An experimental investigation of a two and a three-dimensional low speed turbulent boundary layer

Experimental studies of a two and a three-dimensional low speed turbulent boundary layer were conducted on the side wall of a boundary layer wind tunnel. The 20 ft. long test section, with a rectangular cross section measuring 17.5 in. x 46 in., produced a 3.5 in. thick turbulent boundary layer at a free stream Reynolds number. The three-dimensional turbulent boundary layer was produced by a 30 deg swept wing-like model faired into the side wall of the test section. Preliminary studies in the two-dimensional boundary layer indicated that the flow was nonuniform on the 46 in. wide test wall. The nonuniform boundary layer is characterized by transverse variations in the wall shear stress and is primarily caused by nonuniformities in the inlet damping screens

Case studies of outdoor testing and analysis of building components

The construction and development of the PASSYS/PASLINK outdoor test cells were funded by the European Commission, with the objective of providing high-quality test environments for quantifying the performance of passive solar building components. Over the years since the original test cells were commissioned, the initial concept for outdoor testing has been extended to include other test cell types. Significant improvements have been made to the experimental procedures and analysis techniques, and a broad range of components has been tested. This paper describes representative experiments that have been conducted using these highly controlled outdoor test environments, indicates some of the related analysis, and shows the type of information that can be obtained from such tests. It demonstrates the way in which component performance can be ascertained in the realistic external environment. The case studies chosen range from building component tests within EC research projects to commercial tests, and from conventional building components to novel integrated facade systems. They also include a large range of passive and active components. Each case study summarises the test component, the purpose of the test, details of the test configuration (period of test, instrumentation, etc.), results and analysis, and associated modelling and monitoring where appropriate. The paper concludes with an appraisal of the advantages and limitations of the test cells for the various component types

Needs and Opportunities for Agricultural Research from the Perspective of the CGIAR

Paper on the CGIAR's role in collaborative international agricultural research prepared by TAC Chairman Don Winkelmann for the first meeting of the Global Forum on Agricultural Research (GFAR) held during CGIAR International Centers Week, October-November 1996. The paper stressed the CGIAR's capacity for translating the research outputs of 'high science' into international public goods that addressed the needs of the poor and the imperatives of protecting the environment. Among all possible research choices, the CGIAR would emphasize topics that would make the most difference to the poor, and on which the CGIAR had a clear advantage.The paper was circulated as an input into GFAR discussions leading to a Declaration and Action Plan for Global Partnerships in Agricultural Research,. It was intended to provide insights on partnerships and collaboration from the perspective of the CGIAR

CGIAR Activities and Goals: Tracing the Connections

Issues in Agriculture no. 13 from the series "Issues in Agriculture" published by the CGIAR Secretariat

Stabilized high-power laser system for the gravitational wave detector advanced LIGO

An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments

Social acts and social systems: Community as metaphor

The community metaphor currently dominates much of the thinking in educational theory and pedagogy, especially in the field of composition and rhetoric. This study critiques the community metaphor through a tripartite analysis of student- sand teacher-generated metaphors. Two textual levels of metaphors-in-use are considered: grammatical--semantic metaphors and lexical metaphors. A functional linguistic analysis demonstrates the thoroughly heteroglossic nature of language in classroom talk and text. This article contends it would be more useful for teachers to proceed from a collectivity metaphor as a way to capture the dynamic nature of language-in-use. Subsequently, both students and teachers can be more attentive to the ways in which they define themselves, through metaphor, as a group-in-process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29509/1/0000596.pd