WorldWideScience

Sample records for surface currents predicted

  1. Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

    Science.gov (United States)

    Messié, Monique; Chavez, Francisco P.

    2017-09-01

    A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

  2. Predictive Surface Complexation Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, Dimitri A. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Earth and Planetary Sciences

    2016-11-29

    Surface complexation plays an important role in the equilibria and kinetics of processes controlling the compositions of soilwaters and groundwaters, the fate of contaminants in groundwaters, and the subsurface storage of CO2 and nuclear waste. Over the last several decades, many dozens of individual experimental studies have addressed aspects of surface complexation that have contributed to an increased understanding of its role in natural systems. However, there has been no previous attempt to develop a model of surface complexation that can be used to link all the experimental studies in order to place them on a predictive basis. Overall, my research has successfully integrated the results of the work of many experimentalists published over several decades. For the first time in studies of the geochemistry of the mineral-water interface, a practical predictive capability for modeling has become available. The predictive correlations developed in my research now enable extrapolations of experimental studies to provide estimates of surface chemistry for systems not yet studied experimentally and for natural and anthropogenically perturbed systems.

  3. The Influence of Wind on HF Radar Surface Current Forecasts

    National Research Council Canada - National Science Library

    De Almeida, Francisco M

    2008-01-01

    The ability to predict surface currents can have a beneficial impact in several activities, such as Search and Rescue and Oil Spill Response, as well as others more purely scientific, operational or economic...

  4. Surface current density K: an introduction

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1991-01-01

    The author discusses the vector surface of current density K used in electrical insulation studies. K is related to the vector tangential electric field Kt at the surface of a body by the vector equation K=ΓE t where Γ represents the surface conductivity. The author derives a surface continuity...

  5. Electric fields associated with transient surface currents

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1992-01-01

    The boundary condition to be fulfilled by the potential functions associated with a transient surface current is derived and expressed in terms of generalized orthogonal coordinates. From the analysis, it can be deduced that the use of the method of separation of variables is restricted to three ...

  6. Predicting the importance of current papers.

    Energy Technology Data Exchange (ETDEWEB)

    Klavans, Richard (SciTech Strategies, Inc., Berwyn, PA); Boyack, Kevin W.

    2005-01-01

    This article examines how well one can predict the importance of a current paper (a paper that is recently published in the literature). We look at three factors--journal importance, reference importance and author reputation. Citation-based measures of importance are used for all variables. We find that journal importance is the best predictor (explaining 22.3% out of a potential 29.1% of the variance in the data), and that this correlation value varies significantly by discipline. Journal importance is a better predictor of citation in Computer Science than in any other discipline. While the finding supports the present policy of using journal impact statistics as a surrogate for the importance of current papers, it calls into question the present policy of equally weighting current documents in text-based analyses. We suggest that future researchers take into account the expected importance of a document when attempting to describe the cognitive structure of a field.

  7. Eddy Current Probe for Surface and Sub-Surface Inspection

    Science.gov (United States)

    Wincheski, Russell A. (Inventor); Simpson, John W. (Inventor)

    2014-01-01

    An eddy current probe includes an excitation coil for coupling to a low-frequency alternating current (AC) source. A magneto-resistive sensor is centrally disposed within and at one end of the excitation coil to thereby define a sensing end of the probe. A tubular flux-focusing lens is disposed between the excitation coil and the magneto-resistive sensor. An excitation wire is spaced apart from the magneto-resistive sensor in a plane that is perpendicular to the sensor's axis of sensitivity and such that, when the sensing end of the eddy current probe is positioned adjacent to the surface of a structure, the excitation wire is disposed between the magneto-resistive sensor and the surface of the structure. The excitation wire is coupled to a high-frequency AC source. The excitation coil and flux-focusing lens can be omitted when only surface inspection is required.

  8. Helicopter Rotor Noise Prediction: Background, Current Status, and Future Direction

    Science.gov (United States)

    Brentner, Kenneth S.

