Analytical screening of low emissions, high performance duct burners for supersonic cruise aircraft engines

An analytical screening study was conducted to identify duct burner concepts capable of providing low emissions and high performance in advanced supersonic engines. Duct burner configurations ranging from current augmenter technology to advanced concepts such as premix-prevaporized burners were defined. Aerothermal and mechanical design studies provided the basis for screening these configurations using the criteria of emissions, performance, engine compatibility, cost, weight and relative risk. Technology levels derived from recently defined experimental low emissions main burners are required to achieve both low emissions and high performance goals. A configuration based on the Vorbix (Vortex burning and mixing) combustor concept was analytically determined to meet the performance goals and is consistent with the fan duct envelope of a variable cycle engine. The duct burner configuration has a moderate risk level compatible with the schedule of anticipated experimental programs

Advanced composite combustor structural concepts program

An analytical study was conducted to assess the feasibility of and benefits derived from the use of high temperature composite materials in aircraft turbine engine combustor liners. The study included a survey and screening of the properties of three candidate composite materials including tungsten reinforced superalloys, carbon-carbon and silicon carbide (SiC) fibers reinforcing a ceramic matrix of lithium aluminosilicate (LAS). The SiC-LAS material was selected as offering the greatest near term potential primarily on the basis of high temperature capability. A limited experimental investigation was conducted to quantify some of the more critical mechanical properties of the SiC-LAS composite having a multidirection 0/45/-45/90 deg fiber orientation favored for the combustor linear application. Rigorous cyclic thermal tests demonstrated that SiC-LAS was extremely resistant to the thermal fatigue mechanisms that usually limit the life of metallic combustor liners. A thermal design study led to the definition of a composite liner concept that incorporated film cooled SiC-LAS shingles mounted on a Hastelloy X shell. With coolant fluxes consistent with the most advanced metallic liner technology, the calculated hot surface temperatures of the shingles were within the apparent near term capability of the material. Structural analyses indicated that the stresses in the composite panels were low, primarily because of the low coefficient of expansion of the material and it was concluded that the dominant failure mode of the liner would be an as yet unidentified deterioration of the composite from prolonged exposure to high temperature. An economic study, based on a medium thrust size commercial aircraft engine, indicated that the SiC-LAS combustor liner would weigh 22.8N (11.27 lb) less and cost less to manufacture than advanced metallic liner concepts intended for use in the late 1980's

Multiple Roles of a Rural Administrator

Basic administrative procedures are similar in rural and urban areas. Even so, rural human service administrators are often not prepared for the many roles they must assume in small and underfunded rural agencies. The roles may include personnel director, budget officer, accountant, fundraiser, supervisor, building and maintenance supervisor, volunteer coordinator, group developer, community organizer, public educator, policy analyst, and director of public relations and marketing

Financial Management: Social Agency, Social Enterprise and Social Economy

There has been a quiet revolution in financial management practice in social agencies in recent decades, symbolized by the transition from fund to enterprise accounting and increasing recognition of the ‘third sector’ of the social economy. The traditional voluntary agency model of donations has been joined by grants, performance contracts, ‘managed care’ and an array of other options, and traditional voluntary agency based and public agency practice now exist alongside corporate for profit service delivery and various forms of private practice. Social enterprise and entrepreneurship are a common theme in all this diversity, as social agencies must aggressively seek out financial support. In this environment, two models of budgeting, termed ‘common-pool’ and social enterprise budgeting have emerged

Nonprofit Community Service and the Hidden Cost of Information Technology

Will the information superhighway – like its concrete counterpart, the interstate highway system – turn out to be a good idea but too expensive to maintain properly? This paper will explore issues associated with the initial and ongoing costs of adopting information technology for nonprofit community service organizations, with particular attention to access and use of the information superhighway. Several possible explanations for the lag in adoption of internet technology will be explored. One of these will be the null hypothesis that resources and services currently available over the internet may still be insufficient to justify the costs involved for nonprofits. The paper will also explore the issue of long-term costs for nonprofits, by comparison with experiences in higher education. Decision-makers in business and higher education are already discovering that the initial startup costs of internet connection may only be the tip of what is beginning to look like a very large iceberg

Rural Social Work Bibliography (1999)

This bibliography was assembled in response to a request from OUP for a rural bibliography on their website prior to publication of our edited book on Rural Social Work Practice (Oxford University Press. 2005)

Urban-Designed Programs for the Rural Aged: Are They Exportable?

There are a variety of problems that affect older people in rural areas. In the first part of this paper, we examine four problems affecting the rural aged in particular: health, income, housing and social integration into rural communities. In the second part of the paper, we examine the question of whether programs to deal with these problems that have developed in various cities in the United States can readily be translated into rural communities. The paper concludes with a warning that the urban crisis, largely discovered by human services and other urbanists in the 1960s, is increasingly being expropriated as an issue by those whose primary concerns are reducing public spending and limiting local basic public services in both urban and rural areas

Aging and the Milieu of Social Policy

One facet of the new conservatism, which is drawing so much interest but not much information currently is the proposal for converting a large number of social service programs (including the Administration on Aging) into a single community block grant program. Even without the Reagan Administration and its new conservatism, however, the case for substantial--if less dramatic--changes in the network of services and programs which benefit the aged has been growing for some time. In this chapter, wel review some of the broader implications of current social policies for the aged, and some of the criticisms raised among gerontologists, concentrating on four principal areas: income policy; housing policy; services policy; and symbolic policy. We do so within the broad framework of social policy as a milieu for aging

Medicare, Medicaid and the Geriatric Residential Environment

This article reports on a study of interstate differences in the availability of nursing home beds, personal care home slots and public housing, and attempts to assess the impact of the adoption of Medicare and Medicaid six years before on the availability of these components of what was termed the geriatric residential environments continuum or GRE. The underlying idea is that components of long-term health care, personal care and housing/shelter are three common elements of a wide variety of public policy for the aged