bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of variable aeration of monodisperse mixtures: implications for Pyroclastic Density Currents
Authors: Smith Gregory , Williams Rebecca , Rowley Pete , Parsons Daniel
Published: July 2018

The high mobility of dense pyroclastic density currents (PDCs) is commonly attributed to high gas pore pressures. However, the influence of spatial and temporal variations in pore pressure within PDCs has yet to be investigated. Theory suggests that variability in the fluidisation and aeration of a current will have a significant control on PDC flow and deposition. In this study, the effect of spatially heterogeneous gas pore pressures in experimental PDCs was investigated. Sustained, unsteady granular currents were released into a flume channel where the injection of gas through the channel base was controlled to create spatial variations in aeration. Maximum current front velocity results from high degrees of aeration proximal to the source, rather than lower sustained aeration along the whole flume channel. However, moderate aeration (i.e. ~0.5 minimum static fluidisation velocity (Umf_st)) sustained throughout the propagation length of a current results in greater runout distances than currents which are closer to fluidisation (i.e. 0.9 Umf_st) near to source, then de-aerating distally. Additionally, although all aerated currents are sensitive to channel base slope angle, the runout distance of those currents where aeration is sustained throughout their lengths increase by up to 54% with an increase of slope from 2° to 4°. Deposit morphologies are primarily controlled by the spatial differences in aeration; where there is large decrease in aeration the current forms a thick depositional wedge. Sustained gas-aerated granular currents are observed to be spontaneously unsteady, with internal sediment waves travelling at different velocities.
Constraining the sedimentology and stratigraphy of submarine intraslope lobe deposits using exhumed examples from the Karoo Basin, South Africa
Authors: Spychala Yvonne , Hodgson David , Flint Stephen , Mountney Nigel
Published: July 2018

Intraslope lobe deposits provide a record of the infill of accommodation on submarine slopes and their recognition enables the accurate reconstruction of the stratigraphic evolution of submarine slope systems. Extensive exposures of discrete sand-prone packages in Units D/E and E, Fort Brown Formation, Karoo Basin, South Africa, permit analysis of the sedimentology and stacking patterns of three intraslope lobe complexes and their palaeogeographic reconstruction via bed-scale analysis and physical correlation of key stratal surfaces. The sand-prone packages comprise tabular, aggradationally to slightly compensationally stacked lobe deposits with constituent facies associations that can be attributed to lobe axis, lobe off-axis, lobe-fringe and distal lobe-fringe environments. Locally, intraslope lobe deposits are incised by low aspect ratio channels that mark basinward progradation of the deepwater system. The origin of accommodation on the slope for lobe deposition is interpreted to be due to differential compaction or healing of scars from mass wasting processes. The stacking patterns and sedimentary facies arrangement identified in this study are distinct from those of more commonly recognised basin-floor lobe deposits, thereby enabling the establishment of recognition criteria for intraslope lobe deposits in other less well exposed and studied fine-grained systems. Compared to basin floor lobes, intraslope lobes are smaller volume, influenced by higher degrees of confinement, and tend to show aggradational stacking patterns.
Optimising tidal range power plant operation
Authors: Angeloudis Athanasios , Kramer Stephan , Avdis Alexandros , Piggott Matthew
Published: July 2018

Tidal range power plants represent an attractive approach for the large-scale generation of electricity from the marine environment. Even though the tides and by extension the available energy resource are predictable, they are also variable in time. This variability poses a challenge regarding the optimal transient control of power plants. Here we consider simulation methods which include the main modes of operation of tidal power plants, along with algorithms to regulate the timing of these.This paper proposes a framework where simplified power plant operation models are coupled with gradient-based optimisation techniques to determine the optimal control strategy over multiple tidal cycles. The optimisation results in turn inform coastal ocean simulations that include tidal power plants to gauge whether the benefits of an adaptive operation are preserved once their hydrodynamic impacts are also taken into consideration. The combined operation of two prospective tidal lagoon projects within the Bristol Channel and the Severn Estuary is used as an example to demonstrate the potential benefits of an energy maximisation optimisation approach.For the case studies considered, the inclusion of pumping and an adaptive operation is shown to deliver an overall increase in energy output of 20-40 % compared to a conventional two-way uniform operation. The findings also demonstrate that smaller schemes stand to gain more from operational optimisation compared to designs of a larger scale.
A strong role for the AMOC in partitioning global energy transport and shifting ITCZ position in response to latitudinally discrete solar forcing in the CESM1.2
Authors: Yu Sungduk , Pritchard Mike
Published: July 2018

