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Sample records for excavation nuclear detonations

  1. Post detonation nuclear forensics

    SciTech Connect

    Davis, Jay

    2014-05-09

    The problem of working backwards from the debris of a nuclear explosion to attempt to attribute the event to a particular actor is singularly difficult technically. However, moving from physical information of any certainty through the political steps that would lead to national action presents daunting policy questions as well. This monograph will outline the operational and physical components of this problem and suggest the difficulty of the policy questions that remain.

  2. Post detonation nuclear forensics

    NASA Astrophysics Data System (ADS)

    Davis, Jay

    2014-05-01

    The problem of working backwards from the debris of a nuclear explosion to attempt to attribute the event to a particular actor is singularly difficult technically. However, moving from physical information of any certainty through the political steps that would lead to national action presents daunting policy questions as well. This monograph will outline the operational and physical components of this problem and suggest the difficulty of the policy questions that remain.

  3. Radioactive Fallout from Terrorist Nuclear Detonations

    SciTech Connect

    Marrs, R E

    2007-05-03

    Responding correctly during the first hour after a terrorist nuclear detonation is the key to reducing casualties from a low-yield surface burst, and a correct response requires an understanding of the rapidly changing dose rate from fallout. This report provides an empirical formula for dose rate as a function of time and location that can guide the response to an unexpected nuclear detonation. At least one post-detonation radiation measurement is required if the yield and other characteristics of the detonation are unknown.

  4. Reducing the Consequences of a Nuclear Detonation.

    SciTech Connect

    Buddemeier, B R

    2007-11-09

    The 2002 National Strategy to Combat Weapons of Mass Destruction states that 'the United States must be prepared to respond to the use of WMD against our citizens, our military forces, and those of friends and allies'. Scenario No.1 of the 15 Department of Homeland Security national planning scenarios is an improvised nuclear detonation in the national capitol region. An effective response involves managing large-scale incident response, mass casualty, mass evacuation, and mass decontamination issues. Preparedness planning activities based on this scenario provided difficult challenges in time critical decision making and managing a large number of casualties within the hazard area. Perhaps even more challenging is the need to coordinate a large scale response across multiple jurisdictions and effectively responding with limited infrastructure and resources. Federal response planning continues to make improvements in coordination and recommending protective actions, but much work remains. The most critical life-saving activity depends on actions taken in the first few minutes and hours of an event. The most effective way to reduce the enormous national and international social and economic disruptions from a domestic nuclear explosion is through planning and rapid action, from the individual to the federal response. Anticipating response resources for survivors based on predicted types and distributions of injuries needs to be addressed.

  5. The Nuclear Detonation Detection System on the GPS satellites

    SciTech Connect

    Higbie, P.R.; Blocker, N.K.

    1993-07-27

    This article begins with a historical perspective of satellite usage in monitoring nuclear detonations. Current capabilities of the 24 GPS satellites in detecting the light, gamma rays, x-rays and neutrons from a nuclear explosion are described. In particular, an optical radiometer developed at Sandia National Laboratories is characterized. Operational information and calibration procedures are emphasized.

  6. Ground-based Nuclear Detonation Detection (GNDD) Technology Roadmap

    SciTech Connect

    Casey, Leslie A.

    2014-01-13

    This GNDD Technology Roadmap is intended to provide guidance to potential researchers and help management define research priorities to achieve technology advancements for ground-based nuclear explosion monitoring science being pursued by the Ground-based Nuclear Detonation Detection (GNDD) Team within the Office of Nuclear Detonation Detection in the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Four science-based elements were selected to encompass the entire scope of nuclear monitoring research and development (R&D) necessary to facilitate breakthrough scientific results, as well as deliver impactful products. Promising future R&D is delineated including dual use associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Important research themes as well as associated metrics are identified along with a progression of accomplishments, represented by a selected bibliography, that are precursors to major improvements to nuclear explosion monitoring.

  7. Thermal Radiation from Nuclear Detonations in Urban Environments

    SciTech Connect

    Marrs, R E; Moss, W C; Whitlock, B

    2007-06-04

    There are three principal causes of ''prompt'' casualties from a nuclear detonation: nuclear (gamma-ray and neutron) radiation, thermal radiation, and blast. Common estimates of the range of these prompt effects indicate that thermal radiation has the largest lethal range [1]. Non-lethal skin burns, flash blindness, and retinal burns occur out to much greater range. Estimates of casualties from thermal radiation assume air bursts over flat terrain. In urban environments with multiple buildings and terrain features, the extent of thermal radiation may be significantly reduced by shadowing. We have developed a capability for calculating the distribution of thermal energy deposition in urban environments using detailed 3D computer models of actual cities. The size, height, and radiated power from the fireball as a function of time are combined with ray tracing to calculate the energy deposition on all surfaces. For surface bursts less than 100 kt in locations with large buildings or terrain features, the calculations confirm the expected reduction in thermal damage.

  8. Medical lessons learned from chernobyl relative to nuclear detonations and failed nuclear reactors.

    PubMed

    Dallas, Cham E

    2012-12-01

    The Chernobyl disaster in 1986 involved the largest airborne release of radioactivity in history, more than 100 times as much radioactivity as the Hiroshima and Nagasaki atomic bombs together. The resulting emergency response, administrative blunders, and subsequent patient outcomes from this large-scale radiological disaster provide a wealth of information and valuable lessons for those who may find themselves having to deal with the staggering consequences of nuclear war. Research findings, administrative strategies (successful and otherwise), and resulting clinical procedures from the Chernobyl experience are reviewed to determine a current utility in addressing the appropriate protocols for a medical response to nuclear war. As various myths are still widely associated with radiation exposure, attention is given to the realities of a mass casualty medical response as it would occur with a nuclear detonation. PMID:23241462

  9. Russian Military and Security Forces: A Postulated Reaction to a Nuclear Detonation

    SciTech Connect

    Ball, D

    2005-04-29

    In this paper, we will examine how Russia's military and security forces might react to the detonation of a 10-kiloton nuclear weapon placed next to the walls surrounding the Kremlin. At the time of this 'big bang,' Putin is situated outside Moscow and survives the explosion. No one claims responsibility for the detonation. No other information is known. Numerous variables will determine how events ultimately unfold and how the military and security forces will respond. Prior to examining these variables in greater detail, it is imperative to elucidate first what we mean by Russia's military and security forces.

  10. Analysis of sheltering and evacuation strategies for a national capital region nuclear detonation scenario.

    SciTech Connect

    Yoshimura, Ann S.; Brandt, Larry D.

    2011-12-01

    Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kT detonation in the National Capital Region. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternatives at one exemplary point. For most Washington, DC neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.

  11. Analysis of sheltering and evacuation strategies for a Chicago nuclear detonation scenario.

    SciTech Connect

    Yoshimura, Ann S.; Brandt, Larry D.

    2011-09-01

    Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kt detonation in Chicago. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternatives at selected exemplary points. For many Chicago neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.

  12. GIS surface effects archive of underground nuclear detonations conducted at Yucca Flat and Pahute Mesa, Nevada Test Site, Nevada

    SciTech Connect

    Grasso, D.N.

    2001-11-02

    This report presents a new comprehensive, digital archive of more than 40 years of geologic surface effects maps produced at individual detonation sites throughout the Yucca Flat and Pahute Mesa nuclear testing areas of the Nevada Test Site, Nye County, Nevada. The Geographic Information System (GIS) surface effects map archive on CD-ROM (this report) comprehensively documents the surface effects of underground nuclear detonations conducted at two of the most extensively used testing areas of the Nevada Test Site. Between 1951 and 1992, numerous investigators of the U.S. Geological Survey, the Los Alamos National Laboratory, the Lawrence Livermore National Laboratory, and the Defense Threat Reduction Agency meticulously mapped the surface effects caused by underground nuclear testing. Their work documented the effects of more than seventy percent of the underground nuclear detonations conducted at Yucca Flat and all of the underground nuclear detonations conducted at Pahute Mesa.

  13. Allocation of scarce resources after a nuclear detonation: setting the context.

    PubMed

    Knebel, Ann R; Coleman, C Norman; Cliffer, Kenneth D; Murrain-Hill, Paula; McNally, Richard; Oancea, Victor; Jacobs, Jimmie; Buddemeier, Brooke; Hick, John L; Weinstock, David M; Hrdina, Chad M; Taylor, Tammy; Matzo, Marianne; Bader, Judith L; Livinski, Alicia A; Parker, Gerald; Yeskey, Kevin

    2011-03-01

    The purpose of this article is to set the context for this special issue of Disaster Medicine and Public Health Preparedness on the allocation of scarce resources in an improvised nuclear device incident. A nuclear detonation occurs when a sufficient amount of fissile material is brought suddenly together to reach critical mass and cause an explosion. Although the chance of a nuclear detonation is thought to be small, the consequences are potentially catastrophic, so planning for an effective medical response is necessary, albeit complex. A substantial nuclear detonation will result in physical effects and a great number of casualties that will require an organized medical response to save lives. With this type of incident, the demand for resources to treat casualties will far exceed what is available. To meet the goal of providing medical care (including symptomatic/palliative care) with fairness as the underlying ethical principle, planning for allocation of scarce resources among all involved sectors needs to be integrated and practiced. With thoughtful and realistic planning, the medical response in the chaotic environment may be made more effective and efficient for both victims and medical responders. PMID:21402809

  14. Calculated concentrations of any radionuclide deposited on the ground by release from underground nuclear detonations, tests of nuclear rockets, and tests of nuclear ramjet engines

    SciTech Connect

    Hicks, H.G.

    1981-11-01

    This report presents calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from three types of event that deposited detectable radioactivity outside the Nevada Test Site complex, namely, underground nuclear detonations, tests of nuclear rocket engines and tests of nuclear ramjet engines.

  15. Radiation injury after a nuclear detonation: medical consequences and the need for scarce resources allocation.

    PubMed

    DiCarlo, Andrea L; Maher, Carmen; Hick, John L; Hanfling, Dan; Dainiak, Nicholas; Chao, Nelson; Bader, Judith L; Coleman, C Norman; Weinstock, David M

    2011-03-01

    A 10-kiloton (kT) nuclear detonation within a US city could expose hundreds of thousands of people to radiation. The Scarce Resources for a Nuclear Detonation Project was undertaken to guide community planning and response in the aftermath of a nuclear detonation, when demand will greatly exceed available resources. This article reviews the pertinent literature on radiation injuries from human exposures and animal models to provide a foundation for the triage and management approaches outlined in this special issue. Whole-body doses >2 Gy can produce clinically significant acute radiation syndrome (ARS), which classically involves the hematologic, gastrointestinal, cutaneous, and cardiovascular/central nervous systems. The severity and presentation of ARS are affected by several factors, including radiation dose and dose rate, interindividual variability in radiation response, type of radiation (eg, gamma alone, gamma plus neutrons), partial-body shielding, and possibly age, sex, and certain preexisting medical conditions. The combination of radiation with trauma, burns, or both (ie, combined injury) confers a worse prognosis than the same dose of radiation alone. Supportive care measures, including fluid support, antibiotics, and possibly myeloid cytokines (eg, granulocyte colony-stimulating factor), can improve the prognosis for some irradiated casualties. Finally, expert guidance and surge capacity for casualties with ARS are available from the Radiation Emergency Medical Management Web site and the Radiation Injury Treatment Network. PMID:21402810

  16. Radiation Injury After a Nuclear Detonation: Medical Consequences and the Need for Scarce Resources Allocation

    PubMed Central

    DiCarlo, Andrea L.; Maher, Carmen; Hick, John L.; Hanfling, Dan; Dainiak, Nicholas; Chao, Nelson; Bader, Judith L.; Coleman, C. Norman; Weinstock, David M.

    2013-01-01

    A 10-kiloton (kT) nuclear detonation within a US city could expose hundreds of thousands of people to radiation. The Scarce Resources for a Nuclear Detonation Project was undertaken to guide community planning and response in the aftermath of a nuclear detonation, when demand will greatly exceed available resources. This article reviews the pertinent literature on radiation injuries from human exposures and animal models to provide a foundation for the triage and management approaches outlined in this special issue. Whole-body doses >2 Gy can produce clinically significant acute radiation syndrome (ARS), which classically involves the hematologic, gastrointestinal, cutaneous, and cardiovascular/central nervous systems. The severity and presentation of ARS are affected by several factors, including radiation dose and dose rate, interindividual variability in radiation response, type of radiation (eg, gamma alone, gamma plus neutrons), partial-body shielding, and possibly age, sex, and certain preexisting medical conditions. The combination of radiation with trauma, burns, or both (ie, combined injury) confers a worse prognosis than the same dose of radiation alone. Supportive care measures, including fluid support, antibiotics, and possibly myeloid cytokines (eg, granulocyte colony-stimulating factor), can improve the prognosis for some irradiated casualties. Finally, expert guidance and surge capacity for casualties with ARS are available from the Radiation Emergency Medical Management Web site and the Radiation Injury Treatment Network. PMID:21402810

  17. NUclear EVacuation Analysis Code (NUEVAC) : a tool for evaluation of sheltering and evacuation responses following urban nuclear detonations.

    SciTech Connect

    Yoshimura, Ann S.; Brandt, Larry D.

    2009-11-01

    The NUclear EVacuation Analysis Code (NUEVAC) has been developed by Sandia National Laboratories to support the analysis of shelter-evacuate (S-E) strategies following an urban nuclear detonation. This tool can model a range of behaviors, including complex evacuation timing and path selection, as well as various sheltering or mixed evacuation and sheltering strategies. The calculations are based on externally generated, high resolution fallout deposition and plume data. Scenario setup and calculation outputs make extensive use of graphics and interactive features. This software is designed primarily to produce quantitative evaluations of nuclear detonation response options. However, the outputs have also proven useful in the communication of technical insights concerning shelter-evacuate tradeoffs to urban planning or response personnel.

  18. Timing system for firing widely spaced test nuclear detonations

    NASA Technical Reports Server (NTRS)

    Partridge, Ralph E.

    1992-01-01

    The national weapons design laboratories (Los Alamos National Laboratory and Lawrence Livermore National Laboratory) test fire nuclear devices at the Nevada Test Site (NTS), which is spread over an area of over 1200 square miles. On each test there are hundreds of high time resolution recordings made of nuclear output waveforms and other phenomena. In order to synchronize these recordings with each other, with the nuclear device, and with offsite recordings, there is a requirement that the permanent command center and the outlying temporary firing sites be time tied to each other and to UTC to permit firing the shot at a predetermined time with an accuracy of about a microsecond. Various aspects of the test setup and timing system are discussed.

  19. Medical planning and response for a nuclear detonation: a practical guide.

    PubMed

    Coleman, C Norman; Adams, Steven; Adrianopoli, Carl; Ansari, Armin; Bader, Judith L; Buddemeier, Brooke; Caro, J Jaime; Casagrande, Rocco; Case, Cullen; Caspary, Kevin; Chang, Arthur S; Chang, H Florence; Chao, Nelson; Cliffer, Kenneth D; Confer, Dennis; Deitchman, Scott; Derenzo, Evan G; Dobbs, Allen; Dodgen, Daniel; Donnelly, Elizabeth H; Gorman, Susan; Grace, Marcy Beth; Hatchett, Richard; Hick, John L; Hrdina, Chad; Jones, Robert; Kane, Elleen; Knebel, Ann; Koerner, John F; Laffan, Alison M; Larson, Leon; Livinski, Alicia; Mackinney, John; Maidment, Bert W; Manning, Ronald; Marinissen, Maria J; Martin, Colleen; Michael, Gretchen; Murrain-Hill, Paula; Nemhauser, Jeffrey B; Norwood, Ann E; Nystrom, Scott; Raheem, Murad; Redlener, Irwin; Sheehan, Kevin; Simon, Steven L; Taylor, Tammy P; Toner, Eric; Wallace, Katherine S; Wieder, Jessica; Weinstock, David M; Wiley, Albert L; Yeskey, Kevin; Miller, Charles W; Whitcomb, Robert C

    2012-12-01

    This article summarizes major points from a newly released guide published online by the Office of the Assistant Secretary for Preparedness and Response (ASPR). The article reviews basic principles about radiation and its measurement, short-term and long-term effects of radiation, and medical countermeasures as well as essential information about how to prepare for and respond to a nuclear detonation. A link is provided to the manual itself, which in turn is heavily referenced for readers who wish to have more detail. PMID:23244500

  20. Process for estimating likelihood and confidence in post detonation nuclear forensics.

    SciTech Connect

    Darby, John L.; Craft, Charles M.

    2014-07-01

    Technical nuclear forensics (TNF) must provide answers to questions of concern to the broader community, including an estimate of uncertainty. There is significant uncertainty associated with post-detonation TNF. The uncertainty consists of a great deal of epistemic (state of knowledge) as well as aleatory (random) uncertainty, and many of the variables of interest are linguistic (words) and not numeric. We provide a process by which TNF experts can structure their process for answering questions and provide an estimate of uncertainty. The process uses belief and plausibility, fuzzy sets, and approximate reasoning.

  1. Stochastic source comparisons between nuclear and chemical explosions detonated at Rainier Mesa, Nevada Test Site

    SciTech Connect

    Stump, B.W.; Pearson, D.C.; Reinke, R.E.

    1994-07-01

    The focus of this study is the understanding of the time function effects for chemical and nuclear explosion sources detonated in a spherical geometry. Information developed here in combination with similar studies for earthquakes and mining explosions will be used to improve current discriminants, address the transportability of the discriminants to new regions and suggest new discriminants utilizing current data sources. The quantification of the seismic source time function for nuclear and chemical explosions provides the basis for identifying source differences that may develop as a function of yield as well as explosive type (chemical or nuclear). The yield effects are useful in yield determination as well as assessing detection and identification capabilities if seismic monitoring of such sources is important. Source effects attributable to yield can be used to establish new or verify existing scaling relations.

  2. Social, psychological, and behavioral responses to a nuclear detonation in a US city: implications for health care planning and delivery.

    PubMed

    Dodgen, Daniel; Norwood, Ann E; Becker, Steven M; Perez, Jon T; Hansen, Cynthia K

    2011-03-01

    A nuclear detonation in a US city would have profound psychological, social, and behavioral effects. This article reviews the scientific literature on human responses to radiation incidents and disasters in general, and examines potential behavioral health care provider (BHCP) contributions in the hours and days after a nuclear detonation. In the area directly affected by the blast, the immediate overarching goal of BHCP interventions is the support of lifesaving activities and the prevention of additional casualties from fallout. These interventions include 6 broad categories: promoting appropriate protective actions, discouraging dangerous behaviors, managing patient/survivor flow to facilitate the best use of scarce resources, supporting first responders, assisting with triage, and delivering palliative care when appropriate. At more distant sites, BHCP should work with medical providers to support hospitalized survivors of the detonation. Recommendations are also made on BHCP interventions later in the response phase and during recovery. PMID:21402812

  3. Planning and Response to the Detonation of an Improvised Nuclear Device: Past, Present, and Future Research

    SciTech Connect

    Bentz, A

    2008-07-31

    While the reality of an improvised nuclear device (IND) being detonated in an American city is unlikely, its destructive power is such that the scenario must be planned for. Upon reviewing the academic literature on the effects of and response to IND events, this report looks to actual responders from around the country. The results from the meetings of public officials in the cities show where gaps exist between theoretical knowledge and actual practice. In addition to the literature, the meetings reveal areas where future research needs to be conducted. This paper recommends that local response planners: meet to discuss the challenges of IND events; offer education to officials, the public, and responders on IND events; incorporate 'shelter-first' into response plans; provide information to the public and responders using the 3 Cs; and engage the private sector (including media) in response plans. In addition to these recommendations for the response planners, the paper provides research questions that once answered will improve response plans around the country. By following the recommendations, both groups, response planners and researchers, can help the country better prepare for and mitigate the effects of an IND detonation.

  4. The effects of resolution, dimensionality, and nuclear network size on detonations in low-density Type Ia supernovae environments

    NASA Astrophysics Data System (ADS)

    Papatheodore, Thomas; Messer, O. E. Bronson; Hix, William R.

    2016-01-01

    Type Ia supernovae are most likely thermonuclear explosions of carbon/oxygen white dwarves in binary stellar systems, but the explosion scenario(s) that give rise to these events have still not been conclusively determined. However, nearly all of the currently favored explosion scenarios involve detonations, so we focus on this supersonic mode of burning. Using the FLASH code, we investigate the effects of resolution, dimensionality, and nuclear network size on detonations in low-density Type Ia supernova environments. We perform our simulations at small, resolved scales and then apply our findings to a large-scale application.

  5. Analysis of sheltering and evacuation strategies for an urban nuclear detonation scenario.

    SciTech Connect

    Yoshimura, Ann S.; Brandt, Larry D.

    2009-05-01

    Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. This study examines shelter-evacuate policies and effectiveness focusing on a 10 kt scenario in Los Angeles. The goal is to provide technical insights that can support development of urban response plans. Results indicate that extended shelter-in-place can offer the most robust protection when high quality shelter exists. Where less effective shelter is available and the fallout radiation intensity level is high, informed evacuation at the appropriate time can substantially reduce the overall dose to personnel. However, uncertainties in the characteristics of the fallout region and in the exit route can make evacuation a risky strategy. Analyses indicate that only a relatively small fraction of the total urban population may experience significant dose reduction benefits from even a well-informed evacuation plan.

  6. Isotopic fingerprinting of the world's first nuclear device using post-detonation materials.

    PubMed

    Bellucci, Jeremy J; Simonetti, Antonio; Wallace, Christine; Koeman, Elizabeth C; Burns, Peter C

    2013-04-16

    In the event of a rogue nuclear attack or interception of illicit nuclear materials, timely forensic investigations are critical for accurate source attribution. Uranium (U) and plutonium (Pu) isotopic ratios of intercepted materials or postdetonation samples are, perhaps, the most valuable evidence in modern nuclear forensics. These ratios simultaneously provide information regarding the material's ''age'' (i.e., time elapsed since last purification), actinide concentrations, and relevant isotopic ratios/enrichment values. Consequently, these isotope signatures are invaluable in determining the origin, processing history, and intended purpose of any nuclear material. Here we show, for the first time, that it is feasible to determine the U and Pu isotopic compositions of historic nuclear devices from their postdetonation materials utilizing in situ U isotopic measurements. The U isotopic compositions of trinitite glass, produced subsequent to the world's first atomic explosion, indicate two sources: the device's tamper, composed of natural U that underwent fission during detonation, and natural U from the geological background. Enrichments in (234,235,236)U reflect the in situ decay of (238,239,240)Pu, the fuel used in the device. Time-integrated U isotopic modeling yields "supergrade" compositions, where (240)Pu/(239)Pu ≈ 0.01-0.03 and (238)Pu/(239)Pu ≈ 0.00011-0.00017, which are consistent with the Pu originating from the Hanford reactor. Spatially resolved U isotopic data of postdetonation debris reveal important details of the device in a relatively short time frame (hours). This capacity serves as an important deterrent to future nuclear threats and/or terrorist activities and is critical for source attribution and international security. PMID:23517046

  7. Atmospheric transport of neutrons and gamma rays from near-horizon nuclear detonations

    SciTech Connect

    Byrd, R.C.; Heerema, B.D.

    1996-03-01

    This report continues a study of the transport of neutrons and rays from nuclear detonations at high altitudes to a set of detectors, with an emphasis on the limiting case of sources even beyond the horizon. To improve the calculational efficiency, the standard arrangement of a single source with multiple detectors is transformed to an equivalent one with a single detector and sources at multiple locations. Particular attention is paid to the critical problem of transport at near-horizon angles in an atmosphere whose density decreases exponentially with altitude. As a check, calculations for this region are made using both analytical and Monte Carlo approaches. For sources approaching the horizon, the fluence of gamma rays and neutrons reaching the detector drops gradually as the increasing column density attenuates the direct, unscattered fluence. Near the grazing angle, the direct fluence plummets, but the scattered component continues to decrease slowly and remains observable. Over this range, the timedependent flux of direct-plus-scattered gamma rays changes dramatically in both shape and magnitude, but it probably remains distinct from typical natural backgrounds. The neutron time-of-flight spectrum is dominated by scattering and reflects only the most important aspects of the original source spectrum; its most obvious features are a prominent low-energy tail and the resonance structure produced by nuclear interactions in the atmosphere. In some cases, the fluence of secondary gamma rays produced by these interactions may be larger than that from the source itself.

  8. Radioxenon Production and Transport from an Underground Nuclear Detonation to Ground Surface

    NASA Astrophysics Data System (ADS)

    Sun, Yunwei; Carrigan, Charles R.; Hao, Yue

    2015-02-01

    Radioxenon isotopes are considered as possible indicators for detecting and discriminating underground nuclear explosions. To monitor and sample the release of radioxenon isotopes, both independent and chain-reaction yields need to be considered together with multiphase transport in geological systems from the detonation point to the ground surface. For the sake of simplicity, modeling of radioxenon isotopic radioactivities has typically been focused either on chain reactions in a batch reactor without considering multiphase transport or on radionuclide transport with simplified reactions. Although numerical methods are available for integrating coupled differential equations of complex decay networks, the stiffness of ordinary differential equations due to greatly differing decay rates may require substantial additional effort to obtain solutions for the fully coupled system. For this reason, closed-form solutions for sequential reactions and numerical solutions for multiparent converging and multidaughter branching reactions were previously developed and used to simulate xenon isotopic radioactivities in the batch reactor mode. In this paper, we develop a fully coupled numerical model, which involves tracking 24 components (i.e., 22 radionuclide components plus air and water) in two phases to enhance model predictability of simultaneously simulating xenon isotopic transport and fully coupled chain reactions. To validate the numerical model and verify the corresponding computer code, we derived closed-form solutions for first-order xenon reactions in a batch reactor mode and for single-gas phase transport coupled with the xenon reactions in a one-dimensional column. Finally, cylindrical 3-D simulations of two-phase flow within a dual permeability fracture-matrix medium, simulating the geohydrologic regime of an underground nuclear explosion, indicate the existence of both a strong temporal and spatial dependence of xenon isotopic ratios sampled at the surface. In

  9. A possible approach to large-scale laboratory testing for acute radiation sickness after a nuclear detonation.

    PubMed

    Adalja, Amesh A; Watson, Matthew; Wollner, Samuel; Toner, Eric

    2011-12-01

    After the detonation of an improvised nuclear device, several key actions will be necessary to save the greatest number of lives possible. Among these tasks, the identification of patients with impending acute radiation sickness is a critical problem that so far has lacked a clear solution in national planning. We present one possible solution: the formation of a public-private partnership to augment the capacity to identify those at risk for acute radiation sickness. PMID:21988186

  10. Improved estimates of separation distances to prevent unacceptable damage to nuclear power plant structures from hydrogen detonation for gaseous hydrogen storage. Technical report

    SciTech Connect

    Not Available

    1994-05-01

    This report provides new estimates of separation distances for nuclear power plant gaseous hydrogen storage facilities. Unacceptable damage to plant structures from hydrogen detonations will be prevented by having hydrogen storage facilities meet separation distance criteria recommended in this report. The revised standoff distances are based on improved calculations on hydrogen gas cloud detonations and structural analysis of reinforced concrete structures. Also, the results presented in this study do not depend upon equivalencing a hydrogen detonation to an equivalent TNT detonation. The static and stagnation pressures, wave velocity, and the shock wave impulse delivered to wall surfaces were computed for several different size hydrogen explosions. Separation distance equations were developed and were used to compute the minimum separation distance for six different wall cases and for seven detonating volumes (from 1.59 to 79.67 lbm of hydrogen). These improved calculation results were compared to previous calculations. The ratio between the separation distance predicted in this report versus that predicted for hydrogen detonation in previous calculations varies from 0 to approximately 4. Thus, the separation distances results from the previous calculations can be either overconservative or unconservative depending upon the set of hydrogen detonation parameters that are used. Consequently, it is concluded that the hydrogen-to-TNT detonation equivalency utilized in previous calculations should no longer be used.

  11. Post-Detonation Nuclear Forensics: What will we do ``... when the explosions come ...''?

    NASA Astrophysics Data System (ADS)

    Fahey, A. J.

    2010-12-01

    “What will happen when the explosions come - when a part of New York or Cairo or Adelaide has been hollowed out by a device in the kiloton range? Since even a so called fizzle yield could kill a number of thousands of people, how many nuclear detonations can the world tolerate?” John McPhee, “The Curve of Binding Energy” On the morning of July 16, 1945 the first atomic bomb was exploded in New Mexico. The device was a Pu implosion device like the one that destroyed Nagasaki on August 9 of that year. If we were called upon to conduct a robust attribution process for an exploded device placed by a non-state actor, forensic analysis must yield information about not only the nuclear material in the device but about other materials that went into its construction. Those who perform the roles of forensic-analyst must have knowledge, not only of the possible construction of a nuclear weapon, but have at their disposal the knowledge and investigative skills that are common among geochemists. We have performed an investigation of glassed ground debris from the Trinity test (Trinitite) showing correlations among multiple analytical techniques. There is strong evidence, obtainable only through microanalysis, that secondary materials in the device can be identified and associated with the nuclear material. After a thin section of a piece of Trinitie was made, γ and α-spectrometry, autoradiography, light and, electron microscopy, x-ray analysis and secondary ion mass spectrometry were performed. Astonishing correlations exist in the data from these individual techniques. A plot of the correlation between several of the analyses is shown in Figure 1. The most significant feature is that the Pu is localized near the smooth top surface in a Ca-rich layer. This layer also contain U of natural isotopic composition. This is a definitive demonstration that the tamper material is associated with the nuclear material, in this case Pu, and can be identified as coming from a

  12. Health care system planning for and response to a nuclear detonation.

    PubMed

    Hick, John L; Weinstock, David M; Coleman, C Norman; Hanfling, Dan; Cantrill, Stephen; Redlener, Irwin; Bader, Judith L; Murrain-Hill, Paula; Knebel, Ann R

    2011-03-01

    The hallmark of a successful response to a nuclear detonation will be the resilience of the community, region, and nation. An incident of this magnitude will rapidly become a national incident; however, the initial critical steps to reduce lives lost, save the lives that can be saved with the resources available, and understand and apply resources available to a complex and dynamic situation will be the responsibility of the local and regional responders and planners. Expectations of the public health and health care systems will be met to the extent possible by coordination, cooperation, and an effort to produce as consistent a response as possible for the victims. Responders will face extraordinarily stressful situations, and their own physical and psychological health is of great importance to optimizing the response. This article illustrates through vignettes and supporting text how the incident may unfold for the various components of the health and medical systems and provides additional context for the discipline-related actions outlined in the state and local planners' playbook. PMID:21402815

  13. Failure modes of a concrete nuclear-containment building subjected to hydrogen detonation

    SciTech Connect

    Fugelso, L.E.; Butler, T.A.

    1983-01-01

    Calculated response for the Indian Point reactor containment building to static internal pressure and one case of a dynamic pressure representing hydrogen combustion and detonation are presented. Comparison of the potential failure modes is made. 9 figures.

  14. Public Health and Medical Preparedness for a Nuclear Detonation: The Nuclear Incident Medical Enterprise

    PubMed Central

    Coleman, C. Norman; Sullivan, Julie M.; Bader, Judith L.; Murrain-Hill, Paula; Koerner, John F.; Garrett, Andrew L.; Weinstock, David M.; Case, Cullen; Hrdina, Chad; Adams, Steven A.; Whitcomb, Robert C.; Graeden, Ellie; Shankman, Robert; Lant, Timothy; Maidment, Bert W.; Hatchett, Richard C.

    2014-01-01

    Resilience and the ability to mitigate the consequences of a nuclear incident are enhanced by (1) effective planning, preparation and training; (2) ongoing interaction, formal exercises, and evaluation among the sectors involved; (3) effective and timely response and communication; and (4) continuous improvements based on new science, technology, experience and ideas. Public health and medical planning require a complex, multi-faceted systematic approach involving federal, state, local, tribal and territorial governments, private sector organizations, academia, industry, international partners, and individual experts and volunteers. The approach developed by the U.S. Department of Health and Human Services Nuclear Incident Medical Enterprise (NIME) is the result of efforts from government and nongovernment experts. It is a “bottom-up” systematic approach built on the available and emerging science that considers physical infrastructure damage, the spectrum of injuries, a scarce resources setting, the need for decision making in the face of a rapidly evolving situation with limited information early on, timely communication and the need for tools and just-in-time information for responders who will likely be unfamiliar with radiation medicine and uncertain and overwhelmed in the face of the large number of casualties and the presence of radioactivity. The components of NIME can be used to support planning for, response to, and recovery from the effects of a nuclear incident. Recognizing that it is a continuous work-in-progress, the current status of the public health and medical preparedness and response for a nuclear incident is provided. PMID:25551496

  15. Public health and medical preparedness for a nuclear detonation: the nuclear incident medical enterprise.

    PubMed

    Coleman, C Norman; Sullivan, Julie M; Bader, Judith L; Murrain-Hill, Paula; Koerner, John F; Garrett, Andrew L; Weinstock, David M; Case, Cullen; Hrdina, Chad; Adams, Steven A; Whitcomb, Robert C; Graeden, Ellie; Shankman, Robert; Lant, Timothy; Maidment, Bert W; Hatchett, Richard C

    2015-02-01

    Resilience and the ability to mitigate the consequences of a nuclear incident are enhanced by (1) effective planning, preparation and training; (2) ongoing interaction, formal exercises, and evaluation among the sectors involved; (3) effective and timely response and communication; and (4) continuous improvements based on new science, technology, experience, and ideas. Public health and medical planning require a complex, multi-faceted systematic approach involving federal, state, local, tribal, and territorial governments; private sector organizations; academia; industry; international partners; and individual experts and volunteers. The approach developed by the U.S. Department of Health and Human Services Nuclear Incident Medical Enterprise (NIME) is the result of efforts from government and nongovernment experts. It is a "bottom-up" systematic approach built on the available and emerging science that considers physical infrastructure damage, the spectrum of injuries, a scarce resources setting, the need for decision making in the face of a rapidly evolving situation with limited information early on, timely communication, and the need for tools and just-in-time information for responders who will likely be unfamiliar with radiation medicine and uncertain and overwhelmed in the face of the large number of casualties and the presence of radioactivity. The components of NIME can be used to support planning for, response to, and recovery from the effects of a nuclear incident. Recognizing that it is a continuous work-in-progress, the current status of the public health and medical preparedness and response for a nuclear incident is provided. PMID:25551496

  16. On the possibility of the realization of combustion and detonation waves in a system of nuclear isomers

    NASA Astrophysics Data System (ADS)

    Arutyunyan, R. V.; Akhrameev, E. V.; Bolshov, L. A.; Kondratenko, P. S.; Tkalya, E. V.

    2014-02-01

    The possible regimes of the propagation of a self-sustained fluorescence wave of long-lived nuclear isomers, which is initiated by transitions to the nearest short-lived level owing to the absorption of X-ray photons and inelastic collisions of electrons in a plasma, have been analyzed. It has been found that, when the energy exchange between the nuclear subsystem and plasma is due to absorption and emission of photons, the fluorescence wave can propagate in the fast (with a near-light velocity) deflagration regime induced by the radiative heat transfer mechanism. When the energy exchange between the subsystems is nonradiative, the (slower) detonation regime becomes significant. The implementation of each of the two regimes requires certain conditions on the characteristics of the system.

  17. Operation Hardtack. Project 1. 4. Physical characteristics of craters from near-surface nuclear detonations. Report for April-October 1958

    SciTech Connect

    Patteson, A.W.

    1984-10-31

    The objective of this project was to measure and correlate with existing data the physical characteristics of craters (radius, depth, lip height and width, throwout, and permanent vertical ground-surface displacement surrounding the crater) resulting from near-surface nuclear detonations.

  18. Derivation of models for nuclear weapon terrorist arming and detonation risk analysis

    SciTech Connect

    Parziale, A A

    1998-03-01

    This report investigates "use control" for the on-site arming and detonation, by terrorists, of stored weapon systems. We investigate both components of weapon "use control", which we define as: (1) weapon "use denial" * that we model as a probability, Pj (denial), that represents the chances that terrorists attempting to arm a type j weapon will commit a non-recoverable error, and (2) weapon "use delay" that we model as a random variable, Tj , that represents the arming delay imposed by the use control features of a type j weapon, before detonation can occur. Using information pertaining to the physical security system at a storage site, the postulated terrorist attack force size, and simulated combat engagement outcomes, we formulate the frequency, fj , and probability, P(dj ), of on-site detonation, for generic weapon types j. We derive a model that disjoins the performance of site physical security, from that for weapon use control, if the use control random variable Tj has a Uniform or histogram distribution. This is an especially significant result where most complex distributions can be adequately approximated with a histogram. Hence, we can conduct combat simulations to obtain the physical security performance of a specific storage site independent of the use control features associated with specific weapon types that are stored, or might be stored, at the site. In turn, we can obtain the use control performance for various weapon types, independent of where they are stored and the physical security systems surrounding them. Our models can then mathematically combine physical security performance and weapon use control performance for any combination of storage facility and weapon type.

  19. Detonating apparatus

    DOEpatents

    Johnston, Lawrence H.

    1976-01-01

    1. Apparatus for detonation of high explosive in uniform timing comprising in combination, an outer case, spark gap electrodes insulatedly supported in spaced relationship within said case to form a spark gap, high explosive of the class consisting of pentaerythritol tetranitrate and trimethylene trinitramine substantially free from material sensitive to detonation by impact compressed in surrounding relation to said electrodes including said spark gap under a pressure from about 100 psi to about 500 psi, said spark gap with said compressed explosive therein requiring at least 1000 volts for sparking, and means for impressing at least 1000 volts on said spark gap.

  20. Analysis of fission and activation radionuclides produced by a uranium-fueled nuclear detonation and identification of the top dose-producing radionuclides.

    PubMed

    Kraus, Terry; Foster, Kevin

    2014-08-01

    The radiological assessment of the nuclear fallout (i.e., fission and neutron-activation radionuclides) from a nuclear detonation is complicated by the large number of fallout radionuclides. This paper provides the initial isotopic source term inventory of the fallout from a uranium-fueled nuclear detonation and identifies the significant and insignificant radiological dose producing radionuclides over 11 dose integration time periods (time phases) of interest. A primary goal of this work is to produce a set of consistent, time phase-dependent lists of the top dose-producing radionuclides that can be used to prepare radiological assessment calculations and data products (e.g., maps of areas that exceed protective action guidelines) in support of public and worker protection decisions. The ranked lists of top dose-producing radionuclides enable assessors to perform atmospheric dispersion modeling and radiological dose assessment modeling more quickly by using relatively short lists of radionuclides without significantly compromising the accuracy of the modeling and the dose projections. This paper also provides a superset-list of the top dose-producing fallout radionuclides from a uranium-fueled nuclear detonation that can be used to perform radiological assessments over any desired time phase. Furthermore, this paper provides information that may be useful to monitoring and sampling and laboratory analysis personnel to help understand which radionuclides are of primary concern. Finally, this paper may be useful to public protection decision makers because it shows the importance of quickly initiating public protection actions to minimize the radiological dose from fallout. PMID:24978286

  1. Standard KDF0C4 Fallout Calculations for Buried Nuclear Detonations

    SciTech Connect

    Serduke, F J D

    2001-09-14

    The collateral damage caused by fallout from shallow-buried nuclear devices is of considerable interest. In this paper, we present results for ''standard'' calculations using the KDFOC4 fallout computer code. Results are presented for a parametric range of yields from 0.1 kt to 1 Mt in equally-spaced logarithmic increments and for emplacement depths of 5 meters in hard, dry rock and 20 meters in moist soil. We will see that for low yields, this emplacement depth has a marked influence on the shape of the fallout patterns but for the highest yields, the fallout patterns are insensitive to the emplacement medium and depth. We look at two categories of doses: (1) Those for which health effects begin to be serious and range upward to lethal, and (2) Doses that are politically very sensitive but for which any deleterious health effects are difficult to prove.

  2. Role of dicentric analysis in an overarching biodosimetry strategy for use following a nuclear detonation in an urban environment.

    PubMed

    Blumenthal, Daniel J; Sugarman, Stephen L; Christensen, Doran M; Wiley, Albert L; Livingston, Gordon K; Glassman, Erik S; Koerner, John F; Sullivan, Julie M; Hinds, Sidney

    2014-04-01

    In the moments immediately following a nuclear detonation, casualties with a variety of injuries including trauma, burns, radiation exposure, and combined injuries would require immediate assistance. Accurate and timely radiation dose assessments, based on patient history and laboratory testing, are absolutely critical to support adequately the triage and treatment of those affected. This capability is also essential for ensuring the proper allocation of scarce resources and will support longitudinal evaluation of radiation-exposed individuals and populations. To maximize saving lives, casualties must be systematically triaged to determine what medical interventions are needed, the nature of those interventions, and who requires intervention immediately. In the National Strategy for Improving the Response and Recovery for an Improvised Nuclear Device (IND) Attack, the U.S. Department of Homeland Security recognized laboratory capacity for radiation biodosimetry as having a significant gap for performing mass radiation dose assessment. The anticipated demand for radiation biodosimetry exceeds its supply, and this gap is partly linked to the limited number and analytical complexity of laboratory methods for determining radiation doses within patients. The dicentric assay is a key component of a cytogenetic biodosimetry response asset, as it has the necessary sensitivity and specificity for assessing medically significant radiation doses. To address these shortfalls, the authors have developed a multimodal strategy to expand dicentric assay capacity. This strategy includes the development of an internet-based cytogenetics network that would address immediately the labor intensive burden of the dicentric chromosome assay by increasing the number of skilled personnel to conduct the analysis. An additional option that will require more time includes improving surge capabilities by combining resources available within the country's 150 clinical cytogenetics laboratories

  3. Multiple-code benchmark simulation study of coupled THMC processesin the excavation disturbed zone associated with geological nuclear wasterepositories

    SciTech Connect

    Rutqvist, J.; Feng, X-T.; Hudson, J.; Jing, L.; Kobayashi, A.; Koyama, T.; Pan, P-Z.; Lee, H-S.; Rinne, M.; Sonnenthal, E.; Yamamoto, Y.

    2006-05-10

    An international, multiple-code benchmark test (BMT) studyis being conducted within the international DECOVALEX project to analysecoupled thermal, hydrological, mechanical and chemical (THMC) processesin the excavation disturbed zone (EDZ) around emplacement drifts of anuclear waste repository. This BMT focuses on mechanical responses andlong-term chemo-mechanical effects that may lead to changes in mechanicaland hydrological properties in the EDZ. This includes time-de-pendentprocesses such as creep, and subcritical crack, or healing of fracturesthat might cause "weakening" or "hardening" of the rock over the longterm. Five research teams are studying this BMT using a wide range ofmodel approaches, including boundary element, finite element, and finitedifference, particle mechanics, and elasto-plastic cellular automatamethods. This paper describes the definition of the problem andpreliminary simulation results for the initial model inception part, inwhich time dependent effects are not yet included.

  4. Multiple-Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories

    SciTech Connect

    J. Rutqvist; X. Feng; J. Hudson; L. Jing; A. Kobayashi; T. Koyama; P.Pan; H. Lee; M. Rinne; E. Sonnenthal; Y. Yamamoto

    2006-05-08

    An international, multiple-code benchmark test (BMT) study is being conducted within the international DECOVALEX project to analyze coupled thermal, hydrological, mechanical and chemical (THMC) processes in the excavation disturbed zone (EDZ) around emplacement drifts of a nuclear waste repository. This BMT focuses on mechanical responses and long-term chemo-mechanical effects that may lead to changes in mechanical and hydrological properties in the EDZ. This includes time-dependent processes such as creep, and subcritical crack, or healing of fractures that might cause ''weakening'' or ''hardening'' of the rock over the long term. Five research teams are studying this BMT using a wide range of model approaches, including boundary element, finite element, and finite difference, particle mechanics, and elasto-plastic cellular automata methods. This paper describes the definition of the problem and preliminary simulation results for the initial model inception part, in which time dependent effects are not yet included.

  5. Goals, Objectives, and Requirements (GOR) of the Ground-based Nuclear Detonation Detection (GNDD) Team for the Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D)

    SciTech Connect

    Casey, Leslie A.

    2014-01-13

    The goal, objectives, and requirements (GOR) presented in this document define a framework for describing research directed specifically by the Ground-based Nuclear Detonation Detection (GNDD) Team of the National Nuclear Security Administration (NNSA). The intent of this document is to provide a communication tool for the GNDD Team with NNSA management and with its stakeholder community. It describes the GNDD expectation that much of the improvement in the proficiency of nuclear explosion monitoring will come from better understanding of the science behind the generation, propagation, recording, and interpretation of seismic, infrasound, hydroacoustic, and radionuclide signals and development of "game-changer" advances in science and technology.

  6. Crane and Excavator Operator.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on crane and excavator operation is designed to enable the crane and excavator operator to perform his/her duties more proficiently. Introductory materials include specific information for MCI students, a course introduction, and a study guide…

  7. Continuous detonation reaction engine

    NASA Technical Reports Server (NTRS)

    Lange, O. H.; Stein, R. J.; Tubbs, H. E.

    1968-01-01

    Reaction engine operates on the principles of a controlled condensed detonation rather than on the principles of gas expansion. The detonation results in reaction products that are expelled at a much higher velocity.

  8. High temperature detonator

    DOEpatents

    Johnson, James O.; Dinegar, Robert H.

    1988-01-01

    A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

  9. Hydromechanical Advanced Coal Excavator

    NASA Technical Reports Server (NTRS)

    Estus, Jay M.; Summers, David

    1990-01-01

    Water-jet cutting reduces coal dust and its hazards. Advanced mining system utilizes full-face, hydromechanical, continuous miner. Coal excavator uses high-pressure water-jet lances, one in each of cutting heads and one in movable lance, to make cuts across top, bottom and middle height, respectively, of coal face. Wedge-shaped cutting heads advance into lower and upper cuts in turn, thereby breaking coal toward middle cut. Thrust cylinders and walking pads advance excavator toward coal face.

  10. Detonation Wave Profile

    SciTech Connect

    Menikoff, Ralph

    2015-12-14

    The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.

  11. Reflected Detonation Waves: Comparing Theory to Pressure and Heat Flux Measurements

    NASA Astrophysics Data System (ADS)

    Damazo, J.; Shepherd, J. E.

    Gaseous detonations are of concern to engineers designing piping systems for chemical and nuclear processing facilities. Recently, engineers have also begun to explore the possibility of harnessing the impulse created by detonations for thrust.

  12. Transition to Detonation in Exploding Bridgewire Detonators

    SciTech Connect

    Roeski, F; Benterou, J; Lee, R; Roos, R

    2003-01-08

    We are investigating using breakout profile measurements and/or Fabry-Perot velocimeter measurements during early stages of initiation in Exploding Bridge Wire (EBW) detonators as a tool for understanding the physics of initiation of these devices and as a tool for monitoring aging effects. We believe any changes due to aging may be more readily observed in the very early stages of the initiation. We have developed a method that allows measurement of the detonation velocity, detonation profile and interface velocity as a function of distance from the bridgewire.

  13. Lunar Regolith Excavation Competition

    NASA Technical Reports Server (NTRS)

    Liles, Cassandra

    2009-01-01

    The Lunar Regolith Excavation Competition is a new competition that needs graphics, logos, rules, as well as an arena. Although this is the first year of the competition, the competition is modeled after an existing competition, the Centennial Lunar Excavator Challenge. This competition however is aimed at college students. This makes the challenge identifying key aspects of the original competition and modeling them to fit into an easier task, and creating exciting advertisement that helps encourage participation. By using a youth focus group, young insight, as well as guiding advice from experts in the field, hopefully an arena can be designed and built, rules can be molded and created to fit, and alluring graphics can be printed to bring about a successful first year of the Lunar Regolith Excavation Competition.

  14. Mobile continuous lunar excavation

    NASA Technical Reports Server (NTRS)

    Paterson, John L.

    1992-01-01

    A novel approach to the concept of lunar mining and the use of in situ oxygen, metallics, and ceramics is presented. The EVA time required to set up, relocate, and maintain equipment, as well as the cost per pound of shipping the mining and processing equipment to the moon are considered. The proposed soil fracturing/loading mechanisms are all based loosely on using the Apollo Lunar Roving Vehicle (LRV) Frame. All use motor driven tracks for mobility in the forward/reverse and left/right direction. All mechanisms employ the concept of rototillers which are attached to a gantry which, through the use of motor-driven lead screws, provide the rototillers with an up/down capability. A self-reactant excavator, a local mass enhanced excavator, and a soil reactant excavator are illustrated.

  15. Isothermal Gaseous Detonation Model

    NASA Astrophysics Data System (ADS)

    Prokhorov, E. S.

    2015-05-01

    We propose an isothermal gaseous detonation model taking into account the initial pressure of the explosive mixture that permits describing in a simplified form both the self-sustaining and the supercompressed and undercompressed detonation regimes. The exactness of this model has been estimated on the basis of a comparative analysis with the results of equilibrium calculations of the gas-dynamic parameters at the front of detonation waves.

  16. Hydrazine vapor detonations

    NASA Technical Reports Server (NTRS)

    Pedley, M. D.; Bishop, C. V.; Benz, F. J.; Bennett, C. A.; Mcclenagan, R. D.

