Stirling cycle cryogenic cooler

A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling

Phosphorus Immobilization in Poultry Litter and Litter-amended soils with Aluminum, Calcium and Iron amendments

Arkansas produces approximately one billion broilers each year. Phosphorous (P) runoff from fields receiving poultry litter is believed to be one of the primary factors affecting water quality in Northwest Arkansas. Poultry litter contains approximately 20 g P kg-1, of which about 2 g P kg-1 is water soluble. Soils that have received repeated heavy applications of litter may have water soluble P contents of as high as 10 mg P Kg-1 soil. The objective of this study was to determine if soluble P levels could be reduced in poultry litter and litter-amended soils with Al,Ca, and/or Fe amendments. Poultry litter was amended with alum, sodium aluminate, quick lime, slaked lime, calcitic limestone, dolomitic limestone, gypsum, ferrous chloride, ferric chloride, ferrous sulfate and ferric sulfate, and incubated in the dark at 25°C for one week. Three soils which had been excessively fertilized with poultry litter were amended with alum, ferrous sulfate, calcitic limestone, gypsum and slaked lime and incubated for 4 weeks at 25 °C. In the litter studies, the Ca treatments were tested with and without CaF2 additions in an attempt to precipitate fluorapatite. At the end of the incubation period, the litter and soils were extracted with deionized water and soluble reactive P (SRP) was determined. SRP levels in the poultry litter were reduced from over 2,000 mg P kg-1 litter to less than 1 mg P kg-1 litter with the addition of alum, quick lime, slaked lime, ferrous chloride, ferric chloride, ferrous sulfate and ferric sulfate under favorable pH conditions. S.RP levels in the soils were reduced from approximately 5 mg P Kg-1 soil to less than 0.05 mg P Kg-1 soil with the addition of alum and ferrous sulfate under favorable pH conditions. Gypsum and sodium aluminate reduced SRP levels in litter by 50 to 60 percent while calcitic and dolomitic limestone were even less effective. In soils, the Ca amendments were less effective than the Al and Fe amendments, although slaked lime was effective at high pH. The results of these studies suggest that treating litter and excessively fertilized soils with some of these compounds, particularly alum, could significantly reduce the amount of SRP in runoff from littered pastures. Therefore, chemical additions to reduce SRP in litter and soil may be a best management practice in situations where eutrophication of adjacent water bodies due to P runoff has been identified. Preliminary calculations indicate that this .p ractice may be economically feasible. However, more research is needed to determine any beneficial and/or detrimental aspects of this practice

Design, analysis and testing of a piezoelectric flex transducer for harvesting bio-kinetic energy

This is the final version of the article. Available from IOP Publishing via the DOI in this record.The increasing prevalence of low power consuming electronics brings greater potential to mobile energy harvesting devices as a possible power source. A new piezoelectric energy harvesting device, called the piezoelectric flex transducer (PFT), is presented and developed. A Finite Element Model (FEM) was developed to design and analyse the PFT. The PFT consists of a piezoelectric element sandwiched between substrate layers and metal endcaps that are able to amplify the axial force on the piezoelectric element. Based on the concept of the Cymbal transducer, the PFT can withstand higher forces, was retrofitted into a shoe and used to power a wireless sensor module whilst the subject with a body weight of 760N was wearing the shoe and ran at 3.1mph (1.4HZ on shoe), the PFT produced an average maximum power of 2.5mW (over 2M? load).The authors gratefully acknowledge support from SmartWater: “Smart Sensor Network with energy harvesting for real time monitoring in urban water infrastructure” (FP7-People-2-12-IRSES project, EC318985) and to Wojczech Suder at the Welding Institute (Cranfield University) for welding the PFT

