82 research outputs found

    Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

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    High temperature AlInP X-ray spectrometers

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    Two custom-made Al0.52In0.48P p+-i-n+ mesa photodiodes with different diameters (217 ”m ± 15 ”m and 409 ”m ± 28 ”m) and i layer thicknesses of 6 ”m have been electrically characterised over the temperature range 0 °C to 100 °C. Each photodiode was then investigated as a high-temperature-tolerant photon counting X-ray detector by connecting it to a custom-made low-noise charge-sensitive preamplifier and illuminating it with an 55Fe radioisotope X-ray source (Mn Kα = 5.9 keV; Mn KÎČ = 6.49 keV). At 100 °C, the best energy resolutions (full width at half maximum at 5.9 keV) achieved using the 217 ”m ± 15 ”m diameter photodiode and the 409 ”m ±28 ”m diameter photodiode were 1.31 keV ± 0.04 keV and 1.64 keV ±0.08 keV, respectively. Noise analysis of the system is presented. The dielectric dissipation factor of Al0.52In0.48P was estimated as a function of temperature, up to 100 °C. The results show the performance of the thickest Al0.52In0.48P X-ray detectors so far reported at high temperature. The work has relevance for the development of novel space science instrumentation for use in hot space environments and extreme terrestrial applications

    Integrated motor drives: state of the art and future trends

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    With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented

    Commercial Rabbit Raising

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    Excerpts from the report Introduction: The recommendations in this bulletin are based largely on studies at the U.S. Rabbit Experiment Station formerly maintained at Fontana, Calif., by the Sheep and Fur Animal Research Branch, Animal Science Research Division, Agricultural Research Service. At this station, improved methods were developed for producing rabbits for meat, fur, and wool of fine quality, for insuring sanitary surroundings, and for preventing outbreaks of parasitic and other diseases. This handbook is being issued to help county agricultural agents, State colleges of agriculture, and the U.S. Department of Agriculture answer the many thousands of requests received each year from commercial and professional rabbit producers for information about rabbits

    Commercial rabbit raising /

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    Simple circuit model of SiC pin diode composed by using experimental electrical characteristics

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    Does the prosperity of a country play a role in COVID-19 outcomes?

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    Objective: This study aims to clarify the association between prosperity and the coronavirus disease (COVID-19) outcomes and its impact on the future management of pandemics. Methods: This is an observational study using information from 2 online registries. The numbers of infected individuals and deaths and the prosperity rank of each country were obtained from worldometer.info and the Legatum Institute’s Prosperity Index, respectively. Results: There is a combination of countries with high and low prosperity on the list of COVID-19-infected countries. The risk of the virus pandemic seems to be more extensive in countries with high prosperity. A Spearman’s rho test confirmed a significant correlation between prosperity, the number of COVID-19 cases, and the number of deaths at the 99% level. Conclusion: New emerging pandemics affect all nations. In order to increase the likelihood of successfully managing future events, it is important to consider preexisting health security, valid population-based management approaches, medical decision-making, communication, continuous assessment, triage, treatment, early and complete physical distancing strategies, and logistics. These elements cannot be taught on-site and on occasion. There is a need for innovative and regular educational activities for all stakeholders committed to safeguarding our future defense systems concerning diagnostic, protection, treatment, and rehabilitation in pandemics, as well as other emergencies

    Applied machine vision of plants: a review with implications for field deployment in automated farming operations

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    Automated visual assessment of plant condition, specifically foliage wilting, reflectance and growth parameters, using machine vision has potential use as input for real-time variable-rate irrigation and fertigation systems in precision agriculture. This paper reviews the research literature for both outdoor and indoor applications of machine vision of plants, which reveals that different environments necessitate varying levels of complexity in both apparatus and nature of plant measurement which can be achieved. Deployment of systems to the field environment in precision agriculture applications presents the challenge of overcoming image variation caused by the diurnal and seasonal variation of sunlight. From the literature reviewed, it is argued that augmenting a monocular RGB vision system with additional sensing techniques potentially reduces image analysis complexity while enhancing system robustness to environmental variables. Therefore, machine vision systems with a foundation in optical and lighting design may potentially expedite the transition from laboratory and research prototype to robust field tool
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