Classification of journal surfaces using surface topography parameters and software methods to compensate for stylus geometry

Measurements made with a stylus surface tracer which provides a digitized representation of a surface profile are discussed. Parameters are defined to characterize the height (e.g., RMS roughness, skewness, and kurtosis) and length (e.g., autocorrelation) of the surface topography. These are applied to the characterization of crank shaft journals which were manufactured by different grinding and lopping procedures known to give significant differences in crank shaft bearing life. It was found that three parameters (RMS roughness, skewness, and kurtosis) are necessary to adequately distinguish the character of these surfaces. Every surface specimen has a set of values for these three parameters. They can be regarded as a set coordinate in a space constituted by three characteristics axes. The various journal surfaces can be classified along with the determination of a proper wavelength cutoff (0.25 mm) by using a method of separated subspace. The finite radius of the stylus used for profile tracing gives an inherent measurement error as it passes over the fine structure of the surface. A mathematical model is derived to compensate for this error

Aggregation of frictional particles due to capillary attraction

Capillary attraction between identical millimeter sized spheres floating at a liquid-air interface and the resulting aggregation is investigated at low Reynolds number. We show that the measured capillary forces between two spheres as a function of distance can be described by expressions obtained using the Nicolson approximation at low Bond numbers for far greater particle sizes than previously assumed. We find that viscous hydrodynamics interactions between the spheres needs to be included to describe the dynamics close to contact. We then consider the aggregates formed when a third sphere is added after the initial two spheres are already in contact. In this case, we find that linear superposition of capillary forces describes the observed approach qualitatively but not quantitatively. Further, we observe an angular dependence of the structure due to a rapid decrease of capillary force with distance of separation which has a tendency to align the particles before contact. When the three particles come in contact, they may preserve their shape or rearrange to form an equilateral triangle cluster - the lowest energy state - depending on the competition between attraction between particles and friction. Using these observations, we demonstrate that a linear particle chain can be built from frictional particles with capillary attraction.Comment: accepted for Physical Review

A model of the dynamics of boundary film formation

The dynamics of formation and loss of the boundary films formed during sliding on steel surfaces were investigated over a range of temperature. Tests are performed on a cylinder-on-disk machine using mineral oil with various concentrations of zinc dialkyldithiophosphate (ZDP). The thickness and refractive index of the boundary films during step load test were monitored in situ with an ellipsometer, and the composition of the films was analyzed by X-ray photoelectron spectroscopy (XPS). As temperature increases, chemical reactivity increases the film formation rate, while the film removal rate increases owing to (a) the decrease of durability of the boundary film material and (b) the reduction of hydrodynamic fluid film thickness due to decreasing viscosity of the lubricant. There is a balance between these two competing mechanisms, and this balance is reflected in the boundary film thickness. The boundary films consist of a film of oxide and metallic compound (OMM) covered by an organo-iron compound (OIC). Their relative effectiveness in preventing scuffing depends on temperature and composition. In particular, the OIC is effective in reducing wear of the opposing surfaces by covering the OMM.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31341/1/0000251.pd

Reflections: OD or Not OD that is the Question! A Constructivist's Thoughts on the Changing Nature of Change

The landscape of organization development (OD) has changed significantly over the last several decades. This article provides a broad commentary on these changes. In particular, it offers a critique of 'current OD' in terms of the marginalization of materiality in discourse-based OD techniques and the neglect of problem-centred, diagnostic approaches in favour of solution-driven, emergent approaches. The future of OD is also explored in relation to the scope for meaningful 'bottom-up OD' (i.e. employee-instigated change) and 'outside-in OD' (i.e. involving a range of non-organizational stakeholders). © 2013 Taylor & Francis

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

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

Neighborhood Poverty and Control of HIV, Hypertension, and Diabetes in the Women’s Interagency HIV Study

Neighborhoods with high poverty rates have limited resources to support residents’ health. Using census data, we calculated the proportion of each Women’s Interagency HIV Study participant’s census tract (neighborhood) living below the poverty line. We assessed associations between neighborhood poverty and (1) unsuppressed viral load [VL] in HIV-seropositive women, (2) uncontrolled blood pressure among HIV-seropositive and HIV-seronegative hypertensive women, and (3) uncontrolled diabetes among HIV-seropositive and HIV-seronegative diabetic women using modified Poisson regression models. Neighborhood poverty was associated with unsuppressed VL in HIV-seropositive women (> 40% versus ≤ 20% poverty adjusted prevalence ratio (PR), 1.42; 95% confidence interval (CI) 1.04–1.92). In HIV-seronegative diabetic women, moderate neighborhood poverty was associated with uncontrolled diabetes (20–40% versus ≤ 20% poverty adjusted PR, 1.75; 95% CI 1.02–2.98). Neighborhood poverty was associated with neither uncontrolled diabetes among HIV-seropositive diabetic women, nor uncontrolled hypertension in hypertensive women, regardless of HIV status. Women living in areas with concentrated poverty may need additional resources to control health conditions effectively

How being appreciative creates change – theory in practice from health and social care in Scotland

This paper develops understanding of appreciative action research that generates curiosity and motivation as a better platform for collaborative change. Blending theory and practice it draws on the example of the My Home Life leadership programme in Scotland that explores the concepts and approaches of ‘Caring Conversations’ and ‘playful provocation’ in care homes for older people. The paper shows how they expand notions of appreciation and help people to deepen inquiry, explore values, acknowledge and express emotion without dispute or judgement, articulate tacit knowledge and give voice to things previously thought to be ‘unsayable’. We explore how these generative approaches act as a powerful positive ‘disruption’ that brings existing relationships to life, supports a positive attitude to risk-taking and helps to devise new approaches to the local design and testing of approaches to problems. Ultimately these approaches play an important part in developing understanding of how to do appreciative action research to enhance relationships and more strengths or assets-based and collaborative ways of working and so, to develop new possibilities for changing social systems and a more future-making orientation to action research