This preprint is a non peer reviewed version submitted to the Journal of Climate. This work has been accepted for publication with an updated title, A strong role for the AMOC in partitioning global energy transport and shifting ITCZ position in response to latitudinally discrete solar forcing in the CESM1.2. The accepted version is substantially different from the preprint version due to the changes and new analysis made during a peer review process. Readers are encouraged to refer to the final version, which is available at https://doi.org/10.1175/JCLI-D-18-0360.1.
Understanding snow hydrological processes through the lens of stable water isotopes
Authors: Beria Harsh , Larsen Joshua , Ceperley Natalie , Michelon Anthony , Vennemann Torsten , Schaefli Bettina
Published: July 2018

Snowfall may have different stable isotopic compositions compared to rainfall, allowing its contribution to potentially be tracked through the hydrological cycle. This review summarizes the state of knowledge of how different hydro-meteorological processes affect the isotopic composition of snow, and, through selected examples, discusses how stable water isotopes can provide a better understanding of snow hydrological processes. A detailed account is given of how the variability in isotopic composition of snow changes from precipitation to final melting. The effect of different snow ablation processes (sublimation, melting, and redistribution by wind or avalanches) on the isotope ratios of the underlying snowpack are also examined. Insights into the role of canopy in snow interception processes, and how the isotopic composition in canopy underlying snowpacks can elucidate the exchanges therein are discussed, as well as case studies demonstrating the usefulness of stable water isotopes to estimate seasonality in the groundwater recharge. Rain-on-snow floods illustrate how isotopes can be useful to estimate the role of preferential flow during heavy spring rains. All these examples point to the complexity of snow hydrologic processes and demonstrate that an isotopic approach is useful to quantify snow contributions throughout the water cycle, especially in high elevation and high latitude catchments, where such processes are most pronounced. This synthesis concludes by tracing a snow particle along its entire hydrologic life cycle, highlights the major practical challenges remaining in snow hydrology and discusses future research directions.
Location and probability of shoal margin collapses in a sandy estuary
Authors: van Dijk Wout , Mastbergen Dick , Ham Geeralt , Leuven Jasper , Kleinhans Maarten
Published: July 2018

Channel bank failure, collapses of shoal margins and beaches due to flow slides have been recorded in Dutch estuaries for the past 200 years but have hardly been recognized elsewhere. Current predictions lack forecasting capabilities, because they were validated and calibrated for historic data of cross-sections in specific systems, allowing local hindcast rather than location and probability forecasting. The objectives of this study are to investigate where on shoal margins collapses typically occur and what shoal margin collapse geometries and volumes are, such that we can predict their occurrence. We identified shoal margin collapses, generally completely submerged, from bathymetry data by analyzing DEMs of Difference (DoD) of the Western Scheldt for the period 1959-2015. We used the bathymetry data to determine the conditions for occurrence, specifically to obtain slope height and angle and applied these variables in a shoal margin collapse predictor. We found 299 collapses along 300 km of shoal margin boundaries over 56 years, meaning more than 5 collapses occur on average per year. The average shoal margin collapse body is well approximated by a 1/3 ellipsoid shape, covers on average an area of 34,000 m2, and has an average volume of 100,000 m3. Shoal margin collapses occur mainly at locations where shoals take up a proportionally larger area than average in the cross-section of the entire estuary, and occur most frequently where lateral shoal margin displacement is low. A receiver operating characteristic curve shows that the forecasting method predicts the shoal margin collapse location well. We conclude that the locations of the shoal margin collapses are well predicted by the variation in conditions of the relative slope height and angle within the Western Scheldt, and likely locations are at laterally relatively stable shoal margins. This provides hypotheses aiding the recognition of these features in sandy estuaries worldwide.
Rifts and Rifted Margins: A Review of Geodynamic Processes and Natural Hazards
Authors: Brune Sascha
Published: July 2018

This review provides an introduction to the geodynamic processes that influence tectonic rift evolution and rifted margin architecture. With a strong focus on numerical modeling, I summarize classical and recent insights on rift evolution with differentiation between 2D and 3D concepts and models. One of the key processes during rift evolution is crust-mantle coupling, which controls not only the width of a rift system but also crustal hyper-extension and the degree of final margin asymmetry. Accounting for 3D rift geometries allows investigating along-strike heterogeneities, rift segmentation and rift obliquity. Large amounts of sediments have accumulated at rifted margins, especially at the mouths of large rivers and former glaciers, providing important stratigraphic archives and georesources. Shifting the focus from the geological scale of continental extension to the human time scale, natural hazards are discussed regarding earthquakes and volcanic eruptions during active rifting. Finally, I review natural hazards due to passive margin seismicity as well as slope instabilities at heavily sedimented continental margins that have the potential to generate large landslide tsunamis.
Fault growth and interactions in a multiphase rift fault network: Horda Platform, Norwegian North Sea
Authors: Duffy Oliver , Bell Rebecca , Jackson Christopher , Gawthorpe Robert , Whipp Paul
Published: July 2018

