Response of basic structural elements and B-52 structural components to simulated nuclear overpressure. Volume II-program data (basic structural elements). Final report, 1 June 1977-30 September 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syring, R.P.; Grubb, R.L.

1979-09-30

This document reports on the following: (1) experimental determination of the response of 16 basic structural elements and 7 B-52 components to simulated nuclear overpressure environments (utilizing Sandia Corporation's Thunderpipe Shock Tube), (2) analysis of these test specimens utilizing the NOVA-2 computer program, and (3) correlation of test and analysis results.

Approximating a free-field blast environment in the test section of an explosively driven conical shock tube

NASA Astrophysics Data System (ADS)

Stewart, J. B.

2018-02-01

This paper presents experimental data on incident overpressures and the corresponding impulses obtained in the test section of an explosively driven 10° (full angle) conical shock tube. Due to the shock tube's steel walls approximating the boundary conditions seen by a spherical sector cut out of a detonating sphere of energetic material, a 5.3-g pentolite shock tube driver charge produces peak overpressures corresponding to a free-field detonation from an 816-g sphere of pentolite. The four test section geometries investigated in this paper (open air, cylindrical, 10° inscribed square frustum, and 10° circumscribed square frustum) provide a variety of different time histories for the incident overpressures and impulses, with a circumscribed square frustum yielding the best approximation of the estimated blast environment that would have been produced by a free-field detonation.

Lateral spread of sonic boom measurements from US Air Force boomfile flight tests

NASA Technical Reports Server (NTRS)

Downing, J. Micah

1992-01-01

A series of sonic boom flight tests were conducted by the US Air Force at Edwards AFB in 1987 with current supersonic DOD aircraft. These tests involved 43 flights by various aircraft at different Mach number and altitude combinations. The measured peak overpressures to predicted values as a function of lateral distance are compared. Some of the flights are combined into five groups because of the varying profiles and the limited number of sonic booms obtained during this study. The peak overpressures and the lateral distances are normalized with respect to the Carlson method predicted centerline overpressures and lateral cutoff distances, respectively, to facilitate comparisons between sonic boom data from similar flight profiles. It is demonstrated that the data agrees with sonic boom theory and previous studies and adds to the existing sonic boom database by including sonic boom signatures, tracking, and weather data in a digital format.

Response of basic structural elements and B-52 structural components to simulated nuclear overpressure. Volume I-program description and results (basic structural elements). Final report, 1 June 1977-30 September 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syring, R.P.; Grubb, R.L.

1979-09-30

This document reports on the following: (1) experimental determination of the response of 16 basic structural elements and 7 B-52 components to simulated nuclear overpressure environments (utilizing Sandia Corporation's Thunderpipe Shock Tube), (2) analysis of these test specimens utilizing the NOVA-2 computer program, and (3) correlation of test and analysis results.

Evolution of overpressured and underpressured oil and gas reservoirs, Anadarko Basin of Oklahoma, Texas, and Kansas

USGS Publications Warehouse

Nelson, Phillip H.; Gianoutsos, Nicholas J.

2011-01-01

Departures of resistivity logs from a normal compaction gradient indicate that overpressure previously extended north of the present-day overpressured zone. These indicators of paleopressure, which are strongest in the deep basin, are mapped to the Kansas-Oklahoma border in shales of Desmoinesian age. The broad area of paleopressure has contracted to the deep basin, and today the overpressured deep basin, as determined from drillstem tests, is bounded on the north by strata with near normal pressures (hydrostatic), grading to the northwest to pressures that are less than hydrostatic (underpressured). Thus the pressure regime in the northwest portion of the Anadarko Basin has evolved from paleo-overpressure to present-day underpressure. Using pressure data from drillstem tests, we constructed cross sections and potentiometric maps that illustrate the extent and nature of present-day underpressuring. Downcutting and exposure of Lower Permian and Pennsylvanian strata along, and east of, the Nemaha fault zone in central Oklahoma form the discharge locus where pressure reaches near atmospheric. From east to west, hydraulic head increases by several hundred feet in each rock formation, whereas elevation increases by thousands of feet. The resulting underpressuring of the aquifer-supported oil and gas fields, which also increases from east to west, is a consequence of the vertical separation between surface elevation and hydraulic head. A 1,000-ft thick cap of Permian evaporites and shales isolates the underlying strata from the surface, preventing re-establishment of a normal hydrostatic gradient. Thus, the present-day pressure regime of oil and gas reservoirs, overpressured in the deep basin and underpressured on the northwest flank of the basin, is the result of two distinct geologic events-rapid burial and uplift/erosion-widely separated in time.

Subsurface fluid pressures from drill-stem tests, Uinta Basin, Utah

USGS Publications Warehouse

Nelson, P.H.

2002-01-01

High fluid pressures are known to be associated with oil and gas fields in the Uinta Basin, Utah. Shut-in pressure measurements from drill-stem tests show how pressure varies with depth and by area within the basin. The data base used in this report incorporates over 2,000 pressure measurements from drill-stem tests in wells completed prior to 1985. However, the number of useful pressure measurements is considerably less, because many drill-stem tests fail to stabilize at the actual formation pressure if the permeability is low. By extracting the maximum pressure measurements recorded in a collection of wells within an area, the trend of formation pressure within that area can be approximated. Areal compilations of pressures from drill-stem tests show that overpressured rock formations occur throughout much of the northern and eastern areas of the Uinta Basin. In particular, significant overpressuring (0.5 < pressure gradient < 0.8 psi/ft) is found throughout much of the Altamont-Bluebell field at depths ranging from 10,000 to 13,000 ft, equivalent to 5,000 to 8,000 ft below sea level. Limited data indicate that the pressure gradient declines at depths greater than 13,000 ft. An underpressured zone appears to exist in the Altamont-Bluebell field at depths shallower than 5,000 ft. Throughout the eastern Uinta Basin, moderately overpressured zones (0.46 < pressure gradient < 0.5 psi/ft) are common, with local evidence of significantly overpressured zones, but pressure gradients greater than 0.6 psi/ft are rare.

Reliability of Measurement of Glenohumeral Internal Rotation, External Rotation, and Total Arc of Motion in 3 Test Positions

PubMed Central

Kevern, Mark A.; Beecher, Michael; Rao, Smita

2014-01-01

Context: Athletes who participate in throwing and racket sports consistently demonstrate adaptive changes in glenohumeral-joint internal and external rotation in the dominant arm. Measurements of these motions have demonstrated excellent intrarater and poor interrater reliability. Objective: To determine intrarater reliability, interrater reliability, and standard error of measurement for shoulder internal rotation, external rotation, and total arc of motion using an inclinometer in 3 testing procedures in National Collegiate Athletic Association Division I baseball and softball athletes. Design: Cross-sectional study. Setting: Athletic department. Patients or Other Participants Thirty-eight players participated in the study. Shoulder internal rotation, external rotation, and total arc of motion were measured by 2 investigators in 3 test positions. The standard supine position was compared with a side-lying test position, as well as a supine test position without examiner overpressure. Results: Excellent intrarater reliability was noted for all 3 test positions and ranges of motion, with intraclass correlation coefficient values ranging from 0.93 to 0.99. Results for interrater reliability were less favorable. Reliability for internal rotation was highest in the side-lying position (0.68) and reliability for external rotation and total arc was highest in the supine-without-overpressure position (0.774 and 0.713, respectively). The supine-with-overpressure position yielded the lowest interrater reliability results in all positions. The side-lying position had the most consistent results, with very little variation among intraclass correlation coefficient values for the various test positions. Conclusions: The results of our study clearly indicate that the side-lying test procedure is of equal or greater value than the traditional supine-with-overpressure method. PMID:25188316

Improved Overpressure Recording and Modeling for Near-Surface Explosion Forensics

NASA Astrophysics Data System (ADS)

Kim, K.; Schnurr, J.; Garces, M. A.; Rodgers, A. J.

2017-12-01

The accurate recording and analysis of air-blast acoustic waveforms is a key component of the forensic analysis of explosive events. Smartphone apps can enhance traditional technologies by providing scalable, cost-effective ubiquitous sensor solutions for monitoring blasts, undeclared activities, and inaccessible facilities. During a series of near-surface chemical high explosive tests, iPhone 6's running the RedVox infrasound recorder app were co-located with high-fidelity Hyperion overpressure sensors, allowing for direct comparison of the resolution and frequency content of the devices. Data from the traditional sensors is used to characterize blast signatures and to determine relative iPhone microphone amplitude and phase responses. A Wiener filter based source deconvolution method is applied, using a parameterized source function estimated from traditional overpressure sensor data, to estimate system responses. In addition, progress on a new parameterized air-blast model is presented. The model is based on the analysis of a large set of overpressure waveforms from several surface explosion test series. An appropriate functional form with parameters determined empirically from modern air-blast and acoustic data will allow for better parameterization of signals and the improved characterization of explosive sources.

EFFECTS OF OVERPRESSURES IN GROUP SHELTERS ON ANIMALS AND DUMMIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, J.E.; White, C.S.; Chiffelle, T.L.

1953-09-01

S>Relative biological hazards of blast were studied in two types of communal air-raid shelters during Shots 1 and 8. Dogs, restrained within the shelters during detonation, were studied pathologically and clinically for blast injuries. Two anthropometric dummies were test objects for displacement studies utilizing high-speed photography. Physical data included pressure vs time and air-drag determinations. During Shot 1, animals sustained marked blast damages (hemorrhages in lungs and abdominal organs), three dogs were ataxic. and the dummies were rather violently displaced. In Shot 8, however, no significant injuries were found in the animals, and the dummies were minimally displaced. Analysis ofmore » the physical data indicated that blast injuries and violent displacements may occur at much lower static overpressures than previously assumed from conventional explosion data. Furthermore, biological damage appeared to be related to the rate of rise of the overpressure and air drag, as well as the maximum overpressure values. (auth)« less

Preliminary results from the White Sands Missile Range sonic boom propagation experiment

NASA Technical Reports Server (NTRS)

Willshire, William L., Jr.; Devilbiss, David W.

1992-01-01

Sonic boom bow shock amplitude and rise time statistics from a recent sonic boom propagation experiment are presented. Distributions of bow shock overpressure and rise time measured under different atmospheric turbulence conditions for the same test aircraft are quite different. The peak overpressure distributions are skewed positively, indicating a tendency for positive deviations from the mean to be larger than negative deviations. Standard deviations of overpressure distributions measured under moderate turbulence were 40 percent larger than those measured under low turbulence. As turbulence increased, the difference between the median and the mean increased, indicating increased positive overpressure deviations. The effect of turbulence was more readily seen in the rise time distributions. Under moderate turbulence conditions, the rise time distribution means were larger by a factor of 4 and the standard deviations were larger by a factor of 3 from the low turbulence values. These distribution changes resulted in a transition from a peaked appearance of the rise time distribution for the morning to a flattened appearance for the afternoon rise time distributions. The sonic boom propagation experiment consisted of flying three types of aircraft supersonically over a ground-based microphone array with concurrent measurements of turbulence and other meteorological data. The test aircraft were a T-38, an F-15, and an F-111, and they were flown at speeds of Mach 1.2 to 1.3, 30,000 feet above a 16 element, linear microphone array with an inter-element spacing of 200 ft. In two weeks of testing, 57 supersonic passes of the test aircraft were flown from early morning to late afternoon.

Pretest analysis document for Test S-FS-7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, D.G.

This report documents the pretest calculations completed for Semiscale Test S-FS-7. This test will simulate a transient initiated by a 14.3% break in a steam generator bottom feedwater line downstream of the check valve. The initial conditions represent normal operating conditions for a C-E System 80 nuclear power plant. Predictions of transients resulting from feedwater line breaks in these plants have indicated that significant primary system overpressurization may occur. The results of a RELAP5/MOD2/CY21 code calculation indicate that the test objectives for Test S-FS-7 can be achieved. The primary system overpressurization will occur but pose no threat to personnel ormore » to plant integrity. 3 refs., 15 figs., 5 tabs.« less

Pretest analysis document for Test S-FS-11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, D.G.; Shaw, R.A.

This report documents the pretest calculations completed for Semiscale Test S-FS-11. This test will simulate a transient initiated by a 50% break in a steam generator bottom feedwater line downstream of the check valve. The initial conditions represents normal operating conditions for a C-E System 80 nuclear plant. Prediction of transients resulting from feedwater line breaks in these plants have indicated that significant primary system overpressurization may occur. The results of a RELAP5/MOD2/CY21 code calculation indicate that the test objectives for Test S-FS-11 can be achieved. The primary system overpressurization will occur but pose no threat to personnel or plantmore » integrity. 3 refs., 15 figs., 5 tabs.« less

Characterization of the Scale Model Acoustic Test Overpressure Environment using Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Nielsen, Tanner; West, Jeff

2015-01-01

The Scale Model Acoustic Test (SMAT) is a 5% scale test of the Space Launch System (SLS), which is currently being designed at Marshall Space Flight Center (MSFC). The purpose of this test is to characterize and understand a variety of acoustic phenomena that occur during the early portions of lift off, one being the overpressure environment that develops shortly after booster ignition. The pressure waves that propagate from the mobile launcher (ML) exhaust hole are defined as the ignition overpressure (IOP), while the portion of the pressure waves that exit the duct or trench are the duct overpressure (DOP). Distinguishing the IOP and DOP in scale model test data has been difficult in past experiences and in early SMAT results, due to the effects of scaling the geometry. The speed of sound of the air and combustion gas constituents is not scaled, and therefore the SMAT pressure waves propagate at approximately the same speed as occurs in full scale. However, the SMAT geometry is twenty times smaller, allowing the pressure waves to move down the exhaust hole, through the trench and duct, and impact the vehicle model much faster than occurs at full scale. The DOP waves impact portions of the vehicle at the same time as the IOP waves, making it difficult to distinguish the different waves and fully understand the data. To better understand the SMAT data, a computational fluid dynamics (CFD) analysis was performed with a fictitious geometry that isolates the IOP and DOP. The upper and lower portions of the domain were segregated to accomplish the isolation in such a way that the flow physics were not significantly altered. The Loci/CHEM CFD software program was used to perform this analysis.

Measurement and Simulation of Low Frequency Impulse Noise and Ground Vibration from Airblasts

NASA Astrophysics Data System (ADS)

Hole, L. R.; Kaynia, A. M.; Madshus, C.

1998-07-01

This paper presents numerical simulations of low frequency ground vibration and dynamic overpressure in air using two different numerical models. Analysis is based on actual recordings during blast tests at Haslemoen test site in Norway in June 1994. It is attempted to use the collected airblast-induced overpressures and ground vibrations in order to asses the applicability of the two models. The first model is a computer code which is based on a global representation of ground and atmospheric layers, a so-called Fast Field Program (FFP). A viscoelastic and a poroelastic version of this model is used. The second model is a two-dimensionalmoving-loadformulation for the propagation of airblast over ground. The poroelastic FFP gives the most complete and realistic reproduction of the processes involved, including decay of peak overpressure amplitude and dominant frequency of signals with range. It turns out that themoving-loadformulation does not provide a complete description of the physics involved when the speed of sound in air is different from the ground wavespeeds.

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

PubMed Central

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

2012-01-01

The loading conditions used in some current in vivo and in vitro blast-induced neurotrauma models may not be representative of real-world blast conditions. To address these limitations, we developed a compressed-gas driven shock tube with different driven lengths that can generate Friedlander-type blasts. The shock tube can generate overpressures up to 650 kPa with durations between 0.3 and 1.1 ms using compressed helium driver gas, and peak overpressures up to 450 kPa with durations between 0.6 and 3 ms using compressed nitrogen. This device is used for short-duration blast overpressure loading for small animal in vivo injury models, and contrasts the more frequently used long duration/high impulse blast overpressures in the literature. We also developed a new apparatus that is used with the shock tube to recreate the in vivo intracranial overpressure response for loading in vitro culture preparations. The receiver device surrounds the culture with materials of similar impedance to facilitate the propagation of a single overpressure pulse through the tissue. This method prevents pressure waves reflecting off the tissue that can cause unrealistic deformation and injury. The receiver performance was characterized using the longest helium-driven shock tube, and produced in-fluid overpressures up to 1500 kPa at the location where a culture would be placed. This response was well correlated with the overpressure conditions from the shock tube (R2 = 0.97). Finite element models of the shock tube and receiver were developed and validated to better elucidate the mechanics of this methodology. A demonstration exposing a culture to the loading conditions created by this system suggest tissue strains less than 5% for all pressure levels simulated, which was well below functional deficit thresholds for strain rates less than 50 s−1. This novel system is not limited to a specific type of culture model and can be modified to reproduce more complex pressure pulses. PMID:22470367

Pretest analysis document for Test S-FS-6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaw, R.A.; Hall, D.G.

This report documents the pretest analyses completed for Semiscale Test S-FS-6. This test will simulate a transient initiated by a 100% break in a steam generator bottom feedwater line downstream of the check valve. The initial conditions represent normal operating conditions for a C-E System 80 nuclear power plant. Predictions of transients resulting from feedwater line breaks in these plants have indicated that significant primary system overpressurization may occur. The enclosed analyses include a RELAP5/MOD2/CY21 code calculation and preliminary results from a facility hot, integrated test which was conducted to near S-FS-6 specifications. The results of these analyses indicate thatmore » the test objectives for Test S-FS-6 can be achieved. The primary system overpressurization will pose no threat to personnel or plant integrity.« less

Posttest analysis of the 1:6-scale reinforced concrete containment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pfeiffer, P.A.; Kennedy, J.M.; Marchertas, A.H.

A prediction of the response of the Sandia National Laboratories 1:6- scale reinforced concrete containment model test was made by Argonne National Laboratory. ANL along with nine other organizations performed a detailed nonlinear response analysis of the 1:6-scale model containment subjected to overpressurization in the fall of 1986. The two-dimensional code TEMP-STRESS and the three-dimensional NEPTUNE code were utilized (1) to predict the global response of the structure, (2) to identify global failure sites and the corresponding failure pressures and (3) to identify some local failure sites and pressure levels. A series of axisymmetric models was studied with the two-dimensionalmore » computer program TEMP-STRESS. The comparison of these pretest computations with test data from the containment model has provided a test for the capability of the respective finite element codes to predict global failure modes, and hence serves as a validation of these codes. Only the two-dimensional analyses will be discussed in this paper. 3 refs., 10 figs.« less

Validation and Simulation of ARES I Scale Model Acoustic Test -1- Pathfinder Development

NASA Technical Reports Server (NTRS)

Putnam, G. C.

2011-01-01

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. To take advantage of this data, a digital representation of the ASMAT test setup has been constructed and test firings of the motor have been simulated using the Loci/CHEM computational fluid dynamics software. Within this first of a series of papers, results from ASMAT simulations with the rocket in a held down configuration and without water suppression have then been compared to acoustic data collected from similar live-fire tests to assess the accuracy of the simulations. Detailed evaluations of the mesh features, mesh length scales relative to acoustic signals, Courant-Friedrichs-Lewy numbers, and spatial residual sources have been performed to support this assessment. Results of acoustic comparisons have shown good correlation with the amplitude and temporal shape of pressure features and reasonable spectral accuracy up to approximately 1000 Hz. Major plume and acoustic features have been well captured including the plume shock structure, the igniter pulse transient, and the ignition overpressure. Finally, acoustic propagation patterns illustrated a previously unconsidered issue of tower placement inline with the high intensity overpressure propagation path.

Inverse modeling of the overpressure distribution in an extension fracture with an arbitrary aperture variation: application to non-feeder dikes in the Miyake-jima Volcano, Japan

NASA Astrophysics Data System (ADS)

Kusumoto, Shigekazu; Geshi, Nobuo; Gudmundsson, Agust

2010-05-01

We derived a solution for the overpressure distribution acting on the walls (surfaces) of an extension fracture (a hydrofracture) with an arbitrary opening-displacement (or aperture) variation. In the proposed model, we assume that the overpressure distribution can be described by Fourier cosine series. We at first present a solution for the forward model giving the fracture aperture when it is opened by an irregular overpressure variation obtained using the Fourier cosine series. Next, by changing the form of the solution for the forward model, we obtain a matrix equation that can be used to estimate the Fourier coefficients to obtain the overpressure distribution from the fracture aperture variation. As simple examples of this inverse analysis, we estimate the overpressure conditions from crack apertures given analytically for two cases, namely, 1) the overpressure in the crack is constant, and 2) the overpressure variation in the crack varies linearly from its center. The estimated overpressure distributions were found to be correct, although a small 'noise' was present. Since the method presented here gives the overpressure distribution as a Fourier series by the aperture data measured at a finite number of points, the overpressure conditions for forming the fracture can be determined for each wavelength. The Fourier coefficient of n = 0 is an important coefficient that gives the average value of the overpressure acting inside the crack. With the exception of n = 0, the Fourier coefficient of n = 1 expresses the longest wavelength component of the irregular overpressure. Thus, because this coefficient including the coefficient of n = 0 gives the longest wavelength component in the irregular overpressure, the component may be an important indicator of the overpressure condition that decides the basic form of the crack. We applied the solution for the inverse analysis to the thickness data of 19 non-feeder dikes exposed in the caldera wall of the Miyake-jima Volcano, Japan. In the analysis, the host-rock Young's modulus and Poisson's ratio were taken as 1 GPa and 0.25. The results show that most of the estimated overpressures increase toward the tips of the dikes and reach about 5 to 15 MPa (average was 8 MPa). In addition, results indicate host-rock fracture toughnesses between 60 MPa m1-2 and 170 MPa m1-2 (average 100 MPa m1-2). For comparison, we also estimated the magma overpressure by the least square method, assuming constant overpressure. This method gives overpressure between 1.5 MPa and 4 MPa (average 2.8 MPa). Similarly, the fracture toughnesses estimated in this way range between 30 MPa m1-2 and 120 MPa m1-2 (average 55 MPa m1-2). These methods and assumptions thus yield somewhat different results, as expected, but indicate the likely ranges of the magma overpressures and host-rock fracture toughnesses both of which are very reasonable and agree with earlier results obtained by different methods.

Blast from pressurized carbon dioxide released into a vented atmospheric chamber

NASA Astrophysics Data System (ADS)

Hansen, P. M.; Gaathaug, A. V.; Bjerketvedt, D.; Vaagsaether, K.

2018-03-01

This study describes the blast from pressurized carbon dioxide (CO2) released from a high-pressure reservoir into an openly vented atmospheric chamber. Small-scale experiments with pure vapor and liquid/vapor mixtures were conducted and compared with simulations. A motivation was to investigate the effects of vent size and liquid content on the peak overpressure and impulse response in the atmospheric chamber. The comparison of vapor-phase CO2 test results with simulations showed good agreement. This numerical code described single-phase gas dynamics inside a closed chamber, but did not model any phase transitions. Hence, the simulations described a vapor-only test into an unvented chamber. Nevertheless, the simulations reproduced the incident shock wave, the shock reflections, and the jet release inside the atmospheric chamber. The rapid phase transition did not contribute to the initial shock strength in the current test geometry. The evaporation rate was too low to contribute to the measured peak overpressure that was in the range of 15-20 kPa. The simulation results produced a calculated peak overpressure of 12 kPa. The liquid tests showed a significantly higher impulse compared to tests with pure vapor. Reducing the vent opening from 0.1 to 0.01 m2 resulted in a slightly higher impulse calculated at 100 ms. The influence of the vent area on the calculated impulse was significant in the vapor-phase tests, but not so clear in the liquid/vapor mixture tests.

Potential for deep basin-centered gas accumulation in Hanna Basin, Wyoming

USGS Publications Warehouse

Wilson, Michael S.; Dyman, Thaddeus S.; Nuccio, Vito F.

2001-01-01

The potential for a continuous-type basin-centered gas accumulation in the Hanna Basin in Carbon County, Wyoming, is evaluated using geologic and production data including mud-weight, hydrocarbon-show, formation-test, bottom-hole-temperature, and vitrinite reflectance data from 29 exploratory wells. This limited data set supports the presence of a hypothetical basin-centered gas play in the Hanna Basin. Two generalized structural cross sections illustrate our interpretations of possible abnormally pressured compartments. Data indicate that a gas-charged, overpressured interval may occur within the Cretaceous Mowry, Frontier, and Niobrara Formations at depths below 10,000 ft along the southern and western margins of the basin. Overpressuring may also occur near the basin center within the Steele Shale and lower Mesaverde Group section at depths below 18,000 to 20,000 ft. However, the deepest wells drilled to date (12,000 to 15,300 ft) have not encountered over-pressure in the basin center. This overpressured zone is likely to be relatively small (probably 20 to 25 miles in diameter) and is probably depleted of gas near major basement reverse faults and outcrops where gas may have escaped. Water may have invaded reservoirs through outcrops and fracture zones along the basin margins, creating an extensive normally pressured zone. A zone of subnormal pressure also may exist below the water-saturated, normal-pressure zone and above the central zone of overpressure. Subnormal pressures have been interpreted in the center of the Hanna Basin at depths ranging from 10,000 to 25,000 ft based on indirect evidence including lost-circulation zones. Three wells on the south side of the basin, where the top of the subnormally pressured zone is interpreted to cut across stratigraphic boundaries, tested the Niobrara Formation and recovered gas and oil shows with very low shut-in pressures.

Fluid involvement in normal faulting

NASA Astrophysics Data System (ADS)

Sibson, Richard H.

2000-04-01

Evidence of fluid interaction with normal faults comes from their varied role as flow barriers or conduits in hydrocarbon basins and as hosting structures for hydrothermal mineralisation, and from fault-rock assemblages in exhumed footwalls of steep active normal faults and metamorphic core complexes. These last suggest involvement of predominantly aqueous fluids over a broad depth range, with implications for fault shear resistance and the mechanics of normal fault reactivation. A general downwards progression in fault rock assemblages (high-level breccia-gouge (often clay-rich) → cataclasites → phyllonites → mylonite → mylonitic gneiss with the onset of greenschist phyllonites occurring near the base of the seismogenic crust) is inferred for normal fault zones developed in quartzo-feldspathic continental crust. Fluid inclusion studies in hydrothermal veining from some footwall assemblages suggest a transition from hydrostatic to suprahydrostatic fluid pressures over the depth range 3-5 km, with some evidence for near-lithostatic to hydrostatic pressure cycling towards the base of the seismogenic zone in the phyllonitic assemblages. Development of fault-fracture meshes through mixed-mode brittle failure in rock-masses with strong competence layering is promoted by low effective stress in the absence of thoroughgoing cohesionless faults that are favourably oriented for reactivation. Meshes may develop around normal faults in the near-surface under hydrostatic fluid pressures to depths determined by rock tensile strength, and at greater depths in overpressured portions of normal fault zones and at stress heterogeneities, especially dilational jogs. Overpressures localised within developing normal fault zones also determine the extent to which they may reutilise existing discontinuities (for example, low-angle thrust faults). Brittle failure mode plots demonstrate that reactivation of existing low-angle faults under vertical σ1 trajectories is only likely if fluid overpressures are localised within the fault zone and the surrounding rock retains significant tensile strength. Migrating pore fluids interact both statically and dynamically with normal faults. Static effects include consideration of the relative permeability of the faults with respect to the country rock, and juxtaposition effects which determine whether a fault is transmissive to flow or acts as an impermeable barrier. Strong directional permeability is expected in the subhorizontal σ2 direction parallel to intersections between minor faults, extension fractures, and stylolites. Three dynamic mechanisms tied to the seismic stress cycle may contribute to fluid redistribution: (i) cycling of mean stress coupled to shear stress, sometimes leading to postfailure expulsion of fluid from vertical fractures; (ii) suction pump action at dilational fault jogs; and, (iii) fault-valve action when a normal fault transects a seal capping either uniformly overpressured crust or overpressures localised to the immediate vicinity of the fault zone at depth. The combination of σ2 directional permeability with fluid redistribution from mean stress cycling may lead to hydraulic communication along strike, contributing to the protracted earthquake sequences that characterise normal fault systems.

Nonlinear oscillations and collapse of elongated bubbles subject to weak viscous effects: Effect of internal overpressure

NASA Astrophysics Data System (ADS)

Tsiglifis, Kostas; Pelekasis, Nikos A.

2007-07-01

The details of nonlinear oscillations and collapse of elongated bubbles, subject to large internal overpressure, are studied by a boundary integral method. Weak viscous effects on the liquid side are accounted for by integrating the equations of motion across the boundary layer that is formed adjacent to the interface. For relatively large bubbles with initial radius R0 on the order of millimeters, PSt=PSt'/(2σ/R0)˜300 and Oh =μ/(σR0ρ)1/2˜200, and an almost spherical initial shape, S˜1, Rayleigh-Taylor instability prevails and the bubble breaks up as a result of growth of higher modes and the development of regions of very small radius of curvature; σ, ρ, μ, and PSt' denote the surface tension, density, viscosity, and dimensional static pressure in the host liquid while S is the ratio between the length of the minor semiaxis of the bubble, taken as an axisymmetric ellipsoid, and its equivalent radius R0. For finite initial elongations, 0.5⩽S <1, the bubble collapses either via two jets that counterpropagate along the axis of symmetry and eventually coalesce at the equatorial plane, or in the form of a sink flow approaching the center of the bubble along the equatorial plane. This pattern persists for the above range of initial elongations examined and large internal overpressure amplitudes, ɛB⩾1, irrespective of Oh. It is largely due to the phase in the growth of the second Legendre mode during the after-bounce of the oscillating bubble, during which it acquires large enough positive accelerations for collapse to take place. For smaller bubbles with initial radius on the order of micrometers, PSt˜4 and Oh ˜20, and small initial elongations, 0.75

Numerical modeling of porosity waves in the Nankai accretionary wedge décollement, Japan: implications for aseismic slip

NASA Astrophysics Data System (ADS)

Joshi, Ajit; Appold, Martin S.

2017-01-01

Seismic and hydrologic observations of the Nankai accretionary wedge décollement, Japan, show that overpressures at depths greater than ˜2 km beneath the seafloor could have increased to near lithostatic values due to sediment compaction and diagenesis, clay dehydration, and shearing. The resultant high overpressures are hypothesized then to have migrated in rapid surges or pulses called `porosity waves' up the dip of the décollement. Such high velocities—much higher than expected Darcy fluxes—are possible for porosity waves if the porous media through which the waves travel are deformable enough for porosity and permeability to increase strongly with increasing fluid pressure. The present study aimed to test the hypothesis that porosity waves can travel at rates (kilometers per day) fast enough to cause aseismic slip in the Nankai décollement. The hypothesis was tested using a one-dimensional numerical solution to the fluid mass conservation equation for elastic porous media. Results show that porosity waves generated at depths of ˜2 km from overpressures in excess of lithostatic pressure can propagate at rates sufficient to account for aseismic slip along the décollement over a wide range of hydrogeological conditions. Sensitivity analysis showed porosity wave velocity to be strongly dependent on specific storage, fluid viscosity, and the permeability-depth gradient. Overpressure slightly less than lithostatic pressure could also produce porosity waves capable of traveling at velocities sufficient to cause aseismic slip, provided that hydrogeologic properties of the décollement are near the limits of their geologically reasonable ranges.

Shuttle Orbiter Atmospheric Revitalization Pressure Control Subsystem

NASA Technical Reports Server (NTRS)

Walleshauser, J. J.; Ord, G. R.; Prince, R. N.

1982-01-01

The Atmospheric Revitalization Pressure Control Subsystem (ARPCS) provides oxygen partial pressure and total pressure control for the habitable atmosphere of the Shuttle for either a one atmosphere environment or an emergency 8 PSIA mode. It consists of a Supply Panel, Control Panel, Cabin Pressure Relief Valves and Electronic Controllers. The panels control and monitor the oxygen and nitrogen supplies. The cabin pressure relief valves protect the habitable environment from overpressurization. Electronic controllers provide proper mixing of the two gases. This paper describes the ARPCS, addresses the changes in hardware that have occurred since the inception of the program; the performance of this subsystem during STS-1 and STS-2; and discusses future operation modes.

Attenuation of blast pressure behind ballistic protective vests.

PubMed

Wood, Garrett W; Panzer, Matthew B; Shridharani, Jay K; Matthews, Kyle A; Capehart, Bruce P; Myers, Barry S; Bass, Cameron R

2013-02-01

Clinical studies increasingly report brain injury and not pulmonary injury following blast exposures, despite the increased frequency of exposure to explosive devices. The goal of this study was to determine the effect of personal body armour use on the potential for primary blast injury and to determine the risk of brain and pulmonary injury following a blast and its impact on the clinical care of patients with a history of blast exposure. A shock tube was used to generate blast overpressures on soft ballistic protective vests (NIJ Level-2) and hard protective vests (NIJ Level-4) while overpressure was recorded behind the vest. Both types of vest were found to significantly decrease pulmonary injury risk following a blast for a wide range of conditions. At the highest tested blast overpressure, the soft vest decreased the behind armour overpressure by a factor of 14.2, and the hard vest decreased behind armour overpressure by a factor of 56.8. Addition of body armour increased the 50th percentile pulmonary death tolerance of both vests to higher levels than the 50th percentile for brain injury. These results suggest that ballistic protective body armour vests, especially hard body armour plates, provide substantial chest protection in primary blasts and explain the increased frequency of head injuries, without the presence of pulmonary injuries, in protected subjects reporting a history of blast exposure. These results suggest increased clinical suspicion for mild to severe brain injury is warranted in persons wearing body armour exposed to a blast with or without pulmonary injury.

A study of sonic boom overpressure trends with respect to weight, altitude, Mach number, and vehicle shaping

NASA Technical Reports Server (NTRS)

Needleman, Kathy E.; Mack, Robert J.

1990-01-01

This paper presents and discusses trends in nose shock overpressure generated by two conceptual Mach 2.0 configurations. One configuration was designed for high aerodynamic efficiency, while the other was designed to produce a low boom, shaped-overpressure signature. Aerodynamic lift, sonic boom minimization, and Mach-sliced/area-rule codes were used to analyze and compute the sonic boom characteristics of both configurations with respect to cruise Mach number, weight, and altitude. The influence of these parameters on the overpressure and the overpressure trends are discussed and conclusions are given.

On the Interaction and Coalescence if Spherical Blast Waves

NASA Technical Reports Server (NTRS)

Kandula, Max; Freeman, Robert J.

2005-01-01

The scaling and similarity laws concerning the propagation of isolated spherical blast waves are briefly reviewed. Both point source explosions and high pressure gas explosions are considered. Test data on blast overpressure from the interaction and coalescence of spherical blast waves emanating from explosives in the form of shaped charges of different strength placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure. The results point out the possibility of detecting source explosions from far-field pressure measurements.

Combustion dynamics in liquid rocket engines

NASA Technical Reports Server (NTRS)

Mclain, W. H.

1971-01-01

A chemical analysis of the emission and absorption spectra in the combustion chamber of a nitrogen tetroxide/aerozine-50 rocket engine was conducted. Measurements were made under conditions of preignition, ignition, and post combustion operating periods. The cause of severe ignition overpressures sporadically observed during the vacuum startup of the Apollo reaction control system engine was investigated. The extent to which residual propellants or condensed intermediate reaction products remain after the engine has been operated in a pulse mode duty cycle was determined.

Analysis on the overpressure characterization with respect to depositional environment facies: Case Study in Miri Area, Baram Delta

NASA Astrophysics Data System (ADS)

Mhd Hanapiah, N.; Yusoff, W. I. Wan; Zakariah, M. N. A.

2017-10-01

Overpressure studies in oil and gas exploration and production are carried out in order to mitigate any losses that could happen while drilling. These concerns can be addressed by enhancing the understanding of overpressure characterization in the fields. This research emphasizes in determining the pore pressure trend in Miri area to assist pore pressure prediction for future hydrocarbon exploration and production. Generally, pore pressure trends are related to mechanisms that contribute to the overpressure generation. In the region predominant overpressure are disequilibrium compaction within the prodelta shales meanwhile in outer shelf overpressure generation controlled by fluid expansion in deltaic sequence of inner shelf area. The objective of this research is to analyze the pore pressure profile of wells for determining vertical trends of pore pressure for various depositional environment facies of Miri area. Integration of rock physics and pore pressure analysis and relating the trends to environment depositional environment facies within shale underlying sand interval. Analysis done shows that overpressure top is characterize by depositional environment facies within shale underlying sand interval.

The formation and evolution of reconnection-driven, slow-mode shocks in a partially ionised plasma

NASA Astrophysics Data System (ADS)

Hillier, A.; Takasao, S.; Nakamura, N.

2016-06-01

The role of slow-mode magnetohydrodynamic (MHD) shocks in magnetic reconnection is of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, we use numerical simulations to investigate the role of collisional coupling between a proton-electron, charge-neutral fluid and a neutral hydrogen fluid for the one-dimensional (1D) Riemann problem initiated in a constant pressure and density background state by a discontinuity in the magnetic field. This system, in the MHD limit, is characterised by two waves. The first is a fast-mode rarefaction wave that drives a flow towards a slow-mode MHD shock wave. The system evolves through four stages: initiation, weak coupling, intermediate coupling, and a quasi-steady state. The initial stages are characterised by an over-pressured neutral region that expands with characteristics of a blast wave. In the later stages, the system tends towards a self-similar solution where the main drift velocity is concentrated in the thin region of the shock front. Because of the nature of the system, the neutral fluid is overpressured by the shock when compared to a purely hydrodynamic shock, which results in the neutral fluid expanding to form the shock precursor. Once it has formed, the thickness of the shock front is proportional to ξ I-1.2 , which is a smaller exponent than would be naively expected from simple scaling arguments. One interesting result is that the shock front is a continuous transition of the physical variables of subsonic velocity upstream of the shock front (a c-shock) to a sharp jump in the physical variables followed by a relaxation to the downstream values for supersonic upstream velocity (a j-shock). The frictional heating that results from the velocity drift across the shock front can amount to ~2 per cent of the reference magnetic energy.

Eye-Directed Overpressure Airwave-Induced Trauma Causes Lasting Damage to the Anterior and Posterior Globe: A Model for Testing Cell-Based Therapies

PubMed Central

Bricker-Anthony, Courtney; Hines-Beard, Jessica

2016-01-01

Abstract Purpose: Characterization of the response of the Balb/c mouse to an eye-directed overpressure airwave, with the hypothesis that this mouse strain and model is useful for testing potential therapeutics for the treatment of traumatic eye injury. Methods: The left eyes of adult Balb/c mice were exposed to an eye-directed overpressure airwave. Intraocular pressure (IOP) was measured and eyes were inspected for gross pathology changes. Optical coherence tomography and histology were used to examine the structural integrity of the retina and optic nerve. Immunohistochemistry, in vivo molecular fluorophores, and a multiplex enzyme-linked immunosorbent assay were utilized to identify changes in cell death, neuroinflammation, and oxidative stress. Results: This model induced a transient increase in IOP, corneal injuries, infrequent large retinal detachments, retinal pigment epithelium (RPE) vacuolization, glial reactivity, and retinal cell death. Both the corneal damage and RPE vacuolization persisted with time. Optic nerve degeneration occurred as early as 7 days postinjury and persisted out to 60 days. Retinal cell death, increased levels of reactive oxygen species, and neuroinflammation were detected at 7 days postinjury. Conclusions: The injury profile of the Balb/c mouse is consistent with commonly observed pathologies in blast-exposed patients. The damage is throughout the eye and persistent, making this mouse model useful for testing cell-based therapies. PMID:26982447

Experimental study of near-field entrainment of moderately overpressured jets

USGS Publications Warehouse

Solovitz, S.A.; Mastin, L.G.; Saffaraval, F.

2011-01-01

Particle image velocimetry (PIV) experiments have been conducted to study the velocity flow fields in the developing flow region of high-speed jets. These velocity distributions were examined to determine the entrained mass flow over a range of geometric and flow conditions, including overpressured cases up to an overpressure ratio of 2.83. In the region near the jet exit, all measured flows exhibited the same entrainment up until the location of the first shock when overpressured. Beyond this location, the entrainment was reduced with increasing overpressure ratio, falling to approximately 60 of the magnitudes seen when subsonic. Since entrainment ratios based on lower speed, subsonic results are typically used in one-dimensional volcanological models of plume development, the current analytical methods will underestimate the likelihood of column collapse. In addition, the concept of the entrainment ratio normalization is examined in detail, as several key assumptions in this methodology do not apply when overpressured.

Overpressures in the Uinta Basin, Utah: Analysis using a three-dimensional basin evolution model

NASA Astrophysics Data System (ADS)

McPherson, Brian J. O. L.; Bredehoeft, John D.

2001-04-01

High pore fluid pressures, approaching lithostatic, are observed in the deepest sections of the Uinta basin, Utah. Geologic observations and previous modeling studies suggest that the most likely cause of observed overpressures is hydrocarbon generation. We studied Uinta overpressures by developing and applying a three-dimensional, numerical model of the evolution of the basin. The model was developed from a public domain computer code, with addition of a new mesh generator that builds the basin through time, coupling the structural, thermal, and hydrodynamic evolution. Also included in the model are in situ hydrocarbon generation and multiphase migration. The modeling study affirmed oil generation as an overpressure mechanism, but also elucidated the relative roles of multiphase fluid interaction, oil density and viscosity, and sedimentary compaction. An important result is that overpressures by oil generation create conditions for rock fracturing, and associated fracture permeability may regulate or control the propensity to maintain overpressures.

Simulation of Acoustics for Ares I Scale Model Acoustic Tests

NASA Technical Reports Server (NTRS)

Putnam, Gabriel; Strutzenberg, Louise L.

2011-01-01

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity acoustic measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. To take advantage of this data, a digital representation of the ASMAT test setup has been constructed and test firings of the motor have been simulated using the Loci/CHEM computational fluid dynamics software. Results from ASMAT simulations with the rocket in both held down and elevated configurations, as well as with and without water suppression have been compared to acoustic data collected from similar live-fire tests. Results of acoustic comparisons have shown good correlation with the amplitude and temporal shape of pressure features and reasonable spectral accuracy up to approximately 1000 Hz. Major plume and acoustic features have been well captured including the plume shock structure, the igniter pulse transient, and the ignition overpressure.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, K. B.; Brown, C. G.; May, M. J.

2014-09-15

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, K. B.; Brown, C. G.; May, M. J.

2014-09-01

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

Explosive Characteristics of Carbonaceous Nanoparticles

NASA Astrophysics Data System (ADS)

Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

2013-03-01

Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V1/3 (dp/pt)max ~ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ~ 101 -102 g/m3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ~ 200 bar-m/s, placing it borderline St-1/St-2. Work supported through the NIOSH Nanotechnology Research Center (NTRC)

Rupture threshold characterization of polymer-shelled ultrasound contrast agents subjected to static overpressure

NASA Astrophysics Data System (ADS)

Chitnis, Parag V.; Lee, Paul; Mamou, Jonathan; Allen, John S.; Böhmer, Marcel; Ketterling, Jeffrey A.

2011-04-01

Polymer-shelled micro-bubbles are employed as ultrasound contrast agents (UCAs) and vesicles for targeted drug delivery. UCA-based delivery of the therapeutic payload relies on ultrasound-induced shell rupture. The fragility of two polymer-shelled UCAs manufactured by Point Biomedical or Philips Research was investigated by characterizing their response to static overpressure. The nominal diameters of Point and Philips UCAs were 3 μm and 2 μm, respectively. The UCAs were subjected to static overpressure in a glycerol-filled test chamber with a microscope-reticule lid. UCAs were reconstituted in 0.1 mL of water and added over the glycerol surface in contact with the reticule. A video-microscope imaged UCAs as glycerol was injected (5 mL/h) to vary the pressure from 2 to 180 kPa over 1 h. Neither UCA population responded to overpressure until the rupture threshold was exceeded, which resulted in abrupt destruction. The rupture data for both UCAs indicated three subclasses that exhibited different rupture behavior, although their mean diameters were not statistically different. The rupture pressures provided a measure of UCA fragility; the Philips UCAs were more resilient than Point UCAs. Results were compared to theoretical models of spherical shells under compression. Observed variations in rupture pressures are attributed to shell imperfections. These results may provide means to optimize polymeric UCAs for drug delivery and elucidate associated mechanisms.

Analysis of MINIE2013 Explosion Air-Blast Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schnurr, Julie M.; Rodgers, Arthur J.; Kim, Keehoon

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

On the Propagation and Interaction of Spherical Blast Waves

NASA Technical Reports Server (NTRS)

Kandula, Max; Freeman, Robert

2007-01-01

The characteristics and the scaling laws of isolated spherical blast waves have been briefly reviewed. Both self-similar solutions and numerical solutions of isolated blast waves are discussed. Blast profiles in the near-field (strong shock region) and the far-field (weak shock region) are examined. Particular attention is directed at the blast overpressure and shock propagating speed. Consideration is also given to the interaction of spherical blast waves. Test data for the propagation and interaction of spherical blast waves emanating from explosives placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure.

49 CFR Appendix B to Part 178 - Alternative Leakproofness Test Methods

Code of Federal Regulations, 2013 CFR

2013-10-01

... closed, and placed in a testing chamber. The testing chamber must be evacuated down to a pressure of 5 kPa which equals an over-pressure inside the packaging of 95 kPa. The air in the testing chamber must...(d) of this subchapter. A packaging passes the test if there is no leakage of helium. (2) Pressure...

49 CFR Appendix B to Part 178 - Alternative Leakproofness Test Methods

Code of Federal Regulations, 2014 CFR

2014-10-01

... closed, and placed in a testing chamber. The testing chamber must be evacuated down to a pressure of 5 kPa which equals an over-pressure inside the packaging of 95 kPa. The air in the testing chamber must...(d) of this subchapter. A packaging passes the test if there is no leakage of helium. (2) Pressure...

49 CFR Appendix B to Part 178 - Alternative Leakproofness Test Methods

Code of Federal Regulations, 2012 CFR

2012-10-01

... closed, and placed in a testing chamber. The testing chamber must be evacuated down to a pressure of 5 kPa which equals an over-pressure inside the packaging of 95 kPa. The air in the testing chamber must...(d) of this subchapter. A packaging passes the test if there is no leakage of helium. (2) Pressure...

49 CFR Appendix B to Part 178 - Alternative Leakproofness Test Methods

Code of Federal Regulations, 2011 CFR

2011-10-01

... closed, and placed in a testing chamber. The testing chamber must be evacuated down to a pressure of 5 kPa which equals an over-pressure inside the packaging of 95 kPa. The air in the testing chamber must...(d) of this subchapter. A packaging passes the test if there is no leakage of helium. (2) Pressure...

Thermal and pressure histories of the Malay Basin, offshore Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yusoff, W.I.; Swarbrick, R.E.

1994-07-01

The Malay Basin is a Neogene intracratonic basin characterized by high heat flow and rapid sedimentation; moderate to high overpressure is common in deeper reservoirs. Thermal conductivity and temperature data from 55 wells have been used to reassess the areal and vertical heat-flow distribution within the basin. Anomalously high temperatures have been observed in some sandstone intervals above the overpressured reservoir section. A narrow to rather abrupt pressure transition zone could be recognized. All hydrocarbon-filled reservoirs seemed to be associated with high heat flow (i.e., about 90 mW/m[sup 2]). Overpressure in some wells is approaching critical fracture pressure (i.e., 0.85more » psi/ft. pressure gradient) in the region. In the central part of the basin, the overpressured sections are found within the shallower (<2000 m) hydrocarbon-bearing units. Selective studies of the temporal development of the pore pressure indicated that overpressure development is associated with episodes of rapid sedimentation. A preliminary fluid flow model supported by pressure modeling is proposed whereby hot fluids are currently being expelled from deeper overpressured sandstone and mudrocks through a fractured seal induced by overpressure. The latter is caused by relatively rapid burial since late Tertiary times. Hydrocarbon migration may have been aided by this fluid movement.« less

Sonic-boom measurements in the focus region during the ascent of Apollo 17. [maximum positive overpressure, positive impulse, signature duration, and bow-shock rise time

NASA Technical Reports Server (NTRS)

Henderson, H. R.; Hilton, D. A.

1974-01-01

Sonic-boom pressure signatures recorded during the ascent phase of Apollo 17 are presented. The measurements were obtained onboard six U.S. Navy ships positioned along the ground track of the spacecraft vehicle in the area of expected focus resulting from the flight path and acceleration of the vehicle. Tracings of the measured signatures are presented along with values of the maximum positive overpressure, positive impulse, signature duration, and bowshock rise time. Also included are brief descriptions of the ships and their location, the deployment of the sonic-boom instrumentation, flight profiles and operating conditions for the launch vehicle and spacecraft, surface-weather and sea-state information at the measuring sites, and high-altitude weather information for the general measurement areas. Comparisons of the measured and predicted sonic-boom overpressures for the Apollo 17 mission are presented. The measured data are also compared with data from the Apollo 15 and 16 missions and data from flight test programs of various aircraft.

Investigation on the relationship between overpressure and sub-harmonic response from encapsulated microbubbles

NASA Astrophysics Data System (ADS)

Wu, Jun; Fan, Ting-Bo; Xu, Di; Zhang, Dong

2014-10-01

Sub-harmonic component generated from microbubbles is proven to be potentially used in noninvasive blood pressure measurement. Both theoretical and experimental studies are performed in the present work to investigate the dependence of the sub-harmonic generation on the overpressure with different excitation pressure amplitudes and pulse lengths. With 4-MHz ultrasound excitation at an applied acoustic pressure amplitude of 0.24 MPa, the measured sub-harmonic amplitude exhibits a decreasing change as overpressure increases; while non-monotonic change is observed for the applied acoustic pressures of 0.36 MPa and 0.48 MPa, and the peak position in the curve of the sub-harmonic response versus the overpressure shifts toward higher overpressure as the excitation pressure amplitude increases. Furthermore, the exciting pulse with long duration could lead to a better sensitivity of the sub-harmonic response to overpressure. The measured results are explained by the numerical simulations based on the Marmottant model. The numerical simulations qualitatively accord with the measured results. This work might provide a preliminary proof for the optimization of the noninvasive blood pressure measurement through using sub-harmonic generation from microbubbles.

Detecting overpressure using the Eaton and Equivalent Depth methods in Offshore Nova Scotia, Canada

NASA Astrophysics Data System (ADS)

Ernanda; Primasty, A. Q. T.; Akbar, K. A.

2018-03-01

Overpressure is an abnormal high subsurface pressure of any fluids which exceeds the hydrostatic pressure of column of water or formation brine. In Offshore Nova Scotia Canada, the values and depth of overpressure zone are determined using the eaton and equivalent depth method, based on well data and the normal compaction trend analysis. Since equivalent depth method is using effective vertical stress principle and Eaton method considers physical property ratio (velocity). In this research, pressure evaluation only applicable on Penobscot L-30 well. An abnormal pressure is detected at depth 11804 feet as possibly overpressure zone, based on pressure gradient curve and calculation between the Eaton method (7241.3 psi) and Equivalent Depth method (6619.4 psi). Shales within Abenaki formation especially Baccaro Member is estimated as possible overpressure zone due to hydrocarbon generation mechanism.

Investigation of Thermophysical Parameters Properties for Enhancing Overpressure Mechanism Estimation. Case Study: Miri Area, West Baram Delta

NASA Astrophysics Data System (ADS)

Adha, Kurniawan; Yusoff, Wan Ismail Wan; Almanna Lubis, Luluan

2017-10-01

Determining the pore pressure data and overpressure zone is a compulsory part of oil and gas exploration in which the data can enhance the safety with profit and preventing the drilling hazards. Investigation of thermophysical parameters such as temperature and thermal conductivity can enhance the pore pressure estimation for overpressure mechanism determination. Since those parameters are dependent on rock properties, it may reflect the changes on the column of thermophysical parameters when there is abnormally in pore pressure. The study was conducted in “MRI 1” well offshore Sarawak, where a new approach method designed to determine the overpressure generation. The study was insisted the contribution of thermophysical parameters for supporting the velocity analysis method, petrophysical analysis were done in these studies. Four thermal facies were identified along the well. The overpressure developed below the thermal facies 4, where the pressure reached 38 Mpa and temperature was increasing significantly. The velocity and the thermal conductivity cross plots shows a linear relationship since the both parameters mainly are the function of the rock compaction. When the rock more compact, the particles were brought closer into contact and making the sound wave going faster while the thermal conductivity were increasing. In addition, the increment of temperature and high heat flow indicated the presence of fluid expansion mechanism. Since the shale sonic velocity and density analysis were the common methods in overpressure mechanism and pore pressure estimation. As the addition parameters for determining overpressure zone, the presence of thermophysical analysis was enhancing the current method, where the current method was the single function of velocity analysis. The presence of thermophysical analysis will improve the understanding in overpressure mechanism determination as the new input parameters. Thus, integrated of thermophysical technique and velocity analysis are important parameters in investigating the overpressure mechanisms and pore pressure estimation during oil and gas exploitation in the future.

Apparatus for reducing shock and overpressure

DOEpatents

Walter, C.E.

1975-01-28

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

Characteristic overpressure-impulse-distance curves for vapour cloud explosions using the TNO Multi-Energy model.

PubMed

Díaz Alonso, Fernando; González Ferradás, Enrique; Sánchez Pérez, Juan Francisco; Miñana Aznar, Agustín; Ruiz Gimeno, José; Martínez Alonso, Jesús

2006-09-21

A number of models have been proposed to calculate overpressure and impulse from accidental industrial explosions. When the blast is produced by ignition of a vapour cloud, the TNO Multi-Energy model is widely used. From the curves given by this model, data are fitted to obtain equations showing the relationship between overpressure, impulse and distance. These equations, referred herein as characteristic curves, can be fitted by means of power equations, which depend on explosion energy and charge strength. Characteristic curves allow the determination of overpressure and impulse at each distance.

Apparatus for reducing shock and overpressure

DOEpatents

Walter, C.E.

1975-10-21

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

CFD Assessment of Forward Booster Separation Motor Ignition Overpressure on ET XT 718 Ice/Frost Ramp

NASA Technical Reports Server (NTRS)

Tejnil, Edward; Rogers, Stuart E.

2012-01-01

Computational fluid dynamics assessment of the forward booster separation motor ignition over-pressure was performed on the space shuttle external tank X(sub T) 718 ice/frost ramp using the flow solver OVERFLOW. The main objective of this study was the investigation of the over-pressure during solid rocket booster separation and its affect on the local pressure and air-load environments. Delta pressure and plume impingement were investigated as a possible contributing factor to the cause of the debris loss on shuttle missions STS-125 and STS-127. A simplified computational model of the Space Shuttle Launch Vehicle was developed consisting of just the external tank and the solid rocket boosters with separation motor nozzles and plumes. The simplified model was validated by comparison to full fidelity computational model of the Space Shuttle without the separation motors. Quasi steady-state plume solutions were used to calibrate the thrust of the separation motors. Time-accurate simulations of the firing of the booster-separation motors were performed. Parametric studies of the time-step size and the number of sub-iterations were used to find the best converged solution. The computed solutions were compared to previous OVERFLOW steady-state runs of the separation motors with reaction control system jets and to ground test data. The results indicated that delta pressure from the overpressure was small and within design limits, and thus was unlikely to have contributed to the foam losses.

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2014-10-01 2014-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2013-10-01 2013-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

Environmental Impact Statement for the Space Shuttle Program

NASA Technical Reports Server (NTRS)

Malkin, M. S.

1978-01-01

Test firings and launches will release air pollutants causing a temporary localized small degradation in air quality near the tests or launch site. Areas adjacent to the site will also be subjected to moderate sound levels of predominantly low frequencies for short durations. During the launch phase, hydrogen chloride will be introduced into the stratosphere causing a small decrease in ozone. Temporary perturbations to the ionosphere will occur during orbital maneuvers and entry will have no significant effect on communication or radio wave propagation. As the Orbiter descends, a low magnitude sonic beam will be produced along the groundtrack with maximum overpressures occurring near the landing site. The overpressures will be infrequent, will vary in location and are of sufficiently low energy to be considered a momentary annoyance, if noticed at all. Major alternatives considered are discontinuation or postponement of the program, use of alternate propellants and neutralization of the ground cloud.

Shock wave interaction with L-shaped structures

NASA Astrophysics Data System (ADS)

Miller, Richard C.

1993-12-01

This study investigated the interaction of shock waves with L-shaped structures using the CTH hydrodynamics code developed by Sandia National Laboratories. Computer models of shock waves traveling through air were developed using techniques similar to shock tube experiments. Models of L-shaped buildings were used to determine overpressures achieved by the reflecting shock versus angle of incidence of the shock front. An L-shaped building model rotated 45 degrees to the planar shock front produced the highest reflected overpressure of 9.73 atmospheres in the corner joining the two wings, a value 9.5 times the incident overpressure of 1.02 atmospheres. The same L-shaped building was modeled with the two wings separated by 4.24 meters to simulate an open courtyard. This open area provided a relief path for the incident shock wave, creating a peak overpressure of only 4.86 atmospheres on the building's wall surfaces from the same 1.02 atmosphere overpressure incident shock wave.

