12,707 research outputs found

    TNT equivalency of M10 propellant

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

    On the feasibility of a tripler uprade for LHC

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    The design of high-field dipoles has been optimized using a block-coil geometry. The optimization includes stress management and flux plate suppression of multipoles from snap-back. The design has been extended to higher field by devising a hybrid coil geometry containing inner windings of Bi-2212 and outer windings of Nb3_{3}Sn. A 24 Tesla dual dipole using this design offers the possibility of an LHC tripler. Issues of fabrication technology and synchrotron radiation control are discussed. There is no obvious upper limit to the field that could be attained for the dipoles of future hadron colliders

    Blood lactate clearance during active recovery after an intense running bout depends on the intensity of the active recovery

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    High-intensity exercise training contributes to the production and accumulation of blood lactate, which is cleared by active recovery. However, there is no commonly agreed intensity or mode for clearing accumulated blood lactate. We studied clearance of accumulated blood lactate during recovery at various exercise intensities at or below the lactate threshold after high-intensity interval runs that prompted lactate accumulation. Ten males repeated 5-min running bouts at 90% of maximal oxygen uptake ([Vdot]O2max), which increased blood lactate concentration from 1.0 ± 0.1 to 3.9 ± 0.3 mmol · l-1. This was followed by recovery exercises ranging from 0 to 100% of lactate threshold. Repeated blood lactate measurements showed faster clearance of lactate during active versus passive recovery, and that the decrease in lactate was more rapid during higher (60-100% of lactate threshold) than lower (0-40% of lactate threshold) (P < 0.05) intensities. The more detailed curve and rate analyses showed that active recovery at 80-100% of lactate threshold had shorter time constants for 67% lactate clearance and higher peak clearance rates than 40% of lactate threshold or passive recovery (P < 0.05). Finally, examination of self-regulated intensities showed enhanced lactate clearance during higher versus lower intensities, further validating the intensity dependence of clearance of accumulated blood lactate. Therefore, active recovery after strenuous exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner. Maximum clearance occurred at active recovery close to the lactate threshold

    Projections for future radiocarbon content in dissolved inorganic carbon in hardwater lakes: a retrospective approach

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    Inland water bodies contain significant amounts of carbon in the form of dissolved inorganic carbon (DIC) derived from a mixture of modern atmospheric and pre-aged sources, which needs to be considered in radiocarbon-based dating and natural isotope tracer studies. While reservoir effects in hardwater lakes are generally considered to be constant through time, a comparison of recent and historical DI14C data from 2013 and 1969 for Lake Constance reveals that this is not a valid assumption. We hypothesize that changes in atmospheric carbon contributions to lake water DIC have taken place due to anthropogenically forced eutrophication in the 20th century. A return to more oligotrophic conditions in the lake led to reoxygenation and enhanced terrigenous organic matter remineralization, contributing to lake water DIC. Such comparisons using DI14C measurements from different points in time enable nonlinear changes in lake water DIC source and signature to be disentangled from concurrent anthropogenically induced changes in atmospheric 14C. In the future, coeval changes in lake dynamics due to climate change are expected to further perturb these balances. Depending on the scenario, Lake Constance DI14C is projected to decrease from the 2013 measured value of 0.856 Fm to 0.54–0.62 Fm by the end of the century

    Painful toxins acting at TRPV1

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    Many plant and animal toxins cause aversive behaviors in animals due to their pungent or unpleasant taste or because they cause other unpleasant senstations like pain. This article reviews the current state of knowledge of toxins that act at the TRPV1 ion channel, which is expressed in primary sensory neurons, is activated by multiple painful stimuli and is thought to be a key pain sensor and integrator. The recent finding that painful peptide 'vanillotoxin' components of tarantula toxin activate the TRPV1 ion channel to cause pain led us to survey what is known about toxins that act at this receptor. Toxins from plants, spiders and jellyfish are considered. Where possible, structural information about sites of interaction is considered in relation to toxin-binding sites on the Kv ion channel, for which more structural information exists. We discuss a developing model where toxin agonists such as resiniferatoxin and vanillotoxins are proposed to interact with a region of TRPV1 that is homologous to the 'voltage sensor' in the Kv1.2 ion channel, to open the channel and activate primary sensory nerves, causing pain

    The Creative Studio Practice of Contemporary Dance Music Sampling Composers

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    This paper seeks to investigate some of the considerations that inform and help to determine the creative studio practice of contemporary sampling composers. Collaborative writing and production, specifically the co-opted collaboration implicit in using samples, will be assessed to consider those aspects of the production process which the participants consider to be authorial. These considerations include acts of listening, selecting and editing. In examining these matters this paper places emphasis on how sampling composers actively constrain their options in order to promote a creative relationship with their musical material. Techniques such as, firstly, traditional sample manipulation, secondly, the use of a sample as an initial building block for a composition from which the sample is then removed and, finally, live performance in the studio which is subsequently cut up and treated as a sample, will be discussed. Case studies, in the form of semi-structured interviews with sampling composers, will be drawn upon to assess approaches to and views about these forms of studio composition
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