Quiet propulsive lift for commuter airlines

The performance of STOL or RTOL aircraft and NASA's research program to provide options for future design and certification of quiet propulsive-life transports is described

Effect of Processing Parameters on the Density and Microstructure of Direct Laser Sintered Al-12Si Powders

The effect of processing parameters on the sintering behaviour of gas atomised Al-12Si powders has been investigated. Laser power, scanning rate, scan spacing and layer thickness are found to control the densification and the resultant microstructural characteristics of the laser sintered parts. It was found that sintered density increased as the energy density increased reaching a maximum of 80.2% at an energy input per unit volume of 67 J mm-3. For parts produced with a slightly lower power density (50 J mm-3), the microstructure consisted of fine dendrites with interconnected porosity while parts fabricated with a slightly higher power density (100 J mm-3) were noted to have a preponderance of coarse dendrites with a discontinuous network of irregular shaped pores surrounded by a fully dense aluminium-silicon matrix.Mechanical Engineerin

The Treatment and Prevention of Tuberculosis in the Tropics

The original intention of this thesis was to furnish an account of anti-tuberculosis measures in a small tropical community, to outline the problems ecnountered in such work and to describe the methods employed in overcoming them. Before doing this it was considered advisable to make a comparative study of the problems of other tropical countries. This involved an extensive search through numerous medical journals published in all parts of the world. The first part of this thesis therefore has been devoted to selecting, as far as possible, the more important contributions regarding tubeculosis amongst coloured peoples. Further, in certain sections, especially that on pathology, these articles have been set out in considerable detail in the hope that, ultimately, the information contained therein will be of value to those who have to wage a singla handed warfare against this disease

Evolutionary Explanation and the Record of Interest: Using Evolutionary Archaeology and Dual-Inheritance Theory to Explain the Archaeological Record

Book description: This volume offers an integrative approach to the application of evolutionary theory in studies of cultural transmission and social evolution and reveals the enormous range of ways in which Darwinian ideas can lead to productive empirical research, the touchstone of any worthwhile theoretical perspective. While many recent works on cultural evolution adopt a specific theoretical framework, such as dual inheritance theory or human behavioral ecology, Pattern and Process in Cultural Evolution emphasizes empirical analysis and includes authors who employ a range of backgrounds and methods to address aspects of culture from an evolutionary perspective. Editor Stephen Shennan has assembled archaeologists, evolutionary theorists, and ethnographers, whose essays cover a broad range of time periods, localities, cultural groups, and artifacts

An imagined community of practice: Online discourse among wheelchair users

People with disabilities often live in local communities primarily made up of people without disabilities: in the absence of a geographic community of people with disabilities, the internet becomes a valuable tool for connecting individuals across both local and global contexts. The power of computer-mediated communication (CMC) to allow individuals to interact both locally and globally has been well-studied in linguistics (e. g. Baron 2008; Page 2012), and this work has included the discourse of e-health (e. g. Hamilton 1998; Locher 2006, 2013) and the online discourse of people with disabilities (Al Zidjaly 2011, 2015). Less research has been done, however, on the implications of online discourse for understanding people with disabilities as a linguistic community.This paper argues that the community of people with disabilities can be viewed from a linguistic perspective as an imagined community of practice: an imagined community, because members recognize their common belonging even if they do not interact locally (Anderson 1983); a community of practice, because members use recognizable, if not identical, disability practices and engage in shared sense-making (Eckert 2006; Eckert/McConnell-Ginet 1992). This understanding of the community of people with disabilities is evidenced in online blogs by wheelchair users.A close discourse analysis of the blog posts shows shared sense-making around disability practices, even though individual bloggers’ practices may vary according to their specific strategies for accommodation. In their posts, the bloggers construct their disability identities in terms of practice and imagine themselves to belong to a community that is distinguished by disability practice. The analysis reveals shared sense-making: in particular, the way that the bloggers position themselves in opposition to the societal discourse that people with disabilities are an inspiration to people without them. In this way, the bloggers demonstrate their membership within an imagined community of practice made up of people with disabilities

“Taking the Cure”: Alcoholism and Recovery in the Fiction of Raymond Carver

Alcoholism plays a major role in modern American fiction; it serves as a reminder not only of a serious social problem, but also of an underlying and even more troubling malaise. Hemingway\u27s The Sun Also Rises, for example, is famous as an alcoholic novel, full of drinking and drunkenness, quarreling and remorse. Considered by Jung to be a misdirected spiritual craving, described by a member of Alcoholics Anonymous as the attempt to fill a bottomless neediness, the abuse of alcohol serves as a powerful metaphor for the thirst of modern man that cannot be quenched with material drink: Jake and Lady Ashley and the rest drink and drink, but are never satisfied. By focusing on this metaphor, we see Hemingway\u27s novel—and much of American fiction depicting alcoholism—as a prose companion to Eliot\u27s The Waste Land, the modern epic poem of spiritual dryness

What is marine biodiversity? Towards common concepts and their implications for assessing biodiversity status

Biodiversity' is one of the most common keywords used in environmental sciences, spanning from research to management, nature conservation, and consultancy. Despite this, our understanding of the underlying concepts varies greatly, between and within disciplines as well as among the scientists themselves. Biodiversity can refer to descriptions or assessments of the status and condition of all or selected groups of organisms, from the genetic variability, to the species, populations, communities, and ecosystems. However, a concept of biodiversity also must encompass understanding the interactions and functions on all levels from individuals up to the whole ecosystem, including changes related to natural and anthropogenic environmental pressures. While biodiversity as such is an abstract and relative concept rooted in the spatial domain, it is central to most international, European, and national governance initiatives aimed at protecting the marine environment. These rely on status assessments of biodiversity which typically require numerical targets and specific reference values, to allow comparison in space and/or time, often in association with some external structuring factors such as physical and biogeochemical conditions. Given that our ability to apply and interpret such assessments requires a solid conceptual understanding of marine biodiversity, here we define this and show how the abstract concept can and needs to be interpreted and subsequently applied in biodiversity assessments