Benefits and Risks of Weight-Loss Treatment for Older, Obese Women

Background: A key issue in the treatment of obesity in older adults is whether the health benefits of weight loss outweigh the potential risks with respect to musculoskeletal injury. Objective: To compare change in weight, improvements in metabolic risk factors, and reported musculoskeletal adverse events in middle-aged (50-59 years) and older (65-74 years), obese women. Materials and methods: Participants completed an initial 6-month lifestyle intervention for weight loss, comprised of weekly group sessions, followed by 12 months of extended care with biweekly contacts. Weight and fasting blood samples were assessed at baseline, month 6, and month 18; data regarding adverse events were collected throughout the duration of the study. Results: Both middle-aged (n = 162) and older (n = 56) women achieved significant weight reductions from baseline to month 6 (10.1 +/- 0.68 kg and 9.3 +/- 0.76 kg, respectively) and maintained a large proportion of their losses at month 18 (7.6 +/- 0.87 kg and 7.6 +/- 1.3 kg, respectively); there were no significant differences between the two groups with respect to weight change. Older women further experienced significant reductions in systolic blood pressure, HbA(1c), and C-reactive protein from baseline to month 6 and maintained these improvements at month 18. Despite potential safety concerns, we found that older women were no more likely to experience musculoskeletal adverse events during the intervention as compared with their middle-aged counterparts. Conclusion: These results suggest that older, obese women can experience significant health benefits from lifestyle treatment for obesity, including weight loss and improvements in disease risk factors. Further investigation of the impact of weight loss on additional health-related parameters and risks (eg, body composition, muscular strength, physical functioning, and injuries) in older adults is needed.National Heart, Lung and Blood Institute R18HL73326University of FloridaDivision of Statistics and Scientific Computatio

Study of the glass transition in the amorphous interlamellar phase of highly crystallized poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) is a semi--crystalline polymer that can be crystallized to different degrees heating from the amorphous state. Even when primary crystallization has been completed, secondary crystallization can take place with further annealing and modify the characteristics of the amorphous interlamellar phase. In this work we study the glass transition of highly crystallized PET and in which way it is modified by secondary crystallization. Amorphous PET samples were annealed for 4 hours at temperatures between 140C and 180C. The secondary crystallization process was monitored by differential scanning calorimetry and the glass transition of the remaining interllamelar amorphous phase was studied by Thermally Stimulated Depolarization Currents measurements. Non--isothermal window polarization is employed to resolve the relaxation in modes with a well--defined relaxation time that are subsequently adjusted to several standard models. Analysis of experimental results, show that cooperativity is reduced to a great extend in the interlamellar amorphous regions. The evolution of the modes on crystallization temperature reveals that large scale movements are progressively replaced by more localized ones, with higher frequency, as crystallization takes place at higher temperatures. As a consequence, the glass transition temperature of the amorphous interlamellar phase tends to lower values for higher annealing temperatures. Evolution of calorimetric scans of the glass transition are simulated from the obtained results and show the same behaviour. The interpretation of these results in terms of current views about secondary crystallization is discussed.Comment: 30 pages, 5 tables, 12 figures; figure 5 modifie

Cloaked Facebook pages: Exploring fake Islamist propaganda in social media

This research analyses cloaked Facebook pages that are created to spread political propaganda by cloaking a user profile and imitating the identity of a political opponent in order to spark hateful and aggressive reactions. This inquiry is pursued through a multi-sited online ethnographic case study of Danish Facebook pages disguised as radical Islamist pages, which provoked racist and anti-Muslim reactions as well as negative sentiments towards refugees and immigrants in Denmark in general. Drawing on Jessie Daniels’ critical insights into cloaked websites, this research furthermore analyses the epistemological, methodological and conceptual challenges of online propaganda. It enhances our understanding of disinformation and propaganda in an increasingly interactive social media environment and contributes to a critical inquiry into social media and subversive politics

Segregation by thermal diffusion in granular shear flows

Segregation by thermal diffusion of an intruder immersed in a sheared granular gas is analyzed from the (inelastic) Boltzmann equation. Segregation is induced by the presence of a temperature gradient orthogonal to the shear flow plane and parallel to gravity. We show that, like in analogous systems without shear, the segregation criterion yields a transition between upwards segregation and downwards segregation. The form of the phase diagrams is illustrated in detail showing that they depend sensitively on the value of gravity relative to the thermal gradient. Two specific situations are considered: i) absence of gravity, and ii) homogeneous temperature. We find that both mechanisms (upwards and downwards segregation) are stronger and more clearly separated when compared with segregation criteria in systems without shear.Comment: 8 figures. To appear in J. Stat. Mec