344 research outputs found
A critical assessment of UH-60 main rotor blade airfoil data
Many current comprehensive rotorcraft analyses employ lifting-line methods that require main rotor blade airfoil data, typically obtained from wind tunnel tests. In order to effectively evaluate these lifting-line methods, it is of the utmost importance to ensure that the airfoil section data are free of inaccuracies. A critical assessment of the SC1095 and SC1094R8 airfoil data used on the UH-60 main rotor blade was performed for that reason. Nine sources of wind tunnel data were examined, all of which contain SC1095 data and four of which also contain SC1094R8 data. Findings indicate that the most accurate data were generated in 1982 at the 11-Foot Wind Tunnel Facility at NASA Ames Research Center and in 1985 at the 6-inch by 22-inch transonic wind tunnel facility at Ohio State University. It has not been determined if data from these two sources are sufficiently accurate for their use in comprehensive rotorcraft analytical models of the UH-60. It is recommended that new airfoil tables be created for both airfoils using the existing data. Additional wind tunnel experimentation is also recommended to provide high quality data for correlation with these new airfoil tables
Soot surface growth and oxidation in laminar unsaturated-hydrocarbon/air diffusion flames
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77246/1/AIAA-2002-1116-550.pd
Corporate governance and employees in South Africa.
Focusing on employees as stakeholders, we analyse corporate governance initiatives in South Africa encouraging and requiring companies to look beyond their shareholders' interests. Successive non-binding codes and the provisions of the recent Companies Act 2008 promoting this have been lauded by many commentators. The 2008 Act provides certain opportunities for employees and their representatives to exercise influence at the margins. We nevertheless question how far current corporate governance initiatives are adequate to promote employee interests. On the basis of three case studies of how companies have responded to employees as stakeholders, we conclude that in fact more stringent regulation is required
Stadium Architecture and Regional Economic Development: International Experience and the Plans of Durban
For the FIFA World Cup 2010, South Africa plans to invest heavily. The positive economic effects that the country is hoping for stand in contrast to almost all statistical ex-post studies. This contribution emphasises that these results, usually from research under-taken in the USA, can only be generalised to a limited degree. The density of sports venues in developed countries is so high, that the marginal effects of new stadia are necessarily limited. We also emphasise that stadium design around the world was not hitherto adequately targeted towards positive economic effects. The example of Durban and its plans for a new iconic stadium is used to illustrate fundamental principles of stadium design and their embedding in a re-urbanisation process that have to be undertaken in order to consciously achieve positive regional economic effects
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A Scoping Review of Quality of Life Questionnaires in Glaucoma Patients
PRECIS: Multiple questionnaires exist to measure glaucoma's impact on quality of life (QoL). Selecting the right questionnaire for the research question is essential, as is patients' acceptability of the questionnaire to enable collection of relevant patient-reported outcomes.
PURPOSE: QoL relating to a disease and its treatment is an important dimension to capture. This scoping review sought to identify the questionnaires most appropriate for capturing the impact of glaucoma on QoL.
METHODS: A literature search of QoL questionnaires used in glaucoma, including patient-reported outcomes measures, was conducted and the identified questionnaires were analyzed using a developed quality criteria assessment.
RESULTS: Forty-one QoL questionnaires were found which were analyzed with the detailed quality criteria assessment leading to a summary score. This identified the top 10 scoring QoL questionnaires rated by a synthesis of the quality criteria grid, considering aspects such as reliability and reproducibility, and the authors' expert clinical opinion. The results were ratified in consultation with an international panel of ophthalmologists (N=49) from the Educational Club of Ocular Surface and Glaucoma representing 23 countries.
CONCLUSIONS: Wide variability among questionnaires used to determine vision related QoL in glaucoma and in the responses elicited was identified. In conclusion, no single existing QoL questionnaire design is suitable for all purposes in glaucoma research, rather we have identified the top 10 from which the questionnaire most appropriate to the study objective may be selected. Development of a new questionnaire that could better distinguish between treatments in terms of vision and treatment-related QoL would be useful that includes the patient perspective of treatment effects as well as meeting requirements of regulatory and health authorities. Future work could involve development of a formal weighting system with which to comprehensively assess the quality of QoL questionnaires used in glaucoma
‘We secured the tussac’: Accounts of ecological discovery, exploitation and renewal in the Falkland Islands
Sheep farms dominate the Falkland Islands landscape and have for over a century. The introduction of sheep, and several other species, has significantly transformed the ecology of this archipelago—the near elimination of tussac grass being one of the most notable changes.
Tracing back to early accounts of tussac grass in the ‘Falklands’, this paper captures its discovery, exploitation and current stage of renewal, including a closer look at the connections between tussac and livestock farming, as well as parallel trends in other countries.
We narrate changing relations between people and tussac grass using a combination of interview data, historical accounts and scientific literature.
Tussac is presented as a historical bellwether of shifting trends in local farm and environmental management in this isolated archipelago. Shifts in land ownership, grazing management methods and conservation efforts are bringing momentum to a period of renewal across the Falklands
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