WorldWideScience

Sample records for shock pressure range

  1. Equations of state and melting curve of boron carbide in the high-pressure range of shock compression

    Energy Technology Data Exchange (ETDEWEB)

    Molodets, A. M., E-mail: molodets@icp.ac.ru; Golyshev, A. A.; Shakhrai, D. V. [Russian Academy of Sciences, Institute for Problems in Chemical Physics (Russian Federation)

    2017-03-15

    We have constructed the equations of state for crystalline boron carbide B{sub 11}C (C–B–C) and its melt under high dynamic and static pressures. A kink on the shock adiabat for boron carbide has been revealed in the pressure range near 100 GPa, and the melting curve with negative curvature in the pressure range 0–120 GPa has been calculated. The results have been used for interpreting the kinks on the shock adiabat for boron carbide in the pressure range of 0–400 GPa.

  2. Refractive index of r-cut sapphire under shock pressure range 5 to 65 GPa

    International Nuclear Information System (INIS)

    Cao, Xiuxia; Li, Jiabo; Li, Jun; Li, Xuhai; Xu, Liang; Wang, Yuan; Zhu, Wenjun; Meng, Chuanmin; Zhou, Xianming

    2014-01-01

    High-pressure refractive index of optical window materials not only can provide information on electronic polarizability and band-gap structure, but also is important for velocity correction in particle-velocity measurement with laser interferometers. In this work, the refractive index of r-cut sapphire window at 1550 nm wavelength was measured under shock pressures of 5–65 GPa. The refractive index (n) decreases linearly with increasing shock density (ρ) for shock stress above the Hugoniot elastic limit (HEL): n = 2.0485 (± 0.0197) − 0.0729 (± 0.0043)ρ, while n remains nearly a constant for elastic shocks. This behavior is attributed to the transition from elastic (below HEL) to heterogeneous plastic deformation (above HEL). Based on the obtained refractive index-density relationship, polarizability of the shocked sapphire was also obtained

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

  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. Tolerance of Artemia to static and shock pressure loading

    Science.gov (United States)

    Fitzmaurice, B. C.; Appleby-Thomas, G. J.; Painter, J. D.; Ono, F.; McMillan, P. F.; Hazael, R.; Meersman, F.

    2017-10-01

    Hydrostatic and hydrodynamic pressure loading has been applied to unicellular organisms for a number of years due to interest from food technology and extremophile communities. There is also an emerging interest in the response of multicellular organisms to high pressure conditions. Artemia salina is one such organism. Previous experiments have shown a marked difference in the hatching rate of these organisms after exposure to different magnitudes of pressure, with hydrostatic tests showing hatching rates at pressures up to several GPa, compared to dynamic loading that resulted in comparatively low survival rates at lower pressure magnitudes. In order to begin to investigate the origin of this difference, the work presented here has focussed on the response of Artemia salina to (quasi) one-dimensional shock loading. Such experiments were carried out using the plate-impact technique in order to create a planar shock front. Artemia cysts were investigated in this manner along with freshly hatched larvae (nauplii). The nauplii and cysts were observed post-shock using optical microscopy to detect motility or hatching, respectively. Hatching rates of 18% were recorded at pressures reaching 1.5 GPa, as determined with the aid of numerical models. Subjecting Artemia to quasi-one-dimensional shock loading offers a way to more thoroughly explore the shock pressure ranges these organisms can survive.

  13. 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

  14. Strain measurements during pressurized thermal shock experiment

    International Nuclear Information System (INIS)

    Tarso Vida Gomes, P. de; Julio Ricardo Barreto Cruz; Tanius Rodrigues Mansur; Denis Henrique Bianchi Scaldaferri; Miguel Mattar Neto

    2005-01-01

    For the life extension of nuclear power plants, the residual life of most of their components must be evaluated along all their operating time. Concerning the reactor pressure vessel, the pressurized thermal shock (PTS) is a very important event to be considered. For better understanding the effects of this kind of event, tests are made. The approach described here consisted of building a simplified in-scale physical model of the reactor pressure vessel, submitting it to the actual operating temperature and pressure conditions and provoking a thermal shock by means of cold water flow in its external surface. To conduct such test, the Nuclear Technology Development Center (CDTN) has been conducting several studies related to PTS and has also built a laboratory that has made possible the simulation of the PTS loading conditions. Several cracks were produced in the external surface of the reactor pressure vessel model. Strain gages were fixed by means of electrical discharge welding over the cracks regions in both external and internal surfaces. The temperature was monitored in 10 points across the vessel wall. The internal pressure was manually controlled and monitored using a pressure transducer. Two PTS experiments were conducted and this paper presents the strain measurement procedures applied to the reactor pressure vessel model, during the PTS, using strain gages experimental methodology. (authors)

  15. 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 ...

  16. 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

  17. Pressurized thermal shock program sponsored by EPRI

    International Nuclear Information System (INIS)

    Stahlkopf, K.E.

    1983-01-01

    The potential for long term neutron embrittlement of reactor vessels has been recognized for a number of years. Reactor vessel thermal shock is not a new concern, but with a growing number of plants approaching their mid-lives, it is a concern that must be understood and dealt with. Recent attention has focused on the performance of vessels during overcooling transients. This concern was designated as Unresolved Safety Issue A-49 by the Nuclear Regulatory Commission in December 1981. The USNRC staff has identified eight overcooling events of concern in U.S. PWRs. The concern is currently limited to Pressurized Water Reactors. The Electric Power Research Institute (EPRI) has supported research on reactor vessel integrity for a number of years and has supported an extensive effort on reactor vessel pressurized thermal shock (PTS) over the last three years. In addition, EPRI has developed a linked set of computer codes to simulate the pressurized thermal shock transients and assess the integrity of the nuclear reactor vessels for various overcooling transients. This paper focuses on the integrated analysis approach being used by EPRI in performing such analysis. (orig.)

  18. Pressure thermal shock analysis for nuclear reactor pressure vessel

    International Nuclear Information System (INIS)

    Galik, G.; Kutis, V.; Jakubec, J.; Paulech, J.; Murin, J.

    2015-01-01

    The appearance of structural weaknesses within the reactor pressure vessel or its structural failure caused by crack formation during pressure thermal shock processes pose as a severe environmental hazard. Coolant mixing during ECC cold water injection was simulated in a detailed CFD analysis. The temperature distribution acting on the pipe wall internal surface was calculated. Although, the results show the formation of high temperature differences and intense gradients, an additional structural analysis is required to determine the possibility of structural damage from PTS. Such an analysis will be the subject of follow-up research. (authors)

  19. 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%.

  20. Electrical conductivity of hydrogen shocked to megabar pressures

    International Nuclear Information System (INIS)

    Weir, S.T.; Nellis, W.J.; Mitchell, A.C.

    1993-08-01

    The properties of ultra-high pressure hydrogen have been the subject of much experimental and theoretical study. Of particular interest is the pressure-induced insulator-to-metal transition of hydrogen which, according to recent theoretical calculations, is predicted to occur by band-overlap in the pressure range of 1.5-3.0 Mbars on the zero temperature isotherm. Extremely high pressures are required for metallization since the low-pressure band gap is about 15 eV. Recent static-pressure diamond anvil cell experiments have searched for evidence of an insulator-to-metal transition, but no conclusive evidence for such a transition has yet been supplied. Providing conclusive evidence for hydrogen metallization is difficult because no technique has yet been developed for performing static high-pressure electrical conductivity experiments at megabar pressures. The authors report here on electrical conductivity experiments performed on H 2 and D 2 multi-shocked to megabar pressures. Electrical conductivities of dense fluid hydrogen at these pressures and temperatures reached are needed for calculations of the magnetic fields of Jupiter and Saturn, the magnetic fields being generated by convective dynamos of hot, dense, semiconducting fluid hydrogen. Also, since electrical conduction at the pressure-temperature conditions being studied is due to the thermal excitation of charge carriers across the electronic band gap, these experiments yield valuable information on the width of the band gap at high densities

  1. Shock tunnel measurements of surface pressures in shock induced separated flow field using MEMS sensor array

    International Nuclear Information System (INIS)

    Sriram, R; Jagadeesh, G; Ram, S N; Hegde, G M; Nayak, M M

    2015-01-01

    Characterized not just by high Mach numbers, but also high flow total enthalpies—often accompanied by dissociation and ionization of flowing gas itself—the experimental simulation of hypersonic flows requires impulse facilities like shock tunnels. However, shock tunnel simulation imposes challenges and restrictions on the flow diagnostics, not just because of the possible extreme flow conditions, but also the short run times—typically around 1 ms. The development, calibration and application of fast response MEMS sensors for surface pressure measurements in IISc hypersonic shock tunnel HST-2, with a typical test time of 600 μs, for the complex flow field of strong (impinging) shock boundary layer interaction with separation close to the leading edge, is delineated in this paper. For Mach numbers 5.96 (total enthalpy 1.3 MJ kg −1 ) and 8.67 (total enthalpy 1.6 MJ kg −1 ), surface pressures ranging from around 200 Pa to 50 000 Pa, in various regions of the flow field, are measured using the MEMS sensors. The measurements are found to compare well with the measurements using commercial sensors. It was possible to resolve important regions of the flow field involving significant spatial gradients of pressure, with a resolution of 5 data points within 12 mm in each MEMS array, which cannot be achieved with the other commercial sensors. In particular, MEMS sensors enabled the measurement of separation pressure (at Mach 8.67) near the leading edge and the sharply varying pressure in the reattachment zone. (paper)

  2. Pressurized Thermal Shock Analysis for OPR1000 Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, P. K.; Shamim, J. A.; Gairola, A.; Suh, Kune Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-10-15

    The study provides a brief understanding of the analysis procedure and techniques using ANSYS, such as the acceptance criteria, selection and categorization of events, thermal analysis, structural analysis including fracture mechanics assessment, crack propagation and evaluation of material properties. PTS may result from instrumentation and control malfunction, inadvertent steam dump, and postulated accidents such as smallbreak (SB) LOCA, large-break (LB) LOCA, main steam line break (MSLB), feedwater line breaks and steam generator overfill. In this study our main focus is to consider only the LB LOCA due to a cold leg break of the Optimized Power Reactor 1000 MWe (OPR1000). Consideration is given as well to the emergency core cooling system (ECCS) specific sequence with the operating parameters like pressure, temperature and time sequences. The static structural and thermal analysis to investigate the effects of PTS on RPV is the main motivation of this study. Specific surface crack effects and its propagation is also considered to measure the integrity of the RPV. This study describes the procedure for pressurized thermal shock analysis due to a loss of coolant accidental condition and emergency core cooling system operation for reactor pressure vessel.. Different accidental events that cause pressurized thermal shock to nuclear RPV that can also be analyzed in the same way. Considering the limitations of low speed computer only the static analysis is conducted. The modified LBLOCA phases and simplified geometry can is utilized to analyze the effect of PTS on RPV for general understanding not for specific specialized purpose. However, by integrating the disciplines of thermal and structural analysis, and fracture mechanics analysis a clearer understanding of the total aspect of the PTS problem has resulted. By adopting the CFD, thermal hydraulics, uncertainties and risk analysis for different type of accidental conditions, events and sequences with proper

  3. Shock tubes: compressions in the low pressure chamber

    International Nuclear Information System (INIS)

    Schins, H.; Giuliani, S.

    1986-01-01

    The gas shock tube used in these experiments consists of a low pressure chamber and a high pressure chamber, divided by a metal-diaphragm-to-rupture. In contrast to the shock mode of operation, where incident and reflected shocks in the low pressure chamber are studied which occur within 3.5 ms, in this work the compression mode of operation was studied, whose maxima occur (in the low pressure chamber) about 9 ms after rupture. Theoretical analysis was done with the finite element computer code EURDYN-1M, where the computation was carried out to 30 ms

  4. Shock response of porous metals: characterization of pressure field

    International Nuclear Information System (INIS)

    Xu Aiguo; Zhang Guangcai; Hao Pengcheng; Dong Yinfeng; Wei Xijun; Zhu Jianshi

    2012-01-01

    Shock wave reaction on porous metals is numerically simulated. When the pressure threshold is low, the increasing rate of high-pressure area gives roughly the propagation velocity of the compressive waves in the porous material. and the wave front in the condensed pressure map is nearly a plane: with the increasing of pressure threshold. more low-pressure-spots appear in the high-pressure background, and neighboring spots may coalesce, consequently, the topology of the pressure Turing pattern may change. The deviation from linearity of the increasing rate of high-pressure area is a pronounced effect of porous material under shock. The stronger the initial shock, the more pronounced the porosity effects. When the initial yield of material becomes higher, the material shows more elastic behaviors and the less porous effects, compressive and tension waves propagate more quickly, and the porous material becomes less compressible. (authors)

  5. Applied pressure-dependent anisotropic grain connectivity in shock consolidated MgB{sub 2} samples

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Wataru [Graduate School of Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511 (Japan); Takenaka, Kenta [Graduate School of Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511 (Japan); Kondo, Tadashi [Graduate School of Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511 (Japan); Tamaki, Hideyuki [Graduate School of Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511 (Japan); Matsuzawa, Hidenori [Graduate School of Engineering, University of Yamanashi, Takeda 4-3-11, Kofu 400-8511 (Japan)]. E-mail: matuzawa@mx3.nns.ne.jp; Kai, Shoichiro [Advanced Materials and Process Development Group, Explosive Division, Asahi Kasei Chemicals Corporation, Oita 870-0392 (Japan); Kakimoto, Etsuji [Advanced Materials and Process Development Group, Explosive Division, Asahi Kasei Chemicals Corporation, Oita 870-0392 (Japan); Takano, Yoshihiko [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Minehara, Eisuke [FEL Laboratory, Tokai Site, Japan Atomic Energy Research Institute, Shirakata-shirane 2-4, Tokai, Ibaraki 319-1195 (Japan)

    2006-09-15

    Three different cylindrical MgB{sub 2} bulk samples were prepared by the underwater shock consolidation method in which shock waves of several GPa, generated by detonation of explosives, were applied to a metallic cylinder containing commercially available MgB{sub 2} powders with no additives. Resistivity anisotropy of the samples increased with shock pressure. The highest- and medium-pressure applied samples had finite resistivities in the radial direction for the whole temperature range down to 12 K, whereas their axial and azimuthal resistivities dropped to zero at 32-35 K. By contrast, the lowest-pressure applied sample was approximately isotropic with a normal-state resistivity of {approx}40 {mu}{omega} cm, an onset temperature of {approx}38.5 K, and a transition width of {approx}4.5 K. These extremely anisotropic properties would have resulted from the distortion of grain boundaries and grain cores, caused by the shock pressures and their repeated bouncing.

  6. 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.

  7. Shock pressure estimation in basement rocks of the Chicxulub impact crater using cathodoluminescence spectroscopy of quartz

    Science.gov (United States)

    Tomioka, N.; Tani, R.; Kayama, M.; Chang, Y.; Nishido, H.; Kaushik, D.; Rae, A.; Ferrière, L.; Gulick, S. P. S.; Morgan, J. V.

    2017-12-01

    The Chicxulub impact structure, located in the northern Yucatan Peninsula, Mexico, was drilled by the joint IODP-ICDP Expedition 364 in April-May 2016. This expedition is the first attempt to obtain materials from the topographic peak ring within the crater previously identified by seismic imaging. A continuous core was successfully recovered from the peak ring at depths between 505.7 and 1334.7 mbsf. Uplifted, fractured, and shocked granitic basement rocks forming the peak ring were found below, in the impact breccia and impact melt rock unit (747.0-1334.7 mbsf; Morgan et al. 2016). In order to constrain impact crater formation, we investigated shock pressure distribution in the peak-ring basement rocks. Thin sections of the granitic rocks were prepared at intervals of 60 m. All the samples contains shocked minerals, with quartz grains frequently showing planar deformation features (PDFs). We determined shock pressures based on the cathodoluminescence (CL) spectroscopy of quartz. The strong advantage of the CL method is its applicability to shock pressure estimation for individual grains for both quartz and diaplectic SiO2 glass with high-spatial resolution ( 1 μm) (Chang et al. 2016). CL spectra of quartz shows a blue emission band caused by shock-induced defect centers, where its intensity increases with shock pressure. A total of 108 quartz grains in ten thin sections were analyzed using a scanning electron microscope with a CL spectrometer attached (an acceleration voltage of 15 kV and a beam current of 2 nA were used). Natural quartz single crystals, which were experimentally shocked at 0-30 GPa, were used for pressure calibration. CL spectra of all the quartz grains in the basement rocks showed broad blue emission band at the wavelength range of 300-500 nm and estimated shock pressures were in the range of 15-20 GPa. The result is consistent with values obtained from PDFs analysis in quartz using the universal stage (Ferrière et al. 2017; Rae et al. 2017

  8. Spontaneous ignition of methane-air mixtures in a wide range of pressures

    NARCIS (Netherlands)

    Zhukov, VP; Sechenov, VA; Starikovskii, AY

    2003-01-01

    The ignition delay in methane-air mixtures (phi = 0.5) within the range of temperatures of 1200-1700 K and pressures of 3-450 atm behind reflected shock waves in a shock tube is measured on the basis of emission of the electron-excited OH radical (transition A(2)Sigma(+) - X(2)Pi) at the wavelength

  9. Pressurized-thermal-shock experiments with thick vessels

    International Nuclear Information System (INIS)

    Bryan, R.H.; Nanstad, R.K.; Merkle, J.G.; Robinson, G.C.; Whitman, G.D.

    1986-01-01

    Information is provided on the series of pressurized-thermal-shock experiments at the Oak Ridge National Laboratory, motivated by a concern for the behavior of flaws in reactor pressure vessels having welds or shells exhibiting low upper-shelf Charpy impact energies, approx. 68J or less

  10. Measurements of Pressure of Extracorporeal Shock Wave Lithotripter Using Pressure-Sensitive Papers

    Science.gov (United States)

    Inose, Naoto; Ide, Masao

    1993-05-01

    This paper describes measurements of pressures at the focal region of the extracorporeal shock wave lithotripter (ESWL) using pressure-sensitive papers. At the focal region of ESWL, ordinary hydrophones are quickly damaged, because of very high pressures. Recently, measurements of pressure at the focal region of ESWL using pressure-sensitive paper have been advised. Therefore, we have studied the effectiveness of pressure-sensitive papers in the measurement of high acoustic pressures at the focal region of ESWL.

  11. Laser driven shock wave experiments for equation of state studies at megabar pressures

    CERN Document Server

    Pant, H C; Senecha, V K; Bandyopadhyay, S; Rai, V N; Khare, P; Bhat, R K; Gupta, N K; Godwal, B K

    2002-01-01

    We present the results from laser driven shock wave experiments for equation of state (EOS) studies of gold metal. An Nd:YAG laser chain (2 J, 1.06 mu m wavelength, 200 ps pulse FWHM) is used to generate shocks in planar Al foils and Al + Au layered targets. The EOS of gold in the pressure range of 9-13 Mbar is obtained using the impedance matching technique. The numerical simulations performed using the one-dimensional radiation hydrodynamic code support the experimental results. The present experimental data show remarkable agreement with the existing standard EOS models and with other experimental data obtained independently using laser driven shock wave experiments.

  12. Sound velocity of tantalum under shock compression in the 18–142 GPa range

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com; Geng, Huayun; Tan, Ye; Li, Jun [National Key Laboratory of Shock Waves and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102 Mianyang, Sichuan 621999 (China)

    2015-05-14

    Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 GPa were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in this type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.

  13. Broadband Laser Ranging for Position Measurements in Shock Physics Experiments

    Science.gov (United States)

    Rhodes, Michelle; Bennett, Corey; Daykin, Edward; Younk, Patrick; Lalone, Brandon; Kostinski, Natalie

    2017-06-01

    Broadband laser ranging (BLR) is a recently developed measurement system that provides an attractive option for determining the position of shock-driven surfaces. This system uses broadband, picosecond (or femtosecond) laser pulses and a fiber interferometer to measure relative travel time to a target and to a reference mirror. The difference in travel time produces a delay difference between pulse replicas that creates a spectral beat frequency. The spectral beating is recorded in real time using a dispersive Fourier transform and an oscilloscope. BLR systems have been designed that measure position at 12.5-40 MHz with better than 100 micron accuracy over ranges greater than 10 cm. We will give an overview of the basic operating principles of these systems. Prepared by LLNL under Contract DE-AC52-07NA27344, by LANL under Contract DE-AC52-06NA25396, and by NSTec Contract DE-AC52-06NA25946.

  14. Ductile fracture estimation of reactor pressure vessel under thermal shock

    International Nuclear Information System (INIS)

    Takahashi, Jun; Sakai, Shinsuke; Okamura, Hiroyuki

    1990-01-01

    This paper presents a new scheme for the estimation of unstable ductile fracture of a reactor pressure vessel under thermal shock conditions. First, it is shown that the bending moment applied to the cracked section can be evaluated by considering the plastic deformation of the cracked section and the thermal deformation of the shell. As the contribution of the local thermal stress to the J-value is negligible, the J-value under thermal shock can be easily evaluated by using fully plastic solutions for the cracked part. Next, the phenomena of ductile fracture under thermal shock are expressed on the load-versus-displacement diagram which enables us to grasp the transient phenomena visually. In addition, several parametrical surveys are performed on the above diagram concerning the variation of (1) thermal shock conditions, (2) initial crack length, and (3) J-resistance curve (i.e. embrittlement by neutron irradiation). (author)

  15. An alternative method for performing pressurized thermal shock analysis

    International Nuclear Information System (INIS)

    Bishop, B.A.; Meyer, T.A.; Carter, R.G.; Gamble, R.M.

    1997-01-01

    This paper describes how Probability of Crack Initiation and acceptable Pressurized Thermal Shock frequency were correlated with a c and summarizes several example applications, including evaluation of potential plant modifications. Plans for an industry supported pilot-plant application of the alternative Probabilistic Fracture Mechanics method for RG 1.154 are also discussed. 9 refs, 4 figs, 1 tab

  16. An alternative method for performing pressurized thermal shock analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, B A; Meyer, T A [Westinghouse Energy Systems, Pittsburgh, PA (United States); Carter, R G [Electric Power Research Inst., Charlotte, NC (United States); Gamble, R M [Sartrex Corp., Rockville, MD (United States)

    1997-09-01

    This paper describes how Probability of Crack Initiation and acceptable Pressurized Thermal Shock frequency were correlated with a{sub c} and summarizes several example applications, including evaluation of potential plant modifications. Plans for an industry supported pilot-plant application of the alternative Probabilistic Fracture Mechanics method for RG 1.154 are also discussed. 9 refs, 4 figs, 1 tab.

  17. Generation of high pressure shocks relevant to the shock-ignition intensity regime

    Czech Academy of Sciences Publication Activity Database

    Batani, D.; Antonelli, L.; Atzeni, S.; Badziak, J.; Baffigi, F.; Chodukowski, T.; Consoli, F.; Cristoforetti, G.; De Angelis, R.; Dudžák, Roman; Folpini, G.; Giuffrida, L.; Gizzi, L.A.; Kalinowska, Z.; Koester, P.; Krouský, Eduard; Krůs, Miroslav; Labate, L.; Levato, Tadzio; Maheut, Y.; Malka, G.; Margarone, Daniele; Marocchino, A.; Nejdl, Jaroslav; Nicolai, Ph.; O’Dell, T.; Pisarczyk, T.; Renner, Oldřich; Rhee, Y.-J.; Ribeyre, X.; Richetta, M.; Rosinski, M.; Sawicka, Magdalena; Schiavi, A.; Skála, Jiří; Šmíd, Michal; Spindloe, Ch.; Ullschmied, Jiří; Velyhan, Andriy; Vinci, T.

    2014-01-01

    Roč. 21, č. 3 (2014), 032710-032710 ISSN 1070-664X R&D Projects: GA MŠk(CZ) LC528; GA MŠk LM2010014 Institutional support: RVO:61389021 ; RVO:68378271 Keywords : High-pressure shocks * shock ignition * inertial confinement fusion * PALS laser Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (FZU-D) Impact factor: 2.142, year: 2014 http://dx.doi.org/10.1063/1.4869715

  18. Comprehensive study on the pressure dependence of shock wave plasma generation under TEA CO2 laser bombardment on metal sample

    International Nuclear Information System (INIS)

    Marpaung, A.M.; Kurniawan, H.; Tjia, M.O.; Kagawa, K.

    2001-01-01

    An experimental study has been carried out on the dynamical process taking place in the plasma generated by a TEA CO 2 laser (400 mJ, 100 ns) on a zinc target when surrounded by helium gas of pressure ranging from 2 Torr to 1 atm. Plasma characteristics were examined in detail on the emission lines of Zn I 481.0 nm and He I 587.6 nm by means of an unique time-resolved spatial distribution technique in addition to an ordinary time-resolved emission measurement technique. The results reveal, for the first time, persistent shock wave characteristics in all cases throughout the entire pressure range considered. Further analysis of the data has clarified the distinct characteristics of laser plasmas generated in different ranges of gas pressure. It is concluded that three types of shock wave plasma can be identified; namely, a target shock wave plasma in the pressure range from 2 Torr to around 50 Torr; a coupling shock wave plasma in the pressure range from around 50 Torr to 200 Torr and a gas breakdown shock wave plasma in the pressure range from around 200 Torr to 1 atm. These distinct characteristics are found to be ascribable to the different extents of the gas breakdown process taking place at the different gas pressures. These results, obtained for a TEA CO 2 laser, will provide a useful basis for the analyses of plasmas induced by other lasers. (author)

  19. The elevated temperature and thermal shock fracture toughnesses of nuclear pressure vessel steel

    International Nuclear Information System (INIS)

    Hirano, Kazumi; Kobayashi, Hideo; Nakazawa, Hajime; Nara, Atsushi.

    1979-01-01

    Thermal shock experiments were conducted on nuclear pressure vessel steel A533 Grade B Class 1. Elastic-plastic fracture toughness tests were carried out within the same high temperature range of the thermal shock experiment and the relation between stretched zone width, SZW and J-integral was clarified. An elastic-plastic thermal shock fracture toughness value. J sub(tsc) was evaluated from a critical value of stretched zone width, SZW sub(tsc) at the initiation of thermal shock fracture by using the relation between SZW and J. The J sub(tsc) value was compared with elastic-plastic fracture toughness values, J sub( ic), and the difference between the J sub(tsc) and J sub( ic) values was discussed. The results obtained are summarized as follows; (1) The relation between SZW and J before the initiation of stable crack growth in fracture toughness test at a high temperature can be expressed by the following equation regardless of test temperature, SZW = 95(J/E), where E is Young's modulus. (2) Elevated temperature fracture toughness values ranging from room temperature to 400 0 C are nearly constant regardless of test temperature. It is confirmed that upper shelf fracture toughness exists. (3) Thermal shock fracture toughness is smaller than elevated temperature fracture toughness within the same high temperature range of thermal shock experiment. (author)

  20. Experimental Study on Peak Pressure of Shock Waves in Quasi-Shallow Water

    Directory of Open Access Journals (Sweden)

    Zhenxiong Wang

    2015-01-01

    Full Text Available Based on the similarity laws of the explosion, this research develops similarity requirements of the small-scale experiments of underwater explosions and establishes a regression model for peak pressure of underwater shock waves under experimental condition. Small-scale experiments are carried out with two types of media at the bottom of the water and for different water depths. The peak pressure of underwater shock waves at different measuring points is acquired. A formula consistent with the similarity law of explosions is obtained and an analysis of the regression precision of the formula confirms its accuracy. Significance experiment indicates that the influence of distance between measuring points and charge on peak pressure of underwater shock wave is the greatest and that of water depth is the least within the range of geometric parameters. An analysis of data from experiments with different media at the bottom of the water reveals an influence on the peak pressure, as the peak pressure of a shock wave in a body of water with a bottom soft mud and rocks is about 1.33 times that of the case where the bottom material is only soft mud.

  1. Investigation of shock waves in explosive blasts using fibre optic pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Watson, S [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); MacPherson, W N [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Barton, J S [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Jones, J D C [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Tyas, A [Department of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Pichugin, A V [Department of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Hindle, A [Department of Civil and Structural Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Parkes, W [Scottish Microelectronics Centre, Kings Buildings, West Mains Road, Edinburgh EH9 3JF (United Kingdom); Dunare, C [Scottish Microelectronics Centre, Kings Buildings, West Mains Road, Edinburgh EH9 3JF (United Kingdom); Stevenson, T [Scottish Microelectronics Centre, Kings Buildings, West Mains Road, Edinburgh EH9 3JF (United Kingdom)

    2005-01-01

    We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1mm{sup 2} in overall cross-section with rise times in the {mu}s regime and pressure ranges typically 600 kPa. Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Provisional results from blast tests will be presented in which up to 6 sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front.

  2. Investigation of shock waves in explosive blasts using fibre optic pressure sensors

    International Nuclear Information System (INIS)

    Watson, S; MacPherson, W N; Barton, J S; Jones, J D C; Tyas, A; Pichugin, A V; Hindle, A; Parkes, W; Dunare, C; Stevenson, T

    2005-01-01

    We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1mm 2 in overall cross-section with rise times in the μs regime and pressure ranges typically 600 kPa. Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Provisional results from blast tests will be presented in which up to 6 sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front

  3. Electric gun: a new method for generating shock pressures in excess of 1 TPa

    International Nuclear Information System (INIS)

    Steinberg, D.; Chau, H.; Dittbenner, G.; Weingart, R.

    1978-01-01

    By combining the electrically-driven, flying-plate, high-explosive initiator with well-known gas-gun technology, a novel method of generating and measuring shock pressures greater than 1 TPa has been developed. Called the electric gun, this system is competitive with laser or nuclear-driven, shock-wave, equation-of-state experiments in the 1 to 5 TPa range. Compared to those other methods, it has the advantage of simplicity, high precision, and low cost. In addition, its small size and low total energy allow it to be easily contained for experiments with toxic materials

  4. Fracture risk assessment for the pressurized water reactor pressure vessel under pressurized thermal shock events

    International Nuclear Information System (INIS)

    Chou, Hsoung-Wei; Huang, Chin-Cheng

    2016-01-01

    Highlight: • The PTS loading conditions consistent with the USNRC's new PTS rule are applied as the loading condition for a Taiwan domestic PWR. • The state-of-the-art PFM technique is employed to analyze a reactor pressure vessel. • Novel flaw model and embrittlement correlation are considered in the study. • The RT-based regression formula of NUREG-1874 was also utilized to evaluate the failure risks of RPV. • For slightly embrittled RPV, the SO-1 type PTSs play more important role than other types of PTS. - Abstract: The fracture risk of the pressurized water reactor pressure vessel of a Taiwan domestic nuclear power plant has been evaluated according to the technical basis of the U.S.NRC's new pressurized thermal shock (PTS) screening criteria. The ORNL's FAVOR code and the PNNL's flaw models were employed to perform the probabilistic fracture mechanics analysis associated with plant specific parameters of the domestic reactor pressure vessel. Meanwhile, the PTS thermal hydraulic and probabilistic risk assessment data analyzed from a similar nuclear power plant in the United States for establishing the new PTS rule were applied as the loading conditions. Besides, an RT-based regression formula derived by the U.S.NRC was also utilized to verify the through-wall cracking frequencies. It is found that the through-wall cracking of the analyzed reactor pressure vessel only occurs during the PTS events resulted from the stuck-open primary safety relief valves that later reclose, but with only an insignificant failure risk. The results indicate that the Taiwan domestic PWR pressure vessel has sufficient structural margin for the PTS attack until either the current license expiration dates or during the proposed extended operation periods.

  5. FAVOR: A new fracture mechanics code for reactor pressure vessels subjected to pressurized thermal shock

    International Nuclear Information System (INIS)

    Dickson, T.L.

    1993-01-01

    This report discusses probabilistic fracture mechanics (PFM) analysis which is a major element of the comprehensive probabilistic methodology endorsed by the NRC for evaluation of the integrity of Pressurized Water Reactor (PWR) pressure vessels subjected to pressurized-thermal-shock (PTS) transients. It is anticipated that there will be an increasing need for an improved and validated PTS PFM code which is accepted by the NRC and utilities, as more plants approach the PTS screening criteria and are required to perform plant-specific analyses. The NRC funded Heavy Section Steel Technology (HSST) Program at Oak Ridge National Laboratories is currently developing the FAVOR (Fracture Analysis of Vessels: Oak Ridge) PTS PFM code, which is intended to meet this need. The FAVOR code incorporates the most important features of both OCA-P and VISA-II and contains some new capabilities such as PFM global modeling methodology, the capability to approximate the effects of thermal streaming on circumferential flaws located inside a plume region created by fluid and thermal stratification, a library of stress intensity factor influence coefficients, generated by the NQA-1 certified ABAQUS computer code, for an adequate range of two and three dimensional inside surface flaws, the flexibility to generate a variety of output reports, and user friendliness

  6. Laser driven shock wave experiments for equation of state studies at megabar pressures

    International Nuclear Information System (INIS)

    Pant, H C; Shukla, M; Senecha, V K; Bandyopadhyay, S; Rai, V N; Khare, P; Bhat, R K; Gupta, N K; Godwal, B K

    2002-01-01

    We present the results from laser driven shock wave experiments for equation of state (EOS) studies of gold metal. An Nd:YAG laser chain (2 J, 1.06 μm wavelength, 200 ps pulse FWHM) is used to generate shocks in planar Al foils and Al + Au layered targets. The EOS of gold in the pressure range of 9-13 Mbar is obtained using the impedance matching technique. The numerical simulations performed using the one-dimensional radiation hydrodynamic code support the experimental results. The present experimental data show remarkable agreement with the existing standard EOS models and with other experimental data obtained independently using laser driven shock wave experiments

  7. Pressure and intracorporal acceleration measurements in pigs exposed to strong shock waves in a free field

    International Nuclear Information System (INIS)

    Vassout, P.; Franke, R.; Parmentier, G.; Evrard, G.; Dancer, A.

    1987-01-01

    A theoretical study on the propagation of a pressure wave in a diphasic medium, when compared to the onset mechanism of pulmonary lesions in subjects exposed to strong shock waves, shows an increase in the incident overpressure at the interface level. Using hydrophones, intracorporal pressure was measured in pigs. The authors recorded the costal wall acceleration on the side directly exposed to the shock wave and calculated the displacement of the costal wall after a shock wave passed by. These experiments were conducted for shock waves in a free field, at an overpressure peak level ranging from 26 kFPa to 380 kPa and for a first positive phase lasting 2 ms. Sensors placed in an intracorporal position detected no increase of the overpressure level for any value of the incident pressure. A comparison of the costal wall displacement, measured experimentally, relative to the theoretical displacement of the entire animal mass indicates that the largest relative displacement of the costal wall could be the origin of the pulmonary lesions found. 5 refs., 13 figs

  8. Generation of sub-gigabar-pressure shocks by a hyper-velocity impact in the collider driven by laser-induced cavity pressure

    Science.gov (United States)

    Badziak, J.; Kucharik, M.; Liska, R.

    2018-02-01

    The generation of high-pressure shocks in the newly proposed collider in which the projectile impacting a solid target is driven by the laser-induced cavity pressure acceleration (LICPA) mechanism is investigated using two-dimensional hydrodynamic simulations. The dependence of parameters of the shock generated in the target by the impact of a gold projectile on the impacted target material and the laser driver energy is examined. It is found that both in case of low-density (CH, Al) and high-density (Au, Cu) solid targets the shock pressures in the sub-Gbar range can be produced in the LICPA-driven collider with the laser energy of only a few hundreds of joules, and the laser-to-shock energy conversion efficiency can reach values of 10 - 20 %, by an order of magnitude higher than the conversion efficiencies achieved with other laser-based methods used so far.

  9. Prevention against fragile fracture in PWR pressure vessel in the presence of pressurized thermal shock

    International Nuclear Information System (INIS)

    Carmo, E.G.D. do; Oliveira, L.F.S. de; Roberty, N.C.

    1984-01-01

    A method for the determination of operational limit curves (primary pressure versus temperature) for PWR is presented. Such curves give the operators indications related to the safety status of the plant concerning the possibility of a pressurized thermal shock. The method begins by a thermal analysis for several postulated transients, followed by the determination of the thermomechanical stresses in the vessel and finally it makes use of the linear elasticity fracture mechanics. Curves are shown for a typical PWR. (Author) [pt

  10. Numerical results from a study of LiH: the proposed standard material for the high pressure shock experiment

    International Nuclear Information System (INIS)

    Rogers, F.J.

    1975-01-01

    It is proposed to send a high pressure shock wave through a layer of LiH and then into a sample of high Z-material, resulting in a reflected shock wave back into the LiH. If the Hugoniot and some reflected Hugoniots for LiH are known the EOS of the sample can be obtained from the ''impedance matching method.'' The theory and its range of validity are described

  11. Probabilistic structural integrity of reactor vessel under pressurized thermal shock

    International Nuclear Information System (INIS)

    Myung Jo Hhung; Young Hwan Choi; Hho Jung Kim; Changheui Jang

    2005-01-01

    Performed here is a comparative assessment study for the probabilistic fracture mechanics approach of the pressurized thermal shock of the reactor pressure vessel. A round robin consisting of 1 prerequisite study and 5 cases for probabilistic approaches is proposed, and all organizations interested are invited. The problems are solved and their results are compared to issue some recommendation of best practices in this area and to assure an understanding of the key parameters of this type of approach, which will be useful in the justification through a probabilistic approach for the case of a plant over-passing the screening criteria. Six participants from 3 organizations in Korea responded to the problem and their results are compiled in this study. (authors)

  12. FAVOR: A new fracture mechanics code for reactor pressure vessels subjected to pressurized thermal shock

    International Nuclear Information System (INIS)

    Dickson, T.L.

    1993-01-01

    Probabilistic fracture mechanics (PFM) analysis is a major element of the comprehensive probabilistic methodology endorsed by the Nuclear Regulatory Commission (NRC) for evaluation of the integrity of pressurized water reactor pressure vessels subjected to pressurized-thermal-shock (PTS) transients. OCA-P and VISA-II are PTS PFM computer codes that are currently referenced in Regulatory Guide 1.154 as acceptable codes for performing plant-specific analyses. These codes perform PFM analyses to estimate the increase in vessel failure probability as the vessel accumulates radiation damage over the operating life of the vessel. Experience with the application of these codes in the last few years has provided insights into areas where they could be improved. As more plants approach the PTS screening criteria and are required to perform plant-specific analyses, there will be an increasing need for an improved and validated PTS PFM code that is accepted by the NRC and utilities. The NRC funded Heavy Section Steel Technology Program (HSST) at the Oak Ridge National Laboratory is currently developing the FAVOR (Fracture Analysis of Vessels: Oak Ridge) code, which is expected to meet this need. The FAVOR code incorporates the most important features of both OCA-P and VISA-II and contains some new capabilities such as (1) a PFM global modeling methodology; (2) the calculation of the axial stress component associated with coolant streaming beneath an inlet nozzle; (3) a library of stress intensity factor influence coefficients, generated by the NQA-1 certified ABAQUS computer code, for an appropriate range of two and three dimensional inner-surface flaws; (4) the flexibility to generate a variety of output reports; and (5) enhanced user friendliness

  13. On the Existence of Shock Instabilities at Hugoniot Pressures Beyond the Minimum Volume

    Science.gov (United States)

    Heuzé, Olivier; Pain, Jean-Christophe; Salin, Gwenael

    2009-12-01

    Flow instabilities are among the main issues of ICF studies. Heterogeneities and defects of the material or the geometry are generally considered among the sources of instabilities which are strongly amplified in spherical geometries. According to the theory of D'yakov, some ranges of the Equation of State (EOS) also generate or amplify instabilities in shock waves, which can be considered among the origin of Richtmyer-Meshkov instabilities. It is well known that, on the Hugoniot curve of most materials, the volume decreases versus pressure down to a minimum and then increases with ionization towards an asymptotic value. Recent results in this range of pressure allow us to investigate now the stability conditions. The first question to raise is the possibility of existence of such instabilities. We focus here on the properties of several elements (aluminium, iron, copper) in this range of pressure to try to give a first answer to this question.

  14. UV laser-driven shock-wave experiments at ultrahigh-pressures up to 5 TPa

    Energy Technology Data Exchange (ETDEWEB)

    Cottet, F.; Hallouin, M.; Romain, J.P. (GRECO ILM, Laboratoire d' Enegetique et Detonique, ENSMA, 86 - Poitiers (France)); Fabbro, R.; Faral, B. (GRECO ILM, Laboratoire de Physique des Milieux Ionises, Ecole Polytechnique, 91 - Palaiseau (France))

    1984-11-01

    Laser-driven shock pressures up to 5 TPa at 0.26 ..mu..m wavelenth have been evaluated from measurements of shock velocity through thin metallic foils (Al, Au, Cu) by streak camera records of shock luminosity at the near face of the foil.

  15. UV laser-driven shock-wave experiments at ultrahigh-pressures up to 5 TPa

    International Nuclear Information System (INIS)

    Cottet, F.; Hallouin, M.; Romain, J.P.; Fabbro, R.; Faral, B.

    1984-01-01

    Laser-driven shock pressures up to 5 TPa at 0.26 μm wavelenth have been evaluated from measurements of shock velocity through thin metallic foils (Al, Au, Cu) by streak camera records of shock luminosity at the near face of the foil

  16. 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

  17. PNL technical review of pressurized thermal-shock issues

    International Nuclear Information System (INIS)

    Pedersen, L.T.; Apley, W.J.; Bian, S.H.; Defferding, L.J.; Morgenstern, M.H.; Pelto, P.J.; Simonen, E.P.; Simonen, F.A.; Stevens, D.L.; Taylor, T.T.

    1982-07-01

    Pacific Northwest Laboratory (PNL) was asked to develop and recommend a regulatory position that the Nuclear Regulatory Commission (NRC) should adopt regarding the ability of reactor pressure vessels to withstand the effects of pressurized thermal shock (PTS). Licensees of eight pressurized water reactors provided NRC with estimates of remaining effective full power years before corrective actions would be required to prevent an unsafe operating condition. PNL reviewed these responses and the results of supporting research and concluded that none of the eight reactors would undergo vessel failure from a PTS event before several more years of operation. Operator actions, however, were often required to terminate a PTS event before it deteriorated to the point where failure could occur. Therefore, the near-term (less than one year) recommendation is to upgrade, on a site-specific basis, operational procedures, training, and control room instrumentation. Also, uniform criteria should be developed by NRC for use during future licensee analyses. Finally, it was recommended that NRC upgrade nondestructive inspection techniques used during vessel examinations and become more involved in the evaluation of annealing requirements

  18. Shock Compression of Liquid Noble Gases to Multi-Mbar Pressures

    Science.gov (United States)

    Root, Seth

    2011-10-01

    The high pressure - high temperature behavior of noble gases is of considerable interest because of their use in z-pinch liners for fusion studies and for understanding astrophysical and planetary evolution. However, our understanding of the equation of state (EOS) of the noble gases at extreme conditions is limited. A prime example of this is the liquid xenon Hugoniot. Previous EOS models rapidly diverged on the Hugoniot above 1 Mbar because of differences in the treatment of the electronic contribution to the free energy. Similar divergences are observed for krypton EOS. Combining shock compression experiments and density functional theory (DFT) simulations, we can determine the thermo-physical behavior of matter under extreme conditions. The experimental and DFT results have been instrumental to recent developments in planetary astrophysics and inertial confinement fusion. Shock compression experiments are performed using Sandia's Z-Accelerator to determine the Hugoniot of liquid xenon and krypton in the Mbar regime. Under strong pressure, krypton and xenon undergo an insulator to metal transition. In the metallic state, the shock front becomes reflective allowing for a direct measurement of the sample's shock velocity using laser interferometry. The Hugoniot state is determined using a Monte Carlo analysis method that accounts for systematic error in the standards and for correlations. DFT simulations at these extreme conditions show good agreement with the experimental data - demonstrating the attention to detail required for dealing with elements with relativistic core states and d-state electrons. The results from shock compression experiments and DFT simulations are presented for liquid xenon to 840 GPa and for liquid krypton to 800 GPa, decidedly increasing the range of known behavior of both gases. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company

  19. Effects of arm elevation on radial artery pressure: a new method to distinguish hypovolemic shock and septic shock from hypotension.

    Science.gov (United States)

    Xie, Zhiyi; Zhang, Zhenyu; Xu, Yuan; Zhou, Hua; Wu, Sheng; Wang, Zhong

    2018-06-01

    In this prospective observational study, we investigated the variability in radial artery invasive blood pressure associated with arm elevation in patients with different hemodynamic types. We carried out a prospective observational study using data from 73 general anesthesia hepatobiliary postoperative adult patients admitted to an ICU over a 1-year period. A standard procedure was used for the arm elevation test. The value of invasive radial arterial pressure was recorded at baseline, and 30 and 60 s after the arm had been raised from 0° to 90°. We compared the blood pressure before versus after arm elevation, and between hemodynamically stable, hypovolemic shock, and septic shock patient groups. In all 73 patients, systolic arterial pressure (SAP) decreased, diastolic arterial pressure (DAP) increased, and pulse pressure (PP) decreased at 30 and 60 s after arm elevation (Ppressure (MAP) was unchanged (P>0.05). On comparing 30 and 60 s, there was no significant difference in SAP, DAP, PP, or MAP (P>0.05). In 40 hemodynamically stable patients, SAP and PP decreased, and DAP and MAP increased significantly at 30 and 60 s after arm elevation compared with baseline (P0.05). In 17 patients with septic shock, SAP, PP, and MAP decreased significantly versus baseline at 30 and 60 s (P0.05). Comparison of the absolute value of pressure change of septic shock patients at 30 s after raising the arm showed that SAP, DAP, and MAP changes were significantly lower compared with those in hypovolemic shock and hemodynamically stable patients (Parm elevation of SAP. The best cut-off point for the SAP change value was -5 mmHg or less, with a sensitivity of 94.12%, a specificity of 80.36%, a positive likelihood ratio of 4.79 (95% CI: 2.8-8.2), and a negative likelihood ratio of 0.073 (95% CI: 0.01-0.5). Our study shows that hypovolemic shock and septic shock patients have significantly different radial artery invasive blood pressure changes in an arm elevation test

  20. The jumps of physical quantities at fast shocks under pressure anisotropy: theory versus observations at the bow shock

    International Nuclear Information System (INIS)

    Vogl, D.F.

    2000-10-01

    The interaction of the solar wind with magnetized planets leads to the formation of the so-called magnetosphere, a cavity generated by the geomagnetic field. The supersonic, superalfvenic, and magnetized solar wind flow interacting with blunt bodies produces a detached bow shock, separating the solar wind from the magnetosheath, the region between the shock wave and the magnetopause. On approach to a planetary obstacle, the solar wind becomes subsonic at the bow shock and then flows past the planet in the magnetosheath. At the bow shock, the plasma parameters and the magnetic field strength change from upstream to downstream, i.e., an increase of plasma density, temperature, pressure, and magnetic field strength, and a decrease of the velocity across the shock. In this PhD thesis we mainly concentrate on the variations of all physical quantities across the bow shock taking into account pressure anisotropy, which is an important feature in space plasma physics and observed by various spacecraft missions in the solar wind as well as in the magnetosheath. Dealing with anisotropic plasma conditions, one has to introduce the so-called pressure tensor, characterized by two scalar pressures, the pressure perpendicular (P p erp) and the pressure parallel (P p arallel) with respect to the magnetic field and in general one speaks of anisotropic conditions for P p erp is not P p arallel. Many spacecraft observations of the solar wind show P p arallel > P p erp, whereas observations of the magnetosheath show the opposite case, P p arallel p erp. Therefore, dissipation of kinetic energy into thermal energy plays an important role in studying the variations of the relevant physical quantities across the shock. It has to be mentioned that planetary bow shocks are good examples for fast MHD shock waves. Therefore, the basic equations for describing the changes across the shock can be obtained by integrating the MHD equations in conservative form. We note that these equations, the

  1. The influence of chemistry concentration on the fracture risk of a reactor pressure vessel subjected to pressurized thermal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pin-Chiun [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China); Chou, Hsoung-Wei, E-mail: hwchou@iner.gov.tw [Institute of Nuclear Energy Research, Taoyuan 32546, Taiwan, ROC (China); Ferng, Yuh-Ming [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2016-02-15

    Highlights: • Probabilistic fracture mechanics method was used to analyze a reactor pressure vessel. • Effects of copper and nickel contents on RPV fracture probability under PTS were investigated and discussed. • Representative PTS transients of Beaver Valley nuclear power plant were utilized. • The range of copper and nickel contents of the RPV materials were suggested. • With different embrittlement levels the dominated PTS category is different. - Abstract: The radiation embrittlement behavior of reactor pressure vessel shell is influenced by the chemistry concentration of metal materials. This paper aims to study the effects of copper and nickel content variations on the fracture risk of pressurized water reactor (PWR) pressure vessel subjected to pressurized thermal shock (PTS) transients. The probabilistic fracture mechanics (PFM) code, FAVOR, which was developed by the Oak Ridge National Laboratory in the United States, is employed to perform the analyses. A Taiwan domestic PWR pressure vessel assumed with varied copper and nickel contents of beltline region welds and plates is investigated in the study. Some PTS transients analyzed from Beaver Valley Unit 1 for establishing the U.S. NRC's new PTS rule are applied as the loading condition. It is found that the content variation of copper and nickel will significantly affect the radiation embrittlement and the fracture probability of PWR pressure vessels. The results can be regarded as the risk incremental factors for comparison with the safety regulation requirements on vessel degradation as well as a reference for the operation of PWR plants in Taiwan.

  2. A powerful methodology for reactor vessel pressurized thermal shock analysis

    International Nuclear Information System (INIS)

    Boucau, J.; Mager, T.

    1994-01-01

    The recent operating experience of the Pressurized Water Reactor (PWR) Industry has focused increasing attention on the issue of reactor vessel pressurized thermal shock (PTS). More specifically, the review of the old WWER-type of reactors (WWER 440/230) has indicated a sensitive behaviour to neutron embrittlement. This led already to some remedial actions including safety injection water preheating or vessel annealing. Such measures are usually taken based on the analysis of a selected number of conservative PTS events. Consideration of all postulated cooldown events would draw attention to the impact of operator action and control system effects on reactor vessel PTS. Westinghouse has developed a methodology which couples event sequence analysis with probabilistic fracture mechanics analyses, to identify those events that are of primary concern for reactor vessel integrity. Operating experience is utilized to aid in defining the appropriate event sequences and event frequencies of occurrence for the evaluation. Once the event sequences of concern are identified, detailed deterministic thermal-hydraulic and structural evaluations can be performed to determine the conditions required to minimize the extension of postulated flaws or enhance flaw arrest in the reactor vessel. The results of these analyses can then be used to better define further modifications in vessel and plant system design and to operating procedures. The purpose of the present paper will be to describe this methodology and to show its benefits for decision making. (author). 1 ref., 3 figs

  3. Integrated Software Environment for Pressurized Thermal Shock Analysis

    Directory of Open Access Journals (Sweden)

    Dino Araneo

    2011-01-01

    Full Text Available The present paper describes the main features and an application to a real Nuclear Power Plant (NPP of an Integrated Software Environment (in the following referred to as “platform” developed at University of Pisa (UNIPI to perform Pressurized Thermal Shock (PTS analysis. The platform is written in Java for the portability and it implements all the steps foreseen in the methodology developed at UNIPI for the deterministic analysis of PTS scenarios. The methodology starts with the thermal hydraulic analysis of the NPP with a system code (such as Relap5-3D and Cathare2, during a selected transient scenario. The results so obtained are then processed to provide boundary conditions for the next step, that is, a CFD calculation. Once the system pressure and the RPV wall temperature are known, the stresses inside the RPV wall can be calculated by mean a Finite Element (FE code. The last step of the methodology is the Fracture Mechanics (FM analysis, using weight functions, aimed at evaluating the stress intensity factor (KI at crack tip to be compared with the critical stress intensity factor KIc. The platform automates all these steps foreseen in the methodology once the user specifies a number of boundary conditions at the beginning of the simulation.

  4. Spatial distribution of cavitation-shock-pressure around a jet-flow gate-valve

    International Nuclear Information System (INIS)

    Oba, Risaburo; Takayama, Kazuyoshi; Ito, Yukio; Miyakura, Hideto; Nozaki, Satoru; Ishige, Tadashi; Sonoda, Shuji; Sakamoto, Kenji.

    1987-01-01

    To make clear the mechanism of cavitation erosion, the spatial distribution of cavitation shock pressures were quantitatively measured by a pressure sensitive sheet in the 1/10 scale model of a jet-flow gate-valve, for various valve-openings and cavitation numbers. The dynamic pressure response of the sheet was corrected by the shock wave generated from detonation explosives. It is made clear that the erosive shock pressures are distributed in a limited part of the whole cavitation region, and the safety region without the fatal cavitation erosion is defined. (author)

  5. Universal treatment of plumes and stresses for pressurized thermal shock evaluations

    International Nuclear Information System (INIS)

    Theofanous, T.G.; Angelini, S.; Yan, H.

    1991-01-01

    Thermally-induced stresses in a reactor pressure vessel wall, as a result of high-pressure safety injection, are an essential component of integrated risk analyses of pressurized thermal shock transients. Limiting cooldowns arise when this injection occurs under stagnated loop conditions which, in turn, correspond to a rather narrow range (in size) of small-break loss-of-coolant accidents. Moreover, at these conditions, the flow is thermally stratified, and in addition to the global cooldown, one must be concerned about the additional cooling potential due to the downcomer plumes formed by the cold streams pouring out of the cold legs. In the Nuclear Regulatory Commission's Integrated Pressurized Thermal Shock (IPTS) study, this stratification was calculated with the codes REMIX/NEWMIX. A comprehensive comparison with all available experimental data has currently been compiled. The stress analysis using this input was carried out at Oak Ridge National Laboratory using a one-dimensional approximation with the intent to conservatively bound the magnitude of thermal stresses

  6. Thermal-hydraulic analyses of pressurized-thermal-shock-induced vessel ruptures

    International Nuclear Information System (INIS)

    Dobranich, D.

