23,102 research outputs found

    Laser Doppler Velocimetry Workshop

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    The potential of laser Doppler velocimetry as a technique for use in mapping flows in the several fluid systems under development for doing research on low-gravity processes, is investigated. Laser Doppler velocimetry techniques, equipment, and applications are summarized

    Collimated beam manifold with the number of output beams variable at a given output angle

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    An optical manifold is described which transforms a collimated beam, such as a laser beam, into a plurality of parallel beams having uniform intensity or having a desired intensity ratio. The manifold comprises an optical substrate coated on its rear surface with a fully reflective layer and on its front surface with a partially reflecting layer having a reflectivity gradient. An input collimated beam entering the rear surface and impinging on the front surface is reflected, multiply between the front and rear surfaces producing a plurality of parallel beams that emerge from the front surface. The intensities of the emerging beams have a relationship that depends on the reflectivity of the front surface at the points where the beams emerge. By properly selecting the reflectivity gradient, the emerging beams have uniform intensity or a desired intensity ratio

    Dual laser optical system and method for studying fluid flow

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    A dual laser optical system and method is disclosed for visualization of phenomena in transport substances which induce refractive index gradients such as fluid flow and pressure and temperature gradients in fluids and gases. Two images representing mutually perpendicular components of refractive index gradients may be viewed simultaneously on screen. Two lasers having wave lengths in the visible range but separated by about 1000 angstroms are utilized to provide beams which are collimated into a beam containing components of the different wave lengths. The collimated beam is passed through a test volume of the transparent substance. The collimated beam is then separated into components of the different wave lengths and focused onto a pair of knife edges arranged mutually perpendicular to produce and project images onto the screen

    Conceptual development of the Laser Beam Manifold (LBM)

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    The laser beam manifold, a device for transforming a single, narrow, collimated beam of light into several beams of desired intensity ratios is described. The device consists of a single optical substrate with a metallic coating on both optical surfaces. By changing the entry point, the number of outgoing beams can be varied

    Double window viewing chamber assembly

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    A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter

    Analysis framework for the interaction between lean construction and building information modelling

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    Building with Building Information Modelling (BIM) changes design and production processes. But can BIM be used to support process changes designed according to lean production and lean construction principles? To begin to answer this question we provide a conceptual analysis of the interaction of lean construction and BIM for improving construction. This was investigated by compiling a detailed listing of lean construction principles and BIM functionalities which are relevant from this perspective. These were drawn from a detailed literature survey. A research framework for analysis of the interaction between lean and BIM was then compiled. The goal of the framework is to both guide and stimulate research; as such, the approach adopted up to this point is constructive. Ongoing research has identified 55 such interactions, the majority of which show positive synergy between the two

    Cosmic rays in early star-forming galaxies and their effects on the interstellar medium

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    Galaxies at high redshifts with strong star formation are sources of high-energy cosmic rays. These cosmic rays interact with the baryon and radiation fields of the galactic environment via photo-pair, photo-pion and proton-proton processes to produce charged and neutral pions, neutrons and protons. The cosmic rays thereby deposit energy into the interstellar medium (ISM) as they propagate. We show how energy transport and deposition by ultra high-energy cosmic rays is regulated by the evolution of the galaxy, in particular by the development of the galactic magnetic field. We show how the particle-driven energy deposition can influence the thermal evolution of the host and its surroundings. Using a parametric protogalaxy model, we calculate the heating effect on the ISM as the cosmic rays are increasingly confined by the magnetic evolution of the galaxy.Comment: 8 pages, 2 figures; Proceedings of the 35th International Cosmic Ray Conference (ICRC2017), 10-20 July 2017, Bexco, Busan, Korea - PoS(ICRC2017)28

    A Conceptual Analysis of Relational Contracts in Agribusiness Supply Chains: The Case of the Sugar Industry in Swaziland

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    This study examines the nature of the relationship between cane growers and millers and how it affects cane growersÂ’ perceptions of the value added in the sugar supply chain. Drawing from relational exchange theory, the study utilised the perceptions of 124 smallholder cane growers in the Swaziland sugar industry. Factors measured in terms of a likert type scale were used to measure each relational construct within the miller-grower contract relationship. The unpacks the trust relationship between large agribusiness companies and smallholder out growers, and shows that relationships characterised by social factors like trust, commitment, and cooperation enhance mutual benefit and quality relationships between parties. This study found that farmers perceive an element of opportunistic behaviour and a lack of cooperation by millers and therefore have limited trust in the millers. Consequently it was also found that satisfaction by cane growers on their relationship with millers has a positive relationship with their level of trust, level of commitment, relative dependence, perception of opportunistic behaviour by millers and perceived cooperation between themselves and the millers. The results point to a number of aspects both growers and millers need to attend to which could contribute to improved relationship and in turn efficiency and returns in the sugar industry in Swaziland.Agribusiness,
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