Submesoscale features and their interaction with fronts and internal tides in a high-resolution coupled atmosphere-ocean-wave model of the Bay of Bengal

Science.gov (United States)

Jensen, Tommy G.; Shulman, Igor; Wijesekera, Hemantha W.; Anderson, Stephanie; Ladner, Sherwin

2018-03-01

Large freshwater fluxes into the Bay of Bengal by rainfall and river discharges result in strong salinity fronts in the bay. In this study, a high-resolution coupled atmosphere-ocean-wave model with comprehensive physics is used to model the weather, ocean circulation, and wave field in the Bay of Bengal. Our objective is to explore the submesoscale activity that occurs in a realistic coupled model that resolves mesoscales and allows part of the submesoscale field. Horizontal resolution in the atmosphere varies from 2 to 6 km and is 13 km for surface waves, while the ocean model is submesoscale permitting with resolutions as high as 1.5 km and a vertical resolution of 0.5 m in the upper 10 m. In this paper, three different cases of oceanic submesoscale features are discussed. In the first case, heavy rainfall and intense downdrafts produced by atmospheric convection are found to force submesoscale currents, temperature, and salinity anomalies in the oceanic mixed layer and impact the mesoscale flow. In a second case, strong solitary-like waves are generated by semidiurnal tides in the Andaman Sea and interact with mesoscale flows and fronts and affect submesoscale features generated along fronts. A third source of submesoscale variability is found further north in the Bay of Bengal where river outflows help maintain strong salinity gradients throughout the year. For that case, a comparison with satellite observations of sea surface height anomalies, sea surface temperature, and chlorophyll shows that the model captures the observed mesoscale eddy features of the flow field, but in addition, submesoscale upwelling and downwelling patterns associated with ageostrophic secondary circulations along density fronts are also captured by the model.

Front-end electronics development for the SSC

International Nuclear Information System (INIS)

Levi, M.

1990-12-01

This is a status report on electronics development undertaken by the Front-End Electronics Collaboration. The overall goal of the collaboration remains the development by 1992 of complete, architecturally compatible, front end electronic systems for calorimeter, wire drift chamber, and silicon strip readout. We report here a few highlights to give a brief overview of the work underway. Performance requirements and capabilities, selected architectures, circuit designs and test results are presented. 13 refs., 21 figs., 1 tab

Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

Science.gov (United States)

Chauché, N.; Hubbard, A.; Gascard, J.-C.; Box, J. E.; Bates, R.; Koppes, M.; Sole, A.; Christoffersen, P.; Patton, H.

2014-08-01

Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. We characterise the main water bodies present and interpret their interaction with their respective calving fronts. We identify two distinct processes of ice-ocean interaction which have distinct spatial and temporal footprints: (1) homogenous free convective melting which occurs across the calving front where AW is in direct contact with the ice mass, and (2) localised upwelling-driven melt by turbulent subglacial runoff mixing with fjord water which occurs at distinct injection points across the calving front. Throughout the study, AW at 2.8 ± 0.2 °C was consistently observed in contact with both glaciers below 450 m depth, yielding homogenous, free convective submarine melting up to ~200 m depth. Above this bottom layer, multiple interactions are identified, primarily controlled by the rate of subglacial fresh-water discharge which results in localised and discrete upwelling plumes. In the record melt year of 2010, the Store Glacier calving face was dominated by these runoff-driven plumes which led to a highly crenulated frontal geometry characterised by large embayments at the subglacial portals separated by headlands which are dominated by calving. Rink Glacier, which is significantly deeper than Store has a larger proportion of its submerged calving face exposed to AW, which results in a uniform, relatively flat overall frontal geometry.

Ship Observations and Numerical Simulation of the Marine Atmosphericboundary Layer over the Spring Oceanic Front in the Northwestern South China Sea

Science.gov (United States)

Wang, D.; Shi, R.; Chen, J.; Guo, X.; Zeng, L.; Li, J.; Xie, Q.; Wang, X.

2017-12-01

The response of the marine atmospheric boundary layer (MABL) structure to an oceanic front is analyzed using Global Positioning System (GPS) sounding data obtained during a survey in the northwestern South China Sea (NSCS) over a period of about one week in April 2013. The Weather Research and Forecasting (WRF) model is used to further examine the thermodynamical mechanisms of the MABL's response to the front. The WRF model successfully simulates the change in the MABL structure across the front, which agrees well with the observations. The spatially high-pass-filtered fields of sea surface temperature (SST) and 10-m neutral equivalent wind from the WRF model simulation show a tight, positive coupling between the SST and surface winds near the front. Meanwhile, the SST front works as a damping zone to reduce the enhancement of wind blowing from the warm to the cold side of the front in the lower boundary layer. Analysis of the momentum budget shows that the most active and significant term affecting horizontal momentum over the frontal zone is the adjustment of the pressure gradient. It is found that the front in the NSCS is wide enough for slowly moving air parcels to be affected by the change in underlying SST. The different thermal structure upwind and downwind of the front causes a baroclinic adjustment of the perturbation pressure from the surface to the mid-layer of the MABL, which dominates the change in the wind profile across the front.

Can we observe the fronts of the Antarctic Circumpolar Current using GRACE OBP?

Science.gov (United States)

Makowski, J.; Chambers, D. P.; Bonin, J. A.

2014-12-01

The Antarctic Circumpolar Current (ACC) and the Southern Ocean remains one of the most undersampled regions of the world's oceans. The ACC is comprised of four major fronts: the Sub-Tropical Front (STF), the Polar Front (PF), the Sub-Antarctic Front (SAF), and the Southern ACC Front (SACCF). These were initially observed individually from repeat hydrographic sections and their approximate locations globally have been quantified using all available temperature data from the World Ocean and Climate Experiment (WOCE). More recent studies based on satellite altimetry have found that the front positions are more dynamic and have shifted south by up to 1° on average since 1993. Using ocean bottom pressure (OBP) data from the current Gravity Recovery and Climate Experiment (GRACE) we have measured integrated transport variability of the ACC south of Australia. However, differentiation of variability of specific fronts has been impossible due to the necessary smoothing required to reduce noise and correlated errors in the measurements. The future GRACE Follow-on (GFO) mission and the post 2020 GRACE-II mission are expected to produce higher resolution gravity fields with a monthly temporal resolution. Here, we study the resolution and error characteristics of GRACE gravity data that would be required to resolve variations in the front locations and transport. To do this, we utilize output from a high-resolution model of the Southern Ocean, hydrology models, and ice sheet surface mass balance models; add various amounts of random and correlated errors that may be expected from GFO and GRACE-II; and quantify requirements needed for future satellite gravity missions to resolve variations along the ACC fronts.

Biogeography of the Oceans: a Review of Development of Knowledge of Currents, Fronts and Regional Boundaries from Sailing Ships in the Sixteenth Century to Satellite Remote Sensing

Science.gov (United States)

Priede, Imants G.

2014-06-01

The development of knowledge of global biogeography of the oceans from sixteenthcentury European voyages of exploration to present-day use of satellite remote sensing is reviewed in three parts; the pre-satellite era (1513-1977), the satellite era leading to a first global synthesis (1978-1998), and more recent studies since 1998. The Gulf Stream was first identified as a strong open-ocean feature in 1513 and by the eighteenth century, regular transatlantic voyages by sailing ships had established the general patterns of winds and circulation, enabling optimisation of passage times. Differences in water temperature, water colour and species of animals were recognised as important cues for navigation. Systematic collection of information from ships' logs enabled Maury (The Physical Geography of the Sea Harper and Bros. New York 1855) to produce a chart of prevailing winds across the entire world's oceans, and by the early twentieth century the global surface ocean circulation that defines the major biogeographic regions was well-known. This information was further supplemented by data from large-scale plankton surveys. The launch of the Coastal Zone Color Scanner, specifically designed to study living marine resources on board the Nimbus 7 polar orbiting satellite in 1978, marked the advent of the satellite era. Over subsequent decades, correlation of satellite-derived sea surface temperature and chlorophyll data with in situ measurements enabled Longhurst (Ecological Geography of the Sea. Academic Press, New York 1998) to divide the global ocean into 51 ecological provinces with Polar, Westerly Wind, Trade Wind and Coastal Biomes clearly recognisable from earlier subdivisions of the oceans. Satellite imagery with semi-synoptic images of large areas of the oceans greatly aided definition of boundaries between provinces. However, ocean boundaries are dynamic, varying from season to season and year to year. More recent work has focused on the study of variability of

Front Probability, NOAA GOES Imager, 0.05 degrees, Western Hemisphere, EXPERIMENTAL

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The data indicates the probability of oceanic sea surface temperature fronts off the California coast. They were created using remote sensing sea surface temperature...

Collaborative project. Ocean-atmosphere interaction from meso-to planetary-scale. Mechanisms, parameterization, and variability

Energy Technology Data Exchange (ETDEWEB)

Small, Richard [National Center for Atmospheric Research, Boulder, CO (United States); Bryan, Frank [National Center for Atmospheric Research, Boulder, CO (United States); Tribbia, Joseph [National Center for Atmospheric Research, Boulder, CO (United States); Park, Sungsu [National Center for Atmospheric Research, Boulder, CO (United States); Dennis, John [National Center for Atmospheric Research, Boulder, CO (United States); Saravanan, R. [National Center for Atmospheric Research, Boulder, CO (United States); Schneider, Niklas [National Center for Atmospheric Research, Boulder, CO (United States); Kwon, Young-Oh [National Center for Atmospheric Research, Boulder, CO (United States)

2015-06-11

This project aims to improve long term global climate simulations by resolving ocean mesoscale activity and the corresponding response in the atmosphere. The main computational objectives are; i) to perform and assess Community Earth System Model (CESM) simulations with the new Community Atmospheric Model (CAM) spectral element dynamical core; ii) use static mesh refinement to focus on oceanic fronts; iii) develop a new Earth System Modeling tool to investigate the atmospheric response to fronts by selectively filtering surface flux fields in the CESM coupler. The climate research objectives are 1) to improve the coupling of ocean fronts and the atmospheric boundary layer via investigations of dependency on model resolution and stability functions: 2) to understand and simulate the ensuing tropospheric response that has recently been documented in observations: and 3) to investigate the relationship of ocean frontal variability to low frequency climate variability and the accompanying storm tracks and extremes in high resolution simulations. This is a collaborative multi-institution project consisting of computational scientists, climate scientists and climate model developers. It specifically aims at DOE objectives of advancing simulation and predictive capability of climate models through improvements in resolution and physical process representation.

Ocean transport and variability studies of the South Pacific, Southern, and Indian Oceans

Science.gov (United States)

Church, John A.; Cresswell, G. R.; Nilsson, C. S.; Mcdougall, T. J.; Coleman, R.; Rizos, C.; Penrose, J.; Hunter, J. R.; Lynch, M. J.

1991-01-01

The objectives of this study are to analyze ocean dynamics in the western South Pacific and the adjacent Southern Ocean and the eastern Indian Ocean. Specifically, our objectives for these three regions are, for the South Pacific Ocean: (1) To estimate the volume transport of the east Australian Current (EAC) along the Australian coast and in the Tasman Front, and to estimate the time variability (on seasonal and interannual time scales) of this transport. (2) To contribute to estimating the meridional heat and freshwater fluxes (and their variability) at about 30 deg S. Good estimates of the transport in the western boundary current are essential for accurate estimates of these fluxes. (3) To determine how the EAC transport (and its extension, the Tasman Front and the East Auckland Current) closes the subtropical gyre of the South Pacific and to better determine the structure at the confluence of this current and the Antarctic Circumpolar Current. (4) To examine the structure and time variability of the circulation in the western South Pacific and the adjacent Southern Ocean, particularly at the Tasman Front. For the Indian Ocean: (5) To study the seasonal interannual variations in the strength of the Leeuwin Current. (6) To monitor the Pacific-Indian Ocean throughflow and the South Equatorial and the South Java Currents between northwest Australia and Indonesia. (7) To study the processes that form the water of the permanent oceanic thermocline and, in particular, the way in which new thermocline water enters the permanent thermocline in late winter and early spring as the mixed layer restratifies. For the Southern Ocean: (8) To study the mesoscale and meridional structure of the Southern Ocean between 150 deg E and 170 deg E; in particular, to describe the Antarctic frontal system south of Tasmania and determine its interannual variability; to estimate the exchanges of heat, salt, and other properties between the Indian and Pacific Oceans; and to investigate the

Resolution of fine biological structure including small narcomedusae across a front in the Southern California Bight

Science.gov (United States)

McClatchie, Sam; Cowen, Robert; Nieto, Karen; Greer, Adam; Luo, Jessica Y.; Guigand, Cedric; Demer, David; Griffith, David; Rudnick, Daniel

2012-04-01

We sampled a front detected by SST gradient, ocean color imagery, and a Spray glider south of San Nicolas Island in the Southern California Bight between 14 and 18 October 2010. We sampled the front with an unusually extensive array of instrumentation, including the Continuous Underway Fish Egg Sampler (CUFES), the undulating In Situ Ichthyoplankton Imaging System (ISIIS) (fitted with temperature, salinity, oxygen, and fluorescence sensors), multifrequency acoustics, a surface pelagic trawl, a bongo net, and a neuston net. We found higher fluorescence and greater cladoceran, decapod, and euphausiid densities in the front, indicating increased primary and secondary production. Mesopelagic fish were most abundant in oceanic waters to the west of the front, market squid were abundant in the front associated with higher krill and decapod densities, and jack mackerel were most common in the front and on the shoreward side of the front. Egg densities peaked to either side of the front, consistent with both offshore (for oceanic squid and mesopelagic fish) and shelf origins (for white croaker and California halibut). We discovered unusually high concentrations of predatory narcomedusae in the surface layer of the frontal zone. Potential ichthyoplankton predators were more abundant either in the front (decapods, euphausiids, and squid) or shoreward of the front (medusae, chaetognaths, and jack mackerel). For pelagic fish like sardine, which can thrive in less productive waters, the safest place to spawn would be offshore because there are fewer potential predators.

Fronts, water masses and heat content variability in the Western Indian sector of the Southern Ocean during austral summer 2004

Digital Repository Service at National Institute of Oceanography (India)

AnilKumar, N.; Luis, A.J.; Somayajulu, Y.K.; RameshBabu, V.; Dash, M.K.; Pednekar, S.M.; Babu, K.N.; Sudhakar, M.; Pandey, P.C.

of the southern sector of the Indian Ocean (Fu, 1986; Nagata et al, 1988; Park et al, 1993; Orsi et al., 1995; Belkin and Gordon, 1996; Sparrow et al., 1996; Holliday and Read, 1998; Park et al., 1998; Reid, 2003) which emphasized that the areas west... to classify each front based on exact change in its characteristic parameters, the criteria adopted by elsewhere were considered (Peterson and Whitworth, 1989; Orsi et al., 1993; Read and Pollard,1993; Orsi et al.,1995; Belkin and Gordon, 1996; Sparrow 4 et...

The Policy Implementation in Development Water Front City in District Senapelan Pekanbaru

Directory of Open Access Journals (Sweden)

Panca Setyo Prihatin

2013-02-01

Full Text Available Structuring urban areas, especially the Pekanbaru City, is necessary given the problem of development of Pekanbaru City is more and more complex and highly in need of a better arrangement, especially concerning on the improvement of the environment (Water Front City in Siak River surroundings. This is a descriptive qualitative research with population sample of the Office of Settlement and Regional Infrastructure of Pekanbaru City, Senapelan District Government, NGOs, community leaders, and private parties. Data are collected through interview, observation and documentation, which is then analyzed using qualitative analysis technique. This research finds that the policy of the development of Water Front City at Village Kampung Baru sub-district Senapelan Pekanbaru is not implemented optimally. This situation can be seen through a variety of indicators related to the implementation of development policies of Water Front City at Village Kampung Baru sub-district Senapelan Pekanbaru in that the effect of interest policies, benefits, desire for change, the process of decision-making, implementing programs and supporting resources have not been implemented effectively. The curbing factors in implementing development policies in the District Water Front City Senapelan Pekanbaru are mostly due to the lack of human resources, process of compensation and other inadequate financing, and managerial instruments that are unsupported to the implementation of development programs of Water Front City at Village Kampung Baru sub-district Senapelan Pekanbaru.

Spontaneous Wave Generation from Submesoscale Fronts and Filaments

Science.gov (United States)

Shakespeare, C. J.; Hogg, A.

2016-02-01

Submesoscale features such as eddies, fronts, jets and filaments can be significant sources of spontaneous wave generation at the ocean surface. Unlike near-inertial waves forced by winds, these spontaneous waves are typically of higher frequency and can propagate through the thermocline, whereupon they break and drive mixing in the ocean interior. Here we investigate the spontaneous generation, propagation and subsequent breaking of these waves using a combination of theory and submesoscale resolving numerical models. The mechanism of generation is nearly identical to that of lee waves where flow is deflected over a rigid obstacle on the sea floor. Here, very sharp fronts and filaments of order 100m width moving in the submesoscale surface flow generate "surface lee waves" by presenting an obstacle to the surrounding stratified fluid. Using our numerical model we quantify the net downward wave energy flux from the surface, and where it is dissipated in the water column. Our results suggest an alternative to the classical paradigm where the energy associated with mixing in the ocean interior is sourced from bottom-generated lee waves.

Evaluation of Front Morphological Development of Reactive Solute Transport Using Behavior Diagrams

Directory of Open Access Journals (Sweden)

Jui-Sheng Chen

2009-01-01

Full Text Available While flowing through porous medium, ground water flow dissolves minerals thereby in creasing medium porosity and ultimately permeability. Reactive fluid flows preferentially into highly permeable zones, which are therefore dissolved most rapidly, producing a further preferential permeability enhancement. Accordingly, slight non-uniformities present in porous medium can be amplified and lead to fingering reaction fronts. The objective of this study is to investigate dissolution-induced porosity changes on reaction front morphology in homogeneous porous medium with two non-uniformities. Four controlling parameters, including up stream pressure gradient, reaction rate constant, non-uniformities spacing and non-uniformity strength ratio are comprehensively considered. By using a modified version of the numerical code, NSPCRT, to conduct a series of numerical simulations, front behavior diagrams are constructed to illustrate the morphologies of reaction fronts under various combinations of these four factors. Simulation results indicate that the two non-uniformities are inhibited into a planar front under low up stream pressure gradient, merge into a single-fingering front under inter mediate up stream pressure gradient, or grow into a double-fingers front under high up stream pressure gradient. More over, the two non-uniformities tend to develop intoadouble-fingering front as the non-uniformity strength ratio in creases from 0.2 to 1.0, and merge into a single-fingering front while the non-uniformity strength ratio in creases from 1.0 to 1.8. When the reaction rate constant is small, the two non-uniformities merge into a single front. Reaction rate constant significantly affects front advancing velocity. The front advancing velocity decreases with the reaction rate constant. Based on these results, front behavior diagrams which de fine the morphologies of the reaction fronts for these four parameters are constructed. Moreover, non

Seasonal variability of thermal fronts in the northern South China Sea from satellite data

Science.gov (United States)

Wang, Dongxiao; Liu, Yun; Qi, Yiquan; Shi, Ping

The 8-year (1991-1998) Pathfinder sea surface temperature data have been applied here to produce the objectively derived seasonality of the oceanic thermal fronts in the northern South China Sea from 17°N to 25°N. Several fronts have been clearly distinguished, namely, Fujian and Guangdong Coastal Water, Pear River Estuary Coastal, Taiwan Bank, Kuroshio Intrusion, Hainan Island East Coast and Tonkin Gulf Coastal fronts. The frontal patterns in winter, spring and summer are quite similar, whereas individual fronts display different modes of seasonal variability due to different mechanisms favoring those fronts.

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean

International Nuclear Information System (INIS)

1990-01-01

The proposed COPS (Coastal Ocean Prediction Systems) program is concerned with combining numerical models with observations (through data assimilation) to improve our predictive knowledge of the coastal ocean. It is oriented toward applied research and development and depends upon the continued pursuit of basic research in programs like COOP (Coastal Ocean Processes); i.e., to a significant degree it is involved with ''technology transfer'' from basic knowledge to operational and management applications. This predictive knowledge is intended to address a variety of societal problems: (1) ship routing, (2) trajectories for search and rescue operations, (3) oil spill trajectory simulations, (4) pollution assessments, (5) fisheries management guidance, (6) simulation of the coastal ocean's response to climate variability, (7) calculation of sediment transport, (8) calculation of forces on structures, and so forth. The initial concern is with physical models and observations in order to provide a capability for the estimation of physical forces and transports in the coastal ocean. For all these applications, there are common needs for physical field estimates: waves, tides, currents, temperature, and salinity, including mixed layers, thermoclines, fronts, jets, etc. However, the intent is to work with biologists, chemists, and geologists in developing integrated multidisciplinary prediction systems as it becomes feasible to do so. From another perspective, by combining observations with models through data assimilation, a modern approach to monitoring is provided through whole-field estimation

On the role of atmospheric forcing on upper ocean physics in the Southern Ocean and biological impacts

Science.gov (United States)

Carranza, Magdalena M.

The Southern Ocean (SO) plays a key role in regulating climate by absorbing nearly half of anthropogenic carbon dioxide (CO2). Both physical and biogeochemical processes contribute to the net CO2 sink. As a result of global warming and ozone depletion, westerly winds have increased, with consequences for upper ocean physics but little is known on how primary producers are expected to respond to changes in atmospheric forcing. This thesis addresses the impact of atmospheric forcing on upper ocean dynamics and phytoplankton bloom development in the SO on synoptic storm scales, combining a broad range of observations derived from satellites, reanalysis, profiling floats and Southern elephant seals. On atmospheric synoptic timescales (2-10 days), relevant for phytoplankton growth and accumulation, wind speed has a larger impact on satellite Chl-a variability than surface heat fluxes or wind stress curl. In summer, strong winds are linked to deep mixed layers, cold sea surface temperatures and enhanced satellite chlorophyll-a (Chl-a), which suggest wind-driven entrainment plays a role in sustaining phytoplankton blooms at the surface. Subsurface bio-optical data from floats and seals reveal deep Chl-a fluorescence maxima (DFM) are ubiquitous in summer and tend to sit at the base of the mixed layer, but can occur in all seasons. The fact that wind speed and Chl-a correlations are maximal at zero lag time (from daily data) and incubation experiments indicate phytoplankton growth occurs 3-4 days after iron addition, suggests high winds in summer entrain Chl-a from a subsurface maximum. Vertical profiles also reveal Chl-a fluorescence unevenness within hydrographically defined mixed layers, suggesting the biological timescales of adaptation through the light gradient (i.e. growth and/or photoacclimation) are often faster than mixing timescales, and periods of quiescence between storms are long enough for biological gradients to form within the homogeneous layer in density

Oceanographic data collected from Tansy Point (USCG front range board) by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 1996-09-05 to 2014-10-01 (NCEI Accession 0162189)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162189 contains navigational and physical data collected at Tansy Point (USCG front range board), a fixed station in the Columbia River estuary -...

Development of Novel Front Contract Pastes for Crystalline Silicon Solar Cells

Energy Technology Data Exchange (ETDEWEB)

Duty, C.; Jellison, D. G.E. P.; Joshi, P.

2012-04-05

In order to improve the efficiencies of silicon solar cells, paste to silicon contact formation mechanisms must be more thoroughly understood as a function of paste chemistry, wafer properties and firing conditions. Ferro Corporation has been involved in paste development for over 30 years and has extensive expertise in glass and paste formulations. This project has focused on the characterization of the interface between the top contact material (silver paste) and the underlying silicon wafer. It is believed that the interface between the front contact silver and the silicon wafer plays a dominant role in the electrical performance of the solar cell. Development of an improved front contact microstructure depends on the paste chemistry, paste interaction with the SiNx, and silicon (“Si”) substrate, silicon sheet resistivity, and the firing profile. Typical front contact ink contains silver metal powders and flakes, glass powder and other inorganic additives suspended in an organic medium of resin and solvent. During fast firing cycles glass melts, wets, corrodes the SiNx layer, and then interacts with underlying Si. Glass chemistry is also a critical factor in the development of an optimum front contact microstructure. Over the course of this project, several fundamental characteristics of the Ag/Si interface were documented, including a higher-than-expected distribution of voids along the interface, which could significantly impact electrical conductivity. Several techniques were also investigated for the interfacial analysis, including STEM, EDS, FIB, EBSD, and ellipsometry.

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean. Volume 1: Strategic summary

Energy Technology Data Exchange (ETDEWEB)

1990-05-15

The proposed COPS (Coastal Ocean Prediction Systems) program is concerned with combining numerical models with observations (through data assimilation) to improve our predictive knowledge of the coastal ocean. It is oriented toward applied research and development and depends upon the continued pursuit of basic research in programs like COOP (Coastal Ocean Processes); i.e., to a significant degree it is involved with ``technology transfer`` from basic knowledge to operational and management applications. This predictive knowledge is intended to address a variety of societal problems: (1) ship routing, (2) trajectories for search and rescue operations, (3) oil spill trajectory simulations, (4) pollution assessments, (5) fisheries management guidance, (6) simulation of the coastal ocean`s response to climate variability, (7) calculation of sediment transport, (8) calculation of forces on structures, and so forth. The initial concern is with physical models and observations in order to provide a capability for the estimation of physical forces and transports in the coastal ocean. For all these applications, there are common needs for physical field estimates: waves, tides, currents, temperature, and salinity, including mixed layers, thermoclines, fronts, jets, etc. However, the intent is to work with biologists, chemists, and geologists in developing integrated multidisciplinary prediction systems as it becomes feasible to do so. From another perspective, by combining observations with models through data assimilation, a modern approach to monitoring is provided through whole-field estimation.

Mode Water Formation via Cabbeling and Submesoscale Lateral Mixing at a Strained Thermohaline Front

Science.gov (United States)

Thomas, L. N.; Shakespeare, C. J.

2014-12-01

Mode waters play an important role in interannual climate variability through the temporary storage of heat and carbon in the ocean. The mechanisms explaining their formation are not well understood but appear to be shaped by the dynamics of the ocean fronts that mark their poleward extent. We explore a mode water formation mechanism that has a clear connection to fronts and involves cabbeling. Cabbeling refers to the process by which two water masses of equal density but different temperature and salinity are combined to create a new, denser water mass, as a result of nonlinearities in the equation of state for seawater. The work is motivated in part by recent observations of an extremely sharp, density-compensated front at the north wall of the Gulf Stream, the boundary between the subtropical and subpolar gyres. Here, the inter-gyre salinity/temperature difference is compressed into a span of a few kilometers, making the flow susceptible to cabbeling. The sharpness of the front is caused by frontogenetic strain, which is presumably balanced by submesoscale lateral mixing processes. We study this balance with a simple analytical model of a thermohaline front forced by uniform strain and derive a scaling for the amount of water mass transformation resulting from the ensuing cabbeling. The theory suggests that this mechanism could be responsible for persistent, hence significant, mode water formation. As such, it represents a submesoscale process that impacts the ocean on basin scales that should be resolved or parameterized in realistic numerical simulations.

Ocean Technology Development Tank

Data.gov (United States)

Federal Laboratory Consortium — The new SWFSC laboratory in La Jolla incorporates a large sea- and fresh-water Ocean Technology Development Tank. This world-class facility expands NOAA's ability to...

Distribution patterns of oceanic micronekton at seamounts and hydrographic fronts of the subtropical Atlantic Ocean

OpenAIRE

Diekmann, Rabea

2004-01-01

In the past the oceanic environment has often been compared with terrestrial deserts and until today relatively little is known about the ecology of the high seas. Within the present study pelagic oceanic communities of cephalopods and fish in the subtropical North Atlantic were investigated, and it was analysed at different spatial scales how these communities varied in response to physical gradients and hydrographic processes. First, the influence of the subtropical convergence zone in the ...

Use of Real Time Satellite Infrared and Ocean Color to Produce Ocean Products

Science.gov (United States)

Roffer, M. A.; Muller-Karger, F. E.; Westhaver, D.; Gawlikowski, G.; Upton, M.; Hall, C.

2014-12-01

Real-time data products derived from infrared and ocean color satellites are useful for several types of users around the world. Highly relevant applications include recreational and commercial fisheries, commercial towing vessel and other maritime and navigation operations, and other scientific and applied marine research. Uses of the data include developing sampling strategies for research programs, tracking of water masses and ocean fronts, optimizing ship routes, evaluating water quality conditions (coastal, estuarine, oceanic), and developing fisheries and essential fish habitat indices. Important considerations for users are data access and delivery mechanisms, and data formats. At this time, the data are being generated in formats increasingly available on mobile computing platforms, and are delivered through popular interfaces including social media (Facebook, Linkedin, Twitter and others), Google Earth and other online Geographical Information Systems, or are simply distributed via subscription by email. We review 30 years of applications and describe how we develop customized products and delivery mechanisms working directly with users. We review benefits and issues of access to government databases (NOAA, NASA, ESA), standard data products, and the conversion to tailored products for our users. We discuss advantages of different product formats and of the platforms used to display and to manipulate the data.

The effects of variable front persistence and intensity on mesopelagic fish communities: a comparison of three fronts in the California Current Ecosystem

Science.gov (United States)

Netburn, A. N.; Koslow, J. A.

2016-02-01

Although the strong physical gradients at fronts are primarily realized in the epipelagic, the biological impacts of frontal ecosystems can extend into mesopelagic waters. In 2008, Lara-Lopez et al. (2012) observed a significant shift in total biomass and community composition of migrating mesopelagic fishes at a strong persistent front off of the Pt. Conception area of the southern California Current Ecosystem. Through the California Current Ecosystem Long-Term Ecological Research Program, two additional intensive sampling cruises have been conducted on frontal systems in the general region. In 2011 and 2012, paired day and night midwater Matsuda-Oozeki-Hu trawls were conducted at stations located on either side of the fronts and at the fronts themselves, a suite of concurrent observations of the physical environment measured, and lower trophic levels sampled. Using satellite imagery, we estimate front duration of each of the 2008, 2011, and 2012 fronts, and investigate changes to the relative abundance and community composition across these systems, comparing the resolved patterns in 2011 and 2012 to those published from 2008. Results of this work will help address the questions: (1) What are the timescales required for front presence to impact mesopelagic fish communities? (2) Do different types of frontal systems (e.g., an eddy front vs. a "classic" front) result in different patterns of mesopelagic fish abundance and community composition? These answers will provide insight into the mechanisms of accumulation of fishes at fronts. As many mesopelagic fishes are important forage species for oceanic predators, understanding their response to the high productivity frontal systems is key to understanding ecosystem-wide impacts of fronts.

Actinobacterial community structure in the Polar Frontal waters of the Southern Ocean of the Antarctica using Geographic Information System (GIS: A novel approach to study Ocean Microbiome

Directory of Open Access Journals (Sweden)

P. Sivasankar

2018-04-01

Full Text Available Integration of microbiological data and geographical locations is necessary to understand the spatiotemporal patterns of the microbial diversity of an ecosystem. The Geographic Information System (GIS to map and catalogue the data on the actinobacterial diversity of the Southern Ocean waters was completed through sampling and analysis. Water samples collected at two sampling stations viz. Polar Front 1 (Station 1 and Polar Front 2 (Station 2 during 7th Indian Scientific Expedition to the Indian Ocean Sector of the Southern Ocean (SOE-2012-13 were used for analysis. At the outset, two different genera of Actinobacteria were recorded at both sampling stations. Streptomyces was the dominanted with the high score (> 60%, followed by Nocardiopsis (< 30% at both the sampling stations-Polar Front 1 and Polar Front 2-along with other invasive genera such as Agrococcus, Arthrobacter, Cryobacterium, Curtobacterium, Microbacterium, Marisediminicola, Rhodococcus and Kocuria. This data will help to discriminate the diversity and distribution pattern of the Actinobacteria in the Polar Frontal Region of the Southern Ocean waters. It is a novel approach useful for geospatial cataloguing of microbial diversity from extreme niches and in various environmental gradations. Furthermore, this research work will act as the milestone for bioprospecting of microbial communities and their products having potential applications in healthcare, agriculture and beneficial to mankind. Hence, this research work would have significance in creating a database on microbial communities of the Antarctic ecosystem. Keywords: Antarctica, Marine actinobacteria, Southern ocean, GIS, Polar Frontal waters, Microbiome

Trace metal fronts in European shelf waters

International Nuclear Information System (INIS)

Kremling, K.

1983-01-01

The Hebrides shelf edge area is characterized by strong horizontal salinity gradients (fronts) which mark the boundary between Scottish coastal and oceanic waters. The results presented here, obtained in summer 1981 on a transect between the open north Atlantic and the German Bight, confirm that the hydrographical front is accompanied by dramatic increases in inorganic nutrients (phosphate, silicate) and dissolved trace elements such as Cd, Cu, Mn, and 226 Ra. These data (together with measurements from North Sea regions) suggest that the trace metals are mobilized from partly reduced (organic-rich) sediments and vertically mixed into the surface waters. The regional variations evident from the transect are interpreted as being the result of the hydrography prevailing in waters around the British Isles. (author)

Remote sensing of coastal fronts and their effects on oil dispersion

Energy Technology Data Exchange (ETDEWEB)

Klemas, V

1980-01-01

The use of remote sensing techniques to determine the properties of coastal and estuarine fronts, which represent regions of discontinuities and high gradients in ocean physical parameters such as velocity and density, and to assess the influence of such fronts on oil pollutants is discussed. Results of an aircraft and boat verification study of an oil drift and spread model in Delaware Bay are indicated which illustrate the tendency of oil slicks to be attracted to frontal regions, where a denser fluid underlies a lighter fluid giving rise to an inclined interface with convergence zones. Landsat imagery of the bay acquired in order to incorporate frontal information into the interactive computer model is then presented which allows the locations of coastal fronts to be charted throughout a tidal cycle. It is noted that satellite observations of flood-associated fronts on the New Jersey side of the bay and ebb-associated fronts on the Delaware side agree with boat measurements and model predictions, and that the remote tracking of fronts by aircraft and satellites will aid in oil slick clean-up operations.

TRAINING AND DEVELOPMENT STANDARDS FOR FRONT OFFICE EMPLOYEES IN MODERN HOTEL INDUSTRY

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Ivica Batinić

2014-10-01

Full Text Available Specific requirements of modern consumer-tourists, competition, new sciences and technology have led to the emergence of new products and services in a modern hotel business as well as prescription of training and development standards for employees and managers in the hotel groups and independent hotels of higher rank. Every serious hotel, in order to survive on the tourist market, must have a separate program (standard of training and development for employees and managers. General hotel management, particularly human resource management, is fully responsible for the development and implementation of the program (standard of training and development of employees and managers. In this paper, I will write about the basic features of modern hospitality and fundamental stages of training and development of hotel employees and managers. In a particular part, I will write about front office department and training and development standards of front office employees and managers.

Effects of cold fronts on ozone in the Houston-Galveston-Brazoria Area

Science.gov (United States)

Lei, R.; Talbot, R. W.; Wang, Y.; Wang, S. C.; Estes, M. J.

2017-12-01

A cold front may have confounding effects on ozone by bringing in contaminated air masses to an area and causing lower temperatures which likely lead to low ozone production rates. Literature reports on individual cold front events showing increasing and decreasing effects on ozone. The Houston-Galveston-Brazoria (HGB) area as the energy capital of USA suffers relatively high ozone levels. The effect of cold fronts on HGB ozone in the long-term range remains unknown. Weather Prediction Center (WPC) Surface Analysis Archive from National Oceanic and Atmospheric Administration (NOAA) which records cold fronts' positions since 2003 has been employed in this study. The results show the count of cold fronts passing the HGB area shows no clear trend but great interannual variation. Cold front appearance in summer is much less than in other seasons. In general, both mean MDA8 and background ozone during cold front days increased compared non-cold front days. This increasing effect has been enhanced during post-front days and summer season. Cluster analysis on meteorological parameters shows cold front days with high precipitation or wind speed could lower the MDA8 and background ozone but the proportion of those days are low in all cold front days. It may explain why cold fronts show increasing effects on ozone in the HGB area.

Seabirds and fronts: a brief overview

OpenAIRE

Schneider, David C.

1990-01-01

Oceanographic fronts are the sites of enhanced physical and biological activity, including locally concentrated feeding by marine birds. Two general hypotheses relating marine birds to fronts have been developed. The first is that enhanced primary production at fronts increases prey supply through increased animal growth, reproduction, or immigration. The second is that prey patches develop at fronts either through behavioural responses of prey to thermal or salinity gradients, or through int...

The Contribution of Innovation Strategy Development and Implementation in Active Facilitation of Pharmaceutical Front End Innovation

DEFF Research Database (Denmark)

Aagaard, Annabeth

2012-01-01

Front end innovation (FEI) represents the first building blocks of product development, but is often regarded as a weak link in innovation literature. Various theorists emphasize that a firm’s innovation can benefit substantially by improving the front end of innovation process (Reinertsen, 1999,......-oriented longitudinal case study of a Danish pharmaceutical company. The findings and key learnings from the study are presented as propositions of how innovation strategies can be applied to actively facilitate FEI and with measurable results.......Front end innovation (FEI) represents the first building blocks of product development, but is often regarded as a weak link in innovation literature. Various theorists emphasize that a firm’s innovation can benefit substantially by improving the front end of innovation process (Reinertsen, 1999...

Marine fronts at the continental shelves of austral South America - Physical and ecological processes

Science.gov (United States)

Acha, Eduardo M.; Mianzan, Hermes W.; Guerrero, Raúl A.; Favero, Marco; Bava, José

2004-01-01

Neritic fronts are very abundant in austral South America, covering several scales of space and time. However, this region is poorly studied from a systemic point of view. Our main goal is to develop a holistic view of physical and ecological patterns and processes at austral South America, regarding frontal arrangements. Satellite information (sea surface temperature and chlorophyll concentration), and historical hydrographic data were employed to show fronts. We compiled all existing evidence (physical and biological) about fronts to identify regions defined by similar types of coastal fronts and to characterize them. Fronts in austral South America can be arranged in six zones according to their location, main forcing, key physical variables, seasonality, and enrichment mechanisms. Four zones, the Atlantic upwelling zone; the temperate estuarine zone; the Patagonian tidal zone and the Argentine shelf-break zone, occupy most of the Atlantic side. The Chile-Peru upwelling zone, on the Pacific, is the largest and best-known region. The Patagonian cold estuarine zone encompasses the tip of South America, connecting the Pacific and Atlantic oceans, and remains poorly studied. When observed at a continental scale, the Pacific coast dominated by two large frontal zones appears simplest than the Atlantic coast in terms of frontal richness. The extension of the continental shelf in the Atlantic coast allows for the development of a great diversity of mesoscale fronts. Though frontal zones we defined are extensive areas of the continental shelves, fronts inside the zones are comparatively small areas. Even so, they play a paramount role in ecological processes, allowing for high biological production; offering feeding and/or reproductive habitats for fishes, squids, and birds; acting as retention areas for larvae of benthic species; and promoting establishment of benthic invertebrates that benefit from the organic production in the frontal area.

Adaptation of an unstructured-mesh, finite-element ocean model to the simulation of ocean circulation beneath ice shelves

Science.gov (United States)

Kimura, Satoshi; Candy, Adam S.; Holland, Paul R.; Piggott, Matthew D.; Jenkins, Adrian

2013-07-01

Several different classes of ocean model are capable of representing floating glacial ice shelves. We describe the incorporation of ice shelves into Fluidity-ICOM, a nonhydrostatic finite-element ocean model with the capacity to utilize meshes that are unstructured and adaptive in three dimensions. This geometric flexibility offers several advantages over previous approaches. The model represents melting and freezing on all ice-shelf surfaces including vertical faces, treats the ice shelf topography as continuous rather than stepped, and does not require any smoothing of the ice topography or any of the additional parameterisations of the ocean mixed layer used in isopycnal or z-coordinate models. The model can also represent a water column that decreases to zero thickness at the 'grounding line', where the floating ice shelf is joined to its tributary ice streams. The model is applied to idealised ice-shelf geometries in order to demonstrate these capabilities. In these simple experiments, arbitrarily coarsening the mesh outside the ice-shelf cavity has little effect on the ice-shelf melt rate, while the mesh resolution within the cavity is found to be highly influential. Smoothing the vertical ice front results in faster flow along the smoothed ice front, allowing greater exchange with the ocean than in simulations with a realistic ice front. A vanishing water-column thickness at the grounding line has little effect in the simulations studied. We also investigate the response of ice shelf basal melting to variations in deep water temperature in the presence of salt stratification.

Simulation Tool for GNSS Ocean Surface Reflections

DEFF Research Database (Denmark)

Høeg, Per; von Benzon, Hans-Henrik; Durgonics, Tibor

2015-01-01

GNSS coherent and incoherent reflected signals have the potential of deriving large scale parameters of ocean surfaces, as barotropic variability, eddy currents and fronts, Rossby waves, coastal upwelling, mean ocean surfaceheights, and patterns of the general ocean circulation. In the reflection...... zone the measurements may deriveparameters as sea surface roughness, winds, waves, heights and tilts from the spectral measurements. Previous measurements from the top of mountains and airplanes have shown such results leading.The coming satellite missions, CYGNSS, COSMIC-2, and GEROS...

Bibliography of Research on Ocean Fronts, 1964-1984

Science.gov (United States)

1985-08-01

subtropical convergence; midtasman convergence; antarctic convergence and antarctic divergence. The search term "siome" was tried, but produced no hits ... Tabata , S. and L.F. Giovando. 1963. The seasonal thermocline at ocean weather station ’P’ during 1956 through 1959. Manus. Rep. Ser. No. 157. Fish...Res. Bd. Can. Tabata , S. and J.F.R. Gower. 1980. Comparison of ship and satellite measurements of sea surface temperatures off the Pacific Coast

Shearwater foraging in the Southern Ocean: the roles of prey availability and winds.

Directory of Open Access Journals (Sweden)

Ben Raymond

Full Text Available BACKGROUND: Sooty (Puffinus griseus and short-tailed (P. tenuirostris shearwaters are abundant seabirds that range widely across global oceans. Understanding the foraging ecology of these species in the Southern Ocean is important for monitoring and ecosystem conservation and management. METHODOLOGY/PRINCIPAL FINDINGS: Tracking data from sooty and short-tailed shearwaters from three regions of New Zealand and Australia were combined with at-sea observations of shearwaters in the Southern Ocean, physical oceanography, near-surface copepod distributions, pelagic trawl data, and synoptic near-surface winds. Shearwaters from all three regions foraged in the Polar Front zone, and showed particular overlap in the region around 140 degrees E. Short-tailed shearwaters from South Australia also foraged in Antarctic waters south of the Polar Front. The spatial distribution of shearwater foraging effort in the Polar Front zone was matched by patterns in large-scale upwelling, primary production, and abundances of copepods and myctophid fish. Oceanic winds were found to be broad determinants of foraging distribution, and of the flight paths taken by the birds on long foraging trips to Antarctic waters. CONCLUSIONS/SIGNIFICANCE: The shearwaters displayed foraging site fidelity and overlap of foraging habitat between species and populations that may enhance their utility as indicators of Southern Ocean ecosystems. The results highlight the importance of upwellings due to interactions of the Antarctic Circumpolar Current with large-scale bottom topography, and the corresponding localised increases in the productivity of the Polar Front ecosystem.

Ocean Observatories and the Integrated Ocean Observing System, IOOS: Developing the Synergy

Science.gov (United States)

Altalo, M. G.

2006-05-01

The National Office for Integrated and Sustained Ocean Observations is responsible for the planning, coordination and development of the U.S. Integrated Ocean Observing System, IOOS, which is both the U.S. contribution to GOOS as well as the ocean component of GEOSS. The IOOS is comprised of global observations as well as regional coastal observations coordinated so as to provide environmental information to optimize societal management decisions including disaster resilience, public health, marine transport, national security, climate and weather impact, and natural resource and ecosystem management. Data comes from distributed sensor systems comprising Federal and state monitoring efforts as well as regional enhancements, which are managed through data management and communications (DMAC) protocols. At present, 11 regional associations oversee the development of the observing System components in their region and are the primary interface with the user community. The ocean observatories are key elements of this National architecture and provide the infrastructure necessary to test new technologies, platforms, methods, models, and practices which, when validated, can transition into the operational components of the IOOS. This allows the IOOS to remain "state of the art" through incorporation of research at all phases. Both the observatories as well as the IOOS will contribute to the enhanced understanding of the ocean and coastal system so as to transform science results into societal solutions.

Three steps of serpentinization in an eclogitized oceanic serpentinization front (Lanzo Massif - Western Alps)

OpenAIRE

DEBRET, Baptiste; NICOLLET, christian; ANDREANI, Muriel; SCHWARTZ, Stéphane; GODARD, Marguerite

2013-01-01

The Lanzo peridotite massif is a fragment of oceanic lithosphere generated in an ocean-continent transition context and eclogitized during alpine collision. Despite the subduction history, the massif has preserved its sedimentary oceanic cover, suggesting that it may have preserved its oceanic structure. It is an exceptional case for studying the evolution of a fragment of the lithosphere from its oceanization to its subduction and then exhumation. We present a field and petrological study re...

Formation of intrathermocline eddies at ocean fronts by wind-driven destruction of potential vorticity

Science.gov (United States)

Thomas, Leif N.

2008-08-01

A mechanism for the generation of intrathermocline eddies (ITEs) at wind-forced fronts is examined using a high resolution numerical simulation. Favorable conditions for ITE formation result at fronts forced by "down-front" winds, i.e. winds blowing in the direction of the frontal jet. Down-front winds exert frictional forces that reduce the potential vorticity (PV) within the surface boundary in the frontal outcrop, providing a source for the low-PV water that is the materia prima of ITEs. Meandering of the front drives vertical motions that subduct the low-PV water into the pycnocline, pooling it into the coherent anticyclonic vortex of a submesoscale ITE. As the fluid is subducted along the outcropping frontal isopycnal, the low-PV water, which at the surface is associated with strongly baroclinic flow, re-expresses itself as water with nearly zero absolute vorticity. This generation of strong anticyclonic vorticity results from the tilting of the horizontal vorticity of the frontal jet, not from vortex squashing. During the formation of the ITE, high-PV water from the pycnocline is upwelled alongside the subducting low-PV surface water. The positive correlation between the ITE's velocity and PV fields results in an upward, along-isopycnal eddy PV flux that scales with the surface frictional PV flux driven by the wind. The relationship between the eddy and wind-induced frictional PV flux is nonlocal in time, as the eddy PV flux persists long after the wind forcing is shut off. The ITE's PV flux affects the large-scale flow by driving an eddy-induced transport or bolus velocity down the outcropping isopycnal layer with a magnitude that scales with the Ekman velocity.

The role of atmospheric boundary layer-surface interactions on the development of coastal fronts

Directory of Open Access Journals (Sweden)

D. Malda

2007-03-01

Full Text Available Frictional convergence and thermal difference between land and sea surface are the two surface conditions that govern the intensity and evolution of a coastal front. By means of the mesoscale model MM5, we investigate the influence of these two processes on wind patterns, temperature and precipitation amounts, associated with a coastal front, observed on the west coast of The Netherlands in the night between 12 and 13 August 2004. The mesoscale model MM5 is further compared with available observations and the results of two operational models (ECMWF and HIRLAM. HIRLAM is not capable to reproduce the coastal front, whereas ECMWF and MM5 both calculate precipitation for the coastal region. The precipitation pattern, calculated by MM5, agrees satisfactorily with the accumulated radar image. The failure of HIRLAM is mainly due to a different stream pattern at the surface and consequently, a different behaviour of the frictional convergence at the coastline.

The sensitivity analysis of frictional convergence is carried out with the MM5 model, by varying land surface roughness length (z₀. For the sensitivity analysis of thermal difference between sea and land surface, we changed the sea surface temperature (SST. Increasing surface roughness implies stronger convergence near the surface and consequently stronger upward motions and intensification of the development of the coastal front. Setting land surface roughness equal to the sea surface roughness means an elimination of frictional convergence and results in a diminishing coastal front structure of the precipitation pattern. The simulation with a high SST produces much precipitation above the sea, but less precipitation in the coastal area above land. A small increment of the SST results in larger precipitation amounts above the sea; above land increments are calculated for areas near the coast. A decrease of the SST shifts the precipitation maxima inland, although the

The role of atmospheric boundary layer-surface interactions on the development of coastal fronts

Directory of Open Access Journals (Sweden)

D. Malda

2007-03-01

Full Text Available Frictional convergence and thermal difference between land and sea surface are the two surface conditions that govern the intensity and evolution of a coastal front. By means of the mesoscale model MM5, we investigate the influence of these two processes on wind patterns, temperature and precipitation amounts, associated with a coastal front, observed on the west coast of The Netherlands in the night between 12 and 13 August 2004. The mesoscale model MM5 is further compared with available observations and the results of two operational models (ECMWF and HIRLAM. HIRLAM is not capable to reproduce the coastal front, whereas ECMWF and MM5 both calculate precipitation for the coastal region. The precipitation pattern, calculated by MM5, agrees satisfactorily with the accumulated radar image. The failure of HIRLAM is mainly due to a different stream pattern at the surface and consequently, a different behaviour of the frictional convergence at the coastline. The sensitivity analysis of frictional convergence is carried out with the MM5 model, by varying land surface roughness length (z0. For the sensitivity analysis of thermal difference between sea and land surface, we changed the sea surface temperature (SST. Increasing surface roughness implies stronger convergence near the surface and consequently stronger upward motions and intensification of the development of the coastal front. Setting land surface roughness equal to the sea surface roughness means an elimination of frictional convergence and results in a diminishing coastal front structure of the precipitation pattern. The simulation with a high SST produces much precipitation above the sea, but less precipitation in the coastal area above land. A small increment of the SST results in larger precipitation amounts above the sea; above land increments are calculated for areas near the coast. A decrease of the SST shifts the precipitation maxima inland, although the precipitation amounts

Energy Optimal Path Planning: Integrating Coastal Ocean Modelling with Optimal Control

Science.gov (United States)

Subramani, D. N.; Haley, P. J., Jr.; Lermusiaux, P. F. J.

2016-02-01

A stochastic optimization methodology is formulated for computing energy-optimal paths from among time-optimal paths of autonomous vehicles navigating in a dynamic flow field. To set up the energy optimization, the relative vehicle speed and headings are considered to be stochastic, and new stochastic Dynamically Orthogonal (DO) level-set equations that govern their stochastic time-optimal reachability fronts are derived. Their solution provides the distribution of time-optimal reachability fronts and corresponding distribution of time-optimal paths. An optimization is then performed on the vehicle's energy-time joint distribution to select the energy-optimal paths for each arrival time, among all stochastic time-optimal paths for that arrival time. The accuracy and efficiency of the DO level-set equations for solving the governing stochastic level-set reachability fronts are quantitatively assessed, including comparisons with independent semi-analytical solutions. Energy-optimal missions are studied in wind-driven barotropic quasi-geostrophic double-gyre circulations, and in realistic data-assimilative re-analyses of multiscale coastal ocean flows. The latter re-analyses are obtained from multi-resolution 2-way nested primitive-equation simulations of tidal-to-mesoscale dynamics in the Middle Atlantic Bight and Shelbreak Front region. The effects of tidal currents, strong wind events, coastal jets, and shelfbreak fronts on the energy-optimal paths are illustrated and quantified. Results showcase the opportunities for longer-duration missions that intelligently utilize the ocean environment to save energy, rigorously integrating ocean forecasting with optimal control of autonomous vehicles.

Underwater fiber-wireless communication with a passive front end

Science.gov (United States)

Xu, Jing; Sun, Bin; Lyu, Weichao; Kong, Meiwei; Sarwar, Rohail; Han, Jun; Zhang, Wei; Deng, Ning

2017-11-01

We propose and experimentally demonstrate a novel concept on underwater fiber-wireless (Fi-Wi) communication system with a fully passive wireless front end. A low-cost step-index (SI) plastic optical fiber (POF) together with a passive collimating lens at the front end composes the underwater Fi-Wi architecture. We have achieved a 1.71-Gb/s transmission at a mean BER of 4.97 × 10-3 (1.30 × 10-3 when using power loading) over a 50-m SI-POF and 2-m underwater wireless channel using orthogonal frequency division multiplexing (OFDM). Although the wireless part is very short, it actually plays a crucial role in practical underwater implementation, especially in deep sea. Compared with the wired solution (e.g. using a 52-m POF cable without the UWOC part), the proposed underwater Fi-Wi scheme can save optical wet-mate connectors that are sophisticated, very expensive and difficult to install in deep ocean. By combining high-capacity robust POF with the mobility and ubiquity of underwater wireless optical communication (UWOC), the proposed underwater Fi-Wi technology will find wide application in ocean exploration.

Mesoscale eddies in the Subantarctic Front-Southwest Atlantic

Directory of Open Access Journals (Sweden)

Pablo D. Glorioso

2005-12-01

Full Text Available Satellite and ship observations in the southern southwest Atlantic (SSWA reveal an intense eddy field and highlight the potential for using continuous real-time satellite altimetry to detect and monitor mesoscale phenomena with a view to understanding the regional circulation. The examples presented suggest that mesoscale eddies are a dominant feature of the circulation and play a fundamental role in the transport of properties along and across the Antarctic Circumpolar Current (ACC. The main ocean current in the SSWA, the Falkland-Malvinas Current (FMC, exhibits numerous embedded eddies south of 50°S which may contribute to the patchiness, transport and mixing of passive scalars by this strong, turbulent current. Large eddies associated with meanders are observed in the ACC fronts, some of them remaining stationary for long periods. Two particular cases are examined using a satellite altimeter in combination with in situ observations, suggesting that cross-frontal eddy transport and strong meandering occur where the ACC flow intensifies along the sub-Antarctic Front (SAF and the Southern ACC Front (SACCF.

