820 resultados para Composite tapered beams


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Contient : S. Ambrosius, De officiis ; Fragments d'un antiphonaire

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Contient : Boetius, De institutione musica ; De divinis officiis, libri I-III ; Homeliae [fragments] ; Robertus de Sancto Remigio, Historia Hierosolimitana ; Homeliae super evangelia

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The composite includes photos of: Richard Woodruff (1822-1887) brother of Samuel Woodruff, son of William Woodruff. He married Cornelia McCrumb. His son-in- law was Samuel Zimmerman of the bank. Richard was a director of the Niagara Suspension Bridge. Joseph Woodruff (1820-1886) son of William Woodruff. He married Julia Claus. He was the Sherriff of Lincoln County and one of the incorporators of the Zimmerman Bank. Samuel DeVeaux Woodruff (1819-1904) who was the son of William Woodruff. He married Jane Caroline Sanderson (1827-1912) William Woodruff (1793-1860) who was the son of Ezekiel Woodruff who was born on July 29, 1763 and moved to the Niagara area from Litchfield Connecticut. He died in Niagara on Nov. 26, 1836. Henry Counter Woodruff (1833-1916) was the 7th child of William Woodruff. He married Emma Eloise Osgood (1835-1925) Dr. William Woodruff (1830-1908) of London, Ont. was the son of William Woodruff. Helena Woodruff (1828-1892) was the daughter of William Woodruff. She married Joseph Patterson Boomer. Julia Woodruff (1825-1870) was the sister of Samuel DeVeaux Woodruff and the daughter of William Woodruff.

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Composite of the Woodruff Family of St. Davids, Upper Canada. This composite contains 6 4 ½ cm x 4 cm black and white photographs which include: Samuel DeVeaux Woodruff (1819-1904) [the birth and death dates listed on this composite are 1827-1912, but these are actually his wife’s dates] son of William Woodruff. Joseph Woodruff (1820-1882) [1820-1886] son of William Woodruff. Helena Woodruff (1828-1892) daughter of William Woodruff. Julia Woodruff (1825-1870) daughter of William Woodruff. Dr. William Woodruff (1830-1908) son of William Woodruff. Margaret Clements [Clement] Woodruff (1794-1882) wife of William Woodruff

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Tesis (Maestría en Ciencias con Orientación en Ingeniería Estructural) UANL, 2013.

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Tesis (Doctor en Ingeniería de Materiales) UANL, 2014.

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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Depuis quelques années, il y a un intérêt de la communauté en dosimétrie d'actualiser les protocoles de dosimétrie des faisceaux larges tels que le TG-51 (AAPM) et le TRS-398 (IAEA) aux champs non standard qui requièrent un facteur de correction additionnel. Or, ces facteurs de correction sont difficiles à déterminer précisément dans un temps acceptable. Pour les petits champs, ces facteurs augmentent rapidement avec la taille de champ tandis que pour les champs d'IMRT, les incertitudes de positionnement du détecteur rendent une correction cas par cas impraticable. Dans cette étude, un critère théorique basé sur la fonction de réponse dosimétrique des détecteurs est développé pour déterminer dans quelles situations les dosimètres peuvent être utilisés sans correction. Les réponses de quatre chambres à ionisation, d'une chambre liquide, d'un détecteur au diamant, d'une diode, d'un détecteur à l'alanine et d'un détecteur à scintillation sont caractérisées à 6 MV et 25 MV. Plusieurs stratégies sont également suggérées pour diminuer/éliminer les facteurs de correction telles que de rapporter la dose absorbée à un volume et de modifier les matériaux non sensibles du détecteur pour pallier l'effet de densité massique. Une nouvelle méthode de compensation de la densité basée sur une fonction de perturbation est présentée. Finalement, les résultats démontrent que le détecteur à scintillation peut mesurer les champs non standard utilisés en clinique avec une correction inférieure à 1%.