Simulation and Measurements of Small Arms Blast Wave Overpressure in the Process of Designing a Silencer

NASA Astrophysics Data System (ADS)

Hristov, Nebojša; Kari, Aleksandar; Jerković, Damir; Savić, Slobodan; Sirovatka, Radoslav

2015-02-01

Simulation and measurements of muzzle blast overpressure and its physical manifestations are studied in this paper. The use of a silencer can have a great influence on the overpressure intensity. A silencer is regarded as an acoustic transducer and a waveguide. Wave equations for an acoustic dotted source of directed effect are used for physical interpretation of overpressure as an acoustic phenomenon. Decomposition approach has proven to be suitable to describe the formation of the output wave of the wave transducer. Electroacoustic analogies are used for simulations. A measurement chain was used to compare the simulation results with the experimental ones.

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... months, but at least twice each calendar year, inspect and test each pressure limiting device, relief... reliability of operation for the service in which it is used. (b) In the case of relief valves on pressure breakout tanks containing highly volatile liquids, each operator shall test each valve at intervals not...

Report on Transport and Loading of Explosives in the Femtosecond Tank, Room 1711A HEAF 00-010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, D L

2002-04-25

The current OSP associated with Room 1711A located in Building 191 (HEAF) sets a limit of 5 grams Net Explosive Weight (NEW) of explosives for the room. A question was raised as to the capability of that room to withstand the overpressure created by a detonation of 5 grams NEW of explosives. Calculations were inconclusive, but indicated the wallboard would not remain intact if there was a detonation of 5 grams NEW at a distance of eight feet from the wall. These calculations did not seem logical. To verify the hypothesis, a series of experiments were conducted in the 1more » Kilogram tank. The experiments consisted of exposing a pre-built double-sided wall with the same stud spacing and drywall thickness found in the walls of Room 1711A to various amounts of explosives to create expected overpressures. The objective of this test was to prove or disprove that the walls in room 1711A could withstand a detonation of 5 grams of high explosives and to determine if larger quantities of explosives could be worked on in the room while still providing the required level of protection for personnel outside the room. Testing has verified that not only can the walls withstand a 5 gram explosion, but a 10.75 gram explosion as well. A second test was conducted using 20 grams of explosive plus a detonator. Although the inner piece of drywall cracked, the outer piece of drywall maintained its integrity, thereby confining the effects of the anticipated overpressure to the room.« less

Brain Vulnerability to Repeated Blast Overpressure and Polytrauma

DTIC Science & Technology

2015-10-01

characterization of the mouse model of repeated blast also found no cumula- tive effect of repeated blast on cortical levels of reactive oxygen species [39]. C...overpressure in rats to investigate the cumulative effects of multiple blast exposures on neurologic status, neurobehavioral function, and brain...preclinical model of blast overpressure in rats to investigate the cumulative effects of multiple blast exposures using neurological, neurochemical

The Shock and Vibration Bulletin. Part 3. Acoustic and Vibration Testing, Impact and Blast

DTIC Science & Technology

1976-08-01

Research Institute, San Antonio, Texas DESIGN OF A BLAST LOAD GENERATOR FOR OVERPRESSURE TESTING .................................. 261I P. Lieberman...Mathews and B. W. Duggin, Sandia Laboratories, Albuquerque, New Mexico ESTIMATION OF SHIP SHOCK PARAMETERS FOR CONSISTENT DESIGN AND TEST SPECIFICATION G. C...Seattle, Washington COMPONENT TESTING OF LIQUID SHOCK ISOLATORS AND ELASTOMERS IN SUPPORT OF RECENT SHOCK ISOLATION SYSTEM DESIGNS AJ.IP. Ashley, Boeing

MORTALITY IN SMALL ANIMALS EXPOSED IN A SHOCK TUBE TO "SHARP"-RISING OVERPRESSURES OF 3-4 MSEC DURATION. Technical Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richmond, D.R.; Goldizen, V.C.; Clare, V.R.

1961-06-15

A total of 661 animals was exposed to sharp''-rising overpressures of 3 to 4 msec duration using a shock tube of novel design which produced a pressure pulse similar to that obtained with high explosives. The reflected shock overpressures associated with 50% lethality were 29.0, rabbit, respectively. Other observations included the time of death in mortally wounded animals and gross pathological lesions likely to contribute to mortality. Selected data from the literature bearing upon the influence of overpressure and pulse duration on lethality were reviewed. These included pulse durations ranging from less than 1 msec to 8 sec. The criticalmore » pulse duration, that duration shorter than which the overpressures required for mortality increases sharply, was noted to depend upon animal size and to be of the order of many hundreds of microseconds to very few milliseconds for smaller'' animals and a few to many tens of milliseconds for larger'' animals. (auth)« less

The interdisciplinary use of ;overpressure;

NASA Astrophysics Data System (ADS)

Peacock, D. C. P.; Anderson, M. W.; Rotevatn, A.; Sanderson, D. J.; Tavarnelli, E.

2017-07-01

Overpressure is a polysemic word that has a variety of meanings within and across different disciplines. This is likely to be a particular problem in analysis of geothermal resources, where reservoir engineers, volcanologists and structural geologists may each confidently use overpressure but mean different things. We suggest that, to avoid confusion, the term should be carefully and accurately defined whenever used, and ideally only used to mean fluid pressure in excess of hydrostatic pressure.

Redeposition of a straight-sided buckle under pressure.

PubMed

Colin, Jérôme; Coupeau, Christophe; Durinck, Julien; Cimetière, Alain; Grilhé, Jean

2014-03-01

The unilateral buckling of a stressed thin film on a substrate has been investigated theoretically in the framework of the Föppl-von Kármán theory of thin plates when an increasing overpressure is considered onto the upper free surface of the film. It is found that, depending on the initial stress in the film and overpressure, two scenarios of evolution may occur. The snap-through of the one-dimensional buckle leading to the full redeposition should take place for low values of the initial stress. When the initial stress exceeds a critical value, a partial redeposition of the buckle should proceed as the overpressure increases. A snap-through while the redeposition mechanism has taken place should also occur for higher values of the overpressure.

Influence of headspace pressure on methane production in Biochemical Methane Potential (BMP) tests.

PubMed

Valero, David; Montes, Jesús A; Rico, José Luis; Rico, Carlos

2016-02-01

The biochemical methane potential test is the most commonly applied method to determine methane production from organic wastes. One of the parameters measured is the volume of biogas produced which can be determined manometrically by keeping the volume constant and measuring increases in pressure. In the present study, the effect of pressure accumulation in the headspace of the reactors has been studied. Triplicate batch trials employing cocoa shell, waste coffee grounds and dairy manure as substrates have been performed under two headspace pressure conditions. The results obtained in the study showed that headspace overpressures higher than 600mbar affected methane production for waste coffee grounds. On the contrary, headspace overpressures within a range of 600-1000mbar did not affect methane production for cocoa shell and dairy manure. With the analyses performed in the present work it has not been possible to determine the reasons for the lower methane yield value obtained for the waste coffee grounds under high headspace pressures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study on the Rationality and Validity of Probit Models of Domino Effect to Chemical Process Equipment caused by Overpressure

NASA Astrophysics Data System (ADS)

Sun, Dongliang; Huang, Guangtuan; Jiang, Juncheng; Zhang, Mingguang; Wang, Zhirong

2013-04-01

Overpressure is one important cause of domino effect in accidents of chemical process equipments. Some models considering propagation probability and threshold values of the domino effect caused by overpressure have been proposed in previous study. In order to prove the rationality and validity of the models reported in the reference, two boundary values of three damage degrees reported were considered as random variables respectively in the interval [0, 100%]. Based on the overpressure data for damage to the equipment and the damage state, and the calculation method reported in the references, the mean square errors of the four categories of damage probability models of overpressure were calculated with random boundary values, and then a relationship of mean square error vs. the two boundary value was obtained, the minimum of mean square error was obtained, compared with the result of the present work, mean square error decreases by about 3%. Therefore, the error was in the acceptable range of engineering applications, the models reported can be considered reasonable and valid.

Nankai Stress History and Implications for an Overpressured Decollement

NASA Astrophysics Data System (ADS)

Moran, K.; O'Regan, M.

2005-12-01

The Nankai Trough, formed from the subduction of the Shikoku Basin beneath the island arc of southwestern Japan, is a relatively young accretionary complex converging at a rate of ~4 cm/yr [Shipboard Scientific Party, 2001a]. The region was studied during the Deep Sea Drilling Project and on three Ocean Drilling Program (ODP) Legs-131, 190 and 196. Three sites visited during these Legs form a single cross-margin transect (dubbed the Muroto Transect) that traverses the leading edge of the Nankai accretionary prism, from seaward of the deformation front at Site 1173, to close to the deformation front (Site 1174), and landward to the first frontal thrust (Site 808). The decollement, which forms the major boundary between the converging plates, occurs within the Lower Shikoku Basin stratigraphic unit. The ODP sites were drilled and cored to depths below the decollement (Sites 808 and 1174) and the proto-decollement (Site 1173). Here we present consolidation test results [Moran et al., 1993] that are consistent with porosity-depth functions from core and log measurements for the Lower Shikoku Basin sediments, assuming that the decollement is an overpressured seal. At 1173, where a true decollement has not yet formed, moderate fluid overpressures occur that can be fully attributed to high turbiditic sedimentation rates. Forward modeling of this site into the deformation front over a period of ~300 ky shows that the present 1173 porosity-depth function matches the porosity-depth function at 1174. These results suggest that the young decollement on the Muroto Transect at the deformation front and landward is highly overpressured and forms a seal to sediments below that can be classically modeled as a one-dimensional consolidation system.

Ultrafast eclogite formation via melting-induced overpressure

NASA Astrophysics Data System (ADS)

Chu, Xu; Ague, Jay J.; Podladchikov, Yury Y.; Tian, Meng

2017-12-01

The conventional wisdom holds that metamorphic reactions take place at pressures near-lithostatic so that the thermodynamic pressure, reflected by the mineral assemblage, is directly correlated with depth. On the other hand, recent field-based observations and geodynamic simulations suggest that heterogeneous stress and significant pressure deviations above lithostatic (overpressure) can occur in Earth's crust. Here we show that eclogite, normally interpreted to form at great depths in subduction zones and Earth's mantle, may form at much shallower depths via local overpressure generated in crustal shear zones. The eclogites studied crop out as lenses hosted by felsic paragneiss in a sheared thrust slice and represent a local pressure and temperature anomaly in the Taconic orogenic belt, southern New England. Sharply-defined chemical zones in garnet, which record ∼5 kbar pressure rise and fall accompanied by a temperature increase of 150-200 °C, demonstrate extremely short timescales of diffusion. This requires anomalously fast compression (∼500 yrs) and decompression. We use coupled phase equilibria and garnet diffusion forward modeling to fit the observed garnet profiles and test the likely P- T- t paths using a Monte Carlo-type approach, accounting for off-center sectioning of garnet. The simulation shows that a ∼5 kbar pressure increase after the temperature peak is necessary to reproduce the garnet zoning. Remarkably, this post-peak-T compression (from 9 kbar to 14 kbar) lasted only ∼500 yrs. If the compression was due to burial along a lithostatic pressure gradient, the descent speed would exceed 30 m yr-1, defying any observed or modeled subduction rates. Local overpressure in response to partial melting in a confined volume (Vrijmoed et al., 2009) caused by transient shear heating can explain the ultra-fast compression without necessitating burial to great depth.

Overpressure Prediction From Seismic Data: Implications on Drilling Safety

NASA Astrophysics Data System (ADS)

Osinowo, O. O.; Oladunjoye, M. A.; Olayinka, A. I.

2007-12-01

High rate of sediment influx into the Niger Delta via river Niger coupled with high rate of basin subsidence, very thick clayey members of Agbada and Akata Formations as well as prevailing presence of growth faults had been identified as the main factors responsible for overpressure generation and preservation in the Niger Delta basin. Analysis of porosity dependent parameters such as interval transit times and interval velocities derived from the seismic records of a field in the Western Niger Delta revealed the presence of overpressured formation at depth of 8670 feet, which is the top of the overpressured zone. The plot of interval transit times against depth gave a positive deflection from normal at the region of overpressure while interval velocity plot gave negative deflection; the ratio of this deviation in both cases is as high as 1.52. Pressure gradient in the upper, normally pressured part of the field was determined to be 0.465 psi/ft., which is within the established normal pressure gradient range in Niger Delta, while the abnormal formation pressure gradient in the overpressured region was determined to be 0.96 psi/ft., and this is also within the published abnormal pressure gradient range of 0.71 to 1.1 psi/ft. in Niger Delta. Formation fracture pressure gradients were determined from the formation pressure information to be 0.66psi/ft. in the upper part of the field and 1.2psi/ft. in the overpressured horizon. Mud weight window (MWW); mud density range necessary to prevent formation kick without initiating hydraulic fracturing was determined to be 10.2 to 12.5lbm/gal in the upper part of the field and 22.1 to 22.63lbm/gal in the overpressured horizon. MWW is indispensable for the selection of the mud pump type, capacity, pumping rate and mud densities at different formation pressure regimes. Overpressure prediction is also requisite for drilling program design, casing design as well as rig capacity choice before spudding. It is necessary to reduce well construction risk, save drilling hour as well as cut down drilling cost. If adequate predictions are not taken however, drilling hazards known as blowout may occur. Blowout, an uncontrollable flow of formation fluid into the well has made oil exploration and exploitation activities in Niger Delta, Southern Nigeria, a curse for the people rather than a blessing because considerable numbers of wells blew out during well construction activities, hence the characteristic oil spill which had degraded the environment, making fishing operation, a source of livelihood of the people difficult. Therefore the need for overpressure prediction as a guide for safe drilling, especially in unfamiliar exploration environments.

Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults

PubMed Central

Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

2015-01-01

Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3MJ and a 6.3MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers. PMID:26230392

Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults.

PubMed

Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

2015-01-01

Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3 MJ and a 6.3 MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers.

Repeated Low-Level Blast Exposure: A Descriptive Human Subjects Study.

PubMed

Carr, Walter; Stone, James R; Walilko, Tim; Young, Lee Ann; Snook, Tianlu Li; Paggi, Michelle E; Tsao, Jack W; Jankosky, Christopher J; Parish, Robert V; Ahlers, Stephen T

2016-05-01

The relationship between repeated exposure to blast overpressure and neurological function was examined in the context of breacher training at the U.S. Marine Corps Weapons Training Battalion Dynamic Entry School. During this training, Students are taught to apply explosive charges to achieve rapid ingress into secured buildings. For this study, both Students and Instructors participated in neurobehavioral testing, blood toxin screening, vestibular/auditory testing, and neuroimaging. Volunteers wore instrumentation during training to allow correlation of human response measurements and blast overpressure exposure. The key findings of this study were from high-memory demand tasks and were limited to the Instructors. Specific tests showing blast-related mean differences were California Verbal Learning Test II, Automated Neuropsychological Assessment Metrics subtests (Match-to-Sample, Code Substitution Delayed), and Delayed Matching-to-Sample 10-second delay condition. Importantly, apparent deficits were paralleled with functional magnetic resonance imaging using the n-back task. The findings of this study are suggestive, but not conclusive, owing to small sample size and effect. The observed changes yield descriptive evidence for potential neurological alterations in the subset of individuals with occupational history of repetitive blast exposure. This is the first study to integrate subject instrumentation for measurement of individual blast pressure exposure, neurocognitive testing, and neuroimaging. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

14 CFR 417.229 - Far-field overpressure blast effects analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... characteristics; (2) The potential for broken windows due to peak incident overpressures below 1.0 psi and related... the potentially affected windows, including their size, location, orientation, glazing material, and...

Rapid sedimentation and overpressure in shallow sediments of the Bering Trough, offshore southern Alaska

NASA Astrophysics Data System (ADS)

Daigle, Hugh; Worthington, Lindsay L.; Gulick, Sean P. S.; Van Avendonk, Harm J. A.

2017-04-01

Pore pressures in sediments at convergent margins play an important role in driving chemical fluxes and controlling deformation styles and localization. In the Bering Trough offshore Southern Alaska, extreme sedimentation rates over the last 140 kyr as a result of glacial advance/retreats on the continental shelf have resulted in elevated pore fluid pressures in slope sediments overlying the Pamplona Zone fold and thrust belt, the accretionary wedge resulting from subduction of the Yakutat microplate beneath the North American Plate. Based on laboratory experiments and downhole logs acquired at Integrated Ocean Drilling Program Site U1421, we predict that the overpressure in the slope sediments may be as high as 92% of the lithostatic stress. Results of one-dimensional numerical modeling accounting for changes in sedimentation rate over the last 130 kyr predicted overpressures that are consistent with our estimates, suggesting that the overpressure is a direct result of the rapid sedimentation experienced on the Bering shelf and slope. Comparisons with other convergent margins indicate that such rapid sedimentation and high overpressure are anomalous in sediments overlying accretionary wedges. We hypothesize that the shallow overpressure on the Bering shelf/slope has fundamentally altered the deformation style within the Pamplona Zone by suppressing development of faults and may inhibit seismicity by focusing faulting elsewhere or causing deformation on existing faults to be aseismic. These consequences are probably long-lived as it may take several million years for the excess pressure to dissipate.

When Geology is the Primary Impediment to Making Money (or not losing it), you can get a lot of Spectacular Data Very Quickly that you then have to Interpret: Overpressure and Slope Failure in the Oil Industry

NASA Astrophysics Data System (ADS)

Orange, D. L.; McConnell, D.; Jeanjean, P.; Thomson, J.; Saffer, D.; Demetriou, D.; Decker, J.; Teas, P. A.; Angell, M.

2005-12-01

IODP Leg 308 is one of those cases where academia is following industry. Since the early to mid 1990's, the oil industry has recognized that confined zones of overpressure, particularly in the case of unconsolidated sand units, can lead to the total loss of an offshore well (whose cost may easily exceed 10M). The recognition of this phenomenon, termed "Shallow Water Flow" in the oil patch, lead to a renewed effort to identify hazardous horizons ahead of drilling, and to quantify their hazard potential ("geohazard") through detailed field studies and in situ measurements.Shallow water flow affects individual wells and well templates, but overpressure-driven slope failure can impact an entire deepwater facility (whose cost can approach or exceed billions of dollars). In this presentation, we will introduce a number of seafloor developments (including both Gulf of Mexico and international projects) where geophysical data suggested the presence of overpressure and the possibility of overpressure-driven slope failure. We will show high resolution seafloor and sub-surface geophysical data of distinctive failures that suggest internal forcing, and show in situ pore pressure measurements (to 500m below sea floor) that quantify the magnitude and distribution of overpressure. In all of the cases we will show, wells and/or seafloor facilities were moved to take advantage of less hazardous locations.

Overpressure and consolidation near the seafloor of Brazos-Trinity Basin IV, northwest deepwater Gulf of Mexico

NASA Astrophysics Data System (ADS)

Schneider, Julia; Flemings, Peter B.; Dugan, Brandon; Long, Hui; Germaine, John T.

2009-05-01

Pore water overpressures (u*) within mudstones beneath Brazos-Trinity Basin IV (deepwater Gulf of Mexico, offshore Texas) are greater than 70% of the hydrostatic vertical effective stress (σ'vh) [λ* = 0.7 = (u*/σ'vh)]. These results are compatible with recent observations that suggest sedimentation rates in this region are rapid (6 mm/a). We compare the petrophysical properties and pore pressures within a 127-m-thick package of mudstone penetrated at two locations: Integrated Ocean Drilling Program (IODP) sites U1319 and U1320. Site U1319 is at the margin of Brazos-Trinity Basin IV, whereas Site U1320 lies at its center, beneath 180 m of turbidite fill. Experimentally derived preconsolidation stresses and an in situ pore pressure measurement record overpressure at Site U1319 and Site U1320 (λ* ˜ 0.2 to 0.8 and λ* ˜ 0.8, respectively). We use these data to define an average vertical effective stress gradient. Assuming that void ratio (e) is proportional to the log of vertical effective stress (σ'v), we predict pore pressures (u) throughout the mudstone at both sites using bulk density data. Overpressures are greater at Site U1320 due to rapid deposition of the overlying turbidites. However, a large fraction of the overpressure induced by the turbidite load applied at Site U1320 has dissipated by drainage into the overlying basin fill. High overpressures near the seafloor drive shallow fluid flow, reduce slope stability, and may explain large submarine landslides.

A parametric study of perforated muzzle brakes

NASA Astrophysics Data System (ADS)

Dillon, Robert E., Jr.; Nagamatsu, H. T.

1993-07-01

A firing test was conducted to study the parameters influencing the recoil efficiency and the blast characteristics of perforated muzzle brakes. Several scaled (20 mm) devices were tested as candidates for the 105 mm Armored Gun System (AGS). Recoil impulse, blast overpressures, muzzle velocity, sequential spark shadowgraphs, and photographs of the muzzle flash were obtained. A total of nine different perforated brakes were tested as well as a scaled M 198 double muzzle brake.

MISTY PICTURE EVENT, Test Execution Report

DTIC Science & Technology

1987-11-30

testbed at overpressures ranging from 10 psi (83 kPa) to 3.4 psi (23 kPa). A series of experiments were positioned near the Thermal Radiation Sources...to include scheduling, construction, photography, and recording systems. (2) Formulate and direct the safety and security plans for the test series and...ANFO stacked charges multiburst test at Planet Ranch, AZ in 1978, e. MILL RACE (MISTY CASTLE Series I) - 600 ton ANFO surface stacked charge at WSMR in

The Range Safety Debris Catalog Analysis in Preparation for the Pad Abort One Flight Test

NASA Technical Reports Server (NTRS)

Kutty, Prasad; Pratt, William

2010-01-01

With each flight test a Range Safety Data Package is assembled to understand the potential consequences of various failure scenarios. Debris catalog analysis considers an overpressure failure of the Abort Motor and the resulting debris field created 1. Characterize debris fragments generated by failure: weight, shape, and area 2. Compute fragment ballistic coefficients 3. Compute fragment ejection velocities.

An Evaluation of the Compressive Properties of Helmet Pads Pre- and Post-Shock Wave Overpressure Exposure

DTIC Science & Technology

2015-08-14

by ANSI Std. Z39.18 BLAST DROP TESTS BRAIN DAMAGE VISCOELASTICITY BRAIN CONCUSSION ...Cambridge, UK: Cambridge University Press, 1997. [5] W. C. Moss and M. J. King, "Impact response of US Army and National Football League helmet pad

BLAST LOADING AND RESPONSE OF UNDERGROUND CONCRETE-ARCH PROTECTIVE STRUCTURES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flathau, W.J.; Breckenridge, R.A.; Wiehle, C.K.

1959-06-01

Four reinforced-concrete arch structures, with the top of arch crown 4 ft below ground surface, were exposed at high overpressure ranges from Priscilla Burst in order to obtain data on their resistance to blast, radiation, and missile hazards. The four structures received actual air overpressures of 56, 124, and 199 psi and suffered only minor damage, all remaining structurally serviceable. The entranceway used for the structures sealed out the air pressure. It was not designed to attenuate radiation and thus did not provide adequate radiation protection for personnel. There were no missile and apparently no dust hazards in any ofmore » the structures. Results of the test indicate that an underground reinforced-concrete arch is an excellent structural shape for resisting the effects of a kiloton-range air burst. (C.H.)« less

Reduction of 5in./54 Gun Blast Overpressure by Means of an Aqueous Foam- Filled Muzzle Device

DTIC Science & Technology

1981-08-01

aqueous foams have a certain drainage rate that causes the expansion ratio and bubble size to increase progressively. The Rockwood Aquafoam AFFF yields the...NSWC TR 81-128 REDUCTION OF 5"/54 GUN BLAST OVERPRESSURE BY MEANS OF AN AQUEOUS FOAM -FILLED MUZZLE DEVICE by G. STEVENS MILLER RICHARD E. MILLER, JR...128 4. TITLE (ad Subtitle) S. TYPE O r REPORT & PERIOD COVERED REDUCTION OF 5!V54 GUN BLAST OVERPRESSURE Final BY MEANS OF AN AQUEOUS FOAM -FILLED a

Final Programmatic Environmental Impact Statement for Defense Threat Reduction Agency (DTRA) Activities on White Sands Missile Range, New Mexico

DTIC Science & Technology

2007-05-01

taggants south of Mockingbird Gap and the limited number of simulants met the Agency requirements. It was recognized at that time if either situation...from attack. * A new test bed for HTD testing is proposed at Mockingbird South. Alternative one, the preferred alternative, would allow DTRA to expand...HTD tests, and explosive tests have the potential to directly injure or kill native fauna from flying debris and blast overpressure. Craters

Method of pressurizing and stabilizing rock by periodic and repeated injections of a settable fluid of finite gel strength

DOEpatents

Colgate, Stirling A.

1983-01-01

A finite region of overpressure can be created in solid underground formations by the periodic injection of a fluid that has finite gel strength that subsequently, after each injection, partially sets--i.e., equivalently becomes a very much stronger gel. A region of overpressure is a region in which the static, locked in pressure is larger than what was there before. A region of overpressure can be used to prevent a roof of a tunnel from caving by adding compressive stresses in the roof. A sequence of regions of overpressure can be used to lift an arch or dome underground, squeeze off water or gas flows, stabilize dams, foundations, large underground rooms, etc. In general, the stress or pressure distribution in rock can be altered and engineered in a fashion that is more advantageous than what would have been the case without overstressing.

Method of pressurizing and stabilizing rock by periodic and repeated injections of a settable fluid of finite gel strength

DOEpatents

Colgate, S.A.

1983-01-25

A finite region of overpressure can be created in solid underground formations by the periodic injection of a fluid that has finite gel strength that subsequently, after each injection, partially sets--i.e., equivalently becomes a very much stronger gel. A region of overpressure is a region in which the static, locked in pressure is larger than what was there before. A region of overpressure can be used to prevent a roof of a tunnel from caving by adding compressive stresses in the roof. A sequence of regions of overpressure can be used to lift an arch or dome underground, squeeze off water or gas flows, stabilize dams, foundations, large underground rooms, etc. In general, the stress or pressure distribution in rock can be altered and engineered in a fashion that is more advantageous than what would have been the case without overstressing. 3 figs.

Gas pipeline relief valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bright, G.F.

1974-01-01

A discussion of the increasing activity of natural gas pipeline companies in the analysis of the overpressure protection methods for complying with the provisions of Part 192, Title 49, Code of Federal Regulations ''Transportation of Natural and Other Gas by Pipelines; Minimum Federal Safety Standards'' and with the USAS B31.8 Code covers the basic requirements for protection against accidental overpressure as being essentially the same in both documents, i.e., at the maximum allowable operating overpressure in a gas system can be exceeded either at a compressor station or downstream of a pressure control valve; mandatory use of overpressure protection devicesmore » in these situations, except for those cases which exempt some service regulators because the distribution system pressure is less than 60 psig and six other requirements of design, performance, and size are met; and basic design requirements of a pressure relief or limiting station and the components used.« less

Elastic properties of overpressured and unconsolidated sediments

USGS Publications Warehouse

Lee, Myung W.

2003-01-01

Differential pressure affects elastic velocities and Poisson?s ratio of sediments in such a way that velocities increase as differential pressure increases. Overpressured zones in sediments can be detected by observing an increase in Poisson?s ratio with a corresponding drop in elastic velocities. In highly overpressured sands, such as shallow water flow sands, the P-to S-wave velocity ratio (Vp/Vs) is very high, on the order of 10 or higher, due to the unconsolidated and uncemented nature of sediments. In order to predict elastic characteristics of highly overpressured sands, Biot-Gassmann theory by Lee (BGTL) is used with a variable exponent n that depends on differential pressure and the degree of consolidation/compaction. The exponent n decreases as differential pressure and the degree of consolidation increases, and, as n decreases, velocity increases and Vp/Vs decreases. The predicted velocity ratio by BGTL agrees well with the measured velocity ratio at low differential pressure for unconsolidated sediments.

Use of hydraulic head to estimate volumetric gas content and ebullition flux in northern peatlands

USGS Publications Warehouse

Rosenberry, Donald O.; Glaser, Paul H.; Siegel, Donald I.; Weeks, Edwin P.

2003-01-01

Hydraulic head was overpressured at middepth in a 4.2‐m thick raised bog in the Glacial Lake Agassiz peatlands of northern Minnesota, and fluctuated in response to atmospheric pressure. Barometric efficiency (BE), determined by calculating ratios of change in hydraulic head to change in atmospheric pressure, ranged from 0.05 to 0.15 during July through November of both 1997 and 1998. The overpressuring and a BE response were caused by free‐phase gas contained primarily in the center of the peat column between two or more semielastic, semiconfining layers of more competent peat. Two methods were used to determine the volume of gas bubbles contained in the peat, one using the degree of overpressuring in the middepth of the peat, and the other relating BE to specific yield of the shallow peat. The volume of gas calculated from the overpressuring method averaged 9%, assuming that the gas was distributed over a 2‐m thick overpressured interval. The volume of gas using the BE method averaged 13%. Temporal changes in overpressuring and in BE indicate that the volume of gaseous‐phase gas also changed with time, most likely because of rapid degassing (ebullition) that allowed sudden loss of gas to the atmosphere. Estimates of gas released during the largest ebullition events ranged from 0.3 to 0.7 mol m−2 d−1. These ebullition events may contribute a significant source of methane and carbon dioxide to the atmosphere that has so far largely gone unmeasured by gas‐flux chambers or tower‐mounted sensors.

Prediction of Launch Vehicle Ignition Overpressure and Liftoff Acoustics

NASA Technical Reports Server (NTRS)

Casiano, Matthew

2009-01-01

The LAIOP (Launch Vehicle Ignition Overpressure and Liftoff Acoustic Environments) program predicts the external pressure environment generated during liftoff for a large variety of rocket types. These environments include ignition overpressure, produced by the rapid acceleration of exhaust gases during rocket-engine start transient, and launch acoustics, produced by turbulence in the rocket plume. The ignition overpressure predictions are time-based, and the launch acoustic predictions are frequency-based. Additionally, the software can predict ignition overpressure mitigation, using water-spray injection into the rocket exhaust stream, for a limited number of configurations. The framework developed for these predictions is extensive, though some options require additional relevant data and development time. Once these options are enabled, the already extensively capable code will be further enhanced. The rockets, or launch vehicles, can either be elliptically or cylindrically shaped, and up to eight strap-on structures (boosters or tanks) are allowed. Up to four engines are allowed for the core launch vehicle, which can be of two different types. Also, two different sizes of strap-on structures can be used, and two different types of booster engines are allowed. Both tabular and graphical presentations of the predicted environments at the selected locations can be reviewed by the user. The output includes summaries of rocket-engine operation, ignition overpressure time histories, and one-third octave sound pressure spectra of the predicted launch acoustics. Also, documentation is available to the user to help him or her understand the various aspects of the graphical user interface and the required input parameters.

46 CFR 118.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... piping must be capped within the space protected at the first joint between the nozzles and the storage... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from overpressurization. (3) Nozzles must be approved by the Commandant. (4) When...

46 CFR 118.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... piping must be capped within the space protected at the first joint between the nozzles and the storage... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from overpressurization. (3) Nozzles must be approved by the Commandant. (4) When...

46 CFR 118.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... piping must be capped within the space protected at the first joint between the nozzles and the storage... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from overpressurization. (3) Nozzles must be approved by the Commandant. (4) When...

46 CFR 181.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... protected at the first joint between the nozzles and the storage cylinders. (iii) A small independent system... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from over-pressurization. (3) Nozzles must be approved by the Commandant. (4) When...

46 CFR 181.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... protected at the first joint between the nozzles and the storage cylinders. (iii) A small independent system... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from over-pressurization. (3) Nozzles must be approved by the Commandant. (4) When...

46 CFR 181.410 - Fixed gas fire extinguishing systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... protected at the first joint between the nozzles and the storage cylinders. (iii) A small independent system... and the first nozzle in the system must be capped and pneumatically tested for a period of 10 minutes... protect the piping from over-pressurization. (3) Nozzles must be approved by the Commandant. (4) When...

The development of a cryogenic over-pressure pump

NASA Astrophysics Data System (ADS)

Alvarez, M.; Cease, H.; Flaugher, B.; Flores, R.; Garcia, J.; Lathrop, A.; Ruiz, F.

2014-01-01

A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL).

Effect of Surface Roughness on Characteristics of Spherical Shock Waves

NASA Technical Reports Server (NTRS)

Huber, Paul W.; McFarland, Donald R.

1959-01-01

Measurements of peak overpressure and Mach stem height were made at four burst heights. Data were obtained with instrumentation capable of directly observing the variation of shock wave movement with time. Good similarity of free air shock peak overpressure with larger scale data was found to exist. The net effect of surface roughness on shock peak overpressures slightly. Surface roughness delayed the Mach stem formation at the greatest charge height and lowered the growth at all burst heights. A similarity parameter was found which approximately correlates the triple point path at different burst heights.

Non-reclosing pressure relief device for vacuum systems

DOEpatents

Swansiger, William A.

1994-01-01

A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife.

Non-reclosing pressure relief device for vacuum systems

DOEpatents

Swansiger, W.A.

1994-02-08

A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife. 6 figures.

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

NASA Astrophysics Data System (ADS)

Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

2015-05-01

New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

Rocket Launch-Induced Vibration and Ignition Overpressure Response

NASA Technical Reports Server (NTRS)

Caimi, Raoul; Margasahayam, Ravi; Nayfeh, Jamal; Thompson, Karen (Technical Monitor)

2001-01-01

Rocket-induced vibration and ignition overpressure response environments are predicted in the low-frequency (5 to 200 hertz) range. The predictions are necessary to evaluate their impact on critical components, structures, and facilities in the immediate vicinity of the rocket launch pad.

Pretest Round Robin Analysis of 1:4-Scale Prestressed Concrete Containment Vessel Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

HESSHEIMER,MICHAEL F.; LUK,VINCENT K.; KLAMERUS,ERIC W.

The purpose of the program is to investigate the response of representative scale models of nuclear containment to pressure loading beyond the design basis accident and to compare analytical predictions to measured behavior. This objective is accomplished by conducting static, pneumatic overpressurization tests of scale models at ambient temperature. This research program consists of testing two scale models: a steel containment vessel (SCV) model (tested in 1996) and a prestressed concrete containment vessel (PCCV) model, which is the subject of this paper.

Submarine Hydraulic Fluid Explosion Mitigation and Fire Threats to Ordnance

DTIC Science & Technology

2005-01-18

capable of absorbing large amounts of energy from a developing explosion if the mist can be delivered, in sufficient quantity, to the point of origin of...doors (H8, H13 , H14, D10, D11, SI and S2 in Figure 1) during the explosion tests. In addition, the frame bay ducts that connect 3 the torpedo room and...appreciable impact on the overpressure, explosion tests were run with and without the dummy ordnance. Two replicate tests of each configuration were conducted

A Novel Anti-Pollution Filter for Volatile Agents During Cardiopulmonary Bypass: Preliminary Tests.

PubMed

Nigro Neto, Caetano; Landoni, Giovanni; Tardelli, Maria Angela

2017-08-01

Concerns regarding pollution of the operating room by volatile anesthetics and effects on atmospheric ozone depletion exist. Volatile agents commonly are used during cardiopulmonary bypass to provide anesthesia independent of any supposed myocardial protective effects. The authors' aim was to create and to assess the performance of a prototype filter for volatile agents to be connected to the cardiopulmonary bypass circuit to avoid the emission of volatile agents to the operating room, and also to the environment without causing damage to the membrane oxygenator. Observational trial. University hospital. Prototype filter for volatile agents. The prototype filter was tested in a single ex vivo experiment. The main data measured during the test were pressure drop to detect interference with the performance of the oxygenator, back pressure to detect overpressure to the outlet gas jacket of the oxygenator, analysis of exhaled sevoflurane after the membrane oxygenator, and after the filter to detect any presence of sevoflurane. The prototype filter adsorbed the sevoflurane eliminated through the outlet portion of the oxygenator. During the entire test, the back pressure remained constant (4 mmHg) and pressure drop varied from 243 mmHg to 247 mmHg. The prototype filter was considered suitable to absorb the sevoflurane, and it did not cause an overpressure to the membrane oxygenator during the test. Copyright © 2017 Elsevier Inc. All rights reserved.

Variability of measured sonic boom signatures. Volume 2: Data report

NASA Technical Reports Server (NTRS)

Elmer, K. R.; Joshi, M. C.

1994-01-01

Sonic boom signatures from two databases, the BOOMFILE and the XB-70, were analyzed in terms of C-weighted sound exposure level (CSEL), A-weighted sound exposure level (ASEL), and Stevens Mark VII perceived level (PLdB), as well as the more traditional peak positive overpressure and rise time. The variability of these parameters due to propagation through atmosphere was analyzed for different aircraft Mach number and altitude groups. The low Mach number/low altitude group had significantly greater variation in rise time, overpressure, and loudness level than the high Mach number/high altitude group. The loudness of measured booms were found to have a variation of up to 25 dB relative to the loudness of boom predicted for a non-turbulent atmosphere. This is due primarily to the steeper ray paths of the high Mach number/high altitude group and the corresponding shorter distances traveled by these rays through the lower atmosphere resulting in reduced refraction effects. The general trend of decreased overpressure and loudness level with increasing lateral distance was also seen. Sonic boom signatures from early morning flights had less variation in rise time and overpressure than afternoon flights because of reduced turbulence. Measures of asymmetry (difference between compression and expansion portion of the signature) showed that the variability in Delta loudness level was greater than the variability in Delta overpressure due to the large influence of turbulence on rise time. Lastly, analysis of data within 50 percent of lateral cutoff showed that the mean value for overpressure and loudness level was independent of time of day but that the frequency with which it occurred was greater in the morning. This is a clear indicator of increased turbulence in the afternoon.

Contributions to Crustal Mechanics on Europa from Subterranean Ocean Vibrations

NASA Astrophysics Data System (ADS)

Hayes, Robert

2016-03-01

The recent discovery of subduction zones on Europa demonstrated a significant step forward in understanding the moon's surface mechanics. This work promotes the additional consideration that the surface mechanics have contributions from small relative pressure differentials in the subsurface ocean that create cracks in the surface which are then filled, sealed and healed. Crack formation can be small, as interior pressure can relatively easily breach the surface crust, generating cracks followed by common fracture formation backfilled with frozen liquid. This process will slowly increase the overall surface area of the moon with each sealed crack and fracture increasing the total surface area. This creeping growth of surface area monotonically decreases subsurface pressure which can eventually catastrophically subduct large areas of surface and so is consistent with current knowledge of observational topology on Europa. This tendency is attributed to a relatively lower energy threshold to crack the surface from interior overpressures, but a higher energy threshold to crush the spherical surface due to subsurface underpressures. Proposed mechanisms for pressure differentials include tidal forces whose Fourier components build up the resonant oscillatory modes of the subsurface ocean creating periodic under and overpressure events below the crust. This mechanism provides a means to continually reform the surface of the moon over short geological time scales. This work supported in part by federal Grant NRC-HQ-84-14-G-0059.

Increased likelihood of induced seismicity in highly overpressured shale formations

NASA Astrophysics Data System (ADS)

Eaton, David W.; Schultz, Ryan

2018-05-01

Fluid-injection processes such as disposal of saltwater or hydraulic fracturing can induce earthquakes by increasing pore pressure and/or shear stress on faults. Natural processes, including transformation of organic material (kerogen) into hydrocarbon and cracking to produce gas, can similarly cause fluid overpressure. Here we document two examples from the Western Canada Sedimentary Basin where earthquakes induced by hydraulic fracturing are strongly clustered within areas characterized by pore-pressure gradient in excess of 15 kPa/m. Despite extensive hydraulic-fracturing activity associated with resource development, induced earthquakes are virtually absent in the Montney and Duvernay Formations elsewhere. Statistical analysis suggests a negligible probability that this spatial correlation developed by chance. This implies that, in addition to known factors such as anthropogenic pore-pressure increase and proximity to critically stressed faults, high in-situ overpressure of shale formations may also represent a controlling factor for inducing earthquakes by hydraulic fracturing. On a geological timescale, natural pore-pressure generation may lead to fault-slip episodes that regulate magnitude of formation-overpressure.

Statistical behavior of post-shock overpressure past grid turbulence

NASA Astrophysics Data System (ADS)

Sasoh, Akihiro; Harasaki, Tatsuya; Kitamura, Takuya; Takagi, Daisuke; Ito, Shigeyoshi; Matsuda, Atsushi; Nagata, Kouji; Sakai, Yasuhiko

2014-09-01

When a shock wave ejected from the exit of a 5.4-mm inner diameter, stainless steel tube propagated through grid turbulence across a distance of 215 mm, which is 5-15 times larger than its integral length scale , and was normally incident onto a flat surface; the peak value of post-shock overpressure, , at a shock Mach number of 1.0009 on the flat surface experienced a standard deviation of up to about 9 % of its ensemble average. This value was more than 40 times larger than the dynamic pressure fluctuation corresponding to the maximum value of the root-mean-square velocity fluctuation, . By varying and , the statistical behavior of was obtained after at least 500 runs were performed for each condition. The standard deviation of due to the turbulence was almost proportional to . Although the overpressure modulations at two points 200 mm apart were independent of each other, we observed a weak positive correlation between the peak overpressure difference and the relative arrival time difference.

Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

NASA Astrophysics Data System (ADS)

Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

2013-12-01

We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

Bubble migration in a compacting crystal-liquid mush

NASA Astrophysics Data System (ADS)

Boudreau, Alan

2016-04-01

Recent theoretical models have suggested that bubbles are unlikely to undergo significant migration in a compaction crystal mush by capillary invasion while the system remains partly molten. To test this, experiments of bubble migration during compaction in a crystal-liquid mush were modeled using deformable foam crystals in corn syrup in a volumetric burette, compacted with rods of varying weights. A bubble source was provided by sodium bicarbonate (Alka-Seltzer®). Large bubbles (>several crystal sizes) are pinched by the compacting matrix and become overpressured and deformed as the bubbles experience a load change from hydrostatic to lithostatic. Once they begin to move, they move much faster than the compaction-driven liquid. Bubbles that are about the same size as the crystals but larger than the narrower pore throats move by deformation or breaking into smaller bubbles as they are forced through pore restrictions. Bubbles that are less than the typical pore diameter generally move with the liquid: The liquid + bubble mixture behaves as a single phase with a lower density than the bubble-free liquid, and as a consequence it rises faster than bubble-free liquid and allows for faster compaction. The overpressure required to force a bubble through the matrix (max grain size = 5 mm) is modest, about 5 %, and it is estimated that for a grain size of 1 mm, the required overpressure would be about 25 %. Using apatite distribution in a Stillwater olivine gabbro as an analog for bubble nucleation and growth, it is suggested that relatively large bubbles initially nucleate and grow in liquid-rich channels that develop late in the compaction history. Overpressure from compaction allows bubbles to rise higher into hotter parts of the crystal pile, where they redissolve and increase the volatile content of the liquid over what it would have without the bubble migration, leading to progressively earlier vapor saturation during crystallization of the interstitial liquid. Bubbles can also move rapidly by `surfing' on porosity waves that can develop in a compacting mush.

A Wireless Lingual Feedback Device to Reduce Overpressures in Seated Posture: A Feasibility Study

PubMed Central

Chenu, Olivier; Vuillerme, Nicolas; Demongeot, Jacques; Payan, Yohan

2009-01-01

Background Pressure sores are localized injuries to the skin and underlying tissues and are mainly resulting from overpressure. Paraplegic peoples are particularly subjects to pressure sores because of long-time seated postures and sensory deprivation at the lower limbs. Methodology/Principal Findings Here we report outcomes of a feasibility trial involving a biofeedback system aimed at reducing buttock overpressure whilst an individual is seated. The system consists of (1) pressure sensors, (2) a laptop coupling sensors and actuator (3) a wireless Tongue Display Unit (TDU) consisting of a circuit embedded in a dental retainer with electrodes put in contact with the tongue. The principle consists in (1) detecting overpressures in people who are seated over long periods of time, (2) estimating a postural change that could reduce these overpressures and (3) communicating this change through directional information transmitted by the TDU.Twenty-four healthy subjects voluntarily participated in this study. Twelve healthy subjects initially formed the experimental group (EG) and were seated on a chair with the wireless TDU inside their mouth. They were asked to follow TDU orders that were randomly spread throughout the session. They were evaluated during two experimental sessions during which 20 electro-stimulations were sent. Twelve other subjects, added retrospectively, formed the control group (CG). These subjects participated in one session of the same experiment without any biofeedback.Three dependent variables were computed: (1) the ability of subjects to reach target posture (EG versus CG), (2) high pressure reductions after a biofeedback (EG versus CG) and (3) the level of these reductions relative to their initial values (EG only). Results show (1) that EG reached target postures in 90.2% of the trials, against 5,3% in the CG, (2) a significant reduction in overpressures in the EG compared to the CG and (3), for the EG, that the higher the initial pressures were, the more they were decreased. Conclusions/Significance The findings suggest that, in this trial, subjects were able to use a tongue tactile feedback system to reduce buttock overpressure while seated. Further evaluation of this system on paraplegic subjects remains to be done. PMID:19888336

46 CFR 153.365 - Liquid overpressurization protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pressure during liquid overfill at a specified cargo loading rate to that which the containment system is... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and...

46 CFR 153.365 - Liquid overpressurization protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... pressure during liquid overfill at a specified cargo loading rate to that which the containment system is... 46 Shipping 5 2012-10-01 2012-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and...

14 CFR 417.229 - Far-field overpressure blast effects analysis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4...

14 CFR 417.229 - Far-field overpressure blast effects analysis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4...

14 CFR 417.229 - Far-field overpressure blast effects analysis.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4...

14 CFR 417.229 - Far-field overpressure blast effects analysis.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4...

14 CFR Appendix B to Part 91 - Authorizations To Exceed Mach 1 (§ 91.817)

Code of Federal Regulations, 2010 CFR

2010-01-01

..., including an environmental analysis of that area meeting the requirements of paragraph (b) of this section... reach the surface outside of the designated test area. (d) An application is denied if the Administrator... number of 1 will not cause a measurable sonic boom overpressure to reach the surface. (b) For a flight...

14 CFR Appendix B to Part 91 - Authorizations To Exceed Mach 1 (§ 91.817)

Code of Federal Regulations, 2011 CFR

2011-01-01

..., including an environmental analysis of that area meeting the requirements of paragraph (b) of this section... reach the surface outside of the designated test area. (d) An application is denied if the Administrator... number of 1 will not cause a measurable sonic boom overpressure to reach the surface. (b) For a flight...

Fluid overpressures and strength of the sedimentary upper crust

NASA Astrophysics Data System (ADS)

Suppe, John

2014-12-01

The classic crustal strength-depth profile based on rock mechanics predicts a brittle strength σ1 -σ3 = κ(ρbar gz -Pf) that increases linearly with depth as a consequence of [1] the intrinsic brittle pressure dependence κ plus [2] an assumption of hydrostatic pore-fluid pressure, Pf = ρwgz. Many deep borehole stress data agree with a critical state of failure of this form. In contrast, fluid pressures greater than hydrostatic ρbar gz >Pf >ρw gz are normally observed in clastic continental margins and shale-rich mountain belts. Therefore we explore the predicted shapes of strength-depth profiles using data from overpressured regions, especially those dominated by the widespread disequilibrium-compaction mechanism, in which fluid pressures are hydrostatic above the fluid-retention depth zFRD and overpressured below, increasing parallel to the lithostatic gradient ρbar gz . Both brittle crustal strength and frictional fault strength below the zFRD must be constant with depth because effective stress (ρbar gz -Pf) is constant, in contrast with the classic linearly increasing profile. Borehole stress and fluid-pressure measurements in several overpressured deforming continental margins agree with this constant-strength prediction, with the same pressure-dependence κ as the overlying hydrostatic strata. The role of zFRD in critical-taper wedge mechanics and jointing is illustrated. The constant-strength approximation is more appropriate for overpressured crust than classic linearly increasing models.

Mechanisms of hydrocarbon migration in Mahakam delta, Kalimantan, Indonesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durand, B.; Bessereau, G.; Ungerer, P.H.

1986-05-01

In the Mahakam delta, hydrocarbons formed from landplant debris, either dispersed in clays or concentrated in coal levels. The hydrocarbon zone is located partly or entirely in overpressured zones. Hydrocarbon migration is primarily a polyphasic mechanism, i.e., water and hydrocarbons move in separate phases. When hydrocarbon generation occurs in normally pressured zones, hydrocarbons are easily expelled to close carrier beds. Then they migrate toward the top of structures through a network of abundant interconnected sand bodies. However, most hydrocarbons are generated in overpressured zones, in which they move preferentially toward the structural highs. Simultaneously, excess pressure is transmitted to themore » top of the structures because of the sedimentary load in the synclines, which results in a high pressure gradient at the top. This pressure gradient facilitates hydrocarbon filtration from overpressured zones to normally pressured zones, or it may cause hydraulic fracturing, which provides avenues for migration. Gas-rich hydrocarbons formed in deep overpressured zones, probably in a single phase owing to high temperature and pressures. The passage from overpressured zones to normally pressured zones resulted in decreased temperature and pressure, which produced several hydrocarbon phases by retrograde condensation. Finally, lighter hydrocarbons pooled above the heaviest ones. These mechanisms have been simulated by a numerical model of basin evolution, including a two-phase migration modulus, and by a numerical model of retrograde condensation.« less

Overpressure, Flow Focusing, Compaction and Slope Stability on the continental slope: Insights from IODP Expedition 308

NASA Astrophysics Data System (ADS)

Flemings, P. B.

2010-12-01

Integrated Ocean Drilling Program Expepedition 308 used direct measurements of pore pressure, analysis of hydromechanical properties, and geological analysis to illuminate how sedimentation, flow focusing, overpressure, and slope stability couple beneath the seafloor on the deepwater continental slope in the Gulf of Mexico. We used pore pressure penetrometers to measure severe overpressures (60% of the difference between lithostatic stress and hydrostatic pressure) that extend from the seafloor for 100’s of meters. We ran uniaxial consolidation experiments on whole core and found that although permeability is relatively high near the seafloor, the sediments are highly compressible. As a result, the coefficient of consolidation (the hydraulic diffusivity) is remarkably constant over a large range of effective stresses. This behavior accounts for the high overpressure that begins near the seafloor and extends to depth. Forward modeling suggests that flow is driven laterally along a permeable unit called the Blue Unit. Calculations suggest that soon after deposition, lateral flow lowered the effective stress and triggered the submarine landslides that we observe. Later in the evolution of this system, overpressure may have pre-conditioned the slope to failure by earthquakes. Results from IODP Expedition 308 illustrate how pore pressure and sedimentation control the large-scale form of continental margins, how submarine landslides form, and provide strategies for designing stable drilling programs.

Evaluation of organic matter, subsurface temperature and pressure with regard to gas generation in low-permeability Upper Cretaceous and Lower Tertiary sandstones in Pacific Creek area, Sublette and Sweetwater Counties, Wyoming.

USGS Publications Warehouse

Law, B.E.; Spencer, C.W.; Bostick, N.H.

1980-01-01

The onset of overpressuring occurs at c.3,500 m, near the base of the U. Cretaceous Lance Formation. The development of overpressuring may involve several processes; however, interpretation of the available information indicates that active generation of large amounts of wet gas is one of the more important processes. The present minimum temperature at the top of overpressuring is at least 88oC. The preservation of abnormally high pressures is due to presently active generation of gas in a thick interval of discontinuous, very low-permeability shales, siltstones, and sandstones. - from Authors

Submarine landslides on the north continental slope of the South China Sea

NASA Astrophysics Data System (ADS)

Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping

2018-02-01

Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.

Prediction of sonic boom from experimental near-field overpressure data. Volume 2: Data base construction

NASA Technical Reports Server (NTRS)

Glatt, C. R.; Reiners, S. J.; Hague, D. S.

1975-01-01

A computerized method for storing, updating and augmenting experimentally determined overpressure signatures has been developed. A data base of pressure signatures for a shuttle type vehicle has been stored. The data base has been used for the prediction of sonic boom with the program described in Volume I.

46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-11 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the vapor collection system does not exceed: (i) The maximum design working pressure for the...

46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-11 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the vapor collection system does not exceed: (i) The maximum design working pressure for the...

46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-11 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the vapor collection system does not exceed: (i) The maximum design working pressure for the...

The effect of ignition location on explosion venting of hydrogen-air mixtures

NASA Astrophysics Data System (ADS)

Cao, Y.; Guo, J.; Hu, K.; Xie, L.; Li, B.

2017-07-01

The effect of ignition location and vent burst pressure on the internal pressure-time history and external flame propagation was investigated for vented explosions of hydrogen-air mixtures in a small cylindrical vessel. A high-speed camera was used to record videos of the external flame while pressure transducers were used to record pressure-time histories. It was found that central ignition always leads to the maximum internal peak overpressure, and front ignition resulted in the lowest value of internal peak overpressure. The internal peak overpressures are increased corresponding to the increase in the vent burst pressure in the cases of central and rear ignition. Because of the effect of acoustic oscillations, the phenomenon of oscillations is observed in the internal pressure profile for the case of front ignition. The pressure oscillations for the cases of rear and central ignition are triggered by external explosions. The behavior of flames outside the chamber is significantly associated with the internal pressure of the chamber so that the velocity of the jet flame is closely related to the internal overpressure peak.

The development of shock wave overpressure driven by channel expansion of high current impulse discharge arc

NASA Astrophysics Data System (ADS)

Xiong, Jia-ming; Li, Lee; Dai, Hong-yu; Wu, Hai-bo; Peng, Ming-yang; Lin, Fu-chang

2018-03-01

During the formation of a high current impulse discharge arc, objects near the discharge arc will be strongly impacted. In this paper, a high power, high current gas switch is used as the site of the impulse discharge arc. The explosion wave theory and the arc channel energy balance equation are introduced to analyze the development of the shock wave overpressure driven by the high current impulse discharge arc, and the demarcation point of the arc channel is given, from which the energy of the arc channel is no longer converted into shock waves. Through the analysis and calculation, it is found that the magnitude of the shock wave overpressure caused by impulse discharge arc expansion is closely related to the arc current rising rate. The arc shock wave overpressure will undergo a slow decay process and then decay rapidly. The study of this paper will perform the function of deepening the understanding of the physical nature of the impulse arc discharge, which can be used to explain the damage effect of the high current impulse discharge arc.

AFWL (Air Force Weapons Laboratory) HULL (Hydrodynamics Unlimited) calculations of air blast over a dam slope. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fry, M.A.; Needham, C.E.; Stucker, M.

1976-10-01

This laboratory performed Hydrodynamics Unlimited (HULL) calculations of the air blast over a dam for two yields and two pressure regions. A 5th calculation included a rigid blockhouse at the foot of the dam. Although the shielding effect of the dam reduced the incident blast wave overpressure, reflection of the shock from the valley floor raised the peak overpressure up to at least 40% of the free air value. In almost every case, the overpressure impulses near the foot of the dam were greater than or equal to free air values. The rigid blockhouse experienced the most severe overpressure environments.more » The assumption of a 50-psi hard blockhouse is reasonable. During collapse of the blockhouse, it appears to be rigid to the air flow, since it responds slowly to the rapid air blast. Although there may be other reasons to detonate the weapon on the surface of the reservoir, the best way to destroy the blockhouse and any related structures with air blast, probably would be to detonate the device downstream of the blockhouse.« less

Mitigation Systems for Confined Blast Loading - Crew Protection in Armored Vehicles

DTIC Science & Technology

2009-04-01

Effects of Tungsten Alloy Property Variations on Penetrator Performance for Spaced Armors.” Advances in Powder Metallurgy and Particulate Materials...Table 8.1. Cylinder properties for confined field test. ............................................... 93 Table 8.2. FEM snapshot of the confined...persons or property . Blast mitigation should reduce the overpressure, impulse, fragments, projectile, thermal and toxic hazards that occur during an

Sediment compaction and pore pressure prediction in deepwater basin of the South China Sea: Estimation from ODP and IODP drilling well data

NASA Astrophysics Data System (ADS)

Xie, Yangbing; Wu, Tuoyu; Sun, Jin; Zhang, Hanyu; Wang, Jiliang; Gao, Jinwei; Chen, Chuanxu

2018-02-01

Overpressure in deepwater basins not only causes serious soft sediment deformation, but also significantly affects the safety of drilling operations. Therefore, prediction of overpressure in sediments has become an important task in deepwater oil exploration and development. In this study, we analyze the drilling data from ODP Leg 184 Sites 1144, 1146, and 1148, and IODP Leg 349 Sites U1431, U1432, U1433, and U1435 to study the sediment compaction and controls in the northern South China Sea. Sedimentation rate, sediment content, distribution area, and buried depth are the factors that influence sediment compaction in the deepwater basin of the South China Sea. Among these factors, the sediment content is the most important. The fitted normal compacted coefficients and mudline porosity for an interval of 50 m shows disciplinary variation versus depth. The pore pressure predicted from different fitted results shows varying overpressure situations. The normal compaction trend from Site 1144 reflects the porosity variation trend in stable deposition basins in the northern South China Sea. The predicted pore pressure shows overpressure at Site 1144, which is attributed to compaction disequilibrium. Nevertheless, the mixed lithology column may influence the predicted over-pressure at Site 1148, which is responsible for the confusing result. Above all, we find that sediment compaction should serve as a proxy for pore pressure in the deepwater basin of the South China Sea.

