Production of superconductor/carbon bicomponent fibers

Certain materials are unable to be drawn or spun into fiber form due to their improper melting characteristics or brittleness. However, fibrous samples of such materials are often necessary for the fabrication of intricate shapes and composites. In response to this problem, a unique process, referred to as the piggyback process, was developed to prepare fibrous samples of a variety of nonspinnable ceramics. In this technique, specially produced C shaped carbon fibers serve as micromolds to hold the desired materials prior to sintering. Depending on the sintering atmosphere used, bicomponent or single component fibers result. While much has been shown worldwide concerning the YBa2Cu3O(7-x) superconductor, fabrication into unique forms has proven quite difficult. However, a variety of intricate shapes are necessary for rapid commercialization of the superconducting materials. The potential for producing fibrous samples of the YBa2Cu3O(7-x) compound by the piggyback process is being studied. Various organic and acrylic materials were studied to determine suspending ability, reactivity with the YBa2Cu3O(7-x) compound during long term storage, and burn out characteristics. While many questions were answered with respect to the interfacial reactions between YBa2Cu3O(7-x) and carbon, much work is still necessary to improve the quality of the sintered material if the fibers produced are to be incorporated into useful composite or cables

Production of superconductor/carbon bicomponent fibers

Certain materials are unable to be drawn or spun into fiber form due to their improper melting characteristics or brittleness. However, fibrous samples of such materials are often necessary for the fabrication of intricate shapes and composites. In response to this problem, a unique process, referred to as the piggyback process, was developed to prepare fibrous samples of a variety of nonspinnable ceramics. In this technique, specially produced C-shaped carbon fibers serve as micromolds to hold the desired materials prior to sintering. Depending on the sintering atmosphere used, bicomponent or single component fibers result. While much has been demonstrated worldwide concerning the YBa2Cu3O(7-x) superconductor, fabrication into unique forms has proven quite difficult. However, a variety of intricate shapes are necessary for rapid commercialization of the superconducting materials. The potential for producing fibrous samples of the YBa2Cu3O(7-x) compound by the piggyback process is being investigated. Various organic and acrylic materials were investigated to determine suspending ability, reactivity with the YBa2Cu3O(7-x) compound during long term storage, and burn out characteristics. While many questions were answered with respect to the interfacial reactions between YBa2Cu3O(7-x) and carbon, much work is still necessary to improve the quality of the sintered material if the fibers produced are to be incorporated into useful composites or cables. Additional research is necessary to evaluate quality of the barrier layer during long soakings at the peak temperature; adjust the firing schedule to avoid microcracking and improve densification; and increase the solids loading in the superconductive suspension to decrease porosity

New Data to the Knowledge on the Corticolous Mite Fauna in Hungary (Acari: Prostimata, Astigmata, Oribatida)

Authors give a report on the results of the regular collections made between 1990 and 1998 on ornamental trees and shrubs,on streets, in parks, in green spaces of housing estates, in private gardens and in arboreta. A total of 19 corticolous mite species were found belonging to 14 families.Michaelopus corticalis (Michael,1885), Hericia hericia Robin,1868, Eupalopsis maseriensis (Canestrini et Fanzago, 1876), Mediolata vandergeesti (Gomaa et Bolland,1982), Cunaxoides kielczewskii Michocka, 1982, and Neophyllobius spec.nov. are reported for the first time for the Hungarian fauna. Hemisarcoptes budensis Fain et Ripka, 1998, M.corticalis and Cheletogenes ornatus (Canestrini et Fanzago,1876) were the most frequent species in the acarofauna associated with scale insects

