Towards Recyclable Insulation Materials for High Voltage Cables

The preferred material for modern extruded high voltage transmission cables is cross-linked polyethylene (XLPE). This material has excellent thermo-mechanical and dielectric properties, however it is not easily recycled at end of use, raising questions as to its long term sustainability [1]. Therefore research work at Southampton has sought to identify suitable recyclable alternatives to XLPE. Such candidate materials need to have low temperature flexibility and high temperature mechanical stability combined with a sufficiently high electrical breakdown strength

Finding a closest point in a lattice of Voronoi's first kind

We show that for those lattices of Voronoi's first kind with known obtuse superbasis, a closest lattice point can be computed in $O(n^4)$ operations where $n$ is the dimension of the lattice. To achieve this a series of relevant lattice vectors that converges to a closest lattice point is found. We show that the series converges after at most $n$ terms. Each vector in the series can be efficiently computed in $O(n^3)$ operations using an algorithm to compute a minimum cut in an undirected flow network

Lidar measurements of thermal structure

Rayleigh backscatter observations at 532 nm and 355 nm of relative atmospheric density above Aberystwyth on a total of 93 nights between Dec. 1982 and Feb. 1985 were used to derive the height variation of temperature in the upper stratosphere and mesosphere. Preliminary results for height up to about 25 km were also obtained from observations of Raman backscattering from nitrogen molecules. Comparisons were carried out for stratospheric heights with satellite borne measurements; good agreement was found between equivalent black body temperatures derived from the lidar observations and those obtained from nadir measurements in three channels of the stratosphere sounder units on NOAA satellites; the lidar based atmospheric temperatures have shown general agreement with but a greater degree of structure than the limb sounding measurements obtained using the SAMS experiment on the NOAA-7 satellite. In summer, stratospheric and mesospheric temperatures showed a smooth height variation similar to that of the CIRA model atmosphere. In contrast, the winter data showed a great variability with height, and marked temperature changes both from night to night and within a given night

Observations of stratospheric aerosols associated with the El Chichon eruption

Lidar observations of aerosols were carried out at Aberystwyth between Nov. 1982 and Dec. 1985 using a frequency doubled and frequency tripled Nd/Yag laser and a receiver incorporating a 1 m diameter in a Newtonian telescope configuration. In analyses of the experimental data attention is paid to the magnitude of the coefficient relating extinction and backscatter, the choice being related to the possible presence of aerosols in the upper troposphere and the atmospheric densities employed in the normalisation procedure. The aerosol loading showed marked day to day changes in early months and an overall decay was apparent only after April 1983, this decay being consistent with an e sup -1 time of about 7 months. The general decay was accompanied by a lowering of the layer but layers of aerosols were shown intermittently at heights above the main layer in winter months. The height variations of photon counts corrected for range, or of aerosol backscatter ratio, showed clear signatures of the tropopause. A strong correlation was found between the heights of the tropopause identified from the lidar measurements and from radiosonde-borne temperature measurements. A notable feature of the observations is the appearance of very sharp height gradients of backscatter ratio which seem to be produced by differential advection

Electrical Treeing in Silicone Rubber

Electrical treeing has been widely studied in a range of polymeric materials. In these investigations, the morphology and PD patterns associated with the growth of electrical trees in a model transparent silicone rubber were investigated using a new system recently developed at Southampton. With increasing voltage the trees became more complex in appearance but nevertheless grow more rapidly. As the tree evolves the PD pattern becomes more intense which may provide a method of monitoring the extent of treeing in opaque samples. Raman studies indicate that treeing and breakdown channels are hollow, carbonaceous entities, a finding consistent with other studies

The use of morphological description in neighbourhood planning: form-based assessment of physical character and design rules

Despite ongoing efforts to encourage the use of urban morphology tools into current practice, uptake remains limited. Shortcomings are largely attributed to time and resource intensive methods of historical settlement transformation study. However, developments in quantitative morphological approaches offer new possibilities for efficiency and easier adoption of research tools in practice. This paper proposes the use of typo-morphology methods to inform the adoption of form-based design guidance in neighbourhood master plans. The aim of the study is to develop a comprehensive yet flexible method for form-based character assessment (FBCA) of residential streets. The resulting FBCA classification identifies streets where compliance with form-based design rules could be tightened. The FBCA method is empirically tested in the context of the local neighbourhood plan for Radlett, Hertfordshire in the United Kingdom, offering reflections from practice on the usefulness and limitations of the method

Non-Medical Prescription Pain Reliever Use as a Risk Factor for Suicidal Ideation

Research has shown a positive association between depression and non-medical prescription pain reliever use. Given the connection of depression to suicidality, the current research question evaluates non-medical prescription pain reliever use as an indicator of suicidal thought. Using the 2011 National Survey on Drug Use and Health, our analysis found that non-medical use of pain relievers increased the odds for suicidal ideation (O.R. = 2.36). Future research is needed to understand the mechanisms underlying this link. Potential mechanisms include substance induced depression and non-medical pain reliever use in the context of conditions such as chronic pain

Population Status of the Southern Cavefish, Typhlichthys subterraneus in Arkansas

We summarize the results of our study on the status of the southern cavefish (Typhlichthys subterraneus) in Arkansas. Its presence in the state represents the western-southern limits of its distribution. Four localities have been confirmed that contain individuals of this species: Richardson Cave (Fulton County), Alexander Cave/Clark Spring (Stone County), Ennis Cave (Stone County), and Lake Norfork (Baxter County). A fifth locality has been cited as a well in Randolph County, but because the exact location is unknown, its presence has not been confirmed. A number of unconfirmed localities for “cavefishes” in the region has not been included in this report. Populations of this species in Arkansas seem to be small (less than 100 individuals) which is common among populations of hypogean amblyopsids elsewhere. All the confirmed localities are in areas either under controlled access by the private owners or by the federal government. No immediate threat to these populations was found by either overcollecting or other anthropogenic causes. Yet long-term monitoring of the recharge zones is recommended