LOX/hydrocarbon rocket engine analytical design methodology development and validation. Volume 2: Appendices

NASA Technical Reports Server (NTRS)

Niiya, Karen E.; Walker, Richard E.; Pieper, Jerry L.; Nguyen, Thong V.

1993-01-01

This final report includes a discussion of the work accomplished during the period from Dec. 1988 through Nov. 1991. The objective of the program was to assemble existing performance and combustion stability models into a usable design methodology capable of designing and analyzing high-performance and stable LOX/hydrocarbon booster engines. The methodology was then used to design a validation engine. The capabilities and validity of the methodology were demonstrated using this engine in an extensive hot fire test program. The engine used LOX/RP-1 propellants and was tested over a range of mixture ratios, chamber pressures, and acoustic damping device configurations. This volume contains time domain and frequency domain stability plots which indicate the pressure perturbation amplitudes and frequencies from approximately 30 tests of a 50K thrust rocket engine using LOX/RP-1 propellants over a range of chamber pressures from 240 to 1750 psia with mixture ratios of from 1.2 to 7.5. The data is from test configurations which used both bitune and monotune acoustic cavities and from tests with no acoustic cavities. The engine had a length of 14 inches and a contraction ratio of 2.0 using a 7.68 inch diameter injector. The data was taken from both stable and unstable tests. All combustion instabilities were spontaneous in the first tangential mode. Although stability bombs were used and generated overpressures of approximately 20 percent, no tests were driven unstable by the bombs. The stability instrumentation included six high-frequency Kistler transducers in the combustion chamber, a high-frequency Kistler transducer in each propellant manifold, and tri-axial accelerometers. Performance data is presented, both characteristic velocity efficiencies and energy release efficiencies, for those tests of sufficient duration to record steady state values.

Sonic boom measurements from accelerating supersonic tracked sleds

NASA Technical Reports Server (NTRS)

Reed, J. W.

1974-01-01

Supersonic sled tests on the Sandia 1524-m (5000-ft) track generate sonic booms of sufficient intensity to allow some airblast measurements at distance scales not obtained from wind tunnel or flight tests. During acceleration, an emitted curved boom wave propagates to a caustic, or focus. Detailed measurements around these caustics may help to clarify the overpressure magnification which can occur from real aircraft operations. Six fixed pressure gages have been operated to document the general noise field, and a mobile array of twelve gages.

Hypervelocity Impact Analysis of International Space Station Whipple and Enhanced Stuffed Whipple Shields

DTIC Science & Technology

2004-12-01

29 Figure 6. Flash Radiography Images of the Debris Cloud and Ejecta...hand, are not predictable. Explosions can occur because of the inadvertent mixing of propellant and oxidizer or the over-pressurization of...residual propellant due to spacecraft heating. Over-pressurized batteries may also cause explosions. Based on statistical analysis of known hypervelocity

Experimental study of hydraulic ram effects on a liquid storage tank: Analysis of overpressure and cavitation induced by a high-speed projectile.

PubMed

Lecysyn, Nicolas; Bony-Dandrieux, Aurélia; Aprin, Laurent; Heymes, Frédéric; Slangen, Pierre; Dusserre, Gilles; Munier, Laurent; Le Gallic, Christian

2010-06-15

This work is part of a project for evaluating catastrophic tank failures caused by impacts with a high-speed solid body. Previous studies on shock overpressure and drag events have provided analytical predictions, but they are not sufficient to explain ejection of liquid from the tank. This study focuses on the hydrodynamic behavior of the liquid after collision to explain subsequent ejection of liquid. The study is characterized by use of high-velocity projectiles and analysis of projectile dynamics in terms of energy loss to tank contents. New tests were performed at two projectile velocities (963 and 1255 m s(-1)) and over a range of viscosities (from 1 to 23.66 mPa s) of the target liquid. Based on data obtained from a high-speed video recorder, a phenomenological description is proposed for the evolution of intense pressure waves and cavitation in the target liquids. Copyright 2010 Elsevier B.V. All rights reserved.

Potential Explosion Hazard of Carbonaceous Nanoparticles: Screening of Allotropes

PubMed Central

Turkevich, Leonid A.; Fernback, Joseph; Dastidar, Ashok G.; Osterberg, Paul

2016-01-01

There is a concern that engineered carbon nanoparticles, when manufactured on an industrial scale, will pose an explosion hazard. Explosion testing has been performed on 20 codes of carbonaceous powders. These include several different codes of SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes) and CNFs (carbon nanofibers), graphene, diamond, fullerene, as well as several different control carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226 protocol), at a concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples typically exhibited overpressures of 5–7 bar, and deflagration index KSt = V1/3 (dP/dt)max ~ 10 – 80 bar-m/s, which places these materials in European Dust Explosion Class St-1. There is minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with primary particle size (BET specific surface area). PMID:27468178

THE INTERNAL STRUCTURE OF OVERPRESSURED, MAGNETIZED, RELATIVISTIC JETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martí, J. M.; Perucho, M.; Gómez, J. L.

This work presents the first characterization of the internal structure of overpressured, steady superfast-magnetosonic relativistic jets in connection with their dominant type of energy. To this aim, relativistic magnetohydrodynamic simulations of different jet models threaded by a helical magnetic field have been analyzed covering a wide region in the magnetosonic Mach number–specific internal energy plane. The merit of this plane is that models dominated by different types of energy (internal energy: hot jets; rest-mass energy: kinetically dominated jets; magnetic energy: Poynting-flux-dominated jets) occupy well-separated regions. The analyzed models also cover a wide range of magnetizations. Models dominated by the internalmore » energy (i.e., hot models, or Poynting-flux-dominated jets with magnetizations larger than but close to one) have a rich internal structure characterized by a series of recollimation shocks and present the largest variations in the flow Lorentz factor (and internal energy density). Conversely, in kinetically dominated models, there is not much internal or magnetic energy to be converted into kinetic, and the jets are featureless with small variations in the flow Lorentz factor. The presence of a significant toroidal magnetic field threading the jet produces large gradients in the transversal profile of the internal energy density. Poynting-flux-dominated models with high magnetization (≈10 or larger) are prone to be unstable against magnetic pinch modes, which sets limits on the expected magnetization in parsec-scale active galactic nucleus jets or constrains their magnetic field configuration.« less

Corrosion Mitigation Strategies - an Introduction

DTIC Science & Technology

2009-02-05

formed • Stress corrosion cracking Leaders in Corrosion Control Technology • Overpressure • Pressure of a gas over a liquid- solubility of gases in...Power surges • Crack protective films, fretting, fatique Design – Chemistry • Used to eliminate candidate materials • pH acidic (H+) basic (OH...Technology • Laboratory tests • Published data Mechanical Properties • Strength • Ductility • Environmental cracking Methods of Corrosion Control–Materials

Porcine head response to blast.

PubMed

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

2012-01-01

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

Porcine Head Response to Blast

PubMed Central

Shridharani, Jay K.; Wood, Garrett W.; Panzer, Matthew B.; Capehart, Bruce P.; Nyein, Michelle K.; Radovitzky, Raul A.; Bass, Cameron R. ‘Dale’

2012-01-01

Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposes porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110 to 740 kPa peak incident overpressure with scaled durations from 1.3 to 6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. Instrumentation was placed on the porcine head to measure bulk acceleration, pressure at the surface of the head, and pressure inside the cranial cavity. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within 30 s and the remaining two recovered within 8 min following respiratory assistance and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80 to 390 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300–2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385 to 3845 G’s and were well correlated with peak incident overpressure (R2 = 0.90). One SD corridors for the surface pressure, intracranial pressure (ICP), and head acceleration are presented to provide experimental data for computer model validation. PMID:22586417

An Experimental Study of Unconfined Hydrogen/Oxygen and Hydrogen/Air Explosions

NASA Technical Reports Server (NTRS)

Richardson, Erin; Skinner, Troy; Blackwood, James; Hays, Michael; Bangham, Mike; Jackson, Austin

2014-01-01

Development tests are being conducted to characterize unconfined Hydrogen/air and Hydrogen/Oxygen blast characteristics. Most of the existing experiments for these types of explosions address contained explosions, like shock tubes. Therefore, the Hydrogen Unconfined Combustion Test Apparatus (HUCTA) has been developed as a gaseous combustion test device for determining the relationship between overpressure, impulse, and flame speed at various mixture ratios for unconfined reactions of hydrogen/oxygen and hydrogen/air. The system consists of a central platform plumbed to inject and mix component gasses into an attached translucent bag or balloon while monitoring hydrogen concentration. All tests are ignited with a spark with plans to introduce higher energy ignition sources in the future. Surrounding the platform are 9 blast pressure "Pencil" probes. Two high-speed cameras are used to observe flame speed within the combustion zone. The entire system is raised approx. 6 feet off the ground to remove any ground reflection from the measurements. As of this writing greater than 175 tests have been performed and include Design of Experiments test sets. Many of these early tests have used bags or balloons between approx. 340L and approx. 1850L to quantify the effect of gaseous mixture ratio on the properties of interest. All data acquisition is synchronized between the high-speed cameras, the probes, and the ignition system to observe flame and shock propagation. Successful attempts have been made to couple the pressure profile with the progress of the flame front within the combustion zone by placing a probe within the bag. Overpressure and impulse data obtained from these tests are used to anchor engineering analysis tools, CFD models and in the development of blast and fragment acceleration models.

Large eddy simulation and experimental study on vented gasoline-air mixture explosions in a semi-confined obstructed pipe.

PubMed

Li, Guoqing; Du, Yang; Wang, Shimao; Qi, Sheng; Zhang, Peili; Chen, Wenzhuo

2017-10-05

In this work, LES simulation coupled with a TFC sub-grid combustion model has been performed in a semi-confined pipe (L/D=10, V=10L) in the presence of four hollow-square obstacles (BR=49.8%) with circular hollow cross-section, in order to study the premixed gasoline-air mixture explosions. The comparisons between simulated results and experimental results have been conducted. It was found that the simulated results were in good agreement with experimental data in terms of flame structures, flame locations and overpressure time histories. Moreover, the interaction between flame propagation process and obstacles, overpressure dynamics were analyzed. In addition, the effects of initial gasoline vapor concentration (lean (ϕ=1.3%), stoichiometric (ϕ=1.7%) and rich (ϕ=2.1%)), and the number of obstacles (from 1 to 4) were also investigated by experiments. Some of the experimental results have been compared with the literature data. It is found that the explosion parameters of gasoline-air mixtures (e.g. the maximum overpressure peaks, average overpressure growth rates, etc.) are different from some other fuels such as hydrogen, methane and LPG, etc. Copyright © 2017. Published by Elsevier B.V.

Overpressure, Low Effective Stress, and Slope Failure in the Ursa Region, Deep-Water Gulf of Mexico

NASA Astrophysics Data System (ADS)

Sawyer, D. E.; Flemings, P. B.

2004-12-01

Slope failures are associated with overpressured pore fluids and low effective stresses in the Quaternary strata of the Ursa Region, deep-water Gulf of Mexico. At Ursa, a permeable turbidite sandstone (the Blue Unit) is overlain by a low-permeability mudstone. Overpressure in the mudstone, measured with a pore pressure penetrometer (piezoprobe), begin within a few meters of the seafloor and extend 250-450 meters down to the Blue Unit. The overpressure ratio (λ *=(Pp-Phydrostatic)\\ (Sv-Phydrostatic), where Sv is the overburden stress, Pp is pore pressure, and Phydrostatic is the hydrostatic pressure) ranges from 0.8 where the overburden is thin to 0.4 where the overburden is thick. Detachment surfaces, mapped with high resolution 3D seismic data, are associated with zones where effective stresses are low. Four subsurface slumps were mapped and are oriented generally northwest-southeast. Slump surface areas are less than 250 km2 and maximum scarp-wall height on the largest slide is ˜120 meters. We interpret that asymmetric loading of the Blue Unit by low-permeable mudstone has driven fluids to where overburden is thin, decreased effective stress, and generated slope instability.

Container/Closure Integrity Testing and the Identification of a Suitable Vial/Stopper Combination for Low-Temperature Storage at -80 {degrees}C.

PubMed

Zuleger, Brigitte; Werner, Uwe; Kort, Alexander; Glowienka, Rene; Wehnes, Engelbert; Duncan, Derek

2012-01-01

It was recently found that after storage of a live viral vaccine at -80 °C in glass vials closed with rubber stoppers, a phenomenon was revealed which had not been observed before with other viral products stored at -20 °C: overpressure in the vials. As this phenomenon poses a serious safety problem for medical personnel as well as for the product itself, an investigation was initiated to identify the root cause of the overpressure. After exclusion of possible root causes (differences in air temperature or atmospheric air pressure during filling and quality control testing, outgassing from the formulation buffer) the remaining hypothesis involved a possible container closure integrity issue at low temperature. The glass transition temperatures (T(g)) of many rubber stopper formulations are in the range -55 to -70 °C. At storage temperatures below T(g), the rubber stopper loses its elastic properties and there is a risk that the seal integrity of the vial could be compromised. Loss of seal integrity of the vials near storage temperatures of -80 °C would result in an ingress of cold dense gas into the vial headspace. After removal of the vials from storage at -80 °C, the rubber stoppers could regain their elastic properties and the vials would quickly reseal, thereby trapping the ingressed gas, which leads to overpressure in the vial headspace. Nondestructive laser-based headspace analysis was used to investigate the maintenance of container closure integrity as a function of the filling and capping/crimping process, storage and transport conditions, and vial/stopper designs. This analytical method is based on frequency modulation spectroscopy (FMS) and can be used for noninvasive headspace measurements of headspace pressure and headspace gas composition. Changes in the vial headspace composition and/or pressure are a clear marker for vials that have lost container closure integrity. After storage of a live viral vaccine at -80 °C in glass vials closed with rubber stoppers, overpressure in some of the vials was observed, posing a serious safety problem for medical personnel as well as for the product. A working hypothesis to explain this phenomenon involved a possible container closure integrity issue at these low temperatures. The glass transition temperatures (T(g)) of many rubber stopper formulations are in the range -55 to -70 °C. At storage temperatures below T(g), the rubber stopper loses its elastic properties, resulting in compromised seal integrity of the vial and ingress of cold dense gas into the vial headspace. Upon thawing, the rubber stoppers regain their elastic properties and the vials quickly reseal, thereby trapping the ingressed gas, which leads to overpressure in the vial headspace. Nondestructive, laser-based headspace analysis, which is able to detect changes in headspace pressure and gas composition, was used to investigate the maintenance of container closure integrity. Changes in the vial headspace composition and/or pressure are a clear marker for vials that have lost container closure integrity.

How can fluid overpressures be developed and maintained in crustal fault zones ?

NASA Astrophysics Data System (ADS)

LECLÈRE, H.; Cappa, F.; Faulkner, D. R.; Armitage, P. J.; Blake, O. O.; Fabbri, O.

2013-12-01

The presence of fluid overpressure in crustal fault zones is known to play a key role on the stability of faults and it has often been invoked to explain the triggering of earthquakes and the apparent weakness of misoriented faults. However, the mechanisms allowing the development and maintenance of fluid overpressures in fault remain unresolved. We investigate how fluid overpressures can be developed and maintained in complex fault zones with hydraulic and elastic heterogeneities. Here we address this question combining geological observations, laboratory experiments and hydromechanical models of an active crustal fault zone in the Ubaye-Argentera area (southeastern France). The fault zone studied is located in the Argentera external crystalline massif and is connected to regional NW-SE steeply-dipping dextral strike-slip faults with an offset of several kilometers. The fault zone cuts through migmatitic gneisses composed of quartz, K-feldspar, plagioclase, biotite and muscovite. It exposes several anastomosing core zones surrounded by damage zones with a pluri-decametric total width. The core zones are made up of centimetric to pluridecimetric phyllosilicate-rich gouge layers while the damage zones are composed of pluri-metric phyllonitic rock derived from mylonite. The determination of fault structure in the field and its hydraulic and mechanical properties in the lab are key aspects to improve our understanding of the role of fluids in fault mechanics and earthquake triggering. Here, the permeability and elastic moduli of the host rock, damage zone and fault core were measured from natural plugs with a diameter of 20 mm and lengths between 26 to 51 mm, using a high-pressure hydrostatic fluid-flow apparatus. Measurements were made with confining pressures ranging from 30 to 210 MPa and using argon pore fluid pressure of 20 MPa. Data show a reduction of the permeability values of one order of magnitude between host rock and fault damage zone and a decrease of 50% of the elastic properties between host rock and core zone. Data also show a higher dependence of the permeability on the effective pressure for the host rock compared with the damage zone and core zone. This heterogeneity of properties is related to the development of different microstructures such as microcracks, S-C structures and microbreccia across the fault zone achieved during the tectonic history of the fault. From these physical property values and the fault zone architecture, we then analyzed the effects of sudden mechanical loading approximating to static normal-stress transfer following an earthquake on a neighbouring fault, on the development of fluid overpressures. A series of 1-D hydromechanical numerical models was used to show that sudden normal stress increase is a viable mechanism for fluid overpressuring in the studied fault-zone. The models also showed that fluid overpressures can be temporarily maintained in the studied fault zone and that the maintenance of fluid overpressures is controlled by the structure and fluid-flow properties of the fault zone.

Pyrotechnic hazards classification and evaluation program. Phase 3, segments 1-4: Investigation of sensitivity test methods and procedures for pyrotechnic hazards evaluation and classification, part A

NASA Technical Reports Server (NTRS)

1971-01-01

The findings, conclusions, and recommendations relative to the investigations conducted to evaluate tests for classifying pyrotechnic materials and end items as to their hazard potential are presented. Information required to establish an applicable means of determining the potential hazards of pyrotechnics is described. Hazard evaluations are based on the peak overpressure or impulse resulting from the explosion as a function of distance from the source. Other hazard classification tests include dust ignition sensitivity, impact ignition sensitivity, spark ignition sensitivity, and differential thermal analysis.

Data acquisition from blast overpressure trials

NASA Astrophysics Data System (ADS)

Kirk, D. R.

1993-03-01

A Macintosh computer has been used to acquire data from blast overpressure trials on various weapons. The computer is connected to a multiple channel FM data recorder via a MacSCS1488 bus controller, allowing the computer to control the recorder and to acquire data from it through an analog to digital converter. Detailed instructions are given for connecting the hardware and operating the software involved.

Analysis of the Explosive Internal Impact on the Barriers of Building Structures

NASA Astrophysics Data System (ADS)

Siwiński, Jarosław; Stolarski, Adam

2017-10-01

Work issues concern the safety of construction in relation to the hazards arising from explosion of the explosive charge located inside the building. The algorithms proposed in the paper for determining the parameters of the overpressure wave resulting from the detonation of clustered explosive charges, determine the basis for numerical simulation analyzes. Determination of the maximum value of peak pressure on the wave forehead of an internal explosion is presented on the basis of reflected wave analysis. Changeability in time of the internal explosion action describes the overpressure phase only. The analysis of the load caused by the internal explosive charge detonation was carried out under conditions of the undisturbed standard atmosphere. A load determination algorithm has been developed, taking into account the geometrical characteristics of the building barriers and the rooms as well as the parameters of environment in which the detonation occurs. The way of taking into account the influence of venting surfaces, i.e. windows, doors, ventilation ducts, on the overpressure wave parameters, was presented. Discloses a method to take into account the effect of the surface relief, i.e. windows, doors, air ducts, pressure wave parameters. Modification of the method for explosive overpressure determination presented by Cormie, Smith, Mays (2009), was proposed in the paper. This modification was developed on the basis of substitute impulse analysis for multiple overpressure pulses. In order to take into account the pressure distribution of explosive gases on the barrier surface, the method of modification the relationship for determination the changeability over time and space of the pressure of explosive gases, was presented. For this purpose, the changeability of the pressure wave angles of incidence to the barrier and the distance of the explosive charge to any point on the surface of the barrier, was taken into account. Based on the developed procedure, the overpressure changeability over time was determined for selected measurement points of the reference room. A comparative analysis of the determined loadings with experimental results and theoretical results of other authors, taken from the original work of Weerhiejm et al. (2012), was carried out.

Modelling hydrothermal venting in volcanic sedimentary basins: Impact on hydrocarbon maturation and paleoclimate

NASA Astrophysics Data System (ADS)

Iyer, Karthik; Schmid, Daniel W.; Planke, Sverre; Millett, John

2017-06-01

Vent structures are intimately associated with sill intrusions in sedimentary basins globally and are thought to have been formed contemporaneously due to overpressure generated by gas generation during thermogenic breakdown of kerogen or boiling of water. Methane and other gases generated during this process may have driven catastrophic climate change in the geological past. In this study, we present a 2D FEM/FVM model that accounts for 'explosive' vent formation by fracturing of the host rock based on a case study in the Harstad Basin, offshore Norway. Overpressure generated by gas release during kerogen breakdown in the sill thermal aureole causes fracture formation. Fluid focusing and overpressure migration towards the sill tips results in vent formation after only few tens of years. The size of the vent depends on the region of overpressure accessed by the sill tip. Overpressure migration occurs in self-propagating waves before dissipating at the surface. The amount of methane generated in the system depends on TOC content and also on the type of kerogen present in the host rock. Generated methane moves with the fluids and vents at the surface through a single, large vent structure at the main sill tip matching first-order observations. Violent degassing takes place within the first couple of hundred years and occurs in bursts corresponding to the timing of overpressure waves. The amount of methane vented through a single vent is only a fraction (between 5 and 16%) of the methane generated at depth. Upscaling to the Vøring and Møre Basins, which are a part of the North Atlantic Igneous Province, and using realistic host rock carbon content and kerogen values results in a smaller amount of methane vented than previously estimated for the PETM. Our study, therefore, suggests that the negative carbon isotope excursion (CIE) observed in the fossil record could not have been caused by intrusions within the Vøring and Møre Basins alone and that a contribution from other regions in the NAIP is also required to drive catastrophic climate change.

Sonic boom measurement test plan for Space Shuttle STS-3 reentry

NASA Technical Reports Server (NTRS)

Henderson, H. R.

1982-01-01

The lateral area from the reentry ground track affected by sonic boom overpressure levels is determined. Four data acquisition stations are deployed laterally to the STS-3 reentry flight track. These stations provide six intermediate band FM channels of sonic boom data, universal time synchronization, and voice annotation. All measurements are correlated with the vehicle reentry flight track information along with atmospheric and vehicle operation conditions.

Two-phase flow visualization under reservoir conditions for highly heterogeneous conglomerate rock: A core-scale study for geologic carbon storage.

PubMed

Kim, Kue-Young; Oh, Junho; Han, Weon Shik; Park, Kwon Gyu; Shinn, Young Jae; Park, Eungyu

2018-03-20

Geologic storage of carbon dioxide (CO 2 ) is considered a viable strategy for significantly reducing anthropogenic CO 2 emissions into the atmosphere; however, understanding the flow mechanisms in various geological formations is essential for safe storage using this technique. This study presents, for the first time, a two-phase (CO 2 and brine) flow visualization under reservoir conditions (10 MPa, 50 °C) for a highly heterogeneous conglomerate core obtained from a real CO 2 storage site. Rock heterogeneity and the porosity variation characteristics were evaluated using X-ray computed tomography (CT). Multiphase flow tests with an in-situ imaging technology revealed three distinct CO 2 saturation distributions (from homogeneous to non-uniform) dependent on compositional complexity. Dense discontinuity networks within clasts provided well-connected pathways for CO 2 flow, potentially helping to reduce overpressure. Two flow tests, one under capillary-dominated conditions and the other in a transition regime between the capillary and viscous limits, indicated that greater injection rates (potential causes of reservoir overpressure) could be significantly reduced without substantially altering the total stored CO 2 mass. Finally, the capillary storage capacity of the reservoir was calculated. Capacity ranged between 0.5 and 4.5%, depending on the initial CO 2 saturation.

Chemical osmosis, reverse chemical osmosis, and the origin of subsurface brines

NASA Astrophysics Data System (ADS)

Graf, Donald L.

1982-08-01

Calculations using recently-tabulated values of density and osmotic coefficient for NaCl-H 2O indicate that overpressuring is more than adequate to overcome chemical osmosis and drive reverse chemical osmosis in sedimentary sequences. The best-demonstrated overpressuring mechanism is the rapid deposition of fine-grained sediments. The dehydration of gypsum contributes to overpressuring for brief time intervals at shallow depths, whereas water evolved during the protracted conversion of smectite to illite is probably a subordinate, but continuing contributor to overpressuring at greater depth. Occurrences of overpressuring in sedimentary sections older than Cretaceous indicate that post-depositional mechanisms such as tectonic compression and aquathermal pressuring must also operate. The latter may be of major importance in geothermal areas with adequate low-permeability seals, and a nontrivial contributor in areas of normal geothermal gradient because of shales that sharply decrease normal fluid flow. The strongest arguments for the importance to present-day brine compositions of membrane concentration of sea-water solutes are (1) the correlation of δD values of water molecules of pore fluid with those of local meteoric water, (2) the need for major sources of Mg 2+ and Cl - in apparently evaporite-free basins. Even where dissolution of halite is a major contributor of solute, reverse chemical osmosis still operates to leak relatively dilute water. Of the associated diagenetic chemical reactions, that of Mg 2+ with limestone to form dolomite is particularly effective in generating concentrated Cl - brines rich in Ca 2+. It decreases the concentration of Mg 2+, increases that of Ca 2+, and decreases those of both SO 42- and CO 32- by precipitating CaCO 3 and CaSO 4 because of the Ca 2+ common-ion effect.

Occupational overpressure exposure of breachers and military personnel

NASA Astrophysics Data System (ADS)

Kamimori, G. H.; Reilly, L. A.; LaValle, C. R.; Olaghere Da Silva, U. B.

2017-11-01

Military and law enforcement personnel may be routinely and repetitively exposed to low-level blast (LLB) overpressure during training and in operations. This repeated exposure has been associated with symptoms similar to that reported for sports concussion. This study reports LLB exposure for various military and law enforcement sources in operational training environments. Peak overpressure and impulse data are presented from indoor breaching, outdoor breaching, shotgun door breaching, small arms discharge, and mortar and artillery fire missions. Data were collected using the Black Box Biometrics (B3) Blast Gauge sensors. In all cases, sensors were attached to the operators and, where possible, also statically mounted to walls or other fixed structures. Peak overpressures from below 1 psi (7 kPa) to over 12 psi (83 kPa) were recorded; all values reported are uncorrected for incidence angle to the blast exposure source. The results of these studies indicate that the current minimum safe distance calculations are often inaccurate for both indoor and outdoor breaching scenarios as true environmental exposure can consistently exceed the 4 psi (28 kPa) incident safe threshold prescribed by U.S. Army doctrine. While ballistic (shotgun) door breaching and small arms firing only expose the operator to low peak exposure levels, the sheer number of rounds fired during training may result in an excessive cumulative exposure. Mortar and artillery crew members received significantly different overpressure and impulse exposures based on their position (job) relative to the weapon. As both the artillery and mortar crews commonly fire hundreds of rounds during a single training session they are also likely to receive high cumulative exposures. These studies serve to provide the research community with estimates for typical operator exposure across a range of operational scenarios or in the discharge of various weapons systems.

CONCEPTUAL MODEL FOR ORIGIN OF ABNORMALLY PRESSURED GAS ACCUMULATIONS IN LOW-PERMEABILITY RESERVOIRS.

USGS Publications Warehouse

Law, B.E.; Dickinson, W.W.

1985-01-01

The paper suggests that overpressured and underpressured gas accumulations of this type have a common origin. In basins containing overpressured gas accumulations, rates of thermogenic gas accumulation exceed gas loss, causing fluid (gas) pressure to rise above the regional hydrostatic pressure. Free water in the larger pores is forced out of the gas generation zone into overlying and updip, normally pressured, water-bearing rocks. While other diagenetic processes continue, a pore network with very low permeability develops. As a result, gas accumulates in these low-permeability reservoirs at rates higher than it is lost. In basins containing underpressured gas accumulations, rates of gas generation and accumulation are less than gas loss. The basin-center gas accumulation persists, but because of changes in the basin dynamics, the overpressured accumulation evolves into an underpressured system.

Peak Overpressures for Internal Blast

DTIC Science & Technology

1979-06-01

fuels that also are oxygen- deficient (trinitrotoluene ( TNT ), for example), the initial detonation is followed by combustion in an afterburn ; it is...and consequently show lesser afterburn effects. Figure 8 shows overpressures for reference internal explo- sions with TNT , an oxygen-deficient...excplosive (oxygen balance of -14% to C02 and -257 to CO) 8 with pronounced afterburn effects that depend on the TNT -air ratio. Shown for compari- soa are

Design Concepts for Hardened Communications Structures

DTIC Science & Technology

1990-03-01

air . Based on this background, a family of structures was designed that can protect whip and directional antennae from the blast and shock effects from...Ground Surface Air Overpressure with Range, 1-MT Weapon, HOB - 0 and 500 ft ........................................... 25 5 Positive Phase Duration...design included the crater size, the e*eca field, airblast, and ground shock for ground surface air overpressure levels ranging from :5,000 to 500 psi. As

Investigation of the Explosive Potential of the Hybrid Propellant Combinations N2O4/PBAN and CTF/PBAN

DTIC Science & Technology

1967-03-01

nitrogen tetroxide (N„0 ) and polybutadyne-aluminum (PBAN), and chlorine trifluoride (CTF) and PBAN. This program consisted of a series of eight...explosive potential of two hybrid propellant combinations; nitrogen tetroxide QLOL) and polybutadyne - aluminum (PBAN) and chlorine triflouride (CTF...or positive-phase impulse yield. FREE AIR OVERPRESSURE: (OR FREE FIELD OVERPRESSURE): The unreflected pressure, in excess of the ambient atmospheric

Undesirable leakage to overlying formations with horizontal and vertical injection wells

NASA Astrophysics Data System (ADS)

Mosaheb, M.; Zeidouni, M.

2017-12-01

Deep saline aquifers are considered for underground storage of carbon dioxide. Undesirable leakage of injected CO2 to adjacent layers would disturb the storage process and can pollute shallower fresh water resources as well as atmosphere. Leaky caprocks, faults, and abandoned wells are examples of leaky pathways. In addition, the overpressure can reactivate a sealing fault or damage the caprock layer. Pressure management is applicable during the storage operation to avoid these consequences and to reduce undesirable leakage.The fluids can be injected through horizontal wells with a wider interval than vertical wells. Horizontal well injection would make less overpressure by delocalizing induced pressure especially in thin formations. In this work, numerical and analytical approaches are applied to model different leaky pathways with horizontal and vertical injection wells. we compare leakage rate and overpressure for horizontal and vertical injection wells in different leaky pathway systems. Results show that the horizontal well technology would allow high injection rates with lower leakage rate for leaky well, leaky fault, and leaky caprock cases. The overpressure would reduce considerably by horizontal well comparing to vertical well injection especially in leaky fault system. The horizontal well injection is an effective method to avoid reaching to threshold pressure of fault reactivation and prevent the consequent induced seismicity.

Development and analysis of a leak-based blast attenuator and scaling laws for primary blast peak overpressure for a large caliber muzzleloaded cannon

NASA Astrophysics Data System (ADS)

Carson, Robert Andrew

One of the primary aspects of the research and development work carried out at Benet Laboratories is the Soldier. Maintenance of their health in the field is the first priority while the second priority is the enhancement of their performance. Therefore, a new concept for a weapon system that targets these two priorities is highly desirable. This is the case with a new concept that can reduce the peak overpressure without the use of a muzzle device for a muzzle loaded cannon system. Such a novel concept was developed in this thesis through the application of propellant leak into the precursor region, i.e., when the projectile is still in the bore. A 3D hydrocode (ALE3D) was employed to predict the blast overpressure for the baseline and propellant leak configurations. However, a 3D hydrocode is computationally very expensive to predict peak overpressure in the far-field and an efficient method to predict peak overpressure in the far-field is of significance. Therefore, scaling laws for primary blast peak overpressure were also developed in this thesis. Initially, two propellant leak concepts were examined. A bulge leak method and a channel leak method, which were compared to the baseline configuration. The initial channel leak configuration (referred to as CLM-1) significantly reduced the exit pressure ratio during projectile ejection, and thereby, resulted in a weaker blast. This in-turn substantially attenuated the peak overpressure to the rear of the muzzle without the aid of a muzzle device while having a marginal loss in the projectile exit velocity. For CLM-1, at one monitored location with the largest peak overpressure, a reduction of about 38% in peak overpressure was observed as compared to the baseline case. In order to compare different leak configurations, a performance metric was defined by comparing the ratio of peak overpressure and projectile exit velocity for a leak configuration to that for the baseline configuration. This metric was referred to as the Figure of Merit (FoM) and defined for any probe location. An average FoM was also defined based on the average of local FoM over different locations/probes. The greater the FoM is above zero, the better the configuration. The average FoM for the CLM-1 configuration was 0.221. In addition to FoM, shock structure and strength were also analyzed for the bulge and channel configurations at both the precursor and blast stages. With the success of the CLM-1 configuration, we then performed a parametric study of the channel leak geometry and examined the effect of different geometric parameters on peak overpressure attenuation. The idea was to further improve the performance of the channel leak method. We divided our parametric study into five groups (i.e., A through E), referred to as CLM-A through CLM-E configurations. The focus in these five groups was on geometric parameters that were expected to be the most influential or relevant. Three relevant geometric parameters were considered in this work. In groups A and B, we focused on channel leak volume. Group C analyzed the effect of channel length while groups D and E investigated the effect of aspect ratio. The five groups were ordered in this way because we anticipated the total leak volume to be the most influential parameter, then the channel length which was followed by the aspect ratio. The total leak volume of 7.5% resulted in a relatively high average FoM. On the other hand, the use of channels with a shorter length was found to be detrimental while a lower value of aspect ratio was beneficial. Three leak configurations of CLM-A1, CLM-E1 and CLM-E2 provided excellent peak overpressure attenuation (i.e., above 45% and up to 63%). Each led to an average FoM above 0.5 while CLM-E configurations resulted in lower local FoM for probes near the muzzle and higher FoM for probes farther from the muzzle, and thus, a higher variation of FoM over the probes. The average FoM based on the far-field probes was about 0.575 and 0.560 for CLM-E1 and CLM-E2, respectively, and 0.520 for CLM-A1. Blast structure and strength were also analyzed for these three configurations. In the last part of this thesis, we focused on the baseline and CLM-A1 configurations in order to develop scaling laws for the primary blast peak overpressure. Two different power-law scaling techniques were considered. In the first power-law, scaling parameters were defined from the muzzle center. The second power-law scaling was defined based on the blast center. The muzzle center based power-law has been used in the past while the blast center based power-law is a newly developed scaling law in this thesis. For the baseline configuration, both scaling laws performed well and for many locations absolute difference was below 10%. For the CLM-A1 configuration, blast center based power-law predictions were better than those from the muzzle center based power-law and showed a better overall correlation with the ALE3D predictions.

Exploration of the molecular basis of blast injury in a biofidelic model of traumatic brain injury

NASA Astrophysics Data System (ADS)

Thielen, P.; Mehoke, T.; Gleason, J.; Iwaskiw, A.; Paulson, J.; Merkle, A.; Wester, B.; Dymond, J.

2018-01-01

Biological response to blast overpressure is complex and results in various and potentially non-concomitant acute and long-term deficits to exposed individuals. Clinical links between blast severity and injury outcomes remain elusive and have yet to be fully described, resulting in a critical inability to develop associated protection and mitigation strategies. Further, experimental models frequently fail to reproduce observed physiological phenomena and/or introduce artifacts that confound analysis and reproducibility. New models are required that employ consistent mechanical inputs, scale with biological analogs and known clinical data, and permit high-throughput examination of biological responses for a range of environmental and battlefield- relevant exposures. Here we describe a novel, biofidelic headform capable of integrating complex biological samples for blast exposure studies. We additionally demonstrate its utility in detecting acute transcriptional responses in the model organism Caenorhabditis elegans after exposure to blast overpressure. This approach enables correlation between mechanical exposure and biological outcome, permitting both the enhancement of existing surrogate and computational models and the high-throughput biofidelic testing of current and future protection systems.

Laboratory investigation of coupled deformation and fluid flow in mudrock: implications for slope stability in the Ursa Basin, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Flemings, P. B.; Song, I.; Saffer, D. M.

2012-04-01

Integrated Ocean Drilling Program (IODP) Expedition 308 was dedicated to the study of fluid flow, overpressure, and slope stability in the Ursa Basin, on the continental slope of the Gulf of Mexico. In this location, turbidite channel levees deposited a wedge-shaped body: the deposition rate in the thick part of the wedge exceeded 12 mm/yr. This rapid deposition of fine grained sediments generated excess pore pressure observed near the seafloor. IODP drilling focused on three Sites: U1322, U1323, and U1324, along the steepest slope (2°) on the eastern section of the Ursa Canyon levee deposits. In this study, we conducted a suite of deformation experiments on samples from Site 1324, to understand the stress-strain behavior and stress history of the recovered core material. Our samples were taken from depths of 30-160 meters below seafloor, and are composed of ~40% silt and ~60% clay, with porosities ranging from ~42-55%. We first conducted uniaxial consolidation tests to determine pre-consolidation stresses and define deformation behavior due to simulated vertical loading. In a subset of tests, we subjected the samples to undrained shearing following consolidation, to define the friction angle and define relationships between stress state and deformation. We find that the lateral effective stress during uniaxial compression is 56-64% of the vertical effective stress (avg. K0=0.6). Pre-consolidation stresses suggest that pore pressure is hydrostatic to 50 mbsf (meters below seafloor), and is overpressured below this, with excess pressures up to 70% of the hydrostatic effective vertical stress (λ*=0.7) at 160 mbsf. The time coefficient of consolidation (cv) in these experiments is ~2.2x10-8 m2/s. Undrained shear tests define a failure envelope with a residual friction angle (φ) of 23° and zero cohesion. In our shearing tests, we observed no pore pressure change during initial (primarily elastic) shear deformation, but note a monotonic increase in pore pressure during the later plastic shear deformation, possibly due to re-organization of sediment grains. Our consolidated undrained tests suggest that the slope in the study area should remain stable during sedimentation, despite the high overpressure (λ*=0.7). However, this stress condition could be affected by gravitational and seepage forces that cause horizontal extension along the slope. In this case, a reduction in horizontal confining stress would render the slope sediments unstable (drive them to active failure) as defined by the Coulomb criterion. If shear strain during slope failure leads to plastic deformation of the sediments, this would also induce a pore pressure increase, further decreasing the factor of safety (FS) for landslides. For the landslides of the slope (i.e., FS=1.0), the overpressure rate λ* should reach 0.92 for the given slope (2°). However, active normal faulting takes place at lower values of λ* (0.2-0.8). Our analysis suggests that the instability of the slope may arise more likely from normal faults dipping stiff (45°+φ/2) than from landslides slipping on a plane parallel to such a gentle slope of seafloor.

An experimental study of perforated muzzle brakes

NASA Astrophysics Data System (ADS)

Dillon, R. E., Jr.; Nagamatsu, H. T.

1984-06-01

A firing test was conducted to examine the recoil efficiency and blast characteristics of perforated muzzle brakes fitted to a 20 mm cannon. Recoil impulse blast overpressures, muzzle velocity, sequential spark shadowgraphs, and photographs of the muzzle flash structure were obtained. Three different nuzzle devices were used with one device equipped with pressure transducers to measure the static pressure in the brake. Experimental results are compared with the earlier predictions of Dillon and Nagamatsu.

Apollo 13 Case Study

NASA Technical Reports Server (NTRS)

Anderson, Brenda Lindley

2011-01-01

The dramatic journey of the crippled Apollo 13 vehicle has been heavily documented and popularized. Many people know there was an explosion in the service module which caused the vehicle to lose its oxygen supply. Less well known is the set of circumstances which led to the explosion. This paper examines the manufacturing, processing and testing history of oxygen tank #2, detailing the additive effects which caused the oxygen to ignite and to overpressure the tank.

The effects of strong shock waves on mortality rates and percentages of pulmonary lesions in rats as a function of the number of exposures

NASA Technical Reports Server (NTRS)

Vassout, P.; Parmentier, G.

1978-01-01

The results of the study reveal that with regard to the pulmonary lesions, twice the number of exposures is compensated for by quartering the overpressure of the wave crest. With regard to the mortality rates, it reveals that halving the overpressure of the wave crest is offset by a 20-fold increase in the number of exposures.

MEASUREMENT OF FREE AIR ATOMIC BLAST PRESSURES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haskell, N.A.; Fava, J.A.; Brubaker, R.M.

1958-02-14

BS>Peak free-air overpressure versus time measurements in the 10-to-2 psi range were obtained as a function of distance directly over a nuclear burst at a low scaled height. This information was to be used to establish the points in space at which the reflected and direct shock waves merge into a single shock wave and to determine the overpressure as a function of distance for the merged wave, in support of drone-aircraft lethal-volume studies. It was also desired to obtain free air peak overpressure versus distance measurements for an atomic burst at a high altitude. Data are tabulated that weremore » obtained by deploying, from a B-29 aircraft, 10 parachute-borne instrumented canisters on each shot. The second objective was achieved by deploying 15 parachute-borne canisters from the strike aircraft on one shot. (C.H.)« less

Thermodynamically consistent model of brittle oil shales under overpressure

NASA Astrophysics Data System (ADS)

Izvekov, Oleg

2016-04-01

The concept of dual porosity is a common way for simulation of oil shale production. In the frame of this concept the porous fractured media is considered as superposition of two permeable continua with mass exchange. As a rule the concept doesn't take into account such as the well-known phenomenon as slip along natural fractures, overpressure in low permeability matrix and so on. Overpressure can lead to development of secondary fractures in low permeability matrix in the process of drilling and pressure reduction during production. In this work a new thermodynamically consistent model which generalizes the model of dual porosity is proposed. Particularities of the model are as follows. The set of natural fractures is considered as permeable continuum. Damage mechanics is applied to simulation of secondary fractures development in low permeability matrix. Slip along natural fractures is simulated in the frame of plasticity theory with Drucker-Prager criterion.

Impact of the volume of rooms on shock wave propagation within a multi-chamber system

NASA Astrophysics Data System (ADS)

Julien, B.; Sochet, I.; Vaillant, T.

2016-03-01

The behavior of a shock wave generated by a hemispherical gaseous charge and propagating within a confined multi-chamber system is analyzed through the evolution of some of the shock parameters (maximum overpressure and positive impulse). The influence of a variation in the volume of the rooms on the pressure history inside the building is also studied. Several small-scale experiments have been carried out using an adjustable model representative of a pyrotechnic workshop. The experimental results show that the pressure histories are very complex. Yet, using a global approach, we were able to link the evolution of the arrival time of the shock wave within the building with the reference obtained in the free field. New parameters were developed to best fit the experimental maximal overpressure in the cells and in the corridor leading to two predictive laws used to estimate the maximal overpressure in the model.

Submarine slope failures due to pipe structure formation.

PubMed

Elger, Judith; Berndt, Christian; Rüpke, Lars; Krastel, Sebastian; Gross, Felix; Geissler, Wolfram H

2018-02-19

There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barber, A.J.; Tjokrosapoetro, S.; Charlton, T.R.

In Timor, eastern Indonesia, where the northern margin of the Australian continent is colliding with the Banda Arc, Australian continental margin sediments are being incorporated into an imbricate wedge, which passes northward into a foreland fold and thrust belt. Field mapping in Timor has shown that scale clays, containing irregularly shaped or phacoidal blocks (up to several meters long) and composed of a wide range of lithologies derived from local stratigraphic units, occur in three environments: along wrench faults, as crosscutting shale diapirs, and associated with mud volcanoes. A model is proposed linking these phenomena. Shales become overpressured as amore » result of overthrusting; this overpressure is released along vertical wrench faults, which cut through the overthrust units; overpressured shales containing blocks of consolidated units rise along the fault zones as shale diapirs; and escaping water, oil, and gas construct mud volcanoes at the surface. 6 figures, 1 table.« less

METHOD FOR PUMPING GASES AT LOW VACUUM PRESSURES

DOEpatents

Milleron, N.

1962-06-01

A method is given for pumping overpressure "pulses" or "bursts" of gases without a significant rise in base pressure within a "gettering-type" vacuum pump having surfaces within the pumping cavity coated with or comprising clean gettering metal, e.g., Mo or Ta. The cavity is first pumped down by any convenient means to an equilibrium base pressure in the range desired, generally below 10/sup -6/ mm Hg. At this pressure, the metal immediately adsorbs overpressures or "bursts" of gases striking same with thermal motion without raising the base pressure significantiy. Desorption takes place at an equilibrium rate which, of course, is dependent upon the equilibrium pressure, and such desorbed gases are continuously removed by diffuaion pump or other pumping, whereby said overpressures or "bursts" of gases are removed without a rise in the equilibrium pressure and/or back diffusion of the gaseous pulse from the pumping cavity. (AEC)

Drainage Asperities on Subduction Megathrusts

NASA Astrophysics Data System (ADS)

Sibson, R. H.

2012-12-01

Geophysical observations coupled with force-balance analyses suggest that the seismogenic shear zone interface of subduction megathrusts is generally fluid-overpressured to near-lithostatic values (λv = Pf/σv > 0.9) below the forearc hanging-wall, strongly modulating the profile of frictional shear resistance. Fluid sources include the accretionary prism at shallow levels and, with increasing depth, metamorphic dehydration of material entrained within the subduction shear zone together with progressive metamorphism of oceanic crust in the downgoing slab. Solution transfer in fine-grained material contained within the deeper subduction shear zone (150 < T < 350°C) likely contributes to hydrothermal sealing of fractures. A dramatic difference may therefore exist between low prefailure permeability surrounding the megathrust and high postfailure fracture permeability along the rupture zone and adjacent areas of aftershock activity. Observed postseismic changes in the velocity structure of the fore-arc hanging-wall led Husen and Kissling (2001) to propose massive fluid loss across the subduction interface following the 1995 Antofagasta, Chile, Mw8.0 megathrust rupture. Such trans-megathrust discharges represent a variant of 'fault-valve' action in which the subduction interface itself acts as a seal trapping overpressured fluids derived from metamorphic dehydration beneath. In low-permeability assemblages the maximum sustainable overpressure is limited by the activation or reactivation of brittle faults and fractures under the prevailing stress state. Highest overpressures tend to occur at low differential stress in compressional stress regimes. Loci for fluid discharge are likely determined by stress heterogeneities along the megathrust (e.g. the hangingwall of the rupture at its downdip termination). Discharge sites may be defined by swarm aftershocks defining activated fault-fracture meshes. However, fluid loss across a subduction interface will be enhanced when the stress-state in the forearc hanging-wall switches from compressional reverse-slip faulting before failure to extensional normal-slip faulting postfailure, as occurred during the 2011 Mw9.0 Tohoku megathrust rupture. Mean stress and fault-normal stress then change from being greater than vertical stress prefailure, to less than vertical stress postfailure. Postfailure reductions in overpressure are expected from a combination of poroelastic effects and fluid loss through fault-fracture networks, enhancing vertical permeability. Mineralised fault-fracture meshes in exhumed fore-arc assemblages (e.g. the Alaska-Juneau Au-quartz vein swarm) testify to the episodic discharge of substantial volumes of hydrothermal fluid (< tens of km3). Localized drainage from the subduction interface shear zone increases frictional strength significantly, giving rise to a postfailure strength asperities. Anticipated strength increases from such fluid discharge depends on the magnitude of the drop in overpressure but are potentially large (< hundreds of MPa). Time to the subsequent failure is then governed by reaccumulation of fluid overpressure as well as shear stress along the subduction interface.

Design of Rail Instrumentation for Wind Tunnel Sonic Boom Measurements and Computational-Experimental Comparisons

NASA Technical Reports Server (NTRS)

Cliff, Susan E.; Elmiligui, A.; Aftosmis, M.; Morgenstern, J.; Durston, D.; Thomas, S.

2012-01-01

An innovative pressure rail concept for wind tunnel sonic boom testing of modern aircraft configurations with very low overpressures was designed with an adjoint-based solution-adapted Cartesian grid method. The computational method requires accurate free-air calculations of a test article as well as solutions modeling the influence of rail and tunnel walls. Specialized grids for accurate Euler and Navier-Stokes sonic boom computations were used on several test articles including complete aircraft models with flow-through nacelles. The computed pressure signatures are compared with recent results from the NASA 9- x 7-foot Supersonic Wind Tunnel using the advanced rail design.

Application of ultrasound in electrochemistry. An overview of mechanisms and design of experimental arrangement.

PubMed

Klima, J

2011-02-01

An overview of possible mechanisms by which sonication can influence electrochemical processes is given. Four mechanisms are discussed: – acoustic streaming; – microstreaming and turbulence due to cavitation; – formation of microjets in the course of collapse of cavitation bubble; – shock waves; and possible effects are illustrated on several examples. The most effective process is formation of microjets,which can not only decrease diffusion layer thickness under 1 lm, but also activate (depassivate) electrode surface. Design of experimental arrangement with maximum participation of microjets is proposed. Two approaches are proposed: – focusing of ultrasound on the working electrode and reduction of energy losses by over-pressure; – ‘‘tuning” the reactor to obtain resonance, i.e. formation of stationary waves by activating reactor in itsresonant mode. Copyright © 2010 Elsevier B.V. All rights reserved.

Results of steel containment vessel model test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luk, V.K.; Ludwigsen, J.S.; Hessheimer, M.F.

A series of static overpressurization tests of scale models of nuclear containment structures is being conducted by Sandia National Laboratories for the Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission. Two tests are being conducted: (1) a test of a model of a steel containment vessel (SCV) and (2) a test of a model of a prestressed concrete containment vessel (PCCV). This paper summarizes the conduct of the high pressure pneumatic test of the SCV model and the results of that test. Results of this test are summarized and are compared with pretest predictions performed bymore » the sponsoring organizations and others who participated in a blind pretest prediction effort. Questions raised by this comparison are identified and plans for posttest analysis are discussed.« less

High Pressure Hydrogen Pressure Relief Devices: Accelerated Life Testing and Application Best Practices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgess, Robert M.; Post, Matthew B.; Buttner, William J.

Pressure relief devices (PRDs ) are used to protect high pressure systems from burst failure caused by overpressurization. Codes and standards require the use of PRDs for the safe design of many pressurized systems. These systems require high reliability due to the risks associated with a burst failure. Hydrogen service can increase the risk of PRD failure due to material property degradation caused by hydrogen attack. The National Renewable Energy Laboratory (NREL) has conducted an accelerated life test on a conventional spring loaded PRD. Based on previous failures in the field, the nozzles specific to these PRDs are of particularmore » interest. A nozzle in a PRD is a small part that directs the flow of fluid toward the sealing surface to maintain the open state of the valve once the spring force is overcome. The nozzle in this specific PRD is subjected to the full tensile force of the fluid pressure. These nozzles are made from 440C material, which is a type of hardened steel that is commonly chosen for high pressure applications because of its high strength properties. In a hydrogen environment, however, 440C is considered a worst case material since hydrogen attack results in a loss of almost all ductility and thus 440C is prone to fatigue and material failure. Accordingly, 440C is not recommended for hydrogen service. Conducting an accelerated life test on a PRD with 440C material provides information on necessary and sufficient conditions required to produce crack initiation and failure. The accelerated life test also provides information on other PRD failure modes that are somewhat statistically random in nature.« less

Prediction of sonic boom from experimental near-field overpressure data. Volume 1: Method and results

NASA Technical Reports Server (NTRS)

Glatt, C. R.; Hague, D. S.; Reiners, S. J.

1975-01-01

A computerized procedure for predicting sonic boom from experimental near-field overpressure data has been developed. The procedure extrapolates near-field pressure signatures for a specified flight condition to the ground by the Thomas method. Near-field pressure signatures are interpolated from a data base of experimental pressure signatures. The program is an independently operated ODIN (Optimal Design Integration) program which obtains flight path information from other ODIN programs or from input.

Volcano infrasonic signals and magma degassing: First-order experimental insights and application to Stromboli

NASA Astrophysics Data System (ADS)

Lane, Stephen J.; James, Mike R.; Corder, Steven B.

2013-09-01

We demonstrate the rise and expansion of a gas slug as a fluid dynamic source mechanism for infrasonic signals generated by gas puffing and impulsive explosions at Stromboli. The fluid dynamics behind the rise, expansion and burst of gas slugs in the confines of an experimental tube can be characterised into different regimes. Passive expansion occurs for small gas masses, where negligible dynamic gas over-pressure develops during bubble ascent and, prior to burst, meniscus oscillation forms an important infrasonic source. With increasing gas mass, a transition regime emerges where dynamic gas over-pressure is significant. For larger gas masses, this regime transforms to fully explosive behaviour, where gas over-pressure dominates as an infrasonic source and bubble bursting is not a critical factor. The rate of change of excess pressure in the experimental tube was used to generate synthetic infrasonic waveforms. Qualitatively, the waveforms compare well to infrasonic waveforms measured from a range of eruptions at Stromboli. Assuming pressure continuity during flow through the vent, and applying dimensionless arguments from the first-order experiments, allows estimation of eruption metrics from infrasonic signals measured at Stromboli. Values of bubble length, gas mass and over-pressure calculated from infrasonic signals are in excellent agreement with those derived by independent means for eruptions at Stromboli, therefore providing a method of estimating eruption metrics from infrasonic measurement.

Numerical simulation of mechanical compaction of deepwater shallow sediments

NASA Astrophysics Data System (ADS)

Sun, Jin; Wu, Shiguo; Deng, Jingen; Lin, Hai; Zhang, Hanyu; Wang, Jiliang; Gao, Jinwei

2018-02-01

To study the compaction law and overpressure evolution in deepwater shallow sediments, a large-strain compaction model that considers material nonlinearity and moving boundary is formulated. The model considers the dependence of permeability and material properties on void ratio. The modified Cam-Clay model is selected as the constitutive relations of the sediments, and the deactivation/reactivation method is used to capture the moving top surface during the deposition process. A one-dimensional model is used to study the compaction law of the shallow sediments. Results show that the settlement of the shallow sediments is large under their own weight during compaction. The void ratio decreases strictly with burial depth and decreases more quickly near the seafloor than in the deeper layers. The generation of abnormal pressure in the shallow flow sands is closely related to the compaction law of shallow sediments. The two main factors that affect the generation of overpressure in the sands are deposition rate and permeability of overlying clay sediments. Overpressure increases with an increase in deposition rate and a decrease in the permeability of the overlying clay sediment. Moreover, an upper limit for the overpressure exists. A two-dimensional model is used to study the differential compaction of the shallow sediments. The pore pressure will still increase due to the inflow of the pore fluid from the neighboring clay sediment even though the deposition process is interrupted.

Protection of the lung from blast overpressure by stress wave decouplers, buffer plates or sandwich panels.

PubMed

Sedman, Andrew; Hepper, A

2018-03-19

This paper outlines aspects of UK Ministry of Defence's research and development of blast overpressure protection technologies appropriate for use in body armour, with the aim of both propagating new knowledge and updating existing information. Two simple models are introduced not only to focus the description of the mechanism by which the lungs can be protected, but also to provide a bridge between fields of research that may hold the key to further advances in protection technology and related body armour. Protection can be provided to the lungs by decoupling the stress wave transmission into the thorax by managing the blast energy imparted through the protection system. It is proposed that the utility of the existing 'simple decoupler' blast overpressure protection is reviewed in light of recent developments in the treatment of those sustaining both overpressure and fragment injuries. It is anticipated that further advances in protection technology may be generated by those working in other fields on the analogous technologies of 'buffer plates' and 'sandwich panels'. © Crown copyright (2018), Dstl. This material is licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gsi.gov.uk.

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

PubMed

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

2012-01-01

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

Interim Tests of the Effects of Long Duration Blast-Type FLows on Fires in Urban Interiors and Contents of Emergency Operating Centers (EOC)

DTIC Science & Technology

1976-01-01

orifices A,f and A„ respectively) were conducted, all at a (.ornpression chamber overpressure of about 2 psi. During the current testing program, an...actually reflect a pressure decrease with time derived from the modified exponencial relationship given in Eq. 2-14. Blast Flow vs. LDFF Flow Through...indicating the presence of strong eddies and counter currents . »"JCüat^Liöt -r*"- aK.m.ju.J’ aBBtflbsSii ^’ :•.. ’ ä l 1 2 \\ 2 Lzi .3

Near-Sea Floor Compaction and Shallow Overpressures: Constrains From High Strain Consolidation Tests on ODP Sediments

NASA Astrophysics Data System (ADS)

Olgaard, D. L.; Dugan, B. E.; Gooch, M. J.