Technical Progress and Development Directions of Oceanic Spatial Information Datum

Directory of Open Access Journals (Sweden)

BAO Jingyang

2017-10-01

Full Text Available This paper briefly analyzes the basic development and technical situation of oceanic spatial information datum, reviews the main processes of oceanic vertical datum and correlative oceanic tidal study, such as improvement and perfect methods of determining tidal station vertical datum, realizing form of vertical datum controlled by tidal station, effect on maintaining vertical datum by long-term tidal station, oceanic tidal model establishing, and also construction and transformation of tidal datum, and then forecasts the key development directions of oceanic spatial information datum on high-accuracy marine position service, vertical datum and the transferring model refinement and spatial datum application.

/sup 226/Ra in the western Indian Ocean

Energy Technology Data Exchange (ETDEWEB)

Chung, Y.

1987-09-01

/sup 226/Ra profiles have been measured in the western Indian Ocean as part of the 1977-78 Indian Ocean GEOSECS program. These profiles show a general increase in deep and bottom water Ra concentration from the Circumpolar region to the Arabian Sea. A deep Ra maximum which originates in the Arabian Sea and in the Somali basin at about 3000 m depth spreads southward into the Mascarene basin and remains discernible in the Madagascar and Crozet basins. In the western Indian Ocean, the cold Antarctic Bottom Water spreads northward under the possibly southward-flowing deep water, forming a clear benthic front along the Crozet basin across the Southwest Indian Ridge into the Madagascar and Mascarene basins. The Antarctic Bottom Water continues to spread farther north to the Somali basin through the Amirante Passage at 10/sup 0/S as a western boundary current. The benthic front and other characteristic features in the western Indian Ocean are quite similar to those observed in the western Pacific where the benthic front as a distinctive feature was first described by Craig et al. Across the Mid-Indian Ridge toward the Ceylon abyssal plain near the triple junction, Ra profiles display a layered structure, reflecting the topographic effect of the mid-ocean ridge system on the mixing and circulation of the deep and bottom waters. Both Ra and Si show a deep maximum north of the Madagascar Basin. Linear relationships between these two elements are observed in the deep and bottom water with slopes increasing northward. This suggests a preferential input of Ra over Si from the bottom sediments of the Arabian Sea and also from the flank sediments of the Somali basin.

Development and Demonstration of a Magnesium-Intensive Vehicle Front-End Substructure

Energy Technology Data Exchange (ETDEWEB)

Logan, Stephen D. [United States Automotive Materials Partnership LLC, Southfield, MI (United States); Forsmark, Joy H. [United States Automotive Materials Partnership LLC, Southfield, MI (United States); Osborne, Richard [United States Automotive Materials Partnership LLC, Southfield, MI (United States)

2016-07-01

This project is the final phase (designated Phase III) of an extensive, nine-year effort with the objectives of developing a knowledge base and enabling technologies for the design, fabrication and performance evaluation of magnesium-intensive automotive front-end substructures intended to partially or completely replace all-steel comparators, providing a weight savings approaching 50% of the baseline. Benefits of extensive vehicle weight reduction in terms of fuel economy increase, extended vehicle range, vehicle performance and commensurate reductions in greenhouse gas emissions are well known. An exemplary vehicle substructure considered by the project is illustrated in Figure 1, along with the exterior vehicle appearance. This unibody front-end “substructure” is one physical objective of the ultimate design and engineering aspects established at the outset of the larger collective effort.

Aquantis Ocean Current Turbine Development Project Report

Energy Technology Data Exchange (ETDEWEB)

Fleming, Alex J.

2014-08-23

The Aquantis® Current Plane (“C-Plane”) technology developed by Dehlsen Associates, LLC (DA) and Aquantis, Inc. is an ocean current turbine designed to extract kinetic energy from ocean currents. The technology is capable of achieving competitively priced base-load, continuous, and reliable power generation from a source of renewable energy not before possible in this scale or form.

SI-Ocean Strategic technology agenda for the ocean energy sector: From development to market

OpenAIRE

MAGAGNA DAVIDE; TZIMAS Evangelos; HANMER Clare; BADCOCK-BROE Abbie; MACGILLIVRAY Andy; JEFFREY Henry; RAVENTOS Alex

2014-01-01

This paper focuses on the development of the ocean energy sector, identifying the necessary steps that are required in order to facilitate the development and deployment of ocean energy technologies towards the formation of a viable and successful industry. Europe, in particular the Atlantic Arc region, has a vast wave and tidal energy resource, which could supply a significant part of the European electricity demand and play an important role in the future European energy mix. The ...

Rapid Convergence and Subduction at the Intersections of Fronts

Science.gov (United States)

D'Asaro, E. A.

2016-12-01

An array of 300 surface drifters drogued to follow the top 0.6m of the ocean were deployed in the northern Gulf of Mexico near the Deep Water Horizon spill site in January of 2016. As expected, the array spread from its initial 15x15km scale with the second moment increasing at a rate roughly consistent with historical dispersion curves. More surprisingly, a large fraction of the drifters accumulated within a km-scale submesoscale eddy and grouped into clusters often only a few meters apart. This occurred due to surface convergence, as opposed to purely confluence, with convergence rates of many f feeding downward-going subduction zones with vertical velocities of a few centimeters per second. These convergences preferentially occurred at density fronts and in particular at junctions of density fronts on the periphery of submesoscale eddies. These observations complement the traditional view of lateral dispersion of surface particles by mesoscale eddies with a competing submesocale convergence and provide direct observations of the strong vertical exchanges associated with submesoscale eddies and fronts.

High-velocity basal sediment package atop oceanic crust, offshore Cascadia: Impacts on plate boundary processes and fluid migration

Science.gov (United States)

Peterson, D. E.; Keranen, K. M.

2017-12-01

Differences in fluid pressure and mechanical properties at megathrust boundaries in subduction zones have been proposed to create varying seismogenic behavior. In Cascadia, where large ruptures are possible but little seismicity occurs presently, new seismic transects across the deformation front (COAST cruise; Holbrook et al., 2012) image an unusually high-wavespeed sedimentary unit directly overlying oceanic crust. Wavespeed increases before sediments reach the deformation front, and the well-laminated unit, consistently of 1 km thickness, can be traced for 50 km beneath the accretionary prism before imaging quality declines. Wavespeed is modeled via iterative prestack time migration (PSTM) imaging and increases from 3.5 km/sec on the seaward end of the profile to >5.0 km/s near the deformation front. Landward of the deformation front, wavespeed is low along seaward-dipping thrust faults in the Quaternary accretionary prism, indicative of rapid dewatering along faults. The observed wavespeed of 5.5 km/sec just above subducting crust is consistent with porosity intersects the plate boundary at an oblique angle and changes the degree of hydration of the oceanic plate as it subducts within our area. Fluid flow out of oceanic crust is likely impeded by the low-porosity basal sediment package except along the focused thrust faults. Decollements are present at the top of oceanic basement, at the top of the high-wavespeed basal unit, and within sedimentary strata at higher levels; the decollement at the top of oceanic crust is active at the toe of the deformation front. The basal sedimentary unit appears to be mechanically strong, similar to observations from offshore Sumatra, where strongly consolidated sediments at the deformation front are interpreted to facilitate megathrust rupture to the trench (Hupers et al., 2017). A uniformly strong plate interface at Cascadia may inhibit microseismicity while building stress that is released in great earthquakes.

RPC performance vs. front-end electronics

International Nuclear Information System (INIS)

Cardarelli, R.; Aielli, G.; Camarri, P.; Di Ciaccio, A.; Di Stante, L.; Liberti, B.; Pastori, E.; Santonico, R.; Zerbini, A.

2012-01-01

Moving the amplification from the gas to the front-end electronics was a milestone in the development of Resistive Plate Chambers. Here we discuss the historical evolution of RPCs and we show the results obtained with newly developed front-end electronics with threshold in the fC range.

Ocean control of the breeding regime of the sooty tern in the southwest Indian Ocean

Science.gov (United States)

Jaquemet, S.; Le Corre, M.; Quartly, G. D.

2007-01-01

Food availability, which is often seasonal, is regarded as a key factor in the breeding success of seabirds. In oceanic tropical areas, the resources are mostly patchy and ephemeral at the surface, and the seasonality is less marked than at higher latitudes. Such a situation influences greatly the breeding strategies of the oceanic seabird species. We conducted a comparative study of the breeding phenology of the sooty tern ( Sterna fuscata) in relation to the local and regional oceanographic conditions around the four major colonies (Europa, Juan de Nova, Lys and Bird Islands) of the southwest Indian Ocean. Over the 1997-2003 period, around all the studied locations, the sea-surface temperature (SST) and the chlorophyll concentration in the Mozambique Channel and the Seychelles area showed clear seasonal differences related to the southern climate and the monsoon phenomena. The breeding activity is synchronized at each studied colony, but the timings are very different. Seasonal reproduction occurs in austral winter at Europa and Bird Island and in austral summer at Juan de Nova; at Lys Island the reproduction is non-seasonal. For the seasonal colonies, there is a large monthly change in SST just before the beginning of reproduction, which is a proxy indicating the annual phytoplankton bloom. This variation is accompanied by the development of oceanic features such as fronts that favour aggregation of prey, and may also play an important role in the presence of schools of surface tuna, which are very important for the foraging success of sooty terns. Conversely, around Lys Island the seasonal variations of the marine environment do not lead to pronounced development of oceanic structures, and consequently, the longer-lasting phytoplankton bloom could explain the non-seasonal breeding regime there. Further studies will help discern the advantages and disadvantages of seasonal and non-seasonal reproduction regime in response to unpredictable fluctuations of the

Light-Front Holography and the Light-Front Schrodinger Equation

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; de Teramond, Guy

2012-08-15

One of the most important nonperturbative methods for solving QCD is quantization at fixed light-front time {tau} = t+z=c - Dirac's 'Front Form'. The eigenvalues of the light-front QCD Hamiltonian predict the hadron spectrum and the eigensolutions provide the light-front wavefunctions which describe hadron structure. More generally, we show that the valence Fock-state wavefunctions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schrodinger equation, with an effective confining potential U which systematically incorporates the effects of higher quark and gluon Fock states. We outline a method for computing the required potential from first principles in QCD. The holographic mapping of gravity in AdS space to QCD, quantized at fixed light-front time, yields the same light front Schrodinger equation; in fact, the soft-wall AdS/QCD approach provides a model for the light-front potential which is color-confining and reproduces well the light-hadron spectrum. One also derives via light-front holography a precise relation between the bound-state amplitudes in the fifth dimension of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. The elastic and transition form factors of the pion and the nucleons are found to be well described in this framework. The light-front AdS/QCD holographic approach thus gives a frame-independent first approximation of the color-confining dynamics, spectroscopy, and excitation spectra of relativistic light-quark bound states in QCD.

Observational description of the atmospheric and oceanic boundary layers over the Atlantic Ocean

Directory of Open Access Journals (Sweden)

Marcelo Dourado

2001-01-01

Full Text Available Time evolution of atmospheric and oceanic boundary layers are described for an upwelling region in the Atlantic Ocean located in Cabo Frio, Brazil (23°00'S, 42°08'W. The observations were obtained during a field campaign carried out by the "Instituto de Estudos do Mar Almirante Paulo Moreira", on board of the oceanographic ship Antares of the Brazilian Navy, between July 7 and 10 of 1992. The analysis shown here was based on 19 simultaneous vertical soundings of atmosphere and ocean, carried out consecutively every 4 hours. The period of observation was characterized by a passage of a cold front that penetrated in Cabo Frio on July 6. During the cold front passage the vertical extension of atmospheric (and oceanic mixed layer varied from 200 m (and 13 m to 1000 m (and 59 m. These changes occurred in the first day of observation and were followed by an increase of 1.2°C in the oceanic mixed layer temperature and by a decrease of 6 K and 6 g/kg in the virtual potential temperature and specific humidity of the atmospheric mixed layer. The short time scale variations in the ocean can be explained in terms of the substitution of cold upwelling water by warm downwelling water regime, as the surface winds shift from pre-frontal NE to post-frontal SSW during the cold front passage in Cabo Frio. The large vertical extent of the atmospheric mixed layer can be explained in terms of an intensification of the thermal mixing induced by the warming of the oceanic upper layers combined with the cooling of the lower atmospheric layers during the cold front passage. An intensification of the mechanical mixing, observed during the cold front passage, may also be contributing to the observed variations in the vertical extent of both layers.A evolução temporal das camadas limites atmosféricas e oceânicas são descritas para a região de ressurgência do Oceano Atlântico localizada em Cabo Frio. As observações foram obtidas durante a campanha de medidas

Beam front accelerators

International Nuclear Information System (INIS)

Reiser, M.

1982-01-01

An intense relativistic electron beam cannot propagate in a metal drift tube when the current exceeds the space charge limit. Very high charge density and electric field gradients (10 2 to 10 3 MV/m) develop at the beam front and the electrons are reflected. When a neutral gas or a plasma is present, collective acceleration of positive ions occur, and the resulting charge neutralization enables the beam to propagate. Experimental results, theoretical understanding, and schemes to achieve high ion energies by external control of the beam front velocity will be reviewed

Predictability of surface currents and fronts off the Mississippi Delta

International Nuclear Information System (INIS)

Walker, N.D.; Rouse, L.J.; Wiseman, W.J.

2001-01-01

The dynamic coastal region of the lower Mississippi River was examined under varying conditions of wind, river discharge and circulation patterns of the Gulf of Mexico. Nearly 7,000 deep-sea merchant vessels enter the port complex each year and the area boasts the highest concentration of offshore drilling rigs, rendering the Mississippi delta and adjacent coastal areas vulnerable to risk from oil spills. Satellite imagery has been useful in tracking movements of the Mississippi river plume as recognizable turbidity and temperature fronts are formed where river waters encounter ambient shelf waters. Oil spill modelers often base their predictions of oil movement on the surface wind field and surface currents, but past studies have indicated that this can be overly simplistic in regions affected by river flow because river fronts have significant control over the movement of oil in opposition to prevailing winds. Frontal zones, such as those found where river waters meet oceanic waters, are characterized by strong convergence of surface flow. These frontal zones can provide large and efficient traps or natural booms for spilled oil. In an effort to facilitate cleanup operations, this study made use of the National Ocean and Atmospheric Administration (NOAA) AVHRR satellite imagery of temperature and reflectance to study front locations and their variability in space and time. The main objectives were to quantify surface temperature structure and locations of fronts throughout the year using satellite image data, to map the structure of the Mississippi sediment plume and to assess the forcing factors responsible for its variability over space and time. The final objective was to use in-situ measurements of surface currents together with satellite image data to better understand surface flow in this region of strong and variable currents. It was concluded that the main factors controlling circulation in the Mississippi River outflow region are river discharge and

Sharp fronts within geochemical transport problems

International Nuclear Information System (INIS)

Grindrod, P.

1995-01-01

The authors consider some reactive geochemical transport problems in groundwater systems. When incoming fluid is in disequilibrium with the mineralogy sharp transition fronts may develop. They show that this is a generic property for a class of systems where the timescales associated with reaction and diffusion phenomena are much shorter than those associated with advective transport. Such multiple timescale problems are relevant to a variety of processes in natural systems: mathematically methods of singular perturbation theory reduce the dimension of the problems to be solved locally. Furthermore, they consider how spatial heterogeneous mineralogy can impact upon the propagation of sharp geochemical fronts. The authors developed an asymptotic approach in which they solve equations for the evolving geometry of the front and indicate how the non-smooth perturbations due to natural heterogeneity of the mineralogy on underlying ground water flow field are balanced against the smoothing effect of diffusion/dispersive processes. Fronts are curvature damped, and the results here indicate the generic nature of separate front propagation within both model (idealized) and natural (heterogeneous) geochemical systems

Identifying and tracking plumes affected by an ocean breeze in support of emergency preparedness

International Nuclear Information System (INIS)

Schwartz, P.E.

1989-01-01

To better support emergency preparedness, General Public Utilities (GPU) Nuclear has investigated the frequency of occurrence of the mesoscale ocean breeze at the Oyster Creek Nuclear Generating Station (OCNGS). Through the analysis of the horizontal wind direction and temperature patterns, simple identification of the ocean breeze along with a plume tracking procedure has been developed and incorporated into the site's emergency plant to better safeguard the public with sophisticated protective action measures in case of a nonroutine release. The ocean breeze will frequently produce wind trajectory fields within the plant's emergency planning zone that are different from the normal gradient wind flow. This could greatly alter proper protective action measures since most utilities employ straight-line trajectory air dispersion models. Knowledge of the existence of the ocean breeze and the location of the ocean breeze front become important in the results generated from the straight-line Gaussian dose calculation methodology and in the further development of a more complex dose assessment model. This paper describes the verification and existence of the sea breeze phenomenon and the incorporation of its effects into the OCNGS emergency plan

Seismic Characterization of Oceanic Water Masses, Water Mass Boundaries, and Mesoscale Eddies SE of New Zealand

Science.gov (United States)

Gorman, Andrew R.; Smillie, Matthew W.; Cooper, Joanna K.; Bowman, M. Hamish; Vennell, Ross; Holbrook, W. Steven; Frew, Russell

2018-02-01

The Subtropical and Subantarctic Fronts, which separate Subtropical, Subantarctic, and Antarctic Intermediate Waters, are diverted to the south of New Zealand by the submerged continental landmass of Zealandia. In the upper ocean of this region, large volumes of dissolved or suspended material are intermittently transported across the Subtropical Front; however, the mechanisms of such transport processes are enigmatic. Understanding these oceanic boundaries in three dimensions generally depends on measurements collected from stationary vessels and moorings. The details of these data sets, which are critical for understanding how water masses interact and mix at the fine-scale (seismic reflection images of oceanic water masses have been produced using petroleum industry data. These seismic sections clearly show three main water masses, the boundary zones (fronts) between them, and associated thermohaline fine structure that may be related to the mixing of water masses in this region. Interpretations of the data suggest that the Subtropical Front in this region is a landward-dipping zone, with a width that can vary between 20 and 40 km. The boundary zone between Subantarctic Waters and the underlying Antarctic Intermediate Waters is also observed to dip landward. Several isolated lenses have been identified on the three data sets, ranging in size from 9 to 30 km in diameter. These lenses are interpreted to be mesoscale eddies that form at relatively shallow depths along the south side of the Subtropical Front.

Redox fronts

International Nuclear Information System (INIS)

Chapman, N.; McKinley, I.; Shea, M.; Smellie, J.

1993-01-01

This article describes the investigations of redox fronts performed at the Osamu Utsumi mine. Results obtained by modelling groups on the rate of movement of the redox fronts and on the chemical reactions involved are discussed. Some of the most important rockwater interactions which occur at redox fronts can be modelled reasonably well but the complex redox chemistry of elements like sulphur is poorly simulated. The observed enrichment of many trace elements close to the redox fronts could be of significance for high-level waste repositories, but cannot be quantified by existing models. (author) 6 figs., 1 tab

Cold Fronts Research Programme: Progress, Future Plans, and Research Directions.

Science.gov (United States)

Ryan, B. F.; Wilson, K. J.; Garratt, J. R.; Smith, R. K.

1985-09-01

Following the analysis of data collected during Phases land II of the Cold Fronts Research Programme (CFRP) a conceptual model for the Australian summertime "cool change" has been proposed. The model provides a focus and a framework for the design of Phase III.The model is based on data gathered from a mesoscale network centered on Mount Gambier, South Australia, and includes the coastal waters to the west and relatively flat terrain to the east. The first objective of Phase III is to generalize the model so that it is applicable to the ocean waters to the far west of Mount Gambier and to the more rugged terrain farther to the east in the vicinity of Melbourne, Victoria. The remaining objectives concentrate on resolving unsatisfactory aspects of the model such as the evolution of convective lines and the relationship between the surface cold front and the upper-tropospheric cold pool and its associated jet stream.The integrated nature of the Cold Fronts Research Programme has meant that it has stimulated a wide range of research activities that extend beyond the field observations. The associated investigations include climatological, theoretical, and numerical modeling studies.

Pixel front-end development in 65 nm CMOS technology

International Nuclear Information System (INIS)

Havránek, M; Hemperek, T; Kishishita, T; Krüger, H; Wermes, N

2014-01-01

Luminosity upgrade of the LHC (HL-LHC) imposes severe constraints on the detector tracking systems in terms of radiation hardness and capability to cope with higher hit rates. One possible way of keeping track with increasing luminosity is the usage of more advanced technologies. Ultra deep sub-micron CMOS technologies allow a design of complex and high speed electronics with high integration density. In addition, these technologies are inherently radiation hard. We present a prototype of analog pixel front-end integrated circuit designed in 65 nm CMOS technology with applications oriented towards the ATLAS Pixel Detector upgrade. The aspects of ultra deep sub-micron design and performance of the analog pixel front-end circuits will be discussed

Ocean warming ameliorates the negative effects of ocean acidification on Paracentrotus lividus larval development and settlement.

Science.gov (United States)

García, Eliseba; Clemente, Sabrina; Hernández, José Carlos

2015-09-01

Ocean warming and acidification both impact marine ecosystems. All organisms have a limited body temperature range, outside of which they become functionally constrained. Beyond the absolute extremes of this range, they cannot survive. It is hypothesized that some stressors can present effects that interact with other environmental variables, such as ocean acidification (OA) that have the potential to narrow the thermal range where marine species are functional. An organism's response to ocean acidification can therefore be highly dependent on thermal conditions. This study evaluated the combined effects of predicted ocean warming conditions and acidification, on survival, development, and settlement, of the sea urchin Paracentrotus lividus. Nine combined treatments of temperature (19.0, 20.5 and 22.5 °C) and pH (8.1, 7.7 and 7.4 units) were carried out. All of the conditions tested were either within the current natural ranges of seawater pH and temperature or are within the ranges that have been predicted for the end of the century, in the sampling region (Canary Islands). Our results indicated that the negative effects of low pH on P. lividus larval development and settlement will be mitigated by a rise in seawater temperature, up to a thermotolerance threshold. Larval development and settlement performance of the sea urchin P. lividus was enhanced by a slight increase in temperature, even under lowered pH conditions. However, the species did show negative responses to the levels of ocean warming and acidification that have been predicted for the turn of the century. Copyright © 2015 Elsevier Ltd. All rights reserved.

Towards a regional ocean forecasting system for the IBI (Iberia-Biscay-Ireland area: developments and improvements within the ECOOP project framework

Directory of Open Access Journals (Sweden)

S. Cailleau

2012-03-01

Full Text Available The regional ocean operational system remains a key element in downscaling from large scale (global or basin scale systems to coastal ones. It enables the transition between systems in which the resolution and the resolved physics are quite different. Indeed, coastal applications need a system to predict local high frequency events (inferior to the day such as storm surges, while deep sea applications need a system to predict large scale lower frequency ocean features. In the framework of the ECOOP project, a regional system for the Iberia-Biscay-Ireland area has been upgraded from an existing V0 version to a V2. This paper focuses on the improvements from the V1 system, for which the physics are close to a large scale basin system, to the V2 for which the physics are more adapted to shelf and coastal issues. Strong developments such as higher regional physics resolution in the NEMO Ocean General Circulation Model for tides, non linear free surface and adapted vertical mixing schemes among others have been implemented in the V2 version. Thus, regional thermal fronts due to tidal mixing now appear in the latest version solution and are quite well positioned. Moreover, simulation of the stratification in shelf areas is also improved in the V2.

Ocean Research Enabled by Underwater Gliders.

Science.gov (United States)

Rudnick, Daniel L

2016-01-01

Underwater gliders are autonomous underwater vehicles that profile vertically by changing their buoyancy and use wings to move horizontally. Gliders are useful for sustained observation at relatively fine horizontal scales, especially to connect the coastal and open ocean. In this review, research topics are grouped by time and length scales. Large-scale topics addressed include the eastern and western boundary currents and the regional effects of climate variability. The accessibility of horizontal length scales of order 1 km allows investigation of mesoscale and submesoscale features such as fronts and eddies. Because the submesoscales dominate vertical fluxes in the ocean, gliders have found application in studies of biogeochemical processes. At the finest scales, gliders have been used to measure internal waves and turbulent dissipation. The review summarizes gliders' achievements to date and assesses their future in ocean observation.

Influence Of Tools Input/Output Requirements On Managers Core Front End Activities In New Product Development

DEFF Research Database (Denmark)

Appio, Francesco P.; Achiche, Sofiane; Minin, Alberto Di

2011-01-01

opportunities; make this early phase of the innovation process uncertain and extremely risky. Literature suggests that the understanding, selection and use of appropriate tools/techniques to support decision making are instrumental for a less fuzzy front end of innovation. This paper considers the adoption......The object of analysis of this explorative research is the Fuzzy Front End of Innovation in Product Development, described by those activities going from the opportunity identification to the concept definition. Business scholars have shown that confusion in terms of goals and different ideas about...

Development of combined brake system on front and rear brakes for scooter; Scooter yo zenkorin rendo brake system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Okazaki, Y; Itabashi, T; Shinohara, S; Honda, Y [Honda R and D Co. Ltd., Tokyo (Japan)

1997-10-01

Scooters need appropriate front and rear wheel braking power distribution and each of front and rear brakes have been operated using right and left levers. This time, a low cost brakes with cable type combined brake system for small size scooter and a brakes with hydraulic type combined brake system for middle size scooter have been developed to obtain appropriate front and rear wheel braking power distribution. Both systems use convenient left lever to operate. 3 refs., 9 figs., 1 tab.

The morphostructure of the atlantic ocean floor its development in the meso-cenozoic

CERN Document Server

Litvin, V M

1984-01-01

The study of the topography and structure of the ocean floor is one of the most important stages in ascertaining the geological structure and history of development of the Earth's oceanic crust. This, in its turn, provides a means for purposeful, scientifically-substantiated prospecting, exploration and development of the mineral resources of the ocean. The Atlantic Ocean has been geologically and geophysically studied to a great extent and many years of investigating its floor have revealed the laws governing the structure of the major forms of its submarine relief (e. g. , the continental shelf, the continental slope, the transition zones, the ocean bed, and the Mid-Oceanic Ridge). The basic features of the Earth's oceanic crust structure, anomalous geophysical fields, and the thickness and structure of its sedimentary cover have also been studied. Based on the investigations of the Atlantic Ocean floor and its surrounding continents, the presently prevalent concept of new global tectonics has appeared. A g...

The Western Barents Sea: where is the Caledonian Deformation Front?

Science.gov (United States)

Shulgin, Alexey; Aarseth, Iselin; Faleide, Jan Inge; Mjelde, Rolf; Huismans, Ritske

2017-04-01

The basement architecture below the Paleozoic sedimentary basins is still not fully understood in the Western Barents Sea region. It has been proposed that the early Devonian Caledonian orogeny has formed structural framework over which major basins have developed lately. However, the geometry of the Caledonian suture zone (its location, orientation and the extent of the deformation front) is still poorly constrained and is ambiguous in the Barents Sea. The crustal evolution of the Barents Sea and the basin-basement interaction is heavily dependent on the spatial extent and orientation of the Caledonian Deformation Front (CDF). In 2014 an active marine seismic experiment was conducted in the Western Barents Sea. One of the goals of the experiment is to discriminate between two existing models for orientations of the CDF: north-south from the potential fields data, and southwest-northeast from seismic data. We also aim to constrain the location of the CDF offshore northern Norway. We present the joint interpretation of collocated newly collected wide-angle seismic data (Ocean Bottom Seismometers) and reprocessing of the reflection seismic dataset (Multi-channel seismics) collected in the mid 1980's, using modern computational techniques. The two seismic methods provide best resolution at different depth ranges, and in our modeling we combine the results from the two methods to constrain the location of the CDF along transect running Northwest-Southeast across the Western Barents Sea.

Gust-Front and Outflow Related Waterspouts: Timely Warnings, Formation, and Impact on Public Safety

Science.gov (United States)

Cappucci, M.

2013-12-01

this vortex is likely caused by friction between the cooler air subducting behind the gust front against the warmer air ahead of the front. The vortex, on occasion, may be tilted onto a vertical axis by the warmer air ahead of the front; this same warm air now infiltrates the vertically-oriented vortex, thus being stretched, and forming a small waterspout. Because the waterspouts, however, are under the influence of the cool air from the thunderstorm downdraft, the spouts may move erratically before being upended. Because of the inability for NWS (National Weather Service) radar domes to detect the microscale circulation associated with such gust-front related waterspouts, forecasters at NWS offices in Massachusetts will now focus on the predecessors of waterspout formation. Among these tell-tale parameters is a well-pronounced gust-front moving over warm ocean waters, as well as a sharp, highly localized temperature contrast between the air ahead of and behind the gust front. When the NWS believes that conditions will favor the development of gust-front related waterspouts that may move onshore, a special statement will now be broadcast through the EAS system in Severe Thunderstorm Warnings. Mariners will benefit as well, with Special Marine Warnings advising caution on ';short-lived waterspouts'. Despite these alterations in NWS offices in Massachusetts, much has yet to be done to warn the public of the dangers associated with gust-front related waterspouts.

Development of a multi-channel front-end electronics module based on ASIC for silicon strip array detectors

International Nuclear Information System (INIS)

Zhao Xingwen; Yan Duo; Su Hong; Qian Yi; Kong Jie; Zhang Xueheng; Li Zhankui; Li Haixia

2014-01-01

The silicon strip array detector is one of external target facility subsystems in the Cooling Storage Ring on the Heavy Ion Research Facility at Lanzhou (HIRFL-CSR). Using the ASICs, the front-end electronics module has been developed for the silicon strip array detectors and can implement measurement of energy of 96 channels. The performance of the front-end electronics module has been tested. The energy linearity of the front-end electronics module is better than 0.3% for the dynamic range of 0.1∼0.7 V. The energy resolution is better than 0.45%. The maximum channel crosstalk is better than 10%. The channel consistency is better than 1.3%. After continuously working for 24 h at room temperature, the maximum drift of the zero-peak is 1.48 mV. (authors)

Ecosystem responses to biogeochemical fronts in the South Brazil Bight

Science.gov (United States)

Brandini, Frederico P.; Tura, Pedro M.; Santos, Pedro P. G. M.

2018-05-01

Here we described the general hydrography in the South Brazil Bight (23-28°S) with emphasis on frontal processes and their role in the structure and functioning of the regional shelf ecosystem. One of the key roles of fronts for ecosystem dynamics is the injection of nutrients into the euphotic zone increasing primary production. Frontal systems also affect plankton biodiversity and fisheries. Physical mechanisms behind frontogenesis in this region are similar in the analogous western side of oceanic basins; their magnitude and seasonal dynamics, however, may differ due to peculiarities in shelf morphology, wind field, tidal circulation and continental drainage. Here we provide a reassessment of earlier and recent ecological and hydrographic studies for a better evaluation of the spatial and temporal dynamics of fronts and their regional ecological implications. Albeit in a fragmented manner, we give a more detailed conceptual framework about the ecosystem responses to the complex frontal system in the South Brazil Bight.

Inclusion of the ocean breeze in Oyster Creek emergency off-site dose assessment

International Nuclear Information System (INIS)

Heck, W.

1986-01-01

The Oyster Creek Nuclear Generating Station (OCNGS) is located 6 mi west of the Atlantic Ocean. From spring through late summer, atmospheric transport in the vicinity of OCNGS is periodically affected by the ocean breeze. The ocean breeze produces large differences in wind direction within the OCNGS emergency planning zone during the morning to evening hours. In addition, trajectory reversals can occur near the ocean breeze front. These two characteristics of the ocean breeze must be taken into account when interpreting results from conventional atmospheric dispersion models. The purpose of the study was to determine the flow characteristics of the ocean breeze and to apply these characteristics to an emergency preparedness implementing procedure (EPIP). The EPIP would be used to determine the radiological plume impact region if an accidental release occurred during an ocean breeze

Ocean OSSEs: recent developments and future challenges

Science.gov (United States)

Kourafalou, V. H.

2012-12-01

Atmospheric OSSEs have had a much longer history of applications than OSSEs (and OSEs) in oceanography. Long standing challenges include the presence of coastlines and steep bathymetric changes, which require the superposition of a wide variety of space and time scales, leading to difficulties on ocean observation and prediction. For instance, remote sensing is critical for providing a quasi-synoptic oceanographic view, but the coverage is limited at the ocean surface. Conversely, in situ measurements are capable to monitor the entire water column, but at a single location and usually for a specific, short time. Despite these challenges, substantial progress has been made in recent years and international initiatives have provided successful OSSE/OSE examples and formed appropriate forums that helped define the future roadmap. These will be discussed, together with various challenges that require a community effort. Examples include: integrated (remote and in situ) observing system requirements for monitoring large scale and climatic changes, vs. short term variability that is particularly important on the regional and coastal spatial scales; satisfying the needs of both global and regional/coastal nature runs, from development to rigorous evaluation and under a clear definition of metrics; data assimilation in the presence of tides; estimation of real-time river discharges for Earth system modeling. An overview of oceanographic efforts that complement the standard OSSE methodology will also be given. These include ocean array design methods, such as representer-based analysis and adaptive sampling. Exciting new opportunities for both global and regional ocean OSSE/OSE studies have recently become possible with targeted periods of comprehensive data sets, such as the existing Gulf of Mexico observations from multiple sources in the aftermath of the DeepWater Horizon incident and the upcoming airborne AirSWOT, in preparation for the SWOT (Surface Water and Ocean

Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish.

Science.gov (United States)

Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A; Todgham, Anne E

2015-01-01

Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean warming interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 months). Using an integrative, experimental approach, our research examined the impacts of near-future warming [-1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined warming and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean warming and may experience negative physiological effects of ocean acidification only in

Observing the seasonal cycle of the upper ocean in the Ross Sea, Antarctica, with autonomous profiling floats

Science.gov (United States)

Porter, D. F.; Springer, S. R.; Padman, L.; Fricker, H. A.; Bell, R. E.

2017-12-01

The upper layers of the Southern Ocean where it meets the Antarctic ice sheet undergoes a large seasonal cycle controlled by surface radiation and by freshwater fluxes, both of which are strongly influenced by sea ice. In regions where seasonal sea ice and icebergs limit use of ice-tethered profilers and conventional moorings, autonomous profiling floats can sample the upper ocean. The deployment of seven Apex floats (by sea) and six ALAMO floats (by air) provides unique upper ocean hydrographic data in the Ross Sea close to the Ross Ice Shelf front. A novel choice of mission parameters - setting parking depth deeper than the seabed - limits their drift, allowing us to deploy the floats close to the ice shelf front, while sea ice avoidance algorithms allow the floats to to sample through winter under sea ice. Hydrographic profiles show the detailed development of the seasonal mixed layer close to the Ross front, and interannual variability of the seasonal mixed layer and deeper water masses on the central Ross Sea continental shelf. After the sea ice breakup in spring, a warm and fresh surface mixed layer develops, further warming and deepening throughout the summer. The mixed layer deepens, with maximum temperatures exceeding 0ºC in mid-February. By March, the surface energy budget becomes negative and sea ice begins to form, creating a cold, saline and dense surface layer. Once these processes overcome the stable summer stratification, convection erodes the surface mixed layer, mixing some heat downwards to deeper layers. There is considerable interannual variability in the evolution and strength of the surface mixed layer: summers with shorter ice-free periods result in a cooler and shallower surface mixed layer, which accumulates less heat than the summers with longer ice-free periods. Early ice breakup occurred in all floats in 2016/17 summer, enhancing the absorbed solar flux leading to a warmer surface mixed layer. Together, these unique measurements from

Impact of ocean model resolution on CCSM climate simulations

Energy Technology Data Exchange (ETDEWEB)

Kirtman, Ben P.; Rousset, Clement; Siqueira, Leo [University of Miami, Rosenstiel School for Marine and Atmospheric Science, Coral Gables, FL (United States); Bitz, Cecilia [University of Washington, Department of Atmospheric Science, Seattle, WA (United States); Bryan, Frank; Dennis, John; Hearn, Nathan; Loft, Richard; Tomas, Robert; Vertenstein, Mariana [National Center for Atmospheric Research, Boulder, CO (United States); Collins, William [University of California, Berkeley, Berkeley, CA (United States); Kinter, James L.; Stan, Cristiana [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); George Mason University, Fairfax, VA (United States)

2012-09-15

The current literature provides compelling evidence suggesting that an eddy-resolving (as opposed to eddy-permitting or eddy-parameterized) ocean component model will significantly impact the simulation of the large-scale climate, although this has not been fully tested to date in multi-decadal global coupled climate simulations. The purpose of this paper is to examine how resolved ocean fronts and eddies impact the simulation of large-scale climate. The model used for this study is the NCAR Community Climate System Model version 3.5 (CCSM3.5) - the forerunner to CCSM4. Two experiments are reported here. The control experiment is a 155-year present-day climate simulation using a 0.5 atmosphere component (zonal resolution 0.625 meridional resolution 0.5 ; land surface component at the same resolution) coupled to ocean and sea-ice components with zonal resolution of 1.2 and meridional resolution varying from 0.27 at the equator to 0.54 in the mid-latitudes. The second simulation uses the same atmospheric and land-surface models coupled to eddy-resolving 0.1 ocean and sea-ice component models. The simulations are compared in terms of how the representation of smaller scale features in the time mean ocean circulation and ocean eddies impact the mean and variable climate. In terms of the global mean surface temperature, the enhanced ocean resolution leads to a ubiquitous surface warming with a global mean surface temperature increase of about 0.2 C relative to the control. The warming is largest in the Arctic and regions of strong ocean fronts and ocean eddy activity (i.e., Southern Ocean, western boundary currents). The Arctic warming is associated with significant losses of sea-ice in the high-resolution simulation. The sea surface temperature gradients in the North Atlantic, in particular, are better resolved in the high-resolution model leading to significantly sharper temperature gradients and associated large-scale shifts in the rainfall. In the extra-tropics, the

Southern Ocean Carbon Dioxide and Oxygen Fluxes Detected by SOCCOM Biogeochemical Profiling Floats

Science.gov (United States)

Sarmiento, J. L.; Bushinksy, S.; Gray, A. R.

2016-12-01

The Southern Ocean is known to play an important role in the global carbon cycle, yet historically our measurements of this remote region have been sparse and heavily biased towards summer. Here we present new estimates of air-sea fluxes of carbon dioxide and oxygen calculated with measurements from autonomous biogeochemical profiling floats. At high latitudes in and southward of the Antarctic Circumpolar Current, we find a significant flux of CO2 from the ocean to the atmosphere during 2014-2016, which is particularly enhanced during winter months. These results suggest that previous estimates may be biased towards stronger Southern Ocean CO2 uptake due to undersampling in winter. We examine various implications of having a source of CO2 that is higher than previous estimates. We also find that CO2:O2 flux ratios north of the Subtropical Front are positive, consistent with the fluxes being driven by changes in solubility, while south of the Polar Front biological processes and upwelling of deep water combine to produce a negative CO2:O2 flux ratio.

Spatially hybrid computations for streamer discharges with generic features of pulled fronts: I. Planar fronts

International Nuclear Information System (INIS)

Li Chao; Ebert, Ute; Hundsdorfer, Willem

2010-01-01

Streamers are the first stage of sparks and lightning; they grow due to a strongly enhanced electric field at their tips; this field is created by a thin curved space charge layer. These multiple scales are already challenging when the electrons are approximated by densities. However, electron density fluctuations in the leading edge of the front and non-thermal stretched tails of the electron energy distribution (as a cause of X-ray emissions) require a particle model to follow the electron motion. But present computers cannot deal with all electrons in a fully developed streamer. Therefore, super-particle have to be introduced, which leads to wrong statistics and numerical artifacts. The method of choice is a hybrid computation in space where individual electrons are followed in the region of high electric field and low density while the bulk of the electrons is approximated by densities (or fluids). We here develop the hybrid coupling for planar fronts. First, to obtain a consistent flux at the interface between particle and fluid model in the hybrid computation, the widely used classical fluid model is replaced by an extended fluid model. Then the coupling algorithm and the numerical implementation of the spatially hybrid model are presented in detail, in particular, the position of the model interface and the construction of the buffer region. The method carries generic features of pulled fronts that can be applied to similar problems like large deviations in the leading edge of population fronts, etc.

Cold Front Driven Flows Through Multiple Inlets of Lake Pontchartrain Estuary

Science.gov (United States)

Huang, Wei; Li, Chunyan

2017-11-01

With in situ observations using acoustic Doppler current profilers (ADCPs) and numerical experiments using the Finite Volume Coastal Ocean Model (FVCOM), this study investigates atmospheric cold front induced exchange of water between Lake Pontchartrain Estuary and coastal ocean through multiple inlets. Results show that the subtidal hydrodynamic response is highly correlated with meteorological parameters. Northerly and westerly winds tend to push water out of Lake Pontchartrain, while south and east winds tend to produce currents flowing into it. For most cases, the subtidal water level is inversely correlated with the east wind, with the correlation coefficient being ˜0.8. The most important finding of this work is that, contrary to intuition, the cold front induced remote wind effect has the greatest contribution to the overall water level variation, while the local wind stress determines the surface slope inside the estuary. It is found that wind driven flow is roughly quasi steady state: the surface slope in the north-south direction is determined by the north-south wind stress, explaining ˜83% of the variability but less so in the east-west direction (˜43%). In other words, the north-south local wind stress determines the water level gradient in that direction in the estuary while the overall water level change is pretty much controlled by the open boundary which is the "remote wind effect," a regional response that can be illustrated only by a numerical model for a much larger area encompassing the estuary.

Development of the North Pacific Ocean model for the assessment of the distribution of the radioactive materials. Improvement for formation of the North Pacific intermediate water

International Nuclear Information System (INIS)

Tsubono, Takaki; Misumi, Kazuhiro; Tsumune, Daisuke; Bryan, Frank

2014-01-01

The radioactive materials such as 137 Cs were released to the North Pacific Ocean (NP) through the major pathway; direct release from the accident site and atmospheric deposition, after the accidents at the Fukushima Dai-ichi Nuclear Power Plant following the earthquake and tsunami. The behavior of the materials in the NP has been paid great attention after the accident. The North Pacific Model for the calculation of the distribution of radionuclides has been developed using Regional Ocean Modeling System (ROMS). The model domain is NP with an eddy-resolving grid. A series of numerical experiments conducted by models suggests that the computational diffusivity caused by the advection scheme and the topography roughness are critical in representing the separation of Kuroshio, the Kuroshio Extension, the mixed-water region between Kuroshio Extension and Oyashio front and the formation of the North Pacific Intermediate Water (NPIW). The model requires the forth order scheme in the tracer advection and the smoothing of topography for these problems. Moreover the tidal mixing process around the straits in the North Pacific Ocean and the sea ice play important roles to reproduce the formation of lon salinity around the NPIW as well as the isopycnal mixing process represented by an eddy-resolving model. (author)

Negative Ion Density Fronts

International Nuclear Information System (INIS)

Igor Kaganovich

2000-01-01

Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

Simulating calving-front changes of Greenland’s marine-terminating glaciers

DEFF Research Database (Denmark)

Haubner, Konstanze

glacier retreat to a certain degree and foremost define the variation of retreat rates. The thesis implies the importance of incorporating glacier-front dynamics into ice sheet models in order to match observations and verifies atmospheric and oceanic forcing as important triggers for glacier retreat...... UI outlet glaciers. The change in mass flux resulting from the prescribed glacier retreat contributes to 70% of UI’s mass change over the simulation periods. The residual mass change is due to surface mass balance. A second simulation on the fastest UI glacier (UI-1) reveals that frontal melt rates...

On Front Slope Stability of Berm Breakwaters

DEFF Research Database (Denmark)

Burcharth, Hans F.

2013-01-01

The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison...... with the reshaping of a large Norwegian breakwater exposed to the North Sea waves. As a motivation for applying the Van der Meer formula a discussion of design parameters related to berm breakwater stability formulae is given. Comparisons of front erosion predicted by the use of the Van der Meer formula with model...... test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height...

Observational Analysis of Cloud and Precipitation in Midlatitude Cyclones: Northern Versus Southern Hemisphere Warm Fronts

Science.gov (United States)

Naud, Catherine M.; Posselt, Derek J.; van den Heever, Susan C.

2012-01-01

Extratropical cyclones are responsible for most of the precipitation and wind damage in the midlatitudes during the cold season, but there are still uncertainties on how they will change in a warming climate. An ubiquitous problem amongst General Circulation Models (GCMs) is a lack of cloudiness over the southern oceans that may be in part caused by a lack of clouds in cyclones. We analyze CloudSat, CALIPSO and AMSR-E observations for 3 austral and boreal cold seasons and composite cloud frequency of occurrence and precipitation at the warm fronts for northern and southern hemisphere oceanic cyclones. We find that cloud frequency of occurrence and precipitation rate are similar in the early stage of the cyclone life cycle in both northern and southern hemispheres. As cyclones evolve and reach their mature stage, cloudiness and precipitation at the warm front increase in the northern hemisphere but decrease in the southern hemisphere. This is partly caused by lower amounts of precipitable water being available to southern hemisphere cyclones, and smaller increases in wind speed as the cyclones evolve. Southern hemisphere cloud occurrence at the warm front is found to be more sensitive to the amount of moisture in the warm sector than to wind speeds. This suggests that cloudiness in southern hemisphere storms may be more susceptible to changes in atmospheric water vapor content, and thus to changes in surface temperature than their northern hemisphere counterparts. These differences between northern and southern hemisphere cyclones are statistically robust, indicating A-Train-based analyses as useful tools for evaluation of GCMs in the next IPCC report.

The roles of different mechanisms related to the tide-induced fronts in the Yellow Sea in summer

Science.gov (United States)

Ren, Shihe; Xie, Jiping; Zhu, Jiang

2014-09-01

In summer, the Yellow Sea Cold Water Mass (YSCWM) is a stable water mass of low temperature lying at the bottom of the central Yellow Sea (YS). It is fringed by some typical tidal fronts, which separate deep, stratified water on the offshore side from the well-mixed, shallow water on the inshore side. Three striking fronts—Subei Bank Front (SBF), Shandong Peninsula Front (SPF), and Mokpo Front (MKF; a front off the southwestern tip of the Korean Peninsula)—have been identified by various studies from both satellite observations and model results. Tide plays an important role in the formation and maintenance of these fronts. However, it is still a matter of debate as to the roles these two kinds of mechanisms of upwelling and tidal mixing play, and how importance they are in the maintenance processes of the above three fronts. Basing a nested high-resolution model HYCOM (the Hybrid Coordinate Ocean Model), this study focuses on the different mechanisms of tidal effects on the thermal fronts in the YS in summertime. Through comparative experiments with and without tidal forcing, the results indicate that the MKF is mainly driven by tide-induced upwelling. For the SPF, tidal mixing is the dominant factor, when lower cold water is stirred upwards along the sloping topography of the western YS. Meanwhile, the combined effect of upwelling and tidal mixing is the main cause of the formation of the SBF. Diagnostic analysis of thermal balance shows that horizontal nonlinear advection induced by strong tidal currents also contributes to the thermal balance of frontal areas.

Lagrangian analysis of multi-satellite data in support of open ocean Marine Protected Area design

Science.gov (United States)

Della Penna, Alice; Koubbi, Philippe; Cotté, Cedric; Bon, Cécile; Bost, Charles-André; d'Ovidio, Francesco

2017-06-01

Compared to ecosystem conservation in territorial seas, protecting the open ocean has peculiar geopolitical, economic and scientific challenges. One of the major obstacle is defining the boundary of an open ocean Marine Protected Area (MPA). In contrast to coastal ecosystems, which are mostly constrained by topographic structures fixed in time, the life of marine organisms in the open ocean is entrained by fluid dynamical structures like eddies and fronts, whose lifetime occurs on ecologically-relevant timescales. The position of these highly dynamical structures can vary interannually by hundreds of km, and so too will regions identified as ecologically relevant such as the foraging areas of marine predators. Thus, the expected foraging locations suggested from tracking data cannot be directly extrapolated beyond the year in which the data were collected. Here we explore the potential of Lagrangian methods applied to multisatellite data as a support tool for a MPA proposal by focusing on the Crozet archipelago oceanic area (Indian Sector of the Southern Ocean). By combining remote sensing with biologging information from a key marine top predator (Eudyptes chrysolophus, or Macaroni penguin) of the Southern Ocean foodweb, we identify a highly dynamic branch of the Subantarctic front as a foraging hotspot. By tracking this feature in historical satellite data (1993-2012) we are able to extrapolate the position of this foraging ground beyond the years in which tracking data are available and study its spatial variability.

Modelling larval transport in a axial convergence front

Science.gov (United States)

Robins, P.

2010-12-01

Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

OpenAIRE

Chauché , N.; Hubbard , A.; Gascard , Jean-Claude; Box , J. E.; Bates , R.; Koppes , M.; Sole , A.; Christoffersen , P.; Patton , H.

2014-01-01

International audience; Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estim...

Light-Front Holography, Light-Front Wavefunctions, and Novel QCD Phenomena

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.

2012-02-16

Light-Front Holography is one of the most remarkable features of the AdS/CFT correspondence. In spite of its present limitations it provides important physical insights into the nonperturbative regime of QCD and its transition to the perturbative domain. This novel framework allows hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The model leads to an effective confining light-front QCD Hamiltonian and a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound-state wavefunctions, and thus the fall-off as a function of the invariant mass of the constituents. The soft-wall holographic model modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics - a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryons. The model predicts a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number n. The hadron eigensolutions projected on the free Fock basis provides the complete set of valence and non-valence light-front Fock state wavefunctions {Psi}{sub n/H} (x{sub i}, k{sub {perpendicular}i}, {lambda}{sub i}) which describe the hadron's momentum and spin distributions needed to compute the direct measures of hadron structure at the quark and gluon level, such as elastic and transition form factors, distribution amplitudes, structure functions, generalized parton distributions and transverse

Fuzzy decision support for tools selection in the core front end activities of new product development

NARCIS (Netherlands)

Achiche, S.; Appio, F.; McAloone, T.; Di Minin, Alberto

2012-01-01

The innovation process may be divided into three main parts: the front end (FE), the new product development (NPD) process, and the commercialization. Every NPD process has a FE in which products and projects are defined. However, companies tend to begin the stages of FE without a clear definition

Climate Ocean Modeling on a Beowulf Class System

Science.gov (United States)

Cheng, B. N.; Chao, Y.; Wang, P.; Bondarenko, M.

2000-01-01

With the growing power and shrinking cost of personal computers. the availability of fast ethernet interconnections, and public domain software packages, it is now possible to combine them to build desktop parallel computers (named Beowulf or PC clusters) at a fraction of what it would cost to buy systems of comparable power front supercomputer companies. This led as to build and assemble our own sys tem. specifically for climate ocean modeling. In this article, we present our experience with such a system, discuss its network performance, and provide some performance comparison data with both HP SPP2000 and Cray T3E for an ocean Model used in present-day oceanographic research.

Oceanic fronts in the Sargasso Sea control the early life and drift of Atlantic eels

DEFF Research Database (Denmark)

Munk, Peter; Hansen, Michael Møller; Maas, Gregory E.

2010-01-01

Anguillid freshwater eels show remarkable life histories. In the Atlantic, the European eel (Anguilla anguilla) and American eel (Anguilla rostrata) undertake extensive migrations to spawn in the oceanic Sargasso Sea, and subsequently the offspring drift to foraging areas in Europe and North......, during a field expedition to the eel spawning sites in the Sargasso Sea, we carried out a wide range of dedicated bio-physical studies across areas of eel larval distribution. Our findings suggest a key role of oceanic frontal processes, retaining eel larvae within a zone of enhanced feeding conditions...

Statistical Physics and Light-Front Quantization

Energy Technology Data Exchange (ETDEWEB)

Raufeisen, J

2004-08-12

Light-front quantization has important advantages for describing relativistic statistical systems, particularly systems for which boost invariance is essential, such as the fireball created in a heavy ion collisions. In this paper the authors develop light-front field theory at finite temperature and density with special attention to quantum chromodynamics. They construct the most general form of the statistical operator allowed by the Poincare algebra and show that there are no zero-mode related problems when describing phase transitions. They then demonstrate a direct connection between densities in light-front thermal field theory and the parton distributions measured in hard scattering experiments. The approach thus generalizes the concept of a parton distribution to finite temperature. In light-front quantization, the gauge-invariant Green's functions of a quark in a medium can be defined in terms of just 2-component spinors and have a much simpler spinor structure than the equal-time fermion propagator. From the Green's function, the authors introduce the new concept of a light-front density matrix, whose matrix elements are related to forward and to off-diagonal parton distributions. Furthermore, they explain how thermodynamic quantities can be calculated in discretized light-cone quantization, which is applicable at high chemical potential and is not plagued by the fermion-doubling problems.

Developing a Front-of-Package Labelling System in Guatemala to ...

International Development Research Centre (IDRC) Digital Library (Canada)

With one of the highest per capita consumption rates of soft drinks globally, the people ... a front-of-package label on energy-dense, nutrient-poor foods and beverages to ... New labels for sugar-sweetened beverages This research will target ...

Modeling the response of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge

Science.gov (United States)

Morlighem, M.; Wood, M.; Seroussi, H. L.; Bondzio, J. H.; Rignot, E. J.

