Lightweight piston

A lightweight piston composed of carbon-carbon composites is presented. The use of carbon-carbon composites over conventional materials, such as aluminum, reduces piston weight and improves thermal efficiency of the internal combustion reciprocation engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance is so small as to eliminate the necessity for piston rings. Use of the carbon-carbon composite has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance

Composite piston

A composite piston structure is disclosed which provides a simple and reliable means for joining a carbon-carbon or ceramic piston cap with a metallic piston body. Attachment is achieved by means of a special geometry which compensates for differences in thermal expansion without complicated mechanical fastening devices. The shape employs a flange created by opposed frustoconical shapes with coincident vertices intersecting on the radial centerline of the piston in order to retain the piston cap. The use of carbon-carbon for the piston cap material allows a close fit between the piston and a cylinder wall, eliminating the need for piston rings. The elimination of extra mechanical parts of previous composite pistons provides a lightweight composite piston capable of extended high temperature operation

Lightweight piston architecture

The invention is an improvement in a lightweight carbon-carbon composite piston, the improvement uses near-net shape knitted or warp-interlock preforms to improve the structural qualities of the piston. In its preferred embodiment, a one piece, tubular, closed-ended, knitted preform (a sock) of carbon fibers embedded within the matrix of the piston structure forms the crown, side wall, skirt and inner surface of the piston, and wrap-interlock preforms strengthen the piston crown and wrist pin bosses

Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces has line element extensions that pass through a common point

Cryogenic Insulation System

This invention relates to reusable, low density, high temperature cryogenic foam insulation systems and the process for their manufacture. A pacing technology for liquid hydrogen fueled, high speed aircraft is the development of a fully reusable, flight weight cryogenic insulation system for propellant tank structures. In the invention cryogenic foam insulation is adhesively bonded to the outer wall of the fuel tank structure. The cryogenic insulation consists of square sheets fabricated from an array of abutting square blocks. Each block consists of a sheet of glass cloth adhesively bonded between two layers of polymethacrylimide foam. Each block is wrapped in a vapor impermeable membrane, such as Kapton(R) aluminum Kapton(R), to provide a vapor barrier. Very beneficial results can be obtained by employing the present invention in conjunction with fibrous insulation and an outer aeroshell, a hot fuselage structure with an internal thermal protection system

An Overview of Structures and Materials for Future Space Vehicles

The NASA, primarily at Langley Research Center, has been conducting analytical and experimental developmental programs for high temperature structures for over 30 years. Over this time many significant technologies in both structures and materials have evolved. The structures and materials for primary airframe concepts such as metal-matrix composites, organic composites, advanced metals and carbon-carbon have emerged from laboratory curiousities to state-of-the-art structures. New manufacturing processes, such as electron beam welding, superplastic forming and diffusion bonding, allow innovative design concepts that were impracticable only a decade ago. Several of these technologies have been flight demonstrated as secondary structures such as flaps, rudders and speed brakes. Analytical techniques have improved to the point where the design and analysis of complex thermostructural concepts can be readily evaluated in relatively short time frames, when only 20 years ago these techniques were unknown. This paper reviews these technologies, proven, emerging and conceptual with emphasis on their applications to space vehicles

Uptake of advanced clinical practice roles in the health service in England: perspectives at the micro level

Health care organisations in many countries are developing advanced clinical practitioner roles to address workforce shortages and growing demand for services. Even in countries where advanced practice roles are more established there are low numbers, clustered in a limited range of professions, mostly nursing specialities. Successful implementation of national policies encouraging increased advanced practice roles and from a broader range of professions, requires attention to all levels of the health system. There is a lack of evidence as to the motivation to take-up these roles at the micro, individual actor level. This study explored the motivations important at the micro level in influencing a range of health professionals to undertake advanced practice roles. The study used an interpretive methodology with thematic analysis and was framed by theories of motivational domains in the work environment. Semi-structured interviews were undertaken with eighteen advanced clinical practitioners working in health care organisations in England. The motivators for role take-up were found to be predominantly intrinsic reflecting participants’ desires for advancement, both personal and for their profession, and improved efficiency of patient care. Participants described experiencing limited organisational support and sometimes discouragement from other professionals. There is potential for health organisations at the meso level of health care systems to support national growth of advanced practice roles by giving attention to the motivations of diverse health professionals. We propose a new theoretical framework of motivators for advanced clinical practice role uptake at the micro level