2001-12-01

Before launching into the title topic, I will share a few ``memories of torsion testing'' that exemplify one of the breakthrough contributions Mervyn Paterson has made to Geodynamics. Mervyn and his machines, the torsion apparatus in particular, have revolutionized structural geology by providing the means to quantify crustal and mantle deformation processes up to and beyond the high shear strains observed in the field. High strain is also important in basin evolution. High strain consolidation tests are used to help understand mechanical and fluid flow processes in deforming sediments on continental slopes. Clay-rich sediments compact from 70% to less than 40% porosity within 1000m below the sea floor [mbsf]. Clay-rich sediments have notoriously low permeabilities and, when combined with rapid deposition rates, can cause pore-fluid pressures greatly in excess of hydrostatic at shallow depths. Such high overpressures are particularly hazardous to slope stability and to deepwater drilling. Recently, Dugan and Flemings [Science, 289, 2000] used forward sedimentation models for the New Jersey continental slope calibrated with ODP data, to predict fluid pressures near lithostatic to depths of 640m. In the current study we use consolidation tests to verify these model predictions. Silty-clay cores were collected from depths of 60 to 650mbsf during ODP Leg 1073. Five samples were tested under drained, uniaxial strain conditions, i.e. zero radial displacement. Cylindrical samples were first subjected to a hydrostatic effective stress of ~0.2MPa, then axially loaded at a constant rate of 0.7kPa/min to maintain drained conditions. Pore pressure [brine] was held constant at 3.5MPa. Confining pressure was increased to maintain the uniaxial strain condition. P-wave velocities and permeabilities were measured at various stress conditions on two samples. The samples compacted rapidly at low stresses, then at decreasing rates as stress increased. A total compaction of 22% volumetric strain was achieved at the maximum axial stress of 22 MPa. The in situ pore pressures for each depth were calculated from the ``maximum effective stress'' determined from the break in slope of the data in log[effective stress] vs. void ratio plots. Test results confirm that pore pressure gradients exceed hydrostatic, approaching lithostatic, from about 60m to the base of the Pleistocene [~550m], then decrease within the underlying Miocene sandy silt. The confining-to-axial effective stress ratio increased asymptotically during loading to a value of 0.6; similar to that expected for silty shales. P-wave velocity-porosity-effective stress trends are used to predict overpressures, and thus anticipate hazards in near-seafloor sediments.

Shockwave Interaction with a Cylindrical Structure

NASA Astrophysics Data System (ADS)

Mulligan, Phillip

2017-06-01

An increased understanding of the shockwave interaction with a cylindrical structure is the foundation for developing a method to explosively seal a pipe similar to the Deepwater Horizon accident in the Gulf of Mexico. Shockwave interactions with a cylindrical structure have been a reoccurring focus of energetics research. Some of the most notable contributions of non-destructive tests are described in ``The Effects of Nuclear Weapons'' (Glasstone, 1962). The work presented by Glasstone examines shockwave interaction from a 20-megaton bomb with a cylindrical structure. However, the data is limited to a peak overpressure of less than 25 psi, requiring several miles between the structure and the charge. The research presented in the following paper expands on the work Glasstone described by examining the shockwaves from 90, 180, and 270-gram C-4 charges interacting with a 6-inch diameter cylindrical structure positioned 52-inches from the center of the charge. The three charge weights that were tested in this research generated a peak overpressures of approximately 15, 25, and 40 psi, respectively. This research examines the peak pressure and total impulse from each charge acting on the cylindrical structure as well as the formation of vortices on the ``backside'' of the cylinder surface. This paper describes the methodology and findings of this study as well as examines the causality and implications of its results on our understanding of the shockwave interaction with a cylindrical structure.

Origin of Slope Failure in the Ursa Region, Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Stigall, J.; Dugan, B.

2008-12-01

We use one-dimensional fluid flow and stability models to predict the evolution of overpressure and stability conditions of IODP Expedition Sites U1322 and U1324 in the Ursa region, northern Gulf of Mexico. Simulations of homogenous mud deposited at 3 and 12 mm/yr for Sites U1322 and U1324, with permeability (k) on the order of 10-17m2 and bulk compressibility of .4 /MPa, predict overpressures up to .45MPa and 1MPa in shallow sediments (<200m below sea floor). With limit equilibrium calculations for an infinite slope, these overpressures equate to a factor of safety (FS) greater than 10 and 4.5 for a internal friction angle of 26° and a seafloor slope of 2°. This implies stability throughout the last 50,000 years. Seismic and core observations, however, document major slope failures that span the entire Ursa region. Permeability in this region is well constrained by laboratory experiments, so we investigate how pulsed (high-to-low) sedimentation rates could have created unstable conditions, FS <1. Models with periods of high sedimentation generate overpressure that create unstable conditions while maintaining the time-averaged sedimentation rates. Other factors which are not possible to simulate in one dimension, such as a complex basin geometry, also influence the conditions that caused the past failures. A two-dimensional model linking lateral flow between the sites with the interpreted geometry from seismic stratigraphy gives a better picture of the flow field and instability within the basin. Asymmetrical loading of permeable sediments could have created a lateral difference in pore pressures which would have driven lateral flow from Site U1324 to Site U1322 where overpressures are higher than our one-dimensional models suggest. We anticipate that two-dimensional models with transient sedimentation patterns will enhance our understanding of flow in marginally stable environments and triggers of slope failures in passive margin systems.

Large Scale Flame Spread Environmental Characterization Testing

NASA Technical Reports Server (NTRS)

Clayman, Lauren K.; Olson, Sandra L.; Gokoghi, Suleyman A.; Brooker, John E.; Ferkul, Paul V.; Kacher, Henry F.

2013-01-01

Under the Advanced Exploration Systems (AES) Spacecraft Fire Safety Demonstration Project (SFSDP), as a risk mitigation activity in support of the development of a large-scale fire demonstration experiment in microgravity, flame-spread tests were conducted in normal gravity on thin, cellulose-based fuels in a sealed chamber. The primary objective of the tests was to measure pressure rise in a chamber as sample material, burning direction (upward/downward), total heat release, heat release rate, and heat loss mechanisms were varied between tests. A Design of Experiments (DOE) method was imposed to produce an array of tests from a fixed set of constraints and a coupled response model was developed. Supplementary tests were run without experimental design to additionally vary select parameters such as initial chamber pressure. The starting chamber pressure for each test was set below atmospheric to prevent chamber overpressure. Bottom ignition, or upward propagating burns, produced rapid acceleratory turbulent flame spread. Pressure rise in the chamber increases as the amount of fuel burned increases mainly because of the larger amount of heat generation and, to a much smaller extent, due to the increase in gaseous number of moles. Top ignition, or downward propagating burns, produced a steady flame spread with a very small flat flame across the burning edge. Steady-state pressure is achieved during downward flame spread as the pressure rises and plateaus. This indicates that the heat generation by the flame matches the heat loss to surroundings during the longer, slower downward burns. One heat loss mechanism included mounting a heat exchanger directly above the burning sample in the path of the plume to act as a heat sink and more efficiently dissipate the heat due to the combustion event. This proved an effective means for chamber overpressure mitigation for those tests producing the most total heat release and thusly was determined to be a feasible mitigation strategy to incorporate into the microgravity experiment.

Computational Model of the Eye for Primary and Secondary Blast Trauma

DTIC Science & Technology

2015-10-01

inflicted closed eye injuries with features similar to those seen in patients with ocular blast trauma. Alphonse et al. [16] studied the effect of low...Kemper, V. Alphonse , C. McNally, I. Herring, P. Brown, J. Stitzel, and S. Duma. Response of Porcine Eyes to Blast Overpressure: Effects of Overpressure...that induces closed globe anterior and posterior pole damage. Experimental eye research, 99:63–70, 2012. [16] V. D. Alphonse , A. R. Kemper, B. T. Strom

Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

NASA Astrophysics Data System (ADS)

Haering, Edward A.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

2006-05-01

The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

NASA Technical Reports Server (NTRS)

Haering, Edward A., Jr.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

2005-01-01

The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

Aspect ratios and magma overpressures of non-feeder dikes observed in the Miyake-jima volcano (Japan), and fracture toughness of its upper part

NASA Astrophysics Data System (ADS)

Kusumoto, Shigekazu; Geshi, Nobuo; Gudmundsson, Agust

2013-03-01

present a new method for estimating the length and maximum thickness (aperture) of a dike from the observed opening at one dike tip. We apply the method to 15 arrested non-feeder dikes (where the upper tip is known, the lower tip unknown) in the caldera walls of Miyake-jima, Japan, to estimate the length-thickness ratio, as well as the magma overpressure and fracture toughness. The calculated length-thickness ratio ranges from 61 to 246, with an average of 136. The ratios are low because the dikes are emplaced close to the surface in comparatively compliant (soft) rocks. Using these ratios and the appropriate elastic constants, the calculated magmatic overpressures of the dikes are between 2.3 and 8.9 MPa, and the stress intensity factors between 38 and 117 MPa m1/2. All these values are within the range of typical in situ estimates, supporting the validity of this new method.

Water Deluge Test at Pad 39B

NASA Image and Video Library

2018-05-24

About 450,000 gallons of water flow at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test on May 24, 2018, at Launch Pad 39B at NASA's Kennedy Space Center in Florida. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was performed by Exploration Ground Systems to confirm the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

Wet Flow Test at Launch Complex 39B

NASA Image and Video Library

2017-12-20

About 450,000 gallons of water flowed at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test at Launch Pad 39B at NASA's Kennedy Space Center in Florida. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was a milestone to confirm and baseline the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

Explosive materials equivalency, test methods and evaluation

NASA Technical Reports Server (NTRS)

Koger, D. M.; Mcintyre, F. L.

1980-01-01

Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

Water Flow Test at Launch Complex 39B

NASA Image and Video Library

2017-12-20

Water flowed during a test at Launch Complex 39B at NASA’s Kennedy Space Center in Florida. About 450,000 gallons of water flowed at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test at Launch Complex 39B. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was a milestone to confirm and baseline the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

Fault-controlled development of shallow hydrothermal systems: Structural and mineralogical insights from the Southern Andes

NASA Astrophysics Data System (ADS)

Roquer, T.; Arancibia, G.; Rowland, J. V.; Iturrieta, P. C.; Morata, D.; Cembrano, J. M.

2017-12-01

Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we conducted meso-microstructural analysis and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). A total of 107 fractures in both exposures were analyzed. The ATF specific segment shows two tectonic solutions that can be modeled as Andersonian and non-Andersonian tectonic regimes: (1) shear (mode II/III) failure occurs at differential stresses > 28 MPa and fluid pressures < 40-80% lithostatic in the Andersonian regime; and (2) sporadic hybrid extensional + shear (modes I + II/III) failure occurs at differential stresses < 20 MPa and anomalously high fluid pressures > 85-98% lithostatic in the non-Andersonian regime. Additionally, the LOFS exposure cyclically fails in extension (mode I) or extension + shear (modes I + II/III) in the Andersonian regime, at differential stresses < 28 MPa and fluid pressures > 40-80% lithostatic. In areas of spatial interaction between ATF and LOFS, these conditions might favor: (1) the storage of overpressured fluids in hydrothermal systems associated with the ATF faults, and (2) continuous fluid flow through vertical conduits in the LOFS faults. These observations suggest that such intersections are highly probable locations for concentrated hydrothermal activity, which must be taken into consideration for further geothermal exploration. ACKNOWLEDGEMENTS. PhD CONICYT grants, Centro de Excelencia en Geotermia de los Andes (CEGA-FONDAP/CONICYT Project #15090013), FONDECYT Project #1130030 and Project CONICYT REDES #140036.

Subjective response to sonic booms having different shapes, rise times, and durations

NASA Technical Reports Server (NTRS)

Mccurdy, David A.

1994-01-01

Two laboratory experiments were conducted to quantify the subjective response of people to simulated outdoor sonic booms having different pressure signatures. The specific objectives of the experiments were to compare subjective response to sonic booms when described in terms of 'loudness' and 'annoyance'; to determine the ability of various noise metrics to predict subjective response to sonic booms; to determine the effects on subjective response of rise time, duration, and level; and to compare the subjective response to 'N-wave' sonic boom signatures with the subjective response to 'minimized' sonic boom signatures. The experiments were conducted in a computer-controlled, man-rated sonic boom simulator capable of reproducing user-specified pressure signatures for a wide range of sonic boom parameters. One hundred and fifty sonic booms representing different combinations of two wave shapes, four rise times, seven durations, and three peak overpressures were presented to 36 test subjects in each experiment. The test subjects in the first experiment made judgments of 'loudness' while the test subjects in the second experiment judged 'annoyance.' Subjective response to sonic booms was the same whether expressed in terms of loudness or in terms of annoyance. Analyses of several different noise metrics indicated that A-weighted sound exposure level and Perceived Level were the best predictors of subjective response. Further analyses indicated that, of these two noise metrics, only Perceived Level completely accounted for the effects of wave shape, rise time, and peak overpressure. Neither metric fully accounted for the effect of duration. However, the magnitude of the duration effect was small over the very wide range of durations considered.

A Case Study of the Failure on Apollo 13: Based on TMX-65270, Report of Apollo 13 Review Board

NASA Technical Reports Server (NTRS)

Anderson, Brenda Lindley

2011-01-01

The dramatic journey of the crippled Apollo 13 vehicle has been heavily documented and popularized. Many people know there was an explosion in the service module which caused the vehicle to lose its oxygen supply. Less well known is the set of circumstances which led to the explosion. This paper examines the manufacturing, processing and testing history of oxygen tank #2, detailing the additive effects which caused the oxygen to ignite and to overpressure the tank.

Design and testing of low sonic boom configurations and an oblique all-wing supersonic transport

NASA Technical Reports Server (NTRS)

Lee, Christopher A.

1995-01-01

From December 1991 to June 1992, applied aerodynamic research support was given to the team working on Low Sonic Boom configurations in the RAC branch at NASA Ames Research Center. This team developed two different configurations: a conventional wing-tail and a canard wing, in an effort to reduce the overpressure of shock waves and the accompanying noise which are projected to the ground from supersonic civil transport aircraft. A generic description of this sensitive technology is given.

The Effect of Propellant Composition on Secondary Muzzle Blast Overpressure

DTIC Science & Technology

1983-04-01

LOVA propellants evaluated included PU/HMX, CTBN /HMX, HTPB/HMX, CAB/RDX, CA/RDX, Kraton/RDX, and EC/NC/RDX. Details of the propellant compositions...RDX tests. Secondary flash was observed for all the firings of all the other candidates, even CTBN /HMX, which had some suppressant. All of these...Propellant Flame Temp (K) Intensity (Mcd) Observations of Flash Kraton/RDX 2283 18.2 ± 1 . 2 11 11 CTBN /HMX 2379 13.8 ± • 72 8 8 HTPB/HMX 2363 10.5

Infrared Imagery of Solid Rocket Exhaust Plumes

NASA Technical Reports Server (NTRS)

Moran, Robert P.; Houston, Janice D.

2011-01-01

The Ares I Scale Model Acoustic Test program consisted of a series of 18 solid rocket motor static firings, simulating the liftoff conditions of the Ares I five-segment Reusable Solid Rocket Motor Vehicle. Primary test objectives included acquiring acoustic and pressure data which will be used to validate analytical models for the prediction of Ares 1 liftoff acoustics and ignition overpressure environments. The test article consisted of a 5% scale Ares I vehicle and launch tower mounted on the Mobile Launch Pad. The testing also incorporated several Water Sound Suppression Systems. Infrared imagery was employed during the solid rocket testing to support the validation or improvement of analytical models, and identify corollaries between rocket plume size or shape and the accompanying measured level of noise suppression obtained by water sound suppression systems.

Sub-lethal Ocular Trauma (SLOT): Establishing a Standardized Blast Threshold to Facilitate Diagnostic, Early Treatment, and Recovery Studies for Blast Injuries to the Eye and Optic Nerve

DTIC Science & Technology

2014-09-01

the less, we observed 64 a broad array of ocular injuries. Petras et al. (1997) observed a similar trend in rats exposed to overpressures of...2013. PMID: 22185582. Petras , J.M., Bauman, R.A., and Elsayed, N.M., 1997, Visual system degeneration induced by blast overpressure: Toxicology...2012, Primary blast injury to the eye and orbit: Finite element modeling: Investigative Ophthalmology: v. 53, pp. 8057–8066. Sanchez, R., Martin , R

Method for Estimating the Sonic-Boom Characteristics of Lifting Canard-Wing Aircraft Concepts

NASA Technical Reports Server (NTRS)

Mack, Robert J.

2005-01-01

A method for estimating the sonic-boom overpressures from a conceptual aircraft where the lift is carried by both a canard and a wing during supersonic cruise is presented and discussed. Computer codes used for the prediction of the aerodynamic performance of the wing, the canard-wing interference, the nacelle-wing interference, and the sonic-boom overpressures are identified and discussed as the procedures in the method are discussed. A canard-wing supersonic-cruise concept was used as an example to demonstrate the application of the method.

The use of loop-seals for the control of the overpressures in hydraulic transients evolving in a sea service water system

NASA Astrophysics Data System (ADS)

Canetta, D.; Capozza, A.; Iovino, G.

The transient response following pump trip-offs and start-ups was investigated in the sea water system of a nuclear power plant. Specific care was devoted to water column separation and cavity collapse phenomena. A computer program designed for analysis of complex hydraulic networks was used. It is found that dangerous overpressures can be avoided by the use of loop seals. The design of the vacuum breaker valves of the loop seals and the optimization of overall transient behavior is discussed.

Laboratory simulation of cratering on small bodies

NASA Technical Reports Server (NTRS)

Schmidt, Robert M.

1991-01-01

A new technique using external pressure was developed to simulate the lithostatic pressure due to self-gravity of small bodies. A 13-in. diameter cylindrical test chamber with L/D of 1 was fabricated to accommodate firing explosive charges with gas overpressures of up to 6000 psi. The chamber was hydrotested to 9000 psi. The method allows much larger scale factors that can be obtained with existing centrifuges and has the correct spherical geometry of self gravity. A simulant for jointed rock to be used in this fixture was developed using weakly cemented basalt. Various strength/pressure scaling theories can now be examined and tested.

Computational Fluid Dynamics Study on the Effects of RATO Timing on the Scale Model Acoustic Test

NASA Technical Reports Server (NTRS)

Nielsen, Tanner; Williams, B.; West, Jeff

2015-01-01

The Scale Model Acoustic Test (SMAT) is a 5% scale test of the Space Launch System (SLS), which is currently being designed at Marshall Space Flight Center (MSFC). The purpose of this test is to characterize and understand a variety of acoustic phenomena that occur during the early portions of lift off, one being the overpressure environment that develops shortly after booster ignition. The SLS lift off configuration consists of four RS-25 liquid thrusters on the core stage, with two solid boosters connected to each side. Past experience with scale model testing at MSFC (in ER42), has shown that there is a delay in the ignition of the Rocket Assisted Take Off (RATO) motor, which is used as the 5% scale analog of the solid boosters, after the signal to ignite is given. This delay can range from 0 to 16.5ms. While this small of a delay maybe insignificant in the case of the full scale SLS, it can significantly alter the data obtained during the SMAT due to the much smaller geometry. The speed of sound of the air and combustion gas constituents is not scaled, and therefore the SMAT pressure waves propagate at approximately the same speed as occurs during full scale. However, the SMAT geometry is much smaller allowing the pressure waves to move down the exhaust duct, through the trench, and impact the vehicle model much faster than occurs at full scale. To better understand the effect of the RATO timing simultaneity on the SMAT IOP test data, a computational fluid dynamics (CFD) analysis was performed using the Loci/CHEM CFD software program. Five different timing offsets, based on RATO ignition delay statistics, were simulated. A variety of results and comparisons will be given, assessing the overall effect of RATO timing simultaneity on the SMAT overpressure environment.

Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bronowski, D.R.; Madsen, M.M.

The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in threemore » orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.« less

The measurement of intracranial pressure and brain displacement due to short-duration dynamic overpressure loading

NASA Astrophysics Data System (ADS)

Iwaskiw, A. S.; Ott, K. A.; Armiger, R. S.; Wickwire, A. C.; Alphonse, V. D.; Voo, L. M.; Carneal, C. M.; Merkle, A. C.

2018-01-01

The experimental measurement of biomechanical responses that correlate with blast-induced traumatic brain injury (bTBI) has proven challenging. These data are critical for both the development and validation of computational and physical head models, which are used to quantify the biomechanical response to blast as well as to assess fidelity of injury mitigation strategies, such as personal protective equipment. Therefore, foundational postmortem human surrogate (PMHS) experimental data capturing the biomechanical response are necessary for human model development. Prior studies have measured short-duration pressure transmission to the brain (Kinetic phase), but have failed to reproduce and measure the longer-duration inertial loading that can occur (Kinematic phase). Four fully instrumented PMHS were subjected to short-duration dynamic overpressure in front-facing and rear-facing orientations, where intracranial pressure (ICP), global head kinematics, and brain motion (as measured by high-speed X-ray) with respect to the skull were recorded. Peak ICP results generally increased with increased dose, and a mirrored pressure response was seen when comparing the polarity of frontal bone versus occipital bone ICP sensors. The head kinematics were delayed when compared to the pressure response and showed higher peak angles for front-facing tests as compared to rear-facing. Brain displacements were approximately 2-6 mm, and magnitudes did not change appreciably between front- and rear-facing tests. These data will be used to inform and validate models used to assess bTBI.

Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

2018-05-01

Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase flow generated during explosive particle dispersal indicates that the particle momentum flux is the dominant term in the near field. Both the gas and particle loading must be taken into account when determining the damage to nearby structures following the detonation of a high-explosive charge surrounded by a material layer.

Modelling Pre-eruptive Progressive Damage in Basaltic Volcanoes: Consequences for the Pre-eruptive Process

NASA Astrophysics Data System (ADS)

Got, J. L.; Amitrano, D.; Carrier, A.; Marsan, D.; Jouanne, F.; Vogfjord, K. S.

2017-12-01

At Grimsvötn volcano, high-quality earthquake and continuous GPS data were recorded by the Icelandic Meteorological Office during its 2004-2011 inter-eruptive period and exhibited remarkable patterns : acceleration of the cumulated earthquake number, and a 2-year exponential decrease in displacement rate followed by a 4-year constant inflation rate. We proposed a model with one magma reservoir in a non-linear elastic damaging edifice, with incompressible magma and a constant pressure at the base of the magma conduit. We first modelled seismicity rate and damage as a function of time, and show that Kachanov's elastic brittle damage law may be used to express the decrease of the effective shear modulus with time. We then derived simple analytical expressions for the magma reservoir overpressure and the surface displacement as a function of time. We got a very good fit of the seismicity and surface displacement data by adjusting only three phenomenological parameters and computed magma reservoir overpressure, magma flow and strain power as a function of time. Overpressure decrease is controlled by damage and shear modulus decrease. Displacement increases, although overpressure is decreasing, because shear modulus decreases more than overpressure. Normalized strain power reaches a maximum 0.25 value. This maximum is a physical limit, after which the elasticity laws are no longer valid, earthquakes cluster, cumulative number of earthquakes departs from the model. State variable extrema provide four reference times that may be used to assess the mechanical state and dynamics of the volcanic edifice. We also performed the spatial modelling of the progressive damage and strain localization around a pressurized magma reservoir. We used Kachanov's damage law and finite element modelling of an initially elastic volcanic edifice pressurized by a spherical magma reservoir, with a constant pressure in the reservoir and various external boundary conditions. At each node of the model, Young's modulus is decreased if deviatoric stress locally reaches the Mohr-Coulomb plastic threshold. For a compressive horizontal stress, the result shows a complex strain localization pattern, showing reverse and normal faulting very similar to what is obtained from analog modelling and observed at volcanic resurgent domes.

Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

NASA Astrophysics Data System (ADS)

Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

2018-04-01

Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase flow generated during explosive particle dispersal indicates that the particle momentum flux is the dominant term in the near field. Both the gas and particle loading must be taken into account when determining the damage to nearby structures following the detonation of a high-explosive charge surrounded by a material layer.

Explosion impacts during transport of hazardous cargo: GIS-based characterization of overpressure impacts and delineation of flammable zones for ammonia.

PubMed

Inanloo, Bahareh; Tansel, Berrin

2015-06-01

The aim of this research was to investigate accidental releases of ammonia followed by an en-route incident in an attempt to further predict the consequences of hazardous cargo accidents. The air dispersion model Areal Locations of Hazardous Atmospheres (ALOHA) was employed to track the probable outcomes of a hazardous material release of a tanker truck under different explosion scenarios. The significance of identification of the flammable zones was taken into consideration; in case the flammable vapor causes an explosion. The impacted areas and the severity of the probable destructions were evaluated for an explosion by considering the overpressure waves. ALOHA in conjunction with ArcGIS was used to delineate the flammable and overpressure impact zones for different scenarios. Based on the results, flammable fumes were formed in oval shapes having a chief axis along the wind direction at the time of release. The expansions of the impact areas under the overpressure value which can lead to property damage for 2 and 20 tons releases, under very stable and unstable atmospheric conditions were estimated to be around 1708, 1206; 3742, 3527 feet, respectively, toward the wind direction. A sensitivity analysis was done to assess the significance of wind speed on the impact zones. The insight provided by this study can be utilized by decision makers in transportation of hazardous materials as a guide for possible rerouting, rescheduling, or limiting the quantity of hazardous cargo to reduce the possible impacts after hazardous cargo accidents during transport. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ares I Scale Model Acoustic Tests Instrumentation for Acoustic and Pressure Measurements

NASA Technical Reports Server (NTRS)

Vargas, Magda B.; Counter, Douglas D.

2011-01-01

The Ares I Scale Model Acoustic Test (ASMAT) was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116. The test article included a 5% scale Ares I vehicle model and tower mounted on the Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments located throughout the test article. There were four primary ASMAT instrument suites: ignition overpressure (IOP), lift-off acoustics (LOA), ground acoustics (GA), and spatial correlation (SC). Each instrumentation suite incorporated different sensor models which were selected based upon measurement requirements. These requirements included the type of measurement, exposure to the environment, instrumentation check-outs and data acquisition. The sensors were attached to the test article using different mounts and brackets dependent upon the location of the sensor. This presentation addresses the observed effect of the sensors and mounts on the acoustic and pressure measurements.

The Fluid Flow Evolution During the Seismic Cycle Within Overpressured Fault Zones

NASA Astrophysics Data System (ADS)

de Paola, Nicola; Vanhunen, Jeroen; Collettini, Cristiano; Faulkner, Dan

2010-05-01

The integration of seismic reflection profiles with well-located earthquakes shows that the mainshocks of the 1997 Umbria-Marche seismic sequence (Mw < 6) nucleated at about 6 km depth, within the Triassic Evaporites, a 2 km thick sequence made of interbedded anhydrites and dolostones. Two boreholes, drilled northwest of the epicentral area, encountered CO2 fluid overpressures at about 0.8 of the lithostatic load, at about 4 km depth. It has been proposed that the time-space evolution of the 1997 aftershock sequence, was driven by the coseismic release of trapped high-pressure fluids (lv = 0.8), within the Triassic Evaporites. In order to understand whether CO2 fluid overpressure can be maintained up to the coseismic period, and trigger earthquake nucleation, we modelled fluid flow through a mature fault zone within the Triassic Evaporites. We assume that fluid flow within the fault zone occurs in accord with the Darcy's Law. Under this condition, a near lithostatic pore pressure gradient can develop, within the fault zone, when the upward transport of fluid along the fault zone exceeds the fluid loss in a horizontal direction. Our model's parameters are: a) Fault zone structure: model inputs have been obtained from large fault zone analogues derived from field observation. The architecture of large fault zones within the TE is given by a distinct fault core, up to few meters thick, of very fine-grained fault rocks (cataclasites and fault gouge), where most of the shear strain has been accommodated, surrounded by a geometrically complex and heterogeneous damage zone (up to few tens of meters wide). The damage zone is characterized by adjacent zones of heavily fractured rocks (dolostones) and foliated rocks displaying little fracturing (anhydrites). b) Fault zone permeability: field data suggests that the permeability of the fault core is relatively low due to the presence of fine grained fault rocks (k < 10E-18 m2). The permeability of the dolostones, within the damage zone, is likely to be high and controlled by mesoscale fracture patterns (k > 10E-17 m2). For the anhydrites, the permeability and porosity development was continuously measured prior and throughout triaxial loading tests, performed on borehole samples. The permeability of the anhydrites within the damage zone, due to the absence of mesoscale fracture patterns within Ca-sulphates layers, has been assumed to be as low as the values measured during our lab experiments (k = 10E-17 - 10E-20 m2). Our model results show that, during the seismic cycle, the lateral fluid flux, across the fault zone, is always lower than the vertical parallel fluid flux. Under these conditions fluid overpressure within the fault zone can be sustained up to the coseismic period when earthquake nucleation occurs. Our modelling shows that during extensional loading, overpressured fault zones within the Triassic Evaporites may develop and act as asperities, i.e. they are mechanically weaker than faults within the overlain carbonates at hydrostatic (lv = 0.4) pore fluid pressure conditions.

Water Deluge Test at Launch Complex 39B

NASA Image and Video Library

2018-05-24

About 450,000 gallons of water flow at high speed from a holding tank through new and modified piping and valves, the flame trench, flame deflector nozzles and mobile launcher interface risers during a wet flow test on May 24, 2018, at Launch Pad 39B at NASA's Kennedy Space Center in Florida. At peak flow, the water reached about 100 feet in the air above the pad surface. The test was performed by Exploration Ground Systems to confirm the performance of the Ignition Overpressure/Sound Suppression system. During launch of NASA's Space Launch System rocket and Orion spacecraft, the high-speed water flow will help protect the vehicle from the extreme acoustic and temperature environment during ignition and liftoff.

Vibration Responses of Test Structure No. 2 During the Edward Air Force Base Phase of the National Sonic Boom Program

NASA Technical Reports Server (NTRS)

Findley, D. S.; Huckel, V.; Hubbard, H. H.

1975-01-01

In order to evaluate reaction of people to sonic booms of varying overpressures and time durations, a series of closely controlled and systematic flight tests/studies were conducted from June 3 to June 23, 1966. The dynamic responses of several building structures were measured, with emphasis on a two-story residence structure. Sample acceleration and strain recordings from F-104, B-58, and XB-70 sonic boom exposures are included, along with tabulations of the maximum acceleration and strain values measured for each one of about 140 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft.

Structural response and gas dynamics of an airship exposed to a nuclear detonation. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilstad, D.A.; Weeber, C.G.; Kviljord, A.

1960-04-25

Four Model ZSG-3 airships, U. S. Navy Bureau of Aeronautics Nos. 40, 46, 77, and 92, participated during Operation Plumbbob to determine the response characteristics of the Model ZSG-3 airship when subjected to a nuclear detonation in order to establish criteria for safe escape distances for airship delivery of antisubmarine warfare special weapons. Restrained response data for 0.40-psi overpressure input were obtained during Shot Franklin with the ZSG-3 No. 77 moored tail to the blast. Unrestrained response data for 0.75-psi overpressure input were obtained during Shot Stokes with the ZSG-3 No. 40 free ballooned, tail to the blast, 300 feetmore » aboveground. The first airship exposed to overpressure experienced a structural failure of the nose cone when it was rammed into the mooring mast, together with a tear of the forward ballonet which necessitated deflation of the envelope. The second airship broke in half and crashed following a circumferential failure of the envelope originating at the bottom of the envelope, forward of the car.« less

Pretest predictions for the response of a 1:8-scale steel LWR containment building model to static overpressurization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clauss, D.B.

The analyses used to predict the behavior of a 1:8-scale model of a steel LWR containment building to static overpressurization are described and results are presented. Finite strain, large displacement, and nonlinear material properties were accounted for using finite element methods. Three-dimensional models were needed to analyze the penetrations, which included operable equipment hatches, personnel lock representations, and a constrained pipe. It was concluded that the scale model would fail due to leakage caused by large deformations of the equipment hatch sleeves. 13 refs., 34 figs., 1 tab.

Environmental Impact Statement, Establishment of the Gandy Range Extension and Adjacent Restricted Airspace as an Area for Supersonic Flight Training, Hill AFB, Utah

DTIC Science & Technology

1985-10-03

years, there have been noise complaintn centering out of the Montello, Nevada and Park Valley, Utah areas, There has been alleged damage to chicken ...of mink to sonic booms does not affect reproduction. 4. All eýxperisental evidence to date indicates that the exposure of chicken eggs to sonic booms...structural response to sonic boom overpressure. The most intens-ive test was conducted at White Sands, New Mexico , where 21 structures of various design

Critique of An Analysis of the Blast Overpressure Study Data Comparing Three Exposure Criteria, by Murphy, Khan, and Shaw

DTIC Science & Technology

2010-08-01

produced a 25 dB or greater threshold shift at any audiometric test frequency. This was referred to as a “full audiometric failure.” In practice ...ear was facing the source, holes in muff at grazing incidence). In practice , rigid control of impulse presentation cannot be achieved in training...First, practical considerations resulted in the AS using groups of 60 Ss who were exposed to higher and higher energies (7 levels, 6, 12, 25, 50, and

Subacute Oxidative Stress and Glial Reactivity in the Amygdala are Associated with Increased Anxiety Following Blast Neurotrauma.

PubMed

Sajja, Venkata Siva Sai Sujith; Hubbard, William B; VandeVord, Pamela J

2015-08-01

Behavioral symptoms, such as anxiety, are widely reported after blast overpressure (BOP) exposure. Amygdalar vulnerability to increasing magnitudes of BOP has not been investigated, and single exposures to blast have been limited to acute (<72 h) assessment. Rats were exposed to a single low, moderate, or high BOP (10, 14, or 24 psi) with an advanced blast simulator to test the susceptibility of the amygdala. Anxiety-like behavior was observed in the low- and moderate-pressure groups when subjected to the light/dark box assessment 7 days after the blast but not in high-pressure group. Immunohistochemistry was performed to measure apoptosis (cleaved caspase-3), neuronal loss (NeuN), reactive astrocytes (glial fibrillary acidic protein), microglia (Iba-1), and oxidative stress (CuZn superoxide dismutase). Slower progression of injury cascades was associated with a significant increase in anxiety, apoptosis, and astrogliosis in the low pressure group compared with others. A significant increase of CuZn superoxide dismutase in the low pressure group could be associated with neuroprotection from cell death caused by oxidative stress because neuronal loss was significant in the moderate- and high- but not the low-pressure group. Overall, this study demonstrated that overpressure as low as 10 psi can induce subacute anxiety, in addition to neuropathologic changes in the amygdala.

Neuronal Injury and Glial Changes Are Hallmarks of Open Field Blast Exposure in Swine Frontal Lobe

PubMed Central

Kallakuri, Srinivasu; Desai, Alok; Feng, Ke; Tummala, Sharvani; Saif, Tal; Chen, Chaoyang; Zhang, Liying; Cavanaugh, John M.; King, Albert I.

2017-01-01

With the rapid increase in the number of blast induced traumatic brain injuries and associated neuropsychological consequences in veterans returning from the operations in Iraq and Afghanistan, the need to better understand the neuropathological sequelae following exposure to an open field blast exposure is still critical. Although a large body of experimental studies have attempted to address these pathological changes using shock tube models of blast injury, studies directed at understanding changes in a gyrencephalic brain exposed to a true open field blast are limited and thus forms the focus of this study. Anesthetized, male Yucatan swine were subjected to forward facing medium blast overpressure (peak side on overpressure 224–332 kPa; n = 7) or high blast overpressure (peak side on overpressure 350–403 kPa; n = 5) by detonating 3.6 kg of composition-4 charge. Sham animals (n = 5) were subjected to all the conditions without blast exposure. After a 3-day survival period, the brain was harvested and sections from the frontal lobes were processed for histological assessment of neuronal injury and glial reactivity changes. Significant neuronal injury in the form of beta amyloid precursor protein immunoreactive zones in the gray and white matter was observed in the frontal lobe sections from both the blast exposure groups. A significant increase in the number of astrocytes and microglia was also observed in the blast exposed sections compared to sham sections. We postulate that the observed acute injury changes may progress to chronic periods after blast and may contribute to short and long-term neuronal degeneration and glial mediated inflammation. PMID:28107370

Pathophysiology of blast-induced ocular trauma in rats after repeated exposure to low-level blast overpressure.

PubMed

Choi, Jae Hyek; Greene, Whitney A; Johnson, Anthony J; Chavko, Mikulas; Cleland, Jeffery M; McCarron, Richard M; Wang, Heuy-Ching

2015-04-01

The incidence of blast-induced ocular injury has dramatically increased due to advances in weaponry and military tactics. A single exposure to blast overpressure (BOP) has been shown to cause damage to the eye in animal models; however, on the battlefield, military personnel are exposed to BOP multiple times. The effects of repeated exposures to BOP on ocular tissues have not been investigated. The purpose of this study is to characterize the effects of single or repeated exposure on ocular tissues. A compressed air shock tube was used to deliver 70 ± 7 KPa BOP to rats, once (single blast overpressure [SBOP]) or once daily for 5 days (repeated blast overpressure [RBOP]). Immunohistochemistry was performed to characterize the pathophysiology of ocular injuries induced by SBOP and RBOP. Apoptosis was determined by quantification activated caspase 3. Gliosis was examined by detection of glial fibrillary acidic protein (GFAP). Inflammation was examined by detection of CD68. Activated caspase 3 was detected in ocular tissues from all animals subjected to BOP, while those exposed to RBOP had more activated caspase 3 in the optic nerve than those exposed to SBOP. GFAP was detected in the retinas from all animals subjected to BOP. CD68 was detected in optic nerves from all animals exposed to BOP. SBOP and RBOP induced retinal damage. RBOP caused more apoptosis in the optic nerve than SBOP, suggesting that RBOP causes more severe optic neuropathy than SBOP. SBOP and RBOP caused gliosis in the retina and increased inflammation in the optic nerve. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

DOEpatents

Albin, David S.; Carapella, Jeffrey J.; Tuttle, John R.; Contreras, Miguel A.; Gabor, Andrew M.; Noufi, Rommel; Tennant, Andrew L.

1995-07-25

A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

Blast shock wave mitigation using the hydraulic energy redirection and release technology.

PubMed

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-01-01

A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel.

Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology

PubMed Central

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-01-01

A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel. PMID:22745740

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

PubMed

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

2004-04-01

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

Acoustic investigation of the aperture dynamics of an elastic membrane closing an overpressurized cylindrical cavity

NASA Astrophysics Data System (ADS)

Sánchez, Claudia; Vidal, Valérie; Melo, Francisco

2015-08-01

We report an experimental study of the acoustic signal produced by the rupture of an elastic membrane that initially closes a cylindrical overpressurized cavity. This configuration has been recently used as an experimental model system for the investigation of the acoustic emission from the bursting of elongated gas bubbles rising in a conduit. Here, we investigate the effect of the membrane rupture dynamics on the acoustic signal produced by the pressure release by changing the initial tension of the membrane. The initial overpressure in the cavity is fixed at a value such that the system remains in the linear acoustic regime. For large initial membrane deformation, the rupture time τ rup is small compared to the wave propagation time in the cavity and the pressure wave inside the conduit can be fully captured by the linear theory. For low membrane tension, a hole is pierced in the membrane but its rupture does not occur. For intermediate deformation, finally, the rupture progresses in two steps: first the membrane opens slowly; then, after reaching a critical size, the rupture accelerates. A transversal wave is excited along the membrane surface. The characteristic signature of each opening dynamics on the acoustic emission is described.

Petroleum hydrogeology of the Great Hungarian Plain, Eastern Pannonian Basin, Hungary

NASA Astrophysics Data System (ADS)

Almasi, Istvan

The results of a regional scale hydrogeological investigation conducted in the Great Hungarian Plain, Eastern Pannonian Basin, for the purposes of petroleum exploration are presented. Two regional aquitards and three regional aquifers were determined in the poorly-to-well consolidated clastic basin fill of the Neogene-Quaternary age and the indurated basement of the Pre-Neogene age. The fluid-potential field was mapped using measured values of stabilised water level and pore-pressure. Two regional fluid flow regimes were recognised: an upper gravity-driven flow regime, and a lower overpressured regime, where super-hydrostatic pore pressures of 1--35 MPa are encountered. The transition between the two flow regimes does not correlate with any particular hydrostratigraphic boundary or elevation range. Apparently, its position and nature are controlled by the morphology of the rigid basement, and locally by the permeability contrasts within the overlying hydrostratigraphic units. Local hydrostratigraphic breaches and conduit faults facilitate hydraulic communication across the regional aquitards. The basin is hydraulically continuous. The mapped groundwater flow directions do not match the predictions of compactional flow models. At two gas-fields, up to 10 MPa overpressures are probably caused by buoyancy forces. Transient overpressures can not be maintained over geologic time in the basin, due to the rock's low hydraulic resistance. Regional tectonic compressive stress, probably with a Recent increase in intensity, offers a new and plausible explanation for the distribution pattern of overpressures in the Great Hungarian Plain. Gravity-driven groundwater flow plays a determinant role in petroleum migration and entrapment. Compactional flow models can explain the present-day position of several known petroleum accumulations within the overpressured regime. However, most accumulations are also associated with particular fluid-potential anomaly-patterns of the actual flow field, which also suggest the possibility of petroleum remigration toward the graben centres and upward. The geothermal characteristics show that pure conduction is the dominant regional heat transfer mechanism within the entire basin. The encountered advective thermal anomalies correlate well with fluid potential anomalies observed in both fluid flow regimes, as well as with certain petroleum accumulations. Toth's (1980) hydraulic theory of petroleum migration was found applicable in a deforming Neogene sedimentary basin, the Great Hungarian Plain.* *This dissertation includes a CD that is compound (contains both a paper copy and a CD as part of the dissertation). The CD requires the following applications: Adobe Acrobat, Microsoft Office.

Multiscale pore networks and their effect on deformation and transport property alteration associated with hydraulic fracturing

NASA Astrophysics Data System (ADS)

Daigle, Hugh; Hayman, Nicholas; Jiang, Han; Tian, Xiao; Jiang, Chunbi

2017-04-01

Multiple lines of evidence indicate that, during a hydraulic fracture stimulation, the permeability of the unfractured matrix far from the main, induced tensile fracture increases by one to two orders of magnitude. This permeability enhancement is associated with pervasive shear failure in a large region surrounding the main induced fracture. We have performed low-pressure gas sorption, mercury intrusion, and nuclear magnetic resonance measurements along with high-resolution scanning electron microscope imaging on several preserved and unpreserved shale samples from North American basins before and after inducing failure in confined compressive strength tests. We have observed that the pore structure in intact samples exhibits multiscale behavior, with sub-micron-scale pores in organic matter connected in isolated, micron-scale clusters which themselves are connected to each other through a network of microcracks. The organic-hosted pore networks are poorly connected due to a significant number of dead-end pores within the organic matter. Following shear failure, we often observe an increase in pore volume in the sub-micron range, which appears to be related to the formation of microcracks that propagate along grain boundaries and other planes of mechanical strength contrast. This is consistent with other experimental and field evidence. In some cases these microcracks cross or terminate in organic matter, intersecting the organic-hosted pores. The induced microcrack networks typically have low connectivity and do not appreciably increase the connectivity of the overall pore network. However, in other cases the shear deformation results in an overall pore volume decrease; samples which exhibit this behavior tend to have more clay minerals. Our interpretation of these phenomena is as follows. As organic matter is converted to hydrocarbons, organic-hosted pores develop, and the hydrocarbons contained in these pores are overpressured. The disconnected nature of these clusters of organic-hosted pores prevents the overpressure from dissipating, resulting in localized overpressure at the micron scale. When the rock is subjected to a hydraulic fracture stimulation, the rock surrounding the main induced fracture experiences shear deformation. Those parts of the rock that contain overpressured fluids in the organic-hosted pores will be more likely to experience dilatancy in the form of brittle deformation; the portions of the rock lacking in organic-hosted pores will tend to experience compactive shear failure since the effective normal stresses are larger. The microcrack networks that propagate into the regions of organic-hosted porosity allow the hydrocarbons resident in those pores to migrate to the main induced tensile fractures. The disconnected nature of the microcrack networks causes only a slight increase in permeability, which is consistent with other observations. Our work illustrates how multiscale pore networks in shale interact with in situ stresses to affect the bulk shale rheology.

Characteristics of Mare Deposits on the Eastern Limb of the Moon: Implications for Magma Transport Mechanisms

NASA Astrophysics Data System (ADS)

Yingst, R. A.; Head, J. W.

1996-03-01

Lunar volcanic history has been examined in light of geomorphological and stratigraphic constraints placed upon the surface features. Compositional and petrological analyses have provided models for the conditions of mare parent magma generation . The connection between lunar magma source regions and volcanic surface features remains unclear, however, both conceptually and quantitatively with respect to our understanding of transport mechanisms. It has been suggested that mare emplacement was controlled by propagation of dikes driven by the overpressurization of diapir-like source regions stalled below the cooling lunar highland crust. Recent analyses of the characteristics of lava ponds in the South Pole/Aitken and Orientale/Mendel-Rydberg basins based on Clementine, Lunar Orbiter and Zond data have provided evidence that supports this theory. In this contribution we report on an analysis of the areas, volumes, modes of occurrence and crustal thicknesses for mare deposits in the Marginis and Smythii basins, and investigate implications for magma transport mechanisms.

Origin, mode of emplacement, and trace element geochemistry of albertite at the type locality, Albert Mines, southeastern New Brunswick, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrell, K.P.J.; Mossman, D.J.

1995-07-01

Fracturing of oil shale was coeval with albertite vein formation at Albert Mines early in the diagenetic history of the Lower Carboniferous (Tourmasian) Albert Formation. Albertite of this type locality is a pre-oil bitumen produced as a result of overpressuring due to a high rate of hydrocarbon generation and, as such, is largely preserved in an immature source rock. Dolomite precipitated in albertite during emplacement of the latter, and was sourced from an accompanying CO{sub 2}-rich fluid phase. Trace element contents of albertite are within the range of selected other major bitumen occurrences and, except for nickel, are lower thanmore » those of the host rock. Ratios of Ni/V are elevated in comparison with the host oil shale and with other bitumen occurrences. Carbon isotope values for albertite range from 27.92 to 30.80 {per_thousand}, {delta} {sup 13}C, within the range of most conventional crudes.« less

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Vibration responses of test structure no. 1 during the Edwards Air Force Base phase of the national sonic boom program. [F-104, B-58, and XB-70 sonic boom exposures

NASA Technical Reports Server (NTRS)

Findley, D. S.; Huckel, V.; Henderson, H. R.

1975-01-01

In order to evaluate reaction of people to sonic booms of varying overpressures and time durations, a series of closely controlled and systematic flight test studies were conducted in the vicinity of Edwards AFB, California, from June 3 to June 23, 1966. The dynamic responses of several building structures were measured as a part of these studies, and the measurements made in a one-story residence structure (Edwards test structure No. 1) are presented. Sample acceleration and strain recordings are presented from F-104, B-58, and XB-70 sonic-boom exposures, along with tabulations of the maximum acceleration and strain values measured for each one of about 140 flight tests. These data are compared with similar measurements for engine noise exposures of the building during simulated landing approaches and takeoffs of KC-135 aircraft.

LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidester, S K; Vandersall, K S; Switzer, L L

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04more » has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.« less

A loudness calculation procedure applied to shaped sonic booms

NASA Technical Reports Server (NTRS)

Shepherd, Kevin P.; Sullivan, Brenda M.

1991-01-01

Described here is a procedure that can be used to calculate the loudness of sonic booms. The procedure is applied to a wide range of sonic booms, both classical N-waves and a variety of other shapes of booms. The loudness of N-waves is controlled by overpressure and the associated rise time. The loudness of shaped booms is highly dependent on the characteristics of the initial shock. A comparison of the calculated loudness values indicates that shaped booms may have significantly reduced loudness relative to N-waves having the same peak overpressure. This result implies that a supersonic transport designed to yield minimized sonic booms may be substantially more acceptable than an unconstrained design.

Prevention of Over-Pressurization During Combustion in a Sealed Chamber

NASA Technical Reports Server (NTRS)

Gokoglu, Suleyman A.; Niehaus, Justin E.; Olson, Sandra L.; Dietrich, Daniel L.; Ruff, Gary A.; Johnston, Michael C.

2012-01-01

The combustion of flammable material in a sealed chamber invariably leads to an initial pressure rise in the volume. The pressure rise is due to the increase in the total number of gaseous moles (condensed fuel plus chamber oxygen combining to form gaseous carbon dioxide and water vapor) and, most importantly, the temperature rise of the gas in the chamber. Though the rise in temperature and pressure would reduce with time after flame extinguishment due to the absorption of heat by the walls and contents of the sealed spacecraft, the initial pressure rise from a fire, if large enough, could lead to a vehicle over-pressure and the release of gas through the pressure relief valve. This paper presents a simple lumped-parameter model of the pressure rise in a sealed chamber resulting from the heat release during combustion. The transient model considers the increase in gaseous moles due to combustion, and heat transfer to the chamber walls by convection and radiation and to the fuel-sample holder by conduction, as a function of the burning rate of the material. The results of the model are compared to the pressure rise in an experimental chamber during flame spread tests as well as to the pressure falloff after flame extinguishment. The experiments involve flame spread over thin solid fuel samples. Estimates of the heat release rate profiles for input to the model come from the assumed stoichiometric burning of the fuel along with the observed flame spread behavior. The sensitivity of the model to predict maximum chamber pressure is determined with respect to the uncertainties in input parameters. Model predictions are also presented for the pressure profile anticipated in the Fire Safety-1 experiment, a material flammability and fire safety experiment proposed for the European Space Agency (ESA) Automated Transfer Vehicle (ATV). Computations are done for a range of scenarios including various initial pressures and sample sizes. Based on these results, various mitigation approaches are suggested to prevent vehicle over-pressurization and help guide the definition of the space experiment.

Volcano Deformation and Eruption Forecasting using Data Assimilation: Building the Strategy

NASA Astrophysics Data System (ADS)

Bato, M. G.; Pinel, V.; Yan, Y.

2016-12-01

In monitoring active volcanoes, the magma overpressure is one of the key parameters used in forecasting volcanic eruptions. This can be inferred from the ground displacements measured on the Earth's surface by applying inversion techniques. However, during the inversion, we lose the temporal characteristic along with huge amount of information about the behaviour of the volcano. Our work focuses on developing a strategy in order to better forecast the magma overpressure using data assimilation. Data assimilation is a sequential time-forward process that best combines models and observations, sometimes a priori information based on error statistics, to predict the state of a dynamical system. It has gained popularity in various fields of geoscience (e.g. ocean-weather forecasting, geomagnetism and natural resources exploration), but remains a new and emerging technique in the field of volcanology. With the increasing amount of geodetic data (i.e. InSAR and GPS) recorded on volcanoes nowadays, and the wide-range availability of dynamical models that can provide better understanding about the volcano plumbing system; developing a forecasting framework that can efficiently combine them is crucial. Here, we particularly built our strategy on the basis of the Ensemble Kalman Filter (EnKF) [1]. We predict the temporal behaviours of the magma overpressures and surface deformations by adopting the two-magma chamber model proposed by Reverso et. al., 2014 [2] and by using synthetic GPS and/or InSAR data. Several tests are performed in order to answer the following: 1) know the efficiency of EnKF in forecasting volcanic unrests, 2) constrain unknown parameters of the model, 3) properly use GPS and/or InSAR during assimilation and 4) compare EnKF with classic inversion while using the same dynamical model. Results show that EnKF works well with the synthetic cases and there is a great potential in utilising the method for real-time monitoring of volcanic unrests. [1] Evensen, G., The Ensemble Kalman Filter: theoretical formulation and practical implementation. Ocean Dyn.,53, 343-367, 2003 [2] T. Reverso, J. Vandemeulebrouck, F. Jouanne, V. Pinel, T. Villemin, E. Sturkell, A two-magma chamber as a source of deformation at Grimsvötn volcano, Iceland, JGR, 2014

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vandersall, K S; Switzer, L L; Garcia, F

2005-09-26

Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This workmore » will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.« less

Posttest destructive examination of the steel liner in a 1:6-scale reactor containment model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, L.D.

A 1:6-scale model of a nuclear reactor containment model was built and tested at Sandia National Laboratories as part of research program sponsored by the Nuclear Regulatory Commission to investigate containment overpressure test was terminated due to leakage from a large tear in the steel liner. A limited destructive examination of the liner and anchorage system was conducted to gain information about the failure mechanism and is described. Sections of liner were removed in areas where liner distress was evident or where large strains were indicated by instrumentation during the test. The condition of the liner, anchorage system, and concretemore » for each of the regions that were investigated are described. The probable cause of the observed posttest condition of the liner is discussed.« less

Thermal explosion analysis of methyl ethyl ketone peroxide by non-isothermal and isothermal calorimetric applications.

PubMed

Chi, Jen-Hao; Wu, Sheng-Hung; Shu, Chi-Min

2009-11-15

In the past, process incidents attributed to organic peroxides (OPs) that involved near misses, over-pressures, runaway reactions, and thermal explosions occurred because of poor training, human error, incorrect kinetic assumptions, insufficient change management, and inadequate chemical knowledge in the manufacturing process. Calorimetric applications were employed broadly to test organic peroxides on a small-scale because of their thermal hazards, such as exothermic behavior and self-accelerating decomposition in the laboratory. In essence, methyl ethyl ketone peroxide (MEKPO) is highly reactive and exothermically unstable. In recent years, it has undergone many thermal explosions and runaway reaction incidents in the manufacturing process. Differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and thermal activity monitor (TAM) were employed to analyze thermokinetic parameters and safety index. The intent of the analyses was to facilitate the use of various auto-alarm equipments to detect over-pressure, over-temperature, and hazardous materials leaks for a wide spectrum of operations. Results indicated that MEKPO decomposition is detected at low temperatures (30-40 degrees C), and the rate of decomposition was shown to exponentially increase with temperature and pressure. Determining time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), maximum temperature (T(max)), exothermic onset temperature (T(0)), and heat of decomposition (DeltaH(d)) was essential for identifying early-stage runaway reactions effectively for industries.

Explosion hazards of LPG-air mixtures in vented enclosure with obstacles.

PubMed

Zhang, Qi; Wang, Yaxing; Lian, Zhen

2017-07-15

Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent. Dynamic pressures produced by an indoor LPG explosion reach their maximum always beyond the vent no matter obstacles are present or not in the enclosure. A LPG explosion in a vented enclosure with built-in obstacles is strong enough to make the brick and mortar wall with a thickness of 370mm damaged. If there is no obstacle in the enclosure, the lower explosion pressure of several kPa can not break the brick and mortar wall with a thickness of 370mm. For a LPG explosion produced in an enclosure with a vent, main hazards, within the vent, are overpressure and high temperature. However main hazards are dynamic pressure, blast wind, and high temperature beyond the vent. Copyright © 2017 Elsevier B.V. All rights reserved.

The relative effects of cavitation and nonlinear ultrasound propagation on HIFU lesion dynamics in a tissue phantom

NASA Astrophysics Data System (ADS)

Khokhlova, Vera A.; Bailey, Michael R.; Reed, Justin; Kaczkowski, Peter J.

2004-05-01

The relative importance of the effects of acoustic nonlinearity and cavitation in HIFU lesion production is studied experimentally and theoretically in a polyacrylamide gel. A 2-MHz transducer of 40-mm diameter and 45-mm focal length was operated at different regimes of power, and in cw or duty-cycle regimes with equal mean intensity. Elevated static pressure was applied to suppress bubbles, increase boiling temperature, and thus to isolate the effect of acoustic nonlinearity in the enhancement of lesion production. Experimental data were compared with the results of simulations performed using a KZK acoustic model combined with the bioheat equation and thermal dose formulation. Boiling and the typical tadpole-shaped lesion shifting towards the transducer were observed under standard atmospheric pressure. No boiling was detected and a symmetric thermal lesion formed in the case of overpressure. A delay in lesion inception time was registered with overpressure, which was hypothesized to be due to suppressed microbubble dynamics. The effect of acoustic nonlinearity was revealed as a substantial decrease in the lesion inception time and an increase in the lesion size for high-amplitude waves under both standard and overpressure conditions. [Work supported by ONRIFO, NASA/NSBRI, NIH Fogarty, and CRDF grants.

Statistics of peak overpressure and shock steepness for linear and nonlinear N-wave propagation in a kinematic turbulence.

PubMed

Yuldashev, Petr V; Ollivier, Sébastien; Karzova, Maria M; Khokhlova, Vera A; Blanc-Benon, Philippe

2017-12-01

Linear and nonlinear propagation of high amplitude acoustic pulses through a turbulent layer in air is investigated using a two-dimensional KZK-type (Khokhlov-Zabolotskaya-Kuznetsov) equation. Initial waves are symmetrical N-waves with shock fronts of finite width. A modified von Kármán spectrum model is used to generate random wind velocity fluctuations associated with the turbulence. Physical parameters in simulations correspond to previous laboratory scale experiments where N-waves with 1.4 cm wavelength propagated through a turbulence layer with the outer scale of about 16 cm. Mean value and standard deviation of peak overpressure and shock steepness, as well as cumulative probabilities to observe amplified peak overpressure and shock steepness, are analyzed. Nonlinear propagation effects are shown to enhance pressure level in random foci for moderate initial amplitudes of N-waves thus increasing the probability to observe highly peaked waveforms. Saturation of the pressure level is observed for stronger nonlinear effects. It is shown that in the linear propagation regime, the turbulence mainly leads to the smearing of shock fronts, thus decreasing the probability to observe high values of steepness, whereas nonlinear effects dramatically increase the probability to observe steep shocks.