    1997-01-01

    Helicopter noise prediction is increasingly important. The purpose of this viewgraph presentation is to: 1) Put into perspective the recent progress; 2) Outline current prediction capabilities; 3) Forecast direction of future prediction research; 4) Identify rotorcraft noise prediction needs. The presentation includes an historical perspective, a description of governing equations, and the current status of source noise prediction.

  9. Predictability of the California Current System

    Science.gov (United States)

    Miller, Arthur J.; Chereskin, T.; Cornuelle, B. D.; Niiler, P. P.; Moisan, J. R.; Lindstrom, Eric (Technical Monitor)

    2001-01-01

    The physical and biological oceanography of the Southern California Bight (SCB), a highly productive subregion of the California Current System (CCS) that extends from Point Conception, California, south to Ensenada, Mexico, continues to be extensively studied. For example, the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has sampled this region for over 50 years, providing an unparalleled time series of physical and biological data. However, our understanding of what physical processes control the large-scale and mesoscale variations in these properties is incomplete. In particular, the non-synoptic and relatively coarse spatial sampling (70km) of the hydrographic grid does not completely resolve the mesoscale eddy field (Figure 1a). Moreover, these unresolved physical variations exert a dominant influence on the evolution of the ecosystem. In recent years, additional datasets that partially sample the SCB have become available. Acoustic Doppler Current Profiler (ADCP) measurements, which now sample upper-ocean velocity between stations, and sea level observations along TOPEX tracks give a more complete picture of the mesoscale variability. However, both TOPEX and ADCP are well-sampled only along the cruise or orbit tracks and coarsely sampled in time and between tracks. Surface Lagrangian drifters also sample the region, although irregularly in time and space. SeaWiFS provides estimates of upper-ocean chlorophyll-a (chl-alpha), usually giving nearly complete coverage for week-long intervals, depending on cloud coverage. Historical ocean color data from the Coastal Zone Color Scanner (CZCS) has been used extensively to determine phytoplankton patterns and variability, characterize the primary production across the SCB coastal fronts, and describe the seasonal and interannual variability in pigment concentrations. As in CalCOFI, these studies described much of the observed structures and their variability over relatively large space and

  10. Generalised empirical method for predicting surface subsidence

    International Nuclear Information System (INIS)

    Zhang, M.; Bhattacharyya, A.K.

    1994-01-01

    Based on a simplified strata parameter, i.e. the ratio of total thickness of the strong rock beds in an overburden to the overall thickness of the overburden, a Generalised Empirical Method (GEM) is described for predicting the maximum subsidence and the shape of a complete transverse subsidence profile due to a single completely extracted longwall panel. In the method, a nomogram for predicting the maximum surface subsidence is first developed from the data collected from subsidence measurements worldwide. Then, a method is developed for predicting the shapes of complete transfer subsidence profiles for a horizontal seam and ground surface and is verified by case studies. 13 refs., 9 figs., 2 tabs

  11. Measuring surface current velocities in the Agulhas region with ASAR

    CSIR Research Space (South Africa)

    Rouault, MJ

    2010-01-01

    Full Text Available Surface current information collected over the Agulhas Current region and derived from the Doppler centroid anomalies of the Advanced Synthetic Aperture Radar (ASAR) are examined. The sources of errors and potential use of the radar surface...

  12. Surface science principles and current applications

    CERN Document Server

    Taglauer, E; Wandelt, K

    1996-01-01

    Modern technologies increasingly rely on low-dimensional physics at interfaces and in thin-films and nano-structures. Surface science holds a key position in providing the experimental methods and theoretical models for a basic understanding of these effects. This book includes case studies and status reports about research topics such as: surface structure determination by tensor-LEED and surface X-ray diffraction; the preparation and detection of low-dimensional electronic surface states; quantitative surface compositional analysis; the dynamics of adsorption and reaction of adsorbates, e.g. kinetic oscillations; the characterization and control of thin-film and multilayer growth including the influence of surfactants; a critical assessment of the surface physics approach to heterogeneous catalysis.

  13. Current trends of surface science and catalysis

    CERN Document Server

    Park, Jeong Young

    2014-01-01

    Including detail on applying surface science in renewable energy conversion, this book covers the latest results on model catalysts including single crystals, bridging "materials and pressure gaps", and hot electron flows in heterogeneous catalysis.

