8,234 research outputs found
Finding the way: improving access to the collections of the Royal Scottish Geographical Society
This case study describes and discusses the ‘Images for All’ project at the Royal Scottish Geographical Society and lessons learned from it. The background to the project and collections held is described. The case study focuses on the development of the project website, the digitisation of 100 images from the collection and the nature of project management in a small scale project. The paper finds that there are many potential challenges faced by project managers working in small voluntary organisations, but these can be overcome
Time dependence of current-voltage measurements of c-axis quasiparticle conductivity in 2212-BSCCO mesa structures
We report four-point IV measurements of the c-axis conductivity of mesa
structures of 2212-BSCCO, using a system with sub-microsecond resolution along
with multi-level pulses. These allow a test to be made for the presence of
nonequilibrium effects. Our results suggest simple heating alone is important
in measurements of this kind.Comment: to appear in proceedings of LT23; submitted to Physica
Underground measurements on secondary cosmic rays
Measurements made at the Poatina cosmic ray station (41.8 S 149.9 E, 347 m.w.e.) from August 1983 to July 1984 are summarized. The cosmic ray primary particles responsible for events detected at the station have a median primary energy of 1.2 TeV. The motivation for part of this work came from the reported detection of narrow angle anisotropies in the arrival direction of cosmic rays
Thermal fluctuations in moderately damped Josephson junctions: Multiple escape and retrapping, switching- and return-current distributions and hysteresis
A crossover at a temperature T* in the temperature dependence of the width s
of the distribution of switching currents of moderately damped Josephson
junctions has been reported in a number of recent publications, with positive
ds/dT and IV characteristics associated with underdamped behaviour for lower
temperatures T<T*, and negative ds/dT and IV characteristics resembling
overdamped behaviour for higher temperatures T>T*. We have investigated in
detail the behaviour of Josephson junctions around the temperature T* by using
Monte Carlo simulations including retrapping from the running state into the
supercurrent state as given by the model of Ben-Jacob et al. We develop
discussion of the important role of multiple escape and retrapping events in
the moderate-damping regime, in particular considering the behaviour in the
region close to T*. We show that the behaviour is more fully understood by
considering two crossover temperatures, and that the shape of the distribution
and s(T) around T*, as well as at lower T<T*, are largely determined by the
shape of the conventional thermally activated switching distribution. We show
that the characteristic temperatures T* are not unique for a particular
Josephson junction, but have some dependence on the ramp rate of the applied
bias current. We also consider hysteresis in moderately damped Josephson
junctions and discuss the less commonly measured distribution of return
currents for a decreasing current ramp. We find that some hysteresis should be
expected to persist above T* and we highlight the importance, even well below
T*, of accounting properly for thermal fluctuations when determining the
damping parameter Q.Comment: Accepted for publication in PR
European user trial of paging by satellite
British Telecom conceived the idea of adapting their existing paging service, together with the use of existing terrestrial pagers, to yield a one way data (i.e., paging) satellite service to mobiles. The user trial of paging by satellites was successful. It demonstrated that services could be provided over a wide geographical area to low priced terminals. Many lessons were learned in unexpected areas. These include the need for extensive liaison with all users involved, especially the drivers, to ensure they understood the potential benefits. There was a significant desire for a return acknowledgement channel or even a return data channel. Above all there is a need to ensure that the equipment can be taken across European borders and legitimately used in all European countries. The next step in a marketing assessment would be to consider the impact of two way data messaging such as INMARSAT-C
The multidriver: A reliable multicast service using the Xpress Transfer Protocol
A reliable multicast facility extends traditional point-to-point virtual circuit reliability to one-to-many communication. Such services can provide more efficient use of network resources, a powerful distributed name binding capability, and reduced latency in multidestination message delivery. These benefits will be especially valuable in real-time environments where reliable multicast can enable new applications and increase the availability and the reliability of data and services. We present a unique multicast service that exploits features in the next-generation, real-time transfer layer protocol, the Xpress Transfer Protocol (XTP). In its reliable mode, the service offers error, flow, and rate-controlled multidestination delivery of arbitrary-sized messages, with provision for the coordination of reliable reverse channels. Performance measurements on a single-segment Proteon ProNET-4 4 Mbps 802.5 token ring with heterogeneous nodes are discussed
Microscopic Alterations in Endocrine Glands and Other Organs of Rats Fed the Hepatic Carcinogen p-Dimethylaminoazobenzene
It was the purpose of this investigation to determine whether the feeding of DAB, in addition to inducing liver tumors, alters the microscopic structure of the endocrine system. In addition, a study was made of certain adrenal cortical hormones as possible modifiers of the carcinogenic effects of DAB
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