2017-12-01

Glacier-front dynamics is an important control on Greenland's ice mass balance. Warm and salty Atlantic water, which is typically found at a depth below 200-300 m, has the potential to trigger ice-front retreats of marine-terminating glaciers, and the corresponding loss in resistive stress leads to glacier acceleration and thinning. It remains unclear, however, which glaciers are currently stable but may retreat in the future, and how far inland and how fast they will retreat. Here, we quantify the sensitivity and vulnerability of marine-terminating glaciers along the Northwest coast of Greenland (from 72.5° to 76°N) to ocean forcing using the Ice Sheet System Model (ISSM), and its new ice front migration capability. We rely on the ice melt parameterization from Rignot et al. 2016, and use ocean temperature and salinity from high-resolution ECCO2 simulations on the continental shelf to constrain the thermal forcing. The ice flow model includes a calving law based on a Von Mises criterion. We investigate the sensitivity of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge. We find that some glaciers, such as Dietrichson Gletscher or Alison Gletscher, are sensitive to small increases in ocean thermal forcing, while others, such as Illullip Sermia or Qeqertarsuup Sermia, are very difficult to destabilize, even with a quadrupling of the melt. Under the most intense melt experiment, we find that Hayes Gletscher retreats by more than 50 km inland into a deep trough and its velocity increases by a factor of 10 over only 15 years. The model confirms that ice-ocean interactions are the triggering mechanism of glacier retreat, but the bed controls its magnitude. This work was performed at the University of California Irvine under a contract with the National Aeronautics and Space Administration, Cryospheric Sciences Program (#NNX15AD55G), and the National Science Foundation's ARCSS program (#1504230).

Pole solutions for flame front propagation

CERN Document Server

Kupervasser, Oleg

2015-01-01

This book deals with solving mathematically the unsteady flame propagation equations. New original mathematical methods for solving complex non-linear equations and investigating their properties are presented. Pole solutions for flame front propagation are developed. Premixed flames and filtration combustion have remarkable properties: the complex nonlinear integro-differential equations for these problems have exact analytical solutions described by the motion of poles in a complex plane. Instead of complex equations, a finite set of ordinary differential equations is applied. These solutions help to investigate analytically and numerically properties of the flame front propagation equations.

An assessment of research and development leadership in ocean energy technologies

International Nuclear Information System (INIS)

Bruch, V.L.

1994-04-01

Japan is clearly the leader in ocean energy technologies. The United Kingdom also has had many ocean energy research projects, but unlike Japan, most of the British projects have not progressed from the feasibility study stage to the demonstration stage. Federally funded ocean energy research in the US was stopped because it was perceived the technologies could not compete with conventional sources of fuel. Despite the probable small market for ocean energy technologies, the short sighted viewpoint of the US government regarding funding of these technologies may be harmful to US economic competitiveness. The technologies may have important uses in other applications, such as offshore construction and oil and gas drilling. Discontinuing the research and development of these technologies may cause the US to lose knowledge and miss market opportunities. If the US wishes to maintain its knowledge base and a market presence for ocean energy technologies, it may wish to consider entering into a cooperative agreement with Japan and/or the United Kingdom. Cooperative agreements are beneficial not only for technology transfer but also for cost-sharing

Geochemistry of Natural Redox Fronts

International Nuclear Information System (INIS)

Hofmann, B.A.

1999-05-01

Redox fronts are important geochemical boundaries which need to be considered in safety assessment of deep repositories for radioactive waste. In most cases, selected host-rock formations will be reducing due to the presence of ferrous minerals, sulphides, etc. During construction and operation of the repository, air will be introduced into the formation. After repository closure, oxidising conditions may persist locally until all oxygen is consumed. In the case of high-level waste, radiolysis of water may provide an additional source of oxidants. Oxidising conditions within a repository are thus possible and potentially have a strong influence on the mobility of many elements. The rate of movement of redox fronts, the boundary between oxidising and reducing environments, and their influence on migrating radionuclides are thus important factors influencing repository performance. The present report is a review of elemental behaviour at natural redox fronts, based on published information and work of the author. Redox fronts are geochemically and geometrically variable manifestations of a global interface between generally oxidising geochemical milieux in contact with the atmosphere and generally reducing milieux in contact with rocks containing ferrous iron, sulphide and/or organic carbon. A classification of redox fronts based on a subdivision into continental near-surface, marine near-surface, and deep environments is proposed. The global redox interface is often located close to the surface of rocks and sediments and, sometimes, within bodies of water. Temperature conditions are close to ambient. A deeper penetration of the global redox front to depths of several kilometres is found in basins containing oxidised sediments (red beds) and in some hydrothermal circulation systems. Temperatures at such deep redox fronts may reach 200 o C. Both near-surface and deep redox fronts are sites of formation of economic deposits of redox-sensitive elements, particularly of

Oceanic emissions of sulfur: Application of new techniques

Science.gov (United States)

Jodwalis, Clara Mary

Sulfur gases and aerosols are important in the atmosphere because they play major roles in acid rain, arctic haze, air pollution, and climate. Globally, man-made and natural sulfur emissions are comparable in magnitude. The major natural source is dimethyl sulfide (DMS) from the oceans, where it originates from the degradation of dimethysulfonioproprionate (DMSP), a compound produced by marine phytoplankton. Global budgets of natural sulfur emissions are uncertain because of (1) the uncertainty in the traditional method used to estimate DMS sea-to-air flux, and (2) the spatial and temporal variability of DMS sea-to-air flux. We have worked to lessen the uncertainty on both fronts. The commonly used method for estimating DMS sea-to-air flux is certain to a factor of two, at best. We used a novel instrumental technique to measure, for the first time, sulfur gas concentration fluctuations in the marine boundary layer. The measured concentration fluctuations were then used with two established micrometeorological techniques to estimate sea-to-air flux of sulfur. Both methods appear to be more accurate than the commonly used one. The analytical instrument we used in our studies shows potential as a direct flux measurement device. High primary productivity in high-latitude oceans suggests a potentially large DMS source from northern oceans. To begin to investigate this hypothesis, we have measured DMS in the air over northern oceans around Alaska. For integrating and extrapolating field measurements over larger areas and longer time periods, we have developed a model of DMS ocean mixing, biological production, and sea-to-air flux of DMS. The model's main utility is in gaining intuition on which parameters are most important to DMS sea-to-air flux. This information, along with a direct flux measurement capability, are crucial steps toward the long-term goal of remotely sensing DMS flux. A remote sensing approach will mitigate the problems of spatial and temporal

Radiocarbon Content of Dissolved Organic Carbon in the South Indian Ocean

Science.gov (United States)

Bercovici, S. K.; McNichol, A. P.; Xu, L.; Hansell, D. A.

2018-01-01

We report four profiles of the radiocarbon content of dissolved organic carbon (DOC) spanning the South Indian Ocean (SIO), ranging from the Polar Front (56°S) to the subtropics (29°S). Surface waters held mean DOC Δ14C values of -426 ± 6‰ ( 4,400 14C years) at the Polar Front and DOC Δ14C values of -252 ± 22‰ ( 2,000 14C years) in the subtropics. At depth, Circumpolar Deep Waters held DOC Δ14C values of -491 ± 13‰ ( 5,400 years), while values in Indian Deep Water were more depleted, holding DOC Δ14C values of -503 ± 8‰ ( 5,600 14C years). High-salinity North Atlantic Deep Water intruding into the deep SIO had a distinctly less depleted DOC Δ14C value of -481 ± 8‰ ( 5,100 14C years). We use multiple linear regression to assess the dynamics of DOC Δ14C values in the deep Indian Ocean, finding that their distribution is characteristic of water masses in that region.

Numerical methods and inversion algorithms in reservoir simulation based on front tracking

Energy Technology Data Exchange (ETDEWEB)

Haugse, Vidar

1999-04-01

This thesis uses front tracking to analyse laboratory experiments on multiphase flow in porous media. New methods for parameter estimation for two- and three-phase relative permeability experiments have been developed. Up scaling of heterogeneous and stochastic porous media is analysed. Numerical methods based on front tracking is developed and analysed. Such methods are efficient for problems involving steep changes in the physical quantities. Multi-dimensional problems are solved by combining front tracking with dimensional splitting. A method for adaptive grid refinement is developed.

Pareto fronts in clinical practice for pinnacle.

Science.gov (United States)

Janssen, Tomas; van Kesteren, Zdenko; Franssen, Gijs; Damen, Eugène; van Vliet, Corine

2013-03-01

Our aim was to develop a framework to objectively perform treatment planning studies using Pareto fronts. The Pareto front represents all optimal possible tradeoffs among several conflicting criteria and is an ideal tool with which to study the possibilities of a given treatment technique. The framework should require minimal user interaction and should resemble and be applicable to daily clinical practice. To generate the Pareto fronts, we used the native scripting language of Pinnacle(3) (Philips Healthcare, Andover, MA). The framework generates thousands of plans automatically from which the Pareto front is generated. As an example, the framework is applied to compare intensity modulated radiation therapy (IMRT) with volumetric modulated arc therapy (VMAT) for prostate cancer patients. For each patient and each technique, 3000 plans are generated, resulting in a total of 60,000 plans. The comparison is based on 5-dimensional Pareto fronts. Generating 3000 plans for 10 patients in parallel requires on average 96 h for IMRT and 483 hours for VMAT. Using VMAT, compared to IMRT, the maximum dose of the boost PTV was reduced by 0.4 Gy (P=.074), the mean dose in the anal sphincter by 1.6 Gy (P=.055), the conformity index of the 95% isodose (CI(95%)) by 0.02 (P=.005), and the rectal wall V(65 Gy) by 1.1% (P=.008). We showed the feasibility of automatically generating Pareto fronts with Pinnacle(3). Pareto fronts provide a valuable tool for performing objective comparative treatment planning studies. We compared VMAT with IMRT in prostate patients and found VMAT had a dosimetric advantage over IMRT. Copyright © 2013 Elsevier Inc. All rights reserved.

Pareto Fronts in Clinical Practice for Pinnacle

International Nuclear Information System (INIS)

Janssen, Tomas; Kesteren, Zdenko van; Franssen, Gijs; Damen, Eugène; Vliet, Corine van

2013-01-01

Purpose: Our aim was to develop a framework to objectively perform treatment planning studies using Pareto fronts. The Pareto front represents all optimal possible tradeoffs among several conflicting criteria and is an ideal tool with which to study the possibilities of a given treatment technique. The framework should require minimal user interaction and should resemble and be applicable to daily clinical practice. Methods and Materials: To generate the Pareto fronts, we used the native scripting language of Pinnacle 3 (Philips Healthcare, Andover, MA). The framework generates thousands of plans automatically from which the Pareto front is generated. As an example, the framework is applied to compare intensity modulated radiation therapy (IMRT) with volumetric modulated arc therapy (VMAT) for prostate cancer patients. For each patient and each technique, 3000 plans are generated, resulting in a total of 60,000 plans. The comparison is based on 5-dimensional Pareto fronts. Results: Generating 3000 plans for 10 patients in parallel requires on average 96 h for IMRT and 483 hours for VMAT. Using VMAT, compared to IMRT, the maximum dose of the boost PTV was reduced by 0.4 Gy (P=.074), the mean dose in the anal sphincter by 1.6 Gy (P=.055), the conformity index of the 95% isodose (CI 95% ) by 0.02 (P=.005), and the rectal wall V 65 Gy by 1.1% (P=.008). Conclusions: We showed the feasibility of automatically generating Pareto fronts with Pinnacle 3 . Pareto fronts provide a valuable tool for performing objective comparative treatment planning studies. We compared VMAT with IMRT in prostate patients and found VMAT had a dosimetric advantage over IMRT

Front Propagation in Stochastic Neural Fields

KAUST Repository

Bressloff, Paul C.

2012-01-01

We analyze the effects of extrinsic multiplicative noise on front propagation in a scalar neural field with excitatory connections. Using a separation of time scales, we represent the fluctuating front in terms of a diffusive-like displacement (wandering) of the front from its uniformly translating position at long time scales, and fluctuations in the front profile around its instantaneous position at short time scales. One major result of our analysis is a comparison between freely propagating fronts and fronts locked to an externally moving stimulus. We show that the latter are much more robust to noise, since the stochastic wandering of the mean front profile is described by an Ornstein-Uhlenbeck process rather than a Wiener process, so that the variance in front position saturates in the long time limit rather than increasing linearly with time. Finally, we consider a stochastic neural field that supports a pulled front in the deterministic limit, and show that the wandering of such a front is now subdiffusive. © 2012 Society for Industrial and Applied Mathematics.

Development of ATLAS Liquid Argon Calorimeter Front-end Electronics for the HL-LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00219286; The ATLAS collaboration

2016-01-01

The high-luminosity phase of the Large Hadron Collider will provide 5-7 times greater luminosities than assumed in the original detector design. An improved trigger system requires an upgrade of the readout electronics of the ATLAS Liquid Argon Calorimeter. Concepts for the future readout of the 182,500 calorimeter channels at 40-80 MHz and 16-bit dynamic range and the developments of radiation-tolerant, low-noise, low-power, and high-bandwidth front-end electronic components, including preamplifiers and shapers, 14-bit ADCs, and 10-Gb/s laser diode array drivers, are presented.

Contrasting distributions of dissolved gaseous mercury concentration and evasion in the North Pacific Subarctic Gyre and the Subarctic Front

Science.gov (United States)

Kim, Hyunji; Rhee, Tae Siek; Hahm, Doshik; Hwang, Chung Yeon; Yang, Jisook; Han, Seunghee

2016-04-01

The distribution of dissolved gaseous mercury (DGM) and the oxidation-reduction processes of mercury (Hg) in the surface and subsurface ocean are currently understudied despite their importance in ocean-atmosphere interactions. We investigated the Hg(0) evasion and the DGM distribution at water depths of 2-500 m in the Subarctic Front, Western Subarctic Gyre, and Bering Sea of the Northwestern Pacific. The mean DGM concentration in the surface mixed water (evasion flux were significantly higher in the Subarctic Front (125±5.0 fM and 15 pmol m-2 h-1, respectively), which typically has lower nutrient levels and higher primary production, than in the Western Subarctic Gyre and the Bering Sea (74±18 fM and 3.2±1.2 pmol m-2 h-1, respectively). The variation in the chlorophyll-a concentration and extracellular protease activity predicted 54% and 48% of the DGM variation, respectively, in the euphotic zone (2-50 m). The DGM concentration in aphotic intermediate water (415±286 fM) was positively correlated to the apparent oxygen utilization (AOU; r2=0.94 and pevasion is closely linked to primary production in euphotic water and organic remineralization in aphotic intermediate water. The oceanic alterations in these factors may induce significant modification in Hg redox speciation in the Northwestern Pacific.

Light-Front QCD

Energy Technology Data Exchange (ETDEWEB)

Brodsky, S.

2004-11-30

In these lectures, I survey a number of applications of light-front methods to hadron and nuclear physics phenomenology and dynamics, including light-front statistical physics. Light-front Fock-state wavefunctions provide a frame-independent representation of hadrons in terms of their fundamental quark and gluon degrees of freedom. Nonperturbative methods for computing LFWFs in QCD are discussed, including string/gauge duality which predicts the power-law fall-off at high momentum transfer of light-front Fock-state hadronic wavefunctions with an arbitrary number of constituents and orbital angular momentum. The AdS/CFT correspondence has important implications for hadron phenomenology in the conformal limit, including an all-orders derivation of counting rules for exclusive processes. One can also compute the hadronic spectrum of near-conformal QCD assuming a truncated AdS/CFT space. Given the LFWFs, one can compute form factors, heavy hadron decay amplitudes, hadron distribution amplitudes, and the generalized parton distributions underlying deeply virtual Compton scattering. The quantum fluctuations represented by the light-front Fock expansion leads to novel QCD phenomena such as color transparency, intrinsic heavy quark distributions, diffractive dissociation, and hidden-color components of nuclear wavefunctions. A new test of hidden color in deuteron photodisintegration is proposed. The origin of leading-twist phenomena such as the diffractive component of deep inelastic scattering, single-spin asymmetries, nuclear shadowing and antishadowing is also discussed; these phenomena cannot be described by light-front wavefunctions of the target computed in isolation. Part of the anomalous NuTeV results for the weak mixing angle {theta}{sub W} could be due to the non-universality of nuclear antishadowing for charged and neutral currents.

Slow science: the value of long ocean biogeochemistry records.

Science.gov (United States)

Henson, Stephanie A

2014-09-28

Sustained observations (SOs) have provided invaluable information on the ocean's biology and biogeochemistry for over 50 years. They continue to play a vital role in elucidating the functioning of the marine ecosystem, particularly in the light of ongoing climate change. Repeated, consistent observations have provided the opportunity to resolve temporal and/or spatial variability in ocean biogeochemistry, which has driven exploration of the factors controlling biological parameters and processes. Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle. In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic. We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.

RF front-end world class designs

CERN Document Server

Love, Janine

2009-01-01

All the design and development inspiration and direction a harware engineer needs in one blockbuster book! Janine Love site editor for RF Design Line,columnist, and author has selected the very best RF design material from the Newnes portfolio and has compiled it into this volume. The result is a book covering the gamut of RF front end design from antenna and filter design fundamentals to optimized layout techniques with a strong pragmatic emphasis. In addition to specific design techniques and practices, this book also discusses various approaches to solving RF front end design problems and h

Front-end electronics for the upgraded GMRT

International Nuclear Information System (INIS)

Raut, Anil N; Bhalerao, Vilas; Kumar, A Praveen

2013-01-01

This paper first describes briefly the existing front-end receiver in use at the GMRT observatory and then details the ongoing development of next generation receiver systems for the upgraded GMRT. It covers the design of the new, two stage, room temperature, low noise amplifiers with better noise performance and matching, and improved dynamic range that are being implemented for the 130–260 MHz, 250–500 MHz and 550–900 MHz bands of the upgraded GMRT front-end systems.

Front propagation in flipping processes

International Nuclear Information System (INIS)

Antal, T; Ben-Avraham, D; Ben-Naim, E; Krapivsky, P L

2008-01-01

We study a directed flipping process that underlies the performance of the random edge simplex algorithm. In this stochastic process, which takes place on a one-dimensional lattice whose sites may be either occupied or vacant, occupied sites become vacant at a constant rate and simultaneously cause all sites to the right to change their state. This random process exhibits rich phenomenology. First, there is a front, defined by the position of the leftmost occupied site, that propagates at a nontrivial velocity. Second, the front involves a depletion zone with an excess of vacant sites. The total excess Δ k increases logarithmically, Δ k ≅ ln k, with the distance k from the front. Third, the front exhibits ageing-young fronts are vigorous but old fronts are sluggish. We investigate these phenomena using a quasi-static approximation, direct solutions of small systems and numerical simulations

Frozen reaction fronts in steady flows: A burning-invariant-manifold perspective

Science.gov (United States)

Mahoney, John R.; Li, John; Boyer, Carleen; Solomon, Tom; Mitchell, Kevin A.

2015-12-01

The dynamics of fronts, such as chemical reaction fronts, propagating in two-dimensional fluid flows can be remarkably rich and varied. For time-invariant flows, the front dynamics may simplify, settling in to a steady state in which the reacted domain is static, and the front appears "frozen." Our central result is that these frozen fronts in the two-dimensional fluid are composed of segments of burning invariant manifolds, invariant manifolds of front-element dynamics in x y θ space, where θ is the front orientation. Burning invariant manifolds (BIMs) have been identified previously as important local barriers to front propagation in fluid flows. The relevance of BIMs for frozen fronts rests in their ability, under appropriate conditions, to form global barriers, separating reacted domains from nonreacted domains for all time. The second main result of this paper is an understanding of bifurcations that lead from a nonfrozen state to a frozen state, as well as bifurcations that change the topological structure of the frozen front. Although the primary results of this study apply to general fluid flows, our analysis focuses on a chain of vortices in a channel flow with an imposed wind. For this system, we present both experimental and numerical studies that support the theoretical analysis developed here.

Targeting NCK-Mediated Endothelial Cell Front-Rear Polarity Inhibits Neovascularization.

Science.gov (United States)

Dubrac, Alexandre; Genet, Gael; Ola, Roxana; Zhang, Feng; Pibouin-Fragner, Laurence; Han, Jinah; Zhang, Jiasheng; Thomas, Jean-Léon; Chedotal, Alain; Schwartz, Martin A; Eichmann, Anne

2016-01-26

Sprouting angiogenesis is a key process driving blood vessel growth in ischemic tissues and an important drug target in a number of diseases, including wet macular degeneration and wound healing. Endothelial cells forming the sprout must develop front-rear polarity to allow sprout extension. The adaptor proteins Nck1 and 2 are known regulators of cytoskeletal dynamics and polarity, but their function in angiogenesis is poorly understood. Here, we show that the Nck adaptors are required for endothelial cell front-rear polarity and migration downstream of the angiogenic growth factors VEGF-A and Slit2. Mice carrying inducible, endothelial-specific Nck1/2 deletions fail to develop front-rear polarized vessel sprouts and exhibit severe angiogenesis defects in the postnatal retina and during embryonic development. Inactivation of NCK1 and 2 inhibits polarity by preventing Cdc42 and Pak2 activation by VEGF-A and Slit2. Mechanistically, NCK binding to ROBO1 is required for both Slit2- and VEGF-induced front-rear polarity. Selective inhibition of polarized endothelial cell migration by targeting Nck1/2 prevents hypersprouting induced by Notch or Bmp signaling inhibition, and pathological ocular neovascularization and wound healing, as well. These data reveal a novel signal integration mechanism involving NCK1/2, ROBO1/2, and VEGFR2 that controls endothelial cell front-rear polarity during sprouting angiogenesis. © 2015 American Heart Association, Inc.

Cold fronts in the Colombian Caribbean Sea and their relationship to extreme wave events

Science.gov (United States)

Ortiz-Royero, J. C.; Otero, L. J.; Restrepo, J. C.; Ruiz, J.; Cadena, M.

2013-11-01

Extreme ocean waves in the Caribbean Sea are commonly related to the effects of storms and hurricanes during the months of June through November. The collapse of 200 m of the Puerto Colombia pier in March 2009 revealed the effects of meteorological phenomena other than storms and hurricanes that may be influencing the extreme wave regime in the Colombian Caribbean. The marked seasonality of these atmospheric fronts was established by analyzing the meteorological-marine reports of the Instituto de Hidrología, Meteorología y Estudios Ambientales of Colombia (IDEAM, based on its initials in Spanish) and the Centro de Investigación en Oceanografía y Meteorología of Colombia (CIOH, based on its initials in Spanish) during the last 16 yr. The highest number of cold fronts was observed during the months of January, February, and March, with 6 fronts occurring per year. An annual trend was observed and the highest number of fronts occurred in 2010 (20 in total); moreover, an annual strong relationship between the maximum average wave values and the cold fronts in the central zone of the Colombian Caribbean during the first three months of the year was established. In addition, the maximum values of the significant height produced by the passage of cold fronts during the last 16 yr were identified. Although the Colombian Caribbean has been affected by storms and hurricanes in the past, this research allows us to conclude that there is a strong relationship between cold fronts and the largest waves in the Colombian Caribbean during the last 16 yr, which have caused damage to coastal infrastructure. We verified that the passage of a cold front corresponded to the most significant extreme wave event of the last two decades in the Colombian Caribbean, which caused the structural collapse of the Puerto Colombia pier, located near the city of Barranquilla, between 5 and 10 March 2009. This information is invaluable when evaluating average and extreme wave regimes for the

Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS

DEFF Research Database (Denmark)

de Juan, Julia; Elosegui, P.; Nettles, M.

-scales and beyond. We find that the flow velocity of Helheim Glacier is modulated by ocean tides in a region including both sides of the grounding line. An admittance analysis of the tidal signal shows an exponential decrease in amplitude with distance from the calving front, along with increasing time delays...

Crustal rifting and magmatic underplating in the Izu-Ogasawara (Bonin) intra-oceanic arc detected by active source seismic studies

Science.gov (United States)

Takahashi, N.; Kodaira, S.; Yamashita, M.; Miura, S.; Sato, T.; No, T.; Tatsumi, Y.; Kaneda, Y.

2009-12-01

Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has carried out seismic experiments using a multichannel reflection system and ocean bottom seismographs (OBSs) in the Izu-Ogasawara (Bonin)-Mariana (IBM) arc region since 2002 to understand growth process of continental crust. The source was an airgun array with a total capacity of 12,000 cubic inches and the OBSs as the receiver were deployed with an interval of 5 km for all seismic refraction experiments. As the results, we obtained crustal structures across the whole IBM arc with an interval of 50 km and detected the structural characteristics showing the crustal growth process. The IBM arc is one of typical oceanic island arc, which crustal growth started from subduction of an oceanic crust beneath the other oceanic crust. The arc crust has developed through repeatedly magmatic accretion from subduction slab and backarc opening. The volcanism has activated in Eocene, Oligocene, Miocene and Quaternary (e.g., Taylor, 1992), however, these detailed locations of past volcanic arc has been remained as one of unknown issues. In addition, a role of crustal rifting for the crustal growth has also been still unknown issue yet. Our seismic structures show three rows of past volcanic arc crusts except current arc. A rear arc and a forearc side have one and two, respectively. The first one, which was already reported by Kodaira et al. (2008), distributes in northern side from 27 N of the rear arc region. The second one, which develops in the forearc region next to the recent volcanic front, distributes in whole of the Izu-Ogasawara arc having crustal variation along arc direction. Ones of them sometimes have thicker crust than that beneath current volcanic front and no clear topographic high. Last one in the forearc connects to the Ogasawara Ridge. However, thickest crust is not always located beneath these volcanic arcs. The initial rifting region like the northern end of the Mariana Trough and the Sumisu

Photoionization effects in ionization fronts

International Nuclear Information System (INIS)

Arrayas, Manuel; Fontelos, Marco A; Trueba, Jose L

2006-01-01

In this paper we study the effects of photoionization processes on the propagation of both negative and positive ionization fronts in streamer discharge. We show that negative fronts accelerate in the presence of photoionization events. The appearance and propagation of positive ionization fronts travelling with constant velocity is explained as the result of the combined effects of photoionization and electron diffusion. The photoionization range plays an important role in the selection of the velocity of the ionization front as we show in this work

Photoionization effects in ionization fronts

Energy Technology Data Exchange (ETDEWEB)

Arrayas, Manuel [Departamento de Electromagnetismo, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Fontelos, Marco A [Departamento de Matematicas, Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones CientIficas, C/Serrano 123, 28006 Madrid (Spain); Trueba, Jose L [Departamento de Electromagnetismo, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)

2006-12-21

In this paper we study the effects of photoionization processes on the propagation of both negative and positive ionization fronts in streamer discharge. We show that negative fronts accelerate in the presence of photoionization events. The appearance and propagation of positive ionization fronts travelling with constant velocity is explained as the result of the combined effects of photoionization and electron diffusion. The photoionization range plays an important role in the selection of the velocity of the ionization front as we show in this work.

Active learning of Pareto fronts.

Science.gov (United States)

Campigotto, Paolo; Passerini, Andrea; Battiti, Roberto

2014-03-01

This paper introduces the active learning of Pareto fronts (ALP) algorithm, a novel approach to recover the Pareto front of a multiobjective optimization problem. ALP casts the identification of the Pareto front into a supervised machine learning task. This approach enables an analytical model of the Pareto front to be built. The computational effort in generating the supervised information is reduced by an active learning strategy. In particular, the model is learned from a set of informative training objective vectors. The training objective vectors are approximated Pareto-optimal vectors obtained by solving different scalarized problem instances. The experimental results show that ALP achieves an accurate Pareto front approximation with a lower computational effort than state-of-the-art estimation of distribution algorithms and widely known genetic techniques.

Systematic front distortion and presence of consecutive fronts in a precipitation system

NARCIS (Netherlands)

Volford, A.; Izsak, F.; Ripszam, M.; Lagzi, I.

2006-01-01

A new simple reaction-diffusion system is presented focusing on pattern formation phenomena as consecutive precipitation fronts and distortion of the precipitation front.The chemical system investigated here is based on the amphoteric property of aluminum hydroxide and exhibits two unique phenomena.

Mechanism of seasonal eddy kinetic energy variability in the eastern equatorial Pacific Ocean

Science.gov (United States)

Wang, Minyang; Du, Yan; Qiu, Bo; Cheng, Xuhua; Luo, Yiyong; Chen, Xiao; Feng, Ming

2017-04-01

Enhanced mesoscale eddy activities or tropical instability waves (TIWs) exist along the northern front of the cold tongue in the eastern equatorial Pacific Ocean. In this study, we investigate seasonal variability of eddy kinetic energy (EKE) over this region and its associated dynamic mechanism using a global, eddy-resolving ocean general circulation model (OGCM) simulation, the equatorial mooring data, and satellite altimeter observations. The seasonal-varying enhanced EKE signals are found to expand westward from 100°W in June to 180°W in December between 0°N and 6°N. This westward expansion in EKE is closely connected to the barotropically-baroclinically unstable zonal flows that are in thermal-wind balance with the seasonal-varying thermocline trough along 4°N. By adopting an 1½-layer reduced-gravity model, we confirm that the seasonal perturbation of the thermocline trough is dominated by the anticyclonic wind stress curl forcing, which develops due to southerly winds along 4°N from June to December.

The 360 Degree Fulldome Production "Clockwork Ocean"

Science.gov (United States)

Baschek, B.; Heinsohn, R.; Opitz, D.; Fischer, T.; Baschek, T.

2016-02-01

The investigation of submesoscale eddies and fronts is one of the leading oceanographic topics at the Ocean Sciences Meeting 2016. In order to observe these small and short-lived phenomena, planes equipped with high-resolution cameras and fast vessels were deployed during the Submesoscale Experiments (SubEx) leading to some of the first high-resolution observations of these eddies. In a future experiment, a zeppelin will be used the first time in marine sciences. The relevance of submesoscale processes for the oceans and the work of the eddy hunters is described in the fascinating 9-minute long 360 degree fulldome production Clockwork Ocean. The fully animated movie is introduced in this presentation taking the observer from the bioluminescence in the deep ocean to a view of our blue planet from space. The immersive media is used to combine fascination for a yet unknown environment with scientific education of a broad audience. Detailed background information is available at the parallax website www.clockwork-ocean.com. The Film is also available for Virtual Reality glasses and smartphones to reach a broader distribution. A unique Mobile Dome with an area of 70 m² and seats for 40 people is used for science education at events, festivals, for politicians and school classes. The spectators are also invited to participate in the experiments by presenting 360 degree footage of the measurements. The premiere of Clockwork Ocean was in July 2015 in Hamburg, Germany and will be worldwide available in English and German as of fall 2015. Clockwork Ocean is a film of the Helmholtz-Zentrum Geesthacht produced by Daniel Opitz and Ralph Heinsohn.

The evolution of a coupled ice shelf-ocean system under different climate states

Science.gov (United States)

Grosfeld, Klaus; Sandhäger, Henner

2004-07-01

Based on a new approach for coupled applications of an ice shelf model and an ocean general circulation model, we investigate the evolution of an ice shelf-ocean system and its sensitivity to changed climatic boundary conditions. Combining established 3D models into a coupled model system enabled us to study the reaction and feedbacks of each component to changes at their interface, the ice shelf base. After calculating the dynamics for prescribed initial ice shelf and bathymetric geometries, the basal mass balance determines the system evolution. In order to explore possible developments for given boundary conditions, an idealized geometry has been chosen, reflecting basic features of the Filchner-Ronne Ice Shelf, Antarctica. The model system is found to be especially sensitive in regions where high ablation or accretion rates occur. Ice Shelf Water formation as well as the build up of a marine ice body, resulting from accretion of marine ice, is simulated, indicating strong interaction processes. To improve consistency between modeled and observed ice shelf behavior, we incorporate the typical cycle of steady ice front advance and sudden retreat due to tabular iceberg calving in our time-dependent simulations. Our basic hypothesis is that iceberg break off is associated with abrupt crack propagation along elongated anomalies of the inherent stress field of the ice body. This new concept yields glaciologically plausible results and represents an auspicious basis for the development of a thorough calving criterion. Experiments under different climatic conditions (ocean warming of 0.2 and 0.5 °C and doubled surface accumulation rates) show the coupled model system to be sensitive especially to ocean warming. Increased basal melt rates of 100% for the 0.5 °C ocean warming scenario and an asymmetric development of ice shelf thicknesses suggest a high vulnerability of ice shelf regions, which represent pivotal areas between the Antarctic Ice Sheet and the Southern

CMOS front-end electronics for radiation sensors

CERN Document Server

AUTHOR|(CDS)2071026

2015-01-01

This book offers a comprehensive treatment of front-end electronics for radiation detection. It discusses the fundamental principles of signal processing for radiation detectors and describes circuits at the level of functional building blocks, omitting transistor-level implementation. It also covers important system-level topics commonly found in the world of front-end electronics for radiation sensors. The book develops the topics in detail, with a constant focus on practical problems. It also provides real implementation examples that offer insights and stimuli for more experienced engineers already working in the field.

Development of front-end electronics and TDC LSI for the ATLAS MDT

CERN Document Server

Arai, Y

2000-01-01

Architecture of the front-end electronics for the ATLAS muon precision chamber (MDT) is presented. Especially, test results of a prototype TDC chip are described in detail. The chip was fabricated in a 0.3 mu m CMOS gate-array technology. Measurements of critical elements of the chip such as the PLL, and data buffering circuits demonstrated adequate performance. The effect of gamma-ray irradiation, using a /sup 60/Co source, and neutron irradiation, were also examined. The test results revealed radiation tolerance adequate for the operation of the circuits in the environment of the ATLAS MDT. Mounting of the front-end electronics to the MDT is scheduled to start in the year 2001. (10 refs).

Idea management in support of pharmaceutical front end innovation

DEFF Research Database (Denmark)

Aagaard, Annabeth

2012-01-01

The pharmaceutical industry faces continuing pressures from rising R&D costs and depreciating value of patents, as patent lives is eroded by testing procedures and pressures from public authorities to cut health care costs. These challenges have increased the focus on shortening development times......, which again put pressure on the efficiency of front end innovation (FEI). In the attempt to overcome these various challenges pharmaceutical companies are looking for new models to support FEI. This paper explores in what way idea management can be applied as a tool in facilitation of front end...... innovation in practice. First I show through a literature study, how idea management and front end innovation are related and may support each other. Hereafter I apply an exploratory case study of front end innovation in eight medium to large pharmaceutical companies in examination of how idea management...

The development and application of a sub-channel code in ocean environment

International Nuclear Information System (INIS)

Wu, Pan; Shan, Jianqiang; Xiang, Xiong; Zhang, Bo; Gou, Junli; Zhang, Bin

2016-01-01

Highlights: • A sub-channel code named ATHAS/OE is developed for nuclear reactors in ocean environment. • ATHAS/OE is verified by another modified sub-channel code based on COBRA-IV. • ATHAS/OE is used to analyze thermal hydraulic of a typical SMR in heaving and rolling motion. • Calculation results show that ocean condition affect the thermal hydraulic of a reactor significantly. - Abstract: An upgraded version of ATHAS sub-channel code ATHAS/OE is developed for the investigation of the thermal hydraulic behavior of nuclear reactor core in ocean environment with consideration of heaving and rolling motion effect. The code is verified by another modified sub-channel code based on COBRA-IV and used to analyze the thermal hydraulic characteristics of a typical SMR under heaving and rolling motion condition. The calculation results show that the heaving and rolling motion affect the thermal hydraulic behavior of a reactor significantly.

Summertime sea surface temperature fronts associated with upwelling around the Taiwan Bank

Science.gov (United States)

Lan, Kuo-Wei; Kawamura, Hiroshi; Lee, Ming-An; Chang, Yi; Chan, Jui-Wen; Liao, Cheng-Hsin

2009-04-01

It is well known that upwelling of subsurface water is dominant around the Taiwan Bank (TB) and the Penghu (PH) Islands in the southern Taiwan Strait in summertime. Sea surface temperature (SST) frontal features and related phenomena around the TB upwelling and the PH upwelling were investigated using long-term AVHRR (1996-2005) and SeaWiFS (1998-2005) data received at the station of National Taiwan Ocean University. SST and chlorophyll-a (Chl-a) images with a spatial resolution of 0.01° were generated and used for the monthly SST and Chl-a maps. SST fronts were extracted from each SST images and gradient magnitudes (GMs); the orientations were derived for the SST fronts. Monthly maps of cold fronts where the cooler SSTs were over a shallower bottom were produced from the orientation. Areas with high GMs (0.1-0.2 °C/km) with characteristic shapes appeared at geographically fixed positions around the TB/PH upwelling region where SSTs were lower than the surrounding waters. The well-shaped high GMs corresponded to cold fronts. Two areas with high Chl-a were found around the TB and PH Islands. The southern border of the high-Chl-a area in the TB upwelling area was outlined by the high-GM area. Shipboard measurements of snapshot vertical sections of temperature (T) and salinity (S) along the PH Channel showed a dome structure east of PH Islands, over which low SST and high GM in the maps of the corresponding month were present. Clear evidence of upwelling (vertically uniform distributions of T and S) was indicated at the TB edge in the T and S sections close to TB upwelling. This case of upwelling may be caused by bottom currents ascending the TB slope as pointed out by previous studies. The position of low SSTs in the monthly maps matched the upwelling area, and the high GMs corresponded to the area of eastern surface fronts in the T/S sections.

Chaos of radiative heat-loss-induced flame front instability.

Science.gov (United States)

Kinugawa, Hikaru; Ueda, Kazuhiro; Gotoda, Hiroshi

2016-03-01

We are intensively studying the chaos via the period-doubling bifurcation cascade in radiative heat-loss-induced flame front instability by analytical methods based on dynamical systems theory and complex networks. Significant changes in flame front dynamics in the chaotic region, which cannot be seen in the bifurcation diagrams, were successfully extracted from recurrence quantification analysis and nonlinear forecasting and from the network entropy. The temporal dynamics of the fuel concentration in the well-developed chaotic region is much more complicated than that of the flame front temperature. It exhibits self-affinity as a result of the scale-free structure in the constructed visibility graph.

Sustainability in the front-end of innovation at design agencies

NARCIS (Netherlands)

Storaker, A.; Wever, R.; Dewulf, K.; Blankenburg, D.

2013-01-01

In the two last decades a considerable amount of research has been conducted on the Front End of Innovation. This is the stage of the product development process where the design brief is formulated. This phase is argued to be crucial to the success of the final product. While the Front End of

HINS Linac front end focusing system R&D

Energy Technology Data Exchange (ETDEWEB)

Apollinari, G.; Carcagno, R.H.; Dimarco, J.; Huang, Y.; Kashikhin, V.V.; Orris, D.F.; Page, T.M.; Rabehl, R.; Sylvester, C.; Tartaglia, M.A.; Terechkine, I.; /Fermilab /Argonne

2008-08-01

This report summarizes current status of an R&D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process.

Ocean tides

Science.gov (United States)

Hendershott, M. C.

1975-01-01

A review of recent developments in the study of ocean tides and related phenomena is presented. Topics briefly discussed include: the mechanism by which tidal dissipation occurs; continental shelf, marginal sea, and baroclinic tides; estimation of the amount of energy stored in the tide; the distribution of energy over the ocean; the resonant frequencies and Q factors of oceanic normal modes; the relationship of earth tides and ocean tides; and numerical global tidal models.

Design of analog front-ends for the RD53 demonstrator chip

CERN Document Server

Gaioni, L; Nodari, B; Manghisoni, M; Re, V; Traversi, G; Barbero, M B; Fougeron, D; Gensolen, F; Godiot, S; Menouni, M; Pangaud, P; Rozanov, A; Wang, A; Bomben, M; Calderini, G; Crescioli, F; Le Dortz, O; Marchiori, G; Dzahini, D; Rarbi, F E; Gaglione, R; Gonella, L; Hemperek, T; Huegging, F; Karagounis, M; Kishishita, T; Krueger, H; Rymaszewski, P; Wermes, N; Ciciriello, F; Corsi, F; Marzocca, C; De Robertis, G; Loddo, F; Licciulli, F; Andreazza, A; Liberali, V; Shojaii, S; Stabile, A; Bagatin, M; Bisello, D; Mattiazzo, S; Ding, L; Gerardin, S; Giubilato, P; Neviani, A; Paccagnella, A; Vogrig, D; Wyss, J; Bacchetta, N; Della Casa, G; Demaria, N; Mazza, G; Rivetti, A; Da Rocha Rolo, M D; Comotti, D; Ratti, L; Vacchi, C; Beccherle, R; Bellazzini, R; Magazzu, G; Minuti, M; Morsani, F; Palla, F; Poulios, S; Fanucci, L; Rizzi, A; Saponara, S; Androsov, K; Bilei, G M; Menichelli, M; Conti, E; Marconi, S; Passeri, D; Placidi, P; Monteil, E; Pacher, L; Paternò, A; Gajanana, D; Gromov, V; Hessey, N; Kluit, R; Zivkovic, V; Havranek, M; Janoska, Z; Marcisovsky, M; Neue, G; Tomasek, L; Kafka, V; Sicho, P; Vrba, V; Vila, I; Lopez-Morillo, E; Aguirre, M A; Palomo, F R; Muñoz, F; Abbaneo, D; Christiansen, J; Dannheim, D; Dobos, D; Linssen, L; Pernegger, H; Valerio, P; Alipour Tehrani, N; Bell, S; Prydderch, M L; Thomas, S; Christian, D C; Fahim, F; Hoff, J; Lipton, R; Liu, T; Zimmerman, T; Garcia-Sciveres, M; Gnani, D; Mekkaoui, A; Gorelov, I; Hoeferkamp, M; Seidel, S; Toms, K; De Witt, J N; Grillo, A

2017-01-01

The RD53 collaboration is developing a large scale pixel front-end chip, which will be a tool to evaluate the performance of 65 nm CMOS technology in view of its application to the readout of the innermost detector layers of ATLAS and CMS at the HL-LHC. Experimental results of the characterization of small prototypes will be discussed in the frame of the design work that is currently leading to the development of the large scale demonstrator chip RD53A to be submitted in early 2017. The paper is focused on the analog processors developed in the framework of the RD53 collaboration, including three time over threshold front-ends, designed by INFN Torino and Pavia, University of Bergamo and LBNL and a zero dead time front-end based on flash ADC designed by a joint collaboration between the Fermilab and INFN. The paper will also discuss the radiation tolerance features of the front-end channels, which were exposed to up to 800 Mrad of total ionizing dose to reproduce the system operation in the actual experiment.

Multiple stable isotope fronts during non-isothermal fluid flow

Science.gov (United States)

Fekete, Szandra; Weis, Philipp; Scott, Samuel; Driesner, Thomas

2018-02-01

Stable isotope signatures of oxygen, hydrogen and other elements in minerals from hydrothermal veins and metasomatized host rocks are widely used to investigate fluid sources and paths. Previous theoretical studies mostly focused on analyzing stable isotope fronts developing during single-phase, isothermal fluid flow. In this study, numerical simulations were performed to assess how temperature changes, transport phenomena, kinetic vs. equilibrium isotope exchange, and isotopic source signals determine mineral oxygen isotopic compositions during fluid-rock interaction. The simulations focus on one-dimensional scenarios, with non-isothermal single- and two-phase fluid flow, and include the effects of quartz precipitation and dissolution. If isotope exchange between fluid and mineral is fast, a previously unrecognized, significant enrichment in heavy oxygen isotopes of fluids and minerals occurs at the thermal front. The maximum enrichment depends on the initial isotopic composition of fluid and mineral, the fluid-rock ratio and the maximum change in temperature, but is independent of the isotopic composition of the incoming fluid. This thermally induced isotope front propagates faster than the signal related to the initial isotopic composition of the incoming fluid, which forms a trailing front behind the zone of transient heavy oxygen isotope enrichment. Temperature-dependent kinetic rates of isotope exchange between fluid and rock strongly influence the degree of enrichment at the thermal front. In systems where initial isotope values of fluids and rocks are far from equilibrium and isotope fractionation is controlled by kinetics, the temperature increase accelerates the approach of the fluid to equilibrium conditions with the host rock. Consequently, the increase at the thermal front can be less dominant and can even generate fluid values below the initial isotopic composition of the input fluid. As kinetics limit the degree of isotope exchange, a third front may

Examining the plankton acoustic response with a vessel mounted ADCP across oceanic fronts located in the Drake Passage

Directory of Open Access Journals (Sweden)

Silvia Blanc

2008-12-01

Full Text Available On December 2001 and January 2006, during the LMG01-9 and LMG06-1 cruises to Antarctic Peninsula, at-sea oceanographic and acoustic measurements were conducted onboard the R/V L. M. Gould icebreaker along two transects located between (55.15 °S, 65 ºW and (64.65 °S, 65 ºW and between (55.15 ºS, 64.91 ºW and (62.7 ºS, 62.21 ºW, respectively. The scientific crew consisted of researchers from two US institutes, and a scientific observer from the Argentinean Naval Service of Research & Development under the frame of the US National Science Foundation Antarctic Program. The present work accomplishes an alternative application for a vesselmounted Acoustic Doppler Current Profiler (ADCP with an operating frequency of 153.6 kHz. Volume Acoustic Backscattering Strengths, S V, were computed from the recorded ADCP's voltages. The obtained values fell in a range of -92 dB to -62 dB, for the layer of the water column comprised between 26 m - 300 m on 2001 and in the range of -93 dB to -58 dB for the water column between 22 m - 300 m on 2006. Depth-averaged, S V, for the upper water column (about the first 150 m on experiment transects were computed as well as S V values averaged in depth and latitude. Data processing revealed interesting features about the upper ocean acoustic behaviour. On December 2001, a significant non-uniform scattering response in the ensonified water column with quite high values of S V, associated with the diel vertical migration, was obtained. Additionally, a remarkable increment in the scattering response was observed at the estimated location of the Antarctic Divergence (AD. This feature was also observed on January 2006 in addition to remarkable high values of S V, in coastal waters of the Antarctic Peninsula. Plotting and exhaustive analyses of S V (z profiles enabled the visualisation of three distinct types of qualitative patterns, namely, curves with: (I two observable maxima, (II only one maximum, (III a depth

PIV tracer behavior on propagating shock fronts

International Nuclear Information System (INIS)

Glazyrin, Fyodor N; Mursenkova, Irina V; Znamenskaya, Irina A

2016-01-01

The present work was aimed at the quantitative particle image velocimetry (PIV) measurement of a velocity field near the front of a propagating shock wave and the study of the dynamics of liquid tracers crossing the shock front. For this goal, a shock tube with a rectangular cross-section (48  ×  24 mm) was used. The flat shock wave with Mach numbers M  =  1.4–2.0 propagating inside the tube channel was studied as well as an expanding shock wave propagating outside the channel with M  =  1.2–1.8 at its main axis. The PIV imaging of the shock fronts was carried out with an aerosol of dioctyl sebacate (DEHS) as tracer particles. The pressures of the gas in front of the shock waves studied ranged from 0.013 Mpa to 0.1 MPa in the series of experiments. The processed PIV data, compared to the 1D normal shock theory, yielded consistent values of wake velocity immediately behind the plain shock wave. Special attention was paid to the blurring of the velocity jump on the shock front due to the inertial particle lag and peculiarities of the PIV technique. A numerical algorithm was developed for analysis and correction of the PIV data on the shock fronts, based on equations of particle-flow interaction. By application of this algorithm, the effective particle diameter of the DEHS aerosol tracers was estimated as 1.03  ±  0.12 μm. A number of different formulations for particle drag were tested with this algorithm, with varying success. The results show consistency with previously reported experimental data obtained for cases of stationary shock waves. (paper)

Targeting NCK-Mediated Endothelial Cell Front-Rear Polarity Inhibits Neo-Vascularization

Science.gov (United States)

Dubrac, Alexandre; Genet, Gael; Ola, Roxana; Zhang, Feng; Pibouin-Fragner, Laurence; Han, Jinah; Zhang, Jiasheng; Thomas, Jean-Léon; Chedotal, Alain; Schwartz, Martin A.; Eichmann, Anne

2015-01-01

Background Sprouting angiogenesis is a key process driving blood vessel growth in ischemic tissues and an important drug target in a number of diseases, including wet macular degeneration and wound healing. Endothelial cells forming the sprout must develop front-rear polarity to allow sprout extension. The adaptor proteins Nck1 and 2 are known regulators of cytoskeletal dynamics and polarity, but their function in angiogenesis is poorly understood. Here we show that the Nck adaptors are required for endothelial cell front-rear polarity and migration downstream of the angiogenic growth factors VEGF-A and Slit2. Methods and Results Mice carrying inducible, endothelial-specific Nck1/2 deletions fail to develop front-rear polarized vessel sprouts and exhibit severe angiogenesis defects in the postnatal retina and during embryonic development. Inactivation of NCK1 and 2 inhibits polarity by preventing Cdc42 and Pak2 activation by VEGF-A and Slit2. Mechanistically, NCK binding to ROBO1 is required for both Slit2 and VEGF induced front-rear polarity. Selective inhibition of polarized endothelial cell migration by targeting Nck1/2 prevents hypersprouting induced by Notch or Bmp signaling inhibition, as well as pathological ocular neovascularization and wound healing. Conclusions These data reveal a novel signal integration mechanism involving NCK1/2, ROBO1/2 and VEGFR2 that controls endothelial cell front-rear polarity during sprouting angiogenesis. PMID:26659946

Ocean wave generation by collapsing ice shelves

Science.gov (United States)

Macayeal, D. R.; Bassis, J. N.; Okal, E. A.; Aster, R. C.; Cathles, L. M.

2008-12-01

The 28-29 February, 2008, break-up of the Wilkins Ice Shelf, Antarctica, exemplifies the now-familiar, yet largely unexplained pattern of explosive ice-shelf break-up. While environmental warming is a likely ultimate cause of explosive break-up, several key aspects of their short-term behavior need to be explained: (1) The abrupt, near-simultaneous onset of iceberg calving across long spans of the ice front margin; (2) High outward drift velocity (about 0.3 m/s) of a leading phalanx of tabular icebergs that originate from the seaward edge of the intact ice shelf prior to break-up; (3) Rapid coverage of the ocean surface in the wake of this leading phalanx by small, capsized and dismembered tabular icebergs; (4) Extremely large gravitational potential energy release rates, e.g., up to 3 × 1010 W; (5) Lack of proximal iceberg-calving triggers that control the timing of break-up onset and that maintain the high break-up calving rates through to the conclusion of the event. Motivated by seismic records obtained from icebergs and the Ross Ice Shelf that show hundreds of micro- tsunamis emanating from near the ice shelf front, we re-examine the basic dynamic features of ice- shelf/ocean-wave interaction and, in particular, examine the possibility that collapsing ice shelves themselves are a source of waves that stimulate the disintegration process. We propose that ice-shelf generated surface-gravity waves associated with initial calving at an arbitrary seed location produce stress perturbations capable of triggering the onset of calving on the entire ice front. Waves generated by parting detachment rifts, iceberg capsize and break-up act next to stimulate an inverted submarine landslide (ice- slide) process, where gravitational potential energy released by upward movement of buoyant ice is radiated as surface gravity waves in the wake of the advancing phalanx of tabular icebergs. We conclude by describing how field research and remote sensing can be used to test the

Measurement of Design Process Front-End – Radical Innovation Approach

DEFF Research Database (Denmark)

Berg, Pekka; Pihlajamaa, Jussi; Hansen, Poul H. Kyvsgård

2014-01-01

The overall structure and the main characteristics of the future product are all decided in the front-end phase, which then strongly affects subsequent new product development activities. Recent studies indicate that these early front-end activities represent the most troublesome phase...... of the innovation process, and at the same time one of the greatest opportunities to improve the overall innovation capability of a company. In this paper dealing with the criteria we concentrate only for the objectives viewpoint and leave the attributes discussion to the future research. Two most crucial questions...... the innovation activities front end contains five assessment viewpoints as follows; input, process, output (including impacts), social environment and structural environment. Based on the results from our first managerial implications in three Finnish manufacturing companies we argue, that the developed model...

Multiple Scale Reaction-Diffusion-Advection Problems with Moving Fronts

Science.gov (United States)

Nefedov, Nikolay

2016-06-01

In this work we discuss the further development of the general scheme of the asymptotic method of differential inequalities to investigate stability and motion of sharp internal layers (fronts) for nonlinear singularly perturbed parabolic equations, which are called in applications reaction-diffusion-advection equations. Our approach is illustrated for some new important cases of initial boundary value problems. We present results on stability and on the motion of the fronts.

Hydrodynamic instabilities in an ablation front

International Nuclear Information System (INIS)

Piriz, A R; Portugues, R F

2004-01-01

The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved

Hydrodynamic instabilities in an ablation front

Energy Technology Data Exchange (ETDEWEB)

Piriz, A R; Portugues, R F [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)

2004-06-01

The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved.

Oceanic migration and spawning of anguillid eels.

Science.gov (United States)

Tsukamoto, K

2009-06-01

Many aspects of the life histories of anguillid eels have been revealed in recent decades, but the spawning migrations of their silver eels in the open ocean still remains poorly understood. This paper overviews what is known about the migration and spawning of anguillid species in the ocean. The factors that determine exactly when anguillid eels will begin their migrations are not known, although environmental influences such as lunar cycle, rainfall and river discharge seem to affect their patterns of movement as they migrate towards the ocean. Once in the ocean on their way to the spawning area, silver eels probably migrate in the upper few hundred metres, while reproductive maturation continues. Although involvement of a magnetic sense or olfactory cues seems probable, how they navigate or what routes they take are still a matter of speculation. There are few landmarks in the open ocean to define their spawning areas, other than oceanographic or geological features such as oceanic fronts or seamounts in some cases. Spawning of silver eels in the ocean has never been observed, but artificially matured eels of several species have exhibited similar spawning behaviours in the laboratory. Recent collections of mature adults and newly spawned preleptocephali in the spawning area of the Japanese eel Anguilla japonica have shown that spawning occurs during new moon periods in the North Equatorial Current region near the West Mariana Ridge. These data, however, show that the latitude of the spawning events can change among months and years depending on oceanographic conditions. Changes in spawning location of this and other anguillid species may affect their larval transport and survival, and appear to have the potential to influence recruitment success. A greater understanding of the spawning migration and the choice of spawning locations by silver eels is needed to help conserve declining anguillid species.