    1982-05-01

    A severe overcooling transient was postulated to produce vessel wall temperatures below the nil-ductility transition temperature which in conjunction with system repressurization, led to vessel rupture at the core midplane. Such transients are referred to as pressurized-thermal-shock transients. A wide range of vessel rupture sizes were investigated to assess the emergency system's ability to cool the fuel rods. Ruptures greater than approximately 0.015 m 2 produced flows greater than those of the emergency system and resulted in core uncovery and subsequent core damage

  7. Laser-driven Mach waves for gigabar-range shock experiments

    Science.gov (United States)

    Swift, Damian; Lazicki, Amy; Coppari, Federica; Saunders, Alison; Nilsen, Joseph

    2017-10-01

    Mach reflection offers possibilities for generating planar, supported shocks at higher pressures than are practical even with laser ablation. We have studied the formation of Mach waves by algebraic solution and hydrocode simulation for drive pressures at much than reported previously, and for realistic equations of state. We predict that Mach reflection continues to occur as the drive pressure increases, and the pressure enhancement increases monotonically with drive pressure even though the ``enhancement spike'' characteristic of low-pressure Mach waves disappears. The growth angle also increases monotonically with pressure, so a higher drive pressure seems always to be an advantage. However, there are conditions where the Mach wave is perturbed by reflections. We have performed trial experiments at the Omega facility, using a laser-heated halfraum to induce a Mach wave in a polystyrene cone. Pulse length and energy limitations meant that the drive was not maintained long enough to fully support the shock, but the results indicated a Mach wave of 25-30 TPa from a drive pressure of 5-6 TPa, consistent with simulations. A similar configuration should be tested at the NIF, and a Z-pinch driven configuration may be possible. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  8. Some techniques and results from high-pressure shock-wave experiments utilizing the radiation from shocked transparent materials

    International Nuclear Information System (INIS)

    McQueen, R.G.; Fritz, J.N.

    1981-01-01

    It has been known for many years that some transparent materials emit radiation when shocked to high pressures. This property was used to determine the temperature of shocked fused and crystal quartz, which in turn allowed the thermal expansion of SiO 2 at high pressure and also the specific heat to be calculated. Once the radiative energy as a function of pressure is known for one material it is shown how this can be used to determine the temperature of other transparent materials. By the nature of the experiments very accurate shock velocities can be measured and hence high quality equation of state data obtained. Some techniques and results are presented on measuring sound velocities from symmetrical impact of nontransparent materials using radiation emitting transparent analyzers, and on nonsymmetrical impact experiments on transparent materials. Because of special requirements in the later experiments, techniques were developed that lead to very high-precision shock-wave data. Preliminary results, using these techniques are presented for making estimates of the melting region and the yield strength of some metals under strong shock conditions

  9. Pressurized thermal shock probabilistic fracture mechanics sensitivity analysis for Yankee Rowe reactor pressure vessel

    International Nuclear Information System (INIS)

    Dickson, T.L.; Cheverton, R.D.; Bryson, J.W.; Bass, B.R.; Shum, D.K.M.; Keeney, J.A.

    1993-08-01

    The Nuclear Regulatory Commission (NRC) requested Oak Ridge National Laboratory (ORNL) to perform a pressurized-thermal-shock (PTS) probabilistic fracture mechanics (PFM) sensitivity analysis for the Yankee Rowe reactor pressure vessel, for the fluences corresponding to the end of operating cycle 22, using a specific small-break-loss- of-coolant transient as the loading condition. Regions of the vessel with distinguishing features were to be treated individually -- upper axial weld, lower axial weld, circumferential weld, upper plate spot welds, upper plate regions between the spot welds, lower plate spot welds, and the lower plate regions between the spot welds. The fracture analysis methods used in the analysis of through-clad surface flaws were those contained in the established OCA-P computer code, which was developed during the Integrated Pressurized Thermal Shock (IPTS) Program. The NRC request specified that the OCA-P code be enhanced for this study to also calculate the conditional probabilities of failure for subclad flaws and embedded flaws. The results of this sensitivity analysis provide the NRC with (1) data that could be used to assess the relative influence of a number of key input parameters in the Yankee Rowe PTS analysis and (2) data that can be used for readily determining the probability of vessel failure once a more accurate indication of vessel embrittlement becomes available. This report is designated as HSST report No. 117

  10. Pressurized-thermal-shock experiments: PTSE-1 results and PTSE-2 plans

    International Nuclear Information System (INIS)

    Bryan, R.H.; Nanstad, R.K.; Wanner, R.; Merkle, J.G.; Robinson, G.C.; Whitman, G.D.

    1985-01-01

    The first pressurized-thermal-shock experiment (PTSE-1) was performed with a vessel with a 1-m-long flaw in a plug of specially tempered steel having the composition of SA-508 forging steel. The second experiment (PTSE-2) will have a similar arrangement, but the material in which the flaw will be implanted is being prepared to have low tearing resistance. Special tempering of a 2 1/4 Cr - 1 Mo steel plate has been shown to induce a low Charpy impact energy in the upper-shelf temperature range. The purpose of PTSE-2 is to investigate the fracture behavior of low-upper-shelf material in a vessel under the combined loading of concurrent pressure and thermal shock. The primary objective of the experimental plan is to induce a rapidly propagating cleavage fracture under conditions that are likely to induce a ductile tearing instability at the time of arrest of the cleavage fracture. The secondary objective of the test is to extend the range of the investigation of warm prestressing. 11 figs

  11. An integrity evaluation method of the pressure vessel of nuclear reactors under pressurized thermal shock

    International Nuclear Information System (INIS)

    Matsubara, Masaaki; Okamura, Hiroyuki.

    1987-01-01

    Present paper proposes a new algorithm of the integrity evaluation of the pressure vessel of nuclear reactors under pressurized thermal shock, PTS. This method enables us to do an effective evaluation by superimposing proposed ''PTS state-transient curves'' and ''toughness transient curves'', and is superior to a conventional one in the following points; (1) easy to get an overall view of the result of PTS event for the variations of several parameters, (2) possible to evaluate a safety margin for irradiation embrittlement, and (3) enable to construct an Expert-friendly evaluation system. In addition, the paper shows that we can execute a safety assurance test by using a flat plate model with the same thickness as that of real plant. (author)

  12. Pressurized thermal shock. Thermo-hydraulic conditions in the CNA-I reactor pressure vessel

    International Nuclear Information System (INIS)

    Ventura, Mirta A.; Rosso, Ricardo D.

    2002-01-01

    In this paper we analyze several reports issued by the Utility (Nucleo Electrica S.A.) and related to Reactor Pressure Vessel (RPV) phenomena in the CNA-I Nuclear Power Plant. These analyses are aimed at obtaining conclusions and establishing criteria ensuring the RPV integrity. Special attention was given to the effects ECCS cold-water injection at the RPV down-comer leading to pressurized thermal shock scenarios. The results deal with hypothetical primary system pipe breaks of different sizes, the inadvertent opening of the pressurizer safety valve, the double guillotine break of a live steam line in the containment and the inadvertent actuation pressurizer heaters. Modeling conditions were setup to represent experiments performed at the UPTF, under the hypothesis that they are representative of those that, hypothetically, may occur at the CNA-I. No system scaling analysis was performed, so this assertion and the inferred conclusions are no fully justified, at least in principle. The above mentioned studies, indicate that the RPV internal wall surface temperature will be nearly 40 degree. It was concluded that they allowed a better approximation of PTS phenomena in the RPV of the CNA-I. Special emphasis was made on the influence of the ECCS systems on the attained RPV wall temperature, particularly the low-pressure TJ water injection system. Some conservative hypothesis made, are discussed in this report. (author)

  13. X-ray line broadening studies on aluminum nitride, titanium carbide and titanium diboride modified by high pressure shock loading

    International Nuclear Information System (INIS)

    Morosin, B.; Graham, R.A.

    1983-01-01

    Powders of AlN, TiC and TiB 2 have been subjected to controlled shock loading with peak pressures in the samples between 14 to 27 GPa and preserved for post-shock study. Broadened x-ray diffraction peak profiles are analyzed by a simplified method and show increases in residual lattice strain and small decreases in crystallite size. Strain values range from 10 -5 to 10 -4 for TiB 2 and to values larger than 10 -3 for TiC and AlN

  14. Overview of the Integrated Pressurized Thermal-Shock (IPTS) study

    International Nuclear Information System (INIS)

    Cheverton, R.D.

    1990-01-01

    By the early 1980s, (PTS)-related, deterministic, vessel-integrity studies sponsored by the US Nuclear Regulatory Commission (NRC) indicated a potential for failure of some PWR vessels before design end of life, in the event of a postulated severe PTS transient. In response, the NRC established screening criteria, in the form of limiting values of the reference nil-ductility transition temperature (RT NDT ), and initiated the development of a probabilistic methodology for evaluating vessel integrity. This latter effort, referred to as the Integrated Pressurized Thermal-Shock (IPTS) Program, included development of techniques for postulating PTS transients, estimating their frequencies, and calculating the probability of vessel failure for a specific transient. Summing the products of frequency of transient and conditional probability of failure for each of the many postulated transients provide a calculated value of the frequency of failure. The IPTS Program also included the application of the IPTS methodology to three US PWR plants (Oconee-1, Calvert Cliffs-1, and HBRobinson-2) and the specification of a maximum permissible value of the calculated frequency of vessel failure. Another important purpose of the IPTS study was to determine, through application of the IPTS methodology, which design and operating features, parameters, and PTS transients were dominant in affecting the calculated frequency of failure. The scope of the IPTS Program included the development of a probabilistic fracture-mechanics capability, modification of the TRAC and RELAP5 thermal/hydraulic codes, and development of the methodology for estimating the uncertainty in the calculated frequency of vessel failure

  15. Reactor pressure vessel failure probability following through-wall cracks due to pressurized thermal shock events

    International Nuclear Information System (INIS)

    Simonen, F.A.; Garnich, M.R.; Simonen, E.P.; Bian, S.H.; Nomura, K.K.; Anderson, W.E.; Pedersen, L.T.

    1986-04-01

    A fracture mechanics model was developed at the Pacific Northwest Laboratory (PNL) to predict the behavior of a reactor pressure vessel following a through-wall crack that occurs during a pressurized thermal shock (PTS) event. This study, which contributed to a US Nuclear Regulatory Commission (NRC) program to study PTS risk, was coordinated with the Integrated Pressurized Thermal Shock (IPTS) Program at Oak Ridge National Laboratory (ORNL). The PNL fracture mechanics model uses the critical transients and probabilities of through-wall cracks from the IPTS Program. The PNL model predicts the arrest, reinitiation, and direction of crack growth for a postulated through-wall crack and thereby predicts the mode of vessel failure. A Monte-Carlo type of computer code was written to predict the probabilities of the alternative failure modes. This code treats the fracture mechanics properties of the various welds and plates of a vessel as random variables. Plant-specific calculations were performed for the Oconee-1, Calvert Cliffs-1, and H.B. Robinson-2 reactor pressure vessels for the conditions of postulated transients. The model predicted that 50% or more of the through-wall axial cracks will turn to follow a circumferential weld. The predicted failure mode is a complete circumferential fracture of the vessel, which results in a potential vertically directed missile consisting of the upper head assembly. Missile arrest calculations for the three nuclear plants predict that such vertical missiles, as well as all potential horizontally directed fragmentation type missiles, will be confined to the vessel enclosre cavity. The PNL failure mode model is recommended for use in future evaluations of other plants, to determine the failure modes that are most probable for postulated PTS events

  16. First all-union symposium on shock pressures, October 24-26, 1973, Moscow. Volume 2

    International Nuclear Information System (INIS)

    Batsanov, S.S.

    Twenty-two papers on the chemistry of impulsive pressures are contained in this volume. The papers deal primarily with shock wave propagation in various materials (particularly oxides) and explosive forming and sintering

  17. Contribution for the improvement of pressurized thermal shock assessment methodologies in PWR pressure vessels

    International Nuclear Information System (INIS)

    Gomes, Paulo de Tarso Vida

    2005-01-01

    The structural integrity assessment of nuclear reactor pressure vessel, concerned to Pressurized Thermal Shock (PTS) accidents, became a necessity and has been investigated since the eighty's. The recognition of the importance of PTS assessment has led the international nuclear technology community to devote a considerable research effort directed to the complete integrity assessment process of the Reactor Pressure Vessels (VPR). Researchers in Europe, Japan and U.S.A. have concentrated efforts in the VPR structural and fracture analysis, conducting experiments to best understand how specific factors act on the behavior of discontinuities, under PTS loading conditions. The main goal of this work is to study de structural behavior of an 'in scale' PWR nuclear reactor pressure vessel model, containing actual discontinuities, under loading conditions generated by a pressurized thermal shock. To construct the pressure vessel model utilized in this research, the approach developed by Barroso (1995) and based on likelihood studies, related to thermal-hydraulic behavior during the PTS was employed. To achieve the objective of this research, a new methodology to generate cracks, with known geometry and localization in the vessel model wall was developed. Additionally, an hydraulic circuit, able to flood the vessel model, heated to 300 deg C, with 10 m 3 of water at 8 deg C, in 170 seconds, was built. Thermo-hydraulic calculations using RELAP5/M0D 3.2.2γ computational code were done, to estimate the temperature profiles during the cooling time. The resulting data subsidized the thermo-structural calculations that were accomplished using ANSYS 7.01 computational code, for both 2D and 3D models. So, the stress profiles obtained with these calculations were associated with fracture mechanics concepts, to assess the crack growth behavior in the VPR model wall. After the PTS test, the VPR model was submitted to destructive and non-destructive inspections. The results

  18. Application of pressure-sensitive paint in shock-boundary layer interaction experiments

    OpenAIRE

    Seivwright, Douglas L.

    1996-01-01

    Approved for public release; distribution is unlimited A new type of pressure transducer, pressure-sensitive paint, was used to obtain pressure distributions associated with shock-boundary layer interaction. Based on the principle of photoluminescence and the process of oxygen quenching, pressure-sensitive paint provides a continous mapping of a pressure field over a surface of interest. The data measurement and acquisition system developed for use with the photoluminescence sensor was eva...

  19. Expressed sequence tags from heat-shocked seagrass Zostera noltii (Hornemann) from its southern distribution range

    NARCIS (Netherlands)

    Massa, Sonia I.; Pearson, Gareth A.; Aires, Tania; Kube, Michael; Olsen, Jeanine L.; Reinhardt, Richard; Serrao, Ester A.; Arnaud-Haond, Sophie

    Predicted global climate change threatens the distributional ranges of species worldwide. We identified genes expressed in the intertidal seagrass Zostera midi during recovery from a simulated low tide heat-shock exposure. Five Expressed Sequence Tag (EST) libraries were compared, corresponding to

  20. Safety in pipeline systems. Prevention of pressure shocks and cavitation shocks; Sichere Rohrleitungssysteme. Vermeidung von Druckstoessen und Kavitationsschlaegen

    Energy Technology Data Exchange (ETDEWEB)

    Prasser, H.-M. [Forschungszentrum Rossendorf, Dresden (Germany); Dudlik, Andreas; Schoenfeld, Sri Budi Handajani; Apostolidis, Alexander; Schlueter, Stefan [Fraunhofer-Institut UMSICHT, Oberhausen (Germany)

    2002-06-01

    The Fraunhofer institute UMSICHT, Oberhausen, and Rossendorf research centre FZR investigated the causes and consequences of pressure shocks and cavitation shocks and ways to prevent them. The experimental set-up and software tools were made available. New methods for preventing pressure shocks and cavitation shocks were developed, and armatures were developed on this basis which are also suited for retrofitting. [German] In Rohrleitungssystemen koennen durch instationaere Stroemungsvorgaenge gefaehrliche Betriebsbedingungen entstehen, die infolge von mehrfach erhoehtem Systemdruck und von Lasteintraegen in Halterungen Mensch und Umwelt erheblich schaedigen. Je nach Industriebranche koennen unterschiedliche betriebsbedingte Ursachen zu sog. Druckstoessen, Kavitations- und Kondensationsschlaegen fuehren, z.B. Kontaktkondensation von Dampf und Wasser oder ploetzliche Aenderung der Fluessigkeitsgeschwindigkeit. Das Fraunhofer-Institut UMSICHT in Oberhausen und das Forschungszentrum Rossendorf FZR untersuchen Ursachen, Folgen und Moeglichkeiten zur Vermeidung von Druckstoessen und Kavitationsschlaegen. Hierzu stehen Versuchsanlagen unterschiedlichen Massstabs sowie Softwaretools zur Verfuegung. Aus den Forschungsergebnissen wurden neue Methoden zur Vermeidung von Druckstoessen und Kavitationsschlaegen entwickelt. Hierbei werden neue oder vorhandene Absperrarmaturen mit einem hydraulischen Bremssystem ausgeruestet und mit einer Rueckschlagklappe kombiniert angeordnet. Das System gilt auch fuer bereits existierende Anlagen als besonders geeignet, da es keine Hilfsenergie benoetigt und sich an Aenderungen der Systemparameter Druck und Fliessgeschwindigkeit selbststaendig anpasst. (orig.)

  1. Effect of back-pressure forcing on shock train structures in rectangular channels

    Science.gov (United States)

    Gnani, F.; Zare-Behtash, H.; White, C.; Kontis, K.

    2018-04-01

    The deceleration of a supersonic flow to the subsonic regime inside a high-speed engine occurs through a series of shock waves, known as a shock train. The generation of such a flow structure is due to the interaction between the shock waves and the boundary layer inside a long and narrow duct. The understanding of the physics governing the shock train is vital for the improvement of the design of high-speed engines and the development of flow control strategies. The present paper analyses the sensitivity of the shock train configuration to a back-pressure variation. The complex characteristics of the shock train at an inflow Mach number M = 2 in a channel of constant height are investigated with two-dimensional RANS equations closed by the Wilcox k-ω turbulence model. Under a sinusoidal back-pressure variation, the simulated results indicate that the shock train executes a motion around its mean position that deviates from a perfect sinusoidal profile with variation in oscillation amplitude, frequency, and whether the pressure is first increased or decreased.

  2. Ozone formation in pulsed SDBD in a wide pressure range

    Science.gov (United States)

    Starikovskiy, Andrey; Nudnova, Maryia; mipt Team

    2011-10-01

    Ozone concentration in surface anode-directed DBD for wide pressure range (150 - 1300 torr) was experimentally measured. Voltage and pressure effect were investigated. Reduced electric field was measured for anode-directed and cathode-directed SDBD. E/n values in cathode-directed SDBD is higher than in cathode-directed on 50 percent at atmospheric pressure. E/n value increase leads to decrease the rate of oxygen dissociation and Ozone formation at lower pressures. Radiating region thickness of sliding discharge was measured. Typical thickness of radiating zone is 0.4-1.0 mm within pressure range 220-740 torr. It was shown that high-voltage pulsed nanosecond discharge due to high E/n value produces less Ozone with compare to other discharges. Kinetic model was proposed to describe Ozone formation in the pulsed nanosecond SDBD.

  3. Exploration of CdTe quantum dots as mesoscale pressure sensors via time-resolved shock-compression photoluminescent emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Zhitao [Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia 30332-0826 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Banishev, Alexandr A.; Christensen, James; Dlott, Dana D. [School of Chemical Sciences and Fredrick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Lee, Gyuhyon; Scripka, David A.; Breidenich, Jennifer; Summers, Christopher J.; Thadhani, Naresh N., E-mail: naresh.thadhani@mse.gatech.edu [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Xiao, Pan [LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Zhou, Min [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

    2016-07-28

    The nanometer size of CdTe quantum dots (QDs) and their unique optical properties, including size-tunable narrow photoluminescent emission, broad absorption, fast photoluminescence decay, and negligible light scattering, are ideal features for spectrally tagging the shock response of localized regions in highly heterogeneous materials such as particulate media. In this work, the time-resolved laser-excited photoluminescence response of QDs to shock-compression was investigated to explore their utilization as mesoscale sensors for pressure measurements and in situ diagnostics during shock loading experiments. Laser-driven shock-compression experiments with steady-state shock pressures ranging from 2.0 to 13 GPa were performed on nanocomposite films of CdTe QDs dispersed in a soft polyvinyl alcohol polymer matrix and in a hard inorganic sodium silicate glass matrix. Time-resolved photoluminescent emission spectroscopy was used to correlate photoluminescence changes with the history of shock pressure and the dynamics of the matrix material surrounding the QDs. The results revealed pressure-induced blueshifts in emitted wavelength, decreases in photoluminescent emission intensity, reductions in peak width, and matrix-dependent response times. Data obtained for these QD response characteristics serve as indicators for their use as possible time-resolved diagnostics of the dynamic shock-compression response of matrix materials in which such QDs are embedded as in situ sensors.

  4. Exploration of CdTe quantum dots as mesoscale pressure sensors via time-resolved shock-compression photoluminescent emission spectroscopy

    International Nuclear Information System (INIS)

    Kang, Zhitao; Banishev, Alexandr A.; Christensen, James; Dlott, Dana D.; Lee, Gyuhyon; Scripka, David A.; Breidenich, Jennifer; Summers, Christopher J.; Thadhani, Naresh N.; Xiao, Pan; Zhou, Min

    2016-01-01

    The nanometer size of CdTe quantum dots (QDs) and their unique optical properties, including size-tunable narrow photoluminescent emission, broad absorption, fast photoluminescence decay, and negligible light scattering, are ideal features for spectrally tagging the shock response of localized regions in highly heterogeneous materials such as particulate media. In this work, the time-resolved laser-excited photoluminescence response of QDs to shock-compression was investigated to explore their utilization as mesoscale sensors for pressure measurements and in situ diagnostics during shock loading experiments. Laser-driven shock-compression experiments with steady-state shock pressures ranging from 2.0 to 13 GPa were performed on nanocomposite films of CdTe QDs dispersed in a soft polyvinyl alcohol polymer matrix and in a hard inorganic sodium silicate glass matrix. Time-resolved photoluminescent emission spectroscopy was used to correlate photoluminescence changes with the history of shock pressure and the dynamics of the matrix material surrounding the QDs. The results revealed pressure-induced blueshifts in emitted wavelength, decreases in photoluminescent emission intensity, reductions in peak width, and matrix-dependent response times. Data obtained for these QD response characteristics serve as indicators for their use as possible time-resolved diagnostics of the dynamic shock-compression response of matrix materials in which such QDs are embedded as in situ sensors.

  5. Pressurized thermal shock evaluation of RPV-Stade

    International Nuclear Information System (INIS)

    Blauel, J.G.; Hodulak, L.; Siegele, D.; Nagel, G.; Hertlein, D.

    1997-01-01

    The presentation overviews the following issues: thermal shock analysis (thermohydraulics, temperatures and stresses, crack tip field parameters, cladding influence, methodology of fracture mechanics assessment); EOL safety evaluation for RPV Stade (initial conditions and input data, fracture toughness, load path diagrams, warm prestress effect, crack arrest, remaining load carrying capacity)

  6. Pressurized thermal shock evaluation of RPV-Stade

    Energy Technology Data Exchange (ETDEWEB)

    Blauel, J G; Hodulak, L; Siegele, D [Fraunhofer-Institut fuer Werkstoffmechanik, Freiburg im Breisgau (Germany); Nagel, G [PreussenElektra AG, Hannover (Germany); Hertlein, D [Siemens AG Unternehmensbereich KWU, Erlangen (Germany)

    1997-09-01

    The presentation overviews the following issues: thermal shock analysis (thermohydraulics, temperatures and stresses, crack tip field parameters, cladding influence, methodology of fracture mechanics assessment); EOL safety evaluation for RPV Stade (initial conditions and input data, fracture toughness, load path diagrams, warm prestress effect, crack arrest, remaining load carrying capacity).

  7. Variation of Pressure Waveforms in Measurements of Extracorporeal Shock Wave Lithotripter

    Science.gov (United States)

    Inose, Naoto; Ide, Masao

    1993-05-01

    In this paper, we describe measurement of variation in pressure waveforms of the acoustic field of an extra-corporeal shock-wave lithotripter (ESWL). Variations in the measured acoustic fields and pressure waveform of an underwater spark-gap-type ESWL with an exhausted spark plug electrode have been reported by researchers using crystal sensors. If the ESWL spark plugs become exhausted, patients feel pain during kidney, biliary stone disintegration. We studied the relationship between exhaustion of electrodes and the variation of pressure waveforms and shock-wave fields of the ESWL using a newly developed hydrophone.

  8. Application of large-eddy simulation to pressurized thermal shock: Assessment of the accuracy

    International Nuclear Information System (INIS)

    Loginov, M.S.; Komen, E.M.J.; Hoehne, T.

    2011-01-01

    Highlights: → We compare large-eddy simulation with experiment on the single-phase pressurized thermal shock problem. → Three test cases are considered, they cover entire range of mixing patterns. → The accuracy of the flow mixing in the reactor pressure vessel is assessed qualitatively and quantitatively. - Abstract: Pressurized Thermal Shock (PTS) is identified as one of the safety issues where Computational Fluid Dynamics (CFD) can bring real benefits. The turbulence modeling may impact overall accuracy of the calculated thermal loads on the vessel walls, therefore advanced methods for turbulent flows are required. The feasibility and mesh resolution of LES for single-phase PTS are assessed earlier in a companion paper. The current investigation deals with the accuracy of LES approach with respect to the experiment. Experimental data from the Rossendorf Coolant Mixing (ROCOM) facility is used as a basis for validation. Three test cases with different flow rates are considered. They correspond to a buoyancy-driven, a momentum-driven, and a transitional coolant mixing pattern in the downcomer. Time- and frequency-domain analysis are employed for comparison of the numerical and experimental data. The investigation shows a good qualitative prediction of the bulk flow patterns. The fluctuations are modeled correctly. A conservative estimate of the temperature drop near the wall can be obtained from the numerical results with safety factor of 1.1-1.3. In general, the current LES gives a realistic and reliable description of the considered coolant mixing experiments. The accuracy of the prediction is definitely improved with respect to earlier CFD simulations.

  9. The influence of peak shock stress on the high pressure phase transformation in Zr

    International Nuclear Information System (INIS)

    Cerreta, E K; Addessio, F L; Bronkhorst, C A; Brown, D W; Escobedo, J P; Fensin, S J; Gray, G T III; Lookman, T; Rigg, P A; Trujillo, C P

    2014-01-01

    At high pressures zirconium is known to undergo a phase transformation from the hexagonal close packed (HCP) alpha phase to the simple hexagonal omega phase. Under conditions of shock loading, a significant volume fraction of high-pressure omega phase is retained upon release. However, the hysteresis in this transformation is not well represented by equilibrium phase diagrams and the multi-phase plasticity under shock conditions is not well understood. For these reasons, the influence of peak shock stress and temperature on the retention of omega phase in Zr has been explored. VISAR and PDV measurements along with post-mortem metallographic and neutron diffraction characterization of soft recovered specimens have been utilized to quantify the volume fraction of retained omega phase and qualitatively understand the kinetics of this transformation. In turn, soft recovered specimens with varying volume fractions of retained omega phase have been utilized to understand the contribution of omega and alpha phases to strength in shock loaded Zr.

  10. Formation of omega phase under shock pressure, hydrostatic pressure and irradiation

    International Nuclear Information System (INIS)

    Dey, G.K.

    2016-01-01

    The omega transformation is one of the most intriguing phase transformations. The aspects which make it unique and interesting are the facts that this phase can form from two different parent phases viz. the alpha phase and the beta phase. The alpha to omega transformation has been observed under shock and static pressure and the mechanism involved has been studied in detail. Starting from the nucleation stage to the completion of the transformation, various interesting aspects of the mechanism of transformation has emerged in these studies. Although the parent and product phases are same under these conditions of transformation, a variation in the morphology and the kinetics of the product phase indicate different pathways for alpha to omega transformations. Similarly, the beta to omega transformation is also replete with several interesting features. This transformation can occur under application of pressure, thermal activation and also under irradiation. Here again the morphology of the product phase, the nucleation mechanisms and the kinetics of the phase transformation depend on the path of transformation, though the parent and product phases are same in each path. This presentation highlights the formation of the omega phase under different activations including the ones in extreme conditions in pure Zr and Zr based alloys. Theoretical aspects of the feasibility, pathways and kinetics of the transformations are also emphasized. (author)

  11. Structural integrity assessment of the reactor pressure vessel under the pressurized thermal shock loading

    International Nuclear Information System (INIS)

    Chen, Mingya; Lu, Feng; Wang, Rongshan; Ren, Ai

    2014-01-01

    Highlights: • The regulation and the code are proved to be conservative in the integrity assessment. • This study is helpful to understand the complex influence of the parameters. • The most dangerous case is given for the reference transient. - Abstract: Fracture mechanics analysis of pressurized thermal shock (PTS) is the key element of the integrity evaluation of the nuclear reactor pressure vessel (RPV). While the regulation of 10 CFR 50.61 and the ASME Code provide the guidance for the structural integrity, the guidance has been prepared under conservative assumptions. In this paper, the effects of conservative assumptions involved in the PTS analysis were investigated. The influence of different parameters, such as crack size, cladding effect and neutron fluence, were reviewed based on 3-D finite element analyses. Also, the sensitivity study of elastic–plastic approach, crack type and cladding thickness were reviewed. It was shown that crack depth, crack type, plastic effect and cladding thickness change the safety margin (SM) significantly, and the SM at the deepest point of the crack is not always smaller than that of the surface point, indicating that both the deepest and surface points of the crack front should be considered. For the reference transient, deeper cracks always give more conservative prediction. So compared to the prescribed analyses of a set of postulated defects with varying depths in the ASME code, it only needs to assess the crack with maximum depth in the code for the reference transient according to the conclusions

  12. Shock pressure induced by 0.44 mu m laser radiation on aluminum targets

    Czech Academy of Sciences Publication Activity Database

    Batani, D.; Stabile, H.; Ravasio, A.; Desai, T.; Lucchini, G.; Strati, F.; Ullschmied, Jiří; Krouský, Eduard; Skála, Jiří; Králiková, Božena; Pfeifer, Miroslav; Kadlec, Christelle; Mocek, Tomáš; Präg R., Ansgar; Nishimura, H.; Ochi, Y.; Kilpio, A.; Shashkov, E.; Stuchebrukhov, I.; Vovchenko, V.; Krasuyk, I.

    2003-01-01

    Roč. 21, č. 4 (2003), s. 481-487 ISSN 0263-0346 R&D Projects: GA MŠk LN00A100 Grant - others:HPRI-CT(XX) 1999-00053 Institutional research plan: CEZ:AV0Z2043910 Keywords : rear target luminosity, shock pressure, shock waves Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.646, year: 2003

  13. Creation of ultra-high-pressure shocks by the collision of laser-accelerated disks: experiment and theory

    International Nuclear Information System (INIS)

    Rosen, M.D.; Phillion, D.W.; Price, R.H.; Campbell, E.M.; Obenschain, S.P.; Whitlock, R.R.; McLean, E.A.; Ripin, B.H.

    1983-01-01

    We have used the SHIVA laser system to accelerate carbon disks to speeds in excess of 100 km/sec. The 3KJ/3 ns pulse, on a 1 mm diameter spot of a single disk produced a conventional shock of about 5 MB. The laser energy can, however, be stored in kinetic motion of this accelerated disk and delivered (reconverted to thermal energy) upon impact with another carbon disk. This collision occurs in a time much shorter than the 3 ns pulse, thus acting as a power amplifier. The shock pressures measured upon impact are estimated to be in the 20 MB range, thus demonstrating the amplification power of this colliding disk technique in creating ultra-high pressures. Theory and computer simulations of this process will be discussed, and compared with the experiment

  14. Expressed sequence tags from heat-shocked seagrass Zostera noltii (Hornemann) from its southern distribution range.

    Science.gov (United States)

    Massa, Sónia I; Pearson, Gareth A; Aires, Tânia; Kube, Michael; Olsen, Jeanine L; Reinhardt, Richard; Serrão, Ester A; Arnaud-Haond, Sophie

    2011-09-01

    Predicted global climate change threatens the distributional ranges of species worldwide. We identified genes expressed in the intertidal seagrass Zostera noltii during recovery from a simulated low tide heat-shock exposure. Five Expressed Sequence Tag (EST) libraries were compared, corresponding to four recovery times following sub-lethal temperature stress, and a non-stressed control. We sequenced and analyzed 7009 sequence reads from 30min, 2h, 4h and 24h after the beginning of the heat-shock (AHS), and 1585 from the control library, for a total of 8594 sequence reads. Among 51 Tentative UniGenes (TUGs) exhibiting significantly different expression between libraries, 19 (37.3%) were identified as 'molecular chaperones' and were over-expressed following heat-shock, while 12 (23.5%) were 'photosynthesis TUGs' generally under-expressed in heat-shocked plants. A time course analysis of expression showed a rapid increase in expression of the molecular chaperone class, most of which were heat-shock proteins; which increased from 2 sequence reads in the control library to almost 230 in the 30min AHS library, followed by a slow decrease during further recovery. In contrast, 'photosynthesis TUGs' were under-expressed 30min AHS compared with the control library, and declined progressively with recovery time in the stress libraries, with a total of 29 sequence reads 24h AHS, compared with 125 in the control. A total of 4734 TUGs were screened for EST-Single Sequence Repeats (EST-SSRs) and 86 microsatellites were identified. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Alloy synthesis using the mach stem region in an axial symmetric implosive shock: Understanding the pressure strain-temperature contributions

    Energy Technology Data Exchange (ETDEWEB)

    Staudhammer, Karl P.

    2004-01-01

    The Mach stem region in an axial symmetric shock implosion has generally been avoided in the dynamic consolidation of powders for a number of reasons. The prime reason being that the convergence of the shock waves in the cylindrical axis produce enormous pressures and concomitant temperatures that have melted tungsten. This shock wave convergence consequently results in a discontinuity in the hydro-code calculations. Dynamic deformation experiments on gold plated 304L stainless steel powders were undertaken. These experiments utilized pressures of 0.08 to 1.0 Mbar and contained a symmetric radial melt region along the central axis of the sample holder. To understand the role of deformation in a porous material, the pressure, and temperature as well as the deformation heat and associated defects must be accounted for. When the added heat of consolidation deformation exceeds the melt temperature of the 304 powders, a melt zone results that can consume large regions of the compact while still under the high-pressure pulse. As the shock wave traverses the sample and is removed in a momentum trap, its pressure/temperature are quenched. It is within this region that very high diffusion/alloying occurs and has been observed in the gold plated powders. Anomalous increases of gold diffusion into 304 stainless steel have been observed via optical microscopy, scanning electron microscopy and EDAX measurements. Values exceeding 1200 m/sec have been measured and correlated to the powder sizes, size distribution and packing density, concomitant with sample container strains ranging from 2.0% to 26%.

  16. Advanced Spectroscopic and Thermal Imaging Instrumentation for Shock Tube and Ballistic Range Facilities

    Science.gov (United States)

    Grinstead, Jay H.; Wilder, Michael C.; Reda, Daniel C.; Cruden, Brett A.; Bogdanoff, David W.

    2010-01-01

    The Electric Arc Shock Tube (EAST) facility and Hypervelocity Free Flight Aerodynamic Facility (HFFAF, an aeroballistic range) at NASA Ames support basic research in aerothermodynamic phenomena of atmospheric entry, specifically shock layer radiation spectroscopy, convective and radiative heat transfer, and transition to turbulence. Innovative optical instrumentation has been developed and implemented to meet the challenges posed from obtaining such data in these impulse facilities. Spatially and spectrally resolved measurements of absolute radiance of a travelling shock wave in EAST are acquired using multiplexed, time-gated imaging spectrographs. Nearly complete spectral coverage from the vacuum ultraviolet to the near infrared is possible in a single experiment. Time-gated thermal imaging of ballistic range models in flight enables quantitative, global measurements of surface temperature. These images can be interpreted to determine convective heat transfer rates and reveal transition to turbulence due to isolated and distributed surface roughness at hypersonic velocities. The focus of this paper is a detailed description of the optical instrumentation currently in use in the EAST and HFFAF.

  17. Acidic pH shock induces the expressions of a wide range of stress-response genes

    Directory of Open Access Journals (Sweden)

    Hong Soon-Kwang

    2008-12-01

    Full Text Available Abstract Background Environmental signals usually enhance secondary metabolite production in Streptomycetes by initiating complex signal transduction system. It is known that different sigma factors respond to different types of stresses, respectively in Streptomyces strains, which have a number of unique signal transduction mechanisms depending on the types of environmental shock. In this study, we wanted to know how a pH shock would affect the expression of various sigma factors and shock-related proteins in S. coelicolor A3(2. Results According to the results of transcriptional and proteomic analyses, the major number of sigma factor genes were upregulated by an acidic pH shock. Well-studied sigma factor genes of sigH (heat shock, sigR (oxidative stress, sigB (osmotic shock, and hrdD that play a major role in the secondary metabolism, were all strongly upregulated by the pH shock. A number of heat shock proteins including the DnaK family and chaperones such as GroEL2 were also observed to be upregulated by the pH shock, while their repressor of hspR was strongly downregulated. Oxidative stress-related proteins such as thioredoxin, catalase, superoxide dismutase, peroxidase, and osmotic shock-related protein such as vesicle synthases were also upregulated in overall. Conclusion From these observations, an acidic pH shock was considered to be one of the strongest stresses to influence a wide range of sigma factors and shock-related proteins including general stress response proteins. The upregulation of the sigma factors and shock proteins already found to be related to actinorhodin biosynthesis was considered to have contributed to enhanced actinorhodin productivity by mediating the pH shock signal to regulators or biosynthesis genes for actinorhodin production.

  18. Avoiding pressure shocks in HP blowdown lines; Vermeidung von Druckstossen in einer HD-Abschlammleitung

    Energy Technology Data Exchange (ETDEWEB)

    Stemme, R. [GESTRA AG, Bremen (Germany); Klackl, J. [EICHLER GmbH, Wien (Austria)

    2007-06-15

    Intermittent blowdown valves are installed in steam boilers as close as possible to the drum in order to avoid hydraulic pressure shocks. In the here presented case in the district heating plant Wels in Austria (gas-heated steam boiler 25 t/h 69 bar/290 C) this was not possible, and as a consequence the intermittent blowdown valves were damaged. By selecting valves suitable for this particular operating condition we have found a way to prevent pressure shocks. This example shows clearly that not only the operating data but also the right selection of the most suitable valve are of prime importance. (orig.)

  19. A Plasma Focus operated at a very low pressure range

    International Nuclear Information System (INIS)

    Bruzzone, H.; Grondona, D.; Kelly, H.; Marquez, A.

    1990-01-01

    Several characteristics of the neutron production and the hard X-ray emission from a Plasma Focus device operating at 30 kV (6 kV of stored energy) and at an unusually low pressure range are presented. (Author)

  20. Structure of dense shock-melted alkali halides: Evidence for a continuous pressure-induced structural transition in the melt

    International Nuclear Information System (INIS)

    Ross, M.; Rogers, F.J.

    1985-01-01

    Hypernetted-chain equation calculations have been made for the ion-ion pair distribution functions in shock-melted CsI, CsBr, KBr, KCl, NaCl, and LiF. The results show that the melt undergoes a gradual pressure-induced structural change from an open NaCl-like structure with six nearest neighbors of opposite charge to one that has a rare-gas close-packed-like arrangement containing about 12 neighbors of mixed charge. These effects are most pronounced for the larger ions in which the short-range repulsions are stronger relative to long-range Coulomb attractions

  1. Design of a high-pressure single pulse shock tube for chemical kinetic investigations

    International Nuclear Information System (INIS)

    Tranter, R. S.; Brezinsky, K.; Fulle, D.

    2001-01-01

    A single pulse shock tube has been designed and constructed in order to achieve extremely high pressures and temperatures to facilitate gas-phase chemical kinetic experiments. Postshock pressures of greater than 1000 atmospheres have been obtained. Temperatures greater than 1400 K have been achieved and, in principle, temperatures greater than 2000 K are easily attainable. These high temperatures and pressures permit the investigation of hydrocarbon species pyrolysis and oxidation reactions. Since these reactions occur on the time scale of 0.5--2 ms the shock tube has been constructed with an adjustable length driven section that permits variation of reaction viewing times. For any given reaction viewing time, samples can be withdrawn through a specially constructed automated sampling apparatus for subsequent species analysis with gas chromatography and mass spectrometry. The details of the design and construction that have permitted the successful generation of very high-pressure shocks in this unique apparatus are described. Additional information is provided concerning the diaphragms used in the high-pressure shock tube

  2. Electron beam generation in the fore-vacuum pressure range

    CERN Document Server

    Burachevskij, Y A; Kuzemchenko, M N; Mytnikov, A V; Oks, E M

    2001-01-01

    One presents the results of investigations to generate electron beams within 0.01-0.1 Torr gas pressure range. To generate a beam one used a plasma source based on a hollow cathode discharge in combination with a plane accelerating gap. Peculiar features of electron emission and acceleration within the mentioned pressure range are associated with high probability of gas ionization in an accelerating gap and with generation of ion flow meeting electron beam. It results in reduction of discharge combustion intensification, as well as, in plasma concentration range. The developed design of an electron source enables to generate cylindrical beams with up to 1 A current and with up to 10 keV energy

  3. Development of solar wind shock models with tensor plasma pressure for data analysis. Final technical report, 1 Aug 1970--31 Dec 1975

    International Nuclear Information System (INIS)

    Abraham-shrauner, B.

    1975-01-01

    The development of solar wind shock models with tensor plasma pressure and the comparison of some of the shock models with the satellite data from Pioneer 6 through Pioneer 9 are reported. Theoretically, difficulties were found in non-turbulent fluid shock models for tensor pressure plasmas. For microscopic shock theories nonlinear growth caused by plasma instabilities was frequently not clearly demonstrated to lead to the formation of a shock. As a result no clear choice for a shock model for the bow shock or interplanetary tensor pressure shocks emerged

  4. Effect of the dynamic pressure on the shock wave structure in a rarefied polyatomic gas

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Shigeru, E-mail: taniguchi@stat.nitech.ac.jp; Sugiyama, Masaru, E-mail: sugiyama@nitech.ac.jp [Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Arima, Takashi, E-mail: tks@stat.nitech.ac.jp [Center for Social Contribution and Collaboration, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Ruggeri, Tommaso, E-mail: tommaso.ruggeri@unibo.it [Department of Mathematics and Research Center of Applied Mathematics (CIRAM), University of Bologna, Bologna (Italy)

    2014-01-15

    We study the shock wave structure in a rarefied polyatomic gas based on a simplified model of extended thermodynamics in which the dissipation is due only to the dynamic pressure. In this case the differential system is very simple because it is a variant of Euler system with a new scalar equation for the dynamic pressure [T. Arima, S. Taniguchi, T. Ruggeri, and M. Sugiyama, Phys. Lett. A 376, 2799–2803 (2012)]. It is shown that this theory is able to describe the three types of the shock wave structure observed in experiments: the nearly symmetric shock wave structure (Type A, small Mach number), the asymmetric structure (Type B, moderate Mach number), and the structure composed of thin and thick layers (Type C, large Mach number)

  5. Validation of the activity expansion method with ultrahigh pressure shock equations of state

    International Nuclear Information System (INIS)

    Rogers, F.J.; Young, D.A.

    1997-01-01

    Laser shock experiments have recently been used to measure the equation of state (EOS) of matter in the ultrahigh pressure region between condensed matter and a weakly coupled plasma. Some ultrahigh pressure data from nuclear-generated shocks are also available. Matter at these conditions has proven very difficult to treat theoretically. The many-body activity expansion method (ACTEX) has been used for some time to calculate EOS and opacity data in this region, for use in modeling inertial confinement fusion and stellar interior plasmas. In the present work, we carry out a detailed comparison with the available experimental data in order to validate the method. The agreement is good, showing that ACTEX adequately describes strongly shocked matter. copyright 1997 The American Physical Society

  6. Validation of the activity expansion method with ultrahigh pressure shock equations of state

    Science.gov (United States)

    Rogers, Forrest J.; Young, David A.

    1997-11-01

    Laser shock experiments have recently been used to measure the equation of state (EOS) of matter in the ultrahigh pressure region between condensed matter and a weakly coupled plasma. Some ultrahigh pressure data from nuclear-generated shocks are also available. Matter at these conditions has proven very difficult to treat theoretically. The many-body activity expansion method (ACTEX) has been used for some time to calculate EOS and opacity data in this region, for use in modeling inertial confinement fusion and stellar interior plasmas. In the present work, we carry out a detailed comparison with the available experimental data in order to validate the method. The agreement is good, showing that ACTEX adequately describes strongly shocked matter.

  7. Validation of the activity expansion method with ultrahigh pressure shock equations of state

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, F.J.; Young, D.A. [Physics Department, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    1997-11-01

    Laser shock experiments have recently been used to measure the equation of state (EOS) of matter in the ultrahigh pressure region between condensed matter and a weakly coupled plasma. Some ultrahigh pressure data from nuclear-generated shocks are also available. Matter at these conditions has proven very difficult to treat theoretically. The many-body activity expansion method (ACTEX) has been used for some time to calculate EOS and opacity data in this region, for use in modeling inertial confinement fusion and stellar interior plasmas. In the present work, we carry out a detailed comparison with the available experimental data in order to validate the method. The agreement is good, showing that ACTEX adequately describes strongly shocked matter. {copyright} {ital 1997} {ital The American Physical Society}

  8. Flexible Ferroelectric Sensors with Ultrahigh Pressure Sensitivity and Linear Response over Exceptionally Broad Pressure Range.

    Science.gov (United States)

    Lee, Youngoh; Park, Jonghwa; Cho, Soowon; Shin, Young-Eun; Lee, Hochan; Kim, Jinyoung; Myoung, Jinyoung; Cho, Seungse; Kang, Saewon; Baig, Chunggi; Ko, Hyunhyub

    2018-04-24

    Flexible pressure sensors with a high sensitivity over a broad linear range can simplify wearable sensing systems without additional signal processing for the linear output, enabling device miniaturization and low power consumption. Here, we demonstrate a flexible ferroelectric sensor with ultrahigh pressure sensitivity and linear response over an exceptionally broad pressure range based on the material and structural design of ferroelectric composites with a multilayer interlocked microdome geometry. Due to the stress concentration between interlocked microdome arrays and increased contact area in the multilayer design, the flexible ferroelectric sensors could perceive static/dynamic pressure with high sensitivity (47.7 kPa -1 , 1.3 Pa minimum detection). In addition, efficient stress distribution between stacked multilayers enables linear sensing over exceptionally broad pressure range (0.0013-353 kPa) with fast response time (20 ms) and high reliability over 5000 repetitive cycles even at an extremely high pressure of 272 kPa. Our sensor can be used to monitor diverse stimuli from a low to a high pressure range including weak gas flow, acoustic sound, wrist pulse pressure, respiration, and foot pressure with a single device.

  9. Effects of high shock pressures and pore morphology on hot spot mechanisms in HMX

    Science.gov (United States)

    Springer, H. K.; Tarver, C. M.; Bastea, S.

    2017-01-01

    The shock initiation and detonation behavior of heterogeneous solid explosives is governed by its microstructure and reactive properties. New additive manufacturing techniques offer unprecedented control of explosive microstructures previously impossible, enabling us to develop novel explosives with tailored shock sensitivity and detonation properties. Since microstructure-performance relationships are not well established for explosives, there is little material design guidance for these manufacturing techniques. In this study, we explore the effects of high shock pressures (15-38 GPa) with long shock durations and different pore morphologies on hot spot mechanisms in HMX. HMX is chosen as the model material because we have experimental data on many of the chemical-thermal-mechanical properties required for pore collapse simulations. Our simulations are performed using the multi-physics arbitrary Lagrangian Eulerian finite element hydrocode, ALE3D, with Cheetah-based models for the unreacted and the product equation-of-states. We use a temperature-dependent specific heat with the unreacted equation-of-state and a temperature-dependent viscosity model to ensure accurate shock temperatures for subsequent chemistry. The Lindemann Law model is used for shock melting in HMX. In contrast to previous pore collapse studies at lower shock pressures (≤10 GPa) in HMX and shorter post-collapse burning times, our calculations show that shock melting occurs above 15 GPa due to higher bulk heating and a prominent elongated ("jet-like") hot spot region forms at later times. The combination of the elongated, post-collapse hot spot region and the higher bulk heating with increasing pressure dramatically increases the growth rate of reaction. Our calculations show that the reaction rate, dF/dt, increases with increasing shock pressure. We decompose the reaction rate into ignition ((dF/dt)ig) and growth ((dF/dt)gr) phases to better analyze our results. We define the ignition phase

  10. Microvascular oxygen pressure in the pig intestine during haemorrhagic shock and resuscitation

    NARCIS (Netherlands)

    Sinaasappel, M.; van Iterson, M.; Ince, C.

    1999-01-01

    1. The aim of this study was to investigate the relation between microvascular and venous oxygen pressures during haemorrhagic shock and resuscitation in the pig intestine. To this end microvascular PO2 (microPO2) was measured by quenching of Pd-porphyrin phosphorescence by oxygen and validated for

  11. Interactions of Delta Shock Waves for Zero-Pressure Gas Dynamics with Energy Conservation Law

    OpenAIRE

    Wei Cai; Yanyan Zhang

    2016-01-01

    We study the interactions of delta shock waves and vacuum states for the system of conservation laws of mass, momentum, and energy in zero-pressure gas dynamics. The Riemann problems with initial data of three piecewise constant states are solved case by case, and four different configurations of Riemann solutions are constructed. Furthermore, the numerical simulations completely coinciding with theoretical analysis are shown.

  12. The probabilistic structural integrity assessment of reactor pressure vessels under pressurized thermal shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingya, E-mail: chenmingya@cgnpc.com.cn [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Lu, Feng; Wang, Rongshan; Yu, Weiwei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Wang, Donghui [State Nuclear Power Plant Service Company, 200237 Shanghai (China); Zhang, Guodong; Xue, Fei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China)

    2015-12-01

    Highlights: • The methodology and the case study of the FAVOR software were shown. • The over-conservative parameters in the DFM were shown. • The differences between the PFM and the DFM were discussed. • The limits in the current FAVOR were studied. - Abstract: The pressurized thermal shock (PTS) event poses a potentially significant challenge to the structural integrity of the reactor pressure vessel (RPV) during the long time operation (LTO). In the USA, the “screening criteria” for maximum allowable embrittlement of RPV material, which forms part of the USA regulations, is based on the probabilistic fracture mechanics (PFM). The FAVOR software developed by Oak Ridge National Laboratory (ORNL) is used to establish the regulation. As the technical basis of FAVOR is not the most widely-used and codified methodologies, such as the ASME and RCC-M codes, in most countries (with exception of the USA), proving RPV integrity under the PTS load is still based on the deterministic fracture mechanics (DFM). As the maximum nil-ductility-transition temperature (RT{sub NDT}) of the beltline material for the 54 French RPVs after 40 years operation is higher than the critical values in the IAEA-TECDOC-1627 and European NEA/CSNI/R(99)3 reports (while still obviously lower than the “screening criteria” of the USA), it may conclude that the RPV will not be able to run in the LTO based on the DFM. In the FAVOR, the newest developments of fracture mechanics are applied, such as the warm pre-stress (WPS) effect, more accurate estimation of the flaw information and less conservation of the toughness (such as the three-parameter Weibull distribution of the fracture toughness). In this paper, the FAVOR software is first applied to show both the methodology and the results of the PFM, and then the limits in the current FAVOR software (Version 6.1, which represents the baseline for re-assessing the regulation of 10 CFR 50.61), lack of the impact of the constraint effect

  13. Methodology for the investigation of ignition near hot surfaces in a high-pressure shock tube

    Science.gov (United States)

    Niegemann, P.; Fikri, M.; Wlokas, I.; Röder, M.; Schulz, C.

    2018-05-01

    Autoignition of fuel/air mixtures is a determining process in internal combustion engines. Ignition can start either homogeneously in the gas phase after compression or in the vicinity of hot surfaces. While ignition properties of commercial fuels are conventionally described by a single quantity (octane number), it is known that some fuels have a varying propensity to the two processes. We present a new experimental concept that generates well-controlled temperature inhomogeneities in the shock-heated gases of a high-pressure shock tube. A shock-heated reactive mixture is brought into contact with a heated silicon nitride ceramic glow plug. The glow-plug temperature can be set up to 1200 K, higher than the post-reflected-shock gas temperatures (650-1050 K). High-repetition-rate chemiluminescence imaging is used to localize the onset of ignition in the vicinity of the hot surface. In experiments with ethanol, the results show that in most cases under shock-heated conditions, the ignition begins inhomogeneously in the vicinity of the glow plug and is favored because of the high wall temperature. Additionally, the interaction of geometry, external heating, and gas-dynamic effects was investigated by numerical simulations of the shock wave in a non-reactive flow.

  14. Pressure measurements and an analytical model for laser-generated shock waves in solids at low irradiance

    CERN Document Server

    Romain, J P; Dayma, G; Boustie, M; Resseguier, T D; Combis, P

    2002-01-01

    Low amplitude shock waves (from 1 to 300 bar) have been generated in gold layers deposited on a quartz substrate, by laser pulses at an incident fluence from 0.4 to 4.0 J cm sup - sup 2. The quartz was used as a pressure gauge for recording the induced shock profile. At a fluence <1.4 J cm sup - sup 2 , the shock pressure does not exceed 10 bar and the shock front is followed by a tension peak typical of an absorption in solid state. An analytical model of the compression-tension process has been developed, accounting for shock pressure and shock profile evolution as a function of irradiation conditions and material properties. From this model a mechanical interpretation is given to previous observations of spalling of the irradiated target surface.