    1988-01-01

    The detonation velocity and cell widths for hydrazine decomposition were measured over a wide range of temperatures and pressures. The detonation velocity in pure hydrazine was within 5 percent of the calculated C-J velocity. The detonation cell width measurements were interpreted using the Zeldovich-Doering-von Neumann model with a detailed reaction mechanism for hydrazine decomposition. Excellent agreement with experimental data for pure hydrazine was obtained using the empirical relation that detonation cell width was equal to 29 times the kinetically calculated reaction zone length.

  17. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2016-05-31

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link there between. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  18. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2015-11-10

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link therebetween. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  19. 1-D detonability

    NASA Astrophysics Data System (ADS)

    Guirguis, R. H.

    1996-05-01

    The likelihood of an energetic material to detonate is expressed in terms of the thermicity σ.dλ/dt within the reaction zone of an incipient one-dimensional detonation wave propagating in the material. Ranking conventional explosives according to σ alone was found to reasonably parallel the ranking according to critical diameter.

  20. Bidirectional slapper detonator

    DOEpatents

    McCormick, Robert N.; Boyd, Melissa D.

    1984-01-01

    The disclosure is directed to a bidirectional slapper detonator. One embodiment utilizes a single bridge circuit to detonate a pair of opposing initiating pellets. A line generator embodiment uses a plurality of bridges in electrical series to generate opposing cylindrical wavefronts.

  1. On gas detonation limits

    SciTech Connect

    Nikolaev, Yu.A.; Gapanov, O.A.

    1995-11-01

    A one-dimensional model for a multiheaded detonation has been constructed with account for friction, heat losses, and the decay of gas velocity pulsations. The existence of detonation limits in narrow channels has been numerically shown. The calculation results are in satisfactory agreement with experimental data.

  2. Implications of an Improvised Nuclear Device Detonation on Command and Control for Surrounding Regions at the Local, State and Federal Levels

    SciTech Connect

    Pasquale, David A.; Hansen, Richard G.

    2013-01-23

    This paper discusses command and control issues relating to the operation of Incident Command Posts (ICPs) and Emergency Operations Centers (EOCs) in the surrounding area jurisdictions following the detonation of an Improvised Nuclear Device (IND). Although many aspects of command and control will be similar to what is considered to be normal operations using the Incident Command System (ICS) and the National Incident Management System (NIMS), the IND response will require many new procedures and associations in order to design and implement a successful response. The scope of this white paper is to address the following questions: • Would the current command and control framework change in the face of an IND incident? • What would the management of operations look like as the event unfolded? • How do neighboring and/or affected jurisdictions coordinate with the state? • If the target area’s command and control infrastructure is destroyed or disabled, how could neighboring jurisdictions assist with command and control of the targeted jurisdiction? • How would public health and medical services fit into the command and control structure? • How can pre-planning and common policies improve coordination and response effectiveness? • Where can public health officials get federal guidance on radiation, contamination and other health and safety issues for IND response planning and operations?

  3. Propagation Mechanism of Cylindrical Cellular Detonation

    NASA Astrophysics Data System (ADS)

    Han, Wen-Hu; Wang, Cheng; Ning, Jian-Guo

    2012-10-01

    We investigate the evolution of cylindrical cellular detonation with different instabilities. The numerical results show that with decreasing initial temperature, detonation becomes more unstable and the cells of the cylindrical detonation tend to be irregular. For stable detonation, a divergence of cylindrical detonation cells is formed eventually due to detonation instability resulting from a curved detonation front. For mildly unstable detonation, local overdriven detonation occurs. The detonation cell diverges and its size decreases. For highly unstable detonation, locally driven detonation is more obvious and the front is highly wrinkled. As a result, the diverging cylindrical detonation cell becomes highly irregular.

  4. Development of detonation reaction engine

    NASA Technical Reports Server (NTRS)

    Lange, O. H.; Stein, R. J.; Tubbs, H. E.

    1968-01-01

    Reaction engine operates on the principle of a controlled condensed detonation. In this engine the gas products that are expelled from the engine to produce thrust are generated by the condensed detonation reaction. The engine is constructed of two basic sections consisting of a detonation wave generator section and a condensed detonation reaction section.

  5. Detonation Front Curvatures and Detonation Rates

    NASA Astrophysics Data System (ADS)

    Lauderbach, Lisa M.; Lorenz, K. Thomas; Lee, Edward L.; Souers, P. Clark

    2015-06-01

    We have normalized the LLNL library of detonation front curvatures by dividing lags by the edge lag and radii by the edge radius. We then fit the normalized data to the equation L = AR2 + BR8, where L is the normalized lag and R is the normalized radius. We attribute the quadratic term to thermal processes and the 8th-power term to shock processes. We compare the % of the quadratic term J at the edge with detonation rates obtained from the size effect. One class of results is made up of fine-grained, uniform explosives with large lags, where a low detonation rate leads to a high J and vice versa. This provides a rough way of estimating unknown rates if the unknown explosive is of high quality. The other, equally-large class contains rough-grained materials, often with small lags and small radii. These have curves that do not fit the equation but superfically often look quadratic. Some HMX and PETN curvatures even show a ``sombrero'' effect. Code models show that density differences of 0.03 g/cc in ram-pressed parts can cause pseudo-quadratic curves and even sombreros. Modeling is used to illustrate J at the lowest and highest possible detonation rates. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. Excavator Design Validation

    NASA Technical Reports Server (NTRS)

    Pholsiri, Chalongrath; English, James; Seberino, Charles; Lim, Yi-Je

    2010-01-01

    The Excavator Design Validation tool verifies excavator designs by automatically generating control systems and modeling their performance in an accurate simulation of their expected environment. Part of this software design includes interfacing with human operations that can be included in simulation-based studies and validation. This is essential for assessing productivity, versatility, and reliability. This software combines automatic control system generation from CAD (computer-aided design) models, rapid validation of complex mechanism designs, and detailed models of the environment including soil, dust, temperature, remote supervision, and communication latency to create a system of high value. Unique algorithms have been created for controlling and simulating complex robotic mechanisms automatically from just a CAD description. These algorithms are implemented as a commercial cross-platform C++ software toolkit that is configurable using the Extensible Markup Language (XML). The algorithms work with virtually any mobile robotic mechanisms using module descriptions that adhere to the XML standard. In addition, high-fidelity, real-time physics-based simulation algorithms have also been developed that include models of internal forces and the forces produced when a mechanism interacts with the outside world. This capability is combined with an innovative organization for simulation algorithms, new regolith simulation methods, and a unique control and study architecture to make powerful tools with the potential to transform the way NASA verifies and compares excavator designs. Energid's Actin software has been leveraged for this design validation. The architecture includes parametric and Monte Carlo studies tailored for validation of excavator designs and their control by remote human operators. It also includes the ability to interface with third-party software and human-input devices. Two types of simulation models have been adapted: high-fidelity discrete

  7. Smooth blasting with the electronic delay detonator

    SciTech Connect

    Yamamoto, Masaaki; Ichijo, Toshiyuki; Tanaka, Yoshiharu

    1995-12-31

    The authors utilized electronic detonators (EDs) to investigate the effect of high detonator delay accuracy on overbreak, remaining rock damage, and surface smoothness, in comparison with that of long-period delay detonators (0.25 sec interval) PDs. The experiments were conducted in a deep mine, in a test site region composed of very hard granodiorite with a seismic wave velocity of about 6.0 km/sec and a uniaxial compressive strength, uniaxial tensile strength, and Young`s modulus of 300 MPa, 12 MPa, and 73 GPa, respectively. The blasting design was for a test tunnel excavation of 8 m{sup 2} in cross section, with an advance per round of 2.5 m. Five rounds were performed, each with a large-hole cut and perimeter holes in a 0.4-m spacing charged with 20-mm-diameter water gel explosive to obtain low charge concentration. EDs were used in the holes on the perimeter of the right half, and PDs were used in all other holes. Following each shot, the cross section was measured by laser to determine amount of overbreak and surface smoothness. In situ seismic prospecting was used to estimate the depth of damage in the remaining rock, and the damage was further investigated by boring into both side walls.

  8. Optically detonated explosive device

    NASA Technical Reports Server (NTRS)

    Yang, L. C.; Menichelli, V. J. (Inventor)

    1974-01-01

    A technique and apparatus for optically detonating insensitive high explosives, is disclosed. An explosive device is formed by containing high explosive material in a house having a transparent window. A thin metallic film is provided on the interior surface of the window and maintained in contact with the high explosive. A laser pulse provided by a Q-switched laser is focussed on the window to vaporize the metallic film and thereby create a shock wave which detonates the high explosive. Explosive devices may be concurrently or sequentially detonated by employing a fiber optic bundle to transmit the laser pulse to each of the several individual explosive devices.

  9. Direct observation detonator operation

    NASA Astrophysics Data System (ADS)

    Hall, Charles R.

    2001-11-01

    The analysis of detonator-timing performance has involved the use of rotating-mirror cameras (RMC) used in the streak mode and high-speed film. Fiducial timing marks are applied to the film to provide temporal references. The use of a RMC for detonator analysis requires aligning the camera, performing an exposure test, capturing light from the detonation and then processing the film. This procedure can take up to an hour for two technicians. After the film is possessed another technician compares each light streak on the film with the fiducial timing marks also recorded on the film. Capturing light from a detonator and recording it directly to a digitizer can improve detonator-timing measurement in several ways. The digitized signals can then be directly analyzed with software. The direct recording method reduces the need for expensive rotating mirror cameras, film processing and subjective optical measurement comparison. Furthermore, an extensive support facility requiring several specialized technicians is reduced to a single technician in a modest laboratory. This technician is then capable of performing several tests an hour. Tests were preformed to measure light intensity at detonation. An optical method of capturing the light was designed using a remote microscope coupled to optical fiber to bring the light to an optical/electrical converter and a digitizer then records the signal. This system is presently used in parallel with a RMC. The results are compared for accuracy.

  10. Theory of gaseous detonations.

    PubMed

    Clavin, Paul

    2004-09-01

    The objective of the present paper is to review some developments that have occurred in detonation theory over the last ten years. They concern nonlinear dynamics of detonation fronts, namely patterns of pulsating and/or cellular fronts, selection of the cell size, dynamical self-quenching, direct (blast) or spontaneous initiation, and transition from deflagration to detonation. These phenomena are all well documented by experiments since the sixties but remained unexplained until recently. In the first part of the paper, the patterns of cellular detonations are described by an asymptotic solution to nonlinear hyperbolic equations (reactive Euler equations) in the form of unsteady (sometime chaotic) and multidimensional traveling-waves. In the second part, turning points of quasi-steady solutions are shown to correspond to critical conditions of fully unsteady problems, either for (direct or spontaneous) initiation or for spontaneous failure (self-quenching). Physical insights are tentatively presented rather than technical aspects. The challenge is to identify the physical mechanisms with their relevant parameters, and more specifically to explain how the length-scales involved in detonation dynamics are larger by two order of magnitude (at least) than the length-scale involved in the steady planar traveling-wave solution (detonation thickness). PMID:15446993

  11. Miniature plasma accelerating detonator and method of detonating insensitive materials

    SciTech Connect

    Bickes, R.W. Jr.; Kopczewski, M.R.; Schwarz, A.C.

    1986-11-11

    This patent describes a detonator assembly for initiating insensitive explosives or energetic materials. In the improvement described here the detonator assembly comprises: railgun accelerating means of a size sufficient to be used as a detonator for insensitive explosives or energetic materials in an amount of about 100 mg of explosives or less and capable of accelerating a plasma to detonation initiating velocities; and power supply means for supplying the power necessary to the railgun accelerating means to generate and accelerate the plasma.

  12. Shoring pumping station excavation

    SciTech Connect

    Glover, J.B.; Reardon, D.J. )

    1991-11-01

    The city of San Mateo, Calif., operates three 12- to 50-year old wastewater pumping stations on a 24-m (80-ft) wide lot located in a residential area near San Francisco Bay. Because the aging stations have difficulty pumping peak 2.19-m{sup 3}/s (50-mgd) wet-weather flows and have structural and maintenance problems, a new 2.62-m{sup 3}/s (60-mgd) station was proposed - the Dale Avenue Pumping Station - to replace the existing ones. To prevent potential damage to adjacent homes, the new station was originally conceived as a circular caisson type; however, a geotechnical investigation recommended against this type of structure because the stiff soils could make sinking the structure difficult. This prompted an investigation of possible shoring methods for the proposed structure. Several shoring systems were investigated, including steel sheeting, soldier beams and lagging, tieback systems, open excavation, and others; however, each had disadvantages that prevented its use. Because these conventional techniques were unacceptable, attention was turned to using deep soil mixing (DSM) to create a diaphragm wall around the area to be excavated before constructing the pumping station. Although this method has been used extensively in Japan since 1983, the Dale Avenue Pumping Station would be the technology's first US application. The technology's anticipated advantages were its impermeability, its fast and efficient installation that did not require tiebacks under existing homes, its adaptability to subsurface conditions ranging from soft ground to stiff clay to gravels, and its lack of pile-driving requirements that would cause high vibration levels during installation.

  13. Reverse slapper detonator

    DOEpatents

    Weingart, Richard C.

    1990-01-01

    A reverse slapper detonator (70), and methodology related thereto, are provided. The detonator (70) is adapted to be driven by a pulse of electric power from an external source (80). A conductor (20) is disposed along the top (14), side (18), and bottom (16) surfaces of a sheetlike insulator (12). Part of the conductor (20) comprises a bridge (28), and an aperture (30) is positioned within the conductor (20), with the bridge (28) and the aperture (30) located on opposite sides of the insulator (12). A barrel (40) and related explosive charge (50) are positioned adjacent to and in alignment with the aperture (30), and the bridge (28) is buttressed with a backing layer (60). When the electric power pulse vaporizes the bridge (28), a portion of the insulator (12) is propelled through the aperture (30) and barrel (40), and against the explosive charge (50), thereby detonating it.

  14. Nonequilibrium detonation of composite explosives

    SciTech Connect

    Nichols III, A.L.

    1997-07-01

    The effect of nonequilibrium diffusional flow on detonation velocities in composite explosives is examined. Detonation conditions are derived for complete equilibrium, temperature and pressure equilibrium, and two forms of pressure equilibrium. Partial equilibria are associated with systems which have not had sufficient time for transport to smooth out the gradients between spatially separate regions. The nonequilibrium detonation conditions are implemented in the CHEQ equation of state code. We show that the detonation velocity decreases as the non-chemical degrees of freedom of the explosive are allowed to equilibrate. It is only when the chemical degrees of freedom are allowed to equilibrate that the detonation velocity increases.

  15. Conditions for Successful Helium Detonations in Astrophysical Environments

    NASA Astrophysics Data System (ADS)

    Holcomb, Cole; Guillochon, James; De Colle, Fabio; Ramirez-Ruiz, Enrico

    2013-07-01

    Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range between 1 and 1010 cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of ~100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M ⊙ can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that 40Ca, 44Ti, or 48Cr, rather than 56Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and 56Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.

  16. Clamp for detonating fuze

    NASA Technical Reports Server (NTRS)

    Holderman, E. J.

    1968-01-01

    Quick acting clamp provides physical support for a closely confined detonating fuse in an application requiring removal and replacement at frequent intervals during test. It can be designed with a base of any required strength and configuration to permit the insertion of an object.

  17. Environmentally Benign Stab Detonators

    SciTech Connect

    Gash, A

    2005-12-21

    Many energetic systems can be activated via mechanical means. Percussion primers in small caliber ammunition and stab detonators used in medium caliber ammunition are just two examples. Current medium caliber (20-60mm) munitions are detonated through the use of impact sensitive stab detonators. Stab detonators are very sensitive and must be small, as to meet weight and size limitations. A mix of energetic powders, sensitive to mechanical stimulus, is typically used to ignite such devices. Stab detonators are mechanically activated by forcing a firing pin through the closure disc of the device and into the stab initiating mix. Rapid heating caused by mechanically driven compression and friction of the mixture results in its ignition. The rapid decomposition of these materials generates a pressure/temperature pulse that is sufficient to initiate a transfer charge, which has enough output energy to detonate the main charge. This general type of ignition mix is used in a large variety of primers, igniters, and detonators.[1] Common primer mixes, such as NOL-130, are made up of lead styphnate (basic) 40%, lead azide (dextrinated) 20%, barium nitrate 20%, antimony sulfide 15%, and tetrazene 5%.[1] These materials pose acute and chronic toxicity hazards during mixing of the composition and later in the item life cycle after the item has been field functioned. There is an established need to replace these mixes on toxicity, health, and environmental hazard grounds. This effort attempts to demonstrate that environmentally acceptable energetic solgel coated flash metal multilayer nanocomposites can be used to replace current impact initiated devices (IIDs), which have hazardous and toxic components. Successful completion of this project will result in IIDs that include innocuous compounds, have sufficient output energy for initiation, meet current military specifications, are small, cost competitive, and perform as well as or better than current devices. We expect flash

  18. Application of full-face round by the sequential blasting machine in tunnel excavation

    SciTech Connect

    Cho, Y.D.; Park, B.K.; Lee, S.E.; Lim, H.U.

    1995-12-31

    Many methods and techniques have been developed to reduce ground vibrations. Some of them are an adoption of electric millisecond detonators with a sequential blasting machine and an improvement of initiating system with an adequate number of delay intervals. To reduce the level of ground vibration in tunnel excavation, the sequential blasting machine (S.B.M.) with decisecond detonators was adopted. A total of 134 blasts was recorded at various sites and the results were analyzed. The distances blast-to-structures were ranged from 20.3 to 42.0 meter, where charge weights were varied from 0.25 to 0.75kg per delay. It is proved that the sequential blasting in tunnel excavation is very effective to control ground vibration.

  19. A review of direct numerical simulations of astrophysical detonations and their implications

    NASA Astrophysics Data System (ADS)

    Parete-Koon, Suzanne T.; Smith, Christopher R.; Papatheodore, Thomas L.; Messer, O. E. Bronson

    2013-04-01

    Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use onedimensional DNS of detonations as inputs or constraints for their whole star simulations.While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerable effort has been expended modeling Type Ia supernovae at densities above 1×107 g·cm-3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1×107 g·cm-3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. This work will review the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.

  20. A review of direct numerical simulations of astrophysical detonations and their implications

    DOE PAGESBeta

    Parete-Koon, Suzanne T.; Smith, Christopher R.; Papatheodore, Thomas L.; Bronson Messer, O. E.

    2013-04-11

    Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerablemore » effort has been expended modeling Type Ia supernovae at densities above 1x107 g∙cm-3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1x107 g∙cm-3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. In conclusion, this work reviews the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.« less

  1. Miniature plasma accelerating detonator and method of detonating insensitive materials

    DOEpatents

    Bickes, R.W. Jr.; Kopczewski, M.R.; Schwarz, A.C.

    1985-01-04

    The invention is a detonator for use with high explosives. The detonator comprises a pair of parallel rail electrodes connected to a power supply. By shorting the electrodes at one end, a plasma is generated and accelerated toward the other end to impact against explosives. A projectile can be arranged between the rails to be accelerated by the plasma. An alternative arrangement is to a coaxial electrode construction. The invention also relates to a method of detonating explosives. 3 figs.

  2. Miniature plasma accelerating detonator and method of detonating insensitive materials

    DOEpatents

    Bickes, Jr., Robert W.; Kopczewski, Michael R.; Schwarz, Alfred C.

    1986-01-01

    The invention is a detonator for use with high explosives. The detonator comprises a pair of parallel rail electrodes connected to a power supply. By shorting the electrodes at one end, a plasma is generated and accelerated toward the other end to impact against explosives. A projectile can be arranged between the rails to be accelerated by the plasma. An alternative arrangement is to a coaxial electrode construction. The invention also relates to a method of detonating explosives.

  3. Chemical Equilibrium Detonation

    NASA Astrophysics Data System (ADS)

    Bastea, Sorin; Fried, Laurence E.

    Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. The fundamental principles outlined in this chapter pertain to the study of detonation in both gas-phase and condensed-phase energetic materials, but our main focus will be on the condensed ones, particularly on high explosives (HEs). They share many properties with other classes of condensed energetic compounds such as propellants and pyrotechnics, but a detailed understanding of detonation is especially important for numerous HE applications. The usage and study of HE materials goes back more than a century, but many questions remain to be answered, e.g., on their reaction pathways at high pressures and temperatures, chemical properties, etc.

  4. Recent work on gaseous detonations

    NASA Astrophysics Data System (ADS)

    Nettleton, M. A.

    The paper reviews recent progress in the field of gaseous detonations, with sections on shock diffraction and reflection, the transition to detonation, hybrid, spherically-imploding, and galloping and stuttering fronts, their structure, their transmission and quenching by additives, the critical energy for initiation and detonation of more unusual fuels. The final section points out areas where our understanding is still far from being complete and contains some suggestions of ways in which progress might be made.

  5. Low voltage nonprimary explosive detonator

    DOEpatents

    Dinegar, Robert H.; Kirkham, John

    1982-01-01

    A low voltage, electrically actuated, nonprimary explosive detonator is disclosed wherein said detonation is achieved by means of an explosive train in which a deflagration-to-detonation transition is made to occur. The explosive train is confined within a cylindrical body and positioned adjacent to low voltage ignition means have electrical leads extending outwardly from the cylindrical confining body. Application of a low voltage current to the electrical leads ignites a self-sustained deflagration in a donor portion of the explosive train which then is made to undergo a transition to detonation further down the train.

  6. Percussive Excavation of Lunar Soil

    NASA Technical Reports Server (NTRS)

    Whittaker, Matthew P.

    2008-01-01

    It has been suggested using a percussive motion could improve the efficiency of excavation by up to 90%. If this is proven to be true it would be very beneficial to excavation projects on the Moon and Mars. The purpose of this study is to design, build and test a percussive tool which could dig a trench and then compare this data against that of a non-percussive tool of the same shape and size. The results of this test thus far have been inconclusive due to malfunctions in the testbed and percussive bucket; however, experimental results from small scale experiments confirm this higher efficiency and support further testing.

  7. Detonation charge size versus coda magnitude relations in California and Nevada

    USGS Publications Warehouse

    Brocher, T.M.

    2003-01-01

    Magnitude-charge size relations have important uses in forensic seismology and are used in Comprehensive Nuclear-Test-Ban Treaty monitoring. I derive empirical magnitude versus detonation-charge-size relationships for 322 detonations located by permanent seismic networks in California and Nevada. These detonations, used in 41 different seismic refraction or network calibration experiments, ranged in yield (charge size) between 25 and 106 kg; coda magnitudes reported for them ranged from 0.5 to 3.9. Almost all represent simultaneous (single-fired) detonations of one or more boreholes. Repeated detonations at the same shotpoint suggest that the reported coda magnitudes are repeatable, on average, to within 0.1 magnitude unit. An empirical linear regression for these 322 detonations yields M = 0.31 + 0.50 log10(weight [kg]). The detonations compiled here demonstrate that the Khalturin et al. (1998) relationship, developed mainly for data from large chemical explosions but which fits data from nuclear blasts, can be used to estimate the minimum charge size for coda magnitudes between 0.5 and 3.9. Drilling, loading, and shooting logs indicate that the explosive specification, loading method, and effectiveness of tamp are the primary factors determining the efficiency of a detonation. These records indicate that locating a detonation within the water table is neither a necessary nor sufficient condition for an efficient shot.

  8. Pulse detonation MHD power

    SciTech Connect

    Litchford, R.J.; Thompson, B.R.; Lineberry, J.T.

    1998-07-01

    A series of laboratory scale experiments were conducted to investigate the basic engineering performance characteristics of a pulse detonation driven magnetohydrodynamic electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium-hydroxide/ methanol spray were detonated at atmospheric pressure in a 1 m long tube having an inside diameter of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p{sub 2}/p{sub 1} {approximately} 34 and D {approximately} 2400 m/s) and enabled the measurement of current density ({approximately} 2 A/cm{sup 2}) and electrical conductivity ({approximately} 6 mho/m) behind the detonation wave front. In a second set of experiments, a 30 cm long continuous electrode Faraday channel having a height of 2.54 cm and a width of 2.0 cm was attached to the end of the tube using an area transition duct. The Faraday channel was placed inside a permanent magnet assembly having a nominal magnetic induction of 0.6 Tesla, and the electrodes were connected to an active loading circuit in order to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. In these single-shot experiments, the near-electrode potential drop was found to consume approximately 60% of the effective u x B induced potential. For B = 0.6 Tesla, the authors obtained a peak open circuit voltage of V{sub O}C = Bh {approximately} 10 volts implying an effective burned gas velocity relative to the tube of {approximately} 660 m/s which may be compared with the theoretical equilibrium value for the idealized case (1100 m/s). The experiments indicated peak power extraction at a load impedance between 5 and 10 Ohms. The measured peak electrical energy density ranged from 10 to 10{sup 3} J/m{sup 3} when the effective magnetic induction was varied from 0.6 to 4.2 Tesla. These results

  9. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  10. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, R.W. Jr.; Grubelich, M.C.

    1999-01-19

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

  11. Pulse Detonation Engine Modeled

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2001-01-01

    Pulse Detonation Engine Technology is currently being investigated at Glenn for both airbreathing and rocket propulsion applications. The potential for both mechanical simplicity and high efficiency due to the inherent near-constant-volume combustion process, may make Pulse Detonation Engines (PDE's) well suited for a number of mission profiles. Assessment of PDE cycles requires a simulation capability that is both fast and accurate. It should capture the essential physics of the system, yet run at speeds that allow parametric analysis. A quasi-one-dimensional, computational-fluid-dynamics-based simulation has been developed that may meet these requirements. The Euler equations of mass, momentum, and energy have been used along with a single reactive species transport equation, and submodels to account for dominant loss mechanisms (e.g., viscous losses, heat transfer, and valving) to successfully simulate PDE cycles. A high-resolution numerical integration scheme was chosen to capture the discontinuities associated with detonation, and robust boundary condition procedures were incorporated to accommodate flow reversals that may arise during a given cycle. The accompanying graphs compare experimentally measured and computed performance over a range of operating conditions for a particular PDE. Experimental data were supplied by Fred Schauer and Jeff Stutrud from the Air Force Research Laboratory at Wright-Patterson AFB and by Royce Bradley from Innovative Scientific Solutions, Inc. The left graph shows thrust and specific impulse, Isp, as functions of equivalence ratio for a PDE cycle in which the tube is completely filled with a detonable hydrogen/air mixture. The right graph shows thrust and specific impulse as functions of the fraction of the tube that is filled with a stoichiometric mixture of hydrogen and air. For both figures, the operating frequency was 16 Hz. The agreement between measured and computed values is quite good, both in terms of trend and

  12. Detonation diffraction in gases

    SciTech Connect

    Pintgen, F.; Shepherd, J.E.

    2009-03-15

    We have experimentally investigated detonation diffraction out of a round tube into an unconfined half-space. The focus of our study is examining how the extent of detonation cellular instability influences the quantitative and qualitative features of diffraction. Detailed quantitative and qualitative measurements were obtained through simultaneous schlieren imaging, multiple-exposure chemiluminescence imaging, and planar laser-induced fluorescence imaging of OH molecules. Two types of stoichiometric mixtures, highly diluted H{sub 2}-O{sub 2}-Ar and H{sub 2}-N{sub 2}O, were studied in the sub-critical, critical and super-critical regime. These mixture types represent extreme cases in the classification of cellular instability with highly diluted H{sub 2}-O{sub 2}-Ar mixtures having very regular instability structures and H{sub 2}-N{sub 2}O having very irregular instability structures. The most striking differences between the mixtures occur in the sub-critical and critical regimes, for which the detonation fails to transition into the unconfined half-space. For the H{sub 2}-O{sub 2}-Ar mixture, the velocity on the center line was found to decay significantly slower than for the H{sub 2}-N{sub 2}O mixture. In case of the H{sub 2}-O{sub 2}-Ar mixture, it was evident from simultaneous schlieren-fluorescence images that the reaction front was coupled to the lead shock front up to 2.3 tube diameters from the exit plane. For the H{sub 2}-N{sub 2}O mixture, the reaction front velocity decreased to 60% of the corresponding Chapman-Jouguet value at 1.1 tube diameters from the tube exit plane. A geometric acoustic model showed that the observed differences in failure patterns are not caused by the differences in thermodynamic properties of the two mixtures but is linked to the larger effective activation energy and critical decay time in the H{sub 2}-N{sub 2}O mixture as compared to the H{sub 2}-O{sub 2}-Ar mixture. The re-initiation events appear similar for the two

  13. Detonator-activated ball shutter

    DOEpatents

    McWilliams, Roy A.; von Holle, William G.

    1983-01-01

    A detonator-activated ball shutter for closing an aperture in about 300.mu. seconds. The ball shutter containing an aperture through which light, etc., passes, is closed by firing a detonator which propels a projectile for rotating the ball shutter, thereby blocking passage through the aperture.

  14. Detonator-activated ball shutter

    DOEpatents

    McWilliams, R.A.; Holle, W.G. von.

    1983-08-16

    A detonator-activated ball shutter for closing an aperture in about 300[mu] seconds. The ball shutter containing an aperture through which light, etc., passes, is closed by firing a detonator which propels a projectile for rotating the ball shutter, thereby blocking passage through the aperture. 3 figs.

  15. Planar Reflection of Detonations Waves

    NASA Astrophysics Data System (ADS)

    Damazo, Jason; Shepherd, Joseph

    2012-11-01

    An experimental study examining normally reflected gaseous detonation waves is undertaken so that the physics of reflected detonations may be understood. Focused schlieren visualization is used to describe the boundary layer development behind the incident detonation wave and the nature of the reflected shock wave. Reflected shock wave bifurcation-which has received extensive study as it pertains to shock tube performance-is predicted by classical bifurcation theory, but is not observed in the present study for undiluted hydrogen-oxygen and ethylene-oxygen detonation waves. Pressure and thermocouple gauges are installed in the floor of the detonation tube so as to examine both the wall pressure and heat flux. From the pressure results, we observe an inconsistency between the measured reflected shock speed and the measured reflected shock strength with one dimensional flow predictions confirming earlier experiments performed in our laboratory. This research is sponsored by the DHS through the University of Rhode Island, Center of Excellence for Explosives Detection.

  16. Assessment of Blasting Performance Using Electronic Vis-à-Vis Shock Tube Detonators in Strong Garnet Biotite Sillimanite Gneiss Formations

    NASA Astrophysics Data System (ADS)

    Sharma, Suresh Kumar; Rai, Piyush

    2016-04-01

    This paper presents a comparative investigation of the shock tube and electronic detonating systems practised in bench blasting. The blast trials were conducted on overburden rocks of Garnet Biotite Sillimanite Gneiss formations in one of the largest metalliferous mine of India. The study revealed that the choice of detonating system was crucial in deciding the fragment size and its distribution within the blasted muck-piles. The fragment size and its distribution affected the digging rate of excavators. Also, the shape of the blasted muck-pile was found to be related to the degree of fragmentation. From the present work, it may be inferred that in electronic detonation system, timely release of explosive energy resulted in better overall blasting performance. Hence, the precision in delay time must be considered in designing blast rounds in such overburden rock formations. State-of-art image analysis, GPS based muck-pile profile plotting techniques were rigorously used in the investigation. The study revealed that a mean fragment size (K50) value for shock tube detonated blasts (0.55-0.59 m) was higher than that of electronically detonated blasts (0.43-0.45 m). The digging rate of designated shovels (34 m3) with electronically detonated blasts was consistently more than 5000 t/h, which was almost 13 % higher in comparison to shock tube detonated blasts. Furthermore, favourable muck-pile shapes were witnessed in electronically detonated blasts from the observations made on the dozer performance.

  17. Planar Reflection of Gaseous Detonations

    NASA Astrophysics Data System (ADS)

    Damazo, Jason Scott

    Pipes containing flammable gaseous mixtures may be subjected to internal detonation. When the detonation normally impinges on a closed end, a reflected shock wave is created to bring the flow back to rest. This study built on the work of Karnesky (2010) and examined deformation of thin-walled stainless steel tubes subjected to internal reflected gaseous detonations. A ripple pattern was observed in the tube wall for certain fill pressures, and a criterion was developed that predicted when the ripple pattern would form. A two-dimensional finite element analysis was performed using Johnson-Cook material properties; the pressure loading created by reflected gaseous detonations was accounted for with a previously developed pressure model. The residual plastic strain between experiments and computations was in good agreement. During the examination of detonation-driven deformation, discrepancies were discovered in our understanding of reflected gaseous detonation behavior. Previous models did not accurately describe the nature of the reflected shock wave, which motivated further experiments in a detonation tube with optical access. Pressure sensors and schlieren images were used to examine reflected shock behavior, and it was determined that the discrepancies were related to the reaction zone thickness extant behind the detonation front. During these experiments reflected shock bifurcation did not appear to occur, but the unfocused visualization system made certainty impossible. This prompted construction of a focused schlieren system that investigated possible shock wave-boundary layer interaction, and heat-flux gauges analyzed the boundary layer behind the detonation front. Using these data with an analytical boundary layer solution, it was determined that the strong thermal boundary layer present behind the detonation front inhibits the development of reflected shock wave bifurcation.

  18. Remote Excavation System test plan

    SciTech Connect

    Walker, S.; Hyde, R.A.

    1993-05-01

    The Office of Technology Development (OTD) established the Robotics Technology Development Program (RTDP) to integrate robotic development activities on a national basis; provide needs-oriented, timely, and economical robotics technology to support environmental and waste operations activities at Department of Energy (DOE) sites; and provide the focus and direction for the near term (less than five years) and guidance for the tong-term (five to twenty years) research and development efforts for site-specific problems. The RTDP consists of several programs including the Buried Waste Robotics Program (BWRP), which addresses remote buried waste applications. The Remote Excavation System (RES) was developed under the RTDP to provide a safer method of excavating hazardous materials for both the DOE and the Department of Defense (DOD). The excavator, initially developed by the DOD as a manually-operated small excavator, has been modified for teleoperation with joint funding from the BWRP and the DOD. The Buried Waste Integrated Demonstration (BWID) and the Uranium Soils Integrated Demonstration (USID) are funding the demonstration, testing, and evaluation of the RES covered in this test plan. This document covers testing both at Oak Ridge National Laboratory (ORNL) and the Idaho National Engineering Laboratory (INEL), as funded by BWID and USID. This document describes the tests planned for the RES demonstration for the BWRP. The purposes of the test plan are (1) to establish test parameters to ensure that the demonstration results are deemed useful and usable and (2) to demonstrate performance in a safe manner within all regulatory requirements.

  19. Detonation spreading in fine TATBs

    SciTech Connect

    Kennedy, J.E.; Lee, K.Y.; Spontarelli, T.; Stine, J.R.

    1998-12-31

    A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.

  20. Preparation of C60 by Detonation Technique

    NASA Astrophysics Data System (ADS)

    Wei, Xianfeng; Han, Yong; Long, Xinping

    2012-11-01

    A mixture of TNT (Trinitrotoluene) and natural graphite was detonated in a vacuum container which was immersed into cooling water; detonation products were collected for detecting. The results of mass spectroscopy, high performance liquid chromatography showed significant signals of C60, which proved that C60 could be synthesized by detonating the mixture of TNT/graphite and the detonation pressure was around 12.3 GPa and the detonation temperature was around 1985 K.

  1. Two phase detonation studies

    NASA Technical Reports Server (NTRS)

    Nicholls, J. A.; Pierce, T. H.; Miyajima, H.; Oza, R.; Patil, P.

    1974-01-01

    An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant.

  2. New generation detonics

    SciTech Connect

    Souers, P.C.

    1996-12-15

    Modern theory is being used to accelerate the development of new high performance explosive molecules. Combining quantum chemistry calculations with synthesis of promising candidate molecules may enable the advance of the state of the art in this field by more than 50 years. We have established a high explosive performance prediction code by linking the thermochemical code CHEETAH with the ab initio electronic structure code GAUSSIAN and the molecular packing code MOLPAK. GAUSSIAN is first used to determine the shape of the molecule and its binding energy; the molecules are then packed together into a low energy configuration by MOLPAK. Finally, CHEETAH is used to transform the crystal energy and density into explosive performance measures such as detonation velocity, pressure, and energy. Over 70 target molecules have been created, and several of these show promise in combining performance, chemical stability, and ease of synthesis.

  3. Transplutonium elements processed from rock debris of underground detonations

    NASA Technical Reports Server (NTRS)

    Bloomquist, C. A. A.; Harvey, H. W.; Hoh, J. C.; Horwitz, E. P.

    1969-01-01

    Six-step chemical processing method extracts minute quantities of transplutonium elements found in rock debris following a nuclear detonation. The process consists of dissolution of rock, feed preparation, liquid-liquid extraction, final purification of transplutonium elements and plutonium, and separation of the transplutonium elements.

  4. Lunar Excavator Preliminary Test Video

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This video shows a preliminary test of the boom and bucket wheel assembly of the lunar excavator prototype developed by the Center for Commercial Applications of Combustion at the Colorado School of Mines in Golden. According to Michael Duke, director for the center, the wheel on the end of the boom can dig up 45.36 kilograms (100 pounds) of dirt each hour which is several times the weight of the entire device.

  5. Reduce costs with vacuum excavation

    SciTech Connect

    Vitale, S.A.

    1983-09-01

    Although vacuum excavation equipment and methods are in their infancy, this developing technology offers tremendous promise for the future. The author explains Brooklyn Union Gas Co.'s experience with five vacuum trucks and the procedures that are used. In recent years, the higher cost of natural gas has increased the need for gas utilities to reduce their operating expenses. One way, which has been successful at Brooklyn Union Gas, is the use of vacuum excavation. Although vacuum excavation equipment and techniques are in their infancy, this developing technology offers substantial savings today and tremendous promise for the future. Brooklyn Union started its vacuum digging program by locating keyhole cutoffs--small surface openings ranging from 1 ft by 1 ft to 1 1/2 ft by 1 1/2 ft (0.3 m to 0.45 m square). It is no easy task to accurately locate a service that was installed 60 years ago. Reading the street indications, locating an existing curb valve or repair opening, gaining access to the building, making a physical lineup, and using an M-scope, plus any other tools available, have produced a high success rate.

  6. Hemodynamics of focal choroidal excavations.

    PubMed

    Soma, Ryoko; Moriyama, Muka; Ohno-Matsui, Kyoko

    2015-04-01

    The purpose of this study was to investigate the hemodynamics of focal choroidal excavations (FCEs). Four eyes of four patients with a FCE were studied. Indocyanine green angiography (ICGA), laser speckle flowgraphy (LSFG), optical coherence tomography (OCT), and multi-focal electroretinography (mfERG) were performed to investigate the choroidal hemodynamics and the morphological and functional changes. The mean depth of the FCE determined by OCT was 222.5 ± 49.5 μm with a range of 164-272 μm. In one case, subretinal fluid was observed in the excavation, and in three cases, subretinal fluid was not observed. ICGA showed hypofluorescence, and laser flowgraphy (LSFG) showed decreased choroidal blood flow at the excavation in all cases. Three cases were symptomatic, and the amplitudes of the mfERGs were reduced. FCEs cause a decrease of choroidal blood flow. In three of four cases, the mfERGs were depressed over the FCEs leading to symptoms. PMID:25626897

  7. CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect

    Holcomb, Cole; Guillochon, James; De Colle, Fabio; Ramirez-Ruiz, Enrico

    2013-07-01

    Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range between 1 and 10{sup 10} cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of {approx}100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M{sub Sun} can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that {sup 40}Ca, {sup 44}Ti, or {sup 48}Cr, rather than {sup 56}Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and {sup 56}Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.

  8. Telemanipulation and supervisory control of a backhoe excavator

    NASA Astrophysics Data System (ADS)

    Luengo, Oscar; Barrientos, Antonio

    1998-12-01

    The excavation tasks present one of the more challenging area in robotic research. The environment is highly unstructured, the forces that appear are very large it is very important the detection of underground obstacles to avoid any damage, and the modeling of the hydraulic actuators is highly nonlinear. In recent years, the remote control of the excavation has found applications in very dangerous environments for human beings, like nuclear power plants, nuclear and chemical waste facilities and terrestrial and extra-terrestrial mining. Some kind of intelligence is required due to the presence of unexpected situations. The first approach to deal with the problem is to put a human being in the loop, that is: teleoperation. The next step towards the total automation of the excavation is the supervisory control of the task. In this scheme, the operator acts like a supervisor, providing high level commands, and checking the development and accomplishment of the task. The solutions that DISAM has developed are presented in this paper, as well as future work that will be very useful in the search for the total automation of excavation tasks.

  9. Double-Front Detonation Waves

    NASA Astrophysics Data System (ADS)

    Gubin, S. A.; Sumskoi, S. I.; Victorov, S. B.

    According to the theory of detonation, in a detonation wave there is a sound plane, named Chapman-Jouguet (CJ) plane. There are certain stationary parameters for this plane. In this work the possibility of the second CJ plane is shown. This second CJ plane is stationary as well. The physical mechanism of non-equilibrium transition providing the existence of the second CJ plane is presented. There is a non-equilibrium state, when the heat is removed from the reaction zone and the heat capacity decreases sharply. As a result of this non-equilibrium state, the sound velocity increases, and the local supersonic zone with second sonic plane (second CJ plane) appears. So the new mode of detonation wave is predicted. Equations describing this mode of detonation are presented. The exact analytical solution for the second CJ plane parameters is obtained. The example of double-front detonation in high explosive (TNT) is presented. In this double-front structure "nanodiamond-nanographite" phase transition takes place in condensed particles of detonation products.

  10. 29 CFR 1926.908 - Use of detonating cord.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... kinks, or angles that direct the cord back toward the oncoming line of detonation. (g) All detonating... direction in which the detonation is to proceed. (j) Detonators for firing the trunkline shall not...

  11. Detonation in TATB Hemispheres

    SciTech Connect

    Druce, B; Souers, P C; Chow, C; Roeske, F; Vitello, P; Hrousis, C

    2004-03-17

    Streak camera breakout and Fabry-Perot interferometer data have been taken on the outer surface of 1.80 g/cm{sup 3} TATB hemispherical boosters initiated by slapper detonators at three temperatures. The slapper causes breakout to occur at 54{sup o} at ambient temperatures and 42{sup o} at -54 C, where the axis of rotation is 0{sup o}. The Fabry velocities may be associated with pressures, and these decrease for large timing delays in breakout seen at the colder temperatures. At room temperature, the Fabry pressures appear constant at all angles. Both fresh and decade-old explosive are tested and no difference is seen. The problem has been modeled with reactive flow. Adjustment of the JWL for temperature makes little difference, but cooling to -54 C decreases the rate constant by 1/6th. The problem was run both at constant density and with density differences using two different codes. The ambient code results show that a density difference is probably there but it cannot be quantified.

  12. Zero Horizontal Reaction Force Excavator

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P. (Inventor); Nick, Andrew J. (Inventor); Schuler, Jason M. (Inventor); Smith, Jonathan D. (Inventor)

    2015-01-01

    An excavator includes a mobile chassis with a first bucket drum and a second bucket drum coupled thereto. The first bucket drum and second bucket drum are coupled to the chassis for positioning thereof on the surface at opposing ends of the chassis. Each first scoop on the first bucket drum is a mirror image of one second scoop on the second bucket drum when (i) the first bucket drum and second bucket drum are on the surface adjacent opposing ends of the chassis, and (ii) the first bucket drum is rotated in one direction and the second bucket drum is simultaneously rotated in an opposing direction.

  13. A review of direct numerical simulations of astrophysical detonations and their implications

    SciTech Connect

    Parete-Koon, Suzanne T.; Smith, Christopher R.; Papatheodore, Thomas L.; Bronson Messer, O. E.

    2013-04-11

    Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerable effort has been expended modeling Type Ia supernovae at densities above 1x107 g∙cm-3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1x107 g∙cm-3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. In conclusion, this work reviews the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.

  14. Stability of cosmological detonation fronts

    NASA Astrophysics Data System (ADS)

    Mégevand, Ariel; Membiela, Federico Agustín

    2014-05-01

    The steady-state propagation of a phase-transition front is classified, according to hydrodynamics, as a deflagration or a detonation, depending on its velocity with respect to the fluid. These propagation modes are further divided into three types, namely, weak, Jouguet, and strong solutions, according to their disturbance of the fluid. However, some of these hydrodynamic modes will not be realized in a phase transition. One particular cause is the presence of instabilities. In this work we study the linear stability of weak detonations, which are generally believed to be stable. After discussing in detail the weak detonation solution, we consider small perturbations of the interface and the fluid configuration. When the balance between the driving and friction forces is taken into account, it turns out that there are actually two different kinds of weak detonations, which behave very differently as functions of the parameters. We show that the branch of stronger weak detonations are unstable, except very close to the Jouguet point, where our approach breaks down.

  15. DETONATION PRESSURE MEASUREMENTS ON PETN

    SciTech Connect

    Green, L G; Lee, E L

    2006-06-23

    PETN is widely recognized as an example of nearly ideal detonation performance. The chemical composition is such that little or no carbon is produced in the detonation products. The reaction zone width is less than currently detectable. (<1 ns) Observations on PETN have thus become a baseline for EOS model predictions. It has therefore become important to characterize the detonation parameters as accurately as possible in order to provide the most exacting comparisons of EOS predictions with experimental results. We undertook a painstaking review of the detonation pressure measurements reported in an earlier work that was presented at the Fifth Detonation Symposium and found that corrections were required in determining the shock velocity in the PMMA witness material. We also refined the impedance calculation to account for the difference between the usual ''acoustic'' method and the more accurate Riemann integral. Our review indicates that the CJ pressures previously reported for full density PETN require an average lowering of about 6 percent. The lower densities require progressively smaller corrections. We present analysis of the records, supporting hydrodynamic simulations, the Riemann integral results, and EOS parameter values derived from the revised results.

  16. Point Measurement of Detonation Wave Speed

    NASA Astrophysics Data System (ADS)

    Lu, F. K.; Gupta, N. K. M.; Wilson, D. R.

    Accurate determination of the speed of a detonation wave is important for studies of detonation phenomena. Different types of sensors that measure pressure, ion and flame have been used for this purpose.

  17. Mechanical tunnel excavation in welded tuff

    SciTech Connect

    Sperry, P.E.

    1991-12-31

    The Technical Review Board for the US high-level radioactive waste facility at Yucca Mountain has recommended maximum use of {open_quotes}the most modern mechanical excavation techniques...in order to reduce disturbance to the rock walls and to achieve greater economy of time and cost.{close_quotes} Tunnels for the waste repository at Yucca Mountain can be economically constructed with mechanical excavation equipment. This paper presents the results of mechanical excavation of a tunnel in welded tuff, similar to the tuffs of Yucca Mountain. These results are projected to excavation of emplacement drifts in Yucca Mountain using a current state-of-the-art tunnel boring machine (TBM).

  18. Equation of state for detonation products. [Detonation products

    SciTech Connect

    Davis, W.C.

    1985-01-01

    The concepts of hydrodynamics and thermodynamics as they apply to equations of state for explosive products are collected and discussed. The physics behind the behavior of dense gases is considered. Some ideas about applications are presented. This paper is intended as an introduction to the subject of equation of state for detonation products. 7 references, 3 figures.

  19. Toxic hazards of underground excavation

    SciTech Connect

    Smith, R.; Chitnis, V.; Damasian, M.; Lemm, M.; Popplesdorf, N.; Ryan, T.; Saban, C.; Cohen, J.; Smith, C.; Ciminesi, F.

    1982-09-01

    Inadvertent intrusion into natural or man-made toxic or hazardous material deposits as a consequence of activities such as mining, excavation or tunnelling has resulted in numerous deaths and injuries in this country. This study is a preliminary investigation to identify and document instances of such fatal or injurious intrusion. An objective is to provide useful insights and information related to potential hazards due to future intrusion into underground radioactive-waste-disposal facilities. The methodology used in this study includes literature review and correspondence with appropriate government agencies and organizations. Key categories of intrusion hazards are asphyxiation, methane, hydrogen sulfide, silica and asbestos, naturally occurring radionuclides, and various mine or waste dump related hazards.

  20. Environmentally Benign Stab Detonators

    SciTech Connect

    Gash, A E

    2006-07-07

    The coupling of energetic metallic multilayers (a.k.a. flash metal) with energetic sol-gel synthesis and processing is an entirely new approach to forming energetic devices for several DoD and DOE needs. They are also practical and commercially viable manufacturing techniques. Improved occupational safety and health, performance, reliability, reproducibility, and environmentally acceptable processing can be achieved using these methodologies and materials. The development and fielding of this technology will enhance mission readiness and reduce the costs, environmental risks and the necessity of resolving environmental concerns related to maintaining military readiness while simultaneously enhancing safety and health. Without sacrificing current performance, we will formulate new impact initiated device (IID) compositions to replace materials from the current composition that pose significant environmental, health, and safety problems associated with functions such as synthesis, material receipt, storage, handling, processing into the composition, reaction products from testing, and safe disposal. To do this, we will advance the use of nanocomposite preparation via the use of multilayer flash metal and sol-gel technologies and apply it to new small IIDs. This work will also serve to demonstrate that these technologies and resultant materials are relevant and practical to a variety of energetic needs of DoD and DOE. The goal will be to produce an IID whose composition is acceptable by OSHA, EPA, the Clean Air Act, Clean Water Act, Resource Recovery Act, etc. standards, without sacrificing current performance. The development of environmentally benign stab detonators and igniters will result in the removal of hazardous and toxic components associated with their manufacturing, handling, and use. This will lead to improved worker safety during manufacturing as well as reduced exposure of Service personnel during their storage and or use in operations. The

  1. Archaeology Excavation Simulation: Correcting the Emphasis

    ERIC Educational Resources Information Center

    Thistle, Paul C.