Physical models predict that multiphase rifts that experience a change in extension direction between stretching phases will typically develop non-colinear normal fault sets. Furthermore, multiphase rifts will display a greater frequency and range of styles of fault interactions than single-phase rifts. Although these physical models have yielded useful information on the evolution of fault networks in map view, the true 3D geometry of the faults and associated interactions are poorly understood. Here, we use an integrated 3D seismic reflection and borehole dataset to examine a range of fault interactions that occur in a natural multiphase fault network in the northern Horda Platform, northern North Sea. In particular we aim to: i) determine the range of styles of fault interaction that occur between non-colinear faults; ii) examine the typical geometries and throw patterns associated with each of these different styles; and iii) highlight the differences between single-phase and multiphase rift fault networks. Our study focuses on a ca. 350 km2 region around the >60 km long, N–S-striking Tusse Fault, a normal fault system that was active in the Permian–Triassic and again in the Late Jurassic-to-Early Cretaceous. The Tusse Fault is one of a series of large (>1500 m throw) N–S-striking faults forming part of the northern Horda Platform fault network, which includes numerous smaller (2–10 km long), lower throw (<100 m), predominantly NW–SE-striking faults that were only active during the Late Jurassic to Early Cretaceous. We examine how the 2nd-stage NW–SE-striking faults grew, interacted and linked with the N–S-striking Tusse Fault, documenting a range of interaction styles including mechanical and kinematic isolation, abutment, retardation and reactivated relays. Our results demonstrate that: i) isolated, and abutting interactions are the most common fault interaction styles in the northern Horda Platform; ii) pre-existing faults can act as sites of nucleation for 2nd-stage faults or may form mechanical barriers to propagation; iii) the throw distribution on reactivated 1st-stage faults will be modified in a predictable manner if they are intersected or influenced by 2nd-stage faults; iv) sites of fault linkage and relay-breaching associated with the first phase of extension can act as preferential nucleation sites for 2nd-stage faults; and v) the development of fault intersections is a dynamic process, involving the gradual transition from one style to another.
Structure and anisotropy of the Mexico subduction zone based on Rayleigh-wave analysis and implications for the geometry of the Trans-Mexican Volcanic Belt
Authors: Stubailo Igor , Beghein Caroline , Davis Paul
Published: July 2018

We develop a three-dimensional model of shear wave velocity and anisotropy for the Mexico subduction zone using Rayleigh wave phase velocity dispersion measurements. This region is characterized by both steep and flat subduction and a volcanic arc that appears to be oblique to the trench. We give a new interpretation of the volcanic arc obliqueness and the location of the Tzitzio gap in volcanism based on the subduction morphology. We employ the two-station method to measure Rayleigh phase velocity dispersion curves between periods of 16 s to 171 s. The results are then inverted to obtain azimuthally anisotropic phase velocity maps and to model 3-D variations in upper mantle velocity and anisotropy. Our maps reveal lateral variations in phase velocity at all periods, consistent with the presence of flat and steep subduction. We also find that the data are consistent with two layers of anisotropy beneath Mexico: a crustal layer, with the fast directions parallel to the North American absolute plate motion, and a deeper layer that includes the mantle lithosphere and the asthenosphere, with the fast direction interpreted in terms of toroidal mantle flow around the slab edges. Our combined azimuthal anisotropy and velocity model enables us to analyze the transition from flat to steep subduction and to determine whether the transition involves a tear resulting in a gap between segments or is a continuous deformation caused by a lithospheric flexure. Our anisotropy results favor a tear, which is also consistent with the geometry of the volcanic belt.
Increased ice loading in the Antarctic Peninsula since the 1850s and its effect on Glacial Isostatic Adjustment
Authors: Nield Grace , Whitehouse Pippa , King Matt , Clarke Peter , Bentley Michael
Published: July 2018

Antarctic Peninsula (AP) ice core records indicate significant accumulation increase since 1855, and any resultant ice mass increase has the potential to contribute substantially to present-day Glacial Isostatic Adjustment (GIA). We derive empirical orthogonal functions from climate model output to infer typical spatial patterns of accumulation over the AP and, by combining with ice core records, estimate annual accumulation for the period 1855-2010. In response to this accumulation history, high resolution ice-sheet modeling predicts ice thickness increases of up to 45 m, with the greatest thickening in the northern and western AP. Whilst this thickening is predicted to affect GRACE estimates by no more than 6.2 Gt/yr, it may contribute up to -7 mm/yr to the present-day GIA uplift rate, depending on the chosen Earth model, with a strong east-west gradient across the AP. Its consideration is therefore critical to the interpretation of observed GPS velocities in the AP.
Spatial association between regionalizations using the information-theoretical V-measure
Authors: Nowosad Jakub , Stepinski Tomasz
Published: July 2018

