1,123 research outputs found
Dynamic Hardness Tester and Cure Meter
Get PDFThe Shore hardness tester is used extensively throughout industry to determine the static modulus of materials. The new apparatus described here extends the capability of an indentor-type tester into the dynamic regime, and provides a measurement of the dynamic shear or Young's modulus and loss factor as a function of frequency. The instrument, model and data of typical rubber samples are given and compared to other dynamic measurements
Interference of diffraction and transition radiation and its application as a beam divergence diagnostic
Get PDFWe have observed the interference of optical diffraction radiation (ODR) and
optical transition radiation (OTR) produced by the interaction of a
relativistic electron beam with a micromesh foil and a mirror. The production
of forward directed ODR from electrons passing through the holes and wires of
the mesh and their separate interactions with backward OTR from the mirror are
analyzed with the help of a simulation code. By careful choice of the micromesh
properties, mesh-mirror spacing, observation wavelength and filter band pass,
the interference of the ODR produced from the unperturbed electrons passing
through the open spaces of the mesh and OTR from the mirror are observable
above a broad incoherent background from interaction of the heavily scattered
electrons passing through the mesh wires. These interferences (ODTRI) are
sensitive to the beam divergence and can be used to directly diagnose this
parameter. We compare experimental divergence values obtained using ODTRI,
conventional OTRI, for the case when front foil scattering is negligible, and
computed values obtained from transport code calculations and multiple screen
beam size measurements. We obtain good agreement in all cases.Comment: 40 pages 18 Figures. accepted for publication in PRSTA
Alianza bíblica y regla religiosa. (Estudio histórico-salvífico de las Constituciones de la Compañía de Jesús)
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Metacestodes of elasmobranch tapeworms in octopus vulgaris (Mollusca, cephalopoda) from central mediterranean—SEM and molecular data
Get PDFCephalopods are intermediate/paratenic hosts in the life cycle of elasmobranch tapeworms, nevertheless most records of infection in this group of mollusks are outdated and fragmentary. The present work aimed to investigate the cestode fauna of the common octopus Octopus vulgaris from the Tyrrhenian Sea (Central Mediterranean). The parasitic stages were characterized by light and Scanning Electron Microscopy (SEM) and sequencing of 28S rDNA. Three cestode taxa were identified to the genus level: the onchoproteocephalidean Acanthobothrium sp. (prevalence 28%), the “tetraphyllidean” Anthobothrium sp. (prevalence 13%) and the trypanorhynch Nybelinia sp. (prevalence 3%). The remarkable prevalence observed for gastrointestinal cestodes highlight a possible important role of O. vulgaris in the transmission of elasmobranch tapeworms, particularly Onchoproteocephalideans. Furthermore, the present work provides, for the first time, detailed morphological (SEM) and molecular support to confirm the occurrence of Anthobothrium sp. in cephalopod hosts. In order to gain higher taxonomic resolution for the identified taxa, we stress the need to collect further morphological and molecular data of adult cestodes infecting their elasmobranch definitive hosts
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