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https://www.readbyqxmd.com/read/28542917/characterizing-the-performance-of-pipe-bombs
#1
Jimmie C Oxley, James L Smith, Evan T Bernier, Fredrick Sandstrom, Gregory G Weiss, Gunther W Recht, David Schatzer
Pipe bombs of steel or PVC fragment in reproducible patterns when similarly configured. The power of the explosion correlates with number, mass, and size of the fragments recovered, where a large number of small, low-mass fragments indicate a high-power event and vice versa. In discussing performance, describing pipe fragmentation pattern by fragment weight distribution mapping (FWDM) or fragment surface area distribution mapping (FSADM) was useful. When fillers detonated, detonation velocities of ~4.4 mm/μs were measured...
May 24, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28526787/development-of-multi-well-plate-methods-using-pure-cultures-of-methanogens-to-identify-new-inhibitors-for-suppressing-ruminant-methane-emissions
#2
M R Weimar, J Cheung, D Dey, C McSweeney, M Morrison, Y Kobayashi, W B Whitman, V Carbone, L R Schofield, R S Ronimus, G M Cook
Hydrogenotrophic methanogens typically require strictly anaerobic culturing conditions in glass tubes with overpressures of H2 and CO2 that are both time-consuming and costly. To increase the throughput for screening chemical compound libraries, 96-well microtiter plate methods for the growth of a marine (environmental) methanogen Methanococcus maripaludis strain S2 and the rumen methanogen Methanobrevibacter species AbM4 were developed. A number of key parameters (inoculum size, reducing agents for media preparation, duration of assay, inhibitor solvents and culture volume) were optimised to achieve robust and reproducible growth in a high-throughput microtiter plate format...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28508893/south-american-plate-advance-and-forced-andean-trench-retreat-as-drivers-for-transient-flat-subduction-episodes
#3
Gerben Schepers, Douwe J J van Hinsbergen, Wim Spakman, Martha E Kosters, Lydian M Boschman, Nadine McQuarrie
At two trench segments below the Andes, the Nazca Plate is subducting sub-horizontally over ∼200-300 km, thought to result from a combination of buoyant oceanic-plateau subduction and hydrodynamic mantle-wedge suction. Whether the actual conditions for both processes to work in concert existed is uncertain. Here we infer from a tectonic reconstruction of the Andes constructed in a mantle reference frame that the Nazca slab has retreated at ∼2 cm per year since ∼50 Ma. In the flat slab portions, no rollback has occurred since their formation at ∼12 Ma, generating 'horse-shoe' slab geometries...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28504823/centrifugal-driven-reduced-dimension-planar-chromatography
#4
Rachel B Strickhouser, Nahla A Hatab, Nickolay V Lavrik, Michael J Sepaniak
A fundamental problem with efficiency in capillary action driven planar chromatography results from diminishing flow rates as development proceeds, giving rise to molecular diffusion related band dispersion for most sample types. Overpressure and electrokinetic means to speed flow have been used successfully in TLC. We explore the use of centrifugal force (CF) to drive flow for reduced-dimension planar platforms (ultra-TLC, low μm features, and nano-TLC, nanoscale features). The silicon wafer platforms have two forms of continuous 2-D arrays created by either photolithography or metal dewetting followed by deep reactive ion etching and coated with porous SiO2 ...
May 15, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28504263/dehydration-driven-stress-transfer-triggers-intermediate-depth-earthquakes
#5
Thomas P Ferrand, Nadège Hilairet, Sarah Incel, Damien Deldicque, Loïc Labrousse, Julien Gasc, Joerg Renner, Yanbin Wang, Harry W Green Ii, Alexandre Schubnel
Intermediate-depth earthquakes (30-300 km) have been extensively documented within subducting oceanic slabs, but their mechanics remains enigmatic. Here we decipher the mechanism of these earthquakes by performing deformation experiments on dehydrating serpentinized peridotites (synthetic antigorite-olivine aggregates, minerals representative of subduction zones lithologies) at upper mantle conditions. At a pressure of 1.1 gigapascals, dehydration of deforming samples containing only 5 vol% of antigorite suffices to trigger acoustic emissions, a laboratory-scale analogue of earthquakes...
May 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28479675/understanding-the-densification-process-of-bi2sr2cacu2ox-round-wires-with-overpressure-processing-and-its-effect-on-critical-current-density
#6
M R Matras, J Jiang, D C Larbalestier, E E Hellstrom
Overpressure (OP) processing increases the critical current density (JC ) of Bi2Sr2CaCu2Ox (2212) round wires by shrinking the surrounding Ag matrix around the 2212 filaments, driving them close to full density and greatly increasing the 2212 grain connectivity. Indeed densification is vital for attaining the highest JC . Here, we investigate the time and temperature dependence of the wire densification. We find that the wire diameter decreases by 3.8 ± 0.3 % after full heat treatment at 50 atm and 100 atm OP...
October 2016: Superconductor Science & Technology
https://www.readbyqxmd.com/read/28438658/antioxidants-reduce-neurodegeneration-and-accumulation-of-pathologic-tau-proteins-in-the-auditory-system-after-blast-exposure
#7
Xiaoping Du, Matthew B West, Qunfeng Cai, Weihua Cheng, Donald L Ewert, Wei Li, Robert A Floyd, Richard D Kopke
Cochlear neurodegeneration commonly accompanies hair cell loss resulting from aging, ototoxicity, or exposures to intense noise or blast overpressures. However, the precise pathophysiological mechanisms that drive this degenerative response have not been fully elucidated. Our laboratory previously demonstrated that non-transgenic rats exposed to blast overpressures exhibited marked somatic accumulation of neurotoxic variants of the microtubule-associated protein, Tau, in the hippocampus. In the present study, we extended these analyses to examine neurodegeneration and pathologic Tau accumulation in the auditory system in response to blast exposure and evaluated the potential therapeutic efficacy of antioxidants on short-circuiting this pathological process...
April 22, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28419850/overpressure-blast-injury-induced-oxidative-stress-and-neuroinflammation-response-in-rat-frontal-cortex-and-cerebellum
#8
Hale Z Toklu, Zhihui Yang, Sehkar Oktay, Yasemin Sakarya, Nataliya Kirichenko, Michael K Matheny, Judy Muller-Delp, Kevin Strang, Philip J Scarpace, Kevin K W Wang, Nihal Tümer
BACKGROUND & AIM: Overpressure blast-wave induced brain injury (OBI) and its long-term neurological outcome pose significant concerns for military personnel. Our aim is to investigate the mechanism of injury due to OBI. METHODS: Rats were divided into 3 groups: (1) Control, (2) OBI (exposed 30psi peak pressure, 2-2.5ms), (3) Repeated OBI (r-OBI) (three exposures over one-week period). Lung and brain (cortex and cerebellum) tissues were collected at 24h post injury...
April 15, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28403239/simulated-blast-overpressure-induces-specific-astrocyte-injury-in-an-ex-vivo-brain-slice-model
#9
Saranya Canchi, Malisa Sarntinoranont, Yu Hong, Jeremy J Flint, Ghatu Subhash, Michael A King
Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood-brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue...
2017: PloS One
https://www.readbyqxmd.com/read/28402895/explosion-hazards-of-lpg-air-mixtures-in-vented-enclosure-with-obstacles
#10
Qi Zhang, Yaxing Wang, Zhen Lian
Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent...
April 1, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28329435/face-shield-design-against-blast-induced-head-injuries
#11
Long Bin Tan, Kwong Ming Tse, Yuan Hong Tan, Mohamad Ali Bin Sapingi, Vincent Beng Chye Tan, Heow Pueh Lee
Blast-induced traumatic brain injury (TBI) has been on the rise in recent years due to the increasing use of improvised explosive devices (IEDs) in conflict zones. Our study investigates the response of a helmeted human head subjected to a blast of 1 atm peak overpressure, for cases with and without a standard polycarbonate (PC) face shield and for face shields comprising of composite PC and aerogel materials and with lateral edge extension. The novel introduction of aerogel into the laminate face shield is explored and its wave-structure interaction mechanics and performance in blast mitigation is analysed...
March 22, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28290006/exercise-testing-and-stress-imaging-in-mitral-valve-disease
#12
REVIEW
Damien Voilliot, Patrizio Lancellotti
Mitral valve disease represented by mitral stenosis and mitral regurgitation is the second most frequent valvulopathy. Mitral stenosis leads to an increased left atrial pressure whereas mitral regurgitation leads to an increased left atrial pressure associated with a volume overload. Secondary to an upstream transmission of this overpressure, both mitral stenosis and regurgitation lead to pulmonary hypertension and right heart failure. In addition, mitral regurgitation also leads to left ventricular dilatation and dysfunction with left heart failure...
March 2017: Current Treatment Options in Cardiovascular Medicine
https://www.readbyqxmd.com/read/28289914/firecracker-eye-exposure-experimental-study-and-simulation
#13
Chiara Clemente, Luca Esposito, Domenico Speranza, Nicola Bonora
Understanding the mechanisms of traumatic ocular injury is helpful to make accurate diagnoses before the symptoms emerge and to develop specific eye protection. The comprehension of the dynamics of primary blast injury mechanisms is a challenging issue. The question is whether the pressure wave propagation and reflection alone could cause ocular damage. To date, there are dissenting opinions and no conclusive evidence thereupon. A previous numerical investigation of blast trauma highlighted the dynamic effect of pressure propagation and its amplification by the geometry of the bony orbit, inducing a resonance cavity effect and a standing wave hazardous for eye tissues...