A Multi-Process Test Case to Perform Comparative Analysis of Coastal Oceanic Models

Science.gov (United States)

Lemarié, F.; Burchard, H.; Knut, K.; Debreu, L.

2016-12-01

Due to the wide variety of choices that need to be made during the development of dynamical kernels of oceanic models, there is a strong need for an effective and objective assessment of the various methods and approaches that predominate in the community. We present here an idealized multi-scale scenario for coastal ocean models combining estuarine, coastal and shelf sea scales at midlatitude. The bathymetry, initial conditions and external forcings are defined analytically so that any model developer or user could reproduce the test case with its own numerical code. Thermally stratified conditions are prescribed and a tidal forcing is imposed as a propagating coastal Kelvin wave. The following physical processes can be assessed from the model results: estuarine process driven by tides and buoyancy gradients, the river plume dynamics, tidal fronts, and the interaction between tides and inertial oscillations. We show results obtained using the GETM (General Estuarine Transport Model) and the CROCO (Coastal and Regional Ocean Community model) models. Those two models are representative of the diversity of numerical methods in use in coastal models: GETM is based on a quasi-lagrangian vertical coordinate, a coupled space-time approach for advective terms, a TVD (Total Variation Diminishing) tracer advection scheme while CROCO is discretized with a quasi-eulerian vertical coordinate, a method of lines is used for advective terms, and tracer advection satisfies the TVB (Total Variation Bounded) property. The multiple scales are properly resolved thanks to nesting strategies, 1-way nesting for GETM and 2-way nesting for CROCO. Such test case can be an interesting experiment to continue research in numerical approaches as well as an efficient tool to allow intercomparison between structured-grid and unstructured-grid approaches. Reference : Burchard, H., Debreu, L., Klingbeil, K., Lemarié, F. : The numerics of hydrostatic structured-grid coastal ocean models: state of

Kinetics of a plasma streamer ionization front

Science.gov (United States)

Taccogna, Francesco; Pellegrini, Fabrizio

2018-02-01

A streamer is a non-linear and non-local gas breakdown mode. Its large-scale coherent structures, such as the ionization front, are the final results of a hierarchical cascade starting from the single particle dynamics. Therefore, this phenomenon covers, by definition, different space and time scales. In this study, we have reproduced the ionization front formation and development by means of a particle-based numerical methodology. The physical system investigated concerns of a high-voltage ns-pulsed surface dielectric barrier discharge. Different reduced electric field regimes ranging from 50 to 500 Td have been considered for two gases: pure atomic Ar and molecular N2. Results have shown the detailed structure of the negative streamer: the leading edge, the head, the interior and the tail. Its dynamical evolution and the front propagation velocity have been calculated for the different cases. Finally, the deviation of the electron energy distribution function from equilibrium behavior has been pointed out as a result of a fast and very localized phenomenon.

Front end readout electronics for the CMS hadron calorimeter

CERN Document Server

Shaw, Terri M

2002-01-01

The front-end electronics for the CMS Hadron Calorimeter provides digitized data at the beam interaction rate of 40 MHz. Analog signals provided by hybrid photodiodes (HPDs) or photomultiplier tubes (PMTs) are digitized and the data is sent off board through serialized fiber optic links running at 1600 Mbps. In order to maximize the input signal, the front-end electronics are housed on the detector in close proximity to the scintillating fibers or phototubes. To fit the electronics into available space, custom crates, backplanes and cooling methods have had to be developed. During the expected ten-year lifetime, the front-end readout electronics will exist in an environment where radiation levels approach 330 rads and the neutron fluence will be 1.3E11 n/cm sup 2. For this reason, the design approach relies heavily upon custom radiation tolerant ASICs. This paper will present the system architecture of the front-end readout crates and describe their results with early prototypes.

Front end readout electronics for the CMS hadron calorimeter

International Nuclear Information System (INIS)

Terri M. Shaw et al.

2002-01-01

The front-end electronics for the CMS Hadron Calorimeter provides digitized data at the beam interaction rate of 40 MHz. Analog signals provided by hybrid photodiodes (HPDs) or photomultiplier tubes (PMTs) are digitized and the data is sent off board through serialized fiber optic links running at 1600 Mbps. In order to maximize the input signal, the front-end electronics are housed on the detector in close proximity to the scintillating fibers or phototubes. To fit the electronics into available space, custom crates, backplanes and cooling methods have had to be developed. During the expected ten-year lifetime, the front-end readout electronics will exist in an environment where radiation levels approach 330 rads and the neutron fluence will be 1.3E11 n/cm 2 . For this reason, the design approach relies heavily upon custom radiation tolerant ASICs. This paper will present the system architecture of the front-end readout crates and describe their results with early prototypes

Transverse tectonic structural elements across Himalayan mountain front, eastern Arunachal Himalaya, India: Implication of superposed landform development on analysis of neotectonics

Science.gov (United States)

Bhakuni, S. S.; Luirei, Khayingshing; Kothyari, Girish Ch.; Imsong, Watinaro

2017-04-01

Structural and morphotectonic signatures in conjunction with the geomorphic indices are synthesised to trace the role of transverse tectonic features in shaping the landforms developed along the frontal part of the eastern Arunachal sub-Himalaya. Mountain front sinuosity (Smf) index values close to one are indicative of the active nature of the mountain front all along the eastern Arunachal Himalaya, which can be directly attributed to the regional uplift along the Himalayan Frontal Thrust (HFT). However, the mountain front is significantly sinusoidal around junctions between HFT/MBT (Main Boundary Thrust) and active transverse faults. The high values of stream length gradient (SL) and stream steepness (Ks) indices together with field evidence of fault scarps, offset of terraces, and deflection of streams are markers of neotectonic uplift along the thrusts and transverse faults. This reactivation of transverse faults has given rise to extensional basins leading to widening of the river courses, providing favourable sites for deposition of recent sediments. Tectonic interactions of these transverse faults with the Himalayan longitudinal thrusts (MBT/HFT) have segmented the mountain front marked with varying sinuosity. The net result is that a variety of tectonic landforms recognized along the mountain front can be tracked to the complex interactions among the transverse and longitudinal tectonic elements. Some distinctive examples are: in the eastern extremity of NE Himalaya across the Dibang River valley, the NW-SE trending mountain front is attenuated by the active Mishmi Thrust that has thrust the Mishmi crystalline complex directly over the alluvium of the Brahmaputra plains. The junction of the folded HFT and Mishmi Thrust shows a zone of brecciated and pulverized rocks along which transverse axial planar fracture cleavages exhibit neotectonic activities in a transverse fault zone coinciding with the Dibang River course. Similarly, the transverse faults cut the

FROM CONTROVERSY TO TOLERANCE: Dynamics of the Development of Istiqomah Mosque in Front of a Church in Ungaran Central Java Indonesia

Directory of Open Access Journals (Sweden)

Muh Saerozi

2017-12-01

Full Text Available This study aims to reveal the dynamic of the development of a mosque in front of a church: the case study of Istiqomah Mosque of Ungaran. The dynamics of the development is seen from some factors that encouraged the establishment of the mosque, the phenomenon of controversy, the problem solution, and the development of tolerance model. The study uses a historical-qualitative approach. The primary data are gathered from interviews, documentation, and observation. The purposes of building the mosque were to balance the national development, to prevent the influence of the Partai Komunis Indonesia (PKI, Indonesian Communist Party, and to create a symbol of tolerance. Controversy occurred in the process of construction because some political and religious elites considered the mosque as political Islam. The controversy waned after the New Order’s elites supported the construction of the mosque. The implementation of a moderate Islamic principles influenced the mosque in building tolerance to the Kristus Raja church in front of it.

Dynamic estuarine plumes and fronts: importance to small fish and plankton in coastal waters of NSW, Australia

Science.gov (United States)

Kingsford, M. J.; Suthers, I. M.

1994-05-01

In 1990, low density estuarine plumes in the vicinity of Botany Bay, Australia, extended up to 11 km across a narrow continental shelf ( ca 25 km) on ebb tides. The shape and seaward extent of plumes varied according to a combination of state of the tide, freshwater input and the direction and intensity of coastal currents. Offshore plumes dissipated on the flood tide and fronts reformed at the entrance of Botany Bay. Major differences in the abundance and composition of ichthyoplankton and other zooplankton were found over a 400-800 m stretch of water encompassing waters of the plume, front and ocean on seven occasions. For example, highest abundances of the fishes Gobiidae, Sillaginidae, Gerreidae and Sparidae as well as barnacle larvae and fish eggs were found in plumes. Cross-shelf distribution patterns of zooplankton, therefore, are influenced by plumes. Distinct assemblages of plankters accumulated in fronts, e.g. fishes of the Mugilidae and Gonorynchidae and other zooplankters (e.g. Jaxea sp.). Accumulation in fronts was variable and may relate to variable convergence according to the tide. We argue that plumes provide a significant cue to larvae in coastal waters that an estuary is nearby. Moreover, although many larvae may be retained in the turbid waters of plumes associated with riverine input, larvae are potentially exported in surface waters on ebb tides.

Mobile Ocean Test Berth Support: Cooperative Research and Development Final Report, CRADA Number CRD-10-413

Energy Technology Data Exchange (ETDEWEB)

LiVecchi, Albert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-12-01

The Northwest National Marine Renewable Energy Center (NNMREC), headquartered at the Oregon State University, is establishing the capabilities to test prototype wave energy conversion devices in the ocean. This CRADA will leverage the technical expertise and resources at NREL in the wind industry and in ocean engineering to support and enhance the development of the NNMREC Mobile Ocean Test Berth (MOTB). This CRADA will provide direct support to NNMREC by providing design evaluation and review of the MOTB, developing effective protocols for testing of the MOTB and wave energy conversion devices in the ocean, assisting in the specification of appropriate instrumentation and data acquisition packages, and providing guidance on obtaining and maintaining A2LA (American Association for Laboratory Accreditation) accreditation.

Performance evaluation of the analogue front-end and ADC prototypes for the Gotthard-II development

Science.gov (United States)

Zhang, J.; Andrä, M.; Barten, R.; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Redford, S.; Ruat, M.; Ruder, C.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Turcato, M.; Vetter, S.

2017-12-01

Gotthard-II is a silicon microstrip detector developed for the European X-ray Free-Electron Laser (XFEL.EU). Its potential scientific applications include X-ray absorption/emission spectroscopy, hard X-ray high resolution single-shot spectrometry (HiREX), energy dispersive experiments at 4.5 MHz frame rate, beam diagnostics, as well as veto signal generation for pixel detectors. Gotthard-II uses a silicon microstrip sensor with a pitch of 50 μm or 25 μm and with 1280 or 2560 channels wire-bonded to readout chips (ROCs). In the ROC, an adaptive gain switching pre-amplifier (PRE), a fully differential Correlated-Double-Sampling (CDS) stage, an Analog-to-Digital Converter (ADC) as well as a Static Random-Access Memory (SRAM) capable of storing all the 2700 images in an XFEL.EU bunch train will be implemented. Several prototypes with different designs of the analogue front-end (PRE and CDS) and ADC test structures have been fabricated in UMC-110 nm CMOS technology and their performance has been evaluated. In this paper, the performance of the analogue front-end and ADC will be summarized.

Gravity wave generation from jets and fronts: idealized and real-case simulations

Science.gov (United States)

Plougonven, Riwal; Arsac, Antonin; Hertzog, Albert; Guez, Lionel; Vial, François

2010-05-01

The generation of gravity waves from jets and fronts remains an outstanding issue in the dynamics of the atmosphere. It is important to explain and quantify this emission because of the several impacts of these waves, in particular the induced momentum fluxes towards the middle atmosphere, and their contribution to turbulence and mixing, e.g. in the region of the tropopause. Yet, the mechanisms at the origin of these waves have been difficult to identify, the fundamental reason for this being the separation between the time scales of balanced motions and gravity waves. Recent simulations of idealized baroclinic life cycles and of dipoles have provided insights into the mechanisms determining the characteristics and the amplitude of gravity waves emitted by jets. It has been shown in particular that the environmental strain and shear play a crucial role in determining the characteristics and location of the emitted waves, emphasizing jet exit regions for the appearance of coherent low-frequency waves. It has also been shown how advection of relatively small-scales allow to overcome the separation of time scales alluded to above. Recent results, remaining open questions and ongoing work on these idealized simulations will be briefly summarized. Nevertheless, unavoidable shortcomings of such idealized simulations include the sensitivity of the emitted waves to model setup (resolution, diffusion, parameterizations) and uncertainty regarding the realism of this aspect of the simulations. Hence, it is necessary to compare simulations with observations in order to assess their relevance. Such comparison has been undertaken using the dataset from the Vorcore campaign (Sept. 2005 - Feb. 2006, Hertzog, J. Atmos. Ocean. Techno. 2007) during which 27 superpressure balloons drifted as quasi-Lagrangian tracers in the lower stratosphere above Antarctica and the Southern Ocean. High-resolution simulations (dx = 20 km) have been carried out using the Weather Research and Forecast

THREE PERSPECTIVES ON MANAGING FRONT END INNOVATION

DEFF Research Database (Denmark)

Jensen, Anna Rose Vagn; Clausen, Christian; Gish, Liv

2018-01-01

as a complementary perspective. The paper combines a literature review with an empirical examination of the application of these multiple perspectives across three cases of front end of innovation (FEI) management in mature product developing companies. While the process models represent the dominant, albeit rather...... to represent an emergent approach in managing FEI where process models, knowledge strategies and objects become integrated elements in more advanced navigational strategies for key players.......This paper presents three complementary perspectives on the management of front end innovation: A process model perspective, a knowledge perspective and a translational perspective. While the first two perspectives are well established in literature, we offer the translation perspective...

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

Science.gov (United States)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

2017-12-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

QCD and Light-Front Dynamics

International Nuclear Information System (INIS)

Brodsky, Stanley J.; de Teramond, Guy F.

2011-01-01

AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate ζ which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its β-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include QCD interaction terms. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.

QCD and Light-Front Dynamics

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; de Teramond, Guy F.; /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.

2011-01-10

AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its {beta}-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include QCD interaction terms. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.

Extratropical Cyclone in the Southern Ocean

Science.gov (United States)

2002-01-01

These images from the Multi-angle Imaging SpectroRadiometer (MISR) portray an occluded extratropical cyclone situated in the Southern Ocean, about 650 kilometers south of the Eyre Peninsula, South Australia. The left-hand image, a true-color view from MISR's nadir (vertical-viewing) camera, shows clouds just south of the Yorke Peninsula and the Murray-Darling river basin in Australia. Retrieved cloud-tracked wind velocities are indicated by the superimposed arrows. The image on the right displays cloud-top heights. Areas where cloud heights could not be retrieved are shown in black. Both the wind vectors and the cloud heights were derived using data from multiple MISR cameras within automated computer processing algorithms. The stereoscopic algorithms used to generate these results are still being refined, and future versions of these products may show modest changes. Extratropical cyclones are the dominant weather system at midlatitudes, and the term is used generically for regional low-pressure systems in the mid- to high-latitudes. In the southern hemisphere, cyclonic rotation is clockwise. These storms obtain their energy from temperature differences between air masses on either side of warm and cold fronts, and their characteristic pattern is of warm and cold fronts radiating out from a migrating low pressure center which forms, deepens, and dissipates as the fronts fold and collapse on each other. The center of this cyclone has started to decay, with the band of cloud to the south most likely representing the main front that was originally connected with the cyclonic circulation. These views were acquired on October 11, 2001, and the large view represents an area of about 380 kilometers x 1900 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team.

Characterisation of the Interaction between Toroidal Vortex Structures and Flame Front Propagation

International Nuclear Information System (INIS)

Long, E J; Hargrave, G K; Jarvis, S; Justham, T; Halliwell, N

2006-01-01

Experimental laser diagnostic data is presented for flame characterisation during interactions with toroidal vortices generated in the wake of an annular obstacle. A novel twin section combustion chamber has been utilised to allow the controlled formation of stable eddy structures into which a flame front can propagate. High speed laser sheet visualisation was employed to record the flow field and flame front temporal development and high-speed digital particle image velocimetry was used to quantify the velocity field of the unburnt mixture ahead of the flame front. Results provide characterisation of the toroidal vortex/flame front interaction for a range of vortex scales of and recirculation strengths

Characterisation of the Interaction between Toroidal Vortex Structures and Flame Front Propagation

Energy Technology Data Exchange (ETDEWEB)

Long, E J; Hargrave, G K; Jarvis, S; Justham, T; Halliwell, N [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom)

2006-07-15

Experimental laser diagnostic data is presented for flame characterisation during interactions with toroidal vortices generated in the wake of an annular obstacle. A novel twin section combustion chamber has been utilised to allow the controlled formation of stable eddy structures into which a flame front can propagate. High speed laser sheet visualisation was employed to record the flow field and flame front temporal development and high-speed digital particle image velocimetry was used to quantify the velocity field of the unburnt mixture ahead of the flame front. Results provide characterisation of the toroidal vortex/flame front interaction for a range of vortex scales of and recirculation strengths.

Characterisation of the Interaction between Toroidal Vortex Structures and Flame Front Propagation

Science.gov (United States)

Long, E. J.; Hargrave, G. K.; Jarvis, S.; Justham, T.; Halliwell, N.

2006-07-01

Experimental laser diagnostic data is presented for flame characterisation during interactions with toroidal vortices generated in the wake of an annular obstacle. A novel twin section combustion chamber has been utilised to allow the controlled formation of stable eddy structures into which a flame front can propagate. High speed laser sheet visualisation was employed to record the flow field and flame front temporal development and high-speed digital particle image velocimetry was used to quantify the velocity field of the unburnt mixture ahead of the flame front. Results provide characterisation of the toroidal vortex/flame front interaction for a range of vortex scales of and recirculation strengths.

Fluctuation charge effects in ionization fronts

International Nuclear Information System (INIS)

Arrayas, Manuel; Trueba, Jose L; Baltanas, J P

2008-01-01

In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster

Fluctuation charge effects in ionization fronts

Energy Technology Data Exchange (ETDEWEB)

Arrayas, Manuel; Trueba, Jose L [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain); Baltanas, J P [Departamento de Fisica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

2008-05-21

In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster.

Post-Glacial Development of Western North Atlantic - Labrador Sea Oceanographic Circulation

DEFF Research Database (Denmark)

Sheldon, Christina

2015-01-01

The subpolar North Atlantic Ocean – Labrador Sea region is an important site for both oceanographic and atmospheric circulation. The convergence of ocean currents causes downwelling of cold, saline water in the subpolar gyre, helping to drive the world-wide thermohaline circulation system. The main......, the subpolar gyre weakened, which carried less Gulf Stream-derived water to the western North Atlantic Ocean via the West Greenland Current and the Slopewater Current, south of Newfoundland. Changes in the subpolar gyre circulation had developed to be analogous to the modern climate by approximately 2 cal kyr...... surface currents involved in the gyre are the south-flowing, cold and relatively fresh Labrador Current and the north-flowing, warm and relatively saline Gulf Stream. The oceanic front between these two major currents moves north and south, dependent on the relative strengths of the currents, impacting...

Light-Front Holography, Light-Front Wavefunctions, and Novel QCD Phenomena

DEFF Research Database (Denmark)

Brodsky, S. J.; de Teramond, G. F.

2012-01-01

Light-front holography is one of the most remarkable features of the AdS/CFT correspondence. In spite of its present limitations, it provides important physical insights into the non-perturbative regime of QCD and its transition to the perturbative domain. This novel framework allows hadronic...... projected on the free Fock basis provides the complete set of valence and non-valence light-front Fock state wavefunctions Psi(n)/H(x(i), k(perpendicular to i), lambda(i)) which describe the hadron's momentum and spin distributions needed to compute the direct measures of hadron structure at the quark...

HINS Linac front end focusing system R and D

International Nuclear Information System (INIS)

Apollinari, G.; Carcagno, R.H.; Dimarco, J.; Huang, Y.; Kashikhin, V.V.; Orris, D.F.; Page, T.M.; Rabehl, R.; Sylvester, C.; Tartaglia, M.A.; Terechkine, I.; Fermilab; Argonne

2008-01-01

This report summarizes current status of an R and D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process

Novel Perspectives from Light-Front QCD, Super-Conformal Algebra, and Light-Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-12-01

Light-Front Quantization – Dirac’s “Front Form” – provides a physical, frame-independent formalism for hadron dynamics and structure. Observables such as structure functions, transverse momentum distributions, and distribution amplitudes are defined from the hadronic LFWFs. One obtains new insights into the hadronic mass scale, the hadronic spectrum, and the functional form of the QCD running coupling in the nonperturbative domain using light-front holography. In addition, superconformal algebra leads to remarkable supersymmetric relations between mesons and baryons. I also discuss evidence that the antishadowing of nuclear structure functions is nonuniversal; i.e., flavor dependent, and why shadowing and antishadowing phenomena may be incompatible with the momentum and other sum rules for the nuclear parton distribution functions.

Self-Propagating Reactive Fronts in Compacts of Multilayered Particles

International Nuclear Information System (INIS)

Sraj, I.; Vohra, M.; Alawieh, L.; Weihs, T.P.; Knio, O.M.

2013-01-01

Reactive multilayered foils in the form of thin films have gained interest in various applications such as joining, welding, and ignition. Typically, thin film multilayers support self-propagating reaction fronts with speeds ranging from 1 to 20 m/s. In some applications, however, reaction fronts with much smaller velocities are required. This recently motivated Fritz et al. (2011) to fabricate compacts of regular sized/shaped multilayered particles and demonstrate self-sustained reaction fronts having much smaller velocities than thin films with similar layering. In this work, we develop a simplified numerical model to simulate the self-propagation of reactive fronts in an idealized compact, comprising identical Ni/Al multilayered particles in thermal contact. The evolution of the reaction in the compact is simulated using a two-dimensional transient model, based on a reduced description of mixing, heat release, and thermal transport. Computed results reveal that an advancing reaction front can be substantially delayed as it crosses from one particle to a neighboring particle, which results in a reduced mean propagation velocity. A quantitative analysis is thus conducted on the dependence of these phenomena on the contact area between the particles, the thermal contact resistance, and the arrangement of the multilayered particles.

Self-Propagating Reactive Fronts in Compacts of Multilayered Particles

Directory of Open Access Journals (Sweden)

Ihab Sraj

2013-01-01

Full Text Available Reactive multilayered foils in the form of thin films have gained interest in various applications such as joining, welding, and ignition. Typically, thin film multilayers support self-propagating reaction fronts with speeds ranging from 1 to 20 m/s. In some applications, however, reaction fronts with much smaller velocities are required. This recently motivated Fritz et al. (2011 to fabricate compacts of regular sized/shaped multilayered particles and demonstrate self-sustained reaction fronts having much smaller velocities than thin films with similar layering. In this work, we develop a simplified numerical model to simulate the self-propagation of reactive fronts in an idealized compact, comprising identical Ni/Al multilayered particles in thermal contact. The evolution of the reaction in the compact is simulated using a two-dimensional transient model, based on a reduced description of mixing, heat release, and thermal transport. Computed results reveal that an advancing reaction front can be substantially delayed as it crosses from one particle to a neighboring particle, which results in a reduced mean propagation velocity. A quantitative analysis is thus conducted on the dependence of these phenomena on the contact area between the particles, the thermal contact resistance, and the arrangement of the multilayered particles.

Oceanic hydraulic structures for developing a shelf. Issledovaniye morskikh gidrotekhnicheskikh sooruzheniy dlya osvoyenia sel'fa

Energy Technology Data Exchange (ETDEWEB)

Simakov, G.B.

1980-01-01

The anthology is devoted to practical problems of oceanic hydraulic engineering which arise during design and construction of specialized oceanic hydraulic structures to be erected and used in the shelf zones of seas and oceans. Most of the articles deal with studying the external effect of rough waters, impacts from ships and ice floes on floating and stationary hydraulic structures for developing a shelf. A great deal of attention is also given to the hydrodynamic and anchoring of floating hydraulic structures. The information reflects the current status of the problems of designing and building production facilities for developing a continental shelf.

Instability of an infiltration-driven dissolution-precipitation front with a nonmonotonic porosity profile

Science.gov (United States)

Kondratiuk, Paweł; Dutka, Filip; Szymczak, Piotr

2016-04-01

Infiltration of a rock by an external fluid very often drives it out of chemical equilibrium. As a result, alteration of the rock mineral composition occurs. It does not however proceed uniformly in the entire rock volume. Instead, one or more reaction fronts are formed, which are zones of increased chemical activity, separating the altered (product) rock from the yet unaltered (primary) one. The reaction fronts propagate with velocities which are usually much smaller than those of the infiltrating fluid. One of the simplest examples of such alteration is the dissolution of some of the minerals building the primary rock. For instance, calcium carbonate minerals in the rock matrix can be dissolved by infiltrating acidic fluids. In such a case the product rock has higher porosity and permeability than the primary one. Due to positive feedbacks between the reactant transport, fluid flow, and porosity generation, the reaction fronts in porosity-generating replacement systems are inherently unstable. An arbitrarily small protrusion of the front gets magnified and develops into a highly porous finger-like or funnel-like structure. This feature of dissolution fronts, dubbed the "reactive-infiltration instability" [1], is responsible for the formation of a number of geological patterns, such as solution pipes or various karst forms. It is also of practical importance, since spontaneous front breakup and development of localized highly porous flow paths (a.k.a. "wormholes") is favourable by petroleum engineers, who apply acidization to oil-bearing reservoirs in order to increase their permeability. However, more complex chemical reactions might occur during infiltration of a rock by a fluid. In principle, the products of dissolution might react with other species present either in the fluid or in the rock and reprecipitate [2]. The dissolution and precipitation fronts develop and and begin to propagate with equal velocities, forming a single dissolution-precipitation front

Control and Interlocking System for Bending Magnet Front-end at Indus-2

Science.gov (United States)

Kane, Sanjeev R.; Garg, Chander Kant; Nandedkar, R. V.

2007-01-01

We present control and interlock system developed for Indus-2 bending magnet front-end. The paper describes in detail the control of various signals associated with the front-end and the interlocking scheme implemented for the installed front-end. The number of signals associated with each front-end is ˜ 75. A control system is designed for monitoring temperature, pressure, airflow, water flow and control of vacuum gauges, fast shutter, water cooled shutter, safety shutter, pneumatic gate valves, sputter ion pump power supplies, beam position monitor etc. Two independent signals are generated for critical components that are used for software interlock and hard-wired interlock. The front-end control system is VME based and window 2000/XP workstation as an operator console. The CPU used is Motorola 68000-processor board of the VME bus having OS-9 real time operating system. One VME crate serves a cluster of 2-3 front ends. The communication between the VME and the workstation is linked over RS232 serial communication. The sputter ion power supplies are connected over isolated RS485 network. Critical protection features are implemented so that no single failure can render the system unsafe. This is implemented by providing two independent chains of protection (1) Hard wired in which relay logic is used and (2) Software. A Graphical User Interface (GUI) is developed using Lab view Version 7.0.

Control and Interlocking System for Bending Magnet Front-end at Indus-2

International Nuclear Information System (INIS)

Kane, Sanjeev R.; Garg, Chander Kant; Nandedkar, R. V.

2007-01-01

We present control and interlock system developed for Indus-2 bending magnet front-end. The paper describes in detail the control of various signals associated with the front-end and the interlocking scheme implemented for the installed front-end. The number of signals associated with each front-end is ∼ 75. A control system is designed for monitoring temperature, pressure, airflow, water flow and control of vacuum gauges, fast shutter, water cooled shutter, safety shutter, pneumatic gate valves, sputter ion pump power supplies, beam position monitor etc. Two independent signals are generated for critical components that are used for software interlock and hard-wired interlock. The front-end control system is VME based and window 2000/XP workstation as an operator console. The CPU used is Motorola 68000-processor board of the VME bus having OS-9 real time operating system. One VME crate serves a cluster of 2-3 front ends. The communication between the VME and the workstation is linked over RS232 serial communication. The sputter ion power supplies are connected over isolated RS485 network. Critical protection features are implemented so that no single failure can render the system unsafe. This is implemented by providing two independent chains of protection (1) Hard wired in which relay logic is used and (2) Software. A Graphical User Interface (GUI) is developed using Lab view Version 7.0

Numerical simulation of two-phase flow with front-capturing

International Nuclear Information System (INIS)

Tzanos, C.P.; Weber, D.P.

2000-01-01

Because of the complexity of two-phase flow phenomena, two-phase flow codes rely heavily on empirical correlations. This approach has a number of serious shortcomings. Advances in parallel computing and continuing improvements in computer speed and memory have stimulated the development of numerical simulation tools that rely less on empirical correlations and more on fundamental physics. The objective of this work is to take advantage of developments in massively parallel computing, single-phase computational fluid dynamics of complex systems, and numerical methods for front capturing in two-phase flows to develop a computer code for direct numerical simulation of two-phase flow. This includes bubble/droplet transport, interface deformation and topology change, bubble-droplet interactions, interface mass, momentum, and energy transfer. In this work, the Navier-Stokes and energy equations are solved by treating both phases as a single fluid with interfaces between the two phases, and a discontinuity in material properties across the moving interfaces. The evolution of the interfaces is simulated by using the front capturing technique of the level-set methods. In these methods, the boundary of a two-fluid interface is modeled as the zero level set of a smooth function φ. The level-set function φ is defined as the signed distance from the interface (φ is negative inside a droplet/bubble and positive outside). Compared to other front-capturing or front-tracking methods, the level-set approach is relatively easy to implement even in three-dimensional flows, and it has been shown to simulate well the coalescence and breakup of droplets/bubbles

Pteropods in Southern Ocean ecosystems

Science.gov (United States)

Hunt, B. P. V.; Pakhomov, E. A.; Hosie, G. W.; Siegel, V.; Ward, P.; Bernard, K.

2008-09-01

To date, little research has been carried out on pelagic gastropod molluscs (pteropods) in Southern Ocean ecosystems. However, recent predictions are that, due to acidification resulting from a business as usual approach to CO 2 emissions (IS92a), Southern Ocean surface waters may begin to become uninhabitable for aragonite shelled thecosome pteropods by 2050. To gain insight into the potential impact that this would have on Southern Ocean ecosystems, we have here synthesized available data on pteropod distributions and densities, assessed current knowledge of pteropod ecology, and highlighted knowledge gaps and directions for future research on this zooplankton group. Six species of pteropod are typical of the Southern Ocean south of the Sub-Tropical Convergence, including the four Thecosomes Limacina helicina antarctica, Limacina retroversa australis, Clio pyramidata, and Clio piatkowskii, and two Gymnosomes Clione limacina antarctica and Spongiobranchaea australis. Limacina retroversa australis dominated pteropod densities north of the Polar Front (PF), averaging 60 ind m -3 (max = 800 ind m -3) and 11% of total zooplankton at the Prince Edward Islands. South of the PF L. helicina antarctica predominated, averaging 165 ind m -3 (max = 2681 ind m -3) and up to >35% of total zooplankton at South Georgia, and up to 1397 ind m -3 and 63% of total zooplankton in the Ross Sea. Combined pteropods contributed 40% of community grazing impact. Further research is required to quantify diet selectivity, the effect of phytoplankton composition on growth and reproductive success, and the role of carnivory in thecosomes. Life histories are a significant knowledge gap for Southern Ocean pteropods, a single study having been completed for L. retroversa australis, making population studies a priority for this group. Pteropods appear to be important in biogeochemical cycling, thecosome shells contributing >50% to carbonate flux in the deep ocean south of the PF. Pteropods may also

Trace gas concentrations, intertropical convergence, atmospheric fronts, and ocean currents in the tropical Pacific m(Paper 8C1060)

International Nuclear Information System (INIS)

Wilkniss, P.E.; Rodgers, E.B.; Swinnerton, J.W.; Larson, R.E.; Lamontagne, R.A.

1979-01-01

Shipboard measurements of atmospheric 222 Rn, CO, and CH 4 and of dissolved CO in surface waters have been carried out in the equatorial Pacific on a cruise from Ecuador to Hawaii, Tahiti and Panama in March and April of 1974, and during transit from Los Angeles to Antarctica in November and December of 1972. The trace gas results, combined with conventional meteorological data and with satellite images from Nimbus 5 and the defense meteorological satellite project (DMSP), have provided descriptions of the intertropical convergence zones (ITCZ) near 04 0 N, 102 0 W and 03 0 N, 154 0 W in March of 1974, near 04 0 N, 86 0 W in April of 1974, and near 05 0 N, 139 0 W in November of 1972. In all cases the ITCZ seems to be located north of the south equatorial current (SEC) as shown by dissolved CO peaks in surface waters. In April of 1974 a 'second' ITCZ was observed near 01 0 S, 102 0 W just south of the SEC. A stationary front near Hawaii (20 0 N, 147 0 W) in March of 1974 was investigated. The ITCZ was marked by light shifting winds near a zone of heavy cloud cover and precipitation. In the eastern Tropical Pacific atmospheric 222 Rn increases distinctly north of the ITCZ and thus serves as an indicator for the ITCZ. CO and CH 4 do not always increase coincident with atmospheric 222 Rn. The atmospheric features of the stationary front near Hawaii are in many ways similar to those observed for the ITCZ. The front is marked by cloud cover, precipitation zone and light shifting winds. 222 Rn, CO and CH 4 increase signifantly behind the front in subsiding air which was traced back to the Asian continent. The variation of atmospheric 222 Rn, CO and CH 4 with time and geographical area over the equatorial Pacific seems to be a consequence of seasonal variations of the trade wind field and long range transport to the central Pacific from Asia and to the eastern equatorial Pacific from North and Central America

Development of front-end electronics for LumiCal detector in CMOS 130 nm technology

CERN Document Server

Firlej, M; Idzik, M; Moron, J; Swientek, K; Terlecki, P

2015-01-01

front-end electronics for luminosity detector at future Linear Collider are presented. The 8-channel prototype was designed and fabricated in a 130 nm CMOS technology. Each channel comprises a charge sensitive preamplifier with pole-zero cancellation circuit and a CR-RC shaper with 50 ns peaking time. The measurements results confirm full functionality of the prototype and compliance with the requirements imposed by the detector specification. The power consumption of the front-end is in the range 0.6–1.5 mW per channel and the noise ENC around 900 e− at 10 pF input capacitance.

Simulation of the sea breeze front with a model of moist convection

NARCIS (Netherlands)

Berg, L.C.J. van de; Oerlemans, J.

1985-01-01

Although in general the sea breeze can be considered as a mesoscale atmospheric circulation, the sea-breeze front has a much smaller scale. Simulation of the development of a sea-breeze front should therefore be preferably done with a non-hydrostatic model, with high spatial resolution (grid

Energy conversion at dipolarization fronts

Science.gov (United States)

Khotyaintsev, Yu. V.; Divin, A.; Vaivads, A.; André, M.; Markidis, S.

2017-02-01

We use multispacecraft observations by Cluster in the Earth's magnetotail and 3-D particle-in-cell simulations to investigate conversion of electromagnetic energy at the front of a fast plasma jet. We find that the major energy conversion is happening in the Earth (laboratory) frame, where the electromagnetic energy is being transferred from the electromagnetic field to particles. This process operates in a region with size of the order several ion inertial lengths across the jet front, and the primary contribution to E·j is coming from the motional electric field and the ion current. In the frame of the front we find fluctuating energy conversion with localized loads and generators at sub-ion scales which are primarily related to the lower hybrid drift instability excited at the front; however, these provide relatively small net energy conversion.

3He and chlorofluorocarbons (CFC) in the Southern Ocean

International Nuclear Information System (INIS)

Jean-Baptiste, P.; Jamous, D.; Mantisi, F.; Memery, L.; Universite Paris 6

1991-01-01

The distribution of 3 He across the Southern Ocean is depicted on the basis of a meridional section between Antarctica and South Africa measured during the INDIGO-3 survey (1988). A core of δ 3 He values above 10% is observed south of the Polar Front, associated with very low CFC concentrations. This 3 He enriched layer is documented from the GEOSECS and INDIGO 3 He data in the Southern Ocean. It is found at a density level around θ σ =27.8 in all the waters close to Antarctica (i.e. south of 50 degS). Its zonal distribution suggests that it is likely that it originates from the central/eastern Pacific. Hence, it provides an indication of the deep Pacific waters in the Antarctic Circumpolar Current, which are not easily detectable from the standard hydrographic parameters. (author). 19 refs.; 8 figs

Blocking-resistant communication through domain fronting

Directory of Open Access Journals (Sweden)

Fifield David

2015-06-01

Full Text Available We describe “domain fronting,” a versatile censorship circumvention technique that hides the remote endpoint of a communication. Domain fronting works at the application layer, using HTTPS, to communicate with a forbidden host while appearing to communicate with some other host, permitted by the censor. The key idea is the use of different domain names at different layers of communication. One domain appears on the “outside” of an HTTPS request—in the DNS request and TLS Server Name Indication—while another domain appears on the “inside”—in the HTTP Host header, invisible to the censor under HTTPS encryption. A censor, unable to distinguish fronted and nonfronted traffic to a domain, must choose between allowing circumvention traffic and blocking the domain entirely, which results in expensive collateral damage. Domain fronting is easy to deploy and use and does not require special cooperation by network intermediaries. We identify a number of hard-to-block web services, such as content delivery networks, that support domain-fronted connections and are useful for censorship circumvention. Domain fronting, in various forms, is now a circumvention workhorse. We describe several months of deployment experience in the Tor, Lantern, and Psiphon circumvention systems, whose domain-fronting transports now connect thousands of users daily and transfer many terabytes per month.

Temperature, salinity, oxygen, beam attenuation coefficient, and pressure measurements collected using CTD in the global ocean from 1990 to 1998 (NODC Accession 0002369)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — CTD and Transmissometer data from JGOFS Programs: Equatorial Pacific (EqPac), Antarctic Polar Front Zone (APFZ), North Atlantic Bloom Experiment (NABE), Arabian Sea...

Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals

Science.gov (United States)

Charrassin, J.-B.; Hindell, M.; Rintoul, S. R.; Roquet, F.; Sokolov, S.; Biuw, M.; Costa, D.; Boehme, L.; Lovell, P.; Coleman, R.; Timmermann, R.; Meijers, A.; Meredith, M.; Park, Y.-H.; Bailleul, F.; Goebel, M.; Tremblay, Y.; Bost, C.-A.; McMahon, C. R.; Field, I. C.; Fedak, M. A.; Guinet, C.

2008-01-01

Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals (Mirounga leonina) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice zone, allowing the major fronts to be mapped south of 60°S and sea-ice formation rates to be inferred from changes in upper ocean salinity. Sea-ice production rates peaked in early winter (April–May) during the rapid northward expansion of the pack ice and declined by a factor of 2 to 3 between May and August, in agreement with a three-dimensional coupled ocean–sea-ice model. By measuring the high-latitude ocean during winter, elephant seals fill a “blind spot” in our sampling coverage, enabling the establishment of a truly global ocean-observing system. PMID:18695241

General motors front wheel drive 2-mode hybrid transmission

Energy Technology Data Exchange (ETDEWEB)

Hendrickson, James [General Motors Corp., Pontiac, MI (United States). New Transmission Products Group.; Holmes, Alan G. [General Motors Corp., Pontiac, MI (United States). Powertrain Hybrid Architecture

2009-07-01

General Motors now expands the application of two-mode hybrid technology to front wheel drive vehicles with the development of a hybrid electric transmission packaged into essentially the same space as a conventional automatic transmission for front wheel drive. This was accomplished using a space-efficient arrangement based on two planetary gear sets and electric motor-generators with large internal diameters. A combination of damper and hydraulically-controlled clutch allow comfortable shutdown and restarting of large-displacement engines in front wheel drive vehicles. The hybrid system delivers electric low-speed urban driving, two continuously variable ranges of transmission speed ratios, four fixed transmission speed ratios, electric acceleration boosting, and regenerative braking. In the first vehicle application, the two-mode hybrid helps to reduce vehicle fuel consumption by approximately one-third. (orig.)

On the role of surface heat budget parameters over the tropical Indian Ocean in relation to the summer monsoon

Digital Repository Service at National Institute of Oceanography (India)

RameshKumar, M.R.; Sastry, J.S.

This study presents the role of sea surface temperature (SST) in the Arabian Sea and Bay of Bengal, cloud motion vector winds in the Equatorial Indian Ocean, and the cold fronts in the South Africa-Malagassy region on the onset and quantum...

Biogenic silica and organic carbon in sediments from the Pacific sector of the Southern Ocean

International Nuclear Information System (INIS)

Giglio, F.; Langone, L.; Morigi, C.; Frignani, M.; Ravaioli, M.

2002-01-01

Four cores, collected during the 1995/96 Italian Antarctic cruise and located north and south of the Polar Front, provided both qualitative and quantitative information about changes of the sediment settings driven by climate changes. Biogenic silica and organic carbon flux variations and sedimentological analyses allow us to make inferences about the fluctuation of the Polar Front during the last climate cycles: the records of our cores Anta96-1 and Anta96-16 account for fluctuations of the Polar Front of at least 5 degrees with respect to the present position, with a concomitant movement of the Marginal Ice Zone. The very low accumulation rates at the study sites are probably due to the scarce availability of micronutrients. In the area south of the Polar Front, sediment accumulation, after a decrease, appears constant during the last 250,000 yr. A subdivision in glacial/interglacial stages has been proposed, which permits the identification of the warm stage 11, which is particularly important in the Southern Ocean. (author). 13 refs., 5 figs

The Global Ocean Observing System (GOOS): New developments

International Nuclear Information System (INIS)

Summerhayes, C.P.

1999-01-01

GOOS will provide information about the present and future states of seas and oceans and their living resources, and on the role of the oceans in climate change. Among other things, it will include monitoring the extent to which the sea is polluted, and applying models enabling the behaviour of polluted environments to be forecast given a variety of forcing conditions including anthropogenic and natural changes. Implementation has begun through integration of previously separate existing observing systems into a GOOS Initial Observing System, and through the development of Pilot Projects, most notably in the coastal seas of Europe and North-east Asia. Although the present emphasis is on the measurement of physical properties, plans are underway for increasing the observation of chemical and biological parameters. The main biological thrust at present comes through the Global Coral Reef Monitoring Network (GCRMN). Consideration needs to be given to incorporation into the GOOS Initial Observing System of present national, international and global chemical and biological monitoring systems, and the development and implementation of new chemical and biological monitoring subsystems, especially in coastal seas for monitoring the health of those environments. GOOS will offer marine scientists and other users a scheme of continuing measurements on a scale larger in time and space than can be accomplished by individuals for their own applications, and a vastly improved store of basic marine environmental data for a multitude of purposes. For GOOS news see the GOOS Homepage at http://ioc.unesco.org/GOOS/. (author)

Hydrodynamic stability theory of double ablation front structures in inertial confinement fusion

International Nuclear Information System (INIS)

Yanez Vico, C.

2012-11-01

For moderate-Z materials, the hydrodynamic structure of the ablation region formed by the irradiation of high intensity laser beams differs from that of low-Z materials (hydrogenic ablators). In particular, the role played by the radiative energy flux becomes non-negligible for increasing atomic number material and ended up forming a second ablation front. This structure of two separated ablation fronts, called double ablation (DA) front, was confirmed in the simulations carried out by Fujioka et al. In this work a linear stability theory of DA fronts is developed for direct-drive inertial confinement fusion targets. Two models are proposed. First, a sharp boundary model where the thin front approximation is assumed for both ablation fronts. The information about the corona region that permits to close the sharp boundary model is obtained from a prior self-consistent analysis of the electronic-radiative ablation (ERA) front. Numerical results are presented as well as an analytical approach for the radiation dominated regime of very steep double ablation front structure. Second, a self-consistent numerical method where the finite length of the ablation fronts is considered. Accurate hydrodynamic profiles are taken into account in the theoretical model by means of a fitting parameters method using one-dimensional simulation results. Numerical dispersion relation is compared to the analytical sharp boundary model showing an excellent agreement for the radiation dominated regime, and the stabilization due to smooth profiles. 2D simulations are presented to validate the linear stability theory

Linear stability analysis of double ablation fronts in direct-drive inertial confinement fusion

International Nuclear Information System (INIS)

Yanez, C.; Sanz, J.; Ibanez, L. F.; Olazabal-Loume, M.

2011-01-01

A linear stability theory of double ablation fronts is developed for direct-drive inertial confinement fusion targets. The so-called electron radiative ablation front [S. Fujioka et al., Phys. Rev. Lett. 92, 195001 (2004)] is studied with a self-consistent model. Numerical results are presented as well as an analytical approach for the radiation dominated regime of very steep double ablation front structure. Dispersion relation formula is tackled by means of a sharp boundary model.

Temperature in subsonic and supersonic radiation fronts measured at OMEGA

Science.gov (United States)

Johns, Heather; Kline, John; Lanier, Nick; Perry, Ted; Fontes, Chris; Fryer, Chris; Brown, Colin; Morton, John

2017-10-01

Propagation of heat fronts relevant to astrophysical plasmas is challenging in the supersonic regime. Plasma Te changes affect opacity and equation of state without hydrodynamic change. In the subsonic phase density perturbations form at material interfaces as the plasma responds to radiation pressure of the front. Recent experiments at OMEGA studied this transition in aerogel foams driven by a hohlraum. In COAX, two orthogonal backlighters drive x-ray radiography and K-shell absorption spectroscopy to diagnose the subsonic shape of the front and supersonic Te profiles. Past experiments used absorption spectroscopy in chlorinated foams to measure the heat front; however, Cl dopant is not suitable for higher material temperatures at NIF. COAX has developed use of Sc and Ti dopants to diagnose Te between 60-100eV and 100-180eV. Analysis with PrismSPECT using OPLIB tabular opacity data will evaluate the platform's ability to advance radiation transport in this regime.

Improving client-centred care and services: the role of front/back-office configurations.

Science.gov (United States)

Broekhuis, Manda; de Blok, Carolien; Meijboom, Bert

2009-05-01

This paper is a report of a study conducted to explore the application of designing front- and back-office work resulting in efficient client-centred care in healthcare organizations that supply home care, welfare and domestic services. Front/back-office configurations reflect a neglected domain of design decisions in the development of more client-centred processes and structures without incurring major cost increases. Based on a literature search, a framework of four front/back-office configurations was constructed. To illustrate the usefulness of this framework, a single, longitudinal case study was performed in a large organization, which provides home care, welfare and domestic services for a sustained period (2005-2006). The case study illustrates how front/back-office design decisions are related to the complexity of the clients' demands and the strategic objectives of an organization. The constructed framework guides the practical development of front/back-office designs, and shows how each design contributes differently to such performance objectives as quality, speed and efficiency. The front/back-office configurations presented comprise an important first step in elaborating client-centred care and service provision to the operational level. It helps healthcare organizations to become more responsive and to provide efficient client-centred care and services when approaching demand in a well-tuned manner. In addition to its applicability in home care, we believe that a deliberate front/back-office configuration also has potential in other fields of health care.

Modeling beam-front dynamics at low gas pressures

International Nuclear Information System (INIS)

Briggs, R.J.; Yu, S.

1982-01-01

The dynamics of space charge neutralization at the front of an intense self-focused electron beam pulse exhibits important differences in different gas pressure regimes. At very low pressures, the beam front is in the so-called ion-focused regime (IFR) where all secondary electrons are expelled from the beam region by the radial electric field without causing significant additional ionization. We estimate the upper pressure boundary of this regime by considering the distance scale length for cascade (avalanche) ionization. Data from the FX-25 diode experiments indicate a critical transition pressure (P/sub c/) that agrees with this estimate and with its scaling among various gas types. Normal mobility-limited treatments (local conductivity models) of the secondary electrons at the beam front are not justified until the gas pressure is 10 to 50 times higher than P/sub c/, due to runaway of these secondary electrons in the strong space-charge electric field at the lower pressures. The main conclusion of this study is that a non-local phase space (Boltzmann) treatment of the secondary electrons is required to accurately describe these different beam front regimes and the transitions between them; such a code model is currently under development

Modeling hydrodynamic instabilities of double ablation fronts in inertial confinement fusion

International Nuclear Information System (INIS)

Yanez, C.; Sanz, J.; Olazabal-Loume, M.; Ibanez, L. F.

2013-01-01

A linear Rayleigh-Taylor instability theory of double ablation (DA) fronts is developed for direct-drive inertial confinement fusion. Two approaches are discussed: an analytical discontinuity model for the radiation dominated regime of very steep DA front structure, and a numerical self-consistent model that covers more general hydrodynamic profiles behaviours. Dispersion relation results are compared to 2D simulations. (authors)

Quaternary radiolarian faunal changes in the tropical Indian Ocean: Inferences to paleomonsoonal oscillation of the 10 degrees S hydrographic front

Digital Repository Service at National Institute of Oceanography (India)

Gupta, S.M.; Fernandes, A.A.

The northern Indian Ocean is characterized by three distinct surface water masses, i.e. (1) highly saline (greater than 34.5 ppt) Arabian Sea, (2) low saline (less than 34.5 ppt) Bay of Bengal and (3) a moderate salinity Indian Ocean watermass south...

Wave front sensing for next generation earth observation telescope

Science.gov (United States)

Delvit, J.-M.; Thiebaut, C.; Latry, C.; Blanchet, G.

2017-09-01

High resolution observations systems are highly dependent on optics quality and are usually designed to be nearly diffraction limited. Such a performance allows to set a Nyquist frequency closer to the cut off frequency, or equivalently to minimize the pupil diameter for a given ground sampling distance target. Up to now, defocus is the only aberration that is allowed to evolve slowly and that may be inflight corrected, using an open loop correction based upon ground estimation and refocusing command upload. For instance, Pleiades satellites defocus is assessed from star acquisitions and refocusing is done with a thermal actuation of the M2 mirror. Next generation systems under study at CNES should include active optics in order to allow evolving aberrations not only limited to defocus, due for instance to in orbit thermal variable conditions. Active optics relies on aberration estimations through an onboard Wave Front Sensor (WFS). One option is using a Shack Hartmann. The Shack-Hartmann wave-front sensor could be used on extended scenes (unknown landscapes). A wave-front computation algorithm should then be implemented on-board the satellite to provide the control loop wave-front error measure. In the worst case scenario, this measure should be computed before each image acquisition. A robust and fast shift estimation algorithm between Shack-Hartmann images is then needed to fulfill this last requirement. A fast gradient-based algorithm using optical flows with a Lucas-Kanade method has been studied and implemented on an electronic device developed by CNES. Measurement accuracy depends on the Wave Front Error (WFE), the landscape frequency content, the number of searched aberrations, the a priori knowledge of high order aberrations and the characteristics of the sensor. CNES has realized a full scale sensitivity analysis on the whole parameter set with our internally developed algorithm.

Development of a GUI Based Front End for Open Source CFD Program, OpenFOAM

International Nuclear Information System (INIS)

Han, Samhee; Lee, Youngjin; Kim, Hyongchol; Park, Sunbyung; Kim, Hyunjik

2013-01-01

OpenFOAM is sorely lacking in user friendliness as it runs in console mode under Li nux. Run F OAM was developed to greatly simplify the task of running an OpenFOAM calculation under Windows OS. Run F OAM was written using Delphi object pascal language, and GLScene package was used for the 3D graphics. Verification of Run F OAM was carried out by performing some OpenFOAM CFD calculations provided in OpenFOAM package, and these showed that the use of Run F OAM is simple whilst providing sufficient allowances in user modifications. Run F oam, a GUI based front end program to simplify running Open Foam CFD cases, has been developed. By incorporating numerous GUI in the program, Run F oam has demonstrated that running an Open Foam case can be easily accomplished. There is a potential for further development as the Open Foam has the great advantage of being free to develop and to use. There is also a potential to couple or interface the Open Foam with the systems analysis code such as Relap5

The first photon shutter development for APS insertion device beamline front ends

International Nuclear Information System (INIS)

Shu, Deming; Nian, H.L.T.; Wang, Zhibi; Collins, J.T.; Ryding, D.G.; Kuzay, T.M.

1992-01-01

One of the most critical components on the Advanced Photon Source (APS) insertion device (ID) beamline front ends is the first photon shutter. It operates in two modes to fully intercept the high total power and high-heat flux ID photon beam in seconds (normal mode) or in less than 100 ms (emergency fast mode). It is designed to operate in ultra high vacuum (UHV). The design incorporates a multi-channel rectangular bar, bent in a ''hockey stick'' configuration, with two-point suspension. The flanged end is an articulated bellows with rolling hinges. The actuation end is a spring-assisted, pneumatic fail-safe flexural pivot type. The coolant (water) channels incorporate brazed copper foam to enhance the heat transfer, a tube technology particular to the APS. The design development, and material aspects, as well as the extensive thermal and vibrational analyses in support of the design, are presented in this paper

Characterization and effects of cold fronts in the Colombian Caribbean Coast and their relationship to extreme wave events

Science.gov (United States)

Ortiz-Royero, J. C.; Otero, L. J.; Restrepo, J. C.; Ruiz, J.; Cadena, M.