There is a keen interest in inferring spatial associations between different variables spanning the same study area. We present a method for quantitative assessment of such associations in the case where spatial variables are either in the form of regionalizations or in the form of thematic maps. The proposed index of spatial association – called the V-measure – is adapted from a measure originally developed in computer science, where it was used to compare clusterings, to spatial science for comparing regionalizations. The V-measure is rooted in the information theory and, at its core, it is equivalent to mutual information between the two regionalizations. Here we re-introduce the V-measure in terms of spatial variance analysis instead of information theory. We identify three different contexts for application of the V-measure, comparative, associative, and derivative, and present an example of an application for each of them. In the derivative context, the V-measure is used to select an optimal number of regions for clustering-derived regionalizations. In effect, this also constitutes a novel way to determine the number of clusters for non-spatial clustering tasks as well. The advantage of V-measure over the Mapcurves method is discussed. We also use the insight from deriving the V-measure in terms of spatial variance analysis to point out a shortcoming of the Geographical Detector – a method to quantify associations between numerical and categorical spatial variables. The open-source software for calculating the V-measure accompanies this paper.
Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation
Authors: Lipovsky Bradley , Dunham Eric
Published: July 2018

Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid‐filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis, valid at wavelengths greater than the fracture aperture, that accounts for quasi‐static elastic deformation of the fracture walls, as well as fluid viscosity, inertia, and compressibility. In the long‐wavelength limit, anomalously dispersed guided waves known as crack or Krauklis waves propagate with restoring force from fracture wall elasticity. At shorter wavelengths, the waves become sound waves within the fluid channel. Wave attenuation in our model is due to fluid viscosity, rather than seismic radiation from crack tips or fracture wall roughness. We characterize viscous damping at both low frequencies, where the flow is always fully developed, and at high frequencies, where the flow has a nearly constant velocity profile away from viscous boundary layers near the fracture walls. Most observable seismic signals from resonating fractures likely arise in the boundary layer crack wave limit, where fluid‐solid coupling is pronounced and attenuation is minimal. We present a method to estimate the aperture and length of a resonating hydraulic fracture using both the seismically observed quality factor and characteristic frequency. Finally, we develop scaling relations between seismic moment and characteristic frequency that might be useful when interpreting the statistics of hydraulic fracture events.
Thermo-mechanical numerical model of the transition from continental rifting to oceanic spreading: the case study of the Alpine Tethys
Authors: Roda Manuel , Marotta Anna , Conte Katya , Spalla Maria
Published: July 2018

We develop a two-dimensional thermo-mechanical numerical model in which the formation of oceanic crust and serpentinite due to the hydration of the uprising mantle peridotite has been implemented, with the aim of discussing the behavior of the lithosphere of the Alps and Northern Apennines during the transition from continental rifting to ocean spreading of the Alpine Tethys. The predictions of the model are compared with natural data related to the Permian–Triassic high- temperature – low-pressure (HT-LP) metamorphism affecting the continental lithosphere and data from the Jurassic P–T evolution of the oceanic lithosphere from the Alps and the Northern Apennines. Our analysis indicates that a thinned continental crust, an ocean–continent transition zone and an oceanic lithosphere characterize the final structure of the system in a poor magma rift pre-Alpine configuration. We also find that mantle serpentinization starts before crustal break-up and that denudation occurs before ocean spreading. The mantle denudation starts several million years before the gabbros/basalt formation, generating an ocean–continent transition zone from the passive continental margin to the oceanic lithosphere of size 160–280 km. The comparative analysis shows that the extension of a hot and weak lithosphere, which promotes the development of hyperextended Alpine margins, better agrees with the natural data. Finally, our comparative analysis supports the hypothesis that the lithospheric extension preceding the opening of the Alpine Tethys did not start in a stable continental lithosphere, but developed by recycling part of the old Variscan collisional suture.
On the scales of dynamic topography in whole-mantle convection models - preprint version
Authors: ARNOULD Maëlis , Coltice Nicolas , Flament Nicolas , Seigneur Valentin , Müller Dietmar
Published: July 2018

