251 research outputs found

    What Works? A Critique of Appreciative Inquiry as a Research Method/ology

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    Appreciative Inquiry (AI) has gained prominence as an organizational development approach. For over 15 years, it has had varied use in higher education research as a methodology and as a collection of methods. Perhaps the most consistently used, yet most criticized, aspect of AI is the positive stance that its adherents adopt. In this chapter, we survey the prevalence and use of AI, both in the wider literature and in higher education research. We offer our own case study to illustrate the practicalities of employing it and discuss our findings. We suggest that educational researchers are overlooking relevant AI research published within other disciplines; that our own and other case stories can provide guidance for the use of AI in academic contexts; and that AI’s collaborative and positive standpoint has potential as a research methodology influencing policy

    Wear of Fluorapatite Single Crystals : VI. Influence of Multiple-Pass Sliding on Surface Failure

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    The influence of multiple-pass sliding on the surface failure of fluorapatite single crystals was evaluated. The surface and subsurface damage on the basal plane of fluorapatite was accelerative, rather than additive. Damage was more severe for sliding in opposite directions than for two traversals in the same direction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66476/2/10.1177_00220345730520050601.pd

    Wear of Fluorapatite Single Crystals : IV. Influence of Sliding Direction on Frictional Behavior and Surface Failure

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    Frictional anisotropy of the basal plane of natural fluorapatite single crystals was observed ; the coefficient of friction (β) in the [2110] direction (β = 0.217) was approximately 12% higher than that in the [0110] direction (β = 0.193). The load at which the ductile-to-brittle transition occurred (Ω) was significantly higher in the [2110] direction (Ω = 77 gm) than in the [0110] direction (Ω = 15 gm). A mechanism is proposed involving the maximum normal stress and probable cleavage planes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67194/2/10.1177_00220345730520050401.pd

    Tribological performance of novel Nickel-based composite coatings with lubricant particles

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    Abstract The present study is focused on the evaluation of the tribological performance of novel Ni/hBN and Ni/WS2 composite coatings electrodeposited from an additive-free Watts bath with the assistance of ultrasound. Lubricated and non-lubricated scratch tests were performed on both novel composite coatings and on standard Ni deposits used as a benchmark coating to have an initial idea of the effect of the presence of particles within the Ni matrix. Under lubricated conditions, the performance of the Ni/hBN composite coating was very similar to the benchmark Ni coating, whereas the Ni/WS2 behaved quite differently, as the latter did not only show a lower coefficient of friction, but also prevented the occurrence of stick-slip motion that was clearly observed in the other coatings. Under non-lubricated conditions, whereas the tribological performance of the Ni/hBN composite coating was again very similar to that of the benchmark Ni coating, the Ni/WS2 composite coatings again showed a remarkable enhancement, as the incorporation of the WS2 particles into the Ni coating not only resulted in a lower coefficient of friction, but also in the prevention of coating failure

    Theory of differential inclusions and its application in mechanics

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    The following chapter deals with systems of differential equations with discontinuous right-hand sides. The key question is how to define the solutions of such systems. The most adequate approach is to treat discontinuous systems as systems with multivalued right-hand sides (differential inclusions). In this work three well-known definitions of solution of discontinuous system are considered. We will demonstrate the difference between these definitions and their application to different mechanical problems. Mathematical models of drilling systems with discontinuous friction torque characteristics are considered. Here, opposite to classical Coulomb symmetric friction law, the friction torque characteristic is asymmetrical. Problem of sudden load change is studied. Analytical methods of investigation of systems with such asymmetrical friction based on the use of Lyapunov functions are demonstrated. The Watt governor and Chua system are considered to show different aspects of computer modeling of discontinuous systems

    Policy Issues in NEG Models: Established Results and Open Questions

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    This paper provides a non-technical overview of NEG models dealing with policy issues. Considered policy measures include alternative categories of public expenditure, international tax competition, unilateral actions of protection/liberalisation, and trade agreements. The implications of public intervention in two-region NEG models are discussed by unfolding the impact of policy measures on agglomeration/dispersion forces. Results are described in contrast with those obtained in standard non-NEG theoretical models. The high degree of abstraction limits the applicability of NEG models to real world policy issues. We discuss in some detail two extensions of NEG models to reduce this applicability gap: the cases of multi-regional frameworks and firm heterogeneity

    Wear of dental enamel,

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    Teeth wear for a number of reasons. One of the causes for wear is the use of abrasive tooth pastes. A study is reported in which enamel was damaged by single pass sliding of a diamond indenter. In single crystals of fluorapatite, wear occurs by flaking out of chips of material and severely fractured substrate is left behind. On the other hand teeth are made of small rods of polycrystalline hydroxyapatite of the order of 5 [mu]m in diameter oriented perpendicular to the tooth surface. This rod structure of human teeth prevents large scale flaking out of material. Apparently the subsurface cracks do not extend from one rod to the other so that subsequent passes do not result in severe wear. Small abrasive particles may do considerable damage to rods, but the overall effect is small. Large abrasive particles with high loads cause separation of rods, and cracks appear to propagate but without severe permanent damage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33951/1/0000220.pd

    Frictional behavior and surface failure of dental feldspathic porcelain

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    Wear and frictional behavior of dental feldspathic porcelain was investigated in air and in water with a single-pass sliding technique. As-glazed, gold-coated and chromium-coated porcelains were tested. Friction of the as-glazed porcelain was higher in water and surface damage was more extensive than in air. Gold-coating reduced the friction but had no apparent effect on the mode of surface failure in these environments. Chromium-coating did not reduce the friction at higher loads but did reduce the extent of surface damage when compared with the as-glazed material.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22137/1/0000566.pd
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