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

    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

  3. Environmentally Benign Stab Detonators

    Science.gov (United States)

    2006-07-11

    Steve Santor, Mr. Phil Ramsey , and Mr. Octavio Cervantes. Contributors from TACOM-ARDEC include Mr. Gartung Cheng, and Mrs. Neha Mehta...obtain more reproducible stab initiation results led to size sorting of the sheared material. This was performed using a series of Tyler U.S. standard... Tyler Standard 50 Mesh sieve (particle size range is 300 µm to 500 µm) Sample Thickness (um) Bi-layer Period (nm) Coating Min. Stab energy (mJ

  4. Pressure-balanced stab connection

    Energy Technology Data Exchange (ETDEWEB)

    Best, M.J.A.; Jones, R.H.; Hynes, J.H.; Pond, R.J.; Gordon, C.R.

    1987-09-22

    This patent describes an apparatus for sealingly connecting a flow bore of a wellhead to a flowline. It consists of: a stab member including a stab body. The stab body has a stab body bore. One end of the stab body bore exiting from the stab body and being in fluid communication with the flow bore and the other end of the stab body bore exiting from a side of the stab body through a stab body side port; a stab receptacle mounted on the wellhead and having a stab receiving bore for receiving the stab body; the stab receptacle having a receptacle flow bore. One end of the receptacle flow bore being in fluid communication with the stab receiving bore and the other end of the receptacle flow bore exiting the stab receptacle and being in fluid communication with the flowline; means for establishing fluid communication between the stab body side port and the one end of the receptacle flow bore when the stab body is received within the stab receiving bore. It includes means disposed on the stab member for orienting the stab member with respect to the Christmas tree for ensuring the alignment of the stab body side port with the one end of the receptable flow bore when the stab body is received within the stab receiving bore; and first and second sealing means disposed on the stab body above and below the stab body side port, respectively, for sealing engagement with the walls of the stab receiving bore above and below the one end of the receptable flow bore for establishing a non-blow-apart, fluid pressure sealed flow passage between the stab body bore of the stab member and the receptacle flow bore of the stab receptacle when the stab body is landed within the stab receiving bore.

  5. Stab resistant body armour

    OpenAIRE

    Horsfall, I

    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...

  6. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Thermonuclear detonation

    International Nuclear Information System (INIS)

    Feoktistov, L.P.

    1998-01-01

    The characteristics of, and energy transfer mechanisms involved in, thermonuclear detonation are discussed. What makes the fundamental difference between thermonuclear and chemical detonation is that the former has a high specific energy release and can therefore be employed for preliminary compressing the thermonuclear mixture ahead of the burning wave. Consequently, with moderate (mega joule) initiation energies, a steady-state detonation laboratory experiment with unlimited energy multiplication becomes a possibility

  8. Thermonuclear detonation

    International Nuclear Information System (INIS)

    Feoktistov, L P

    1998-01-01

    The characteristics of, and energy transfer mechanisms involved in, thermonuclear detonation are discussed. What makes the fundamental difference between thermonuclear and chemical detonation is that the former has a high specific energy release and can therefore be employed for preliminarily compressing the thermonuclear mixture ahead of the burning wave. Consequently, with moderate (megajoule) initiation energies, a steady-state detonation laboratory experiment with unlimited energy multiplication becomes a possibility. (from the history of physics)

  9. Textile sensors for stab and cut detection

    Science.gov (United States)

    Graßmann, C.; Obermann, M.; Lempa, E.; Bache, T.; Siegel, P. K.; Freyer, T.; Paschko, S.; Beyer, T.; Kirsche, M.; Schwarz-Pfeiffer, A.

    2017-10-01

    Manufacturers are aiming for more flexible and lightweight protective clothing to increase wearing comfort. A cardigan with a knitted stab-resistant inlay and an alarm system is presented. The stab-resistant inlay is based on a multilayer ultra-high molecular weight poly ethylene (UHMW-PE) fabric. Stab resistance was evaluated according to the standard of the Association of Test Laboratories for Bullet, Stab or Pike Resistant Materials and Construction Standard (VPAM 2011). Furthermore sensors for the detection of cuts and pressure were integrated. Both sensors can trigger alarms if the wearer is attacked. Normal pressure occurring through leaning on a wall or sitting is filtered out and does not trigger an alarm.

  10. The imaging of stab injuries

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Coert S. de; Africa, Mogoeemang; Gebremariam, Fekade A.; Rensburg, J. Janse van; Otto, Susan F.; Potgieter, Henrik F. (Dept. of Diagnostic Radiology, Faculty of Health Sciences, Univ. of the Free State and Academic Health Complex, Free State Province Dept. of Health, Bloemfontein (South Africa)), e-mail: devriesc.md@ufs.ac.za

    2010-01-15

    In the trauma unit of the Bloemfontein Academic Complex, the total number of stab wounds seen represents approximately 70.5% of penetrating injuries, which is 6.4% of 5004 trauma cases seen in a period of 1 year. The other cases are gunshot wounds and pedestrian or motor vehicle accidents. Specific guidelines and protocols are followed for penetrating trauma management. All imaging modalities are utilized, with chest radiography the mainstay of thoracic imaging in patients having sustained sharp penetrating chest injuries. Computed tomography (CT) is being used more frequently as the primary imaging modality in the evaluation of hemodynamically stable patients with penetrating injuries. The improved speed of data acquisition and superior image reconstruction of multidetector CT (MDCT) has further driven this change in imaging approach. Although digital subtraction angiography (DSA) has been the reference standard for the diagnosis of traumatic vascular injuries, it is giving way to faster, less invasive, and less personnel-intensive imaging techniques, e.g., MDCT angiography. Given the fact that we work in an academic environment and that we have a dedicated interventional unit, arteriography is still frequently performed and still has its place as the 'gold standard' in the diagnosis of vascular injuries. Penetrating chest injuries suspected of traversing the mediastinum or extending near the posterior mediastinal structures dictate esophageal and tracheal evaluation. Although radiology has a role to play, direct visualization (esophagoscopy, bronchoscopy) remains the most reliable method of excluding injuries to these structures. Transthoracic ultrasound (echocardiography) has become indispensable in helping to evaluate injuries to the heart and the ascending and descending aortas. More recent work has demonstrated that ultrasonography can also be used to detect hemothoraces and pneumothoraces with accuracy

  11. Confined Detonations and Pulse Detonation Engines

    National Research Council Canada - National Science Library

    Roy, Gabriel D; Frolov, Sergi M; Santoro, Robert J; Tsyganov, Sergei A

    2003-01-01

    .... Contrary to the oblique-detonation concept that is applicable to hypersonic flight at velocities comparable or higher than the Chapman-Jouguet detonation velocity of the fuel-air mixture, the concept...

  12. 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.

  13. 76 FR 69764 - Stab-Resistant Body Armor Standard Workshop

    Science.gov (United States)

    2011-11-09

    ... of Justice Programs Stab-Resistant Body Armor Standard Workshop AGENCY: National Institute of Justice... Standards and Technology (NIST) are jointly hosting a workshop focused on the NIJ Stab-resistant Body Armor... the revised NIJ Stab-resistant Body Armor Standard and to receive input, comments, and recommendations...

  14. 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.

  15. 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...

  16. 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.  .

  17. Towards Detonation Theory

    OpenAIRE

    Dremin, A.

    1995-01-01

    Experimental findings inconsistent with both the CJ and the ZND detonation theories are discussed. These are the unstable detonation and the weak dependence on charge diameter of liquid explosives detonation velocity at sizable value of their failure diameter. The investigations have resulted in the discovery and introduction into detonation theory of two new theoretical notions : chemical reaction breakdown (BD) and shock discontinuity zone (SDZ). It is shown that the BD governs the limits o...

  18. Detonation Wave Profile

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Laboratory

    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.

  19. Herpes simplex virus following stab phlebectomy.

    Science.gov (United States)

    Hicks, Caitlin W; Lum, Ying Wei; Heller, Jennifer A

    2017-03-01

    Herpes simplex virus infection following surgery is an unusual postoperative phenomenon. Many mechanisms have been suggested, with the most likely explanation related to latent virus reactivation due to a proinflammatory response in the setting of local trauma. Here, we present a case of herpes simplex virus reactivation in an immunocompetent female following a conventional right lower extremity stab phlebectomy. Salient clinical and physical examination findings are described, and management strategies for herpes simplex virus reactivation are outlined. This is the first known case report of herpes simplex virus reactivation following lower extremity phlebectomy.

  20. Unusual Presentation of Meningitis following Stab Neck | Motsitsi ...

    African Journals Online (AJOL)

    Background: A case report of stab neck presenting at Kalafong Hospital, Pretoria, South Africa with atypical meningitis. The objective was to illustrate the challenge of diagnosing this unusual and late presentation of meningitis. Case Report: A 48 year-old male patient presented to us two days after a stab neck. He was ...

  1. Detonation command and control

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-12-05

    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.

  2. Conservative treatment of abdominal stab wounds with omental protrusion

    DEFF Research Database (Denmark)

    Duus, B R; Damm, P; Jensen, F U

    1987-01-01

    Two cases of abdominal stab wounds with omental protrusion treated conservatively are presented. Omental protrusion in a patient without signs of shock or peritoneal irritation is not an absolute indication for explorative laparotomy.......Two cases of abdominal stab wounds with omental protrusion treated conservatively are presented. Omental protrusion in a patient without signs of shock or peritoneal irritation is not an absolute indication for explorative laparotomy....

  3. Characteristics and rehabilitation for patients with spinal cord stab injury

    Science.gov (United States)

    Wang, Fangyong; Zhang, Junwei; Tang, Hehu; Li, Xiang; Jiang, Shudong; Lv, Zhen; Liu, Shujia; Chen, Shizheng; Liu, Jiesheng; Hong, Yi

    2015-01-01

    [Purpose] The objective of the study was to compare the incidence, diagnosis, treatment, and prognosis of patients with spinal cord stab injury to those with the more common spinal cord contusion injury. [Subjects] Of patients hospitalized in China Rehabilitation Research Center from 1994 to 2014, 40 of those having a spinal cord stab injury and 50 with spinal cord contusion were selected. [Methods] The data of all patients were analyzed retrospectively. The cases were evaluated by collecting admission and discharge ASIA (American Spinal Injury Association) and ADL (activity of daily living) scores. [Results] After a comprehensive rehabilitation program, ASIA and ADL scores of patients having both spinal cord stab injury and spinal cord contusion significantly increase. However, the increases were noted to be higher in patients having a spinal cord stab injury than those having spinal cord contusion. [Conclusion] Comprehensive rehabilitation is effective both for patients having spinal cord stab injury and those with spinal cord contusion injury. However, the prognosis of patients having spinal cord stab injury is better than that of patients with spinal cord contusion. PMID:26834329

  4. Selective Nonoperative Management of Abdominal Stab Wounds.

    Science.gov (United States)

    Murry, Jason S; Hoang, David M; Ashragian, Sogol; Liou, Doug Z; Barmparas, Galinos; Chung, Rex; Alban, Rodrigo F; Margulies, Daniel R; Ley, Eric J

    2015-10-01

    Stab wounds (SW) to the abdomen traditionally require urgent exploration when associated with shock, evisceration, or peritonitis. Hemodynamically stable patients without evisceration may benefit from serial exams even with peritonitis. We compared patients taken directly to the operating room with abdominal SWs (ED-OR) to those admitted for serial exams (ADMIT). We retrospectively reviewed hemodynamically stable patients presenting with any abdominal SW between January 2000 and December 2012. Exclusions included evidence of evisceration, systolic blood pressure ≤110 mm Hg, or blood transfusion. NON-THER was defined as abdominal exploration without identification of intra-abdominal injury requiring repair. Of 142 patients included, 104 were ED-OR and 38 were ADMIT. When ED-OR was compared with ADMIT, abdominal Abbreviated Injury Score was higher (2.4 vs 2.1; P = 0.01) and hospital length of stay was longer (4.8 vs 3.3 days; P = 0.04). Incidence of NON-THER was higher in ED-OR cohort (71% vs 13%; P ≤ 0.001). In a regression model, ED-OR was a predictor of NON-THER (adjusted odds ratio 16.6; P patient from ED-OR expired after complications from NON-THER. There were no deaths in the ADMIT group. For those patients with abdominal SWs who present with systolic blood pressure ≥110 mm Hg, no blood product transfusion in the emergency department and lacking evisceration, admission for serial abdominal exams may be preferred regardless of abdominal exam.

  5. Primary stabbing headache in adults and pediatrics: a review.

    Science.gov (United States)

    Hagler, Suzanne; Ballaban-Gil, Karen; Robbins, Matthew S

    2014-10-01

    Primary stabbing headache (PSH) is an under-recognized primary headache disorder, which often goes undiagnosed. It is mainly characterized by its ultrashort stabbing quality and can be easily overlooked both by patients and providers as it is often not severe enough to interfere significantly with daily life. However, PSH may be severe and require therapy, and it is important for providers to recognize this headache type, both in adult and pediatric populations, as well as to be able to distinguish it from secondary headache disorders. PSH also may be more common than previously thought.

  6. The correlation between stabbing-related upper extremity wounds and survival of stabbing victims with abdominal and thoracic injuries.

    Science.gov (United States)

    Rozenfeld, Michael; Peleg, Kobi; Givon, Adi; Kessel, Boris

    2017-07-01

    When treating patients with stab injuries of the torso, clinicians often lack timely information about the degree and nature of internal organ damage. An externally observable sign significantly associated with characteristics of torso injuries may therefore be useful for practitioners. One such potential sign is the presence of wounds to the hands, sometimes sustained during victims' attempt to defend themselves during the violent altercation. Thus, the primary aim of this study was to evaluate the association between presence of upper extremity wounds and the severity of the thoracic and intra-abdominal injuries due to stabbing. This study was carried out retrospectively using data on 8714 patients with stabbing-related injuries from 19 trauma centers that participated in the Israeli National Trauma Registry (INTR) between January 1st1997 and December 31st 2013. Patients with wounds of upper extremities in addition to torso injuries (UE group) were compared to other patients with torso injuries (TO group) in terms of demographics, injury characteristics and clinical outcome. The compared groups were found to be homogeneous in terms of age and systolic blood pressure; the number of sustained torso injuries was also identical. The UE group comprised a slightly greater percentage of females, however both groups were predominantly male. Patients with upper extremity injuries had a lower proportion of internal organ damage (36% vs. 38.5%) and lower mortality (0.9% vs. 2%). The higher mortality of patients without upper extremity wounds remained significantly different even when adjusted by other epidemiological parameters (OR 2.46, 95% CI 1.33-5.08).The number of sustained upper extremity injuries was positively associated with deeper penetration of the torso by the stabbing instrument. Patients with stabbing-related upper extremity wounds had a significant survival advantage over patients without such injuries. However, a greater number of sustained upper extremity

  7. Clamp for detonating fuze

    Science.gov (United States)

    Holderman, E. J.

    1968-01-01

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

  8. Scientific Letter: Stabbing nails into the neck: an unusual self ...

    African Journals Online (AJOL)

    Scientific Letter: Stabbing nails into the neck: an unusual self-damaging behavior mandating neurosurgery. A Aghabiklooei, R Aghabiklooei, N Zamani. Abstract. Scientific Letter - No Abstract Available. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  9. 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...

  10. Non-operative management of abdominal stab wounds -an analysis ...

    African Journals Online (AJOL)

    Patients with abdominal stab wounds presenting with peritonitis, haemodynamic instability, organ evisceration and high spinal cord injury underwent emergency laparotomy. No local wound exploration, diagnostic peritoneal lavage or ultrasound was used. Haematuria in patients without an indication for emergency surgery ...

  11. 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…

  12. Suppression of sympathetic detonation

    Science.gov (United States)

    Foster, J. C., Jr.; Gunger, M. E.; Craig, B. G.; Parsons, G. H.

    1984-08-01

    There are two basic approaches to suppression of sympathetic detonation. Minimizing the shock sensitivity of the explosive to long duration pressure will obviously reduce interround separation distances. However, given that the explosive sensitivity is fixed, then much can be gained through the use of simple barriers placed between the rounds. Researchers devised calculational methods for predicting shock transmission; experimental methods have been developed to characterize explosive shock sensitivity and observe the response of acceptors to barriers. It was shown that both EAK and tritonal can be initiated to detonation with relatively low pressure shocks of long durations. It was also shown that to be an effective barrier between the donor and acceptor, the material must attenuate shock and defect fragments. Future actions will concentrate on refining the design of barriers to minimize weight, volume, and cost.

  13. Abdominal and lower back pain in pediatric idiopathic stabbing headache.

    Science.gov (United States)

    Kakisaka, Yosuke; Ohara, Tomoichiro; Hino-Fukuyo, Naomi; Uematsu, Mitsugu; Kure, Shigeo

    2014-01-01

    Idiopathic stabbing headache (ISH) is a primary headache syndrome characterized by transient, sharp, stabbing pains located in the first division of the trigeminal nerve. Reports of pediatric ISH are rare, and extracephalic pain in pediatric ISH is extremely rare. Here we report the case of a 7-year-old male patient suffering from frequent, short, stabbing headache, which was occasionally associated with abdominal and lower back pain. Various investigations were normal. He was diagnosed with ISH, and valproic acid was administered to relieve his headache and accompanying symptoms. Our case demonstrates that abdominal and lower back pain may occur in pediatric ISH. This case may provide new evidence linking ISH and migraine by showing that extracephalic symptoms accompanying ISH are similar to those of migraine. We hypothesize that the mechanism underlying the headache and abdominal and lower back pain associated with ISH may be similar to that of a migraine headache. Accumulating additional cases by asking specific questions regarding the presence of the unusual symptoms presented in our case may help to establish a detailed clinical profile of these unfamiliar and peculiar symptoms in the pediatric ISH population.

  14. Benign positional vertigo

    Science.gov (United States)

    Vertigo - positional; Benign paroxysmal positional vertigo; BPPV: dizziness- positional ... Benign positional vertigo is also called benign paroxysmal ... ear has fluid-filled tubes called semicircular canals. When you ...

  15. Novel Uses of Detonator Diagnostics

    Science.gov (United States)

    Gibson, John

    2017-06-01

    A novel combination of diagnostics is being used to research the physics of detonator initiation. Rogowski coils are being used to obtain the time derivatives of electrical currents in the detonators in combination with polyvinylidene difluoride (PVDF) stress sensors to monitor shock propagation. PVDF is commonly used in contact with the detonator output to detect breakout time of the detonation wave; however, in this experiment PVDF foils are separated from the PETN and re-oriented to observe various shock events from the time of bridge burst until the breakout time of the detonation wave. The goal of these experiments is to use these diagnostics to study the response of detonators using specific explosive particle sizes. The new diagnostics were used to determine the timing of bridge burst, flyer impact, wave propagation and detonator breakout. Custom designed fixtures were loaded with the explosive PETN, which was pressed to a density of 1.55 g/cc. The results of testing various detonators with these new techniques will be presented. The data are compared to those of currently used diagnostics in order to validate the accuracy of these new methods. Future experiments will incorporate other methods of validation including dynamic radiography.

  16. Terrorist Stabbings-Distinctive Characteristics and How to Prepare for Them.

    Science.gov (United States)

    Merin, Ofer; Sonkin, Roman; Yitzhak, Avraham; Frenkel, Hagai; Leiba, Adi; Schwarz, Alon D; Jaffe, Eli

    2017-10-01

    The number of terror attack incidents is on the increase worldwide. The knife is one of the weapons most commonly used among terrorists. Appropriate preparation in trauma units for coping with the increasing numbers of terrorist-inflicted stabbings is different from the preparation suitable for civilian stabbings. Therapeutic and logistic guidelines need to be adjusted to accommodate those differences. Characterize the unique injuries related to terrorist stabbing, and suggest preparedness actions. Retrospective data on all terrorist-inflicted stabbing incidents between September 2015 and May 2016 were retrieved from the database of the national Israeli emergency medical services and from the Israeli Defense Forces Medical Corps records. There were a total of 414 civilian victims (34 fatalities) of terror incidents. Of these, 161 involved stabbings during 106 separate incidents. There was more than 1 stab wound per patient in approximately 60% of cases, and more than 1 victim in approximately 40% of cases. Unlike civilian stabbings, terrorist stabbings were characterized by more commonly occurring to the upper part of the body, being executed by large knives with high force, and involving multiple and more severe injuries. There is a clear distinction between the characteristics of wounds resulting from civilian stabbings and those incurred by acts of terror. Terrorists intend to injure as many random victims as possible, and trauma units need to be prepared to cope with the simultaneous admission of multiple patients with penetrating and often life-threatening knife wounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Planar Reflection of Gaseous Detonations

    Science.gov (United States)

    Damazo, Jason Scott

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

  18. Forensic evidence in apparel fabrics due to stab events.

    Science.gov (United States)

    Kemp, S E; Carr, D J; Kieser, J; Niven, B E; Taylor, M C

    2009-10-30

    Stab injuries and fatalities have been reported to be the most common crimes of violence in several countries, particularly in those where access to firearms is restricted [J.M. Taupin, F.-P. Adolf, J. Robertson, Examination of damage to textiles, in: J. Robertson, M. Grieve (Eds.), Forensic Examination of Fibres, CRC Press, United States of America, 1999, pp. 65-87; A.C. Hunt, R.J. Cowling, Murder by stabbing, Forensic Sci. Int. 52 (1991) 107-112; D.A. Rouse, Patterns of stab wounds: a six year study, Med. Sci. Law 34 (1994) 67-71]. Analysis of damaged apparel may provide important information about the cause of death and the events leading up to and after the victim's final moments [M.T. Pailthorpe, N.A.G. Johnson, The private forensic scientist and the criminal justice system, in: D. Biles, J. Vernon (Eds.), Private Sector and Community Involvement in the Criminal Justice System: Conference Proceedings, vol. 23, Australian Institute of Criminology, Wellington, 1994, 231-240]. A high proportion of stab wounds occur in the chest and as this area is generally clothed many sharp force cases involve damage to fabrics [J.M. Taupin, F.-P. Adolf, J. Robertson, Examination of damage to textiles, in: J. Robertson, M. Grieve (Eds.), Forensic Examination of Fibres, CRC Press, United States of America, 1999, pp. 65-87; A.C. Hunt, R.J. Cowling, Murder by stabbing, Forensic Sci. Int. 52 (1991) 107-112; D.A. Rouse, Patterns of stab wounds: a six year study, Med. Sci. Law 34 (1994) 67-71]. The structural stabilisation and degradation of fabric due to laundering significantly alters fabric properties [S.E. Gore, R.M. Laing, C.A. Wilson, D.J. Carr, B.E. Niven, Standardizing a pre-treatment cleaning procedure and effects of application on apparel fabrics, Text. Res. J. 76 (2006) 455-464], yet the effect of such on severance morphology does not appear to have been investigated. In this work the effect of blade type (hunting knife, kitchen knife, screwdriver) on new and laundered

  19. Detonation spreading in fine TATBs

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  20. 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.

  1. Detonation Propagation Through Ducts in a Pulsed Detonation Engine

    Science.gov (United States)

    2011-03-01

    Collin, Adam, Mike, Bob , Jared, Josh, you guys are awesome! Jeff Nielsen vi Table of Contents Page Abstract...pp. 375-381. 9. Feivisohn, Robert T. Numerical Investigation of Pre-detonator Geometries for PDE Applications. MS thesis, AFIT/GAE/ENY/10-M09... Berman , M. Hydrogen-Air Detonations, 19th Symposium (Int.) on Combustion, pp. 583-590, 1982. 16. Knystautas, R., Guirao, C., Lee, J.H., and

  2. The application of PA/CF in stab resistance body armor

    Science.gov (United States)

    Yuan, M. Q.; Liu, Y.; Gong, Z.; Qian, X. M.

    2017-06-01

    Stab resistance body armor (SRBA) is an essential defensive equipment to protect human body against injuries from stabbing. The conventional SRBAs shared low wearing frequency since they are heavy and poor in flexibility. This paper designed a structured stab-resistance plate using the model of crocodile armor and manufactured using 3D printing technology-laser sintering (LS). CF(Carbon fiber) was applied to enhance the stab resistance properties of SRBA. The effects of the material and structure were analysed through the stab resistance property tests based on the national standard GA68-2008. It is found that the stab resistance property of flat plates sintered by PA powder and PA/CF are both weaker than that of the structured plate. The penetrating depth of PA/CF structured plate is significantly 2-mm-less than the pure PA structured plate. The SEM observations confirmed the conclusion that addition of the CF largely improved the plate stab resistance property. Moreover, using PA/CF structured plate to produce the stab resistance body armor would result in a weight reduction by about 30-40% as compared to the existing SRBA that was made up of metal plates, which could largely reduce the wearer physical burden and improve the wearing frequency.

  3. 76 FR 35024 - National Institute of Justice Stab-Resistant Body Armor Standard Workshop

    Science.gov (United States)

    2011-06-15

    ... of Justice Programs National Institute of Justice Stab-Resistant Body Armor Standard Workshop AGENCY... Technology (NIST) are jointly hosting workshop focused on the NIJ Stab-Resistant Body Armor Standard. It is... planning to attend are responsible for their own travel arrangements. Registration information may be found...

  4. Analytical assessment of woven fabrics under vertical stabbing - The role of protective clothing.

    Science.gov (United States)

    Hejazi, Sayyed Mahdi; Kadivar, Nastaran; Sajjadi, Ali

    2016-02-01

    Knives are being used more commonly in street fights and muggings. Therefore, this work presents an analytical model for woven fabrics under vertical stabbing loads. The model is based on energy method and the fabric is assumed to be unidirectional comprised of N layers. Thus, the ultimate stab resistance of fabric was determined based on structural parameters of fabric and geometrical characteristics of blade. Moreover, protective clothing is nowadays considered as a strategic branch in technical textile industry. The main idea of the present work is improving the stab resistance of woven textiles by using metal coating method. In the final, a series of vertical stabbing tests were conducted on cotton, polyester and polyamide fabrics. Consequently, it was found that the model predicts with a good accuracy the ultimate stab resistance of the sample fabrics. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. An autopsy case of suicide by hanging with multiple stab wounds of the neck and chest.

    Science.gov (United States)

    Maeda, H; Imura, M; Higuchi, T; Noguchi, K

    1993-01-01

    We report, from the aspect of 'acting' capability, an autopsy case of suicide by hanging in which multiple deep stab wounds were observed in the neck and chest. A 49-year-old man was found dead in a state typical of hanging. His car was found about 100m away with a blood-stained climber's knife on the seat. Multiple incised and stab wounds were in the neck, with a lesion of the right inner jugular vein. Three penetrating stab wounds of the chest punctured the lungs, with pooling of about 500ml of blood in the left thorax and about 100ml in the right. Two other shallow stab wounds were in the chest. All the above wounds were explainable as self-inflicted. From the autopsy findings and the circumstantial evidence, it was concluded that he walked approximately 100m after stabbing his neck and chest and finally committed suicide by hanging.

  6. 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. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  7. Management of stab wounds to the anterior abdominal wall

    Directory of Open Access Journals (Sweden)

    João Baptista Rezende-Neto

    Full Text Available The meeting of the Publication "Evidence Based Telemedicine - Trauma and Emergency Surgery" (TBE-CiTE, through literature review, selected three recent articles on the treatment of victims stab wounds to the abdominal wall. The first study looked at the role of computed tomography (CT in the treatment of patients with stab wounds to the abdominal wall. The second examined the use of laparoscopy over serial physical examinations to evaluate patients in need of laparotomy. The third did a review of surgical exploration of the abdominal wound, use of diagnostic peritoneal lavage and CT for the early identification of significant lesions and the best time for intervention. There was consensus to laparotomy in the presence of hemodynamic instability or signs of peritonitis, or evisceration. The wound should be explored under local anesthesia and if there is no injury to the aponeurosis the patient can be discharged. In the presence of penetration into the abdominal cavity, serial abdominal examinations are safe without CT. Laparoscopy is well indicated when there is doubt about any intracavitary lesion, in centers experienced in this method.

  8. Novel uses of detonator diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, John R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilde, Zakary Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tasker, Douglas George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Francois, Elizabeth Green [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nakamoto, Teagan Kanakanui Junichi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Dalton Kay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Trujillo, Christopher J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-15

    A novel combination of diagnostics is being used to research the physics of detonator initiation. The explosive PETN (Pentaerythritol tetranitrate) commonly used in detonators, is also a piezo-electric material that, when sufficiently shocked, emits an electromagnetic field in the radio frequency (RF) range, along crystal fracture planes. In an effort to capture this RF signal, a new diagnostic was created. A copper foil, used as an RF antenna, was wrapped around a foam fixture encompassing a PETN pellet. Rogowski coils were used to obtain the change in current with respect to time (di/dt) the detonator circuit, in and polyvinylidene difluoride (PVDF) stress sensors were used to capture shockwave arrival time. The goal of these experiments is to use these diagnostics to study the reaction response of a PETN pellet of known particle size to shock loading with various diagnostics including an antenna to capture RF emissions. Our hypothesis is that RF feedback may signify the rate of deflagration to detonation transition (DDT) or lack thereof. The new diagnostics and methods will be used to determine the timing of start of current, bridge burst, detonator breakout timing and RF generated from detonation. These data will be compared to those of currently used diagnostics in order to validate the accuracy of these new methods. Future experiments will incorporate other methods of validation including dynamic radiography, optical initiation and use of magnetic field sensors.

  9. Light-initiated detonation systems

    Science.gov (United States)

    Cooper, Stafford S.; Malone, Philip G.; Bartholomew, Stephen W.; Necker, William J.

    1986-09-01

    Numerous light sources could be employed in detonation systems, but lasers have the most efficient coupling to optical fibers and can generate energetic light pulses required for detonation. Flash lamp-pumped, solid state lasers are presently the most useful light source for explosive initiation. Laser diodes in current production cannot generate enough energy for practical applications. The most useful optical fiber for blast line application is a step index fiber with a large core-to-cladding ratio. The large core minimizes energy losses due to misalignment core of fibers in connectors. Couplers that involve mechanically crimped connectors and cleaved fibers, rather than the epoxy-cemented connectors with polished fibers, provide superior energy transmission due to the reduced carbonization at the fiber end. Detonators for optical initiation systems are similar in basic construction to those employed in electrical initiation systems. Explosive and pyrotechnic charges can also be similar. Either primary or secondary explosives can be initiated in present laser-based systems. Two laser detonation systems are presently accessible; a multiple-shot laser with a single-shot, single fiber system designed for use with detonators containing primary explosives. Additional research related to development of low-energy, photoreactive detonators, continuity checking techniques and improved connectors and fibers can produce significant improvements in presently fielded systems.

  10. 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....... For the restricted case of a nested family of intervals (either every pair of intervals is disjoint or one contains the other), we present a simpler solution based on dynamic trees...

  11. Holmes Tremor Secondary to a Stabbing Lesion in the Midbrain

    Directory of Open Access Journals (Sweden)

    Rubens Gisbert Cury

    2017-12-01

    Full Text Available Background: The development of Holmes tremor (HT after a direct lesion of the midbrain has rarely been reported in the literature, although several etiologies have been linked with HT, such as stroke, brainstem tumors, multiple sclerosis, head trauma, or infections.Phenomenology Shown: A 31-year-old male, having been stabbed in the right eye, presented with a rest and action tremor in the left upper limb associated with left hemiparesis with corresponding post-contrast volumetric magnetic resonance imaging T1 with sagittal oblique reformation showing the knife trajectory reaching the right midbrain.Educational Value: Despite the rarity of the etiology of HT in the present case, clinicians working with persons with brain injuries should be aware of this type of situation.

  12. The spectrum of injuries in buttock stab wounds.

    Science.gov (United States)

    Campion, T; Cross, S

    2017-07-01

    Buttock stab wounds are a surprisingly common and increasing source of presentations to emergency departments. These injuries can have a significant impact on quality of life, and there are a number of often subtle, but significant, injuries that the radiologist must be alert to when interpreting computed tomography examinations in these patients. In this review, we will examine briefly the sociological reasons for the increase in these injuries, discuss appropriate imaging techniques, and provide imaging examples of the clinically important injuries that may be encountered in this region. These injuries include rectal or colonic perforation; genito-urinary trauma, for example urethral injury; injury to the sciatic nerve; and a spectrum of vascular trauma including transection and pseudoaneurysm or arteriovenous fistula formation. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  13. The persistent diagnostic challenge of thoracoabdominal stab wounds.

    Science.gov (United States)

    Berg, Regan J; Karamanos, Efstathios; Inaba, Kenji; Okoye, Obi; Teixeira, Pedro G; Demetriades, Demetrios

    2014-02-01

    Penetrating thoracoabdominal trauma, with potential injury to two anatomic cavities, significantly challenges surgical management, yet this injury pattern has not been reviewed across a large patient series. The trauma registry of a major level 1 center was queried for all adult patients admitted with thoracoabdominal stab wounds between January 1996 and December 2011. The study identified 617 patients; 11% arrived hypotensive (systolic blood pressure undergoing thoracotomy. Among this group, only 1 (2.4%) of 41 had a major thoracic vessel or aortic injury without cardiac trauma. Diaphragmatic injury (DI) occurred in 224 (38%) of 595, with 72 (32.1%) of these 224 demonstrating no computed tomographic evidence of DI. Either hollow viscus injury or DI occurred in 50%. Only 36.8% of liver, 58% of spleen, and 29.8% of kidney injuries required surgical repair. The need for dual-cavitary intervention was associated with a precipitous increase in patient mortality. Patients with thoracoabdominal stab wounds present considerable clinical challenges due to high surgical need, high occult DI incidence, persistently high rates of negative laparotomy, and significant mortality with dual-cavitary intervention. Many patients with solid-organ injuries do not require intervention. High incidence of hollow viscus injury and DI ultimately limits nonoperative management. Laparoscopy is necessary to exclude occult DI. In unstable patients, determination of which anatomic cavity to explore primarily requires exclusion of cardiac injury. In those with equivocal clinical or ultrasonographic evidence of cardiac trauma, laparotomy, with transdiaphragmatic pericardial window, if a causative abdominal injury is not immediately apparent, seems the most effective strategy. Epidemiologic study, level III.

  14. Theoretical investigation on crystal structure, detonation ...

    Indian Academy of Sciences (India)

    lows: P, detonation pressure (GPa); D, the detona- tion velocity (km/s); ρ, the packed density (g/cm3); , the characteristics value of explosives; N, the mol of gas produced by per gram of explosives; M, an ave- rage molar weight of detonation products; and Q, the estimated heat of detonation (kJ/g). The density of each ...

  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. Numerical Investigation of Detonation Combustion Wave in Pulse Detonation Combustor with Ejector

    OpenAIRE

    P. Debnath; K. M. Pandey

    2017-01-01

    Detonation combustion based engines are more efficient compared to conventional deflagration based engines. Pulse detonation engine is the new concept in propulsion technology for future propulsion system. In this contrast, an ejector was used to modify the detonation wave propagation structure in pulse detonation engine combustor. In this paper k-ε turbulence model was used for detonation wave shock pattern simulation in PDE with ejectors at Ansys 14 Fluent platform. The unsteady Euler equat...

  17. Stab Resistance of Shear Thickening Fluid (STF)-Kevlar Composites for Body Armor Applications

    National Research Council Canada - National Science Library

    Egres Jr., R. G; Decker, M. J; Halbach, C. J; Lee, Y. S; Kirkwood, J. E; Kirwood, K. M; Wagner, N. J; Wetzel, E. D

    2004-01-01

    The stab resistance of shear thickening fluid (STF)-Kevlar and STF-Nylon fabric composites are investigated and found to exhibit significant improvements over neat fabric targets of equivalent areal density...

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

    OpenAIRE

    Raikwar; Odiya; Ashish; Sachin

    2015-01-01

    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 . ...

  19. Perforation of the ileum after a stab wound of the gluteal region: a case report

    OpenAIRE

    van Oldenrijk, Jakob; Ünlü, Çaĝdaş; van Wagensveld, Bart A

    2007-01-01

    We present a case of a patient with a seemingly insignificant single gluteal stab wound which led to a solitary perforation of the ileum and delayed peritonitis. This case report illustrates that, despite the absence of any signs of bowel perforation on presentation, a patient may deteriorate gradually in the subsequent hours. This demonstrates the role of clinical observation in high risk gluteal stab wound patients.

  20. 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.

  1. Candida albicans spondylodiscitis following an abdominal stab wound: forensic considerations.

    Science.gov (United States)

    Savall, Frederic; Dedouit, Fabrice; Telmon, Norbert; Rougé, Daniel

    2014-03-01

    Candida albicans spondylodiscitis is a fungal infection of the spine which is still unusual in spite of the increasing frequency of predisposing factors. A 22-year-old man received an abdominal stab wound during a physical assault. Initial medical care included surgery, prolonged use of indwelling vascular catheters with administration of broad-spectrum antibiotics, and hospitalization in intensive care. Two months after the event, the victim experienced back pain in the right lumbar region and septic spondylodiscitis secondary to C. albicans was diagnosed three weeks later. This case is noteworthy because of its clinical forensic context. In France, the public prosecutor orders a medico-legal assessment after an assault for all living victims in order to establish a causal relationship between the assault and its complications. In our case, the patient presented numerous risk factors for candidemia and the forensic specialist reasonably accepted that the causal relationship was certain but indirect. We have only found one published case of spondylodiscitis after an abdominal penetrating injury and the pathogenic agent was not mentioned. We have found no case reported in a forensic context. This unusual observation shows that it may be genuinely difficult to prove the causal relationship between an abdominal penetrating injury and an unusual infectious complication such as fungal spondylodiscitis. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  2. Numerical modeling of sympathetic detonation

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, A.L.; Kershner, J.D.; Mader, C.L.

    1979-11-01

    The sympathetic detonation of small cubes of solid rocket propellant was modeled numerically, using the Eulerian reactive hydrodynamic code 2DE with Forest Fire burn rates. The model was applied to cubes of 1 to 3 in., with excellent agreement between calculated and experimental results. The model also was applied to several propellants and to different experimental arrangements. The blast-wave pressures in the air gap and the induced shock pressures in the acceptor were obtained from the model. The correlation between these pressures was coupled with a study of the effect of the length-to-diameter ratio of a donor cylinder and the necessary conditions for detonation of the acceptor to provide a semiquantitative predictive capability.

  3. Detonation velocity in poorly mixed gas mixtures

    Science.gov (United States)

    Prokhorov, E. S.

    2017-10-01

    The technique for computation of the average velocity of plane detonation wave front in poorly mixed mixture of gaseous hydrocarbon fuel and oxygen is proposed. Here it is assumed that along the direction of detonation propagation the chemical composition of the mixture has periodic fluctuations caused, for example, by layered stratification of gas charge. The technique is based on the analysis of functional dependence of ideal (Chapman-Jouget) detonation velocity on mole fraction (with respect to molar concentration) of the fuel. It is shown that the average velocity of detonation can be significantly (by more than 10%) less than the velocity of ideal detonation. The dependence that permits to estimate the degree of mixing of gas mixture basing on the measurements of average detonation velocity is established.