    2012-01-01

    Museums offering archaeological programs often attempt to use the "sandbox approach" to simulate archaeological excavation work. However, in light of the definition of simulation, and given the realities of actual professional practice in archaeological excavation, the author argues that the activity of troweling for artifacts in loose sand places…

  2. Regolith Advanced Surface Systems Operations Robot Excavator

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.; Smith, Jonathan D.; Ebert, Thomas; Cox, Rachel; Rahmatian, Laila; Wood, James; Schuler, Jason; Nick, Andrew

    2013-01-01

    The Regolith Advanced Surface Systems Operations Robot (RASSOR) excavator robot is a teleoperated mobility platform with a space regolith excavation capability. This more compact, lightweight design (<50 kg) has counterrotating bucket drums, which results in a net-zero reaction horizontal force due to the self-cancellation of the symmetrical, equal but opposing, digging forces.

  3. Indirect pulp therapy and stepwise excavation.

    PubMed

    Bjørndal, Lars

    2008-01-01

    Various treatment concepts have been suggested to solve the deep carious lesion dilemma. Recent systematic reviews are presented. Their conclusions are based on very few studies, and the main message is that optimal randomized clinical studies are lacking. Observational studies on indirect pulp treatment and stepwise excavation demonstrate that these treatments avoid pulp exposures, but it cannot be said which approach is best. A less invasive modified stepwise excavation approach is described, focusing on changing on active lesion into on arrested lesion even without performing an excavation close to the pulp. In Denmark and Sweden a randomized clinical multi-center trial is currently taking place, the Caries and Pulp (CAP) trial. This trial is investigating the effects of stepwise excavation over 2 visits versus 1 complete excavation of deep caries in permanent teeth. Guidelines for treatment are presented. PMID:18615988

  4. Indirect pulp therapy and stepwise excavation.

    PubMed

    Bjørndal, Lars

    2008-07-01

    Various treatment concepts have been suggested to solve the deep carious lesion dilemma. Recent systematic reviews are presented. Their conclusions are based on very few studies, and the main message is that optimal randomized clinical studies are lacking. Observational studies on indirect pulp treatment and stepwise excavation demonstrate that these treatments avoid pulp exposures, but it cannot be said which approach is best. A less invasive modified stepwise excavation approach is described, focusing on changing an active lesion into an arrested lesion even without performing an excavation close to the pulp. In Denmark and Sweden a randomized clinical multi-center trial is currently taking place, the Caries and Pulp (CAP) trial. This trial is investigating the effects of stepwise excavation over 2 visits versus 1 complete excavation of deep caries in permanent teeth. Guidelines for treatment are presented. PMID:18565369

  5. Detonation waves in relativistic hydrodynamics

    SciTech Connect

    Cissoko, M. )

    1992-02-15

    This paper is concerned with an algebraic study of the equations of detonation waves in relativistic hydrodynamics taking into account the pressure and the energy of thermal radiation. A new approach to shock and detonation wavefronts is outlined. The fluid under consideration is assumed to be perfect (nonviscous and nonconducting) and to obey the following equation of state: {ital p}=({gamma}{minus}1){rho} where {ital p}, {rho}, and {gamma} are the pressure, the total energy density, and the adiabatic index, respectively. The solutions of the equations of detonation waves are reduced to the problem of finding physically acceptable roots of a quadratic polynomial {Pi}({ital X}) where {ital X} is the ratio {tau}/{tau}{sub 0} of dynamical volumes behind and ahead of the detonation wave. The existence and the locations of zeros of this polynomial allow it to be shown that if the equation of state of the burnt fluid is known then the variables characterizing the unburnt fluid obey well-defined physical relations.

  6. Airbreathing Pulse Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.; Yungster, Shaye

    2002-01-01

    This paper presents performance results for pulse detonation engines (PDE) taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

  7. Airbreathing Pulse Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.; Yungster, Shaye

    2002-01-01

    This paper presents performance results for pulse detonation engines taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

  8. Vapor phase explosions: elementary detonations?

    PubMed

    Fowles, G R

    1979-04-13

    Although liquid-vapor explosions are widely observed, there is no established explanation for their initiation and propagation. Thermodynamics admits the possibility that superheated liquids can support detonations analogous to those that occur in chemical explosives. For liquid methane superheated 50 K above its boiling point at 1 atmosphere, the energy of explosion is 2 to 3 percent of that of TNT. PMID:17738085

  9. Sensitized Liquid Hydrazine Detonation Studies

    NASA Technical Reports Server (NTRS)

    Rathgeber, K. A.; Keddy, C. P.; Bunker, R. L.

    1999-01-01

    Vapor-phase hydrazine (N2H4) is known to be very sensitive to detonation while liquid hydrazine is very insensitive to detonation, theoretically requiring extremely high pressures to induce initiation. A review of literature on solid and liquid explosives shows that when pure explosive substances are infiltrated with gas cavities, voids, and/or different phase contaminants, the energy or shock pressure necessary to induce detonation can decrease by an order of magnitude. Tests were conducted with liquid hydrazine in a modified card-gap configuration. Sensitization was attempted by bubbling helium gas through and/or suspending ceramic microspheres in the liquid. The hydrazine was subjected to the shock pressure from a 2 lb (0.9 kg) Composition C-4 explosive charge. The hydrazine was contained in a 4 in. (10.2 cm) diameter stainless steel cylinder with a 122 in(sup 3) (2 L) volume and sealed with a polyethylene cap. Blast pressures from the events were recorded by 63 high speed pressure transducers located on three radial legs extending from 4 to 115 ft (1.2 to 35.1 in) from ground zero. Comparison of the neat hydrazine and water baseline tests with the "sensitized" hydrazine tests indicates the liquid hydrazine did not detonate under these conditions.

  10. Pulse detonation engines and components thereof

    NASA Technical Reports Server (NTRS)

    Tangirala, Venkat Eswarlu (Inventor); Rasheed, Adam (Inventor); Vandervort, Christian Lee (Inventor); Dean, Anthony John (Inventor)

    2009-01-01

    A pulse detonation engine comprises a primary air inlet; a primary air plenum located in fluid communication with the primary air inlet; a secondary air inlet; a secondary air plenum located in fluid communication with the secondary air inlet, wherein the secondary air plenum is substantially isolated from the primary air plenum; a pulse detonation combustor comprising a pulse detonation chamber, wherein the pulse detonation chamber is located downstream of and in fluid communication with the primary air plenum; a coaxial liner surrounding the pulse detonation combustor defining a cooling plenum, wherein the cooling plenum is in fluid communication with the secondary air plenum; an axial turbine assembly located downstream of and in fluid communication with the pulse detonation combustor and the cooling plenum; and a housing encasing the primary air plenum, the secondary air plenum, the pulse detonation combustor, the coaxial liner, and the axial turbine assembly.

  11. Far Field Modeling Methods For Characterizing Surface Detonations

    SciTech Connect

    Garrett, A.

    2015-10-08

    Savannah River National Laboratory (SRNL) analyzed particle samples collected during experiments that were designed to replicate tests of nuclear weapons components that involve detonation of high explosives (HE). SRNL collected the particle samples in the HE debris cloud using innovative rocket propelled samplers. SRNL used scanning electronic microscopy to determine the elemental constituents of the particles and their size distributions. Depleted uranium composed about 7% of the particle contents. SRNL used the particle size distributions and elemental composition to perform transport calculations that indicate in many terrains and atmospheric conditions the uranium bearing particles will be transported long distances downwind. This research established that HE tests specific to nuclear proliferation should be detectable at long downwind distances by sampling airborne particles created by the test detonations.

  12. The initiation and propagation of helium detonations in white dwarf envelopes

    SciTech Connect

    Shen, Ken J.; Moore, Kevin

    2014-12-10

    Detonations in helium-rich envelopes surrounding white dwarfs have garnered attention as triggers of faint thermonuclear '.Ia' supernovae and double detonation Type Ia supernovae. However, recent studies have found that the minimum size of a hotspot that can lead to a helium detonation is comparable to, or even larger than, the white dwarf's pressure scale height, casting doubt on the successful ignition of helium detonations in these systems. In this paper, we examine the previously neglected effects of C/O pollution and a full nuclear reaction network, and we consider hotspots with spatially constant pressure in addition to constant density hotspots. We find that the inclusion of these effects significantly decreases the minimum hotspot size for helium-rich detonation ignition, making detonations far more plausible during turbulent shell convection or during double white dwarf mergers. The increase in burning rate also decreases the minimum shell mass in which a helium detonation can successfully propagate and alters the composition of the shell's burning products. The ashes of these low-mass shells consist primarily of silicon, calcium, and unburned helium and metals and may explain the high-velocity spectral features observed in most Type Ia supernovae.

  13. Excavation Damaged Zones In Rock Salt Formations

    SciTech Connect

    Jockwer, N.; Wieczorek, K.

    2008-07-01

    Salt formations have long been proposed as potential host rocks for nuclear waste disposal. After the operational phase of a repository the openings, e.g., boreholes, galleries, and chambers, have to be sealed in order to avoid the release of radionuclides into the biosphere. For optimising the sealing techniques knowledge about the excavation damaged zones (EDZ) around these openings is essential. In the frame of a project performed between 2004 and 2007, investigations of the EDZ evolution were performed in the Stassfurt halite of the Asse salt mine in northern Germany. Three test locations were prepared in the floor of an almost 20 year old gallery on the 800-m level of the Asse mine: (1) the drift floor as existing, (2) the new drift floor shortly after removing of a layer of about 1 m thickness of the floor with a continuous miner, (3) the new drift floor 2 years after cutting off the 1-m layer. Subject of investigation were the diffusive and advective gas transport and the advective brine transport very close to the opening. Spreading of the brine was tracked by geo-electric monitoring in order to gain information about permeability anisotropy. Results obtained showed that EDZ cut-off is a useful method to improve sealing effectiveness when constructing technical barriers. (authors)

  14. Monitoring the excavation damaged zone by three-dimensional reconstruction of electrical resistivity

    NASA Astrophysics Data System (ADS)

    Lesparre, Nolwenn; Gibert, Dominique; Nicollin, Florence; Nussbaum, Christophe; Adler, Andy

    2013-11-01

    A damaged zone is formed during the excavation of underground galleries, altering the rock properties. From a perspective of nuclear waste storage in deep geological sites, there is a clear interest to monitor the rock properties in such zones. We constructed electrical resistivity tomograms as a function of time to monitor the damaged area in gallery 04 of the Mont Terri underground rock laboratory (Switzerland). Measurements were performed using electrode rings surrounding the gallery. The experience showed a heterogeneous distribution of damages around the gallery and their fast formation after the excavation. Two main areas were concerned by damage formation, located in regions where the bedding was tangential to the excavated gallery. Such regions represented an extension of about 2 m along the gallery walls and reached a depth of 1.5 m. Main damages were created during the next months following the excavation process. Slight variations were still observed 3 yr after the excavation that may be related to the gallery environmental condition fluctuation. The method applied here demonstrates the interest to monitor the whole region surrounding excavated galleries dedicated to host nuclear wastes.

  15. Non-detonable explosive simulators

    DOEpatents

    Simpson, R.L.; Pruneda, C.O.

    1994-11-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules. 5 figs.

  16. Non-detonable explosive simulators

    DOEpatents

    Simpson, Randall L.; Pruneda, Cesar O.

    1994-01-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules.

  17. Improved detonation modeling with CHEETAH

    SciTech Connect

    Heller, A.

    1997-11-01

    A Livermore software program called CHEETAH, an important, even indispensable tool for energetic materials researchers worldwide, was made more powerful in the summer of 1997 with the release of CHEETAH 2.0, an advanced version that simulates a wider variety of detonations. Derived from more than 40 years of experiments on high explosives at Lawrence Livermore and Los Alamos national laboratories, CHEETAH predicts the results from detonating a mixture of specified reactants. It operates by solving thermodynamic equations to predict detonation products and such properties as temperature, pressure, volume, and total energy released. The code is prized by synthesis chemists and other researchers because it allows them to vary the starting molecules and conditions to optimize the desired performance properties. One of the Laboratory`s most popular computer codes, CHEETAH is used at more than 200 sites worldwide, including ones in England, Canada, Sweden, Switzerland, and France. Most sites are defense-related, although a few users, such as Japanese fireworks researchers, are in the civilian sector.

  18. Detonation interaction with an interface

    NASA Astrophysics Data System (ADS)

    Lieberman, D. H.; Shepherd, J. E.

    2007-09-01

    Detonation interaction with an interface was investigated, where the interface separated a combustible from an oxidizing or inert mixture. The ethylene-oxygen combustible mixture had a fuel-rich composition to promote secondary combustion with the oxidizer in the turbulent mixing zone (TMZ) that resulted from the interaction. Sharp interfaces were created by using a nitro-cellulose membrane to separate the two mixtures. The membrane was mounted on a wood frame and inserted in the experimental test section at a 45° angle to the bulk flow direction. The membrane was destroyed by the detonation wave. The interaction resulted in a transmitted and reflected wave at a node point similar to regular shock refraction. A detonation refraction analysis was carried out to compare with the measured shock angles. It was observed that the measured angle is consistently lower than the predicted value. An uncertainty analysis revealed possible explanations for this systematic variation pointing to factors such as the incident wave curvature and the role of the nitro-cellulose diaphragm. Analysis of the TMZ and Mach stem formed from the reflection of the transmitted shock wave off the solid boundary were carried out and found to justify the size and strength of these features as a function of the test gas composition. The role of secondary combustion in the TMZ was also investigated and found to have a small influence on the wave structure.

  19. Optically triggered fire set/detonator system

    DOEpatents

    Chase, Jay B.; Pincosy, Philip A.; Chato, Donna M.; Kirbie, Hugh; James, Glen F.

    2007-03-20

    The present invention is directed to a system having a plurality of capacitor discharge units (CDUs) that includes electrical bridge type detonators operatively coupled to respective explosives. A pulse charging circuit is adapted to provide a voltage for each respective capacitor in each CDU. Such capacitors are discharged through the electrical bridge type detonators upon receiving an optical signal to detonate respective operatively coupled explosives at substantially the same time.

  20. Detonability of hydrocarbon fuels in air

    NASA Technical Reports Server (NTRS)

    Beeson, H. D.; Mcclenagan, R. D.; Bishop, C. V.; Benz, F. J.; Pitz, W. J.; Westbrook, C. K.; Lee, J. H. S.

    1991-01-01

    Studies were conducted of the detonation of gas-phase mixtures of n-hexane and JP-4, with oxidizers as varied as air and pure oxygen, measuring detonation velocities and cell sizes as a function of stoichiometry and diluent concentration. The induction length of a one-dimensional Zeldovich-von Neumann-Doering detonation was calculated on the basis of a theoretical model that employed the reaction kinetics of the hydrocarbon fuels used. Critical energy and critical tube diameter are compared for a relative measure of the heavy hydrocarbon fuels studied; detonation sensitivity appears to increase slightly with increasing carbon number.

  1. Deflagrations and detonations in thermonuclear supernovae.

    PubMed

    Gamezo, Vadim N; Khokhlov, Alexei M; Oran, Elaine S

    2004-05-28

    We study a type Ia supernova explosion using three-dimensional numerical simulations based on reactive fluid dynamics. We consider a delayed-detonation model that assumes a deflagration-to-detonation transition. In contrast with the pure deflagration model, the delayed-detonation model releases enough energy to account for a healthy explosion, and does not leave carbon, oxygen, and intermediate-mass elements in central parts of a white dwarf. This removes the key disagreement between simulations and observations, and makes a delayed detonation the mostly likely mechanism for type Ia supernovae. PMID:15245271

  2. Two phase detonation studies conducted in 1971

    NASA Technical Reports Server (NTRS)

    Nicholls, J. A.

    1972-01-01

    A report is presented describing the research conducted on five phases: (1) ignition of fuel drops by a shock wave and passage of a shock wave over a burning drop, (2) the energy release pattern of a two-phase detonation with controlled drop sizes, (3) the attenuation of shock and detonation waves passing over an acoustic liner, (4) experimental and theoretical studies of film detonations, and (5) a simplified analytical model of a rotating two-phase detonation wave in a rocket motor.

  3. A summary of hydrogen-air detonation experiments

    SciTech Connect

    Guirao, C.M.; Knystautas, R.; Lee, J.H.

    1989-05-01

    Dynamic detonation parameters are reviewed for hydrogen-air-diluent detonations and deflagration-to-detonation transitions (DDT). These parameters include the characteristic chemical length scale, such as the detonation cell width, associated with the three-dimensional cellular structure of detonation waves, critical transmission conditions of confined detonations into unconfined environments, critical initiation energy for unconfined detonations, detonability limits, and critical conditions for DDT. The detonation cell width, which depends on hydrogen and diluent concentrations, pressure, and temperature, is an important parameter in the prediction of critical geometry-dependent conditions for the transmission of confined detonations into unconfined environments and the critical energies for the direct initiation of unconfined detonations. Detonability limits depend on both initial and boundary conditions and the limit has been defined as the onset of single head spin. Four flame propagation regimes have been identified and the criterion for DDT in a smooth tube is discussed. 108 refs., 28 figs., 5 tabs.

  4. Clamshell excavation of a permeable reactive barrier

    NASA Astrophysics Data System (ADS)

    Molfetta, Antonio Di; Sethi, Rajandrea

    2006-06-01

    Nowadays, permeable reactive barriers (PRB) are one of the most widespread techniques for the remediation of contaminated aquifers. Over the past 10 years, the use of iron-based PRBs has evolved from innovative to accepted standard practice for the treatment of a variety of groundwater contaminants (ITRC in: Permeable reactive barriers: lessons learned/new directions. The Interstate Technology and Regulatory Council, Permeable Reactive Barriers Team 2005). Although, a variety of excavation methods have been developed, backhoe excavators are often used for the construction of PRBs. The aim of this study is to describe the emplacement of a full-scale PRB and the benefits deriving from the use of a crawler crane equipped with a hydraulic grab (also known as clamshell excavator) in the excavation phases. The studied PRB was designed to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in Italy. The continuous reactive barrier was designed to be 120 m long, 13 m deep, and 0.6 m thick. The installation of the barrier was accomplished using a clamshell for the excavation of the trench and a guar-gum slurry to support the walls. The performance of this technique was outstanding and allowed the installation of the PRB in 7 days. The degree of precision of the excavation was very high because of the intrinsic characteristics of this excavation tool and of the use of a concrete curb to guide the hydraulic grab. Moreover, the adopted technique permitted a saving of bioslurry thus minimizing the amount of biocide required.

  5. Detonation diffraction through different geometries

    NASA Astrophysics Data System (ADS)

    Sorin, Rémy; Zitoun, Ratiba; Khasainov, Boris; Desbordes, Daniel

    2009-04-01

    We performed the study of the diffraction of a self-sustained detonation from a cylindrical tube (of inner diameter d) through different geometric configurations in order to characterise the transmission processes and to quantify the transmission criteria to the reception chamber. For the diffraction from a tube to the open space the transmission criteria is expressed by d c = k c · λ (with λ the detonation cell size and k c depending on the mixture and on the operture configuration, classically 13 for alkane mixtures with oxygen). The studied geometries are: (a) a sharp increase of diameter ( D/ d > 1) with and without a central obstacle in the diffracting section, (b) a conical divergent with a central obstacle in the diffracting section and (c) an inversed intermediate one end closed tube insuring a double reflection before a final diffraction between the initiator tube and the reception chamber. The results for case A show that the reinitiation process depends on the ratio d/ λ. For ratios below k c the re-ignition takes place at the receptor tube wall and at a fixed distance from the step, i.e. closely after the diffracted shock reflection shows a Mach stem configuration. For ratios below a limit ratio k lim (which depends on D/ d) the re-ignition distance increases with the decrease of d/λ. For both case A and B the introduction of a central obstacle (of blockage ratio BR = 0.5) at the exit of the initiator tube decreases the critical transmission ratio k c by 50%. The results in configuration C show that the re-ignition process depends both on d/ λ and the geometric conditions. Optimal configuration is found that provides the transmission through the two successive reflections (from d = 26 mm to D ch = 200 mm) at as small d/ λ as 2.2 whatever the intermediate diameter D is. This configuration provides a significant improvement in the detonation transmission conditions.

  6. Phase detonated shock tube (PFST)

    SciTech Connect

    Zerwekh, W.D.; Marsh, S.P.; Tan, Tai-Ho

    1993-07-01

    The simple, cylindrically imploding and axially driven fast shock tube (FST) has been a basic component in the high velocity penetrator (HVP) program. It is a powerful device capable of delivering a directed and very high pressure output that has been successfully employed to drive hypervelocity projectiles. The FST is configured from a hollow, high-explosive (HE) cylinder, a low-density Styrofoam core, and a one-point initiator at one end. A Mach stem is formed in the core as the forward-propagating, HE detonation wave intersects the reflected radial wave. This simple FST has been found to be a powerful pressure multiplier. Up to 1-Mbar output pressure can be obtained from this device. Further increase in the output pressure can be achieved by increasing the HE detonation velocity. The FST has been fine tuned to drive a thin plate to very high velocity under an impulse per unit area of about 1 Mbar{mu}s/cm{sup 2}. A 1.5-mm-thick stainless steel disk has been accelerated intact to 0.8 cm/{mu}s under a loading pressure rate of several Mbar/{mu}s. By making the plate curvature slightly convex at the loading side the authors have successfully accelerated it to almost 1.0 cm/{mu}s. The incorporation of a barrel at the end of the FST has been found to be important as confinement of the propellant gas by the barrel tends to accelerate the projectile to higher velocity. The desire to accelerate the plate above 1.0 cm/{mu}s provided the impetus to develop a more advanced fast shock tube to deliver a much higher output pressure. This report describes the investigation of a relatively simple air-lens phase-detonation system (PFST) with fifty percent higher phase-detonation velocity and a modest 2 Mbar output. Code calculations have shown that this PFST acceleration of a plate to about 1.2 cm/{mu}s can be achieved. The performance of these PFSTs has been evaluated and the details are discussed.

  7. Phase detonated shock tube (PFST)

    SciTech Connect

    Zerwekh, W.D.; Marsh, S.P.; Tan, Tai-Ho.

    1993-01-01

    The simple, cylindrically imploding and axially driven fast shock tube (FST) has been a basic component in the high velocity penetrator (HVP) program. It is a powerful device capable of delivering a directed and very high pressure output that has been successfully employed to drive hypervelocity projectiles. The FST is configured from a hollow, high-explosive (HE) cylinder, a low-density Styrofoam core, and a one-point initiator at one end. A Mach stem is formed in the core as the forward-propagating, HE detonation wave intersects the reflected radial wave. This simple FST has been found to be a powerful pressure multiplier. Up to 1-Mbar output pressure can be obtained from this device. Further increase in the output pressure can be achieved by increasing the HE detonation velocity. The FST has been fine tuned to drive a thin plate to very high velocity under an impulse per unit area of about 1 Mbar[mu]s/cm[sup 2]. A 1.5-mm-thick stainless steel disk has been accelerated intact to 0.8 cm/[mu]s under a loading pressure rate of several Mbar/[mu]s. By making the plate curvature slightly convex at the loading side the authors have successfully accelerated it to almost 1.0 cm/[mu]s. The incorporation of a barrel at the end of the FST has been found to be important as confinement of the propellant gas by the barrel tends to accelerate the projectile to higher velocity. The desire to accelerate the plate above 1.0 cm/[mu]s provided the impetus to develop a more advanced fast shock tube to deliver a much higher output pressure. This report describes the investigation of a relatively simple air-lens phase-detonation system (PFST) with fifty percent higher phase-detonation velocity and a modest 2 Mbar output. Code calculations have shown that this PFST acceleration of a plate to about 1.2 cm/[mu]s can be achieved. The performance of these PFSTs has been evaluated and the details are discussed.

  8. Tritium labeling of detonation nanodiamonds.

    PubMed

    Girard, Hugues A; El-Kharbachi, Abdelouahab; Garcia-Argote, Sébastien; Petit, Tristan; Bergonzo, Philippe; Rousseau, Bernard; Arnault, Jean-Charles

    2014-03-18

    For the first time, the radioactive labeling of detonation nanodiamonds was efficiently achieved using a tritium microwave plasma. According to our measurements, the total radioactivity reaches 9120 ± 120 μCi mg(-1), with 93% of (3)H atoms tightly bonded to the surface and up to 7% embedded into the diamond core. Such (3)H doping will ensure highly stable radiolabeled nanodiamonds, on which surface functionalization is still allowed. This breakthrough opens the way to biodistribution and pharmacokinetics studies of nanodiamonds, while this approach can be scalable to easily treat bulk quantities of nanodiamonds at low cost. PMID:24492594

  9. Reduced Model for Detonation Wave

    NASA Astrophysics Data System (ADS)

    Maillet, Jean-Bernard; Soulard, Laurent; Stoltz, Gabriel

    2007-06-01

    We present a mesoscopic model for reactive waves which extends the model proposed by G. Stoltz (G. Stoltz, Europhys. Lett. 76 (2006) 849). A complex molecule (or a group of molecules) is replaced by a single mesoparticle, evolving according to some Dissipative Particle Dynamics. Chemical reactions can be handled in a mean way by considering an additional variable per particle describing a rate of reaction. The evolution of this rate is governed by the kinetics of a reversible exothermic reaction. Numerical results show that the reactive wave behaves like a detonation wave.

  10. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each...

  11. Evaluation of the oblique detonation wave ramjet

    NASA Technical Reports Server (NTRS)

    Morrison, R. B.

    1978-01-01

    The potential performance of oblique detonation wave ramjets is analyzed in terms of multishock diffusion, oblique detonation waves, and heat release. Results are presented in terms of thrust coefficients and specific impulses for a range of flight Mach numbers of 6 to 16.

  12. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each...

  13. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each...

  14. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each...

  15. Shock Initiation and Detonability of Liquid Nitroethane

    NASA Astrophysics Data System (ADS)

    Yoshinaka, Akio; Zhang, Fan

    2004-07-01

    Shock initiation of detonation in liquid nitroethane (NE) was investigated using a cylindrical donor-attenuator-receptor configuration. While NE is less sensitive than nitromethane (NM) and isopropyl nitrate (IPN), similar behaviour of direct initiation of detonation and SDT were observed at higher shock pressures. The critical shock initiation peak pressure was found to be above 9.2 GPa at 17±6 °C initial temperature. Critical diameter experiments were performed using steel and tungsten tubes of various wall thicknesses. The critical diameter was found to lie between 89 mm with 6.6 mm wall (no detonation) and 97 mm with 8.9 mm wall (detonation) in steel tubes, and between 51 mm and 63 mm in 6.35 mm wall tungsten tubes at 21±5 °C. The steady detonation velocity measured was 5.39 mm/μsec.

  16. Prompt detonation of secondary explosives by laser

    SciTech Connect

    Paisley, D.L.

    1989-01-01

    Secondary high explosives have been promptly detonated by directing a laser beam of various wavelengths from 266 nanometers to 1.06 micron on the surface of the explosives. For this paper ''prompt'' means the excess transit time through an explosive charge is /approximately/250 nanoseconds (or less) less than the accepted full detonation velocity time. Timing between laser pulse, explosive initiation and detonation velocity and function time have been recorded. The laser parameters studied include: wavelength, pulse length, energy and power density, and beam diameter (spot size). Explosives evaluated include: PETN, HNS, HMX, and graphited PETN, HNS, and HMX. Explosive parameters that have been correlated with optical parameters include: density, surface area, critical diameter (spot size), spectral characteristics and enhance absorption. Some explosives have been promptly detonated over the entire range of wavelengths, possibly by two competing initiating mechanisms. Other explosives could not be detonated at any of the wavelengths or power densities tested. 8 refs., 12 figs., 1 tab.

  17. Performance characterization of the NASA standard detonator

    SciTech Connect

    Tarbell, W.W.; Burke, T.L.; Solomon, S.E.

    1995-05-01

    The NASA Standard Detonator (NSD) is employed in support of a number of current applications, including the Space Shuttle. This effort was directed towards providing test results to characterize the output of this device for its use in a safe and arm device. As part of the investigation, flash X-ray was used to provide stop-motion photographs of the flying metal plate that is created by initiation of the detonator. This provided researchers with a better understanding of the shape and character of the high-velocity disk as it propagated across the gap between the detonator and next assembly. The second portion of the study used a velocity interferometer to evaluate the acceleration and velocity histories of the flying plate, providing a quantified assessment of the detonator`s ability to initiate the explosive in the next explosive.

  18. Molecular dynamics simulations of weak detonations.

    PubMed

    Am-Shallem, Morag; Zeiri, Yehuda; Zybin, Sergey V; Kosloff, Ronnie

    2011-12-01

    Detonation of a three-dimensional reactive nonisotropic molecular crystal is modeled using molecular dynamics simulations. The detonation process is initiated by an impulse, followed by the creation of a stable fast reactive shock wave. The terminal shock velocity is independent of the initiation conditions. Further analysis shows supersonic propagation decoupled from the dynamics of the decomposed material left behind the shock front. The dependence of the shock velocity on crystal nonlinear compressibility resembles solitary behavior. These properties categorize the phenomena as a weak detonation. The dependence of the detonation wave on microscopic potential parameters was investigated. An increase in detonation velocity with the reaction exothermicity reaching a saturation value is observed. In all other respects the model crystal exhibits typical properties of a molecular crystal. PMID:22304055

  19. Internal Detonation Velocity Measurements Inside High Explosives

    SciTech Connect

    Benterou, J; Bennett, C V; Cole, G; Hare, D E; May, C; Udd, E

    2009-01-16

    In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation models and detonation models of high explosives, the ability to continuously measure the detonation velocity within an explosive is required. Progress on an embedded velocity diagnostic using a 125 micron diameter optical fiber containing a chirped fiber Bragg grating is reported. As the chirped fiber Bragg grating is consumed by the moving detonation wave, the physical length of the unconsumed Bragg grating is monitored with a fast InGaAs photodiode. Experimental details of the associated equipment and data in the form of continuous detonation velocity records within PBX-9502 are presented. This small diameter fiber sensor has the potential to measure internal detonation velocities on the order of 10 mm/{micro}sec along path lengths tens of millimeters long.

  20. Pulse detonation assembly and hybrid engine

    NASA Technical Reports Server (NTRS)

    Rasheed, Adam (Inventor); Dean, Anthony John (Inventor); Vandervort, Christian Lee (Inventor)

    2010-01-01

    A pulse detonation (PD) assembly includes a number of PD chambers adapted to expel respective detonation product streams and a number of barriers disposed between respective pairs of PD chambers. The barriers define, at least in part, a number of sectors that contain at least one PD chamber. A hybrid engine includes a number of PD chambers and barriers. The hybrid engine further includes a turbine assembly having at least one turbine stage, being in flow communication with the PD chambers and being configured to be at least partially driven by the detonation product streams. A segmented hybrid engine includes a number of PD chambers and segments configured to receive and direct the detonation product streams from respective PD chambers. The segmented hybrid engine further includes a turbine assembly configured to be at least partially driven by the detonation product streams.

  1. Mechanical excavator performance in Yucca Mountain tuffs

    SciTech Connect

    Ozdemir, L.; Hansen, F.D.

    1991-01-01

    A research effort of four phases is in progress at the Colorado School of Mines. The overall program will evaluate the cutability of welded tuff and other lithologies likely to be excavated at Yucca Mountain in the site characterization process. Several mechanical systems are considered with emphasis given to the tunnel boring machine. The research comprises laboratory testing, linear drag bit and disc cutter tests and potentially large-scale laboratory demonstrations to support potential use of a tunnel boring machine in welded tuff. Preliminary estimates of mechanical excavator performance in Yucca Mountain tuff are presented here. As phases of the research project are completed, well quantified estimates will be made of performance of mechanical excavators in the Yucca Mountain tuffs. 3 refs., 2 tabs.

  2. Mechanical excavator performance in Yucca Mountain tuffs

    SciTech Connect

    Ozdemir, L.; Hansen, F.D.

    1991-12-31

    A research effort of four phases is in progress at the Colorado School of Mines. The overall program will evaluate the cutability of welded tuff and other lithologies likely to be excavated at Yucca Mountain in the site characterization process. Several mechanical systems are considered with emphasis given to the tunnel boring machine. The research comprises laboratory testing, linear drag bit and disc cutter tests, and potentially large-scale lab. demonstrations to support potential use of a tunnel boring machine in welded tuff. Preliminary estimates of mechanical excavator performance in Yucca Mountain tuff are presented here. As phases of the research project are completed, well-quantified estimates will be made of performance of mechanical excavators in the Yucca Mountain tuffs.

  3. Detonation wave compression in gas turbines

    NASA Technical Reports Server (NTRS)

    Wortman, A.

    1986-01-01

    A study was made of the concept of augmenting the performance of low pressure ratio gas turbines by detonation wave compression of part of the flow. The concept exploits the constant volume heat release of detonation waves to increase the efficiency of the Brayton cycle. In the models studied, a fraction of the compressor output was channeled into detonation ducts where it was processed by transient transverse detonation waves. Gas dynamic studies determined the maximum cycling frequency of detonation ducts, proved that upstream propagation of pressure pulses represented no problems and determined the variations of detonation duct output with time. Mixing and wave compression were used to recombine the combustor and detonation duct flows and a concept for a spiral collector to further smooth the pressure and temperature pulses was presented as an optional component. The best performance was obtained with a single firing of the ducts so that the flow could be re-established before the next detonation was initiated. At the optimum conditions of maximum frequency of the detonation ducts, the gas turbine efficiency was found to be 45 percent while that of a corresponding pressure ratio 5 conventional gas turbine was only 26%. Comparable improvements in specific fuel consumption data were found for gas turbines operating as jet engines, turbofans, and shaft output machines. Direct use of the detonation duct output for jet propulsion proved unsatisfactory. Careful analysis of the models of the fluid flow phenomena led to the conclusion that even more elaborate calculations would not diminish the uncertainties in the analysis of the system. Feasibility of the concept to work as an engine now requires validation in an engineering laboratory experiment.

  4. Numerical Simulation of Rock Mass Damage Evolution During Deep-Buried Tunnel Excavation by Drill and Blast

    NASA Astrophysics Data System (ADS)

    Yang, Jianhua; Lu, Wenbo; Hu, Yingguo; Chen, Ming; Yan, Peng

    2015-09-01

    Presence of an excavation damage zone (EDZ) around a tunnel perimeter is of significant concern with regard to safety, stability, costs and overall performance of the tunnel. For deep-buried tunnel excavation by drill and blast, it is generally accepted that a combination of effects of stress redistribution and blasting is mainly responsible for development of the EDZ. However, few open literatures can be found to use numerical methods to investigate the behavior of rock damage induced by the combined effects, and it is still far from full understanding how, when and to what degree the blasting affects the behavior of the EDZ during excavation. By implementing a statistical damage evolution law based on stress criterion into the commercial software LS-DYNA through its user-subroutines, this paper presents a 3D numerical simulation of the rock damage evolution of a deep-buried tunnel excavation, with a special emphasis on the combined effects of the stress redistribution of surrounding rock masses and the blasting-induced damage. Influence of repeated blast loadings on the damage extension for practical millisecond delay blasting is investigated in the present analysis. Accompanying explosive detonation and secession of rock fragments from their initial locations, in situ stress in the immediate vicinity of the excavation face is suddenly released. The transient characteristics of the in situ stress release and induced dynamic responses in the surrounding rock masses are also highlighted. From the simulation results, some instructive conclusions are drawn with respect to the rock damage mechanism and evolution during deep-buried tunnel excavation by drill and blast.

  5. Shock and Detonation Physics at Los Alamos National Laboratory

    SciTech Connect

    Robbins, David L; Dattelbaum, Dana M; Sheffield, Steve A

    2012-08-22

    WX-9 serves the Laboratory and the Nation by delivering quality technical results, serving customers that include the Nuclear Weapons Program (DOE/NNSA), the Department of Defense, the Department of Homeland Security and other government agencies. The scientific expertise of the group encompasses equations-of-state, shock compression science, phase transformations, detonation physics including explosives initiation, detonation propagation, and reaction rates, spectroscopic methods and velocimetry, and detonation and equation-of-state theory. We are also internationally-recognized in ultra-fast laser shock methods and associated diagnostics, and are active in the area of ultra-sensitive explosives detection. The facility capital enabling the group to fulfill its missions include a number of laser systems, both for laser-driven shocks, and spectroscopic analysis, high pressure gas-driven guns and powder guns for high velocity plate impact experiments, explosively-driven techniques, static high pressure devices including diamond anvil cells and dilatometers coupled with spectroscopic probes, and machine shops and target fabrication facilities.

  6. Pajarito Plateau archaeological surveys and excavations. II

    SciTech Connect

    Steen, C R

    1982-04-01

    Los Alamos National Laboratory continues its archaeological program of data gathering and salvage excavations. Sites recently added to the archaeological survey are described, as well as the results of five excavations. Among the more interesting and important discoveries are (1) the apparently well-established local use of anhydrous lime, and (2) a late pre-Columbian use of earlier house sites and middens for garden plots. Evidence indicated that the local puebloan population was the result of an expansion of upper Rio Grande peoples, not an influx of migrants.

  7. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-01-09

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant considered for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development experiments and the development of the electric launch system design.

  8. Efficacy of Carisolv-assisted caries excavation.

    PubMed

    Cederlund, A; Lindskog, S; Blomlöf, J

    1999-10-01

    As a possible alternative to conventional techniques for excavating caries chemomechanical methods have been developed. Caridex has so far been the dominating product. However, a new system, Carisolv, was recently introduced. The purpose of the present study was to evaluate the caries-dissolving efficacy of Carisolv in vitro. After excavation with Carisolv all dentin surfaces were caries free. However, 6 of the 10 cavities showed residual caries in the dentinoenamel junction. The dentin and enamel surfaces were covered by smear and debris. Since there may be a risk of leaving caries in the dentinoenamel junction proper case selection appears to be of importance to ensure a successful result. PMID:10709512

  9. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-10-12

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant investigated for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development and the development of the electric launch system design.

  10. Initiation of Gaseous Detonation by Conical Projectiles

    NASA Astrophysics Data System (ADS)

    Verreault, Jimmy

    Initiation and stabilization of detonation by hypersonic conical projectiles launched into combustible gas mixtures is investigated. This phenomenon must be understood for the design and optimization of specific hypersonic propulsion devices, such as the oblique detonation wave engine and the ram accelerator. The criteria for detonation initiation by a projectile is also related to fundamental aspects of detonation research, such as the requirement for direct initiation of a detonation by a blast wave. Experimental results of this problem also offer useful references for validation of numerical and theoretical modeling. Projectiles with cone half angles varying from 15° to 60° were launched into stoichiometric mixtures of hydrogen/oxygen with 70% argon dilution at initial pressures between 10 and 200 kPa. The projectiles were launched from a combustion-driven gas gun at velocities up to 2.2 km/s (corresponding to 133% of the Chapman Jouguet velocity). Pictures of the flowfields generated by the projectiles were taken via Schlieren photography. Five combustion regimes were observed about the projectile ranging from prompt and delayed oblique detonation wave formation, combustion instabilities, a wave splitting, and an inert shock wave. Two types of transition from the prompt oblique detonation wave regime to the inert shock regime were observed. The first (the delayed oblique detonation wave regime) showed an inert shock attached to the tip of the projectile followed by a sharp kink at the onset of an oblique detonation wave; this regime occurred by decreasing the cone angle at high mixture pressures. The second (the combustion instabilities regime) exhibited large density gradients due to combustion ignition and quenching phenomena; this regime occurred by decreasing the mixture pressure at large cone angles. A number of theoretical models were considered to predict critical conditions for the initiation of oblique detonations. The Lee-Vasiljev model agreed

  11. Autoignitions and detonations in engines and ducts.

    PubMed

    Bradley, Derek

    2012-02-13

    The origins of autoignition at hot spots are analysed and the pressure pulses that arise from them are related to knock in gasoline engines and to developing detonations in ducts. In controlled autoignition engines, autoignition is benign with little knock. There are several modes of autoignition and the existence of an operational peninsula, within which detonations can develop at a hot spot, helps to explain the performance of various engines. Earlier studies by Urtiew and Oppenheim of the development of autoignitions and detonations ahead of a deflagration in ducts are interpreted further, using a simple one-dimensional theory of the generation of shock waves ahead of a turbulent flame. The theory is able to indicate entry into the domain of autoignition in an 'explosion in the explosion'. Importantly, it shows the influence of the turbulent burning velocity, and particularly its maximum attainable value, upon autoignition. This value is governed by localized flame extinctions for both turbulent and laminar flames. The theory cannot show any details of the transition to a detonation, but regimes of eventually stable or unstable detonations can be identified on the operational peninsula. Both regimes exhibit transverse waves, triple points and a cellular structure. In the case of unstable detonations, transverse waves are essential to the continuing propagation. For hazard assessment, more needs to be known about the survival, or otherwise, of detonations that emerge from a duct into the same mixture at atmospheric pressure. PMID:22213665

  12. Explosion and detonation characteristics of dimethyl ether.

    PubMed

    Mogi, Toshio; Horiguchi, Sadashige

    2009-05-15

    In this study, the explosion and detonation characteristics of dimethyl ether (DME) were experimentally investigated. A spherical pressure vessel with an internal volume of 180L was used as the explosion vessel. Therefore, tubes 10m in length with internal diameters of 25mm and 50mm were used as detonation tubes. In addition, we compared the characteristics of DME with those of propane since DME is considered as a substitute fuel for liquid petroleum gas (LPG). At room temperature and atmospheric pressure, the maximum explosive pressure increased tenfold. The explosion index (K(G) values), an indicator of the intensity of an explosion, was larger than that of propane, indicating that the explosion was intense. No experimental study has been conducted on the detonation behavior of DME so far, but this research confirmed a transition to detonation. The detonation characteristics were similar to the characteristics of the Chapman-Jouguet detonation, and the concentration range for detonation was from 5.5% to 9.0%. PMID:18774641

  13. Effect of Detonation through a Turbine Stage

    NASA Technical Reports Server (NTRS)

    Ellis, Matthew T.

    2004-01-01

    Pulse detonation engines (PDE) have been investigated as a more efficient means of propulsion due to its constant volume combustion rather than the more often used constant pressure combustion of other propulsion systems. It has been proposed that a hybrid PDE-gas turbine engine would be a feasible means of improving the efficiency of the typical constant pressure combustion gas turbine cycle. In this proposed system, multiple pulse detonation tubes would replace the conventional combustor. Also, some of the compressor stages may be removed due to the pressure rise gained across the detonation wave. The benefits of higher thermal efficiency and reduced compressor size may come at a cost. The first question that arises is the unsteadiness in the flow created by the pulse detonation tubes. A constant pressure combustor has the advantage of supplying a steady and large mass flow rate. The use of the pulse detonation tubes will create an unsteady mass flow which will have currently unknown effects on the turbine located downstream of the combustor. Using multiple pulse detonation tubes will hopefully improve the unsteadiness. The interaction between the turbine and the shock waves exiting the tubes will also have an unknown effect. Noise levels are also a concern with this hybrid system. These unknown effects are being investigated using TURBO, an unsteady turbomachinery flow simulation code developed at Mississippi State University. A baseline case corresponding to a system using a constant pressure combustor with the same mass flow rate achieved with the pulse detonation hybrid system will be investigated first.

  14. Investigation of detonation initiation in aluminium suspensions

    NASA Astrophysics Data System (ADS)

    Veyssiere, B.; Khasainov, B. A.; Briand, A.

    2008-09-01

    Detonation initiation is investigated in aluminium/oxygen and aluminium/air mixtures. Critical conditions for initiation of spherical detonations are examined in analogy with the criteria defined for gaseous mixtures, which correlate critical parameters of detonation initiation to the characteristic size of the cellular structure. However, experimental data on the detonation cell size in these two-phase mixtures are very scarce, on account of the difficulty to perform large-scale experiments. Therefore, 2D numerical simulations of the detonation cellular structure have been undertaken, with the same combustion model for Al/air and Al/O2 mixtures. The cell size is found to be λ = 37.5 cm for a rich ( r = 1.61) aluminium-air mixture, and λ = 7.5 cm for a stoichiometric aluminium-oxygen mixture, which is in reasonable agreement with available experimental data. Calculations performed in large-scale configurations (up to 25 m in length and 1.5 m in lateral direction) suggest that the critical initiation energy and predetonation radius for direct initiation of the unconfined detonation in the aluminium-air mixture are, respectively, 10 kg of TNT and 8 m. Moreover, numerical simulations reveal that the structure of the detonation wave behind the leading front is even more complicated than in pure gaseous mixtures, due to two-phase flow effects.

  15. On the Existence of Pathological Detonation Waves

    SciTech Connect

    Tarver, C M

    2003-07-11

    Pathological detonation waves with velocities greater than Chapman-Jouguet (C-J) have been proposed theoretically but never observed experimentally in gaseous, liquid or solid explosives. Two types of pathological chemical reaction zones have been identified within the Zeldovich-von Neumann-Doring (ZND) model: an exothermic chemical decomposition with a mole decrease during from the von Neumann spike state to the C-J state and an exothermic reaction followed by an endothermic reaction (eigenvalue detonation). The high temperatures reached in detonation reaction zones cause sufficient radial and atom formation to insure overall mole increases in gaseous H{sub 2} + O{sub 2} detonations. Aluminized explosives exhibit a slight mole decrease when the solid aluminum particles are oxidized, but this does not negate the large mole increase that occurs during explosive decomposition. Porous solid explosives whose products form with more cold compression energy than that of the solid are an unlikely possibility for pathological detonation. Eigenvalue detonations have been postulated for H{sub 2} + Cl{sub 2} gas phase detonations and for plastic bonded solid explosives if endothermic binder decomposition follows exothermic explosive decomposition. Chemical kinetic and physical arguments are presented to eliminate these possible pathological detonations. In the case of H{sub 2} + Cl{sub 2}, highly vibrationally excited HCl molecules dissociate Cl{sub 2} molecules during the exothermic portion of the reaction zone rather than later in the flow process. In the plastic bonded explosives, the binders are located on the surfaces of explosive particles and thus are exposed to ''hot spots'' created by the three-dimensional Mach stem shock front. Any remaining binder material rapidly reacts in collisions with the high, vibrationally excited reaction products formed during explosive decomposition. Therefore eigenvalue detonations are extremely unlikely to occur in gaseous, liquid or

  16. 100 area excavation treatability test plan

    SciTech Connect

    Not Available

    1993-05-01

    This test plan documents the requirements for a treatability study on field radionuclide analysis and dust control techniques. These systems will be used during remedial actions involving excavation. The data from this treatability study will be used to support the feasibility study (FS) process. Development and screening of remedial alternatives for the 100 Area, using existing data, have been completed and are documented in the 100 Area Feasibility Study, Phases 1 and 2 (DOE-RL 1992a). Based on the results of the FS, the Treatability Study Program Plan (DOE-RL 1992b) identifies and prioritizes treatability studies for the 100 Area. The data from the treatability study program support future focused FS, interim remedial measures (IRM) selection, operable unit final remedy selection, remedial design, and remedial actions. Excavation is one of the high-priority, near-term, treatability study needs identified in the program plan (DOE-RL 1992b). Excavation of contaminated soils and buried solid wastes is included in several of the alternatives identified in the 100 Area FS. Although a common activity, excavation has only been used occasionally at the Hanford Site for waste removal applications.

  17. Compact Hydraulic Excavator and Support Unit

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1985-01-01

    Continuous-coal-mining machine maneuverable. Hydraulic coal excavator combined with chock, or roof-support structure, in self-contained unit that moves itself forward as it removes coal from seam. Unlike previous such units, new machine compact enough to be easily maneuverable; even makes small-radius right-angle turns.

  18. Excavated Documents Dealing with Chinese Astronomy

    NASA Astrophysics Data System (ADS)

    Guan, Yuzhen

    The materials ancient Chinese scholars used to write on changed from bamboo strips, wooden tablets, and silk in early China to paper in the later dynasties. This chapter will focus on excavated documents dealing with ancient Chinese astronomy and explore some of the ways that scholars have made use of these archaeological resources.

  19. Excavations in Hanford ponds, cribs, or ditches

    SciTech Connect

    Ryan, G.W., Westinghouse Hanford

    1996-07-30

    This document supports the development and presentation of the following accident scenario in the TWRS Final Safety Analysis Report: Unplanned Excavation/Drilling in Pond/Ditch/Crib. The calculations needed to quantify the risk associated with this accident scenario are included within.

  20. Detonator comprising a nonlinear transmission line

    SciTech Connect

    Elizondo-Decanini, Juan M

    2014-12-30

    Detonators are described herein. In a general embodiment, the detonator includes a nonlinear transmission line that has a variable capacitance. Capacitance of the nonlinear transmission line is a function of voltage on the nonlinear transmission line. The nonlinear transmission line receives a voltage pulse from a voltage source and compresses the voltage pulse to generate a trigger signal. Compressing the voltage pulse includes increasing amplitude of the voltage pulse and decreasing length of the voltage pulse in time. An igniter receives the trigger signal and detonates an explosive responsive to receipt of the trigger signal.

