2,751 research outputs found

    On the Beach and in the Bag: The Fate of Dieppe Casualties Left Behind

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    When the last Allied ships drew away from the beaches of Dieppe on 19 August 1942, they left behind over 2,700 of the 4,963 Canadians who had embarked on the raid: 807 men were dead, including four Royal Canadian Army Medical Corps [RCAMC] medical orderlies, and 1,946 (including four Canadian Medical Officers (MOs), a chaplain, and at least 11 RCAMC medical orderlies and 48 accredited stretcher-bearers) were abandoned to German captivity on the beaches and environs.1 As Lord Lovat wrote decades after the event, “the raid was an exceedingly bitter experience, learnt the hard way.”2 It is to the fate of these nearly two thousand men, and in particularly the 568 who had been wounded and then captured, that this article is devoted. Many of the survivors faced lengthy hospitalization and rehabilitation, frequently under the care of POW medical personnel rather than German doctors. The account of that medical treatment is one of the untold stories of the Dieppe raid

    Model Study of the Manifold to be Used as a Component of the Virginia Electric and Power Company, 1974 Extension of Yorktown Power Station

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    Introduction: This report describes the fabrication and laboratory testing of a 1/12 scale model of the 5 branch converging manifold to be installed as a component of the Virginia Electric and Power Company 1974 extension of the Yorktown power station. The design of the manifold (see Fig. 1) was supplied by Brown & Root, Inc. The geometry of Branch number 1 as shown on Fig. 1 was modified slightly from the original design after conferring with Browth & Root, Inc. in order to facilitate the fabrication of this branch of the model. In addition to the fabrication of the manifold model, facilities were constructed to carry out the testing of the model. These facilities consisted of: (1) a head box designed to force equal flow rates through all five inlet branches of the manifold (see Fig. 2), (2) five inlet pipes which convey the water from the five units in the head box to each of five branches, (3) a 20-foot long 14 inch inside diameter pipe which conveyed the discharge from the manifold, and (4) a discharge box with means for controlling the downstream head by means of two gates, one of which closes the discharge pipe and the other controls the water level in the box. The test facilities were located in the hydraulic laboratory of the Utah Water Research Laboratory taking the water supply from one of the 16 inch main supply lines and discharging the flow into a 3-foot wide channel in the floor of the hydraulic laboratory which conveys the water to the weighing tanks for accurate flow rate determinations. The photographs on Fig. 3 show the manifold model, the test facilities and their layout

    Gas-tight means zero defects - design considerations for thin-walled fluidic devices with overhangs by laser powder bed fusion

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    The industrial adoption of additive manufacturing (AM) technologies increased due to more applications and use cases demonstrating significant functional benefits. Additive manufacturing of thin-walled gas tight structures with complex shapes can fulfil requirements for a wide range of applications, such as process equipment for the chemical industry. The requirement to be gas-tight makes the manufacturing process very fault-sensitive as even a single open pore in the submicron range can lead to an impermissible leak of hazardous gases. Further, it has always been a challenge to make thin walls using Laser Powder Bed Fusion of Metals (PBF-LB/M). We explore the key design limit of inclined overhanging gas-tight thin walls made from 316l. A double pass scan strategy is presented to realize these structures along with guidelines to be followed when attempting to print these structures. The paper reports the common failure modes where leaks occur and lessons learned to successful design and printing of gas tight walls. The results show that fabrication of gas-tight walls is feasible even for a 30° inclination angle to the horizontal and wall thicknesses in the range of 200–300 µm. A case study shows the successful the application of the findings to the production of modular distillation devices

    Hydraulic Tests on Model of Manifold of the Pumps of The 1974 Extension of The Yorktown Power Station With All Combinations of One and Two Branches Taken Out of Operation

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    Introduction: A description of the fabrication of the manifold model and the design of the facilities constructed to test the model under various steady state flow conditions is given in the previous report. All tests included in the last report were with equal flows occurring in each of the five branches. Since the operation of the prototype manifold will necessitate that one, and possibly two pumps, be taken out of operations when the demand for cooling water is at a minimum, Browth & Root, Inc. requested taht the performance of the manifold model be determined under steady-state conditions with: (1) Equal flows through all combinations of four branches in operation, i.e. one of the five pumps taken out of operations and (2) Equal flows through all combinations of three branches in operations, i.e. all combinationf of two pumps taken out of operation. Analyses of the data thus collected is to be used to indicate which pump should be shut down first, and which two pumps should not be placed in operation for the very low flow rates. If the performance of the manifold is unsatisfactory with one or two pumps out of operation, th emodel tests should reveal this and suggest what redesign may be needed for the manifold to operate more satisfactorily

    Development and evaluation of the modiolar research array – multi-centre collaborative study in human temporal bones

