5,364 research outputs found

    Computer control of a scanning electron microscope for digital image processing of thermal-wave images

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    Using a recently developed technology called thermal-wave microscopy, NASA Lewis Research Center has developed a computer controlled submicron thermal-wave microscope for the purpose of investigating III-V compound semiconductor devices and materials. This paper describes the system's design and configuration and discusses the hardware and software capabilities. Knowledge of the Concurrent 3200 series computers is needed for a complete understanding of the material presented. However, concepts and procedures are of general interest

    Carbide coated fibers in graphite-aluminum composites

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    The NASA-supported program at the Los Alamos Scientific Laboratory (LASL) to develop carbon fiber-aluminum matrix composites is described. Chemical vapor deposition (CVD) was used to uniformly deposit thin, smooth, continuous coats of TiC on the fibers of graphite tows. Wet chemical coating of fibers, followed by high-temperature treatment, was also used, but showed little promise as an alternative coating method. Strength measurements on CVD coated fiber tows showed that thin carbide coats can add to fiber strength. The ability of aluminum alloys to wet TiC was successfully demonstrated using TiC-coated graphite surfaces. Pressure-infiltration of TiC- and ZrC-coated fiber tows with aluminum alloys was only partially successful. Experiments were performed to evaluate the effectiveness of carbide coats on carbon as barriers to prevent reaction between alluminum alloys and carbon. Initial results indicate that composites of aluminum and carbide-coated graphite are stable for long periods of time at temperatures near the alloy solidus

    Carbide coated fibers in graphite-aluminum composites

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    The study of protective-coupling layers of refractory metal carbides on the graphite fibers prior to their incorporation into composites is presented. Such layers should be directly wettable by liquid aluminum and should act as diffusion barriers to prevent the formation of aluminum carbide. Chemical vapor deposition was used to uniformly deposit thin, smooth, continuous coats of ZrC on the carbon fibers of tows derived from both rayon and polyacrylonitrile. A wet chemical coating of the fibers, followed by high-temperature treatment, was used, and showed promise as an alternative coating method. Experiments were performed to demonstrate the ability of aluminum alloys to wet carbide surfaces. Titanium carbide, zirconium carbide and carbide-coated graphite surfaces were successfully wetted. Results indicate that initial attempts to wet surfaces of ZrC-coated carbon fibers appear successful

    Carbide coated fibers in graphites-aluminum composites

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    Research activities are described for a NASA-supported program at the Los Alamos Scientific Laboratory to develop graphite fiber-aluminum matrix composites. A chemical vapor deposition apparatus was constructed for continuously coating graphite fibers with TiC. As much as 150 meters of continuously coated fibers were produced. Deposition temperatures were varied from 1365 K to about 1750 K, and deposition time from 6 to 150 seconds. The 6 sec deposition time corresponded to a fiber feed rate of 2.54 m/min through the coater. Thin, uniform, adherent TiC coats, with thicknesses up to approximately 0.1 micrometer were produced on the individual fibers of Thornel 50 graphite yarns without affecting fiber strength. Although coat properties were fairly uniform throughout a given batch, more work is needed to improve the batch-to-batch reproducibility. Samples of TiC-coated Thornel 50 fibers were infiltrated with an aluminum alloy and hot-pressed in vacuum to produce small composite bars for flexure testing. Strengths as high as 90% of the rule-of-mixtures strength were achieved. Results of the examination of the fracture surfaces indicate that the bonding between the aluminum and the TiC-coated fibers is better than that achieved in a similar, commercially infiltrated material made with fibers having no observable surface coats. Several samples of Al-infiltrated, TiC-coated Thornel 50 graphite yarns, together with samples of the commercially infiltrated, uncoated fibers, were heated for 100 hours at temperatures near the alloy solidus. The TiC-coated samples appear to undergo less reaction than do the uncoated samples. Photomicrographs are shown

    “Free Will and Affirmation: Assessing Honderich’s Third Way”