  4. 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

  5. A combined experimental and numerical study of stab-penetration forces.

    Science.gov (United States)

    Annaidh, Aisling Ní; Cassidy, Marie; Curtis, Michael; Destrade, Michel; Gilchrist, Michael D

    2013-12-10

    The magnitude of force used in a stabbing incident can be difficult to quantify, although the estimate given by forensic pathologists is often seen as 'critical' evidence in medico-legal situations. The main objective of this study is to develop a quantitative measure of the force associated with a knife stabbing biological tissue, using a combined experimental and numerical technique. A series of stab-penetration tests were performed to quantify the force required for a blade to penetrate skin at various speeds and using different 'sharp' instruments. A computational model of blade penetration was developed using ABAQUS/EXPLICIT, a non-linear finite element analysis (FEA) commercial package. This model, which incorporated element deletion along with a suitable failure criterion, is capable of systematically quantifying the effect of the many variables affecting a stab event. This quantitative data could, in time, lead to the development of a predictive model that could help indicate the level of force used in a particular stabbing incident. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. A summary of hydrogen-air detonation experiments

    International Nuclear Information System (INIS)

    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

  7. A Multidisciplinary Study of Pulse Detonation Engine Propulsion

    National Research Council Canada - National Science Library

    Santoro, Robert

    2003-01-01

    .... The multidisciplinary research effort brought together a team of leading researchers in the areas of the initiation and propagation of detonations, liquid hydrocarbon spray detonation, combustion...

  8. A Dynamic Stabbing-Max Data Structure with Sub-Logarithmic Query Time

    OpenAIRE

    Nekrich, Yakov

    2011-01-01

    In this paper we describe a dynamic data structure that answers one-dimensional stabbing-max queries in optimal $O(\\log n/\\log\\log n)$ time. Our data structure uses linear space and supports insertions and deletions in $O(\\log n)$ and $O(\\log n/\\log \\log n)$ amortized time respectively. We also describe a $O(n(\\log n/\\log\\log n)^{d-1})$ space data structure that answers $d$-dimensional stabbing-max queries in $O((\\log n/\\log\\log n)^{d})$ time. Insertions and deletions are supported in $O((\\lo...

  9. Experimental study of thermal comfort on stab resistant body armor.

    Science.gov (United States)

    Ji, Tingchao; Qian, Xinming; Yuan, Mengqi; Jiang, Jinhui

    2016-01-01

    This research aims to investigate the impacts of exercise intensity and sequence on human physiology parameters and subjective thermal sensation when wearing stab resistant body armor under daily working conditions in China [26 and 31 °C, 45-50 % relative humidity (RH)], and to investigate on the relationship between subjective judgments and objective parameters. Eight male volunteers were recruited to complete 3 terms of exercises with different velocity set on treadmill for 90 min at 26 °C and 31 °C, 45-50 % RH. In Exercise 1 volunteers were seated during the test. In Exercise 2, volunteers walked with the velocity of 3 km/h in the first 45 min and 6 km/h in the left 45 min. In Exercise 3, volunteers walked with the velocity of 6 km/h in the first 45 min and 3 km/h in the left 45 min. The body core temperature, skin temperature and subjective judgments were recorded during the whole process. Analysis of variance was performed among all the tests. Individual discrepancy of Exercise 1 is larger than that of Exercise 2 and 3. On the premise of the same walking distance and environmental conditions, core temperature in Exercise 3 is about 0.2 °C lower than that in Exercise 2 in the end; and with the velocity decrease from 6 km/h to 3 km/h in the end, thermal tolerance of Exercise 3 is about 1 degree lower than that in Exercise 2. Skin temperatures of human trunk were at least 1 °C higher than that of limbs. Activity narrows the individual discrepancy on core temperature. Within experimental conditions, decreasing of intensity at last stage makes the core temperature lower and the whole process much tolerable. The core temperature is more sensitive to the external disturbance on the balance of the whole body, and it can reflect the subjective thermal sensation and physical exertion.

  10. 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 engine...

  11. Detonation properties of the nitromethane/ diethylenetriamine solution

    Science.gov (United States)

    Mochalova, Valentina; Utkin, Alexander; Lapin, Sergey

    2015-06-01

    The results of the experimental determination of detonation parameters for the mixture of nitromethane (NM) with diethylenetriamine (DETA) are presented in this work. By the using of a laser interferometer VISAR the stability of detonation waves, detonation velocity and the reaction time with the change of the DETA concentration from 0 to 60 weight percentages were investigated. It is shown that detonation waves are stable up to 25% DETA, and the character reaction time is reduced from 50 ns up to 30 ns with the addition of a few percentages of the sensitizer and then remains almost the constant. With further increase of the DETA concentration the detonation front becomes unstable, and it results in an arising of pulsations with amplitude of 10 microns. The limit concentration of DETA, above which the detonation of the mixture was impossible, was determined. This concentration was equal to 60%. It is shown that the dependence of the detonation velocity on the DETA concentration is non-monotonic. In particular, the increase of detonation velocity in the vicinity of small concentrations of the sensitizer, about 0.1%, was recorded. The work was supported by Russian Foundation for Basic Research (Project 15-03-07830).

  12. 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.

  13. 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.

  14. Development of a high-density nonwoven structure to improve the stab resistance of protective clothing material.

    Science.gov (United States)

    Bao, Limin; Wang, Yanling; Baba, Takeichiro; Fukuda, Yasuhiro; Wakatsuki, Kaoru; Morikawa, Hideaki

    2017-12-07

    The purpose of this research was to enhance the stab resistance of protective clothing material by developing a new high-density nonwoven structure. Ice picks often injure Japanese police officers due to the strict regulation of swords in the country. Consequently, this study was designed to improve stab resistance against ice picks. Most existing anti-stab protective clothing research has focused on various fabrics impregnated with resin, an approach that brings with it problems of high cost and complicated processing. Seldom has research addressed the potential for improving stab resistance by using nonwoven structures, which exhibit better stab resistance than fabric. In this research, we prepared a series of nonwoven structures with densities ranging from about 0.14 g/cm 3 to 0.46 g/cm 3 by varying the number of stacked layers of Kevlar/polyester nonwoven under a hot press. We then proposed two methods for producing such hot-press nonwovens: the multilayer hot-press method and the monolayer hot-press method. Stab resistance was evaluated according to NIJ Standard-0115.00. We also investigated the relationship among nonwoven density, stab resistance, and flexural rigidity, and here we discuss the respective properties of the two proposed methods. Our results show that stab resistance and flexural rigidity increase with nonwoven density, but flexural rigidity of nonwovens prepared using the monolayer hot-press method only shows a slight change as nonwoven density increases. Though the two methods exhibit little difference in maximum load, the flexural rigidity of nonwovens prepared using the monolayer hot-press method is much lower, which contributes to superior wear comfort. Finally, we investigated the mechanism behind the stabbing process. Stabbing with an ice pick is a complicated process that involves many factors. Our findings indicate that nonwovens stop penetration primarily in two ways: nonwoven deformation and fiber fractures.

  15. Tritium labeling of detonation nanodiamonds.

    Science.gov (United States)

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

    2014-03-18

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

  16. Detonation properties of nitromethane/diethylenetriamine solution

    Science.gov (United States)

    Mochalova, V.; Utkin, A.; Lapin, S.

    2017-01-01

    The results of the experimental determination of the detonation parameters of nitromethane (NM) with diethylenetriamine (DETA) solution are presented in this work. With the using of a laser interferometer VISAR the stability of detonation waves, the detonation velocity and the reaction time at the concentration of DETA from 0 to 60 weight percentage were investigated. It is shown that the stability of detonation waves is retained up to 25% DETA, at that the characteristic reaction time is reduced by about half at the addition of several percentage of the sensitizer to NM and then remains almost constant. The increase of the detonation velocity in the vicinity of the small, about 0.1%, concentrations of sensitizer is recorded.

  17. Molecular dynamics simulations of weak detonations.

    Science.gov (United States)

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

    2011-12-01

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

  18. Clinical patterns of primary stabbing headache: a single clinic-based prospective study.

    Science.gov (United States)

    Kim, Dong Yeop; Lee, Mi Ji; Choi, Hyun Ah; Choi, Hanna; Chung, Chin-Sang

    2017-12-01

    The clinical features and disease courses of primary stabbing headache (PSH) are diverse. We aimed to identify distinct clinical patterns of PSH. We prospectively screened consecutive first-visit patients who presented with stabbing headache at the Samsung Medical Centre Headache Clinic from June 2015 to March 2016. Demographics, headache characteristics, and disease courses were prospectively evaluated. After discerning factors related to the chronicity at the time of presentation, clinical patterns were identified based on the frequency (daily vs. intermittent), clinical course (remitted or not), and total disease duration (3 months). In the 65 patients with PSH included in this study, monophasic (n = 31), intermittent (n = 17), and chronic daily (n = 12) patterns were identified. The median disease durations were 9 days for monophasic PSH, 9 months for chronic daily PSH, and 2 years for intermittent PSH. The features of monophasic PSH were greater severity, single and side-locked locations, more attacks per day, daily occurrence, and good treatment response. Chronic daily PSH was associated with female predominance, longer-lasting stabs, and multiple or migrating locations on bilateral or alternating sides. The characteristics of intermittent PSH included female predominance and sporadic stabs with less intensity. Our study demonstrated distinct clinical patterns of PSH. In addition to help early recognition of disease, our findings suggest different pathophysiologic mechanisms. Future prospective studies are required to reveal the etiologies of these different PSH patterns and their optimal treatment strategies.

  19. 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

  20. 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.

  1. STABILITY OF PLASMIDS IN 5 STRAINS OF SALMONELLA MAINTAINED IN STAB CULTURE AT DIFFERENT TEMPERATURES

    DEFF Research Database (Denmark)

    Olsen, J. E.; Brown, D. J.; Baggesen, Dorte Lau

    1994-01-01

    Four strains of Salmonella berta and one of Salm. enteritidis were stored as stab cultures in sugar-free agar at 5 degrees, 22 degrees and 30 degrees C and in 15% glycerol at -80 degrees C. The stability of the plasmid profiles in each of the strains was monitored over a period of 2.5 years. Plas...

  2. 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.

  3. Impact of body mass index on injury in abdominal stab wounds: implications for management.

    Science.gov (United States)

    Bloom, Matthew B; Ley, Eric J; Liou, Douglas Z; Tran, Tri; Chung, Rex; Melo, Nicolas; Margulies, Daniel R

    2015-07-01

    Although it is assumed that obese patients are naturally protected against anterior abdominal stab wounds, the relationship has never been formally studied. We sought to examine the impact of body mass index (BMI) on severity of sustained injury, need for operation, and patient outcomes. We conducted a review of all patients presenting with abdominal stab wounds at an urban level I trauma center from January 2000-December 2012. Patients were divided into groups based on their BMI (35). Data abstracted included baseline demographics, physiologic data, and characterization of whether the stab wound had violated the peritoneum, caused intra-abdominal injury, or required an operation that was therapeutic. The one-sided Cochran-Armitage trend test was used for significance testing of the protective effect. Of 281 patients with abdominal stab wounds, 249 had complete data for evaluation. Chest and abdomen abbreviated injury scale trends decreased with increasing BMI, as did overall injury severity score, the percent of patients severely injured (injury severity score ≥ 25), and length of intensive care unit stay. Rates of peritoneal violation (100%, 84%, 77%, and 74%; P = 0.077), visceral injury (83%, 56%, 50%, and 30%; P = 0.022), and injury requiring a therapeutic operation (67%, 45%, 40%, and 20%; P = 0.034) all decreased with increasing BMI. Patients in the thinnest group required an operation three times more often than those in the most obese. Increased BMI protects patients with abdominal stab wounds and is associated with lower incidence of severe injury and need for operation. Heavier patients may be more suitable to observation and serial examinations, whereas very thin patients are more likely to require an operation and be critically injured. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Reinforced concrete wall under hydrogen detonation

    International Nuclear Information System (INIS)

    Saarenheimo, A.

    2000-11-01

    The structural integrity of a reinforced concrete wall in the BWR reactor building under hydrogen detonation conditions has been analysed. Of particular interest is whether the containment integrity can be jeopardised by an external hydrogen detonation. The load carrying capacity of a reinforced concrete wall was studied. The detonation pressure loads were estimated with computerised hand calculations assuming a direct initiation of detonation and applying the strong explosion theory. The results can be considered as rough and conservative estimates for the first shock pressure impact induced by a reflecting detonation wave. Structural integrity may be endangered due to slow pressurisation or dynamic impulse loads associated with local detonations. The static pressure following the passage of a shock front may be relatively high, thus this static or slowly decreasing pressure after a detonation may damage the structure severely. The mitigating effects of the opening of a door on pressure history and structural response were also studied. The non-linear behaviour of the wall was studied under detonations corresponding a detonable hydrogen mass of 0.5 kg and 1.428 kg. Non-linear finite element analyses of the reinforced concrete structure were carried out by the ABAQUS/Explicit program. The reinforcement and its non-linear material behaviour and the tensile cracking of concrete were modelled. Reinforcement was defined as layers of uniformly spaced reinforcing bars in shell elements. In these studies the surrounding structures of the non-linearly modelled reinforced concrete wall were modelled using idealised boundary conditions. Especially concrete cracking and yielding of the reinforcement was monitored during the numerical simulation. (au)

  5. Assessing the Effect of the Role of Detonation Wave Curvature on the Firing Times of High Voltage Detonators

    Science.gov (United States)

    Drake, Rod; Explosive Materials; Initiation Science Group Team

    2017-06-01

    In detonators the lost time is the difference between the measured and calculated time for the reactive wave to transit the explosive charge. The calculated time is derived from the charge thickness and the steady state detonation velocity. For both EBW and EFI detonators the lost time is significant and, for detonators of comparable dimensions, greater in EBW detonators. Typically, the lost time is attributed to a finite growth to detonation time. The bridgewires and foil flyers of EBW and EFI detonators respectively establish reaction fronts over very small areas in the explosive. Even with a significant run to detonation distance, the detonation front may be expected to be highly curved and, thus, have a detonation velocity below the steady state velocity. Consequently, the time and distance required for a steady state detonation velocity to be established may also contribute to the lost time in EBW and EFI detonators. To assess the relevance of wave curvature on lost time a simple analytical model has been developed which takes into account growth to detonation and detonation wave curvature effects. The model showed that detonation wave curvature could be responsible for at least some of the lost time of EBW detonators. British Crown Owned Copyright 2017/AWE.

  6. Qualitative and quantitative analysis of detonation products

    International Nuclear Information System (INIS)

    Xie Yun

    2005-01-01

    Different sampling and different injection method were used during analyzing unknown detonation products in a obturator. The sample analyzed by gas chromatography and gas chromatography/mass spectrum. Qualitative analysis was used with CO, NO, C 2 H 2 , C 6 H 6 and so on, qualitative analysis was used with C 3 H 5 N, C 10 H 10 , C 8 H 8 N 2 and so on. The method used in the article is feasible. The results show that the component of detonation in the study is negative oxygen balance, there were many pollutants in the detonation products. (authors)

  7. Exergetic efficiency analysis of hydrogen–air detonation in pulse detonation combustor using computational fluid dynamics

    OpenAIRE

    Pinku Debnath; KM Pandey

    2017-01-01

    Exergy losses during the combustion process, heat transfer, and fuel utilization play a vital role in the analysis of the exergetic efficiency of combustion process. Detonation is thermodynamically more efficient than deflagration mode of combustion. Detonation combustion technology inside the pulse detonation engine using hydrogen as a fuel is energetic propulsion system for next generation. In this study, the main objective of this work is to quantify the exergetic efficiency of hydrogen–ai...

  8. Study on Performance of Detonation-Driven Shock Tube(Compressible Flow and Detonation)

    OpenAIRE

    YAMANAKA, Akio; ARIGA, Yosuke; 小原, 哲郎; CAI, Pin; 大八木, 重治

    2002-01-01

    A detonation-driven shock tube firstly designed by H.R. Yu is considered to be a useful apparatus for producing high-enthalpy flow. In this apparatus, a strong shock wave is generated by detonating an oxygen-hydrogen mixture (oxy-hydrogen) and the driver gas temperature and pressure are extremely high compared with those of a conventional shock tube. However, the structure of the detonation wave is not uniform, e.g., the detonation wave has three-dimensional cellular structures and multiple t...

  9. 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. ...

  10. Aerospike Nozzle for Rotating Detonation Engine Application

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents a graduate MS research thesis on improving the efficiency of rotating detonation engines by using aerospike nozzle technologies. A rotating...

  11. Underwater sympathetic detonation of pellet explosive

    Science.gov (United States)

    Kubota, Shiro; Saburi, Tei; Nagayama, Kunihito

    2017-06-01

    The underwater sympathetic detonation of pellet explosives was taken by high-speed photography. The diameter and the thickness of the pellet were 20 and 10 mm, respectively. The experimental system consists of the precise electric detonator, two grams of composition C4 booster and three pellets, and these were set in water tank. High-speed video camera, HPV-X made by Shimadzu was used with 10 Mfs. The underwater explosions of the precise electric detonator, the C4 booster and a pellet were also taken by high-speed photography to estimate the propagation processes of the underwater shock waves. Numerical simulation of the underwater sympathetic detonation of the pellet explosives was also carried out and compared with experiment.

  12. Confined detonations with cylindrical and spherical symmetry

    International Nuclear Information System (INIS)

    Linan, A.; Lecuona, A.

    1979-01-01

    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/pγ-K for the detonated and compressed inert media are used. For liquid or solid reflectors a more appropriate equation is used. (Author) 8 refs

  13. Benign Liver Tumors

    Science.gov (United States)

    ... Legacy Society Make Gifts of Stock Donate Your Car Personal Fundraising Partnership & Support Share Your Story Spread the Word Give While You Shop Contact Us Donate Now Benign Liver Tumors Back ...

  14. Chirped fiber Bragg grating detonation velocity sensing.

    Science.gov (United States)

    Rodriguez, G; Sandberg, R L; McCulloch, Q; Jackson, S I; Vincent, S W; Udd, E

    2013-01-01

    An all optical-fiber-based approach to measuring high explosive detonation front position and velocity is described. By measuring total light return using an incoherent light source reflected from a linearly chirped fiber Bragg grating sensor in contact with the explosive, dynamic mapping of the detonation front position and velocity versus time is obtained. We demonstrate two calibration procedures and provide several examples of detonation front measurements: PBX 9502 cylindrical rate stick, radial detonation front in PBX 9501, and PBX 9501 detonation along curved meridian line. In the cylindrical rate stick measurement, excellent agreement with complementary diagnostics (electrical pins and streak camera imaging) is achieved, demonstrating accuracy in the detonation front velocity to below the 0.3% level when compared to the results from the pin data. Finally, an estimate on the linear spatial and temporal resolution of the system shows that sub-mm and sub-μs levels are attainable with proper consideration of the recording speed, detection sensitivity, spectrum, and chirp properties of the grating.

  15. Ignition of detonation in accreted helium envelopes

    Science.gov (United States)

    Ami Glasner, S.; Livne, E.; Steinberg, E.; Yalinewich, A.; Truran, James W.

    2018-02-01

    Sub Chandrasekhar CO white dwarfs accreting helium have been considered as candidates for SNIa progenitors since the early 1980's (helium shell mass >0.1M⊙). These models, once detonated did not fit the observed spectra and light curve of typical SNIa observations. New theoretical work examined detonations on much less massive (<0.05M⊙) envelopes. They find stable detonations that lead to light curves, spectra and abundances that compare relatively well with the observational data. The exact mechanism leading to the ignition of helium detonation is a key issue, since it is a mandatory first step for the whole scenario. As the flow of the accreted envelope is unstable to convection long before any hydrodynamic phenomena develops, a multidimensional approach is needed in order to study the ignition process. The complex convective reactive flow is challenging to any hydrodynamical solver. According to our best knowledge all previous 2D studies ignited the detonation artificially. We present here, for the first time, fully consistent results from two hydrodynamical 2D solvers that adopt two independent accurate schemes. For both solvers an effort was made to overcome the problematics raised by the finite resolution and numerical diffusion by the advective terms. Our best models lead to the ignition of a detonation in a convective cell. Our results are robust and the agreement between the two different numerical approaches is very good.

  16. 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.

  17. 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.

  18. Complex Suicide by Self-stabbing and Drowning: A Case Report and a Review of Literature.

    Science.gov (United States)

    Peyron, Pierre-Antoine; Casper, Thierry; Mathieu, Olivier; Musizzano, Yuri; Baccino, Eric

    2018-03-01

    Sharp force injuries and drowning are methods exceptionally combined in complex suicides. We report a challenging case of complex suicide by self-stabbing and drowning that illustrates the difficulty in discriminating between homicide and suicide in such circumstances of death. The corpse of a young man was found submerged in a river, stabbed nine times with two wounds that had penetrated the thorax and had caused lung injuries and a hemopneumothorax. The postmortem and histological examinations were consistent with a death caused by drowning, but the manner of death still remained undetermined. Police investigation finally concluded to a suicide, although no suicide note had been left and the victim had no underlying diagnosed mental disorder. The parameters that may help distinguish suicide from homicide at the autopsy should be interpreted in light of a thorough forensic investigation to determine the exact manner of death in such a case. © 2017 American Academy of Forensic Sciences.

  19. 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.

  20. Serial knife stabbings with HIV exposure--implications for post-exposure prophylaxis.

    Science.gov (United States)

    Jorgensen, Pernille; Marcus, Ulrich; Albrecht, Helmut; Suttorp, Norbert; Schürmann, Dirk

    2010-01-01

    Thirty-three persons became victims of a serial knife stabbing incident. One of the first victims one day later disclosed that he was HIV-infected. Thereafter thirty-one victims initiated HIV post-exposure prophylaxis (PEP), one exposed patient declined. None of the victims evaluated had seroconverted six months later. In most such incidents HIV exposure will be difficult to rule out as reliable information on the HIV serostatus of all serial victims will be lacking. It appears prudent, however, to inform serial stab victims about the potential risk of HIV transmission and to at least consider PEP in such scenarios. 2009 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

  1. Detonability of H2-air-diluent mixtures

    International Nuclear Information System (INIS)

    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 2 -air mixtures, undiluted and diluted with CO 2 and H 2 O for a range of H 2 concentration, initial temperature and pressure. The results show that the addition of either CO 2 or H 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

  2. Astrocyte morphology after cortical stab wound revealed by single-cell confocal 3D morphometry

    Czech Academy of Sciences Publication Activity Database

    Chvátal, Alexandr; Anděrová, Miroslava; Petřík, David; Syková, Eva

    č. 2 (2003), s. 63 ISSN 0894-1491. [European Meeting on Glial Cell Function in Health and Disease /6./. Berlín, 03.09.2003-06.09.2003] R&D Projects: GA ČR GA305/02/1528; GA MŠk LN00A065 Institutional research plan: CEZ:AV0Z5039906; CEZ:MSM 111300004 Keywords : cortical stab wound * morphometry Subject RIV: FH - Neurology Impact factor: 4.677, year: 2003

  3. IP-telefon säästab oluliselt sidekulusid / Kristjan Otsmann

    Index Scriptorium Estoniae

    Otsmann, Kristjan, 1971-

    2005-01-01

    Telekomifirma Norby Telecomi poolt pakutavast IP-telefonist ehk helistamisest läbi Interneti, millega saab vähendada sidekulusid mitmeid kordi. Erinevatest internetipõhise kõnesidelahenduse lisateenustest. Vt. samas: Saaremaa Spa Hotellid säästab tuhandeid kroone kuus [intervjuu Saaremaa Spa Hotellide IT-juhiga Andri Võrguga]; Kuus olulist tööd enne IP-lahenduse tellimist

  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. Prognostic parameters in benign astrocytomas

    DEFF Research Database (Denmark)

    Westergaard, L; Gjerris, F; Klinken, L

    1993-01-01

    To elucidate the prognosis of different types of benign astrocytomas and to ascertain whether patients with partially resected benign astrocytomas, or any subtype of these, would benefit from postoperative radiotherapy, we studied retrospectively material comprising 300 patients with benign astro...... time of patients with non-pilocytic supratentorial benign astrocytomas. The study emphasizes the necessity of a prospective combined multicenter analysis of the effect of radiation on benign astrocytomas....

  6. Prognostic parameters in benign astrocytomas

    DEFF Research Database (Denmark)

    Westergaard, L; Gjerris, F; Klinken, L

    1993-01-01

    To elucidate the prognosis of different types of benign astrocytomas and to ascertain whether patients with partially resected benign astrocytomas, or any subtype of these, would benefit from postoperative radiotherapy, we studied retrospectively material comprising 300 patients with benign...... time of patients with non-pilocytic supratentorial benign astrocytomas. The study emphasizes the necessity of a prospective combined multicenter analysis of the effect of radiation on benign astrocytomas....

  7. Reignition of detonations by reflected shocks

    Science.gov (United States)

    Jones, D. A.; Sichel, M.; Oran, E. S.

    1995-06-01

    Numerical simulations are used to study the diffraction, decay, and reignition that occurs when a detonation propagates past an increase in cross-sectional area in a rectangular tube. The computations solve the time-dependent two-dimensional equations describing a reactive flow in an argon-diluted stoichiometric hydrogen-oxygen mixture at atmospheric pressure. Previous studies have shown that soon after transmission to a larger area, the reaction front decouples from the leading shock and forms a decaying blast wave (“bubble”) in the larger tube. Then, depending on the initial conditions, the detonation either continues to decay or is reignited as the bubble reflects off confining surfaces. For a strongly overdriven initiating detonation, reignition occurs through an interaction between the bubble and the original contact surface. For a more weakly driven system, reignition can occur in two ways: either in the slip line and Mach stem of the Mach reflection formed when the bubble reflects off the bottom surface of the tube, or by multiple shock interactions that occur when the reflected bubble overtakes the initial detonation front. The computations show the evolution and development of the cellular structure of the steady detonation front.

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

    International Nuclear Information System (INIS)

    Dolmatov, Valerii Yu

    2007-01-01

    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.

  9. [Benign chronic pain].

    Science.gov (United States)

    Serrie, A; Thurel, C

    1994-09-15

    Recent data indicate that 25 to 30% of the population in industrialized countries suffers from benign chronic pain. Among these patients, 50 to 75% are professionally incapable for varied lengths of time, from a few days to some weeks or months, or even definitively. The aetiology and clinical presentation of chronic benign pain are enormously varied because this definition includes such different pathologies as headache, pain of rheumatologic, postsurgical, organic, and post-zoster origin, lombalgia, radiculalgia, post-amputation pain, neuropathologic pain, causalgia, algoneurodystrophic pain, psychosomatic and idiopathic pain. Since these syndromes and causes of pain could not be discussed individually, they have been grouped according to their neurophysiology and pathophysiology.

  10. Benign Jaw Lesions.

    Science.gov (United States)

    Gohel, Anita; Villa, Alessandro; Sakai, Osamu

    2016-01-01

    There are both odontogenic and nonodontogenic benign lesions in the maxilla and mandible. These lesions may have similar imaging features, and the key radiographic features are presented to help the clinician narrow the differential diagnosis and plan patient treatment. Both intraoral and panoramic radiographs and advanced imaging features are useful in assessing the benign lesions of the jaws. The location, margins, internal contents, and effects of the lesions on adjacent structures are important features in diagnosing the lesions. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Development of new model for high explosives detonation parameters calculation

    Directory of Open Access Journals (Sweden)

    Jeremić Radun

    2012-01-01

    Full Text Available The simple semi-empirical model for calculation of detonation pressure and velocity for CHNO explosives has been developed, which is based on experimental values of detonation parameters. Model uses Avakyan’s method for determination of detonation products' chemical composition, and is applicable in wide range of densities. Compared with the well-known Kamlet's method and numerical model of detonation based on BKW EOS, the calculated values from proposed model have significantly better accuracy.

  12. Pseudoideal detonation of mechanoactivated mixtures of ammonium perchlorate with nanoaluminum

    Science.gov (United States)

    Shevchenko, A. A.; Dolgoborodov, A. Yu; Brazhnikov, M. A.; Kirilenko, V. G.

    2018-01-01

    Detonation properties of mechanochemical activated ammonium perchlorate with aluminum (AP–Al) mixtures with increased detonation velocity was studied. For compositions with nanoscale aluminum was obtained nonmonotonic dependence of the detonation velocity vs reciprocal diameter. The results generally showed that the combined usage of mechanical activation and nanoscale components of explosive mixtures can significantly increase the detonation ability and reduce the critical diameter to d cr = 7 mm.

  13. Multistage reaction pathways in detonating high explosives

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  14. 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.

  15. Unsteady detonations driven by first-order phase transformations

    Energy Technology Data Exchange (ETDEWEB)

    Rabie, R.L.; Fickett, W.

    1978-01-01

    Reactive waves supported by the energy released during a phase transformation are examined as elementary detonations. It is found that a class of eigenvalue detonations exist containing the well known Chapman-Jouguet solution as a particular case. In general the set of eigenvalue detonations are unsteady in any single inertial reference frame.

  16. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

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

  17. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Science.gov (United States)

    2010-07-01

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

  18. 30 CFR 57.6400 - Compatibility of electric detonators.

    Science.gov (United States)

    2010-07-01

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

  19. 30 CFR 56.6400 - Compatibility of electric detonators.

    Science.gov (United States)

    2010-07-01

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

  20. Benign bone tumors

    International Nuclear Information System (INIS)

    Gilday, D.L.; Ash, J.M.

    1976-01-01

    There is little information in the literature concerning the role of bone scanning in benign bone neoplasms except for sporadic reports. Since the advent of /sup 99m/Tc-polyphosphate, bone imaging has proven feasible and useful in locating the cause of bone pain, such as in osteoid osteomas, which are not always radiologically apparent, and in evaluating whether or not a radiologic lesion is indeed benign and solitary. Blood-pool images are particularly important in neoplastic disease, since the absence of hyperemia in the immediate postinjection period favors the diagnosis of a benign neoplasm, as does low-grade uptake on the delayed study. The scan, including pinhole magnification images, is especially valuable in diagnosing lesions in the spine and pelvis, which are poorly seen radiologically. We have studied various types of benign bone tumors, including simple and aneurysmal bone cysts, fibrous cortical defects, and nonossifying fibromas, all of which had minimal or no increased uptake of the radiopharmaceutical, unless traumatized. Although osteochondromas and enchondromas showed varied accumulation of activity, the scan was useful in differentiating these from sarcomatous lesions. All osteoid osteomas demonstrated marked activity, and could be accurately located preoperatively, as could the extent of fibrous dysplasia. The bone scan in the reticuloses also showed abnormal accumulation of activity, and aided in arriving at the prognosis and treatment of histiocytic bone lesions

  1. Uraemia from Benign Hypertension

    African Journals Online (AJOL)

    tance,' and the criteria for the recognition of malignant hypertension have become so well established that there is no dispute about the diagnosis when this condition ends in uraemia. By contrast, benign hypertension mani- fests itself mainly as cardiac or cerebrovascular disease,"" and although the occurrence of renal ...

  2. Investigation of hydrogen-deflagration/-detonation

    International Nuclear Information System (INIS)

    Breitung, W.; Redlinger, R.; Werle, H.; Moeschke, M.

    1992-01-01

    The static and dynamic loads of a PWR-containment from hydrogen combustion are investigated theoretically and experimentally. The primary goal is the determination of realistic, not too conservative, upper bounds. The load data are needed to define design requirements for a core-melt resistant containment structure. The following work was performed in 1991: balloon tests; design of a medium scale detonation tube; development of a 1D detonation code; analytical study with SNL/Albuquerque, USA and documentation and presentation of results. (orig./DG)

  3. Benign gastric filling defect

    Energy Technology Data Exchange (ETDEWEB)

    Oh, K. K.; Lee, Y. H.; Cho, O. K.; Park, C. Y. [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  4. Benign gastric filling defect

    International Nuclear Information System (INIS)

    Oh, K. K.; Lee, Y. H.; Cho, O. K.; Park, C. Y.

    1979-01-01

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  5. Importance of diagnostic laparoscopy in the assessment of the diaphragm after left thoracoabdominal stab wound: A prospective cohort study.

    Science.gov (United States)

    Yücel, Metin; Özpek, Adnan; Tolan, Hüseyin Kerem; Başak, Fatih; Baş, Gürhan; Ünal, Ethem; Alimoğlu, Orhan

    2017-03-01

    Stab wounds in the left thoracoabdominal region may cause diaphragmatic injury. The aim of the present study was to determine incidence of diaphragmatic injury and role of diagnostic laparoscopy in detection of injury in patients with left thoracoabdominal stab wound. Total of 81 patients (75 male, 6 female; mean age 27.5±9.8 years; range 14 to 60 years) who presented with left thoracoabdominal stab wound between April 2009 and September 2014 were evaluated. Laparotomy was performed on patients who had hemodynamic instability, signs of peritonitis, or organ evisceration. Remaining patients were followed conservatively. After 48 hours, diagnostic laparoscopy was performed on patients without laparotomy indication to examine the left diaphragm for injury. Follow-up and treatment findings were prospectively evaluated. Thirteen patients underwent laparotomy while diagnostic laparoscopy was performed on remaining 68 patients. Left diaphragmatic injury was observed in 19 patients (23.5%) in the study group. Four injuries were diagnosed by laparotomy and 15 were diagnosed by laparoscopy. Presence of hemopneumothorax did not yield difference in incidence of diaphragmatic injury (p=0.131). No significant difference was detected in terms of diaphragmatic injury with respect to entry site of stab wound in the thoracoabdominal region (p=0.929). It is important to evaluate the diaphragm in left thoracoabdominal stab injuries, and diagnostic laparoscopy is still the safest and most feasible method.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-01-01

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

  7. Exergetic efficiency analysis of hydrogen–air detonation in pulse detonation combustor using computational fluid dynamics

    Directory of Open Access Journals (Sweden)

    Pinku Debnath

    2017-03-01

    Full Text Available Exergy losses during the combustion process, heat transfer, and fuel utilization play a vital role in the analysis of the exergetic efficiency of combustion process. Detonation is thermodynamically more efficient than deflagration mode of combustion. Detonation combustion technology inside the pulse detonation engine using hydrogen as a fuel is energetic propulsion system for next generation. In this study, the main objective of this work is to quantify the exergetic efficiency of hydrogen–air combustion for deflagration and detonation combustion process. Further detonation parameters are calculated using 0.25, 0.35, and 0.55 of H2 mass concentrations in the combustion process. The simulations have been performed for converging the solution using commercial computational fluid dynamics package Ansys Fluent solver. The details of combustion physics in chemical reacting flows of hydrogen–air mixture in two control volumes were simulated using species transport model with eddy dissipation turbulence chemistry interaction. From these simulations it was observed that exergy loss in the deflagration combustion process is higher in comparison to the detonation combustion process. The major observation was that pilot fuel economy for the two combustion processes and augmentation of exergetic efficiencies are better in the detonation combustion process. The maximum exergetic efficiency of 55.12%, 53.19%, and 23.43% from deflagration combustion process and from detonation combustion process, 67.55%, 57.49%, and 24.89%, are obtained from aforesaid H2 mass fraction. It was also found that for lesser fuel mass fraction higher exergetic efficiency was observed.

  8. Cervical spondylodiscitis with epidural abscess after knife stab wounds to the neck: A case report.

    Science.gov (United States)

    Voelker, Anna; von der Hoeh, Nicolas H; Gulow, Jens; Heyde, Christoph-Eckhard

    2015-08-01

    Cervical spondylodiscitis is usually caused by pyogenic infections, associated with retropharyngeal abscesses, or due to the swallowing of foreign bodies. No cases of cervical spondylodiscitis caused by a penetrating neck injury have been published in the literature. We describe a case of cervical spondylodiscitis after multiple knife stab wounds to the lateral soft tissue of the neck. Case report and review of the literature. A 54-year-old patient was brought to our clinic with destructive spondylodiscitis C3/4 with paravertebral and epidural abscesses. He had been involved in a fight and had suffered multiple stab wounds to his neck with a knife 1 month prior. The initial CT scan had revealed one deeper wound canal behind the sternocleidomastoid muscle on the left side without any injury to the vessels. The wound was cleaned and an antibiotic therapy with cefuroxime was given for 1 week. After an uneventful and complete healing of the wound the patient developed severe neck pain. Inflammatory laboratory parameters were elevated, and a MRI of the neck revealed a distinct spondylodiscitis C3/4 with paravertebral and epidural abscess formations. Surgery was performed and included debridement, abscess drainage, decompression of the spinal canal, fusion of the C3/4 segment using an autologous iliac crest bone graft and a plate osteosynthesis. A course of calculated antibiotic therapy was administered for 8 weeks. Normal laboratory parameters and no radiological signs of an ongoing inflammatory process were observed during follow-up examinations. The C3/4 segment was consolidated. Stab wound injuries to the neck not only bear the risk of injuries to the nerves, vessels and organs of the neck but also increase the risk of developing secondary spondylodiscitis. Specifically, cervical spondylodiscitis can result in distinct neurological symptoms, and surgical intervention should be performed in a timely manner. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Spinal stab injury with retained knife blades: 51 Consecutive patients managed at a regional referral unit.

    Science.gov (United States)

    Enicker, Basil; Gonya, Sonwabile; Hardcastle, Timothy C

    2015-09-01

    Spinal stab wounds presenting with retained knife blades (RKB) are uncommon, often resulting in spinal cord injury (SCI) with catastrophic neurological consequences. The purpose of this study is to report a single unit's experience in management of this pattern of injury at this regional referral centre. Retrospective review of medical records identified 51 consecutive patients with spinal stabs presenting with a RKB at the Neurosurgery Department at Inkosi Albert Luthuli Central Hospital between January 2003 and February 2015. The data was analyzed for patient characteristics, level of the RKB, neurological status using the ASIA impairment scale, associated injuries, radiological investigations, management, hospital length of stay, complications and mortality. The mean age was 28±10.9 years (range 14-69), with 45 (88%) males (M: F=7.5:1). The median Injury Severity Score was 16 (range 4-26). RKB were located in the cervical [9,18%], thoracic [38,74%], lumbar [2,4%] and sacral [2,4%] spine. Twelve patients (24%) sustained complete SCI (ASIA A), while 21 (41%) had incomplete (ASIA B, C, D), of which 17 had features of Brown-Sequard syndrome. Eighteen (35%) patients were neurologically intact (ASIA E). There were 8 (16%) associated pneumothoraces and one vertebral artery injury. Length of hospital stay was 10±7.1 days (range 1-27). One patient (2%) died during this period. Stab injuries to the spine presenting with RKB are still prevalent in South Africa. Resources should be allocated to prevention strategies that decrease the incidence of inter-personal violence. All RKBs should be removed in the operating theatre by experienced surgeons to minimise complications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Laparoscopic diagnostic peritoneal lavage (L-DPL): A method for evaluation of penetrating abdominal stab wounds.

