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Description

We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant azimuthal modes. Without external magnetic field flows are stable and pro-grade with respect to the rotation of the inner cylinder. More complex behaviors can

We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant azimuthal modes. Without external magnetic field flows are stable and pro-grade with respect to the rotation of the inner cylinder. More complex behaviors can arise when an axial or a transverse magnetic field is applied. Depending on the direction and strength of the field, multi-stable wavy states and bifurcations can occur. We uncover the phenomenon of flow pattern reversal as the strength of the magnetic field is increased through a critical value. In between the regimes of pro-grade and retrograde flow rotations, standing waves with zero angular velocities can emerge. A striking finding is that, under a transverse magnetic field, a second reversal in the flow pattern direction can occur, where the flow pattern evolves into pro-grade rotation again from a retrograde state. Flow reversal is relevant to intriguing phenomena in nature such as geomagnetic reversal. Our results suggest that, in ferrofluids, flow pattern reversal can be induced by varying a magnetic field in a controlled manner, which can be realized in laboratory experiments with potential applications in the development of modern fluid devices.

ContributorsAltmeyer, Sebastian (Author) / Do, Younghae (Author) / Lai, Ying-Cheng (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2015-12-21
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Description

We investigate fundamental nonlinear dynamics of ferrofluidic Taylor-Couette flow - flow confined be-tween two concentric independently rotating cylinders - consider small aspect ratio by solving the ferro-hydrodynamical equations, carrying out systematic bifurcation analysis. Without magnetic field, we find steady flow patterns, previously observed with a simple fluid, such as those

We investigate fundamental nonlinear dynamics of ferrofluidic Taylor-Couette flow - flow confined be-tween two concentric independently rotating cylinders - consider small aspect ratio by solving the ferro-hydrodynamical equations, carrying out systematic bifurcation analysis. Without magnetic field, we find steady flow patterns, previously observed with a simple fluid, such as those containing normal one- or two vortex cells, as well as anomalous one-cell and twin-cell flow states. However, when a symmetry-breaking transverse magnetic field is present, all flow states exhibit stimulated, finite two-fold mode. Various bifurcations between steady and unsteady states can occur, corresponding to the transitions between the two-cell and one-cell states. While unsteady, axially oscillating flow states can arise, we also detect the emergence of new unsteady flow states. In particular, we uncover two new states: one contains only the azimuthally oscillating solution in the configuration of the twin-cell flow state, and an-other a rotating flow state. Topologically, these flow states are a limit cycle and a quasiperiodic solution on a two-torus, respectively. Emergence of new flow states in addition to observed ones with classical fluid, indicates that richer but potentially more controllable dynamics in ferrofluidic flows, as such flow states depend on the external magnetic field.

ContributorsAltmeyer, Sebastian (Author) / Do, Younghae (Author) / Lai, Ying-Cheng (Author)
Created2017-01-06
Description
A presentation describing technical work, community reaction and publicity associated with an online collection of Arizona Japanese-American internment camp newsletters and related archival materials developed in 2017. The presentation was given at the Arizona Library Association conference in October 2017 and this revised version was presented at the Arizona Archives

A presentation describing technical work, community reaction and publicity associated with an online collection of Arizona Japanese-American internment camp newsletters and related archival materials developed in 2017. The presentation was given at the Arizona Library Association conference in October 2017 and this revised version was presented at the Arizona Archives Summit on February 1, 2018.
ContributorsSpindler, Rob (Author)
Created2018-01-18
Description

Materials produced for the workshop hosted by the Humane Cities Initiative, Institute for Humanities Research, Arizona State University. Participants were sent this package of archival materials and links to brief online sources for advance readings. Also enclosed are PDF renderings of introductory powerpoint files by Spindler and Pagan, and an

Materials produced for the workshop hosted by the Humane Cities Initiative, Institute for Humanities Research, Arizona State University. Participants were sent this package of archival materials and links to brief online sources for advance readings. Also enclosed are PDF renderings of introductory powerpoint files by Spindler and Pagan, and an audio recording of the discussion joined in progress.

ContributorsSpindler, Rob (Compiler, Author) / Pagán, Eduardo Obregón, 1960- (Author)
Created2018-03-13
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Description

Presentation slides regarding the history of Victory Village, the trailer park built in 1945-46 to provide housing for WWII Veterans and their families at Arizona State University's Tempe campus. A presentation of research from University Archives records conducted in the summer of 2018. The presentation was videotaped as a lecture

Presentation slides regarding the history of Victory Village, the trailer park built in 1945-46 to provide housing for WWII Veterans and their families at Arizona State University's Tempe campus. A presentation of research from University Archives records conducted in the summer of 2018. The presentation was videotaped as a lecture for Professor Volker Benkert's online World War II history class.

ContributorsSpindler, Rob (Author)
Created2019-09-30
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Description

Powerpoint slides from Spindler's presentation at the 56th annual Arizona History Convention in Tucson, Arizona, April 24th, 2015. Details of the 1993-1995 U.S. District Court orders directing the corporate archives to Arizona State University and ASU's efforts to recover information from an obsolete digital imaging system are presented.

ContributorsSpindler, Rob (Author)
Created2015-04-24
DescriptionPowerpoint slides, audio clips and transcriptions from the presentation describing the work of Lincoln and Eleanor Ragsdale and civil rights actions at Phoenix from 1963-1964.
ContributorsSpindler, Rob (Author)
Created2017-02-18
Description

This research study will discover and evaluate information about existing crowdsourcing or participatory archives projects devoted to archival description, indexing or transcription. Many related projects that use crowdsourcing for collecting archival materials from the public are not specifically addressed here. In this research, the author has specifically sought evaluative information

This research study will discover and evaluate information about existing crowdsourcing or participatory archives projects devoted to archival description, indexing or transcription. Many related projects that use crowdsourcing for collecting archival materials from the public are not specifically addressed here. In this research, the author has specifically sought evaluative information about exemplary projects that can lead to useful specifications for a participatory archives system at Arizona State University Libraries.

ContributorsSpindler, Rob (Author)
Created2014-06-30
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Description

Presentation slides describing an Arizona Centennial project to build a digital library and facilitate community discussion about why people came to Arizona, why they stayed, and why they left. Presentation was made at Friendship Village, Tempe AZ, November 2011.

ContributorsSpindler, Rob (Author)
Created2011-10-31
Description

The Task Force of thirty faculty members and academic professionals was charged by the University Libraries and the Graduate College to "examine the potential for implementing a university program for Electronic Theses and Dissertations (ETDs). The Task Force was specifically asked to collect information about existing programs elsewhere, identify ASU

The Task Force of thirty faculty members and academic professionals was charged by the University Libraries and the Graduate College to "examine the potential for implementing a university program for Electronic Theses and Dissertations (ETDs). The Task Force was specifically asked to collect information about existing programs elsewhere, identify ASU graduate programs that could host pilot programs and prepare a comprehensive white paper..." with a recommended plan for implementation.

ContributorsSpindler, Rob (Compiler) / Losse, Deborah (Compiler)
Created2001-05-01