  15. Pressure measurements and an analytical model for laser-generated shock waves in solids at low irradiance

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J P [Laboratoire de Combustion et de Detonique, ENSMA, BP 40109, 86961 Futuroscope-Chasseneuil (France); Bonneau, F [Departement de Physique Theorique et Appliquee CEA/DAM Ile de France, BP 12, 91680 Bruyeres le Chatel (France); Dayma, G [Laboratoire de Combustion et de Detonique, ENSMA, BP 40109, 86961 Futuroscope-Chasseneuil (France); Boustie, M [Laboratoire de Combustion et de Detonique, ENSMA, BP 40109, 86961 Futuroscope-Chasseneuil (France); Resseguier, T de [Laboratoire de Combustion et de Detonique, ENSMA, BP 40109, 86961 Futuroscope-Chasseneuil (France); Combis, P [Departement de Physique Theorique et Appliquee CEA/DAM Ile de France, BP 12, 91680 Bruyeres le Chatel (France)

    2002-11-11

    Low amplitude shock waves (from 1 to 300 bar) have been generated in gold layers deposited on a quartz substrate, by laser pulses at an incident fluence from 0.4 to 4.0 J cm{sup -2}. The quartz was used as a pressure gauge for recording the induced shock profile. At a fluence <1.4 J cm{sup -2}, the shock pressure does not exceed 10 bar and the shock front is followed by a tension peak typical of an absorption in solid state. An analytical model of the compression-tension process has been developed, accounting for shock pressure and shock profile evolution as a function of irradiation conditions and material properties. From this model a mechanical interpretation is given to previous observations of spalling of the irradiated target surface.

  16. Pressure measurements and an analytical model for laser-generated shock waves in solids at low irradiance

    International Nuclear Information System (INIS)

    Romain, J P; Bonneau, F; Dayma, G; Boustie, M; Resseguier, T de; Combis, P

    2002-01-01

    Low amplitude shock waves (from 1 to 300 bar) have been generated in gold layers deposited on a quartz substrate, by laser pulses at an incident fluence from 0.4 to 4.0 J cm -2 . The quartz was used as a pressure gauge for recording the induced shock profile. At a fluence -2 , the shock pressure does not exceed 10 bar and the shock front is followed by a tension peak typical of an absorption in solid state. An analytical model of the compression-tension process has been developed, accounting for shock pressure and shock profile evolution as a function of irradiation conditions and material properties. From this model a mechanical interpretation is given to previous observations of spalling of the irradiated target surface

  17. Central venous pressure and shock index predict lack of hemodynamic response to volume expansion in septic shock: a prospective, observational study.

    Science.gov (United States)

    Lanspa, Michael J; Brown, Samuel M; Hirshberg, Eliotte L; Jones, Jason P; Grissom, Colin K

    2012-12-01

    Volume expansion is a common therapeutic intervention in septic shock, although patient response to the intervention is difficult to predict. Central venous pressure (CVP) and shock index have been used independently to guide volume expansion, although their use is questionable. We hypothesize that a combination of these measurements will be useful. In a prospective, observational study, patients with early septic shock received 10-mL/kg volume expansion at their treating physician's discretion after brief initial resuscitation in the emergency department. Central venous pressure and shock index were measured before volume expansion interventions. Cardiac index was measured immediately before and after the volume expansion using transthoracic echocardiography. Hemodynamic response was defined as an increase in a cardiac index of 15% or greater. Thirty-four volume expansions were observed in 25 patients. A CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less individually had a good negative predictive value (83% and 88%, respectively). Of 34 volume expansions, the combination of both a high CVP and a low shock index was extremely unlikely to elicit hemodynamic response (negative predictive value, 93%; P = .02). Volume expansion in patients with early septic shock with a CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less is unlikely to lead to an increase in cardiac index. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. An improved method to experimentally determine temperature and pressure behind laser-induced shock waves at low Mach numbers

    International Nuclear Information System (INIS)

    Hendijanifard, Mohammad; Willis, David A

    2011-01-01

    Laser-matter interactions are frequently studied by measuring the propagation of shock waves caused by the rapid laser-induced material removal. An improved method for calculating the thermo-fluid parameters behind shock waves is introduced in this work. Shock waves in ambient air, induced by pulsed Nd : YAG laser ablation of aluminium films, are measured using a shadowgraph apparatus. Normal shock solutions are applied to experimental data for shock wave positions and used to calculate pressure, temperature, and velocity behind the shock wave. Non-dimensionalizing the pressure and temperature with respect to the ambient values, the dimensionless pressure and temperature are estimated to be as high as 90 and 16, respectively, at a time of 10 ns after the ablation pulse for a laser fluence of F = 14.5 J cm -2 . The results of the normal shock solution and the Taylor-Sedov similarity solution are compared to show that the Taylor-Sedov solution under-predicts pressure when the Mach number of the shock wave is small. At a fluence of 3.1 J cm -2 , the shock wave Mach number is less than 3, and the Taylor-Sedov solution under-predicts the non-dimensional pressure by as much as 45%.

  19. A Shock Tube Study of the CO + OH Reaction Near the Low-Pressure Limit

    KAUST Repository

    Nasir, Ehson Fawad; Farooq, Aamir

    2016-01-01

    Rate coefficients for the reaction between carbon monoxide and hydroxyl radical were measured behind reflected shock waves over 700 – 1230 K and 1.2 – 9.8 bar. The temperature/pressure conditions correspond to the predicted low-pressure limit of this reaction, where the channel leading to carbon dioxide formation is dominant. The reaction rate coefficients were inferred by measuring the formation of carbon dioxide using quantum cascade laser absorption near 4.2 µm. Experiments were performed under pseudo-first order conditions with tert-butyl hydroperoxide (TBHP) as the OH precursor. Using ultraviolet laser absorption by OH radicals, the TBHP decomposition rate was measured to quantify potential facility effects under extremely dilute conditions used here. The measured CO + OH rate coefficients are provided in Arrhenius form for three different pressure ranges: kCO+OH (1.2 – 1.6 bar) = 9.14 x 10-13 exp(-1265/T) cm3 molecule-1 s-1 kCO+OH (4.3 – 5.1 bar) = 8.70 x 10-13 exp(-1156/T) cm3 molecule-1 s-1 kCO+OH (9.6 – 9.8 bar) = 7.48 x 10-13 exp(-929/T) cm3 molecule-1 s-1 The measured rate coefficients are found to be lower than the master equation modeling results by Weston et al. [J. Phys. Chem. A, 117 (2013) 821] at 819 K and in closer agreement with the expression provided by Joshi and Wang [Int. J. Chem. Kinet., 38 (2006) 57].

  20. A Shock Tube Study of the CO + OH Reaction Near the Low-Pressure Limit

    KAUST Repository

    Nasir, Ehson Fawad

    2016-05-16

    Rate coefficients for the reaction between carbon monoxide and hydroxyl radical were measured behind reflected shock waves over 700 – 1230 K and 1.2 – 9.8 bar. The temperature/pressure conditions correspond to the predicted low-pressure limit of this reaction, where the channel leading to carbon dioxide formation is dominant. The reaction rate coefficients were inferred by measuring the formation of carbon dioxide using quantum cascade laser absorption near 4.2 µm. Experiments were performed under pseudo-first order conditions with tert-butyl hydroperoxide (TBHP) as the OH precursor. Using ultraviolet laser absorption by OH radicals, the TBHP decomposition rate was measured to quantify potential facility effects under extremely dilute conditions used here. The measured CO + OH rate coefficients are provided in Arrhenius form for three different pressure ranges: kCO+OH (1.2 – 1.6 bar) = 9.14 x 10-13 exp(-1265/T) cm3 molecule-1 s-1 kCO+OH (4.3 – 5.1 bar) = 8.70 x 10-13 exp(-1156/T) cm3 molecule-1 s-1 kCO+OH (9.6 – 9.8 bar) = 7.48 x 10-13 exp(-929/T) cm3 molecule-1 s-1 The measured rate coefficients are found to be lower than the master equation modeling results by Weston et al. [J. Phys. Chem. A, 117 (2013) 821] at 819 K and in closer agreement with the expression provided by Joshi and Wang [Int. J. Chem. Kinet., 38 (2006) 57].

  1. Quantum molecular dynamics simulations of the thermophysical properties of shocked liquid ammonia for pressures up to 1.3 TPa.

    Science.gov (United States)

    Li, Dafang; Zhang, Ping; Yan, Jun

    2013-10-07

    We investigate via quantum molecular-dynamics simulations the thermophysical properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature 120,000 K. The principal Hugoniot is predicted from the wide-range equation of state, which agrees well with the available experimental measurements up to 64 GPa. Our systematic study of the structural properties demonstrates that the liquid ammonia undergoes a gradual phase transition along the Hugoniot. At about 4800 K, the system transforms into a metallic, complex mixture state consisting of NH3, N2, H2, N, and H. Furthermore, we discuss the implications for the interiors of Uranus and Neptune.

  2. The effect of hydrostatic vs. shock pressure treatment on plant seeds

    Science.gov (United States)

    Mustey, Adrian; Leighs, James; Appleby-Thomas, Gareth; Wood, David; Hazael, Rachael; McMillan, Paul; Hazell, Paul

    2013-06-01

    The hydrostatic pressure and shock response of plant seeds have both been previously investigated (primarily driven by an interest in reducing bacterial contamination of crops and the theory of panspermia respectively). However, comparisons have not previously been made between these two methods of applying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in such data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder set-up and shock compression via employment of a 50-mm bore, single stage gas gun using the flyer-plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set.

  3. The functional range of heat shock proteins to combat environmental toxicity

    International Nuclear Information System (INIS)

    Mahmood, K.; Mahmood, Q.; Pervez, A.; Nasreen, S.

    2012-01-01

    Almost all the organisms possess a system to cope with the harsh physiochemical factors of environment. Such a system is based on a group of stress genes, which show rapid responses in form of stress proteins, especially heat shock proteins, when cells are confronted with insult. Heat shock proteins are now known to express in response to variety of toxic and stress conditions including diseases. As a molecular chaperone, against cytotoxicity, these ensure the functional ability of cells by repairing the denatured proteins, cellular structures like cytoskeleton and centrosomes and processes dealing with protein synthesis are stabilized or repaired during a second stress in stress tolerant cells and organisms. In unstressed cells these play an imperative role in the synthesis and transport of normal proteins. Their role in certain diseases reveals their potential application in medical field. Certain Hsp are helpful in coping carcinogenicity caused environmental pollutants and have been suggested to have anti-apoptotic, anti stress and anti-allergic function. Their expression is tissue and species specific with respect to type, intensity and duration of a toxicant. These are developmentally regulated and help in process of differentiation and thus their abnormal regulation impairs the normal development. However, their role as bio marker in risk assessment of environmental pollution warrants further research. Due to broad functional range, therefore, present review is embracing the functional aspects of smaller and Hsp 70 families expressing in animals under toxic conditions. (author)

  4. Simplified local density model for adsorption over large pressure ranges

    International Nuclear Information System (INIS)

    Rangarajan, B.; Lira, C.T.; Subramanian, R.

    1995-01-01

    Physical adsorption of high-pressure fluids onto solids is of interest in the transportation and storage of fuel and radioactive gases; the separation and purification of lower hydrocarbons; solid-phase extractions; adsorbent regenerations using supercritical fluids; supercritical fluid chromatography; and critical point drying. A mean-field model is developed that superimposes the fluid-solid potential on a fluid equation of state to predict adsorption on a flat wall from vapor, liquid, and supercritical phases. A van der Waals-type equation of state is used to represent the fluid phase, and is simplified with a local density approximation for calculating the configurational energy of the inhomogeneous fluid. The simplified local density approximation makes the model tractable for routine calculations over wide pressure ranges. The model is capable of prediction of Type 2 and 3 subcritical isotherms for adsorption on a flat wall, and shows the characteristic cusplike behavior and crossovers seen experimentally near the fluid critical point

  5. Pressurized thermal shock analysis in German nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Stefan; Braun, Michael [TUEV NORD Nuclear, Hannover (Germany)

    2015-03-15

    For more than 30 years TUeV NORD is a competent consultant in nuclear safety is-sues giving expert third party opinion to our clients. According to the German regulations the safety against brittle fracture has to be proved for the reactor pressure vessel (RPV) and with a new level of knowledge the proof has to be continuously updated with the development in international codes and standards like ASME, BS and RCC-M. The load of the RPV is a very complex transient pressure and temperature situation. Today these loading conditions can be modeled by thermal hydraulic calculations and new experimental results much more detailed than in the construction phase of German Nuclear Power Plants in the 1980s. Therefore, the proof against brittle fracture from the construction phase had to be updated for all German Nuclear Power Plants with the new findings of the loading conditions especially for a postulated small leakage in the main coolant line. The RPV consists of ferritic base material (about 250 mm) and austenitic cladding (about 6 mm) at the inner side. The base material and the cladding have different physical properties which have to be considered temperature dependently in the cal-culations. Radiation-embrittlement effects on the material are to be respected in the fracture mechanics assessment. The regions of the RPV of special interest are the core weld, the inlet and outlet nozzle region and the flange connecting weld zone. The fracture mechanics assessment is performed for normal and abnormal operating conditions and for accidents like LOCA (Loss of Coolant Accident). In this paper the German approach to fracture mechanics assessment to brittle fracture will be discussed from the point of view of a third party organization.

  6. Effects of shock pressure on 40Ar-39Ar radiometric age determinations

    International Nuclear Information System (INIS)

    Davis, P.K.

    1977-01-01

    The relation of shock to the drop in the 40 *Ar/ 39 *Ar ratio seen at high release temperatures in some neutron-irradiated lunar samples is investigated through measurements of the 40 *Ar/ 39 *Ar ratio in gas samples released by stepwise heating of rock samples previously subjected to shock, either in the laboratory or in nature. Explosives were used to shock solid pieces and powder of a basalt from a diabase dike in Liberia to calculated pressures of 65, 150 and 270 kbar. These, an unshocked sample of the powder, two naturally shocked samples from the Brent impact crater in Canada, one unshocked sample from near the crater, and appropriate monitors were irradiated. Ar from stepwise heating was analyzed. The unshocked basalt shows a good 40 *Ar/ 39 *Ar plateau at age 198 +-9 m.y. in agreement with a previous result of 186 +- 2 m.y. The shocked samples contain varying amounts of implanted atmospheric Ar, the isotopes of which have experienced mass fractionation. This effect is small enough in four samples so that the linearity of their graphs of 39 *Ar/ 40 Ar vs 36 Ar/ 40 Ar is evidence of a plateau. The ages of these samples are then 201 +- 10, 205 +- 12 and 201 +-9 m.y. It appears that the shock has had little effect on the 40 Ar- 39 Ar age spectrum, although the release patterns of the 39 *Ar are shifted downward by the order of 200 0 C. Shock implantation of Ar was at lower shock pressure, in the presence of less Ar, and into a less porous material than previously demonstrated. The Brent Crater samples do not all show good plateaus, but do indicate an age of 420 m.y. for the crater event and 795 +- 24 m.y. for the rock formation, in agreement with previous results. None of the 40 *Ar/ 39 *Ar profiles shows a drop at high temperature, but a possible role of shock implantation of Ar is indicated in the production of this effect. Further experiments are suggested. (author)

  7. Upstream pressure variations associated with the bow shock and their effects on the magnetosphere

    International Nuclear Information System (INIS)

    Fairfield, D.H.; Baumjohann, W.; Paschmann, G.; Luehr, H.; Sibeck, D.G.

    1990-01-01

    Magnetic field enhancements and depressions on the time scales of minutes were frequently observed simultaneously by the AMPTE CCE, GOES 5, and GOES 6 spacecraft in the subsolar magnetosphere. The source of these perturbations has been detected in the high time resolution AMPTE IRM measurements of the kinetic pressure of the solar wind upstream of the bow shock. It is argued that these upstream pressure variations are not inherent in the solar wind but rather are associated with the bow shock. This conclusion follows from the facts that (1) the upstream field strength and the density associated with the perturbations are highly correlated with each other whereas these quantities tend to be anticorrelated in the undisturbed solar wind, and (2) the upstream perturbations occur within the foreshock or at its boundary. The results imply a mode of interaction between the solar wind and the magnetosphere whereby density changes produced in the foreshock subsequently convect through the bow shock and impinge on the magnetosphere. Also velocity decreases deep within the foreshock sometimes reach many tens of kilometers per second and may be associated with further pressure variations as a changing interplanetary field direction changes the foreshock geometry. Upstream pressure perturbations should create significant effects on the magnetopause and at the foot of nearby field lines that lead to the polar cusp ionosphere

  8. Experiment and numerical analysis of the NPP pressurizer auxiliary spray line submitted to large thermal shocks

    International Nuclear Information System (INIS)

    Couterot, C.; Geyer, P.; Proix, J.M.

    1994-03-01

    The pressurizer auxiliary spray line of PWR nuclear power plants may be submitted to severe temperature transients during upset conditions: a 325 deg C cold thermal shock in one second is followed by a 200 deg C hot thermal shock. For such transients, the RCC-M French design code rules that prevent the ratcheting deformation hazard are not respected for the components with thickness transition. Consequently, Electricite de France has realized twenty thermal cycles under pressure on a representative mock-up. During these tests, many temperature, strain and diametral variations were measured. No significant ratcheting deformation was detected on all components, except on the 6'' x 2'' x 6'' T-piece, where a weak progressive diameter increase was observed during a few cycles. Moreover, computations of a 2'' socket welding were made with the non linear kinematic hardening Chaboche model which also showed a weak progressive deformation behaviour. (authors). 7 figs., 7 refs

  9. Dynamics of a Pipeline under the Action of Internal Shock Pressure

    Science.gov (United States)

    Il'gamov, M. A.

    2017-11-01

    The static and dynamic bending of a pipeline in the vertical plane under the action of its own weight is considered with regard to the interaction of the internal pressure with the curvature of the axial line and the axisymmetric deformation. The pressure consists of a constant and timevarying parts and is assumed to be uniformly distributed over the entire span between the supports. The pipeline reaction to the stepwise increase in the pressure is analyzed in the case where it is possible to determine the exact solution of the problem. The initial stage of bending determined by the smallness of elastic forces as compared to the inertial forces is introduced into the consideration. At this stage, the solution is sought in the form of power series and the law of pressure variation can be arbitrary. This solution provides initial conditions for determining the further process. The duration of the inertial stage is compared with the times of sharp changes of the pressure and the shock waves in fluids. The structure parameters are determined in the case where the shock pressure is accepted only by the inertial forces in the pipeline.

  10. Interactions of Delta Shock Waves for Zero-Pressure Gas Dynamics with Energy Conservation Law

    Directory of Open Access Journals (Sweden)

    Wei Cai

    2016-01-01

    Full Text Available We study the interactions of delta shock waves and vacuum states for the system of conservation laws of mass, momentum, and energy in zero-pressure gas dynamics. The Riemann problems with initial data of three piecewise constant states are solved case by case, and four different configurations of Riemann solutions are constructed. Furthermore, the numerical simulations completely coinciding with theoretical analysis are shown.

  11. Electronic energy gap of molecular hydrogen from electrical conductivity measurements at high shock pressures

    Science.gov (United States)

    Nellis, W. J.; Mitchell, A. C.; Mccandless, P. C.; Erskine, D. J.; Weir, S. T.

    1992-01-01

    Electrical conductivities were measured for liquid D2 and H2 shock compressed to pressures of 10-20 GPa (100-200 kbar), molar volumes near 8 cu cm/mol, and calculated temperatures of 2900-4600 K. The semiconducting energy gap derived from the conductivities is 12 eV, in good agreement with recent quasi-particle calculations and with oscillator frequencies measured in diamond-anvil cells.

  12. Stochastic simulation of PWR vessel integrity for pressurized thermal shock conditions

    International Nuclear Information System (INIS)

    Jackson, P.S.; Moelling, D.S.

    1984-01-01

    A stochastic simulation methodology is presented for performing probabilistic analyses of Pressurized Water Reactor vessel integrity. Application of the methodology to vessel-specific integrity analyses is described in the context of Pressurized Thermal Shock (PTS) conditions. A Bayesian method is described for developing vessel-specific models of the density of undetected volumetric flaws from ultrasonic inservice inspection results. Uncertainty limits on the probabilistic results due to sampling errors are determined from the results of the stochastic simulation. An example is provided to illustrate the methodology

  13. Analysis of stress in reactor core vessel under effect of pressure lose shock wave

    International Nuclear Information System (INIS)

    Li Yong; Liu Baoting

    2001-01-01

    High Temperature gas cooled Reactor (HTR-10) is a modular High Temperature gas cooled Reactor of the new generation. In order to analyze the safety characteristics of its core vessel in case of large rupture accident, the transient performance of its core vessel under the effect of pressure lose shock wave is studied, and the transient pressure difference between the two sides of the core vessel and the transient stresses in the core vessel is presented in this paper, these results can be used in the safety analysis and safety design of the core vessel of HTR-10. (author)

  14. Stone comminution correlates with the average peak pressure incident on a stone during shock wave lithotripsy.

    Science.gov (United States)

    Smith, N; Zhong, P

    2012-10-11

    To investigate the roles of lithotripter shock wave (LSW) parameters and cavitation in stone comminution, a series of in vitro fragmentation experiments have been conducted in water and 1,3-butanediol (a cavitation-suppressive fluid) at a variety of acoustic field positions of an electromagnetic shock wave lithotripter. Using field mapping data and integrated parameters averaged over a circular stone holder area (R(h)=7 mm), close logarithmic correlations between the average peak pressure (P(+(avg))) incident on the stone (D=10 mm BegoStone) and comminution efficiency after 500 and 1000 shocks have been identified. Moreover, the correlations have demonstrated distinctive thresholds in P(+(avg)) (5.3 MPa and 7.6 MPa for soft and hard stones, respectively), that are required to initiate stone fragmentation independent of surrounding fluid medium and LSW dose. These observations, should they be confirmed using other shock wave lithotripters, may provide an important field parameter (i.e., P(+(avg))) to guide appropriate application of SWL in clinics, and facilitate device comparison and design improvements in future lithotripters. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Variable flaw shape analysis for a reactor vessel under pressurized thermal shock loading

    International Nuclear Information System (INIS)

    Yang, C.Y.; Bamford, W.H.

    1984-01-01

    A study has been conducted to characterize the response of semi-elliptic surface flaws to thermal shock conditions which can result from safety injection actuation in nuclear reactor vessels. A methodology was developed to predict the behavior of a flaw during sample pressurized thermal shock events. The effects of a number of key variables on the flaw propagation were studied, including fracture toughness of the material and its gradient through the thickness, irradiation effects, effects of warm prestressing, and effects of the stainless steel cladding. The results of these studies show that under thermal shock loading conditions the flaw always tends to elongate along the vessel inside surface from the initial aspect ratio. However, the flaw shape always remains finite rather than becoming continuously long, as has often been assumed in earlier analyses. The final shape and size of the flaws were found to be rather strongly dependent on the effects of warm prestressing and the distribution of neutron flux. The improved methodology results in a more accurate and more realistic treatment of flaw shape changes during thermal shock events and provides the potential for quantifying additional margins for reactor vessel integrity analyses

  16. On the low pressure shock initiation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine based plastic bonded explosives

    Science.gov (United States)

    Vandersall, Kevin S.; Tarver, Craig M.; Garcia, Frank; Chidester, Steven K.

    2010-05-01

    In large explosive and propellant charges, relatively low shock pressures on the order of 1-2 GPa impacting large volumes and lasting tens of microseconds can cause shock initiation of detonation. The pressure buildup process requires several centimeters of shock propagation before shock to detonation transition occurs. In this paper, experimentally measured run distances to detonation for lower input shock pressures are shown to be much longer than predicted by extrapolation of high shock pressure data. Run distance to detonation and embedded manganin gauge pressure histories are measured using large diameter charges of six octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) based plastic bonded explosives (PBX's): PBX 9404; LX-04; LX-07; LX-10; PBX 9501; and EDC37. The embedded gauge records show that the lower shock pressures create fewer and less energetic "hot spot" reaction sites, which consume the surrounding explosive particles at reduced reaction rates and cause longer distances to detonation. The experimental data is analyzed using the ignition and growth reactive flow model of shock initiation in solid explosives. Using minimum values of the degrees of compression required to ignite hot spot reactions, the previously determined high shock pressure ignition and growth model parameters for the six explosives accurately simulate the much longer run distances to detonation and much slower growths of pressure behind the shock fronts measured during the shock initiation of HMX PBX's at several low shock pressures.

  17. On the Unsteadiness of a Transitional Shock Wave-Boundary Layer Interaction Using Fast-Response Pressure-Sensitive Paint

    Science.gov (United States)

    Lash, E. Lara; Schmisseur, John

    2017-11-01

    Pressure-sensitive paint has been used to evaluate the unsteady dynamics of transitional and turbulent shock wave-boundary layer interactions generated by a vertical cylinder on a flat plate in a Mach 2 freestream. The resulting shock structure consists of an inviscid bow shock that bifurcates into a separation shock and trailing shock. The primary features of interest are the separation shock and an upstream influence shock that is intermittently present in transitional boundary layer interactions, but not observed in turbulent interactions. The power spectral densities, frequency peaks, and normalized wall pressures are analyzed as the incoming boundary layer state changes from transitional to fully turbulent, comparing both centerline and outboard regions of the interaction. The present study compares the scales and frequencies of the dynamics of the separation shock structure in different boundary layer regimes. Synchronized high-speed Schlieren imaging provides quantitative statistical analyses as well as qualitative comparisons to the fast-response pressure sensitive paint measurements. Materials based on research supported by the U.S. Office of Naval Research under Award Number N00014-15-1-2269.

  18. Potential effect of fracture technology on IPTS [Integrated Pressurized Thermal Shock] analysis (Fracture toughness: Kla and Klc and warm prestressing)

    International Nuclear Information System (INIS)

    Dickson, T.L.

    1990-01-01

    A major nuclear plant life extension issue to be confronted in the 1990's is pressure vessel integrity for the pressurized thermal shock (PTS) loading condition. Governing criteria associated with PTS are included in ''The PTS Rule'' (10 CFR 50.61) and Regulatory Guide 1.154: Format and Content of Plant-Specific Pressurized Thermal Shock Safety Analysis Reports for Pressurized Water Reactors. The results of the Integrated Pressurized Water Reactors. The results of the Integrated Pressurized Thermal Shock (IPTS) Program, along with risk assessments and fracture analyses performed by the NRC and reactor system vendors, contributed to the derivation of the PTS Rule. Over the last several years, the Heavy Section Steel Technology (HSST) Program at the Oak Ridge National Laboratory (ORNL) has performed a series of large-scale fracture-mechanics experiments. The Thermal Shock Experiments (TSE), Pressurized Thermal Shock Experiments (PTSE), and Wide Plate Experiments (WPE) produced K IC and K Ia data that suggest increased mean K IC and K Ia curves relative to the ones used in the IPTS study. Also, the PTSE and WPE have demonstrated that prototypical nuclear reactor pressure vessel steels are capable of arresting a propagating crack at K I values considerably above 220 MPa√m, the implicit limit of the ASME Code and the limit used in the IPTS studies. This document provides a discussion of the results of these experiments

  19. Performance of low-upper-shelf material under pressurized-thermal-shock loading (PTSE-2)

    International Nuclear Information System (INIS)

    Bryan, R.H.; Corwin, W.R.; Bass, B.R.; Nanstad, R.K.; Bolt, S.E.; Merkle, J.G.; Bryson, J.W.; Robinson, G.C.

    1988-01-01

    The second pressurized-thermal-shock experiment (Pse-2) of the Heavy-Section Steel Technology Program was conceived to investigate fracture behavior of steel with low ductile-tearing resistance. The experiment was performed in the pressurized-thermal-shock test facility at the Oak Ridge National Laboratory. PTSE-2 was designed primarily to reveal the interaction of ductile and brittle modes of fracture and secondarily to investigate the effects of warm pre-stressing. A test vessel was prepared by inserting a crack-like flaw of well-defined geometry on the outside surface of the vessel. The flaw was 1 m long by ∼ 15 mm deep. The instrumented vessel was placed in the test facility in which it ws initially heated to a uniform temperature and was then concurrently cooled on the outside and pressurized on the inside. These actions produced an evolution of temperature, toughness, and stress gradients relative to the prepared flaw that was appropriate to the planned objectives. The experiment was conducted in two separate transients, each one starting with the vessel nearly isothermal. The first transient induced a warm-prestressed state, during which K I first exceeded K Ic . This was followed by re-pressurization until a cleavage fracture propagated and arrested. The final transient was designed to produce and investigate a cleavage crack propagation followed by unstable tearing. During this transient, the fracture events occurred as had been planned. (author)

  20. The effect of hydrostatic vs. shock pressure treatment of plant seeds

    International Nuclear Information System (INIS)

    Mustey, A; Leighs, J A; Appleby, G J; Wood, D C; Hazael, R; McMillan, P F; Hazell, P J

    2014-01-01

    The hydrostatic pressure and shock response of plant seeds has been investigated antecedently, primarily driven by interest in reducing bacterial contamination of crops and the theory of panspermia, respectively. However, comparisons have not previously been made between these two methods ofapplying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in collected data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder setup and shock compression via employment of a 50 mm bore, single stage gas gun using the flyer plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set. Data collected has shown that cress seeds are extremely resilient to static loading, whereas the difference in the two forms of loading is negligible for lettuce seeds. Germination time has been seen to extend dramatically following static loading of cress seeds to greater than 0.4 GPa. In addition, the cut-off pressure previously seen to cause 0% germination in dynamic experiments performed on cress seeds has now also been seen in lettuce seeds.

  1. The effect of hydrostatic vs. shock pressure treatment of plant seeds

    Science.gov (United States)

    Mustey, A.; Leighs, J. A.; Appleby-Thomas, G. J.; Wood, D. C.; Hazael, R.; McMillan, P. F.; Hazell, P. J.

    2014-05-01

    The hydrostatic pressure and shock response of plant seeds has been investigated antecedently, primarily driven by interest in reducing bacterial contamination of crops and the theory of panspermia, respectively. However, comparisons have not previously been made between these two methods ofapplying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in collected data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder setup and shock compression via employment of a 50 mm bore, single stage gas gun using the flyer plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set. Data collected has shown that cress seeds are extremely resilient to static loading, whereas the difference in the two forms of loading is negligible for lettuce seeds. Germination time has been seen to extend dramatically following static loading of cress seeds to greater than 0.4 GPa. In addition, the cut-off pressure previously seen to cause 0% germination in dynamic experiments performed on cress seeds has now also been seen in lettuce seeds.

  2. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-Ray Preheat

    International Nuclear Information System (INIS)

    Colvin, Jeffrey D.; Kalantar, Daniel H.

    2006-01-01

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<1013 W/cm2, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flash-coating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

  3. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat

    International Nuclear Information System (INIS)

    Colvin, J D; Kalantar, D H

    2005-01-01

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, 13 W/cm 2 , compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

  4. Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

    Science.gov (United States)

    Murr, L. E.; Niou, C. S.; Pradhan-Advani, M.

    1991-01-01

    While it is now well established that copper-oxide-based power, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local

  5. Probabilistic approach to the analysis of reactor pressure vessel integrity during a pressurized thermal shock

    International Nuclear Information System (INIS)

    Adamec, P.

    2000-12-01

    Following a general summary of the issue, an overview of international experience (USA; Belgium, France, Germany, Russia, Spain, Sweden, The Netherlands, and the UK; and probabilistic PTS assessment for the reactor pressure vessel at Loviisa-1, Finland) is presented, and the applicable computer codes (VISA-II, OCA-P, FAVOR, ZERBERUS) are highlighted and their applicability to VVER type reactor pressure vessels is outlined. (P.A.)

  6. Pressure resistance of cold-shocked Escherichia coli O157:H7 in ground beef, beef gravy and peptone water.

    Science.gov (United States)

    Baccus-Taylor, G S H; Falloon, O C; Henry, N

    2015-06-01

    (i) To study the effects of cold shock on Escherichia coli O157:H7 cells. (ii) To determine if cold-shocked E. coli O157:H7 cells at stationary and exponential phases are more pressure-resistant than their non-cold-shocked counterparts. (iii) To investigate the baro-protective role of growth media (0·1% peptone water, beef gravy and ground beef). Quantitative estimates of lethality and sublethal injury were made using the differential plating method. There were no significant differences (P > 0·05) in the number of cells killed; cold-shocked or non-cold-shocked. Cells grown in ground beef (stationary and exponential phases) experienced lowest death compared with peptone water and beef gravy. Cold-shock treatment increased the sublethal injury to cells cultured in peptone water (stationary and exponential phases) and ground beef (exponential phase), but decreased the sublethal injury to cells in beef gravy (stationary phase). Cold shock did not confer greater resistance to stationary or exponential phase cells pressurized in peptone water, beef gravy or ground beef. Ground beef had the greatest baro-protective effect. Real food systems should be used in establishing food safety parameters for high-pressure treatments; micro-organisms are less resistant in model food systems, the use of which may underestimate the organisms' resistance. © 2015 The Society for Applied Microbiology.

  7. Wide range scaling laws for radiation driven shock speed, wall albedo and ablation parameters for high-Z materials

    Science.gov (United States)

    Mishra, Gaurav; Ghosh, Karabi; Ray, Aditi; Gupta, N. K.

    2018-06-01

    Radiation hydrodynamic (RHD) simulations for four different potential high-Z hohlraum materials, namely Tungsten (W), Gold (Au), Lead (Pb), and Uranium (U) are performed in order to investigate their performance with respect to x-ray absorption, re-emission and ablation properties, when irradiated by constant temperature drives. A universal functional form is derived for estimating time dependent wall albedo for high-Z materials. Among the high-Z materials studied, it is observed that for a fixed simulation time the albedo is maximum for Au below 250 eV, whereas it is maximum for U above 250 eV. New scaling laws for shock speed vs drive temperature, applicable over a wide temperature range of 100 eV to 500 eV, are proposed based on the physics of x-ray driven stationary ablation. The resulting scaling relation for a reference material Aluminium (Al), shows good agreement with that of Kauffman's power law for temperatures ranging from 100 eV to 275 eV. New scaling relations are also obtained for temperature dependent mass ablation rate and ablation pressure, through RHD simulation. Finally, our study reveals that for temperatures above 250 eV, U serves as a better hohlraum material since it offers maximum re-emission for x-rays along with comparable mass ablation rate. Nevertheless, traditional choice, Au works well for temperatures below 250 eV. Besides inertial confinement fusion (ICF), the new scaling relations may find its application in view-factor codes, which generally ignore atomic physics calculations of opacities and emissivities, details of laser-plasma interaction and hydrodynamic motions.

  8. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. The applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous`s empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing. 6 refs., 8 figs. (Author)

  9. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    International Nuclear Information System (INIS)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung

    1998-01-01

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. the applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous's empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing

  10. Nanocomposite-Based Microstructured Piezoresistive Pressure Sensors for Low-Pressure Measurement Range

    Directory of Open Access Journals (Sweden)

    Vasileios Mitrakos

    2018-01-01

    Full Text Available Piezoresistive pressure sensors capable of detecting ranges of low compressive stresses have been successfully fabricated and characterised. The 5.5 × 5 × 1.6 mm3 sensors consist of a planar aluminium top electrode and a microstructured bottom electrode containing a two-by-two array of truncated pyramids with a piezoresistive composite layer sandwiched in-between. The responses of two different piezocomposite materials, a Multiwalled Carbon Nanotube (MWCNT-elastomer composite and a Quantum Tunneling Composite (QTC, have been characterised as a function of applied pressure and effective contact area. The MWCNT piezoresistive composite-based sensor was able to detect pressures as low as 200 kPa. The QTC-based sensor was capable of detecting pressures as low as 50 kPa depending on the contact area of the bottom electrode. Such sensors could find useful applications requiring the detection of small compressive loads such as those encountered in haptic sensing or robotics.

  11. Fracture mechanics analysis of reactor pressure vessel under pressurized thermal shock - The effect of elastic-plastic behavior and stainless steel cladding -

    International Nuclear Information System (INIS)

    Joo, Jae Hwang; Kang, Ki Ju; Jhung, Myung Jo

    2002-01-01

    Performed here is an assessment study for deterministic fracture mechanics analysis of a pressurized thermal shock (PTS). The PTS event means an event or transient in pressurized water reactors (PWRs) causing severe overcooling (thermal shock) concurrent with or followed by significant pressure in the reactor vessel. The problems consisting of two transients and 10 cracks are solved and maximum stress intensity factors and maximum allowable nil-ductility reference temperatures are calculated. Their results are compared each other to address the general characteristics between transients, crack types and analysis methods. The effects of elastic-plastic material behavior and clad coating on the inner surface are explored

  12. Stress intensity factors for underclad and through clad defects in a reactor pressure vessel submitted to a pressurised thermal shock

    International Nuclear Information System (INIS)

    Marie, S.; Menager, Y.; Chapuliot, S.

    2005-01-01

    CEA has launched important work on the development of a Stress Intensity Factors compendium for cracks in a Reactor Pressure Vessel (RPV) taking into account the cladding. The work is performed by Finite Element analysis with a parametric mesh for two types of defects (under clad defect and through clad defect) and a wide range of geometrical and material parameters. In addition, an analytical stress solution for Pressurised Thermal Shock (PTS) on the RPV is proposed to allow a complete analytical estimation of the stress intensity factor K I for the PTS problem. The results are validated by comparison with a complete 3D finite element calculation performed on a complex and realistic case study

  13. Analysis of Reactor Pressurized Thermal Shock Conditions Considering Upgrading of Systems Important to Safety

    International Nuclear Information System (INIS)

    Mazurok, A.S; Vyshemirskyij, M.P.

    2015-01-01

    The paper analyzes conditions of pressurized thermal shock on the reactor pressure vessel taking into account upgrading of the emergency core cooling system and primary overpressure protection system. For representative accident scenarios, calculation and comparative analysis was carried out. These scenarios include a small leak from the hot leg and PRZ SV stuck opening with re closure after 3600 sec and 3 SG heat transfer tube rupture. The efficiency of mass flow control by valves on the pump head (emergency core cooling systems) and cold overpressure protection (primary overpressure protection system) was analyzed. The thermal hydraulic model for RELAP5/Mod3.2 code with detailed downcomer (DC) model and changes in accordance with upgrades was used for calculations. Detailed (realistic) modeling of piping and equipment was performed. The upgrades prevent excessive primary cooling and, consequently, help to preserve the RPV integrity and to avoid the formation of a through crack, which can lead to a severe accident

  14. Pressurized thermal shock evaluation of the Calvert Cliffs Unit 1 Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, L [ed.

    1985-09-01

    An evaluation of the risk to the Calvert Cliffs Unit 1 nuclear power plant due to pressurized thermal shock (PTS) has been completed by Oak Ridge National Laboratory (ORNL) with the assistance of several other organizations. This evaluation was part of a Nuclear Regulatory Commission program designed to study the PTS risk to three nuclear plants, the other two plants being Oconee Unit 1 and H.B. Robinson Unit 2. The specific objectives of the program were to (1) provide a best estimate of the frequency of a through-the-wall crack in the pressure vessel at each of the three plants, together with the uncertainty in the estimated frequency and its sensitivity to the variables used in the evaluation; (2) determine the dominant overcooling sequences contributing to the estimated frequency and the associated failures in the plant systems or in operator actions; and (3) evaluate the effectiveness of potential corrective measures.

  15. RETRAN applications in pressurized thermal shock analysis of turkey point units 3 and 4

    International Nuclear Information System (INIS)

    Arpa, J.; Fatemi, A.S.; Mathavan, S.K.

    1985-01-01

    A methodology to assess the impact of overcooling transients on vessel wall integrity with respect to pressurized thermal shock conditions has been developed at Florida Power and Light Company for the Turkey Point Nuclear Units. Small break loss-of-coolant and small steamline break events have been simulated with the RETRAN code. Highly conservative assumptions, such as engineered safeguards with minimum temperature and maximum flow, have been made to maximize cooldown and thermal stress in the vessel wall. Temperatures, pressures, and flows obtained with RETRAN provide input for stress and fracture mechanics analyses that evaluate reactor vessel integrity. The results of the RETRAN analyses compare well with generic calculations performed by the Westinghouse Owners Group for a similar type of plant

  16. Pressurized thermal shock evaluation of the Calvert Cliffs Unit 1 Nuclear Power Plant

    International Nuclear Information System (INIS)

    Abbott, L.

    1985-09-01

    An evaluation of the risk to the Calvert Cliffs Unit 1 nuclear power plant due to pressurized thermal shock (PTS) has been completed by Oak Ridge National Laboratory (ORNL) with the assistance of several other organizations. This evaluation was part of a Nuclear Regulatory Commission program designed to study the PTS risk to three nuclear plants, the other two plants being Oconee Unit 1 and H.B. Robinson Unit 2. The specific objectives of the program were to (1) provide a best estimate of the frequency of a through-the-wall crack in the pressure vessel at each of the three plants, together with the uncertainty in the estimated frequency and its sensitivity to the variables used in the evaluation; (2) determine the dominant overcooling sequences contributing to the estimated frequency and the associated failures in the plant systems or in operator actions; and (3) evaluate the effectiveness of potential corrective measures

  17. Computational methods for fracture mechanics analysis of pressurized-thermal-shock experiments

    International Nuclear Information System (INIS)

    Bass, B.R.; Bryan, R.H.; Bryson, J.W.; Merkle, J.G.

    1984-01-01

    Extensive computational analyses are required to determine material parameters and optimum pressure-temperature transients compatible with proposed pressurized-thermal-shock (PTS) test scenarios and with the capabilities of the PTS test facility at the Oak Ridge National Laboratory (ORNL). Computational economy has led to the application of techniques suitable for parametric studies involving the analysis of a large number of transients. These techniques, which include analysis capability for two- and three-dimensional (2-D and 3-D) superposition, inelastic ligament stability, and upper-shelf arrest, have been incorporated into the OCA/USA computer program. Features of the OCA/USA program are discussed, including applications to the PTS test configuration

  18. Computational methods for fracture mechanics analysis of pressurized-thermal-shock experiments

    International Nuclear Information System (INIS)

    Bass, B.R.; Bryan, R.H.; Bryson, J.W.; Merkle, J.G.

    1984-01-01

    Extensive computational analyses are required to determine material parameters and optimum pressure-temperature transients compatible with proposed pressurized-thermal-shock (PTS) test scenarios and with the capabilities of the PTS test facility at the Oak Ridge National Laboratory (ORNL). Computational economy has led to the application of techniques suitable for parametric studies involving the analysis of a large number of transients. These techniques, which include analysis capability for two- and three-dimensional (2-D and 3-D) superposition, inelastic ligament stability, and upper-shelf arrest, have been incorporated into the OCA/ USA computer program. Features of the OCA/USA program are discussed, including applications to the PTS test configuration. (author)

  19. Temperature measurement in the liquid helium range at pressure

    International Nuclear Information System (INIS)

    Itskevich, E.S.; Krajdenov, V.F.

    1978-01-01

    The use of bronze and germanium resistance thermometers and the use of a (Au + 0.07 % Fe)-Cu thermocouple for temperature measurements from 1.5 to 4.2 K in the hydrostatic compression of up to 10 kbar are considered. To this aim, the thermometer resistance as a function of temperature and pressure is measured. It is revealed that pressure does not change the thermometric response of the bronze resistance thermometer but only shifts it to the region of lower temperatures. The identical investigations of the germanium resistance thermometer shows that strong temperature dependence and the shift of its thermometric response under the influence of pressure make the use of germanium resistance thermometers in high-pressure chambers very inconvenient. The results of the analysis of the (Au + 0.07 % Fe) - Cu thermocouple shows that with a 2 per cent accuracy the thermocouple Seebeck coefficient does not depend on pressure. It permits to use this thermocouple for temperature measurements at high pressures

  20. Ductile fracture prediction of an axially cracked pressure vessel under pressurized thermal shock

    International Nuclear Information System (INIS)

    Takahashi, Jun; Okamura, Hiroyuki

    1991-01-01

    In this paper, the J-value of an axially cracked cylinder under several PTS conditions are evaluated using a simple estimation scheme which we proposed. Results obtained are summerized as follow: (1) Under any PTS conditions, the effect of internal pressure is so predominant upon the J-value and dJ/da that it is very important to grasp the transient of internal pressure under any imaginable accident from the viewpoint of structural integrity. (2) Under any IP, TS, and PTS conditions, J - a/W relation shows that the J-value reaches its maximum at a certain crack depth, then drops to zero at a/W ≅ 0.9. Though the effect of inertia is not taken into account, this fact may explain the phenomena of crack arrest qualitatively. (3) The compliance of a cylindrical shell plays an important role in the fracture prediction of a pressure vessel. (4) Under typical PTS conditions, the region at the crack tip dominated by the Hutchinson-Rice-Rosengren singularity is substantially large enough to apply the J-based criterion to predict unstable ductile fracture. (author)

  1. Shock experiments in range of 10–45 GPa with small multidomain magnetite in porous targets

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Pesonen, L. J.; Deutsch, A.; Wünnemann, K.; Nowka, D.; Hornemann, U.; Heikinheimo, E.

    2012-01-01

    Roč. 47, č. 10 (2012), s. 1671-1680 ISSN 1086-9379 Institutional research plan: CEZ:AV0Z30130516 Keywords : shock * magnetite * magnetism * magnetic properties * density porosity Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.800, year: 2012

  2. Effect of Pressure Gradients on the Initiation of PBX-9502 via Irregular (Mach) Reflection of Low Pressure Curved Shock Waves

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Lawrence Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Miller, Phillip Isaac [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moro, Erik Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-28

    In the instance of multiple fragment impact on cased explosive, isolated curved shocks are generated in the explosive. These curved shocks propagate and may interact and form irregular or Mach reflections along the interaction loci, thereby producing a single shock that may be sufficient to initiate PBX-9501. However, the incident shocks are divergent and their intensity generally decreases as they expand, and the regions behind the Mach stem interaction loci are generally unsupported and allow release waves to rapidly affect the flow. The effects of release waves and divergent shocks may be considered theoretically through a “Shock Change Equation”.

  3. Inline pressure sensing mechanisms enabling scalable range and sensitivity

    NARCIS (Netherlands)

    Alveringh, Dennis; Groenesteijn, Jarno; Wiegerink, Remco J.; Lötters, Joost Conrad

    2015-01-01

    We report on two novel capacitive pressure sensing mechanisms that allow measurements inline with other fluidic devices on one chip, without introducing a large internal volume to the fluid path. The first sensing mechanism is based on out-of-plane bending of a U-shaped channel and the same

  4. Documentation of probabilistic fracture mechanics codes used for reactor pressure vessels subjected to pressurized thermal shock loading: Parts 1 and 2. Final report

    International Nuclear Information System (INIS)

    Balkey, K.; Witt, F.J.; Bishop, B.A.

    1995-06-01

    Significant attention has been focused on the issue of reactor vessel pressurized thermal shock (PTS) for many years. Pressurized thermal shock transient events are characterized by a rapid cooldown at potentially high pressure levels that could lead to a reactor vessel integrity concern for some pressurized water reactors. As a result of regulatory and industry efforts in the early 1980's, a probabilistic risk assessment methodology has been established to address this concern. Probabilistic fracture mechanics analyses are performed as part of this methodology to determine conditional probability of significant flaw extension for given pressurized thermal shock events. While recent industry efforts are underway to benchmark probabilistic fracture mechanics computer codes that are currently used by the nuclear industry, Part I of this report describes the comparison of two independent computer codes used at the time of the development of the original U.S. Nuclear Regulatory Commission (NRC) pressurized thermal shock rule. The work that was originally performed in 1982 and 1983 to compare the U.S. NRC - VISA and Westinghouse (W) - PFM computer codes has been documented and is provided in Part I of this report. Part II of this report describes the results of more recent industry efforts to benchmark PFM computer codes used by the nuclear industry. This study was conducted as part of the USNRC-EPRI Coordinated Research Program for reviewing the technical basis for pressurized thermal shock (PTS) analyses of the reactor pressure vessel. The work focused on the probabilistic fracture mechanics (PFM) analysis codes and methods used to perform the PTS calculations. An in-depth review of the methodologies was performed to verify the accuracy and adequacy of the various different codes. The review was structured around a series of benchmark sample problems to provide a specific context for discussion and examination of the fracture mechanics methodology

  5. Probabilistic fracture mechanics analysis of reactor vessel for pressurized thermal shock: the effect of residual stress and fracture toughness

    International Nuclear Information System (INIS)

    Jung, Sung Gyu; Jin, Tae Eun; Jhung, Myung Jo; Choi, Young Hwan

    2003-01-01

    The structural integrity of the reactor vessel with the approaching end of life must be assured for pressurized thermal shock. The regulation specifies the screening criteria for this and requires that specific analysis be performed for the reactor vessel which is anticipated to exceed the screening criteria at the end of plant life. In case the screening criteria is exceeded by the deterministic analysis, probabilistic analysis must be performed to show that failure probability is within the limit. In this study, probabilistic fracture mechanics analysis of the reactor vessel for pressurized thermal shock is performed and the effects of residual stress and master curve on the failure probability are investigated

  6. Shock Tube and Ballistic Range Facilities at NASA Ames Research Center

    Science.gov (United States)

    Grinstead, Jay H.; Wilder, Michael C.; Reda, Daniel C.; Cornelison, Charles J.; Cruden, Brett A.; Bogdanoff, David W.

    2010-01-01

    The Electric Arc Shock Tube (EAST) facility and the Hypervelocity Free Flight Aerodynamic Facility (HFFAF) at NASA Ames Research Center are described. These facilities have been in operation since the 1960s and have supported many NASA missions and technology development initiatives. The facilities have world-unique capabilities that enable experimental studies of real-gas aerothermal, gas dynamic, and kinetic phenomena of atmospheric entry.

  7. Effects of low upper shelf fracture toughness on reactor vessel integrity during pressurized thermal shock events

    International Nuclear Information System (INIS)

    Bamford, W.H.; Heinecke, C.C.; Balkey, K.R.

    1988-01-01

    For the past decade, significant attention has been focused on the subject of nuclear rector vessel integrity during pressurized thermal shock (PTS) events. The issue of low upper shelf fracture toughness at operating temperatures has been a consideration for some reactor vessel materials since the early 1970's. Deterministic and probabilistic fracture mechanics sensitivity studies have been completed to evaluate the interaction between the PTS and lower upper shelf toughness issues that result from neutron embrittlement of the critical beltline region materials. This paper presents the results of these studies to show the interdependency of these fracture considerations in certain instances and to identify parameters that need to be carefully treated in reactor vessel integrity evaluations for these subjects. This issue is of great importance to those vessels which have low upper shelf toughness, both for demonstrating safety during the original design life and in life extension assessments

  8. Analysis of crack behavior in the JRC Ispra pressurized thermal shock experiment

    International Nuclear Information System (INIS)

    Jovanovic, A.; Lucia, A.C.

    1990-01-01

    The analytical work performed in the framework of the Pressurized Thermal Shock (PTS) experimental research at the JRC Ispra, Italy, is described in the paper. In particular, the development of the FRAP preprocessor and development and implementation of a methodology for analysis of local non-stationary heat transfer coefficients during a PTS, have been tackled. FRAP is used as a front-end for the finite element code ABAQUS, for the heat transfer, stress and fracture mechanics analyses. The ABAQUS results are used further on, for the probabilistic fatigue crack analysis performed by the JRC Ispra code COVASTOL. Only the preliminary results of application of FRAP, ABAQUS and COVASTOL codes in the experiment are given in this paper, in order to illustrate the applied analytical procedure. (orig.)

  9. A quantitative methodology for reactor vessel pressurized thermal shock decision making

    International Nuclear Information System (INIS)

    Ackerson, D.S.; Balkey, K.R.; Meyer, T.A.; Ofstun, R.P.; Rupprecht, S.D.; Sharp, D.R.

    1983-01-01

    The recent operating experience of the Pressurized Water Reactor (PWR) Industry has focused increasing attention on the issue of reactor vessel pressurized thermal shock (PTS). Previous reactor vessel integrity concerns have led to changes in vessel and plant system design and to operating procedures, and increased attention to the PTS issue is causing consideration of further modifications. Events such as excess feedwater, loss of normal feedwater, and steam generator tube rupture have led to significant primary system cooldowns. Each of these cooldown transients occurred concurrently with a relatively high primary system pressure. Considerations of these and other postulated cooldown events has drawn attention to the impact of operator action and control system effects on reactor vessel PTS. A methodology, which couples event sequence analysis with probabilistic fracture mechanics analyses, was developed to identify those events that are of primary concern for reactor vessel integrity. Operating experience is utilized to aid in defining the appropriate event sequences and event frequencies of occurrence for the evaluation. (orig./RW)

  10. IPTS [Integrated Pressurized-Thermal-Shock] study for H.B. Robinson (HBR-HYPO)

    International Nuclear Information System (INIS)

    Cheverton, R.D.