2013-07-01

Extreme ocean waves in the Caribbean Sea are commonly related to the effects of storms and hurricanes during the months of June through November. The collapse of 200 m of the Puerto Colombia pier in March 2009 revealed the effects of meteorological phenomena other than storms and hurricanes that may be influencing the extreme wave regime in the Colombian Caribbean. The marked seasonality of these atmospheric fronts was established by analyzing the meteorological-marine reports of Instituto de Hidrología, Meteorología y Estudios Ambientales of Colombia (IDEAM, based on its initials in Spanish) and Centro de Investigación en Oceanografía y Meteorología of Colombia (CIOH, based on its initials in Spanish). The highest occurrences were observed during the months of January, February, and March, with 6 fronts occurring per year. An annual trend was not observed, although the highest number of fronts occurred in 2010 (20 in total). An annual strong relationship between the maximum average wave values and the cold fronts, in the central zone of the Colombian Caribbean during the first three months of the year was established. In addition, the maximum values of the significant height produced by the passage of cold fronts during the last 16 yr were identified. Although the Colombian Caribbean has been affected by storms and hurricanes in the past, this research allows us to conclude that, there is a strong relationship between cold fronts and the largest waves in the Colombian Caribbean during the last 16 yr, which have caused damage to coastal infrastructure. We verified that the passage of a cold front corresponded to the most significant extreme wave event of the last two decades in the Colombian Caribbean, which caused the structural collapse of the Puerto Colombia pier, located near the city of Barranquilla, between 5 and 10 March 2009. This information is invaluable when evaluating average and extreme wave regimes for the purpose of informing the design of

QCD and Light-Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.

2010-10-27

The soft-wall AdS/QCD model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics. The model predicts a zero-mass pion for zero-mass quarks and a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number N. Light-Front Holography maps the amplitudes which are functions of the fifth dimension variable z of anti-de Sitter space to a corresponding hadron theory quantized on the light front. The resulting Lorentz-invariant relativistic light-front wave equations are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. The result is to a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryon light-quark bound states, which in turn predict the behavior of the pion and nucleon form factors. The theory implements chiral symmetry in a novel way: the effects of chiral symmetry breaking increase as one goes toward large interquark separation, consistent with spectroscopic data, and the the hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. The soft-wall model also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q) and its {beta}-function which agrees with the effective coupling {alpha}{sub g1} extracted from the Bjorken sum rule. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also reviewed.

Oceanic archipelagos

DEFF Research Database (Denmark)

Triantis, Kostas A.; Whittaker, Robert James; Fernández-Palacios, José María

2016-01-01

Since the contributions of Charles Darwin and Alfred Russel Wallace, oceanic archipelagos have played a central role in the development of biogeography. However, despite the critical influence of oceanic islands on ecological and evolutionary theory, our focus has remained limited to either the i...... of the archipelagic geological dynamics that can affect diversity at both the island and the archipelagic level. We also reaffirm that oceanic archipelagos are appropriate spatiotemporal units to frame analyses in order to understand large scale patterns of biodiversity....

75 FR 54497 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

Science.gov (United States)

2010-09-08

.... SUMMARY: The EPA is designating the Guam Deep Ocean Disposal Site (G- DODS) as a permanent ocean dredged... administration of ocean disposal permits; (2) development and maintenance of a site monitoring program; (3... include: (1) Regulating quantities and types of material to be disposed, including the time, rates, and...

Atmosphere surface storm track response to resolved ocean mesoscale in two sets of global climate model experiments

Science.gov (United States)

Small, R. Justin; Msadek, Rym; Kwon, Young-Oh; Booth, James F.; Zarzycki, Colin

2018-05-01

It has been hypothesized that the ocean mesoscale (particularly ocean fronts) can affect the strength and location of the overlying extratropical atmospheric storm track. In this paper, we examine whether resolving ocean fronts in global climate models indeed leads to significant improvement in the simulated storm track, defined using low level meridional wind. Two main sets of experiments are used: (i) global climate model Community Earth System Model version 1 with non-eddy-resolving standard resolution or with ocean eddy-resolving resolution, and (ii) the same but with the GFDL Climate Model version 2. In case (i), it is found that higher ocean resolution leads to a reduction of a very warm sea surface temperature (SST) bias at the east coasts of the U.S. and Japan seen in standard resolution models. This in turn leads to a reduction of storm track strength near the coastlines, by up to 20%, and a better location of the storm track maxima, over the western boundary currents as observed. In case (ii), the change in absolute SST bias in these regions is less notable, and there are modest (10% or less) increases in surface storm track, and smaller changes in the free troposphere. In contrast, in the southern Indian Ocean, case (ii) shows most sensitivity to ocean resolution, and this coincides with a larger change in mean SST as ocean resolution is changed. Where the ocean resolution does make a difference, it consistently brings the storm track closer in appearance to that seen in ERA-Interim Reanalysis data. Overall, for the range of ocean model resolutions used here (1° versus 0.1°) we find that the differences in SST gradient have a small effect on the storm track strength whilst changes in absolute SST between experiments can have a larger effect. The latter affects the land-sea contrast, air-sea stability, surface latent heat flux, and the boundary layer baroclinicity in such a way as to reduce storm track activity adjacent to the western boundary in the N

Developing an Ontology for Ocean Biogeochemistry Data

Science.gov (United States)

Chandler, C. L.; Allison, M. D.; Groman, R. C.; West, P.; Zednik, S.; Maffei, A. R.

2010-12-01

Semantic Web technologies offer great promise for enabling new and better scientific research. However, significant challenges must be met before the promise of the Semantic Web can be realized for a discipline as diverse as oceanography. Evolving expectations for open access to research data combined with the complexity of global ecosystem science research themes present a significant challenge, and one that is best met through an informatics approach. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) is funded by the National Science Foundation Division of Ocean Sciences to work with ocean biogeochemistry researchers to improve access to data resulting from their respective programs. In an effort to improve data access, BCO-DMO staff members are collaborating with researchers from the Tetherless World Constellation (Rensselaer Polytechnic Institute) to develop an ontology that formally describes the concepts and relationships in the data managed by the BCO-DMO. The project required transforming a legacy system of human-readable, flat files of metadata to well-ordered controlled vocabularies to a fully developed ontology. To improve semantic interoperability, terms from the BCO-DMO controlled vocabularies are being mapped to controlled vocabulary terms adopted by other oceanographic data management organizations. While the entire process has proven to be difficult, time-consuming and labor-intensive, the work has been rewarding and is a necessary prerequisite for the eventual incorporation of Semantic Web tools. From the beginning of the project, development of the ontology has been guided by a use case based approach. The use cases were derived from data access related requests received from members of the research community served by the BCO-DMO. The resultant ontology satisfies the requirements of the use cases and reflects the information stored in the metadata database. The BCO-DMO metadata database currently contains information that

The emergence and evolution of the research fronts in HIV/AIDS research.

Directory of Open Access Journals (Sweden)

David Fajardo-Ortiz

Full Text Available In this paper, we have identified and analyzed the emergence, structure and dynamics of the paradigmatic research fronts that established the fundamentals of the biomedical knowledge on HIV/AIDS. A search of papers with the identifiers "HIV/AIDS", "Human Immunodeficiency Virus", "HIV-1" and "Acquired Immunodeficiency Syndrome" in the Web of Science (Thomson Reuters, was carried out. A citation network of those papers was constructed. Then, a sub-network of the papers with the highest number of inter-citations (with a minimal in-degree of 28 was selected to perform a combination of network clustering and text mining to identify the paradigmatic research fronts and analyze their dynamics. Thirteen research fronts were identified in this sub-network. The biggest and oldest front is related to the clinical knowledge on the disease in the patient. Nine of the fronts are related to the study of specific molecular structures and mechanisms and two of these fronts are related to the development of drugs. The rest of the fronts are related to the study of the disease at the cellular level. Interestingly, the emergence of these fronts occurred in successive "waves" over the time which suggest a transition in the paradigmatic focus. The emergence and evolution of the biomedical fronts in HIV/AIDS research is explained not just by the partition of the problem in elements and interactions leading to increasingly specialized communities, but also by changes in the technological context of this health problem and the dramatic changes in the epidemiological reality of HIV/AIDS that occurred between 1993 and 1995.

Differential sensor in front photopyroelectric technique: II. Experimental

International Nuclear Information System (INIS)

Ivanov, R; Moreno, I; Araujo-Andrade, C; MarIn, E; Cruz-Orea, A; Pichardo-Molina, J L

2009-01-01

We describe the differential cell design and the experimental (optical and electronic) setup for the differential front photopyroelectric technique, whose theory has been developed in the first part of this paper (Ivanov et al 2008 J. Phys. D: Appl. Phys. 41 085106). We will show first how the direct (non-differential) front photopyroelectric theory described in our previous paper reproduces well the experimental results. The usefulness of the differential technique is demonstrated by means of experimental measurements of the thermal effusivity in binary ethanol-water and glycerol-water mixtures, based on a theoretical methodology that simplifies the measurement procedure and diminishes the experimental uncertainty.

Differential sensor in front photopyroelectric technique: II. Experimental

Energy Technology Data Exchange (ETDEWEB)

Ivanov, R; Moreno, I; Araujo-Andrade, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, CP 98060, Zacatecas, Zac. (Mexico); MarIn, E [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada-Instituto Politecnico Nacional, Legaria 694, Col. Irrigacion, CP 11500, Mexico D.F. (Mexico); Cruz-Orea, A [Departamento de Fisica, CINVESTAV-IPN, Av. IPN No. 2508, Col. San Pedro Zacatenco, CP 07360, Mexico D.F. (Mexico); Pichardo-Molina, J L, E-mail: rumen@fisica.uaz.edu.m [Centro de Investigaciones en Optica, Loma del Bosque 115, Loma del Campestre, CP 37150, Leon, Guanajuato (Mexico)

2009-06-21

We describe the differential cell design and the experimental (optical and electronic) setup for the differential front photopyroelectric technique, whose theory has been developed in the first part of this paper (Ivanov et al 2008 J. Phys. D: Appl. Phys. 41 085106). We will show first how the direct (non-differential) front photopyroelectric theory described in our previous paper reproduces well the experimental results. The usefulness of the differential technique is demonstrated by means of experimental measurements of the thermal effusivity in binary ethanol-water and glycerol-water mixtures, based on a theoretical methodology that simplifies the measurement procedure and diminishes the experimental uncertainty.

Modeling study on nuclide transport in ocean - an ocean compartment method

International Nuclear Information System (INIS)

Lee, Youn Myoung; Suh, Kyung Suk; Han, Kyoung Won

1991-01-01

An ocean compartment model simulating transport of nuclides by advection due to ocean circulation and interaction with suspended sediments is developed, by which concentration breakthrough curves of nuclides can be calculated as a function of time. Dividing ocean into arbitrary number of characteristic compartments and performing a balance of mass of nuclides in each ocean compartment, the governing equation for the concentration in the ocean is obtained and a solution by the numerical integration is obtained. The integration method is specially useful for general stiff systems. For transfer coefficients describing advective transport between adjacent compartments by ocean circulation, the ocean turnover time is calculated by a two-dimensional numerical ocean method. To exemplify the compartment model, a reference case calculation for breakthrough curves of three nuclides in low-level radioactive wastes, Tc-99, Cs-137, and Pu-238 released from hypothetical repository under the seabed is carried out with five ocean compartments. Sensitivity analysis studies for some parameters to the concentration breakthrough curves are also made, which indicates that parameters such as ocean turnover time and ocean water volume of compartments have an important effect on the breakthrough curves. (Author)

Ocean Sciences Sequence for Grades 6-8: Climate Change Curriculum Developed Through a Collaboration Between Scientists and Educators

Science.gov (United States)

Halversen, C.; Weiss, E. L.; Pedemonte, S.

2016-02-01

Today's youth have been tasked with the overwhelming job of addressing the world's climate future. The students who will become the scientists, policy makers, and citizens of tomorrow must gain a robust understanding of the causes and effects of climate change, as well as possible adaptation strategies. Currently, few high quality curriculum materials exist that address climate change in a developmentally appropriate manner. The NOAA-funded Ocean Sciences Sequence for Grades 6-8: The Ocean-Atmosphere Connection and Climate Change (OSS) addresses this gap by providing teachers with scientifically accurate climate change curriculum that hits on some of the most salient points in climate science, while simultaneously developing students' science process skills. OSS was developed through a collaboration between some of the nation's leading ocean and climate scientists and the Lawrence Hall of Science's highly qualified curriculum development team. Scientists were active partners throughout the entire development process, from initial brainstorming of key concepts and creating the conceptual storyline for the curriculum to final review of the content and activities. The goal was to focus strategically and effectively on core concepts within ocean and climate sciences that students should understand. OSS was designed in accordance with the latest research from the learning sciences and provides numerous opportunities for students to develop facility with science practices by "doing" science.Through hands-on activities, technology, informational readings, and embedded assessments, OSS deeply addresses a significant number of standards from the Next Generation Science Standards and is being used by many teachers as they explore the shifts required by NGSS. It also aligns with the Ocean Literacy and Climate Literacy Frameworks. OSS comprises 33 45-minute sessions organized into three thematic units, each driven by an exploratory question: (1) How do the ocean and atmosphere

Proceedings of international workshop on utilization of nuclear power in oceans (N'ocean 2000)

International Nuclear Information System (INIS)

Yamaji, A.; Nariyama, N.; Sawada, K.

2000-03-01

Human beings and the ocean have maintained close relations for a long time. The ocean produced the life at very old time and human beings have been benefited by ocean, particularly in Japan that is surrounded by the ocean. In the utilization of nuclear power in ocean, Japan has been very active from the beginning of the development of nuclear power. The nuclear powered ship MUTSU has been developed and completed the experimental voyage. Besides the nuclear powered ship, we are using the ocean for the transportation of radioactive materials. This International Workshop aimed at offering further information about nuclear utilization in oceans such as icebreakers, deep-sea submarines, high speed carriers, floating plant, desalination and heating plants, radioactive materials transport ships, and so on. The discussions on the economical, environmental and scientific effects are included. The 36 of the present papers are indexed individually. (J.P.N.)

Oceanic Precondition and Evolution of the Indian Ocean Dipole Events

Science.gov (United States)

Horii, T.; Masumoto, Y.; Ueki, I.; Hase, H.; Mizuno, K.

2008-12-01

Indian Ocean Dipole (IOD) is one of the interannual climate variability in the Indian Ocean, associated with the negative (positive) SST anomaly in the eastern (western) equatorial region developing during boreal summer/autumn seasons. Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has been deploying TRITON buoys in the eastern equatorial Indian Ocean since October 2001. Details of subsurface ocean conditions associated with IOD events were observed by the mooring buoys in the eastern equatorial Indian Ocean in 2006, 2007, and 2008. In the 2006 IOD event, large-scale sea surface signals in the tropical Indian Ocean associated with the positive IOD started in August 2006, and the anomalous conditions continued until December 2006. Data from the mooring buoys, however, captured the first appearance of the negative temperature anomaly at the thermocline depth with strong westward current anomalies in May 2006, about three months earlier than the development of the surface signatures. Similar appearance of negative temperature anomalies in the subsurface were also observed in 2007 and 2008, while the amplitude, the timing, and the relation to the surface layer were different among the events. The implications of the subsurface conditions for the occurrences of these IOD events are discussed.

COMBINED EFFECTS OF OCEAN ACIDIFICATION, OCEAN WARMING AND OIL SPILL ON ASPECTS OF DEVELOPMENT OF MARINE INVERTEBRATES

OpenAIRE

Arnberg, maj

2016-01-01

Full version unavailable due to 3rd party copyright restrictions. For decades, humans have impacted marine ecosystems in a variety of ways including contamination by pollution, fishing, and physical destruction of habitats. Global change has, and will, lead to alterations in in a number of abiotic factors of our ocean in particular reduced oxygen saturation, salinity changes, elevated temperature (ocean warming or OW) and elevated carbon dioxide (ocean acidification or OA). Now and in the...

Light-Front Quantization of Gauge Theories

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.

2003-03-25

Light-front wavefunctions provide a frame-independent representation of hadrons in terms of their physical quark and gluon degrees of freedom. The light-front Hamiltonian formalism provides new nonperturbative methods for obtaining the QCD spectrum and eigensolutions, including resolvant methods, variational techniques, and discretized light-front quantization. A new method for quantizing gauge theories in light-cone gauge using Dirac brackets to implement constraints is presented. In the case of the electroweak theory, this method of light-front quantization leads to a unitary and renormalizable theory of massive gauge particles, automatically incorporating the Lorentz and 't Hooft conditions as well as the Goldstone boson equivalence theorem. Spontaneous symmetry breaking is represented by the appearance of zero modes of the Higgs field leaving the light-front vacuum equal to the perturbative vacuum. I also discuss an ''event amplitude generator'' for automatically computing renormalized amplitudes in perturbation theory. The importance of final-state interactions for the interpretation of diffraction, shadowing, and single-spin asymmetries in inclusive reactions such as deep inelastic lepton-hadron scattering is emphasized.

Light-Front Quantization of Gauge Theories

Energy Technology Data Exchange (ETDEWEB)

Brodskey, Stanley

2002-12-01

Light-front wavefunctions provide a frame-independent representation of hadrons in terms of their physical quark and gluon degrees of freedom. The light-front Hamiltonian formalism provides new nonperturbative methods for obtaining the QCD spectrum and eigensolutions, including resolvant methods, variational techniques, and discretized light-front quantization. A new method for quantizing gauge theories in light-cone gauge using Dirac brackets to implement constraints is presented. In the case of the electroweak theory, this method of light-front quantization leads to a unitary and renormalizable theory of massive gauge particles, automatically incorporating the Lorentz and 't Hooft conditions as well as the Goldstone boson equivalence theorem. Spontaneous symmetry breaking is represented by the appearance of zero modes of the Higgs field leaving the light-front vacuum equal to the perturbative vacuum. I also discuss an ''event amplitude generator'' for automatically computing renormalized amplitudes in perturbation theory. The importance of final-state interactions for the interpretation of diffraction, shadowing, and single-spin asymmetries in inclusive reactions such as deep inelastic lepton-hadron scattering is emphasized.

Positional Velar Fronting: An Updated Articulatory Account

Science.gov (United States)

Byun, Tara McAllister

2012-01-01

This study develops the hypothesis that the child-specific phenomenon of positional velar fronting can be modeled as the product of phonologically encoded articulatory limitations unique to immature speakers. Children have difficulty executing discrete tongue movements, preferring to move the tongue and jaw as a single unit. This predisposes the…

Localized structures and front propagation in the Lengyel-Epstein model

DEFF Research Database (Denmark)

Jensen, O.; Pannbacker, Viggo Ole; Mosekilde, Erik

1994-01-01

Pattern selection, localized structure formation, and front propagation are analyzed within the framework of a model for the chlorine dioxide-iodine-malonic acid reaction that represents a key to understanding recently obtained Turing structures. This model is distinguished from previously studied......, simple reaction-diffusion models by producing a strongly subcritical transition to stripes. The wave number for the modes of maximum linear gain is calculated and compared with the dominant wave number for the finally selected, stationary structures grown from the homogeneous steady state or developed...... bifurcation. In the subcritical regime there is an interval where the front velocity vanishes as a result of a pinning of the front to the underlying structure. In 2D, two different nucleation mechanisms for hexagonal structures are illustrated on the Lengyel-Epstein and the Brusselator model. Finally...

Developments in Coastal Ocean Modeling

Science.gov (United States)

Allen, J. S.

2001-12-01

Capabilities in modeling continental shelf flow fields have improved markedly in the last several years. Progress is being made toward the long term scientific goal of utilizing numerical circulation models to interpolate, or extrapolate, necessarily limited field measurements to provide additional full-field information describing the behavior of, and providing dynamical rationalizations for, complex observed coastal flow. The improvement in modeling capabilities has been due to several factors including an increase in computer power and, importantly, an increase in experience of modelers in formulating relevant numerical experiments and in analyzing model results. We demonstrate present modeling capabilities and limitations by discussion of results from recent studies of shelf circulation off Oregon and northern California (joint work with Newberger, Gan, Oke, Pullen, and Wijesekera). Strong interactions between wind-forced coastal currents and continental shelf topography characterize the flow regimes in these cases. Favorable comparisons of model and measured alongshore currents and other variables provide confidence in the model-produced fields. The dependence of the mesoscale circulation, including upwelling and downwelling fronts and flow instabilities, on the submodel used to parameterize the effects of small scale turbulence, is discussed. Analyses of model results to provide explanations for the observed, but previously unexplained, alongshore variability in the intensity of coastal upwelling, which typically results in colder surface water south of capes, and the observed development in some locations of northward currents near the coast in response to the relaxation of southward winds, are presented.

Analog front end circuit design of CSNS beam loss monitor system

International Nuclear Information System (INIS)

Xiao Shuai; Guo Xian; Tian Jianmin; Zeng Lei; Xu Taoguang; Fu Shinian

2013-01-01

The China Spallation Neutron Source (CSNS) beam loss monitor system uses gas ionization chamber to detect beam losses. The output signals from ionization chamber need to be processed in the analog front end circuit, which has been designed and developed independently. The way of transimpedance amplifier was used to achieve current-voltage (I-V) conversion measurement of signal with low repetition rate, low duty cycle and low amplitude. The analog front end circuit also realized rapid response to the larger beam loss in order to protect the safe operation of the accelerator equipment. The testing results show that the analog front end circuit meets the requirements of beam loss monitor system. (authors)

An important role of the moisture supply from the Kuroshio Current/Kuroshio Extension in the rapid development of an explosive cyclone

Science.gov (United States)

Hirata, H.; Kawamura, R.; Kato, M.; Shinoda, T.

2014-12-01

We investigated how the moisture supply from the Kuroshio Current/Kuroshio Extension affects the rapid intensification of an explosive cyclone using a couple atmosphere-ocean non-hydrostatic model, CReSS-NHOES. The Cloud-Resolving Storm Simulator (CReSS) and the Non-Hydrostatic Ocean model for the Earth Simulator (NHOES) have been developed by the Hydrospheric Atmospheric Research Center of Nagoya University and the Japan Agency for Marine-Earth Science and Technology, respectively. We performed a numerical simulation of an extratropical cyclone migrating along the southern periphery of the Kuroshio Current on January 14, 2013, that developed most rapidly in recent years in the vicinity of Japan. The evolutions of surface fronts related to the cyclone simulated by the CReSS-NHOES closely resemble Shapiro-Keyser model. In the lower troposphere, the cyclone's bent-back front and the associated frontal T-bone structure become evident with the cyclone development. Cold Conveyor Belt (CCB) is also well organized over the northern part of the cyclone. During its developing stage, since the CCB dominates just over the Kuroshio Current/Kuroshio Extension, a large amount of moisture is efficiently supplied from the warm current into the CCB. The vapor evaporated from the underlying warm current is transported into the bent-back front by the CCB and converges horizontally in the vicinity of the front. As a result, strong diabatic heating arises over the corresponding moisture convergence area in that vicinity, indicating that the abundant moisture due to the warm current plays a vital role in rapid development of the cyclone through latent heat release processes. Both processes of the moisture transport from the warm current into the cyclone system via the CCB and of the latent heat release around the bent-back front are also confirmed by trajectory analyses. The rapid SLP decrease of the cyclone center can in turn increase the moisture supply from the warm current through

Coastal Ocean Ecosystem Dynamics Imager Pointing Line-of-Sight Solution Development and Testing

Data.gov (United States)

National Aeronautics and Space Administration — A stable pointing line of sight solution is developed and tested in support of the Coastal Ocean Ecosystem Dynamics Imager for the GEOstationary Coastal and Air...

Cephalopods of the Southwest Indian OceanRidge: A hotspot of biological diversity and absence of endemism

Science.gov (United States)

Laptikhovsky, V.; Boersch-Supan, P.; Bolstad, K.; Kemp, K.; Letessier, T.; Rogers, A. D.

2017-02-01

A total of 68 cephalopod species belonging to 26 families (10-11% of the total known cephalopod diversity) were collected onboard R/V Fridtjof Nansen during a research survey on Southwest Indian Ocean Ridge in November-December 2009. This relatively small area extends from the Tropical front to the Subantarctic front with four distinctive cephalopod faunas and represents one of the most outstanding hotspots of cephalopod diversity reported to date. However, most of the species caught there were characterised by circumglobal distribution in the Southern Hemisphere, and no endemic species were unambiguously found, although a number of taxa could not be confidently attributed to known species. Most of the studied area was dominated by squid species reproducing in epipelagic layers (mostly Enoploteuthidae and Pyroteuthidae). Species reproducing in meso-bathypelagial whose juveniles ascend to surface water (Cranchiidae, Histioteuthidae, etc.) became gradually more and more important southward from the Tropical Zone to the Southern Peripheral Ecotone. In the latter region they were joined by near-bottom dwellers of the order Sepiolida. The epipelagic strategy of reproduction disappears completely at the Subpolar Front, where epipelagic waters were inhabited by young members of the Cranchiidae and Gonatidae hatched in deep-seas. This study demonstrated the importance of conservation and management of this high-seas area, with its unique biodiversity and ecological resources, in line with recommendations by the IUCN Seamount project and Global Ocean Biodiversity Initiative.

Light front quantum chromodynamics: Towards phenomenology

Indian Academy of Sciences (India)

Light front dynamics; quantum chromodynamics; deep inelastic scattering. PACS Nos 11.10. ... What makes light front dynamics appealing from high energy phenomenology point of view? .... given in terms of Poincarй generators by. MВ = W P ...

Validation and Inter-comparison Against Observations of GODAE Ocean View Ocean Prediction Systems

Science.gov (United States)

Xu, J.; Davidson, F. J. M.; Smith, G. C.; Lu, Y.; Hernandez, F.; Regnier, C.; Drevillon, M.; Ryan, A.; Martin, M.; Spindler, T. D.; Brassington, G. B.; Oke, P. R.

2016-02-01

For weather forecasts, validation of forecast performance is done at the end user level as well as by the meteorological forecast centers. In the development of Ocean Prediction Capacity, the same level of care for ocean forecast performance and validation is needed. Herein we present results from a validation against observations of 6 Global Ocean Forecast Systems under the GODAE OceanView International Collaboration Network. These systems include the Global Ocean Ice Forecast System (GIOPS) developed by the Government of Canada, two systems PSY3 and PSY4 from the French Mercator-Ocean Ocean Forecasting Group, the FOAM system from UK met office, HYCOM-RTOFS from NOAA/NCEP/NWA of USA, and the Australian Bluelink-OceanMAPS system from the CSIRO, the Australian Meteorological Bureau and the Australian Navy.The observation data used in the comparison are sea surface temperature, sub-surface temperature, sub-surface salinity, sea level anomaly, and sea ice total concentration data. Results of the inter-comparison demonstrate forecast performance limits, strengths and weaknesses of each of the six systems. This work establishes validation protocols and routines by which all new prediction systems developed under the CONCEPTS Collaborative Network will be benchmarked prior to approval for operations. This includes anticipated delivery of CONCEPTS regional prediction systems over the next two years including a pan Canadian 1/12th degree resolution ice ocean prediction system and limited area 1/36th degree resolution prediction systems. The validation approach of comparing forecasts to observations at the time and location of the observation is called Class 4 metrics. It has been adopted by major international ocean prediction centers, and will be recommended to JCOMM-WMO as routine validation approach for operational oceanography worldwide.

Report on the value engineering workshop on APS beamline front ends

International Nuclear Information System (INIS)

Kuzay, T.

1993-01-01

A formal value engineering evaluation process was developed to address the front end components of the beamlines for the Advanced Photon Source (APS). This process (described in Section 2) involved an information phase, a creative phase, a judgment phase, a development phase, and a recommendation phase. Technical experts from other national laboratories and industry were invited to a two-day Value Engineering Workshop on November 5-6, 1992. The results of this Workshop are described in Section 4. Following the Workshop, various actions by the APS staff led to the redesign of the front end components, which are presented in Sections 5 and 6. The cost benefit analysis is presented in Section 7. It is important of realize that an added benefit of the Workshop was to obtain numerous design evaluations and enhancements of the front end components by experts in the field. As the design work proceeds to Title II completion, the APS staff is including many of these suggestions

The Aquarius Ocean Salinity Mission High Stability L-band Radiometer

Science.gov (United States)

Pellerano, Fernando A.; Piepmeier, Jeffrey; Triesky, Michael; Horgan, Kevin; Forgione, Joshua; Caldwell, James; Wilson, William J.; Yueh, Simon; Spencer, Michael; McWatters, Dalia;

Front Propagation in Stochastic Neural Fields

KAUST Repository

Bressloff, Paul C.; Webber, Matthew A.

2012-01-01

We analyze the effects of extrinsic multiplicative noise on front propagation in a scalar neural field with excitatory connections. Using a separation of time scales, we represent the fluctuating front in terms of a diffusive-like displacement

From the front lines to the home front: a history of the development of psychiatric nursing in the U.S. during the World War II era.

Science.gov (United States)

Silverstein, Christine M

2008-07-01

During World War II, psychiatric nurses learned valuable lessons on how to deal with the traumas of war. Using psychohistorical inquiry, this historian examined primary and secondary sources, beyond the facts and dates associated with historical events, to understand why and how psychiatric nurse pioneers developed therapeutic techniques to address the psychosocial and physical needs of combatants. Not only is the story told about the hardships endured as nurses ministered to soldiers, but their attitudes, beliefs, and emotions, that is, how they felt and what they thought about their circumstances, are explored. In this study the lived experiences of two psychiatric nurses, Votta and Peplau, are contrasted to explicate how knowledge development improved care and how this knowledge had an impact on the home front in nursing practice and education, as well as in mental institutions and society, long after the war was won.

Developing a global ocean observing system that prioritises ecosystem variables from a political and societal point of view

Science.gov (United States)

Miloslavich, P.; Bax, N. J.; Simmons, S. E.; Appeltans, W.; Garcia, M.

2016-02-01

The Biology and Ecosystems Panel of GOOS aims to develop and coordinate efforts to implement a sustained and targeted global ocean observation system. This system will be driven by societal needs (including the Sustainable Development Goals), and identify Essential Ocean Variables (EOVs) to inform priority scientific and societal questions that will facilitate critical policy development and management decision-making on ocean and coastal resource sustainability and health. Mature EOVs need to have global relevance and the capacity for global measurement. Our goal is to implement at least one (set of) mature EOVs by 2019, and identify a further three (sets of) pilot EOVs with a clear pathway to maturity. Our initial work includes (1) identifying drivers and pressures of societal and scientific needs, and (2) identifying internationally agreed goals that need sustained global observations of ocean biological & ecosystem variables for a healthy ocean. We reviewed 24 major conventions/international organizations (including the CBD and 16 UN related) to identify the societal needs these organizations address through their goals, and to produce a set of overlapping objectives. Main drivers identified in these conventions were: knowledge (science/data access), development (sustainable economic growth), conservation (biodiversity & ecosystems), sustainable use (biodiversity & resources), environmental quality (health), capacity building (technology transfer), food security, threat prevention and impact mitigation (to different pressures) and improved management (integrated ecosystem approach). The main pressures identified were climate change, ocean acidification, extreme weather events, overfishing/ overexploitation, pollution/ eutrophication, mining, solid wastes. Our next step will be to develop consensus with the observing community about the EOVs that will meet these needs and support the expansion of these identified EOVs into successful global observing systems.

Ocean Data Interoperability Platform (ODIP): developing a common framework for marine data management on a global scale

Science.gov (United States)

Schaap, Dick M. A.; Glaves, Helen

2016-04-01

Europe, the USA, and Australia are making significant progress in facilitating the discovery, access and long term stewardship of ocean and marine data through the development, implementation, population and operation of national, regional or international distributed ocean and marine observing and data management infrastructures such as SeaDataNet, EMODnet, IOOS, R2R, and IMOS. All of these developments are resulting in the development of standards and services implemented and used by their regional communities. The Ocean Data Interoperability Platform (ODIP) project is supported by the EU FP7 Research Infrastructures programme, National Science Foundation (USA) and Australian government and has been initiated 1st October 2012. Recently the project has been continued as ODIP II for another 3 years with EU HORIZON 2020 funding. ODIP includes all the major organisations engaged in ocean data management in EU, US, and Australia. ODIP is also supported by the IOC-IODE, closely linking this activity with its Ocean Data Portal (ODP) and Ocean Data Standards Best Practices (ODSBP) projects. The ODIP platform aims to ease interoperability between the regional marine data management infrastructures. Therefore it facilitates an organised dialogue between the key infrastructure representatives by means of publishing best practice, organising a series of international workshops and fostering the development of common standards and interoperability solutions. These are evaluated and tested by means of prototype projects. The presentation will give further background on the ODIP projects and the latest information on the progress of three prototype projects addressing: 1. establishing interoperability between the regional EU, USA and Australia data discovery and access services (SeaDataNet CDI, US NODC, and IMOS MCP) and contributing to the global GEOSS and IODE-ODP portals; 2. establishing interoperability between cruise summary reporting systems in Europe, the USA and

Development of a GUI Based Front End for Open Source CFD Program, OpenFOAM

Energy Technology Data Exchange (ETDEWEB)

Han, Samhee; Lee, Youngjin; Kim, Hyongchol; Park, Sunbyung; Kim, Hyunjik [Nuclear Safety Evaluation, Daejeon (Korea, Republic of)

2013-05-15

OpenFOAM is sorely lacking in user friendliness as it runs in console mode under Li nux. Run{sub F}OAM was developed to greatly simplify the task of running an OpenFOAM calculation under Windows OS. Run{sub F}OAM was written using Delphi object pascal language, and GLScene package was used for the 3D graphics. Verification of Run{sub F}OAM was carried out by performing some OpenFOAM CFD calculations provided in OpenFOAM package, and these showed that the use of Run{sub F}OAM is simple whilst providing sufficient allowances in user modifications. Run{sub F}oam, a GUI based front end program to simplify running Open Foam CFD cases, has been developed. By incorporating numerous GUI in the program, Run{sub F}oam has demonstrated that running an Open Foam case can be easily accomplished. There is a potential for further development as the Open Foam has the great advantage of being free to develop and to use. There is also a potential to couple or interface the Open Foam with the systems analysis code such as Relap5.

Asymptotic analysis of reaction-diffusion-advection problems: Fronts with periodic motion and blow-up

Science.gov (United States)

Nefedov, Nikolay

2017-02-01

This is an extended variant of the paper presented at MURPHYS-HSFS 2016 conference in Barcelona. We discuss further development of the asymptotic method of differential inequalities to investigate existence and stability of sharp internal layers (fronts) for nonlinear singularly perturbed periodic parabolic problems and initial boundary value problems with blow-up of fronts for reaction-diffusion-advection equations. In particular, we consider periodic solutions with internal layer in the case of balanced reaction. For the initial boundary value problems we prove the existence of fronts and give their asymptotic approximation including the new case of blowing-up fronts. This case we illustrate by the generalised Burgers equation.

MMIC front-ends for optical communication systems

DEFF Research Database (Denmark)

Petersen, Anders Kongstad

1993-01-01

Two different types of optical front-end MMIC amplifiers for a 2.5-Gb/s coherent heterodyne optical receiver are presented. A bandwidth of 6-12 GHz has been obtained for a tuned front-end and 3-13 GHz for a distributed front-end. An input noise current density of 5-15 pA/√Hz has been obtained for...

Application of up-front licensing

Energy Technology Data Exchange (ETDEWEB)

Grant, S D [Atomic Energy of Canada Ltd., Saskatoon, SK (Canada); Snell, V G [Atomic Energy of Canada Ltd., Mississauga, ON (Canada)

1996-12-31

AECL has been pioneering `up-front` licensing of new reactor designs. The CANDU 3 design has been formally reviewed by AECB staff for a number of years. The CANDU 9 design has just started the up-front licensing process. The process gives designers, regulators and potential customers early confidence in the licensability of future plants. (author). 4 refs., 2 tabs.

Application of up-front licensing

International Nuclear Information System (INIS)

Grant, S.D.; Snell, V.G.

1995-01-01

AECL has been pioneering 'up-front' licensing of new reactor designs. The CANDU 3 design has been formally reviewed by AECB staff for a number of years. The CANDU 9 design has just started the up-front licensing process. The process gives designers, regulators and potential customers early confidence in the licensability of future plants. (author). 4 refs., 2 tabs

Wintertime sea surface temperature fronts in the Taiwan Strait

Science.gov (United States)

Chang, Yi; Shimada, Teruhisa; Lee, Ming-An; Lu, Hsueh-Jung; Sakaida, Futoki; Kawamura, Hiroshi

2006-12-01

We present wintertime variations and distributions of sea surface temperature (SST) fronts in the Taiwan Strait by applying an entropy-based edge detection method to 10-year (1996-2005) satellite SST images with grid size of 0.01°. From climatological monthly mean maps of SST gradient magnitude in winter, we identify four significant SST fronts in the Taiwan Strait. The Mainland China Coastal Front is a long frontal band along the 50-m isobath near the Chinese coast. The sharp Peng-Chang Front appears along the Peng-Hu Channel and extends northward around the Chang-Yuen Ridge. The Taiwan Bank Front evolves in early winter. As the winter progresses, the front becomes broad and moves toward the Chinese coast, connecting to the Mainland China Coastal Front. The Kuroshio Front extends northeastward from the northeastern tip of Taiwan with a semicircle-shape curving along the 100-m isobath.

77 FR 15052 - National Ocean Council-National Ocean Policy Draft Implementation Plan

Science.gov (United States)

2012-03-14

... charge for Federal agencies to implement the National Ocean Policy, the National Ocean Council developed... dollars a year to the national economy, and are essential to public health and national security. Next...

NeXOS, developing and evaluating a new generation of insitu ocean observation systems.

Science.gov (United States)

Delory, Eric; del Rio, Joaquin; Golmen, Lars; Roar Hareide, Nils; Pearlman, Jay; Rolin, Jean-Francois; Waldmann, Christoph; Zielinski, Oliver

2017-04-01

Ocean biological, chemical or physical processes occur over widely varying scales in space and time: from micro- to kilometer scales, from less than seconds to centuries. While space systems supply important data and information, insitu data is necessary for comprehensive modeling and forecasting of ocean dynamics. Yet, collection of in-situ observation on these scales is inherently challenging and remains generally difficult and costly in time and resources. This paper address the innovations and significant developments for a new generation of insitu sensors in FP7 European Union project "Next generation, Cost- effective, Compact, Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management" or "NeXOS" for short. Optical and acoustics sensors are the focus of NeXOS but NeXOS moves beyond just sensors as systems that simultaneously address multiple objectives and applications are becoming increasingly important. Thus NeXOS takes a perspective of both sensors and sensor systems with significant advantages over existing observing capabilities via the implementation of innovations such as multiplatform integration, greater reliability through better antifouling management and greater sensor and data interoperability through use of OGC standards. This presentation will address the sensor system development and field-testing of the new NeXOS sensor systems. This is being done on multiple platforms including profiling floats, gliders, ships, buoys and subsea stations. The implementation of a data system based on SWE and PUCK furthers interoperability across measurements and platforms. This presentation will review the sensor system capabilities, the status of field tests and recommendations for long-term ocean monitoring.

Ocean Sciences Sequence for Grades 6-8: Climate Change Curriculum Developed Through a Collaboration Between Scientists and Educators

Science.gov (United States)

Weiss, E.; Skene, J.; Tran, L.

2011-12-01

Today's youth have been tasked with the overwhelming job of addressing the world's climate future. The students who will become the scientists, policy makers, and citizens of tomorrow must gain a robust understanding of the causes and effects of climate change, as well as possible adaptation strategies. Currently, there are few high quality curricula available to teachers that address these topics in a developmentally appropriate manner. The NOAA-funded Ocean Sciences Sequence for Grades 6-8 aims to address this gap by providing teachers with scientifically accurate climate change curriculum that hits on some of the most salient points in climate science, while simultaneously developing students' science process skills. The Ocean Sciences Sequence for Grades 6-8 is developed through a collaboration between some of the nation's leading ocean and climate scientists and the Lawrence Hall of Science's highly qualified GEMS (Great Explorations in Math & Science) curriculum development team. Scientists are active partners throughout the whole development process, from initial brainstorming of key concepts and creating the conceptual storyline for the curriculum to final review of the content and activities. As with all GEMS Sequences, the Ocean Sciences Sequence for Grades 6-8 is designed to provide significant scientific and educational depth, systematic assessments and informational readings, and incorporate new learning technologies. The goal is to focus strategically and effectively on the core concepts within ocean and climate sciences that students need to understand. This curriculum is designed in accordance with the latest research from the learning sciences, and provides numerous opportunities for students to develop inquiry skills and abilities as they learn about the practice of science through hands-on activities. The Ocean Sciences Sequence for Grades 6-8 addresses in depth a significant number of national, state, and district standards and benchmarks. It

Overturn of the Oceasn Flow in the North Atlantic as a Trigger of Inertia Motion to Form a Meridional Ocean Circulation

Science.gov (United States)

Nakamura, Shigehisa

2010-05-01

This work is an introduction of a meridional ocean circulation. As for the zonal motions,there have been many contributions. Recent oceanographic works noticed an overturn of the ocean current in the North Atlantic. The author notices this overturn is a trigger to generate a meridional ocean circulation to have a track through the deep Atlantic, the deep circum-polar current, the deep branch flow to the Pacific between the Australian and the South America. The east part of the branch flow relates to the upwelling off Peru, and the west part relates to form a deep water in the Northwest Pacific. THe overturn of the North Atlantic suggests an outflow of the deep water and a storage of the old aged deep water in the Northwest Pacific. The storage water increase in the Northwest Pacific shoould be a trigger of the swelling up of the sea level mid Pacific to affect to the ocean front variations between the coastal waters and the ocean water. In order to keep a hydrodynamic balance on the earth, an increase of the deep water in the Pacific should flow through the Bering Sea and the Arctic Sea to get to the North Atlantic. It should be noted that a budget of the ocean water flow must be hold the condition of the water masses concservation on the earth surface. This inertia motion is maintained once induced after any natural effect or some man-made influences. At this stage, the author has to notice that there has been developed a meridional inertia path of the air particle as well as the ocean water parcel, nevertheless nobody has had pointed out this inertiamotion with a meridional path in the ocean. Air-sea interaction must be one of the main factors for driving the ocean water though the inertia motion in the global scale is more energetic. To the details, the scientists should pursue what geophysical dynamics must be developed in the future.

Beam-front dynamics and ion acceleration in drifting intense relativistic electron beams

International Nuclear Information System (INIS)

Alexander, K.F.; Hintze, W.

1976-01-01

Collective ion acceleration at the injection of a relativistic electron beam into a low-pressure gas or a plasma is discussed and its strong dependence on the beam-front dynamics is shown. A simple one-dimensional model taking explicitly into account the motion and ionizing action of the ions in the beam-front region is developed for the calculation of the beam drift velocity. The obtained pressure dependence is in good agreement with experimental data. The energy distribution is shown of the ions accelerated in the moving potential well of the space charge region. Scaling laws for the beam-front dynamics and ion acceleration are derived. (J.U.)

Characterizing Ion Flows Across a Dipolarization Front

Science.gov (United States)

Arnold, H.; Drake, J. F.; Swisdak, M.

2017-12-01

In light of the Magnetospheric Multiscale Mission (MMS) moving to study predominately symmetric magnetic reconnection in the Earth's magnetotail, it is of interest to investigate various methods for determining the relative location of the satellites with respect to the x line or a dipolarization front. We use a 2.5 dimensional PIC simulation to explore the dependence of various characteristics of a front, or flux bundle, on the width of the front in the dawn-dusk direction. In particular, we characterize the ion flow in the x-GSM direction across the front. We find a linear relationship between the width of a front, w, and the maximum velocity of the ion flow in the x-GSM direction, Vxi, for small widths: Vxi/VA=w/di*1/2*(mVA2)/Ti*Bz/Bxwhere m, VA, di, Ti, Bz, and Bx are the ion mass, upstream Alfven speed, ion inertial length, ion temperature, and magnetic fields in the z-GSM and x-GSM directions respectively. However, once the width reaches around 5 di, the relationship gradually approaches the well-known theoretical limit for ion flows, the upstream Alfven speed. Furthermore, we note that there is a reversal in the Hall magnetic field near the current sheet on the positive y-GSM side of the front. This reversal is most likely due to conservation of momentum in the y-GSM direction as the ions accelerate towards the x-GSM direction. This indicates that while the ions are primarily energized in the x-GSM direction by the front, they transfer energy to the electromagnetic fields in the y-GSM direction. The former energy transfer is greater than the latter, but the reversal of the Hall magnetic field drags the frozen-in electrons along with it outside of the front. These simulations should better able researchers to determine the relative location of a satellite crossing a dipolarization front.

Implementation of a gust front head collapse scheme in the WRF numerical model

Science.gov (United States)

Lompar, Miloš; Ćurić, Mladjen; Romanic, Djordje

2018-05-01

measurement. Similar to the ideal case, WRF model with the gust front scheme gave more precipitation than the default WRF run. In particular, the gust front scheme increased the area characterized with light precipitation and diminished the development of very localized and intense precipitation.

Terrorism and Politics Predominate on the Front Pages of the Basque Press. Content and Area Analysis of the Front Pages of the Regional Newspapers

Directory of Open Access Journals (Sweden)

Dr. Jesús A. Pérez Dasilva

2010-01-01

Full Text Available This paper offers the results of research project 08/20 of the University of the Basque Country on the news published on the front pages of the Basque press during the years 1996, 2001 and 2006.The researchers analyse the front pages of the Basque press to determine if their content matches the demand and interests of their readers. The study shows what are the most relevant topics for these newspapers. The research involved a detailed analysis of 2,448 front pages of the five main Basque newspapers, with a total of 19,156 news items. A specific methodology was developed for this work, enabling both a quantitative and qualitative analysis of the news stories to be made. The data shown in this paper are a summary of the more detailed results that emerged in the different fields of the research.

Syntactic and FSP Aspects of Fronting as a Style Marker

Directory of Open Access Journals (Sweden)

Libuše Dušková

2017-07-01

Full Text Available The paper examines contextual and emphatic fronting in academic prose, fiction narrative and fiction dialogue in order to ascertain whether the types of fronting can serve as a style marker. The differences in the distribution and their effect on style are assumed to be connected with the respective FSP structures: in emphatic fronting the fronted element is the rheme, whereas in contextual fronting it is the diatheme. Hence emphatic fronting displays a prominent deviation from the basic distribution of communicative dynamism, whereas contextual fronting achieves agreement with it. As compared with the unmarked postverbal ordering, emphatic fronting intensifies the emphatic/emotional character of the content being expressed, which is a feature of speech, while contextual fronting serves as a direct link with what precedes, hence contributes to textual cohesion, which is a characteristic of academic prose, with fiction narrative presumably occupying an intermediate position. The results of the study show more types of fronting with diversified structures and less clear-cut relations between the types of frontings and the examined text sorts.

Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere oceans

Science.gov (United States)

Bostock, H. C.; Mikaloff Fletcher, S. E.; Williams, M. J. M.

2013-10-01

Using ocean carbon data from global datasets, we have developed several multiple linear regression (MLR) algorithms to estimate alkalinity and dissolved inorganic carbon (DIC) in the intermediate and deep waters of the Southern Hemisphere (south of 25° S) from only hydrographic data (temperature, salinity and dissolved oxygen). A Monte Carlo experiment was used to identify a potential density (σθ) of 27.5 as an optimal break point between the two regimes with different MLR algorithms. The algorithms provide a good estimate of DIC (R2=0.98) and alkalinity (R2=0.91), and excellent agreement for aragonite and calcite saturation states (R2=0.99). Combining the algorithms with the CSIRO Atlas of Regional Seas (CARS), we have mapped the calcite saturation horizon (CSH) and aragonite saturation horizon (ASH) for the Southern Ocean at a spatial resolution of 0.5°. These maps are more detailed and more consistent with the oceanography than the previously gridded GLODAP data. The high-resolution ASH map reveals a dramatic circumpolar shoaling at the polar front. North of 40° S the CSH is deepest in the Atlantic (~ 4000 m) and shallower in the Pacific Ocean (~ 2750 m), while the CSH sits between 3200 and 3400 m in the Indian Ocean. The uptake of anthropogenic carbon by the ocean will alter the relationships between DIC and hydrographic data in the intermediate and deep waters over time. Thus continued sampling will be required, and the MLR algorithms will need to be adjusted in the future to account for these changes.

Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere oceans

Directory of Open Access Journals (Sweden)

H. C. Bostock

2013-10-01

Full Text Available Using ocean carbon data from global datasets, we have developed several multiple linear regression (MLR algorithms to estimate alkalinity and dissolved inorganic carbon (DIC in the intermediate and deep waters of the Southern Hemisphere (south of 25° S from only hydrographic data (temperature, salinity and dissolved oxygen. A Monte Carlo experiment was used to identify a potential density (σθ of 27.5 as an optimal break point between the two regimes with different MLR algorithms. The algorithms provide a good estimate of DIC (R2=0.98 and alkalinity (R2=0.91, and excellent agreement for aragonite and calcite saturation states (R2=0.99. Combining the algorithms with the CSIRO Atlas of Regional Seas (CARS, we have mapped the calcite saturation horizon (CSH and aragonite saturation horizon (ASH for the Southern Ocean at a spatial resolution of 0.5°. These maps are more detailed and more consistent with the oceanography than the previously gridded GLODAP data. The high-resolution ASH map reveals a dramatic circumpolar shoaling at the polar front. North of 40° S the CSH is deepest in the Atlantic (~ 4000 m and shallower in the Pacific Ocean (~ 2750 m, while the CSH sits between 3200 and 3400 m in the Indian Ocean. The uptake of anthropogenic carbon by the ocean will alter the relationships between DIC and hydrographic data in the intermediate and deep waters over time. Thus continued sampling will be required, and the MLR algorithms will need to be adjusted in the future to account for these changes.

An Explorative Note on Tourism Development along Former War Front Lines

Directory of Open Access Journals (Sweden)

Myriam Jansen-Verbeke

2016-11-01

Full Text Available Current research about the pro-active role of tourism in valorizing war memories and landscapes still is in an explorative stage; learning from case studies, all marked by their political context, in time and space, and mainly describing local and/or regional key issues. Obviously, creating landscapes of memories for contemporary uses and visitors’ experiences implies a trans-disciplinary understanding of the process of changing values (heritage landscapes and of the intrinsic dynamics of tourism development. Shifting values and creativity in linking histories of war sites and their narratives with places and people today, leads to branding ‘sites of memories’ in the mindset of residents and visitors.We briefly scan four very different examples of border areas with a war history, that became landmarks on the tourist’ maps today.  The challenge for tourism development in former war related sites is to identify the dynamics - in time and space - to assess the political and economic forces and to identify shifts in the process of remembrance and valorization of war heritage sites, in terms of interests in war memories, narratives and experiences. These are now strategically integrated in national, regional and local tourism development planning.Historical military front zones, political borders in past wars, presently marked as tourism destinations, are on the research agenda of ‘War and Tourism’.  The observations below on four different former  war border zones with their specific landmarks and memoryscapes, are inspiring for current tourism development. Four different war border zones were briefly  explored “The Great Wall in China” “The Roman Limes”, The “Wire of Death”  in the  First World War  and the ”Iron Curtain” in the Cold War. These observations can inspire future research on tourismification of war heritage.

Light-front QCD. II. Two-component theory

International Nuclear Information System (INIS)

Zhang, W.; Harindranath, A.

1993-01-01

The light-front gauge A a + =0 is known to be a convenient gauge in practical QCD calculations for short-distance behavior, but there are persistent concerns about its use because of its ''singular'' nature. The study of nonperturbative field theory quantizing on a light-front plane for hadronic bound states requires one to gain a priori systematic control of such gauge singularities. In the second paper of this series we study the two-component old-fashioned perturbation theory and various severe infrared divergences occurring in old-fashioned light-front Hamiltonian calculations for QCD. We also analyze the ultraviolet divergences associated with a large transverse momentum and examine three currently used regulators: an explicit transverse cutoff, transverse dimensional regularization, and a global cutoff. We discuss possible difficulties caused by the light-front gauge singularity in the applications of light-front QCD to both old-fashioned perturbative calculations for short-distance physics and upcoming nonperturbative investigations for hadronic bound states

Control of a laser front wave

International Nuclear Information System (INIS)

Akaoka, K.; Wakaida, I.

1996-01-01

We controlled the laser wave front through a laser beam simulation experiment propagating through medium. Thus, we confirmed that the RMS, defined as the quadratic mean of the laser beam wave front, dropped to the 1/3 - 1/6 of the pre-control value

Utilizing a Novel Approach at the Fuzzy Front-End of New Product Development: A Case Study in a Flexible Fabric Supercapacitor

Directory of Open Access Journals (Sweden)

Gwo-Tsuen Jou

2016-08-01

Full Text Available The fuzzy front-end plays a most crucial part in new product development (NPD, leading to the success of product development and product launch in the market. This study proposes a novel method, TTRI_MP, by combining Crawford and Di Benedetto’s model and Cooper’s model, to strengthen the management of the fuzzy front-end. The proposed method comprises four stages: market exploration and technology forecasting, idea generation and segmentation, portfolio analysis and technology roadmapping (TRM. In the first stage, SWOT was utilized to identify the key strategic areas, and the technology readiness level (TRL was adopted to position the level of developed technologies. In the second stage, the business concepts were required to go through the viability test and customers, collaborators, competitors and company (4C. In the third stage, the Strategic Position Analysis (SPAN and Financial Analysis (FAN developed by IBM were employed in the portfolio analysis to screen out potential NPD projects. In the last stage, the selected NPD projects were linked with their functions and technologies in the TRM chart. The method was successfully implemented by a research team working on a flexible fabric supercapacitor at the Taiwan Textile Research Institute (TTRI.

Fast front-end electronics for COMPASS MWPCs

CERN Document Server

Colantoni, M L; Ferrero, A; Frolov, V; Grasso, A; Heinz, S; Maggiora, A; Maggiora, M G; Panzieri, D; Popov, A; Tchalyshev, V

2000-01-01

In the COMPASS experiment, under construction at CERN, about 23000 channels of MWPCs will be used. The very high rate of the muon and hadron beams, and the consequently high trigger rate, require front- end electronics with innovative conceptual design. A new MWPC front- end electronics that fulfills the main COMPASS requirement to have a fast DAQ with a minimum dead-time has been designed. The general concept of the front-end cards is described; the comparative tests of two front-end chips, and different fast gas mixtures, are also shown. The commissioning of the experiment will start in the summer 2000, and production running, using the muon beam, is foreseen for the year 2001. (8 refs).

