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881.
Implementation of IEEE-1588 timing and synchronization for ATCA control and data acquisition systems
Miguel Correia Jorge Sousa Álvaro Combo António P. Rodrigues Bernardo B. Carvalho António J.N. Batista Bruno Gonçalves Carlos M.B.A. Correia Carlos A.F. Varandas 《Fusion Engineering and Design》2012,87(12):2178-2181
Control and data acquisition (C&DA) systems for Fusion experiments are required to provide accurate timing and synchronization (T&S) signals to all of its components. IPFN adopted PICMG's Advanced Telecommunications Computing Architecture (ATCA) industry standard to develop C&DA instrumentation. ATCA was chosen not only for its high throughput characteristics but also for its high availability (HA) features which become of greater importance in steady-state operation scenarios. However, the specified ATCA clock and synchronization interface may be too limited for the timing and synchronization needs in advanced Physics experiments. Upcoming specification extensions, developed by the “xTCA for Physics” workgroups, will contemplate, among others, a complementary timing specification, developed by the PICMG xTCA for Physics IO, Timing and Synchronization Technical Committee. The IEEE-1588 Precision Time Protocol (PTP) over Ethernet is one of the protocols, proposed by the Committee, aiming for precise synchronization of clocks in measurement and control systems, based on low jitter and slave-to-slave skew criteria.The paper presents an implementation of IEEE-1588 over Ethernet, in an ATCA hardware platform. The ATCA hardware consists of an Advanced Mezzanine Card (AMC) quad-carrier front board with PCI Express switching. IEEE-1588 is to be implemented on a Virtex-6 FPGA. Ethernet connectivity with the remote master clock is located on the rear transition module (RTM). The generated synchronized clock and absolute time in IRIG-B format are distributed to all systems endpoints by a cross-point switch which is also implemented on the FPGA. 相似文献
882.
Batista Dias Lebrun Le Flour Inglebert 《Fatigue & Fracture of Engineering Materials & Structures》2000,23(3):217-228
Helical gears from an automotive gearbox, previously subjected to the surface treatments of carbo‐nitriding and shot‐peening, were submitted to contact fatigue tests. The X‐ray diffraction technique was used to characterize the evolution of different mechanical and metallurgical parameters as a function of gear damage. Particular attention was paid to residual stress relief. A numerical model was developed to predict residual stress relaxation and estimate the most likely localization of contact fatigue crack initiation. The stress–strain laws of the surface‐treated layers were determined by means of two separate experimental methods, based on locally measured parameters. The Dang Van multiaxial fatigue criterion was used to analyse the failure of the gears, taking into account the effects of friction and roughness. 相似文献
883.
Jin ZL Tada A Sugimoto N Sato K Masuda A Yamagata K Yamazaki T Tanamoto K 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2006,47(4):167-172
Urushi wax is a natural gum base used as a food additive. In order to evaluate the quality of urushi wax as a food additive and to obtain information useful for setting official standards, we investigated the constituents and their concentrations in urushi wax, using the same sample as scheduled for toxicity testing. After methanolysis of urushi wax, the composition of fatty acids was analyzed by GC/MS. The results indicated that the main fatty acids were palmitic acid, oleic acid and stearic acid. LC/MS analysis of urushi wax provided molecular-related ions of the main constituents. The main constituents were identified as triglycerides, namely glyceryl tripalmitate (30.7%), glyceryl dipalmitate monooleate (21.2%), glyceryl dioleate monopalmitate (2.1%), glyceryl monooleate monopalmitate monostearate (2.6%), glyceryl dipalmitate monostearate (5.6%), glyceryl distearate monopalmitate (1.4%). Glyceryl dipalmitate monooleate isomers differing in the binding sites of each constituent fatty acid could be separately determined by LC/MS/MS. 相似文献
884.
J. D. Lamim H. C. P de Oliveira A. C. Batista R. S. Guimarães M. Filgueira 《Materialwissenschaft und Werkstofftechnik》2010,41(4):198-201
Nanosized WC, and binders Co, Ti and Ti‐Co, are used to process hardmetals. Titanium (Ti) was proposed to reduce and even replace the Co in these composites, verifying the effectiveness of the new binders. Samples of nanosized WC with 10 wt% Co, 9 wt% WC 1 wt% Ti – Co, WC‐10 wt% Ti were cold compacted at 200 MPa and sintered at 1500°C during 1 hour under vacuum of 10–2 mbar for the processing of hardmetal were performed. The structural characterization by X‐ray diffraction and microstructure by scanning electron microscopy (SEM) and EDS microanalysis of the sintered material. We observed the presence of the W2C phase in the sintered samples, and Co3W phases in the samples with Co content and a good distribution of binder phase, leading to formation of small “pool” of Co and Ti and small porosity and well distributed. It was proved that using Ti as binder phase, the neta phase formation was avoided. 相似文献
885.