    1990-01-01

    A primary purpose of the US Nuclear Regulatory Commission (NRC) Integrated Pressurized-Thermal-Shock (IPTS) Program, completed in 1985, was to develop an integrated probabilistic approach for evaluating pressurized water reactor (PWR) pressure vessel integrity; and the scope included the application of the methodology to three ''high risk'' PWR plants. The three plants selected were Oconee Unit 1, Calvert Cliffs Unit 1, and HBRobinson Unit 2 (HBR-2); and the plant studies were conducted in that order. As a result of this sequence and the developmental nature of the program, the HBR-2 study was the more complete and state-of-the-art. However, by the time the HBR-2 study was conducted, a reevaluation of vessel chemistry and reference nil-ductility transition temperature (RT NDT ) had indicated relatively low concentrations of copper and nickel and low values of initial RT NDT (RT NDT 0 ), resulting in very low probabilities of failure. Thus, for illustrative purposes, copper, nickel, and RT NDT 0 were increased so that RT NDT (2σ) = 270 degree F for the critical weld at 32 EFPY. This value of RT NDT corresponds, of course, to the NRC PTS-Rule screening criteria (10 CFR 5.61). This hypothetical ''plant'' was referred to as HBR-HYPO, and it was identical to HBR-2 in every respect except for the concentrations of copper and nickel and the value of RT NDT 0 for the welds. 3 refs

  11. Preliminary applications of the new Neptune two-phase CFD solver to pressurized thermal shock investigations

    International Nuclear Information System (INIS)

    Boucker, M.; Laviaville, J.; Martin, A.; Bechaud, C.; Bestion, D.; Coste, P.

    2004-01-01

    The objective of this communication is to present some preliminary applications to pressurized thermal shock (PTS) investigations of the CFD (Computational Fluid Dynamics) two-phase flow solver of the new NEPTUNE thermal-hydraulics platform. In the framework of plant life extension, the Reactor Pressure Vessel (RPV) integrity is a major concern, and an important part of RPV integrity assessment is related to PTS analysis. In the case where the cold legs are partially filled with steam, it becomes a two-phase problem and new important effects occur, such as condensation due to the Emergency Core Cooling (ECC) injections of sub-cooled water. Thus, an advanced prediction of RPV thermal loading during these transients requires sophisticated two-phase, local scale, 3-dimensional codes. In that purpose, a program has been set up to extend the capabilities of the NEPTUNE two-phase CFD solver. A simple set of turbulence and condensation model for free surface steam-water flow has been tested in simulation of an ECC high pressure injection representing facility, using a full 3-dimensional mesh and the new NEPTUNE solver. Encouraging results have been obtained but it should be noticed that several sources of error can compensate for one another. Nevertheless, the computation presented here allows to be reasonable confident in the use of two-phase CFD in order to carry out refined analysis of two-phase PTS scenarios within the next years

  12. Pressurized thermal shock in nuclear power plants: Good practices for assessment. Deterministic evaluation for the integrity of reactor pressure vessel

    International Nuclear Information System (INIS)

    2010-02-01

    Starting in the early 1970s, a series of coordinated research projects (CRPs) was sponsored by the IAEA focusing on the effects of neutron radiation on reactor pressure vessel (RPV) steels and RPV integrity. In conjunction with these CRPs, many consultants meetings, specialists meetings, and international conferences, dating back to the mid-1960s, were held. Individual studies on the basic phenomena of radiation hardening and embrittlement were also performed to better understand increases in tensile strength and shifts to higher temperatures for the integrity of the RPV. The overall objective of this CRP was to perform benchmark deterministic calculations of a typical pressurized thermal shock (PTS) regime, with the aim of comparing the effects of individual parameters on the final RPV integrity assessment, and then to recommend the best practices for their implementation in PTS procedures. At present, several different procedures and approaches are used for RPV integrity assessment for both WWER 440-230 reactors and pressurized water reactors (PWRs). These differences in procedures and approaches are based, in principle, on the different codes and rules used for design and manufacturing, and the different materials used for the various types of reactor, and the different levels of implementation of recent developments in fracture mechanics. Benchmark calculations were performed to improve user qualification and to reduce the user effect on the results of the analysis. This addressed generic PWR and WWER types of RPV, as well as sensitivity analyses. The complementary sensitivity analyses showed that the following factors significantly influenced the assessment: flaw size, shape, location and orientation, thermal hydraulic assumptions and material toughness. Applying national codes and procedures to the benchmark cases produced significantly different results in terms of allowable material toughness. This was mainly related to the safety factors used and the

  13. Fracture-mechanics data deduced from thermal-shock and related experiments with LWR pressure-vessel material

    International Nuclear Information System (INIS)

    Cheverton, R.D.; Canonico, D.A.; Iskander, S.K.; Bolt, S.E.; Holz, P.P.; Nanstad, R.K.; Stelzman, W.J.

    1982-01-01

    Pressurized water reactors (PWRs) are susceptible to certain types of hypothetical accidents that can subject the reactor pressure vessel to severe thermal shock, that is, a rapid cooling of the inner surface of the vessel wall. The thermal-shock loading, coupled with the radiation-induced reduction in the material fracture toughness, introduces the possibility of propagation of preexistent flaws and what at one time were regarded as somewhat unique fracture-oriented conditions. Several postulated reactor accidents have been analyzed to discover flaw behavior trends; seven intermediate-scale thermal-shock experiments with steel cylinders have been conducted; and corresponding materials characterization studies have been performed. Flaw behavior trends and related fracture-mechanics data deduced from these studies are discussed

  14. Application of the French codes to the pressurized thermal shocks assessment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingya; Wang, Rong Shan; Yu, Weiwei; Lu, Feng; Zhang, Guo Dong; Xue, Fei; Chen, Zhilin [Suzhou Nuclear Power Research Institute, Life Management Center, Suzhou (China); Qian, Guian [Paul Scherrer Institute, Nuclear Energy and Safety Department, Villigen (Switzerland); Shi, Jinhua [Amec Foster Wheeler, Clean Energy Department, Gloucester (United Kingdom)

    2016-12-15

    The integrity of a reactor pressure vessel (RPV) related to pressurized thermal shocks (PTSs) has been extensively studied. This paper introduces an integrity assessment of an RPV subjected to a PTS transient based on the French codes. In the USA, the 'screening criterion' for maximum allowable embrittlement of RPV material is developed based on the probabilistic fracture mechanics. However, in the French RCC-M and RSE-M codes, which are developed based on the deterministic fracture mechanics, there is no 'screening criterion'. In this paper, the methodology in the RCC-M and RSE-M codes, which are used for PTS analysis, are firstly discussed. The bases of the French codes are compared with ASME and FAVOR codes. A case study is also presented. The results show that the method in the RCC-M code that accounts for the influence of cladding on the stress intensity factor (SIF) may be nonconservative. The SIF almost doubles if the weld residual stress is considered. The approaches included in the codes differ in many aspects, which may result in significant differences in the assessment results. Therefore, homogenization of the codes in the long time operation of nuclear power plants is needed.

  15. Pressurized thermal shocks: the JRC Ispra experimental test rig and analytical results

    International Nuclear Information System (INIS)

    Jovanovic, A.; Lucia, A.C.

    1990-01-01

    The paper tackles some issues of particular interest for the remanent (remaining) life prediction for the pressurized components exposed to pressurized thermal shock (PTS) loads, that have been tackled in analytical work performed in the framework of the MPA - JRC collaboration for the PTS experimental research at the JRC Ispra. These issues regard in general application of damage mechanics, fracture mechanics and artificial intelligence (including the treatment of uncertainties in the PTS analysis and experiments). The considered issues are essential for further understanding and modelling of the crack behaviour and of the component response in PTS conditions. In particular, the development of the FRAP preprocessor and development and implementation of a methodology for analysis of local non-stationary heat transfer coefficients during a PTS, have been explained more in detail. FRAP is used as a frontend, for the finite element code ABAQUS, for the heat transfer, stress and fracture mechanics analyses. The ABAQUS results are used further on, for the probabilistic fatigue crack growth analysis performed by the COVASTOL code. (author)

  16. Application of the French Codes to the Pressurized Thermal Shocks Assessment

    Directory of Open Access Journals (Sweden)

    Mingya Chen

    2016-12-01

    Full Text Available The integrity of a reactor pressure vessel (RPV related to pressurized thermal shocks (PTSs has been extensively studied. This paper introduces an integrity assessment of an RPV subjected to a PTS transient based on the French codes. In the USA, the “screening criterion” for maximum allowable embrittlement of RPV material is developed based on the probabilistic fracture mechanics. However, in the French RCC-M and RSE-M codes, which are developed based on the deterministic fracture mechanics, there is no “screening criterion”. In this paper, the methodology in the RCC-M and RSE-M codes, which are used for PTS analysis, are firstly discussed. The bases of the French codes are compared with ASME and FAVOR codes. A case study is also presented. The results show that the method in the RCC-M code that accounts for the influence of cladding on the stress intensity factor (SIF may be nonconservative. The SIF almost doubles if the weld residual stress is considered. The approaches included in the codes differ in many aspects, which may result in significant differences in the assessment results. Therefore, homogenization of the codes in the long time operation of nuclear power plants is needed.

  17. Application of the French codes to the pressurized thermal shocks assessment

    International Nuclear Information System (INIS)

    Chen, Mingya; Wang, Rong Shan; Yu, Weiwei; Lu, Feng; Zhang, Guo Dong; Xue, Fei; Chen, Zhilin; Qian, Guian; Shi, Jinhua

    2016-01-01

    The integrity of a reactor pressure vessel (RPV) related to pressurized thermal shocks (PTSs) has been extensively studied. This paper introduces an integrity assessment of an RPV subjected to a PTS transient based on the French codes. In the USA, the 'screening criterion' for maximum allowable embrittlement of RPV material is developed based on the probabilistic fracture mechanics. However, in the French RCC-M and RSE-M codes, which are developed based on the deterministic fracture mechanics, there is no 'screening criterion'. In this paper, the methodology in the RCC-M and RSE-M codes, which are used for PTS analysis, are firstly discussed. The bases of the French codes are compared with ASME and FAVOR codes. A case study is also presented. The results show that the method in the RCC-M code that accounts for the influence of cladding on the stress intensity factor (SIF) may be nonconservative. The SIF almost doubles if the weld residual stress is considered. The approaches included in the codes differ in many aspects, which may result in significant differences in the assessment results. Therefore, homogenization of the codes in the long time operation of nuclear power plants is needed

  18. Elastic precursor wave decay in shock-compressed aluminum over a wide range of temperature

    Science.gov (United States)

    Austin, Ryan A.

    2018-01-01

    The effect of temperature on the dynamic flow behavior of aluminum is considered in the context of precursor wave decay measurements and simulations. In this regard, a dislocation-based model of high-rate metal plasticity is brought into agreement with previous measurements of evolving wave profiles at 300 to 933 K, wherein the amplification of the precursor structure with temperature arises naturally from the dislocation mechanics treatment. The model suggests that the kinetics of inelastic flow and stress relaxation are governed primarily by phonon scattering and radiative damping (sound wave emission from dislocation cores), both of which intensify with temperature. The manifestation of these drag effects is linked to low dislocation density ahead of the precursor wave and the high mobility of dislocations in the face-centered cubic lattice. Simulations performed using other typical models of shock wave plasticity do not reproduce the observed temperature-dependence of elastic/plastic wave structure.

  19. Potential impact of enhanced fracture-toughness data on pressurized-thermal-shock analysis

    International Nuclear Information System (INIS)

    Dickson, T.L.; Theiss, T.J.

    1990-01-01

    The Heavy Section Steel Technology (HSST) Program is involved with the generation of ''enhanced'' fracture-initiation toughness and fracture-arrest toughness data of prototypic nuclear reactor vessel steels. These two sets of data are enhanced because they have distinguishing characteristics that could potentially impact PWR pressure vessel integrity assessments for the pressurized-thermal shock (PTS) loading condition which is a major plant-life extension issue to be confronted in the 1990's. Currently, the HSST Program is planning experiments to verify and quantify, for A533B steel, the distinguishing characteristic of elevated initiation-fracture toughness for shallow flaws which has been observed for other steels. Deterministic and probabilistic fracture-mechanics analyses were performed to examine the influence of the enhanced initiation and arrest fracture-toughness data on the cleavage fracture response of a nuclear reactor pressure vessel subjected to PTS loading. The results of the analyses indicated that application of the enhanced K Ia data does reduce the conditional probability of failure P(F|E); however, it does not appear to have the potential to significantly impact the results of PTS analyses. The application of enhanced fracture-initiation-toughness data for shallow flaws also reduces P(F|E), but it does appear to have a potential for significantly affecting the results of PTS analyses. The effect of including Type I warm prestress in probabilistic fracture-mechanics analyses is beneficial. The benefit is transient dependent and, in some cases, can be quite significant. 19 refs., 12 figs., 1 tab

  20. Verification, validation and application of NEPTUNE-CFD to two-phase Pressurized Thermal Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Mérigoux, N., E-mail: nicolas.merigoux@edf.fr [Electricité de France, R& D Division, 6 Quai Watier, 78401 Chatou (France); Laviéville, J.; Mimouni, S.; Guingo, M.; Baudry, C. [Electricité de France, R& D Division, 6 Quai Watier, 78401 Chatou (France); Bellet, S., E-mail: serge.bellet@edf.fr [Electricité de France, Thermal & Nuclear Studies and Projects Division, 12-14 Avenue Dutriévoz, 69628 Villeurbanne (France)

    2017-02-15

    Nuclear Power Plants are subjected to a variety of ageing mechanisms and, at the same time, exposed to potential Pressurized Thermal Shock (PTS) – characterized by a rapid cooling of the Reactor Pressure Vessel (RPV) wall. In this context, NEPTUNE-CFD is developed and used to model two-phase PTS in an industrial configuration, providing temperature and pressure fields required to assess the integrity of the RPV. Furthermore, when using CFD for nuclear safety demonstration purposes, EDF applies a methodology based on physical analysis, verification, validation and application to industrial scale (V&V), to demonstrate the quality of, and the confidence in results obtained. By following this methodology, each step must be proved to be consistent with the others, and with the final goal of the calculations. To this effect, a chart demonstrating how far the validation step of NEPTUNE-CFD is covering the PTS application will be drawn. A selection of the code verification and validation cases against different experiments will be described. For results consistency, a single and mature set of models – resulting from the knowledge acquired during the code development over the last decade – has been used. From these development and validation feedbacks, a methodology has been set up to perform industrial computations. Finally, the guidelines of this methodology based on NEPTUNE-CFD and SYRTHES coupling – to take into account the conjugate heat transfer between liquid and solid – will be presented. A short overview of the engineering approach will be given – starting from the meshing process, up to the results post-treatment and analysis.

  1. Reynolds stress turbulence model applied to two-phase pressurized thermal shocks in nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Mérigoux, Nicolas, E-mail: nicolas.merigoux@edf.fr; Laviéville, Jérôme; Mimouni, Stéphane; Guingo, Mathieu; Baudry, Cyril

    2016-04-01

    Highlights: • NEPTUNE-CFD is used to model two-phase PTS. • k-ε model did produce some satisfactory results but also highlights some weaknesses. • A more advanced turbulence model has been developed, validated and applied for PTS. • Coupled with LIM, the first results confirmed the increased accuracy of the approach. - Abstract: Nuclear power plants are subjected to a variety of ageing mechanisms and, at the same time, exposed to potential pressurized thermal shock (PTS) – characterized by a rapid cooling of the internal Reactor Pressure Vessel (RPV) surface. In this context, NEPTUNE-CFD is used to model two-phase PTS and give an assessment on the structural integrity of the RPV. The first available choice was to use standard first order turbulence model (k-ε) to model high-Reynolds number flows encountered in Pressurized Water Reactor (PWR) primary circuits. In a first attempt, the use of k-ε model did produce some satisfactory results in terms of condensation rate and temperature field distribution on integral experiments, but also highlights some weaknesses in the way to model highly anisotropic turbulence. One way to improve the turbulence prediction – and consequently the temperature field distribution – is to opt for more advanced Reynolds Stress turbulence Model. After various verification and validation steps on separated effects cases – co-current air/steam-water stratified flows in rectangular channels, water jet impingements on water pool free surfaces – this Reynolds Stress turbulence Model (R{sub ij}-ε SSG) has been applied for the first time to thermal free surface flows under industrial conditions on COSI and TOPFLOW-PTS experiments. Coupled with the Large Interface Model, the first results confirmed the adequacy and increased accuracy of the approach in an industrial context.

  2. High Resolution and Large Dynamic Range Resonant Pressure Sensor Based on Q-Factor Measurement

    Science.gov (United States)

    Gutierrez, Roman C. (Inventor); Stell, Christopher B. (Inventor); Tang, Tony K. (Inventor); Vorperian, Vatche (Inventor); Wilcox, Jaroslava (Inventor); Shcheglov, Kirill (Inventor); Kaiser, William J. (Inventor)

    2000-01-01

    A pressure sensor has a high degree of accuracy over a wide range of pressures. Using a pressure sensor relying upon resonant oscillations to determine pressure, a driving circuit drives such a pressure sensor at resonance and tracks resonant frequency and amplitude shifts with changes in pressure. Pressure changes affect the Q-factor of the resonating portion of the pressure sensor. Such Q-factor changes are detected by the driving/sensing circuit which in turn tracks the changes in resonant frequency to maintain the pressure sensor at resonance. Changes in the Q-factor are reflected in changes of amplitude of the resonating pressure sensor. In response, upon sensing the changes in the amplitude, the driving circuit changes the force or strength of the electrostatic driving signal to maintain the resonator at constant amplitude. The amplitude of the driving signals become a direct measure of the changes in pressure as the operating characteristics of the resonator give rise to a linear response curve for the amplitude of the driving signal. Pressure change resolution is on the order of 10(exp -6) torr over a range spanning from 7,600 torr to 10(exp -6) torr. No temperature compensation for the pressure sensor of the present invention is foreseen. Power requirements for the pressure sensor are generally minimal due to the low-loss mechanical design of the resonating pressure sensor and the simple control electronics.

  3. Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges.

    Science.gov (United States)

    Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

    2017-03-31

    Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.

  4. Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-1 and TSE-2

    International Nuclear Information System (INIS)

    Cheverton, R.D.

    1976-09-01

    The LOCA-ECC Thermal Shock Program was established to investigate the potential for flaw propagation in pressurized-water reactor (PWR) vessels during injection of emergency core coolant following a loss-of-coolant accident. Studies thus far have included fracture mechanics analyses of typical PWRs, the design and construction of a thermal shock test facility, determination of material properties for test specimens, and two thermal shock experiments with 0.53-m-OD (21-in.) by 0.15-m-wall (6-in.) cylindrical test specimens. The PWR calculations indicated that under some circumstances crack propagation could be expected and that experiments should be conducted for cracks that would have the potential for propagation at least halfway through the wall

  5. Measurement of high-pressure shock waves in cryogenic deuterium-tritium ice layered capsule implosions on NIF.

    Science.gov (United States)

    Robey, H F; Moody, J D; Celliers, P M; Ross, J S; Ralph, J; Le Pape, S; Berzak Hopkins, L; Parham, T; Sater, J; Mapoles, E R; Holunga, D M; Walters, C F; Haid, B J; Kozioziemski, B J; Dylla-Spears, R J; Krauter, K G; Frieders, G; Ross, G; Bowers, M W; Strozzi, D J; Yoxall, B E; Hamza, A V; Dzenitis, B; Bhandarkar, S D; Young, B; Van Wonterghem, B M; Atherton, L J; Landen, O L; Edwards, M J; Boehly, T R

    2013-08-09

    The first measurements of multiple, high-pressure shock waves in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility have been performed. The strength and relative timing of these shocks must be adjusted to very high precision in order to keep the DT fuel entropy low and compressibility high. All previous measurements of shock timing in inertial confinement fusion implosions [T. R. Boehly et al., Phys. Rev. Lett. 106, 195005 (2011), H. F. Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] have been performed in surrogate targets, where the solid DT ice shell and central DT gas regions were replaced with a continuous liquid deuterium (D2) fill. This report presents the first experimental validation of the assumptions underlying this surrogate technique.

  6. Back-pressure Effect on Shock-Train Location in a Scramjet Engine Isolator

    Science.gov (United States)

    2010-03-01

    breathing single-stage-to-orbit ( SSTO ) reusable spacecraft, X-30. It made a great contribution towards developing a rectangular, airframe-integrated...scramjet. This program was cancelled without conducting a flight test. The goal of this program was to build a full scale operational SSTO vehicle...bomber, SSTO , or hypersonic transportation. Shock system A shock-train is a system of series of oblique or normal shocks, which is a very complex flow

  7. Investigation of pressure transients in nuclear filtration systems: construction details of a large shock tube

    International Nuclear Information System (INIS)

    Smith, P.R.; Gregory, W.S.

    1980-04-01

    This report documents the construction of a 0.914-m (36-in.)-dia. shock tube on the New Mexico State University caompus. Highly variable low-grade explosions can be simulated with the shock tube. We plan to investigate the response of nuclear facility ventilation system components to low-grade explosions. Components of particular interest are high-capacity, high efficiency paticulate air (HEPA) filters. Shock tube construction details, operating principles, firing sequence, and preliminary results are reported

  8. Final report on the reactor pressure vessel pressurized-thermal-shock. International comparative assessment study (RPV PTS ICAS)

    International Nuclear Information System (INIS)

    Sievers, J.; Schulz, H.; Bass, R.; Pugh, C.

    1999-10-01

    A summary of the recently completed International Comparative Assessment Study of Pressurized-Thermal-Shock in Reactor Pressure Vessels (RPV PTS ICAS) is presented here to record the results in actual and comparative fashions. Within the DFM task, where account was taken of material properties and boundary conditions, reasonable agreement was obtained in linear-elastic and elastic-plastic analysis results. Linear elastic analyses and J-estimation schemes were shown to provide conservative estimates of peak crack driving force when compared with those obtained using complex three-dimensional (3D) finite element analyses. Predictions of RT NDT generally showed less scatter than that observed in crack driving force calculations due to the fracture toughness curve used for fracture assessment in the transition temperature region. Observed scatter in some analytical results could be traced mainly to a misinterpretation of the thermal expansion coefficient data given for the cladding and base metal. Also, differences in some results could be due to a quality assurance problem related to procedures for approximating the loading data given in the Problem Statement. For the PFM task, linear-elastic solutions were again shown to be conservative with respect to elastic-plastic solutions (by a factor of 2 to 4). Scatter in solutions obtained using the same computer code was generally attributable to differences in input parameters, e.g. standard deviations for the initial value of RT NDT , as well as for nickel and copper content. In the THM task, while there was a high degree of scatter during the early part of the transient, reasonable agreement in results was obtained during the latter part of the transient. Generally, the scatter was due to differences in analytical approaches used by participants, which included correlation-based engineering methods, system codes and three-dimensional computational fluids dynamics codes. Some of the models used to simulate condensation

  9. Buoyancy effects in overcooling transients calculated for the NRC pressurized thermal shock study

    International Nuclear Information System (INIS)

    Theofanous, T.G.; Iyer, K.; Nourbakhsh, H.P.; Gherson, P.

    1986-05-01

    The thermal-hydraulic responses of three PWRs (Oconee, Calvert Cliffs, and H.B. Robinson), to postulated Pressurized Thermal Shock (PTS) scenarios, which were originally determined by RELAP5 and TRAC calculations, are being further developed here with regard to buoyancy/stratification effects. These three PWRs were the subject of the NRC PTS study, and the present results helped define the thermal-hydraulic conditions utilized in the fracture mechanics calculations carried out at ORNL. The computer program REMIX, which is based on the Regional Mixing Model (RMM), was the analytical tool employed, while Purdue's 1/2-Scale HPI Thermal Mixing facility provided the basis for experimental support. Important mixing and wall heat transfer regimes are delineated on the basis of these results. We conclude that stratification is important only in cases of complete loop stagnation and that mixed-convection effects are important for downcomer flow velocities below approx.0.25 m/s. The stratification is small in magnitude, however it is important in creating a recirculating flow pattern which activates the lower plenum, pump and loop seal volumes, to participate in the mixing process. This mixing process together with the heat input from the wall metal significantly impact the cooldown rates. Heat transfer in the plume region is dominated by forced convection. On the other hand, the presence of the Reactor Pressure Vessel (RPV) wall cladding and wall conduction significantly dampen the free convection effects in the low velocity, mixed-convection, regime. For the stagnant loop cases, all locations outside the plume region are included in this regime. In the presence of natural loop circulation and a uniformly distributed downcomer flow, the mixed convection regime is also expected, however, the forced convection regime can also be observed in highly asymmetric flow behavior

  10. 3D numerical simulation of the long range propagation of acoustical shock waves through a heterogeneous and moving medium

    Energy Technology Data Exchange (ETDEWEB)

    Luquet, David; Marchiano, Régis; Coulouvrat, François, E-mail: francois.coulouvrat@upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190, Institut Jean Le Rond d’Alembert, F-75005, Paris (France)

    2015-10-28

    Many situations involve the propagation of acoustical shock waves through flows. Natural sources such as lightning, volcano explosions, or meteoroid atmospheric entries, emit loud, low frequency, and impulsive sound that is influenced by atmospheric wind and turbulence. The sonic boom produced by a supersonic aircraft and explosion noises are examples of intense anthropogenic sources in the atmosphere. The Buzz-Saw-Noise produced by turbo-engine fan blades rotating at supersonic speed also propagates in a fast flow within the engine nacelle. Simulating these situations is challenging, given the 3D nature of the problem, the long range propagation distances relative to the central wavelength, the strongly nonlinear behavior of shocks associated to a wide-band spectrum, and finally the key role of the flow motion. With this in view, the so-called FLHOWARD (acronym for FLow and Heterogeneous One-Way Approximation for Resolution of Diffraction) method is presented with three-dimensional applications. A scalar nonlinear wave equation is established in the framework of atmospheric applications, assuming weak heterogeneities and a slow wind. It takes into account diffraction, absorption and relaxation properties of the atmosphere, quadratic nonlinearities including weak shock waves, heterogeneities of the medium in sound speed and density, and presence of a flow (assuming a mean stratified wind and 3D turbulent ? flow fluctuations of smaller amplitude). This equation is solved in the framework of the one-way method. A split-step technique allows the splitting of the non-linear wave equation into simpler equations, each corresponding to a physical effect. Each sub-equation is solved using an analytical method if possible, and finite-differences otherwise. Nonlinear effects are solved in the time domain, and others in the frequency domain. Homogeneous diffraction is handled by means of the angular spectrum method. Ground is assumed perfectly flat and rigid. Due to the 3D

  11. 3D numerical simulation of the long range propagation of acoustical shock waves through a heterogeneous and moving medium

    International Nuclear Information System (INIS)

    Luquet, David; Marchiano, Régis; Coulouvrat, François

    2015-01-01

    Many situations involve the propagation of acoustical shock waves through flows. Natural sources such as lightning, volcano explosions, or meteoroid atmospheric entries, emit loud, low frequency, and impulsive sound that is influenced by atmospheric wind and turbulence. The sonic boom produced by a supersonic aircraft and explosion noises are examples of intense anthropogenic sources in the atmosphere. The Buzz-Saw-Noise produced by turbo-engine fan blades rotating at supersonic speed also propagates in a fast flow within the engine nacelle. Simulating these situations is challenging, given the 3D nature of the problem, the long range propagation distances relative to the central wavelength, the strongly nonlinear behavior of shocks associated to a wide-band spectrum, and finally the key role of the flow motion. With this in view, the so-called FLHOWARD (acronym for FLow and Heterogeneous One-Way Approximation for Resolution of Diffraction) method is presented with three-dimensional applications. A scalar nonlinear wave equation is established in the framework of atmospheric applications, assuming weak heterogeneities and a slow wind. It takes into account diffraction, absorption and relaxation properties of the atmosphere, quadratic nonlinearities including weak shock waves, heterogeneities of the medium in sound speed and density, and presence of a flow (assuming a mean stratified wind and 3D turbulent ? flow fluctuations of smaller amplitude). This equation is solved in the framework of the one-way method. A split-step technique allows the splitting of the non-linear wave equation into simpler equations, each corresponding to a physical effect. Each sub-equation is solved using an analytical method if possible, and finite-differences otherwise. Nonlinear effects are solved in the time domain, and others in the frequency domain. Homogeneous diffraction is handled by means of the angular spectrum method. Ground is assumed perfectly flat and rigid. Due to the 3D

  12. Shock recovery experiments in the range of 10 to 45 GPa - comparison of results of synthetic magnetite and terrestrial diabase

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Pesonen, L.; Deutsch, A.; Honnermann, U.

    89 /53/, Fall Meeting Supplement (2008), , GP21C-0790-GP21C-0790 ISSN 0096-3941. [American Geophysical Union Fall Meeting. 15.12.2008-19.12.2008, San Francisco] Institutional research plan: CEZ:AV0Z30130516 Keywords : shock experiments * magnetite * diabase Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verbose=0&listenv=table&application=fm08&convert=&converthl=&refinequery=&formintern=&formextern=&transquery=kohout&_lines=&multiple=0&descriptor=%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c766%7c5433%7cShock%20recovery%20experiments%20in%20the%20range%20of%2010%20to%2045%20GPa%20-%20comparison%20of%20results%20of%20synthetic%20magnetite%20and%20terrestrial%20diabase%7cHTML%7clocalhost:0%7c%2fdata%2fepubs%2fwais%2findexes%2ffm08%2ffm08%7c19257669%2019263102%20%2fdata2%2fepubs%2fwais%2fdata%2ffm08%2ffm08.txt

  13. Thermal shock studies associated with injection of emergency core coolant in pressurized water reactors

    International Nuclear Information System (INIS)

    Cheverton, R.D.; Bolt, S.E.; Iskander, S.K.

    1977-01-01

    Studies to determine the accuracy of calculational techniques for predicting crack initiation and arrest in PWR vessels due to thermal shock from ECC injection are described. The reference calculational model is reviewed, the experimental program and facilities are described, and some thermal shock experiments and results are discussed

  14. Shock-darkening in ordinary chondrites: Determination of the pressure-temperature conditions by shock physics mesoscale modeling

    Czech Academy of Sciences Publication Activity Database

    Moreau, J.; Kohout, Tomáš; Wünnemann, K.

    2017-01-01

    Roč. 52, č. 11 (2017), s. 2375-2390 ISSN 1086-9379 Institutional support: RVO:67985831 Keywords : chondrites * pressure-temperature conditions * astrophysics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.391, year: 2016

  15. Generation of ultra-high-pressure shocks by collision of a fast plasma projectile driven in the laser-induced cavity pressure acceleration scheme with a solid target

    Czech Academy of Sciences Publication Activity Database

    Badziak, J.; Rosinski, M.; Krouský, Eduard; Kucharik, M.; Liska, R.; Ullschmied, Jiří

    2015-01-01

    Roč. 22, č. 3 (2015), s. 1-11, č. článku 032709. ISSN 1070-664X R&D Projects: GA MŠk(CZ) LD14089; GA MŠk LM2010014 EU Projects: European Commission(XE) 284464 - LASERLAB-EUROPE Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser-produced plasma * ultra-high-pressure shocks * laser-induced cavity pressure acceleration Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.207, year: 2015

  16. Assessment of margins with respect to pressurized thermal shock for the 3 loop plants of the French program

    International Nuclear Information System (INIS)

    Buchalet, C.; Haussaire, P.; Houssin, B.; Vagner, J.

    1983-08-01

    Presentation of the FRAMATOME and EDF program on pressurized thermal shock which objectives are to demonstrate that present and older French reactor vessels have adequate safety margins and to provide recommendations of feasible plant specific modifications, both technically and economically. Phase I consists in a thorough analysis of pressure and temperature transients that the R.P.V. beltine could undergo during plant operations; phase II is the fracture mechanics analysis; phase III estimates the safety margins available during normal, upset, emergency and faulted conditions

  17. 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

  18. MacCormack's technique-based pressure reconstruction approach for PIV data in compressible flows with shocks

    Science.gov (United States)

    Liu, Shun; Xu, Jinglei; Yu, Kaikai

    2017-06-01

    This paper proposes an improved approach for extraction of pressure fields from velocity data, such as obtained by particle image velocimetry (PIV), especially for steady compressible flows with strong shocks. The principle of this approach is derived from Navier-Stokes equations, assuming adiabatic condition and neglecting viscosity of flow field boundaries measured by PIV. The computing method is based on MacCormack's technique in computational fluid dynamics. Thus, this approach is called the MacCormack method. Moreover, the MacCormack method is compared with several approaches proposed in previous literature, including the isentropic method, the spatial integration and the Poisson method. The effects of velocity error level and PIV spatial resolution on these approaches are also quantified by using artificial velocity data containing shock waves. The results demonstrate that the MacCormack method has higher reconstruction accuracy than other approaches, and its advantages become more remarkable with shock strengthening. Furthermore, the performance of the MacCormack method is also validated by using synthetic PIV images with an oblique shock wave, confirming the feasibility and advantage of this approach in real PIV experiments. This work is highly significant for the studies on aerospace engineering, especially the outer flow fields of supersonic aircraft and the internal flow fields of ramjets.

  19. Spatially digitized tactile pressure sensors with tunable sensitivity and sensing range.

    Science.gov (United States)

    Choi, Eunsuk; Sul, Onejae; Hwang, Soonhyung; Cho, Joonhyung; Chun, Hyunsuk; Kim, Hongjun; Lee, Seung-Beck

    2014-10-24

    When developing an electronic skin with touch sensation, an array of tactile pressure sensors with various ranges of pressure detection need to be integrated. This requires low noise, highly reliable sensors with tunable sensing characteristics. We demonstrate the operation of tactile pressure sensors that utilize the spatial distribution of contact electrodes to detect various ranges of tactile pressures. The device consists of a suspended elastomer diaphragm, with a carbon nanotube thin-film on the bottom, which makes contact with the electrodes on the substrate with applied pressure. The electrodes separated by set distances become connected in sequence with tactile pressure, enabling consecutive electrodes to produce a signal. Thus, the pressure is detected not by how much of a signal is produced but by which of the electrodes is registering an output. By modulating the diaphragm diameter, and suspension height, it was possible to tune the pressure sensitivity and sensing range. Also, adding a fingerprint ridge structure enabled the sensor to detect the periodicity of sub-millimeter grating patterns on a silicon wafer.

  20. Practical method for assessing pressure shock hazards in pipeline systems of the process industry; Praxisorientierte Vorgehensweise zur Beurteilung der Druckstossgefahren in Rohrleitungssystemen der Prozessindustrie

    Energy Technology Data Exchange (ETDEWEB)

    Thiemeier, T.; Westphal, F. [Siemens AG Automation and Drives, Prozess Sicherheit, Frankfurt am Main (Germany); Schaefer, J. [Sanofi-Aventis Deutschland GmbH, USB Sicherheit, Frankfurt am Main (Germany)

    2006-11-15

    In industrial applications where long large-diameter pipelines are required, the danger of pressure shocks and cavitation shocks is well known and is taken into account in projecting. Transient flow phenomena, however, tend to be neglected even though damage and leakages are caused by the same mechanisms also in chemical engineering processes. The contribution describes a staged procedure that makes it possible to assess the potential hazards resulting from pressure shocks in process engineering without requiring too detailed an analysis of uncritical cases. (orig.)

  1. Metabolic costs imposed by hydrostatic pressure constrain bathymetric range in the lithodid crab Lithodes maja.

    Science.gov (United States)

    Brown, Alastair; Thatje, Sven; Morris, James P; Oliphant, Andrew; Morgan, Elizabeth A; Hauton, Chris; Jones, Daniel O B; Pond, David W

    2017-11-01

    The changing climate is shifting the distributions of marine species, yet the potential for shifts in depth distributions is virtually unexplored. Hydrostatic pressure is proposed to contribute to a physiological bottleneck constraining depth range extension in shallow-water taxa. However, bathymetric limitation by hydrostatic pressure remains undemonstrated, and the mechanism limiting hyperbaric tolerance remains hypothetical. Here, we assess the effects of hydrostatic pressure in the lithodid crab Lithodes maja (bathymetric range 4-790 m depth, approximately equivalent to 0.1 to 7.9 MPa hydrostatic pressure). Heart rate decreased with increasing hydrostatic pressure, and was significantly lower at ≥10.0 MPa than at 0.1 MPa. Oxygen consumption increased with increasing hydrostatic pressure to 12.5 MPa, before decreasing as hydrostatic pressure increased to 20.0 MPa; oxygen consumption was significantly higher at 7.5-17.5 MPa than at 0.1 MPa. Increases in expression of genes associated with neurotransmission, metabolism and stress were observed between 7.5 and 12.5 MPa. We suggest that hyperbaric tolerance in L maja may be oxygen-limited by hyperbaric effects on heart rate and metabolic rate, but that L maja 's bathymetric range is limited by metabolic costs imposed by the effects of high hydrostatic pressure. These results advocate including hydrostatic pressure in a complex model of environmental tolerance, where energy limitation constrains biogeographic range, and facilitate the incorporation of hydrostatic pressure into the broader metabolic framework for ecology and evolution. Such an approach is crucial for accurately projecting biogeographic responses to changing climate, and for understanding the ecology and evolution of life at depth. © 2017. Published by The Company of Biologists Ltd.

  2. Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

    Science.gov (United States)

    Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

    2017-03-01

    In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

  3. Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

    Directory of Open Access Journals (Sweden)

    Bing-Yu Wang

    2014-11-01

    Full Text Available In this study, we develop a clamped–clamped beam-type piezoelectric vacuum pressure sensing element. The clamped–clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10−6 to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage.

  4. Ultra-low-pressure sputtering to improve exchange bias and tune linear ranges in spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Tang, XiaoLi, E-mail: tangtang1227@163.com; Yu, You; Liu, Ru; Su, Hua; Zhang, HuaiWu; Zhong, ZhiYong; Jing, YuLan

    2017-05-01

    A series of CoFe/IrMn exchange bilayers was grown by DC-sputtering at different ultra-low argon pressures ranging from 0.008 to 0.1 Pa. This pressure range was one to two orders lower than the normal sputtering pressure. Results revealed that the exchange bias increased from 140 to 250 Oe in CoFe(10 nm)/IrMn (15 nm) bilayers of fixed thickness because of the improved crystalline structure and morphological uniformity of films. Since ferromagnetic /antiferromagnetic (FM/AF) bilayers are always used in linear magnetic sensors as detection layers, the varying exchange bias can successfully achieve tunable linear range in a crossed pinning spin valve. The linear range could be adjustable from −80 Oe – +80 Oe to −150 Oe – +150 Oe on the basis of giant magnetoresistance responses. Therefore, this method provides a simple method to tune the operating range of magnetic field sensors. - Highlights: • Increasing exchange bias was achieved in bilayer at ultra-low-pressure sputtering. • The low void density and smooth surface were achieved in low pressure. • Varying exchange bias achieved tunable linear range in spin valve.

  5. High dynamic range emission measurements of shocked energetic materials: Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)

    Science.gov (United States)

    Bassett, Will P.; Dlott, Dana D.

    2016-06-01

    A new emission apparatus with high time resolution and high dynamic range was used to study shock-induced ignition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in the form of ultrafine powder (4 ± 3 μm particle size), over a range of impact velocities (0.8-4.3 km s-1) and impact durations (2.5-16 ns). A graybody model was used to extract graybody emissivities and time-dependent temperatures from a few ns to 100 μs. The emission transients consisted of three parts: a 6700 K nanosecond burst during the shocks, a 4000-4500 K temperature spike near 0.3 μs followed by a ˜3300 K tail extending out to ˜100 μs. These temperatures varied remarkably little with impact velocity and duration, while the emission intensities and emissivities changed by over an order of magnitude. The emissivity changes were interpreted with a hot spot model, where hot spot temperatures reached a maximum of 6700 K and the hot spot volume fractions increased from 5% to 100% as impact velocity increased from 1 to 3 km s-1. Changing shock durations in the 2.5-16 ns range had noticeable effects on the microsecond emission. The 0.3 μs temperature spike was much smaller or absent with 2.5 ns shocks, but prominent with longer durations. An explanation for these effects was put forth that invoked the formation of carbon-rich clusters during the shock. In this view, cluster formation was minimal with 2.5 ns shocks, but longer-duration shocks produced increasingly larger clusters, and the 0.3 μs temperature spikes represented cluster ignition.

  6. Thermal hydraulic evaluation for an experimental facility to investigate pressurized thermal shock (PTS) in CDTN/CNEN

    International Nuclear Information System (INIS)

    Palmieri, Elcio T.; Navarro, Moyses A.; Aronne, Ivam D.; Terra, Jose L.

    2002-01-01

    The goal of the work presented in this paper is to provide necessary thermal hydraulics information to the design of an experimental installation to investigate the Pressurized Thermal Shock (PTS) to be implemented at Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN). The envisaged installation has a test section that represents, in a small scale, a pressure vessel of a nuclear reactor. This test section will be heated and then exposed to a PTS in order to evaluate the appearance and development of cracks. To verify the behavior of the temperatures of the pressure vessel after a sudden flood through the annulus, calculations were made using the RELAP5/MOD 3.2.2 gamma code. Different outer radiuses were studied for the annular region. The results showed that the smaller annulus spacing (20 mm) anticipates the wetting of the surface and produces a higher cooling of the external surface, which stays completely wet for a longer time. (author)

  7. High-pressure phase transition in silicon carbide under shock loading using ultrafast x-ray diffraction

    Science.gov (United States)

    Tracy, S. J.; Smith, R. F.; Wicks, J. K.; Fratanduono, D. E.; Gleason, A. E.; Bolme, C.; Speziale, S.; Appel, K.; Prakapenka, V. B.; Fernandez Panella, A.; Lee, H. J.; MacKinnon, A.; Eggert, J.; Duffy, T. S.

    2017-12-01

    The behavior of silicon carbide (SiC) under shock loading was investigated through a series of time-resolved pump-probe x-ray diffraction (XRD) measurements. SiC is found at impact sites and has been put forward as a possible constituent in the proposed class of extra-solar planets known as carbon planets. Previous studies have used wave profile measurements to identify a phase transition under shock loading near 1 Mbar, but crystal structure information was not obtained. We have carried out an in situ XRD study of shock-compressed SiC using the Matter in Extreme Conditions instrument of the Linac Coherent Light Source. The femtosecond time resolution of the x-ray free electron laser allows for the determination of time-dependent atomic arrangements during shock loading and release. Two high-powered lasers were used to generate ablation-driven compression waves in the samples. Time scans were performed using the same drive conditions and nominally identical targets. For each shot in a scan, XRD data was collected at a different probe time after the shock had entered the SiC. Probe times extended up to 40 ns after release. Scans were carried out for peak pressures of 120 and 185 GPa. Our results demonstrate that SiC transforms directly from the ambient tetrahedrally-coordinated phase to the octahedral B1 structure on the nanosecond timescale of laser-drive experiments and reverts to the tetrahedrally coordinated ambient phase within nanoseconds of release. The data collected at 120 GPa exhibit diffraction peaks from both compressed ambient phase and transformed B1 phase, while the data at 185 GPa show a complete transformation to the B1 phase. Densities determined from XRD peaks are in agreement with an extrapolation of previous continuum data as well as theoretical predictions. Additionally, a high degree of texture was retained in both the high-pressure phase as well as on back transformation. Two-dimensional fits to the XRD data reveal details of the

  8. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. I - Pressure distribution

    Science.gov (United States)

    Messiter, A. F.

    1980-01-01

    Asymptotic solutions are derived for the pressure distribution in the interaction of a weak normal shock wave with a turbulent boundary layer. The undisturbed boundary layer is characterized by the law of the wall and the law of the wake for compressible flow. In the limiting case considered, for 'high' transonic speeds, the sonic line is very close to the wall. Comparisons with experiment are shown, with corrections included for the effect of longitudinal wall curvature and for the boundary-layer displacement effect in a circular pipe.

  9. The computation of pressure waves in shock tubes by a finite difference procedure

    International Nuclear Information System (INIS)

    Barbaro, M.

    1988-09-01

    A finite difference solution of one-dimensional unsteady isentropic compressible flow equations is presented. The computer program has been tested by solving some cases of the Riemann shock tube problem. Predictions are in good agreement with those presented by other authors. Some inaccuracies may be attributed to the wave smearing consequent of the finite-difference treatment. (author)

  10. [The predictive value of dynamic arterial elastance in arterial pressure response after norepinephrine dosage reduction in patients with septic shock].

    Science.gov (United States)

    Liang, F M; Yang, T; Dong, L; Hui, J J; Yan, J

    2017-05-01

    Objective: To assess whether dynamic arterial elastance(Ea(dyn))can be used to predict the reduction of arterial pressure after decreasing norepinephrine (NE) dosage in patients with septic shock. Methods: A prospective observational cohort study was conducted. Thirty-two patients with septic shock and mechanical ventilationwere enrolledfrom January 2014 to December 2015 in ICU of Wuxi People's Hospital of Nanjing Medical University. Hemodynamic parameters were recorded by pulse contour cardiac output(PiCCO)monitoring technology before and after decreasing norepinephrine dosage. Ea(dyn) was defined as the ratio of pulse pressure variation (PPV) to stroke volume variation (SVV). Mean arterial pressure(MAP) variation was calculated after decreasing the dose of NE. Response was defined as a ≥15% decrease of MAP. AUC was plotted to assess the value of Ea(dyn) in predicting MAP response. Results: A total of 32 patients were enrolled in our study, with 13 responding to NE dose decrease where as the other 19 did not. Ea(dyn) was lower in responders than in nonresponders (0.77±0.13 vs 1.09±0.31, P blood pressure variation, diastolic blood pressure variation, systemic vascular resistance variation and MAP variation( r =0.621, P =0.000; r =0.735, P =0.000; r =0.756, P =0.000; r =0.568, P =0.000 respectively). However, stoke volume variation, baseline level of systemic vascular resistance and NE baseline dose were not correlated with Ea(dyn) baseline value( r =0.264, P =0.076; r =0.078, P =0.545; r =0.002, P =0.987 respectively). Ea(dyn)≤0.97 predicted a decrease of MAP when decreasing NE dose, with an area under the receiver-operating characteristic curve of 0.85.The sensitivity was 100.0% and specificity was 73.7%. Conclusions: In septic shock patients treated with NE, Ea(dyn) is an index to predict the decrease of arterial pressure in response to NE dose reduction.

  11. On the Accurate Determination of Shock Wave Time-Pressure Profile in the Experimental Models of Blast-Induced Neurotrauma

    Directory of Open Access Journals (Sweden)

    Maciej Skotak

    2018-02-01

    Full Text Available Measurement issues leading to the acquisition of artifact-free shock wave pressure-time profiles are discussed. We address the importance of in-house sensor calibration and data acquisition sampling rate. Sensor calibration takes into account possible differences between calibration methodology in a manufacturing facility, and those used in the specific laboratory. We found in-house calibration factors of brand new sensors differ by less than 10% from their manufacturer supplied data. Larger differences were noticeable for sensors that have been used for hundreds of experiments and were as high as 30% for sensors close to the end of their useful lifetime. These observations were despite the fact that typical overpressures in our experiments do not exceed 50 psi for sensors that are rated at 1,000 psi maximum pressure. We demonstrate that sampling rate of 1,000 kHz is necessary to capture the correct rise time values, but there were no statistically significant differences between peak overpressure and impulse values for low-intensity shock waves (Mach number <2 at lower rates. We discuss two sources of experimental errors originating from mechanical vibration and electromagnetic interference on the quality of a waveform recorded using state-of-the-art high-frequency pressure sensors. The implementation of preventive measures, pressure acquisition artifacts, and data interpretation with examples, are provided in this paper that will help the community at large to avoid these mistakes. In order to facilitate inter-laboratory data comparison, common reporting standards should be developed by the blast TBI research community. We noticed the majority of published literature on the subject limits reporting to peak overpressure; with much less attention directed toward other important parameters, i.e., duration, impulse, and dynamic pressure. These parameters should be included as a mandatory requirement in publications so the results can be properly

  12. Use of Z pinch radiation sources for high pressure shock wave studies

    International Nuclear Information System (INIS)

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Trott, W.M.; Chandler, G.A.; Holland, K.G.; Fleming, K.J.; Trucano, T.G.

    1998-01-01

    Recent developments in pulsed power technology demonstrate use of intense radiation sources (Z pinches) for driving planar shock waves in samples with spatial dimensions larger than possible with other radiation sources. Initial indications are that the use of Z pinch sources can be used to produce planar shock waves in samples with diameters of a few millimeters and thicknesses approaching one half millimeter. These dimensions allow increased accuracy of both shock velocity and particle velocity measurements. The Z pinch radiation source uses imploding metal plasma induced by self-magnetic fields applied to wire arrays to produce high temperature x-ray environments in vacuum hohlraum enclosures. Previous experiments have demonstrated that planar shock waves can be produced with this approach. A photograph of a wire array located inside the vacuum hohlraum is shown here. Typically, a few hundred individual wires are used to produce the Z pinch source. For the shock wave experiments being designed, arrays of 120 to 240 tungsten wires with a diameter of 40 mm and with individual diameters of about 10 microm are used. Preliminary experiments have been performed on the Z pulsed radiation source to demonstrate the ability to obtain VISAR measurements in the Z accelerator environment. Analysis of these results indicate that another effect, not initially anticipated, is an apparent change in refractive index that occurs in the various optical components used in the system. This effect results in an apparent shift in the frequency of reflected laser light, and causes an error in the measured particle velocity. Experiments are in progress to understand and minimize this effect

  13. A Newly Designed Fiber-Optic Based Earth Pressure Transducer with Adjustable Measurement Range

    Directory of Open Access Journals (Sweden)

    Hou-Zhen Wei

    2018-03-01

    Full Text Available A novel fiber-optic based earth pressure sensor (FPS with an adjustable measurement range and high sensitivity is developed to measure earth pressures for civil infrastructures. The new FPS combines a cantilever beam with fiber Bragg grating (FBG sensors and a flexible membrane. Compared with a traditional pressure transducer with a dual diaphragm design, the proposed FPS has a larger measurement range and shows high accuracy. The working principles, parameter design, fabrication methods, and laboratory calibration tests are explained in this paper. A theoretical solution is derived to obtain the relationship between the applied pressure and strain of the FBG sensors. In addition, a finite element model is established to analyze the mechanical behavior of the membrane and the cantilever beam and thereby obtain optimal parameters. The cantilever beam is 40 mm long, 15 mm wide, and 1 mm thick. The whole FPS has a diameter of 100 mm and a thickness of 30 mm. The sensitivity of the FPS is 0.104 kPa/με. In addition, automatic temperature compensation can be achieved. The FPS’s sensitivity, physical properties, and response to applied pressure are extensively examined through modeling and experiments. The results show that the proposed FPS has numerous potential applications in soil pressure measurement.

  14. An optimal frequency range for assessing the pressure reactivity index in patients with traumatic brain injury.

    Science.gov (United States)

    Howells, Tim; Johnson, Ulf; McKelvey, Tomas; Enblad, Per

    2015-02-01

    The objective of this study was to identify the optimal frequency range for computing the pressure reactivity index (PRx). PRx is a clinical method for assessing cerebral pressure autoregulation based on the correlation of spontaneous variations of arterial blood pressure (ABP) and intracranial pressure (ICP). Our hypothesis was that optimizing the methodology for computing PRx in this way could produce a more stable, reliable and clinically useful index of autoregulation status. The patients studied were a series of 131 traumatic brain injury patients. Pressure reactivity indices were computed in various frequency bands during the first 4 days following injury using bandpass filtering of the input ABP and ICP signals. Patient outcome was assessed using the extended Glasgow Outcome Scale (GOSe). The optimization criterion was the strength of the correlation with GOSe of the mean index value over the first 4 days following injury. Stability of the indices was measured as the mean absolute deviation of the minute by minute index value from 30-min moving averages. The optimal index frequency range for prediction of outcome was identified as 0.018-0.067 Hz (oscillations with periods from 55 to 15 s). The index based on this frequency range correlated with GOSe with ρ=-0.46 compared to -0.41 for standard PRx, and reduced the 30-min variation by 23%.

  15. Collision of two shock waves as a hypothetical mechanism of producing drifting radio bursts in the 400-500 MHz range

    International Nuclear Information System (INIS)

    Karlicky, M.

    1978-01-01

    After the proton flare of July 3, 1974 a hitherto unclassified phenomenon with a diffusion ''banner'' and with a considerably decelerating drift within the type II and III burst drifts range was observed in the radio dynamic spectrum between 410 and 470 MHz. The hypothesis is presented that the phenomenon is due to the collision of two shock waves, propagating against one another, during which the flux of electromagnetic radiation is considerably enhanced relative to the sum of the fluxes of the electromagnetic radiation of the individual shock waves. The Newkirk 4-density model of the corona is used to describe the phenomenon, the mechanism of plasmon-plasmon conversion in electromagnetic radiation with a double plasma frequency is considered and, according to the parameters derived from the dynamic spectrum, the velocities, radii of curvature and direction of propagation of the anticipated shock waves are analysed in a simplifed symmetric case. (author)

  16. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    expanded beam of a Q-switched laser pulse at wavelength of λ=532 nm and with pulse duration of ∼4 ns is focused at the center of a water tank using an aberration minimized lens design. Single cavitation bubbles are initiated via optical breakdown at this location which coincides with the position of which the shock wave is focused. The energy of the shock wave source has been altered in 8 steps. The pressure pulse amplitude of the impinging shock wave measured at the distance of about 1.8 mm above the focus location range from 24.4 MPa to 108.1 MPa. The lithotripter shock wave impact time is varied in three steps which provides the possibility of investigation of the bubble dynamics in both cases of collapsing and expanding cavities at the moment of the shock wave impingement. After the shock wave impact, the bubble spherical symmetry is broken and a liquid jet develops in the original direction of the shock propagation. The speed of the jet is increasing with the shock wave energy. Due to the energy transfer from the shock wave to the bubble, the forced cavity implosion is more violent in comparison to free oscillation. The pressure pulse amplitude released from the forced bubble collapse is amplified and the collapse time is reduced. These effects are discussed in chapter 5. Generally, when the bubble is collapsing at the time of the shock impact, the forced cavity collapse is more violent with a resultant of more pressure enhancement compared to the expanding bubbles at the moment of the shock arrival. The maximum pressure enhancement and reduction of bubble collapse time occur when the time interval between the moments of the shock impact and bubble collapse approaches the pulse duration of the compression part of the shock wave profile (i.e. ∼1 μs). For each specific shock wave arrival time, increasing the shock intensity leads to the fact that the bubble collapse takes place earlier relative to the moment of the shock impact and having more collapse pressure

  17. 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

  18. Use of IR pyrometry to measure free-surface temperatures of partially melted tin as a function of shock pressure

    International Nuclear Information System (INIS)

    Seifter, A.; Furlanetto, M. R.; Holtkamp, D. B.; Obst, A. W.; Payton, J. R.; Stone, J. B.; Tabaka, L. J.; Grover, M.; Macrum, G. S.; Stevens, G. D.; Turley, W. D.; Swift, D. C.; Veeser, L. R.

