Wire electric-discharge machining and other fabrication techniques

Wire electric discharge machining and extrude honing were used to fabricate a two dimensional wing for cryogenic wind tunnel testing. Electric-discharge cutting is done with a moving wire electrode. The cut track is controlled by means of a punched-tape program and the cutting feed is regulated according to the progress of the work. Electric-discharge machining involves no contact with the work piece, and no mechanical force is exerted. Extrude hone is a process for honing finish-machined surfaces by the extrusion of an abrasive material (silly putty), which is forced through a restrictive fixture. The fabrication steps are described and production times are given

Basic health needs in Africa

African Studies Center Working Paper No. 2

The Sopono cult and smallpox vaccinations in Lagos

African Studies Center Working Paper No. 11INTRODUCTION: This paper examines the question of how African societies view conditions which Western society calls "disease," and how Africans respond to Western-oriented medical efforts to deal with "disease." This paper is based on data obtained before and during an international smallpox vaccination campaign in West Africa, among husbands and senior wives in a random sample of households •. All of the data were obtained in metropolitan Lagos, and the analysis focuses on members of the large Yoruba tribe who comprised 81 percent of the sample. It is recognized that an urban sample cannot be considered characteristic of either African or Yoruba society. At the same time, Lagos is regarded as peculiarly intensive in blend of African and Western influences (see especially Mabogunje, 1968), and the analysis also focuses on this aspect and derives special interest because of this concentration of social forces in one compact geographical area

Floristic variation in Sphagnum-dominated peatland communities of the Central Highlands, Victoria

The floristic composition of Sphagnum-dominated peatlands in the Central Highlands region of Victoria was surveyed (37º 25´ S; 145º 50´ E). NMDS ordination and cluster analysis divided the peatland sites into two broad groups with altitude being the most important factor separating these groups. Other important factors were aspect, slope and the amount of shade. Group 1 included subalpine sites that are similar to those found at higher altitudes further east in Victoria. Important species included Empodisma minus, Epacris paludosa, Richea continentis and Baeckea gunniana. The two species of Sphagnum present were Sphagnum cristatum and the more inundation-tolerant Sphagnum novozelandicum. Group 2 included montane peatlands with abundant Sphagnum cristatum. These sites range from broad wet heaths dominated by Richea victoriana and Carex appressa, to narrower cool temperate rainforest and riparian systems. The ‘rainforest’ peatlands are characterised by Leptospermum grandifolium, Nothofagus cunninghamii, Carex appressa and Blechnum penna-marina, and are in varying stages of post-fire succession regulated by sitespecific microclimate. The conservation status and catchment function of these peatlands are briefly discussed