Optimal control of fuel overpressure in a polymer electrolyte membrane fuel cell with hydrogen transfer leak during load change

NASA Astrophysics Data System (ADS)

Ebadighajari, Alireza; DeVaal, Jake; Golnaraghi, Farid

2017-02-01

Formation of membrane pinholes is a common defect in fuel cells, inflicting more cost and making less durable cells. This work focuses on mitigating this issue, and offers a continuous online treatment instead of attempting to dynamically model the hydrogen transfer leak rate. This is achieved by controlling the differential pressure between the anode and cathode compartments at the inlet side of the fuel cell stack, known as the fuel overpressure. The model predictive control approach is used to attain the objectives in a Ballard 9-cell Mk1100 polymer electrolyte membrane fuel cell (PEMFC) with inclusion of hydrogen transfer leak. Furthermore, the pneumatic modeling technique is used to model the entire anode side of a fuel cell station. The hydrogen transfer leak is embedded in the model in a novel way, and is considered as a disturbance during the controller design. Experimental results for different sizes of hydrogen transfer leaks are provided to show the benefits of fuel overpressure control system in alleviating the effects of membrane pinholes, which in turn increases membrane longevity, and reduces hydrogen emissions in the eventual presence of transfer leaks. Moreover, the model predictive controller provides an optimal control input while satisfying the problem constraints.

Large Steel Tank Fails and Rockets to Height of 30 meters - Rupture Disc Installed Incorrectly.

PubMed

Hedlund, Frank H; Selig, Robert S; Kragh, Eva K

2016-06-01

At a brewery, the base plate-to-shell weld seam of a 90-m(3) vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

Influence of overpressure on formation velocity evaluation of Neogene strata from the eastern Bengal Basin, Bangladesh

NASA Astrophysics Data System (ADS)

Zahid, Khandaker M.; Uddin, Ashraf

2005-06-01

Interpretation of sonic log data of anticlinal structures from eastern Bangladesh reveals significant variations of acoustic velocity of subsurface strata. The amount of variation in velocity is 32% from Miocene to Pliocene stratigraphic units in Titas and Bakhrabad structure, whereas 21% in Rashidpur structure. Velocity fluctuations are influenced by the presence of gas-bearing horizons, with velocities of gas-producing strata 3-7% lower than laterally equivalent strata at similar depth. Average velocities of Miocene Boka Bil and Bhuban formations are, respectively, 2630 and 3480 m/s at Titas structure; 2820 and 3750 m/s at Bakhrabad; and 3430 and 3843 m/s at the Rashidpur structure. From the overall velocity-depth distribution for a common depth range of 915-3000 m, the Titas, Bakhrabad and Rashidpur structures show a gradual increase in velocity with depth. In contrast, the Sitakund anticline in SE Bangladesh reveals a decrease in velocity with depth from 3000 to 4000 m, probably due to the presence of overpressured mudrocks of the Bhuban Formation. Tectonic compression, associated with the Indo-Burmese plate convergence likely contributed the most toward formation of subsurface overpressure in the Sitakund structure situated in the Chittagong-Tripura Fold Belt of the eastern Bengal basin, Bangladesh.

Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

NASA Astrophysics Data System (ADS)

Ren, Shaoran; Liu, Yanmin; Gong, Zhiwu; Yuan, Yujie; Yu, Lu; Wang, Yanyong; Xu, Yan; Deng, Junyu

2018-02-01

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow (SWF) formations during deepwater drilling. We define `sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed (penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

The impact of flow focusing on gas hydrate accumulations in overpressured marine sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nole, Michael; Daigle, Hugh; Cook, Ann

This study demonstrates the potential for flow focusing due to overpressuring in marine sedimentary environments to act as a significant methane transport mechanism from which methane hydrate can precipitate in large quantities in dipping sandstone bodies. Traditionally, gas hydrate accumulations in nature are discussed as resulting from either short-range diffusive methane migration or from long-range advective fluid transport sourced from depth. However, 3D simulations performed in this study demonstrate that a third migration mechanism, short-range advective transport, can provide a significant methane source that is unencumbered by limitations of the other two end-member mechanisms. Short-range advective sourcing is advantageous overmore » diffusion because it can convey greater amounts of methane to sands over shorter timespans, yet it is not necessarily limited by down-dip pore blocking in sands as is typical of updip advection from a deep source. These results are novel because they integrate pore size impacts on spatial solubility gradients, grid block properties that evolve through time, and methane sourcing through microbial methanogenesis into a holistic characterization of environments exposed to multiple methane hydrate sourcing mechanisms. We show that flow focusing toward sand bodies transports large quantities of methane, the magnitude of which are determined by the sand-clay solubility contrast, and generates larger quantities of hydrate in sands than a solely diffusive system; after depositing methane as hydrate, fluid exiting a sand body is depleted in methane and leaves a hydrate free region in its wake above the sand. Additionally, we demonstrate that in overpressured environments, hydrate growth is initially diffusively dominated before transitioning to an advection-dominated regime. The timescale and depth at which this transition takes place depends primarily on the rate of microbial metabolism and the sedimentation rate but only depends loosely on the degree of overpressuring.« less

Mechanical Damage of Tympanic Membrane in Relation to Impulse Pressure Waveform – A Study in Chinchillas

PubMed Central

Gan, Rong Z.; Nakmali, Don; Ji, Xiao D.; Leckness, Kegan; Yokell, Zachary

2016-01-01

Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded with a stainless steel cup covering the animal head. Auditory brainstem response (ABR) and wideband tympanometry were measured before and after exposure to check the hearing threshold and middle ear function. Results show that waveforms recorded in the shielded case were different from those in the open field and the TM rupture threshold in the shielded case was lower than that in the open field (3.4±0.7 vs. 9.1±1.7 psi or 181±1.6 vs. 190±1.9 dB SPL). The impulse pressure energy spectra analysis of waveforms demonstrates that the shielded waveforms include greater energy at high frequencies than that of the open field waves. Finally, a 3D finite element (FE) model of the chinchilla ear was used to compute the distributions of stress in the TM and the TM displacement with impulse pressure waves. The FE model-derived change of stress in response to pressure loading in the shielded case was substantially faster than that in the open case. This finding provides the biomechanical mechanisms for blast induced TM damage in relation to overpressure waveforms. The TM rupture threshold difference between the open and shielded cases suggests that an acoustic role of helmets may exist, intensifying ear injury during blast exposure. PMID:26807796

Wireless system for explosion detection in underground structures

NASA Astrophysics Data System (ADS)

Chikhradze, M.; Bochorishvili, N.; Akhvlediani, I.; Kukhalashvili, D.; Kalichava, I.; Mataradze, E.

2009-06-01

Considering the growing threat of terrorist or accidental explosions in underground stations, underground highway and railway sections improvement of system for protecting people from explosions appears urgent. Current automatic protective devices with blast identification module and blast damping absorbers of various designs as their basic elements cannot be considered effective. Analysis revealed that low reliability of blast detection and delayed generation of start signal for the activation of an absorber are the major disadvantages of protective devices. Besides the transmission of trigger signal to an energy absorber through cable communication reduces the reliability of the operation of protective device due to a possible damage of electric wiring under blast or mechanical attack. This paper presents the outcomes of the studies conducted to select accurate criteria for blast identification and to design wireless system of activation of defensive device. The results of testing of blast detection methods (seismic, EMP, optical, on overpressure) showed that the proposed method, which implies constant monitoring of overpressure in terms of its reliability and response speed, best meets the requirements. Proposed wireless system for explosions identification and activation of protective device consists of transmitter and receiver modules. Transmitter module contains sensor and microprocessor equipped with blast identification software. Receiver module produces activation signal for operation of absorber. Tests were performed in the underground experimental base of Mining Institute. The time between the moment of receiving signal by the sensor and activation of absorber - 640 microsecond; distance between transmitter and receiver in direct tunnel - at least 150m; in tunnel with 900 bending - 50m. This research is sponsored by NATO's Public Diplomacy Division in the framework of "Science for Peace".

Regional pore-fluid pressures in the active western Taiwan thrust belt: A test of the classic Hubbert-Rubey fault-weakening hypothesis

NASA Astrophysics Data System (ADS)

Yue, Li-Fan; Suppe, John

2014-12-01

We document regional pore-fluid pressures in the active Taiwan thrust belt using 55 deep boreholes to test the classic Hubbert-Rubey hypothesis that high static fluid pressures (depth normalized as λ = Pf/ρrgz) account for the extreme weakness of thrust faults, since effective friction μf∗ =μf(1 - λ) . Taiwan fluid pressures are dominated by disequilibrium compaction, showing fully compacted sediments with hydrostatic fluid pressures at shallow depths until the fluid-retention depth zFRD ≈ 3 km, below which sediments are increasingly undercompacted and overpressured. The Hubbert-Rubey fault weakening coefficient is a simple function of depth (1 - λ) ≈ 0.6zFRD/z. We map present-day and pre-erosion fluid pressures and weakening (1 - λ) regionally and show that active thrusts are too shallow relative to zFRD for the classic Hubbert-Rubey mechanism to be important, which requires z ≥ ˜4zFRD ≈ 12 km to have the required order-of-magnitude Hubbert-Rubey fault weakening of (1 - λ) ≤ ˜0.15. The best-characterized thrust is the Chelungpu fault that slipped in the 1999 (Mw = 7.6) Chi-Chi earthquake, which has a low effective friction μf∗ ≈ 0.08- 0.12 , yet lies near the base of the hydrostatic zone at depths of 1-5 km with a modest Hubbert-Rubey weakening of (1 - λ) ≈ 0.4-0.6. Overpressured Miocene and Oligocene detachments at 5-7 km depth have (1 - λ) ≈ 0.3. Therefore, other mechanisms of fault weakening are required, such as the dynamical mechanisms documented for the Chi-Chi earthquake.

Thermodynamic Simulation of Carbonate Cements-Water-Carbon Dioxide Equilibrium in Sandstone for Prediction of Precipitation/Dissolution of Carbonate Cements

PubMed Central

Zhong, Xinyan; Shang, Ruishu; Huang, Lihong

2016-01-01

Carbonate cements, such as calcite, dolomite, ferrocalcite and ankerite, play important roles in the formation of pores in sandstones: precipitation of carbonate cements modifies pores and inhibits compaction, while dissolution creates secondary pores. This work proposed a precipitation-dissolution model for carbonate cements-CO2-H2O system by means of ion equilibrium concentration ([M2+], M = Ca, Mg, Fe or Mn) with different factors, such as temperature, depth, pH, PCO2, variable rock composition and overpressure. Precipitation-dissolution reaction routes were also analyzed by minimization of the total Gibbs free energy (ΔG). Δ[M2+], the variation of [Ca2+], [Fe2+], [Mg2+] or [Mn2+] for every 100 m of burial depths, is used to predict precipitation or dissolution. The calculation results indicate that the increasing temperature results in decrease of equilibrium constant of reactions, while the increasing pressure results in a relatively smaller increase of equilibrium constant; As a result, with increasing burial depth, which brings about increase of both temperature and pressure, carbonate cements dissolve firstly and produces the maximal dissolved amounts, and then precipitation happens with further increasing depth; For example, calcite is dissolving from 0.0 km to 3.0 km with a maximal value of [Ca2+] at depth of 0.8 km, and then precipitates with depth deeper than 3.0 km. Meanwhile, with an increasing CO2 mole fraction in the gaseous phase from 0.1% to 10.0% in carbonate systems, the aqueous concentration of metal ions increases, e.g., dissolved amount of CaFe0.7Mg0.3(CO3)2 increases and reaches maximum of 1.78 mmol·L-1 and 8.26 mmol·L-1 at burial depth of 0.7 km with CO2 mole fraction of 0.1% and 10.0%, respectively. For the influence of overpressure in the calcite system, with overpressure ranging from 36 MPa to 83 MPa, pH reaches a minimum of 6.8 at overpressure of 51 MPa; meanwhile, Δ[Ca2+] increases slightly from -2.24 mmol·L-1 to -2.17 mmol·L-1 and remains negative, indicating it is also a precipitation process at burial depth of 3.9 km where overpressure generated. The method used in this study can be applied in assessing burial precipitation-dissolution processes and predicting possible pores in reservoirs with carbonate cement-water-carbon dioxide. PMID:27907043

Thermodynamic Simulation of Carbonate Cements-Water-Carbon Dioxide Equilibrium in Sandstone for Prediction of Precipitation/Dissolution of Carbonate Cements.

PubMed

Duan, Yiping; Feng, Mingshi; Zhong, Xinyan; Shang, Ruishu; Huang, Lihong

2016-01-01

Carbonate cements, such as calcite, dolomite, ferrocalcite and ankerite, play important roles in the formation of pores in sandstones: precipitation of carbonate cements modifies pores and inhibits compaction, while dissolution creates secondary pores. This work proposed a precipitation-dissolution model for carbonate cements-CO2-H2O system by means of ion equilibrium concentration ([M2+], M = Ca, Mg, Fe or Mn) with different factors, such as temperature, depth, pH, [Formula: see text], variable rock composition and overpressure. Precipitation-dissolution reaction routes were also analyzed by minimization of the total Gibbs free energy (ΔG). Δ[M2+], the variation of [Ca2+], [Fe2+], [Mg2+] or [Mn2+] for every 100 m of burial depths, is used to predict precipitation or dissolution. The calculation results indicate that the increasing temperature results in decrease of equilibrium constant of reactions, while the increasing pressure results in a relatively smaller increase of equilibrium constant; As a result, with increasing burial depth, which brings about increase of both temperature and pressure, carbonate cements dissolve firstly and produces the maximal dissolved amounts, and then precipitation happens with further increasing depth; For example, calcite is dissolving from 0.0 km to 3.0 km with a maximal value of [Ca2+] at depth of 0.8 km, and then precipitates with depth deeper than 3.0 km. Meanwhile, with an increasing CO2 mole fraction in the gaseous phase from 0.1% to 10.0% in carbonate systems, the aqueous concentration of metal ions increases, e.g., dissolved amount of CaFe0.7Mg0.3(CO3)2 increases and reaches maximum of 1.78 mmol·L-1 and 8.26 mmol·L-1 at burial depth of 0.7 km with CO2 mole fraction of 0.1% and 10.0%, respectively. For the influence of overpressure in the calcite system, with overpressure ranging from 36 MPa to 83 MPa, pH reaches a minimum of 6.8 at overpressure of 51 MPa; meanwhile, Δ[Ca2+] increases slightly from -2.24 mmol·L-1 to -2.17 mmol·L-1 and remains negative, indicating it is also a precipitation process at burial depth of 3.9 km where overpressure generated. The method used in this study can be applied in assessing burial precipitation-dissolution processes and predicting possible pores in reservoirs with carbonate cement-water-carbon dioxide.

30 CFR 250.1000 - General requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... equipment (including valves, over-pressure protection devices, cathodic protection equipment, and pigging... marine, coastal, or human environment. (2) The Regional Supervisor may also suspend pipeline operations...

30 CFR 250.1000 - General requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... equipment (including valves, over-pressure protection devices, cathodic protection equipment, and pigging... marine, coastal, or human environment. (2) The Regional Supervisor may also suspend pipeline operations...

30 CFR 250.1000 - General requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... equipment (including valves, over-pressure protection devices, cathodic protection equipment, and pigging... marine, coastal, or human environment. (2) The Regional Supervisor may also suspend pipeline operations...

Pressure-Induced Foaming of Metals

NASA Astrophysics Data System (ADS)

García-Moreno, Francisco; Mukherjee, Manas; Jiménez, Catalina; Banhart, John

2015-05-01

Pressure-induced foaming (PIF) of metals is a foaming technique in which blowing agent free compacted metal powders are foamed. The method consists of heating hot-compacted metallic precursors to above their melting temperature under gas overpressure and foaming them by pressure release. This study focuses on PIF of Al99.7 and AlSi7 alloys under both air or Ar and overpressures up to 9 bar. In situ x-ray radioscopy allows us to follow the foaming process and to perform quantitative analyses of expansion, foam morphology, and coalescence rate. Mass spectrometry helps to identify hydrogen as the foaming gas. Adsorbates on the former powder particles are found to be the primary gas source. Various advantages of this new method are identified and discussed.

Offset shock mounted recorder carrier including overpressure gauge protector and balance joint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, D.K.

1990-12-25

This patent describes a recorder carrier adapted to be included within a well tool. The carrier adapted to include at least one recorder, the recorder being movable within the recorder carrier when the carrier includes the recorder, the well tool adapted to be disposed in a borehole containing well annulus fluid, the recorder carrier adapted to receive well fluid from a formation in the borehole. It comprises overpressure protection means for preventing the well fluid from entering the recorder carrier when a pressure of the well fluid is greater than a predetermined amount above a pressure of the well annulusmore » fluid thereby protecting the recorder from the pressure of the well fluid.« less

An improved probit method for assessment of domino effect to chemical process equipment caused by overpressure.

PubMed

Mingguang, Zhang; Juncheng, Jiang

2008-10-30

Overpressure is one important cause of domino effect in accidents of chemical process equipments. Damage probability and relative threshold value are two necessary parameters in QRA of this phenomenon. Some simple models had been proposed based on scarce data or oversimplified assumption. Hence, more data about damage to chemical process equipments were gathered and analyzed, a quantitative relationship between damage probability and damage degrees of equipment was built, and reliable probit models were developed associated to specific category of chemical process equipments. Finally, the improvements of present models were evidenced through comparison with other models in literatures, taking into account such parameters: consistency between models and data, depth of quantitativeness in QRA.

Tracking chamber made of 15-mm mylar drift tubes

NASA Astrophysics Data System (ADS)

Kozhin, A.; Borisov, A.; Bozhko, N.; Fakhrutdinov, R.; Plotnikov, I.

2017-05-01

We are presenting a drift chamber composed from three layers of mylar drift tubes with outer diameter 15 mm. The pipe is made of strip of mylar film 125 micrometers thick covered with aluminium from the both sides. A strip of mylar is wrapped around the mandrel. Pipe is created by ultrasonic welding. A single drift tube is self-supported structure withstanding 350 g wire tension without supports and internal overpressure. About 400 such tubes were assembled. Design, quality control procedures of the drift tubes are described. Seven chambers were glued from these tubes of 560 mm length. Each chamber consists of 3 layers, 16 tubes per layer. Several chambers were tested with cosmic rays. Results of the tests, counting rate plateau and coordinate resolution are presented.

The effect of suppressors and muzzle brakes on shock wave strength

NASA Astrophysics Data System (ADS)

Phan, K. C.; Stollery, J. L.

Experimental simulations of a gun blast were performed in the course of an optimization study of shock-wave suppressor and muzzle-brake geometry. A single-spark schlieren system was used to photograph the shock waves emerging from a 32-mm shock tube. The suppressor systems tested with respect to the overpressure level included a perforated tube enclosed in an expansion chamber, a cup-and-box suppressor, and noise-absorbent materials inside a suppressor; high suppression efficiency was observed for the first two. Recoil simulation tests, performed with plain and pyramidal baffles, disk, and cylinder, show that the blast level is generally higher for a more efective muzzle brake. An optimum distance from the muzzle to the brake is suggested to be in the region of one caliber.

Human Response to Low-Intensity Sonic Booms Heard Indoors and Outdoors

NASA Technical Reports Server (NTRS)

Sullivan, Brenda M.; Klos, Jacob; Buehrle, Ralph D.; McCurdy, David A.; Haering, Edward A., Jr.

2010-01-01

Test subjects seated inside and outside a house were exposed to low-intensity N-wave sonic booms during a 3-week test period in June 2006- The house was instrumented to measure the booms both inside and out. F-18 aircraft were flown to achieve a variety of boom overpressures from approximately .1 to .6 psf During four test days, seventy-seven test subjects heard the booms while seated inside and outside the house. Using the Magnitude Estimation methodology and artificial reference sounds ; the subjects rated the annoyance of the booms. Since the same subjects heard similar booms both inside and outside the house, comparative ratings of indoor and outdoor annoyance were obtained. For a given metric level, indoor subjects gave higher annoyance scores than outdoor subjects. For a given boom; annoyance scores inside were on average the same as those outside. In a post-test questionnaire, the majority of subjects rated the indoor booms as more annoying than the outdoor ones. These results are discussed in this paper.

Experimental verification of low sonic boom configuration

NASA Technical Reports Server (NTRS)

Ferri, A.; Wang, H. H.; Sorensen, H.

1972-01-01

A configuration designed to produce near field signature has been tested at M = 2.71 and the results are analyzed, by taking in account three-dimensional and second order effects. The configuration has an equivalent total area distribution that corresponds to an airplane flying at 60,000 ft. having a weight of 460,000 lbs, and 300 ft. length. A maximum overpressure of 0.95 lb/square foot has been obtained experimentally. The experimental results agree well with the analysis. The investigation indicates that the three-dimensional effects are very important when the measurements in wind tunnels are taken at small distances from the airplane.

Blast wave mitigation by dry aqueous foams

NASA Astrophysics Data System (ADS)

Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

2013-02-01

This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

The quantitative studies on gas explosion suppression by an inert rock dust deposit.

PubMed

Song, Yifan; Zhang, Qi

2018-07-05

The traditional defence against propagating gas explosions is the application of dry rock dust, but not much quantitative study on explosion suppression of rock dust has been made. Based on the theories of fluid dynamics and combustion, a simulated study on the propagation of premixed gas explosion suppressed by deposited inert rock dust layer is carried out. The characteristics of the explosion field (overpressure, temperature, flame speed and combustion rate) at different deposited rock dust amounts are investigated. The flame in the pipeline cannot be extinguished when the deposited rock dust amount is less than 12 kg/m 3 . The effects of suppressing gas explosion become weak when the deposited rock dust amount is greater than 45 kg/m 3 . The overpressure decreases with the increase of the deposited rock dust amounts in the range of 18-36 kg/m 3 and the flame speed and the flame length show the same trends. When the deposited rock dust amount is 36 kg/m 3 , the overpressure can be reduced by 40%, the peak flame speed by 50%, and the flame length by 42% respectively, compared with those of the gas explosion of stoichiometric mixture. In this model, the effective raised dust concentrations to suppress explosion are 2.5-3.5 kg/m 3 . Copyright © 2018 Elsevier B.V. All rights reserved.

Geologic carbon storage is unlikely to trigger large earthquakes and reactivate faults through which CO2 could leak

PubMed Central

Vilarrasa, Victor; Carrera, Jesus

2015-01-01

Zoback and Gorelick [(2012) Proc Natl Acad Sci USA 109(26):10164–10168] have claimed that geologic carbon storage in deep saline formations is very likely to trigger large induced seismicity, which may damage the caprock and ruin the objective of keeping CO2 stored deep underground. We argue that felt induced earthquakes due to geologic CO2 storage are unlikely because (i) sedimentary formations, which are softer than the crystalline basement, are rarely critically stressed; (ii) the least stable situation occurs at the beginning of injection, which makes it easy to control; (iii) CO2 dissolution into brine may help in reducing overpressure; and (iv) CO2 will not flow across the caprock because of capillarity, but brine will, which will reduce overpressure further. The latter two mechanisms ensure that overpressures caused by CO2 injection will dissipate in a moderate time after injection stops, hindering the occurrence of postinjection induced seismicity. Furthermore, even if microseismicity were induced, CO2 leakage through fault reactivation would be unlikely because the high clay content of caprocks ensures a reduced permeability and increased entry pressure along the localized deformation zone. For these reasons, we contend that properly sited and managed geologic carbon storage in deep saline formations remains a safe option to mitigate anthropogenic climate change. PMID:25902501

Recombination device for storage batteries

DOEpatents

Kraft, H.; Ledjeff, K.

1984-01-01

A recombination device including a gas-tight enclosure connected to receive the discharge gases from a rechargeable storage battery. Catalytic material for the recombination of hydrogen and oxygen to form water is supported within the enclosure. The enclosure is sealed from the atmosphere by a liquid seal including two vertical chambers interconnected with an inverted U-shaped overflow tube. The first chamber is connected at its upper portion to the enclosure and the second chamber communicates at its upper portion with the atmosphere. If the pressure within the enclosure differs as overpressure or vacuum by more than the liquid level, the liquid is forced into one of the two chambers and the overpressure is vented or the vacuum is relieved. The recombination device also includes means for returning recombined liquid to the battery and for absorbing metal hydrides.

Recombination device for storage batteries

DOEpatents

Kraft, Helmut; Ledjeff, Konstantin

1985-01-01

A recombination device including a gas-tight enclosure connected to receive he discharge gases from a rechargeable storage battery. Catalytic material for the recombination of hydrogen and oxygen to form water is supported within the enclosure. The enclosure is sealed from the atmosphere by a liquid seal including two vertical chambers interconnected with an inverted U-shaped overflow tube. The first chamber is connected at its upper portion to the enclosure and the second chamber communicates at its upper portion with the atmosphere. If the pressure within the enclosure differs as overpressure or vacuum by more than the liquid level, the liquid is forced into one of the two chambers and the overpressure is vented or the vacuum is relieved. The recombination device also includes means for returning recombined liquid to the battery and for absorbing metal hydrides.

Blast overpressure after tire explosion: a fatal case.

PubMed

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

2013-12-01

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

Ares I-X Post Flight Ignition Overpressure Review

NASA Technical Reports Server (NTRS)

Alvord, David A.

2010-01-01

Ignition Overpressure (IOP) is an unsteady fluid flow and acoustic phenomena caused by the rapid expansion of gas from the rocket nozzle within a ducted launching space resulting in an initially higher amplitude pressure wave. This wave is potentially dangerous to the structural integrity of the vehicle. An in-depth look at the IOP environments resulting from the Ares I-X Solid Rocket Booster configuration showed high correlation between the pre-flight predictions and post-flight analysis results. Correlation between the chamber pressure and IOP transients showed successful acoustic mitigation, containing the strongest IOP waves below the Mobile Launch Pad deck. The flight data allowed subsequent verification and validation of Ares I-X unsteady fluid ducted launcher predictions, computational fluid dynamic models, and strong correlation with historical Shuttle data.

Mechanical study of the Chartreuse Fold-and-Thrust Belt: relationships between fluids overpressure and decollement within the Toarcian source-rock

NASA Astrophysics Data System (ADS)

Berthelon, Josselin; Sassi, William; Burov, Evgueni

2016-04-01

Many source-rocks are shale and constitute potential detachment levels in Fold-and-Thrust Belts (FTB): the toarcian Schistes-Cartons in the French Chartreuse FTB for example. Their mechanical properties can change during their burial and thermal maturation, as for example when large amount of hydrocarbon fluids are generated. A structural reconstruction of the Chartreuse FTB geo-history places the Toarcian Formation as the major decollement horizon. In this work, a mechanical analysis integrating the fluids overpressuring development is proposed to discuss on the validity of the structural interpretation. At first, an analogue of the Chartreuse Toarcian Fm, the albanian Posidonia Schist, is documented as it can provide insights on its initial properties and composition of its kerogen content. Laboratory characterisation documents the vertical evolution of the mineralogical, geochemical and mechanical parameters of this potential decollement layer. These physical parameters (i.e. Total Organic Carbon (TOC), porosity/permeability relationship, friction coefficient) are used to address overpressure buildup in the frontal part of the Chartreuse FTB with TEMISFlow Arctem Basin modelling approach (Faille et al, 2014) and the structural emplacement of the Chartreuse thrust units using the FLAMAR thermo-mechanical model (Burov et al, 2014). The hydro-mechanical modeling results highlight the calendar, distribution and magnitude of the overpressure that developed within the source-rock in the footwall of a simple fault-bend fold structure localized in the frontal part of the Chartreuse FTB. Several key geological conditions are required to create an overpressure able to fracture the shale-rocks and induce a significant change in the rheological behaviour: high TOC, low permeability, favourable structural evolution. These models highlight the importance of modeling the impact of a diffuse natural hydraulic fracturing to explain fluids propagation toward the foreland within the decollement layer. In turn, with the FLAMAR geo-mechanical models it is shown that for key mechanical parameters within the Chartreuse mechanical stratigraphy (such as friction coefficient, cohesion and viscosity properties), the mechanical boundary conditions to activate, localize and propagate shear thrust in the toarcian source-rock can be found to discuss on the hydro-mechanics of the structural evolution: the very weak mechanical properties that must be attributed to the source-rock to promote the formation of a decollement tend to justify the hypothesis of high fluids pressures in it. In FLAMAR, the evolution of the toarcian source-rock mechanical properties, calibrated on the temperature of kerogen-to-gas transformation, can be introduced to allow its activation as a decollement at a burial threshold. However, without hydro-mechanical coupling, it is not possible to predict where the overpressured regions that localised these changes are positioned. As such, this work also highlights the need for a fully-coupled hydro-mechanical model to further investigate the relationship between fluids and deformations in FTB and accretionary prisms. Burov, E., Francois, T., Yamato, P., & Wolf, S. (2014). Mechanisms of continental subduction and exhumation of HP and UHP rocks. Gondwana Research, 25(2), 464-493. Faille, I., Thibaut, M., Cacas, M.-C., Havé, P., Willien, F., Wolf, S., Agelas, L., Pegaz-Fiornet, S., 2014. Modeling Fluid Flow in Faulted Basins. Oil Gas Sci. Technol. - Rev. d'IFP Energies Nouv. 69, 529-553.

Estimation of the water retention curve from the soil hydraulic conductivity and sorptivity in an upward infiltration process

NASA Astrophysics Data System (ADS)

Moret-Fernández, David; Angulo, Marta; Latorre, Borja; González-Cebollada, César; López, María Victoria

2017-04-01

Determination of the saturated hydraulic conductivity, Ks, and the α and n parameters of the van Genuchten (1980) water retention curve, θ(h), are fundamental to fully understand and predict soil water distribution. This work presents a new procedure to estimate the soil hydraulic properties from the inverse analysis of a single cumulative upward infiltration curve followed by an overpressure step at the end of the wetting process. Firstly, Ks is calculated by the Darcy's law from the overpressure step. The soil sorptivity (S) is then estimated using the Haverkamp et al., (1994) equation. Next, a relationship between α and n, f(α,n), is calculated from the estimated Sand Ks. The α and n values are finally obtained by the inverse analysis of the experimental data after applying the f(α,n) relationship to the HYDRUS-1D model. The method was validated on theoretical synthetic curves for three different soils (sand, loam and clay), and subsequently tested on experimental sieved soils (sand, loam, clay loam and clay) of known hydraulic properties. A robust relationship was observed between the theoretical α and nvalues (R2 > 0.99) of the different synthetic soils and those estimated from inverse analysis of the upward infiltration curve. Consistent results were also obtained for the experimental soils (R2 > 0.85). These results demonstrated that this technique allowed accurate estimates of the soil hydraulic properties for a wide range of textures, including clay soils.

[An experimental study of blast injury].

PubMed

Wang, Z G

1989-01-01

This paper presents some aspects of the authors' experimental research on blast injury in the past two years. The main results are as follows: (1) A new designed 39 meter-long shock tube for biological test has been built in the laboratory. Its maximal overpressure values are 215 kPa (in open condition) and 505 kPa (in closed condition). It may meet the need for inflicting blast injuries with various degree of severity. (2) A study of the effect of simulating gun muzzle blast wave on sheep indicated that in the single explosion, the threshold overpressure values inflicting the injury of internal organs were: Lung-37.27 kPa, G-I tract-41.0 kPa; the upper respiratory tract-negative until 73 kPa, while in the multiple (20 times) explosions, they were 23.7, 23.7 and 41.4 kPa, respectively. (3) Using TEM, SEM and some other special techniques, such as morphometry, freeze-fracture technique, labelled lanthanum nitrate technique, etc, it was demonstrated that in the lung with blast injury there were significant pathological changes in pulmonary capillary endothelium, alveolar epithelium and their intercellular junctions with apparent increase of permeability. (4) It has been shown that parallel superficial stripelike hemorrhage typical for lung blast injury is "Intercostal marking" instead of "Rib marking". (5) A new type of material (foamy nickel) for protection against blast wave is presented. It was proved that the material can effectively weaken or eliminate the effect of blast wave on human body.

Helium bubbles aggravated defects production in self-irradiated copper

NASA Astrophysics Data System (ADS)

Wu, FengChao; Zhu, YinBo; Wu, Qiang; Li, XinZhu; Wang, Pei; Wu, HengAn

2017-12-01

Under the environment of high radiation, materials used in fission and fusion reactors will internally accumulate numerous lattice defects and bubbles. With extensive studies focused on bubble resolution under irradiation, the mutually effects between helium bubbles and displacement cascades in irradiated materials remain unaddressed. Therefore, the defects production and microstructure evolution under self-irradiation events in vicinity of helium bubbles are investigated by preforming large scale molecular dynamics simulations in single-crystal copper. When subjected to displacement cascades, distinguished bubble resolution categories dependent on bubble size are observed. With the existence of bubbles, radiation damage is aggravated with the increasing bubble size, represented as the promotion of point defects and dislocations. The atomic mechanisms of heterogeneous dislocation structures are attributed to different helium-vacancy cluster modes, transforming from the resolved gas trapped with vacancies to the biased absorption of vacancies by the over-pressured bubble. In both cases, helium impedes the recombination of point defects, leading to the accelerated formation of interstitial loops. The results and insight obtained here might contribute to understand the underlying mechanism of transmutant solute on the long-term evolution of irradiated materials.

Development of fluid overpressures in crustal faults and implications for earthquakes mechanics

NASA Astrophysics Data System (ADS)

Leclère, Henri; Cappa, Frédéric; Faulkner, Daniel; Armitage, Peter; Blake, Oshaine; Fabbri, Olivier

2013-04-01

The development and maintenance of fluid overpressures strongly influence the mechanical behavior of the crust and especially crustal fault zones. The mechanisms allowing fluid pressure build-up are still open questions, and their influence on tectonic and fault weakening processes remain unclear. The determination of the hydraulic and mechanical properties of crustal fault zone elements is a key aspect to improve our understanding of the fluid-tectonic interactions and more particularly the role of fluids in fault mechanics and earthquake triggering. Here we address this question combining geological observations, laboratory experiments and hydromechanical models of an active crustal fault-zone in the Ubaye-Argentera area (southeastern France). Previous studies showed that the fluids located in the fault zone developed overpressures between 7 and 26 MPa, that triggered intense seismic swarms (i.e. 16,000 events in 2003-2004) (Jenatton et al., 2007; Daniel et al., 2011; Leclère et al., 2012). The fault-zone studied here is located in the Argentera external crystalline massif and is connected to regional NW-SE steeply-dipping dextral strike-slip faults with an offset of several kilometers. The fault zone cuts through migmatitic gneisses composed of quartz, K-feldspar, plagioclase, biotite and minor muscovite. It exposes several anastomosed core zones surrounded by damage zones with a pluri-decametric total width. The core zones are made up of centimetric to pluridecimetric phyllosilicate-rich gouge layers while the damage zones are composed of pluri-metric phyllonitic rock derived from mylonite. The permeability and elastic moduli of the host rock, damage zone and fault core were measured from plugs with a diameter of 20 mm and lengths between 26 to 51 mm, using a high-pressure hydrostatic fluid-flow apparatus. Measurements were made with confining pressures ranging from 30 to 210 MPa and using argon pore fluid pressure of 20 MPa. Data show a variation of the permeability values of one order of magnitude between host rock and fault zone and a decrease of 50% of the elastic properties between host rock and core zone. The heterogeneity of properties is related to the development of different microstructures across the fault-zone during the tectonic history. From these physical property values and the fault zone architecture, we analyze the effects of sudden mechanical loading on the development of fluid overpressures in fault-zone. To do this, we use a series of 1-D hydromechanical numerical models to show that sudden mechanical stress increase is a viable mechanism for fluid overpressuring in fault-zone with spatially-varying elastic and hydraulic properties. Based on these results, we discuss the implications for earthquake triggering.on crustal-scale faults.

Tectonic overpressure may reconcile the structural and petrological records of the Adula nappe (Central Alps)

NASA Astrophysics Data System (ADS)

Pleuger, Jan; Podladchikov, Yuri

2014-05-01

The Penninic Alps are the result of progressive underthrusting of oceanic and continental domains below the Adriatic microplate. Situated in the internal part of the Alpine orogen, they expose basement and thinned cover nappes which have been metamorphosed to variable degree, among them several units which were subjected to ultrahigh-pressure metamorphism. Due to the more or less strong nappe-internal deformation of these units, cross sections through the Penninic Alps cannot be restored kinematically by area or line balancing techniques. Instead, such restorations attempt to consistently reconcile geochronological and structural data and petrological pressure-temperature estimates. Pressure data are usually converted into depth assuming that they were lithostatic which puts the ultrahigh-pressure units to subcrustal depths. Tectonic exhumation of a unit from such a depth by whatever mechanism requires a large-scale normal fault with several tens of kilometres of displacement in the hanging wall of the unit. However, for all Penninic ultrahigh-pressure units (Dora Maira unit, Zermatt-Saas zone, Monviso unit, Adula-Cima Lunga nappe), the oldest mappable post-peak-pressure structures are related to top-to-the-foreland shearing, i.e. thrusting. There are two potential solutions to this dilemma. The first one is that either the exhumation was indeed accommodated by a large-scale normal fault which became completely overprinted during later deformational stages. The other one is that peak pressures were not lithostatic. To our knowledge, the first solution is applied to all kinematic models of the Alps so far. In order to explore the feasibility of the second solution, we performed a purely structural restoration of the NFP20-East cross section without lithostatic pressure-to-depth-conversions. This cross-section comprises the ultrahigh-pressure Adula nappe (up to ca. 30 kbar) and relies on quantitative strain data from the overlying units. The result shows that, in accordance with the structural record, the Adula nappe can be restored to maximum depths of up to ca. 60 km. For individual points of the Adula nappe in the restored cross section, corresponding to the sporadic occurences of (ultra)high-pressure rocks, lithostatic pressures are exceeded by petrological peak-pressure data by about 40% to 80%. Such amounts of tectonic overpressure are within the limits of theoretical considerations and numerical modelling results. For the other units comprised in the cross section, and for subsequent tectono-metamorphic stages of the Adula nappe, negligible amounts of overpressure (around 10%) are determined from the restoration. We conclude that (1) the NFP20-East cross section can be kinematically restored by using only structural data, (2) the dilemma mentioned above can be solved by admitting realisting amounts of tectonic overpressure, and (3) significant amounts of overpressure were established only locally and episodically.

Glacially-derived overpressure in the northeastern Alaskan subduction zone: combined tomographic and morphometric analysis of shallow sediments on the Yakutat shelf and slope, Gulf of Alaska

NASA Astrophysics Data System (ADS)

Clary, W. A.; Worthington, L. L.; Scuderi, L. A.; Daigle, H.; Swartz, J. M.

2017-12-01

The Pamplona zone fold and thrust belt is the offshore expression of convergence and shallow subduction of the Yakutat microplate beneath North America in the northeastern Alaska subduction zone. The combination of convergent tectonics and glaciomarine sedimentary processes create patterns of deformation and deposition resulting in a shallow sedimentary sequence with varying compaction, fluid pressure, and fault activity. We propose that velocity variations observed in our tomographic analysis represent long-lived fluid overpressure due to loading by ice sheets and sediments. Regions with bathymetric and stratigraphic evidence of recent ice sheets and associated sedimentation should be collocated with evidence of overpressure (seismic low velocity zones) in the shallow sediments. Here, we compare a velocity model with shelf seismic stratigraphic facies and modern seafloor morphology. To document glacially derived morphology we use high resolution bathymetry to identify channel and gully networks on the western Yakutat shelf-slope then analyze cross-channel shape indices across the study area. We use channel shape index measurements as a proxy of recent ice-proximal sedimentation based on previously published results that proposed a close correlation. Profiles taken at many locations were fitted with a power function and assigned a shape - U-shape channels likely formed proximal to recent ice advances. Detailed velocity models were created by a combination of streamer tomography and pre-stack depth migration velocities with seismic data including: a 2008 R/V Langseth dataset from the St. Elias Erosion and Tectonics Project (STEEP); and a 2004 high-resolution R/V Ewing dataset. Velocity-porosity-permeability relationships developed using IODP Expedition 341 drilling data inform interpretation and physical properties analyses of the shallow sediments. Initial results from a 35 km profile extending SE seaward of the Bering glacier and subparallel to the Bering trough suggest a spatial relationship between the extent of U-shaped profiles and low-velocity shallow sediments. Towards the SE end of the model we observe a large overlap of U-shaped indices, and a shallow low-velocity zone in the mapped extent of the last glacial maximum suggestive of overpressure due to loading by ice sheet activity.

Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska 1. Origin of Strombolian activity

USGS Publications Warehouse

Vergniolle, S.; Boichu, M.; Caplan-Auerbach, J.

2004-01-01

The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) displayed both classical Strombolian activity and an explosive Subplinian plume. Strombolian activity at Shishaldin occurred in two major phases following the Subplinian activity. In this paper, we use acoustic measurements to interpret the Strombolian activity. Acoustic measurements of the two Strombolian phases show a series of explosions that are modeled by the vibration of a large overpressurised cylindrical bubble at the top of the magma column. Results show that the bubble does not burst at its maximum radius, as expected if the liquid film is stretched beyond its elasticity. But bursting occurs after one cycle of vibration, as a consequence of an instability of the air-magma interface close to the bubble minimum radius. During each Strombolian period, estimates of bubble length and overpressure are calculated. Using an alternate method based on acoustic power, we estimate gas velocity to be 30-60 m/s, in very good agreement with synthetic waveforms. Although there is some variation within these parameters, bubble length and overpressure for the first Strombolian phase are found to be ??? 82 ?? 11 m and 0.083 MPa. For the second Strombolian phase, bubble length and overpressure are estimated at 24 ?? 12 m and 0.15 MPa for the first 17 h after which bubble overpressure shows a constant increase, reaching a peak of 1.4 MPa, just prior to the end of the second Strombolian phase. This peak suggests that, at the time, the magma in the conduit may contain a relatively large concentration of small bubbles. Maximum total gas volume and gas fluxes at the surface are estimated to be 3.3 ?? 107 and 2.9 ?? 103 m3/s for the first phase and 1.0 ?? 108 and 2.2 ?? 103 m3/s for the second phase. This gives a mass flux of 1.2 ?? 103 and 8.7 ?? 102 kg/s, respectively, for the first and the second Strombolian phases. ?? 2004 Elsevier B.V. All rights reserved.

Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska 2. Precursor to the Subplinian phase

USGS Publications Warehouse

Vergniolle, S.; Caplan-Auerbach, J.

2004-01-01

The 1999 eruption of Shishaldin volcano (Alaska, USA) displayed both Strombolian and Subplinian basaltic activity. The Subplinian phase was preceded by a signal of low amplitude and constant frequency (??? 2 Hz) lasting 13 h. This "humming signal" is interpreted as the coalescence of the very shallow part of a foam building up in the conduit, which produces large gas bubbles before bursting. The acoustic waveform of the hum event is modelled by a Helmholtz resonator: gas is trapped into a rigid cavity and can only escape through a tiny upper hole producing sound waves. At Shishaldin, the radius of the hole (??? 5 m) is close to that of the conduit (??? 6 m), the cavity has a length of ??? 60 m, and gas presents only a small overpressure between (??? 1.2 ?? 10-3 and 4.5 ?? 10-3 MPa). Such an overpressure is obtained by the partial coalescence of a foam formed by bubbles with a diameter from ??? 2.3 mm at the beginning of the episode towards ??? 0.64 mm very close to the end of the phase. The intermittency between hum events is explained by the ripening of the foam induced by the H2O diffusion through the liquid films. The two extreme values, from 600 to 10 s, correspond to a bubble diameter from 2.2 to 0.3 mm at the beginning and end of the pre-Subplinian phase, respectively. The extremely good agreement between two independent estimates of bubble diameters in the shallow foam reinforces the validity of such an interpretation. The total gas volume lost at the surface during the humming events is at most 5.9 ?? 106 m3. At the very end of the pre-Subplinian phase, there is a single large bubble with an overpressure of ???0.42 MPa. The large overpressure suggests that it comes from significant depth, unlike other bubbles in the pre-Subplinian phase. This deep bubble may be responsible for the entire foam collapse, resulting in the Subplinian phase. ?? 2004 Elsevier B.V. All rights reserved.

Mechanical damage of tympanic membrane in relation to impulse pressure waveform - A study in chinchillas.

PubMed

Gan, Rong Z; Nakmali, Don; Ji, Xiao D; Leckness, Kegan; Yokell, Zachary

2016-10-01

Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded with a stainless steel cup covering the animal head. Auditory brainstem response (ABR) and wideband tympanometry were measured before and after exposure to check the hearing threshold and middle ear function. Results show that waveforms recorded in the shielded case were different from those in the open field and the TM rupture threshold in the shielded case was lower than that in the open field (3.4 ± 0.7 vs. 9.1 ± 1.7 psi or 181 ± 1.6 vs. 190 ± 1.9 dB SPL). The impulse pressure energy spectra analysis of waveforms demonstrates that the shielded waveforms include greater energy at high frequencies than that of the open field waves. Finally, a 3D finite element (FE) model of the chinchilla ear was used to compute the distributions of stress in the TM and the TM displacement with impulse pressure waves. The FE model-derived change of stress in response to pressure loading in the shielded case was substantially faster than that in the open case. This finding provides the biomechanical mechanisms for blast induced TM damage in relation to overpressure waveforms. The TM rupture threshold difference between the open and shielded cases suggests that an acoustic role of helmets may exist, intensifying ear injury during blast exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluid Overpressure and Earthquakes Triggering in the Natural Laboratory of the Northern Apennines: Integration of Field and Laboratory Data

NASA Astrophysics Data System (ADS)

de Paola, N.; Collettini, C.; Faulkner, D.

2007-12-01

The integration of seismic reflection profiles with well-located earthquakes show that the mainshocks of the 1997-1998 Colfiorito seismic sequence (Central Italy) nucleated at a depth of ~6 km within the Triassic Evaporites (TE, anhydrites and dolostones), where CO2 at near lithostatic pressure has been encountered in two deep boreholes (4 km). In order to investigate the deformation processes operating at depth in the source region of the Colfiorito earthquakes we have characterized: 1) fault zone structure by studying exhumed outcrops of the temperature, 100 MPa confining pressure (Pc), and range of pore fluid pressures (Pf). Permeability and porosity development was continuously measured throughout the deformation experiments. The architecture of large fault zones within the TE is given by a distinct fault core, where most of the shear strain has been accommodated, surrounded by a geometrically complex and heterogeneous damage zone. Brittle deformation within the fault core is extremely localized along principal slip surfaces associated with dolomite rich cataclasite seams, running parallel to the fault zone. The damage zone is characterized by adjacent zones of heavily fractured rocks (dolostones) and foliated rocks displaying little fracturing (anhydrites). Static permeability measurements on anhydrite samples show increasing values of permeability for decreasing values of Pe, (k = 10E-20 - 10E-22 m2). During single cycle loading tests the permeability values immediately prior to failure are about three orders of magnitude higher than the initial values. The field data suggests that during the seismic cycle, the permeability of the dolostones, within the damage zone, is likely to be high and controlled by mesoscale fracture patterns. Conversely, the permeability of the anhydrites, due to the absence of mesoscale fracture patterns within Ca-sulphates layers, may be potentially as low as the values measured in the lab experiments (k = 10E-17 - 10E-22 m2). This suggests that fluid overpressure can be maintained in this lithology, within the damage zone, as far as the co-seismic period. Our observations and results can be applied to explain the seismicity of the Northern Apennines and other regions where fluids overpressures play a key role in triggering fault instability and earthquakes.

Fluid Overpressure and Earthquakes Triggering in the Natural Laboratory of the Northern Apennines: Integration of Field and Laboratory Data

NASA Astrophysics Data System (ADS)

de Paola, N.; Collettini, C.; Faulkner, D.

2004-12-01

The integration of seismic reflection profiles with well-located earthquakes show that the mainshocks of the 1997-1998 Colfiorito seismic sequence (Central Italy) nucleated at a depth of ~6 km within the Triassic Evaporites (TE, anhydrites and dolostones), where CO2 at near lithostatic pressure has been encountered in two deep boreholes (4 km). In order to investigate the deformation processes operating at depth in the source region of the Colfiorito earthquakes we have characterized: 1) fault zone structure by studying exhumed outcrops of the temperature, 100 MPa confining pressure (Pc), and range of pore fluid pressures (Pf). Permeability and porosity development was continuously measured throughout the deformation experiments. The architecture of large fault zones within the TE is given by a distinct fault core, where most of the shear strain has been accommodated, surrounded by a geometrically complex and heterogeneous damage zone. Brittle deformation within the fault core is extremely localized along principal slip surfaces associated with dolomite rich cataclasite seams, running parallel to the fault zone. The damage zone is characterized by adjacent zones of heavily fractured rocks (dolostones) and foliated rocks displaying little fracturing (anhydrites). Static permeability measurements on anhydrite samples show increasing values of permeability for decreasing values of Pe, (k = 10E-20 - 10E-22 m2). During single cycle loading tests the permeability values immediately prior to failure are about three orders of magnitude higher than the initial values. The field data suggests that during the seismic cycle, the permeability of the dolostones, within the damage zone, is likely to be high and controlled by mesoscale fracture patterns. Conversely, the permeability of the anhydrites, due to the absence of mesoscale fracture patterns within Ca-sulphates layers, may be potentially as low as the values measured in the lab experiments (k = 10E-17 - 10E-22 m2). This suggests that fluid overpressure can be maintained in this lithology, within the damage zone, as far as the co-seismic period. Our observations and results can be applied to explain the seismicity of the Northern Apennines and other regions where fluids overpressures play a key role in triggering fault instability and earthquakes.

49 CFR 192.195 - Protection against accidental overpressuring.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of §§ 192.199 and 192.201. (b) Additional requirements for distribution systems. Each distribution..., load, and other service conditions that will be experienced in normal operation of the system, and that...

Low-temperature overpressurization protection system setpoint analysis using RETRAN-02/MOD5 for Salem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dodson, R.J.; Feltus, M.A.

The low-temperature overpressurization protection system (LTOPS) is designed to protect the reactor pressure vessel (RPV) from brittle failure during startup and cooldown maneuvers in Westinghouse pressurized water reactors. For the Salem power plants, the power-operated relief valves (PORVs) mitigate pressure increases above a setpoint where an operational startup transient may put the RPV in the embrittlement fracture zone. The Title 10, Part 50, Code of Federal Regulations Appendix G limit, given by plant technical specifications, conservatively bounds the maximum pressure allowed during those transients where the RPV can suffer brittle fracture (usually below 350{degrees}F). The Appendix G limit is amore » pressure versus temperature curve that is more restrictive at lower RPV temperatures and allows for higher pressures as the temperature approaches the upper bounding fracture temperature.« less

Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

DOE PAGES

Nole, Michael; Daigle, Hugh; Cook, Ann E.; ...

2016-08-31

Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Here, short-range advective migration can increase the amount of methane delivered to sands as compared tomore » the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.« less

Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nole, Michael; Daigle, Hugh; Cook, Ann E.

Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Here, short-range advective migration can increase the amount of methane delivered to sands as compared tomore » the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.« less

Experimental Study of the Effect of Water Mist Location On Blast Overpressure Attenuation in A Shock Tube

NASA Astrophysics Data System (ADS)

Mataradze, Edgar; Chikhradze, Nikoloz; Bochorishvili, Nika; Akhvlediani, Irakli; Tatishvili, Dimitri

2017-12-01

Explosion protection technologies are based on the formation of a shock wave mitigation barrier between the protection site and the explosion site. Contemporary protective systems use water mist as an extinguishing barrier. To achieve high effectiveness of the protective system, proper selection of water mist characteristics is important. The main factors defining shock wave attenuation in water mist include droplet size distribution, water concentration in the mist, droplet velocity and geometric properties of mist. This paper examines the process of attenuation of shock waves in mist with droplets ranging from 25 to 400 microns under different conditions of water mist location. Experiments were conducted at the Mining Institute with the use of a shock tube to study the processes of explosion suppression by a water mist barrier. The shock tube consists of a blast chamber, a tube, a system for the dosed supply of water, sensors, data recording equipment, and a process control module. Shock wave overpressure reduction coefficient was studied in the shock tube under two different locations of water mist: a) when water mist is created in direct contact with blast chamber and b) the blast chamber and the mist are separated by air space. It is established that in conditions when the air space distance between the blast chamber and the mist is 1 meter, overpressure reduction coefficient is 1.5-1.6 times higher than in conditions when water mist is created in direct contact with blast chamber.

Acoustic Full Waveform Inversion to Characterize Near-surface Chemical Explosions

NASA Astrophysics Data System (ADS)

Kim, K.; Rodgers, A. J.

2015-12-01

Recent high-quality, atmospheric overpressure data from chemical high-explosive experiments provide a unique opportunity to characterize near-surface explosions, specifically estimating yield and source time function. Typically, yield is estimated from measured signal features, such as peak pressure, impulse, duration and/or arrival time of acoustic signals. However, the application of full waveform inversion to acoustic signals for yield estimation has not been fully explored. In this study, we apply a full waveform inversion method to local overpressure data to extract accurate pressure-time histories of acoustics sources during chemical explosions. A robust and accurate inversion technique for acoustic source is investigated using numerical Green's functions that take into account atmospheric and topographic propagation effects. The inverted pressure-time history represents the pressure fluctuation at the source region associated with the explosion, and thus, provides a valuable information about acoustic source mechanisms and characteristics in greater detail. We compare acoustic source properties (i.e., peak overpressure, duration, and non-isotropic shape) of a series of explosions having different emplacement conditions and investigate the relationship of the acoustic sources to the yields of explosions. The time histories of acoustic sources may refine our knowledge of sound-generation mechanisms of shallow explosions, and thereby allow for accurate yield estimation based on acoustic measurements. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Jonah field, sublette county, Wyoming: Gas production from overpressured Upper Cretaceous Lance sandstones of the Green River basin

USGS Publications Warehouse

Montgomery, S.L.; Robinson, J.W.

1997-01-01

Jonah field, located in the northwestern Green River basin, Wyoming, produces gas from overpressured fluvial channel sandstones of the Upper Cretaceous Lance Formation. Reservoirs exist in isolated and amalgamated channel facies 10-100 ft (3-30 m) thick and 150-4000 ft (45-1210 m) wide, deposited by meandering and braided streams. Compositional and paleocurrent studies indicate these streams flowed eastward and had their source area in highlands associated with the Wyoming-Idaho thrust belt to the west. Productive sandstones at Jonah have been divided into five pay intervals, only one of which (Jonah interval) displays continuity across most of the field. Porosities in clean, productive sandstones range from 8 to 12%, with core permeabilities of .01-0.9 md (millidarcys) and in-situ permeabilities as low as 3-20 ??d (microdarcys), as determined by pressure buildup analyses. Structurally, the field is bounded by faults that have partly controlled the level of overpressuring. This level is 2500 ft (758 m) higher at Jonah field than in surrounding parts of the basin, extending to the top part of the Lance Formation. The field was discovered in 1975, but only in the 1990s did the area become fully commercial, due to improvements in fracture stimulation techniques. Recent advances in this area have further increased recoverable reserves and serve as a potential example for future development of tight gas sands elsewhere in the Rocky Mountain region.

Abnormal organic-matter maturation in the Yinggehai Basin, South China Sea: Implications for hydrocarbon expulsion and fluid migration from overpressured systems

USGS Publications Warehouse

Hao, F.; Li, S.; Dong, W.; Hu, Z.; Huang, B.