    Science.gov (United States)

    Krausz, Michael M; Abbou, Benyamine; Hershko, Dan D; Mahajna, Ahmad; Duek, Daniel S; Bishara, Bishara; Israelit, Shlomo H

    2006-03-24

    The management of penetrating abdominal stab wounds has been the subject of continued reappraisal and controversy. In the present study a novel method which combines the use of diagnostic laparoscopy and DPL, termed laparoscopic diagnostic peritoneal lavage (L-DPL) is described Five trauma patients with penetrating injuries to the lower chest or abdomen were included. Standard videoscopic equipment is utilized for the laparoscopic trauma evaluation of the injured patient. When no significant injury is detected, the videoscope is withdrawn and 1000 mL of normal saline is infused through the abdominal trochar into the peritoneal cavity, and the effluent fluid studied for RBCs, WBC, amylase debry, bile as it is uced in regular diagnostic peritoneal lavage Laparoscopic peritoneal lavage (L-DPL) was then performed and proved to be negative in all 5 patients. RBC lavage counts above 100,000/mcrl were not considered as a positive lavage result, because the bleeding source was directly observed and controlled laparoscopically. All patients recovered uneventfully and were released within 3 days. This procedure combines the visual advantages of laparoscopy together with the sensitivity and specificty of DPL for the diagnosis of significant penetrating intra-abdominal injury, when the diagnostic strategy of selective consevatism for abdominal stab wounds is adopted. A method of laparoscopic diagnostic peritoneal lavage (L-DPL) in hemodynamically stable patients with penetrating lower thoracic or abdominal stab wounds is described. The method is especially applicable for trauma surgeons with only basic experience in laparoscopic technique. This procedure is used to obtain conclusive evidence of significant intra-abdominal injury, confirm peritoneal penetration, control intra-abdominal bleeding, and repair lacerations to the diaphragm and abdominal wall. The combination of laparoscopy and DPL afforded by the L-DPL method adds to the sensitivity and specificity of DPL, and

  11. Rogowski coils for studies of detonator initiation

    Science.gov (United States)

    Tasker, Douglas

    2017-06-01

    The Rogowski coil dates back to 1887 and it has commonly been employed to measure rapid changes of electrical currents without direct contact with the circuits, especially in high energy density applications. Recently, it has been used to measure currents in relatively low energy devices such as semiconductor circuits; here we report its utility in the analysis of detonator initiation. From an electrical perspective, the coil is essentially an air-cored transformer and measures the temporal rate of change of current dI/dt. Following a careful characterization of the circuit, an accurate measurement of this derivative is shown to provide a complete solution of the detonator circuit, including current, voltage, power and energy delivered to the detonator. The dependence of the electrical sensitivity, accuracy and bandwidth on coil design will be discussed and a new printed circuit design will be presented. Interesting features in the initiation of exploding bridgewire detonators have been observed with this coil and the results of various experiments will be discussed.

  12. Mach reflection of a ZND detonation wave

    Science.gov (United States)

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

    2015-05-01

    The Mach reflection of a ZND detonation wave on a wedge is investigated numerically. A two-step chain-branching reaction model is used giving a thermally neutral induction zone followed by a chemical reaction zone for the detonation wave. The presence of a finite reaction zone thickness renders the Mach reflection process non-self-similar. The variation of the height of the Mach stem with distance of propagation does not correspond to a straight curve from the wedge apex as governed by self-similar three-shock theory. However, the present results indicate that in the near field around the wedge apex, and in the far field where the reaction zone thickness is small compared to the distance of travel of the Mach stem, the behavior appears to be self-similar. This corresponds to the so-called frozen and equilibrium limit pointed out by Hornung and Sanderman for strong discontinuity shock waves and by Shepherd et al. for cellular detonations. The critical wedge angle for the transition from regular to Mach reflection is found to correspond to the value determined by self-similar three-shock theory, but not by reactive three-shock theory for a discontinuous detonation front.

  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

  14. 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.

  15. 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.; Gerlach, L. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology; Tagawa, H. [Nuclear Power Engineering Corp., Tokyo (Japan); Malliakos, A. [Nuclear Regulatory Commission, Washington, DC (United States)

    1995-12-31

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

  16. 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.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

    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

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

    International Nuclear Information System (INIS)

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

    1995-01-01

    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 product,s and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below

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

    Science.gov (United States)

    Ho, Ivan

    2009-11-01

    Pulse Detonation Engines (PDE) is seen to be the next generation propulsion systems due to enhanced thermodynamic efficiencies. One of the limitations in fielding practical designs has been attributed to tube diameters not exceeding 5 inches, thus affecting specific thrust. Novel methods via imploding detonations were investigated to remove such limitations. During the study, a practical computational cell size was first determined so as to capture the required physics for detonation wave propagation using a Hydrogen-Air test case. Through a grid sensitivity analysis, one-quarter of the induction length was found sufficient to capture the experimentally observed detonation wave structure. Test case models utilizing axi-symmetric head-on implosions were studied in order to understand how the implosion process reinforces a detonation wave as it expands. This in effect creates localized overdriven regions, which maintains the transition process to full detonation. A parametric study was also performed to determine the extent of diameter increase for such that practical designs could be fielded. It was found in the study that diameters of up to 12 inches could be achieved with reasonable run length distances.

  20. 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.)

  1. Benign notochordal cell tumors.

    Science.gov (United States)

    Martínez Gamarra, C; Bernabéu Taboada, D; Pozo Kreilinger, J J; Tapia Viñé, M

    Benign notochordal cell tumors (TBCN) are lesions with notochordal differentiation which affect the axial skeleton. They are characterized by asymptomatic or non-specific symptomatology and are radiologically unnoticed because of their small size, or because they are mistaken with other benign bone lesions, such as vertebral hemangiomas. When they are large, or symptomatic, can be differential diagnosis with metastases, primary bone tumors and chordomas. We present a case of a TBCN in a 50-year-old woman, with a sacral lesion seen in MRI. A CT-guided biopsy was scheduled to analyze the lesion, finding that the tumor was not clearly recognizable on CT, so the anatomical references of MRI were used to select the appropriate plane. The planning of the approach and the radio-pathological correlation were determinant to reach the definitive diagnosis. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Synchro-ballistic recording of detonation phenomena

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

  3. Benign acute childhood myositis.

    Science.gov (United States)

    Rajajee, Sarala; Ezhilarasi, S; Rajarajan, K

    2005-05-01

    To describe the clinical and laboratory features of benign acute childhood myositis. 40 children of BACM were seen during October 2001 to February 2002, 22 (52%) were male with mean age of 5.3 years. Duration of illness was 3.97 days. Preceding symptoms included fever, leg pain, vomiting and inability to walk. A provisional diagnosis of viral myositis was made in 26 (66%). Guillian Barre Syndrome was the most common referral diagnosis. 11 (27.5%) children had leucopenia with lymphocytic response and 16 (40%) had thrombocytopenia. CRP was negative in 32 (80%). CPK was markedly elevated (more than 1000 IU/l) in 18 (45%) and more than 500 IU/l in 11 (27.5%) remaining between 200 to 500 IU/l. Associated features were hepatitis (elevated SGOT & SGPT) in 28 (70%) and shock in 5 (12.5%). Serological test were indicative of dengue virus (Elisa PAN BIO) in 20 (50%) of which 8 (25%) were primary dengue and 12 (30%) were secondary dengue. The outcome of therapy mainly supportive were excellent. Benign acute myositis occurs often in association with viral infection. In the present study, Dengue virus was positive in 20 (50%) children. Benign acute myositis can be differentiated from more serious causes of walking difficulty by presence of calf and thigh muscle tenderness on stretching, normal power and deep tendon reflex and elevated CPK.

  4. Benign pneumatosis in children

    Energy Technology Data Exchange (ETDEWEB)

    Fenton, L.Z.; Buonomo, C. [Department of Radiology, Children' s Hospital, Boston, MA (United States)

    2000-11-01

    Background. In pediatrics, pneumatosis intestinalis (PI) is usually due to necrotizing enterocolitis in premature newborns. Beyond infancy, PI is uncommon. ''Benign pneumatosis'' is PI in patients with few or no symptoms that resolves with conservative management. Objective. Our goal was to better characterize benign PI in children. Our investigation focused on identifying underlying risk factors, symptoms at time of diagnosis, management and outcome. Materials and methods. Available medical records and radiographs of children with pneumatosis intestinalis from 1990 to 1998 were reviewed for underlying conditions, symptoms at time of radiographs, management and outcome. Results. Thirty-seven children (mean age 4 years) were included. Thirty-two children had identifiable risk factors. Twenty -five children were immunocompromised by their underlying conditions or therapeutic regimen. Thirty-five children were managed conservatively with resolution of PI. Two patients, however, required surgery and one patient died. Conclusion. Benign pneumatosis does occur in children. The majority have underlying risk factors, most commonly related to immunosuppression. Clinical deterioration is the most useful indicator for surgical intervention. In most patients PI resolves with conservative management. (orig.)

  5. Multiple stab wounds: understanding the manner of death through the psychological autopsy.

    Science.gov (United States)

    Di Vella, G; Grattagliano, I; Curti, S; Catanesi, R; Sullivan, M K; Tattoli, L

    2017-01-01

    A 48-year-old physical therapist with no history of psychiatric disorders or suicidal tendencies was found dead by his relatives inside his apartment. Multiple stab wounds were present on the chest and the abdomen. Several more superficial cuts were also seen on the neck and the left wrist. At the death scene, there was a large pool of blood in the room, with secondary droplets and stains; a kitchen knife was found beside the body, and a suicide note on a table. Especially the number of wounds raised strong suspicion of a homicide in the first instance but some circumstances (the farewell letter, the absence of clothing injuries, no signs of third-party involvement) and autopsy findings (absence of defense or blunt injuries, the localization of the wounds, the presence of hesitation marks) pointed toward a suicide etiology. Because of the many stab injuries and the lack of a psychiatric history, further forensic investigations were required including a so-called psychological autopsy. This case report highlights that only a comprehensive interpretation of all the elements (circumstances, the scene of death, autopsy findings, and psychological autopsy) can lead to the correct solution of atypical cases of suicide.

  6. An analysis of predictors of morbidity after stab wounds of the pancreas in 78 consecutive injuries.

    Science.gov (United States)

    Krige, J E J; Kotze, U K; Sayed, R; Navsaria, P H; Nicol, A J

    2014-09-01

    Penetrating injuries of the pancreas may result in serious complications. This study assessed the factors influencing morbidity after stab wounds of the pancreas. A retrospective univariate cohort analysis was carried out of 78 patients (74 men) with a median age of 26 years (range: 16-62 years) with stab wounds of the pancreas between 1982 and 2011. The median revised trauma score (RTS) was 7.8 (range: 2.0-7.8). Injuries involved the body (n=36), tail (n=24), head/uncinate process (n=16) and neck (n=2) of the pancreas. All 78 patients underwent a laparotomy. Sixty-five patients had AAST (American Association for the Surgery of Trauma) grade I or II pancreatic injuries and thirteen had grade III, IV or V injuries. Eight patients (10.3%) had an initial damage control operation. Sixty-nine patients (84.6%) had drainage of the pancreas only, six had a distal pancreatectomy and one had a pancreaticoduodenectomy. Most pancreas related complications occurred in patients with AAST grade III injuries; eight patients (10.2%) developed a pancreatic fistula. Four patients (5.1%) died. Grade of pancreatic injury (AAST grade I-II vs grade III-V injuries, pwound, morbidity was high. Increasing AAST grade of injury, high RTS, shock on admission to hospital, need for blood transfusion and repeat laparotomy were significant factors related to morbidity.

  7. 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.

  8. Radiotherapy of benign diseases

    International Nuclear Information System (INIS)

    Haase, W.

    1982-01-01

    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 sudoriparous abscesses, degenerative skeletal diseases, cervical syndrome and others; 2. rheumatic joint diseases; 3. Bechterew's disease; 4. primary presenile osteoporosis; 5. synringomyelia; 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. (MG) [de

  9. Reduced detonation kinetics and detonation structure in one- and multi-fuel gaseous mixtures

    Science.gov (United States)

    Fomin, P. A.; Trotsyuk, A. V.; Vasil'ev, A. A.

    2017-10-01

    Two-step approximate models of chemical kinetics of detonation combustion of (i) one-fuel (CH4/air) and (ii) multi-fuel gaseous mixtures (CH4/H2/air and CH4/CO/air) are developed for the first time. The models for multi-fuel mixtures are proposed for the first time. Owing to the simplicity and high accuracy, the models can be used in multi-dimensional numerical calculations of detonation waves in corresponding gaseous mixtures. The models are in consistent with the second law of thermodynamics and Le Chatelier’s principle. Constants of the models have a clear physical meaning. Advantages of the kinetic model for detonation combustion of methane has been demonstrated via numerical calculations of a two-dimensional structure of the detonation wave in a stoichiometric and fuel-rich methane-air mixtures and stoichiometric methane-oxygen mixture. The dominant size of the detonation cell, determines in calculations, is in good agreement with all known experimental data.

  10. Precursors in detonations in porous explosives

    International Nuclear Information System (INIS)

    Spaulding, R.L. Jr.

    1981-01-01

    Photographs of detonation waves in low-density HMX and PETN, made with an image-intensifier camera, show a brilliant band of light in front of the pressure jump. The radiation temperature is estimated to be 12,000 to 14,000 0 K. The spectrum of this light is continuous. A quartz gauge shows a gradual buildup of pressure from the material producing the light. The material has little effect on the propagation of detonation. Further observations, using pellets of plastic-bonded HMX and single crystals of PETN, show that the material thrown off the free surface is transparent, with a leading edge moving at approximately 20 mm/μs. Collision of this material with polymethyl methacrylate (PMMA) produces a brilliant light with a spectrum that is initially a narrow H/sub α/ line. Quartz gauges measure the rate of pessure buildup of this material

  11. Cookoff of non-traditional detonators

    Science.gov (United States)

    Zucker, Jonathan; Tappan, Bryce C.; Manner, Virginia W.; Novak, Alan

    2012-03-01

    Significant work has gone into understanding the cookoff behavior of a variety of explosives, primarily for safety and surety reasons. However, current times require similar knowledge on a new suite of explosives that are readily attainable or made, and are easily initiated without expensive firesets or controlled materials. Homemade explosives (HMEs) are simple to synthesize from readily available precursor materials. Two of these HMEs, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) are not only simple to prepare, but have sufficient output and sensitivity to act as primary explosives in an initiation train. Previous work has shown that detonators may be an integral vulnerability in a cookoff scenario. This poster contains the results of cookoff experiments performed on detonators made with TATP and HMTD. We found that the less chemically stable TATP decomposed during heating, while the more chemically stable HMTD acted like a traditional primary explosive, namely reaction violence and time-to-ignition were independent of confinement.

  12. Detonation Shock Dynamics of Composite Energetic Materials.

    Science.gov (United States)

    Lee, Jaimin

    1990-01-01

    A reaction-rate equation for a composite energetic material was calibrated from two-dimensional steady-state experiment data by using the detonation shock dynamics theory. From experimental detonation velocities and shock -front shapes at different diameters for an ammonium nitrate -based emulsion explosive at 1.248 g/cm^3, the relationship between the detonation velocity normal to the shock-front and the shock-front curvature was obtained. By using this relationship and solving the quasi one-dimensional Euler equations of motion in a problem -conforming intrinsic-coordinate frame obtained from the detonation shock dynamics theory, the reaction rate was determined as a function of pressure and density: {dlambdaover dt} = 20.0 times 10^6 {rm exp}({-}14390/ sqrt{P/rho^{0.8418}})(1 - lambda)^{1.889}where lambda is the reaction extent, t is the time in s, P is the pressure in Pa, and rho is the density in kg/m^3 . The reaction-rate equation obtained for this emulsion explosive shows that the rate is very slow and weakly state dependent. These characteristics of the rate indicated that the nonideal behavior of most industrial-type explosives can be attributed to their slow and state-insensitive rates. By using the above rate equation, one-dimensional initiation experiments (wedge tests) were numerically modeled with a one-dimensional Lagrangian hydrodynamic code. The calculated shock trajectories agreed very well with experimental wedge test data. This agreement also suggested that the small shock-curvature asymptotics may be valid even for a relatively large value of the curvature. The calibration method developed in this study is independent of the form of the rate. Realistic rate equations for explosives can be obtained in a very systematic way from two-dimensional steady-state experiments.

  13. Simple Model for Detonation Energy and Rate

    Science.gov (United States)

    Lauderbach, Lisa M.; Souers, P. Clark

    2017-06-01

    A simple model is used to derive the Eyring equation for the size effect and detonation rate, which depends on a constant energy density. The rate derived from detonation velocities is then converted into a rate constant to be used in a reactive flow model. The rate might be constant if the size effect curve is straight, but the rate constant will change with the radius of the sample and cannot be a constant. This is based on many careful cylinder tests have been run recently on LX-17 with inner copper diameters ranging from 12.7 to 101.6 mm. Copper wall velocities at scaled displacements of 6, 12.5 and 19 mm equate to values at relative volumes of 2.4, 4.4 and 7.0. At each point, the velocities from 25.4 to 101.6 mm are constant within error whereas the 12.7 mm velocities are lower. Using the updated Gurney model, the energy densities at the three larger sizes are also constant. Similar behavior has been seen in LX-14, LX-04, and an 83% RDX mix. A rough saturation has also been in old ANFO data for diameters of 101.6 mm and larger. Although the energy densities saturate, the detonation velocities continue to increase with size. These observations suggest that maximum energy density is a constant for a given explosive of a given density. The correlation of energy density with detonation velocity is not good because the latter depends on the total energy of the sample. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. VELOCITY OF DETONATION OF LOW DENSITY

    OpenAIRE

    Vinko Škrlec; Vječislav Bohanek; Zvonimir Deković

    2012-01-01

    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 e...

  15. Pulse Detonation Rocket Magnetohydrodynamic Power Experiment

    Science.gov (United States)

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

    2003-01-01

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

  16. Insensitive detonator apparatus for initiating large failure diameter explosives

    Science.gov (United States)

    Perry, III, William Leroy

    2015-07-28

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

  17. Radio controlled detonators and sequential real time blast applications

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, T.; Laboz, J.M. [Delta Caps International, Nice (France)

    1995-12-31

    Among the numerous technical evolutions in the blasting environment the authors are going to describe below the concept of electronic detonator sequenced by radio waves, and also its numerous applications. Three major technologies are used in the initiation environment: fused-initiated detonators; electric detonators; and non-electric detonators. The last two technologies were made available under multiple variants. Two major innovations are going to substantially change the way traditional detonators operate: pyrotechnic delays are replaced by electronic delays (greater accuracy); and triggering orders, passing through a cable, is now replaced by radio-waves transmission (possibility to do real time delay pattern). Such a new product provided all the features offered by current detonators, but also allows mastering specific cases that were difficult to control with the current technology, such as: vibration control; underground blast; and building demolition.

  18. Benign fibroosseous lesions

    Directory of Open Access Journals (Sweden)

    Cansu Köseoğlu Seçgin

    2016-05-01

    Full Text Available Benign fibroosseous lesions represent a group of lesions that share the same basic evolutive mechanism and are characterized by replacement of normal bone with a fibrous connective tissue that gradually undergoes mineralization. These lesions are presented by a variety of diseases including developmental, reactive-dysplastic processes and neoplasms. Depending on the nature and amount of calcified tissue, they can be observed as radiolucent, mixed or radiopaque. Their radiographic features could be well-defined or indistinguishable from the surrounding bone tissue. They can be asymptomatic as in osseous dysplasias and can be detected incidentally on radiographs, or they can lead to expansion in the affected bone as in ossifying fibroma. All fibroosseous lesions seen in the jaws and face are variations of the same histological pattern. Therefore, detailed clinical and radiographic evaluation in differential diagnosis is important. In this review, fibroosseous benign lesions are classified as osseous dysplasia, fibrous dysplasia and fibroosseous tumors; and radiographic features and differential diagnosis of these lesions are reviewed taking into account this classification.

  19. Detonation Shock Dynamics Modelling with Arbitrary Boundaries

    Science.gov (United States)

    Hodgson, Alexander

    2017-06-01

    The Detonation Shock Dynamics (DSD) model can be used to predict detonation wave propagation in a high explosive (HE). The detonation wave is prescribed a velocity that depends on its curvature. Additionally, the angle between the wave and the HE boundary may not exceed a specified ``boundary angle'', the value of which depends on the HE and its confining material(s). The level-set method is commonly used to drive DSD computation. Boundary conditions are applied to the level-set field at the charge edges to maintain the explosive boundary angle criteria. The position of the boundary must be accurate and continuous across adjacent cells to achieve accurate and robust results. This is mainly an issue for mixed material meshes where the boundary does not coincide with the cell boundaries. For such meshes, a set of volume fractions defines the amount of material in each cell. The boundary is defined implicitly by the volume fractions, and must be reconstructed to an explicit form for use in DSD. This work describes a novel synthesis of the level-set method and simulated annealing, an optimisation method used to reconstruct the boundary. The accuracy and robustness of the resulting DSD calculation are evaluated with a range of test problems.

  20. Detonation Performance Analyses for Recent Energetic Molecules

    Science.gov (United States)

    Stiel, Leonard; Samuels, Philip; Spangler, Kimberly; Iwaniuk, Daniel; Cornell, Rodger; Baker, Ernest

    2017-06-01

    Detonation performance analyses were conducted for a number of evolving and potential high explosive materials. The calculations were completed for theoretical maximum densities of the explosives using the Jaguar thermo-chemical equation of state computer programs for performance evaluations and JWL/JWLB equations of state parameterizations. A number of recently synthesized materials were investigated for performance characterizations and comparisons to existing explosives, including TNT, RDX, HMX, and Cl-20. The analytic cylinder model was utilized to establish cylinder and Gurney velocities as functions of the radial expansions of the cylinder for each explosive. The densities and heats of formulation utilized in the calculations are primarily experimental values from Picatinny Arsenal and other sources. Several of the new materials considered were predicted to have enhanced detonation characteristics compared to conventional explosives. In order to confirm the accuracy of the Jaguar and analytic cylinder model results, available experimental detonation and Gurney velocities for representative energetic molecules and their formulations were compared with the corresponding calculated values. Close agreement was obtained with most of the data. Presently at NATO.

  1. 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.

  2. Characterizing detonator output using dynamic witness plates

    International Nuclear Information System (INIS)

    Murphy, Michael John; Adrian, Ronald J.

    2009-01-01

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

  3. Benign cementoblastoma: A case report

    Directory of Open Access Journals (Sweden)

    Sitapathi Revathi

    2016-03-01

    Full Text Available Benign cementoblastoma is a rare odontogenic tumor of mesenchymal origin comprising only less than 1% of all odontogenic tumors. The radiographic features is very characteristic in which the tumor mass is attached to the root of the tooth. Histopathologically benign cementoblastoma and osteoblastoma are indistinguishable. Here, a case report of 28 year old patient with benign cementoblastoma is presented along with a brief review of literature.

  4. Radiation therapy of benign diseases

    International Nuclear Information System (INIS)

    Order, S.E.; Donaldson, S.

    1990-01-01

    This book reports on the evaluation and treatment of benign disease. The text begins with a chapter concerning standards of practice by an eminent malpractice lawyer, thereby clarifying the medical-legal implications of the radiation treatment of benign disease. The text then lists, in alphabetic order, those benign diseases which have been or are currently treated with radiotherapy for each disease entity. A feature is the survey of current radiation practice in the United States

  5. Three Dimensional Analysis of Induced Detonation of Cased Explosive

    Science.gov (United States)

    2014-10-16

    armour (RHA) steel were investigated through the LS-DYNA. The investigation focused on shock to detonation simulations of Composition B, with the...casing of the explosive leading to the so-called sympathetic detonation . At high impact velocity, initiation of the explosive was caused by the...analytical equations for a sphere and an indefinitely long cylinder. In general, the impact shock induced detonation behavior of an explosive is

  6. Explosives malfunction from sympathetic detonation to shock desensitization

    Energy Technology Data Exchange (ETDEWEB)

    Katsabanis, P.D.; Yeung, C.; Fitz, G.; Heater, R. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Mining Engineering

    1994-12-31

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

  7. Detonation Velocity Measurement with Chirped Fiber Bragg Grating

    OpenAIRE

    Wei, Peng; Lang, Hao; Liu, Taolin; Xia, Dong

    2017-01-01

    Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG...

  8. [Gunshot and stab wounds in Germany--epidemiology and outcome: analysis from the TraumaRegister DGU®].

    Science.gov (United States)

    Bieler, D; Franke, A F; Hentsch, S; Paffrath, T; Willms, A; Lefering, R; Kollig, E W

    2014-11-01

    The management of gunshot wounds is a rare challenge for trauma surgeons in Germany and Central Europe as a result of the low incidence of this type of trauma. Penetrating injuries occur with an incidence of 5% in Germany. They are caused by gunshots or more commonly by knives or other objects, for example during accidents. Since even the number of patients who are treated at level 1 trauma centres is limited by the low incidence, the objective of this study was to assess the epidemiology and outcome of gunshot and stab wounds in Germany. Since 2009, the trauma registry of the German Trauma Society (TraumaRegister DGU®) has been used to assess not only whether a trauma was penetrating but also whether it was caused by a gunshot or a stabbing. On the basis of this registry, we identified relevant cases and defined the observation period. Data were taken from the standard documentation forms that participating German hospitals completed between 2009 and 2011. We did not specify exclusion criteria in order to obtain as comprehensive a picture as possible of the trauma entities investigated in this study. As a result of the high incidence of gunshot wounds to the head and the implications of this type of injury for the entire group, a subgroup of patients without head injuries was analysed. From 2009 to 2011, there were 305 patients with gunshot wounds and 871 patients with stab wounds. The high proportion of suicide-related gunshot wounds to the head resulted in a cumulative mortality rate of 39.7%. Stab wounds were associated with a lower mortality rate (6.2%). Every fourth patient with a gunshot or stab wound presented with haemorrhagic shock, which was considerably more frequently seen during the prehospital phase than during the inhospital phase of patient management. Of the patients with gunshot wounds, 26.9% required transfusions. This percentage was three times higher than that for patients with blunt trauma. In Germany, gunshot and stab wounds have a low

  9. An audit of failed non-operative management of abdominal stab wounds.

    Science.gov (United States)

    Clarke, D L; Allorto, N L; Thomson, S R

    2010-05-01

    Selective non-operative management based on clinical assessment has been shown to be a generally safe approach in the management of penetrating stab wounds of the torso. However there will be a subset of patients who fail selective non-operative management. This audit focuses on the failures. The metropolitan surgical service in Pietermaritzburg covers 3 hospitals. At the weekly metropolitan morbidity and mortality meeting all trauma patients are reviewed. All cases of failed selective non-operative management of penetrating abdominal stab wounds are discussed. Failed non-operative management is usually defined as any patient who ultimately requires surgical exploration. We do not subscribe to this as we feel as long as the need for surgical intervention is recognised within a short period of time (wound were managed over the 2 year period under review. A total of 192 (56%) of these patients were subjected to mandatory laparotomy. Of these mandatory laparotomies 98% were positive. The remaining 148 (44%) patients were observed. Of the 148 observed patients a total of 30 (20%) subsequently underwent surgery. A total of 13 patients were only taken to surgery after 12h of observation. In this group of 13 patients the average delay between admission and recognition of injury was 40 h. There were six gastric injuries, one pyloric and pancreatic injury, two gallbladder injuries, one liver, one colon and two small bowel injuries. There were no deaths. 9 patients recovered with no additional morbidity. In the remainder, morbidity included, relaparotomy (1), open abdomen (1), renal failure (1) and prolonged stay in ICU (3). Clinical assessment accurately predicts the need for mandatory laparotomy following a stab wound to the torso. In patients who do not meet the indications for mandatory laparotomy and who are subjected to non-operative management 20% will come to surgery. A subgroup may only be recognised as requiring surgery after more than 12h. These patients are at

  10. Laparoscopic diagnostic peritoneal lavage (L-DPL: A method for evaluation of penetrating abdominal stab wounds

    Directory of Open Access Journals (Sweden)

    Krausz Michael M

    2006-03-01

    Full Text Available Abstract Background The management of penetrating abdominal stab wounds has been the subject of continued reappraisal and controversy. In the present study a novel method which combines the use of diagnostic laparoscopy and DPL, termed laparoscopic diagnostic peritoneal lavage (L-DPL is described Method Five trauma patients with penetrating injuries to the lower chest or abdomen were included. Standard videoscopic equipment is utilized for the laparoscopic trauma evaluation of the injured patient. When no significant injury is detected, the videoscope is withdrawn and 1000 mL of normal saline is infused through the abdominal trochar into the peritoneal cavity, and the effluent fluid studied for RBCs, WBC, amylase debry, bile as it is uced in regular diagnostic peritoneal lavage Results Laparoscopic peritoneal lavage (L-DPL was then performed and proved to be negative in all 5 patients. RBC lavage counts above 100,000/mcrl were not considered as a positive lavage result, because the bleeding source was directly observed and controlled laparoscopically. All patients recovered uneventfully and were released within 3 days. This procedure combines the visual advantages of laparoscopy together with the sensitivity and specificty of DPL for the diagnosis of significant penetrating intra-abdominal injury, when the diagnostic strategy of selective consevatism for abdominal stab wounds is adopted. Conclusion A method of laparoscopic diagnostic peritoneal lavage (L-DPL in hemodynamically stable patients with penetrating lower thoracic or abdominal stab wounds is described. The method is especially applicable for trauma surgeons with only basic experience in laparoscopic technique. This procedure is used to obtain conclusive evidence of significant intra-abdominal injury, confirm peritoneal penetration, control intra-abdominal bleeding, and repair lacerations to the diaphragm and abdominal wall. The combination of laparoscopy and DPL afforded by the L

  11. A comparison of methods for detonation pressure measurement

    Science.gov (United States)

    Pachman, J.; Künzel, M.; Němec, O.; Majzlík, J.

    2018-03-01

    Detonation pressure is an important parameter describing the process of detonation. The paper compares three methods for determination of detonation pressure on the same explosive charge design. Pressed RDX/wax pellets with a density of 1.66 g cm^{-3} were used as test samples. The following methods were used: flyer plate method, impedance window method, and detonation electric effect. Photonic Doppler velocimetry was used for particle velocity measurements in the first two cases. The outputs of the three methods are compared to the literature values and to thermochemical calculation predictions.

  12. Response Surface Optimization of Lead Azide for Explosive Detonators

    National Research Council Canada - National Science Library

    McCulloh, Ian; Massie, Darrell; Cordaro, Emily

    2006-01-01

    The Armament Research, Development and Engineering Center, Picatinny (ARDEC) has been tasked with developing a new chemical process to produce lead azide, the key explosive ingredient in detonators...

  13. Hydroxyapatite Reinforced Coatings with Incorporated Detonationally Generated Nanodiamonds

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  14. 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.

  15. 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.

  16. 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.

  17. Deflagration to detonation transition in thermonuclear supernovae

    International Nuclear Information System (INIS)

    Charignon, Camille

    2013-01-01

    Type Ia supernovae are an important tool to determine the expansion history of our Universe. Thus, considerable attention has been given to both observations and models of these events. The most popular explosion model is the central ignition of a deflagration in the dense C+O interior of a Chandrasekhar mass white dwarf, followed by a transition to a detonation (TDD). We study in this thesis a new mechanism for this transition. The most robust and studied progenitor model and the postulated mechanism for the TDD, the so called 'Zel'dovich gradient mechanism', are presented. State of the art 3D simulations of such a delayed detonation, at the price of some adjustments, can indeed reproduce observables. But due to largely unresolved physical scales, such simulations cannot explain the TDD by themselves, and especially, the physical mechanism which triggers this transition - which is not yet understood, even on Earth, for unconfined media. It is then discussed why the current Zel'dovich mechanism might be too constraining for a SN Ia model, pointing to a new approach, which is the core result of this thesis.In the final part, our alternative model for DDT in supernovae, the acoustic heating of the pre-supernova envelope, is presented. A planar model first proves that small amplitude acoustic perturbations (generated by a turbulent flame) are actually amplified in a steep density gradient, up to a point where they turn into shocks able to trigger a detonation. Then, this mechanism is applied to more realistic models, taking into account, in spherical geometry, the expanding envelope. A parametric study demonstrates the validity of the model for a reasonable range of acoustic wave amplitudes and frequencies.To conclude, some exploratory 2D and 3D MHD simulations, seeking for realistic acoustic source compatible with our mechanism, are presented. (author) [fr

  18. Numerical computation of linear instability of detonations

    Science.gov (United States)

    Kabanov, Dmitry; Kasimov, Aslan

    2017-11-01

    We propose a method to study linear stability of detonations by direct numerical computation. The linearized governing equations together with the shock-evolution equation are solved in the shock-attached frame using a high-resolution numerical algorithm. The computed results are processed by the Dynamic Mode Decomposition technique to generate dispersion relations. The method is applied to the reactive Euler equations with simple-depletion chemistry as well as more complex multistep chemistry. The results are compared with those known from normal-mode analysis. We acknowledge financial support from King Abdullah University of Science and Technology.

  19. Velocity of detonation-a mathematical model.

    Science.gov (United States)

    Türker, Lemi

    2010-06-01

    Based on the principles of conservation of energy and momentum, a mathematical formula has been derived for the squares of detonation velocities of a large set of explosives. The equation is a function of the total energy and molecular weight of an explosive compound considered. A regressed equation has been obtained for a pool of explosives of various types including nitramines, aliphatic and aromatic nitro compounds. Also another regressed equation for nitramines only is given. For the regression, the total energies are obtained using DFT (UB3LYP/6-31G(d)). The regression statistics are given and discussed.

  20. 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.

  1. Laser image recording on detonation nanodiamond films

    International Nuclear Information System (INIS)

    Mikheev, G M; Mikheev, K G; Mogileva, T N; Puzyr, A P; Bondar, V S

    2014-01-01

    A focused He – Ne laser beam is shown to cause local blackening of semitransparent detonation nanodiamond (DND) films at incident power densities above 600 W cm -2 . Data obtained with a Raman spectrometer and low-power 632.8-nm laser source indicate that the blackening is accompanied by a decrease in broadband background luminescence and emergence of sharp Raman peaks corresponding to the structures of nanodiamond and sp 2 carbon. The feasibility of image recording on DND films by a focused He – Ne laser beam is demonstrated. (letters)

  2. Laser image recording on detonation nanodiamond films

    Energy Technology Data Exchange (ETDEWEB)

    Mikheev, G M; Mikheev, K G; Mogileva, T N [Institute of Mechanics, Ural Branch of the Russian Academy of Sciences, Izhevsk (Russian Federation); Puzyr, A P; Bondar, V S [Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences (Russian Federation)

    2014-01-31

    A focused He – Ne laser beam is shown to cause local blackening of semitransparent detonation nanodiamond (DND) films at incident power densities above 600 W cm{sup -2}. Data obtained with a Raman spectrometer and low-power 632.8-nm laser source indicate that the blackening is accompanied by a decrease in broadband background luminescence and emergence of sharp Raman peaks corresponding to the structures of nanodiamond and sp{sup 2} carbon. The feasibility of image recording on DND films by a focused He – Ne laser beam is demonstrated. (letters)

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

    Science.gov (United States)

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

    2006-07-01

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

  4. Cellular detonations in nano-sized aluminum particle gas suspensions

    Science.gov (United States)

    Khmel, TA

    2017-10-01

    Formation of cellular detonation structures in monodisperse nano-sized aluminum particle – oxygen suspensions is studied by methods of numerical simulations of two-dimensional detonation flows. The detonation combustion are described within the semi-empirical model developed earlier which takes into account transition of the regime of aluminum particle combustion from diffusion to kinetic for micro-sized and nano-sized particles. The free-molecular effects are considered in the processes of heat and velocity relaxation of the phases. The specific features of the cellular detonation of nanoparticle suspensions comparing with micron-sized suspensions are irregular cellular structures, much higher pick pressure values, and relatively larger detonation cells. This is due to high value of activation energy of reduced chemical reaction of aluminum particle combustion in kinetic regime.

  5. Measuring In-Situ Mdf Velocity Of Detonation

    Science.gov (United States)

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

    2005-10-25

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

  6. 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.

  7. Equations of state for explosive detonation products: The PANDA model

    Energy Technology Data Exchange (ETDEWEB)

    Kerley, G.I.

    1994-05-01

    This paper discusses a thermochemical model for calculating equations of state (EOS) for the detonation products of explosives. This model, which was first presented at the Eighth Detonation Symposium, is available in the PANDA code and is referred to here as ``the Panda model``. The basic features of the PANDA model are as follows. (1) Statistical-mechanical theories are used to construct EOS tables for each of the chemical species that are to be allowed in the detonation products. (2) The ideal mixing model is used to compute the thermodynamic functions for a mixture of these species, and the composition of the system is determined from assumption of chemical equilibrium. (3) For hydrocode calculations, the detonation product EOS are used in tabular form, together with a reactive burn model that allows description of shock-induced initiation and growth or failure as well as ideal detonation wave propagation. This model has been implemented in the three-dimensional Eulerian code, CTH.

  8. 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.

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

    Science.gov (United States)

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

    2015-05-01

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

  10. Numerical Model of Detonation for Insensitive HE

    Science.gov (United States)

    Klimenko, Vladimir

    2011-06-01

    Most of modern munitions are filled by insensitive HE. However, mechanism of initiation of these HE is still unknown. IHE have not any pores and, therefore, hot spot mechanism does not work here. What is a mechanism working in this case? We have used 3D hydrocode to study process of shock wave loading of mixture of HMX grains with different binders (HMX/binder=88/12) and have determined formation of surface layers with increased plastic deformation. According to the dislocation mechanism of detonation (V. Klimenko, I. Kozyreva, J. Energetic Materials, 2010, v. 28, pp. 249-262) plastic deformation generates definite concentration of radicals. Surface layers have also increased temperature due to viscous work. So, these activated layers have increased temperature and number of radicals in comparison with values inside grains. Kinetic calculation has shown fast decomposition of these layers. As a result, the activated layer is ignited and this gives beginning of grain burning process. The developed two-stages mechanism has been incorporated into 2D hydrocode. The developed numerical model demonstrates high accuracy in simulation of detonation processes in IHE (in particular, PBXN-110 and B2241).

  11. 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

  12. 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. .

  13. Multiple self-inflicted stab wounds to neck, chest and abdomen as a unique manner of suicide.

    Science.gov (United States)

    Kaliszan, Michał; Kernbach-Wighton, Gerhard; Bouhaidar, Ralph

    2010-05-01

    This is a case report of a 30-year-old man found dead in his flat lying on the floor with multiple stab wounds over the body, surrounded by an extensive volume of blood. Examination of the scene of death showed a secure flat, locked from inside. A blood-stained knife was present close to the body and two unstained notes left on the sofa at the locus. A small plastic bag containing white powder (which following toxicological examinations appeared to be cocaine) and an almost full bottle of beer were present on a table. Autopsy revealed more than 40 stab wounds to neck, chest, and abdomen arranged in isolated groups within which the wounds showed similar directions and had a transverse orientation. Together with hesitation marks located on the neck and wrists these characteristics allowed to interpret this case as a suicide.

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

    OpenAIRE

    Kimura, Kazuki; Chiba, Satoshi

    2015-01-01

    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 rec...

  15. 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: ...

  16. Benign bone-forming tumors

    International Nuclear Information System (INIS)

    Heuck, A.; Staebler, A.; Steinborn, M.; Woertler, K.

    2001-01-01

    Benign bone-forming tumors include osteomas, enostomas, osteoid osteomas, and osteoblastomas. These lesions are often characterized by typical imaging findings on radiographs, CT and MR imaging studies. Radiologic findings and additional clinical information allow for a specific diagnosis in most cases. This review article emphasizes the radiological patterns of benign boneforming tumors as well as their epidemiological, clinical, and pathological characteristics. In addition, minimally invasive interventional procedures for the therapy of osteoid osteoma are reviewed. (orig.) [de

  17. Comparison between isolated serial clinical examination and computed tomography for stab wounds in the anterior abdominal wall.

