    Indian Academy of Sciences (India)

    Srimath

    travelling at supersonic speeds (more than the sound speed at ... actual earth- quake, travel at supersonic speeds. .... The time scale of the shock wave is also important ..... real lithotripsy where a shock wave is used shatter the kidney stones!

  16. Developing a New Definition and Assessing New Clinical Criteria for Septic Shock For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)

    NARCIS (Netherlands)

    Shankar-Hari, Manu; Phillips, Gary S.; Levy, Mitchell L.; Seymour, Christopher W.; Liu, Vincent X.; Deutschman, Clifford S.; Angus, Derek C.; Rubenfeld, Gordon D.; Singer, Mervyn; Angus, Derek; Annane, Djilalli; Bauer, Michael; Bellomo, Rinaldo; Bernard, Gordon; Chiche, Jean-Daniel; Coopersmith, Craig; Deutschman, Cliff; Hotchkiss, Richard; Levy, Mitchell; Marshall, John; Martin, Greg; Opal, Steve; Rubenfeld, Gordon; Seymour, Christopher; van der Poll, Tom; Vincent, Jean-Louis

    2016-01-01

    IMPORTANCE Septic shock currently refers to a state of acute circulatory failure associated with infection. Emerging biological insights and reported variation in epidemiology challenge the validity of this definition. OBJECTIVE To develop a new definition and clinical criteria for identifying

  17. INTERFERENCE OF UNIDIRECTIONAL SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-05-01

    Full Text Available Subject of study.We consider interference of unidirectional shock waves or, as they are called, catching up shock waves. The scope of work is to give a classification of the shock-wave structures that arise in this type of interaction of shock waves, and the area of their existence. Intersection of unidirectional shock waves results in arising of a shock-wave structure at the intersection point, which contains the main shock wave, tangential discontinuity and one more reflected gas-dynamic discontinuity of unknown beforehand type. The problem of determining the type of reflected discontinuity is the main problem that one has to solve in the study of catching shock waves interference. Main results.The paper presents the pictures of shock-wave structures arising at the interaction of catching up shock waves. The areas with a regular and irregular unidirectional interaction of shocks are described. Characteristic shock-wave structures are of greatest interest, where reflected gas-dynamic discontinuity degenerates into discontinuous characteristics. Such structures have a number of extreme properties. We have found the areas of existence for such shock-wave structures. There are also areas in which the steady-state solution is not available. The latter has determined revival of interest for the theoretical study of the problem, because the facts of sudden shock-wave structure destruction inside the air intake of supersonic aircrafts at high Mach numbers have been discovered. Practical significance.The theory of interference for unidirectional shock waves and design procedure are usable in the design of supersonic air intakes. It is also relevant for application possibility investigation of catching up oblique shock waves to create overcompressed detonation in perspective detonation air-jet and rocket engines.

  18. Shock tube Multiphase Experiments

    Science.gov (United States)

    Middlebrooks, John; Allen, Roy; Paudel, Manoj; Young, Calvin; Musick, Ben; McFarland, Jacob

    2017-11-01

    Shock driven multiphase instabilities (SDMI) are unique physical phenomena that have far-reaching practical applications in engineering and science. The instability is present in high energy explosions, scramjet combustors, and supernovae events. The SDMI arises when a multiphase interface is impulsively accelerated by the passage of a shockwave. It is similar in development to the Richtmyer-Meshkov (RM) instability however, particle-to-gas coupling is the driving mechanism of the SDMI. As particle effects such as lag and phase change become more prominent, the SDMI's development begins to significantly deviate from the RM instability. We have developed an experiment for studying the SDMI in our shock tube facility. In our experiments, a multiphase interface is created using a laminar jet and flowed into the shock tube where it is accelerated by the passage of a planar shockwave. The interface development is captured using CCD cameras synchronized with planar laser illumination. This talk will give an overview of new experiments conducted to examine the development of a shocked cylindrical multiphase interface. The effects of Atwood number, particle size, and a second acceleration (reshock) of the interface will be discussed.

  19. Teleconnected food supply shocks

    Science.gov (United States)

    Bren d'Amour, Christopher; Wenz, Leonie; Kalkuhl, Matthias; Steckel, Jan Christoph; Creutzig, Felix

    2016-03-01

    The 2008-2010 food crisis might have been a harbinger of fundamental climate-induced food crises with geopolitical implications. Heat-wave-induced yield losses in Russia and resulting export restrictions led to increases in market prices for wheat across the Middle East, likely contributing to the Arab Spring. With ongoing climate change, temperatures and temperature variability will rise, leading to higher uncertainty in yields for major nutritional crops. Here we investigate which countries are most vulnerable to teleconnected supply-shocks, i.e. where diets strongly rely on the import of wheat, maize, or rice, and where a large share of the population is living in poverty. We find that the Middle East is most sensitive to teleconnected supply shocks in wheat, Central America to supply shocks in maize, and Western Africa to supply shocks in rice. Weighing with poverty levels, Sub-Saharan Africa is most affected. Altogether, a simultaneous 10% reduction in exports of wheat, rice, and maize would reduce caloric intake of 55 million people living in poverty by about 5%. Export bans in major producing regions would put up to 200 million people below the poverty line at risk, 90% of which live in Sub-Saharan Africa. Our results suggest that a region-specific combination of national increases in agricultural productivity and diversification of trade partners and diets can effectively decrease future food security risks.

  20. STEREO interplanetary shocks and foreshocks

    International Nuclear Information System (INIS)

    Blanco-Cano, X.; Kajdič, P.; Aguilar-Rodríguez, E.; Russell, C. T.; Jian, L. K.; Luhmann, J. G.

    2013-01-01

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and θ Bn ∼20-86°. We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr ≤0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at ∼1 AU and have been producing suprathermal particles for a shorter time.

  1. STEREO interplanetary shocks and foreshocks

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Cano, X. [Instituto de Geofisica, UNAM, CU, Coyoacan 04510 DF (Mexico); Kajdic, P. [IRAP-University of Toulouse, CNRS, Toulouse (France); Aguilar-Rodriguez, E. [Instituto de Geofisica, UNAM, Morelia (Mexico); Russell, C. T. [ESS and IGPP, University of California, Los Angeles, 603 Charles Young Drive, Los Angeles, CA 90095 (United States); Jian, L. K. [NASA Goddard Space Flight Center, Greenbelt, MD and University of Maryland, College Park, MD (United States); Luhmann, J. G. [SSL, University of California Berkeley (United States)

    2013-06-13

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and {theta}{sub Bn}{approx}20-86 Degree-Sign . We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr {<=}0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at {approx}1 AU and have been producing suprathermal particles for a shorter time.

  2. Shock Dynamics in Stellar Outbursts. I. Shock Formation

    Energy Technology Data Exchange (ETDEWEB)

    Ro, Stephen; Matzner, Christopher D., E-mail: ro@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

    2017-05-20

    Wave-driven outflows and non-disruptive explosions have been implicated in pre-supernova outbursts, supernova impostors, luminous blue variable eruptions, and some narrow-line and superluminous supernovae. To model these events, we investigate the dynamics of stars set in motion by strong acoustic pulses and wave trains, focusing on nonlinear wave propagation, shock formation, and an early phase of the development of a weak shock. We identify the shock formation radius, showing that a heuristic estimate based on crossing characteristics matches an exact expansion around the wave front and verifying both with numerical experiments. Our general analytical condition for shock formation applies to one-dimensional motions within any static environment, including both eruptions and implosions. We also consider the early phase of shock energy dissipation. We find that waves of super-Eddington acoustic luminosity always create shocks, rather than damping by radiative diffusion. Therefore, shock formation is integral to super-Eddington outbursts.

  3. Grain destruction in interstellar shocks

    International Nuclear Information System (INIS)

    Seab, C.G.; Shull, J.M.

    1984-01-01

    One of the principal methods for removing grains from the Interstellar Medium is to destroy them in shock waves. Previous theoretical studies of shock destruction have generally assumed only a single size and type of grain; most do not account for the effect of the grain destruction on the structure of the shock. Earlier calculations have been improved in three ways: first, by using a ''complete'' grain model including a distribution of sizes and types of grains; second, by using a self-consistent shock structure that incorporates the changing elemental depletions as the grains are destroyed; and third, by calculating the shock-processed ultraviolet extinction curves for comparison with observations. (author)

  4. Bubble Dynamics and Shock Waves

    CERN Document Server

    2013-01-01

    This volume of the Shock Wave Science and Technology Reference Library is concerned with the interplay between bubble dynamics and shock waves. It is divided into four parts containing twelve chapters written by eminent scientists. Topics discussed include shock wave emission by laser generated bubbles (W Lauterborn, A Vogel), pulsating bubbles near boundaries (DM Leppinen, QX Wang, JR Blake), interaction of shock waves with bubble clouds (CD Ohl, SW Ohl), shock propagation in polydispersed bubbly liquids by model equations (K Ando, T Colonius, CE Brennen. T Yano, T Kanagawa,  M Watanabe, S Fujikawa) and by DNS (G Tryggvason, S Dabiri), shocks in cavitating flows (NA Adams, SJ Schmidt, CF Delale, GH Schnerr, S Pasinlioglu) together with applications involving encapsulated bubble dynamics in imaging (AA Doinikov, A Novell, JM Escoffre, A Bouakaz),  shock wave lithotripsy (P Zhong), sterilization of ships’ ballast water (A Abe, H Mimura) and bubbly flow model of volcano eruptions ((VK Kedrinskii, K Takayama...

  5. Adjustable Shock Absorbers

    OpenAIRE

    Adamiec, Radek

    2012-01-01

    Bakalářská práce obsahuje přehled používaných tlumičů osobních automobilů, závodních automobilů a motocyklů. Jsou zde popsány systémy t lumením, konstrukce tlumičů a vidlic používaných u motocyklů. Dále je zde přehled prvků používaných u podvozků automobilů. This bachelor´s thesis contains the survey of the shock absorbers of passenger cars, racing cars and motorcycles. Are described damping systems, the design used shock absorbers and forks for motorcycles. Then there is the list of the e...

  6. Radiative relativistic shock adiabate

    International Nuclear Information System (INIS)

    Tsintsadze, L.N.; Nishikawa, K.

    1997-01-01

    The influences of thermal radiation on the state equation of shock waves, derived in the previous paper [L. N. Tsintsadze, Phys. Plasmas 2, 4462 (1995)], are studied and a series of relations of thermodynamic quantities that hold for shock waves are derived. It is shown that the presence of radiation can strongly change the compressibility of the plasma. It is well known that for polytropic gases the compressibility cannot change more than four times the initial value in the case of nonrelativistic temperatures. The numerical calculations show that there are no such restrictions, when the radiation energy exceeds the kinetic energy of the plasma. The ultrarelativistic temperature range is also covered in our numerical calculations. Also studied are the influences of the radiation on the PT and the TV diagrams. A significant modification due to radiation is found in every case studied. copyright 1997 American Institute of Physics

  7. POSTURAL SHOCK IN PREGNANCY

    Science.gov (United States)

    Wilkening, Ralph L.; Knauer, John; Larson, Roger K.

    1955-01-01

    Signs and symptoms of shock may be produced in some patients in late pregnancy by putting them in the dorsal recumbent posture. Change from this position will relieve the condition. The features of the supine hypotensive syndrome can be duplicated by applying pressure to the abdomen with the patient in a lateral position. The postural variations of venous pressure, blood pressure, and pulse appear to be due to obstruction of venous return from the lower portion of the body caused by the large uterus of late pregnancy compressing the vena cava. When shock is observed in a woman in late pregnancy, she should be turned to a lateral position before more active measures of treatment are begun. ImagesFigure 1. PMID:14351983

  8. Bow shock data analysis

    Science.gov (United States)

    Zipf, Edward C.; Erdman, Peeter W.

    1994-08-01

    The University of Pittsburgh Space Physics Group in collaboration with the Army Research Office (ARO) modeling team has completed a systematic organization of the shock and plume spectral data and the electron temperature and density measurements obtained during the BowShock I and II rocket flights which have been submitted to the AEDC Data Center, has verified the presence of CO Cameron band emission during the Antares engine burn and for an extended period of time in the post-burn plume, and have adapted 3-D radiation entrapment codes developed by the University of Pittsburgh to study aurora and other atmospheric phenomena that involve significant spatial effects to investigate the vacuum ultraviolet (VUV) and extreme ultraviolet (EUV) envelope surrounding the re-entry that create an extensive plasma cloud by photoionization.

  9. Shock Isolation Elements Testing for High Input Loadings. Volume III. Mechanical Shock Isolation Elements.

    Science.gov (United States)

    SHOCK ABSORBERS ), (*GUIDED MISSILE SILOS, SHOCK ABSORBERS ), (*SPRINGS, (*SHOCK(MECHANICS), REDUCTION), TORSION BARS, ELASTOMERS, DAMPING, EQUATIONS OF MOTION, MODEL TESTS, TEST METHODS, NUCLEAR EXPLOSIONS, HARDENING.

  10. Shock resistance testing

    International Nuclear Information System (INIS)

    Pouard, M.

    1984-03-01

    In the framework of mechanical tests and to answer the different requests for tests, the T.C.R (Transport Conditionnement et Retraitement) laboratory got test facilities. These installations allow to carry out tests of resistance to shocks, mainly at the safety level of components of nuclear power plants, mockups of transport casks for fuel elements and transport containers for radioactive materials. They include a tower and a catapult. This paper give a decription of the facilities and explain their operation way [fr

  11. On Modeling Risk Shocks

    OpenAIRE

    Dorofeenko, Victor; Lee, Gabriel; Salyer, Kevin; Strobel, Johannes

    2016-01-01

    Within the context of a financial accelerator model, we model time-varying uncertainty (i.e. risk shocks) through the use of a mixture Normal model with time variation in the weights applied to the underlying distributions characterizing entrepreneur productivity. Specifically, we model capital producers (i.e. the entrepreneurs) as either low-risk (relatively small second moment for productivity) and high-risk (relatively large second moment for productivity) and the fraction of both types is...

  12. The Shock Doctrine

    OpenAIRE

    Dionysios K. Solomos; Dimitrios N. Koumparoulis

    2011-01-01

    Naomi Klein attempts to redefine the economic history discovering the historical continuities and to reveal the neoliberal theory which functions via the utilization of specific “tools”. The state of shock is the key for the opponents of Chicago School and Milton Friedman in order for them to establish neoliberal policies and to promote the deregulated capitalism which includes less welfare state, less public sector, less regulation, weakened labor unions, privatizations and laissez-faire. Th...

  13. Characterization of shocked beryllium

    Directory of Open Access Journals (Sweden)

    Papin P.A.

    2012-08-01

    Full Text Available While numerous studies have investigated the low-strain-rate constitutive response of beryllium, the combined influence of high strain rate and temperature on the mechanical behavior and microstructure of beryllium has received limited attention over the last 40 years. In the current work, high strain rate tests were conducted using both explosive drive and a gas gun to accelerate the material. Prior studies have focused on tensile loading behavior, or limited conditions of dynamic strain rate and/or temperature. Two constitutive strength (plasticity models, the Preston-Tonks-Wallace (PTW and Mechanical Threshold Stress (MTS models, were calibrated using common quasi-static and Hopkinson bar data. However, simulations with the two models give noticeably different results when compared with the measured experimental wave profiles. The experimental results indicate that, even if fractured by the initial shock loading, the Be remains sufficiently intact to support a shear stress following partial release and subsequent shock re-loading. Additional “arrested” drive shots were designed and tested to minimize the reflected tensile pulse in the sample. These tests were done to both validate the model and to put large shock induced compressive loads into the beryllium sample.

  14. Selfsimilar time dependent shock structures

    International Nuclear Information System (INIS)

    Beck, R.; Drury, L.O.

    1985-01-01

    Diffusive shock acceleration as an astrophysical mechanism for accelerating charged particles has the advantage of being highly efficient. This means however that the theory is of necessity nonlinear; the reaction of the accelerated particles on the shock structure and the acceleration process must be self-consistently included in any attempt to develop a complete theory of diffusive shock acceleration. Considerable effort has been invested in attempting, at least partially, to do this and it has become clear that in general either the maximum particle energy must be restricted by introducing additional loss processes into the problem or the acceleration must be treated as a time dependent problem (Drury, 1984). It is concluded that stationary modified shock structures can only exist for strong shocks if additional loss processes limit the maximum energy a particle can attain. This is certainly possible and if it occurs the energy loss from the shock will lead to much greater shock compressions. It is however equally possible that no such processes exist and we must then ask what sort of nonstationary shock structure develops. The same argument which excludes stationary structures also rules out periodic solutions and indeed any solution where the width of the shock remains bounded. It follows that the width of the shock must increase secularly with time and it is natural to examine the possibility of selfsimilar time dependent solutions

  15. Selfsimilar time dependent shock structures

    Science.gov (United States)

    Beck, R.; Drury, L. O.

    1985-01-01

    Diffusive shock acceleration as an astrophysical mechanism for accelerating charged particles has the advantage of being highly efficient. This means however that the theory is of necessity nonlinear; the reaction of the accelerated particles on the shock structure and the acceleration process must be self-consistently included in any attempt to develop a complete theory of diffusive shock acceleration. Considerable effort has been invested in attempting, at least partially, to do this and it has become clear that in general either the maximum particle energy must be restricted by introducing additional loss processes into the problem or the acceleration must be treated as a time dependent problem (Drury, 1984). It is concluded that stationary modified shock structures can only exist for strong shocks if additional loss processes limit the maximum energy a particle can attain. This is certainly possible and if it occurs the energy loss from the shock will lead to much greater shock compressions. It is however equally possible that no such processes exist and we must then ask what sort of nonstationary shock structure develops. The ame argument which excludes stationary structures also rules out periodic solutions and indeed any solution where the width of the shock remains bounded. It follows that the width of the shock must increase secularly with time and it is natural to examine the possibility of selfsimilar time dependent solutions.

  16. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)

    NARCIS (Netherlands)

    Singer, Mervyn; Deutschman, Clifford S.; Seymour, Christopher Warren; Shankar-Hari, Manu; Annane, Djillali; Bauer, Michael; Bellomo, Rinaldo; Bernard, Gordon R.; Chiche, Jean-Daniel; Coopersmith, Craig M.; Hotchkiss, Richard S.; Levy, Mitchell M.; Marshall, John C.; Martin, Greg S.; Opal, Steven M.; Rubenfeld, Gordon D.; van der Poll, Tom; Vincent, Jean-Louis; Angus, Derek C.

    2016-01-01

    IMPORTANCE Definitions of sepsis and septic shock were last revised in 2001. Considerable advances have since been made into the pathobiology (changes in organ function, morphology, cell biology, biochemistry, immunology, and circulation), management, and epidemiology of sepsis, suggesting the need

  17. Risk shocks and housing markets

    OpenAIRE

    Dorofeenko, Viktor; Lee, Gabriel S.; Salyer, Kevin D.

    2010-01-01

    Abstract: This paper analyzes the role of uncertainty in a multi-sector housing model with financial frictions. We include time varying uncertainty (i.e. risk shocks) in the technology shocks that affect housing production. The analysis demonstratesthat risk shocks to the housing production sector are a quantitatively important impulse mechanism for the business cycle. Also, we demonstrate that bankruptcy costs act as an endogenous markup factor in housing prices; as a consequence, the volati...

  18. Heat shock protein 90 in neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Rodina Anna

    2010-06-01

    Full Text Available Abstract Hsp90 is a molecular chaperone with important roles in regulating pathogenic transformation. In addition to its well-characterized functions in malignancy, recent evidence from several laboratories suggests a role for Hsp90 in maintaining the functional stability of neuronal proteins of aberrant capacity, whether mutated or over-activated, allowing and sustaining the accumulation of toxic aggregates. In addition, Hsp90 regulates the activity of the transcription factor heat shock factor-1 (HSF-1, the master regulator of the heat shock response, mechanism that cells use for protection when exposed to conditions of stress. These biological functions therefore propose Hsp90 inhibition as a dual therapeutic modality in neurodegenerative diseases. First, by suppressing aberrant neuronal activity, Hsp90 inhibitors may ameliorate protein aggregation and its associated toxicity. Second, by activation of HSF-1 and the subsequent induction of heat shock proteins, such as Hsp70, Hsp90 inhibitors may redirect neuronal aggregate formation, and protect against protein toxicity. This mini-review will summarize our current knowledge on Hsp90 in neurodegeneration and will focus on the potential beneficial application of Hsp90 inhibitors in neurodegenerative diseases.

  19. Health shocks and risk aversion.

    Science.gov (United States)

    Decker, Simon; Schmitz, Hendrik

    2016-12-01

    We empirically assess whether a health shock influences individual risk aversion. We use grip strength data to obtain an objective health shock indicator. In order to account for the non-random nature of our data regression-adjusted matching is employed. Risk preferences are traditionally assumed to be constant. However, we find that a health shock increases individual risk aversion. The finding is robust to a series of sensitivity analyses and persists for at least four years after the shock. Income changes do not seem to be the driving mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Shock in the emergency department

    DEFF Research Database (Denmark)

    Holler, Jon Gitz; Henriksen, Daniel Pilsgaard; Mikkelsen, Søren

    2016-01-01

    BACKGROUND: The knowledge of the frequency and associated mortality of shock in the emergency department (ED) is limited. The aim of this study was to describe the incidence, all-cause mortality and factors associated with death among patients suffering shock in the ED. METHODS: Population...... failures. Outcomes were annual incidence per 100,000 person-years at risk (pyar), all-cause mortality at 0-7, and 8-90 days and risk factors associated with death. RESULTS: We identified 1646 of 438,191 (0.4 %) ED patients with shock at arrival. Incidence of shock increased from 53.8 to 80.6 cases per 100...

  1. Shock compression of diamond crystal

    OpenAIRE

    Kondo, Ken-ichi; Ahrens, Thomas J.

    1983-01-01

    Two shock wave experiments employing inclined mirrors have been carried out to determine the Hugoniot elastic limit (HEL), final shock state at 191 and 217 GPa, and the post-shock state of diamond crystal, which is shock-compressed along the intermediate direction between the and crystallographic axes. The HEL wave has a velocity of 19.9 ± 0.3 mm/µsec and an amplitude of 63 ± 28 GPa. An alternate interpretation of the inclined wedge mirror streak record suggests a ramp precursor wave and th...

  2. A Shocking Solar Nebula?

    OpenAIRE

    Liffman, Kurt

    2009-01-01

    It has been suggested that shock waves in the solar nebula formed the high temperature materials observed in meteorites and comets. It is shown that the temperatures at the inner rim of the solar nebula could have been high enough over a sufficient length of time to produce chondrules, CAIs, refractory dust grains and other high-temperature materials observed in comets and meteorites. The solar bipolar jet flow may have produced an enrichment of 16O in the solar nebula over time and the chond...

  3. Myths of "shock therapy".

    Science.gov (United States)

    Fink, M

    1977-09-01

    The author discusses the myths of the ECT process--that shock and the convulsion are essential, memory loss and brain damage are inescapable, and little is known of the process--and assesses the fallacies in these ideas. Present views of the ECT process suggest that its mode of action in depression may best be described as a prolonged form of diencephalic stimulation, particularly useful to affect the hypothalamic dysfunctions that characterize depressive illness. The author emphasizes the need for further study of this treatment modality and for self-regulation by the profession.

  4. Gravitational shock waves and extreme magnetomaterial shock waves

    International Nuclear Information System (INIS)

    Lichnerowicz, Andre.

    1975-01-01

    Within an astrophysical context corresponding to high densities, a self-gravitating model is studied, which is the set of an extreme material medium of infinite conductivity and of a magnetic field. Corresponding shock waves generate necessarily, in general, gravitational shock waves [fr

  5. Shock Producers and Shock Absorbers in the Crisis

    OpenAIRE

    Sinn, Hans-Werner

    2009-01-01

    It is not surprising that the U.S. has been by far the world’s largest shock producer in this crisis. The big shock absorbers on the other hand were Japan, Russia and Germany, whose exports shrank more than their imports.

  6. Simulations of Converging Shock Collisions for Shock Ignition

    Science.gov (United States)

    Sauppe, Joshua; Dodd, Evan; Loomis, Eric

    2016-10-01

    Shock ignition (SI) has been proposed as an alternative to achieving high gain in inertial confinement fusion (ICF) targets. A central hot spot below the ignition threshold is created by an initial compression pulse, and a second laser pulse drives a strong converging shock into the fuel. The collision between the rebounding shock from the compression pulse and the converging shock results in amplification of the converging shock and increases the hot spot pressure above the ignition threshold. We investigate shock collision in SI drive schemes for cylindrical targets with a polystyrene foam interior using radiation-hydrodynamics simulations with the RAGE code. The configuration is similar to previous targets fielded on the Omega laser. The CH interior results in a lower convergence ratio and the cylindrical geometry facilitates visualization of the shock transit using an axial X-ray backlighter, both of which are important for comparison to potential experimental measurements. One-dimensional simulations are used to determine shock timing, and the effects of low mode asymmetries in 2D computations are also quantified. LA-UR-16-24773.

  7. 30th International Symposium on Shock Waves

    CERN Document Server

    Sadot, Oren; Igra, Ozer

    2017-01-01

    These proceedings collect the papers presented at the 30th International Symposium on Shock Waves (ISSW30), which was held in Tel-Aviv Israel from July 19 to July 24, 2015. The Symposium was organized by Ortra Ltd. The ISSW30 focused on the state of knowledge of the following areas: Nozzle Flow, Supersonic and Hypersonic Flows with Shocks, Supersonic Jets, Chemical Kinetics, Chemical Reacting Flows, Detonation, Combustion, Ignition, Shock Wave Reflection and Interaction, Shock Wave Interaction with Obstacles, Shock Wave Interaction with Porous Media, Shock Wave Interaction with Granular Media, Shock Wave Interaction with Dusty Media, Plasma, Magnetohyrdrodynamics, Re-entry to Earth Atmosphere, Shock Waves in Rarefied Gases, Shock Waves in Condensed Matter (Solids and Liquids), Shock Waves in Dense Gases, Shock Wave Focusing, Richtmyer-Meshkov Instability, Shock Boundary Layer Interaction, Multiphase Flow, Blast Waves, Facilities, Flow Visualization, and Numerical Methods. The two volumes serve as a reference ...

  8. Characterization and modification of cavitation pattern in shock wave lithotripsy

    Science.gov (United States)

    Arora, Manish; Ohl, Claus Dieter; Liebler, Marko

    2004-01-01

    The temporal and spatial dynamics of cavitation bubble cloud growth and collapse in extracorporeal shock wave lithotripsy (ESWL) is studied experimentally. The first objective is obtaining reproducible cloud patterns experimentally and comparing them with FDTD-calculations. Second, we describe a method to modify the cavitation pattern by timing two consecutive pressure waves at variable delays. It is found that the spatial and temporal dynamics of the cavitation bubble can be varied in large ranges. The ability to control cavitation dynamics allows discussing strategies for improvement of medical and biological applications of shock waves such as cell membrane poration and stone fragmentation.

  9. Molecular diagnostics of interstellar shocks

    International Nuclear Information System (INIS)

    Hartquist, T.W.; Oppenheimer, M.; Dalgarno, A.

    1980-01-01

    The chemistry of molecules in shocked regions of the interstellar gas is considered and calculations are carried out for a region subjected to a shock at a velocity of 8 km s -1 Substantial enhancements are predicted in the concentrations of the molecules H 2 S, SO, and SiO compared to those anticipated in cold interstellar clouds

  10. Molecular diagnostics of interstellar shocks

    Science.gov (United States)

    Hartquist, T. W.; Dalgarno, A.; Oppenheimer, M.

    1980-02-01

    The chemistry of molecules in shocked regions of the interstellar gas is considered and calculations are carried out for a region subjected to a shock at a velocity of 8 km/sec. Substantial enhancements are predicted in the concentrations of the molecules H2S, SO, and SiO compared to those anticipated in cold interstellar clouds.

  11. How Culture Shock Affects Communication.

    Science.gov (United States)

    Barna, LaRay M.

    The paper defines the term "culture shock" and discusses the changes that this state can make in a person's behavior. Culture shock refers to the emotional and physiological reaction of high activation that is brought about by sudden immersion in a new culture. Because one's own culture shields one from the unknown and reduces the need to make…

  12. Molecular diagnostics of interstellar shocks

    Science.gov (United States)

    Hartquist, T. W.; Dalgarno, A.; Oppenheimer, M.

    1980-01-01

    The chemistry of molecules in shocked regions of the interstellar gas is considered and calculations are carried out for a region subjected to a shock at a velocity of 8 km/sec. Substantial enhancements are predicted in the concentrations of the molecules H2S, SO, and SiO compared to those anticipated in cold interstellar clouds.

  13. Shock wave treatment in medicine

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 30; Issue 2 ... In the present paper we discuss the basic theory and application of shock waves and its history in medicine. The idea behind using shock wave therapy for orthopedic diseases is the stimulation of healing in tendons, surrounding tissue and bones. This is a ...

  14. Shock wave treatment in medicine

    Indian Academy of Sciences (India)

    Unknown

    to open surgery, the cost of the ESWT is very reasonable. But nevertheless it is necessary to improve the basic un ... In second group, shock waves are used to measure distances because of the low energy loss over large distances ... pared to a piezoelectric hydrophone. The rise time of an electrohydraulic generated shock ...

  15. Numerical modeling of slow shocks

    International Nuclear Information System (INIS)

    Winske, D.

    1987-01-01

    This paper reviews previous attempt and the present status of efforts to understand the structure of slow shocks by means of time dependent numerical calculations. Studies carried out using MHD or hybrid-kinetic codes have demonstrated qualitative agreement with theory. A number of unresolved issues related to hybrid simulations of the internal shock structure are discussed in some detail. 43 refs., 8 figs

  16. Dynamic shock wave: hammer blow

    International Nuclear Information System (INIS)

    Lackme, Claude

    1978-01-01

    The general properties of shocks, their generation and the conditions of reflexion to an interface are dealt with in turn. By then applying these concepts to a liquid column and its environment (wall, free area, closing devices) the hammer blow is presented as being a relatively weak shock [fr

  17. Slow shocks and their transition to fast shocks in the inner solar wind

    International Nuclear Information System (INIS)

    Wang, Y.C.

    1987-01-01

    The jump conditions of MHD shocks may be directly calculated as functions of three upstream conditions: the shock Alfven number based on the normal component of the relative shock speed, the shock angle, and the plasma β value. The shock Alfven number is less than 1 for a slow shock and greater than 1 for a fast shock. A traveling, forward shock can be a slow shock in coronal space, where the Alfven speed is of the order of 1000 km/s. The surface of a forward slow shock has a bow-shaped geometry with its nose facing toward the sun. The decrease in the Alfven speed at increasing heliocentric distance causes the shock Alfven number of a forward slow shock to become greater than 1, and the shock eventually evolves from a slow shock into a fast shock. During the transition the shock system consists of a slow shock, a fast shock, and a rotational discontinuity. They intersect along a closed transition line. As the system moves outward from the sun, the area enclosed by the transition line expands, the fast shock grows stronger, and the slow shock becomes weaker. Eventually, the slow shock diminishes, and the entire shock system evolves into a forward fast shock. copyrightAmerican Geophysical Union 1987

  18. Shocking matter to extreme conditions

    International Nuclear Information System (INIS)

    Gupta, Y.M.; Sharma, S.M.

    1997-01-01

    A good understanding of the thermodynamic response of matter at high compression and high energy densities is important to several areas of physics. Shock-wave experiments are uniquely suited for obtaining data at extreme conditions, and a shock-compressed matter can be viewed as a condensed system with or without dissociation or as a strongly coupled plasma. This article reviews work by Da Silva et al. in which irradiances ranging from 5x10 superscript 12 to 2x10 superscript 14 W/cm 2 were used to generate 8- to 10-ns square pulses in liquid deuterium. The authors demonstrated negligible pre-heating of the sample, steady propagation of the shock wave, and direct determination of the shock wave velocity along with particle velocity and density in the shocked state. Da Silva et al. results are compared with models and other experimental information, and the usefulness of the data in other areas is assessed. 11 refs., 1 fig

  19. Electron transport and shock ignition

    Energy Technology Data Exchange (ETDEWEB)

    Bell, A R; Tzoufras, M, E-mail: t.bell1@physics.ox.ac.uk [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2011-04-15

    Inertial fusion energy (IFE) offers one possible route to commercial energy generation. In the proposed 'shock ignition' route to fusion, the target is compressed at a relatively low temperature and then ignited using high intensity laser irradiation which drives a strong converging shock into the centre of the fuel. With a series of idealized calculations we analyse the electron transport of energy into the target, which produces the pressure responsible for driving the shock. We show that transport in shock ignition lies near the boundary between ablative and heat front regimes. Moreover, simulations indicate that non-local effects are significant in the heat front regime and might lead to increased efficiency by driving the shock more effectively and reducing heat losses to the plasma corona.

  20. Oscillating nonlinear acoustic shock waves

    DEFF Research Database (Denmark)

    Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

    2016-01-01

    We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show that at resona......We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

  1. Shock waves & explosions

    CERN Document Server

    Sachdev, PL

    2004-01-01

    Understanding the causes and effects of explosions is important to experts in a broad range of disciplines, including the military, industrial and environmental research, aeronautic engineering, and applied mathematics. Offering an introductory review of historic research, Shock Waves and Explosions brings analytic and computational methods to a wide audience in a clear and thorough way. Beginning with an overview of the research on combustion and gas dynamics in the 1970s and 1980s, the author brings you up to date by covering modeling techniques and asymptotic and perturbative methods and ending with a chapter on computational methods.Most of the book deals with the mathematical analysis of explosions, but computational results are also included wherever they are available. Historical perspectives are provided on the advent of nonlinear science, as well as on the mathematical study of the blast wave phenomenon, both when visualized as a point explosion and when simulated as the expansion of a high-pressure ...

  2. Analysis of shock implosion

    Energy Technology Data Exchange (ETDEWEB)

    Mishkin, E.A.; Alejaldre, C. (Polytechnic Inst. of New York, Brooklyn (USA))

    1984-06-01

    An imploding shock wave, coming from infinity, moves through an ideal gas with the adiabatic constant ..gamma... To define a single-valued self-similar coefficient over the whole classical interval 1<..gamma..

  3. The cosmic-ray shock structure problem for relativistic shocks

    Science.gov (United States)

    Webb, G. M.

    1985-01-01

    The time asymptotic behaviour of a relativistic (parallel) shock wave significantly modified by the diffusive acceleration of cosmic-rays is investigated by means of relativistic hydrodynamical equations for both the cosmic-rays and thermal gas. The form of the shock structure equation and the dispersion relation for both long and short wavelength waves in the system are obtained. The dependence of the shock acceleration efficiency on the upstream fluid spped, long wavelength Mach number and the ratio N = P sub co/cP sub co+P sub go)(Psub co and P sub go are the upstream cosmic-ray and thermal gas pressures respectively) are studied.

  4. Cosmic-ray shock acceleration in oblique MHD shocks

    Science.gov (United States)

    Webb, G. M.; Drury, L. OC.; Volk, H. J.

    1986-01-01

    A one-dimensional, steady-state hydrodynamical model of cosmic-ray acceleration at oblique MHD shocks is presented. Upstream of the shock the incoming thermal plasma is subject to the adverse pressure gradient of the accelerated particles, the J x B force, as well as the thermal gas pressure gradient. The efficiency of the acceleration of cosmic-rays at the shock as a function of the upstream magnetic field obliquity and upstream plasma beta is investigated. Astrophysical applications of the results are briefly discussed.

  5. Heat Shock Proteins in Tendinopathy: Novel Molecular Regulators

    Directory of Open Access Journals (Sweden)

    Neal L. Millar

    2012-01-01

    Full Text Available Tendon disorders—tendinopathies—are the primary reason for musculoskeletal consultation in primary care and account for up to 30% of rheumatological consultations. Whilst the molecular pathophysiology of tendinopathy remains difficult to interpret the disease process involving repetitive stress, and cellular load provides important mechanistic insight into the area of heat shock proteins which spans many disease processes in the autoimmune community. Heat shock proteins, also called damage-associated molecular patterns (DAMPs, are rapidly released following nonprogrammed cell death, are key effectors of the innate immune system, and critically restore homeostasis by promoting the reconstruction of the effected tissue. Our investigations have highlighted a key role for HSPs in tendion disease which may ultimately affect tissue rescue mechanisms in tendon pathology. This paper aims to provide an overview of the biology of heat shock proteins in soft tissue and how these mediators may be important regulators of inflammatory mediators and matrix regulation in tendinopathy.

  6. Chondrule destruction in nebular shocks

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, Emmanuel; Thompson, Christopher, E-mail: ejacquet@mnhn.fr [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George Street, Toronto, ON M5S 3H8 (Canada)

    2014-12-10

    Chondrules are millimeter-sized silicate spherules ubiquitous in primitive meteorites, but whose origin remains mysterious. One of the main proposed mechanisms for producing them is melting of solids in shock waves in the gaseous protoplanetary disk. However, evidence is mounting that chondrule-forming regions were enriched in solids well above solar abundances. Given the high velocities involved in shock models, destructive collisions would be expected between differently sized grains after passage of the shock front as a result of differential drag. We investigate the probability and outcome of collisions of particles behind a one-dimensional shock using analytic methods as well as a full integration of the coupled mass, momentum, energy, and radiation equations. Destruction of protochondrules seems unavoidable for solid/gas ratios ε ≳ 0.1, and possibly even for solar abundances because of 'sandblasting' by finer dust. A flow with ε ≳ 10 requires much smaller shock velocities (∼2 versus 8 km s{sup –1}) in order to achieve chondrule-melting temperatures, and radiation trapping allows slow cooling of the shocked fragments. Initial destruction would still be extensive; although re-assembly of millimeter-sized particles would naturally occur by grain sticking afterward, the compositional heterogeneity of chondrules may be difficult to reproduce. We finally note that solids passing through small-scale bow shocks around few kilometer-sized planetesimals might experience partial melting and yet escape fragmentation.

  7. Simulation of mechanical shock environments

    International Nuclear Information System (INIS)

    Lalanne, Christian.

    1975-07-01

    Shocks can produce a severe mechanical environment which must be taken into account when designing and developing new equipments. After some mathematical (Laplace and Fourier transforms) and mechanical recalls (response of a one degree freedom system to a sinusoidal excitation), different analysis methods are compared, these methods being the most used now to compare relative severities of tests and establish specifications. A few chapter deal with the different properties of simple, easy to produce, shock shapes. Then some now-in-use programmators or shock-machines specifications are shown. A final chapter concerns acceleration transducers [fr

  8. Particle acceleration in modified shocks

    International Nuclear Information System (INIS)

    Drury, L.O'C.; Axford, W.I.; Summers, D.

    1982-01-01

    Efficient particle acceleration in shocks must modify the shock structure with consequent changes in the particle acceleration. This effect is studied and analytic solutions are found describing the diffusive acceleration of particles with momentum independent diffusion coefficients in hyperbolic tangent type velocity transitions. If the input particle spectrum is a delta function, the shock smoothing replaces the truncated power-law downstream particle spectrum by a more complicated form, but one which has a power-law tail at high momenta. For a cold plasma this solution can be made completely self-consistent. Some problems associated with momentum dependent diffusion coefficients are discussed. (author)

  9. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    Full Text Available The subject of study. We examined the interaction of counterpropagating shock waves. The necessity of counterpropagating shock waves studying occurs at designing of high Mach number modern internal compression air intakes, Ramjets with subsonic and supersonic combustion, in asymmetrical supersonic nozzles and in some other cases. In a sense, this problem is a generalization of the case of an oblique shock reflection from the wall or from the plane of symmetry. With the renewed vigor, the interest to this problem emerged at the end of the 90s. This was due to the start of the programs for flight study at hypersonic speeds. The first experiments performed with air intakes, which realized the interaction of counterpropagating shock waves have shown that the change in flow velocity is accompanied by abrupt alteration of shock-wave structure, the occurrence of nonstationary and oscillatory phenomena. With an increase of flow velocity these phenomena undesirable for aircraft structure became more marked. The reason is that there are two fundamentally different modes of interaction of counterpropagating shock waves: a four-wave regular and a five-wave irregular. The transition from one mode to another can be nonstationary abrupt or gradual, it can also be accompanied by hysteresis. Main results. Criteria for the transition from regular reflection of counterpropagating shock waves to irregular are described: the criterion of von Neumann and the stationary Mach configuration criterion. We described areas in which the transition from one reflection type to another is possible only in abrupt way, as well as areas of possible gradual transition. Intensity dependences of the reflected shock waves from the intensity of interacting counterpropagating shocks were given. Qualitative pictures of shock-wave structures arising from the interaction of counterpropagating shock waves were shown. Calculation results of the intensity of outgoing gas

  10. Particle acceleration in modified shocks

    Energy Technology Data Exchange (ETDEWEB)

    Drury, L.O' C. (Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.)); Axford, W.I. (Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau (Germany, F.R.)); Summers, D. (Memorial Univ. of Newfoundland, St. John' s (Canada))

    1982-03-01

    Efficient particle acceleration in shocks must modify the shock structure with consequent changes in the particle acceleration. This effect is studied and analytic solutions are found describing the diffusive acceleration of particles with momentum independent diffusion coefficients in hyperbolic tangent type velocity transitions. If the input particle spectrum is a delta function, the shock smoothing replaces the truncated power-law downstream particle spectrum by a more complicated form, but one which has a power-law tail at high momenta. For a cold plasma this solution can be made completely self-consistent. Some problems associated with momentum dependent diffusion coefficients are discussed.

  11. Shocks in the Early Universe.

    Science.gov (United States)

    Pen, Ue-Li; Turok, Neil

    2016-09-23

    We point out a surprising consequence of the usually assumed initial conditions for cosmological perturbations. Namely, a spectrum of Gaussian, linear, adiabatic, scalar, growing mode perturbations not only creates acoustic oscillations of the kind observed on very large scales today, it also leads to the production of shocks in the radiation fluid of the very early Universe. Shocks cause departures from local thermal equilibrium as well as create vorticity and gravitational waves. For a scale-invariant spectrum and standard model physics, shocks form for temperatures 1  GeVUniverse as early as 10^{-30}  sec after the big bang.

  12. Simple, economical heat-shock devices for zebrafish housing racks.

    Science.gov (United States)

    Duszynski, Robert J; Topczewski, Jacek; LeClair, Elizabeth E

    2011-12-01

    One reason for the popularity of the zebrafish (Danio rerio) as a model vertebrate is the ability to manipulate gene expression in this organism. A common method is to induce gene expression transiently under control of a heat-shock promoter (e.g., hsp70l). By making simple mechanical adjustments to small aquarium heaters (25-50W), we were able to produce consistent and reliable heat-shock conditions within a conventional zebrafish housing system. Up to two heat-shock intervals per day (>37°C) could be maintained under conditions of continuous flow (5-25 mL/min). Temperature logging every 30 s indicated rapid warm up times, consistent heat-shock lengths, and accurate and precise peak water temperatures (mean±SD=38°C±0.2°C). The biological effects of these heat-shock treatments were confirmed by observing inducible expression of enhanced green fluorescent protein (EGFP) and inhibition of caudal fin regeneration in a transgenic fish line expressing a dominant negative fibroblast growth factor receptor (Tg(hsp70l:dnfgfr1-EGFP)(pd1)). These devices are inexpensive, easily modified, and can be calibrated to accommodate a variety of experimental designs. After setup on a programmable timer, the heaters require no intervention to produce consistent daily heat shocks, and all other standard care protocols can be followed in the fish facility. The simplicity and stability of these devices make them suitable for long-term heat shocks at any stage of the zebrafish lifecycle (>7 days postfertilization), and useful for both laboratory and classroom experiments on transgenic zebrafish.