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On line isotope separation techniques (ISOL) for production of ion beams of short-lived radionuclides require fast separation of nuclear reaction products from irradiated target materials followed by a transfer into an ion source. As a first step in this transport chain the release of nuclear reaction products from refractory metals has been studied systematically and will be reviewed. High-energy protons (500 - 1000 MeV) produce a large number of radionuclides in irradiated materials via the nuclear reactions spallation, fission and fragmentation. Foils and powders of Re, W, Ta, Hf, Mo, Nb, Zr, Y, Ti and C were irradiated with protons (600 - 1000 MeV) at the Dubna synchrocyclotron, the CERN synchrocyclotron and at the CERN PS-booster to produce different nuclear reaction products. The main topic of the paper is the determination of diffusion coefficients of the nuclear reaction products in the target matrix, data evaluation and a systematic interpretation of the data. The influence of the ionic radius of the diffusing species and the lattice type of the host material used as matrix or target on the diffusion will be evaluated from these systematics. Special attention was directed to the release of group I, II and III-elements. Arrhenius plots lead to activation energies of the diffusion process.

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The effect of various processing parameters, such as nip gap, friction ratio and roll temperature, on the tensile properties of short Kevlar aramid fibre-thermoplastic polyurethane composite has been investigated and the tensile and tear fracture surfaces have been characterised using a scanning electron microscope. A nip gap of 0.45 mm, a friction ratio of 1.15 and a roll temperature of 62°C was found to give optimum mechanical properties. Scanning electron microscopy study revealed a higher extent of fibre orientation in the milling direction in the above condition.

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Tear and wear properties of short kevlar fiber, thermoplastic polcurethane (TPU) composite with respect to fiber loading-and fiber onentation has been studied and the fracture surfaces were examined under scanning electron microscope (SEM). Tear strength first decreased up to 20 phr fiber loading and then gradually increased with increasing fiber loading. Anisotropy in tear strength was evident beyond a fiber loading of 20 phr. Tear fracture surface of unfilled TPU showed sinusoidal folding characteristics of high strength matrix. At low fiber loading the tear failure was mainly due to fibermatrix failure whereas at higher fiber loading the failure occurred by fiber breakage. Abrasion loss shows a continuous rise with increasing fiber loading, the loss in the transverse orientation of fibers being higher than that in the longitudinal orientation. The abraded surface showed lone cracks and ridges parallel to the direction of abrasion indicating an abrasive wear mechanism. In the presence of fber the abrasion loss was mainly due to fiber low.

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The self adhesion behaviour of thermoplastic polyurethane (TPU) in itself and its composite with short Kevlar fibre with respect to contact time, temperature, pressure, and fibre loading has been studied. The adhesion strength showed two linear increments of different slopes with respect to the square root of time: with temperature and pressure of contact, the adhesion strength was improved. The maximum strength was obtained with 20 phr of short fibre in only one of the mating substrates in the peel test sample. The duration for wetting and diffusion was shifted to longer time intervals with fibres loaded in both the substrates.

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The flammability of short Kevlar aramide fiber-thermoplastic polyurethane (TPU) has been investigated with respect to fiber loading and various flame retardant additives such as halogen containing polymers, antimony oxide/chlorine donor combination, zinc borate, and aluminum hydroxide. Smoke generation was reduced drastically, while the oxygen index was reduced marginally in the presence of short fibers. The best improvement in the oxygen index was obtained with antimony oxide/chlorinated paraffin wax combination, in the weight ratio 1:6. A 70 phr loading of aluminum hydroxide improved LOI and reduced smoke generation.

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The thermal degradation of short nylon-6 fiber reinforced acrylonitrile butadiene rubber (NBR) composites with and without epoxy-based bonding agent has been studied by thermogravimetric analysis (TGA). It was found that the onset of degradation shifted from 330.5 to 336.1°C in the presence of short nylon fiber, the optimum fiber loading being 20 phr. The maximum rate of degradation of the composites was lower than that of the unfilled rubber compound, and it decreased with increase in fiber concentration. The presence of epoxy resin-based bonding agent in the virgin elastomer and the composites improved the thermal stability. Results of kinetic studies showed that the degradation of NBR and the short nylon fiber reinforced composites followed first-order kinetics.

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The thermal properties of short Nylon-6 fiber-reinforced Styrene butadiene rubber (SBR) composites were studied by Thermogravimetric Analysis (TGA). The effect of epoxy-based bonding agent on thermal degradation of the gum and the composites was also studied. The thermal stability of the SBR was enhanced in the presence of Nylon-6 fibers and the stability of the composites increased in the presence of bonding agent. The epoxy resin did not significantly change the thermal stability of SBR gum vulcanizate. Results of kinetic studies showed that the degradation of SBR and the short nylon fiber-reinforced composites with and without bonding agents followed first-order kinetics.