811 research outputs found

    Design and Manufacture of a Large-Bore 10 T Superconducting Dipole for the CERN Cable Test Facility

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    A large-bore 10 T superconducting dipole magnet was designed and fabricated in close cooperation between CERN and HMA Power Systems. The dipole has a length of about 1.7 m and an aperture of 88 mm and is composed of two two-layer poles wound with NbTi cables cooled to 1.9 K to reach magnetic inductions close to 10 T. This dipole will be installed at the CERN cable test facility and used as a background field magnet to test LHC superconducting cables. In its large aperture up to four cable samples can be tested at the same time. The mechanical design of the magnet is such that coil prestress variations between warm and cold conditions are kept within 20 MPa. A short model was also built and cooled down in order to check and confirm with test results the mechanical behavior of the dipole. Magnetic measurements, at room temperature, were performed upon its arrival at CERN prior to installation in the test facility. The dipole was recently cooled down and tested. This paper will discuss the design, the main manufacturing steps and the initial test results

    Metabolic, mental and immunological effects of normoxic and hypoxic training in multiple sclerosis patients: a pilot study

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    Background: Physical activity might attenuate inflammation and neurodegeneration in multiple sclerosis (MS). Erythropoietin, which is produced upon exposure to hypoxia, is thought to act as a neuroprotective agent in MS. Therefore, we studied the effects of intermittent hypoxic training on activity energy expenditure, maximal workload, serum erythropoietin, and immunophenotype focusing on regulatory and IL-17A-producing T cells. Methods: We assigned 34 relapsing-remitting MS patients within a randomized, single blind, parallel-group study to either normoxic (NO) or hypoxic (HO) treadmill training, both 3 times/week for 1 h over 4 weeks (Clinicaltrials.gov identifier: NCT02509897). Before and after training, activity energy expenditure (metabolic chamber), maximal workload (incremental treadmill test), walking ability, depressive symptoms (Beck Depression Inventory I), serum erythropoietin concentrations, and immunophenotype of peripheral blood mononuclear cells (PBMCs) were assessed. Results: Energy expenditure did not change due to training in both groups, but was rather fueled by fat than by carbohydrate oxidation after HO training (P = 0.002). Maximal workload increased by 40 Watt and 42 Watt in the NO and HO group, respectively (both P < 0.0001). Distance patients walked in 6 min increased by 25 m and 27 m in the NO and HO group, respectively (NO P = 0.02; HO P = 0.01). Beck Depression Inventory score markedly decreased in both groups (NO P = 0.03; HO P = 0.0003). NO training shifted Treg subpopulations by increasing and decreasing the frequency of CD39(+) and CD31(+) Tregs, respectively, and decreased IL-17A-producing CD4(+) cells. HO training provoked none of these immunological changes. Erythropoietin concentrations were within normal range and did not significantly change in either group. Conclusion: 4 weeks of moderate treadmill training had considerable effects on fitness level and mood in MS patients, both under normoxic and hypoxic conditions. Additionally, NO training improved Th17/Treg profile and HO training improved fatty acid oxidation during exercise. These effects could not be attributed to an increase of erythropoietin

    Testing of the large bore single aperture 1-meter superconducting dipoles made with phenolic inserts

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    Two identical single aperture 1-metre superconducting dipoles have been built in collaboration with HMA Power Systems and tested at CERN. The 87.8 mm aperture magnets feature a single layer coil wound using LHC main dipole outer layer cable, phenolic spacer type collars, and a keyed two part structural iron yoke. The magnets are designed as models of the D1 separation dipole in the LHC experimental insertions, whose nominal field is 4.5 T at 4.5 K. In this report we present the test results of the two magnets at 4.3 K and 1.9 K

    A Reinvestigation of some Alkali Chelates

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    Design, Fabrication and Initial Testing of a Large Bore Single Aperture 1 m Long Superconducting Dipole Made with Phenolic Inserts

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    In the framework of the LHC magnet development programme, a large bore single aperture 1-meter long superconducting dipole has been built in collaboration with HOLEC. The magnet features a single layer coil wound using the LHC main dipole outer layer cable, phenolic inserts, and a keyed two part structural iron yoke. This paper presents the magnetic and mechanical design and optimisation of the magnet. We describe the coil winding and curing, and present the construction and assembly procedures. Finally we report on the mechanical behaviour during assembly and cooling, and present the magnet training behaviour

    Mobilising sustainable building assessment models: agents, strategies and local effects

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    This paper considers how work on knowledge and policy mobilities can be used to analyse the processes behind and the local impacts of mobile sustainable building assessment models such as BREEAM and LEED. After reviewing existing concerns and critiques relating to the impacts of these models on the local sensitivity of sustainable building designs, consideration is given to the effects on local sensitivity of ‘who mobilizes’ the models, the ‘intercity issues’ associated with generating commensurability between places, and the way ‘events along the way’ are used to sell models. These questions reveal that work on knowledge and policy mobilities provides a useful framework through which to develop social science perspectives on the local impacts of mobile building assessment models. In particular, this approach highlights how processes of mobility are used to frame approaches to sustainable building design and potentially undermine attempts to render models sensitive to local challenges and solutions. It is, therefore, suggested that the knowledge and policy mobilities informed approach adopted here is beneficial as it places less emphasis on the intrinsic technical features of models and more emphasis on the powerful effects of processes of mobilisation on understandings and practices of sustainable design

    A driving simulator study to explore the effects of text size on the visual demand of in-vehicle displays

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    Modern vehicles increasingly utilise a large display within the centre console, often with touchscreen capability, to enable access to a wide range of driving and non-driving-related functionality. The text provided on such displays can vary considerably in size, yet little is known about the effects of different text dimensions on how drivers visually sample the interface while driving and the potential implications for driving performance and user acceptance. A study is described in which sixteen people drove motorway routes in a medium-fidelity simulator and were asked to read text of varying sizes (9 mm, 8 mm, 6.5 mm, 5 mm, or 4 mm) from a central in-vehicle display. Pseudo-text was used as a stimulus to ensure that participants scanned the text in a consistent fashion that was unaffected by comprehension. There was no evidence of an effect of text size on the total time spent glancing at the display, but significant differences arose regarding how glances were distributed. Specifically, larger text sizes were associated with a high number of relatively short glances, whereas smaller text led to a smaller number of long glances. No differences were found in driving performance measures (speed, lateral lane position). Drivers overwhelmingly preferred the ‘compromise’ text sizes (6.5 mm and 8 mm). Results are discussed in relation to the development of large touchscreens within vehicles

    Thermal Decomposition of Sodium Acetylacetonate

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    Bonding in Alkali and Alkaline Earth Acetylacetonates

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    Infrared, ultraviolet, and nuclear magnetic resonance spectroscopies have been used to obtain quantitative data to establish the nature of bonding in alkali and alkaline earth acetylacetonates. Most of these acetylacetonates are salt-like; however the properties of lighter metal complexes reflect a covalent (“benzenoid”) character. Within a family the change from benzenoid to ionic character is quite abrupt, occurring between lithium and sodium compounds for the alkali metals, and between beryllium and calcium for the alkaline earths, with the magnesium compound being intermediate. The ionic compounds hydrolyze readily unless totally water-free environments are used. The claim of a more covalent structure for the hydrated form, as opposed to the non-hydrated form of a given acetylacetonate is not supported by the results of this study
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