Optimizing the performance of thermionic devices using energy filtering

Conventional thermionic power generators and refrigerators utilize a barrier in the direction of transport to selectively transmit high-energy electrons. Here we show that the energy spectrum of electrons transmitted in this way is not optimal, and we derive the ideal energy spectrum for operation in the maximum power regime. By using suitable energy filters, such as resonances in quantum dots, the power of thermionic devices can, in principle, be improved by an order of magnitude.Comment: 3 pages, 2 figure

Sprayable birefringent coating enables strain measurements on large surfaces

Birefringent coating for strain measurements on large surfaces contains constituents that can be premixed and sprayed as a single component with conventional paint spray equipment. Elevated temperatures are not required for spraying or curing of the coating material which has long pot life

Home Drying of Foods

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Social Sensing of Floods in the UK

"Social sensing" is a form of crowd-sourcing that involves systematic analysis of digital communications to detect real-world events. Here we consider the use of social sensing for observing natural hazards. In particular, we present a case study that uses data from a popular social media platform (Twitter) to detect and locate flood events in the UK. In order to improve data quality we apply a number of filters (timezone, simple text filters and a naive Bayes `relevance' filter) to the data. We then use place names in the user profile and message text to infer the location of the tweets. These two steps remove most of the irrelevant tweets and yield orders of magnitude more located tweets than we have by relying on geo-tagged data. We demonstrate that high resolution social sensing of floods is feasible and we can produce high-quality historical and real-time maps of floods using Twitter.Comment: 24 pages, 6 figure

A new comparison between solid-state thermionics and thermoelectrics

It is shown that equations for electrical current in solid-state thermionic and thermoelectric devices converge for devices with a width equal to the mean free path of electrons, yielding a common expression for intensive electronic efficiency in the two types of devices. This result is used to demonstrate that the materials parameters for thermionic and thermoelectric devices are equal, rather than differing by a multiplicative factor as previously thought

High altitude Himalayan climate inferred from glacial ice flux

Glaciological processes are modeled to investigate precipitation patterns and the resulting mass flux of snow and ice across Himalayan topography. Our model tracks the accumulation and ablation of snow and ice and the transport of snow and ice across the topography by glacier motion. We investigate high elevation precipitation on the Annapurna Massif by comparing the existing ice cover with model-simulated glaciers produced by a suite of different precipitation scenarios. Our results suggest that precipitation reaches a maximum level well below the elevation of the highest peaks. Further, essentially no snow accumulates on the topography above an elevation of 6200–6300 m. Hence, the upper 1000+ m of the massif is a high elevation desert with little flux of snow and ice. Active glaciers are limited to a band of intermediate elevations where a maximum of about 60% of the landscape is covered by moving ice

Mental health institutionalisation in a small Caribbean country: patient factors contributing to long term hospitalisation

RESUMO: As instituições psiquiátricas evoluíram na sua forma de funcionar nos últimos 2000 anos. Os serviços modernos de saúde mental mudaram de um modelo institucional para modelos baseados na comunidade. Este estudo procurou avaliar os fatores relacionados com o paciente que podem contribuir para internamentos prolongados. Estas pessoas institucionalizadas diferem de algumas formas das pessoas com doença mental que não foram institucionalizadas e, portanto, é vital abordar estas preocupações no processo de alta. Estes fatores incluem a gravidade da doença, habilidades sociais e apoio, fatores relacionados com a doença, como a adesão ao tratamento e o “insight”, e o apoio fornecido pela instituição para facilitar a recuperação e a autossuficiência. Os pacientes institucionalizados sofreram predominantemente de doenças psicóticas, foram internados involuntariamente na admissão inicial, apresentaram um funcionamento deficiente e tomaram vários medicamentos psicotrópicos. As avaliações da equipe mostraram preocupações em relação à adesão à medicação e aos sintomas residuais. Apesar de metade dos pacientes revelarem insatisfação com a enfermaria, surpreendentemente, em geral, não estavam insatisfeitos com os profissionais e os outros pacientes.. Comorbilidade com uma segunda doença mental ou doença médica foi observada na coorte examinada. Em pacientes institucionalizados, o modelo de recuperação, visto como uma filosofia orientadora, pode aumentar a probabilidade de alta. Este modelo foca-se na esperança e na resiliência na presença de doenças em curso. Os programas de saúde mental nas instituições devem primeiro reorientar as atitudes da equipe para o empoderamento do paciente, fornecer recursos para a reabilitação e incentivar o envolvimento e a conexão da comunidade.ABSTRACT: Psychiatric institutions have evolved in function over the last 2000 years. Modern mental health services have moved away from institutional care to community-based models. This study sought to evaluate the patient related factors which may contribute to long-stay hospitalisation. These institutionalised persons differ in some ways from persons with mental illness who have not been institutionalised, and therefore it is vital to address these concerns in the discharge process. These factors include severity of illness, social skills and support, illness related factors such as compliance with treatment and insight, and the support provided by the institution to facilitate recovery and self-sufficiency. Institutionalised patients suffered predominantly from psychotic illnesses, were involuntarily detained in hospital at initial admission, showed moderate function on assessment, and were prescribed multiple psychotropic medications. Staff ratings reflected concerns regarding compliance with medication and residual symptoms. Although half of patients interviewed were dissatisfied with the ward, surprisingly patients were not generally dissatisfied with the staff or other patients. Comorbidity with a second mental illness or medical illness was noted in the cohort examined. In institutionalised patients the recovery model as a guiding philosophy may enhance the likelihood for discharge. This focusses on hope and resilience in the presence of ongoing illness. Mental health programs in institutions must first reorient attitudes of the staff towards patient empowerment, provide resources for rehabilitation and encourage community involvement and connectedness