  13. CALCULATION OF SHOCK-WAVE PULSE EFFECT ON OUTSTRETCHED SPINE

    Directory of Open Access Journals (Sweden)

    G. A. Esman

    2011-01-01

    Full Text Available Combined effects of a shock-wave pulse method and mechanotherapy on a spine is considered as an alternative to conservative and operative methods.Methodology for spinal disease treatment while applying a shock-wave therapy is characterized by the following specific features. Firstly, it is necessary to limit a penetration depth of shock pulses in a biological object in order to exclude damage to a spinal cord. Secondly, it is necessary to limit an energy flux density:Imax≤ 0,280 J∕m2and  pressure in focus:PFmax≤ 0,040 MPа,in order to exclude traumatizing of spinal tissue and only stimulate blood  circulation and metabolic processes in them.Where an acceptable value of the force acting on the inter-vertebral disc while a shock wave is passing is determined by the following formula: F max = PFmaxS = PFmax πr02 = 0,040 ∙106 ∙3,14 ∙(8∙10-32 = 9 N, where r0 – a focal spot radius, mm.Mechanotherapy is applied in combination with the shock-wave therapy and it presupposes the following: an outstretching force acts created in a longitudinal direction of the spine and it is directed across a vertebral column, whose value usually ranges from 50 to 500 N.   

  14. Endogenous versus exogenous shocks in systems with memory

    Science.gov (United States)

    Sornette, D.; Helmstetter, A.

    2003-02-01

    Systems with long-range persistence and memory are shown to exhibit different precursory as well as recovery patterns in response to shocks of exogenous versus endogenous origins. By endogenous, we envision either fluctuations resulting from an underlying chaotic dynamics or from a stochastic forcing origin which may be external or be an effective coarse-grained description of the microscopic fluctuations. In this scenario, endogenous shocks result from a kind of constructive interference of accumulated fluctuations whose impacts survive longer than the large shocks themselves. As a consequence, the recovery after an endogenous shock is in general slower at early times and can be at long times either slower or faster than after an exogenous perturbation. This offers the tantalizing possibility of distinguishing between an endogenous versus exogenous cause of a given shock, even when there is no “smoking gun”. This could help in investigating the exogenous versus self-organized origins in problems such as the causes of major biological extinctions, of change of weather regimes and of the climate, in tracing the source of social upheaval and wars, and so on. Sornette et al., Volatility fingerprints of large stocks: endogenous versus exogenous, cond-mat/0204626 has already shown how this concept can be applied concretely to differentiate the effects on financial markets of the 11 September 2001 attack or of the coup against Gorbachev on 19 August 1991 (exogenous) from financial crashes such as October 1987 (endogenous).

  15. Shock parameter calculations at weak interplanetary shock waves

    Directory of Open Access Journals (Sweden)

    J. M. Gloag

    2005-02-01

    Full Text Available A large set of interplanetary shock waves observed using the Ulysses spacecraft is analysed in order to determine their local parameters. For the first time a detailed analysis is extended to the thermodynamic properties of a large number of events. The intention is to relate the shock parameters to the requirements set by MHD shock theory. A uniform approach is adopted in the selection of up and downstream regions for this analysis and applied to all the shock waves. Initially, the general case of a 3 component adiabatic plasma is considered. However, the calculation of magnetosonic and Alfvénic Mach numbers and the ratio of downstream to upstream entropy produce some unexpected results. In some cases there is no clear increase in entropy across the shock and also the magnetosonic Mach number can be less than 1. It is found that a more discerning use of data along with an empirical value for the polytropic index can raise the distribution of downstream to upstream entropy ratios to a more acceptable level. However, it is also realised that many of these shocks are at the very weakest end of the spectrum and associated phenomena may also contribute to the explanation of these results.

  16. Quasilinear simulations of interplanetary shocks and Earth's bow shock

    Science.gov (United States)

    Afanasiev, Alexandr; Battarbee, Markus; Ganse, Urs; Vainio, Rami; Palmroth, Minna; Pfau-Kempf, Yann; Hoilijoki, Sanni; von Alfthan, Sebastian

    2016-04-01

    We have developed a new self-consistent Monte Carlo simulation model for particle acceleration in shocks. The model includes a prescribed large-scale magnetic field and plasma density, temperature and velocity profiles and a self-consistently computed incompressible ULF foreshock under the quasilinear approximation. Unlike previous analytical treatments, our model is time dependent and takes full account of the anisotropic particle distributions and scattering in the wave-particle interaction process. We apply the model to the problem of particle acceleration at traveling interplanetary (IP) shocks and Earth's bow shock and compare the results with hybrid-Vlasov simulations and spacecraft observations. A qualitative agreement in terms of spectral shape of the magnetic fluctuations and the polarization of the unstable mode is found between the models and the observations. We will quantify the differences of the models and explore the region of validity of the quasilinear approach in terms of shock parameters. We will also compare the modeled IP shocks and the bow shock, identifying the similarities and differences in the spectrum of accelerated particles and waves in these scenarios. The work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324 (HESPERIA). The Academy of Finland is thanked for financial support. We acknowledge the computational resources provided by CSC - IT Centre for Science Ltd., Espoo.

  17. Diaphragmless shock wave generators for industrial applications of shock waves

    Science.gov (United States)

    Hariharan, M. S.; Janardhanraj, S.; Saravanan, S.; Jagadeesh, G.

    2011-06-01

    The prime focus of this study is to design a 50 mm internal diameter diaphragmless shock tube that can be used in an industrial facility for repeated loading of shock waves. The instantaneous rise in pressure and temperature of a medium can be used in a variety of industrial applications. We designed, fabricated and tested three different shock wave generators of which one system employs a highly elastic rubber membrane and the other systems use a fast acting pneumatic valve instead of conventional metal diaphragms. The valve opening speed is obtained with the help of a high speed camera. For shock generation systems with a pneumatic cylinder, it ranges from 0.325 to 1.15 m/s while it is around 8.3 m/s for the rubber membrane. Experiments are conducted using the three diaphragmless systems and the results obtained are analyzed carefully to obtain a relation between the opening speed of the valve and the amount of gas that is actually utilized in the generation of the shock wave for each system. The rubber membrane is not suitable for industrial applications because it needs to be replaced regularly and cannot withstand high driver pressures. The maximum shock Mach number obtained using the new diaphragmless system that uses the pneumatic valve is 2.125 ± 0.2%. This system shows much promise for automation in an industrial environment.

  18. Shock wave dynamics derivatives and related topics

    CERN Document Server

    Emanuel, George

    2012-01-01

    "...this monograph develops an esoteric niche within shock wave theory. …treats shock waves from an analytical approach assuming perfect gas. Emanuel has made significant contributions to the theory of shock waves and has selected a number of topics that reflect those contributions."-Shock Waves, 2013.

  19. Forkhead Box M1 Is Regulated by Heat Shock Factor 1 and Promotes Glioma Cells Survival under Heat Shock Stress*

    Science.gov (United States)

    Dai, Bingbing; Gong, Aihua; Jing, Zhitao; Aldape, Kenneth D.; Kang, Shin-Hyuk; Sawaya, Raymond; Huang, Suyun

    2013-01-01

    The forkhead box M1 (FoxM1) is a key transcription factor regulating multiple aspects of cell biology. Prior studies have shown that FoxM1 is overexpressed in a variety of human tumors, including brain tumor, and plays a critical role in cancer development and progression. In this study we found that FoxM1 was up-regulated by heat shock factor 1 (HSF1) under heat shock stress condition in multiple cell lines. Knockdown of HSF1 with HSF1 siRNA or inhibition of HSF1 with a HSF1 inhibitor abrogated heat shock-induced expression of FoxM1. Genetic deletion of HSF1 in mouse embryo fibroblast cells also abolished heat shock stress-induced FoxM1 expression. Moreover, we showed that HSF1 directly bound to FoxM1 promoter and increased FoxM1 promoter activity. Furthermore, we demonstrated that FoxM1 was required for the G2-M phase progression through regulating Cdc2, Cdc20, and Cdc25B under a mild heat shock stress but enhanced cell survival under lethal heat shock stress condition. Finally, in human glioblastoma specimens, FoxM1 overexpression correlated with elevated HSF1 expression. Our results indicate that FoxM1 is regulated by HSF1 and is critical for HSF1-mediated heat shock response. We demonstrated a novel mechanism of stress resistance controlled by HSF1 and a new HSF-FoxM1 connection that mediates cellular thermotolerance. PMID:23192351

  20. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    Almost all natural phenomena, and social and economic changes, .... reference moving with velocity c also by the same symbol x and ... abstract as can be seen from the publication of the book Shock Waves and Reaction Diffusion Equation.

  1. Shock Thermodynamic Applied Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Shock Thermodynamic Applied Research Facility (STAR) facility, within Sandia’s Solid Dynamic Physics Department, is one of a few institutions in the world with a...

  2. Target design for shock ignition

    International Nuclear Information System (INIS)

    Schurtz, G; Ribeyre, X; Lafon, M

    2010-01-01

    The conventional approach of laser driven inertial fusion involves the implosion of cryogenic shells of deuterium-tritium ice. At sufficiently high implosion velocities, the fuel ignites by itself from a central hot spot. In order to reduce the risks of hydrodynamic instabilities inherent to large implosion velocities, it was proposed to compress the fuel at low velocity, and ignite the compressed fuel by means of a convergent shock wave driven by an intense spike at the end of the laser pulse. This scheme, known as shock ignition, reduces the risks of shell break-up during the acceleration phase, but it may be impeded by a low coupling efficiency of the laser pulse with plasma at high intensities. This work provides a relationship between the implosion velocity and the laser intensity required to ignite the target by a shock. The operating domain of shock ignition at different energies is described.

  3. Undercuts by Laser Shock Forming

    International Nuclear Information System (INIS)

    Wielage, Hanna; Vollertsen, Frank

    2011-01-01

    In laser shock forming TEA-CO 2 -laser induced shock waves are used to form metal foils, such as aluminum or copper. The process utilizes an initiated plasma shock wave on the target surface, which leads to a forming of the foil. A challenge in forming technologies is the manufacturing of undercuts. By conventional forming methods these special forms are not feasible. In this article, it is presented that undercuts in the micro range can be produced by laser shock deep drawing. Different drawing die diameters, drawing die depths and the material aluminum in the thicknesses 20 and 50 μm were investigated. It will be presented that smaller die diameters facilitate undercuts compared to bigger die diameters. The phenomena can be explained by Barlow's formula. Furthermore, it is shown which maximum undercut depth at different die diameters can be reached. To this end, cross-sections of the different parameter combinations are displayed.

  4. Electric Shock Injuries in Children

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Electric Shock Injuries in Children Page Content ​When the ... comes into direct contact with a source of electricity, the current passes through it, producing what's called ...

  5. Relativistic shocks and particle acceleration

    International Nuclear Information System (INIS)

    Heavens, A.F.

    1988-01-01

    In this paper, we investigate the fluid dynamics of relativistic shock waves, and use the results to calculate the spectral index of particles accelerated by the Fermi process in such shocks. We have calculated the distributions of Fermi-accelerated particles at shocks propagating into cold proton-electron plasma and also cold electron-positron plasma. We have considered two different power spectra for the scattering waves, and find, in contrast to the non-relativistic case, that the spectral index of the accelerated particles depends on the wave power spectrum. On the assumption of thermal equilibrium both upstream and downstream, we present some useful fits for the compression ratio of shocks propagating at arbitrary speeds into gas of any temperature. (author)

  6. Shock wave interaction with turbulence: Pseudospectral simulations

    International Nuclear Information System (INIS)

    Buckingham, A.C.

    1986-01-01

    Shock waves amplify pre-existing turbulence. Shock tube and shock wave boundary layer interaction experiments provide qualitative confirmation. However, shock pressure, temperature, and rapid transit complicate direct measurement. Computational simulations supplement the experimental data base and help isolate the mechanisms responsible. Simulations and experiments, particularly under reflected shock wave conditions, significantly influence material mixing. In these pseudospectral Navier-Stokes simulations the shock wave is treated as either a moving (tracked or fitted) domain boundary. The simulations assist development of code mix models. Shock Mach number and pre-existing turbulence intensity initially emerge as key parameters. 20 refs., 8 figs

  7. The Efficacy of Cognitive Shock

    Science.gov (United States)

    2015-05-21

    way, causing dissonance or cognitive conflict, so that the mental model has to be ‘accommodated’ to the new data. Categories and knowledge have to...The Efficacy of Cognitive Shock A Monograph by MAJ Anthony L. Marston United States Army School of Advanced Military Studies...DATES COVERED (From - To) JUN 2014 – MAY 2015 4. TITLE AND SUBTITLE The Efficacy of Cognitive Shock 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  8. Pressurized Thermal Shock, Pts

    International Nuclear Information System (INIS)

    Boyd, C.

    2008-01-01

    Pressurized Thermal Shock (Pts) refers to a condition that challenges the integrity of the reactor pressure vessel. The root cause of this problem is the radiation embrittlement of the reactor vessel. This embrittlement leads to an increase in the reference temperature for nil ductility transition (RTNDT). RTNDT can increase to the point where the reactor vessel material can loose fracture toughness during overcooling events. The analysis of the risk of having a Pts for a specific plant is a multi-disciplinary problem involving probabilistic risk analysis (PRA), thermal-hydraulic analysis, and ultimately a structural and fracture analysis of the vessel wall. The PRA effort involves the postulation of overcooling events and ultimately leads to an integrated risk analysis. The thermal-hydraulic effort involves the difficult task of predicting the system behavior during a postulated overcooling scenario with a special emphasis on predicting the thermal and mechanic loadings on the reactor pressure vessel wall. The structural and fracture analysis of the reactor vessel wall relies on the thermal-hydraulic conditions as boundary conditions. The US experience has indicated that medium and large diameter primary system breaks dominate the risk of Pts along with scenarios that involve a stuck open valve (and associated system cooldown) that recloses resulting in system re-pressurization while the vessel wall is cool.

  9. Sepsis and septic shock

    Science.gov (United States)

    Hotchkiss, Richard S.; Moldawer, Lyle L.; Opal, Steven M.; Reinhart, Konrad; Turnbull, Isaiah R.; Vincent, Jean-Louis

    2017-01-01

    For more than two decades, sepsis was defined as a microbial infection that produces fever (or hypothermia), tachycardia, tachypnoea and blood leukocyte changes. Sepsis is now increasingly being considered a dysregulated systemic inflammatory and immune response to microbial invasion that produces organ injury for which mortality rates are declining to 15–25%. Septic shock remains defined as sepsis with hyperlactataemia and concurrent hypotension requiring vasopressor therapy, with in-hospital mortality rates approaching 30–50%. With earlier recognition and more compliance to best practices, sepsis has become less of an immediate life-threatening disorder and more of a long-term chronic critical illness, often associated with prolonged inflammation, immune suppression, organ injury and lean tissue wasting. Furthermore, patients who survive sepsis have continuing risk of mortality after discharge, as well as long-term cognitive and functional deficits. Earlier recognition and improved implementation of best practices have reduced in-hospital mortality, but results from the use of immunomodulatory agents to date have been disappointing. Similarly, no biomarker can definitely diagnose sepsis or predict its clinical outcome. Because of its complexity, improvements in sepsis outcomes are likely to continue to be slow and incremental. PMID:28117397

  10. Focusing of Shear Shock Waves

    Science.gov (United States)

    Giammarinaro, Bruno; Espíndola, David; Coulouvrat, François; Pinton, Gianmarco

    2018-01-01

    Focusing is a ubiquitous way to transform waves. Recently, a new type of shock wave has been observed experimentally with high-frame-rate ultrasound: shear shock waves in soft solids. These strongly nonlinear waves are characterized by a high Mach number, because the shear wave velocity is much slower, by 3 orders of magnitude, than the longitudinal wave velocity. Furthermore, these waves have a unique cubic nonlinearity which generates only odd harmonics. Unlike longitudinal waves for which only compressional shocks are possible, shear waves exhibit cubic nonlinearities which can generate positive and negative shocks. Here we present the experimental observation of shear shock wave focusing, generated by the vertical motion of a solid cylinder section embedded in a soft gelatin-graphite phantom to induce linearly vertically polarized motion. Raw ultrasound data from high-frame-rate (7692 images per second) acquisitions in combination with algorithms that are tuned to detect small displacements (approximately 1 μ m ) are used to generate quantitative movies of gel motion. The features of shear shock wave focusing are analyzed by comparing experimental observations with numerical simulations of a retarded-time elastodynamic equation with cubic nonlinearities and empirical attenuation laws for soft solids.

  11. Shock compression of synthetic opal

    International Nuclear Information System (INIS)

    Inoue, A; Okuno, M; Okudera, H; Mashimo, T; Omurzak, E; Katayama, S; Koyano, M

    2010-01-01

    Structural change of synthetic opal by shock-wave compression up to 38.1 GPa has been investigated by using SEM, X-ray diffraction method (XRD), Infrared (IR) and Raman spectroscopies. Obtained information may indicate that the dehydration and polymerization of surface silanole due to high shock and residual temperature are very important factors in the structural evolution of synthetic opal by shock compression. Synthetic opal loses opalescence by 10.9 and 18.4 GPa of shock pressures. At 18.4 GPa, dehydration and polymerization of surface silanole and transformation of network structure may occur simultaneously. The 4-membered ring of TO 4 tetrahedrons in as synthetic opal may be relaxed to larger ring such as 6-membered ring by high residual temperature. Therefore, the residual temperature may be significantly high at even 18.4 GPa of shock compression. At 23.9 GPa, opal sample recovered the opalescence. Origin of this opalescence may be its layer structure by shock compression. Finally, sample fuse by very high residual temperature at 38.1 GPa and the structure closes to that of fused SiO 2 glass. However, internal silanole groups still remain even at 38.1 GPa.

  12. Computations of slowly moving shocks

    International Nuclear Information System (INIS)

    Karni, S.; Canic, S.

    1997-01-01

    Computations of slowly moving shocks by shock capturing schemes may generate oscillations are generated already by first-order schemes, but become more pronounced in higher-order schemes which seem to exhibit different behaviors: (i) the first-order upwind (UW) scheme which generates strong oscillations and (ii) the Lax-Friedrichs scheme which appears not to generate any disturbances at all. A key observation is that in the UW case, the numerical viscosity in the shock family vanishes inside the slow shock layer. Simple scaling arguments show the third-order effects on the solution may no longer be neglected. We derive the third-order modified equation for the UW scheme and regard the oscillatory solution as a traveling wave solution of the parabolic modified equation for the perturbation. We then look at the governing equation for the perturbation, which points to a plausible mechanism by which postshock oscillations are generated. It contains a third-order source term that becomes significant inside the shock layer, and a nonlinear coupling term which projects the perturbation on all characteristic fields, including those not associated with the shock family. 5 refs., 8 figs

  13. Shock compression of synthetic opal

    Science.gov (United States)

    Inoue, A.; Okuno, M.; Okudera, H.; Mashimo, T.; Omurzak, E.; Katayama, S.; Koyano, M.

    2010-03-01

    Structural change of synthetic opal by shock-wave compression up to 38.1 GPa has been investigated by using SEM, X-ray diffraction method (XRD), Infrared (IR) and Raman spectroscopies. Obtained information may indicate that the dehydration and polymerization of surface silanole due to high shock and residual temperature are very important factors in the structural evolution of synthetic opal by shock compression. Synthetic opal loses opalescence by 10.9 and 18.4 GPa of shock pressures. At 18.4 GPa, dehydration and polymerization of surface silanole and transformation of network structure may occur simultaneously. The 4-membered ring of TO4 tetrahedrons in as synthetic opal may be relaxed to larger ring such as 6-membered ring by high residual temperature. Therefore, the residual temperature may be significantly high at even 18.4 GPa of shock compression. At 23.9 GPa, opal sample recovered the opalescence. Origin of this opalescence may be its layer structure by shock compression. Finally, sample fuse by very high residual temperature at 38.1 GPa and the structure closes to that of fused SiO2 glass. However, internal silanole groups still remain even at 38.1 GPa.

  14. Shock compression of synthetic opal

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, A; Okuno, M; Okudera, H [Department of Earth Sciences, Kanazawa University Kanazawa, Ishikawa, 920-1192 (Japan); Mashimo, T; Omurzak, E [Shock Wave and Condensed Matter Research Center, Kumamoto University, Kumamoto, 860-8555 (Japan); Katayama, S; Koyano, M, E-mail: okuno@kenroku.kanazawa-u.ac.j [JAIST, Nomi, Ishikawa, 923-1297 (Japan)

    2010-03-01

    Structural change of synthetic opal by shock-wave compression up to 38.1 GPa has been investigated by using SEM, X-ray diffraction method (XRD), Infrared (IR) and Raman spectroscopies. Obtained information may indicate that the dehydration and polymerization of surface silanole due to high shock and residual temperature are very important factors in the structural evolution of synthetic opal by shock compression. Synthetic opal loses opalescence by 10.9 and 18.4 GPa of shock pressures. At 18.4 GPa, dehydration and polymerization of surface silanole and transformation of network structure may occur simultaneously. The 4-membered ring of TO{sub 4} tetrahedrons in as synthetic opal may be relaxed to larger ring such as 6-membered ring by high residual temperature. Therefore, the residual temperature may be significantly high at even 18.4 GPa of shock compression. At 23.9 GPa, opal sample recovered the opalescence. Origin of this opalescence may be its layer structure by shock compression. Finally, sample fuse by very high residual temperature at 38.1 GPa and the structure closes to that of fused SiO{sub 2} glass. However, internal silanole groups still remain even at 38.1 GPa.

  15. Electromagnetically driven radiative shocks and their measurements

    International Nuclear Information System (INIS)

    Kondo, K.; Watanabe, M.; Nakajima, M.; Kawamura, T.; Horioka, K.

    2005-01-01

    Experimental results on a generation of strong shocks in a compact pulse power device are reported. The characteristics of strong shocks are different from hydrodynamical shocks' because they depend on not only collisions but radiation processes. Radiative shocks are relevant to high energy density phenomena such as the explosions of supernovae. When initial pressure is lower than about 50 mtorr, an interesting structure is confirmed at the shock front, which might indicate a phenomenon proceeded by the radiative process. (author)

  16. Pressurized thermal shock (PTS)

    International Nuclear Information System (INIS)

    Rosso, Ricardo D.; Ventura, Mirta A.

    2006-01-01

    In the present work, a description of Thermal Shock in Pressurized conditions (PTS), and its influence in the treatment of the integrity of the pressure vessel (RPV) of a Pressurized Water Reactor (PWR) and/or of a Heavy water Pressurized water Reactor (PHWR) is made. Generally, the analysis of PTS involves a process of three stages: a-) Modeling with a System Code of relevant thermohydraulics transients in reference with the thermal shock; b-) The local distribution of temperatures in the downcomer and the heat transference coefficients from the RPV wall to the fluid, are determined; c-) The fracture mechanical analysis. These three stages are included in this work: Results with the thermohydraulics code Relap5/mod.3, are obtained, for a LOCA scenario in the hot leg of the cooling System of the Primary System of the CAN-I reactor. The method used in obtaining results is described. A study on the basis of lumped parameters of the local evolutions of the temperature of the flow is made, in the downcomer of the reactor pressure vessel. The purpose of this study is to determine how the intensification of the stress coefficient, varies in function of the emergency injected water during the thermohydraulic transients that take place under the imposed conditions in the postulated scene. Specially, it is considered a 50 cm 2 break, located in the neighborhoods of the pressurized with the corresponding hot leg connection. This size is considered like the most critical. The method used to obtain the results is described. The fracture mechanical analysis is made. From the obtained results we confirmed that we have a simple tool of easy application in order to analyze phenomena of the type PTS in the postulated scenes by break in the cold and hot legs of the primary system. This methodology of calculus is completely independent of the used ones by the Nucleoelectrica Argentina S.A. (NASA) in the analysis of the PTS phenomena in the CAN-I. The results obtained with the adopted

  17. Effect of endotoxin shock on the elimination of /sup 133/Xe by the lungs

    Energy Technology Data Exchange (ETDEWEB)

    Toth, T [Semmelweis Orvostudomanyi Egyetem, Budapest (Hungary); Spett, B; Bertok, L [Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszseguegyi Kutato Intezet, Budapest (Hungary); Vittay, P; Kopcsanyi, Zs; Jakab, T [Orvostovabbkepzoe Intezet, Budapest (Hungary)

    1979-07-01

    Experimental shock was induced in rats by the administration of 2 mg E.coli 089 endotoxin. 3 hours later 6.142 MBq /sup 133/Xe, dissolved in 1 ml physiological saline, was administered and the changes of radioactivity were followed over the lungs by a gamma-camera. The biological half-life of the isotope was 1.06 s in the control animals and 1.69 s in the animals in shock.

  18. Radiation- and pair-loaded shocks

    Science.gov (United States)

    Lyutikov, Maxim

    2018-06-01

    We consider the structure of mildly relativistic shocks in dense media, taking into account the radiation and pair loading, and diffusive radiation energy transfer within the flow. For increasing shock velocity (increasing post-shock temperature), the first important effect is the efficient energy redistribution by radiation within the shock that leads to the appearance of an isothermal jump, whereby the flow reaches the final state through a discontinuous isothermal transition. The isothermal jump, on scales much smaller than the photon diffusion length, consists of a weak shock and a quick relaxation to the isothermal conditions. Highly radiation-dominated shocks do not form isothermal jump. Pair production can mildly increase the overall shock compression ratio to ≈10 (4 for matter-dominated shocks and 7 of the radiation-dominated shocks).

  19. Prediction of massive bleeding. Shock index and modified shock index.

    Science.gov (United States)

    Terceros-Almanza, L J; García-Fuentes, C; Bermejo-Aznárez, S; Prieto-Del Portillo, I J; Mudarra-Reche, C; Sáez-de la Fuente, I; Chico-Fernández, M

    2017-12-01

    To determine the predictive value of the Shock Index and Modified Shock Index in patients with massive bleeding due to severe trauma. Retrospective cohort. Severe trauma patient's initial attention at the intensive care unit of a tertiary hospital. Patients older than 14 years that were admitted to the hospital with severe trauma (Injury Severity Score >15) form January 2014 to December 2015. We studied the sensitivity (Se), specificity (Sp), positive and negative predictive value (PV+ and PV-), positive and negative likelihood ratio (LR+ and LR-), ROC curves (Receiver Operating Characteristics) and the area under the same (AUROC) for prediction of massive hemorrhage. 287 patients were included, 76.31% (219) were male, mean age was 43,36 (±17.71) years and ISS was 26 (interquartile range [IQR]: 21-34). The overall frequency of massive bleeding was 8.71% (25). For Shock Index: AUROC was 0.89 (95% confidence intervals [CI] 0.84 to 0.94), with an optimal cutoff at 1.11, Se was 91.3% (95% CI: 73.2 to 97.58) and Sp was 79.69% (95% CI: 74.34 to 84.16). For the Modified Shock Index: AUROC was 0.90 (95% CI: 0.86 to 0.95), with an optimal cutoff at 1.46, Se was 95.65% (95% CI: 79.01 to 99.23) and Sp was 75.78% (95% CI: 70.18 to 80.62). Shock Index and Modified Shock Index are good predictors of massive bleeding and could be easily incorporated to the initial workup of patients with severe trauma. Copyright © 2017 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  20. Shock diffraction in alumina powder

    International Nuclear Information System (INIS)

    Venz, G.; Killen, P.D.; Page, N.W.

    1996-01-01

    In order to produce complex shaped components by dynamic compaction of ceramic powders detailed knowledge of their response under shock loading conditions is required. This work attempts to provide data on release effects and shock attenuation in 1 μm and 5 μm α-alumina powders which were compacted to between 85 % and 95 % of the solid phase density by the impact of high velocity steel projectiles. As in previous work, the powder was loaded into large cylindrical dies with horizontal marker layers of a contrasting coloured powder to provide a record of powder displacement in the recovered specimens. After recovery and infiltration with a thermosetting resin the specimens were sectioned and polished to reveal the structure formed by the passage of the projectile and shock wave. Results indicate that the shock pressures generated were of the order of 0.5 to 1.4 GPa and higher, with shock velocities and sound speeds in the ranges 650 to 800 m/s and 350 to 400 m/s respectively

  1. Transient shocks beyond the heliopause

    International Nuclear Information System (INIS)

    Fermo, R L; Pogorelov, N V; Burlaga, L F

    2015-01-01

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations. (paper)

  2. Energetic ion acceleration at collisionless shocks

    Science.gov (United States)

    Decker, R. B.; Vlahos, L.

    1985-01-01

    An example is presented from a test particle simulation designed to study ion acceleration at oblique turbulent shocks. For conditions appropriate at interplanetary shocks near 1 AU, it is found that a shock with theta sub B n = 60 deg is capable of producing an energy spectrum extending from 10 keV to approx. 1 MeV in approx 1 hour. In this case total energy gains result primarily from several separate episodes of shock drift acceleration, each of which occurs when particles are scattered back to the shock by magnetic fluctuations in the shock vicinity.

  3. Energetic ion acceleration at collisionless shocks

    International Nuclear Information System (INIS)

    Decker, R.B.; Vlahos, L.

    1985-01-01

    An example is presented from a test particle simulation designed to study ion acceleration at oblique turbulent shocks. For conditions appropriate at interplanetary shocks near 1 AU, it is found that a shock with theta sub B n = 60 deg is capable of producing an energy spectrum extending from 10 keV to approx 1 MeV in approx 1 hour. In this case total energy gains result primarily from several separate episodes of shock drift acceleration, each of which occurs when particles are scattered back to the shock by magnetic fluctuations in the shock vicinity

  4. Why the Nature of Oil Shocks Matters

    International Nuclear Information System (INIS)

    Archanskaia, Elizaveta; Hubert, Paul; Creel, Jerome

    2009-03-01

    This article studies the impact of oil shocks on the macro-economy in two ways insofar unexploited in the literature. The analysis is conducted at the global level, and it explicitly accounts for the potentially changing nature of oil shocks. Based on an original world GDP series and a grouping of oil shocks according to their nature, we find that oil supply shocks negatively impact world growth, contrary to oil demand shocks, pro-cyclical in their nature. This result is robust at the national level for the US. Furthermore, endogenous monetary policy is shown to have no counter-cyclical effects in the context of an oil demand shock. (authors)

  5. MHD intermediate shock discontinuities: Pt. 1

    International Nuclear Information System (INIS)

    Kennel, C.F.; Blandford, R.D.; Coppi, P.

    1989-01-01

    Recent numerical investigations have focused attention once more on the role of intermediate shocks in MHD. Four types of intermediate shock are identified using a graphical representation of the MHD Rankine-Hugoniot conditions. This same representation can be used to exhibit the close relationship of intermediate shocks to switch-on shocks and rotational discontinuities. The conditions under which intermediate discontinuities can be found are elucidated. The variations in velocity, pressure, entropy and magnetic-field jumps with upstream parameters in intermediate shocks are exhibited graphically. The evolutionary arguments traditionally advanced against intermediate shocks may fail because the equations of classical MHD are not strictly hyperbolic. (author)

  6. Shock waves in weakly compressed granular media.

    Science.gov (United States)

    van den Wildenberg, Siet; van Loo, Rogier; van Hecke, Martin

    2013-11-22

    We experimentally probe nonlinear wave propagation in weakly compressed granular media and observe a crossover from quasilinear sound waves at low impact to shock waves at high impact. We show that this crossover impact grows with the confining pressure P0, whereas the shock wave speed is independent of P0-two hallmarks of granular shocks predicted recently. The shocks exhibit surprising power law attenuation, which we model with a logarithmic law implying that shock dissipation is weak and qualitatively different from other granular dissipation mechanisms. We show that elastic and potential energy balance in the leading part of the shocks.

  7. Shock, diaschisis and von Monakow

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    2013-07-01

    Full Text Available The concept of shock apparently emerged in the middle of the 18th century (Whyett as an occurrence observed experimentally after spinal cord transection, and identified as "shock" phenomenon one century later (Hall. The concept was extended (Brown-Séquard and it was suggested that brain lesions caused functional rupture in regions distant from the injured one ("action à distance". The term "diaschisis" (von Monakow, proposed as a new modality of shock, had its concept broadened, underpinned by observations of patients, aiming at distinguishing between symptoms of focal brain lesions and transitory effects they produced, attributable to depression of distant parts of the brain connected to the injured area. Presently, diaschisis is related mainly to cerebrovascular lesions and classified according to the connection fibers involved, as proposed by von Monakow. Depression of metabolism and blood flow in regions anatomically separated, but related by connections with the lesion, allows observing diaschisis with neuroimaging.

  8. Shock compression of geological materials

    International Nuclear Information System (INIS)

    Kirk, S; Braithwaite, C; Williamson, D; Jardine, A

    2014-01-01

    Understanding the shock compression of geological materials is important for many applications, and is particularly important to the mining industry. During blast mining the response to shock loading determines the wave propagation speed and resulting fragmentation of the rock. The present work has studied the Hugoniot of two geological materials; Lake Quarry Granite and Gosford Sandstone. For samples of these materials, the composition was characterised in detail. The Hugoniot of Lake Quarry Granite was predicted from this information as the material is fully dense and was found to be in good agreement with the measured Hugoniot. Gosford Sandstone is porous and undergoes compaction during shock loading. Such behaviour is similar to other granular material and we show how it can be described using a P-a compaction model.

  9. Shock compression of simulated adobe

    Science.gov (United States)

    Braithwaite, C. H.; Church, P. D.; Gould, P. J.; Stewart, B.; Jardine, A. P.

    2017-01-01

    A series of plate impact experiments were conducted to investigate the shock response of a simulant for adobe, a traditional form of building material widely used around the world. Air dried bricks were sourced from the London brick company, dry machined and impacted at a range of velocities in a single stage gas gun. The shock Hugoniot was determined (Us =2.26up+0.37) as well as release information. The material was found to behave in a manner which was similar to that of loose sand and considerably less stiff than a weak porous sandstone. The effect of any cementing of the grains was examined by shocking powdered samples contained within a cell arrangement.

  10. Shock Initiation of Damaged Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Chidester, S K; Vandersall, K S; Tarver, C M

    2009-10-22

    Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

  11. Shock compaction of molybdenum powder

    Science.gov (United States)

    Ahrens, T. J.; Kostka, D.; Vreeland, T., Jr.; Schwarz, R. B.; Kasiraj, P.

    1983-01-01

    Shock recovery experiments which were carried out in the 9 to 12 GPa range on 1.4 distension Mo and appear adequate to compact to full density ( 45 (SIGMA)m) powders were examined. The stress levels, however, are below those calculated to be from 100 to approx. 22 GPa which a frictional heating model predicts are required to consolidate approx. 10 to 50 (SIGMA)m particles. The model predicts that powders that have a distension of m=1.6 shock pressures of 14 to 72 GPa are required to consolidate Mo powders in the 50 to 10 (SIGMA)m range.

  12. Cation disorder in shocked orthopyroxene.

    Science.gov (United States)

    Dundon, R. W.; Hafner, S. S.

    1971-01-01

    The study of cation distributions over nonequivalent lattice sites in minerals may reveal information on the history of temperature and pressure in rocks. Chemically homogeneous orthopyroxene specimens were shocked under well-controlled conditions in the laboratory in order to provide a basis for the interpretation of more complex natural materials. As a result of the investigation it is concluded that the distribution of magnesium and iron over the M1 and M2 positions in Bamle enstatite shocked at 1 megabar is highly disordered. It corresponds to an equilibrium distribution of at least 1000 C.

  13. Sepsis and Septic Shock Strategies.

    Science.gov (United States)

    Armstrong, Bracken A; Betzold, Richard D; May, Addison K

    2017-12-01

    Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Shock/shock interactions between bodies and wings

    Directory of Open Access Journals (Sweden)

    Gaoxiang XIANG

    2018-02-01

    Full Text Available This paper examines the Shock/Shock Interactions (SSI between the body and wing of aircraft in supersonic flows. The body is simplified to a flat wedge and the wing is assumed to be a sharp wing. The theoretical spatial dimension reduction method, which transforms the 3D problem into a 2D one, is used to analyze the SSI between the body and wing. The temperature and pressure behind the Mach stem induced by the wing and body are obtained, and the wave configurations in the corner are determined. Numerical validations are conducted by solving the inviscid Euler equations in 3D with a Non-oscillatory and Non-free-parameters Dissipative (NND finite difference scheme. Good agreements between the theoretical and numerical results are obtained. Additionally, the effects of the wedge angle and sweep angle on wave configurations and flow field are considered numerically and theoretically. The influences of wedge angle are significant, whereas the effects of sweep angle on wave configurations are negligible. This paper provides useful information for the design and thermal protection of aircraft in supersonic and hypersonic flows. Keywords: Body and wing, Flow field, Hypersonic flow, Shock/shock interaction, Wave configurations

  15. Analytical solutions of hypersonic type IV shock - shock interactions

    Science.gov (United States)

    Frame, Michael John

    An analytical model has been developed to predict the effects of a type IV shock interaction at high Mach numbers. This interaction occurs when an impinging oblique shock wave intersects the most normal portion of a detached bow shock. The flowfield which develops is complicated and contains an embedded jet of supersonic flow, which may be unsteady. The jet impinges on the blunt body surface causing very high pressure and heating loads. Understanding this type of interaction is vital to the designers of cowl lips and leading edges on air- breathing hypersonic vehicles. This analytical model represents the first known attempt at predicting the geometry of the interaction explicitly, without knowing beforehand the jet dimensions, including the length of the transmitted shock where the jet originates. The model uses a hyperbolic equation for the bow shock and by matching mass continuity, flow directions and pressure throughout the flowfield, a prediction of the interaction geometry can be derived. The model has been shown to agree well with the flowfield patterns and properties of experiments and CFD, but the prediction for where the peak pressure is located, and its value, can be significantly in error due to a lack of sophistication in the model of the jet fluid stagnation region. Therefore it is recommended that this region of the flowfield be modeled in more detail and more accurate experimental and CFD measurements be used for validation. However, the analytical model has been shown to be a fast and economic prediction tool, suitable for preliminary design, or for understanding the interactions effects, including the basic physics of the interaction, such as the jet unsteadiness. The model has been used to examine a wide parametric space of possible interactions, including different Mach number, impinging shock strength and location, and cylinder radius. It has also been used to examine the interaction on power-law shaped blunt bodies, a possible candidate for

  16. "Driverless" Shocks in the Interplanetary Medium

    Science.gov (United States)

    Gopalswamy, N.; Kaiser, M. L.; Lara, A.

    1999-01-01

    Many interplanetary shocks have been detected without an obvious driver behind them. These shocks have been thought to be either blast waves from solar flares or shocks due to sudden increase in solar wind speed caused by interactions between large scale open and closed field lines of the Sun. We investigated this problem using a set of interplanetary shock detected {\\it in situ} by the Wind space craft and tracing their solar origins using low frequency radio data obtained by the Wind/WAVES experiment. For each of these "driverless shocks" we could find a unique coronal mass ejections (CME) event observed by the SOHO (Solar and Heliospheric Observatory) coronagraphs. We also found that these CMEs were ejected at large angles from the Sun-Earth line. It appears that the "driverless shocks" are actually driver shocks, but the drivers were not intercepted by the spacecraft. We conclude that the interplanetary shocks are much more extended than the driving CMEs.

  17. Shock and Vibration. Volume 1, Issue 1

    National Research Council Canada - National Science Library

    Pilkey, Walter D

    1994-01-01

    ..., and earthquake engineering. Among the specific areas to be covered are vibration testing and control, vibration condition monitoring and diagnostics, shock hardenings, modal technology, shock testing, data acquisition, fluid...

  18. Initial ISEE magnetometer results: shock observation

    International Nuclear Information System (INIS)

    Russell, C.T.

    1979-01-01

    ISEE-1 and -2 magnetic field profiles across 6 terrestrial bow shock and one interplanetary shock are examined. The inteplanetary shock illustrates the behavior of a low Mach number shock. Three examples of low or moderate β, high Mach number, quasi-perpendicular shocks are examined. These did not have upstream waves, but rather had waves growing in the field gradient. Two examples of high β shocks showed little coherence in field variation even though the two vehicles were only a few hundred kilometers apart. The authors present the joint behavior of wave, particle and field data across some of these shocks to show some of the myriad of shock features whose behavior they are now beginning to investigate. (Auth.)

  19. Inferior vena cava obstruction and shock

    Directory of Open Access Journals (Sweden)

    Megri Mohammed

    2018-01-01

    Full Text Available Shock is one of the most challenging life-threatening conditions with high mortality and morbidity; the outcomes are highly dependent on the early detection and management of the condition. Septic shock is the most common type of shock in the Intensive Care Unit. While not as common as other subsets of shock, obstructive shock is a significant subtype due to well defined mechanical and pathological causes, including tension pneumothorax, massive pulmonary embolism, and cardiac tamponade. We are presenting a patient with obstructive shock due to inferior vena cava obstruction secondary to extensive deep venous thrombosis. Chance of survival from obstructive shock in our patient was small; however, there was complete and immediate recovery after treatment of the obstruction on recognizing the affected vessels. This case alerts the practicing intensivist and the emergency medicine physician to consider occlusion of the great vessels other than the pulmonary artery or aorta as causes of obstructive shock.

  20. Shock dynamics in layered periodic media

    KAUST Repository

    Ketcheson, David I.

    2012-01-01

    Solutions of constant-coeffcient nonlinear hyperbolic PDEs generically develop shocks, even if the initial data is smooth. Solutions of hyperbolic PDEs with variable coeffcients can behave very differently. We investigate formation and stability of shock waves in a one-dimensional periodic layered medium by a computational study of time-reversibility and entropy evolution. We find that periodic layered media tend to inhibit shock formation. For small initial conditions and large impedance variation, no shock formation is detected even after times much greater than the time of shock formation in a homogeneous medium. Furthermore, weak shocks are observed to be dynamically unstable in the sense that they do not lead to significant long-term entropy decay. We propose a characteristic condition for admissibility of shocks in heterogeneous media that generalizes the classical Lax entropy condition and accurately predicts the formation or absence of shocks in these media.

  1. Biological Agents

    Science.gov (United States)

    ... E-Tools Safety and Health Topics / Biological Agents Biological Agents This page requires that javascript be enabled ... 202) 693-2300 if additional assistance is required. Biological Agents Menu Overview In Focus: Ebola Frederick A. ...

  2. Converging cylindrical shocks in ideal magnetohydrodynamics

    International Nuclear Information System (INIS)

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ 0 /p 0 ) I/(2 π) where I is the current, μ 0 is the permeability, and p 0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field

  3. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  4. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, Ravi

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  5. Converging cylindrical shocks in ideal magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pullin, D. I. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States); Mostert, W.; Wheatley, V. [School of Mechanical and Mining Engineering, University of Queensland, Queensland 4072 (Australia); Samtaney, R. [Mechanical Engineering, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2014-09-15

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ{sub 0}/p{sub 0}) I/(2 π) where I is the current, μ{sub 0} is the permeability, and p{sub 0} is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The

  6. Entropy jump across an inviscid shock wave

    Science.gov (United States)

    Salas, Manuel D.; Iollo, Angelo

    1995-01-01

    The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.

