2,911 research outputs found
Comparisons Between Modeling and Measured Performance of the BNL Linac
Quite good agreement has been achieved between computer modeling and actual
performance of the Brookhaven 200 MeV Linac. We will present comparisons
between calculated and measured performance for the beam transport through the
RFQ, the 6 meter transport from RFQ to the linac and meching and transport
through the linac.Comment: 3 page
A Super-Conducting Linac Driver for the HFBR
This paper reports on the feasibility study of a proton Super-Conducting
Linac (SCL) as a driver gor the High-Flux Breader Reactor (HFBR) at Brookhaven
National Laboratory (BNL). The Linac operates in Continuos Wave (CW) mode to
produce an average 10 MW of beam power. The Linac energy is 1.0 GeV. The
average proton beam intensity is 10 mA.Comment: 3 page
The relevance of point defects in studying silica-based materials from bulk to nanosystems
The macroscopic properties of silica can be modified by the presence of local microscopic modifications at the scale of the basic molecular units (point defects). Such defects can be generated during the production of glass, devices, or by the environments where the latter have to operate, impacting on the devices’ performance. For these reasons, the identification of defects, their generation processes, and the knowledge of their electrical and optical features are relevant for microelectronics and optoelectronics. The aim of this manuscript is to report some examples of how defects can be generated, how they can impact device performance, and how a defect species or a physical phenomenon that is a disadvantage in some fields can be used as an advantage in others
Fatigue Effects in Elastic Materials with Variational Damage Models: A Vanishing Viscosity Approach
We study the existence of quasistatic evolutions for a family of gradient damage models which take into account fatigue, that is the process of weakening in a material due to repeated applied loads. The main feature of these models is the fact that damage is favoured in regions where the cumulation of the elastic strain (or other relevant variables, depending on the model) is higher. To prove the existence of a quasistatic evolution, we follow a vanishing viscosity approach based on two steps: we first let the time step τ of the time discretisation and later the viscosity parameter ε go to zero. As τ→ 0 , we find ε-approximate viscous evolutions; then, as ε→ 0 , we find a rescaled approximate evolution satisfying an energy-dissipation balance
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Messaging, Marketing, and Identity: Content Analysis of Waterfowl Hunting Videos
Abstract
Media has been documented to significantly impact children and adolescents’ behavior, attitudes, cultural norms, identity development, and normative behaviors. We conducted a content analysis of three waterfowl hunting videos to determine what images and words were being conveyed to hunters, and a mail survey of Illinois waterfowl hunters to test how age may influence viewing of waterfowl hunting media. In particular, we hypothesized that: 1) age will influence whether hunters have watched waterfowl hunting media, and 2) age will influence how often hunters watch them. Overall, 82% of waterfowl hunters had watched waterfowl hunting media. Age influenced whether hunters, and how often hunters, had watched them; younger hunters were more likely to have watched the media and watched them significantly more often. Media watching also influenced hunters’ expectations, their identity as a waterfowl hunter, and their perception of the number of birds they harvest when compared to others. Results suggest that media influences waterfowl hunters’ expectations, identity, and behavior, all of which play an important role in how we will manage for waterfowl hunters in the future
The durability of carbon fiber/epoxy composites under hydrothermal ageing
Studies on fibre reinforced composites are now receiving greater attention. Industrial applications have been successful in areas like aerospace, automobile, marine, construction and sporting goods. The first generation of epoxy resins for use in carbon fibre composites are able to achieve optimized high stiffness modules and high heat resistance by a high crosslink density, reached through thermal curing. However, these formulations can be very toxic and brittle with low crack resistance, which was a major disadvantage for structural applications. In the last years the use of ionizing radiation as alternative to thermal curing has been proposed as an environmentally friendly process. Furthermore, in order to enhance toughness mechanical requirements for their applications, the formulation generally consists of blends of epoxy resins and engineering thermoplastics. In terms of durability (service life and reliability), in these materials it depends on different environmental conditions (temperature, moisture, etc.), and it is very important to know how their properties are modified after the exposure to different temperature and moisture absorption cycles. In this work carbon fibre composites produced by ionizing radiation induced curing of the epoxy based matrices have been subjected to thermal and moisture absorption ageing and the influence of these treatments on the thermal and mechanical properties has been investigated through dynamic mechanical thermal analysis and mechanical fracture toughness tests
Structure of the FeBTC Metal\u2013Organic Framework: A Model Based on the Local Environment Study
The local environment of iron in FeBTC, a metal organic framework commercially known as Basolite F300, is investigated combining XANES and EXAFS studies of the iron K-edge. The building block of the FeBTC can be described as an iron acetate moiety. Dehydration induces a change in the coordination of the first shell while preserving the network. We propose that the local structure around Fe atoms does not undergo a rearrangement, thus, leading to the formation of an open site. The analysis conveys that the FeBTC is a disordered network of locally ordered blocks
Atlantis II : cruise 102 : moored and shipboard surface meteorological measurements during JASIN 1978
During cruise 102 of the R/V Atlantis-II in the Joint Air-Sea Interaction
Project (JASIN), surface meteorological data were gathered by Woods Hole
Oceanographic Institution personnel from two moored buoys and from the ship.
One buoy (JASIN W2/WHOI 651) carried a Vector Averaging Wind Recorder
(VAWR) and a Vector Measuring Wind Recorder (VMWR); these instruments provided
18 days of intercomparison data and 38 days of meteorological data from 30 July
to 6 September 1978. The other buoy (JASIN H2) carried a VMWR and gave 25
total days of data from 16 July to 10 August, and from 26 August to
1 September.
A PET computer, hardwired to sensors positioned on the ship, displayed
data that were logged during both legs of the cruise. Manual data were
gathered by the science watches.
This report describes the PET system, and displays and compares all the
data. VAWR hourly meteorological data are listed for the 38 day period.
Scientific interpretation of these data, such as calculations of heat
fluxes, will be published separately.Prepared for the National Science Foundation under
Grants OCE77-25803 and OCE76-80174, and for the Office
of Naval Research under Contract N00014-76-C-0197;
NR 083-400 to the Woods Hole Oceanographic Institution
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