    Science.gov (United States)

    Breigeiron, Ricardo; Breitenbach, Tiago Cataldo; Zanini, Lucas Adalberto Geraldi; Corso, Carlos Otavio

    2017-01-01

    to compare abdominal computer tomography (CT) with isolated serial clinical exam (SCE) in the management of anterior abdominal stab wounds. randomized prospective study performed at Hospital de Pronto Socorro de Porto Alegre involving patients with anterior abdominal stab wounds without indication of immediate laparotomy; patients were divided in two groups: CT group and SCE group, In the SCE group, patients were followed up with serial clinical exam every 6 hours, Patients of CT group were submitted to abdominal computer tomography after initial evaluation. 66 patients were studied and 33 were included in each group, Of total, six were submitted to surgery, three of each group, In the SCE group, patients submitted to surgery in media waited 12 hours from arrival to diagnosis without any non-therapeutic surgeries, The remaining 30 patients of this group were discharged from hospital after 24 hours of observation, In the CT group, three patients showed alteration at CT and were submitted to laparotomy, one non-therapeutic, The others were discharged from hospital after 24 hours of observation, Abdominal computer tomography had a positive predictive value (PPV) of 67% and negative predictive value (NPV) of 100%, with 96% of accuracy, Isolated serial clinical exam showed PPV and NPV of 100% and 100% of accuracy. selective management of anterior abdominal stabs is safe, when a rigorous selection of patients is observed, Isolated serial clinical exam may be performed without computer tomography, without increase of hospitalization time or morbidity, reducing costs, exposure to radiation, mortality and morbidity and non-therapeutic laparotomies.

  18. Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

    Science.gov (United States)

    Cole, Lord Kahil

    A number of promising alternative rocket propulsion concepts have been developed over the past two decades that take advantage of unsteady combustion waves in order to produce thrust. These concepts include the Pulse Detonation Rocket Engine (PDRE), in which repetitive ignition, propagation, and reflection of detonations and shocks can create a high pressure chamber from which gases may be exhausted in a controlled manner. The Pulse Detonation Rocket Induced Magnetohydrodynamic Ejector (PDRIME) is a modification of the basic PDRE concept, developed by Cambier (1998), which has the potential for performance improvements based on magnetohydrodynamic (MHD) thrust augmentation. The PDRIME has the advantage of both low combustion chamber seeding pressure, per the PDRE concept, and efficient energy distribution in the system, per the rocket-induced MHD ejector (RIME) concept of Cole, et al. (1995). In the initial part of this thesis, we explore flow and performance characteristics of different configurations of the PDRIME, assuming quasi-one-dimensional transient flow and global representations of the effects of MHD phenomena on the gas dynamics. By utilizing high-order accurate solvers, we thus are able to investigate the fundamental physical processes associated with the PDRIME and PDRE concepts and identify potentially promising operating regimes. In the second part of this investigation, the detailed coupling of detonations and electric and magnetic fields are explored. First, a one-dimensional spark-ignited detonation with complex reaction kinetics is fully evaluated and the mechanisms for the different instabilities are analyzed. It is found that complex kinetics in addition to sufficient spatial resolution are required to be able to quantify high frequency as well as low frequency detonation instability modes. Armed with this quantitative understanding, we then examine the interaction of a propagating detonation and the applied MHD, both in one-dimensional and two

  19. Chemical kinetics of detonation in some liquid mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Raikova, Vlada M.; Likholatov, Evgeny A. [Mendeleev University of Chemical Technology, Moscow (Russian Federation)

    2005-09-01

    The main objective of this work is to study the chemical kinetics of detonation reactions in some nitroester mixtures and solutions of nitrocompounds in concentrated nitric acid. The main source of information on chemical kinetics in the detonation wave was the experimental dependence of failure diameter on composition of mixtures. Calculations were carried out in terms of classic theory of Dremin using the SGKR computer code. Effective values for the activation energies and pre-exponential factors for detonation reactions in the mixtures under investigation have been defined. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  20. 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.

  1. A new method of ergonomic testing of gloves protecting against cuts and stabs during knife use.

    Science.gov (United States)

    Irzmańska, Emilia; Tokarski, Tomasz

    2017-05-01

    The paper presents a new method of ergonomic evaluation of gloves protecting against cuts and stabs during knife use, consisting of five manual dexterity tests. Two of them were selected based on the available literature and relevant safety standards, and three were developed by the authors. All of the tests were designed to simulate occupational tasks associated with meat processing as performed by the gloved hand in actual workplaces. The tests involved the three most common types of protective gloves (knitted gloves made of a coverspun yarn, metal mesh gloves, and metal mesh gloves with an ergonomic polyurethane tightener) and were conducted on a group of 20 males. The loading on the muscles of the upper limb (adductor pollicis, flexor carpi ulnaris, flexor carpi radialis, and biceps brachii) was measured using surface electromyography. For the obtained muscle activity values, correlations were found between the glove type and loading of the upper limb. ANOVA showed that the activity of all muscles differed significantly between the five tests. A relationship between glove types and electromyographic results was confirmed at a significance level of α = 0.05. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. [Forensic medical expertise of the stab wounds: the current state-of-the art].

    Science.gov (United States)

    Sarkisian, B A; Karpov, D A

    2014-01-01

    This review of special literature encompasses the publications on the injuries inflicted by piercing objects. The results of analysis of these materials indicate that both the mechanisms of formation and the morphological features of stab wounds and damages to the clothes are studied perfectly well. Their shape and morphological patterns are shown to be dependent on the size, shape, and cross-section area of the great variety of the piercing objects. However, investigations carried out thus far did not take into consideration the formation of the signs of skin plastic deformation, such as edge portions of borderline thickening, stretching of epidermis over the walls, transformation of the epidermal network pattern into longitudinal folding, etc. It is concluded that further studies are necessary to better characterize injuries inflicted by piercing objects differing in the sharpness and the shape of cross section and thereby to obtain a deeper insight in the morphological features. It can be expected that such studies will provide a basis for the development of criteria for the individual and intra-group expert identification of the traumatic agents.

  3. The spectrum of injuries resulting from posterior abdominal stab wounds: a South African experience.

    Science.gov (United States)

    Kong, V Y; Oosthuizen, G V; Clarke, D L

    2015-05-01

    The spectrum of injury associated with anterior abdominal stab wounds (SWs) is well established. The literature on the spectrum of organ injury associated with SWs to the posterior abdomen, however, is limited. We reviewed our experience of 105 consecutive patients who had established indications for laparotomy managed over a 4-year period in a high volume trauma service in South Africa. Of the 105 patients, 97 (92%) were male and the overall mean age was 24 years. Fifty-seven patients (54%) had immediate indications for laparotomy. The remaining 48 patients (46%) initially underwent active clinical observation and the indications for laparotomy became apparent during the observation period. Of the 105 laparotomies performed, 94 (90%) were positive and 11 (10%) were negative. Of the 94 positive laparotomies, 92 were therapeutic and 2 were non-therapeutic. A total of 176 organ injuries were identified: 50 (53%) of the 94 patients sustained a single organ injury while the remaining 44 (47%) sustained multiple organ injuries. The most commonly injured organs were the colon (n=63), spleen (n=21) and kidney (n=19). The pattern of intra-abdominal injuries secondary to SWs to the posterior abdomen is different to that seen with the anterior abdomen. Colonic injury is most commonly encountered, followed by injuries to the spleen and kidney. Clinicians must remain vigilant because of the potential for occult injuries.

  4. Determining injuries from posterior and flank stab wounds using computed tomography tractography.

    Science.gov (United States)

    Bansal, Vishal; Reid, Chris M; Fortlage, Dale; Lee, Jeanne; Kobayashi, Leslie; Doucet, Jay; Coimbra, Raul

    2014-04-01

    Unlike anterior stab wounds (SW), in which local exploration may direct management, posterior SW can be challenging to evaluate. Traditional triple contrast computed tomography (CT) imaging is cumbersome and technician-dependent. The present study examines the role of CT tractography as a strategy to manage select patients with back and flank SW. Hemodynamically stable patients with back and flank SW were studied. After resuscitation, Betadine- or Visipaque®-soaked sterile sponges were inserted into each SW for the estimated depth of the wound. Patients underwent abdominal helical CT scanning, including intravenous contrast, as the sole abdominal imaging study. Images were reviewed by an attending radiologist and trauma surgeon. The tractogram was evaluated to determine SW trajectory and injury to intra- or retroperitoneal organs, vascular structures, the diaphragm, and the urinary tract. Complete patient demographics including operative management and injuries were collected. Forty-one patients underwent CT tractography. In 11 patients, tractography detected violation of the intra- or retroperitoneal cavity leading to operative exploration. Injuries detected included: the spleen (two), colon (one), colonic mesentery (one), kidney (kidney), diaphragm (kidney), pneumothorax (seven), hemothorax (two), iliac artery (one), and traumatic abdominal wall hernia (two). In all patients, none had negative CT findings that failed observation. In this series, CT tractography is a safe and effective imaging strategy to evaluate posterior torso SW. It is unknown whether CT tractography is superior to traditional imaging modalities. Other uses for CT tractography may include determining trajectory from missile wounds and tangential penetrating injuries.

  5. Radical Pancreaticoduodenectomy for Benign Disease

    Directory of Open Access Journals (Sweden)

    D. O. Kavanagh

    2008-01-01

    Full Text Available 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 in

  6. 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

  7. Blasting detonators incorporating semiconductor bridge technology

    Energy Technology Data Exchange (ETDEWEB)

    Bickes, R.W. Jr.

    1994-05-01

    The enormity of the coal mine and extraction industries in Russia and the obvious need in both Russia and the US for cost savings and enhanced safety in those industries suggests that joint studies and research would be of mutual benefit. The author suggests that mine sites and well platforms in Russia offer an excellent opportunity for the testing of Sandia`s precise time-delay semiconductor bridge detonators, with the potential for commercialization of the detonators for Russian and other world markets by both US and Russian companies. Sandia`s semiconductor bridge is generating interest among the blasting, mining and perforation industries. The semiconductor bridge is approximately 100 microns long, 380 microns wide and 2 microns thick. The input energy required for semiconductor bridge ignition is one-tenth the energy required for conventional bridgewire devices. Because semiconductor bridge processing is compatible with other microcircuit processing, timing and logic circuits can be incorporated onto the chip with the bridge. These circuits can provide for the precise timing demanded for cast effecting blasting. Indeed tests by Martin Marietta and computer studies by Sandia have shown that such precise timing provides for more uniform rock fragmentation, less fly rock, reduce4d ground shock, fewer ground contaminants and less dust. Cost studies have revealed that the use of precisely timed semiconductor bridges can provide a savings of $200,000 per site per year. In addition to Russia`s vast mineral resources, the Russian Mining Institute outside Moscow has had significant programs in rock fragmentation for many years. He anticipated that collaborative studies by the Institute and Sandia`s modellers would be a valuable resource for field studies.

  8. Theory of weakly nonlinear self-sustained detonations

    KAUST Repository

    Faria, Luiz

    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.

  9. 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.

  10. Laser-Supported Detonation Concept as a Space Thruster

    International Nuclear Information System (INIS)

    Fujiwara, Toshi; Miyasaka, Takeshi

    2004-01-01

    Similar to the concept of pulse detonation engine (PDE), a detonation generated in the 'combustion chamber' due to incoming laser absorption can produce the thrust basically much higher than the one that a laser-supported deflagration wave can provide. Such a laser-supported detonation wave concept has been theoretically studied by the first author for about 20 years in view of its application to space propulsion. The entire work is reviewed in the present paper. The initial condition for laser absorption can be provided by increasing the electron density using electric discharge. Thereafter, once a standing/running detonation wave is formed, the laser absorption can continuously be performed by the classical absorption mechanism called Inverse Bremsstrahlung behind a strong shock wave

  11. Development and testing of pulsed and rotating detonation combustors

    Science.gov (United States)

    St. George, Andrew C.

    Detonation is a self-sustaining, supersonic, shock-driven, exothermic reaction. Detonation combustion can theoretically provide significant improvements in thermodynamic efficiency over constant pressure combustion when incorporated into existing cycles. To harness this potential performance benefit, countless studies have worked to develop detonation combustors and integrate these devices into existing systems. This dissertation consists of a series of investigations on two types of detonation combustors: the pulse detonation combustor (PDC) and the rotating detonation combustor (RDC). In the first two investigations, an array of air-breathing PDCs is integrated with an axial power turbine. The system is initially operated with steady and pulsed cold air flow to determine the effect of pulsed flow on turbine performance. Various averaging approaches are employed to calculate turbine efficiency, but only flow-weighted (e.g., mass or work averaging) definitions have physical significance. Pulsed flow turbine efficiency is comparable to steady flow efficiency at high corrected flow rates and low rotor speeds. At these conditions, the pulse duty cycle expands and the variation of the rotor incidence angle is constrained to a favorable range. The system is operated with pulsed detonating flow to determine the effect of frequency, fill fraction, and rotor speed on turbine performance. For some conditions, output power exceeds the maximum attainable value from steady constant pressure combustion due to a significant increase in available power from the detonation products. However, the turbine component efficiency estimated from classical thermodynamic analysis is four times lower than the steady design point efficiency. Analysis of blade angles shows a significant penalty due to the detonation, fill, and purge processes simultaneously imposed on the rotor. The latter six investigations focus on fundamental research of the RDC concept. A specially-tailored RDC data

  12. Detonation Velocity Measurement with Chirped Fiber Bragg Grating.

    Science.gov (United States)

    Wei, Peng; Lang, Hao; Liu, Taolin; Xia, Dong

    2017-11-06

    Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage-time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%.

  13. Detonation Velocity Measurement with Chirped Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    Peng Wei

    2017-11-01

    Full Text Available Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage–time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%.

  14. Quasi-1 Dimensional Modeling of Rotational Detonation Engines

    Data.gov (United States)

    National Aeronautics and Space Administration — This project looks to investigate the modeling of rotational detonation engines (RDE). RDEs are an alternative engine cycle to conventional liquid rocket engines,...

  15. Evaluation of a Liquid-Fueled Pulse Detonation Engine Combustor

    National Research Council Canada - National Science Library

    Forster, David

    1998-01-01

    ... for use in the combustor. The chosen atomizer was installed in the combustor geometries and then analyzed over a range of combustor conditions to measure deflagration to detonation transition (DDT...

  16. Thermal Behaviour and Detonation Characterization of N-Benzoyl-3 ...

    African Journals Online (AJOL)

    NICO

    The apparent activation energy, pre-exponential factor and the mechanism function are 170.77 kJ mol–1, 1014.12 s–1 and f(a) = (1–a)–1/2, respec- tively. ... The detonation velocity. (D) and ... N-benzoyl-3,3-dinitroazetidine(BDNAZ), thermal behaviour, non-isothermal kinetics, thermal safety, detonation characterization. 1.

  17. Thermodynamic modelling of detonation H-N-O high explosives

    Science.gov (United States)

    Bogdanova, Yu A.; Gubin, S. A.; Anikeev, A. A.; Victorov, S. B.

    2016-09-01

    The multiphase model of a detonation products based on the equations of state (EOS) of chemically reacting H-N-O systems which is used in the thermodynamic TDS code is presented. This model is applicable over a wide range of temperatures and density. This model consists of theoretically reasonable EOS for a multicomponent gas (fluid) phase. The calculations of detonation based on the presented model to be in good agreement with experimental data.

  18. Sub-Chandrasekhar-mass White Dwarf Detonations Revisited

    Science.gov (United States)

    Shen, Ken J.; Kasen, Daniel; Miles, Broxton J.; Townsley, Dean M.

    2018-02-01

    The detonation of a sub-Chandrasekhar-mass white dwarf (WD) has emerged as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. Recent studies have suggested that the rapid transfer of a very small amount of helium from one WD to another is sufficient to ignite a helium shell detonation that subsequently triggers a carbon core detonation, yielding a “dynamically driven double-degenerate double-detonation” SN Ia. Because the helium shell that surrounds the core explosion is so minimal, this scenario approaches the limiting case of a bare C/O WD detonation. Motivated by discrepancies in previous literature and by a recent need for detailed nucleosynthetic data, we revisit simulations of naked C/O WD detonations in this paper. We disagree to some extent with the nucleosynthetic results of previous work on sub-Chandrasekhar-mass bare C/O WD detonations; for example, we find that a median-brightness SN Ia is produced by the detonation of a 1.0 {M}ȯ WD instead of a more massive and rarer 1.1 {M}ȯ WD. The neutron-rich nucleosynthesis in our simulations agrees broadly with some observational constraints, although tensions remain with others. There are also discrepancies related to the velocities of the outer ejecta and light curve shapes, but overall our synthetic light curves and spectra are roughly consistent with observations. We are hopeful that future multidimensional simulations will resolve these issues and further bolster the dynamically driven double-degenerate double-detonation scenario’s potential to explain most SNe Ia.

  19. On a stabilization mechanism for low-velocity detonations

    KAUST Repository

    Sow, Aliou

    2017-03-08

    We use numerical simulations of the reactive Lula equations to analyse the nonlinear stability of steady-state one-dimensional solutions for 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 solutions found in Semenko el al.

  20. Divergent detonation wave processes in PBX based on RDX

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Ricardo A.L.; Campos, Jose L.S. de A.; Plaksin, Igor Y.; Ribeiro, Jose M.B.M. [Fac. of Sciences and Technology of the University of Coimbra, Pinhal de Marrocos, Polo II, 3030-201 Coimbra (Portugal)

    2004-06-01

    In order to characterize the initial phase of the divergent detonation wave in PBX, a hemispheric explosive sample was initiated by a long cylindrical charge of the same explosive. The tested PBX is composed of 85 wt% of RDX and 15 wt% of binder based on HTPB. This PBX-RDX presents an effective density of 1.57 g/cm{sup 3}, and a detonation velocity of 7.90 mm/{mu}s. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  1. Detonation cell widths in hydrogen-air-diluent mixtures

    International Nuclear Information System (INIS)

    Stamps, D.W.

    1990-01-01

    In this paper I report on the influence of steam and carbon dioxide on the detonability of hydrogen-air mixtures. Data were obtained on the detonation cell width in a heated detonation tube that is 0.43 m in diameter and 13.1 m long. The detonation cell widths were correlated using a characteristic length calculated from a chemical kinetic model. The addition of either diluent to a hydrogen-air mixture increased the cell width for all equivalence ratios. For equal diluent concentrations, however, carbon dioxide not only yielded larger increases in the cell width than steam, but its efficacy relative to steam was predicted to increase with increasing concentration. The range of detonable hydrogen concentrations in a hydrogen-air mixture initially at 1 atm pressure was found to be between 11.6 percent and 74.9 percent for mixtures at 20 degree C and 9.4 percent and 76.9 percent for mixtures at 100 degree C. The detonation limit was between 38.8 percent and 40.5 percent steam for a stoichiometric hydrogen-air-steam mixture initially at 100 degree C and 1 atm. 10 refs., 4 figs., 1 tab

  2. 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.

  3. 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.

  4. les tumeurs benignes de la parotide benign parotid tumors

    African Journals Online (AJOL)

    Materials and Methods: We report a retrospective study of 48 cases of benign parotid tumors, collected over a period of 7 years. (2004-2010). ... superficial lobe tumor, a total parotidectomy was performed in 5 patients, an exofacialparotidectomy in 35 patients and a single tumor ..... Cancer Radiother 2005;9:251-60.

  5. On the deflagration-to-detonation transition (DDT) process with added energetic solid particles for pulse detonation engines (PDE)

    Science.gov (United States)

    Nguyen, V. B.; Li, J.; Chang, P.-H.; Phan, Q. T.; Teo, C. J.; Khoo, B. C.

    2018-01-01

    In this paper, numerical simulations are performed to study the dynamics of the deflagration-to-detonation transition (DDT) in pulse detonation engines (PDE) using energetic aluminum particles. The DDT process and detonation wave propagation toward the unburnt hydrogen/air mixture containing solid aluminum particles is numerically studied using the Eulerian-Lagrangian approach. A hybrid numerical methodology combined with appropriate sub-models is used to capture the gas dynamic characteristics, particle behavior, combustion characteristics, and two-way solid-particle-gas flow interactions. In our approach, the gas mixture is expressed in the Eulerian frame of reference, while the solid aluminum particles are tracked in the Lagrangian frame of reference. The implemented computer code is validated using published benchmark problems. The obtained results show that the aluminum particles not only shorten the DDT length but also reduce the DDT time. The improvement of DDT is primarily attributed to the heat released from surface chemical reactions on the aluminum particles. The temperatures associated with the DDT process are greater than the case of non-reacting particles added, with an accompanying rise in the pressure. For an appropriate range of particle volume fraction, particularly in this study, the higher volume fraction of the micro-aluminum particles added in the detonation chamber can lead to more heat energy released and more local instabilities in the combustion process (caused by the local high temperature), thereby resulting in a faster DDT process. In essence, the aluminum particles contribute to the DDT process of successfully transitioning to detonation waves for (failure) cases in which the fuel gas mixture can be either too lean or too rich. With a better understanding of the influence of added aluminum particles on the dynamics of the DDT and detonation process, we can apply it to modify the geometry of the detonation chamber (e.g., the length of

  6. NG2 cells are not a major source of reactive astrocytes after neocortical stab wound injury.

    Science.gov (United States)

    Komitova, Mila; Serwanski, David R; Lu, Q Richard; Nishiyama, Akiko

    2011-05-01

    NG2 cells are an abundant glial cell type in the adult brain. They are distinct from astrocytes, mature oligodendrocytes, and microglia. NG2 cells generate oligodendrocytes and a subpopulation of protoplasmic astrocytes in the ventral forebrain during development. To determine whether NG2 cells generate reactive astrocytes in the lesioned brain, stab wound injury was created in adult NG2creBAC:ZEG double transgenic mice, in which enhanced green fluorescent protein (EGFP) is expressed in NG2 cells and their progeny, and the phenotype of the EGFP(+) cells was analyzed at 10 and 30 days post lesion (dpl). The majority (>90%) of the reactive astrocytes surrounding the lesion that expressed glial fibrillary acidic protein (GFAP) lacked EGFP expression, and conversely the majority (>90%) of EGFP(+) cells were GFAP-negative. However, 8% of EGFP(+) cells co-expressed GFAP at 10 dpl. Most of these EGFP(+) GFAP(+) cells were morphologically distinct from hypertrophic reactive astrocytes and exhibited weak GFAP expression. NG2 was detected in a fraction of the EGFP(+) GFAP(+) cells found at 10 dpl. By 30 dpl the number of EGFP(+) GFAP(+) cells had decreased more than four-fold from 10 dpl. A similar transient appearance of EGFP(+) GFAP(+) cells with simple morphology was observed in NG2creER™:ZEG double transgenic mice in which EGFP expression had been induced in NG2 cells prior to injury. NG2 cell-specific deletion of the oligodendrocyte lineage transcription factor Olig2 using NG2creER™:Olig2(fl/fl) :ZEG triple transgenic mice did not increase the number of EGFP(+) reactive astrocytes. These findings suggest that NG2 cells are not a major source of reactive astrocytes in the neocortex. Copyright © 2011 Wiley-Liss, Inc.

  7. 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.

  8. Spectrum of benign breast diseases

    International Nuclear Information System (INIS)

    Khanzada, T.W.; Samad, A.; Sushel, C.

    2009-01-01

    Objective: To determine the frequencies of various benign breast diseases (BBD) in female patients in three private hospitals of Hyderabad. Methodology: This is a prospective cohort study of all female patients visiting the surgical clinic with breast problems. This study was conducted at Isra University Hospital Hyderabad and two other private hospitals of Hyderabad over a period of about three years starting from March 2004 to February 2007. All female patients visiting the surgical clinic with breast problems were included in the study. Patients with obvious clinical features of malignancy or those who on work up were diagnosed as carcinoma were excluded from the study. Results: A total of 275 patients were included in the study. About 44% (120/275) patients belonged to third decade of life (age between: 21-30 years) followed by 33% from forth decade (age between: 31- 40 years). Fibroadenoma was the most common benign breast disease, seen in 27% (75/275) of patients, followed by fibrocystic disease seen in about 21% (57/275) patients. Conclusion: Benign Breast Diseases (BBD) are common problems in females of reproductive age. Fibroadenoma is the commonest of all benign breast disease in our set up mostly seen in second and third decade of life. Fibrocystic disease of the breast is the next common BBD whose incidence increases with increasing age. (author)

  9. Benign breast lesions in Kano

    African Journals Online (AJOL)

    malignant breast diseases. But the prevalence of breast cancer is increasing especially in communities that hitherto reported low incidence; a recent report from Ibadan cancer registry, showed that ... Table Relative frequency of breast lesions in Kano. Histological No. % of breast % of benign breast diagnosis lesions lesions.

  10. Benign paroxysmal positional vertigo treatment

    DEFF Research Database (Denmark)

    West, Niels; Hansen, Søren; Bloch, Sune Land

    2017-01-01

    Benign paroxysmal positional vertigo (BPPV) remains the most frequent cause of vertigo. The TRV chair is a mechanical device suited for optimization of managing complex cases of BPPV. Although the use of repositioning devices in the management of BPPV is increasing, no applicable guide for the TRV...

  11. Scintigraphy in benign bone tumours

    African Journals Online (AJOL)

    1989-08-05

    Aug 5, 1989 ... benign osteoblastoma. Case 3. An 18-year-old boy presented to hospital with progressively worsening pain in the right buttock, which he related to a fall the previous year. Physical examination elicited an area of tenderness over the sacrum with an area of paraesthesia over the right buttock. Radiography ...

  12. 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.

  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. Detonation-to-shock wave transmission at a contact discontinuity

    Science.gov (United States)

    Peace, J. T.; Lu, F. K.

    2018-02-01

    The one-dimensional interaction of a detonation wave with a contact discontinuity was investigated analytically and experimentally for oxyhydrogen detonations. The analytical and experimental results showed that the transmitted shock through the contact surface and into a non-combustible gas can either be amplified or attenuated depending on the reflection type at the contact surface and on the ratio of acoustic impedance across it. Experiments were performed with a detonation-driven shock tube facility to determine the transmitted shock velocity into a non-combustible He/air mixture. The oxyhydrogen equivalence ratio in the detonation section was varied from 0.5 to 1.5, and the driven section He mole fraction was varied from 0.0 to 1.0 to test a broad range of acoustic impedance ratios ranging from approximately 0.36 to 1.69. The analytical results were shown to have acceptable agreement with the measured transmitted shock wave velocity in the case of a reflected rarefaction from the contact surface. Additionally, the results indicated that the detonation wave reaction zone properties could have an important role that influences the transmitted shock properties in the case of a reflected shock from the contact surface.

  15. Numerical Simulations of Detonation Instabilities and Magnetic Field Interactions

    Science.gov (United States)

    Cole, Lord; Le, Hai; Karagozian, Ann

    2011-11-01

    Numerical simulations of magneto-hydrodynamic (MHD) effects on high frequency and low frequency one-dimensional detonation wave instabilities are performed, with applications to flow control and MHD thrust augmentation in Pulse Detonation Engines and their design variations. The dynamics of the hydrogen-air detonation are explored via high order shock capturing schemes and complex reaction kinetics. The flame is initially strongly coupled to the shock and the wave is over-driven. As the degree of overdrive decays and the detonation approaches the CJ limit, high frequency instabilities begin to appear. Eventually the average induction length continues to increase and a second mode can be seen which directly couples the flame speed with the shock, resulting in fluctuations with lower frequency but much higher amplitude. A simple model for flame-shock coupling replicates the quantitative features of these instabilities quite well. Effects of an externally applied magnetic field on these detonation instabilities are explored. In addition, the complex chemical kinetics calculations are ported onto a GPU, and computational performance may be compared with standard CPU-based computations. Supported by AFOSR and AFRL/RZSS.

  16. 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

  17. Detonation Synthesis of Alpha-Variant Silicon Carbide

    Science.gov (United States)

    Langenderfer, Martin; Johnson, Catherine; Fahrenholtz, William; Mochalin, Vadym

    2017-06-01

    A recent research study has been undertaken to develop facilities for conducting detonation synthesis of nanomaterials. This process involves a familiar technique that has been utilized for the industrial synthesis of nanodiamonds. Developments through this study have allowed for experimentation with the concept of modifying explosive compositions to induce synthesis of new nanomaterials. Initial experimentation has been conducted with the end goal being synthesis of alpha variant silicon carbide (α-SiC) in the nano-scale. The α-SiC that can be produced through detonation synthesis methods is critical to the ceramics industry because of a number of unique properties of the material. Conventional synthesis of α-SiC results in formation of crystals greater than 100 nm in diameter, outside nano-scale. It has been theorized that the high temperature and pressure of an explosive detonation can be used for the formation of α-SiC in the sub 100 nm range. This paper will discuss in detail the process development for detonation nanomaterial synthesis facilities, optimization of explosive charge parameters to maximize nanomaterial yield, and introduction of silicon to the detonation reaction environment to achieve first synthesis of nano-sized alpha variant silicon carbide.

  18. Characterization of Pulse Detonation Engine Performance with Varying Free Stream Stagnation Pressure Levels

    National Research Council Canada - National Science Library

    Knick, Wesley R

    2006-01-01

    A pulse detonation engine operates on the principle that a fuel-air mixture injected into a tube will ignite and undergo a transition from a deflagration to a detonation and exit the tube at supersonic velocities...

  19. Thermally Bonded PET–Basalt Sandwich Composites for Heat Pipeline Protection: Preparation, Stab Resisting, and Thermal-Insulating Properties

    Directory of Open Access Journals (Sweden)

    Ting-Ting Li

    2018-03-01

    Full Text Available In order to solve the cost and bulky problems of buried thermal pipeline insulating materials, this study adopts basalt fabric and low-melting PET nonwoven to construct low-cost and light-weight pipeline thermal-insulating composites after needle punching and thermal bonding processes. Research result shows that thermal-bonded temperature affected the stab resistance and burst energy more significantly. As thermal-bonded temperature increased, knife resistance and spike resistance presented the upward and then downward trends, but the burst energy gradually decreased. Yarn pull-out result shows that the enhancement of stab resistance of intra-/inter-thermal-bonded structure resulted from the increment in the coefficient of friction between yarns. When PET–basalt sandwich composites were thermal-bonded at 140 °C for 5 min, the maximum knife and spike resistance were 147.00 N (1.99 J and 196.30 N (1.11 J, respectively, and burst energy was 4.79 J, thermal conductivity reduced to 0.0073 W/(m∙K. The resultant thermally bonded sandwich composites can be used as thermal-insulating protection for buried thermal pipeline.

  20. Penetrating Stab Injuries to the Anterior Abdomen: Use of Multi-Detector Computed Tomography to Predict the Need for Laparotomy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dae Hong; Choi, Seung Joon; Jeong, Yu Mi; Kim, Hyung Sik; Choi, Hye Young [Dept. of Radiology, Gachon University, Gil Hospital, Incheon (Korea, Republic of)

    2013-01-15

    The aim of this study was to determine how well multi-detector computed tomography (MDCT) scans predict the need for a laparotomy in patients with anterior abdominal stab injuries. Eighty patients with abdominal stab injuries who underwent MDCT scans were enrolled. MDCT was performed to identify active bleeding and injured organs and to assess the accuracy between MDCT and the laparotomy findings. MDCT was considered positive or negative with respect to the need for an exploratory laparotomy. The diagnostic performance of MDCT for identifying the need for laparotomy was estimated. MDCT predicted bowel and mesentery injuries in 31 of 80 patients and 28 patients were truly positive. MDCT predicted active bleeding in 23 of 80 patients and 19 patients had active bleeding. MDCT predicted the need for laparotomy in 43 of 80 patients. A laparotomy was performed in 55 of the 80 patients and 42 were therapeutic. Overall, a MDCT scan predicted the need for laparotomy with 95% sensitivity, 92% specificity, and 93% accuracy. MDCT scans can be used to identify active bleeding and injured organs and are an effective tool for determining the need for surgical exploration.

  1. 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. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Imaging of Benign Odontogenic Lesions.

    Science.gov (United States)

    Scarfe, William C; Toghyani, Shiva; Azevedo, Bruno

    2018-01-01

    Numerous benign cysts or solid tumors may present in the jaws. These arise from tooth-forming tissues in the dental alveolus or from nonodontogenic tissues in the basal bone of the mandible and maxilla. Radiologists provide 2 deliverables to assist in diagnosis and management: (1) appropriately formatted images demonstrating the location and extent of the lesion and (2) interpretive reports highlighting specific radiologic findings and an impression providing a radiologic differential diagnosis. This article provides guidance on essential image protocols for planning treatments, a radiologic differential diagnostic algorithm based on location and pattern recognition, and a summary of the main features of benign odontogenic lesions. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Pulse Detonation Engine Air Induction System Analysis

    Science.gov (United States)

    Pegg, R. J.; Hunter, L. G.; Couch, B. D.

    1996-01-01

    A preliminary mixed-compression inlet design concept for potential pulse-detonation engine (PDE) powered supersonic aircraft was defined and analyzed. The objectives of this research were to conceptually design and integrate an inlet/PDE propulsion system into a supersonic aircraft, perform time-dependent CFD analysis of the inlet flowfield, and to estimate the installed PDE cycle performance. The study was baselined to a NASA Mach 5 Waverider study vehicle in which the baseline over/under turboramjet engines were replaced with a single flowpath PDE propulsion system. As much commonality as possible was maintained with the baseline configuration, including the engine location and forebody lines. Modifications were made to the inlet system's external ramp angles and a rotating cowl lip was incorporated to improve off-design inlet operability and performance. Engines were sized to match the baseline vehicle study's ascent trajectory thrust requirement at Mach 1.2. The majority of this study was focused on a flight Mach number of 3.0. The time-dependent Navier Stokes CFD analyses of a two-dimensional approximation of the inlet was conducted for the Mach 3.0 condition. The Lockheed Martin Tactical Aircraft Systems-developed FALCON CFD code with a two equation 'k-1' turbulence model was used. The downstream PDE was simulated by an array of four sonic nozzles in which the flow areas were rapidly varied in various opening/closing combinations. Results of the CFD study indicated that the inlet design concept operated successfully at the Mach 3.0 condition, satisfying mass capture, total pressure recovery, and operability requirements. Time-dependent analysis indicated that pressure and expansion waves from the simulated valve perturbations did not effect the inlet's operability or performance.

  4. 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.

  5. Blue breath holding is benign.

    OpenAIRE

    Stephenson, J B

    1991-01-01

    In their recent publication in this journal, Southall et al described typical cyanotic breath holding spells, both in otherwise healthy children and in those with brainstem lesions and other malformations. Their suggestions regarding possible autonomic disturbances may require further study, but they have adduced no scientific evidence to contradict the accepted view that in the intact child blue breath holding spells are benign. Those families in which an infant suffers an 'apparently life t...

  6. Effect of microstructure on the detonation initiation in energetic materials

    Science.gov (United States)

    Zhang, J.; Jackson, T. L.

    2017-12-01

    In this work we examine the role of the microstructure on detonation initiation of energetic materials. We solve the reactive Euler equations, with the energy equation augmented by a power deposition term. The deposition term is based on simulations of void collapse at the microscale, modeled at the mesoscale as hot-spots, while the reaction rate at the mesoscale is modeled using density-based kinetics. We carry out two-dimensional simulations of random packs of HMX crystals in a binder. We show that mean particle size, size distribution, and particle shape have a major effect on the transition between detonation and no-detonation, thus highlighting the importance of the microstructure for shock-induced initiation.

  7. Simulating sympathetic detonation using the hydrodynamic models and constitutive equations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Hoon; Kim, Min Sung; Yoh, Jack J. [Dept. of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Sun, Tae Boo [Hanwha Corporation Defense Rand D Center, Daejeon (Korea, Republic of)

    2016-12-15

    A Sympathetic detonation (SD) is a detonation of an explosive charge by a nearby explosion. Most of times it is unintended while the impact of blast fragments or strong shock waves from the initiating donor explosive is the cause of SD. We investigate the SD of a cylindrical explosive charge (64 % RDX, 20 % Al, 16 % HTPB) contained in a steel casing. The constitutive relations for high explosive are obtained from a thermo-chemical code that provides the size effect data without the rate stick data typically used for building the rate law and equation of state. A full size SD test of eight pallet-packaged artillery shells is performed that provides the pressure data while the hydrodynamic model with proper constitutive relations for reactive materials and the fragmentation model for steel casing is conducted to replicate the experimental findings. The work presents a novel effort to accurately model and reproduce the sympathetic detonation event with a reduced experimental effort.

  8. Simulating sympathetic detonation using the hydrodynamic models and constitutive equations

    International Nuclear Information System (INIS)

    Kim, Bo Hoon; Kim, Min Sung; Yoh, Jack J.; Sun, Tae Boo

    2016-01-01

    A Sympathetic detonation (SD) is a detonation of an explosive charge by a nearby explosion. Most of times it is unintended while the impact of blast fragments or strong shock waves from the initiating donor explosive is the cause of SD. We investigate the SD of a cylindrical explosive charge (64 % RDX, 20 % Al, 16 % HTPB) contained in a steel casing. The constitutive relations for high explosive are obtained from a thermo-chemical code that provides the size effect data without the rate stick data typically used for building the rate law and equation of state. A full size SD test of eight pallet-packaged artillery shells is performed that provides the pressure data while the hydrodynamic model with proper constitutive relations for reactive materials and the fragmentation model for steel casing is conducted to replicate the experimental findings. The work presents a novel effort to accurately model and reproduce the sympathetic detonation event with a reduced experimental effort

  9. Synthesis of carbon-coated iron nanoparticles by detonation technique

    International Nuclear Information System (INIS)

    Sun, Guilei; Li, Xiaojie; Wang, Qiquan; Yan, Honghao

    2010-01-01

    Carbon-coated iron nanoparticles were synthesized by detonating a mixture of ferrocene, naphthalene and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in an explosion vessel under low vacuum conditions (8.1 kPa). The RDX functioned as an energy source for the decomposition of ferrocene and naphthalene. The carbon-coated iron nanoparticles were formed as soot-like deposits on the inner surface of the reactor, which were characterized by XRD, TEM, HRTEM, Raman spectroscopy and vibrating sample magnetometer. And a portion of the detonation soot was treated with hydrochloric acid. The product was carbon-coated nanoparticles in perfect core-shell structures with graphitic shells and bcc-Fe cores. The detonation technique offers an energy-saving route to the synthesis of carbon-coated nanomaterials.

  10. 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.

  11. Controlled Detonation Dynamics in Additively Manufactured High Explosives

    Science.gov (United States)

    Schmalzer, Andrew; Tappan, Bryce; Bowden, Patrick; Manner, Virginia; Clements, Brad; Menikoff, Ralph; Ionita, Axinte; Branch, Brittany; Dattelbaum, Dana; Espy, Michelle; Patterson, Brian; Wu, Ruilian; Mueller, Alexander

    2017-06-01

    The effect of structure in explosives has long been a subject of interest to explosives engineers and scientists. Through structure, detonation dynamics in explosives can be manipulated, introducing a new level of safety and directed performance into these previously difficult to control materials. New advances in additive manufacturing (AM) allow the deliberate introduction of exact internal structures at dimensions approaching the mesoscale of these energetic materials. We show through simulation and experiment that this structure can be used to control detonation behavior by manipulating complex shockwave interactions. We use high-speed video and shorting mag-wires to determine the detonation velocity in AM generated explosive structures, demonstrating, for the first time, a method of controlling the directional propagation of reactive flow through the controlled introduction of structure within a high explosive. With ongoing improvement in the AM methods available coupled with guidance through modeling and simulations, more complex interactions are being explored. LANL LDRD Office.

  12. Study on low velocity detonation phenomena in Nitromethane

    Directory of Open Access Journals (Sweden)

    A Osada

    2016-04-01

    Full Text Available In detonation of an explosive, there are two forms, high velocity detonation(HVD and low velocity detonation (LVD. For example, it is known that thedetonation velocities of methyl nitrate are 6700m/s in HVD and 2500m/s inLVD. In a liquid explosive, the highest pressure of LVD changes with thetype of explosive and conditions, is a few GPa and has destructive powerequivalent to HVD. It is important also for security to get to know the actualcondition of LVD. Moreover, it is important that the performance ofexplosives is completely understood to control HVD, LVD, and deflagration,and to predict the behavior of the explosive.

  13. The Correlation of Electrical Fields and Detonator Behavior

    Science.gov (United States)

    Wilde, Zakary; Francois, Elizabeth; Gibson, John; Lodes, Rylie; Nakamoto, Teagan; Parrack, Kristina; Smith, Dalton; Tasker, Douglas; Trujillo, Christopher

    2017-06-01

    It is well established that behavior of the shock is affected by the microstructure of the explosive. Diagnostics are being developed to utilize Polyvinylidene fluoride (PVDF) gauges for shock wave detection and observing transient electric fields generated by shocked Pentaerythritol Tetranitrate (PETN), which is a piezoelectric explosive. This study has the goal of determining whether PVDF gauges can detect the electrical signature generated by the shock compression of PETN crystals and correlate it with the explosive material microstructure and shock to detonation transition (SDT) process in slapper detonators. Slapper detonators function by inputting current to an exploding foil initiator. The metal foil converts to a plasma causing a thin polymer layer to separate at high velocity and impact the explosive resulting in the SDT. Experiments will observe correlations between changes in the electrical signals and explosive microstructure. LA-UR-17-20883.

  14. Thermal stability of detonation-produced micro and nanodiamonds

    Science.gov (United States)

    Efremov, V. P.; Zakatilova, E. I.; Maklashova, I. V.; Shevchenko, N. V.

    2018-01-01

    Detonation nanodiamonds are produced at utilization of high explosives. When an explosive blasts in a water environment, the detonation products contain microdiamonds, and in a gaseous medium, nanodiamonds. It is known that with decreasing size the influence of the surface energy of particles on their properties increases. Thus, it is interesting to compare the properties of detonation nano and microdiamonds. In this study, we have examined the thermal stability of diamond materials by synchronous thermal analysis. The experiments were performed at atmospheric pressure in argon flow for different heating rates in a range from room temperature to 1500 °C. Samples of initial and annealed micro and nanomaterials were studied using electron microscopy, x-ray and x-ray-fluorescence analysis. It was established that thermal and structural properties of micro and nanodiamonds differ substantially.

  15. On Possibility of Detonation Products Temperature Measurements of Emulsion Explosives

    Directory of Open Access Journals (Sweden)

    Silvestrov V. V.

    2014-10-01

    Full Text Available The new view on the structure of the radiance signal recorded by optical pyrometer and the preliminary results of brightness detonation temperature of the emulsion explosive are presented. The structure of an optical signal observed is typical for the heterogeneous explosives. First, there is the short temperature spike to 2500 ÷ 3300 K connecting with a formation of “hot spots” assembly that fire the matrix capable of exothermal reaction. Then the relaxation of radiance to equilibrium level is observed that corresponds to brightness temperature 1840 ÷ 2260 K of explosion products at detonation pressure 1 ÷ 11 GPa. Experimental results are compared with the calculations of other authors. The detonation temperature of the investigated explosive is measured for the first time.

  16. Detonation Energies of Explosives by Optimized JCZ3 Procedures

    Science.gov (United States)

    Stiel, Leonard; Baker, Ernest

    1997-07-01

    Procedures for the detonation properties of explosives have been extended for the calculation of detonation energies at adiabatic expansion conditions. Advanced variable metric optimization routines developed by ARDEC are utilized to establish chemical reaction equilibrium by the minimization of the Helmholtz free energy of the system. The use of the JCZ3 equation of state with optimized Exp-6 potential parameters leads to lower errors in JWL detonation energies than the TIGER JCZ3 procedure and other methods tested for relative volumes to 7.0. For the principal isentrope with C-J parameters and freeze conditions established at elevated pressures with the JCZ3 equation of state, best results are obtained if an alternate volumetric relationship is utilized at the highest expansions. Efficient subroutines (designated JAGUAR) have been developed which incorporate the ability to automatically generate JWL and JWLB equation of state parameters. abstract.

  17. 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.

  18. The analysis of thermal stability of detonation nanodiamond

    International Nuclear Information System (INIS)

    Efremov, V P; Zakatilova, E I

    2016-01-01

    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. (paper)

  19. Detonation propagation in annular arcs of condensed phase explosives

    Science.gov (United States)

    Ioannou, Eleftherios; Schoch, Stefan; Nikiforakis, Nikolaos; Michael, Louisa

    2017-11-01

    We present a numerical study of detonation propagation in unconfined explosive charges shaped as an annular arc (rib). Steady detonation in a straight charge propagates at constant speed, but when it enters an annular section, it goes through a transition phase and eventually reaches a new steady state of constant angular velocity. This study examines the speed of the detonation wave along the annular charge during the transition phase and at steady state, as well as its dependence on the dimensions of the annulus. The system is modeled using a recently proposed diffuse-interface formulation which allows for the representation of a two-phase explosive and of an additional inert material. The explosive considered is the polymer-bonded TATB-based LX-17 and is modeled using two Jones-Wilkins-Lee (JWL) equations of state and the ignition and growth reaction rate law. Results show that steady state speeds are in good agreement with experiment. In the transition phase, the evolution of outer detonation speed deviates from the exponential bounded growth function suggested by previous studies. We propose a new description of the transition phase which consists of two regimes. The first regime is caused by local effects at the outer edge of the annulus and leads to a dependence of the outer detonation speed on the angular position along the arc. The second regime is induced by effects originating from the inner edge of the annular charge and leads to the deceleration of the outer detonation until steady state is reached. The study concludes with a parametric study where the dependence of the steady state and the transition phase on the dimensions of the annulus is investigated.

  20. 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

  1. 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.

  2. Non-classical detonation regimes of liquid high explosives

    Science.gov (United States)

    Utkin, A. V.; Mochalova, V. M.

    2018-01-01

    This paper presents experimental data of studies of the liquid explosives characteristics, in the reaction zone of which the distribution of parameters does not correspond to the classical detonation theory. An increase of the pressure and particle velocity behind a shock jump in liquid explosives and the possibility of the existence of a steady-state detonation wave without a von Neumann spike are interpreted within the framework of models that take into account the possibility of chemical reactions directly in the shock wave front.

  3. Numerical modeling of the deflagration-to-detonation transition

    International Nuclear Information System (INIS)

    Forest, C.A.

    1978-01-01

    The effect of a confined porous bed of burning explosive in contact with a solid explosive is studied by computer simulation. The burning is modeled using a bulk burn model that is a function of the surface area and the pressure. Once pressure excursions occur from the confined burning the transition to detonation is modeled using a pressure-dependent heterogeneous explosive shock decomposition model called Forest Fire. The occurrence of detonation in the solid explosive is shown to be dependent upon the surface-to-volume ratio, the confinement of the porous bed, and the geometry of the system

  4. Initiation of detonation by impact on granular explosives

    International Nuclear Information System (INIS)

    Bernier, H.

    1964-05-01

    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) [fr

  5. Using an electronic detonator system and expanded blast patterns to prevent sympathetic detonation at Powder River Basin coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R.; Fleetwood, K.; Haid, J. [Orica USA Inc., Watkins, CO (United States). Advanced Mining Solutions

    2005-07-01

    This paper describes a systematic approach to prevent cast blast holes from detonating sympathetically through the use of the electronic initiation and expanded blast patterns. In-situ measurements were recorded from pressure probes, velocity of detonation probes and near field accelerometers, along with digital images generated from a high speed CCD camera. Large diameter angled drill holes were also checked for any measurable amount of deviation by a cable type borehole measurement tool. The field measurements provided the scientific evidence, statistical data, and documentation necessary to develop a sound method or a 'road map' that would minimize and in some situations prevent the occurrence of blast hole sympathetic detonation. 2 refs., 3 figs.

  6. Blue breath holding is benign.

    Science.gov (United States)

    Stephenson, J B

    1991-01-01

    In their recent publication in this journal, Southall et al described typical cyanotic breath holding spells, both in otherwise healthy children and in those with brainstem lesions and other malformations. Their suggestions regarding possible autonomic disturbances may require further study, but they have adduced no scientific evidence to contradict the accepted view that in the intact child blue breath holding spells are benign. Those families in which an infant suffers an 'apparently life threatening event' deserve immense understanding and help, and it behoves investigators to exercise extreme care and self criticism in the presentation of new knowledge which may bear upon their management and their morale. PMID:2001115

  7. Deflagration-to-detonation transition in granular HMX

    Science.gov (United States)

    Campbell, A. W.

    1980-01-01

    Granular HMX of three degrees of fineness was packed into heavy-walled steel tubes closed at both ends. Ignition was obtained at one end using an intimate mixture of finely divided titanium and boron as an igniter that produced heat with little gas. The distance to detonation was determined by examination of the resulting tube fragments. By inserting tightly-fitted neoprene diaphragms periodically into the HMX column, it was shown that the role of convective combustion was limited to the initial stage of the deflagration to detonation (DDT) process. Experiments in which various combinations of two of the three types of HMX were loaded into the same tube showed that heating by adiabatic shear of explosive grains was an essential factor in the final buildup to detonation. A description of the DDT process is developed in which conductive burning is followed in turn by convective burning, bed collapse with plug formation, onset of accelerated burning at the front of the plug through heating by intercrystalline friction and adiabatic shear, and intense shock formation resulting in high-order detonation.

  8. Thermal Behaviour and Detonation Characterization of N-Benzoyl-3 ...

    African Journals Online (AJOL)

    The apparent activation energy, pre-exponential factor and the mechanism function are 170.77 kJ mol–1, 1014.12 s–1 and f(α) = (1–a)–1/2, respectively. The specific ... The detonation velocity (D) and pressure (P) of BDNAZ were estimated by using the nitrogen equivalent equation according to the experimental density.

  9. 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.

  10. 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.

  11. 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

  12. Numeričko modeliranje detonacije / Numerical modelling of detonation

    Directory of Open Access Journals (Sweden)

    Radun Jeremić

    2002-03-01

    Full Text Available Radi izračunavanja teorijskih vrednosti detonacionih parametara različitih eksplozivnih sastava izvršeno je numeričko modeliranje detonacije i sačinjen računarski program u programskom paketu PASCAL. Za opisivanje ponašanja produkata detonacije primenjena je BK.W jednačina stanja, a sistem jednačina hemijske ravnoteže rešavan je metodom minimizacije slobodne energije. Testiranje programskog rešenja izvršeno je za nekoliko eksplozivnih sastava različitih gustina, pri čemu je ostvarena dobra konvergencija rešenja i velika brzina rada. Dobijeno je dobro slaganje eksperimentalnih i teorijskih vrednosti pritisaka i brzina detonacije, čime je potvrđena ispravnost modela. / Numerical modeling of detonation of different explosive compositions has been carried out in order to calculate theoretical values of detonation parameters. A computer program in the PASCAL program package has been created. The BKW state equation has been applied to describe the behavior of detonation products and the equation system of chemical equilibrium has been solved by the method of free energy minimization. The program has been tested for several explosive compositions of various densities, operation speed being high and solution convergence good. The experimental and theoretical values of pressures and detonation velocities show good accordance, which confirms the model validity.

  13. Exhaust Gas Emissions from a Rotating Detonation-wave Engine

    Science.gov (United States)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2015-11-01

    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. The performance of a baseline hydrogen/air RDE increased from 4940 s to 5000 s with the expansion flow chemistry, due to recombination of radicals and more production of H2O, resulting in additional heat release. Work sponsored by the Office of Naval Research.

  14. 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.

  15. 29 CFR 1926.908 - Use of detonating cord.

    Science.gov (United States)

    2010-07-01

    ... connectors or short-interval-delay electric blasting caps are used with detonating cord, the practice shall conform strictly to the manufacturer's recommendations. (i) When connecting a blasting cap or an electric... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.908 Use...

  16. Initiation of unconfined gas detonations in hydrocarbon-air mixtures by a sympathetic mechanism

    International Nuclear Information System (INIS)

    Bull, D.C.; Elsworth, J.E.

    1981-01-01

    The considered investigation is concerned with the study of the factors which influence detonation propagation in a gas of heterogeneous composition. The conducted experiments assess the ability of a blast wave, emerging from a donor gas detonation and crossing an air gap, to initiate detonation in a second, similar, acceptor gas mixture. Stoichiometric mixtures of both ethylene-air and propane-air are found to exhibit 'sympathetic' gas detonation only across small air gaps. Conditions critical to sympathetic gas detonation agree with predictions of a simple theory taking account of the net shock decay occurring across two acoustic interfaces bounded by an air gap. Sympathetic detonation occurs only if the strength of the shock upon entering the acceptor exceeds a threshold value for the particular gas mixture. Reinitiation of detonation is not satisfactorily explained by planar blast wave decay and autoignition considerations

  17. Haemocompatibility Of Non-Functionalized And Plasmachemical Functionalized Detonation Nanodiamond Particles

    Directory of Open Access Journals (Sweden)

    Mitura K.

    2015-09-01

    Full Text Available The purpose of this paper is to present the innovative design of microwave plasma system for modification of detonation nanodiamond particles (DNP using a special rotating drum placed inside the reactor. Nanodiamond particles manufactured by detonation method reveal the biological activity depending on surface functionalization. Plasmachemical modification of detonation nanodiamond particles gives the possibility of controlling surface of nanodiamonds particles in biological tests. In this paper we would like to compare detonation nanodiamond (the grain sizes from 2 to 5 nm with modified detonation nanodiamond in rotary reactor chamber, by microwave plasma activated chemical vapour deposition (MW PACVD method in materials research (Raman and FT-IR spectroscopy and in vitro examinations with full of human blood. The results indicate haemocompatibility of non-modified detonation nanodiamond and modified nanodiamond by MW PACVD method in rotary reactor chamber (modified ND-3 and the presence of haemolysis in commercial detonation nanodiamond.

  18. [Benign partial epilepsies of childhood].

    Science.gov (United States)

    Palencia, R

    To carry out, by means of a literature review, an update of the entities that can be included within the group of benign partial epilepsies of childhood. Among partial epilepsies with onset in the first stages of life, a group extended in the last years with a favourable course and a trend to reverse, even spontaneously, has been identified. Some of these entities have a genetic origin but we do not know the mechanisms by which these epilepsies show a self limited course, which have given rise to the denomination of epilepsy that comes and goes; nevertheless, an evolution to other more complex forms is also possible. Benign partial epilepsies of childhood constitute a wide group of conditions of varied semiology, usually with a good prognosis even without treatment. Occasionally, these epilepsies may show a more unfavourable course with a worsening, in spite of medication, and the appearance of neurologic and neuropsychologic disorders. All these aspects must be known and considered by the physician in charge of these patients management.

  19. Retroperitoneoscopic nephrectomy in benign pathology.

    Science.gov (United States)

    Quintela, Rodrigo S; Cotta, Leonardo R; Neves, Marcelo F; Abelha, David L; Tavora, Jose E

    2006-01-01

    We report our experience with 43 retroperitoneal laparoscopic nephrectomy for benign kidney disease. All patients had a poor function from obstructive uropathology and renal atrophy. None of these patients had a previous lumbotomy. Retroperitoneoscopy was performed with 4 trocar port technique in a lateral position. The retroperitoneal space is created by using a Gaur's balloon made of sterile glove. The approach to vascular pedicle was done posteriorly and vessels were clipped by metal and Hem-o-lock (Weck Closure Systems, North Carolina, USA) clips. The sample was intact extracted in an Endo-Bag prolonging one trocar incision. Median operative time was 160 minutes and median blood loss was 200 mL. Four cases (9%) were converted to open surgery: one case due to bleeding and 3 cases due to technical difficulties regarding perirenal adherences. Most patients (39) checked out from the Hospital in day two. Four of them were left over 3 days due to wound complications. Retroperitoneoscopy offers a safe, effective and reproductive access to nephrectomy for benign pathologies.

  20. Diagnostic Accuracy of Abdominal wall Ultrasonography and Local Wound Exploration in Predicting the Need for Laparotomy following Stab Wound

    Directory of Open Access Journals (Sweden)

    Ali Vafaei

    2017-01-01

    Full Text Available Introduction: Screening of patients with anterior abdominal penetrating trauma in need for laparotomy is an important issue in management of these cases. This study aimed to compare the accuracy of abdominal wall ultrasonography (AWU and local wound exploration (LWE in this regard.Methods: This diagnostic accuracy study was conducted on ≥ 18 year-old patients presenting to emergency department with anterior abdominal stab wound and stable hemodynamics, to compare the characteristics of AWU and LWE in screening of patients in need of laparotomy.Results: 50 cases with the mean age of 28.44 ± 7.14 years were included (80% male. Sensitivity, specificity and area under the receiver operating characteristic (ROC curve of AWU were 70.58 (95% CI: 44.04 – 88.62, 93.33 (95% CI: 76.49 – 98.83, and 81.96 (95% CI: 69.91 – 94.01, respectively. These measures were 88.23 (62.25 – 97.93, 93.33 (76.49 – 98.83, and 90.78 (95% CI: 81.67 – 99.89 for LWE, respectively. The difference in overall accuracy of the two methods was not statistically significant (p = 0.0641.Conclusion: Based on the findings of the present study, AWU and LWE had the same specificity but different sensitivities in screening of anterior abdominal stab wound patients in need of laparotomy. The overall accuracy of LWE was slightly higher (91.48% versus 85.1%.

  1. Hemihypertrophy, renal dysplasia and benign nephromegaly.

    Science.gov (United States)

    Memon, Mohammad Amin; Mohanty, Suravi; Das, Kanishka; Garg, Isha; D'Cruz, Ashley Lucien Joseph

    2005-06-01

    Hemihypertrophy is associated with malignant visceral abdominal neoplasms in childhood. Benign nephromegaly and nephroblastomas are both known to occur with hemihypertrophy; however, association with renal dysplasia has not previously reported. We describe an infant presenting with recurrent haematuria who had segmental hemihypertrophy, ipsilateral renal dysplasia and contralateral benign nephromegaly. Although debated, renal dysplasia may predispose to and predate malignant change. Rational management and optimal surveillance of renal dysplasia and benign nephromegaly in hemihypertrophy is discussed.

  2. 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

    tracking of the luminous fireball growth. Elapsed time is recorded by taking the difference of the embedded time stamps between successive frames. After...Boyce, and J-P Coudoing, "Nanometric aluminium powder influence on the detonation efficiency of explosives," in Int. Det. Symp., 2002. 42. Lewis

  3. A Reaction Zone Enthalpy Balance Model to Simulate Shock-to-Detonation Transition and Unsteady Detonation Wave Propagation

    Science.gov (United States)

    Froger, A.

    2004-07-01

    The standard models in use to simulate the reactive detonation wave propagation are not accurate in computing the transient evolutions because they focus on the shock front, not on the reaction zone where the coupling of thermodynamic and mechanic effects occurs. The model we propose is based on a new thermodynamic description of the constituents in the reaction zone, and on the use of the enthalpy balance of the chemical reaction as the energetic parameter instead of the heat of reaction. The enthalpy balance of the reaction results from the enthalpies of formation of all the chemical species involved in the reaction and is, therefore, a physical constant. The model is based on four basic assumptions: -1) the reaction zone is anevolving intimate mixture of non-reacted material and detonation products, -2) the energy released by thereaction is inherent to the detonation products alone, -3) the two constituents have the same pressure but different temperatures, -4) the specific energy released is not a constant but is related to the enthalpy balance and depends on the thermodynamic state. The model only needs the physical properties of the materials (equations of state of the constituents, chemical reaction and initiation delay), not the CJ state nor any other sub-model. When coupled with the Euler equations this thermodynamic description of the reaction zone permits us to simulate the transient evolution of an emerging detonation for any geometry (2D or 3D) or confinement structure.

  4. Familial benign nonprogressive myoclonic epilepsies.

    Science.gov (United States)

    Striano, Pasquale; de Falco, Fabrizio A; Minetti, Carlo; Zara, Federico

    2009-05-01

    Work on the classification of epileptic syndromes is ongoing, and many syndromes are still under discussion. In particular, special difficulty still persists in correctly classifying epilepsies with myoclonic seizures. The existence of special familial epileptic syndromes primarily showing myoclonic features has been recently suggested on the basis of a clear pattern of inheritance or on the identification of new chromosomal genetic loci linked to the disease. These forms in development include familial infantile myoclonic epilepsy (FIME), benign adult familial myoclonic epilepsy (BAFME), or autosomal dominant cortical myoclonus and epilepsy (ADCME), and, maybe, adult-onset myoclonic epilepsy (AME). In the future, the identification of responsible genes and the protein products will contribute to our understanding of the molecular pathways of epileptogenesis and provide neurobiologic criteria for the classification of epilepsies, beyond the different phenotypic expression.

  5. 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...... because of environmental constraints are particularly suited for solution with the hybrid method. Application of the hybrid method is highlighted through two illustrative examples. The first example involves the determination of an optimal flowsheet for the removal of a chemical species from an azeotropic...

  6. 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.

  7. Mechanism of Gaseous Detonation Propagation Through Reactant Layers Bounded by Inert Gas

    Science.gov (United States)

    Houim, Ryan

    2017-11-01

    Vapor cloud explosions and rotating detonation engines involve the propagation of gaseous detonations through a layer of reactants that is bounded by inert gas. Mechanistic understanding of how detonations propagate stably or fail in these scenarios is incomplete. Numerical simulations were used to investigate mechanisms of gaseous detonation propagation through reactant layers bounded by inert gas. The reactant layer was a stoichiometric mixture of C2H4/O2 at 1 atm and 300K and is 4 detonation cells in height. Cases where the inert gas temperature was 300, 1500, and 3500 K will be discussed. The detonation failed for the 300 K case and propagated marginally for the 1500 K case. Surprisingly, the detonation propagated stably for the 3500 K case. A shock structure forms that involves a detached shock in the inert gas and a series of oblique shocks in the reactants. A small local explosion is triggered when the Mach stem of a detonation cell interacts with the compressed reactants behind one of these oblique shocks. The resulting pressure wave produces a new Mach stem and a new triple point that leads to a stable detonation. Preliminary results on the influence of a deflagration at the inert/reactant interface on the stability of a layered detonation will be discussed.

  8. Double jeopardy revisited: clinical decision making in unstable patients with, thoraco-abdominal stab wounds and, potential injuries in multiple body cavities.

    Science.gov (United States)

    Clarke, Damian L; Gall, Tamara M H; Thomson, Sandie R

    2011-05-01

    In the setting of the hypovolaemic patient with a thoraco-abdominal stab wound and potential injuries in both the chest and abdomen, deciding which cavity to explore first may be difficult.Opening the incorrect body cavity can delay control of tamponade or haemorrhage and exacerbate hypothermia and fluid shifts. This situation has been described as one of double jeopardy. All stab victims from July 2007 to July 2009 requiring a thoracotomy and laparotomy at the same operation were identified from a database. Demographics, site and nature of injuries, admission observations and investigations as well as operative sequence were recorded. Correct sequencing was defined as first opening the cavity with most lethal injury. Incorrect sequencing was defined as opening a cavity and finding either no injury or an injury of less severity than a simultaneous injury in the unopened cavity. The primary outcome was survival or death. Sixteen stab victims underwent thoracotomy and laparotomy during the same operation. All were male with an age range of 18–40 (mean/median 27). Median systolic blood pressure on presentation was 90 mm Hg. (quartile range 80–90 mm Hg). Median base excess was 6.5 (quartile range 12 to 2.2). All the deaths were the result of cardiac injuries. Incorrect sequencing occurred in four patients (25%). In this group there were four negative abdominal explorations prior to thoracotomy with two deaths. There was one death in the correct sequencing group. Incorrect sequencing in stab victims who require both thoracotomy and laparotomy at the same sitting is associated with a high mortality. This is especially true when the abdomen is incorrectly entered first whilst the life threatening pathology is in the chest. Clinical signs may be confusing, leading to incorrect sequencing of exploration. The common causes for confusion include failure to appreciate that cardiac tamponade does not present with bleeding and difficulty in assessing peritonism in an

  9. 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

  10. Benign Osteoblastoma Located in the Parietal Bone

    OpenAIRE

    Lee, Yong Gun; Cho, Chang Won

    2010-01-01

    Benign osteoblastoma is an uncommon primary bone tumor, extremely rare in calvarium. We present a case of a 25-year-old female with an osteoblastoma of parietal bone which was totally resected. The authors discussed the clinical presentation, radiographic finding, differential diagnosis and management of the benign calvarial osteoblastoma with a review of the literature.

  11. Mathematical description of ignition, combustion and propagation of detonation in reacting gas mixtures in the presence of micro- and nanoparticles

    Science.gov (United States)

    Fedorov, A. V.; Tropin, D. A.

    2017-10-01

    The physical and mathematical models for the description of the processes of ignition, combustion and propagation of detonation in mixtures of hydrogen-oxygen, methane-oxygen and silane-air in the presence of inert micro- and nanoparticles were proposed. On the basis of these models the dependencies of detonation velocity deficit vs the size and concentration of inert micro- and nanoparticles were found. Two modes of detonation flows in gas suspensions of reactive gases and inert nanoparticles were revealed: - propagation of weak detonation wave in the gas suspension, - destruction of the detonation process. It was determined that the mechanisms of detonation suppression by micro- and nanoparticles are closed and lies in the splitting of a detonation wave to frozen shock wave and ignition and combustion wave. Concentration limits of detonation were calculated. It turned out that in the transition from microparticles to nanoparticles the detonation suppression efficiency does not increase.

  12. 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.

  13. Polar Coordinate Lattice Boltzmann Kinetic Modeling of Detonation Phenomena

    International Nuclear Information System (INIS)

    Lin Chuan-Dong; Li Ying-Jun; Xu Ai-Guo; Zhang Guang-Cai

    2014-01-01

    A novel polar coordinate lattice Boltzmann kinetic model for detonation phenomena is presented and applied to investigate typical implosion and explosion processes. In this model, the change of discrete distribution function due to local chemical reaction is dynamically coupled into the modified lattice Boltzmann equation which could recover the Navier—Stokes equations, including contribution of chemical reaction, via the Chapman—Enskog expansion. For the numerical investigations, the main focuses are the nonequilibrium behaviors in these processes. The system at the disc center is always in its thermodynamic equilibrium in the highly symmetric case. The internal kinetic energies in different degrees of freedom around the detonation front do not coincide. The dependence of the reaction rate on the pressure, influences of the shock strength and reaction rate on the departure amplitude of the system from its local thermodynamic equilibrium are probed. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

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

    International Nuclear Information System (INIS)

    Casey, Leslie A.

    2014-01-01

    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. 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.

  16. 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.

  17. Directly thiolated modification onto the surface of detonation nanodiamonds.

    Science.gov (United States)

    Hsu, Ming-Hua; Chuang, Hong; Cheng, Fong-Yu; Huang, Ying-Pei; Han, Chien-Chung; Chen, Jiun-Yu; Huang, Su-Chin; Chen, Jen-Kun; Wu, Dian-Syue; Chu, Hsueh-Liang; Chang, Chia-Ching

    2014-05-28

    An efficient method for modifying the surface of detonation nanodiamonds (5 and 100 nm) with thiol groups (-SH) by using an organic chemistry strategy is presented herein. Thiolated nanodiamonds were characterized by spectroscopic techniques, and the atomic percentage of sulfur was analyzed by elemental analysis and X-ray photoelectron spectroscopy. The conjugation between thiolated nanodiamonds and gold nanoparticles was elucidated by transmission electron microscopy and UV-vis spectrometry. Moreover, the material did not show significant cytotoxicity to the human lung carcinoma cell line and may prospectively be applied in bioconjugated technology. The new method that we elucidated may significantly improve the approach to surface modification of detonation nanodiamonds and build up a new platform for the application of nanodiamonds.

  18. 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.

  19. Effect of turbulence on deflagration to detonation transition

    International Nuclear Information System (INIS)

    Radford, D.D.; Chan, C.K.; Azad, R.S.

    1995-01-01

    The interaction of a turbulent jet and an expanding flame kernel was examined using spark-schlieren photography and piezoelectric pressure transducers. Experiments were performed in a 9 by 9 cm, 4-m-long shock channel. Results show that an expanding flame kernel can be locally, or partially, quenched by flame stretching. The mixing of the hot combustion products, containing reactive species, with the unburnt gas in the turbulent flame-jet, created pockets of sensitized mixture. The subsequent re-ignition of the sensitized mixture could result in a local explosion. In a number of experiments the blast waves produced in the local explosion developed into detonation waves. A local explosion occurred only if there was partial quenching of the flame kernel. Partial quenching occurs when the Karlovitz-Kovaszney factor approaches unity and, therefore, it is possible to establish a set of conditions in terms of turbulent parameters for the transition to detonation. (author). 16 refs., 13 figs

  20. Evaluation of the effects of detonation in a spherical bomb

    International Nuclear Information System (INIS)

    Kurylo, J.; Oppenheim, A.K.

    1979-11-01

    An analysis is presented of the time-dependent pressure forces and impulse loadings on the walls of the hemispherical dome of a nuclear reactor pressure vessel arising from a centrally ignited hydrogen-oxygen detonation. Investigated in this context are the effects of richness of the detonable gas mixture as well as those due to the inclusion of water vapor. In the analysis the gas mixture was treated as a perfect gas, and the partial differential equations governing the gasdynamic flow were integrated using the CLOUD CODE - a finite-difference technique set in Lagrangian coordinates and incorporating the smoothing action of artificial viscosity. The most interesting results pertain to the ringing of pressure pulses at the walls. Their frequency is quite uniform, and their pressure peaks, at levels significantly higher than that of combustion at constant volume, decay at a negligible rate

  1. Long-term worldwide effects of multiple nuclear weapons detonations

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The NAS report, issued in 1975 shocked the scientific community by suggesting that detonation of a fraction of the world's nuclear arsenal (10 4 megatons) could produce a major, 30-70%, reduction in stratospheric ozone, lasting a year or more. The consequences of such a reduction in the natural barrier to solar ultraviolet radiation include the potential extinction of mammalian life. The summary section of the 1975 report is reprinted here

  2. Flame acceleration and transition to detonation in ducts

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G. [Queen' s University, 130 Stuart Street, Kingston, Ontario (Canada); Dorofeev, S. [FM Global, 1151 Boston-Providence Turnpike, P.O. Box 910, Norwood, MA 02062 (United States)

    2008-08-15

    This paper reviews the state of knowledge on flame acceleration and deflagration-to-detonation transition (DDT) in smooth ducts and ducts equipped with turbulence-producing obstacles. The objective is to bring to light the basic understanding of the phenomenon and its application to explosion safety. The scope of the review is restricted to homogeneous gas-phase combustion with emphasis placed on experimental investigation. (author)

  3. The unique signal concept for detonation safety in nuclear weapons

    Energy Technology Data Exchange (ETDEWEB)

    Spray, S.D.; Cooper, J.A.

    1993-06-01

    The purpose of a unique signal (UQS) in a nuclear weapon system is to provide an unambiguous communication of intent to detonate from the UQS information input source device to a stronglink safety device in the weapon in a manner that is highly unlikely to be duplicated or simulated in normal environments and in a broad range of ill-defined abnormal environments. This report presents safety considerations for the design and implementation of UQSs in the context of the overall safety system.

  4. Descriptive summary of airblast effects for buried cratering detonations

    International Nuclear Information System (INIS)

    Snell, C.M.

    1976-01-01

    Detonation of a buried nuclear or high-explosive charge induces an airblast signal in the air above the explosion site. The waveform of this signal may be complex, involving features created by ground surface motion effects, venting and expansion of gas from the explosive cavity, and energy release through an unstemmed or partly stemmed emplacement hole. The basic physical mechanisms responsible for the airblast pulse and some of the techniques commonly used to predict airblast effects are described

  5. Initial hydrogen detonation data from the High-Temperature Combustion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ginsberg, T.; Ciccarelli, G.; Boccio, J. [and others

    1994-12-31

    The Brookhaven National Laboratory High-Temperature Combustion Facility (HTCF) is described and data from initial hydrogen detonation experiments are presented. Initial phase of the inherent detonability experimental program is described. Test gases thus far tested are hydrogen-air mixtures at one atmosphere initial pressure and temperatures 300K-650K. Detonation pressure, wave speed, and detonation cell size were measured. Data were consistent with earlier SSDA (small-scale development apparatus) test results. HTCF results confirm the conclusion from the SSDA program that the gas temperature decreases the cell size and, therefore, increases the sensitivity of mixtures to detonation. Data from the larger HTCF test vessel, however, also demonstrates that the effect of increased scale is to extend the range of detonable mixtures to lower concentration.

  6. On detonation initiation by a temperature gradient for a detailed chemical reaction models

    International Nuclear Information System (INIS)

    Liberman, M.A.; Kiverin, A.D.; Ivanov, M.F.

    2011-01-01

    The evolution from a temperature gradient to a detonation is investigated for combustion mixture whose chemistry is governed by a detailed chemical kinetics. We show that a detailed chemical reaction model has a profound effect on the spontaneous wave concept for detonation initiation by a gradient of reactivity. The evolution to detonation due to a temperature gradient is considered for hydrogen-oxygen and hydrogen-air mixtures at different initial pressures. It is shown that the minimal length of the temperature gradient for which a detonation can be ignited is much larger than that predicted from a one-step chemical model. - Highlights: → We study detonation initiation by temperature gradient for detailed chemical models. → Detailed chemical models have a profound effect on the spontaneous wave concept. → Initiating detonation by temperature gradient differs from one-step model. → In real fuels DDT can not be initiated by temperature gradient.

  7. Munitions having an insensitive detonator system for initiating large failure diameter explosives

    Science.gov (United States)

    Perry, III, William Leroy

    2015-08-04

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

  8. Detonation Initiation by Shock Reflection from an Orifice Plate

    Science.gov (United States)

    Ciccarelli, G.; de Witt, B.

    2006-07-01

    Results from an experimental investigation of the interaction of a “non-ideal” shock wave and a single obstacle are reported. The shock wave is produced ahead of an accelerated flame in a 14 cm inner-diameter tube partially filled with orifice plates. The shock wave interacts with a single larger blockage orifice plate placed 15-45 cm after the last orifice plate in the flame acceleration section of the tube. Experiments were performed with stoichiometric ethylene-oxygen mixtures with varying amounts of nitrogen dilution at atmospheric pressure and temperature. The critical nitrogen dilution was found for detonation initiation. It is shown that detonation initiation occurs if the chemical induction time based on the reflected shock state is shorter than the time required for an acoustic wave to traverse the orifice plate upstream surface, from the inner to the outer diameter. The similarity between the present results and those obtained from previous investigators looking at detonation initiation by ideal shock reflection produced in a shock tube indicates that the phenomenon is not sensitive to the detailed structure of the shock front but only on the average shock strength.

  9. Equation of state, initiation, and detonation of pure ammonium nitrate

    Science.gov (United States)

    Robbins, D. L.; Sheffield, S. A.; Dattelbaum, D. M.; Velisavljevic, N.; Stahl, D. B.

    2009-06-01

    Ammonium nitrate (AN) is a widely used fertilizer and mining explosive throughout the world. One of the more common explosives using AN is called ANFO, a mixture of AN prills and fuel oil in a 94:6 ratio by weight. The AN prills are specially made to absorb the fuel oil, forming a mixture that reacts under shock loading through a diffusion-controlled process, resulting in a non-ideal explosive with detonation velocities around 4 km/s. While there are a number of studies on ANFO, there are only a few studies relating to the equation of state (EOS) and detonation properties of pure AN - resulting mainly from studies of accidents that have occurred during transportation of large quantities of AN. We present the results of a series of gas gun-driven plate impact experiments on pressed AN ranging in density from 1.72 to 0.9 g/cm^3. Several of the high density experiments were performed in front surface impact geometry, in which pressed AN disks were built into the projectile front and impacted onto LiF windows. Additional experiments at low density have been done in ``half cell'' multiple magnetic gauge gun experiments. From this work a complete unreacted EOS has been developed, as well as some initiation and detonation information. Additional high pressure x-ray diffraction experiments in diamond anvil cells have provided a static isotherm for AN.

  10. 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.

  11. Modification of the colony tower for the Rio Blanco detonation

    International Nuclear Information System (INIS)

    Blume, J.A.; Freeman, S.A.; Honda, K.K.; Lee, L.A.

    1975-01-01

    Supplemental structural bracing was designed and installed for the 180-ft-tall Colony Tower, an experimental oil shale processing retort structure, in anticipation of its lateral response to the Rio Blanco detonation. The tower is a steel structure with both horizontal and vertical diagonal bracing. Data obtained from the earlier Project Rulison detonation indicated that an evaluation study was necessary. Design criteria that would provide an adequate margin of safety were developed based on predicted Rio Blanco ground motion. The evaluation of the unmodified structure showed that several bracing members would be subjected to forces exceeding their yield strength, and some would reach a level at which failure could occur. Further analyses were made with assumed modified bracing members. A final scheme for modified vertical bracing was established and installed. After modification, the response of the tower during the Rio Blanco detonation was measured by instruments on the ground and at various locations on the tower, and no evidence of damage was discovered. The modification of the Colony Tower and the procedures used to determine these modifications show the usefulness of current ground motion and structural response prediction technology for forecasting dynamic behavior of important structures subjected to ground motion from underground nuclear explosions. (auth)

  12. 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.

  13. Experimental investigation of detonation waves instabilities in liquid high explosives

    Science.gov (United States)

    Sosikov, V. A.; Torunov, S. I.; Utkin, A. V.; Mochalova, V. M.; Rapota, D. Yu

    2018-01-01

    Experimental investigation of unstable detonation front structure in mixtures of liquid high explosives (nitromethane and FEFO—bis-(2-fluor-2.2-dinitroethyl)-formal) with inert diluents (acetone, methanol, DETA—diethylene triamine) has been carried out. Inhomogeneities have been registered by electro-optical camera NANOGATE 4BP allowing to make 4 frames with the exposure time 10 ns. According to experimental results the detonation front in nitromethane–acetone mixture is unstable. It is evident that pulsations on detonation front do not form spatial periodic structure and their dimensions differ several times. But mean longitudinal size of pulsation is about 500 μm at 20 wt% of acetone concentration. This means that the typical size of cell equals to reaction zone width. The same structure of cellular front have been registered in 70/30 FEFO–methanol mixture. Second kind of instability, failure waves, was observed in neat nitromethane at the free surface. In this case the stability loss result in turbulent flow which is clearly detected in the shots obtained. Adding small amount of DETA (0.5 wt%) results in disappearance of the failure waves and flow stabilization. The effect is caused by the fact that DETA sharply accelerates initial rate of chemical reaction because it is sensitizer for nitromethane.

  14. 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.

  15. Detonation of porous, high-HMX, nitroglycerine containing propellant by low-level shock

    Energy Technology Data Exchange (ETDEWEB)

    Green, L.G.; Chambers, E.S.; Lee, E.L.

    1982-04-01

    The sympathetic detonation throw distances to impact damaged propellant were measured. Reflected pressures at the threshold distances are about the same as pressures generated in piston compaction experiments on porous propellant at threshold piston velocities. Run distance to detonation experiments done on porous propellant using a steel impactor represent a final state from which run up to detonation occurs in both piston compaction experiments and in classical DDT experiments, which are seen as combustion driven mechanical compactions.

  16. Detonation of porous, high HMX, nitroglycerine containing propellant by low level shock

    Energy Technology Data Exchange (ETDEWEB)

    Green, L.G.; Chambers, E.S.; Lee, E.L.; Brown, B.

    1982-01-01

    We have measured sympathetic detonation throw distances to impact damaged propellant. Reflected pressures at the threshold distances are about the same as pressures generated in piston compaction experiments on porous propellant at threshold piston velocities. Run distance to detonation experiments done on porous propellant using a steel impactor represent a final state from which run up to detonation occurs in both piston compaction experiments and in classical DDT experiments, which are seen as combustion driven mechanical compactions.

  17. Studies Chapman-Jouguet Oblique Detonation Waves Sustained bu Hypersonic Free Projectilies

    OpenAIRE

    笠原, 次郎; 新井, 隆景; 高沢, 光貴; 松尾, 亜紀子

    2001-01-01

    Five-mm-diameter projectiles, whose speed was beyond the Chapman-Jouguet (C-J) detonation speed, were fired into mixtures containing stoichiometric hydrogen-oxygen gases plus argon diluents. The flowfield around the projectile was visualized using a CCD cameta. We measured the minimum normal velocity components of detonation waves around the projectiles and the curvature radius of a bow detonation wave near the projectile tip. From these experimental results we concluded that the steady-state...

  18. 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.

  19. Formic Acid Investigation for the Prediction of High Explosive Detonation Properties and Performance

    Science.gov (United States)

    2010-07-01

    Picatinny Arsenal, NJ, January 1993. 4. Cowperthwaite, M. and Zwisler, W. H., "The JCZ Equations of State for Detonation Products and Their...AD AD-E403 298 Technical Report ARMET-TR-10006 FORMIC ACID INVESTIGATION FOR THE PREDICTION OF HIGH EXPLOSIVE DETONATION PROPERTIES AND...DATES COVERED {From - To) 4. TITLE AND SUBTITLE FORMIC ACID INVESTIGATION FOR THE PREDICTION OF HIGH EXPLOSIVE DETONATION PROPERTIES AND PERFORMANCE

  20. A stab wound to the axilla illustrating the importance of brachial plexus anatomy in an emergency context: a case report.

    Science.gov (United States)

    Casal, Diogo; Cunha, Teresa; Pais, Diogo; Iria, Inês; Angélica-Almeida, Maria; Millan, Gerardo; Videira-Castro, José; Goyri-O'Neill, João

    2017-01-04

    Although open injuries involving the brachial plexus are relatively uncommon, they can lead to permanent disability and even be life threatening if accompanied by vascular damage. We present a case report of a brachial plexus injury in which the urgency of the situation precluded the use of any ancillary diagnostic examinations and forced a rapid clinical assessment. We report a case of a Portuguese man who had a stabbing injury at the base of his left axilla. On observation in our emergency room an acute venous type of bleeding was present at the wound site and, as a result of refractory hypotension after initial management with fluids administered intravenously, he was immediately carried to our operating room. During the course of transportation, we observed that he presented hypoesthesia of the medial aspect of his arm and forearm, as well as of the ulnar side of his hand and of the palmar aspect of the last three digits and of the dorsal aspect of the last two digits. Moreover, he was not able to actively flex the joints of his middle, ring, and small fingers or to adduct or abduct all fingers. Exclusively relying on our anatomical knowledge of the axillary region, the site of the stabbing wound, and the physical neurologic examination, we were able to unequivocally pinpoint the place of the injury between the anterior division of the lower trunk of his brachial plexus and the proximal portion of the following nerves: ulnar, medial cutaneous of his arm and forearm, and the medial aspect of his median nerve. Surgery revealed a longitudinal laceration of the posterior aspect of his axillary vein, and confirmed a complete section of his ulnar nerve, his medial brachial and antebrachial cutaneous nerves, and an incomplete section of the ulnar aspect of his median nerve. All structures were repaired microsurgically. Three years after the surgery he showed a good functional outcome. We believe that this case report illustrates the relevance of a sound anatomical

  1. 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.

  2. Management of Benign Biliary Strictures

    International Nuclear Information System (INIS)

    Laasch, Hans-Ulrich; Martin, Derrick F.

    2002-01-01

    Benign biliary strictures are most commonly a consequence of injury at laparoscopic cholecystectomy or fibrosis after biliary-enteric anastomosis. These strictures are notoriously difficult to treat and traditionally are managed by resection and fashioning of acholedocho- or hepato-jejunostomy. Promising results are being achieved with newer minimally invasive techniques using endoscopic or percutaneous dilatation and/or stenting and these are likely to play an increasing role in the management. Even low-grade biliary obstruction carries the risks of stone formation, ascending cholangitis and hepatic cirrhosis and it is important to identify and treat this group of patients. There is currently no consensus on which patient should have what type of procedure, and the full range of techniques may not be available in all hospitals. Careful assessment of the risks and likely benefits have to be made on an individual basis. This article reviews the current literature and discusses the options available. The techniques of endoscopic and percutaneous dilatation and stenting are described with evaluation of the likely success and complication rates and compared to the gold standard of biliary-enteric anastomosis

  3. Recurrent Benign Salivary Gland Neoplasms.

    Science.gov (United States)

    Witt, Robert Lee; Nicolai, Piero

    2016-01-01

    The most important causes of recurrence of benign pleomorphic adenoma are enucleation with intraoperative spillage and incomplete tumor excision in association with characteristic histologic findings for the lesion (incomplete pseudocapsule and the presence of pseudopodia). Most recurrent pleomorphic adenomas (RPAs) are multinodular. MRI is the imaging method of choice for their assessment. Nerve integrity monitoring may reduce morbidity of RPA surgery. Although treatment of RPA must be individualized, total parotidectomy is generally recommended given the multicentricity of the lesions. However, surgery alone may be inadequate for controlling RPA over the long term. There is growing evidence from retrospective series that postoperative radiotherapy results in significantly better local control. A high percentage of RPAs are incurable. All patients should therefore be informed about the possibility of needing multiple treatment procedures, with possible impairment of facial nerve function, and radiation therapy for RPA. Reappearance of Warthin tumor is a metachronous occurrence of a new focus or residual incomplete excision of all primary multicentric foci of Warthin tumor. Selected cases can be observed. Conservative surgical management can include partial superficial parotidectomy or extracapsular dissection. Not uncommonly, other major and minor salivary gland neoplasms, including myoepithelioma, basal cell adenoma, oncocytoma, canalicular adenoma, cystadenoma, and ductal papilloma, follow an indolent course after surgical resection, with rare cases of recurrence. © 2016 S. Karger AG, Basel.

  4. 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.

  5. Initial hydrogen detonation data from the High-Temperature Combustion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ginsberg, T.; Ciccarelli, G.; Boccio, J.; Curtiss, J.; Economos, C.; Finfrock, C.; Gerlach, L.; Jahelka, J.; Kinoshita, M.; Sato, K. [Brookhaven National Lab., Upton, NY (United States)

    1994-10-01

    The BNL High-Temperature Combustion Facility (HTCF) has been constructed as an experimental research tool for the purpose of characterizing the influence of elevated gas mixture temperature on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for deflagration-to-detonation transition (DDT), on the phenomena of hot jet initiation of detonation, and on detonation transmission. This summary presents a brief description of the facility, describes the initial test program, and presents results of experiments performed as part of the initial phase of the planned testing program.

  6. Initial hydrogen detonation data from the High-Temperature Combustion Facility

    International Nuclear Information System (INIS)

    Ginsberg, T.; Ciccarelli, G.; Boccio, J.; Curtiss, J.; Economos, C.; Finfrock, C.; Gerlach, L.; Jahelka, J.; Kinoshita, M.; Sato, K.

    1994-01-01

    The BNL High-Temperature Combustion Facility (HTCF) has been constructed as an experimental research tool for the purpose of characterizing the influence of elevated gas mixture temperature on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for deflagration-to-detonation transition (DDT), on the phenomena of hot jet initiation of detonation, and on detonation transmission. This summary presents a brief description of the facility, describes the initial test program, and presents results of experiments performed as part of the initial phase of the planned testing program

  7. 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.

  8. Ignition and growth reactive flow modeling of recent HMX/TATB detonation experiments

    Science.gov (United States)

    Tarver, Craig M.

    2017-01-01

    Two experimental studies in which faster HMX detonation waves produced oblique detonation waves in adjoining slower detonating TATB charges were modeled using the Ignition and Growth (I&G) reactive flow detonation model parameters for PBX 9501 (95% HMX / 2.5% Estane / 2.5% BDNPA/F) and PBX 9502 (95% TATB / 5% Kel-F binder). Matignon et al. used X1 explosive (96% HMX / 4% binder) to drive an oblique detonation wave into an attached charge of T2 explosive (97% TATB / 3% binder). The flow angles were measured in the T2 shock initiation region and in steady T2 detonation. Anderson et al. used detonating PBX 9501 slabs of various thicknesses ranging from 0.56 mm to 2.5 mm to create oblique detonation waves in 8 mm thick slabs of PBX 9502. Several diagnostics were employed to: photograph the waves; measure detonation velocities and flow angles; and determine the output of the PBX 9501 slabs, the PBX 9502 slabs, and the "initiation regions" using LiF windows and PDV probes.

  9. Detonation velocity of pure and mixed CHNO explosives at maximum nominal density.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2007-03-22

    In this paper, a simple approach is introduced to predict detonation velocity of pure and mixed explosives at maximum nominal density. This technique may be applied to any pure or mixed explosives that contain elements of carbon, hydrogen, nitrogen and oxygen. The new method requires only elemental composition and some specific structural parameters. The introduced correlation can easily be applied for determining maximum expected detonation velocity of any new CHNO explosive without using its crystal density. Calculated detonation velocities by this procedure for both pure and composite explosive formulations show good agreement with respect to measured detonation velocity at maximum nominal density.

  10. 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.

  11. Continuous spin detonation of a syngas-air mixture in a plane-radial vortex combustor

    Science.gov (United States)

    Bykovskii, F. A.; Zhdan, S. A.; Vedernikov, E. F.

    2017-09-01

    Continuous spin detonation in syngas-air mixtures with three different syngas compositions [CO]/[H2] = 1/3, 1/2, and 1/1 is experimentally studied in a flow-type radial vortex combustor 500 mm in diameter. It is found that all these mixtures with three syngas compositions can be effectively burned in air in the detonation regime. Transverse detonation waves of identical structure are detected. The limits of existence of continuous detonation in terms of the specific flow rates of the mixtures (minimum values) are determined.

  12. 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)

  13. Benign paroxysmal positional vertigo in Parkinson's disease.

    Science.gov (United States)

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

    2013-12-01

    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. To assess the prevalence of benign paroxysmal positional vertigo in patients with Parkinson's disease, with and without dizziness. 305 consecutive outpatients with PD completed the Movement Disorders Society-sponsored revision of the Unified Parkinsons' Disease Rating Scale-motor score, the Dizziness Handicap Inventory, the Dix-Hallpike maneuver and a test for orthostatic hypotension. When positive for benign paroxysmal positional vertigo, a repositioning maneuver was performed. Patients were followed for three months to determine the clinical response. 305 patients responded (186 men (61%), mean age 70.5 years (Standard Deviation 9.5 years)), of whom 151 (49%) complained of dizziness. 57 (38%) of the dizzy patients appeared to have orthostatic hypotension; 12 patients (8%) had a classical but previously unrecognized benign paroxysmal positional vertigo. A further four patients (3%) had a more atypical presentation of benign paroxysmal positional vertigo. Three months after treatment, 11 (92%) of patients with classical benign paroxysmal positional vertigo were almost or completely without complaints. We found no 'hidden' benign paroxysmal positional vertigo among patients without dizziness. The prevalence of benign paroxysmal positional vertigo among all patients with PD was 5.3%. Among Parkinson patients with symptoms of dizziness, up to 11% may have benign paroxysmal positional vertigo, which can be treated easily and successfully. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  14. [Research on diagnosis of gas-liquid detonation exhaust based on double optical path absortion spectroscopy technique].

    Science.gov (United States)

    Lü, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-03-01

    The effect detection of detonation exhaust can provide measurement data for exploring the formation mechanism of detonation, the promotion of detonation efficiency and the reduction of fuel waste. Based on tunable diode laser absorption spectroscopy technique combined with double optical path cross-correlation algorithm, the article raises the diagnosis method to realize the on-line testing of detonation exhaust velocity, temperature and H2O gas concentration. The double optical path testing system is designed and set up for the valveless pulse detonation engine with the diameter of 80 mm. By scanning H2O absorption lines of 1343nm with a high frequency of 50 kHz, the on-line detection of gas-liquid pulse detonation exhaust is realized. The results show that the optical testing system based on tunable diode laser absorption spectroscopy technique can capture the detailed characteristics of pulse detonation exhaust in the transient process of detonation. The duration of single detonation is 85 ms under laboratory conditions, among which supersonic injection time is 5.7 ms and subsonic injection time is 19.3 ms. The valveless pulse detonation engine used can work under frequency of 11 Hz. The velocity of detonation overflowing the detonation tube is 1,172 m x s(-1), the maximum temperature of detonation exhaust near the nozzle is 2 412 K. There is a transitory platform in the velocity curve as well as the temperature curve. H2O gas concentration changes between 0-7% during detonation under experimental conditions. The research can provide measurement data for the detonation process diagnosis and analysis, which is of significance to advance the detonation mechanism research and promote the research of pulse detonation engine control technology.

  15. 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. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Selective non-operative management of stab wounds to the posterior abdomen is safe: the Pietermaritzburg experience.

    Science.gov (United States)

    Kong, Victor; Oosthuizen, George; Sartorius, Benn; Clarke, Damian

    2015-09-01

    The selective non-operative management (SNOM) of stab injuries of the anterior abdomen is well established, but its application to the posterior abdomen remains controversial. A retrospective review of 1013 patients was undertaken at a major trauma service in South Africa over a five-year period. Ninety per cent of patients were males, and the mean age was 25 years. The mean time from injury to presentation was 4h and 73% of all injuries were inflicted by knives. A total of 9% (93) of patients required a laparotomy [Group A] and 82% (833) were successfully observed without the need for operative intervention [Group B]. CT imaging was performed on 52 patients (5%) who had haematuria [Group C], 25 (3%) who had neurological deficits [Group D], and 10 (1%) with retained weapon injuries [Group E]. The accuracy of physical examination for identifying the presence of organ injury was 88%. All observed patients who required laparotomy declared themselves within 24h. There were no mortalities as direct result of our current management protocol. Selective management based on active clinical observation and serial physical examination is safe, and when coupled with the judicious use of advanced imaging, is a prudent and reliable approach in a resource constrained environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Thermotherapy and thermoablation for benign prostatic hyperplasia

    NARCIS (Netherlands)

    Gravas, Stavros; Laguna, Pilar; de la Rosette, Jean

    2003-01-01

    PURPOSE OF REVIEW: From all the available thermoablative methods for the treatment of symptomatic benign prostatic hyperplasia, transurethral microwave thermotherapy is considered as standard in minimally invasive management. The literature is enriched by several new studies on transurethral

  19. Genetics Home Reference: benign recurrent intrahepatic cholestasis

    Science.gov (United States)

    ... expand/collapse boxes. 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 ...

  20. Immunoprofile of benign and malignant fibrohistiocytic tumors.

    Science.gov (United States)

    Regezi, J A; Zarbo, R J; Tomich, C E; Lloyd, R V; Courtney, R M; Crissman, J D

    1987-05-01

    Formalin-fixed, paraffin-embedded tissue sections from 26 malignant fibrous histiocytomas (MFH) and 61 benign fibrohistiocytic proliferations (BFHP) were evaluated immunohistochemically. An avidinbiotin-peroxidase technique was used to determine immunoreactivity for alpha-1 antichymotrypsin, muramidase, HLA-DR, leucocyte common antigen, S-100 protein, vimentin, desmin, and keratin. MFHs were consistently positive for ACT and vimentin and inconsistently reactive for the other antigens. MFHs were negative for LCA suggesting a mesenchymal origin for these lesions. In the MFH histologic subtypes, antigen expression was not significantly different to be useful in their classification. Also no distinctive pattern emerged relative to immunoreactivity and tumor location. The benign lesions, giant cell tumor of tendon sheath, dermatofibroma, and oral benign fibrous histiocytoma differed from the MFHs in that they were often LCA positive, suggesting origin from hematopoetic mononuclear-macrophages. The immunoprofiles of peripheral fibromas and "giant cell" fibromas were felt to be consistent with origin from mesenchymal cells. Several of the antigens studied could be used to differentiate the benign lesions studied from other benign neoplasms. The antigens were, however, of little value in separation of benign and malignant lesions.

  1. Influence of physical properties of explosives on the characteristics of detonation waves: a molecular-dynamics study

    OpenAIRE

    Utkin, A.; Golovnev, I.; Fomin, V.

    2004-01-01

    In the present study, the molecular-dynamics method was used to investigate into the effect of atomic mass on the detonation wave processes in molecular crystals. The characteristics of interest were the detonation-wave propagation velocity, the detonation-wave structure, the delay time of the chemical reaction, and macroscopic energy characteristics of the disturbed region. A comparison of gained molecular-dynamics data with the predictions of the continual theory of detonation is given; in ...

  2. Factors influencing the reliability of non-electric detonating circuit in underground uranium mines and preventive measures of misfiring

    International Nuclear Information System (INIS)

    Li Qin

    2010-01-01

    Characteristics of non-electric detonating circuit are introduced. The main factors influencing the reliability of non-electric detonating circuit are described. Taking an underground blasting of a uranium mine for example, the reliability of various kinds of detonating network system is calculated using the reliability theory and numerical analysis method. The reasons that cause the misfiring in non-electric detonating circuit system are analyzed, and preventive measures are put forward.(authors)

  3. 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.

  4. Numerical prediction of steady-state detonation properties of condensed-phase explosives.

    Science.gov (United States)

    Cengiz, F; Ulas, A

    2009-12-30

    Within the scope of this study, a computer code named BARUT-X has been developed to calculate the detonation properties of C-H-N-O based condensed-phase explosives using the Chapman-Jouguet (C-J) theory. Determination of the detonation properties is performed in chemical equilibrium and steady-state conditions. Unlike other codes in the literature which use steepest descent optimization method, BARUT-X uses a nonlinear optimization code based on Generalized Reduced Gradient algorithm to compute the equilibrium composition of the detonation products. This optimization code provides a higher level of robustness of the solutions and global optimum determination efficiency. The Becker-Kistiakowsky-Wilson's (BKW) equation of state (EOS) is applied to the high-density gaseous detonation products at high pressures. BARUT-X uses RDX, TNT, BKWR, and BKWN set of constants in the BKW EOS. In addition, the Cowan-Fickett's EOS is applied for the compressible solid carbon in the detonation products. The calculated detonation properties for several condensed-phase explosives by BARUT-X have been compared with those computed by EXPLO5 and FORTRAN BKW codes as well as the experimental data in terms of detonation velocity and detonation pressure. Satisfactory agreement is obtained from these comparisons.

  5. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Science.gov (United States)

    2010-07-01

    ... Blasting § 75.1312 Explosives and detonators in underground magazines. (a) The quantity of explosives kept... roadways and any source of electric current; (2) Located out of the direct line of the forces from blasting... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and detonators in underground...

  6. Imaging malignant and apparent malignant transformation of benign gynaecological disease

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.Y.; Poder, L.; Qayyum, A.; Wang, Z.J.; Yeh, B.M. [Department of Radiology, University of California San Francisco, San Francisco, CA (United States); Coakley, F.V., E-mail: Fergus.Coakley@radiology.ucsf.ed [Department of Radiology, University of California San Francisco, San Francisco, CA (United States)

    2010-12-15

    Common benign gynaecological diseases, such as leiomyoma, adenomyosis, endometriosis, and mature teratoma, rarely undergo malignant transformation. Benign transformations that may mimic malignancy include benign metastasizing leiomyoma, massive ovarian oedema, decidualization of endometrioma, and rupture of mature teratoma. The aim of this review is to provide a contemporary overview of imaging findings in malignant and apparent malignant transformation of benign gynaecological disease.

  7. MK-82 bomb characterization for the sympathetic detonation study

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, R.A.; Hantel, L.W.

    1988-01-01

    Optical, radiographic, and electronic pin techniques were used to evaluate the fragmentation of tail- and side-initiated MK-82 MOD 1 general purpose bombs. They were found to contain large voids, randomly located from bomb to bomb, in the Tritonal explosive fill. Characteristics of the void-side performance of the bomb were found to be as much as 10% different from the nonvoid side and were much less reproducible than the characteristics of the nonvoid side. The data collected will be useful in evaluating sympathetic detonation mitigation systems designed for use with the bombs. 12 figs., 3 tabs.

  8. 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

  9. Surface functionalization of detonation nanodiamonds by phosphonic dichloride derivatives.

    Science.gov (United States)

    Presti, Charlene; Alauzun, Johan G; Laurencin, Danielle; Mutin, P Hubert

    2014-08-05

    A new method for the functionalization of detonation nanodiamonds (DNDs) is proposed, on the basis of surface modification with phosphonic dichloride derivatives. DNDs were first modified by phenylphosphonic dichloride, and the grafting modes and hydrolytic stability under neutral conditions were investigated using (1)H, (13)C, and (31)P solid state NMR spectroscopy, Fourier transform infrared spectroscopy, as well as elemental analysis. Then, in order to illustrate the possibilities offered by this method, DNDs functionalized by mesityl imidazolium groups were obtained by postmodification of DNDs modified by 12-bromododecylphosphonic dichloride. The oxidative thermal stability of the functionalized DNDs was investigated using thermogravimetric analysis.

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

    International Nuclear Information System (INIS)

    Barrett, Christopher L.; Eubank, Stephen; Evrenosoglu, C. Yaman; Marathe, Achla; Marathe, Madhav V.; Phadke, Arun; Thorp, James; Vullikanti, Anil

    2013-01-01

    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. High-resolution electron microscopy of detonation nanodiamond

    International Nuclear Information System (INIS)

    Iakoubovskii, K; Mitsuishi, K; Furuya, K

    2008-01-01

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated

  12. High-resolution electron microscopy of detonation nanodiamond

    Energy Technology Data Exchange (ETDEWEB)

    Iakoubovskii, K; Mitsuishi, K [Quantum Dot Research Center, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan); Furuya, K [High Voltage Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan)], E-mail: Iakoubovskii.Konstantin@nims.go.jp

    2008-04-16

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated.

  13. 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.

  14. 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.

  15. INCREASING MEASUREMENT ACCURACY IN ELECTRO-OPTICAL METHOD FOR MEASURING VELOCITY OF DETONATION

    Directory of Open Access Journals (Sweden)

    Mario Dobrilović

    2014-12-01

    Full Text Available In addition to other detonation parameters detonation velocity is a value that provides indirect information on the strength i.e. brisance of an explosive and explosive performance. In addition to that, detonation velocity is a value which can be measured in a relatively simpler and more precise manner, by developed and accessible methods when compared to other detonation parameters Due to its simple use, compact instruments and satisfactory accuracy, electro-optical method of detonation velocity measurement is widely used. The paper describes the electro-optical measurement method and points out the factors that affect its accuracy. The accuracy of measurement is increased and measurement uncertainty is reduced by the measurement result analysis with the application of different measurement setups.

  16. 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

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

    Science.gov (United States)

    Saeidiborojeni, Hamid Reza; Moradinazar, Mehdi; Saeidiborojeni, Sepehr; Ahmadi, Alireza

    2013-01-01

    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. 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. 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. 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 complete injuries. Therefore, all the patients should be

  18. 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.

  19. Numerical simulation of nonlinear dynamics of 1D pulsating detonations

    Science.gov (United States)

    Borisov, S. P.; Kudryavtsev, A. N.

    2017-10-01

    The development of 1D instability of a detonation wave is numerically simulated for a two-stage chemical model. The shock-fitting approach is employed to track the leading detonation front. In order to determine its motion, the equation for the acceleration of the shock wave derived from the Rankine-Hugoniot conditions and the characteristic relations is integrated along with the reactive Euler equations. The fifth-order WENO scheme is used, time stepping is performed with the four-stage Runge-Kutta-Gill method. It is shown that in a certain range of parameters of the problem (the degree of overdrive f, the dissociation energy Ed and the activation energy Ea ), the Zeldovich-Neumann-Döring stationary solution is unstable with respect to 1D disturbances. The evolution of disturbances at later nonlinear stages is studied. Nonlinear saturation of the growth of disturbances leads to the formation of a stable limit cycle. When changing the parameters of the problem, the period doubling bifurcation can occur leading to the appearance of pulsations with two different maxima of the amplitude.

  20. 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.

  1. Detonation initiation in atomistic and mesoscopic simulation of porous explosives

    Science.gov (United States)

    Murzov, Semen; Zhakhovsky, Vasily

    2017-06-01

    Atomistic simulation of chemical reactions activated by shock compression is feasible at sub-nanosecond timescale, and molecular dynamics simulation indicates that the most energetic reactions accomplish within several tens of picosecond. This is too short time in comparison with microseconds required for experimental shock-to-detonation transition in real solid explosives with pores. Different types of hotspots were found in MD simulation of porous explosive described by AB model. Those types are categorized according to ratios between a characteristic time of reactions, a material motion time and a time of hotspot formation. The characteristic time of reaction is determined in MD simulation of isochoric thermal decomposition at different densities. To transfer such information into macroscopic spatial-time scale a simple model of material decomposition using a local thermodynamic and chemical equilibrium was developed. Consistent MD simulation and hydrodynamics modeling of AB samples by our smoothed particle hydrodynamic code are agreed well. The developed model was utilized in mesoscale modeling of shock-to-detonation transition in real porous explosives.

  2. Radiographic study for sympathetic detonation of 500-lb bombs

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, R.A.

    1989-01-01

    Flash radiography have determined the size and velocity vectors in the near field of fragments from tail- and side-initiated MK 82 MOD 1, general-purpose bombs. Excellent radiographs have been acquired from nine separate tests. Unlike arena tests, the radiographs were taken 75 to 125 cm from the case and show that the fragments peel off the case in long strips. A major concern in the design and execution of the experiments was the protection of the 450-kV x-ray heads and the film cassettes from fragments and blast produced by the 500-lb bombs. The velocity and size data, along with optical and electronic pin data, were used to characterize the fragments of the donor bomb in a donor-acceptor sympathetic detonation system study. The bombs were found to contain large shrink voids, randomly located from bomb to bomb, in the explosive Tritonal fill. Characteristics of the fragments from the void side if the bomb were found to be as much as 10% different from the nonvoid side and were much less reproducible than the fragments characteristics of the nonvoid side. The data collected will be useful in evaluating sympathetic detonation mitigation systems designed for use with the bombs. Such mitigation systems may be required for mass storage methods to meet the evolving insensitive munition requirements. 13 refs., 7 figs.

  3. Detonation initiation of heterogeneous melt-cast high explosives

    Science.gov (United States)

    Chuzeville, V.; Baudin, G.; Lefrançois, A.; Genetier, M.; Barbarin, Y.; Jacquet, L.; Lhopitault, J.-L.; Peix, J.; Boulanger, R.; Catoire, L.

    2017-01-01

    2,4,6-trinitrotoluene (TNT) is widely used in conventional and insensitive munitions as a fusible binder, commonly melt-cast with other explosives such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) or 3-nitro-1,2,4-triazol-one (NTO). In this paper, we study the shock-to-detonation transition phenomenon in two melt-cast high explosives (HE). We have performed plate impact tests on wedge samples to measure run-distance and time-to-detonation in order to establish the Pop-plot relation for several melt-cast HE. Highlighting the existence of the single curve buildup, we propose a two phase model based on a Zeldovich, Von-Neumann, Döring (ZND) approach where the deflagration fronts grow from the explosive grain boundaries. Knowing the grain size distribution, we calculate the deflagration velocities of the explosive charges as a function of shock pressure and explore the possible grain fragmentation.

  4. Deaggregation, Modification, and Developing Applications for Detonation Nanodiamond

    Science.gov (United States)

    Mochalin, Vadym

    2017-06-01

    Nanodiamond powder (ND) is one of the most promising materials for advanced composites and biomedical applications. It is also a commercial precursor for carbon nanoonions - material for high power micrometer size supercapacitors and potentially, Li-ion batteries. ND is produced by detonation of explosives with negative oxygen balance in a closed chamber, where extremely high pressures and temperatures develop during detonation. ND consists of diamond particles of 5 nm diameter, combining fully accessible large surface and rich and tailorable surface chemistry. ND has unique properties including optical, electrical, thermal, and mechanical, and is biocompatible and non-toxic. Due to numerous surface functional groups, ND has catalytic and electrochemical activity. Several techniques have been proposed for ND deaggregation based on milling with costly ceramic microbeads, leaving difficult to remove contaminations in the resulting ND suspension. We have recently discovered a novel, green technique for ND deaggregation using sonication in aqueous sodium chloride slurry. Upon completion of the process sodium chloride can be easily washed out with water leaving behind no contaminants and yielding stable single-digit ND colloids. Modification and development of applications for ND in composites, drug delivery, biomedical imaging, etc., will be also discussed.

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

    International Nuclear Information System (INIS)

    Trowbridge, L.D.

    2000-01-01

    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

  6. 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.

  7. [A study of the predictive value of the primary review and complementary examinations in assessing the need for surgery in patients with stab wounds in the torso].

    Science.gov (United States)

    Martínez Casas, Isidro; Sancho Insenser, Joan; Climent Agustín, Marta; Membrilla Fernández, Estela; Pons Fragero, María José; Guzmán Ahumada, Juan; Grande Posa, Luis

    2013-01-01

    Observation is the gold standard for stable patients with stab wounds. The aim of the study was to analyse the value of the primary review and complementary examinations to predict the need for surgery in stab wound patients in order to decrease observation times. A retrospective study of stab wound patients recorded in a database. Clinical and diagnostic workup parameters were analysed. The main variable was the need for surgery. A total of 198 patients were included between 2006 and 2009, with a mean injury severity score (ISS) of 7.8±7, and 0.5% mortality. More than half (52%) of the patients suffered multiple wounds. Wound distribution was 23% neck, 46% thorax and 31% abdomen. Surgery was required in 73 (37%) patients (59% immediate, 27% delayed and 14% delayed). The need for surgery was associated with a lower revised trauma score (RTS), evisceration, active bleeding, and fascial penetration. Initial and control haemoglobin levels were significantly lower in patients who required surgery. A positive computerised tomography (CT) scan was associated with surgery. There were complications in 18% of patients, and they were more frequent in those who underwent surgery. There was no difference in complication rates between immediate and delayed (P=.72). Surgery was finally required in 10% of the patients with no abnormalities in the primary review and diagnostic workup, and 6% of those developed complications. None of the parameters studied could individually assess the need for surgery. Primary and secondary reviews were the most important diagnostic tool, but CT scan should be used more often. An observation period of 24 hours is recommended in torso penetrating wounds. Copyright © 2012 AEC. Published by Elsevier Espana. All rights reserved.

  8. 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.

  9. Pharmacological treatment of the benign prostatic hyperplasia

    International Nuclear Information System (INIS)

    Perez Guerra, Yohani; Molina Cuevas, Vivian; Oyarzabal Yera, Ambar; Mas Ferreiro, Rosa

    2011-01-01

    Benign prostatic hyperplasia is a common disease in over 50 years-old men consisting in uncontrolled and benign growth of prostatic gland that leads to lower urinary tract symptoms. The etiology of benign prostatic hyperplasia is multifactoral involving the increased conversion of testosterone in dihydrotestosterone by the prostatic 5α-reductase action, which brought about events that encourage the prostate growth (static component) and the increase of the bladder and prostate smooth muscle tone (dynamic component) regulated by the aα 1 -adrenoceptors (ADR). The pharmacological treatment of the benign prostatic hyperplasia includes the prostatic 5aα-reductase inhibitors, the aα 1 -adrenoreceptor blockers, their combined therapy and the phytotherapy. This paper was aimed at presenting the most relevant aspects of the pharmacology of drugs used for treating the benign prostatic hyperplasia, and providing elements to analyze their efficacy, safety and tolerability. To this end, a review was made of the different drugs for the treatment of this pathology and they were grouped according to their mechanism of action. Natural products were included as lipid extracts from Serenoa repens and Pygeum africanum as well as D-004, a lipid extract from Roystonea regia fruits, with proved beneficial effects on the main etiological factors of benign prostatic hyperplasia. D-004 is a prostatic 5a-reductase inhibitor, an aα 1 -adrenoceptor antagonist, aα 5-lipooxygenase inhibitor and has antioxidant action, all of which reveals a multifactoral mechanism. The results achieved till now indicate that D-004 is a safe and well-tolerated product

  10. Benign breast lesions in Eastern Nigeria

    International Nuclear Information System (INIS)

    Anyikam, A.; Nzegwn, Martin A.; Olusina, Daniel B.; Okoye, I.; Ozumba, Ben C.

    2008-01-01

    Objective was to characterize benign breast diseases in Eastern Nigeria and to highlight the age variations of these lesions as base line data. The Department of Morbid Anatomy, University of Nigeria Teaching Hospital, Enugu caters for over 30 million African blacks and receives 2000 surgical pathology specimens yearly. Seven hundred and twenty-two benign breast specimens were analyzed over 5 years from Ist January 2000 to 31 December 2004, out of 1050 breast samples received. Of 1050 breast specimens received, 722 (68.8%) were benign. Fibroadenoma was the most common lesion with 318 cases (44%), occurring at a mean age of 16-32 years. Next were fibrocystic changes with 165 cases (22.9%) at a mean age of 23-45 years. Normal breast in the axillary tail region was seen in 32 cases (4.4%), represented as no pathology, with a mean presentation age of 20-46 years. Low grade Phyllodes tumor had 28 cases (3.9%), presenting at an average mean age of 17-32 years. Lactating adenoma had 19 (2.6%) cases. Other lesions made up less than 3% each. Benign breast lesions peaked at the 20-24 age range and then declined. Most were females. Benign breast lesions occur more frequently than malignant breast lesions with a ratio of 2.3:1 and were presented 20 years earlier than their malignant counterparts. Fibroadenoma was the most common benign lesions followed by fibrocystic disease, similar to the findings in Western Nigeria. In Northern Nigeria, fibrocystic breast disease was more common. (author)

  11. 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.

  12. Diagnostik og behandling af benigne levertumorer

    DEFF Research Database (Denmark)

    Eriksen, Peter Lykke; Schultz, Nicolai Aagaard; Larsen, Lars P.S.

    2016-01-01

    Due to the expanding use of diagnostic imaging, an increasing number of liver tumours are discovered. Benign tumours are very common; they rarely cause symptoms and often they do not require any treatment. However, because of differences in the natural history including risk of complications...... and malignant transformation exact diagnosis is important. Dedicated radiological examinations serve as important diagnostic tools reducing the need for biopsy. In this review we provide an update on the diagnosis and treatment of benign liver tumours adding to existing recommendations on hepatocellular...

  13. Benign Cystic Mesothelioma Misdiagnosed as Peritoneal Carcinomatosis

    Directory of Open Access Journals (Sweden)

    Hyun Deok Shin

    2016-04-01

    Full Text Available Benign cystic mesothelioma (BCM is a rare benign disease that forms multicystic masses in the abdomen, pelvis, and retroperitoneum. It occurs predominantly in young to middle-aged women. The majority of cases were associated with a history of abdominal or pelvic operation, a history of endometriosis, and pelvic inflammatory disease. We present a unique case of BCM which is different to the previous cases. The patient was a 52-year-old man showing features of peritoneal carcinomatosis accompanied by ascites on abdominal computed tomography scans. We herein report a case of BCM misdiagnosed with peritoneal carcinomatosis.

  14. Plain Language Summary: Benign Paroxysmal Positional Vertigo.

    Science.gov (United States)

    Bhattacharyya, Neil; Hollingsworth, Deena B; Mahoney, Kathryn; O'Connor, Sarah

    2017-03-01

    This plain language summary serves as an overview in explaining benign paroxysmal positional vertigo, abbreviated BPPV. This summary applies to patients ≥18 years old with a suspected or potential diagnosis of BPPV and is based on the 2017 "Clinical Practice Guideline: Benign Paroxysmal Positional Vertigo (Update)." The evidence-based guideline includes research to support more effective diagnosis and treatment of BPPV. The guideline was developed as a quality improvement opportunity for managing BPPV by creating clear recommendations to use in medical practice.

  15. Benign Fibröz Histiositoma

    OpenAIRE

    ÖĞÜTCEN TOLLER, Melahat; ÖZKAN, Nilüfer; YILDIZ, Levent

    2015-01-01

    Benign fibröz histiositoma (BFH), ağız kavitesinde nadir görülen, klinik ve histopatolojik olarak teşhiste karışıklığa yol açan bir tümördür. Bu makalede, sağ mandibular bukkal bölgede görülen bir benign fibröz histiositoma vakası sunularak, klinik ve histopatolojik özellikleri tartışıldı.

  16. Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

    International Nuclear Information System (INIS)

    Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Economos, C.; Sato, K.; Kinoshita, M.

    1994-01-01

    The effect of initial mixture temperature on the experimentally measured detonation cell size for hydrogen-air-steam mixtures at 0.1 MPa has been investigated. Experiments were carried out in a 10-cm-inner-diameter, 6.1-m-long heated detonation tube with a maximum operating temperature of 700 K and spatial temperature uniformity of ± 14 K. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air initial gas mixture temperature, in the range 300--650 K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at ay given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm-inside-diameter test vessel, based upon the onset of single-head spin, decreased from 15% hydrogen at 300 K down to about 9% hydrogen at 650 K. The experimental detonation cell size data were correlated suing a Zel'dovich-von Neumann-Doering (ZND) model for the detonation using detailed chemical-kinetic reaction mechanisms. The proportionality constants used to scale the reaction zone length calculations from the ZND model varied from 3o to 51 for the hydrogen-air cell size data at 650 and 300 K, respectively

  17. Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Economos, C.; Sato, K.; Kinoshita, M. (Brookhaven National Lab., Upton, NY (United States). Safety and Risk Evaluation Division)

    1994-11-01

    The effect of initial mixture temperature on the experimentally measured detonation cell size for hydrogen-air-steam mixtures at 0.1 MPa has been investigated. Experiments were carried out in a 10-cm-inner-diameter, 6.1-m-long heated detonation tube with a maximum operating temperature of 700 K and spatial temperature uniformity of [+-] 14 K. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air initial gas mixture temperature, in the range 300--650 K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at ay given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm-inside-diameter test vessel, based upon the onset of single-head spin, decreased from 15% hydrogen at 300 K down to about 9% hydrogen at 650 K. The experimental detonation cell size data were correlated suing a Zel'dovich-von Neumann-Doering (ZND) model for the detonation using detailed chemical-kinetic reaction mechanisms. The proportionality constants used to scale the reaction zone length calculations from the ZND model varied from 3o to 51 for the hydrogen-air cell size data at 650 and 300 K, respectively.