1998-01-01

Three superimposed pressure systems are present in the Yinggehai Basin, South China Sea. A number of commercial, thermogenic gas accumulations have been found in an area in which shale diapirs occur. Because the reservoir intervals are shallow and very young, they must have filled with gas rapidly. The thick (up to 17 km) Tertiary and Quaternary sedimentary succession is dominated by shales, and is not disrupted by major faulting in the study area, a factor which seems to have had an important effect on both hydrocarbon generation and fluid migration. Organic-matter maturation in the deepest, most overpressured compartment has been significantly retarded as a result of the combined effects of excess pressure, the presence of large volumes of water, and the retention of generated hydrocarbons. This retardation is indicated by both kerogen-related parameters (vitrinite reflectance and Rock-Eval T(max)); and also by parameters based on the analysis of soluble organic matter (such as the C15+ hydrocarbon content, and the concentration of isoprenoid hydrocarbons relative to adjacent normal alkanes). In contrast to this, organic-matter maturation in shallow, normally-pressured strata in the diapiric area has been enhanced by hydrothermal fluid flow, which is clearly not topography-driven in origin. As a result, the hydrocarbon generation 'window' in the basin is considerably wider than could be expected from traditional geochemical modelling. These two unusual and contrasting anomalies in organic-matter maturation, together with other lines of evidence, suggest that there was a closed fluid system in the overpressured compartment until shale diapirs developed. The diapirs developed as a result of the intense overpressuring, and their growth was triggered by regional extensional stresses. They served as conduits through which fluids (both water and hydrocarbons) retained in the closed system could rapidly migrate. Fluid migration led to the modification of the thermal regime and the enhancement of organic maturation, as well as the accumulation of commercial volumes of gas in a relatively short time interval.Three superimposed pressure systems are present in the Yinggehai Basin, South China Sea. To date, a number of commercial, thermogenic gas accumulations have been found in an area in which shale diapirs occur. In fact, two unusual and contrasting anomalies in organic-matter maturation have been documented. These two anomalies, together with other lines of evidence, suggest that there was a closed fluid system in the overpressured compartment until shale diapirs developed. The diapirs developed as a result of intense overpowering, and their growth was triggered by regional extensional stresses. They served as conduits through which fluids retained in the closed system could rapidly migrate. Fluid migration led to the modification of the thermal regime and the enhancement of organic maturation, as well as the accumulation of commercial volumes of gas in a relatively short time interval.

Ground Measurements of Airplane Shock-Wave Noise at Mach Numbers to 2.0 and at Altitudes to 60,000 Feet

NASA Technical Reports Server (NTRS)

Lina, Lindsay J.; Maglieri, Domenic J.

1960-01-01

The intensity of shock-wave noise at the ground resulting from flights at Mach numbers to 2.0 and altitudes to 60,000 feet was measured. Meagurements near the ground track for flights of a supersonic fighter and one flight of a supersonic bomber are presented. Level cruising flight at an altitude of 60,000 feet and a Mach number of 2.0 produced sonic booms which were considered to be tolerable, and it is reasonable t o expect that cruising flight at higher altitudes will produce booms of tolerable intensity for airplanes of the size and weight of the test airplanes. The measured variation of sonic-boom intensity with altitude was in good agreement with the variation calculated by an equation given in NASA Technical Note D-48. The effect of Mach number on the ground overpressure is small between Mach numbers of 1.4 and 2.0, a result in agreement with the theory. No amplification of the shock-wave overpressures due to refraction effects was apparent near the cutoff Mach number. A method for estimating the effect of fligh-path angle on cutoff Mach number is shown. Experimental results indicate agreement with the method, since a climb maneuver produced booms of a much decreased intensity as compared with the intensity of those measured in level flight at about the same altitude and Mach number. Comparison of sound pressure levels for the fighter and bomber airp lanes indicated little effect of either airplane size or weight at an altitude of 40,000 feet.

Influence of Shell Properties on High-Frequency Ultrasound Imaging and Drug Delivery Using Polymer-Shelled Microbubbles

PubMed Central

Chitnis, Parag V.; Koppolu, Sujeethraj; Mamou, Jonathan; Chlon, Ceciel; Ketterling, Jeffrey A.

2013-01-01

This two-part study investigated shell rupture of ultrasound contrast agents (UCAs) under static overpressure conditions and the subharmonic component from UCAs subjected to 20-MHz tonebursts. Five different polylactide-shelled UCAs with shell-thickness-to-radius ratios (STRRs) of 7.5, 30, 40, 65, and 100 nm/μm were subjected to static overpressure in a glycerol-filled test chamber. A video microscope imaged the UCAs as pressure varied from 2 to 330 kPa over 90 min. Images were postprocessed to obtain the pressure threshold for rupture and the diameter of individual microbubbles. Backscatter from individual UCAs was investigated by flowing a dilute UCA solution through a wall-less flow phantom placed at the geometric focus of a 20-MHz transducer. UCAs were subjected to 10- and 20-cycle tonebursts of acoustic pressures ranging from 0.3 to 2.3 MPa. A method based on singular-value decomposition (SVD) was employed to obtain a cumulative subharmonic score (SHS). Different UCA types exhibited distinctly different rupture thresholds that were linearly related to their STRR, but uncorrelated with UCA size. The rupture threshold for the UCAs with an STRR = 100 nm/μm was more than 4 times greater than the UCAs with an STRR = 7.5 nm/μm. The polymer-shelled UCAs produced substantial subharmonic response but the subharmonic response to 20-MHz excitation did not correlate with STRRs or UCA-rupture pressures. The 20-cycle excitation resulted in an SHS that was 2 to 3 times that of UCAs excited with 10-cycle tonebursts. PMID:23287913

Ground signature extrapolation of three-dimensional near-field CFD predictions for several HSCT configurations

NASA Technical Reports Server (NTRS)

Siclari, M. J.

1992-01-01

A CFD analysis of the near-field sonic boom environment of several low boom High Speed Civilian Transport (HSCT) concepts is presented. The CFD method utilizes a multi-block Euler marching code within the context of an innovative mesh topology that allows for the resolution of shock waves several body lengths from the aircraft. Three-dimensional pressure footprints at one body length below three-different low boom aircraft concepts are presented. Models of two concepts designed by NASA to cruise at Mach 2 and Mach 3 were built and tested in the wind tunnel. The third concept was designed by Boeing to cruise at Mach 1.7. Centerline and sideline samples of these footprints are then extrapolated to the ground using a linear waveform parameter method to estimate the ground signatures or sonic boom ground overpressure levels. The Mach 2 concept achieved its centerline design signature but indicated higher sideline booms due to the outboard wing crank of the configuration. Nacelles are also included on two of NASA's low boom concepts. Computations are carried out for both flow-through nacelles and nacelles with engine exhaust simulation. The flow-through nacelles with the assumption of zero spillage and zero inlet lip radius showed very little effect on the sonic boom signatures. On the other hand, it was shown that the engine exhaust plumes can have an effect on the levels of overpressure reaching the ground depending on the engine operating conditions. The results of this study indicate that engine integration into a low boom design should be given some attention.

Computational Analysis of a Low-Boom Supersonic Inlet

NASA Technical Reports Server (NTRS)

Chima, Rodrick V.

2011-01-01

A low-boom supersonic inlet was designed for use on a conceptual small supersonic aircraft that would cruise with an over-wing Mach number of 1.7. The inlet was designed to minimize external overpressures, and used a novel bypass duct to divert the highest shock losses around the engine. The Wind-US CFD code was used to predict the effects of capture ratio, struts, bypass design, and angles of attack on inlet performance. The inlet was tested in the 8-ft by 6-ft Supersonic Wind Tunnel at NASA Glenn Research Center. Test results showed that the inlet had excellent performance, with capture ratios near one, a peak core total pressure recovery of 96 percent, and a stable operating range much larger than that of an engine. Predictions generally compared very well with the experimental data, and were used to help interpret some of the experimental results.

Brain Vulnerability to Repeated Blast Overpressure and Polytrauma

DTIC Science & Technology

2012-05-01

shock tube: distinguishing primary and tertiary blast injury mechanisms in rat TBI - Roles of polyunsaturated fatty acids in traumatic brain injury...vulnerabilities and resilience: evaluation of salutary effects of DHA supplementation using neurolipidomics and functional outcome assessments

Fabrication of micromachined ceramic thin-film-type pressure sensors for overpressure tolerance and its characteristics

NASA Astrophysics Data System (ADS)

Chung, Gwiy-Sang; Kim, Jae-Min

2004-04-01

This paper describes the fabrication process and characteristics of ceramic thin-film pressure sensors based on Ta-N strain gauges for harsh environment applications. The Ta-N thin-film strain gauges are sputter-deposited on a thermally oxidized micromachined Si diaphragm with buried cavities for overpressure tolerance. The proposed device takes advantage of the good mechanical properties of single-crystalline Si as a diaphragm fabricated by SDB and electrochemical etch-stop technology, and in order to extend the temperature range, it has relatively higher resistance, stability and gauge factor of Ta-N thin-films more than other gauges. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low nonlinearity and excellent temperature stability. The sensitivity is 1.21-1.097 mV/V×kgf/cm2 in temperature ranges of 25-200°C and a maximum non-linearity is 0.43 %FS.

Shock wave propagation within a confined multi-chamber system

NASA Astrophysics Data System (ADS)

Julien, B.; Sochet, I.; Tadini, P.; Vaillant, T.

2018-07-01

The influence of a variation of the opening ratios of rooms and side walls on the propagation of a shock wave within a confined multi-chamber system is analyzed through the evolution of some of the shock parameters (maximum overpressure and positive impulse). The shock wave is generated by the detonation of a hemispherical gaseous charge in one of the rooms. Several small-scale experiments have been carried out using an adjustable model representative of a pyrotechnic workshop. Using the same approach as for a previous article dealing with the impact of the volume of the rooms, we were able to link the evolution of the arrival time of the shock wave within the building with the reference obtained in the free field. Moreover, using a new parameter taking into account the opening ratios of the rooms and side walls, a predictive law was developed to model the maximal overpressure in the rooms.

Applicability of preparative overpressured layer chromatography and direct bioautography in search of antibacterial chamomile compounds.

PubMed

Móricz, Agnes M; Ott, Péter G; Alberti, Agnes; Böszörményi, Andrea; Lemberkovics, Eva; Szoke, Eva; Kéry, Agnes; Mincsovics, Emil

2013-01-01

In situ sample preparation and preparative overpressured layer chromatography (OPLC) fractionation on a 0.5 mm thick adsorbent layer of chamomile flower methanol extract prepurified by conventional gravitation accelerated column chromatography were applied in searching for bioactive components. Sample cleanup in situ on the adsorbent layer subsequent to sample application was performed using mobile phase flow in the opposite direction (the input and output of the eluent was exchanged). The antibacterial effect of the fractions obtained from the stepwise gradient OPLC separation with the flow in the normal direction was evaluated by direct bioautography against two Gram-negative bacteria: the luminescence gene tagged plant pathogenic Pseudomonas syringae pv. maculicola, and the naturally luminescent marine bacterium Vibrio fischeri. The fractions having strong activity were analyzed by SPME-GC/MS and HPLC/MS/MS. Mainly essential oil components, coumarins, flavonoids, phenolic acids, and fatty acids were tentatively identified in the fractions.

Integrated Geothermal-CO2 Storage Reservoirs: FY1 Final Report

DOE Data Explorer

Buscheck, Thomas A.

2012-01-01

The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. This submittal contains input and output files of the reservoir model analyses. A reservoir-model "index-html" file was sent in a previous submittal to organize the reservoir-model input and output files according to sections of the FY1 Final Report to which they pertain. The recipient should save the file: Reservoir-models-inputs-outputs-index.html in the same directory that the files: Section2.1.*.tar.gz files are saved in.

Long-term thermal effects on injectivity evolution during CO 2 storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vilarrasa, Victor; Rinaldi, Antonio P.; Rutqvist, Jonny

Carbon dioxide (CO 2 ) is likely to reach the bottom of injection wells at a colder temperature than that of the storage formation, causing cooling of the rock. This cooling, together with overpressure, tends to open up fractures, which may enhance injectivity. Here, we investigate cooling effects on injectivity enhancement by modeling the In Salah CO 2 storage site and a theoretical, long-term injection case. We use stress-dependent permeability functions that predict an increase in permeability as the effective stress acting normal to fractures decreases. Normal effective stress can decrease either due to overpressure or cooling. We calibrate ourmore » In Salah model, which includes a fracture zone perpendicular to the well, obtaining a good fitting with the injection pressure measured at KB-502 and the rapid CO 2 breakthrough that occurred at the observation well KB-5 located 2 km away from the injection well. CO 2 preferentially advances through the fracture zone, which becomes two orders of magnitude more permeable than the rest of the reservoir. Nevertheless, the effect of cooling on the long-term injectivity enhancement is limited in pressure dominated storage sites, like at In Salah, because most of the permeability enhancement is due to overpressure. But, thermal effects enhance injectivity in cooling dominated storage sites, which may decrease the injection pressure by 20%, saving a significant amount of compression energy all over the duration of storage projects. Overall, our simulation results show that cooling has the potential to enhance injectivity in fractured reservoirs.« less

Uncertainty quantification of overpressure buildup through inverse modeling of compaction processes in sedimentary basins

NASA Astrophysics Data System (ADS)

Colombo, Ivo; Porta, Giovanni M.; Ruffo, Paolo; Guadagnini, Alberto

2017-03-01

This study illustrates a procedure conducive to a preliminary risk analysis of overpressure development in sedimentary basins characterized by alternating depositional events of sandstone and shale layers. The approach rests on two key elements: (1) forward modeling of fluid flow and compaction, and (2) application of a model-complexity reduction technique based on a generalized polynomial chaos expansion (gPCE). The forward model considers a one-dimensional vertical compaction processes. The gPCE model is then used in an inverse modeling context to obtain efficient model parameter estimation and uncertainty quantification. The methodology is applied to two field settings considered in previous literature works, i.e. the Venture Field (Scotian Shelf, Canada) and the Navarin Basin (Bering Sea, Alaska, USA), relying on available porosity and pressure information for model calibration. It is found that the best result is obtained when porosity and pressure data are considered jointly in the model calibration procedure. Uncertainty propagation from unknown input parameters to model outputs, such as pore pressure vertical distribution, is investigated and quantified. This modeling strategy enables one to quantify the relative importance of key phenomena governing the feedback between sediment compaction and fluid flow processes and driving the buildup of fluid overpressure in stratified sedimentary basins characterized by the presence of low-permeability layers. The results here illustrated (1) allow for diagnosis of the critical role played by the parameters of quantitative formulations linking porosity and permeability in compacted shales and (2) provide an explicit and detailed quantification of the effects of their uncertainty in field settings.

Rodent model of direct cranial blast injury.

PubMed

Kuehn, Reed; Simard, Philippe F; Driscoll, Ian; Keledjian, Kaspar; Ivanova, Svetlana; Tosun, Cigdem; Williams, Alicia; Bochicchio, Grant; Gerzanich, Volodymyr; Simard, J Marc

2011-10-01

Traumatic brain injury resulting from an explosive blast is one of the most serious wounds suffered by warfighters, yet the effects of explosive blast overpressure directly impacting the head are poorly understood. We developed a rodent model of direct cranial blast injury (dcBI), in which a blast overpressure could be delivered exclusively to the head, precluding indirect brain injury via thoracic transmission of the blast wave. We constructed and validated a Cranium Only Blast Injury Apparatus (COBIA) to deliver blast overpressures generated by detonating .22 caliber cartridges of smokeless powder. Blast waveforms generated by COBIA replicated those recorded within armored vehicles penetrated by munitions. Lethal dcBI (LD(50) ∼ 515 kPa) was associated with: (1) apparent brainstem failure, characterized by immediate opisthotonus and apnea leading to cardiac arrest that could not be overcome by cardiopulmonary resuscitation; (2) widespread subarachnoid hemorrhages without cortical contusions or intracerebral or intraventricular hemorrhages; and (3) no pulmonary abnormalities. Sub-lethal dcBI was associated with: (1) apnea lasting up to 15 sec, with transient abnormalities in oxygen saturation; (2) very few delayed deaths; (3) subarachnoid hemorrhages, especially in the path of the blast wave; (4) abnormal immunolabeling for IgG, cleaved caspase-3, and β-amyloid precursor protein (β-APP), and staining for Fluoro-Jade C, all in deep brain regions away from the subarachnoid hemorrhages, but in the path of the blast wave; and (5) abnormalities on the accelerating Rotarod that persisted for the 1 week period of observation. We conclude that exposure of the head alone to severe explosive blast predisposes to significant neurological dysfunction.

Frictional stability and earthquake triggering during fluid pressure stimulation of an experimental fault

NASA Astrophysics Data System (ADS)

Scuderi, M. M.; Collettini, C.; Marone, C.

2017-11-01

It is widely recognized that the significant increase of M > 3.0 earthquakes in Western Canada and the Central United States is related to underground fluid injection. Following injection, fluid overpressure lubricates the fault and reduces the effective normal stress that holds the fault in place, promoting slip. Although, this basic physical mechanism for earthquake triggering and fault slip is well understood, there are many open questions related to induced seismicity. Models of earthquake nucleation based on rate- and state-friction predict that fluid overpressure should stabilize fault slip rather than trigger earthquakes. To address this controversy, we conducted laboratory creep experiments to monitor fault slip evolution at constant shear stress while the effective normal stress was systematically reduced via increasing fluid pressure. We sheared layers of carbonate-bearing fault gouge in a double direct shear configuration within a true-triaxial pressure vessel. We show that fault slip evolution is controlled by the stress state acting on the fault and that fluid pressurization can trigger dynamic instability even in cases of rate strengthening friction, which should favor aseismic creep. During fluid pressurization, when shear and effective normal stresses reach the failure condition, accelerated creep occurs in association with fault dilation; further pressurization leads to an exponential acceleration with fault compaction and slip localization. Our work indicates that fault weakening induced by fluid pressurization can overcome rate strengthening friction resulting in fast acceleration and earthquake slip. Our work points to modifications of the standard model for earthquake nucleation to account for the effect of fluid overpressure and to accurately predict the seismic risk associated with fluid injection.

Long-term thermal effects on injectivity evolution during CO 2 storage

DOE PAGES

Vilarrasa, Victor; Rinaldi, Antonio P.; Rutqvist, Jonny

2017-08-22

Carbon dioxide (CO 2 ) is likely to reach the bottom of injection wells at a colder temperature than that of the storage formation, causing cooling of the rock. This cooling, together with overpressure, tends to open up fractures, which may enhance injectivity. Here, we investigate cooling effects on injectivity enhancement by modeling the In Salah CO 2 storage site and a theoretical, long-term injection case. We use stress-dependent permeability functions that predict an increase in permeability as the effective stress acting normal to fractures decreases. Normal effective stress can decrease either due to overpressure or cooling. We calibrate ourmore » In Salah model, which includes a fracture zone perpendicular to the well, obtaining a good fitting with the injection pressure measured at KB-502 and the rapid CO 2 breakthrough that occurred at the observation well KB-5 located 2 km away from the injection well. CO 2 preferentially advances through the fracture zone, which becomes two orders of magnitude more permeable than the rest of the reservoir. Nevertheless, the effect of cooling on the long-term injectivity enhancement is limited in pressure dominated storage sites, like at In Salah, because most of the permeability enhancement is due to overpressure. But, thermal effects enhance injectivity in cooling dominated storage sites, which may decrease the injection pressure by 20%, saving a significant amount of compression energy all over the duration of storage projects. Overall, our simulation results show that cooling has the potential to enhance injectivity in fractured reservoirs.« less

A Raman and Infrared Spectroscopic Study of Anglesite at High Pressures

NASA Astrophysics Data System (ADS)

Sawchuk, K. L. S.; Vennari, C.; O'Bannon, E. F., III; Williams, Q.

2016-12-01

Raman and infrared spectra of the barite-structured lead sulfate, anglesite (PbSO4), were collected to 40 GPa and 300 K. Our particular interest in this compound is oriented towards determining what post-barite structures sulfates in the deep earth sulfur cycle might ultimately convert to at high pressures. Additionally, the study of ABX4 materials has applications to materials science that include their usage as scintillation detectors, and PbSO4 has been demonstrated to have non-linear optical properties. Measurements were made of the internal modes of the SO4 group that lie between 400 and 1200 cm-1 and lattice vibrations that occur between 50 and 250 cm-1. In accord with previous Raman work of Lee et al. (WJCMP, 2012), two phase transitions initiate at 13 and 23 GPa which are reversible on decompression. The 13 GPa transition is subtle and involves splitting of a few modes, particularly the SO4 tetragonal stretching and bending-derived Raman and associated infrared modes. This transition likely goes to a structure with a greater degree of Davydov splitting between corresponding Raman- and infrared-active vibrations, which may indicate a greater distortion of the SO4 tetrahedra. The transition at 23 GPa is a major, sluggish, transition that causes splitting and/or shifting in all observed Raman and infrared modes. These new peaks are lower in frequency and become the sole spectral features by 42 GPa suggesting a higher symmetry structure than previously inferred. It appears that this transition involves a coexistence of phases until the transition is ultimately complete around 42 GPa. Based on the structural systematics of ABX4 phases and factor group analysis, it is likely the structure goes to the monazite structure at high pressures, but that this transition required marked overpressurization to occur at 300K. The accessing of this monazite-like phase is in general accord with systematics of high-pressure transitions in ABX4 phases, and indicates that monazite-structured polymorphs may be anticipated within subducted high-pressure sulfates within Earth's mantle.

30 CFR 250.1000 - General requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE... shall be designed, installed, operated, maintained, and abandoned to provide safe and pollution-free..., over-pressure protection devices, cathodic protection equipment, and pigging devices, etc.) that serve...

75 FR 17786 - Advisory Committee on Reactor Safeguards; Meeting of the ACRS Subcommittee on Power Uprates...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

... Boiling Water Reactor Owners Group's (BWROG) topical report NEDC-33347P, ``Containment Overpressure Credit... for the Use of Containment Accident Pressure in Determining the NPSH Margin of ECCS and Containment...

Pressure Wave Propagation along the Décollement of the Nankai Accretionary Wedge: Implications for Aseismic Slip Events

NASA Astrophysics Data System (ADS)

Joshi, A.; Appold, M. S.

2015-12-01

Seismic and hydrologic observations of the Nankai subduction zone made by the Ocean Drilling Program suggest that pore fluid pressures within the accretionary wedge décollement are highly overpressured to near lithostatic values below depths of 2 km beneath the sea floor as a result of sediment diagenesis and dehydration of the subducting oceanic plate. This overpressured zone is also observed to discharge pulses of high fluid pressure that migrate up-dip along the décollement at rates of 1's of km/day. These high pressure pulses along the décollement may cause large enough reductions in the local effective stress to account for aseismic slip events that have been found to propagate also at rates of 1's of km/day. Because elevated fluid pressure and correspondingly decreased effective stress can lead to a dilation of porosity, the pressure waves may become effective agents of fluid transport that can travel more quickly than fluids flowing in the background Darcian flow regime. The purpose of the present study was to seek theoretical confirmation that pressure waves are able to travel quickly enough to account for the seismic and hydrological observations documented. This confirmation was sought through a transient one-dimensional numerical solution to the differential fluid mass conservation equation for an elastic porous medium. Results of the numerical simulations show that when overpressures at depths greater than 2 km in the décollement exceed lithostatic pressure by at least 3%, pressure waves are formed that migrate up-dip at rates fast enough to account for aseismic slip over a broad range of geologic conditions. Pressure waves spawned from these depths in the décollement may travel fast enough to account for aseismic slip when overpressures there are as low as 99% of lithostatic pressure, but require low specific storage of 3×10-6 m-1, high sensitivity of permeability to effective stress, low permeability no higher than about 10-21 m2 at depths below 2 km in the décollement, and an accurate accounting of the decrease in fluid viscosity with increasing depth. Thus, pressure waves could account for aseismic slip in the Nankai accretionary wedge if conditions were near the limits of geologically reasonable ranges.

Sonic Booms And Building Vibration Revisited

NASA Astrophysics Data System (ADS)

Sutherland, Louis C.; Kryter, Karl D.; Czech, Joseph

2006-05-01

Lessons learned from the 1960's sonic boom tests at St. Louis, Oklahoma City and at Edwards Air Force Base (EAFB) and more recently in communities near EAFB and Nellis AFB are briefly reviewed from the standpoint of building vibration and rattle response induced by the sonic boom signature. Available data on the vibro-acoustic threshold of rattle are considered along with the principal sonic boom signature parameters, peak overpressure and duration, which drive the low frequency vibration response of buildings to sonic booms. Implications for the current effort to develop an acceptable sonic boom signature are considered with this overview of current understanding of building vibration response to sonic booms. Possible gaps in this current knowledge for current technology boom signatures are considered.

Sonic-boom ground-pressure measurements from Apollo 15

NASA Technical Reports Server (NTRS)

Hilton, D. A.; Henderson, H. R.; Mckinney, R.

1972-01-01

Sonic boom pressure signatures recorded during the launch and reentry phases of the Apollo 15 mission are presented. The measurements were obtained along the vehicle ground track at 87 km and 970 km downrange from the launch site during ascent; and at 500 km, 55.6 km, and 12.9 km from the splashdown point during reentry. Tracings of the measured signatures are included along with values of the overpressure, impulse, time duration, and rise times. Also included are brief descriptions of the launch and recovery test areas in which the measurements were obtained, the sonic boom instrumentation deployment, flight profiles and operating conditions for the launch vehicle and spacecraft, surface weather information at the measuring sites, and high altitude weather information for the general measurement areas.

On the violence of thermal explosion in solid explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidester, S.K.; Tarver, C.M.; Green, L.G.

Heavily confined cylinders of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and triaminotrinitrobenzene (TATB) were heated at rates varying from 2 C/min to 3.3 C/h. Fourteen of the cylinders were hollow, and inner metallic liners with small heaters attached were used to produce uniform temperatures just prior to explosion. A complex thermocouple pattern was used to measure the temperature history throughout the charge and to determine the approximate location where the runaway exothermic reaction first occurred. The violence of the resulting explosion was measured using velocity pin arrays placed inside and outside of the metal confinement cylinders, flash x-rays, overpressure gauges, and fragment collection techniques.more » Five cylinders were intentionally detonated for violence comparisons. The measured temperature histories, times to explosion, and the locations of first reaction agreed closely with those calculated by a two-dimensional heat transfer code using multistep chemical decomposition models. The acceleration of the confining metal cylinders by the explosion process was accurately simulated using a two-dimensional pressure dependent deflagration reactive flow hydrodynamic mode. The most violent HMX thermal explosions gradually accelerated their outer cases to velocities approaching those of intentional detonations approximately 120 {micro}m after the onset of explosion. The measured inner cylinder collapse velocities from thermal explosions were considerably lower than those produced by detonations. In contrast to the HMX thermal reactions, no violent thermal explosions were produced by the TATB-based explosive LX-17. A heavily confined, slowly heated LX-17 test produced sufficient pressure to cause a 0.1 cm bend in a 2 cm thick steel plate.« less

Structural integrity of a confinement vessel for testing nuclear fuels for space propulsion

NASA Astrophysics Data System (ADS)

Bergmann, V. L.

Nuclear propulsion systems for rockets could significantly reduce the travel time to distant destinations in space. However, long before such a concept can become reality, a significant effort must be invested in analysis and ground testing to guide the development of nuclear fuels. Any testing in support of development of nuclear fuels for space propulsion must be safely contained to prevent the release of radioactive materials. This paper describes analyses performed to assess the structural integrity of a test confinement vessel. The confinement structure, a stainless steel pressure vessel with bolted flanges, was designed for operating static pressures in accordance with the ASME Boiler and Pressure Vessel Code. In addition to the static operating pressures, the confinement barrier must withstand static overpressures from off-normal conditions without releasing radioactive material. Results from axisymmetric finite element analyses are used to evaluate the response of the confinement structure under design and accident conditions. For the static design conditions, the stresses computed from the ASME code are compared with the stresses computed by the finite element method.

Earthquake induced variations in extrusion rate: A numerical modeling approach to the 2006 eruption of Merapi Volcano (Indonesia)

NASA Astrophysics Data System (ADS)

Carr, Brett B.; Clarke, Amanda B.; de'Michieli Vitturi, Mattia

2018-01-01

Extrusion rates during lava dome-building eruptions are variable and eruption sequences at these volcanoes generally have multiple phases. Merapi Volcano, Java, Indonesia, exemplifies this common style of activity. Merapi is one of Indonesia's most active volcanoes and during the 20th and early 21st centuries effusive activity has been characterized by long periods of very slow (<0.1 m3 s-1) extrusion rate interrupted every few years by short episodes of elevated extrusion rates (1-4 m3 s-1) lasting weeks to months. One such event occurred in May-July 2006, and previous research has identified multiple phases with different extrusion rates and styles of activity. Using input values established in the literature, we apply a 1D, isothermal, steady-state numerical model of magma ascent in a volcanic conduit to explain the variations and gain insight into corresponding conduit processes. The peak phase of the 2006 eruption occurred in the two weeks following the May 27 Mw 6.4 earthquake 50 km to the south. Previous work has suggested that the peak extrusion rates observed in early June were triggered by the earthquake through either dynamic stress-induced overpressure or the addition of CO2 due to decarbonation and gas escape from new fractures in the bedrock. We use the numerical model to test the feasibility of these proposed hypotheses and show that, in order to explain the observed change in extrusion rate, an increase of approximately 5-7 MPa in magma storage zone overpressure is required. We also find that the addition of ∼1000 ppm CO2 to some portion of the magma in the storage zone following the earthquake reduces water solubility such that gas exsolution is sufficient to generate the required overpressure. Thus, the proposed mechanism of CO2 addition is a viable explanation for the peak phase of the Merapi 2006 eruption. A time-series of extrusion rate shows a sudden increase three days following the earthquake. We explain this three-day delay by the combined time required for the effects of the earthquake and corresponding CO2 increase to develop in the magma storage system (1-2 days), and the time we calculate for the affected magma to ascend from storage zone to surface (40 h). The increased extrusion rate was sustained for 2-7 days before dissipating and returning to pre-earthquake levels. During this phase, we estimate that 3.5 million m3 DRE of magma was erupted along with 11 ktons of CO2. The final phase of the 2006 eruption was characterized by highly variable extrusion rates. We demonstrate that those changes were likely controlled by failure of the edifice that had been confining the dome to Merapi's crater and subsequent large dome collapses. The corresponding reductions in confining pressure caused increased extrusion rates that rapidly rebuilt the dome and led to further collapses, a feedback cycle that prolonged the eruption. In a more general sense, this study demonstrates that both internal changes, such as magma volatile content and overpressure, and external forces, such as edifice collapse and regional earthquakes, can affect variations in eruption intensity. Further, we also demonstrate how these external forces can initiate internal changes and how these parameters may interact with one another in a feedback scenario.

Aerofractures in Confined Granular Media

NASA Astrophysics Data System (ADS)

Eriksen, Fredrik K.; Turkaya, Semih; Toussaint, Renaud; Måløy, Knut J.; Flekkøy, Eirik G.

2015-04-01

We will present the optical analysis of experimental aerofractures in confined granular media. The study of this generic process may have applications in industries involving hydraulic fracturing of tight rocks, safe construction of dams, tunnels and mines, and in earth science where phenomena such as mud volcanoes and sand injectites are results of subsurface sediment displacements driven by fluid overpressure. It is also interesting to increase the understanding the flow instability itself, and how the fluid flow impacts the solid surrounding fractures and in the rest of the sample. Such processes where previously studied numerically [Niebling 2012a, Niebling 2012b] or in circular geometries. We will here explore experimentally linear geometries. We study the fracturing patterns that form when air flows into a dense, non-cohesive porous medium confined in a Hele-Shaw cell - i.e. into a packing of dry 80 micron beads placed between two glass plates separated by ~1mm. The cell is rectangular and fitted with a semi-permeable boundary to the atmosphere - blocking beads but not air - on one short edge, while the other three edges are impermeable. The porous medium is packed inside the cell between the semi-permeable boundary and an empty volume at the sealed side where the air pressure can be set and kept at a constant overpressure (1-2bar). Thus, for the air trapped inside the cell to release the overpressure it has to move through the solid. At high enough overpressures the air flow deforms the solid and increase permeability in some regions along the air-solid interface, which results in unstable flow and aerofracturing. Aerofractures are thought to be an analogue to hydrofractures, and an advantage of performing aerofracturing experiments in a Hele-Shaw cell is that the fracturing process can easily be observed in the lab. Our experiments are recorded with a high speed camera with a framerate of 1000 frames per second. In the analysis, by using various image processing techniques, we segment out and study the aerofractures over time looking at growth dynamics, fractal dimension and characteristics such as average finger thickness as function of depth into the solid. Also, by performing image correlation on two subsequent frames we estimate displacement fields and investigate the surrounding stress and strain fields in the solid around the fractures. Several experiments are performed with various overpressures and packing densities, and we compare the results. In a directly related project, acoustic emissions are recorded on a cell plate during experiments, and one of our goals is to correlate acoustic events and observations. We will also compare the dependence of the patterns on the saturation of the initial deformable porous material, by comparing experiments performed by air injection in air saturated granular media, to some in liquid saturated granular media. References: MJ Niebling, R Toussaint, EG Flekkøy, KJ Måløy, 2012, Dynamic aerofracture of dense granular packings, 2012, Physical Review E 86 (6), 061315 M Niebling, R Toussaint, EG Flekkøy, KJ Måløy, 2012, Numerical studies of aerofractures in porous media, Revista Cubana de Fisica 29 (1E), pp. 1E66-1E70

75 FR 21046 - Advisory Committee on Reactor Safeguards

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-22

... NUCLEAR REGULATORY COMMISSION Advisory Committee on Reactor Safeguards In accordance with the... on Reactor Safeguards (ACRS) will hold a meeting on May 6-8, 2010, 11545 Rockville Pike, Rockville....: Boiling Water Reactor (BWR) Owners Group (BWROG) Topical Report NEDC-33347P, ``Containment Overpressure...

40 CFR 68.28 - Alternative release scenario analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... overfilling and spill, or overpressurization and venting through relief valves or rupture disks; and (v... Consequence Analysis Guidance or any commercially or publicly available air dispersion modeling techniques, provided the techniques account for the specified modeling conditions and are recognized by industry as...

Blast Overpressure Studies.

DTIC Science & Technology

1998-05-01

Ribera U.S. Army Aeromedical Research Laboratory (205) 255-6913 By signing this form I hereby acknowledge I have fully read and understand the...Army Aeromedical Research Laboratory (334) 255-6821 MAJ John Ribera U.S. Army Aeromedical Research Laboratory (334) 255-6823 By signing this form I

Development of Overpressures at Nankai Accretionary Prism, Ocean Drilling Program Sites 1173 and 1174

NASA Astrophysics Data System (ADS)

Gamage, K.; Screaton, E.

2003-12-01

In this study, we used a one-dimensional model of sedimentation, initial prism loading, and fluid flow to examine the development of overpressures at the toe of the Nankai accretionary complex. A permeability-porosity relationship was established for hemipelagic sediments from laboratory measured permeabilities as an input to the model. Vertical permeabilities were measured for 10 core samples from the Ocean Drilling Program (ODP) Leg 190, Sites 1173 and 1174, from the upper and lower Shikoku Basin facies. Both sites were drilled along the Muroto Transect through the dècollement zone or its equivalent. Site 1173 is located 11 km seaward of the deformation front and it represents the undeformed incoming sediments, where as Site 1174 represents sediments within the proto-thrust zone. Although turbidite-rich sediments dominate the Nankai accretionary prism, the dècollement and underthrust sediments are primarily composed of hemipelagic muds. Using the permeability-porosity relationship, our modeling results indicate excess pore pressures that are greater than 30% of lithostatic pressure at the toe of the prism at a convergence rate of 4cm/yr. These values are slightly lower than previously inferred excess pore pressures estimated from porosity data. Additional runs were conducted to simulate a 10-m thick low permeability barrier at the dècollement where vertical fluid flow is restricted. The low permeability barrier required a permeability less than 1 x 10-19 m2 to generate excess pore pressures greater than 50% of lithostatic pressure. Modeling was further extended to test the significance of variable prism loading rates due to uncertainties in the convergence rate and affects of lateral stress above the dècollement.

A Novel Closed-Head Model of Mild Traumatic Brain Injury Using Focal Primary Overpressure Blast to the Cranium in Mice

PubMed Central

Guley, Natalie H.; Rogers, Joshua T.; Del Mar, Nobel A.; Deng, Yunping; Islam, Rafiqul M.; D'Surney, Lauren; Ferrell, Jessica; Deng, Bowei; Hines-Beard, Jessica; Bu, Wei; Ren, Huiling; Elberger, Andrea J.; Marchetta, Jeffrey G.; Rex, Tonia S.; Honig, Marcia G.

2016-01-01

Abstract Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25–40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50–60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits. PMID:26414413

Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

DOE Data Explorer

Buscheck, Thomas A.

2012-01-01

Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk: FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. Based on a range of well schemes, techno-economic analyses of the levelized cost of electricity (LCOE) are conducted to determine the economic benefits of integrating GCS with geothermal energy production. In addition to considering CO2 injection, reservoir analyses are conducted for nitrogen (N2) injection to investigate the potential benefits of incorporating N2 injection with integrated geothermal-GCS, as well as the use of N2 injection as a potential pressure-support and working-fluid option. Phase 1 includes preliminary environmental risk assessments of integrated geothermal-GCS, with the focus on managing reservoir overpressure. Phase 1 also includes an economic survey of pipeline costs, which will be applied in Phase 2 to the analysis of CO2 conveyance costs for techno-economics analyses of integrated geothermal-GCS reservoir sites. Phase 1 also includes a geospatial GIS survey of potential integrated geothermal-GCS reservoir sites, which will be used in Phase 2 to conduct sweet-spot analyses that determine where promising geothermal resources are co-located in sedimentary settings conducive to safe CO2 storage, as well as being in adequate proximity to large stationary CO2 sources.

Sediment compaction in deepwater basin of the South China Sea: estimation from ODP 184 and IODP 349 drilling well data.

NASA Astrophysics Data System (ADS)

Tuoyu, W.; Xie, Y.

2017-12-01

Abnormal compaction in deepwater basins not only cause serious soft sediment deformation, but also significantly affect the safety of the drilling campaign. Therefore, study the compaction condition in the sediments would be an important task in the deepwater basin and associate with the environment variation. We analyze the drilling data from the ODP Leg 184 Site 1144, 1146, 1148 and the IODP Leg 349 Site U1431, U1432, U1433, U1435 to study the sediment compaction and controls in the northern South China Sea. We have found the sedimentation rate, sediment content, distribution area and buried depth control the sediment compaction in deepwater basin of the South China Sea. Among all the factors, the sediment content is the most important factor. The fitted normal compacted coefficients and the mudline porosity for interval 50 m shows disciplinary variation versus depth. The pore pressure predicted from different fitted results shows different overpressure situation. The normal compaction trend from Site 1144 reflects the porosity variation trend in stable deposition basins in the northern South China Sea. The predicted pore pressure shows overpressure at Site 1144, which is attributed to compaction disequilibrium. Nevertheless, the mixed lithology column may influence the predicted overpressure at Site 1148, which is responsible for the confusing result. Above all. we find that sediment compaction should be act as a proxy for pore pressure in the deepwater basin of the South China Sea. The study will help us to nature of sedimentation in the deepwater basin set up and can be used as analog for older sediments deposited in the similar kind of depositional environment in deepwater basin of the South China Sea.

Pressure evolution and deformation of confined granular media during pneumatic fracturing

NASA Astrophysics Data System (ADS)

Eriksen, Fredrik K.; Toussaint, Renaud; Turquet, Antoine Léo; Mâløy, Knut J.; Flekkøy, Eirik G.

2018-01-01

By means of digital image correlation, we experimentally characterize the deformation of a dry granular medium confined inside a Hele-Shaw cell due to air injection at a constant overpressure high enough to deform it (from 50 to 250 kPa). Air injection at these overpressures leads to the formation of so-called pneumatic fractures, i.e., channels empty of beads, and we discuss the typical deformations of the medium surrounding these structures. In addition we simulate the diffusion of the fluid overpressure into the medium, comparing it with the Laplacian solution over time and relating pressure gradients with corresponding granular displacements. In the compacting medium we show that the diffusing pressure field becomes similar to the Laplace solution on the order of a characteristic time given by the properties of the pore fluid, the granular medium, and the system size. However, before the diffusing pressure approaches the Laplace solution on the system scale, we find that it resembles the Laplacian field near the channels, with the highest pressure gradients on the most advanced channel tips and a screened pressure gradient behind them. We show that the granular displacements more or less always move in the direction against the local pressure gradients, and when comparing granular velocities with pressure gradients in the zone ahead of channels, we observe a Bingham type of rheology for the granular paste (the mix of air and beads), with an effective viscosity μB and displacement thresholds ∇ ⃗Pc evolving during mobilization and compaction of the medium. Such a rheology, with disorder in the displacement thresholds, could be responsible for placing the pattern growth at moderate injection pressures in a universality class like the dielectric breakdown model with η =2 , where fractal dimensions are found between 1.5 and 1.6 for the patterns.

Overpressure and hydrocarbon accumulations in Tertiary strata, Gulf Coast of Louisiana

USGS Publications Warehouse

Nelson, Philip H.

2012-01-01

Many oil and gas reservoirs in Tertiary strata of southern Louisiana are located close to the interface between a sand-rich, normally pressured sequence and an underlying sand-poor, overpressured sequence. This association, recognized for many years by Gulf Coast explorationists, is revisited here because of its relevance to an assessment of undiscovered oil and gas potential in the Gulf Coast of Louisiana. The transition from normally pressured to highly overpressured sediments is documented by converting mud weights to pressure, plotting all pressure data from an individual field as a function of depth, and selecting a top and base of the pressure transition zone. Vertical extents of pressure transition zones in 34 fields across southern onshore Louisiana range from 300 to 9000 ft and are greatest in younger strata and in the larger fields. Display of pressure transition zones on geologic cross sections illustrates the relative independence of the depth of the pressure transition zone and geologic age. Comparison of the depth distribution of pressure transition zones with production intervals confirms previous findings that production intervals generally overlap the pressure transition zone in depth and that the median production depth lies above the base of the pressure transition zone in most fields. However, in 11 of 55 fields with deep drilling, substantial amounts of oil and gas have been produced from depths deeper than 2000 ft below the base of the pressure transition zone. Mud-weight data in 7 fields show that "local" pressure gradients range from 0.91 to 1.26 psi/ft below the base of the pressure transition zone. Pressure gradients are higher and computed effective stress gradients are negative in younger strata in coastal areas, indicating that a greater potential for fluid and sediment movement exists there than in older Tertiary strata.

Role of H2O in Generating Subduction Zone Earthquakes

NASA Astrophysics Data System (ADS)

Hasegawa, A.

2017-03-01

A dense nationwide seismic network and high seismic activity in Japan have provided a large volume of high-quality data, enabling high-resolution imaging of the seismic structures defining the Japanese subduction zones. Here, the role of H2O in generating earthquakes in subduction zones is discussed based mainly on recent seismic studies in Japan using these high-quality data. Locations of intermediate-depth intraslab earthquakes and seismic velocity and attenuation structures within the subducted slab provide evidence that strongly supports intermediate-depth intraslab earthquakes, although the details leading to the earthquake rupture are still poorly understood. Coseismic rotations of the principal stress axes observed after great megathrust earthquakes demonstrate that the plate interface is very weak, which is probably caused by overpressured fluids. Detailed tomographic imaging of the seismic velocity structure in and around plate boundary zones suggests that interplate coupling is affected by local fluid overpressure. Seismic tomography studies also show the presence of inclined sheet-like seismic low-velocity, high-attenuation zones in the mantle wedge. These may correspond to the upwelling flow portion of subduction-induced secondary convection in the mantle wedge. The upwelling flows reach the arc Moho directly beneath the volcanic areas, suggesting a direct relationship. H2O originally liberated from the subducted slab is transported by this upwelling flow to the arc crust. The H2O that reaches the crust is overpressured above hydrostatic values, weakening the surrounding crustal rocks and decreasing the shear strength of faults, thereby inducing shallow inland earthquakes. These observations suggest that H2O expelled from the subducting slab plays an important role in generating subduction zone earthquakes both within the subduction zone itself and within the magmatic arc occupying its hanging wall.

Neuronal DNA Methylation Profiling of Blast-Related Traumatic Brain Injury.

PubMed

Haghighi, Fatemeh; Ge, Yongchao; Chen, Sean; Xin, Yurong; Umali, Michelle U; De Gasperi, Rita; Gama Sosa, Miguel A; Ahlers, Stephen T; Elder, Gregory A

2015-08-15

Long-term molecular changes in the brain resulting from blast exposure may be mediated by epigenetic changes, such as deoxyribonucleic acid (DNA) methylation, that regulate gene expression. Aberrant regulation of gene expression is associated with behavioral abnormalities, where DNA methylation bridges environmental signals to sustained changes in gene expression. We assessed DNA methylation changes in the brains of rats exposed to three 74.5 kPa blast overpressure events, conditions that have been associated with long-term anxiogenic manifestations weeks or months following the initial exposures. Rat frontal cortex eight months post-exposure was used for cell sorting of whole brain tissue into neurons and glia. We interrogated DNA methylation profiles in these cells using Expanded Reduced Representation Bisulfite Sequencing. We obtained data for millions of cytosines, showing distinct methylation profiles for neurons and glia and an increase in global methylation in neuronal versus glial cells (p<10(-7)). We detected DNA methylation perturbations in blast overpressure-exposed animals, compared with sham blast controls, within 458 and 379 genes in neurons and glia, respectively. Differentially methylated neuronal genes showed enrichment in cell death and survival and nervous system development and function, including genes involved in transforming growth factor β and nitric oxide signaling. Functional validation via gene expression analysis of 30 differentially methylated neuronal and glial genes showed a 1.2 fold change in gene expression of the serotonin N-acetyltransferase gene (Aanat) in blast animals (p<0.05). These data provide the first genome-based evidence for changes in DNA methylation induced in response to multiple blast overpressure exposures. In particular, increased methylation and decreased gene expression were observed in the Aanat gene, which is involved in converting serotonin to the circadian hormone melatonin and is implicated in sleep disturbance and depression associated with traumatic brain injury.

Experimental study of a valveless pulse detonation rocket engine using nontoxic hypergolic propellants

NASA Astrophysics Data System (ADS)

Kan, Brandon K.

A pulsed detonation rocket engine concept was explored through the use of hypergolic propellants in a fuel-centered pintle injector combustor. The combustor design yielded a simple open ended chamber with a pintle type injection element and pressure instrumentation. High-frequency pressure measurements from the first test series showed the presence of large pressure oscillations in excess of 2000 psia at frequencies between 400-600 hz during operation. High-speed video confirmed the high-frequency pulsed behavior and large amounts of after burning. Damaged hardware and instrumentation failure limited the amount of data gathered in the first test series, but the experiments met original test objectives of producing large over-pressures in an open chamber. A second test series proceeded by replacing hardware and instrumentation, and new data showed that pulsed events produced under expanded exhaust prior to pulsing, peak pressures around 8000 psi, and operating frequencies between 400-800 hz. Later hot-fires produced no pulsed behavior despite undamaged hardware. The research succeeded in producing pulsed combustion behavior using hypergolic fuels in a pintle injector setup and provided insights into design concepts that would assist future injector designs and experimental test setups.

Overview of the Ares I Scale Model Acoustic Test Program

NASA Technical Reports Server (NTRS)

Counter, Douglas D.; Houston, Janice D.

2011-01-01

Launch environments, such as lift-off acoustic (LOA) and ignition overpressure (IOP), are important design factors for any vehicle and are dependent upon the design of both the vehicle and the ground systems. LOA environments are used directly in the development of vehicle vibro-acoustic environments and IOP is used in the loads assessment. The NASA Constellation Program had several risks to the development of the Ares I vehicle linked to LOA. The risks included cost, schedule and technical impacts for component qualification due to high predicted vibro-acoustic environments. One solution is to mitigate the environment at the component level. However, where the environment is too severe for component survivability, reduction of the environment itself is required. The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the Ares I LOA and IOP environments for the vehicle and ground systems including the Mobile Launcher (ML) and tower. An additional objective was to determine the acoustic reduction for the LOA environment with an above deck water sound suppression system. ASMAT was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116 (TS 116). The ASMAT program is described in this presentation.

The effects of simulated sonic booms on tracking performance and autonomic response.

DOT National Transportation Integrated Search

1971-06-01

Subjects were exposed to four simulated 'indoor' sonic booms over an approximate thirty-minute period. The overpressure levels were 1.0, 2.0 and 4.0 psf (as measured 'outdoors') with durations of 295 milliseconds. Subjects performed a two-dimensional...

49 CFR 195.262 - Pumping equipment.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Pumping equipment. 195.262 Section 195.262... PIPELINE Construction § 195.262 Pumping equipment. (a) Adequate ventilation must be provided in pump... provided in each pump station: (1) Safety devices that prevent overpressuring of pumping equipment...

30 CFR 7.502 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the combined effects of air movement, heat, and humidity on the human body. Breathable oxygen. Oxygen.... Noncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Overpressure. The highest pressure over the...

30 CFR 7.502 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the combined effects of air movement, heat, and humidity on the human body. Breathable oxygen. Oxygen.... Noncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Overpressure. The highest pressure over the...

30 CFR 7.502 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the combined effects of air movement, heat, and humidity on the human body. Breathable oxygen. Oxygen.... Noncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Overpressure. The highest pressure over the...

30 CFR 7.502 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the combined effects of air movement, heat, and humidity on the human body. Breathable oxygen. Oxygen.... Noncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Overpressure. The highest pressure over the...

30 CFR 7.502 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the combined effects of air movement, heat, and humidity on the human body. Breathable oxygen. Oxygen.... Noncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Overpressure. The highest pressure over the...

Incorporation of zinc in MOCVD growth of Ga 0.5In 0.5P

NASA Astrophysics Data System (ADS)

Kurtz, Sarah R.; Olson, J. M.; Kibbler, A. E.; Bertness, K. A.

1992-11-01

Data are presented for the Zn doping of Ga 0.5In 0.5P, showing that the hole and zinc concentrations increase almost linearly with zinc flow, and also increase with the V/III ratio and with growth rate at a fixed V/III ratio. These observations are consistent with other reports that show the incorporation of zinc to increase with V/III ratio for both GaAs and Ga 0.5In 0.5P deposition by metalorganic chemical vapor deposition (MOCVD). The growth-rate dependence of the zinc incorporation in Ga 0.5In 0.5P has not previously been reported. A model based on varying group V coverage of the step where zinc is most strongly bound is presented and compared with the data. The model predicts that the zinc incorporation increases with increasing phosphorus overpressure, but should be independent of group III overpressure in the parameter space investigated here.

Frictional strength of wet and dry montmorillonite

USGS Publications Warehouse

Morrow, Carolyn A.; Moore, Diane E.; Lockner, David A.

2017-01-01

Montmorillonite is a common mineral in fault zones, and its low strength relative to other common gouge minerals is important in many models of fault rheology. However, the coefficient of friction, μ, varies with degree of saturation and is not well constrained in the literature due to the difficulty of establishing fully drained or fully dried states in the laboratory. We measured μ of both saturated and oven-dried montmorillonite at normal stresses up to 700 MPa. Care was taken to shear saturated samples slowly enough to avoid pore fluid overpressure. For saturated samples, μ increased from 0.10 to 0.28 with applied effective normal stress, while for dry samples μ decreased from 0.78 to 0.45. The steady state rate dependence of friction, (a − b), was positive, promoting stable sliding. The wide disparity in reported frictional strengths can be attributed to experimental procedures that promote differing degrees of partial saturation or overpressured pore fluid conditions.

Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

DOE Data Explorer

Buscheck, Thomas A.

2012-01-01

Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk : FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. This submittal contains input and output files of the reservoir model analyses. A reservoir-model "index-html" file was sent in a previous submittal to organize the reservoir-model input and output files according to sections of the FY1 Final Report to which they pertain. The recipient should save the file: Reservoir-models-inputs-outputs-index.html in the same directory that the files: Section2.1.*.tar.gz files are saved in.

Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

DOE Data Explorer

Buscheck, Thomas A.

2000-01-01

Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk: FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. This submittal contains input and output files of the reservoir model analyses. A reservoir-model "index-html" file was sent in a previous submittal to organize the reservoir-model input and output files according to sections of the FY1 Final Report to which they pertain. The recipient should save the file: Reservoir-models-inputs-outputs-index.html in the same directory that the files: Section2.1.*.tar.gz files are saved in.

Passive blast pressure sensor

DOEpatents

King, Michael J.; Sanchez, Roberto J.; Moss, William C.

2013-03-19

A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

Development and evaluation of a device to simulate a sonic boom

NASA Technical Reports Server (NTRS)

Rash, L. C.; Barrett, R. F.; Hart, F. D.

1972-01-01

A device to simulate the vibrational and acoustical properties of a sonic boom was developed and evaluated. The design employed a moving circular diaphragm which produced pressure variations by altering the volume of an air-tight enclosure that was located adjacent to an acoustical test chamber. A review of construction oriented problems, along with their solutions, is presented. The simulator is shown to produce the effects of sonic booms having pressure signatures with rise times as low as 5 milliseconds, durations as short as 80 milliseconds, and overpressures as high as 2.5 pounds per square foot. Variations in the signatures are possible by independent adjustments of the simulator. The energy spectral density is also shown to be in agreement with theory and with actual measurements for aircraft.

TNT equivalency of M10 propellant

NASA Technical Reports Server (NTRS)

Mcintyre, F. L.; Price, P.

1978-01-01

Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

An Empirical Non-TNT Approach to Launch Vehicle Explosion Modeling

NASA Technical Reports Server (NTRS)

Blackwood, James M.; Skinner, Troy; Richardson, Erin H.; Bangham, Michal E.

2015-01-01

In an effort to increase crew survivability from catastrophic explosions of Launch Vehicles (LV), a study was conducted to determine the best method for predicting LV explosion environments in the near field. After reviewing such methods as TNT equivalence, Vapor Cloud Explosion (VCE) theory, and Computational Fluid Dynamics (CFD), it was determined that the best approach for this study was to assemble all available empirical data from full scale launch vehicle explosion tests and accidents. Approximately 25 accidents or full-scale tests were found that had some amount of measured blast wave, thermal, or fragment explosion environment characteristics. Blast wave overpressure was found to be much lower in the near field than predicted by most TNT equivalence methods. Additionally, fragments tended to be larger, fewer, and slower than expected if the driving force was from a high explosive type event. In light of these discoveries, a simple model for cryogenic rocket explosions is presented. Predictions from this model encompass all known applicable full scale launch vehicle explosion data. Finally, a brief description of on-going analysis and testing to further refine the launch vehicle explosion environment is discussed.

49 CFR 195.262 - Pumping equipment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... PIPELINE Construction § 195.262 Pumping equipment. (a) Adequate ventilation must be provided in pump... provided in each pump station: (1) Safety devices that prevent overpressuring of pumping equipment..., pumping equipment must be installed on property that is under the control of the operator and at least 15...

49 CFR 195.262 - Pumping equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... PIPELINE Construction § 195.262 Pumping equipment. (a) Adequate ventilation must be provided in pump... provided in each pump station: (1) Safety devices that prevent overpressuring of pumping equipment..., pumping equipment must be installed on property that is under the control of the operator and at least 15...

49 CFR 195.262 - Pumping equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PIPELINE Construction § 195.262 Pumping equipment. (a) Adequate ventilation must be provided in pump... provided in each pump station: (1) Safety devices that prevent overpressuring of pumping equipment..., pumping equipment must be installed on property that is under the control of the operator and at least 15...

49 CFR 195.262 - Pumping equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... PIPELINE Construction § 195.262 Pumping equipment. (a) Adequate ventilation must be provided in pump... provided in each pump station: (1) Safety devices that prevent overpressuring of pumping equipment..., pumping equipment must be installed on property that is under the control of the operator and at least 15...

30 CFR 7.505 - Structural components.

Code of Federal Regulations, 2011 CFR

2011-07-01

... designed for multiple uses to accommodate the structure's maximum occupancy. (ii) The airlock shall be configured to accommodate a stretcher without compromising its function. (4) Be designed and made to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to deployment. (5) Be designed...

30 CFR 7.505 - Structural components.

Code of Federal Regulations, 2013 CFR

2013-07-01

... designed for multiple uses to accommodate the structure's maximum occupancy. (ii) The airlock shall be configured to accommodate a stretcher without compromising its function. (4) Be designed and made to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to deployment. (5) Be designed...

30 CFR 7.505 - Structural components.

Code of Federal Regulations, 2014 CFR

2014-07-01

... designed for multiple uses to accommodate the structure's maximum occupancy. (ii) The airlock shall be configured to accommodate a stretcher without compromising its function. (4) Be designed and made to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to deployment. (5) Be designed...

30 CFR 7.505 - Structural components.

Code of Federal Regulations, 2012 CFR

2012-07-01

... designed for multiple uses to accommodate the structure's maximum occupancy. (ii) The airlock shall be configured to accommodate a stretcher without compromising its function. (4) Be designed and made to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to deployment. (5) Be designed...

30 CFR 7.505 - Structural components.

Code of Federal Regulations, 2010 CFR

2010-07-01

... designed for multiple uses to accommodate the structure's maximum occupancy. (ii) The airlock shall be configured to accommodate a stretcher without compromising its function. (4) Be designed and made to withstand 15 pounds per square inch (psi) overpressure for 0.2 seconds prior to deployment. (5) Be designed...

