Energy Balance in Small-Scale Waves — An Experimental Approach Using Optical Slope Measuring Technique and Image Processing

Laboratory experiments are typically performed on particulate media to study stress-deformation behavior and to verify or calibrate computer models from controlled or measured boundary stresses and displacements. However, such data do not permit the formation of shear bands, displacement fields within flowing granular media, and other small-scale localized deformation phenomena to be identified. Described are two semiautomated computer vision techniques for accurately determining the two-dimensional displacement field in granular soils from video images obtained through a transparent planar viewing window. The techniques described are applicable for studying the behavior of particulate media under plane strain and certain axisymmetric test conditions. Digital image processing and analysis routines are used in two different computer programs, Tracker and Tracer, Tracker uses a graphical user interface that allows individual particles to be selected and tracked through a sequence of digital video images. A contrast edge detection algorithm delineates the two-dimensional projected boundaries of particles. The location of the centroid of each particle selected for tracking is determined from the boundary to quantify the trajectory of each particle. Tracer maps the trace or trajectory of specially dyed fluorescent particles in a sequence of video frames. A thresholding technique segments individual particle trajectories. Together, Tracker and Tracer provide a set of tools for identifying small-scale displacement fields in particulate assemblies deforming under either quasi-static or rapid loading (such as gravity flow).

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Towards the development of a complex structural inspection system using small-scale aerial vehicles and image processing

2013 IEEE International Systems Conference (SysCon) ◽

10.1109/syscon.2013.6549916 ◽

2013 ◽

Cited By ~ 2

Author(s):

J. Avendano ◽

L. D. Otero ◽

P. Cosentino

Keyword(s):

Image Processing ◽

Small Scale ◽

Inspection System ◽

Aerial Vehicles ◽

Complex Structural ◽

Structural Inspection

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HERschel Observations of Edge-on Spirals (HEROES)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832899 ◽

2018 ◽

Vol 616 ◽

pp. A120 ◽

Cited By ~ 15

Author(s):

Aleksandr V. Mosenkov ◽

Flor Allaert ◽

Maarten Baes ◽

Simone Bianchi ◽

Peter Camps ◽

...

Keyword(s):

Energy Balance ◽

Near Infrared ◽

Complex Geometry ◽

Dust Emission ◽

Three Dimensional ◽

Stellar Model ◽

Small Scale ◽

Balance Study ◽

Balance Problem ◽

Double Exponential

We present results of the detailed dust energy balance study for the seven large edge-on galaxies in the HEROES sample using three-dimensional (3D) radiative transfer (RT) modelling. Based on available optical and near-infrared (NIR) observations of the HEROES galaxies, we derive the 3D distribution of stars and dust in these galaxies. For the sake of uniformity, we apply the same technique to retrieve galaxy properties for the entire sample: we use a stellar model consisting of a Sérsic bulge and three double-exponential discs (a superthin disc for a young stellar population and thin and thick discs for old populations). For the dust component, we adopt a double-exponential disc with the new THEMIS dust-grain model. We fit oligochromatic RT models to the optical and NIR images with the fitting algorithm FITSKIRT and run panchromatic simulations with the SKIRT code at wavelengths ranging from ultraviolet to submillimeter. We confirm the previously stated dust energy balance problem in galaxies: for the HEROES galaxies, the dust emission derived from our RT calculations underestimates the real observations by a factor 1.5–4 for all galaxies except NGC 973 and NGC 5907 (apparently, the latter galaxy has a more complex geometry than we used). The comparison between our RT simulations and the observations at mid-infrared–submillimetre wavelengths shows that most of our galaxies exhibit complex dust morphologies (possible spiral arms, star-forming regions, more extended dust structure in the radial and vertical directions). We suggest that, in agreement with results from the literature, the large- and small-scale structure is the most probable explanation for the dust energy balance problem.

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Resolving Small‐Scale Forest Snow Patterns Using an Energy Balance Snow Model With a One‐Layer Canopy

Water Resources Research ◽

10.1029/2019wr026129 ◽

2020 ◽

Vol 56 (1) ◽

Cited By ~ 4

Author(s):

Giulia Mazzotti ◽

Richard Essery ◽

C. David Moeser ◽

Tobias Jonas

Keyword(s):

Energy Balance ◽

Small Scale ◽

Snow Model

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Hα Emission from the Magellanic Bridge

Publications of the Astronomical Society of Australia ◽

10.1071/as07010 ◽

2007 ◽

Vol 24 (2) ◽

pp. 69-76 ◽

Cited By ~ 9

Author(s):

E. Muller ◽

Q. A. Parker

Keyword(s):

Energy Balance ◽

Molecular Hydrogen ◽

Preliminary Report ◽

Stellar Population ◽

Line Emission ◽

Turbulent Structure ◽

Small Scale ◽

Hα Emission

AbstractWe present here a preliminary report and commentary of recently processed observations of Hα emission towards the Magellanic Bridge. These data have been analysed in an attempt to quantify the extent to which the stellar population is capable of reshaping the local ISM. We find that the Hα emission regions are small, weak and sparsely distributed, consistent with a relatively quiescent and inactive ISM where radiative and collisional ionisation is inefficient and sporadic. This suggests that energetic processes at the small scale (i.e. ∼tens of pc) do not dominate the energy balance within the ISM of the Bridge, which therefore hosts a pristine turbulent structure, otherwise inaccessible within our own Galaxy. We find Hα emission that is well correlated with detected 12CO(1–0) line emission (a proxy for molecular hydrogen), as well as other easily identified ring-like Hı features.

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Low Discounting Behavior among Small-Scale Fishers in Fiji and Sabah, Malaysia

Sustainability ◽

10.3390/su3060897 ◽

2011 ◽

Vol 3 (6) ◽

pp. 897-913 ◽

Cited By ~ 4

Author(s):

Louise S. L. Teh ◽

Lydia C. L. Teh ◽

U. Rashid Sumaila

Keyword(s):

Experimental Approach ◽

Small Scale ◽

Economic Factors ◽

Discount Rates ◽

Cultural Economic ◽

Conservation Policies ◽

Management Interventions ◽

Tropical Reef ◽

Management And Conservation ◽

Socio Economic Factors

Understanding the socio-economic factors that are associated with fishers’ willingness to delay gratification may be useful for designing appropriate fisheries management and conservation policies. We aim to identify the predictors of low discounting behaviour among fishers, which is analogous to having a longer-term outlook. We base our empirical study on two small-scale tropical reef fisheries in Sabah, Malaysia, and Fiji. We use an experimental approach to identify fishers with low discount rates, and then use a logistic regression model to identify predictors of low discount rates. We find that 42% of the respondents have low discount rates, and that site and village level variables are significant predictors of low discount rates. Within Sabah and Fiji, boat ownership and relative catch differentiate low discounting from non-low discounting fishers, but these variables have contradictory effects in Sabah and Fiji. Overall, our results imply that a substantial proportion of reef fishers may be willing to engage in conservation initiatives; however, local socio-cultural, economic, and ecological conditions have to be considered first during the process of designing management interventions.

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Self-similarity in glacier surface characteristics

Journal of Glaciology ◽

10.3189/172756503781830368 ◽

2003 ◽

Vol 49 (167) ◽

pp. 547-554 ◽

Cited By ~ 27

Author(s):

Neil S. Arnold ◽

W. Gareth Rees

Keyword(s):

Surface Roughness ◽

Energy Balance ◽

Spatial Variability ◽

Snow Depth ◽

Surface Albedo ◽

Small Scale ◽

Late Winter ◽

Glacier Surface ◽

Correlation Lengths ◽

Aerodynamic Roughness

AbstractCatchment-wide information on glacier snow-cover depth, surface albedo and surface roughness is important input data for distributed models of glacier energy balance. In this study, we investigate the small-scale (mm to 100 m) spatial variability in these properties, with a view to better simulating this variability in such models. Data were collected on midre Lovénbreen, a 6 km2 valley glacier in northwest Svalbard. The spatial variability of all three properties was found to be self-similar over the range of scales under investigation. Snow depth and albedo exhibit a correlation length within which measurements were spatially autocorrelated. Late-winter and summer properties of snow depth differed, with smaller depths in summer due to melt, and shorter correlation lengths. Similar correlation lengths for snow depth and surface albedo may suggest that snow-depth variation is an important control on the small-scale spatial variability of glacier surface albedo. For surface roughness, the data highlight a possible problem in energy-balance studies which use microtopographic surveys to calculate aerodynamic roughness, in that the scale of the measurements made affects the calculated roughness value. This suggests that further investigations of the relationships between surface form and aerodynamic roughness of glacier surfaces are needed.

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