2,138 research outputs found

    Bounding film drainage in common thin films

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    A review of thin film drainage models is presented in which the predictions of thinning velocities and drainage times are compared to reported values on foam and emulsion films found in the literature. Free standing films with tangentially immobile interfaces and suppressed electrostatic repulsion are considered, such as those studied in capillary cells. The experimental thinning velocities and drainage times of foams and emulsions are shown to be bounded by predictions from the Reynolds and the theoretical MTsR equations. The semi-empirical MTsR and the surface wave equations were the most consistently accurate with all of the films considered. These results are used in an accompanying paper to develop scaling laws that bound the critical film thickness of foam and emulsion films

    Doctor of Philosophy

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    dissertatio

    Voltage-controlled inversion of tunnel magnetoresistance in epitaxial Nickel/Graphene/MgO/Cobalt junctions

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    We report on the fabrication and characterization of vertical spin-valve structures using a thick epitaxial MgO barrier as spacer layer and a graphene-passivated Ni film as bottom ferromagnetic electrode. The devices show robust and scalable tunnel magnetoresistance, with several changes of sign upon varying the applied bias voltage. These findings are explained by a model of phonon-assisted transport mechanisms that relies on the peculiarity of the band structure and spin density of states at the hybrid graphene|Ni interface

    Optimal control of motorsport differentials

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    Modern motorsport limited slip differentials (LSD) have evolved to become highly adjustable, allowing the torque bias that they generate to be tuned in the corner entry, apex and corner exit phases of typical on-track manoeuvres. The task of finding the optimal torque bias profile under such varied vehicle conditions is complex. This paper presents a nonlinear optimal control method which is used to find the minimum time optimal torque bias profile through a lane change manoeuvre. The results are compared to traditional open and fully locked differential strategies, in addition to considering related vehicle stability and agility metrics. An investigation into how the optimal torque bias profile changes with reduced track-tyre friction is also included in the analysis. The optimal LSD profile was shown to give a performance gain over its locked differential counterpart in key areas of the manoeuvre where a quick direction change is required. The methodology proposed can be used to find both optimal passive LSD characteristics and as the basis of a semi-active LSD control algorithm

    Are Home Offices Feasible in a University?: Faculty Perceptions of a Home Office Experiment

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    This article examines faculty perceptions of how the new technologies of E-mail and voice mail that were widely adopted as a result of the home office experiment changed the ways of working and ways of thinking about what is important. The authors discussed both first- and second-level effects of communication technologies in three areas: (1) on faculty interaction both within the department and in the larger campus community, (2) on student/faculty interaction, and (3) on work styles and the ways faculty members think about their work. When the home office project was envisioned, the goal was to use communication technology to create a work environment in which faculty without an office on campus could come to campus simply to teach classes and perhaps occasionally attend meetings, while performing most other duties off campus. The project seemed more palatable to most faculty in the department and to administrators because it was temporary, but it did require all faculty members to move twice within a three year period

    Influence of Cultural Organization and Leadership on the Performance of Employees Mediated Job Satisfaction on District Health Department Mimika Papua

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    Cultural organizations have become the talk very interesting and very important in today's era. Not just in depth but in order to make changes continuously, making the competitive advantage and the ability to survive in an era of constantly changing. If an organization is not treated culture then the organization can certainly run into problems which ultimately affect the sustainability of the organization. Organizational culture becomes a key element of the changes that will be a huge impact for the working system of the organization. The purpose of this study is; (1) To examine and analyze organization with cultural influence, directly or indirectly through job satisfaction on the performance of employees at the Department of Health Government of Mimika District of Papua Province (2) To examine and analyze the effect leadership directly or indirectly through job satisfaction on the performance of employees at the Department of Health Government of Mimika District of Papua Province. (3) To examine and analyze the effect job satisfaction on the performance of employees at the Department of Health Government of Mimika District of Papua Province. Unit sample in this study were clerks in Mimika District Health Office. Respondents amounted to 259 employees, were taken using the convenient sampling method. Data were analyzed using Structural Equation Modeling (SEM) with the help of the program Analysis of Moment Structure (AMOS). The results showed that. The results showed that organizational culture and positive significant influence on employee performance both directly and indirectly through job satisfaction. It shows that when organizations are paying attention and make improvements to the organization's culture will directly be able to increase job satisfaction and indirectly affect employee performance. Leadership and positive significant effect on employee performance, both directly and indirectly through job satisfaction. It shows that the improvement of leadership in the organization will directly improve the performance of employees or indirectly through job satisfaction. Job satisfaction had positive significant influence on employee performance. This means that increasing employee satisfaction will be able to improve employee performance

    Ordering intermetallic alloys by ion irradiation: a way to tailor magnetic media

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    Combining He ion irradiation and thermal mobility below 600K, we both trigger and control the transformation from chemical disorder to order in thin films of an intermetallic ferromagnet (FePd). Kinetic Monte Carlo simulations show how the initial directional short range order determines order propagation. Magnetic ordering perpendicular to the film plane was achieved, promoting the initially weak magnetic anisotropy to the highest values known for FePd films. This post-growth treatment should find applications in ultrahigh density magnetic recording.Comment: 7 pages, 3 Figure
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