    2009-01-01

    Equilibrium equation of state theory predicts that the free-surface release temperature of shock-loaded tin will show a plateau at 505 K in the stress range from 19.5 to 33.0 GPa, corresponding to the solid-liquid, mixed-phase region of tin. In this paper we report free-surface temperature measurements on shock-loaded tin from 15 to 31 GPa using multiwavelength optical pyrometry. The shock waves were generated by direct contact of detonating high explosive with a tin sample, and the stress in the sample was determined by free-surface velocity measurements using photon Doppler velocimetry. We measured the emitted thermal radiance in the near IR region at four wavelengths from 1.5 to 5.0 μm. Above 25 GPa the measured free-surface temperatures were higher than the predicted 505 K, and they increased with increasing stress. This deviation may be explained by hot spots and/or variations in surface emissivity, and it may indicate a weakness in the use of a simple analysis of multiwavelength pyrometry data for conditions, such as above the melt threshold, where hot spots or emissivity variations may be significant. We are continuing to study the discrepancy to determine its cause.

  19. Large dynamic range pressure sensor based on two semicircle-holes microstructured fiber.

    Science.gov (United States)

    Liu, Zhengyong; Htein, Lin; Lee, Kang-Kuen; Lau, Kin-Tak; Tam, Hwa-Yaw

    2018-01-08

    This paper presents a sensitive and large dynamic range pressure sensor based on a novel birefringence microstructured optical fiber (MOF) deployed in a Sagnac interferometer configuration. The MOF has two large semicircle holes in the cladding and a rectangular strut with germanium-doped core in the center. The fiber structure permits surrounding pressure to induce large effective index difference between the two polarized modes. The calculated and measured group birefringence of the fiber are 1.49 × 10 -4 , 1.23 × 10 -4 , respectively, at the wavelength of 1550 nm. Experimental results shown that the pressure sensitivity of the sensor varied from 45,000 pm/MPa to 50,000 pm/MPa, and minimum detectable pressure of 80 Pa and dynamic range of better than 116 dB could be achieved with the novel fiber sensor. The proposed sensor could be used in harsh environment and is an ideal candidate for downhole applications where high pressure measurement at elevated temperature up to 250 °C is needed.

  20. Pressurized thermal shock. CNA-I behavior when a hot leg breaks of 50 cm2 is produced

    International Nuclear Information System (INIS)

    Rosso, Ricardo D.; Ventura, Mirta A.

    2002-01-01

    Pressurized thermal shock (PTS) phenomena in the CNA-I pressurize heavy water reactor is analyzed in this paper. The initiating event is a hypothetical 50 cm 2 break of the line connecting the pressurizer and the primary system. The calculation procedure for obtaining the local thermal-hydraulic parameters in the reactor pressure vessel downcomer is described firstly. Results obtained lead to conclusions in different subjects. The first conclusion is that a simple tool of easy application is available to analyze PTS phenomena in cases of breaks in the primary system in cold and hot legs. This methodology is fully independent of the methodology utilized by the Utility. Another important conclusion comes from the analysis of the temperature evolution of the fluid below the cold leg level in the RPV downcomer, as a function of the T HPI temperature of the TJ system injected water from. It is also concluded that the results obtained with the methodology adopted agree with the ones obtained with the methodologies validated against experiments in the UPTF facility. It is possible to observe that when T HPI increase, the conditions suitable for PTS occurrence in a LOCA accident tend to diminish. The maximum value to the T HPI may be fixed from the maximum temperature allowed to preserve the structural integrity of the fuel cladding. (author)

  1. Hypertonic/Hyperoncotic Resuscitation from Shock: Reduced Volume Requirement and Lower Intracranial Pressure

    Science.gov (United States)

    1989-10-01

    Fig. I A-I). Cerebro ~.iscular 4. and svsternic hcmodsnarmc to!- ’. -lowing resuscitation ’from hem- orrhagic shock in the presence S2- / 4 of a...intratranial mass in dogs Cerebro - %uscular effects of resuscitation fluid choices Ancsth Analg 6’ 259 763 2tW ?%5..Cg -- ’ 384 CRITICAL CARE MEDICINE...184, 1967 8. Prior PF, Maynard DE, Brierley JB: E.E.G. monitoring for the control of anaesthesia produced by the infusion of althesin in primates . Br

  2. Limits of deuterium pressure range with neutron production in plasma focus devices

    International Nuclear Information System (INIS)

    Pouzo, J.; Milanese, M.; Piriz, R.; Cortazar, D.; Moroso, R.

    1988-01-01

    In this work we present the experimental curves of neutron yield (Y) respect to the deuterium filling pressure (p) obtained in our plasma focuses device PACO. Y increases with the focus current (I f ) according with the scaling law Y ∼I 4-5 f , but it presents a limited range of p beyond which Y drastically decreases. The higher pressure limit is coincident with recently reported limit due to the energy available to maintain the ionization rate of the neutral gas during the roll-off stage. The lower pressure limit is here explained, through experimental evidences, in terms of a phenomenon connected with the dynamics of the current sheath (cs) during the roll-off stage. (author). 8 refs, 11 figs

  3. Computer calculation of heat capacity of natural gases over a wide range of pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dranchuk, P.M. (Alberta Univ., Edmonton, AB (Canada)); Abou-Kassem, J.H. (Pennsylvania State Univ., University Park, PA (USA))

    1992-04-01

    A method is presented whereby specific heats or heat capacities of natural gases, both sweet and sour, at elevated pressures and temperatures may be made suitable to modern-day machine calculation. The method involves developing a correlation for ideal isobaric heat capacity as a function of gas gravity and pseudo reduced temperature over the temperature range of 300 to 1500 K, and a mathematical equation for the isobaric heat capacity departure based on accepted thermodynamic principles applied to an equation of state that adequately describes the behavior of gases to which the Standing and Katz Z factor correlation applies. The heat capacity departure equation is applicable over the range of 0.2 {le} Pr {le} 15 and 1.05 {le} Tr {le} 3, where Pr and Tr refer to the reduced pressure and temperature respectively. The significance of the method presented lies in its utility and adaptability to computer applications. 25 refs., 2 figs., 4 tabs.

  4. Two-phase pressurized thermal shock investigations using a 3D two-fluid modeling of stratified flow with condensation

    International Nuclear Information System (INIS)

    Yao, W.; Coste, P.; Bestion, D.; Boucker, M.

    2003-01-01

    In this paper, a local 3D two-fluid model for a turbulent stratified flow with/without condensation, which can be used to predict two-phase pressurized thermal shock, is presented. A modified turbulent K- model is proposed with turbulence production induced by interfacial friction. A model of interfacial friction based on a interfacial sublayer concept and three interfacial heat transfer models, namely, a model based on the small eddies controlled surface renewal concept (HDM, Hughes and Duffey, 1991), a model based on the asymptotic behavior of the Eddy Viscosity (EVM), and a model based on the Interfacial Sublayer concept (ISM) are implemented into a preliminary version of the NEPTUNE code based on the 3D module of the CATHARE code. As a first step to apply the above models to predict the two-phase thermal shock, the models are evaluated by comparison of calculated profiles with several experiments: a turbulent air-water stratified flow without interfacial heat transfer; a turbulent steam-water stratified flow with condensation; turbulence induced by the impact of a water jet in a water pool. The prediction results agree well with the experimental data. In addition, the comparison of three interfacial heat transfer models shows that EVM and ISM gave better prediction results while HDM highly overestimated the interfacial heat transfers compared to the experimental data of a steam water stratified flow

  5. Modified quadrupole mass analyzer RGA-100 for beam plasma research in forevacuum pressure range

    Energy Technology Data Exchange (ETDEWEB)

    Zolotukhin, D. B.; Tyunkov, A. V. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Yushkov, Yu. G., E-mail: yuyushkov@gmail.com [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation); Oks, E. M. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Institute of High Current Electronics SB RAS, 2/3, Akademichesky Ave., Tomsk 634055 (Russian Federation)

    2015-12-15

    The industrial quadrupole RGA-100 residual gas analyzer was modified for the research of electron beam-generated plasma at forevacuum pressure range. The standard ionizer of the RGA-100 was replaced by three electrode extracting unit. We made the optimization of operation parameters in order to provide the maximum values of measured currents of any ion species. The modified analyzer was successfully tested with beam plasma of argon, nitrogen, oxygen, and hydrocarbons.

  6. TRAC-PF1 analyses of potential pressurized-thermal-shock transients at a Combustion-Engineering PWR

    International Nuclear Information System (INIS)

    Koenig, J.E.; Spriggs, G.D.; Smith, R.C.

    1984-01-01

    Los Alamos is participating in a program to assess the risk of pressurized thermal shock (PTS) to a reactor vessel. Our role is to provide best-estimate thermal-hydraulic analyses of 12 postulated overcooling transients using TRAC-PF1. These transients are hypothetical and include multiple operator/equipment failures. Calvert Cliffs/Unit-1, a Combustion-Engineering plant, is the pressurized water reactor modeled for this study. The utility and the vendor supplied information for the comprehensive TRAC-PF1 model. Secondary and primary breaks from both hot-zero-power and full-power conditions were simulated for 7200 s (2 h). Low bulk temperatures and loop-flow stagnation while the system was at a high pressure were of particular interest for PTS analysis. Three transients produced primary temperatures below 405 K (270 0 F - the NRC screening criterion) with system repressurization. Six transients indicated flow stagnation would occur in one loop but not both. One transient showed flow stagnation might occur in both loops. Oak Ridge National Laboratory will do fracture-mechanics analysis using these TRAC-PF1 results and make the final determination of the risk of PTS

  7. X-ray absorption radiography for high pressure shock wave studies

    Science.gov (United States)

    Antonelli, L.; Atzeni, S.; Batani, D.; Baton, S. D.; Brambrink, E.; Forestier-Colleoni, P.; Koenig, M.; Le Bel, E.; Maheut, Y.; Nguyen-Bui, T.; Richetta, M.; Rousseaux, C.; Ribeyre, X.; Schiavi, A.; Trela, J.

    2018-01-01

    The study of laser compressed matter, both warm dense matter (WDM) and hot dense matter (HDM), is relevant to several research areas, including materials science, astrophysics, inertial confinement fusion. X-ray absorption radiography is a unique tool to diagnose compressed WDM and HDM. The application of radiography to shock-wave studies is presented and discussed. In addition to the standard Abel inversion to recover a density map from a transmission map, a procedure has been developed to generate synthetic radiographs using density maps produced by the hydrodynamics code DUED. This procedure takes into account both source-target geometry and source size (which plays a non negligible role in the interpretation of the data), and allows to reproduce transmission data with a good degree of accuracy.

  8. Valuation of Normal Range of Ankle Systolic Blood Pressure in Subjects with Normal Arm Systolic Blood Pressure.

    Science.gov (United States)

    Gong, Yi; Cao, Kai-wu; Xu, Jin-song; Li, Ju-xiang; Hong, Kui; Cheng, Xiao-shu; Su, Hai

    2015-01-01

    This study aimed to establish a normal range for ankle systolic blood pressure (SBP). A total of 948 subjects who had normal brachial SBP (90-139 mmHg) at investigation were enrolled. Supine BP of four limbs was simultaneously measured using four automatic BP measurement devices. The ankle-arm difference (An-a) on SBP of both sides was calculated. Two methods were used for establishing normal range of ankle SBP: the 99% method was decided on the 99% reference range of actual ankle BP, and the An-a method was the sum of An-a and the low or up limits of normal arm SBP (90-139 mmHg). Whether in the right or left side, the ankle SBP was significantly higher than the arm SBP (right: 137.1 ± 16.9 vs 119.7 ± 11.4 mmHg, P<0.05). Based on the 99% method, the normal range of ankle SBP was 94~181 mmHg for the total population, 84~166 mmHg for the young (18-44 y), 107~176 mmHg for the middle-aged(45-59 y) and 113~179 mmHg for the elderly (≥ 60 y) group. As the An-a on SBP was 13 mmHg in the young group and 20 mmHg in both middle-aged and elderly groups, the normal range of ankle SBP on the An-a method was 103-153 mmHg for young and 110-160 mmHg for middle-elderly subjects. A primary reference for normal ankle SBP was suggested as 100-165 mmHg in the young and 110-170 mmHg in the middle-elderly subjects.

  9. Time to achieve target mean arterial pressure during resuscitation from experimental anaphylactic shock in an animal model. A comparison of adrenaline alone or in combination with different volume expanders.

    Science.gov (United States)

    Tajima, K; Zheng, F; Collange, O; Barthel, G; Thornton, S N; Longrois, D; Levy, B; Audibert, G; Malinovsky, J M; Mertes, P M

    2013-11-01

    Anaphylactic shock is a rare, but potentially lethal complication, combining life-threatening circulatory failure and massive fluid shifts. Treatment guidelines rely on adrenaline and volume expansion by intravenous fluids, but there is no solid evidence for the choice of one specific type of fluid over another. Our purpose was to compare the time to achieve target mean arterial pressure upon resuscitation using adrenaline alone versus adrenaline with different resuscitation fluids in an animal model and to compare the tissue oxygen pressures (PtiO2) with the various strategies. Twenty-five ovalbumin-sensitised Brown Norway rats were allocated to five groups after anaphylactic shock induction: vehicle (CON), adrenaline alone (AD), or adrenaline with isotonic saline (AD+IS), hydroxyethyl starch (AD+HES) or hypertonic saline (AD+HS). Time to reach a target mean arterial pressure value of 75 mmHg, cardiac output, skeletal muscle PtiO2, lactate/pyruvate ratio and cumulative doses of adrenaline were recorded. Non-treated rats died within 15 minutes. The target mean arterial pressure value was reached faster with AD+HES (median: 10 minutes, range: 7.5 to 12.5 minutes) and AD+IS (median: 17.5 minutes, range: 5 to 25 minutes) versus adrenaline alone (median: 25 minutes, range: 20-30 minutes). There were also reduced adrenaline requirements in these groups. The skeletal muscle PtiO2 was restored only in the AD+HES group. Although direct extrapolation to humans should be made with caution, our results support the combined use of adrenaline and volume expansion for resuscitation from anaphylactic shock. When used with adrenaline the most effective fluid was hydroxyethyl starch, whereas hypertonic saline was the least effective.

  10. Standing shocks in magnetized dissipative accretion flow around ...

    Indian Academy of Sciences (India)

    BIPLOB SARKAR

    2018-02-09

    Feb 9, 2018 ... flow around a black hole admits shock when the flow parameters are tuned for a considerable range. ... not exceed the gas pressure (Pgas) since the magnetic flux will ..... rily characterizes the spectral and temporal behaviour.

  11. Shock wave propagation in neutral and ionized gases

    International Nuclear Information System (INIS)

    Podder, N. K.; Wilson IV, R. B.; Bletzinger, P.

    2008-01-01

    Preliminary measurements on a recently built shock tube are presented. Planar shock waves are excited by the spark discharge of a capacitor, and launched into the neutral argon or nitrogen gas as well as its ionized glow discharge in the pressure region 1-17 Torr. For the shock wave propagation in the neutral argon at fixed capacitor charging voltage, the shock wave velocity is found to increase nonlinearly at the lower pressures, reach a maximum at an intermediate pressure, and then decrease almost linearly at the higher pressures, whereas the shock wave strength continues to increase at a nonlinear rate over the entire range of pressure. However, at fixed gas pressure the shock wave velocity increases almost monotonically as the capacitor charging voltage is increased. For the shock wave propagation in the ionized argon glow, the shock wave is found to be most influenced by the glow discharge plasma current. As the plasma current is increased, both the shock wave propagation velocity and the dispersion width are observed to increase nonlinearly

  12. 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.

  13. Development of in-situ laser based cutting technique for shock absorber rear nut in pressurized heavy water reactors. CP-2.1

    International Nuclear Information System (INIS)

    Vishwakarma, S.C.; Jain, R.K.; Upadhyaya, B.N.; Choubey, Ambar; Agrawal, D.K.; Oak, S.M.

    2007-01-01

    We have developed a laser based cutting technique for shock absorber rear nuts in pressurized heavy water reactors (PHWRs). This technique has been successfully used for in-situ laser cutting at RAPS-3 reactor. The technique consists of a motorized compact fixture, which holds a fiber optic beam delivery cutting nozzle and can be operated remotely

  14. Shakedown and stress range of torispherical heads under cyclic internal pressure

    International Nuclear Information System (INIS)

    Kalnins, A.; Updike, D.P.

    1996-01-01

    Two effects on shakedown of torispherical heads are addressed in this paper: (1) changing geometry, and (2) initial pressurization, such as by a hydro (or proof) test. Shakedown and the cycled stress intensity range are calculated for two head geometries, having diameter-to-thickness ratios of 238 and 192. The calculations are carried out following two approaches: (1) using a nonlinear, elastic-plastic algorithm that accounts for changes in geometry, and (2) using elastic stresses in the undeformed geometry, which is the commonly used approach. The results show that, when the two geometries are subjected to the same initial and cyclic pressures, shakedown is achieved by the first approach but not by the second. Since real heads do benefit from geometry changes, and since most design codes require hydro (or proof) tests before operation, the first approach is recommended for the design of torispherical heads

  15. 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.

  16. Dynamic Pressure of Liquid Mercury Target During 800-MeV Proton Thermal Shock Tests

    International Nuclear Information System (INIS)

    Allison, S.W.; Andriulli, J.B.; Cates, M.R.; Earl, D.D.; Haines, J.R.; Morrissey, F.X.; Tsai, C.C.; Wender, S.

    2000-01-01

    Described here are efforts to diagnose transient pressures generated by a short-pulse (about 0.5 microseconds) high intensity proton (∼ 2 * 10 14 per pulse) beam. Proton energy is 800-MeV. The tests were performed at the Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE-WNR). Such capability is required for understanding target interaction for the Spallation Neutron Source project as described previously at this conference.1-4 The main approach to effect the pressure measurements utilized the deflection of a diaphragm in intimate contact with the mercury. There are a wide variety of diaphragm-deflection methods used in scientific and industrial applications. Many deflection-sensing approaches are typically used, including, for instance, capacitive and optical fiber techniques. It was found, however, that conventional pressure measurement using commercial pressure gages with electrical leads was not possible due to the intense nuclear radiation environment. Earlier work with a fiber optic strain gauge demonstrated the viability of using fiber optics for this environment

  17. Full-field peak pressure prediction of shock waves from underwater explosion of cylindrical charges

    NARCIS (Netherlands)

    Liu, Lei; Guo, Rui; Gao, Ke; Zeng, Ming Chao

    2017-01-01

    Cylindrical charge is a main form in most application of explosives. By employing numerical calculation and an indirect mapping method, the relation between peak pressures from underwater explosion of cylindrical and spherical charges is investigated, and further a model to predict full-field peak

  18. Evaluating piezo-electric transducer response to thermal shock from in-cilinder pressure data

    NARCIS (Netherlands)

    Baert, R.S.G.; Rosseel, E.; Sierens, R.

    1999-01-01

    One of the major effects limiting the accuracy of piezoelectric transducers for performing in-cylinder pressure measurements is their sensitivity to the cyclic thermal loading effects of the intermittent combustion process. This paper compares five different methods for evaluating the effect of this

  19. Modelling of the dual frequency capacitive sheath in the intermediate pressure range

    International Nuclear Information System (INIS)

    Boyle, P C; Robiche, J; Turner, M M

    2004-01-01

    The nonlinearity of the plasma sheath in dual frequency capacitively coupled reactors is investigated for frequencies well above the ion plasma frequency. This work focuses on the behaviour of the voltage and the sheath width with respect to the driving current source and the collisionality regime. For typical plasma processing applications, the gas pressure ranges from a few milliTorrs to hundreds of milliTorrs, and the ion dynamics span different collisional regimes. To describe these different ion dynamics, we have used a collisionless model and a variable mobility model. The sheath widths and the voltages obtained from these two models have then been compared

  20. Software for X-Ray Images Calculation of Hydrogen Compression Device in Megabar Pressure Range

    Science.gov (United States)

    Egorov, Nikolay; Bykov, Alexander; Pavlov, Valery

    2007-06-01

    Software for x-ray images simulation is described. The software is a part of x-ray method used for investigation of an equation of state of hydrogen in a megabar pressure range. A graphical interface that clearly and simply allows users to input data for x-ray image calculation: properties of the studied device, parameters of the x-ray radiation source, parameters of the x-ray radiation recorder, the experiment geometry; to represent the calculation results and efficiently transmit them to other software for processing. The calculation time is minimized. This makes it possible to perform calculations in a dialogue regime. The software is written in ``MATLAB'' system.

  1. 10 CFR 50.61 - Fracture toughness requirements for protection against pressurized thermal shock events.

    Science.gov (United States)

    2010-01-01

    ... Mechanical Engineers Boiler and Pressure Vessel Code, Section III, Division I, “Rules for the Construction of...: ΔRTNDT = (CF)f(0.28−0.10 log f) (A) CF (°F) is the chemistry factor, which is a function of copper and... differences in copper and nickel content by multiplying them by the ratio of the chemistry factor for the...

  2. Estimating average shock pressures recorded by impactite samples based on universal stage investigations of planar deformation features in quartz - Sources of error and recommendations

    Science.gov (United States)

    Holm-Alwmark, S.; Ferrière, L.; Alwmark, C.; Poelchau, M. H.

    2018-01-01

    Planar deformation features (PDFs) in quartz are the most widely used indicator of shock metamorphism in terrestrial rocks. They can also be used for estimating average shock pressures that quartz-bearing rocks have been subjected to. Here we report on a number of observations and problems that we have encountered when performing universal stage measurements and crystallographically indexing of PDF orientations in quartz. These include a comparison between manual and automated methods of indexing PDFs, an evaluation of the new stereographic projection template, and observations regarding the PDF statistics related to the c-axis position and rhombohedral plane symmetry. We further discuss the implications that our findings have for shock barometry studies. Our study shows that the currently used stereographic projection template for indexing PDFs in quartz might induce an overestimation of rhombohedral planes with low Miller-Bravais indices. We suggest, based on a comparison of different shock barometry methods, that a unified method of assigning shock pressures to samples based on PDFs in quartz is necessary to allow comparison of data sets. This method needs to take into account not only the average number of PDF sets/grain but also the number of high Miller-Bravais index planes, both of which are important factors according to our study. Finally, we present a suggestion for such a method (which is valid for nonporous quartz-bearing rock types), which consists of assigning quartz grains into types (A-E) based on the PDF orientation pattern, and then calculation of a mean shock pressure for each sample.

  3. Re-evaluation of the technical basis for the regulation of pressurized thermal shock in U.S. pressurized water reactor vessels

    Energy Technology Data Exchange (ETDEWEB)

    Malik, S.N.; Kirk, M.T.; Jackson, D.A.; Hackett, E.M.; Chokshi, N.C.; Siu, N.O.; Woods, H.W.; Bessette, D.E. [Office of Nuclear Regulatory Research, U.S. nuclear Regulatory Commission, Washington, D.C. (United States); Dickson, T.L. [Oak Ridge National Lab., Computational Physics and Engineering Div., Oak Ridge, TN (United States)

    2001-07-01

    The current federal regulation to insure that pressurized-water nuclear reactor pressure vessels (RPVs) maintain their structural integrity when subjected to potential pressurized thermal shock (PTS) events during the life of the plant were derived from computational models and technologies that were developed in the early-to-mid 1980's. Since that time, there have been several advancements and refinements to the relevant fracture technology, materials characterization methods, probabilistic risk assessment (PRA) and thermal-hydraulics (TH) computational methods. Preliminary studies performed in 1998 (that applied this new technology) indicated the potential that technical bases can be established to support a relaxation of the current federal regulation (10 CFR 50.61) for PTS. A revision of PTS regulation could have significant implications for plants reaching their end-of-license periods and future plant license-extension considerations. Based on the above, in 1999, the United States Nuclear Regulatory Commission initiated a comprehensive project, with the nuclear industry as a participant, to revisit the technical bases for the current regulations on PTS. This paper provides an overview and status of the methodology that has evolved over the last two years through interactions between experts in relevant disciplines (TH, PRA, materials and fracture mechanics, and non-destructive and destructive examination to predict distribution of fabrication induced flaws in the belt-line region of the PWR vessels) from the NRC staff, their contractors, and representatives from the nuclear industry. This updated methodology is currently being implemented into the FAVOR (Fracture Analysis of Vessels: Oak Ridge) computer code for application to re-examine the adequacy of the current regulations and to determine if technical basis can be established for relaxing the current regulation. It is anticipated that the effort will be completed in 2002. (authors)

  4. Re-evaluation of the technical basis for the regulation of pressurized thermal shock in U.S. pressurized water reactor vessels

    International Nuclear Information System (INIS)

    Malik, S.N.; Kirk, M.T.; Jackson, D.A.; Hackett, E.M.; Chokshi, N.C.; Siu, N.O.; Woods, H.W.; Bessette, D.E.; Dickson, T.L.

    2001-01-01

    The current federal regulation to insure that pressurized-water nuclear reactor pressure vessels (RPVs) maintain their structural integrity when subjected to potential pressurized thermal shock (PTS) events during the life of the plant were derived from computational models and technologies that were developed in the early-to-mid 1980's. Since that time, there have been several advancements and refinements to the relevant fracture technology, materials characterization methods, probabilistic risk assessment (PRA) and thermal-hydraulics (TH) computational methods. Preliminary studies performed in 1998 (that applied this new technology) indicated the potential that technical bases can be established to support a relaxation of the current federal regulation (10 CFR 50.61) for PTS. A revision of PTS regulation could have significant implications for plants reaching their end-of-license periods and future plant license-extension considerations. Based on the above, in 1999, the United States Nuclear Regulatory Commission initiated a comprehensive project, with the nuclear industry as a participant, to revisit the technical bases for the current regulations on PTS. This paper provides an overview and status of the methodology that has evolved over the last two years through interactions between experts in relevant disciplines (TH, PRA, materials and fracture mechanics, and non-destructive and destructive examination to predict distribution of fabrication induced flaws in the belt-line region of the PWR vessels) from the NRC staff, their contractors, and representatives from the nuclear industry. This updated methodology is currently being implemented into the FAVOR (Fracture Analysis of Vessels: Oak Ridge) computer code for application to re-examine the adequacy of the current regulations and to determine if technical basis can be established for relaxing the current regulation. It is anticipated that the effort will be completed in 2002. (authors)

  5. High-Pressure Shock Compression of Solids VIII The Science and Technology of High-Velocity Impact

    CERN Document Server

    Chhabildas, Lalit C; Horie, Yasuyuki

    2005-01-01

    Research in the field of shock physics and ballistic impact has always been intimately tied to progress in development of facilities for accelerating projectiles to high velocity and instrumentation for recording impact phenomena. The chapters of this book, written by leading US and European experts, cover a broad range of topics and address researchers concerned with questions of material behaviour under impulsive loading and the equations of state of matter, as well as the design of suitable instrumentation such as gas guns and high-speed diagnostics. Applications include high-speed impact dynamics, the inner composition of planets, syntheses of new materials and materials processing. Among the more technologically-oriented applications treated is the testing of the flight characteristics of aeroballistic models and the assessment of impacts in the aerospace industry.

  6. Measurements and correlations of turbulent burning velocities over wide ranges of fuels and elevated pressures

    KAUST Repository

    Bradley, Derek; Lawes, Malcolm; Liu, Kexin; Mansour, Morkous S.

    2013-01-01

    The implosion technique has been used to extend measurements of turbulent burning velocities over greater ranges of fuels and pressures. Measurements have been made up to 3.5 MPa and at strain rate Markstein numbers as low as 23. The implosion technique, with spark ignition at two opposite wall positions within a fan-stirred spherical bomb is capable of measuring turbulent burning velocities, at higher pressures than is possible with central ignition. Pressure records and schlieren high speed photography define the rate of burning and the smoothed area of the flame front. The first aim of the study was to extend the previous measurements with ethanol and propane-air, with further measurements over wider ranges of fuels and equivalence ratios with mixtures of hydrogen, methane, 10% hydrogen-90% methane, toluene, and i-octane, with air. The second aim was to study further the low turbulence regime in which turbulent burning co-exists with laminar flame instabilities. Correlations are presented of turbulent burning velocity normalised by the effective rms turbulent velocity acting on the flame front, ut=u0k , with the Karlovitz stretch factor, K, for different strain rate Markstein numbers, a decrease in which increases ut=u0k . Experimental correlations are presented for the present measurements, combined with previous ones. Different burning regimes are also identified, extending from that of mixed turbulence/laminar instability at low values of K to that at high values of K, in which ut=u0k is gradually reduced due to increasing localised flame extinctions. © 2012 The Combustion Institute.

  7. Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-3 and TSE-4 and update of TSE-1 and TSE-2 analysis

    International Nuclear Information System (INIS)

    Cheverton, R.D.; Bolt, S.E.

    1977-01-01

    The LOCA-ECC Thermal Shock Program was established to investigate the potential for flaw propagation in pressurized-water reactor (PWR) vessels during injection of emergency core coolant following a loss-of-coolant accident. Studies thus far have included fracture mechanics analyses of typical PWRs, the design and construction of a thermal shock test facility, determination of material properties for test specimens, and four thermal shock experiments with 0.53-m-OD (21-in.) by 0.15-m-wall (6-in.) cylindrical test specimens. In the first experiment, initiation was not expected and did not occur, although there was a small amount of subcritical crack growth. In the second experiment, initiation of a semicircular flaw took place as expected; the final length along the surface was about four times the initial length, but there was no radial growth. The third and fourth experiments were similar, and the long axial flaw initiated in good agreement with predictions

  8. Pressurized thermal shock re-evaluation studies for Korean PWR plant

    International Nuclear Information System (INIS)

    Jung, Sung Gyu; Kim, Hyun Su; Jin, Tae Eun; Jang, Chang Hee

    2001-01-01

    The PTS reference temperature of reactor pressure vessel for one of the Korean NPPs has been predicted to exceed the screening criteria before it reaches it's design life. To cope with this issue, a plant-specific PTS analysis had been performed in accordance with the Regulatory Guide 1.154 in 1999. As a result of that analysis, it was found that current methodology of RG. 1.154 was very conservative. The objective of this study is to examine the effects of changing various input parameters and to determine the amount of conservatism of the current PTS analysis method. To do this, based on the past PTS analysis experience, parametric study were performed for various models using modified VISA-II code. This paper discusses the analysis results and recommendations to reduce the conservatism of current analysis method

  9. Assessment of selected TRAC and RELAP5 calculations for Oconee-1 pressurized thermal shock study

    International Nuclear Information System (INIS)

    Rohatgi, U.S.; Pu, J.; Saha, P.; Jo, J.

    1984-11-01

    Several Oconee-1 overcooling transients that were computed by LANL and INEL using the latest versions of TRAC-PF1 and RELAPS/MOD1.5 codes have been reviewed by BNL. Three of these transients were selected for detailed review as they either had the potential of challenging the integrity of the pressure vessel or highlighted the effect of code differences. These are: (1) Main Steam Line Break (MSLB); (2) All Turbine Bypass Valves Stuck Open; and (3) 2-Inch Small Break LOCA. Both codes were reasonably successful in modeling these transients. However, there were differences in the code results even though the specified scenarios were exactly the same for two transients (MSLB and Small Break LOCA). This report compares the code results and explains the possible reasons for these differences. Recommendations have been made regarding which result seems more reasonable for a specific transient

  10. Controlling Bottom Hole Flowing Pressure Within a Specific Range for Efficient Coalbed Methane Drainage

    Science.gov (United States)

    Zhao, Bin; Wang, Zhi-Yin; Hu, Ai-Mei; Zhai, Yu-Yang

    2013-11-01

    The stress state of coal surrounding a coalbed methane (CBM) production well is affected by the bottom hole flowing pressure (BHFP). The permeability of coal shows a marked change under compression. The BHFP must be restricted to a specific range to favor higher permeability in the surrounding coal and thus higher productivity of the well. A new method to determine this specific range is proposed in this paper. Coal has a rather low tensile strength, which induces tensile failure and rock disintegration. The deformation of coal samples under compression has four main stages: compaction, elastic deformation, strain hardening, and strain softening. Permeability is optimal when the coal samples are in the strain softening stage. The three critical values of BHFP, namely, p wmin, p wmid, and p wupper, which correspond to the occurrence of tensile failure, the start of strain softening, and the beginning of plastic deformation, respectively, are derived from theoretical principles. The permeability of coal is in an optimal state when the BHFP is between p wmin and p wmid. The BHFP should be confined to this specific range for the efficient drainage of CBM wells. This method was applied to field operations in three wells in the Hancheng CBM field in China. A comprehensive analysis of drainage data and of the BHFP indicates that the new method is effective and offers significant improvement to current practices.

  11. Solubility of hydrogen in water in a broad temperature and pressure range

    International Nuclear Information System (INIS)

    Baranenko, V.I.; Kirov, V.S.

    1989-01-01

    In the coolant of water-water reactors, as a result of radiolytic decomposition of water and chemical additives (hydrazine and ammonia) and saturation of the make-up water of the first loop with free hydrogen in order to suppress radiolysis, 30-60 ml/kg of hydrogen is present in normal conditions. On being released from the water, it is free to accumulate in micropores of the metals, resulting in hydrogen embrittlement; gas accumulates in stagnant zones, with deterioration in heat transfer in the first loop and corresponding difficulty in the use of the reactor and the whole reactor loop. To determine the amount of free hydrogen and hydrogen dissolved in water in different elements of the first loop, it is necessary to know the limiting solubility of hydrogen in water at different temperatures and pressures, and also to have the corresponding theoretical dependences. The experimental data on the solubility of hydrogen in water are nonsystematic and do not cover the parameter ranges of modern nuclear power plants (P = 10-30 MPa, T = 260-370C). Therefore, the aim of the present work is to establish a well-founded method of calculating the limiting solubility of hydrogen in water and, on this basis, to compile tables of the limiting solubility of hydrogen in water at pressures 0.1-50 MPa and temperatures 0-370C

  12. Knee arthritis pain is reduced and range of motion is increased following moderate pressure massage therapy.

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Gonzalez, Gladys; Funk, C G

    2015-11-01

    The literature on massage therapy effects on knee pain suggests that pain was reduced based on self-report, but little is known about range of motion (ROM) effects. Medical School staff and faculty who had knee arthritis pain were randomly assigned to a moderate pressure massage therapy or a waitlist control group (24 per group). Self-reports included the WOMAC (pain, stiffness and function) and the Pittsburgh Sleep Quality Index. ROM and ROM-related pain were assessed before and after the last sessions. The massage group showed an immediate post-massage increase in ROM and a decrease in ROM-associated pain. On the last versus the first day of the study, the massage group showed greater increases in ROM and decreases in ROM-related pain as well as less self-reported pain and sleep disturbances than the waitlist control group. These data highlight the effectiveness of moderate pressure massage therapy for increasing ROM and lessening ROM-related pain and long-term pain and sleep disturbances. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Theory of mass-discrimination effects in ion extraction from a plasma of wide pressure range

    International Nuclear Information System (INIS)

    Chang, J.-S.; Kodera, K.

    1979-01-01

    Mass-discrimination effects in stagnation-point ion extraction are treated for a plasma with a wide range of Knudsen number, i.e. when the charged particle's mean free path 3 , ion Schmidt numbers, from 0 to 10 4 , the effective Knudsen number K from 0 to infinity, and the Debye ratio Rsub(p)/lambdasub(D) from 0 to 10 -1 . Numerical results show that: (1) for a non-flowing plasma, mass-discrimination effects increase with increasing effective Knudsen number (or gas pressure) and decreasing sampling potential; (2) for a non-flowing plasma, no significant effect of the Debye ratio on mass-discrimination was found; (3) for a flowing plasma, mass-discrimination effects decrease with increasing Reynolds number (or flow velocity) and ion Schmidt number, and with decreasing sampling potential and effective Knudsen number. (Auth.)

  14. Surface treatment by the ion flow from electron beam generated plasma in the forevacuum pressure range

    Directory of Open Access Journals (Sweden)

    Klimov Aleksandr

    2018-01-01

    Full Text Available The paper presents research results of peculiarities of gas ion flows usage and their generation from large plasma formation (>50 sq.cm obtained by electron beam ionization of gas in the forevacuum pressure range. An upgraded source was used for electron beam generation, which allowed obtaining ribbon electron beam with no transmitting magnetic field. Absence of magnetic field in the area of ion flow formation enables to obtain directed ion flows without distorting their trajectories. In this case, independent control of current and ion energy is possible. The influence of electron beam parameters on the parameters of beam plasma and ion flow – current energy and density – was determined. The results of alumina ceramics treatment with a beam plasma ions flow are given.

  15. Raman spectroscopic characterization of CH4 density over a wide range of temperature and pressure

    Science.gov (United States)

    Shang, Linbo; Chou, I-Ming; Burruss, Robert; Hu, Ruizhong; Bi, Xianwu

    2014-01-01

    The positions of the CH4 Raman ν1 symmetric stretching bands were measured in a wide range of temperature (from −180 °C to 350 °C) and density (up to 0.45 g/cm3) using high-pressure optical cell and fused silica capillary capsule. The results show that the Raman band shift is a function of both methane density and temperature; the band shifts to lower wavenumbers as the density increases and the temperature decreases. An equation representing the observed relationship among the CH4 ν1 band position, temperature, and density can be used to calculate the density in natural or synthetic CH4-bearing inclusions.

  16. Effect of Initiation Time of Hydrostatic Pressure Shock on Chromosome Set Doubling of Tetraploidization in Turbot Scophthalmus maximus.

    Science.gov (United States)

    Zhu, Xiangping; Lin, Zhengmei; Wu, Zhihao; Li, Jiandong; You, Feng

    2017-10-01

    The objective of the study was to clarify the effects of initiation time on chromosome set doubling induced by hydrostatic pressure shock through nuclear phase fluorescent microscopy in turbot Scophthalmus maximus. The ratio of developmentally delayed embryo and chromosome counting was used to assess induction efficiency. For the embryos subjected to a pressure of 67.5 MPa for 6 min at prometaphase (A group), chromosomes recovered to the pre-treatment condition after 11-min recovering. The first nuclear division and cytokinesis proceeded normally. During the second cell cycle, chromosomes did not enter into metaphase after prometaphase, but spread around for about 13 min, then assembled together and formed a large nucleus without anaphase separation; the second nuclear division and cytokinesis was inhibited. The ratio of developmentally delayed embryo showed that the second mitosis of 78% A group embryo was inhibited. The result of chromosome counting showed that the tetraploidization rate of A group was 72%. For the embryos subjected to a pressure of 67.5 MPa for 6 min at anaphase (B group), chromosomes recovered to the pre-treatment condition after about 31-min recovering. Afterwards, one telophase nucleus formed without anaphase separation; the first nuclear division was inhibited. The time of the first cleavage furrow occurrence of B group embryos delayed 27 min compared with that of A group embryos. With the first cytokinesis proceeding normally, 81.3% B group embryos were at two-cell stage around the middle of the second cell cycle after treatment. Those embryos were one of the two blastomeres containing DNA and the other without DNA. The first nuclear division of those embryos was inhibited. During the third cell cycle after treatment, 65.2% of those abovementioned embryos were at four-cell stage, cytokinesis occurred in both blastomeres, and nuclear division only occurred in the blastomere containing DNA. Of those abovementioned embryos, 14.0% were at

  17. Density Measurements of Waste Cooking Oil Biodiesel and Diesel Blends Over Extended Pressure and Temperature Ranges

    Directory of Open Access Journals (Sweden)

    Thanh Xuan NguyenThi

    2018-05-01

    Full Text Available Density and compressibility are primordial parameters for the optimization of diesel engine operation. With this objective, these properties were reported for waste cooking oil biodiesel and its blends (5% and 10% by volume mixed with diesel. The density measurements were performed over expanded ranges of pressure (0.1 to 140 MPa and temperature (293.15 to 353.15 K compatible with engine applications. The isothermal compressibility was estimated within the same experimental range by density differentiation. The Fatty Acid Methyl Esters (FAMEs profile of the biodiesel was determined using a Gas Chromatography–Mass Spectrometry (GC-MS technique. The storage stability of the biodiesel was assessed in terms of the reproducibility of the measured properties. The transferability of this biodiesel fuel was discussed on the basis of the standards specifications that support their use in fuel engines. Additionally, this original set of data represents meaningful information to develop new approaches or to evaluate the predictive capability of models previously developed.

  18. Circadian rhythms in blood pressure in free-ranging three-toed sloths (Bradypus variegatus

    Directory of Open Access Journals (Sweden)

    Duarte D.P.F.

    2003-01-01

    Full Text Available Blood pressure (BP profiles were monitored in nine free-ranging sloths (Bradypus variegatus by coupling one common carotid artery to a BP telemetry transmitter. Animals moved freely in an isolated and temperature-controlled room (24ºC with 12/12-h artificial light-dark cycles and behaviors were observed during resting, eating and moving. Systolic (SBP and diastolic (DBP blood pressures were sampled for 1 min every 15 min for 24 h. BP rhythm over 24 h was analyzed by the cosinor method and the mesor, amplitude, acrophase and percent rhythm were calculated. A total of 764 measurements were made in the light cycle and 721 in the dark cycle. Twenty-four-hour values (mean ± SD were obtained for SBP (121 ± 22 mmHg, DBP (86 ± 17 mmHg, mean BP (MBP, 98 ± 18 mmHg and heart rate (73 ± 16 bpm. The SBP, DBP and MBP were significantly higher (unpaired Student t-test during the light period (125 ± 21, 88 ± 15 and 100 ± 17 mmHg, respectively than during the dark period (120 ± 21, 85 ± 17 and 97 ± 17 mmHg, respectively and the acrophase occurred between 16:00 and 17:45 h. This circadian variation is similar to that observed in cats, dogs and marmosets. The BP decreased during "behavioral sleep" (MBP down from 110 ± 19 to 90 ± 19 mmHg at 21:00 to 8:00 h. Both feeding and moving induced an increase in MBP (96 ± 17 to 119 ± 17 mmHg at 17:00 h and 97 ± 19 to 105 ± 12 mmHg at 15:00 h, respectively. The results show that conscious sloths present biphasic circadian fluctuations in BP levels, which are higher during the light period and are mainly synchronized with feeding.

  19. 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)

  20. Formation and decay of laser-generated shock waves

    Energy Technology Data Exchange (ETDEWEB)

    Cottet, F.; Romain, J.P.

    1982-01-01

    The process of formation and decay of laser-generated shock waves is described by a hydrodynamic model. Measurements of shock velocities are performed on copper foils for incident intensities between 3 x 10/sup 11/ and 3 x 10/sup 12/ W/cm/sup 2/, with the use of piezoelectric detectors. Maximum induced pressures are found between 0.5 and 1.2 Mbar in the intensity range considered. Analysis of the results with the shock-evolution model outlines the importance of the decay process of laser-generated shocks.

  1. Phase transition in a shock loaded 304 stainless steel

    International Nuclear Information System (INIS)

    Naulin, G.

    1989-11-01

    Systematic shock recovery experiments have been performed on a Z2 CN 18-10 stainless steel (304 AISI), shocked in a pressure range of 5-13 GPa. The pulse durations lay between 0.1 μs and 2 μs. The phases transformation γ (fcc) to α' (bcc) is studied. The evolution of microstructures, the nucleation and the coalescence of α' phase embryos have been observed by TEM examinations. Quantitative measurements of the α' phase allow to plot diagrams of transformed phase versus shock pressure and pulse duration. Manganin gages allow to know the pressure evolution during the impact. The Olson and Cohen model describes the development of the α' phase versus the plastic deformation. An adaptation of this model has been developed, which describes the development of the α' phase versus shock pressure and pulse duration. Theoretical laws give a good correlation with experimental results [fr

  2. Studies on hyperbaric WIG welding in the pressure range between 1 and 16 bar

    International Nuclear Information System (INIS)

    Huismann, G.

    1985-01-01

    Within the framework of this paper the following individual investigations were carried out for the application of the TIG process under hyperbar conditions (underwater welding): 1. Influence of the pressure on the formation and efficiency of the inert gas shield. 2. Influence of the materials and point geometry of the tungsten electrode on the erosion of those and the effect thereof on the welding process under increased pressure. 3. Influence of the pressure on the welding material geometry in blind-welding without welding material as well as built-in welding and root welding. 4. Influence of the pressure on the gas-metal reactions. The changes of the electric, mechanical and geometrical properties and characteristics of the electric arc by increased pressure are the fundamentals for understanding the resulting influences of the pressure on the properties of welded joints. (orig./MM) [de

  3. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    Science.gov (United States)

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  4. 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

  5. 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

  6. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. Part 1: Pressure distribution. Part 2: Wall shear stress. Part 3: Simplified formulas for the prediction of surface pressures and skin friction

    Science.gov (United States)

    Adamson, T. C., Jr.; Liou, M. S.; Messiter, A. F.

    1980-01-01

    An asymptotic description is derived for the interaction between a shock wave and a turbulent boundary layer in transonic flow, for a particular limiting case. The dimensionless difference between the external flow velocity and critical sound speed is taken to be much smaller than one, but large in comparison with the dimensionless friction velocity. The basic results are derived for a flat plate, and corrections for longitudinal wall curvature and for flow in a circular pipe are also shown. Solutions are given for the wall pressure distribution and the shape of the shock wave. Solutions for the wall shear stress are obtained, and a criterion for incipient separation is derived. Simplified solutions for both the wall pressure and skin friction distributions in the interaction region are given. These results are presented in a form suitable for use in computer programs.

  7. Development and implementation of a pressure propagation code applicable in spherical geometry to euler/isentropic/acoustic modelling. Comparative treatment of shock-up and refection on simplified rigid or elastic obstacles

    International Nuclear Information System (INIS)

    Essers, J.A.

    1987-01-01

    A sophisticated computer code for the calculation of plane or spherical pressure waves and their reflection on a simplified rigid or flexible obstacle has been constructed. Different options: choice of explicit or implicit scheme, use of eulerian, isentropic or acoustic flow models, introduction of different artificial viscosities, use of uniform or non-uniform adaptive grids have been made available and validated by simple shock waves computations. The results from different numerical experiments are presented. They have been used to evaluate the values of artificial viscosity coefficients leading to acceptable pressure pulses. In particular, the following important conclusions have been confirmed: - the linear acoustic model leads to important errors except for extremely weak overpressures; - an excellent accuracy can be obtained with the non-linear isentropic model in a wide overpressure range; - as opposed to the eulerian and to the non-linear isentropic models, the acoustic model is completely uncapable of predicting the shock-up phenomenon, and can therefore lead to important errors in the prediction of the pulse shape even for very weak overpressures

  8. Photon Pressure Force on Space Debris TOPEX/Poseidon Measured by Satellite Laser Ranging

    Science.gov (United States)

    Kucharski, D.; Kirchner, G.; Bennett, J. C.; Lachut, M.; Sośnica, K.; Koshkin, N.; Shakun, L.; Koidl, F.; Steindorfer, M.; Wang, P.; Fan, C.; Han, X.; Grunwaldt, L.; Wilkinson, M.; Rodríguez, J.; Bianco, G.; Vespe, F.; Catalán, M.; Salmins, K.; del Pino, J. R.; Lim, H.-C.; Park, E.; Moore, C.; Lejba, P.; Suchodolski, T.

    2017-10-01

    The (TOPography EXperiment) TOPEX/Poseidon (T/P) altimetry mission operated for 13 years before the satellite was decommissioned in January 2006, becoming a large space debris object at an altitude of 1,340 km. Since the end of the mission, the interaction of T/P with the space environment has driven the satellite's spin dynamics. Satellite laser ranging (SLR) measurements collected from June 2014 to October 2016 allow for the satellite spin axis orientation to be determined with an accuracy of 1.7°. The spin axis coincides with the platform yaw axis (formerly pointing in the nadir direction) about which the body rotates in a counterclockwise direction. The combined photometric and SLR data collected over the 11 year time span indicates that T/P has continuously gained rotational energy at an average rate of 2.87 J/d and spins with a period of 10.73 s as of 19 October 2016. The satellite attitude model shows a variation of the cross-sectional area in the Sun direction between 8.2 m2 and 34 m2. The direct solar radiation pressure is the main factor responsible for the spin-up of the body, and the exerted photon force varies from 65 μN to 228 μN around the mean value of 138.6 μN. Including realistic surface force modeling in orbit propagation algorithms will improve the prediction accuracy, giving better conjunction warnings for scenarios like the recent close approach reported by the ILRS Space Debris Study Group—an approximate 400 m flyby between T/P and Jason-2 on 20 June 2017.

  9. Complete equation of state for shocked liquid nitrogen: Analytical developments

    International Nuclear Information System (INIS)

    Winey, J. M.; Gupta, Y. M.

    2016-01-01

    The thermodynamic response of liquid nitrogen has been studied extensively, in part, due to the long-standing interest in the high pressure and high temperature dissociation of shocked molecular nitrogen. Previous equation of state (EOS) developments regarding shocked liquid nitrogen have focused mainly on the use of intermolecular pair potentials in atomistic calculations. Here, we present EOS developments for liquid nitrogen, incorporating analytical models, for use in continuum calculations of the shock compression response. The analytical models, together with available Hugoniot data, were used to extrapolate a low pressure reference EOS for molecular nitrogen [Span, et al., J. Phys. Chem. Ref. Data 29, 1361 (2000)] to high pressures and high temperatures. Using the EOS presented here, the calculated pressures and temperatures for single shock, double shock, and multiple shock compression of liquid nitrogen provide a good match to the measured results over a broad range of P-T space. Our calculations provide the first comparison of EOS developments with recently-measured P-T states under multiple shock compression. The present EOS developments are general and are expected to be useful for other liquids that have low pressure reference EOS information available.

  10. Supplementary vapor pressure data of the glycol ethers, 1-methoxy-2-propanol, and 2-methoxyethanol at a pressure range of (15 to 177) kPa

    International Nuclear Information System (INIS)

    Bejarano, Arturo; Poveda, Laura J.; Fuente, Juan C. de la

    2012-01-01

    Highlights: ► Vapor pressure of 2-methoxyethanol and 1-methoxy-2-propanol were measured. ► Complementary data are reported at ranges of (342 to 417) K and (15 to 177) kPa. ► Three commonly used vapor pressure equations were fitted to experimental data. ► The parameters of Antoine and Wagner type equations were estimated. ► The relative deviations (rmsd) from the three vapor pressure equations were <0.4%. - Abstract: The vapor pressure of pure 1-methoxy-2-propanol and 2-methoxyethanol, commonly used as co-solvents in inks, paints, coatings, organic/water solutions among many other applications, were measured with a dynamic recirculation apparatus at a pressure range of (15 to 177) kPa. The measurements were performed at temperature ranges of (342 to 412) K for 1-methoxy-2-propanol and (346 to 417) K for 2-methoxyethanol. The maximum likelihood method was used to estimate the parameters of the Antoine equation, the parameters of an extended Antoine equation and the Wagner equation were determined by non linear least squares method. The three models showed root mean square deviations (rmsd) of 0.39%, 0.38%, and 0.29%, and 0.37%, 0.33%, and 0.32%, for 1-methoxy-2-propanol and 2-methoxyethanol, respectively. Additionally, the experimental data and correlation were compared with those available in the literature.

  11. High Pressure In Situ X-ray Diffraction Study of MnO to 120 GPa and Comparison with Shock Compression Experiment

    Science.gov (United States)

    Yagi, Takehiko; Kondo, Tadashi; Syono, Yasuhiko

    1997-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment (Syono et al., this symposium), high pressure in situ x-ray experiments were carried out up to 120 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil and x-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase into hexagonal unit cell was observed from 25-40 GPa, which continues to increase up to 90 GPa. At around 90 GPa, discontinuous change of the diffraction was observed. This new phase cannot be explained by a simple B2 structure and the analysis of this phase is in progress. This high pressure phase has metallic appearance, which reverses to transparent MnO on release of pressure.

  12. Complementary vapor pressure data for 2-methyl-1-propanol and 3-methyl-1-butanol at a pressure range of (15 to 177) kPa

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Arturo; Quezada, Nathalie [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Fuente, Juan C. de la [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile)], E-mail: juan.delafuente@usm.cl

    2009-09-15

    The vapor pressure of pure 2-methyl-1-propanol and 3-methyl-1-butanol, components called congeners that are present in aroma of wine, pisco, and other alcoholic beverages, were measured with a dynamic recirculation apparatus at a pressure range of (15 to 177) kPa with an estimated uncertainty <0.2%. The measurements were performed at temperature ranges of (337 to 392) K for 2-methyl-1-propanol and (358 to 422) K for 3-methyl-1-butanol. Data were correlated using a Wagner-type equation with standard deviations of 0.09 kPa for the vapor pressure of 2-methyl-1-propanol and 0.21 kPa for 3-methyl-1-butanol. The experimental data and correlation were compared with data selected from the literature.

