4,826 research outputs found
Zebra battery technologies for all electric smart car
This paper describes the operational behaviour and advantages of the high temperature, sodium nickel chloride (Zebra) battery, for use in all electric urban (city) vehicles. It is shown that an equivalent parallel electrical circuit can be employed to accurately simulate the electrochemical behaviour inherent in the most recent generation of Zebra cells. The experimental procedure is outlined and summary attributes of the investigation validated by both simulation studies, and experimentally, via measurements from a prototype battery module intended for use in an all electric smart ca
Los pingüinos de la región de Magellanes
The Magellan region, including the Falkland Islands, is one of the world´s most important areas for seabirds, and especially penguins. World-wide there are 17 species of penguin; 7 of these regularly breed around the coastal waters of South America, and 5 within the Magellan region. These are the King Penguin (Aptenodytes patagonicus), Gentoo Penguin (Pygoscelis papua), Rockhopper Penguin (Eudyptes c. chrysocome), Macaroni Penguin (Eudyptes chrysolophus) and Magellanic Penguin (Spheniscus magellanicus). During the last five years, a review of the breeding populations of penguins within the Magellan region was conducted. This work included population censuses of all the surface breeding species throughout the Falkland Islands and southern South America. The results of this work are presented, along with other cited information, to provide a summary of the current knowledge of penguin populations within the Magellan region.La región de Magallanes, incluyendo las Islas Falkland, es un área muy importante para las aves marinas del mundo. Hay 17 especies de pingüinos; 7 crían en América del Sur y 5 crían en la región de Magallanes. Se trata de los Pingüino Rey (Aptenodytes patagonicus), Pingüino Papúa (Pygoscelis papua), Pingüino de Penacho Amarillo (Eudyptes c. chrysocome), Pingüino Macaroni (Eudyptes chrysolophus) y Pingüino de Magallanes (Spheniscus magellanicus). Durante los últimos 5 años investigamos las poblaciones de los pingüinos en la región de Magallanes. Esta investigación incluyó registros de todas las especies que crían sobre la tierra en las Islas Falkland y en el extremo meridional de América del Sur. Presentamos nuestros resultados con información de otra literatura citada para proporcionar un resumen del conocimiento sobre las poblaciones de los pingüinos en la región de Magallanes
Research notes: Cytology of soybean haploid progeny
Haploids are being isolated annually among individuals obtained from polyembryonic seeds associated with the North Carolina male sterile (ms1). The haploids are being used to obtain aneuploids. In 1976 and 1977, 7,206 and 15,530 seeds, respectively, were obtained from male sterile plants (ms1 North Carolina) representing Maturity Groups I- V
Amplification and generation of ultra-intense twisted laser pulses via stimulated Raman scattering
Twisted Laguerre-Gaussian lasers, with orbital angular momentum and
characterised by doughnut shaped intensity profiles, provide a transformative
set of tools and research directions in a growing range of fields and
applications, from super-resolution microcopy and ultra-fast optical
communications to quantum computing and astrophysics. The impact of twisted
light is widening as recent numerical calculations provided solutions to
long-standing challenges in plasma-based acceleration by allowing for high
gradient positron acceleration. The production of ultrahigh intensity twisted
laser pulses could then also have a broad influence on relativistic
laser-matter interactions. Here we show theoretically and with ab-initio
three-dimensional particle-in-cell simulations, that stimulated Raman
backscattering can generate and amplify twisted lasers to Petawatt intensities
in plasmas. This work may open new research directions in non-linear optics and
high energy density science, compact plasma based accelerators and light
sources.Comment: 18 pages, 4 figures, 1 tabl
Estimating Hourly Solar Radiation for One-Axis Tracking Focusing Collectors
Performance simulations of focusing parabolic collectors are hampered by a limited amount of useful insolation data. Hourly values of total radiation on a horizontal surface are the most common data available from the National Oceanographic & Atmospheric Administration. This paper develops a method to convert this total horizontal radiation to direct radiation on the surface of the tracking collector
Internal Stress in a Model Elasto-Plastic Fluid
Plastic materials can carry memory of past mechanical treatment in the form
of internal stress. We introduce a natural definition of the vorticity of
internal stress in a simple two-dimensional model of elasto-plastic fluids,
which generates the internal stress. We demonstrate how the internal stress is
induced under external loading, and how the presence of the internal stress
modifies the plastic behavior.Comment: 4 pages, 3 figure
Using Flow Specifications of Parameterized Cache Coherence Protocols for Verifying Deadlock Freedom
We consider the problem of verifying deadlock freedom for symmetric cache
coherence protocols. In particular, we focus on a specific form of deadlock
which is useful for the cache coherence protocol domain and consistent with the
internal definition of deadlock in the Murphi model checker: we refer to this
deadlock as a system- wide deadlock (s-deadlock). In s-deadlock, the entire
system gets blocked and is unable to make any transition. Cache coherence
protocols consist of N symmetric cache agents, where N is an unbounded
parameter; thus the verification of s-deadlock freedom is naturally a
parameterized verification problem. Parametrized verification techniques work
by using sound abstractions to reduce the unbounded model to a bounded model.
Efficient abstractions which work well for industrial scale protocols typically
bound the model by replacing the state of most of the agents by an abstract
environment, while keeping just one or two agents as is. However, leveraging
such efficient abstractions becomes a challenge for s-deadlock: a violation of
s-deadlock is a state in which the transitions of all of the unbounded number
of agents cannot occur and so a simple abstraction like the one above will not
preserve this violation. In this work we address this challenge by presenting a
technique which leverages high-level information about the protocols, in the
form of message sequence dia- grams referred to as flows, for constructing
invariants that are collectively stronger than s-deadlock. Efficient
abstractions can be constructed to verify these invariants. We successfully
verify the German and Flash protocols using our technique
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