DRUM - Digital Repository at the University of Maryland

DRUM collects, preserves, and provides public access to the scholarly output of the university. Faculty and researchers can upload research products for rapid dissemination, global visibility and impact, and long-term preservation.

Submit to DRUM

Submit to DRUM

To submit an item to DRUM, login using your UMD credentials. Then select the "Submit Item to DRUM" link in the navigation bar. View DRUM policies and submission guidelines.
Equitable Access Policy

Equitable Access Policy

The University of Maryland Equitable Access Policy provides equitable, open access to the University's research and scholarship. Faculty can learn more about what is covered by the policy and how to deposit on the policy website.
Theses and Dissertations

Theses and Dissertations

DRUM includes all UMD theses and dissertations from 2003 forward.

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UM Community-managed Collections

Recent Submissions

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    Open Access Policy Bulk Collection Toolkit
    (2025) Ingalls, Allison; Wilson, Michelle
    This toolkit, developed in the Fall 2025 semester, facilitates the collection of eligible materials to increase compliance with a campus open access policy. The toolkit is designed to support individuals outside of the libraries and/or repository staff with collecting materials directly from publishing faculty members. The toolkit includes: -A short presentation (slides) on the OA policy and its benefits to researchers -A graphic representation of the collection workflow -A checklist for the collection process with built in timeline and tracking -A template for bulk deposit based on the UMD DSpace metadata schema -A set of draft email templates for communicating with faculty -A presentation on this toolkit and the pilot initiative that it supported was made at the Northeast Institutional Repositories Day (NIRD) on December 5, 2025: https://zenodo.org/records/17941001
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    Data Combination: Interferometry and Single-dish Imaging in Radio Astronomy
    (Publications of the Astronomical Society of the Pacific, 2023) Plunkett, Adele; Hacar, A.; Moser-Fischer, Lydia; Petry, D.; Teuben, Peter; Pingel, M., N.; Kunneriath, D.; Takagi, Toshinobu; Miyamoto, Yusuke; Moravec, Emily; Suri, S.; Hess, M., Kelley; Hoffman, Melissa; Mason, Brian
    Abstract Modern interferometers routinely provide radio-astronomical images down to subarcsecond resolution. However, interferometers filter out spatial scales larger than those sampled by the shortest baselines, which affects the measurement of both spatial and spectral features. Complementary single-dish data are vital for recovering the true flux distribution of spatially resolved astronomical sources with such extended emission. In this work, we provide an overview of the prominent available methods to combine single-dish and interferometric observations. We test each of these methods in the framework of the CASA data analysis software package on both synthetic continuum and observed spectral data sets. We develop a set of new assessment tools that are generally applicable to all radio-astronomical cases of data combination. Applying these new assessment diagnostics, we evaluate the methods’ performance and demonstrate the significant improvement of the combined results in comparison to purely interferometric reductions. We provide combination and assessment scripts as add-on material. Our results highlight the advantage of using data combination to ensure high-quality science images of spatially resolved objects.
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    Improving quantitative ventifact analysis for climate investigations using the Dyngjusandur sandsheet in Iceland as a planetary analogue
    (Journal of the Geological Society, 2025) Hudziak, Xavier, Samuel; Peate, Ukstins, Ingrid; Peate, D.W.; Whelley, P.; Scheidt, P., S.; Hamilton, W., Christopher
    We use the Dyngjusandur sandsheet, Iceland, as a testbed to assess the type and number of measurements required to accurately represent ventifact orientations and extract palaeowind information through a statistical evaluation of the differences between photogrammetric based and in situ measurements of ventifact feature orientations. Forty representative ventifacts were selected for in situ measurement, 20 of which were imaged for photogrammetric analysis to produce oriented and scaled virtual 3D models. An additional set of measurements were made on the ‘synthetic’ models to allow for statistical assessment of erosional feature orientation. Despite the similarity between the photogrammetric (1145 measurements) and the in situ datasets (500 measurements), there are small but significant differences in mean feature orientation that become more pronounced as sample size is reduced. Results indicate that in situ and photogrammetric methods of measuring feature orientation are comparable (to within 2° ± 2° at 1 σ ( n = 20) for inferring palaeowind directions), but photogrammetric analyses require less time for data acquisition (by a factor of 0.36–0.66) and yield over five times (5.16 times) as many measurements per ventifact, with additional advantages of being able to examine digital objects under different illumination conditions and magnifications, and from angles that are otherwise not possible in the field.