Miocene seismic stratigraphy and structural evolution of the North and South Padre Island and OCS areas, offshore south Texas

NASA Astrophysics Data System (ADS)

Al-Ghamdi, Ali Mohammed

A seismic stratigraphy and structural study was undertaken to explain the Miocene tectonic and sedimentary evolution of the North and South Padre Island and OCS areas (offshore south Texas). Three linear, elongated growth-fault systems, trending northeast-southwest, occurred in this area: Clemente-Tomas, Corsair, and Wanda. The Clemente-Tomas and the Corsair systems were controlled by late Oligocene-early Miocene overpressured shale uplifted by an influx of clastic sediments. Salt withdrawal helped expand the Corsair fault during the late Oligocene-early Miocene, whereas salt withdrawal formed the Wanda fault system. Nine salt structures (eight diapirs and one sheet), active throughout the Miocene, occurred beneath the present-day shelf edge and in the South Padre Island East Addition. Two types of overpressured shale (overpressured shale ridges and overpressured stratified shale) are present. Seven major depocenters: four controlled by fault expansion and sediment influx, and three by sediment influx and salt withdrawal. The depocenters caused by fault expansion propagate to the northeast, whereas those related to salt withdrawal remain in the same location. Sedimentation in the depocenters was active during the early to middle Miocene. Three sediment fairways, entering the study area from the southwest, west, and northwest, appear to connect the sediment depocenters controlled by salt withdrawal and fault expansion. All sediment fairways propagated first to depocenters associated with salt withdrawal and then to upper slope areas. Lower Miocene time-structure maps of the area show ragged structural relief caused by sedimentation and shale and salt uplifts. Using well-log, seismic reflection, and paleontologic data to support the seismic stratigraphy, five cross-sections were constructed. Large-scale sedimentation occurred at the regressive sea level during the Oligocene beneath the present-day shoreline, forcing the uplift of predeposited marine sediments (shale) through differential loading. The Corsair and Clemente-Tomas faults began forming on the eastern flank of the uplifted shale. More regression occurred at sea level in late Oligocene and early Miocene times, causing the depocenter to shift basinward of the Corsair. Range of hydrocarbon maturity lies between 120sp°C and 165sp°C at NP960 (25-27.5 m.y.) and between 130sp°C and 160sp°C at SP1076 (16-17.5 m.y.) isotherms. Total basement subsidence is about 4 km (SP1076) and 3.2 km (NP960), and the crustal stretching factor (ss) is 2.0 at SP1076 and 1.65 at NP960.

Hydrogen disposal investigation for the Space Shuttle launch complex at Vandenberg Air Force Base

NASA Technical Reports Server (NTRS)

Breit, Terry J.; Elliott, George

1987-01-01

The concern of an overpressure condition on the aft end of the Space Shuttle caused by ignition of unburned hydrogen being trapped in the Space Shuttle Main Engine exhaust duct at the Vandenberg AFB launch complex has been investigated for fifteen months. Approximately twenty-five concepts have been reviewed, with four concepts being thoroughly investigated. The four concepts investigated were hydrogen burnoff ignitors (ignitors located throughout the exhaust duct to continuously ignite any unburned hydrogen), jet mixing (utilizing large volumes of high pressure air to ensure complete combustion of the hydrogen), steam inert (utilizing flashing hot water to inert the duct with steam) and open duct concept (design an open duct or above grade J-deflector to avoid trapping hydrogen gas). Extensive studies, analyses and testing were performed at six test sites with technical support from twenty-two major organizations. In December 1986, the Air Force selected the steam inert concept to be utilized at the Vandenberg launch complex and authorized the design effort.

Dynamic loads on human and animal surrogates at different test locations in compressed-gas-driven shock tubes

NASA Astrophysics Data System (ADS)

Alay, E.; Skotak, M.; Misistia, A.; Chandra, N.

2018-01-01

Dynamic loads on specimens in live-fire conditions as well as at different locations within and outside compressed-gas-driven shock tubes are determined by both static and total blast overpressure-time pressure pulses. The biomechanical loading on the specimen is determined by surface pressures that combine the effects of static, dynamic, and reflected pressures and specimen geometry. Surface pressure is both space and time dependent; it varies as a function of size, shape, and external contour of the specimens. In this work, we used two sets of specimens: (1) anthropometric dummy head and (2) a surrogate rodent headform instrumented with pressure sensors and subjected them to blast waves in the interior and at the exit of the shock tube. We demonstrate in this work that while inside the shock tube the biomechanical loading as determined by various pressure measures closely aligns with live-fire data and shock wave theory, significant deviations are found when tests are performed outside.

Quantification of non-ideal explosion violence with a shock tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Scott I; Hill, Larry G

There is significant interest in quantifying the blast violence associated with various nonideal explosions. Such data is essential to evaluate the damage potential of both explosive cookoff and terrorist explosive scenarios. We present a technique designed to measure the source energy associated with a non-ideal, asymmetrical, and three-dimensional explosion. A tube is used to confine and focus energy from a blast event into a one-dimensional, quasi-planar shock front. During propagation along the length of the tube, the wave is allowed to shocksteepen into a more ideal form. Pressure transducers then measure the shock overpressure as a function of the distancemore » from the source. One-dimensional blast scaling theory allows calculation of the source energy from this data. This small-scale test method addresses cost and noise concerns as well as boosting and symmetry issues associated with large-scale, three-dimensional, blast arena tests. Results from both ideal explosives and non-ideal explosives are discussed.« less

Emissions data by category of engines

NASA Technical Reports Server (NTRS)

Barriage, J.; Westfield, W.; Becker, E. E.

1976-01-01

Exhaust gas pollutant emissions data under test stand conditions were obtained for the following: (1) full-rich baseline test (7-mode cycle), (2) lean-out tests for each power mode, and (3) different spark settings. The test data were also used to create a theoretical 5-mode cycle baseline. The emissions data in the framework of the theoretical 5-mode cycle were emphasized. There is no significant difference in the test results produced by data exhibited on the 7-mode cycle or 5-mode cycle. The 5-mode cycle was slightly more conservative for the carbon monoxide pollutant than the 7-mode cycle. The data were evaluated to determine which mode(s) had the greatest influence on improving general aviation piston engine emissions. Improvements that were achieved as a result of making lean-out adjustments to the fuel metering device were: (1) taxi mode only, (2) taxi and approach modes combined, and (3) leaning-out of the climb mode to best power.

Mixed-Mode Bending Method for Delamination Testing

NASA Technical Reports Server (NTRS)

Reeder, James R.; Crews, John R., Jr.

1990-01-01

A mixed mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end-notch fixture (ENF) mode II loading on a split unidirectional laminate. By loading with a lever, a single applied load simultaneously produces mode I and mode II bending loads on the specimen. This mixed-mode bending (MMB) test was analyzed using both finite-element procedures and beam theory to calculate the mode I and mode II components of strain-energy release rate G(sub I) and G(sub II), respectively. A wide range of G(sub I)/G(sub II) ratios can be produced by varying the load position on the lever. As the delamination extended, the G(sub I)/G(sub II) ratios varied by less than 5%. Beam theory equations agreed closely with the finite-element results and provide a basis for selection of G(sub I)/G(sub II) test ratios and a basis for computing the mode I and mode II components of measured delamination toughness. The MMB test was demonstrated using AS4/PEEK (APC2) unidirectional laminates. The MMB test introduced in this paper is rather simple and is believed to offer several advantages over most current mixed-mode test.

Hydrogen generation by metal corrosion in simulated Waste Isolation Pilot Plant environments. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Telander, M.R.; Westerman, R.E.

1997-03-01

The corrosion and gas-generation characteristics of four material types: low-carbon steel (the current waste packaging material for the Waste Isolation Pilot Plant), Cu-base and Ti-base (alternative packaging) materials, and Al-base (simulated waste) materials were determined in both the liquid and vapor phase of Brine A, a brine representative of an intergranular Salado Formation brine. Test environments consisted primarily of anoxic brine with overpressures of N{sub 2}, CO{sub 2}, H{sub 2}S, and H{sub 2}. Limited tests of low-carbon steel were also performed in simulated-backfill environments and in brine environments with pH values ranging from 3 to 11. Low-carbon steel reacted atmore » a slow, measurable rate with anoxic brine, liberating H{sub 2} on an equimolar basis with Fe reacted. Presence of CO{sub 2} caused the initial reaction to proceed more rapidly, but CO{sub 2}-induced passivation stopped the reaction if the CO{sub 2} were present in sufficient quantities. Addition of H{sub 2}S to a CO{sub 2}-passivated system caused reversal of the passivation. Low-carbon steel immersed in brine with H{sub 2}S showed no reaction, apparently because of passivation of the steel by formation of FeS. Addition of CO{sub 2} to an H{sub 2}S-passivated system did not reverse the passivation. Cu- and Ti-base materials showed essentially no corrosion when exposed to brine and overpressures of N{sub 2}, CO{sub 2}, and H{sub 2}S except for the rapid and complete reaction between Cu-base materials and H{sub 2}S. The Al-base materials reacted at approximately the same rate as low-carbon steel when immersed in anoxic Brine A; considerably more rapidly in the presence of CO{sub 2} or H{sub 2}S; and much more rapidly when iron was present in the system as a brine contaminant. High-purity Al was much more susceptible to corrosion than the 6061 alloy. No significant reaction took place on any material in any environment in the vapor-phase exposures.« less

Causal Analysis For Occurrence Report OR NA-SS-SNL-2000-2015-0005 Unexpected Type of Failure of Thermal Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forbes, Elizabeth H.

2015-08-01

On 6/26/2015 at approximately 1445 in 894/136, a pulse thermal battery (approximately the size of a commercial size C cell) experienced an unexpected failure following an electrical performance test that is routinely conducted on thermal batteries. A dedicated tester for this operation was used and it ran the test until the nominal 28-volt output of the battery had dropped to 5 volts, usually indicative of the battery being spent and safe enough to move. The failure occurred while a test operator was transferring the battery from the testing primary containment box to another primary containment box within the same room;more » initial indications are that the battery experienced an over-pressurization failure which led to the battery's base plate being expelled and the operator receiving a non-recordable injury (bruising to the palm of the hand) from the pressure of the expulsion. The operator was wearing the prescribed PPE (safety glasses and high temperature glove) and was handling the battery appropriately with an open, flat hand. Pictures of the scene are below.« less

Design, Analysis and Testing of a PRSEUS Pressure Cube to Investigate Assembly Joints

NASA Technical Reports Server (NTRS)

Yovanof, Nicolette; Lovejoy, Andrew E.; Baraja, Jaime; Gould, Kevin

2012-01-01

Due to its potential to significantly increase fuel efficiency, the current focus of NASA's Environmentally Responsible Aviation Program is the hybrid wing body (HWB) aircraft. Due to the complex load condition that exists in HWB structure, as compared to traditional aircraft configurations, light-weight, cost-effective and manufacturable structural concepts are required to enable the HWB. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is one such structural concept. A building block approach for technology development of the PRSEUS concept is being conducted. As part of this approach, a PRSEUS pressure cube was developed as a risk reduction test article to examine a new integral cap joint concept. This paper describes the design, analysis and testing of the PRSEUS pressure cube test article. The pressure cube was required to withstand a 2P, 18.4 psi, overpressure load requirement. The pristine pressure cube was tested to 2.2P with no catastrophic failure. After the addition of barely visible impact damage, the cube was pressure loaded to 48 psi where catastrophic failure occurred, meeting the scale-up requirement. Comparison of pretest and posttest analyses with the cube test response agree well, and indicate that current analysis methods can be used to accurately analyze PRSEUS structure for initial failure response.

THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vandersall, K S; Switzer, L L; Garcia, F

2006-06-20

Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the levelmore » of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, C-4 or ANFO explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives. These results will also be compared to that of the Susan Test and reaction thresholds observed in the common small-scale safety tests such as the drop hammer and friction tests in hopes of drawing a correlation.« less

14 CFR 417.218 - Hold-and-resume gate analysis.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Hold-and-resume gate analysis. 417.218 Section 417.218 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... hazardous debris or overpressure to endanger the populated or otherwise protected area. (2) Overflight of an...

14 CFR 417.218 - Hold-and-resume gate analysis.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Hold-and-resume gate analysis. 417.218 Section 417.218 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... hazardous debris or overpressure to endanger the populated or otherwise protected area. (2) Overflight of an...

14 CFR 417.218 - Hold-and-resume gate analysis.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Hold-and-resume gate analysis. 417.218 Section 417.218 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... hazardous debris or overpressure to endanger the populated or otherwise protected area. (2) Overflight of an...

The Overpressured Student

ERIC Educational Resources Information Center

Weissbourd, Richard

2011-01-01

When it comes to academic achievement, many parents in upper- and middle-class communities have gone overboard, hiring tutors for their preschool children and going to enormous lengths to secure a spot for their child in a prestigious college. Even though poor children face many hardships, teenagers in affluent families suffer emotional and moral…

A corporate supersonic transport

NASA Technical Reports Server (NTRS)

Greene, Randall; Seebass, Richard

1996-01-01

This talk address the market and technology for a corporate supersonic transport. It describes a candidate configuration. There seems to be a sufficient market for such an aircraft, even if restricted to supersonic operation over water. The candidate configuration's sonic boom overpressure may be small enough to allow overland operation as well.

14 CFR 417.218 - Hold-and-resume gate analysis.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Hold-and-resume gate analysis. 417.218 Section 417.218 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... hazardous debris or overpressure to endanger the populated or otherwise protected area. (2) Overflight of an...

14 CFR 417.218 - Hold-and-resume gate analysis.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Hold-and-resume gate analysis. 417.218 Section 417.218 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION... hazardous debris or overpressure to endanger the populated or otherwise protected area. (2) Overflight of an...

40 CFR 60.101a - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... system may have an overpressure vent to a flare but the primary purpose for a fuel gas system is to... emissions from sulfur recovery plants by converting these emissions to sulfur dioxide (SO2) and recycling... reduces emissions from sulfur recovery plants by converting these emissions to H2S and either recycling...

40 CFR 60.101a - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... system may have an overpressure vent to a flare but the primary purpose for a fuel gas system is to... emissions from sulfur recovery plants by converting these emissions to sulfur dioxide (SO2) and recycling... reduces emissions from sulfur recovery plants by converting these emissions to H2S and either recycling...

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... API Standard 2510 after October 2, 2000, must have an overfill protection system installed according to section 5.1.2 of API Standard 2510. Other aboveground breakout tanks with 600 gallons (2271 liters... have an overfill protection system installed according to API Recommended Practice 2350. However...

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... API Standard 2510 after October 2, 2000, must have an overfill protection system installed according to section 5.1.2 of API Standard 2510. Other aboveground breakout tanks with 600 gallons (2271 liters... have an overfill protection system installed according to API Recommended Practice 2350. However...

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... API Standard 2510 after October 2, 2000, must have an overfill protection system installed according to section 5.1.2 of API Standard 2510. Other aboveground breakout tanks with 600 gallons (2271 liters... have an overfill protection system installed according to API Recommended Practice 2350. However...

49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... API Standard 2510 after October 2, 2000, must have an overfill protection system installed according to section 5.1.2 of API Standard 2510. Other aboveground breakout tanks with 600 gallons (2271 liters... have an overfill protection system installed according to API Recommended Practice 2350. However...

Signal Processing of Shock-Wave Overpressure Records

DTIC Science & Technology

1981-08-01

SUPERPOSED GAGE-MOUNT RINGING. UNCLASSIFIED FIG. . FORIERSPECRUM O AN - WAV WIT SUPRPSE GAE-OUT RNGNG UNCLASSIFIED SM No. 1021 󈨏- 925 Pa E 0. 00 0"a... midi rfit-valotinrent pmn -ri or grant number oquiprancr mcxlel designation. firnite iamem. militlary project codte irlri ir. I, tir, IlII. 46winl

The multi-modal responses of a physical head model subjected to various blast exposure conditions

NASA Astrophysics Data System (ADS)

Ouellet, S.; Philippens, M.

2018-01-01

The local and global biomechanical response of the body to a blast wave is the first step of a sequence that leads to the development of stresses and strains which can exceed the tolerance of brain tissue. These stresses and strains may then lead to neuro-physical changes in the brain and contribute to initiate a cascade of events leading to injury. The specific biomechanical pathways by which the blast energy is transmitted through the head structure are, however, not clearly understood. Multiple transmission mechanisms have been proposed to explain the generation of brain stresses following the impingement of a blast wave on the head. With the use of a physical head model, the work presented here aims at demonstrating that the proposed transmission mechanisms are not mutually exclusive. They are part of a continuum of head responses where, depending on the exposure conditions, a given mechanism may or may not dominate. This article presents the joint analysis of previous blast test results generated with the brain injury protection evaluation device (BIPED) headform under four significantly different exposure conditions. The focus of the analysis is to demonstrate how the nature of the recorded response is highly dependent on the exposure characteristics and consequently, on the method used to reproduce blast exposure in a laboratory environment. The timing and magnitude of the variations in intra-cranial pressures (ICP) were analysed relative to the external pressure field in order to better understand the wave dynamics occurring within the brain structure of the headform. ICP waveforms were also analysed in terms of their energy spectral density to better identify the energy partitioning between the different modes of response. It is shown that the BIPED response is multi-modal and that the energy partitioning between its different modes of response is greatly influenced by exposure characteristics such as external peak overpressure, impulse, blast wave structure, and direction of propagation. Convincing evidence of stresses generated from local skull deformation is presented along with evidence of stress transmission through relative brain-to-skull motion. These findings suggest that research aimed at defining exposure thresholds should not focus on a single stress transmission mechanism or use experimental designs unrepresentative of realistic blast loading conditions that may favour a given mechanism over another.

Atomic-Scale Structure of the Tin DX Center and Other Related Defects in Aluminum Gallium Arsenide Semiconductors Using Moessbauer Spectroscopy.

NASA Astrophysics Data System (ADS)

Greco, Luigi Alessandro

The DX center in III-V alloys has limited the use of these materials for electronic devices since the defect acts as an electron trap. To be able to control or eliminate the DX center, its atomic scale structure should be understood. Mossbauer spectroscopy has proven to be a valuable technique in probing the atomic-scale structure of certain atomic species. The dopant studied here is ^{119}Sn. The thermal diffusion of Sn in Al_ {rm x}Ga_{rm 1-x }As using different temperatures, times, sample geometries and As_4 overpressures in evacuated and sealed fused silica ampoules was studied by x-ray diffraction (XRD), secondary ion mass spectroscopy and electrochemical capacitance versus voltage measurements. The AlGaAs surfaces decomposed into various Sn, Si, Ga and As oxides when an As_4 overpressure was introduced during annealing. However, annealing under ambient As_4 and furnace cooling eliminated surface decomposition although the Sn diffusion depth was less than that for a 0.5 atm As_4 overpressure. SiO_{rm x} and Si_{rm x }N_{rm y} RF-sputtered thin film capping layers deposited on AlGaAs were studied by XRD and Auger electron spectroscopy. For the annealed SiO_{rm x} films the AlGaAs surface was preserved, independent of the cooling technique used. Mossbauer spectroscopy was conducted on ^{rm 119m} Sn-implanted Al_ {rm x } Ga_{rm 1-x} As (x = 0.22 and 0.25) used for the source experiments and ^{119}Sn-doped Al _{rm x}Ga _{rm 1-x}As (x = 0.15, N _{rm Sn} ~2 times 10 ^{18} cm^{ -3}) for the absorber experiment. The source samples were capped with 120 nm of SiO_ {rm x} to preserve the surface during the systematic study of annealing temperature versus site occupation and electrical activation via Mossbauer spectroscopy at 76 K and 4 K in the dark and in the light (to observe persistent photoconductivity (PPC) due to the DX center). For all of the annealing conditions used the x = 0.22 sample showed little evidence of PPC possibly due to compensating defects and/or radiation-induced capture. After annealing the x = 0.25 sample at 1000^circC for 2 hours under a Ga + Al overpressure, evidence of PPC was found via Hall measurements but no effect was seen by Mossbauer suggesting radiation-induced capture and/or non-nearest-neighbor lattice relaxation. The Ga + Al overpressure also served to decrease the loss of Sn through the SiO _{rm x} film, possibly through the removal of Ga and Al vacancies. The x = 0.15 absorber showed a persistent 15-18% change in the electrical resistance (10% change in n) between the light and dark. However, the observation of this effect was not apparent, even assuming negative-U (2 electron) behavior, in the Mossbauer measurements. This was also consistent with EXAFS results. These studies do not support the broken-bond model of Chadi and Chang, which is considered to be a widely accepted atomic-scale model of the DX center. A defect complex consisting of a substitutional Sn_{rm Ga(Al) }^+ site, and a (V_{ rm III}^-Al_{ rm As}^{-2}) complex, which localizes 3 electrons and may not be a nearest-neighbor to the donor, was chosen for the DX center in the x = 0.15 sample which supports EXAFS, recent positron annihilation and these Mossbauer studies.

Analysis of structural dynamic data from Skylab. Volume 2: Skylab analytical and test model data

NASA Technical Reports Server (NTRS)

Demchak, L.; Harcrow, H.

1976-01-01

The orbital configuration test modal data, analytical test correlation modal data, and analytical flight configuration modal data are presented. Tables showing the generalized mass contributions (GMCs) for each of the thirty tests modes are given along with the two dimensional mode shape plots and tables of GMCs for the test correlated analytical modes. The two dimensional mode shape plots for the analytical modes and uncoupled and coupled modes of the orbital flight configuration at three development phases of the model are included.

Evaluation of solitary waves as a mechanism for oil transport in poroelastic media: A case study of the South Eugene Island field, Gulf of Mexico basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Ajit; Appold, Martin S.; Nunn, Jeffrey A.

Hydrocarbons in shallow reservoirs of the Eugene Island 330 field in the Gulf of Mexico basin are thought to have migrated rapidly along low permeability sediments of the Red fault zone as discrete pressure pulses from source rocks at depths of about 4.5 km. The aim of this research was to evaluate the hypothesis that these pressure pulses represent solitary waves by investigating the mechanics of solitary wave formation and motion and wave oil transport capability. A two-dimensional numerical model of Eugene Island minibasin formation predicted overpressures at the hydrocarbon source depth to increase at an average rate of 30more » Pa/yr, reaching 52 MPa by the present day and oil velocities of 1E-12 m/yr, far too low for kilometer scale oil transport to fill shallow Plio-Pleistocene reservoirs within the 3.6 million year minibasin history. Calculations from a separate one-dimensional model that used the pressure generation rate from the two-dimensional model showed that solitary waves could only form and migrate within sediments that have very low permeabilities between 1-25 to 1-24 m2 and that are highly overpressured to 91-93% of lithostatic pressure. Solitary waves were found to have a maximum pore volume of 105 m3, to travel a maximum distance of 1-2 km, and to have a maximum velocity of 1-3 m/yr. Based on these results, solitary waves are unlikely to have transported oil to the shallowest reservoirs in the Eugene Island field in a poroelastic fault gouge rheology at the pressure generation rates likely to have been caused by disequilibrium compaction and hydrocarbon generation. However, solitary waves could perhaps be important agents for oil transport in other locations where reservoirs are closer to the source rocks, where the pore space is occupied by more than one fluid, or where sudden fracturing of overpressured hydrocarbon source sediments would allow the solitary waves to propagate as shock waves. Hydrocarbons in shallow reservoirs of the Eugene Island 330 field in the Gulf of Mexico basin are thought to have migrated rapidly along low permeability sediments of the Red fault zone as discrete pressure pulses from source rocks at depths of about 4.5 km. The aim of this research was to evaluate the hypothesis that these pressure pulses represent solitary waves by investigating the mechanics of solitary wave formation and motion and wave oil transport capability. A two-dimensional numerical model of Eugene Island minibasin formation predicted overpressures at the hydrocarbon source depth to increase at an average rate of 30 Pa/yr, reaching 52 MPa by the present day and oil velocities of 1-12 m/yr, far too low for kilometer scale oil transport to fill shallow Plio-Pleistocene reservoirs within the 3.6 million year minibasin history. Calculations from a separate one-dimensional model that used the pressure generation rate from the two-dimensional model showed that solitary waves could only form and migrate within sediments that have very low permeabilities between 1-25 to 1-24 m2 and that are highly overpressured to 91-93% of lithostatic pressure. Solitary waves were found to have a maximum pore volume of 100,000 m3, to travel a maximum distance of 1-2 km, and to have a maximum velocity of 1-3 m/yr. Based on these results, solitary waves are unlikely to have transported oil to the shallowest reservoirs in the Eugene Island field in a poroelastic fault gouge rheology at the pressure generation rates likely to have been caused by disequilibrium compaction and hydrocarbon generation. However, solitary waves could perhaps be important agents for oil transport in other locations where reservoirs are closer to the source rocks, where the pore space is occupied by more than one fluid, or where sudden fracturing of overpressured hydrocarbon source sediments would allow the solitary waves to propagate as shock waves.« less

Stochastic Inversion of InSAR Data to Assess the Probability of Pressure Penetration into the Lower Caprock at In Salah

DOE PAGES

Ramirez, Abelardo; Foxall, William

2014-05-28

Stochastic inversions of InSAR data were carried out to assess the probability that pressure perturbations resulting from CO 2 injection into well KB-502 at In Salah penetrated into the lower caprock seal above the reservoir. Inversions of synthetic data were employed to evaluate the factors that affect the vertical resolution of overpressure distributions, and to assess the impact of various sources of uncertainty in prior constraints on inverse solutions. These include alternative pressure-driven deformation modes within reservoir and caprock, the geometry of a sub-vertical fracture zone in the caprock identified in previous studies, and imperfect estimates of the rock mechanicalmore » properties. Inversions of field data indicate that there is a high probability that a pressure perturbation during the first phase of injection extended upwards along the fracture zone ~ 150 m above the reservoir, and less than 50% probability that it reached the Hot Shale unit at 1500 m depth. Within the uncertainty bounds considered, it was concluded that it is very unlikely that the pressure perturbation approached within 150 m of the top of the lower caprock at the Hercynian Unconformity. The results are consistent with previous deterministic inversion and forward modeling studies.« less

Multicycle rapid thermal annealing optimization of Mg-implanted GaN: Evolution of surface, optical, and structural properties

NASA Astrophysics Data System (ADS)

Greenlee, Jordan D.; Feigelson, Boris N.; Anderson, Travis J.; Tadjer, Marko J.; Hite, Jennifer K.; Mastro, Michael A.; Eddy, Charles R.; Hobart, Karl D.; Kub, Francis J.

2014-08-01

The first step of a multi-cycle rapid thermal annealing process was systematically studied. The surface, structure, and optical properties of Mg implanted GaN thin films annealed at temperatures ranging from 900 to 1200 °C were investigated by Raman spectroscopy, photoluminescence, UV-visible spectroscopy, atomic force microscopy, and Nomarski microscopy. The GaN thin films are capped with two layers of in-situ metal organic chemical vapor deposition -grown AlN and annealed in 24 bar of N2 overpressure to avoid GaN decomposition. The crystal quality of the GaN improves with increasing annealing temperature as confirmed by UV-visible spectroscopy and the full widths at half maximums of the E2 and A1 (LO) Raman modes. The crystal quality of films annealed above 1100 °C exceeds the quality of the as-grown films. At 1200 °C, Mg is optically activated, which is determined by photoluminescence measurements. However, at 1200 °C, the GaN begins to decompose as evidenced by pit formation on the surface of the samples. Therefore, it was determined that the optimal temperature for the first step in a multi-cycle rapid thermal anneal process should be conducted at 1150 °C due to crystal quality and surface morphology considerations.

40 CFR 1042.505 - Testing engines using discrete-mode or ramped-modal duty cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Testing engines using discrete-mode or...-IGNITION ENGINES AND VESSELS Test Procedures § 1042.505 Testing engines using discrete-mode or ramped-modal... the Clean Air Act. (a) You may perform steady-state testing with either discrete-mode or ramped-modal...

Preliminary sonic boom correlation of predicted and measured levels for STS-1 entry

NASA Technical Reports Server (NTRS)

Garcia, F., Jr.; Morrison, K. M.; Jones, J. H.; Henderson, H. R.

1982-01-01

A preliminary analysis correlating peaks from sonic boom pressure signatures recorded during the descent trajectory of the Orbiter Columbia, which landed in the dry lake bed at Edwards Air Force Base (EAFB), California, with measured wind tunnel signatures extrapolated from flight altitudes to the ground has been made for Mach numbers ranging from 1.3 to 6. The flight pressure signatures were recorded by microphones positioned at ground level near the groundtrack, whereas the wind tunnel signatures were measured during a test of a 0.0041-scale model Orbiter. The agreement between overpressure estimates based on wind tunnel data using preliminary flight trajectory data and oscillograph traces from ground measurements appears reasonable at this time for the range of Mach numbers considered. More detailed studies using final flight trajectory data and digitized ground measured data will be performed.

Thermal Vacuum Chamber Repressurization with Instrument Purging

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2016-01-01

At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

Thermal Vacuum Chamber Repressurization with Instrument Purging

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2017-01-01

At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

The Range Safety Debris Catalog Analysis in Preparation for the Pad Abort One Flight Test

NASA Technical Reports Server (NTRS)

Kutty, Prasad M.; Pratt, William D.

2010-01-01

The Pad Abort One flight test of the Orion Abort Flight Test Program is currently under development with the goal of demonstrating the capability of the Launch Abort System. In the event of a launch failure, this system will propel the Crew Exploration Vehicle to safety. An essential component of this flight test is range safety, which ensures the security of range assets and personnel. A debris catalog analysis was done as part of a range safety data package delivered to the White Sands Missile Range in New Mexico where the test will be conducted. The analysis discusses the consequences of an overpressurization of the Abort Motor. The resulting structural failure was assumed to create a debris field of vehicle fragments that could potentially pose a hazard to the range. A statistical model was used to assemble the debris catalog of potential propellant fragments. Then, a thermodynamic, energy balance model was applied to the system in order to determine the imparted velocity to these propellant fragments. This analysis was conducted at four points along the flight trajectory to better understand the failure consequences over the entire flight. The methods used to perform this analysis are outlined in detail and the corresponding results are presented and discussed.

77 FR 70429 - Gulf South Pipeline Company, LP; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... compressor stations in Mississippi and Alabama. The SEME Project would provide about 450 million standard... station, five mainline valves, two pig \\1\\ launchers, two pig receivers, and overpressure protection... three new compressor stations, including: [ssquf] The Forrest Compressor Station, which would be located...

JPRS Report Central Eurasia Military Affairs Defense Industry and Conversion

DTIC Science & Technology

1993-06-30

concrete and water are uti - sure compensators, pipes and armature. Overpressure lized as biological shielding materials. that exceeds the pressure in...some antacid tablets. The pharmacist It was not one of them, but 80 percent of the association’s looked at me in amazement, as though I had fallen from

The Overpressure Epidemic of 1884 and the Culture of Nineteenth-Century Schooling

ERIC Educational Resources Information Center

Middleton, J.

2004-01-01

The overworking of children is a popular stereotype of Victorian schooling. The familiar imagery of nineteenth-century education draws heavily on the Dickensian model of the brutal school, drawn from "Nicholas Nickelby"'s Dotheboys Hall and Gradgrind's school from "Hard Times". Though caricatures, Dickens's images of schools represented…

33 CFR 154.2203 - Facility requirements for barge vapor overpressure and vacuum protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... displacement system must provide a pressure-sensing device that activates an alarm that satisfies the... located in the fluid displacement system's piping downstream of any devices that could potentially isolate... to inject the fluid. (d) A fluid displacement system must provide a pressure-sensing device that is...

A comparison of the startle effects resulting from exposure to two levels of simulated sonic booms.

DOT National Transportation Integrated Search

1973-12-01

Subjects were exposed indoors to simulated sonic booms having outside overpressures of 50 and 150 N/sq m. Rise times were held constant at 5.5 msecs. In addition to the outside measurements, inside measures of dBlin and dBA were also obtained. Subjec...

Preliminary Investigation of Origanum onites Essential Oil by Overpressured Layer Chromatography and BioArena

USDA-ARS?s Scientific Manuscript database

Origanum is a genus of about 20 species of aromatic herbs in the family Lamiaceae, native to the Mediterranean region east to eastern Asia. The genus includes some important culinary herbs, including Marjoram and Oregano. Origanum onites (Turkish Oregano) oil and its major compounds were separated ...

33 CFR 154.2103 - Facility requirements for vessel vapor overpressure and vacuum protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... HAZARDOUS MATERIAL IN BULK Marine Vapor Control Systems Transfer Facilities-Vcs Design and Installation... rate, unless there is experimental data for actual vapor growth for turbulent transferring under the... vapor growth. (b) A facility VCS must be designed to prevent the pressure in a vessel's cargo tanks from...

78 FR 52998 - Waiver to Space Exploration Technologies Corporation of Acceptable Risk Limit for Launch

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-27

... risk. The presence of inversion layers at VAFB is common, and results in the reflection of shock waves... caused without the reflection from the inversion layer. Chances of advantageous weather conditions during... experiences unique weather conditions that exacerbate far field blast overpressure from a launch. An inversion...

Summary of Sonic Boom Rise Times Observed During FAA Community Response Studies over a 6-Month Period in the Oklahoma City Area

NASA Technical Reports Server (NTRS)

Maglieri, Domenic J.; Sothcott, Victor E.

1990-01-01

The sonic boom signature data acquired from about 1225 supersonic flights, over a 6-month period in 1964 in the Oklahoma City area, was enhanced with the addition of data relating to rise times and total signature duration. These later parameters, not available at the time of publication of the original report on the Oklahoma City sonic boom exposures, are listed in tabular form along with overpressure, positive impulse, positive duration, and waveform category. Airplane operating information along with the surface weather observations are also included. Sonic boom rise times include readings to the 1/2, 3/4, and maximum overpressure values. Rise time relative probabilities for various lateral locations from the ground track of 0, 5, and 10 miles are presented along with the variation of rise times with flight altitude. The tabulated signature data, along with corresponding airplane operating conditions and surface and upper level atmospheric information, are also available on electronic files to provide it in the format for more efficient and effective utilization.

Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004-2008 history of dome growth and deformation

USGS Publications Warehouse

Mastin, Larry G.; Lisowski, Mike; Roeloffs, Evelyn; Beeler, Nick

2009-01-01

The history of dome growth and geodetic deflation during the 2004-2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004-2008 are consistent with eruption from a 10-25 km3 reservoir containing 0.5-2% bubbles, an initial overpressure of 10-20 MPa, and no significant, sustained recharge. During the eruption we used curve fits to project the eruption's final duration and volume. Early projections predicted a final volume only about half of the actual value; but projections increased with each measurement, implying a temporal increase in reservoir volume or compressibility. A simple interpretation is that early effusion was driven by a 5-10 km3, integrated core of fluid magma. This core expanded with time through creep of semi-solid magma and host rock.

Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004-2008 history of dome growth and deformation

USGS Publications Warehouse

Mastin, L.G.; Lisowski, M.; Roeloffs, E.; Beeler, N.

2009-01-01

The history of dome growth and geodetic deflation during the 2004-2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004-2008 are consistent with eruption from a 10-25 km3 reservoir containing 0.5-2% bubbles, an initial overpressure of 10-20 MPa, and no significant, sustained recharge. During the eruption we used curve fits to project the eruption's final duration and volume. Early projections predicted a final volume only about half of the actual value; but projections increased with each measurement, implying a temporal increase in reservoir volume or compressibility. A simple interpretation is that early effusion was driven by a 5-10 km3, integrated core of fluid magma. This core expanded with time through creep of semi-solid magma and host rock. Copyright 2009 by the American Geophysical Union.

Study of Vapour Cloud Explosion Impact from Pressure Changes in the Liquefied Petroleum Gas Sphere Tank Storage Leakage

NASA Astrophysics Data System (ADS)

Rashid, Z. A.; Suhaimi Yeong, A. F. Mohd; Alias, A. B.; Ahmad, M. A.; AbdulBari Ali, S.

2018-05-01

This research was carried out to determine the risk impact of Liquefied Petroleum Gas (LPG) storage facilities, especially in the event of LPG tank explosion. In order to prevent the LPG tank explosion from occurring, it is important to decide the most suitable operating condition for the LPG tank itself, as the explosion of LPG tank could affect and cause extensive damage to the surrounding. The explosion of LPG tank usually occurs due to the rise of pressure in the tank. Thus, in this research, a method called Planas-Cuchi was applied to determine the Peak Side-On Overpressure (Po) of the LPG tank during the occurrence of explosion. Thermodynamic properties of saturated propane, (C3H8) have been chosen as a reference and basis of calculation to determine the parameters such as Explosion Energy (E), Equivalent Mass of TNT (WTNT), and Scaled Overpressure (PS ). A cylindrical LPG tank in Feyzin Refinery, France was selected as a case study in this research and at the end of this research, the most suitable operating pressure of the LPG tank was determined.

South-American plate advance and forced Andean trench retreat as drivers for transient flat subduction episodes.

PubMed

Schepers, Gerben; van Hinsbergen, Douwe J J; Spakman, Wim; Kosters, Martha E; Boschman, Lydian M; McQuarrie, Nadine

2017-05-16

At two trench segments below the Andes, the Nazca Plate is subducting sub-horizontally over ∼200-300 km, thought to result from a combination of buoyant oceanic-plateau subduction and hydrodynamic mantle-wedge suction. Whether the actual conditions for both processes to work in concert existed is uncertain. Here we infer from a tectonic reconstruction of the Andes constructed in a mantle reference frame that the Nazca slab has retreated at ∼2 cm per year since ∼50 Ma. In the flat slab portions, no rollback has occurred since their formation at ∼12 Ma, generating 'horse-shoe' slab geometries. We propose that, in concert with other drivers, an overpressured sub-slab mantle supporting the weight of the slab in an advancing upper plate-motion setting can locally impede rollback and maintain flat slabs until slab tearing releases the overpressure. Tear subduction re-establishes a continuous slab and allows the process to recur, providing a mechanism for the transient character of flat slabs.

Numerical study of blast characteristics from detonation of homogeneous explosives

NASA Astrophysics Data System (ADS)

Balakrishnan, Kaushik; Genin, Franklin; Nance, Doug V.; Menon, Suresh

2010-04-01

A new robust numerical methodology is used to investigate the propagation of blast waves from homogeneous explosives. The gas-phase governing equations are solved using a hybrid solver that combines a higher-order shock capturing scheme with a low-dissipation central scheme. Explosives of interest include Nitromethane, Trinitrotoluene, and High-Melting Explosive. The shock overpressure and total impulse are estimated at different radial locations and compared for the different explosives. An empirical scaling correlation is presented for the shock overpressure, incident positive phase pressure impulse, and total impulse. The role of hydrodynamic instabilities to the blast effects of explosives is also investigated in three dimensions, and significant mixing between the detonation products and air is observed. This mixing results in afterburn, which is found to augment the impulse characteristics of explosives. Furthermore, the impulse characteristics are also observed to be three-dimensional in the region of the mixing layer. This paper highlights that while some blast features can be successfully predicted from simple one-dimensional studies, the growth of hydrodynamic instabilities and the impulsive loading of homogeneous explosives require robust three-dimensional investigation.

Assessing Produced Water Management Issues with Increasing U.S. Tight Oil Production

NASA Astrophysics Data System (ADS)

Scanlon, B. R.; Reedy, R. C.; Murray, K. E.; Weingarten, M.

2017-12-01

U.S. oil fields have been producing about 10 times more water than oil for decades; however, problems with managing this produced water, including over-pressuring and induced seismicity, have only become apparent with the recent increases in oil production from unconventional reservoirs. This study involved quantifying spatial and temporal variability in produced water volumes and evaluating issues with managing this produced water using data from the major U.S. unconventional/conventional oil plays (Bakken, Permian, and Eagle Ford plays, and Oklahoma). The primary difference between recent and historical produced water management is the inability to inject the produced water back into the unconventional low permeability or dewatered oil reservoirs. Disposing of this produced water into non-oil producing horizons using salt water disposal wells has been linked to over-pressuring in shallow geologic units in the Bakken and Permian basins and to induced seismicity in Oklahoma. These issues with produced water management can be partially alleviated by reusing/recycling produced water for hydraulic fracturing, which seems particularly promising in the Permian Basin.

Sonic Booms in Atmospheric Turbulence (SonicBAT) Ground Measurements in a Hot Desert Climate

NASA Technical Reports Server (NTRS)

Haering, Edward A., Jr.

2017-01-01

The Sonic Booms in Atmospheric Turbulence (SonicBAT) Project flew a series of 20 F-18 flights with 69 supersonic passes at Edwards Air Force Base in July 2016 to quantify the effect of atmospheric turbulence on sonic booms. Most of the passes were at a pressure altitude of 32,000 feet and a Mach number of 1.4, yielding a nominal sonic boom overpressure of 1.6 pounds per square foot. Atmospheric sensors such as GPS sondeballoons, Sonic Detection and Ranging (SODAR) acoustic sounders, and ultrasonic anemometers were used to characterize the turbulence state of the atmosphere for each flight. Spiked signatures in excess of 7 pounds per square foot were measured at some locations, as well as rounded sonic-boom signatures with levels much lower than the nominal. This presentation will quantify the range of overpressure and Perceived Level of the sonic boom as a function of turbulence parameters, and also present the spatial variation of these quantities over the array. Comparison with historical data will also be shown.

Optimizing Blasting’s Air Overpressure Prediction Model using Swarm Intelligence

NASA Astrophysics Data System (ADS)

Nur Asmawisham Alel, Mohd; Ruben Anak Upom, Mark; Asnida Abdullah, Rini; Hazreek Zainal Abidin, Mohd

2018-04-01

Air overpressure (AOp) resulting from blasting can cause damage and nuisance to nearby civilians. Thus, it is important to be able to predict AOp accurately. In this study, 8 different Artificial Neural Network (ANN) were developed for the purpose of prediction of AOp. The ANN models were trained using different variants of Particle Swarm Optimization (PSO) algorithm. AOp predictions were also made using an empirical equation, as suggested by United States Bureau of Mines (USBM), to serve as a benchmark. In order to develop the models, 76 blasting operations in Hulu Langat were investigated. All the ANN models were found to outperform the USBM equation in three performance metrics; root mean square error (RMSE), mean absolute percentage error (MAPE) and coefficient of determination (R2). Using a performance ranking method, MSO-Rand-Mut was determined to be the best prediction model for AOp with a performance metric of RMSE=2.18, MAPE=1.73% and R2=0.97. The result shows that ANN models trained using PSO are capable of predicting AOp with great accuracy.

Influence of Mixed Mode I-Mode II Loading on Fatigue Delamination Growth Characteristics of a Graphite Epoxy Tape Laminate

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; Johnston, William M., Jr.

2014-01-01

Mixed mode I-mode II interlaminar tests were conducted on IM7/8552 tape laminates using the mixed-mode bending test. Three mixed mode ratios, G(sub II)/G(sub T) = 0.2, 0.5, and 0.8, were considered. Tests were performed at all three mixed-mode ratios under quasi-static and cyclic loading conditions, where the former static tests were used to determine initial loading levels for the latter fatigue tests. Fatigue tests at each mixed-mode ratio were performed at four loading levels, Gmax, equal to 0.5G(sub c), 0.4G(sub c), 0.3G(sub c), and 0.2G(sub c), where G(sub c) is the interlaminar fracture toughness of the corresponding mixed-mode ratio at which a test was performed. All fatigue tests were performed using constant-amplitude load control and delamination growth was automatically documented using compliance solutions obtained from the corresponding quasi-static tests. Static fracture toughness data yielded a mixed-mode delamination criterion that exhibited monotonic increase in Gc with mixed-mode ratio, G(sub II)/G(sub T). Fatigue delamination onset parameters varied monotonically with G(sub II)/G(sub T), which was expected based on the fracture toughness data. Analysis of non-normalized data yielded a monotonic change in Paris law exponent with mode ratio. This was not the case when normalized data were analyzed. Fatigue data normalized by the static R-curve were most affected in specimens tested at G(sub II)/G(sub T)=0.2 (this process has little influence on the other data). In this case, the normalized data yielded a higher delamination growth rate compared to the raw data for a given loading level. Overall, fiber bridging appeared to be the dominant mechanism, affecting delamination growth rates in specimens tested at different load levels and differing mixed-mode ratios.

Comparison of Mode II and III Monotonic and Fatigue Delamination Onset Behavior for Carbon/Toughened Epoxy Composites

NASA Technical Reports Server (NTRS)

Li, Jian; OBrien, T. Kevin; Lee, Shaw Ming

1997-01-01

Monotonic and fatigue tests were performed to compare the Mode II and III interlaminar fracture toughness and fatigue delamination onset for Tenax-HTA/R6376 carbon/toughened epoxy composites. The Mode II interlaminar fracture toughness and fatigue delamination onset were characterized using the end-notched flexure (ENF) test while the Mode III interlaminar fracture toughness and fatigue delamination onset were characterized by using the edge crack torsion (ECT) test. Monotonic tests show that the Mode III fracture toughness is higher than the Mode II fracture toughness. Both Mode II and III cyclic loading greatly increases the tendency for a delamination to grow relative to a single monotonically increasing load. Under fatigue loading, the Mode III specimen also has a longer life than the Mode II specimen.

Evaluation of the Edge Crack Torsion (ECT) Test for Mode 3 Interlaminar Fracture Toughness of Laminated Composites

NASA Technical Reports Server (NTRS)

Li, Jian; Lee, Edward W.; OBrien, T. Kevin; Lee, Shaw Ming

1996-01-01

An analytical and experimental investigation was carried out on G40-800/R6376 graphite epoxy laminates to evaluate the Edge Crack Torsion (ECT) test as a candidate for a standard Mode 3 interlaminar fracture toughness test for laminated composites. The ECT test consists of a (90/(+/- 45)(sub 3)/(+/- 45)(sub 3)/90))(sub s) laminate with a delamination introduced by a non-adhesive film at the mid-plane along one edge and loaded in a special fixture to create torsion along the length of the laminate. Dye penetrate enhanced X-radiograph of failed specimens revealed that the delamination initiated at the middle of the specimen length and propagated in a self similar manner along the laminate mid-plane. A three-dimensional finite element analysis was performed that indicated that a pure Mode 3 delamination exists at the middle of specimen length away from both ends. At the ends near the loading point a small Mode 2 component exists. However, the magnitude of this Mode 2 strain energy release rate at the loading point is small compared to the magnitude of Mode 3 component in the mid-section of the specimen. Hence, the ECT test yielded the desired Mode 3 delamination. The Mode 3 fracture toughness was obtained from a compliance calibration method and was in good agreement with the finite element results. Mode 2 End-Notched Flexure (ENF) tests and Mode 1 Double Cantilever Beam (DCB) tests were also performed for the same composite material. The Mode 1 fracture toughness was much smaller than both the Mode 2 and Mode 3 fracture toughness. The Mode 2 fracture toughness was found to be 75% of the Mode 3 fracture toughness.

Thermal state of the Arkoma Basin and the Anadarko Basin, Oklahoma

NASA Astrophysics Data System (ADS)

Lee, Youngmin

1999-12-01

One of the most fundamental physical processes that affects virtually all geologic phenomena in sedimentary basins is the flow of heat from the Earth's interiors. The Arkoma Basin and the Anadarko Basin, Oklahoma, are a prolific producer of both oil and natural gas. Both basins also have important geologic phenomena. Understanding the thermal state of the these basins is crucial to understanding the timing and extent of hydrocarbon generation, the genesis of Mississippi Valley-type ore deposits, and the origin of overpressures in the Anadarko Basin. In chapter one, heat flow and heat production in the Arkoma basin and Oklahoma Platform are discussed. Results of this study are not generally supportive of theories which invoke topographically driven regional groundwater flow from the Arkoma Basin in Late Pennsylvanian-Early Permian time (˜290 Ma) to explain the genesis of geologic phenomena. In chapter 2, different types of thermal conductivity temperature corrections that are commonly applied in terrestrial heat flow studies are evaluated. The invariance of the relative rankings with respect to rock porosity suggests the rankings may be valid with respect to in situ conditions. Chapter three addresses heat flow and thermal history of the Anadarko Basin and the western Oklahoma Platform. We found no evidence for heat flow to increase significantly from the Anadarko Basin in the south to the Oklahoma Platform to the north. In chapter four, overpressures in the Anadarko Basin, southwestern Oklahoma are discussed. Using scale analyses and a simple numerical model, we evaluated two endmember hypotheses (compaction disequilibrium and hydrocarbon generation) as possible causes of overpressuring. Geopressure models which invoke compaction disequilibrium do not appear to apply to the Anadarko Basin. The Anadarko Basin belongs to a group of cratonic basins which are tectonically quiescent and are characterized by the association of abnormal pressures with natural gas. (Abstract shortened by UMI.)

Long-times series of infrasonic records at open-vents volcanoes (Yasur volcano, Vanuatu, 2003-2014): the remarkable temporal stability of magma viscosity

NASA Astrophysics Data System (ADS)

Vergniolle, S.; Souty, V.; Zielinski, C.; Bani, P.; LE Pichon, A.; Lardy, M.; Millier, P.; Herry, P.; Todman, S.; Garaebiti, E.

2017-12-01

Open-vents volcanoes, often presenting series of Strombolian explosions of various intensity, are responding, although with a delay, to any changes in the degassing pattern, providing a quasi-direct route to processes at depth. Open-vents volcanoes display a persistent volcanic activity, although of variable intensity. Long-times series at open-vents volcanoes could therefore be key measurements to unravel physical processes at the origin of Strombolian explosions and be crucial for monitoring. Continuous infrasonic records can be used to estimate the gas volume expelled at the vent during explosions (bursting of a long slug). The gas volume of each explosion is deduced from a series of two successive integrations of acoustic pressure (monopole). Here we analysed more than 4 years of infrasonic records at Yasur volcano (Vanuatu), spanning between 2003 and 2014 and organised into 8 main quasi-continuous periods. The relationship between the gas volume of each explosion and its associated maximum positive acoustic pressure, a proxy for the inner gas overpressure at bursting, shows a remarkably stable trend over the 8 periods. Two main trends exists, one which covers the full range of acoustic pressures (called « strong explosions ») and the second which represents explosions with a large gas volume and mild acoustic pressure. The class of « strong explosions » clearly follows the model of Del Bello et al. (2012), which shows that the inner gas overpressure at bursting, here empirically measured by the maximum acoustic pressure, is proportional to the gas volume. Constrains on magma viscosity and conduit radius, are deduced from this trend and from the gas volume at the transition passive-active degassing. The remarkable stability of this trend over time suggests that 1) the magma viscosity is stable at the depth where gas overpressure is produced within the slug and 2) any potential changes in magma viscosity occur very close to the top of the magma column.

Using a gel/plastic surrogate to study the biomechanical response of the head under air shock loading: a combined experimental and numerical investigation.

PubMed

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.

Laboratory Studies of Survival Limits of Bacteria During Shock Compression: Application to Impacts on the Early Earth

NASA Astrophysics Data System (ADS)

Willis, M. J.; Ahrens, T. J.; Bertani, L. E.; Nash, C. Z.

2004-12-01

Shock recovery experiments on suspensions of 106 mm-3 E. coli bacteria contained in water-based medium, within stainless steel containers, are used to simulate the impact environment of bacteria residing in water-filled cracks in rocks. Early Earth life is likely to have existed in such environments. Some 10-2 to 10-4 of the bacteria population survived initial (800 ns duration) shock pressures in water of 219 and 260 MPa. TEM images of shock recovered bacteria indicate cell wall indentations and rupture, possibly induced by inward invasion of medium into the cell wall. Notably cell wall rupture occurs dynamically at ˜0.1 times the static pressures E.coli have been demonstrated (Sharma et al., 2002) to survive and may be caused by Rayleigh-Taylor instabilities. We infer the invading fluid pressure may exceed the tensile strength of the cell wall. We assume the overpressures are limited to the initial shock pressure in water. Parameters for the Grady & Lipkin (1980) model of tensile failure versus time-scale (strain rate) are fit to present data, assuming that at low strain rates, overpressures exceeding cell Turgor pressure require ˜103 sec. This model, if validated by experiments at other timescales, may permit using short loading duration laboratory data to infer response of organisms to lower shock overpressures for the longer times (100 to 103 s) of planetary impacts. An Ahrens & O'Keefe (1987) shock attenuation model is then applied for Earth impactors. This model suggests that Earth impactors of radius 1.5 km induce shocks within water-filled cracks in rock to dynamic pressure such that stresses exceeding the survivability threshold of E. coli bacteria, to radii of 1.7-2.6×102 km. In contrast, a giant (1500 km radius) impactor produces a non survival zone for E. coli that encompasses the entire Earth.

From hydrofracture to gaseofracture in porous rocks: influence of the nature of the injection fluid on the process

NASA Astrophysics Data System (ADS)

Johnsen, O.; Chevalier, C.; Toussaint, R.; Lindner, A.; Niebling, M.; Schmittbuhl, J.; Maloy, K. J.; Clement, E.; Flekkoy, E. G.

2009-04-01

We present experimental systems where we inject a fluid at high pressure in a poorly cohesive porous material saturated with the same fluid. This fluid is either a highly compressible gas (air), or an almost incompressible and viscous fluid (oil), in an otherwise identical porous matrix. We compare both situations. These porous materials are designed as analogs to real rocks in terms of processes, but their cohesion and geometry are tuned so that the hydrofracture process can be followed optically in the lab, in addition to the ability to follow the imposed pressure and fluxes. Namely, we work with lowly cohesive granular materials, confined in thin elongated Hele-Shaw cell, and follow it with high speed cameras. The fluid is injected on the side of the material, and the injection overpressure is maintained constant after the start. At sufficiently high overpressures, the mobilization of grains is observed, and the formation of hydrofracture fingering patterns is followed and analyzed quantitatively. The two situations where air is injected and where oil is injected are compared together. Many striking similarities are observed between both situations about the shape selections and dynamics, when time is rescaled according to the viscosity of the interstitial fluid. Some differences survive in the speed of the traveling hydrofracture, and their physical origin is discussed. In practice, this problem is relevant for important aspects in the formation and sustenance of increased permeability macroporous networks as demonstrated in nature and industry in many situations. E.g., in active hydrofracture in boreholes, piping/internal erosion in soils and dams, sand production in oil or water wells, and wormholes in oil sands. It is also important to understand the formation of macroporous channels, and the behavior of confined gouges when overpressured fluids are mobilized in seismic sources. Indeed, the formation of preferential paths in this situation can severely affect the fluid and heat transport properties in this situations, and thus affect the pore pressurization effects.

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

PubMed Central

Skotak, Maciej; Alay, Eren; Chandra, Namas

2018-01-01

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 compared with others. PMID:29467718

­­Clastic Pipes on Mars: Evidence for a Near Surface Groundwater System

NASA Astrophysics Data System (ADS)

Wheatley, D. F.; Chan, M. A.; Okubo, C. H.

2017-12-01

Clastic pipes, a type of vertical, columnar injectite, occur throughout the terrestrial stratigraphic record and are identified across many Martian terrains. Terrestrial pipe analogs can aid in identifying clastic pipes on Mars to understand their formation processes and their implications for a past near-surface groundwater system. On Earth, clastic pipes form through fluidization of overpressurized sediment. Fluidization occurs when the upward frictional (i.e., drag) forces of escaping fluids overpower the downward acting gravitational force. To create the forces necessary for pipe formation requires overpressurization of a body of water-saturated porous media overlain by a low permeability confining layer. As the pressure builds, the confining layer eventually fractures and the escaping fluids fluidize the porous sediment causing the sediment to behave like a fluid. These specific formation conditions record evidence of a violent release of fluid-suspended sediment including brecciation of the host and sealing material, internal outward grading/sorting that results in a coarser-grained commonly better cemented outer rind, traction structures, and a cylindrical geometry. Pipes form self-organized, dispersed spatial relationships due to the efficient diffusion of overpressured zones in the subsurface and the expulsion of sediment under pressure. Martian pipes occur across the northern lowlands, dichotomy boundary, and southern highlands in various forms of erosional relief ranging from newer eruption structures to eroded cylindrical/conical mounds with raised rims to highly eroded mounds/hills. Similar to terrestrial examples, Martian pipes form in evenly-spaced, self-organized arrangements. The pipes are typically internally massive with a raised outer rim (interpreted as a sorted, coarser-grained, better-cemented rim). This evidence indicates that Martian pipes formed through fluidization, which requires a near-surface groundwater system. Pipes create a window into the subsurface by excavating subsurface sediment and waters. After emplacement, pipes can also act as fluid conduits, channeling post-depositional fluid flow. The preferential porosity and flow paths may make the pipes an ideal exploration target for microbial life.

Air Blasts from Cased and Uncased Explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glenn, L. A.