  13. 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

  14. Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia.

    Science.gov (United States)

    Tünsmeyer, Julia; Hopster, Klaus; Feige, Karsten; Kästner, Sabine Br

    2015-05-01

    To determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia. Experimental study. Seven healthy warmblood horses, aged 3-11 years, weighing 470-565 kg. Measurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg(-1) minute(-1)) over ten minutes followed by norepinephrine (0.1 mg kg(-1) IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg(-1) IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHgstandard deviation for SAP, MAP and DAP were 0.1 ± 19.4 mmHg, 0.5 ± 14.0, 4.7 ± 15.6, respectively. At high pressure levels bias and SD were 26.1 ± 37.3 (SAP), 4.2 ± 19.4 (MAP), 1.5 ± 16.8 (DAP) and at low pressures -20.0 ± 20.9 (SAP), -11.4 ± 19.6 (MAP), -4.7 ± 20.1 (DAP), with HDO measurements at a MAP <50 mmHg often failing. Good agreement with invasive arterial blood pressures was obtained with HDO at normotensive levels in horses. At high and low pressure ranges HDO was unreliable. Therefore, if haemodynamic instability is expected, invasive measurement remains preferable. © 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  15. Micromechanism Underlying Nonlinear Stress-Dependent K0 of Clays at a Wide Range of Pressures

    Directory of Open Access Journals (Sweden)

    Xiang-yu Shang

    2015-01-01

    Full Text Available In order to investigate the mechanism underlying the reported nonlinear at-rest coefficient of earth pressure, K0 of clays at high pressure, a particle-scale model which can be used to calculate vertical and horizontal repulsion between clay particles has been proposed. This model has two initial states which represent the clays at low pressure and high pressure, and the particles in this model can undergo rotation and vertical translation. The computation shows that the majority of particles in a clay sample at high pressure state would experience rotation during one-dimensional compression. In addition, rotation of particles which tends to form a parallel structure causes an increase of the horizontal interparticle force, while vertical translation leads to a decrease in it. Finally, the link between interparticle force, microstructure, and macroscopic K0 is analyzed and it can be used to interpret well the nonlinear changes in K0 with both vertical consolidation stress and height-diameter ratio.

  16. 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."

  17. Increases of heat shock proteins and their mRNAs at high hydrostatic pressure in a deep-sea piezophilic bacterium, Shewanella violacea.

    Science.gov (United States)

    Sato, Hiroshi; Nakasone, Kaoru; Yoshida, Takao; Kato, Chiaki; Maruyama, Tadashi

    2015-07-01

    When non-extremophiles encounter extreme environmental conditions, which are natural for the extremophiles, stress reactions, e.g., expression of heat shock proteins (HSPs), are thought to be induced for survival. To understand how the extremophiles live in such extreme environments, we studied the effects of high hydrostatic pressure on cellular contents of HSPs and their mRNAs during growth in a piezophilic bacterium, Shewanella violacea. HSPs increased at high hydrostatic pressures even when optimal for growth. The mRNAs and proteins of these HSPs significantly increased at higher hydrostatic pressure in S. violacea. In the non-piezophilic Escherichia coli, however, their mRNAs decreased, while their proteins did not change. Several transcriptional start sites (TSSs) for HSP genes were determined by the primer extension method and some of them showed hydrostatic pressure-dependent increase of the mRNAs. A major refolding target of one of the HSPs, chaperonin, at high hydrostatic pressure was shown to be RplB, a subunit of the 50S ribosome. These results suggested that in S. violacea, HSPs play essential roles, e.g., maintaining protein complex machinery including ribosomes, in the growth and viability at high hydrostatic pressure, and that, in their expression, the transcription is under the control of σ(32).

  18. Combining central venous-to-arterial partial pressure of carbon dioxide difference and central venous oxygen saturation to guide resuscitation in septic shock.

    Science.gov (United States)

    Du, Wei; Liu, Da-Wei; Wang, Xiao-Ting; Long, Yun; Chai, Wen-Zhao; Zhou, Xiang; Rui, Xi

    2013-12-01

    Central venous oxygen saturation (Scvo2) is a useful therapeutic target when treating septic shock. We hypothesized that combining Scvo2 and central venous-to-arterial partial pressure of carbon dioxide difference (△Pco2) may provide additional information about survival. We performed a retrospective analysis of 172 patients treated for septic shock. All patients were treated using goal-directed therapy to achieve Scvo2 ≥ 70%. After 6 hours of treatment, we divided patients into 4 groups based on Scvo2 (<70% or ≥ 70%) and △Pco2 (<6 mm Hg or ≥ 6 mm Hg). Overall, 28-day mortality was 35.5%. For patients in whom the Scvo2 target was not achieved at 6 hours, mortality was 50.0%, compared with 29.5% in those in whom Scvo2 exceeded 70% (P = .009). In patients with Scvo2 ≥ 70%, mortality was lower if △Pco2 was <6 mm Hg than if △Pco2 was ≥ 6 mm Hg (56.1% vs 16.1%, respectively; P < .001) and 6-hour lactate clearance was superior (0.01 ± 0.61 vs 0.21 ± 0.31, respectively; P = .016). The combination of Scvo2 and △Pco2 appears to predict outcome in critically ill patients resuscitated from septic shock better than Scvo2 alone. Patients who meet both targets appear to clear lactate more efficiently. © 2013.

  19. Experimental analysis of shock wave effects in copper

    International Nuclear Information System (INIS)

    Llorca, Fabrice; Buy, Francois; Farre, Jose

    2002-01-01

    This paper proposes the analysis of shock wave effects for a high purity copper. The method developed is based on the analysis of the mechanical behavior of as received and shocked materials. Shock effect is generated through plates impact tests performed in the range 9 GPa to 12 GPa on a single stage light gas gun. Therefore, as-received and impacted materials are characterized on quasi static and Split Hopkinson apparatus. The difference between measured stresses between as received and shocked materials allows to understand shock effects in the low pressure range of study. A specific modeling approach is engaged in order to give indications about the evolution of the microstructure of the materials

  20. Shock tube measurements of the branching ratios of propene + OH -> products

    KAUST Repository

    Khaled, Fathi; Badra, Jihad Ahmad; Giri, Binod; Farooq, Aamir

    2014-01-01

    in a shock tube behind reflected shock conditions over the temperature range of 812 K – 1460 K and pressures near 1 atm. The reaction progress was followed by monitoring OH radical near 306.7 nm using UV laser absorption. The first experimental

  1. Bifurcation parameters of a reflected shock wave in cylindrical channels of different roughnesses

    Science.gov (United States)

    Penyazkov, O.; Skilandz, A.

    2018-03-01

    To investigate the effect of bifurcation on the induction time in cylindrical shock tubes used for chemical kinetic experiments, one should know the parameters of the bifurcation structure of a reflected shock wave. The dynamics and parameters of the shock wave bifurcation, which are caused by reflected shock wave-boundary layer interactions, are studied experimentally in argon, in air, and in a hydrogen-nitrogen mixture for Mach numbers M = 1.3-3.5 in a 76-mm-diameter shock tube without any ramp. Measurements were taken at a constant gas density behind the reflected shock wave. Over a wide range of experimental conditions, we studied the axial projection of the oblique shock wave and the pressure distribution in the vicinity of the triple Mach configuration at 50, 150, and 250 mm from the endwall, using side-wall schlieren and pressure measurements. Experiments on a polished shock tube and a shock tube with a surface roughness of 20 {μ }m Ra were carried out. The surface roughness was used for initiating small-scale turbulence in the boundary layer behind the incident shock wave. The effect of small-scale turbulence on the homogenization of the transition zone from the laminar to turbulent boundary layer along the shock tube perimeter was assessed, assuming its influence on a subsequent stabilization of the bifurcation structure size versus incident shock wave Mach number, as well as local flow parameters behind the reflected shock wave. The influence of surface roughness on the bifurcation development and pressure fluctuations near the wall, as well as on the Mach number, at which the bifurcation first develops, was analyzed. It was found that even small additional surface roughness can lead to an overshoot in pressure growth by a factor of two, but it can stabilize the bifurcation structure along the shock tube perimeter.

  2. Burnout correlations for even- and odd-numbered peripheral rod clusters over low pressure range

    International Nuclear Information System (INIS)

    Akaho, E.H.K.

    1995-01-01

    Burnout data with low pressure Freon-113 for even- and odd- numbered peripheral rod clusters with relatively large spacings were used to derive equations in terms of dimensionless parameters suggested by Barnett. The equations which are for three different flow regimes for each rod geometry (even or odd) were found to predict burnout data with maximum RMS deviation being 3.8%. (author). 11 figs., 3 tabs., 15 refs

  3. Precise predictions of H2O line shapes over a wide pressure range using simulations corrected by a single measurement

    Science.gov (United States)

    Ngo, N. H.; Nguyen, H. T.; Tran, H.

    2018-03-01

    In this work, we show that precise predictions of the shapes of H2O rovibrational lines broadened by N2, over a wide pressure range, can be made using simulations corrected by a single measurement. For that, we use the partially-correlated speed-dependent Keilson-Storer (pcsdKS) model whose parameters are deduced from molecular dynamics simulations and semi-classical calculations. This model takes into account the collision-induced velocity-changes effects, the speed dependences of the collisional line width and shift as well as the correlation between velocity and internal-state changes. For each considered transition, the model is corrected by using a parameter deduced from its broadening coefficient measured for a single pressure. The corrected-pcsdKS model is then used to simulate spectra for a wide pressure range. Direct comparisons of the corrected-pcsdKS calculated and measured spectra of 5 rovibrational lines of H2O for various pressures, from 0.1 to 1.2 atm, show very good agreements. Their maximum differences are in most cases well below 1%, much smaller than residuals obtained when fitting the measurements with the Voigt line shape. This shows that the present procedure can be used to predict H2O line shapes for various pressure conditions and thus the simulated spectra can be used to deduce the refined line-shape parameters to complete spectroscopic databases, in the absence of relevant experimental values.

  4. Expansion of the cathode spot and generation of shock waves in the plasma of a volume discharge in atmospheric-pressure helium

    International Nuclear Information System (INIS)

    Omarov, O. A.; Kurbanismailov, V. S.; Arslanbekov, M. A.; Gadzhiev, M. Kh.; Ragimkhanov, G. B.; Al-Shatravi, Ali J. G.

    2012-01-01

    The expansion of the cathode spot and the generation of shock waves during the formation and development of a pulsed volume discharge in atmospheric-pressure helium were studied by analyzing the emission spectra of the cathode plasma and the spatiotemporal behavior of the plasma glow. The transition of a diffuse volume discharge in a centimeter-long gap into a high-current diffuse mode when the gas pressure increased from 1 to 5 atm and the applied voltage rose from the statistical breakdown voltage to a 100% overvoltage was investigated. Analytical expressions for the radius of the cathode spot and its expansion velocity obtained in the framework of a spherically symmetric model agree satisfactorily with the experimental data.

  5. Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)

    1998-01-01

    In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

  6. Data collected by the Shock Wave Data Center

    International Nuclear Information System (INIS)

    Van Thiel, M.

    1976-01-01

    The Shock Wave Data Center of the Lawrence Livermore Lab collects and disseminates P.V.E. data obtained with shock waves. It has been in existence since 1964. An extensive number of papers reporting shock data had become available by that time. This was so in spite of the fact that the technology was developed only during the 2nd World War. Collection and partial evaluation of this data was therefore of value to facilitate its use by our laboratory and others who were involved with science and engineering in the high pressure field. The pressure range of the data collected is quite extensive and extends from 1 MPa to 1 TPa. One very important difference between shock wave compression data and those obtained with static presses must be emphasized, since it is often not fully appreciated. The pressure-volume locus of shock wave states (Hugoniot), which is obtained by passing increasingly stronger shocks into samples with the same initial state, rapidly increases in temperature as the shocks get stronger and the pressure and compression get higher. As a consequence, this Hugoniot locus must have a lower compressibility than isotherms obtained under static conditions. In fact, if porous or otherwise expanded samples are used, states at or near the critical region of metals can be obtained if the shock pressure is allowed to decrease in a controlled manner. Such pressure release measurements have so far only been utilized to a limited extent since the compression process has been of primary interest to workers in the field. As the use of this data in the energy field increases, however, such data will be needed more often. Applications are discussed that involve transient high pressure processes, practically all of which involve both compressed and expanded states

  7. Equation of state of U2Mo up-to Mbar pressure range: Ab-initio study

    Science.gov (United States)

    Mukherjee, D.; Sahoo, B. D.; Joshi, K. D.; Kaushik, T. C.

    2018-04-01

    Experimentally, U2Mo is known to exist in tetragonal structure at ambient conditions. In contrast to experimental reports, the past theoretical studies carried out in this material do not find this phase to be stable structure at zero pressure. In order to examine this discrepancy between experiment and theory, we have performed ab-initio electronic band structure calculations on this material. In our theoretical study, we have attempted to search for lowest enthalpy structure at ambient as well at high pressure up to 200 GPa, employing evolutionary structure search algorithm in conjunction with ab-inito method. Our investigations suggest that a hexagonal structure with space group symmetry P6/mmm is the lowest enthalpy structure not only at ambient pressure but also up to pressure range of ˜200 GPa. To further, substantiate the results of these static lattice calculations the elastic and lattice dynamical stability has also been analysed. The theoretical isotherm derived from these calculations has been utilized to determine the Hugoniot of this material. Various physical properties such as zero pressure equilibrium volume, bulk modulus and its pressure derivative has also been derived from theoretical isotherm.

  8. Absolute Hugoniot measurements from a spherically convergent shock using x-ray radiography

    Science.gov (United States)

    Swift, Damian C.; Kritcher, Andrea L.; Hawreliak, James A.; Lazicki, Amy; MacPhee, Andrew; Bachmann, Benjamin; Döppner, Tilo; Nilsen, Joseph; Collins, Gilbert W.; Glenzer, Siegfried; Rothman, Stephen D.; Kraus, Dominik; Falcone, Roger W.

    2018-05-01

    The canonical high pressure equation of state measurement is to induce a shock wave in the sample material and measure two mechanical properties of the shocked material or shock wave. For accurate measurements, the experiment is normally designed to generate a planar shock which is as steady as possible in space and time, and a single state is measured. A converging shock strengthens as it propagates, so a range of shock pressures is induced in a single experiment. However, equation of state measurements must then account for spatial and temporal gradients. We have used x-ray radiography of spherically converging shocks to determine states along the shock Hugoniot. The radius-time history of the shock, and thus its speed, was measured by radiographing the position of the shock front as a function of time using an x-ray streak camera. The density profile of the shock was then inferred from the x-ray transmission at each instant of time. Simultaneous measurement of the density at the shock front and the shock speed determines an absolute mechanical Hugoniot state. The density profile was reconstructed using the known, unshocked density which strongly constrains the density jump at the shock front. The radiographic configuration and streak camera behavior were treated in detail to reduce systematic errors. Measurements were performed on the Omega and National Ignition Facility lasers, using a hohlraum to induce a spatially uniform drive over the outside of a solid, spherical sample and a laser-heated thermal plasma as an x-ray source for radiography. Absolute shock Hugoniot measurements were demonstrated for carbon-containing samples of different composition and initial density, up to temperatures at which K-shell ionization reduced the opacity behind the shock. Here we present the experimental method using measurements of polystyrene as an example.

  9. Discrimination of Thermal versus Mechanical Effects of Shock on Rock Magnetic Properties of Spherically Shocked up to 10-160 GPa Basalt and Diabase

    Science.gov (United States)

    Bezaeva, N. S.; Swanson-Hysell, N.; Tikoo, S.; Badyukov, D. D.; Kars, M. A. C.; Egli, R.; Chareev, D. A.; Fairchild, L. M.

    2016-12-01

    Understanding how shock waves generated during hypervelocity impacts affect rock magnetic properties is key for interpreting the paleomagnetic records of lunar rocks, meteorites, and cratered planetary surfaces. Laboratory simulations of impacts show that ultra-high shocks may induce substantial post-shock heating of the target material. At high pressures (>10 GPa), shock heating occurs in tandem with mechanical effects, such as grain fracturing and creation of crystallographic defects and dislocations within magnetic grains. This makes it difficult to conclude whether shock-induced changes in the rock magnetic properties of target materials are primarily associated with mechanical or thermal effects. Here we present novel experimental methods to discriminate between mechanical and thermal effects of shock on magnetic properties and illustrate it with two examples of spherically shocked terrestrial basalt and diabase [1], which were shocked to pressures of 10 to >160 GPa, and investigate possible explanations for the observed shock-induced magnetic hardening (i.e., increase in remanent coercivity Bcr). The methods consist of i) conducting extra heating experiments at temperatures resembling those experienced during high-pressure shock events on untreated equivalents of shocked rocks (with further comparison of Bcr of shocked and heated samples) and ii) quantitative comparison of high-resolution first-order reversal curve (FORC) diagrams (field step: 0.5-0.7 mT) for shocked, heated and untreated specimens. Using this approach, we demonstrated that the shock-induced coercivity hardening in our samples is predominantly due to solid-state, mechanical effects of shock rather than alteration associated with shock heating. Indeed, heating-induced changes in Bcr in the post-shock temperature range were minor. Visual inspection of FORC contours (in addition to detailed analyses) reveals a stretching of the FORC distribution of shocked sample towards higher coercivities

  10. Boundary element analysis of stress due to thermal shock loading or reactor pressure vessel nozzle; Napetostna analiza pri nestacionarni termicni obremenitvi cevnega prikljucka reaktorske tlacne posode z metodo robnih elementov

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, J; Potrc, I [Tehniska fakulteta, Maribor (Yugoslavia)

    1989-07-01

    Apart from being exposed to the primary loading of internal pressure and steady temperature field, the reactor pressure vessel is also subject to various thermal transients (thermal shocks). Theoretical and experimental stress analyses show that severe material stresses occur in the nozzle area of the pressure vessel which may lead to defects (cracks). It has been our aim to evaluate these stresses by the use of the Boundary Element method. (author)

  11. Vapor pressure data for ethyl-2-methylbutyrate, hexanal and (E)-2-hexenal at a pressure range of (25 to 190) kPa

    International Nuclear Information System (INIS)

    Meneses, David A.; Bejarano, Arturo; Fuente, Juan C. de la

    2014-01-01

    Highlights: • Vapor pressures of three pure apple aroma constituents were measured. • Measurements were made over the temperature range of (362.1 to 429.9) K. • Constants of Antoine and Wagner type equations were fitted to the experimental data. • Relative deviations (rmsd) from the three vapor-pressure equations were <0.9%. • Contrast with literature showed discrepancies <9% among them and with this work. - Abstract: The saturated vapor pressures of pure ethyl-2-methylbutyrate, hexanal and (E)-2-hexenal, which are volatile compounds characteristic of apple aroma, were measured with a dynamic recirculation apparatus at a pressure range of (24.5 to 190.0) kPa. Measurements were made over the temperature range of (362.1 to 429.9) K for ethyl-2-methylbutyrate, (358.1 to 425.8) K for hexanal, and (373.5 to 446.2) K for (E)-2-hexenal. The maximum likelihood method was used to estimate the parameters of the Antoine equation, whereas the parameters of an extended Antoine equation and the Wagner equation were determined by non linear least square method. The three models showed root mean square deviations (rmsd) of 0.29%, 0.28%, and 0.27% for ethyl-2-methylbutyrate, 0.58%, 0.48%, and 0.38% for hexanal, and 0.89%, 0.62% and 0.36% for (E)-2-hexenal, respectively. Additionally, the experimental data and correlation were compared with those available in the literature

  12. Reaction CH3 + OH studied over the 294-714 K temperature and 1-100 bar pressure ranges.

    Science.gov (United States)

    Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

    2012-08-30

    Reaction of methyl radicals with hydroxyl radicals, CH(3) + OH → products (1) was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 294-714 K temperature and 1-100 bar pressure ranges (bath gas He). Methyl radicals were produced by photolysis of acetone at 193.3 nm. Hydroxyl radicals were generated in reaction of electronically excited oxygen atoms O((1)D), produced in the photolysis of N(2)O at 193.3 nm, with H(2)O. Temporal profiles of CH(3) were recorded via absorption at 216.4 nm using xenon arc lamp and a spectrograph; OH radicals were monitored via transient absorption of light from a dc discharge H(2)O/Ar low pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light inside the reactor was determined by an accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study indicate that the rate constant of reaction 1 is pressure independent within the studied pressure and temperature ranges and has slight negative temperature dependence, k(1) = (1.20 ± 0.20) × 10(-10)(T/300)(-0.49) cm(3) molecule(-1) s(-1).

  13. Direct Numerical Simulation and Theories of Wall Turbulence with a Range of Pressure Gradients

    Science.gov (United States)

    Coleman, G. N.; Garbaruk, A.; Spalart, P. R.

    2014-01-01

    A new Direct Numerical Simulation (DNS) of Couette-Poiseuille flow at a higher Reynolds number is presented and compared with DNS of other wall-bounded flows. It is analyzed in terms of testing semi-theoretical proposals for universal behavior of the velocity, mixing length, or eddy viscosity in pressure gradients, and in terms of assessing the accuracy of two turbulence models. These models are used in two modes, the traditional one with only a dependence on the wall-normal coordinate y, and a newer one in which a lateral dependence on z is added. For pure Couette flow and the Couette-Poiseuille case considered here, this z-dependence allows some models to generate steady streamwise vortices, which generally improves the agreement with DNS and experiment. On the other hand, it complicates the comparison between DNS and models.

  14. Development of a General Shocked-Materials-Response Description for Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Steven M. Valone

    2000-07-01

    This report outlines broad modeling issues pertaining to polymeric materials behavior under detonation conditions. Models applicable system wide are necessary to cope with the broad range of polymers and complex composite forms that can appear in Laboratory weapons systems. Nine major topics are discussed to span the breadth of materials, forms, and physical phenomena encountered when shocking polymers and foams over wide ranges of temperatures, pressures, shock strengths, confinement conditions, and geometries. The recommendations for directions of more intensive investigation consider physical fidelity, computational complexity, and application over widely varying physical conditions of temperature, pressure, and shock strength.

  15. Ranges of diurnal variation and the pattern of body temperature, blood pressure and heart rate in laboratory beagle dogs.

    Science.gov (United States)

    Miyazaki, Hiroyasu; Yoshida, Mutsumi; Samura, Keiji; Matsumoto, Hiroyoshi; Ikemoto, Fumihiko; Tagawa, Masahiro

    2002-01-01

    Ranges in diurnal variation and the patterns of body temperature (T), blood pressure (BP), heart rate (HR) and locomotor activity (LA) in 61 laboratory beagle dogs were analyzed using a telemetry system. Body temperature, BP, HR and LA increased remarkably at feeding time. Locomotor activity increased sporadically during the other periods. Body temperature was maintained at the higher value after feeding but had decreased by 0.2 C by early the next morning. Blood pressure fell to a lower value after feeding but had increased by 2.8% by early the next morning. Heart rate decreased progressively after feeding and was 14.5% lower the next morning. This study determined that in laboratory beagles the ranges of diurnal variation and patterns of T, BP and HR are significantly different from those reported in humans and rodents, and that over 24 hr these physiological changes were associated with their sporadic wake-sleep cycles of the dogs.

  16. High pressure generation by laser driven shock waves: application to equation of state measurement; Generation de hautes pressions par choc laser: application a la mesure d'equations d'etat

    Energy Technology Data Exchange (ETDEWEB)

    Benuzzi, A

    1997-12-15

    This work is dedicated to shock waves and their applications to the study of the equation of state of compressed matter.This document is divided into 6 chapters: 1) laser-produced plasmas and abrasion processes, 2) shock waves and the equation of state, 3) relative measuring of the equation of state, 4) comparison between direct and indirect drive to compress the target, 5) the measurement of a new parameter: the shock temperature, and 6) control and measurement of the pre-heating phase. In this work we have reached relevant results, we have shown for the first time the possibility of generating shock waves of very high quality in terms of spatial distribution, time dependence and of negligible pre-heating phase with direct laser radiation. We have shown that the shock pressure stays unchanged as time passes for targets whose thickness is over 10 {mu}m. A relative measurement of the equation of state has been performed through the simultaneous measurement of the velocity of shock waves passing through 2 different media. The great efficiency of the direct drive has allowed us to produce pressures up to 40 Mbar. An absolute measurement of the equation of state requires the measurement of 2 parameters, we have then performed the measurement of the colour temperature of an aluminium target submitted to laser shocks. A simple model has been developed to infer the shock temperature from the colour temperature. The last important result is the assessment of the temperature of the pre-heating phase that is necessary to know the media in which the shock wave propagates. The comparison of the measured values of the reflectivity of the back side of the target with the computed values given by an adequate simulation has allowed us to deduce the evolution of the temperature of the pre-heating phase. (A.C.)

  17. Validation of the Large Interface Method of NEPTUNE{sub C}FD 1.0.8 for Pressurized Thermal Shock (PTS) applications

    Energy Technology Data Exchange (ETDEWEB)

    Coste, P., E-mail: pierre.coste@cea.fr [CEA, DEN, DER/SSTH, F-38054 Grenoble (France); Lavieville, J. [Electricite de France, Chatou (France); Pouvreau, J. [CEA, DEN, DER/SSTH, F-38054 Grenoble (France); Baudry, C.; Guingo, M.; Douce, A. [Electricite de France, Chatou (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The two-phase Pressurized Thermal Shock (PTS) is a key thermohydraulics issue for PWR safety. Black-Right-Pointing-Pointer The dynamic and condensation models are firstly validated separately. Black-Right-Pointing-Pointer Then the global validation is done with the COSI experiment. Black-Right-Pointing-Pointer All the calculations performed with the same set of models both in the Large Interface Method and in the k-{epsilon} approach for turbulence substantiate the application of the tool to PTS. - Abstract: NEPTUNE{sub C}FD is a code based on a 3D transient Eulerian two-fluid model. One of the main application targets is the two-phase Pressurized Thermal Shock (PTS), which is related to PWR Reactor Pressure Vessel (RPV) lifetime safety studies, when sub-cooled water from Emergency Core Cooling (ECC) system is injected into the possibly uncovered cold leg and penetrates into the RPV downcomer. Five experiments were selected for the validation, a selection reviewed by a panel of European experts. The dynamic models are validated with a co-current smooth and wavy air-water stratified flow in a rectangular channel with detailed measurements of turbulence and velocities. The condensation models are validated with a co-current smooth and wavy steam-water stratified flow in a rectangular channel with measurements of the steam flow rates. The dynamic models are validated in the situation of a jet impinging a pool free surface with two experiments dealing with a water jet impingement on a water pool free surface in air environment. Finally, all the models involved in the reactor conditions are validated with the COSI experiment. The calculations are done with the same set of Large Interface Method models and a RANS (k-{epsilon}) approach for turbulence. They substantiate the application of the tool to PTS studies.

  18. Fast, multiphase volume adaptation to hyperosmotic shock by Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Teuta Pilizota

    Full Text Available All living cells employ an array of different mechanisms to help them survive changes in extra cellular osmotic pressure. The difference in the concentration of chemicals in a bacterium's cytoplasm and the external environment generates an osmotic pressure that inflates the cell. It is thought that the bacterium Escherichia coli use a number of interconnected systems to adapt to changes in external pressure, allowing them to maintain turgor and live in surroundings that range more than two-hundred-fold in external osmolality. Here, we use fluorescence imaging to make the first measurements of cell volume changes over time during hyperosmotic shock and subsequent adaptation on a single cell level in vivo with a time resolution on the order of seconds. We directly observe two previously unseen phases of the cytoplasmic water efflux upon hyperosmotic shock. Furthermore, we monitor cell volume changes during the post-shock recovery and observe a two-phase response that depends on the shock magnitude. The initial phase of recovery is fast, on the order of 15-20 min and shows little cell-to-cell variation. For large sucrose shocks, a secondary phase that lasts several hours adds to the recovery. We find that cells are able to recover fully from shocks as high as 1 Osmol/kg using existing systems, but that for larger shocks, protein synthesis is required for full recovery.

  19. Reaction OH + OH studied over the 298-834 K temperature and 1-100 bar pressure ranges.

    Science.gov (United States)

    Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

    2012-06-21

    Self-reaction of hydroxyl radicals, OH + OH → H(2)O + O (1a) and OH + OH → H(2)O(2) (1b), was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 298-834 K temperature and 1-100 bar pressure ranges (bath gas He). A heatable high-pressure flow reactor was employed. Hydroxyl radicals were prepared using reaction of electronically excited oxygen atoms, O((1)D), produced in photolysis of N(2)O at 193 nm, with H(2)O. The temporal behavior of OH radicals was monitored via transient absorption of light from a dc discharge in H(2)O/Ar low-pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light was determined by accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study combined with the literature data indicate that the rate constant of reaction 1a, associated with the pressure independent component, decreases with temperature within the temperature range 298-414 K and increases above 555 K. The pressure dependent rate constant for (1b) was parametrized using the Troe expression as k(1b,inf) = (2.4 ± 0.6) × 10(-11)(T/300)(-0.5) cm(3) molecule(-1) s(-1), k(1b,0) = [He] (9.0 ± 2.2) × 10(-31)(T/300)(-3.5±0.5) cm(3) molecule(-1) s(-1), F(c) = 0.37.

  20. EURAMET.M.P-S9: comparison in the negative gauge pressure range -950 to 0 hPa

    Science.gov (United States)

    Saxholm, S.; Otal, P.; AltintaS, A.; Bermanec, L. G.; Durgut, Y.; Hanrahan, R.; Kocas, I.; Lefkopoulos, A.; Pražák, D.; Sandu, I.; Åetina, J.; Spohr, I.; Steindl, D.; Tammik, K.; Testa, N.

    2016-01-01

    A comparison in the negative gauge pressure range was arranged in the period 2011 - 2012. A total of 14 laboratories participated in this comparison: BEV (Austria), CMI (Czech Republic), DANIAmet-FORCE (Denmark), EIM (Greece), HMI/FSB-LPM (Croatia), INM (Romania), IPQ (Portugal), LNE (France), MCCAA (Malta), METROSERT (Estonia), MIKES (Finland), MIRS/IMT/LMT (Slovenia), NSAI (Ireland) and UME (Turkey). The project was divided into two loops: Loop1, piloted by MIKES, and Loop2, piloted by LNE. The results of the two loops are reported separately: Loop1 results are presented in this paper. The transfer standard was Beamex MC5 no. 25516865 with internal pressure module INT1C, resolution 0.01 hPa. The nominal pressure range of the INT1C is -1000 hPa to +1000 hPa. The nominal pressure points for the comparison were 0 hPa, -200 hPa, -400 hPa, -600 hPa, -800 hPa and -950 hPa. The reference values and their uncertainties as well as the difference uncertainty between the laboratory results and the reference values were determined from the measurement data by Monte Carlo simulations. Stability uncertainty of the transfer standard was included in the final difference uncertainty. Degrees of equivalences and mutual equivalences between the laboratories were calculated. Each laboratory reported results for all twelve measurement points, which means that there were 168 reported values in total. Some 163 of the 168 values (97 %) agree with the reference values within the expanded uncertainties, with a coverage factor k = 2. Among the laboratories, four different methods were used to determine negative gauge pressure. It is concluded that special attention must be paid to the measurements and methods when measuring negative gauge pressures. There might be a need for a technical guide or a workshop that provides information about details and practices related to the measurements of negative gauge pressure, as well as differences between the different methods. The comparison is

  1. The Use of Limited Fluid Resuscitation and Blood Pressure-Controlling Drugs in the Treatment of Acute Upper Gastrointestinal Hemorrhage Concomitant with Hemorrhagic Shock.

    Science.gov (United States)

    Lu, Bo; Li, Mao-Qin; Li, Jia-Qiong

    2015-06-01

    The aim of this study was to evaluate the usefulness of the limited fluid resuscitation regimen combined with blood pressure-controlling drugs in treating acute upper gastrointestinal hemorrhage concomitant with hemorrhagic shock. A total of 51 patients were enrolled and divided into a group that received traditional fluid resuscitation group (conventional group, 24 patients) and a limited fluid resuscitation group (study group, 27 patients). Before and after resuscitation, the blood lactate, base excess, and hemoglobin values, as well as the volume of fluid resuscitation and resuscitation time were examined. Compared with conventional group, study group had significantly better values of blood lactate, base excess, and hemoglobin (all p controlling drugs effectivelyxxx maintains blood perfusion of vital organs, improves whole body perfusion indicators, reduces the volume of fluid resuscitation, and achieves better bleeding control and resuscitation effectiveness.

  2. High pressure in situ X-ray diffraction study of MnO to 137 GPa and comparison with shock compression experiment

    Science.gov (United States)

    Yagi, T.; Kondo, T.; Syono, Y.

    1998-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment, high pressure in situ X-ray observations were carried out up to 137 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil cell and X-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase was observed above about 40 GPa, which continues to increase up to 90 GPa. Two discontinuous changes of the diffraction profiles were observed at around 90 GPa and 120 GPa. The nature of the intermediate phase between 90 GPa and 120 GPa is not clear yet. It is neither cesium chloride (B2) nor nickel arsenide (B8) structure. On the other hand, the diffraction profile above 120 GPa can be reasonably well explained by the B8 structure. High pressure phases above 90 GPa have metallic luster and all the transformations are reversible on release of pressure.

  3. Analysis of oligomeric transition of silkworm small heat shock protein sHSP20.8 using high hydrostatic pressure native PAGE

    Science.gov (United States)

    Fujisawa, Tetsuro; Ueda, Toshifumi; Kameyama, Keiichi; Aso, Yoichi; Ishiguro, Ryo

    2013-06-01

    The small heat shock proteins (sHSPs) solubilize thermo-denatured proteins without adenosine triphosphate energy consumption to facilitate protein refolding. sHSP20.8 is one of the silkworm (Bombyx mori) sHSPs having only one cystein in the N-terminal domain: Cys43. We report a simple measurement of oligomeric transition of sHSP20.8 using high hydrostatic pressure native polyacrylamide gel electrophoresis (high hydrostatic pressure (HP) native polyacrylamide gel electrophoresis (PAGE)). At ambient pressure under oxydative condition, the native PAGE of thermal transition of sHSP20.8 oligomer displayed a cooperative association. In contrast, HP native PAGE clearly demonstrated that sHSP20.8 dissociated at 80 MPa and 25°C, and the resultant molecular species gradually reassociated with time under that condition. In addition, the reassociation process was suppressed in the presence of the reductant. These results are consistent with the idea that sHSP20.8 oligomer temporally dissociates at the first thermo-sensing step and reassociates with the oxidation of Cys43.

  4. 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 ...

  5. 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.

  6. Prediction of cleavage crack propagation and arrest in a nuclear pressure vessel steel (16MND5) under thermal shock

    International Nuclear Information System (INIS)

    Yang, Xiaoyu

    2015-01-01

    the critical stress was developed. The results of this analytical model is in good agreement with the empirical criterion identified. In order to test the validity of the identified criterion, the prediction of the crack propagation and arrest by the criterion was first performed for isothermal tests. It was performed both on CT25 specimens (crack was solicited in mode I) and on ring specimens in mixed mode loading which were carried out at three different temperatures. The numerical results of prediction were in good agreement with experiments. They showed the validity of the criterion for experiments under isothermal loading for two different specimen geometries. In order to test the validity of criterion for the situation of thermal shock, experiments were carried out on ring specimens. At first, one ring specimen was cooled down to -150 C, and then hot water (∼90 C) was injected through the inner side of the ring specimen. At the same time of thermal shock, this specimen was submitted to a mechanical compressive loading (-750 kN). The prediction of crack propagation and arrest by the criterion for this situation was calculated in both 2D and 3D. The predicted results were in good agreement with experiments for both crack speed and crack length. This confirmed that the criterion is relevant to predict the crack propagation and arrest for thermal shock. In parallel, some experiments were performed on extended CT25 specimens (same height but double the width of the CT25 specimen). The crack path on this kind of specimen was curved. A statistical effect by a random selection in the propagation direction was introduced to take into account the instability during the crack propagation. The numerical results correctly reproduce the curvature and the dispersion of the crack paths. (author) [fr

  7. 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)

  8. Improvement of the calculation of the stress intensity factors for underclad and through-clad defects in a reactor pressure vessel subjected to a pressurised thermal shock

    International Nuclear Information System (INIS)

    Marie, S.; Chapuliot, S.

    2008-01-01

    The analysis of the stability of a defect in a cladded reactor pressure vessel (RPV) of a nuclear pressure water reactor (PWR) subjected to pressurised thermal shock (PTS) is one main elements of the general safety demonstration. Recently, CEA proposed several improved analytical tools for the analysis of the PTS. First, an analytical solution for the vessel through-thickness temperature variation has been developed to deal with any fluid temperature, taking into account the possible presence of a cladding, in the case of an internal PTS. The associated thermal stress expression has been simplified and a complete linearised solution is given for the thermal loading and also for internal pressure, depending on the main vessel material and on the cladding properties. Finally, a complete compendium is also given for the elastic stresses intensity factor calculation. This paper proposes several improvements of the proposed analytical method to deal with a PTS in a PWR cladded vessel. A variable heat transfer coefficient is now taken into account based on an equivalent fluid temperature variation determination, associated with a constant heat transfer coefficient, to keep the same thermal exchange between the fluid and the inner skin of the vessel obtained with the initial data. A more accurate expression for the linearised stresses due to the internal pressure is given, and a possible effect of residual stresses due to the difference between the operating temperature and the stress-free temperature is also taken into account. Finally, an extension of the domain of definition of the influence functions for the elastic stress intensity factor calculation is given

  9. Molecular dynamics simulations of ejecta production from sinusoidal tin surfaces under supported and unsupported shocks

    Science.gov (United States)

    Wu, Bao; Wu, FengChao; Zhu, YinBo; Wang, Pei; He, AnMin; Wu, HengAn

    2018-04-01

    Micro-ejecta, an instability growth process, occurs at metal/vacuum or metal/gas interface when compressed shock wave releases from the free surface that contains surface defects. We present molecular dynamics (MD) simulations to investigate the ejecta production from tin surface shocked by supported and unsupported waves with pressures ranging from 8.5 to 60.8 GPa. It is found that the loading waveforms have little effect on spike velocity while remarkably affect the bubble velocity. The bubble velocity of unsupported shock loading remains nonzero constant value at late time as observed in experiments. Besides, the time evolution of ejected mass in the simulations is compared with the recently developed ejecta source model, indicating the suppressed ejection of unmelted or partial melted materials. Moreover, different reference positions are chosen to characterize the amount of ejecta under different loading waveforms. Compared with supported shock case, the ejected mass of unsupported shock case saturates at lower pressure. Through the analysis on unloading path, we find that the temperature of tin sample increases quickly from tensile stress state to zero pressure state, resulting in the melting of bulk tin under decaying shock. Thus, the unsupported wave loading exhibits a lower threshold pressure causing the solid-liquid phase transition on shock release than the supported shock loading.

  10. Molecular dynamics simulations of ejecta production from sinusoidal tin surfaces under supported and unsupported shocks

    Directory of Open Access Journals (Sweden)

    Bao Wu

    2018-04-01

    Full Text Available Micro-ejecta, an instability growth process, occurs at metal/vacuum or metal/gas interface when compressed shock wave releases from the free surface that contains surface defects. We present molecular dynamics (MD simulations to investigate the ejecta production from tin surface shocked by supported and unsupported waves with pressures ranging from 8.5 to 60.8 GPa. It is found that the loading waveforms have little effect on spike velocity while remarkably affect the bubble velocity. The bubble velocity of unsupported shock loading remains nonzero constant value at late time as observed in experiments. Besides, the time evolution of ejected mass in the simulations is compared with the recently developed ejecta source model, indicating the suppressed ejection of unmelted or partial melted materials. Moreover, different reference positions are chosen to characterize the amount of ejecta under different loading waveforms. Compared with supported shock case, the ejected mass of unsupported shock case saturates at lower pressure. Through the analysis on unloading path, we find that the temperature of tin sample increases quickly from tensile stress state to zero pressure state, resulting in the melting of bulk tin under decaying shock. Thus, the unsupported wave loading exhibits a lower threshold pressure causing the solid-liquid phase transition on shock release than the supported shock loading.

  11. 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

  12. Association of different electrocardiographic patterns with shock index, right ventricle systolic pressure and diameter, and embolic burden score in pulmonary embolism

    Directory of Open Access Journals (Sweden)

    Krća Bojana

    2016-01-01

    Full Text Available Background/Aim. Some electrocardiographic (ECG patterns are characteristic for pulmonary embolism but exact meaning of the different ECG signs are not well known. The aim of this study was to determine the association between four common ECG signs in pulmonary embolism [complete or incomplete right bundle branch block (RBBB, S-waves in the aVL lead, S1Q3T3 sign and negative T-waves in the precordial leads] with shock index (SI, right ventricle diastolic diameter (RVDD and peak systolic pressure (RVSP and embolic burden score (EBS. Methods. The presence of complete or incomplete RBBB, S waves in aVL lead, S1Q3T3 sign and negative T-waves in the precordial leads were determined at admission ECG in 130 consecutive patients admitted to the intensive care unit of a single tertiary medical center in a 5-year period. Echocardiography examination with measurement of RVDD and RVSP, multidetector computed tomography pulmonary angiography (MDCT-PA with the calculation of EBS and SI was determined during the admission process. Multivariable regression models were calculated with ECG parameters as independent variables and the mentioned ultrasound, MDCT-PA parameters and SI as dependent variables. Results. The presence of S-waves in the aVL was the only independent predictor of RVDD (F = 39.430, p < 0.001; adjusted R2 = 0.231 and systolic peak right ventricle pressure (F = 29.903, p < 0.001; adjusted R2 = 0.185. Negative T-waves in precordial leads were the only independent predictor for EBS (F = 24.177, p < 0.001; R2 = 0.160. Complete or incomplete RBBB was the independent predictor of SI (F = 20.980, p < 0.001; adjusted R2 = 0.134. Conclusion. In patients with pulmonary embolism different ECG patterns at admission correlate with different clinical, ultrasound and MDCT-PA parameters. RBBB is associated with shock, Swave in the aVL is associated with right ventricle pressure and negative T-waves with the thrombus burden in the pulmonary tree.

  13. Preliminary development of an integrated approach to the evaluation of pressurized thermal shock as applied to the Oconee Unit 1 Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Burns, T J; Cheverton, R D; Flanagan, G F; White, J D; Ball, D G; Lamonica, L B; Olson, R

    1986-05-01

    An evaluation of the risk to the Oconee-1 nuclear plant due to pressurized thermal shock (PTS) has been Completed by Oak Ridge National Laboratory (ORNL). This evaluaion was part of a Nuclear Regulatory Commission (NRC) program designed to study the PTS risk to three nuclear plants: Oconee-1, a Babcock and Wilco reactor plant owned and operated by Duke Power Company; Calvert Cliffs-1, a Combustion Engineering reactor plant owned and operated by Baltimore Gas and Electric company; and H.B. Robinson-2, a Westinghouse reactor plant owned and operated by Carolina Power and Light Company. Studies of Calvert Cliffs-1 and H.B. Robinson-2 are still underway. The specific objectives of the Oconee-1 study were to: (1) provide a best estimate of the probability of a through-the-wall crack (TWC) occurring in the reactor pressure vessel as a result of PTS; (2) determine dominant accident sequences, plant features, operator and control actions and uncertainty in the PTS risk; and (3) evaluate effectiveness of potential corrective measures.

  14. 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

  15. Laser shocks: A tool for experimental simulation of damage into materials

    Energy Technology Data Exchange (ETDEWEB)

    Boustie, M.; Cuq Lelandais, J. P.; Berthe, L.; Ecault, R. [Institut PPRIME, Departement Physique et Mecanique des Materiaux, CNRS-ENSMA-Universite de Poitiers, 1 av Clement Ader, 86961 FUTUROSCOPE Cedex (France); CEA-DAM Valduc, 21120 Is-sur-Tille (France); Laboratoire Procedes et Ingenierie en Mecanique et Materiaux (CNRS), Arts et Metiers ParisTech, 151 bd de l' Hopital, 75013 PARIS (France); Institut PPRIME, Departement Physique et Mecanique des Materiaux, CNRS-ENSMA-Universite de Poitiers, 1 av Clement Ader, 86961 FUTUROSCOPE Cedex (France)

    2012-07-30

    High power laser irradiation of solids results in a strong shock wave propagation, driving very high amplitude pressure loadings with very short durations. These particular characteristics offer the possibility to study the behaviour of matter under extreme dynamic conditions in continuity with what is possible with the conventional generators of shock (launchers of projectiles, explosives). An advantage of laser shocks is a possible recovery of the shocked samples presenting the metallurgical effects of the shock in most cases. We introduce the principle of the laser shock generation, the characterization of these shocks, the principal mechanisms and effects associated with their propagation in the solids. We show how laser shocks can be a laboratory tool for simulating shock effects at ultra high strain rate, providing a high in information experimental layout for validation of damage modelling on an extended strain rate range compared to conventional shock generators. New data have been obtained with ultra short femtosecond range irradiation. Experimental data gathered through post mortem observation, time resolved velocity measurement are shown along with numerical associated simulations, showing the possibility to predict the damage behaviour of metallic targets under extreme strain rate up to 10{sup 8} s{sup -1}.

  16. Shock-induced synthesis of high temperature superconducting materials

    Science.gov (United States)

    Ginley, D.S.; Graham, R.A.; Morosin, B.; Venturini, E.L.

    1987-06-18

    It has now been determined that the unique features of the high pressure shock method, especially the shock-induced chemical synthesis technique, are fully applicable to high temperature superconducting materials. Extraordinarily high yields are achievable in accordance with this invention, e.g., generally in the range from about 20% to about 99%, often in the range from about 50% to about 90%, lower and higher yields, of course, also being possible. The method of this invention involves the application of a controlled high pressure shock compression pulse which can be produced in any conventional manner, e.g., by detonation of a high explosive material, the impact of a high speed projectile or the effect of intense pulsed radiation sources such as lasers or electron beams. Examples and a discussion are presented.

  17. A low-power tool for measuring acceleration, pressure, and temperature (APT) with wide dynamic range and bandwidth

    Science.gov (United States)

    Heesemann, Martin; Davis, Earl E.; Paros, Jerome; Johnson, Greg; Meldrum, Robert; Scherwath, Martin; Mihaly, Steven

    2017-04-01

    We present a new tool that facilitates the study of inter-related geodetic, geodynamic, seismic, and oceanographic phenomena. It incorporates a temperature compensated tri-axial accelerometer developed by Quartz Seismic Sensors, Inc., a pressure sensor built by Paroscientific Inc., and a low-power, high-precision frequency counter developed by Bennest Enterprises Ltd. and built by RBR, Ltd. The sensors are housed in a 7 cm o.d. titanium pressure case designed for use to full ocean depths (withstands more than 20 km of water pressure). Sampling intervals are programmable from 0.08 s to 1 hr; standard memory can store up to 130 million samples; total power consumption is roughly 115 mW when operating continuously and proportionately lower when operating intermittently (e.g., 2 mW average at 1 sample per min). Serial and USB communications protocols allow a variety of autonomous and cable-connection options. Measurement precision of the order of 10-8 of full scale (e.g., pressure equivalent to 4000 m water depth, acceleration = +/- 3 g) allows observations of pressure and acceleration variations of 0.4 Pa and 0.3 μm s-2. Long-term variations in vertical acceleration are sensitive to displacement through the gravity gradient down to a level of roughly 2 cm, and variations in horizontal acceleration are sensitive to tilt down to a level of 0.03 μrad. With the large dynamic ranges, high sensitivities and broad bandwidth (6 Hz to DC), ground motion associated with microseisms, strong and weak seismic ground motion, tidal loading, and slow and rapid geodynamic deformation - all normally studied using disparate instruments - can be observed with a single tool. Installation in the marine environment is accomplished by pushing the tool roughly 1 m vertically below the seafloor with a submersible or remotely operated vehicle, with no profile remaining above the seafloor to cause current-induced noise. The weight of the tool is designed to match the sediment it displaces to

  18. Pressure shock triploidization of Salmo trutta f. lacustris and Salvelinus umbla eggs and its impact on fish development.

    Science.gov (United States)

    Lahnsteiner, Franz; Kletzl, Manfred

    2018-07-15

    The study tested the efficiency of hydrostatic pressure triploidization methods for Salmo trutta f. lacustris and Salvelinus umbla and investigated the effects on survival rate, skeletal malformation, and on morphometrics and cellular composition of gills, spleen, liver, kidney, intestine, and blood. In Salmo trutta f. lacustris a 100% triploidy rate in combination with high larvae survival rate (80% in comparison to control) was obtained when treating eggs with a pressure of 66 × 10 3  kPa 360 °C temperature minutes (CTM) post fertilization for 5 min, in Salvelinus umbla with a similar pressure after 270 CTM. Juvenile triploid Salmo trutta f. lacustris and Salvelinus umbla (145 days post hatch) had neither an increased rate of mortality, nor an increased rate of malformations. In triploid Salmo trutta f. lacustris and Salvelinus umbla the erythrocyte volume was 50% higher and the erythrocyte concentration in peripheral blood 25-35% lower relative to diploids. In triploids also the erythrocytes surface area: volume ratio was reduced. Gills of triploid Salmo trutta f. lacustris and Salvelinus umbla had increased width of primary lamellae and increased length of secondary lamellae which might compensate for unfavorable erythrocytes surface area: volume ratio. Length of the digestive tract and histology of kidney, liver, spleen, and gills were only investigated in Salmo trutta f. lacustris. In triploids the hematopoietic tissue of the kidney was decreased by 12%, the spleen index by 53%, and the erythroblast concentrations of the spleen by 42% relative to diploids, possibly indicating reduced erythropoiesis. Length of the digestive tract and cellular arrangement of intestine, liver, and gills were not affected. In summary, the used triploidization procedure seems a reliable method not counteracting the principles of animal welfare. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. Part 1: Pressure distribution

    Science.gov (United States)

    Messiter, A. F.

    1979-01-01

    Analytical solutions are derived which incorporate additional physical effects as higher order terms for the case when the sonic line is very close to the wall. The functional form used for the undisturbed velocity profile is described to indicate how various parameters will be calculated for later comparison with experiment. The basic solutions for the pressure distribution are derived. Corrections are added for flow along a wall having longitudinal curvature and for flow in a circular pipe, and comparisons with available experimental data are shown.

  20. High pressure phase equilibrium of ternary and multicomponent alkane mixtures in the temperature range from (283–473) K

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Liu, Yiqun; Wibowo, Ahmad A.

    2017-01-01

    /n-butane/n-octane/n-dodecane/n-hexadecane/n-eicosane as model reservoir fluids and measured their phase equilibrium in the temperature range from (283–473) K by using a variable volume cell with full visibility. Their phase envelopes and liquid volume fractions below the saturation pressure have been measured. Four equations of state, including Soave......-Redlich-Kwong (SRK), Peng-Robinson (PR), Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT), and Soave-Benedict-Webb-Rubin (Soave-BWR), have been used to predict phase equilibrium of the measured systems. PR and PC-SAFT give better results than others and Soave-BWR gives poor phase envelope predictions...

  1. Converging cylindrical magnetohydrodynamic shock collapse onto a power-law-varying line current

    KAUST Repository

    Mostert, W.

    2016-03-16

    We investigate the convergence behaviour of a cylindrical, fast magnetohydrodynamic (MHD) shock wave in a neutrally ionized gas collapsing onto an axial line current that generates a power law in time, azimuthal magnetic field. The analysis is done within the framework of a modified version of ideal MHD for an inviscid, non-dissipative, neutrally ionized compressible gas. The time variation of the magnetic field is tuned such that it approaches zero at the instant that the shock reaches the axis. This configuration is motivated by the desire to produce a finite magnetic field at finite shock radius but a singular gas pressure and temperature at the instant of shock impact. Our main focus is on the variation with shock radius, as, of the shock Mach number and pressure behind the shock as a function of the magnetic field power-law exponent, where gives a constant-in-time line current. The flow problem is first formulated using an extension of geometrical shock dynamics (GSD) into the time domain to take account of the time-varying conditions ahead of the converging shock, coupled with appropriate shock-jump conditions for a fast, symmetric MHD shock. This provides a pair of ordinary differential equations describing both and the time evolution on the shock, as a function of, constrained by a collapse condition required to achieve tuned shock convergence. Asymptotic, analytical results for and are obtained over a range of for general, and for both small and large . In addition, numerical solutions of the GSD equations are performed over a large range of, for selected parameters using . The accuracy of the GSD model is verified for some cases using direct numerical solution of the full, radially symmetric MHD equations using a shock-capturing method. For the GSD solutions, it is found that the physical character of the shock convergence to the axis is a strong function of . For μ≤0.816, and both approach unity at shock impact owing to the dominance of the strong

  2. Experimental Investigation of Diffuser Pressure-ratio Control with Shock-positioning Limit on 28-inch Ram-jet Engine

    Science.gov (United States)

    Dunbar, William R; Wentworth, Carl B; Crowl, Robert J

    1957-01-01

    The performance of a control system designed for variable thrust applications was determined in an altitude free-jet facility at various Mach numbers, altitudes and angles of attack for a wide range of engine operation. The results are presented as transient response characteristics for step disturbances in fuel flow and stability characteristics as a function of control constants and engine operating conditions. The results indicate that the control is capable of successful operation over the range of conditions tested, although variations in engine gains preclude optimum response characteristics at all conditions with fixed control constants.

