3,215 research outputs found

    A Public Spirit: George H. Atkinson’s Written Legacy

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    George Henry Atkinson (1819-89) was a son of New England who arrived in the Oregon Territory in 1848, sent by the American Home Missionary Society. Although his commission from the Society specified that his work was to be ecclesiastical and educational, he took an approach to that assignment which went well beyond his mandate. Well-informed and energetic, he made an impact on the Congregational churches of the Northwest, while using that base of action to spread his influence far beyond the churches that were his primary area of responsibility. He believed that a successful future for his adopted region required productive, intelligent, moral communities. This broad perspective led him to assume—and maintain for four decades—public leadership in subjects as diverse and significant as railroads, prisons, public and private schools, Native American relationships, agriculture, engineering, commerce, and meteorology. He left an impressive written legacy, in personal correspondence and in print. This volume contains a number of Atkinson’s longer writings. Most were published in the state’s leading newspaper, the Oregonian, although several appeared in other publications or reports. Two were included in the records of the State Legislature and two were submitted to the Centennial Exposition in Philadelphia in 1876. Taken together, his writings tell us much about the man George Henry Atkinson, and about the times and places where he implemented his vision.https://commons.pacificu.edu/beetree/1000/thumbnail.jp

    Resorption thermal transformer generator design

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    This work takes an empirical and evidence-based approach in the development of a resorption thermal transformer. It presents the initial modelling conducted to understand key performance parameters (coefficient of performance and specific mean power) before discussing a preliminary design. Experimental results from large temperature jump and isosteric heating tests have identified the importance of heat transfer in ammonia-salt systems. Both the heat transfer resistance between the salt composite adsorbent and the tube side wall, and the heat transfer from the heat transfer fluid to the tube side wall are key to realising resorption systems. The successful performance of a laboratory-scale prototype will depend on the reduction in these heat transfer resistances, and improvements may be key in future prototype machines. A sorption reactor is sized and presented, which can be scaled for length depending on the desired power output. The reactor design presented was derived using data on reaction kinetics constants and heat of reaction for calcium chloride reacting with ammonia that were obtained experimentally. The data enabled accurate modelling to realise an optimised design of a reactor, focusing on key performance indicators such as the coefficient of performance (COP) and the system power density. This design presents a basis for a demonstrator that can be used to collect and publish dynamic data and to calculate a real COP for resorption system

    Influence of Fecal Sample Storage on Bacterial Community Diversity

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    Previous studies have identified a correlation, either positive or negative, between specific stool bacteria strains and certain autoimmune diseases. These conflicting data may relate to sample collection. The aim of this work was to evaluate the influence of the collection parameters of time and temperature on bacterial community composition. Samples were taken from healthy children and immediately divided in 5 sub-samples. One sample was frozen immediately at -80°C, while the other aliquots were frozen 12, 24, 48, and 72h later DNA extracted from each sample was used to amplify the 16S rRNA with barcoded primers. The amplified products were pooled and partial 16S rRNA sequences were obtained by pyrosequencing. Person-to-person variability in community diversity was high. A list of those taxa that comprise at least 1% of the community was made for each individual. None of these were present in high numbers in all individuals. The Bacteroides were present in the highest abundance in three of four subjects. A total of 23,701 16S rRNA sequences were obtained with an average of 1,185 reads per sample with an average length of 200 bases. Although pyrosequencing of amplified 16S rRNA identified changes in community composition over time (~10%), little diversity change was observed at 12 hours (3.06%) with gradual changes occurring after 24 (8.61%), 48 (9.72%), and 72 h (10.14%), post collection

    Design and manufacture of a proof-of-concept resorption heat pump using ammonia-salt chemisorption reactions

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    Using the Large Temperature Jump (LTJ) experimental technique, alongside a review of the literature, sodium bromide (NaBr) and manganese chloride (MnCl2) have been identified as a suitable working pair with ammonia refrigerant for a proof-of-concept resorption heat pump system. LTJ tests using a tube-side and shell-side unit cell reactor (sorption heat exchanger), show that the experimentally obtained equilibrium lines for adsorption and desorption of sodium bromide are: ΔHADS = 30,102.5 J/mol; ΔSADS = 207.7 J/(mol·K); ΔHDES = 30,216.4 J/mol; and ΔSDES = 206.8 J/(mol·K). Using a semi-empirical model, the NaBr composite salt (salt impregnated in expanded natural graphite (ENG)) has been characterised for use as a low temperature salt in a resorption heat pump, with manganese chloride as the high-temperature salt. The model constants, A and n, for adsorption are 1 and 3, and for desorption are 5 and 4 respectively for NaBr. Manganese chloride data has been previously reported (Hinmers et al., 2022). With an appreciation of the reaction dynamics and behaviour of the NaBr and MnCl2 composite salts, a proof-of-concept resorption system has been designed and manufactured. The reactor design, alongside the overall experimental rig design (including data acquisition system) is reported. Initial filling and flushing tests show the success of the data acquisition and control system, and thus the overall suitability of the proof of-concept system for investigations into the coupled nature of ammonia salt reactions for a resorption heat pump application

    Design of Experiments for Screening

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    The aim of this paper is to review methods of designing screening experiments, ranging from designs originally developed for physical experiments to those especially tailored to experiments on numerical models. The strengths and weaknesses of the various designs for screening variables in numerical models are discussed. First, classes of factorial designs for experiments to estimate main effects and interactions through a linear statistical model are described, specifically regular and nonregular fractional factorial designs, supersaturated designs and systematic fractional replicate designs. Generic issues of aliasing, bias and cancellation of factorial effects are discussed. Second, group screening experiments are considered including factorial group screening and sequential bifurcation. Third, random sampling plans are discussed including Latin hypercube sampling and sampling plans to estimate elementary effects. Fourth, a variety of modelling methods commonly employed with screening designs are briefly described. Finally, a novel study demonstrates six screening methods on two frequently-used exemplars, and their performances are compared

    Community participation for malaria elimination in tafea province, vanuatu: part ii. social and cultural aspects of treatment-seeking behaviour

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    Background: Early diagnosis and prompt effective case management are important components of any malaria elimination strategy. Tafea Province, Vanuatu has a rich history of traditional practices and beliefs, which have been integrated with missionary efforts and the introduction of modern constructions of health. Gaining a detailed knowledge of community perceptions of malarial symptomatology and treatment-seeking behaviours is essential in guiding effective community participation strategies for malaria control and elimination
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