WorldWideScience

Sample records for benign stab detonators

  1. Environmentally Benign Stab Detonators

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Environmentally Benign Stab Detonators

    Science.gov (United States)

    2006-07-11

    a mixture of lead azide, lead styphnate , barium nitrate, antimony sulfides, and tetracene) mJ millijoule (10–3 J) FINAL REPORT PP...initiating mix (NOL-130) and transfer charge of current stab detonators contain hazardous materials such as lead azide, lead styphnate , and barium nitrate...tetracene) and heavy metal constituents (e.g., lead styphnate , lead azide, barium nitrate, and antimony sulfides) present in the NOL-130 initiating

  3. Environmentally Benign Stab Detonators

    Energy Technology Data Exchange (ETDEWEB)

    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

  4. Environmentally Benign Stab Detonators

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Barbee, T; Simpson, R; Satcher, J; Walton, C

    2003-12-15

    This effort attempts to demonstrate that environmentally acceptable energetic sol-gel 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 metal multilayer and sol-gel to be generic technologies applicable to a wide range of devices, especially in small caliber ammunition and sub-munitions. We will replace the NOL-130 mixture with a nanocomposite that consists of a mechanically robust energetic multilayer foil that has been coated with a sol-gel energetic material. The exothermic reactions are activated in this nanocomposite are the transformation of the multilayer material to its respective intermetallic alloy and the thermite reaction, which is characterized by very high temperatures, a small pressure pulse, and hot particle ejection. The proposed materials and their reaction products consist of, but are not limited to aluminum, nickel, iron, aluminum oxide, titanium, iron oxide and boron. These materials have much more desirable environmental and health characteristics than the NOL-130 composition.

  5. Stab Sensitivity of Energetic Nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Barbee, T; Cervantes, O

    2006-05-22

    This work details the stab ignition, small-scale safety, and energy release characteristics of bimetallic Al/Ni(V) and Al/Monel energetic nanolaminate freestanding thin films. The influence of the engineered nanostructural features of the energetic multilayers is correlated with both stab initiation and small-scale energetic materials testing results. Structural parameters of the energetic thin films found to be important include the bi-layer period, total thickness of the film, and presence or absence of aluminum coating layers. In general the most sensitive nanolaminates were those that were relatively thick, possessed fine bi-layer periods, and were not coated. Energetic nanolaminates were tested for their stab sensitivity as freestanding continuous parts and as coarse powders. The stab sensitivity of mock M55 detonators loaded with energetic nanolaminate was found to depend strongly upon both the particle size of the material and the configuration of nanolaminate material, in the detonator cup. In these instances stab ignition was observed with input energies as low as 5 mJ for a coarse powder with an average particle dimension of 400 {micro}m. Selected experiments indicate that the reacting nanolaminate can be used to ignite other energetic materials such as sol-gel nanostructured thermite, and conventional thermite that was either coated onto the multilayer substrate or pressed on it. These results demonstrate that energetic nanolaminates can be tuned to have precise and controlled ignition thresholds and can initiate other energetic materials and therefore are viable candidates as lead-free impact initiated igniters or detonators.

  6. Stab resistant body armour

    OpenAIRE

    Horsfall, Ian

    2000-01-01

    There is now a widely accepted need for stab resistant body armour for the police in the UK. However, very little research has been done on knife resistant systems and the penetration mechanics of sharp projectiles are poorly understood. This thesis explores the general background to knife attack and defence with a particular emphasis on the penetration mechanics of edged weapons. The energy and velocity that can be achieved in stabbing actions has been determined for a numb...

  7. Primary stabbing headache.

    Science.gov (United States)

    Pareja, Juan A; Sjaastad, Ottar

    2010-01-01

    Primary stabbing headache is characterized by transient, cephalic ultrashort stabs of pain. It is a frequent complaint with a prevalence of 35.2%, a female preponderance, and a mean age of onset of 28 years (Vågå study). Attacks are generally characterized by moderate to severe, jabbing or stabbing pain, lasting from a fraction of a second to 3s. Attack frequency is generally low, with one or a few attacks per day. The paroxysms generally occur spontaneously, during daytime. Most patients exhibit a sporadic pattern, with an erratic, unpredictable alternation between symptomatic and non-symptomatic periods. Paroxysms are almost invariably unilateral. Temporal and fronto-ocular areas are most frequently affected. Attacks tend to move from one area to another, in either the same or the opposite hemicranium. Jabs may be accompanied by a shock-like feeling and even by head movement - "jolts" -or vocalization. On rare occasions, conjunctival hemorrhage and monocular vision loss have been described as associated features. Primary stabbing headache may concur, synchronously or independently, with other primary headaches. In contrast to what is the case in adults, in childhood it is not usually associated with other headaches. Treatment is rarely necessary. Indomethacin, 75-150 mg daily, may seem to be of some avail. Celecoxib, nifedipine, melatonin, and gabapentin have been reported to be effective in isolated cases and small series of patients. The drug studies need corroboration.

  8. Primary and secondary stabbing headache.

    Science.gov (United States)

    Robbins, Matthew S; Evans, Randolph W

    2015-04-01

    Eight out of the 33 cases of primary stabbing headache seen in a general neurology clinic (40% have headache as their chief complaint) in the last 3.5 years are presented. The epidemiology, association with other primary headache disorders, secondary associations, testing, and treatment of primary stabbing headache are reviewed.

  9. Biomechanics of knife stab attacks.

    Science.gov (United States)

    Chadwick, E K; Nicol, A C; Lane, J V; Gray, T G

    1999-10-25

    Equipment, materials and methods for the measurement of the biomechanical parameters governing knife stab attacks have been developed and data have been presented that are relevant to the improvement of standards for the testing of stab-resistant materials. A six-camera Vicon motion analysis system was used to measure velocity, and derive energy and momentum during the approach phase of the attack and a specially developed force-measuring knife was used to measure three-dimensional forces and torque during the impact phase. The body segments associated with the knife were modelled as a series of rigid segments: trunk, upper arm, forearm and hand. The velocities of these segments, together with knowledge of the mass distribution from biomechanical tables, allowed the calculation of the individual segment energy and momentum values. The instrumented knife measured four components of load: axial force (along the length of the blade), cutting force (parallel to the breadth of the blade), lateral force (across the blade) and torque (twisting action) using foil strain gauges. Twenty volunteers were asked to stab a target with near maximal effort. Three styles of stab were used: a short thrust forward, a horizontal style sweep around the body and an overhand stab. These styles were chosen based on reported incidents, providing more realistic data than had previously existed. The 95th percentile values for axial force and energy were 1885 N and 69 J, respectively. The ability of current test methods to reproduce the mechanical parameters measured in human stab attacks has been assessed. It was found that current test methods could reproduce the range of energy and force values measured in the human stab attacks, although the simulation was not accurate in some respects. Non-axial force and torque values were also found to be significant in the human tests, but these are not reproduced in the standard mechanical tests.

  10. [Stab wounds in emergency department].

    Science.gov (United States)

    Bège, T; Berdah, S V; Brunet, C

    2013-12-01

    Stab wounds represent the most common cause of penetrating wounds, occurring mainly in case of aggression or suicide attempt. Clinical severity depends on the superficial or penetrating aspect of the wound, its location and damaged organs. Medical management must be known because the vital risk is involved in penetrating wounds. Hemodynamically unstable patients should be operated without delay after performing a chest X-ray and ultrasound Focus assisted sonography for trauma (FAST) to guide the surgery. In the stable patients, the general clinical examination, exploration of the wound and medical imaging detect injuries requiring surgical management. Stab penetrating wounds require close and rapid collaboration between medical teams, tailored to the institution's resources.

  11. Ultrasonic Weld Sealing of M55 Stab Detonators

    Science.gov (United States)

    1981-01-01

    barium nitrate, and graphite Lead styphnate , tetracene, barium nitrate NOL-130 5 1. Elimination of the lacquer application with its attendant...chlorate FFFFG Magnesium and barium peroxide Boron, lead dioxide, and Viton A AIA (ferric oxide, zirconium) Potassium chlorate, sulfur, and dyes...Tungsten, barium perchlorate, and ammon- ium perchlorate Manganese, barium chromate, and lead chromate Magnesium, sodium nitrate, organic binder 75

  12. Nonpropagation Test Program for M55 Stab Detonators

    Science.gov (United States)

    1982-07-01

    carton, and five cartons per wooden bux. MRC provided the dial indexing integrity test fixture and tube-to-dial inter- face adapter. A Deltron Fluid ...dial nest Integrity test setup 23 Solenoid valve •- Skinner M/odel EG7 •-Deltron fluid products Office 0.79 a•m -’•"(0.031in- metering valve 0-23684...Radford, VA 24141 Commander Sunflower Army munition Plant ATTN: SARSU-S Lawrence, KS 66044 Commander Volunteer Army Amnition Plant ATTN: SARVO-S

  13. Detonation control

    Science.gov (United States)

    Mace, Jonathan L.; Seitz, Gerald J.; Bronisz, Lawrence E.

    2016-10-25

    Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.

  14. An unusual stab wound to the buttock

    Directory of Open Access Journals (Sweden)

    Ashraf F Hefny

    2013-01-01

    Full Text Available Stab wounds to the buttock are uncommon injuries that are rarely seen in surgical civilian practice. Although, the wound appears trivial, it may cause major life-threatening visceral and vascular injuries. Failure to detect these injuries may lead to serious morbidity and mortality. Herein, we report a patient with a single gluteal stab wound, which was initially sutured and treated conservatively. Two days later, patient developed fever, lower abdominal pain and tenderness with leakage of fecal material from the wound. Exploratory laparotomy revealed an extraperitoneal rectal perforation for which a Hartmann′s procedure was performed. Computed tomography scanning is recommended as a diagnostic tool for stable patients having buttock stab wounds. Diverging colostomy is the standard surgical procedure for extraperitonal rectal injuries that cannot be properly visualized and repaired during a laparotomy. More evidence is needed to assess the fecal non-diversion approach in the treatment of these patients.

  15. Penetrating Stab Wound of the Right Ventricle

    Directory of Open Access Journals (Sweden)

    Onursal Buğra

    2010-04-01

    Full Text Available 18 years old male patient was admitted to our emergency unit with a penetrating stab wound to the right ventricle. A stab wound to the right ventricle was found to be 3 cm in diameter. The bleeding was controlled by insertion of a Foley catheter and inflation of the balloon. The stab wound had transected distal acute marginal side ofthe right coronary artery. A successful repair was performed with the use of a foley catheter and application of the Medtronic Octopus Tissue Stabilization System. The wound was closed with pledgeted mattress sutures. The distal acute marginal side of the right coronary artery was ligated. In this presentation, the surgical intervention method was reported and followed by a discussion of emergency surgical procedures of the heart.

  16. A Case Report on Stab Injury

    Directory of Open Access Journals (Sweden)

    Asma Begum

    2014-01-01

    Full Text Available Stabbing is the most common method of homicide in developing countries like Bangladesh, due to poverty, over population, joblessness, political unrest, etc. The reported case is of a 27 years old man stabbed on the front of the left thigh, a relatively unusual site by a sharp pointed knife by some snatchers while sitting on a rickshaw. On medicolegal point of view the injury was homicidal in nature to run away without having a motive to kill the person. The site was easily approachable for the snatchers. We need to create awareness among general population about the circumstances and probable mishaps that can happen unexpectedly.

  17. 17th STAB/DGLR Symposium

    CERN Document Server

    Heller, Gerd; Kreplin, Hans-Peter; Nitsche, Wolfgang; Peltzer, Inken

    2013-01-01

    This volume contains the contributions to the 17th Symposium of STAB (German Aerospace Aerodynamics Association). STAB includes German scientists and engineers from universities, research establishments and industry doing research and project work in numerical and experimental fluid mechanics and aerodynamics, mainly for aerospace but also for other applications. Many of the contributions collected in this book present results from national and European Community sponsored projects. This volume gives a broad overview of the ongoing work in this field in Germany and spans a wide range of topics: airplane aerodynamics, multidisciplinary optimization and new configurations, hypersonic flows and aerothermodynamics, flow control (drag reduction and laminar flow control), rotorcraft aerodynamics, aeroelasticity and structural dynamics, numerical simulation, experimental simulation and test techniques, aeroacoustics as well as the new fields of biomedical flows, convective flows, aerodynamics and acoustics of high-s...

  18. 18th STAB/DGLR Symposium

    CERN Document Server

    Heller, Gerd; Krämer, Ewald; Kreplin, Hans-Peter; Nitsche, Wolfgang; Rist, Ulrich

    2014-01-01

    This book presents contributions to the 18th biannual symposium of the German Aerospace Aerodynamics Association (STAB). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. By addressing a number of essential research subjects, together with their related physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field, as well as its main challenges and new directions. Current work on e.g. high aspect-ratio and low aspect-ratio wings, bluff bodies, laminar flow control and transition, active flow control, hypersonic flows, aeroelasticity, aeroacoustics and biofluid mechanics is exhaustively discussed here.  .

  19. 11th AG STAB/DGLR Symposium

    CERN Document Server

    Heinemann, Hans-Joachim; Hilbig, Reinhard

    1999-01-01

    This volume contains the papers of the 11th Symposium of the AG STAB (German Aerospace Aerodynamics Association). In this association those scientists and engineers from universities, research-establishments and industry are involved, who are doing research and project work in numerical and experimental fluid mechanics and aerodynamics for aerospace and other applications. Many of the contributions are giving results from the "Luftfahrtforschungsprogramm der Bundesregierung (German Aeronautical Research Programme). Some of the papers report on work sponsored by the Deutsche Forschungsgemeinschaft, DFG, which also was presented at the symposium. The volume gives a broad overview over the ongoing work in this field in Germany.

  20. Standing detonation wave engine

    KAUST Repository

    Kasimov, Aslan

    2015-10-08

    A detonation engine can detonate a mixture of fuel and oxidizer within a cylindrical detonation region to produce work. The detonation engine can have a first and a second inlet having ends fluidly connected from tanks to the detonation engine. The first and second inlets can be aligned along a common axis. The inlets can be connected to nozzles and a separator can be positioned between the nozzles and along the common axis.

  1. Application of an ancient Chinese algorithm to stab performance of woven fabrics

    Directory of Open Access Journals (Sweden)

    Wang Ping

    2016-01-01

    Full Text Available Stab damage is a common failure mode for textile products, especially for the geotextiles and geotextile-related products which are widely used in the road, airport, pipeline, and so on. In this paper, an ancient Chinese algorithm is applied to predict the stab area and stab energy of woven fabrics under stabbing load according to the load-displacement performance of the single yarn. This research proposes a novel method to analyze the stab property of the textile products.

  2. The effect of fabric and stabbing variables on severance appearance.

    Science.gov (United States)

    Cowper, E J; Carr, D J; Horsfall, I; Fergusson, S M

    2015-04-01

    During a stabbing, apparel fabrics are usually damaged and may be penetrated. Despite numerous studies considering forces required to penetrate skin and human stabbing performance, none have systematically evaluated which variables affect severance appearance from a textile science perspective using a human stabbing participant assessment. Although the human performance aspects of stabbing attacks have been previously studied, there has been a bias towards male assailants. The effects of fabric elasticity and tension applied have been identified as major factors influencing the severance profile in the fabric resulting from a stab attack. However, previous studies have considered limited fabric types with little emphasis on the physical and mechanical textile properties. The purpose of the current research was to use a human participant study (male n=5; female n=5) to determine the effect of fabric extension (0%, 10%) on the severance profile. Fabric type (single jersey; 100% cotton; 93% cotton/7% elastane), age (not laundered; laundered 60 times) and knife type (carving, bread) were also considered. Severance length was affected by participant sex, fabric type, laundering and knife type. The severances formed in this study were not significantly affected by the amount a fabric was extended when stabbed. Variability was observed in the severance appearance among participants where prior training influenced the angle of impact and knife withdrawal technique.

  3. Detonation Wave Profile

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  4. Detonation command and control

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Detonation command and control

    Science.gov (United States)

    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.

  6. Mechanics of Stabbing: Biaxial Measurement of Knife Stab Penetration of Skin Simulant

    CERN Document Server

    Gilchrist, Michael D; Curtis, Michael; Cassidy, Mary; Byrne, Greg; Destrade, Michel; 10.1016/j.forsciint.2007.10.010

    2008-01-01

    In medicolegal situations, the consequences of a stabbing incident are described in terms that are qualitative without being quantitative. Here, the mechanical variables involved in knife-tissue penetration events are used to determine the parameters needed to be controlled in a measurement device. They include knife geometry, in-plane mechanical stress state of skin, angle and speed of knife penetration, and underlying fascia. Four household knives with different geometries were used. Synthetic materials were used to simulate the response of skin, fat and cartilage: polyurethane, foam, and ballistic soap, respectively. The force and energy applied by the blade and the skin displacement were used to identify skin penetration. The skin tension is shown to have a direct effect on the force and energy for knife penetration and on the depth of displacement of the simulant prior to penetration: larger levels of in-plane tension in the skin are associated with lower penetration forces, energies and displacements. L...

  7. A transnasal intracranial stab wound by a plastic-covered umbrella tip.

    Science.gov (United States)

    Ihama, Yoko; Nagai, Takumi; Ninomiya, Kenji; Fukasawa, Maki; Fuke, Chiaki; Miyazaki, Tetsuji

    2012-01-10

    A 48-year-old man died from a transnasal intracranial stab wound caused by an umbrella. The track of the stab passed from the right nostril, through the sphenoid sinus, the left side of the sella turcica and anterior clinoid process, and finally reached the surface of the brain. The stab wound crossed the left internal carotid artery, causing an exsanguination and aspiration of blood into the airway, resulting in death. It is extremely rare that an umbrella tip used during a struggle would stab the nostril of the victim. Transnasal intracranial stab wounds can be overlooked and require sensitive handling.

  8. An optimal dynamic interval stabbing-max data structure?

    DEFF Research Database (Denmark)

    Agarwal, Pankaj Kumar; Arge, Lars; Yi, Ke

    2005-01-01

    In this paper we consider the dynamic stabbing-max problem, that is, the problem of dynamically maintaining a set S of n axis-parallel hyper-rectangles in Rd, where each rectangle s ∈ S has a weight w(s) ∈ R, so that the rectangle with the maximum weight containing a query point can be determined...

  9. Class characteristics of serrated knife stabs to cartilage.

    Science.gov (United States)

    Pounder, Derrick J; Cormack, Lesley; Broadbent, Elizabeth; Millar, John

    2011-06-01

    A total of 136 stab wounds were made in cartilage with 8 serrated knives and 72 stabs with 4 nonserrated knives. The walls of the stab track were documented by photography, cast with dental impression material, and the casts photographed. Staining the translucent cartilage surface with blue or green food dye improved photography. Serrated blades produced striations on cartilage in all stabbings. Patterns of blade serration beyond the broad categories of coarse and fine were recognizable. The overall pattern of striations was "irregularly regular." The distance between the blade-spine wound end and the first serration striation is a class characteristic of the knife which produced the defect, as are distances to the subsequent serration striations, which become ever close together and eventually merge near the blade-edge wound end. Serrated knives may be ground (scalloped) on either the left side or the right side of the blade and this class characteristic is identifiable from the walls of the wound track, on which the scalloped blade surface produces broad ridges and narrow striation valleys, with a reverse image on the opposing wound wall. A drop point serrated blade consistently produced an additional oblique mark angled from the blade-spine wound end, accurately reflecting the shape of the blade tip, and representing a chatter mark.

  10. Ilu teadvustamine päästab maailma / Arthur Ruusmaa

    Index Scriptorium Estoniae

    Ruusmaa, Arthur

    1998-01-01

    Sõnum põlevkivimuuseumis toimunud Bulgaaria Roerichi Seltsi sekretäri Vencislav Simeoni, kes ise peab end rohkem portretistiks, Roerichi (1874-1947) vaimust kantud India reisil tehtud fotode näitusest "Ilu teadvustamine päästab maailma".

  11. Detonation safety of blasting caps

    Institute of Scientific and Technical Information of China (English)

    谢兴华; 彭小圣

    2002-01-01

    By means of researching into sympathetic detonation of blasting detonators in air, the regular patterns are concluded from blasting detonators interaction with the shock loading. The aerial distribution of initiating ability of detonators looks like a butterfly. The initiating ability mainly consists of shock wave, explosive gases and fliers. But fundamental questions remain. When does shock wave take the leading role? When and how does the explosive gases or the fliers take function? For those questions, there is less quantitative research. Through the theoretic deduction of the overpressure, the energy calculation of fliers and the experiment of sympathetic detonation of detonators, we can learn the sympathetic detonation distances of several kinds of detonators and make an inquiry into the lateral initiating regulations of detonators. So, we can provide the base data for the research into no sympathetic detonation of herd blasting detonators and then control the detonation between them. Then we can make full use of detonators and reduce the frequency of accidents caused by detonators.

  12. Striation patterns in serrated blade stabs to cartilage.

    Science.gov (United States)

    Pounder, Derrick J; Reeder, Francesca D

    2011-05-20

    Stab wounds were made in porcine cartilage with 13 serrated knives, amongst which 4 were drop-point and 9 straight-spine; 9 coarsely serrated, 3 finely serrated and 1 with mixed pattern serrations. The walls of the stab tracks were cast with dental impression material, and the casts photographed together with the knife blades for comparison. All 13 serrated blades produced an "irregularly regular" pattern of striations on cartilage in all stabbings. Unusual and distinctive blade serration patterns produced equally distinctive wound striation patterns. A reference collection of striation patterns and corresponding blades might prove useful for striation pattern analysis. Drop-point blades produced similar striations to straight-spine blades except that the striations were not parallel but rather fan-shaped, converging towards the wound exit. The fan-shaped striation pattern characteristic of drop-point blades is explained by the initial lateral movement of the blade through the cartilage imposed by the presence of the drop point shape. It appears that the greater the overall angle of the drop point, the shorter the blade length over which the drop point occurs, and the closer the first serration is to the knife tip, the more obvious is the fan-shaped pattern. We anticipate that micro-irregularities producing individualising characteristics in non-serrated drop point blades, provided they were located at the tip opposite the drop point, should also show a fan-shaped pattern indicative of a drop point blade. The examination of the walls of stab wounds to cartilage represents an under-utilised source of forensic information to assist in knife identification.

  13. The stab resistant properties of Kevlar/STF composites

    Science.gov (United States)

    Zhao, Jinhua; Cao, Hailin; Li, Xia; Wan, Junxi; Wang, Kun; Zhang, Jinfeng

    2012-04-01

    A colloidal shear thickening fluid (STF) was prepared by dispersing submicron silica particles in Polyethylene glycol 200(PEG200) with ball-milling technique. Kevlar/STF composites were fabricated by soaking Kevlar in the solution of STF diluted by ethanol. The rheological behavior of the fluid with various concentrations and the effect of dilution ratio on stab resistant properties of Kevlar/STF composites were studied. The result shows that the initial viscosity and the highest viscosity of the fluid increase as the weight fraction of SiO2 increasing with the weight fraction ranging from 50% to 60%, while the critical shear rate decrease as the weight fraction increasing. The fluid has notable shear thickening behavior at SiO2 weight fraction of 59%. Two solutions with 1:0.5 and 1:1weight ratio of STF:ethanol were used to fabricate Kevlar/STF composites. It is found that the composites fabricated by solution with dilution ratio 1:1 show better stab resistant properties. The Kevlar/STF composites exhibit better stab resistant properties than the neat Kevlar with the same areal density.

  14. The development of a stabbing machine for forensic textile damage analysis.

    Science.gov (United States)

    Benson, Natasha; Dos Santos, Robson Oliveria; Griffiths, Kate; Cole, Nerida; Doble, Philip; Roux, Claude; Blanes, Lucas

    2017-02-22

    This article describes the development of a horizontal stabbing machine with an interchangeable knife holder to simulate stab events. The machine consists of a motorised arm with a pneumatic system designed to deliver 60 unique stabbing positions. The mechanics were robust and the positioning system highly reproducible with standard deviations of less than 1.0mm in the x-axis and 2.3mm in the y-axis for a given stab position. The force of the instrument may be varied by the operator to a maximum of approximately 221N. The suitability of the instrument for simulating stab events was evaluated by measuring the severance length and textile damage from stab delivered from four different knives and nine penetrating angles.

  15. An Analytical Model for Predicting Stab Resistance of Flexible Woven Composites

    Science.gov (United States)

    Hou, Limin; Sun, Baozhong; Gu, Bohong

    2013-08-01

    Flexible woven composites have been widely used in geotextiles and light weight building structures. The stab resistance behavior of the flexible woven composite is an important factor for the application design. This paper reports an analytical model for predicting stab resistance of flexible woven composites under perpendicular stab with a blunt steel penetrator. The analytical model was established based on the microstructure and the deformation shape of the flexible woven composite under normal penetration. During the quasi-static stab penetration, the strain energies of warp and weft yarns and resins have been calculated. The stab resistance was calculated from the strain energies of the flexible woven composite. Furthermore, the contributions of the warp and weft yarns, resins to the stab resistance have been analyzed. It was found the three constituents have near the same contribution to the stab resistance. The higher value of weaving density, strength of yarns and especially the higher strength coating resins will lead the higher stab resistance. With the analytical model, the stab resistance would be expected to be designed in an efficient way with an acceptable precision.

  16. Detonation Jet Engine. Part 2--Construction Features

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. Detonation engines of various concepts, pulse detonation, rotational and engine with stationary detonation wave, are reviewed. Main trends in detonation engine development are discussed. The most important works that carried out…

  17. Variability of simulants used in recreating stab events.

    Science.gov (United States)

    Carr, D J; Wainwright, A

    2011-07-15

    Forensic investigators commonly use simulants/backing materials to mount fabrics and/or garments on when recreating damage due to stab events. Such work may be conducted in support of an investigation to connect a particular knife to a stabbing event by comparing the severance morphology obtained in the laboratory to that observed in the incident. There does not appear to have been a comparison of the effect of simulant type on the morphology of severances in fabrics and simulants, nor on the variability of simulants. This work investigates three simulants (pork, gelatine, expanded polystyrene), two knife blades (carving, bread), and how severances in the simulants and an apparel fabric typically used to manufacture T-shirts (single jersey) were affected by (i) simulant type and (ii) blade type. Severances were formed using a laboratory impact apparatus to ensure a consistent impact velocity and hence impact energy independently of the other variables. The impact velocity was chosen so that the force measured was similar to that measured in human performance trials. Force-time and energy-time curves were analysed and severance morphology (y, z directions) investigated. Simulant type and knife type significantly affected the critical forensic measurements of severance length (y direction) in the fabric and 'skin' (Tuftane). The use of EPS resulted in the lowest variability in data, further the severances recorded in both the fabric and Tuftane more accurately reflected the dimensions of the impacting knives.

  18. ABOUT THE DETONATION ENGINE

    Directory of Open Access Journals (Sweden)

    Bulat Pavel Viktorovich

    2014-01-01

    Full Text Available The research objects of this study are new principles of gas turbine and rocket engines working process organization, based on the oscillatory motion of shock and detonation waves. Purpose is to identify the state of level technology, describe the subject area, state the direction of research and formulate the main problems hindering the implementation of wave technology into mass production. The results presented in the study can be recommended for developers of aircraft engines, power and technological turbo-machinery.

  19. Detonation Properties of Bromonitromethane

    Science.gov (United States)

    Davis, Lloyd L.; Sheffield, Stephen A.; Engelke, Ray

    1999-06-01

    Bromonitromethane (CH_2BrNO_2)(BrNM) is chemically similar to nitromethane (NM), with one hydrogen atom replaced by bromine. It is a liquid explosive with an initial density of 2.009 g/cm^3. We have shown its sensitivity to shock to be similar to neat NM. However, its performance (CJ pressure) appears to be about twice that of NM. The sound speed of BrNM was measured to be 1.16 km/s and was used in the Universal Liquid Hugoniot (R. W. Woolfolk, M. Cowperthwaite and R. Shaw, Thermochimica Acta, 5), 409 (1983). to predict the unreacted Hugoniot. Shock Hugoniot measurements were shown to be consistent with this prediction. In addition, we report the BrNM detonation velocity, failure diameter in brass, and diameter effect curve. Detonation wave profiles obtained using VISAR to record the interface particle velocity between the detonating BrNM and a polymethyl methacrylate (PMMA) window have also been measured. There are interesting features in these measurements that may provide information about the reactions occurring in the BrNM and/or the effect of the confinement.

  20. Urogenital and Rectal Multisystem Organ Injury After Detonation of an Explosive Substance in the Rectum of a Schizophrenic Man

    Directory of Open Access Journals (Sweden)

    Ali E. Zumrutbas

    2014-05-01

    Full Text Available Penetrating injuries are caused by the injury of perineal area with gun or stab wounds, which may cause complex injuries or multiple organ injuries. Infections, bleeding, necrotizing fasciitis, ureterocutaneous fistulas, diverticulum, abscesses, narrowing, and incontinence may arise after urethral injuries. Although there are several case reports of urogenital system traumas in the literature, this case reports a schizophrenic patient who had a multisystem genitourinary and rectal trauma after self-detonation of an explosive in the rectum and managed with reconstructive surgery without any postoperative complications. Lower urinary tract anatomy was preserved and full continence was achieved after the surgical procedure.

  1. Tool mark striations in pig skin produced by stabs from a serrated blade.

    Science.gov (United States)

    Pounder, Derrick J; Bhatt, Shivani; Cormack, Lesley; Hunt, Bill A C

    2011-03-01

    Stab wounds produced by serrated blades are generally indistinguishable from stab wounds produced by non-serrated blades, except when visible tool mark striations are left on severed cartilage. Using a pig-skin experimental model, we explored the possibility that similar striations may be left in skin. Stabs into pig skin were made using a straight spine coarsely serrated blade (121), a drop point finely serrated blade (20), a clip point irregular coarsely serrated blade (20), a drop point coarsely serrated blade (15), and as controls 2 non-serrated blades (40). Tool mark striations could be seen on the skin wall of the stab canal in all stabs made using serrated blades but in none with non-serrated blades.The striation pattern, reflecting the class characteristics of the serrated blade, was the same as that described in cartilage but less well defined. Fixation of the specimen with Carnoy's solution best preserved visible striations, and fixation with formaldehyde after staining with 5% Neutral Red was also satisfactory. Casting with vinyl polysiloxane dental impression material greatly facilitated photo-documentation. Applying the technique to homicidal stabbings may help identify stab wounds produced with serrated blades.

  2. Benign positional vertigo

    Science.gov (United States)

    Vertigo - positional; Benign paroxysmal positional vertigo; BPPV: dizziness- positional ... Benign positional vertigo is also called benign paroxysmal positional vertigo (BPPV). It is caused by a problem in the inner ear. ...

  3. An Optimal Dynamic Data Structure for Stabbing-Semigroup Queries

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars; Kaplan, Haim;

    2012-01-01

    {R}$, the stabbing-semigroup query asks for computing $\\sum_{s \\in S(q)} \\omega(s)$. We propose a linear-size dynamic data structure, under the pointer-machine model, that answers queries in worst-case $O(\\log n)$ time and supports both insertions and deletions of intervals in amortized $O(\\log n)$ time....... It is the first data structure that attains the optimal $O(\\log n)$ bound for all three operations. Furthermore, our structure can easily be adapted to external memory, where we obtain a linear-size structure that answers queries and supports updates in $O(\\log_B n)$ I/Os, where B is the disk block size...

  4. Stab Wound to the Face. A Case Presentation

    Directory of Open Access Journals (Sweden)

    Yordany Boza Mejias

    2012-05-01

    Full Text Available The case of a young male patient aged 34, brown skinned, of rural origin and with a history of good health is presented. The patient was admitted at the Emergency Room of the Dr. Gustavo Aldereguía Lima General University Hospital in Cienfuegos. As a result of a fight, he had received a stab wound to the left lower side of the face. Therefore, surgical emergency treatment was applied. The objective of this presentation is to emphasize the importance of a multifactorial attention that allows covering all vital parameters and controlling the patient's hemodynamic status as well as that of the laboratory study, as appropriate, in order to obtain a rapid and effective behavior.

  5. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    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.

  6. The use of etoricoxib to treat an idiopathic stabbing headache: a case report

    Directory of Open Access Journals (Sweden)

    O'Connor Mortimer B

    2007-09-01

    Full Text Available Abstract According to the International Headache Society, idiopathic stabbing headache (ISH, an indomethacin-responsive headache syndrome, is a paroxysmal disorder of short duration manifested as head pain occurring as a single stab or a series of stabs involving the area supplied in the distribution of the first division of the trigeminal nerve. Stabs last for approximately a few seconds, occurring and recurring from once to multiple times per day in an irregular frequency, with no underlying attributable disorder. Previously indomethacin was the principle treatment option for ISH, despite therapeutic failure in up to 35% of cases, until reports showed gabapentin, melatonin and selective cyclo-oxygenase-2 (COX-2 inhibitors were also possibly effective. In this report we present the full case report of an 88 year old lady with a history of untreated ISH where etoricoxib, a selective COX-2 inhibitor, was used to effectively treat her ISH.

  7. Detonation in supersonic radial outflow

    KAUST Repository

    Kasimov, Aslan R.

    2014-11-07

    We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations are carried out in order to explore the stability of the steady-state solutions. It is found that both collapsing and expanding two-dimensional cellular detonations exist. The latter can be stabilized by putting several rigid obstacles in the flow downstream of the steady-state sonic locus. The problem of initiation of standing detonation stabilized in the radial flow is also investigated numerically. © 2014 Cambridge University Press.

  8. Investigations on multicycle spray detonations

    Institute of Scientific and Technical Information of China (English)

    LI Mu; YAN Chuanjun; ZHENG Longxi; WANG Zhiwu; QIU Hua

    2007-01-01

    Experimental investigations were carried out on a 50-I.D. Multicycle pulse detonation engine (PDE) model, and liquid fuel (gasoline) was used. The average of pressure peak, as measured by piezoelectricity pressure transducer, increased versus distance to thrust wall before fully-developed detonation came into being. According to the pressure history, the pressure in detonation tube would not rise abruptly until the flame front advanced a certain distance downstream the spark. Just at that moment, two compression waves spreading to opposite direction were formed. One was enforced by combustion and became detonation rapidly. The other was weakened because of obstacles and insufficiency of fuel. Two methods were used to determine the induction length of two-phase detonation wave through the pressure history. Ignition delay time was found to be longer than deflagration-to-detonation transition (DDT) time, and the sum of the two would change little as cycle frequency increased. So they could be the most important factors controlling two-phase PDE frequency. Filling process and blowdown process were also analyzed.

  9. Double-Front Detonation Waves

    Science.gov (United States)

    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. Diminishing detonator effectiveness through electromagnetic effects

    Energy Technology Data Exchange (ETDEWEB)

    Schill, Jr, Robert A.

    2016-09-20

    An inductively coupled transmission line with distributed electromotive force source and an alternative coupling model based on empirical data and theory were developed to initiate bridge wire melt for a detonator with an open and a short circuit detonator load. In the latter technique, the model was developed to exploit incomplete knowledge of the open circuited detonator using tendencies common to all of the open circuit loads examined. Military, commercial, and improvised detonators were examined and modeled. Nichrome, copper, platinum, and tungsten are the detonator specific bridge wire materials studied. The improvised detonators were made typically made with tungsten wire and copper (.about.40 AWG wire strands) wire.

  11. STAB INJURY: RETROSPECTIVE AND PROSPECTIVE STUDY IN TERTIARY CENTRE S IN CENTRAL INDIA

    Directory of Open Access Journals (Sweden)

    Raikwar

    2015-07-01

    Full Text Available AIMS AND OBJECTIVES: The aim of this study was to , 1. E valuate the incidence of stab injuries admitting in our institute, t o know various parameter and its association with injuries such as age group, sex ratio, clinical presentation . 2. V arious surgical interventi on and conservative treatment according the nature of stab injuries and through examination. 3. M orbidity and mortality of these patients , settings and design . The study was conducted in a retrospective and prospec tive manner and included cases b etween January 2009 and September 2013. METHODS AND MATERIAL S: 424 patients admitted with stab injuries in ICU and ward . Various surgical interventions were done according to standard indication such as laparotomies , thoracotomies, vascular repair etc. , and resul ts reported. RESULTS: Out of 424 patients t here were over all 413 mal es (97.4% and 11 female s (2.6% highest number of cases (226 in the third decade(21 - 30 i.e. 53.3% maximum number of cases are from 11 - 40 yrs. Majority of the stab wounds were homicidal in nature comprising 386 cases i.e. 91 % followed by are accidental. Chaku ( knife were the most common weapon . The Chaku was used in 351 cases i.e. 82.8% maximun numbers of patients 309 were presented with localised tende r ness at site of stab injury i.e 72.87%. In the perspective of management 244 abdominal stab that there were total 189(44.6% exploratory laparotomy . In 189 laparotomies peritoneal breech in 114 patients on local examination / exploration was the major indic ation there were 114 i.e ., 60.3% CONCLUSION: Stab injuri es are becoming common now a days because people often try to settle interpersonal relationship and political problems by mean of stabbing, although its incidence more in our country as compare d to European studies because of overpopulation unemployment and poverty. Incidence of stab injury can be reduced by improving the social morale of people especially the younger generation by

  12. Detonator assembly for oil well perforating gun

    Energy Technology Data Exchange (ETDEWEB)

    Regalbuto, J.A.

    1981-02-18

    A safe/arm detonator assembly for use with an oil well perforating gun assembly has 2 housing members isolated from well-bore fluid which are rotatable from a safe position wherein a detonator and a booster are held out of alignment, to an armed position wherein the detonator and booster are moved into alignment. The detonator assembly is further arranged to be installed in a well perforating gun assembly such that the gun assembly may be transported with the detonator assembly in the safe position, and rotated to the armed position at the well site without disassembling the gun assembly. A safety pin may protrude from one of the housing members across a cavity between the members to cover and protect the booster from accidental detonation when the detonator assembly is in the safe position. The detonator and booster cavities may be held aligned by a detent ball. 16 claims.

  13. [Penetrating stab injury to the lumbar spinal cord in a child].

    Science.gov (United States)

    Scheiderer, B; Mild, K; Gebhard, F; Scola, A

    2016-03-01

    This article reports the case of an 8-year-old boy with a knife stab injury to the lumbar spine without neurological deficits. The computed tomography (CT) scan revealed a longitudinal penetration of the conus medullaris at the level of the first lumbar vertebra. The knife blade was extracted and primary closure was carried out on the stab wound. The immediately postoperative magnetic resonance imaging (MRI) as well as the follow-up examinations after 1 and 6 weeks showed no evidence of compressive spinal bleeding, myelopathy or cerebrospinal fluid leakage. In addition, no secondary changes of the neurological status developed. Consequently, in cases of neurologically asymptomatic patients without concomitant injuries the surgical exploration of a stab wound does not seem to be absolutely necessary.

  14. Macroscopic and microscopic analysis of knife stab wounds on fleshed and clothed ribs.

    Science.gov (United States)

    Ferllini, Roxana

    2012-05-01

    Stab wounds upon bone are analyzed to interpret the weapon used and the physical context in which the attack occurred. The literature demonstrates that most research conducted pertaining to wound patterns has been carried out on defleshed and unclothed bone samples, not adequately replicating actual circumstances. For this research, six half pig torsos (Sus scrofa), fleshed (including muscle, fat, epidermis, and dermis layers) and clothed, were stabbed using three knife types, applying both straight and downward thrusts. Analysis conducted macroscopically and through a scanning electron microscope with an environmental secondary electron detector revealed a general lack of consistency in wound pattern and associated secondary effects. Consequently, it was not possible to establish wound pattern per knife type as suggested in previous research or relate it to stab motion. Advantage of microscopic analysis was evident in recognizing wound traits and observation of trace evidence not visible macroscopically.

  15. Detonation Jet Engine. Part 1--Thermodynamic Cycle

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

  16. Pulse detonation engines and components thereof

    Science.gov (United States)

    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.

  17. Turbulent deflagrations, autoignitions, and detonations

    KAUST Repository

    Bradley, Derek

    2012-09-01

    Measurements of turbulent burning velocities in fan-stirred explosion bombs show an initial linear increase with the fan speed and RMS turbulent velocity. The line then bends over to form a plateau of high values around the maximum attainable burning velocity. A further increase in fan speed leads to the eventual complete quenching of the flame due to increasing localised extinctions because of the flame stretch rate. The greater the Markstein number, the more readily does flame quenching occur. Flame propagation along a duct closed at one end, with and without baffles to increase the turbulence, is subjected to a one-dimensional analysis. The flame, initiated at the closed end of the long duct, accelerates by the turbulent feedback mechanism, creating a shock wave ahead of it, until the maximum turbulent burning velocity for the mixture is attained. With the confining walls, the mixture is compressed between the flame and the shock plane up to the point where it might autoignite. This can be followed by a deflagration to detonation transition. The maximum shock intensity occurs with the maximum attainable turbulent burning velocity, and this defines the limit for autoignition of the mixture. For more reactive mixtures, autoignition can occur at turbulent burning velocities that are less than the maximum attainable one. Autoignition can be followed by quasi-detonation or fully developed detonation. The stability of ensuing detonations is discussed, along with the conditions that may lead to their extinction. © 2012 by Pleiades Publishing, Ltd.

  18. Sensitized Liquid Hydrazine Detonation Studies

    Science.gov (United States)

    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.

  19. Virtual casting of stab wounds in cartilage using micro-computed tomography.

    Science.gov (United States)

    Pounder, Derrick J; Sim, Louise J

    2011-06-01

    In homicidal stabbings using a serrated knife, stab wounds involving costal cartilage leave striations on the cut surface of the cartilage from the serration points on the blade edge. Class characteristics of the serrated blade can be determined from the striation marks, and individualizing characteristics may be seen also. The traditional method for recording the striation marks involves the pernickety technique of casting with dental impression material. We assessed the potential utility of micro-computed tomography scanning of the stab track as a technique for nondestructive recording of striation patterns and virtual casting of them. Stab tracks in porcine cartilage, produced with a coarsely serrated blade, were scanned with a bench-top micro-computed tomography scanner. The typical irregularly regular striation pattern could be demonstrated, and the images manipulated, using proprietary software to produce a virtual cast. Whether the technology will have sufficient resolution to image not only class characteristic tool marks but also the much finer individualizing tool marks remains to be evaluated, but the technology shows considerable promise.

  20. Influence of Chemical Surface Modification of Woven Fabrics on Ballistic and Stab Protection of Multilayer Packets

    Directory of Open Access Journals (Sweden)

    Diana GRINEVIČIŪTĖ

    2014-06-01

    Full Text Available In order to achieve enhanced protective and wear (flexibility, less bulkiness properties of ballistic and stab protecting panels the investigation of chemical surface modification of woven p-aramid fabrics was performed applying different chemical composition shear thickening fluid (STF which improves friction inside fabric structure. For the chemical treatment silicic acid and acrylic dispersion water solutions were used and influence of their different concentrations on panels’ protective properties were investigated. Results of ballistic tests of multilayer protective panel have revealed that shear thickening effect was negligible when shooting at high energy range (E > 440 J. Determination of stab resistance of p-aramid panels has shown that different chemical composition of STFs had different influence on protective properties of the panels. Application of low concentrations of silicic acid determined higher stab resistance values comparing to higher concentrations of acrylic dispersion water solutions. At this stage of research stab tests results as ballistic ones determined that STF application for multilayer p-aramid fabrics protective panels is more efficient at low strike energy levels. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.3138

  1. Direct Initiation Through Detonation Branching in a Pulsed Detonation Engine

    Science.gov (United States)

    2008-03-01

    Detonation Engine The core of the PDE used in this research is a General Motors (GM) Quad 4 engine head with dual overhead camshafts . The head...manifold injection lines labeled The conventional poppet style valves are mechanically actuated by their respective camshafts which are in turn driven by...the angular position of the camshaft which is then used by the control computer to determine valve position and subsequent firing times. Depending

  2. Benign Paroxysmal Positional Vertigo (BPPV)

    Science.gov (United States)

    ... Rated Nonprofit! Volunteer. Donate. Review. Benign Paroxysmal Positional Vertigo (BPPV) BPPV is the most common vestibular disorder. Benign ... al. Diagnosis and management of benign paroxysmal positional vertigo (BPPV). CMAJ. 2003 169(7):681-693. Nuti D, ...

  3. Benign prostate hyperplasia (BPH) - resources

    Science.gov (United States)

    Resources - benign prostatic hyperplasia (BPH); Prostate enlargement resources; BPH resources ... The following organizations provide information on benign prostatic hyperplasia ( prostate enlargement ... Urology Care Foundation -- www. ...

  4. Influence of Lead Styphnate Content on the Functional Reliability of Some Detonator%斯蒂芬酸铅含量对某型雷管作用可靠性的影响❋

    Institute of Scientific and Technical Information of China (English)

    朱浩; 贠来峰; 李盘; 苏红强

    2016-01-01

    为解决某型雷管瞎火、半爆的问题,分析了工艺过程对针刺药组分和其中斯蒂芬酸铅含量的影响。试验结果表明,工艺过程中针刺药分药和回倒环节会引起针刺药中铅钡共晶含量的波动,当铅钡共晶中斯蒂芬酸铅的含量较低时会导致雷管作用失效。通过建立斯蒂芬酸铅含量与雷管作用可靠性的关系,合理解释了故障批产品几个异常现象,指出应通过使用较小的盒子盛装针刺药等措施来确保生产过程受控。%To solve dud and semi-explosion of some detonator, the influence of technological processes on compo-nents and lead styphnate content in stab powder were analyzed. Experimental results show that content of eutectic of lead and barium can be fluctuated by separating and re-spilling stab powder during production. The function failure of the deto-nator will be caused when the content of lead styphnate in eutectic of lead and barium is lower. According to the relation-ship between content of lead styphnate and functional reliability of the detonator, some unusual situations of the failure products are explained reasonably, and the control measure of using lesser boxes to fill stab powder is fingered out to insure production processes to be controlled.

  5. A summary of hydrogen-air detonation experiments

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Radioactive Fallout from Terrorist Nuclear Detonations

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Deflagrations and Detonations in Thermonuclear Supernovae

    CERN Document Server

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

    2004-01-01

    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 to 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.

  8. Laser diode initiated detonators for space applications

    Science.gov (United States)

    Ewick, David W.; Graham, J. A.; Hawley, J. D.

    1993-01-01

    Ensign Bickford Aerospace Company (EBAC) has over ten years of experience in the design and development of laser ordnance systems. Recent efforts have focused on the development of laser diode ordnance systems for space applications. Because the laser initiated detonators contain only insensitive secondary explosives, a high degree of system safety is achieved. Typical performance characteristics of a laser diode initiated detonator are described in this paper, including all-fire level, function time, and output. A finite difference model used at EBAC to predict detonator performance, is described and calculated results are compared to experimental data. Finally, the use of statistically designed experiments to evaluate performance of laser initiated detonators is discussed.

  9. Benign positional vertigo - aftercare

    Science.gov (United States)

    Vertigo - positional - aftercare; Benign paroxysmal positional vertigo - aftercare; BPPV - aftercare; Dizziness - positional vertigo ... Your health care provider may have treated your vertigo with the Epley maneuver . These are head movements ...

  10. REVERSIBLE CORTICAL BLINDNESS FOLLOWING SUCCESSFUL SURGICAL REPAIR OF TWO STAB WOUNDS IN THE HEART

    Directory of Open Access Journals (Sweden)

    Zaiton A

    2008-01-01

    Full Text Available This report describes a case of cortical blindness that followed successful surgical repair of two stab wounds in the heart in a 29-year old Libyan man. The patient presented in a state of pre cardiac arrest (shock and low cardiac output status, following multiple chest stab wounds. Chest tube was immediately inserted. Surgery was urgently performed suturing the two wounds; in the root of the aorta and in the left ventricle, and haemostasis was secured. Cardiac arrest was successfully prevented. The patient recovered smoothly, but 24 hours later he declared total blindness. Ophtalmic and neurological examinations and investigations that included fundoscopy, Electroencephalograms (EEGs and Computed Tomography Scans revealed no abnormalities, apart from absence of alpha waves in the EEGs. We diagnosed the case as cortical blindness and continued caring for the patient conservatively. Three days later, the patient regained his vision gradually and was discharged on the 7th postoperative day without any remarks.

  11. Suicide by skull stab wounds: a case of drug-induced psychosis.

    Science.gov (United States)

    Jousset, Nathalie; Rougé-Maillart, Clotilde; Turcant, Alain; Guilleux, Michel; Le Bouil, Anne; Tracqui, Antoine

    2010-12-01

    Suicide by stabbing to the head and/or driving sharp objects into the skull is of extreme rarity. This article reports the case of a 27-year-old man, who committed suicide by multiple knife stabs and cuts to the head, the torso, one shoulder and the forearms. Autopsy showed a perforating wound of the skull and the 10-cm long broken blade of the knife being still embedded in the right temporal lobe of the brain. The deceased had no history of psychiatric illness but was currently treated by mefloquine, a quinine derivative associated with a high rate of psychiatric adverse effects. Toxicological examination confirmed a recent intake of mefloquine together with chloroquine, another antimalarial drug. To our knowledge, this is the first report of a completed suicide with very strong evidence of mefloquine implication. Discussion focuses upon mefloquine-induced psychiatric disorders and highlights the importance of performing toxicological investigations in cases of unusual suicides.

  12. Reversible cortical blindness following successful surgical repair of two stab wounds in the heart.

    Science.gov (United States)

    El Gatit, A; Abdul Razeq, M; El Snaini, F; Saad, K; Zaiton, A

    2008-03-01

    This report describes a case of cortical blindness that followed successful surgical repair of two stab wounds in the heart in a 29-year old Libyan man. The patient presented in a state of pre cardiac arrest (shock and low cardiac output status), following multiple chest stab wounds. Chest tube was immediately inserted. Surgery was urgently performed suturing the two wounds; in the root of the aorta and in the left ventricle, and haemostasis was secured. Cardiac arrest was successfully prevented. The patient recovered smoothly, but 24 hours later he declared total blindness. Ophtalmic and neurological examinations and investigations that included fundoscopy, Electroencephalograms (EEGs) and Computed Tomography Scans revealed no abnormalities, apart from absence of alpha waves in the EEGs. We diagnosed the case as cortical blindness and continued caring for the patient conservatively. Three days later, the patient regained his vision gradually and was discharged on the 7(th) postoperative day without any remarks.

  13. Difficult Airway due to Retropharyngeal Hematoma after Stabbing to the Neck

    Directory of Open Access Journals (Sweden)

    Kouhei Iwashita

    2014-07-01

    Full Text Available Reports of retropharyngeal hematoma have been scarce in the anesthesiology literature. We report a patient whose trachea was difficult to intubate due to retropharyngeal hematoma after stabbing to the neck. A woman with a knife injury to the common carotid artery required emergency carotid arterioplasty. When tracheal intubation was attempted, marked swelling of the posterior pharyngeal wall made the vocal cords impossible to visualize. Preoperative computed tomography showed a retropharyngeal hematoma. The patient required mechanical ventilation for 2 days.

  14. Aortoduodenal fistula following aortic reconstruction of a pseudoaneurysm caused by stab wound 12 years ago

    OpenAIRE

    Zhou, Jian-Cang; Xu, Qiu-ping; Shen, Lai-gen; Pan, Kong-han; Mou, Yi-Ping

    2009-01-01

    Gastrointestinal bleeding due to aortoenteric fistula is extremely rare. Aortoenteric fistula is difficult to be diagnosed timely and entails a significant morbidity and mortality. Herein, we present an uncommon case of gastrointestinal bleeding caused by aortoduodenal fistula, which was a complication of a successful aortic reconstruction 4 months ago for an aortic pseudoaneurysm resulted from a stab wound 12 years ago. An urgent laparotomy confirmed an aortoduodenal fistula and repaired the...

  15. Exploratory study on new pulse detonation engines

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The worldwide progress in studies on pulse detonation engines (PDE) is briefly reviewed and some results of our exploratory study on PDE are presented. Analysis of thermodynamic cycle is made and the specific impulse formula is improved. A proof-of-principle experiment of a two-phase PDE is successfully carried out, using poor-detonable liquid C8H16/air mixture with a low-energy system (total spark energy of 50 mJ) and a newly developed one-step detonation initiation method. The measured detonation wave pressure ratio is very close to that of C-J detonation. The effects of length, diameter and detonation frequency on PDE performance are experimentally investigated. For liquid hydrocarbon fuel/air mixture, the PDE operation is successfully realized with an engine length of 1000 mm and detonation frequency up to 36 Hz, which has made an important step toward practical PDE. The developed code can be used for simulating PDE operation processes including deflagration to detonation transition (DDT) phenomenon. The numerical results are in good agreement with the experimental ones.

  16. VELOCITY OF DETONATION OF LOW DENSITY

    Directory of Open Access Journals (Sweden)

    Vinko Škrlec

    2012-12-01

    Full Text Available Blasting operations in built-up areas, at short distances from structures, impose new requirements on blasting techniques and properties of explosives in order to mitigate seismic effect of blasting. Explosives for civil uses are mixtures of different chemical composition of explosive and/or non-explosive substances. Chemical and physical properties, along with means of initiation, environment and the terms of application define detonation and blasting parameters of a particular type of the explosive for civil uses. Velocity of detonation is one of the most important measurable characteristics of detonation parameters which indirectly provide information about the liberated energy, quality of explosives and applicability for certain purposes. The level of shock effect of detonated charge on the rock, and therefore the level of seismic effect in the area, depends on the velocity of detonation. Since the velocity of detonation is proportional to the density of an explosive, the described research is carried out in order to determine the borderline density of the mixture of an emulsion explosive with expanded polystyrene while achieving stable detonation, and to determine the dependency between the velocity of detonation and the density of mixture (the paper is published in Croatian.

  17. Pulse Detonation Assessment for Alternative Fuels

    Directory of Open Access Journals (Sweden)

    Muhammad Hanafi Azami

    2017-03-01

    Full Text Available The higher thermodynamic efficiency inherent in a detonation combustion based engine has already led to considerable interest in the development of wave rotor, pulse detonation, and rotating detonation engine configurations as alternative technologies offering improved performance for the next generation of aerospace propulsion systems, but it is now important to consider their emissions also. To assess both performance and emissions, this paper focuses on the feasibility of using alternative fuels in detonation combustion. Thus, the standard aviation fuels Jet-A, Acetylene, Jatropha Bio-synthetic Paraffinic Kerosene, Camelina Bio-synthetic Paraffinic Kerosene, Algal Biofuel, and Microalgae Biofuel are all asessed under detonation combustion conditions. An analytical model accounting for the Rankine-Hugoniot Equation, Rayleigh Line Equation, and Zel’dovich–von Neumann–Doering model, and taking into account single step chemistry and thermophysical properties for a stoichiometric mixture, is applied to a simple detonation tube test case configuration. The computed pressure rise and detonation velocity are shown to be in good agreement with published literature. Additional computations examine the effects of initial pressure, temperature, and mass flux on the physical properties of the flow. The results indicate that alternative fuels require higher initial mass flux and temperature to detonate. The benefits of alternative fuels appear significant.

  18. 14 CFR 33.47 - Detonation test.

    Science.gov (United States)

    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...

  19. Pulse detonation assembly and hybrid engine

    Science.gov (United States)

    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.

  20. Developmental Venous Anomaly: Benign or Not Benign

    Science.gov (United States)

    AOKI, Rie; SRIVATANAKUL, Kittipong

    2016-01-01

    Developmental venous anomalies (DVAs), previously called venous angiomas, are the most frequently encountered cerebral vascular malformations. However, DVA is considered to be rather an extreme developmental anatomical variation of medullary veins than true malformation. DVAs are composed of dilated medullary veins converging centripetally into a large collecting venous system that drains into the superficial or deep venous system. Their etiology and mechanism are generally accepted that DVAs result from the focal arrest of the normal parenchymal vein development or occlusion of the medullary veins as a compensatory venous system. DVAs per se are benign and asymptomatic except for under certain unusual conditions. The pathomechanisms of symptomatic DVAs are divided into mechanical, flow-related causes, and idiopathic. However, in cases of DVAs associated with hemorrhage, cavernous malformations (CMs) are most often the cause rather than DVAs themselves. The coexistence of CM and DVA is common. There are some possibilities that DVA affects the formation and clinical course of CM because CM related to DVA is generally located within the drainage territory of DVA and is more aggressive than isolated CM in the literature. Brain parenchymal abnormalities surrounding DVA and cerebral varix have also been reported. These phenomena are considered to be the result of venous hypertension associated with DVAs. With the advance of diagnostic imagings, perfusion study supports this hypothesis demonstrating that some DVAs have venous congestion pattern. Although DVAs should be considered benign and clinically silent, they can have potential venous hypertension and can be vulnerable to hemodynamic changes. PMID:27250700

  1. Initiation of the Detonation in the Gravitationally Confined Detonation Model of Type Ia Supernovae

    Science.gov (United States)

    Seitenzahl, Ivo R.; Meakin, Casey A.; Lamb, Don Q.; Truran, James W.

    2009-07-01

    We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and

  2. Study of detonation wave contours in EFP warhead

    Directory of Open Access Journals (Sweden)

    Xu-dong Zu

    2016-04-01

    The results show that the planar detonation wave do better than the conical detonation and the spherical detonation wave in increasing the length–diameter ratio of explosively-formed projectiles (EFP and keep the nose of EFP integrated. The detonation wave can increase the length–diameter ratio of EFP when the wave shaper has the suitable thickness.

  3. Impact sensitivity and the maximum heat of detonation.

    Science.gov (United States)

    Politzer, Peter; Murray, Jane S

    2015-10-01

    We demonstrate that a large heat of detonation is undesirable from the standpoint of the impact sensitivity of an explosive and also unnecessary from the standpoints of its detonation velocity and detonation pressure. High values of the latter properties can be achieved even with a moderate heat of detonation, and this in turn enhances the likelihood of relatively low sensitivity.

  4. Benign Fibrous Histiocytoma

    Directory of Open Access Journals (Sweden)

    Pushpa Varma

    2014-01-01

    Full Text Available Fibrous histiocytomas (FHs are mesenchymal tumors that may be benign or malignant. Ocular involvement by FHs is infrequent and primarily limited to the orbit. Rarely, FHs can also involve the conjunctiva and perilimbal area. We report the case of a 38-year-old male with lid, conjunctival, and neck FHs. The diagnosis was confirmed by histopathology.

  5. Benign Prostatic Hyperplasia

    Science.gov (United States)

    ... prostate gets bigger, it may press on the urethra and cause the flow of urine to be slower and less forceful. "Benign" means the enlargement isn't caused by cancer or infection. "Hyperplasia" means enlargement. SymptomsWhat are the ...

  6. Transarterial coil embolization in treatment of gross hematuria following self-inflicted stab wound in a horse-shoe kidney

    Directory of Open Access Journals (Sweden)

    Pezeshki Rad Masoud

    2012-04-01

    Full Text Available 【Abstract】Horseshoe kidney is an uncommon anomaly of the urinary system with an increased risk of injury during penetrating and blunt abdominal traumas. Self-inflicted abdominal stab wound, a rare type of abdominal injury, accounts for only a small percentage of suicidal at-tempts and may be infrequently encountered by physicians in trauma centers. Psychiatric disorders and alcohol or drug abuse are common risk factors in cases of self-stabbing. Here we report a rare case of self-stabbing of a horseshoe kidney. The case was a 19-year-old man with self-inflicted abdominal stab wound who was referred to our department of radiology due to re-occurred gross hematuria three days after exploratory laparotomy and surgical repair of injured abdominal organs. A horseshoe kidney was incidentally found in the patient’s abdominal computed tomography. Renal angiography revealed active contrast extravasation from one of the segmental arteries. Selective transarterial embolization with a coil was successfully performed to con-trol the hematuria. Key words: Embolization, therapeutic; Kidney; Wounds, stab

  7. Comparative analysis of alternative fuels in detonation combustion

    OpenAIRE

    Azami, M. H.; Savill, Mark A.

    2016-01-01

    Detonation combustion prominently exhibits high thermodynamic efficiency which leads to better performance. As compared to the conventionally used isobaric heat addition in a Brayton cycle combustor, detonation uses a novel isochoric Humphrey cycle which utilises shocks and detonation waves to provide pressure-rise combustion. Such unsteady combustion has already been explored in wave rotor, pulse detonation engine and rotating detonation engine configurations as alternative technologies for ...

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

    Science.gov (United States)

    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].

  9. Critical Initiation Conditions for Gaseous Diverging Spherical Detonations

    OpenAIRE

    Desbordes, D.

    1995-01-01

    The diverging spherical detonation wave in gaseous explosives is obtained either with a point source of explosion of energy E or through the transmission of a plane detonation from a cylindrical tube of diameter d into a large volume. The mechanism of detonation initiation in both cases is based on the shock to detonation transition. The experimental critical conditions lead to an initiation criterion for detonation resulting from the competition between the expansion behind the leading shock...

  10. Cellular Cell Bifurcation of Cylindrical Detonations

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-Lai; JIANG Zong-Lin; WANG Chun; ZHANG Fan

    2008-01-01

    Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From the simulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearly self-sustained mechanism of detonations and finally lead to cell bifurcations.

  11. Stability of ZND detonations for Majda's model

    CERN Document Server

    Jung, Soyeun

    2012-01-01

    We evaluate by direct calculation the Lopatinski determinant for ZND detonations in Majda's model for reacting flow, and show that on the nonstable (nonnegative real part) complex half-plane it has a single zero at the origin of multiplicity one, implying stability. Together with results of Zumbrun on the inviscid limit, this recovers the result of RoqueJoffre-Vila that viscous detonations of Majda's model also are stable for sufficiently small viscosity, for any fixed detonation strength, heat release, and rate of reaction.

  12. VLW equation of state of detonation products

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the virial theory, we proposed VLW equation of state of detonation products (VLW EOS). Its basic theory and applications were described. The distinct features of the VLW EOS were:First, the detonation performance of the new high energy density materials could be predicted more reliably. Second, it had extensive application. The detonation parameters of both the condensed high energy density materials and the gaseous fuel air explosives could be calculated. Moreover, combustion performance of propellants could also be precisely calculated. The calculation results were satisfactory.

  13. Stab injury and device implantation within the brain results in inversely multiphasic neuroinflammatory and neurodegenerative responses

    Science.gov (United States)

    Potter, Kelsey A.; Buck, Amy C.; Self, Wade K.; Capadona, Jeffrey R.

    2012-08-01

    An estimated 25 million people in the US alone rely on implanted medical devices, ˜2.5 million implanted within the nervous system. Even though many devices perform adequately for years, the host response to medical devices often severely limits tissue integration and long-term performance. This host response is believed to be particularly limiting in the case of intracortical microelectrodes, where it has been shown that glial cell encapsulation and localized neuronal cell loss accompany intracortical microelectrode implantation. Since neuronal ensembles must be within ˜50 µm of the electrode to obtain neuronal spikes and local field potentials, developing a better understanding of the molecular and cellular environment at the device-tissue interface has been the subject of significant research. Unfortunately, immunohistochemical studies of scar maturation in correlation to device function have been inconclusive. Therefore, here we present a detailed quantitative study of the cellular events and the stability of the blood-brain barrier (BBB) following intracortical microelectrode implantation and cortical stab injury in a chronic survival model. We found two distinctly inverse multiphasic profiles for neuronal survival in device-implanted tissue compared to stab-injured animals. For chronically implanted animals, we observed a biphasic paradigm between blood-derived/trauma-induced and CNS-derived inflammatory markers driving neurodegeneration at the interface. In contrast, stab injured animals demonstrated a CNS-mediated neurodegenerative environment. Collectively these data provide valuable insight to the possibility of multiple roles of chronic neuroinflammatory events on BBB disruption and localized neurodegeneration, while also suggesting the importance to consider multiphasic neuroinflammatory kinetics in the design of therapeutic strategies for stabilizing neural interfaces.

  14. Aortoduodenal fistula following aortic reconstruction of a pseudoaneurysm caused by stab wound 12 years ago

    Institute of Scientific and Technical Information of China (English)

    Jian-cang ZHOU; Qiu-ping XU; Lai-gen SHEN; Kong-han PAN; Yi-ping MOU

    2009-01-01

    Gastrointestinal bleeding due to aortoenteric fistula is extremely rare. Aortoenteric fistula is difficult to be diagnosed timely and entails a significant morbidity and mortality. Herein, we present an uncommon case of gastrointestinal bleeding caused by aortoduodenal fistula, which was a complication of a successful aortic reconstruction 4 months ago for an aortic pseudoaneurysm resulted from a stab wound 12 years ago. An urgent laparotomy confirmed an aortoduodenal fistula and repaired the defects in aorta and duodenum, but a prolonged shock led to the patient's death. In summary, early diagnosis and surgical intervention for aortoenteric fistula are vital for survival.

  15. Early MRI findings in stab wound of the cervical spine: two case reports

    Energy Technology Data Exchange (ETDEWEB)

    Alkan, A.; Baysal, T.; Sarac, K.; Sigirci, A.; Kutlu, R. [Inonu Universitesi Turgut Ozal Tip Merkezi, Radyoloji Anabilim Dali, Malatya (Turkey)

    2002-01-01

    MR imaging was found to be the most sensitive modality for the detection of spinal cord abnormalities in the acutely injured spine. Although it is reported that traumatic pneumomyelogram indicates a base-of-skull or middle cranial fossa fracture and is almost certainly associated with intracranial subarachnoid air, early MR imaging may demonstrate subarachnoid air in penetrating trauma of the spinal cord without head injury. We report two cervical-spine stab-wound cases, one of which had subarachnoid air on early MR findings. (orig.)

  16. Delayed myelopathy secondary to stab wound with a retained blade tip within the laminae: case report.

    Science.gov (United States)

    Wang, Hui; Ma, Lei; Ding, Wen-Yuan

    2015-01-01

    Delayed neurologic deficit after a stab wound with a retained foreign body near the spinal canal is unusual, adequate radiological examination is fundamental in detecting retained foreign bodies, especially the CT scan, surgical extraction of the foreign body is the primary task and the surgical outcome is satisfactory. Here, we report a rare case of delayed myelopathy caused by spinal stenosis secondary to broken blade tip within thoracic laminae in an old man, who was injured in a knife attack 39 years ago. The incidence, clinical presentation, diagnosis and prognosis are discussed.

  17. Benign Prostatic Hyperplasia

    OpenAIRE

    Gil Ortega, Joan

    2015-01-01

    Benign prostatic hyperplasia (BPH) is a prevalent disease but its molecular mechanism remains unknown. Using human tissue samples from 16 patients diagnosed with BPH, we performed an ultrastructural study to clarify the mechanism and the role of glandular cells in this pathology. We have made a description of all the changes that suffers the prostatic epithelium. We have shown that the glandular architecture presents many non-physiological forms such as papillae and papillary fronds. Basal c...

  18. Deflagration to Detonation Transition in Thermonuclear Supernovae

    CERN Document Server

    Khokhlov, A M; Wheeler, J C

    1996-01-01

    We 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. We 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 simeq 5 x 10^6 g cm^-3, it is much smaller than the size of a white dwarf. We derive the critical turbulent intensity required to create the mixed region inside an active deflagration front in which a detonation can form. We conclude that the density rho_tr at which a detonation can form in a carb...

  19. Qualitative and Asymptotic Theory of Detonations

    KAUST Repository

    Faria, Luiz

    2014-11-09

    Shock waves in reactive media possess very rich dynamics: from formation of cells in multiple dimensions to oscillating shock fronts in one-dimension. Because of the extreme complexity of the equations of combustion theory, most of the current understanding of unstable detonation waves relies on extensive numerical simulations of the reactive compressible Euler/Navier-Stokes equations. Attempts at a simplified theory have been made in the past, most of which are very successful in describing steady detonation waves. In this work we focus on obtaining simplified theories capable of capturing not only the steady, but also the unsteady behavior of detonation waves. The first part of this thesis is focused on qualitative theories of detonation, where ad hoc models are proposed and analyzed. We show that equations as simple as a forced Burgers equation can capture most of the complex phenomena observed in detonations. In the second part of this thesis we focus on rational theories, and derive a weakly nonlinear model of multi-dimensional detonations. We also show, by analysis and numerical simulations, that the asymptotic equations provide good quantitative predictions.

  20. Effect of Resolution on Propagating Detonation Wave

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  1. Detonating Cord for Flux Compression Generation using Electrical Detonator No. 33

    Directory of Open Access Journals (Sweden)

    P B. Wagh

    2011-01-01

    Full Text Available The paper highlights the use of electrical detonators for magnetic flux compression generator applications which requires synchronisation of two events with precise time delay of tens of ms and jitter within a few ms. These requirements are generally achieved by exploding bridge wire type detonators which are difficult to develop and are not commercially available. A technique has been developed using commercially available electrical detonator no. 33 to synchronise between peak of seed current in stator coil and detonation of explosive charge in armature. In present experiments, electrical signal generated by self-shorting pin due to bursting of electrical detonator has been used to trigger the capacitor discharge and the detonating cord of known length has been used to incorporate predetermined delay to synchronise the events. It has been demonstrated that using electrical detonator and known length of detonating cord, the two events can be synchronised with predetermined delay between 31 and 251 ms with variation of ± 0.5ms. The technique developed is suitable for defence applications like generation of high power microwaves using explosive driven magnetic flux compression generators.Defence Science Journal, 2011, 61(1, pp.19-24, DOI:http://dx.doi.org/10.14429/dsj.61.30

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Gaseous detonation synthesis and characterization of nano-oxide

    Science.gov (United States)

    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.

  4. Detonation nanodiamonds for doping Kevlar.

    Science.gov (United States)

    Comet, Marc; Pichot, Vincent; Siegert, Benny; Britz, Fabienne; Spitzer, Denis

    2010-07-01

    This paper reports on the first attempt to enclose diamond nanoparticles--produced by detonation--into a Kevlar matrix. A nanocomposite material (40 wt% diamond) was prepared by precipitation from an acidic solution of Kevlar containing dispersed nanodiamonds. In this material, the diamond nanoparticles (Ø = 4 nm) are entirely wrapped in a Kevlar layer about 1 nm thick. In order to understand the interactions between the nanodiamond surface and the polymer, the oxygenated surface functional groups of nanodiamond were identified and titrated by Boehm's method which revealed the exclusive presence of carboxyl groups (0.85 sites per nm2). The hydrogen interactions between these groups and the amide groups of Kevlar destroy the "rod-like" structure and the classical three-dimensional organization of this polymer. The distortion of Kevlar macromolecules allows the wrapping of nanodiamonds and leads to submicrometric assemblies, giving a cauliflower structure reminding a fractal object. Due to this structure, the macroscopic hardness of Kevlar doped by nanodiamonds (1.03 GPa) is smaller than the one of pure Kevlar (2.31 GPa). To our knowledge, this result is the first illustration of the change of the mechanical properties induced by doping the Kevlar with nanoparticles.

  5. Review on Recent Advances in Pulse Detonation Engines

    Directory of Open Access Journals (Sweden)

    K. M. Pandey

    2016-01-01

    Full Text Available Pulse detonation engines (PDEs are new exciting propulsion technologies for future propulsion applications. The operating cycles of PDE consist of fuel-air mixture, combustion, blowdown, and purging. The combustion process in pulse detonation engine is the most important phenomenon as it produces reliable and repeatable detonation waves. The detonation wave initiation in detonation tube in practical system is a combination of multistage combustion phenomena. Detonation combustion causes rapid burning of fuel-air mixture, which is a thousand times faster than deflagration mode of combustion process. PDE utilizes repetitive detonation wave to produce propulsion thrust. In the present paper, detailed review of various experimental studies and computational analysis addressing the detonation mode of combustion in pulse detonation engines are discussed. The effect of different parameters on the improvement of propulsion performance of pulse detonation engine has been presented in detail in this research paper. It is observed that the design of detonation wave flow path in detonation tube, ejectors at exit section of detonation tube, and operating parameters such as Mach numbers are mainly responsible for improving the propulsion performance of PDE. In the present review work, further scope of research in this area has also been suggested.

  6. Radiotherapy of benign diseases

    Energy Technology Data Exchange (ETDEWEB)

    Haase, W.

    1982-10-11

    Still today radiotherapy is of decisive relevance for several benign diseases. The following ones are briefly described in this introductory article: 1. Certain inflammatory and degenerative diseases as furuncles in the face, acute thrombophlebitis, recurrent pseudoriparous abscesses, degenerative skeletal diseases, cervical syndrome and others; 2. rheumatic joint diseases; 3. Bechterew's disease; 4. primary presenile osteoporosis; 5. syringomyelia; 6. endocrine ophthalmopathy; 7. hypertrophic processes of the connective tissue; 8. hemangiomas. A detailed discussion and a profit-risk analysis is provided in the individual chapters of the magazine.

  7. Benign cephalic histiocytosis.

    Science.gov (United States)

    Gianotti, F; Caputo, R; Ermacora, E; Gianni, E

    1986-09-01

    Benign cephalic histiocytosis is a self-healing non-X, nonlipid cutaneous histiocytosis of children, characterized by a papular eruption on the head. Mucous membranes and viscera are always spared. In the 13 cases reported herein, the children were otherwise in good general health. The disease appeared during the first three years of life, and spontaneous regression was complete by the age of nine years in the four cases healed to date. The histiocytic infiltrate was localized in the upper and middle dermis and contained no lipids at any stage of evolution. All the histiocytes contained coated vesicles, and 5% to 30% also contained comma-shaped bodies in their cytoplasm.

  8. How sharp is sharp? Towards quantification of the sharpness and penetration ability of kitchen knives used in stabbings.

    Science.gov (United States)

    Hainsworth, S V; Delaney, R J; Rutty, G N

    2008-07-01

    Stabbing is the most common method for violent death in the UK. As part of their investigation, forensic pathologists are commonly asked to estimate or quantify the degree of force required to create a wound. The force required to penetrate the skin and body by a knife is a complex function of the sharpness of the knife, the area of the body and alignment with cleavage lines of the skin, the angle of attack and the relative movement of the person stabbing relative to the victim being stabbed. This makes it difficult for the forensic pathologist to give an objective answer to the question; hence, subjective estimations are often used. One area where some degree of quantification is more tractable is in assessing how sharp an implement (particularly a knife) is. This paper presents results of a systematic study of how the different aspects of knife geometry influence sharpness and presents a simple test for assessing knife sharpness using drop testing. The results show that the radius of the blunt edge at the tip is important for controlling the penetration ability of a kitchen knife. Using high-speed video, it also gives insight into the mechanism of knife penetration into the skin. The results of the study will aid pathologists in giving a more informed answer to the question of the degree of force used in stabbing.

  9. Transarterial coil embolization in treatment of gross hematuria following self-inflicted stab wound in a horseshoe kidney

    Institute of Scientific and Technical Information of China (English)

    Masoud Pezeshki Rad; Hassan Ahmadnia; Mahboobeh Abedi; Mohammad Sadegh Abedi

    2012-01-01

    Horseshoe kidney is an uncommon anomaly of the urinary system with an increased risk of injury during penetrating and blunt abdominal traumas.Selfinflicted abdominal stab wound,a rare type of abdominal injury,accounts for only a small percentage of suicidal attempts and may be infrequently encountered by physicians in trauma centers.Psychiatric disorders and alcohol or drug abuse are common risk factors in cases of self-stabbing.Here we report a rare case of self-stabbing of a horseshoe kidney.The case was a 19-year-old man with self-inflicted abdominal stab wound who was referred to our department of radiology due to re-occurred gross hematuria three days after exploratory laparotomy and surgical repair of injured abdominal organs.A horseshoe kidney was incidentally found in the patient's abdominal computed tomography.Renal angiography revealed active contrast extravasation from one of the segmental arteries.Selective transarterial embolization with a coil was successfully performed to control the hematuria.

  10. Double detonation drivers for a shock tube/tunnel

    Institute of Scientific and Technical Information of China (English)

    CHEN; Hong; FENG; Heng; YU; Hongru

    2004-01-01

    Recent progress on detonation drivers is reviewed. Performances of the forward detonation driver and backward detonation driver have been observed. To eliminate occurrence of a Taylor wave following the detonation wave in the primary driver and to improve the performance of the detonation driver, an additional backward detonation driver was proposed to attach to the end of the forward detonation driver.When the ratio of the initial pressures between the additional and the primary drivers becomes larger than or equal to a critical value, the Taylor wave will disappear, and thus a homogeneous driving gas with high pressure and high temperature can be generated.Furthermore, an over-driving detonation wave will be also obtained, which can increase the driving capability.

  11. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)

    2007-04-30

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  12. Research on the Low Detonation Velocity Explosives Containing Nitroesters

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Some explosive mixtures detonating at low velocity were experimentally investigated. Detonation velocity and critical diameter were measured for mixtures,being different in composition and density. An attempt of physical and chemical interpretation of results obtained is also included.

  13. Initiation of the detonation in the gravitationally confined detonation model of Type Ia supernovae

    CERN Document Server

    Seitenzahl, Ivo R; Lamb, Don Q; Truran, James W

    2009-01-01

    We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from a flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from 1D simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave pre-conditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can o...

  14. Type Ia Supernova Explosion: Gravitationally Confined Detonation

    CERN Document Server

    Plewa, T; Lamb, D

    2004-01-01

    We present a new mechanism for Type Ia supernova explosions in massive white dwarfs. The proposed scenario follows from relaxing the assumption of symmetry in the model and involves a detonation created in an unconfined environment. The explosion begins with an essentially central ignition of stellar material initiating a deflagration. This deflagration results in the formation of a buoyantly-driven bubble of hot material that reaches the stellar surface at supersonic speeds. The bubble breakout forms a strong pressure wave that laterally accelerates fuel-rich outer stellar layers. This material, confined by gravity to the white dwarf, races along the stellar surface and is focused at the location opposite to the point of the bubble breakout. These streams of nuclear fuel carry enough mass and energy to trigger a detonation just above the stellar surface. The flow conditions at that moment support a detonation that will incinerate the white dwarf and result in an energetic explosion. The stellar expansion fol...

  15. Detonation Properties of Ammonium Dinitramide (ADN)

    Science.gov (United States)

    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.

  16. Stream of Reaction Products behind the Detonation Wave Front

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Embedded copper foils in a high explosive charge allow to see the stream of the reaction products behind the detonation front. With three individual firings in front of FXR it can be shown that the reaction products behind the detonation front are immediately going in the direction of the detonation front. But then the rarefaction fans are influencing strongly the further displacements.

  17. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deenergized circuits near detonators. 56.6402... 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...

  18. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deenergized circuits near detonators. 57.6402... 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....

  19. Linear elastic response of tubes to internal detonation loading

    NARCIS (Netherlands)

    Beltman, W.M.; Shepherd, J.E.

    2002-01-01

    This paper deals with the structural response of a tube to an internal gaseous detonation. An internal detonation produces a pressure load that propagates down the tube. Because the speed of the gaseous detonation can be comparable to the flexural wave group speed, excitation of flexural waves in th

  20. Differences between postmortem computed tomography and conventional autopsy in a stabbing murder case

    Directory of Open Access Journals (Sweden)

    Talita Zerbini

    2014-12-01

    Full Text Available Objective: The aim of the present work is to analyze the differences and similarities between the elements of a conventional autopsy and images obtained from postmortem computed tomography in a case of a homicide stab wound. Method: Comparison between the findings of different methods: autopsy and postmortem computed tomography. Results: In some aspects, autopsy is still superior to imaging, especially in relation to external examination and the description of lesion vitality. However, the findings of gas embolism, pneumothorax and pulmonary emphysema and the relationship between the internal path of the instrument of aggression and the entry wound are better demonstrated by postmortem computed tomography. Conclusions: Although multislice computed tomography has greater accuracy than autopsy, we believe that the conventional autopsy method is fundamental for providing evidence in criminal investigations.

  1. Diagnosis and Treatment of Penetrating Cardiac Injury One Year after Thoracic Stab Wound

    Directory of Open Access Journals (Sweden)

    MH Soltani

    2005-10-01

    Full Text Available In any patient with a history of penetrating thoracic trauma, cardiac injury must be kept in mind. Here, we describe a 36 years-old female referred to this hospital with severe chest pain and hypotension. After primary evaluation and suggestion of AMI, streptokinase was started for the patient and because of deterioration of vital signs, cardiac surgery consultation was requested. After performing urgent echocardiography, massive pericardial tamponade was detected. Visualization of a knife blade on C.X.R and past medical history of thoracic stab injury led to a diagnosis of delayed cardiac tamponade and urgent sternotomy was performed. The blade that had penetrated the right ventricular chamber was extracted. Six days after operation, patient was discharged without any problem. This case study suggests the importance of high suspicion to cardiac injury in any patient with chest pain and a history of chest trauma.

  2. Detonations and deflagrations in cosmological phase transitions

    CERN Document Server

    Megevand, Ariel

    2009-01-01

    We study the steady state motion of bubble walls in cosmological phase transitions. Taking into account the boundary and continuity conditions for the fluid variables, we calculate numerically the wall velocity as a function of the nucleation temperature, the latent heat, and a friction parameter. We determine regions in the space of these parameters in which detonations and/or deflagrations are allowed. In order to apply the results to a physical case, we calculate these quantities in a specific model, which consists of an extension of the Standard Model with singlet scalar fields. We also obtain analytic approximations for deflagrations and detonations.

  3. Spinal Cord Injury Caused by Stab Wounds: Incidence, Natural History, and Relevance for Future Research.

    Science.gov (United States)

    McCaughey, Euan J; Purcell, Mariel; Barnett, Susan C; Allan, David B

    2016-08-01

    Spinal cord injury caused by stab wounds (SCISW) results from a partial or complete transection of the cord, and presents opportunities for interventional research. It is recognized that there is low incidence, but little is known about the natural history or the patient's suitability for long-term clinical outcome studies. This study aims to provide population-based evidence of the demographics of SCISW, and highlight the issues regarding the potential for future research. The database of the Queen Elizabeth National Spinal Injuries Unit (QENSIU), the sole center for treating SCI in Scotland, was reviewed between 1994 and 2013 to ascertain the incidence, demographics, functional recovery, and mortality rates for new SCISW. During this 20 year period, 35 patients with SCISW were admitted (97.1% male, mean age 30.0 years); 31.4% had a cervical injury, 60.0% had a thoracic injury, and 8.6% had a lumbar injury. All had a neurological examination, with 42.9% diagnosed as motor complete on admission and 77.1% discharged as motor incomplete. A total of 70.4% of patients with an American Spinal Injury Association Impairment Scale (AIS) level of A to C on admission had an improved AIS level on discharge. Nine (25.7%) patients have died since discharge, with mean life expectancy for these patients being 9.1 years after injury (20-65 years of age). Patients had higher levels of comorbidities, substance abuse, secondary events, and poor compliance compared with the general SCI population, which may have contributed to the high mortality rate observed post-discharge. The low incidence, heterogeneous nature, spontaneous recovery rate, and problematic follow-up makes those with penetrating stab injuries of the spinal cord a challenging patient group for SCI research.

  4. Benign paroxysmal positional vertigo

    Directory of Open Access Journals (Sweden)

    Guo Xiang-Dong

    2011-01-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV is a common clinical disorder characterized by brief recurrent spells of vertigo often brought about by certain head position changes as may occur with looking up, turning over in bed, or straightening up after bending over. It is important to understand BPPV not only because it may avert expensive and often unnecessary testing, but also because treatment is rapid, easy, and effective in >90% of cases. The diagnosis of BPPV can be made based on the history and examination. Patients usually report episodes of spinning evoked by certain movements, such as lying back or getting out of bed, turning in bed, looking up, or straightening after bending over. At present, the generally accepted recurrence rate of BPPV after successful treatment is 40%-50% at 5 years of average follow-up. There does appear to be a subset of individuals prone to multiple recurrences.

  5. Study of the Detonation Phase in the Gravitationally Confined Detonation Model of Type Ia Supernovae

    CERN Document Server

    Meakin, Casey A; Townsley, Dean; Jordan, George C; Truran, James; Lamb, Don

    2008-01-01

    We study the gravitationally confined detonation (GCD) model of Type Ia supernovae through the detonation phase and into homologous expansion. In the GCD model, a detonation is triggered by the surface flow due to single point, off-center flame ignition in carbon-oxygen white dwarfs. The simulations are unique in terms of the degree to which non-idealized physics is used to treat the reactive flow, including weak reaction rates and a time dependent treatment of material in nuclear statistical equilibrium (NSE). Careful attention is paid to accurately calculating the final composition of material which is burned to NSE and frozen out in the rapid expansion following the passage of a detonation wave over the high density core of the white dwarf; and an efficient method for nucleosynthesis post-processing is developed which obviates the need for costly network calculations along tracer particle thermodynamic trajectories. Observational diagnostics are presented for the explosion models, including abundance strat...

  6. The Principal Aspects of Application of Detonation in Propulsion Systems

    Directory of Open Access Journals (Sweden)

    A. A. Vasil'ev

    2013-01-01

    Full Text Available The basic problems of application of detonation process in propulsion systems with impulse and continuous burning of combustible mixture are discussed. The results on propagation of detonation waves in supersonic flow are analyzed relatively to air-breathing engine. The experimental results are presented showing the basic possibility of creation of an engine with exterior detonation burning. The base results on optimization of initiation in impulse detonation engine are explained at the expense of spatial and temporal redistribution of an energy, entered into a mixture. The method and technique for construction of highly effective accelerators for deflagration to detonation transition are discussed also.

  7. Detonation performance of high-dense BTF charges

    Science.gov (United States)

    Dolgoborodov, A.; Brazhnikov, M.; Makhov, M.; Gubin, S.; Maklashova, I.

    2014-05-01

    New experimental data on detonation wave parameters and explosive performance for benzotrifuroxan are presented. Optical pyrometry was applied in order to measure the temperature and pressure of BTF detonation products. Chapman-Jouguet temperature was obtained as 3990 - 4170 K (charge densities 1.82 - 1.84 g/cc). The heat of explosion and the acceleration ability were measured also. It is also considered the hypothesis of formation of nanodiamond particles in detonation products directly behind the detonation front and influence of these processes on the temperature-time history in detonation products.

  8. Pulsating reverse detonation models of Type Ia supernovae. I. Detonation ignition

    OpenAIRE

    Bravo Guil, Eduardo; García Senz, Domingo

    2009-01-01

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf. Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabilized white dwarf. One of the possibilities that have been invoked is that an inefficient deflagration leads to the pulsation of a Chandr...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C. [Brookhaven National Lab., Upton, NY (United States)] [and others

    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.

  10. Detonation propagation in a high loss configuration

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Scott I [Los Alamos National Laboratory; Shepherd, Joseph E [CALTECH

    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.

  11. Detonation characteristics of ammonium nitrate products

    NARCIS (Netherlands)

    Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der

    2006-01-01

    The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers Associ

  12. Influence of and additives on acetylene detonation

    Science.gov (United States)

    Drakon, A.; Emelianov, A.; Eremin, A.

    2014-03-01

    The influence of and admixtures (known as detonation suppressors for combustible mixtures) on the development of acetylene detonation was experimentally investigated in a shock tube. The time-resolved images of detonation wave development and propagation were registered using a high-speed streak camera. Shock wave velocity and pressure profiles were measured by five calibrated piezoelectric gauges and the formation of condensed particles was detected by laser light extinction. The induction time of detonation development was determined as the moment of a pressure rise at the end plate of the shock tube. It was shown that additive had no influence on the induction time. For , a significant promoting effect was observed. A simplified kinetic model was suggested and characteristic rates of diacetylene formation were estimated as the limiting stage of acetylene polymerisation. An analysis of the obtained data indicated that the promoting species is atomic chlorine formed by pyrolysis, which interacts with acetylene and produces radical, initiating a chain mechanism of acetylene decomposition. The results of kinetic modelling agree well with the experimental data.

  13. Formation of transverse waves in oblique detonations

    NARCIS (Netherlands)

    Verreault, J.; Higgins, A.J.; Stowe, R.A.

    2013-01-01

    The structure of oblique detonation waves stabilized on a hypersonic wedge in mixtures characterized by a large activation energy is investigated via steady method of characteristics (MoC) calculations and unsteady computational flowfield simulations. The steady MoC solutions show that, after the tr

  14. Der benigne paroxysmale Lagerungsschwindel

    Directory of Open Access Journals (Sweden)

    Wiest G

    2004-01-01

    Full Text Available Der benigne paroxysmale Lagerungsschwindel (BPPV ist eine häufige Störung des peripheren Vestibularorgans, welche bei allen Patienten mit lageabhängigem Schwindel suspiziert werden sollte. Obwohl kurzzeitige Drehschwindelattacken als pathognomonisches Symptom gelten, weisen viele Patienten auch unsystematisierten Schwankschwindel auf, was die Diagnosestellung oft erschwert. Auslöser des BPPV sind Klziumkarbonatkristalle (Otokonien, welche sich aus der Otolithenmatrix des Utriculus lösen und in einen der drei Bogengänge gelangen. Die Diagnosestellung erfolgt mit spezifischen Provokations- bzw. Lagerungstests, um den entsprechenden Lagerungsschwindel und Nystagmus zu induzieren. Die von Semont und Epley entwickelten Befreiungsmanöver zielen darauf ab, die in den Bogengängen lokalisierten Partikel in den Utriculus zu repositionieren, wo sie keinen Drehschwindel mehr auslösen. Zur Unterscheidung des BPPV von einem zentralen Lageschwindel bzw. Nystagmus können neben der Latenz auch der Verlauf und die Dauer des Lagerungsnystagmus beitragen, von entscheidender Bedeutung in der Differentialdiagnose ist allerdings die Schlagrichtung des induzierten Nystagmus.

  15. Nihilism: a benign denial.

    Science.gov (United States)

    Skandalakis, John E; Mirilas, Petros

    2003-06-01

    Nihilism is the belief that all possible knowledge on a given topic has been amassed and codified. Ranging from benign denial to deliberate attempts at excommunication, nihilism is often encountered in the history of medicine. Eustachius, Columbus, and Sylvius strongly criticized Vesalius and defended the authority of Galen. Riolan fervently rejected Harvey's monumental work on the circulation of blood. Gross stated that no honest and sensible surgeon would ever sanction thyroidectomy. Sandstrom's discovery of the parathyroids was met with silence. Transplantation of parathyroids by Mandl was not appreciated when announced. Aristotle's dictum that the heart cannot withstand serious injury led to Paget's statement that cardiac surgery had reached the limits set by nature, which no new techniques could overcome. The first Billroth I operation was welcomed as, "Hopefully, also the last." Pancreatic surgery was opposed because the organ was of no clinical interest and was impossible for surgeons to reach. Pancreatic transplantation was rejected for many years, despite good results. When Blundell used blood transfusion for postpartum hemorrhage, critics averred that his next exploit would be radical removal of the spleen. Bassini stated that it could be risky to publish more about radical treatment of inguinal hernias. Carcinomas of the lower sigmoid and upper rectum were deemed untreatable because of their inaccessibility. Colostomy during pediatric surgery was rejected many times. Although it is difficult for the human mind to move from a familiar point of view, this propensity should not infect science, thereby impeding advancement.

  16. Benign anatomical mistakes: incidentaloma.

    Science.gov (United States)

    Mirilas, Petros; Skandalakis, J E

    2002-11-01

    The concept of the "incidentaloma," a totally asymptomatic nonfunctional tumor that is clinically and biochemically silent and discovered "incidentally" in a totally asymptomatic patient, is a by-product of the evolving diagnostic techniques of the last three decades. Various authors have used the concept for "incidental" findings during diagnostic workup for symptoms unrelated to adrenal disease, or for "incidental" adrenal tumors unrelated to symptoms that could potentially be of adrenal origin. "Incidentaloma" has been used to encompass a wide and heterogeneous spectrum of pathologic entities including adrenocortical and medullary tumors, benign or malignant lesions, hormonally active or inactive lesions, metastases, infections, granulomas, infiltrations, cysts and pseudocysts, hemorrhages, and pseudoadrenal masses. The term "incidentaloma" does not indicate whether the mass is functional, or malignant, or adrenocortical in origin. "Incidentaloma" has also appeared in the literature in reference to other endocrine organs such as pituitary, thyroid, and parathyroids, as well as the liver or kidney. We question the scientific justification for this neologism and suggest that it should be abolished. Questionable lesions should be clearly and simply described as "incidentally found."

  17. Numerical study of nonequilibrium plasma assisted detonation initiation in detonation tube

    Science.gov (United States)

    Zhou, Siyin; Wang, Fang; Che, Xueke; Nie, Wansheng

    2016-12-01

    Nonequilibrium plasma has shown great merits in ignition and combustion nowadays, which should be especially useful for hypersonic propulsion. A coaxial electrodes configuration was established to investigate the effect of alternating current (AC) dielectric barrier discharge nonequilibrium plasma on the detonation initiation process in a hydrogen-oxygen mixture. A discharge simulation-combustion simulation loosely coupled method was used to simulate plasma assisted detonation initiation. First, the dielectric barrier discharge in the hydrogen-oxygen mixture driven by an AC voltage was simulated, which takes 17 kinds of particles (including positively charged particles, negatively charged particles, and neutral particles) and 47 reactions into account. The temporal and spatial characteristics of the discharge products were obtained. Then, the discharge products were incorporated into the combustion model of a detonation combustor as the initial conditions for the later detonation initiation simulation. Results showed that the number density distributions of plasma species are different in space and time, and develop highly nonuniformly from high voltage electrode to grounded electrode at certain times. All the active species reach their highest concentration at approximately 0.6T (T denotes a discharge cycle). Compared with the no plasma case, the differences of flowfield shape mainly appear in the early stage of the deflagration to detonation transition process. None of the sub-processes (including the very slow combustion, deflagration, over-driven detonation, detonation decay, and propagation of a self-sustained stable detonation wave) have been removed by the plasma. After the formation of a C-J detonation wave, the whole flowfield remains unchanged. With the help of plasma, the deflagration to detonation transition (DDT) time and distance are reduced by about 11.6% and 12.9%, respectively, which should be attributed to the active particles effect of

  18. 19th Biannual Symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR)

    CERN Document Server

    Heller, Gerd; Krämer, Ewald; Wagner, Claus; Breitsamter, Christian

    2016-01-01

    This book presents contributions to the 19th biannual symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. Special emphasis is given to collaborative research projects conducted by German scientists and engineers from universities, research-establishments and industries. By addressing a number of cutting-edge applications, together with the relevant physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field. Though the book’s primary emphasis is on the aerospace context, it also addresses further important applications, e.g. in ground transportation and energy. .

  19. Fatal delayed cardiac tamponade due to rupture of micropseudoaneurysm of left anterior descending coronary artery following stab to the chest.

    Science.gov (United States)

    Xing, Jingjun; Li, Shangxun; Zhang, Lin; Yang, Yi; Duan, Yijie; Li, Wenhe; Zhou, Yiwu

    2015-01-01

    Traumatic coronary pseudoaneurysm has been described to be mainly associated to iatrogenic lesion of the coronary arteries. However, chest-stab-wound-related coronary pseudoaneurysm caused by isolated partial incision of a coronary artery giving rise to fatal delayed cardiac tamponade is very rare. We describe an autopsy case in which this potentially fatal complication developed 8 days later after a thoracic stab wound. Unfortunately, the imaging examination failed to detect this defect during hospitalization. Postmortem examination revealed that the posterior wall of the left anterior descending coronary artery was intact but that the anterior wall was incised, forming a micropseudoaneurysm which had ruptured. This case highlights that isolated coronary artery injuries must be considered in any patient with a penetrating wound to the thorax, and coronary pseudoaneurysms should not be missed in these patients.

  20. Unusual intracranial stab wounds inflicted with metal tent stakes for a case involving a family murder suicide.

    Science.gov (United States)

    Oki, Takahito; Asamura, Hideki; Hayashi, Tokutaro; Ota, Masao

    2010-10-10

    This article presents a highly unusual homicide involving intracranial stab wounds. Of three members of a family killed by intracranial stab wounds apparently inflicted with metal tent stakes, two also showed signs of wounds inflicted during an apparent struggle with the assailant. A wooden mallet appears to be the implement use to drive the metal stakes into the cranial cavity. In all victims, toxicological analysis indicated the presence of brotizolam at concentrations ranging from 30 to 50ngml(-1). The one victim who showed no signs of wounds incurred during a defensive struggle was found to have blood alcohol levels of 2.87mgml(-1). The assailant, another family member with a history of major psychiatric disorders, apparently committed suicide by drowning following the attacks.

  1. Model of non-ideal detonation of condensed high explosives

    Science.gov (United States)

    Smirnov, E. B.; Kostitsin, O. V.; Koval, A. V.; Akhlyustin, I. A.

    2016-11-01

    The Zeldovich-Neumann-Doering theory of ideal detonation allows one to describe adequately the detonation of charges with near-critical diameter. For smaller diameters, detonation velocity can differ significantly from an ideal value expected based on equilibrium chemical thermodynamics. This difference is quite evident when using non-ideal explosives; in certain cases, this value can be up to one third of ideal detonation velocity. Numerical simulation of these systems is a very labor-consuming process because one needs to compute the states inside the chemical reaction zone, as well as to obtain data on the equation of state of high-explosive detonation products mixture and on the velocity of chemical reaction; however, these characteristics are poorly studied today. For practical purposes, one can use the detonation shock dynamics model based on interrelation between local velocity of the front and its local curvature. This interrelation depends on both the equation of state of explosion products, and the reaction velocity; but the explicit definition of these characteristics is not needed. In this paper, experimental results are analyzed. They demonstrate interrelation between the local curvature of detonation front and the detonation velocity. Equation of detonation front shape is found. This equation allows us to predict detonation velocity and shape of detonation wave front in arbitrary geometry by integrating ordinary differential equation for the front shape with a boundary condition at the charge edge. The results confirm that the model of detonation shock dynamics can be used to describe detonation processes in non-ideal explosives.

  2. Benign Breast Problems and Conditions

    Science.gov (United States)

    ... with a needle. Another example is a simple fibroadenoma . Simple fibroadenomas usually shrink or go away on their own. ... Cyst: A sac or pouch filled with fluid. Fibroadenoma: A type of solid, benign breast mass. Hormone: ...

  3. Laparoscopy for benign disease: robotics.

    Science.gov (United States)

    Talamini, Mark A

    2003-12-01

    Currently available robotic surgical systems appear to be particularly suited for use in benign diseases of the gastrointestinal system. Minimally invasive operations for foregut conditions, such as gastroesophageal reflux disease and achalasia, require excellent visibility and precise tissue dissection. Benign lower gastrointestinal diseases, including inflammatory bowel disease and diverticulitis, also can be approached using robotic assistance. Disadvantages include expense and the loss of tactile feedback. Early clinical results are promising.

  4. Thermal degradation of two liquid fuels and detonation tests for pulse detonation engine studies

    Science.gov (United States)

    Rocourt, X.; Gillard, P.; Sochet, I.; Piton, D.; Prigent, A.

    2007-02-01

    The use of liquid fuels such as kerosene is of interest for the pulse detonation engine (PDE). Within this context, the aim of this work, which is a preliminary study, was to show the feasibility to initiate a detonation in air with liquid-fuel pyrolysis products, using energies and dimensions of test facility similars to those of PDEs. Therefore, two liquids fuels have been compared, JP10, which is a synthesis fuel generally used in the field of missile applications, and decane, which is one of the major components of standard kerosenes (F-34, Jet A1, ...). The thermal degradation of these fuels was studied with two pyrolysis processes, a batch reactor and a flow reactor. The temperatures varied from 600°C to 1,000°C and residence times for the batch reactor and the flow reactor were, respectively, between 10 30 s and 0.1 2 s. Subsequently, the detonability of synthetic gaseous mixtures, which was a schematisation of the decomposition state after the pyrolysis process, has been studied. The detonability study, regarding nitrogen dilution and equivalence ratio, was investigated in a 50 mm-diameter, 2.5 m-long detonation tube. These dimensions are compatible with applications in the aircraft industry and, more particularly, in PDEs. Therefore, JP10 and decane were compared to choose the best candidate for liquid-fuel PDE studies.

  5. Pulsating reverse detonation models of Type Ia supernovae. I: Detonation ignition

    CERN Document Server

    Bravo, Eduardo

    2009-01-01

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf. Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabilized white dwarf. One of the possibilities that have been invoked is that an inefficient deflagration leads to the pulsation of a Chandrasekhar-mass white dwarf, followed by formation of an accretion shock around a carbon-oxygen rich core. The accretion shock confines the core and transforms kinetic energy from the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work we explore the robustness of the detonation ignition for different PRD models characterized by the amount of mass burned during the deflagration phase, M_defl. The ev...

  6. Influence of Turbulent Fluctuations on Detonation Propagation

    CERN Document Server

    Maxwell, Brian McN; Lau-Chapdelaine, Sebastien S M; Falle, Sam A E G; Sharpe, Gary J; Radulescu, Matei I

    2016-01-01

    The present study addresses the reaction zone structure and burning mechanism of unstable detonations. Experiments investigated mainly two-dimensional methane-oxygen cellular detonations in a thin channel geometry. The sufficiently high temporal resolution permitted to determine the PDF of the shock distribution, a power-law with an exponent of -3, and the burning rate of unreacted pockets from their edges - through surface turbulent flames with a speed approximately 3-7 times larger than the laminar one at the local conditions. Numerical simulations were performed using a novel Large Eddy Simulation method where the reactions due to both auto-ignition and turbulent transport and treated exactly at the sub-grid scale in a reaction-diffusion formulation. The model is an extension of Kerstein & Menon's Linear Eddy Model for Large Eddy Simulation to treat flows with shock waves and rapid gasdynamic transients. The two-dimensional simulations recovered well the amplification of the laminar flame speed owing t...

  7. [Stab wound to the left solitary kidney: report of a case].

    Science.gov (United States)

    Rabii, R; Joual, A; Bennani, S; Hafiani, M; el Mrini, M; Benjelloun, S

    2000-08-01

    A forty-four-years old man with a left solitary kidney presented a stab wound in the left lumbar region. Upon admission, the patient was hemodynamically stable, the abdominal ultrasonography showed a small perirenal hematoma and the intravenous pyelography was normal. Two days later, he had no hematuria and was discharged from the hospital, with a computed tomography scan control two weeks later. Unfortunately, seven days later, the patient was admitted to emergency for left lumbar pain, a 40 degrees C fever and pyuria. The creatinine level was 72 ng/mL, and the computed tomography scan showed a large urohematoma. The patient was operated and required partial upper polar nephrectomy for distorted upper pole with infected hematoma. A large hematoma was removed and a nephrostomy tube was introduced. The renal function returned to normal six days postoperatively and the nephrostomy tube was removed after nephrostogram at 12 days. Concerning this uncommon case, we emphasize the advantage of the computed tomography scan and the necessity of emergency management in a patient with solitary traumatic kidney.

  8. Heat of detonation, the cylinder test, and performance munitions

    Energy Technology Data Exchange (ETDEWEB)

    Akst, I.B.

    1989-01-01

    Heats of detonation of CHNO explosives correlate well with copper cylinder test expansion data. The detonation products/calorimetry data can be used to estimate performance in the cylinder test, in munitions, and for new molecules or mixtures of explosives before these are made. Confidence in the accuracy of the performance estimates is presently limited by large deviations of a few materials from the regression predictions; but these same deviations, as in the insensitive explosive DINGU and the low carbon systems, appear to be sources of information useful for detonation and explosives research. The performance correlations are functions more of the detonation products and thermochemical energy than they are of the familiar parameters of detonation pressure and velocity, and the predictions are closer to a regression line on average than are those provided by CJ calculations. The prediction computations are simple but the measurements (detonation calorimetry/products and cylinder experiments) are not. 17 refs., 5 tabs.

  9. Benign mixed tumor of the lacrimal sac

    Directory of Open Access Journals (Sweden)

    Jong-Suk Lee

    2015-01-01

    Full Text Available Neoplasms of the lacrimal drainage system are uncommon, but potentially life-threatening and are often difficult to diagnose. Among primary lacrimal sac tumors, benign mixed tumors are extremely rare. Histologically, benign mixed tumors have been classified as a type of benign epithelial tumor. Here we report a case of benign mixed tumor of the lacrimal sac.

  10. A gasdynamic gun driven by gaseous detonation

    Science.gov (United States)

    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.

  11. Detonation of Meta-stable Clusters

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. A Novel Oblique Detonation Structure and Its Stability

    Institute of Scientific and Technical Information of China (English)

    TENG Hong-Hui; ZHAO Wei; JIANG Zong-Lin

    2007-01-01

    Oblique detonation structures induced by the wedge in the supersonic combustible gas mixtures are simulated numerically. The results show that the stationary oblique detonation structures are influenced by the gas flow Mach number, and a novel critical oblique detonation structure, which is characterized by a more complicated wave system, appears in the low Mach number cases. By introducing the inflow disturbance, its nonstationary evolution process is illustrated and its stability is verified.

  13. Development of millisecond and internal delayed electric detonators in Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, D.

    1986-01-01

    The stages of developing millisecond and internal delayed detonators are discussed. The problems of their practical introduction in Hungary as well as the economic background of their production are outlined. The present situation, i.e. production possibilities, application of different detonator types as well as the expected progress in the field of detonator production and use in mines endangered by fire-damp are dealt with.

  14. Transient heat transfer properties in a pulse detonation combustor

    OpenAIRE

    Fontenot, Dion G.

    2011-01-01

    Approved for public release; distribution is unlimited. The heat transfer along the axis of a pulse detonation combustor has been characterized for various frequencies and fill fractions at 2.5 atmospheres of pressure for chamber refresh conditions. In a pulse detonation combustor, a supersonic detonation wave is the method for transforming chemical energy into mechanical energy and the wave propagates much faster than the subsonic flames in devices such as rockets and ramjets. The flow...

  15. Experimental Magnetohydrodynamic Energy Extraction from a Pulsed Detonation

    Science.gov (United States)

    2015-03-01

    specific heat capacity, that would result in a 24% loss in energy for ionization. Second, the water and aqueous NaCl were added prior to detonation . This...Experimental Magnetohydrodynamic Energy Extraction from a Pulsed Detonation THESIS Kaz I. Teope, Captain, USAF AFIT-ENY-MS-15-M-224 DEPARTMENT OF THE... DETONATION THESIS Presented to the Faculty Department of Aeronautics and Astronautics Graduate School of Engineering and Management Air Force

  16. Generation of High Pressure and Temperature by Converging Detonation Waves

    Directory of Open Access Journals (Sweden)

    V. P. Singh

    1987-07-01

    Full Text Available Generation of high pressure and temperature has various applications in defence. Several techniques, viz flying plate method, collapsing of linear, convergence of detonation waves in solid explosives, have been established in this connection. In the present paper, converging detonation waves in solid explosives, where variable heat of detonation is being added to the front, is studied, by using Whitham's characteristics rule. Results are compared with those reported elsewhere.

  17. Generation of High Pressure and Temperature by Converging Detonation Waves

    OpenAIRE

    Singh, V. P.; Shukla, S K

    1987-01-01

    Generation of high pressure and temperature has various applications in defence. Several techniques, viz flying plate method, collapsing of linear, convergence of detonation waves in solid explosives, have been established in this connection. In the present paper, converging detonation waves in solid explosives, where variable heat of detonation is being added to the front, is studied, by using Whitham's characteristics rule. Results are compared with those reported elsewhere.

  18. Generation of high pressure and temperature by converging detonation waves

    Science.gov (United States)

    Singh, V. P.; Shukla, S. K.

    1987-07-01

    Generation of high pressure and temperature has various applications in defense. Several techniques, viz flying plate method, collapsing of linear, convergence of detonation waves in solid explosives, have been established in this connection. In this paper, converging detonation waves in solid explosives, where variable heat of detonation is being added to the front, are studied by using Whitham's characteristics rule. Results are compared with those reported elsewhere.

  19. Radical pancreaticoduodenectomy for benign disease.

    LENUS (Irish Health Repository)

    Kavanagh, D O

    2008-01-01

    Whipple\\'s procedure is the treatment of choice for pancreatic and periampullary malignancies. Preoperative histological confirmation of malignancy is frequently unavailable and some patients will subsequently be found to have benign disease. Here, we review our experience with Whipple\\'s procedure for patients ultimately proven to have benign disease. The medical records of all patients who underwent Whipple\\'s procedure during a 15-year period (1987-2002) were reviewed; 112 patients underwent the procedure for suspected malignancy. In eight cases, the final histology was benign (7.1%). One additional patient was known to have benign disease at resection. The mean age was 50 years (range: 30-75). The major presenting features included jaundice (five), pain (two), gastric outlet obstruction (one), and recurrent gastrointestinal haemorrhage (one). Investigations included ultrasound (eight), computerised tomography (eight), endoscopic retrograde cholangiopancreatography (seven; of these, four patients had a stent inserted and three patients had sampling for cytology), and endoscopic ultrasound (two). The pathological diagnosis included benign biliary stricture (two), chronic pancreatitis (two), choledochal cyst (one), inflammatory pseudotumour (one), cystic duodenal wall dysplasia (one), duodenal angiodysplasia (one), and granular cell neoplasm (one). There was no operative mortality. Morbidity included intra-abdominal collection (one), anastomotic leak (one), liver abscess (one), and myocardial infarction (one). All patients remain alive and well at mean follow-up of 41 months. Despite recent advances in diagnostic imaging, 8% of the patients undergoing Whipple\\'s procedure had benign disease. A range of unusual pathological entities can mimic malignancy. Accurate preoperative histological diagnosis may have allowed a less radical operation to be performed. Endoscopic ultrasound-guided fine needle aspirate (EUS-FNA) may reduce the need for Whipple\\'s operation

  20. Experimental study of the detonation of technical grade ammonium nitrate

    Science.gov (United States)

    Presles, Henri-Noël; Vidal, Pierre; Khasainov, Boris

    2009-11-01

    The detonation of technical grade ammonium nitrate at the density ρ=0.666 g/cm confined in PVC and steel tubes was experimentally studied. The results show that the detonation is self-sustained and steady in steel tubes with diameter as small as 12 mm. Critical detonation diameter lies between 8 and 12 mm in 2 mm thick steel tubes and between 55 and 81 mm in PVC tubes. These values testify a strong detonation sensitivity of this product. To cite this article: H.-N. Presles et al., C. R. Mecanique 337 (2009).

  1. A library of prompt detonation reaction zone data

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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)].

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

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q. [Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States); Fisher, R. T. [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Townsley, D. M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Meakin, C. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Reid, L. B. [NTEC Environmental Technology, Subiaco WA 6008 (Australia)

    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.

  4. The Detonation Mechanism of the Pulsationally Assisted Gravitationally Confined Detonation Model of Type Ia Supernovae

    Science.gov (United States)

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

    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 56Ni 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.

  5. Estimating heats of detonation and detonation velocities of aromatic energetic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Keshavarz, Mohammad Hossein [Department of Chemistry, Malek-ashtar University of Technology, Shahin-shahr, P. O. Box 83145/115 (Iran)

    2008-12-15

    A new method is introduced to predict reliable estimation of heats of detonation of aromatic energetic compounds. At first step, this procedure assumes that the heat of detonation of an explosive compound of composition C{sub a}H{sub b}N{sub c}O{sub d} can be approximated as the difference between the heat of formation of all H{sub 2}O-CO{sub 2} arbitrary (H{sub 2}O, CO{sub 2}, N{sub 2}) detonation products and that of the explosive, divided by the formula weight of the explosive. Overestimated results based on (H{sub 2}O-CO{sub 2} arbitrary) can be corrected in the next step. Predicted heats of detonation of pure energetic compounds with the product H{sub 2}O in the liquid state for 31 aromatic energetic compounds have a root mean square (rms) deviation of 2.08 and 0.34 kJ g{sup -1} from experiment for (H{sub 2}O-CO{sub 2} arbitrary) and new method, respectively. The new method also gives good results as compared to the second sets of decomposition products, which consider H{sub 2},N{sub 2}, H{sub 2}O,CO, and CO{sub 2} as major gaseous products. It is shown here how the predicted heats of detonation by the new method can be used to obtain reliable estimation of detonation velocity over a wide range of loading densities. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  6. Cholesterol and benign prostate disease.

    Science.gov (United States)

    Freeman, Michael R; Solomon, Keith R

    2011-01-01

    The origins of benign prostatic diseases, such as benign prostatic hyperplasia (BPH) and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), are poorly understood. Patients suffering from benign prostatic symptoms report a substantially reduced quality of life, and the relationship between benign prostate conditions and prostate cancer is uncertain. Epidemiologic data for BPH and CP/CPPS are limited, however an apparent association between BPH symptoms and cardiovascular disease (CVD) has been consistently reported. The prostate synthesizes and stores large amounts of cholesterol and prostate tissues may be particularly sensitive to perturbations in cholesterol metabolism. Hypercholesterolemia, a major risk factor for CVD, is also a risk factor for BPH. Animal model and clinical trial findings suggest that agents that inhibit cholesterol absorption from the intestine, such as the class of compounds known as polyene macrolides, can reduce prostate gland size and improve lower urinary tract symptoms (LUTS). Observational studies indicate that cholesterol-lowering drugs reduce the risk of aggressive prostate cancer, while prostate cancer cell growth and survival pathways depend in part on cholesterol-sensitive biochemical mechanisms. Here we review the evidence that cholesterol metabolism plays a role in the incidence of benign prostate disease and we highlight possible therapeutic approaches based on this concept.

  7. Study on stab-resistant performance of STF/UHMWPE fabric composite materials%STF/UHMWPE织物复合材料防刺性能的研究

    Institute of Scientific and Technical Information of China (English)

    徐素鹏; 张玉芳

    2012-01-01

    为拓宽STF/防刺织物复合材料的种类,寻求更轻、更薄、更软和更经济的防刺材料,用原生粒径20nm的SiO2分散于PEG200中制得不同SiO2含量的STF,通过浸泡的方式制备出STF/UHMWPE织物复合材料.参照GA68-2003《防刺服》标准,在TLC-30A微处理器控制落锤式防刺服专用冲击试验机上测定不同条件下STF/UHMWPE复合材料的防刺性能.结果表明,STF能明显增强UHMWPE织物的防刺性能,STF/UHMWPE无纺布复合材料的防刺性能优于STF/UHMWPE机织布复合材料;并且随着STF固含量的增大,STF增强织物防刺性能的效果越显著; STF/UHMWPE复合材料与纯UHMWPE复合铺层的防刺性能优于STF/UHMWPE复合材料单独铺层时,而且STF/UHMWPE复合材料放在最上层效果较好.%To broaden STF/UHMWPE stab-resistant composite materials species and seek more milder, thinner,better and economical stab-resistant materials, STF with different amount of nano-SiO2 was prepared by dispering nano-SiO2 with particle size 20 nm in PEG200,then STF/UHMWPE stab-resistant composite materials were prepared by immersion ways. The stab-resistant behavior of composite materials in different conditions was tested by falling tup machine controlled by TLC-30A microprocessor and referring to GA 68—2003 "stab-resistant body armor". The results indicate that stab-resistant performance of UHMWPE fabric is enhanced obviously by STF, the stab-resistant performance of STF/UHMWPE non-woven fabric composite materials is better than STF/UHMWPE woven fabric composite materials; and with increasing solids content of STF, the effects of STF enhancing UHMWPE fabric's stab-resistant performance are more significant; the stab-resistant performance of STF/UHMWPE composite materials and pure UHMWPE plying compundly is better than plying individually, and composite materials plied upper are better.

  8. Discrete approximations of detonation flows with structured detonation reaction zones by discontinuous front models: A program burn algorithm based on detonation shock dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bdzil, J.B. [Los Alamos National Lab., NM (United States); Jackson, T.L. [Univ. of Illinois, Urbana, IL (United States). Center for Simulation of Advanced Rockets; Stewart, D.S. [Univ. of Illinois, Urbana, IL (United States). Theoretical and Applied Mechanics

    1999-02-02

    In the design of explosive systems the generic problem that one must consider is the propagation of a well-developed detonation wave sweeping through an explosive charge with a complex shape. At a given instant of time the lead detonation shock is a surface that occupies a region of the explosive and has a dimension that is characteristic of the explosive device, typically on the scale of meters. The detonation shock is powered by a detonation reaction zone, sitting immediately behind the shock, which is on the scale of 1 millimeter or less. Thus, the ratio of the reaction zone thickness to the device dimension is of the order of 1/1,000 or less. This scale disparity can lead to great difficulties in computing three-dimensional detonation dynamics. An attack on the dilemma for the computation of detonation systems has lead to the invention of sub-scale models for a propagating detonation front that they refer to herein as program burn models. The program burn model seeks not to resolve the fine scale of the reaction zone in the sense of a DNS simulation. The goal of a program burn simulation is to resolve the hydrodynamics in the inert product gases on a grid much coarser than that required to resolve a physical reaction zone. The authors first show that traditional program burn algorithms for detonation hydrocodes used for explosive design are inconsistent and yield incorrect shock dynamic behavior. To overcome these inconsistencies, they are developing a new class of program burn models based on detonation shock dynamic (DSD) theory. It is hoped that this new class will yield a consistent and robust algorithm which reflects the correct shock dynamic behavior.

  9. Design of environmentally benign processes

    DEFF Research Database (Denmark)

    Hostrup, Martin; Harper, Peter Mathias; Gani, Rafiqul

    1999-01-01

    This paper presents a hybrid method for design of environmentally benign processes. The hybrid method integrates mathematical modelling with heuristic approaches to solving the optimisation problems related to separation process synthesis and solvent design and selection. A structured method...... of solution, which employs thermodynamic insights to reduce the complexity and size of the mathematical problem by eliminating redundant alternatives, has been developed for the hybrid method. Separation process synthesis and design problems related to the removal of a chemical species from process streams...... mixture and the second example involves the determination of environmentally benign substitute solvents for removal of a chemical species from wastewater. (C) 1999 Elsevier Science Ltd. All rights reserved....

  10. Multicystic Benign Mesothelioma Complicating Pregnancy.

    Science.gov (United States)

    Tamhankar, V A

    2015-01-01

    Multicystic benign mesothelioma (MBM) is a rare peritoneal pathology typically affecting women in reproductive age. Though MBM is considered benign, these lesions are prone to recurrence and their growth could be modulated by the presence of oestrogen receptors. Acute presentation of MBM is still very rare in pregnancy and management options are not established. We describe a case of MBM presenting in early pregnancy with acute pain. This was successfully treated with surgical resection. Pregnancy continued uneventfully to term and no evidence of recurrent MBM was found at Caesarean section.

  11. Multicystic Benign Mesothelioma Complicating Pregnancy

    Directory of Open Access Journals (Sweden)

    V. A. Tamhankar

    2015-01-01

    Full Text Available Multicystic benign mesothelioma (MBM is a rare peritoneal pathology typically affecting women in reproductive age. Though MBM is considered benign, these lesions are prone to recurrence and their growth could be modulated by the presence of oestrogen receptors. Acute presentation of MBM is still very rare in pregnancy and management options are not established. We describe a case of MBM presenting in early pregnancy with acute pain. This was successfully treated with surgical resection. Pregnancy continued uneventfully to term and no evidence of recurrent MBM was found at Caesarean section.

  12. Stab Incision Glaucoma Surgery: A Modified Guarded Filtration Procedure for Primary Open Angle Glaucoma.

    Science.gov (United States)

    Jacob, Soosan; Figus, Michele; Ashok Kumar, Dhivya; Agarwal, Ashvin; Agarwal, Amar; Areeckal Incy, Saijimol

    2016-01-01

    Purpose. To describe a modified guarded filtration surgery, stab incision glaucoma surgery (SIGS), for primary open angle glaucoma (POAG). Methods. This prospective, interventional case series included patients with POAG (IOP ≥21 mmHg with glaucomatous visual field defects). After sliding superior conjunctiva down over limbus, 2.8 mm bevel-up keratome was used to create conjunctival entry and superficial corneoscleral tunnel in a single step starting 1.5 mm behind limbus. Lamellar corneoscleral tunnel was carefully dissected 0.5-1 mm into cornea and anterior chamber (AC) was entered. Kelly Descemet's punch (1 mm) was slid along the tunnel into AC to punch internal lip of the tunnel, thereby compromising it. Patency of ostium was assessed by injecting fluid in AC and visualizing leakage from tunnel. Conjunctival incision alone was sutured. Results. Mean preoperative IOP was 27.41 ± 5.54 mmHg and mean postoperative IOP was 16.47 ± 4.81 mmHg (n = 17). Mean reduction in IOP was 38.81 ± 16.55%. There was significant reduction of IOP (p < 0.000). 64.7% had IOP at final follow-up of <18 mmHg without medication and 82.35% had IOP <18 mmHg with ≤2 medications. No sight threatening complications were encountered. Conclusion. Satisfactory IOP control was noted after SIGS in interim follow-up (14.18 ± 1.88 months).

  13. Stab Incision Glaucoma Surgery: A Modified Guarded Filtration Procedure for Primary Open Angle Glaucoma

    Directory of Open Access Journals (Sweden)

    Soosan Jacob

    2016-01-01

    Full Text Available Purpose. To describe a modified guarded filtration surgery, stab incision glaucoma surgery (SIGS, for primary open angle glaucoma (POAG. Methods. This prospective, interventional case series included patients with POAG (IOP ≥21 mmHg with glaucomatous visual field defects. After sliding superior conjunctiva down over limbus, 2.8 mm bevel-up keratome was used to create conjunctival entry and superficial corneoscleral tunnel in a single step starting 1.5 mm behind limbus. Lamellar corneoscleral tunnel was carefully dissected 0.5–1 mm into cornea and anterior chamber (AC was entered. Kelly Descemet’s punch (1 mm was slid along the tunnel into AC to punch internal lip of the tunnel, thereby compromising it. Patency of ostium was assessed by injecting fluid in AC and visualizing leakage from tunnel. Conjunctival incision alone was sutured. Results. Mean preoperative IOP was 27.41±5.54 mmHg and mean postoperative IOP was 16.47±4.81 mmHg (n=17. Mean reduction in IOP was 38.81±16.55%. There was significant reduction of IOP (p<0.000. 64.7% had IOP at final follow-up of <18 mmHg without medication and 82.35% had IOP <18 mmHg with ≤2 medications. No sight threatening complications were encountered. Conclusion. Satisfactory IOP control was noted after SIGS in interim follow-up (14.18±1.88 months.

  14. Investigation on Novel Methods to Increase Specific Thrust in Pulse Detonation Engines via Imploding Detonations

    Science.gov (United States)

    2009-12-01

    to-Detonation Transition, Specific Thrust 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS...hydrocarbon fuel-air mixtures such as acetylene -air, ethylene-air, propane-air and even JP10-air mixtures based on the required length of the induction zone

  15. Predicting polarization signatures for double-detonation and delayed-detonation models of Type Ia supernovae

    CERN Document Server

    Bulla, M; Kromer, M; Seitenzahl, I R; Fink, M; Ciaraldi-Schoolmann, F; Roepke, F K; Hillebrandt, W; Pakmor, R; Ruiter, A J; Taubenberger, S

    2016-01-01

    Calculations of synthetic spectropolarimetry are one means to test multi-dimensional explosion models for Type Ia supernovae. In a recent paper, we demonstrated that the violent merger of a 1.1 and 0.9 M$_{\\odot}$ white dwarf binary system is too asymmetric to explain the low polarization levels commonly observed in normal Type Ia supernovae. Here, we present polarization simulations for two alternative scenarios: the sub-Chandrasekhar mass double-detonation and the Chandrasekhar mass delayed-detonation model. Specifically, we study a two-dimensional double-detonation model and a three-dimensional delayed-detonation model, and calculate polarization spectra for multiple observer orientations in both cases. We find modest polarization levels ($<$ 1 per cent) for both explosion models. Polarization in the continuum peaks at $\\sim$ 0.1$-$0.3 per cent and decreases after maximum light, in excellent agreement with spectropolarimetric data of normal Type Ia supernovae. Higher degrees of polarization are found ac...

  16. Is "Benign Childhood Epilepsy with Centrotemporal Spikes” Always Benign?

    Directory of Open Access Journals (Sweden)

    Muhammad SAEED

    2014-07-01

    Full Text Available How to Cite This Article: Saeed M, Azam M, Shabbir N, Qamar ShA. Is "Benign Childhood Epilepsy with Centrotemporal Spikes" Always Benign? Iran J Child Neurol. 2014 Summer;8(3: 39-45.AbstractObjectiveTo determine the prevalence of associated behavioral problems and prognosis with Benign Childhood Epilepsy with CentroTemporal Spikes (BCECTS.Descriptive, Cross Sectional study that was conducted from October 2009 to April 2013 in the Department of Pediatric Neurology, the Children’s Hospital Taif, KSA.Material & MethodsThis study was conducted after approval from the Ethics Committee of the Children’s Hospital Taif, Saudi Arabia. Thirty-two patients from the age of 3 to 10 years old were recruited from the pediatric neurology clinic over a period of 4 years. All the patients were selected based on history, EEGs, and neuropsychological and neurological examinations.EEGs were performed for all the patients while in awake and sleep states. Those who had centrotemporal discharges were included in the study. All the patients also underwent a brain MRI. Only two patients had mild cortical atrophy but developmentally they were normal.ResultsIn our study, prevalence of BRE is 32/430 (7.44%. Among the 32 cases, 24 were male and eight were female. Six cases out of 32 indicated a family history of BRE. Twenty-eight cases had unilateral right sided centrotemporal discharges and four had bilateral discharges.ConclusionIt is possible that for BECTS, a high number of seizures might play an important role in the development of mild cognitive impairment and/or behavior disturbances.ReferencesBradley WG, Daroff RB, Fenichel JM, Jahrovic J. Neurology of clinical practice. 5th Ed. 2009: pp. 1953-1990.Berg AT, Berkovic SF, Brodie MJ, Buchhalter J, Cross H, Van Emde Boas M, et al: Revised terminology and concepts for organization of seizures and epilepsies: Report of the ILAE Commission on Classification and Terminology, 2005–2009. Epilepsia. 2010

  17. Brief detonating characterization of lithanol; Caracterisation detonique succinte du lithanol

    Energy Technology Data Exchange (ETDEWEB)

    Morvan, J.; Courchinoux, R.; Darnez, Ch. [CEA Cesta, Centre d`Etudes Scientifiques et Techniques d`Aquitaine, 33 - Le Barp (France)

    1996-12-31

    Lithanol is a stoichiometric composition of tri-hydrated lithium perchlorate and aluminium. The underwater detonation of this explosive leads to the formation of a gaseous bubble essentially made of water vapor. In this paper, a brief detonating characterization of lithanol is presented using plates projection and cylinder raising up experiments. (J.S.) 5 refs.

  18. Half-Cell Law of Regular Cellular Detonations

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; JIANG Zong-Lin; GAO Yun-Liang

    2008-01-01

    Numerical simulations illustrate the half-cell law of regular cellular detonations propagating in confined space,i.e., the number of cells always maintains an integral multiple of half cell. The cells adapt themselves larger or smaller to the size of the unconfined space by maintaining the cell scale larger or smaller than the original cells of detonation.

  19. Detonation Diffraction in a Multi-Step Channel

    Science.gov (United States)

    2010-12-01

    section during a detonation. Shadowgraph setup utilizes an Ion Laser Technology Model 55001 Argon Ion laser emitting 750 mW beam at 488 nm passing...Rarefaction fan penetrating propagating a toward detonation axis (From [8... Solenoid Switches (lower section) (From [23]). ........ 39  Figure 29.  Sample Labview control panel

  20. Nano-scale spinning detonation in condensed phase energetic materials

    Science.gov (United States)

    Zhakhovsky, Vasily; Budzevich, Mikalai; Landerville, Aaron; White, Carter; Oleynik, Ivan

    2013-06-01

    Single- and multi-headed spinning detonation waves are observed in molecular dynamics simulations of a condensed phase detonation of an energetic material (EM) confined in round tubes of different radii. The EM is modeled using a modified AB Reactive Empirical Bond Order potential. The thermochemistry and reactive equation of state are varied by adjusting the barrier height for the exothermic reaction AB +B --> A +BB. This allows us to study the evolution of the detonation-wave structure as a function of physico-chemical properties of the AB explosive. The detonation wave is found to exhibit a pulsating planar front in a tube of 8 nm radius, which later collapses due to the development of longitudinal perturbations. Upon increase of the tube's radius to 16 nm, the detonation wave structure is stabilized through the development of a single-headed spinning detonation. The spinning detonation displays a four-wave configuration, including incident, oblique, transverse, and contact shock waves. The contact shock generated by a contact discontinuity is observed for the first time in our MD simulations. A multi-headed turbulent-like detonation structure develops within tubes of larger radii, and exhibit features similar to those observed in gases.

  1. Three dimensional hemispherical test development to evaluate detonation wave breakout

    Science.gov (United States)

    Francois, E. G.; Morris, J. S.; Lieber, M.

    2014-05-01

    The Onionskin test has been the standard test to evaluate detonation wave breakout over a hemispherical surface for decades. It has been an effective test used in a variety of applications to qualify main charge materials, evaluate different boosters, and compare different detonators. It is not without its shortfalls however. It only images a small portion of the explosive and requires very precise alignment and camera requirements to make sense of the results. Asymmetry in explosive behavior cannot be pinpointed or evaluated effectively. We have developed a new diagnostic using fiber optics covering the surface of the explosive to yield a 3D representation of the detonation wave behavior. Precise timing mapping of the detonation over the hemispherical surface is generated which can be converted to detonation wave breakout behavior using Huygens' wave reconstruction. This report will include the results of a recent suite of tests on PBX 9501, and discussion of how the test was developed for this explosive and contrasting previous work on PBX 9502. The results of these tests will describe the effects on detonation wave breakout symmetry when Sylgard 184 is placed between the detonator and booster. The effects on symmetry and timing when the Sylgard gap thickness is increased and the detonator is canted will be shown.

  2. 33 CFR 154.820 - Fire, explosion, and detonation protection.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fire, explosion, and detonation protection. 154.820 Section 154.820 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Systems § 154.820 Fire, explosion, and detonation protection. (a) A vapor control system with a...

  3. A note on the detonation of TNT

    Directory of Open Access Journals (Sweden)

    M. P. Murgai

    1953-01-01

    Full Text Available Whenever a non-reactive shock passes .through a system which is capable of undergoing an exothermic reaction, the high temperature and pressure in the shock front may start the chemical reaction, and it is possible that the heat evolved, under suitable conditions, map support the wave, and a self sustained stable shock propagate through the system. This shock wave maintained by the heat of the reaction constitutes a stable detonation wave. The equations of conservation of mass, momentum and energy, across the wave give the well known Rankine Huginiot equation. The formulation of an equation of state leaves the conditions behind the pure shook wave undetermined

  4. Progress of continuously rotating detonation engines

    Institute of Scientific and Technical Information of China (English)

    Zhou Rui; Wu Dan; Wang Jianping

    2016-01-01

    Continuously rotating detonation engine (CRDE) is a focus for concern in the field of aerospace propulsion. It has several advantages, including one-initiation, high thermal efficiency and simple structure. Due to these characteristics, it is expected to bring revolutionary advance-ments to aviation and aerospace propulsion systems and now has drawn much attention throughout the world. In this paper, an overview of the development of CRDE is given from several aspects:basic concepts, applications, experimental studies, numerical simulations, and so on. Representative results and outstanding contributions are summarized and the unresolved issues for further engi-neering applications of CRDE are provided.

  5. Progress of continuously rotating detonation engines

    Directory of Open Access Journals (Sweden)

    Zhou Rui

    2016-02-01

    Full Text Available Continuously rotating detonation engine (CRDE is a focus for concern in the field of aerospace propulsion. It has several advantages, including one-initiation, high thermal efficiency and simple structure. Due to these characteristics, it is expected to bring revolutionary advancements to aviation and aerospace propulsion systems and now has drawn much attention throughout the world. In this paper, an overview of the development of CRDE is given from several aspects: basic concepts, applications, experimental studies, numerical simulations, and so on. Representative results and outstanding contributions are summarized and the unresolved issues for further engineering applications of CRDE are provided.

  6. Semiautomatic MDF deburring tool. [Mild detonating fuse

    Energy Technology Data Exchange (ETDEWEB)

    Simonton, W.L.

    1976-03-31

    A device for semiautomatically deburring the ends of lengths of MDF (mild detonating fuse) was developed by the Automation Development group at Mound Laboratory. The device performs the deburring function by cutting a 0.002 in. x 0.002 in. chamfer on the MDF with small rotating blades. This air-operated, semiautomatic device provides improvement over the manual method of removing burrs by reduction in time and operator strain. A time study is underway to determine the time saved which is expected to be about 75 percent.

  7. Shock-to-Detonation Transition simulations

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  8. Benign concentric annular macular dystrophy

    Directory of Open Access Journals (Sweden)

    Luísa Salles de Moura Mendonça

    2015-06-01

    Full Text Available The purpose of the authors is to show clinical findings of a patient with benign concentric annular macular dystrophy, which is an unusual condition, and part of the "bull’s eye" maculopathy differential diagnosis. An ophthalmologic examination with color perception, fluorescein angiography, and ocular electrophysiology was performed.

  9. Effect of prill structure on detonation performance of ANFO

    Energy Technology Data Exchange (ETDEWEB)

    Salyer, Terry R [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory; Kiyanda, Charles B [Los Alamos National Laboratory; Morris, John S [Los Alamos National Laboratory; Zimmerly, Tony [EMRTC NMT

    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.

  10. Jaguar Procedures for Detonation Behavior of Explosives Containing Boron

    Science.gov (United States)

    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.

  11. Numerical investigation on evolution of cylindrical cellular detonation

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; JIANG Zong-lin; HU Zong-min; HAN Gui-lai

    2008-01-01

    Cylindrical cellular detonation is numerically investigated by solving twodimensional reactive Euler equations with a finite volume method on a two-dimensional self-adaptive unstructured mesh.The one-step reversible chemical reaction model is applied to simplify the control parameters of chemical reaction.Numerical results demonstrate the evolution of cellular cell splitting of cylindrical cellular detonation explored in experimentas.Split of cellular structures shows different features in the near-field and far-field from the initiation zone.Variation of the local curvature is a key factor in the behavior of cell split of cylindrical cellular detonation in propagation.Numerical results show that split of cellular structures comes from the self-organization of transverse waves corresponding to the development of small disturbances along the detonation front related to detonation instability.

  12. Evaluation of detonation energy from EXPLO5 computer code results

    Energy Technology Data Exchange (ETDEWEB)

    Suceska, M. [Brodarski Institute, Zagreb (Croatia). Marine Research and Special Technologies

    1999-10-01

    The detonation energies of several high explosives are evaluated from the results of chemical-equilibrium computer code named EXPLO5. Two methods of the evaluation of detonation energy are applied: (a) Direct evaluation from the internal energy of detonation products at the CJ point and the energy of shock compression of the detonation products, i.e. by equating the detonation energy and the heat of detonation, and (b) evaluation from the expansion isentrope of detonation products, applying the JWL model. These energies are compared to the energies computed from cylinder test derived JWL coefficients. It is found out that the detonation energies obtained directly from the energy of detonation products at the CJ point are uniformly to high (0.9445{+-}0.577 kJ/cm{sup 3}) while the detonation energies evaluated from the expansion isentrope, are in a considerable agreement (0.2072{+-}0.396 kJ/cm{sup 3}) with the energies calculated from cylinder test derived JWL coefficients. (orig.) [German] Die Detonationsenergien verschiedener Hochleistungssprengstoffe werden bewertet aus den Ergebnissen des Computer Codes fuer chemische Gleichgewichte genannt EXPLO5. Zwei Methoden wurden angewendet: (a) Direkte Bewertung aus der inneren Energie der Detonationsprodukte am CJ-Punkt und aus der Energie der Stosskompression der Detonationsprodukte, d.h. durch Gleichsetzung von Detonationsenergie und Detonationswaerme, (b) Auswertung durch die Expansions-Isentrope der Detonationsprodukte unter Anwendung des JWL-Modells. Diese Energien werden verglichen mit den berechneten Energien mit aus dem Zylindertest abgeleiteten JWL-Koeffizienten. Es wird gefunden, dass die Detonationsenergien, die direkt aus der Energie der Detonationsprodukte beim CJ-Punkt erhalten wurden, einheitlich zu hoch sind (0,9445{+-}0,577 kJ/cm{sup 3}), waehrend die aus der Expansions-Isentrope erhaltenen in guter Uebereinstimmung sind (0,2072{+-}0,396 kJ/cm{sup 3}) mit den berechneten Energien mit aus dem Zylindertest

  13. Thermonuclear detonations ensuing white dwarf mergers

    CERN Document Server

    Dan, Marius; Brüggen, Marcus; Ramirez-Ruiz, Enrico; Rosswog, Stephan

    2015-01-01

    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 type Ia supernova 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 several setups, guided by both merger remnants from our own simulations and by results taken from the literature. 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...

  14. Detonations in white dwarf dynamical interactions

    CERN Document Server

    Aznar-Siguán, Gabriela; Lorén-Aguilar, Pablo; José, Jordi; Isern, Jordi

    2013-01-01

    In old, dense stellar systems collisions of white dwarfs are a rather frequent phenomenon. Here we present the results of a comprehensive set of Smoothed Particle Hydrodynamics simulations of close encounters of white dwarfs aimed to explore the outcome of the interaction and the nature of the final remnants for different initial conditions. Depending on the initial conditions and the white dwarf masses, three different outcomes are possible. Specifically, the outcome of the interaction can be either a direct or a lateral collision or the interaction can result in the formation of an eccentric binary system. In those cases in which a collision occurs, the infalling material is compressed and heated such that the physical conditions for a detonation may be reached during the most violent phases of the merger. While we find that detonations occur in a significant number of our simulations, in some of them the temperature increase in the shocked region rapidly lifts degeneracy, leading to the quenching of the bu...

  15. Radioiodine therapy of benign thyroid disease; Radioiodbehandling af benign thyreoideasygdom

    Energy Technology Data Exchange (ETDEWEB)

    Krogh Rasmussen, Aa.; Jarloev, A.E.; Faber, J

    2000-01-01

    The aim of the study was to evaluate differences in the use of radioactive iodine in the treatment of benigh thyroid disease in Denmark. A questionnaire was distributed to all departments in Denmark which administer radioiodine in the treatment of benign thyroid disease (n=20). Radioiodine is used for patients with toxic nodular goitre and for patients with relapse of toxic diffuse goitre. Four departments did not use radioiodine for volume reduction in non-toxic goitre. Patient information's included very different recommendations regarding cautions in relation to radioiodine treatment. Radioiodine is widely used in the treatment of benign thyroid disease. We recommend a national standardization of the cautions in relation to radioiodine treatment. (au)

  16. Pulse Detonation Rocket MHD Power Experiment

    Science.gov (United States)

    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. Fatal tiger attack: a case report with emphasis on typical tiger injuries characterized by partially resembling stab-like wounds.

    Science.gov (United States)

    Pathak, Hrishikesh; Borkar, Jaydeo; Dixit, Pradeep; Dhawane, Shailendra; Shrigiriwar, Manish; Dingre, Niraj

    2013-10-10

    Fatalities due to attacks by tigers on humans are uncommon and are rarely described in the medico-legal literature. We herein present a forensic investigation in a unique case of a fatal tiger attack in the wild on a 35 year old female in India by an Indian Bengal tiger (Panthera tigris tigris). The attack resulted in two pairs of puncture wounds over the nape area with occult cervical spine injuries resulting from transfixing of spine due to the tiger canines; multiple puncture wounds, numerous scratches and abrasions consistent with the tiger claw injuries and injury to the right jugulocarotid vessels. This case outlines the characteristic injury pattern from such an attack along with the multiple sources of the tiger injuries. The analysis of these injuries might reveal the motivation behind the attack and the big cat species involved in the attack. A tiger injury is sometimes compared with a stab injury, as the patterned injuries due to a tiger bite are characterized by multiple penetrating, stab-like wounds. So, a special attention is paid toward establishment of the cause of death from bites by the animal teeth under unknown circumstances of trauma and to exclude the possibility of a homicide beyond reasonable doubt in such cases.

  18. Development of a chemical microthruster based on pulsed detonation

    Science.gov (United States)

    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.

  19. Optimum performance of explosives in a quasistatic detonation cycle

    Science.gov (United States)

    Baker, Ernest L.; Stiel, Leonard I.

    2017-01-01

    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 useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric 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. Detonation to the C-J point is found to result in the maximum net work in all cases.

  20. Effect of fuel stratification on detonation wave propagation

    Science.gov (United States)

    Masselot, Damien; Fievet, Romain; Raman, Venkat

    2016-11-01

    Rotating detonation engines (RDEs) form a class of pressure-gain combustion systems of higher efficiency compared to conventional gas turbine engines. One of the key features of the design is the injection system, as reactants need to be continuously provided to the detonation wave to sustain its propagation speed. As inhomogeneities in the reactant mixture can perturb the detonation wave front, premixed fuel jet injectors might seem like the most stable solution. However, this introduces the risk of the detonation wave propagating through the injector, causing catastrophic failure. On the other hand, non-premixed fuel injection will tend to quench the detonation wave near the injectors, reducing the likelihood of such failure. Still, the effects of such non-premixing and flow inhomogeneities ahead of a detonation wave have yet to be fully understood and are the object of this study. A 3D channel filled with O2 diluted in an inert gas with circular H2 injectors is simulated as a detonation wave propagates through the system. The impact of key parameters such as injector spacing, injector size, mixture composition and time variations will be discussed. PhD Candidate.

  1. Benign chondroblastoma - malignant radiological appearances

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, K.; Treugut, H.; Mueller, G.E.

    1980-04-01

    The very rare benign chondroblastoma occasionally invades soft tissues and may grow beyond the epiphysis into the metaphysis. In the present case such a tumour did not show the typical radiological appearances, but presented malignant features both on plain films and on the angiogram. The importance of biopsy of tumours which cannot be identified with certainty must be stressed before radical surgery is carried out.

  2. Detonation Propagation in 180°Ribs of an Insensitive High Energy Explosive

    Institute of Scientific and Technical Information of China (English)

    S. N. Lubyatinsky; A. Yu. Garmashev; V. G. Israelyan; O. V. Kostitsin; B. G. Loboiko; V. A. Pashentsev; V. A. Sibilev; E. B. Smirnov; V. P. Filin

    2004-01-01

    @@ Steady detonation regimes, such as the detonation of explosive rate sticks, are of particular interest in studies of explosive reaction kinetics. If this is the case the detonation front shape as well as the fields of particle velocity, pressure etc. are steady in the system of coordinates linked to the detonation front. This facilitates the analysis of the experimental data obtained to verify or calibrate various detonation models.

  3. Oblique detonation waves stabilized in rectangular-cross-section bent tubes

    OpenAIRE

    2011-01-01

    Oblique detonation waves, which are generated by a fundamental detonation phenomenon occurring in bent tubes, may be applied to fuel combustion in high-efficiency engines such as a pulse detonation engine (PDE) and a rotating detonation engine (RDE). The present study has experimentally demonstrated that steady-state oblique detonation waves propagated stably through rectangular-cross-section bent tubes by visualizing these waves using a high-speed camera and the shadowgraph method. The obliq...

  4. Detonation of the aluminized explosives with sodium azide

    Energy Technology Data Exchange (ETDEWEB)

    Maranda, A.; Nowaczewski, J.; Trzcinski, W. [Military University of Technology Kaliskiego, Warsaw (Poland)

    1996-12-31

    The velocity of detonation in the aluminized explosives containing sodium azide was measured. he experimental results were compared with those of calculation. Two different explosive components were used in the tests: RDX and ammonium nitrate. The contents of constituents of explosive mixture varied within a wide range. The X-ray analysis of the solid detonation products was also made. The results enable us to predict a behaviour of sodium azide and aluminium during detonation process of the explosive tested and to verify the possibility of reaction between aluminium and nitrogen during that process. (authors) 12 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Scott I [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory

    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.

  6. Detonation re-initiation mechanism following the Mach reflection of a quenched detonation

    CERN Document Server

    Bhattacharjee, Rohit; Maines, Geoffrey; Maley, Logan; Radulescu, Matei Ioan

    2012-01-01

    This experimental study addresses the re-initiation mechanism of detonation waves following the Mach reflection of a shock-flame complex. The detonation diffraction around a cylinder is used to reproducibly generate the shock-flame complex of interest. The experiments are performed in methane-oxygen. We use a novel experimental technique of coupling a two-in-line-spark flash system with a double-frame camera in order to obtain microsecond time resolution permitting accurate schlieren velocimetry. The first series of experiments compares the non-reactive sequence of shock reflections with the reflection over a rough wall under identical conditions. It was found that the hot reaction products generated along the rough wall are entrained by the wall jet into a large vortex structure behind the Mach stem. The second series of experiments performed in more sensitive mixtures addressed the sequence of events leading to the detonation establishment along the Mach and transverse waves. Following ignition and jet entr...

  7. Chapman-Jouguet deflagrations and their transition to detonation

    CERN Document Server

    Saif, Mohamed; Pekalski, Andrzej; Levin, Marc; Radulescu, Matei I

    2015-01-01

    We study experimentally fast flames and their transition to detonation in mixtures of methane, ethane, ethylene, acetylene, and propane mixtures with oxygen. Following the interaction of a detonation wave with a column of cylinders of varying blockage ratio, the experiments demonstrate that the fast flames established are Chapman-Jouguet deflagrations, in excellent agreement with the self-similar model of Radulescu et al. (2015). The experiments indicate that these Chapman-Jouguet deflagrations dynamically restructure and amplify into fewer stronger modes until the eventual transition to detonation. The transition length to a self-sustained detonation was found to correlate very well with the mixtures' sensitivity to temperature fluctuations, reflected by the $\\chi$ parameter introduced by Radulescu, which is the product of the non-dimensional activation energy $E_a/RT$ and the ratio of chemical induction to reaction time $t_i/t_r$. Correlation of the measured DDT lengths determined that the relevant characte...

  8. Qualitative modeling of the dynamics of detonations with losses

    KAUST Repository

    Faria, Luiz

    2015-01-01

    We consider a simplified model for the dynamics of one-dimensional detonations with generic losses. It consists of a single partial differential equation that reproduces, at a qualitative level, the essential properties of unsteady detonation waves, including pulsating and chaotic solutions. In particular, we investigate the effects of shock curvature and friction losses on detonation dynamics. To calculate steady-state solutions, a novel approach to solving the detonation eigenvalue problem is introduced that avoids the well-known numerical difficulties associated with the presence of a sonic point. By using unsteady numerical simulations of the simplified model, we also explore the nonlinear stability of steady-state or quasi-steady solutions. © 2014 The Combustion Institute.

  9. Theory of weakly nonlinear self-sustained detonations

    KAUST Repository

    Faria, Luiz M.

    2015-11-03

    We propose a theory of weakly nonlinear multidimensional self-sustained detonations based on asymptotic analysis of the reactive compressible Navier-Stokes equations. We show that these equations can be reduced to a model consisting of a forced unsteady small-disturbance transonic equation and a rate equation for the heat release. In one spatial dimension, the model simplifies to a forced Burgers equation. Through analysis, numerical calculations and comparison with the reactive Euler equations, the model is demonstrated to capture such essential dynamical characteristics of detonations as the steady-state structure, the linear stability spectrum, the period-doubling sequence of bifurcations and chaos in one-dimensional detonations and cellular structures in multidimensional detonations.

  10. Set-valued solutions for non-ideal detonation

    CERN Document Server

    Semenko, Roman; Kasimov, Aslan; Ermolaev, Boris

    2013-01-01

    The existence and structure of steady gaseous detonation propagating in a packed bed of solid inert particles are analyzed in the one-dimensional approximation by taking into consideration frictional and heat losses between the gas and the particles. A new formulation of the governing equations is introduced that eliminates the well-known difficulties with numerical integration across the sonic singularity in the reactive Euler equations. The new algorithm allows us to determine that the detonation solutions as the loss factors are varied have a set-valued nature at low detonation velocities when the sonic constraint disappears from the solutions. These set-valued solutions correspond to a continuous spectrum of the eigenvalue problem that determines the velocity of the detonation.

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

    Science.gov (United States)

    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.

  12. Jaguar Analyses of Experimental Detonation Values for Aluminized Explosives

    Science.gov (United States)

    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.

  13. Magnetohydrodynamic Augmentation of Pulse Detonation Rocket Engines (Preprint)

    Science.gov (United States)

    2010-09-28

    Detonation Rocket-Induced MHD Ejector (PDRIME) concept, energy could be extracted from the high speed portion of the system, e.g., through an MHD...but with some challenges associated with achieving these gains, suggesting further analysis and optimization are required. 15. SUBJECT TERMS 16...mentation, such as in the Pulse Detonation Rocket-Induced MHD Ejector (PDRIME) concept, energy could be extracted from the high speed por- tion of the system

  14. Numerical simulation of Mach reflection of cellular detonations

    Science.gov (United States)

    Li, J.; Lee, J. H. S.

    2016-09-01

    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. Detonation behavior of emulsion explosives sensitized with polymeric microballoons

    Science.gov (United States)

    Mendes, Ricardo; Ribeiro, José; Plaksin, Igor; Campos, José

    2013-06-01

    The differences between the detonation behavior of ammonium nitrate based emulsion explosive sensitized with polymeric or with glass microballoons is presented and discussed. Expancel® are hollow polymeric microballoons that contain a hydrocarbon gas. The mean particle size of those particles is 30 μm and their wall thickness is about 0.1 μm. The detonation velocity and the failure diameter of the emulsion explosive sensitized with different amounts of these particles were measured, in cylindrical charges, by ionization pins and optical fibers. The detonation velocity of emulsion explosives shows a non-monotonic evolution with the density with the maximum being reached far below the maximum density. The detonation fails when the density approaches the one of the matrix. The failure diameter increases with increasing density. For low densities the detonation velocity is almost independent of the charge diameter and it is close to the values predict by BKW EoS. The effect of the nature and size of the microballoons on the detonation front curvature and failure diameter was also determined.

  16. Non ideal detonation of emulsion explosives mixed with metal particles

    Science.gov (United States)

    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.

  17. A small-scale experiment using microwave interferometry to investigate detonation and shock-to-detonation transition in pressed TATB

    Science.gov (United States)

    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.

  18. Benign Papules and Nodules of Oral Mucosa

    Directory of Open Access Journals (Sweden)

    Mehmet Salih Gürel

    2012-12-01

    Full Text Available This article reviews some of the more common benign oral papules and nodules of oral mucosa with emphasis on their etiology, epidemiology, clinical presentation, histopathology, and treatment. These lesions include mucocele, traumatic fibroma, epulis, pyogenic granuloma, oral papilloma, oral warts, lymphangioma, hemangioma, lipoma, oral nevi and some soft tissue benign tumors. These benign lesions must be separated clinically and histologically from precancerous and malign neoplastic lesions. Accurate clinico-pathological diagnosis is mandatory to insure appropriate therapy.

  19. Detonation properties of 1,1-diamino-2,2-dinitroethene (DADNE).

    Science.gov (United States)

    Trzciński, Waldemar A; Cudziło, Stanisław; Chyłek, Zbigniew; Szymańczyk, Leszek

    2008-09-15

    1,1-Diamino-2,2-dinitroethene (DADNE, FOX-7) is an explosive of current interest. In our work, an advanced study of detonation characteristics of this explosive was performed. DADNE was prepared and recrystallized on a laboratory scale. Some sensitivity and detonation properties of DADNE were determined. The detonation performance was established by measurements of the detonation wave velocity, detonation pressure and calorimetric heat of explosion as well as the accelerating ability. The JWL (Jones-Wilkins-Lee) isentrope and the constant-gamma isentrope for the detonation products of DADNE were also found.

  20. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Reaugh, J E

    2011-11-22

    HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the response of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable

  1. TRENDS IN THE DEVELOPMENT OF DETONATION ENGINES FOR HIGH-SPEED AEROSPACE AIRCRAFTS AND THE PROBLEM OF TRIPLE CONFIGURATIONS OF SHOCK WAVES. Part I. Research of detonation engines

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2016-01-01

    Full Text Available We consider current problems of improving propulsion systems of highly supersonic air-space vehicles. In the first part, we review historic developments and list the landmark scientific papers. Classification of detonation engines is presented with detailed consideration of rotation detonation engines and continuous detonation engines. Experimental results on detonation, which are of particular importance for the design of detonation engines, are discussed. The second part of the paper provides an overview of the development in detonation theory, mathematical modelling, and numerical simulation. We focus on the interference of shock waves with formation of triple points, regular and irregular reflection of shock waves, existence of multiple solutions and the resulting appearance of hysteresis. The relevance and importance of triple shock wave configurations for the development of new types of air intakes and detonation jet engines is demonstrated.

  2. Detonation Structure Under Chain Branching Kinetics

    Science.gov (United States)

    Liang, Z.; Bauwens, L.

    2006-07-01

    Hydrogen-oxygen chemistry is characterized by a chain branching mechanism that yields three explosion limits. While a detailed kinetic scheme appropriate for hydrogen-oxygen should produce correct results, in many circumstances, a simpler yet reasonably realistic model will be warranted. In particular, it is easier to develop a clear understanding of the reaction zone structure using a simpler model, that includes only the key mechanisms. To that effect, we consider a four-step chain branching scheme that exhibits an explosion behavior with three limits, which behaves at least qualitatively like hydrogen chemistry. We focus in particular on the structure of the initiation and chain branching zones, using a combination between numerical simulation and analysis. Numerical simulations using this chemical model show distinctive keystone figures in the flow field, close to observations in hydrogen-oxygen detonation experiments. The structure of the chain branching zone is resolved using a perturbation analysis, which clarifies the differences between explosion and no-explosion regions and allows for an evaluation of the induction length in the steady wave. The analysis assumes both high activation energy and a slow initiation. Three cases are identified, respectively, with pressure and temperature located within the explosion region, close to the explosion limit and within the no-explosion region. The induction length is shorter and the reaction rate is faster by several orders of magnitude in the explosion region.

  3. Detonation Type Ram Accelerator: A Computational Investigation

    Directory of Open Access Journals (Sweden)

    Sunil Bhat

    2000-01-01

    Full Text Available An analytical model explaining the functional characteristics of detonation type ram accelerator is presented. Major flow processes, namely, (i supersonic flow over the cone of the projectile, (ii initiation ofconical shock wave and its reflection from the tube wall, (iii supersonic combustion, and (iv expansion wave and its reflection are modelled. Taylor-Maccoll approach is adopted for modellingthe flow over the cone of the projectile. Shock reflection is treated in accordance with wave angle theorytor flows over the wedge. Prandtl-Mayer analysis is used to model the expansion wave and its reflection.Steady one-dimensional flow with heat transfer along with Rayleigh line equation for perfect gases isused to model supersonic combustion. A computer code is developed to compute the thrust producedby combustion of gases. Ballistic parameters like thrust-pressure ratio and ballistic efficiency of the accelerator are evaluated and their maximum values are 0.032 and 0.068, respectively. The code indicates possibility ofachieving high velocity of 7 km/s on utilising gaseous mixture of 2H2+O2 in the operation.Velocity range suitable for operation of the accelerator lies between 3.8 - 7.0 km/s. Maximum thrust valueis 33721 N which corresponds to the projectile velocity of 5 km/s.

  4. Numerical simulation of detonation failure in nitromethane

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Color camera pyrometry for high explosive detonations

    Science.gov (United States)

    Densmore, John; Biss, Matthew; Homan, Barrie; McNesby, Kevin

    2011-06-01

    Temperature measurements of high-explosive and combustion processes are difficult because of the speed and environment of the events. We have characterized and calibrated a digital high-speed color camera that may be used as an optical pyrometer to overcome these challenges. The camera provides both high temporal and spatial resolution. The color filter array of the sensor uses three color filters to measure the spectral distribution of the imaged light. A two-color ratio method is used to calculate a temperature using the color filter array raw image data and a gray-body assumption. If the raw image data is not available, temperatures may be calculated from processed images or movies depending on proper analysis of the digital color imaging pipeline. We analyze three transformations within the pipeline (demosaicing, white balance, and gamma-correction) to determine their effect on the calculated temperature. Using this technique with a Vision Research Phantom color camera, we have measured the temperature of exploded C-4 charges. The surface temperature of the resulting fireball rapidly increases after detonation and then decayed to a constant value of approximately 1980 K. Processed images indicates that the temperature remains constant until the light intensity decreased below the background value.

  6. Reducing the Consequences of a Nuclear Detonation.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Benign communicating hydrocephalus in children

    Energy Technology Data Exchange (ETDEWEB)

    Kendall, B.; Holland, I.

    1981-03-01

    A review was performed of the computed tomograms (CTs) of 500 children which had been reported as showing widening of the supratentorial subarachnoid spaces with normal cerebral substance. On the basis of this a radiological diagnosis of cerebral atrophy had been made in all but five, who were said to have mengalencephaly. From these, the children with large or abnormally enlarging heads, but normal or only slightly enlarged ventricles, were selected; there were 40 such cases (8%). The clinical condition either improved or remained stable over a period of 2 years; in the majority the scan abnormality regressed (22.5%) or remained static (67.5%). In three cases there was slight progression of the CT changes before stabilisation, but only one case developed classical communicating hydrocephalus necessitating a shunt procedure. This condition is a generally benign and mild form of communicating hydrocephalus, for which an aetiological factor was apparent in about two-thirds of the cases studied.

  8. Benign paroxysmal torticollis in infancy

    Directory of Open Access Journals (Sweden)

    Dimitrijević Lidija

    2006-01-01

    Full Text Available Background. Benign paroxysmal torticollis (BPT is an episodic functional disorder of unknown etiology, characterized by the periods of torticollic posturing of the head, that occurs in the early months of life in healthy children. Case report. We reported two patients with BPT. In the first patient the symptoms were observed at the age of day 20, and disappeared at the age of 3 years. There were 10 episodes, of which 2 were followed by vomiting, pallor, irritability and the abnormal trunk posture. In the second patient, a 12-month-old girl, BPT started from day 15. She had 4 episodes followed by vomiting in the first year. Both girls had the normal psychomotor development. All diagnostical tests were normal. Conclusion. The recognition of BPT, as well as its clinical course may help to avoid not only unnecessary tests and the treatment, but also the anxiety of the parents.

  9. Benign fibroxanthoma of the mandible

    Directory of Open Access Journals (Sweden)

    L Zouloumis

    2011-01-01

    Full Text Available Histiocytomas constitute a large group of tumors, the classification of which created a lot of confusion in the past. For this reason, various attempts were carried out during the last years so that a widely accepted classification system could be defined. Fibroxanthomas, according to contemporary data, are classified into benign histiocytomas and they are mostly located at the skin of extremities. They are rarely localized in the area of the head and neck, where they are found commonly in soft tissue. Fibroxanthomas located at the bones of oral and maxillofacial region are extremely rare. The purpose of this paper is to present a case of a fibroxanthoma located at the mandible as well as to analyze the histological findings of the lesion on which the diagnosis and differential diagnosis were based.

  10. Non ideal detonation of emulsion explosives mixed with metal particles

    Science.gov (United States)

    Mendes, Ricardo; Ribeiro, José B.; Plaksin, I.; Campos, Jose

    2012-03-01

    The detonation of ammonium nitrate based compositions like emulsion explosives mixed with metal particles was experimentally investigated. Aluminum powder with a mean particle size of 6 μm was used, and the mass concentration of aluminum on the explosive charge ranged from 0 to 30% wt. The values of the detonation velocity, the pressure attenuation - P(x) - of the shock 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 pressuretimes 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 allows a quasicontinuous evaluation of the detonation wave run propagation and the assessment of spatial resolved measurements of the shock wave induced in the PMMA barrier. Results of that characterization process are presented and discussed for aluminized and non-aluminized emulsion explosives. The experimental results have shown that the detonation velocity decreases monotonically with the increase of aluminum content. Nevertheless the peak of detonation pressure profiles presents a non-monotonic behavior increasing its value up to an Al content of 20% wt, after which it starts to decrease.

  11. Helium in Double-Detonation Models of Type Ia Supernovae

    CERN Document Server

    Boyle, Aoife; Hachinger, Stephan; Kerzendorf, Wolfgang

    2016-01-01

    The double-detonation explosion model has been considered a candidate for explaining astrophysical transients with a wide range of luminosities. In this model, a carbon-oxygen white dwarf star explodes following detonation of a surface layer of helium. One potential signature of this explosion mechanism is the presence of unburned helium in the outer ejecta, left over from the surface helium layer. In this paper we present simple approximations to estimate the optical depths of important He I lines in the ejecta of double-detonation models. We use these approximations to compute synthetic spectra, including the He I lines, for double-detonation models obtained from hydrodynamical explosion simulations. Specifically, we focus on photospheric-phase predictions for the near-infrared 10830 \\AA~and 2 $\\mu$m lines of He I. We first consider a double detonation model with a luminosity corresponding roughly to normal SNe Ia. This model has a post-explosion unburned He mass of 0.03 $M_{\\odot}$ and our calculations sug...

  12. Dynamics of detonations with a constant mean flow divergence

    CERN Document Server

    Borzou, Bijan

    2016-01-01

    The present work addresses the question of whether mean field macroscopic models are suitable to describe the dynamics of real cellular detonations. This question is posed in the framework of detonations with stream-tube area divergence that is kept constant, as to generate attenuated detonations in quasi-steady state. An exponential horn geometry is used, in order to keep the source term due to geometrical divergence constant in the governing equations of mean flow, and hence permit to establish steady travelling waves with constant losses. The experiments were conducted in two mixtures 2C$_2$H$_2$+5O$_2$+21Ar, characterized by a relatively weak instability, and C$_3$H$_8$+5O$_2$, characterized by a much more unstable cellular structure. The experiments demonstrated that such quasi-steady state detonations can be realized. The experiments permitted a unique detonation speed - divergence scaling laws to be developed. Quantitative comparisons were made with steady wave predictions based on the underlying chemi...

  13. Investigations on detonation shock dynamics and related topics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, D.S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Theoretical and Applied Mechanics

    1993-11-01

    This document is a final report that summarizes the research findings and research activities supported by the subcontract DOE-LANL-9-XG8-3931P-1 between the University of Illinois (D. S. Stewart Principal Investigator) and the University of California (Los Alamos National Laboratory, M-Division). The main focus of the work has been on investigations of Detonation Shock Dynamics. A second emphasis has been on modeling compaction of energetic materials and deflagration to detonation in those materials. The work has led to a number of extensions of the theory of Detonation Shock Dynamics (DSD) and its application as an engineering design method for high explosive systems. The work also enhanced the hydrocode capabilities of researchers in M-Division by modifications to CAVEAT, an existing Los Alamos hydrocode. Linear stability studies of detonation flows were carried out for the purpose of code verification. This work also broadened the existing theory for detonation. The work in this contract has led to the development of one-phase models for dynamic compaction of porous energetic materials and laid the groundwork for subsequent studies. Some work that modeled the discrete heterogeneous behavior of propellant beds was also performed. The contract supported the efforts of D. S. Stewart and a Postdoctoral student H. I. Lee at the University of Illinois.

  14. Benign paroxysmal positional vertigo in Parkinson's disease

    NARCIS (Netherlands)

    Wensen, E. van; Leeuwen, R.B. van; Zaag-Loonen, H.J. van der; Masius-Olthof, S.; Bloem, B.R.

    2013-01-01

    BACKGROUND: Dizziness is a frequent complaint of patients with Parkinson's disease (PD), and orthostatic hypotension (OH) is often thought to be the cause. We studied whether benign paroxysmal positional vertigo (BPPV) could also be an explanation. AIM: To assess the prevalence of benign paroxysmal

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

    Science.gov (United States)

    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.

  16. Undetected Aorto-RV Fistula With Aortic Valve Injury and Delayed Cardiac Tamponade following a Chest Stab Wound: A Case Report

    Directory of Open Access Journals (Sweden)

    Jamil Esfahanizadeh

    2013-06-01

    Full Text Available Introduction: Although a few patients will survive after penetrating cardiac injuries, some of them may have unnoticeable intracardiac injuries. The combination of aorto-right ventricular fistula with aortic valve injury is rare.Case Presentation: A 19 year-old man referred with an aorto-right ventricular fistula accompanied with aortic regurgitation and delayed tamponade following a stab in the chest. The patient was scheduled for fistula repair, aortic valve replacement and pericardectomy two months after trauma.Conclusions: To prevent missing intracardiac injury and also late cardiac injury complications, in all pericordial stab wounds, serial clinical examinations and serial echocardiography should be performed. In addition, cardiac injuries should be repaired during the same hospital stay.

  17. Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs

    Science.gov (United States)

    2013-03-01

    TP-2013-011 Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs Distribution A: Approved for public release...Detonation Fireballs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) W.K. Lewis1, C.G. Rumchik2, M.J...detonation fireballs that form as under- oxidized detonation products burn in the surrounding air are optically dense and the corresponding emission

  18. Effect of detonation nanodiamonds on phagocyte activity.

    Science.gov (United States)

    Karpukhin, Alexey V; Avkhacheva, Nadezhda V; Yakovlev, Ruslan Yu; Kulakova, Inna I; Yashin, Valeriy A; Lisichkin, Georgiy V; Safronova, Valentina G

    2011-07-01

    Detonation ND (nanodiamond) holds much promise for biological studies and medical applications. Properties like size of particles, inclination for modification of their surface and unambiguous biocompatibility are crucial. Of prime importance is interaction between ND and immune cells, which supervise foreign intrusion into an organism and eliminate it. Neutrophils are more reactive in inflammatory response implementing cytotoxical arsenal including ROS (reactive oxygen species). The aim of the work was to estimate the ability of two ND samples (produced by Diamond Center and PlasmaChem) to keep the vitality of neutrophils from the inflammatory site. The ability of cells to generate ROS in the presence of ND particles is considered as indicating their biocompatibility. IR spectra and size of particles in the samples were characterized. Acid modification of ND was carried out to get the luminescent form. In the biological aspect, ND demonstrated up or down action, depending on the concentration, time and conditions of activation of cells. Weak action of ND in whole blood was obtained possibly owing to the ND adsorbed plasma proteins, which mask active functional groups to interact with the cell membrane. ND did not influence the viability of isolated inflammatory neutrophils in low and moderate concentrations and suppressed it in high concentrations (≥1 g/l). Addition of ND to the cell suspension initiated concentration-dependent reaction to produce ROS similar to respiratory burst. ND up-regulated response to bacterial formylpeptide, but up- and down-modified (low or high concentrations, accordingly) response to such bacterial agents as OZ (opsonized zymosan), which neutrophils swallow up by oxygen-dependent phagocytosis. Localization of the particles on the cell surface as into the cells was identified by monitoring the intrinsic fluorescence of oxidized ND. The various mechanisms that could account for penetration of ND particles into the cell are discussed

  19. Full-Length Genome Sequence of Type M/emm83 Group A Streptococcus pyogenes Strain STAB1101, Isolated from Clustered Cases in Brittany.

    Science.gov (United States)

    Soriano, Nicolas; Vincent, Pascal; Auger, Gabriel; Cariou, Marie-Estelle; Moullec, Séverine; Lagente, Vincent; Ygout, Jean-François; Kayal, Samer; Faili, Ahmad

    2015-01-22

    Here, we announce the complete annotated genome sequence of a Streptococcus pyogenes M/emm83 strain, STAB1101, isolated from clustered cases in homeless persons in Brittany (France). The genome is composed of 1,709,790 bp, with a G+C content of 38.4% and 1,550 identified coding sequences (CDS), and it harbors a Tn916-like transposon.

  20. Gasdynamic characteristics of toroidal shock and detonation wave converging

    Institute of Scientific and Technical Information of China (English)

    TENG; Honghui; JIANG; Zonglin

    2005-01-01

    The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

  1. Mathematical modeling of detonation initiation via flow cumulation effects

    Science.gov (United States)

    Semenov, I.; Utkin, P.; Akhmedyanov, I.

    2016-07-01

    The paper concerns two problems connected with the idea of gaseous detonation initiation via flow cumulation effects and convergence of relatively weak shock waves (SW). The first one is the three-dimensional (3D) numerical investigation of shock-to-detonation transition (SDT) in methane-air mixture in a tube with parabolic contraction followed by the tube section of narrow diameter and conical expansion. The second problem is the numerical study of the start-up of the model small-scale hydrogen electrochemical pulse detonation engine with the use of electrical discharge generating the toroidal SW. The investigation is performed by means of numerical simulation with the use of modern high-performance computing systems.

  2. Velocity of detonation (VOD measurement techniques - practical approach

    Directory of Open Access Journals (Sweden)

    Aruna Dhanraj Tete

    2013-06-01

    Full Text Available Velocity of Detonation (VOD is an important measure characteristics parameter of explosive material. The performance of explosive invariably depends on the velocity of detonation. The power/ strength of explosive to cause fragmentation of the solid structure determine the efficiency of the Blast performed. It is an established fact that measuring velocity of detonation gives a good indication of the strength and hence the performance of the explosive. In this survey various VOD measurement techniques such as electric, nonelectric and fibre optic have been discussed. To aid the discussion some commercially available VOD meter comparison are also presented. After review of the existing units available commercially and study of their respective merits and demerits, feature of an ideal system is proposed. 

  3. Influence of Accelerated Aging on Detonation Performance of Explosives

    Institute of Scientific and Technical Information of China (English)

    GAO Da-yuan; HUA Cheng; WANG Xiang; HAN Yong

    2010-01-01

    To understand the aging effects on detonation performances of explosives, an accelerated aging mechanism and effect of explosives were analyzed. Based on the thermo-gravimetric (TG) curves of explosives under the heat rate of 5, 10 and 20 K·min-1, the thermal decomposition activation energy, pre-exponential factor, mechanism function and kinetic equation of the explosives were calculated by Ozawa's equation and decomposition extents. Then, according to the derived kinetic equation, the density, composition and heat of formation of GI-1, PBX-1 and PBX-2 explosive in different decompo-sition extents were calculated at accelerated aging temperatures of 70 ℃ and 75 ℃, respectively. Furthermore, the detona-tion parameters of GI-1, PBX-1 and PBX-2 explosives were found out by means of VLWR code. The results show that after accelerated aging, the density are decrease, the detonation velocity and pressure are all decreased slightly.

  4. The analysis of thermal stability of detonation nanodiamond

    Science.gov (United States)

    Efremov, V. P.; Zakatilova, E. I.

    2016-11-01

    The detonation nanodiamond is a new perspective material. Ammunition recycling with use of high explosives and obtaining nanodiamond as the result of the detonation synthesis have given a new motivation for searching of their application areas. In this work nanodiamond powder has been investigated by the method of synchronous thermal analysis. Experiments have been carried out at atmospheric pressure in the environment of argon. Nanodiamond powder has been heated in the closed corundum crucible at the temperature range of 30-1500 °C. The heating rates were varied from 2 K/min to 20 K/min. After the heat treatment, the samples have been studied by the x-ray diffraction and the electron microscopy. As one of the results of this work, it has been found that the detonation nanodiamond has not started the transition into graphite at the temperature below 800 °C.

  5. Detonation wave driven by condensation of supersaturated carbon vapor.

    Science.gov (United States)

    Emelianov, A; Eremin, A; Fortov, V; Jander, H; Makeich, A; Wagner, H Gg

    2009-03-01

    An experimental observation of a detonation wave driven by the energy of condensation of supersaturated carbon vapor is reported. The carbon vapor was formed by the thermal decay of unstable carbon suboxide C3O2 behind shock waves in mixtures containing 10-30% C3O2 in Ar. In the mixture 10% C3O2+Ar the insufficient heat release resulted in a regime of overdriven detonation. In the mixture 20% C3O2+Ar measured values of the pressure and wave velocity coincident with calculated Chapman-Jouguet parameters were attained. In the richest mixture 30% C3O2+Ar an excess heat release caused the slowing down of the condensation rate and the regime of underdriven detonation was observed.

  6. Ferrite core coupled slapper detonator apparatus and method

    Science.gov (United States)

    Boberg, Ralph E.; Lee, Ronald S.; Weingart, Richard C.

    1989-01-01

    Method and apparatus are provided for coupling a temporally short electric power pulse from a thick flat-conductor power cable into a thin flat-conductor slapper detonator circuit. A first planar and generally circular loop is formed from an end portion of the power cable. A second planar and generally circular loop, of similar diameter, is formed from all or part of the slapper detonator circuit. The two loops are placed together, within a ferrite housing that provides a ferrite path that magnetically couples the two loops. Slapper detonator parts may be incorporated within the ferrite housing. The ferrite housing may be made vacuum and water-tight, with the addition of a hermetic ceramic seal, and provided with an enclosure for protecting the power cable and parts related thereto.

  7. Mechanisms of direct detonation initiation via thermal explosion of radiatively heated gas-particles layer

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    Conceptual approach of detonation wave direct initiation by external radiative heating of microparticles locally suspended in flammable gaseous mixture is proposed. Combustion waves and detonation initiation mechanisms in the congestion regions of microparticles heated by radiation are studied numerically. Necessary criteria on geometrical scales of gas-particles layer and spatial uniformity of particles distribution for successful detonation initiation are formulated.

  8. Reproducibility Distinguishability and Correlation of Fireball and Shockwave Dynamics in Explosive Munitions Detonations

    Science.gov (United States)

    2006-03-01

    plots, heat of detonation (which follows the same correlation as the specific afterburn energy) initial mass in the lower plots. As all quantities...fireball area increases with the third power of the heat of detonation , neglecting the outliers...third power of the heat of detonation , neglecting the outliers. In all cases, correlation is higher than when C-4 was included

  9. Comparison Of Flat-Knitted Structures Made Of Poly(P-Phenylene-2,6-Benzobisoxazole) And Para-Aramid Referring To Their Stab Resistance

    Science.gov (United States)

    Obermann, M.; Aumann, S.; Heimlich, F.; Weber, M. O.; Schwarz-Pfeiffer, A.

    2016-07-01

    In the field of protective gear, developers always aim for lighter and more flexible material in order to increase the wearing comfort. Suppliers now work on knitted garments in the sports-sector as well as in workwear and protective gear for policemen or security-agents. In a recent project different knitted structures made of a poly(p-phenylene-2,6-benzobisoxazole) (PBO)-multifilament were compared to their counterparts made of para-aramid. In focus of the comparison stood the stab-resistance linked to either the mass per unit area or the stitch density. The tested fabrics were produced on hand flat knitting machines as well as on electronical flat knitting machines of the type Stoll CMS 330TC4, in order to analyse fabrics with different tightness factor and machine gauges. The stab resistance of the different knitted fabrics was examined according to the standard of the Association of Test Laboratories for Bullet, Stab or Pike Resistant Materials and Construction Standards. The presentation includes the depiction of the results of the test series and their interpretation. Furthermore it will give an outlook on most suitable combinations of materials and structures to be used in protective gear.

  10. Can Deflagration-Detonation-Transitions occur in Type Ia Supernovae?

    CERN Document Server

    Niemeyer, J C

    1999-01-01

    The mechanism for deflagration-detonation-transition (DDT) by turbulent preconditioning, suggested to explain the possible occurrence of delayed detonations in Type Ia supernova explosions, is argued to be conceptually inconsistent. It relies crucially on diffusive heat losses of the burned material on macroscopic scales. Regardless of the amplitude of turbulent velocity fluctuations, the typical gradient scale for temperature fluctuations is shown to be the laminar flame width or smaller, rather than the factor of thousand more required for a DDT. Furthermore, thermonuclear flames cannot be fully quenched in regions much larger than the laminar flame width as a consequence of their simple ``chemistry''. Possible alternative explosion scenarios are briefly discussed.

  11. Rotating Detonation Combustion: A Computational Study for Stationary Power Generation

    Science.gov (United States)

    Escobar, Sergio

    The increased availability of gaseous fossil fuels in The US has led to the substantial growth of stationary Gas Turbine (GT) usage for electrical power generation. In fact, from 2013 to 2104, out of the 11 Tera Watts-hour per day produced from fossil fuels, approximately 27% was generated through the combustion of natural gas in stationary GT. The thermodynamic efficiency for simple-cycle GT has increased from 20% to 40% during the last six decades, mainly due to research and development in the fields of combustion science, material science and machine design. However, additional improvements have become more costly and more difficult to obtain as technology is further refined. An alternative to improve GT thermal efficiency is the implementation of a combustion regime leading to pressure-gain; rather than pressure loss across the combustor. One concept being considered for such purpose is Rotating Detonation Combustion (RDC). RDC refers to a combustion regime in which a detonation wave propagates continuously in the azimuthal direction of a cylindrical annular chamber. In RDC, the fuel and oxidizer, injected from separated streams, are mixed near the injection plane and are then consumed by the detonation front traveling inside the annular gap of the combustion chamber. The detonation products then expand in the azimuthal and axial direction away from the detonation front and exit through the combustion chamber outlet. In the present study Computational Fluid Dynamics (CFD) is used to predict the performance of Rotating Detonation Combustion (RDC) at operating conditions relevant to GT applications. As part of this study, a modeling strategy for RDC simulations was developed. The validation of the model was performed using benchmark cases with different levels of complexity. First, 2D simulations of non-reactive shock tube and detonation tubes were performed. The numerical predictions that were obtained using different modeling parameters were compared with

  12. Curved detonation fronts in solid explosives: Collisions and boundary interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bdzil, J.B. [Los Alamos National Lab., NM (United States); Aslam, T.D.; Stewart, D.S. [Univ. of Illinois, Urbana, IL (United States). TAM Dept.

    1995-09-01

    Detonation Shock Dynamics (DSD) can be used to model the effects that shock curvature, {kappa}, has oil detonation speed, D{sub n}({kappa}). At the edges of the explosive, D{sub n}({kappa}) is supplemented with boundary conditions. By direct numerical simulation (DNS). The authors study how the reaction zone interacts with the edge. DSD theory has been integrated with the level-set method of Osher and Sethian and the Los Alamos DNS code Mesa to create a powerful tool for simulating complex explosive containing systems.

  13. The equation of state of predominant detonation products

    Science.gov (United States)

    Zaug, Joseph; Crowhurst, Jonathan; Bastea, Sorin; Fried, Laurence

    2009-06-01

    The equation of state of detonation products, when incorporated into an experimentally grounded thermochemical reaction algorithm can be used to predict the performance of explosives. Here we report laser based Impulsive Stimulated Light Scattering measurements of the speed of sound from a variety of polar and nonpolar detonation product supercritical fluids and mixtures. The speed of sound data are used to improve the exponential-six potentials employed within the Cheetah thermochemical code. We will discuss the improvements made to Cheetah in terms of predictions vs. measured performance data for common polymer blended explosives. Accurately computing the chemistry that occurs from reacted binder materials is one important step forward in our efforts.

  14. Nocturia and benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    Laketić Darko

    2008-01-01

    Full Text Available Background/Aim. Nocturia often occurs in patients with benign prostate hyperplasia (BPH. The aim of the study was to investigate the frequency of nocturia in patients with BPH. Nocturia and other factors associated with it were also investigated. Methods. Forty patients with the confirmed diagnosis of BPH were studied. Transurethral and transvesical prostatectomy were performed in all the patients. Symptoms were evaluated with the International Prostate Symptom Score before, as well as three and six months after the surgery. All the results were compared with the control group. Results. There was no statistically significant difference between the patients before and after the surgery regarding nocturia. There was, however, a statistically significant difference between the operated patients and the control group regarding nocturia, as well as a statistically significant correlation between noctruia and the age of the patients in both the investigated and the control group. A correlation also existed between nocturia and the prostatic size. Conclusion. There was no statistically significant improvement in symptoms of nocturia after the surgery. It is necessary to be very careful in decision making in patients with nonabsolute indiction for surgery and isolated bothersome symptom of nocturia. Age of a patient should also be considered in the evaluation of favorable result of the surgery because of a significant correlation between noctura and the age of a patient.

  15. The Detonation Mechanism of the Pulsationally-Assisted Gravitationally-Confined Detonation Model of Type Ia Supernovae

    CERN Document Server

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

    2012-01-01

    We describe the detonation mechanism comprising the "Pulsationally Assisted" Gravitationally Confined Detonation (GCD) model of Type Ia supernovae (SNe Ia). This model is analogous to the previous GCD model reported in Jordan (2008); however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final energy releases and nickel-56 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 initia...

  16. BENIGN INTRACRANIAL HYPOTENSION WITH INCIDENTAL PARASAGITTAL MENINGIOMA

    Directory of Open Access Journals (Sweden)

    Sukumar

    2015-12-01

    Full Text Available Benign intracranial hypotension, otherwise called as idiopathic intracranial hypotension is caused by CSF leaks due to disruption in spinal meninges. It is most commonly caused by disruption and leak at cervical and thoracic spine. Imaging is sometimes the most important key to the diagnosis of idiopathic intracranial hypotension, which helps in appropriate treatment of the patient. Here, we are presenting a case of benign intracranial hypotension associated with incidental parasagittal meningioma. The presence of benign intracranial hypotension was confirmed by taking MR myelogram.

  17. The development and testing of pulsed detonation engine ground demonstrators

    Science.gov (United States)

    Panicker, Philip Koshy

    2008-10-01

    The successful implementation of a PDE running on fuel and air mixtures will require fast-acting fuel-air injection and mixing techniques, detonation initiation techniques such as DDT enhancing devices or a pre-detonator, an effective ignition system that can sustain repeated firing at high rates and a fast and capable, closed-loop control system. The control system requires high-speed transducers for real-time monitoring of the PDE and the detection of the detonation wave speed. It is widely accepted that the detonation properties predicted by C-J detonation relations are fairly accurate in comparison to experimental values. The post-detonation flow properties can also be expressed as a function of wave speed or Mach number. Therefore, the PDE control system can use C-J relations to predict the post-detonation flow properties based on measured initial conditions and compare the values with those obtained from using the wave speed. The controller can then vary the initial conditions within the combustor for the subsequent cycle, by modulating the frequency and duty cycle of the valves, to obtain optimum air and fuel flow rates, as well as modulate the energy and timing of the ignition to achieve the required detonation properties. Five different PDE ground demonstrators were designed, built and tested to study a number of the required sub-systems. This work presents a review of all the systems that were tested, along with suggestions for their improvement. The PDE setups, ranged from a compact PDE with a 19 mm (3/4 in.) i.d., to two 25 mm (1 in.) i.d. setups, to a 101 mm (4 in.) i.d. dual-stage PDE setup with a pre-detonator. Propane-oxygen mixtures were used in the smaller PDEs. In the dual-stage PDE, propane-oxygen was used in the pre-detonator, while propane-air mixtures were used in the main combustor. Both rotary valves and solenoid valve injectors were studied. The rotary valves setups were tested at 10 Hz, while the solenoid valves were tested at up to 30 Hz

  18. The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity.

    Science.gov (United States)

    Kimura, Kazuki; Chiba, Satoshi

    2015-04-07

    Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals.

  19. The stabbing of Amelia (or how was extinguished the married women discrimination from the argentinian telephone service

    Directory of Open Access Journals (Sweden)

    Dora Barrancos

    2008-04-01

    Full Text Available This paper highlights the tracks of Amelia C. Her life story as switchboard is relevant to understand the women' s discrimination in laboral market in the early twentieth century. This article will be focused on the marital satatus as pattern of female exclusion. The strategy used by Amelia against that pattern, although individual and even desperate, detonated a series of revisions of existing legislation that were supported by different groups in society. The corpus is based on records of the telephone company in which Amelia was employed for several years and the impact of their strategies in the local press.

  20. Horizontal Canal Benign Positional Vertigo

    Directory of Open Access Journals (Sweden)

    Mohtaram Najafi

    1998-03-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV is a syndrome characterized by transient episodes of vertigo in association with rapid changes in head position in Dix-Halpike Maneuver. This kind of vertigo is thought to be caused by migration of otoconial debris into canals other than the posterior canal, such as the anterior or lateral canals. It is also theoretically possible for many aberrant patterns of BPPV to occur from an interaction of debris in several canals, location of debris within the canal, and central adaptation patterns to lesions. The symptoms of BPPV are much more consistent with free-moving densities (canaliths in the posterior SCC rather than fixed densities attached to the cupula. While the head is upright, the particles sit in the PSC at the most gravity-dependent position. The best method to induce and see vertigo and nystagmus in BPPV of the lateral semicircular canal is to rotate head 90°while patient is in the supine position, nystagmus would appear in the unaffected side weaker but longer than the affected side. canal paresis has been described in one third of the patients with BPPV. Adaptation which is one of the remarkable features of BPPV in PSC is rarely seen in LSC. Rotations of 270° or 360° around the yaw axis (the so-called barbecue maneuver toward the unaffected ear are popular methods for the treatment of geotropic HC-BPPV. These maneuvers consist of sequential head turning of 90° toward the healthy side while supine. With these maneuvers, the free-floating otoconial debris migrates in the ampullofugal direction, finally entering the utricle through the nonampullated end of the horizontal canal. This kind of vertigo recovers spontaneously more rapidly and suddenly.

  1. Oxidative stress in benign prostate hyperplasia.

    Science.gov (United States)

    Zabaiou, N; Mabed, D; Lobaccaro, J M; Lahouel, M

    2016-02-01

    To assess the status of oxidative stress in benign prostate hyperplasia, a very common disease in older men which constitutes a public health problem in Jijel, prostate tissues were obtained by transvesical adenomectomy from 10 men with benign prostate hyperplasia. We measured the cytosolic levels of malondialdehyde (MDA) and glutathione (GSH) and cytosolic enzyme activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase. The development of benign prostate hyperplasia is accompanied by impaired oxidative status by increasing levels of MDA, depletion of GSH concentrations and a decrease in the activity of all the antioxidant enzymes studied. These results have allowed us to understand a part of the aetiology of benign prostate hyperplasia related to oxidative stress.

  2. Migraine with benign episodic unilateral mydriasis

    Directory of Open Access Journals (Sweden)

    Jabr FI

    2011-06-01

    Full Text Available Nedaa Skeik1, Fadi I Jabr21Mayo Clinic, Rochester, MN, USA; 2Horizon Medical Center, Hospital Medicine, Dickson, TN, USAAbstract: Pupil asymmetry or anisocoria can have benign or malignant causes, and be categorized as acute or chronic. It can also be a normal finding in about 20% of cases. Benign episodic unilateral mydriasis is an isolated benign cause of intermittent pupil asymmetry. The exact pathophysiology is not always understood. According to one hypothesis, it is due to discordance between the sympathetic and parasympathetic systems. It is occasionally seen in patients with migraine. Some authors consider it a limited form of ophthalmoplegic migraine. We report a case of benign episodic unilateral mydriasis diagnosed in a 30-year-old lady with a history of migraine who had extensive negative neurological evaluation.Keywords: anisocoria, migraine, unilateral episodic mydriasis

  3. Genetics Home Reference: benign familial neonatal seizures

    Science.gov (United States)

    ... Facebook Share on Twitter Your Guide to Understanding Genetic Conditions Search MENU Toggle navigation Home Page Search ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions BFNS benign familial neonatal seizures ...

  4. Benign Metastatic Leiomyoma Presenting as a Hemothorax

    Directory of Open Access Journals (Sweden)

    Anna M. Ponea

    2013-01-01

    Full Text Available Uterine leiomyomas have been reported to metastasize to various organs including the lungs, skeletal muscles, bone marrow, peritoneum, and heart. They may present with symptoms related to the metastases several years after hysterectomy. These tumors regress after menopause, and it is rare to detect active tumors in postmenopausal women. Despite their ability to metastasize, they are considered to be benign due to the lack of anaplasia. Pulmonary benign metastasizing leiomyoma is usually detected in the form of pulmonary nodules incidentally on imaging. Tissue biopsy of these nodules is required to identify them as benign metastasizing leiomyomas. Immunohistochemical analysis and molecular profiling may further help detect any malignant transformation in it. Untreated pulmonary benign metastasizing leiomyoma may result in the formation of cystic structures, destruction of lung parenchyma, and hemothorax and may cause respiratory failure. Surgical resection and hormonal therapy help prevent progression of this disease and provide an avenue for a cure.

  5. Benign metastatic leiomyoma presenting as a hemothorax.

    Science.gov (United States)

    Ponea, Anna M; Marak, Creticus P; Goraya, Harmeen; Guddati, Achuta K

    2013-01-01

    Uterine leiomyomas have been reported to metastasize to various organs including the lungs, skeletal muscles, bone marrow, peritoneum, and heart. They may present with symptoms related to the metastases several years after hysterectomy. These tumors regress after menopause, and it is rare to detect active tumors in postmenopausal women. Despite their ability to metastasize, they are considered to be benign due to the lack of anaplasia. Pulmonary benign metastasizing leiomyoma is usually detected in the form of pulmonary nodules incidentally on imaging. Tissue biopsy of these nodules is required to identify them as benign metastasizing leiomyomas. Immunohistochemical analysis and molecular profiling may further help detect any malignant transformation in it. Untreated pulmonary benign metastasizing leiomyoma may result in the formation of cystic structures, destruction of lung parenchyma, and hemothorax and may cause respiratory failure. Surgical resection and hormonal therapy help prevent progression of this disease and provide an avenue for a cure.

  6. Oromotor Dyspraxia in Benign Childhood Epilepsy

    OpenAIRE

    J Gordon Millichap

    1989-01-01

    A six year old right handed boy with prolonged intermittent drooling, oromotor dyspraxia, and benign childhood epilepsy with centrotemporal spikes is reported from the Departments of Pediatrics and Neurology, Centre Hospitalier, Universitaire Vaudois, Lausanne, Switzerland.

  7. Genetics Home Reference: benign recurrent intrahepatic cholestasis

    Science.gov (United States)

    ... All Close All Description Benign recurrent intrahepatic cholestasis (BRIC) is characterized by episodes of liver dysfunction called ... a lack of appetite. A common feature of BRIC is the reduced absorption of fat in the ...

  8. The Initiation and Propagation of Helium Detonations in White Dwarf Envelopes

    CERN Document Server

    Shen, Ken J

    2014-01-01

    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 ...

  9. Publicly Released Prompt Radiation Spectra Suitable for Nuclear Detonation Simulations

    Science.gov (United States)

    2017-03-01

    provides numerical data sets to support radiation transport modeling. 15. SUBJECT TERMS Radiation Transport Nuclear Detonation Initial Radiation Urban ...radiation transport model. These models include 3-D representation of urban geometries complete with internal structure and external walls. ARA...in a radiation transport model. The subsequent radiation transport model results are essential input for civilian emergency planning, consequence

  10. Detonation and combustion of explosives: A selected bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Dobratz, B. [comp.

    1998-08-01

    This bibliography consists of citations pertinent to the subjects of combustion and detonation of energetic materials, especially, but not exclusively, of secondary solid high explosives. These references were selected from abstracting sources, conference proceedings, reviews, and also individual works. The entries are arranged alphabetically by first author and numbered sequentially. A keyword index is appended.

  11. Experimental Investigation on Performance of Pulse Detonation Rocket Engine Model

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; FAN Wei; YAN Chuan-jun; HU Cheng-qi; YE Bin

    2007-01-01

    The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and purge gas. PDRE test model was 50 mm in inner diameter by 1.2 m long. The DDT (defiagration to detonation transition) enhancement device Shchelkin spiral was used in the test model.The effects of detonation frequency on its time-averaged thrust and specific impulse were experimentally investigated. The obtained results showes that the time-averaged thrust of PDRE test model was approximately proportional to the detonation frequency. For the detonation frequency 20 Hz, the time-averaged thrust was around 107 N, and the specific impulse was around 125 s. The nozzle experiments were conducted using PDRE test model with three traditional nozzles. The experimental results obtained demonstrated that all of those nozzles could augment the thrust and specific impulse. Among those three nozzles, the convergent nozzle had the largest increased augmentation, which was approximately 18%, under the specific condition of the experiment.

  12. A thermochemically derived global reaction mechanism for detonation application

    Science.gov (United States)

    Zhu, Y.; Yang, J.; Sun, M.

    2012-07-01

    A 4-species 4-step global reaction mechanism for detonation calculations is derived from detailed chemistry through thermochemical approach. Reaction species involved in the mechanism and their corresponding molecular weight and enthalpy data are derived from the real equilibrium properties. By substituting these global species into the results of constant volume explosion and examining the evolution process of these global species under varied conditions, reaction paths and corresponding rates are summarized and formulated. The proposed mechanism is first validated to the original chemistry through calculations of the CJ detonation wave, adiabatic constant volume explosion, and the steady reaction structure after a strong shock wave. Good agreement in both reaction scales and averaged thermodynamic properties has been achieved. Two sets of reaction rates based on different detailed chemistry are then examined and applied for numerical simulations of two-dimensional cellular detonations. Preliminary results and a brief comparison between the two mechanisms are presented. The proposed global mechanism is found to be economic in computation and also competent in description of the overall characteristics of detonation wave. Though only stoichiometric acetylene-oxygen mixture is investigated in this study, the method to derive such a global reaction mechanism possesses a certain generality for premixed reactions of most lean hydrocarbon mixtures.

  13. Wave dynamic processes in cellular detonation reflection from wedges

    Institute of Scientific and Technical Information of China (English)

    Zongmin Hu; Zonglin Jiang

    2007-01-01

    When the cell width of the incident deto-nation wave (IDW) is comparable to or larger than theMach stem height,self-similarity will fail during IDWreflection from a wedge surface.In this paper,the det-onation reflection from wedges is investigated for thewave dynamic processes occurring in the wave front,including transverse shock motion and detonation cellvariations behind the Mach stem.A detailed reactionmodel is implemented to simulate two-dimensional cel-lular detonations in stoichiometric mixtures of H2/O2diluted by Argon.The numerical results show that thetransverse waves,which cross the triple point trajec-tory of Mach reflection,travel along the Mach stem andreflect back from the wedge surface,control the size ofthe cells in the region swept by the Mach stem.It is theenergy carried by these transverse waves that sustainsthe triple-wave-collision with a higher frequency withinthe over-driven Mach stem.In some cases,local wavedynamic processes and wave structures play a dominantrole in determining the pattern of cellular record,lead-ing to the fact that the cellular patterns after the Machstem exhibit some peculiar modes.

  14. The Nuclear Detonation Detection System on the GPS satellites

    Energy Technology Data Exchange (ETDEWEB)

    Higbie, P.R. [Los Alamos National Lab., NM (United States); Blocker, N.K. [Sandia National Labs., Albuquerque, NM (United States)

    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.

  15. Indirect detonation initiation using acoustic timescale thermal power deposition

    CERN Document Server

    Regele, Jonathan D; Vezolainen, Alexei; Vasilyev, Oleg V

    2012-01-01

    A fluid dynamics video is presented that demonstrates an indirect detonation initiation process. In this process, a transient power deposition adds heat to a spatially resolved volume of fluid in an amount of time that is similar to the acoustic timescale of the fluid volume. A highly resolved two-dimensional simulation shows the events that unfold after the heat is added.

  16. Detonation of CHO working substances in a laser jet engine

    Science.gov (United States)

    Ageichik, A. A.; Repina, E. V.; Rezunkov, Yu. A.; Safronov, A. L.

    2009-03-01

    Laser-induced ablation of materials (including polymers and a variety of polycrystalline substances with a CHO chemical composition) is studied theoretically and experimentally. Based on experimental data, a parametric physicochemical model of detonation of these materials is put forward with the aim to estimate the efficiency of laser thrust formation in jet engines.

  17. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Reaugh, J E

    2011-11-22

    HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the response of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable

  18. Using embedded fibers to measure explosive detonation velocities

    Energy Technology Data Exchange (ETDEWEB)

    Podsednik, Jason W.; Parks, Shawn Michael; Navarro, Rudolfo J.

    2012-07-01

    Single-mode fibers were cleverly embedded into fixtures holding nitromethane, and used in conjunction with a photonic Doppler velocimeter (PDV) to measure the associated detonation velocity. These measurements have aided us in our understanding of energetic materials and enhanced our diagnostic capabilities.

  19. NOx Emissions from a Rotating Detonation-wave Engine

    Science.gov (United States)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2016-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. Results to date show that NOx emissions are not a problem for the RDE due to the short residence times and the nature of the flow field. Furthermore, simulations show that the amount of NOx can be further reduced by tailoring the fluid dynamics within the RDE.

  20. Detonation equation of state at LLNL, 1995. Revision 3

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P.C.; Wu, B.; Haselman, L.C. Jr.

    1996-02-01

    JWL`s and 1-D Look-up tables are shown to work for ``one-track`` experiments like cylinder shots and the expanding sphere. They fail for ``many-track`` experiments like the compressed sphere. As long as the one-track experiment has dimensions larger than the explosive`s reaction zone and the explosive is near-ideal, a general JWL with R{sub 1} = 4.5 and R{sub 2} = 1.5 can be constructed, with both {omega} and E{sub o} being calculated from thermochemical codes. These general JWL`s allow comparison between various explosives plus recalculation of the JWL for different densities. The Bigplate experiment complements the cylinder test by providing continuous oblique angles of shock incidence from 0{degrees} to 70{degrees}. Explosive reaction zone lengths are determined from metal plate thicknesses, extrapolated run-to-detonation distances, radius size effects and detonation front curvature. Simple theories of the cylinder test, Bigplate, the cylinder size effect and detonation front curvature are given. The detonation front lag at the cylinder edge is shown to be proportional to the half-power of the reaction zone length. By calibrating for wall blow-out, a full set of reaction zone lengths from PETN to ANFO are obtained. The 1800--2100 K freezing effect is shown to be caused by rapid cooling of the product gases. Compiled comparative data for about 80 explosives is listed. Ten Chapters plus an Appendix.

  1. Oral benign fibrous histiocytoma: two case reports

    OpenAIRE

    Menditti, Dardo; Laino, Luigi; Mezzogiorno, Antonio; Sava, Sara; Bianchi, Alexander; Caruso, Giovanni; Di Maio, Luigi; Baldi, Alfonso

    2009-01-01

    Fibrous histiocytoma is a benign soft tissue tumour arising as a fibrous mass everywhere in the human body. The involvement of the oral cavity is rare. We report two cases of benign fibrous histiocytoma that localized in the oral cavity. The clinical and histological features of the lesion are reported. Finally, a literature revision of this pathology at the level of the oral cavity is reported.

  2. Benign nontraumatic osteolytic vertebral collapse simulating malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Sattari, Azadeh [Hopital Lariboisiere, Department of Musculoskeletal Radiology, Paris Cedex 10 (France); Quillard, Alain [Hopital Lariboisiere, Department of Pathology, Paris Cedex 10 (France); Laredo, Jean-Denis [Hopital Lariboisiere, Department of Musculoskeletal Radiology, Paris Cedex 10 (France); University of Pennsylvania Health System, Department of Radiology, Philadelphia, PA (United States)

    2008-03-15

    This study described the imaging features of a distinctive pattern of biopsy-proven benign non-traumatic vertebral collapse (VC) that can mimic malignancy. Among 240 patients referred with painful VC over a 10-year period, we retrospectively selected 15 cases of benign VC which simulated malignancy, due to cortical bone destruction on radiographs. The diagnosis of benign origin was documented by percutaneous biopsy and 12-months of follow-up. Radiographs, CT and MR images of the spine were reviewed. Findings suggestive of malignancy included destruction involving the anterolateral cortex, posterior cortex and pedicles of the vertebral body (46%,15% and 15% respectively) at CT, epidural soft-tissue masses on CT (23%) and MR images (21%), and diffuse low signal-intensity (SI) of the vertebral body (50%) and pedicles (79%) on T1-weighted images. Features suggestive of a benign origin included an intravertebral vacuum phenomenon on radiographs and CT (13%), fracture lines within the vertebral body (92%) or pedicles (62%) at CT and presence an intravertebral area of high SI on T2-weighted images (93%). Benign non-traumatic osteolytic VC can simulate malignancy on radiographs. The features, above mentioned on CT and MR suggestive of a benign VC, are useful in interpreting biopsy results of such lesions and avoiding unnecessary repeat biopsy. (orig.)

  3. The combustion-deflagration-detonation transition: experimental study and modeling; Transition combustion-deflagration-detonation: etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Lemoine, D.; Belmas, R. [CEA Le Ripault, 37 - Tours (France)

    1996-12-31

    The results of specific thermal tests performed on a pressed octogene-based explosive compound allow to identify the physical mechanisms which govern the combustion-deflagration-detonation transition process in this compound. A simple and efficient modeling of these phenomena is proposed. (J.S.)

  4. Development of a Gas-Fed Pulse Detonation Research Engine

    Science.gov (United States)

    Litchford, Ron J.; Hutt, John (Technical Monitor)

    2001-01-01

    In response to the growing need for empirical data on pulse detonation engine performance and operation, NASA Marshall Space Flight Center has developed and placed into operation a low-cost gas-fed pulse detonation research engine. The guiding design strategy was to achieve a simple and flexible research apparatus, which was inexpensive to build and operate. As such, the engine was designed to operate as a heat sink device, and testing was limited to burst-mode operation with run durations of a few seconds. Wherever possible, maximum use was made of standard off-the-shelf industrial or automotive components. The 5-cm diameter primary tube is about 90-cm long and has been outfitted with a multitude of sensor and optical ports. The primary tube is fed by a coaxial injector through an initiator tube, which is inserted directly into the injector head face. Four auxiliary coaxial injectors are also integrated into the injector head assembly. All propellant flow is controlled with industrial solenoid valves. An automotive electronic ignition system was adapted for use, and spark plugs are mounted in both tubes so that a variety of ignition schemes can be examined. A microprocessor-based fiber-optic engine control system was developed to provide precise control over valve and ignition timing. Initial shakedown testing with hydrogen/oxygen mixtures verified the need for Schelkin spirals in both the initiator and primary tubes to ensure rapid development of the detonation wave. Measured pressure wave time-of-flight indicated detonation velocities of 2.4 km/sec and 2.2 km/sec in the initiator and primary tubes, respectively. These values implied a fuel-lean mixture corresponding to an H2 volume fraction near 0.5. The axial distribution for the detonation velocity was found to be essentially constant along the primary tube. Time-resolved thrust profiles were also acquired for both underfilled and overfilled tube conditions. These profiles are consistent with previous time

  5. Benign multicystic peritoneal mesothelioma: a case report

    Directory of Open Access Journals (Sweden)

    Papapaulou Leonidas

    2010-11-01

    Full Text Available Abstract Introduction We report the case of a patient with a benign multicystic peritoneal mesothelioma and describe its appearance on computed tomography scans and ultrasonography, in correlation with gross clinical and pathological findings. Case presentation A 72-year-old Caucasian woman presented to our emergency department with acute abdomen signs and symptoms. A clinical examination revealed a painful palpable mass in her left abdomen. Abdominal ultrasonography and computed tomography demonstrated the presence of a large cystic mass in her left upper abdomen, adjacent to her left hemidiaphragm. The lower border of the mass extended to the upper margin of her pelvis. A complete resection of the lesion was performed. Pathological analysis showed a benign multicystic peritoneal mesothelioma. Conclusions Benign multicystic peritoneal mesothelioma is a rare lesion with a non-specific appearance on imaging. Its diagnosis always requires pathological analysis.

  6. Far Field Modeling Methods For Characterizing Surface Detonations

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    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.

  7. Study of a Model Equation in Detonation Theory

    KAUST Repository

    Faria, Luiz

    2014-04-24

    Here we analyze properties of an equation that we previously proposed to model the dynamics of unstable detonation waves [A. R. Kasimov, L. M. Faria, and R. R. Rosales, Model for shock wave chaos, Phys. Rev. Lett., 110 (2013), 104104]. The equation is ut+ 1/2 (u2-uu (0-, t))x=f (x, u (0-, t)), x > 0, t < 0. It describes a detonation shock at x = 0 with the reaction zone in x > 0. We investigate the nature of the steady-state solutions of this nonlocal hyperbolic balance law, the linear stability of these solutions, and the nonlinear dynamics. We establish the existence of instability followed by a cascade of period-doubling bifurcations leading to chaos. © 2014 Society for Industrial and Applied Mathematics.

  8. Detonation initiation developing from the Richtmyer-Meshkov instability

    Institute of Scientific and Technical Information of China (English)

    H.H.Teng; Z.L.Jiang; Z.M.Hu

    2007-01-01

    Detonation initiation resulting from theRichtmyer-Meshkov instability is investigated numericallyin the configuration of the shock/spark-induced-deflagrationinteraction in a combustive gas mixture. Two-dimensionalmulti-species Navier-Stokes equations implemented with thedetailed chemical reaction model are solved with thedispersion-controlled dissipative scheme. Numerical resultsshow that the spark can create a blast wave and ignite defla-grations. Then, the deflagration waves are enhanced due tothe Richtmyer-Meshkov instability, which provides detona-tion initiations with local environment conditions. Byexamining the deflagration fronts, two kinds of the initiationmechanisms are identified. One is referred to as the deflagra-tion front acceleration with the help of the weak shock wave,occurring on the convex surfaces, and the other is the hotspot explosion deriving from the deflagration front focusing,occurring on the concave surfaces.

  9. Set-valued solutions for non-ideal detonation

    KAUST Repository

    Semenko, Roman

    2015-12-11

    The existence and structure of a steady-state gaseous detonation propagating in a packed bed of solid inert particles are analyzed in the one-dimensional approximation by taking into consideration frictional and heat losses between the gas and the particles. A new formulation of the governing equations is introduced that eliminates the difficulties with numerical integration across the sonic singularity in the reactive Euler equations. With the new algorithm, we find that when the sonic point disappears from the flow, there exists a one-parameter family of solutions parameterized by either pressure or temperature at the end of the reaction zone. These solutions (termed “set-valued” here) correspond to a continuous spectrum of the eigenvalue problem that determines the detonation velocity as a function of a loss factor.

  10. Study of a model equation in detonation theory: multidimensional effects

    CERN Document Server

    Faria, Luiz M; Rosales, Rodolfo R

    2015-01-01

    We extend the reactive Burgers equation presented in Kasimov et al. Phys. Rev. Lett., 110 (2013) and Faria et al. SIAM J. Appl. Maths, 74 (2014), to include multidimensional effects. Furthermore, we explain how the model can be rationally justified following the ideas of the asymptotic theory developed in Faria et al. JFM (2015). The proposed model is a forced version of the unsteady small disturbance transonic flow equations. We show that for physically reasonable choices of forcing functions, traveling wave solutions akin to detonation waves exist. It is demonstrated that multidimensional effects play an important role in the stability and dynamics of the traveling waves. Numerical simulations indicate that solutions of the model tend to form multi-dimensional patterns analogous to cells in gaseous detonations.

  11. CIRCUMSTELLAR ABSORPTION IN DOUBLE DETONATION TYPE Ia SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ken J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Guillochon, James [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Foley, Ryan J., E-mail: kenshen@astro.berkeley.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-06-20

    Upon formation, degenerate He core white dwarfs are surrounded by a radiative H-rich layer primarily supported by ideal gas pressure. In this Letter, we examine the effect of this H-rich layer on mass transfer in He+C/O double white dwarf binaries that will eventually merge and possibly yield a Type Ia supernova (SN Ia) in the double detonation scenario. Because its thermal profile and equation of state differ from the underlying He core, the H-rich layer is transferred stably onto the C/O white dwarf prior to the He core's tidal disruption. We find that this material is ejected from the binary system and sweeps up the surrounding interstellar medium hundreds to thousands of years before the SN Ia. The close match between the resulting circumstellar medium profiles and values inferred from recent observations of circumstellar absorption in SNe Ia gives further credence to the resurgent double detonation scenario.

  12. Performance Impact of Deflagration to Detonation Transition Enhancing Obstacles

    Science.gov (United States)

    Paxson, Daniel E.; Schauer, Frederick; Hopper, David

    2012-01-01

    A sub-model is developed to account for the drag and heat transfer enhancement resulting from deflagration-to-detonation (DDT) inducing obstacles commonly used in pulse detonation engines (PDE). The sub-model is incorporated as a source term in a time-accurate, quasi-onedimensional, CFD-based PDE simulation. The simulation and sub-model are then validated through comparison with a particular experiment in which limited DDT obstacle parameters were varied. The simulation is then used to examine the relative contributions from drag and heat transfer to the reduced thrust which is observed. It is found that heat transfer is far more significant than aerodynamic drag in this particular experiment.

  13. Engineering models of deflagration-to-detonation transition

    Energy Technology Data Exchange (ETDEWEB)

    Bdzil, J.B.; Son, S.F.

    1995-07-01

    For the past two years, Los Alamos has supported research into the deflagration-to-detonation transition (DDT) in damaged energetic materials as part of the explosives safety program. This program supported both a theory/modeling group and an experimentation group. The goal of the theory/modeling group was to examine the various modeling structures (one-phase models, two-phase models, etc.) and select from these a structure suitable to model accidental initiation of detonation in damaged explosives. The experimental data on low-velocity piston supported DDT in granular explosive was to serve as a test bed to help in the selection process. Three theoretical models have been examined in the course of this study: (1) the Baer-Nunziato (BN) model, (2) the Stewart-Prasad-Asay (SPA) model and (3) the Bdzil-Kapila-Stewart model. Here we describe these models, discuss their properties, and compare their features.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. BENIGN BREAST DISEASE: OUR INSTITUTIONAL EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Harish Kumar

    2014-11-01

    Full Text Available BACKGROUND AND OBJECTIVES: In this modern era of change in dietary habits, life style and increased awareness about the self-breast examination, the rate of detection of breast lump is on increasing trend. Due to its enormous anatomical and physiological changes during different phases of life, breast diseases are not uncommon. The benign conditions however are also associated with morbidity and are of great concern to the patient. This study was carried out to compare the age distribution and proportion of various benign breast tumors, taking into account the various factors associated with them. A correlation of clinical and histopathological diagnosis was drawn and thus the specificity of clinical diagnosis. METHODS: Prospective review of 50 patients from General Surgery department, who are found to have benign breast tumors on clinico-pathological examination, Bowring and Lady Curzon Hospitals, attached to Bangalore Medical College & Research Institute, Bangalore selected during the period from October 2011 to April 2014 on random basis. Post-operative follow up done to note the complications both in hospital and after discharge. RESULTS: Patients predominantly presented with lump in breast were fibroadenoma and fibrocystic disease. Ductal papilloma, phyllodes tumor and lipoma were also encountered. All patients underwent FNAC. Treatment was mostly surgical in the form of excision, simple mastectomy, microdochotomy and wide local excision. All the specimens were subjected to histopathological examination. Using clinical diagnosis, FNAC and histopathology increased the accuracy of diagnosis. Cases followed up and no recurrence was found. CONCLUSIONS: Commonest benign breast tumor found was Fibroadenoma (78%. Majority of the patients were in the active reproductive age group. Fibroadenoma was more common in 2nd decade of life, whereas fibrocystic disease found in 3rd decade. Majority of benign breast lesions presented with painless lump. FNAC

  16. Effect of chemical reactivity on the detonation initiation in shock accelerated flow in a confined space

    Institute of Scientific and Technical Information of China (English)

    Yue-Jin Zhu; Gang Dong; Yi-Xin Liu; Bao-Chun Fan; Hua Jiang

    2013-01-01

    The interactions of a spherical flame with an incident shock wave and its reflected shock wave in a confined space were investigated using the three-dimensional reactive Navier-Stokes equations,with emphasis placed on the effect of chemical reactivity of mixture on the flame distortion and detonation initiation after the passage of the reflected shock wave.It is shown that the spatio-temporal characteristics of detonation initiation depend highly on the chemical reactivity of the mixture.When the chemical reactivity enhances,the flame can be severely distorted to form a reactive shock bifurcation structure with detonations initiating at different three-dimensional spatial locations.Moreover,the detonation initiation would occur earlier in a mixture of more enhanced reactivity.The results reveal that the detonations arise from hot spots in the unburned region which are initiated by the shock-detonation-transition mechanism.

  17. Multi-Dimensional Double Detonation of Sub-Chandrasekhar Mass White Dwarfs

    CERN Document Server

    Moll, Rainer

    2013-01-01

    Using 2D and 3D simulation, we study the "robustness" of the double detonation scenario for Type Ia supernovae, in which a detonation in the helium shell of a carbon-oxygen white dwarf induces a secondary detonation in the underlying core. We find that a helium detonation cannot easily descend into the core unless it commences (artificially) well above the hottest layer calculated for the helium shell in current presupernova models. Compressional waves induced by the sliding helium detonation, however, robustly generate hot spots which trigger a detonation in the core. Our simulations show that this is true even for non-axisymmetric initial conditions. If the helium is ignited at multiple points, the internal waves can pass through one another or be reflected, but this added complexity does not defeat the generation of the hot spot. The ignition of very low-mass helium shells depends on whether a thermonuclear runaway can simultaneously commence in a sufficiently large region.

  18. Multi-frame visualization for detonation wave diffraction

    Science.gov (United States)

    Nagura, Y.; Kasahara, J.; Matsuo, A.

    2016-09-01

    When a detonation wave emerges from a tube into unconfined space filled with a gas mixture, detonation wave diffraction occurs due to abrupt changes in the cross-sectional area. In the present study, we focused on the local explosion in reinitiation and propagation of a transverse detonation wave by performing comprehensive and direct observation with high time resolution visualization in a two-dimensional rectangular channel. Using the visualization methods of shadowgraph and multi-frame, short-time, open-shutter photography, we determined where the wall reflection point is generated, and also determined where the bright point is originated by the local explosion, and investigated the effects of the deviation angle and initial pressure of the gas mixture. We found that the reinitiation of detonation had two modes that were determined by the deviation angle of the channel. If the deviation angle was less than or equal to 30°, the local explosion of reinitiation might occur in the vicinity of the channel wall, and if the deviation angle was greater than or equal to 60°, the local explosion might originate on the upper side of the tube exit. With a deviation angle greater than 60°, the position of the wall reflection point depended on the cell width, so the radial distance of the wall reflection point from the apex of the tube exit was about 12 times the cell width. Similarly, the bright point (local explosion point) was located a distance of about 11 times the cell width from the apex of the tube exit, with a circumferential angle of 48°.

  19. Set-valued solutions for non-ideal detonation

    OpenAIRE

    Semenko, Roman; Faria, Luiz; Kasimov, Aslan; Ermolaev, Boris

    2013-01-01

    The existence and structure of steady gaseous detonation propagating in a packed bed of solid inert particles are analyzed in the one-dimensional approximation by taking into consideration frictional and heat losses between the gas and the particles. A new formulation of the governing equations is introduced that eliminates the well-known difficulties with numerical integration across the sonic singularity in the reactive Euler equations. The new algorithm allows us to determine that the deto...

  20. Radiofrequency ablation for benign thyroid nodules.

    Science.gov (United States)

    Bernardi, S; Stacul, F; Zecchin, M; Dobrinja, C; Zanconati, F; Fabris, B

    2016-09-01

    Benign thyroid nodules are an extremely common occurrence. Radiofrequency ablation (RFA) is gaining ground as an effective technique for their treatment, in case they become symptomatic. Here we review what are the current indications to RFA, its outcomes in terms of efficacy, tolerability, and cost, and also how it compares to the other conventional and experimental treatment modalities for benign thyroid nodules. Moreover, we will also address the issue of treating with this technique patients with cardiac pacemakers (PM) or implantable cardioverter-defibrillators (ICD), as it is a rather frequent occurrence that has never been addressed in detail in the literature.

  1. The decline of hysterectomy for benign disease.

    LENUS (Irish Health Repository)

    Horgan, R P

    2012-01-31

    Hysterectomy is one of the most common gynaecological surgical procedures performed but there appears to be a decline in the performance of this procedure in Ireland in recent times. We set out to establish the extent of the decline of hysterectomy and to explore possible explanations. Data for hysterectomy for benign disease from Ireland was obtained from the Hospital In-Patient Enquiry Scheme (HIPE) section of the Economic and Social Research Institute for the years 1999 to 2006. The total number of hysterectomies performed for benign disease showed a consistent decline during this time. There was a 36% reduction in the number of abdominal hysterectomy procedures performed.

  2. Benign cephalic histiocytosis: report of four cases.

    Science.gov (United States)

    de Luna, M L; Glikin, I; Golberg, J; Stringa, S; Schroh, R; Casas, J

    1989-09-01

    We cared for four patients with benign cephalic histiocytosis, a self-healing non-X, nonlipid cutaneous histiocytosis of children. The age of onset of the disease was 5 to 9 months, with papules and erythematous macules involving the head (mainly the cheeks), and posterior spread to the trunk and limbs in three patients. Microscopic examination of skin biopsies revealed a histiocytic infiltrate in the superficial dermis that was S100 protein-negative by immunoperoxidase (PAP method). One patient showed comma-shaped bodies and desmosomelike junctions on electron microscopy. No Birbeck's granules were present. Benign cephalic histiocytosis is a self-limiting condition that requires no treatment.

  3. Projected Response of Typical Detonators to Electrostatic Discharge (ESD) Environments

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M J

    2002-12-20

    The purpose of this discussion is to indicate the threshold values for low-order detonator response by using first principles applied to pin-to-pin configurations and associated limits in pin-to-case scenarios. In addition an attempt to define the electrical environment by first principles is shown to be inadequate and indicates the need to define the electrical insult by reasonable standards. A comparison of two accepted electrical models and a combination of the extreme reported levels from both standards are used to establish an extreme set of parameters for a safety assessment. A simplification of the critical electrical insult parameters is then shown and demonstrated to provide the initial screening protocol with easily defined electrical dimensions of action integral. Action integral and the conductive material properties are the basic parameters needed to define the solid, liquid, and gas phases of the material used for detonator bridge wires. The resulting material phases are directly related to detonator response thresholds. The discussion concludes by showing the ability of ESD insults to arc from pin-to-case, the limited knowledge of the associated arc initiation process, and the modeling need for a reasonable arc resistance in pin-to-case scenarios.

  4. A Kinetic Approach to Propagation and Stability of Detonation Waves

    Science.gov (United States)

    Monaco, R.; Bianchi, M. Pandolfi; Soares, A. J.

    2008-12-01

    The problem of the steady propagation and linear stability of a detonation wave is formulated in the kinetic frame for a quaternary gas mixture in which a reversible bimolecular reaction takes place. The reactive Euler equations and related Rankine-Hugoniot conditions are deduced from the mesoscopic description of the process. The steady propagation problem is solved for a Zeldovich, von Neuman and Doering (ZND) wave, providing the detonation profiles and the wave thickness for different overdrive degrees. The one-dimensional stability of such detonation wave is then studied in terms of an initial value problem coupled with an acoustic radiation condition at the equilibrium final state. The stability equations and their initial data are deduced from the linearized reactive Euler equations and related Rankine-Hugoniot conditions through a normal mode analysis referred to the complex disturbances of the steady state variables. Some numerical simulations for an elementary reaction of the hydrogen-oxygen chain are proposed in order to describe the time and space evolution of the instabilities induced by the shock front perturbation.

  5. Shock and Detonation Physics at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, David L [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve A [Los Alamos National Laboratory

    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. Energy Loss in Pulse Detonation Engine due to Fuel Viscosity

    Directory of Open Access Journals (Sweden)

    Weipeng Hu

    2014-01-01

    Full Text Available Fluid viscosity is a significant factor resulting in the energy loss in most fluid dynamical systems. To analyze the energy loss in the pulse detonation engine (PDE due to the viscosity of the fuel, the energy loss in the Burgers model excited by periodic impulses is investigated based on the generalized multisymplectic method in this paper. Firstly, the single detonation energy is simplified as an impulse; thus the complex detonation process is simplified. And then, the symmetry of the Burgers model excited by periodic impulses is studied in the generalized multisymplectic framework and the energy loss expression is obtained. Finally, the energy loss in the Burgers model is investigated numerically. The results in this paper can be used to explain the difference between the theoretical performance and the experimental performance of the PDE partly. In addition, the analytical approach of this paper can be extended to the analysis of the energy loss in other fluid dynamic systems due to the fluid viscosity.

  7. Schlieren Imaging and Pulsed Detonation Engine Testing of Ignition by a Nanosecond Repetitively Pulsed Discharge

    Science.gov (United States)

    2016-05-16

    generation and facilitate the deflagration-to-detonation transition ( DDT ), the length of which was 91.4 cm for ethylene experiments and 121.9 cm for...flame and undergo DDT . Third is detonation wave propagation, which produces a rapid pressure rise, accelerating the burned gas through the detonation...value, the wave speed is determined to be the C–J velocity. To determine the DDT distance, the wave speed is linearly interpolated between the mea

  8. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES...protection in the United States. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR...DISTRIBUTION UNLIMITED. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES

  9. On the propagation mechanism of a detonation wave in a round tube with orifice plates

    Science.gov (United States)

    Ciccarelli, G.; Cross, M.

    2016-09-01

    This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

  10. Volumetric initiation of gaseous detonation by radiant heating of suspended microparticles

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    2016-02-01

    The concept of detonation wave initiation in the local volume of a fuel-gas mixture containing suspended chemically neutral microparticles heated by radiant energy from an external source is proposed. Mechanisms of initiation of the combustion and detonation waves in a region of accumulation of the radiation- heated microparticles have been studied by numerical simulation methods. Criteria that determine geometric dimensions of a region of the two-phase medium, which are necessary for the initiation of detonation waves, are formulated.

  11. Cavity Ignition in Supersonic Flow by Spark Discharge and Pulse Detonation

    Science.gov (United States)

    2014-08-18

    constant volume, through a detonation , or some combination. While a deflagration (flame) through constant volume combustion can provide rapid heat release...significantly disrupted, and the detonation was able to ignite and burn most of the fuel within the cavity. This led to decreased heat release in regime IV...locate/proci of the Combustion InstituteCavity ignition in supersonic flow by spark discharge and pulse detonation Timothy M. Ombrello a,⇑, Campbell D

  12. Direct initiation of gaseous detonation via radiative heating of microparticles volumetrically suspended in the gas

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    2015-11-01

    We propose a new conceptual approach for direct detonation initiation in the gaseous mixtures seeded with micro particles via the radiative heating from the external energy source. The basic mechanisms of energy absorption, ignition and detonation formation are analyzed numerically on the example of hydrogen-oxygen mixture. Obtained data is very promising and allows us to formulate conditions for the source power to ignite detonation in certain system geometry.

  13. Classification of Battlespace Detonations from Temporally Resolved Multi-Band Imagery and Mid-Infrared Spectra

    Science.gov (United States)

    2005-03-01

    called the heat of detonation and includes only the combustion of the explosive reactants, not the heat associated with the secondary afterburn. This...32:24] 2. Basic Phenomenology As mentioned earlier, the heat of detonation ∆H is the heat (or energy) generated during the reaction and is...232, −++++= eTdTcTbTaTC ip , (5) where the coefficients a through e are defined in Table 2, the heat of detonation becomes an integral

  14. The role of multidimensional instabilities in direct initiation of gaseous detonations in free space

    KAUST Repository

    Shen, Hua

    2017-01-20

    We numerically investigate the direct initiation of detonations driven by the propagation of a blast wave into a unconfined gaseous combustible mixture to study the role played by multidimensional instabilities in direct initiation of stable and unstable detonations. To this end, we first model the dynamics of unsteady propagation of detonation using the one-dimensional compressible Euler equations with a one-step chemical reaction model and cylindrical geometrical source terms. Subsequently, we use two-dimensional compressible Euler equations with just the chemical reaction source term to directly model cylindrical detonations. The one-dimensional results suggest that there are three regimes in the direct initiation for stable detonations, that the critical energy for mildly unstable detonations is not unique, and that highly unstable detonations are not self-sustainable. These phenomena agree well with one-dimensional theories and computations available in the literature. However, our two-dimensional results indicate that one-dimensional approaches are valid only for stable detonations. In mildly and highly unstable detonations, one-dimensional approaches break down because they cannot take the effects and interactions of multidimensional instabilities into account. In fact, instabilities generated in multidimensional settings yield the formation of strong transverse waves that, on one hand, increase the risk of failure of the detonation and, on the other hand, lead to the initiation of local over-driven detonations that enhance the overall self-sustainability of the global process. The competition between these two possible outcomes plays an important role in the direct initiation of detonations.

  15. Instability Criterion of One-Dimensional Detonation Wave with Three-Step Chain Branching Reaction Model

    Institute of Scientific and Technical Information of China (English)

    TENG Hong-Hui; JIANG Zong-Lin

    2011-01-01

    @@ One-dimensional detonation waves are simulated with the three-step chain branching reaction model, and the instability criterion is studied.The ratio of the induction zone length and the reaction zone length may be used to decide the instability, and the detonation becomes unstable with the high ratio.However, the ratio is not invariable with different heat release values.The critical ratio, corresponding to the transition from the stable detonation to the unstable detonation, has a negative correlation with the heat release.An empirical relation of the Chapman-Jouguet Mach number and the length ratio is proposed as the instability criterion.

  16. Effect of Void Size on the Detonation Pressure of Emulsion Explosives

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2002-07-01

    To study the effect of void size, detonation pressure as well as detonation velocity was measured using PVDF pressure gauge for the emulsion explosives sensitized with plastic balloons of five different size ranging from 0.05mm to 2.42mm. The experimental results were compared with the detonation pressure and velocity calculated using KHT code. The experimental results showed that the detonation pressure and velocity were strongly affected by void size, and that the fraction of ammonium nitrate reacted in the reaction zone was strongly dependent on void size.

  17. Application of a Schlieren diagnostic to the behavior of exploding bridge wire and laser detonators

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Michael J [Los Alamos National Laboratory; Clarke, Steven A [Los Alamos National Laboratory; Munger, Alan C [Los Alamos National Laboratory; Thomas, Keith A [Los Alamos National Laboratory

    2009-01-01

    Even though the exploding bridge wire (EBW) detonator has been in use for over 60 years, there are still discussions about the mechanism for achieving detonation. Los Alamos has been developing a high-power laser detonator to function in a manner similar to an EBW. Schlieren imaging techniques are applied to laser-driven detonator output in polydimethylsiloxane (POMS) samples to investigate the time-dependent geometry of the shock wave and to obtain instantaneous measurements of shock-front velocity. Velocity Hugoniot data are used to convert measured shock velocities to corresponding particle velocities, allowing instantaneous shock pressures to be obtained via Rankine-Hugoniot relations across the shock.

  18. Role of inlet reactant mixedness on the thermodynamic performance of a rotating detonation engine

    Science.gov (United States)

    Nordeen, C. A.; Schwer, D.; Schauer, F.; Hoke, J.; Barber, T.; Cetegen, B. M.

    2016-07-01

    Rotating detonation engines have the potential to achieve the high propulsive efficiencies of detonation cycles in a simple and effective annular geometry. A two-dimensional Euler simulation is modified to include mixing factors to simulate the imperfect mixing of injected reactant streams. Contrary to expectations, mixing is shown to have a minimal impact on performance. Oblique detonation waves are shown to increase local stream thermal efficiency, which compensates for other losses in the flow stream. The degree of reactant mixing is, however, a factor in controlling the stability and existence of rotating detonations.

  19. A two dimensional theory for two phase detonation of liquid films.

    Science.gov (United States)

    Rao, C. S. R.; Sichel, M.; Nicholls, J. A.

    1972-01-01

    A theory for the propagation of detonations through tubes coated with a thin fuel film is developed. Vaporization is assumed as the rate limiting process dominating the detonation structure. Inclusion of the boundary layer displacement effect resulted in better agreement between computed and measured propagation speed, pressure ratio, and reaction zone length than was obtained in an earlier theory in which this effect was neglected. New film detonation data is presented covering a wide range of fuel air ratios. A general Chapman-Jouguet condition is formulated for film detonations, and use of the plane of complete film vaporization as the Chapman-Jouguet plane is justified in the case of thin films.

  20. Shock-to-detonation transition in solid heterogeneous explosives; La transition choc-detonation dans les explosifs solides heterogenes

    Energy Technology Data Exchange (ETDEWEB)

    Belmas, R.

    2003-07-01

    This paper is an overview of the studies performed during the last decades on the shock-to-detonation transition process in heterogeneous explosives. We present the experimental and theoretical approaches mentioned in the literature and/or developed at CEA/DAM. The aim is to identify which main mechanisms govern this transition process and to evaluate the relevance of the available modeling tools. (author)

  1. Shock Wave Dynamics of Novel Aluminized Detonations and Empirical Model for Temperature Evolution from Post-Detonation Combustion Fireballs

    Science.gov (United States)

    2011-03-01

    to steel confinement, the presence of aluminum and wax in the HE as well as the presence of the 62   aluminized PE annulus surrounding the HE may...an aluminized plastic-bonded spin-cast liner all inside a steel munitions tube. The rate of change of temperature in the post- detonation combustion...0.18 m) inner diameter. The steel tubes are lined with an aluminized polyethylene (PE) annulus in the inner diameter and filled with melt-cast RDX

  2. A comparative audit of gunshot wounds and stab wounds to the neck in a South African metropolitan trauma service

    Science.gov (United States)

    Madsen, AS; Laing, GL; Bruce, JL

    2016-01-01

    Introduction The aim of this comparative study of gunshot wounds (GSWs) and stab wounds (SWs) to the neck was to quantify the impact of the mechanism of injury on the outcome and management of penetrating neck injury (PNI). Methods A prospective trauma registry was interrogated retrospectively. Data were analysed pertaining to demographics and injury severity score (ISS), physiology on presentation, anatomical site of wounds and injuries sustained, investigations, management, outcome and complications. Results There were 452 SW and 58 GSW cases over the 46 months of the study. Patients with GSWs were more likely to have extracervical injuries than those with SWs (69% vs 63%). The incidence of a ‘significant cervical injury’ was almost twice as high in the GSW cohort (55% vs 31%). For patients with transcervical GSWs, this increased to 80%. The mean ISS was 17 for GSW and 11 for SW patients. Those in the GSW cohort presented with threatened airways and a requirement for an emergency airway three times as often as patients with SWs (24% vs 7% and 14% vs 5% respectively). The incidence among GSW and SW patients respectively was 5% and 6% for airway injuries, 12% and 8% for injuries to the digestive tract, 21% and 16% for vascular injuries, 59% and 10% for associated cervical injuries, 36% and 14% for maxillofacial injuries, 16% and 9% for injuries to the head, and 35% and 45% for injuries to the chest. In the GSW group, 91% underwent computed tomography angiography (CTA), with 23% of these being positive for a vascular injury. For SWs, 74% of patients underwent CTA, with 17% positive for a vascular injury. Slightly more patients with GSWs required operative intervention than those with SWs (29% vs 26%). Conclusions Patients with GSWs to the neck have a worse outcome than those with injuries secondary to SWs. However, the proportion of neck injuries actually requiring direct surgical intervention is not increased and most cases with PNI secondary to GSWs can be

  3. A survey on spinal cord injuries resulting from stabbings; a case series study of 12 years' experience

    Directory of Open Access Journals (Sweden)

    Alireza Ahmadi

    2013-01-01

    Full Text Available BACKGROUND: Penetrating spinal cord injuries (SCIs are an uncommon injury and not reported very frequently. SCIs cause sensory, motor and genitourinary system problems or a combination of sensorimotor dysfunctions. These are among the most debilitating kinds of disorders and negatively affect quality of life, not only for the patient, but also for their family members. Therefore, the present study aims to evaluate complete or incomplete SCIs and the course of the injury and the prognosis for SCIs caused by stab wounds. METHODS: This case-series design study was performed on 57 patients attending the emergency department of Taleqani Trauma Center (Kermanshah, Iran due to SCIs caused by violent encounters involving sharp objects such as a knife, dagger, whittle and Bowie knife between 1999 and 2011. An assessment of sensory and motor functions was performed as part of the neurological examination on admission, and during the treatment, using the Frankel Classification grading system, and the results were recorded. RESULTS: The average age of patients was 27 years (SD= 7.9, Range=17 to 46 years. The results of the study showed a proportion of cervical, thoracic and lumbar injuries of 23 (40%, 24 (42% and 10 (18%, respectively. There was no case of cerebrospinal fluid leakage (CSF or infection at the wound site in the subjects. Regarding the extent of the SCI, the combined neurological assessment showed that several patients (43% had a complete SCI with no sensory and motor functions in the sacral segments and the segments below the site of injury. In 32 patients (57% incomplete injuries were observed; i.e. they showed only some degrees of sensory-motor functions that were below the neurological level. CONCLUSION: Both complete and incomplete SCIs are of great importance because the prognosis of SCI is directly associated with the location and extent of injury. It should be considered that partial recovery from SCIs is possible in few cases of

  4. A comparative audit of gunshot wounds and stab wounds to the neck in a South African metropolitan trauma service.

    Science.gov (United States)

    Madsen, A S; Laing, G L; Bruce, J L; Clarke, D L

    2016-09-01

    Introduction The aim of this comparative study of gunshot wounds (GSWs) and stab wounds (SWs) to the neck was to quantify the impact of the mechanism of injury on the outcome and management of penetrating neck injury (PNI). Methods A prospective trauma registry was interrogated retrospectively. Data were analysed pertaining to demographics and injury severity score (ISS), physiology on presentation, anatomical site of wounds and injuries sustained, investigations, management, outcome and complications. Results There were 452 SW and 58 GSW cases over the 46 months of the study. Patients with GSWs were more likely to have extracervical injuries than those with SWs (69% vs 63%). The incidence of a 'significant cervical injury' was almost twice as high in the GSW cohort (55% vs 31%). For patients with transcervical GSWs, this increased to 80%. The mean ISS was 17 for GSW and 11 for SW patients. Those in the GSW cohort presented with threatened airways and a requirement for an emergency airway three times as often as patients with SWs (24% vs 7% and 14% vs 5% respectively). The incidence among GSW and SW patients respectively was 5% and 6% for airway injuries, 12% and 8% for injuries to the digestive tract, 21% and 16% for vascular injuries, 59% and 10% for associated cervical injuries, 36% and 14% for maxillofacial injuries, 16% and 9% for injuries to the head, and 35% and 45% for injuries to the chest. In the GSW group, 91% underwent computed tomography angiography (CTA), with 23% of these being positive for a vascular injury. For SWs, 74% of patients underwent CTA, with 17% positive for a vascular injury. Slightly more patients with GSWs required operative intervention than those with SWs (29% vs 26%). Conclusions Patients with GSWs to the neck have a worse outcome than those with injuries secondary to SWs. However, the proportion of neck injuries actually requiring direct surgical intervention is not increased and most cases with PNI secondary to GSWs can be managed

  5. VIHARA DAN KOMPONENNYA SEBAGAI MITRA KERJA SEKOLAH TINGGI AGAMA BUDDHA NEGERI RADEN WIJAYA WONOGIRI JAWA TENGAH (Tinjauan Evaluasi Terhadap Tiga Wilayah Pengabdian Kepada Masyarakat STAB N Raden Wijaya

    Directory of Open Access Journals (Sweden)

    Hesty Sadtyadi

    2015-06-01

    Full Text Available Tridharma community empowerment programs through college, especially community service have been carried out by STAB N Raden Wijaya Wonogiri. The program was used to implement science acquired by the lecturers and students. Particularly, the program is to improve the ability to put themselves as a religious adviser, through religion coach training, and to improve the qualification requirements of religious teachers which are still far from the requirement, as well as the utilization and improvement of its religious infrastructure, through Vihara in three areas of community service that has been done by STAB N Raden Wijaya Wonogiri. Based on the implementation, it is necessary to evaluate community service program which has been implemented in the three areas. Evaluations of the implementation of the community service program that have been implemented seem to be successful, and the people got the good result of the program. Generally, The results of the implementation of the program can be stated to be successful

  6. Urodynamic implications of benign prostatic hyperplasia

    DEFF Research Database (Denmark)

    Jensen, K M; Andersen, J T

    1990-01-01

    By the age of 60, about 70% of men have developed benign prostatic hyperplasia (BPH), and 85%-95% of these have symptomatic dysfunction of the lower urinary tract, 10%-20% undergoing prostatectomy. Although transurethral resection of the prostate is generally considered to be a safe and effective...

  7. Laparoscopic Management of Benign Ovarian Masses

    Directory of Open Access Journals (Sweden)

    Rachana Saha

    2013-12-01

    Full Text Available Introduction: Laparoscopic surgery is one of the most common procedures performed for benign ovarian masses. The aim of the study was to analyze all benign ovarian masses treated laparoscopically to assess safety, feasibility and outcome. Methods: A prospective study was carried out at Kathmandu Medical College Teaching Hospital, Sinamangal, Nepal. All the patients undergoing laparoscopic surgery for benign ovarian masses from 1st January 2012 to 31st December 2012 were included in the study. The pre-operative findings, intra-operative findings, operative techniques and post-operative complications were analyzed. Results: Thirty-six patients were taken for the study. Two cases were excluded since intra-operatively they were tubo-ovarian masses. The most common tumor was dermoid cyst (n=13; 38.23% and endometriotic cyst (n=14; 41.17%. Out of 34 cases, five cases of endometriotic cyst (14.70% were converted to laparotomy due to severe adhesions and four cases of endometriotic cyst underwent deroofing surgery. Two cases underwent laparoscopic assisted vaginal hysterectomy with bilateral salphingo-oopherectomy. Successful cystectomies were carried out in 22 cases. None were malignant. Major complications were not noted while minor complications like port-site infection (n=3; 8.82% and subcutaneous emphysema (n=1; 2.9% were present. Conclusions: Laproscopic management of benign ovarian masses is safe and feasible.

  8. Imaging features of benign adrenal cysts

    Energy Technology Data Exchange (ETDEWEB)

    Sanal, Hatice Tuba [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey)]. E-mail: tubasanal@yahoo.com; Kocaoglu, Murat [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey); Yildirim, Duzgun [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey); Bulakbasi, Nail [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey); Guvenc, Inanc [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey); Tayfun, Cem [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey); Ucoz, Taner [Department of Radiology, Gulhane Military Medical Academy, Ankara (Turkey)

    2006-12-15

    Benign adrenal gland cysts (BACs) are rare lesions with a variable histological spectrum and may mimic not only each other but also malignant ones. We aimed to review imaging features of BACs which can be helpful in distinguishing each entity and determining the subsequent appropriate management.

  9. Benign prostatic hyperplasia: symptoms and objective interpretation

    DEFF Research Database (Denmark)

    Andersen, J T

    1991-01-01

    Considerable new knowledge about benign prostatic hyperplasia has been gained over the past two decades, particularly with regard to its natural history, hydrodynamic changes in the lower urinary tract, and the symptomatic and urodynamic results of treatment. A survey of the literature has been u...

  10. Natural history of benign prostate hyperplasia

    Institute of Scientific and Technical Information of China (English)

    WU Shi-liang; LI Ning-chen; XIAO Yun-xiang; JIN Jie; QIU Shao-peng; YE Zhang-qun; KONG Chui-ze; SUN Guang; NA Yan-qun

    2006-01-01

    Background Benign prostate hyperplasia is one of the most common diseases affecting the health of the aging males. Watchful waiting is an acceptable management strategy for benign prostate hyperplasia in which the patient is monitored by the physician but receives no active intervention. The epidemiological data on this are lacking in China. Our study was designed to evaluate the changes of signs and symptoms of patients with benign prostate hyperplasia during management by watchful waiting in China.Methods One hundred and forty-five patients with benign prostate hyperplasia aged > 50 years were enrolled in management by watchful waiting. All the patients were visited every 6 months and were given an International Prostate Symptom Score and Quality of Life questionnaire to complete. They also had uroflowmetry and were assessed using ultrasonography to get the volume of prostate, transition zone and amount of residual urine. The Student's t test, the Chi-square test, and variance analysis were used in the statistical analysis.Results All patients were visited after 6 months, the mean volume of transitional zone was found to haveincreased by 1.6 ml (P<0.01), International Prostate Symptom Score was increased by 0.8 (P<0.01) and Quality of Life was increased by 0.2 (P<0.01), and there was no statistical change in other data. Among these patients,17.9% (26/145) visited again after 12 months when the data failed to show a statistically significant difference among the three groups (0, 6, and 12 months).Conclusions After one year's follow-up, the progression of benign prostate hyperplasia was slow and the clinical data did not undergo much change.

  11. Endo-biliary stents for benign disease: not always benign after all!

    Directory of Open Access Journals (Sweden)

    Jo-Etienne Abela

    2011-11-01

    Full Text Available This case report describes the presentation, management and treatment of a patient who suffered small bowel perforation due to the migration of his biliary stent which had been inserted for benign disease.

  12. Benign Multicystic Mesothelioma in the Left Round Ligament: Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Bae, So Young; Yi, Boem Ha; Lee, Hae Kyung; Park, Seong Jin; Cho, Gyu Seok; Kwak, Jeong Ja [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

    2010-02-15

    Benign multicystic mesothelioma is a rare mesothelial lesion that forms multicystic masses in the upper abdomen, pelvis, and retroperitoneum. Most cases have a benign course. We present the ultrasound and MR findings of benign multicystic mesothelioma in the left round ligament, which caused a left inguinal hernia in a 46-year-old woman.

  13. BENIGN PAROTID TUMORS : AN EXPERIENCE IN A GENERAL SURGICAL UNIT

    Directory of Open Access Journals (Sweden)

    Vijaya

    2015-04-01

    Full Text Available Parotid tumors are mostly benign, but their evaluation and treatment require a thorough knowledge of the relevant anatomy and pathology. Surgical treatment of benign tumors is aimed at complete removal of the mass with facial nerve preservation. The aim of this study was to evaluate the post - operative complications of superficial parotidectomy in benign parotid tumors.

  14. The detonation parameters of high energy density explosive predicted with a new revised VLW EOS

    Energy Technology Data Exchange (ETDEWEB)

    Xinping, L.; Xiaohua, J. [Southwest Institut of Chemical Mat. Chengdu Sichuan (China); Xiong, W. [Xian Modern Chemistry Research Institute (China)

    1996-12-31

    Some new target explosive compounds whose detonation performance significantly exceeds that of HMX have been predicted with the new revised VLM equation of state, which includes up to the sixth viral term. The two different hypotheses have been used in the calculation; solid carbon exists in detonation products as graphite or as diamond. (authors) 10 refs.

  15. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Science.gov (United States)

    2010-07-01

    ... magazines. 75.1312 Section 75.1312 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... Blasting § 75.1312 Explosives and detonators in underground magazines. (a) The quantity of explosives kept..., explosives and detonators taken underground shall be kept in— (1) Separate, closed magazines at least 5...

  16. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and detonators outside of magazines... § 75.1313 Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other area where blasting is to be performed shall— (1) Not...

  17. Operational Characteristics of a Rotating Detonation Engine Using Hydrogen and Air

    Science.gov (United States)

    2011-06-01

    speeds but eventually transition to supersonic detonation waves in a process known as deflagration to detonation transition (DDT). The residual hot...To obtain the Hugoniot curve, Eqs. 13, 14, and 15 are combined with the following ideal gas relations (Eqs. 16 through 18) and the caloric

  18. 33 CFR 154.822 - Detonation arresters, flame arresters, and flame screens.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Detonation arresters, flame arresters, and flame screens. 154.822 Section 154.822 Navigation and Navigable Waters COAST GUARD... BULK Vapor Control Systems § 154.822 Detonation arresters, flame arresters, and flame screens. (a)...

  19. Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

    Science.gov (United States)

    Povinelli, Louis A.

    2001-01-01

    A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

  20. Detonation chemistry: an investigation of fluorine as an oxidizing moiety in explosives

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, R.R.; Ornellas, D.L.; Helm, F.H.; Coon, C.L.; Finger, M.

    1982-07-07

    We have investigated the use of fluorine in the form of the difluoramino (NF/sub 2/) group as an oxidizing moiety. Bis- and tris-difluoramino perfluorobutane, previously unknown, were especially synthesized for this study. We performed detonation calorimetry to determine the exact detonation product composition and the heat of detonation of a series of NF/sub 2/ compounds and mixtures. We then performed cylinder tests to determine their detonation performance. Similar tests on NO/sub 2/ compounds were used for comparison. For reasons of toxicity and safety, we designed and built remote mixing and loading apparati for certain of the materials. Materials were chosen to highlight certain of the detonation products. Hydrogen fluoride was found to be a favorable detonation product compared with H/sub 2/O; CO/sub 2/ outperforms CF/sub 4/ at all cylinder expansion ratios; and Al/sub 2/O/sub 3/ was a favorable detonation product compared to AlF/sub 3/. The most important result is better understanding of the mechanism of reaction of small-particle aluminum in a detonation.

  1. Plasma-assisted ignition and deflagration-to-detonation transition.

    Science.gov (United States)

    Starikovskiy, Andrey; Aleksandrov, Nickolay; Rakitin, Aleksandr

    2012-02-13

    Non-equilibrium plasma demonstrates great potential to control ultra-lean, ultra-fast, low-temperature flames and to become an extremely promising technology for a wide range of applications, including aviation gas turbine engines, piston engines, RAMjets, SCRAMjets and detonation initiation for pulsed detonation engines. The analysis of discharge processes shows that the discharge energy can be deposited into the desired internal degrees of freedom of molecules when varying the reduced electric field, E/n, at which the discharge is maintained. The amount of deposited energy is controlled by other discharge and gas parameters, including electric pulse duration, discharge current, gas number density, gas temperature, etc. As a rule, the dominant mechanism of the effect of non-equilibrium plasma on ignition and combustion is associated with the generation of active particles in the discharge plasma. For plasma-assisted ignition and combustion in mixtures containing air, the most promising active species are O atoms and, to a smaller extent, some other neutral atoms and radicals. These active particles are efficiently produced in high-voltage, nanosecond, pulse discharges owing to electron-impact dissociation of molecules and electron-impact excitation of N(2) electronic states, followed by collisional quenching of these states to dissociate the molecules. Mechanisms of deflagration-to-detonation transition (DDT) initiation by non-equilibrium plasma were analysed. For longitudinal discharges with a high power density in a plasma channel, two fast DDT mechanisms have been observed. When initiated by a spark or a transient discharge, the mixture ignited simultaneously over the volume of the discharge channel, producing a shock wave with a Mach number greater than 2 and a flame. A gradient mechanism of DDT similar to that proposed by Zeldovich has been observed experimentally under streamer initiation.

  2. A numerical study of two- and three-dimensional detonation dynamics of pulse detonation engine by the CE/SE method

    Institute of Scientific and Technical Information of China (English)

    Chunsheng Weng; Jay P. Gore

    2005-01-01

    In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of Pulse Detonation Engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved in two steps. The detailed analysis of computational results of a PDE with a single detonation tube and a PDE with five detonation tubes are given in this paper. Complex wave systems are observed inside and outside a PDE. For a PDE with 5 detonation tubes, there is a big bow shock produced from a number of little shocks near the open ends of tubes. A lot of vortexes interact with shocks and a large expansion wave propagates forward and backward with respect to the PDE in a semi-oval shape.

  3. Application of the CE/SE Method to a Two-Phase Detonation Model in Porous Media

    Institute of Scientific and Technical Information of China (English)

    DONG He-Fei; HONG Tao; ZHANG De-Liang

    2011-01-01

    We extend the conservation-element and solution-element method to simulate a two-phase detonation model in porous media. The accuracy of the method is validated by calculating an inert compaction problem. The main characteristics of piston-driven detonation phenomena, including the compaction wave, the onset of combustion,and the transition to detonation, could be predicted successfully.

  4. An Explosives Products Thermodynamic Equation of State Appropriate for Material Acceleration and Overdriven Detonation: Theoretical Background and Formulation

    Science.gov (United States)

    1991-07-01

    9 i 1 Normally, the equation of state parameters are chosen so that E. has the value E. = p0AH, where AH is the heat of detonation . This is consistent...Initial Specific Volume a Gruneisen Parameter 7 Adiabatic Gamnma C Sound Speed D) Detonation Velocity U mMass Velocity A 1l Heat of Detonation B ;., R xi

  5. Benign paroxysmal positional vertigo following septorhinoplasty.

    Science.gov (United States)

    Koc, Eltaf Ayca Ozbal; Koc, Bulent; Eryaman, Esra; Ozluoglu, Levent N

    2013-01-01

    We present 2 cases of benign paroxysmal positional vertigo (BPPV) following septorhinoplasty. Benign paroxysmal positional vertigo following septorhinoplasty is an unusual entity. Two young women who had difficulty in breathing and nasal deformity underwent septorhinoplasty. On the second and the third postoperative days, the patients experienced vertigo that was induced by position changes. Both patients had neither preexisting ear disease nor vertigo before the surgery. All the examinations were normal. With Dix-Hallpike maneuver, which is the criterion-standard test, the characteristic nystagmus was observed. Right posterior canal BPPV was diagnosed, and they were both treated with Epley canalith repositioning maneuver. Publications related to postsurgical vertigo are available in literature, but it is still an underdiagnosed disorder. We would like to mention about this rare entity and inform the surgeons that they must keep in mind that a patient who is complaining about vertigo or dizziness after the surgery should be observed and investigated for BPPV.

  6. Benign solitary solid cold thyroid nodules

    DEFF Research Database (Denmark)

    Døssing, Helle; Bennedbaek, Finn Noe; Karstrup, Steen;

    2002-01-01

    PURPOSE: To evaluate the effects of ultrasonography (US)-guided interstitial laser photocoagulation (ILP) on the volume of benign solitary solid cold thyroid nodules and any nodule-related symptoms. MATERIALS AND METHODS: ILP was performed in 16 patients with normal thyroid function and a solid...... to evaluate the size of the untreated thyroid nodule. RESULTS: In the 16 patients treated with ILP, the mean thyroid nodule volume decreased from 10 to 5.4 mL (P .... Pressure symptoms were significantly reduced (P =.0002) after 6 months. The treatment was well-tolerated in all patients. No significant change in thyroid nodule volume was seen in the control group. CONCLUSION: US-guided ILP could become a useful nonsurgical alternative in the treatment of the benign...

  7. Characteristics of benign lymphoadenosis of oral mucosa

    Institute of Scientific and Technical Information of China (English)

    Shu-Xia Li; Shi-Feng Yu; Kai-Hua Sun

    2005-01-01

    AIM: To investigate the pathological characteristics and carcinogenesis mechanism of benign lymphoadenosis of oral mucosa (BLOM).METHODS: The expressions of Ki-67, CD34 and apoptosis were evaluated by immunohistochemical SP staining in 64 paraffin-embedded tissue samples. Of them, 9 were from BLOM with dysplasia, 15 from BLOM without dysplasia,15 from oral squamous cell carcinoma (OSCC), 15 from oral precancerosis, and 10 from normal tissues. Cell proliferation, apoptosis and angiogenesis of tissue samples were also analyzed.RESULTS: The expression of Ki-67 in BLOM with dysplasia,oral precancerosis and OSCC was significantly higher than in BLOM without dysplasia and normal mucosa. The microvascular density (MVD) in BLOM with and without dysplasia, oral precancerosis, and OSCC was significantly higher than in normal mucosa. Apoptosis in BLOM and oral precancerosis was significantly higher than in OSCC and normal mucosa.CONCLUSION: Benign lymphoadenosis of oral mucosa has potentialities of cancerization.

  8. Endoscopic therapy of benign biliary strictures

    Institute of Scientific and Technical Information of China (English)

    Joel R Judah; Peter V Draganov

    2007-01-01

    Benign biliary strictures are being increasingly treated with endoscopic techniques. The benign nature of the stricture should be first confirmed in order to ensure appropriate therapy. Surgery has been the traditional treatment, but there is increasing desire for minimally invasive endoscopic therapy. At present, endoscopy has become the first line approach for the therapy of postliver transplant anastomotic strictures and distal (Bismuth Ⅰ and Ⅱ) post-operative strictures. Strictures related to chronic pancreatitis have proven more difficult to treat,and endoscopic therapy is reserved for patients who are not surgical candidates. The preferred endoscopic approach is aggressive treatment with gradual dilation of the stricture and insertion of multiple plastic stents. The use of uncovered self expandable metal stents should be discouraged due to poor long-term results. Treatment with covered metal stents or bioabsorbable stents warrants further evaluation. This area of therapeutic endoscopy provides an ongoing opportunity for fresh research and innovation.

  9. Introduction to Physics and Chemistry of Combustion Explosion, Flame, Detonation

    CERN Document Server

    Liberman, Michael A

    2008-01-01

    Most of the material covered in this book deals with the fundamentals of chemistry and physics of key processes and fundamental mechanisms for various combustion and combustion related phenomena in gaseous combustible mixture. It provides the reader with basic knowledge of burning processes and mechanisms of reaction wave propagation. The combustion of a gas mixture (flame, explosion, detonation) is necessarily accompanied by motion of the gas. The process of combustion is therefore not only a chemical phenomenon but also one of gas dynamics. The material selection focuses on the gas phase and

  10. Effects of hypothetical improvised nuclear detonation on the electrical infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Christopher L.; Eubank, Stephen; Evrenosoglu, C. Yaman; Marathe, Achla; Marathe, Madhav V.; Phadke, Arun; Thorp, James; Vullikanti, Anil [Virginia Tech, Blacksburg, VA (United States). Network Dynamics and Simulation Science Lab.

    2013-07-01

    We study the impacts of a hypothetical improvised nuclear detonation (IND) on the electrical infrastructure and its cascading effects on other urban inter-dependent infrastructures of a major metropolitan area in the US. We synthesize open source information, expert knowledge, commercial software and Google Earth data to derive a realistic electrical transmission and distribution network spanning the region. A dynamic analysis of the geo-located grid is carried out to determine the cause of malfunction of components, and their short-term and long-term effect on the stability of the grid. Finally a detailed estimate of the cost of damage to the major components of the infrastructure is provided.

  11. Deflagration-to-Detonation Transition in Unconfined Media

    Science.gov (United States)

    Poludnenko, Alexei; Gardiner, Thomas; Oran, Elaine

    2011-11-01

    Deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems on Earth to astrophysical thermonuclear supernovae explosions. In recent years, substantial progress has been made in elucidating the nature of this process in confined systems with walls, obstacles, etc. It remains unclear, however, whether a subsonic turbulent flame in an unconfined environment can undergo a DDT. We present simulations of premixed flames in stoichiometric H2-air and CH4-air mixtures interacting with high-intensity turbulence. These calculations demonstrate the DDT in unconfined systems unassisted by shocks or obstacles. We discuss the mechanism of this process and its implications.

  12. Deflagration-to-Detonation Transition Control by Nanosecond Gas Discharges

    Science.gov (United States)

    2008-04-07

    to a voltage of 37 kV. A high-voltage pulse was formed on the electrode when the feeding line had been grounded by the thyratron (5). The pulse...width – 1–3 µs, rise time – ∼100 ns. The rise time was determined by thyratron switching time. The energy input in this case was limited by the energy...Kapila, A. K., Schwendeman, D. W., Quirk, J. J., and Hawa, T., “Mech- anisms of Detonation Formation due to a Temperature Gradient,” Com- bustion Theory and Modelling , Vol. 6, No. 4, 2002, pp. 553–594. 74

  13. Shock wave reflection induced detonation (SWRID) under high pressure and temperature condition in closed cylinder

    Science.gov (United States)

    Wang, Z.; Qi, Y.; Liu, H.; Zhang, P.; He, X.; Wang, J.

    2016-09-01

    Super-knock is one of the major obstacles for improving power density in advanced internal combustion engines (ICE). This work studied the mechanism of super-knock initiation using a rapid compression machine that simulated conditions relevant to ICEs and provided excellent optical accessibility. Based on the high-speed images and pressure traces of the stoichiometric iso-octane/oxygen/nitrogen combustion under high-temperature and high-pressure conditions, it was observed that detonation was first initiated in the near-wall region as a result of shock wave reflection. Before detonation was initiated, the speed of the combustion wave front was less than that of the Chapman-Jouguet (C-J) detonation speed (around 1840 m/s). In the immediate vicinity of the initiation, the detonation speed was much higher than that of the C-J detonation.

  14. Numerical investigation on detonation cell evolution in a channel with area-changing cross section

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ The two-dimensional cellular detonation propagating in a channel with area- changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow expansion and compression on the cellular detonation cell were investigated to illustrate the mechanism of the transverse wave development and the cellular detonation cell evolution. By examining gas composition variations behind the leading shock, the chemical reaction rate, the reaction zone length, and thermodynamic parameters, two kinds of the abnormal detonation waves were identified. To explore their development mechanism, chemical reactions, reflected shocks and rarefaction waves were discussed, which interact with each other and affect the cellular detonation in different ways.

  15. Deflagration-to-detonation transition in gases in tubes with cavities

    Science.gov (United States)

    Smirnov, N. N.; Nikitin, V. F.; Phylippov, Yu. G.

    2010-12-01

    The existence of a supersonic second combustion mode — detonation — discovered by Mallard and Le Chatelier and by Berthélot and Vieille in 1881 posed the question of mechanisms for transition from one mode to the other. In the period 1959-1969, experiments by Salamandra, Soloukhin, Oppenheim, and their coworkers provided insights into this complex phenomenon. Since then, among all the phenomena related to combustion processes, deflagration-to-detonation transition is, undoubtedly, the most intriguing one. Deflagration-to-detonation transition (DDT) in gases is connected with gas and vapor explosion safety issues. Knowing mechanisms of detonation onset control is of major importance for creating effective mitigation measures addressing two major goals: to prevent DDT in the case of mixture ignition, or to arrest the detonation wave in the case where it has been initiated. A new impetus to the increase in interest in deflagration-to-detonation transition processes was given by the recent development of pulse detonation devices. The probable application of these principles to creation of a new generation of engines put the problem of effectiveness of pulse detonating devices at the top of current research needs. The effectiveness of the pulse detonation cycle turned out to be the key factor characterizing the Pulse Detonation Engine (PDE), whose operation modes were shown to be closely related to periodical onset and degeneration of a detonation wave. Those unsteady-state regimes should be self-sustained to guarantee a reliable operation of devices using the detonation mode of burning fuels as a constitutive part of their working cycle. Thus deflagration-to-detonation transition processes are of major importance for the issue. Minimizing the predetonation length and ensuring stability of the onset of detonation enable one to increase the effectiveness of a PDE. The DDT turned out to be the key factor characterizing the PDE operating cycle. Thus, the problem of

  16. Simple correlation for predicting detonation velocity of ideal and non-ideal explosives.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2009-07-30

    This paper describes a simple method for prediction of detonation velocity of ideal and non-ideal explosives. A non-ideal aluminized and nitrated explosive can have Chapman-Jouguet detonation velocity significantly different from that expected from existing thermodynamic computer codes for equilibrium and steady-state calculations. Detonation velocity of explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from values of a, b, c, d, e and a specific structural parameter without using any assumed detonation products, heat of formation and experimental data. Predicted detonation velocities by this procedure for ideal and non-ideal explosives show good agreement with respect to experimental values as compared to computed results of BKWR and BKWS equations of state.

  17. Theoretical studies on the structures and detonation properties of nitramine explosives containing benzene ring.

    Science.gov (United States)

    Zhao, GuoZheng; Lu, Ming

    2012-06-01

    The nitramine compounds containing benzene ring were optimized to obtain their molecular geometries and electronic structures at DFT-B3LYP/6-31+G(d) level. The theoretical molecular density (ρ), heat of formation (HOF), energy gap (ΔE(LUMO-HOMO)), charge on the nitro group (-Q(NO2)), detonation velocity (D) and detonation pressure (P), estimated using Kamlet-Jacobs equations, showed that the detonation properties of these compounds were excellent. It is found that there are good linear relationships between density, heat of formation, detonation velocity, detonation pressure and the number of nitro group. The simulation results reveal that molecule G performs similarly to famous explosive HMX, and molecule H outperforms HMX. According to the quantitative standard of energetics as an HEDC (high energy density compound), molecule H essentially satisfies this requirement. These results provide basic information for molecular design of novel high energetic density compounds.

  18. Numerical investigation on detonation cell evolution in a channel with area-changing cross section

    Institute of Scientific and Technical Information of China (English)

    DENG; Bo

    2007-01-01

    The two-dimensional cellular detonation propagating in a channel with area- changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow expansion and compression on the cellular detonation cell were investigated to illustrate the mechanism of the transverse wave development and the cellular detonation cell evolution. By examining gas composition variations behind the leading shock, the chemical reaction rate, the reaction zone length, and thermodynamic parameters, two kinds of the abnormal detonation waves were identified. To explore their development mechanism, chemical reactions, reflected shocks and rarefaction waves were discussed, which interact with each other and affect the cellular detonation in different ways.  ……

  19. Research on design and firing performance of Si-based detonator

    Institute of Scientific and Technical Information of China (English)

    Rui-zhen XIE; Xiao-ming REN; Lan LIU; Yan XUE; Dong-xiao FU; Rui ZHANG

    2014-01-01

    For the chip integration of MEMS (micro-electromechanical system) safety and arming device, a miniature detonator needs to be developed to reduce the weight and volume of explosive train. A Si-based micro-detonator is designed and fabricated, which meets the requirement of MEMS safety and arming device. The firing sensitivity of micro-detonator is tested according to GJB/z377A-94 sensitivity test methods:Langlie. The function time of micro-detonator is measured using wire probe and photoelectric transducer. The result shows the average firing voltage is 6.4 V when the discharge capacitance of firing electro-circuit is 33 mF. And the average function time is 5.48 ms. The firing energy actually utilized by Si-based micro-detonator is explored.

  20. Percutaneous treatment of benign bile duct strictures

    Energy Technology Data Exchange (ETDEWEB)

    Koecher, Martin [Department of Radiology, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)]. E-mail: martin.kocher@seznam.cz; Cerna, Marie [Department of Radiology, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Havlik, Roman [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Kral, Vladimir [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Gryga, Adolf [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic); Duda, Miloslav [Department of Surgery, University Hospital, I.P.Pavlova 6, 775 20 Olomouc (Czech Republic)

    2007-05-15

    Purpose: To evaluate long-term results of treatment of benign bile duct strictures. Materials and methods: From February 1994 to November 2005, 21 patients (9 men, 12 women) with median age of 50.6 years (range 27-77 years) were indicated to percutaneous treatment of benign bile duct stricture. Stricture of hepatic ducts junction resulting from thermic injury during laparoscopic cholecystectomy was indication for treatment in one patient, stricture of hepaticojejunostomy was indication for treatment in all other patients. Clinical symptoms (obstructive jaundice, anicteric cholestasis, cholangitis or biliary cirrhosis) have appeared from 3 months to 12 years after surgery. Results: Initial internal/external biliary drainage was successful in 20 patients out of 21. These 20 patients after successful initial drainage were treated by balloon dilatation and long-term internal/external drainage. Sixteen patients were symptoms free during the follow-up. The relapse of clinical symptoms has appeared in four patients 9, 12, 14 and 24 months after treatment. One year primary clinical success rate of treatment for benign bile duct stricture was 94%. Additional two patients are symptoms free after redilatation (15 and 45 months). One patient is still in treatment, one patient died during secondary treatment period without interrelation with biliary intervention. The secondary clinical success rate is 100%. Conclusion: Benign bile duct strictures of hepatic ducts junction or biliary-enteric anastomosis are difficult to treat surgically and endoscopically inaccessible. Percutaneous treatment by balloon dilatation and long-term internal/external drainage is feasible in the majority of these patients. It is minimally invasive, safe and effective.

  1. Benign paroxysmal positional vertigo recurrence and persistence

    OpenAIRE

    Ricardo S. Dorigueto; Mazzetti,Karen R; Gabilan,Yeda Pereira L; Ganança, Fernando Freitas [UNIFESP

    2009-01-01

    Benign paroxysmal positional vertigo (BPPV) is one of the most common vestibular disorders. AIM: To study the recurrence and persistence of BPPV in patients treated with canalith repositioning maneuvers (CRM) during the period of one year. STUDY DESIGN: longitudinal contemporary cohort series. MATERIALS AND METHODS: One hundred patients with BPPV were followed up during 12 months after a treatment with CRM. Patients were classified according to disease evolution. Aquatic physiotherapy for ves...

  2. [Surgical treatment of benign paroxysmal positional vertigo].

    Science.gov (United States)

    Zaugg, Y; Grosjean, P; Maire, R

    2012-10-03

    Benign paroxysmal positional vertigo (BPPV) is a common disorder that presents to the general practitioner. This condition represents one of the most common causes of peripheral vertigo. The diagnosis is made on clinical grounds. The treatment relies on repositioning maneuvers with relief of symptoms that occur in a few weeks in the majority of the cases. Rarely, patients are incapacitated by persistent or recurrent BPPV despite multiple repositioning maneuvers. In these cases, surgical therapies are available which provide excellent results.

  3. Large Penile Mass With Unusual Benign Histopathology

    Directory of Open Access Journals (Sweden)

    Nate Johnson

    2015-09-01

    Full Text Available Pseudoepitheliomatous hyperplasia is an extremely rare condition presenting as a lesion on the glans penis in older men. Physical exam without biopsy cannot differentiate malignant from nonmalignant growth. We report a case of large penile mass in an elderly male with a history of lichen sclerosis, highly suspicious for malignancy. Subsequent surgical removal and biopsy demonstrated pseudoepitheliomatous hyperplasia, an unusual benign histopathologic diagnosis with unclear prognosis. We review the literature and discuss options for treatment and surveillance.

  4. [Benign prostatic hypertrophy and prostate cancer].

    Science.gov (United States)

    Mourey, Loïc; Doumerc, Nicolas; Gaudin, Clément; Gérard, Stéphane; Balardy, Laurent

    2014-01-01

    Prostatic diseases are extremely common, especially in older men. Amongst them, benign prostatic hypertrophy may affect significantly the quality of life of patients by the symptoms it causes. It requires appropriate care. Prostate cancer is the second most common cancer in men after lung cancer and the fifth leading cause of cancer deaths in the world. It affects preferentially older men. An oncogeriatric approach is required for personalised care.

  5. Laparoscopic resection of retroperitoneal benign neurilemmoma

    Science.gov (United States)

    Park, Joon Seong; Kang, Chang Moo; Yoon, Dong Sup; Lee, Woo Jung

    2017-01-01

    Purpose The aim of this study was to verify that laparoscopic resection for treating retroperitoneal benign neurilemmoma (NL) is expected to be favorable for complete resection of tumor with technical feasibility and safety. Methods We retrospectively analyzed 47 operations for retroperitoneal neurogenic tumor at Yonsei University College of Medicine, Severance Hospital and Gangnam Severance Hospital between January 2005 and September 2015. After excluding 21 patients, the remaining 26 were divided into 2 groups: those who underwent open surgery (OS) and those who underwent laparoscopic surgery (LS). We compared clinicopathological features between the 2 groups. Results There was no significant difference in operation time, estimated blood loss, transfusion, complication, recurrence, or follow-up period between 2 groups. Postoperative hospital stay was significantly shorter in the LS group versus the OS group (OS vs. LS, 7.00 ± 3.43 days vs. 4.50 ± 2.16 days; P = 0.031). Conclusion We suggest that laparoscopic resection of retroperitoneal benign NL is feasible and safe by obtaining complete resection of the tumor. LS for treating retroperitoneal benign NL could be useful with appropriate laparoscopic technique and proper patient selection.

  6. [Acute benign cerebral angiopathy. 6 cases].

    Science.gov (United States)

    Rousseaux, P; Scherpereel, B; Bernard, M H; Guyot, J F

    1983-10-08

    The 6 cases reported here constitute, with 5 previously published cases, a special nosological entity tentatively called "acute benign cerebral angiopathy" by the authors. These 11 cases have in common certain radiological and clinical features. Arteriography shows segmental, multifocal and assymetrical stenoses involving the cerebral arteries between Willis' circle and the terminal arterioles and looking like "strings of sausages". The lesions disappear within one month and present the radiological characteristics of arteritis of medium caliber vessels. The clinical symptoms are suggestive of meningeal haemorrhage or acute cerebromeningeal oedema, with acute repetitive attacks of severe headache and agitation with obnubilation; epileptic seizures and transient neurological deficit may occur. True meningeal haemorrhage confirmed by lumbar puncture is seen in nearly one half of the cases; it seems to be due to alterations in the blood-brain barrier induced by the angiopathy. Intracerebral haematoma may develop, but the disease is usually benign and regresses spontaneously in a few days. None of the usual causes of cerebral arteritis (intra-cranial infection, collagen disease, allergic or toxic angitis) has been found. Pseudo-arteritis (notably spasm of ruptured arterial aneurysms) has been excluded. No aetiological factor common to the 11 cases reported has been elicited, although 6 of the patients had recently given birth and our 6 patients had benign virus infection before or during the clinical manifestations of the disease. In the authors' opinion, the most rewarding line of research would be the role of short acute attacks of arterial hypertension.

  7. Environmentally benign silicon solar cell manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S. [National Renewable Energy Lab., Golden, CO (United States); Gee, J.M. [Sandia National Labs., Albuquerque, NM (United States); Menna, P. [National Agency for New Technologies Energy and Environment, Portici (Italy); Strebkov, D.S.; Pinov, A.; Zadde, V. [Intersolarcenter, Moscow (Russian Federation)

    1998-09-01

    The manufacturing of silicon devices--from polysilicon production, crystal growth, ingot slicing, wafer cleaning, device processing, to encapsulation--requires many steps that are energy intensive and use large amounts of water and toxic chemicals. In the past two years, the silicon integrated-circuit (IC) industry has initiated several programs to promote environmentally benign manufacturing, i.e., manufacturing practices that recover, recycle, and reuse materials resources with a minimal consumption of energy. Crystalline-silicon solar photovoltaic (PV) modules, which accounted for 87% of the worldwide module shipments in 1997, are large-area devices with many manufacturing steps similar to those used in the IC industry. Obviously, there are significant opportunities for the PV industry to implement more environmentally benign manufacturing approaches. Such approaches often have the potential for significant cost reduction by reducing energy use and/or the purchase volume of new chemicals and by cutting the amount of used chemicals that must be discarded. This paper will review recent accomplishments of the IC industry initiatives and discuss new processes for environmentally benign silicon solar-cell manufacturing.

  8. An Equilibrium-Based Model of Gas Reaction and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, L.D.

    2000-04-01

    During gaseous diffusion plant operations, conditions leading to the formation of flammable gas mixtures may occasionally arise. Currently, these could consist of the evaporative coolant CFC-114 and fluorinating agents such as F2 and ClF3. Replacement of CFC-114 with a non-ozone-depleting substitute is planned. Consequently, in the future, the substitute coolant must also be considered as a potential fuel in flammable gas mixtures. Two questions of practical interest arise: (1) can a particular mixture sustain and propagate a flame if ignited, and (2) what is the maximum pressure that can be generated by the burning (and possibly exploding) gas mixture, should it ignite? Experimental data on these systems, particularly for the newer coolant candidates, are limited. To assist in answering these questions, a mathematical model was developed to serve as a tool for predicting the potential detonation pressures and for estimating the composition limits of flammability for these systems based on empirical correlations between gas mixture thermodynamics and flammability for known systems. The present model uses the thermodynamic equilibrium to determine the reaction endpoint of a reactive gas mixture and uses detonation theory to estimate an upper bound to the pressure that could be generated upon ignition. The model described and documented in this report is an extended version of related models developed in 1992 and 1999.

  9. Separation and characterisation of detonation nanodiamond by capillary zone electrophoresis.

    Science.gov (United States)

    Duffy, Emer; Mitev, Dimitar P; Nesterenko, Pavel N; Kazarian, Artaches A; Paull, Brett

    2014-07-01

    A new method for the characterisation of purified detonation nanodiamond (DND) using CZE has been developed. The influence of BGE conditions on electrophoretic mobility, peak shape and particle aggregation was investigated, with resultant observations supported by zeta potential approximations and particle size measurements. Sodium tetraborate (pH 9.3), Tris (pH 9.3) and sodium phosphate (pH 7) were used in studying the BGE concentration effect on a commercial source of chemically stabilised DND. The BGE concentration had a strong effect on the stability of DND in suspension. The formation of aggregates of various sizes was observed as BGE concentration increased. The effect of pH on the electromigration of DND was examined using sodium phosphate (pH 8 and 10). The CZE method was subsequently applied to four different DND samples, which had undergone different routes of purification following detonation synthesis. Each sample produced a unique electrophoretic peak or profile in sodium tetraborate buffer (pH 9.3), such that the actual separation of DND samples from different sources could be achieved.

  10. Microwave Diagnostics of Shock Wave and Detonation Processes

    Science.gov (United States)

    Mikhaylov, Anatoly; Belsky, Vladimir; Bogdanov, Evgeny; Rodionov, Alexey; Sedov, Alexander; Khvorostin, Vladimir; Russian Federal Nuclear Center-Vniief 607190, Sarov, Nizhniy Novgorod Reg., Russia Team

    2013-06-01

    The physical bases of laser and microwave Doppler interferometry are the same - measurements of the Doppler shift of probing electromagnetic frequency, reflected from a moving surface. However, using probing wavelength 4 orders of magnitude longer, microwave diagnostics has some specific advantages as compared with laser diagnostics, namely: measurements inside the microwave-transparent media, which spectrum is much more wide than the spectrum of optically transparent media; for microwave measurements the reflecting surfaces of media, but all jumps of medium parameters - density, dielectric permittivity, conductivity; for microwave technique due to its wavelength all practically important hydrodynamical jumps are smooth. The results of application of the microwave technique were presented in the paper, which demonstrate capabilities of diagnostics of various dynamic processes using single equipment, namely: liners and massive objects launching; shock-to-detonation transition in HE; propagation of steady detonation waves; laminar HE combustion etc. In all conducted investigations the using of the microwave technique gives a big amount of interesting experimental information which is inaccessible for the other traditional experimental techniques.

  11. Initiation of Detonation in Explosives by Impact of Projectiles

    Directory of Open Access Journals (Sweden)

    H.S. Yadav

    2006-04-01

    Full Text Available This paper presents a study of initiation of detonation in explosives by the impact ofprojectiles. The shock wave produced by the impact of projectiles has been considered as thestimulus for initiation of detonation. Three types of projectiles, namely (i flyer plate, (ii flatendedrod, and (iii round-ended rod or a shaped charge jet, have been considered to impact andproduce a shock wave in the explosives. Deriving relations for the parameters of impact-generatedshock wave in the explosives and projectiles, and the sound velocity in the compressed explosives,it has been shown that the difference of kinetic energy of the flyer plate before and after theimpact, which is equal to the total energy of the shock wave in the explosives, leads to criticalenergy criterion for shock initiation of explosives. In this study, the critical criterion has beenused to derive the relations for initiation of explosives by a shaped charge jet, Vj2 D = K0 , whereV j and D denote the velocity and diameter of the jet, and K0 is a constant of the explosive.

  12. Modeling the kinetics of carbon coagulation in explosives detonation

    Science.gov (United States)

    Ree, F. H.; Viecelli, J. A.; Glosli, J. N.

    1998-05-01

    A typical insensitive high explosive such as LX-17 has a large carbon content. The detonation behavior of these explosives is affected by a slow coagulation of carbon atoms by diffusion and their possible transformation from one chemical bonding type to another. We have used the Brenner bond order potential to compute the melting line of diamond at high pressure and high temperature by molecular dynamics and Monte Carlo simulations, with the goal to refine the potential for the study of the kinetics of the graphite diamond transition. The slow diffusion-controlled kinetics of carbon clusters has been examined by including a time-dependent surface correction to the Gibbs free energy of these clusters in the nonequilibrium CHEQ code. We also propose a new explosive burn model which incorporates a partial release of the heat of detonation in a fast reaction zone, followed by a diffusion-limited release of the remaining energy. Hydrodynamic applications of the new burn model to LX-17 show that computed expansion and compression results both agree closely with experimental data.

  13. Molecular-dynamics study of detonation. II. The reaction mechanism

    Science.gov (United States)

    Rice, Betsy M.; Mattson, William; Grosh, John; Trevino, S. F.

    1996-01-01

    In this work, we investigate mechanisms of chemical reactions that sustain an unsupported detonation. The chemical model of an energetic crystal used in this study consists of heteronuclear diatomic molecules that, at ambient pressure, dissociate endothermically. Subsequent association of the products to form homonuclear diatomic molecules provides the energy release that sustains the detonation. A many-body interaction is used to simulate changes in the electronic bonding as a function of local atomic environment. The consequence of the many-body interaction in this model is that the intramolecular bond is weakened with increasing density. The mechanism of the reaction for this model was extracted by investigating the details of the molecular properties in the reaction zone with two-dimensional molecular dynamics. The mechanism for the initiation of the reaction in this model is pressure-induced atomization. There was no evidence of excitation of vibrational modes to dissociative states. This particular result is directly attributable to the functional form and choice of parameters for this model, but might also have more general applicability.

  14. Type Ia Supernovae from Merging White Dwarfs I. Prompt Detonations

    CERN Document Server

    Moll, Rainer; Kasen, Daniel; Woosley, Stan

    2013-01-01

    Merging white dwarfs are a possible progenitor of Type Ia supernovae (SNe Ia). While it is not entirely clear if and when an explosion is triggered in such systems, numerical models suggest that a detonation might be initiated before the stars have coalesced to form a single compact object. Here we study such "peri-merger" detonations by means of numerical simulations, modeling the disruption and nucleosynthesis of the stars until the ejecta reach the coasting phase. Synthetic light curves and spectra are generated for comparison with observations. Three models are considered with primary masses 0.96 Msun, 1.06 Msun, and 1.20 Msun. Of these, the 0.96 Msun dwarf merging with an 0.81 Msun companion, with a Ni56 yield of 0.58 Msun, is the most promising candidate for reproducing common SNe Ia. The more massive mergers produce unusually luminous SNe Ia with peak luminosities approaching those attributed to "super-Chandrasekhar" mass SNe Ia. While the synthetic light curves and spectra of some of the models resemb...

  15. Finite element code development for modeling detonation of HMX composites

    Science.gov (United States)

    Duran, Adam V.; Sundararaghavan, Veera

    2017-01-01

    In this work, we present a hydrodynamics code for modeling shock and detonation waves in HMX. A stable efficient solution strategy based on a Taylor-Galerkin finite element (FE) discretization was developed to solve the reactive Euler equations. In our code, well calibrated equations of state for the solid unreacted material and gaseous reaction products have been implemented, along with a chemical reaction scheme and a mixing rule to define the properties of partially reacted states. A linear Gruneisen equation of state was employed for the unreacted HMX calibrated from experiments. The JWL form was used to model the EOS of gaseous reaction products. It is assumed that the unreacted explosive and reaction products are in both pressure and temperature equilibrium. The overall specific volume and internal energy was computed using the rule of mixtures. Arrhenius kinetics scheme was integrated to model the chemical reactions. A locally controlled dissipation was introduced that induces a non-oscillatory stabilized scheme for the shock front. The FE model was validated using analytical solutions for SOD shock and ZND strong detonation models. Benchmark problems are presented for geometries in which a single HMX crystal is subjected to a shock condition.

  16. Quantum Phenomena in Ignition and Detonation at Elevated Density

    Science.gov (United States)

    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.

  17. On the verification and validation of detonation models

    Science.gov (United States)

    Quirk, James

    2013-06-01

    This talk will consider the verification and validation of detonation models, such as Wescott-Stewart-Davis (Journal of Applied Physics. 2005), from the perspective of the American Institute of Aeronautics and Astronautics policy on numerical accuracy (AIAA J. Vol. 36, No. 1, 1998). A key aspect of the policy is that accepted documentation procedures must be used for journal articles with the aim of allowing the reported work to be reproduced by the interested reader. With the rise of electronic documents, since the policy was formulated, it is now possible to satisfy this mandate in its strictest sense: that is, it is now possible to run a comptuational verification study directly in a PDF, thereby allowing a technical author to report numerical subtleties that traditionally have been ignored. The motivation for this document-centric approach is discussed elsewhere (Quirk2003, Adaptive Mesh Refinement Theory and Practice, Springer), leaving the talk to concentrate on specific detonation examples that should be of broad interest to the shock-compression community.

  18. Detonation Output Properties of D-shape Structure

    Directory of Open Access Journals (Sweden)

    Ji-feng WEI

    2014-09-01

    Full Text Available The detonation wave propagation and output properties have been analyzed for D-shape structure. Four initiation modes were designed to compare wavefront profiles and output pressure distribution. Simulation results show that three-array-nine-point initiation mode (Mode-III brings about the most match-up wave front for D-shape structure. Detonation output properties have great influence on fragment ejection velocity and distribution density. The statistical results reveal that fragment parameters of Mode-III are the largest. Compared with Mode-III, the kinetic energies of other three modes decrease by 31.6 per cent, 19.6 per cent, 4.5 per cent, respectively. The computational values and normal curve of fragments distribution are obtained. From these analyses, it can be concluded that initiation mode has great influence on output parameters of fragments. With the optimal initiation Mode-III, ideal hitting angle should be within the range of -10° to 10°, the probability of distribution density would be close to 70 per cent.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.484-489, DOI:http://dx.doi.org/10.14429/dsj.64.4746

  19. Near-limit propagation of gaseous detonations in narrow annular channels

    Science.gov (United States)

    Gao, Y.; Ng, H. D.; Lee, J. H. S.

    2017-03-01

    New results on the near-limit behaviors of gaseous detonations in narrow annular channels are reported in this paper. Annular channels of widths 3.2 and 5.9 mm were made using circular inserts in a 50.8 mm-diameter external tube. The length of each annular channel was 1.8 m. Detonations were initiated in a steel driver tube where a small volume of a sensitive C2H2+ 2.5O2 mixture was injected to facilitate detonation initiation. A 2 m length of circular tube with a 50.8 mm diameter preceded the annular channel so that a steady Chapman-Jouguet (CJ) detonation was established prior to entering the annular channel. Four detonable mixtures of C2H2 {+} 2.5O2 {+} 85 % Ar, C2H2 {+} 2.5O2 {+} 70 % Ar, C3H8 {+} 5O2, and CH4 {+} 2O2 were used in the present study. Photodiodes spaced 10 cm throughout the length of both the annular channel and circular tube were used to measure the detonation velocity. In addition, smoked foils were inserted into the annular channel to monitor the cellular structure of the detonation wave. The results show that, well within the detonability limits, the detonation wave propagates along the channel with a small local velocity fluctuation and an average global velocity can be deduced. The average detonation velocity has a small deficit of 5-15 % far from the limits and the velocity rapidly decreases to 0.7V_{CJ}-0.8V_{CJ} when the detonation propagates near the limit. Subsequently, the fluctuation of local velocity also increases as the decreasing initial pressure approaches the limit. In the two annular channels used in this work, no galloping detonations were observed for both the stable and unstable mixtures tested. The present study also confirms that single-headed spinning detonation occurs at the limit, as in a circular tube, rather than the up and down "zig zag" mode in a two-dimensional, rectangular channel.

  20. Development and qualification testing of a laser-ignited, all-secondary (DDT) detonator

    Science.gov (United States)

    Blachowski, Thomas J.; Krivitsky, Darrin Z.; Tipton, Stephen

    1994-01-01

    The Indian Head Division, Naval Surface Warfare Center (IHDIV, NSWC) is conducting a qualification program for a laser-ignited, all-secondary (DDT) explosive detonator. This detonator was developed jointly by IHDIV, NSWC and the Department of Energy's EG&G Mound Applied Technologies facility in Miamisburg, Ohio to accept a laser initiation signal and produce a fully developed shock wave output. The detonator performance requirements were established by the on-going IHDIV, NSWC Laser Initiated Transfer Energy Subsystem (LITES) advanced development program. Qualification of the detonator as a component utilizing existing military specifications is the selected approach for this program. The detonator is a deflagration-to-detonator transfer (DDT) device using a secondary explosive, HMX, to generate the required shock wave output. The prototype development and initial system integration tests for the LITES and for the detonator were reported at the 1992 International Pyrotechnics Society Symposium and at the 1992 Survival and Flight Equipment National Symposium. Recent results are presented for the all-fire sensitivity and qualification tests conducted at two different laser initiation pulses.

  1. Simulation of detonation of ammonium nitrate fuel oil mixture confined by aluminum: edge angles for DSD

    Energy Technology Data Exchange (ETDEWEB)

    Short, Mark [Los Alamos National Laboratory; Quirk, James J [Los Alamos National Laboratory; Kiyanda, Charles B [Los Alamos National Laboratory; Jackson, Scott I [Los Alamos National Laboratory; Briggs, Matthew E [Los Alamos National Laboratory; Shinas, Micheal A [Los Alamos National Laboratory

    2010-01-01

    Non-ideal high explosives are typically porous, low-density materials with a low detonation velocity (3--5 km/s) and long detonation reaction zone ({approx} cms). As a result, the interaction of a non-ideal high explosive with an inert confiner can be markedly different than for a conventional high explosive. Issues arise, for example, with light stiff confiners where the confiner can drive the high explosive (HE) through a Prandtl-Meyer fan at the HE/confiner interface rather than the HE driving the confiner. For a non-ideal high explosive confined by a high sound speed inert such that the detonation velocity is lower than the inert sound speed, the flow is subsonic and thus shockless in the confiner. In such cases, the standard detonation shock dynamics methodology, which requires a positive edge-angle be specified at the HE/confiner interface in order that the detonation shape be divergent, cannot be directly utilized. In order to study how detonation shock dynamics can be utilized in such cases, numerical simulations of the detonation of ammonium nitrate-fuel oil (ANFO) confined by aluminum 6061 are conducted.

  2. On the neutralization of bacterial spores in post-detonation flows

    Science.gov (United States)

    Gottiparthi, K. C.; Schulz, J. C.; Menon, S.

    2014-09-01

    In multiple operational scenarios, explosive charges are used to neutralize confined or unconfined stores of bacterial spores. The spore destruction is achieved by post-detonation combustion and mixing of hot detonation product gases with the ambient flow and spore clouds. In this work, blast wave interaction with bacterial spore clouds and the effect of post-detonation combustion on spore neutralization are investigated using numerical simulations. Spherical explosive charges (radius, = 5.9 cm) comprising of nitromethane are modeled in the vicinity of a spore cloud, and the spore kill in the post-detonation flow is quantified. The effect of the mass of the spores and the initial distance, , of the spore cloud from the explosive charge on the percentage of spores neutralized is investigated. When the spores are initially placed within a distance of 3.0, within 0.1 ms after detonation of the charge, all the spores are neutralized by the blast wave and the hot detonation product gases. In contrast, almost all the spores survived the explosion when is greater than 8.0. The percentage of intact spores varied from 0 to 100 for 3.0 8.0 with spore neutralization dependent on time spent by the spores in the post-detonation mixing/combustion zone.

  3. A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

    Science.gov (United States)

    Garg, Uma; Chang, Philip

    2017-02-01

    Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneous wave speed and the Chapman–Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon–oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.

  4. Asymmetry and the Nucleosynthetic Signature of Nearly Edge-Lit Detonation in White Dwarf Cores

    CERN Document Server

    Chamulak, David A; Seitenzahl, Ivo R; Truran, James W

    2011-01-01

    Most of the leading explosion scenarios for Type Ia supernovae involve the nuclear incineration of a white dwarf star through a detonation wave. Several scenarios have been proposed as to how this detonation may actually occur, but the exact mechanism and environment in which it takes place remain unknown. We explore the effects of an off-center initiated detonation on the spatial distribution of the nucleosynthetic yield products in a toy model - a pre-expanded near Chandrasekhar-mass white dwarf. We find that a single near edge-lit detonation results in asymmetries in the density and thermal profiles, notably the expansion timescale, throughout the supernova. We demonstrate that this asymmetry of the thermodynamic trajectories should be common to off-center detonations where a small amount of the star is burned prior to detonation. The asymmetry stems from the fact that in one hemisphere the propagation direction of the detonation wave is largely in the direction of final (radial) expansion, whereas in the ...

  5. Unsteady self-sustained detonation waves in flake aluminum dust/air mixtures

    CERN Document Server

    Liu, Qingming; Zhang, Yunming; Li, Shuzhuan

    2015-01-01

    Self-sustained detonation waves in flake aluminum dust/air mixtures have been studied in a tube of diameter 199 mm and length 32.4 m. A pressure sensor array of 32 sensors mounted around certain circumferences of the tube was used to measure the shape of the detonation front in the circumferential direction and pressure histories of the detonation wave. A two-head spin detonation wave front was observed for the aluminum dust/air mixtures, and the cellular structure resulting from the spinning movement of the triple point was analyzed. The variations in velocity and overpressure of the detonation wave with propagation distance in a cell were studied. The interactions of waves in triple-point configurations were analyzed and the flow-field parameters were calculated. Three types of triple-point configuration exist in the wave front of the detonation wave of an aluminum dust/air mixture. Both strong and weak transverse waves exist in the unstable self-sustained detonation wave.

  6. Ignition and growth modeling of detonation reaction zone experiments on single crystals of PETN and HMX

    Science.gov (United States)

    White, Bradley W.; Tarver, Craig M.

    2017-01-01

    It has long been known that detonating single crystals of solid explosives have much larger failure diameters than those of heterogeneous charges of the same explosive pressed or cast to 98 - 99% theoretical maximum density (TMD). In 1957, Holland et al. demonstrated that PETN single crystals have failure diameters of about 8 mm, whereas heterogeneous PETN charges have failure diameters of less than 0.5 mm. Recently, Fedorov et al. quantitatively determined nanosecond time resolved detonation reaction zone profiles of single crystals of PETN and HMX by measuring the interface particle velocity histories of the detonating crystals and LiF windows using a PDV system. The measured reaction zone time durations for PETN and HMX single crystal detonations were approximately 100 and 260 nanoseconds, respectively. These experiments provided the necessary data to develop Ignition and Growth (I&G) reactive flow model parameters for the single crystal detonation reaction zones. Using these parameters, the calculated unconfined failure diameter of a PETN single crystal was 7.5 +/- 0.5 mm, close to the 8 mm experimental value. The calculated failure diameter of an unconfined HMX single crystal was 15 +/- 1 mm. The unconfined failure diameter of an HMX single crystal has not yet been determined precisely, but Fedorov et al. detonated 14 mm diameter crystals confined by detonating a HMX-based plastic bonded explosive (PBX) without initially overdriving the HMX crystals.

  7. Deflagration-to-detonation transition project: quarterly report for the period September through November 1979

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, M. L. [ed.

    1980-07-01

    The activities of the Sandia Laboratories project on deflagration-to-detonation transition (DDT) pertain primarily to the development of small, safe, low-voltage, hot-wire detonators. Its major goals are: the formulation of a modeling capability for DDT of the explosive 2-(5-cyanotetrazolato)pentaamminecobalt(III) perchlorate (CP); the development of improved DDT materials; the establishment of a data base for corrosion, compatibility, and reliability of CP-loaded detonators; and the design and development of advanced DDT components. Progress in this research is reported. The planned development of the MC3423 detonator has been completed and the final design review meeting has been held. Additional work must be performed to establish satisfactory output function. Ignition sensitivity data have also been obtained. Ignition and shock testing experiments for development of the MC3533 detonator have been planned. An initial version of the component will utilize available MC3423 headers, while the final design will incorporate a new header that has been designed and ordered. Detonator performance studies have been planned to optimize CP density-length factors. Feasibility studies on the MC3196A detonator have continued in an effort to obtain a reliable 50-200 ..mu..s function time.

  8. The propagation of detonation waves in non-ideal condensed-phase explosives confined by high sound-speed materials

    Science.gov (United States)

    Schoch, Stefan; Nikiforakis, Nikolaos; Lee, Bok Jik

    2013-08-01

    Highly non-ideal condensed-phase explosives used by the mining industry have a strong detonation velocity dependence on the charge dimension. Detonation velocities can be as low as one third of the theoretically calculated ideal detonation velocity in charge radii close to the failure radius. Under these detonation conditions the flow in the confiner can become subsonic, a flow condition under which classical shock-polar analysis is not applicable. This restriction prohibits the use of popular engineering models like detonation shock dynamics and Wood-Kirkwood type models under these confinement conditions. In addition, it has been found in the literature that subsonic flow in the confiner will increase the influence of the confining material on the detonation performance. In this work, we use a multi-phase model coupled to an elastic-plastic model (for the representation of a confiner) to explore the interaction of detonations under these confiner conditions. An ammonium nitrate based mining emulsion is investigated in aluminium and steel confinement of finite and infinite thickness representing the confiner as either a fluid or an elastic-plastic material. It is found that the presence of elastic waves is negligible close to ideal detonation conditions, but is important close to the failure radius and in detonation conditions with subsonic flow in the confiner. High sound-speed confiners support the detonation through energy transport ahead of the detonation front if desensitisation effects are negligible. The detonation front profiles are found to remain convex even in the most non-ideal detonation conditions, and the detonation front curvature only becomes concave in a localised region close to the confiner edge.

  9. Spatial contrast sensitivity in benign intracranial hypertension.

    Science.gov (United States)

    Bulens, C; Meerwaldt, J D; Koudstaal, P J; Van der Wildt, G J

    1988-01-01

    Spatial Contrast Sensitivity (CS) was studied in 20 patients with benign intracranial hypertension (BIH). At presentation CS loss was found in 43% of the eyes, and impairment of visual acuity attributed to BIH in only 16%. Nine patients had blurred vision or visual obscurations, all of whom had abnormal CS. The clinical application of CS measurement in BIH for monitoring the progression or regression of the disease is illustrated by serial measurements in 11 patients. Progressive visual loss in longstanding papilloedema and improvement of visual function in subsiding papilloedema can occur without any change in Snellen acuity or visual field charting. PMID:3225588

  10. Spatial contrast sensitivity in benign intracranial hypertension.

    Science.gov (United States)

    Bulens, C; Meerwaldt, J D; Koudstaal, P J; Van der Wildt, G J

    1988-10-01

    Spatial Contrast Sensitivity (CS) was studied in 20 patients with benign intracranial hypertension (BIH). At presentation CS loss was found in 43% of the eyes, and impairment of visual acuity attributed to BIH in only 16%. Nine patients had blurred vision or visual obscurations, all of whom had abnormal CS. The clinical application of CS measurement in BIH for monitoring the progression or regression of the disease is illustrated by serial measurements in 11 patients. Progressive visual loss in longstanding papilloedema and improvement of visual function in subsiding papilloedema can occur without any change in Snellen acuity or visual field charting.

  11. Benign symmetric lipomatosis of the knees

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Yin; Di Wu; Yixin Ge; Meihua Zhang; Zhigang Bi; Dan Luo

    2008-01-01

    Benign symmetric lipomatosis(BSL) is a rare disease characterized by the presence of multiple, symmetric and nonencapsulated fat masses in the face, neck and other areas. It is commonly seen in middle-aged Caucasian Mediterranean males, while its etiology is still not clear. The majority of the patients with BSL have a history of alcohol abuse and hepatopathy. BSL of the limbs is very rare. This article reports a unique case of a 60-year-old Chinese woman with involvement of the knees confirmed by the results of magnetic resonance imaging(MRI) and histopathology, which was not described previously in published literatures.

  12. Clarithromycin Culprit of Benign Intracranial Hypertension

    Directory of Open Access Journals (Sweden)

    Habib Rehman Khan

    2015-01-01

    Full Text Available Benign intracranial hypertension is characterized with increase in CSF opening pressure with no specific etiology. It is predominantly found in women of child bearing age and particularly in individuals with obesity. Visual disturbances or loss and associated headaches are common and can lead to blindness if left untreated. Diagnosis can be achieved once other causes of visual loss, headaches and high opening pressures are excluded. Management consists of serial optic disc assessments although no specific treatment is available despite recent trials using carbonic anhydrase inhibitors. Diet modification and weight management can help in therapy.

  13. Study on mechanism of sheer thickening fluiding enhancing stab-risistant performance of fabric%剪切增稠液体增强织物防刺性能的机理研究

    Institute of Scientific and Technical Information of China (English)

    徐素鹏; 郑伟; 张玉芳

    2012-01-01

    Shear thickening fluids (STF) with mass fraction of 20% and 26% were prepared, and its rheology behavior, the stab-resistant performance of UHMWPE fabric impregnated with STF and the mechanism of STF enhanceing fabric's stab-resistant performance are studied. The results show that two kinds of fluid have rheological behavior which firstly shear thinning and then shear thickening; because STF can passivate the tools and limit yarns and fiber's moving, stab-resistant performance of UHMWPE fabric is enhanced obviously by STF; the stab-resistant performance of STF/UHMWPE non-woven fabric composite materials is better than STF/UHMWPE woven fabric composite materials; and with increasing solids content of STF, the effects of STF enhancing UHMWPE fabric's stab-resistant performance are more significant; the stab-resistant performance of STF/UHMWPE composite materials and pure UHMWPE plying compundly is better than plying individually, and composite materials plied upper are better.%制备出质量分数分别为20%和26%的剪切增稠液体(STF),研究了其流变性能、浸渍UHMWPE织物后所得的复合材料在不同条件下的防刺性能和STF增强织物防刺性能的机理.结果表明:2种液体均具有先剪切变稀后剪切增稠的流变性能曲线;由于STF具有钝化刀具和限制织物纱线或纤维移动的作用,能明显增强UHMWPE织物的防刺性能;STF/UHMWPE无纺布复合材料的防刺性能优于STF/UHMWPE机织布复合材料;随着STF固含量的增大,STF增强织物防刺性能的效果更加显著;STF/UHMWPE复合材料与纯UHMWPE复合铺层的防刺性能优于STF/UHMWPE复合材料单独铺层时的防刺性能,而且STF/UHMWPE复合材料放在最上层效果较好.

  14. Simulation of Gas Detonation Propagation in a Medium Having Variable Chemical Composition

    Science.gov (United States)

    Prokhorov, E. S.

    2017-01-01

    Within the framework of a quasi-one-dimensional approximation, a mathematical model of the propagation of a detonation wave in a tube filled with explosive gas mixture with spatially variable chemical composition has been formulated, and the respective problem has been solved numerically. The shift in the chemical equilibrium of detonation products as well as the friction and heat removal losses were taken into account. The proposed mathematical model allows one to describe steady-state (of Chapman-Jouguet) and over-compressed detonation regimes.

  15. Computer Modeling of a Rotating Detonation Engine in a Rocket Configuration

    Science.gov (United States)

    2015-03-01

    coefficient CP Specific heat capacity at constant pressure ( J kg−K ) CS Nozzle stream thrust coefficient D Detonation wave speed in laboratory frame-of...greater than the detonation fuel-to-air ratio, the ratio of specific heats and gas constant at station c3.4 are calculated using Eq. 75 and Eq. 76...COMPUTER MODELING OF A ROTATING DETONATION ENGINE IN A ROCKET CONFIGURATION THESIS Nihar N. Shah, 1st Lt, USAF AFIT-ENY-MS-15-M-230 DEPARTMENT OF THE

  16. Analysis of trapped gas in 1E34 detonators by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Warner, D.K.; Back, P.S.; Barnhart, B.V.

    1980-05-14

    A method was developed to extract and then analyze gas trapped in thermally aged 1E34 detonators. This gas was extracted into an evacuated volume and injected into a gas chromatograph for separation and quantitative analysis. To effect this gas extraction, a device was designed for puncturing the detonator cup and capturing the effused gas. Limited testing of five detonators in this device shows amounts of gas ranging from about 0.5 X 10 {sup -7} to 12 X 10 {sup - 7} moles.

  17. MC3644 detonator development status report for the period ending October 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, A.K.

    1982-01-01

    The MC3644 detonator is being developed as a replacement for the MC3132 flying plate detonator in the parachute deployment system of the B83 weapon. The MC3644 is a CP, deflagration-to-detonation transition device. Two models are being developed: an interim design using the MC3423 ignitor and a new production version with a one-piece ignitor/header assembly. Features of both designs are described. Results of development tests involving the interim design are presented. No-fire sensitivity test and proof-test results with the WR version are also included. The development program is on schedule.

  18. Histiocytic sarcoma that mimics benign histiocytosis.

    Science.gov (United States)

    Boisseau-Garsaud, A M; Vergier, B; Beylot-Barry, M; Nastasel-Menini, F; Dubus, P; de Mascarel, A; Eghbali, H; Beylot, C

    1996-06-01

    A 28-year-old man presented with a histiocytic sarcoma of a very uncommon origin, as it had developed for several years like a benign cutaneous histiocytosis resembling generalized eruptive histiocytoma before becoming acute, with nodal and massive pulmonary involvement. Despite various chemotherapies, the patient died within 8 months. Skin biopsies showed histiocytic proliferation in the dermis and node biopsies showed histiocytic proliferation with a sinusoidal pattern. Immunohistochemical analysis, performed on paraffin-embedded sections, demonstrated strong labeling of tumoral cells for CD68 and moderate labeling for CD3 and CD4. CD30 labeling was negative. S-100 protein was positive on a Langerhans' cell reactive subpopulation. Electron microscopy confirmed the histiocytic nature of malignant cells and showed cytoplasmic inclusions such as regularly laminated bodies, dense bodies and pleomorphic inclusions. No Birbeck granules were seen. A gene rearrangement study of T-cell receptor gamma and immunoglobulin heavy chain genes showed a germline configuration. Histiocytic sarcoma is an extremely rare true histiocytic malignancy, the existence of which has been recently debated since it has often been mistaken in the past for large cell lymphomas. Such a deceptive onset as benign cutaneous histiocytosis has not been described in the literature to our knowledge.

  19. Benign cementoblastoma (true cementoma in a cat

    Directory of Open Access Journals (Sweden)

    Lenin A Villamizar-Martinez

    2016-01-01

    Full Text Available Case summary A 10-year-old castrated male domestic shorthair cat was presented for assessment of a gingival mass surrounding the left maxillary third and fourth premolar teeth. The mass was surgically removed by means of a marginal rim excision, and the tissue was submitted for histological assessment. It was identified as a benign cementoblastoma (true cementoma. There was proliferation of mineralized eosinophilic material with multiple irregularly placed lacunae and reversal lines, reminiscent of cementum. The cat recovered uneventfully from the anesthesia, and there was no evidence of tumor recurrence 6 months after surgery. Relevance and novel information Cementoblastomas (true cementomas in domestic animals are rare, with just a few reports in ruminants, monogastric herbivores and rodents. Cementoblastoma is considered a benign tumor that arises from the tooth root. The slow, expansive and constant growth that characterizes these masses may be accompanied by signs of oral discomfort and dysphagia. This case report is intended to increase knowledge regarding this tumor in cats and also highlights the importance of complete excision of the neoplasm. To our knowledge, there are no previous reports in the literature of cementoblastoma in the cat.

  20. Reduction of global effects on vehicles after IED detonations

    Institute of Scientific and Technical Information of China (English)

    V.DENEFELD; N.HEIDER; A.HOLZWARTH; A.S€ATTLER; M.SALK

    2014-01-01

    Global effects caused by the detonation of an IED near a military vehicle induce subsequent severe acceleration effects on the vehicle occupants. Two concepts to minimize these global effects were developed, with the help of a combined method based on a scaled experimental technology and numerical simulations. The first concept consists in the optimization of the vehicle shape to reduce the momentum transfer and thus the occupant loading. Three scaled V-shaped vehicles with different ground clearances were built and compared to a reference vehicle equipped with a flat floor. The second concept, called dynamic impulse compensation (DIC), is based on a momentum compensation technique. The principal possibility of this concept was demonstrated on a scaled vehicle. In addition, the numerical simulations have been performed with generic full size vehicles including dummy models, proving the capability of the DIC technology to reduce the occupant loading.

  1. Spontaneous Transition of Turbulent Flames to Detonations in Unconfined Media

    CERN Document Server

    Poludnenko, Alexei Y; Oran, Elaine S

    2011-01-01

    Deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems to astrophysical thermonuclear (type Ia) supernovae explosions. Substantial progress has been made in explaining the nature of DDT in confined systems with walls, internal obstacles, or pre-existing shocks. It remains unclear, however, whether DDT can occur in unconfined media. Here we use direct numerical simulations (DNS) to show that for high enough turbulent intensities unconfined, subsonic, premixed, turbulent flames are inherently unstable to DDT. The associated mechanism, based on the nonsteady evolution of flames faster than the Chapman-Jouguet deflagrations, is qualitatively different from the traditionally suggested spontaneous reaction wave model, and thus does not require the formation of distributed flames. Critical turbulent flame speeds, predicted by this mechanism for the onset of DDT, are in agreement with DNS results.

  2. Influence of thermal oxidation on as-synthesized detonation nanodiamond

    Institute of Scientific and Technical Information of China (English)

    Xiangyang Xu; Zhiming Yu

    2012-01-01

    The thermal property of an as-synthesized black powder,a detonation nanodiamond (DND) product,was first analyzed,followed by thermal oxidation to modify its surface.During the thermal treatment,the non-diamond carbonaceous shell of the black powder was oxidized,with the likelihood of forming a C-O-C bonding between carbon atoms on the particle surface.This new structure may rupture with intensified oxidation through increasing the heating temperature and prolonging the process duration.As more oxygen-containing functional groups form on the particle surface,the particle surface becomes negatively charged,and the powder turns to be more hydrophilic.

  3. Low-cost optoelectronic devices to measure velocity of detonation

    Science.gov (United States)

    Chan, Edwin M.; Lee, Vivian; Mickan, Samuel P.; Davies, Phil J.

    2005-02-01

    Velocity of Detonation (VoD) is an important measured characteristic parameter of explosive materials. When new explosives are developed, their VoD must be determined. Devices used to measure VoD are always destroyed in the process, however replacing these devices represents a considerable cost in the characterisation of new explosives. This paper reports the design and performance of three low-cost implementations of a point-to-point VoD measurement system, two using optical fibre and a third using piezoelectric polymers (PolyVinyliDine Flouride, PVDF). The devices were designed for short charges used under controlled laboratory conditions and were tested using the common explosive 'Composition B'. These new devices are a fraction of the cost of currently available VoD sensors and show promise in achieving comparable accuracy. Their future development will dramatically reduce the cost of testing and aid the characterisation of new explosives.

  4. A theoretical equation of state for detonation products

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, M.S.

    1998-12-31

    A theoretical equation of state for detonation products is described that places particular emphasis on the characterization of small carbon clusters (20{angstrom}--50{angstrom} in diameter) in the products. Diamond clusters are modeled with the dangling bonds on the surface atoms (up to 30% of the cluster) capped by various radicals composed of C, H, N, and O from the background molecular fluid mixture. Free energy methods for the surface groups are used to determine the chemical equilibrium composition of the cluster surface as well as the surrounding molecular fluid mixture. The surface composition shows dramatic changes in composition over some regions and varies slowly in others. A perturbation theory approach is used for the mixture of molecular fluids that also includes features based on Monte Carlo simulations.

  5. Volume Ignition via Time-like Detonation in Pellet Fusion

    CERN Document Server

    Csernai, L P

    2015-01-01

    Relativistic fluid dynamics and the theory of relativistic detonation fronts are used to estimate the space-time dynamics of the burning of the D-T fuel in Laser driven pellet fusion experiments. The initial "High foot" heating of the fuel makes the compressed target transparent to radiation, and then a rapid ignition pulse can penetrate and heat up the whole target to supercritical temperatures in a short time, so that most of the interior of the target ignites almost simultaneously and instabilities will have no time to develop. In these relativistic, radiation dominated processes both the interior, time-like burning front and the surrounding space-like part of the front will be stable against Rayleigh-Taylor instabilities. To achieve this rapid, volume ignition the pulse heating up the target to supercritical temperature should provide the required energy in less than ~ 10 ps.

  6. Physicochemical model of detonation synthesis of nanoparticles from metal carboxylates

    Science.gov (United States)

    Tolochko, B. P.; Chernyshev, A. P.; Ten, K. A.; Pruuel, E. R.; Zhogin, I. L.; Zubkov, P. I.; Lyakhov, N. Z.; Luk'yanchikov, L. A.; Sheromov, M. A.

    2008-02-01

    We have shown previously that when metal carboxylates are subjected to a shock-wave action, diamond nanoparticles and nanoparticles of metals (Ag, Bi, Co, Fe, Pb) are formed and their characteristic size is about 30-200 Å. The metal nanoparticles formed are covered by an amorphous-carbon layer up to 20 Å thick. In this work we put forward a physicochemical model of the formation of diamond and metal nanoparticles from metal carboxylates upon shock-wave action. The energy released upon detonation inside the precursor is lower than in regions not occupied by the stearates. The characteristic time of temperature equalization has been estimated to be on the order of ˜10-3 s, which is greater by a factor of ˜103 than the characteristic reaction time. Due to the adiabatic nature of the processes occurring, the typical temperature of a "particle" will be lower than the temperature of the surrounding medium. In the framework of the model suggested, it has been assumed that the growth of metal clusters should occur by the diffusion mechanism; i.e., the "building material" is supplied through diffusion. The calculation using our previous experimental data on the reaction time and average size of metal particles has shown that the diffusion properties of the medium in which the metal nanoparticles are formed are close to those of the liquid state of the substance. The temperature and pressure under detonation conditions markedly exceed the analogous parameters characteristic of experiments on the thermodestruction of metal carboxylates. The small time of existence of the reaction mixture is compensated by the high mobility and concentration of reagents.

  7. Axisymmetric Numerical Modeling of Pulse Detonation Rocket Engines

    Science.gov (United States)

    Morris, Christopher I.

    2005-01-01

    Pulse detonation rocket engines (PDREs) have generated research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional rocket engines. The detonative mode of combustion employed by these devices offers a thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional rocket engines and gas turbines. However, while this theoretical advantage has spurred considerable interest in building PDRE devices, the unsteady blowdown process intrinsic to the PDRE has made realistic estimates of the actual propulsive performance 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. In recent work by the author, a quasi-one-dimensional, finite rate chemistry CFD model was utilized to study the gasdynamics and performance characteristics of PDREs over a range of blowdown pressure ratios from 1-1000. Models of this type are computationally inexpensive, and enable first-order parametric studies of the effect of several nozzle and extension geometries on PDRE performance over a wide range of conditions. However, the quasi-one-dimensional approach is limited in that it cannot properly capture the multidimensional blast wave and flow expansion downstream of the PDRE, nor can it resolve nozzle flow separation if present. Moreover, the previous work was limited to single-pulse calculations. In this paper, an axisymmetric finite rate chemistry model is described and utilized to study these issues in greater detail. Example Mach number contour plots showing the multidimensional blast wave and nozzle exhaust plume are shown. The performance results are compared with the quasi-one-dimensional results from the previous paper. Both Euler and Navier-Stokes solutions are calculated in order to determine the effect of viscous

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

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Aleman, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    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.

  9. Benign and malignant tumors of the foot and ankle

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Adam D.; Datir, Abhijit; Langley, Travis [Emory University Hospital, Department of Radiology, Section of Musculoskeletal Imaging, Atlanta, GA (United States); Tresley, Jonathan [University of Wisconsin, Department of Radiology, Madison, WI (United States); Clifford, Paul D.; Jose, Jean; Subhawong, Ty K. [University of Miami, Department of Radiology, Miami, FL (United States)

    2016-03-15

    Pain and focal masses in the foot and ankle are frequently encountered and often initiate a workup including imaging. It is important to differentiate benign lesions from aggressive benign or malignant lesions. In this review, multiple examples of osseous and soft tissue tumors of the foot and ankle will be presented. Additionally, the compartmental anatomy of the foot and ankle will be discussed in terms of its relevance for percutaneous biopsy planning and eventual surgery. Finally, a general overview of the surgical management of benign, benign aggressive and malignant tumors of the foot and ankle will be discussed. (orig.)

  10. The appendix: a spectrum of benign and malignant disease.

    Science.gov (United States)

    Lord, Christopher; Broadhurst, Jack; Sleight, Simon; McGee, Shaun; Wills, Mark

    2017-02-02

    This article discusses the radiological appearances and subsequent management of a diverse spectrum of benign and malignant appendiceal pathologies, including those masquerading as acute appendicitis.

  11. Clustered microcalcifications without mass on mammography : benignancy vs. malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yoon Hee; Do, Young Soo; Oh, Hoon Il; Kim, Ki Hwan; Chin, Soo Yil [Korean Cancer Center Hostpital, Seoul (Korea, Republic of); Cho, Byung Jae [Chung Dam Radiologic Clinics, Seoul (Korea, Republic of); Han, Heon [Chungang Gil Hospital, Seoul (Korea, Republic of); Choi, Yeun Hyeun; Han, Boo Kyung [Sam Sung Medical Center, Seoul (Korea, Republic of); Park, Jung Mi [Asan Medical Center, Seoul (Korea, Republic of)

    1996-11-01

    The purpose of this study is to evaluate the accuracy of differentiation between benign and malignant clustered microcalcifications without mass on mammogram. Fourty six mammograms of 44 patients showing clustered microcalcifications without mass were interpreted blindly by five independent observers majoring in breast imaging from different institutions. Twenty two were malignant (10 infiltrating ductal carcinomas, 12 intraductal carcinomas) and 24 were benign (all fibrocystic disease). The observers judge benignancy or malignancy of microcalcifications. The authors assess the accuracy of differential diagnosis of clustered microcalcifications. Of 24 cases proved benign microcalcifications, five radiologists correctly interpreted 20 on average as benign and of malignant 22 cases, 16 on average were correctly interpreted as malignant. The diagnostic accuracy of malignant microcalcifications was 71.8% on average(63.6%{approx}81.8%) and the diagnostic accuracy for benign microcalcifications was 83% on average(71%{approx}92%). It was 9 among total 46 cases that were misinterpreted by more than three radiologists. Among these 9 cases, malignant microcalcifications that had been misinterpreted as benign were seven, benign microcalcifications misinterpreted as malignant were two. The diagnostic accuracy of clustered malignant microcalcifications(71.8%) without mass on mammogram was lower than that of benign microcalcifications(83.3%). So, in case of suspected malignant microcalcification on mammogram, it is preferable that along with magnification view, histopathologic confirmation by core biopsy must be obtained.

  12. Multiplicity of detonation regimes in systems with a multi-peaked thermicity

    CERN Document Server

    Lau-Chapdelaine, S SM; Zhang, F; Radulescu, M I

    2015-01-01

    The study investigates detonations with multiple quasi-steady velocities that have been observed in the past in systems with multi-peaked thermicity, using Fickett's detonation analogue. A steady state analysis of the travelling wave predicts multiple states, however, all but the one with the highest velocity develop a singularity after the sonic point. Simulations show singularities are associated with a shock wave which overtakes all sonic points, establishing a detonation travelling the highest of the predicted velocities. Under a certain parameter range, the steady-state detonation can have multiple sonic points and solutions. Embedded shocks can exist behind sonic points, where they link the weak and strong solutions. Sonic points whose characteristics do not diverge are found to be unstable, and to be the source of the embedded shocks. Numerical simulations show that these shocks are only quasi stable. This is believed to be due to the reaction rates having been chosen to be independent of hydrodynamics...

  13. OGLE-2013-SN-079: A LONELY SUPERNOVA CONSISTENT WITH A HELIUM SHELL DETONATION

    Energy Technology Data Exchange (ETDEWEB)

    Inserra, C.; Sim, S. A.; Smartt, S. J.; Nicholl, M.; Jerkstrand, A.; Chen, T.-W. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Wyrzykowski, L. [University of Warsaw, Astronomical Observatory, Al. Ujazdowskie 400-478 Warszawa (Poland); Fraser, M.; Blagorodnova, N.; Campbell, H. [Institute of Astronomy, University of Cambridge, Madingley Road, CB3 0HA Cambridge (United Kingdom); Shen, K. J. [Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); Gal-Yam, A. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Howell, D. A.; Valenti, S. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102 Goleta, CA 93117 (United States); Maguire, K. [European Southern Observatory for Astronomical Research in the Southern Hemisphere (ESO), Karl-Schwarzschild-Str. 2, 85748 Garching b. Munchen (Germany); Mazzali, P.; Bersier, D. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool (United Kingdom); Taubenberger, S.; Benitez-Herrera, S. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany); Elias-Rosa, N., E-mail: c.inserra@qub.ac.uk [INAF - Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); and others

    2015-01-20

    We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of z = 0.07 implies an absolute magnitude in the rest-frame I-band of M{sub I} ∼ –17.6 mag. This places it in the luminosity range between normal Type Ia SNe and novae. Optical and near infrared spectroscopy reveal mostly Ti and Ca lines, and an unusually red color arising from strong depression of flux at rest wavelengths <5000 Å. To date, this is the only reported SN showing Ti-dominated spectra. The data are broadly consistent with existing models for the pure detonation of a helium shell around a low-mass CO white dwarf and ''double-detonation'' models that include a secondary detonation of a CO core following a primary detonation in an overlying helium shell.

  14. Microscopic simulations of supersonic and subsonic exothermic chemical wave fronts and transition to detonation

    Science.gov (United States)

    Lemarchand, A.; Nowakowski, B.; Dumazer, G.; Antoine, C.

    2011-01-01

    We perform microscopic simulations using the direct simulation Monte Carlo approach to an exothermic chemical wave front of Fisher-Kolmogorov, Petrovsky, Piskunov-type in a one-dimensional gaseous medium. The results confirm the existence of a transition from a weak detonation or deflagration to a Chapman-Jouguet detonation wave, that we already investigated at the macroscopic scale [G. Dumazer et al., Phys. Rev. E 78, 016309 (2008)]. In the domain of weak detonation or deflagration, the discrepancy between the propagation speeds deduced from the simulations and the macroscopic balance equations of hydrodynamics is explained by two microscopic effects, the discretization of the variables, known as cutoff effect, and the departure from local equilibrium. Remarkably, the propagation speed of a Chapman-Jouguet detonation wave is not sensitive to these perturbations of microscopic origin.

  15. Detonation Nanodiamond Toxicity in Human Airway Epithelial Cells Is Modulated by Air Oxidation

    Science.gov (United States)

    Detonational nanodiamonds (DND), a nanomaterial with an increasing range of industrial and biomedical applications, have previously been shown to induce a pro-inflammatory response in cultured human airway epithelial cells (HAEC). We now show that surface modifications induced by...

  16. Velocity of detonation at any initial density without using heat of formation of explosives.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Alamdari, Reza Fareghi; Moghadas, Mohammad Hassan; Mostofizadeh, Ali Reza; Sadeghi, Hossein

    2006-10-11

    The simplest method is introduced for reliable estimating the detonation velocity of large class of CHNO explosives based elemental composition and specific structural groups. There is no need to use heat of formation and the other experimental data for calculation of detonation velocity in the new procedure. Only elemental composition and the number of special structural groups without using heat of formation of explosive is sufficient for reliable desk calculation of detonation velocity. The results show good agreement with experimental values with respect to computed results obtained by complex computer code using BKWS and BKWR equations of state. Predicted velocities of detonation have root-mean-square (rms) percent deviation of 2.2, 5.9 and 5.3 from experimental data for new method, BKWS and BKWR equations of state, respectively.

  17. Prediction of detonation performance of CHNO and CHNOAl explosives through molecular structure.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2009-07-30

    A new pathway has been introduced to predict detonation pressure of CHNO and CHNOAl explosives. Although aluminized explosives can have Chapman-Jouguet detonation performance significantly different from those expected from existing thermodynamic computer codes for equilibrium and steady state calculations, new correlation can also be used here. Molecular structures of CHNO and CHNOAl explosives are the only necessary parameters that would be needed in this new scheme. There is no need to use heat of formation or any experimental data. Besides, elemental compositions of CHNO and CHNOAl explosives rather than assumed detonation products are essential input parameters. Predicted detonation pressures for CHNO explosives are compared with experimental data as well as computed results gained by complicated computer code using BKWR and BKWS equations of state so the new method shows the best results. Also, the calculated results for CHNOAl explosives indicate good agreement with the measured data as compared to estimated results of BKWS-EOS using full and partial equilibrium.

  18. Confined detonations with cylindrical and spherical symmetry; Detonaciones confinadas con simetria esferica y cilindrica

    Energy Technology Data Exchange (ETDEWEB)

    Linan, A.; Lecuona, A.

    1979-07-01

    An imploding spherical or cylindrical detonation, starting in the interface of the detonantion with an external inert media, used as a reflector, creates on it a strong shock wave moving outward from the interface. An initially weak shock wave appears in the detonated media that travels toward the center, and it could reach the detonation wave, enforcing it in its process of implosion. To describe the fluid field, the Euler s equations are solved by means of expansions valid for the early stages of the process. Isentropic of the type P/p{gamma}-K for the detonated and compressed inert media are used. For liquid or solid reflectors a more appropriate equation is used. (Author) 8 refs.

  19. Modeling the mechanics of HMX detonation using a Taylor–Galerkin scheme

    Directory of Open Access Journals (Sweden)

    Adam V. Duran

    2016-05-01

    Full Text Available Design of energetic materials is an exciting area in mechanics and materials science. Energetic composite materials are used as propellants, explosives, and fuel cell components. Energy release in these materials are accompanied by extreme events: shock waves travel at typical speeds of several thousand meters per second and the peak pressures can reach hundreds of gigapascals. In this paper, we develop a reactive dynamics code for modeling detonation wave features in one such material. The key contribution in this paper is an integrated algorithm to incorporate equations of state, Arrhenius kinetics, and mixing rules for particle detonation in a Taylor–Galerkin finite element simulation. We show that the scheme captures the distinct features of detonation waves, and the detonation velocity compares well with experiments reported in literature.

  20. A report on the deflagration-to-detonation transition (DDT) in the high explosive LX-04

    Energy Technology Data Exchange (ETDEWEB)

    Hare, D E; Forbes, J W; Garcia, F; Granholm, R H; Tarver, C M; Vandersall, K S; Sandusky, H W

    2004-06-30

    The deflagration-to-detonation transition (DDT) was investigated for 1.874 g/cc (98.8 % of theoretical maximum density) LX-04 in moderate confinement (4340 steel tube at R{sub C} 32 with 1.020 inch inside diameter and 0.235 inch thick wall) at both ambient initial temperature (roughly 20 C) and at an initial temperature of 186 C. No transition to detonation was observed in a 295 mm column length for either case.

  1. The corrosion resistance of zinc coatings in the presence of boron-doped detonation nanodiamonds (DND)

    Science.gov (United States)

    Burkat, G. K.; Alexandrova, G. S.; Dolmatov, V. Yu; Osmanova, E. D.; Myllymäki, V.; Vehanen, A.

    2017-02-01

    The effect of detonation nanodiamonds, doped with boron (boron-DND) in detonation synthesis on the process of zinc electrochemical deposition from zincate electrolyte is investigated. It is shown that the scattering power (coating uniformity) increases 2-4 times (depending on the concentration of DND-boron electrolyte conductivity does not change, the corrosion resistance of Zn- DND -boron coating increases 2.6 times in 3% NaCl solution (corrosion currents) and 3 times in the climatic chamber.

  2. Simulation of the initiation of detonation in an energetic molecular crystal

    Science.gov (United States)

    Tsai, D. H.; Trevino, S. F.

    1984-12-01

    A molecular dynamical study of the detonation process in a dense system is presented. The model is a filament of a molecular crystal capable of undergoing exothermic dissociation. When the model is heated at one end, dissociation reactions start at that end and propagate along the filament. The accompanying expansion of the heated region drives a shock wave into the filament, causing further reactions due to shock heating. The results thus obtained provide a molecular description of the initiation of detonation.

  3. A stabilization mechanism for the low-velocity gaseous detonations with losses

    Science.gov (United States)

    Kasimov, Aslan; Sow, Aliou; Semenko, Roman

    2016-11-01

    Using the reactive Euler equations, we investigate numerically the nonlinear stability of steady-state one-dimensional gaseous detonations in the presence of both momentum and heat losses. Our results point to a possible stabilization mechanism for the low-velocity detonations in such systems. The mechanism stems from the existence of a one-parameter family of steady-state solutions found in Semenko et al..

  4. Analysis of the complete detonation state of solutions of TNT in advanced oxidizers

    Energy Technology Data Exchange (ETDEWEB)

    Austing, J.L.; Tulis, A.J. [IIT Research Institute, Chicago, Illinois (United States); Patel, D.L.; Heberlein, D.C. [U.S. Army, Cecom, RD et E Center, NVESD, Virginia (United States)

    1996-12-31

    Solutions of TNT in liquid oxidizers such as dinitrogen tetroxide and chlorine trifluoride are different in chemical composition from that of TNT alone, which is an organic high explosive. The experimentally-measured detonation state of such solutions was mathematically analyzed in accordance with published correlations for conventional explosives. The computations verified that the Chapman-Jouguet density and adiabatic exponent were independent of the chemical composition and were functions only of the initial density. The detonation velocity of a TNT/Dinitrogen Tetroxide change was calculated from the Hugoniot data for the constituent elements by recourse to the method developed by Walker. The calculated velocity was 6.637 km/s, which differed from the experimental value by only 1.6 percent. Detonations of 50/50 by weight TNT/Chlorine Trifluoride solutions confined in glass tubes were conducted at diameters of 131 mm, 77 mm, and 43 mm, for purposes of assessing the diameter effect. The analysis was conducted according to the correlations of Eyring et al. Extrapolation of the detonation velocity-reciprocal diameter curve to infinite diameter established that the ideal detonation velocity was 7.732 km/s. The detonation at the three finite diameters propagated at the near-ideal velocity. The critical diameter was less than 43 mm. (authors) 11 refs.

  5. A Three-Dimensional Picture of the Delayed-Detonation Model of Type Ia Supernovae

    CERN Document Server

    Bravo, Eduardo

    2007-01-01

    Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but this kind of models has been explored mainly in one dimension. Here we present new three-dimensional delayed detonation models in which the deflagraton-to-detonation transition (DDT) takes place in conditions like those favored by one-dimensional models. We have used a SPH code adapted to SNIa with algorithms devised to handle subsonic as well as supersonic combustion fronts. The starting point was a C-O white dwarf of 1.38 solar masses. When the average density on the flame surface reached 2-3x10^7 g/cm^3 a detonation was launched. The detonation wave processed more than 0.3 solar masses of carbon and oxygen, emptying the central regions of the ejecta of unburned fuel and raising ...

  6. Spontaneous Initiation of Detonations in White Dwarf Environments: Determination of Critical Sizes

    CERN Document Server

    Seitenzahl, Ivo R; Townsley, Dean M; Lamb, Don Q; Truran, James W

    2009-01-01

    Some explosion models for Type Ia supernovae (SN Ia), such as the gravitationally confined detonation (GCD) or the double detonation sub-Chandrasekhar (DDSC) models, rely on the spontaneous initiation of a detonation in the degenerate C/O material of a white dwarf. The length scales pertinent to the initiation of the detonation are notoriously unresolved in multi-dimensional stellar simulations, prompting the use of results of 1D simulations at higher resolution, such as the ones performed for this work, as guidelines for deciding whether or not conditions reached in the higher dimensional full star simulations successfully would lead to the onset of a detonation. Spontaneous initiation relies on the existence of a suitable gradient in self-ignition (induction) times of the fuel, which we set up with a spatially localized non-uniformity of temperature -- a hot spot. We determine the critical (smallest) sizes of such hot spots that still marginally result in a detonation in white dwarf matter by integrating th...

  7. Spontaneous Initiation of Detonations in White Dwarf Environments: Determination of Critical Sizes

    Science.gov (United States)

    Seitenzahl, Ivo R.; Meakin, Casey A.; Townsley, Dean M.; Lamb, Don Q.; Truran, James W.

    2009-05-01

    Some explosion models for Type Ia supernovae (SNe Ia), such as the gravitationally confined detonation (GCD) or the double detonation sub-Chandrasekhar (DDSC) models, rely on the spontaneous initiation of a detonation in the degenerate 12C}/16O} material of a white dwarf (WD). The length scales pertinent to the initiation of the detonation are notoriously unresolved in multidimensional stellar simulations, prompting the use of results of one-dimensional simulations at higher resolution, such as those performed for this work, as guidelines for deciding whether or not conditions reached in the higher dimensional full star simulations successfully would lead to the onset of a detonation. Spontaneous initiation relies on the existence of a suitable gradient in self-ignition (induction) times of the fuel, which we set up with a spatially localized nonuniformity of temperature—a hot spot. We determine the critical (smallest) sizes of such hot spots that still marginally result in a detonation in WD matter by integrating the reactive Euler equations with the hydrodynamics code FLASH. We quantify the dependences of the critical sizes of such hot spots on composition, background temperature, peak temperature, geometry, and functional form of the temperature disturbance, many of which were hitherto largely unexplored in the literature. We discuss the implications of our results in the context of modeling of SNe Ia.

  8. Use of noise attenuation modeling in managing missile motor detonation activities.

    Science.gov (United States)

    McFarland, Michael J; Watkins, Jeffrey W; Kordich, Micheal M; Pollet, Dean A; Palmer, Glenn R

    2004-03-01

    The Sound Intensity Prediction System (SIPS) and Blast Operation Overpressure Model (BOOM) are semiempirical sound models that are employed by the Utah Test and Training Range (UTTR) to predict whether noise levels from the detonation of large missile motors will exceed regulatory thresholds. Field validation of SIPS confirmed that the model was effective in limiting the number of detonations of large missile motors that could potentially result in a regulatory noise exceedance. Although the SIPS accurately predicted the impact of weather on detonation noise propagation, regulators have required that the more conservative BOOM model be employed in conjunction with SIPS in evaluating peak noise levels in populated areas. By simultaneously considering the output of both models, in 2001, UTTR detonated 104 missile motors having net explosive weights (NEW) that ranged between 14,960 and 38,938 lb without a recorded public noise complaint. Based on the encouraging results, the U.S. Department of Defense is considering expanding the application of these noise models to support the detonation of missile motors having a NEW of 81,000 lb. Recent modeling results suggest that, under appropriate weather conditions, missile motors containing up to 96,000 lb NEW can be detonated at the UTTR without exceeding the regulatory noise limit of 134 decibels (dB).

  9. Laser-shocked energetic materials with metal additives: evaluation of chemistry and detonation performance.

    Science.gov (United States)

    Gottfried, Jennifer L; Bukowski, Eric J

    2017-01-20

    A focused, nanosecond-pulsed laser has been used to ablate, atomize, ionize, and excite milligram quantities of metal-doped energetic materials that undergo exothermic reactions in the laser-induced plasma. The subsequent shock wave expansion in the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The method enables the estimation of detonation velocities based on the measured laser-induced air-shock velocities and has previously been demonstrated for organic military explosives. Here, the LASEM technique has been extended to explosive formulations with metal additives. A comparison of the measured laser-induced air-shock velocities for TNT, RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by the thermochemical code CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time (<10  μs) participation of metal additives in detonation events. The LASEM results show that while Al is mostly inert at early times in the detonation event (confirmed from large-scale detonation testing), B is active-and reducing the amount of hydrogen present during the early chemical reactions increases the resulting estimated detonation velocities.

  10. Experimental investigation into the detonation characteristics of hybrid RDX-ethylene-air mixtures

    Science.gov (United States)

    Yang, L.; Yao, J.; Yang, Z.; Xie, L.; Peng, J.; Rao, G.

    2016-09-01

    An experimental study is conducted to determine the detonation characteristics of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) particles dispersed in a gaseous fuel air mixture in a vertical detonation tube with an inner diameter of 200 mm and a height of 5400 mm. Experiments are performed in both ethylene-air mixtures and RDX-ethylene-air hybrid mixtures. The detonation front pressure and velocity are measured with six pressure transducers along the detonation tube. The results show that the addition of RDX assists 4.0 vol.% ethylene-air mixtures in achieving detonation. The detonation front pressure increases noticeably with dust concentration up to 474 g/m3 in the RDX-ethylene-air hybrid mixtures, but the velocity only increases slightly. The cellular structures of RDX-ethylene-air hybrid mixtures and ethylene-air mixtures were obtained with the use of smoked foils and exhibit irregular structures. It is found that the measured cell size has a U-shaped curve with respect to RDX concentration.

  11. Molecular-dynamics study of detonation. I. A comparison with hydrodynamic predictions

    Science.gov (United States)

    Rice, Betsy M.; Mattson, William; Grosh, John; Trevino, S. F.

    1996-01-01

    We have compared the predictions of hydrodynamic theory for the properties of an unsupported detonation with the results of a molecular dynamics simulation of such a phenomenon. The model of an energetic crystal consists of heteronuclear diatomic molecules that require energy to break the molecular bonds (at ambient pressure); substantial energy is then released upon association of the products to form homonuclear diatomic molecules. The equation of state used in the hydrodynamic theory is determined from two-dimensional molecular dynamics simulations of this model at various equilibrium conditions corresponding to volumes and temperatures appropriate to the detonation. The Chapman-Jouguet conditions of detonation were thus determined. The properties of the detonation were subsequently measured directly from two-dimensional molecular dynamics simulations of the crystal model subjected to shock initiation. The agreement between the hydrodynamic predictions and the measured properties is good. Deviations from exact agreement are attributed to slight differences in material composition in the detonation simulation compared to that of the equation of state calculations. The critical property for sustained detonation using this model appears to be the attainment of the Chapman-Jouguet density.

  12. Theoretical investigation on the heats of formation and detonation performance in polydinitroaminocubanes.

    Science.gov (United States)

    Chi, Weijie; Wang, Xiuyan; Li, Butong; Wu, Haishun

    2012-09-01

    A series of polydinitroaminocubanes have been designed computationally. We calculated the heats of formation, the detonation velocity (D) and detonation pressure (P) of the title compounds by density function theory (DFT) with 6-311 G** basis set. The relationship between the heats of formation and the molecular structures is discussed. The result shows that all cubane derivatives have high and positive heats of formation, which increase with increasing number of dinitroamino groups. The detonation performances of the title compound were estimated by Kamlet-Jacobs equation, and the result indicated that most cubane derivatives have good detonation performance over RDX (hexahydro-1,3,5-trinitro-1,3,5-trizine) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane). In addition, we also found that the heat of detonation (Q) is another very important impact in increasing detonation performance except density. The relative stabilities of the title compound are discussed in the terms of the calculated heats of formation, and the energy gaps between the frontier orbitals. The results have not only shown that these compounds may be used as high energy density compounds (HEDCs), but also provide some useful information for further investigation.

  13. Experimental investigation on noise radiation characteristics of pulse detonation engine–driven ejector

    Directory of Open Access Journals (Sweden)

    Xi-qiao Huang

    2015-06-01

    Full Text Available The noise radiation characteristics of multi-cycle pulse detonation engine with and without ejector were investigated under different operating frequencies utilizing gasoline as fuel and air as oxidizer. The straight cylindrical ejector with convergent inlet geometry was coaxially installed at different axial locations relative to the exit of the detonation tube. In all the experiments, the equivalence ratios of gasoline–air mixture and the fill fraction were 1.2 and 1.0, respectively. The experimental results implied that the addition of ejector could drastically change the far-field acoustic performance of pulse detonation engine exit and the peak sound pressure level of noise radiation was a strong function of the ejector axial position. But the peak sound pressure level was not sensitive to the operating frequencies which varied from 10 to 25 Hz. The pulse sound pressure level, however, increased with the increase in operating frequencies. The far-field jet-noise measurements of the pulse detonation engine-ejector system also showed that ejector could decrease the peak sound pressure level of pulse detonation engine. The maximum reduction was approximately 8.5 dB. For the current pulse detonation engine test conditions, an optimum ejector position was found to be a downstream axial placement of x/DPDE  = 0.5.

  14. Shock wave science and technology reference library. Vol. 4. Heterogeneous detonation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan (ed.) [Defence Research and Development Canada, Suffield, AB (Canada)

    2009-07-01

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

  15. Radioiodine therapy in benign thyroid diseases

    DEFF Research Database (Denmark)

    Bonnema, Steen Joop; Hegedüs, Laszlo

    2012-01-01

    from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or......Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems...... of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy...

  16. [Endoscopic surgery for benign esophageal diseases].

    Science.gov (United States)

    Ozawa, Soji

    2006-07-01

    Gastroesophageal reflux disease (GERD) and esophageal achalasia are common benign esophageal diseases. Today minimally invasive surgery is recommended to treat these diseases. Surgical indications for GERD are failure of medical management, medical complications attributable to a large hiatal hernia, 'atypical' symptoms (asthma, hoarseness, cough, chest pain, aspiration), etc. according to the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) guidelines. Laparoscopic Nissen fundoplication has emerged as the most widely accepted procedure for GERD patients with normal esophageal motility. Partial fundoplication (e.g., Toupet fundoplication) is also considered to decrease the possibility of postoperative dysphagia. Although pneumatic dilatation has been the first line treatment for esophageal achalasia, laparoscopic Heller myotomy and partial fundoplication (e.g., Dor fundoplication) to prevent reflux is preferred by most gastroenterologists and surgeons as the primary treatment modality. Laparoscopic surgery for GERD and esophageal achalasia are effective in most patients and safe in all patients. Finally, laparoscopic surgery should be performed only by skilled surgeons.

  17. A rare case of benign omentum teratoma

    Directory of Open Access Journals (Sweden)

    Sforza Marcos

    2012-01-01

    Full Text Available Introduction. Mature teratomas (benign cystic teratomas or dermoid cysts are among the most common ovarian tumours; however, teratomas of the omentum and mesentery are extremely rare. Teratoma in the intraperitoneal cavity is uncommon and atypical, and it is even more uncommon in adulthood. Case Outline. An 82-year-old female was admitted to our department with clinical signs of abdominal tumour. The ultrasound scan and preoperative laboratory tests were done. Explorative laparotomy revealed tumour with torsion on its pedicle at the greater omentum. After removal of the mass and the incision a tooth and hair were found, characteristics of teratoma. Conclusion. The excision was very effective and also definitive treatment for this case. The patient recovered well and was discharged 3 days later. The patient probably carried the tumour all her life asymptomatically until admission.

  18. Palladium-Catalyzed Environmentally Benign Acylation.

    Science.gov (United States)

    Suchand, Basuli; Satyanarayana, Gedu

    2016-08-05

    Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp(2) C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone.

  19. The debate over robotics in benign gynecology.

    Science.gov (United States)

    Rardin, Charles R

    2014-05-01

    The debate over the role of the da Vinci surgical robotic platform in benign gynecology is raging with increasing fervor and, as product liability issues arise, greater financial stakes. Although the best currently available science suggests that, in the hands of experts, robotics offers little in surgical advantage over laparoscopy, at increased expense, the observed decrease in laparotomy for hysterectomy is almost certainly, at least in part, attributable to the availability of the robot. In this author's opinion, the issue is not whether the robot has any role but rather to define the role in an institutional environment that also supports the safe use of vaginal and laparoscopic approaches in an integrated minimally invasive surgery program. Programs engaging robotic surgery should have a clear and self-determined regulatory process and should resist pressures in place that may preferentially support robotics over other forms of minimally invasive surgery.

  20. Benign familial polycythaemia in a young male

    Directory of Open Access Journals (Sweden)

    Somanth Maitra

    2012-01-01

    Full Text Available Polycythaemia has been reported rarely as a familial condition. There is evidence to suggest transmission as a Mendelian dominant trait, but recessive inheritance has also been described. We present here a case of benign familial polycythaemia in a 25-year-old male with similar presentation in his family members. Our patient presented with reddish discolouration of eyes, early satiety , weight loss and itching at intervals for four years. An additional examination revealed red beefy tongue and Grade III clubbing. The importance of presenting this case lies in the fact that the prognosis appears to be good in these patients, but regular observation is necessary as Kiladjian and colleagues have mentioned that there is a risk of leukaemia, thrombosis and myelofibrosis in these patients later on, as the idiopathic erythrocytosis group contains a certain number of polycythaemia patients.

  1. Risk stratification for benign prostatic hyperplasia.

    Science.gov (United States)

    Zattoni, Fabio; Ficarra, Vincenzo; Novara, Giacomo

    2017-03-18

    Benign prostatic hyperplasia (BPH) represents an important public health problem in ageing men due to frequently associated lower urinary tract symptoms (LUTS), which may impair quality of life. BPH is also a progressive disease, mainly characterized by a worsening of LUTS over time, and in some patients by the occurrence of serious outcomes such as acute urinary retention and need for BPH-related surgery. The management of BPH and LUTS in men should move forward its focus on symptom control only. Indeed, the goals of therapy for BPH are not only to improve bothersome LUTS but also to identify those patients at risk of unfavourable outcomes in order to optimize their management and reduce complications. Risk stratification and tailored treatment should improve the reductions in both symptoms and the long-term consequences of BPH and BPH treatments. To do this, clinicians need to know possible factors that may support the develop of PBH and possible risks due to the BPH itself.

  2. Levodopa-Responsive Benign Tremulous Parkinsonism

    Directory of Open Access Journals (Sweden)

    Osamu Kano

    2013-08-01

    Full Text Available Background: Benign tremulous parkinsonism (BTP is a tremor dominant syndrome characterized by mild, levodopa-resistant parkinsonism with limited disability or progression. Case Presentation: A 56-year-old woman presented with a 2-year history of tremor. Neurological examination revealed right-hand rest tremor and slow finger tapping with decreased amplitude; however, we did not observe posture tremor, rigidity, bradykinesia, or posture disability. She was diagnosed with Parkinson's disease (PD and received levodopa/carbidopa, effectively treating her rest tremor. At the age of 61 years, reoccurrence of the rest tremor was successfully treated again with levodopa/carbidopa and selegiline. Approximately 11 years have passed since symptom onset and the patient shows no further disease progression. Conclusion: This case broadens the characterization of BTP to include levodopa-responsive PD.

  3. Climatic variations and benign paroxysmal positional vertigo

    Institute of Scientific and Technical Information of China (English)

    Basil M.N. Saeed; Alyaa Farouk Omari

    2016-01-01

    Benign paroxysmal positional vertigo (BPPV) is probably the most common diagnosis at vertigo clinics. Seasonal cycles of several human illnesses could be attributed variously to changes in atmospheric or weather conditions. In this retrospective study, patients with BPPV from January 2010 to December 2012 were studied, and their charts were reviewed. Statistical analysis revealed a statistically significant difference in patients' numbers among different months of the year. Also there is a significant statistical correlation between the numbers of patients with climatic variations especially the temperature. The present paper discusses the possible explanations for these results which confirms the seasonal variations in BPPV, together with a review of literature to view the possible associations with other disorders that causes such sea-sonality.

  4. Endoscopic management of benign biliary strictures.

    Science.gov (United States)

    Rustagi, Tarun; Jamidar, Priya A

    2015-01-01

    Benign biliary strictures are a common indication for endoscopic retrograde cholangiopancreatography (ERCP). Endoscopic management has evolved over the last 2 decades as the current standard of care. The most common etiologies of strictures encountered are following surgery and those related to chronic pancreatitis. High-quality cross-sectional imaging provides a road map for endoscopic management. Currently, sequential placement of multiple plastic biliary stents represents the preferred approach. There is an increasing role for the treatment of these strictures using covered metal stents, but due to conflicting reports of efficacies as well as cost and complications, this approach should only be entertained following careful consideration. Optimal management of strictures is best achieved using a team approach with the surgeon and interventional radiologist playing an important role.

  5. Standard NIJ 0115.00 za testiranje otpornosti zaštitnih prsluka na ubode nožem i predmetima sa oštrim vrhom / NIJ 0115.00 standard for testing stab resistance of body armor

    Directory of Open Access Journals (Sweden)

    Đuro Jovanić

    2008-04-01

    Full Text Available Standard NIJ 0115.00 (prema Nacionalnom institutu pravde SAD, namenjen je za utvrđivanje minimuma tehničkih zahteva i metoda ispitivanja otpornosti zaštitnih prsluka, koji treba da zaštite gornji deo tela od uboda nožem i predmetima sa oštrim vrhom. Područje primene ovog standarda ograničeno je samo na pretnje ubodima, a ne na balističke pretnje, poput onih koje su obuhvaćene standardom NIJ 0101.04 za testiranje balističke otpornosti zaštitnih prsluka. / In this work made presentation of NIJ 0115.04. (National Institute of Justice standard, witch purpose is to establish minimum performance requirements and methods of testing for the stab resistance of body armor intended to protect the torso against slash and stab threats. The scope of the standard is limited to stab resistance only; the standard does not address ballistic threats, as those are covered by NIJ Standard 0101.04. Ballistic Resistance of Personal Body Armor.

  6. To Observe the Curative Effect of Combined Abdominal Massage Treatment of Functional Constipation of Deep stab Tianshu%深刺天枢结合摩腹治疗功能性便秘的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    万兴; 于建

    2014-01-01

    目的观察深刺天枢穴结合摩腹治疗结肠慢传输便秘的临床疗效。方法纳入符合诊断标准的功能性便秘患者30例,观察深刺天枢结合摩腹治疗前后的症状评分变化。结果患者接受治疗后第1w、第4w及治疗结束后第4w便秘症状评分明显低于治疗前。结论深刺天枢穴结合摩腹治疗功能性便秘有较好的临床疗效。%Objective To observe the deep stab Tianshu clinical ef icacy of abdominal massage therapy slow transit constipation. Methods The diagnostic criteria included patients with constipation functional 30 cases were observed deep stab Tianshu combined symptom scores before and after treatment of abdominal massage. Results Patients receiving treatment after the first week, the first four weeks and four weeks after the end of treatment of constipation symptom score was significantly lower than before treatment. Conclusion The combination of deep stab Tianshu Mount abdominal treatment of functional constipation have bet er clinical ef icacy.

  7. HOW BENIGN IS BPPV IN THE ELDERLY?

    Directory of Open Access Journals (Sweden)

    Rama Krishna

    2015-01-01

    Full Text Available Geriatric population in India is rapidly increasing. According to one estimate the number of persons above the age of 60 years is 76.6 million in India. India as the second most populous country in the world, with elderly people constituting 7.7% of total population. The morbidity in this age group is often due to increased incidence of falls. It is often preceded with spells of dizziness and often associated with vestibular disorders. Peripheral vestibular disorders often difficult to evaluate at the time of fall and only realized after the fall. Peripheral vestibular disorders like Benign Paroxysmal Positional Vertigo (BPPV, Vestibulopathy, Vestibular Neuritis are some of the disorders that affect geriatric population that affect the functional ability in ‘activities of daily living (ADL. BPPV has been frequently found to be more common with advancing age. One simple test to assess ADL (Activities of Daily Living is TUG test (Timed Up and Go. A score of 11.1 seconds or more on TUG test was correlated with 80% chance of a fall in the elderly. Hence a study is undertaken to evaluate peripheral vestibular disorders in elderly with special reference to BPPV along with their performance on TUG (Timed Up and Go test. Benign Paroxysmal Positional Vertigo (BPPV has been found to be most common vestibular disorder in the elderly . One out of four elderly with Peripheral vestibular disorder has a risk of ‘fall’. BPPV is the most common peripheral vestibular disorder leading to ‘risk of fall’ three times more among the elderly after 75years .

  8. Large mid-esophageal granular cell tumor: benign versus malignant

    Directory of Open Access Journals (Sweden)

    Prarthana Roselil Christopher

    2015-06-01

    Full Text Available Granular cell tumors are rare soft tissue neoplasms, among which only 2% are malignant, arising from nervous tissue. Here we present a case of a large esophageal granular cell tumor with benign histopathological features which metastasized to the liver, but showing on positron emission tomography-computerized tomography standardized uptake value suggestive of a benign lesion.

  9. Perfusion MR imaging for differentiation of benign and malignant meningiomas

    NARCIS (Netherlands)

    Zhang, Hao; Rodiger, Lars A.; Shen, Tianzhen; Miao, Jingtao; Oudkerk, Matthijs

    2008-01-01

    Introduction Our purpose was to determine whether perfusion MR imaging can be used to differentiate benign and malignant meningiomas on the basis of the differences in perfusion of tumor parenchyma and/or peritumoral edema. Methods A total of 33 patients with preoperative meningiomas (25 benign and

  10. Single benign metastasising leiomyoma of an inguinal lymph node.

    NARCIS (Netherlands)

    Laban, KG; Tobon-Morales, Roberto; Hodge, Janice; Schreuder, HWR

    2016-01-01

    Benign metastasising leiomyoma (BML) is a rare benign disease associated with uterine leiomyoma and history of uterine surgery. It most frequently occurs in premenopausal woman, with a pulmonary localisation, and consisting of multiple nodules. We present an uncommon case of a 69-year-old woman with

  11. The effect of detonation wave incidence angle on the acceleration of flyers by explosives heavily laden with inert additives

    Science.gov (United States)

    Loiseau, Jason; Georges, William; Frost, David L.; Higgins, Andrew J.