  14. New horizons in predictive toxicology: current status and application

    National Research Council Canada - National Science Library

    Wilson, A. G. E

    2012-01-01

    "In this comprehensive discussion of predictive toxicology and its applications, leading experts express their views on the technologies currently available and the potential for future developments...

  15. Prediction of surface distress using neural networks

    Science.gov (United States)

    Hamdi, Hadiwardoyo, Sigit P.; Correia, A. Gomes; Pereira, Paulo; Cortez, Paulo

    2017-06-01

    Road infrastructures contribute to a healthy economy throughout a sustainable distribution of goods and services. A road network requires appropriately programmed maintenance treatments in order to keep roads assets in good condition, providing maximum safety for road users under a cost-effective approach. Surface Distress is the key element to identify road condition and may be generated by many different factors. In this paper, a new approach is aimed to predict Surface Distress Index (SDI) values following a data-driven approach. Later this model will be accordingly applied by using data obtained from the Integrated Road Management System (IRMS) database. Artificial Neural Networks (ANNs) are used to predict SDI index using input variables related to the surface of distress, i.e., crack area and width, pothole, rutting, patching and depression. The achieved results show that ANN is able to predict SDI with high correlation factor (R2 = 0.996%). Moreover, a sensitivity analysis was applied to the ANN model, revealing the influence of the most relevant input parameters for SDI prediction, namely rutting (59.8%), crack width (29.9%) and crack area (5.0%), patching (3.0%), pothole (1.7%) and depression (0.3%).

  16. Gold nanoparticles with patterned surface monolayers for nanomedicine: current perspectives.

    Science.gov (United States)

    Pengo, Paolo; Şologan, Maria; Pasquato, Lucia; Guida, Filomena; Pacor, Sabrina; Tossi, Alessandro; Stellacci, Francesco; Marson, Domenico; Boccardo, Silvia; Pricl, Sabrina; Posocco, Paola

    2017-12-01

    Molecular self-assembly is a topic attracting intense scientific interest. Various strategies have been developed for construction of molecular aggregates with rationally designed properties, geometries, and dimensions that promise to provide solutions to both theoretical and practical problems in areas such as drug delivery, medical diagnostics, and biosensors, to name but a few. In this respect, gold nanoparticles covered with self-assembled monolayers presenting nanoscale surface patterns-typically patched, striped or Janus-like domains-represent an emerging field. These systems are particularly intriguing for use in bio-nanotechnology applications, as presence of such monolayers with three-dimensional (3D) morphology provides nanoparticles with surface-dependent properties that, in turn, affect their biological behavior. Comprehensive understanding of the physicochemical interactions occurring at the interface between these versatile nanomaterials and biological systems is therefore crucial to fully exploit their potential. This review aims to explore the current state of development of such patterned, self-assembled monolayer-protected gold nanoparticles, through step-by-step analysis of their conceptual design, synthetic procedures, predicted and determined surface characteristics, interactions with and performance in biological environments, and experimental and computational methods currently employed for their investigation.

  17. Eddy current analysis by BEM utilizing loop electric and surface magnetic currents as unknowns

    International Nuclear Information System (INIS)

    Ishibashi, Kazuhisa

    2002-01-01

    The surface integral equations whose unknowns are the surface electric and magnetic currents are widely used in eddy current analysis. However, when the skin depth is thick, computational error is increased especially in obtaining electromagnetic fields near the edge of the conductor. In order to obtain the electromagnetic field accurately, we propose an approach to solve surface integral equations utilizing loop electric and surface magnetic currents as unknowns. (Author)

  18. About New Maps of Surface Currents of the World Ocean

    Science.gov (United States)

    Nikitin, O. P.; Kasyanov, S. Yu.

    2018-01-01

    Using the example of the surface currents map constructed for the Northern Atlantic on the basis of data of modern observations by means of drifting buoys, it is shown that the previously published maps of ocean surface currents, based on ship drift data, have become outdated and require an update. The influence of the bottom relief on the directions of surface layer currents is shown.