Mantle convection shapes Earths surface by generating dynamic topography. Observational constraints and regional convection models suggest that surface topography could be sensitive to mantle flow for wavelengths as short as 1,000 km and 250 km, respectively. At these spatial scales, surface processes including sedimentation and relative sea-level change occur on million year timescales. However, time dependent global mantle flow models do not predict small-scale dynamic topography yet. Here, we present 2D-spherical annulus numerical models of mantle convection with large radial and lateral viscosity contrasts. We first identify the range of Rayleigh number, internal heat production rate and yield stress for which models generate plate-like behaviour, surface heat flow, surface velocities and topography distribution comparable to Earths. These models produce both whole mantle convection and small-scale convection in the upper mantle, which results in small- (< 500 km) to large-scale (> 10^4 km) dynamic topography, with a spectral power for intermediate scales (500 to 10^4 km) comparableto estimates of present-day residual topography. Timescales of convection and the associated dynamic topography vary from five to several hundreds of millions of years. For a Rayleigh number of 10^7, we investigate how lithosphereyield stress variations (10-50 MPa) and the presence of deep thermochemical heterogeneities favour small-scale (200-500 km) and intermediate scale (500-10^4 km) dynamic topography by controlling the formation of small scale convection and the number and distribution of subduction zones, respectively. The interplay between mantle convection and lithosphere dynamics generates a complex spatial and temporal pattern of dynamic topography consistent with constraints for Earth.
Seismic Monitoring of the North Korea Nuclear Test Site Using a Multichannel Correlation Detector
Authors: Gibbons Steven , Ringdal Frode
Published: July 2018

North Korea announced a second nuclear test on 25 May 2009, the first having taken place on October 9, 2006. Both tests were detected by the global seismic network of the Comprehensive nuclear Test-Ban-Treaty Organisation. We apply a correlation detector using a 10-s signal template from the 2006 test on the MJAR array in Japan to: 1) assess the potential for automatically detecting subsequent explosions at or near the test site; and 2) monitor the associated false alarm rate. The 2009 signal is detected clearly with no false alarms in a three-year period. By detecting scaled-down copies of the explosion signals submerged into background noise, we argue that a significantly smaller explosion at the site would have been detected automatically, with a low false alarm rate. The performance of the correlator on MJAR is not diminished by the signal incoherence that makes conventional array processing problematic at this array. We demonstrate that false alarm elimination by f-k analysis of single channel detection statistic traces is crucial for maintaining a low detection threshold. Correlation detectors are to be advocated as a routine complement to the existing pipeline detectors, both for reducing the detection threshold for sites of interest and providing automatic classification of signals from repeating sources.
Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta
Authors: Clare Michael , Talling Peter , Cartigny Matthieu , Pratomo Danar , Clarke John
Published: July 2018

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting.
The signal of mantle anisotropy in the coupling of normal modes
Authors: Beghein Caroline , Resovsky Joseph , van der Hilst Robert
Published: July 2018

We investigate whether the coupling of normal mode (NM) multiplets can help us constrain mantle anisotropy.We first derive explicit expressions of the generalized structure coefficients of coupled modes in terms of elastic coefficients, including the Love parameters describing radial anisotropy and the parameters describing azimuthal anisotropy (Jc, Js, Kc, Ks, Mc, Ms, Bc, Bs, Gc, Gs, Ec, Es, Hc, Hs, Dc and Ds ). We detail the selection rules that describe which modes can couple together and which elastic parameters govern their coupling. We then focus on modes of type 0Sl − 0T l+1 and determine whether they can be used to constrain mantle anisotropy. We show that they are sensitive to six elastic parameters describing azimuthal anisotropy, in addition to the two shear-wave elastic parameters L and N (i.e. VSV and VSH ).We find that neither isotropic nor radially anisotropic mantle models can fully explain the observed degree two signal. We show that the NM signal that remains after correction for the effect of the crust and mantle radial anisotropy can be explained by the presence of azimuthal anisotropy in the upper mantle. Although the data favour locating azimuthal anisotropy below 400 km, its depth extent and distribution is still not well constrained by the data. Consideration of NM coupling can thus help constrain azimuthal anisotropy in the mantle, but joint analyses with surface-wave phase velocities is needed to reduce the parameter trade-offs and improve our constraints on the individual elastic parameters and the depth location of the azimuthal anisotropy
Characterising Drainage Multiphase Flow in Heterogeneous Sandstones
Authors: Jackson Samuel , Agada Simeon , Reynolds Catriona , Krevor Sam
Published: July 2018

In this work, we analyse the characterisation of drainage multiphase flow properties on heterogeneous rock cores using a rich experimental dataset and mm-m scale numerical simulations. Along with routine multiphase flow properties, 3D sub-metre scale capillary pressure heterogeneity is characterised by combining experimental observations and numerical calibration, resulting in a 3D numerical model of the rock core. The uniqueness and predictive capability of the numerical models are demonstrated by accurately predicting the experimentally measured relative permeability of N2-DI water and CO2-brine systems in two distinct sandstone rock cores across multiple fractional flow regimes and total flow rates. The numerical models are used to derive equivalent relative permeabilities, which are upscaled functions incorporating the effects of sub-metre scale capillary pressure. The functions are obtained across capillary numbers which span four orders of magnitude, representative of the range of flow regimes that occur in subsurface CO2 injection. Removal of experimental boundary artefacts allows the derivation of equivalent functions which are characteristic of the continuous subsurface. We also demonstrate how heterogeneities can be re-orientated and re-structured efficiently to obtain large amounts of information about expected flow regimes through different small-scale rock structures. This analysis shows how combined experimental and numerical characterisation of rock samples can be used to derive equivalent flow properties from heterogeneous rocks.
Volcanic ash generation mechanisms: Fingerprints in phase distribution highlighted by QEMSCAN particle mineralogical analysis
Authors: Hornby Adrian , Lavallée Yan , Kendrick Jackie , Rollinson Gavyn , Butcher Alan , Clesham Steve , Kueppers Ulrich , Cimarelli Corrado , Chigna Gustavo
Published: July 2018