2016-04-12

The problem of a spherical blast in air is solved using the STUN code. For bare charges, the calculations are shown to be in excellent agreement with previous published results. It is demonstrated that, for an unconfined (uncased) chemical explosive, both range and time to effect scale inversely as the cube root of the yield and directly as the cube root of the ambient air density. It is shown that the peak overpressure decays to roughly 1/10 of ambient pressure in a scaled range of roughly 10 m/kg 1/3 at sea level. At a height of 30 km, where themore » ambient density is a factor of 64 less, the range to the same decay increases to 40 m/kg 1/3 . As a direct result of the scaling a single calculation suffices for all charge sizes and altitudes. Although the close-in results are sensitive to the nature of the explosive source and the equation of state of the air, this sensitivity is shown to virtually disappear at scaled ranges > 0.5 m/kg 1/3 . For cased explosives the case thickness introduces an additional scale factor. Moreover, when the blast wave arrives at the inner case radius the case begins to expand. Fracture occurs when a critical value of the resulting hoop strain is reached, causing the case to shatter into fragments. A model is proposed to describe the size distribution of the fragments and their subsequent motion via drag interaction with the explosion products and ambient air. It is shown that a significant fraction of the charge energy is initially transmitted to the case fragments in the form of kinetic energy; for example, a 1 kg spherical charge with a 5 mm thick steel case has almost 29% of the total charge energy as initial kinetic energy of case fragments. This percentage increases with increasing case thickness and decreases with increasing charge size. The peak overpressure at a given range is 70-85% for cased explosives as compared with uncased and the peak impulse per unit area is 90-95%. The peak overpressure and impulse also decrease rapidly with altitude. The effect of the fragments is to increase lethality. Whereas at a scaled range of 10 m/kg 1/3 , the peak overpressure is an order of magnitude less than the ambient pressure, the number of fragments per unit area is close to 1 m -2 /kg 1/3 , independent of case thickness or altitude. For sufficient ratio of case-to- explosive mass, the number of fragments scales with the cube root of the yield and is independent of case thickness.« less

Pneumatic fractures in Confined Granular Media

NASA Astrophysics Data System (ADS)

Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih

2016-04-01

We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during experiments, where we aim to localize acoustic events and correlate them with the optical observations. [1] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Dynamic aerofracture of dense granular packings. Phys. Rev. E86, 061315. doi:10.1103/PhysRevE.86.061315 [2] Niebling M.J., Toussaint R., Flekkøy E.G. and Måløy K.J. (2012) Numerical studies of aerofractures in porous media. Rev. Cub. Fis. 29, 1E66 [3] Turkaya S., Toussaint R., Eriksen F.K., Zecevic M., Daniel G., Flekkøy E.G. and Måløy K.J. (2015)Bridging aero-fracture evolution with the characteristics of the acoustic emissions in a porous medium. Front. Phys. 3:70. doi: 10.3389/fphy.2015.00070

40 CFR 1042.525 - How do I adjust emission levels to account for infrequently regenerating aftertreatment devices?

Code of Federal Regulations, 2010 CFR

2010-07-01

... this section for how to adjust discrete-mode testing. For this section, “regeneration” means an... ramped-modal cycle, or on average less than once per typical mode in a discrete-mode test. (a) Developing... modes of a discrete-mode steady-state test. You may use either of the following different approaches for...

Verification of Ares I Liftoff Acoustic Environments via the Ares I Scale Model Acoustic Test

NASA Technical Reports Server (NTRS)

Counter, Douglas D.; Houston, Janice D.

2012-01-01

Launch environments, such as Liftoff Acoustic (LOA) and Ignition Overpressure (IOP), are important design factors for any vehicle and are dependent upon the design of both the vehicle and the ground systems. The NASA Constellation Program had several risks to the development of the Ares I vehicle linked to LOA which are used in the development of the vibro-acoustic environments. The risks included cost, schedule and technical impacts for component qualification due to high predicted vibro-acoustic environments. One solution is to mitigate the environment at the component level. However, where the environment is too severe to mitigate at the component level, reduction of the launch environments is required. The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the predicted Ares I launch environments and to determine the acoustic reduction for the LOA environment with an above deck water sound suppression system. The test article included a 5% scale Ares I vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments. The ASMAT results are compared to the Ares I LOA predictions and water suppression effectiveness results are presented.

Verification of Ares I Liftoff Acoustic Environments via the Ares Scale Model Acoustic Test

NASA Technical Reports Server (NTRS)

Counter, Douglas D.; Houston, Janice D.

2012-01-01

Launch environments, such as Liftoff Acoustic (LOA) and Ignition Overpressure (IOP), are important design factors for any vehicle and are dependent upon the design of both the vehicle and the ground systems. The NASA Constellation Program had several risks to the development of the Ares I vehicle linked to LOA which are used in the development of the vibro-acoustic environments. The risks included cost, schedule and technical impacts for component qualification due to high predicted vibro-acoustic environments. One solution is to mitigate the environment at the component level. However, where the environment is too severe to mitigate at the component level, reduction of the launch environments is required. The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the predicted Ares I launch environments and to determine the acoustic reduction for the LOA environment with an above deck water sound suppression system. The test article included a 5% scale Ares I vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments. The ASMAT results are compared to the Ares I LOA predictions and water suppression effectiveness results are presented.

Lunar floor-fractured craters as magmatic intrusions: Geometry, modes of emplacement, associated tectonic and volcanic features, and implications for gravity anomalies

NASA Astrophysics Data System (ADS)

Jozwiak, Lauren M.; Head, James W.; Wilson, Lionel

2015-03-01

Lunar floor-fractured craters are a class of 170 lunar craters with anomalously shallow, fractured floors. Two end-member processes have been proposed for the floor formation: viscous relaxation, and subcrater magmatic intrusion and sill formation. Recent morphometric analysis with new Lunar Reconnaissance Orbiter Laser Altimeter (LOLA) and image (LROC) data supports an origin related to shallow magmatic intrusion and uplift. We find that the distribution and characteristics of the FFC population correlates strongly with crustal thickness and the predicted frequency distribution of overpressurization values of magmatic dikes. For a typical nearside lunar crustal thickness, dikes with high overpressurization values favor surface effusive eruptions, medium values favor intrusion and sill formation, and low values favor formation of solidified dikes concentrated lower in the crust. We develop a model for this process, make predictions for the morphologic, morphometric, volcanic, and geophysical consequences of the process and then compare these predictions with the population of observed floor-fractured craters. In our model, the process of magmatic intrusion and sill formation begins when a dike propagates vertically towards the surface; as the dike encounters the underdense brecciated region beneath the crater, the magmatic driving pressure is insufficient to continue vertical propagation, but pressure in the stalled dike exceeds the local lithostatic pressure. The dike then begins to propagate laterally forming a sill which does not propagate past the crater floor region because increased overburden pressure from the crater wall and rim crest pinch off the dike at this boundary; the sill then continues to inflate, further raising and fracturing the brittle crater floor. When the intrusion diameter to intrusion depth ratio is smaller than a critical value, the intrusion assumes a laccolith shape with a domed central region. When the ratio exceeds a critical value, the intrusion concentrates bending primarily at the periphery, resulting in a flat, tabular intrusion. We predict that this process will result in concentric fractures over the region of greatest bending. This location is close to the crater wall in large, flat-floored craters, as observed in the crater Humboldt, and interior to the crater over the domed floor in smaller craters, as observed in the crater Vitello. A variety of volcanic features are predicted to be associated with the solidification and degassing of the intrusion; these include: (1) surface lava flows associated with concentric fractures (e.g., in the crater Humboldt); (2) vents with no associated pyroclastic material, from the deflation of under-pressurized magmatic foam (e.g., the crater Damoiseau); and (3) vents with associated pyroclastic deposits from vulcanian eruptions of highly pressurized magmatic foam (e.g., the crater Alphonsus). The intrusion of basaltic magma beneath the crater is predicted to contribute a positive component to the Bouguer gravity anomaly; we assess the predicted Bouguer anomalies associated with FFCs and outline a process for their future interpretation. We conclude that our proposed mechanism serves as a viable formation process for FFCs and accurately predicts numerous morphologic, morphometric, and geophysical features associated with FFCs. These predictions can be further tested using GRAIL (Gravity Recovery and Interior Laboratory) data.

Behavioral, autonomic, and subjective reactions to low- and moderate-level simulated sonic booms : a report of two experiments and a general evaluation of sonic boom startle effects.

DOT National Transportation Integrated Search

1974-09-01

Two separate studies are reported. The first attempted to determine a sonic boom exposure level below which startle reactions would not occur. Subjects were exposed indoors to six simulated sonic booms having various outside overpressures. In the sec...

33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vapor at a rate of not less than 1.25 times the facility's maximum liquid transfer rate for cargo for... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS... in the vessel's cargo tanks within this range at any cargo transfer rate less than or equal to the...

Biological Evaluation, Overpressured Layer Chromatography (OPLC) separation and Isolation of a New Acetylenic Derivative Compound from Prangos platychlaena ssp. platychlaena Fruit Essential Oils

USDA-ARS?s Scientific Manuscript database

In the present work, fruits of Prangos platychlaena Boiss. ex Tchihat. ssp. platychlaena (Apiaceae) collected from eastern (Sample A) and central (Sample B) parts of Turkey were subjected to hydrodistillation to yield essential oils (EOs). The chemical composition of P. platychlaena ssp. platychlaen...

Interface Lattice Engineering of Si Composite Wafers for Large-Format HgCdTe Infrared Focal Plane Arrays

DTIC Science & Technology

2012-08-07

sealed quartz ampoule under a mercury overpressure in a conventional clam-shell furnace . The reduction in the dislocation density has been studied as...46 2.6.4 Etch Pit Characterization . . . . . . . . . . . . . . . . . . . . . . . . 46 5 3 Furnace Setup and Calibration...Setup . . . . . . . . . . . . . . . . . . . . . . . 54 3.1.2 Furnace Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4 In Situ

Passive cooling system for nuclear reactor containment structure

DOEpatents

Gou, Perng-Fei; Wade, Gentry E.

1989-01-01

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

24 CFR Appendix II to Subpart C of... - Development of Standards; Calculation Methods

Code of Federal Regulations, 2010 CFR

2010-04-01

... radiation being emitted. The radiation can cause severe burn, injuries and even death to exposed persons... even death. Since it is assumed that children and the elderly could not take refuge behind walls or run... suffer any serious injury. Using this as the safety standard for blast overpressure, nomographs have been...

Design of an Indoor Sonic Boom Simulator at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Klos, Jacob; Sullivan, Brenda M.; Shepherd, Kevin P.

2008-01-01

Construction of a simulator to recreate the soundscape inside residential buildings exposed to sonic booms is scheduled to start during the summer of 2008 at NASA Langley Research Center. The new facility should be complete by the end of the year. The design of the simulator allows independent control of several factors that create the indoor soundscape. Variables that will be isolated include such factors as boom duration, overpressure, rise time, spectral shape, level of rattle, level of squeak, source of rattle and squeak, level of vibration and source of vibration. Test subjects inside the simulator will be asked to judge the simulated soundscape, which will represent realistic indoor boom exposure. Ultimately, this simulator will be used to develop a functional relationship between human response and the sound characteristics creating the indoor soundscape. A conceptual design has been developed by NASA personnel, and is currently being vetted through small-scale risk reduction tests that are being performed in-house. The purpose of this document is to introduce the conceptual design, identify how the indoor response will be simulated, briefly outline some of the risk reduction tests that have been completed to vet the design, and discuss the impact of these tests on the simulator design.

Using Artificial Neural Networks to Predict the Presence of Overpressured Zones in the Anadarko Basin, Oklahoma

NASA Astrophysics Data System (ADS)

Cranganu, Constantin

2007-10-01

Many sedimentary basins throughout the world exhibit areas with abnormal pore-fluid pressures (higher or lower than normal or hydrostatic pressure). Predicting pore pressure and other parameters (depth, extension, magnitude, etc.) in such areas are challenging tasks. The compressional acoustic (sonic) log (DT) is often used as a predictor because it responds to changes in porosity or compaction produced by abnormal pore-fluid pressures. Unfortunately, the sonic log is not commonly recorded in most oil and/or gas wells. We propose using an artificial neural network to synthesize sonic logs by identifying the mathematical dependency between DT and the commonly available logs, such as normalized gamma ray (GR) and deep resistivity logs (REID). The artificial neural network process can be divided into three steps: (1) Supervised training of the neural network; (2) confirmation and validation of the model by blind-testing the results in wells that contain both the predictor (GR, REID) and the target values (DT) used in the supervised training; and 3) applying the predictive model to all wells containing the required predictor data and verifying the accuracy of the synthetic DT data by comparing the back-predicted synthetic predictor curves (GRNN, REIDNN) to the recorded predictor curves used in training (GR, REID). Artificial neural networks offer significant advantages over traditional deterministic methods. They do not require a precise mathematical model equation that describes the dependency between the predictor values and the target values and, unlike linear regression techniques, neural network methods do not overpredict mean values and thereby preserve original data variability. One of their most important advantages is that their predictions can be validated and confirmed through back-prediction of the input data. This procedure was applied to predict the presence of overpressured zones in the Anadarko Basin, Oklahoma. The results are promising and encouraging.

A Novel Closed-Head Model of Mild Traumatic Brain Injury Caused by Primary Overpressure Blast to the Cranium Produces Sustained Emotional Deficits in Mice

PubMed Central

Heldt, Scott A.; Elberger, Andrea J.; Deng, Yunping; Guley, Natalie H.; Del Mar, Nobel; Rogers, Joshua; Choi, Gy Won; Ferrell, Jessica; Rex, Tonia S.; Honig, Marcia G.; Reiner, Anton

2014-01-01

Emotional disorders are a common outcome from mild traumatic brain injury (TBI) in humans, but their pathophysiological basis is poorly understood. We have developed a mouse model of closed-head blast injury using an air pressure wave delivered to a small area on one side of the cranium, to create mild TBI. We found that 20-psi blasts in 3-month-old C57BL/6 male mice yielded no obvious behavioral or histological evidence of brain injury, while 25–40 psi blasts produced transient anxiety in an open field arena but little histological evidence of brain damage. By contrast, 50–60 psi blasts resulted in anxiety-like behavior in an open field arena that became more evident with time after blast. In additional behavioral tests conducted 2–8 weeks after blast, 50–60 psi mice also demonstrated increased acoustic startle, perseverance of learned fear, and enhanced contextual fear, as well as depression-like behavior and diminished prepulse inhibition. We found no evident cerebral pathology, but did observe scattered axonal degeneration in brain sections from 50 to 60 psi mice 3–8 weeks after blast. Thus, the TBI caused by single 50–60 psi blasts in mice exhibits the minimal neuronal loss coupled to “diffuse” axonal injury characteristic of human mild TBI. A reduction in the abundance of a subpopulation of excitatory projection neurons in basolateral amygdala enriched in Thy1 was, however, observed. The reported link of this neuronal population to fear suppression suggests their damage by mild TBI may contribute to the heightened anxiety and fearfulness observed after blast in our mice. Our overpressure air blast model of concussion in mice will enable further studies of the mechanisms underlying the diverse emotional deficits seen after mild TBI. PMID:24478749

Underexpanded Supersonic Plume Surface Interactions: Applications for Spacecraft Landings on Planetary Bodies

NASA Technical Reports Server (NTRS)

Mehta, M.; Sengupta, A.; Renno, N. O.; Norman, J. W.; Gulick, D. S.

2011-01-01

Numerical and experimental investigations of both far-field and near-field supersonic steady jet interactions with a flat surface at various atmospheric pressures are presented in this paper. These studies were done in assessing the landing hazards of both the NASA Mars Science Laboratory and Phoenix Mars spacecrafts. Temporal and spatial ground pressure measurements in conjunction with numerical solutions at altitudes of approx.35 nozzle exit diameters and jet expansion ratios (e) between 0.02 and 100 are used. Data from steady nitrogen jets are compared to both pulsed jets and rocket exhaust plumes at Mach approx.5. Due to engine cycling, overpressures and the plate shock dynamics are different between pulsed and steady supersonic impinging jets. In contrast to highly over-expanded (e <1) and underexpanded exhaust plumes, results show that there is a relative ground pressure load maximum for moderately underexpanded (e approx.2-5) jets which demonstrate a long collimated plume shock structure. For plumes with e much >5 (lunar atmospheric regime), the ground pressure is minimal due to the development of a highly expansive shock structure. We show this is dependent on the stability of the plate shock, the length of the supersonic core and plume decay due to shear layer instability which are all a function of the jet expansion ratio. Asymmetry and large gradients in the spatial ground pressure profile and large transient overpressures are predominantly linked to the dynamics of the plate shock. More importantly, this study shows that thruster plumes exhausting into martian environments possess the largest surface pressure loads and can occur at high spacecraft altitudes in contrast to the jet interactions at terrestrial and lunar atmospheres. Theoretical and analytical results also show that subscale supersonic cold gas jets adequately simulate the flow field and loads due to rocket plume impingement provided important scaling parameters are in agreement. These studies indicate the critical importance of testing and modeling plume-surface interactions for descent and ascent of spacecraft and launch vehicles.

The mixed-mode bending method for delamination testing

NASA Technical Reports Server (NTRS)

Reeder, James R.; Crews, John H., Jr.

1989-01-01

A mixed-mode bending (MMB) test procedure is presented which combines double cantilever beam mode-I loading and end-notch flexure mode II loading on a split, unidirectional laminate. The MMB test has been analyzed by FEM and by beam theory in order to ascertain the mode I and mode II components' respective strain energy release rates, G(I) and G(II); these analyses indicate that a wide range of G(I)/G(II) ratios can be generated by varying the applied load's position on the loading lever. The MMB specimen analysis and test procedures are demonstrated for the case of AS4/PEEK unidirectional laminates.

Thermal vacuum chamber repressurization with instrument purging

NASA Astrophysics Data System (ADS)

Woronowicz, Michael S.

2016-09-01

At the conclusion of cryogenic vacuum testing of the James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (JWST-OTIS) in NASA Johnson Space Center's (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are postulating that chamber particulate material stirred up by the repressurization process may be kept from falling into the Integrated Science Instrument Module (ISIM) interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This manuscript describes development of a series of models designed to describe this process. The models are strung together in tandem with a fictitious set of conditions to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

Understanding sources of uncertainty and bias error in models of human response to low amplitude sonic booms

NASA Astrophysics Data System (ADS)

Collmar, M.; Cook, B. G.; Cowart, R.; Freund, D.; Gavin, J.

2015-10-01

A pool of 240 subjects was exposed to a library of waveforms consisting of example signatures of low boom aircraft. The signature library included intentional variations in both loudness and spectral content, and were auralized using the Gulfstream SASS-II sonic boom simulator. Post-processing was used to quantify the impacts of test design decisions on the "quality" of the resultant database. Specific lessons learned from this study include insight regarding potential for bias error due to variations in loudness or peak over-pressure, sources of uncertainty and their relative importance on objective measurements and robustness of individual metrics to wide variations in spectral content. Results provide clear guidance for design of future large scale community surveys, where one must optimize the complex tradeoffs between the size of the surveyed population, spatial footprint of those participants, and the fidelity/density of objective measurements.

Statistical Characterization of Environmental Error Sources Affecting Electronically Scanned Pressure Transducers

NASA Technical Reports Server (NTRS)

Green, Del L.; Walker, Eric L.; Everhart, Joel L.

2006-01-01

Minimization of uncertainty is essential to extend the usable range of the 15-psid Electronically Scanned Pressure [ESP) transducer measurements to the low free-stream static pressures found in hypersonic wind tunnels. Statistical characterization of environmental error sources inducing much of this uncertainty requires a well defined and controlled calibration method. Employing such a controlled calibration system, several studies were conducted that provide quantitative information detailing the required controls needed to minimize environmental and human induced error sources. Results of temperature, environmental pressure, over-pressurization, and set point randomization studies for the 15-psid transducers are presented along with a comparison of two regression methods using data acquired with both 0.36-psid and 15-psid transducers. Together these results provide insight into procedural and environmental controls required for long term high-accuracy pressure measurements near 0.01 psia in the hypersonic testing environment using 15-psid ESP transducers.

Statistical Characterization of Environmental Error Sources Affecting Electronically Scanned Pressure Transducers

NASA Technical Reports Server (NTRS)

Green, Del L.; Walker, Eric L.; Everhart, Joel L.

2006-01-01

Minimization of uncertainty is essential to extend the usable range of the 15-psid Electronically Scanned Pressure (ESP) transducer measurements to the low free-stream static pressures found in hypersonic wind tunnels. Statistical characterization of environmental error sources inducing much of this uncertainty requires a well defined and controlled calibration method. Employing such a controlled calibration system, several studies were conducted that provide quantitative information detailing the required controls needed to minimize environmental and human induced error sources. Results of temperature, environmental pressure, over-pressurization, and set point randomization studies for the 15-psid transducers are presented along with a comparison of two regression methods using data acquired with both 0.36-psid and 15-psid transducers. Together these results provide insight into procedural and environmental controls required for long term high-accuracy pressure measurements near 0.01 psia in the hypersonic testing environment using 15-psid ESP transducers.

Thermal Vacuum Chamber Repressurization with Instrument Purging

NASA Technical Reports Server (NTRS)

Woronowicz, Michael S.

2014-01-01

At the conclusion of cryogenic vacuum testing of the James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (JWST-OTIS) in NASA Johnson Space Center’s (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are postulating that chamber particulate material stirred up by the repressurization process may be kept from falling into the Integrated Science Instrument Module (ISIM) interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This manuscript describes development of a series of models designed to describe this process. The models are strung together in tandem with a fictitious set of conditions to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

On the formation of Friedlander waves in a compressed-gas-driven shock tube

PubMed Central

Tasissa, Abiy F.; Hautefeuille, Martin; Fitek, John H.; Radovitzky, Raúl A.

2016-01-01

Compressed-gas-driven shock tubes have become popular as a laboratory-scale replacement for field blast tests. The well-known initial structure of the Riemann problem eventually evolves into a shock structure thought to resemble a Friedlander wave, although this remains to be demonstrated theoretically. In this paper, we develop a semi-analytical model to predict the key characteristics of pseudo blast waves forming in a shock tube: location where the wave first forms, peak over-pressure, decay time and impulse. The approach is based on combining the solutions of the two different types of wave interactions that arise in the shock tube after the family of rarefaction waves in the Riemann solution interacts with the closed end of the tube. The results of the analytical model are verified against numerical simulations obtained with a finite volume method. The model furnishes a rational approach to relate shock tube parameters to desired blast wave characteristics, and thus constitutes a useful tool for the design of shock tubes for blast testing. PMID:27118888

Effects of UGTs on the ionosphere

NASA Astrophysics Data System (ADS)

Argo, P. E.; Fitzgerald, T. J.

The processes that propagate local effects of underground nuclear tests from the ground into the upper atmosphere, and produce a detectable signal in the ionosphere are described. Initially, the blast wave from a underground test (UGT) radially expands, until it reaches the surface of the earth. The wave is both reflected and transmitted at this sharp discontinuity in propagation media. Tne reflected wave combines with the incident wave to form an 'Airy surface,' at which very strong ripping forces tear the earth apart. This broken region is called the 'spat zone,' and is launched into ballistic motion. The resultant ground motion launches an acoustical wave into the atmosphere. This acoustic wave, with overpressures of a few tenths of one percent, propagates upwards at the speed of sound. Assuming purely linear propagation, the path of the acoustic energy can be tracked using raytracing models. Most of the wave energy, which is radiated nearly vertically, tends to propagate into the upper atmosphere, while wave energy radiated at angles greater than about 30 degrees to the vertical will be reflected back to earth and is probably what is seen by most infrasonde measurements.

Summary of Rocketdyne Engine A5 Rocket Based Combined Cycle Testing

NASA Technical Reports Server (NTRS)

Ketchum. A.; Emanuel, Mark; Cramer, John

1998-01-01

Rocketdyne Propulsion and Power (RPP) has completed a highly successful experimental test program of an advanced rocket based combined cycle (RBCC) propulsion system. The test program was conducted as part of the Advanced Reusable Technology program directed by NASA-MSFC to demonstrate technologies for low-cost access to space. Testing was conducted in the new GASL Flight Acceleration Simulation Test (FAST) facility at sea level (Mach 0), Mach 3.0 - 4.0, and vacuum flight conditions. Significant achievements obtained during the test program include 1) demonstration of engine operation in air-augmented rocket mode (AAR), ramjet mode and rocket mode and 2) smooth transition from AAR to ramjet mode operation. Testing in the fourth mode (scramjet) is scheduled for November 1998.

Assessment of theory of mind in children with communication disorders: role of presentation mode.

PubMed

van Buijsen, Marit; Hendriks, Angelique; Ketelaars, Mieke; Verhoeven, Ludo

2011-01-01

Children with communication disorders have problems with both language and social interaction. The theory-of-mind hypothesis provides an explanation for these problems, and different tests have been developed to test this hypothesis. However, different modes of presentation are used in these tasks, which make the results difficult to compare. In the present study, the performances of typically developing children, children with specific language impairments, and children with autism spectrum disorders were therefore compared using three theory-of-mind tests (the Charlie test, the Smarties test, and the Sally-and-Anne test) presented in three different manners each (spoken, video, and line drawing modes). The results showed differential outcomes for the three types of tests and a significant interaction between group of children and mode of presentation. For the typically developing children, no differential effects of presentation mode were detected. For the children with SLI, the highest test scores were consistently evidenced in the line-drawing mode. For the children with ASD, test performance depended on the mode of presentation. Just how the children's non-verbal age, verbal age, and short-term memory related to their test scores was also explored for each group of children. The test scores of the SLI group correlated significantly with their short-term memory, those of the ASD group with their verbal age. These findings demonstrate that performance on theory-of-mind tests clearly depend upon mode of test presentation as well as the children's cognitive and linguistic abilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

A reduced order, test verified component mode synthesis approach for system modeling applications

NASA Astrophysics Data System (ADS)

Butland, Adam; Avitabile, Peter

2010-05-01

Component mode synthesis (CMS) is a very common approach used for the generation of large system models. In general, these modeling techniques can be separated into two categories: those utilizing a combination of constraint modes and fixed interface normal modes and those based on a combination of free interface normal modes and residual flexibility terms. The major limitation of the methods utilizing constraint modes and fixed interface normal modes is the inability to easily obtain the required information from testing; the result of this limitation is that constraint mode-based techniques are primarily used with numerical models. An alternate approach is proposed which utilizes frequency and shape information acquired from modal testing to update reduced order finite element models using exact analytical model improvement techniques. The connection degrees of freedom are then rigidly constrained in the test verified, reduced order model to provide the boundary conditions necessary for constraint modes and fixed interface normal modes. The CMS approach is then used with this test verified, reduced order model to generate the system model for further analysis. A laboratory structure is used to show the application of the technique with both numerical and simulated experimental components to describe the system and validate the proposed approach. Actual test data is then used in the approach proposed. Due to typical measurement data contaminants that are always included in any test, the measured data is further processed to remove contaminants and is then used in the proposed approach. The final case using improved data with the reduced order, test verified components is shown to produce very acceptable results from the Craig-Bampton component mode synthesis approach. Use of the technique with its strengths and weaknesses are discussed.

Validation and Simulation of Ares I Scale Model Acoustic Test - 3 - Modeling and Evaluating the Effect of Rainbird Water Deluge Inclusion

NASA Technical Reports Server (NTRS)

Strutzenberg, Louise L.; Putman, Gabriel C.

2011-01-01

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. Building on dry simulations of the ASMAT tests with the vehicle at 5 ft. elevation (100 ft. real vehicle elevation), wet simulations of the ASMAT test setup have been performed using the Loci/CHEM computational fluid dynamics software to explore the effect of rainbird water suppression inclusion on the launch platform deck. Two-phase water simulation has been performed using an energy and mass coupled lagrangian particle system module where liquid phase emissions are segregated into clouds of virtual particles and gas phase mass transfer is accomplished through simple Weber number controlled breakup and boiling models. Comparisons have been performed to the dry 5 ft. elevation cases, using configurations with and without launch mounts. These cases have been used to explore the interaction between rainbird spray patterns and launch mount geometry and evaluate the acoustic sound pressure level knockdown achieved through above-deck rainbird deluge inclusion. This comparison has been anchored with validation from live-fire test data which showed a reduction in rainbird effectiveness with the presence of a launch mount.

Controlling the stoichiometry and doping of semiconductor materials

DOEpatents

Albin, David; Burst, James; Metzger, Wyatt; Duenow, Joel; Farrell, Stuart; Colegrove, Eric

2016-08-16

Methods for treating a semiconductor material are provided. According to an aspect of the invention, the method includes annealing the semiconductor material in the presence of a compound that includes a first element and a second element. The first element provides an overpressure to achieve a desired stoichiometry of the semiconductor material, and the second element provides a dopant to the semiconductor material.

33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... maximum transfer rate determined at the pre-transfer conference required by § 156.120(w) of this chapter... section or a lower pressure agreed upon at the pre-transfer conference required by § 156.120(w) of this... paragraph (b) of this section or a higher pressure agreed upon at the pre-transfer conference required by...

33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... maximum transfer rate determined at the pre-transfer conference required by § 156.120(w) of this chapter... section or a lower pressure agreed upon at the pre-transfer conference required by § 156.120(w) of this... paragraph (b) of this section or a higher pressure agreed upon at the pre-transfer conference required by...

33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... maximum transfer rate determined at the pre-transfer conference required by § 156.120(w) of this chapter... section or a lower pressure agreed upon at the pre-transfer conference required by § 156.120(w) of this... paragraph (b) of this section or a higher pressure agreed upon at the pre-transfer conference required by...

Natural circulating passive cooling system for nuclear reactor containment structure

DOEpatents

Gou, Perng-Fei; Wade, Gentry E.

1990-01-01

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

Brain Vulnerability to Repeated Blast Overpressure and Polytrauma

DTIC Science & Technology

2013-11-01

phosphatase in the etiology of tauopathy and chronic traumatic encephalopathy . National Capital Region Traumatic Brain Injury Research Symposium... encephalopathy after traumatic brain injury. USUHS Research Day held at Bethesda, MD – May 13, 2013 7 CONCLUSION As the result of substantial...and countermeasures to lessen short-term impairments as well as chronic debilitation (e.g. chronic traumatic encephalopathy ). 8 Fig 1. BOP

Solvent Recycling for Shipyards

DTIC Science & Technology

1993-05-01

Suvey results are included in Section 5) Survey manufacturers and compile information on available equipment and features . (Data is summarized in Section...should be placed on safety features . Important safety features include explosion-proof electricals and grounding protection, overpressure relief valves...solvent can dissolve a polymer plastic liner, or extract water from a clay liner, resulting in liner leakage. The threat is compounded by the ability

Wireless device for activation of an underground shock wave absorber

NASA Astrophysics Data System (ADS)

Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.

2011-10-01

The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave

PubMed Central

Niwa, Katsuki; Mizutari, Kunio; Matsui, Toshiyasu; Kurioka, Takaomi; Matsunobu, Takeshi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro; Kobayashi, Yasushi

2016-01-01

The ear is the organ that is most sensitive to blast overpressure, and ear damage is most frequently seen after blast exposure. Blast overpressure to the ear results in sensorineural hearing loss, which is untreatable and is often associated with a decline in the quality of life. In this study, we used a rat model to demonstrate the pathophysiological and structural changes in the inner ear that replicate pure sensorineural hearing loss associated with blast injury using laser-induced shock wave (LISW) without any conductive hearing loss. Our results indicate that threshold elevation of the auditory brainstem response (ABR) after blast exposure was primarily caused by outer hair cell dysfunction induced by stereociliary bundle disruption. The bundle disruption pattern was unique; disturbed stereocilia were mostly observed in the outermost row, whereas those in the inner and middle rows stereocilia remained intact. In addition, the ABR examination showed a reduction in wave I amplitude without elevation of the threshold in the lower energy exposure group. This phenomenon was caused by loss of the synaptic ribbon. This type of hearing dysfunction has recently been described as hidden hearing loss caused by cochlear neuropathy, which is associated with tinnitus or hyperacusis. PMID:27531021

Temporal and Spatial Effects of Blast Overpressure on Blood-Brain Barrier Permeability in Traumatic Brain Injury.

PubMed

Kuriakose, Matthew; Rama Rao, Kakulavarapu V; Younger, Daniel; Chandra, Namas

2018-06-06

Blast-induced traumatic brain injury (bTBI) is a "signature wound" in soldiers during training and in combat and has also become a major cause of morbidity in civilians due to increased insurgency. This work examines the role of blood-brain barrier (BBB) disruption as a result of both primary biomechanical and secondary biochemical injury mechanisms in bTBI. Extravasation of sodium fluorescein (NaF) and Evans blue (EB) tracers were used to demonstrate that compromise of the BBB occurs immediately following shock loading, increases in intensity up to 4 hours and returns back to normal in 24 hours. This BBB compromise occurs in multiple regions of the brain in the anterior-posterior direction of the shock wave, with maximum extravasation seen in the frontal cortex. Compromise of the BBB is confirmed by (a) extravasation of tracers into the brain, (b) quantification of tight-junction proteins (TJPs) in the brain and the blood, and (c) tracking specific blood-borne molecules into the brain and brain-specific proteins into the blood. Taken together, this work demonstrates that the BBB compromise occurs as a part of initial biomechanical loading and is a function of increasing blast overpressures.

Dependence of the subharmonic signal from contrast agent microbubbles on ambient pressure: A theoretical analysis.

PubMed

Jiménez-Fernández, J

2018-01-01

This paper investigates the dependence of the subharmonic response in a signal scattered by contrast agent microbubbles on ambient pressure to provide quantitative estimations of local blood pressure. The problem is formulated by assuming a gas bubble encapsulated by a shell of finite thickness with dynamic behavior modeled by a nonlinear viscoelastic constitutive equation. For ambient overpressure compatible with the clinical range, the acoustic pressure intervals where the subharmonic signal may be detected (above the threshold for the onset and below the limit value for the first chaotic transition) are determined. The analysis shows that as the overpressure is increased, all harmonic components are displaced to higher frequencies. This displacement is significant for the subharmonic of order 1/2 and explains the increase or decrease in the subharmonic amplitude with ambient pressure described in previous works. Thus, some questions related to the monotonic dependence of the subharmonic amplitude on ambient pressure are clarified. For different acoustic pressures, quantitative conditions for determining the intervals where the subharmonic amplitude is a monotonic or non-monotonic function of the ambient pressure are provided. Finally, the influence of the ambient pressure on the subharmonic resonance frequency is analyzed.

Impact of reduced near-field entrainment of overpressured volcanic jets on plume development

USGS Publications Warehouse

Saffaraval, Farhad; Solovitz, Stephen A.; Ogden, Darcy E.; Mastin, Larry G.

2012-01-01

Volcanic plumes are often studied using one-dimensional analytical models, which use an empirical entrainment ratio to close the equations. Although this ratio is typically treated as constant, its value near the vent is significantly reduced due to flow development and overpressured conditions. To improve the accuracy of these models, a series of experiments was performed using particle image velocimetry, a high-accuracy, full-field velocity measurement technique. Experiments considered a high-speed jet with Reynolds numbers up to 467,000 and exit pressures up to 2.93 times atmospheric. Exit gas densities were also varied from 0.18 to 1.4 times that of air. The measured velocity was integrated to determine entrainment directly. For jets with exit pressures near atmospheric, entrainment was approximately 30% less than the fully developed level at 20 diameters from the exit. At pressures nearly three times that of the atmosphere, entrainment was 60% less. These results were introduced into Plumeria, a one-dimensional plume model, to examine the impact of reduced entrainment. The maximum column height was only slightly modified, but the critical radius for collapse was significantly reduced, decreasing by nearly a factor of two at moderate eruptive pressures.

An earthquake mechanism based on rapid sealing of faults

USGS Publications Warehouse

Blanpied, M.L.; Lockner, D.A.; Byerlee, J.D.

1992-01-01

RECENT seismological, heat flow and stress measurements in active fault zones such as the San Andreas have led to the suggestion1,2 that such zones can be relatively weak. One explanation for this may be the presence of overpressured fluids along the fault3-5, which would reduce the shear stress required for sliding by partially 'floating' the rock. Although several mechanisms have been proposed for overpressurizing fault fluids3,4,6,7, we recall that 'pressure seals' are known to form in both sedimentary8 and igneous9 rocks by the redistribution of materials in solution; the formation of such a seal along the boundaries of a fault will prevent the communication of fluids between the porous, deforming fault zone and the surrounding country rock. Compaction of fault gouge, under hydrostatic loading and/or during shear, elevates pore pressure in the sealed fault and allows sliding at low shear stress. We report the results of laboratory sliding experiments on granite, which demonstrate that the sliding resistance of faults can be significantly decreased by sealing and compaction. The weakening that results from shear-induced compaction can be rapid, and may provide an instability mechanism for earthquakes.

Very-high thermal and electrical conductivity in overpressure-processed Bi2Sr2CaCu2O8+x wires

NASA Astrophysics Data System (ADS)

Bonura, M.; Avitabile, F.; Barth, C.; Jiang, J.; Larbalestier, D.; Fête, A.; Leo, A.; Bottura, L.; Senatore, C.

2018-05-01

The residual-resistivity ratio (RRR) of the normal-metal matrix is a key parameter for the electrical and thermal stability of technical superconductors. In Bi2Sr2CaCu2 {{{O}}}8+x (Bi-2212) round wires, the precursor powders are embedded in a Ag matrix without any diffusion barrier, and elemental diffusion from the superconducting filaments into the Ag might be expected to contaminate the matrix during the melt processing required for high critical current density development. This work shows that the overpressure processing, which is adopted to enhance the critical current performance, improves the thermal and electrical conductivities of the conductor, too. In the case of wires reacted with a standard processing performed in 1 bar O2, the RRR of the Ag matrix is about 90, in spite of the simple conductor design that does not include diffusion barriers. Increasing the total reaction pressure to 100 bar improves the RRR to about 200. The differences in RRR reflect on the thermal conductivity of the whole conductor, which has been investigated in magnetic fields up to 19 T.

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

PubMed

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

2015-11-01

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

Growth and Properties of Lattice Matched GaAsSbN Epilayer on GaAs for Solar Cell Applications

NASA Technical Reports Server (NTRS)

Bharatan, Sudhakar; Iyer, Shanthi; Matney, Kevin; Collis, Ward J.; Nunna Kalyan; Li, Jia; Wu, Liangjin; McGuire, Kristopher; McNeil, Laurie E.

2006-01-01

The growth and properties of GaAsSbN single quantum wells (SQWs) are investigated in this work. The heterostructures were grown on GaAs substrates in an elemental solid source molecular beam epitaxy (MBE) system assisted with a RF plasma nitrogen source. A systematic study has been carried out to determine the influence of various growth conditions, such as the growth temperature and the source shutter-opening sequence, on the quality of the grown layers and the incorporation of N and Sb. The effects of ex situ and in situ annealing under As overpressure on the optical properties of the layers have also been investigated. Substrate temperature in the range of 450-470 C was found to be optimum. Simultaneous opening of the source shutters was found to yield sharper QW interfaces. N and Sb incorporations were found to depend strongly upon substrate temperatures and source shutter opening sequences. A significant increase in PL intensity with a narrowing of PL line shape and blue shift in emission energy were observed on annealing the GaAsSbN/GaAs SQW, with in situ annealing under As overpressure providing better results, compared to ex situ annealing.

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave.

PubMed

Niwa, Katsuki; Mizutari, Kunio; Matsui, Toshiyasu; Kurioka, Takaomi; Matsunobu, Takeshi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro; Kobayashi, Yasushi

2016-08-17

The ear is the organ that is most sensitive to blast overpressure, and ear damage is most frequently seen after blast exposure. Blast overpressure to the ear results in sensorineural hearing loss, which is untreatable and is often associated with a decline in the quality of life. In this study, we used a rat model to demonstrate the pathophysiological and structural changes in the inner ear that replicate pure sensorineural hearing loss associated with blast injury using laser-induced shock wave (LISW) without any conductive hearing loss. Our results indicate that threshold elevation of the auditory brainstem response (ABR) after blast exposure was primarily caused by outer hair cell dysfunction induced by stereociliary bundle disruption. The bundle disruption pattern was unique; disturbed stereocilia were mostly observed in the outermost row, whereas those in the inner and middle rows stereocilia remained intact. In addition, the ABR examination showed a reduction in wave I amplitude without elevation of the threshold in the lower energy exposure group. This phenomenon was caused by loss of the synaptic ribbon. This type of hearing dysfunction has recently been described as hidden hearing loss caused by cochlear neuropathy, which is associated with tinnitus or hyperacusis.

Effect of crustal heterogeneities and effective rock strength on the formation of HP and UHP rocks.

NASA Astrophysics Data System (ADS)

Reuber, Georg; Kaus, Boris; Schmalholz, Stefan; White, Richard

2015-04-01

The formation of high pressure and ultra-high pressure rocks has been controversially discussed in recent years. Most existing petrological interpretations assume that pressure in the Earth is lithostatic and therefore HP and UHP rocks have to come from great depth, which usually involves going down a subduction channel and being exhumed again. Yet, an alternative explanation points out that pressure in the lithosphere is often non-lithostatic and can be either smaller or larger than lithostatic as a function of location and time. Whether this effect is tectonically significant or not depends on the magnitude of non-lithostatic pressure, and as a result a number of researchers have recently performed numerical simulations to address this. Somewhat disturbingly, they obtained widely differing results with some claiming that overpressures as large as a GPa can occur (Schmalholz et al. 2014), whereas others show that overpressures of exhumed rocks are generally less than 20% and thus insignificant (Li et al. 2010; Burov et al. 2014). In order to understand where these discrepancies come from, we reproduce the simulations of Li et al (2010) of a typical subduction and collision scenario, using an independently developed numerical code (MVEP2). For the same model setup and parameters, we confirm the earlier results of Li et al. (2010) and obtain no more than ~20% overpressure in exhumed rocks of the subduction channel. Yet, a critical assumption in their models is that the subducted crust is laterally homogeneous and that it has a low effective friction angle that is less than 7o. The friction angle of (dry) rocks is experimentally well-constrained to be around 30o, and low effective friction angles require, for example, high-fluid pressures. Whereas high fluid pressures might exist in the sediment-rich upper crust, they are likely to be much lower or absent in the lower crust from which melt has been extracted or in rocks that underwent a previous orogenic cycle. In a next step, we performed several hundred numerical simulations to understand the effects of km-scale heterogeneities and material parameters on pressure magnitudes, using a model setup that is otherwise very similar to the one of Li et al. (2010). Results show that significant non-lithostatic pressures occur if (lower) crustal rocks are dry or if km-scale (nappe-sized) heterogeneities with dryer rocks are present within the crust. Overpressure magnitudes can be up to 1 GPa or 100% and in some cases rock assemblages are temporarily in the coesite stability field at a depth of only 40 km, followed by rapid exhumation to the surface. Tectonic overpressures can vary strongly in magnitude versus time, but peak pressures are present sufficiently long for metamorphic reactions to occur. The presence of heterogeneities can affect the crustal-scaled deformation pattern, and the effective friction angle of crustal-scale rocks (or the dryness of these rocks) is a key parameter that determines the magnitude of non-lithostatic pressures. Our results thus reconcile previous findings and highlight the importance of having an accurate knowledge of the fluid-pressure, initial crustal structure and rock composition during continental collision. If rocks are dry by the time they enter a subduction zone, or are stronger/dryer than surrounding rocks, they are likely to develop significantly higher pressures than nearby rocks. This might explain the puzzling observation that some nappes have very high peak pressures, while juxtaposed nappes have much lower values, without clear structural evidence for deep burial and exhumation along a subduction channel of the high-pressure nappe. Our models might also give a partial explanation of why the reported timescales for high and ultra-high pressure stages of peak metamorphism are often very short. References: Burov, E., Francois, T., Agard, P., Le Pourhiet, L., Meyer, B., Tirel, C., Lebedev, S., Yamato, P., Brun, J.-P., 2014. Tectonophysics. Tectonophysics 631, 212-250. doi:10.1016/j.tecto.2014.04.033 Li, Z.H., Gerya, T.V., Burg, J.-P., 2010. Influence of tectonic overpressure on P-T paths of HP-UHP rocks in continental collision zones: thermomechanical modelling. J Metamorph Geol 28, 227-247. doi:10.1111/j.1525-1314.2009.00864.x Schmalholz, S.M., Duretz, T., Schenker, F.L., Podladchikov, Y.Y., 2014. Tectonophysics. Tectonophysics 631, 160-175. doi:10.1016/j.tecto.2014.05.018

Solid Rocket Launch Vehicle Explosion Environments

NASA Technical Reports Server (NTRS)

Richardson, E. H.; Blackwood, J. M.; Hays, M. J.; Skinner, T.

2014-01-01

Empirical explosion data from full scale solid rocket launch vehicle accidents and tests were collected from all available literature from the 1950s to the present. In general data included peak blast overpressure, blast impulse, fragment size, fragment speed, and fragment dispersion. Most propellants were 1.1 explosives but a few were 1.3. Oftentimes the data from a single accident was disjointed and/or missing key aspects. Despite this fact, once the data as a whole was digitized, categorized, and plotted clear trends appeared. Particular emphasis was placed on tests or accidents that would be applicable to scenarios from which a crew might need to escape. Therefore, such tests where a large quantity of high explosive was used to initiate the solid rocket explosion were differentiated. Also, high speed ground impacts or tests used to simulate such were also culled. It was found that the explosions from all accidents and applicable tests could be described using only the pressurized gas energy stored in the chamber at the time of failure. Additionally, fragmentation trends were produced. Only one accident mentioned the elusive "small" propellant fragments, but upon further analysis it was found that these were most likely produced as secondary fragments when larger primary fragments impacted the ground. Finally, a brief discussion of how this data is used in a new launch vehicle explosion model for improving crew/payload survival is presented.

A Monte Carlo Approach to Modeling the Breakup of the Space Launch System EM-1 Core Stage with an Integrated Blast and Fragment Catalogue

NASA Technical Reports Server (NTRS)

Richardson, Erin; Hays, M. J.; Blackwood, J. M.; Skinner, T.

2014-01-01

The Liquid Propellant Fragment Overpressure Acceleration Model (L-FOAM) is a tool developed by Bangham Engineering Incorporated (BEi) that produces a representative debris cloud from an exploding liquid-propellant launch vehicle. Here it is applied to the Core Stage (CS) of the National Aeronautics and Space Administration (NASA) Space Launch System (SLS launch vehicle). A combination of Probability Density Functions (PDF) based on empirical data from rocket accidents and applicable tests, as well as SLS specific geometry are combined in a MATLAB script to create unique fragment catalogues each time L-FOAM is run-tailored for a Monte Carlo approach for risk analysis. By accelerating the debris catalogue with the BEi blast model for liquid hydrogen / liquid oxygen explosions, the result is a fully integrated code that models the destruction of the CS at a given point in its trajectory and generates hundreds of individual fragment catalogues with initial imparted velocities. The BEi blast model provides the blast size (radius) and strength (overpressure) as probabilities based on empirical data and anchored with analytical work. The coupling of the L-FOAM catalogue with the BEi blast model is validated with a simulation of the Project PYRO S-IV destruct test. When running a Monte Carlo simulation, L-FOAM can accelerate all catalogues with the same blast (mean blast, 2 s blast, etc.), or vary the blast size and strength based on their respective probabilities. L-FOAM then propagates these fragments until impact with the earth. Results from L-FOAM include a description of each fragment (dimensions, weight, ballistic coefficient, type and initial location on the rocket), imparted velocity from the blast, and impact data depending on user desired application. LFOAM application is for both near-field (fragment impact to escaping crew capsule) and far-field (fragment ground impact footprint) safety considerations. The user is thus able to use statistics from a Monte Carlo set of L-FOAM catalogues to quantify risk for a multitude of potential CS destruct scenarios. Examples include the effect of warning time on the survivability of an escaping crew capsule or the maximum fragment velocities generated by the ignition of leaking propellants in internal cavities.

Characterization of the Edge Crack Torsion (ECT) Test for Mode III Fracture Toughness Measurement of Laminated Composites

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.

2004-01-01

The edge crack torsion (ECT) test is designed to initiate mode III delamination growth in composite laminates. The test has undergone several design changes during its development. The objective of this paper was to determine the suitability of the current ECT test design a mode III fracture test. To this end, ECT tests were conducted on specimens manufactured from IM7/8552 and S2/8552 tape laminates. Three-dimensional finite element analyses were performed. The analysis results were used to calculate the distribution of mode I, mode II, and mode III strain energy release rate along the delamination front. The results indicated that mode IIIdominated delamination growth would be initiated from the specimen center. However, in specimens of both material types, the measured values of GIIIc exhibited significant dependence on delamination length. Load-displacement response of the specimens exhibited significant deviation from linearity before specimen failure. X-radiographs of a sample of specimens revealed that damage was initiated in the specimens prior to failure. Further inspection of the failure surfaces is required to identify the damage and determine that mode III delamination is initiated in the specimens.

Dual throat thruster cold flow analysis

NASA Technical Reports Server (NTRS)

Lundgreen, R. B.; Nickerson, G. R.; Obrien, C. J.

1978-01-01

The concept was evaluated with cold flow (nitrogen gas) testing and through analysis for application as a tripropellant engine for single-stage-to-orbit type missions. Three modes of operation were tested and analyzed: (1) Mode 1 Series Burn, (2) Mode 1 Parallel Burn, and (3) Mode 2. Primary emphasis was placed on the Mode 2 plume attachment aerodynamics and performance. The conclusions from the test data analysis are as follows: (1) the concept is aerodynamically feasible, (2) the performance loss is as low as 0.5 percent, (3) the loss is minimized by an optimum nozzle spacing corresponding to an AF-ATS ratio of about 1.5 or an Le/Rtp ratio of 3.0 for the dual throat hardware tested, requiring only 4% bleed flow, (4) the Mode 1 and Mode 2 geometry requirements are compatible and pose no significant design problems.

Multicycle rapid thermal annealing optimization of Mg-implanted GaN: Evolution of surface, optical, and structural properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenlee, Jordan D., E-mail: jordan.greenlee.ctr@nrl.navy.mil; Feigelson, Boris N.; Anderson, Travis J.

2014-08-14

The first step of a multi-cycle rapid thermal annealing process was systematically studied. The surface, structure, and optical properties of Mg implanted GaN thin films annealed at temperatures ranging from 900 to 1200 °C were investigated by Raman spectroscopy, photoluminescence, UV-visible spectroscopy, atomic force microscopy, and Nomarski microscopy. The GaN thin films are capped with two layers of in-situ metal organic chemical vapor deposition -grown AlN and annealed in 24 bar of N{sub 2} overpressure to avoid GaN decomposition. The crystal quality of the GaN improves with increasing annealing temperature as confirmed by UV-visible spectroscopy and the full widths at halfmore » maximums of the E{sub 2} and A{sub 1} (LO) Raman modes. The crystal quality of films annealed above 1100 °C exceeds the quality of the as-grown films. At 1200 °C, Mg is optically activated, which is determined by photoluminescence measurements. However, at 1200 °C, the GaN begins to decompose as evidenced by pit formation on the surface of the samples. Therefore, it was determined that the optimal temperature for the first step in a multi-cycle rapid thermal anneal process should be conducted at 1150 °C due to crystal quality and surface morphology considerations.« less

40 CFR 1051.505 - What special provisions apply for testing snowmobiles?

Code of Federal Regulations, 2010 CFR

2010-07-01

... provisions for testing snowmobiles: (a) You may perform steady-state testing with either discrete-mode or... both discrete-mode and ramped-modal testing (either in your original application or in an amendment to... as allowed by the Clean Air Act. Measure steady-state emissions as follows: (1) For discrete-mode...

40 CFR 86.1363-2007 - Steady-state testing with a discrete-mode cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Steady-state testing with a discrete-mode cycle. 86.1363-2007 Section 86.1363-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Exhaust Test Procedures § 86.1363-2007 Steady-state testing with a discrete-mode cycle. This section...

40 CFR 86.335-79 - Gasoline-fueled engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Gasoline-fueled engine test cycle. 86....335-79 Gasoline-fueled engine test cycle. (a) The following test sequence shall be followed in.... Cycle No. Mode No. Mode Observed torque (percent of maximum observed) Time in mode-seconds Cumulative...

40 CFR 1045.505 - How do I test engines using discrete-mode or ramped-modal duty cycles?

Code of Federal Regulations, 2011 CFR

2011-07-01

... your own testing. If you submit certification test data collected with both discrete-mode and ramped...-use operation. (d) For full-load operating modes, operate the engine at wide-open throttle. (e) See 40...

Recent Enhancements to the National Transonic Facility (Mixed Mode Operations)

NASA Technical Reports Server (NTRS)

Kilgore, W. Allen; Chan, David; Balakrishna, S.; Wahls, Richard A.

2006-01-01

The U.S. National Transonic Facility continues to make enhancements to provide quality data in a safe, efficient and cost effective method for aerodynamic ground testing. Recent enhancements discussed in this paper include the development of a Mixed-mode of operations that combine Air-mode operations with Nitrogen-mode operations. This implementation and operational results of this new Mixed-mode expands the ambient temperature transonic region of testing beyond the Air-mode limitations at a significantly reduced cost over Nitrogen Mode operation.

Development of an Accelerated Test Design for Predicting the Service Life of the Solar Array at Mead, Nebraska

NASA Technical Reports Server (NTRS)

Gaines, G. B.; Thomas, R. E.; Noel, G. T.; Shilliday, T. S.; Wood, V. E.; Carmichael, D. C.

1979-01-01

Potential long-term degradation modes for the two types of modules in the Mead array were determined and judgments were made as to those environmental stresses and combinations of stresses which accelerate the degradation of the power output. Hierarchical trees representing the severity of effects of stresses (test conditions) on eleven individual degradation modes were constructed and were pruned of tests judged to be nonessential. Composites of those trees were developed so that there is now one pruned tree covering eight degradation modes, another covering two degradation modes, and a third covering one degradation mode. These three composite trees form the basis for selection of test conditions in the final test plan which is now being prepared.

Learners' choices and beliefs about self-testing.

PubMed

Kornell, Nate; Son, Lisa K

2009-07-01

Students have to make scores of practical decisions when they study. We investigated the effectiveness of, and beliefs underlying, one such practical decision: the decision to test oneself while studying. Using a flashcards-like procedure, participants studied lists of word pairs. On the second of two study trials, participants either saw the entire pair again (pair mode) or saw the cue and attempted to generate the target (test mode). Participants were asked either to rate the effectiveness of each study mode (Experiment 1) or to choose between the two modes (Experiment 2). The results demonstrated a mismatch between metacognitive beliefs and study choices: Participants (incorrectly) judged that the pair mode resulted in the most learning, but chose the test mode most frequently. A post-experimental questionnaire suggested that self-testing was motivated by a desire to diagnose learning rather than a desire to improve learning.

40 CFR 1045.505 - How do I test engines using discrete-mode or ramped-modal duty cycles?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test engines using discrete... MARINE ENGINES AND VESSELS Test Procedures § 1045.505 How do I test engines using discrete-mode or ramped... allow you to perform tests with either discrete-mode or ramped-modal sampling. You must use the modal...

Shake test results of the MDHC test stand in the 40- by 80-foot wind tunnel

NASA Technical Reports Server (NTRS)

Lau, Benton H.; Peterson, Randall

1994-01-01

A shake test was conducted to determine the modal properties of the MDHC (McDonnell Douglas Helicopter Company) test stand installed in the 40- by 80- Foot Wind Tunnel at Ames Research Center. The shake test was conducted for three wind-tunnel balance configurations with and without balance dampers, and with the snubber engagement to lock the balance frame. A hydraulic shaker was used to apply random excitation at the rotor hub in the longitudinal and lateral directions. A GenRad 2515 computer-aided test system computed the frequency response functions at the rotor hub and support struts. From these response functions, the modal properties, including the natural frequency, damping ratio, and mode shape were calculated. The critical modes with low damping ratios are identified as the test-stand second longitudinal mode for the dampers-off configuration, the test-stand yaw mode for the dampers-on configuration, and the test stand first longitudinal mode for the balance-frame locked configuration.

46 CFR 54.15-25 - Minimum relief capacities for cargo tanks containing compressed or liquefied gas.

Code of Federal Regulations, 2012 CFR

2012-10-01

... overpressure permitted shall be in accordance with § 54.15-5. (c) The rate of discharge for heat input of fire... exposure factor for the following tank types: F=1.0 for tanks without insulation located on the open deck. F=0.5 for tanks on the open deck having insulation that has approved fire proofing, thermal...

46 CFR 54.15-25 - Minimum relief capacities for cargo tanks containing compressed or liquefied gas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... overpressure permitted shall be in accordance with § 54.15-5. (c) The rate of discharge for heat input of fire... exposure factor for the following tank types: F=1.0 for tanks without insulation located on the open deck. F=0.5 for tanks on the open deck having insulation that has approved fire proofing, thermal...

46 CFR 54.15-25 - Minimum relief capacities for cargo tanks containing compressed or liquefied gas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... overpressure permitted shall be in accordance with § 54.15-5. (c) The rate of discharge for heat input of fire... exposure factor for the following tank types: F=1.0 for tanks without insulation located on the open deck. F=0.5 for tanks on the open deck having insulation that has approved fire proofing, thermal...

46 CFR 54.15-25 - Minimum relief capacities for cargo tanks containing compressed or liquefied gas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... overpressure permitted shall be in accordance with § 54.15-5. (c) The rate of discharge for heat input of fire... exposure factor for the following tank types: F=1.0 for tanks without insulation located on the open deck. F=0.5 for tanks on the open deck having insulation that has approved fire proofing, thermal...