Wescley Tiago Batista de Sousa Lincoln Brum de Leite?Gusm?o?Pinheiro Alcione Roberto Jurelo Rosangela Menegotto Costa Pedro Rodrigues Gerson Kniphoff da Cruz Fabio Teixeira Dias 《Journal of Superconductivity and Novel Magnetism》2010,23(7):1307-1312
Fluctuations in the electrical conductivity of polycrystalline Ho1−x
Pr
x
Ba2Cu3O7−δ
superconductors were investigated with Ho contents from x=0.01 up to 0.10. Samples were prepared by the standard solid-state reaction technique. The method of analysis is based on
the determination of the quantity
cs-1=-\fracddTlnDs\chi_{\sigma}^{-1}=-\frac{d}{dT}\ln\Delta\sigma, where Δσ=σ−σ
R
is the fluctuation conductivity. The results show that the resistive transition proceeds in two stages as seen by the temperature
derivative of the resistivity near T
C
. In the normal phase, Gaussian and critical fluctuation conductivity regimes were identified. The pairing transition splitting,
associated with Pr doping and related to the occurrence of a phase separation, as observed in studies with other rare earth
elements, was not clearly observed. On approaching the zero-resistance state, our results show a power-law behavior that corresponds
to a phase transition from a paracoherent to a coherent state of the granular array. This behavior was not affected by Pr
doping. 相似文献
886.
N. Tada 《International Journal of Fracture》1992,57(3):199-220
Approximate solutions of the electrical potential difference for semi-elliptical surface cracks in semi-infinite and finite bodies are presented. The solution for the finite cracked body is analytically derived based on the theory of a Superposition Method (SM), which is developed and used by the author to examine the face effect on the potential difference. The approximate solutions derived in this paper give accurate potential difference and the applicability of electrical potential technique is greatly extended by these new solutions. 相似文献
887.
Böhlke JK Sturchio NC Gu B Horita J Brown GM Jackson WA Batista J Hatzinger PB 《Analytical chemistry》2005,77(23):7838-7842
Perchlorate has been detected recently in a variety of soils, waters, plants, and food products at levels that may be detrimental to human health. These discoveries have generated considerable interest in perchlorate source identification. In this study, comprehensive stable isotope analyses (37Cl/35Cl and 18O/17O/16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. In addition, isotopic analyses of perchlorate extracted from groundwater and surface water demonstrate the feasibility of identifying perchlorate sources in contaminated environments on the basis of this technique. Both natural and synthetic sources of perchlorate have been identified in water samples from some perchlorate occurrences in the United States by the isotopic method. 相似文献
888.
K Tamada M Harada K Abe T Li H Tada Y Onoe K Nomoto 《Canadian Metallurgical Quarterly》1998,46(3):128-136
Tissue processed at a constant temperature of 45 C including the use of paraffin wax with a melting point of 45 C displays staining characteristics that are sometimes reversed from those associated with the more usual processing schedules and wax with a melting point of 58-60 C. Staining with acid dyes, particularly in trichrome methods, are most susceptible to these changes. We suggest that this is directly related to dye molecular size and to differences in the tissue structure resulting from the heat to which the tissues were exposed. 相似文献
889.
M Kawanishi S Nagasawa T Ohta K Yamaguchi Y Tada T Kuroiwa 《Canadian Metallurgical Quarterly》1996,18(6):564-566
Hemodynamic changes following unilateral vertebral artery (VA) occlusion were investigated in a rat model. The left carotid artery was resected and anastomosed to the right side in an end-to-side fashion to create a half-ring bypass. The distal side of the bypass was regarded as a union of VAs. Changes in the geometry, histology and hemodynamics in the union were investigated after the recipient artery was ligated. Intimal thickening was most prominently observed in the recipient arterial segment distal to the ligation site, where the lumen was obliterated. However, the portion of the lumen within 2.6 +/- 0.6 (mean +/- s.d.) mm, a distance of 2.9 +/- 0.6 times the internal diameter from the union, was not obliterated. The angle of the union was positively related to the length of this residual lumen. The results of this study explain some of the pathogenesis in unsuccessful aneurysmal thrombosis or brain stem infarction after therapeutic unilateral VA occlusion. 相似文献
890.