Volcanic ash particle properties depend upon their genetic fragmentation processes. Here, we introduce QEMSCAN particle mineralogical analysis (PMA) to quantify the phase distribution in two ash samples collected during activity at Santiaguito, Guatemala and assess the fingerprint of fragmentation mechanisms. Volcanic ash from a Vulcanian explosion and from a pyroclastic density current resulting from a dome collapse event were selected. The ash particles resulting from both fragmentation modes are dense and blocky, typical of open-vent dome volcanoes and have a componentry consistent with their andesitic composition. We use image analysis to compare the fraction of plagioclase and glass at particle boundaries compared to the total particle fraction. Our results show that the explosion-derived ash has an even distribution of plagioclase and glass, but boundaries enriched in pyroxene and amphibole. In contrast, the ash generated during dome collapse has an increased fraction of glass and decreased fraction of plagioclase at particle boundaries, suggesting that fractures preferentially propagate through glass during abrasion and milling in pyroclastic flows. This study presents analysis of QEMSCAN PMA data as a new technique to identify generation mechanisms of volcanic ash, which is pertinent to volcanology, aviation, respiratory health and environmental hazards, and highlights the need for further experimental constraints on the fragmentation mechanism fingerprint.
Computationally Efficient Tsunami Modelling on Graphics Processing Units (GPU)
Authors: Amouzgar Reza , Liang Qiuhua , Clarke Peter , Yasuda Tomohiro , Mase Hajime
Published: July 2018

Tsunamis generated by earthquakes commonly propagate as long waves in the deep ocean and develop into sharp-fronted surges moving rapidly towards the coast in shallow water, which may be effectively simulated by hydrodynamic models solving the nonlinear shallow water equations (SWEs). However, most of the existing tsunami models suffer from long simulation time for large-scale real-world applications. In this work, a graphics processing unit (GPU) accelerated finite volume shock-capturing hydrodynamic model is presented for computationally efficient tsunami simulations. The improved performance of the GPU-accelerated tsunami model is demonstrated through a laboratory benchmark test and a field-scale simulation.
INFORMATION SYSTEM SALES OF INDOOR AND OUTDOOR ORNAMENTAL PLANTS-BASED ONLINE
Authors: Sutedi Sutedi
Published: July 2018

Ornamental plants have fairly high commercial value and much sought after by various circles. The prospect is in the business of ornamental plants can be said very brilliant and profitable. Where is in the business of ornamental plants can bring about advantages not the least. The business struggled with ornamental plants can have very favorable prospects for the long term. There are an awful lot of various kinds of ornamental plants that we can choose to use as ornaments to beautify residential home. The ornamental plants can be used as indoor ornamental plants placed in homes or can also be used as outdoor ornamental plants grown in the garden. Ornamental plants while more popular community-wide information system for ornamental plant however is currently designed specifically and not many people who know the information on price and specs or type of indoor and outdoor ornamental plants so that the need for sales information system of indoor and outdoor ornamental plants-based online. With the sales information system of Indoor and Outdoor ornamental plants-based online is expected to facilitate the customers, business processes that occur in the company's units, unit – units that exist within the system a functioning production units as the unit working on/produce ornamental plants. With the utilization of the system marketing media, promoting, finding new customers, the sales process, recapitulation payment of ornamental plants, control the conditions of stock products, development and delivery of products to customers including convincing the product gets to the customer
Ampli: A Construction Set for Paperfluidic Systems
Authors: Phillips Elizabeth A. , Young Anna K. , Albarran Nikolas , Butler Jonah , Lujan Kaira , Hamad-Schifferli Kimberly , Gomez-Marquez Jose
Published: July 2018

The design and fabrication of reconfigurable, modular paperfluidics driven by a prefabricated reusable block library, asynchronous modular paperfluidic linear instrument-free (Ampli) block, are reported. The blocks are inspired by the plug-and-play modularity of electronic breadboards that lower prototyping barriers in circuit design. The resulting biochemical breadboard is a paperfluidic construction set that can be functionalized with chemical, biological, and electrical elements. Ampli blocks can form standard paperfluidic devices without any external instrumentation. Furthermore, their modular nature enhances fluidics in ways that fixed devices cannot. The blocks' ability to start, stop, modify, and reverse reaction flows, reagents, and rates in real time is demonstrated. These enhancements allow users to increase colorimetric signals, fine tune reaction times, and counter check multiplexed diagnostics for false positives or negatives. The modular construction demonstrates that field-ready, distributed fabrication of paper analytical systems can be standardized without requiring the “black box” of craft and technique inherent in paper-based systems. Ampli assembly and point-of-care redesign extends the usability of paper analytical systems and invites user-driven prototyping beyond the lab setting demonstrating “Design for Hack” in diagnostics.
ET-332 Mechanical Project
Authors: Kmieciak David
Published: July 2018

This document was created to design a mechanical advantage for a pre-existing hydroelectric generator setup.
Arduino Hulk
Authors: Miner Benjamin , Zaman Hamza , Watter Matthew , Yang Alee
Published: July 2018

We were tasked with providing an assistive technology of some kind using Arduino technology. We settled on using a hulk action figure and connecting to an array of switches. These switches would then, once set in a certain order, make the action figure do the "hulk smash".
Intrusion Detection System for Applications using Linux Containers
Authors: Abed Amr
Published: July 2018

Linux containers are gaining increasing traction in both individual and industrial use, and as these containers get integrated into mission-critical systems, real-time detection of malicious cyber attacks becomes a critical operational requirement. This paper introduces a real-time host-based intrusion detection system that can be used to passively detect malfeasance against applications within Linux containers running in a standalone or in a cloud multi-tenancy environment. The demonstrated intrusion detection system uses bags of system calls monitored from the host kernel for learning the behavior of an application running within a Linux container and determining anomalous container behavior. Performance of the approach using a database application was measured and results are discussed.
Analysis of Telecom Service Operation Behavior with Time Series
Authors: Civantos Iciar , García-Algarra Javier
Published: July 2018

Operation of complex telecom services is a field that mixes technology, processes and teams. Despite the existence of detailed protocols and automation, the real behavior is hard to measure and predict. The human factor is a source of uncertainty, and this fact is of special relevance when facing stressful situations. Informal team working culture, time shifts or external pressure are main sources of change. In this research we use time series analysis as a statistical proxy to detect this kind of drift in teams that solve network failures if three live services: IPTV, Cloud Infrastructure and IoT. This task isknown as incident management. This would provide not only a numerical evidence of the uncertainty in troubleshooting of digital services but also anassessment about the economic and operational impact of service releases.Changes in best fitting models may reflect different informal work cultures among the operation teams.
Low-Profile Self-Sealing Sample Transfer Flexure Box
Authors: Simon Kevin , Porz Lukas , Swamy Tushar , Chiang Yet-Ming , Slocum Alexander
Published: July 2018

A flexural bearing mechanism has enabled the development of a self-sealing box for protecting air sensitive samples during transfer between glove boxes, micro-machining equipment, and microscopy equipment. The simplicity and self-actuating feature of this design makes it applicable to many devices that operate under vacuum conditions. The models used to design the flexural mechanism are presented in detail. The device has been tested in a Zeiss Merlin GEMINI II scanning electron microscope with Li3PS4 particles, showing effective isolation from air and corrosion prevention.
Methods of Stabilization of Gas Condensates
Authors: Makinde Ibukun
Published: July 2018

Gas condensates are liquid mixtures of high-boiling hydrocarbons of various structures, separated from natural gases during their production at gas condensate fields. When transporting gas through pipelines, the following gas quality conditions should be met:i.During transportation, gases should not cause corrosion of pipelines, fittings, instruments, etc.ii.The quality of the gas must ensure its transportation in a single-phase state i.e., liquid hydrocarbons, gas condensates and hydrates should not form in the pipelines.In order for gas condensates to meet the above-mentioned quality conditions during storage or transportation, they must be stabilized. Gas condensate stabilization is the process of “boiling off” light hydrocarbons from the condensate that would otherwise increase the vapor pressure when conditions are fluctuating.
METODOLOGIA PARA ESTIMAR EL POTENCIAL ENERGETICO EN LAS ESTACIONES AERONAUTICAS DE LA AERONAUTICA CIVIL DE COLOMBIA
Authors: Caballero Diego Armando Reyes , GOMEZ LEONARDO , Charry Ana , Álavarez Laura
Published: July 2018

The following document contains the methodology for estimating the solar energy potential in each of the location zones of the aeronautical stations in Colombia; for Communications, Navigation and Surveillance services. It includes information on the infrastructure of the country's aeronautical stations and their different sources of support. Resumen El siguiente documento contiene la metodológia para la estimación del potencial energético solar en cada una de las zonas de ubicación de las estaciones aeronáuticas en Colombia; para los servicios de Comunicaciones, Navegación y Vigilancia. Contempla información de la infraestructura de las estaciones aeronáuticas del país y sus diferentes fuentes de respaldo.
Design and Implementation of a GPS based Personal Tracking System
Authors: Janwadkar Sudhanshu
Published: July 2018

Tracking based applications have been quite popular in recent times. Most of them have been limited to commercial applications such as vehicular tracking (e.g tracking of a train etc). However, not much work has been done towards design of a personal tracking system. Our Research work is an attempt to design such personal tracking system. In this paper, we have shared glimpses ofour research work.The objective of our research project is to design & develop a system which is capable of tracking and monitoring a person, object or any other asset of importance (called as target). The system uses GPS to determine the exact position of the target. The target is aided with a compact handheld device which consists of a GPS receiver and GSM modem. GPS receiver obtains location coordinates (viz. Latitude & Longitude) from GPS satellites. The location information in NMEA format is decoded, formatted and sent to control station, through a GSM modem. Due to use of Open CPU development platform, no external Microcontroller is required, with additional advantage of compact size product, reduced design & development time and reduced cost.Thus, the proposed system is able to track the accuratelocation of target. This system finds applications in tracking old-age people, tracking animals in forest, tracking delivery of goods etc. Our final designed system is a small-size compact l.S"X3.7S" Tracker system with position accuracy error <30m (100 feet).
Improving Irrigation in Remote Areas: Multi-objective Optimization of a Treadle Pump
Authors: McComb Christopher , Santaeufemia Pablo S , Johnson Nathan G , Shimada Kenji
Published: July 2018

Water-lifting technologies in rural areas of the developing world have enormous potential to stimulate agricultural and economic growth. The treadle pump, a human-powered low-cost pump designed for irrigation in developing countries, can help farmers maximize financial return on small plots of land by ending their dependency on rain-fed irrigation systems. The treadle pump uses a suction piston to draw groundwater to the surface by way of a foot-powered treadle attached to each suction piston. Current treadle pump designs lift water from depths up to 7 meters at a flow-rate of 1–5 liters per second. This work seeks to optimize the design of the Dekhi style treadle pump, which has gained significant popularity due to its simplicity. A mathematical model of the working fluid and treadle pump structure has been developed in this study. Deterministic optimization methods are then employed to maximize the flow rate of the groundwater pumped, maximize the lift height, and minimize the volume of material used for manufacturing. Design variables for the optimization included the dimensions of the pump, well depth, and speed of various parts of the system. The solutions are subject to constraints on the geometry of the system, the bending stress in the treadles, and ergonomic factors. Findings indicate that significant technical improvements can be made on the standard Dekhi design, such as increasing the size of the pump cylinders and hose, while maintaining a standard total treadle length. These improvements could allow the Dekhi pump to be implemented in new regions and benefit additional rural farmers in the developing world.
Advances in the treatment of the electromagnetic cascade in the TRIPOLI-4® Monte-Carlo code
Authors: Mancusi Davide
Published: July 2018

TRIPOLI-4® is a Monte-Carlo particle-transport code developed at CEA-Saclay (France) that is employed in the domains of nuclear-reactor physics, criticality-safety, shielding/radiation protection and nuclear instrumentation. The goal of this paper is to report on current developments, validation and verification made in TRIPOLI-4® in the treatment of electron/positron/photon transport. The new capabilities and improvements concern refinements to the electron transport algorithm, the introduction of a charge-deposition score, the new thick-target bremsstrahlung option, the upgrade of the bremsstrahlung model and the improvement of electron angular straggling at low energy. The importance of each of the developments above is illustrated by comparisons with calculations performed with other codes and with experimental data.
The effects of turbulent flow on wind turbine performance evaluation
Authors: Shalem Gilad Eyal
Published: July 2018

Most of the world's wind turbines operate under various turbulent wind conditions. Turbulent wind is a big source of uncertainty, and could cause, if unaddressed, significant variation from a turbine's calculated efficiency and even its destruction.Turbulent flow in wind turbines has a profound effect on various aspects including structural load, estimation of a site's energy potential, calculated efficiency, and many more. However, even though significant advances have been made in the field of anemometry the subjects of estimating a wind turbine's site energy potential and analyzing a turbine's efficiency has not been updated.In this work high frequency wind measurements that included wind speed using two different anemometers, wind direction and others were gathered and analyzed. The energy potential and efficiency of the turbine was calculated using this data and compared to the figures that would have been received by using the methods described in the IEC 61400-12-2 Standard.Results show that by using a higher frequency measuring system both a site's energy potential and turbine's efficiency can vary substantially in comparison with the methods described in the International Standard.This research can affect the way a future wind turbine's site energy potential is measured, it can cause existing wind turbine to reevaluate their productivity performance, and on top of all it can cause the examination of the validity of the International Standards regarding wind turbine performance: IEC 61400-12-1 and IEC 61400-12-2.