55 resultados para New materials


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Electrochemical capacitors, also known as supercapacitors, are becoming increasingly important components in energy storage, although their widespread use has not been attained due to a high cost/ performance ratio. Fundamental research is contributing to lowered costs through the engineering of new materials. Currently the most viable materials used in electrochemical capacitors are biomassderived and polymer-derived activated carbons, although other carbon materials are useful research tools. Metal oxides could result in a step change for electrochemical capacitor technology and is an exciting area of research. The selection of an appropriate electrolyte and electrode structure is fundamental in determining device performance. Although there are still many uncertainties in understanding the underlying mechanisms involved in electrochemical capacitors, genuine progress continues to be made. It is argued that a large, collaborative international research programme is necessary to fully develop the potential of electrochemical capacitors.

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As a leading facility in laser-driven nuclear physics, ELI-NP will develop innovative research in the fields of materials behavior in extreme environments and radiobiology, with applications in the development of accelerator components, new materials for next generation fusion and fission reactors, shielding solutions for equipment and human crew in long term space missions and new biomedical technologies. The specific properties of the laser-driven radiation produced with two lasers of 1 PW at a pulse repetition rate of 1 Hz each are an ultra-short time scale, a relatively broadband spectrum and the possibility to provide simultaneously several types of radiation. Complex, cosmic-like radiation will be produced in a ground-based laboratory allowing comprehensive investigations of their effects on materials and biological systems. The expected maximum energy and intensity of the radiation beams are 19 MeV with 10^9 photon/pulse for photon radiation, 2 GeV with 108 electron/pulse for electron beams, 60 MeV with 10^12 proton/pulse for proton and ion beams and 60 MeV with 107 neutron/pulse for a neutron source. Research efforts will be directed also towards measurements for radioprotection of the prompt and activated dose, as a function of laser and target characteristics and to the development and testing of various dosimetric methods and equipment.

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OBJECTIVES: To identify the reasons why some people do not participate in bowel cancer screening so that steps can be taken to improve informed decision-making.

DESIGN: Qualitative study, using focus groups with thematic analysis of data to identify, analyse and report patterns. Transcripts were repeatedly read and inductively coded using a phenomenological perspective, and organised into key themes.

SETTING: Belfast and Armagh, two areas of Northern Ireland with relatively low uptake of bowel cancer screening.

PARTICIPANTS: Ten women and 18 men in three single-gender focus groups (two male and one female), each with 9-10 participants. Study participants were recruited by convenience sampling from the general public and were eligible for, but had not taken part in, the Northern Ireland Bowel Cancer Screening Programme.

RESULTS: Key themes identified were fear of cancer; the test procedure; social norms; past experience of cancer and screening; lack of knowledge or understanding about bowel cancer screening; and resulting behaviour towards the test. Fear about receiving bad news and reluctance to conduct the test themselves were reactions that participants seemed willing to overcome after taking part in open discussion about the test.

CONCLUSIONS: We identified barriers to participation in bowel cancer screening and used these insights to develop new materials to support delivery of the programme. Some of the issues raised have been identified in other UK settings, suggesting that knowledge about barriers, and strategies to improve uptake, may be generalisable.

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Index properties such as the liquid limit and plastic limit are widely used to evaluate certain geotechnical parameters of fine-grained soils. Measurement of the liquid limit is a mechanical process, and the possibility of errors occurring during measurement is not significant. However, this is not the case for plastic limit testing, despite the fact that the current method of measurement is embraced by many standards around the world. The method in question relies on a fairly crude procedure known widely as the ‘thread rolling' test, though it has been the subject of much criticism in recent years. It is essential that a new, more reliable method of measuring the plastic limit is developed using a mechanical process that is both consistent and easily reproducible. The work reported in this paper concerns the development of a new device to measure the plastic limit, based on the existing falling cone apparatus. The force required for the test is equivalent to the application of a 54 N fast-static load acting on the existing cone used in liquid limit measurements. The test is complete when the relevant water content of the soil specimen allows the cone to achieve a penetration of 20 mm. The new technique was used to measure the plastic limit of 16 different clays from around the world. The plastic limit measured using the new method identified reasonably well the water content at which the soil phase changes from the plastic to the semi-solid state. Further evaluation was undertaken by conducting plastic limit tests using the new method on selected samples and comparing the results with values reported by local site investigation laboratories. Again, reasonable agreement was found.

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The conceptual design of a new electron beam ion trap primarily intended for the study of electron-ion interactions is outlined along with some preliminary predictions regarding its capabilities. (C) 2003 Elsevier Science B.V. All rights reserved.

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Electron beam trajectory simulations have been performed to design a new electron beam ion trap. The design of the magnet and electrode structures was optimized based on the results of the simulations. (C) 2003 Elsevier Science B.V. All rights reserved.