Psychometric Testing of the Heart Failure Somatic Awareness Scale

Background: Self-management of heart failure relies on patients to assess their symptoms, but their ability to do so is often difficult to determine. The 12-item self-report Heart Failure Somatic Awareness Scale (HFSAS) was developed to measure awareness of and distress secondary to heart failure symptoms. The purpose of this study was to test the psychometric properties of the HFSAS. Methods and Results: Feasibility and discriminant validity of the HFSAS were tested in 49 patients admitted for an exacerbation of heart failure. The HFSAS was acceptable to patients and discriminated between heart failure symptoms and anxiety (r = 0.25, P = .08). When reliability and validity were tested in 201 patients with acute heart failure, theta reliability was adequate (0.71). The HFSAS was low to moderately correlated with general bodily awareness (r = 0.48). No difference was found based on gender, but younger patients had higher mean and median HFSAS scores (more distress). The HFSAS was a significant predictor of symptom duration prior to seeking care for heart failure; higher scores were associated with longer delay before seeking care. Conclusion: The HFSAS is reliable with content, discriminant, and construct validity. Evaluation of its usefulness in teaching patients to monitor daily symptoms is needed

Internal cardiac defibrillation: Histopathology and temporal stability of defibrillation energy requirements

The automatic implantable cardioverter/defibrillator is tested intraoperatively to ensure effectiveness by performing a number of induced fribrillation-defibrillation trials. The temporal stability of defibrillation energy requirements and the histopathologic effects of multiple defibrillating shocks were studied in 12 dogs chronically instrumented with an internal spring-patch lead system identical to that used in humans. Dogs were studied on days 1, 11, 18, 25 and 32. Data were analyzed by logistic regression and the energy required for 50% (E50) and 80% (E80) success was compared. On day 32 the dogs were killed and the heart was removed for gross and microscopic pathologic examination.There was a significant decrease in energy requirements from day 1 to day 11, as the E50decreased from 6.9 ± 4.5 to 4.9 ± 2.5 J (p < 0.02) and the E80decreased from 8.5 ± 5.2 to 6.1 ± 3.4 J (p < 0.02). The energy requirements then remained stable over the remainder of the experiment. The dogs were administered 209 ± 18 shocks (range 1 to 24 J) for a total cumulative dose of 1,524 ± 571 J. In all cases, both grossly and microscopically, there was no evidence of pathologic changes in the myocardium or coronary vessels. In all cases there was a fibrous plaque beneath the patch electrodes, at times containing an area of patchy hemorrhage; in a single specimen a mixed inflammatory infiltrate accompanied the hemorrhage. Endothelialization of the spring electrode with mild right atrial endocardial fibrosis was also observed.Therefore, the energy requirements for successful defibrillation decrease during the first 11 days after testing at implantation, and then remain stable. Also, multiple, closely spaced defibrillating shocks applied through the spring-patch electrode system do not cause myocardial damage or changes other than those associated with the implantation

Optimizing the process of product development by collaborating & thinking visually-co-creation within Howden

The paper explores the process of creating a bespoke New Product Development Procedure for the heavy engineering firm Howden through a collaborative Knowledge Transfer Partnership with the University of Strathclyde. The act of transferring knowledge was done by using a visual methodology and the paper explores the reasoning behind why using this methodology was so successful

Constraints, Histones, and the 30 Nanometer Spiral

We investigate the mechanical stability of a segment of DNA wrapped around a histone in the nucleosome configuration. The assumption underlying this investigation is that the proper model for this packaging arrangement is that of an elastic rod that is free to twist and that writhes subject to mechanical constraints. We find that the number of constraints required to stabilize the nuclesome configuration is determined by the length of the segment, the number of times the DNA wraps around the histone spool, and the specific constraints utilized. While it can be shown that four constraints suffice, in principle, to insure stability of the nucleosome, a proper choice must be made to guarantee the effectiveness of this minimal number. The optimal choice of constraints appears to bear a relation to the existence of a spiral ridge on the surface of the histone octamer. The particular configuration that we investigate is related to the 30 nanometer spiral, a higher-order organization of DNA in chromatin.Comment: ReVTeX, 15 pages, 18 figure