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    Exploring the Solar Wind?Planetary Interaction at Mars: Implication for Magnetic Reconnection
    (Journal of Geophysical Research Space Physics, 2023) Bowers, F., C.; DiBraccio, A., G.; Slavin, A., J.; Gruesbeck, J.; Weber, Tristan; Xu, Shaosui; Romanelli, Norberto; Harada, Yuki
    Abstract The Martian crustal magnetic anomalies present a varied, asymmetric obstacle to the imposing draped interplanetary magnetic field (IMF) and solar wind plasma. Magnetic reconnection, a ubiquitous plasma phenomenon responsible for transferring energy and changing magnetic field topology, has been observed throughout the Martian magnetosphere. More specifically, reconnection can occur as a result of the interaction between crustal fields and the IMF, however, the global implications and changes to the overall magnetospheric structure of Mars have yet to be fully understood. Here, we present an analysis to determine these global implications by investigating external conditions that favor reconnection with the underlying crustal anomalies at Mars. To do so, we plot a map of the crustal anomalies' strength and orientation compiled from magnetic field data collected throughout the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Then, we create “shear maps” which calculate and plot the angle of shear between the crustal fields and a chosen external field orientation. From there we define a “shear index” to quantify the susceptibility of a region to undergo reconnection based on a given overlaid, external field orientation and the resulting shear map for that region. We demonstrate that the shear analysis technique augments analysis of local reconnection events and suggests southward IMF conditions should favor dayside magnetic reconnection on a more global scale at Mars.
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    VERTICO V: The environmentally driven evolution of the inner cold gas discs of Virgo cluster galaxies
    (Publications of the Astronomical Society of Australia, 2023) Watts, B., Adam; Cortese, L.; Catinella, Barbara; Brown, Toby; Wilson, D., C.; Zabel, Nikki; Roberts, Ian; Davis, A., Timothy; Thorp, Mallory; Chung, Aeree; Stevens, H., R., Adam; Ellison, L., Sara; Spekkens, Kristine; Parker, C., Laura; Bahé, M, Yannick; Villanueva, Vicente; Jiménez-Donaire, J., María; Bisaria, Dhruv; Boselli, A.; Bolatto, D., Alberto; Lee, Bumhyun
    Abstract The quenching of cluster satellite galaxies is inextricably linked to the suppression of their cold interstellar medium (ISM) by environmental mechanisms. While the removal of neutral atomic hydrogen (H i ) at large radii is well studied, how the environment impacts the remaining gas in the centres of galaxies, which are dominated by molecular gas, is less clear. Using new observations from the Virgo Environment traced in CO survey (VERTICO) and archival H i data, we study the H i and molecular gas within the optical discs of Virgo cluster galaxies on 1.2-kpc scales with spatially resolved scaling relations between stellar ( $Sigma_{star}$ ), H i ( $Sigma_{text{H},{smalltext{I}}}$ ), and molecular gas ( $Sigma_{text{mol}}$ ) surface densities. Adopting H i deficiency as a measure of environmental impact, we find evidence that, in addition to removing the H i at large radii, the cluster processes also lower the average $Sigma_{text{H},{smalltext{I}}}$ of the remaining gas even in the central $1.2,$ kpc. The impact on molecular gas is comparatively weaker than on the H i , and we show that the lower $Sigma_{text{mol}}$ gas is removed first. In the most H i -deficient galaxies, however, we find evidence that environmental processes reduce the typical $Sigma_{text{mol}}$ of the remaining gas by nearly a factor of 3. We find no evidence for environment-driven elevation of $Sigma_{text{H},{smalltext{I}}}$ or $Sigma_{text{mol}}$ in H i -deficient galaxies. Using the ratio of $Sigma_{text{mol}}$ -to- $Sigma_{text{H},{smalltext{I}}}$ in individual regions, we show that changes in the ISM physical conditions, estimated using the total gas surface density and midplane hydrostatic pressure, cannot explain the observed reduction in molecular gas content. Instead, we suggest that direct stripping of the molecular gas is required to explain our results.