  1. Eigenvalue Detonation of Combined Effects Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Capellos, C.; Baker, E. L.; Nicolich, S.; Balas, W.; Pincay, J.; Stiel, L. I.

    2007-12-01

    Theory and performance for recently developed combined—effects aluminized explosives are presented. Our recently developed combined-effects aluminized explosives (PAX-29C, PAX-30, PAX-42) are capable of achieving excellent metal pushing, as well as high blast energies. Metal pushing capability refers to the early volume expansion work produced during the first few volume expansions associated with cylinder and wall velocities and Gurney energies. Eigenvalue detonation explains the observed detonation states achieved by these combined effects explosives. Cylinder expansion data and thermochemical calculations (JAGUAR and CHEETAH) verify the eigenvalue detonation behavior.

  2. Numerical Simulation of Aluminum Dust Detonations with Different Product Phases

    NASA Astrophysics Data System (ADS)

    Teng, H. H.; Jiang, Z. L.

    Detonation waves are waves of supersonic combustion induced by strong coupling shock and heat release. Detonation research has attracted much attention in recent years owing to its potential applications in hypersonic propulsion. Aluminum (Al) particle detonation is a type of dust detonation, and its research is important in the prevention of industrial explosions. Al dust detonations for flake and spherical particles have been studied , which is found to be very sensitive to the specific area[1].

  3. Printable sensors for explosive detonation

    SciTech Connect

    Griffith, Matthew J. Cooling, Nathan A.; Elkington, Daniel C.; Belcher, Warwick J.; Dastoor, Paul C.; Muller, Elmar

    2014-10-06

    Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently amplified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.

  4. Three-dimensional Simulations of Thermonuclear Detonation with α-Network: Numerical Method and Preliminary Results

    NASA Astrophysics Data System (ADS)

    Khokhlov, A.; Domínguez, I.; Bacon, C.; Clifford, B.; Baron, E.; Hoeflich, P.; Krisciunas, K.; Suntzeff, N.; Wang, L.

    2012-07-01

    We describe a new astrophysical version of a cell-based adaptive mesh refinement code ALLA for reactive flow fluid dynamic simulations, including a new implementation of α-network nuclear kinetics, and present preliminary results of first three-dimensional simulations of incomplete carbon-oxygen detonation in Type Ia Supernovae.

  5. 4. VIEW SHOWING EXCAVATION IN ARIZONA CANAL, 8 MILES NORTHEAST ...

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

    4. VIEW SHOWING EXCAVATION IN ARIZONA CANAL, 8 MILES NORTHEAST OF PHOENIX. NOTE MEN DRILLING AND EXCAVATING IN OPERATION; CAMELBACK MOUNTAIN IN THE DISTANCE Photographer: Walter J. Lubken. No date - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ

  6. Propagation of detonations in hydrazine vapor

    NASA Technical Reports Server (NTRS)

    Heinrich, H. J.

    1985-01-01

    In the range of greater hydrazine vapor pressure, detonation speed depends exclusively on the extent of the ammonia decomposition in the second reaction stage. As vapor pressure decreases, the ammonia disintegration speed becomes increasingly slower and the reaction reached in the reaction zone increasingly decreases until finally, in the vapor pressure range between 53 and 16 Torr, the contribution of the second stage to detonation propagation disappears, and only the first stage remains active. Since the disintegration speed of the hydrazine in this pressure range has decreased markedly as well, no level, but rather only spinning, detonations occur. Temporary separations of the impact front and the reaction zone in the process lead to fluctuations of the detonation speed.

  7. Detonation wave augmentation of gas turbines

    NASA Technical Reports Server (NTRS)

    Wortman, A.

    1984-01-01

    The results of a feasibility study that examined the effects of using detonation waves to augment the performance of gas turbines are reported. The central ideas were to reduce compressor requirements and to maintain high performance in jet engines. Gasdynamic equations were used to model the flows associated with shock waves generated by the detonation of fuel in detonator tubes. Shock wave attenuation to the level of Mach waves was found possible, thus eliminating interference with the compressor and the necessity of valves and seals. A preliminary parametric study of the performance of a compressor working at a 4:1 ratio in a conceptual design of a detonation wave augmented jet engine in subsonic flight indicated a clear superiority over conventional designs in terms of fuel efficiency and thrust.

  8. Parametric study of double cellular detonation structure

    NASA Astrophysics Data System (ADS)

    Khasainov, B.; Virot, F.; Presles, H.-N.; Desbordes, D.

    2013-05-01

    A parametric numerical study is performed of a detonation cellular structure in a model gaseous explosive mixture whose decomposition occurs in two successive exothermic reaction steps with markedly different characteristic times. Kinetic and energetic parameters of both reactions are varied in a wide range in the case of one-dimensional steady and two-dimensional (2D) quasi-steady self-supported detonations. The range of governing parameters of both exothermic steps is defined where a "marked" double cellular structure exists. It is shown that the two-level cellular structure is completely governed by the kinetic parameters and the local overdrive ratio of the detonation front propagating inside large cells. Furthermore, since it is quite cumbersome to use detailed chemical kinetics in unsteady 2D case, the proposed work should help to identify the mixtures and the domain of their equivalence ratio where double detonation structure could be observed.

  9. 29 CFR 1926.651 - Specific excavation requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Specific excavation requirements. 1926.651 Section 1926.651 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Excavations § 1926.651 Specific excavation requirements. (a)...

  10. Acoustic emission and ultrasonic-velocity methods used to characterise the excavation disturbance associated with deep tunnels in hard rock

    NASA Astrophysics Data System (ADS)

    Falls, Stephen D.; Young, R. Paul

    1998-04-01

    Acoustic emission (AE) and ultrasonic-velocity monitoring studies have been undertaken at both the Atomic Energy of Canada Limited (AECL) Underground Research Laboratory (URL) and at the Swedish Nuclear Fuel Waste Management Company (SKB) Hard Rock Laboratory (HRL). At both locations the excavations were tunnels in granitic material at approximately 420 m depth. However, the stress regime was more severe at the URL Mine-by tunnel site than the HRL ZEDEX tunnel. Different parts of the ZEDEX tunnel were created using different excavation techniques. Using AE and ultrasonic techniques to study these tunnels we have been able to examine the nature of the excavation-disturbed zone around the tunnel, as well as examining the effects of different stress regimes and excavation techniques. Studies were undertaken both during and after the Mine-by tunnel excavation and during excavation in the ZEDEX tunnel. AE monitoring in the wall of the Mine-by tunnel during excavation showed that some activity occurred in the sidewall regions, but the spatial density of AE hypocentres increased toward the regions in the floor and roof of the tunnel where breakout notches formed. This sidewall activity was clustered primarily within 0.5 m of the tunnel wall. AE monitoring in the floor of the tunnel showed that small numbers of AE continued to occur in the notch region in the floor of the tunnel over 2 years after excavation was completed. This activity became more acute as the rock was heated, imposing thermally induced stresses on the volume. Ultrasonic-velocity studies both in the floor and the wall of the tunnel showed that the velocity is strongly anisotropic with the direction of slowest velocity orthogonal to the tunnel surface. The velocity increased with distance into the rock from the tunnel surface. In the floor, this effect was seen up to 2 m from the tunnel surface. Most of the change occurred within the first 0.5 m from the tunnel perimeter. At the lower-stress HRL, most of

  11. Deflagration to detonation transition in thermonuclear supernovae

    SciTech Connect

    Khokhlov, A.M.; Oran, E.S.; Wheeler, J.C.

    1996-12-03

    The authors derive the criteria for deflagration to detonation transition (DDT) in a Type Ia supernova. The theory is based on the two major assumptions: (i) detonation is triggered via the Zeldovich gradient mechanism inside a region of mixed fuel and products, (ii) the mixed region is produced by a turbulent mixing of fuel and products either inside an active deflagration front or during the global expansion and subsequent contraction of an exploding white dwarf. The authors determine the critical size of the mixed region required to initiate a detonation in a degenerate carbon oxygen mixture. This critical length is much larger than the width of the reaction front of a Chapman-Jouguet detonation. However, at densities greater than = 5 x 10{sup 6} g/cc, it is much smaller than the size of a white dwarf. They derive the critical turbulent intensity required to create the mixed region inside an active deflagration front in which a detonation can form. They conclude that the density rho sub sigma at which a detonation can form in a carbon-oxygen white dwarf is low, approximately less than 2 to 5 x 10{sup 6} g/cc, but greater than 5 x 10{sup 6} g/cc.

  12. Prechamber initiation of detonation in gaseous mixtures

    NASA Astrophysics Data System (ADS)

    Bivol, G. Yu; Golovastov, S. V.; Golub, V. V.

    2015-11-01

    A process of deflagration-to-detonation transition in propane-butane-oxygen and acetylene-oxygen mixtures, in an open channel with a circular cross section with a diameter of 3 mm, was investigated experimentally. Detonation initiation was carried out by burning the mixture in the prechamber connected to the channel. The prechamber was considered as an extended source for the initiation of the detonation of a finite volume. To measure the velocity of a flame front, photodiodes, installed along the axis of the channel, were used. To determine the boundary conditions at the entrance to the channel, a piezoelectric pressure transducer was used. The influence of the dimensions of the prechamber, equivalence ratio and fuel on the pressure profile, and evolution of the flame front along the axis of the channel are presented. It was shown that, the dynamics of the flame front and shock waves in the channel can occur in different scenarios depending on the geometry of the prechamber and equivalence ratio. Two limit effects of the prechamber detonation initiation in the channel have been analyzed. The pre-detonation distances and the minimal energy of direct initiation of the detonation were determined.

  13. Effect of Resolution on Propagating Detonation Wave

    SciTech Connect

    Menikoff, Ralph

    2014-07-10

    Simulations of the cylinder test are used to illustrate the effect of mesh resolution on a propagating detonation wave. For this study we use the xRage code with the SURF burn model for PBX 9501. The adaptive mesh capability of xRage is used to vary the resolution of the reaction zone. We focus on two key properties: the detonation speed and the cylinder wall velocity. The latter is related to the release isentrope behind the detonation wave. As the reaction zone is refined (2 to 15 cells for cell size of 62 to 8μm), both the detonation speed and final wall velocity change by a small amount; less than 1 per cent. The detonation speed decreases with coarser resolution. Even when the reaction zone is grossly under-resolved (cell size twice the reaction-zone width of the burn model) the wall velocity is within a per cent and the detonation speed is low by only 2 per cent.

  14. Initiation and Detonation Physics on Millimeter Scales

    SciTech Connect

    Philllips, D F; Benterou, J J; May, C A

    2012-03-20

    The LLNL Detonation Science Project has a major interest in understanding the physics of detonation on a millimeter scale. This report summarizes the rate stick experiment results of two high explosives. The GO/NO-GO threshold between varying diameters of ultra-fine TATB (ufTATB) and LX-16 were recorded on an electronic streak camera and analyzed. This report summarizes the failure diameters of rate sticks for ufTATB and LX-16. Failure diameter for the ufTATB explosive, with densities at 1.80 g/cc, begin at 2.34 mm (not maintaining detonation velocity over the entire length of the rate stick). ufTATB rate sticks at the larger 3.18 mm diameter maintain a constant detonation velocity over the complete length. The PETN based and LLNL developed explosive, LX-16, with densities at 1.7 g/cc, shows detonation failure between 0.318 mm and 0.365 mm. Additional tests would be required to narrow this failure diameter further. Many of the tested rate sticks were machined using a femtosecond laser focused into a firing tank - in case of accidental detonation.

  15. The propagation mechanism of cellular detonation

    NASA Astrophysics Data System (ADS)

    Lee, J. H. S.

    The present lecture examined the available experimental and numerical results on cellular detonations. It is concluded that apart from special mixtures where the detonation is only "weakly unstable", the classical shock ignition and thermal explosion mechanism cannot describe the physical and chemical processes in the highly complex reaction zone of unstable detonations in general. Turbulence will play an important role in both the ignition and the combustion mechanism in the reaction zone of highly unstable detonations. Vorticity and turbulence generation from shock-shock, shock-vortex, shock-density interactions and the baroclinic torque mechanism are considered important in contrast to the velocity gradient shear flow mechanism of turbulence production in incompressible flows. It is recommended that the experimental determination of the hydrodynamic thickness, its correlation with chemical, thermodynamic and transport properties of the mixture and the formulation of a turbulence model to describe the steady mean flow properties of cellular detonation structure are important problems in detonation research for the immediate future.

  16. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2003-06-06

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant considered for similar concepts in the past. This document reports on the program findings through the first two phases. It presents projectile design and experiment data and the preliminary design for electric launch system. Advanced Power Technologies, Inc., now BAE SYSTEMS Advanced Technologies, Inc., was forced to withdraw from the program with the loss of one of our principal mining partners, however, the experiments conducted suggest that the approach is feasible and can be made cost effective.

  17. 118-B-1 excavation treatability test plan

    SciTech Connect

    Not Available

    1994-07-01

    The Hanford 118-B-1 Burial Ground Treatability Study has been required by milestone change request {number_sign}M-15-93-04, dated September 30, 1993. The change request requires that a treatability test be conducted at the 100-B Area to obtain additional engineering information for remedial design of burial grounds receiving waste from 100 Area removal actions. This treatability study has two purposes: (1) to support development of the Proposed Plan (PP) and Record of Decision (ROD), which will identify the approach to be used for burial ground remediation, and (2) to provide specific engineering information for receiving waste generated from the 100 Area removal actions. Data generated from this test also will provide critical performance and cost information necessary for remedy evaluation in the detailed analysis of alternatives during preparation of the focused feasibility study (FFS). This treatability testing supports the following 100 Area alternatives: (1) excavation and disposal, and (2) excavation, sorting, (treatment), and disposal.

  18. Near-Failure Detonation Behavior of Vapor-Deposited Hexanitrostilbene (HNS) Films

    NASA Astrophysics Data System (ADS)

    Knepper, Robert; Wixom, Ryan; Tappan, Alexander

    2015-06-01

    Physical vapor deposition is an attractive method to produce sub-millimeter explosive samples for studying detonation behavior at near-failure conditions. In this work, we examine hexanitrostilbene (HNS) films deposited onto polycarbonate substrates using vacuum thermal sublimation. Deposition conditions are varied in order to alter porosity in the films, and the resulting microstructures are quantified by analyzing ion-polished cross-sections using scanning electron microscopy. The effects of these changes in microstructure on detonation velocity and the critical thickness needed to sustain detonation are determined. The polycarbonate substrates can act as recording plates for detonation experiments, and films near the critical thickness display distinct patterns in the dent tracks that indicate instabilities in the detonation front when approaching failure conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. Three-dimensional Delayed-Detonation Model of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Gamezo, Vadim N.; Khokhlov, Alexei M.; Oran, Elaine S.

    2005-04-01

    We study a Type Ia supernova explosion using large-scale three-dimensional numerical simulations based on reactive fluid dynamics with a simplified mechanism for nuclear reactions and energy release. The initial deflagration stage of the explosion involves a subsonic turbulent thermonuclear flame propagating in the gravitational field of an expanding white dwarf. The deflagration produces an inhomogeneous mixture of unburned carbon and oxygen with intermediate-mass and iron-group elements in central parts of the star. During the subsequent detonation stage, a supersonic detonation wave propagates through the material unburned by the deflagration. The total energy released in this delayed-detonation process, (1.3-1.6)×1051 ergs, is consistent with a typical range of kinetic energies obtained from observations. In contrast to the deflagration model, which releases only about 0.6×1051 ergs, the delayed-detonation model does not leave carbon, oxygen, and intermediate-mass elements in central parts of a white dwarf. This removes the key disagreement between three-dimensional simulations and observations, and makes a delayed detonation the mostly likely mechanism for Type Ia supernova explosions.

  20. CLASSIFICATION OF THE MGR SUBSURFACE EXCAVATION SYSTEM

    SciTech Connect

    R. Garrett

    1999-08-31

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) subsurface excavation system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).

  1. Lunar Regolith Excavation Student Competition Design

    NASA Technical Reports Server (NTRS)

    Nething, Julia

    2009-01-01

    The Surface Systems team is working to learn about lunar regolith and how we can use it as a source of air, water, and fuel for spacecrafts. However, excavation of this valuable regolith is difficult because the robot has to conform to many specifications (mass limit, efficiency level, etc.). NASA has therefore decided to include college students and companies in the search to create the best robot by making it into a competition.

  2. Telerobotic excavation system for unexploded ordnance retrieval

    SciTech Connect

    Burks, B.L.; Killough, S.M.; Thompson, D.H.; Rossi, R.A.

    1994-12-31

    The small emplacement excavator (SEE) is a ruggedized military vehicle with backhoe and front loader used by the US Army for unexploded ordnance (UXO) retrieval and general utility excavation activities. In order to evaluate the feasibility of removing personnel from the vehicle during high-risk excavation tasks a development and demonstration project was initiated to evaluate performance capabilities of the SEE under telerobotic control. A technology demonstration of the TSEE was conducted at McKinley Range, Redstone Arsenal, Huntsville, Alabama on 13--17 September, 1993. The primary objective of the demonstration was to evaluate and demonstrate the feasibility of remote UXO retrieval. During the demonstration, explosive ordnance disposal specialists were instructed on telerobotic operation of the TSEE, and then were asked to complete a simulated UXO retrieval task. Participants then submitted an evaluation of the system including human factors performance data. This presentation will describe the TSEE, retrieval demonstration, and summarize results of the performance evaluations. Some examples of the results are given below. Seventy percent of the demonstration participants found the tasks were as easy or easier to accomplish utilizing the remote system than with an unmodified system. Similarly, eighty percent of the participants found the TSEE hand controller was as easy or easier to use than the normal manual controls.

  3. National Advanced Drilling and Excavation Technologies Program

    SciTech Connect

    1993-06-15

    The second meeting of Federal agency representatives interested in the National Advanced Drilling and Excavation Technologies (NADET) Program took place on June 15, 1993. The Geothermal Division of the U.S. Department of Energy (DOE) hosted the meeting at the Washington, D.C., offices of DOE. Representatives from the National Science Foundation, U.S. Geological Survey, U.S. Bureau of Mines, National Institute of Standards and Technology, National Aeronautics and Space Administration, Environmental Protection Agency, and various offices within the Department of Energy attended. For a complete list of attendees see Attachment A. The purpose of the meeting was: (1) to cover the status of efforts to gain formal approval for NADET, (2) to brief participants on events since the last meeting, especially two recent workshops that explored research needs in drilling and excavation, (3) to review some recent technological advances, and (4) to solicit statements of the importance of improving drilling and excavation technologies to the missions of the various agencies. The meeting agenda is included as Attachment B.

  4. Discrete Element Modeling for Mobility and Excavation

    NASA Astrophysics Data System (ADS)

    Knuth, M. A.; Hopkins, M. A.

    2011-12-01

    The planning and completion of mobility and excavation efforts on the moon requires a thorough understanding of the planetary regolith. In this work, a discrete element method (DEM) model is created to replicate those activities in the laboratory and for planning mission activities in the future. The crux of this work is developing a particle bed that best replicates the regolith tool/wheel interaction seen in the laboratory. To do this, a DEM geotechnical triaxial strength cell was created allowing for comparison of laboratory JSC-1a triaxial tests to DEM simulated soils. This model relies on a triangular lattice membrane covered triaxial cell for determining the macroscopic properties of the modeled granular material as well as a fast and efficient contact detection algorithm for a variety of grain shapes. Multiple grain shapes with increasing complexity (ellipsoid, poly-ellipsoid and polyhedra) have been developed and tested. This comparison gives us a basis to begin scaling DEM grain size and shape to practical values for mobility and excavation modeling. Next steps include development of a DEM scoop for percussive excavation testing as well as continued analysis of rover wheel interactions using a wide assortment of grain shape and size distributions.

  5. One Year Term Review as a Participating Guest in the Detonator and Detonation Physics Group

    SciTech Connect

    Lefrancois, A; Roeske, F; Tran, T; Lee, R S

    2006-02-06

    The one year stay was possible after a long administrative process, because of the fact that this was the first participating guest of B division as a foreign national in HEAF (High Explosives Application Facility) with the Detonator/Detonation Physics Group.

  6. Detonability of H/sub 2/-air-diluent mixtures

    SciTech Connect

    Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.; Berman, M.

    1987-06-01

    This report describes the Heated Detonation Tube (HDT). Detonation cell width and velocity results are presented for H/sub 2/-air mixtures, undiluted and diluted with CO/sub 2/ and H/sub 2/O for a range of H/sub 2/ concentration, initial temperature and pressure. The results show that the addition of either CO/sub 2/ or H/sub 2/O significantly increases the detonation cell width and hence reduces the detonability of the mixture. The results also show that the detonation cell width is reduced (detonability is increased) for increased initial temperature and/or pressure.

  7. Deflagration to detonation transition in combustible gas mixtures

    SciTech Connect

    Smirnov, N.N.; Panfilov, I.I.

    1995-04-01

    This paper presents the results of a computational investigation of the process of deflagration to detonation transition in a combustible gas mixture. The type of combustion (i.e., deflagration or detonation) supported by a two-step reaction scheme is studied as a function of the activation energies. It is shown that both a deflagration to detonation transition and a deflagration wave that lags behind a leading shock are possible. Two types of deflagration to detonation transitions are found theoretically: initiation of detonation from the flame zone and initiation of detonation along a contact discontinuity in the compressed gas near the primary shock wave.

  8. Gaseous detonation synthesis and characterization of nano-oxide

    NASA Astrophysics Data System (ADS)

    Yan, Honghao; Wu, Linsong; Li, Xiaojie; Wang, Xiaohong

    2015-07-01

    Gaseous detonation is a new method of heating the precursor of nanomaterials into gas, and integrating it with combustible gas as mixture to be detonated for the synthesis of nanomaterials. In this paper, the mixed gas of oxygen and hydrogen is used as the source for detonation, to synthesize nano TiO2, nano SiO2 and nano SnO2 through gaseous detonation method, characterization and analysis of the products, it was found that the products from gaseous detonation method were of high purity, good dispersion, smaller particle size and even distribution. It also shows that for the synthesis of nano-oxides, gaseous detonation is universal.

  9. High order hybrid numerical simulations of two dimensional detonation waves

    NASA Technical Reports Server (NTRS)

    Cai, Wei

    1993-01-01

    In order to study multi-dimensional unstable detonation waves, a high order numerical scheme suitable for calculating the detailed transverse wave structures of multidimensional detonation waves was developed. The numerical algorithm uses a multi-domain approach so different numerical techniques can be applied for different components of detonation waves. The detonation waves are assumed to undergo an irreversible, unimolecular reaction A yields B. Several cases of unstable two dimensional detonation waves are simulated and detailed transverse wave interactions are documented. The numerical results show the importance of resolving the detonation front without excessive numerical viscosity in order to obtain the correct cellular patterns.

  10. Excavation of Regolith by Impinging Jets of Gas

    NASA Technical Reports Server (NTRS)

    Metzger, Philip T.; Immer, Christopher D.; Vu, Bruce T.; Donahue, Carly M.

    2006-01-01

    There are many situations in nature and technology where particulate matter is excavated by a fluid jet. Such a process is often used to excavate soil or to dig wells. Air jets are often used to transport particulate matter such as powders in various industrial processes. Similar situations occur in nature, as when waterfalls scour holes in sand. In other cases, the excavation is unwanted such as when a rocket lands on the sandy or dusty surface of a planet or moon. Recent research into regolith excavation by gas jets has obtained new insights into the physical processes of that excavation, and these may lead to new advances in technology for more efficient fluid-jet excavation processes and for better control of the unwanted excavation effects of landing rockets. This talk will explain the new insights and point to future work supporting lunar exploration.

  11. Production Pathways and Separation Procedures for High-Diagnostic-Value Activation Species, Fission Products, and Actinides Required for Preparation of Realistic Synthetic Post-Detonation Nuclear Debris: Status Report and FY16 Project Plan

    SciTech Connect

    Faye, S. A.; Shaughnessy, D. A.

    2015-08-19

    The objective of this project is to provide a comprehensive study on the production routes and chemical separation requirements for activation products, fission products, and actinides required for the creation of realistic post-detonation surrogate debris. Isotopes that have been prioritized by debris diagnosticians will be examined for their ability to be produced at existing irradiation sources, production rates, and availability of target materials, and chemical separation procedures required to rapidly remove the products from the bulk target matrix for subsequent addition into synthetic debris samples. The characteristics and implications of the irradiation facilities on the isotopes of interest will be addressed in addition to a summary of the isotopes that are already regularly produced. This is a planning document only.

  12. Jet initiation of deflagration and detonation

    NASA Astrophysics Data System (ADS)

    Krok, James Christopher

    We have constructed a facility for the study of jet-initiated deflagration and detonation in hydrogen-air-steam mixtures. The facility is built around two pressure vessels. Mixtures of hydrogen, oxygen and nitrogen are spark-ignited in the driver vessel, generating a hot mixture of combustion products. The pressure rise ruptures a diaphragm, venting the products into the receiver vessel through nozzles of 12.7-92 mm diameter. The receiver is filled with hydrogen-air and hydrogen-oxygen mixtures diluted with either nitrogen or steam. The deflagration tests studied the lean and maximum-dilution limits of hydrogen-air mixtures ignited by a hydrogen-steam jet. The lean limit of 6% hydrogen was comparable to other studies. The maximum dilution limit for steam was 60%. This is higher than the limit found in spark/glow plug ignition experiments. Shock oscillations in the receiver increased with nozzle size. Further tests studied the initiation of detonation in both hydrogen-air and stoichiometric hydrogen-oxygen-diluent mixtures. In terms of jet diameter, D, and receiver detonation cell size, lambda, we found initiation limits of 2detonation. Mixtures with steam dilution were prone to DDT near the detonation limit, as the slower flame speed allows shock reflection and pressurization to occur before the reactants are consumed. Tests with nitrogen dilution had no DDT regime. Because of DDT and shock focusing, peak pressures were highest in mixtures that were slightly less sensitive than the detonation threshold. Schlieren movies confirmed the formation of a detonation near the nozzle exit.

  13. Jet initiation of deflagration and detonation

    NASA Astrophysics Data System (ADS)

    Krok, James Christopher

    We have constructed a facility for the study of jet-initiated deflagration and detonation in hydrogen-air-steam mixtures. The facility is built around two pressure vessels. Mixtures of hydrogen, oxygen and nitrogen are spark-ignited in the driver vessel, generating a hot mixture of combustion products. The pressure rise ruptures a diaphragm, venting the products into the receiver vessel through nozzles of 12.7-92 mm diameter. The receiver is filled with hydrogen-air and hydrogen-oxygen mixtures diluted with either nitrogen or steam.The deflagration tests studied the lean and maximum-dilution limits of hydrogen-air mixtures ignited by a hydrogen-steam jet. The lean limit of 6% hydrogen was comparable to other studies. The maximum dilution limit for steam was 60%. This is higher than the limit found in spark/glow plug ignition experiments. Shock oscillations in the receiver increased with nozzle size.Further tests studied the initiation of detonation in both hydrogen-air and stoichiometric hydrogen-oxygen-diluent mixtures. In terms of jet diameter, D, and receiver detonation cell size, [?], we found initiation limits of 2 < D[?] < 7, where other experiments required a D[?] of 11 or more. We propose that the D[?] model does not adequately characterize jet initiation, as it does not reflect the conditions in the driver.The tests indicated that shock focusing plays an important role, promoting strong secondary explosions with or without prompt initiation of detonation. Mixtures with steam dilution were prone to DDT near the detonation limit, as the slower flame speed allows shock reflection and pressurization to occur before the reactants are consumed. Tests with nitrogen dilution had no DDT regime. Because of DDT and shock focusing, peak pressures were highest in mixtures that were slightly less sensitive than the detonation threshold. Schlieren movies confirmed the formation of a detonation near the nozzle exit.

  14. Detonation diffraction from an annular channel

    NASA Astrophysics Data System (ADS)

    Meredith, James; Ng, Hoi Dick; Lee, John H. S.

    2010-12-01

    In this study, gaseous detonation diffraction from an annular channel was investigated with a streak camera and the critical pressure for transmission of the detonation wave was obtained. The annular channel was used to approximate an infinite slot resulting in cylindrically expanding detonation waves. Two mixtures, stoichiometric acetylene-oxygen and stoichiometric acetylene-oxygen with 70% Ar dilution, were tested in a 4.3 and 14.3 mm channel width ( W). The undiluted and diluted mixtures were found to have values of the critical channel width over the cell size around 3 and 12 respectively. Comparing these results to values of the critical diameter ( d c ), in which a spherical detonation occurs, a value of critical d c / W c near 2 is observed for the highly diluted mixture. This value corresponds to the geometrical factor of the curvature term between a spherical and cylindrical diverging wave. Hence, the result is in support of Lee's proposed mechanism [Lee in Dynamics of Exothermicity, pp. 321, Gordon and Breach, Amsterdam, 1996] for failure due to diffraction based on curvature in stable mixtures such as those highly argon diluted with very regular detonation cellular patterns.

  15. Structure and properties of detonation soot particles

    SciTech Connect

    MalKOV, I.Y.; Titiov, V.M.

    1996-05-01

    The influence of TNT/RDX (50/50) detonation parameters and conservation conditions of detonation products during their expansion in hermetic detonation chamber on structure and phase composition of the detonation carbon has been considered. Systematic studies made it possible to establish the real structure of detonation carbon depending on experimental conditions. It has been shown that both during explosion in a chamber and thermal annealing in vacuum the nanoparticles of diamond have the tendency to transform not into graphite particles, as was assumed earlier, but into onionlike structures of fullerene series, composed of closed concentric carbon shells, the so-called carbon onions. The nanometer carbon particles have been obtained which comprise a diamond nucleus surrounded by a graphite-like mantle composed of quasi-spherical carbon shells which are the intermediate products of annealing of nanodiamond. The influence of initial sizes of the diamond particles and temperature on the annealing of diamond has been studied. {copyright} {ital 1996 American Institute of Physics.}

  16. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data, including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.

  17. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, H. Douglas; Sung, Chih-Jen

    2003-01-01

    A pulse detonation engine uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Uniform mixing is commonly assumed when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform Hz/air mixtures were analyzed using a two-dimensional Navier-Stokes computational fluid dynamics code with detailed chemistry. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios were studied; one stoichiometric, one fuel lean, and one fuel rich. All mixtures were detonable throughout the detonation tube. Various mixtures representing the same average test section equivalence ratio were shown to have specific impulses within 1% of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance under conditions investigated.

  18. Some observations on the initiation and onset of detonation.

    PubMed

    Thomas, Geraint

    2012-02-13

    The results of experimental studies during which transition to detonation events occurred are presented. These observations and their interpretation are then discussed, and the conditions for the onset of detonation are described, with particular attention paid to the nature of the phenomena of deflagration-to-detonation transition. The resulting implications for predicting detonation evolution using computational fluid dynamic methods in practical applications are also discussed. PMID:22213666

  19. Precursor detonation wave development in ANFO due to aluminum confinement

    SciTech Connect

    Jackson, Scott I; Klyanda, Charles B; Short, Mark

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could decrease the explosive performance by crushing porosity required for initiation by shock compression or destroying confinement ahead of the detonation. At present, these phenomena are not well understood. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understanding and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by a 76-mm-inner-diameter aluminum confining tube. Detonation velocity, detonation-front shape, and aluminum response are recorded as a function of confiner wall thickness and length. Detonation shape profiles display little curvature near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness, while wavefront curvature decreased due to the stiffer, subsonic confinement. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected, which interfered with the front shape measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation by modifying its characteristic shape.

  20. Gas detonation gun for thermal spraying

    SciTech Connect

    Kadyrov, E.; Kadyrov, V.

    1995-08-01

    High-velocity oxy-fuel and gas detonation are competing spray coating processes well known for providing premium quality coatings with low porosity and high adhesion. They are favored for applications in environments of extreme wear, heat, and aggressive corrosion. Nevertheless, they both have limitations. For the HVOF process, these include excessive gas consumption, high rate of heat transfer to the sprayed substrate, and the short life of the (supersonic) Laval nozzle. On the other hand, the traditional gas detonation gun also has drawbacks, and the purpose of this article is to outline some factors that led to the design of an improved gas detonation coating process called Demeton, produced by Demeton USA Inc., Garden City Park, N.Y.

  1. Detonation wave profiles in HMX based explosives

    SciTech Connect

    Gustavsen, R.L.; Sheffield, S.A.; Alcon, R.R.

    1997-11-01

    Detonation wave profiles have been measured in several HMX based plastic bonded explosives including PBX9404, PBX9501, and EDC-37, as well as two HMX powders (coarse and fine) pressed to 65% of crystal density. The powders had 120 and 10 {micro}m average grain sizes, respectively. Planar detonations were produced by impacting the explosive with projectiles launched in a 72-mm bore gas gun. Impactors, impact velocity, and explosive thickness were chosen so that the run distance to detonation was always less than half the explosive thickness. For the high density plastic bonded explosives, particle velocity wave profiles were measured at an explosive/window interface using two VISAR interferometers. PMMA windows with vapor deposited aluminum mirrors were used for all experiments. Wave profiles for the powdered explosives were measured using magnetic particle velocity gauges. Estimates of the reaction zone parameters were obtained from the profiles using Hugoniots of the explosive and window.

  2. Multistage reaction pathways in detonating high explosives

    SciTech Connect

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Nomura, Ken-ichi; Vashishta, Priya

    2014-11-17

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N{sub 2} and H{sub 2}O within ∼10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct unimolecular and intermolecular reaction pathways, respectively, for the rapid N{sub 2} and H{sub 2}O productions.

  3. Detonation Properties of Ammonium Dinitramide (ADN)

    NASA Astrophysics Data System (ADS)

    Wätterstam, A.; Östmark, H.; Helte, A.; Karlsson, S.

    1999-06-01

    Ammonium Dinitramide, ADN, has a potential as an oxidizer for underwater high explosives. Pure ADN has a large reaction-zone length and shows a strong non-ideal behaviour. The work presented here is an extension of previous work.(Sensitivity and Performance Characterization of Ammonium Dinitramide (ADN). Presented at 11th International Detonation Symposium, Snowmass, CO, 1998.) Experiments for determining the detonation velocity as a function of inverse charge radius and density, reaction-zone length and curvature, and the detonation pressure are presented. Measurements of pressure indicates that no, or weak von-Neumann spike exists, suggesting an immediate chemical decomposition. Experimental data are compared with predicted using thermochemical codes and ZND-theory.

  4. Detonation Performance Testing of LX-19

    NASA Astrophysics Data System (ADS)

    Vincent, Samuel; Aslam, Tariq; Jackson, Scott

    2015-06-01

    CL-20 was developed at the Naval Surface Weapons Center at China Lake, CA in the mid 80's. Being less sensitive than PETN, but considerably more powerful than HMX, it is the highest energy and density compound known among organic chemicals. LX-19 was developed at LLNL in the early 90's. It is a high-energy plastic bonded explosive, composed of 95.8 wt% CL-20 and 4.2 wt% Estane binder, and is similar to LX-14 (composed of HMX and Estane), but with greater sensitivity characteristics with use of the more energetic CL-20 explosive. We report detonation performance results for unconfined cylindrical rate sticks of LX-19. The experimental diameter effects are shown, along with detonation front shapes, and reaction zone profiles for different test diameters. This data is critical for calibration to Detonation Shock Dynamics (DSD). LA-UR-15-20672.

  5. Eigenvalue Detonation of Combined Effects Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Capellos, Christos; Baker, Ernest; Balas, Wendy; Nicolich, Steven; Stiel, Leonard

    2007-06-01

    This paper reports on the development of theory and performance for recently developed combined effects aluminized explosives. Traditional high energy explosives used for metal pushing incorporate high loading percentages of HMX or RDX, whereas blast explosives incorporate some percentage of aluminum. However, the high blast explosives produce increased blast energies, with reduced metal pushing capability due to late time aluminum reaction. Metal pushing capability refers to the early volume expansion work produced during the first few volume expansions associated with cylinder wall velocities and Gurney energies. Our Recently developed combined effects aluminized explosives (PAX-29C, PAX-30, PAX-42) are capable of achieving excellent metal pushing and high blast energies. Traditional Chapman-Jouguet detonation theory does not explain the observed detonation states achieved by these combined effects explosives. This work demonstrates, with the use of cylinder expansion data and thermochemical code calculations (JAGUAR and CHEETAH), that eigenvalue detonation theory explains the observed behavior.

  6. Pulse Detonation Engine Test Bed Developed

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin J.

    2002-01-01

    A detonation is a supersonic combustion wave. A Pulse Detonation Engine (PDE) repetitively creates a series of detonation waves to take advantage of rapid burning and high peak pressures to efficiently produce thrust. NASA Glenn Research Center's Combustion Branch has developed a PDE test bed that can reproduce the operating conditions that might be encountered in an actual engine. It allows the rapid and cost-efficient evaluation of the technical issues and technologies associated with these engines. The test bed is modular in design. It consists of various length sections of both 2- and 2.6- in. internal-diameter combustor tubes. These tubes can be bolted together to create a variety of combustor configurations. A series of bosses allow instrumentation to be inserted on the tubes. Dynamic pressure sensors and heat flux gauges have been used to characterize the performance of the test bed. The PDE test bed is designed to utilize an existing calorimeter (for heat load measurement) and windowed (for optical access) combustor sections. It uses hydrogen as the fuel, and oxygen and nitrogen are mixed to simulate air. An electronic controller is used to open the hydrogen and air valves (or a continuous flow of air is used) and to fire the spark at the appropriate times. Scheduled tests on the test bed include an evaluation of the pumping ability of the train of detonation waves for use in an ejector and an evaluation of the pollutants formed in a PDE combustor. Glenn's Combustion Branch uses the National Combustor Code (NCC) to perform numerical analyses of PDE's as well as to evaluate alternative detonative combustion devices. Pulse Detonation Engine testbed.

  7. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Transporting explosives and detonators. 75.1311... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1311 Transporting explosives and detonators. (a) When explosives and detonators are to be transported...

  8. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics....

  9. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics....

  10. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics....

  11. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics....

  12. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar...

  13. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar...

  14. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar...

  15. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics....

  16. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar...

  17. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar...

  18. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current...

  19. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current...

  20. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current...

  1. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as...

  2. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as...

  3. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as...

  4. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Transporting explosives and detonators. 75.1311... Transporting explosives and detonators. (a) When explosives and detonators are to be transported underground... transported by any cars or vehicles— (1) The cars or vehicles shall be marked with warnings to identify...

  5. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Transporting explosives and detonators. 75.1311... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1311 Transporting explosives and detonators. (a) When explosives and detonators are to be transported...

  6. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Transporting explosives and detonators. 75.1311... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1311 Transporting explosives and detonators. (a) When explosives and detonators are to be transported...

  7. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Transporting explosives and detonators. 75.1311... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1311 Transporting explosives and detonators. (a) When explosives and detonators are to be transported...

  8. Feasibility and parameter study of a detonation diffuser

    NASA Astrophysics Data System (ADS)

    Stevens, Christopher A.

    This research includes an investigation of the mechanisms of diffraction and reinitiation that enable a detonation diffuser. It describes a set of geometric parameters necessary to design a diffuser for a given detonable mixture and initial channel height. Predetonators with channel height less than the critical height are ineffective because detonations in small channels decouple into separate shock and combustion fronts when the channel height increases. A detonation diffuser allows the channel height to increase by utilizing the decoupled shock wave to reinitiate detonation. In the diffuser, a detonation initially decouples into separate shock and combustion fronts, and then the decoupled shock front reflects from an oblique surface initiating a secondary detonation that survives the expansion. This research investigated the three regions of a detonation diffuser: the initial diffraction, the reflecting surface, and the second diffraction corner. Schlieren video of two-dimensional diffracting detonations recorded the position of the detonation, decoupled shock front and flame front. Observations of the decoupled shocks reflecting from surfaces showed that a 45° reflecting surface must be placed less than 80 mm downstream of the initial diffraction corner to initiate a secondary detonation in more than 91% of repeated trials. Observations of the interaction of diffracting detonations with multiple obstacles revealed that the best performance (smallest separation, and highest Mach number) occurred when the decoupled shock reflected from four separate obstacles at approximately the same time.

  9. Modeling Initiation in Exploding Bridgewire Detonators

    SciTech Connect

    Hrousis, C A

    2005-05-18

    One- and two-dimensional models of initiation in detonators are being developed for the purpose of evaluating the performance of aged and modified detonator designs. The models focus on accurate description of the initiator, whether it be an EBW (exploding bridgewire) that directly initiates a high explosive powder or an EBF (exploding bridgefoil) that sends an inert flyer into a dense HE pellet. The explosion of the initiator is simulated using detailed MHD equations of state as opposed to specific action-based phenomenological descriptions. The HE is modeled using the best available JWL equations of state. Results to date have been promising, however, work is still in progress.

  10. Statistical Hot Spot Model for Explosive Detonation

    SciTech Connect

    Nichols, III, A L

    2005-07-14

    The Non-local Thermodynamic Equilibrium Statistical Hot Spot Model (NLTE SHS), a new model for explosive detonation, is described. In this model, the formation, ignition, propagation, and extinction of hot spots is explicitly modeled. The equation of state of the explosive mixture is treated with a non-local equilibrium thermodynamic assumption. A methodology for developing the parameters for the model is discussed, and applied to the detonation velocity diameter effect. Examination of these results indicates where future improvements to the model can be made.

  11. Statistical Hot Spot Model for Explosive Detonation

    SciTech Connect

    Nichols III, A L

    2004-05-10

    The Non-local Thermodynamic Equilibrium Statistical Hot Spot Model (NLTE SHS), a new model for explosive detonation, is described. In this model, the formation, ignition, propagation, and extinction of hot spots is explicitly modeled. The equation of state of the explosive mixture is treated with a nonlocal equilibrium thermodynamic assumption. A methodology for developing the parameters for the model is discussed, and applied to the detonation velocity diameter effect. Examination of these results indicates where future improvements to the model can be made.

  12. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, A.; Othmer, P.; Rostafinski, W.

    1992-01-01

    An experimental demonstration is presented for the generation of detonation waves that move periodically across high speed channel flow; these waves can compress the outflow from a low pressure compressor, and thereby both reduce the compressor requirements associated with conventional gas turbines and enhance thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock-wave losses are reduced by an order of magnitude; the result is a Humphrey cycle augmenting the basic Brayton-cycle gas turbine. Attention is presently given to results from an experimental detonation duct.

  13. Pressure Feedback in Rotating Detonation Engines

    NASA Astrophysics Data System (ADS)

    Schwer, Douglas; Kailasanath, K.

    2012-11-01

    Rotating detonation engines (RDEs) represent a unique method for obtaining propulsion from the high efficiency detonation cycle. In order for the RDE to be a practical propulsive device, engines must be capable of running efficiently at low pressure ratios, however, this type of injection typically results in a large amount of pressure feedback into the injection system. This paper examines different aspects of the pressure feedback phenomena, and investigates approaches to injecting fresh mixture that reduce the amount of feedback. This work is supported by the Office of Naval Research through NRL 6.1 Computational Physics Task Area.

  14. Selection of operating machinery parameters for a bucket excavator

    SciTech Connect

    Fabrichnyi, Y.F.; Baboshin, K.V.; Etinger, I.M.; Mekk, V.A.

    1985-05-01

    The mining industry uses extensively single-bucket excavators of the straight shovel type, like the EKG-4.6, as the most effective way of loading previously loosened hard and abrasive excavated rocks. Therefore, an increase in their working efficiency, mainly as regards increasing productivity, reducing load on the operating machinery, and reducing wear of the operating machinery elements, is of particular importance. Analysis shows that the possibilities for this lie in the correct selection of movement trajectory parameters for the excavator bucket, which for existing excavators are inadequate for loading excavated rock. The authors study here the effect of trajectory parameters on excavator bucket filling, and on their basis they select parameters for the operating machinery.

  15. Effect of Velocity of Detonation of Explosives on Seismic Radiation

    NASA Astrophysics Data System (ADS)

    Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

    2014-12-01

    We studied seismic body wave generation from four fully contained explosions of approximately the same yields (68 kg of TNT equivalent) conducted in anisotropic granite in Barre, VT. The explosions were detonated using three types of explosives with different velocities of detonation (VOD): Black Powder (BP), Ammonium Nitrate Fuel Oil/Emulsion (ANFO), and Composition B (COMP B). The main objective of the experiment was to study differences in seismic wave generation among different types of explosives, and to determine the mechanism responsible for these differences. The explosives with slow burn rate (BP) produced lower P-wave amplitude and lower corner frequency, which resulted in lower seismic efficiency (0.35%) in comparison with high burn rate explosives (2.2% for ANFO and 3% for COMP B). The seismic efficiency estimates for ANFO and COMP B agree with previous studies for nuclear explosions in granite. The body wave radiation pattern is consistent with an isotropic explosion with an added azimuthal component caused by vertical tensile fractures oriented along pre-existing micro-fracturing in the granite, although the complexities in the P- and S-wave radiation patterns suggest that more than one fracture orientation could be responsible for their generation. High S/P amplitude ratios and low P-wave amplitudes suggest that a significant fraction of the BP source mechanism can be explained by opening of the tensile fractures as a result of the slow energy release.

  16. Quantum phenomena in ignition and detonation at elevated density.

    PubMed

    Drakon, A V; Emelianov, A V; Eremin, A V; Gurentsov, E V; Petrushevich, Yu V; Starostin, A N; Taran, M D; Fortov, V E

    2012-11-01

    The influence of quantum effects on the processes of initiation of combustion and detonation of hydrogen and acetylene near the low-temperature limits at elevated pressures is analyzed. A theoretical consideration which allows quantification of the quantum corrections to the rate constants of endothermic reactions associated with an increase in the high-energy tail of the equilibrium momentum distribution function at high pressures is presented. This quantum effect is caused by a manifestation of the principle of uncertainty for the energy of the colliding particles at a high frequency of collisions. It is shown that significant deviations of experimentally observed ignition and detonation delay time from the predictions of kinetic calculations are quite well described by the proposed quantum corrections. This general mechanism should be considered in the safety problem with emergency emissions of hydrogen at nuclear power stations, as well as problems of the safe production and storage of hydrogen and acetylene, which have a fundamental importance for industry and power engineering. PMID:23215276

  17. Radiation measurements of excavated items at a radioactive-waste burial site

    NASA Astrophysics Data System (ADS)

    Stromswold, D. C.; Alvarez, J. L.; Ludowise, J. D.

    1995-12-01

    Radiation measurements on items excavated from a radioactive-waste burial ground were part of a field test of excavation techniques for the cleanup of subsurface sites. The waste resulted from plutonium production for nuclear weapons at Hanford, WA. The radiation measurements investigated techniques for classifying bulk waste for placement into a permanent disposal facility. Hand-held γ-ray survey instruments measured exposure rates (mR/h) from contaminated dirt and radioactive objects as they were removed by heavy excavation equipment. Gamma-ray detectors mounted on the excavation equipment provided additional data that were transmitted by radio. Exposure rates from identifiable objects (e.g. specific reactor components) were compared with expected exposure rates calculated from site-disposal records and computer modeling. Selected objects were subjected to additional on-site measurements using a high-purity germanium detector. Detected nuclides included 60Co, 137Cs, 152,154Eu, and 108mAg. A large-volume neutron detector checked for possible transuranic nuclides. Alpha and β spectrometry also were tested. but their utility for this application was limited due to the short range of the particles and the difficulty of maintaining a repeatable measurement geometry in the field.

  18. Offsite radiological consequence analysis for the bounding unplanned excavation/drilling of 200 area soils

    SciTech Connect

    STEPHENS, L.S.

    2003-03-21

    This analysis calculates the offsite radiological consequence of the bounding unplanned excavation/drilling of 200 Area soils accident. The US. Department of Energy (DOE) standard DOE-STD-3009-94, ''Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented Safety Analyses'', requires the formal quantification of a limited subset of accidents representing a complete set of bounding conditions. The results of these analyses are then evaluated to determine if they challenge the DOE-STD-3009-94 Appendix A, ''Evaluation Guideline,'' of 25 rem total effective dose equivalent to identify and evaluate safety-class structures, systems, and components. This document supports the development of the unplanned excavation/drilling of 200 Area soils accident in the tank farm documented safety analysis. Consequently, it: (1) Provides a comprehensive review of potential unplanned excavation scenarios (i.e., backhoe, buried pressurized line ruptures, drilling, Guzzler vacuum) to determine the representative activity that would bound unmitigated, unplanned, or inadvertent excavations of 200 Area soils. (2) Evaluates radiological isotope inventories of all current Tank Farm Contractor (TFC) liquid waste disposal sites [i.e., cribs, ditches, and ponds (including French drains)], and isotope inventories of unplanned release sites (UPR) and plume columns. (3) Establishes the radiological consequences to the maximum offsite individual (MOI) from an unplanned/inadvertent 200 Area soil disturbance based on bounding site development and representative accident determination.

  19. Excavation and rock breaking system on the moon

    NASA Astrophysics Data System (ADS)

    Shimizu, Katsunori; Yoshida, Tetsuji; Kai, Yoshiro; Mano, Hideyuki; Takagi, Kenji; Matsumoto, Shinji

    The construction of lunar bases underground, in order to escape cosmic rays and small meteorites, entails lunar regolith soil-excavation equipment capable of both rock fracture and the subsequent processing of the mineral detritus from excavation sites. Consideration is given to excavation systems' power supplies, heat removal, mechanical bearings, vehicular platform, conveyor belts, and tool accessories. An evaluation is made of the enabling technologies required for such devices' implementation.