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    In the third and final part of his A Theory of Determinism (TD) Ted Honderich addresses the fundamental question concerning “the consequences of determinism.” The critical question he aims to answer is what follows if determinism is true? This question is, of course, intimately bound up with the problem of free will and, in particular, with the question of whether or not the truth of determinism is compatible or incompatible with the sort of freedom required for moral responsibility. It is Honderich’s aim to provide a solution to “the problem of the consequences of determinism” and a key element of this is his articulation and defence of an alternative response to the implications of determinism that collapses the familiar Compatibilist/Incompatibilist dichotomy. Honderich offers us a third way – the response of “Affirmation” (HFY 125-6). Although his account of Affirmation has application and relevance to issues and features beyond freedom and responsibility, my primary concern in this essay will be to examine Honderich’s theory of “Affirmation” as it concerns the free will problem

    Electron beam induced damage in PECVD Si3N4 and SiO2 films on InP

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    Phosphorus rich plasma enhanced chemical vapor deposition (PECVD) of silicon nitride and silicon dioxide films on n-type indium phosphide (InP) substrates were exposed to electron beam irradiation in the 5 to 40 keV range for the purpose of characterizing the damage induced in the dielectic. The electron beam exposure was on the range of 10(exp -7) to 10(exp -3) C/sq cm. The damage to the devices was characterized by capacitance-voltage (C-V) measurements of the metal insulator semiconductor (MIS) capacitors. These results were compared to results obtained for radiation damage of thermal silicon dioxide on silicon (Si) MOS capacitors with similar exposures. The radiation induced damage in the PECVD silicon nitride films on InP was successfully annealed out in an hydrogen/nitrogen (H2/N2) ambient at 400 C for 15 min. The PECVD silicon dioxide films on InP had the least radiation damage, while the thermal silicon dioxide films on Si had the most radiation damage

    The role of social prescribers in wales:a consensus methods study

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    AIMS: Social prescribing continues to grow and change across healthcare services in Wales; however, research of the day-to-day performance of social prescribers is limited. This study aimed to explore which roles are perceived to be the most important and frequently used by social prescribers in Wales and compare these results to reports in studies of services in other countries in order to support future role development and potential standardisation. METHODS: This study used the Group Concept Mapping via the Concept Systems Global Max™ software to collect and analyse all data from both participants and literature. RESULTS: There was a total of 101 statements generated (119 participants, 84 literature) ranging from generic interpersonal skills to specialised training (cognitive behavioural therapy). These statements were then sorted by conceptual similarity into seven clusters (Providing a Specialist Service, Working in a person-centred way, Skills, Connecting Clients with Community, Collaborative Working, Evaluating and postprogramme duties, and Networking/Community). Statements were rated based on their perceived importance and frequency, with the ‘Skills’ cluster having the highest overall average and ‘Providing a Specialist Service’ having the lowest. CONCLUSIONS: Reports indicate that in general there is variation in the roles performed by individual participants in Wales; however, greater variation was observed between participants and literature suggesting geographical divergence in practice. In the top 12 highest rated statements for both frequency and importance, individualistic traits such as empathy and ‘being a listener’ are favoured over specialised methods such as cognitive behavioural therapy and behaviour change taxonomy. Results suggest that local need plays a part in the choices and performance of social prescribers and as such should be considered in future standardisation

    Enhancing consumers' self-reported loyalty intentions in Islamic Banks: the relationship between service quality and the mediating role of customer satisfaction

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    The main objective of this paper is to investigate how service quality and customer satisfaction are correlated to self-reported loyalty intentions in Islamic banks. The paper presents primary data collected by self-administered questionnaires involving a sample of 655 respondents from all local Islamic Banks in Jordan. The results show that compliance, tangibility, responsiveness, assurance, and empathy positively linked to self-reported loyalty intentions, with compliance and assurance appearing as the greatest correlation with self-reported loyalty intentions compared to other service quality dimensions. Islamic banks should focus on continuous improvement of service quality due to the direct correlation with customer satisfaction and loyalty. It is important for Islamic banks to review and endorse all policies and procedures to ensure that their documents and investments are undertaken in line with the requirements of Islamic law. Managers should pay special attention to the service quality provided by their employees and develop their skill set through training and education programmes based on Islamic principles. As the first study of its kind in Jordan, the paper’s contribution stems from filling the research gap in examining the relationship between the various service quality dimensions and self-reported loyalty intentions in Islamic banks using the CARTER model. Subjects: Marketing; Services Marketing; Consumer Behaviou
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