Ocean acidification postcards

Science.gov (United States)

Schreppel, Heather A.; Cimitile, Matthew J.

2011-01-01

The U.S. Geological Survey (USGS) is conducting research on ocean acidification in polar, temperate, subtropical, and tropical regions including the Arctic, West Florida Shelf, and the Caribbean. Project activities include field assessment, experimental laboratory studies, and evaluation of existing data. The USGS is participating in international and interagency working groups to develop research strategies to increase understanding of the global implications of ocean acidification. Research strategies include new approaches for seawater chemistry observation and modeling, assessment of physiological effects on organisms, changes in marine ecosystem structure, new technologies, and information resources. These postcards highlight ongoing USGS research efforts in ocean acidification and carbon cycling in marine and coastal ecosystems in three different regions: polar, temperate, and tropical. To learn more about ocean acidification visit: http://coastal.er.usgs.gov/ocean-acidification/.

Development and validation of a 64 channel front end ASIC for 3D directional detection for MIMAC

International Nuclear Information System (INIS)

Richer, J P; Bourrion, O; Bosson, G; Guillaudin, O; Mayet, F; Santos, D

2011-01-01

A front end ASIC has been designed to equip the μTPC prototype developed for the MIMAC project, which requires 3D reconstruction of low energy particle tracks in order to perform directional detection of galactic Dark Matter. Each ASIC is able to monitor 64 strips of pixels and provides the 'Time Over Threshold' information for each of those. These 64 digital informations, sampled at a rate of 50 MHz, can be transferred at 400 MHz by eight LVDS serial links. Eight ASIC were validated on a 2 × 256 strips of pixels prototype.

Systematic Approach to Formulate PSS Development Project Proposals in the Fuzzy Front End

DEFF Research Database (Denmark)

Barquet, Ana Paula B.; Pigosso, Daniela Cristina Antelmi; Rozenfeld, Henrique

2013-01-01

be considered by companies during this definition. The systematization of PSS attributes may help increase the knowledge about different PSS projects that can emerge in the front end, thus leading to the discovery of opportunities that are not apparent in the existing business models and give rise to new ideas...

Nitrogen uptake by phytoplankton in surface waters of the Indian sector of Southern Ocean during austral summer

Science.gov (United States)

Tripathy, S. C.; Patra, Sivaji; Vishnu Vardhan, K.; Sarkar, A.; Mishra, R. K.; Anilkumar, N.

2018-03-01

This study reports the nitrogen uptake rate (using 15N tracer) of phytoplankton in surface waters of different frontal zones in the Indian sector of the Southern Ocean (SO) during austral summer of 2013. The investigated area encompasses four major frontal systems, i.e., the subtropical front (STF), subantarctic front (SAF), polar front-1 (PF1) and polar front-2 (PF2). Southward decrease of surface water temperature was observed, whereas surface salinity did not show any significant trend. Nutrient (NO3 - and SiO4 4-) concentrations increased southward from STF to PF; while ammonium (NH4 +), nitrite (NO2 -) and phosphate (PO4 3-) remained comparatively stable. Analysis of nutrient ratios indicated potential N-limited conditions at the STF and SAF but no such scenario was observed for PF. In terms of phytoplankton biomass, PF1 was found to be the most productive followed by SAF, whereas PF2 was the least productive region. Nitrate uptake rate increased with increasing latitude, as no systematic spatial variation was discerned for NH4 + and urea (CO(NH2)2). Linear relationship between nitrate and total N-uptake reveals that the studied area is capable of exporting up to 60% of the total production to the deep ocean if the environmental settings are favorable. Like N-uptake rates the f-ratio also increased towards PF region indicating comparatively higher new production in the PF than in the subtropics. The moderately high average f-ratio (0.53) indicates potentially near equal contributions by new production and regenerated production to the total productivity in the study area. Elevation in N-uptake rates with declining temperature suggests that the SO with its vast quantity of cool water could play an important role in drawing down the atmospheric CO2 through the "solubility pump".

Zero modes in discretized light-front quantization

International Nuclear Information System (INIS)

Martinovic, E.

1997-01-01

The current understanding of the role of bosonic zero modes in field-theoretical models quantized at the equal light-front time is reviewed. After a brief discussion of the main features of the light-front field theories - in particular the simplicity of the physical vacuum - the light-front canonical formalism for the quantum electrodynamics and the Yukawa model is sketched. The zero mode of Maskawa and Yamawaki is reviewed. Reasons for the appearance of the constrained and/or dynamical zero modes are explained along with the subtleties of the gauge fixing in presence of boundary conditions. Perturbative treatment of the corresponding constraint equations in the Yukawa model and quantum electrodynamics (3+1) is outlined. The next topic is the manifestation of the symmetry breaking in the light-front field theory. A pattern of multiple solutions to the zero-mode constraint equations replacing physical picture of multiple vacua of the conventionally quantized field theories is illustrated on an example of 2-dimensional theory. The importance of a (regularized) constrained zero mode of the pion field for the consistency of the Nambu-Goldstone phase of the discretized light-front linear a/model is demonstrated. Finally, a non-trivial physical vacuum based on the dynamical zero mode is constructed for the two-dimensional light-front quantum electrodynamics. (authors)

Adaptive two-regime method: Application to front propagation

Energy Technology Data Exchange (ETDEWEB)

Robinson, Martin, E-mail: martin.robinson@maths.ox.ac.uk; Erban, Radek, E-mail: erban@maths.ox.ac.uk [Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG (United Kingdom); Flegg, Mark, E-mail: mark.flegg@monash.edu [School of Mathematical Sciences, Faculty of Science, Monash University Wellington Road, Clayton, Victoria 3800 (Australia)

2014-03-28

The Adaptive Two-Regime Method (ATRM) is developed for hybrid (multiscale) stochastic simulation of reaction-diffusion problems. It efficiently couples detailed Brownian dynamics simulations with coarser lattice-based models. The ATRM is a generalization of the previously developed Two-Regime Method [Flegg et al., J. R. Soc., Interface 9, 859 (2012)] to multiscale problems which require a dynamic selection of regions where detailed Brownian dynamics simulation is used. Typical applications include a front propagation or spatio-temporal oscillations. In this paper, the ATRM is used for an in-depth study of front propagation in a stochastic reaction-diffusion system which has its mean-field model given in terms of the Fisher equation [R. Fisher, Ann. Eugen. 7, 355 (1937)]. It exhibits a travelling reaction front which is sensitive to stochastic fluctuations at the leading edge of the wavefront. Previous studies into stochastic effects on the Fisher wave propagation speed have focused on lattice-based models, but there has been limited progress using off-lattice (Brownian dynamics) models, which suffer due to their high computational cost, particularly at the high molecular numbers that are necessary to approach the Fisher mean-field model. By modelling only the wavefront itself with the off-lattice model, it is shown that the ATRM leads to the same Fisher wave results as purely off-lattice models, but at a fraction of the computational cost. The error analysis of the ATRM is also presented for a morphogen gradient model.

Supersymmetric Properties of Hadron Physics from Light-Front Holography and Superconformal Algebra and other Advances in Light-Front QCD

Science.gov (United States)

Brodsky, Stanley J.

2018-05-01

Light-front holography, together with superconformal algebra, have provided new insights into the physics of color confinement and the spectroscopy and dynamics of hadrons. As shown by de Alfaro, Fubini and Furlan, a mass scale can appear in the equations of motion without affecting the conformal invariance of the action if one adds a term to the Hamiltonian proportional to the dilatation operator or the special conformal operator. If one applies the procedure of de Alfaro et al. to the frame-independent light-front Hamiltonian, it leads uniquely to a confining q \\bar{q} potential κ ^4 ζ ^2, where ζ ^2 is the light-front radial variable related in momentum space to the q \\bar{q} invariant mass. The same result, including spin terms, is obtained using light-front holography—the duality between the front form and AdS_5, the space of isometries of the conformal group—if one modifies the action of AdS_5 by the dilaton e^{κ ^2 z^2} in the fifth dimension z. When one generalizes this procedure using superconformal algebra, the resulting light-front eigensolutions lead to a a unified Regge spectroscopy of meson, baryon, and tetraquarks, including supersymmetric relations between their masses and their wavefunctions. One also predicts hadronic light-front wavefunctions and observables such as structure functions, transverse momentum distributions, and the distribution amplitudes. The mass scale κ underlying confinement and hadron masses can be connected to the parameter Λ_{\\overline{MS}} in the QCD running coupling by matching the nonperturbative dynamics to the perturbative QCD regime. The result is an effective coupling α _s(Q^2) defined at all momenta. The matching of the high and low momentum transfer regimes determines a scale Q_0 which sets the interface between perturbative and nonperturbative hadron dynamics. I also discuss a number of applications of light-front phenomenology.

Muon front end for the neutrino factory

CERN Document Server

Rogers, C T; Prior, G; Gilardoni, S; Neuffer, D; Snopok, P; Alekou, A; Pasternak, J

2013-01-01

In the neutrino factory, muons are produced by firing high-energy protons onto a target to produce pions. The pions decay to muons and pass through a capture channel known as the muon front end, before acceleration to 12.6 GeV. The muon front end comprises a variable frequency rf system for longitudinal capture and an ionization cooling channel. In this paper we detail recent improvements in the design of the muon front end.

Development of a dedicated front-end electronics for straw tube trackers in the bar PANDA experiment

Science.gov (United States)

Przyborowski, D.; Fiutowski, T.; Idzik, M.; Kajetanowicz, M.; Korcyl, G.; Salabura, P.; Smyrski, J.; Strzempek, P.; Swientek, K.; Terlecki, P.; Tokarz, J.

2016-08-01

The design and tests of front-end electronics for straw tube trackers in the bar PANDA experiment at FAIR are presented. The challenges for the front-end electronics, comprising operation at high counting rate up to 1 MHz per straw tube, are discussed and the proposed architecture comprising a switched gain charge sensitive preamplifier (CSP), a pole-zero cancellation circuit (PZC), a second order variable peaking time shaper, a trimming ion tail cancellation circuit, and a baseline holder (BLH), is described. The front-end provides an analogue output and a discriminator with LVDS differential driver for the Time-of-Arrival (ToA) and Time-over-Threshold (ToT) measurements. A prototype readout ASIC featuring four channels was fabricated in 0.35 μm CMOS technology consuming 15.5 mW (analog part) and 12 mW (LVDS) per channel. The results of measurements of peaking time (25-67 ns), gain, noise (ENC 800-2500 el. for various gains), time walk and jitter are presented as well as the first results obtained with prototype straw tubes connected.

Effects of ocean initial perturbation on developing phase of ENSO in a coupled seasonal prediction model

Science.gov (United States)

Lee, Hyun-Chul; Kumar, Arun; Wang, Wanqiu

2018-03-01

Coupled prediction systems for seasonal and inter-annual variability in the tropical Pacific are initialized from ocean analyses. In ocean initial states, small scale perturbations are inevitably smoothed or distorted by the observational limits and data assimilation procedures, which tends to induce potential ocean initial errors for the El Nino-Southern Oscillation (ENSO) prediction. Here, the evolution and effects of ocean initial errors from the small scale perturbation on the developing phase of ENSO are investigated by an ensemble of coupled model predictions. Results show that the ocean initial errors at the thermocline in the western tropical Pacific grow rapidly to project on the first mode of equatorial Kelvin wave and propagate to the east along the thermocline. In boreal spring when the surface buoyancy flux weakens in the eastern tropical Pacific, the subsurface errors influence sea surface temperature variability and would account for the seasonal dependence of prediction skill in the NINO3 region. It is concluded that the ENSO prediction in the eastern tropical Pacific after boreal spring can be improved by increasing the observational accuracy of subsurface ocean initial states in the western tropical Pacific.

OceanNOMADS: Real-time and retrospective access to operational U.S. ocean prediction products

Science.gov (United States)

Harding, J. M.; Cross, S. L.; Bub, F.; Ji, M.

2011-12-01

The National Oceanic and Atmospheric Administration (NOAA) National Operational Model Archive and Distribution System (NOMADS) provides both real-time and archived atmospheric model output from servers at the National Centers for Environmental Prediction (NCEP) and National Climatic Data Center (NCDC) respectively (http://nomads.ncep.noaa.gov/txt_descriptions/marRutledge-1.pdf). The NOAA National Ocean Data Center (NODC) with NCEP is developing a complementary capability called OceanNOMADS for operational ocean prediction models. An NCEP ftp server currently provides real-time ocean forecast output (http://www.opc.ncep.noaa.gov/newNCOM/NCOM_currents.shtml) with retrospective access through NODC. A joint effort between the Northern Gulf Institute (NGI; a NOAA Cooperative Institute) and the NOAA National Coastal Data Development Center (NCDDC; a division of NODC) created the developmental version of the retrospective OceanNOMADS capability (http://www.northerngulfinstitute.org/edac/ocean_nomads.php) under the NGI Ecosystem Data Assembly Center (EDAC) project (http://www.northerngulfinstitute.org/edac/). Complementary funding support for the developmental OceanNOMADS from U.S. Integrated Ocean Observing System (IOOS) through the Southeastern University Research Association (SURA) Model Testbed (http://testbed.sura.org/) this past year provided NODC the analogue that facilitated the creation of an NCDDC production version of OceanNOMADS (http://www.ncddc.noaa.gov/ocean-nomads/). Access tool development and storage of initial archival data sets occur on the NGI/NCDDC developmental servers with transition to NODC/NCCDC production servers as the model archives mature and operational space and distribution capability grow. Navy operational global ocean forecast subsets for U.S waters comprise the initial ocean prediction fields resident on the NCDDC production server. The NGI/NCDDC developmental server currently includes the Naval Research Laboratory Inter-America Seas

Regional Ocean Data Assimilation

KAUST Repository

Edwards, Christopher A.; Moore, Andrew M.; Hoteit, Ibrahim; Cornuelle, Bruce D.

2015-01-01

This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal

Nuclear Physics on the Light Front

OpenAIRE

Miller, Gerald A.

1999-01-01

High energy scattering experiments involving nuclei are typically analyzed in terms of light front variables. The desire to provide realistic, relativistic wave functions expressed in terms of these variables led me to try to use light front dynamics to compute nuclear wave functions. The progress is summarized here.

Submesoscale CO2 variability across an upwelling front off Peru

Science.gov (United States)

Köhn, Eike E.; Thomsen, Sören; Arévalo-Martínez, Damian L.; Kanzow, Torsten

2017-12-01

As a major source for atmospheric CO2, the Peruvian upwelling region exhibits strong variability in surface fCO2 on short spatial and temporal scales. Understanding the physical processes driving the strong variability is of fundamental importance for constraining the effect of marine emissions from upwelling regions on the global CO2 budget. In this study, a frontal decay on length scales of 𝒪(10 km) was observed off the Peruvian coast following a pronounced decrease in down-frontal (equatorward) wind speed with a time lag of 9 h. Simultaneously, the sea-to-air flux of CO2 on the inshore (cold) side of the front dropped from up to 80 to 10 mmol m-2 day-1, while the offshore (warm) side of the front was constantly outgassing at a rate of 10-20 mmol m-2 day-1. Based on repeated ship transects the decay of the front was observed to occur in two phases. The first phase was characterized by a development of coherent surface temperature anomalies which gained in amplitude over 6-9 h. The second phase was characterized by a disappearance of the surface temperature front within 6 h. Submesoscale mixed-layer instabilities were present but seem too slow to completely remove the temperature gradient in this short time period. Dynamics such as a pressure-driven gravity current appear to be a likely mechanism behind the evolution of the front.

Ethane ocean on Titan

Science.gov (United States)

Lunine, J. I.; Stevenson, D. J.; Yung, Y.L.

1983-01-01

Voyager I radio occultation data is employed to develop a qualitative model of an ethane ocean on Titan. It is suggested that the ocean contains 25 percent CH4 and that the ocean is in dynamic equilibrium with an N2 atmosphere. Previous models of a CH4 ocean are discounted due to photolysis rates of CH4 gas. Tidal damping of Titan's orbital eccentricity is taken as evidence for an ocean layer approximately 1 km deep, with the ocean floor being covered with a solid C2H2 layer 100 to 200 m thick. The photolytic process disrupting the CH4, if the estimates of the oceanic content of CH4 are correct, could continue for at least one billion years. Verification of the model is dependent on detecting CH4 clouds in the lower atmosphere, finding C2H6 saturation in the lower troposphere, or obtaining evidence of a global ocean.

Regional Ocean Data Assimilation

KAUST Repository

Edwards, Christopher A.

2015-01-03

This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

Radiation hydrodynamical instabilities in cosmological and galactic ionization fronts

Science.gov (United States)

Whalen, Daniel J.; Norman, Michael L.

2011-11-01

Ionization fronts, the sharp radiation fronts behind which H/He ionizing photons from massive stars and galaxies propagate through space, were ubiquitous in the universe from its earliest times. The cosmic dark ages ended with the formation of the first primeval stars and galaxies a few hundred Myr after the Big Bang. Numerical simulations suggest that stars in this era were very massive, 25-500 solar masses, with H(II) regions of up to 30,000 light-years in diameter. We present three-dimensional radiation hydrodynamical calculations that reveal that the I-fronts of the first stars and galaxies were prone to violent instabilities, enhancing the escape of UV photons into the early intergalactic medium (IGM) and forming clumpy media in which supernovae later exploded. The enrichment of such clumps with metals by the first supernovae may have led to the prompt formation of a second generation of low-mass stars, profoundly transforming the nature of the first protogalaxies. Cosmological radiation hydrodynamics is unique because ionizing photons coupled strongly to both gas flows and primordial chemistry at early epochs, introducing a hierarchy of disparate characteristic timescales whose relative magnitudes can vary greatly throughout a given calculation. We describe the adaptive multistep integration scheme we have developed for the self-consistent transport of both cosmological and galactic ionization fronts.

Muon front end for the neutrino factory

Directory of Open Access Journals (Sweden)

C. T. Rogers

2013-04-01

Full Text Available In the neutrino factory, muons are produced by firing high-energy protons onto a target to produce pions. The pions decay to muons and pass through a capture channel known as the muon front end, before acceleration to 12.6 GeV. The muon front end comprises a variable frequency rf system for longitudinal capture and an ionization cooling channel. In this paper we detail recent improvements in the design of the muon front end.

Automated Detection of Fronts using a Deep Learning Convolutional Neural Network

Science.gov (United States)

Biard, J. C.; Kunkel, K.; Racah, E.

2017-12-01

very well with the truth dataset. There is a slight underestimate in total numbers in the CNN results but the spatial pattern is a close match. The categorization of front types by CNN is best for cold and occluded and worst for warm. These initial results from our ongoing development highlight the great promise of this technology.

Blue Ocean Thinking

Science.gov (United States)

Orem, Donna

2016-01-01

This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

Ocean Sense: Student-Led, Real-Time Research at the Bottom of the Ocean - Without Leaving the Classroom

Science.gov (United States)

Pelz, M.; Hoeberechts, M.; McLean, M. A.; Riddell, D. J.; Ewing, N.; Brown, J. C.

2016-12-01

This presentation outlines the authentic research experiences created by Ocean Networks Canada's Ocean Sense program, a transformative education program that connects students and teachers with place-based, real-time data via the Internet. This program, developed in collaboration with community educators, features student-centric activities, clearly outlined learning outcomes, assessment tools and curriculum aligned content. Ocean Networks Canada (ONC), an initiative of the University of Victoria, develops, operates, and maintains cabled ocean observatory systems. Technologies developed on the world-leading NEPTUNE and VENUS observatories have been adapted for small coastal installations called "community observatories," which enable community members to directly monitor conditions in the local ocean environment. Data from these observatories are fundamental to lessons and activities in the Ocean Sense program. Marketed as Ocean Sense: Local observations, global connections, the program introduces middle and high school students to research methods in biology, oceanography and ocean engineering. It includes a variety of resources and opportunities to excite students and spark curiosity about the ocean environment. The program encourages students to connect their local observations to global ocean processes and the observations of students in other geographic regions. Connection to place and local relevance of the program is enhanced through an emphasis on Indigenous and place-based knowledge. The program promotes of cross-cultural learning with the inclusion of Indigenous knowledge of the ocean. Ocean Sense provides students with an authentic research experience by connecting them to real-time data, often within their own communities. Using the freely accessible data portal, students can curate the data they need from a range of instruments and time periods. Further, students are not restricted to their local community; if their question requires a greater range of

Modes of uranium occurrences in Colorado Front Range

International Nuclear Information System (INIS)

Carpenter, R.H.; Gallagher, J.R.L.; Huber, G.C.

1978-01-01

This report is an analysis of the various types of uranium occurrences in the Colorado Front Range and the environments in which they developed. The early Proterozoic crust of this region is believed to have been a platform on which intermediate to felsic volcanic centers formed. Some units in the volcanic stratigraphy as well as in the sediments which were deposited in the shallow, intervening seaways are thought to have been uraniferous. Tectonism, occurring about 1.7 By ago, was accompanied and followed by three periods of Precambrian igneous activity. The volcanics and sediments were converted to a metavolcanic-metasedimentary sequence known as the Idaho Springs Formation. Some of the syngenetic uranium remaining in the volcanics and sediments after metamorphism may have been mobilized and incorporated within the Silver Plume plutons and the Pikes Peak batholith and concentrated in pegmatite dikes, pegmatites and fractured areas in the hood zones in the apophyses, or along the flanks of these intrusives. Some or most of the uranium found in these sites may have been generated deeper in the continental plate. Uplift of the Front Range in the Late Mississippian and arching during the Laramide with accompanying faulting set the stage for early and mid-Tertiary igneous activity and associated uranium mineralization. The source of the early and mid-Tertiary uranium mineralization is a point of current debate. Exploration for uranium in the igneous and metamorphic terrain of the Front Range is summarized, and models of each major uranium occurrence are described. Finally, the Front Range exploration potential for uranium is outlined

Hindrances to bistable front propagation: application to Wolbachia invasion.

Science.gov (United States)

Nadin, Grégoire; Strugarek, Martin; Vauchelet, Nicolas

2018-05-01

We study the biological situation when an invading population propagates and replaces an existing population with different characteristics. For instance, this may occur in the presence of a vertically transmitted infection causing a cytoplasmic effect similar to the Allee effect (e.g. Wolbachia in Aedes mosquitoes): the invading dynamics we model is bistable. We aim at quantifying the propagules (what does it take for an invasion to start?) and the invasive power (how far can an invading front go, and what can stop it?). We rigorously show that a heterogeneous environment inducing a strong enough population gradient can stop an invading front, which will converge in this case to a stable front. We characterize the critical population jump, and also prove the existence of unstable fronts above the stable (blocking) fronts. Being above the maximal unstable front enables an invading front to clear the obstacle and propagate further. We are particularly interested in the case of artificial Wolbachia infection, used as a tool to fight arboviruses.

Springer handbook of ocean engineering

CERN Document Server

Xiros, Nikolaos

2016-01-01

The handbook is the definitive reference for the interdisciplinary field that is ocean engineering. It integrates the coverage of fundamental and applied material and encompasses a diverse spectrum of systems, concepts and operations in the maritime environment, as well as providing a comprehensive update on contemporary, leading-edge ocean technologies. Coverage includes but is not limited to; an overview of ocean science, ocean signals and instrumentation, coastal structures, developments in ocean energy technologies, and ocean vehicles and automation. The handbook will be of interest to practitioners in a range of offshore industries and naval establishments as well as academic researchers and graduate students in ocean, coastal, offshore, and marine engineering and naval architecture.

Ocean CO{sub 2} disposal

Energy Technology Data Exchange (ETDEWEB)

Shindo, Yuji; Hakuta, Toshikatsu [National Inst. of Materials and Chemical Research, AIST, MITI, Higashi, Tsukuba, Ibaraki (Japan)

1993-12-31

Most countries in the world will continue to depend on fossil fuels for their main energy at least for half a country, even in the confrontation with the threat of global warming. This indicates that the development of CO{sub 2} removal technologies such as recovering CO{sub 2} from flue gases and sequestering it of in the deep oceans or subterranean sites is necessary, at least until non-fossil fuel dependent society is developed. Ocean CO{sub 2} disposal is one of the promising options for the sequestration of CO{sub 2} recovered from flue gases. Oceans have sufficient capacity to absorb all the CO{sub 2} emitted in the world. It is very significant to research and develop the technologies for ocean CO{sub 2} disposal.

A socio-internactive framework for the fuzzy front end

NARCIS (Netherlands)

Smulders, Frido E.; van den Broek, Egon; van der Voort, Mascha C.; Fernandes, A.; Teixeira, A.; Natal Jorge, R.

2007-01-01

This paper aims to illustrate that the dominating rational-analytic perspective on the Fuzzy Front End (FFE) of innovation could benefit by a complementary socio-interactive perspective that addresses the social processes during the FFE. We have developed a still fledgling socio-interactive

Development of three dimensional ocean current model for coastal region

International Nuclear Information System (INIS)

Kobayashi, Takuya

1999-12-01

In order to study the migration behavior of radionuclides released into a coastal region around Japan, Princeton Ocean Model (POM) was introduced. This three-dimensional ocean current model was modified to be applied for oceanic simulations around Japan. This report describes the governing equations, numerical methods and model improvements. In addition, database system which is utilized for calculations and visualization system for graphical outputs are also described. Model simulation was carried out at off the area of Shimokita. Aomori-ken, Japan to investigate the effects of the boundary conditions on simulated results. (author)

Tides. Ocean Related Curriculum Activities.

Science.gov (United States)

Marrett, Andrea

The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

Radiative thermal conduction fronts

International Nuclear Information System (INIS)

Borkowski, K.J.; Balbus, S.A.; Fristrom, C.C.

1990-01-01

The discovery of the O VI interstellar absorption lines in our Galaxy by the Copernicus observatory was a turning point in our understanding of the Interstellar Medium (ISM). It implied the presence of widespread hot (approx. 10 to the 6th power K) gas in disk galaxies. The detection of highly ionized species in quasi-stellar objects' absorption spectra may be the first indirect observation of this hot phase in external disk galaxies. Previous efforts to understand extensive O VI absorption line data from our Galaxy were not very successful in locating the regions where this absorption originates. The location at interfaces between evaporating ISM clouds and hot gas was favored, but recent studies of steady-state conduction fronts in spherical clouds by Ballet, Arnaud, and Rothenflug (1986) and Bohringer and Hartquist (1987) rejected evaporative fronts as the absorption sites. Researchers report here on time-dependent nonequilibrium calculations of planar conductive fronts whose properties match well with observations, and suggest reasons for the difference between the researchers' results and the above. They included magnetic fields in additional models, not reported here, and the conclusions are not affected by their presence

Earthquakes drive large-scale submarine canyon development and sediment supply to deep-ocean basins.

Science.gov (United States)

Mountjoy, Joshu J; Howarth, Jamie D; Orpin, Alan R; Barnes, Philip M; Bowden, David A; Rowden, Ashley A; Schimel, Alexandre C G; Holden, Caroline; Horgan, Huw J; Nodder, Scott D; Patton, Jason R; Lamarche, Geoffroy; Gerstenberger, Matthew; Micallef, Aaron; Pallentin, Arne; Kane, Tim

2018-03-01

Although the global flux of sediment and carbon from land to the coastal ocean is well known, the volume of material that reaches the deep ocean-the ultimate sink-and the mechanisms by which it is transferred are poorly documented. Using a globally unique data set of repeat seafloor measurements and samples, we show that the moment magnitude ( M w ) 7.8 November 2016 Kaikōura earthquake (New Zealand) triggered widespread landslides in a submarine canyon, causing a powerful "canyon flushing" event and turbidity current that traveled >680 km along one of the world's longest deep-sea channels. These observations provide the first quantification of seafloor landscape change and large-scale sediment transport associated with an earthquake-triggered full canyon flushing event. The calculated interevent time of ~140 years indicates a canyon incision rate of 40 mm year -1 , substantially higher than that of most terrestrial rivers, while synchronously transferring large volumes of sediment [850 metric megatons (Mt)] and organic carbon (7 Mt) to the deep ocean. These observations demonstrate that earthquake-triggered canyon flushing is a primary driver of submarine canyon development and material transfer from active continental margins to the deep ocean.

Fundão Dam collapse: Oceanic dispersion of River Doce after the greatest Brazilian environmental accident.

Science.gov (United States)

Marta-Almeida, Martinho; Mendes, Renato; Amorim, Fabiola N; Cirano, Mauro; Dias, João M

2016-11-15

On 5 November 2015, the Fundão tailings dam collapsed and its content first reached River Doce and then the Atlantic Ocean by 22 November. This study focuses on the oceanic time and space patterns of river discharge dispersion. By using an ocean model together with nLw(555) and RGB images from MODIS sensors, the river plume was followed for 2months after the arrival of the tailings at the ocean. The results show the huge effect of this accident and reveal that riverine waters may have dispersed hundreds of kilometres, reaching regions as far as the shelf in front of the city of Rio de Janeiro. The movement of the freshwater was essentially to the south in accordance with the seasonal wind regime. Episodic frontal systems, leading to wind reversion, and oceanic mesoscale features contribute to the offshore dispersion of the plume. The region more often in contact with the riverine waters was located at the inner shelf between the river mouth and the city of Vitória, turning to the outer shelf and shelf break at lower latitudes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Testing and development of an OWC MRI compatible PET insert front-end

Energy Technology Data Exchange (ETDEWEB)

Konstantinou, G.; Ali, W.; Chil, R.; Cossu, G.; Ciaramella, E.; Vaquero, J.J.

2016-07-01

We present the design and development of a positron emission tomography (PET) detector module that could be used inside magnetic resonance imager (MRI). Critical factors compromising this combination have been studied and different solutions have been offered. Our design divides the detector module in two sections: one is the insert front-end that is placed inside the MRI and that comprises of a scintillator, a silicon photomultiplier and minimum analog electronics. The analog pulses are sent to the second section, the back-end digitalization and reconstruction module. The analog link is implemented using optical wireless communication (OWC) techniques. In this work we study how such a setting retains all the necessary characteristics for the detection and characterization of gamma scintillation events, providing sufficient communication quality with low consumption and minimizing the need for space. Possible multiplexing schemes for achieving the necessary transmission with less communication channels are also proposed and studied. A series of tests and measurements on different settings demonstrate the viability of this technique. When fully developed, it can provide a cost effective alternative for the industrial production of a flexible and customizable modular PET detector insert that can be applied to pre-existing small animal or human MRI settings, only minimally affecting the size of the MRI bore, without compromising the PET signal quality. (Author)

Impact of CD68/(CD3+CD20 ratio at the invasive front of primary tumors on distant metastasis development in breast cancer.

Directory of Open Access Journals (Sweden)

Noemí Eiró

Full Text Available Tumors are infiltrated by macrophages, T and B-lymphocytes, which may favor tumor development by promoting angiogenesis, growth and invasion. The aim of this study was to investigate the clinical relevance of the relative amount of macrophages (CD68⁺, T-cells (CD3⁺ and B-cells (CD20⁺ at the invasive front of breast carcinomas, and the expression of matrix metalloproteases (MMPs and their inhibitors (TIMPs either at the invasive front or at the tumor center. We performed an immunohistochemical study counting CD3, CD20 and CD68 positive cells at the invasive front, in 102 breast carcinomas. Also, tissue sections were stained with MMP-2, -9, -11, -14 and TIMP-2 antibodies, and immunoreactivity location, percentage of reactive area and intensity were determined at the invasive front and at the tumor center. The results showed that an increased CD68 count and CD68/(CD3+CD20 ratio were directly associated with both MMP-11 and TIMP-2 expression by mononuclear inflammatory cells at the tumor center (p = 0.041 and p = 0.025 for CD68 count and p = 0.001 and p = 0.045 for ratio, respectively for MMP-11 and TIMP-2. In addition, a high CD68/(CD3+CD20 ratio (>0.05 was directly associated with a higher probability of shortened relapse-free survival. Multivariate analysis revealed that CD68/(CD3+CD20 ratio was an independent factor associated with distant relapse-free survival (RR: 2.54, CI: (1.23-5.24, p<0.01. Therefore, CD68/(CD3+CD20 ratio at the invasive front could be used as an important prognostic marker.

Ocean energy

International Nuclear Information System (INIS)

2006-01-01

This annual evaluation is a synthesis of works published in 2006. Comparisons are presented between the wind power performances and European Commission White Paper and Biomass action plan objectives. The sector covers the energy exploitation of all energy flows specifically supplied by the seas and oceans. At present, most efforts in both research and development and in experimental implementation are concentrated on tidal currents and wave power. 90% of today worldwide ocean energy production is represented by a single site: the Rance Tidal Power Plant. Ocean energies must face up two challenges: progress has to be made in finalizing and perfecting technologies and costs must be brought under control. (A.L.B.)

An initial assessment of Ocean Energy Resources in the Western Indian Ocean

Energy Technology Data Exchange (ETDEWEB)

Hammar, Linus; Ehnberg, Jimmy

2011-07-01

The demand for modern energy is accelerating in the Western Indian Ocean (coastal East Africa). A mixture of different energy sources will by necessity be the option for the long-term future and the most adequate solutions naturally vary between locations. The vast coastlines and many islands of the region make ocean energy (OE) a relevant field to explore. With an early understanding of the resources strategic planning towards sustainable development is facilitate. Moreover, early awareness facilitates a respectful integration of new technologies in the fragile and for local people invaluable ecosystems. This study provides a first assessment of the frontier OE technologies and corresponding resources in the region. Five renewable Ocean Energy technologies have been reviewed and the physical resource abundance for respective energy source has been screened based on available literature and databases. The Western Indian Ocean is shared between nine African countries and two French departments. The studied countries are the Comoros, Kenya, Madagascar, Mauritius, Mayotte, Mozambique, the Seychelles, Tanzania, and Reunion. The energy situation is insufficient throughout the region, either as consequence of lacking domestic energy sources or rudimentary grid extension. The results indicate that ocean energy resources are abundant in much of the region, but different sources have potential in different areas. Several countries have favourable physical conditions for extracting energy from waves and from the temperature gradient between the surface and deep water. Wave power is a young but currently available technology which can be utilized for both large- and small-scale applications. Ocean Thermal Energy Conversion is a technology under development that, once proven, may be applicable for large-scale power production. The physical conditions for small-scale tidal barrage power, tidal stream power, and ocean current power are less pronounced but may be of interest at

Impact of patient suicide on front-line staff in Ireland.

LENUS (Irish Health Repository)

Gaffney, Paul

2009-08-01

Research and anecdotal evidence suggests that coming to terms with the suicide of a patient can be extremely distressing for front-line professionals. Some research also suggests that exposure to such situations can undermine professionals\\' functioning and feelings of competence, cause them to question their professional standing and ultimately contribute to burnout. A survey of 447 front-line professionals\\' experiences of patient suicide was undertaken to further explore these issues. Thematic analysis of open-ended questionnaire items revealed that concerns for the bereaved family, feelings of responsibility for the death and having a close therapeutic relationship with the client are key factors that influence the adjustment and coping of a health professional in the aftermath of the death of a client by suicide. The results are discussed with a focus on the impact of suicide on front-line staff, the need for ongoing support and training and the development of specific post-suicide protocols.

Blue ocean strategy.

Science.gov (United States)

Kim, W Chan; Mauborgne, Renée

2004-10-01

Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

End-Users, Front Ends and Librarians.

Science.gov (United States)

Bourne, Donna E.

1989-01-01

The increase in end-user searching, the advantages and limitations of front ends, and the role of the librarian in end-user searching are discussed. It is argued that librarians need to recognize that front ends can be of benefit to themselves and patrons, and to assume the role of advisors and educators for end-users. (37 references) (CLB)

New results in light-front phenomenology

International Nuclear Information System (INIS)

Brodsky, S.J.

2005-01-01

The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a trivial vacuum. In this talk I review the theoretical methods and constraints which can be used to determine these central elements of QCD phenomenology. The freedom to choose the light-like quantization four-vector provides an explicitly covariant formulation of light-front quantization and can be used to determine the analytic structure of light-front wave functions and define a kinematical definition of angular momentum. The AdS/CFT correspondence of large N c supergravity theory in higher-dimensional anti-de Sitter space with supersymmetric QCD in four-dimensional space-time has interesting implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for exclusive processes. String/gauge duality also predicts the QCD power-law behavior of light-front Fock-state hadronic wavefunctions with arbitrary orbital angular momentum at high momentum transfer. The form of these near-conformal wavefunctions can be used as an initial ansatz for a variational treatment of the light-front QCD Hamiltonian. The light-front Fock-state wavefunctions encode the bound state properties of hadrons in terms of their quark and gluon degrees of freedom at the amplitude level. The nonperturbative Fock-state wavefunctions contain intrinsic gluons, and sea quarks at any scale Q with asymmetries such as s(x) ≠ s-bar(x), u-bar(x) ≠ d-bar(x). Intrinsic charm and bottom quarks appear at large x in the light-front wavefunctions since this minimizes the invariant mass and off-shellness of the higher Fock state. In the case of nuclei, the Fock state expansion contains 'hidden color' states which cannot be classified in terms of of nucleonic degrees of freedom. I also briefly review recent analyses which show that some

Ocean Acidification | Smithsonian Ocean Portal

Science.gov (United States)

Natural History Blog For Educators At The Museum Media Archive Ocean Life & Ecosystems Mammals Sharks Mangroves Poles Census of Marine Life Planet Ocean Tides & Currents Waves & Storms The Seafloor ocean is affected. Such a relatively quick change in ocean chemistry doesn't give marine life, which

Ocean energies

International Nuclear Information System (INIS)

Charlier, R.H.; Justus, J.R.

1993-01-01

This timely volume provides a comprehensive review of current technology for all ocean energies. It opens with an analysis of ocean thermal energy conversion (OTEC), with and without the use of an intermediate fluid. The historical and economic background is reviewed, and the geographical areas in which this energy could be utilized are pinpointed. The production of hydrogen as a side product, and environmental consequences of OTEC plants are considered. The competitiveness of OTEC with conventional sources of energy is analysed. Optimisation, current research and development potential are also examined. Separate chapters provide a detailed examination of other ocean energy sources. The possible harnessing of solar ponds, ocean currents, and power derived from salinity differences is considered. There is a fascinating study of marine winds, and the question of using the ocean tides as a source of energy is examined, focussing on a number of tidal power plant projects, including data gathered from China, Australia, Great Britain, Korea and the USSR. Wave energy extraction has excited recent interest and activity, with a number of experimental pilot plants being built in northern Europe. This topic is discussed at length in view of its greater chance of implementation. Finally, geothermal and biomass energy are considered, and an assessment of their future is given. The authors also distinguished between energy schemes which might be valuable in less-industrialized regions of the world, but uneconomical in the developed countries. A large number of illustrations support the text. This book will be of particular interest to energy economists, engineers, geologists and oceanographers, and to environmentalists and environmental engineers

Port Blair declaration pledged to establish and develop Andaman and Nicobar Ocean Biogeographic Information System - Meeting report

Digital Repository Service at National Institute of Oceanography (India)

Chavan, V.S.; Achuthankutty, C.T.; Nazar, A.K.A.

to implement such an inform a tion system, and monitor the progress of ANOBIS. The task force would comprise of techn i cal and da ta - management representatives from pa r - ticipating institutions, and would ensure seamless establishment and development... Declaration pledged to establish and develop Andaman and Nicobar Ocean Biogeographic Information Sy s tem* T he Andaman and Nicobar (A&N) I s- lands are located in the Indian Ocean, in the southern reaches of the Bay of Be n gal. The Andaman Sea...

The Ocean Literacy Campaign

Science.gov (United States)

Schoedinger, S. E.; Strang, C.

2008-12-01

"Ocean Literacy is an understanding of the ocean's influence on you and your influence on the ocean." This simple statement captures the spirit of a conceptual framework supporting ocean literacy (COSEE et al., 2005). The framework comprises 7 essential principles and 44 fundamental concepts an ocean literate person would know (COSEE et al., 2005). The framework is the result of an extensive grassroots effort to reach consensus on (1) a definition for ocean literacy and (2) an articulation of the most important concepts to be understood by ocean-literate citizen (Cava et al., 2005). In the process of reaching consensus on these "big ideas" about the ocean, what began as a series of workshops has emerged as a campaign "owned" by an ever-expanding community of individuals, organizations and networks involved in developing and promoting the framework. The Ocean Literacy Framework has provided a common language for scientists and educators working together and serves as key guidance for the ocean science education efforts. This presentation will focus on the impact this Ocean Literacy Campaign has had to date as well as efforts underway to provide additional tools to enable educators and educational policy makers to further integrate teaching and learning about the ocean and our coasts into formal K-12 education and informal education. COSEE, National Geographic Society, NOAA, College of Exploration (2005). Ocean Literacy: The Essential Principles of Ocean Sciences Grades K-12, a jointly published brochure, URL: http://www.coexploration.org/oceanliteracy/documents/OceanLitChart.pdf Cava, F., S. Schoedinger , C. Strang, and P. Tuddenham (2005). Science Content and Standards for Ocean Literacy: A Report on Ocean Literacy, URL: http://www.coexploration.org/oceanliteracy/documents/OLit2004-05_Final_Report.pdf.

Granular-front formation in free-surface flow of concentrated suspensions

Science.gov (United States)

Leonardi, Alessandro; Cabrera, Miguel; Wittel, Falk K.; Kaitna, Roland; Mendoza, Miller; Wu, Wei; Herrmann, Hans J.

2015-11-01

A granular front emerges whenever the free-surface flow of a concentrated suspension spontaneously alters its internal structure, exhibiting a higher concentration of particles close to its front. This is a common and yet unexplained phenomenon, which is usually believed to be the result of fluid convection in combination with particle size segregation. However, suspensions composed of uniformly sized particles also develop a granular front. Within a large rotating drum, a stationary recirculating avalanche is generated. The flowing material is a mixture of a viscoplastic fluid obtained from a kaolin-water dispersion with spherical ceramic particles denser than the fluid. The goal is to mimic the composition of many common granular-fluid materials, such as fresh concrete or debris flow. In these materials, granular and fluid phases have the natural tendency to separate due to particle settling. However, through the shearing caused by the rotation of the drum, a reorganization of the phases is induced, leading to the formation of a granular front. By tuning the particle concentration and the drum velocity, it is possible to control this phenomenon. The setting is reproduced in a numerical environment, where the fluid is solved by a lattice-Boltzmann method, and the particles are explicitly represented using the discrete element method. The simulations confirm the findings of the experiments, and provide insight into the internal mechanisms. Comparing the time scale of particle settling with the one of particle recirculation, a nondimensional number is defined, and is found to be effective in predicting the formation of a granular front.

QCD Phenomenology and Light-Front Wavefunctions

International Nuclear Information System (INIS)

Brodsky, Stanley J.

2001-01-01

A natural calculus for describing the bound-state structure of relativistic composite systems in quantum field theory is the light-front Fock expansion which encodes the properties of a hadrons in terms of a set of frame-independent n-particle wavefunctions. Light-front quantization in the doubly-transverse light-cone gauge has a number of remarkable advantages, including explicit unitarity, a physical Fock expansion, the absence of ghost degrees of freedom, and the decoupling properties needed to prove factorization theorems in high momentum transfer inclusive and exclusive reactions. A number of applications are discussed in these lectures, including semileptonic B decays, two-photon exclusive reactions, diffractive dissociation into jets, and deeply virtual Compton scattering. The relation of the intrinsic sea to the light-front wavefunctions is discussed. Light-front quantization can also be used in the Hamiltonian form to construct an event generator for high energy physics reactions at the amplitude level. The light-cone partition function, summed over exponentially weighted light-cone energies, has simple boost properties which may be useful for studies in heavy ion collisions. I also review recent work which shows that the structure functions measured in deep inelastic lepton scattering are affected by final-state rescattering, thus modifying their connection to light-front probability distributions. In particular, the shadowing of nuclear structure functions is due to destructive interference effects from leading-twist diffraction of the virtual photon, physics not included in the nuclear light-cone wavefunctions

Functional description of APS beamline front ends

International Nuclear Information System (INIS)

Kuzay, T.

1993-02-01

Traditional synchrotron sources were designed to produce bending magnet radiation and have proven to be an essential scientific tool. Currently, a new generation of synchrotron sources is being built that will be able to accommodate a large number of insertion device (ID) and high quality bending magnet (BM) sources. One example is the 7-GeV Advanced Photon Source (APS) now under construction at Argonne National Laboratory. The research and development effort at the APS is designed to fully develop the potential of this new generation of synchrotron sources. Of the 40 straight sections in the APS storage ring, 34 will be available for IDs. The remaining six sections are reserved for the storage ring hardware and diagnostics. Although the ring incorporates 80 BMs, only 40 of them can be used to extract radiation. The accelerator hardware shadows five of these 40 bending magnets, so the maximum number of BM sources on the lattice is 35. Generally, a photon beamline consists of four functional sections. The first section is the ID or the BM, which provides the radiation source. The second section, which is immediately outside the storage ring but inside a concrete shielding tunnel, is the front end, which is designed to control, define, and/or confine the x-ray beam. In the case of the APS, the front ends are designed to confine the photon beam. The third section, just outside the concrete shielding tunnel and on the experimental floor, is the first optics enclosure, which contains optics to filter and monochromatize the photon beam. The fourth section of a beamline consists of beam transports, additional optics, and experiment stations to do the scientific investigations. This document describes only the front ends of the APS beamlines

Hydrological and chlorofluoromethane measurements of the Indonesian throughflow entering the Indian Ocean

Science.gov (United States)

Fieux, M.; Andrié, C.; Charriaud, E.; Ilahude, A. G.; Metzl, N.; Molcard, R.; Swallow, J. C.

1996-05-01

The Java Australia Dynamic Experiment high-resolution February-March 1992 conductivity-temperature-depth and chlorofluoromethane section obtained between Australia and Bali and on the sills between Flores, Sumba, Sawu, Roti, and the Australian continental shelf allows detailed examination of the water masses distribution and their inferred circulation. A sharp hydrological front between the Indonesian waters and the southern Indian Ocean waters is found between 13°S and 14°S in both seasons (February-March 1992 and August 1989). It separates the high-salinity surface waters to the south from the lower-salinity surface waters derived from the Indonesian Seas to the north. It reaches the surface in February 1992, whereas it was capped by a particularly low salinity surface layer in August 1989. Near Bali, the NW monsoon of February-March produces large intrusions of low-salinity water from the Java Sea, through Lombok Strait in the upper 100 m. At depth, the North Indian Intermediate Water, flowing along the Indonesian coast, brings salty, low-oxygen and low-chlorofluorocarbon water. It enters the Sawu Sea through Sumba Strait toward the east, while it undergoes strong mixing with the Indonesian Seas water. The primary pathway of the Indonesian waters is found north of the front and south of the North Indian Intermediate Water, between 13°S and 9°30'S, and the associated salinity minimum can be followed all across the Indian Ocean.

Development and validation of a regional coupled forecasting system for S2S forecasts

Science.gov (United States)

Sun, R.; Subramanian, A. C.; Hoteit, I.; Miller, A. J.; Ralph, M.; Cornuelle, B. D.

2017-12-01

Accurate and efficient forecasting of oceanic and atmospheric circulation is essential for a wide variety of high-impact societal needs, including: weather extremes; environmental protection and coastal management; management of fisheries, marine conservation; water resources; and renewable energy. Effective forecasting relies on high model fidelity and accurate initialization of the models with observed state of the ocean-atmosphere-land coupled system. A regional coupled ocean-atmosphere model with the Weather Research and Forecasting (WRF) model and the MITGCM ocean model coupled using the ESMF (Earth System Modeling Framework) coupling framework is developed to resolve mesoscale air-sea feedbacks. The regional coupled model allows oceanic mixed layer heat and momentum to interact with the atmospheric boundary layer dynamics at the mesoscale and submesoscale spatiotemporal regimes, thus leading to feedbacks which are otherwise not resolved in coarse resolution global coupled forecasting systems or regional uncoupled forecasting systems. The model is tested in two scenarios in the mesoscale eddy rich Red Sea and Western Indian Ocean region as well as mesoscale eddies and fronts of the California Current System. Recent studies show evidence for air-sea interactions involving the oceanic mesoscale in these two regions which can enhance predictability on sub seasonal timescale. We will present results from this newly developed regional coupled ocean-atmosphere model for forecasts over the Red Sea region as well as the California Current region. The forecasts will be validated against insitu observations in the region as well as reanalysis fields.

Mission Specific Platforms: Past achievements and future developments in European led ocean research drilling.

Science.gov (United States)

Cotterill, Carol; McInroy, David; Stevenson, Alan

2013-04-01

Mission Specific Platform (MSP) expeditions are operated by the European Consortium for Ocean Research Drilling (ECORD). Each MSP expedition is unique within the Integrated Ocean Drilling Program (IODP). In order to complement the abilities of the JOIDES Resolution and the Chikyu, the ECORD Science Operator (ESO) must source vessels and technology suitable for each MSP proposal on a case-by-case basis. The result is that ESO can meet scientific requirements in a flexible manner, whilst maintaining the measurements required for the IODP legacy programme. The process of tendering within EU journals for vessels and technology means that the planning process for each MSP Expedition starts many years in advance of the operational phase. Involvement of proposal proponents from this early stage often leads to the recognition for technological research and development to best meet the scientific aims and objectives. One example of this is the planning for the Atlantis Massif proposal, with collaborative development between the British Geological Survey (BGS) and MARUM, University of Bremen, on suitable instruments for seabed drills, with the European Petrophysics Consortium (EPC) driving the development of suitable wireline logging tools that can be used in association with such seabed systems. Other technological developments being undertaken within the European IODP community include in-situ pressure sampling for gas hydrate expeditions, deep biosphere and fluid sampling equipment and CORK technology. This multi-national collaborative approach is also employed by ESO in the operational phase. IODP Expedition 302 ACEX saw vessel and ice management support from Russia and Sweden to facilitate the first drilling undertaken in Arctic sea ice. A review of MSP expeditions past, present and future reveal the significant impact of European led operations and scientific research within the current IODP programme, and also looking forward to the start of the new International

Light-Front Holography and AdS/QCD Correspondence

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; de Teramond, Guy F.

2008-04-23

Light-Front Holography is a remarkable consequence of the correspondence between string theory in AdS space and conformal field theories in physical-space time. It allows string modes {Phi}(z) in the AdS fifth dimension to be precisely mapped to the light-front wavefunctions of hadrons in terms of a specific light-front impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron. This mapping was originally obtained by matching the exact expression for electromagnetic current matrix elements in AdS space with the corresponding exact expression for the current matrix element using light-front theory in physical space-time. More recently we have shown that one obtains the identical holographic mapping using matrix elements of the energy-momentum tensor, thus providing an important consistency test and verification of holographic mapping from AdS to physical observables defined on the light-front. The resulting light-front Schrodinger equations predicted from AdS/QCD give a good representation of the observed meson and baryon spectra and give excellent phenomenological predictions for amplitudes such as electromagnetic form factors and decay constants.

Feedback from operational experience in front-end transportation

International Nuclear Information System (INIS)

Mondonel, J.L.; Parison, C.

1998-01-01

Transport forms an integral part of the nuclear fuel cycle, representing the strategic link between each stage of the cycle. In a way there is a transport cycle that parallels the nuclear fuel cycle. This concerns particularly the front-end of the cycle whose steps - mining conversion, enrichment and fuel fabrication - require numerous transports. Back-end shipments involve a handful of countries, but front-end transports involve all five continents, and many exotic countries. All over Europe such transports are routinely performed with an excellent safety track record. Transnucleaire dominates the French nuclear transportation market and carries out both front and back-end transports. For instance in 1996 more than 28,400 front-end packages were transported as well as more than 3,600 back-end packages. However front-end transport is now a business undergoing much change. A nuclear transportation company must now cope with an evolving picture including new technical requirements, new transportation schemes and new business conditions. This paper describes the latest evolutions in terms of front-end transportation and the way this activity is carried out by Transnucleaire, and goes on to discuss future prospects. (authors)

Managing Controversies in the Fuzzy Front End

DEFF Research Database (Denmark)

Christiansen, John K.; Gasparin, Marta

2016-01-01

This research investigates the controversies that emerge in the fuzzy front end (FFE) and how they are closed so the innovation process can move on. The fuzzy front has been characterized in the literature as a very critical phase, but controversies in the FFE have not been studied before....... The analysis investigates the microprocesses around the controversies that emerge during the fuzzy front end of four products. Five different types of controversies are identified: profit, production, design, brand and customers/market. Each controversy represents a threat, but also an opportunity to search...

Spin-1 particles with light-front approach

Directory of Open Access Journals (Sweden)

de Melo J.P.B.C.

2014-06-01

Full Text Available For the vector sector, i.e, mesons with spin-1, the electromagnetic form factors and anothers observables are calculated with the light-front approach. However, the light-front quantum field theory have some problems, for example, the rotational symmetry breaking. We solve that problem added the zero modes contribuition to the matrix elements of the electromagnetic current, besides the valence contribuition. We found that among the four independent matrix elements of the plus component in the light-front helicity basis only the 0 → 0 one carries zero mode contributions.