  7. Collisionless Electrostatic Shock Modeling and Simulation

    Science.gov (United States)

    2016-10-21

    equations with piston -like boundary conditions gives a solution for the shock behavior. • Assumes cold upstream ions, therefore neglecting shock...temperature ratio (>10) – Wave Train Wavelength – Shock-Front Mach Number – Reflected Ion Beam Velocity Gathering Experiment Data – Double Plasma Device...experimental shock data. • Inconsistencies in published 1969 double -plasma device data hampered validation. Future Work: Extension to Moderately

  8. Shock waves in gas and plasma

    International Nuclear Information System (INIS)

    Niu, K.

    1996-01-01

    A shock wave is a discontinuous surface that connects supersonic flow with subsonic flow. After a shock wave, flow velocity is reduced, and pressure and temperature increase; entropy especially increases across a shock wave. Therefore, flow is in nonequilibrium, and irreversible processes occur inside the shock layer. The thickness of a shock wave in neutral gas is of the order of the mean free path of the fluid particle. A shock wave also appears in magnetized plasma. Provided that when the plasma flow is parallel to the magnetic field, a shock wave appears if the governing equation for velocity potential is in hyperbolic type in relation with the Mach number and the Alfven number. When the flow is perpendicular to the magnetic field, the Maxwell stress, in addition to the pressure, plays a role in the shock wave in plasma. When the plasma temperature is so high, as the plasma becomes collision-free, another type of shock wave appears. In a collision-free shock wave, gyromotions of electrons around the magnetic field lines cause the shock formation instead of collisions in a collision-dominant plasma or neutral gas. Regardless of a collision-dominant or collision-free shock wave, the fluid that passes through the shock wave is heated in addition to being compressed. In inertial confinement fusion, the fuel must be compressed. Really, implosion motion performs fuel compression. A shock wave, appearing in the process of implosion, compresses the fuel. The shock wave, however, heats the fuel more intensively, and it makes it difficult to compress the fuel further because high temperatures invite high pressure. Adiabatic compression of the fuel is the desired result during the implosion, without the formation of a shock wave. (Author)

  9. Electric shock and electrical fire specialty

    International Nuclear Information System (INIS)

    2011-02-01

    This book deals with electric shock and electrical fire, which is made up seven chapters. It describes of special measurement for electric shock and electrical fire. It mentions concretely about electrical fire analysis and precautionary measurement, electrical shock analysis cases, occurrence of static electricity and measurement, gas accident, analysis of equipment accident and precautionary measurement. The book is published to educate the measurement on electric shock and electrical fire by electrical safety technology education center in Korea Electrical Safety Corporation.

  10. Prenatal temperature shocks reduce cooperation

    NARCIS (Netherlands)

    Duchoslav, Jan

    2017-01-01

    Climate change has not only led to a sustained rise in mean global temperature over the past decades, but also increased the frequency of extreme weather events. This paper explores the effect of temperature shocks in utero on later-life taste for cooperation. Using historical climate data combined

  11. Shock Incarceration: Rehabilitation or Retribution?

    Science.gov (United States)

    MacKenzie, Doris Layton; And Others

    1989-01-01

    Reviews Louisiana's shock incarceration program used as alternative to standard prison incarceration. Program involves short period of imprisonment in a "boot camp" type atmosphere followed by three phases of intensive parole supervision. Examines the program in regard to its rehabilitative potential and compares program elements to…

  12. Shock Mounting for Heavy Machines

    Science.gov (United States)

    Thompson, A. R.

    1984-01-01

    Elastomeric bearings eliminate extraneous forces. Rocket thrust transmitted from motor to load cells via support that absorbs extraneous forces so they do not affect accuracy of thrust measurements. Adapter spoked cone fits over forward end of rocket motor. Shock mounting developed for rocket engines under test used as support for heavy machines, bridges, or towers.

  13. 2-Shock layered tuning campaign

    Science.gov (United States)

    Masse, Laurent; Dittrich, T.; Khan, S.; Kyrala, G.; Ma, T.; MacLaren, S.; Ralph, J.; Salmonson, J.; Tipton, R.; Los Alamos Natl Lab Team; Lawrence Livermore Natl Lab Team

    2016-10-01

    The 2-Shock platform has been developed to maintain shell sphericity throughout the compression phase of an indirect-drive target implosion and produce a stagnating hot spot in a quasi 1D-like manner. A sub-scale, 1700 _m outer diameter, and thick, 200 _m, uniformly Silicon doped, gas-filled plastic capsule is driven inside a nominal size 5750 _m diameter ignition hohlraum. The hohlraum fill is near vacuum to reduce back-scatter and improve laser/drive coupling. A two-shock pulse of about 1 MJ of laser energy drives the capsule. The thick capsule prevents ablation front feed-through to the imploded core. This platform has demonstrated its efficiency to tune a predictable and reproducible 1-D implosion with a nearly round shape. It has been shown that the high foot performance was dominated by the local defect growth due to the ablation front instability and by the hohlraum radiation asymmetries. The idea here is to take advantage of this 2-Shock platform to design a 1D-like layered implosion and eliminates the deleterious effects of radiation asymmetries and ablation front instability growth. We present the design work and our first experimental results of this near one-dimensional 2-Shock layered design. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  14. Interstellar turbulence and shock waves

    International Nuclear Information System (INIS)

    Bykov, A.M.

    1982-01-01

    Random deflections of shock fronts propagated through the turbulent interstellar medium can produce the strong electro-density fluctuations on scales l> or approx. =10 13 cm inferred from pulsar radio scintillations. The development of turbulence in the hot-phase ISM is discussed

  15. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    However, genuine nonlinearity is always present in an ideal gas. The conservation form of the equation (25) brings in shocks which cut off the growing part of the amplitUde as shown in. Figure 15. Acknowledgements. The author sincerely thanks the two referees whose valuable comments led to an improvement of the ...

  16. Model for Shock Wave Chaos

    KAUST Repository

    Kasimov, Aslan R.

    2013-03-08

    We propose the following model equation, ut+1/2(u2−uus)x=f(x,us) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, x<0, and the shock is located at x=0 for any t≥0. Here, us(t) is the shock state and the source term f is taken to mimic the chemical energy release in detonations. This equation retains the essential physics needed to reproduce many properties of detonations in gaseous reactive mixtures: steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

  17. EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AS ...

    African Journals Online (AJOL)

    Objective To evaluate extracorporeal shock wave lithotripsy (ESWL) as a monotherapy for urolithiasis in patients with solitary kidney and to determine the factors that may affect its results. Patients and Methods Using the Dornier MFL 5000 lithotriptor, 106 patients with solitary kidney (80 men and 26 women) were treated for ...

  18. Shock formation within sonoluminescence bubbles

    International Nuclear Information System (INIS)

    Vuong, V.Q.; Szeri, A.J.; Young, D.A.

    1999-01-01

    A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considered. It is found that, although at the main collapse the bubble wall does indeed launch an inwardly-traveling compression wave, and although the subsequent reflection of the wave at the bubble center produces a very rapid temperature peak, the wave is prevented from steepening into a sharp shock by an adverse gradient in the sound speed caused by heat transfer. It is shown that the mathematical characteristics of the flow can be prevented from accumulating into a shock front by this adverse sound speed gradient. A range of results is presented for a variety of bubble ambient radii and sound field amplitudes suggested by experiments. The time scale of the peak temperature in the bubble is set by the dynamics of the compression wave: this is typically in the range 100 - 300 ps (FWHM) in concert with recent measurements of the sonoluminescence pulse width. copyright 1999 American Institute of Physics

  19. Model for Shock Wave Chaos

    KAUST Repository

    Kasimov, Aslan R.; Faria, Luiz; Rosales, Rodolfo R.

    2013-01-01

    : steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation

  20. Studying shocks in model astrophysical flows

    International Nuclear Information System (INIS)

    Chakrabarti, S.K.

    1989-01-01

    We briefly discuss some properties of the shocks in the existing models for quasi two-dimensional astrophysical flows. All of these models which allow the study of shock analytically have some unphysical characteristics due to inherent assumptions made. We propose a hybrid model for a thin flow which has fewer unpleasant features and is suitable for the study of shocks. (author). 5 refs

  1. Shock waves in relativistic nuclear matter, I

    International Nuclear Information System (INIS)

    Gleeson, A.M.; Raha, S.

    1979-02-01

    The relativistic Rankine-Hugoniot relations are developed for a 3-dimensional plane shock and a 3-dimensional oblique shock. Using these discontinuity relations together with various equations of state for nuclear matter, the temperatures and the compressibilities attainable by shock compression for a wide range of laboratory kinetic energy of the projectile are calculated. 12 references

  2. The microphysics of collisionless shock waves

    DEFF Research Database (Denmark)

    Marcowith, Alexandre; Bret, Antoine; Bykov, Andrei

    2016-01-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active ga...

  3. Permeability enhancement by shock cooling

    Science.gov (United States)

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

    2015-04-01

    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  4. Heat shock suppresses mating and sperm transfer in the rice leaf folder Cnaphalocrocis medinalis.

    Science.gov (United States)

    Liao, H J; Qian, Q; Liu, X D

    2014-06-01

    Temperature is a key environmental factor in determining the population size of Cnaphalocrocis medinalis in summer. High temperatures inhibit survival, development and fecundity of this insect. However, biological responses of female and male adults to heat shock, and physiological mechanism of high temperature suppressing population development are still ambiguous. We experimentally tested the impact of heat shock (5 h day-1) on biological traits, spermatogenesis and sperm transfer of adults of C. medinalis. The result showed that heat exposure to 39 and 40 °C for 5 h reduced longevity and copulation frequency of adults, and hatchability of eggs. Immediate survival rate of males was lower than that of females after 3 days of exposure to 41 °C. The oviposition period, copulation frequency, fecundity of adults and hatchability of eggs were significantly lower when male adults were exposed to 40 or 41 °C for 3 days. Heat shock decreased frequency and success rate of mating when males were exposed, and it also resulted in postponement of mating behaviour and prolongation of mating duration as both the female and male adults were exposed. Heat shock did not affect spermatogenesis, but significantly inhibited sperms maturation. Moreover, males could not ejaculate sperm into females during copulation when these male moths received heat shock. Heat shock remarkably suppressed mating behaviour and sperm transfer, which led to a dramatic decline of rice leaf folder populations.

  5. Inappropriate shocks in the subcutaneous ICD

    DEFF Research Database (Denmark)

    Olde Nordkamp, Louise R A; Brouwer, Tom F; Barr, Craig

    2015-01-01

    shocks have been reported. METHODS: We analyzed the incidence, predictors and management of inappropriate shocks in the EFFORTLESS S-ICD Registry, which collects S-ICD implantation information and follow-up data from clinical centers in Europe and New Zealand. RESULTS: During a follow-up of 21 ± 13...... xyphoid to V6) reduced the risk. Reprogramming or optimization of SVT treatment after the first clinical event of inappropriate shock was successful in preventing further inappropriate shocks for cardiac oversensing and SVT events. CONCLUSIONS: Inappropriate shocks, mainly due to cardiac oversensing...

  6. Cold shock to aquatic organisms: guidance for power-plant siting, design, and operation

    International Nuclear Information System (INIS)

    Coutant, C.C.

    1977-01-01

    Problems of cold-shock damages to aquatic organisms have arisen at some condenser cooling-water discharges of thermal power stations when the warm-water releases have suddenly terminated. The basis for such damage lies in the exposure of resident organisms to a rapid decrease in temperature and a sustained exposure to low temperature that induces abnormal behavioral or physiological performance and often leads to death. Although some spectacular fish kills from cold shock have occurred, the present knowledge of the hydraulic and biological processes involved can provide guidance for the siting, design, and operation of power-plant cooling systems to minimize the likelihood of significant cold-shock effects. Preventing cold-shock damages is one consideration in minimizing overall environmental impacts of power-plant cooling and in balancing plant costs with environmental benefits

  7. Perpendicular relativistic shocks in magnetized pair plasma

    Science.gov (United States)

    Plotnikov, Illya; Grassi, Anna; Grech, Mickael

    2018-04-01

    Perpendicular relativistic (γ0 = 10) shocks in magnetized pair plasmas are investigated using two dimensional Particle-in-Cell simulations. A systematic survey, from unmagnetized to strongly magnetized shocks, is presented accurately capturing the transition from Weibel-mediated to magnetic-reflection-shaped shocks. This transition is found to occur for upstream flow magnetizations 10-3 10-2, it leaves place to a purely electromagnetic precursor following from the strong emission of electromagnetic waves at the shock front. Particle acceleration is found to be efficient in weakly magnetized perpendicular shocks in agreement with previous works, and is fully suppressed for σ > 10-2. Diffusive Shock Acceleration is observed only in weakly magnetized shocks, while a dominant contribution of Shock Drift Acceleration is evidenced at intermediate magnetizations. The spatial diffusion coefficients are extracted from the simulations allowing for a deeper insight into the self-consistent particle kinematics and scale with the square of the particle energy in weakly magnetized shocks. These results have implications for particle acceleration in the internal shocks of AGN jets and in the termination shocks of Pulsar Wind Nebulae.

  8. Initial conditions of radiative shock experiments

    International Nuclear Information System (INIS)

    Kuranz, C. C.; Drake, R. P.; Krauland, C. M.; Marion, D. C.; Grosskopf, M. J.; Rutter, E.; Torralva, B.; Holloway, J. P.; Bingham, D.; Goh, J.; Boehly, T. R.; Sorce, A. T.

    2013-01-01

    We performed experiments at the Omega Laser Facility to characterize the initial, laser-driven state of a radiative shock experiment. These experiments aimed to measure the shock breakout time from a thin, laser-irradiated Be disk. The data are then used to inform a range of valid model parameters, such as electron flux limiter and polytropic γ, used when simulating radiative shock experiments using radiation hydrodynamics codes. The characterization experiment and the radiative shock experiment use a laser irradiance of ∼7 × 10 14 W cm −2 to launch a shock in the Be disk. A velocity interferometer and a streaked optical pyrometer were used to infer the amount of time for the shock to move through the Be disk. The experimental results were compared with simulation results from the Hyades code, which can be used to model the initial conditions of a radiative shock system using the CRASH code

  9. Exploratory laser-driven shock wave studies

    International Nuclear Information System (INIS)

    Solem, J.C.; Veeser, L.R.

    1977-11-01

    We show the results of a feasibility study for investigating shock structure and for measuring equation-of-state parameters using high-energy, short-pulse lasers. We discuss the temporal and spatial structure of the luminosity from laser-driven shock unloading in aluminum foils. We demonstrate that shock velocity can be measured by observing the time interval between shock emergence across two thicknesses and show data for shocks of 1.3 and 2.1 Mbar. The fact that we observe shock fronts cleanly breaking through steps as small as 3 μm indicates that the shock front thickness is very small in the few megabar region; this is the first experimental verification that these fronts are not more than a few micrometers thick. We present approximate measurements of free-surface velocity. Finally, we speculate on the use of these techniques to obtain detailed equation-of-state data

  10. Shock-induced chemistry in organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve [Los Alamos National Laboratory; Engelke, Ray [Los Alamos National Laboratory; Manner, Virginia [Los Alamos National Laboratory; Chellappa, Raja [Los Alamos National Laboratory; Yoo, Choong - Shik [WASHINGTON STATE UNIV

    2011-01-20

    The combined 'extreme' environments of high pressure, temperature, and strain rates, encountered under shock loading, offer enormous potential for the discovery of new paradigms in chemical reactivity not possible under more benign conditions. All organic materials are expected to react under these conditions, yet we currently understand very little about the first bond-breaking steps behind the shock front, such as in the shock initiation of explosives, or shock-induced reactivity of other relevant materials. Here, I will present recent experimental results of shock-induced chemistry in a variety of organic materials under sustained shock conditions. A comparison between the reactivity of different structures is given, and a perspective on the kinetics of reaction completion under shock drives.

  11. Experimental methods of shock wave research

    CERN Document Server

    Seiler, Friedrich

    2016-01-01

    This comprehensive and carefully edited volume presents a variety of experimental methods used in Shock Waves research. In 14 self contained chapters this 9th volume of the “Shock Wave Science and Technology Reference Library” presents the experimental methods used in Shock Tubes, Shock Tunnels and Expansion Tubes facilities. Also described is their set-up and operation. The uses of an arc heated wind tunnel and a gun tunnel are also contained in this volume. Whenever possible, in addition to the technical description some typical scientific results obtained using such facilities are described. Additionally, this authoritative book includes techniques for measuring physical properties of blast waves and laser generated shock waves. Information about active shock wave laboratories at different locations around the world that are not described in the chapters herein is given in the Appendix, making this book useful for every researcher involved in shock/blast wave phenomena.

  12. Motion of shocks through interplanetary streams

    International Nuclear Information System (INIS)

    Burlaga, L.F.; Scudder, J.D.

    1975-01-01

    A model for the motion of flare-generated shocks through interplanetary streams is presented, illustrating the effects of a stream-shock interaction on the shock strength and geometry. It is a gas dynamic calculation based on Whitham's method and on an empirical approximation for the relevant characteristics of streams. The results show that the Mach number of a shock can decrease appreciably to near unity in the interaction region ahead of streams and that the interaction of a spherically symmetric shock with a spiral-shaped corotating stream can cause significant distortions of the initial shock front geometry. The geometry of the February 15--16, 1967, shock discussed by Lepping and Chao (1972) is qualitatively explained by this model

  13. Do oil shocks predict economic policy uncertainty?

    Science.gov (United States)

    Rehman, Mobeen Ur

    2018-05-01

    Oil price fluctuations have influential role in global economic policies for developed as well as emerging countries. I investigate the role of international oil prices disintegrated into structural (i) oil supply shock, (ii) aggregate demand shock and (iii) oil market specific demand shocks, based on the work of Kilian (2009) using structural VAR framework on economic policies uncertainty of sampled markets. Economic policy uncertainty, due to its non-linear behavior is modeled in a regime switching framework with disintegrated structural oil shocks. Our results highlight that Indian, Spain and Japanese economic policy uncertainty responds to the global oil price shocks, however aggregate demand shocks fail to induce any change. Oil specific demand shocks are significant only for China and India in high volatility state.

  14. Shock Wave Dynamics in Weakly Ionized Plasmas

    Science.gov (United States)

    Johnson, Joseph A., III

    1999-01-01

    An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.

  15. Study on Reflected Shock Wave/Boundary Layer Interaction in a Shock Tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Wook; Kim, Tae Ho; Kim, Heuy Dong [Andong Nat’l Univ., Andong (Korea, Republic of)

    2017-07-15

    The interaction between a shock wave and a boundary layer causes boundary layer separation, shock train, and in some cases, strong unsteadiness in the flow field. Such a situation is also observed in a shock tube, where the reflected shock wave interacts with the unsteady boundary layer. However, only a few studies have been conducted to investigate the shock train phenomenon in a shock tube. In the present study, numerical studies were conducted using the two-dimensional axisymmetric domain of a shock tube, and compressible Navier-Stokes equations were solved to clarify the flow characteristics of shock train phenomenon inside a shock tube. A detailed wave diagram was developed based on the present computational results, which were validated with existing experimental data.

  16. Insight into magnetorheological shock absorbers

    CERN Document Server

    Gołdasz, Janusz

    2015-01-01

    This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

  17. Magnetohydrodynamic shocks in molecular clouds

    International Nuclear Information System (INIS)

    Chernoff, D.F.

    1985-01-01

    Part one develops the mathematical and physical theory of one-dimensional, time-independent subalfvenic flow in partially ionized gas with magnetic fields, for application to shocks in molecular clouds. Unlike normal gas-dynamic shocks, the neutral flow may be continuous and cool if the gas radiates efficiently and does not self-ionize. Analytic solutions are given in the limit that the neutral gas is either adiabatic or isothermal (cold). Numerical techniques are developed and applied to find the neutral flow under general circumstances. Part two extends the theory and results of part one in three ways: (1) to faster, superalfvenic flow, (2) to complex gases containing heavy charged particles (grains) in addition to ions, containing heavy charged particles (grains) in addition to ions, electrons and neutrals, and (3) to the entire range in (Omega tau), the ratio of charged particle damping time to gyroperiod, expected in gas flows in molecular clouds

  18. MHD shocks in the ISM

    Science.gov (United States)

    Chernoff, D. F.; Hollenbach, David J.; Mckee, Christopher F.

    1990-01-01

    Researchers survey shock solutions of a partially ionized gas with a magnetic field. The gas is modeled by interacting neutral, ion, electron and charged grain components. They employ a small neutral-ion chemical network to follow the dissociation and ionization of the major species. Cooling by molecular hydrogen (rotational, vibrational and dissociation), grains and dipole molecules is included. There are three basic types of solutions (C, C asterisk, and J) and some more complicated flows involving combinations of the basic types. The initial preshock conditions cover hydrogen nuclei densities of 1 less than n less than 10(exp 10) cm(-3) and shock velocities of 5 less than v(sub s) less than 60 km/s. The magnetic field is varied over 5 decades and the sensitivity of the results to grain parameters, UV and cosmic ray fluxes is ascertained. The parameter space is quite complicated, but there exist some simple divisions. When the initial ionization fraction is small (chi sub i less than 10(-5)), there is a sharp transition between fully C solutions at low velocity and strong J solutions at high velocity. When the initial ionization fraction is larger, C asterisk and/or very weak J shocks are present at low velocities in addition to the C solutions. The flow again changes to strong J shocks at high velocities. When the ionization fraction is large and the flow is only slightly greater than the bulk Alfven velocity, there is a complicated mixture of C, C asterisk and J solutions.

  19. Measuring resilience to energy shocks

    OpenAIRE

    Molyneaux, Lynette; Brown, Colin; Foster, John; Wagner, Liam

    2015-01-01

    Measuring energy security or resilience in energy is, in the main, confined to indicators which are used for comparative purposes or to show trends rather than provide empirical evidence of resilience to unpredicted crises. In this paper, the electricity systems of the individual states within the United States of America are analysed for their response to the 1973-1982 and the 2003-2012 oil price shocks. Empirical evidence is sought for elements which are present in systems that experience r...

  20. Coronal mass ejection shock fronts containing the two types of intermediate shocks

    International Nuclear Information System (INIS)

    Steinolfson, R.S.; Hundhausen, A.J.

    1990-01-01

    Numerical solutions of the time-dependent, magnetohydrodynamic (MHD) equations in two dimensions are used to demonstrate the formation of both types of intermediate shocks in a single shock front for physical conditions that are an idealization of those expected to occur in some observed coronal mass ejections. The key to producing such a shock configuration in the simulations is the use of an initial atmosphere containing a magnetic field representative of that in a coronal streamer with open field lines overlying a region of closed field lines. Previous attempts using just open field lines (perpendicular to the surface) produced shock configurations containing just one of the two intermediate shock types. A schematic of such a shock front containing both intermediate shock types has been constructed previously based solely on the known properties of MHD shocks from the Rankine-Hugoniot equations and specific requirements placed on the shock solution at points along the front where the shock normal and upstream magnetic field are aligned. The shock front also contains, at various locations along the front, a hydrodynamic (nonmagnetic) shock, a switch-on shock, and a fast shock in addition to the intermediate shocks. This particular configuration occurs when the shock front speed exceeds the upstream (preshock) intermediate wave speed but is less than a critical speed defined in the paper (equation 1) along at least some portion of the shock front. A distinctive feature of the front is that it is concave upward (away from the surface) near the region where the field in the preshock plasma is normal to the front of near the central portion of the shock front

  1. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  2. Particle Acceleration in Two Converging Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Na; Shan, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Giacalone, Joe [Lunar and Planetary Laboratory, University of Arizona, Tucson AZ 85721 (United States); Yan, Yihua [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing 100012 (China); Ding, Mingde, E-mail: wangxin@xao.ac.cn [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education, Nanjing 210093 (China)

    2017-06-20

    Observations by spacecraft such as ACE , STEREO , and others show that there are proton spectral “breaks” with energy E {sub br} at 1–10 MeV in some large CME-driven shocks. Generally, a single shock with the diffusive acceleration mechanism would not predict the “broken” energy spectrum. The present paper focuses on two converging shocks to identify this energy spectral feature. In this case, the converging shocks comprise one forward CME-driven shock on 2006 December 13 and another backward Earth bow shock. We simulate the detailed particle acceleration processes in the region of the converging shocks using the Monte Carlo method. As a result, we not only obtain an extended energy spectrum with an energy “tail” up to a few 10 MeV higher than that in previous single shock model, but also we find an energy spectral “break” occurring on ∼5.5 MeV. The predicted energy spectral shape is consistent with observations from multiple spacecraft. The spectral “break,” then, in this case is caused by the interaction between the CME shock and Earth’s bow shock, and otherwise would not be present if Earth were not in the path of the CME.

  3. Simulation of turbulent flows containing strong shocks

    International Nuclear Information System (INIS)

    Fryxell, Bruce; Menon, Suresh

    2008-01-01

    Simulation of turbulent flows with strong shocks is a computationally challenging problem. The requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphysical rate of decay of the turbulence. This paper discusses a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, whereas the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems. Preliminary results for a realistic application involving detonation in gas-particle flows will also be presented.

  4. Electron velocity distributions near collisionless shocks

    International Nuclear Information System (INIS)

    Feldman, W.C.

    1984-01-01

    Recent studies of the amount of electron heating and of the shapes of electron velocity distributions across shocks near the earth are reviewed. It is found that electron heating increases with increasing shock strength but is always less than the ion heating. The scale length of electron heating is also less than that for the ions. Electron velocity distributions show characteristic shapes which depend on the strength of the shocks. At the weaker shocks, electron heating is mostly perpendicular to the ambient magnetic field, bar B, and results in Gaussian-shaped velocity distributions at low-to-moderate energies. At the stronger shocks, parallel heating predominates resulting in flat-topped velocity distributions. A reasonable interpretation of these results indicates that at the weaker shocks electron heating is dominated by a tendency toward conservation of the magnetic moment. At the stronger fast-mode shocks, this heating is thought to be dominated by an acceleration parallel to bar B produced by the macroscopic shock electric field followed by beam driven plasma instabilities. Some contribution to the heating at the stronger shocks from conservation of the magnetic moment and cross-field current-driven instabilities cannot be ruled out. Although the heating at slow-mode shocks is also dominated by instabilities driven by magnetic field-aligned electron beams, their acceleration mechanism is not yet established

  5. Modern Biology

    OpenAIRE

    ALEKSIC, Branko

    2014-01-01

    The purpose of this course is to learn the philosophy, principles, and techniques of modern biology. The course is particularly designed for those who have not learned biology previously or whose major is other than biology, and who may think that they do not need to know any biology at all. The topics are covered in a rather general, overview manner, but certain level of diligence in grasping concepts and memorizing the terminology is expected.

  6. Computer simulations of collisionless shock waves

    International Nuclear Information System (INIS)

    Leroy, M.M.

    1984-01-01

    A review of the contributions of particle computer simulations to the understanding of the physics of magnetic shock waves in collisionless plasmas is presented. The emphasis is on the relation between the computer simulation results, spacecraft observations of shocks in space, and related theories, rather than on technical aspects of the numerics. It is shown that much has been learned from the comparison of ISEE spacecraft observations of the terrestrial bow shock and particle computer simulations concerning the quasi-perpendicular, supercritical shock (ion scale structure, ion reflection mechanism and ultimate dissipation processes). Particle computer simulations have also had an appreciable prospective role in the investigation of the physics of quasi-parallel shocks, about which still little is known observationally. Moreover, these numerical techniques have helped to clarify the process of suprathermal ion rejection by the shock into the foreshock, and the subsequent evolution of the ions in the foreshock. 95 references

  7. Molecular dynamics simulation of laser shock phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Ichirou [Japan Atomic Energy Research Inst., Kansai Research Establishment, Advanced Photon Research Center, Neyagawa, Osaka (Japan).

    2001-10-01

    Recently, ultrashort-pulse lasers with high peak power have been developed, and their application to materials processing is expected as a tool of precision microfabrication. When a high power laser irradiates, a shock wave propagates into the material and dislocations are generated. In this paper, laser shock phenomena of the metal were analyzed using the modified molecular dynamics method, which has been developed by Ohmura and Fukumoto. The main results obtained are summarized as follows: (1) The shock wave induced by the Gaussian beam irradiation propagates radially from the surface to the interior. (2) A lot of dislocations are generated at the solid-liquid interface by the propagation of a shock wave. (3) Some dislocations are moved instantaneously with the velocity of the longitudinal wave when the shock wave passes, and their velocity is not larger than the transverse velocity after the shock wave has passed. (author)

  8. Entropy Generation Across Earth's Bow Shock

    Science.gov (United States)

    Parks, George K.; McCarthy, Michael; Fu, Suiyan; Lee E. s; Cao, Jinbin; Goldstein, Melvyn L.; Canu, Patrick; Dandouras, Iannis S.; Reme, Henri; Fazakerley, Andrew; hide

    2011-01-01

    Earth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.

  9. Remote shock sensing and notification system

    Science.gov (United States)

    Muralidharan, Govindarajan; Britton, Charles L.; Pearce, James; Jagadish, Usha; Sikka, Vinod K.

    2008-11-11

    A low-power shock sensing system includes at least one shock sensor physically coupled to a chemical storage tank to be monitored for impacts, and an RF transmitter which is in a low-power idle state in the absence of a triggering signal. The system includes interference circuitry including or activated by the shock sensor, wherein an output of the interface circuitry is coupled to an input of the RF transmitter. The interface circuitry triggers the RF transmitting with the triggering signal to transmit an alarm message to at least one remote location when the sensor senses a shock greater than a predetermined threshold. In one embodiment the shock sensor is a shock switch which provides an open and a closed state, the open state being a low power idle state.

  10. Role of echocardiography in reducing shock reversal time in pediatric septic shock: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ahmed A. EL‐Nawawy

    2018-01-01

    Conclusion: Serial echocardiography provided crucial data for early recognition of septic myocardial dysfunction and hypovolemia that was not apparent on clinical assessment, allowing a timely management and resulting in shock reversal time reduction among children with septic shock.

  11. The earth's foreshock, bow shock, and magnetosheath

    Science.gov (United States)

    Onsager, T. G.; Thomsen, M. F.

    1991-01-01

    Studies directly pertaining to the earth's foreshock, bow shock, and magnetosheath are reviewed, and some comparisons are made with data on other planets. Topics considered in detail include the electron foreshock, the ion foreshock, the quasi-parallel shock, the quasi-perpendicular shock, and the magnetosheath. Information discussed spans a broad range of disciplines, from large-scale macroscopic plasma phenomena to small-scale microphysical interactions.

  12. The earth's foreshock, bow shock, and magnetosheath

    International Nuclear Information System (INIS)

    Onsager, T.G.; Thomsen, M.F.

    1991-01-01

    Studies directly pertaining to the earth's foreshock, bow shock, and magnetosheath are reviewed, and some comparisons are made with data on other planets. Topics considered in detail include the electron foreshock, the ion foreshock, the quasi-parallel shock, the quasi-perpendicular shock, and the magnetosheath. Information discussed spans a broad range of disciplines, from large-scale macroscopic plasma phenomena to small-scale microphysical interactions. 184 refs

  13. Nonequilibrium chemistry in shocked molecular clouds

    International Nuclear Information System (INIS)

    Iglesias, E.R.; Silk, J.

    1978-01-01

    The gas phase chemistry is studied behind a 10 km s -1 shock propagating into a dense molecular cloud. Our principal conclusions are that the concentrations of certain molecules (CO, NH 3 , HCN, N 2 ) are unperturbed by the shock; other molecules (H 2 CO, CN, HCO + ) are greatly decreased in abundance; and substantial amounts of H 2 O, HCO, and CH 4 are produced. Approximately 10 6 yr (independent of the density) must elapse after shock passage before chemical equilibrium is attained

  14. Reaction effects in diffusive shock acceleration

    International Nuclear Information System (INIS)

    Drury, L.Oc.

    1984-01-01

    The effects of the reaction of accelerated particles back on the shock wave in the diffusive-shock-acceleration model of cosmic-ray generation are investigated theoretically. Effects examined include changes in the shock structure, modifications of the input and output spectra, scattering effects, and possible instabilities in the small-scale structure. It is pointed out that the latter two effects are applicable to any spatially localized acceleration mechanism. 14 references

  15. PIV tracer behavior on propagating shock fronts

    International Nuclear Information System (INIS)

    Glazyrin, Fyodor N; Mursenkova, Irina V; Znamenskaya, Irina A

    2016-01-01

    The present work was aimed at the quantitative particle image velocimetry (PIV) measurement of a velocity field near the front of a propagating shock wave and the study of the dynamics of liquid tracers crossing the shock front. For this goal, a shock tube with a rectangular cross-section (48  ×  24 mm) was used. The flat shock wave with Mach numbers M  =  1.4–2.0 propagating inside the tube channel was studied as well as an expanding shock wave propagating outside the channel with M  =  1.2–1.8 at its main axis. The PIV imaging of the shock fronts was carried out with an aerosol of dioctyl sebacate (DEHS) as tracer particles. The pressures of the gas in front of the shock waves studied ranged from 0.013 Mpa to 0.1 MPa in the series of experiments. The processed PIV data, compared to the 1D normal shock theory, yielded consistent values of wake velocity immediately behind the plain shock wave. Special attention was paid to the blurring of the velocity jump on the shock front due to the inertial particle lag and peculiarities of the PIV technique. A numerical algorithm was developed for analysis and correction of the PIV data on the shock fronts, based on equations of particle-flow interaction. By application of this algorithm, the effective particle diameter of the DEHS aerosol tracers was estimated as 1.03  ±  0.12 μm. A number of different formulations for particle drag were tested with this algorithm, with varying success. The results show consistency with previously reported experimental data obtained for cases of stationary shock waves. (paper)

  16. Viscoelastic shock wave in ballistic gelatin behind soft body armor.

    Science.gov (United States)

    Liu, Li; Fan, Yurun; Li, Wei

    2014-06-01

    Ballistic gelatins are widely used as a surrogate of biological tissue in blunt trauma tests. Non-penetration impact tests of handgun bullets on the 10wt% ballistic gelatin block behind soft armor were carried out in which a high-speed camera recorded the crater׳s movement and pressure sensors imbedded in the gelatin block recorded the pressure waves at different locations. The observed shock wave attenuation indicates the necessity of considering the gelatin׳s viscoelasticity. A three-element viscoelastic constitutive model was adopted, in which the relevant parameters were obtained via fitting the damping free oscillations at the beginning of the creep-mode of rheological measurement, and by examining the data of published split Hopkinson pressure bar (SHPB) experiments. The viscoelastic model is determined by a retardation time of 5.5×10(-5)s for high oscillation frequencies and a stress relaxation time of 2.0-4.5×10(-7)s for shock wave attenuation. Using the characteristic-line method and the spherical wave assumption, the propagation of impact pressure wave front and the subsequent unloading profile can be simulated using the experimental velocity boundary condition. The established viscoelastic model considerably improves the prediction of shock wave attenuation in the ballistic gelatin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Mathematical biology

    CERN Document Server

    Murray, James D

    1993-01-01

    The book is a textbook (with many exercises) giving an in-depth account of the practical use of mathematical modelling in the biomedical sciences. The mathematical level required is generally not high and the emphasis is on what is required to solve the real biological problem. The subject matter is drawn, e.g. from population biology, reaction kinetics, biological oscillators and switches, Belousov-Zhabotinskii reaction, reaction-diffusion theory, biological wave phenomena, central pattern generators, neural models, spread of epidemics, mechanochemical theory of biological pattern formation and importance in evolution. Most of the models are based on real biological problems and the predictions and explanations offered as a direct result of mathematical analysis of the models are important aspects of the book. The aim is to provide a thorough training in practical mathematical biology and to show how exciting and novel mathematical challenges arise from a genuine interdisciplinary involvement with the biosci...

  18. Condensed matter at high shock pressures

    International Nuclear Information System (INIS)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-01-01

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N 2 , CO, SiO 2 -aerogel, H 2 O, and C 6 H 6 . The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab

  19. Radio emission from coronal and interplanetary shocks

    International Nuclear Information System (INIS)

    Cane, H.V.

    1987-01-01

    Observational data on coronal and interplanetary (IP) type II burst events associated with shock-wave propagation are reviewed, with a focus on the past and potential future contributions of space-based observatories. The evidence presented by Cane (1983 and 1984) in support of the hypothesis that the coronal (metric) and IP (kilometric) bursts are due to different shocks is summarized, and the fast-drift kilometric events seen at the same time as metric type II bursts (and designated shock-accelerated or shock-associated events) are characterized. The need for further observations at 0.5-20 MHz is indicated. 20 references

  20. Advanced and Exploratory Shock Sensing Mechanisms.

    Energy Technology Data Exchange (ETDEWEB)

    Nelsen, Nicholas H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kolb, James D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kulkarni, Akshay G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorscher, Zachary [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Habing, Clayton D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mathis, Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Beller, Zachary J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Mechanical component response to shock environments must be predictable in order to ensure reliability and safety. Whether the shock input results from accidental drops during transportation to projectile impact scenarios, the system must irreversibly transition into a safe state that is incapable of triggering the component . With this critical need in mind, the 2017 Nuclear Weapons Summer Product Realization Institute (NW SPRINT) program objective sought the design of a passive shock failsafe with emphasis on additively manufactured (AM) components. Team Advanced and Exploratory (A&E) responded to the challenge by designing and delivering multiple passive shock sensing mech anisms that activate within a prescribed mechanical shock threshold. These AM failsafe designs were tuned and validated using analytical and computational techniques including the shock response spectrum (SRS) and finite element analysis (FEA). After rapid prototyping, the devices experienced physical shock tests conducted on Sandia drop tables to experimentally verify performance. Keywords: Additive manufacturing, dynamic system, failsafe, finite element analysis, mechanical shock, NW SPRINT, shock respon se spectrum

  1. Irreversible thermodynamics of overdriven shocks in solids

    International Nuclear Information System (INIS)

    Wallace, D.C.

    1981-01-01

    An isotropic solid capable of transporting heat and of undergoing dissipative plastic flow, is treated. The shock is assumed to be a steady wave, and any phase changes or macroscopic inhomogeneities which might be induced by the shock are neglected. Under these conditions it is established that for an overdriven shock, no solution is possible without heat transport, and when the heat transport is governed by the steady conduction equation, no solution is possible without plastic dissipation as well. Upper and lower bounds are established for the thermodynamic variables, namely the shear stress, temperature, entropy, plastic strain, and heat flux, as functions of compression through the shock

  2. The source of real and nominal exchange rate fluctuations in Thailand: Real shock or nominal shock

    OpenAIRE

    Le Thanh, Binh

    2015-01-01

    This paper examines the source of exchange rate fluctuations in Thailand. We employed a structural vector auto-regression (SVAR) model with the long-run neutrality restriction of Blanchard and Quah (1989) to investigate the changes in real and nominal exchange rates from 1994 to 2015. In this paper, we assume that there are two types of shocks which related to exchange rate movements: real shocks and nominal shocks. The empirical analysis indicates that real shocks are the fundamental compon...

  3. Role of heat shock protein 70 in innate alloimmunity

    Directory of Open Access Journals (Sweden)

    Walter G. eLand

    2012-01-01

    Full Text Available This article briefly describes our own experience with the proven demonstration of heat shock protein 70 in reperfused renal allografts from brain-deaddonors and reflects about its potential role as a typical damage-associated molecular pattern (DAMP in the setting of innate alloimmunity. In fact, our group was able to demonstrate a dramatic up-regulation of heat shock protein 70 expression after postischemic reperfusion of renal allografts. Of note, up-regulation of this stress protein expression, although to a lesser extent, was already observed after cold storage of the organ indicating that this molecule is already induced in the stressed organism of a brain-dead donor. However, whether or not the dramatic up-regulation of heat shock protein 70 expression contributes to mounting an innate alloimmune response cannot be judged in view of these clinical findings.Nevertheless, heat shock protein 70, since generated in association with postischemic reperfusion-induced allograft injury, can be called a typical DAMP - as can everymolecule be termed a DAMP that is generated in associationwith any stressful tissue injury regardless of its final positive or negative regulatory function within the innate immune response elicited by it.In fact, as we discuss in this article, the context-dependent, even contradistinctive activities of heat shock protein 70 reflect the biological phenomenon that, throughout evolution, mammals have developed an elaborate network of positive and negative regulatory mechanisms, which provide balance between defensive and protective measures against unwarranted destruction of the host. In this sense, up-regulated expression of heat shock protein 70 in an injured allograft might reflect a pure protective response against the severe oxidative injury of a reperfused donor organ. On the other hand, up-regulated expression of this stress protein in an injured allograft might reflect a(futile attempt of the innate immune system to

  4. Model for shock wave chaos.

    Science.gov (United States)

    Kasimov, Aslan R; Faria, Luiz M; Rosales, Rodolfo R

    2013-03-08

    We propose the following model equation, u(t) + 1/2(u(2)-uu(s))x = f(x,u(s)) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, xorder partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

  5. Adaptive inertial shock-absorber

    International Nuclear Information System (INIS)

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-01-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated. (paper)

  6. Converging shocks in elastic-plastic solids.

    Science.gov (United States)

    Ortega, A López; Lombardini, M; Hill, D J

    2011-11-01

    We present an approximate description of the behavior of an elastic-plastic material processed by a cylindrically or spherically symmetric converging shock, following Whitham's shock dynamics theory. Originally applied with success to various gas dynamics problems, this theory is presently derived for solid media, in both elastic and plastic regimes. The exact solutions of the shock dynamics equations obtained reproduce well the results obtained by high-resolution numerical simulations. The examined constitutive laws share a compressible neo-Hookean structure for the internal energy e=e(s)(I(1))+e(h)(ρ,ς), where e(s) accounts for shear through the first invariant of the Cauchy-Green tensor, and e(h) represents the hydrostatic contribution as a function of the density ρ and entropy ς. In the strong-shock limit, reached as the shock approaches the axis or origin r=0, we show that compression effects are dominant over shear deformations. For an isothermal constitutive law, i.e., e(h)=e(h)(ρ), with a power-law dependence e(h) is proportional to ρ(α), shock dynamics predicts that for a converging shock located at r=R(t) at time t, the Mach number increases as M is proportional to [log(1/R)](α), independently of the space index s, where s=2 in cylindrical geometry and 3 in spherical geometry. An alternative isothermal constitutive law with p(ρ) of the arctanh type, which enforces a finite density in the strong-shock limit, leads to M is proportional to R(-(s-1)) for strong shocks. A nonisothermal constitutive law, whose hydrostatic part e(h) is that of an ideal gas, is also tested, recovering the strong-shock limit M is proportional to R(-(s-1)/n(γ)) originally derived by Whitham for perfect gases, where γ is inherently related to the maximum compression ratio that the material can reach, (γ+1)/(γ-1). From these strong-shock limits, we also estimate analytically the density, radial velocity, pressure, and sound speed immediately behind the shock. While the

  7. Shock compression profiles in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Grady, D.E.; Moody, R.L.

    1996-03-01

    An investigation of the shock compression properties of high-strength ceramics has been performed using controlled planar impact techniques. In a typical experimental configuration, a ceramic target disc is held stationary, and it is struck by plates of either a similar ceramic or by plates of a well-characterized metal. All tests were performed using either a single-stage propellant gun or a two-stage light-gas gun. Particle velocity histories were measured with laser velocity interferometry (VISAR) at the interface between the back of the target ceramic and a calibrated VISAR window material. Peak impact stresses achieved in these experiments range from about 3 to 70 GPa. Ceramics tested under shock impact loading include: Al{sub 2}O{sub 3}, AlN, B{sub 4}C, SiC, Si{sub 3}N{sub 4}, TiB{sub 2}, WC and ZrO{sub 2}. This report compiles the VISAR wave profiles and experimental impact parameters within a database-useful for response model development, computational model validation studies, and independent assessment of the physics of dynamic deformation on high-strength, brittle solids.

  8. Shock-resistant scintillation detector

    International Nuclear Information System (INIS)

    Novak, W.P.

    1979-01-01

    A unique scintillation detector unit is disclosed which employs a special light transfer and reflector means that encases and protects the scintillator crystal against high g forces. The light transfer means comprises a flexible silicon rubber optical material bonded between the crystal and the optical window and having an axial thickness sufficient to allow the scintillator to move axially inside the container under high g forces without destroying the bonds. The reflector means comprises a soft elastic silicone rubber sleeve having a multiplicity of closely arranged tapered protrusions radiating toward and engaging the periphery of the scintillator crystal to cushion shocks effectively and having a reflective material, such as aluminum oxide powder, in the spaces between the protrusions. The reflector means provides improved shock absorption because of the uniform support and cushioning action of the protrusions and also provides the detector with high efficiency. The silicon rubber composition is specially compounded to include a large amount of aluminum oxide which enables the rubber to function effectively as a light reflector

  9. Biological therapeutics

    National Research Council Canada - National Science Library

    Greenstein, Ben; Brook, Daniel A

    2011-01-01

    This introductory textbook covers all the main categories of biological medicines, including vaccines, hormonal preparations, drugs for rheumatoid arthritis and other connective tissue diseases, drugs...

  10. Interaction between shock wave and single inertial bubbles near an elastic boundary.

    Science.gov (United States)

    Sankin, G N; Zhong, P

    2006-10-01

    The interaction of laser-generated single inertial bubbles (collapse time = 121 mus) near a silicon rubber membrane with a shock wave (55 MPa in peak pressure and 1.7 mus in compressive pulse duration) is investigated. The interaction leads to directional, forced asymmetric collapse of the bubble with microjet formation toward the surface. Maximum jet penetration into the membrane is produced during the bubble collapse phase with optimal shock wave arrival time and stand-off distance. Such interaction may provide a unique acoustic means for in vivo microinjection, applicable to targeted delivery of macromolecules and gene vectors to biological tissues.

  11. The ''injection problem'' for quasiparallel shocks

    International Nuclear Information System (INIS)

    Zank, G. P.; Rice, W. K. M.; le Roux, J. A.; Cairns, I. H.; Webb, G. M.

    2001-01-01

    For a particle to be accelerated diffusively at a shock by the first-order Fermi acceleration mechanism, the particle must be sufficiently energetic that it can scatter across all the micro- and macrostructure of the shock, experiencing compression between the converging upstream and downstream states. This is the well-known ''injection problem.'' Here the interaction of ions with the ramp of a quasiparallel shock is investigated. Some ions incident on the shock experience specular reflection, caused either by the cross-shock electrostatic potential or by mirroring as the magnetic field is bent and compressed through the ramp. Scattering of reflected ions by self-generated and pre-existing turbulence in the region upstream of the shock then acts to trap backstreaming ions and return them to the ramp, where some experience further reflections. Such repeated reflections and scattering energize a subpopulation of ions up to energies sufficiently large that they can be diffusively shock accelerated. Two ion distributions are considered: pickup ions which are assumed to be described by a shell distribution, are thermal solar wind ions which may be described by a kappa distribution. Injection efficiencies are found analytically to be very high for pickup ions and much lower for thermal solar wind ions, suggesting that this injection mechanism, stochastic reflected ion or SRI acceleration, is a natural precursor for the acceleration of the anomalous cosmic ray component at a quasiparallel shock. While significantly less efficient, SRI acceleration is also viable for thermal solar wind ions described by a kappa distribution

  12. PRECURSORS TO INTERSTELLAR SHOCKS OF SOLAR ORIGIN

    Energy Technology Data Exchange (ETDEWEB)

    Gurnett, D. A.; Kurth, W. S. [University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242 (United States); Stone, E. C.; Cummings, A. C. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Krimigis, S. M.; Decker, R. B. [Applied Physics Laboratory/JHU, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Ness, N. F. [Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Burlaga, L. F., E-mail: donald-gurnett@uiowa.edu [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2015-08-20

    On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the “foreshock” that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

  13. Corporate Policies with Permanent and Transitory Shocks

    NARCIS (Netherlands)

    J-P. Decamps (Jean-Paul); S. Gryglewicz (Sebastian); E. Morellec (Erwan); S. Villeneuve (Stephane)

    2016-01-01

    textabstractWe model the financing, cash holdings, and hedging policies of a firm facing financing frictions and subject to permanent and transitory cash flow shocks. We show that permanent and transitory shocks generate distinct, sometimes opposite, effects on corporate policies and use the model

  14. Shock dynamics in layered periodic media

    KAUST Repository

    Ketcheson, David I.; Leveque, Randall J.

    2012-01-01

    of shock waves in a one-dimensional periodic layered medium by a computational study of time-reversibility and entropy evolution. We find that periodic layered media tend to inhibit shock formation. For small initial conditions and large impedance variation

  15. Particle acceleration and shock wave structure

    International Nuclear Information System (INIS)

    DRURY, L.O'C.

    1989-01-01

    A significant determinant in the large-scale structure and evolution of strong collisionless shocks under astrophysical conditions is probably the acceleration of charged particles. The reaction of these particles on the dynamical structure of the shock wave is discussed both theoretically and in the light of recent numerical calculations. Astrophysical implications for the evolution of supernova remnants, are considered. (author). 15 refs

  16. Laser shock wave and its applications

    Science.gov (United States)

    Yang, Chaojun; Zhang, Yongkang; Zhou, Jianzhong; Zhang, Fang; Feng, Aixin

    2007-12-01

    The technology of laser shock wave is used to not only surface modification but also metal forming. It can be divided into three parts: laser shock processing, laser shock forming (LSF) and laser peenforming(LPF). Laser shock processing as a surface treatment to metals can make engineering components have a residual compressive stress so that it obviously improves their fatigue strength and stress corrosion performances, while laser shock forming (LSF) is a novel technique that is used in plastic deformation of sheet metal recently and Laser peen forming (LPF) is another new sheet metal forming process presented in recent years. They all can be carried out by a high-power and repetition pulse Nd:Glass laser device made by Jiangsu University. Laser shock technology has characterized of ultrahigh pressure and high strain rate (10 6 - 10 7s -1). Now, for different materials, we are able to form different metals to contours and shapes and simultaneity leave their surfaces in crack-resistant compressive stress state. The results show that the technology of laser shock wave can strengthen surface property and prolong fatigue life and especially can deform metals to shapes that could not be adequately made using conventional methods. With the development of the technology of laser shock wave, the applied fields of laser will become greater and greater.

  17. Introduction to Shock Waves and Shock Wave Research

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, William Wyatt [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    M-9 and a number of other organizations at LANL and elsewhere study materials in dynamic processes. Often, this is described as “shock wave research,” but in reality is broader than is implied by that term. Most of our work is focused on dynamic compression and associated phenomena, but you will find a wide variety of things we do that, while related, are not simple compression of materials, but involve a much richer variety of phenomena. This tutorial will introduce some of the underlying physics involved in this work, some of the more common types of phenomena we study, and common techniques. However, the list will not be exhaustive by any means.

  18. Shock Wave Propagation in Functionally Graded Mineralized Tissue

    Science.gov (United States)

    Nelms, Matthew; Hodo, Wayne; Livi, Ken; Browning, Alyssa; Crawford, Bryan; Rajendran, A. M.

    2017-06-01

    In this investigation, the effects of shock wave propagation in bone-like biomineralized tissue was investigated. The Alligator gar (Atractosteus spatula) exoskeleton is comprised of many disparate scales that provide a biological analog for potential design of flexible protective material systems. The gar scale is identified as a two-phase, (1) hydroxyapatite mineral and (2) collagen protein, biological composite with two distinct layers where a stiff, ceramic-like ganoine overlays a soft, highly ductile ganoid bone. Previous experimentations has shown significant softening under compressive loading and an asymmetrical stress-strain response for analogous mineralized tissues. The structural features, porosity, and elastic modulus were determined from high-resolution scanning electron microscopy, 3D micro-tomography, and dynamic nanoindentation experiments to develop an idealized computational model for FE simulations. The numerical analysis employed Gurson's yield criterion to determine the influence of porosity and pressure on material strength. Functional gradation of elastic moduli and certain structural features, such as the sawtooth interface, are explicitly modeled to study the plate impact shock profile for a full 3-D analysis using ABAQUS finite element software.

  19. Shock loading predictions from application of indicial theory to shock-turbulence interactions

    Science.gov (United States)

    Keefe, Laurence R.; Nixon, David

    1991-01-01

    A sequence of steps that permits prediction of some of the characteristics of the pressure field beneath a fluctuating shock wave from knowledge of the oncoming turbulent boundary layer is presented. The theory first predicts the power spectrum and pdf of the position and velocity of the shock wave, which are then used to obtain the shock frequency distribution, and the pdf of the pressure field, as a function of position within the interaction region. To test the validity of the crucial assumption of linearity, the indicial response of a normal shock is calculated from numerical simulation. This indicial response, after being fit by a simple relaxation model, is used to predict the shock position and velocity spectra, along with the shock passage frequency distribution. The low frequency portion of the shock spectra, where most of the energy is concentrated, is satisfactorily predicted by this method.

  20. Shock-induced devolatilization of calcite

    Science.gov (United States)

    Boslough, M. B.; Ahrens, T. J.; Vizgirda, J.; Becker, R. H.; Epstein, S.

    1982-01-01

    Experimental measurements of the release adiabats by Vizgirda (1981) indicate that substantial vaporization takes place upon release from shock pressures of 37 GPa for calcite and 14 GPa for aragonite. The present investigation includes the first controlled partial vaporization experiments on calcite. The experiments were conducted to test the predictions of the release adiabat experiments. The quantities of the gaseous species produced from shocked calcite and their carbon and oxygen isotopic compositions were determined, and the shock-induced effect on the Mn(2+) electron spin resonance spectrum in the shock-recovered calcite was observed. On the basis of the obtained results, it is concluded that shock stresses at the 17-18 GPa level give rise to volatilization of 0.03-0.3 (mole) percent of calcite to CO2 and CO. The devolatilization of calcite occurs at low pressure at significantly lower entropy densities than predicted on the basis of thermodynamic continuum models.

  1. Shock waves in helium at low temperatures

    International Nuclear Information System (INIS)

    Liepmann, H.W.; Torczynski, J.R.

    1986-01-01

    Results are reported from studies of the properties of low temperature He-4 using shock waves as a probe. Ideal shock tube theory is used to show that sonic speeds of Mach 40 are attainable in He at 300 K. Viscosity reductions at lower temperatures minimize boundary layer effects at the side walls. A two-fluid model is described to account for the phase transition which He undergoes at temperatures below 2.2 K, after which the quantum fluid (He II) and the normal compressed superfluid (He I) coexist. Analytic models are provided for pressure-induced shocks in He I and temperature-induced shock waves (called second sound) which appear in He II. The vapor-fluid interface of He I is capable of reflecting second and gasdynamic sound shocks, which can therefore be used as probes for studying phase transitions between He I and He II. 17 references

  2. Analytical extension of curved shock theory

    Science.gov (United States)

    Emanuel, G.

    2018-03-01

    Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.

  3. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  4. Is synthetic biology mechanical biology?

    Science.gov (United States)

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  5. Small-Scale Shock Testing of Propellants and Ingredients

    National Research Council Canada - National Science Library

    Dawley, S

    2004-01-01

    .... The use of small-scale gap testing to evaluate the shock sensitivity of individual propellant ingredients and propellant formulations is a valuable method for experimentally establishing shock...

  6. Surface instabilities in shock loaded granular media

    Science.gov (United States)

    Kandan, K.; Khaderi, S. N.; Wadley, H. N. G.; Deshpande, V. S.

    2017-12-01

    The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pressures considered here, the free-standing dry sand slugs remained stable while the shock loaded surface of the water-saturated sand slug became unstable resulting in mixing of the shocked air and the granular material. By contrast, the PTFE slugs were stable at low pressures but displayed instabilities similar to the water-saturated sand slugs at higher shock pressures. The distal surfaces of the slugs remained stable under all conditions considered here. Eulerian fluid/solid interaction calculations, with the granular material modelled as a Drucker-Prager solid, reproduced the onset of the instabilities as seen in the experiments to a high level of accuracy. These calculations showed that the shock pressures to initiate instabilities increased with increasing material friction and decreasing yield strain. Moreover, the high Atwood number for this problem implied that fluid/solid interaction effects were small, and the initiation of the instability is adequately captured by directly applying a pressure on the slug surface. Lagrangian calculations with the directly applied pressures demonstrated that the instability was caused by spatial pressure gradients created by initial surface perturbations. Surface instabilities are also shown to exist in shock loaded rear-supported granular slugs: these experiments and calculations are used to infer the velocity that free-standing slugs need to acquire to initiate instabilities on their front surfaces. The results presented here, while in an idealised one-dimensional setting, provide physical understanding of the conditions required to

  7. Computational biology

    DEFF Research Database (Denmark)

    Hartmann, Lars Røeboe; Jones, Neil; Simonsen, Jakob Grue

    2011-01-01

    Computation via biological devices has been the subject of close scrutiny since von Neumann’s early work some 60 years ago. In spite of the many relevant works in this field, the notion of programming biological devices seems to be, at best, ill-defined. While many devices are claimed or proved t...

  8. Mesoscopic biology

    Indian Academy of Sciences (India)

    In this paper we present a qualitative outlook of mesoscopic biology where the typical length scale is of the order of nanometers and the energy scales comparable to thermal energy. Novel biomolecular machines, governed by coded information at the level of DNA and proteins, operate at these length scales in biological ...

  9. Quantum Biology

    Directory of Open Access Journals (Sweden)

    Alessandro Sergi

    2009-06-01

    Full Text Available A critical assessment of the recent developmentsof molecular biology is presented.The thesis that they do not lead to a conceptualunderstanding of life and biological systems is defended.Maturana and Varela's concept of autopoiesis is briefly sketchedand its logical circularity avoided by postulatingthe existence of underlying living processes,entailing amplification from the microscopic to the macroscopic scale,with increasing complexity in the passage from one scale to the other.Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces,is criticized. It is suggested that the correct interpretationof quantum dispersion forces (van der Waals, hydrogen bonding, and so onas quantum coherence effects hints at the necessity of includinglong-ranged forces (or mechanisms for them incondensed matter theories of biological processes.Some quantum effects in biology are reviewedand quantum mechanics is acknowledged as conceptually important to biology since withoutit most (if not all of the biological structuresand signalling processes would not even exist. Moreover, it is suggested that long-rangequantum coherent dynamics, including electron polarization,may be invoked to explain signal amplificationprocess in biological systems in general.

  10. Effects of Atwood number on shock focusing in shock-cylinder interaction

    Science.gov (United States)

    Ou, Junfeng; Ding, Juchun; Luo, Xisheng; Zhai, Zhigang

    2018-02-01

    The evolution of shock-accelerated heavy-gas cylinder surrounded by the air with different Atwood numbers (A_t=0.28, 0.50, 0.63) is investigated, concentrating on shock focusing and jet formation. Experimentally, a soap film technique is used to generate an ideal two-dimensional discontinuous gas cylinder with a clear surface, which can guarantee the observation of shock wave movements inside the cylinder. Different Atwood numbers are realized by different mixing ratios of SF_6 and air inside the cylinder. A high-speed schlieren system is adopted to capture the shock motions and jet morphology. Numerical simulations are also performed to provide more information. The results indicate that an inward jet is formed for low Atwood numbers, while an outward jet is generated for high Atwood numbers. Different Atwood numbers will lead to the differences in the relative velocities between the incident shock and the refraction shock, which ultimately results in the differences in shock competition near the downstream pole. The morphology and feature of the jet are closely associated with the position and intensity of shock focusing. The pressure and vorticity contours indicate that the jet formation should be attributed to the pressure pulsation caused by shock focusing, and the jet development is ascribed to the vorticity induction. Finally, a time ratio proposed in the previous work for determining the shock-focusing type is verified by experiments.

  11. Shock Mechanism Analysis and Simulation of High-Power Hydraulic Shock Wave Simulator

    Directory of Open Access Journals (Sweden)

    Xiaoqiu Xu

    2017-01-01

    Full Text Available The simulation of regular shock wave (e.g., half-sine can be achieved by the traditional rubber shock simulator, but the practical high-power shock wave characterized by steep prepeak and gentle postpeak is hard to be realized by the same. To tackle this disadvantage, a novel high-power hydraulic shock wave simulator based on the live firing muzzle shock principle was proposed in the current work. The influence of the typical shock characteristic parameters on the shock force wave was investigated via both theoretical deduction and software simulation. According to the obtained data compared with the results, in fact, it can be concluded that the developed hydraulic shock wave simulator can be applied to simulate the real condition of the shocking system. Further, the similarity evaluation of shock wave simulation was achieved based on the curvature distance, and the results stated that the simulation method was reasonable and the structural optimization based on software simulation is also beneficial to the increase of efficiency. Finally, the combination of theoretical analysis and simulation for the development of artillery recoil tester is a comprehensive approach in the design and structure optimization of the recoil system.

  12. A Prognostic Model for Development of Profound Shock among Children Presenting with Dengue Shock Syndrome.

    Directory of Open Access Journals (Sweden)

    Phung Khanh Lam

    Full Text Available To identify risk factors and develop a prediction model for the development of profound and recurrent shock amongst children presenting with dengue shock syndrome (DSS.We analyzed data from a prospective cohort of children with DSS recruited at the Paediatric Intensive Care Unit of the Hospital for Tropical Disease in Ho Chi Minh City, Vietnam. The primary endpoint was "profound DSS", defined as ≥2 recurrent shock episodes (for subjects presenting in compensated shock, or ≥1 recurrent shock episodes (for subjects presenting initially with decompensated/hypotensive shock, and/or requirement for inotropic support. Recurrent shock was evaluated as a secondary endpoint. Risk factors were pre-defined clinical and laboratory variables collected at the time of presentation with shock. Prognostic model development was based on logistic regression and compared to several alternative approaches.The analysis population included 1207 children of whom 222 (18% progressed to "profound DSS" and 433 (36% had recurrent shock. Independent risk factors for both endpoints included younger age, earlier presentation, higher pulse rate, higher temperature, higher haematocrit and, for females, worse hemodynamic status at presentation. The final prognostic model for "profound DSS" showed acceptable discrimination (AUC=0.69 for internal validation and calibration and is presented as a simple score-chart.Several risk factors for development of profound or recurrent shock among children presenting with DSS were identified. The score-chart derived from the prognostic models should improve triage and management of children presenting with DSS in dengue-endemic areas.

  13. Heat shock proteins of higher plants

    International Nuclear Information System (INIS)

    Key, J.L.; Lin, C.Y.; Chen, Y.M.

    1981-01-01

    The pattern of protein synthesis changes rapidly and dramatically when the growth temperture of soybean seedling tissue is increased from 28 0 C (normal) to about 40 0 C (heat shock). The synthesis of normal proteins is greatly decreased and a new set of proteins, heat shock proteins, is induced. The heat shock proteins of soybean consist of 10 new bands on one-dimensional NaDodSO 4 gels; a more complex pattern is observed on two-dimensional gels. when the tissue is returned to 28 0 C after 4 hr at 40 0 C, there is progressive decline in the synthesis of heat shock proteins and reappearance of a normal pattern of synthesis by 3 or 4 hr. In vitro translation of poly(A) + RNAs isolated from tissued grown at 28 and 40 0 C shows that the heat shock proteins are translated from a ndw set of mRNAs induced at 40 0 C; furthermore, the abundant class mRNAs for many of the normal proteins persist even though they are translated weakly (or not at all) in vivo at 40 or 42.5 0 C. The heat shock response in soybean appears similar to the much-studied heat shock phenomenon in Drosophila

  14. Overview of shock waves in medicine

    Science.gov (United States)

    Cleveland, Robin O.

    2003-10-01

    A brief overview of three applications of shock waves is presented. Shock wave lithotripsy (SWL) has been in clinical use for more than 20 years. In the United States it is used to treat more than 80% of kidney stone cases and has wide acceptance with patients because it is a noninvasive procedure. Despite SWLs enormous success there is no agreement on how shock waves comminute stones. There is also a general acceptance that shock waves lead to trauma to the soft tissue of the kidney. Yet there has been little forward progress in developing lithotripters which provide comminution with less side-effects, indeed the original machine is still considered the gold standard. The last decade has seen the advent of new shock wave devices for treating principally musculoskeletal indications, such as plantar fasciitis, tennis elbow, and bone fractures that do not heal. This is referred to as shock wave therapy (SWT). The mechanisms by which SWT works are even less well understood than SWL and the consequences of bioeffects have also not been studied in detail. Shock waves have also been shown to be effective at enhancing drug delivery into cells and assisting with gene transfection. [Work partially supported by NIH.

  15. Structure of Energetic Particle Mediated Shocks Revisited

    International Nuclear Information System (INIS)

    Mostafavi, P.; Zank, G. P.; Webb, G. M.

    2017-01-01

    The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

  16. Impaired Fracture Healing after Hemorrhagic Shock

    Directory of Open Access Journals (Sweden)

    Philipp Lichte

    2015-01-01

    Full Text Available Impaired fracture healing can occur in severely injured patients with hemorrhagic shock due to decreased soft tissue perfusion after trauma. We investigated the effects of fracture healing in a standardized pressure controlled hemorrhagic shock model in mice, to test the hypothesis that bleeding is relevant in the bone healing response. Male C57/BL6 mice were subjected to a closed femoral shaft fracture stabilized by intramedullary nailing. One group was additionally subjected to pressure controlled hemorrhagic shock (HS, mean arterial pressure (MAP of 35 mmHg for 90 minutes. Serum cytokines (IL-6, KC, MCP-1, and TNF-α were analyzed 6 hours after shock. Fracture healing was assessed 21 days after fracture. Hemorrhagic shock is associated with a significant increase in serum inflammatory cytokines in the early phase. Histologic analysis demonstrated a significantly decreased number of osteoclasts, a decrease in bone quality, and more cartilage islands after hemorrhagic shock. μCT analysis showed a trend towards decreased bone tissue mineral density in the HS group. Mechanical testing revealed no difference in tensile failure. Our results suggest a delay in fracture healing after hemorrhagic shock. This may be due to significantly diminished osteoclast recruitment. The exact mechanisms should be studied further, particularly during earlier stages of fracture healing.

  17. Structure of Energetic Particle Mediated Shocks Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Mostafavi, P.; Zank, G. P. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Webb, G. M. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2017-05-20

    The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

  18. Shock propagation in a heterogeneous medium

    International Nuclear Information System (INIS)

    Elbaz, D.

    2011-01-01

    In the frame of the inertial confinement fusion in direct drive, the use of foams as ablator allows the reduction of hydrodynamic instabilities created on the target by the direct laser irradiation. The foam is made up of carbon (CH) fibers impregnated of cryogenic deuterium-tritium (DT). In the past, studies have been carried out considering this foam to be a homogeneous medium. Yet, the foam presents heterogeneous features. We study the effects of this heterogeneity on the shock velocity when the laser irradiates the target. Thanks to experimental and numerical studies, we show that the shock propagates faster in the heterogeneous medium than in the homogeneous one with the same averaged density. This velocity gap depends on the presence rate of the CH fibers in the foam, the density ratio, the adiabatic coefficient and the foam geometry. We model the foam by different ways, more and more complex. The shock velocity modification is due to the baroclinicity which, during the interaction between the shock front and the interface, creates a vorticity deposition, responsible for the shock acceleration. Accordingly, an interface, which is plane and perpendicular to the front shock, maximizes the vorticity deposition and increases the velocity gaps between heterogeneous and homogeneous media. We found a correlation between the kinetic energy behind the shock front and the velocities relative difference. We compared our results with two analytical models. However, the system is not closed, so we can't for the moment develop a predictive model. (author) [fr

  19. Energetics of the terrestrial bow shock

    Science.gov (United States)

    Hamrin, Maria; Gunell, Herbert; Norqvist, Patrik

    2017-04-01

    The solar wind is the primary energy source for the magnetospheric energy budget. Energy can enter through the magnetopause both as kinetic energy (plasma entering via e.g. magnetic reconnection and impulsive penetration) and as electromagnetic energy (e.g. by the conversion of solar wind kinetic energy into electromagnetic energy in magnetopause generators). However, energy is extracted from the solar wind already at the bow shock, before it encounters the terrestrial magnetopause. At the bow shock the supersonic solar wind is slowed down and heated, and the region near the bow shock is known to host many complex processes, including the accelerating of particles and the generation of waves. The processes at and near the bow shock can be discussed in terms of energetics: In a generator (load) process kinetic energy is converted to (from) electromagnetic energy. Bow shock regions where the solar wind is decelerated correspond to generators, while regions where particles are energized (accelerated and heated) correspond to loads. Recently, it has been suggested that currents from the bow shock generator should flow across the magnetosheath and connect to the magnetospause current systems [Siebert and Siscoe, 2002; Lopez et al., 2011]. In this study we use data from the Magnetospheric MultiScale (MMS) mission to investigate the energetics of the bow shock and the current closure, and we compare with the MHD simulations of Lopez et al., 2011.

  20. Biological desulfurisation

    Energy Technology Data Exchange (ETDEWEB)

    Arena, B.J. [UOP LLC (United States); Benschop, A.; Janssen, A. [Paques Natural Solutions (Netherlands); Kijlstra, S. [Shell Global Solutions (Netherlands)

    2001-03-01

    This article focuses on the biological THIOPAQ process for removing hydrogen sulphide from refinery gases and recovering elemental sulphur. Details are given of the process which absorbs hydrogen sulphide-containing gas in alkaline solution prior to oxidation of the dissolved sulphur to elemental sulphur in a THIOPAQ aerobic biological reactor, with regeneration of the caustic solution. Sulphur handling options including sulphur wash, the drying of the sulphur cake, and sulphur smelting by pressure liquefaction are described. Agricultural applications of the biologically recovered sulphur, and application of the THIOPAQ process to sulphur recovery are discussed.

  1. Radiative shocks with electron thermal conduction

    International Nuclear Information System (INIS)

    Borkowski, Kazimierz.

    1988-01-01

    The authors studies the influence of electron thermal conduction on radiative shock structure for both one- and two-temperature plasmas. The dimensionless ratio of the conductive length to the cooling length determines whether or not conduction is important, and shock jump conditions with conduction are established for a collisionless shock front. He obtains approximate solutions with the assumptions that the ionization state of the gas is constant and the cooling rate is a function of temperature alone. In the absence of magnetic fields, these solutions indicate that conduction noticeably influences normal-abundance interstellar shocks with velocities 50-100 km s -1 and dramatically affects metal-dominated shocks over a wide range of shock velocities. Magnetic fields inhibit conduction, but the conductive energy flux and the corresponding decrease in the post-shock electron temperature may still be appreciable. He calculates detailed steady-state radiative shock models in gas composed entirely of oxygen, with the purpose of explaining observations of fast-moving knots in Cas A and other oxygen-rich supernova remnants (SNRs). The O III ion, whose forbidden emission usually dominates the observed spectra, is present over a wide range of shock velocities, from 100 to 170 kms -1 . All models with conduction have extensive warm photoionization zones, which provides better agreement with observed optical (O I) line strengths. However, the temperatures in these zones could be lowered by (Si II) 34.8 μm and (Ne II) 12.8 μm cooling if Si and Ne are present in appreciable abundance relative to O. Such low temperatures would be inconsistent with the observed (O I) emission in oxygen-rich SNRs

  2. DSMC Computations for Regions of Shock/Shock and Shock/Boundary Layer Interaction

    Science.gov (United States)

    Moss, James N.

    2001-01-01

    This paper presents the results of a numerical study of hypersonic interacting flows at flow conditions that include those for which experiments have been conducted in the Calspan-University of Buffalo Research Center (CUBRC) Large Energy National Shock (LENS) tunnel and the ONERA R5Ch low-density wind tunnel. The computations are made with the direct simulation Monte Carlo (DSMC) method of Bird. The focus is on Mach 9.3 to 11.4 flows about flared axisymmetric configurations, both hollow cylinder flares and double cones. The results presented highlight the sensitivity of the calculations to grid resolution, provide results concerning the conditions for incipient separation, and provide information concerning the flow structure and surface results for the extent of separation, heating, pressure, and skin friction.

  3. Temperature measurements of shock-compressed deuterium

    International Nuclear Information System (INIS)

    Holmes, N.C.; Ross, M.; Nellis, W.J.

    1994-11-01

    The authors measured the temperatures of single and double-shocked D 2 and H 2 up to 85 GPa (0.85 Mbar) and 5,200 K. While single shock temperatures, at pressures to 23 GPa, agree well with previous models, the double shock temperatures are as much as 40% lower than predicted. This is believed to be caused by molecular dissociation, and a new model of the hydrogen EOS at extreme conditions has been developed which correctly predicts their observations. These data and model have important implications for programs which use condensed-phase hydrogen in implosion systems

  4. Recent oil price shock and Tunisian economy

    International Nuclear Information System (INIS)

    Jbir, Rafik; Zouari-Ghorbel, Sonia

    2009-01-01

    The objective of this paper is to study the oil prices-macroeconomy relationship by the analysis of the role of subsidy policy. The vector autoregression (VAR) method was employed to analyze the data over the period 1993 Q1 - 2007 Q3. The results of the model using both linear and non-linear specifications indicate that there is no direct impact of oil price shock on the economic activity. The shock of oil prices affects economic activity indirectly. The most significant channel by which the effects of the shock are transmitted is the government's spending. (author)

  5. Delayed Failure in a Shock Loaded Alumina

    International Nuclear Information System (INIS)

    Cooper, G. A.; Millett, J. C. F.; Bourne, N. K.; Dandekar, D. P.

    2006-01-01

    Manganin stress gauges have been used to measure the lateral stress in a shock-loaded alumina. In combination with known longitudinal stresses, these have been used to determine the shear strength of this material, behind the shock front. The two-step nature of the lateral stress traces shows a slow moving front behind the main shock, behind which shear strength undergoes a significant decrease. Results also show that this front decreases markedly in velocity as the HEL is crossed, suggesting that limited plasticity occurs during inelastic deformation. Finally, comparison of measured shear strengths with other aluminas shows a high degree of agreement

  6. Turbulent energy generated by accelerations and shocks

    International Nuclear Information System (INIS)

    Mikaelian, K.O.

    1986-01-01

    The turbulent energy generated at the interface between two fluids undergoing a constant acceleration or a shock is calculated. Assuming linear density profiles in the mixed region we find E/sub turbulent//E/sub directed/ = 2.3A 2 % (constant acceleration) and 9.3A 2 % (shock), where A is the Atwood number. Diffusion models predict somewhat less turbulent energy and a density profile with a tail extending into the lower density fluid. Eddy sizes are approximately 27% (constant acceleration) and 17% (shock) of the mixing depth into the heavier fluid. 6 refs., 3 figs

  7. Systems Biology

    Indian Academy of Sciences (India)

    IAS Admin

    study and understand the function of biological systems, particu- larly, the response of such .... understand the organisation and behaviour of prokaryotic sys- tems. ... relationship of the structure of a target molecule to its ability to bind a certain ...

  8. Misfortunes never come singly: Structural change, multiple shocks and child malnutrition in rural Senegal.

    Science.gov (United States)

    Lazzaroni, Sara; Wagner, Natascha

    2016-12-01

    This study considers the two most pronounced shocks Senegalese subsistence farmers struggle with, namely increasing purchase prices and droughts. We assess the relationship of these self-reported shocks with child health in a multi-shock approach to account for concomitance of adverse events from the natural, biological, economic and health sphere. We employ a unique farming household panel dataset containing information on children living in poor, rural households in eight regions of Senegal in 2009 and 2011 and account for structural changes occurring between survey periods due to the large scale, national Nutrition Enhancement Program. By zooming in to the micro level we demonstrate that Senegal as a Sahelian country, mainly reliant on subsistence agriculture, is very vulnerable to climate variability and international price developments: According to our conservative estimates, the occurrence of a drought explains 25% of the pooled weight-for-age standard deviation, income losses 31%. Our multi-shock analysis reveals that the shocks are perceived as more severe in 2011 with droughts explaining up to 44% of the standard deviation of child health, increased prices up to 21%. Yet, the concomitance of droughts and increased prices after the structural change, i.e. the Nutrition Enhancement Program, indicates that the health of children experiencing both shocks in 2011 has improved. We argue that these results are driven by the increase in rural household income as theoretically outlined in the agricultural household model. Thus, adequate policy responses to shocks do not only depend on the nature but also on the concomitance of hazardous events. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Underwater electrical wire explosion: Shock wave from melting being overtaken by shock wave from vaporization

    Science.gov (United States)

    Li, Liuxia; Qian, Dun; Zou, Xiaobing; Wang, Xinxin

    2018-05-01

    The shock waves generated by an underwater electrical wire explosion were investigated. A microsecond time-scale pulsed current source was used to trigger the electrical explosion of copper wires with a length of 5 cm and a diameter of 200 μm. The energy-storage capacitor was charged to a relatively low energy so that the energy deposited onto the wire was not large enough to fully vaporize the whole wire. Two shock waves were recorded with a piezoelectric gauge that was located at a position of 100 mm from the exploding wire. The first and weak shock wave was confirmed to be the contribution from wire melting, while the second and stronger shock wave was the contribution from wire vaporization. The phenomenon whereby the first shock wave generated by melting being overtaken by the shock wave due to vaporization was observed.

  10. Multiple spacecraft observations of interplanetary shocks Four spacecraft determination of shock normals

    Science.gov (United States)

    Russell, C. T.; Mellott, M. M.; Smith, E. J.; King, J. H.

    1983-01-01

    ISEE 1, 2, 3, IMP 8, and Prognoz 7 observations of interplanetary shocks in 1978 and 1979 provide five instances where a single shock is observed by four spacecraft. These observations are used to determine best-fit normals for these five shocks. In addition to providing well-documented shocks for future investigations these data allow the evaluation of the accuracy of several shock normal determination techniques. When the angle between upstream and downstream magnetic field is greater than 20 deg, magnetic coplanarity can be an accurate single spacecraft method. However, no technique based solely on the magnetic measurements at one or multiple sites was universally accurate. Thus, the use of overdetermined shock normal solutions, utilizing plasma measurements, separation vectors, and time delays together with magnetic constraints, is recommended whenever possible.

  11. The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis.

    Science.gov (United States)

    Xu, Shu-Jun; Liu, Chun-Jiang; Jiang, Ping-An; Cai, Wei-Min; Wang, Yan

    2009-03-15

    Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 degrees C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 degrees C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs.

  12. The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis

    International Nuclear Information System (INIS)

    Xu Shujun; Liu Chunjiang; Jiang Pingan; Cai Weimin; Wang Yan

    2009-01-01

    Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 deg. C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 deg. C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs

  13. Reliability assessment of competing risks with generalized mixed shock models

    International Nuclear Information System (INIS)

    Rafiee, Koosha; Feng, Qianmei; Coit, David W.

    2017-01-01

    This paper investigates reliability modeling for systems subject to dependent competing risks considering the impact from a new generalized mixed shock model. Two dependent competing risks are soft failure due to a degradation process, and hard failure due to random shocks. The shock process contains fatal shocks that can cause hard failure instantaneously, and nonfatal shocks that impact the system in three different ways: 1) damaging the unit by immediately increasing the degradation level, 2) speeding up the deterioration by accelerating the degradation rate, and 3) weakening the unit strength by reducing the hard failure threshold. While the first impact from nonfatal shocks comes from each individual shock, the other two impacts are realized when the condition for a new generalized mixed shock model is satisfied. Unlike most existing mixed shock models that consider a combination of two shock patterns, our new generalized mixed shock model includes three classic shock patterns. According to the proposed generalized mixed shock model, the degradation rate and the hard failure threshold can simultaneously shift multiple times, whenever the condition for one of these three shock patterns is satisfied. An example using micro-electro-mechanical systems devices illustrates the effectiveness of the proposed approach with sensitivity analysis. - Highlights: • A rich reliability model for systems subject to dependent failures is proposed. • The degradation rate and the hard failure threshold can shift simultaneously. • The shift is triggered by a new generalized mixed shock model. • The shift can occur multiple times under the generalized mixed shock model.

  14. Shock wave physics group (M-6)

    International Nuclear Information System (INIS)

    Morris, C.E.

    1981-01-01

    Experimental facilities and activities of the shock wave physics group at LASL are described. The facilities include a compressed gas gun, two-stage gas gun, high explosive facilities, and a pulsed megagauss field facility

  15. Integrated microelectromechanical gyroscope under shock loads

    Science.gov (United States)

    Nesterenko, T. G.; Koleda, A. N.; Barbin, E. S.

    2018-01-01

    The paper presents a new design of a shock-proof two-axis microelectromechanical gyroscope. Without stoppers, the shock load enables the interaction between the silicon sensor elements. Stoppers were installed in the gyroscope to prevent the contact interaction between electrodes and spring elements with fixed part of the sensor. The contact of stoppers occurs along the plane, thereby preventing the system from serious contact stresses. The shock resistance of the gyroscope is improved by the increase in its eigenfrequency at which the contact interaction does not occur. It is shown that the shock load directed along one axis does not virtually cause the movement of sensing elements along the crosswise axes. Maximum stresses observed in the proposed gyroscope at any loading direction do not exceed the value allowable for silicon.

  16. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

    Full Text Available Rubber is a very flexible material with many desirable properties Which enable its broad use in engineering practice. Rubber or rubber-metal springs are widely used as anti-vibration or anti-shock components in technical systems. Rubber-metal springs are usually realized as a bonded assembly, however especially in shock absorbers, it is possible to realize free contacts between rubber and metal parts. In previous research it authors was observed that friction between rubber and metal in such case have a significant influence on the damping characteristics of shock absorber. This paper analyzes the development process of rubber or rubber-metal shock absorbers realized free contacts between the constitutive parts, starting from the design, construction, testing and operation, with special emphasis on the development of rubber-metal springs for the buffing and draw gear of railway vehicles.

  17. Role of drifts in diffusive shock acceleration

    International Nuclear Information System (INIS)

    Decker, R.B.

    1988-01-01

    The role played by shock-associated drifts during the diffusive acceleration of charged particles at collisionless MHD shocks is evaluated. In the rest frame of the shock, the total energy gained by a particle is shown to result from two coupled acceleration mechanisms, the usual first-order Fermi mechanism and the drift mechanism. When averaged over a distribution of particles, the ratio of the drift-associated energy gain to the total energy is found to be independent of the total energy at a given theta1 (the angle between the shock normal and the unperturbed upstream magnetic field) in agreement with theoretical predictions. No evidence is found for drift-associated deceleration, suggesting that drifts always augment acceleration. 35 references

  18. Shock Thermodynamic Applied Research Facility (STAR)

    Data.gov (United States)

    Federal Laboratory Consortium — The STAR facility, within Sandia's Solid Dynamic Physics Department, is one of a few institutions in the world with a major shock-physics program. This is the only...

  19. Nonequilibrium recombination after a curved shock wave

    Science.gov (United States)

    Wen, Chihyung; Hornung, Hans

    2010-02-01

    The effect of nonequilibrium recombination after a curved two-dimensional shock wave in a hypervelocity dissociating flow of an inviscid Lighthill-Freeman gas is considered. An analytical solution is obtained with the effective shock values derived by Hornung (1976) [5] and the assumption that the flow is ‘quasi-frozen’ after a thin dissociating layer near the shock. The solution gives the expression of dissociation fraction as a function of temperature on a streamline. A rule of thumb can then be provided to check the validity of binary scaling for experimental conditions and a tool to determine the limiting streamline that delineates the validity zone of binary scaling. The effects on the nonequilibrium chemical reaction of the large difference in free stream temperature between free-piston shock tunnel and equivalent flight conditions are discussed. Numerical examples are presented and the results are compared with solutions obtained with two-dimensional Euler equations using the code of Candler (1988) [10].

  20. Critical point anomalies include expansion shock waves

    Energy Technology Data Exchange (ETDEWEB)

    Nannan, N. R., E-mail: ryan.nannan@uvs.edu [Mechanical Engineering Discipline, Anton de Kom University of Suriname, Leysweg 86, PO Box 9212, Paramaribo, Suriname and Process and Energy Department, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands); Guardone, A., E-mail: alberto.guardone@polimi.it [Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Colonna, P., E-mail: p.colonna@tudelft.nl [Propulsion and Power, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)

    2014-02-15

    From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the result is valid for any common pure fluid in which molecular interactions are only short-range, namely, for so-called 3-dimensional Ising-like systems, and under the assumption of thermodynamic equilibrium. In addition to rarefaction shock waves, diverse non-classical effects are admissible, including composite compressive shock-fan-shock waves, due to the change of sign of the fundamental derivative of gasdynamics.

  1. Shock Wave Science and Technology Reference Library

    CERN Document Server

    2007-01-01

    Shock waves in multiphase flows refers to a rich variety of phenomena of interest to physicists, chemists, and fluid dynamicists, as well as mechanical, biomedical and aeronautical engineers. This volume treats shock and expansion waves in (bullet) complex, bubbly liquids (L van Wijngaarden, Y Tomita, V Kedrinskii) and (bullet) cryogenic liquids (M Murakami) and examines the relationship of shock waves with (bullet) phase transitions (A Guha, CF Delale, G Schnerr, MEH van Dongen) (bullet) induced phase transitions (GEA Meier) as well as their interaction with (bullet) solid foams, textiles, porous and granular media (B Skews, DMJ Smeulders, MEH van Dongen, V Golub, O Mirova) All chapters are self-contained, so they can be read independently, although they are of course thematically interrelated. Taken together, they offer a timely reference on shock waves in multiphase flows, including new viewpoints and burgeoning developments. The book will appeal to beginners as well as professional scientists and engineer...

  2. Comments on ''Analysis of spherical imploding shocks''

    International Nuclear Information System (INIS)

    Lazarus, R.B.

    1980-01-01

    It is asserted that Fujimoto and Mishkin's article is incorrect in its claim for a pressure extremum at or behind the shock for all values of γ and in its claim for an analytical form for the similarity exponent

  3. Shock-induced modification of inorganic powders

    International Nuclear Information System (INIS)

    Graham, R.A.; Morosin, B.; Venturini, E.L.; Beauchamp, E.K.; Hammetter, W.F.

    1984-01-01

    The results of studies performed to quantify the characteristics of TiO2, ZrO2 and Si3N4 powders exposed to explosive loading and post-shock analysis are reported. The shocks were produced with plane wave generators and explosive pads impinging on steel disks, a copper recovery fixture, and then the samples. Peak pressures of 13 and 17 GPa were attained, along with 40 GPz at the center of the powder cavity. Data are provided on the changes occurring during the explosive densification and X-ray and paramagnetic studies of the products. Only fractured disks were obtained in the trials. The shock-treated materials were more free flowing than the original powders, which were fluffy. Post-shock annealing was a significant feature of the treated powders

  4. SPECIAL PURPOSE SHOCK TUBE for BLAST ASSESSMENT

    Data.gov (United States)

    Federal Laboratory Consortium — This device is a specially designed shock tube for testing fabric samples in a controlled environment. The device determines the appropriate types of sensors to be...

  5. Collisions on relativistic nuclei: shock waves

    International Nuclear Information System (INIS)

    Gudima, K.K.; Toneev, V.D.

    1976-01-01

    Experiments are analysed which indicate the possible generation of shock waves in collisions of two nuclei. Another interpretation of these data is proposed and the concerned new experiments are discussed

  6. Analysis of Z Pinch Shock Wave Experiments

    International Nuclear Information System (INIS)

    Asay, James; Budge, Kent G.; Chandler, Gordon; Fleming, Kevin; Hall, Clint; Holland, Kathleen; Konrad, Carl; Lawrence, Jeffery; Trott, Wayne; Trucano, Timothy

    1999-01-01

    In this paper, we report details of our computational study of two shock wave physics experiments performed on the Sandia Z machine in 1998. The novelty of these particular experiments is that they represent the first successful application of VISAR interferometry to diagnose shock waves generated in experimental payloads by the primary X-ray pulse of the machine. We use the Sandia shock-wave physics code ALEGRA to perform the simulations reported in this study. Our simulations are found to be in fair agreement with the time-resolved VISAR experimental data. However, there are also interesting and important discrepancies. We speculate as to future use of time-resolved shock wave data to diagnose details of the Z machine X-ray pulse in the future

  7. Shock Tube Measurements for Liquid Fuels Combustion

    National Research Council Canada - National Science Library

    Hanson, Ronald K

    2006-01-01

    ...) fundamental studies of fuel spray evaporation rates and ignition times of low-vapor pressure fuels such as JP-8, diesel fuel and normal alkane surrogates in a new aerosol shock tube using state...

  8. Condensed matter at high shock pressures

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-07-12

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N/sub 2/, CO, SiO/sub 2/-aerogel, H/sub 2/O, and C/sub 6/H/sub 6/. The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab.

  9. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book, as a volume of the Shock Wave Science and Technology Reference Library, is primarily concerned with detonation waves or compression shock waves in reactive heterogeneous media, including mixtures of solid, liquid and gas phases. The topics involve a variety of energy release and control processes in such media - a contemporary research field that has found wide applications in propulsion and power, hazard prevention as well as military engineering. The six extensive chapters contained in this volume are: - Spray Detonation (SB Murray and PA Thibault) - Detonation of Gas-Particle Flow (F Zhang) - Slurry Detonation (DL Frost and F Zhang) - Detonation of Metalized Composite Explosives (MF Gogulya and MA Brazhnikov) - Shock-Induced Solid-Solid Reactions and Detonations (YA Gordopolov, SS Batsanov, and VS Trofimov) - Shock Ignition of Particles (SM Frolov and AV Fedorov) Each chapter is self-contained and can be read independently of the others, though, they are thematically interrelated. They offer a t...

  10. Comparative review of bow shocks and magnetopauses

    International Nuclear Information System (INIS)

    Lepping, R.P.

    1984-04-01

    Bow shock and magnetopauses formation is discussed. Plasma and magnetic field environments of all the planets from Mercury to Saturn were measured. It was found that all the planets have bow shocks and almost all have a magnetopause. Venus is the only planet with no measurable intrinsic magnetic field and the solar wind interacts directly with Venus ionosphere. The bow shock characteristics depend on the changing solar wind conditions. The shape of a magnetopause or any obstacle to flow depends on the three dimensional pressure profile that it presents to the solar wind. Jupiter is unusual because of the considerable amount of plasma which is contained in its magnetosphere. Magentopause boundaries in ecliptic plane projection are modelled by segments of ellipses, matched to straight lines for the magnetotool boundaries or parabolas. Specific properties of known planetary bow shocks and magnetopauses are reviewed

  11. Medical and biomedical applications of shock waves

    CERN Document Server

    Loske, Achim M

    2017-01-01

    This book provides current, comprehensive, and clear explanations of the physics behind medical and biomedical applications of shock waves. Extracorporeal shock wave lithotripsy is one of the greatest medical advances of our time, and its techniques and clinical devices are continuously evolving. Further research continues to improve the understanding of calculi fragmentation and tissue-damaging mechanisms. Shock waves are also used in orthopedics and traumatology. Possible applications in oncology, cardiology, dentistry, gene therapy, cell transfection, transformation of fungi and bacteria, as well as the inactivation of microorganisms are promising approaches for clinical treatment, industrial applications and research. Medical and Biomedical Applications of Shock Waves is useful as a guide for students, technicians and researchers working in universities and laboratories. Chemists, biologists, physicians and veterinarians, involved in research or clinical practice will find useful advice, but also engineer...

  12. Relative locations of the bow shocks of the terrestrial planets

    International Nuclear Information System (INIS)

    Russell, C.T.

    1977-01-01

    The observed bow shock encounters at Mercury, Venus and Mars are least square fit using the same technique so that their sizes and shapes can be intercompared. The shock front of Mercury most resembles the terrestrial shock in shape, and the shock stand off distance is consistent with the observed moment. The shapes of the Venus and Mars shock fronts more resemble each other than the earth's and the stand off distances are consistent with direct interaction of the solar wind with the ionosphere on the dayside. The Venus shock is closer to the planet than the Mars shock suggesting more absorption of the solar wind at Venus

  13. Orientation Dependence in Molecular Dynamics Simulations of Shocked Single Crystals

    International Nuclear Information System (INIS)

    Germann, Timothy C.; Holian, Brad Lee; Lomdahl, Peter S.; Ravelo, Ramon

    2000-01-01

    We use multimillion-atom molecular dynamics simulations to study shock wave propagation in fcc crystals. As shown recently, shock waves along the direction form intersecting stacking faults by slippage along {111} close-packed planes at sufficiently high shock strengths. We find even more interesting behavior of shocks propagating in other low-index directions: for the case, an elastic precursor separates the shock front from the slipped (plastic) region. Shock waves along the direction generate a leading solitary wave train, followed (at sufficiently high shock speeds) by an elastic precursor, and then a region of complex plastic deformation. (c) 2000 The American Physical Society

  14. THE EFFECTS OF AREA CONTRACTION ON SHOCK WAVE STRENGTH AND PEAK PRESSURE IN SHOCK TUBE

    Directory of Open Access Journals (Sweden)

    A. M. Mohsen

    2012-06-01

    Full Text Available This paper presents an experimental investigation into the effects of area contraction on shock wave strength and peak pressure in a shock tube. The shock tube is an important component of the short duration, high speed fluid flow test facility, available at the Universiti Tenaga Nasional (UNITEN, Malaysia. The area contraction was facilitated by positioning a bush adjacent to the primary diaphragm section, which separates the driver and driven sections. Experimental measurements were performed with and without the presence of the bush, at various diaphragm pressure ratios, which is the ratio of air pressure between the driver (high pressure and driven (low pressure sections. The instantaneous static pressure variations were measured at two locations close to the driven tube end wall, using high sensitivity pressure sensors, which allow the shock wave strength, shock wave speed and peak pressure to be analysed. The results reveal that the area contraction significantly reduces the shock wave strength, shock wave speed and peak pressure. At a diaphragm pressure ratio of 10, the shock wave strength decreases by 18%, the peak pressure decreases by 30% and the shock wave speed decreases by 8%.

  15. Waves and Instabilities in Collisionless Shocks

    Science.gov (United States)

    1984-04-01

    occur in the electron foreshock and are driven by suprathermal electrons escaping into the region upstream of the shock. Both the ion-acoustic and...ULF waves occur in the ion foreshock and are associated with ions streaming into the region upstream of 11 the shock. The region downstream of the...the discussion of these waves it is useful to distinguish two regions, called the electron foreshock and the ion foreshock . Because the particles

  16. The Dynamic Quasiperpendicular Shock: Cluster Discoveries

    Czech Academy of Sciences Publication Activity Database

    Krasnoselskikh, V.; Balikhin, M.; Walker, S. N.; Schwartz, S.; Sundkvist, D.; Lobzin, V.; Gedalin, M.; Bale, S. D.; Mozer, F.; Souček, Jan; Hobara, Y.; Comisel, H.

    2013-01-01

    Roč. 178, 2-4 (2013), s. 535-598 ISSN 0038-6308 Institutional support: RVO:68378289 Keywords : collisionless shocks * waves in plasmas * nonstationarity * shock scales * plasma heating and acceleration * wave-particle interactions Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 5.874, year: 2013 http://link.springer.com/article/10.1007%2Fs11214-013-9972-y

  17. Flow control for oblique shock wave reflections

    OpenAIRE

    Giepman, R.H.M.

    2016-01-01

    Shock wave-boundary layer interactions are prevalent in many aerospace applications that involve transonic or supersonic flows. Such interactions may lead to boundary layer separation, flow unsteadiness and substantial losses in the total pressure. Flow control techniques can help to mitigate these adverse effects and stabilize the interaction. This thesis focuses on passive flow control techniques for oblique shock wave reflections on flat plates and presents experimental results for both la...

  18. Public Investment, Revenue Shocks, and Borrowing Restrictions

    OpenAIRE

    Büttner, Thiess; Wildasin, David E.

    2010-01-01

    This paper lays out a theory of taxation and public investment in an intertemporal setting under conditions of revenue shocks. Without borrowing restrictions, the optimal policy is characterized by smooth time paths of taxes and public investment. While the introduction of formal borrowing restrictions leads to some precautionary savings, it gives rise to fluctuations in public investment in response to adverse but also favorable revenue shocks. This theoretical result is tested empirically u...

  19. Optical Probes for Laser Induced Shocks

    Science.gov (United States)

    1992-03-01

    target by the strong water. As the shock passes the material interface, it is pressure transients. only partially transmitted. The shock pressure is...T. Swimm , J. Appl. Phys. 61, evaporated, t1137(1987). vapor flow substantially. The coupling coefficient thus de- 3 v. A. Batanov and V. B. Fedorov...Waist-Surface Distance [mm] isurface on the drilling mechanismC Positive ( negative ) To roughly estimate the total recoil momentum positions

  20. Fast Electrocardiogram Amplifier Recovery after Defibrillation Shock

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky

    2005-04-01

    Full Text Available A procedure for fast ECG amplifier recovery after defibrillation shocks was developed and simulated in the MATLAB environment. Exponentially decaying post-shock voltages have been recorded. Signals from the AHA database are taken and mixed with the recorded exponential disturbances. The algorithm applies moving averaging (comb filter on the compound input signal, thereby obtaining the samples of the disturbance. They are currently subtracted from the input signal. The results obtained show that its recovery is practically instantaneous.

  1. Pressurized-thermal-shock experiments

    International Nuclear Information System (INIS)

    Whitman, G.D.; McCulloch, R.W.

    1982-01-01

    The primary objective of the ORNL pressurized-thermal-shock (PTS) experiments is to verify analytical methods that are used to predict the behavior of pressurized-water-reactor vessels under these accident conditions involving combined pressure and thermal loading. The criteria on which the experiments are based are: scale large enough to attain effective flaw border triaxial restraint and a temperature range sufficiently broad to produce a progression from frangible to ductile behavior through the wall at a given time; use of materials that can be completely characterized for analysis; stress states comparable to the actual vessel in zones of potential flaw extension; range of behavior to include cleavage initiation and arrest, cleavage initiation and arrest on the upper shelf, arrest in a high K/sub I/ gradient, warm prestressing, and entirely ductile behavior; long and short flaws with and without stainless steel cladding; and control of loads to prevent vessel burst, except as desired. A PTS test facility is under construction which will enable the establishment and control of wall temperature, cooling rate, and pressure on an intermediate test vessel (ITV) in order to simulate stress states representative of an actual reactor pressure vessel

  2. A FOCUSED TRANSPORT APPROACH TO THE TIME-DEPENDENT SHOCK ACCELERATION OF SOLAR ENERGETIC PARTICLES AT A FAST TRAVELING SHOCK

    International Nuclear Information System (INIS)

    Le Roux, J. A.; Webb, G. M.

    2012-01-01

    Some of the most sophisticated models for solar energetic particle (SEP) acceleration at coronal mass ejection driven shocks are based on standard diffusive shock acceleration theory. However, this theory, which only applies when SEP pitch-angle anisotropies are small, might have difficulty in describing first-order Fermi acceleration or the shock pre-heating and injection of SEPs into first-order Fermi acceleration accurately at lower SEP speeds where SEP pitch-angle anisotropies upstream near the shock can be large. To avoid this problem, we use a time-dependent focused transport model to reinvestigate first-order Fermi acceleration at planar parallel and quasi-parallel spherical traveling shocks between the Sun and Earth with high shock speeds associated with rare extreme gradual SEP events. The focused transport model is also used to investigate and compare three different shock pre-heating mechanisms associated with different aspects of the nonuniform cross-shock solar wind flow, namely, the convergence of the flow (adiabatic compression), the shear tensor of the flow, and the acceleration of the flow, and a fourth shock pre-heating mechanism associated with the cross-shock electric field, to determine which pre-heating mechanism contributes the most to injecting shock pre-heated source particles into the first-order Fermi acceleration process. The effects of variations in traveling shock conditions, such as increasing shock obliquity and shock slowdown, and variations in the SEP source with increasing shock distance from the Sun on the coupled processes of shock pre-heating, injection, and first-order Fermi acceleration are analyzed. Besides the finding that the cross-shock acceleration of the solar wind flow yields the dominant shock pre-heating mechanism at high shock speeds, we find that first-order Fermi acceleration at fast traveling shocks differs in a number of respects from the predictions and assumptions of standard steady-state diffusive shock

  3. dFOXO Activates Large and Small Heat Shock Protein Genes in Response to Oxidative Stress to Maintain Proteostasis in Drosophila.

    Science.gov (United States)

    Donovan, Marissa R; Marr, Michael T

    2016-09-02

    Maintaining protein homeostasis is critical for survival at the cellular and organismal level (Morimoto, R. I. (2011) Cold Spring Harb. Symp. Quant. Biol. 76, 91-99). Cells express a family of molecular chaperones, the heat shock proteins, during times of oxidative stress to protect against proteotoxicity. We have identified a second stress responsive transcription factor, dFOXO, that works alongside the heat shock transcription factor to activate transcription of both the small heat shock protein and the large heat shock protein genes. This expression likely protects cells from protein misfolding associated with oxidative stress. Here we identify the regions of the Hsp70 promoter essential for FOXO-dependent transcription using in vitro methods and find a physiological role for FOXO-dependent expression of heat shock proteins in vivo. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Thermal shock investigation of silicon nitride

    International Nuclear Information System (INIS)

    Ziegler, G.; Leucht, R.

    1977-01-01

    In this work, the thermal shock properties of commercial reaction-bonded Si 3 N 4 quality material (RBSN), of commercial hot-pressed Si 3 N 4 (HPSN) and of different laboratory grades of hot-pressed Si 3 N 4 were examined. The thermal shock properties of RBSN quality material differ according to the structure considerably: The critical temperature difference for sample crossections of 5 x 5 or 6 x 6 mm after quenching in oil lies between 730 0 C and over 1400 0 C. The best thermal shock properties are shown by high density RBSN quality material having very fine pores and high initial strength. The results indicate that for RBSN large pores and density inhomogenities are responsible for bad thermal shock properties. Resistance to fast temperature change is higher for hot-pressed Si 3 N 4 than for RBSN quality material. In HPSN, the thermal shock results show dependence on structure. High MgO content and the associated coarse rod-shaped configuration of the β phase and structural inhomogenities affect the thermal shock properties in an adverse way. (orig.) [de

  5. Mechanical Properties of Shock-Damaged Rocks

    Science.gov (United States)

    He, Hongliang; Ahrens, T. J.

    1994-01-01

    Stress-strain tests were performed both on shock-damaged gabbro and limestone. The effective Young's modulus decreases with increasing initial damage parameter value, and an apparent work-softening process occurs prior to failure. To further characterize shock-induced microcracks, the longitudinal elastic wave velocity behavior of shock-damaged gabbro in the direction of compression up to failure was measured using an acoustic transmission technique under uniaxial loading. A dramatic increase in velocity was observed for the static compressive stress range of 0-50 MPa. Above that stress range, the velocity behavior of lightly damaged (D(sub 0) less than 0.1) gabbro is almost equal to unshocked gabbro. The failure strength of heavily-damaged (D(sub 0) greater than 0.1) gabbro is approx. 100-150 MPa, much lower than that of lightly damaged and unshocked gabbros (approx. 230-260 MPa). Following Nur's theory, the crack shape distribution was analyzed. The shock-induced cracks in gabbro appear to be largely thin penny-shaped cracks with c/a values below 5 x 10(exp -4). Moreover, the applicability of Ashby and Sammis's theory relating failure strength and damage parameter of shock-damaged rocks was examined and was found to yield a good estimate of the relation of shock-induced deficit in elastic modulus with the deficit in compressive strength.

  6. Emissive spectra of shock-heated argon

    International Nuclear Information System (INIS)

    Tang Jingyou; Gu Yan; Peng Qixian; Bai Yulin; Li Ping

    2003-01-01

    To study the radiant properties of argon under weak shock compression, an aluminum target filled with gaseous argon at ambient states was impacted by a tungsten alloy projectile which was launched from a two-stage light gun to 2.00 km/s. The radiant signals of single shock-compressed argon were recorded by a six-channel pyrometer and oscilloscopes, which varied with time linearly for the five channels from 405 nm to 700 nm and exponentially for the channel 800 nm, and the corresponding velocity of shock wave was determined to be 4.10 ± 0.09 km/s. By the present experiment, it has been shown that the absorbability of the shock-heated argon is low for visual light and the optical depths of argon gas turn from thin to thick as wavelengths gradually increase. The time-resolved spectra in the rising-front of the radiant signal in the re-shocked argon were recorded by means of an OMA, and strong emissive spectrum bands near 450 nm light-wave length but no linear spectrum were found. The emissive spectrum properties of shock-compression argon were qualitatively explained by the state parameters and ionization degree

  7. Pick-up ion energization at the termination shock

    Energy Technology Data Exchange (ETDEWEB)

    Gary, S Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Wu, Pin [BOSTON UNIV.; Schwadron, N A [BOSTON UNIV.

    2009-01-01

    One-dimensional hybrid simulations are used to investigate how pickup ions are energized at the perpendicular termination shock. Contrary to previous models based on pickup ion energy gain by repeated crossings of the shock front (shock surfing) or due to a reforming shock front, the present simulations show that pickup ion energy gain involves a gyro-phasedependent interaction with the inhomogeneous motional electric field at the shock. The process operates at all relative concentrations of pickup ion density.

  8. [Biological agents].

    Science.gov (United States)

    Amano, Koichi

    2009-03-01

    There are two types of biological agents for the treatment of rheumatoid arthritis (RA); monoclonal antibodies and recombinant proteins. Among the latter, etanercept, a recombinant fusion protein of soluble TNF receptor and IgG was approved in 2005 in Japan. The post-marketing surveillance of 13,894 RA patients revealed the efficacy and safety profiles of etanercept in the Japanese population, as well as overseas studies. Abatacept, a recombinant fusion protein of CTLA4 and IgG, is another biological agent for RA. Two clinical trials disclosed the efficacy of abatacept for difficult-to-treat patients: the AIM for MTX-resistant cases and the ATTAIN for patients who are resistant to anti-TNF. The ATTEST trial suggested abatacept might have more acceptable safety profile than infliximab. These biologics are also promising for the treatment of RA for not only relieving clinical symptoms and signs but retarding structural damage.

  9. Biological preconcentrator

    Science.gov (United States)

    Manginell, Ronald P [Albuquerque, NM; Bunker, Bruce C [Albuquerque, NM; Huber, Dale L [Albuquerque, NM

    2008-09-09

    A biological preconcentrator comprises a stimulus-responsive active film on a stimulus-producing microfabricated platform. The active film can comprise a thermally switchable polymer film that can be used to selectively absorb and desorb proteins from a protein mixture. The biological microfabricated platform can comprise a thin membrane suspended on a substrate with an integral resistive heater and/or thermoelectric cooler for thermal switching of the active polymer film disposed on the membrane. The active polymer film can comprise hydrogel-like polymers, such as poly(ethylene oxide) or poly(n-isopropylacrylamide), that are tethered to the membrane. The biological preconcentrator can be fabricated with semiconductor materials and technologies.

  10. Macroeconomic impacts of oil price shocks in Asian economies

    International Nuclear Information System (INIS)

    Cunado, Juncal; Jo, Soojin; Perez de Gracia, Fernando

    2015-01-01

    This paper analyzes the macroeconomic impact of structural oil shocks in four of the top oil-consuming Asian economies, using a VAR model. We identify three different structural oil shocks via sign restrictions: an oil supply shock, an oil demand shock driven by global economic activity and an oil-specific demand shock. The main results suggest that economic activity and prices respond very differently to oil price shocks depending on their types. In particular, an oil supply shock has a limited impact, while a demand shock driven by global economic activity has a significant positive effect in all four Asian countries examined. Our finding also includes that policy tools such as interest rates and exchange rates help mitigating the effects of supply shocks in Japan and Korea; however, they can be more actively used in response to demands shocks. - Highlights: • We analyze the effects of three structural oil price shocks on Asian economies. • Supply shocks have limited impact on the economic activity of Asian economies examined. • Demand shocks due to economic activity boosts GDP of all economies. • CPIs in India and Indonesia were only marginally affected by oil price shocks. • Monetary and exchange rate tools help mitigating supply shocks in Korea and Japan.

  11. Shock-wave induced mechanoluminescence: A new technique for studying effects of shock pressure on crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, B.P.; Parganiha, S.; Sonwane, V.D. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh (India); Chandra, V.K. [Department of Electrical and Electronics Engineering, Chhatrapati Shivaji Institute of Technology, Shivaji Nagar, Kolihapuri, Durg 491001, Chhattisgarh (India); Jha, Piyush, E-mail: piyushjha22@rediffmail.com [Department of Applied Physics, Raipur Institute of Technology, Chhatauna, Mandir Hasuad, Raipur 492101, Chhattisgarh (India); Baghel, R.N. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, Chhattisgarh (India)

    2016-10-15

    The impact of a projectile propelled to velocities in the range of 0.5–2.5 km/s on to a target (X-cut quartz crystal) produces shock waves travelling at velocity of nearly 10 km/s in target, in which intense mechanoluminescence (ML) pulses of microsecond duration are produced, both in compression and post-compression conditions. The piezoelectric field produced due to surface charges of fractured target, causes band bending and subsequently, the free charge carriers are generated in the respective bands and the emission of ML occurs. The ML appears after a delay time t{sub th} whose value decreases with increasing value of the shock pressure. Initially, the ML intensity increases with the shock pressure because of the creation of more surfaces; however, for higher values of the shock pressure, the ML intensity tends to attain a saturation value because of the hardening of the crystals due to the creation of small crystallites in which the creation of new surfaces becomes difficult. The ratio between peak ML intensity in the uncompressed region and the maximum ML intensity in the compressed region decreases with increasing shock pressure because more defects produced at high pressure generate higher barrier for the relaxation of blocked cracks under compression. The expressions derived for characteristics of shock-induced ML are able to explain satisfactorily the experimental results. Shock-wave velocity, shock pressure, transit time, lifetime of electrons in conduction band, etc. can be determined by the shock-induced ML.As such, the shock-induced ML provides a new optical technique for the studies of materials under shock pressure.

  12. Renal tissue damage induced by focused shock waves

    Science.gov (United States)

    Ioritani, N.; Kuwahara, M.; Kambe, K.; Taguchi, K.; Saitoh, T.; Shirai, S.; Orikasa, S.; Takayama, K.; Lush, P. A.

    1990-07-01

    Biological evidence of renal arterial wall damage induced by the microjet due to shock wave-cavitation bubble interaction was demonstrated in living dog kidneys. We also intended to clarify the mechanism of renal tissue damage and the effects of different conditions of shock wave exposure (peak pressure of focused area, number of shots, exposure rate) on the renal tissue damage in comparison to stone disintegration. Disruption of arterial wall was the most remarkable histological change in the focused area of the kidneys. This lesion appeared as if the wall had been punctured by a needle. Large hematoma formation in the renal parenchym, and interstitial hemorrhage seemed to be the results of the arterial lesion. This arterial disorder also led to ischemic necrosis of the tubules surrounding the hematoma. Micro-angiographic examination of extracted kidneys also proved such arterial puncture lesions and ischemic lesions. The number of shots required for model stone disintegration was not inversely proportional to peak pressure. It decreased markedly when peak pressure was above 700 bar. Similarly thenumber of shots for hematoma formation was not inversely proportional to peak pressure, however, this decreased markedly above 500 bar. These results suggested that a hematoma could be formed under a lower peak pressure than that required for stone disintegration.

  13. Detecting cavitation in vivo from shock-wave therapy devices

    Science.gov (United States)

    Matula, Thomas J.; Yu, Jinfei; Bailey, Michael R.

    2005-04-01

    Extracorporeal shock-wave therapy (ESWT) has been used as a treatment for plantar faciitis, lateral epicondylitis, shoulder tendonitis, non-unions, and other indications where conservative treatments have been unsuccessful. However, in many areas, the efficacy of SW treatment has not been well established, and the mechanism of action, particularly the role of cavitation, is not well understood. Research indicates cavitation plays an important role in other ultrasound therapies, such as lithotripsy and focused ultrasound surgery, and in some instances, cavitation has been used as a means to monitor or detect a biological effect. Although ESWT can generate cavitation easily in vitro, it is unknown whether or not cavitation is a significant factor in vivo. The purpose of this investigation is to use diagnostic ultrasound to detect and monitor cavitation generated by ESWT devices in vivo. Diagnostic images are collected at various times during and after treatment. The images are then post-processed with image-processing algorithms to enhance the contrast between bubbles and surrounding tissue. The ultimate goal of this research is to utilize cavitation as a means for optimizing shock wave parameters such as amplitude and pulse repetition frequency. [Work supported by APL internal funds and NIH DK43881 and DK55674.

  14. A Reverse Shock in GRB 160509A

    Science.gov (United States)

    Laskar, Tanmoy; Alexander, Kate D.; Berger, Edo; Fong, Wen-fai; Margutti, Raffaella; Shivvers, Isaac; Williams, Peter K. G.; Kopač, Drejc; Kobayashi, Shiho; Mundell, Carole; Gomboc, Andreja; Zheng, WeiKang; Menten, Karl M.; Graham, Melissa L.; Filippenko, Alexei V.

    2016-12-01

    We present the second multi-frequency radio detection of a reverse shock in a γ-ray burst. By combining our extensive radio observations of the Fermi-Large Area Telescope γ-ray burst 160509A at z = 1.17 up to 20 days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at ≲10 days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of {n}0≈ {10}-3 {{cm}}-3, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, N H ≈ 1.5 × 1022 {{cm}}-2, and a high rest-frame optical extinction, A V ≈ 3.4 mag. We identify a jet break in the X-ray light curve at {t}{jet}≈ 6 {days}, and thus derive a jet opening angle of {θ }{jet}≈ 4^\\circ , yielding a beaming-corrected kinetic energy and radiated γ-ray energy of {E}{{K}}≈ 4× {10}50 erg and {E}γ ≈ 1.3× {10}51 erg (1-104 keV, rest frame), respectively. Consistency arguments connecting the forward shocks and reverse shocks suggest a deceleration time of {t}{dec} ≈ 460 s ≈ T 90, a Lorentz factor of {{Γ }}({t}{dec})≈ 330, and a reverse-shock-to-forward-shock fractional magnetic energy density ratio of {R}{{B}}\\equiv {ɛ }{{B},{RS}}/{ɛ }{{B},{FS}}≈ 8. Our study highlights the power of rapid-response radio observations in the study of the properties and dynamics of γ-ray burst ejecta.

  15. Pressurized-thermal-shock technology

    International Nuclear Information System (INIS)

    Dickson, T.L.

    1991-01-01

    It was recognized at the time the original Issues on Pressurized Thermal Shock (IPTS) studies were conducted that distinct vertical plumes of cooling water form beneath the cold leg inlet nozzles during those particular transients that exhibit fluid/thermal stratification. The formation of these plumes (referred to as thermal streaming) induces a time-dependent circumferential temperature variation on the inner surface of the Reactor Pressure Vessel (RPV) wall that creates an axial stress component. This axial stress component is in addition to the axial stress components induced by time-dependent radial temperature variation through the wall thickness and the time-dependent pressure transient. This additional axial stress component will result in a larger axial stress resultant that results in a larger stress-intensity factor acting on circumferential flaws, thus reducing the fracture margin for circumferential flaws. Although this was recognized at the time of the original IPTS study, the contribution appeared to be relatively small; therefore, it was neglected. The original IPTS studies were performed with OCA-P, a computer program developed at ORNL to analyze the cleavage fracture response of a nuclear RPV subjected to PTS loading. OCA-P is a one-dimensional (1-D) finite-element code that analyzes the stresses and stress-intensity factors (axial and tangential) resulting from the pressure and the radial temperature variation through the wall thickness only. The HSST Program is investigating the potential effects of thermal-streaming-induced stresses in circumferential welds on the reactor vessel PTS analyses. The initial phase of this investigation focused on an evaluation of the available thermal-hydraulic data and analyses results. The objective for the initial phase of the investigation is to evaluate thermal-streaming behavior under conditions relevant to the operation of U.S. PWRs and chracterize any predicted thermal-streaming plumes

  16. Environmental biology

    International Nuclear Information System (INIS)

    Tschumi, P.A.

    1981-01-01

    Environmental biology illustrates the functioning of ecosystems and the dynamics of populations with many examples from limnology and terrestrial ecology. On this basis, present environmental problems are analyzed. The present environmental crisis is seen as a result of the failure to observe ecological laws. (orig.) [de

  17. Biological timekeeping

    DEFF Research Database (Denmark)

    Lloyd, David

    2016-01-01

    , the networks that connect differenttime domains and the oscillations, rhythms and biological clocks that coordinate andsynchronise the complexity of the living state.“It is the pattern maintained by this homeostasis, which is the touchstone ofour personal identity. Our tissues change as we live: the food we...

  18. Scaffolded biology.

    Science.gov (United States)

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

  19. Biological digestion

    International Nuclear Information System (INIS)

    Rosevear, A.

    1988-01-01

    This paper discusses the biological degradation of non-radioactive organic material occurring in radioactive wastes. The biochemical steps are often performed using microbes or isolated enzymes in combination with chemical steps and the aim is to oxidise the carbon, hydrogen, nitrogen and sulphur to their respective oxides. (U.K.)

  20. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  1. Effects of response-shock interval and shock intensity on free-operant avoidance responding in the pigeon1

    Science.gov (United States)

    Klein, Marty; Rilling, Mark

    1972-01-01

    Two experiments investigated free-operant avoidance responding with pigeons using a treadle-pressing response. In Experiment I, pigeons were initially trained on a free-operant avoidance schedule with a response-shock interval of 32 sec and a shock-shock interval of 10 sec, and were subsequently exposed to 10 values of the response-shock parameter ranging from 2.5 to 150 sec. The functions relating response rate to response-shock interval were similar to the ones reported by Sidman in his 1953 studies employing rats, and were independent of the order of presentation of the response-shock values. Shock rates decreased as response-shock duration increased. In Experiment II, a free-operant avoidance schedule with a response-shock interval of 20 sec and a shock-shock interval of 5 sec was used, and shock intensities were varied over five values ranging from 2 to 32 mA. Response rates increased markedly as shock intensity increased from 2 to 8 mA, but rates changed little with further increases in shock intensity. Shock rates decreased as intensity increased from 2 to 8 mA, and showed little change as intensity increased from 8 to 32 mA. PMID:4652617

  2. Role of echocardiography in reducing shock reversal time in pediatric septic shock: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ahmed A. EL-Nawawy

    Full Text Available Abstract Objective: To evaluate the role of echocardiography in reducing shock reversal time in pediatric septic shock. Methods: A prospective study conducted in the pediatric intensive care unit of a tertiary care teaching hospital from September 2013 to May 2016. Ninety septic shock patients were randomized in a 1:1 ratio for comparing the serial echocardiography-guided therapy in the study group with the standard therapy in the control group regarding clinical course, timely treatment, and outcomes. Results: Shock reversal was significantly higher in the study group (89% vs. 67%, with significantly reduced shock reversal time (3.3 vs. 4.5 days. Pediatric intensive care unit stay in the study group was significantly shorter (8 ± 3 vs. 14 ± 10 days. Mortality due to unresolved shock was significantly lower in the study group. Fluid overload was significantly lower in the study group (11% vs. 44%. In the study group, inotropes were used more frequently (89% vs. 67% and initiated earlier (12[0.5-24] vs. 24[6-72] h with lower maximum vasopressor inotrope score (120[30-325] vs. 170[80-395], revealing predominant use of milrinone (62% vs. 22%. Conclusion: Serial echocardiography provided crucial data for early recognition of septic myocardial dysfunction and hypovolemia that was not apparent on clinical assessment, allowing a timely management and resulting in shock reversal time reduction among children with septic shock.

  3. Riboflavin protects mice against liposaccharide-induced shock through expression of heat shock protein 25

    Science.gov (United States)

    Riboflavin (vitamin B2) is a water-soluble vitamin essential for normal cellular functions, growth and development. The study was aimed at investigating the effects of vitamin B2 on the survival rate, and expressions of tissue heat shock protein 25 (HSP25) and heat shock factor 1 (HSF1) in mice und...

  4. PARTICLE ACCELERATION AT THE HELIOSPHERIC TERMINATION SHOCK WITH A STOCHASTIC SHOCK OBLIQUITY APPROACH

    International Nuclear Information System (INIS)

    Arthur, Aaron D.; Le Roux, Jakobus A.

    2013-01-01

    Observations by the plasma and magnetic field instruments on board the Voyager 2 spacecraft suggest that the termination shock is weak with a compression ratio of ∼2. However, this is contrary to the observations of accelerated particle spectra at the termination shock, where standard diffusive shock acceleration theory predicts a compression ratio closer to ∼2.9. Using our focused transport model, we investigate pickup proton acceleration at a stationary spherical termination shock with a moderately strong compression ratio of 2.8 to include both the subshock and precursor. We show that for the particle energies observed by the Voyager 2 Low Energy Charged Particle (LECP) instrument, pickup protons will have effective length scales of diffusion that are larger than the combined subshock and precursor termination shock structure observed. As a result, the particles will experience a total effective termination shock compression ratio that is larger than values inferred by the plasma and magnetic field instruments for the subshock and similar to the value predicted by diffusive shock acceleration theory. Furthermore, using a stochastically varying magnetic field angle, we are able to qualitatively reproduce the multiple power-law structure observed for the LECP spectra downstream of the termination shock

  5. A shock surface geometry - The February 15-16, 1967, event. [solar flare associated interplanetary shock

    Science.gov (United States)

    Lepping, R. P.; Chao, J. K.

    1976-01-01

    An estimated shape is presented for the surface of the flare-associated interplanetary shock of February 15-16, 1967, as seen in the ecliptic-plane cross section. The estimate is based on observations by Explorer 33 and Pioneers 6 and 7. The estimated shock normal at the Explorer 33 position is obtained by a least-squares shock parameter-fitting procedure for that satellite's data; the shock normal at the Pioneer 7 position is found by using the magnetic coplanarity theorem and magnetic-field data. The average shock speed from the sun to each spacecraft is determined along with the local speed at Explorer 33 and the relations between these speeds and the position of the initiating solar flare. The Explorer 33 shock normal is found to be severely inclined and not typical of interplanetary shocks. It is shown that the curvature of the shock surface in the ecliptic plane near the earth-Pioneer 7 region is consistent with a radius of not more than 0.4 AU.

  6. Culture Shock: Information Packet for Developing Stress/Culture Shock Programs for Students in Overseas Schools.

    Science.gov (United States)

    Robinson, John

    This booklet, written for elementary teachers and counselors, provides information for a three-session stress and culture shock program for fifth and sixth grade students in overseas schools. Session 1 presents an introduction to the program, including discussion questions. Session 2 focuses on stress and culture shock through examples and…

  7. Holographic interferometric observation of shock wave focusing to extracorporeal shock wave lithotripsy

    Science.gov (United States)

    Takayama, Kazuyoshi; Obara, Tetsuro; Onodera, Osamu

    1991-04-01

    Underwater shock wave focusing is successfully applied to disintegrate and remove kidney stones or gallbladder stones without using surgical operations. This treatment is one of the most peaceful applications ofshock waves and is named as the Extracorporeal Shock Wave Lithotripsy. Ajoint research project is going on between the Institute ofFluid Science, Tohoku University and the School ofMedicine, Tohoku University. The paper describes a result of the fundamental research on the underwater shock wave focusing applied to the ESWL. Quantitatively to visualize the underwater shock waves, various optical flow visualization techniques were successfully used such as holographic interferometry, and shadowgraphs combined with Ima-Con high speed camera. Double exposure holographic interferometric observation revealed the mechanism of generation, propagation and focusing of underwater shock waves. The result of the present research was already used to manufacture a prototype machine and it has already been applied successfully to ESWL crinical treatments. However, despite of success in the clinical treatments, important fundamental questions still remain unsolved, i.e., effects of underwater shock wave focusing on tissue damage during the treatment. Model experiments were conducted to clarify mechanism of the tissue damage associated with the ESWL. Shock-bubble interactions were found responsible to the tissue damage during the ESWL treatment. In order to interprete experimental findings and to predict shock wave behavior and high pressures, a numerical simulation was carried. The numerical results agreed with the experiments.

  8. Diffusive Shock Acceleration and Turbulent Reconnection

    Science.gov (United States)

    Garrel, Christian; Vlahos, Loukas; Isliker, Heinz; Pisokas, Theophilos

    2018-05-01

    Diffusive Shock Acceleration (DSA) cannot efficiently accelerate particles without the presence of self-consistently generated or pre-existing strong turbulence (δB/B ˜ 1) in the vicinity of the shock. The problem we address in this article is: if large amplitude magnetic disturbances are present upstream and downstream of a shock then Turbulent Reconnection (TR) will set in and will participate not only in the elastic scattering of particles but also in their heating and acceleration. We demonstrate that large amplitude magnetic disturbances and Unstable Current Sheets (UCS), spontaneously formed in the strong turbulence in the vicinity of a shock, can accelerate particles as efficiently as DSA in large scale systems and on long time scales. We start our analysis with "elastic" scatterers upstream and downstream and estimate the energy distribution of particles escaping from the shock, recovering the well known results from the DSA theory. Next we analyze the additional interaction of the particles with active scatterers (magnetic disturbances and UCS) upstream and downstream of the shock. We show that the asymptotic energy distribution of the particles accelerated by DSA/TR has very similar characteristics with the one due to DSA alone, but the synergy of DSA with TR is much more efficient: The acceleration time is an order of magnitude shorter and the maximum energy reached two orders of magnitude higher. We claim that DSA is the dominant acceleration mechanism in a short period before TR is established, and then strong turbulence will dominate the heating and acceleration of the particles. In other words, the shock serves as the mechanism to set up a strongly turbulent environment, in which the acceleration mechanism will ultimately be the synergy of DSA and TR.

  9. On ion injection at quasiparallel shocks

    International Nuclear Information System (INIS)

    Scholer, M.; Kucharek, H.; Kato, C.

    2002-01-01

    A large number of numerical experiments has been performed in order to study the interaction of interstellar pickup protons and helium ions with quasiparallel collisionless shocks. The shocks are modeled by a one-dimensional hybrid simulation method which treats the ions as macroparticles and the electrons as a massless fluid. Solar wind alpha particles and pickup protons are included self-consistently. In addition, the particle splitting method is used for the solar wind ions so that the distribution function can be followed over more than 10 orders of magnitude. A large part of the pickup ion distribution is reflected; the reflection efficiency is very high, and can reach in cases where the pickup ion density is low as much as 50%-60%. The reflection efficiency is almost independent of magnetic field-shock normal angle. This indicates that magnetic mirroring is unimportant and does not lead to larger reflection efficiencies. The reflection efficiency of pickup protons rapidly decreases when the pickup ion density exceeds a few percent of the solar wind density. An addition of 25% pickup protons decreases the reflection coefficient for these ions to ∼10%. This represents the fact that a quasiparallel shock cannot be considered as being uncoupled from the upstream region: at high additions of pickup ions the shock structure is changed in such a way as to reflect less pickup ions. The intensity of diffuse ions upstream of a quasiparallel shock does not depend on the temperature of the core distribution. Within the framework of the present model even solar wind distributions with a hard power law tail do not produce higher intensities of diffuse ions. It is argued that this can be understood by the fact that the intrinsic self-consistency between the processes in the upstream region and at the shock transition determines the injection and reflection properties of the core solar wind distribution

  10. Is shock index associated with outcome in children with sepsis/septic shock?*.

    Science.gov (United States)

    Yasaka, Yuki; Khemani, Robinder G; Markovitz, Barry P

    2013-10-01

    To investigate the association between PICU shock index (the ratio of heart rate to systolic blood pressure) and PICU mortality in children with sepsis/septic shock. To explore cutoff values for shock index for ICU mortality, how change in shock index over the first 6 hours of ICU admission is associated with outcome, and how the use of vasoactive therapy may affect shock index and its association with outcome. Retrospective cohort. Single-center tertiary PICU. Five hundred forty-four children with the diagnosis of sepsis/septic shock. None. From January 2003 to December 2009, 544 children met International Pediatric Sepsis Consensus Conference of 2005 criteria for sepsis/septic shock. Overall mortality was 23.7%. Among all patients, hourly shock index was associated with mortality: odds ratio of ICU mortality at 0 hour, 1.08, 95% CI (1.04-1.12); odds ratio at 1 hour, 1.09 (1.04-1.13); odds ratio at 2 hours, 1.09 (1.05-1.13); and odds ratio at 6 hours, 1.11 (1.06-1.15). When stratified by age, early shock index was associated with mortality only in children 1-3 and more than or equal to 12 years old. Area under the receiver operating characteristic curve in age 1-3 and more than or equal to 12 years old for shock index at admission was 0.69 (95% CI, 0.58-0.80) and 0.62 (95% CI, 0.52-0.72) respectively, indicating a fair predictive marker. Although higher shock index was associated with increased risk of mortality, there was no particular cutoff value with adequate positive or negative likelihood ratios to identify mortality in any age group of children. The improvement of shock index in the first 6 hours of ICU admission was not associated with outcome when analyzed in all patients. However, among patients whose shock index were above the 50th percentile at ICU admission for each age group, improvement of shock index was associated with lower ICU mortality in children between 1-3 and more than or equal to 12 years old (p = 0.02 and p = 0.03, respectively). When

  11. On possible structures of normal ionizing shock waves in electromagnetic shock tubes

    International Nuclear Information System (INIS)

    Liberman, M.A.; Synakh, V.S.; Zakajdakhov, V.V.; Velikovich, A.L.

    1982-01-01

    The problem of possible structures of normal ionizing shock waves is studied. On the basis of the general theory of ionizing shock waves in magnetic fields, a similarity solution of the piston problem for an impenetrable piston and a magnetic piston is described and a numerical solution of the non-stationary piston problem is obtained. It is shown that precursor photo-ionization of the neutral gas by the radiation of the shock-heated gas is the dominant factor in shaping normal ionizing shock structures. In particular, it is shown that the strong overheating of atoms and ions in shock fronts is due to the tensor form of Ohm's law in the precursor region. (author)

  12. Multiple spacecraft observations of interplanetary shocks: four spacecraft determination of shock normals

    International Nuclear Information System (INIS)

    Russell, C.T.; Mellott, M.M.; Smith, E.J.; King, J.H.

    1983-01-01

    ISEE 1,2,3 IMP8, and Prognoz 7 observations of interplanetary shocks in 1978 and 1979 provide five instances where a single shock is observed by four spacecraft. These observations are used to determine best-fit normals for these five shocks. In addition to providing well-documented shocks for furture techniques. When the angle between upstream and downstream magnetic field is greater than 20, magnetic coplanarity can be an accurate single spacecraft method. However, no technique based solely on the magnetic measurements at one or multiple sites was universally accurate. Thus, we recommend using overdetermined shock normal solutions whenever possible, utilizing plasma measurements, separation vectors, and time delays together with magnetic constraints

  13. The MHD intermediate shock interaction with an intermediate wave: Are intermediate shocks physical?

    International Nuclear Information System (INIS)

    Wu, C.C.

    1988-01-01

    Contrary to the usual belief that MHD intermediate shocks are extraneous, the authors have recently shown by numerical solutions of dissipative MHD equations that intermediate shocks are admissible and can be formed through nonlinear steepening from a continuous wave. In this paper, he clarifies the differences between the conventional view and the results by studying the interaction of an MHD intermediate shock with an intermediate wave. The study reaffirms his results. In addition, the study shows that there exists a larger class of shocklike solutions in the time-dependent dissiaptive MHD equations than are given by the MHD Rankine-Hugoniot relations. it also suggests a mechanism for forming rotational discontinuities through the interaction of an intermediate shock with an intermediate wave. The results are of importance not only to the MHD shock theory but also to studies such as magnetic field reconnection models

  14. Application of Underwater Shock Wave Focusing to the Development of Extracorporeal Shock Wave Lithotripsy

    Science.gov (United States)

    Takayama, Kazuyoshi

    1993-05-01

    This paper describes a summary of a research project for the development of extracorporeal shock wave lithotripsy (ESWL), which has been carried out, under close collaboration between the Shock Wave Research Center of Tohoku University and the School of Medicine, Tohoku University. The ESWL is a noninvasive clinical treatment of disintegrating human calculi and one of the most peaceful applications of shock waves. Underwater spherical shock waves were generated by explosion of microexplosives. Characteristics of the underwater shock waves and of ultrasound focusing were studied by means of holographic interferometric flow visualization and polyvinyliden-difluoride (PVDF) pressure transducers. These focused pressures, when applied to clinical treatments, could effectively and noninvasively disintegrate urinary tract stones or gallbladder stones. However, despite clincal success, tissue damage occurs during ESWL treatments, and the possible mechanism of tissue damage is briefly described.

  15. Effects of Alfvénic Drift on Diffusive Shock Acceleration at Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2018-03-01

    Non-detection of γ-ray emission from galaxy clusters has challenged diffusive shock acceleration (DSA) of cosmic-ray (CR) protons at weak collisionless shocks that are expected to form in the intracluster medium. As an effort to address this problem, we here explore possible roles of Alfvén waves self-excited via resonant streaming instability during the CR acceleration at parallel shocks. The mean drift of Alfvén waves may either increase or decrease the scattering center compression ratio, depending on the postshock cross-helicity, leading to either flatter or steeper CR spectra. We first examine such effects at planar shocks, based on the transport of Alfvén waves in the small amplitude limit. For the shock parameters relevant to cluster shocks, Alfvénic drift flattens the CR spectrum slightly, resulting in a small increase of the CR acceleration efficiency, η. We then consider two additional, physically motivated cases: (1) postshock waves are isotropized via MHD and plasma processes across the shock transition, and (2) postshock waves contain only forward waves propagating along with the flow due to a possible gradient of CR pressure behind the shock. In these cases, Alfvénic drift could reduce η by as much as a factor of five for weak cluster shocks. For the canonical parameters adopted here, we suggest η ∼ 10‑4–10‑2 for shocks with sonic Mach number M s ≈ 2–3. The possible reduction of η may help ease the tension between non-detection of γ-rays from galaxy clusters and DSA predictions.

  16. A mechanical analysis of woodpecker drumming and its application to shock-absorbing systems

    International Nuclear Information System (INIS)

    Yoon, Sang-Hee; Park, Sungmin

    2011-01-01

    A woodpecker is known to drum the hard woody surface of a tree at a rate of 18 to 22 times per second with a deceleration of 1200 g, yet with no sign of blackout or brain damage. As a model in nature, a woodpecker is studied to find clues to develop a shock-absorbing system for micromachined devices. Its advanced shock-absorbing mechanism, which cannot be explained merely by allometric scaling, is analyzed in terms of endoskeletal structures. In this analysis, the head structures (beak, hyoid, spongy bone, and skull bone with cerebrospinal fluid) of the golden-fronted woodpecker, Melanerpes aurifrons, are explored with x-ray computed tomography images, and their shock-absorbing mechanism is analyzed with a mechanical vibration model and an empirical method. Based on these analyses, a new shock-absorbing system is designed to protect commercial micromachined devices from unwanted high-g and high-frequency mechanical excitations. The new shock-absorbing system consists of close-packed microglasses within two metal enclosures and a viscoelastic layer fastened by steel bolts, which are biologically inspired from a spongy bone contained within a skull bone encompassed with the hyoid of a woodpecker. In the experimental characterizations using a 60 mm smoothbore air-gun, this bio-inspired shock-absorbing system shows a failure rate of 0.7% for the commercial micromachined devices at 60 000 g, whereas a conventional hard-resin method yields a failure rate of 26.4%, thus verifying remarkable improvement in the g-force tolerance of the commercial micromachined devices.

  17. Bacterial survival following shock compression in the GigaPascal range

    Science.gov (United States)

    Hazael, Rachael; Fitzmaurice, Brianna C.; Foglia, Fabrizia; Appleby-Thomas, Gareth J.; McMillan, Paul F.

    2017-09-01

    The possibility that life can exist within previously unconsidered habitats is causing us to expand our understanding of potential planetary biospheres. Significant populations of living organisms have been identified at depths extending up to several km below the Earth's surface; whereas laboratory experiments have shown that microbial species can survive following exposure to GigaPascal (GPa) pressures. Understanding the degree to which simple organisms such as microbes survive such extreme pressurization under static compression conditions is being actively investigated. The survival of bacteria under dynamic shock compression is also of interest. Such studies are being partly driven to test the hypothesis of potential transport of biological organisms between planetary systems. Shock compression is also of interest for the potential modification and sterilization of foodstuffs and agricultural products. Here we report the survival of Shewanella oneidensis bacteria exposed to dynamic (shock) compression. The samples examined included: (a) a "wild type" (WT) strain and (b) a "pressure adapted" (PA) population obtained by culturing survivors from static compression experiments to 750 MPa. Following exposure to peak shock pressures of 1.5 and 2.5 GPa the proportion of survivors was established as the number of colony forming units (CFU) present after recovery to ambient conditions. The data were compared with previous results in which the same bacterial samples were exposed to static pressurization to the same pressures, for 15 minutes each. The results indicate that shock compression leads to survival of a significantly greater proportion of both WT and PA organisms. The significantly shorter duration of the pressure pulse during the shock experiments (2-3 μs) likely contributes to the increased survival of the microbial species. One reason for this can involve the crossover from deformable to rigid solid-like mechanical relaxational behavior that occurs for

  18. Shock interactions with heterogeneous energetic materials

    Science.gov (United States)

    Yarrington, Cole D.; Wixom, Ryan R.; Damm, David L.

    2018-03-01

    The complex physical phenomenon of shock wave interaction with material heterogeneities has significant importance and nevertheless remains little understood. In many materials, the observed macroscale response to shock loading is governed by characteristics of the microstructure. Yet, the majority of computational studies aimed at predicting phenomena affected by these processes, such as the initiation and propagation of detonation waves in explosives or shock propagation in geological materials, employ continuum material and reactive burn model treatment. In an effort to highlight the grain-scale processes that underlie the observable effects in an energetic system, a grain-scale model for hexanitrostilbene (HNS) has been developed. The measured microstructures were used to produce synthetic computational representations of the pore structure, and a density functional theory molecular dynamics derived equation of state (EOS) was used for the fully dense HNS matrix. The explicit inclusion of the microstructure along with a fully dense EOS resulted in close agreement with historical shock compression experiments. More recent experiments on the dynamic reaction threshold were also reproduced by inclusion of a global kinetics model. The complete model was shown to reproduce accurately the expected response of this heterogeneous material to shock loading. Mesoscale simulations were shown to provide a clear insight into the nature of threshold behavior and are a way to understand complex physical phenomena.

  19. Constitutive modeling of shock response of PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Reanyansky, Anatoly D [DSTO, AUSTRALIA; Bourne, Neil K [AWE, UK; Millett, Jeremy C F [AWE, UK

    2009-01-01

    The PTFE (polytetrafluoroethylene) material is complex and attracts attention of the shock physics researchers because it has amorphous and crystalline components. In turn, the crystalline component has four known phases with the high pressure transition to phase III. At the same time, as has been recently studied using spectrometry, the crystalline region is growing with load. Stress and velocity shock-wave profiles acquired recently with embedded gauges demonstrate feature that may be related to impedance mismatches between the regions subjected to some transitions resulting in density and modulus variations. We consider the above mentioned amorphous-to-crystalline transition and the high pressure Phase II-to-III transitions as possible candidates for the analysis. The present work utilizes a multi-phase rate sensitive model to describe shock response of the PTFE material. One-dimensional experimental shock wave profiles are compared with calculated profiles with the kinetics describing the transitions. The objective of this study is to understand the role of the various transitions in the shock response of PTFE.

  20. Advances in NIF Shock Timing Experiments

    Science.gov (United States)

    Robey, Harry

    2012-10-01

    Experiments are underway to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to multiple shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of all four shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector). Experiments are now routinely conducted in a mirrored keyhole geometry, which allows for simultaneous diagnosis of the shock timing at both the hohlraum pole and equator. Further modifications are being made to improve the surrogacy to ignition hohlraums by replacing the standard liquid deuterium (D2) capsule fill with a deuterium-tritium (DT) ice layer. These experiments will remove any possible surrogacy difference between D2 and DT as well as incorporate the physics of shock release from the ice layer, which is absent in current experiments. Experimental results and comparisons with numerical simulation are presented.

  1. Energy shocks and detecting influential industries

    International Nuclear Information System (INIS)

    Kang, Dongsuk; Lee, Duk Hee

    2017-01-01

    An industry's relationship of supply and demand with the energy sector can be a critical factor in the stability of its economic performance. Furthermore, the patterns of industry dependence on energy industries can be a major characteristic of entire industrial structure. This research evaluates industries' impact scores for their overall influence on other industries and vulnerability to supply and demand shocks from the energy sector. The study utilizes a sample of Korea's industrial input–output tables from 2010 to 2012. Using a chain of complementary methodologies, this study finds that among four clusters, energy, services, and raw materials are key members that can spread energy shocks to other industries. Therefore, governments need to prepare effective energy efficiency policies for these target industries. - Highlights: • We analyze an industry's impact score of its vulnerability to energy shock and inter-industrial effects. • We utilize the sample of input-output tables in Korea from 2010 to 2012. • We implement simulation, PCA, TOPSIS, cluster analysis about energy shock and industrial trades. • Subsectors of energy, services, raw material are subject to energy shock and influential to others. • These bridge industries can be targets that require policies for effective energy efficiency.

  2. Dopamine versus noradrenaline in septic shock

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2011-10-01

    Full Text Available BackgroundThe ‘Surviving Sepsis’ Campaign guidelines recommend theuse of dopamine or noradrenaline as the first vasopressor inseptic shock. However, information that guides clinicians inchoosing between dopamine and noradrenaline as the firstvasopressor in patients with septic shock is limited.ObjectiveThis article presents a review of the literature regarding theuse of dopamine versus noradrenaline in patients with septicshock.ResultsTwo randomised controlled trials (RCT and two largeprospective cohort studies were analysed. RCT data showeddopamine was associated with increased arrhythmic events.One cohort study found dopamine was associated with higher30-day mortality. The other cohort study found noradrenalinewas associated with higher 28-day mortality.DiscussionData on the use of dopamine versus noradrenaline in patientswith septic shock is limited. Following the recent SOAP IIstudy, there is now strong evidence that the use of dopaminein septic shock is associated with significantly morecardiovascular adverse events, compared tonoradrenaline.ConclusionNoradrenaline should be used as the initial vasopressor inseptic shock to avoid the arrhythmic events associatedwith dopamine.

  3. Thermal shock cracking of GSO single crystal

    International Nuclear Information System (INIS)

    Miyazaki, Noriyuki; Yamamoto, Kazunari; Tamura, Takaharu; Kurashige, Kazuhisa; Ishibashi, Hiroyuki; Susa, Kenzo

    1998-01-01

    The quantitative estimation of the failure stress of a gadolinium orthosilicate (Gd 2 SiO 5 , hereafter abbreviated as GSO) single crystal due to thermal shock was investigated. A cylindrical test specimen was heated in a silicone oil bath, then subjected to thermal shock by pouring room temperature silicone oil. Cracking occurred during cooling. The heat conduction analysis was performed to obtain temperature distribution in a GSO single crystal at cracking, using the surface temperatures measured in the thermal shock cracking test. Then the thermal stress was calculated using temperature profile of the test specimen obtained from the heat conduction analysis. It is found from the results of the thermal stress analysis and the observation of the cracking in test specimens that the thermal shock cracking occurs in a cleavage plane due to the stress normal to the plane. Three-point bending tests were also performed to examine the relationship between the critical stress for thermal shock cracking and the three-point bending strength obtained from small-sized test specimens. (author)

  4. Analytical model for fast-shock ignition

    International Nuclear Information System (INIS)

    Ghasemi, S. A.; Farahbod, A. H.; Sobhanian, S.

    2014-01-01

    A model and its improvements are introduced for a recently proposed approach to inertial confinement fusion, called fast-shock ignition (FSI). The analysis is based upon the gain models of fast ignition, shock ignition and considerations for the fast electrons penetration into the pre-compressed fuel to examine the formation of an effective central hot spot. Calculations of fast electrons penetration into the dense fuel show that if the initial electron kinetic energy is of the order ∼4.5 MeV, the electrons effectively reach the central part of the fuel. To evaluate more realistically the performance of FSI approach, we have used a quasi-two temperature electron energy distribution function of Strozzi (2012) and fast ignitor energy formula of Bellei (2013) that are consistent with 3D PIC simulations for different values of fast ignitor laser wavelength and coupling efficiency. The general advantages of fast-shock ignition in comparison with the shock ignition can be estimated to be better than 1.3 and it is seen that the best results can be obtained for the fuel mass around 1.5 mg, fast ignitor laser wavelength ∼0.3  micron and the shock ignitor energy weight factor about 0.25

  5. Shock analysis: Three useful new relations

    International Nuclear Information System (INIS)

    Smith, E.J.; Burton, M.E.

    1988-01-01

    Over the years a variety of methods for analyzing hydromagnetic shocks have been developed. The Rankine-Hugoniot relations on which the analyses are based are sufficiently complex and involve sufficiently large numbers of variables that in specific instances a decision must be made on how to proceed. The authors analyses have tended to emphasize the magnetic field (B) and velocity (V) as the starting point since they are typically the most accurately determined measurables. They authors have also tended to carry out the analysis in a reference frame aligned, and moving, with the shock. Three new relations have been derived which are generally useful. (1) The shock speed can be calculated from the upstream and downstream values of B and V independent of the shock normal or its direction relative to the upstream field. (2) An explicit relation is derived relating the angles between the jump in velocity, the shock normal, and the upstream field. (3) From the magnetic field and two-dimensional velocity measurements, which are frequently all that are available, it is possible to infer the third component of the upstream-downstream velocity jump

  6. Biological radioprotector

    International Nuclear Information System (INIS)

    Stefanescu, Ioan; Titescu, Gheorghe; Tamaian, Radu; Haulica, Ion; Bild, Walther

    2002-01-01

    According to the patent description, the biological radioprotector is deuterium depleted water, DDW, produced by vacuum distillation with an isotopic content lower than natural value. It appears as such or in a mixture with natural water and carbon dioxide. It can be used for preventing and reducing the ionizing radiation effects upon humans or animal organisms, exposed therapeutically, professionally or accidentally to radiation. The most significant advantage of using DDW as biological radioprotector results from its way of administration. Indeed no one of the radioprotectors currently used today can be orally administrated, what reduces the patients' compliance to prophylactic administrations. The biological radioprotector is an unnoxious product obtained from natural water, which can be administrated as food additive instead of drinking water. Dose modification factor is according to initial estimates around 1.9, what is a remarkable feature when one takes into account that the product is toxicity-free and side effect-free and can be administrated prophylactically as a food additive. A net radioprotective action of the deuterium depletion was evidenced experimentally in laboratory animals (rats) hydrated with DDW of 30 ppm D/(D+H) concentration as compared with normally hydrated control animals. Knowing the effects of irradiation and mechanisms of the acute radiation disease as well as the effects of administration of radiomimetic chemicals upon cellular lines of fast cell division, it appears that the effects of administrating DDW result from stimulation of the immunity system. In conclusion, the biological radioprotector DDW presents the following advantages: - it is obtained from natural products without toxicity; - it is easy to be administrated as a food additive, replacing the drinking water; - besides radioprotective effects, the product has also immunostimulative and antitumoral effects

  7. An Introduction to the Physics of Collisionless Shocks

    International Nuclear Information System (INIS)

    Russell, C.T.

    2005-01-01

    Collisionless shocks are important in astrophysical, heliospheric and magnetospheric settings. They deflect flows around obstacles; they heat the plasma, and they alter the properties of the flow as it intersects those obstacles. The physical processes occurring at collisionless shocks depend on the Mach number (strength) and beta (magnetic to thermal pressure) of the shocks and the direction of the magnetic field relative to the shock normal. Herein we review how the shock has been modeled in numerical simulations, the basic physical processes at work, including dissipation and thermalization, the electric potential drop at the shock, and the formation of the electron and ion foreshocks

  8. Magnetic field overshoots in the Venus blow shock

    International Nuclear Information System (INIS)

    Tatrallyay, M.; Luhmann, J.G.; Russell, C.T.

    1984-01-01

    An examination of Pioneer Venus Orbiter fluxgate magnetometer data has shown that magnetic field overshoots occur not only behind quasi-perpendicular bow shocks but also behind quasi-parallel shocks. Overshoots are assocciated only with supercritical shocks. Their amplitudes increase with increasing fast Mach number. Solar wind beta has a lesser effect. The thickness of the overshoot increases with decreasing Theta-BN. The thickness of apparent overshoots detected behind 4 strong fast interplanetary shocks (M greater than M/crit) is about 3 orders of magnitude larger. Multiple crossings of the Venus bow shock were observed mainly at turbulent shocks. Their occurence is not influenced by Theta-BN. 15 references

  9. Subcritical collisionless shock waves. [in earth space plasma

    Science.gov (United States)

    Mellott, M. M.

    1985-01-01

    The development history of theoretical accounts of low Mach number collisionless shock waves is related to recent observational advancements, with attention to weaker shocks in which shock steepening is limited by dispersion and/or anomalous resistivity and whose character is primarily determined by the dispersive properties of the ambient plasma. Attention has focused on nearly perpendicular shocks where dispersive scale lengths become small and the associated cross-field currents become strong enough to generate significant plasma wave turbulence. A number of oblique, low Mach number bow shocks have been studied on the basis of data from the ISEE dual spacecraft pair, allowing an accurate determination of shock scale lengths.

  10. Shock wave of vapor-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

    2008-01-01

    The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

  11. Structure of intermediate shocks and slow shocks in a magnetized plasma with heat conduction

    International Nuclear Information System (INIS)

    Tsai, C.L.; Wu, B.H.; Lee, L.C.

    2005-01-01

    The structure of slow shocks and intermediate shocks in the presence of a heat conduction parallel to the local magnetic field is simulated from the set of magnetohydrodynamic equations. This study is an extension of an earlier work [C. L. Tsai, R. H. Tsai, B. H. Wu, and L. C. Lee, Phys. Plasmas 9, 1185 (2002)], in which the effects of heat conduction are examined for the case that the tangential magnetic fields on the two side of initial current sheet are exactly antiparallel (B y =0). For the B y =0 case, a pair of slow shocks is formed as the result of evolution of the initial current sheet, and each slow shock consists of two parts: the isothermal main shock and the foreshock. In the present paper, cases with B y ≠0 are also considered, in which the evolution process leads to the presence of an additional pair of time-dependent intermediate shocks (TDISs). Across the main shock of the slow shock, jumps in plasma density, velocity, and magnetic field are significant, but the temperature is continuous. The plasma density downstream of the main shock decreases with time, while the downstream temperature increases with time, keeping the downstream pressure constant. The foreshock is featured by a smooth temperature variation and is formed due to the heat flow from downstream to upstream region. In contrast to the earlier study, the foreshock is found to reach a steady state with a constant width in the slow shock frame. In cases with B y ≠0, the plasma density and pressure increase and the magnetic field decreases across TDIS. The TDIS initially can be embedded in the slow shock's foreshock structure, and then moves out of the foreshock region. With an increasing B y , the propagation speed of foreshock leading edge tends to decrease and the foreshock reaches its steady state at an earlier time. Both the pressure and temperature downstreams of the main shock decrease with increasing B y . The results can be applied to the shock heating in the solar corona and

  12. Marine biology

    International Nuclear Information System (INIS)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

  13. Heat Shock Protein 90 Inhibitor (17-AAG) Induces Apoptosis and Decreases Cell Migration/Motility of Keloid Fibroblasts.

    Science.gov (United States)

    Yun, In Sik; Lee, Mi Hee; Rah, Dong Kyun; Lew, Dae Hyun; Park, Jong-Chul; Lee, Won Jai

    2015-07-01

    The regulation of apoptosis, proliferation, and migration of fibroblasts is altered in keloids. The 90-kDa heat shock protein (heat shock protein 90) is known to play a key role in such regulation. Therefore, the authors investigated whether the inhibition of heat shock protein 90 in keloid fibroblasts could induce apoptosis and attenuate keloid fibroblast proliferation and migration. The authors evaluated heat shock protein 90 expression in keloid tissues with immunohistochemistry. The authors used cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays and annexin V/propidium iodide staining for apoptosis, a wound healing model and cell tracking system to assess cell migration, and Akt Western blotting analysis in keloid fibroblasts after inhibition of heat shock protein 90 with 17-allylaminodemethoxygeldanamycin (17-AAG). The expression of heat shock protein 90 in keloid tissues was significantly increased compared with normal tissues. The 17-AAG-treated keloid fibroblasts showed significantly decreased proliferation, promotion of apoptosis, and decreased expression of Akt. Furthermore, a dose-dependent decrease in cell migration was noted after 17-AAG treatment of keloid fibroblasts. The 17-AAG-treated keloid fibroblasts had less directionality to the wound center and migrated a shorter distance. The authors confirmed that the inhibition of heat shock protein 90 in keloid fibroblasts could promote apoptosis and attenuate proliferation and migration of keloid fibroblasts. Therefore, the authors think that the inhibition of heat shock protein 90 is a key factor in the regulation of biological processes in keloids. With further preclinical study, the authors will be able to apply these results clinically for keloid treatment.

  14. Interplanetary shock phenomena beyond 1 AU

    International Nuclear Information System (INIS)

    Smith, E.J.

    1985-01-01

    Attention is given to spatial dependences exhibited by spacecraft measurements obtained between 1 and 30 AU, together with temporal variations occurring between solar activity cycle maxima and minima. At 1-3 AU radial distances, shocks develop in association with the corotating solar wind streams characterizing solar minimum and accelerate solar wind evolution with distance while heating the solar wind and generating waves and turbulence. At solar maximum, shocks are observed more frequently at 1 AU but still in association with transient solar events; acceleration leading to energetic storm particles is observed both within and beyond 1 AU. The superimposed effect of large numbers of intense shocks may be responsible for the solar cycle modulation of galactic cosmic rays. 77 references

  15. Economic Shocks and Subjective Well-Being

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Bjørnskov, Christian; Justesen, Mogens Kamp

    This paper examines how economic shocks affect individual well-being in developing countries. Using the case of a sudden and unanticipated currency devaluation in Botswana as a quasi-experiment, we examine how this monetary shock affects individuals’ evaluations of well-being. We do so by using...... micro-level survey data, which – incidentally – was collected in the days surrounding the devaluation. The chance occurrence of the devaluation during the time of the survey enables us to use pre-treatment respondents, surveyed before the devaluation, as approximate counterfactuals for post......-treatment respondents, surveyed after the devaluation. Our estimates show that the devaluation had a large and significantly negative effect on individuals’ evaluations of subjective well-being. These results suggest that macroeconomic shocks, such as unanticipated currency devaluations, may have significant short...

  16. Economic Shocks and Subjective Well-being

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Bjørnskov, Christian; Justesen, Mogens Kamp

    This paper examines how economic shocks affect individual well-being in developing countries. Using the case of a sudden and unanticipated currency devaluation in Botswana as a quasi-experiment, we examine how this monetary shock affects individuals’ evaluations of well-being. We do so by using...... micro-level survey data, which – incidentally – was collected in the days surrounding the devaluation. The chance occurrence of the devaluation during the time of the survey enables us to use pre-treatment respondents, surveyed before the devaluation, as approximate counterfactuals for post......-treatment respondents, surveyed after the devaluation. Our estimates show that the devaluation had a large and significantly negative effect on individuals’ evaluations of subjective well-being. These results suggest that macroeconomic shocks, such as unanticipated currency devaluations, may have significant short...

  17. Shock circle model for ejector performance evaluation

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Cai, Wenjian; Wen, Changyun; Li, Yanzhong

    2007-01-01

    In this paper, a novel shock circle model for the prediction of ejector performance at the critical mode operation is proposed. By introducing the 'shock circle' at the entrance of the constant area chamber, a 2D exponential expression for velocity distribution is adopted to approximate the viscosity flow near the ejector inner wall. The advantage of the 'shock circle' analysis is that the calculation of ejector performance is independent of the flows in the constant area chamber and diffuser. Consequently, the calculation is even simpler than many 1D modeling methods and can predict the performance of critical mode operation ejectors much more accurately. The effectiveness of the method is validated by two experimental results reported earlier. The proposed modeling method using two coefficients is shown to produce entrainment ratio, efficiency and coefficient of performance (COP) accurately and much closer to experimental results than those of 1D analysis methods

  18. International Shock-Wave Database: Current Status

    Science.gov (United States)

    Levashov, Pavel

    2013-06-01

    Shock-wave and related dynamic material response data serve for calibrating, validating, and improving material models over very broad regions of the pressure-temperature-density phase space. Since the middle of the 20th century vast amount of shock-wave experimental information has been obtained. To systemize it a number of compendiums of shock-wave data has been issued by LLNL, LANL (USA), CEA (France), IPCP and VNIIEF (Russia). In mid-90th the drawbacks of the paper handbooks became obvious, so the first version of the online shock-wave database appeared in 1997 (http://www.ficp.ac.ru/rusbank). It includes approximately 20000 experimental points on shock compression, adiabatic expansion, measurements of sound velocity behind the shock front and free-surface-velocity for more than 650 substances. This is still a useful tool for the shock-wave community, but it has a number of serious disadvantages which can't be easily eliminated: (i) very simple data format for points and references; (ii) minimalistic user interface for data addition; (iii) absence of history of changes; (iv) bad feedback from users. The new International Shock-Wave database (ISWdb) is intended to solve these and some other problems. The ISWdb project objectives are: (i) to develop a database on thermodynamic and mechanical properties of materials under conditions of shock-wave and other dynamic loadings, selected related quantities of interest, and the meta-data that describes the provenance of the measurements and material models; and (ii) to make this database available internationally through the Internet, in an interactive form. The development and operation of the ISWdb is guided by an advisory committee. The database will be installed on two mirrored web-servers, one in Russia and the other in USA (currently only one server is available). The database provides access to original experimental data on shock compression, non-shock dynamic loadings, isentropic expansion, measurements of sound

  19. Analysis of a cylindrical imploding shock wave

    International Nuclear Information System (INIS)

    Mishkin, E.A.; Fujimoto, Y.

    1978-01-01

    the self-similar solution of the gasdynamic equations of a strong cylindrical shock wave moving through an ideal gas, with γ = csub(p)/csub(v), is considered. These equations are greatly simplified following the transformation of the reduced velocity U 1 (xi) → U 1 = 1/2(γ + 1 ) (U + xi). The requirement of a single maximum pressure, dsub(xi)P = 0, leads to an analytical determination of the self-similarity exponent α(γ). For gases with γ = 2 + 3sup(1/2), this maximum ensues right at the shock front and the pressure distribution then decreases monotonically. The postulate of analyticity by Gelfand and Butler is shown to concur with the requirement dsub(xi)P 0. The saturated density of the gas left in the wake of the shock is computed and - U is shown to be the reduced velocity of sound at P = P sub(m). (author)

  20. Shock timing measurements in DT ice layers

    Science.gov (United States)

    Robey, H. F.; Celliers, P. M.; Moody, J. D.; Sater, J.; Parham, T.; Kozioziemski, B.; Dylla-Spears, R. J.; Ross, J. S.; Lepape, S.; Ralph, J. E.; Berzak Hopkins, L. F.; Kroll, J. J.; Yoxall, B. E.; Hamza, A. V.; Boehly, T. R.; Nikroo, A.; Landen, O. L.; Edwards, M. J.

    2013-10-01

    Shock timing experiments on the National Ignition Facility (NIF) are routinely conducted using the keyhole target geometry, in which the strength and timing of multiple shocks are measured in a liquid-deuterium (D2) filled capsule interior. These targets have recently been modified to improve the surrogacy to ignition implosions by replacing the standard, continuous liquid D2 capsule fill with a deuterium-tritium (DT) ice layer with a central DT gas fill. These experiments remove any possible material surrogacy difference between D2 and DT as well as incorporating the physics of multiple shock release and recompression events from an ice layer of finite thickness, an effect that is absent in the liquid-filled targets. Experimental results and comparisons with numerical simulation are presented. Prepared by LLNL under Contract DE-AC52-07NA27344.

  1. Uniform shock waves in disordered granular matter.

    Science.gov (United States)

    Gómez, Leopoldo R; Turner, Ari M; Vitelli, Vincenzo

    2012-10-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates continuously decreases as the confining pressure decreases, completely vanishing at the jamming-unjamming transition. This anomalous behavior suggests that the transport of energy at low pressures should not be dominated by phonons. In this work we use simulations and theory to show how the response of granular systems becomes increasingly nonlinear as pressure decreases. In the low-pressure regime the elastic energy is found to be mainly transported through nonlinear waves and shocks. We numerically characterize the propagation speed, shape, and stability of these shocks and model the dependence of the shock speed on pressure and impact intensity by a simple analytical approach.

  2. Shock Transmission and Fatigue in Human Running.

    Science.gov (United States)

    Verbitsky, Oleg; Mizrahi, Joseph; Voloshin, Arkady; Treiger, July; Isakov, Eli

    1998-08-01

    The goal of this research was to analyze the effects of fatigue on the shock waves generated by foot strike. Twenty-two subjects were instrumented with an externally attached, lightweight accelerometer placed over the tibial tuberosity. The subjects ran on a treadmill for 30 min at a speed near their anaerobic threshold. Fatigue was established when the end-tidal CO 2 pressure decreased. The results indicated that approximately half of the subjects reached the fatigue state toward the end of the test. Whenever fatigue occurred, the peak acceleration was found to increase. It was thus concluded that there is a clear association between fatigue and increased heel strike-induced shock waves. These results have a significant implication for the etiology of running injuries, since shock wave attenuation has been previously reported to play an important role in preventing such injuries.

  3. Control groups in recent septic shock trials

    DEFF Research Database (Denmark)

    Pettilä, Ville; Hjortrup, Peter B; Jakob, Stephan M

    2016-01-01

    PURPOSE: The interpretation of septic shock trial data is profoundly affected by patients, control intervention, co-interventions and selected outcome measures. We evaluated the reporting of control groups in recent septic shock trials. METHODS: We searched for original articles presenting......, and mortality outcomes, and calculated a data completeness score to provide an overall view of quality of reporting. RESULTS: A total of 24 RCTs were included (mean n = 287 patients and 71 % of eligible patients were randomized). Of the 24 studies, 14 (58 %) presented baseline data on vasopressors and 58...... % the proportion of patients with elevated lactate values. Five studies (21 %) provided data to estimate the proportion of septic shock patients fulfilling the Sepsis-3 definition. The mean data completeness score was 19 out of 36 (range 8-32). Of 18 predefined control group characteristics, a mean of 8 (range 2...

  4. Shock Tube as an Impulsive Application Device

    Directory of Open Access Journals (Sweden)

    Soumya Ranjan Nanda

    2017-01-01

    Full Text Available Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.

  5. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book is the second of several volumes on solids in the Shock Wave Science and Technology Reference Library. These volumes are primarily concerned with high-pressure shock waves in solid media, including detonation and high-velocity impact and penetration events. Of the four extensive chapters in this volume, the first two describe the reactive behavior of condensed phase explosives, - Condensed-Phase Explosives: Shock Initiation and Detonation Phenomena (SA Sheffield and R Engelke) - First Principles Molecular Simulations of Energetic Materials at High-Pressures (F Zhang, S Alavi, and TK Woo), and the remaining two discuss the inert, mechanical response of solid materials. - Combined Compression and Shear Plane Waves (ZP Tang and JB Aidun), and - Dynamic Fragmentation of Solids (D Grady). All chapters are each self-contained, and can be read independently of each other. They offer a timely reference, for beginners as well as professional scientists and engineers, on the foundations of detonation phenomen...

  6. Structural Biology Fact Sheet

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Structural Biology Structural Biology Tagline (Optional) Middle/Main Content Area PDF Version (688 KB) Other Fact Sheets What is structural biology? Structural biology is the study of how biological ...

  7. Shock waves in P-bar target

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhijing; Anderson, K.

    1991-11-01

    The deposition of large amount of beam energy in short time will cause high temperature and pressure in the center of P-bar Target, and this disturbance will propagate outwards as a shock wave. Shock wave induced material changes which are of our concern include void growth and accompanying density decrease which will decrease antiproton yield, and crack formation and fracture as was observed in tungsten target which will destroy the integrity of the target. Our objective is to analyze the shock wave behavior in the target, optimize its design so that the destructive effects of shock wave can be minimized, the integrity of the target can be maintained, and a reasonably high yield of antiproton production can be achieved. In this report we put together some results of our analysis of a cylindrical copper target. We hope that it will provide a general overview of the shock wave phenomena in the target, establish a basis for further research, and facilitate the target design. First, energy deposition data are analyzed, and it is justified that as an approximation, the problem can be treated as axi-symmetric. The average data therefore are used as energy profile, however, the maximum energy deposition are still used as the peak value. Next some basic estimations are made as to what temperature and pressure can reach at present level of energy deposition. Then some characteristics of wave propagation in a thermal shock loaded solid are illustrated with a one-dimensional model. Since there is no analytical solution available for cylindrical geometry, our understanding of the problem relies on numerical model, which are performed via finite element package ANSYS. results of numerical analysis are summarized, sources of potential danger are identified, and design ideas to minimize the damage are proposed.

  8. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  9. Shock waves in P-bar target

    International Nuclear Information System (INIS)

    Tang, Zhijing; Anderson, K.

    1991-11-01

    The deposition of large amount of beam energy in short time will cause high temperature and pressure in the center of P-bar Target, and this disturbance will propagate outwards as a shock wave. Shock wave induced material changes which are of our concern include void growth and accompanying density decrease which will decrease antiproton yield, and crack formation and fracture as was observed in tungsten target which will destroy the integrity of the target. Our objective is to analyze the shock wave behavior in the target, optimize its design so that the destructive effects of shock wave can be minimized, the integrity of the target can be maintained, and a reasonably high yield of antiproton production can be achieved. In this report we put together some results of our analysis of a cylindrical copper target. We hope that it will provide a general overview of the shock wave phenomena in the target, establish a basis for further research, and facilitate the target design. First, energy deposition data are analyzed, and it is justified that as an approximation, the problem can be treated as axi-symmetric. The average data therefore are used as energy profile, however, the maximum energy deposition are still used as the peak value. Next some basic estimations are made as to what temperature and pressure can reach at present level of energy deposition. Then some characteristics of wave propagation in a thermal shock loaded solid are illustrated with a one-dimensional model. Since there is no analytical solution available for cylindrical geometry, our understanding of the problem relies on numerical model, which are performed via finite element package ANSYS. results of numerical analysis are summarized, sources of potential danger are identified, and design ideas to minimize the damage are proposed

  10. Spherical strong-shock generation for shock-ignition inertial fusion

    Energy Technology Data Exchange (ETDEWEB)

    Theobald, W.; Seka, W.; Lafon, M.; Anderson, K. S.; Hohenberger, M.; Marshall, F. J.; Michel, D. T.; Solodov, A. A.; Stoeckl, C.; Edgell, D. H.; Yaakobi, B.; Shvydky, A. [Laboratory for Laser Energetics and Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Nora, R.; Betti, R. [Laboratory for Laser Energetics and Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Department of Mechanical Engineering and Department of Physics, University of Rochester, Rochester, New York 14623 (United States); Casner, A.; Reverdin, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Ribeyre, X.; Vallet, A. [Université de Bordeaux-CNRS-CEA, CELIA (Centre Lasers Intenses et Applications) UMR 5107 F-33400 Talence (France); Peebles, J.; Beg, F. N. [University of California, San Diego, La Jolla, California 92093 (United States); and others

    2015-05-15

    Recent experiments on the Laboratory for Laser Energetics' OMEGA laser have been carried out to produce strong shocks in solid spherical targets with direct laser illumination. The shocks are launched at pressures of several hundred Mbars and reach Gbar upon convergence. The results are relevant to the validation of the shock-ignition scheme and to the development of an OMEGA experimental platform to study material properties at Gbar pressures. The experiments investigate the strength of the ablation pressure and the hot-electron production at incident laser intensities of ∼2 to 6 × 10{sup 15 }W/cm{sup 2} and demonstrate ablation pressures exceeding 300 Mbar, which is crucial to developing a shock-ignition target design for the National Ignition Facility. The timing of the x-ray flash from shock convergence in the center of the solid plastic target is used to infer the ablation and shock pressures. Laser–plasma instabilities produce hot-electrons with a moderate temperature (<100 keV). The instantaneous conversion efficiencies of laser power into hot-electron power reached up to ∼15% in the intensity spike. The large amount of hot electrons is correlated with an earlier x-ray flash and a strong increase in its magnitude. This suggests that hot electrons contribute to the augmentation of the shock strength.

  11. THE ROLE OF PICKUP IONS ON THE STRUCTURE OF THE VENUSIAN BOW SHOCK AND ITS IMPLICATIONS FOR THE TERMINATION SHOCK

    International Nuclear Information System (INIS)

    Lu Quanming; Shan Lican; Zhang Tielong; Wu Mingyu; Wang Shui; Zank, Gary P.; Yang Zhongwei; Du Aimin

    2013-01-01

    The recent crossing of the termination shock by Voyager 2 has demonstrated the important role of pickup ions (PUIs) in the physics of collisionless shocks. The Venus Express (VEX) spacecraft orbits Venus in a 24 hr elliptical orbit that crosses the bow shock twice a day. VEX provides a unique opportunity to investigate the role of PUIs on the structure of collisionless shocks more generally. Using VEX observations, we find that the strength of the Venusian bow shock is weaker when solar activity is strong. We demonstrate that this surprising anti-correlation is due to PUIs mediating the Venusian bow shock

  12. em>In vivoem> biological response to extracorporeal shockwave therapy in human tendinopathy

    DEFF Research Database (Denmark)

    Waugh, C. M.; Morrissey, D.; Jones, E.

    2015-01-01

    Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment for chronic tendinopathies, however little is known about the in-vivo biological mechanisms of ESWT. Using microdialysis, we examined the real-time biological response of healthy and pathological tendons to ESWT. A single session...

  13. Free Piston Double Diaphragm Shock Tube

    OpenAIRE

    OGURA, Eiji; FUNABIKI, Katsushi; SATO, Shunichi; ABE, Takashi; 小倉, 栄二; 船曳, 勝之; 佐藤, 俊逸; 安部, 隆士

    1997-01-01

    A free piston double diaphragm shock tube was newly developed for generation of high Mach number shock wave. Its characteristics was investigated for various operation parameters; such as a strength of the diaphragm at the end of the comparession tube, an initial pressure of low pressure tube, an initial pressure of medium pressure tube and the volume of compression tube. Under the restriction of fixed pressures for the driver high pressure tube (32×10^5Pa) and the low pressure tube (40Pa) in...

  14. Apparatus for reducing shock and overpressure

    Science.gov (United States)

    Walter, C.E.

    1975-01-28

    An apparatus for reducing shock and overpressure is particularly useful in connection with the sequential detonation of a series of nuclear explosives under ground. A coupling and decoupling arrangement between adjacent nuclear explosives in the tubing string utilized to emplace the explosives is able to support lower elements on the string but yields in a manner which absorbs energy when subjected to the shock wave produced upon detonation of one of the explosives. Overpressure is accomodated by an arrangement in the string which provides an additional space into which the pressurized material can expand at a predetermined overpressure. (10 claims)

  15. Electron Shock Ignition of Inertial Fusion Targets

    International Nuclear Information System (INIS)

    Shang, W. L.; Betti, R.; Hu, S. X.; Woo, K.; Hao, L.

    2017-01-01

    Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2 .

  16. Shock wave interactions with detonable clouds

    International Nuclear Information System (INIS)

    Ripley, R.C.; Josey, T.; Donahue, L.; Whitehouse, D.R.

    2004-01-01

    This paper presents results from the numerical simulation of compressible multi-species gases in an unstructured mesh CFD code called Chinook. Multiple species gases are significant to a wide range of CFD applications that involve chemical reactions, in particular detonation. The purpose of this paper is to investigate the interaction of shock waves with localized regions of reactive and non-reactive gas species. Test cases are chosen to highlight shock reflection and acceleration through combustion products resulting from the detonation of an explosive charge, and detonation wave propagation through a fuel-air cloud. Computations are performed in a 2D axi-symmetric framework. (author)

  17. Ground Shock Effects from Accidental Explosions

    Science.gov (United States)

    1976-11-01

    1,200 P0 A = V P cp 8 Horizontal Dh = Dv tannin " 1 (cp/U)] Vh = Vv tan [sin" 1 (cp/U)] \\ - \\ tanfainŕ (cp/U)] For tan sin (c /U...explosive are not included in the present analysis . This effect will limit the credibility of the direct- induced ground shock predictions, but if the... analysis . Dr. D. R. Richmond of Lovelace Foundation provided data on human shock tolerances. 26 REFERENCES 1. "Structures to Resist the Effects of

  18. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  19. Monetary Policy Shocks and Portfolio Choice

    OpenAIRE

    Fratzscher, Marcel; Saborowski, Christian; Straub, Roland

    2010-01-01

    The paper shows that monetary policy shocks exert a substantial effect on the size and composition of capital flows and the trade balance for the United States, with a 100 basis point easing raising net capital inflows and lowering the trade balance by 1% of GDP, and explaining about 20-25% of their time variation. Monetary policy easing causes positive returns to both equities and bonds. Yet such a monetary policy easing shock also induces a shift in portfolio composition out of equities and...

  20. Temperature measurement of tin under shock compression

    International Nuclear Information System (INIS)

    Hereil, Pierre-Louis; Mabire, Catherine

    2002-01-01

    The results of pyrometric measurements performed at the interface of a tin target with a LiF window material are presented for stresses ranging from 38 to 55 GPa. The purpose of the study is to analyze the part of the interface in the temperature measurement by a multi-channel pyrometric device. The results show that the glue used at target/window interface remains transparent under shock. The values of temperature measured at the tin/LiF interface are consistent with the behavior of tin under shock

  1. Materials and structures under shock and impact

    CERN Document Server

    Bailly, Patrice

    2013-01-01

    In risk studies, engineers often have to consider the consequences of an accident leading to a shock on a construction. This can concern the impact of a ground vehicle or aircraft, or the effects of an explosion on an industrial site.This book presents a didactic approach starting with the theoretical elements of the mechanics of materials and structures, in order to develop their applications in the cases of shocks and impacts. The latter are studied on a local scale at first. They lead to stresses and strains in the form of waves propagating through the material, this movement then extending

  2. Multiple shocks, coping and welfare consequences: natural disasters and health shocks in the Indian Sundarbans.

    Science.gov (United States)

    Mazumdar, Sumit; Mazumdar, Papiya Guha; Kanjilal, Barun; Singh, Prashant Kumar

    2014-01-01

    Based on a household survey in Indian Sundarbans hit by tropical cyclone Aila in May 2009, this study tests for evidence and argues that health and climatic shocks are essentially linked forming a continuum and with exposure to a marginal one, coping mechanisms and welfare outcomes triggered in the response is significantly affected. The data for this study is based on a cross-sectional household survey carried out during June 2010. The survey was aimed to assess the impact of cyclone Aila on households and consequent coping mechanisms in three of the worst-affected blocks (a sub-district administrative unit), viz. Hingalganj, Gosaba and Patharpratima. The survey covered 809 individuals from 179 households, cross cutting age and gender. A separate module on health-seeking behaviour serves as the information source of health shocks defined as illness episodes (ambulatory or hospitalized) experienced by household members. Finding reveals that over half of the households (54%) consider that Aila has dealt a high, damaging impact on their household assets. Result further shows deterioration of health status in the period following the incidence of Aila. Finding suggests having suffered multiple shocks increases the number of adverse welfare outcomes by 55%. Whereas, suffering either from the climatic shock (33%) or the health shock (25%) alone increases such risks by a much lesser extent. The multiple-shock households face a significantly higher degree of difficulty to finance expenses arising out of health shocks, as opposed to their counterparts facing only the health shock. Further, these households are more likely to finance the expenses through informal loans and credit from acquaintances or moneylenders. This paper presented empirical evidence on how natural and health shocks mutually reinforce their resultant impact, making coping increasingly difficult and present significant risks of welfare loss, having short as well as long-run development manifestations.

  3. Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

    Science.gov (United States)

    Bell, Mary S.; Zolensky, Michael E.

    2011-01-01

    The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

  4. The Septic Shock 3.0 Definition and Trials: A Vasopressin and Septic Shock Trial Experience.

    Science.gov (United States)

    Russell, James A; Lee, Terry; Singer, Joel; Boyd, John H; Walley, Keith R

    2017-06-01

    The Septic Shock 3.0 definition could alter treatment comparisons in randomized controlled trials in septic shock. Our first hypothesis was that the vasopressin versus norepinephrine comparison and 28-day mortality of patients with Septic Shock 3.0 definition (lactate > 2 mmol/L) differ from vasopressin versus norepinephrine and mortality in Vasopressin and Septic Shock Trial. Our second hypothesis was that there are differences in plasma cytokine levels in Vasopressin and Septic Shock Trial for lactate less than or equal to 2 versus greater than 2 mmol/L. Retrospective analysis of randomized controlled trial. Multicenter ICUs. We compared vasopressin-to-norepinephrine group 28- and 90-day mortality in Vasopressin and Septic Shock Trial in lactate subgroups. We measured 39 cytokines to compare patients with lactate less than or equal to 2 versus greater than 2 mmol/L. Patients with septic shock with lactate greater than 2 mmol/L or less than or equal to 2 mmol/L, randomized to vasopressin or norepinephrine. Concealed vasopressin (0.03 U/min.) or norepinephrine infusions. The Septic Shock 3.0 definition would have decreased sample size by about half. The 28- and 90-day mortality rates were 10-12 % higher than the original Vasopressin and Septic Shock Trial mortality. There was a significantly (p = 0.028) lower mortality with vasopressin versus norepinephrine in lactate less than or equal to 2 mmol/L but no difference between treatment groups in lactate greater than 2 mmol/L. Nearly all cytokine levels were significantly higher in patients with lactate greater than 2 versus less than or equal to 2 mmol/L. The Septic Shock 3.0 definition decreased sample size by half and increased 28-day mortality rates by about 10%. Vasopressin lowered mortality versus norepinephrine if lactate was less than or equal to 2 mmol/L. Patients had higher plasma cytokines in lactate greater than 2 versus less than or equal to 2 mmol/L, a brisker cytokine response to infection. The Septic

  5. IDENTIFICATION AND DESCRIPTION OF A NOVEL MURINE MODEL FOR POLYTRAUMA AND SHOCK

    Science.gov (United States)

    Gentile, Lori F; Nacionales, Dina C; Cuenca, Alex G; Armbruster, Michael; Ungaro, Ricardo F; Abouhamze, Amer S; Lopez, Cecelia; Baker, Henry V; Moore, Frederick A; Ang, Darwin N; Efron, Philip A

    2013-01-01

    Objective To develop a novel polytrauma model that better recapitulates the immunological response of the severely injured patient by combining long-bone fracture, muscle tissue damage and cecectomy with hemorrhagic shock, resulting in an equivalent Injury Severity Score of greater than 15. We compared this new polytrauma/shock model to historically-used murine trauma-hemorrhage models. Design Pre-clinical controlled in vivo laboratory study. Setting Laboratory of Inflammation Biology and Surgical Science. Subjects 6–10 wk old C57BL/6 (B6) mice Interventions Mice underwent 90 minutes of shock (MAP 30 mmHg) and resuscitation via femoral artery cannulation followed by either laparotomy (TH), laparotomy with femur fracture (H+FFx), or laparotomy with cecetomy and femur fracture with muscle tissue damage (PT). Mice were euthanized at two hours, one day and three days post injury. Measurements and Main Results The spleen, bone marrow, blood, and serum were collected from mice for analysis at the above time points. None of the models were lethal. Mice undergoing PT exhibited a more robust inflammatory response with significant elevations in cytokine/chemokine concentrations when compared to traditional models. PT was the only model to induce neutrophilia (Ly6G+CD11b+ cells) on days 1 and 3 (ppolytrauma model better replicates the human leukocyte, cytokine, and overall inflammatory response following injury and hemorrhagic shock. PMID:23399937

  6. Free radical production by high energy shock waves--comparison with ionizing irradiation.

    Science.gov (United States)

    Morgan, T R; Laudone, V P; Heston, W D; Zeitz, L; Fair, W R

    1988-01-01

    Fricke chemical dosimetry is used as an indirect measure of the free radical production of ionizing irradiation. We adapted the Fricke ferrous sulfate radiation dosimeter to examine the chemical effects of high energy shock waves. Significant free radical production was documented. The reaction was dose dependent, predictably increased by acoustic impedance, but curvilinear. A thousand shocks at 18 kilovolts induced the same free radical oxidation as 1100 rad cobalt-60 gamma ionizing irradiation, increasing to 2900 rad in the presence of an air-fluid zone of acoustic impedance. The biological effect of these free radicals was compared to that of cobalt-60 ionizing irradiation by measuring the affect on Chinese hamster cells by clonogenic assay. While cobalt-60 irradiation produced a marked decrease in clonogenic survivors, little effect was noted with high energy shock waves. This suggested that the chemical effects produced by shock waves were either absent or attenuated in the cells, or were inherently less toxic than those of ionizing irradiation.

  7. Biology Branch

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, W F

    1974-12-31

    Progress is reported on the following studies in biochemistry and molecular biology: study of long pyrimidine polynucleotides in DNA; isolation of thymine dimers from Schizosaccharomyces pombe; thermal stability of high molecular weight RNA; nucleases of Micrococcus radiodurans; effect of ionizing radiation on M. radiodurans cell walls and cell membranes; chemical modification of nucleotides; exonucleases of M. radiodurans; and enzymatic basis of repair of radioinduced damage in M. radiodurans. Genetics, development, and population studies include repair pathways and mutation induction in yeast; induction of pure mutant clones in yeast; radiosensitivity of bacteriophage T4; polyacrylamide gel electrophoresis of bacteriophage T4; radiation genetics of Dahibominus; and radiation studies on bitting flies. (HLW)

  8. Collisionless shocks in space plasmas structure and accelerated particles

    CERN Document Server

    Burgess, David

    2015-01-01

    Shock waves are an important feature of solar system plasmas, from the solar corona out to the edge of the heliosphere. This engaging introduction to collisionless shocks in space plasmas presents a comprehensive review of the physics governing different types of shocks and processes of particle acceleration, from fundamental principles to current research. Motivated by observations of planetary bow shocks, interplanetary shocks and the solar wind termination shock, it emphasises the physical theory underlying these shock waves. Readers will develop an understanding of the complex interplay between particle dynamics and the electric and magnetic fields that explains the observations of in situ spacecraft. Written by renowned experts in the field, this up-to-date text is the ideal companion for both graduate students new to heliospheric physics and researchers in astrophysics who wish to apply the lessons of solar system shocks to different astrophysical environments.

  9. Social Protection and Vulnerability to Climate Shocks: a Panel Data ...

    African Journals Online (AJOL)

    ' autonomous adaptation by reducing vulnerability to climatic shocks. This paper examines the role of the Productive Safety Net Program in reducing vulnerability to climate related shocks and its impacts on autonomous adaptation strategies ...

  10. Collisionless Weibel shocks: Full formation mechanism and timing

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain); Stockem, A. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Narayan, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51 Cambridge, Massachusetts 02138 (United States); Silva, L. O. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal)

    2014-07-15

    Collisionless shocks in plasmas play an important role in space physics (Earth's bow shock) and astrophysics (supernova remnants, relativistic jets, gamma-ray bursts, high energy cosmic rays). While the formation of a fluid shock through the steepening of a large amplitude sound wave has been understood for long, there is currently no detailed picture of the mechanism responsible for the formation of a collisionless shock. We unravel the physical mechanism at work and show that an electromagnetic Weibel shock always forms when two relativistic collisionless, initially unmagnetized, plasma shells encounter. The predicted shock formation time is in good agreement with 2D and 3D particle-in-cell simulations of counterstreaming pair plasmas. By predicting the shock formation time, experimental setups aiming at producing such shocks can be optimised to favourable conditions.

  11. Shock waves in collective field theories for many particle systems

    Energy Technology Data Exchange (ETDEWEB)

    Oki, F; Saito, T [Kyoto Prefectural Univ. of Medicine (Japan); Shigemoto, K

    1980-10-01

    We find shock wave solutions to collective field equations for quantum mechanical many particle system. Importance of the existence of a ''tension'' working on the surface of the shock-wave front is pointed out.

  12. The Shock Wave in the ionosphere during an Earthquake

    Directory of Open Access Journals (Sweden)

    Kuznetsov Vladimir

    2016-01-01

    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud.

  13. Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

    KAUST Repository

    Javed, Tamour; Badra, J.; Jaasim, Mohammed; Es-sebbar, Et-touhami; Labastida, M.F.; Chung, Suk-Ho; Im, Hong G.; Farooq, Aamir

    2016-01-01

    Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times

  14. Ultrafast dynamic ellipsometry and spectroscopies of laser shocked materials

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

    2010-01-01

    Ultrafast ellipsometry and transient absorption spectroscopies are used to measure material dynamics under extreme conditions of temperature, pressure, and volumetric compression induced by shock wave loading with a chirped, spectrally clipped shock drive pulse.

  15. Cosmic ray acceleration by large scale galactic shocks

    International Nuclear Information System (INIS)

    Cesarsky, C.J.; Lagage, P.O.

    1987-01-01

    The mechanism of diffusive shock acceleration may account for the existence of galactic cosmic rays detailed application to stellar wind shocks and especially to supernova shocks have been developed. Existing models can usually deal with the energetics or the spectral slope, but the observed energy range of cosmic rays is not explained. Therefore it seems worthwhile to examine the effect that large scale, long-lived galactic shocks may have on galactic cosmic rays, in the frame of the diffusive shock acceleration mechanism. Large scale fast shocks can only be expected to exist in the galactic halo. We consider three situations where they may arise: expansion of a supernova shock in the halo, galactic wind, galactic infall; and discuss the possible existence of these shocks and their role in accelerating cosmic rays

  16. Loss of shear strength in polycrystalline tungsten under shock compression

    International Nuclear Information System (INIS)

    Dandekar, D.P.

    1976-01-01

    A reexamination of existing data on shock compression of polycrystalline tungsten at room temperature indicates that tungsten may be an exception to the common belief that metals do not behave like elastic-isotropic solids under shock compression

  17. Influence of interface scattering on shock waves in heterogeneous solids

    International Nuclear Information System (INIS)

    Zhuang Shiming; Ravichandran, Guruswami; Grady, Dennis E.

    2002-01-01

    In heterogeneous media, the scattering due to interfaces between dissimilar materials play an important role in shock wave dissipation and dispersion. In this work the influence of interface scattering effect on shock waves was studied by impacting flyer plates onto periodically layered polycarbonate/6061 aluminum, polycarbonate/304 stainless steel and polycarbonate/glass composites. The experimental results (using VISAR and stress gauges) indicate that the rise time of the shock front decreases with increasing shock strength, and increases with increasing mechanical impedance mismatch between layers; the strain rate at the shock front increases by about the square of the shock stress. Experimental and numerical results also show that due to interface scattering effect the shock wave velocity in periodically layered composites decreases. In some cases the shock velocity of a layered heterogeneous composite can be lower than that of either of its components

  18. State of the art extracorporeal shock wave lithotripsy

    Energy Technology Data Exchange (ETDEWEB)

    Kandel, L.B. (State Univ. of New York at Stony Brook, Stony Brook, NY (US)); Harrison, L.H.; McCullough, D.L. (Wake Forest Univ. Medical Center, Winston-Salem, NC (US))

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL.

  19. State of the art extracorporeal shock wave lithotripsy

    International Nuclear Information System (INIS)

    Kandel, L.B.; Harrison, L.H.; McCullough, D.L.

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL

  20. Standing shocks in adiabatic black hole accretion of rotating matter

    International Nuclear Information System (INIS)

    Abramowicz, M.A.; Chakrabarti, S.K.

    1988-08-01

    We present all the solutions for stationary, axially symmetric, transonic, adiabatic flows with polytropic, rotating fluid configurations of small transverse thickness, in an arbitrarily chosen potential. Special attention is paid to the formation of the standing shocks in the case of black hole accretion and winds. We point out the possibility of three types of shocks depending upon three extreme physical conditions at the shocks. These are: Rankine-Hugoniot shocks, isentropic compression waves, and isothermal shocks. We write down the shock conditions for these three cases and discuss briefly the physical situations under which these shocks may form. A complete discussion on the properties of these shocks will be presented elsewhere. (author). 21 refs, 4 figs

  1. The theory of ionizing shock waves in a magnetic field

    International Nuclear Information System (INIS)

    Liberman, M.A.; Velikovich, A.L.

    1981-01-01

    The general theory of ionizing shock waves in a magnetic field is constructed. The theory takes into account precursor ionization of a neutral gas ahead of the shock wave front, caused by photo-ionization, as well as by the impact ionization with electrons accelerated by a transverse electric field induced by the shock front in the incident flow of a neutral gas. The concept of shock wave ionization stability, being basic in the theory of ionizing shock waves in a magnetic field, is introduced. The ionizing shock wave structures are shown to transform from the GD regime at a low shock velocity to the MHD regime at an enhanced intensity of the shock wave. The abruptness of such a transition is determined by precursor photo-ionization. (author)

  2. Biological biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Jorge-Herrero, E. [Servicio de Cirugia Experimental. Clinica Puerta de Hierro, Madrid (Spain)

    1997-05-01

    There are a number of situations in which substances of biological origin are employed as biomaterials. Most of them are macromolecules derived from isolated connective tissue or the connective tissue itself in membrane form, in both cases, the tissue can be used in its natural form or be chemically treated. In other cases, certain blood vessels can be chemically pretreated and used as vascular prostheses. Proteins such as albumin, collagen and fibrinogen are employed to coat vascular prostheses. Certain polysaccharides have also been tested for use in controlled drug release systems. Likewise, a number of tissues, such as dura mater, bovine pericardium, procine valves and human valves, are used in the preparation of cardiac prostheses. We also use veins from animals or humans in arterial replacement. In none of these cases are the tissues employed dissimilar to the native tissues as they have been chemically modified, becoming a new bio material with different physical and biochemical properties. In short, we find that natural products are being utilized as biomaterials and must be considered as such; thus, it is necessary to study both their chemicobiological and physicomechanical properties. In the present report, we review the current applications, problems and future prospects of some of these biological biomaterials. (Author) 84 refs.

  3. Acceleration mechanisms flares, magnetic reconnection and shock waves

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1979-01-01

    Several mechanisms are briefly discussed for the acceleration of particles in the astrophysical environment. Included are hydrodynamic acceleration, spherically convergent shocks, shock and a density gradient, coherent electromagnetic acceleration, the flux tube origin, symmetries and instabilities, reconnection, galactic flares, intergalactic acceleration, stochastic acceleration, and astrophysical shocks. It is noted that the supernova shock wave models still depend critically on the presupernova star structure and the assumption of highly compact presupernova models for type I supernovae. 37 references

  4. Multi-layer protective armour for underwater shock wave mitigation

    OpenAIRE

    Ahmed Hawass; Hosam Mostafa; Ahmed Elbeih

    2015-01-01

    The effect of underwater shock wave on different target plates has been studied. An underwater shock wave generator (shock tube) was used to study the interactions between water and different constructed targets which act as shock wave mitigation. Target plates, composed of sandwich of two aluminum sheets with rubber and foam in between, were prepared and studied. For comparison, the target plates composed of triple aluminum sheets were tested. The study includes the testing of the selected p...

  5. Dynamic testing of airplane shock-absorbing struts

    Science.gov (United States)

    Langer, P; Thome, W

    1932-01-01

    Measurement of perpendicular impacts of a landing gear with different shock-absorbing struts against the drum testing stand. Tests were made with pneumatic shock absorbers having various degrees of damping, liquid shock absorbers, steel-spring shock absorbers and rigid struts. Falling tests and rolling tests. Maximum impact and gradual reduction of the impacts in number and time in the falling tests. Maximum impact and number of weaker impacts in rolling tests.

  6. GEOMETRICAL OPTIMIZATION OF VEHICLE SHOCK ABSORBERS WITH MR FLUID

    OpenAIRE

    ENGIN, Tahsin; PARLAK, Zekeriya; ŞAHIN, Ismail; ÇALLI, Ismail

    2016-01-01

    Magnetorheological (MR) shock absorber have received remarkable attention in the last decade due to being a potential technology to conduct semi-active control in structures and mechanical systems in order to effectively suppress vibration. To develop performance of MR shock absorbers, optimal design of the dampers should be considered. The present study deals with optimal geometrical modeling of a MR shock absorber. Optimal design of the present shock absorber was carried out by using Taguch...

  7. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 µm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of ...

  8. Shock and vibration technology with applications to electrical systems

    Science.gov (United States)

    Eshleman, R. L.

    1972-01-01

    A survey is presented of shock and vibration technology for electrical systems developed by the aerospace programs. The shock environment is surveyed along with new techniques for modeling, computer simulation, damping, and response analysis. Design techniques based on the use of analog computers, shock spectra, optimization, and nonlinear isolation are discussed. Shock mounting of rotors for performance and survival, and vibration isolation techniques are reviewed.

  9. Investment shocks and the relative price of investment

    OpenAIRE

    Justiniano, Alejandro; Primiceri, Giorgio E.; Tambalotti, Andrea

    2009-01-01

    We estimate a New-Neoclassical Synthesis model of the business cycle with two investment shocks. The first, an investment-specific technology shock, affects the transformation of consumption into investment goods and is identified with the relative price of investment. The second shock affects the production of installed capital from investment goods or, more broadly, the transformation of savings into future capital input. We find that this shock is the most important driver of U.S. business...

  10. On cylindrically converging shock waves shaped by obstacles

    Energy Technology Data Exchange (ETDEWEB)

    Eliasson, V; Henshaw, W D; Appelo, D

    2007-07-16

    Motivated by recent experiments, numerical simulations were performed of cylindrically converging shock waves. The converging shocks impinged upon a set of zero to sixteen regularly space obstacles. For more than two obstacles the resulting diffracted shock fronts formed polygonal shaped patterns near the point of focus. The maximum pressure and temperature as a function of number of obstacles were studied. The self-similar behavior of cylindrical, triangular and square-shaped shocks were also investigated.

  11. Chemical kinetics studies at high temperatures using shock tubes

    OpenAIRE

    Rajakumar, B; Anandraj, D; Reddy, KPJ; Arunan, E

    2002-01-01

    Shock tube is an unique facility to create temperature gradients exceeding million degrees Kelvin per second. We have established two shock tubes for measuring the kinetic reaction rates at high temperatures with two different but complementary detection techniques. The first one is a single pulse shock tube, in which the reflected shock is used to heat the molecules. The equilibrated products are analyzed by gas chromatograph and infrared spectrometer. The second one uses laser-schlieren sys...

  12. Remarks on stability of magneto-elastic shocks

    Directory of Open Access Journals (Sweden)

    Włodzimierz Domański

    2015-12-01

    Full Text Available The problem of stability of plane shock waves for a model of perfect magnetoelasticityis investigated. Important mathematical properties, like loss of strict hyperbolicityand loss of genuine nonlinearity, and their consequences for the stability ofmagneto-elastic shocks are discussed. It is shown that some of these shocks do not satisfyclassical Lax stability conditions. Both compressible and incompressible models ofmagneto-elasticity are discussed.[b]Keywords[/b]: perfect magneto-elasticity, shock waves, stability conditions

  13. The Transmission of Liquidity Shocks to the Real Economy

    DEFF Research Database (Denmark)

    Dursun-de Neef, Özlem

    2012-01-01

    This paper uses the 2007-2009 financial crisis as a negative liquidity shock on banks to analyze their lending behavior and study the differences between US and euro-area banks. When faced with a negative liquidity shock, US banks transmitted liquidity shocks to the real economy by reducing...... of the Federal Reserve in the US and the ECB in the euro area has led to differences in the transmission of liquidity shocks to the real economy....

  14. Line emission processes in atomic and molecular shocks

    International Nuclear Information System (INIS)

    Shull, J.M.

    1988-01-01

    The review discusses the observations and theoretical models of interstellar shock waves in diffuse and molecular clouds. After summarizing the relevant gas dynamics, atomic, molecular and grain processes, and physics of radiative and magnetic precursors, the author describes observational diagnostics of shocks. This paper concludes with a discussion of two topics: unstable or non-steady shocks and thermal conduction in metal-rich shocks

  15. Severe sepsis and septic shock [author's reply

    NARCIS (Netherlands)

    Angus, Derek C.; van der Poll, Tom

    2013-01-01

    To the Editor: We would like to address two potentially confusing issues concerning venous oxygen saturation (Svo(2)) as presented in Table 1 of the review by Angus and van der Poll (Aug. 29 issue).(1) First, Table 1 suggests that Svo(2) is raised in sepsis, severe sepsis, and septic shock.

  16. Shock wave fabricated ceramic-metal nozzles

    NARCIS (Netherlands)

    Carton, E.P.; Stuivinga, M.E.C.; Keizers, H.L.J.; Verbeek, H.J.; Put, P.J. van der

    1999-01-01

    Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti

  17. Molecular Diagnostics of Supernova Remnant Shocks

    Science.gov (United States)

    Lazendic, J. S.; Wardle, M.; Green, A. J.; Whiteoak, J. B.; Burton, M. G.

    We have undertaken a study of radio and infrared molecular-line emission towards several SNRs in order to investigate molecular signatures of SNR shocks, and to test models for OH maser production in SNRs. Here we present results on G349.7+0.2.

  18. Theory and Experiment on Radiative Shocks

    Science.gov (United States)

    Drake, R. Paul

    2005-07-01

    The current generation of high-energy-density research facilities has enabled the beginnings of experimental studies of radiation hydrodynamic systems, common in astrophysics but difficult to produce in the laboratory. Radiative shock experiments specifically have been a topic of increasing effort in recent years. Our group and collaborators [1] have emphasized the radiographic observation of structure in radiative shocks. These shocks have been produced on the Omega laser by driving a Be piston through Xenon at velocities above 100 km/s. The talk will summarize these experiments and their results. Interpreting these and other experiments is hampered by the limited range of assumptions used in published theories, and by the limitations in readily available simulation tools. This has motivated an examination of radiative shock theory [2]. The talk will summarize the key issues and present results for specific cases. [ 1 ] Gail Glendinning, Ted Perry, Bruce Remington, Jim Knauer, Tom Boehly, and other members of the NLUF Experimental Astrophysics Team. Publications: Reighard et al., Phys. Rev. Lett. submitted; Leibrandt, et al., Ap J., in press, Reighard et al., IFSA 03 Proceedings, Amer. Nucl. Soc. (2004). [2] Useful discussions with Dmitri Ryutov and Serge Bouquet. Supported by the NNSA programs via DOE Grants DE-FG52-03NA00064 and DE FG53 2005 NA26014

  19. Physics of intermediate shocks: A review

    Science.gov (United States)

    Karimabadi, H.

    1995-01-01

    Intermediate shocks (ISs) lead to a transition from super-Alfvenic to sub-Alfvenic flow and are different from slow and fast shocks in that an IS rotates the component of the magnetic field tangent to the shock plane by 180 deg. Another peculiarity of ISs is that for the same upstream conditions an IS can have two different downstream states. There also exist a second class of ISs which rotate the magnetic field by an angle other than 180 deg. Due to their noncoplanar nature they cannot be time-stationary and are referred to as time-dependent intermediate shocks (TDIS). The existence of ISs has been the subject of much controversy over the years. Early studies questioned the physical reality of ISs. However, the studies of ISs found a new impetus when C.C. Wu showed that ISs do exist and are stable within the resistive MHD framework. In this paper, after a brief historical overview of the subject, we will review the latest developments in the study of ISs. In particular, we will address the questions of stability and structure of ISs and the relationship between ISs and other discontinuities. One of the recent developments has been the finding that ISs can be unsteady, reforming in time. Details of this process will be discussed. Finally, we examine the effect of anisotropy on the resolutions and discuss the relevance of ISs to the observed field rotations at the Earth's magnetopause.

  20. Flow control for oblique shock wave reflections

    NARCIS (Netherlands)

    Giepman, R.H.M.

    2016-01-01

    Shock wave-boundary layer interactions are prevalent in many aerospace applications that involve transonic or supersonic flows. Such interactions may lead to boundary layer separation, flow unsteadiness and substantial losses in the total pressure. Flow control techniques can help to mitigate these

  1. 33 CFR 183.584 - Shock test.

    Science.gov (United States)

    2010-07-01

    ... SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.584 Shock test. A fuel tank is tested by... the boat, apply 1000 cycles of 25g vertical accelerations at a rate of 80 cycles or less per minute... manufactured for installation with its center of gravity aft of the half length of the boat, apply 1000 cycles...

  2. Shock absorbing structure for nuclear fuel assemblies

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1981-01-01

    A hydraulic apparatus is described that absorbs shocks that may be applied to fuel assemblies. Spring pads mounted on the upper end fittings of the fuel assemblies have plungers that move within hollow guide posts attached to the upper grids of the fuel assemblies. (L.L.)

  3. Macroeconomic shocks and firms' labor adjustment

    DEFF Research Database (Denmark)

    Eriksson, Tor

    2013-01-01

    This article discusses some recent research which aims at producing evidence on how firms adjust their employment in response to output shocks using micro-level data and with a particular focus on the relationship between worker and job flows. The evidence presented is mainly based on Danish data...

  4. Income Shocks and Adolescent Mental Health

    Science.gov (United States)

    Baird, Sarah; de Hoop, Jacobus; Ozler, Berk

    2013-01-01

    We investigate the effects of a positive income shock on mental health among adolescent girls using evidence from a cash transfer experiment in Malawi. Offers of cash transfers strongly reduced psychological distress among baseline schoolgirls. However, these large beneficial effects declined with increases in the transfer amount offered to the…

  5. Strong imploding shock, the representative curve

    International Nuclear Information System (INIS)

    Mishkin, E.A.; Alejaldre, C.

    1981-01-01

    The representative curve of the ideal gas behind the front of a spherically, or cylindrically, symmetric strong imploding shock is shown to pass through the point where the reduced pressure is maximum, P(xisub(m)) = Psub(m)sub(a)sub(x). (orig.)

  6. Shock compression and quasielastic release in tantalum

    International Nuclear Information System (INIS)

    Johnson, J.N.; Hixson, R.S.; Tonks, D.L.; Gray, G.T. III

    1994-01-01

    Previous studies of quasielastic release in shock-loaded FCC metals have shown a strong influence of the defect state on the leading edge, or first observable arrival, of the release wave. This is due to the large density of pinned dislocation segments behind the shock front, their relatively large pinning separation, and a very short response time as determined by the drag coefficient in the shock-compressed state. This effect is entirely equivalent to problems associated with elastic moduli determination using ultrasonic methods. This is particularly true for FCC metals, which have an especially low Peierls stress, or inherent lattice resistance, that has little influence in pinning dislocation segments and inhibiting anelastic deformation. BCC metals, on the other hand, have a large Peierls stress that essentially holds dislocation segments in place at low net applied shear stresses and thus allows fully elastic deformation to occur in the complete absence of anelastic behavior. Shock-compression and release experiments have been performed on tantalum (BCC), with the observation that the leading release disturbance is indeed elastic. This conclusion is established by examination of experimental VISAR records taken at the tantalum/sapphire (window) interface in a symmetric-impact experiment which subjects the sample to a peak longitudinal stress of approximately 7.3 GPa, in comparison with characteristic code calculations. copyright 1994 American Institute of Physics

  7. Radiating shocks and condensations in flares

    International Nuclear Information System (INIS)

    Fisher, G.H.

    1985-01-01

    Rapid energy release (by either ''thick target'' (beam) or ''thermal'' models of heating) in solar flare loop models usually leads to ''chromospheric evaporation,'' the process of heating cool chromospheric material to coronal temperatures, and the resulting increase in hot soft x-ray emitting plasma. The evaporated plasma flows up into the coronal portion of the loop because of the increased pressure in the evaporated region. However, the pressure increase also leads to a number of interesting phenomena in the flare chromosphere, which will be the subject of this paper. The sudden pressure increase in the evaporated plasma initiates a downward moving ''chromospheric condensation,'' an overdense region which gradually decelerates as it accretes material and propagates into the gravitationally stratified chromosphere. Solutions to an equation of motion for this condensation shows that its motion decays after about one minute of propagation into the chromosphere. When the front of this downflowing region is supersonic relative to the atmosphere ahead of it, a radiating shock will form. If the downflow is rapid enough, the shock strength should be sufficient to excite uv radiation normally associated with the transition region, and furthermore, the radiating shock will be brighter than the transition region. These results lead to a number of observationally testable relationships between the optical and ultraviolet spectra from the condensation and radiating shock

  8. Geodesics analysis of colliding gravitational shock waves

    International Nuclear Information System (INIS)

    Pozdeeva, E.

    2011-01-01

    Full text: (author)We consider collision of charged gravitational shock waves with infinite transverse extension (charged gravitational walls). We study the influence of the charges on the trapped surface formation in the charged walls collision. This consideration has applications in the in heavy ion collisions using a holographic approach in which the charge plays the role of the chemical potential

  9. A nova outburst powered by shocks

    Science.gov (United States)

    Li, Kwan-Lok; Metzger, Brian D.; Chomiuk, Laura; Vurm, Indrek; Strader, Jay; Finzell, Thomas; Beloborodov, Andrei M.; Nelson, Thomas; Shappee, Benjamin J.; Kochanek, Christopher S.; Prieto, José L.; Kafka, Stella; Holoien, Thomas W.-S.; Thompson, Todd A.; Luckas, Paul J.; Itoh, Hiroshi

    2017-10-01

    Classical novae are runaway thermonuclear burning events on the surfaces of accreting white dwarfs in close binary star systems, sometimes appearing as new naked-eye sources in the night sky1. The standard model of novae predicts that their optical luminosity derives from energy released near the hot white dwarf, which is reprocessed through the ejected material2-5. Recent studies using the Fermi Large Area Telescope have shown that many classical novae are accompanied by gigaelectronvolt γ-ray emission6,7. This emission likely originates from strong shocks, providing new insights into the properties of nova outflows and allowing them to be used as laboratories for the study of the unknown efficiency of particle acceleration in shocks. Here, we report γ-ray and optical observations of the Milky Way nova ASASSN-16ma, which is among the brightest novae ever detected in γ-rays. The γ-ray and optical light curves show a remarkable correlation, implying that the majority of the optical light comes from reprocessed emission from shocks rather than the white dwarf8. The ratio of γ-ray to optical flux in ASASSN-16ma directly constrains the acceleration efficiency of non-thermal particles to be around 0.005, favouring hadronic models for the γ-ray emission9. The need to accelerate particles up to energies exceeding 100 gigaelectronvolts provides compelling evidence for magnetic field amplification in the shocks.

  10. Pyrotechnic Shock Analysis Using Statistical Energy Analysis

    Science.gov (United States)

    2015-10-23

    SEA subsystems. A couple of validation examples are provided to demonstrate the new approach. KEY WORDS : Peak Ratio, phase perturbation...Ballistic Shock Prediction Models and Techniques for Use in the Crusader Combat Vehicle Program,” 11th Annual US Army Ground Vehicle Survivability

  11. True versus apparent shapes of bow shocks

    Science.gov (United States)

    Tarango-Yong, Jorge A.; Henney, William J.

    2018-06-01

    Astrophysical bow shocks are a common result of the interaction between two supersonic plasma flows, such as winds or jets from stars or active galaxies, or streams due to the relative motion between a star and the interstellar medium. For cylindrically symmetric bow shocks, we develop a general theory for the effects of inclination angle on the apparent shape. We propose a new two-dimensional classification scheme for bow shapes, which is based on dimensionless geometric ratios that can be estimated from observational images. The two ratios are related to the flatness of the bow's apex, which we term planitude, and the openness of its wings, which we term alatude. We calculate the expected distribution in the planitude-alatude plane for a variety of simple geometrical and physical models: quadrics of revolution, wilkinoids, cantoids, and ancantoids. We further test our methods against numerical magnetohydrodynamical simulations of stellar bow shocks and find that the apparent planitude and alatude measured from infrared dust continuum maps serve as accurate diagnostics of the shape of the contact discontinuity, which can be used to discriminate between different physical models. We present an algorithm that can determine the planitude and alatude from observed bow shock emission maps with a precision of 10 to 20 per cent.

  12. Success of electromagnetic shock wave lithotripter asmonotherapy ...

    African Journals Online (AJOL)

    Objectives: To evaluate the success of shock wave lithotripsy (SWL) as monotherapy for solitary renalstones larger than 2 cm without ureteral stenting. Hence, if our study result demonstrates acceptable successand safety, we can recommend ESWL as a treatment option for patients with large renal calculi. Subjects and ...

  13. Shock formation in mixtures of fluids

    International Nuclear Information System (INIS)

    Virgopia, N.; Ferraioli, F.

    1987-01-01

    The problem of weak-discontinuity propagation in mixtures of two ideal fluids is examined. The presence of exchenge of momentum reduces or enhances the time for shock formation depending on the machanism with whom the exchange of momentum takes place. Numerical evaluation are also presented for mixtures of nitrogen and oxygen simulating dry-air models

  14. Shock buffer for nuclear control assembly

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1977-01-01

    A shock buffer is provided for the gradual deceleration of a rapidly descending control element assembly in a nuclear reactor. The interactive buffer components are associated respectively with the movable control element assembly and part of the upper guide structure independent of and spaced from the fuel assemblies of the reactor

  15. Calculating Shocks In Flows At Chemical Equilibrium

    Science.gov (United States)

    Eberhardt, Scott; Palmer, Grant

    1988-01-01

    Boundary conditions prove critical. Conference paper describes algorithm for calculation of shocks in hypersonic flows of gases at chemical equilibrium. Although algorithm represents intermediate stage in development of reliable, accurate computer code for two-dimensional flow, research leading up to it contributes to understanding of what is needed to complete task.

  16. Shocked plate metal atom oxidation laser

    International Nuclear Information System (INIS)

    De Koker, J.G.; Rice, W.W. Jr.; Jensen, R.J.

    1975-01-01

    A method and apparatus for producing metal atom oxidation lasing wherein an explosively shocked grooved metal plate produces metal vapor jets directed through an appropriate gaseous oxidizer are described. Reaction of the metal vapor with the oxidizer produces molecular species having a population inversion therein. (U.S.)

  17. Inferring Pre-shock Acoustic Field From Post-shock Pitot Pressure Measurement

    Science.gov (United States)

    Wang, Jian-Xun; Zhang, Chao; Duan, Lian; Xiao, Heng; Virginia Tech Team; Missouri Univ of Sci; Tech Team

    2017-11-01

    Linear interaction analysis (LIA) and iterative ensemble Kalman method are used to convert post-shock Pitot pressure fluctuations to static pressure fluctuations in front of the shock. The LIA is used as the forward model for the transfer function associated with a homogeneous field of acoustic waves passing through a nominally normal shock wave. The iterative ensemble Kalman method is then employed to infer the spectrum of upstream acoustic waves based on the post-shock Pitot pressure measured at a single point. Several test cases with synthetic and real measurement data are used to demonstrate the merits of the proposed inference scheme. The study provides the basis for measuring tunnel freestream noise with intrusive probes in noisy supersonic wind tunnels.

  18. Physical mechanisms in shock-induced turbulent separated flow

    Science.gov (United States)

    Dolling, D. S.

    1987-12-01

    It has been demonstrated that the flow downstream of the moving shock is separated and that the foot of the shock is effectively the instantaneous separation point. The shock induced turbulent separation is an intermittant process and the separation line indicated by surface tracer methods, such as kerosene-lampblack, is a downstream boundary of a region of intermittent separation.

  19. 21 CFR 876.5990 - Extracorporeal shock wave lithotripter.

    Science.gov (United States)

    2010-04-01

    ..., control console, imaging/localization system, and patient table. Prior to treatment, the urinary stone is targeted using either an integral or stand-alone localization/imaging system. Shock waves are typically... shock wave lithotripter. (a) Identification. An extracorporeal shock wave lithotripter is a device that...

  20. School Shock: A Psychodynamic View of Learning Disability.

    Science.gov (United States)

    Zitani, E. Alfredo

    Learning disability is seen to be a dissociative disorder (school shock) similar to shell shock in wartime. The shell shock model is explained to focus diagnosis and treatment of learning disabilities around the dynamics of the predisposing unconscious conflict, the dynamics in the environment, the mechanism which allows these two conditions to…

  1. Idiosyncratic Shocks, Child Labor and School Attendance in Indonesia

    Science.gov (United States)

    Kharisma, Bayu

    2017-01-01

    This paper investigates the effect of various idiosyncratic shocks against child labor, child labor hour and school attendance. Also, the role of the assets held by households as one of the coping strategies to mitigate the effects of shocks. The results show that various idiosyncratic shocks that encourage child labor is generally caused by crop…

  2. Shock stand off Calculations for Hemisphere in Hypersonic Flows

    International Nuclear Information System (INIS)

    Hanif, M.; Ghaffar, A.; Bilal, S.; Zahir, S.; Khan, M.A.

    2004-01-01

    The shape and location of shock has been studied by solving the axi symmetric Navier Stokes Equations for a hemisphere in hypersonic flow. The effect of Mach number on shock stand-off distance has been investigated. It is found that the shock location varies with Mach number and the free stream conditions at a given nose radius. (author)

  3. Simple model for decay of laser generated shock waves

    International Nuclear Information System (INIS)

    Trainor, R.J.

    1980-01-01

    A simple model is derived to calculate the hydrodynamic decay of laser-generated shock waves. Comparison with detailed hydrocode simulations shows good agreement between calculated time evolution of shock pressure, position, and instantaneous pressure profile. Reliability of the model decreases in regions of the target where superthermal-electron preheat effects become comparable to shock effects

  4. Interaction of Accretion Shocks with Winds Kinsuk Acharya , Sandip ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Accretion shocks are known to oscillate in presence of cool- ing processes in the disk. This oscillation may also cause quasi-periodic oscillations of black holes. In the presence of strong winds, these shocks have oscillations in vertical direction as well. We show examples of shock oscillations under the influence of ...

  5. Heat shock protection against cold stress of Drosophila melanogaster

    OpenAIRE

    Burton, Vicky; Mitchell, Herschel K.; Young, Patricia; Petersen, Nancy S.

    1988-01-01

    Heat shock protein synthesis can be induced during recovery from cold treatment of Drosophila melanogaster larvae. Survival of larvae after a cold treatment is dramatically improved by a mild heat shock just before the cold shock. The conditions which induce tolerance to cold are similar to those which confer tolerance to heat.

  6. Fluid dynamics of the shock wave reactor

    Science.gov (United States)

    Masse, Robert Kenneth

    2000-10-01

    High commercial incentives have driven conventional olefin production technologies to near their material limits, leaving the possibility of further efficiency improvements only in the development of entirely new techniques. One strategy known as the Shock Wave Reactor, which employs gas dynamic processes to circumvent limitations of conventional reactors, has been demonstrated effective at the University of Washington. Preheated hydrocarbon feedstock and a high enthalpy carrier gas (steam) are supersonically mixed at a temperature below that required for thermal cracking. Temperature recovery is then effected via shock recompression to initiate pyrolysis. The evolution to proof-of-concept and analysis of experiments employing ethane and propane feedstocks are presented. The Shock Wave Reactor's high enthalpy steam and ethane flows severely limit diagnostic capability in the proof-of-concept experiment. Thus, a preliminary blow down supersonic air tunnel of similar geometry has been constructed to investigate recompression stability and (especially) rapid supersonic mixing necessary for successful operation of the Shock Wave Reactor. The mixing capabilities of blade nozzle arrays are therefore studied in the air experiment and compared with analytical models. Mixing is visualized through Schlieren imaging and direct photography of condensation in carbon dioxide injection, and interpretation of visual data is supported by pressure measurement and flow sampling. The influence of convective Mach number is addressed. Additionally, thermal behavior of a blade nozzle array is analyzed for comparison to data obtained in the course of succeeding proof-of-concept experiments. Proof-of-concept is naturally succeeded by interest in industrial adaptation of the Shock Wave Reactor, particularly with regard to issues involving the scaling and refinement of the shock recompression. Hence, an additional, variable geometry air tunnel has been constructed to study the parameter

  7. Fundamentals of Non-relativistic Collisionless Shock Physics: IV. Quasi-Parallel Supercritical Shocks

    OpenAIRE

    Treumann, R. A.; Jaroschek, C. H.