  20. Focal Choroidal Excavation in Best Vitelliform Macular Dystrophy: Case Report.

    PubMed

    Esfahani, Mohammad Riazi; Esfahani, Hamid Riazi; Mahmoudi, Alireza; Johari, Mohammad Karim; Hemati, Karim

    2015-05-01

    Focal choroidal excavation (FCE) was first reported as a choroidal posteriorly excavated zone without any scleral change. Choroidal excavation also divided into conforming and nonconforming type. Numerous reports demonstrated association between FCE and other disease such as choroidal neovascularization and central serous choroidoretinopathy. Here, we report a rare case of FCE in a patient with Best disease. The patient was diagnosed by spectoral domain optical coherence tomography (SD-OCT). To the best of our knowledge, our patient is the second report of choroidal excavation in Best vitelliform macular dystrophy. PMID:26155505

  1. Focal Choroidal Excavation in Best Vitelliform Macular Dystrophy: Case Report

    PubMed Central

    Esfahani, Mohammad Riazi; Esfahani, Hamid Riazi; Mahmoudi, Alireza; Johari, Mohammad Karim

    2015-01-01

    Focal choroidal excavation (FCE) was first reported as a choroidal posteriorly excavated zone without any scleral change. Choroidal excavation also divided into conforming and nonconforming type. Numerous reports demonstrated association between FCE and other disease such as choroidal neovascularization and central serous choroidoretinopathy. Here, we report a rare case of FCE in a patient with Best disease. The patient was diagnosed by spectoral domain optical coherence tomography (SD-OCT). To the best of our knowledge, our patient is the second report of choroidal excavation in Best vitelliform macular dystrophy. PMID:26155505

  2. Laterally Propagating Detonations in Thin Helium Layers on Accreting White Dwarfs

    NASA Astrophysics Data System (ADS)

    Townsley, Dean M.; Moore, Kevin; Bildsten, Lars

    2012-08-01

    Theoretical work has shown that intermediate mass (0.01 M ⊙ < M He < 0.1 M ⊙) helium shells will unstably ignite on the accreting white dwarf (WD) in an AM CVn binary. For more massive (M > 0.8 M ⊙) WDs, these helium shells can be dense enough (>5 × 105 g cm-3) that the convectively burning region runs away on a timescale comparable to the sound travel time across the shell, raising the possibility for an explosive outcome rather than an Eddington limited helium novae. The nature of the explosion (i.e., deflagration or detonation) remains ambiguous, is certainly density dependent, and likely breaks spherical symmetry. In the case of detonation, this causes a laterally propagating front whose properties in these geometrically thin and low-density shells we begin to study here. Our calculations show that the radial expansion time of <0.1 s leads to incomplete helium burning, in agreement with recent work by Sim and collaborators, but that the nuclear energy released is still adequate to realize a self-sustaining laterally propagating detonation. These detonations are slower than the Chapman-Jouguet speed of 1.5 × 109 cm s-1, but still fast enough at 0.9 × 109 cm s-1 to go around the star prior to the transit through the star of the inwardly propagating weak shock. Our simulations resolve the subsonic region behind the reaction front in the detonation wave. The two-dimensional nucleosynthesis is shown to be consistent with a truncated one-dimensional Zeldovich-von Neumann-Döring calculation at the slower detonation speed. The ashes from the lateral detonation are typically He rich, and consist of predominantly 44Ti, 48Cr, along with a small amount of 52Fe, with very little 56Ni and with significant 40Ca in carbon-enriched layers. If this helium detonation results in a Type Ia supernova, its spectral signatures would appear for the first few days after explosion.

  3. LATERALLY PROPAGATING DETONATIONS IN THIN HELIUM LAYERS ON ACCRETING WHITE DWARFS

    SciTech Connect

    Townsley, Dean M.; Moore, Kevin; Bildsten, Lars

    2012-08-10

    Theoretical work has shown that intermediate mass (0.01 M{sub Sun} < M{sub He} < 0.1 M{sub Sun }) helium shells will unstably ignite on the accreting white dwarf (WD) in an AM CVn binary. For more massive (M > 0.8 M{sub Sun }) WDs, these helium shells can be dense enough (>5 Multiplication-Sign 10{sup 5} g cm{sup -3}) that the convectively burning region runs away on a timescale comparable to the sound travel time across the shell, raising the possibility for an explosive outcome rather than an Eddington limited helium novae. The nature of the explosion (i.e., deflagration or detonation) remains ambiguous, is certainly density dependent, and likely breaks spherical symmetry. In the case of detonation, this causes a laterally propagating front whose properties in these geometrically thin and low-density shells we begin to study here. Our calculations show that the radial expansion time of <0.1 s leads to incomplete helium burning, in agreement with recent work by Sim and collaborators, but that the nuclear energy released is still adequate to realize a self-sustaining laterally propagating detonation. These detonations are slower than the Chapman-Jouguet speed of 1.5 Multiplication-Sign 10{sup 9} cm s{sup -1}, but still fast enough at 0.9 Multiplication-Sign 10{sup 9} cm s{sup -1} to go around the star prior to the transit through the star of the inwardly propagating weak shock. Our simulations resolve the subsonic region behind the reaction front in the detonation wave. The two-dimensional nucleosynthesis is shown to be consistent with a truncated one-dimensional Zeldovich-von Neumann-Doering calculation at the slower detonation speed. The ashes from the lateral detonation are typically He rich, and consist of predominantly {sup 44}Ti, {sup 48}Cr, along with a small amount of {sup 52}Fe, with very little {sup 56}Ni and with significant {sup 40}Ca in carbon-enriched layers. If this helium detonation results in a Type Ia supernova, its spectral signatures would

  4. Detonation of hydrogen-air mixtures. [PWR; BWR

    SciTech Connect

    Lee, J.H.S.; Knystautas, R.; Benedick, W.B.

    1983-01-01

    The detonation of a hydrogen-air cloud subsequent to an accidental release of hydrogen into ambient surroundings cannot be totally ruled out in view of the relative sensitivity of the hydrogen-air system. The present paper investigates the key parameters involved in hydrogen-air detonations and attempts to establish quantitative correlations between those that have important practical implications. Thus, for example, the characteristic length scale lambda describing the cellular structure of a detonation front is measured for a broad range of hydrogen-air mixtures and is quantitatively correlated with the key dynamic detonation properties such as detonability, transmission and initiation.

  5. Vulnerability assessment of a space based weapon platform electronic system exposed to a thermonuclear weapon detonation

    SciTech Connect

    Perez, C.L.; Johnson, J.O.

    1994-03-01

    Rapidly changing world events, the increased number of nations with inter-continental ballistic missile capability, and the proliferation of nuclear weapon technology will increase the number of nuclear threats facing the world today. Monitoring these nation`s activities and providing an early warning and/or intercept system via reconnaissance and surveillance satellites and space based weapon platforms is a viable deterrent against a surprise nuclear attack. However, the deployment of satellite and weapon platform assets in space will subject the sensitive electronic equipment to a variety of natural and man-made radiation environments. These include Van Allen Belt protons and electrons; galactic and solar flare protons; and, neutrons, gamma rays, and X-rays from intentionally detonated fission and fusion weapons. In this paper, the MASH vl.0 code system is used to estimate the dose to the critical electronics components of an idealized space based weapon platform from neutron and gamma-ray radiation emitted from a thermonuclear weapon detonation in space. Fluence and dose assessments were performed for the platform fully loaded, and in several stages representing limited engagement scenarios. The results indicate vulnerabilities to the Command, Control, and Communication (C) bay instruments from radiation damage for a nuclear weapon detonation for certain source/platform orientations. The distance at which damage occurs will depend on the weapon yield (n,{gamma}/kiloton) and size (kilotons).

  6. Ethylene-air detonation in water spray

    NASA Astrophysics Data System (ADS)

    Jarsalé, G.; Virot, F.; Chinnayya, A.

    2016-07-01

    Detonation experiments are conducted in a 52 mm square channel with an ethylene-air gaseous mixture with dispersed liquid water droplets. The tests were conducted with a fuel-air equivalence ratio ranging from 0.9 to 1.1 at atmospheric pressure. An ultrasonic atomizer generates a polydisperse liquid water spray with droplet diameters of 8.5-12 μm, yielding an effective density of 100-120 g/m3 . Pressure signals from seven transducers and cellular structure are recorded for each test. The detonation structure in the two-phase mixture exhibits a gaseous-like behaviour. The pressure profile in the expansion fan is not affected by the addition of water. A small detonation velocity deficit of up to 5 % was measured. However, the investigation highlights a dramatic increase in the cell size (λ ) associated with the increase in the liquid water mass fraction in the two-phase mixture. The detonation structure evolves from a multi-cell to a half-cell mode. The analysis of the decay of the post-shock pressure fluctuations reveals that the ratio of the hydrodynamic thickness over the cell size (x_{{HT}}/{λ } ) remains quite constant, between 5 and 7. A slight decrease of this ratio is observed as the liquid water mass fraction is increased, or the ethylene-air mixture is made leaner.

  7. Detonation propagation in a high loss configuration

    SciTech Connect

    Jackson, Scott I; Shepherd, Joseph E

    2009-01-01

    This work presents an experimental study of detonation wave propagation in tubes with inner diameters (ID) comparable to the mixture cell size. Propane-oxygen mixtures were used in two test section tubes with inner diameters of 1.27 mm and 6.35 mm. For both test sections, the initial pressure of stoichiometric mixtures was varied to determine the effect on detonation propagation. For the 6.35 mm tube, the equivalence ratio {phi} (where the mixture was {phi} C{sub 3}H{sub 8} + 50{sub 2}) was also varied. Detonations were found to propagate in mixtures with cell sizes as large as five times the diameter of the tube. However, under these conditions, significant losses were observed, resulting in wave propagation velocities as slow as 40% of the CJ velocity U{sub CJ}. A review of relevant literature is presented, followed by experimental details and data. Observed velocity deficits are predicted using models that account for boundary layer growth inside detonation waves.

  8. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, Andrew; Brinlee, Gayl A.; Othmer, Peter; Whelan, Michael A.

    1991-01-01

    The feasibility of the generation of detonation waves moving periodically across high speed channel flow is experimentally demonstrated. Such waves are essential to the concept of compressing requirements and increasing the engine pressure compressor with the objective of reducing conventional compressor requirements and increasing the engine thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock wave losses are reduced by an order of magnitude. The ultimate objective is to use such detonation ducts downstream of a low pressure gas turbine compressor to produce a high overall pressure ratio thermodynamic cycle. A 4 foot long, 1 inch x 12 inch cross-section, detonation duct was operated in a blow-down mode using compressed air reservoirs. Liquid or vapor propane was injected through injectors or solenoid valves located in the plenum or the duct itself. Detonation waves were generated when the mixture was ignited by a row of spark plugs in the duct wall. Problems with fuel injection and mixing limited the air speeds to about Mach 0.5, frequencies to below 10 Hz, and measured pressure ratios of about 5 to 6. The feasibility of the gas dynamic compression was demonstrated and the critical problem areas were identified.

  9. Detonation and deflagration properties of pyrotechnic mixtures

    SciTech Connect

    Tanaka, Katsumi

    1996-07-01

    Theoretical calculation of detonation and deflagration properties of pyrotechnic mixtures have been performed including report charges and display charges. Calculation were performed with the KHT (Kihara-Hikta-Tanaka) code. KHT results are compared with a modified version of the TIGER code which allows calculation with 900 gaseous and 600 condensed product species at high pressure. Detonation properties computed by KHT and BKWS (Becker-Kistiakowskii-Wilson) give favorable agreement with experimental results of detonation velocity measurements. Hydrodynamic computation by one dimensional Lagrangian hydrodynamic code using the isentrope given by KHT constant volume explosion, indicated that experimental results for blast wave measurement for 30kg and 50kg of report charge were an incomplete reaction. Underwater detonation experiments with explosive charge of 25g, however, indicates a more energetic nature than the KHT prediction. This scale effect indicates complicated slow reactions and a number of condensed phase deflagration products of powder mixtures such as aluminum or titanium with oxidizers such as potassium perchlorate or nitrate salts as suggested by Hobbs et al.

  10. Hydrogen detonation and detonation transition data from the High-Temperature Combustion Facility

    SciTech Connect

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.; Gerlach, L.; Tagawa, H.; Malliakos, A.

    1995-12-31

    The BNL High-Temperature Combustion Facility (HTCF) is an experimental research tool capable of investigating the effects of initial thermodynamic state on the high-speed combustion characteristic of reactive gas mixtures. The overall experimental program has been designed to provide data to help characterize the influence of elevated gas-mixture temperature (and pressure) on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for flames accelerating in these mixtures to transition into detonations, on the effects of gas venting on the flame-accelerating process, on the phenomena of initiation of detonations in these mixtures by jets of hot reactant product,s and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below.

  11. Hydrogen detonation and detonation transition data from the High-Temperature Combustion Facility

    SciTech Connect

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.

    1996-03-01

    The BNL High-Temperature Combustion Facility (HTCF) is an experimental research tool capable of investigating the effects of initial thermodynamic state on the high-speed combustion characteristic of reactive gas mixtures. The overall experimental program has been designed to provide data to help characterize the influence of elevated gas-mixture temperature (and pressure) on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for flames accelerating in these mixtures to transition into detonations, on the effects of gas venting on the flame-accelerating process, on the phenomena of initiation of detonations in these mixtures by jets of hot reactant products, and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below.

  12. Detonation and Transition to Detonation in Horizontal Water-Filled Pipes

    NASA Astrophysics Data System (ADS)

    Bitter, Neal P.; Shepherd, Joseph E.

    2012-11-01

    Detonations and deflagration-to-detonation transition (DDT) are experimentally studied in horizontal pipes which are partially filled with water. The gas layer above the water is stoichiometric hydrogen-oxygen at 1 bar. The detonation wave produces oblique shock waves in the water, which focus at the bottom of the pipe due to the curvature of the walls. This results in peak pressures at the bottom of the pipe that are 4-6 times greater than the peak detonation pressure. Such pressure amplification is measured for water depths of 0.25, 0.5, 0.75, 0.87, and 0.92 pipe diameters. Focusing of the oblique shock waves is studied further by measuring the circumferential variation of pressure when the water depth is 0.5 pipe diameters, and reasonable agreement with theoretical modeling is found. Failure of the detonation waves was not observed, even for water depths as high as 0.92 pipe diameters. Transition to detonation also occurred at every water height, and transition distance did not vary significantly with water height.

  13. Modelling bucket excavation by finite element

    NASA Astrophysics Data System (ADS)

    Pecingina, O. M.

    2015-11-01

    Changes in geological components of the layers from lignite pits have an impact on the sustainability of the cup path elements and under the action of excavation force appear efforts leading to deformation of the entire assembly. Application of finite element method in the optimization of components leads to economic growth, to increase the reliability and durability of the studied machine parts thus the machine. It is obvious usefulness of knowledge the state of mechanical tensions that the designed piece or the assembly not to break under the action of tensions that must cope during operation. In the course of excavation work on all bucket cutting force components, the first coming into contact with the material being excavated cutting edge. Therefore in the study with finite element analysis is retained only cutting edge. To study the field of stress and strain on the cutting edge will be created geometric patterns for each type of cup this will be subject to static analysis. The geometric design retains the cutting edge shape and on this on the tooth cassette location will apply an areal force on the abutment tooth. The cutting edge real pattern is subjected to finite element study for the worst case of rock cutting by symmetrical and asymmetrical cups whose profile is different. The purpose of this paper is to determine the displacement and tensions field for both profiles considering the maximum force applied on the cutting edge and the depth of the cutting is equal with the width of the cutting edge of the tooth. It will consider the worst case when on the structure will act both the tangential force and radial force on the bucket profile. For determination of stress and strain field on the form design of cutting edge profile will apply maximum force assuming uniform distribution and on the edge surface force will apply a radial force. After geometric patterns discretization on the cutting knives and determining stress field, can be seen that at the

  14. Cellular structure of detonation utilized in propulsion system

    NASA Astrophysics Data System (ADS)

    Zhang, XuDong; Fan, BaoChun; Gui, MingYue; Pan, ZhenHua

    2012-10-01

    How to confine a detonation in a combustor is a key issue of detonation applications in propulsion systems. Based on achieving schemes, detonations applied in the combustor, including pulse detonation wave (PDW), oblique detonation wave (ODW) and rotating detonation wave (RDW), are different from that described by the classic CJ theory in fine structures and its self-sustaining mechanisms. In this work, the cellular structures and flow fields of ODW and RDW were obtained numerically, and the fundamental characteristics and self-sustaining mechanisms of the detonations were analyzed and discussed. ODW front consists of three parts: the ZND-like front, the single-headed triple point front and the dual-headed triple point front. Cellular structures of RDW are heterogeneous, and the cell size near the outer wall is smaller than that near the inner wall.

  15. The flow field in a rotating detonation-wave engine

    NASA Astrophysics Data System (ADS)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2011-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engine. They potentially provide further gains than an intermittent or pulsed detonation-wave engine (PDE). However, significantly less work has been on this concept when compared to the PDE. In this talk, we present the detailed flow field in an idealized RDE, primarily consisting of two concentric cylinders. A premixed detonable mixture is injected into the annulus between the two concentric cylinders. Once a detonation is initiated, it keeps travelling around in the annulus as long as there is fresh detonable mixture ahead of it. Hence, the injection process is critically important to the stability and performance of the RDE. Furthermore, we show that the flow field is quite complex consisting of multiple shock waves and the outflow is primarily axial, although the detonation-wave is travelling around circumferentially. Sponsored by the NRL 6.1 Computational Physics Task Area.

  16. Synchro-ballistic recording of detonation phenomena

    SciTech Connect

    Critchfield, R.R.; Asay, B.W.; Bdzil, J.B.; Davis, W.C.; Ferm, E.N.; Idar, D.J.

    1997-09-01

    Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.

  17. 118-B-1 excavation treatability test procedures

    SciTech Connect

    Frain, J.M.

    1994-08-01

    This treatability study has two purposes: to support development of the approach to be used for burial ground remediation, and to provide specific engineering information for the design of burial grounds receiving waste generated from the 100 Area removal actions. Data generated from this test will also provide performance and cost information necessary for detailed analysis of alternatives for burial ground remediation. Further details on the test requirements, milestones and data quality objectives are described in detail in the 118-B-1 Excavation Treatability Test Plan (DOE/RL-94-43). These working procedures are intended for use by field personnel to implement the requirements of the milestone. A copy of the detailed Test Plan will be kept on file at the on-site field support trailer, and will be available for review by field personnel.

  18. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Unknown

    2001-10-12

    The hypothesis to be tested is that the addition of steel or other synthetic fiber and/or high strength, low cost aggregate to strong grouts or concrete will result in a projectile of sufficient strength to produce cracking and spall enough to make its use cost effective for mining. Based on experiments conducted to date, no conclusions can yet be reached. Results of the experiments conducted suggest that reinforcement of a concrete projectile can yield performance that portends cost effective projectile based excavation. It is recognized that the projectile is but one component of the matrix. The electric launch system to be developed in the next phase of the program is the other factor that weighs heavily in the cost effectiveness equation. At this point, however, emerging low cost options for the projectile are very promising.

  19. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  20. Experimental Investigation of Detonation Re-initiation Mechanisms Following a Mach Reflection of a Quenched Detonation

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Rohit Ranjan

    Detonation waves are supersonic combustion waves that have a multi-shock front structure followed by a spatially non-uniform reaction zone. During propagation, a de-coupled shock-flame complex is periodically re-initiated into an overdriven detonation following a transient Mach reflection process. Past researchers have identified mechanisms that can increase combustion rates and cause localized hot spot re-ignition behind the Mach shock. But due to the small length scales and stochastic behaviour of detonation waves, the important mechanisms that can lead to re-initiation into a detonation requires further clarification. If a detonation is allowed to diffract behind an obstacle, it can quench to form a de-coupled shock-flame complex and if allowed to form a Mach reflection, re-initiation of a detonation can occur. The use of this approach permits the study of re-initiation mechanisms reproducibly with relatively large length scales. The objective of this study is to experimentally elucidate the key mechanisms that can increase chemical reaction rates and sequentially lead to re-initiation of a de-coupled shock-flame complex into an overdriven detonation wave following a Mach reflection. All experiments were carried out in a thin rectangular channel using a stoichiometric mixture of oxy-methane. Three different types of obstacles were used - a half-cylinder, a roughness plate along with the half-cylinder and a full-cylinder. Schlieren visualization was achieved by using a Z-configuration setup, a high speed camera and a high intensity light source. Results indicate that forward jetting of the slip line behind the Mach stem can potentially increase combustion rates by entraining hot burned gas into unburned gas. Following ignition and jet entrainment, a detonation wave first appears along the Mach stem. The transverse wave can form a detonation wave due to rapid combustion of unburned gas which may be attributed to shock interaction with the unburned gas

  1. 29 CFR 1926.651 - Specific excavation requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... subparts D and E of this part (29 CFR 1926.50-1926.107) to prevent exposure to harmful levels of.... (f) Warning system for mobile equipment. When mobile equipment is operated adjacent to an excavation... have a clear and direct view of the edge of the excavation, a warning system shall be utilized such...

  2. Characterization Of High Explosives Detonations Via Laser-Induced Plasmas

    SciTech Connect

    Villa-Aleman, E.

    2015-10-08

    One objective of the Department of Energy’s National Security Administration is to develop technologies that can help the United States government to detect foreign nuclear weapons development activities. The realm of high explosive (HE) experiments is one of the key areas to assess the nuclear ambitions of a country. SRNL has participated in the collection of particulates from HE experiments and characterized the material with the purpose to correlate particulate matter with HE. Since these field campaigns are expensive, on-demand simulated laboratory-scale explosion experiments are needed to further our knowledge of the chemistry and particle formation in the process. Our goal is to develop an experimental test bed in the laboratory to test measurement concepts and correlate particle formation processes with the observables from the detonation fireball. The final objective is to use this knowledge to tailor our experimental setups in future field campaigns. The test bed uses pulsed laser-induced plasmas to simulate micro-explosions, with the intent to study the temporal behavior of the fireball observed in field tests. During FY15, a plan was prepared and executed which assembled two laser ablation systems, procured materials for study, and tested a Step-Scan Fourier Transform Infrared Spectrometer (SS-FTIR). Designs for a shadowgraph system for shock wave analysis, design for a micro-particulate collector from ablated pulse were accomplished. A novel spectroscopic system was conceived and a prototype system built for acquisition of spectral/temporal characterization of a high speed event such as from a high explosive detonation. Experiments and analyses will continue into FY16.

  3. Rational design and synthesis of excavated trioctahedral Au nanocrystals

    NASA Astrophysics Data System (ADS)

    Chen, Qiaoli; Jia, Yanyan; Shen, Wei; Xie, Shuifen; Yang, Yanan; Cao, Zhenming; Xie, Zhaoxiong; Zheng, Lansun

    2015-06-01

    Excavated polyhedral nanostructures, possessing the features of high surface area and well-defined surface structure with a specific crystal facet and avoidance of aggregation, could be one of the best choices for the purpose of reducing consumption and improving performance of noble metals in many application fields. However, the formation of the excavated structures is thermodynamically unfavourable and its rational synthesis is far beyond our knowledge. In this work, taking overgrowth of Pd onto trioctahedral Au nanocrystals as a model, we present a deep insight study for synthesizing an excavated structure relying on the protection role of surfactants under suitable crystal growth kinetics. Based on the abovementioned understanding, we designed a simple and effective strategy to synthesize Au nanocrystals with excavated trioctahedral structure in one step. Due to the novel feature of the excavated structure and exposed high energy {110} facets, excavated trioctahedral Au NCs exhibited optical extinction at the near-infrared region and showed high catalytic activity towards the reduction of p-nitrophenol. Moreover, the synthetic strategy can be extended to the synthesis of excavated Au-Pd alloys.Excavated polyhedral nanostructures, possessing the features of high surface area and well-defined surface structure with a specific crystal facet and avoidance of aggregation, could be one of the best choices for the purpose of reducing consumption and improving performance of noble metals in many application fields. However, the formation of the excavated structures is thermodynamically unfavourable and its rational synthesis is far beyond our knowledge. In this work, taking overgrowth of Pd onto trioctahedral Au nanocrystals as a model, we present a deep insight study for synthesizing an excavated structure relying on the protection role of surfactants under suitable crystal growth kinetics. Based on the abovementioned understanding, we designed a simple and effective

  4. Reducing extra-terrestrial excavation forces with percussion

    NASA Astrophysics Data System (ADS)

    Mueller, R.; Smith, J. D.; Lippitt, T.; Schuler, J.; Nick, A.

    High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. A percussive mechanism and 30" wide pivoting bucket were attached to a test stand simulating a basic backhoe with a percussion direction tangent to the direction of movement. Impact energies from 13.6J to 30.5J and frequencies from 0 to 700 beats per minute (BPM) were investigated. A reduction in excavation force of as much as 50% was achieved in this experimental investigation.

  5. Reducing Extra-Terrestrial Excavation Forces with Percussion

    NASA Technical Reports Server (NTRS)

    Mueller, Robert; Schuler, Jason M.; Smith, Jonathan Drew; Nick, Andrew J.; Lippitt, Thomas

    2012-01-01

    High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. A percussive mechanism and 30" wide pivoting bucket were attached at the end of the arm simulating a basic backhoe with a percussion direction tangent to the direction of movement. Impact energies from 13.6J to 30.5J and frequencies from 0 BPM to 700 BPM were investigated. A reduction in excavation force of as much as 50% was achieved in this experimental investigation.

  6. Development of Field Excavator with Embedded Force Measurement

    NASA Technical Reports Server (NTRS)

    Johnson, K.; Creager, C.; Izadnegahdar, A.; Bauman, S.; Gallo, C.; Abel, P.

    2012-01-01

    A semi-intelligent excavation mechanism was developed for use with the NASA-built Centaur 2 rover prototype. The excavator features a continuously rotatable large bucket supported between two parallel arms, both of which share a single pivot axis near the excavator base attached to the rover. The excavator is designed to simulate the collection of regolith, such as on the Moon, and to dump the collected soil into a hopper up to one meter tall for processing to extract oxygen. Because the vehicle can be autonomous and the terrain is generally unknown, there is risk of damaging equipment or using excessive power when attempting to extract soil from dense or rocky terrain. To minimize these risks, it is critical for the rover to sense the digging forces and adjust accordingly. It is also important to understand the digging capabilities and limitations of the excavator. This paper discusses the implementation of multiple strain gages as an embedded force measurement system in the excavator's arms. These strain gages can accurately measure and resolve multi-axial forces on the excavator. In order to validate these sensors and characterize the load capabilities, a series of controlled excavation tests were performed at Glenn Research Center with the excavator at various depths and cut angles while supported by a six axis load cell. The results of these tests are both compared to a force estimation model and used for calibration of the embedded strain gages. In addition, excavation forces generated using two different types of bucket edge (straight vs. with teeth) were compared.

  7. Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.; Lyles, Garry M. (Technical Monitor)

    2001-01-01

    The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p(sub 2)/p(sub 1) approx. 34 and D approx. 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (=6 S/m) behind the detonation wave front. In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T. and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Ohm. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the MHD interaction exerted a

  8. Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2001-01-01

    The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p2/p1 approximately 34 and D approximately 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (approximately = 6 S/m) behind the detonation wave front, In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T, and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Omega. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the NM interaction

  9. Proton radiography of PBX 9502 detonation shock dynamics confinement sandwich test

    SciTech Connect

    Aslam, Tariq D; Jackson, Scott I; Morris, John S

    2009-01-01

    Recent results utilizing proton radiography (P-Rad) during the detonation of the high explosive PBX 9502 are presented. Specifically, the effects of confinement of the detonation are examined in the LANL detonation confinement sandwich geometry. The resulting detonation velocity and detonation shock shape are measured. In addition, proton radiography allows one to image the reflected shocks through the detonation products. Comparisons are made with detonation shock dynamics (DSD) and reactive flow models for the lead detonation shock and detonation velocity. In addition, predictions of reflected shocks are made with the reactive flow models.

  10. Percolation and permeability of fracture networks in Excavated Damaged Zones

    NASA Astrophysics Data System (ADS)

    Mourzenko, V.; Thovert, J.; Adler, P. M.

    2012-12-01

    Generally, the excavation process of a gallery generates fractures in its immediate vicinity. The corresponding zone which is called the Excavated Damaged Zone (EDZ), has a larger permeability than the intact surrounding medium. The properties of the EDZ are attracting more and more attention because of their potential importance in repositories of nuclear wastes. The EDZ which is induced by the excavation process may create along the galleries of the repositories a high permeability zone which could directly connect the storage area with the ground surface. Therefore, the studies of its properties are of crucial importance for applications such as the storage of nuclear wastes. Field observations (such as the ones which have been systematically performed at Mont Terri by [1, 2]) suggest that the fracture density is an exponentially decreasing function of the distance to the wall with a characteristic length of about 0.5 m and that the fracture orientation is anisotropic (most fractures are subparallel to the tunnel walls) and well approximated by a Fisher law whose pole is orthogonal to the wall. Numerical samples are generated according to these prescriptions. Their percolation status and hydraulic transmissivity can be calculated by the numerical codes which are detailed in [3]. Percolation is determined by a pseudo diffusion algorithm. Flow determination necessitates the meshing of the fracture networks and the discretisation of the Darcy equation by a finite volume technique; the resulting linear system is solved by a conjugate gradient algorithm. Only the flow properties of the EDZ along the directions which are parallel to the wall are of interest when a pressure gradient parallel to the wall is applied. The transmissivity T which relates the total flow rate per unit width Q along the wall through the whole EDZ to the pressure gradient grad p, is defined by Q = - T grad p/mu where mu is the fluid viscosity. The percolation status and hydraulic transmissivity

  11. Development of a laser ignited all secondary explosive DDT detonator

    SciTech Connect

    Woods, C.M.; Spangler, E.M.; Beckman, T.M.; Kramer, D.P.

    1992-09-01

    A hermetic, stand alone, laser-ignited deflagration-to-detonation transition (DDT) detonator has been developed. The detonator uses the secondary explosive HMX (cyclotetramethylenetetranitramine) and was originally developed for use with the US Navy`s Laser Initiated Transfer Energy subsystem (LITES). The design of the new detonator allows for its use with a variety of laser fire sets. A high density blend 6f 830 cm2/g HMX with 3% carbon black by weight was used for the ignition charge. Deflagration-to-detonation transition was achieved with a transition charge of undoped 830 cm2/g HMX. Using a 12-ms ND-YAG laser pulse coupled to the detonator via a 1-mm diameter optical fiber, the ignition threshold was determined to be approximately 30 mJ. Full detonating outputs were demonstrated by function testing in Navy detonation sensitivity fittings. Finally, the detonator was tested in several configurations with shielded mild detonating chord (SNMC) endrips to determine its capability for lighting transfer lines.

  12. Numerical simulation of spinning detonation in circular section channels

    NASA Astrophysics Data System (ADS)

    Levin, V. A.; Manuylovich, I. S.; Markov, V. V.

    2016-06-01

    Numerical simulation of three-dimensional structures of gas detonation in circular section channels that emerge due to the instability when the one-dimensional flow is initiated by energy supply at the closed end of the channel is performed. It is found that in channels with a large diameter, an irregular three-dimensional cellular detonation structure is formed. Furthermore, it is found that in channels with a small diameter circular section, the initially plane detonation wave is spontaneously transformed into a spinning detonation wave, while passing through four phases. A critical value of the channel diameter that divides the regimes with the three-dimensional cellular detonation and spinning detonation is determined. The stability of the spinning detonation wave under perturbations occurring when the wave passes into a channel with a greater (a smaller) diameter is investigated. It is found that the spin is preserved if the diameter of the next channel (into which the wave passes) is smaller (respectively, greater) than a certain critical value. The computations were performed on the Lomonosov supercomputer using from 0.1 to 10 billions of computational cells. All the computations of the cellular and spinning detonation were performed in the whole long three-dimensional channel (up to 1 m long) rather than only in its part containing the detonation wave; this made it possible to adequately simulate and investigate the features of the transformation of the detonation structure in the process of its propagation.

  13. Detonation diffraction in combustible high-speed flows

    NASA Astrophysics Data System (ADS)

    Gui, Mingyue; Fan, Baochun; Li, Baoming

    2016-03-01

    Detonation propagating in a T-shaped tube with quiescent and moving hydrogen/oxygen/argon mixtures is numerically examined based on the Euler equations with detailed finite-rate chemistry using the fifth-order weighted essentially non-oscillatory scheme. When diffracted in a quiescent combustible mixture, the detonation wave propagating from the bottom of the T-shaped tube is influenced by the corner rarefaction waves and decays into a non-reacting shock. Subsequently, the decoupled shock reflects irregularly from the top wall. Through several reflections back and forth between the top and bottom walls, a planar detonation is finally re-established. When the combustible mixture in the horizontal part flows from the left to the right, the detonation products ejected from the vertical tube will retard the flow, generating a compression flow upstream and a rarefaction flow downstream. The disturbed detonation on the left side is stronger than that on the right side. The final planar detonation in the upstream direction propagates faster than the Chapman-Jouguet (CJ) detonation with compressed, fine cellular structures, whereas the detonation in the downstream direction propagates more slowly than the CJ detonation with elongated, coarse cellular structures. The details of the transient behavior of diffracting detonation in high-speed flows are discussed.

  14. Simulations of Heterogeneous Detonations and Post Detonation Turbulent Mixing and Afterburning

    NASA Astrophysics Data System (ADS)

    Menon, Suresh; Gottiparthi, Kalyana

    2011-06-01

    Most metal-loaded explosives and thermobaric explosives exploit the afterburning of metals to maintain pressure and temperature conditions.The use of such explosives in complex environment can result in post detonation flow containing many scales of vortical motion, flow jetting and shear, as well as plume-surface interactions due to flow impingement and wall flows. In general, all these interactions can lead to highly turbulent flow fields even if the initial ambient conditions were quiescent. Thus, turbulent mixing can dominate initial mixing and impact the final afterburn. We conduct three-dimensional numerical simulations of the propagation of detonation resulting from metal-loaded (inert or reacting) explosives and analyze the afterburn process as well as the generation of multiple scales of mixing in the post detonation flow field. Impact of the detonation and post-detonation flow field on solid surface is also considered for a variety of initial conditions. Comparison with available data is carried out to demonstrate validity of the simulation method. Supported by Defense Threat Reduction Agency

  15. Deflagration-to-detonation transition by amplification of acoustic waves in type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Charignon, C.; Chièze, J.-P.

    2013-02-01

    Aims: We study a new mechanism for deflagration-to-detonation transition in thermonuclear supernovae (SNe Ia), based on the formation of shocks by amplification of sound waves in the steep density gradients of white dwarfs envelopes. We characterise, in terms of wavelength and amplitude, the perturbations which will ignite a detonation after their amplification. Methods: This study was performed using the well tested HERACLES code, a conservative hydrodynamical code, validated in the present specific application by an analytical description of the propagation of sound waves in white dwarfs. Thermonuclear combustion of the carbon oxygen fuel was treated with the α-chain nuclear reactions network. Results: In planar geometry we found the critical parameter to be the height of shock formation. When it occurs in the inner dense regions (ρ > 106 g cm-3) detonation is inevitable but can take an arbitrarily long time. We found that ignition can be achieved for perturbation as low as Mach number: M ~ 0.005, with heating times compatible with typical explosion time scale (a few seconds). On the opposite no ignition occurs when shocks initiated by small amplitude or large wavelength form further away in less dense regions. We show finally that ignition is also achieved in a spherical self-gravitating spherical model of cold C+O white dwarf of 1.430 M⊙, but due to the spherical damping of sound waves it necessitates stronger perturbation (M ~ 0.02). Small perturbations (M ~ 0.003) could still trigger detonation if a small helium layer is considered. In the context of SNe Ia, one has to consider further the initial expansion of the white dwarf, triggered by the deflagration, prior to the transition to detonation. As the star expands, gradients get flatter and ignition requires increasingly strong perturbations.

  16. From combustion and detonation to nitrogen oxides

    NASA Astrophysics Data System (ADS)

    Ivanov, M. F.; Kiverin, A. D.; Klumov, B. A.; Fortov, V. E.

    2014-03-01

    This paper looks at Ya B Zeldovich's ideas on the combustion and detonation physics of gaseous mixtures and how they evolved as work in this field progressed. The paper demonstrates the fundamental role of Zeldovich's concept of spontaneous combustion waves in studying transient initiation processes for various combustion regimes and in determining the energy and concentration inflammation limits for combustible gaseous mixtures. It shows how his notion that flame front stretching crucially influences flame acceleration in channels explains in a new way the deflagration-to-detonation transition in highly reactive gaseous mixtures. Most of the presented results were obtained by simulations, allowing Zeldovich's ideas to be extended to the combustion of real gaseous mixtures, where chemical reactions and gasdynamical flows add hugely to the complexity of the problem. The paper concludes by using Zeldovich's mechanism to assess the amount of nitrogen oxide produced by a lightning discharge.

  17. Pulse Detonation Engines for High Speed Flight

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2002-01-01

    Revolutionary concepts in propulsion are required in order to achieve high-speed cruise capability in the atmosphere and for low cost reliable systems for earth to orbit missions. One of the advanced concepts under study is the air-breathing pulse detonation engine. Additional work remains in order to establish the role and performance of a PDE in flight applications, either as a stand-alone device or as part of a combined cycle system. In this paper, we shall offer a few remarks on some of these remaining issues, i.e., combined cycle systems, nozzles and exhaust systems and thrust per unit frontal area limitations. Currently, an intensive experimental and numerical effort is underway in order to quantify the propulsion performance characteristics of this device. In this paper, we shall highlight our recent efforts to elucidate the propulsion potential of pulse detonation engines and their possible application to high-speed or hypersonic systems.

  18. Spectrum acquisition of detonation based on CMOS

    NASA Astrophysics Data System (ADS)

    Li, Yan; Bai, Yonglin; Wang, Bo; Liu, Baiyu; Xue, Yingdong; Zhang, Wei; Gou, Yongsheng; Bai, Xiaohong; Qin, Junjun; Xian, Ouyang

    2010-10-01

    The detection of high-speed dynamic spectrum is the main method to acquire transient information. In order to obtain the large amount spectral data in real-time during the process of detonation, a CMOS-based system with high-speed spectrum data acquisition is designed. The hardware platform of the system is based on FPGA, and the unique characteristic of CMOS image sensors in the rolling shutter model is used simultaneously. Using FPGA as the master control chip of the system, not only provides the time sequence for CIS, but also controls the storage and transmission of the spectral data. In the experiment of spectral data acquisition, the acquired information is transmitted to the host computer through the CameraLink bus. The dynamic spectral curve is obtained after the subsequent processing. The experimental results demonstrate that this system is feasible in the acquisition and storage of high-speed dynamic spectrum information during the process of detonation.

  19. Detonation in shocked homogeneous high explosives

    SciTech Connect

    Yoo, C.S.; Holmes, N.C.; Souers, P.C.

    1995-11-01

    We have studied shock-induced changes in homogeneous high explosives including nitromethane, tetranitromethane, and single crystals of pentaerythritol tetranitrate (PETN) by using fast time-resolved emission and Raman spectroscopy at a two-stage light-gas gun. The results reveal three distinct steps during which the homogeneous explosives chemically evolve to final detonation products. These are (1) the initiation of shock compressed high explosives after an induction period, (2) thermal explosion of shock-compressed and/or reacting materials, and (3) a decay to a steady-state representing a transition to the detonation of uncompressed high explosives. Based on a gray-body approximation, we have obtained the CJ temperatures: 3800 K for nitromethane, 2950 K for tetranitromethane, and 4100 K for PETN. We compare the data with various thermochemical equilibrium calculations. In this paper we will also show a preliminary result of single-shot time-resolved Raman spectroscopy applied to shock-compressed nitromethane.

  20. Cable Discharge System for fundamental detonator studies

    NASA Technical Reports Server (NTRS)

    Peevy, Gregg R.; Barnhart, Steven G.; Brigham, William P.

    1994-01-01

    Sandia National Laboratories has recently completed the modification and installation of a cable discharge system (CDS) which will be used to study the physics of exploding bridgewire (EBW) detonators and exploding foil initiators (EFI or slapper). Of primary interest are the burst characteristics of these devices when subjected to the constant current pulse delivered by this system. The burst process involves the heating of the bridge material to a conductive plasma and is essential in describing the electrical properties of the bridgewire foil for use in diagnostics or computer models. The CDS described herein is capable of delivering up to an 8000 A pulse of 3 micron duration. Experiments conducted with the CDS to characterize the EBW and EFI burst behavior are also described. In addition, the CDS simultaneous VISAR capability permits updating the EFI electrical Gurney analysis parameters used in our computer simulation codes. Examples of CDS generated data for a typical EFI and EBW detonator are provided.

  1. Pulse Detonation Rocket Magnetohydrodynamic Power Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.; Jones, J. E.; Dobson, C. C.; Cole, J. W.; Thompson, B. R.; Plemmons, D. H.; Turner, M. W.

    2003-01-01

    The production of onboard electrical power by pulse detonation engines is problematic in that they generate no shaft power; however, pulse detonation driven magnetohydrodynamic (MHD) power generation represents one intriguing possibility for attaining self-sustained engine operation and generating large quantities of burst power for onboard electrical systems. To examine this possibility further, a simple heat-sink apparatus was developed for experimentally investigating pulse detonation driven MHD generator concepts. The hydrogen oxygen fired driver was a 90 cm long stainless steel tube having a 4.5 cm square internal cross section and a short Schelkin spiral near the head end to promote rapid formation of a detonation wave. The tube was intermittently filled to atmospheric pressure and seeded with a CsOH/methanol prior to ignition by electrical spark. The driver exhausted through an aluminum nozzle having an area contraction ratio of A*/A(sub zeta) = 1/10 and an area expansion ratio of A(sub zeta)/A* = 3.2 (as limited by available magnet bore size). The nozzle exhausted through a 24-electrode segmented Faraday channel (30.5 cm active length), which was inserted into a 0.6 T permanent magnet assembly. Initial experiments verified proper drive operation with and without the nozzle attachment, and head end pressure and time resolved thrust measurements were acquired. The exhaust jet from the nozzle was interrogated using a polychromatic microwave interferometer yielding an electron number density on the order of 10(exp 12)/cm at the generator entrance. In this case, MHD power generation experiments suffered from severe near-electrode voltage drops and low MHD interaction; i.e., low flow velocity, due to an inherent physical constraint on expansion with the available magnet. Increased scaling, improved seeding techniques, higher magnetic fields, and higher expansion ratios are expected to greatly improve performance.

  2. Kinetic information from detonation front curvature

    SciTech Connect

    Souers, P. C., LLNL

    1998-06-15

    The time constants for time-dependent modeling may be estimated from reaction zone lengths, which are obtained from two sources One is detonation front curvature, where the edge lag is close to being a direct measure The other is the Size Effect, where the detonation velocity decreases with decreasing radius as energy is lost to the cylinder edge A simple theory that interlocks the two effects is given A differential equation for energy flow in the front is used, the front is described by quadratic and sixth-power radius terms The quadratic curvature comes from a constant power source of energy moving sideways to the walls Near the walls, the this energy rises to the total energy of detonation and produces the sixth-power term The presence of defects acting on a short reaction zone can eliminate the quadratic part while leaving the wall portion of the cuvature A collection of TNT data shows that the reaction zone increases with both the radius and the void fraction

  3. A gasdynamic gun driven by gaseous detonation

    NASA Astrophysics Data System (ADS)

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels.

  4. Some perspectives on pulse detonation propulsion systems

    NASA Astrophysics Data System (ADS)

    Lu, F. K.; Wilson, D. R.

    Pulse detonation engines and rockets (PDE/Rs) can potentially revolutionize air breathing and rocket propulsion [1-6]. While the PDE concept is over five decades old, it has recently enjoyed renewed interest, due mostly to theoretical and computational studies indicating high cycle efficiencies. When modeled by a constant volume, Humphrey cycle, the detonation engine is found to be superior to that of existing constant pressure, Brayton cycles, with claims of as much as 10-40% improvement in specific impulse [4,7-9]. The constant volume process is derived from the Zeldovich-von Neumann-Döring (ZND) model of the detonation wave as a high strength shock wave, followed by a region of chemical reaction and a subsequent isentropic rarefaction. Amongst other advantages of the PDE is simplicity, where the PDE is easy to manufacture and requires few moving parts, with the possibility of eliminating high-pressure pumps in rocket applications, or reducing turbomachinery stages in air-breathing propulsion systems.

  5. A gasdynamic gun driven by gaseous detonation.

    PubMed

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels. PMID:26827358

  6. Plasma Sensor Measurements in Pulse Detonation Engines

    NASA Astrophysics Data System (ADS)

    Matlis, Eric; Marshall, Curtis; Corke, Thomas; Gogineni, Sivaram

    2014-11-01

    Measurements have been conducted in a pulse detonation and rotating detonation engine using a newly developed plasma sensor. This sensor relies on the novel approach of using an ac-driven, weakly-ionized electrical discharge as the main sensing element. The advantages of this approach include a native high bandwidth of 1 MHz without the need for electronic frequency compensation, a dual-mode capability that provides sensitivity to multiple flow parameters, including velocity, pressure, temperature, and gas-species, and a simple and robust design making it very cost effective. The sensor design is installation-compatible with conventional sensors commonly used in gas-turbine research such as the Kulite dynamic pressure sensor while providing much better longevity. Developmental work was performed in high temperature facilities that are relevant to the propulsion and high-speed research community. This includes tests performed in a J85 augmentor at full afterburner and pulse-detonation engines at the University of Cincinnati (UC) at temperatures approaching 2760°C (5000°F).

  7. Characterizing detonator output using dynamic witness plates

    SciTech Connect

    Murphy, Michael John; Adrian, Ronald J

    2009-01-01

    A sub-microsecond, time-resolved micro-particle-image velocimetry (PIV) system is developed to investigate the output of explosive detonators. Detonator output is directed into a transparent solid that serves as a dynamic witness plate and instantaneous shock and material velocities are measured in a two-dimensional plane cutting through the shock wave as it propagates through the solid. For the case of unloaded initiators (e.g. exploding bridge wires, exploding foil initiators, etc.) the witness plate serves as a surrogate for the explosive material that would normally be detonated. The velocity-field measurements quantify the velocity of the shocked material and visualize the geometry of the shocked region. Furthermore, the time-evolution of the velocity-field can be measured at intervals as small as 10 ns using the PIV system. Current experimental results of unloaded exploding bridge wire output in polydimethylsiloxane (PDMS) witness plates demonstrate 20 MHz velocity-field sampling just 300 ns after initiation of the wire.

  8. Multistage reaction pathways in detonating high explosives

    NASA Astrophysics Data System (ADS)

    Li, Ying; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya; CACS Collaboration; ALCF Team

    2015-06-01

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N2 and H2O within 10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct uni-molecular and intermolecular reaction pathways, respectively, for the rapid N2 and H2O productions. This work was supported by the Office of Naval Research Grant No. N000014-12-1-0555 and the Basic Research Program of Defense Threat Reduction Agency (DTRA) Grant No. HDTRA1-08-1-0036. All the simulations were performed at USC and Argonne LCF.

  9. Detonation of Meta-stable Clusters

    SciTech Connect

    Kuhl, Allen; Kuhl, Allen L.; Fried, Laurence E.; Howard, W. Michael; Seizew, Michael R.; Bell, John B.; Beckner, Vincent; Grcar, Joseph F.

    2008-05-31

    We consider the energy accumulation in meta-stable clusters. This energy can be much larger than the typical chemical bond energy (~;;1 ev/atom). For example, polymeric nitrogen can accumulate 4 ev/atom in the N8 (fcc) structure, while helium can accumulate 9 ev/atom in the excited triplet state He2* . They release their energy by cluster fission: N8 -> 4N2 and He2* -> 2He. We study the locus of states in thermodynamic state space for the detonation of such meta-stable clusters. In particular, the equilibrium isentrope, starting at the Chapman-Jouguet state, and expanding down to 1 atmosphere was calculated with the Cheetah code. Large detonation pressures (3 and 16 Mbar), temperatures (12 and 34 kilo-K) and velocities (20 and 43 km/s) are a consequence of the large heats of detonation (6.6 and 50 kilo-cal/g) for nitrogen and helium clusters respectively. If such meta-stable clusters could be synthesized, they offer the potential for large increases in the energy density of materials.

  10. Methods for proving the equivalency of detonator performance

    SciTech Connect

    Munger, Alan C; Akinci, Adrian A; Thomas, Keith A; Clarke, Steve A; Martin, Eric S; Murphy, Michael J

    2009-01-01

    One of the challenges facing engineers is developing newer, safer detonators that are equivalent to devices currently in use. There is no clear consensus on an exact method for drawing equivalence of detonators. This paper summarizes our current efforts to develop diagnostics addressing various aspects of detonator design to better quantify and prove equivalency. We consider various optical techniques to quantify the output pressure and output wave shape. The development of a unique interpretation of streak camera breakouts, known as the apparent center of initiation, will be discussed as a metric for detonation wave shape. Specific examples apply these techniques to the comparison of a new laser-driven detonator with an existing exploding bridgewire (EBW) detonator. Successes and short-comings of the techniques will be discussed.