  3. A pressurized ion chamber monitoring system for environmental radiation measurements utilizing a wide-range temperature-compensated electrometer

    International Nuclear Information System (INIS)

    Stevenick, W. Van

    1994-01-01

    The performance of a complete pressurized ion chamber (PIC) radiation monitoring system is described. The design incorporates an improved temperature-compensated electrometer which is stable to ±3 · 10 -16 A over the environmental range of temperature (-40 to +40 C). Using a single 10 11 Ω feed-back resistor, the electrometer accurately measures currents over a range from 3 · 10 -15 A to 3 · 10 -11 A. While retaining the sensitivity of the original PIC system (the instrument responds readily to small background fluctuations on the order of 0.1 μR h -1 ), the new system measures radiation levels up to the point where the collection efficiency of the ion chamber begins to drop off, typically ∼27 pA at 1 mR h -1 . A data recorder and system controller was designed using the Tattletale trademark Model 4A computer. Digital data is stored on removable solid-state, credit-card style memory cards

  4. Possible pressurized thermal shock events during large primary to secondary leakage. The Hungarian AGNES project and PRISE accident scenarios in VVER-440/V213 type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Perneczky, L. [KFKI Atomic Energy Research Inst., Budabest (Hungary)

    1997-12-31

    Nuclear power plants of WWER-440/213-type have several special features. Consequently, the transient behaviour of such a reactor system should be different from the behaviour of the PWRs of western design. The opening of the steam generator (SG) collector cover, as a specific primary to secondary circuit leakage (PRISE) occurring in WWER-type reactors happened first time in Rovno NPP Unit I on January 22, 1982. Similar accident was studied in the framework of IAEA project RER/9/004 in 1987-88 using the RELAP4/mod6 code. The Hungarian AGNES (Advanced General and New Evaluation of Safety) project was performed in the period 1991-94 with the aim to reassess the safety of the Paks NPP using state-of-the-art techniques. The project comprised three type of analyses for the primary to secondary circuit leakages: Design Basis Accident (DBA) analyses, Pressurized Thermal Shock (PTS) study and deterministic analyses for Probabilistic Safety Analysis (PSA). Major part of the thermohydraulic analyses has been performed by the RELAP5/mod2.5/V251 code version with two input models. 32 refs.

  5. Possible pressurized thermal shock events during large primary to secondary leakage. The Hungarian AGNES project and PRISE accident scenarios in VVER-440/V213 type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Perneczky, L [KFKI Atomic Energy Research Inst., Budabest (Hungary)

    1998-12-31

    Nuclear power plants of WWER-440/213-type have several special features. Consequently, the transient behaviour of such a reactor system should be different from the behaviour of the PWRs of western design. The opening of the steam generator (SG) collector cover, as a specific primary to secondary circuit leakage (PRISE) occurring in WWER-type reactors happened first time in Rovno NPP Unit I on January 22, 1982. Similar accident was studied in the framework of IAEA project RER/9/004 in 1987-88 using the RELAP4/mod6 code. The Hungarian AGNES (Advanced General and New Evaluation of Safety) project was performed in the period 1991-94 with the aim to reassess the safety of the Paks NPP using state-of-the-art techniques. The project comprised three type of analyses for the primary to secondary circuit leakages: Design Basis Accident (DBA) analyses, Pressurized Thermal Shock (PTS) study and deterministic analyses for Probabilistic Safety Analysis (PSA). Major part of the thermohydraulic analyses has been performed by the RELAP5/mod2.5/V251 code version with two input models. 32 refs.

  6. Attachment to the REh-1301 spectrometer for study on substances in the temperature range 120-350 K at pressure 1-1O4 atm

    International Nuclear Information System (INIS)

    Filippov, A.I.

    1979-01-01

    A design of an attachment for an electron paramagnetic resonance spectrometer is described, which allows investigations of substances over the 120-350 K temperature range at the pressures of 1 to 10 4 atm. To create a required pressure the high-pressure bomb is screwed by means of a special nut into the low-pressure system. The high-pressure vessel is made of a single piece of beryllium bronze. The temperature is measured with the help of a thermocouple, and the pressure - by a manganine manometer. Temperature isolation of the high-thermal insulation of the high-pressure bomb make it possible to adjust the temperature with an accuracy of +-1 K or better

  7. Fuel-coolant interactions in a shock-tube geometry

    International Nuclear Information System (INIS)

    Segev, A.; Henry, R.E.; Bankoff, S.G.

    1978-01-01

    Thermal interactions were studied in a shock tube configuration using different pairs of liquids. Large pressures were obtained for systems of water-Wood's metal and butanol-Wood's metal. Different types of interactions were observed, depending on the hot liquid temperature. It was found that thehydrodynamic component alone may account for the measured pressure in the lower temperature range. A combination of thermal and hydrodynamic interactions accounts for the pressures at high temperatures. Experiments with water and molten salt (LiCl + KCl) produced small scale explosions. All interactions were suppressed when driving pressure increased. (author)

  8. Thermo-emf of cadmium under hydrostatic pressure up to 3.0 GPa in the range of electron-topological transition

    International Nuclear Information System (INIS)

    Krajdenov, V.F.; Itskevich, E.S.; Gapotchenko, A.G.

    1995-01-01

    Dependence of longitudinal d and transverse α thermo-emf of cadmium in 4-300 K temperature range at pressures up to 3.0 GPa was investigated. The anomaly value depends sufficiently on sample perfection

  9. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, E. R.; Sim, S. A., E-mail: parkin@mso.anu.edu.au, E-mail: s.sim@qub.ac.uk [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia)

    2013-04-20

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L{sub X}, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L{sub X}/L{sub bol}). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  10. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    International Nuclear Information System (INIS)

    Parkin, E. R.; Sim, S. A.

    2013-01-01

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L X , remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L X /L bol ). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  11. Compact streak camera for the shock study of solids by using the high-pressure gas gun

    Science.gov (United States)

    Nagayama, Kunihito; Mori, Yasuhito

    1993-01-01

    For the precise observation of high-speed impact phenomena, a compact high-speed streak camera recording system has been developed. The system consists of a high-pressure gas gun, a streak camera, and a long-pulse dye laser. The gas gun installed in our laboratory has a muzzle of 40 mm in diameter, and a launch tube of 2 m long. Projectile velocity is measured by the laser beam cut method. The gun is capable of accelerating a 27 g projectile up to 500 m/s, if helium gas is used as a driver. The system has been designed on the principal idea that the precise optical measurement methods developed in other areas of research can be applied to the gun study. The streak camera is 300 mm in diameter, with a rectangular rotating mirror which is driven by an air turbine spindle. The attainable streak velocity is 3 mm/microsecond(s) . The size of the camera is rather small aiming at the portability and economy. Therefore, the streak velocity is relatively slower than the fast cameras, but it is possible to use low-sensitivity but high-resolution film as a recording medium. We have also constructed a pulsed dye laser of 25 - 30 microsecond(s) in duration. The laser can be used as a light source of observation. The advantage for the use of the laser will be multi-fold, i.e., good directivity, almost single frequency, and so on. The feasibility of the system has been demonstrated by performing several experiments.

  12. 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.

  13. [Predictive value of central venous-to-arterial carbon dioxide partial pressure difference for fluid responsiveness in septic shock patients: a prospective clinical study].

    Science.gov (United States)

    Liu, Guangyun; Huang, Huibin; Qin, Hanyu; Du, Bin

    2018-05-01

    To evaluate the accuracy of central venous-to-arterial carbon dioxide partial pressure difference (Pcv-aCO 2 ) before and after rapid rehydration test (fluid challenge) in predicting the fluid responsiveness in patients with septic shock. A prospective observation was conducted. Forty septic shock patients admitted to medical intensive care unit (ICU) of Peking Union Medical College Hospital from October 2015 to June 2017 were enrolled. All of the patients received fluid challenge in the presence of invasive hemodynamic monitoring. Heart rate (HR), blood pressure, cardiac index (CI), Pcv-aCO 2 and other physiological variables were recorded at 10 minutes before and immediately after fluid challenge. Fluid responsiveness was defined as an increase in CI greater than 10% after fluid challenge, whereas fluid non-responsiveness was defined as no increase or increase in CI less than 10%. The correlation between Pcv-aCO 2 and CI was explored by Pearson correlation analysis. Receiver operating characteristic (ROC) curves were established to evaluate the discriminatory abilities of baseline and the changes after fluid challenge in Pcv-aCO 2 and other physiological variables to define the fluid responsiveness. The patients were separated into two groups according to the initial value of Pcv-aCO 2 . The cut-off value of 6 mmHg (1 mmHg = 0.133 kPa) was chosen according to previous studies. The discriminatory abilities of baseline and the change in Pcv-aCO 2 (ΔPcv-aCO 2 ) were assessed in each group. A total of 40 patients were finally included in this study. Twenty-two patients responded to the fluid challenge (responders). Eighteen patients were fluid non-responders. There was no significant difference in baseline physiological variable between the two groups. Fluid challenge could increase CI and blood pressure significantly, decrease HR notably and had no effect on Pcv-aCO 2 in fluid responders. In non-responders, blood pressure was increased significantly and CI, HR, Pcv

  14. 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)

  15. 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.

  16. 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.

  17. Composite Liner, Multi-Megabar Shock Driver Development

    International Nuclear Information System (INIS)

    Cochrane, J.C. Jr.; Bartsch, R.R.; Clark, D.A.; Morgan, D.V.; Anderson, W.E.; Lee, H.; Bowers, R.L.; Atchison, W.L.; Oona, H.; Stokes, J.L.; Veeser, L.R.; Broste, W.B.

    1998-01-01

    The multi-megabar shock driver development is a series of experiments in support of the Los Alamos High Energy Density Physics Experimental Program. Its purpose is to develop techniques to impact a uniform, stable, composite liner upon a high Z target to produce a multi-megabar shock for EOS studies. To date, experiments have been done on the Pegasus II capacitor bank with a current of approximately12MA driving the impactor liner. The driving field is approximately200 T at the target radius of 1cm. Data will be presented on the impactor liner. The driving field is approximately200 T at the target radius of 1 cm. Data will be presented on the stability and uniformity of the impactor liner when it impacts the target cylinder. Three experiments have been done with emphasis on liner development. Shock pressures greater than a megabar have been done with emphasis on liner development. Shock pressures greater than a megabar have been produced with an Al target cylinder. A Pt target cylinder should produce shock pressures in th e 5-megabar range

  18. Electrical conductivity measurements in shock compressed liquid nitrogen

    International Nuclear Information System (INIS)

    Hamilton, D.C.; Mitchell, A.C.; Nellis, W.J.

    1985-06-01

    The electrical conductivity of shock compressed liquid nitrogen was measured in the pressure range 20 to 50 GPa using a two-stage light-gas gun. The conductivities covered a range 4 x 10 -2 to 1 x 10 2 ohm -1 cm -1 . The data are discussed in terms of a liquid semiconductor model below the onset of the dissociative phase transition at 30 GPa. 15 refs., 1 fig

  19. 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.

  20. 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)

  1. 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

  2. Electric gun: a new tool for ultrahigh-pressure research

    International Nuclear Information System (INIS)

    Weingart, R.C.; Chau, H.H.; Goosman, D.R.; Hofer, W.W.; Honodel, C.A.; Lee, R.S.; Steinberg, D.J.; Stroud, J.R.

    1979-01-01

    We have developed a new tool for ultrahigh-pressure research at LLL. This system, which we call the electric gun, has already achieved thin flyer plate velocities in excess of 20 km/s and pressures of the order of 2 TPa in tantalum. We believe that the electric gun is competitive with laser- and nuclear-driven methods of producing shocks in the 1-to-5 TPa range because of its precision and ease and economy of operation. Its development is recommended for shock initiation studies, dry runs for Site 300 hydroshots, and as a shock wave generator for surface studies

  3. Dynamic pressure sensitivity determination with Mach number method

    Science.gov (United States)

    Sarraf, Christophe; Damion, Jean-Pierre

    2018-05-01

    Measurements of pressure in fast transient conditions are often performed even if the dynamic characteristic of the transducer are not traceable to international standards. Moreover, the question of a primary standard in dynamic pressure is still open, especially for gaseous applications. The question is to improve dynamic standards in order to respond to expressed industrial needs. In this paper, the method proposed in the EMRP IND09 ‘Dynamic’ project, which can be called the ‘ideal shock tube method’, is compared with the ‘collective standard method’ currently used in the Laboratoire de Métrologie Dynamique (LNE/ENSAM). The input is a step of pressure generated by a shock tube. The transducer is a piezoelectric pressure sensor. With the ‘ideal shock tube method’ the sensitivity of a pressure sensor is first determined dynamically. This method requires a shock tube implemented with piezoelectric shock wave detectors. The measurement of the Mach number in the tube allows an evaluation of the incident pressure amplitude of a step using a theoretical 1D model of the shock tube. Heat transfer, other actual effects and effects of the shock tube imperfections are not taken into account. The amplitude of the pressure step is then used to determine the sensitivity in dynamic conditions. The second method uses a frequency bandwidth comparison to determine pressure at frequencies from quasi-static conditions, traceable to static pressure standards, to higher frequencies (up to 10 kHz). The measurand is also a step of pressure generated by a supposed ideal shock tube or a fast-opening device. The results are provided as a transfer function with an uncertainty budget assigned to a frequency range, also deliverable frequency by frequency. The largest uncertainty in the bandwidth of comparison is used to trace the final pressure step level measured in dynamic conditions, owing that this pressure is not measurable in a steady state on a shock tube. A reference

  4. 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.

  5. 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 ...

  6. Shock-induced decomposition of a high density glass (ZF6)

    Science.gov (United States)

    Zhou, Xianming; Liu, Xun; Li, Jiabo; Li, Jun; Cao, Xiuxia

    2011-07-01

    The dynamic high-pressure behavior of a high density glass (ZF6) was investigated in this study. The Hugoniot data, shock temperature (TH) and release sound velocity (C) of ZF6 were measured by a time-resolved multi-channel pyrometer in the shock pressure (PH) range of 50-170 GPa. The Hugoniot data is in accord with the Los Alamos Scientific Laboratory (LASL) shock Hugoniot data and shows a good linearity over 21 GPa. Polymorphic phase transitions were identified by the kinks in the measured TH-PH and C-PH relationships. The onset pressures of the transformations are ˜75 and ˜128 GPa, respectively. A thermodynamic calculation suggests that the phase transition at 75 GPa is its disproportionation to massicot (high pressure phase of PbO) and melted silica while the transition at 128 GPa is from the melting of massicot.

  7. 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)

  8. Investigation of Shock-Induced Reactions in a Ni+Al Powder Mixture

    International Nuclear Information System (INIS)

    Eakins, D. E.; Thadhani, N. N.

    2006-01-01

    The shock-compression and reaction response of equi-volumetric micron-scale (∼50-60% dense) spherical nickel and aluminum powder mixtures is investigated in the range of the calculated crush-up pressure (P = 0.4 GPa) and up to 6 GPa. Time resolved stress measurements (using PVDF gauges) coupled with VISAR data is used to determine the shock states. Evidence of reaction or lack thereof is inferred by comparing the measured states with calculated Hugoniot state of reaction products based on the ballotechnic model proposed by Bennett and Horie, (Shock Waves 4:127-136). Post-impact micro-structural analysis of recovered material and comparison of calculated and measured product states is used to establish the criterion for reaction occurring in the shock or post-shock states

  9. A study of the structural stability of TiC, TiN and TiO in the pressure range up to 65 GPa using synchrotron radiation

    International Nuclear Information System (INIS)

    Noerlund Christensen, A.; Gerward, L.; Staun Olsen, J.; Steenstrup, S.

    1990-01-01

    Structural phase transformations in TiC, TiN and TiO could possibly occur at high pressure because of the non-stoichiometric nature of these compounds. The NaCl structure could then possibly transform to the CsCl structure, in which case the coordination number would increase from six to eight. This is in agreement with the general rule that the coordination number increases with pressure. The present work was undertaken in order to investigate possible structural phase transformations in TiC, TiN and TiO in the pressure range up to 65 GPa (=650 kbar). (orig.)

  10. Use of the nine-step inflation/deflation test and resting middle-ear pressure range as predictors of middle-ear barotrauma in aircrew members.

    Science.gov (United States)

    Hussein, A; Abousetta, A

    2014-07-01

    To explore the role of the nine-step inflation/deflation tympanometric test and resting middle-ear pressure range as predictors of barotrauma in aircrew members. A prospective, non-randomised study was conducted on 100 aircrew members. Resting middle-ear pressure was measured and the nine-step inflation/deflation test performed on all subjects before flights. Subjects were allocated to two groups according to resting middle-ear pressure range (group A, within the range of +26 to +100 and -26 to -100 mmH2O; group B, -25 to +25 mmH2O). All aircrew members were assessed after flights regarding the presence and the grade of barotrauma. In both groups, the sensitivity and specificity values of the entire post-inflation/deflation test were close to those of the post-deflation part of the test. The post-deflation test had a higher negative predictive value than the post-inflation test. Ears with resting middle-ear pressure lower than -55 mmH2O experienced barotrauma, regardless of good or poor post-inflation or post-deflation test results. In an aircrew member, a resting middle-ear pressure within the range of -55 and +50 mmH2O, together with good post-deflation test results, are considered reliable predictors for fitness to fly.

  11. 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.

  12. 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: ...

  13. 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

  14. Elastic-plastic fracture mechanics study of thermal shock cracking

    International Nuclear Information System (INIS)

    Hirano, K.; Kobayashi, H.; Nakazawa, H.

    1980-01-01

    This paper describes thermal shock experiments conducted on a nuclear pressure vessel steel (A533 Grade B Class 1), an AISI304 steel and a tool steel (JIS SKD62) using both a new thermal shock test facility and method. Analysis of their quasi-static thermal stress intensity factors is performed on the basis of linear-elastic fracture mechanics; and a thermal shock fracture toughness value, Ksub(tsc) is evaluated. Then elastic-plastic fracture toughness tests are carried out in the same high temperature range of the thermal shock experiment, and a relation between the stretched zone width, SZW, formed as a result of the fatigue precrack tip plastic blunting and the J-integral is clarified. An elastic-plastic thermal shock fracture toughness value, Jsub(tsc), is evaluated from a critical value of the stretched zone width, SZWsub(tsc), at the initiation of the thermal shock cracking by using the relation between SZW and J. The Jsub(tsc) value is compared with an elastic-plastic fracture toughness value, Jsub(Ic), and the difference between these Jsub(tsc) and Jsub(Ic) values is discussed on the basis of fractography. (author)

  15. 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.

  16. 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

  17. Prehospital shock index and pulse pressure/heart rate ratio to predict massive transfusion after severe trauma: Retrospective analysis of a large regional trauma database.

    Science.gov (United States)

    Pottecher, Julien; Ageron, François-Xavier; Fauché, Clémence; Chemla, Denis; Noll, Eric; Duranteau, Jacques; Chapiteau, Laurent; Payen, Jean-François; Bouzat, Pierre

    2016-10-01

    Early and accurate detection of severe hemorrhage is critical for a timely trigger of massive transfusion (MT). Hemodynamic indices combining heart rate (HR) and either systolic (shock index [SI]) or pulse pressure (PP) (PP/HR ratio) have been shown to track blood loss during hemorrhage. The present study assessed the accuracy of prehospital SI and PP/HR ratio to predict subsequent MT, using the gray-zone approach. This was a retrospective analysis (January 1, 2009, to December 31, 2011) of a prospectively developed trauma registry (TRENAU), in which the triage scheme combines patient severity and hospital facilities. Thresholds for MT were defined as either classic (≥10 red blood cell units within the first 24 hours [MT1]) or critical (≥3 red blood cells within the first hour [MT2]). The receiver operating characteristic curves and gray zones were defined for SI and PP/HR ratio to predict MT1 and MT2 and faced with initial triage scheme. The TRENAU registry included 3,689 trauma patients, of which 2,557 had complete chart recovery and 176 (6.9%) required MT. In the whole population, PP/HR ratio and SI moderately and similarly predicted MT1 (area under the receiver operating characteristic curve, 0.77 [95% confidence interval {CI}, 0.70-0.84] and 0.80 [95% CI, 0.74-0.87], respectively, p = 0.064) and MT2 (0.71 [95% CI, 0.67-0.76] and 0.72 [95% CI, 0.68-0.77], respectively, p = 0.48). The proportions of patients in the gray zone for PP/HR ratio and SI were 61% versus 40%, respectively, to predict MT1 (p ratio outperformed SI to predict MT2 (0.72 [95% CI, 0.59-0.84] vs. 0.54 [95% CI, 0.33-0.74]; p ratio were moderately accurate in predicting MT. In the seemingly least severe patients, an improvement of prehospital undertriage for MT may be gained by using the PP/HR ratio. Epidemiolgic study, level III.

  18. Syn-eruptive, soft-sediment deformation of deposits from dilute pyroclastic density current: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves

    Science.gov (United States)

    Douillet, G. A.; Taisne, B.; Tsang-Hin-Sun, E.; Muller, S. K.; Kueppers, U.; Dingwell, D. B.

    2015-05-01

    Soft-sediment deformation structures can provide valuable information about the conditions of parent flows, the sediment state and the surrounding environment. Here, examples of soft-sediment deformation in deposits of dilute pyroclastic density currents are documented and possible syn-eruptive triggers suggested. Outcrops from six different volcanoes have been compiled in order to provide a broad perspective on the variety of structures: Soufriere Hills (Montserrat), Tungurahua (Ecuador), Ubehebe craters (USA), Laacher See (Germany), and Tower Hill and Purrumbete lakes (both Australia). The variety of features can be classified in four groups: (1) tubular features such as pipes; (2) isolated, laterally oriented deformation such as overturned or oversteepened laminations and vortex-shaped laminae; (3) folds-and-faults structures involving thick (>30 cm) units; (4) dominantly vertical inter-penetration of two layers such as potatoids, dishes, or diapiric flame-like structures. The occurrence of degassing pipes together with basal intrusions suggest fluidization during flow stages, and can facilitate the development of other soft-sediment deformation structures. Variations from injection dikes to suction-driven, local uplifts at the base of outcrops indicate the role of dynamic pore pressure. Isolated, centimeter-scale, overturned beds with vortex forms have been interpreted to be the signature of shear instabilities occurring at the boundary of two granular media. They may represent the frozen record of granular, pseudo Kelvin-Helmholtz instabilities. Their recognition can be a diagnostic for flows with a granular basal boundary layer. Vertical inter-penetration and those folds-and-faults features related to slumps are driven by their excess weight and occur after deposition but penecontemporaneous to the eruption. The passage of shock waves emanating from the vent may also produce trains of isolated, fine-grained overturned beds that disturb the surface bedding

  19. 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.

  20. Thermal hydraulic evaluation for an experimental facility to investigate pressurized thermal shock (PTS) in CDTN/CNEN; Avaliacao termo-hidraulica da montagem experimental de choque termico pressurizado do CDTN/CNEN

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, Elcio T.; Navarro, Moyses A.; Aronne, Ivam D.; Terra, Jose L. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)

    2002-07-01

    The goal of the work presented in this paper is to provide necessary thermal hydraulics information to the design of an experimental installation to investigate the Pressurized Thermal Shock (PTS) to be implemented at Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN). The envisaged installation has a test section that represents, in a small scale, a pressure vessel of a nuclear reactor. This test section will be heated and then exposed to a PTS in order to evaluate the appearance and development of cracks. To verify the behavior of the temperatures of the pressure vessel after a sudden flood through the annulus, calculations were made using the RELAP5/MOD 3.2.2 gamma code. Different outer radiuses were studied for the annular region. The results showed that the smaller annulus spacing (20 mm) anticipates the wetting of the surface and produces a higher cooling of the external surface, which stays completely wet for a longer time. (author)

  1. 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...

  2. Investigating Multiphase Flow Phenomena in Fine-Grained Reservoir Rocks: Insights from Using Ethane Permeability Measurements over a Range of Pore Pressures

    Directory of Open Access Journals (Sweden)

    Eric Aidan Letham

    2018-01-01

    Full Text Available The ability to quantify effective permeability at the various fluid saturations and stress states experienced during production from shale oil and shale gas reservoirs is required for efficient exploitation of the resources, but to date experimental challenges prevent measurement of the effective permeability of these materials over a range of fluid saturations. To work towards overcoming these challenges, we measured effective permeability of a suite of gas shales to gaseous ethane over a range of pore pressures up to the saturated vapour pressure. Liquid/semiliquid ethane saturation increases due to adsorption and capillary condensation with increasing pore pressure resulting in decreasing effective permeability to ethane gas. By how much effective permeability to ethane gas decreases with adsorption and capillary condensation depends on the pore size distribution of each sample and the stress state that effective permeability is measured at. Effective permeability decreases more at higher stress states because the pores are smaller at higher stress states. The largest effective permeability drops occur in samples with dominant pore sizes in the mesopore range. These pores are completely blocked due to capillary condensation at pore pressures near the saturated vapour pressure of ethane. Blockage of these pores cuts off the main fluid flow pathways in the rock, thereby drastically decreasing effective permeability to ethane gas.

  3. 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.

  4. 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

  5. Calibration of PCB-132 Sensors in a Shock Tube

    Science.gov (United States)

    Berridge, Dennis C.; Schneider, Steven P.

    2012-01-01

    While PCB-132 sensors have proven useful for measuring second-mode instability waves in many hypersonic wind tunnels, they are currently limited by their calibration. Until now, the factory calibration has been all that was available, which is a single-point calibration at an amplitude three orders of magnitude higher than a second-mode wave. In addition, little information has been available about the frequency response or spatial resolution of the sensors, which is important for measuring high-frequency instability waves. These shortcomings make it difficult to compare measurements at different conditions and between different sensors. If accurate quantitative measurements could be performed, comparisons of the growth and breakdown of instability waves could be made in different facilities, possibly leading to a method of predicting the amplitude at which the waves break down into turbulence, improving transition prediction. A method for calibrating the sensors is proposed using a newly-built shock tube at Purdue University. This shock tube, essentially a half-scale version of the 6-Inch shock tube at the Graduate Aerospace Laboratories at Caltech, has been designed to attain a moderate vacuum in the driven section. Low driven pressures should allow the creation of very weak, yet still relatively thin shock waves. It is expected that static pressure rises within the range of second-mode amplitudes should be possible. The shock tube has been designed to create clean, planar shock waves with a laminar boundary layer to allow for accurate calibrations. Stronger shock waves can be used to identify the frequency response of the sensors out to hundreds of kilohertz.

  6. 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.

  7. Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Ruiz, F. J.; Blas, F. J., E-mail: felipe@uhu.es [Departamento de Física Aplicada, Universidad de Huelva, 21071 Huelva (Spain); Centro de Investigación de Física Teórica y Matemática, Universidad de Huelva, 21071 Huelva (Spain); Mendiboure, B. [Laboratoire des Fluides Complexes et leurs Réservoirs, UMR5150, Université de Pau et des Pays de l’Adour, B. P. 1155, Pau Cedex 64014 (France); Moreno-Ventas Bravo, A. I. [Centro de Investigación de Física Teórica y Matemática, Universidad de Huelva, 21071 Huelva (Spain); Departamento de Geología, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain)

    2014-11-14

    We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r{sub c} = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r{sub c} = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial

  8. Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

    International Nuclear Information System (INIS)

    Martínez-Ruiz, F. J.; Blas, F. J.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.

    2014-01-01

    We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r c = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r c = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness

  9. Experimental research on crossing shock wave boundary layer interactions

    Science.gov (United States)

    Settles, G. S.; Garrison, T. J.

    1994-10-01

    An experimental research effort of the Penn State Gas Dynamics Laboratory on the subject of crossing shock wave boundary layer interactions is reported. This three year study was supported by AFOSR Grant 89-0315. A variety of experimental techniques were employed to study the above phenomena including planar laser scattering flowfield visualization, kerosene lampblack surface flow visualization, laser-interferometer skin friction surveys, wall static pressure measurements, and flowfield five-hole probe surveys. For a model configuration producing two intersecting shock waves, measurements were made for a range of oblique shock strengths at freestream Mach numbers of 3.0 and 3.85. Additionally, measurements were made at Mach 3.85 for a configuration producing three intersecting waves. The combined experimental dataset was used to formulate the first detailed flowfield models of the crossing-shock and triple-shock wave/boundary layer interactions. The structure of these interactions was found to be similar over a broad range of interaction strengths and is dominated by a large, separated, viscous flow region.

  10. Simulation of hypersonic shock wave - laminar boundary layer interactions

    Science.gov (United States)

    Kianvashrad, N.; Knight, D.

    2017-06-01

    The capability of the Navier-Stokes equations with a perfect gas model for simulation of hypersonic shock wave - laminar boundary layer interactions is assessed. The configuration is a hollow cylinder flare. The experimental data were obtained by Calspan-University of Buffalo (CUBRC) for total enthalpies ranging from 5.07 to 21.85 MJ/kg. Comparison of the computed and experimental surface pressure and heat transfer is performed and the computed §ow¦eld structure is analyzed.

  11. Low upper-shelf toughness, high transition temperature test insert in HSST [Heavy Section Steel Technology] PTSE-2 [Pressurized Thermal Shock Experiment-2] vessel and wide plate test specimens: Final report

    International Nuclear Information System (INIS)

    Domian, H.A.

    1987-02-01

    A piece of A387, Grade 22 Class 2 (2-1/4 Cr - 1 Mo) steel plate specially heat treated to produce low upper-shelf (LUS) toughness and high transition temperature was installed in the side wall of Heavy Section Steel Technology (HHST) vessel V-8. This vessel is to be tested by the Oak Ridge National Laboratory (ORNL) in the Pressurized Thermal Shock Experiment-2 (PTSE-2) project of the HSST program. Comparable pieces of the plate were made into six wide plate specimens and other samples. These samples underwent tensile tests, Charpy tests, and J-integral tests. The results of these tests are given in this report

  12. Vapour pressures for 1-(butoxymethoxy)butane (dibutoxymethane) and 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxybutane (methyl nonafluorobutyl ether) over the pressure range of (15–80) kPa

    International Nuclear Information System (INIS)

    Gárate, María P.; Bejarano, Arturo; Fuente, Juan C. de la

    2016-01-01

    Highlights: • Vapour pressures of two pure potential dry-cleaning solvent were measured. • Measurements were made over the temperature range of (294.6–442.7) K. • Three commonly used vapour pressure equations were fitted to the experimental data. • The parameters of Antoine and Wagner type equations were estimated. • The relative deviations (rmsd) from the three vapour-pressure equations were <0.6%. - Abstract: Saturated pressures of 1-(butoxymethoxy)butane (dibutoxymethane) and 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxybutane (methyl nonafluorobutyl ether), new potential solvents for dry-cleaning processes, were measured with a dynamic recirculation apparatus at a pressure range of (15–80) kPa, at temperatures of (390.4–442.7) K for dibutoxymethane and (294.6–322.4) K for methyl nonafluorobutyl ether. The vapour pressures were represented using the correlations of Antoine, extended Antoine and Wagner with relative root mean square deviations of, 1%, 6% and 0.6% for dibutoxymethane, and, 1%, 2% and 0.6% for methyl nonafluorobutyl ether, respectively. The experimental data of dibutoxymethane was compared with those available in literature, the result showed consistency between both data sets.

  13. Thermophysical and thermodynamic properties of ionic liquids over an extended pressure range: [bmim][NTf2] and [hmim][NTf2

    International Nuclear Information System (INIS)

    Gomes de Azevedo, R.; Esperanca, J.M.S.S.; Szydlowski, J.; Visak, Z.P.; Pires, P.F.; Guedes, H.J.R.; Rebelo, L.P.N.

    2005-01-01

    The current study focuses on 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [bmim][NTf 2 ], and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [hmim][NTf 2 ]. The objective is to study the influence of pressure as well as that of the cation's alkyl chain length on several properties of this type of ionic liquids. Speed of propagation of ultrasound waves and densities in pure ionic liquids (ILs) as a function of temperature and pressure have been determined. Several other thermodynamic properties such as compressibilities, expansivities and heat capacities have been obtained. Speed of sound measurements have been carried out in broad ranges of temperature (283 < T/K < 323) and pressure (0.1 < p/MPa < 150), using a non-intrusive microcell. Density measurements have been performed at broad ranges of temperature (298 < T/K < 333) and pressure (0.1 < p/MPa < 60) using a vibrating tube densimeter. The pressure dependence of heat capacities, which is generally mild, is highly dependent on the curvature of the temperature dependence of density

  14. 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.

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

    KAUST Repository

    Javed, Tamour

    2016-12-29

    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. Such measurements may potentially be affected by some non-ideal phenomena. The purpose of this work is to measure long ignition delay times for fuels exhibiting negative temperature coefficient (NTC) and to assess the impact of shock tube non-idealities on ignition delay data. Ignition delay times of n-heptane and n-hexane were measured over the temperature range of 650 – 1250 K and pressures near 1.5 atm. Driver gas tailoring and long length of shock tube driver section were utilized to measure ignition delay times as long as 32 ms. Measured ignition delay times agree with chemical kinetic models at high (> 1100 K) and low (< 700 K) temperatures. In the intermediate temperature range (700 – 1100 K), however, significant discrepancies are observed between the measurements and homogeneous ignition delay simulations. It is postulated, based on experimental observations, that localized ignition kernels could affect the ignition delay times at the intermediate temperatures, which lead to compression (and heating) of the bulk gas and result in expediting the overall ignition event. The postulate is validated through simple representative computational fluid dynamic simulations of post-shock gas mixtures which exhibit ignition advancement via a hot spot. The results of the current work show that ignition delay times measured by shock tubes may be affected by non-ideal phenomena for certain conditions of temperature, pressure and fuel reactivity. Care must, therefore, be exercised in using such data for chemical kinetic model development and validation.

  16. Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters

    International Nuclear Information System (INIS)

    Renaud, M; Goedbloed, M; De Nooijer, C; Van Schaijk, R; Fujita, T

    2015-01-01

    Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture. (paper)

  17. Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters

    Science.gov (United States)

    Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.

    2015-10-01

    Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.

  18. Mixed butanols addition to gasoline surrogates: Shock tube ignition delay time measurements and chemical kinetic modeling

    KAUST Repository

    AlRamadan, Abdullah S.; Badra, Jihad; Javed, Tamour; Alabbad, Mohammed; Bokhumseen, Nehal; Gaillard, Patrick; Babiker, Hassan; Farooq, Aamir; Sarathy, Mani

    2015-01-01

    work, the effect of mixed butanols addition to gasoline surrogates has been investigated in a high-pressure shock tube facility. The ignition delay times of mixed butanols stoichiometric mixtures were measured at 20 and 40bar over a temperature range

  19. High temperature science: future needs and anticipated development in high-density shock-wave research

    International Nuclear Information System (INIS)

    Ross, M.; Ahrens, T.J.; Nellis, W.J.

    1979-01-01

    Shock-wave experiments on condensed matter currently achieve pressures up to 5 Mbar, and temperatures over 20,000 0 K. In this report we survey a number of experimental methods that, in the next decade, may increase the conditions by an order of magnitude. These advanced experiments will allow us to investigate a new range of physics problems

  20. Thermodynamics of aqueous methyldiethanolamine (MDEA) and methyldiethanolammonium chloride (MDEAH+Cl-) over a wide range of temperature and pressure: Apparent molar volumes, heat capacities, and isothermal compressibilities

    International Nuclear Information System (INIS)

    Hawrylak, B.; Palepu, R.; Tremaine, Peter R.

    2006-01-01

    Apparent molar volumes of aqueous methyldiethanolamine and its salt were determined with platinum vibrating tube densitometers over a range of temperatures from 283K= o , heat capacities C p o , and isothermal compressibilities κ T o . The standard partial molar volumes V o for the neutral amine and its salt show increasingly positive and negative values, respectively, at high temperatures and pressures, as predicted by corresponding states and group additivity arguments. The density model and the revised Helgeson-Kirkham-Flowers (HKF) model have been used to represent the temperature and pressure dependence of the standard partial molar properties to yield a full thermodynamic description of the system

  1. WSC-2: a subchannel dryout correlation for water-cooled clusters over the pressure range 3.4-15.9 MPA (500-2300 PSIA)

    International Nuclear Information System (INIS)

    Bowring, R.W.

    1979-05-01

    WSC-2 is a subchannel dryout correlation for use with subchannel analysis computer codes such as HAMBO. It was optimised from 1074 experimental data points from 54 clusters simulating Pressure Tube Reactor, BWR and PWR geometries and covering the pressure range 3.4-15.9 MPa. The correlation errors were(a) PWR - type data: RMS 8.8%, Mean 0.2%,(b) all classes of data: RMS 7.2%, Mean - 0.3%. This represents a significant improvement over the other correlations used for reactor assessment with which it has been compared. (author)

  2. Study of laser-driven shock wave propagation in Plexiglas targets

    International Nuclear Information System (INIS)

    Dhareshwar, L.J.; Naik, P.A.; Pant, H.C.; Kaushik, T.C.

    1992-01-01

    An experimental study of laser-driven shock wave propagation in a transparent material such as Plexiglas using a high-speed optical shadowgraphy technique is presented in this paper. A Nd: glass laser was used to produce laser intensity in the range 10 12 -10 14 W/cm 2 on the target. Optical shadowgrams of the propagating shock front were recorded with a second-harmonic (0.53-μm) optical probe beam. Shock pressures were measured at various laser intensities, and the scaling was found to agree with the theoretically predicted value. Shock pressure values have also been obtained from a one-dimensional Lagrangian hydrodynamic simulation, and they match well with experimental results. Shadowgrams of shock fronts produced by nonuniform spatial laser beam irradiation profiles have shown complete smoothing when targets with a thin coating of a material of high atomic number such as gold were used. Shock pressures in such coated targets are also found to be considerably higher compared with those in uncoated targets. (Author)

  3. 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- ...

  4. 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.

  5. 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.

  6. 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.

  7. Constraining the Depth of a Martian Magma Ocean through Metal-Silicate Partitioning Experiments: The Role of Different Datasets and the Range of Pressure and Temperature Conditions

    Science.gov (United States)

    Righter, K.; Chabot, N.L.

    2009-01-01

    Mars accretion is known to be fast compared to Earth. Basaltic samples provide a probe into the interior and allow reconstruction of siderophile element contents of the mantle. These estimates can be used to estimate conditions of core formation, as for Earth. Although many assume that Mars went through a magma ocean stage, and possibly even complete melting, the siderophile element content of Mars mantle is consistent with relatively low pressure and temperature (PT) conditions, implying only shallow melting, near 7 GPa and 2073 K. This is a pressure range where some have proposed a change in siderophile element partitioning behavior. We will examine the databases used for parameterization and split them into a low and higher pressure regime to see if the methods used to reach this conclusion agree for the two sets of data.

  8. Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 deg. C

    International Nuclear Information System (INIS)

    Dureja, A.K.; Sinha, S.K.; Srivastava, Ankit; Sinha, R.K.; Chakravartty, J.K.; Seshu, P.; Pawaskar, D.N.

    2011-01-01

    Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 deg. C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce's correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.

  9. 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

  10. Hydrogen gas inhalation inhibits progression to the "irreversible" stage of shock after severe hemorrhage in rats.

    Science.gov (United States)

    Matsuoka, Tadashi; Suzuki, Masaru; Sano, Motoaki; Hayashida, Kei; Tamura, Tomoyoshi; Homma, Koichiro; Fukuda, Keiichi; Sasaki, Junichi

    2017-09-01

    Mortality of hemorrhagic shock primarily depends on whether or not the patients can endure the loss of circulating volume until radical treatment is applied. We investigated whether hydrogen (H2) gas inhalation would influence the tolerance to hemorrhagic shock and improve survival. Hemorrhagic shock was achieved by withdrawing blood until the mean arterial blood pressure reached 30-35 mm Hg. After 60 minutes of shock, the rats were resuscitated with a volume of normal saline equal to four times the volume of shed blood. The rats were assigned to either the H2 gas (1.3% H2, 26% O2, 72.7% N2)-treated group or the control gas (26% O2, 74% N2)-treated group. Inhalation of the specified gas mixture began at the initiation of blood withdrawal and continued for 2 hours after fluid resuscitation. The survival rate at 6 hours after fluid resuscitation was 80% in H2 gas-treated rats and 30% in control gas-treated rats (p gas-treated rats than in the control rats. Despite losing more blood, the increase in serum potassium levels was suppressed in the H2 gas-treated rats after 60 minutes of shock. Fluid resuscitation completely restored blood pressure in the H2 gas-treated rats, whereas it failed to fully restore the blood pressure in the control gas-treated rats. At 2 hours after fluid resuscitation, blood pressure remained in the normal range and metabolic acidosis was well compensated in the H2 gas-treated rats, whereas we observed decreased blood pressure and uncompensated metabolic acidosis and hyperkalemia in the surviving control gas-treated rats. H2 gas inhalation delays the progression to irreversible shock. Clinically, H2 gas inhalation is expected to stabilize the subject until curative treatment can be performed, thereby increasing the probability of survival after hemorrhagic shock.

  11. Shock-induced transformations in crystalline RDX: a uniaxial constant-stress Hugoniostat molecular dynamics simulation study.

    Science.gov (United States)

    Bedrov, Dmitry; Hooper, Justin B; Smith, Grant D; Sewell, Thomas D

    2009-07-21

    Molecular dynamics (MD) simulations of uniaxial shock compression along the [100] and [001] directions in the alpha polymorph of hexahydro-1,3,5-trinitro-1,3,5-triazine (alpha-RDX) have been conducted over a wide range of shock pressures using the uniaxial constant stress Hugoniostat method [Ravelo et al., Phys. Rev. B 70, 014103 (2004)]. We demonstrate that the Hugoniostat method is suitable for studying shock compression in atomic-scale models of energetic materials without the necessity to consider the extremely large simulation cells required for an explicit shock wave simulation. Specifically, direct comparison of results obtained using the Hugoniostat approach to those reported by Thompson and co-workers [Phys. Rev. B 78, 014107 (2008)] based on large-scale MD simulations of shocks using the shock front absorbing boundary condition (SFABC) approach indicates that Hugoniostat simulations of systems containing several thousand molecules reproduced the salient features observed in the SFABC simulations involving roughly a quarter-million molecules, namely, nucleation and growth of nanoscale shear bands for shocks propagating along the [100] direction and the polymorphic alpha-gamma phase transition for shocks directed along the [001] direction. The Hugoniostat simulations yielded predictions of the Hugoniot elastic limit for the [100] shock direction consistent with SFABC simulation results.

  12. 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

  13. 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

  14. 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

  15. 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

  16. Ab initio calculation of the shear viscosity of neon in the liquid and hypercritical state over a wide pressure and temperature range

    Science.gov (United States)

    Eggenberger, Rolf; Gerber, Stefan; Huber, Hanspeter; Searles, Debra; Welker, Marc

    1992-08-01

    The shear viscosity is calculated ab initio for the liquid and hypercritical state, i.e. a previously published potential for Ne 2, obtained from ab initio calculations including electron correlation, is used in classical equilibrium molecular dynamics simulations to obtain the shear viscosity from a Green-Kubo integral. The quality of the results is quite uniform over a large pressure range up to 1000 MPa and a wide temperature range from 26 to 600 K. In most cases the calculated shear viscosity deviates by less than 10% from the experimental value, in general the error being only a few percent.

  17. Effects of C5/C6 Intervertebral Space Distraction Height on Pressure on the Adjacent Intervertebral Disks and Articular Processes and Cervical Vertebrae Range of Motion.

    Science.gov (United States)

    Lu, Tingsheng; Luo, Chunshan; Ouyang, Beiping; Chen, Qiling; Deng, Zhongliang

    2018-04-25

    BACKGROUND This study aimed to investigate the association between range of motion of the cervical vertebrae and various C5/C6 intervertebral space distraction heights. MATERIAL AND METHODS The cervical vertebrae from 6 fresh adult human cadavers were used to prepare the models. Changes in C4/C5 and C6/C7 intervertebral disk pressures, articular process pressure, and range of motion of the cervical vertebrae before and after the distraction of the C5/C6 intervertebral space at benchmark heights of 100%, 120%, 140%, and 160% were tested under different exercise loads. RESULTS The pressure on the adjacent intervertebral disks was highest with the standing upright position before distraction, varied with different positions of the specimens and distraction heights after distraction, and was closest to that before distraction at a distraction height of 120% (Particular processes was highest with left and right rotations before distraction, varied with different positions of the specimens and distraction heights after distraction, and was lowest under the same exercise load with different positions at a distraction height of 120% (Pdistraction and at a distraction height of 120% after distraction, respectively (Particular processes and range of motion of the cervical vertebrae and is therefore an appropriate intervertebral space distraction height.

  18. Mars on Earth: Analog basaltic soils and particulates from Lonar Crater, India, include Deccan soil, shocked soil, reworked lithic and glassy ejecta, and both shocked and unshocked baked zones

    Science.gov (United States)

    Wright, S. P.

    2017-12-01

    "There is no perfect analog for Mars on Earth" [first line of Hipkin et al. (2013) Icarus, 261-267]. However, fieldwork and corresponding sample analyses from laboratory instrumentation (to proxy field instruments) has resulted in the finding of unique analog materials that suggest that detailed investigations of Lonar Crater, India would be beneficial to the goals of the Mars Program. These are briefly described below as Analog Processes, Materials, and Fieldwork. Analog Processes: The geologic history of Lonar Crater emulates localities on Mars with 1.) flood basaltic volcanism with interlayer development of 2.) baked zones or "boles" and 3.) soil formation. Of six flows, the lower three are aqueously altered by groundwater to produce a range of 4.) alteration products described below. The impact event 570 ka produced a range of 5.) impactites including shocked baked zones, shocked soils, and altered basalt shocked to a range of shock pressures [Kieffer et al., 1976]. Analog Materials: 65 Ma Deccan basalt contains augite and labradorite. Baked zones are higher in hematite and other iron oxides. Soil consists of calcite and organic matter. Several basalts with secondary alteration are listed here and these mirror alteration on Mars: hematite, chlorite, serpentine, zeolite, and palagonite, with varying combinations of these with primary igneous minerals. All of these materials (#1 through 4 above) are shocked to a range of shocked pressures to produce maskelynite, flowing plagioclase glass, vesiculated plagioclase glass, and complete impact melts. Shocked soils contain schlieren calcite amidst comminuted grains of augite, labradorite, and these glasses. Shocked baked zones unsurprisingly have a petrographic texture similar to hornfels, another product of contact metamorphism. Analog Fieldwork: The ejecta consists of two layers: 8 m of lithic breccia with unshocked and fractured basalts under a 1 m suevite consisting of all ranges of shock pressure described above

  19. 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.   

  20. Shock compression experiments on Lithium Deuteride single crystals.

    Energy Technology Data Exchange (ETDEWEB)

    Knudson, Marcus D.; Desjarlais, Michael Paul; Lemke, Raymond W.

    2014-10-01

    S hock compression exper iments in the few hundred GPa (multi - Mabr) regime were performed on Lithium Deuteride (LiD) single crystals . This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17 - 32 km/s. Measurements included pressure, density, and temperature between %7E200 - 600 GPa along the Principal Hugoniot - the locus of end states achievable through compression by large amplitude shock waves - as well as pressure and density of re - shock states up to %7E900 GPa . The experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  1. Characteristics of shock waves in neutrino-thick medium of collapsing stars

    International Nuclear Information System (INIS)

    Imshennik, V.S.; Murzina, M.V.

    1989-01-01

    Hugoniot relations for shock waves in neutrino-thick medium of colapsing stars are formulated. The equations obtained are solved numerically for rather wide range of shock wave velocities (D=(1,3,5)x10 9 cm/s) as well as for values of medium physical parameters against the shock wave front ( temperature T=(3,5,10)x1 -9 K; medium degree Θ 0 =n n /n p =10;100; at ρ 0 =10 11 g/cm 3 density).Presence of neutrino radiation is shown to result in matter essential deneutronization (up to Θ=10-30) at shock wave passage though contribution of leptonic component into the matter main characteristics (pressure, internal energy, temperature etc.) is rather small. 17 refs.; 3 figs.; 3 tabs

  2. 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.

  3. Maximization of energy recovery inside supersonic separator in the presence of condensation and normal shock wave

    International Nuclear Information System (INIS)

    Shooshtari, S.H. Rajaee; Shahsavand, A.

    2017-01-01

    Natural gases provide around a quarter of energy consumptions around the globe. Supersonic separators (3S) play multifaceted role in natural gas industry processing, especially for water and hydrocarbon dew point corrections. These states of the art devices have minimum energy requirement and favorable process economy compared to conventional facilities. Their relatively large pressure drops may limit their application in some situations. To maximize the energy recovery of the dew point correction facility, the pressure loss across the 3S unit should be minimized. The optimal structure of 3s unit (including shock wave location and diffuser angle) is selected using simultaneous combination of normal shock occurrence and condensation in the presence of nucleation and growth processes. The condense-free gas enters the non-isentropic normal shock wave. The simulation results indicate that the normal shock location, pressure recovery coefficient and onset position strongly vary up to a certain diffuser angle (β = 8°) with the maximum pressure recovery of 0.88 which leads to minimum potential energy loss. Computational fluid dynamic simulations show that separation of boundary layer does not happen for the computed optimal value of β and it is essentially constant when the inlet gas temperatures and pressures vary over a relatively broad range. - Highlights: • Supersonic separators have found numerous applications in oil and gas industries. • Maximum pressure recovery is crucial for such units to maximize energy efficiency. • Simultaneous condensation and shock wave occurrence are studied for the first time. • Diverging nozzle angle of 8° can provide maximum pressure recovery of 0.88. • The optimal diffuser angle remains constant over a broad range of inlet conditions.

  4. Experimental Insights into the Mechanisms of Particle Acceleration by Shock Waves

    Science.gov (United States)

    Scolamacchia, T.; Scheu, B.; Dingwell, D. B.

    2011-12-01

    The generation of shock waves is common during explosive volcanic eruptions. Particles acceleration following shock wave propagation has been experimentally observed suggesting the potential hazard related to this phenomenon. Experiments and numerical models focused on the dynamics of formation and propagation of different types of shock waves when overpressurized eruptive mixtures are suddenly released in the atmosphere, using a pseudo-gas approximation to model those mixtures. Nevertheless, the results of several studies indicated that the mechanism of coupling between a gas and solid particles is valid for a limited grain-size range, which at present is not well defined. We are investigating particle acceleration mechanisms using a vertical shock tube consisting of a high-pressure steel autoclave (450 mm long, 28 mm in diameter), pressurized with argon, and a low-pressure 140 mm long acrylic glass autoclave, with the same internal diameter of the HP reservoir. Shock waves are generated by Ar decompression at atmospheric pressures at Pres/Pamb 100:1 to 150:1, through the failure of a diaphragm. Experiments were performed either with empty autoclave or suspending solid analogue particles 150 μm in size inside the LP autoclave. Incident Mach number varied from 1.7 to 2.1. Absolute and relative pressure sensors monitored P histories during the entire process, and a high-speed camera recorded particles movement at 20,000 to 30,000 fps. Preliminary results indicate pressure multiplication at the contact between shock waves and the particles in a time lapse of 100s μs, suggesting a possible different mechanism with respect to gas-particle coupling for particle acceleration.

  5. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression

    International Nuclear Information System (INIS)

    Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.

    2010-01-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  6. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression

    Science.gov (United States)

    Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.

    2010-08-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ˜6km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  7. Measurements of (p, ρ, T) properties for isobutane in the temperature range from 280 K to 440 K at pressures up to 200 MPa

    International Nuclear Information System (INIS)

    Miyamoto, H.; Uematsu, M.

    2006-01-01

    Measurements of (p, ρ, T) properties for isobutane in the compressed liquid phase have been obtained by means of a metal-bellows variable volumometer in the temperature range from 280 K to 440 K at pressures up to 200 MPa. The volume-fraction purity of isobutane used was 0.9999. The expanded uncertainties (k = 2) of temperature, pressure, and density measurements have been estimated to be less than 3 mK, 1.5 kPa (p ≤ 7 MPa), 0.06% (7 MPa 150 MPa), and 0.11%, respectively. In region more than 100 MPa at 280 K and 440 K, the uncertainty in density measurements rise up to 0.15% and 0.23%, respectively. The differences of the present density values at the same temperature between two series of measurements, in which the sample fillings are different, are within the maximum deviation of 0.09% in density, which is enough lower than the expanded uncertainty in density. Eight (p, ρ, T) measurements at the same temperatures and pressures as the literature values have been conducted for comparison. In addition, vapour pressures were measured at T = (280, 300) K. Moreover, the comparisons of the available equations of state with the present measurements are reported

  8. Flexible Polydimethylsiloxane Foams Decorated with Multiwalled Carbon Nanotubes Enable Unprecedented Detection of Ultralow Strain and Pressure Coupled with a Large Working Range.