OceanSITES format and Ocean Observatory Output harmonisation: past, present and future

Science.gov (United States)

Pagnani, Maureen; Galbraith, Nan; Diggs, Stephen; Lankhorst, Matthias; Hidas, Marton; Lampitt, Richard

2015-04-01

The Global Ocean Observing System (GOOS) initiative was launched in 1991, and was the first step in creating a global view of ocean observations. In 1999 oceanographers at the OceanObs conference envisioned a 'global system of eulerian observatories' which evolved into the OceanSITES project. OceanSITES has been generously supported by individual oceanographic institutes and agencies across the globe, as well as by the WMO-IOC Joint Technical Commission for Oceanography and Marine Meteorology (under JCOMMOPS). The project is directed by the needs of research scientists, but has a strong data management component, with an international team developing content standards, metadata specifications, and NetCDF templates for many types of in situ oceanographic data. The OceanSITES NetCDF format specification is intended as a robust data exchange and archive format specifically for time-series observatory data from the deep ocean. First released in February 2006, it has evolved to build on and extend internationally recognised standards such as the Climate and Forecast (CF) standard, BODC vocabularies, ISO formats and vocabularies, and in version 1.3, released in 2014, ACDD (Attribute Convention for Dataset Discovery). The success of the OceanSITES format has inspired other observational groups, such as autonomous vehicles and ships of opportunity, to also use the format and today it is fulfilling the original concept of providing a coherent set of data from eurerian observatories. Data in the OceanSITES format is served by 2 Global Data Assembly Centres (GDACs), one at Coriolis, in France, at ftp://ftp.ifremer.fr/ifremer/oceansites/ and one at the US NDBC, at ftp://data.ndbc.noaa.gov/data/oceansites/. These two centres serve over 26,800 OceanSITES format data files from 93 moorings. The use of standardised and controlled features enables the files held at the OceanSITES GDACs to be electronically discoverable and ensures the widest access to the data. The Ocean

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

DEFF Research Database (Denmark)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

2017-01-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal...... the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has...... interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater...

Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland

Directory of Open Access Journals (Sweden)

I. A. Dmitrenko

2017-12-01

Full Text Available The first-ever conductivity–temperature–depth (CTD observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

Light-front quantization of the sine-Gordon model

International Nuclear Information System (INIS)

Burkardt, M.

1993-01-01

It is shown how to modify the canonical light-front quantization of the (1+1)-dimensional sine-Gordon model such that the zero-mode problem of light-front quantization is avoided. The canonical sine-Gordon Lagrangian is replaced by an effective Lagrangian which does not lead to divergences as k + =(k 0 +k 1 )/ √2 →0. After canonically quantizing the effective Lagrangian, one obtains the effective light-front Hamiltonian which agrees with the naive light-front (LF) Hamiltonian, up to one additional renormalization. The spectrum of the effective LF Hamiltonian is determined using discrete light-cone quantization and agrees with results from equal-time quantization

Influence of diatom diversity on the ocean biological carbon pump

Science.gov (United States)

Tréguer, Paul; Bowler, Chris; Moriceau, Brivaela; Dutkiewicz, Stephanie; Gehlen, Marion; Aumont, Olivier; Bittner, Lucie; Dugdale, Richard; Finkel, Zoe; Iudicone, Daniele; Jahn, Oliver; Guidi, Lionel; Lasbleiz, Marine; Leblanc, Karine; Levy, Marina; Pondaven, Philippe

2018-01-01

Diatoms sustain the marine food web and contribute to the export of carbon from the surface ocean to depth. They account for about 40% of marine primary productivity and particulate carbon exported to depth as part of the biological pump. Diatoms have long been known to be abundant in turbulent, nutrient-rich waters, but observations and simulations indicate that they are dominant also in meso- and submesoscale structures such as fronts and filaments, and in the deep chlorophyll maximum. Diatoms vary widely in size, morphology and elemental composition, all of which control the quality, quantity and sinking speed of biogenic matter to depth. In particular, their silica shells provide ballast to marine snow and faecal pellets, and can help transport carbon to both the mesopelagic layer and deep ocean. Herein we show that the extent to which diatoms contribute to the export of carbon varies by diatom type, with carbon transfer modulated by the Si/C ratio of diatom cells, the thickness of the shells and their life strategies; for instance, the tendency to form aggregates or resting spores. Model simulations project a decline in the contribution of diatoms to primary production everywhere outside of the Southern Ocean. We argue that we need to understand changes in diatom diversity, life cycle and plankton interactions in a warmer and more acidic ocean in much more detail to fully assess any changes in their contribution to the biological pump.

A Unified Model of Geostrophic Adjustment and Frontogenesis

Science.gov (United States)

Taylor, John; Shakespeare, Callum

2013-11-01

Fronts, or regions with strong horizontal density gradients, are ubiquitous and dynamically important features of the ocean and atmosphere. In the ocean, fronts are associated with enhanced air-sea fluxes, turbulence, and biological productivity, while atmospheric fronts are associated with some of the most extreme weather events. Here, we describe a new mathematical framework for describing the formation of fronts, or frontogenesis. This framework unifies two classical problems in geophysical fluid dynamics, geostrophic adjustment and strain-driven frontogenesis, and provides a number of important extensions beyond previous efforts. The model solutions closely match numerical simulations during the early stages of frontogenesis, and provide a means to describe the development of turbulence at mature fronts.

Coping on the Front-line

DEFF Research Database (Denmark)

Sanden, Guro Refsum; Lønsmann, Dorte

language boundaries in their everyday work. Despite official English language policies in the three companies, our findings show that employees face a number of different language boundaries, and that ad hoc and informal solutions in many cases are vital for successful cross-language communication. Drawing......This article investigates how front-line employees respond to English language policies implemented by the management of three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data the article examines the ways in which front-line employees cross...

TopN-Pareto Front Search

Energy Technology Data Exchange (ETDEWEB)

2016-12-21

The JMP Add-In TopN-PFS provides an automated tool for finding layered Pareto front to identify the top N solutions from an enumerated list of candidates subject to optimizing multiple criteria. The approach constructs the N layers of Pareto fronts, and then provides a suite of graphical tools to explore the alternatives based on different prioritizations of the criteria. The tool is designed to provide a set of alternatives from which the decision-maker can select the best option for their study goals.

Spectral-Efficiency - Illumination Pareto Front for Energy Harvesting Enabled VLC System

KAUST Repository

Abdelhady, Amr Mohamed Abdelaziz

2017-12-13

The continuous improvement in optical energy harvesting devices motivates visible light communication (VLC) system developers to utilize such available free energy sources. An outdoor VLC system is considered where an optical base station sends data to multiple users that are capable of harvesting the optical energy. The proposed VLC system serves multiple users using time division multiple access (TDMA) with unequal time and power allocation, which are allocated to improve the system performance. The adopted optical system provides users with illumination and data communication services. The outdoor optical design objective is to maximize the illumination, while the communication design objective is to maximize the spectral efficiency (SE). The design objectives are shown to be conflicting, therefore, a multiobjective optimization problem is formulated to obtain the Pareto front performance curve for the proposed system. To this end, the marginal optimization problems are solved first using low complexity algorithms. Then, based on the proposed algorithms, a low complexity algorithm is developed to obtain an inner bound of the Pareto front for the illumination-SE tradeoff. The inner bound for the Pareto-front is shown to be close to the optimal Pareto-frontier via several simulation scenarios for different system parameters.

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T.

1995-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T

1996-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

The development of radioactivity diffusion model in global ocean

International Nuclear Information System (INIS)

Nakano, M.; Watanabe, H.; Katagiri, H.

2000-01-01

The radioactivity diffusion model in global ocean has been developing in order to assess the long-term behavior of radioactive materials for discharge from nuclear facility. The model system consists of two parts. One is to calculate current velocity; and the other is for particle chasing. Both systems are executed by Macintosh personal computer. A lot of techniques to estimate ocean current velocity were investigated in geophysical field. The robust diagnosis model advocated by Sarmiento and Bryan was applied to build the numerical calculation system for getting the current velocity field in global scale. The latitudinal and longitudinal lattices were 2 degrees each and the number of vertical layer was 15. The movement of radioactive materials by current and diffusion were calculated using the particle chasing system. The above-mentioned current velocity field and the initial particle positions at will were read by the system. The movement of a particle was calculated using the interpolated current data step by step. The diffusion of a particle was calculated by random walk method. The model was verified by using the fallout data from atmospheric nuclear test. Yearly and latitudinal fallout data was adopted from UNSCEAR1977. The calculation result was compared with the observation data that includes total amount and vertical profile of Cs-137 and Pu-239,240 in the North Pacific Ocean. The result of the verification was agreed with the following general knowledge. Though the fallout amount between 40N and 50N was the biggest in the world, the amount in the seawater between 40N and 50N was smaller than that in south of 40N because of horizontal transportation, which carried water from north to south. As for vertical profile, Cs-137 could be accurately calculated except the surface layer. However the observation peak of Pu-239,240 existed deeper than the calculation peak. This model could calculate the vertical profile of Cs-137 because most of Cs exists as dissolved

Light-front Ward-Takahashi identity for two-fermion systems

International Nuclear Information System (INIS)

Marinho, J. A. O.; Frederico, T.; Pace, E.; Salme, G.; Sauer, P. U.

2008-01-01

We propose a three-dimensional electromagnetic current operator within light-front dynamics that satisfies a light-front Ward-Takahashi identity for two-fermion systems. The light-front current operator is obtained by a quasipotential reduction of the four-dimensional current operator and acts on the light-front valence component of bound or scattering states. A relation between the light-front valence wave function and the four-dimensional Bethe-Salpeter amplitude both for bound or scattering states is also derived, such that the matrix elements of the four-dimensional current operator can be fully recovered from the corresponding light-front ones. The light-front current operator can be perturbatively calculated through a quasipotential expansion, and the divergence of the proposed current satisfies a Ward-Takahashi identity at any given order of the expansion. In the quasipotential expansion the instantaneous terms of the fermion propagator are accounted for by the effective interaction and two-body currents. We exemplify our theoretical construction in the Yukawa model in the ladder approximation, investigating in detail the current operator at the lowest nontrivial order of the quasipotential expansion of the Bethe-Salpeter equation. The explicit realization of the light-front form of the Ward-Takahashi identity is verified. We also show the relevance of instantaneous terms and of the pair contribution to the two-body current and the Ward-Takahashi identity

Ocean Acidification: a review of the current status of research and institutional developments

NARCIS (Netherlands)

Beek, van I.J.M.; Dedert, M.

2012-01-01

Ocean acidification is defined as the change in ocean chemistry driven by the oceanic uptake of chemical inputs to the atmosphere, including carbon, nitrogen and sulphur compounds. Ocean acidification is also referred to as ‘the other CO2 problem’ of anthropogenic carbon dioxide (CO2) emissions

Fast CMOS binary front-end for silicon strip detectors at LHC experiments

CERN Document Server

Kaplon, Jan

2004-01-01

We present the design and the test results of a front-end circuit developed in a 0.25 mu m CMOS technology. The aim of this work is to study the performance of a deep submicron process in applications for fast binary front-end for silicon strip detectors. The channel comprises a fast transimpedance preamplifier working with an active feedback loop, two stages of the amplifier-integrator circuits providing 22 ns peaking time and two-stage differential discriminator. Particular effort has been made to minimize the current and the power consumption of the preamplifier, while keeping the required noise and timing performance. For a detector capacitance of 20 pF noise below 1500 e/sup -/ ENC has been achieved for 300 mu A bias current in the input transistor, which is comparable with levels achieved in the past for a front-end using bipolar input transistor. The total supply current of the front-end is 600 mu A and the power dissipation is 1.5 mW per channel. The offset spread of the comparator is below 3 mV rms.

A Serializer ASIC at 5 Gbps for Detector Front-end Electronics Readout

CERN Document Server

Gong, D; The ATLAS collaboration; Liu, T; Xiang, A; Ye, J

2010-01-01

High speed and ultra low power serial data transmission over fiber optics plays an essential roll in detector front-end electronics readout for experiments at the LHC. The ATLAS Liquid Argon Calorimeter front-end readout upgrade for the sLHC calls for an optical link system with a data bandwidth of 100 Gbps per each front-end board (FEB), a factor of 62 increase compared with the present optical link system. The transmitter of this optical link will have to withstand the radiation environment where the front-end crates are situated, and stay within the current power dissipation budget limited by the present FEB cooling capacity. To meet these challenges, we developed a 16:1 serializer based on a commercial 0.25 μm silicon-on-sapphire (SOS) CMOS technology. This serializer, designed to work at 5 Gbps, is a key component in an optical link system. Test results of this ASIC will be reported. A system design for the 100 Gbps optical link system will also be presented, with discussions about key components identi...

Direct measurement of the wetting front capillary pressure in a clay brick ceramic

Energy Technology Data Exchange (ETDEWEB)

Ioannou, Ioannis [Manchester Centre for Civil and Construction Engineering, UMIST, PO Box 88, Manchester M60 1QD (United Kingdom); Hall, Christopher [Centre for Materials Science and Engineering and School of Engineering and Electronics, University of Edinburgh, The King' s Buildings, Edinburgh EH9 3JL (United Kingdom); Wilson, Moira A [Manchester Centre for Civil and Construction Engineering, UMIST, PO Box 88, Manchester M60 1QD (United Kingdom); Hoff, William D [Manchester Centre for Civil and Construction Engineering, UMIST, PO Box 88, Manchester M60 1QD (United Kingdom); Carter, Margaret A [Manchester Centre for Civil and Construction Engineering, UMIST, PO Box 88, Manchester M60 1QD (United Kingdom)

2003-12-21

The absorption of a liquid into a rectangular bar of an initially dry porous material that is sealed on all surfaces except the inflow face is analysed in terms of Sharp Front theory. Sharp Front models are developed for both complete and incomplete displacement of air ahead of the advancing wetting front. Experiments are described from which a characteristic capillary potential of the material is obtained by measuring the equilibrium pressure of the air displaced and compressed ahead of the advancing wetting front. Results for the absorption of water and n-heptane by a fired clay brick ceramic suggest that this wetting front capillary pressure (or capillary potential) scales approximately with the surface tension and also that the permeability scales inversely with the liquid viscosity. The pressure of the air trapped in the wetted region is found to be the same as the pressure of the displaced air. For this material the wetting front capillary pressure for water at 20 C is 0.113 MPa, equivalent to a hydraulic tension head of 11.5 m and to a Young-Laplace pore diameter of 2.6 {mu}m. The capillary pressure so measured is apparently a fundamental percolation property of the material that can be interpreted as the air pressure at which liquid phase continuity and unsaturated conductivity both vanish. The method described can be applied generally to porous materials.

Direct measurement of the wetting front capillary pressure in a clay brick ceramic

International Nuclear Information System (INIS)

Ioannou, Ioannis; Hall, Christopher; Wilson, Moira A; Hoff, William D; Carter, Margaret A

2003-01-01

The absorption of a liquid into a rectangular bar of an initially dry porous material that is sealed on all surfaces except the inflow face is analysed in terms of Sharp Front theory. Sharp Front models are developed for both complete and incomplete displacement of air ahead of the advancing wetting front. Experiments are described from which a characteristic capillary potential of the material is obtained by measuring the equilibrium pressure of the air displaced and compressed ahead of the advancing wetting front. Results for the absorption of water and n-heptane by a fired clay brick ceramic suggest that this wetting front capillary pressure (or capillary potential) scales approximately with the surface tension and also that the permeability scales inversely with the liquid viscosity. The pressure of the air trapped in the wetted region is found to be the same as the pressure of the displaced air. For this material the wetting front capillary pressure for water at 20 C is 0.113 MPa, equivalent to a hydraulic tension head of 11.5 m and to a Young-Laplace pore diameter of 2.6 μm. The capillary pressure so measured is apparently a fundamental percolation property of the material that can be interpreted as the air pressure at which liquid phase continuity and unsaturated conductivity both vanish. The method described can be applied generally to porous materials

Understanding the Front-end of Large-scale Engineering Programs

DEFF Research Database (Denmark)

Lucae, Sebastian; Rebentisch, Eric; Oehmen, Josef

2014-01-01

Large engineering programs like sociotechnical infrastructure constructions of airports, plant constructions, or the development of radically innovative, high-tech industrial products such as electric vehicles or aircraft are affected by a number of serious risks, and subsequently commonly suffer...... from large cost overruns. Significant problems in program execution can be traced back to practices performed, or more frequently not performed, in the so-called “fuzzy front end” of the program. The lack of sufficient and effective efforts in the early stages of a program can result in unstable......, unclear and incomplete requirements, unclear roles and responsibilities within the program organization, insufficient planning, and unproductive tensions between program management and systems engineering. This study intends to clarify the importance of up-front planning to improve program performance...

Development of a dedicated front-end electronics for straw tube trackers in the P-bar ANDA experiment

International Nuclear Information System (INIS)

Przyborowski, D.; Fiutowski, T.; Idzik, M.; Swientek, K.; Terlecki, P.; Tokarz, J.; Kajetanowicz, M.; Korcyl, G.; Salabura, P.; Smyrski, J.; Strzempek, P.

2016-01-01

The design and tests of front-end electronics for straw tube trackers in the P-bar ANDA experiment at FAIR are presented. The challenges for the front-end electronics, comprising operation at high counting rate up to 1 MHz per straw tube, are discussed and the proposed architecture comprising a switched gain charge sensitive preamplifier (CSP), a pole-zero cancellation circuit (PZC), a second order variable peaking time shaper, a trimming ion tail cancellation circuit, and a baseline holder (BLH), is described. The front-end provides an analogue output and a discriminator with LVDS differential driver for the Time-of-Arrival (ToA) and Time-over-Threshold (ToT) measurements. A prototype readout ASIC featuring four channels was fabricated in 0.35 μm CMOS technology consuming 15.5 mW (analog part) and 12 mW (LVDS) per channel. The results of measurements of peaking time (25–67 ns), gain, noise (ENC 800–2500 el. for various gains), time walk and jitter are presented as well as the first results obtained with prototype straw tubes connected.

Topology optimization of front metallization patterns for solar cells

NARCIS (Netherlands)

Gupta, D.K.; Langelaar, M.; Barink, M.; Keulen, F. van

2015-01-01

This paper presents the application of topology optimization (TO) for designing the front electrode patterns for solar cells. Improving the front electrode design is one of the approaches to improve the performance of the solar cells. It serves to produce the voltage distribution for the front

Ocean Thermal Extractable Energy Visualization

Energy Technology Data Exchange (ETDEWEB)

Ascari, Matthew [Lockheed Martin Corporation, Bethesda, MD (United States)

2012-10-28

The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world’s ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today’s state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources.

Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots.

Science.gov (United States)

Queiroz, Nuno; Humphries, Nicolas E; Mucientes, Gonzalo; Hammerschlag, Neil; Lima, Fernando P; Scales, Kylie L; Miller, Peter I; Sousa, Lara L; Seabra, Rui; Sims, David W

2016-02-09

Overfishing is arguably the greatest ecological threat facing the oceans, yet catches of many highly migratory fishes including oceanic sharks remain largely unregulated with poor monitoring and data reporting. Oceanic shark conservation is hampered by basic knowledge gaps about where sharks aggregate across population ranges and precisely where they overlap with fishers. Using satellite tracking data from six shark species across the North Atlantic, we show that pelagic sharks occupy predictable habitat hotspots of high space use. Movement modeling showed sharks preferred habitats characterized by strong sea surface-temperature gradients (fronts) over other available habitats. However, simultaneous Global Positioning System (GPS) tracking of the entire Spanish and Portuguese longline-vessel fishing fleets show an 80% overlap of fished areas with hotspots, potentially increasing shark susceptibility to fishing exploitation. Regions of high overlap between oceanic tagged sharks and longliners included the North Atlantic Current/Labrador Current convergence zone and the Mid-Atlantic Ridge southwest of the Azores. In these main regions, and subareas within them, shark/vessel co-occurrence was spatially and temporally persistent between years, highlighting how broadly the fishing exploitation efficiently "tracks" oceanic sharks within their space-use hotspots year-round. Given this intense focus of longliners on shark hotspots, our study argues the need for international catch limits for pelagic sharks and identifies a future role of combining fine-scale fish and vessel telemetry to inform the ocean-scale management of fisheries.

Evaluating the role of fronts in habitat overlaps between cold and warm water species in the western North Pacific: A proof of concept

Science.gov (United States)

Mugo, Robinson M.; Saitoh, Sei-Ichi; Takahashi, Fumihiro; Nihira, Akira; Kuroyama, Tadaaki

2014-09-01

Cold- and warm-water species' fishing grounds show a spatial synchrony around fronts in the western North Pacific (WNP). However, it is not yet clear whether a front (thermal, salinity or chlorophyll) acts as an absolute barrier to fish migration on either side or its structure allows interaction of species with different physiological requirements. Our objective was to assess potential areas of overlap between cold- and warm-water species using probabilities of presence derived from fishery datasets and remotely sensed environment data in the Kuroshio-Oyashio region in the WNP. Fishery data comprised skipjack tuna (Katsuwonus pelamis) fishing locations and proxy presences (derived from fishing night light images) for neon flying squid (Ommastrephes bartrami) and Pacific saury (Cololabis saira). Monthly (August-November) satellite remotely sensed sea-surface temperature, chlorophyll-a and sea-surface height anomaly images were used as environment data. Maximum entropy (MaxEnt) models were used to determine probabilities of presence (PoP) for each set of fishery and environment data for the area 35-45°N and 140-160°E. Maps of both sets of PoPs were compared and areas of overlap identified using a combined probability map. Results indicated that areas of spatial overlap existed among the species habitats, which gradually widened from September to November. The reasons for these overlaps include the presence of strong thermal/ocean-color gradients between cold Oyashio and warm Kuroshio waters, and also the presence of the sub-arctic front. Due to the high abundance of food along frontal zones, the species use the fronts as foraging grounds while confining within physiologically tolerable waters on either side of the front. The interaction zone around the front points to areas that might be accessible to both species for foraging, which suggests intense prey-predator interaction zones.

Communicating healthier food choice : food composition data, front-of-pack nutrition labelling and health claims.

OpenAIRE

Hodgkins, Charo E.

2016-01-01

Background: Food composition data, front-of-pack nutrition labelling and nutrition and health claims have an important role to play in the development of appropriate policy, regulation and public health interventions ultimately aimed at reducing the burden of diet-related chronic disease. The overarching aim of this thesis is to explore whether the communication of healthier food choice through front-of-pack (FOP) nutrition labelling and health claims can be enhanced by the development of con...

Connecting Coastal Communities with Ocean Science: A Look at Ocean Sense and the Inclusion of Place-based Indigenous Knowledge

Science.gov (United States)

McLean, M. A.; Brown, J.; Hoeberechts, M.

2016-02-01

Ocean Networks Canada (ONC), an initiative of the University of Victoria, develops, operates, and maintains cabled ocean observatory systems. Technologies developed on the world-leading NEPTUNE and VENUS observatories have been adapted for small coastal installations called "community observatories," which enable community members to directly monitor conditions in the local ocean environment. In 2014, ONC pioneered an innovative educational program, Ocean Sense: Local observations, global connections, which introduces students and teachers to the technologies installed on community observatories. The program introduces middle and high school students to research methods in biology, oceanography and ocean engineering through hands-on activities. Ocean Sense includes a variety of resources and opportunities to excite students and spark curiosity about the ocean environment. The program encourages students to connect their local observations to global ocean processes and the observations of students in other geographic regions. The connection to place and local relevance of the program is further enhanced through an emphasis on Indigenous and place-based knowledge. ONC is working with coastal Indigenous communities in a collaborative process to include local knowledge, culture, and language in Ocean Sense materials. For this process to meaningful and culturally appropriate, ONC is relying on the guidance and oversight of Indigenous community educators and knowledge holders. Ocean Sense also includes opportunities for Indigenous youth and teachers in remote communities to connect in person, including an annual Ocean Science Symposium and professional development events for teachers. Building a program which embraces multiple perspectives is effective both in making ocean science more relevant to Indigenous students and in linking Indigenous knowledge and place-based knowledge to ocean science.

Ocean impact on Nioghalvfjerdsfjorden Glacier, Northeast Greenland

Science.gov (United States)

Schaffer, Janin; Kanzow, Torsten; von Appen, Wilken-Jon; Mayer, Christoph

2017-04-01

The ocean plays an important role in modulating the mass balance of the Greenland Ice Sheet by delivering heat to the marine-terminating outlet glaciers around Greenland. The largest of three outlet glaciers draining the Northeast Greenland Ice Stream is Nioghalvfjerdsfjorden Glacier (also referred to as 79 North Glacier). Historic observations showed that warm waters of Atlantic origin are present in the subglacial cavity below the 80 km long floating ice tongue of the Nioghalvfjerdsfjorden Glacier and cause strong basal melt at the grounding line, but to date it has been unknown how those warm water enter the cavity. In order to understand how Atlantic origin waters carry heat into the subglacial cavity beneath Nioghalvfjerdsfjorden Glacier, we performed bathymetric, hydrographic, and velocity observations in the vicinity of the main glacier calving front aboard RV Polarstern in summer 2016. The bathymetric multibeam data shows a 500 m deep and 2 km narrow passage downstream of a 310 m deep sill. This turned out to be the only location deep enough for an exchange of Atlantic waters between the glacier cavity and the continental shelf. Hydrographic and velocity measurements revealed a density driven plume in the vicinity of the glacier calving front causing a rapid flow of waters of Atlantic origin warmer 1°C into the subglacial cavity through the 500 m deep passage. In addition, glacially modified waters flow out of the glacier cavity below the 80 m deep ice base. In the vicinity of the glacier, the glacially modified waters form a distinct mixed layer situated above the Atlantic waters and below the ambient Polar water. At greater distances from the glacier this layer is eroded by lateral mixing with ambient water. Based on our observations we will present an estimate of the ocean heat transport into the subglacial cavity. In comparison with historic observations we find an increase in Atlantic water temperatures throughout the last 20 years. The resulting

The upgraded CDF front end electronics for calorimetry

Energy Technology Data Exchange (ETDEWEB)

Drake, G.; Frei, D.; Hahn, S.R.; Nelson, C.A.; Segler, S.L.; Stuermer, W.

1991-11-01

The front end electronics used in the calorimetry of the CDF detector has been upgraded to meet system requirements for higher expected luminosity. A fast digitizer utilizing a 2 {mu}Sec, 16 bit ADC has been designed and built. Improvements to the front end trigger circuitry have been implemented, including the production of 900 new front end modules. Operational experience with the previous system is presented, with discussion of the problems and performance goals.

The upgraded CDF front end electronics for calorimetry

International Nuclear Information System (INIS)

Drake, G.; Frei, D.; Hahn, S.R.; Nelson, C.A.; Segler, S.L.; Stuermer, W.

1991-11-01

The front end electronics used in the calorimetry of the CDF detector has been upgraded to meet system requirements for higher expected luminosity. A fast digitizer utilizing a 2 μSec, 16 bit ADC has been designed and built. Improvements to the front end trigger circuitry have been implemented, including the production of 900 new front end modules. Operational experience with the previous system is presented, with discussion of the problems and performance goals

Trans Ocean Gas CNG transportation development plan

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-11-01

Liquefied natural gas (LNG) transportation is on the rise due to increased global demand for natural gas. However, the challenge of transporting LNG lies in finding suitable locations for import terminals. Compressed natural gas (CNG) transportation offers an alternative method for transporting stranded natural gas to existing markets and for creating new natural gas markets not practical for LNG or pipelines. The founder of Trans Ocean Gas Inc. (TOG) modified an existing fibre reinforced plastic (FRP) pressure vessel technology to safely store CNG on a ship. The newly developed containment system has proven to overcome all the deficiencies of steel-based systems. TOG patented the containment system and will license its use to owners of stranded gas and shipping service providers around the world. Financial support is needed to perform verification testing and for regulatory approval. The CNG systems will be built and assembled throughout facilities in Atlantic Canada. 2 tabs., 3 figs.

Our Changing Oceans: All about Ocean Acidification

International Nuclear Information System (INIS)

Rickwood, Peter

2013-01-01

The consequences of ocean acidification are global in scale. More research into ocean acidification and its consequences is needed. It is already known, for example, that there are regional differences in the vulnerability of fisheries to acidification. The combination of other factors, such as global warming, the destruction of habitats, overfishing and pollution, need to be taken into account when developing strategies to increase the marine environment’s resilience. Among steps that can be taken to reduce the impact is better protection of marine coastal ecosystems, such as mangrove swamps and seagrass meadows, which will help protect fisheries. This recommendation was one of the conclusions of a three-day workshop attended by economists and scientists and organized by the IAEA and the Centre Scientifique de Monaco in November 2012. In their recommendations the workshop also stressed that the impact of increasing ocean acidity must be taken into account in the management of fisheries, particularly where seafood is a main dietary source

Through the EU's Back and Front Doors

DEFF Research Database (Denmark)

Adler-Nissen, Rebecca

2015-01-01

Through the EU's front- and backdoors: The selective Danish and Norwegian approaches in the Area of Freedom, Security and Justice Rebecca Adler-Nissen......Through the EU's front- and backdoors: The selective Danish and Norwegian approaches in the Area of Freedom, Security and Justice Rebecca Adler-Nissen...

Photon polarization tensor in the light front field theory at zero and finite temperatures

International Nuclear Information System (INIS)

Silva, Charles da Rocha; Perez, Silvana; Strauss, Stefan

2012-01-01

Full text: In recent years, light front quantized field theories have been successfully generalized to finite temperature. The light front frame was introduced by Dirac , and the quantization of field theories on the null-plane has found applications in many branches of physics. In order to obtain the thermal contribution, we consider the hard thermal loop approximation. This technique was developed by Braaten and Pisarski for the thermal quantum field theory at equal times and is particularly useful to extract the leading thermal contributions to the amplitudes in perturbative quantum field theories. In this work, we consider the light front quantum electrodynamics in (3+1) dimensions and evaluate the photon polarization tensor at one loop for both zero and finite temperatures. In the first case, we apply the dimensional regularization method to extract the finite contribution and find the transverse structure for the amplitude in terms of the light front coordinates. The result agrees with one-loop covariant calculation. For the thermal corrections, we generalize the hard thermal loop approximation to the light front and calculate the dominant temperature contribution to the polarization tensor, consistent with the Ward identity. In both zero as well as finite temperature calculations, we use the oblique light front coordinates. (author)

Gasdynamics of H II regions. V. The interaction of weak R ionization fronts with dense clouds

Energy Technology Data Exchange (ETDEWEB)

Tenorio-Tagle, G; Bedijn, P J

1981-06-01

The interaction of weak R-type ionization fronts with a density enhancement is calculated numerically as a function of time within the framework of the champagne model of the evolution of H II regions. Calculations are performed under the assumption of plane-parallel geometry for various relative densities of the cloud in which the exciting star is formed and a second cloud with which an ionization front from the first cloud interacts. The supersonic ionization front representing the outer boundary of an H II region experiencing the champagne phase is found to either evolve into a D-type front or remain of type R, depending on the absolute number of photons leaving the H II region that undergoes the champagne phase. Recombinations in the ionized gas eventually slow the ionization front, however photon fluxes allow it to speed up again, resulting in oscillatory propagation of the front. Front-cloud interactions are also shown to lead to the development of a backward-facing shock, a forward-facing shock, and a density maximum in the ionized gas. The results can be used to explain the origin of bright rims in H II regions.

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Science.gov (United States)

Lizotte, Martine; Levasseur, Maurice; Law, Cliff S.; Walker, Carolyn F.; Safi, Karl A.; Marriner, Andrew; Kiene, Ronald P.

2017-11-01

The oceanic frontal region above the Chatham Rise east of New Zealand was investigated during the late austral summer season in February and March 2012. Despite its potential importance as a source of marine-originating and climate-relevant compounds, such as dimethyl sulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP), little is known of the processes fuelling the reservoirs of these sulfur (S) compounds in the water masses bordering the subtropical front (STF). This study focused on two opposing short-term fates of DMSP-S following its uptake by microbial organisms (either its conversion into DMS or its assimilation into bacterial biomass) and has not considered dissolved non-volatile degradation products. Sampling took place in three phytoplankton blooms (B1, B2, and B3) with B1 and B3 occurring in relatively nitrate-rich, dinoflagellate-dominated subantarctic waters, and B2 occurring in nitrate-poor subtropical waters dominated by coccolithophores. Concentrations of total DMSP (DMSPt) and DMS were high across the region, up to 160 and 14.5 nmol L-1, respectively. Pools of DMSPt showed a strong association with overall phytoplankton biomass proxied by chlorophyll a (rs = 0.83) likely because of the persistent dominance of dinoflagellates and coccolithophores, both DMSP-rich taxa. Heterotrophic microbes displayed low S assimilation from DMSP (less than 5 %) likely because their S requirements were fulfilled by high DMSP availability. Rates of bacterial protein synthesis were significantly correlated with concentrations of dissolved DMSP (DMSPd, rs = 0.86) as well as with the microbial conversion efficiency of DMSPd into DMS (DMS yield, rs = 0.84). Estimates of the potential contribution of microbially mediated rates of DMS production (0.1-27 nmol L-1 day-1) to the near-surface concentrations of DMS suggest that bacteria alone could not have sustained DMS pools at most stations, indicating an important role for phytoplankton-mediated DMS

Bibliometric analysis of acupuncture research fronts and their ...

African Journals Online (AJOL)

Bibliometric analysis of acupuncture research fronts and their worldwide ... This study chronologically examined the changing features and research fronts of ... from the Science Citation Index Expanded and Social Science Citation Index.

Collaborative Oceanographic Research Opportunities with Schmidt Ocean Institute

Science.gov (United States)

Zykov, V.

2014-12-01

Schmidt Ocean Institute (http://www.schmidtocean.org/) was founded by Dr. Eric Schmidt and Wendy Schmidt in 2009 to support frontier oceanographic research and exploration to expand the understanding of the world's oceans through technological advancement, intelligent, data-rich observation and analysis, and open sharing of information. Schmidt Ocean Institute operates a state-of-the-art globally capable research vessel Falkor (http://www.schmidtocean.org/story/show/47). After two years of scientific operations in the Atlantic Ocean, Gulf of Mexico, Caribbean, Eastern and Central Pacific, R/V Falkor is now preparing to support research in the Western Pacific and Eastern Indian Oceans in 2015 and 2016. As part of the long term research program development for Schmidt Ocean Institute, we aim to identify initiatives and projects that demonstrate strong alignment with our strategic interests. We focus on scientific opportunities that highlight effective use of innovative technologies to better understand the oceans, such as, for example, research enabled with remotely operated and autonomous vehicles, acoustics, in-situ sensing, telepresence, etc. Our technology-first approach to ocean science gave rise to infrastructure development initiatives, such as the development of a new full ocean depth Hybrid Remotely Operated Vehicle, new 6000m scientific Autonomous Underwater Vehicle, live HD video streaming from the ship to YouTube, shipboard high performance supercomputing, etc. We also support projects focusing on oceanographic technology research and development onboard R/V Falkor. We provide our collaborators with access to all of R/V Falkor's facilities and instrumentation in exchange for a commitment to make the resulting scientific data openly available to the international oceanographic community. This presentation aims to expand awareness about the interests and capabilities of Schmidt Ocean Institute and R/V Falkor among our scientific audiences and further

Time-delayed fronts from biased random walks

International Nuclear Information System (INIS)

Fort, Joaquim; Pujol, Toni

2007-01-01

We generalize a previous model of time-delayed reaction-diffusion fronts (Fort and Mendez 1999 Phys. Rev. Lett. 82 867) to allow for a bias in the microscopic random walk of particles or individuals. We also present a second model which takes the time order of events (diffusion and reproduction) into account. As an example, we apply them to the human invasion front across the USA in the 19th century. The corrections relative to the previous model are substantial. Our results are relevant to physical and biological systems with anisotropic fronts, including particle diffusion in disordered lattices, population invasions, the spread of epidemics, etc

Advance of Wetting Front in Silt Loam Soil

Directory of Open Access Journals (Sweden)

Mohamed Mahmood

2013-04-01

Full Text Available Under drip irrigation , the plant's root is concentrated inside the wetted bulb (region. Thus, the development of these roots and the plant production are greatly affected by the wetting pattern. Therefore, the wetting pattern of soil under drip irrigation must be taken into consideration in the design of drip irrigation system for both single dripping source or multi-overlapping wetting patterns of dripping water sources.2The aim of this study is to evaluate the effect of initial water content of the soil and spacing between two adjacent dripping sources with different flow rate on the movement of the wetting front.This study included 16 tests for monitoring the advancement of the wetting front with time during and after the water application phase. The water advance and water distribution measurement are carried out for two cases of the soil profile: for the first case with initial volumetric water content of 4.08% and for the second case with initial volumetric water content of 12.24%. Two spacing between the emitter were tested 25cm and 50 cm using application flow rates of 0.606, 1.212, 1.818, and 2.424 cm3 /min/cm to show the combined effect of spacing and flow rate on the performance of two adjacent emitter.The study proposed a method for determining the spacing between the two emitting sources , the water application rate and watering time. The proposed method depends on a wetted zone whose depth is equal to the root zone depth with a values equals to the maximum vertical advance of the wetting front underneath the drip line at time when this depth is equal to the depth of wetting at mid­point between the drip line. the study revealed that both the vertical water advance in soil underneath the emitter and the horizontal advance of the wetting front is larger than those in the case of single emitter.Furthermore, the vertical water advance increases with the decrease spacing between the two drip lines. Also, the horizontal advance of the

Ocean-atmosphere coupled climate model development at SAWS: description and diagnosis

CSIR Research Space (South Africa)

Beraki, A

2011-09-01

Full Text Available This paper introduces the South African Weather Service's coupled ocean-atmosphere model. The paper also demonstrates the advances made in configuring an operational coupled ocean-atmosphere model in South Africa for seasonal forecast production...

The Impact of Ocean Acidification on Reproduction, Early Development and Settlement of Marine Organisms

Directory of Open Access Journals (Sweden)

Elizabeth A. Bailey

2011-11-01

Full Text Available Predicting the impact of warming and acidifying on oceans on the early development life history stages of invertebrates although difficult, is essential in order to anticipate the severity and consequences of future climate change. This review summarises the current literature and meta-analyses on the early life-history stages of invertebrates including fertilisation, larval development and the implications for dispersal and settlement of populations. Although fertilisation appears robust to near future predictions of ocean acidification, larval development is much more vulnerable and across invertebrate groups, evidence indicates that the impacts may be severe. This is especially for those many marine organisms which start to calcify in their larval and/or juvenile stages. Species-specificity and variability in responses and current gaps in the literature are highlighted, including the need for studies to investigate the total effects of climate change including the synergistic impact of temperature, and the need for long-term multigenerational experiments to determine whether vulnerable invertebrate species have the capacity to adapt to elevations in atmospheric CO2 over the next century.

The 'spontaneous' acoustic emission of the shock front in a perfect fluid: solving a riddle

International Nuclear Information System (INIS)

Brun, Louis

2013-06-01

In the fifties, S. D'yakov discovered that theory allows for suitable EOS shock fronts to emit acoustic waves 'spontaneously'. Section 90 of Fluid Mechanics of Landau and Lifshitz, 2. Ed., deals with the phenomenon, leaving it unexplained. This open question was chosen to introduce a monograph in progress about 'the shock front in the perfect fluid'. The novelty of our approach consists in having the phenomenon generated - which means it is non-spontaneous -- from an appropriate solicitation of the front and studying its development analytically. The non classical source and mechanism of the emission are thus brought to light. (author)

Characteristic wave fronts in magnetohydrodynamics

International Nuclear Information System (INIS)

Menon, V.V.; Sharma, V.D.

1981-01-01

The influence of magnetic field on the process of steepening or flattening of the characteristic wave fronts in a plane and cylindrically symmetric motion of an ideal plasma is investigated. This aspect of the problem has not been considered until now. Remarkable differences between plane, cylindrical diverging, and cylindrical converging waves are discovered. The discontinuity in the velocity gradient at the wave front is shown to satisfy a Bernoulli-type equation. The discussion of the solutions of such equations reported in the literature is shown to be incomplete, and three general theorems are established. 18 refs

Light-front nuclear shell-model

International Nuclear Information System (INIS)

Johnson, M.B.

1990-01-01

I examine the effects of nuclear structure on high-energy, high-momentum transfer processes, specifically the EMC effect. For pedagogical reasons, a fictitious but simple two-body system consisting of two equal-mass particles interacting in a harmonic oscillator potential has been chosen. For this toy nucleus, I utilize a widely-used link between instant-form and light-front dynamics, formulating nuclear structure and deep-inelastic scattering consistently in the laboratory system. Binding effects are compared within conventional instant-form and light-front dynamical frameworks, with appreciable differences being found in the two cases. 20 refs

Ocean surface partitioning strategies using ocean colour remote Sensing: A review

Science.gov (United States)

Krug, Lilian Anne; Platt, Trevor; Sathyendranath, Shubha; Barbosa, Ana B.

2017-06-01

The ocean surface is organized into regions with distinct properties reflecting the complexity of interactions between environmental forcing and biological responses. The delineation of these functional units, each with unique, homogeneous properties and underlying ecosystem structure and dynamics, can be defined as ocean surface partitioning. The main purposes and applications of ocean partitioning include the evaluation of particular marine environments; generation of more accurate satellite ocean colour products; assimilation of data into biogeochemical and climate models; and establishment of ecosystem-based management practices. This paper reviews the diverse approaches implemented for ocean surface partition into functional units, using ocean colour remote sensing (OCRS) data, including their purposes, criteria, methods and scales. OCRS offers a synoptic, high spatial-temporal resolution, multi-decadal coverage of bio-optical properties, relevant to the applications and value of ocean surface partitioning. In combination with other biotic and/or abiotic data, OCRS-derived data (e.g., chlorophyll-a, optical properties) provide a broad and varied source of information that can be analysed using different delineation methods derived from subjective, expert-based to unsupervised learning approaches (e.g., cluster, fuzzy and empirical orthogonal function analyses). Partition schemes are applied at global to mesoscale spatial coverage, with static (time-invariant) or dynamic (time-varying) representations. A case study, the highly heterogeneous area off SW Iberian Peninsula (NE Atlantic), illustrates how the selection of spatial coverage and temporal representation affects the discrimination of distinct environmental drivers of phytoplankton variability. Advances in operational oceanography and in the subject area of satellite ocean colour, including development of new sensors, algorithms and products, are among the potential benefits from extended use, scope and

Development of QC Procedures for Ocean Data Obtained by National Research Projects of Korea

Science.gov (United States)

Kim, S. D.; Park, H. M.

2017-12-01

To establish data management system for ocean data obtained by national research projects of Ministry of Oceans and Fisheries of Korea, KIOST conducted standardization and development of QC procedures. After reviewing and analyzing the existing international and domestic ocean-data standards and QC procedures, the draft version of standards and QC procedures were prepared. The proposed standards and QC procedures were reviewed and revised by experts in the field of oceanography and academic societies several times. A technical report on the standards of 25 data items and 12 QC procedures for physical, chemical, biological and geological data items. The QC procedure for temperature and salinity data was set up by referring the manuals published by GTSPP, ARGO and IOOS QARTOD. It consists of 16 QC tests applicable for vertical profile data and time series data obtained in real-time mode and delay mode. Three regional range tests to inspect annual, seasonal and monthly variations were included in the procedure. Three programs were developed to calculate and provide upper limit and lower limit of temperature and salinity at depth from 0 to 1550m. TS data of World Ocean Database, ARGO, GTSPP and in-house data of KIOST were analysed statistically to calculate regional limit of Northwest Pacific area. Based on statistical analysis, the programs calculate regional ranges using mean and standard deviation at 3 kind of grid systems (3° grid, 1° grid and 0.5° grid) and provide recommendation. The QC procedures for 12 data items were set up during 1st phase of national program for data management (2012-2015) and are being applied to national research projects practically at 2nd phase (2016-2019). The QC procedures will be revised by reviewing the result of QC application when the 2nd phase of data management programs is completed.

Oceanic Platform of the Canary Islands: an ocean testbed for ocean energy converters

Science.gov (United States)

González, Javier; Hernández-Brito, Joaquín.; Llinás, Octavio

2010-05-01

The Oceanic Platform of the Canary Islands (PLOCAN) is a Governmental Consortium aimed to build and operate an off-shore infrastructure to facilitate the deep sea research and speed up the technology associated. This Consortium is overseen by the Spanish Ministry of Science and Innovation and the Canarian Agency for Research and Innovation. The infrastructure consists of an oceanic platform located in an area with depths between 50-100 meters, close to the continental slope and four kilometers off the coast of Gran Canaria, in the archipelago of the Canary Islands. The process of construction will start during the first months of 2010 and is expected to be finished in mid-year 2011. PLOCAN serves five strategic lines: an integral observatory able to explore from the deep ocean to the atmosphere, an ocean technology testbed, a base for underwater vehicles, an innovation platform and a highly specialized training centre. Ocean energy is a suitable source to contribute the limited mix-energy conformed in the archipelago of the Canary Islands with a total population around 2 million people unequally distributed in seven islands. Islands of Gran Canaria and Tenerife support the 80% of the total population with 800.000 people each. PLOCAN will contribute to develop the ocean energy sector establishing a marine testbed allowing prototypes testing at sea under a meticulous monitoring network provided by the integral observatory, generating valuable information to developers. Reducing costs throughout an integral project management is an essential objective to be reach, providing services such as transportation, customs and administrative permits. Ocean surface for testing activities is around 8 km2 with a depth going from 50 to 100 meters, 4km off the coast. Selected areas for testing have off-shore wind power conditions around 500-600 W/m2 and wave power conditions around 6 kW/m in the East coast and 10 kW/m in the North coast. Marine currents in the Canary Islands are

Biomechanics of front and back squat exercises

Science.gov (United States)

Braidot, A. A.; Brusa, M. H.; Lestussi, F. E.; Parera, G. P.

2007-11-01

Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee. In previous anterior cruciate ligament injuries, the mini-squats are generally used, in a knee flexion motion range from 0° to 50° because in this range the shear forces, the tibiofemoral and patellofemoral compression forces decrease related to greater flexion angles. The aim of this work is to make a comparative bidimensional study of the kinematic and dynamic variables of the excecution of the parallel squat exercise with the front and back bar. It is observed in the knee a better development of energy with the front bar, allowing a better muscular exercise with the same load. The mean power absorbed by the hip with the back bar is considerably greater, associated to the speed of the gesture.

Biomechanics of front and back squat exercises

International Nuclear Information System (INIS)

Braidot, A A; Brusa, M H; Lestussi, F E; Parera, G P

2007-01-01

Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee. In previous anterior cruciate ligament injuries, the mini-squats are generally used, in a knee flexion motion range from 0 deg. to 50 deg. because in this range the shear forces, the tibiofemoral and patellofemoral compression forces decrease related to greater flexion angles. The aim of this work is to make a comparative bidimensional study of the kinematic and dynamic variables of the excecution of the parallel squat exercise with the front and back bar. It is observed in the knee a better development of energy with the front bar, allowing a better muscular exercise with the same load. The mean power absorbed by the hip with the back bar is considerably greater, associated to the speed of the gesture

Biomechanics of front and back squat exercises

Energy Technology Data Exchange (ETDEWEB)

Braidot, A A [Laboratorio de Biomecanica FI-UNER. Ruta 11 Km 10 Oro Verde Entre Rios (Argentina); Brusa, M H [Laboratorio de Biomecanica FI-UNER. Ruta 11 Km 10 Oro Verde Entre Rios (Argentina); Lestussi, F E [Laboratorio de Biomecanica FI-UNER. Ruta 11 Km 10 Oro Verde Entre Rios (Argentina); Parera, G P [Licenciatura en KinesiologIa y FisiatrIa Universidad Abierta Interamericana. Sede Regional Rosario (Argentina)

2007-11-15

Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee. In previous anterior cruciate ligament injuries, the mini-squats are generally used, in a knee flexion motion range from 0 deg. to 50 deg. because in this range the shear forces, the tibiofemoral and patellofemoral compression forces decrease related to greater flexion angles. The aim of this work is to make a comparative bidimensional study of the kinematic and dynamic variables of the excecution of the parallel squat exercise with the front and back bar. It is observed in the knee a better development of energy with the front bar, allowing a better muscular exercise with the same load. The mean power absorbed by the hip with the back bar is considerably greater, associated to the speed of the gesture.

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean

International Nuclear Information System (INIS)

Eden, H.F.; Mooers, C.N.K.

1990-06-01

The goal of COPS is to couple a program of regular observations to numerical models, through techniques of data assimilation, in order to provide a predictive capability for the US coastal ocean including the Great Lakes, estuaries, and the entire Exclusive Economic Zone (EEZ). The objectives of the program include: determining the predictability of the coastal ocean and the processes that govern the predictability; developing efficient prediction systems for the coastal ocean based on the assimilation of real-time observations into numerical models; and coupling the predictive systems for the physical behavior of the coastal ocean to predictive systems for biological, chemical, and geological processes to achieve an interdisciplinary capability. COPS will provide the basis for effective monitoring and prediction of coastal ocean conditions by optimizing the use of increased scientific understanding, improved observations, advanced computer models, and computer graphics to make the best possible estimates of sea level, currents, temperatures, salinities, and other properties of entire coastal regions

Seasonality in ocean microbial communities.

Science.gov (United States)

Giovannoni, Stephen J; Vergin, Kevin L

2012-02-10

Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

Progress with the SNS front-end systems

International Nuclear Information System (INIS)

Keller, R.; Abraham, W.; Ayers, J.J.; Cheng, D.W.; Cull, P.; DiGennaro, R.; Doolittle, L.; Gough, R.A.; Greer, J.B.; Hoff, M.D.; Leung, K.N.; Lewis, S.; Lionberger, C.; MacGill, R.; Minamihara, Y.; Monroy, M.; Oshatz, D.; Pruyn, J.; Ratti, A.; Reijonen, J.; Schenkel, T.; Staples, J.W.; Syversrud, D.; Thomae, R.; Virostek, S.; Yourd, R.

2001-01-01

The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project have been described in detail elsewhere [1]. They comprise an rf-driven H - ion source, electrostatic LEBT, four-vane RFQ, and an elaborate MEBT. These systems are planned to be delivered to the SNS facility in Oak Ridge in June 2002. This paper discusses the latest design features, the status of development work, component fabrication and procurements, and experimental results with the first commissioned beamline elements

Designing Tools for Ocean Exploration. Galapagos Rifts Expedition--Grades 9-12. Overview: Ocean Exploration.

Science.gov (United States)

National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

This activity teaches about the complexity of ocean exploration, the technological applications and capabilities required for ocean exploration, the importance of teamwork in scientific research projects, and developing abilities necessary to do scientific inquiry. The activity provides learning objectives, a list of needed materials, key…

Finite-time barriers to reaction front propagation

Science.gov (United States)

Locke, Rory; Mahoney, John; Mitchell, Kevin

2015-11-01

Front propagation in advection-reaction-diffusion systems gives rise to rich geometric patterns. It has been shown for time-independent and time-periodic fluid flows that invariant manifolds, termed burning invariant manifolds (BIMs), serve as one-sided dynamical barriers to the propagation of reaction front. More recently, theoretical work has suggested that one-sided barriers, termed burning Lagrangian Coherent structures (bLCSs), exist for fluid velocity data prescribed over a finite time interval, with no assumption on the time-dependence of the flow. In this presentation, we use a time-varying fluid ``wind'' in a double-vortex channel flow to demonstrate that bLCSs form the (locally) most attracting or repelling fronts.

Towards a new curriculum to support the changing front end innovation landscape : Educating engineering students to effectively participate in iterative data-enabled product development processes

NARCIS (Netherlands)

van Kollenburg, J.W.M.; Jeedella, Shawhkat Y.; van Kollenburg, P.A.M.; Kargas, Sotirios

The new generation of Internet of Things product offers exciting opportunities to design and develop highly personal and adaptive products. Engineering students are traditionally not trained to use user data, generated by prototypes, as creative material for ideating the Fuzzy Front End phase of the

Simultaneous fingering, double-diffusive convection, and thermal plumes derived from autocatalytic exothermic reaction fronts

Science.gov (United States)

Eskew, Matthew W.; Harrison, Jason; Simoyi, Reuben H.

2016-11-01

Oxidation reactions of thiourea by chlorite in a Hele-Shaw cell are excitable, autocatalytic, exothermic, and generate a lateral instability upon being triggered by the autocatalyst. Reagent concentrations used to develop convective instabilities delivered a temperature jump at the wave front of 2.1 K. The reaction zone was 2 mm and due to normal cooling after the wave front, this generated a spike rather than the standard well-studied front propagation. The reaction front has solutal and thermal contributions to density changes that act in opposite directions due to the existence of a positive isothermal density change in the reaction. The competition between these effects generates thermal plumes. The fascinating feature of this system is the coexistence of plumes and fingering in the same solution which alternate in frequency as the front propagates, generating hot and cold spots within the Hele-Shaw cell, and subsequently spatiotemporal inhomogeneities. The small ΔT at the wave front generated thermocapillary convection which competed effectively with thermogravitational forces at low Eötvös Numbers. A simplified reaction-diffusion-convection model was derived for the system. Plume formation is heavily dependent on boundary effects from the cell dimensions. This work was supported by Grant No. CHE-1056366 from the NSF and a Research Professor Grant from the University of KwaZulu-Natal.

Optimal back-to-front airplane boarding

Science.gov (United States)

Bachmat, Eitan; Khachaturov, Vassilii; Kuperman, Ran

2013-06-01

The problem of finding an optimal back-to-front airplane boarding policy is explored, using a mathematical model that is related to the 1+1 polynuclear growth model with concave boundary conditions and to causal sets in gravity. We study all airplane configurations and boarding group sizes. Optimal boarding policies for various airplane configurations are presented. Detailed calculations are provided along with simulations that support the main conclusions of the theory. We show that the effectiveness of back-to-front policies undergoes a phase transition when passing from lightly congested airplanes to heavily congested airplanes. The phase transition also affects the nature of the optimal or near-optimal policies. Under what we consider to be realistic conditions, optimal back-to-front policies lead to a modest 8-12% improvement in boarding time over random (no policy) boarding, using two boarding groups. Having more than two groups is not effective.