  18. Asymptotic theory of evolution and failure of self-sustained detonations

    Science.gov (United States)

    Kasimov, Aslan R.; Stewart, D. Scott

    2005-02-01

    Based on a general theory of detonation waves with an embedded sonic locus that we have previously developed, we carry out asymptotic analysis of weakly curved slowly varying detonation waves and show that the theory predicts the phenomenon of detonation ignition and failure. The analysis is not restricted to near Chapman-Jouguet detonation speeds and is capable of predicting quasi-steady, normal detonation shock speed versus curvature (D-κ) curves with multiple turning points. An evolution equation that retains the shock acceleration, skew2dot{D}, namely a skew2dot{D}-D-κ relation is rationally derived which describes the dynamics of pre-existing detonation waves. The solutions of the equation for spherical detonation are shown to reproduce the ignition/failure phenomenon observed in both numerical simulations of blast wave initiation and in experiments. A single-step chemical reaction described by one progress variable is employed, but the kinetics is sufficiently general and is not restricted to Arrhenius form, although most specific calculations are performed for Arrhenius kinetics. As an example, we calculate critical energies of direct initiation for hydrogen-oxygen mixtures and find close agreement with available experimental data.

  19. 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.

  20. Equation of State of Detonation Products for TNT by Aquarium Technique

    Science.gov (United States)

    Han, Yong

    2017-06-01

    During explosive detonation, the detonation pressure (P) and temperature (T) will decay quickly with the expansion of detonation products, and the damage effect is determined by the thermodynamic state of detonation products under high pressure. The traditional and important method for calibrating the parameters of thermodynamic state is cylinder test, but the results showed that when the cylinder expanded to a certain distance, the cylinder wall would break up and the detonation products would jet out, which would affect the accuracy of the calibration parameters of thermodynamic state. In this paper, the aquarium technique was used to study the detonation product thermodynamic state of TNT explosive, obtaining the shock wave track under the water and the trace of the interface between water and detonation products in the specific position with the high speed rotating mirror camera. By thermodynamic calculation program BKW and VHL, the parameters of equation of state were obtained. Using the parameters and the dynamic software LS-DYNA, the underwater explosion of TNT was simulated. Comparison with experimental results shows that the thermodynamic state parameters which is calculated by VHL is more accurate than that of BKW. It is concluded that the aquarium test is a more effective method to calibrate the thermodynamic state than cylinder test.

  1. Non-classical detonation regimes of the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene

    Science.gov (United States)

    Mochalova, Valentina; Utkin, Alexander

    2017-06-01

    The experimental study of the liquid explosive tetranitromethane and its mixtures with not detonating liquids (methanol and nitrobenzene) is presented in this work. By the using of a laser interferometer VISAR the stability of detonation waves in that mixtures, depending on the diluent concentration, was investigated. It is shown that the detonation front of these mixtures is stable up to 40% of diluent. Also the dependence of the detonation velocity of tetranitromethane/diluent on the diluent concentration and the limit concentration of the diluent, above which the detonation of the mixture was impossible, were found for each mixture. The compounds of the mixtures, in the reaction zone of which the distribution of parameters didn't correspond to the classical detonation theory, were found. An increase of the pressure and particle velocity behind a shock jump in the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene and the possibility of the existence of a steady-state detonation wave without a Von Neumann spike are interpreted within the framework of models that take into account the possibility of chemical reactions directly in the shock wave front. This work was supported by Russian Foundation for Basic Research (project 15-03-07830).

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

    Science.gov (United States)

    Liu, Q.; Li, S.; Huang, J.; Zhang, Y.

    2017-07-01

    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 have been found 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Uma; Chang, Philip, E-mail: umagarg@uwm.edu, E-mail: chang65@uwm.edu [Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, WI 53211 (United States)

    2017-02-20

    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. Numerical modelling of underwater detonation of non-ideal condensed-phase explosives

    Science.gov (United States)

    Schoch, Stefan; Nikiforakis, Nikolaos

    2015-01-01

    The interest in underwater detonation tests originated from the military, since the expansion and subsequent collapse of the explosive bubble can cause considerable damage to surrounding structures or vessels. In military applications, the explosive is typically represented as a pre-burned material under high pressure, a reasonable assumption due to the short reaction zone lengths, and complete detonation of the unreacted explosive. Hence, numerical simulations of underwater detonation tests have been primarily concerned with the prediction of target loading and the damage incurred rather than the accurate modelling of the underwater detonation process. The mining industry in contrast has adopted the underwater detonation test as a means to experimentally characterise the energy output of their highly non-ideal explosives depending on explosive type and charge configuration. This characterisation requires a good understanding of how the charge shape, pond topography, charge depth, and additional charge confinement affect the energy release, some of which can be successfully quantified with the support of accurate numerical simulations. In this work, we propose a numerical framework which is able to capture the non-ideal explosive behaviour and in addition is capable of capturing both length scales: the reaction zone and the pond domain. The length scale problem is overcome with adaptive mesh refinement, which, along with the explosive model, is validated against experimental data of various TNT underwater detonations. The variety of detonation and bubble behaviour observed in non-ideal detonations is demonstrated in a parameter study over the reactivity of TNT. A representative underwater mining test containing an ammonium-nitrate fuel-oil ratestick charge is carried out to demonstrate that the presented method can be readily applied alongside experimental underwater detonation tests.

  5. Linear stability analysis of detonations via numerical computation and dynamic mode decomposition

    KAUST Repository

    Kabanov, Dmitry

    2018-03-20

    We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.

  6. On investigation of optical and spin properties of NV centers in aggregates of detonation nanodiamonds

    Science.gov (United States)

    Bolshedvorskii, S. V.; Vorobyov, V. V.; Soshenko, V. V.; Zeleneev, A.; Sorokin, V. N.; Smolyaninov, A. N.; Akimov, A. V.

    2018-02-01

    Quickly developing application of nitrogen-vacancy color centers in diamond sets demands on cheap and high optical and spin properties nanodiamonds. Among other types, detonation nanodiamonds are easiest for production but often show no NV color centers inside. In this work we show, that aggregates of detonation nanodiamonds could be as good, or even better in terms of brightness and spin properties, than more expensive single crystal nanodiamonds. This way aggregates of detonation nanodiamonds could efficiently serve as cheap and bright source of single photon radiation or sensitive element of biocompatible sensor.

  7. Linear stability analysis of detonations via numerical computation and dynamic mode decomposition

    KAUST Repository

    Kabanov, Dmitry I.

    2017-12-08

    We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.

  8. Adaptive mesh simulations of astrophysical detonations using the ASCI flash code

    Science.gov (United States)

    Fryxell, B.; Calder, A. C.; Dursi, L. J.; Lamb, D. Q.; MacNeice, P.; Olson, K.; Ricker, P.; Rosner, R.; Timmes, F. X.; Truran, J. W.; Tufo, H. M.; Zingale, M.

    2001-08-01

    The Flash code was developed at the University of Chicago as part of the Department of Energy's Accelerated Strategic Computing Initiative (ASCI). The code was designed specifically to simulate thermonuclear flashes in compact stars (white dwarfs and neutron stars). This paper will give a brief introduction to the astrophysics problems we wish to address, followed by a description of the current version of the Flash code. Finally, we discuss two simulations of astrophysical detonations that we have carried out with the code. The first is of a helium detonation in an X-ray burst. The other simulation models a carbon detonation in a Type Ia supernova explosion. .

  9. The ABC of benign breast disease

    African Journals Online (AJOL)

    reassurance of its benign nature may be all that is necessary, along with firm brassiere support and, possibly, the use of mild analgesics. Underlying precipitating factors, such as marijuana or other drug use, should be eliminated. Some patients benefit from avoidance of methylxanthines (i.e. caffeine in cola, tea, and coffee), ...

  10. 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...

  11. Imaging features of benign adrenal cysts

    International Nuclear Information System (INIS)

    Sanal, Hatice Tuba; Kocaoglu, Murat; Yildirim, Duzgun; Bulakbasi, Nail; Guvenc, Inanc; Tayfun, Cem; Ucoz, Taner

    2006-01-01

    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

  12. Ureteritis cystica: A rare benign lesion

    African Journals Online (AJOL)

    F. Ibrahim

    www.sciencedirect.com. Case report. Ureteritis cystica: A rare benign lesion. F. Ibrahim. Department of Surgery, Alzaytona Specialized Hospital, Khartoum, Sudan. Received 16 January 2014; received in revised form 28 March 2014; accepted 28 March 2014. KEYWORDS. Ureter;. Ureteritis Cystica;. Ureteroscopy;. Sudan.

  13. Benign paroxysmal positional vertigo and its variants.

    Science.gov (United States)

    Nuti, D; Masini, M; Mandalà, M

    2016-01-01

    Benign paroxysmal positional vertigo is a common labyrinthine disorder caused by a mechanic stimulation of the vestibular receptors within the semicircular canals. It is characterized by positional vertigo and positional nystagmus, both provoked by changes in the position of the head with respect to gravity. The social impact of the disease and its direct and indirect costs to healthcare systems are significant owing to impairment of daily activities and increased risk of falls. The first description of a patient with benign paroxysmal positional vertigo is from Robert Bárány in 1921, but the features of the syndrome and the diagnostic maneuver were well described by Dix and Hallpike in 1952. Since then, the gradually increasing interest of otolaryngologists and neurologists has led to a progressive advance in the knowledge of this labyrinthine disorder with regard to its epidemiologic, pathophysiologic, clinical, and therapeutic aspects. Despite the often effective diagnosis and treatment of most cases of benign paroxysmal positional vertigo, the physiopathologic explanations of the disease are mainly speculative. In this chapter, we describe the epidemiologic, pathophysiologic, clinical, and therapeutic aspects of benign paroxysmal positional vertigo. © 2016 Elsevier B.V. All rights reserved.

  14. Transurethral microwave thermotherapy in benign prostatic hyperplasia

    NARCIS (Netherlands)

    Minnee, P.; Debruyne, F. M.; de la Rosette, J. J.

    2000-01-01

    This article reviews the available literature and data on high-energy transurethral microwave therapy (TUMT) in the treatment of benign prostatic hyperplasia (BPH) causing lower urinary tract symptoms (LUTS). TUMT is a safe, durable, (1-hour) procedure, without the need for anesthesia. Emphasis is

  15. Benign osteoblastoma of the temporal bone: MRI

    International Nuclear Information System (INIS)

    Tsuchida, T.; Nagao, S.

    1995-01-01

    We investigated a 27-year-old woman with a retro-auricular tumour. MRI revealed a signal void on T1- and T2-weighted images, and irregular enhancement with gadolinium-DTPA. The underlying dura mater also enhanced. The tumour was resected completely, and histological examination showed a benign osteoblastoma. (orig.)

  16. Benign osteoblastoma of the temporal bone: MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, T. [Dept. of Neurological Surgery, Kagawa Medical School, Kagawa (Japan); Nagao, S. [Dept. of Neurological Surgery, Kagawa Medical School, Kagawa (Japan)

    1995-05-01

    We investigated a 27-year-old woman with a retro-auricular tumour. MRI revealed a signal void on T1- and T2-weighted images, and irregular enhancement with gadolinium-DTPA. The underlying dura mater also enhanced. The tumour was resected completely, and histological examination showed a benign osteoblastoma. (orig.)

  17. Case Report: Benign Multicystic Peritoneal Mesothelioma

    Directory of Open Access Journals (Sweden)

    Nurettin Boran

    2011-08-01

    In conclusion BPMP is a rare benign cystic tumor which can be easily misdiagnosed as an ovarian cancer preoperatively. Intraoperative findings and appearence of the mass may mimic malignancy. For that reason frozen section examination will prevent overtreatment.

  18. Abdominal Hysterectomy for Benign Gynaecological Conditions in ...

    African Journals Online (AJOL)

    There was no case-fatality. The procedure is very safe in our centre; however there is need for a re-appraisal of our pre-operative evaluation and antibiotic prophylaxis in order to reduce postoperative anaemia and pyrexia associated with this procedure. Key words: Hysterectomy, Abdominal, Gynaecological, Benign.

  19. Benign Recurrent Sixth Cranial Nerve Palsies

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2009-06-01

    Full Text Available A retrospective chart review of a cohort of 253 pediatric patients with sixth nerve palsies uncovered 30 cases of benign sixth nerve palsy, of which 9 were recurrent, in a study at University of Pennsylvania School of Medicine, Philadelphia.

  20. PET in Benign Bone Marrow Disorders

    NARCIS (Netherlands)

    van der Bruggen, Wouter; Glaudemans, Andor W. J. M.; Vellenga, Edo; Slart, Riemer H. J. A.

    This review aims to describe the current status of benign bone marrow (BM) imaging using PET. BM imaging is important as the BM is not only involved in poiesis of different vital cell lines and. can be affected by primary BM disorders, but it is also frequently affected by several extramedullary

  1. 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...

  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, 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

  3. Application of Anova to Pulse Detonation Engine Dynamic Performance Measurements

    Science.gov (United States)

    Chander, Subhash; Kumar, Rakesh; Sandhu, Manmohan; Jindal, TK

    2017-10-01

    Application of Anova to Pulse detonation engine dynamic performance measurement resulted in quantifying engine functionality during various operations. After evaluating the performance, techniques of improving it, were applied in multiple areas of relevant interest. This produced encouraging results and helped in upscaling efforts in a significant manner. The current paper deals in the details of anova implementation and systematic identification of key areas of improvements. The improvements were carried out after careful selection of plans in the engine, ground rig and instrumentation setup etc. It also yielded better reproducibility of performance and optimization of main subsystems of PDE. Further, this will also contribute to reduce the development cycle and trial complexity also, if researchers continue to extract concern areas to be addressed.

  4. Formation mechanisms and characteristics of transition patterns in oblique detonations

    Science.gov (United States)

    Miao, Shikun; Zhou, Jin; Liu, Shijie; Cai, Xiaodong

    2018-01-01

    The transition structures of wedge-induced oblique detonation waves (ODWs) in high-enthalpy supersonic combustible mixtures are studied with two-dimensional reactive Euler simulations based on the open-source program AMROC (Adaptive Mesh Refinement in Object-oriented C++). The formation mechanisms of different transition patterns are investigated through theoretical analysis and numerical simulations. Results show that transition patterns of ODWs depend on the pressure ratio Pd/Ps, (Pd, Ps are the pressure behind the ODW and the pressure behind the induced shock, respectively). When Pd/Ps > 1.3, an abrupt transition occurs, while when Pd/Ps 1.02Φ∗ (Φ∗ is the critical velocity ratio calculated with an empirical formula).

  5. Analytical Methods for Detonation Residues of Insensitive Munitions

    Science.gov (United States)

    Walsh, Marianne E.

    2016-01-01

    Analytical methods are described for the analysis of post-detonation residues from insensitive munitions. Standard methods were verified or modified to obtain the mass of residues deposited per round. In addition, a rapid chromatographic separation was developed and used to measure the mass of NTO (3-nitro-1,2,4-triazol-5-one), NQ (nitroguanidine) and DNAN (2,4-dinitroanisole). The HILIC (hydrophilic-interaction chromatography) separation described here uses a trifunctionally-bonded amide phase to retain the polar analytes. The eluent is 75/25 v/v acetonitrile/water acidified with acetic acid, which is also suitable for LC/MS applications. Analytical runtime was three minutes. Solid phase extraction and LC/MS conditions are also described.

  6. Efficient numerical simulation of the deflagration-to-detonation transition

    International Nuclear Information System (INIS)

    Ettner, Florian Anton

    2013-01-01

    In order to improve safety analyses of nuclear power plants, it is necessary to investigate if hydrogen-air mixtures (created in severe accidents) burn in a deflagrative manner or whether a deflagration-to-detonation transition (DDT) occurs. In this work a CFD solver has been developed for the simulation of a complete combustion process including DDT. The density-based solver incorporates a deflagration model and an auto-ignition model which are coupled via a progress variable. The application to both homogeneous and inhomogeneous mixtures shows very good agreement with experiments. Depending on the boundary conditions the presence of a hydrogen concentration gradient can either increase or decrease the probability of DDT when compared to a homogeneous mixture. Under certain circumstances extremely high pressure loads occur even in areas of low hydrogen content. This should be taken into consideration in future safety analyses.

  7. 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.

  8. Tidal double detonation: a new mechanism for the thermonuclear explosion of a white dwarf induced by a tidal disruption event

    Science.gov (United States)

    Tanikawa, Ataru

    2018-03-01

    We suggest tidal double detonation as a new mechanism for the thermonuclear explosion of a white dwarf (WD) induced by a tidal disruption event (TDE). Tidal detonation is also a WD explosion induced by a TDE. In this case, helium (He) and carbon-oxygen (CO) detonation waves incinerate He WDs and CO WDs, respectively. On the other hand, for tidal double detonation, He detonation is first excited in the He shell of a CO WD, which then drives CO detonation in the CO core. We name this mechanism after the double detonation scenario in the context of type Ia supernovae. In this paper, by performing numerical simulations for CO WDs of mass 0.60 M⊙ with and without a He shell, we show that tidal double detonation occurs in the shallower encounter of a CO WD with an intermediate-mass black hole (IMBH) compared to simple tidal detonation. We expect tidal double detonation will increase the possibility of the occurrence of WD TDEs, which can help us to understand IMBHs.

  9. 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.

  10. Research on laser detonation pulse circuit with low-power based on super capacitor

    Science.gov (United States)

    Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

    2018-03-01

    According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

  11. 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.

  12. Novel Experimental, Theoretical, and Calculational Approaches to Understanding the Detonation of Explosives

    National Research Council Canada - National Science Library

    Eckhardt, Craig

    2003-01-01

    Report of results of research on the initial stage of detonation is made. Experimental results involve location of a heretofore undetected intramolecular mode in RDX and confirmation of prior findings on the Raman scattering of HMX...

  13. Simulating the blast wave from detonation of a charge using a balloon of compressed air

    Science.gov (United States)

    Blanc, L.; Santana Herrera, S.; Hanus, J. L.

    2017-11-01

    This paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass.

  14. 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.

  15. A simple approach for determining detonation velocity of high explosive at any loading density.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2005-05-20

    A simple empirical relationship is introduced between detonation velocity at any loading density and chemical composition of high explosive as well as its gas phase heat of formation, which is calculated by group additivity rules. The present work may be applied to any explosive that contains the elements of carbon, hydrogen, nitrogen and oxygen with no difficulties. The new correlation can easily be applied for determining detonation velocity of explosives with loading densities less than 1g/cm3 as well as greater than 1g/cm3. Calculated detonation velocities by this procedure for both pure and explosive formulations show good agreement with respect to measured detonation velocity over a wide range of loading density.

  16. The Passage of a Detonation Wave Across the Interface between Two Explosives

    National Research Council Canada - National Science Library

    Pike, H. H; Weir, R. E

    1950-01-01

    .... The case of most interest is that in which the first explosive overdrives the second, the pressure and detonation velocity in the second explosive having values higher than normal and the Chapman...

  17. Small-scale Detonation Velocity Measurement of Select CL-20 Cocrystals

    Science.gov (United States)

    Vuppuluri, Vasant; Gunduz, I. Emre; Son, Steven F.

    2017-06-01

    The challenge of developing novel energetic materials makes cocrystallization using existing energetic molecules useful. Cocrystallization of CL-20 with other high explosives such as HMX has been demonstrated previously to yield novel energetic materials and may have favorable detonation performance. However, detonation performance characterization of these cocrystals is challenging due to limited availability of material. Also, the contribution of bonding energy between coformers contained within the cocrystal is not well-understood. We present the comparison of steady detonation velocities of CL-20 cocrystals to their corresponding physical mixtures using microwave interferometry. With less than 1.5 g of the cocrystal material contained within 6.52 mm diameter charges, shot-to-shot variation in detonation velocity of only about 100 m/s are achievable with this technique. This variation is adequate to resolve relatively small differences between physical mixed explosive molecules and cocrystals.

  18. 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.

  19. Carbon Condensation during High Explosive Detonation with Time Resolved Small Angle X-ray Scattering

    Science.gov (United States)

    Hammons, Joshua; Bagge-Hansen, Michael; Nielsen, Michael; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; Fried, Larry; May, Chadd; Sinclair, Nicholas; Jensen, Brian; Gustavsen, Rick; Dattelbaum, Dana; Watkins, Erik; Firestone, Millicent; Ilavsky, Jan; van Buuren, Tony; Willey, Trevor; Lawrence Livermore National Lab Collaboration; Los Alamos National Laboratory Collaboration; Washington State University/Advanced Photon Source Team

    Carbon condensation during high-energy detonations occurs under extreme conditions and on very short time scales. Understanding and manipulating soot formation, particularly detonation nanodiamond, has attracted the attention of military, academic and industrial research. An in-situ characterization of these nanoscale phases, during detonation, is highly sought after and presents a formidable challenge even with today's instruments. Using the high flux available with synchrotron X-rays, pink beam small angle X-ray scattering is able to observe the carbon phases during detonation. This experimental approach, though powerful, requires careful consideration and support from other techniques, such as post-mortem TEM, EELS and USAXS. We present a comparative survey of carbon condensation from different CHNO high explosives. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  1. 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...

  2. Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-12

    For high explosive (HE) simulations, inaccuracies of a per cent or two in the detonation wave speed can result from not suficiently resolving the reaction zone width or from small inaccuracies in calibrating the products equation of state (EOS) or from variation of HE lots. More accurate detonation speeds can be obtained by ne tuning the equation of state to compensate. Here we show that two simple EOS transformations can be used to adjust the CJ detonation speed by a couple of per cent with minimal effect on the CJ release isentrope. The two transformations are (1) a shift in the energy origin and (2) a linear scaling of the speci c volume. The effectiveness of the transformations is demonstrated with simulations of the cylinder test for PBX 9502 starting with a products EOS for which the CJ detonation speed is 1 per cent too low.

  3. Design methodology for understanding the sympathetic detonation characteristics of insensitive high explosives

    OpenAIRE

    Raghavan, Dinesh.

    2005-01-01

    The understanding of sympathetic detonation of energetic materials is important from the stand point of safety, shelf life, storage requirements and handling. The objective of this thesis is to introduce a methodology to assess performance and sensitivity levels of insensitive munitions to sympathetic detonations. AUTODYN code was utilized to validate the shock sensitivity results for Composition B explosives. Upon code validation, simulations were conducted to evaluate small scale sympat...

  4. Shock-to-detonation transition of RDX and NTO based composite high explosives: experiments and modeling

    Science.gov (United States)

    Baudin, Gerard; Roudot, Marie; Genetier, Marc

    2013-06-01

    Composite HMX and NTO based high explosives (HE) are widely used in ammunitions. Designing modern warheads needs robust and reliable models to compute shock ignition and detonation propagation inside HE. Comparing to a pressed HE, a composite HE is not porous and the hot-spots are mainly located at the grain - binder interface leading to a different behavior during shock-to-detonation transition. An investigation of how shock-to-detonation transition occurs inside composite HE containing RDX and NTO is proposed in this lecture. Two composite HE have been studied. The first one is HMX - HTPB 82:18. The second one is HMX - NTO - HTPB 12:72:16. These HE have been submitted to plane sustained shock waves at different pressure levels using a laboratory powder gun. Pressure signals are measured using manganin gauges inserted at several distances inside HE. The corresponding run-distances to detonation are determined using wedge test experiments where the plate impact is performed using a powder gun. Both HE exhibit a single detonation buildup curve in the distance - time diagram of shock-to-detonation transition. This feature seems a common shock-to-detonation behavior for composite HE without porosity. This behavior is also confirmed for a RDX - HTPB 85:15 based composite HE. Such a behavior is exploited to determine the heterogeneous reaction rate versus the shock pressure using a method based on the Cauchy-Riemann problem inversion. The reaction rate laws obtained allow to compute both run-distance to detonation and pressure signals.

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

    OpenAIRE

    Xi-qiao Huang; Moqi Li; Yuan-yuan Yuan; Yue-fei Xiong; Longxi Zheng

    2015-01-01

    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 ex...

  6. Thermodynamic Cycle and CFD Analyses for Hydrogen Fueled Air-breathing Pulse Detonation Engines

    Science.gov (United States)

    Povinelli, Louis A.; Yungster, Shaye

    2002-01-01

    This paper presents the results of a thermodynamic cycle analysis of a pulse detonation engine (PDE) using a hydrogen-air mixture at static conditions. The cycle performance results, namely the specific thrust, fuel consumption and impulse are compared to a single cycle CFD analysis for a detonation tube which considers finite rate chemistry. The differences in the impulse values were indicative of the additional performance potential attainable in a PDE.

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

    Science.gov (United States)

    2016-05-16

    revised form 26 February 2015 Accepted 26 February 2015 Available online 17 March 2015 Keywords: Flame propagation Non-equilibrium plasma Plasma...and thus has a fas- ter energy deposition than these other plasma discharge types [3,8]. While all atmospheric pressure discharges must be initialized... flame and undergo DDT. Third is detonation wave propagation, which produces a rapid pressure rise, accelerating the burned gas through the detonation

  8. Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation

    Science.gov (United States)

    2016-04-30

    renewed interests on rotating detonation engine (RDE) concept driven by potential benefits on thermodynamic efficiency of detonation cycle over...implies shocks reflected off of irregular annulus features are unlikely to serve as a significant thermodynamic cycle loss mechanism. 3. In cases...known. The subscript i stands for the inert bounding gas, and the subscript e for the explosive mixture. Since Pe3 = Pi2 , there are now only three

  9. Determination of favorable conditions of detonation in liquid and solid substance mixtures

    International Nuclear Information System (INIS)

    Aubeau, Raymond; Carles, Maurice; Cochet Muchy, Bernard; Ducouret, Andre

    1976-03-01

    Theoretical methods or testing techniques may be employed to provide for possible detonations of chemical substances capable of interreactions. The theoretical methods are based upon the determination of the specific energy of possible mixtures and the system geometry. But the testing techniques are the only ones to insure whether a given mixture may detonate, deflagrate or to be inert. Different possible examples are given [fr

  10. Finite element analysis of Polymer reinforced CRC columns under close-in detonation

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin

    2007-01-01

    load. Experimental and numerical results of two PCRC columns subjected to close-in detonation are presented in this paper. Additionally, a LS-DYNA material model suitable for predicting the response of Polymer reinforced Compact Reinforced Concrete improved for close-in detonation and a description...... of the LS-DYNA multi-material Eulerian method for modeling the blast event is also presented in this paper....

  11. 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.

  12. 1 Massive upper gastrointestinal bleeding and diffuse benign gastric ...

    African Journals Online (AJOL)

    Abstract: Benign gastric inflammatory hyperplasic polyps are benign lesions that rarely occur in young age. We report a case of diffuse benign gastric inflammatory hyperplastic polyps in a 19 year old male patient who presented with cough, nausea, and haematemesis. In the presented case symptoms such as nausea and.

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

    International Nuclear Information System (INIS)

    Bae, So Young; Yi, Boem Ha; Lee, Hae Kyung; Park, Seong Jin; Cho, Gyu Seok; Kwak, Jeong Ja

    2010-01-01

    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

  14. 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.

  15. Comparative performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs

    Directory of Open Access Journals (Sweden)

    Sudip Bhattrai

    2013-09-01

    Full Text Available Combined-cycle pulse detonation engines are promising contenders for hypersonic propulsion systems. In the present study, design and propulsive performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs is presented. Analysis is done with respect to Mach number at two consecutive modes of operation: (1 Combined-cycle PDTE using a pulse detonation afterburner mode (PDA-mode and (2 combined-cycle PDTE in pulse detonation ramjet engine mode (PDRE-mode. The performance of combined-cycle PDTEs is compared with baseline afterburning turbofan and ramjet engines. The comparison of afterburning modes is done for Mach numbers from 0 to 3 at 15.24 km altitude conditions, while that of pulse detonation ramjet engine (PDRE is done for Mach 1.5 to Mach 6 at 18.3 km altitude conditions. The analysis shows that the propulsive performance of a turbine engine can be greatly improved by replacing the conventional afterburner with a pulse detonation afterburner (PDA. The PDRE also outperforms its ramjet counterpart at all flight conditions considered herein. The gains obtained are outstanding for both the combined-cycle PDTE modes compared to baseline turbofan and ramjet engines.

  16. Small gap test of electric detonators. Denki raikan no kogata gap shiken

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, A.; Matsuzawa, T.; Yoshida, N. (Nippon Kayaku Co. Ltd., Tokyo (Japan)); Wada, Y.; Yahashi, H.; Tamura, S.; Yoshida, T. (The Univ. of Tokyo, Tokyo (Japan). Faculty of Engineering)

    1990-06-30

    An electric detonator is an important ammunition for initiating explosive. Since it has a high dangerousness in its handling, various measures for the transportation and the storage are being studied. In this paper, small gap test was taken as a preliminary test to assess safety package of electric detonators. Meanwhile, to examine the effect of cushioning materials, five kinds of materials such as styrene foam and river sand were used as specimen. Shock sensitivity of the detonator depended on a position which was added a shock from the detonator. Positions where contain more sensitive explosives showed more sensitivity. River sand and phenol foam absorbed shock wave from detonators more effectively than other materials which were tested, and were thought to be useful as a buffer for preventing the sympathetic detonation. In the underwater small gap test, different gap materials, i.e. cards or sticks, gave different results, though the total gap lengths were same. Critical gap lengths were also different in air and underwater. These results are the subjects to be studied in future. 5 refs., 3 figs., 2 tabs.

  17. 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.

  18. The Microstructure Characteristics of RDX and their Effect on the Detonation Velocity

    Science.gov (United States)

    Bellitto, Victor; Melnik, Mikhail; Sherlock, Mary; Chang, Joseph; O'Connor, John; Mackey, Joseph; Nswc-Iheodtd Collaboration

    2017-06-01

    Numerous methods exist for the theoretical calculation of detonation parameters of explosives. However, thermodynamic-hydrodynamic based theoretical codes seldom take into account particle size as a basis for the computational analysis as they primarily focus on the equation of state of the detonation products, heat of formation and density of the explosive composition. This study utilized regression analysis to model the relationship between the microstructure characteristics and detonation velocity of a heterogeneous high-explosive composition containing RDX. The principal characteristics examined were the average particle size of RDX, impurity within the RDX particles, method of RDX manufacture, and compositional density. Statistical analysis demonstrated the relevancy of the microstructure influence on the detonation velocity of the developed experimental compositions of 73 wt. % solids and 27 wt. % polyurethane binder. The developed statistical model accurately predicts the detonation velocity of the heterogeneous composition used in our experiments. The model underscores the significance of the relationship between the average particle size and detonation velocity. The importance of using statistical models for selecting characteristics that result in optimum explosive performance are addressed.

  19. 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.

  20. Coupling Detonation Shock Dynamics in a Consistent Manner to Equations of State

    Science.gov (United States)

    Belfield, William

    2017-06-01

    In hydrocode simulations, detonating high explosives (HE) are often modelled using programmed burn. Each HE cell is assigned a ``burn time'' at which it should begin to behave as HE products in the subsequent simulation. Traditionally, these burn times were calculated using a Huygens construction to propagate the detonation wave at a constant speed corresponding to the planar Chapman-Jouguet (CJ) velocity. The Detonation Shock Dynamics (DSD) model improves upon this approach by treating the local detonation velocity as a function of wave curvature, reflecting that the detonation speed is not constant in reality. However, without alterations being made, this variable detonation velocity is inconsistent with the CJ velocity associated with the HE products equation of state (EOS). Previous work has shown that the inconsistency can be resolved by modifying the HE product EOS, but this treatment is empirical in nature and has only been applied to the JWL EOS. This work investigates different methods to resolve the inconsistency that are applicable both to JWL and to tabular HE product EOS, and their impact on hydrocode simulations.

  1. Numerical simulation of double front detonations in a non-ideal explosive with varying aluminum concentration

    Science.gov (United States)

    Kim, Wuhyun; Gwak, Min-Cheol; Yoh, Jack; Seoul National University Team

    2017-06-01

    The performance characteristics of aluminized HMX are considered by varying the aluminum (Al) concentration in a hybrid non-ideal detonation model. Two cardinal observations are reported: a decrease in detonation velocity with an increase in Al concentration and a double front detonation (DFD) feature when aerobic Al reaction occurs behind the front. While experimental studies have been reported on the effect of Al concentration on both gas-phase and solid-phase detonations, the numerical investigations were limited to only gas-phase detonation for the varying Al concentration. In the current study, a two-phase model is utilized for understanding the volumetric effects of Al concentration in the condensed phase detonations. A series of unconfined and confined rate sticks are considered for characterizing the performance of aluminized HMX with a maximum Al concentration of 50%. The simulated results are compared with the experimental data for 5%-25% concentrations, and the formation of DFD structure under varying Al concentration (0%-50%) in HMX is investigated.

  2. Stable detonation characteristics of premixed C2H4/O2 gas in narrow gaps

    Science.gov (United States)

    Zhu, Yuejin; Pan, Zhenhua; Zhang, Penggang; Pan, Jianfeng

    2017-09-01

    The detonation initiation and propagation characteristics of premixed gas in a confined channel are greatly influenced by some external factors, such as the channel size and the initial pressure. The influences of different gap height and initial pressure of stoichiometric C2H4/O2 combustible premixed gas on the detonation characteristics were investigated using the self-made narrow gaps. The flame propagation processes were captured by the high-speed photography and the detonation trajectories were recorded by the soot-foil technology. The results show that the gap height is found to be proportional to P0^{ - 1.493} of the dividing lines, which are used to distinguish the three different detonation states. The detonation initiation process can be accelerated by either decreasing the gap height or increasing the initial pressure. Furthermore, the detonation velocity deficit is closely related to the gap height and the initial pressure, and the relation can be expressed as dV ∝ H^{ - 0.8} P0^{ - 0.5}.

  3. Analog System of Detonations with Loss and Stability of the Analog System

    Science.gov (United States)

    Sun, Yuanxiang; Wang, Cheng; Group of Computationa Fluid Dynamics Team

    2017-06-01

    Analog system of detonation is a simplified model of the Euler system. Analog system removes unnecessary details of the Euler system and reduces mathematical difficulty Analog system with losses and reaction mechanism that applicable for condensed-phase detonation is studied to examine whether the analog system in this paper is valid Details are as follows: 1. The relationship of detonation velocity vs. loss parameter is analytically solved, and a minimal state-dependence of the reaction rate n required for this relationship to exhibit a critical behavior (i.e., a turning point) is examined The results agree with the limits which derived from Euler system. 2. Normal-mode method is used to study the stability of the analog system. A radiation (closure) condition is derived and applied at the end of the reaction zone. An analysis is performed to investigate whether the ideal, steady-state detonation can keep stable to small perturbations 3. Because analog system with loss can be more unstable than the ideal one. An numerical simulation is used to examine the detonation stability near the loss limits. The results above show that the analog system is basically valid for condensed-phase detonation.

  4. Experimentation and direct numerical simulation of self-similar convergent detonation wave

    Directory of Open Access Journals (Sweden)

    Bozier O.

    2011-01-01

    Full Text Available The propagation of self similar convergent detonation wave in TATB-based explosive composition was studied both experimentally and numerically. The device constists in a 50 mm cylinder of TATB surrounded by an HMX tube. The detonation in HMX overdrives the detonation in TATB which adapts to the propagation velocity with a convergent front at centerline. We measured a curvature of κ = −21.2 m−1 for propagation velocity of 8750 m/s, which extends the knowledge of the (Dn,κ law. A wide ranged EOS/reaction rate model inspired from previous work of Wescott et al. was calibrated to reproduce both the run-to-detonation distance and the newly extended (Dn,κ law for the 1D sligthly curved detonation theory. 2D Direct Numerical Simulations (DNS were made on fine resolved mesh grid for the experimental configuration and for various driver velocities. The simulation reproduces the experimental data both qualitatively (overall detonation structure and quantitatively (κ = −25.4 m−1.

  5. 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.)

  6. The effect of voide size on the detonation pressure of emulsion explosives.

    Science.gov (United States)

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

    2001-06-01

    Ammonium nitrate-based emulsion explosive show non-ideal detonation behavior. Voids included in the emulsion explosives affect the non-idealdetonation behavior. The effects of voide size on the detonation pressure of emulsion explosives were studied experimentally. Detonation pressure was measured for the emulsion explosives sensitized with resin balloons of five different size ranging from 0.05mm to 2.42mm in average diameter, using PVDF pressure sensor. Pressure profile of emulsion explosives containing resin balloon of 0.05mm in average diamater shows von Neumann spike and pressure decay in reaction zone followed by Taylor wave. Pressure profile of emulsion explosive containing larger balloons present gradual pressure rise in detonation front due to front curvature and front perturvation caused by large voids. The comparison between the measured detonation pressure and calculated detonation pressure indicates that the fraction of ammonium nitrate reacted in reaction zone is higher than 80containing resin balloons of 0.05mm in diameter, and as low as 302.42mm in diameter. It was shown that reaction zone length is strongly affected by void size.

  7. Perchlorate contamination from the detonation of insensitive high-explosive rounds.

    Science.gov (United States)

    Walsh, Michael R; Walsh, Marianne E; Ramsey, Charles A; Brochu, Sylvie; Thiboutot, Sonia; Ampleman, Guy

    2013-11-15

    The insensitive high-explosive PAX-21 was the first of its kind fielded in an artillery munition by the United States military. This formulation contains three main components: RDX, dinitroanisole, and ammonium perchlorate (AP). In March 2012, detonation tests were conducted on PAX-21 60mm mortar rounds to determine the energetic residues resulting from high-order and blow-in-place (BIP) detonations. Post-detonation residues were sampled and analyzed for the three main PAX-21 components. Concentrations of RDX and dinitroanisole in the samples were quite low, less than 0.1% of the munitions' original organic explosive filler mass, indicating high order or near high order detonations. However, disproportionately high concentrations of AP occurred in all residues. The residues averaged 15% of the original AP following high-order detonations and 38% of the original AP mass following the BIP operations. There was no correlation between AP residues and the RDX and dinitroanisole. Perchlorate readily leached from the detonation residues, with over 99% contained in the aqueous portion of the samples. Use of these rounds will result in billions of liters of water contaminated above drinking water perchlorate limits. As a result of this research, PAX-21 mortar rounds are currently restricted from use on US training ranges. Published by Elsevier B.V.

  8. SPONTANEOUS INITIATION OF DETONATIONS IN WHITE DWARF ENVIRONMENTS: DETERMINATION OF CRITICAL SIZES

    International Nuclear Information System (INIS)

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

    2009-01-01

    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 12 C/ 16 O 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.

