Student Learning on Faculty-Led Study Abroad: A Qualitative Study of Stakeholder Views

University of Minnesota Ph.D. dissertation. 2019. Major: Organizational Leadership, Policy, and Development. Advisor: Deanne Magnusson. 1 computer file (PDF); 243 pages.This is a study of intercultural learning and teaching through study abroad programs at one four-year public higher education institution in the United States. The purpose of this study is to determine stakeholder views of factors influencing student learning in faculty-led study abroad programs. Using a constructivist grounded theory methodology and qualitative methods, the researcher explored with faculty study abroad leaders and returned study abroad students their experiences with intercultural learning, and from the collected data, constructed themes related the two research questions. The first question was: 1) In what ways do student and faculty stakeholders describe the student learning outcomes achieved through participation in faculty-led study abroad programs? Themes related to student learning outcomes include applied learning of course content, professional development, comparative understanding of cultures, personal growth, and understanding of identity-related issues. The second question was: 2) What do faculty and students view as factors influencing student learning outcomes in faculty-led study abroad programs? Key factors suggested by students and faculty related to student-centered teaching and learning, instructor expertise, student behaviors, and institutional support of faculty. Several implications for pedagogy and professional practice in the field of study abroad also emerged from this study. These related to faculty and student mutual definition of student learning outcomes; incorporation of authentic student-centered pedagogical practices, and related faculty professional development. Study findings also illustrate the need for institutional support for faculty engagement in study abroad programs

Electro-optic time profile monitors for femtosecond electron bunches at the soft x-ray free-electron laser FLASH

Precise measurements of the temporal profile of ultrashort electron bunches are of high interest for the optimization and operation of ultraviolet and x-ray free-electron lasers. The electro-optic (EO) technique has been applied for a single-shot direct visualization of the time profile of individual electron bunches at FLASH. This paper presents a thorough description of the experimental setup and the results. An absolute calibration of the EO technique has been performed utilizing simultaneous measurements with a transverse-deflecting radio-frequency structure that transforms the longitudinal bunch charge distribution into a transverse streak. EO signals as short as 60 fs (rms) have been observed using a gallium-phosphide (GaP) crystal, which is a new record in the EO detection of single electron bunches and close to the physical limit imposed by the EO material properties. The data are in quantitative agreement with a numerical simulation of the EO detection process

Benchmarking of electro-optic monitors for femtosecond electron bunches

The longitudinal profiles of ultrashort relativistic electron bunches at the soft x-ray free-electron laser FLASH have been investigated using two single-shot detection schemes: an electro-optic (EO) detector measuring the Coulomb field of the bunch and a radio-frequency structure transforming the charge distribution into a transverse streak. A comparison permits an absolute calibration of the EO technique. EO signals as short as 60 fs (rms) have been observed, which is a new record in the EO detection of single electron bunches and close to the limit given by the EO material properties

Single-shot longitudinal bunch profile measurements at FLASH using electro-optic detection:experiment, simulation, and validation

At the superconducting linac of FLASH at DESY, we have installed an electro-optic (EO) experiment for single- shot, non-destructive measurements of the longitudinal electric charge distribution of individual electron bunches. The time profile of the electric bunch field is electro- optically encoded onto a chirped titanium-sapphire laser pulse. In the decoding step, the profile is retrieved either from a cross-correlation of the encoded pulse with a 30 fs laser pulse, obtained from the same laser (electro- optic temporal decoding, EOTD), or from the spectral intensity of the transmitted probe pulse (electro-optic spectral decoding, EOSD). At FLASH, the longitudinally compressed electron bunches have been measured during FEL operation with a resolution of better than 50 fs. The electro-optic process in gallium phosphide was numerically simulated using as input data the bunch shapes determined with a transverse-deflecting RF structure. In this contribution, we present electro-optically measured bunch profiles and compare them with the simulation

A sub-50 femtosecond bunch arrival time monitor system for

Abstract A bunch arrival time monitor using the future laser based synchronization system at FLASH has been developed. The signal of a beam pick-up with several GHz bandwidth is sampled by a sub-ps laser pulse using a broadband electro-optical modulator. Bunch arrival time deviations are converted into amplitude modulations of the sampling laser pulses which are then detected by a photo-detector. A resolution of 30 fs could be reached with the capability towards sub-10 fs level. In this paper we describe the design of the optical system and present recent results

Evaluation of a Kinematically-Driven Finite Element Footstrike Model

A dynamic finite element model of a shod running footstrike was developed and driven with six degree of freedom foot segment kinematics determined from a motion capture running trial. Quadratic tetrahedral elements were used to mesh the footwear components with material models determined from appropriate mechanical tests. Model outputs were compared to experimental high speed video (HSV) footage, vertical ground reaction force (GRF) and centre of pressure (COP) excursion to determine whether such an approach is appropriate for the development of athletic footwear. Although unquantified, good visual agreement to the HSV footage was observed but significant discrepancies were found between the model and experimental GRF and COP readings (9% and 61% of model readings outside of the mean experimental reading ± 2 standard deviations respectively). Model output was also found to be highly sensitive to input kinematics with a 120% increase in maximum GRF observed when translating the force platform 2 mm vertically. Whilst representing an alternative approach to existing dynamic finite elements footstrike models, loading highly representative of an experimental trial was not found to be achievable when employing exclusively kinematic boundary conditions. This significantly limits the usefulness of employing such an approach in the footwear development process