Are advanced clinical practice roles in England’s National Health Service a remedy for workforce problems? A qualitative study of senior staff perspectives

Objective: A major issue facing all health systems is improving population health while at the same time responding to both growing patient numbers and needs and developing and retaining the health care workforce. One policy response to workforce shortages has been the development of advanced clinical practice roles. In the context of an English national policy promoting such roles in the health service, we explored senior managers’ and senior clinicians’ perceptions of factors at the organization level that support or inhibit the introduction of advanced clinical practice roles. The investigation was framed by theories of the diffusion of innovation and the system of professions. Methods: We conducted a qualitative interview study of 39 senior manager and clinicians in 19 National Health Service acute, community, mental health and ambulance organizations across a metropolitan area in 2019. Results: Small numbers of advanced clinical practice roles were reported, often in single services. Four main influences were identified in the development of advanced clinical practice roles: staff shortages (particularly of doctors in training grades) combined with rising patient demand, the desire to retain individual experienced staff, external commissioners or purchasers of services looking to shape services in line with national policy, and commissioner-funded new roles in new ambulatory care services and primary care. Three factors were reported as enabling the roles: finance for substantive posts, evidence of value of the posts, and structural support within the organization. Three factors were perceived as inhibiting developing the roles: confusion and lack of knowledge amongst clinicians and managers, the availability of finance for the roles, and a nervousness (sometimes resistance) to introducing the new roles. Conclusions: While the national policy was to promote advanced clinical practice roles, the evidence suggested there was and would continue to be limited implementation at the operational level. Development scenarios that introduced new monies for such roles reduced some of the inhibiting factors. However, where the introduction of roles required funding to move from one part of a service to another, and potentially from one staff group to another, the growth of these roles was and is likely to be contested. In such scenarios, research and business evidence of relative advantage will be important, as too will be supporters in powerful positions. The paucity of publicly available evidence on the effectiveness of advanced clinical practice roles across the specialties and professions in the context requires urgent attention

Non-pharmacological interventions for Lewy body dementia: a systematic review.

Lewy body dementia (consisting of dementia with Lewy bodies and Parkinson's disease dementia) is a common neurodegenerative disease characterised by visual hallucinations, fluctuating attention, motor disturbances, falls, and sensitivity to antipsychotics. This combination of features presents challenges for pharmacological management. Given this, we sought to review evidence for non-pharmacological interventions with patients with Lewy body dementia and their carers. Bibliographic databases were searched using a wide range of search terms and no restrictions were placed on study design, language, or clinical setting. Two reviewers independently assessed papers for inclusion, rated study quality, and extracted data. The search identified 21 studies including two randomised controlled trials with available subgroup data, seven case series, and 12 case studies. Most studies reported beneficial effects of the interventions used, though the only sizeable study was on dysphagia, showing a benefit of honey-thickened liquids. Given the heterogeneity of interventions and poor quality of the studies overall, no quantitative synthesis was possible. Overall, identified studies suggested possible benefits of non-pharmacological interventions in Lewy body dementia, but the small sample sizes and low quality of studies mean no definite recommendations can be offered. Our findings underscore the clear and urgent need for future research on this topic

BBC2 and world cinema

© Edinburgh University Press. This article examines the origins of BBC2's reputation as a purveyor of films from around the world, exploring the significance and impact of the strand World Cinema (1965-74) and assessing the range and diversity of its offer. Foreign-language titles had been broadcast by the Corporation since before the Second World War, due partly to their ready availability at a time when Hollywood films were 'off limits', given the hostility of American (and British) film companies towards the new rival medium of television. During this early period, however, these continental films were not popular, undoubtedly due to the fact that subtitles were very difficult to read on small, low-definition television screens. BBC2, with its commitment to minority tastes and interests and its use of both the higher-definition 625-line UHF system and colour, was perfectly placed to revive and foster interest in world cinema. For those who urged broadcasters to adopt and maintain an enlightened film policy, World Cinema became exemplary, as a rare exception to the general rules in early television of editing for content or length, block buying (the practice of buying the rights to a mixed package of films in order to acquire certain gems) and haphazard scheduling. For a generation of cinephiles, World Cinema was a formative and educative experience. Particular attention is paid here to the first five years of World Cinema, which saw the strand give attention to a variety of 'New Waves' and relay experiences from behind the Iron Curtain and further afield