  11. Numerical simulation of spinning detonation in square tube

    NASA Astrophysics Data System (ADS)

    Tsuboi, Nobuyuki; Asahara, Makoto; Eto, Keitaro; Hayashi, A. Koichi

    2008-09-01

    A single spinning detonation wave propagating in a square tube is simulated three-dimensionally with the detailed chemical reaction mechanism for hydrogen/air mixture proposed by Petersen and Hanson. The spinning detonation is composed of a transverse detonation rotating around the wall normal to the tube axis, triple lines propagating partially out of phase, and a short pressure trail. The formation of an unburned gas pocket behind the detonation front was not observed in the present simulations because the rotating transverse detonation completely consumed the unburned gas. The calculated profiles of instantaneous OH mass fraction have a keystone shape behind the detonation front. The numerical results for the pitch and track angle on the tube wall agree well with the experimental results.

  12. Insensitive detonator apparatus for initiating large failure diameter explosives

    DOEpatents

    Perry, III, William Leroy

    2015-07-28

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  13. Effects of high sound speed confiners on ANFO detonations

    NASA Astrophysics Data System (ADS)

    Kiyanda, Charles; Jackson, Scott; Short, Mark

    2011-06-01

    The interaction between high explosive (HE) detonations and high sound speed confiners, where the confiner sound speed exceeds the HE's detonation speed, has not been thoroughly studied. The subsonic nature of the flow in the confiner allows stress waves to travel ahead of the main detonation front and influence the upstream HE state. The interaction between the detonation wave and the confiner is also no longer a local interaction, so that the confiner thickness now plays a significant role in the detonation dynamics. We report here on larger scale experiments in which a mixture of ammonium nitrate and fuel oil (ANFO) is detonated in aluminium confiners with varying charge diameter and confiner thickness. The results of these large-scale experiments are compared with previous large-scale ANFO experiments in cardboard, as well as smaller-scale aluminium confined ANFO experiments, to characterize the effects of confiner thickness.

  14. Trench Excavated By Viking 1 Surface Sampler

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This image, received today, shows the trench excavated by Viking 1 surface sampler. The trench was dug by extending the surface sampler collection head in a direction from lower right toward the upper left and then withdrawing the surface sampler collector head. Lumpy piles of material at end of trench at lower right was pulled by plowing from trench by the backhoe which will be used to dig trenches later in the mission. Area around trench has ripple marks produced by Martian wind. The trench which was dug early on Sol 8, is about 3 inches wide, 2 inches deep and 6 inches long. Steep dark crater walls show the grains of the Martian surface material stick together (have adhesion). The doming of the surface at far end of the trench show the granular material is dense. The Martian surface material behaves somewhat like moist sand on Earth. Evidence from the trench indicate a sample was collected and delivered to the experiments after repeated tries. The biology experiment level full indicator indicates a sample was received for analysis. The X-Ray fluorescence experiment has no indication to show it received a sample. The GCMS experiment level full indicator suggests no sample was received but this matter is being investigated.

  15. COLLISIONAL EXCAVATION OF ASTEROID (596) SCHEILA

    SciTech Connect

    Bodewits, D.; Kelley, M. S.; Li, J.-Y.; Besse, S.; A'Hearn, M. F.; Landsman, W. B. E-mail: msk@astro.umd.edu E-mail: sbesse@astro.umd.edu E-mail: Wayne.B.Landsman@nasa.gov

    2011-05-20

    We observed asteroid (596) Scheila and its ejecta cloud using the Swift UV-optical telescope. We obtained photometry of the nucleus and the ejecta, and for the first time measured the asteroid's reflection spectrum between 290 and 500 nm. Our measurements indicate significant reddening at UV wavelengths (13% per 10{sup 3} A) and a possible broad, unidentified absorption feature around 380 nm. Our measurements indicate that the outburst has not permanently increased the asteroid's brightness. We did not detect any of the gases that are typically associated with either hypervolatile activity thought responsible for cometary outbursts (CO{sup +}, CO{sub 2} {sup +}), or for any volatiles excavated with the dust (OH, NH, CN, C{sub 2}, C{sub 3}). We estimate that 6 x 10{sup 8} kg of dust was released with a high ejection velocity of 57 m s{sup -1} (assuming 1 {mu}m sized particles). While the asteroid is red in color and the ejecta have the same color as the Sun, we suggest that the dust does not contain any ice. Based on our observations, we conclude that (596) Scheila was most likely impacted by another main belt asteroid less than 100 m in diameter.

  16. Dynamics of detonations and explosions: Detonations; International Colloquium on Dynamics of Explosions and Reactive Systems, 12th, University of Michigan, Ann Arbor, July 23-28, 1989, Technical Papers

    SciTech Connect

    Kuhl, A.L.; Leyer, J.-C.; Borisov, A.A.; Sirignano, W.A.

    1991-01-01

    The present volume on the dynamics of gaseous detonations, detonation initiation and transmission, multiphase detonations, and nonideal detonations and boundary effects, discusses the detonability of hydrocarbon fuels in air, the detonation of cryogenic gaseous hydrogen-oxygen mixtures, chemical kinetics-detonation structure correlations for gaseous explosives, the initiation of hydrogen-air detonations by turbulent fluorine-air jets, and the initiation of a detonation wave due to multistage self-ignition. Also discussed are the limit criterion for detonation in circular cubes, oblique detonation at hypersonic velocities, the mechanisms of detonation propagation in porous structures, surface detonations and indirect ignition processes, the detonation of unconfined large-scale fuel-spray/air clouds, the detonation structure of corn starch particles-oxygen mixtures, and the lean detonation limit of sensitized kerosene sprays in air.

  17. Explosives malfunction from sympathetic detonation to shock desensitization

    SciTech Connect

    Katsabanis, P.D.; Yeung, C.; Fitz, G.; Heater, R.

    1994-12-31

    Explosives malfunction due to shock waves is a serious concern for successful blasting results. Malfunction can range from sympathetic detonation to desensitization and modification of firing times of conventional pyrotechnic detonators. Decked charges consisting of commercial emulsion explosives having a detonator and a primer were placed in 10cm diameter blastholes and their performance was recorded. Due to the limited length of the holes the events were mainly sympathetic detonations although desensitization was also recorded. Pressure measurements along the stemming column showed that shock waves produced by an explosive have a significant amplitude even at relatively large distances away from the detonating explosive. It was found that 2m away from a detonating charge the pressures in the stemming material were above 0.1 GPa indicating that there is potential for primers and detonators to malfunction. Parallel charges consisting of a commercial emulsion explosive with a diameter of 32mm were confined in 2mm thick steel tubes and initiation was attempted using detonators having a delay interval of 25ms. The charges were placed in sand and the velocity of detonation of the acceptor charge was recorded using a continuous resistance probe system. Carbon resistors were also placed in the same position as the acceptor charge to examine the dynamic pressures that were applied to the charge. Sympathetic detonation, complete desensitization, partial desensitization and properly sequenced detonations were observed as the distance between charges was increased from 76 mm to 305 mm. Delay detonators were also tested in a similar to the last configuration. Modification of firing times was observed at distances between 150 and 360 mm.

  18. Future Modeling Needs in Pulse Detonation Rocket Engine Design

    NASA Technical Reports Server (NTRS)

    Meade, Brian; Talley, Doug; Mueller, Donn; Tew, Dave; Guidos, Mike; Seymour, Dave

    2001-01-01

    This paper presents a performance model rocket engine design that takes advantage of pulse detonation to generate thrust. The contents include: 1) Introduction to the Pulse Detonation Rocket Engine (PDRE); 2) PDRE modeling issues and options; 3) Discussion of the PDRE Performance Workshop held at Marshall Space Flight Center; and 4) Identify needs involving an open performance model for Pulse Detonation Rocket Engines. This paper is in viewgraph form.

  19. Determination of near field excavation disturbance in crystalline rock

    SciTech Connect

    Koopmans, R.; Hughes, R.W.

    1986-01-01

    The computerized dilatometer system has rapidly and economically provided deformation moduli of low and high modulus rock, determined the extent of excavation disturbance surrounding an underground opening and located open fracture within a rock mass. Results from both test sites indicate that the moduli obtained were influenced by the in situ tangential stress field. It has been shown that the near field excavation disturbance is kept to a minimum through the use of careful excavation techniques such as the tunnel boring machine. In turn, the in situ tangential stress levels and deformation moduli are maximized while the corresponding permeability is minimized.

  20. Reducing Extra-Terrestrial Excavation Forces with Percussion

    NASA Technical Reports Server (NTRS)

    Schuler, Jason; Mueller, Robert; Smith, Drew; Nick, Andrew; Lippitt, Thomas

    2012-01-01

    High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. The goal of percussive excavation is to fluidize dry regolith in front of the leading edge of the tool by mechanically separating the microscopic interlocking grains resulting in a reduced force needed to shear the soil. There are several variables involved with this technique; this experiment varied: Impact energy, frequency, and excavation speed and held constant: impact direction, depth of cut, angle of tool, and soil bulk density. The test apparatus consisted of an aluminum truss bridge with a central pivoting arm. Attached to the arm was a winch with a load cell in line that recorded the tension in the cable and therefore the excavation load. The arm could be adjusted for excavation depth which was recorded along with the arm angle relative to the bridge. A percussive mechanism and 30" wide pivoting bucket were attached at the end of the arm simulating a basic backhoe with a percussion direction tangent to the direction of . movement. Internally the mechanism used a set of die springs and barrel cam to produce the percussive blow. By changing the springs and the speed of the motor the impact energy and frequency of percussion could be varied independently. Impact energies from 11.2J to 30.5J and frequencies from 0 BPM to 700 BPM were investigated. A reduction in excavation force of as much as 51% was achieved in this experimental investigation. Smaller percussive digging implements, tested by others, have achieved a

  1. Changes in rock salt permeability due to nearby excavation

    SciTech Connect

    Stormont, J C; Howard, C L

    1991-07-01

    Changes in brine and gas permeability of rock salt as a result of nearby excavation (mine-by) have been measured from the underground workings of the WIPP facility. Prior to the mine-by, the formation responds as a porous medium with a very low brine permeability, a significant pore (brine) pressure and no measurable gas permeability. The mine-by excavation creates a dilated, partially saturated zone in the immediate vicinity of the excavation with an increased permeability to brine and a measurable permeability to gas. The changes in hydrologic properties are discussed in the context of pore structure changes.

  2. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q.; Fisher, R. T.; Townsley, D. M.; Meakin, C.; Reid, L. B.

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  3. Effects of diameter and temperature on XTX-8004 detonation velocity

    SciTech Connect

    Campos, C.A.

    1980-10-01

    This study was performed to determine the dependence of XTX-8004 steady detonation velocity on charge diameter and temperature. The tests were performed for four different diameters at three temperatures using a standard 4-track detonation velocity block and corresponding printed circuit ionization switch plate. The explosive was loaded in the detonation velocity block to a nominal density of 1.553 g/cc. Measurements obtained from two samples per temperature indicate the critical diameter is less than 0.178 cm. A relationship between detonation velocity and density due to temperature was established using experimental measurements.

  4. Detonation shock dynamics calibration for non-ideal HE: ANFO

    SciTech Connect

    Short, Mark; Salyer, Terry R; Aslam, Tariq D; Kiyanda, Charles B; Morris, John S; Zimmerley, Tony

    2009-01-01

    Linear D{sub n}-{kappa} detonation shock dynamics (DSD) filling forms are obtained for four ammonium nitrate-fuel oil (ANFO) mixtures involving variations in the ammonium nitrate prill properties and ANFO stoichiometries. The detonation of ammonium nitrate-fuel oil (ANFO) mixtures is considered to be highly nonideal involving long reaction zones ({approx} several cms), low detonation energies and large failure diameters ({approx} 10s-100s cms). A number of experimental programs have been undertaken to understand ANFO detonation properties as a function of the AN properties [1]-[7]. Given the highly heterogeneous nature of ANFO mixtures (typical high explosive (HE) grade AN prills are porous with a range of diameters) a predictive reactive flow simulation of ANFO detonation will present significant challenges. At Los Alamos, a simulation capability has been developed for predicting the propagation of detonation in non-ideal HE and the work conducted on surrounding materials via a combination of a detonation shock dynamics (DSD) approach and a modified programmed burn method known as the pseudo-reaction-zone (or PRZ) method that accounts for the long detonation reaction zone. In the following, linear D{sub n}-{kappa} DSD fitting forms are obtained for four ammonium nitrate-fuel oil mixtures involving variation in the ammonium nitrate prill properties and ANFO stoichiometries. A detonation shock dynamics calibration for ANFO consisting of regular porous HE grade AN in a 94/6 wt.% AN to FO mix has been obtained in [7].

  5. Safety and performance enhancement circuit for primary explosive detonators

    DOEpatents

    Davis, Ronald W.

    2006-04-04

    A safety and performance enhancement arrangement for primary explosive detonators. This arrangement involves a circuit containing an energy storage capacitor and preset self-trigger to protect the primary explosive detonator from electrostatic discharge (ESD). The circuit does not discharge into the detonator until a sufficient level of charge is acquired on the capacitor. The circuit parameters are designed so that normal ESD environments cannot charge the protection circuit to a level to achieve discharge. When functioned, the performance of the detonator is also improved because of the close coupling of the stored energy.

  6. A library of prompt detonation reaction zone data

    SciTech Connect

    Souers, P. C., LLNL

    1998-06-01

    Tables are given listing literature data that allows calculation of sonic reaction zones at or near steady-state for promptly detonating explosive cylinders. The data covers homogeneous, heterogeneous, composite, inorganic and binary explosives and allows comparison across the entire explosive field. Table 1 lists detonation front curvatures. Table 2 lists Size Effect data, i.e. the change of detonation velocity with cylinder radius. Table 3 lists failure radii and detonation velocities. Table 4 lists explosive compositions. A total of 51 references dating back into the 1950`s are given. Calculated reaction zones, radii of curvature and growth rate coefficients are listed.

  7. Hydroxyapatite Reinforced Coatings with Incorporated Detonationally Generated Nanodiamonds

    SciTech Connect

    Pramatarova, L.; Pecheva, E.; Hikov, T.; Fingarova, D.; Dimitrova, R.; Spassov, T.; Krasteva, N.; Mitev, D.

    2010-01-21

    We studied the effect of the substrate chemistry on the morphology of hydroxyapatite-detonational nanodiamond composite coatings grown by a biomimetic approach (immersion in a supersaturated simulated body fluid). When detonational nanodiamond particles were added to the solution, the morphology of the grown for 2 h composite particles was porous but more compact then that of pure hydroxyapatite particles. The nanodiamond particles stimulated the hydroxyapatite growth with different morphology on the various substrates (Ti, Ti alloys, glasses, Si, opal). Biocompatibility assay with MG63 osteoblast cells revealed that the detonational nanodiamond water suspension with low and average concentration of the detonational nanodiamond powder is not toxic to living cells.

  8. Hydroxyapatite Reinforced Coatings with Incorporated Detonationally Generated Nanodiamonds

    NASA Astrophysics Data System (ADS)

    Pramatarova, L.; Pecheva, E.; Dimitrova, R.; Spassov, T.; Krasteva, N.; Hikov, T.; Fingarova, D.; Mitev, D.

    2010-01-01

    We studied the effect of the substrate chemistry on the morphology of hydroxyapatite-detonational nanodiamond composite coatings grown by a biomimetic approach (immersion in a supersaturated simulated body fluid). When detonational nanodiamond particles were added to the solution, the morphology of the grown for 2 h composite particles was porous but more compact then that of pure hydroxyapatite particles. The nanodiamond particles stimulated the hydroxyapatite growth with different morphology on the various substrates (Ti, Ti alloys, glasses, Si, opal). Biocompatibility assay with MG63 osteoblast cells revealed that the detonational nanodiamond water suspension with low and average concentration of the detonational nanodiamond powder is not toxic to living cells.

  9. Detonation Shock Dynamics Calibration for Non-Ideal HE: ANFO

    NASA Astrophysics Data System (ADS)

    Short, Mark; Salyer, Terry

    2009-06-01

    The detonation of ammonium nitrate (AN) and fuel-oil (FO) mixtures (ANFO) is significantly influenced by the properties of the AN (porosity, particle size, coating) and fuel-oil stoichiometry. We report on a new series of rate-stick experiments in cardboard confinement that highlight detonation front speed and curvature dependence on AN/FO stoichiometry and AN particle properties. Standard detonation velocity-curvature calibrations to the experimental data will be presented, as well as higher-order time-dependent detonation shock dynamics calibrations.

  10. Molecular-dynamics investigation of the desensitization of detonable material

    NASA Astrophysics Data System (ADS)

    Rice, Betsy M.; Mattson, William; Trevino, Samuel F.

    1998-05-01

    A molecular-dynamics investigation of the effects of a diluent on the detonation of a model crystalline explosive is presented. The diluent, a heavy material that cannot exothermally react with any species of the system, is inserted into the crystalline explosive in two ways. The first series of simulations investigates the attenuation of the energy of a detonation wave in a pure explosive after it encounters a small layer of crystalline diluent that has been inserted into the lattice of the pure explosive. After the shock wave has traversed the diluent layer, it reenters the pure explosive. Unsupported detonation is not reestablished unless the energy of the detonation wave exceeds a threshold value. The second series of simulations investigates detonation of solid solutions of different concentrations of the explosive and diluent. For both types of simulations, the key to reestablishing or reaching unsupported detonation is the attainment of a critical number density behind the shock front. Once this critical density is reached, the explosive molecules make a transition to an atomic phase. This is the first step in the reaction mechanism that leads to the heat release that sustains the detonation. The reactive fragments formed from the atomization of the heteronuclear reactants subsequently combine with new partners, with homonuclear product formation exothermally favored. The results of detonation of the explosive-diluent crystals are consistent with those presented in an earlier study on detonation of pure explosive [B. M. Rice, W. Mattson, J. Grosh, and S. F. Trevino, Phys. Rev. E 53, 611 (1996)].

  11. Type Ia Supernovae: Can Coriolis Force Break the Symmetry of the Gravitational Confined Detonation Explosion Mechanism?

    NASA Astrophysics Data System (ADS)

    García-Senz, D.; Cabezón, R. M.; Domínguez, I.; Thielemann, F. K.

    2016-03-01

    Currently the number of models aimed at explaining the phenomena of type Ia supernovae is high and distinguishing between them is a must. In this work we explore the influence of rotation on the evolution of the nuclear flame that drives the explosion in the so-called gravitational confined detonation models. Assuming that the flame starts in a pointlike region slightly above the center of the white dwarf (WD) and adding a moderate amount of angular velocity to the star we follow the evolution of the deflagration using a smoothed particle hydrodynamics code. We find that the results are very dependent on the angle between the rotational axis and the line connecting the initial bubble of burned material with the center of the WD at the moment of ignition. The impact of rotation is larger for angles close to 90° because the Coriolis force on a floating element of fluid is maximum and its principal effect is to break the symmetry of the deflagration. Such symmetry breaking weakens the convergence of the nuclear flame at the antipodes of the initial ignition volume, changing the environmental conditions around the convergence region with respect to non-rotating models. These changes seem to disfavor the emergence of a detonation in the compressed volume at the antipodes and may compromise the viability of the so-called gravitational confined detonation mechanism.

  12. The influence of detonation cell size and regularity on the propagation of gaseous detonations in granular materials

    NASA Astrophysics Data System (ADS)

    Slungaard, T.; Engebretsen, T.; Sønju, O. K.

    This paper presents results from an experimental study of transmission of gaseous detonation waves through various granular filters. Spherical glass beads of 4 and 8 mm diameter and crushed rock of 7.5 mm volume averaged diameter were used as filter material. Varying the initial pressure of the detonating gas mixture controlled the detonation cell size. Dilution with argon was used to vary the detonation cell regularity. The complete range from almost no detonation velocity deficit to complete extinction of the combustion wave was observed. The existing correlation for gaseous detonation velocity deficit V/VCJ = [1-0.35 (d_ c/dps)] +/- 0.1 where dc is the critical diameter for the gaseous detonation and dps is the pore size, is found to be applicable for both smooth spherical particles and irregular crushed rock when considering irregular detonation structures. Soot films and pressure measurements show that as the detonation cell size is increased, reinitiation of a reanular filter until it finally no longer occurs at V/VCJ ~ 0.4--0.45. Complete extinction of the combustion wave occurs at V/VCJ ~ 0.25--0.3. These two limits appear to be about the same for irregular and regular detonation cell structures. For irregular structures without argon dilution, dc/dps ~ 50 can be found for detonation wave failure, and dc/dps ~ 100 can be found for complete extinction of the combustion wave. For argon dilution these limits are changed to dc/dps ~ 10 and dc/dps ~ 40, respectively. The data are a bit scarce as a basis for proposing a new correlation for regular structures, but as a first approximation V/VCJ =[0.8--0.35log(dc/dps)] +/- 0.1 is suggested for regular structures. The detonation or combustion wave is found to approach a constant velocity in the granular filter if not extinguished.

  13. Blasting and excavating on precarious rock slopes

    SciTech Connect

    Oriard, L.L.

    1996-12-01

    There is an intuitive tendency to equate rock strength with rock stability, yet the two must be evaluated separately. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. The time element is a matter of special concern, that is how suddenly the failure begins and how rapidly it progresses. An important element in avoiding catastrophes is to study the site geology for dangerous conditions, implement the types of blasting procedures that minimize failures, and evaluate the potential use of reinforcement or other mechanical stabilizing procedures. It may be possible to reinforce the perimeters of structural excavations, but that is not usually possible for quarry or surface mine operations. However, it is often possible to change a dangerous operation into a safe one merely by changing the orientation, sequence or dimensions of the work without changing other details of the blasting designs. Several important principles are illustrated in this paper, using case histories. One case is that of a catastrophic slope failure in Mexico, and the remedial procedures used to get the work back into operation. That case is compared to large-scale work which was done safely on a similar site in Spain, even with an 850 ft high slope and up to 200 ft between safety benches. Also illustrated are some of the procedures used for delicate work on sensitive slopes at a site in Colombia, South America, and those used to preserve a delicate narrow rib of rock in a deep river canyon on the Snake River in Idaho. Brief reference is made also to slope damage on a Canadian project.

  14. Hollow Cylinder Tests on Boom Clay: Modelling of Strain Localization in the Anisotropic Excavation Damaged Zone

    NASA Astrophysics Data System (ADS)

    François, Bertrand; Labiouse, Vincent; Dizier, Arnaud; Marinelli, Ferdinando; Charlier, Robert; Collin, Frédéric

    2014-01-01

    Boom Clay is extensively studied as a potential candidate to host underground nuclear waste disposal in Belgium. To guarantee the safety of such a disposal, the mechanical behaviour of the clay during gallery excavation must be properly predicted. In that purpose, a hollow cylinder experiment on Boom Clay has been designed to reproduce, in a small-scale test, the Excavation Damaged Zone (EDZ) as experienced during the excavation of a disposal gallery in the underground. In this article, the focus is made on the hydro-mechanical constitutive interpretation of the displacement (experimentally obtained by medium resolution X-ray tomography scanning). The coupled hydro-mechanical response of Boom Clay in this experiment is addressed through finite element computations with a constitutive model including strain hardening/softening, elastic and plastic cross-anisotropy and a regularization method for the modelling of strain localization processes. The obtained results evidence the directional dependency of the mechanical response of the clay. The softening behaviour induces transient strain localization processes, addressed through a hydro-mechanical second grade model. The shape of the obtained damaged zone is clearly affected by the anisotropy of the materials, evidencing an eye-shaped EDZ. The modelling results agree with experiments not only qualitatively (in terms of the shape of the induced damaged zone), but also quantitatively (for the obtained displacement in three particular radial directions).

  15. 4. VIEW OF AREA EXCAVATED FOR ACCESS TO MERCURY RETORT. ...

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

    4. VIEW OF AREA EXCAVATED FOR ACCESS TO MERCURY RETORT. VIEW SOUTH FROM RETORT. (OCTOBER, 1995) - McCormick Group Mine, Mercury Retort, East slope of Buckskin Mountain, Paradise Valley, Humboldt County, NV

  16. CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING ...

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

    CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING (CPP-601) LOOKING SOUTH. INL PHOTO NUMBER NRTS-50-693. Unknown Photographer, 1950 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

  17. EXCAVATION OF EAST (FRONT) BASEMENT WELL AND DRAINAGE SYSTEM, WITH ...

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

    EXCAVATION OF EAST (FRONT) BASEMENT WELL AND DRAINAGE SYSTEM, WITH ARCHED ENTRY INTO BASEMENT UNDER FRONT ENTRY IN BACKGROUND, LOOKING NORTH (NOTE GALLETING IN BRICK FOUNDATION) - Belair, Tulip Grove Drive, Belair-at-Bowie, Bowie, Prince George's County, MD

  18. General view of the archaeological site showing excavation and revealing ...

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

    General view of the archaeological site showing excavation and revealing the steps leading down into the eighteenth-century burial vault - Harry Buck House, North of Main Street (14800 Governor Oden Bowie Drive), Upper Marlboro, Prince George's County, MD

  19. 48. EXCAVATING AND DRIVING PILES FOR SHOOFLY BRIDGE, YOLO COUNTY ...

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

    48. EXCAVATING AND DRIVING PILES FOR SHOOFLY BRIDGE, YOLO COUNTY SIDE OF RIVER, November 7, 1934 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

  20. 13. AERIAL VIEW SHOWING IN THE FOREGROUND, EXCAVATION FOR THE ...

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

    13. AERIAL VIEW SHOWING IN THE FOREGROUND, EXCAVATION FOR THE SPILLWAY APRON.... Volume XVII, No. 12, December 26, 1939. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  1. 14. FLOODED POWER HOUSE FOUNDATION EXCAVATION BEING PUMPED OUT. NOTE ...

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

    14. FLOODED POWER HOUSE FOUNDATION EXCAVATION BEING PUMPED OUT. NOTE KEYS IN FOREBAY ABUTMENT TO INTERLOCK WITH POWER HOUSE FOUNDATION, March 1918. - Dam No. 5 Hydroelectric Plant, On Potomac River, Hedgesville, Berkeley County, WV

  2. 9. View looking S at archeological excavations at base of ...

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

    9. View looking S at archeological excavations at base of wall adjacent to Jamaican Train. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR

  3. 1. AERIAL VIEW SHOWING ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN ...

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

    1. AERIAL VIEW SHOWING ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN FORMER ERECTING SHOP. MACHINE SHOP IS BUILDING AT RIGHT. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  4. 2. CLOSE IN AERIAL VIEW OF ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE ...

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

    2. CLOSE IN AERIAL VIEW OF ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN FORMER ERECTING SHOP. MACHINE SHOP IS BUILDING AT RIGHT. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  5. 8. General view looking S at archeological excavations along base ...

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

    8. General view looking S at archeological excavations along base of west wall of purging house. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR

  6. 18. View of archeological excavations along base of mill wall ...

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

    18. View of archeological excavations along base of mill wall showing unidentified pits. - Hacienda Azucarera La Esperanza, Mill (Ruins), 2.65 miles North of PR Route 2 Bridge Over Manati River, Manati, Manati Municipio, PR

  7. 9. Excavation work at Pleasant Dam (now called Waddell Dam). ...

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

    9. Excavation work at Pleasant Dam (now called Waddell Dam). Photographer unknown, July, 22, 1926. Source: Maricopa County Municipal Water Conservation District Number One (MWD). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  8. 27. photographer unknown undated DREDGING OVERBURDEN FROM CRIB EXCAVATION AREAS ...

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

    27. photographer unknown undated DREDGING OVERBURDEN FROM CRIB EXCAVATION AREAS IN MAIN CHANNEL FOR FIRST STEP COFFERDAM. BRADFORD ISLAND IN BACKGROUND. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  9. 42. View of emergency spillway excavation looking downstream from spillway. ...

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

    42. View of emergency spillway excavation looking downstream from spillway. Photographer unknown, 1929. Source: ADWR. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  10. 41. Upstream end of emergency spillway excavation. Photographer unknown, 1929. ...

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

    41. Upstream end of emergency spillway excavation. Photographer unknown, 1929. Source: Arizona Department of Water Resources (ADWR). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  11. 16. TAILRACE ARCH FROM 1814 MILL BROKEN THROUGH DURING EXCAVATION ...

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

    16. TAILRACE ARCH FROM 1814 MILL BROKEN THROUGH DURING EXCAVATION FOR A SURFACE WATER RUNOFF POLLUTION TRAP, SUBSEQUENTLY FILLED. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA

  12. Telerobotic Excavator Designed to Compete in NASA's Lunabotics Mining Competition

    NASA Technical Reports Server (NTRS)

    Nash, Rodney; Santin, Cara; Yousef, Ahmed; Nguyen, Thien; Helferty, John; Pillapakkam, Shriram

    2011-01-01

    The second annual NASA Lunabotics Mining competition is to be held in May 23-28, 2011. The goal of the competition is for teams of university level students to design, build, test and compete with a fully integrated lunar excavator on a simulated lunar surface. Our team, named Lunar Solutions I, will be representing Temple University's College of Engineering in the competition. The team's main goal was to build a robot which is able to compete with other teams, and ultimately win the competition. The main challenge of the competition was to build a wireless robot that can excavate and collect a minimum of 10 kilograms of the regolith material within 15 minutes. The robot must also be designed to operate in conditions similar to those found on the lunar surface. The design of the lunar excavator is constrained by a set of requirements determined by NASA and detailed in the competition's rulebook. The excavator must have the ability to communicate with the "main base" wirelessly, and over a Wi-Fi network. Human operators are located at a remote site approximately 60 meters away from the simulated lunar surface upon which the robot must excavate the lunar regolith surface. During the competition, the robot will operate in a separate area from the control room in an area referred to as the "Lunarena." From the control room, the operators will have to control the robot using visual feedback from cameras placed both within the arena and on the robot. Using this visual feedback the human operators control the robots movement using both keyboard and joystick commands. In order to place in the competition, a minimum of 10 kg of regolith material has to be excavated, collected, and dumped into a specific location. For that reason, the robot must be provided with an effective and powerful excavation system. Our excavator uses tracks for the drive system. After performing extensive research and trade studies, we concluded that tracks would be the most effective method for

  13. Impact-Actuated Digging Tool for Lunar Excavation

    NASA Technical Reports Server (NTRS)

    Wilson, Jak; Chu, Philip; Craft, Jack; Zacny, Kris; Santoro, Chris

    2013-01-01

    NASA s plans for a lunar outpost require extensive excavation. The Lunar Surface Systems Project Office projects that thousands of tons of lunar soil will need to be moved. Conventional excavators dig through soil by brute force, and depend upon their substantial weight to react to the forces generated. This approach will not be feasible on the Moon for two reasons: (1) gravity is 1/6th that on Earth, which means that a kg on the Moon will supply 1/6 the down force that it does on Earth, and (2) transportation costs (at the time of this reporting) of $50K to $100K per kg make massive excavators economically unattractive. A percussive excavation system was developed for use in vacuum or nearvacuum environments. It reduces the down force needed for excavation by an order of magnitude by using percussion to assist in soil penetration and digging. The novelty of this excavator is that it incorporates a percussive mechanism suited to sustained operation in a vacuum environment. A percussive digger breadboard was designed, built, and successfully tested under both ambient and vacuum conditions. The breadboard was run in vacuum to more than 2..times the lifetime of the Apollo Lunar Surface Drill, throughout which the mechanism performed and held up well. The percussive digger was demonstrated to reduce the force necessary for digging in lunar soil simulant by an order of magnitude, providing reductions as high as 45:1. This is an enabling technology for lunar site preparation and ISRU (In Situ Resource Utilization) mining activities. At transportation costs of $50K to $100K per kg, reducing digging forces by an order of magnitude translates into billions of dollars saved by not launching heavier systems to accomplish excavation tasks necessary to the establishment of a lunar outpost. Applications on the lunar surface include excavation for habitats, construction of roads, landing pads, berms, foundations, habitat shielding, and ISRU.

  14. NOVEL EXCAVATION TECHNOLOGIES FOR EFFICIENT AND ECONOMIC SURFACE MINING

    SciTech Connect

    Vladislav Kecojevic; Samuel Frimpong

    2005-05-01

    Ground excavation constitutes a significant component of production costs in any surface mining operation. The excavation process entails material digging and removal in which the equipment motion is constrained by the workspace geometry. A major excavation problem is the variability of material properties, resulting in varying mechanical energy input and stress loading of shovel dipper-and-tooth assembly across the working bench. This variability has a huge impact on the shovel dipper and tooth assembly in hard formations. With this in mind, the primary objectives of the project were to (i) provide the theoretical basis to develop the Intelligent Shovel Excavation (ISE) technology to solve the problems associated with excavation in material formations; (ii) advance knowledge and frontiers in shovel excavation through intelligent navigation; and (iii) submit proposal for the design, development and implementation of the ISE technology for shovel excavation at experimental surface mining sites. The mathematical methods were used to (i) develop shovel's kinematics and dynamics, and (ii) establish the relationship between shovel parameters and the resistive forces from the material formation during excavation process. The ADAMS simulation environment was used to develop the hydraulic and cable shovel virtual prototypes. Two numerical examples are included to test the theoretical hypotheses and the obtained results are discussed. The area of sensor technology was studied. Application of specific wrist-mounted sensors to characterize the material, bucket and frame assembly was determined. Data acquisition, display and control system for shovel loading technology was adopted. The concept of data acquisition and control system was designed and a shovel boom stresses were simulated. A multi-partner collaboration between research organizations, shovel manufacturer, hardware and sensor technology companies, and surface mining companies is proposed to test design features

  15. Intelligent excavator control system for lunar mining system

    NASA Astrophysics Data System (ADS)

    Lever, Paul J. A.; Wang, Fei-Yue

    1995-01-01

    A major benefit of utilizing local planetary resources is that it reduces the need and cost of lifting materials from the Earth's surface into Earth orbit. The location of the moon makes it an ideal site for harvesting the materials needed to assist space activities. Here, lunar excavation will take place in the dynamic unstructured lunar environment, in which conditions are highly variable and unpredictable. Autonomous mining (excavation) machines are necessary to remove human operators from this hazardous environment. This machine must use a control system structure that can identify, plan, sense, and control real-time dynamic machine movements in the lunar environment. The solution is a vision-based hierarchical control structure. However, excavation tasks require force/torque sensor feedback to control the excavation tool after it has penetrated the surface. A fuzzy logic controller (FLC) is used to interpret the forces and torques gathered from a bucket mounted force/torque sensor during excavation. Experimental results from several excavation tests using the FLC are presented here. These results represent the first step toward an integrated sensing and control system for a lunar mining system.

  16. The delayed-detonation model of Type Ia supernovae. 2: The detonation phase

    NASA Technical Reports Server (NTRS)

    Arnett, David; Livne, Eli

    1994-01-01

    The investigation, by use of two-dimensional numerical hydrodynamics simulations, of the 'delayed detonation' mechanism of Khokhlov for the explosion of Type Ia supernovae is continued. Previously we found that the deflagration is insufficient to unbind the star. Expansion shuts off the flame; much of this small production of iron group nuclei occurs at lower densities, which reduces the electron-capture problem. Because the degenerate star has an adiabatic exponent only slightly above 4/3, the energy released by deflagration drives a pulsation of large amplitude. During the first expansion phase, adiabatic cooling shuts off the burning, and a Rayleigh-Taylor instability then gives mixing of high-entropy ashes with low-entropy fuel. During the first contraction phase, compressional heating reignites the material. The burning was allowed to develop into a detonation in these nonspherical models. The detonation grows toward spherical symmetry at late times. At these densities (rho approx. 10(exp 7) to 10(exp 8) g cm(exp -3)), either Ni-56 or nuclei of the Si-Ca group are the dominant products of the burning. The bulk yields are sensitive to the density of the star when the transition to detonation occurs. The relevance of the abundances, velocities, mixing, and total energy release to the theory and interpretation of Type Ia supernovae is discussed.

  17. A flash vaporization system for detonation of hydrocarbon fuels in a pulse detonation engine

    NASA Astrophysics Data System (ADS)

    Tucker, Kelly Colin

    Current research by both the US Air Force and Navy is concentrating on obtaining detonations in a pulse detonation engine (PDE) with low vapor pressure, kerosene based jet fuels. These fuels, however, have a low vapor pressure and the performance of a liquid hydrocarbon fueled PDE is significantly hindered by the presence of fuel droplets. A high pressure, fuel flash vaporization system (FVS) has been designed and built to reduce and eliminate the time required to evaporate the fuel droplets. Four fuels are tested: n-heptane, isooctane, aviation gasoline, and JP-8. The fuels vary in volatility and octane number and present a clear picture on the benefits of flash vaporization. Results show the FVS quickly provided a detonable mixture for all of the fuels tested without coking or clogging the fuel lines. Combustion results validated the model used to predict the fuel and air temperatures required to achieve gaseous mixtures with each fuel. The most significant achievement of the research was the detonation of flash vaporized JP-8 and air. The results show that the flash vaporized JP-8 used 20 percent less fuel to ignite the fuel air mixture twice as fast (8 ms from 16 ms) when compared to the unheated JP-8 combustion data. Likewise, the FVS has been validated as a reliable method to create the droplet free mixtures required for liquid hydrocarbon fueled PDEs.

  18. Geohydromechanical Processes in the Excavation Damaged Zone in Crystalline Rock, Rock Salt, and Indurated and Plastic Clays

    SciTech Connect

    Tsang, Chin-Fu; Bernier, Frederic; Davies, Christophe

    2004-06-20

    The creation of an excavation disturbed zone or excavation damaged zone is expected around all man-made openings in geologic formations. Macro- and micro-fracturing, and in general a redistribution of in situ stresses and rearrangement of rock structures, will occur in this zone, resulting in drastic changes of permeability to flow, mainly through the fractures and cracks induced by excavation. Such an EDZ may have significant implications for the operation and long-term performance of an underground nuclear waste repository. Various issues of concern need to be evaluated, such as processes creating fractures in the excavation damaged zone, the degree of permeability increase, and the potential for sealing or healing (with permeability reduction) in the zone. In recent years, efforts along these lines have been made for a potential repository in four rock types-crystalline rock, salt, indurated clay, and plastic clay-and these efforts have involved field, laboratory, and theoretical studies. The present work involves a synthesis of the ideas and issues that emerged from presentations and discussions on EDZ in these four rock types at a CLUSTER Conference and Workshop held in Luxembourg in November, 2003. First, definitions of excavation disturbed and excavation damaged zones are proposed. Then, an approach is suggested for the synthesis and intercomparison of geohydromechanical processes in the EDZ for the four rock types (crystalline rock, salt, indurated clay, and plastic clay). Comparison tables of relevant processes, associated factors, and modeling and testing techniques are developed. A discussion of the general state-of-the-art and outstanding issues are also presented. A substantial bibliography of relevant papers on the subject is supplied at the end of the paper.

  19. Cratos: A Simple Low Power Excavation and Hauling System for Lunar Oxygen Production and General Excavation Tasks

    NASA Technical Reports Server (NTRS)

    Caruso, John J.; Greer, Lawrence C.; John, Wentworth T.; Spina, Dan C.; Krasowski, Mike J.; Abel, Phillip B.; Prokop, Norman F.; Flatico, Joseph M.; Sacksteder, Kurt R.

    2007-01-01

    The development of a robust excavating and hauling system for lunar and planetary excavation is critical to the NASA mission to the Moon and Mars. Cratos was developed as a low center of gravity, small (.75m x .75m x 0.3m), low power tracked test vehicle. The vehicle was modified to excavate and haul because it demonstrated good performance capabilities in a laboratory and field testing. Tested on loose sand in the SLOPE facility, the vehicle was able to pick up, carry, and dump sand, allowing it to accomplish the standard requirements delivery of material to a lunar oxygen production site. Cratos can pick up and deliver raw material to a production plant, as well as deliver spent tailings to a disposal site. The vehicle can complete many other In-Situ Resource Utilization (ISRU) excavation chores and in conjunction with another vehicle or with additional attachments may be able to accomplish all needed ISRU tasks.

  20. SN 2012hn: a tidal detonation event?

    NASA Astrophysics Data System (ADS)

    Maccarone, Thomas

    2013-09-01

    We propose for a 30 kilosecond observation of SN 2102hn, a Ca-rich gap transient. These enigmatic objects, with properties intermediate between those of classical novae and Type Ia supernovae, can be well-explained by tidal detonations of low mass white dwarfs by intermediate mass black holes. In such a case, fall-back accretion of the tidal debris would power an X-ray source for which we propose to search. Because supermassive black holes will swallow white dwarfs whole, a successful outcome to this proposal would both explain the Ca-rich gap transients *and* establish the existence of intermediate mass black holes.

  1. Shock-to-Detonation Transition simulations

    SciTech Connect

    Menikoff, Ralph

    2015-07-14

    Shock-to-detonation transition (SDT) experiments with embedded velocity gauges provide data that can be used for both calibration and validation of high explosive (HE) burn models. Typically, a series of experiments is performed for each HE in which the initial shock pressure is varied. Here we describe a methodology for automating a series of SDT simulations and comparing numerical tracer particle velocities with the experimental gauge data. Illustrative examples are shown for PBX 9502 using the HE models implemented in the xRage ASC code at LANL.

  2. Detonation Reaction Zones in Condensed Explosives

    SciTech Connect

    Tarver, C M

    2005-07-14

    Experimental measurements using nanosecond time resolved embedded gauges and laser interferometric techniques, combined with Non-Equilibrium Zeldovich--von Neumann--Doring (NEZND) theory and Ignition and Growth reactive flow hydrodynamic modeling, have revealed the average pressure/particle velocity states attained in reaction zones of self-sustaining detonation waves in several solid and liquid explosives. The time durations of these reaction zone processes is discussed for explosives based on pentaerythritol tetranitrate (PETN), nitromethane, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), triaminitrinitrobenzene(TATB) and trinitrotoluene (TNT).

  3. Impact waves and detonation. Part I

    NASA Technical Reports Server (NTRS)

    Becker, R

    1929-01-01

    Among the numerous thermodynamic and kinetic problems that have arisen in the application of the gaseous explosive reaction as a source of power in the internal combustion engine, the problem of the mode or way by which the transformation proceeds and the rate at which the heat energy is delivered to the working fluid became very early in the engine's development a problem of prime importance. The work of Becker here given is a notable extension of earlier investigations, because it covers the entire range of the explosive reaction in gases - normal detonation and burning.

  4. DDT and detonation waves in dust-air mixtures

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Grönig, H.; van de Ven, A.

    This paper summarizes the studies of DDT and stable detonation waves in dust-air mixtures at the Stosswellenlabor of RWTH Aachen. The DDT process and propagation mechanism for stable heterogeneous dust detonations in air are essentially the same as in the oxygen environment studied previously. The dust DDT process in tubes is composed of a reaction compression stage followed by a reaction shock stage as the pre-detonation process. The transverse waves that couple the shock wave and the chemical energy release are responsible for the propagation of a stable dust-air detonation. However, the transverse wave spacing of dust-air mixtures is much larger. Therefore, DDT and propagation of a stable detonation in most industrial and agricultural, combustible dust-air mixtures require a tube that has a large diameter between 0.1 m and 1 m and a sufficient length-diameter ratio beyond 100, when an appropriately strong initiation energy is used. Two dust detonation tubes, 0.14 m and 0.3 m in diameter, were used for observation of the above-mentioned results in cornstarch, anthraquinone and aluminum dust suspended in air. Smoked-foil technique was also used to measure the cellular structure of dust detonations in the 0.3 m detonation tube.

  5. Computation of a diverging Comp-B detonation

    SciTech Connect

    Bukiet, B.G.

    1989-01-01

    The expansion which occurs in diverging detonations weakens the wave and yields pressures and densities below those occurring in planar geometry. We study the problem of a spherically expanding detonation of Comp-B. The effect of varying the order of reaction as well as the rate law parameters (using an Arrhenius burn model) is studied. 14 refs., 3 figs.

  6. Gas-phase detonation propagation in mixture composition gradients.

    PubMed

    Kessler, D A; Gamezo, V N; Oran, E S

    2012-02-13

    The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that one-dimensional detonation properties of model low- and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon-air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuel-lean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient. PMID:22213660

  7. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, Hugh Douglas

    2002-01-01

    A pulse detonation engine (PDE) uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Lack of mixture uniformity is commonly ignored when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform H2/air mixtures were analyzed using the SPARK two-dimensional Navier-Stokes CFD code with 7-step H2/air reaction mechanism. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios (phi), stoichiometric (phi = 1.00), fuel lean (phi = 0.90), and fuel rich (phi = 1.10), were studied. All mixtures were detonable throughout the detonation tube. It was found that various mixtures representing the same test section equivalence ratio had specific impulses within 1 percent of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance.

  8. Modelling of detonation cellular structure in aluminium suspensions

    NASA Astrophysics Data System (ADS)

    Briand, A.; Veyssiere, B.; Khasainov, B. A.

    2010-12-01

    Heterogeneous detonations involving aluminium suspensions have been studied for many years for industrial safety policies, and for military and propulsion applications. Owing to their weak detonability and to the lack of available experimental results on the detonation cellular structure, numerical simulations provide a convenient way to improve the knowledge of such detonations. One major difficulty arising in numerical study of heterogeneous detonations involving suspensions of aluminium particles in oxidizing atmospheres is the modelling of aluminium combustion. Our previous two-step model provided results on the effect on the detonation cellular structure of particle diameter and characteristic chemical lengths. In this study, a hybrid model is incorporated in the numerical code EFAE, combining both kinetic and diffusion regimes in parallel. This more realistic model provides good agreement with the previous two-step model and confirms the correlations found between the detonation cell width, and particle diameter and characteristic lengths. Moreover, the linear dependence found between the detonation cell width and the induction length remains valid with the hybrid model.

  9. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Deenergized circuits near detonators. 57.6402 Section 57.6402 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL...

  10. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Deenergized circuits near detonators. 56.6402... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits...

  11. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deenergized circuits near detonators. 57.6402 Section 57.6402 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL...

  12. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deenergized circuits near detonators. 56.6402... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits...

  13. 33 CFR 154.820 - Fire, explosion, and detonation protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Fire, explosion, and detonation... Systems § 154.820 Fire, explosion, and detonation protection. (a) A vapor control system with a single... oxygen analyzer that samples the vapor concentration continuously at a point not more than 6 meters...

  14. 33 CFR 154.820 - Fire, explosion, and detonation protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Fire, explosion, and detonation... Systems § 154.820 Fire, explosion, and detonation protection. (a) A vapor control system with a single... oxygen analyzer that samples the vapor concentration continuously at a point not more than 6 meters...

  15. 33 CFR 154.820 - Fire, explosion, and detonation protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Fire, explosion, and detonation... Systems § 154.820 Fire, explosion, and detonation protection. (a) A vapor control system with a single... oxygen analyzer that samples the vapor concentration continuously at a point not more than 6 meters...

  16. 33 CFR 154.820 - Fire, explosion, and detonation protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fire, explosion, and detonation... Systems § 154.820 Fire, explosion, and detonation protection. (a) A vapor control system with a single... oxygen analyzer that samples the vapor concentration continuously at a point not more than 6 meters...

  17. Numerical analysis of thermonuclear detonation in dense plasma

    NASA Astrophysics Data System (ADS)

    Avronin, Y. N.; Bunatyan, A. A.; Gadzhiyev, A. D.; Mustafin, K. A.; Nurbakov, A. S.; Pisarev, V. N.; Feoktistov, L. P.; Frolov, V. D.; Shibarshov, L. I.

    1985-01-01

    The propagation of thermonuclear combustion from the region heated to thermonuclear temperatures by an external source to the remaining part of the target was investigated. The target was a tube of inert material (gold, lead, beryllium, etc.) filled with a deuterium-tritium mixture. It was determined analytically that thermonuclear combustion can propagate from a small portion of a nonspherical target to the remainder of the target and that a steady-state thermonuclear detonation wave can be formed. The role of various physical processes in thermonuclear detonation was investigated. Shock wave is the main mechanism underlying detonation propagation. The detonation rate and intensity of the thermonuclear reaction is influenced by the leakage of heat due to transvere heat conductivity. The critical diameter for thermonuclear detonation was determined approximately for a plasma filament encased in a housing with twice the density of the fuel.

  18. Multidimensional detonation propagation modeled via nonlinear shock wave superposition

    NASA Astrophysics Data System (ADS)

    Higgins, Andrew; Mehrjoo, Navid

    2010-11-01

    Detonation waves in gases are inherently multidimensional due to their cellular structure, and detonations in liquids and heterogeneous solids are often associated with instabilities and stochastic, localized reaction centers (i.e., hot spots). To explore the statistical nature of detonation dynamics in such systems, a simple model that idealizes detonation propagation as an ensemble of interacting blast waves originating from spatially random point sources has been proposed. Prior results using this model exhibited features that have been observed in real detonating systems, such as anomalous scaling between axisymmetric and two-dimensional geometries. However, those efforts used simple linear superposition of the blast waves. The present work uses a model of blast wave superposition developed for multiple-source explosions (the LAMB approximation) that incorporates the nonlinear interaction of shock waves analytically, permitting the effect of a more physical model of blast wave interaction to be explored. The results are suggestive of a universal behavior in systems of spatially randomized energy sources.

