235 research outputs found
Apparatus and method for explosive bonding to edge of flyer plate
The invention is an apparatus and a process for the explosive joining of a flyer plate and a base plate. The apparatus consists of a flyer plate positioned over a base plate. The flyer plate has a notch containing a filler material in intimate contact with the flyer plate. An adhesive means holds a ribbon explosive partially overlapping the notch in the flyer plate. A detonating means initiates the ribbon explosive that drives the flyer plate to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and effacing bonding, resulting in electron sharing linkups between the plates. An unbonded tab fractures at a base of the notch leaving a bond to an edge of the attached flyer plate
Permanent wire splicing by an explosive joining process
The invention is an apparatus and method for wire splicing using an explosive joining process. The apparatus consists of a prebent, U-shaped strap of metal that slides over prepositioned wires. A standoff means separates the wires from the strap before joining. An adhesive means holds two ribbon explosives in position centered over the U-shaped strap. A detonating means connects to the ribbon explosives. The process involves spreading strands of each wire to be joined into a flat plane. The process then requires alternating each strand in alignment to form a mesh-like arrangement with an overlapped area. The strap slides over the strands of the wires, and the standoff means is positioned between the two surfaces. The detonating means then initiates the ribbon explosives that drive the strap to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and collision bonding results in electron sharing linkups
We\u27re Here Because You Were There : Britain\u27s Black Population
The existence of a black population in Britain is the result of Britain’s imperialist history. The conquest of large parts of the world and their incorporation into a new world system dominated by Britain and other European nations not only created the economic basis of the capitalist system, but also set in motion massive movements of—and, indeed, constructions of—peoples. The creation of the African-American and African-Caribbean peoples are examples of this phenomenon: “We’re here because you were there.
Access to resources shapes maternal decision making: evidence from a factorial vignette experiment
The central assumption of behavioral ecology is that natural selection has shaped individuals with the capacity to make decisions that balance the fitness costs and benefits of behavior. A number of factors shape the fitness costs and benefits of maternal care, but we lack a clear understanding how they, taken together, play a role in the decision-making process. In animal studies, the use of experimental methods has allowed for the tight control of these factors. Standard experimentation is inappropriate in human behavioral ecology, but vignette experiments may solve the problem. I used a confounded factorial vignette experiment to gather 640 third-party judgments about the maternal care decisions of hypothetical women and their children from 40 female karo Batak respondents in rural Indonesia. This allowed me to test hypotheses derived from parental investment theory about the relative importance of five binary factors in shaping maternal care decisions with regard to two distinct scenarios. As predicted, access to resources--measured as the ability of a woman to provide food for her children--led to increased care. A handful of other factors conformed to prediction, but they were inconsistent across scenarios. The results suggest that mothers may use simple heuristics, rather than a full accounting for costs and benefits, to make decisions about maternal care. Vignettes have become a standard tool for studying decision making, but have made only modest inroads to evolutionarily informed studies of human behavior.The fieldwork was funded by the Arts & Humanities Research Council's (United Kingdom) "Culture and Mind" Project (http://
www.philosophy.dept.shef.ac.uk/culture&mind/)
Book review: Reproduction and adaptation: topics in human reproductive ecology
Reproduction and Adaptation: Topics in Human Reproductive Ecology. Edited by C.G. Mascie-Taylor and Lyliane Rosetta. Cambridge Studies in Biological and Evolutionary Anthropology, Vol. 59. Cambridge: Cambridge University Press. 2011. 282 pp. $99.00 (hardback). ISBN 978-0-521-50963-3
Gaps in Darwin's Initial Theory
This chapter focuses on shortcomings of Darwin's 1859 book, On the Origin of Species by Means of Natural Selection. These include a lack of a tenable mechanism of inheritance, inability to explain seemingly 'maladaptive traits', and the lack of transitional forms
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