    Science.gov (United States)

    Iglio, Rossella; Mariani, Stefano; Robbiano, Valentina; Strambini, Lucanos; Barillaro, Giuseppe

    2018-04-25

    Low-cost piezoresistive strain/pressure sensors with large working range, at the same time able to reliably detect ultralow strain (≤0.1%) and pressure (≤1 Pa), are one of the challenges that have still to be overcome for flexible piezoresistive materials toward personalized health-monitoring applications. In this work, we report on unprecedented, simultaneous detection of ultrasmall strain (0.1%, i.e., 10 μm displacement over 10 mm) and subtle pressure (20 Pa, i.e., a force of only 2 mN over an area of 1 cm 2 ) in compression mode, coupled with a large working range (i.e., up to 60% for strain-6 mm in displacement-and 50 kPa for pressure) using piezoresistive, flexible three-dimensional (3D) macroporous polydimethylsiloxane (pPDMS) foams decorated with pristine multiwalled carbon nanotubes (CNTs). pPDMS/CNT foams with pore size up to 500 μm (i.e., twice the size of those of commonly used foams, at least) and porosity of 77%, decorated with a nanostructured surface network of CNTs at densities ranging from 7.5 to 37 mg/cm 3 are prepared using a low-cost and scalable process, through replica molding of sacrificial sugar templates and subsequent drop-casting of CNT ink. A thorough characterization shows that piezoresistive properties of the foams can be finely tuned by controlling the CNT density and reach an optimum at a CNT density of 25 mg/cm 3 , for which a maximum change of the material resistivity (e.g., ρ 0 /ρ 50 = 4 at 50% strain) is achieved under compression. Further static and dynamic characterization of the pPDMS/CNT foams with 25 mg/cm 3 of CNTs highlights that detection limits for strain and pressure are 0.03% (3 μm displacement over 10 mm) and 6 Pa (0.6 mN over an area of 1 cm 2 ), respectively; moreover, good stability and limited hysteresis are apparent by cycling the foams with 255 compression-release cycles over the strain range of 0-60%, at different strain rates up to 10 mm/min. Our results on piezoresistive, flexible pPDMS/CNT foams

  9. Experimental Surface Pressure Data Obtained on 65 deg Delta Wing Across Reynolds Number and Mach Number Ranges. Volume 2; Small-Radius Leading Edge

    Science.gov (United States)

    Chu, Julio; Luckring, James M.

    1996-01-01

    An experimental wind tunnel test of a 65 deg. delta wing model with interchangeable leading edges was conducted in the Langley National Transonic Facility (NTF). The objective was to investigate the effects of Reynolds and Mach numbers on slender-wing leading-edge vortex flows with four values of wing leading-edge bluntness. Experimentally obtained pressure data are presented without analysis in tabulated and graphical formats across a Reynolds number range of 6 x 10(exp 6) to 84 x 10(exp 6) at a Mach number of 0.85 and across a Mach number range of 0.4 to 0.9 at Reynolds numbers of 6 x 10(exp 6) and 60 x 10(exp 6). Normal-force and pitching-moment coefficient plots for these Reynolds number and Mach number ranges are also presented.

  10. 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

  11. 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...

  12. Characteristics of shock propagation in high-strength cement mortar

    Science.gov (United States)

    Wang, Zhanjiang; Li, Xiaolan; Zhang, Ruoqi

    2001-06-01

    Planar impact experiments have been performed on high-strength cement mortar to determine characteristics of shock propagation.The experiments were conducted on a light-gas gun,and permanent-magnet particle velocity gages were used to obtain the sand of 0.5 3.5mm size.A bulk density of 2.31g/cm^3,and a compressive and tensile strength of 82MPa and 7.8MPa,respectively,were determined.Three kinds of experimental techniques were used,including the reverse ballistic configuration.These techniques effectively averaged the measured dynamic compression state over a sensibly large volume of the test sample.The impact velocities were controlled over a range of approximately 80m/s to 0.83km/s.Hugoniot equation of state data were obtained for the material over a pressure range of approximately 0.2 2.0GPa,and its nonlinear constitutive relation were analyzed.The experiment results show that,in higher pressure range provided in the experiment,the shock wave in the material splits into two components of an elastic and a plastic,with the Hugoniot elastic limit 0.4 0.5GPa and the precursor velocity about 4.7km/s,and the material presents a very strong nonlinear dynamic response,and its shock amplitude will greatly decrease in propagation.

  13. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  14. Ultrafast Fiber Bragg Grating Interrogation for Sensing in Detonation and Shock Wave Experiments.

    Science.gov (United States)

    Rodriguez, George; Gilbertson, Steve M

    2017-01-27

    Chirped fiber Bragg grating (CFBG) sensors coupled to high speed interrogation systems are described as robust diagnostic approaches to monitoring shock wave and detonation front propagation tracking events for use in high energy density shock physics applications. Taking advantage of the linear distributed spatial encoding of the spectral band in single-mode CFBGs, embedded fiber systems and associated photonic interrogation methodologies are shown as an effective approach to sensing shock and detonation-driven loading processes along the CFBG length. Two approaches, one that detects spectral changes in the integrated spectrum of the CFBG and another coherent pulse interrogation approach that fully resolves its spectral response, shows that 100-MHz-1-GHz interrogation rates are possible with spatial resolution along the CFBG in the 50 µm to sub-millimeter range depending on the combination of CFBG parameters (i.e., length, chirp rate, spectrum) and interrogator design specifics. Results from several dynamic tests are used to demonstrate the performance of these high speed systems for shock and detonation propagation tracking under strong and weak shock pressure loading: (1) linear detonation front tracking in the plastic bonded explosive (PBX) PBX-9501; (2) tracking of radial decaying shock with crossover to non-destructive CFBG response; (3) shock wave tracking along an aluminum cylinder wall under weak loading accompanied by dynamic strain effects in the CFBG sensor.

  15. Physical Conditions in Shocked Interstellar Gas Interacting with the Supernova Remnant IC 443

    Science.gov (United States)

    Ritchey, Adam M.; Federman, Steven Robert; Jenkins, Edward B.; Caprioli, Damiano; Wallerstein, George

    2018-06-01

    We present the results of a detailed investigation into the physical conditions in interstellar material interacting with the supernova remnant IC 443. Our analysis is based on an examination of high-resolution HST/STIS spectra of two stars probing predominantly neutral gas located both ahead of and behind the supernova shock front. The pre-shock neutral gas is characterized by densities and temperatures typical of diffuse interstellar clouds, while the post-shock material exhibits a range of more extreme physical conditions, including high temperatures (>104 K) in some cases, which may require a sudden heating event to explain. The ionization level is enhanced in the high-temperature post-shock material, which could be the result of enhanced radiation from shocks or from an increase in cosmic-ray ionization. The gas-phase abundances of refractory elements are also enhanced in the high-pressure gas, suggesting efficient destruction of dust grains by shock sputtering. Observations of highly-ionized species at very high velocity indicate a post-shock temperature of 107 K for the hot X-ray emitting plasma of the remnant’s interior, in agreement with studies of thermal X-ray emission from IC 443.

  16. 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

  17. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    Science.gov (United States)

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-01

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ˜190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ˜920 GPa. The experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.

  18. 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.

  19. 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

  20. 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

  1. Micro-Raman spectroscopy of plagioclase and maskelynite in Martian meteorites: Evidence of progressive shock metamorphism

    OpenAIRE

    Fritz,Jorg; Greshake,Ansgar; Stoffler,Dieter

    2005-01-01

    We present the first systematic Micro-Raman spectroscopic investigation of plagioclase of different degree of shock metamorphism in Martian meteorites. The equilibrium shock pressure of all plagioclase phases of seventeen unpaired Martian meteorites was determined by measuring the shock-induced reduction of the refractive index. Systematic variations in the recorded Raman spectra of the plagioclase phases correlate with increasing shock pressure. In general, the shock induced deformation of t...

  2. Accuracy of the WatchBP office ABI device for office blood pressure measurement over a wide range of arm sizes.

    Science.gov (United States)

    Palatini, Paolo; Fania, Claudio; Gasparotti, Federica

    2018-04-01

    The aim of this study was to determine the accuracy of the WatchBP Office ABI monitor for office blood pressure measurement over a wide range of arm circumferences using the ANSI/AAMI/ISO 81060-2:2013 protocol. The device accuracy was tested in 88 participants whose mean±SD age was 54.5±17.6 years, whose arm circumference was 30.6±8.3 cm (range: 15-46 cm), and whose entry blood pressure (BP) was 138.3±23.4 mmHg for systolic and 83.7±14.6 mmHg for diastolic BP. Four cuffs (small, standard, large, and extra-large) suitable for arm circumferences ranging from 14.0 to 52.0 cm were used. The mean device-observer difference in the 264 separate BP data pairs was 0.7±3.8 mmHg for systolic BP and was 0.0±3.7 mmHg for diastolic BP. These data were in agreement with criterion 1 of the ANSI/AAMI/ISO 81060-2:2013 standard requirements (≤5±8 mmHg). Moreover, criterion 2 was satisfied, the mean±SD device-observer difference of the 88 participants being 0.7±3.1 and 0.0±3.2 mmHg, respectively, for systolic and diastolic BP. Good agreement between observer and device was present across the whole range of arm circumferences. These data show that the Microlife WatchBP Office ABI monitor satisfied the ANSI/AAMI/ISO 81060-2:2013 standard requirements across a wide range of arm sizes.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Using a gel/plastic surrogate to study the biomechanical response of the head under air shock loading: a combined experimental and numerical investigation.

    Science.gov (United States)

    Zhu, Feng; Wagner, Christina; Dal Cengio Leonardi, Alessandra; Jin, Xin; Vandevord, Pamela; Chou, Clifford; Yang, King H; King, Albert I

    2012-03-01

    A combined experimental and numerical study was conducted to determine a method to elucidate the biomechanical response of a head surrogate physical model under air shock loading. In the physical experiments, a gel-filled egg-shaped skull/brain surrogate was exposed to blast overpressure in a shock tube environment, and static pressures within the shock tube and the surrogate were recorded throughout the event. A numerical model of the shock tube was developed using the Eulerian approach and validated against experimental data. An arbitrary Lagrangian-Eulerian (ALE) fluid-structure coupling algorithm was then utilized to simulate the interaction of the shock wave and the head surrogate. After model validation, a comprehensive series of parametric studies was carried out on the egg-shaped surrogate FE model to assess the effect of several key factors, such as the elastic modulus of the shell, bulk modulus of the core, head orientation, and internal sensor location, on pressure and strain responses. Results indicate that increasing the elastic modulus of the shell within the range simulated in this study led to considerable rise of the overpressures. Varying the bulk modulus of the core from 0.5 to 2.0 GPa, the overpressure had an increase of 7.2%. The curvature of the surface facing the shock wave significantly affected both the peak positive and negative pressures. Simulations of the head surrogate with the blunt end facing the advancing shock front had a higher pressure compared to the simulations with the pointed end facing the shock front. The influence of an opening (possibly mimicking anatomical apertures) on the peak pressures was evaluated using a surrogate head with a hole on the shell of the blunt end. It was revealed that the presence of the opening had little influence on the positive pressures but could affect the negative pressure evidently.

  9. 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.

  10. 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.

  11. High-pressure {sup 3}He-Xe gas scintillators for simultaneous detection of neutrons and gamma rays over a large energy range

    Energy Technology Data Exchange (ETDEWEB)

    Tornow, W., E-mail: tornow@tunl.duke.edu [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Esterline, J.H. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Leckey, C.A. [Department of Physics, The College of William and Mary, Williamsburg, VA 23187 (United States); Weisel, G.J. [Department of Physics, Penn State Altoona, Altoona, PA 16601 (United States)

    2011-08-11

    We report on features of high-pressure {sup 3}He-Xe gas scintillators which have not been sufficiently addressed in the past. Such gas scintillators can be used not only for the efficient detection of low-energy neutrons but at the same time for the detection and identification of {gamma}-rays as well. Furthermore, {sup 3}He-Xe gas scintillators are also very convenient detectors for fast neutrons in the 1-10 MeV energy range and for high-energy {gamma}-rays in the 7-15 MeV energy range. Due to their linear pulse-height response and self calibration via the {sup 3}He(n,p){sup 3}H reaction, neutron and {gamma}-ray energies can easily be determined in this high-energy regime.

  12. High-pressure 3He-Xe gas scintillators for simultaneous detection of neutrons and gamma rays over a large energy range

    International Nuclear Information System (INIS)

    Tornow, W.; Esterline, J.H.; Leckey, C.A.; Weisel, G.J.

    2011-01-01

    We report on features of high-pressure 3 He-Xe gas scintillators which have not been sufficiently addressed in the past. Such gas scintillators can be used not only for the efficient detection of low-energy neutrons but at the same time for the detection and identification of γ-rays as well. Furthermore, 3 He-Xe gas scintillators are also very convenient detectors for fast neutrons in the 1-10 MeV energy range and for high-energy γ-rays in the 7-15 MeV energy range. Due to their linear pulse-height response and self calibration via the 3 He(n,p) 3 H reaction, neutron and γ-ray energies can easily be determined in this high-energy regime.

  13. Range of Motion and Plantar Pressure Evaluation for the Effects of Self-Care Foot Exercises on Diabetic Patients with and Without Neuropathy.

    Science.gov (United States)

    Cerrahoglu, Lale; Koşan, Umut; Sirin, Tuba Cerrahoglu; Ulusoy, Aslihan

    2016-05-01

    We aimed to investigate whether a home exercise for self-care program that consists of range of motion (ROM), stretching, and strengthening exercises could improve ROM for foot joints and plantar pressure distribution during walking in diabetic patients to prevent diabetic foot complications. Seventy-six diabetic patients were recruited (38 with neuropathy and 38 without neuropathy). Neuropathy and nonneuropathy groups were randomly divided into a home exercise group (n = 19) and a control group (n = 19). Exercise groups performed their own respective training programs for 4 weeks, whereas no training was done in the control group. Total contact area and plantar pressure under six foot areas before and after the exercise program were measured. Ankle and first metatarsophalangeal joint ROM were measured before and after the exercise program. In the exercise group, there were significant improvements in ROM for the ankle and first metatarsophalangeal joints (P .05). A home exercise program could be an effective preventive method for improving ROM for foot joints and plantar pressure distribution in diabetic patients independent of the presence of neuropathy.

  14. (p, ρ, T) Properties for n-butane in the temperature range from 280 K to 380 K at pressures up to 200 MPa

    International Nuclear Information System (INIS)

    Miyamoto, H.; Uematsu, M.

    2007-01-01

    The (p, ρ, T) properties for n-butane in the compressed liquid phase were measured by means of a metal-bellows variable volumometer in the temperature range from 280 K to 380 K at pressures up to 200 MPa. The mole fraction purity of the n-butane used in the measurements was 0.9997. The expanded uncertainties (k = 2) in temperature, pressure, and density measurements have been estimated to be less than ±3 mK; 1.4 kPa (p ≤ 7 MPa), 0.06% (7 MPa 150 MPa); and 0.09%, respectively. In the region above100 MPa at T = 280 K and T = 440 K, the uncertainty in density measurements increases from 0.09% to 0.13% and 0.22%, respectively. Eight (p, ρ, T) measurements at the same temperatures and pressures as the literature values have been conducted for comparisons. In addition, comparisons of the available equations of state with the present measurements are reported

  15. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    Energy Technology Data Exchange (ETDEWEB)

    Koukoulas, Triantafillos, E-mail: triantafillos.koukoulas@npl.co.uk; Piper, Ben [Acoustics Group, National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)

    2015-04-20

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  16. Bright emissive core-shell spherical microparticles for shock compression spectroscopy

    International Nuclear Information System (INIS)

    Christensen, James M.; Banishev, Alexandr A.; Dlott, Dana D.

    2014-01-01

    Experiments were performed to study the response to shock compression of rhodamine 6G (R6G) dye encapsulated in 1.25 μm diameter silica microspheres. When R6G was encapsulated in microspheres, the emission intensity under steady-state irradiation (the brightness) was 3.4 times greater than the same dye in solution (the free dye). At least part of the brightness improvement was caused by an enhanced radiative rate. When the microspheres were embedded in poly-methylmethacrylate subjected to planar shocks in the 3–8.4 GPa range by laser-driven flyer plates, the dye emission redshifted and lost intensity. The dye emission redshift represents an instantaneous response to changes in the local density. In free dye samples, the shock-induced intensity loss had considerably slower rise times and fall times than the redshift. When dye was encapsulated in microspheres, the time dependence of the intensity loss matched the redshift almost exactly over a range of shock pressures and durations. The faster response to shock of dye in silica microspheres was explained by dye photophysics. The microsphere environment decreased the singlet state lifetime, which decreased the rise time, and it also decreased the triplet state lifetime, which decreased the fall time. Since it is much easier and more convenient to make measurements of intensity rather than spectral shift, these microspheres represent a substantial improvement in optical sensors to monitor shock compression of microstructured materials.

  17. 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

  18. 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.

  19. Shock-induced microstructural response of mono- and nanocrystalline SiC ceramics

    Science.gov (United States)

    Branicio, Paulo S.; Zhang, Jingyun; Rino, José P.; Nakano, Aiichiro; Kalia, Rajiv K.; Vashishta, Priya

    2018-04-01

    The dynamic behavior of mono- and nanocrystalline SiC ceramics under plane shock loading is revealed using molecular-dynamics simulations. The generation of shock-induced elastic compression, plastic deformation, and structural phase transformation is characterized at different crystallographic directions as well as on a 5-nm grain size nanostructure at 10 K and 300 K. Shock profiles are calculated in a wide range of particle velocities 0.1-6.0 km/s. The predicted Hugoniot agree well with experimental data. Results indicate the generation of elastic waves for particle velocities below 0.8-1.9 km/s, depending on the crystallographic direction. In the intermediate range of particle velocities between 2 and 5 km/s, the shock wave splits into an elastic precursor and a zinc blende-to-rock salt structural transformation wave, which is triggered by shock pressure over the ˜90 GPa threshold value. A plastic wave, with a strong deformation twinning component, is generated ahead of the transformation wave for shocks in the velocity range between 1.5 and 3 km/s. For particle velocities greater than 5-6 km/s, a single overdriven transformation wave is generated. Surprisingly, shocks on the nanocrystalline sample reveal the absence of wave splitting, and elastic, plastic, and transformation wave components are seamlessly connected as the shock strength is continuously increased. The calculated strengths 15.2, 31.4, and 30.9 GPa for ⟨001⟩, ⟨111⟩, and ⟨110⟩ directions and 12.3 GPa for the nanocrystalline sample at the Hugoniot elastic limit are in excellent agreement with experimental data.

  20. 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.

  1. 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.

  2. Development of acoustically lined ejector technology for multitube jet noise suppressor nozzles by model and engine tests over a wide range of jet pressure ratios and temperatures

    Science.gov (United States)

    Atvars, J.; Paynter, G. C.; Walker, D. Q.; Wintermeyer, C. F.

    1974-01-01

    An experimental program comprising model nozzle and full-scale engine tests was undertaken to acquire parametric data for acoustically lined ejectors applied to primary jet noise suppression. Ejector lining design technology and acoustical scaling of lined ejector configurations were the major objectives. Ground static tests were run with a J-75 turbojet engine fitted with a 37-tube, area ratio 3.3 suppressor nozzle and two lengths of ejector shroud (L/D = 1 and 2). Seven ejector lining configurations were tested over the engine pressure ratio range of 1.40 to 2.40 with corresponding jet velocities between 305 and 610 M/sec. One-fourth scale model nozzles were tested over a pressure ratio range of 1.40 to 4.0 with jet total temperatures between ambient and 1088 K. Scaling of multielement nozzle ejector configurations was also studied using a single element of the nozzle array with identical ejector lengths and lining materials. Acoustic far field and near field data together with nozzle thrust performance and jet aerodynamic flow profiles are presented.

  3. Absolute Hugoniot measurements for CH foams in the 2-9 Mbar range

    Science.gov (United States)

    Aglitskiy, Y.; Velikovich, A. L.; Karasik, M.; Schmitt, A. J.; Serlin, V.; Weaver, J. L.; Oh, J.; Obenschain, S. P.; Cochrane, K. R.

    2018-03-01

    Absolute Hugoniot measurements for empty plastic foams at ˜10% of solid polystyrene density and supporting rad-hydro simulation results are reported. Planar foam slabs, ˜400 μm thick and ˜500 μm wide, some of which were covered with a 10 μm solid plastic ablator, were directly driven by 4 ns long Nike krypton-fluoride 248 nm wavelength laser pulses that produced strong shock waves in the foam. The shock and mass velocities in our experiments were up to 104 km/s and 84 km/s, respectively, and the shock pressures up to ˜9 Mbar. The motion of the shock and ablation fronts was recorded using side-on monochromatic x-ray imaging radiography. The steadiness of the observed shock and ablation fronts within ˜1% has been verified. The Hugoniot data inferred from our velocity measurements agree with the predictions of the SESAME and CALEOS equation-of-state models near the highest pressure ˜9 Mbar and density compression ratio ˜5. In the lower pressure range 2-5 Mbar, a lower shock density compression is observed than that predicted by the models. Possible causes for this discrepancy are discussed.

  4. Laser shock wave consolidation of nanodiamond powders on aluminum 319

    Energy Technology Data Exchange (ETDEWEB)

    Molian, Pal [Laboratory for Lasers, MEMS, and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)], E-mail: molian@iastate.edu; Molian, Raathai; Nair, Rajeev [Laboratory for Lasers, MEMS, and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)

    2009-01-01

    A novel coating approach, based on laser shock wave generation, was employed to induce compressive pressures up to 5 GPa and compact nanodiamond (ND) powders (4-8 nm) on aluminum 319 substrate. Raman scattering indicated that the coating consisted of amorphous carbon and nanocrystalline graphite with peaks at 1360 cm{sup -1} and 1600 cm{sup -1} respectively. Scanning electron microscopy revealed a wavy, non-uniform coating with an average thickness of 40 {mu}m and absence of thermal effect on the surrounding material. The phase transition from nanodiamond to other phases of carbon is responsible for the increased coating thickness. Vicker's microhardness test showed hardness in excess of 1000 kg{sub f}/mm{sup 2} (10 GPa) while nanoindentation test indicated much lower hardness in the range of 20 MPa to 2 GPa. Optical surface profilometry traces displayed slightly uneven surfaces compared to the bare aluminum with an average surface roughness (R{sub a}) in the range of 1.5-4 {mu}m depending on the shock wave pressure and type of confining medium. Ball-on-disc tribometer tests showed that the coefficient of friction and wear rate were substantially lower than the smoother, bare aluminum sample. Laser shock wave process has thus aided in the generation of a strong, wear resistant, durable carbon composite coating on aluminum 319 substrate.

  5. Time-resolved stereo PIV measurements of shock-boundary layer interaction on a supercritical airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Axel; Klaas, Michael; Schroeder, Wolfgang [RWTH Aachen University, Institute of Aerodynamics, Aachen (Germany)

    2012-03-15

    Time-resolved stereo particle-image velocimetry (TR-SPIV) and unsteady pressure measurements are used to analyze the unsteady flow over a supercritical DRA-2303 airfoil in transonic flow. The dynamic shock wave-boundary layer interaction is one of the most essential features of this unsteady flow causing a distinct oscillation of the flow field. Results from wind-tunnel experiments with a variation of the freestream Mach number at Reynolds numbers ranging from 2.55 to 2.79 x 10{sup 6} are analyzed regarding the origin and nature of the unsteady shock-boundary layer interaction. Therefore, the TR-SPIV results are analyzed for three buffet flows. One flow exhibits a sinusoidal streamwise oscillation of the shock wave only due to an acoustic feedback loop formed by the shock wave and the trailing-edge noise. The other two buffet flows have been intentionally influenced by an artificial acoustic source installed downstream of the test section to investigate the behavior of the interaction to upstream-propagating disturbances generated by a defined source of noise. The results show that such upstream-propagating disturbances could be identified to be responsible for the upstream displacement of the shock wave and that the feedback loop is formed by a pulsating separation of the boundary layer dependent on the shock position and the sound pressure level at the shock position. Thereby, the pulsation of the separation could be determined to be a reaction to the shock motion and not vice versa. (orig.)

  6. 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

  7. An Investigation of the Drag and Pressure Recovery of a Submerged Inlet and a Nose Inlet in the Transonic Flight Range with Free-fall Models

    Science.gov (United States)

    Selna, James; Schlaff, Bernard A

    1951-01-01

    The drag and pressure recovery of an NACA submerged-inlet model and an NACA series I nose-inlet model were investigated in the transonic flight range. The tests were conducted over a mass-flow-ratio range of 0.4 to 0.8 and a Mach number range of about 0.8 to 1.10 employing large-scale recoverable free-fall models. The results indicate that the Mach number of drag divergence of the inlet models was about the same as that of a basic model without inlets. The external drag coefficients of the nose-inlet model were less than those of the submerged-inlet model throughout the test range. The difference in drag coefficient based on the maximum cross-sectional area of the models was about 0.02 at supersonic speeds and about 0.015 at subsonic speeds. For a hypothetical airplane with a ratio of maximum fuselage cross-sectional area to wing area of 0.06, the difference in airplane drag coefficient would be relatively small, about 0.0012 at supersonic speeds and about 0.0009 at subsonic speeds. Additional drag comparisons between the two inlet models are made considering inlet incremental and additive drag.

  8. 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.

  9. 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

  10. Molten fuel/coolant interaction studies: some results obtained with the Windscale small shock tube rig

    International Nuclear Information System (INIS)

    Higham, E.J.; Vaughan, G.J.

    1978-02-01

    Experiments are described in which water has been brought into contact with various molten metals in a shock tube, thus simulating the fall of coolant into molten uranium dioxide in a postulated reactor accident. Impact velocities of the water on to the molten material were in the range 5 to 7 m/s. Shock-pulse pressures in the water column after impact and particle size distributions of the dispersed resolidified material that was recovered were measured. The proportion of dispersed material and the size of the shock pulse (by comparison with that expected from water hammer alone) have been used as criteria for the occurrence of a molten fuel/coolant interaction and such interactions of varying degrees of violence have been found for water/aluminium, water/bismuth, water/tin, over a range of temperatures from 350 0 C to 950 0 C, for water/boric oxide, but not for water/magnesium. (author)

  11. 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

  12. 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.

  13. Shock-induced borehole waves and fracture effects

    NARCIS (Netherlands)

    Fan, H.; Smeulders, D.M.J.

    2012-01-01

    We perform wave experiments using a vertical shock tube setup. Shock waves are generated by the rupture of a thin membrane. In the test section the incident pressure waves generate borehole-guided waves along water-saturated samples. The tube is equipped with side wall gages and a mobile pressure

  14. Relationship between energy deposition and shock wave phenomenon in an underwater electrical wire explosion

    Science.gov (United States)

    Han, Ruoyu; Zhou, Haibin; Wu, Jiawei; Qiu, Aici; Ding, Weidong; Zhang, Yongmin

    2017-09-01

    An experimental study of pressure waves generated by an exploding copper wire in a water medium is performed. We examined the effects of energy deposited at different stages on the characteristics of the resulting shock waves. In the experiments, a microsecond time-scale pulsed current source was used to explode a 300-μm-diameter, 4-cm-long copper wire with initial stored energies ranging from 500 to 2700 J. Our experimental results indicated that the peak pressure (4.5-8.1 MPa) and energy (49-287 J) of the shock waves did not follow a simple relationship with any electrical parameters, such as peak voltage or deposited energy. Conversely, the impulse had a quasi-linear relationship with the parameter Π. We also found that the peak pressure was mainly influenced by the energy deposited before separation of the shock wave front and the discharge plasma channel (DPC). The decay time constant of the pressure waveform was affected by the energy injection after the separation. These phenomena clearly demonstrated that the deposited energy influenced the expansion of the DPC and affected the shock wave characteristics.

  15. 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.

  16. Shock tube/time-of-flight mass spectrometer for high temperature kinetic studies

    International Nuclear Information System (INIS)

    Tranter, Robert S.; Giri, Binod R.; Kiefer, John H.

    2007-01-01

    A shock tube (ST) with online, time-of-flight mass spectrometric (TOF-MS) detection has been constructed for the study of elementary reactions at high temperature. The ST and TOF-MS are coupled by a differentially pumped molecular beam sampling interface, which ensures that the samples entering the TOF-MS are not contaminated by gases drawn from the cold end wall thermal boundary layer in the ST. Additionally, the interface allows a large range of postshock pressures to be used in the shock tube while maintaining high vacuum in the TOF-MS. The apparatus and the details of the sampling system are described along with an analysis in which cooling of the sampled gases and minimization of thermal boundary layer effects are discussed. The accuracy of kinetic measurements made with the apparatus has been tested by investigating the thermal unimolecular dissociation of cyclohexene to ethylene and 1,3-butadiene, a well characterized reaction for which considerable literature data that are in good agreement exist. The experiments were performed at nominal reflected shock wave pressures of 600 and 1300 Torr, and temperatures ranging from 1260 to 1430 K. The rate coefficients obtained are compared with the earlier shock tube studies and are found to be in very good agreement. As expected no significant difference is observed in the rate constant between pressures of 600 and 1300 Torr

  17. Decay of a laser generated shock wave in an aluminium target

    International Nuclear Information System (INIS)

    Werdiger, M.

    1993-09-01

    When a shock wave arrives at the near surface of a solid material, a radical and fast change occurs in the reflection properties of the material. The phenomenon is used in the present work in order to develop a new way to measure the transit time of a shock wave in a target. A 10 milliwatt He:Ne laser is directed toward the rear surface of the target. The reflected beam arrives at a photo-diode with a fast rise time of 150 psec which detects the instant of the change in the reflection. This technique, called 'continuous back lightning', is used in experiments with aluminium foil thickness in the range of 40μm ≤x≥ 1000μm. The shock wave is induced by a laser pulse of an intensity of 3*10 13 W/cm 2 . The results show two main physical regimes: in the first one 40μ ≤x≥ 210μm, there is a constant shock wave velocity which in our experiments was measured to be (12.81±0.67)km/s. In the second range of the thickness where 300μm there is a decay of the shock velocity. For x ≥ 210μm the geometry is one dimensional for our experimental conditions, while for x ≥ 300μm the 1-D geometry changes to 2 dimensional (2-D) geometry. The 2-D shock wave decay asymptotically (x→∞ to an acoustic wave. shock wave is described by a pressure scaling as x -n (n is a positive constant). The phenomenological equation of the state is taken to be P=A**u s + B*u s 2 +Bu s , where P is the pressure, u s - the shock velocity, A and B are constants. Applying our experimental results to the solution of the differential equation in this model A*x 2 ± B*x=C*x -n yields a value of n in the range 3.16 ≤n≥ 3.51. This pressure scaling law agrees with the self-similar solution of a concentrated impact on a surface between two media. This situation is well simulated by the laser deposition energy on a metal surface. In the experiment a 5% accuracy is achieved. Such a good accuracy has not been achieved so far in a laser induced shock-wave measurements in solids. (author). 52 refs

  18. 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.

  19. Simulation of long-range transport aerosols from the Asian Continent to Taiwan by a southward Asian high-pressure system.

    Science.gov (United States)

    Chuang, Ming-Tung; Fu, Joshua S; Jang, Carey J; Chan, Chang-Chuan; Ni, Pei-Cheng; Lee, Chung-Te

    2008-11-15

    Aerosol is frequently transported by a southward high-pressure system from the Asian Continent to Taiwan and had been recorded a 100% increase in mass level compared to non-event days from 2002 to 2005. During this time period, PM2.5 sulfate was found to increase as high as 155% on event days as compared to non-event days. In this study, Asian emission estimations, Taiwan Emission Database System (TEDS), and meteorological simulation results from the fifth-generation Mesoscale Model (MM5) were used as inputs for the Community Multiscale Air Quality (CMAQ) model to simulate a long-range transport of PM2.5 event in a southward high-pressure system from the Asian Continent to Taiwan. The simulation on aerosol mass level and the associated aerosol components were found within a reasonable accuracy. During the transport process, the percentage of semi-volatile PM2.5 organic carbon in PM2.5 plume only slightly decreased from 22-24% in Shanghai to 21% near Taiwan. However, the percentage of PM2.5 nitrate in PM2.5 decreased from 16-25% to 1%. In contrast, the percentage of PM2.5 sulfate in PM2.5 increased from 16-19% to 35%. It is interesting to note that the percentage of PM2.5 ammonium and PM2.5 elemental carbon in PM2.5 remained nearly constant. Simulation results revealed that transported pollutants dominate the air quality in Taipei when the southward high-pressure system moved to Taiwan. Such condition demonstrates the dynamic chemical transformation of pollutants during the transport process from continental origin over the sea area and to the downwind land.

  20. Experimental Studies of Sealing Mechanism of a Dismountable Microsystem-to-Macropart Fluidic Connector for High Pressure and a Wide Range of Temperature

    Directory of Open Access Journals (Sweden)

    Hugo Nguyen

    2010-01-01

    Full Text Available As fluidic microelectromechanical devices are developing and often attached to, or embedded in, large, complex, and expensive systems, the issues of modularity, maintenance, and subsystem replacement arise. In this work, a robust silicon connector suitable for high-pressure applications—likely with harsh fluids—in the temperature range of +100 to −100° C is demonstrated and tested together with a stainless steel nipple representing a simple and typical macropart. With a micromachined circular membrane equipped with a 5 μm high ridge, this connector is able to maintain a leak rate below 2.0×10−8 scc/s of gaseous helium with a pressure of up to 9.7 bar. Degradation of the sealing performance on reassembly is associated with the indentation of the ridge. However, the ridge makes the sealing interface less sensitive to particles in comparison with a flat reference. Most evaluation is made through the so-called heat-until-leak tests conducted to determine the maximum working temperature and the sealing mechanism of the connector. A couple of these are followed by cryogenic testing. The effect of thermal mismatch of the components is discussed and utilized as an early warning mechanism.

  1. Modelling flow and work hardening behaviour of cold worked Zr–2.5Nb pressure tube material in the temperature range of 30–600 oC

    International Nuclear Information System (INIS)

    Dureja, A.K.; Sinha, S.K.; Pawaskar, D.N.; Seshu, P.; Chakravartty, J.K.; Sinha, R.K.

    2014-01-01

    Under a postulated accident scenario of loss of cooling medium in an Indian Pressurised Heavy Water Reactor (IPHWR), temperature of the pressure tubes can rise and lead to large deformations. In order to investigate the modes of deformation of pressure tube – calandria tube assembly, material property data defining the flow behaviour over a temperature range from room temperature (RT) to 800 o C are needed. It is of practical importance to formulate mathematical equations to describe the stress–strain relationships of a material for a variety of reasons, such as the analysis of forming operations and the assessment of component's performance in service. A number of constitutive relations of empirical nature have been proposed and they have been found very suitable to describe the behaviour of a material. Although these relations are of empirical nature, various metallurgical factors appear to decide applicability of each of these relations. For example, grain size influences mainly the friction stress while the strain hardening is governed by dislocation density. In a recent work, tensile deformation behaviour of pressure tube material of IPHWR has been carried out over a range of temperature and strain rates (Dureja et al., 2011). It has been found that the strength parameters (yield and ultimate tensile strength) vary along the length of the tube with higher strength at the trailing end as compared to the leading end. This stems from cooling of the billet during the extrusion process which results in the variation of microstructure, texture and dislocation density from the leading to the trailing end. In addition, the variation in metallurgical parameters is also expected to influence the work hardening behaviour, which is known to control the plastic instability (related to uniform strain). In the present investigation, the tensile flow and work-hardening behaviour of a cold worked Zr–2.5Nb pressure tube material of IPHWRs has been studied over the

  2. 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...

  3. Influence of shock wave propagation on dielectric barrier discharge plasma actuator performance

    International Nuclear Information System (INIS)

    Erfani, Rasool; Zare-Behtash, Hossein; Kontis, Konstantinos

    2012-01-01

    Interest in plasma actuators as active flow control devices is growing rapidly due to their lack of mechanical parts, light weight and high response frequency. Although the flow induced by these actuators has received much attention, the effect that the external flow has on the performance of the actuator itself must also be considered, especially the influence of unsteady high-speed flows which are fast becoming a norm in the operating flight envelopes. The primary objective of this study is to examine the characteristics of a dielectric barrier discharge (DBD) plasma actuator when exposed to an unsteady flow generated by a shock tube. This type of flow, which is often used in different studies, contains a range of flow regimes from sudden pressure and density changes to relatively uniform high-speed flow regions. A small circular shock tube is employed along with the schlieren photography technique to visualize the flow. The voltage and current traces of the plasma actuator are monitored throughout, and using the well-established shock tube theory the change in the actuator characteristics are related to the physical processes which occur inside the shock tube. The results show that not only is the shear layer outside of the shock tube affected by the plasma but the passage of the shock front and high-speed flow behind it also greatly influences the properties of the plasma. (paper)

  4. Transonic buffet control research with two types of shock control bump based on RAE2822 airfoil

    Directory of Open Access Journals (Sweden)

    Yun TIAN

    2017-10-01

    Full Text Available Current research shows that the traditional shock control bump (SCB can weaken the intensity of shock and better the transonic buffet performance. The author finds that when SCB is placed downstream of the shock, it can decrease the adverse pressure gradient. This may prevent the shock foot separation bubble to merge with the trailing edge separation and finally improve the buffet performance. Based on RAE2822 airfoil, two types of SCB are designed according to the two different mechanisms. By using Reynolds-averaged Navier-Stokes (RANS and unsteady Reynolds-averaged Navier-Stokes (URANS methods to analyze the properties of RAE2822 airfoil with and without SCB, the results show that the downstream SCB can better the buffet performance under a wide range of freestream Mach number and the steady aerodynamics characteristic is similar to that of RAE2822 airfoil. The traditional SCB can only weaken the intensity of the shock under the design condition. Under the off-design conditions, the SCB does not do much to or even worsen the buffet performance. Indeed, the use of backward bump can flatten the leeward side of the airfoil, and this is similar to the mechanism that supercritical airfoil can weaken the recompression of shock wave.

  5. 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.

  6. Time-history of shock waves overrunning three-dimensional, cylindrical models

    International Nuclear Information System (INIS)

    Langheim, H.; Loeffler, E.

    To investigate the time-history of the Mach-stem of a shock wave overrunning a nuclear power plant shadowgraphs of threedimensional, cylindrical models with a globe cap were analysed. These models simulating the containment building differ only in the height of the cylinder. They were exposed with shock waves of shock strengths of 1.2 and 1.4, being equal to a peak reflexion overpressure of 0.45 resp. 1.0 bar. The time-histories of the Mach-stem differ only slightly. For this reason it can be stated that these time-histories are independent of the shock strength and the height of the cylinder in the prescribed range of the research program. In comparison with values given in the literature great differences were found at the rear side near the stagnation point of the globe cap resp. the stagnation line of the cylinder. The measured time for overrunning of the shock wave is the same as the time of arrival of the pressure-pulse at the interesting point of the model. This knowledge is a necessary premise for pressure-measurings from which the total load of structure can be determined. (orig.) [de

  7. Experimental and numerical investigations of shock wave propagation through a bifurcation

    Science.gov (United States)

    Marty, A.; Daniel, E.; Massoni, J.; Biamino, L.; Houas, L.; Leriche, D.; Jourdan, G.

    2018-02-01

    The propagation of a planar shock wave through a split channel is both experimentally and numerically studied. Experiments were conducted in a square cross-sectional shock tube having a main channel which splits into two symmetric secondary channels, for three different shock wave Mach numbers ranging from about 1.1 to 1.7. High-speed schlieren visualizations were used along with pressure measurements to analyze the main physical mechanisms that govern shock wave diffraction. It is shown that the flow behind the transmitted shock wave through the bifurcation resulted in a highly two-dimensional unsteady and non-uniform flow accompanied with significant pressure loss. In parallel, numerical simulations based on the solution of the Euler equations with a second-order Godunov scheme confirmed the experimental results with good agreement. Finally, a parametric study was carried out using numerical analysis where the angular displacement of the two channels that define the bifurcation was changed from 90° , 45° , 20° , and 0° . We found that the angular displacement does not significantly affect the overpressure experience in either of the two channels and that the area of the expansion region is the important variable affecting overpressure, the effect being, in the present case, a decrease of almost one half.

  8. 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

  9. 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

  10. 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.

  11. Experimental study of micro-shock tube flow

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ouk; Kim, Gyu Wan; Rasel, Md. Alim Iftakhar [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of); Kim, Heuy Dong [Fire Research Center, Korea Institute of Civil Engineering and Building Technology, Hwasung (Korea, Republic of)

    2015-03-15

    The flow characteristics in micro shock tube are investigated experimentally. Studies were carried out using a stainless steel micro shock tube. Shock and expansion wave was measured using 8 pressure sensors. The initial pressure ratio was varied from 4.3 to 30.5, and the diameter of tube was also changed from 3 mm to 6 mm. Diaphragm conditions were varied using two types of diaphragms. The results obtained show that the shock strength in the tube becomes stronger for an increase in the initial pressure ratio and diameter of tube. For the thinner diaphragm, the highest shock strength was found among varied diaphragm condition. Shock attenuation was highly influenced by the diameter of tube.

  12. Investigation of Surface Phenomena in Shocked Tin in Converging Geometry

    Energy Technology Data Exchange (ETDEWEB)

    Rousculp, Christopher L. [Los Alamos National Laboratory; Oro, David Michael [Los Alamos National Laboratory; Griego, Jeffrey Randall [Los Alamos National Laboratory; Turchi, Peter John [Los Alamos National Laboratory; Reinovsky, Robert Emil [Los Alamos National Laboratory; Bradley, Joseph Thomas [Los Alamos National Laboratory; Cheng, Baolian [Los Alamos National Laboratory; Freeman, Matthew Stouten [Los Alamos National Laboratory; Patten, Austin Randall [Los Alamos National Laboratory

    2016-03-21

    There is great interest in the behavior of the free surface of tin under shock loading. While it is known that meso-scale surface imperfections can seed the Richtmyer- Meshkov Instability (RMI) for a surface that is melted on release, much less is known about a tin surface that is solid, but plastically deforming. Here material properties such as shear and yield strength come into play especially in converging geometry. Previous experiments have been driven by direct contact HE. Usually a thin, flat target coupon is fielded with various single-mode, sinusoidal, machined, profiles on the free surface. The free surface is adjacent to either vacuum or an inert receiver gas. Most of these previous driver/target configurations have been nominal planer geometry. With modern HE it has been straightforward to shock tin into melt on release. However it has been challenging to achieve a low enough pressure for solid state on release. Here we propose to extend the existing base of knowledge to include the behavior of the free surface of tin in cylindrical converging geometry. By shock loading a cylindrical tin shell with a magnetically driven cylindrical liner impactor, the free surface evolution can be diagnosed with proton radiography. With the PHELIX capacitor bank, the drive can easily be varied to span the pressure range to achieve solid, mixed, and liquid states on release. A conceptual cylindrical liner and target is shown in Figure 1.

  13. Hugoniot measurements of double-shocked precompressed dense xenon plasmas

    Science.gov (United States)

    Zheng, J.; Chen, Q. F.; Gu, Y. J.; Chen, Z. Y.

    2012-12-01

    The current partially ionized plasmas models for xenon show substantial differences since the description of pressure and thermal ionization region becomes a formidable task, prompting the need for an improved understanding of dense xenon plasmas behavior at above 100 GPa. We performed double-shock compression experiments on dense xenon to determine accurately the Hugoniot up to 172 GPa using a time-resolved optical radiation method. The planar strong shock wave was produced using a flyer plate impactor accelerated up to ˜6 km/s with a two-stage light-gas gun. The time-resolved optical radiation histories were acquired by using a multiwavelength channel optical transience radiance pyrometer. Shock velocity was measured and mass velocity was determined by the impedance-matching methods. The experimental equation of state of dense xenon plasmas are compared with the self-consistent fluid variational calculations of dense xenon in the region of partial ionization over a wide range of pressures and temperatures.

  14. Role of heat shock transcription factor 1(HSF1)-upregulated macrophage in ameliorating pressure overload-induced heart failure in mice.

    Science.gov (United States)

    Du, Peizhao; Chang, Yaowei; Dai, Fangjie; Wei, Chunyan; Zhang, Qi; Li, Jiming

    2018-08-15

    In order to explore the role of macrophages in HSF1-mediated alleviation of heart failure, mice model of pressure overload-induced heart failure was established using transverse aortic constriction (TAC). Changes in cardiac function and morphology were studied in TAC and SHAM groups using ultrasonic device, tissue staining, electron microscopy, real-time quantitative polymerase chain reaction (RT-QPCR), and Western blotting. We found that mice in the TAC group showed evidence of impaired cardiac function and aggravation of fibrosis on ultrasonic and histopathological examination when compared to those in the SHAM group. The expressions of HSF1, LC3II/LC3I, Becline-1 and HIF-1, as well as autophagosome formation in TAC group were greater than that in SHAM group. On sub-group analyses in the TAC group, improved cardiac function and alleviation of fibrosis was observed in the HSF1 TG subgroup as compared to that in the wild type subgroup. Expressions of LC3II/LC3I, Becline-1 and HIF-1, too showed an obvious increase; and increased autophagosome formation was observed on electron microscopy. Opposite results were observed in the HSF1 KO subgroup. These results collectively suggest that in the pressure overload heart failure model, HSF1 promoted formation of macrophages by inducing upregulation of HIF-1 expression, through which heart failure was ameliorated. Copyright © 2018 Elsevier B.V. All rights reserved.

  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. 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.

  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. Thin Foil Acceleration Method for Measuring the Unloading Isentropes of Shock-Compressed Matter

    International Nuclear Information System (INIS)

    Asay, J.R.; Chhabildas, L.C.; Fortov, V.E.; Kanel, G.I.; Khishchenko, K.V.; Lomonosov, I.V.; Mehlhorn, T.; Razorenov, S.V.; Utkin, A.V.

    1999-01-01

    This work has been performed as part of the search for possible ways to utilize the capabilities of laser and particle beams techniques in shock wave and equation of state physics. The peculiarity of these techniques is that we have to deal with micron-thick targets and not well reproducible incident shock wave parameters, so all measurements should be of a high resolution and be done in one shot. Besides the Hugoniots, the experimental basis for creating the equations of state includes isentropes corresponding to unloading of shock-compressed matter. Experimental isentrope data are most important in the region of vaporization. With guns or explosive facilities, the unloading isentrope is recovered from a series of experiments where the shock wave parameters in plates of standard low-impedance materials placed behind the sample are measured [1,2]. The specific internal energy and specific volume are calculated from the measured p(u) release curve which corresponds to the Riemann integral. This way is not quite suitable for experiments with beam techniques where the incident shock waves are not well reproducible. The thick foil method [3] provides a few experimental points on the isentrope in one shot. When a higher shock impedance foil is placed on the surface of the material studied, the release phase occurs by steps, whose durations correspond to that for the shock wave to go back and forth in the foil. The velocity during the different steps, connected with the knowledge of the Hugoniot of the foil, allows us to determine a few points on the isentropic unloading curve. However, the method becomes insensitive when the low pressure range of vaporization is reached in the course of the unloading. The isentrope in this region can be measured by recording the smooth acceleration of a thin witness plate foil. With the mass of the foil known, measurements of the foil acceleration will give us the vapor pressure

  19. 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

  20. 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..pressure is maximum, at M the velocity of the gas U/sub 1/, minus xi, equals the speed of sound C, at M' there is a linear relationship between U/sub 1/, dU/sub 1//dt and C. The representative curve of the compressed gas passed analytically through all of them. The relative position of P, M, M' leads to three solutions of the quadratic conservation equations. Representative curves of the state of the imploded gas, at various values of ..gamma.., are shown.

  1. 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.

  2. Understanding the shock and detonation response of high explosives at the continuum and meso scales

    Science.gov (United States)

    Handley, C. A.; Lambourn, B. D.; Whitworth, N. J.; James, H. R.; Belfield, W. J.

    2018-03-01

    The shock and detonation response of high explosives has been an active research topic for more than a century. In recent years, high quality data from experiments using embedded gauges and other diagnostic techniques have inspired the development of a range of new high-fidelity computer models for explosives. The experiments and models have led to new insights, both at the continuum scale applicable to most shock and detonation experiments, and at the mesoscale relevant to hotspots and burning within explosive microstructures. This article reviews the continuum and mesoscale models, and their application to explosive phenomena, gaining insights to aid future model development and improved understanding of the physics of shock initiation and detonation propagation. In particular, it is argued that "desensitization" and the effect of porosity on high explosives can both be explained by the combined effect of thermodynamics and hydrodynamics, rather than the traditional hotspot-based explanations linked to pressure-dependent reaction rates.

  3. Laser-generated shock-wave experiments in metals above 1 TPa

    International Nuclear Information System (INIS)

    Trainor, R.J.; Shaner, J.W.; Auerbach, J.M.; Phillion, D.W.

    1978-01-01

    Some initial experiments are described which form part of a new program aimed at significantly extending the range of high pressures and densities which may be explored in laboratory equation-of-state (EOS) experiments. These experiments will utilize high-energy lasers, such as those employed in the Laser Fusion Program at Lawrence Livermore Laboratory (LLL), to generate intense shock waves in materials of interest

  4. Thermophysical properties of multi-shock compressed dense argon.

    Science.gov (United States)

    Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  5. 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.

  6. 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

  7. Experimental particle acceleration by water evaporation induced by shock waves

    Science.gov (United States)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial

  8. 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

  9. Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

    Science.gov (United States)

    Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2018-05-01

    Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

  10. Potential change in flaw geometry of an initially shallow finite-length surface flaw during a pressurized-thermal-shock transient

    International Nuclear Information System (INIS)

    Shum, D.K.; Bryson, J.W.; Merkle, J.G.

    1993-09-01

    This study presents preliminary estimates on whether an shallow, axially oriented, inner-surface finite-length flaw in a PWR-RPV would tend to elongate in the axial direction and/or deepen into the wall of the vessel during a postulated PTS transient. Analysis results obtained based on the assumptions of (1) linear-elastic material response, and (2) cladding with same toughness as the base metal, indicate that a nearly semicircular flaw would likely propagate in the axial direction followed by propagation into the wall of the vessel. Note that these results correspond to initiation within the lower-shelf fracture toughness temperature range, and that their general validity within the lower-transition temperature range remains to be determined. The sensitivity of the numerical results aid conclusions to the following analysis assumptions are evaluated: (1) reference flaw geometry along the entire crack front and especially within the cladding region; (2) linear-elastic vs elastic-plastic description of material response; and (3) base-material-only vs bimaterial cladding-base vessel-model assumption. The sensitivity evaluation indicates that the analysis results are very sensitive to the above assumptions

  11. Shock resistance of composite material pipes

    International Nuclear Information System (INIS)

    Pays, M.F.

    1995-01-01

    Composite materials have found a wide range of applications for EDF nuclear plants. Applications include fire pipework, demineralized water, service water, and emergency-supplied service water piping. Some of those pipework is classified nuclear safety, their integrity (resistance to water aging and earthquakes or accidental excess pressure (water hammer)) must be safeguarded. As composite materials generally suffer damage for low energy impacts (under 10 J), the pipes planned for the Civaux power plant have been studied for their resistance to a low speed shock (0 to 50 m/s) and of a 0 to 110 J energy level. For three representative diameters (20, 150, 600 mm), the minimum impact energy that leads to a leak has been determined to be respectively 18, 20 and 48 J. Then the leak rate versus impact energy was plotted; until roughly 90 J, the leak rate remains stable at less than 25 cm 3 /h and raises to higher values (300 cm 3 /h) afterwards. The level of leakage in the range of impact energy tested always stays within the limits set by the Safety Authorities for metallic pipes. These results have been linked to destructive examinations, to clarify the damage mechanisms. Other tests are still ongoing to follow the evolution of the damage and of the leak rate while the pipe is maintained under service pressure during one year

  12. 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.

  13. 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.)

  14. Microjetting from a grooved Al surface under supported and unsupported shocks

    Science.gov (United States)

    Shao, Jian-Li; Wang, Pei; He, An-Min

    2014-08-01

    Using molecular dynamics methods, we simulate and compare the microjetting from a grooved Al surface induced by supported and unsupported shocks at different breakout pressures. Via the analysis on the microjetting morphologies and mass distributions, we find that the threshold of shock breakout pressure for the microjetting formation is almost same, but the variation of microjet mass with shock pressure shows a great difference for the two loading patterns. Under supported shock loading, the microjet mass keeps a continuous increase with increasing shock pressure, and release melting can enhance it markedly. By contrast, the microjet mass under unsupported shocks is smaller and seems no remarkable increase with shock pressure in our simulations (at extremely short pulses), implying the shock decaying can weaken the microjetting. Of course, a large area of fragments near the surface may form in this case. The microjet source distributions corresponding to supported and unsupported shocks are presented. It is found that the former becomes apparently broader than the latter with increasing shock pressure. Besides, the microjet tip velocity under supported shocks may appear a reduction because of the material strength effect below release melting. While under unsupported shocks, all the microjets in solid and melted states will experience the reduction of tip velocity. These decrements of tip velocity can be fitted by an exponential function.

  15. A cryogenic multichannel electronically scanned pressure module

    Science.gov (United States)

    Shams, Qamar A.; Fox, Robert L.; Adcock, Edward E.; Kahng, Seun K.

    1992-01-01

    Consideration is given to a cryogenic multichannel electronically scanned pressure (ESP) module developed and tested over an extended temperature span from -184 to +50 C and a pressure range of 0 to 5 psig. The ESP module consists of 32 pressure sensor dice, four analog 8 differential-input multiplexers, and an amplifier circuit, all of which are packaged in a physical volume of 2 x 1 x 5/8 in with 32 pressure and two reference ports. Maximum nonrepeatability is measured at 0.21 percent of full-scale output. The ESP modules have performed consistently well over 15 times over the above temperature range and continue to work without any sign of degradation. These sensors are also immune to repeated thermal shock tests over a temperature change of 220 C/sec.

  16. 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.

  17. 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.

  18. Triaxial behaviour of a micro-concrete complete stress-strain curves for confining pressures ranging from 0 to 100 MPa

    International Nuclear Information System (INIS)

    Jamet, P.; Millard, A.; Nahas, G.

    1984-05-01

    A series of triaxial tests has been performed on micro-concrete cylinders. The specimens have been strained with a constant displacement rate, up to a deformation of about 10%. Two different domains were distinguihed. For low confining pressures strain softening is observed, the behaviour of the material becomes ductile for high confining pressures. Continuous measurement of the volume of fluid which had to be injected or withdrawn from the cell, to keep the confining pressure constant during the test, allowed to obtain data, concerning the overall lateral deformations of the specimens. Some specimens were also subjected to successive loadings with different confining pressures, in order to study the influence of stress path

  19. 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.

  20. 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)