    2008-01-01

    1. Introduction, 2. The (quasi-parallel) foreshock; Ion foreshock, Ion foreshock boundary region; Diffuse ions;Low-frequency upstream waves; Ion beam waves; The expected wave modes; Observations; Diffuse ion waves; Electron foreshock; Electron beams; Langmuir waves; stability of the electron beam; Electron foreshock boundary waves; Nature of electron foreshock waves; Radiation; Observations; Interpretation; 3. Quasi-parallel shock reformation; Low-Mach number quasi-parallel shocks; Turbulent ...

  8. Cardiogenic shock. Current concepts in management.

    Science.gov (United States)

    Balakumaran, K; Hugenholtz, P G

    1986-10-01

    This article presents a categorisation of circulatory shock and discusses the causes, haemodynamics, and clinical recognition of cardiogenic shock. The first step in the management strategy in cardiogenic shock is to guide the patient from the state of shock to one of managed haemodynamic stability. The therapeutic manoeuvres of this first step constitute the management tactics, which can be grouped under 3 general headings: (a) making the most of a malfunctioning heart; (b) improving the state of the heart; and (c) reducing the demands on the heart. In order to make the most of the heart, i.e. to get the highest possible output at the lowest possible cost, clinicians need to use their judgement in stimulating an overtaxed heart on the one hand, and in manipulating the loads on it (the preload and afterload) on the other, for although these methods may be advantageous, they are not without their pitfalls. Efforts to improve the state of the heart often necessitate surgical (e.g. mitral valve replacement) or semisurgical (e.g. coronary angiography and recanalisation) techniques, although intravenous antithrombotic agents may achieve comparable results in a few cases at the bedside. Reducing the demands on the heart is an active process involving the takeover of at least a part of the work of the heart by ancillary devices such as the intra-aortic balloon pump, and of the work of breathing by intubation and artificial ventilation. The individuality of each case of cardiogenic shock emphasises the need for empirical modulation of therapy based on feedback information obtained by haemodynamic monitoring.

  9. Biological effects

    International Nuclear Information System (INIS)

    Trott, K.R.

    1973-01-01

    Following an introduction into the field of cellular radiation effect considering the most important experimental results, the biological significance of the colony formation ability is brought out. The inactivation concept of stem cells does not only prove to be good, according to the present results, in the interpretation of the pathogenesis of acute radiation effects on moult tissue, it also enables chronicle radiation injuries to be interpreted through changes in the fibrous part of the organs. Radiation therapy of tumours can also be explained to a large extent by the radiation effect on the unlimited reproductiveness of tumour cells. The more or less similar dose effect curves for healthy and tumour tissue in practice lead to intermittent irradiation. The dependence of the intermittent doses and intervals on factors such as Elkind recovery, synchronisation, redistribution, reoxygenation, repopulation and regeneration are reviewed. (ORU/LH) [de

  10. Shock dynamics of weak imploding cylindrical and spherical shock waves with non-ideal gas effects

    International Nuclear Information System (INIS)

    Anand, R K

    2013-01-01

    The author (Anand 2012 Astrophys. Space Sci. 342 377–88) recently obtained jump relations across a shock front in non-ideal gas flow taking into consideration the equation of state for a non-ideal gas as given by Landau and Lifshitz. In this paper an analytical solution for one-dimensional adiabatic flow behind weak converging shock waves propagating in a non-ideal gas is obtained by using Whitham's (1974 Linear and Nonlinear Waves (New York: Wiley)) geometrical shock dynamics approach. The effects of an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and (iii) the adiabatic index of the gas, on the shock velocity, pressure, density, particle velocity, adiabatic compressibility and the change in entropy across the shock front, are analyzed. The results provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the imploding shock front. (paper)

  11. Shock therapy: Gris Gun's shock absorber can take the punch

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2000-04-01

    A newly developed shock impedance tool that isolates downhole tools that measure the effects of well stimulation techniques from being damaged by the violent shaking caused by various well stimulation techniques which combine perforating and propellant technology in a single tool, is discussed. The shock exerted by a perforating gun can exceed 25,000 G forces within 100 to 300 milliseconds, may damage or even destroy the sensitive electronics housed in the various recorders that record data about fracture gradients, permeability and temperature. The shock absorber developed by Tesco Gris Gun and Computalog, incorporates the mechanics of a piston style shock absorber in combination with a progressive spring stack and energy-dampening silicone oil chambers. The end results is an EUE 'slim line' assembly that is adaptable between the gun perforating string and the electronic equipment. It is typically attached below, reducing the shock load by as much as 90 per cent. The shock absorber is now available commercially through Gris Gun's exclusive distributorship. An improved version, currently under development, will be used for wireline perforating and tubing-conveyed perforating applications. 2 figs.

  12. INJECTION TO RAPID DIFFUSIVE SHOCK ACCELERATION AT PERPENDICULAR SHOCKS IN PARTIALLY IONIZED PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Yutaka, E-mail: ohira@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258 (Japan)

    2016-08-10

    We present a three-dimensional hybrid simulation of a collisionless perpendicular shock in a partially ionized plasma for the first time. In this simulation, the shock velocity and upstream ionization fraction are v {sub sh} ≈ 1333 km s{sup −1} and f {sub i} ∼ 0.5, which are typical values for isolated young supernova remnants (SNRs) in the interstellar medium. We confirm previous two-dimensional simulation results showing that downstream hydrogen atoms leak into the upstream region and are accelerated by the pickup process in the upstream region, and large magnetic field fluctuations are generated both in the upstream and downstream regions. In addition, we find that the magnetic field fluctuations have three-dimensional structures and the leaking hydrogen atoms are injected into the diffusive shock acceleration (DSA) at the perpendicular shock after the pickup process. The observed DSA can be interpreted as shock drift acceleration with scattering. In this simulation, particles are accelerated to v ∼ 100 v {sub sh} ∼ 0.3 c within ∼100 gyroperiods. The acceleration timescale is faster than that of DSA in parallel shocks. Our simulation results suggest that SNRs can accelerate cosmic rays to 10{sup 15.5} eV (the knee) during the Sedov phase.

  13. Impact of Shock Front Rippling and Self-reformation on the Electron Dynamics at Low-Mach-number Shocks

    Science.gov (United States)

    Yang, Zhongwei; Lu, Quanming; Liu, Ying D.; Wang, Rui

    2018-04-01

    Electron dynamics at low-Mach-number collisionless shocks are investigated by using two-dimensional electromagnetic particle-in-cell simulations with various shock normal angles. We found: (1) The reflected ions and incident electrons at the shock front provide an effective mechanism for the quasi-electrostatic wave generation due to the charge-separation. A fraction of incident electrons can be effectively trapped and accelerated at the leading edge of the shock foot. (2) At quasi-perpendicular shocks, the electron trapping and reflection is nonuniform due to the shock rippling along the shock surface and is more likely to take place at some locations accompanied by intense reflected ion-beams. The electron trapping process has a periodical evolution over time due to the shock front self-reformation, which is controlled by ion dynamics. Thus, this is a cross-scale coupling phenomenon. (3) At quasi-parallel shocks, reflected ions can travel far back upstream. Consequently, quasi-electrostatic waves can be excited in the shock transition and the foreshock region. The electron trajectory analysis shows these waves can trap electrons at the foot region and reflect a fraction of them far back upstream. Simulation runs in this paper indicate that the micro-turbulence at the shock foot can provide a possible scenario for producing the reflected electron beam, which is a basic condition for the type II radio burst emission at low-Mach-number interplanetary shocks driven by Coronal Mass Ejections (CMEs).

  14. On the interplay between cosmological shock waves and their environment

    Science.gov (United States)

    Martin-Alvarez, Sergio; Planelles, Susana; Quilis, Vicent

    2017-05-01

    Cosmological shock waves are tracers of the thermal history of the structures in the Universe. They play a crucial role in redistributing the energy within the cosmic structures and are also amongst the main ingredients of galaxy and galaxy cluster formation. Understanding this important function requires a proper description of the interplay between shocks and the different environments where they can be found. In this paper, an Adaptive Mesh Refinement (AMR) Eulerian cosmological simulation is analysed by means of a shock-finding algorithm that allows to generate shock wave maps. Based on the population of dark matter halos and on the distribution of density contrast in the simulation, we classify the shocks in five different environments. These range from galaxy clusters to voids. The shock distribution function and the shocks power spectrum are studied for these environments dynamics. We find that shock waves on different environments undergo different formation and evolution processes, showing as well different characteristics. We identify three different phases of formation, evolution and dissipation of these shock waves, and an intricate migration between distinct environments and scales. Shock waves initially form at external, low density regions and are merged and amplified through the collapse of structures. Shock waves and cosmic structures follow a parallel evolution. Later on, shocks start to detach from them and dissipate. We also find that most of the power that shock waves dissipate is found at scales of k ˜0.5 Mpc^{-1}, with a secondary peak at k ˜8 Mpc^{-1}. The evolution of the shocks power spectrum confirms that shock waves evolution is coupled and conditioned by their environment.

  15. Effects of Shock and Turbulence Properties on Electron Acceleration

    Science.gov (United States)

    Qin, G.; Kong, F.-J.; Zhang, L.-H.

    2018-06-01

    Using test particle simulations, we study electron acceleration at collisionless shocks with a two-component model turbulent magnetic field with slab component including dissipation range. We investigate the importance of the shock-normal angle θ Bn, magnetic turbulence level {(b/{B}0)}2, and shock thickness on the acceleration efficiency of electrons. It is shown that at perpendicular shocks the electron acceleration efficiency is enhanced with the decrease of {(b/{B}0)}2, and at {(b/{B}0)}2=0.01 the acceleration becomes significant due to a strong drift electric field with long time particles staying near the shock front for shock drift acceleration (SDA). In addition, at parallel shocks the electron acceleration efficiency is increasing with the increase of {(b/{B}0)}2, and at {(b/{B}0)}2=10.0 the acceleration is very strong due to sufficient pitch-angle scattering for first-order Fermi acceleration, as well as due to the large local component of the magnetic field perpendicular to the shock-normal angle for SDA. On the other hand, the high perpendicular shock acceleration with {(b/{B}0)}2=0.01 is stronger than the high parallel shock acceleration with {(b/{B}0)}2=10.0, the reason might be the assumption that SDA is more efficient than first-order Fermi acceleration. Furthermore, for oblique shocks, the acceleration efficiency is small no matter whether the turbulence level is low or high. Moreover, for the effect of shock thickness on electron acceleration at perpendicular shocks, we show that there exists the bendover thickness, L diff,b. The acceleration efficiency does not noticeably change if the shock thickness is much smaller than L diff,b. However, if the shock thickness is much larger than L diff,b, the acceleration efficiency starts to drop abruptly.

  16. Creating biological nanomaterials using synthetic biology

    International Nuclear Information System (INIS)

    Rice, MaryJoe K; Ruder, Warren C

    2014-01-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems. (review)

  17. Creating biological nanomaterials using synthetic biology.

    Science.gov (United States)

    Rice, MaryJoe K; Ruder, Warren C

    2014-02-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  18. Two dimensional hybrid simulation of a curved bow shock

    International Nuclear Information System (INIS)

    Thomas, V.A.; Winske, D.

    1990-01-01

    Results are presented from two dimensional hybrid simulations of curved collisionless supercritical shocks, retaining both quasi-perpendicular and quasi-parallel sections of the shock in order to study the character and origin of the foreshock ion population. The simulations demonstrate that the foreshock ion population is dominated by ions impinging upon the quasi-parallel side of the shock, while nonlocal transport from the quasi-perpendicular side of the shock into the foreshock region is minimal. Further, it is shown that the ions gain energy by drifting significantly in the direction of the convection electric field through multiple shock encounters

  19. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J.P. (GRECO ILM, Laboratoire d' Energetique et Detonique, E.N.S.M.A., 86 - Poitiers (France))

    1984-11-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 ..mu..m wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined.

  20. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 μm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined

  1. Radiography for a Shock-accelerated Liquid Layer

    International Nuclear Information System (INIS)

    P. Meekunnasombat J.G. Oakley/inst M.H. Anderson R. Bonazza

    2005-01-01

    This program supported the experimental study of the interaction of planar shock waves with both solid structures (a single cylinder or a bank of cylinders) and single and multiple liquid layers. Objectives of the study included: characterization of the shock refraction patterns; measurements of the impulsive loading of the solid structures; observation of the response of the liquid layers to shock acceleration; assessment of the shock-mitigation effects of single and multiple liquid layers. The uploaded paper is intended as a final report for the entire funding period. The poster described in the paper won the Best Poster Award at the 25 International Symposium on Shock Waves

  2. Effects of shock waves on Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Zhang Yongtao; Shu Chiwang; Zhou Ye

    2006-01-01

    A numerical simulation of two-dimensional compressible Navier-Stokes equations using a high-order weighted essentially nonoscillatory finite difference shock capturing scheme is carried out in this paper, to study the effect of shock waves on the development of Rayleigh-Taylor instability. Shocks with different Mach numbers are introduced ahead or behind the Rayleigh-Taylor interface, and their effect on the transition to instability is demonstrated and compared. It is observed that shock waves can speed up the transition to instability for the Rayleigh-Taylor interface significantly. Stronger shocks are more effective in this speed-up process

  3. SHADES, FOLDS AND INCITEMENTS BETWEEN BIOLOGY AND PEDAGOGY THE DEGREE IN BIOLOGY FROM THE NATIONAL PEDAGOGICAL UNIVERSITY

    Directory of Open Access Journals (Sweden)

    Sandra Liliana Cano Aparicio

    2016-09-01

    Full Text Available This document reflects an investigative exercise developed from elements of the toolbox of the History Group of the Pedagogical Practice and Foucauldian perspective, in this case from a source tracking and records the relationship between biology and pedagogy problematized Degree in biology from the National Pedagogical University. This relationship emerged with force, shock, nuances, resistors which gave some insight trifold and different times. Also, this paper problematizes from a Bachelor tensions, folds, demonstrations and struggles that occur when entering or science disciplines in connection with pedagogy. Furthermore, some singular relations practices of knowledge, power, subjectivity different denoting a creative practice, politics and aesthetics of Bachelor’s degree in biology.

  4. EXPERIMENTAL STUDY OF SHOCK WAVE DYNAMICS IN MAGNETIZED PLASMAS

    International Nuclear Information System (INIS)

    Podder, Nirmol K.

    2009-01-01

    In this four-year project (including one-year extension), the project director and his research team built a shock-wave-plasma apparatus to study shock wave dynamics in glow discharge plasmas in nitrogen and argon at medium pressure (1-20 Torr), carried out various plasma and shock diagnostics and measurements that lead to increased understanding of the shock wave acceleration phenomena in plasmas. The measurements clearly show that in the steady-state dc glow discharge plasma, at fixed gas pressure the shock wave velocity increases, its amplitude decreases, and the shock wave disperses non-linearly as a function of the plasma current. In the pulsed discharge plasma, at fixed gas pressure the shock wave dispersion width and velocity increase as a function of the delay between the switch-on of the plasma and shock-launch. In the afterglow plasma, at fixed gas pressure the shock wave dispersion width and velocity decrease as a function of the delay between the plasma switch-off and shock-launch. These changes are found to be opposite and reversing towards the room temperature value which is the initial condition for plasma ignition case. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  5. Do structural oil-market shocks affect stock prices?

    International Nuclear Information System (INIS)

    Apergis, Nicholas; Miller, Stephen M.

    2009-01-01

    This paper investigates how explicit structural shocks that characterize the endogenous character of oil price changes affect stock-market returns in a sample of eight countries - Australia, Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States. For each country, the analysis proceeds in two steps. First, modifying the procedure of Kilian [Not All Oil Price Shocks are Alike: Disentangling Demand and Supply Shocks in the Crude Oil Market. American Economic Review.], we employ a vector error-correction or vector autoregressive model to decompose oil-price changes into three components: oil-supply shocks, global aggregate-demand shocks, and global oil-demand shocks. The last component relates to specific idiosyncratic features of the oil market, such as changes in the precautionary demand concerning the uncertainty about the availability of future oil supplies. Second, recovering the oil-supply shocks, global aggregate-demand shocks, and global oil-demand shocks from the first analysis, we then employ a vector autoregressive model to determine the effects of these structural shocks on the stock market returns in our sample of eight countries. We find that international stock market returns do not respond in a large way to oil market shocks. That is, the significant effects that exist prove small in magnitude. (author)

  6. The Shock and Vibration Bulletin. Part 1. Opening Session, Panel Session, Shock Analysis Shock Testing, Isolation and Damping.

    Science.gov (United States)

    1977-09-01

    ORTHOTROPIC PLATES WITH VARIOUS ,I PLANFORMS AND EDGE CONDITIONS C.W. Bert, The University of Oklahoma, Norman , OK - -’ DYNAMIC RESPONSE OF LAMINATED...EVALUATION OF AN ADAPTIVE FILTER AS A DIGITAL TRACKING FILTER D.O. Smallwood and D.L. Gregory, Sandia Laboratories, Albuquerque, NM TOTAL MISSION ENVIRONMENTAL...June 1967. ration Bulletin No. 40, Part 2, 1969. 6. J. P. Barthmaier, "Shock Testing Under 2. D. 0. Smallwood , "Time History Synthesis Minicomputer

  7. Dust acoustic shock wave at high dust density

    International Nuclear Information System (INIS)

    Ghosh, Samiran; Sarkar, Susmita; Khan, Manoranjan; Avinash, K.; Gupta, M. R.

    2003-01-01

    Dust acoustic (DA) shock wave at high dust density, i.e., the dust electroacoustic (DEA) or dust Coulomb (DC) shock wave has been investigated incorporating the nonadiabatic dust charge variation. The nonlinear DEA (DC) shock wave is seen to be governed by the Korteweg-de Vries Burger equation, in which the Burger term is proportional to the nonadiabaticity generated dissipation. It is seen that the shock strength decreases but after reaching minimum, it increases as the dust space charge density |q d n d | increases and the shock strength of DA wave is greater than that of DEA (DC) wave. Moreover the DEA (DC) shock width increases appreciably with increase mass m i of the ion component of the dusty plasma but for DA shock wave the effect is weak

  8. The impact of energy price shocks on the UK economy

    International Nuclear Information System (INIS)

    2007-01-01

    This report describes the results of six scenarios considering the impact of energy price shocks on the UK economy. The six scenarios considered are: UK aggregate energy price scenario; pan-Europe aggregate energy price; global aggregate energy price; UK temporary gas price; UK permanent gas price; crude (Brent) oil price. As expected, shocks to aggregate energy prices cause the largest macroeconomic and energy demand effects (in terms of growth rate volatility). Shocks to gas prices produce a greater growth volatility for macroeconomic and energy demand than shocks to oil prices. In general terms, shocks specific to the UK market tend to produce more growth rate volatility than wider ranging price shocks (global or pan-European). All of the price shocks considered have a recursive effect on the main indicators, which tend to stabilise around the baseline level in the long run. The report summarises the results obtained in the different scenarios

  9. A shock absorber model for structure-borne noise analyses

    Science.gov (United States)

    Benaziz, Marouane; Nacivet, Samuel; Thouverez, Fabrice

    2015-08-01

    Shock absorbers are often responsible for undesirable structure-borne noise in cars. The early numerical prediction of this noise in the automobile development process can save time and money and yet remains a challenge for industry. In this paper, a new approach to predicting shock absorber structure-borne noise is proposed; it consists in modelling the shock absorber and including the main nonlinear phenomena responsible for discontinuities in the response. The model set forth herein features: compressible fluid behaviour, nonlinear flow rate-pressure relations, valve mechanical equations and rubber mounts. The piston, base valve and complete shock absorber model are compared with experimental results. Sensitivity of the shock absorber response is evaluated and the most important parameters are classified. The response envelope is also computed. This shock absorber model is able to accurately reproduce local nonlinear phenomena and improves our state of knowledge on potential noise sources within the shock absorber.

  10. Grain Destruction in a Supernova Remnant Shock Wave

    Science.gov (United States)

    Raymond, John C.; Ghavamian, Parviz; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Gaetz, Terrance J.; Sankrit, Ravi

    2014-01-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV (lambda)1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10'' behind the shock is too high compared to the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre- shock medium limit our ability to test dust destruction models in detail.

  11. Particle acceleration at shocks in the inner heliosphere

    Science.gov (United States)

    Parker, Linda Neergaard

    This dissertation describes a study of particle acceleration at shocks via the diffusive shock acceleration mechanism. Results for particle acceleration at both quasi-parallel and quasi-perpendicular shocks are presented to address the question of whether there are sufficient particles in the solar wind thermal core, modeled as either a Maxwellian or kappa- distribution, to account for the observed accelerated spectrum. Results of accelerating the theoretical upstream distribution are compared to energetic observations at 1 AU. It is shown that the particle distribution in the solar wind thermal core is sufficient to explain the accelerated particle spectrum downstream of the shock, although the shape of the downstream distribution in some cases does not follow completely the theory of diffusive shock acceleration, indicating possible additional processes at work in the shock for these cases. Results show good to excellent agreement between the theoretical and observed spectral index for one third to one half of both quasi-parallel and quasi-perpendicular shocks studied herein. Coronal mass ejections occurring during periods of high solar activity surrounding solar maximum can produce shocks in excess of 3-8 shocks per day. During solar minimum, diffusive shock acceleration at shocks can generally be understood on the basis of single independent shocks and no other shock necessarily influences the diffusive shock acceleration mechanism. In this sense, diffusive shock acceleration during solar minimum may be regarded as Markovian. By contrast, diffusive shock acceleration of particles at periods of high solar activity (e.g. solar maximum) see frequent, closely spaced shocks that include the effects of particle acceleration at preceding and following shocks. Therefore, diffusive shock acceleration of particles at solar maximum cannot be modeled on the basis of diffusive shock acceleration as a single, independent shock and the process is essentially non-Markovian. A

  12. Formation, structure, and stability of MHD intermediate shocks

    International Nuclear Information System (INIS)

    Wu, C.C.

    1990-01-01

    Contrary to the usual belief that MHD intermediate shocks are extraneous, the author has recently shown by numerical solutions of dissipative MHD equations that intermediate shocks are admissible and can be formed through nonlinear wave steepening from continuous waves. In this paper, the formation, structure and stability of intermediate shocks in dissipative MHD are considered in detail. The differences between the conventional theory and his are pointed out and clarified. He shows that all four types of intermediate shocks can be formed from smooth waves. He also shows that there are free parameters in the structure of the intermediate shocks, and that these parameters are related to the shock stability. In addition, he shows that a rotational discontinuity can not exist with finite width, indicate how this is related to the existence of time-dependent intermediate shocks, and show why the conventional theory is not a good approximation to dissipative MHD solutions whenever there is rotation in magnetic field

  13. Universal hydrodynamic flow in holographic planar shock collisions

    Energy Technology Data Exchange (ETDEWEB)

    Chesler, Paul M. [Department of Physics, Harvard University,Cambridge MA 02138 (United States); Kilbertus, Niki [Institut für Theoretische Physik, Universität Regensburg,D-93040 Regensburg (Germany); Schee, Wilke van der [Center for Theoretical Physics, MIT,Cambridge MA 02139 (United States)

    2015-11-20

    We study the collision of planar shock waves in AdS{sub 5} as a function of shock profile. In the dual field theory the shock waves describe planar sheets of energy whose collision results in the formation of a plasma which behaves hydrodynamically at late times. We find that the post-collision stress tensor near the light cone exhibits transient non-universal behavior which depends on both the shock width and the precise functional form of the shock profile. However, over a large range of shock widths, including those which yield qualitative different behavior near the future light cone, and for different shock profiles, we find universal behavior in the subsequent hydrodynamic evolution. Additionally, we compute the rapidity distribution of produced particles and find it to be well described by a Gaussian.

  14. Shock waves in luminous early-type stars

    International Nuclear Information System (INIS)

    Castor, J.I.

    1986-01-01

    Shock waves that occur in stellar atmospheres have their origin in some hydrodynamic instability of the atmosphere itself or of the stellar interior. In luminous early-type stars these two possibilities are represented by shocks due to an unstable radiatively-accelerated wind, and to shocks generated by the non-radial pulsations known to be present in many or most OB stars. This review is concerned with the structure and development of the shocks in these two cases, and especially with the mass loss that may be due specifically to the shocks. Pulsation-produced shocks are found to be very unfavorable for causing mass loss, owing to the great radiation efficiency that allows them to remain isothermal. The situation regarding radiatively-driven shocks remains unclear, awaiting detailed hydrodynamics calculations. 20 refs., 2 figs

  15. On possible structures of transverse ionizing shock waves

    International Nuclear Information System (INIS)

    Liberman, M.A.; Velikovich, A.L.

    1978-01-01

    The possible structures of ionizing shock waves propagating in gases across the magnetic field are investigated taking account of both ionization kinetics and the non-isothermality of the plasma which is formed within the shock front. It is shown that a definite factor in shaping the structure of the transverse ionizing shock wave is photo-ionization of the neutral gas across the front. The paper includes a study of the evolution of the transverse ionizing shock front with regard to photo-ionization, disclosing that a stable stationary shock structure emerges only in boundary conditions which are close to magnetohydrodynamic ones, i.e. upsilon 1 H 1 = upsilon 2 H 2 . In the case of strong transverse ionizing shock waves, when the flux of ionizing radiation across the front is great, the shock structure is obviously magnetohydrodynamic. (author)

  16. A Brief Introduction to Chinese Biological Biological

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Chinese Biological Abstracts sponsored by the Library, the Shanghai Institutes for Biological Sciences, the Biological Documentation and Information Network, all of the Chinese Academy of Sciences, commenced publication in 1987 and was initiated to provide access to the Chinese information in the field of biology.

  17. Fundamental structure of steady plastic shock waves in metals

    International Nuclear Information System (INIS)

    Molinari, A.; Ravichandran, G.

    2004-01-01

    The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic-plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of

  18. Fundamental structure of steady plastic shock waves in metals

    Science.gov (United States)

    Molinari, A.; Ravichandran, G.

    2004-02-01

    The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic-plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of

  19. Fault Detection for Automotive Shock Absorber

    Science.gov (United States)

    Hernandez-Alcantara, Diana; Morales-Menendez, Ruben; Amezquita-Brooks, Luis

    2015-11-01

    Fault detection for automotive semi-active shock absorbers is a challenge due to the non-linear dynamics and the strong influence of the disturbances such as the road profile. First obstacle for this task, is the modeling of the fault, which has been shown to be of multiplicative nature. Many of the most widespread fault detection schemes consider additive faults. Two model-based fault algorithms for semiactive shock absorber are compared: an observer-based approach and a parameter identification approach. The performance of these schemes is validated and compared using a commercial vehicle model that was experimentally validated. Early results shows that a parameter identification approach is more accurate, whereas an observer-based approach is less sensible to parametric uncertainty.

  20. Shock waves in binary oxides memristors

    Science.gov (United States)

    Tesler, Federico; Tang, Shao; Dobrosavljević, Vladimir; Rozenberg, Marcelo

    2017-09-01

    Progress of silicon based technology is nearing its physical limit, as minimum feature size of components is reaching a mere 5 nm. The resistive switching behavior of transition metal oxides and the associated memristor device is emerging as a competitive technology for next generation electronics. Significant progress has already been made in the past decade and devices are beginning to hit the market; however, it has been mainly the result of empirical trial and error. Hence, gaining theoretical insight is of essence. In the present work we report a new connection between the resistive switching and shock wave formation, a classic topic of non-linear dynamics. We argue that the profile of oxygen ions that migrate during the commutation in insulating binary oxides may form a shock wave, which propagates through a poorly conductive region of the device. We validate the scenario by means of model simulations.

  1. DISRUPTING SHOCKS IN POSTWAR GLOBAL ECONOMIC EXPANSION

    Directory of Open Access Journals (Sweden)

    Dumitru FILIPEANU

    2016-06-01

    Full Text Available The coherence of the global economic system, created by its upswing in the first postwar decades, started to crumble in the ’70s. The destabilizing shocks affected the entire world, but in an uneven manner, in different geographical areas and at different times, being felt most acutely, with devastating economic and social effects, in Third World countries. Although the developed countries were affected as well, they always had means to combat or to diminish the adverse effects of the crises, leading to "gentler" consequences. This paper focuses on four main aspects in postwar global economic expansion, namely: the ’70s – the international monetary crisis and the oil shocks; the foreign debt crisis; the Latin American debt crisis, the Asian financial crises and the current global crisis.

  2. Regular shock refraction in planar ideal MHD

    International Nuclear Information System (INIS)

    Delmont, P; Keppens, R

    2010-01-01

    We study the classical problem of planar shock refraction at an oblique density discontinuity, separating two gases at rest, in planar ideal (magneto)hydrodynamics. In the hydrodynamical case, 3 signals arise and the interface becomes Richtmyer-Meshkov unstable due to vorticity deposition on the shocked contact. In the magnetohydrodynamical case, on the other hand, when the normal component of the magnetic field does not vanish, 5 signals will arise. The interface then typically remains stable, since the Rankine-Hugoniot jump conditions in ideal MHD do not allow for vorticity deposition on a contact discontinuity. We present an exact Riemann solver based solution strategy to describe the initial self similar refraction phase. Using grid-adaptive MHD simulations, we show that after reflection from the top wall, the interface remains stable.

  3. The bactericidal effect of shock waves

    Science.gov (United States)

    Leighs, J. A.; Appleby-Thomas, G. J.; Wood, D. C.; Goff, M. J.; Hameed, A.; Hazell, P. J.

    2014-05-01

    There are a variety of theories relating to the origins of life on our home planet, some of which discuss the possibility that life may have been spread via inter-planetary bodies. There have been a number of investigations into the ability of life to withstand the likely conditions generated by asteroid impact (both contained in the impactor and buried beneath the planet surface). Previously published data regarding the ability of bacteria to survive such applied shockwaves has produced conflicting conclusions. The work presented here used an established and published technique in combination with a single stage gas gun, to shock and subsequently recover Escherichia coli populations suspended in a phosphate buffered saline solution. Peak pressure across the sample region was calculated via numerical modelling. Survival data against peak sample pressure for recovered samples is presented alongside control tests. SEM micrographs of shocked samples are presented alongside control sets to highlight key differences between cells in each case.

  4. Bubbles, shocks and elementary technical trading strategies

    Science.gov (United States)

    Fry, John

    2014-01-01

    In this paper we provide a unifying framework for a set of seemingly disparate models for bubbles, shocks and elementary technical trading strategies in financial markets. Markets operate by balancing intrinsic levels of risk and return. This seemingly simple observation is commonly over-looked by academics and practitioners alike. Our model shares its origins in statistical physics with others. However, under our approach, changes in market regime can be explicitly shown to represent a phase transition from random to deterministic behaviour in prices. This structure leads to an improved physical and econometric model. We develop models for bubbles, shocks and elementary technical trading strategies. The list of empirical applications is both interesting and topical and includes real-estate bubbles and the on-going Eurozone crisis. We close by comparing the results of our model with purely qualitative findings from the finance literature.

  5. Introduction to Plasma Dynamo, Reconnection and Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Intrator, Thomas P. [Los Alamos National Laboratory

    2012-08-30

    In our plasma universe, most of what we can observe is composed of ionized gas, or plasma. This plasma is a conducting fluid, which advects magnetic fields when it flows. Magnetic structure occurs from the smallest planetary to the largest cosmic scales. We introduce at a basic level some interesting features of non linear magnetohydrodynamics (MHD). For example, in our plasma universe, dynamo creates magnetic fields from gravitationally driven flow energy in an electrically conducting medium, and conversely magnetic reconnection annihilates magnetic field and accelerates particles. Shocks occur when flows move faster than the local velocity (sonic or Alfven speed) for the propagation of information. Both reconnection and shocks can accelerate particles, perhaps to gigantic energies, for example as observed with 10{sup 20} eV cosmic rays.

  6. Monetary Shocks in Models with Inattentive Producers.

    Science.gov (United States)

    Alvarez, Fernando E; Lippi, Francesco; Paciello, Luigi

    2016-04-01

    We study models where prices respond slowly to shocks because firms are rationally inattentive. Producers must pay a cost to observe the determinants of the current profit maximizing price, and hence observe them infrequently. To generate large real effects of monetary shocks in such a model the time between observations must be long and/or highly volatile. Previous work on rational inattentiveness has allowed for observation intervals that are either constant-but-long ( e.g . Caballero, 1989 or Reis, 2006) or volatile-but-short ( e.g . Reis's, 2006 example where observation costs are negligible), but not both. In these models, the real effects of monetary policy are small for realistic values of the duration between observations. We show that non-negligible observation costs produce both of these effects: intervals between observations are infrequent and volatile. This generates large real effects of monetary policy for realistic values of the average time between observations.

  7. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  8. Shock wave overtake measurements on cesium iodide

    International Nuclear Information System (INIS)

    Swenson, C.A.

    1986-01-01

    The luminosity of the shock front for CsI makes it an ideal material for which to measure directly sound velocities along the Hugoniot using shock wave overtake methods. In these measurements, the occurrence of melting along the Hugoniot is marked by a discontinuous decrease in the measured sound velocity. In addition, CsI is isoelectronic with xenon and is expected to begin to show metallic behavior along the Hugoniot near 0.9 Mbar. The directly-determined sound velocities and corresponding elastic moduli would be expected to be more sensitive to this transition than either Hugoniot equations of state or optical pyrometry experiments. This paper presents a brief description of the present experiments and results

  9. The bactericidal effect of shock waves

    International Nuclear Information System (INIS)

    Leighs, J A; Appleby-Thomas, G J; Wood, D C; Goff, M J; Hameed, A; Hazell, P J

    2014-01-01

    There are a variety of theories relating to the origins of life on our home planet, some of which discuss the possibility that life may have been spread via inter-planetary bodies. There have been a number of investigations into the ability of life to withstand the likely conditions generated by asteroid impact (both contained in the impactor and buried beneath the planet surface). Previously published data regarding the ability of bacteria to survive such applied shockwaves has produced conflicting conclusions. The work presented here used an established and published technique in combination with a single stage gas gun, to shock and subsequently recover Escherichia coli populations suspended in a phosphate buffered saline solution. Peak pressure across the sample region was calculated via numerical modelling. Survival data against peak sample pressure for recovered samples is presented alongside control tests. SEM micrographs of shocked samples are presented alongside control sets to highlight key differences between cells in each case

  10. Cardiogenic shock following blunt chest trauma

    Directory of Open Access Journals (Sweden)

    Rodríguez-González Fayna

    2010-01-01

    Full Text Available Cardiac contusion, usually caused by blunt chest trauma, has been recognized with increased frequency over the past decades. Traffic accidents are the most frequent cause of cardiac contusions resulting from a direct blow to the chest. Other causes of blunt cardiac injury are numerous and include violent fall impacts, interpersonal aggression, explosions, and various types of high-risk sports. Myocardial contusion is difficult to diagnose; clinical presentation varies greatly, ranging from lack of symptoms to cardiogenic shock and arrhythmia. Although death is rare, cardiac contusion can be fatal. We present a case of cardiac contusion due to blunt chest trauma secondary to a fall impact, which manifested as cardiogenic shock.

  11. Thermal shock problems in a plate

    International Nuclear Information System (INIS)

    Takeuti, Y.; Furukawa, T.

    1981-01-01

    The problems considered are coupled dynamic thermoelastic analysis in a plate. First we try to examine a problem of the coupled dynamic thermal stress problem with small time approximation for the finite region. Next, we treatise both effects individually by pursuing rigorous anaylsis without small time approximation. Finally we consider thermal shock problems in a plate against different values of heat transfer coefficient (Biot's number) for the time. In conclusion, for usual materials, the inertia effect may be disregarded in the pure thermal problems in contrast to the coupling effect which brings small lags in the temperature and thermal stress distributions. For the consideration of the maximum thermal stress problems, Manson's uncoupled quasi-static results give enough approximation to the thermal shock problems without significant error from our numerical results. The analysis is developed by the use of Laplace transforms and several useful graphical illustrations are given. (orig./HP)

  12. High pressure multiple shock response of aluminum

    International Nuclear Information System (INIS)

    Lawrence, R.J.; Asay, J.R.

    1977-01-01

    It is well known that both dynamic yield strength and rate-dependent material response exert direct influence on the development of surface and interface instabilities under conditions of strong shock loading. A detailed understanding of these phenomena is therefore an important aspect of the analysis of dynamic inertial confinement techniques which are being used in such applications as the generation of controlled thermonuclear fusion. In these types of applications the surfaces and interfaces under consideration can be subjected to cyclic loading characterized by shock pressures on the order of 100 GPa or more. It thus becomes important to understand how rate effects and material strength differ from the values observed in the low pressure regime where they are usually measured, as well as how they are altered by the loading history

  13. Shock Waves Science and Technology Library

    CERN Document Server

    2012-01-01

    This book, as a volume of the Shock Wave Science and Technology Reference Library, is primarily concerned with the fundamental theory of detonation physics in gaseous and condensed phase reactive media. The detonation process involves complex chemical reaction and fluid dynamics, accompanied by intricate effects of heat, light, electricity and magnetism - a contemporary research field that has found wide applications in propulsion and power, hazard prevention as well as military engineering. The seven extensive chapters contained in this volume are: - Chemical Equilibrium Detonation (S. Bastea and LE Fried) - Steady One-Dimensional Detonations (A Higgins) - Detonation Instability (HD Ng and F Zhang) - Dynamic Parameters of Detonation (AA Vasiliev) - Multi-Scaled Cellular Detonation (D Desbordes and HN Presles) - Condensed Matter Detonation: Theory and Practice (C Tarver) - Theory of Detonation Shock Dynamics (JB Bdzil and DS Stewart) The chapters are thematically interrelated in a systematic descriptive appro...

  14. Banking System Shocks and REIT Performance

    OpenAIRE

    Olliges, Jan-Willem; Raudszus, Malte H.; Mueller, Glenn R.

    2013-01-01

    The purpose of this study is to directly contrast the REIT market’s stock return response to bank failures versus bank bailouts. The non-negativity constraints of the GARCH model measuring risk dynamics are mitigated by the use of the EGARCH model. EGARCH accounts for non-symmetrical effects of risk adjustments in response to return shocks. Previous research shows that bank failures cause a positive abnormal return effect for REITs. This confirms the expectation that during crises, market par...

  15. Does responsive pricing smooth demand shocks?

    OpenAIRE

    Pascal, Courty; Mario, Pagliero

    2011-01-01

    Using data from a unique pricing experiment, we investigate Vickrey’s conjecture that responsive pricing can be used to smooth both predictable and unpredictable demand shocks. Our evidence shows that increasing the responsiveness of price to demand conditions reduces the magnitude of deviations in capacity utilization rates from a pre-determined target level. A 10 percent increase in price variability leads to a decrease in the variability of capacity utilization rates between...

  16. Exogenous shocks and governing energy security

    OpenAIRE

    Diriöz, Ali Oğuz

    2017-01-01

    Cataloged from PDF version of article. Thesis (Ph.D.): Bilkent University, Department of International Relations, İhsan Doğramacı Bilkent University, 2017. Includes bibliographical references (leaves 219-248). The research examines how governments maintain energy security when faced with exogenous shocks. The main focus of inquiry examines the relative influence of markets vs. geopolitics in the area of energy security using the comparative case studies of Turkey, France, and Netherl...

  17. Dissociation of NF3 in shock waves

    International Nuclear Information System (INIS)

    Breshears, W.D.; Bird, P.F.

    1978-01-01

    The thermal dissociation rate of NF 3 in mixtures of 5% and 10%NF 3 in Ar has been measured behind incident shock waves over the temperature range 1330-2000 K. Dissociation rates were determined from postshock density gradients measured by laser beam deflection. The second order rate coefficient determined for NF 3 -Ar collisions is k/sub d/=2.31 x 10 15 exp(-20500/T) cm 3 mole sec

  18. Circulatory Shock. Volume 27, Number 4, 1989

    Science.gov (United States)

    1990-02-01

    hypocalcemia in adults (12%) and children (17%). Conclusion: Hypomagnesemia is relatively common in critically ill children and should be considered...Pediatrics, Chicago, IL 60657. Acute endotoxin shock models in the adult animals have been studied far more extensively than newborn animals related in part...treated animals. CO fell and SVR then increased. Metabolic acidosis developed at 4 hrs post LPS in both groups. In contrast to adult pigs

  19. Endogenous Growth, Monetary Shocks and Nominal Rigidities

    OpenAIRE

    Annicchiarico, Barbara; Pelloni, Alessandra; Lorenza, Rossi

    2010-01-01

    We introduce endogenous growth in an otherwise standard NK model with staggered prices and wages. Some results follow: (i) monetary volatility negatively affects long-run growth; (ii) the relation between nominal volatility and growth depends on the persistence of the nominal shocks and on the Taylor rule considered; (iii) a Taylor rule with smoothing increases the negative effect of nominal volatility on mean growth.

  20. Morphological characterization of shocked porous material

    International Nuclear Information System (INIS)

    Xu Aiguo; Zhang Guangcai; Pan, X F; Zhang Ping; Zhu Jianshi

    2009-01-01

    Morphological measures are introduced to probe the complex procedure of shock wave reaction on porous material. They characterize the geometry and the topology of the pixelized map of a state variable like temperature. The relevance to thermodynamical properties of a material is revealed and various experimental conditions are simulated. Numerical results indicate that the shock wave reaction results in a complicated sequence of compressions and rarefactions in porous material. The increasing rate of the total fractional white area A roughly gives the velocity D of a compressive-wave series. When a velocity D is mentioned, the corresponding threshold contour level of the state variable, such as temperature, should also be stated. When the threshold contour level increases, D becomes smaller. The area A increases parabolically with time t during the initial period. The A(t) curve goes back to being linear in the following three cases: (i) when the porosity δ approaches 1, (ii) when the initial shock becomes stronger and (iii) when the contour level approaches the minimum value of the state variable. The area with high temperature may continue to increase even after the early compressive waves have arrived at the downstream free surface and some rarefactive waves have come back into the target body. In the case of energetic material needing a higher temperature for initiation, a higher porosity is preferred and the material may be initiated after the precursory compressive waves have scanned the entire target body. In some cases we need scattered hot spots, but in others we need connected ones. One may desire the fabrication of a porous body and choose the appropriate shock strength according to what is needed. With the Minkowski measures, the dependence on experimental conditions is reflected simply by a few coefficients. They may be used as order parameters to classify the maps of physical variables in a similar way to thermodynamic phase transitions.