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    OBJECTIVE: Multi-centre collaborative study to develop and refine the design of a prototype thin perimodiolar cochlear implant electrode array and to assess feasibility for use in human subjects. STUDY DESIGN: Multi-centre temporal bone insertion studies. MATERIALS AND METHODS: The modiolar research array (MRA) is a thin pre-curved electrode that is held straight for initial insertion with an external sheath rather than an internal stylet. Between November 2006 and February 2009, six iterations of electrode design were studied in 21 separate insertion studies in which 140 electrode insertions were performed in 85 human temporal bones by 12 surgeons. These studies aimed at addressing four fundamental questions related to the electrode concept, being: (1) Could a sheath result in additional intra-cochlear trauma? (2) Could a sheath accommodate variations in cochlea size and anatomies? (3) Could a sheath be inserted via the round window? and (4) Could a sheath be safely removed once the electrode had been inserted? These questions were investigated within these studies using a number of evaluation techniques, including X-ray and microfluoroscopy, acrylic fixation and temporal bone histologic sectioning, temporal bone microdissection of cochlear structures with electrode visualization, rotational tomography, and insertion force analysis. RESULTS: Frequent examples of electrode rotation and tip fold-over were demonstrated with the initial designs. This was typically caused by excessive curvature of the electrode tip, and also difficulty in handling of the electrode and sheath. The degree of tip curvature was progressively relaxed in subsequent versions with a corresponding reduction in the frequency of tip fold-over. Modifications to the sheath facilitated electrode insertion and sheath removal. Insertion studies with the final MRA design demonstrated minimal trauma, excellent perimodiolar placement, and very small electrode dimensions within scala tympani. Force measurements in temporal bones demonstrated negligible force on cochlear structures with angular insertion depths of between 390 and 450°. CONCLUSION: The MRA is a novel, very thin perimodiolar prototype electrode array that has been developed using a systematic collaborative approach. The different evaluation techniques employed by the investigators contributed to the early identification of issues and generation of solutions. Regarding the four fundamental questions related to the electrode concept, the studies demonstrated that (1) the sheath did not result in additional intra-cochlear trauma; (2) the sheath could accommodate variations in cochlea size and anatomies; (3) the sheath was more successfully inserted via a cochleostomy than via the round window; and (4) the sheath could be safely removed once the electrode had been inserted

    The Orbit of the Eclipsing X-ray Pulsar EXO 1722-363

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    With recent and archival Rossi X-Ray Timing Explorer (RXTE) X-ray measurements of the heavily obscured X-ray pulsar EXO 1722-363 (IGR J17252-3616), we carried out a pulse timing analysis to determine the orbital solution for the first time. The binary system is characterized by a_x sin(i) = 101 +/- 3 lt-s and P_orb = 9.7403 +/- 0.0004 days (90% confidence), with the precision of the orbital period being obtained by connecting datasets separated by more than 7 years (272 orbital cycles). The orbit is consistent with circular, and e < 0.19 at the 90% confidence level. The mass function is 11.7 +/- 1.2 M_sun and confirms that this source is a High Mass X-ray Binary (HMXB) system. The orbital period, along with the previously known ~414 s pulse period, places this system in the part of the Corbet diagram populated by supergiant wind accretors. Using previous eclipse time measurements by Corbet et al. and our orbital solution, combined with the assumption that the primary underfills its Roche lobe, we find i > 61 degrees at the 99% confidence level, the radius of the primary is between 21 R_sun and 37 R_sun, and its mass is less than about 22 M_sun. The acceptable range of radius and mass shows that the primary is probably a supergiant of spectral type B0I-B5I. Photometric measurements of its likely counterpart are consistent with the spectral type and luminosity if the distance to the system is between 5.3 kpc and 8.7 kpc. Spectral analysis of the pulsar as a function of orbital phase reveals an evolution of the hydrogen column density suggestive of dense filaments of gas in the downstream wake of the pulsar, with higher levels of absorption seen at orbital phases 0.5-1.0, as well as a variable Fe K_alpha line.Comment: Submitted to ApJ, 11 pages, 11 figure

    Calibration of the GLAST Burst Monitor detectors

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    The GLAST Burst Monitor (GBM) will augment the capabilities of GLAST for the detection of cosmic gamma-ray bursts by extending the energy range (20 MeV to > 300 GeV) of the Large Area Telescope (LAT) towards lower energies by 2 BGO-detectors (150 keV to 30 MeV) and 12 NaI(Tl) detectors (10 keV to 1 MeV). The physical detector response of the GBM instrument for GRBs is determined with the help of Monte Carlo simulations, which are supported and verified by on-ground calibration measurements, performed extensively with the individual detectors at the MPE in 2005. All flight and spare detectors were irradiated with calibrated radioactive sources in the laboratory (from 14 keV to 4.43 MeV). The energy/channel-relations, the dependences of energy resolution and effective areas on the energy and the angular responses were measured. Due to the low number of emission lines of radioactive sources below 100 keV, calibration measurements in the energy range from 10 keV to 60 keV were performed with the X-ray radiometry working group of the Physikalisch-Technische Bundesanstalt (PTB) at the BESSY synchrotron radiation facility, Berlin.Comment: 2 pages, 1 figure; to appear in the Proc. of the First Int. GLAST Symp. (Stanford, Feb. 5-8, 2007), eds. S.Ritz, P.F.Michelson, and C.Meegan, AIP Conf. Pro
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