    2017-01-01

    The incidence angle of a detonation wave in a conventional high explosive influences the acceleration and terminal velocity of a metal flyer by increasing the magnitude of the material velocity imparted by the transmitted shock wave as the detonation is tilted towards normal loading. For non-ideal explosives heavily loaded with inert additives, the detonation velocity is typically subsonic relative to the flyer sound speed, leading to shockless accelerations when the detonation is grazing. Further, in a grazing detonation the particles are initially accelerated in the direction of the detonation and only gain velocity normal to the initial orientation of the flyer at later times due to aerodynamic drag as the detonation products expand. If the detonation wave in a non-ideal explosive instead strikes the flyer at normal incidence, a shock is transmitted into the flyer and the first interaction between the particle additives and the flyer occurs due to the imparted material velocity from the passage of the detonation wave. Consequently, the effect of incidence angle and additive properties may play a more prominent role in the flyer acceleration. In the present study we experimentally compared normal detonation loadings to grazing loadings using a 3-mm-thick aluminum slapper to impact-initiate a planar detonation wave in non-ideal explosive-particle admixtures, which subsequently accelerated a second 6.4-mm-thick flyer. Flyer acceleration was measured with heterodyne laser velocimetry (PDV). The explosive mixtures considered were packed beds of glass or steel particles of varying sizes saturated with sensitized nitromethane, and gelled nitromethane mixed with glass microballoons. Results showed that the primary parameter controlling changes in flyer velocity was the presence of a transmitted shock, with additive density and particle size playing only secondary roles. These results are similar to the grazing detonation experiments, however under normal loading the

  12. Prediction of the Chapman–Jouguet chemical equilibrium state in a detonation wave from first principles based reactive molecular dynamics

    OpenAIRE

    Guo, Dezhou; Zybin, Sergey V.; An, Qi; Goddard, William A.; Huang, Fenglei

    2016-01-01

    The combustion or detonation of reacting materials at high temperature and pressure can be characterized by the Chapman–Jouguet (CJ) state that describes the chemical equilibrium of the products at the end of the reaction zone of the detonation wave for sustained detonation. This provides the critical properties and product kinetics for input to macroscale continuum simulations of energetic materials. We propose the ReaxFF Reactive Dynamics to CJ point protocol (Rx2CJ) for predicting the CJ s...

  13. Counting vacancies and nitrogen-vacancy centers in detonation nanodiamond

    Science.gov (United States)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian; Boothroyd, Chris B.; Hocking, Rosalie K.; Ōsawa, Eiji; Nicholls, Rebecca J.

    2016-05-01

    Detonation nanodiamond particles (DND) contain highly-stable nitrogen-vacancy (N-V) centers, making it important for quantum-optical and biotechnology applications. However, due to the small particle size, the N-V concentrations are believed to be intrinsically very low, spawning efforts to understand the formation of N-V centers and vacancies, and increase their concentration. Here we show that vacancies in DND can be detected and quantified using simulation-aided electron energy loss spectroscopy. Despite the small particle size, we find that vacancies exist at concentrations of about 1 at%. Based on this experimental finding, we use ab initio calculations to predict that about one fifth of vacancies in DND form N-V centers. The ability to directly detect and quantify vacancies in DND, and predict the corresponding N-V formation probability, has a significant impact to those emerging technologies where higher concentrations and better dispersion of N-V centres are critically required.Detonation nanodiamond particles (DND) contain highly-stable nitrogen-vacancy (N-V) centers, making it important for quantum-optical and biotechnology applications. However, due to the small particle size, the N-V concentrations are believed to be intrinsically very low, spawning efforts to understand the formation of N-V centers and vacancies, and increase their concentration. Here we show that vacancies in DND can be detected and quantified using simulation-aided electron energy loss spectroscopy. Despite the small particle size, we find that vacancies exist at concentrations of about 1 at%. Based on this experimental finding, we use ab initio calculations to predict that about one fifth of vacancies in DND form N-V centers. The ability to directly detect and quantify vacancies in DND, and predict the corresponding N-V formation probability, has a significant impact to those emerging technologies where higher concentrations and better dispersion of N-V centres are critically

  14. The Effect of the Pre-Detonation Stellar Internal Velocity Profile on the Nucleosynthetic Yields in Type Ia Supernova

    CERN Document Server

    Kim, Yeunjin; Graziani, Carlo; Meyer, B S; Lamb, D Q; Truran, J W

    2013-01-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of alpha-particle nuclei, including Ni56, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Al...

  15. Initiation of detonation by impact on granular explosives; Contribution a l'etude de la generation de la detonation provoquee par impact sur un explosif

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-05-15

    A good number of experiments have shown up the particular behaviour of granular explosives when they are detonated by barrier transmitted shocks. Similar results can be obtained when the shock is induced by impact. In this case the pressure signal shape applied at the explosive is better known and both its intensity and duration can be varied. By using a mathematical model in which the law of chemical kinetics is a linear function of pressure, and different temperatures are used for solids and gases, it is possible to describe most of the behaviour of detonation initiation in solid granular explosives. (author) [French] De nombreuses etudes experimentales ont montre le comportement particulier des explosifs granulaires lors de la detonation provoquee par choc transmis a travers une barriere. Les memes resultats peuvent etre obtenus lorsque la detonation est engendree par impact. Dans ce cas, la forme du signal de pression induit dans l'explosif est mieux connue, et il est possible d'en faire varier l'intensite et la duree d'application. Un modele mathematique utilisant une loi de cinetique chimique fonction lineaire de la pression et ou les temperatures des etats solide et gazeux pendant la reaction sont differenciees, permet de retrouver la plupart des caracteres specifiques de la generation dans un explosif solide granulaire. (auteur)

  16. A thermochemical model for shock-induced reactions (heat detonations) in solids

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, M.B. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (US))

    1990-02-01

    Recent advances in studies of shock-induced chemistry in reactive solids have led to the recognition of a new class of energetic materials which are unique in their response to shock waves. Experimental work has shown that chemical energy can be released on a time scale shorter than shock-transit times in laboratory samples. However, for many compositions, the reaction products remain in the condensed state upon release from high pressure, and no sudden expansion takes place. Nevertheless, if such a reaction is sufficiently rapid, it can be modeled as a type of detonation, termed heat detonation'' in the present paper. It is shown that unlike an explosive detonation, an unsupported heat detonation will decay to zero unless certain conditions are met. An example of such a reaction is Fe{sub 2}O{sub 3} +2Al+shock{r arrow}Al{sub 2} O{sub 3} +2Fe (the standard thermite reaction). A shock-wave equation of state is determined from a mixture theory for reacted and unreacted porous thermite. The calculated shock temperatures are compared to experimentally measured shock temperatures, demonstrating that a shock-induced reaction takes place. Interpretation of the measured temperature history in the context of the thermochemical model implies that the principal rate-controlling kinetic mechanism is dynamic mixing at the shock front. Despite the similarity in thermochemical modeling of heat detonations to explosive detonations, the two processes are qualitatively very different in reaction mechanism as well as in the form the energy takes upon release, with explosives producing mostly work and heat detonations producing mostly heat.

  17. Three-dimensional CLEM-LES of irregular detonation propagation

    Science.gov (United States)

    Maxwell, Brian; Radulescu, Matei

    2016-11-01

    Recently, thin-channel experiments and 2D simulations have been conducted in order to investigate the effect of turbulent mixing rates on the structure of irregular detonation wave propagation. Furthermore, the dependence of the observed cell pattern, and also the reaction zone thickness, on the mixing of burned products with pockets of unburned gases, was investigated. The current work now includes 3D simulations, which are conducted to provide further validation of, and insight into, the 2D results. All simulations have been conducted using the Compressible Linear Eddy Model for Large Eddy Simulation (CLEM-LES). To date, the 3D results are found to match closely the previous 2D results. The agrreement is partly due to sufficient resolution of the large scale fluid motions, which are observed experimentally to be predominant in only two directions. Furthermore, the CLEM-LES methodology incorporates 3D mixing effects at the subgrid level. Finally, it was found that turbulent fluctuations on the subgrid were found to give rise to statistically lower than average propagation velocities on the wave front. This lead to longer ignition delays for large amounts of gas passing through the wave, giving rise to the unburned pockets of gas observed experimentally. Authors would like to acknowledge NSERC and Shell for project funding.

  18. Neutrinos from Type Ia Supernovae: The Gravitationally Confined Detonation Scenario

    CERN Document Server

    Wright, Warren P; Ohlmann, Sebastian T; Roepke, Friedrich K; Scholberg, Kate; Seitenzahl, Ivo R

    2016-01-01

    Despite their use as cosmological distance indicators and their importance in the chemical evolution of Galaxies, the unequivocal identification of the progenitor systems and explosion mechanism of normal Type Ia supernova (SN Ia) remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbon-oxygen white dwarf but the exact explosion mechanism is still a matter of debate. Observation of a Galactic SN Ia would be of immense value in answering the many open questions related to these events. One potentially useful source of information about the explosion mechanism and progenitor is the neutrino signal. In this paper we compute the expected neutrino signal from a Gravitationally Confined Detonation (GCD) explosion scenario for a SN~Ia and show how the flux at Earth contains features in time and energy unique to this scenario. We then calculate the expected event rates in the Super-K, Hyper-K, JUNO, DUNE, and IceCube detectors and find both Hyper-K and IceCube would se...

  19. Effect of spatial discretization of energy on detonation wave propagation

    CERN Document Server

    Mi, XiaoCheng; Higgins, Andrew J

    2016-01-01

    Detonation propagation in the limit of highly spatially discretized energy sources is investigated. The model of this problem begins with a medium consisting of a calorically perfect gas with a prescribed energy release per unit mass. The energy release is collected into sheet-like sources that are now embedded in an inert gas that fills the spaces between them. The release of energy in the first sheet results in a planar blast wave that propagates to the next source, which is triggered after a prescribed delay, generating a new blast, and so forth. The resulting wave dynamics as the front passes through hundreds of such sources is computationally simulated by numerically solving the governing one-dimensional Euler equations in the lab-fixed reference frame. The average wave speed for each simulation is measured once the wave propagation has reached a quasi-periodic solution. Velocities in excess of the CJ speed are found as the sources are made increasingly discrete, with the deviation above CJ being as grea...

  20. Recent papers from DX-1, detonation science and technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    Over the past year members of DX-1 have participated in several conferences where presentations were made and papers prepared for proceedings. There have also been several papers published in or submitted to refereed journals for publication. Rather that attach all these papers to the DX-1 Quarterly Report, we decided to put them in a Los Alamos report that could be distributed to those who get the quarterly, as well as others that have an interest in the work being done in DX-1 both inside and outside the Laboratory. This compilation does not represent all the work reported during the year because some people have chosen not to include their work here. In particular, there were a number of papers relating to deflagration-to-detonation modeling that were not included. However, this group of papers does present a good picture of much of the unclassified work being done in DX-1. Several of the papers include coauthors from other groups or divisions at the Laboratory, providing an indication of the collaborations in which people in DX-1 are involved. Discussed topics of submitted papers include: shock compression of condensed matter, pyrotechnics, shock waves, molecular spectroscopy, sound speed measurements in PBX-9501, chemical dimerization, and micromechanics of spall and damage in tantalum.

  1. Analysis of supercritical vapor explosions using thermal detonation wave theory

    Energy Technology Data Exchange (ETDEWEB)

    Shamoun, B.I.; Corradini, M.L. [Univ. of Wisconsin, Madison, WI (United States)

    1995-09-01

    The interaction of certain materials such as Al{sub 2}O{sub 3} with water results in vapor explosions with very high (supercritical) pressures and propagation velocities. A quasi-steady state analysis of supercritical detonation in one-dimensional multiphase flow was applied to analyze experimental data of the KROTOS (26-30) set of experiments conducted at the Joint Research Center at Ispra, Italy. In this work we have applied a new method of solution which allows for partial fragmentation of the fuel in the shock adiabatic thermodynamic model. This method uses known experiment values of the shock pressure and propagation velocity to estimate the initial mixing conditions of the experiment. The fuel and coolant were both considered compressible in this analysis. In KROTOS 26, 28, 29, and 30 the measured values of the shock pressure by the experiment were found to be higher than 25, 50, 100, and 100 Mpa respectively. Using the above data for the wave velocity and our best estimate for the values of the pressure, the predicted minimum values of the fragmented mass of the fuel were found to be 0.026. 0.04, 0.057, and 0.068 kg respectively. The predicted values of the work output corresponding to the above fragmented masses of the fuel were found to be 40, 84, 126, and 150 kJ respectively, with predicted initial void fractions of 112%, 12.5%, 8%, and 6% respectively.

  2. Searching for "environmentally-benign" antifouling biocides.

    Science.gov (United States)

    Cui, Yan Ting; Teo, Serena L M; Leong, Wai; Chai, Christina L L

    2014-05-26

    As the result of the ecological impacts from the use of tributyltins (TBT) in shipping, environmental legislation for the registration of chemicals for use in the environment has grown to a monumental challenge requiring product dossiers to include information on the environmental fate and behavior of any chemicals. Specifically, persistence, bioaccumulation and toxicity, collectively known as PBT, are properties of concern in the assessment of chemicals. However, existing measurements of PBT properties are a cumbersome and expensive process, and thus not applied in the early stages of the product discovery and development. Inexpensive methods for preliminary PBT screening would minimize risks arising with the subsequent registration of products. In this article, we evaluated the PBT properties of compounds reported to possess anti-fouling properties using QSAR (quantitative structure-activity relationship) prediction programs such as BIOWIN™ (a biodegradation probability program), KOWWIN™ (log octanol-water partition coefficient calculation program) and ECOSAR™ (Ecological Structure Activity Relationship Programme). The analyses identified some small (Mr < 400) synthetic and natural products as potential candidates for environmentally benign biocides. We aim to demonstrate that while these methods of estimation have limitations, when applied with discretion, they are powerful tools useful in the early stages of research for compound selection for further development as anti-foulants.

  3. Benign Paroxysmal Positional Vertigo: An Integrated Perspective

    Directory of Open Access Journals (Sweden)

    Kourosh Parham

    2014-01-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV, the most common cause of dizziness, occurs in all age groups. It presents with vertigo on head movement, but in older patients presentation may be typical and thus accounting for a low recognition rate in the primary care setting. It may be recurrent in up to 50% of cases. BPPV is associated with displacement of fragments of utricular otoconia into the semicircular canals, most commonly the posterior semicircular canal. Otoconia are composed of otoconin and otolin forming the organic matrix on which calcium carbonate mineralizes. Otoconia may fragment with trauma, age, or changes in the physiology of endolymph (e.g., pH and calcium concentration. Presentation varied because otoconia fragments can be displaced into any of the semicircular canals on either (or both side and may be free floating (canalolithiasis or attached to the cupula (cupulolithiasis. Most cases of BPPV are idiopathic, but head trauma, otologic disorders, and systemic disease appear to be contributory in a subset. Positional maneuvers are used to diagnose and treat the majority of cases. In rare intractable cases surgical management may be considered. A strong association with osteoporosis suggests that idiopathic BPPV may have diagnostic and management implications beyond that of a purely otologic condition.

  4. Clinical Investigation of Benign Asbestos Pleural Effusion.

    Science.gov (United States)

    Fujimoto, Nobukazu; Gemba, Kenichi; Aoe, Keisuke; Kato, Katsuya; Yokoyama, Takako; Usami, Ikuji; Onishi, Kazuo; Mizuhashi, Keiichi; Yusa, Toshikazu; Kishimoto, Takumi

    2015-01-01

    There is no detailed information about benign asbestos pleural effusion (BAPE). The aim of the study was to clarify the clinical features of BAPE. The criteria of enrolled patients were as follows: (1) history of asbestos exposure; (2) presence of pleural effusion determined by chest X-ray, CT, and thoracentesis; and (3) the absence of other causes of effusion. Clinical information was retrospectively analysed and the radiological images were reviewed. There were 110 BAPE patients between 1991 and 2012. All were males and the median age at diagnosis was 74 years. The median duration of asbestos exposure and period of latency for disease onset of BAPE were 31 and 48 years, respectively. Mean values of hyaluronic acid, adenosine deaminase, and carcinoembryonic antigen in the pleural fluid were 39,840 ng/mL, 23.9 IU/L, and 1.8 ng/mL, respectively. Pleural plaques were detected in 98 cases (89.1%). Asbestosis was present in 6 (5.5%) cases, rounded atelectasis was detected in 41 (37.3%) cases, and diffuse pleural thickening (DPT) was detected in 30 (27.3%) cases. One case developed lung cancer (LC) before and after BAPE. None of the cases developed malignant pleural mesothelioma (MPM) during the follow-up.

  5. Clinical Investigation of Benign Asbestos Pleural Effusion

    Directory of Open Access Journals (Sweden)

    Nobukazu Fujimoto

    2015-01-01

    Full Text Available There is no detailed information about benign asbestos pleural effusion (BAPE. The aim of the study was to clarify the clinical features of BAPE. The criteria of enrolled patients were as follows: (1 history of asbestos exposure; (2 presence of pleural effusion determined by chest X-ray, CT, and thoracentesis; and (3 the absence of other causes of effusion. Clinical information was retrospectively analysed and the radiological images were reviewed. There were 110 BAPE patients between 1991 and 2012. All were males and the median age at diagnosis was 74 years. The median duration of asbestos exposure and period of latency for disease onset of BAPE were 31 and 48 years, respectively. Mean values of hyaluronic acid, adenosine deaminase, and carcinoembryonic antigen in the pleural fluid were 39,840 ng/mL, 23.9 IU/L, and 1.8 ng/mL, respectively. Pleural plaques were detected in 98 cases (89.1%. Asbestosis was present in 6 (5.5% cases, rounded atelectasis was detected in 41 (37.3% cases, and diffuse pleural thickening (DPT was detected in 30 (27.3% cases. One case developed lung cancer (LC before and after BAPE. None of the cases developed malignant pleural mesothelioma (MPM during the follow-up.

  6. Benign encephalopathy of pregnancy. Preliminary clinical observations.

    Science.gov (United States)

    Poser, C M; Kassirer, M R; Peyser, J M

    1986-01-01

    A survey of 67 pregnancies in 51 professional women (physicians, psychologists, nurses, administrators, etc.) revealed the occurrence of symptoms of cognitive dysfunction such as forgetfulness, disorientation, confusion and reading difficulties in 28 pregnancies occurring in 21 women. These were unrelated to such factors as age of delivery, percentage weight gain, the baby's sex or birth weight, alcohol consumption, smoking, a history of migraine or allergy or other symptoms occurring during pregnancy such as sleepiness and lack of concentration, irritability, loss of interest in job or nightmares. Nor was there any correlation with hypertension, proteinuria, glycosuria, ketonuria, anemia, or morning sickness. Furthermore, these cognitive disturbances were not related to depression or sleep deprivation. Despite these symptoms, none of the women suffering from them were forced to interrupt their professional activities during pregnancy. The syndrome of benign encephalopathy of pregnancy should be recognized so that simple precautions can be taken to prevent any interference with professional or other activities. The etiology of the syndrome is unknown.

  7. Treating benign prostatic hyperplasia with botulinum neurotoxin.

    Science.gov (United States)

    Brisinda, G; Vanella, S; Marniga, G; Crocco, A; Maria, G

    2011-01-01

    Botulinum toxin (BoNT) has been increasingly used in the interventional treatment of several disorders; the use of this agent has extended to a plethora of conditions including focal dystonia, spasticity, inappropriate contraction in most gastrointestinal sphincters, eye movement disorders, hyperhidrosis, genitourinary disorders and aesthetically undesirable hyperfunctional facial lines. In addition, BoNT is being investigated for the control of pain, and for the management of tension or migraine headaches and myofascial pain syndrome. Benign prostatic hyperplasia (BPH) is a common condition in ageing men; the goal of therapy is to reduce the lower urinary tract symptoms (LUTS) associated with BPH and to improve the quality of life. However, medical treatment, including drugs that relax smooth muscle within the prostate and drugs that shrink the gland are not totally effective or without complications. The standard surgical treatment for BPH is progressively changing to minimally invasive therapies, but none of them has provided clear results. The use of BoNT-A to inhibit the autonomic efferent effects on prostate growth and contraction, and inhibit the abnormal afferent effects on prostate sensation, might be an alternative treatment for BPH. BoNT injections have several advantages over drugs and surgical therapies in the management of intractable or chronic disease; systemic pharmacologic effects are rare, permanent destruction of tissue does not occur, and graded degrees of relaxation may be achieved by varying the dose injected. In this paper, clinical experience over the last years with BoNT in BPH impaired patients will be illustrated.

  8. [Minimally Invasive Treatment of Esophageal Benign Diseases].

    Science.gov (United States)

    Inoue, Haruhiro

    2016-07-01

    As a minimally invasive treatment of esophageal achalasia per-oral endoscopic myotomy( POEM) was developed in 2008. More than 1,100 cases of achalasia-related diseases received POEM. Success rate of the procedure was more than 95%(Eckerdt score improvement 3 points and more). No serious( Clavian-Dindo classification III b and more) complication was experienced. These results suggest that POEM becomes a standard minimally invasive treatment for achalasia-related diseases. As an off-shoot of POEM submucosal tumor removal through submucosal tunnel (per-oral endoscopic tumor resection:POET) was developed and safely performed. Best indication of POET is less than 5 cm esophageal leiomyoma. A novel endoscopic treatment of gastroesophageal reflux disease (GERD) was developed. Anti-reflux mucosectomy( ARMS) is nearly circumferential mucosal reduction of gastric cardia mucosa. ARMS is performed in 56 consecutive cases of refractory GERD. No major complications were encountered and excellent clinical results. Best indication of ARMS is a refractory GERD without long sliding hernia. Longest follow-up case is more than 10 years. Minimally invasive treatments for esophageal benign diseases are currently performed by therapeutic endoscopy.

  9. [Benign pleural effusion caused by asbestos exposure].

    Science.gov (United States)

    Vieira, J R; Alfarroba, E; Viegas, J; Freitas e Costa, M

    1992-05-01

    The Authors present the first case described among us of benign pleural effusion of an asbestotic origin. They stress the importance of thoracoscopy (pleuroscopy) in the diagnosis of this situation. Attention is drawn to the fact that asbestotic lesions and asbestotic bodies have been found in the lung and, in particular, in the parietal pleura as well. They emphasize the fact that exposure to asbestos was not realized by the patient, which made the clarification of the situation more difficult. It was a CT scan that showed the signs suggestive of exposure to asbestos which raised the diagnostic suspicion. They conclude that every patient with a pleural effusion must be thoroughly questioned about exposure to asbestos. Even if the exposure is accepted, they consider that one should proceed to a pleuro-pulmonar biopsy by thoracoscopy. This biopsy allows demonstration of the characteristic histopathological lesions and rule out other etiologies, namely malignancy and tuberculosis. They suggest that these patients must be highly motivated to stop any smoking and kept under periodic surveillance.

  10. Transurethral electrochemical treatment of benign prostatic hyperplasia

    Institute of Scientific and Technical Information of China (English)

    张民; 龚侃; 李宁; 曾荔; 那彦群

    2003-01-01

    Objective To study the mechanism and feasibility of transurethral electrochemical therapy for the treatment of benign prostatic hyperplasia (BPH). Methods Between March 1998 and March 2000, specifically designed devices and catheters for electrochemical therapy were applied to 6 prostate specimens obtained by suprapubic prostatectomy in order to treat BPH patients with urinary retention for whom surgery was contraindicated. Sixteen patients (with a mean age of 77.3 years old) underwent electrical treatment totaling 160-220 coulombs under topical urethral anesthesia for 68-132 min. The catheters remained inside the patient for 7-10 d. Results Irreversible destructive changes occurred within cathodal tissue, while carbonization occurred within anodic tissue. The radius of tissue change was 7-8 mm and 1-2 mm, respectively. In vivo trial: 11 (69%) patients could be weaned off the catheters with satisfactory urination. Three months after therapy, the mean international prostate symptom score (IPSS) was 14.5, mean peak flow rate was 10.5 ml/s, and mean residual urine was 39 ml. No serious complications were observed. Conclusion Transurethral electrochemical treatment is potentially a minimally invasive alternative for treatment of BPH, especially for elderly patients at high risk.

  11. Transurethral microwave thermotherapy for benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    Rubeinstein Jonathan N.

    2003-01-01

    Full Text Available Transurethral resection of the prostate (TURP remains the gold standard for treatment of benign prostatic hyperplasia (BPH. In general, while this procedure is safe, patients require a spinal, epidural, or general anesthesia and often several days of hospital stay; the potential morbidity and mortality limits the use of TURP in high-risk patients. Pharmacotherapy has been recommended as a first-line therapy for all patients with mild to moderate symptoms. Patients are oftentimes enthusiastic if they are offered a one-time method to treat lower urinary tract symptoms secondary to BPH, provided that the method offers reduced risk and allows an efficacy equal to that of medical therapy. One such method is transurethral microwave thermotherapy (TUMT. TUMT involves the insertion of a specially designed urinary catheter with a microwave antenna, which heats the prostate and destroys hyperplastic prostate tissue. TUMT allows the avoidance of general or regional anesthesia, and results in minimal blood loss and fluid absorption. In this review, the authors discussed the current indications and outcome of TUMT, including the history of the procedure, the mechanism of action, the indications for TUMT, the pre-operative considerations, the patient selection, the results in terms of efficacy, by comparing TUMT vs. Sham, TUMT vs. Alpha-blocker and TUMT vs. TURP. Finally, the complications are presented, as well as other uses and future directions of the procedure. The authors concluded that TUMT is a safe and effective minimally invasive alternative to treatment of symptomatic BPH.

  12. MRI findings of benign monomelic amyotrophy of lower limb.

    Science.gov (United States)

    Hamano, T; Mutoh, T; Hirayama, M; Ito, K; Kimura, M; Aita, T; Kiyosawa, K; Ohtaki, T; Kuriyama, M

    1999-06-01

    We report here magnetic resonance imaging (MRI) findings of two patients with benign monomelic amyotrophy of lower limb. Both subjects showed unilateral amyotrophy of the lower limb with a benign clinical course, and the affected muscles demonstrated neurogenic changes. On T1- and T2-weighted MRI, marked atrophy and increased signal intensity were found mainly in gastrocnemius and soleus muscles. Moreover, MRI examination also revealed that thigh muscles including semitendinosus, semimembranosus, and vastus intermedius and lateralis muscles were involved in one of the patients. We concluded that muscle MRI is very useful for detecting affected muscles, especially deep skeletal muscles in patients with benign monomelic amyotrophy of lower limb.

  13. FDG PET/CT appearance of benign pilomatricoma.

    Science.gov (United States)

    Bhatt, Manoj Kumar; Sommerville, Ryan; Ravi Kumar, Aravind S

    2012-07-01

    A 56-year-old patient was referred for FDG PET/CT with a right preauricular lymph node fine-needle biopsy, suggesting poorly differentiated carcinoma and no obvious primary lesion. There was intense FDG uptake in the right preauricular nodule. The node was excised, and formal histology demonstrated a benign pilomatricoma rather than malignancy. Pilomatricoma is uncommon in adults and an unusual cause for marked FDG uptake, likely due to foreign body inflammation. Pilomatricoma can be either benign or malignant. The marked FDG uptake demonstrated in our patient with benign pilomatricoma also suggests that FDG PET cannot reliably grade this rare condition.

  14. Sclerotherapy for Benign Cystic Diseases in the Neck

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hoon; Sohn, Chul Ho; Choi, Seung Hong; Yun, Tae Jin [Dept. of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2012-08-15

    Surgery has been the classic treatment of choice for benign cystic diseases, including lymphatic malformation, ranula, branchial cleft cyst, thyroglossal duct cyst, thyroid cyst, parathyroid cyst, and lymphocele. However, surgery is associated with a tendency toward recurrence and may be accompanied by various complications, such as nerve injuries, vascular injuries, and scar formation. Therefore, sclerotherapy using various agents has been applied successfully to treatment of benign cystic diseases in the neck. This editorial reviews the use of various sclerotic agents and application of sclerotherapy to benign cystic diseases in the neck.

  15. Indications for surgical resection of benign pancreatic tumors; Indikationen zur chirurgischen Therapie benigner Pankreastumoren

    Energy Technology Data Exchange (ETDEWEB)

    Isenmann, R.; Henne-Bruns, D. [Chirurgische Universitaetsklinik, Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie, Ulm (Germany)

    2008-08-15

    Benign pancreatic tumors should undergo surgical resection when they are symptomatic or - in the case of incidental discovery - bear malignant potential. This is the case for the majority of benign pancreatic tumors, especially for intraductal papillary mucinous neoplasms or mucinous cystic adenomas. In addition, resection is indicated for all tumors where preoperative diagnostic fails to provide an exact classification. Several different operative techniques are available. The treatment of choice depends on the localization of the tumor, its size and on whether there is evidence of malignant transformation. Partial duodenopancreatectomy is the oncological treatment of choice for tumors of the pancreatic head whereas for tumors of the pancreatic tail a left-sided pancreatectomy is appropriate. Middle pancreatectomy or duodenum-preserving resection of the pancreatic head is not a radical oncologic procedure. They should only be performed in cases of tumors without malignant potential. (orig.) [German] Die Indikationsstellung zur Resektion benigner Pankreastumoren ist gegeben, wenn es sich um einen symptomatischen Tumor handelt oder - bei einem Zufallsbefund - um einen Tumor mit Potenzial zur malignen Entartung. Dies besteht bei der Mehrzahl der benignen Pankreastumoren, insbesondere bei der intraduktalen papillaeren muzinoesen Neoplasie (IPMN) oder muzinoesen Zystadenomen. Operativer Abklaerung beduerfen auch Tumoren, die unter Ausschoepfung aller diagnostischer Moeglichkeiten nicht eindeutig klassifizierbar sind. An chirurgischen Therapieverfahren stehen verschiedene Techniken zur Verfuegung. Die Wahl des Verfahren haengt von der Groesse und Lokalisation des Tumors ab und von der Frage, ob eine maligne Entartung bereits stattgefunden hat. Das onkologisch korrekte Standardresektionsverfahren bei Tumoren des Pankreaskopfes ist die partielle Duodenopankreatektomie, bei Tumoren des Pankreasschwanzes die Pankreaslinksresektion. Eine segmentale Resektion des

  16. Numerical modelling of continuous spin detonation in rich methane-oxygen mixture

    Science.gov (United States)

    Trotsyuk, A. V.

    2016-10-01

    A numerical simulation of a two-dimensional structure of the detonation wave (DW) in a rich (equivalence ratio φ=1.5) methane-air mixture at normal initial condition has been conducted. The computations have been performed in a wide range of channel heights. From the analysis of the flow structure and the number of primary transverse waves in the channel, the dominant size of the detonation cell for studied mixture has been determined to be 45÷50 cm. Based on the fundamental studies of multi-front (cellular) structure of the classical propagating DW in methane mixtures, numerical simulation of continuous spin detonation (CSD) of rich (φ=1.2) methane-oxygen mixture has been carried out in the cylindrical detonation chamber (DC) of the rocket-type engine. We studied the global flow structure in DC, and the detailed structure of the front of the rotating DW. Integral characteristics of the detonation process - the distribution of average values of static and total pressure along the length of the DC, and the value of specific impulse have been obtained. The geometric limit of stable existence of CSD has been determined.

  17. Determination of minimum mass and spatial location of initiator for detonation of propylene oxide aerosols

    Science.gov (United States)

    Apparao, A.; Saji, J.; Balaji, M.; Devangan, A. K.; Rao, C. R.

    2017-03-01

    The mishandling of liquid fuels during production, processing or transportation can lead to the formation of combustible two-phase mixtures. These mixtures, with the availability of a suitable energy source, may be ignited generating a deflagration, or even a detonation wave. For military applications, unconfined fuel aerosols are created and detonated with the help of a strong shock generated by a powerful energy source. The minimum energy requirement is expressed in terms of the shock strength, or mass of the high-explosive-based initiator. In this study, the detonability of unconfined aerosols of 4.3 kg propylene oxide was studied by positioning different quantities of cylindrical-shaped initiators of RDX/wax (95/5) at a fixed spatial location in the aerosol cloud, and the minimum mass of the initiator required for detonation initiation was determined. The effect of spatial location and the requirement of initiator mass, especially at farther locations where the fuel concentration is likely to be lower and closer to the lower explosive limit, was also investigated. The experimental findings help identify the detonable zone in unconfined propylene oxide aerosol clouds for different combinations of spatial location and mass of initiator.

  18. Development of Detonation Modeling Capabilities for Rocket Test Facilities: Hydrogen-Oxygen-Nitrogen Mixtures

    Science.gov (United States)

    Allgood, Daniel C.

    2016-01-01

    The objective of the presented work was to develop validated computational fluid dynamics (CFD) based methodologies for predicting propellant detonations and their associated blast environments. Applications of interest were scenarios relevant to rocket propulsion test and launch facilities. All model development was conducted within the framework of the Loci/CHEM CFD tool due to its reliability and robustness in predicting high-speed combusting flow-fields associated with rocket engines and plumes. During the course of the project, verification and validation studies were completed for hydrogen-fueled detonation phenomena such as shock-induced combustion, confined detonation waves, vapor cloud explosions, and deflagration-to-detonation transition (DDT) processes. The DDT validation cases included predicting flame acceleration mechanisms associated with turbulent flame-jets and flow-obstacles. Excellent comparison between test data and model predictions were observed. The proposed CFD methodology was then successfully applied to model a detonation event that occurred during liquid oxygen/gaseous hydrogen rocket diffuser testing at NASA Stennis Space Center.

  19. Determination of minimum mass and spatial location of initiator for detonation of propylene oxide aerosols

    Science.gov (United States)

    Apparao, A.; Saji, J.; Balaji, M.; Devangan, A. K.; Rao, C. R.

    2016-06-01

    The mishandling of liquid fuels during production, processing or transportation can lead to the formation of combustible two-phase mixtures. These mixtures, with the availability of a suitable energy source, may be ignited generating a deflagration, or even a detonation wave. For military applications, unconfined fuel aerosols are created and detonated with the help of a strong shock generated by a powerful energy source. The minimum energy requirement is expressed in terms of the shock strength, or mass of the high-explosive-based initiator. In this study, the detonability of unconfined aerosols of 4.3 kg propylene oxide was studied by positioning different quantities of cylindrical-shaped initiators of RDX/wax (95/5) at a fixed spatial location in the aerosol cloud, and the minimum mass of the initiator required for detonation initiation was determined. The effect of spatial location and the requirement of initiator mass, especially at farther locations where the fuel concentration is likely to be lower and closer to the lower explosive limit, was also investigated. The experimental findings help identify the detonable zone in unconfined propylene oxide aerosol clouds for different combinations of spatial location and mass of initiator.

  20. Plasticity-dependent, full detonation at hippocampal mossy fiber–CA3 pyramidal neuron synapses

    Science.gov (United States)

    Vyleta, Nicholas P; Borges-Merjane, Carolina; Jonas, Peter

    2016-01-01

    Mossy fiber synapses on CA3 pyramidal cells are 'conditional detonators' that reliably discharge postsynaptic targets. The 'conditional' nature implies that burst activity in dentate gyrus granule cells is required for detonation. Whether single unitary excitatory postsynaptic potentials (EPSPs) trigger spikes in CA3 neurons remains unknown. Mossy fiber synapses exhibit both pronounced short-term facilitation and uniquely large post-tetanic potentiation (PTP). We tested whether PTP could convert mossy fiber synapses from subdetonator into detonator mode, using a recently developed method to selectively and noninvasively stimulate individual presynaptic terminals in rat brain slices. Unitary EPSPs failed to initiate a spike in CA3 neurons under control conditions, but reliably discharged them after induction of presynaptic short-term plasticity. Remarkably, PTP switched mossy fiber synapses into full detonators for tens of seconds. Plasticity-dependent detonation may be critical for efficient coding, storage, and recall of information in the granule cell–CA3 cell network. DOI: http://dx.doi.org/10.7554/eLife.17977.001 PMID:27780032

  1. Three-dimensional simulations of gravitationally confined detonations compared to observations of SN 1991T

    CERN Document Server

    Seitenzahl, Ivo R; Ohlmann, Sebastian T; Ciaraldi-Schoolmann, Franco; Marquardt, Kai; Fink, Michael; Hillebrandt, Wolfgang; Pakmor, Ruediger; Roepke, Friedrich K; Ruiter, Ashley J; Sim, Stuart A; Taubenberger, Stefan

    2016-01-01

    The gravitationally confined detonation (GCD) model has been proposed as a possible explosion mechanism for Type Ia supernovae in the single-degenerate evolution channel. Driven by buoyancy, a deflagration flame rises in a narrow cone towards the surface. For the most part, the flow of the expanding ashes remains radial, but upon reaching the outer, low-pressure layers of the white dwarf, an additional lateral component develops. This makes the deflagration ashes converge again at the opposite side, where the compression heats fuel and a detonation may be launched. To test the GCD explosion model, we perform a 3D simulation for a model with an ignition spot offset near the upper limit of what is still justifiable, 200 km. This simulation meets our deliberately optimistic detonation criteria and we initiate a detonation. The detonation burns through the white dwarf and leads to its complete disruption. We determine nucleosynthetic yields by post-processing 10^6 tracer particles with a 384 nuclide reaction netw...

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

    CERN Document Server

    Charignon, Camille

    2013-01-01

    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. Given a large enough jump in density a small pressure and velocity perturbation, produced by the turbulent deflagration, turns into a shock down of the gradient, where it will dissipate and heat up the media. With the right frequency and amplitude the heating can be enough to initiate a detonation, which can propagate backward and up the density gradient. We studied planar and spherical geometry. In the planar case we made a parametric study of the frequency and amplitude. We found it possible to obtain a detonation for perturbations down to Mach number M=0.003. In the spherical case, geometrical damping makes it harder to initiate a detonation, but considering a small He atmosphere (<0.01 Msol) makes it possible again to obtain a detonation down to small perturbation (M=0.002). In ...

  3. Study of detonation initiation in kerosene-oxidizer mixtures in short tubes

    Science.gov (United States)

    Kindracki, J.

    2014-11-01

    The paper describes experimental studies of detonation initiation in a kerosene-oxidizer mixture in a short test tube. The aim of the study is to determine the minimum diameter of the tube and the minimum level of energy that enables direct initiation of the detonation. Knowledge about these values will inform the design of a jet engine combustion chamber in which thermal energy will be generated by a rotating detonation process. The test tube and the oxidizer inside the tube were heated using specially designed heaters installed outside of the tube. The heated oxidizer provided thermal conditions similar to the conditions for a compressor with small to medium static pressure. The study was conducted for four different tube diameters and for various energies of initiation. As a result, measurements of pressure waveforms were obtained for various cases of fuel injection, which were then compared against the results of the shock wave generated by the initiator. This study provides a value for the energy (the pressure of the mixture in the initiator), which provided direct initiation of detonation for a kerosene-oxidizer mixture. Different tube diameters led to the initiation of detonation for various oxygen-nitrogen compositions as an oxidizer.

  4. Experimental Investigation on Heating Kerosene Using Thrust Tube Waste Heat of Pulse Detonation Engine

    Science.gov (United States)

    Huang, Xiqiao; Yan, Yu; Mu, Yang; Zheng, Longxi; Chen, Le

    2013-12-01

    Performance of liquid hydrocarbon fueled pulse detonation engines are hindered by the time required to evaporate liquid fuel droplets within the mixture. Efforts such as heating the liquid fuel before introduced into the engine were made to overcome this problem. The engine wall suffered high temperature of gaseous detonative products, which is harmful to the engine. Therefore the waste heat of PDE engine wall was used here to heat the liquid kerosene of the engine by using two concentric heat-exchangers with helical slot inside mounted at the tail of the pulse detonation engine. The pulse detonation engine (PDE) used here are 110 mm in inner diameter and 1700 mm in length and liquid kerosene and gaseous air were used as fuel and oxidizer respectively. Heating liquid kerosene was found effective in enhancing the engine performance, which was helpful for deflagration to detonation transition process. It was found that the waste heat could elevate the kerosene temperature effectively and the wall temperature could also be decreased obviously.

  5. Impact of radiation therapy for benign diseases; Role de la radiotherapie dans les affections benignes

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, G. [Institut National de la Sante et de la Recherche Medicale (INSERM), Fondation Bergonie, 33 - Bordeaux (France); Van Houtte, P.; Beauvois, S.; Roelandts, M. [Institut Bordet, Brussels (Belgium)

    1997-12-31

    Radiation therapy of benign diseases represent a wide panel of indications. Some indications are clearly identified as treatment of arteriovenous malformations (AVM), hyperthyroid ophthalmopathy, postoperative heterotopic bone formations or keloid scars. Some indications are under evaluation as complications induced by neo-vessels of age-related macular degeneration or coronary restenosis after angioplasty. Some indications remain controversial with poor evidence of efficiency as treatment of bursitis, tendinitis or Dupuytren`s disease. Some indications are now obsolete such as warts, or contra-indicated as treatment of infant and children. (authors)

  6. Experimental observations of detonation in ammonium-nitrate-fuel-oil (ANFO) surrounded by a high-sound speed, shockless, aluminum confiner

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Scott I [Los Alamos National Laboratory; Klyanda, Charles B [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory

    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 desensitize the explosive by crushing porosity required for shock initiation or destroying confinement ahead of the detonation. As these phenomena are not well understood, most numerical explosive models are unable to account for them. 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 an aluminum confining tube. Detonation velocity, detonation front curvature, and aluminum response are recorded as a function of confiner wall thickness and length. Front curvature profiles display detonation acceleration 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 due to the additional inertial confinement of the reaction zone flow. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected which interfered with the front curvature 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.

  7. VIDEOLARYNGOSCOPIC SURGEY IN BENIGN LARYNGEAL LESIONS-OUR EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Satheesh

    2015-11-01

    Full Text Available : Benign laryngeal lesions are commonly encountered causes of dysphonia and are often surgically correctable. A prospective study on 62 cases selected for videolaryngoscopic surgery was undertaken in a single unit in the department of ENT, Medical College Hospital, Thiruvananthapuram. The male: female ratio was 1.8:1 and the most common affected age group was 35-45 yrs. The most common benign lesion was vocal polyp. Preoperative voice assessment and 70 degree endoscopy was done. Follow up visits were done at 1 week, 3 weeks and 6 weeks and voice assessment and laryngoscopic appearances were noted. 98% reported excellent improvement of voice. The varieties of benign lesions which cause hoarseness are sources of concern and worry as it can affect the self esteem of a person. Thus videolaryngoscopic surgery (VLS coupled with voice therapy offers cost effective and safe management in benign laryngeal lesions

  8. Environmentally Benign Tribo-systems for Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Azushima, A.; Groche, P.

    2010-01-01

    The growing awareness of environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has initiated ever increasing efforts to develop new, environmentally benign tribological systems for metal forming. The present ...

  9. Therapy: a new nonsurgical therapy option for benign thyroid nodules?

    DEFF Research Database (Denmark)

    Hegedüs, Laszlo

    2009-01-01

    Despite the increasing implementation of iodization programs, benign nodular thyroid disease will remain a prevalent therapeutic concern for decades. recent research suggests that nonsurgical therapy, including radioactive iodine, radiofrequency thermal ablation and percutaneous laser ablation...

  10. Stroboscopy for benign laryngeal pathology in evidence based health care

    OpenAIRE

    Printza, A; Triaridis, S; Themelis, C; Constantinidis, J

    2012-01-01

    Background and Aims: Voice disorders are common. The aim of this study is to evaluate the diagnostic value of stroboscopy for voice disorders related with benign pathology and apply results in evidence based health care.

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

    Science.gov (United States)

    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.

  12. Constraints On The Delayed Transition to Detonation in Type Ia Supernovae

    CERN Document Server

    Lisewski, A M; Woosley, S E

    1999-01-01

    We investigate the possibility of a delayed detonation scenario within a type Ia supernova in a case where the transition to detonation is assumed to be triggered by turbulence only. Our results are based on the Zeldovich mechanism and suggest that typical turbulent velocities present during the explosion are not strong enough to allow this transition. Although we are able to show that carbon-rich matter (e.g. $X(^{12}$C$) = 0.75$) significantly enhances the possibility of a deflagration to detonation transition (DDT), it turns out that even in this case the necessary turbulent velocities are larger than the expected vlaue of $u'(L) \\approx 10^7 {cm s}^{-1}$ on a length-scale of $L a thermonuclear explosion of a chandrasekhar-mass white dwarf.

  13. Detonative Propagation and Accelerative Expansion of the Crab Nebula Shock Front

    CERN Document Server

    Gao, Yang

    2011-01-01

    The accelerative expansion of the Crab nebula's outer envelope is a mystery in dynamics as a conventional expanding blast wave decelerates when bumping into the surrounding interstellar medium. Here we show that the strong relativistic pulsar wind bumping into its surrounding nebula induces energy-generating processes and initiates a detonation wave that propagates outward to form the current outer edge, namely the shock front, of the nebula. The resulting detonation wave, with a reactive downstream, then provides the needed power to maintain propagation of the shock front. Furthermore, relaxation of the curvature-induced reduction of the propagation velocity from the initial state of formation to the asymptotic, planar state of Chapman-Jouguet propagation explains the observed accelerative expansion. The essential role of detonative propagation in the structure and dynamics of the Crab nebula offers potential richness in incorporating reactive fronts in the description of various astronomical phenomena.

  14. The effect of initial pressure on detonation propagation across a mixture

    Directory of Open Access Journals (Sweden)

    Yao-Chung Hsu

    2016-07-01

    Full Text Available This study determines the effect of the initial pressure on the propagation of a Chapman–Jouguet detonation wave from a stoichiometric C3H8/O2 mixture (donor to a stoichiometric C3H8/air mixture (acceptor. Depending on the initial pressure ratio in the donor and the acceptor, the result can be a smooth transmission, a re-initiated detonation wave, or a transmitted shock wave. When the donor is divided into a driver donor and a driven donor, the degree of overdrive in a driven donor varies with the donor pressure ratio. There must be a greater degree of overdrive in the driven donor for re-initiation of a detonation wave in the acceptor, particularly if the initial pressure in the driven donor is lower than the Chapman–Jouguet pressure in the acceptor. The bi-dimensional effect is also another major factor.

  15. Beyond the bubble catastrophe of Type Ia supernovae: Pulsating Reverse Detonation models

    CERN Document Server

    Bravo, E; Bravo, Eduardo; Garcia-Senz, Domingo

    2006-01-01

    We describe a mechanism by which a failed deflagration of a Chandrasekhar-mass carbon-oxygen white dwarf can turn into a successful thermonuclear supernova explosion, without invoking an ad hoc high-density deflagration-detonation transition. Following a pulsating phase, an accretion shock develops above a core of 1 M_sun composed of carbon and oxygen, inducing a converging detonation. A three-dimensional simulation of the explosion produced a kinetic energy of 1.05E51 ergs and 0.70 M_sun of 56Ni, ejecting scarcely 0.01 M_sun of C-O moving at low velocities. The mechanism works under quite general conditions and is flexible enough to account for the diversity of normal Type Ia supernovae. In given conditions the detonation might not occur, which would reflect in peculiar signatures in the gamma and UV-wavelengths

  16. Reliable prediction of electric spark sensitivity of nitramines: a general correlation with detonation pressure.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein; Pouretedal, Hamid Reza; Semnani, Abolfazl

    2009-08-15

    For nitramines, a general correlation has been introduced to predict electric spark sensitivity through detonation pressure. New method uses maximum obtainable detonation pressure as a fundamental relation so that it can be corrected for some nitramines which have some specific molecular structure. There is no need to use crystal density and heat of formation of nitramine explosives for predicting detonation pressure and electric spark sensitivity. The predicted electric spark sensitivities are compared with calculated results on the basis of quantum mechanical computations for some nitramines that latter can be applied. The root mean square (rms) deviations from experiment for new method and the predicted results of complicated quantum mechanical method are 1.18 and 3.49J, respectively.

  17. Determining heats of detonation of non-aromatic energetic compounds without considering their heats of formation.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2007-04-02

    A new procedure is introduced for calculating heats of detonation of non-aromatic energetic compounds through ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some structural parameters. There is no need to use heats of formation of non-aromatic energetic compounds that are usually needed by the other methods. Moreover, this much simple method does not use any experimental and computed data of energetic materials. Predicted heats of detonation for 28 non-aromatic energetic compounds have a root mean square (rms) of deviation of 0.54 kJ/g from experiment, which show good agreement with respect to measured values. The new method is the simplest procedure for predicting heats of detonation and provides reliable results which are comparable with the other methods.

  18. Simulative Calculation of Mechanical Property, Binding Energy and Detonation Property of TATB/Fluorine-polymer PBX

    Institute of Scientific and Technical Information of China (English)

    MA, Xiu-Fang; XIAO, Ji-Jun; HUANG, Hui; JU, Xue-Hai; LI, Jin-Shan; XIAO, He-Ming

    2006-01-01

    Molecular dynamics (MD) method was used to simulate 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB>TATB/PVDF>TATB/F2311 >TATB/F2314>TATB/PCTFE while the order of detonation velocity is TATB/PVDF<TATB/F2311 <TATB/F2314<TATB/PCTFE<TATB.

  19. Critical Shock Energy and Shock and Detonation Parameters of an Explosive

    Directory of Open Access Journals (Sweden)

    H. S. Yadav

    2009-07-01

    Full Text Available The present study deals with the connection between critical shock energy and detonation properties of an explosive. A relation for critical shock energy has been derived in terms of detonation velocity, width of reaction zone, initial density of the explosive, specific heat ratio of detonation products and either constants of linear relation between shock and particle velocity of the explosive or the constants of the Murnaghan’s type of equation of state of the explosive. These relations have been used to calculate the critical shock energy of RDX, HMX, RDX/TNT (60/40 and TNT explosives. The values of critical shock energies obtained in this study are in close agreement with those reported in the literature.Defence Science Journal, 2009, 59(4, pp.436-440, DOI:http://dx.doi.org/10.14429/dsj.59.1543

  20. Deflagration-to-detonation transition project. Quarterly report, December 1979-February 1980

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, M.L. (ed.)

    1980-09-01

    Progress in a project on deflagration-to-detonation transition (DDT) is reported. The activities of this project pertain primarily to the development of small, safe, low-voltage, hot-wire detonators. Its major goals are: the formulation of a modeling capability for DDT of the explosive 2-(5-cyanotetrazolato)pentaamminecobalt (III) perchlorate (CP); the development of improved DDT materials; the establishment of a data base for corrosion, compatibility, and reliability of CP-loaded detonators; and the design and development of advanced DDT components. Information is included on materials development, component development, and compatibility studies encompassing the thermal and chemical stability of CP in contact with the component materials. (LCL)