March 13, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28273951/vein-networks-in-hydrothermal-systems-provide-constraints-for-the-monitoring-of-active-volcanoes
#14
Luigi Cucci, Francesca Di Luccio, Alessandra Esposito, Guido Ventura
Vein networks affect the hydrothermal systems of many volcanoes, and variations in their arrangement may precede hydrothermal and volcanic eruptions. However, the long-term evolution of vein networks is often unknown because data are lacking. We analyze two gypsum-filled vein networks affecting the hydrothermal field of the active Lipari volcanic Island (Italy) to reconstruct the dynamics of the hydrothermal processes. The older network (E1) consists of sub-vertical, N-S striking veins; the younger network (E2) consists of veins without a preferred strike and dip...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28264063/acute-death-of-astrocytes-in-blast-exposed-rat-organotypic-hippocampal-slice-cultures
#15
Anna P Miller, Alok S Shah, Brandy V Aperi, Shekar N Kurpad, Brian D Stemper, Aleksandra Glavaski-Joksimovic
Blast traumatic brain injury (bTBI) affects civilians, soldiers, and veterans worldwide and presents significant health concerns. The mechanisms of neurodegeneration following bTBI remain elusive and current therapies are largely ineffective. It is important to better characterize blast-evoked cellular changes and underlying mechanisms in order to develop more effective therapies. In the present study, our group utilized rat organotypic hippocampal slice cultures (OHCs) as an in vitro system to model bTBI. OHCs were exposed to either 138 ± 22 kPa (low) or 273 ± 23 kPa (high) overpressures using an open-ended helium-driven shock tube, or were assigned to sham control group...
2017: PloS One
https://www.readbyqxmd.com/read/28184035/immediate-effects-of-angular-joint-mobilization-a-new-concept-of-joint-mobilization-on-pain-range-of-motion-and-disability-in-a-patient-with-shoulder-adhesive-capsulitis-a-case-report
#16
Younghoon Kim, GyuChang Lee
BACKGROUND Adhesive capsulitis is a common disabling condition, with reviews reporting up to 5.3% of the population being affected, the burden placed upon individuals and healthcare services may therefore be considered substantial. For recovering the normal extensibility of the capsule in individuals with adhesive capsulitis of the shoulder, passive stretching of the capsule through end-range mobilization has been suggested. Recently, the concept of joint mobilization into angular joint mobilization (AJM), which is rotational joint mobilization with joint axis shift, was proposed...
February 10, 2017: American Journal of Case Reports
https://www.readbyqxmd.com/read/28114174/case-report-lightning-induced-pneumomediastinum
#17
Ryan Blumenthal, Gert Saayman
We present the case of a 41-year-old woman who was fatally injured during a witnessed lightning strike event and in whom autopsy revealed the unusual keraunopathological finding of overt pneumomediastinum. The possible pathophysiological mechanism(s) of causation of this phenomenon are discussed, with specific reference also to the "Macklin" effect and the role of blast overpressures associated with lightning strike. It is suggested that the latter may lead to sudden alveolar rupture, with subsequent rapid tracking of air along bronchovascular sheaths in a centripetal manner toward the hilum of the lung and thus into the mediastinum...
June 2017: American Journal of Forensic Medicine and Pathology
https://www.readbyqxmd.com/read/28107370/neuronal-injury-and-glial-changes-are-hallmarks-of-open-field-blast-exposure-in-swine-frontal-lobe
#18
Srinivasu Kallakuri, Alok Desai, Ke Feng, Sharvani Tummala, Tal Saif, Chaoyang Chen, Liying Zhang, John M Cavanaugh, Albert I King
With the rapid increase in the number of blast induced traumatic brain injuries and associated neuropsychological consequences in veterans returning from the operations in Iraq and Afghanistan, the need to better understand the neuropathological sequelae following exposure to an open field blast exposure is still critical. Although a large body of experimental studies have attempted to address these pathological changes using shock tube models of blast injury, studies directed at understanding changes in a gyrencephalic brain exposed to a true open field blast are limited and thus forms the focus of this study...
2017: PloS One
https://www.readbyqxmd.com/read/28103428/aqueous-biphasic-systems-for-the-synthesis-of-formates-by-catalytic-co2-hydrogenation-integrated-reaction-and-catalyst-separation-for-co2-scrubbing-solutions
#19
Martin Scott, Beatriz Blas Molinos, Christian Westhues, Giancarlo Franciò, Walter Leitner
Aqueous biphasic systems were investigated for the production of formate-amine adducts by metal-catalyzed CO2 hydrogenation, including typical scrubbing solutions as feedstocks. Different hydrophobic organic solvents and ionic liquids could be employed as the stationary phase for cis-[Ru(dppm)2 Cl2 ] (dppm=bis-diphenylphosphinomethane) as prototypical catalyst without any modification or tagging of the complex. The amines were found to partition between the two phases depending on their structure, whereas the formate-amine adducts were nearly quantitatively extracted into the aqueous phase, providing a favorable phase behavior for the envisaged integrated reaction/separation sequence...
March 22, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28018003/refuge-alternatives-relief-valve-testing-and-design
#20
T J Lutz, P T Bissert, G T Homce, J A Yonkey
The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork...
October 2016: Mining Engineering
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