  9. Radiotherapy in benign uterine bleeding disorders

    International Nuclear Information System (INIS)

    Ryberg, M.; Pettersson, F.; Lundell, M.

    1989-01-01

    Radiotherapy was earlier a method of choice for treatment of benign bleeding disorders (metropathia), especially in woman of high surgical risk. During the period 1912 to 1977 933 women with benign bleeding disorders were treated at Radiumhemmet with intracavitary brachytherapy or external irradiation or a combination of both. The result with regard to cure of the uterine bleedings was good (48%). Hormonal withdrawal symptoms after treatment were noted in 45% of the patients. In the long term follow up an increased risk of cardiovascular death was found in women treated before menopause. Malignant tumours occurred in 107 cases versus 90.2 expected. The estimated ovarian dose of ionizing radiation varied from 3.5 Gy to 6.0 Gy for the three standard techniques. Two women gave birth to a healthy child 4 and 5 years after intracavitary radium treatment. The estimated absorbed dose to the ovaries in these two women were 1 Gy and 4 Gy, respectively

  10. 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...... benign thyroid nodule. None of the patients had uptake on a radionuclide scan. Patients underwent one ILP session. A needle was positioned in the thyroid nodule with US guidance, and the laser fiber was placed in the lumen of the needle. Patients were treated for 287-1,200 seconds with an output power...... of 1-3 W. ILP was performed with continuous US guidance and terminated when the echogenic changes were stationary. Thyroid nodule volume and thyroid function were evaluated before and 1, 3, and 6 months after treatment. During the same period, 15 untreated patients (control group) were followed up...

  11. Italian survey on benign paroxysmal positional vertigo

    OpenAIRE

    Messina, A.; Casani, A.P.; Manfrin, M.; Guidetti, G.

    2017-01-01

    SUMMARY Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. BPPV often relapses after the first episode, with a recurrence rate between 15% and 50%. To date both the aetiopathogenetic processes that lead to otoconia detachment and the factors that make BPPV a relapsing disease are still unclear, but recent epidemiological studies have shown a possible association with cardiovascular risk factors. The aim of the present study (Sesto Senso Survey) was to e...

  12. 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.

  13. Percutaneous treatment of benign bile duct strictures

    International Nuclear Information System (INIS)

    Koecher, Martin; Cerna, Marie; Havlik, Roman; Kral, Vladimir; Gryga, Adolf; Duda, Miloslav

    2007-01-01

    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

  14. Recurrent benign adrenal pheochromocytomas associated with hemihypertrophy.

    Science.gov (United States)

    Pikilidou, Maria; Yavropoulou, Maria; Katsounaros, Marios

    2014-01-01

    We report a case of a female with hemihypertrophy, who developed five recurrences of pheochromocytomas until the age of 35. Timely follow-up of the patient's blood pressure assisted in early diagnosis and treatment of recurrent tumors. Recurrent benign pheochromocytomas should raise suspicion of a genetic syndrome.A pheochromocytoma at a young age has a high propensity to recur and strict follow-up is mandatory.

  15. [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.

  16. 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.

  17. Benign Eyelid Lesions: Six Months Study

    Directory of Open Access Journals (Sweden)

    E Abbasi Shavvazi

    2013-04-01

    Full Text Available Introduction: Benign eyelid lesions are classified to infectious, inflammatory and tumoral lesions. The various number of these lesions is due to unique eyelid anatomical structure. Some lesions are simple and do not need any treatment but sometimes patients refer to ophthalmologists due to beauty or problems such as pain, swelling. The aim of our study is to investigate and compare the relative frequency of benign eyelid lesions in Shahid Sadoughi eye clinic as well as the private offices. Methods: This cross sectional six month study was done on 247 patients who referred to Shahid Sadoughi eye clinic and the private offices in 2011. They were examined by direct observation and slit lamp regardless of the cause. The information was gleaned by a questionnaire and the research data was analyzed by SPSS (ver.16. Results: we studied 247 patients including 84(34% male and 163(6% female. The mean age of the patients was 42.7 years. 60.2% of lesions were in upper lid and 39.8% were in lower lid. 51.2% of lesions were in right eye and 48.8% were in left eye. The most common eyelid lesions were papilloma (32.9% nevus (21.9% and chalazion (14.1% respectively. Conclusion: Papilloma, nevus and chalazion are respectively the most common lesion in men and women. Benign lesions were more common in women located more in upper lid, though there was no statistically difference between right and left lid.

  18. Numa Manson on velocity deficits and detonation stability. An invited memorial lecture presented at ICDERS 21

    Science.gov (United States)

    Murray, S. B.

    2008-09-01

    This memorial paper pays tribute to Professor Numa Manson’s contributions to the understanding of detonation velocity deficits and wave stability. Manson and his colleague Guénoche postulated that a velocity deficit exists in a tube because the chemical reactions are inhibited in a thin layer adjacent to the tube walls. The hydrodynamic theory of detonation was modified to account for this, and it was shown that the deficit varies inversely with the tube diameter. Manson and his students measured detonation velocities in tubes of various diameter. An estimate of the detonation velocity for an infinite tube diameter was obtained by plotting the velocity against the reciprocal of the tube diameter, {φ^{-1}} , and extrapolating the line through the data to {φ^{-1}=0} . The relative contributions of tube geometry and surface roughness to the deficits were systematically studied. Manson was also one of the early investigators to shed light on the cellular structure of detonation by reporting “vibratory phenomena” seen as striations in streak schlieren photographs. An attempt was made to relate this phenomenon to “dispersions” in the propagation velocity and hence the wave stability. The author has extended Manson’s work by investigating detonations in tubes with yielding walls. Whereas boundary layers were responsible for the gasdynamic expansion and deficits in Manson’s rigid tubes, it was the moving boundaries that caused similar effects in the author’s investigations. The author has repeated the “nozzle” analysis of Fay and Dabora using the detonation cell length as the relevant chemical kinetic length scale, and found reasonable agreement between his experimental results and the model. When the Poitiers data are reinterpreted in light of the modified model, the trends are described quite well. More recent studies have shown that the measured deficits for mixtures characterized by irregular cellular structures do not agree with the Fay

  19. Characterizing the energy output generated by a standard electric detonator using shadowgraph imaging

    Science.gov (United States)

    Petr, V.; Lozano, E.

    2017-09-01

    This paper overviews a complete method for the characterization of the explosive energy output from a standard detonator. Measurements of the output of explosives are commonly based upon the detonation parameters of the chemical energy content of the explosive. These quantities provide a correct understanding of the energy stored in an explosive, but they do not provide a direct measure of the different modes in which the energy is released. This optically based technique combines high-speed and ultra-high-speed imaging to characterize the casing fragmentation and the detonator-driven shock load. The procedure presented here could be used as an alternative to current indirect methods—such as the Trauzl lead block test—because of its simplicity, high data accuracy, and minimum demand for test repetition. This technique was applied to experimentally measure air shock expansion versus time and calculating the blast wave energy from the detonation of the high explosive charge inside the detonator. Direct measurements of the shock front geometry provide insight into the physics of the initiation buildup. Because of their geometry, standard detonators show an initial ellipsoidal shock expansion that degenerates into a final spherical wave. This non-uniform shape creates variable blast parameters along the primary blast wave. Additionally, optical measurements are validated using piezoelectric pressure transducers. The energy fraction spent in the acceleration of the metal shell is experimentally measured and correlated with the Gurney model, as well as to several empirical formulations for blasts from fragmenting munitions. The fragment area distribution is also studied using digital particle imaging analysis and correlated with the Mott distribution. Understanding the fragmentation distribution plays a critical role when performing hazard evaluation from these types of devices. In general, this technique allows for characterization of the detonator within 6-8% error

  20. A 3-D simulation tool for hydrogen detonation during severe accident and its application

    International Nuclear Information System (INIS)

    Huang, T.; Zhang, Y.P.; Tian, W.X.; Su, G.H.; Qiu, S.Z.

    2017-01-01

    Highlights: • DEST has been developed by using High resolution scheme, ASIRK-2B method and multi-blocking patching method. • The DEST is verified and applied to the detonation experiment of RUT facility. • DEST can be used to analyze the pressure and temperature load of hydrogen detonation process. - Abstract: A 3-D simulation tool (DEST, Detonation Simulation tool) for hydrogen detonation during severe accident has been developed. The compressible three-dimensional Euler equations in Cartesian coordinate system are solved by a second-order additive semi-implicit Runge–Kutta method with 5th weighted essentially non-oscillatory scheme (WENO) and Steger-warming flux vector splitting approach handling the convection flux. The multi-blocking patching method is used to handle the flow problem of complex geometry. Afterward, the hydrodynamics solver is tested by applying DEST to the classical shock tube problems, and the results show that hydrodynamics solver can capture the shock wave correctly and give a detailed description of shock wave even if the gradient of pressure, density or velocity is large. Then two detonation experimental tests of RUT facility are simulated by DEST, and the comparisons between the predicted results and experimental data show a reasonably good agreement. Furthermore, DEST is applied to a hypothetical detonation in two connected compartments of containment. The predicted results show that the maximum pressure and temperature always occur at the corner of the compartment. The influence of ignition position is analyzed and the results show that the pressure tended to be larger when the mixture is ignited at a farther location. The DEST can be used to analyze the pressure and temperature load during detonation process under severe accident and has guidance on the strategy of hydrogen mitigation.

  1. Experimental investigation on valveless air-breathing dual-tube pulse detonation engines

    International Nuclear Information System (INIS)

    Peng, Changxin; Fan, Wei; Zheng, Longxi; Wang, Zhiwu; Yuan, Cheng

    2013-01-01

    Two-phase dual-tube air-breathing pulse detonation engine (APDE) experiments were performed to improve the understanding of the characteristics of valveless multi-tube APDE. Two different operation patterns were studied: simultaneously and single-tube firing. The synchronicity of detonation waves was quantified. The time interval was less than 1 ms and decreased with the increasing frequency. It was found which detonation wave arrived firstly had a degree of randomness. The situation that the detonation wave in a certain tube always kept ahead never happened in the experiments. The back-propagation pressure wave in the upstream inlet was also not synchronous. Its synchronicity was a little inferior than the detonation wave's and also improved with the increasing frequency. The pressure-rise occurred twice successively in the common air inlet and prolonged the period of pressure oscillations therein. The results of single-tube firing showed that the flow field in the non-detonate chamber was not only influenced by the diffracted wave downstream from the neighboring tube but also by the upstream-propagating pressure wave. Compared with the dual-tube firing, the operation pattern of single-tube firing is beneficial to reduce the pressure disturbance in the common air inlet. -- Highlights: ► Two-phase dual-tube APDE experiments were performed. ► The synchronicity of detonation waves was quantified. ► The synchronicity of back-propagation pressure was quantified. ► The flow field under different operation patterns were studied

  2. 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.

  3. Numerical study of multiscale compaction-initiated detonation

    Science.gov (United States)

    Gambino, J. R.; Schwendeman, D. W.; Kapila, A. K.

    2018-02-01

    A multiscale model of heterogeneous condensed-phase explosives is examined computationally to determine the course of transient events following the application of a piston-driven stimulus. The model is a modified version of that introduced by Gonthier (Combust Sci Technol 175(9):1679-1709, 2003. https://doi.org/10.1080/00102200302373) in which the explosive is treated as a porous, compacting medium at the macro-scale and a collection of closely packed spherical grains capable of undergoing reaction and diffusive heat transfer at the meso-scale. A separate continuum description is ascribed to each scale, and the two scales are coupled together in an energetically consistent manner. Following piston-induced compaction, localized energy deposition at the sites of intergranular contact creates hot spots where reaction begins preferentially. Reaction progress at the macro-scale is determined by the spatial average of that at the grain scale. A parametric study shows that combustion at the macro-scale produces an unsteady detonation with a cyclical character, in which the lead shock loses strength and is overtaken by a stronger secondary shock generated in the partially reacted material behind it. The secondary shock in turn becomes the new lead shock and the process repeats itself.

  4. 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.

  5. Measurement of the pressure pulse from a detonating explosive

    International Nuclear Information System (INIS)

    Bourne, N K; Milne, A M; Biers, R A

    2005-01-01

    A series of experiments has been carried out to determine the pressure pulse exiting from a polymethylmethacrylate (PMMA) plate, of varying thickness, subject to the shock pulse exerted by a detonating charge of fixed mass. This calibration will define a new donor explosive and inert gap material for use in one of the qualification tests for energetic materials, the large scale gap test. The peak pressure was recorded on the central axis of the attenuator using calibrated piezoresistive manganin gauges as a function of the quantity of PMMA applied to the output of the donor charge. The stress history within the PMMA was measured as a function of run distance and the peak pressure plotted against thickness as a calibration. The shock front was known to have curvature and a measurement of this was attempted. The behaviour of the transmitted shock at small gap thicknesses was shown to be anomalous since the front was partially in a reactive and partially within an inert medium

  6. Temporally resolved infrared spectra from the detonation of advanced munitions

    Science.gov (United States)

    Gordon, Joe Motos; Gross, Kevin C.; Perram, Glen P.

    2009-05-01

    A suite of instruments including a 100 kHz 4-channel radiometer, a rapid scanning Fourier-transform infrared spectrometer, and two high-speed visible imagers was used to observe the detonation of several novel insensitive munitions being developed by the Air Force Research Laboratory. The spectral signatures exhibited from several different explosive compositions are discernable and may be exploited for event classification. The spectra are initially optically thick, resembling a Planckian distribution. In time, selective emission in the wings of atmospheric absorption bands becomes apparent, and the timescale and degree to which this occurs is correlated with aluminum content in the explosive formulation. By analyzing the high-speed imagery in conjunction with the time-resolved spectral measurements, it may be possible to interpret these results in terms of soot production and oxidation rates. These variables allow for an investigation into the chemical kinetics of explosions and perhaps reveal other phenomenology not yet readily apparent. With an increased phenomenological understanding, a model could be created to explain the kinetic behavior of the temperature and by-product concentration profiles and thus improve the ability of military sensing platforms to identify explosive types and sources.

  7. Optical limiting in suspension of detonation nanodiamonds in engine oil

    Science.gov (United States)

    Mikheev, Konstantin G.; Krivenkov, Roman Yu.; Mogileva, Tatyana N.; Puzyr, Alexey P.; Bondar, Vladimir S.; Bulatov, Denis L.; Mikheev, Gennady M.

    2017-07-01

    The optical limiting (OL) of detonation nanodiamond (DND) suspensions in engine oil was studied at a temperature range of 20°C to 100°C. Oil suspensions were prepared on the basis of the DNDs with an average nanoparticle cluster size in hydrosols (Daver) of 50 and 110 nm. Raman spectroscopy was used to characterize the samples. The OL investigation was carried out by the z-scan technique. The fundamental (1064 nm) and second (532 nm) harmonic radiations of YAG:Nd3+ laser with passive Q-switching as an excitation source were used. The OL thresholds for both suspensions at 532 and 1064 nm were determined. It is shown that a decrease in the average nanoparticle cluster size as well as an increase of the wavelength of the incident radiation leads to the OL threshold increase. It is established that the OL performance is not influenced by increasing the temperature from 20°C to 100°C. The results obtained show the possibility of using the DNDs suspensions in engine oil as an optical limiter in a wide temperature range.

  8. Results from a high speed pyrometer measuring detonating explosive

    Science.gov (United States)

    Richley, James; Ferguson, James

    2017-06-01

    High speed pyrometry has been deployed on two series of cylinder test experiments in order to investigate its ability to measure the temperature of a detonating explosive. The pyrometer fielded on the first series of cylinder tests consisted of two, three channel systems fed by optical fibres. The optical fibres were placed such that they observed the exposed explosive at the end of the cylinder (through a lithium fluoride window). In addition an optical emission spectrometer was used to capture the emission spectrum from the same area of the explosive. The pyrometer design was then modified to produce a six-channel system, which incorporated detectors with rise times on the order of 1 ns, this was tested on a second series of cylinder tests. Half of the cylinder tests in the second series were performed without a LiF window. Results from the second series of experiments are reported and compared with those from the first series. Initial analysis suggests that the temperature observed was at least 3700 K.

  9. Laser-supported detonation waves and pulsed laser propulsion

    International Nuclear Information System (INIS)

    Kare, J.

    1990-01-01

    A laser thermal rocket uses the energy of a large remote laser, possibly ground-based, to heat an inert propellant and generate thrust. Use of a pulsed laser allows the design of extremely simple thrusters with very high performance compared to chemical rockets. The temperatures, pressures, and fluxes involved in such thrusters (10 4 K, 10 2 atmospheres, 10 7 w/cm 2 ) typically result in the creation of laser-supported detonation (LSD) waves. The thrust cycle thus involves a complex set of transient shock phenomena, including laser-surface interactions in the ignition of the LSD wave, laser-plasma interactions in the LSD wave itself, and high-temperature nonequilibrium chemistry behind the LSD wave. The SDIO Laser Propulsion Program is investigating these phenomena as part of an overall effort to develop the technology for a low-cost Earth-to-orbit laser launch system. We will summarize the Program's approach to developing a high performance thruster, the double-pulse planar thruster, and present an overview of some results obtained to date, along with a discussion of the many research question still outstanding in this area

  10. Instrumentation techniques for monitoring shock and detonation waves

    Science.gov (United States)

    Dick, R. D.; Parrish, R. L.

    1985-09-01

    CORRTEX (Continuous Reflectometry for Radius Versus Time Experiments), SLIFER (Shorted Location Indication by Frequency of Electrical Resonance), and pin probes were used to monitor several conditions of blasting such as the detonation velocity of the explosive, the functioning of the stemming column confining the explosive, and rock mass motion. CORRTEX is a passive device that employs time-domain reflectometry to interrogate the two-way transit time of a coaxial cable. SLIFER is an active device that monitors the changing frequency resulting from a change in length of a coaxial cable forming an element of an oscillator circuit. Pin probes in this application consist of RG-174 coaxial cables, each with an open circuit, placed at several known locations within the material. Each cable is connected to a pulse-forming network and a voltage source. When the cables are shorted by the advancing wave, time-distance data are produced from which a velocity can be computed. Each technique, installation of the gauge, examples of the signals, and interpretation of the records are described.

  11. Ureteritis cystica: A rare benign lesion

    Directory of Open Access Journals (Sweden)

    F. Ibrahim

    2014-09-01

    Full Text Available Ureteritis cystica is an uncommon benign pathology of the ureter. The etiology is unclear but the diagnosis has become much easier to make with the routine use of ureteroscopy for diagnosis of ureteric lesions. We present a case of a 63 year old Sudanese woman with a history of repeated attacks of right loin pain in whom magnetic resonance urography (MRU showed multiple filling defects in the right ureter. These were initially thought to be malignant urothelial lesions. Ureteroscopy revealed cystic smooth walled masses which discharged tiny turbid fluid on biopsy. An intraoperative diagnosis of ureteritis cystica was confirmed. The patient was managed conservatively.

  12. Impact of radiation therapy for benign diseases

    International Nuclear Information System (INIS)

    Kantor, G.; Van Houtte, P.; Beauvois, S.; Roelandts, M.

    1997-01-01

    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)

  13. Benign intracranial hypertension diagnosed with bilateral papilloedema

    Directory of Open Access Journals (Sweden)

    K. C. Phillips

    2013-12-01

    Full Text Available This article presents a case of benign intracranial hypertension (BIH diagnosed from the presence of papilloedema. This potentially sight-threatening condition particularly affects younger obese females and can be idiopathic, caused by adverse reaction to certain prescription medications or by systemic disease. Prompt treatment is essentialto avoid optic atrophy and low energy diet and exercise forms part of long-term treatment to avoid relapse. Optometrists can play a critical primary health care role in the detection of papilloedema and referring appropriately.

  14. Differential diagnosis of benign intrahepatic tumours

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, R.; Herter, M.

    1983-01-01

    Differential diagnosis of benign intrahepatic tumours can be very difficult despite numerous non-invasive diagnostic approaches, as is evident from two case reports presented here. The problem appears particularly intricate if two or more masses or space-occupying growths are present at the same time, the diagnostic aspects being different. In the first case, echinococcus alveolaris occurred simultaneously with a cavernous haemangioma and a focal nodular hyperplasia (FNH). In the second case, FNH as a pendulating tumour was combined with a second focus in the superior part of the liver. These two examples are used as basis for discussing various diagnostic approaches, such as sonography, computed tomography and scintiscanning.

  15. 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.

  16. Experimental study of detonation of large-scale powder-droplet-vapor mixtures

    Science.gov (United States)

    Bai, C.-H.; Wang, Y.; Xue, K.; Wang, L.-F.

    2018-01-01

    Large-scale experiments were carried out to investigate the detonation performance of a 1600-m3 ternary cloud consisting of aluminum powder, fuel droplets, and vapor, which were dispersed by a central explosive in a cylindrically stratified configuration. High-frame-rate video cameras and pressure gauges were used to analyze the large-scale explosive dispersal of the mixture and the ensuing blast wave generated by the detonation of the cloud. Special attention was focused on the effect of the descending motion of the charge on the detonation performance of the dispersed ternary cloud. The charge was parachuted by an ensemble of apparatus from the designated height in order to achieve the required terminal velocity when the central explosive was detonated. A descending charge with a terminal velocity of 32 m/s produced a cloud with discernably increased concentration compared with that dispersed from a stationary charge, the detonation of which hence generates a significantly enhanced blast wave beyond the scaled distance of 6 m/kg^{1/3} . The results also show the influence of the descending motion of the charge on the jetting phenomenon and the distorted shock front.

  17. Qualification of a multi-diagnostic detonator-output characterization procedure utilizing PMMA witness blocks

    Science.gov (United States)

    Biss, Matthew; Murphy, Michael; Lieber, Mark

    2017-06-01

    Experiments were conducted in an effort to qualify a multi-diagnostic characterization procedure for the performance output of a detonator when fired into a poly(methyl methacrylate) (PMMA) witness block. A suite of optical diagnostics were utilized in combination to both bound the shock wave interaction state at the detonator/PMMA interface and characterize the nature of the shock wave decay in PMMA. The diagnostics included the Shock Wave Image Framing Technique (SWIFT), a photocathode tube streak camera, and photonic Doppler velocimetry (PDV). High-precision, optically clear witness blocks permitted dynamic flow visualization of the shock wave in PMMA via focused shadowgraphy. SWIFT- and streak-imaging diagnostics captured the spatiotemporally evolving shock wave, providing a two-dimensional temporally discrete image set and a one-dimensional temporally continuous image, respectively. PDV provided the temporal velocity history of the detonator output along the detonator axis. Through combination of the results obtained, a bound was able to be placed on the interface condition and a more-physical profile representing the shock wave decay in PMMA for an exploding-bridgewire detonator was achieved.

  18. The Dependence of Ammonal Detonation Product Energy on Cylinder Test Scale

    Science.gov (United States)

    Anderson, Eric; Jackson, Scott

    2017-06-01

    For a detonation to propagate steadily, the compression shock must be supported by a sufficient amount of energy from the chemical reaction zone. Flow divergence reduces the available energy to drive the detonation forward, resulting in the diameter-effect and eventually detonation failure as charge size is reduced. Similarly, product energy tends to decrease with decreasing charge size. Non-ideal explosives such as Ammonium Nitrate blended with Aluminum Powder (Ammonal) are particularly sensitive to flow divergence. To quantify the effect of flow divergence on Ammonal performance, we applied an analytic method to examine cylinder test wall velocity profiles from Ammonal tests with inner diameters of 12.7 mm up to 76.2 mm. For these tests, we report detonation velocity and detonation product isentropes and energies. In addition, analysis of the velocity profiles revealed an experimental measurement of the Rayleigh line, which agreed well with the theoretical Rayleigh line for all experiments. Using this feature we are able to report inferred reaction zone times.

  19. Fast Reactions of Aluminum and Explosive Decomposition Products in a Post-Detonation Environment

    Science.gov (United States)

    Tappan, Bryce; Manner, Virginia; Lloyd, Joseph; Pemberton, Steven; Explosives Applications; Special Projects Team

    2011-06-01

    In order to determine the reaction behavior of Al in HMX/cast-cured binder formulations shortly after the passage of the detonation, a series of cylinder tests was performed on formulations with varying amounts of 2 μm spherical Al as well as LiF (an inert surrogate for Al). In these studies, both detonation velocity and cylinder expansion velocity are measured in order to determine exactly how and when Al contributes to the explosive event, particularly in the presence of oxidizing/energetic binders. The U.S. Army ARDEC at Picatinny has recently coined the term ``combined effects explosives'' for these materials as they demonstrate both high metal pushing capability and high blast ability. This study is aimed at developing a fundamental understanding of the reaction of Al with explosives decomposition products, where both the detonation and post-detonation environment are analyzed. Reaction rates of Al metal are determined via comparison of predicted performance based on thermoequilibrium calculations. The JWL equation of state, detonation velocities, wall velocities, and parameters at the C-J plane are some of the parameters that will be discussed.

  20. Effect of Vertical Concentration Gradient on Globally Planar Detonation with Detailed Reaction Mechanism

    Science.gov (United States)

    Song, Qingguana; Wang, Cheng; Han, Yong; Gao, Dayuan; Duan, Yingliang

    2017-06-01

    Since detonation often initiates and propagates in the non-homogeneous mixtures, investigating its behavior in non-uniform mixtures is significant not only for the industrial explosion in the leakage combustible gas, but also for the experimental investigations with a vertical concentration gradient caused by the difference in the molecular weight of gas mixture. Objective of this work is to show the detonation behavior in the mixture with different concentration gradients with detailed chemical reaction mechanism. A globally planar detonation in H2-O2 system is simulated by a high-resolution code based on the fifth-order weighted essentially non-oscillatory (WENO) scheme in spatial discretization and the third-order Additive Runge-Kutta schemes in time discretization. The different shocked combustion modes appear in the rich-fuel and poor-fuel layers due to the concentration gradient effect. Globally, for the cases with the lower gradient detonation can be sustained in a way of the alternation of the multi-heads mode and single-head mode, whereas for the cases with the higher gradient detonation propagates with a single-head mode. Institute of Chemical Materials, CAEP.

  1. Surgery versus pharmacotherapy of benign thyroid diseases

    International Nuclear Information System (INIS)

    Younes, Nidal A.; Albousal, Abla M.

    2003-01-01

    Surgical management of thyroid diseases (BTDs) has been a topic of interest and confusion for many years. Almost 80% of thyroidectomies at an average endocrine surgical unit are carried out for BTDs.Resistance to surgical intervention in BTDs has been based on the belief that increased complication rate is inherent in its use, this is despite thepotential advatages in terms of confirming the benign nature of the lesion, controlling the disease, and relieving of local symptoms of large neck mass. Benign thyroid diseases are more likely to occur in middle-aged woman living in iodine deficient areas, or have a family history of goiter, or in patients taking iodine-containig drugs, like amoidarone, or in patients with previous history of x-ray exposure. However, the physician must be carefull in making the diagnosis of BTDsin patients of extremes of age or in presence of positive history of radiation, or in patients with family history of thyroid or colon cancer . In this atricle we will review the etiology,epidemiology , diagonastic methodologiesand the recent trends in the sugical and medical mangement of BTDs. (author)

  2. 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.

  3. Benign prostatic hyperplasia: epidemiology, economics and evaluation.

    Science.gov (United States)

    Vuichoud, Camille; Loughlin, Kevin R

    2015-10-01

    Benign prostatic hyperplasia (BPH) is arguably the most common benign disease of mankind. As men age, the prostate inexorably grows often causing troubling symptoms causing them to seek out care. While traditionally treated by transurethral resection or open surgical removal of the hypertrophied adenoma, today the urologist has numerous medical, surgical and minimally invasive techniques available. In this supplement The Canadian Journal of Urology provides a review of the various techniques and medications available today. As an introduction to the supplement, the aim of this article is to review the epidemiology and economy of BPH as well as its natural history and diagnosis. A systematic review of available literature was looking for articles on BPH and its epidemiology, economics, natural history and management using PubMed database. The prevalence of this condition is increasing with the population aging and so does the economic burden. The exact etiology of this condition is unknown, but some risk factors have been identified. The diagnostic and treatment of this very common disease should rely on a strong collaboration between primary care physician and urologist. There are multiple options in treating BPH including medical, surgical and newer minimally invasive options. The challenge with having a variety of options is to review them with the patient and help the patient select the best treatment option for their condition.

  4. Intraosseous Benign Lesions of the Jaws: A Radiographic Study

    OpenAIRE

    Javadian Langaroodi, Adineh; Lari, Sima Sadat; Shokri, Abbas; Hoseini Zarch, Seyed Hossein; Jamshidi, Shokofeh; Akbari, Peyman

    2014-01-01

    Background: Benign maxillo-mandibular tumors and cysts, which are relatively common findings on radiographs, namely the ubiquitous panoramic view, have to be dealt with by dentists on a daily basis. Objectives: The aim of this study is to evaluate the panoramic radiographic findings pertaining to benign and tumoral lesions in the maxilla and mandible. Patients and Methods: Applying a case series method, panoramic images of 61 patients with cysts, benign tumors and tumor-like lesions in the ja...

  5. Benign Angiomyolipoma with Renal Vein Invasion: A Case Report

    International Nuclear Information System (INIS)

    Kim, Mi Seon; Park, Soo Youn; Hwang, Seong Su

    2009-01-01

    Angiomyolipomas are the most common type of benign renal tumors and are characterized by a mixture of mature adipose tissue, sheet of smooth muscle, and thick-walled blood vessels of various proportions. Several cases of angiomyolipoma with partial malignant transformation invading the adjacent structure and lymph node have been reported. On the other hand, benign angiomyolipomas invading the adjacent structures has been rarely reported. We report a case of a benign angiomyolipoma with renal vein invasion

  6. Benign Paroxysmal Positional Vertigo After Nonotologic Surgery: Case Series

    OpenAIRE

    Kansu, Leyla; Aydin, Erdinc; Gulsahi, Kamran

    2012-01-01

    Benign paroxysmal positional vertigo is one of the most common types of vertigo caused by peripheral vestibular dysfunction. Although head trauma, migraine, long-term bed rest, Ménière disease, viral labyrinthitis, and upper respiratory tract infections are believed to be predisposing factors, most cases of benign paroxysmal positional vertigo are idiopathic. Ear surgery is another cause, but after non-otologic surgery, attacks of benign paroxysmal positional vertigo are rare. We describe thr...

  7. Benign cementoblastoma: A rare case report with review of literature

    Directory of Open Access Journals (Sweden)

    Neeta Sharma

    2014-01-01

    Full Text Available We present a rare case of radiopaque lesion with radiolucent rim in the right body of mandible, with history of extraction of involved tooth, which made diagnosis confusing unless pre-extraction intraoral periapical radiography radiograph was recovered, finally diagnosed as benign cementoblastoma. It was surgically managed, with no recurrence of the lesion more than 2 years of follow-up. Benign cementoblastoma is a rare, benign tumor of odontogenic ectomesenchymal origin, usually associated with roots of first mandibular molar.

  8. The influence of small additions of diethylenetriamine on the detonation waves stability for nitromethane/acetone solution

    Science.gov (United States)

    Mochalova, V.; Utkin, A.

    2014-05-01

    Instability of detonation front in the nitromethane/acetone (NM/A) solution was observed in our previous work: at 10% of acetone the amplitude of heterogeneities was about 20 microns and at 20% of acetone this size was 50 microns. It is known that small additions of diethylenetriamine (DETA) considerably increase the initial rate of chemical reaction in detonation waves for NM. It was expected that DETA would influence the stability of detonation waves in the NM/A solution too. To investigate this phenomenon the laser interferometer VISAR was used for the recording of particle velocity profiles in detonation waves for NM/A. It was found that at the addition of 0.5% DETA to NM/A 90/10 the oscillations in the velocity profile decreased several times over. At the addition of 1% DETA the profile is smooth, i.e. the heterogeneities disappear and detonation wave becomes steady-state. In NM/A 80/20 at the addition of 5% DETA the heterogeneities size is reduced by the order. The increase of detonation wave velocity of NM/A grater than 1% was observed at small concentrations of DETA. Thus it was found that small additions of DETA to the NM/A solution with an unstable detonation front resulted not only in the decrease of heterogeneities size but in their disappearance and stabilization of detonation waves.

  9. Deflagration to Detonation Transition (DDT) Simulations of HMX Powder Using the HERMES Model

    Science.gov (United States)

    White, Bradley; Reaugh, John; Tringe, Joseph

    2017-06-01

    We performed computer simulations of DDT experiments with Class I HMX powder using the HERMES model (High Explosive Response to MEchanical Stimulus) in ALE3D. Parameters for the model were fitted to the limited available mechanical property data of the low-density powder, and to the Shock to Detonation Transition (SDT) test results. The DDT tests were carried out in steel-capped polycarbonate tubes. This arrangement permits direct observation of the event using both flash X-ray radiography and high speed camera imaging, and provides a stringent test of the model. We found the calculated detonation transition to be qualitatively similar to experiment. Through simulation we also explored the effects of confinement strength, the HMX particle size distribution and porosity on the computed detonation transition location. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.

  10. Novel measurements of shock pressure decay in PMMA using detonator loading

    Science.gov (United States)

    Murphy, Michael; Lieber, Mark; Biss, Matthew

    2017-06-01

    An empirical model equation for shock pressure decay in PMMA was determined through a unique set of experiments employing detonator loading. Custom polymethyl methacrylate (PMMA) witness blocks were designed with monolithic architecture to house precise PMMA gap thicknesses ranging from 0-10 mm in 1 mm increments. The PMMA gaps separated detonator working surfaces from windowed photonic Doppler velocimetry (PDV) probes, and were designed to provide undistorted optical access to ultra-high-speed framing and digital streak cameras. The shock wave image framing technique (SWIFT), and a new laser-backlit digital streak diagnostic, simultaneously captured the temporal evolution of detonator-induced diverging shock waves within the PMMA gaps. The PDV diagnostic measured critical mass velocity histories as the shocks exited the variable gap thicknesses. The multi-diagnostic data package was used to characterize the shock pressure decay in PMMA as a function of shock propagation time and PMMA thickness.

  11. Investigations on deflagration to detonation transition in porous energetic materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, D.S. [Univ. of Illinois, Urbana, IL (United States)

    1999-07-01

    The research carried out by this contract was part of a larger effort funded by LANL in the areas of deflagration to detonation in porous energetic materials (DDT) and detonation shock dynamics in high explosives (DSD). In the first three years of the contract the major focus was on DDT. However, some researchers were carried out on DSD theory and numerical implementation. In the last two years the principal focus of the contract was on DSD theory and numerical implementation. However, during the second period some work was also carried out on DDT. The paper discusses DDT modeling and DSD modeling. Abstracts are included on the following topics: modeling deflagration to detonation; DSD theory; DSD wave front tracking; and DSD program burn implementation.

  12. Research on verification and validation strategy of detonation fluid dynamics code of LAD2D

    Science.gov (United States)

    Wang, R. L.; Liang, X.; Liu, X. Z.

    2017-07-01

    The verification and validation (V&V) is an important approach in the software quality assurance of code in complex engineering application. Reasonable and efficient V&V strategy can achieve twice the result with half the effort. This article introduces the software-Lagrangian adaptive hydrodynamics code in 2D space (LAD2D), which is self-developed software in detonation CFD with plastic-elastic structure. The V&V strategy of this detonation CFD code is presented based on the foundation of V&V methodology for scientific software. The basic framework of the module verification and the function validation is proposed, composing the detonation fluid dynamics model V&V strategy of LAD2D.

  13. Population inversion and laser effect in gas flows due to explosion or detonation

    Science.gov (United States)

    Korobeinikov, V. P.; Podduev, M. I.

    The influence of the gas flow behind blast and detonation waves on population inversion of the vibrational levels of CO2 in a CO2-N2-He-H2O mixture was studied by the numerical solution of nonequilibrium gasdynamic equations. The following cases were examined: (1) the propagation of a cylindrical blast wave (generated by the explosion of cylindrically confined RDX or acetylene-oxygen mixture charges) in an active medium, (2) detonation wave propagation in a nozzle filled with a combustible mixture, and (3) expansion of acetylene-air mixture detonation products into vacuum. The optimization questions of gasdynamic processes and emission radiation in pulse gasdynamic lasers were discussed as well. The results suggest that the potential for a population inversion is influenced by the finite dimensions of the charge, the variations in density of the explosive mixture, and the opportunity for expansion of the active medium after shock heating.

  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. Optimization long hole blast fragmentation techniques and detonating circuit underground uranium mine stope

    International Nuclear Information System (INIS)

    Li Qin; Yang Lizhi; Song Lixia; Qin De'en; Xue Yongshe; Wang Zhipeng

    2012-01-01

    Aim at high rate of large blast fragmentation, a big difficulty in long hole drilling and blasting underground uranium mine stope, it is pointed out at the same time of taking integrated technical management measures, the key is to optimize the drilling and blasting parameters and insure safety the act of one that primes, adopt 'minimum burden' blasting technique, renew the stope fragmentation process, and use new process of hole bottom indirect initiation fragmentation; optimize the detonating circuit and use safe, reliable and economically rational duplex non-electric detonating circuit. The production practice shows that under the guarantee of strictly controlled construction quality, the application of optimized blast fragmentation technique has enhanced the reliability of safety detonation and preferably solved the problem of high rate of large blast fragments. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Ann S.; Brandt, Larry D.

    2011-12-01

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

  17. 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.

  18. 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.)

  19. Gasdynamics of detonations and explosions. International colloquium on gasdynamics of explosions and reactive systems, 7th, Gottingen, West Germany, August 20-24, 1979, technical papers

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, J.R.; Manson, N.; Oppenheim, A.K.; Soloukhin, R.I.

    1981-01-01

    Wall and confinement effects are considered along with liquid and solid phase phenomena, the cellular structure of detonations, and detonations at moderate pressures. Attention is given to turbulent flame propagation and acceleration in the presence of obstacles, the detonation of unconfined fuel aerosols, the initiation of unconfined gas detonations in hydrocarbon-air mixtures by a sympathetic mechanism, a detection method for the deflagration to detonation transition in gaseous explosive mixtures, the influence of the nature of confinement on gaseous detonation, mechanical effects of gaseous detonations on a flexible confinement, the pressure evolution behind spherical and hemispherical detonations in gases, molecular dynamics of shock and detonation phenomena in condensed matter, TNT explosions in a hard vacuum, the effect of the shock-wave front on the origin of reaction, induction delay and detonation failure diameter of nitromethane mixtures, the critical area concept for the initiation of a solid high explosive by the impact of small projectiles, the shock initiation of hydrazine mononitrate, the characterization of mass flow rates for various percussion primers, the diffraction of a planar detonation in various fuel-oxygen mixtures at an area change, and the detonation characteristics of two ethylene-oxygen-nitrogen mixtures containing aluminum particles in suspension.

  20. Empirical equation of state of the products of the detonation of a liquid explosive based on mixtures of tetranitromethane and nitrobenzene of various compositions

    International Nuclear Information System (INIS)

    Adigamova, T.A.; Davydov, N.B.

    2012-01-01

    The equation of state of the products of the detonation of liquid explosives has been derived by theoretical analysis and calculations. The dependence of the detonation rate on the oxygen balance has been obtained using the existing data on the physicomechanical and detonation properties of liquid explosive mixtures. Calculation dependences of the density on the weight content of nitrobenzene have been obtained [ru