  19. Effect of prill structure on detonation performance of ANFO

    SciTech Connect

    Salyer, Terry R; Short, Mark; Kiyanda, Charles B; Morris, John S; Zimmerly, Tony

    2010-01-01

    While the effects of charge diameter, fuel mix ratio, and temperature on ANFO detonation performance are substantial, the effects of prill type are considerable as well as tailorable. Engineered AN prills provide a means to improve overall performance, primarily by changing the material microstructure through the addition of features designed to enhance hot spot action. To examine the effects of prill type (along with fuel mix ratio and charge diameter) on detonation performance, a series of precision, large-scale, ANFO front-curvature rate-stick tests was performed. Each shot used standard No. 2 diesel for the fuel oil and was essentially unconfined with cardboard confinement. Detonation velocities and front curvatures were measured while actively maintaining consistent shot temperatures. Based on the experimental results, DSD calibrations were performed to model the detonation performance over a range of conditions, and the overall effects of prill microstructure were examined and correlated with detonation performance.

  20. Light detonation wave in a cylindrical Z-pinch

    NASA Astrophysics Data System (ADS)

    Yusupaliev, U.; Sysoev, N. N.; Shuteev, S. A.; Elenskii, V. G.

    2015-09-01

    A secondary compression wave previously observed by other researchers in a cylindrical Z-pinch has been identified in this work as a light detonation wave. It appears on the inner surface of a discharge chamber under the action of the intense ultraviolet radiation from a plasma pinch at the stage of its maximum compression. The condition of the light detonation wave has been determined experimentally. The dependence of its Mach number on a generalized dimensionless variable has been determined taking into account the conservation laws for the light detonation wave including the pressure of the gas, expenses on the formation of the surface plasma, and the energy of ionization of the gas involved in the wave. An analogy with the laser-supported detonation wave created by intense laser radiation has been revealed. The indicated dependence is within the error of measurement in agreement with the experimental data for light detonation waves created by both methods.

  1. Atomistic simulation of detonation initiation by ultra-short impact

    NASA Astrophysics Data System (ADS)

    Murzov, S. A.; Zhakhovsky, V. V.

    2015-11-01

    We present results of the classical molecular dynamics simulation of detonation initiation in simple AB model of a high explosive compressed by ultra-short shock wave (SW). The simplified reactive empirical bond order potential (REBO) defines interatomic forces in the AB model explosive made up of diatomic AB molecules. Simulation of ultra-short piston-driven compression of AB explosive with duration of picoseconds represents an indirect initiation via a thin metal foil irradiated by a femtosecond laser pulse. We studied transition of SW to a detonation wave (DW), including evolution of calculated pressure profile in a sample. A run distance to detonation of such AB explosive film, which is required for detonation initiation, was obtained. Variation of loading time and piston velocity gives a 2D region of transition from SW to DW. The influence of pores on detonation initiation threshold is discussed.

  2. Detonation engine fed by acetylene-oxygen mixture

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Betelin, V. B.; Nikitin, V. F.; Phylippov, Yu. G.; Koo, Jaye

    2014-11-01

    The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman-Jouguet detonation parameters.

  3. Measuring In-Situ Mdf Velocity Of Detonation

    DOEpatents

    Horine, Frank M.; James, Jr., Forrest B.

    2005-10-25

    A system for determining the velocity of detonation of a mild detonation fuse mounted on the surface of a device includes placing the device in a predetermined position with respect to an apparatus that carries a couple of sensors that sense the passage of a detonation wave at first and second spaced locations along the fuse. The sensors operate a timer and the time and distance between the locations is used to determine the velocity of detonation. The sensors are preferably electrical contacts that are held spaced from but close to the fuse such that expansion of the fuse caused by detonation causes the fuse to touch the contact, causing an electrical signal to actuate the timer.

  4. On the Initiation Mechanism in Exploding Bridgewire and Laser Detonators

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Thomas, Keith A.; Clarke, S.; Mallett, H.; Martin, E.; Martinez, M.; Munger, A.; Saenz, Juan

    2006-07-01

    Since its invention by Los Alamos during the Manhattan Project era the exploding bridgewire detonator (EBW) has seen tremendous use and study. Recent development of a laser-powered device with detonation properties similar to an EBW is reviving interest in the basic physics of the deflagration-to-detonation (DDT) process in both of these devices. Cutback experiments using both laser interferometry and streak camera observations are providing new insight into the initiation mechanism in EBWs. These measurements are being correlated to a DDT model of compaction to detonation and shock to detonation developed previously by Xu and Stewart. The DDT model is incorporated into a high-resolution, multi-material model code for simulating the complete process. Model formulation and the modeling issues required to describe the test data will be discussed.

  5. Jaguar Procedures for Detonation Behavior of Explosives Containing Boron

    NASA Astrophysics Data System (ADS)

    Stiel, L. I.; Baker, E. L.; Capellos, C.

    2009-12-01

    The Jaguar product library was expanded to include boron and boron containing products by analysis of Available Hugoniot and static volumetric data to obtain constants of the Murnaghan relationships for the components. Experimental melting points were also utilized to obtain the constants of the volumetric relationships for liquid boron and boron oxide. Detonation velocities for HMX—boron mixtures calculated with these relationships using Jaguar are in closer agreement with literature values at high initial densities for inert (unreacted) boron than with the completely reacted metal. These results indicate that the boron does not react near the detonation front or that boron mixtures exhibit eigenvalue detonation behavior (as shown by some aluminized explosives), with higher detonation velocities at the initial points. Analyses of calorimetric measurements for RDX—boron mixtures indicate that at high boron contents the formation of side products, including boron nitride and boron carbide, inhibits the detonation properties of the formulation.

  6. Nuclear forensics: Soil content

    SciTech Connect

    Beebe, Merilyn Amy

    2015-08-31

    Nuclear Forensics is a growing field that is concerned with all stages of the process of creating and detonating a nuclear weapon. The main goal is to prevent nuclear attack by locating and securing nuclear material before it can be used in an aggressive manner. This stage of the process is mostly paperwork; laws, regulations, treaties, and declarations made by individual countries or by the UN Security Council. There is some preliminary leg work done in the form of field testing detection equipment and tracking down orphan materials; however, none of these have yielded any spectacular or useful results. In the event of a nuclear attack, the first step is to analyze the post detonation debris to aid in the identification of the responsible party. This aspect of the nuclear forensics process, while reactive in nature, is more scientific. A rock sample taken from the detonation site can be dissolved into liquid form and analyzed to determine its chemical composition. The chemical analysis of spent nuclear material can provide valuable information if properly processed and analyzed. In order to accurately evaluate the results, scientists require information on the natural occurring elements in the detonation zone. From this information, scientists can determine what percentage of the element originated in the bomb itself rather than the environment. To this end, element concentrations in soils from sixty-nine different cities are given, along with activity concentrations for uranium, thorium, potassium, and radium in various building materials. These data are used in the analysis program Python.

  7. Detonation characteristics of dimethyl ether and ethanol-air mixtures

    NASA Astrophysics Data System (ADS)

    Diakow, P.; Cross, M.; Ciccarelli, G.

    2015-05-01

    The detonation cell structure in dimethyl ether vapor and ethanol vapor-air mixtures was measured at atmospheric pressure and initial temperatures in the range of 293-373 K. Tests were carried out in a 6.2-m-long, 10-cm inner diameter tube. For more reactive mixtures, a series of orifice plates were used to promote deflagration-to-detonation transition in the first half of the tube. For less reactive mixtures prompt detonation initiation was achieved with an acetylene-oxygen driver. The soot foil technique was used to capture the detonation cell structure. The measured cell size was compared to the calculated one-dimensional detonation reaction zone length. For fuel-rich dimethyl ether mixtures the calculated reaction zone is highlighted by a temperature gradient profile with two maxima, i.e., double heat release. The detonation cell structure was interpreted as having two characteristic sizes over the full range of mixture compositions. For mixtures at the detonation propagation limits the large cellular structure approached a single-head spin, and the smaller cells approached the size of the tube diameter. There is little evidence to support the idea that the two cell sizes observed on the foils are related to the double heat release predicted for the rich mixtures. There was very little influence of initial temperature on the cell size over the temperature range investigated. A double heat release zone was not predicted for ethanol-air detonations. The detonation cell size for stoichiometric ethanol-air was found to be similar to the size of the small cells for dimethyl ether. The measured cell size for ethanol-air did not vary much with composition in the range of 30-40 mm. For mixtures near stoichiometric it was difficult to discern multiple cell sizes. However, near the detonation limits there was strong evidence of a larger cell structure similar to that observed in dimethyl ether air mixtures.

  8. Characterization of detonator performance using photonic Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Maisey, Matthew P.; Bowden, Mike D.

    2008-08-01

    Detonators are used to convert electrical or other energy into an explosive output. This output can then be used to initiate further explosive charges. To aid in the development of explosive systems, it is important to characterize the output of detonators, in particularly the pressure produced. Recent advances over the last five years in high-speed digitizing oscilloscopes and high-bandwidth photodiodes, driven primarily by the telecommunications industry, have enabled the development of a new type of interferometer for measuring high velocities, such as those found in detonics experiments. The Photonic Doppler Velocimeter (PDV) can be visualized as a fiber-based Michelson interferometer. The light from a single-mode fiber laser at 1550 nm is passed through a circulator, which acts to separate bi-directional light. The beam is then reflected via free-space optics off the surface of interest, and then focused back into the same fiber. This reflected light is then mixed with an approximately equal amount of non-reflected light, and the resulting interference is recorded using a high-bandwidth photodiode and oscilloscope. In contrast to more traditional Velocimetry techniques such as VISAR, only a single data channel is required. We have used our PDV system to investigate the performance of optical and electrical detonators. The detonators examined are the commercially available RISI RP-80, and an AWE DOI (Direct Optical Initiation) detonator. The RP-80 is an exploding bridgewire (EBW) detonator, utilizing Pentaerythritol Tetranitrate as the initiating explosive and a RDX output pellet. The DOI detonator uses an aluminum flyer to initiate a Hexanitrostilbene (HNS) pellet. Both detonators are canned in aluminum and the velocity of the can was measured, and from this, the output pressure of the detonator has been determined. This is compared to calculated values.

  9. On the influence of low initial pressure and detonation stochastic nature on Mach reflection of gaseous detonation waves

    NASA Astrophysics Data System (ADS)

    Wang, C. J.; Guo, C. M.

    2014-09-01

    The two-dimensional, time-dependent and reactive Navier-Stokes equations were solved to obtain an insight into Mach reflection of gaseous detonation in a stoichiometric hydrogen-oxygen mixture diluted by 25 % argon. This mixture generates a mode-7 detonation wave under an initial pressure of 8.00 kPa. Chemical kinetics was simulated by an eight-species, forty-eight-reaction mechanism. It was found that a Mach reflection mode always occurs for a planar detonation wave or planar air shock wave sweeping over wedges with apex angles ranging from to . However, for cellular detonation waves, regular reflection always occurs first, which then transforms into Mach reflection. This phenomenon is more evident for detonations ignited under low initial pressure. Low initial pressure may lead to a curved wave front, that determines the reflection mode. The stochastic nature of boundary shape and transition distance, during deflagration-to-detonation transition, leads to relative disorder of detonation cell location and cell shape. Consequently, when a detonation wave hits the wedge apex, there appears a stochastic variation of triple point origin and variation of the angle between the triple point trajectory and the wedge surface. As the wedge apex angle increases, the distance between the triple point trajectory origin and the wedge apex increases, and the angle between the triple point trajectory and the wedge surface decreases exponentially.

  10. Bonfire-safe low-voltage detonator

    DOEpatents

    Lieberman, Morton L.

    1990-01-01

    A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half.

  11. Bonfire-safe low-voltage detonator

    DOEpatents

    Lieberman, M.L.

    1988-07-01

    A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half. 2 figs.

  12. Spark-safe low-voltage detonator

    DOEpatents

    Lieberman, Morton L.

    1989-01-01

    A column of explosive in a low-voltage detonator which makes it spark-safe ncludes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4) each of which has an axial thickness-to-diameter ratio of one to two.

  13. Numerical solution of under-resolved detonations

    NASA Astrophysics Data System (ADS)

    Tosatto, Luca; Vigevano, Luigi

    2008-02-01

    A new fractional-step method is proposed for the numerical solution of high speed reacting flows, where the chemical time scales are often much smaller than the fluid dynamical time scales. When the problem is stiff, because of insufficient spatial/temporal resolution, a well-known spurious numerical phenomenon occurs in standard finite volume schemes: the incorrect calculation of the speed of propagation of discontinuities. The new method is first illustrated considering a one-dimensional scalar hyperbolic advection/reaction equation with stiff source term, which may be considered as a model problem to under-resolved detonations. During the reaction step, the proposed scheme replaces the cell average representation with a two-value reconstruction, which allows us to locate the discontinuity position inside the cell during the computation of the source term. This results in the correct propagation of discontinuities even in the stiff case. The method is proved to be second-order accurate for smooth solutions of scalar equations and is applied successfully to the solution of the one-dimensional reactive Euler equations for Chapman-Jouguet detonations.

  14. The dynamics of unsteady detonation in ozone

    SciTech Connect

    Aslam, Tariq D; Powers, Joseph M

    2008-01-01

    An ultra-fine, sub-micron discrete grid is used to capture the unsteady dynamics of a one-dimensional detonation in an inviscid O - O{sub 2} - O{sub 3} mixture. The ultra-fine grid is necessary to capture the length scales revealed by a complementary analysis of the steady detonation wave structure. For the unsteady calculations, shock-fitting coupled with a high order spatio-temporal discretization scheme combine to render numerical corruption negligible. As a result, mathematically verified solutions for a mixture initially of all O{sub 3} at one atmosphere and 298.15 K have been obtained; the solutions are converging at a rate much faster than the sub-first order convergence rate of all shock-capturing schemes. Additionally, the model has been validated against limited experimental data. Transient calculations show that strongly overdriven waves are stable and moderately overdriven waves unstable. New limit cycle behavior is revealed, and the first high resolution bifurcation diagram for etonation with detailed kinetics is found.

  15. Prompt Reaction of Aluminum in Detonating Explosives

    NASA Astrophysics Data System (ADS)

    Sandusky, Harold

    2005-07-01

    The potential of aluminum reaction to boost detonation energy has been studied for decades, most recently spurred by the availability of nanometer-sized particles. A review of the literature provides perspective for a recent study with the small-scale shock reactivity test. In this test, <1/2-g samples in confinement are shock loaded on one end, and the output at the other end dents a soft witness block. One test series had 0.3 g of HMX mixed with various forms of aluminum added in amounts of up to 25% of the total sample mass, with the deepest dent for H-5 aluminum occuring at 15%. Test results on ammonium perchlorate mixed with H-5 aluminum were consistent with the peak in detonation velocity reported in Combustion and Flame by Price in 1973 on similar mixtures. One outcome of this study is a new interpretation for the participation of aluminum in large scale gap tests on plastic-bonded explosives, which was discussed by Bernecker at this meeting in 1987.

  16. Pulse Detonation Rocket MHD Power Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    A pulse detonation research engine (MSFC (Marshall Space Flight Center) Model PDRE (Pulse Detonation Rocket Engine) G-2) has been developed for the purpose of examining integrated propulsion and magnetohydrodynamic power generation applications. The engine is based on a rectangular cross-section tube coupled to a converging-diverging nozzle, which is in turn attached to a segmented Faraday channel. As part of the shakedown testing activity, the pressure wave was interrogated along the length of the engine while running on hydrogen/oxygen propellants. Rapid transition to detonation wave propagation was insured through the use of a short Schelkin spiral near the head of the engine. The measured detonation wave velocities were in excess of 2500 m/s in agreement with the theoretical C-J velocity. The engine was first tested in a straight tube configuration without a nozzle, and the time resolved thrust was measured simultaneously with the head-end pressure. Similar measurements were made with the converging-diverging nozzle attached. The time correlation of the thrust and head-end pressure data was found to be excellent. The major purpose of the converging-diverging nozzle was to configure the engine for driving an MHD generator for the direct production of electrical power. Additional tests were therefore necessary in which seed (cesium-hydroxide dissolved in methanol) was directly injected into the engine as a spray. The exhaust plume was then interrogated with a microwave interferometer in an attempt to characterize the plasma conditions, and emission spectroscopy measurements were also acquired. Data reduction efforts indicate that the plasma exhaust is very highly ionized, although there is some uncertainty at this time as to the relative abundance of negative OH ions. The emission spectroscopy data provided some indication of the species in the exhaust as well as a measurement of temperature. A 24-electrode-pair segmented Faraday channel and 0.6 Tesla permanent

  17. The Excavation and Remediation of the Sandia National Laboratories Chemical Waste Landfill

    SciTech Connect

    KWIECINSKI,DANIEL ALBERT; METHVIN,RHONDA KAY; SCHOFIELD,DONALD P.; YOUNG,SHARISSA G.

    1999-11-23

    The Chemical Waste Landfill (CWL) at Sandia National Laboratories/New Mexico (SNL/NM) is a 1.9-acre disposal site that was used for the disposal of chemical wastes generated by many of SNL/NM research laboratories from 1962 until 1985. These laboratories were primarily involved in the design, research and development of non-nuclear components of nuclear weapons and the waste generated by these labs included small quantities of a wide assortment of chemical products. A Resource Conservation and Recovery Act (RCRA) Closure Plan for the Chemical Waste Landfill was approved by the New Mexico Environment Department (NMED) in 1992. Subsequent site characterization activities identified the presence of significant amounts of chromium in the soil as far as 80 feet below ground surface (fbgs) and the delineation of a solvent plume in the vadose zone that extends to groundwater approximately 500 fbgs. Trichloroethylene (TCE) was detected in some groundwater samples at concentrations slightly above the drinking water limit of 5 parts per billion. In 1997 an active vapor extraction system reduced the size of the TCE vapor plume and for the last six quarterly sampling events groundwater samples have not detected TCE above the drinking water standard. A source term removal, being conducted as a Voluntary Corrective Measure (VCM), began in September 1998 and is expected to take up to two years. Four distinct disposal areas were identified from historical data and the contents of disposal pits and trenches in these areas, in addition to much of the highly contaminated soil surrounding the disposal cells, are currently being excavated. Buried waste and debris are expected to extend to a depth of 12 to 15 fbgs. Excavation will focus on the removal of buried debris and contaminated soil in a sequential, area by area manner and will proceed to whatever depth is required in order to remove all pit contents. Up to 50,000 cubic yards of soil and debris will be removed and managed during

  18. Graphene nanosheets produced via controlled detonation of hydrocarbons

    NASA Astrophysics Data System (ADS)

    Nepal, Arjun

    We demonstrated that gram quantities of pristine graphene nanosheets (GNs) can be produced via detonation of a hydrocarbon. This one-step and catalyst-free method is eco-friendly and economical for the production of GNs. The hydrocarbons detonated were C2H2, C 2H4, C3H8 and CH4 in the presence of O2. The carbon products obtained from the detonation were analyzed by XRD, TEM, XPS and Raman spectroscopy. Depending upon the ratio of O2 to C2H2, the GNs of size up to ˜ 250 nm, SSA up to ˜ 200 m2/g and yield up to 70% with 2-3 layers' stack have been obtained so far. N2O was determined as a good alternative to O2 as an oxidizer to produce GNs by detonating C2H2 with it. A two-color pyrometer was designed and calibrated to measure the temperature of the detonation of hydrocarbons. The measured detonation temperatures were in between 2700 K and 4300 K. Along with the high detonation temperature, the composition of precursor hydrocarbon was observed to be crucial as well to determine its suitability to detonate with oxidizer to produce GNs. The hydrocarbons C2H2 and C2H4 were determined as the suitable precursors to produce GNs whereas detonation of C3H8 yields mere amorphous carbon soot and CH4 gives no solid carbon while detonated with O2. It has been proposed that the hydrocarbons with C/H≥0.5 are suitable for GNs production by detonation method. Highly oxidized graphene nanosheets (OGNs) were produced by solution-based oxidation of GNs prepared via a controlled detonation of acetylene at O 2/C2H2=0.8. The produced OGNs were about 250 nm in size and hydrophilic in nature. The C/O ratio was dramatically reduced from 49:1 in the pristine GNs to about 1:1 in OGNs, as determined by X-ray photoelectron spectroscopy. This C/O in OGNs is the least ever found in all oxidized graphitic materials that have been reported. Thus, the OGNs produced from the detonated GNs with such high degree of oxidation herein yields a novel and promising material for future applications.

  19. Collective workload organization in confined excavation of granular media

    NASA Astrophysics Data System (ADS)

    Monaenkova, Daria; Linevich, Vadim; Goodisman, Michael A.; Goldman, Daniel I.

    2015-03-01

    Many social insects collectively construct large nests in complex substrates; such structures are often composed of narrow tunnels. The benefits of collective construction, including reduced construction costs per worker come with challenges of navigation in crowded, confined spaces. Here we study the workforce organization of groups of S. invicta fire ants creating tunnels in wet granular media. We monitor the activity levels of marked (painted) workers-defined as a number of tunnel visits over 12 hours- during initiation of tunnels. The activity levels are described by a Lorenz curve with a Gini coefficient of ~ 0 . 7 indicating that a majority of the excavation is performed by a minority of workers. We hypothesize that this workload distribution is beneficial for excavation in crowded conditions, and use a 2D cellular automata (CA) model to reproduce behaviors of the excavating ants. CA simulations reveal that tunnel construction rates decrease in groups of equally active animals compared to groups with the natural workload distribution. We use predictions of the CA model to organize collective excavation of granular material by teams of digging robots, and use the robots to test hypotheses of crowded excavation in the physical world. We acknowledge support of National Science Foundation, Physics of Living Systems division.

  20. 33 CFR 154.822 - Detonation arresters, flame arresters, and flame screens.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Detonation arresters, flame... BULK Vapor Control Systems § 154.822 Detonation arresters, flame arresters, and flame screens. (a) Each detonation arrester required by this part must: (1) Be capable of arresting a detonation from either side...

  1. On the Initiation Mechanism in Exploding Bridgewire and Laser Detonators

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Thomas, K.; Saenz, J.

    2005-07-01

    Since its invention by Los Alamos during the Manhattan Project era the exploding bridgewire detonator (EBW) has seen tremendous use and study. Recent development of a laser-powered device with detonation properties similar to an EBW is reviving interest in the basic physics of the Deflagration-to-Detonation (DDT) process in both of these devices,[1]. Cutback experiments using both laser interferometry and streak camera observations are providing new insight into the initiation mechanism in EBWs. These measurements are being correlated to a DDT model of compaction to detonation and shock to detonation developed previously by Xu and Stewart, [2]. The DDT model is incorporated into a high-resolution, multi-material model code for simulating the complete process. Model formulation and predictions against the test data will be discussed. REFS. [1] A. Munger, J. Kennedy, A. Akinci, and K. Thomas, "Dev. of a Laser Detonator" 30th Int. Pyrotechnics Seminar, Fort Collins, CO, (2004). [2] Xu, S. and Stewart, D. S. Deflagration to detonation transition in porous energetic materials: A model study. J. Eng. Math., 31, 143-172 (1997)

  2. Simplified modeling of transition to detonation in porous energetic materials

    SciTech Connect

    Stewart, D.S. ); Asay, B.W. ); Prasad, K. )

    1994-07-01

    A simplified model that can predict the transitions from compaction to detonation and shock to detonation is given with the aim of describing experiments in beds of porous HMX. In the case of compaction to detonation, the energy of early impact generates a slowly moving, convective-reactive deflagration that expands near the piston face and evolves in a manner that is characteristic of confined deflagration to detonation transition. A single-phase state variable theory is adopted in contrast to a two-phase axiomatic mixture theory. The ability of the porous material to compact is treated as an endothermic process. Reaction is treated as an exothermic process. The algebraic (Rankine--Hugoniot) steady wave analysis is given for inert compaction waves and steady detonation waves in a piston supported configuration, typical of the experiments carried out in porous HMX. A structure analysis of the steady compaction wave is given. Numerical simulations of deflagration to detonation are carried out for parameters that describe an HMX-like material and compared with the experiments. The simple model predicts the high density plug that is observed in the experiments and suggests that the leading front of the plug is a secondary compaction wave. A shock to detonation transition is also numerically simulated.

  3. Development of a chemical microthruster based on pulsed detonation

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Hsun; Lu, Tsung-Hsun

    2012-10-01

    The development of a microthruster based on gaseous pulsed detonation is presented in this study. The feasibility of cyclic valveless pulsed detonation at frequencies over 100 Hz is first experimentally investigated in a microchannel with 1 mm × 0.6 mm rectangular cross-section. Highly reactive ethylene/oxygen mixtures are utilized to reduce the time and distance required for the reaction wave to run up to detonation in a smooth channel. High-speed visualizations have shown that the reaction waves reach detonative state through highly repeatable flame acceleration and deflagration-to-detonation transition processes in the channel. The validated concepts are implemented for the development of an integrated pulsed detonation microthruster. The microthruster was fabricated using low temperature co-fired ceramic tape technology. The volume of the reaction channel in the microthruster was 58 mm3. Spark electrodes and ion probes were embedded in the ceramic microthruster. The channel and via holes were fabricated using laser cutting techniques. Ion probe measurements showed that the reaction wave propagated at velocities larger than 2000 m s-1 before reaching the channel exit. The pulsed detonation microthruster has been successfully operated at frequencies as high as 200 Hz.

  4. Detonation propagation in narrow gaps with various configurations

    NASA Astrophysics Data System (ADS)

    Monwar, M.; Yamamoto, Y.; Ishii, K.; Tsuboi, T.

    2007-08-01

    In general all detonation waves have cellular structure formed by the trajectory of the triple points. This paper aims to investigate experimentally the propagation of detonation in narrow gaps for hydrogen-oxygen-argon mixtures in terms of various gap heights and gap widths. The gap of total length 1500 mm was constructed by three pair of stainless plates, each of them was 500 mm in length, which were inserted in a detonation tube. The gap heights were varied from 1.2 mm to 3.0 mm while the gap widths were varied from 10 mm to 40 mm. Various argon dilution rates were tested in the present experiments to change the size of cellular structure. Attempts have been made by means of reaction front velocity, shock front velocity, and smoked foil to record variations of cellular structure inside the gaps. A combination probe composed of a pressure and an ion probe detected the arrival of the shock and the reaction front individually at one measurement point. Experimental results show that the number of the triple points contained in detonation front decreases with decrease in the gap heights and gap widths, which lead to larger cellular structures. For mixtures with low detonability, cell size is affected by a certain gap width although conversely cell size is almost independent of gap width. From the present result it was found that detonation propagation inside the gaps is strongly governed by the gap height and effects of gap width is dependent on detonability of mixtures.

  5. Stability Affects of Artificial Viscosity in Detonation Modeling

    SciTech Connect

    Vitello, P; Souers, P C

    2002-06-03

    Accurate multi-dimensional modeling of detonation waves in solid HE materials is a difficult task. To treat applied problems which contain detonation waves one must consider reacting flow with a wide range of length-scales, non-linear equations of state (EOS), and material interfaces at which the detonation wave interacts with other materials. To be useful numerical models of detonation waves must be accurate, stable, and insensitive to details of the modeling such as the mesh spacing, and mesh aspect ratio for multi-dimensional simulations. Studies we have performed show that numerical simulations of detonation waves can be very sensitive to the form of the artificial viscosity term used. The artificial viscosity term is included in our ALE hydrocode to treat shock discontinuities. We show that a monotonic, second order artificial viscosity model derived from an approximate Riemann solver scheme can strongly damp unphysical oscillations in the detonation wave reaction zone, improving the detonation wave boundary wall interaction. These issues are demonstrated in 2D model simulations presented of the 'Bigplate' test. Results using LX-I 7 explosives are compared with numerical simulation results to demonstrate the affects of the artificial viscosity model.

  6. Motivations for laser detonator and firing system developments

    NASA Astrophysics Data System (ADS)

    Kennedy, James E.

    2006-08-01

    For ordnance system and testing applications in which safety is paramount, laser detonators and firing systems are strong candidates. Both low-power (1 W) and high-power (~1 MW) laser-driven explosive devices provide safety against stray current and electrostatic discharges, including lightning. This article addresses only one class of high-power laser-driven detonators that provide prompt detonation - the laser-driven analog of electrical exploding bridgewire (EBW) detonatorsm which we call a "laser EBW." Coupling of laser power into a plasma and then to the explosive powder will be described. Drawing upon current initiatives within DOE laboratories, this talk will emphasize similarities between high-power laser detonators and high-power electrical detonators in terms of firing power requirements and development of deonation. In explosive testing applications, laser detonators provide separation of noisy electrical firing systems from diagnostic sensors that may be embedded in an experimental assembly. Laser detonators can be made without any metallic content, and that is desirable for radiography experiments. Feasibility of reliable transmission of a firing pulse through optical fibers is a key element in applications for missile ordnance, warhead firing, and other mobile systems. The preparation and characterization of fibers, and their capabilities and limitations are also discussed briefly.

  7. Optimum Performance of Explosives in a Quasistatic Detonation Cycle

    NASA Astrophysics Data System (ADS)

    Baker, Ernest; Stiel, Leonard

    2015-06-01

    Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmosperic pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT RDX, and aluminized compositions, maximum work effects. were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. As expected, detonation to the C-J point is found to result in the maximum net work in all cases.

  8. A Novel Energy Recovery System for Parallel Hybrid Hydraulic Excavator

    PubMed Central

    Li, Wei; Cao, Baoyu; Zhu, Zhencai; Chen, Guoan

    2014-01-01

    Hydraulic excavator energy saving is important to relieve source shortage and protect environment. This paper mainly discusses the energy saving for the hybrid hydraulic excavator. By analyzing the excess energy of three hydraulic cylinders in the conventional hydraulic excavator, a new boom potential energy recovery system is proposed. The mathematical models of the main components including boom cylinder, hydraulic motor, and hydraulic accumulator are built. The natural frequency of the proposed energy recovery system is calculated based on the mathematical models. Meanwhile, the simulation models of the proposed system and a conventional energy recovery system are built by AMESim software. The results show that the proposed system is more effective than the conventional energy saving system. At last, the main components of the proposed energy recovery system including accumulator and hydraulic motor are analyzed for improving the energy recovery efficiency. The measures to improve the energy recovery efficiency of the proposed system are presented. PMID:25405215

  9. Gaseous detonation-driven fracture of tubes

    NASA Astrophysics Data System (ADS)

    Chao, Tong Wa

    An experimental investigation of fracture response of aluminum 6061-T6 tubes under internal gaseous detonation loading has been carried out. The pressure load, with speeds exceeding 2 km/s, can be characterized as a pressure peak (ranging from 2 to 6 MPa) followed by an expansion wave. The unique combination of this particular traveling load and tube geometry produced fracture data not available before in the open literature. Experimental data of this type are useful for studying the fluid-structure-fracture interaction and various crack curving and branching phenomena, and also for validation for multi-physics and multi-scale modeling. Axial surface flaws were introduced to control the crack initiation site. Fracture threshold models were developed by combining a static fracture model and an extensively studied dynamic amplification factor for tubes under internal traveling loads. Experiments were also performed on hydrostatically loaded preflawed aluminum 6061-T6 tubes for comparison. Significantly different fracture behavior was observed and the difference was explained by fluid dynamics and energy considerations. The experiments yielded comparison on crack speeds, strain, and pressure histories. In other experiments, the specimens were also pre-torqued to control the propagation direction of the cracks. Measurements were made on the detonation velocity, strain history, blast pressure from the crack opening, and crack speeds. The curved crack paths were digitized. The Chapman-Jouguet pressure, initial axial flaw length, and torsion level were varied to obtain different crack patterns. The incipient crack kinking angle was found to be consistent with fracture under mixed-mode loading. High-speed movies of the fracture events and blast wave were taken and these were used in interpreting the quantitative data. Numerical simulations were performed using the commerical explicit finite-element software LS-Dyna. The detonation wave was modeled as a traveling boundary

  10. Theoretical modeling of converging and diverging detonation waves in solid and gaseous explosives

    NASA Astrophysics Data System (ADS)

    Tarver, C. M.; Urtiew, P. A.

    The ignition and growth reactive flow model of shock initiation and detonation accurately calculate detonation velocity radius data on spherically diverging and converging detonation waves in the solid explosive PBX-9404. The theory of converging detonation waves is reviewed. The effects of the final reaction product state, the variability of the heat of reaction, and the equations of state are discussed for converging detonation waves in gaseous and solid explosives. It is postulated that the reaction product states follow a locus of Chapman-Jouguet (CJ) states as the detonation velocity and pressure increase. In converging gaseous detonations the heat of reaction decreases and the adiabatic exponent increases as the detonation velocity increases. In converging detonations in solid explosives equation of state uncertainties dominate the calculations, and more experimental data on overdriven detonation waves are required for improved modeling.

  11. Remotely operated excavator needs assessment/site visit summary

    SciTech Connect

    Straub, J.; Haller, S.; Worsley, R.; King, M.

    1992-12-02

    The Uranium in Soils Integrated Demonstration requested an assessment of soil excavation needs relative to soil remediation. The following list identifies the DOE sites assessed: Mound Laboratory, Paducah Gaseous Diffusion Plant, Portsmouth Gaseous Diffusion Plant, Nevada Test Site, Lawrence Livermore National Laboratory, Rocky Flats Plant, Los Alamos National Laboratory, Sandia National Laboratory, Idaho National Engineering Laboratory, Hanford Site, and Fernald Site. The reviewed sites fall into one or more of the following three categories: production, EPA National Priorities List, or CERCLA (superfund) designation. Only three of the sites appear to have the need for a remotely operated excavator rope. Hanford and Idaho Falls have areas of high-level radioactive contamination either buried or in/under buildings. The Fernald site has a need for remote operated equipment of different types. It is their feeling that remote equipment can be used to remove the health dangers to humans by removing them from the area. Most interviewees stated that characterization technologies needs are more immediate concern over excavation. In addition, the sites do not have similar geographic conditions which would aid in the development of a generic precision excavator. The sites visited were not ready to utilize or provide the required design information necessary to draft a performance specification. This creates a strong case against the development of one type of ROPE for use at these sites. Assuming soil characterization technology/methodology is improved sufficiently to allow accurate and real time field characterization then development of a precision excavator might be pursued based on FEMP needs, since the FEMP`s sole scope of work is remediation. The excavator could then be used/tested and then later modified for other sites as warranted.

  12. Theoretical solution of the minimum charge problem for gaseous detonations

    SciTech Connect

    Ostensen, R.W.

    1990-12-01

    A theoretical model was developed for the minimum charge to trigger a gaseous detonation in spherical geometry as a generalization of the Zeldovich model. Careful comparisons were made between the theoretical predictions and experimental data on the minimum charge to trigger detonations in propane-air mixtures. The predictions are an order of magnitude too high, and there is no apparent resolution to the discrepancy. A dynamic model, which takes into account the experimentally observed oscillations in the detonation zone, may be necessary for reliable predictions. 27 refs., 9 figs.

  13. Decoupling and recoupling of detonation waves associated with sudden expansion

    NASA Astrophysics Data System (ADS)

    Pantow, E. G.; Fischer, M.; Kratzel, Th.

    1996-09-01

    Detonation propagation behavior associated with sudden expansions has been investigated both experimentally and numerically. Different mechanisms, from sustained propagation to detonation failure and reinitiation including shock and flame front decoupling and recoupling have been observed with the schlieren technique. The shock-induced flame propagation has been modeled with two-step chemistry and structured two-dimensional CFD on arbitrary geometries. The results of the numerical simulations show good correspondence to the variety of phenomena observed in experiments. Thus the numerical simulation can be used to study detonation propagation in complex geometries. It provides a tool for the design of safety devices and aids experimental investigations.

  14. Detonation of cryogenic gaseous hydrogen-oxygen mixtures

    NASA Technical Reports Server (NTRS)

    Plaster, M.; Mcclenagan, R. D.; Benz, F. J.; Shepherd, J. E.; Lee, J. H. S.

    1991-01-01

    The accidental mixing and detonation of oxygen-hydrogen mixtures is a serious aerospace industry hazard. The detonation characteristics of cryogenic mixtures of gaseous hydrogen and oxygen have accordingly been studied at various initial pressures and equivalence ratios at 100 K, and the results compared with numerical computations of idealized, steady-state, one-dimensional Zeldovich-von Neumann-Doering detonation structure with detailed chemical reaction kinetics. The predictions thus obtained for critical tube diameter, on the basis of calculated reaction-zone thickness, are found to agree reasonably well with experimental data.

  15. Geometry-specific scaling of detonation parameters from front curvature

    SciTech Connect

    Jackson, Scott I; Short, Mark

    2011-01-20

    It has previously been asserted that classical detonation curvature theory predicts that the critical diameter and the diameter-effect curve of a cylindrical high-explosive charge should scale with twice the thickness of an analogous two-dimensional explosive slab. The varied agreement of experimental results with this expectation have led some to question the ability of curvature-based concepts to predict detonation propagation in non-ideal explosives. This study addresses such claims by showing that the expected scaling relationship (hereafter referred to d = 2w) is not consistent with curvature-based Detonation Shock Dynamics (DSD) theory.

  16. KIVA reactive hydrodynamics code applied to detonations in high vacuum

    NASA Astrophysics Data System (ADS)

    Greiner, N. Roy

    1989-08-01

    The KIVA reactive hydrodynamics code was adapted for modeling detonation hydrodynamics in a high vacuum. Adiabatic cooling rapidly freezes detonation reactions as a result of free expansion into the vacuum. After further expansion, a molecular beam of the products is admitted without disturbance into a drift tube, where the products are analyzed with a mass spectrometer. How the model is used for interpretation and design of experiments for detonation chemistry is explained. Modeling of experimental hydrodynamic characterization by laser-schlieren imaging and model-aided mapping that will link chemical composition data to particular volume elements in the explosive charge are also discussed.

  17. The Physical Effects of Detonation in a Closed Cylindrical Chamber

    NASA Technical Reports Server (NTRS)

    Draper, C S

    1935-01-01

    Detonation in the internal-combustion engine is studied as a physical process. It is shown that detonation is accompanied by pressure waves within the cylinder charge. Sound theory is applied to the calculation of resonant pressure-wave frequencies. Apparatus is described for direct measurement of pressure-wave frequencies. Frequencies determined from two engines of different cylinder sizes are shown to agree with the values calculated from sound theory. An outline of the theoretically possible modes of vibration in a right circular cylinder with flat ends is included. An appendix by John P. Elting gives a method of calculating pressure in the sound wave following detonation.

  18. Multiple-cycle Simulation of a Pulse Detonation Engine Ejector

    NASA Technical Reports Server (NTRS)

    Yungster, S.; Perkins, H. D.

    2002-01-01

    This paper presents the results of a study involving single and multiple-cycle numerical simulations of various PDE-ejector configurations utilizing hydrogen-oxygen mixtures. The objective was to investigate the thrust, impulse and mass flow rate characteristics of these devices. The results indicate that ejector systems can utilize the energy stored in the strong shock wave exiting the detonation tube to augment the impulse obtained from the detonation tube alone. Impulse augmentation ratios of up to 1.9 were achieved. The axial location of the converging-diverging ejectors relative to the end of the detonation tube were shown to affect the performance of the system.

  19. Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance

    NASA Technical Reports Server (NTRS)

    Morris, C. I.

    2003-01-01

    Pulse detonation engines (PDB) have generated considerable research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional gas turbines and rocket engines. The detonative mode of combustion employed by these devices offers a theoretical thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional engines. However, the unsteady blowdown process intrinsic to all pulse detonation devices has made realistic estimates of the actual propulsive performance of PDES problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models.

  20. The development of a sonic boom simulator with detonable gases

    NASA Technical Reports Server (NTRS)

    Strugielski, R. T.; Fugelso, L. E.; Holmes, L. B.; Byrne, W. J.

    1971-01-01

    A sonic boom pressure profile was simulated in the far-field by detonation of a methane-oxygen mixture contained in a slender, shaped Mylar envelope. Ideal N-waves were synthesized with peak overpressures from two to five psf and durations of 30 to 75 milliseconds. The detonation of the gas mixture was initiated by a single Primacord strand running the length of balloon. The N-wave producing balloon was synthesized as a composite structure, utilizing experimental pressure profiles obtained from the detonations of slender, axisymmetric balloons with elementary, non-cylindrical shapes.

  1. Effect of Smoked Foil Thickness and Location on Detonation Initiation

    NASA Astrophysics Data System (ADS)

    Chung, K. M.; Wen, C. S.

    Smoked foil has been employed to visualize triple point pattern (or cell width), indicating detonation phenomena. However, the aluminum sheet also corresponds to sudden contraction in a smooth tube. It might induce early trigger on detonation initiation and result in a reduction in deflagration-to-detonation transition (DDT) run-up distance. Test results showed the thickness of aluminum sheet of less than 1.3 mm is required to eliminate the effect of smoked foil. A reduction in Xdtt is observed when the thickness of aluminum sheet increases.

  2. Cellular detonation diffraction in gas-particle mixtures

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Khmel, T. A.; Kratova, Y. V.

    2010-12-01

    Diffraction of cellular heterogeneous detonation out of a channel into open half-space in a mixture of aluminum particles and oxygen is investigated numerically. The flow is found to be very similar to gas detonation diffraction. The detonation weakening behind the step results in combustion front deceleration and decoupling from the leading shock wave. Subsequent re-initiation takes place in a transverse wave. New transverse waves are generated along the expanding front. The computations that were performed show that the critical number of cells is several times less than that for gases. This is confirmed by theoretical estimates based upon the Mitrofanov-Soloukhin approach.

  3. Asteroid Icy Regolith Excavation and Volatile Capture Project

    NASA Technical Reports Server (NTRS)

    Zeitlin, Nancy; Mantovani, James; Swanger, Adam; Townsend, Ivan

    2015-01-01

    Icy regolith simulants will be produced in a relevant vacuum environment using various minerals, including hydrated minerals, that are found in C-type meteorites and in other types of planetary regolith. This will allow us to characterize the mechanical strength of the icy regolith as a function of ice content using penetration, excavation, and sample capture devices. The results of this study will benefit engineers in designing efficient regolith excavators and ISRU processing systems for future exploration missions to asteroids and other planetary bodies.

  4. Remote Excavation System technology evaluation report: Buried Waste Robotics Program

    SciTech Connect

    Not Available

    1993-09-01

    This document describes the results from the Remote Excavation System demonstration and testing conducted at the Idaho National Engineering Laboratory during June and July 1993. The purpose of the demonstration was to ascertain the feasibility of the system for skimming soil and removing various types of buried waste in a safe manner and within all regulatory requirements, and to compare the performances of manual and remote operation of a backhoe. The procedures and goals of the demonstration were previously defined in The Remote Excavation System Test Plan, which served as a guideline for evaluating the various components of the system and discussed the procedures used to conduct the tests.

  5. Calculation of Excavation Force for ISRU on Lunar Surface

    NASA Technical Reports Server (NTRS)

    Zeng, Xiangwu (David); Burnoski, Louis; Agui, Juan H.; Wilkinson, Allen

    2007-01-01

    Accurately predicting the excavation force that will be encountered by digging tools on the lunar surface is a crucial element of in-situ resource utilization (ISRU). Based on principles of soil mechanics, this paper develops an analytical model that is relatively simple to apply and uses soil parameters that can be determined by traditional soil strength tests. The influence of important parameters on the excavation force is investigated. The results are compared with that predicted by other available theories. Results of preliminary soil tests on lunar stimulant are also reported.

  6. Geotechnical characterization and construction methods for SSC tunnel excavation

    SciTech Connect

    Nelson, P.P.; Lundin, T.K. Superconducting Super Collider Lab., Dallas, TX )

    1990-06-01

    The site for the Superconducting Super Collider (SSC) facility was selected in 1988 after a nationwide proposal competition. The selected site is located in Ellis County, Texas, surrounding the town of Waxahachie which is about 30 miles (48 km) south of the City of Dallas central business district. This paper will describe the geotechnical conditions anticipated for excavation at the SSC site. A general geologic and geomechanical description of the rock present will be followed by a summary of the site-specific conceptual design for the tunneled components of the SSC machine. The Supercollider project will include about 70 miles (113) km of tunnel excavation.

  7. Propagation of nitromethane detonations in porous media

    NASA Astrophysics Data System (ADS)

    Lee, J. J.; Frost, D. L.; Lee, J. H. S.; Dremin, A.

    1995-06-01

    The characteristics of the propagation of a detonation in chemically sensitized nitromethane in a dense porous medium are investigated. By introducing liquid NM+15% (by weight) DETA into densely packed beds of solid spherical glass beads 66μm to 2.4 mm in diameter, a highly heterogeneous explosive mixture is obtained. The critical (i.e., failure) charge diameter of this mixture is systematically measured in unconfined charges over a wide range of bead sizes. Velocity measurements are also made for the various charges. It is found that there exists a critical bead size above which the critical diameter decreases with increasing bead size and below which it decreases with decreasing bead size. This result indicates an abrupt change in the mechanism of propagation at the critical bead size. Velocity measurements further support this by emphasizing the different behavior above and below the critical point.

  8. Molecular Dynamics Simulation of Shock Induced Detonation

    NASA Astrophysics Data System (ADS)

    Tomar, Vikas; Zhou, Min

    2004-07-01

    This research focuses on molecular dynamics (MD) simulation of shock induced detonation in Fe2O3+Al thermite mixtures. A MD model is developed to simulate non-equilibrium stress-induced reactions. The focus is on establishing a criterion for reaction initiation, energy content and rate of energy release as functions of mixture and reinforcement characteristics. A cluster functional potential is proposed for this purpose. The potential uses the electronegativity equalization to account for changes in the charge of different species according to local environment. Parameters in the potential are derived to fit to the properties of Fe, Al, Fe2O3, and Al2O3. NPT MD simulations are carried out to qualitatively check the energetics of the forward (Fe2O3+Al) as well as backward (Al2O3+Fe) thermite reactions. The results show that the potential can account for the energetics of thermite reactions.

  9. Detonation Propagation through Nitromethane Embedded Metal Foam

    NASA Astrophysics Data System (ADS)

    Lieberthal, Brandon; Maines, Warren R.; Stewart, D. Scott

    2015-11-01

    There is considerable interest in developing a better understanding of dynamic behaviors of multicomponent systems. We report results of Eulerian hydrodynamic simulations of shock waves propagating through metal foam at approximately 20% relative density and various porosities using a reactive flow model in the ALE3D software package. We investigate the applied pressure and energy of the shock wave and its effects on the fluid and the inert material interface. By varying pore sizes, as well as metal impedance, we predict the overall effects of heterogeneous material systems at the mesoscale. In addition, we observe a radially expanding blast front in these heterogeneous models and apply the theory of Detonation Shock Dynamics to the convergence behavior of the lead shock.

  10. Analysis of pulse detonation turbojet engines

    NASA Astrophysics Data System (ADS)

    Vutthivithayarak, Ronnachai

    2011-12-01

    Research over the last two decades has shown the potential advantages of pulse detonation engines (PDEs) over existing aero-engines in terms of improved thermodynamics efficiency, improved thrust performance, simplicity of design, and flexibility to operate over a wide speed range. The inherently unsteady characteristic of PDEs makes it difficulty to analyze and evaluate their performance. The conventional method that relies on steady-state assumptions cannot be directly applied. PDE studies have to employ unsteady gasdynamics behavior. In this study, the thermodynamic cycle of a PDE, which can be called the ZND cycle, is theoretically analyzed. A parametric analysis of turbojet PDEs is considered for both ideal and non-ideal cases. The conventional turbojet with a Brayton cycle is brought in the comparison to verify that PDEs can provide better performance.

  11. The dynamics of unsteady detonation with diffusion

    SciTech Connect

    Aslam, Tariq Dennis; Romick, Christopher; Powers, Joseph

    2010-01-01

    Here we consider an unsteady detonation with diffusion included. This introduces an interaction between the reaction length scales and diffusion length scales. Detailed kinetics introduce multiple length scales as shown though the spatial eigenvalue analysis of hydrogen-oxygen system; the smallest length scale is {approx} 10{sup 7} m and the largest {approx} 10{sup -2} m; away from equilibrium, the breadth can be larger. In this paper, we consider a simpler set of model equations, similar to the inviscid reactive compressible fluid equations, but include diffusion (in the form of thermal/energy, momentum, and mass diffusion). We will seek to reveal how the complex dynamics already discovered in one-step systems in the inviscid limit changes with the addition of diffusion.

  12. Spark-safe low-voltage detonator

    DOEpatents

    Lieberman, M.L.

    1988-07-01

    A column of explosive in a low-voltage detonator which makes it spark-safe includes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4), each of which has an axial thickness-to-diameter ratio of one to two. 2 figs.

  13. Thermonuclear detonations ensuing white dwarf mergers

    NASA Astrophysics Data System (ADS)

    Dan, M.; Guillochon, J.; Brüggen, M.; Ramirez-Ruiz, E.; Rosswog, S.