Optimal back-to-front airplane boarding.

Science.gov (United States)

Bachmat, Eitan; Khachaturov, Vassilii; Kuperman, Ran

2013-06-01

The problem of finding an optimal back-to-front airplane boarding policy is explored, using a mathematical model that is related to the 1+1 polynuclear growth model with concave boundary conditions and to causal sets in gravity. We study all airplane configurations and boarding group sizes. Optimal boarding policies for various airplane configurations are presented. Detailed calculations are provided along with simulations that support the main conclusions of the theory. We show that the effectiveness of back-to-front policies undergoes a phase transition when passing from lightly congested airplanes to heavily congested airplanes. The phase transition also affects the nature of the optimal or near-optimal policies. Under what we consider to be realistic conditions, optimal back-to-front policies lead to a modest 8-12% improvement in boarding time over random (no policy) boarding, using two boarding groups. Having more than two groups is not effective.

75 FR 18778 - Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD

Science.gov (United States)

2010-04-13

...-AA00 Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS... zone on the Atlantic Ocean in the vicinity of Ocean City, Maryland to support the Ocean City Air Show. This action is intended to restrict vessel traffic movement on the Atlantic Ocean to protect mariners...

Navigating a sea of values: Understanding public attitudes toward the ocean and ocean energy resources

Science.gov (United States)

Lilley, Jonathan Charles

In examining ocean values and beliefs, this study investigates the moral and ethical aspects of the relationships that exist between humans and the marine environment. In short, this dissertation explores what the American public thinks of the ocean. The study places a specific focus upon attitudes to ocean energy development. Using both qualitative and quantitative methods, this research: elicits mental models that exist in society regarding the ocean; unearths what philosophies underpin people's attitudes toward the ocean and offshore energy development; assesses whether these views have any bearing on pro-environmental behavior; and gauges support for offshore drilling and offshore wind development. Despite the fact that the ocean is frequently ranked as a second-tier environmental issue, Americans are concerned about the state of the marine environment. Additionally, the data show that lack of knowledge, rather than apathy, prevents people from undertaking pro-environmental action. With regard to philosophical beliefs, Americans hold slightly more nonanthropocentric than anthropocentric views toward the environment. Neither anthropocentrism nor nonanthropocentrism has any real impact on pro-environmental behavior, although nonanthropocentric attitudes reduce support for offshore wind. This research also uncovers two gaps between scientific and public perceptions of offshore wind power with respect to: 1) overall environmental effects; and 2) the size of the resource. Providing better information to the public in the first area may lead to a shift toward offshore wind support among opponents with nonanthropocentric attitudes, and in both areas, is likely to increase offshore wind support.

Hybrid circuit prototypes for the CMS Tracker upgrade front-end electronics

International Nuclear Information System (INIS)

Blanchot, G; Honma, A; Kovacs, M; Braga, D; Raymond, M

2013-01-01

New high-density interconnect hybrid circuits are under development for the CMS tracker modules at the HL-LHC. These hybrids will provide module connectivity between flip-chip front-end ASICs, strip sensors and a service board for the data transmission and powering. Rigid organic-based substrate prototypes and also a flexible hybrid design have been built, containing up to eight front-end flip chip ASICs. A description of the function of the hybrid circuit in the tracker, the first prototype designs, results of some electrical and mechanical properties from the prototypes, and examples of the integration of the hybrids into detector modules are presented

Propagation study of the ionization fronts in a gas subject to an impulse field

International Nuclear Information System (INIS)

Gayraud, Francois.

1978-01-01

We study the formation of a discharge in nitrogen and in nitrogen-methane mixtures (2,5% to 50% of methane) for pressures of several hundred torr and for electric-field-to-pressure ratio values between 110 and 150 V.cm -1 .torr -1 . The development of the discharge is observed by means of streak camera with a temporal resolution of 400 ps. The analysis of the recording allows to characterise several phases in the ionization fronts development. We give the variation of the speed of the fronts in function of the proportion of methane and of the ratio E/p. We explicit a streamer propagation model, based on the hypothesis that the plasma channel behind the front is assimilable to a perfect conductor. Thus, we obtain analytic expressions of the length and the speed of the streamer. The values obtained from these relations are in excellent agreement with the values measured [fr

Adaptive RF front-ends for hand-held applications

CERN Document Server

van Bezooijen, Andre; van Roermund, Arthur

2010-01-01

The RF front-end - antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable. ""Adaptive RF Front-Ends for Hand-Held Applications"" presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control,

Determination of cut front position in laser cutting

Science.gov (United States)

Pereira, M.; Thombansen, U.

2016-07-01

Laser cutting has a huge importance to manufacturing industry. Laser cutting machines operate with fixed technological parameters and this does not guarantee the best productivity. The adjustment of the cutting parameters during operation can improve the machine performance. Based on a coaxial measuring device it is possible to identify the cut front position during the cutting process. This paper describes the data analysis approach used to determine the cut front position for different feed rates. The cut front position was determined with good resolution, but improvements are needed to make the whole process more stable.

Development of wavelet-ANN models to predict water quality parameters in Hilo Bay, Pacific Ocean.

Science.gov (United States)

Alizadeh, Mohamad Javad; Kavianpour, Mohamad Reza

2015-09-15

The main objective of this study is to apply artificial neural network (ANN) and wavelet-neural network (WNN) models for predicting a variety of ocean water quality parameters. In this regard, several water quality parameters in Hilo Bay, Pacific Ocean, are taken under consideration. Different combinations of water quality parameters are applied as input variables to predict daily values of salinity, temperature and DO as well as hourly values of DO. The results demonstrate that the WNN models are superior to the ANN models. Also, the hourly models developed for DO prediction outperform the daily models of DO. For the daily models, the most accurate model has R equal to 0.96, while for the hourly model it reaches up to 0.98. Overall, the results show the ability of the model to monitor the ocean parameters, in condition with missing data, or when regular measurement and monitoring are impossible. Copyright © 2015 Elsevier Ltd. All rights reserved.

QCD Phenomenology and Light-Front Wave Functions

International Nuclear Information System (INIS)

Brodsky, St.J.

2001-01-01

A natural calculus for describing the bound-state structure of relativistic composite systems in quantum field theory is the light-front Fock expansion which encodes the properties of a hadrons in terms of a set of frame-independent n-particle wave functions. Light-front quantization in the doubly-transverse light-cone gauge has a number of remarkable advantages, including explicit unitarity, a physical Fock expansion, the absence of ghost degrees of freedom, and the decoupling properties needed to prove factorization theorems in high momentum transfer inclusive and exclusive reactions. A number of applications are discussed in these lectures, including semileptonic B decays, two-photon exclusive reactions, diffractive dissociation into jets, and deeply virtual Compton scattering. The relation of the intrinsic sea to the light-front wave functions is discussed. Light-front quantization can also be used in the Hamiltonian form to construct an event generator for high energy physics reactions at the amplitude level. The light-cone partition function, summed over exponentially-weighted light-cone energies, has simple boost properties which may be useful for studies in heavy ion collisions. I also review recent work which shows that the structure functions measured in deep inelastic lepton scattering are affected by final-state rescattering, thus modifying their connection to light-front probability distributions. In particular, the shadowing of nuclear structure functions is due to destructive interference effects from leading-twist diffraction of the virtual photon, physics not included in the nuclear light-cone wave functions. (author)

Surface water carbon dioxide in the southwest Indian sector of the Southern Ocean

International Nuclear Information System (INIS)

Metzl, N.; Brunet, C.; Poisson, A.

1991-01-01

Measurements of partial pressure of carbon dioxide (pCO 2 ), total dissolved inorganic carbon (TCO 2 ), total alkalinity (TA) and chlorophyll a (Chl a) have been made in surface water in the southwestern Indian sector of the Southern Ocean (20-85 degE) in the austral summer (INDIVAT V cruise, January-February 1987). Between Antarctica and Africa, pCO 2 distribution was linked to the oceanic frontal zones and Chl a variations. The pCO 2 spatial structure was very close to that explored in summer 1967 in the same region but the pCO 2 differences between the ocean and the atmosphere were smaller in 1987 than 20 years ago. At all latitudes strongly contrasting surface pCO 2 characteristics were found between eastern (around 80 degE) and western (around 25 degE) regions; CO 2 sources were mainly in the west and CO 2 sinks in the east. South of 60 degS, the contrast could be due to biological activity. Between 60 degS and the Antarctic Polar Front, intensification of upwelling might be responsible for the higher pC) 2 values in the west.37 refs.; 4 figs

Simulating the Evolving Behavior of Secondary Slow Slip Fronts

Science.gov (United States)

Peng, Y.; Rubin, A. M.

2017-12-01

High-resolution tremor catalogs of slow slip events reveal secondary slow slip fronts behind the main front that repetitively occupy the same source area during a single episode. These repetitive fronts are most often observed in regions with high tremor density. Their recurrence intervals gradually increase from being too short to be tidally modulated (tens of minutes) to being close to tidal periods (about 12 or 24 hours). This could be explained by a decreasing loading rate from creep in the surrounding regions (with few or no observable tremor events) as the main front passes by. As the recurrence intervals of the fronts increase, eventually they lock in on the tidal periods. We attempt to simulate this numerically using a rate-and-state friction law that transitions from velocity-weakening at low slip speeds to velocity strengthening at high slip speeds. Many small circular patches with a cutoff velocity an order of magnitude higher than that of the background are randomly placed on the fault, in order to simulate the average properties of the high-density tremor zone. Preliminary results show that given reasonable parameters, this model produces similar propagation speeds of the forward-migrating main front inside and outside the high-density tremor zone, consistent with observations. We will explore the behavior of the secondary fronts that arise in this model, in relation to the local density of the small tremor-analog patches, the overall geometry of the tremor zone and the tides.

Explosive development of winter storm Xynthia over the subtropical North Atlantic Ocean

Directory of Open Access Journals (Sweden)

M. L. R. Liberato

2013-09-01

Full Text Available In winter of 2009–2010 south-western Europe was hit by several destructive windstorms. The most important was Xynthia (26–28 February 2010, which caused 64 reported casualties and was classified as the 2nd most expensive natural hazard event for 2010 in terms of economic losses. In this work we assess the synoptic evolution, dynamical characteristics and the main impacts of storm Xynthia, whose genesis, development and path were very uncommon. Wind speed gusts observed at more than 500 stations across Europe are evaluated as well as the wind gust field obtained with a regional climate model simulation for the entire North Atlantic and European area. Storm Xynthia was first identified on 25 February around 30° N, 50° W over the subtropical North Atlantic Ocean. Its genesis occurred on a region characterized by warm and moist air under the influence of a strong upper level wave embedded in the westerlies. Xynthia followed an unusual SW–NE path towards Iberia, France and central Europe. The role of moist air masses on the explosive development of Xynthia is analysed by considering the evaporative sources. A lagrangian model is used to identify the moisture sources, sinks and moisture transport associated with the cyclone during its development phase. The main supply of moisture is located over an elongated region of the subtropical North Atlantic Ocean with anomalously high SST, confirming that the explosive development of storm Xynthia had a significant contribution from the subtropics.

Stability of reaction fronts in random walk simulations

NARCIS (Netherlands)

Nagy, Noemi; Izsak, F.

A model of propagating reaction fronts is given for simple autocatalytic reactions and the stability of the propagating reaction fronts are studied in several numerical experiments. The corresponding random walk simulations - extending of a recent algorithm - make possible the simultaneous treatment

A multitasking, multisinked, multiprocessor data acquisition front end

International Nuclear Information System (INIS)

Fox, R.; Au, R.; Molen, A.V.

1989-01-01

The authors have developed a generalized data acquisition front end system which is based on MC68020 processors running a commercial real time kernel (rhoSOS), and implemented primarily in a high level language (C). This system has been attached to the back end on-line computing system at NSCL via our high performance ETHERNET protocol. Data may be simultaneously sent to any number of back end systems. Fixed fraction sampling along links to back end computing is also supported. A nonprocedural program generator simplifies the development of experiment specific code

Warming of the Indian Ocean Threatens Eastern and Southern Africa, but could be Mitigated by Agricultural Development

Science.gov (United States)

Funk, Chris; Dettinger, Michael D.; Brown, Molly E.; Michaelsen, Joel C.; Verdin, James P.; Barlow, Mathew; Howell, Andrew

2008-01-01

Since 1980, the number of undernourished people in eastern and southern Africa has more than doubled. Rural development stalled and rural poverty expanded during the 1990s. Population growth remains very high and declining per capita agricultural capacity retards progress towards Millennium Development goals. Analyses of in situ station data and satellite observations of precipitation identify another problematic trend. Main growing season rainfall receipts have diminished by approximately 15% in food insecure countries clustered along the western rim of the Indian Ocean. Occurring during the main growing seasons in poor countries dependent on rain fed agriculture, these declines are societally dangerous. Will they persist or intensify? Tracing moisture deficits upstream to an anthropogenically warming Indian Ocean leads us to conclude that further rainfall declines are likely. We present analyses suggesting that warming in the central Indian Ocean disrupts onshore moisture transports, reducing continental rainfall. Thus late 20th century anthropogenic Indian Ocean warming has probably already produced societally dangerous climate change by creating drought and social disruption in some of the world's most fragile food economies. We quantify the potential impacts of the observed precipitation and agricultural capacity trends by modeling millions of undernourished people as a function of rainfall, population, cultivated area, seed and fertilizer use. Persistence of current tendencies may result in a 50% increase in undernourished people. On the other hand, modest increases in per capita agricultural productivity could more than offset the observed precipitation declines. Investing in agricultural development can help mitigate climate change while decreasing rural poverty and vulnerability.

Decadal change of the south Atlantic ocean Angola-Benguela frontal zone since 1980

Science.gov (United States)

Vizy, Edward K.; Cook, Kerry H.; Sun, Xiaoming

2018-01-01

High-resolution simulations with a regional atmospheric model coupled to an intermediate-level mixed layer ocean model along with multiple atmospheric and oceanic reanalyses are analyzed to understand how and why the Angola-Benguela frontal Zone (ABFZ) has changed since 1980. A southward shift of 0.05°-0.55° latitude decade-1 in the annual mean ABFZ position accompanied by an intensification of + 0.05 to + 0.13 K/100-km decade-1 has occurred as ocean mixed layer temperatures have warmed (cooled) equatorward (poleward) of the front over the 1980-2014 period. These changes are captured in a 35-year model integration. The oceanic warming north of the ABFZ is associated with a weakening of vertical entrainment, reduced cooling associated with vertical diffusion, and a deepening of the mixed layer along the Angola coast. These changes coincide with a steady weakening of the onshore atmospheric flow as the zonal pressure gradient between the eastern equatorial Atlantic and the Congo Basin weakens. Oceanic cooling poleward of the ABFZ is primarily due to enhanced advection of cooler water from the south and east, increased cooling by vertical diffusion, and shoaling of the mixed layer depth. In the atmosphere, these changes are related to an intensification and poleward shift of the South Atlantic sub-tropical anticyclone as surface winds, hence the westward mixed layer ocean currents, intensify in the Benguela upwelling region along the Namibian coast. With a few caveats, these findings demonstrate that air/sea interactions play a prominent role in influencing the observed decadal variability of the ABFZ over the southeastern Atlantic since 1980.

Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison.

Science.gov (United States)

van de Schoot, A J A J; Visser, J; van Kesteren, Z; Janssen, T M; Rasch, C R N; Bel, A

2016-02-21

The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D(99%)) and OAR doses (rectum V30Gy; bladder V40Gy). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D(99%), rectum V(30Gy) and bladder V(40Gy) to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D(99%) on average by 0.2 Gy and decreased the median rectum V(30Gy) and median bladder V(40Gy) on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal

Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison

International Nuclear Information System (INIS)

Van de Schoot, A J A J; Visser, J; Van Kesteren, Z; Rasch, C R N; Bel, A; Janssen, T M

2016-01-01

The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D 99% ) and OAR doses (rectum V 30Gy ; bladder V 40Gy ). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D 99% , rectum V 30Gy and bladder V 40Gy to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D 99% on average by 0.2 Gy and decreased the median rectum V 30Gy and median bladder V 40Gy on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal in

Wave fronts of electromagnetic cyclotron harmonic waves

International Nuclear Information System (INIS)

Ohnuma, T.; Watanabe, T.

1982-01-01

In an inhomogeneous high-density magnetized plasma, the spatial properties of the wave fronts and ray trajectories of electromagnetic ordinary and extraordinary cyclotron harmonic waves are investigated. Those waves which are radiated from a local source are found to have wave fronts which are almost parallel to the magnetic field. Also, the reflective properties of the electromagnetic cyclotron harmonic waves are confirmed

Friction forces on phase transition fronts

International Nuclear Information System (INIS)

Mégevand, Ariel

2013-01-01

In cosmological first-order phase transitions, the microscopic interaction of the phase transition fronts with non-equilibrium plasma particles manifests itself macroscopically as friction forces. In general, it is a nontrivial problem to compute these forces, and only two limits have been studied, namely, that of very slow walls and, more recently, ultra-relativistic walls which run away. In this paper we consider ultra-relativistic velocities and show that stationary solutions still exist when the parameters allow the existence of runaway walls. Hence, we discuss the necessary and sufficient conditions for the fronts to actually run away. We also propose a phenomenological model for the friction, which interpolates between the non-relativistic and ultra-relativistic values. Thus, the friction depends on two friction coefficients which can be calculated for specific models. We then study the velocity of phase transition fronts as a function of the friction parameters, the thermodynamic parameters, and the amount of supercooling

Ocean heat content variability and change in an ensemble of ocean reanalyses

Science.gov (United States)

Palmer, M. D.; Roberts, C. D.; Balmaseda, M.; Chang, Y.-S.; Chepurin, G.; Ferry, N.; Fujii, Y.; Good, S. A.; Guinehut, S.; Haines, K.; Hernandez, F.; Köhl, A.; Lee, T.; Martin, M. J.; Masina, S.; Masuda, S.; Peterson, K. A.; Storto, A.; Toyoda, T.; Valdivieso, M.; Vernieres, G.; Wang, O.; Xue, Y.

2017-08-01

Accurate knowledge of the location and magnitude of ocean heat content (OHC) variability and change is essential for understanding the processes that govern decadal variations in surface temperature, quantifying changes in the planetary energy budget, and developing constraints on the transient climate response to external forcings. We present an overview of the temporal and spatial characteristics of OHC variability and change as represented by an ensemble of dynamical and statistical ocean reanalyses (ORAs). Spatial maps of the 0-300 m layer show large regions of the Pacific and Indian Oceans where the interannual variability of the ensemble mean exceeds ensemble spread, indicating that OHC variations are well-constrained by the available observations over the period 1993-2009. At deeper levels, the ORAs are less well-constrained by observations with the largest differences across the ensemble mostly associated with areas of high eddy kinetic energy, such as the Southern Ocean and boundary current regions. Spatial patterns of OHC change for the period 1997-2009 show good agreement in the upper 300 m and are characterized by a strong dipole pattern in the Pacific Ocean. There is less agreement in the patterns of change at deeper levels, potentially linked to differences in the representation of ocean dynamics, such as water mass formation processes. However, the Atlantic and Southern Oceans are regions in which many ORAs show widespread warming below 700 m over the period 1997-2009. Annual time series of global and hemispheric OHC change for 0-700 m show the largest spread for the data sparse Southern Hemisphere and a number of ORAs seem to be subject to large initialization `shock' over the first few years. In agreement with previous studies, a number of ORAs exhibit enhanced ocean heat uptake below 300 and 700 m during the mid-1990s or early 2000s. The ORA ensemble mean (±1 standard deviation) of rolling 5-year trends in full-depth OHC shows a relatively steady

Hard Thermal Loop approximation in the Light Front Quantum Field Theory

International Nuclear Information System (INIS)

Silva, Charles da Rocha; Perez, Silvana

2011-01-01

Full text: In this paper we generalize the Hard Thermal Loop approximation (HTL) for the Thermal Light Front Quantum Field Theory. This technique was developed by Braaten e Pisarski [PRL. 63 (1989) 1129, Nucl. Phys. B337 (1990) 569], for the Thermal Quantum Field Theory at equal time and is particularly useful to solve problems of convergence of the amplitudes within Quantum Chromodynamics, caused by the inherently nonperturbative behavior. The HTL approximation satisfies simple Ward identities, is ultraviolet finite and gauge independent. Here we use the light front generalized coordinates (GLFC) proposed by one of us (V. S. Alves, Ashok Das, e Silvana Perez [PRD. 66, (2002) 125008]) and analyze the one loop amplitudes for the λφ3 theory and the Quantum Electrodynamics in (3+1) dimensions at finite temperature in the HTL approximation. For the scalar theory, we evaluate the two-point function, recovering the usual dispersion relations. We also analyze the rotational invariance of the model. We then consider the Quantum Electrodynamics in (3+1) dimensions and calculate the polarization tensor and the vertex function at finite temperature in the HTL approximation. In future, our interest will be to apply the Generalized Light Front formalism to understand the confinement mechanism which occurs in the Quantum Chromodynamics. There is an expectation that the Light Front Quantum Field Theory formalism is more appropriate to study this problems. (author)

Hard Thermal Loop approximation in the Light Front Quantum Field Theory

Energy Technology Data Exchange (ETDEWEB)

Silva, Charles da Rocha [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil); Universidade Federal do Para (UFPA), Belem, PA (Brazil); Perez, Silvana [Universidade Federal do Para (UFPA), Belem, PA (Brazil)

2011-07-01

Full text: In this paper we generalize the Hard Thermal Loop approximation (HTL) for the Thermal Light Front Quantum Field Theory. This technique was developed by Braaten e Pisarski [PRL. 63 (1989) 1129, Nucl. Phys. B337 (1990) 569], for the Thermal Quantum Field Theory at equal time and is particularly useful to solve problems of convergence of the amplitudes within Quantum Chromodynamics, caused by the inherently nonperturbative behavior. The HTL approximation satisfies simple Ward identities, is ultraviolet finite and gauge independent. Here we use the light front generalized coordinates (GLFC) proposed by one of us (V. S. Alves, Ashok Das, e Silvana Perez [PRD. 66, (2002) 125008]) and analyze the one loop amplitudes for the {lambda}{phi}3 theory and the Quantum Electrodynamics in (3+1) dimensions at finite temperature in the HTL approximation. For the scalar theory, we evaluate the two-point function, recovering the usual dispersion relations. We also analyze the rotational invariance of the model. We then consider the Quantum Electrodynamics in (3+1) dimensions and calculate the polarization tensor and the vertex function at finite temperature in the HTL approximation. In future, our interest will be to apply the Generalized Light Front formalism to understand the confinement mechanism which occurs in the Quantum Chromodynamics. There is an expectation that the Light Front Quantum Field Theory formalism is more appropriate to study this problems. (author)

Measuring Zonal Transport Variability of the Antarctic Circumpolar Current Using GRACE Ocean Bottom Pressure

Science.gov (United States)

Makowski, J.; Chambers, D. P.; Bonin, J. A.

2012-12-01

Previous studies have suggested that ocean bottom pressure (OBP) can be used to measure the transport variability of the Antarctic Circumpolar Current (ACC). Using OBP data from the JPL ECCO model and the Gravity Recovery and Climate Experiment (GRACE), we examine the zonal transport variability of the ACC integrated between the major fronts between 2003-2010. The JPL ECCO data are used to determine average front positions for the time period studies, as well as where transport is mainly zonal. Statistical analysis will be conducted to determine the uncertainty of the GRACE observations using a simulated data set. We will also begin looking at low frequency changes and how coherent transport variability is from region to region of the ACC. Correlations with bottom pressure south of the ACC and the average basin transports will also be calculated to determine the probability of using bottom pressure south of the ACC as a means for describing the ACC dynamics and transport.

Optimal Design of HGV Front Structure for Pedestrian Safety

Science.gov (United States)

Ramli, Faiz Redza; Yamazaki, Koetsu

This paper addresses a pedestrian safety design of front structure of Heavy Goods Vehicle (HGV) by two concepts; firstly by equipping a lower bumper stiffener structure under the front bumper and secondly by putting an airbag in front of the HGV front panel. In this study, HGV-pedestrian collision accident was simulated by the crash analysis solver MADYMO environment, where the HGV model with the speed of 20 km/h was collided with an adult male and with an adult female pedestrian, respectively. The bumper and lower bumper stiffener were varied their positions, while the airbag was adjusted the vent hole size and the position of airbag in front of front panel vertically. The pedestrian injuries that can be sustained during the simulation impact were limited at the critical body parts of head, chest, upper leg; an injury criteria of Head Injury Criterion (HIC), Thorax Cumulative 3ms Acceleration (C3ms) and peak loads of femur, respectively. Because of various parameters and constraints of initial conditions and injury thresholds, a multi-objective optimization design problem considered these main injury criterion is solved in order to achieve the best solution for this study. The results of optimized design parameters for each cases and conditions were obtained and the possibilities of the proposed concept were discussed.

Global Ocean Carbon and Biogeochemistry Coordination

Science.gov (United States)

Telszewski, Maciej; Tanhua, Toste; Palacz, Artur

2016-04-01

The complexity of the marine carbon cycle and its numerous connections to carbon's atmospheric and terrestrial pathways means that a wide range of approaches have to be used in order to establish it's qualitative and quantitative role in the global climate system. Ocean carbon and biogeochemistry research, observations, and modelling are conducted at national, regional, and global levels to quantify the global ocean uptake of atmospheric CO2 and to understand controls of this process, the variability of uptake and vulnerability of carbon fluxes into the ocean. These science activities require support by a sustained, international effort that provides a central communication forum and coordination services to facilitate the compatibility and comparability of results from individual efforts and development of the ocean carbon data products that can be integrated with the terrestrial, atmospheric and human dimensions components of the global carbon cycle. The International Ocean Carbon Coordination Project (IOCCP) was created in 2005 by the IOC of UNESCO and the Scientific Committee on Oceanic Research. IOCCP provides an international, program-independent forum for global coordination of ocean carbon and biogeochemistry observations and integration with global carbon cycle science programs. The IOCCP coordinates an ever-increasing set of observations-related activities in the following domains: underway observations of biogeochemical water properties, ocean interior observations, ship-based time-series observations, large-scale ocean acidification monitoring, inorganic nutrients observations, biogeochemical instruments and autonomous sensors and data and information creation. Our contribution is through the facilitation of the development of globally acceptable strategies, methodologies, practices and standards homogenizing efforts of the research community and scientific advisory groups as well as integrating the ocean biogeochemistry observations with the

Oceans and Human Health: Linking Ocean, Organism, and Human Health for Sustainable Management of Coastal Ecosystems

Science.gov (United States)

Sandifer, P. A.; Trtanj, J.; Collier, T. K.

2012-12-01

Human Health Act of 2004. Major outcomes of the OHH Act of 2004 include: --A national focus on ocean health and its relation to human health and well-being; --Enhanced interagency coordination and cooperation in research, development, and education; --Emphasis on development of a new, interdisciplinary community of practice; --Increased understanding of linkages between marine animal health and human health and the dangers of transmission of zoonotic diseases from the marine environment; --A richer understanding of factors affecting the occurrence and impacts of ocean health threats; --An enhanced ability of the ocean science and public health communities to respond to health-related emergencies; --A strong focus on development of ecological forecasts that are providing early warning of ocean health threats and impacts, thus improving the effectiveness of protection and mitigation actions. Taken together, these outcomes contribute significantly to more sustainable management of coastal resources and communities.

Determination of cut front position in laser cutting

International Nuclear Information System (INIS)

Pereira, M; Thombansen, U

2016-01-01

Laser cutting has a huge importance to manufacturing industry. Laser cutting machines operate with fixed technological parameters and this does not guarantee the best productivity. The adjustment of the cutting parameters during operation can improve the machine performance. Based on a coaxial measuring device it is possible to identify the cut front position during the cutting process. This paper describes the data analysis approach used to determine the cut front position for different feed rates. The cut front position was determined with good resolution, but improvements are needed to make the whole process more stable. (paper)

AdS/QCD and Applications of Light-Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Cao, Fu-Guang; /Massey U.; de Teramond, Guy F.; /Costa Rica U.

2012-02-16

Light-Front Holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space and frame-independent light-front wavefunctions of hadrons in 3 + 1 physical space-time, thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD, a useful framework which describes the correspondence between theories in a modified AdS5 background and confining field theories in physical space-time. To a first semiclassical approximation, where quantum loops and quark masses are not included, this approach leads to a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role. We give an overview of the light-front holographic approach to strongly coupled QCD. In particular, we study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The results for the TFFs for the {eta} and {eta}' mesons are also presented. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.

International Ocean Symposium (IOS) 1996; Kokusai kaiyo symposium 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-02-18

This is a proceedings of the International Ocean Symposium 1996. On the first day of the symposium, the following were given with a theme `The Ocean, Can She Save Us`: Underwater research and future of mankind as a commemorative speech; The ocean, can she save us -- trying to discover the true figure of the ocean as a keynote speech. Panel discussion was held on The global environment and the infinite potential of the ocean. On the second day, an approach was made mostly from a cultural aspect with a theme `The Ocean and the Japanese.` The following were given: Human links between east and west as a commemorative speech; The ocean and Japanese culture as a keynote speech; Civilization spanning across oceans as a panel discussion. The Japanese have been developing their individual technologies in shipbuilding, shipping, and ocean development, have been raised by Mother Ocean, and have lived together. Ocean has been supplying humans food, water, oxygen, marine routes, and even dream and hope. The environmental pollution is the result of the human greediness. It is fear and friendship between humans and ocean that can save humans and ocean.

Networking Multiple Autonomous Air and Ocean Vehicles for Oceanographic Research and Monitoring

Science.gov (United States)

McGillivary, P. A.; Borges de Sousa, J.; Rajan, K.

2013-12-01

Autonomous underwater and surface vessels (AUVs and ASVs) are coming into wider use as components of oceanographic research, including ocean observing systems. Unmanned airborne vehicles (UAVs) are now available at modest cost, allowing multiple UAVs to be deployed with multiple AUVs and ASVs. For optimal use good communication and coordination among vehicles is essential. We report on the use of multiple AUVs networked in communication with multiple UAVs. The UAVs are augmented by inferential reasoning software developed at MBARI that allows UAVs to recognize oceanographic fronts and change their navigation and control. This in turn allows UAVs to automatically to map frontal features, as well as to direct AUVs and ASVs to proceed to such features and conduct sampling via onboard sensors to provide validation for airborne mapping. ASVs can also act as data nodes for communication between UAVs and AUVs, as well as collecting data from onboard sensors, while AUVs can sample the water column vertically. This allows more accurate estimation of phytoplankton biomass and productivity, and can be used in conjunction with UAV sampling to determine air-sea flux of gases (e.g. CO2, CH4, DMS) affecting carbon budgets and atmospheric composition. In particular we describe tests in July 2013 conducted off Sesimbra, Portugal in conjunction with the Portuguese Navy by the University of Porto and MBARI with the goal of tracking large fish in the upper water column with coordinated air/surface/underwater measurements. A thermal gradient was observed in the infrared by a low flying UAV, which was used to dispatch an AUV to obtain ground truth to demonstrate the event-response capabilities using such autonomous platforms. Additional field studies in the future will facilitate integration of multiple unmanned systems into research vessel operations. The strength of hardware and software tools described in this study is to permit fundamental oceanographic measurements of both ocean

Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

Science.gov (United States)

Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

2017-01-01

In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

Deep sub-micron FD-SOI for front-end application

International Nuclear Information System (INIS)

Ikeda, H.; Arai, Y.; Hara, K.; Hayakawa, H.; Hirose, K.; Ikegami, Y.; Ishino, H.; Kasaba, Y.; Kawasaki, T.; Kohriki, T.; Martin, E.; Miyake, H.; Mochizuki, A.; Tajima, H.; Tajima, O.; Takahashi, T.; Takashima, T.; Terada, S.; Tomita, H.; Tsuboyama, T.

2007-01-01

In order to confirm benefits of a deep sub-micron FD-SOI and to identify possible issues concerning front-end circuits with the FD-SOI, we have submitted a small design to Oki Electric Industry Co., Ltd. via the multi-chip project service of VDEC, the University of Tokyo. The initial test results and future plans for development are presented

Robust Spectrum Sensing Demonstration Using a Low-Cost Front-End Receiver

Directory of Open Access Journals (Sweden)

Daniele Borio

2015-01-01

Full Text Available Spectrum Sensing (SS is an important function in Cognitive Radio (CR to detect primary users. The design of SS algorithms is one of the most challenging tasks in CR and requires innovative hardware and software solutions to enhance detection probability and minimize low false alarm probability. Although several SS algorithms have been developed in the specialized literature, limited work has been done to practically demonstrate the feasibility of this function on platforms with significant computational and hardware constraints. In this paper, SS is demonstrated using a low cost TV tuner as agile front-end for sensing a large portion of the Ultra-High Frequency (UHF spectrum. The problems encountered and the limitations imposed by the front-end are analysed along with the solutions adopted. Finally, the spectrum sensor developed is implemented on an Android device and SS implementation is demonstrated using a smartphone.

5-D interpolation with wave-front attributes

Science.gov (United States)

Xie, Yujiang; Gajewski, Dirk

2017-11-01

Most 5-D interpolation and regularization techniques reconstruct the missing data in the frequency domain by using mathematical transforms. An alternative type of interpolation methods uses wave-front attributes, that is, quantities with a specific physical meaning like the angle of emergence and wave-front curvatures. In these attributes structural information of subsurface features like dip and strike of a reflector are included. These wave-front attributes work on 5-D data space (e.g. common-midpoint coordinates in x and y, offset, azimuth and time), leading to a 5-D interpolation technique. Since the process is based on stacking next to the interpolation a pre-stack data enhancement is achieved, improving the signal-to-noise ratio (S/N) of interpolated and recorded traces. The wave-front attributes are determined in a data-driven fashion, for example, with the Common Reflection Surface (CRS method). As one of the wave-front-attribute-based interpolation techniques, the 3-D partial CRS method was proposed to enhance the quality of 3-D pre-stack data with low S/N. In the past work on 3-D partial stacks, two potential problems were still unsolved. For high-quality wave-front attributes, we suggest a global optimization strategy instead of the so far used pragmatic search approach. In previous works, the interpolation of 3-D data was performed along a specific azimuth which is acceptable for narrow azimuth acquisition but does not exploit the potential of wide-, rich- or full-azimuth acquisitions. The conventional 3-D partial CRS method is improved in this work and we call it as a wave-front-attribute-based 5-D interpolation (5-D WABI) as the two problems mentioned above are addressed. Data examples demonstrate the improved performance by the 5-D WABI method when compared with the conventional 3-D partial CRS approach. A comparison of the rank-reduction-based 5-D seismic interpolation technique with the proposed 5-D WABI method is given. The comparison reveals that

Sismonaute. Un système pour la détection et l'interprétation des fronts d'onde en simulation sismique Sismonaute. A System for Detecting and Interpreting Wave Fronts in Seismic Simulations

Directory of Open Access Journals (Sweden)

Junker U.

2006-11-01

Full Text Available Nous développons un système, dénommé SISMONAUTE, d'aide aux géophysiciens pour l'étude de la propagation des ondes dans un modèle postulé de sous-sol. Le système suit les fronts d'onde dans une série d'instantanés 2D produits par un simulateur numérique. De plus, il rétablit l'historique de l'onde, c'est-à-dire la séquence des réflexions, transmissions et diffractions qui représente des transformations qualitatives de l'onde. Cet historique est essentiel pour la comparaison des sismogrammes simulés et observés. Nous utilisons pour interpréter les données de simulation un système dirigé par les connaissances qui applique le raisonnement causal pour prédire, à chaque stade, de nouveaux fronts d'onde. Ces fronts prédits permettent une détection guidée des fronts d'onde sur les instantanés. We are developing a system, called SISMONAUTE, that supports a geophysicist in studying the propagation of waves in a postulated model of the subsoil. The system tracks the wave fronts in a sequence of 2D-snapshots produced by a numerical simulator. Furthermore, it recovers the history of a wave, i. e. the sequence of reflections, transmissions, and diffractions which represents qualitative changes of the wave. This history is essential for comparing simulated and observed seismograms. We use a knowledge-driven approach to interpret the simulated data. Using causal reasoning, the system predicts new wave fronts in each step. These predicted fronts enable a guided detection of wave fronts in the snapshots.

Null geodesics and wave front singularities in the Gödel space-time

Science.gov (United States)

Kling, Thomas P.; Roebuck, Kevin; Grotzke, Eric

2018-01-01

We explore wave fronts of null geodesics in the Gödel metric emitted from point sources both at, and away from, the origin. For constant time wave fronts emitted by sources away from the origin, we find cusp ridges as well as blue sky metamorphoses where spatially disconnected portions of the wave front appear, connect to the main wave front, and then later break free and vanish. These blue sky metamorphoses in the constant time wave fronts highlight the non-causal features of the Gödel metric. We introduce a concept of physical distance along the null geodesics, and show that for wave fronts of constant physical distance, the reorganization of the points making up the wave front leads to the removal of cusp ridges.

Concepts for a Muon Accelerator Front-End

Energy Technology Data Exchange (ETDEWEB)

Stratakis, Diktys [Fermilab; Berg, Scott [Brookhaven; Neuffer, David [Fermilab

2017-03-16

We present a muon capture front-end scheme for muon based applications. In this Front-End design, a proton bunch strikes a target and creates secondary pions that drift into a capture channel, decaying into muons. A series of rf cavities forms the resulting muon beams into a series of bunches of differerent energies, aligns the bunches to equal central energies, and initiates ionization cooling. We also discuss the design of a chicane system for the removal of unwanted secondary particles from the muon capture region and thus reduce activation of the machine. With the aid of numerical simulations we evaluate the performance of this Front-End scheme as well as study its sensitivity against key parameters such as the type of target, the number of rf cavities and the gas pressure of the channel.

Discretionary Power on the Front-line

DEFF Research Database (Denmark)

Sanden, Guro Refsum; Lønsmann, Dorte

This article investigates the communication practices used by front-line employees to cross language boundaries in the context of English language policies implemented by the management of three multinational corporations (MNCs) headquartered in Scandinavia. Based on an analysis of interview...... and document data, our findings show that employees face a number of different language boundaries in their everyday work, and that ad hoc and informal solutions in many cases are vital for successful cross-language communication. We introduce the concept of ‘discretionary power’ to explain how and why front...

Discretionary power on the front-line

DEFF Research Database (Denmark)

Sanden, Guro Refsum; Lønsmann, Dorte

2018-01-01

This article investigates the communication practices used by front-line employees to cross language boundaries in the context of English language policies implemented by the management of three multinational corporations headquartered in Scandinavia. Based on an analysis of interview and document...... data, our findings show that employees face a number of different language boundaries in their everyday work, and that ad hoc and informal solutions in many cases are vital for successful cross-language communication. We introduce the concept of discretionary power to explain how and why front...

Discretionary Power on the Front Line

DEFF Research Database (Denmark)

Sanden, Guro Refsum; Lønsmann, Dorte

2018-01-01

This paper investigates the communication practices used by front-line employees to cross language boundaries in the context of English language policies implemented by the management of three multinational corporations (MNCs) headquartered in Scandinavia. Based on an analysis of interview...... and document data, our findings show that employees face a number of different language boundaries in their everyday work, and that ad hoc and informal solutions in many cases are vital for successful cross-language communication. We introduce the concept of 'discretionary power' to explain how and why front...

Gluon cascades and amplitudes in light-front perturbation theory

International Nuclear Information System (INIS)

Cruz-Santiago, C.A.; Staśto, A.M.

2013-01-01

We construct the gluon wave functions, fragmentation functions and scattering amplitudes within the light-front perturbation theory. Recursion relations on the light-front are constructed for the wave functions and fragmentation functions, which in the latter case are the light-front analogs of the Berends–Giele recursion relations. Using general relations between wave functions and scattering amplitudes it is demonstrated how to obtain the maximally-helicity violating amplitudes, and explicit verification of the results is based on simple examples.

Digital front-end module (DFEM) series; Digital front end module (DFEM) series

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The digital front-end module (DFEM) is a module in which the processes ranging from the reception of digitally modulated radiofrequencies to the output of digital IF (Intermediate Frequency) signals or data streams are integrated. Beginning with a module for the MCNS (Multimedia Cable Network System) cable modem which was the first module in this business field approved by the Cable Labs, U.S., Toshiba has developed a series of DFEMs for various digital media for satellites, ground waves, and CATV (Cable Television) systems. The series is characterized by (1) the serialization of DFEMs compatible with various digital modulation techniques such as 8 PSK (Phase Shift Keying), OFDM (Orthogonal Frequency Division Multiplexing), and 256 QAM (Quadrature Amplitude Modulation), (2) easy connection with digital circuits thanks to the high shielding effect, and (3) the achievement of smaller size, higher performance, and lower power consumption. (translated by NEDO)

Marine Biology Activities. Ocean Related Curriculum Activities.

Science.gov (United States)

Pauls, John

The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

A Full Front End Chain for Drift Chambers

Energy Technology Data Exchange (ETDEWEB)

Chiarello, G. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Corvaglia, A.; Grancagnolo, F. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Panareo, M. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Pepino, A., E-mail: aurora.pepino@le.infn.it [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Primiceri, P. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Tassielli, G. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Fermilab, Batavia, Illinois (United States); Università Marconi, Roma (Italy)

2014-03-01

We developed a high performance full chain for drift chamber signals processing. The Front End electronics is a multistage amplifier board based on high performance commercial devices. In addition a fast readout algorithm for Cluster Counting and Timing purposes has been implemented on a Xilinx-Virtex 4 core FPGA. The algorithm analyzes and stores data coming from a Helium based drift tube and represents the outcome of balancing between efficiency and high speed performance.

"Front" hotshet izvinitsja / Aleksandr Ikonnikov

Index Scriptorium Estoniae

Ikonnikov, Aleksandr

2003-01-01

Põhiliselt vene rahvusest noori ühendava liikumise "Front" esindajad kavatsevad kohtuda USA suursaadikuga Eestis ja vabandada kevadel suursaatkonna ees vägivallatsemisega lõppenud meeleavalduse pärast

Variability, interaction and change in the atmosphere-ocean-ecology system of the Western Indian Ocean.

Science.gov (United States)

Spencer, T; Laughton, A S; Flemming, N C

2005-01-15

Traditional ideas of intraseasonal and interannual climatic variability in the Western Indian Ocean, dominated by the mean cycle of seasonally reversing monsoon winds, are being replaced by a more complex picture, comprising air-sea interactions and feedbacks; atmosphere-ocean dynamics operating over intrannual to interdecadal time-scales; and climatological and oceanographic boundary condition changes at centennial to millennial time-scales. These forcings, which are mediated by the orography of East Africa and the Asian continent and by seafloor topography (most notably in this area by the banks and shoals of the Mascarene Plateau which interrupts the westward-flowing South Equatorial Current), determine fluxes of water, nutrients and biogeochemical constituents, the essential controls on ocean and shallow-sea productivity and ecosystem health. Better prediction of climatic variability for rain-fed agriculture, and the development of sustainable marine resource use, is of critical importance to the developing countries of this region but requires further basic information gathering and coordinated ocean observation systems.

Ocean Wave Simulation Based on Wind Field.

Directory of Open Access Journals (Sweden)

Zhongyi Li

Full Text Available Ocean wave simulation has a wide range of applications in movies, video games and training systems. Wind force is the main energy resource for generating ocean waves, which are the result of the interaction between wind and the ocean surface. While numerous methods to handle simulating oceans and other fluid phenomena have undergone rapid development during the past years in the field of computer graphic, few of them consider to construct ocean surface height field from the perspective of wind force driving ocean waves. We introduce wind force to the construction of the ocean surface height field through applying wind field data and wind-driven wave particles. Continual and realistic ocean waves result from the overlap of wind-driven wave particles, and a strategy was proposed to control these discrete wave particles and simulate an endless ocean surface. The results showed that the new method is capable of obtaining a realistic ocean scene under the influence of wind fields at real time rates.

The Role of Mid-Atlantic Ocean Data Portal in Supporting Ocean Planning

Directory of Open Access Journals (Sweden)

Richard G. Lathrop

2017-08-01

Full Text Available The Mid-Atlantic Regional Council on the Ocean (MARCO was established in 2009 to enhance the vitality of the region's ocean ecosystem and economy. One of MARCO's first action items was the development of the Mid-Atlantic Ocean Data Portal to serve as an on-line platform to engage stakeholders across the region with the objective of improving their understanding of how ocean resources and places are being used, managed, and conserved. A key component is the Marine Planner, an interactive map-based visualization and decision support tool. These types of on-line tools are becoming increasingly popular means of putting essential data and state-of-the-art visualization technology into the hands of the agencies, industry, community leaders, and stakeholders engaged in ocean planning. However, to be effective, the underlying geospatial data has to be seen as objective, comprehensive, up-to-date and regionally consistent. To meet this challenge, the portal utilizes a distributed network of web map services from credible and authoritative sources. Website analytics and feedback received during the review and comment period of the 2016 release of the Mid-Atlantic Ocean Action Plan confirm that the Data Portal is viewed as integral to this ocean planning process by the MidAtlantic Regional Planning Body and key stakeholders. While not all stakeholders may agree with specific planning decisions, there is broad based agreement on the need for better data and making access to that data widely available.

The ocean planet.

Science.gov (United States)

Hinrichsen, D

1998-01-01

The Blue Planet is 70% water, and all but 3% of it is salt water. Life on earth first evolved in the primordial soup of ancient seas, and though today's seas provide 99% of all living space on the planet, little is known about the world's oceans. However, the fact that the greatest threats to the integrity of our oceans come from land-based activities is becoming clear. Humankind is in the process of annihilating the coastal and ocean ecosystems and the wealth of biodiversity they harbor. Mounting population and development pressures have taken a grim toll on coastal and ocean resources. The trend arising from such growth is the chronic overexploitation of marine resources, whereby rapidly expanding coastal populations and the growth of cities have contributed to a rising tide of pollution in nearly all of the world's seas. This crisis is made worse by government inaction and a frustrating inability to enforce existing coastal and ocean management regulations. Such inability is mainly because concerned areas contain so many different types of regulations and involve so many levels of government, that rational planning and coordination of efforts are rendered impossible. Concerted efforts are needed by national governments and the international community to start preserving the ultimate source of all life on earth.

Co-ordination Action on Ocean Energy (CA-OE)

DEFF Research Database (Denmark)

Tedd, James; Frigaard, Peter

In October 2004, the Co-ordination Action on Ocean Energy (CA-OE) was launched, co-financed by the European Commission, under the Renewable Energy Technologies priority within the 6th Framework programme, contract number 502701, chaired by Kim Nielsen, Rambøll, Denmark. The project involves 41...... partners. In general the public is not aware of the development of ocean energy and its exploitation. There is a need to make a united effort from the developers and research community to present the various principles and results in a coordinated manner with public appeal. The main objectives of the Co......-ordination Action on Ocean Energy are: To develop a common knowledge base necessary for coherent research and development policiesTo bring a co-ordinated approach within key areas of ocean energy research and development.To provide a forum for the longer term marketing of promising research developments...

Dynamic transition in the structure of an energetic crystal during chemical reactions at shock front prior to detonation.

Science.gov (United States)

Nomura, Ken-Ichi; Kalia, Rajiv K; Nakano, Aiichiro; Vashishta, Priya; van Duin, Adri C T; Goddard, William A

2007-10-05

Mechanical stimuli in energetic materials initiate chemical reactions at shock fronts prior to detonation. Shock sensitivity measurements provide widely varying results, and quantum-mechanical calculations are unable to handle systems large enough to describe shock structure. Recent developments in reactive force-field molecular dynamics (ReaxFF-MD) combined with advances in parallel computing have paved the way to accurately simulate reaction pathways along with the structure of shock fronts. Our multimillion-atom ReaxFF-MD simulations of l,3,5-trinitro-l,3,5-triazine (RDX) reveal that detonation is preceded by a transition from a diffuse shock front with well-ordered molecular dipoles behind it to a disordered dipole distribution behind a sharp front.

Mapping the ocean current strength and persistence in the Agulhas to inform marine energy development

CSIR Research Space (South Africa)

Meyer, I

2017-04-01

Full Text Available sensing - Acoustic Doppler Current Profiler - Natal pulses U N C O R R EC TE D PR O O F 1 Mapping the Ocean Current Strength 2 and Persistence in the Agulhas to Inform 3 Marine Energy Development 4 I. Meyer, L. Braby, M. Krug and B. Backeberg 5... International Publishing AG 2017 Z. Yang and A. Copping (eds.), Marine Renewable Energy, DOI 10.1007/978-3-319-53536-4_8 1 A u th o r P ro o f U N C O R R EC TE D PR O O F 16 Current. Western boundary ocean currents have become an area of focus (Duerr and 17...

The role of Southern Ocean mixing and upwelling in glacial-interglacial atmospheric CO2 change

International Nuclear Information System (INIS)

Watson, Andrew J.; Naveira Garabato, Alberto C.

2006-01-01

Decreased ventilation of the Southern Ocean in glacial time is implicated in most explanations of lower glacial atmospheric CO 2 . Today, the deep (>2000 m) ocean south of the Polar Front is rapidly ventilated from below, with the interaction of deep currents with topography driving high mixing rates well up into the water column. We show from a buoyancy budget that mixing rates are high in all the deep waters of the Southern Ocean. Between the surface and 2000 m depth, water is upwelled by a residual meridional overturning that is directly linked to buoyancy fluxes through the ocean surface. Combined with the rapid deep mixing, this upwelling serves to return deep water to the surface on a short time scale. We propose two new mechanisms by which, in glacial time, the deep Southern Ocean may have been more isolated from the surface. Firstly, the deep ocean appears to have been more stratified because of denser bottom water resulting from intense sea ice formation near Antarctica. The greater stratification would have slowed the deep mixing. Secondly, subzero atmospheric temperatures may have meant that the present-day buoyancy flux from the atmosphere to the ocean surface was reduced or reversed. This in turn would have reduced or eliminated the upwelling (contrary to a common assumption, upwelling is not solely a function of the wind stress but is coupled to the air/sea buoyancy flux too). The observed very close link between Antarctic temperatures and atmospheric CO 2 could then be explained as a natural consequence of the connection between the air/sea buoyancy flux and upwelling in the Southern Ocean, if slower ventilation of the Southern Ocean led to lower atmospheric CO 2 . Here we use a box model, similar to those of previous authors, to show that weaker mixing and reduced upwelling in the Southern Ocean can explain the low glacial atmospheric CO 2 in such a formulation

Ranking of microRNA target prediction scores by Pareto front analysis.

Science.gov (United States)

Sahoo, Sudhakar; Albrecht, Andreas A

2010-12-01

Over the past ten years, a variety of microRNA target prediction methods has been developed, and many of the methods are constantly improved and adapted to recent insights into miRNA-mRNA interactions. In a typical scenario, different methods return different rankings of putative targets, even if the ranking is reduced to selected mRNAs that are related to a specific disease or cell type. For the experimental validation it is then difficult to decide in which order to process the predicted miRNA-mRNA bindings, since each validation is a laborious task and therefore only a limited number of mRNAs can be analysed. We propose a new ranking scheme that combines ranked predictions from several methods and - unlike standard thresholding methods - utilises the concept of Pareto fronts as defined in multi-objective optimisation. In the present study, we attempt a proof of concept by applying the new ranking scheme to hsa-miR-21, hsa-miR-125b, and hsa-miR-373 and prediction scores supplied by PITA and RNAhybrid. The scores are interpreted as a two-objective optimisation problem, and the elements of the Pareto front are ranked by the STarMir score with a subsequent re-calculation of the Pareto front after removal of the top-ranked mRNA from the basic set of prediction scores. The method is evaluated on validated targets of the three miRNA, and the ranking is compared to scores from DIANA-microT and TargetScan. We observed that the new ranking method performs well and consistent, and the first validated targets are elements of Pareto fronts at a relatively early stage of the recurrent procedure, which encourages further research towards a higher-dimensional analysis of Pareto fronts. Copyright © 2010 Elsevier Ltd. All rights reserved.

Beyond electricity: The potential of ocean thermal energy and ocean technology ecoparks in small tropical islands

International Nuclear Information System (INIS)

Osorio, Andrés F.; Arias-Gaviria, Jessica; Devis-Morales, Andrea; Acevedo, Diego; Velasquez, Héctor Iván; Arango-Aramburo, Santiago

2016-01-01

Small islands face difficult challenges to guarantee energy, freshwater and food supply, and sustainable development. The urge to meet their needs, together with the mitigation and adaptation plans to address climate change, have led them to develop renewable energy systems, with a special interest in Ocean Thermal Energy Conversion (OTEC) in tropical islands. Deep Ocean Water (DOW) is a resource that can provide electricity (through OTEC in combination with warm surface water), low temperatures for refrigeration, and nutrients for food production. In this paper we propose an Ocean Technology Ecopark (OTEP) as an integral solution for small islands that consists of an OTEC plant, other alternative uses of DOW, and a Research and Development (R&D) center. We present an application of OTEP to San Andres, a Colombian island that meets all the necessary conditions for the implementation of OTEC technology, water desalinization, and a business model for DOW. We present the main entrance barriers and a four-stage roadmap for the consolidation and sustainability of the OTEP. - Highlights: • Small islands face problems such as development, energy, freshwater and food supply. • Tropical islands with access to deep ocean water can use OTEC all year round. • An Ocean Ecopark is proposed as an integral solution for San Andrés Island, Colombia. • The Ecopark consists of OTEC, desalinization, SWAC, greenhouses, and R&D activities. • This article discusses entrance barriers and presents a four-stage roadmap

Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle