36,202 research outputs found
Glasgow time signals
From 1859 to 1864, both visual and audio one o’clock time signals operated in Glasgow. Although the University carried a remit to provide the city’s time, following convoluted processes of establishment, a local chronometer-maker operated a time ball for 4 years. Towards the end of the period, time guns were triggered by telegraph from the Royal Observatory Edinburgh. Both exercises caused aggravation for the University. For the ball, the Professor of Astronomy, John Pringle Nichol, failed to convince the City Council that the “drop” control should originate from the University’s Observatory. For the guns, Robert Grant, the newly appointed Astronomy Chair holder, was aggrieved by the Astronomer Royal for Scotland, Piazzi Smyth, appearing to operate above his station. Rather than having only a once per day reference, both projects were abandoned as the University laid a dedicated telegraph cable from its observatory to control many public clocks and additional clocks with large sweep fingers indicating exact time to the second
Coupled Ocean Atmosphere Processes and European Climate (COAPEC): improved understanding of the coupled climate system
COAPEC (http://coapec.nerc.ac.uk/) is a five-year Directed Science Programme funded by the Natural Environment Research Council (NERC). COAPEC is providing advances in understanding the mechanisms by which the ocean and atmosphere interact, how these processes are represented in state-of-the-art numerical climate models and how they determine the predictability of the climate system over seasonal-decadal timescales. Processes studied include the generation and propagation of salinity and heat anomalies in the North Atlantic, the influence of the thermohaline circulation and the role of storm tracks on European Climate. The influence of remote processes, including ocean-atmosphere coupling in tropical Atlantic warm events and Southern Ocean circulation are also being investigated.
As part of the programme, new coupled models are being developed, including: a coupled hybrid isopycnic coordinate model; fast models for multi-ensemble runs to investigate model parameters space, using both high performance machines and spare home PC resources; a QG model to investigate high resolution ocean processes in coupled systems and validated ice models for coupled modelling. Underpinning research into improving the observational datasets, such as the SOC flux climatology, and into the influence of sea-ice observations in General Circulation Models is also being carried out as part of the programme.
To place these advances into a socially relevant context, COAPEC is also investigating the methods for using, and economic benefits of, climate forecasts at seasonal timescales for the UK health sector and the UK energy industry
Epitaxial gallium arsenide wafers
The preparation of GaAs epitaxial layers by a vapor transport process using AsCl3, Ga and H2 was pursued to provide epitaxial wafers suitable for the fabrication of transferred electron oscillators and amplifiers operating in the subcritical region. Both n-n(+) structures, and n(++)-n-n(+) sandwich structures were grown using n(+) (Si-doped) GaAs substrates. Process variables such as the input AsCl3 concentration, gallium temperature, and substrate temperature and temperature gradient and their effects on properties are presented and discussed
Integrated airframe propulsion control
Perturbation equations which describe flight dynamics and engine operation about a given operating point are combined to form an integrated aircraft/propulsion system model. Included in the model are the dependence of aerodynamic coefficients upon atmospheric variables along with the dependence of engine variables upon flight condition and inlet performance. An off-design engine performance model is used to identify interaction parameters in the model. Inclusion of subsystem interaction effects introduces coupling between flight and propulsion variables. To analyze interaction effects on control, consideration is first given to control requirements for separate flight and engine models. For the separate airframe model, feedback control provides substantial improvement in short period damping. For the integrated system, feedback control compensates for the coupling present in the model and provides good overall system stability. However, this feedback control law involves many non-zero gains. Analysis of suboptimal control strategies indicates that performance of the closed loop integrated system can be maintained with a feedback matrix in which the number of non-zero gains is small relative to the number of components in the feedback matrix
Studies of Autumn calving suckler cows, bulls at pasture and winter grazing
End of project reportMost beef and dairy cows are spring calving leading to distinct seasonality of supply. Calving
a proportion of the beef herd in the autumn would lead to a more uniform annual supply of
cattle for slaughter and potentially increase the proportion of grazed grass in the diet of the
suckler progeny. Autumn calving sucklers also facilitate the use of AI, which should enhance
the product quality.
This project aimed to address the technical aspects of autumn calving sucklers, which differ
from those of spring calvers. The currently available international energy models were
evaluated for autumn calving lactating suckler cows using the type of cow typically found in
Irish suckler herds (Experiment 1). The winter accommodation of the suckler cow and calf
unit and its impact on cow reproductive performance was evaluated (Experiment 2).
The final part of the project evolved into component studies to determine the effect of
supplementary feed on the performance of grazing bulls (Experiment 3), and the
consequences of weanling cattle grazing pasture in winter as an alternative to housing them in winter (Experiments 4 to 7)
Development of material specifications and qualifications of polymeric materials for the jpl spacecraft materials guide book. iii- polyfluorocarbon films special report no. 3
Outgassing studies of polyfluorocarbon films - investigation of polymers as spacecraft construction material
The incidence and position of melanocytic nevi for the purposes of forensic image comparison
Expert witness opinion based on the comparison of images has been accepted by UK courts as admissible evidence in relation to issues of identity. Within images of the hand are a multiplicity of anatomical features of different aetiology, incidence and distribution patterns and this includes melanocytic nevi, referred to more colloquially as moles and/or birthmarks. The hand is not a common place for these isolated features to develop and so their presence in this anatomical region has the potential to be useful for issues of identity. The results of this study show that approximately 9 % of individuals in a sample of 476 hands, displayed at least one nevus on the back of their hand and, contrary to the literature, the incidence was found to be greater in females (15 % of female cohort) than males (7 % of male cohort). Almost a third of all nevi identified on the dorsum of the hand were abnormal or dysplastic. The most frequent location for these aggregations of melanocytes was in the central region of the dorsum of the hand or at the base of the index finger. The relevance of nevi identified in the image of a perpetrator’s hand and also on that of a suspect/accused is discussed in relation to the issue of whether the images have originated from the same individual
Development of material specifications and qualifications of polymeric materials for the jpl spacecraft materials guidebook. 1- epoxide adhesives special report no. 1
Outgassing characteristics of nine epoxide adhesives, and thermal vacuum performance for adhesives teste
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