    2015-12-01

    The merger of two white dwarfs (WDs) has for many years not been considered as the favoured model for the progenitor system of Type Ia supernovae (SNe Ia). But recent years have seen a change of opinion as a number of studies, both observational and theoretical, have concluded that they should contribute significantly to the observed SN Ia rate. In this paper, we study the ignition and propagation of detonation through post-merger remnants and we follow the resulting nucleosynthesis up to the point where a homologous expansion is reached. In our study we cover the entire range of WD masses and compositions. For the emergence of a detonation we study three different setups. The first two are guided by the merger remnants from our earlier simulations, while for the third one the ignitions were set by placing hotspots with properties determined by spatially resolved calculations taken from the literature. There are some caveats to our approach which we investigate. We carefully compare the nucleosynthetic yields of successful explosions with SN Ia observations. Only three of our models are consistent with all the imposed constraints and potentially lead to a standard Type Ia event. The first one, a 0.45 M⊙ helium (He) + 0.9 M⊙ carbon-oxygen (CO) WD system produces a sub-luminous, SN 1991bg-like event while the other two, a 0.45 M⊙ He+1.1 M⊙ oxygen-neon WD system and a 1.05 + 1.05 M⊙ system with two CO WDs, are good candidates for common SNe Ia.

  14. Effect of Diethylenetriamine and Triethylamine on Nitromethane Detonation

    NASA Astrophysics Data System (ADS)

    Lee, Julian J.; Jiang, Junping; Kooi Hoe, Choong; Lee, John H. S.

    1999-06-01

    Nitromethane (NM) has long been a popular explosive for the study of detonations in homogeneous and heterogeneous media, and once sensitized with certain chemical additives, it provides a convenient liquid explosive for laboratory experiments. The effect of chemical sensitizers on the decomposition of NM within a detonation front has not been fully understood yet. The critical diameter is a detonation property that has been directly related to the global reaction rate. In this work, the critical diameter in glass and Tygon^ TM tubes is measured with two chemical sensitizers: diethylenetriamine (DETA) and triethylamine (TEA), at previously unreported high concentrations, i.e. up to 20% (by mass) of DETA and up to 15% of TEA. Results show that the critical diameter reaches a minimum at 5% TEA and between 10% and 20% DETA. In addition, the detonation velocity indicates a strong dependence of the reaction rate on the thermodynamic state of the explosive.

  15. Explosive Products EOS: Adjustment for detonation speed and energy release

    SciTech Connect

    Menikoff, Ralph

    2014-09-05

    Propagating detonation waves exhibit a curvature effect in which the detonation speed decreases with increasing front curvature. The curvature effect is due to the width of the wave profile. Numerically, the wave profile depends on resolution. With coarse resolution, the wave width is too large and results in a curvature effect that is too large. Consequently, the detonation speed decreases as the cell size is increased. We propose a modification to the products equation of state (EOS) to compensate for the effect of numerical resolution; i.e., to increase the CJ pressure in order that a simulation propagates a detonation wave with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.

  16. Modeling of Explosion Gas Dynamics with Account of Detonation

    NASA Astrophysics Data System (ADS)

    Morozov, D. O.

    2013-11-01

    The physical and hydrodynamic processes in the initial phase of explosion of condensed explosives in the air have been considered. The role of the processes of energy release connected with the explosive detonation has been analyzed. The equations of formal kinetics for modeling the processes of transformation of the original substance into detonation products have been described. The results obtained with the use of the equation of state of an ideal gas with a constant adiabatic index have been compared with calculations, where for the equation of state wide-range tables of properties of the air and explosion products were used. The stage of detonation of an explosive is included in the self-consistent hydrodynamic model used for describing the explosion processes from the moment of initiation of the detonation wave to the moment the air shock wave is formed, as well as in describing its propagation and attenuation.

  17. Numerical simulation of H2/air detonation using unstructured mesh

    NASA Astrophysics Data System (ADS)

    Togashi, Fumiya; Löhner, Rainald; Tsuboi, Nobuyuki

    2009-06-01

    To explore the capability of unstructured mesh to simulate detonation wave propagation phenomena, numerical simulation of H2/air detonation using unstructured mesh was conducted. The unstructured mesh has several adv- antages such as easy mesh adaptation and flexibility to the complicated configurations. To examine the resolution dependency of the unstructured mesh, several simulations varying the mesh size were conducted and compared with a computed result using a structured mesh. The results show that the unstructured mesh solution captures the detailed structure of detonation wave, as well as the structured mesh solution. To capture the detailed detonation cell structure, the unstructured mesh simulations required at least twice, ideally 5times the resolution of structured mesh solution.

  18. Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morris, Christopher I.

    2003-01-01

    This viewgraph presentation provides information on the engine cycle of a pulse detonation rocket engine (PDRE), models for optimizing the performance of a PDRE, and the performance of PDREs in comparison to Solid State Rocket Engines (SSREs).

  19. Delayed detonation in propellants from low-velocity impact

    SciTech Connect

    Green, L.G.; James, E.; Lee, E.L.; Chambers, E.S.; Tarver, C.M.; Westmoreland, C.; Weston, A.M.; Brown, B.

    1981-01-01

    Certain high HMX-content propellants are found to undergo delayed detonation when cylinders of the propellant are subjected to axisymetric impact. The magnitude of the impact pressure is considerably less than that required for prompt shock initiation. It is also found that granular propellant (65 to 78% theoretical maximum density) packed in a thick-walled (50 mm) Plexiglas pipe is easily detonated by relatively low-velocity (130 m/s) piston compaction of the porous propellant. The above processes appear to be related to each other and to the more classical deflagration-to-detonation studies carried out in heavy-walled pipes where the explosive is deliberately ignited to start the build-up to detonation.

  20. Novel Small-scale Technique for Determining Detonation Velocity

    NASA Astrophysics Data System (ADS)

    Preston, Daniel; Hill, Larry; Tappan, Bryce

    2013-06-01

    Measuring the local detonation velocity of an explosive has been limited to rate stick and cylinder tests. These tests traditionally used break wires, pins, and more recently PDV as a velocity diagnostic. These experimental techniques can be very accurate at measuring detonation velocities but are costly and require tens to hundreds of grams of material. This paper presents a novel small-scale technique for inferring detonation velocity from a modest sized pellet of explosive. A streak image is taken of the breakout shock on the flat output side of the pellet. Assuming a spherical shock wave, one can show that the breakout trace is of hyperbolic form. From this, one can simultaneously infer detonation velocty and apparent center. This method is ideal for energetic formulation and synthesis development due to the small amount of material required. Furthermore, this paper discusses the accuracy and limitations of this technique.

  1. Non-ideal detonation behaviour of PBX 9502

    NASA Astrophysics Data System (ADS)

    Schoch, Stefan; Nikiforakis, Nikos

    2009-06-01

    Numerical experiments are performed investigating the non-ideal detonation behaviour of PBX 9502 in two setups. In the first setup we consider a three-dimensional rate stick experiment. A booster charge initiates a reaction front leading to a curved detonation wave. The numerical results are compared to theory and experimental evidence. The effects of weak and strong confinement are discussed. The second setup considers the so called ``hockey puck experiment.'' Experimental results show the appearance of a dead zone due to the effect of the geometry. This is captured by the numerical results, which also reveal that the initially spherical detonation is diffracted leading to local detonation failure. The numerical simulations are performed by solving a mathematical model for a three-phase medium based on the Euler equations. The numerical results are obtained using high-resolution shock-capturing methods combined with adaptive mesh refinement.

  2. [Detonation temperature measurement of epoxypropane using instantaneous spectrum method].

    PubMed

    Li, Ying; Li, Ping; Xiao, Hai-Bo; Hu, Dong; Yuan, Chang-Ying

    2008-03-01

    After solving the problems of synchronization of the measuring system and the avoidance of false trigger signal, the instantaneous emission spectrum of epoxypropane with an exposure time of 2 micros and a resolution of 0.2 nm was acquired from a side window of a shock tube at the very moment when the epoxypropane transformed from deflagration to detonation. The measuring system consists of an advanced intensified charge-coupled-device spectroscopic detector, a digital delay generator DG535, an explosion shock tube and optical fibers. The DDT process was monitored by pressure transducers. After correcting the intensity of the spectrum obtained, the background curve of the heat radiation intensity of the detonation was given immediately. The detonation temperature of 2 416 K for epoxypropane was derived from fitting the curve with Planck blackbody formula by least squares principle. The detonation temperature of epoxypropane can provide an experimental datum for analyzing the microscopic mechanism of DDT process. PMID:18536396

  3. Simulation Of Attenuation Regularity Of Detonation Wave In Pmma

    NASA Astrophysics Data System (ADS)

    Lan, Wei; Xiaomian, Hu

    2012-03-01

    Polymethyl methacrylate (PMMA) is often used as clapboard or protective medium in the parameter measurement of detonation wave propagation. Theoretical and experimental researches show that the pressure of shock wave in condensed material has the regularity of exponential attenuation with the distance of propagation. Simulation of detonation produced shock wave propagation in PMMA was conducted using a two-dimensional Lagrangian computational fluid dynamics program, and results were compared with the experimental data. Different charge diameters and different angles between the direction of detonation wave propagation and the normal direction of confined boundary were considered during the calculation. Results show that the detonation produced shock wave propagation in PMMA accords with the exponential regularity of shock wave attenuation in condensed material, and several factors are relevant to the attenuation coefficient, such as charge diameter and interface angle.

  4. Simulation of attenuation regularity of detonation wave in PMMA

    NASA Astrophysics Data System (ADS)

    Lan, Wei; Xiaomian, Hu

    2011-06-01

    Polymethyl methacrylate (PMMA) is often used as clapboard or protective medium in the parameter measurement of detonation wave propagation, due to its similar shock impedance with the explosive. Theoretical and experimental research show that the pressure of shock wave in condensed material has the regularity of exponential attenuation with the distance of propagation. Simulation of detonation wave propagation in PMMA is conducted using a two-dimensional Lagrangian computational fluid dynamics program, and results are compared with the experimental data. Different charge diameters and different angles between the direction of detonation wave propagation and the normal direction of confined boundary are considered during the calculation. Results show that the detonation wave propagation in PMMA accords with the exponential regularity of shock wave attenuation in condensed material, and several factors are relevant to the attenuation coefficient, such as charge diameter and interface angle.

  5. 33 CFR 154.2106 - Detonation arresters installation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... arrester, line size expansions must be in a straight pipe run and must be no closer than 120 times the pipe's diameter from the detonation arrester unless the manufacturer has test data to show the...

  6. Jaguar Analyses of Experimental Detonation Values for Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard I.; Baker, Ernest L.; Capellos, Christos

    2004-07-01

    Comparisons of JAGUAR C-J velocities with experimental detonation values for a number of explosives indicate that only slight, if any, aluminum reaction occurs at the detonation front even if small or sub-micron particles are utilized. For sub-micron particles, it is important to account for the presence of aluminum oxide in the explosive formulation. The agreement with the calculated JAGUAR values for zero aluminum reaction is within 2% for most experimental detonation velocities considered. Comparisons of experimental cylinder velocities by JAGUAR analytical procedures indicate that with small aluminum particles substantial aluminum reaction occurs at low values of the radial expansion, even though little reaction is observed at the detonation front.

  7. Frequency content of current pulses in slapper detonator bridges

    SciTech Connect

    Carpenter, K H

    2006-12-18

    DFT amplitudes are obtained for digital current pulse files. The frequency content of slapper detonator bridge current pulses is obtained. The frequencies are confined well within the passband of the CVR used to sample them.

  8. Nuclear explosive safety study process

    SciTech Connect

    1997-01-01

    Nuclear explosives by their design and intended use require collocation of high explosives and fissile material. The design agencies are responsible for designing safety into the nuclear explosive and processes involving the nuclear explosive. The methodology for ensuring safety consists of independent review processes that include the national laboratories, Operations Offices, Headquarters, and responsible Area Offices and operating contractors with expertise in nuclear explosive safety. A NES Study is an evaluation of the adequacy of positive measures to minimize the possibility of an inadvertent or deliberate unauthorized nuclear detonation, high explosive detonation or deflagration, fire, or fissile material dispersal from the pit. The Nuclear Explosive Safety Study Group (NESSG) evaluates nuclear explosive operations against the Nuclear Explosive Safety Standards specified in DOE O 452.2 using systematic evaluation techniques. These Safety Standards must be satisfied for nuclear explosive operations.

  9. Discontinuous behavior near excavations in a bedded salt formation

    SciTech Connect

    Stormont, J.C.

    1990-10-01

    Discontinuous behavior is being observed and measured in the vicinity of excavations constructed in a bedded salt formation 650 m below ground surface for the Waste Isolation Pilot Plant (WIPP) Facility. The 2 m thick salt layer in the immediate roof acts as a beam, shearing along a thin overlying anhydrite/clay seam. The floor of the excavations is comprised of a 1 m thick salt layer underlain by a 1 m thick predominately anhydrite layer (referred to as MB139). In the ribs, there is limited fracturing within the first meter of most larger excavations. Vertical fractures develop in pillars at most intersections. The discontinuous behavior is qualitatively consistent with analyses of the formation behaving as a layered medium (elastic beam analysis) and limited tensile and compressive failure of the rock salt. The significance of the discontinuous behavior is that can dominate the effective fluid transport properties of the formation near the excavation, and therefore requires considerations in the design of repository seals. Furthermore, the discontinuous behavior must be monitored and is a very important consideration in the maintenance program designed to assume a safe underground environment. 22 refs., 17 figs.

  10. 56. Historic photo of excavation work at Building 202, shows ...

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

    56. Historic photo of excavation work at Building 202, shows facility with exhaust scrubber in foreground, February 24, 1969. On file at NASA Plumbrook Research Center, Sandusky, Ohio. NASA photo number C-69-712. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  11. 55. Historic photo of excavation work at Building 202, shows ...

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

    55. Historic photo of excavation work at Building 202, shows facility with detention tank in foreground, February 24, 1969. On file at NASA Plumbrook Research Center, Sandusky, Ohio. NASA photo number C-69-711. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  12. CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING ...

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

    CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING (CPP-601) LOOKING NORTHWEST. INL PHOTO NUMBER NRTS-50-885. Unknown Photographer, 10/30/1950 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

  13. An Analysis of Excavation Support Safety Based on Experimental Studies

    NASA Astrophysics Data System (ADS)

    Gorska, Karolina; Wyjadłowski, Marek

    2015-09-01

    The article presents the results of inclinometric measurements and numerical analyses of soldier-pile wall displacements. The excavation under investigation was made in cohesive soils. The measurements were conducted at points located at the edge of the cantilever excavation support system. The displacements of the excavation support observed over the period of three years demonstrated the pattern of steady growth over the first two months, followed by a gradual levelling out to a final plateau. The numerical analyses were conducted based on 3D FEM models. The numerical analysis of the problem comprise calculations of the global structural safety factor depending on the displacement of the chosen points in the lagging and conducted by means of the φ/c reduction procedure. The adopted graphical method of safety estimation is very conservative in the sense that it recognizes stability loss quite early, when one could further load the medium or weaken it by further strength reduction. The values of the Msf factor are relatively high. This is caused by the fact that the structure was designed for excavation twice as deep. Nevertheless, the structure is treated as a temporary one.

  14. Granular Flow and Dynamics of Lunar Simulants in Excavating Implements

    NASA Technical Reports Server (NTRS)

    Agui, Juan H.; Wilkinson, R. Allen

    2010-01-01

    The exploration of the lunar surface will rely on properly designed excavation equipment for surface preparations and for collection of lunar regolith in In-Situ Resource Utilization (ISRU) processes. Performance efficiency, i.e minimizing loading forces while maximizing material collection, and mass and volume reductions are major design goals. The NASA Glenn Research Center has embarked on an experimental program to determine the flow characteristics and dynamic forces produced by excavation operations using various excavator bucket designs. A new large scale soil bin facility, 2.27 m x 5.94 m x 0.76 m (nominally 8 ft. x 20 ft. x 27 in.) in size, capable of accommodating moderately large test implements was used for the simulations of lunar operations. The soil bin is filled with GRC-3simulant (a mixture of industrial sands and silt with a particle size distribution and the bulk mechanical (shear) strength representative of an average of lunar regolith from different regions) and uses motorized horizontal rails and a vertical actuator to drive the implement through the lunar simulant soil. A six-axis load cell and encoders provide well resolved measurements of the three dimensional forces and torques and motion of the bucket. In addition, simultaneous video allows for the analysis of the flow behavior and structure formation of the regolith during excavation. The data may be useful in anchoring soil mechanic models and to provide engineering data for design consideration.

  15. 43 CFR 10.3 - Intentional archaeological excavations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for obtaining such permits, see 25 CFR part 262 or contact the Deputy Commissioner of Indian Affairs... PROTECTION AND REPATRIATION REGULATIONS Human Remains, Funerary Objects, Sacred Objects, or Objects of... objects, sacred objects, or objects of cultural patrimony that are excavated intentionally from Federal...

  16. 43 CFR 10.3 - Intentional archaeological excavations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for obtaining such permits, see 25 CFR part 262 or contact the Deputy Commissioner of Indian Affairs... PROTECTION AND REPATRIATION REGULATIONS Human Remains, Funerary Objects, Sacred Objects, or Objects of... objects, sacred objects, or objects of cultural patrimony that are excavated intentionally from Federal...

  17. 6. VIEW WEST, INTERIOR CANAL WALL, FLOOR FULLY EXCAVATED (Original ...

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

    6. VIEW WEST, INTERIOR CANAL WALL, FLOOR FULLY EXCAVATED (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  18. 8. DETAIL OF WEST WALL, FLOOR FULLY EXCAVATED, CROSS MEMBER ...

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

    8. DETAIL OF WEST WALL, FLOOR FULLY EXCAVATED, CROSS MEMBER (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  19. 7. DETAIL OF WEST WALL, FLOOR FULLY EXCAVATED, FIRST AND ...

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

    7. DETAIL OF WEST WALL, FLOOR FULLY EXCAVATED, FIRST AND SECOND LAYER OF PLANKS (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  20. 9. VIEW NORTH, EXCAVATED LOCK FROM WATER STREET (Numbers painted ...

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

    9. VIEW NORTH, EXCAVATED LOCK FROM WATER STREET (Numbers painted on stones for reconstruction purposes) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  1. 40. Photocopied August 1978. EXCAVATION IN THE FOREBAY, VIEW LOOKING ...

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

    40. Photocopied August 1978. EXCAVATION IN THE FOREBAY, VIEW LOOKING WEST, MARCH 31, 1899. THE EQUIPMENT USED IN THIS AREA WAS MAINLY MAN-OR HORSE-POWERED SINCE SOIL CONDITIONS HERE (NEAR THE RIVER) WERE TOO SOFT TO PERMIT HEAVY EQUIPMENT. (28) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  2. CUTS FOR MTR EXCAVATION ILLUSTRATE SEDIMENTARY MANTLE OF SOIL AND ...

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

    CUTS FOR MTR EXCAVATION ILLUSTRATE SEDIMENTARY MANTLE OF SOIL AND GRAVEL OVERLAYING LAVA ROCK FIFTY FEET BELOW. SAGEBRUSH HAS BEEN SCOURED FROM REST OF SITE. CAMERA PROBABLY FACES SOUTHWEST. INL NEGATIVE NO. 67. Unknown Photographer, 6/4/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  3. 30. DETAILED FRONTAL VIEW WEST OF EXCAVATION AT SUSPECTED MICA ...

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

    30. DETAILED FRONTAL VIEW WEST OF EXCAVATION AT SUSPECTED MICA PIT, SHOWING SOIL MIXED WITH MICA FLAKES AT REAR, AND DEEPER HOLE OF VIRGIN SOIL AT FRONT. - Vulcan Crucible Steel Company, Building No. 3, 100 First Street, Aliquippa, Beaver County, PA

  4. OEM unveil new ideas for shovels and excavators

    SciTech Connect

    Fiscor, S.

    2006-08-15

    From upgrades to new loading arrangements, vendors are looking at new ways to optimize the production process. The paper describes P & M equipment's new C series electric shovels equipped with the centurion system, Hitachi's super-sized excavator to Canadian oil sands, and Bucyrus and Siemens' engineer shovels. 3 figs., 1 photo.

  5. 10. View looking northwest at excavation into serpentine rock. Formwork ...

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

    10. View looking northwest at excavation into serpentine rock. Formwork at left is for pump room. Partially completed caisson is in foreground. Portion of Point Avisadero visible at right (12/17/42). Photographer unknown. - Hunters Point Naval Shipyard, Drydock No. 4, East terminus of Palou Avenue, San Francisco, San Francisco County, CA

  6. VIEW OF SOUTH GUN EMPLACEMENT. NOTE THE EXCAVATED EDGE OF ...

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

    VIEW OF SOUTH GUN EMPLACEMENT. NOTE THE EXCAVATED EDGE OF THE GUN BLOCK IN THE FOREGROUND. VIEW FACING NORTH - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, South Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  7. 17. Photocopy of photograph showing excavation of South Bank Substation ...

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

    17. Photocopy of photograph showing excavation of South Bank Substation site, 15 May 1939 (from the BPA Photo Archives, Portland, Oregon, Negative No. 345), LOOKING WEST - Bonneville Power Administration South Bank Substation, I-84, South of Bonneville Dam Powerhouse, Bonneville, Multnomah County, OR

  8. Development and demonstration of a telerobotic excavation system

    NASA Technical Reports Server (NTRS)

    Burks, Barry L.; Thompson, David H.; Killough, Stephen M.; Dinkins, Marion A.

    1994-01-01

    Oak Ridge National Laboratory is developing remote excavation technologies for the Department of Energy's Office (DOE) of Technology Development, Robotics Technology Development Program, and also for the Department of Defense (DOD) Project Manager for Ammunition Logistics. This work is being done to meet the need for remote excavation and removal of radioactive and contaminated buried waste at several DOE sites and unexploded ordnance at DOD sites. System requirements are based on the need to uncover and remove waste from burial sites in a way that does not cause unnecessary personnel exposure or additional environmental contamination. Goals for the current project are to demonstrate dexterous control of a backhoe with force feedback and to implement robotic operations that will improve productivity. The Telerobotic Small Emplacement Excavator is a prototype system that incorporates the needed robotic and telerobotic capabilities on a commercially available platform. The ability to add remote dexterous teleoperation and robotic operating modes is intended to be adaptable to other commercially available excavator systems.

  9. Diffusively anisotropic model for the deflagration-to-detonation transition

    NASA Astrophysics Data System (ADS)

    Kagan, Leonid; Sivashinsky, Gregory

    2014-03-01

    To elucidate the key mechanisms responsible for the transition from deflagrative to detonative combustion in smooth-walled channels, a reactive flow with anisotropic thermal and molecular diffusivities is considered. Setting the transverse diffusivities large compared to longitudinal diffusivities, the initially formed deflagration (despite no-slip boundary conditions) appears to be nearly planar and not accelerating. This, however, does not prevent its eventual abrupt transition to Chapman-Jouguet detonation.

  10. Method for attenuating seismic shock from detonating explosive in an in situ oil shale retort

    DOEpatents

    Studebaker, Irving G.; Hefelfinger, Richard

    1980-01-01

    In situ oil shale retorts are formed in formation containing oil shale by excavating at least one void in each retort site. Explosive is placed in a remaining portion of unfragmented formation within each retort site adjacent such a void, and such explosive is detonated in a single round for explosively expanding formation within the retort site toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in each retort. This produces a large explosion which generates seismic shock waves traveling outwardly from the blast site through the underground formation. Sensitive equipment which could be damaged by seismic shock traveling to it straight through unfragmented formation is shielded from such an explosion by placing such equipment in the shadow of a fragmented mass in an in situ retort formed prior to the explosion. The fragmented mass attenuates the velocity and magnitude of seismic shock waves traveling toward such sensitive equipment prior to the shock wave reaching the vicinity of such equipment.

  11. Steady 2d Detonations and the DSD Theory

    NASA Astrophysics Data System (ADS)

    Lubyatinsky, Sergey N.

    2005-07-01

    The simplest Detonation Shock Dynamics (DSD) theory assumes that the detonation normal velocity D is determined by the total front curvature k and that the edge angle, the angle between the normal to the front and the explosive edge, has a unique value for each explosive and confinement material combination. This model has been used to derive the ordinary differential equations describing steady 2D detonation front shapes in slab, cylinder and rib geometries. It was found that one solution (a steady detonation front shape) corresponds to several combinations of the confinement material and the defining charge dimension (slab thickness, cylinder radius, or inner rib radius). Comparing experimental data for these combinations and analyzing the shape difference at the edge provide valuable information on the D(k) relation at low D corresponding to forced detonation regimes. The analysis of the experimental data on IHE ribs detonation indicates that as D decreases k tends to a limit of about 0.05 1/mm, i.e., of the order of reciprocal critical diameter. This revises the present view of the D(k) relation making the DSD theory consistent with the experimentally observed critical diameter.

  12. Detonation Properties of Nitromethane, Deuterated Nitromethane and Bromonitromethane

    NASA Astrophysics Data System (ADS)

    Sheffield, Stephen A.; Davis, Lloyd L.; Engelke, Ray

    1999-06-01

    Nitromethane (CH_3NO_2)(NM) is an important explosive material in terms of understanding the chemistry and physics of initiation and detonation because it is one of the more simple explosive materials and is a liquid. We have been investigating the effects on its properties of replacing one of the hydrogen atoms with bromine (BrNM) and all the hydrogen atoms with deuterium (DNM). The French have indicated that the detonation failure diameter of DNM in glass more than doubles when compared to that of NM.(S. Courtecuisse, F. Cansell, D. Fabre, and J. P. Petitet, J. Chem. Phys., 108) (27) 1998. We have measured detonation velocity, critical diameter in brass, and the diameter effect curves for NM, BrNM, and DNM in brass. In addition, detonation wave profiles were obtained using VISAR to record the interface particle velocity between the detonating liquids and a polymethyl methacrylate (PMMA) window. DNM has a larger critical diameter in brass than both NM and BrNM. Its detonation velocity is lower than NM but higher than BrNM.

  13. Detonation cell widths in hydrogen-air-diluent mixtures

    SciTech Connect

    Stamps, D.W.

    1990-01-01

    In this paper I report on the influence of steam and carbon dioxide on the detonability of hydrogen-air mixtures. Data were obtained on the detonation cell width in a heated detonation tube that is 0.43 m in diameter and 13.1 m long. The detonation cell widths were correlated using a characteristic length calculated from a chemical kinetic model. The addition of either diluent to a hydrogen-air mixture increased the cell width for all equivalence ratios. For equal diluent concentrations, however, carbon dioxide not only yielded larger increases in the cell width than steam, but its efficacy relative to steam was predicted to increase with increasing concentration. The range of detonable hydrogen concentrations in a hydrogen-air mixture initially at 1 atm pressure was found to be between 11.6 percent and 74.9 percent for mixtures at 20{degree}C and 9.4 percent and 76.9 percent for mixtures at 100{degree}C. The detonation limit was between 38.8 percent and 40.5 percent steam for a stoichiometric hydrogen-air-steam mixture initially at 100{degree}C and 1 atm. 10 refs., 4 figs., 1 tab.

  14. Numerical simulation of Mach reflection of cellular detonations

    NASA Astrophysics Data System (ADS)

    Li, J.; Lee, J. H. S.

    2016-07-01

    The Mach reflection of cellular detonation waves on a wedge is investigated numerically in an attempt to elucidate the effect of cellular instabilities on Mach reflection, the dependence of self-similarity on the thickness of a detonation wave, and the initial development of the Mach stem near the wedge apex. A two-step chain-branching reaction model is used to give a thermally neutral induction zone followed by a chemical reaction zone for the detonation wave. A sufficiently large distance of travel of the Mach stem is computed to observe the asymptotic behavior in the far field. Depending on the scale at which the Mach reflection process occurs, it is found that the Mach reflection of a cellular detonation behaves essentially in the same way as a planar ZND detonation wave. The cellular instabilities, however, cause the triple-point trajectory to fluctuate. The fluctuations are due to interactions of the triple point of the Mach stem with the transverse waves of cellular instabilities. In the vicinity of the wedge apex, the Mach reflection is found to be self-similar and corresponds to that of a shock wave of the same strength, since the Mach stem is highly overdriven initially. In the far field, the triple-point trajectory approaches a straight line, indicating that the Mach reflection becomes self-similar asymptotically. The distance of the approach to self-similarity is found to decrease rapidly with decreasing thickness of the detonation front.

  15. Minimum tube diameters for steady propagation of gaseous detonations

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Ng, H. D.; Lee, J. H. S.

    2014-07-01

    Recent experimental results on detonation limits are reported in this paper. A parametric study was carried out to determine the minimum tube diameters for steady detonation propagation in five different hydrocarbon fuel-oxygen combustible mixtures and in five polycarbonate test tube diameters ranging from 50.8 mm down to a small scale of 1.5 mm. The wave propagation in the tube was monitored by optical fibers. By decreasing the initial pressure, hence the sensitivity of the mixture, the onset of limits is indicated by an abrupt drop in the steady detonation velocity after a short distance of travel. From the measured wave velocities inside the test tube, the critical pressure corresponding to the limit and the minimum tube diameters for the propagation of the detonation can be obtained. The present experimental results are in good agreement with previous studies and show that the measured minimum tube diameters can be reasonably estimated on the basis of the /3 rule over a wide range of conditions, where is the detonation cell size. These new data shall be useful for safety assessment in process industries and in developing and validating models for detonation limits.

  16. Numerical investigations on reignition behavior of detonation diffraction

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Han, Wen-Hu; Bi, Yong; Ding, Jian-Xu

    2016-02-01

    In this paper, by adopting a fifth-order weighted essentially non-oscillatory (WENO) scheme with a third-order TVD Runge-Kutta time stepping method for two-dimensional reactive Euler equations, a parallel code is developed, and reignition behavior after a self-sustaining detonation from the tube into free space filled with H2/O2 mixtures is investigated. The numerical results show that the initial pressure has a great influence on the detonation cellular width, and that as the initial pressure increases, the cellular width gradually decreases and the cellular shape changes from irregular structure to regular structure, demonstrating the detonation instability to stability transition. When the initial pressure is larger than 1.2 atm, the detonation wave expands over the edge of the splitter plate, reignition can come into being because enough transverse waves collide with each other at the leading edge of the expanding front. When the initial pressure is 1.2 atm, hot spots appear on the front, and ignite the combustible gas near the hot spots after detonation diffraction. When the initial pressure is 1.0 atm, reignition fails. These findings hint that a critical initial pressure exists between 1.0-1.2 atm for direct reignition after detonation diffraction.

  17. Non ideal detonation of emulsion explosives mixed with metal particles

    NASA Astrophysics Data System (ADS)

    Mendes, R.; Ribeiro, J.; Plaksin, I.; Campos, J.

    2011-06-01

    The detonation of ammonium nitrate based compositions like emulsion explosives (EX) mixed with metal particles has been investigated experimentally. Aluminium powder with a mean particle size of 10 μm was used, and the mass concentration of aluminum on the explosive charge was ranged from 0 to 30%. The values of the detonation velocity, the pressure attenuation - P(x) - of detonation front amplitude in a standard PMMA monitor and manganin gauges pressure-time histories are shown as a function of the explosive charge porosity and specific mass. All these parameters except the pressure-times histories have been evaluated using the multi fiber optical probe (MFOP) method which is based on the use of an optical fiber strip, with 64 independent optical fibers. The MFOP allow a quasi continuous evaluation of the detonation wave run propagation and the assessment to spatial resolved measurements of the shock wave induced in the PMMA barrier which in turns allows a detailed characterization of the detonation reaction zone structure. Results of that characterization process are presented and discussed for aluminized and non aluminized EX. Moreover, the effect of the mass concentration of the sensitizing agent (hollow glass micro-balloons) on the non monotonic detonation velocity variation, for EX, will be discussed.

  18. Detonation performance of high-dense BTF charges

    NASA Astrophysics Data System (ADS)

    Dolgoborodov, Alexander; Brazhnikov, Michael; Makhov, Michael; Gubin, Sergey; Maklasova, Irina

    2013-06-01

    New experimental data on detonation wave parameters and explosive performance for benzotrifuroxan (BTF) are presented. Optical pyrometry was applied in order to measure the temperature and pressure of BTF detonation products. Chapman-Jouguet pressure and temperature were obtained as following: 33.8 GPa and 3990 K; 34.5 GPa and 4170 K (initial charge densities 1.82 and 1.84 g/cc respectively), the polytropic exponent was estimated as 2.8. The heat of explosion and acceleration ability were measured also. The results of calorimetric measurements performed in bomb calorimeter indicate that BTF slightly surpasses HMX in the heat of explosion. However BTF is inferior to HMX in the acceleration ability, measured by the method of copper casing expansion. It is also considered the hypothesis of formation of nanocarbon particles in detonation products directly behind the detonation front and influence of this processes on the temperature-time history in detonation products. The results of calculations with in view of formation of liquid nanocarbon in products of a detonation also are presented.

  19. Acceleration of solid particles by gaseous detonation products

    SciTech Connect

    Gavrilenko, T.P.; Grigoriev, V.V.; Zhdan, S.A.; Nikolaev, Y.A.; Boiko, V.M.; Papyrin, A.N.

    1986-11-01

    This investigation is concerned with a theoretical and experimental study of acceleration dynamics of spherically inert solid particles (100 ..mu..m nominal diameter) in flows of gaseous detonation products. The experiments were conducted in a detonation channel 1.5 m long with a 20 x 20 mm/sup 2/ cross section and one open end. Particle motion was observed with the method of multiexposure photographic recording and a laser stroboscopic light source. The character of velocity variation of individual particles inside and outside of the channel was investigated for different initial positions of particles. Under certain conditions the accelerated particles are destroyed. A mathematical model based on two-phase multivelocity continuum mechanics has been formulated to describe the detonation wave propagation, outflow of detonation products from the channel, and interaction between particles and a nonstationary flow of detonation products. The model includes chemical equilibrium of detonation products, particle acceleration, heat exchange between phases and channel walls, particle melting, and fragmentation of droplets if the Weber number exceeds some critical value. Particle destruction has been correlated with the initial position, diameter, and physical properties of particles. Comparison of computer and experimental results shows that the model satisfactorily describes acceleration, heating, and fragmentation of particles.

  20. Radiopaque Tagging Masks Caries Lesions following Incomplete Excavation in vitro.

    PubMed

    Schwendicke, F; Meyer-Lueckel, H; Schulz, M; Dörfer, C E; Paris, S

    2014-06-01

    One-step incomplete excavation seals caries-affected dentin under a restoration and appears to be advantageous in the treatment of deep lesions. However, it is impossible to discriminate radiographically between intentionally left, arrested lesions and overlooked or active lesions. This diagnostic uncertainty decreases the acceptance of minimally invasive excavation and might lead to unnecessary re-treatment of incompletely excavated teeth. Radiopaque tagging of sealed lesions might mask arrested lesions and assist in discrimination from progressing lesions. Therefore, we microradiographically screened 4 substances (SnCl2, AgNO3, CsF, CsCH3COO) for their effect on artificial lesions. Since water-dissolved tin chloride (SnCl2×Aq) was found to stably mask artificial lesions, we then investigated its radiographic effects on progressing lesions. Natural lesions were incompletely excavated and radiopaque tagging performed. Grey-value differences (△GV) between sound and carious dentin were determined and radiographs assessed by 20 dentists. While radiographic effects of SnCl2×Aq were stable for non-progressing lesions, they significantly decreased during a second demineralization (p < .001, t test). For natural lesions, tagging with SnCl2×Aq significantly reduced △GV (p < .001, Wilcoxon). Tagged lesions were detected significantly less often than untagged lesions (p < .001). SnCl2×Aq was suitable to mask caries-affected dentin and discriminate between arrested and progressing lesions in vitro. Radiopaque tagging could resolve diagnostic uncertainties associated with incomplete excavation. PMID:24718110

  1. A small-scale experiment using microwave interferometry to investigate detonation and shock-to-detonation transition in pressed TATB

    NASA Astrophysics Data System (ADS)

    Renslow, Peter John

    A small-scale characterization test utilizing microwave interferometry was developed to dynamically measure detonation and run to detonation distance in explosives. The technique was demonstrated by conducting two experimental series on the well-characterized explosive triaminotrinitrobenzene (TATB). In the first experiment series, the detonation velocity was observed at varying porosity. The velocity during TATB detonation matched well with predictions made using CHEETAH and an empirical relation from the Los Alamos National Laboratory (LANL). The microwave interferometer also captured unsteady propagation of the reaction when a low density charge was near the failure diameter. In the second experiment series, Pop-plots were produced using data obtained from shock initiation of the TATB through a polymethyl methacrylate (PMMA) attenuator. The results compared well to wedge test data from LANL despite the microwave interferometer test being of substantially smaller scale. The results showed the test method is attractive for rapid characterization of new and improvised explosive materials.

  2. Stability of Chapman Jouguet detonations for a stiffened-gas model of condensed-phase explosives

    NASA Astrophysics Data System (ADS)

    Short, Mark; Bdzil, John B.; Anguelova, Iana I.

    2006-04-01

    The analysis of the linear stability of a planar Chapman Jouguet detonation wave is reformulated for an arbitrary caloric (incomplete) equation of state in an attempt to better represent the stability properties of detonations in condensed-phase explosives. Calculations are performed on a ‘stiffened-gas’ equation of state which allows us to prescribe a finite detonation Mach number while simultaneously allowing for a detonation shock pressure that is substantially larger than the ambient pressure. We show that the effect of increasing the ambient sound speed in the material, for a given detonation speed, has a stabilizing effect on the detonation. We also show that the presence of the slow reaction stage, a feature of detonations in certain types of energetic materials, where the detonation structure is characterized by a fast reaction stage behind the detonation shock followed by a slow reaction stage, tends to have a destabilizing effect.

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  5. Gaseous detonation initiation and stabilization by hypervelocity projectiles

    NASA Astrophysics Data System (ADS)

    Kaneshige, Michael Jiro

    An experimental investigation of gaseous detonations initiated and stabilized by high-speed spherical projectiles has been carried out. Detonation initiation by projectiles is closely related to propulsion concepts such as the ram accelerator and the oblique detonation wave engine, in which, theoretically, rapid combustion occurs in detonation waves stabilized on solid objects. The criteria for initiation and stabilization by projectiles are also related to other initiation and propagation criteria such as blast initiation and failure of diffracting detonations. Experimental data of this type are useful for identifying relevant assumptions and important processes, and for providing validation for computational and analytical models. Experiments were performed in the Caltech T5 shock tunnel laboratory. T5 was used in a shock-compression light gas gun mode, with 25.4-mm diameter nylon spheres and velocities around 2300 m/s. Gaseous mixtures studied included 2H2+O2+βN2 (1 >= β >= 13.76), C2H4+3O2+5N2, and C2H 2+2.5O2+9.4N2 at initial pressures of 0.08-2.56 bar. Flow visualization results obtained by differential interferometry, shadowgraphy, and intensified CCD imaging were augmented by wall pressure records. A wide variety of results were observed, including non- detonative shock-induced combustion, unstably initiated detonations, stabilized prompt initiations, and stabilized delayed initiations. These results can be roughly correlated in terms of the ratio of projectile velocity to mixture Chapman-Jouguet detonation speed, and the ratio of projectile diameter to detonation cell size or reaction zone thickness, although the effects of confinement and unsteadiness complicate this categorization. Two basic approaches to modeling the results have been attempted. In the first, a global model for initiation is based on an existing blast-initiation model using the hypersonic blast-wave analogy. This model is simple, and roughly predicts the experimental results, but

  6. Predicting propagation limits of laser-supported detonation by Hugoniot analysis

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Ofosu, Joseph A.; Komurasaki, Kimiya; Koizumi, Hiroyuki

    2015-01-01

    Termination conditions of a laser-supported detonation (LSD) wave were investigated using control volume analysis with a Shimada-Hugoniot curve and a Rayleigh line. Because the geometric configurations strongly affect the termination condition, a rectangular tube was used to create the quasi-one-dimensional configuration. The LSD wave propagation velocity and the pressure behind LSD were measured. Results reveal that the detonation states during detonation and at the propagation limit are overdriven detonation and Chapman-Jouguet detonation, respectively. The termination condition is the minimum velocity criterion for the possible detonation solution. Results were verified using pressure measurements of the stagnation pressure behind the LSD wave.

  7. A Review of Lunar Regolith Excavation Robotic Device Prototypes

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.; Van Susante, Paul J.

    2011-01-01

    The excavation of lunar regolith is desirable for use as a feedstock for oxygen production processes as well as civil engineering purposes and for the fabrication of parts and structures. This is known as In-Situ Resource Utilization (ISRU). More recently, there has been mounting evidence that water ice exists at the poles of the Moon, buried in the regolith where thermally stable conditions exist. This means that regolith excavation will be required to mine the water ice which is believed to be. mixed in with the regolith, or bonded to it. The mined water ice can then be electrolyzed to produce hydrogen and oxygen propellants which could form the basis of a cis-lunar transportation system using in-situ derived propellants. In 2007, the National Aeronautics & Space Administration (NASA) sponsored a Lunar Regolith Excavation Competition as part of its Centennial Challenges program, The competition was not won and it was held again in 2008 and 2009, when it was won by a university team. A $500,000 prize was awarded to the winning team by NASA. In 2010, NASA continued the competition as a spinoff of the Centennial Challenges, which is restricted to university participation only. This competition is known as the "Lunabotics Mining Competition" and is hosted by NASA at Kennedy Space Center. Twenty three American university teams competed in the 2010 Lunabotics Mining Competition. The competition was held again in May 2011 with over 60 teams registered, including international participation. The competition will be held again in May 2012 at Kennedy Space Center in Florida. . This paper contains a thorough review of the various regolith eX,cavation robotic device prototypes that competed in these NASA competitions, and will. classify the machines and their methods of excavation to document the variety of ideas that were spawned and built to compete at these events. It is hoped that documentation of these robots will serve to help future robotic excavation designers and

  8. Numerical simulation of detonation failure in nitromethane

    SciTech Connect

    Kipp, M.E.; Nunziato, J.W.

    1981-01-01

    Detonation failure in the homogeneous liquid explosive nitromethane has been observed experimentally in a wide variety of confining geometries. However, numerical simulation of these failure situations with a wave propagation code has been essentially non-existent due to the large differences between the critical diameter and the length of the reaction zone - characteristic dimensions which differ by about two orders of magnitude. This inability to spatially resolve both the reaction zone and geometries of significant size has led us to propose a new numerical technique, based on the stability criterion for rate-type material models, in which only temporal resolution of the reaction zone is required. Using an improved model for nitromethane, we have carried out a series of two-dimensional calculations which illustrate the utility of the present approach in predicting a wide range of experimental observations. Of particular computational significance is the removal of the difficulty requiring spatial resolution of the reaction zone, so that problems of practical size can be analyzed with existing computer capabilities.

  9. Equations of state for detonation problems

    SciTech Connect

    Davis, W.C.

    1997-08-01

    The words `Equation of State` have usually been used in the detonation physics community to mean whatever information about the materials involved that would make it possible to solve the problem at hand. As the problems have become more complicated and the computer simulation more detailed, better and better equations of state have been developed and used. Still, most equations of state have been limited to use in solving the hydrodynamic equations for an inviscid, non-heat-conducting, non-radiating, non-reacting fluid. All the information in these equations of state is about the mechanical properties. There is no information about the temperature, entropy, or specific heat. The focus of this paper is not on providing a new equation of state that will allow the solution of all problems, but to discuss the restrictions on equations of state, and the effect of those restrictions on their properties. Later, when there are more data, it will be time to search for the best equations of state for all the various problems.

  10. Nonideal detonation regimes in low density explosives

    NASA Astrophysics Data System (ADS)

    Ershov, A. P.; Kashkarov, A. O.; Pruuel, E. R.; Satonkina, N. P.; Sil'vestrov, V. V.; Yunoshev, A. S.; Plastinin, A. V.

    2016-02-01

    Measurements using Velocity Interferometer System for Any Reflector (VISAR) were performed for three high explosives at densities slightly above the natural loose-packed densities. The velocity histories at the explosive/window interface demonstrate that the grain size of the explosives plays an important role. Fine-grained materials produced rather smooth records with reduced von Neumann spike amplitudes. For commercial coarse-grained specimens, the chemical spike (if detectable) was more pronounced. This difference can be explained as a manifestation of partial burn up. In fine-grained explosives, which are more sensitive, the reaction can proceed partly within the compression front, which leads to a lower initial shock amplitude. The reaction zone was shorter in fine-grained materials because of higher density of hot spots. The noise level was generally higher for the coarse-grained explosives, which is a natural stochastic effect of the highly non-uniform flow of the heterogeneous medium. These results correlate with our previous data of electrical conductivity diagnostics. Instead of the classical Zel'dovich-von Neumann-Döring profiles, violent oscillations around the Chapman-Jouguet level were observed in about half of the shots using coarse-grained materials. We suggest that these unusual records may point to a different detonation wave propagation mechanism.

  11. Deflagration to detonation experiments in granular HMX

    SciTech Connect

    Burnside, N.J.; Son, S.F.; Asay, B.W.; Dickson, P.M.

    1998-03-01

    In this paper the authors report on continuing work involving a series of deflagration-to-detonation transition (DDT) experiments in which they study the piston-initiated DDT of heavily confined granular cyclotetramethylenetetranitramine (HMX). These experiments were designed to he useful in model development and evaluation. A main focus of these experiments is the effect of density on the DDT event. Particle size distribution and morphology are carefully characterized. In this paper they present recent surface area analysis. Earlier studies demonstrated extensive fracturing and agglomeration in samples at densities as low as 75% TMD as evidenced by dramatic decreases in particle size distribution due to mild stimulus. This is qualitatively confirmed with SEM images and quantitatively studied with gas absorption surface area analysis. Also, in this paper they present initial results using a microwave interferometer technique. Dynamic calibration of the technique was performed, a 35 GHz signal is used to increase resolution, and the system has been designed to be inexpensive for repeated experiments. The distance to where deformation of the inner wall begins for various densities is reported. This result is compared with the microwave interferometer measurements.

  12. Shock initiation of detonation in nitromethane

    NASA Astrophysics Data System (ADS)

    Leal, B.; Presles, H. N.; Baudin, G.

    1998-07-01

    The processes involved in the initiation of nitromethane (NM) have been the subject of many experiments and theoretical studies. These studies generally support the classical homogeneous model though some details of the buildup process are still controversial. In order to clarify these points, we have performed plate impact experiments to study the initiation of NM under conditions of steady one dimensional strain, for shock pressures ranging from 8.5 to 12 GPa. A six wavelength optical pyrometer, with 3 ns rise-time and a temperature range of 1500-6000 K, was used to determine the temperature during shock-to-detonation transition. A Fabry-Perot interferometer with a capacitor transducer and piezoelectric pins were also used to analyse the temperature profiles and to determine the sequence of events during the initiation process. According to our experimental results, it seems that, unlike Campbell et al. assumptions, the superdetonation does not start at the plate/NM interface, but at a run distance inside the NM depending on the shock level.

  13. Shock initiation of detonation in nitromethane.

    NASA Astrophysics Data System (ADS)

    Leal, Blandine; Presles, Henri-Noel; Baudin, Gerard

    1997-07-01

    The processes involved in the initiation of nitromethane (NM) have been the subject of many experiments and theoretical studies. These studies generally support the classical homogeneous model though some details of the buildup process are still controversial. In order to clarify these points, we have performed plate impact experiments to study the initiation of NM under conditions of steady one dimensionnal strain, for shock pressures ranging from 9 to 12GPa. A six wavelength optical pyrometer, with 3ns rise-time and a temperature range of 1500-6000K, was used to determine the temperature during shock-to-detonation transition. A Fabry-Perot interferometer with a capacitor transducer and piezoelectric pins were also used to analyse the temperature profiles and to determine the sequence of events during the initiation process. The experimental results showed that, unlike Campbell assumptions, the superdetonation does not start at the NM front surface, but at a run distance inside the NM depending on the shock level.

  14. Efficiency of Pulsed Detonation Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Cannon, Jacob E.; Alkam, Mohammad; Butler, P. Barry

    2008-12-01

    Pulsed detonation thermal spray coating is used to enhance the material properties at the surface of an object. The present research implements computational fluid dynamic modeling to identify the efficiency of energy and mass delivered to potential target locations. Six cases of a hydrogen-air mixture are used to investigate the gas flow from the instant of ignition to the instant of flow reversal at the tube exit. Flow monitors are included in the model to represent potential target locations. These monitors are placed at different axial locations in order to record mass flow rate and the flow rate of enthalpy over time. The results indicate that there exists a quasi-steady jet that is efficient and predictable in delivery of energy and mass from the tube exit to potential target locations positioned on the centerline. The duration of the quasi-steady jet is dependent on the fraction of combustible gas (i.e., % fill). Much of the initial energy and mass delivered from the jet avoids the flow monitors. This is found to be related to the evolution of the jet behind the blast wave where energy is lost in expansion and vorticity production. It is also found that nearly 11-18% of the available energy and 20-23% of the available mass remains in the tube after flow reversal.

  15. 43 CFR 15.3 - Dredging, filling, excavating and building activities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating,...

  16. 43 CFR 15.3 - Dredging, filling, excavating and building activities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or filling operations of any kind...

  17. 43 CFR 15.3 - Dredging, filling, excavating and building activities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating,...

  18. 43 CFR 15.3 - Dredging, filling, excavating and building activities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating,...

  19. 43 CFR 15.3 - Dredging, filling, excavating and building activities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating,...

  20. Nuclear winter - Physics and physical mechanisms

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Toon, O. B.; Pollack, J. B.; Ackerman, T. P.; Sagan, C.

    1991-01-01

    The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples.