10,761 research outputs found
Spatio-temporal influence of tundra snow properties on Ku-band (17.2 GHz) backscatter
No full textDuring the 2010/11 boreal winter, a distributed set of backscatter measurements was collected using a ground-based Ku-band (17.2 GHz) scatterometer system at 26 open tundra sites. A standard snow-sampling procedure was completed after each scan to evaluate local variability in snow layering, depth, density and water equivalent (SWE) within the scatterometer field of view. The shallow depths and large basal depth hoar encountered presented an opportunity to evaluate backscatter under a set of previously untested conditions. Strong Ku-band response was found with increasing snow depth and snow water equivalent (SWE). In particular, co-polarized vertical backscatter increased by 0.82 dB for every 1 cm increase in SWE (R2 = 0.62). While the result indicated strong potential for Ku-band retrieval of shallow snow properties, it did not characterize the influence of sub-scan variability. An enhanced snow-sampling procedure was introduced to generate detailed characterizations of stratigraphy within the scatterometer field of view using near-infrared photography along the length of a 5m trench. Changes in snow properties along the trench were used to discuss variations in the collocated backscatter response. A pair of contrasting observation sites was used to highlight uncertainties in backscatter response related to short length scale spatial variability in the observed tundra environment
Michael Rodriguez interviews author Tom Springer
No full textAuthor Tom Springer is interviewed about his writing career and his newest book "Looking for hickories". Springer talks about his career following after earning an Environmental Journalism degree from Michigan State University. He calls his genre "creative non-fiction" and explains how he weaves his memories into his books about life in rural and wild Michigan. Part of the Michigan State University Libraries' Michigan Writers Series. Springer is interviewed by Librarian Michael Rodriguez
Tom Thomson Pulls Children in Snow
No full textTom Thomson pulls his children Sarah,4, and Brian,2, through the snow-filled road of Liberty Street. The Thomsons live at 709 Franklin Street
Tom Sevy Shows Snow Depth on Forest
No full textSignpost at junction of Iron Springs and East Park roads show depth of snow at this point. Tom Sevy, district forest ranger, is adjusting sign
Performing the archive: following in the footsteps
No full textUsing documentation of Mike Pearson's performance 'Bubbling Tom', Deirdre Heddon attempts to step into his shoes and re-perform it
CRE Author Tom Franklin
No full textCommon Reading Experience author and UM creative writing instructor Tom Franklin talks about his novel, Crooked Letter, Crooked Letter. Video by Mary Stanton.https://egrove.olemiss.edu/umvideo/1334/thumbnail.jp
Tom Kubancik
No full textTom is the Vice President of Advanced Programs at Applied Defense Solutions (ADS).
Tom’s entire career has been focused on advanced technology with over 30 years in Space Systems, High Performance Computing, and Microelectronics. With a background in Operations Management, Tom has enjoyed broad success when pioneering companies in rapidly evolving markets and shaping today’s high technology landscape.
Tom is a recognized international expert in Space Situational Awareness (SSA), participating in research, development, and deployment programs since the 1980’s. At Applied Defense Solutions (ADS), Tom has led the transition away from military-only SSA, establishing a broad portfolio of research and development, commercialization, and operational support programs. ADS is a recognized leader in civilian, commercial, and government space exploration, focusing on all phases from mission analysis, operations support, and space protection. Leading the ADS Advanced Programs’ team, Tom coordinates a highly talented group of technical experts working alongside program managers, operational experts, and capture professionals. Their focus is to create and develop opportunities for ADS to apply its innovations and expertise to the most challenging space systems development tasks. His team harnesses a company-wide passion for problem-solving by leveraging a world class research portfolio with exquisite analytical capabilities and deep operational experience. ADS has constructed the most interesting mission portfolio in the industry as Tom and his team love their role in defining the next generation of safe space operations.
Tom is an active participant in NATO Science and Technology panels and activities leading to better understanding of global approaches for effective coalition and collaborative SSA. Tom is a published author on global SSA and is a frequent speaker at domestic and international conferences.
Tom has a wealth of experience with leadership positions. He is a graduate of Bowling Green University. Tom and his family live in Boulder, Colorado.https://commons.erau.edu/stm-images/1097/thumbnail.jp
Strain softening and strain localisation in irreversible deformation of snow
No full textThe aim of this work was to visualise heterogeneous deformation in snow under controlled
laboratory conditions. Heterogeneous deformation was observed for both homogenous and
heterogeneous loading conditions. Understanding deformation of snow is important in many
scientific fields including vehicle traction, avalanche forecasting, and winter sports.
This thesis investigates the deformation behaviour of snow on the centimetre scale under
moderate strain rates (0.005 to 0.1 s-1) when subject to one-dimensional compression or to
indentation. In order to allow controlled and repeatable snow deformation experiments, a
new type of artificial snow was developed. This snow type was examined by low
temperature scanning electron microscopy and by traditional avalanche observer’s
methodology. Penetrometer experiments were conducted on the artificial snow and on
natural seasonal snow in Scotland. The two snow types were found to be similar: results
obtained on artificial snow are thus applicable to natural snow. A reproducible technique of
manufacture and a thorough characterisation of the artificial snow are presented.
One-dimensional compression experiments were conducted on the artificial snow. The
experiments were in confined compression in a specially constructed apparatus, designed to
provide for back-lit photography. Images were taken at 0.25 second intervals and analysed
using digital image correlation, thus providing 2D strain fields. With careful control of
photographic parameters, it is demonstrated that process of applying tracer substances to the
snow is not necessary, thus allowing an unprecedented resolution.
Spontaneously-forming strain localisations were observed for the first time, indicating strain
softening behaviour. Damage was observed to propagate through the specimen as a moving
front, resembling a wave. The force required to propagate the front remained nearly constant
until the whole specimen was compacted, at which point a new front formed and the process
repeated.
The experimental method was extended to 2D indention experiments with a range of sizes
and shapes of indenter. Complex deformation fields were observed, extending up to 6 times
the width of the indenter on each side. Observed deformation included tensile tearing as
well as compression and shear. The maximum local strain achieved in the indentation
experiments was similar to that achieved by the first compaction front in one-dimensional
compression.
The work here presented has implications for snow deformation generally: strain localisation
introduces a characteristic length, which may prevent scaling of models or results. The
indentation results are particularly relevant to snow penetrometry, where indentation
experiments are used to try and extract microstructural information from buried snow layers
for the purpose of avalanche prediction. The common assumption that the penetrometer
interacts only with snow very close to its tip may need to be reconsidered
Tom Lawson
No full textTom Lawson is Professor of History and Pro Vice Chancellor for Arts, Design and Social Sciences at Northumbria University. He is the author and editor of several books including Debates on the Holocaust (2010) and most recently The Last Man: a British Genocide in Tasmania (2014).https://commons.erau.edu/genocide-bios/1044/thumbnail.jp
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