Satellite monitoring of sea surface pollution

The author has identified the following significant results. Image processing techniques developed are well adapted to the exploration and isolation of local areas which exhibit small temperature differences between themselves and their surroundings. In the worst case of imagery of small areal extent of sea surface having no coastal boundary in the area, there is yet no method of distinguishing unambiguously an oil spill from fog, cloud, the effect produced by shallow sediments, or the effects of naturally occuring thermal fronts. In the case of uniform slicks of liquid North Sea oil in still air, laboratory simulation experiments show that, for oil thicknesses in excess of 1 or 2 mm, there is, under equilibrium conditions, little dependence of oil surface temperature on the thickness of the oil layer. The surface temperature of oil is consistently higher than that of water, the difference being about 1 K at low values of relative humidity, but tending to increase as the relative humidity increases

Properties and Performance of a New Compact HF Aerial Design for Multi-Band Operation

This work is an extension to that of Telfer and Austin [1] in that here a balanced feed embodiment of an inwardly-inclined folded dual monopole aerial is presented and discussed in terms of its improved performance over the original configuration. This includes greater control of the stability of the far-field (FF) lobe pattern with operating frequency, and a considerably extended frequency range (3:1 ratio) over which Near Vertical Incidence Skywave (NVIS) propagation in the high frequency (HF) bands can be exploited. Furthermore, the FF lobe patterns at frequencies >2× the fundamental design frequency are such that advantage can be taken of conventional non-NVIS horizontal propagation at those frequencies using the same aerial. At the fundamental frequency, compactness of design and robustness of its NVIS FF pattern to orientation make the novel balanced aerial design a convenient replacement for a full-length low dipole in cluttered environments. The paper also presents a vehicle-mounted version for medium range operation within HF skip distances. Applications highlighted include stations for remote monitoring of environmental measurements in difficult or hostile terrain.

Satellite monitoring of sea surface pollution

There are no author-identified significant results in this report

A Novel Approach to Power Circuit Breaker Design for Replacement of SF6

This contribution explores the role of PTFE ablation in enhancing current interruption for various background gases in high voltage circuit breakers. An assessment of the current interruption capability has been made in terms of the arcing duration and the contact gap length at which critical arc extinction is achieved. These observations are supported by measurements of the magnitude of extinction and re-ignition voltage peaks. Most previous and other current experimental work on gas filled circuit breaker design follows conventional wisdom in investigating arcing behaviours at elevated gas pressures (usually up to 6 bar). But in this work we concentrate on the effects of using low gas pressures (less than 1 bar) in the presence of a close-fitting shield of ablatant polymer material (PTFE) that surrounds the electrode assembly of an experimental high power circuit breaker. We demonstrate that for several different gases, arc extinction capability compares well under these conditions with SF6, suggesting that SF6 could be replaced entirely in this novel system by more environmentally friendly gases. Moreover, the critical contact gap lengths at extinction are only slightly greater than when using SF6 at 6 bar. Weight loss measurements from the ablatant shield suggest that a chemical puffer action is the most likely mechanism for achieving the observed arc extinctions in this system

Managing aquaculture in multi-use freshwater bodies: the case of Jatiluhur reservoir

The pressure on scarce freshwater resources from intensifying human activity is rising across the globe. This study presents the case of Jatiluhur—Indonesia\u27s largest reservoir, where unregulated aquaculture expansion has contributed to environmental degradation and associated conflicts with other water-users. Aiming to identify a strategy to improve the sustainability of cage aquaculture within Jatiluhur reservoir and other freshwater bodies facing similar challenges, this study consisted of an initial analysis of time bound satellite images of the reservoir and a systematic survey of 112 aquaculture farms. The results revealed that, with more than 45 000 production units in 2020, more than half of which are placed outside government-approved aquaculture zones, the carrying capacity of the reservoir is exceeded. An analysis of the farm-level production practices, pertinent to environmental regulation, indicated the existence of three main production strategies, with significant differences in eutrophication potential among them that would lead to better articulated policy actions. A feed manufacturer-focused policy to reduce total phosphorus levels in formulated diets by more than half, but still within the optimal level for fish performance, would have the most impact. Enforcement of registration and removal of illegal production units supported by satellite-based monitoring of compliance are key recommendations to support intensive cage culture remaining an important economic activity

From Service to Experience: Understanding and Defining the Hospitality Business

Failure adequately to define or understand hospitality as a commercial phenomenon has created a fragmented academic environment and a schizophrenia in the industry that has the potential to limit its development as a global industry. This article suggests that, by redefining hospitality as behaviour and experience, a new perspective emerges that has exciting implications for the management of hospitality businesses. A framework to describe hospitality in the commercial domain is proposed. This framework suggests a focus on the host–guest relationship, generosity, theatre and performance, ‘lots of little surprises’, and the security of strangers – a focus that provides guests with experiences that are personal, memorable and add value to their lives

Characterization of the JWST Pathfinder Mirror Dynamics Using the Center of Curvature Optical Assembly (CoCOA)

The JWST (James Webb Space Telescope) Optical Telescope Element (OTE) consists of a 6.6 meter clear aperture, 18-segment primary mirror, all-reflective, three-mirror anastigmat operating at cryogenic temperatures. To verify performance of the primary mirror, a full aperture center of curvature optical null test is performed under cryogenic conditions in Chamber A at NASA Johnson Space Center using an instantaneous phase measuring interferometer. After phasing the mirrors during the JWST Pathfinder testing, the interferometer is utilized to characterize the mirror relative piston and tilt dynamics under different facility configurations. The correlation between the motions seen on detectors at the focal plane and the interferometer validates the use of the interferometer for dynamic investigations. The success of planned test hardware improvements will be characterized by the multi-wavelength interferometer (MWIF) at the Center of Curvature Optical Assembly (CoCOA)

Evaporative Mass Loss Measurement as a Quality Control Tool for Quality Assurance in the Manufacture of Inks Suitable for High Speed (≥60 m/min) Printing

In any manufacturing environment, it is always important to be able to embrace a culture of traceability of any non-conformed product. For the case of ink manufacture, operator confusion, leading to the mixing-up of solvents, or connecting the incorrect solvent drum to solvent lines, can lead to disastrous consequences that are not trivial for a quality control/quality assurance team to unravel. Accordingly, simple methods for assessing whether the correct solvents were added in the correct ratios to products empower this QA/QC requirement. In this paper, we examine the use of a trivial measurement of evaporative mass loss as a protocol for validating the conformance of manufactured ink to specification. Inspired by the transport-limit that occurs at ultramicroelectrodes in electrochemistry, we develop theory to analyse evaporation rate measurements, and illustrate how vaporisation at the liquid | gas interface is dominated by a diffusion anisotropy, owing to natural convection for organic solvents, manufactured resins and commercialised inks that have been used, inter alia, for the underground transport tickets in the cities of London and Paris. We further demonstrate that the use of incorrect solvents is readily seen through evaporation rate transients, thereby enabling this measurement for human factor mitigation during the ink manufacture process