  19. Surface current observatons--Beaufort Sea, 1972

    Science.gov (United States)

    Barnes, Peter; Garlow, Richard

    1975-01-01

    Sediment transport via water and ice in the Beaufort Sea off northern Alaska is related to the movement of the surficial waters. As development proceeds along the north slope of alaska, a knowledge of the potential drift trajectories of water, ice, sediment and pollutants will be needed. In an attempt to better define the probable paths and rates of transport, 4200 surface drift cards were dropped during the U.S. Coast Guard WEBSEC cruise of August and September, 1972. The results of this release are the subject of this report. Because the data presented here will be used primarily by those interested in solving problems of transport, the emphasis has been placed on data presentation rather than a detailed analysis of the circulation. (Sinha-OEIS)

  20. Modelling Monsoons: Understanding and Predicting Current and Future Behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A; Sperber, K R; Slingo, J M; Meehl, G A; Mechoso, C R; Kimoto, M; Giannini, A

    2008-09-16

    The global monsoon system is so varied and complex that understanding and predicting its diverse behaviour remains a challenge that will occupy modellers for many years to come. Despite the difficult task ahead, an improved monsoon modelling capability has been realized through the inclusion of more detailed physics of the climate system and higher resolution in our numerical models. Perhaps the most crucial improvement to date has been the development of coupled ocean-atmosphere models. From subseasonal to interdecadal timescales, only through the inclusion of air-sea interaction can the proper phasing and teleconnections of convection be attained with respect to sea surface temperature variations. Even then, the response to slow variations in remote forcings (e.g., El Nino-Southern Oscillation) does not result in a robust solution, as there are a host of competing modes of variability that must be represented, including those that appear to be chaotic. Understanding the links between monsoons and land surface processes is not as mature as that explored regarding air-sea interactions. A land surface forcing signal appears to dominate the onset of wet season rainfall over the North American monsoon region, though the relative role of ocean versus land forcing remains a topic of investigation in all the monsoon systems. Also, improved forecasts have been made during periods in which additional sounding observations are available for data assimilation. Thus, there is untapped predictability that can only be attained through the development of a more comprehensive observing system for all monsoon regions. Additionally, improved parameterizations - for example, of convection, cloud, radiation, and boundary layer schemes as well as land surface processes - are essential to realize the full potential of monsoon predictability. Dynamical considerations require ever increased horizontal resolution (probably to 0.5 degree or higher) in order to resolve many monsoon features

  1. Surface CUrrents from a Diagnostic model (SCUD): Pacific

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SCUD data product is an estimate of upper-ocean velocities computed from a diagnostic model (Surface CUrrents from a Diagnostic model). This model makes daily...

  2. Concentration polarization, surface currents, and bulk advection in a microchannel

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present a comprehensive analysis of salt transport and overlimiting currents in a microchannel during concentration polarization. We have carried out full numerical simulations of the coupled Poisson-Nernst-Planck-Stokes problem governing the transport and rationalized the behavior of the syst...... as in the limit of negligible surface charge. By including the effects of diffusion and advection in the diffuse part of the electric double layers, we extend a recently published analytical model of overlimiting current due to surface conduction....

  3. Prediction of current distribution in a molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Sampath, V.; Selman, J.R.; Sammells, A.F.

    1978-01-01

    A mathematical model has been developed to predict the performance of a molten carbonate fuel cell as a function of anode and cathode gas compositions, gas flow rates, and polarization characteristics. The effect of gas flow modes such as crossflow and coflow and the effect of higher pressures on the current distribution are studied. The predicted polarization curves agree well with the experimentally generated polarization curves. Conditions for incorporating a microscopic porous electrode model into the overall model development are briefly outlined.

  4. An Improved Model Predictive Current Controller of Switched Reluctance Machines Using Time-Multiplexed Current Sensor.

    Science.gov (United States)

    Li, Bingchu; Ling, Xiao; Huang, Yixiang; Gong, Liang; Liu, Chengliang

    2017-05-17

    This paper presents a fixed-switching-frequency model predictive current controller using multiplexed current sensor for switched reluctance machine (SRM) drives. The converter was modified to distinguish currents from simultaneously excited phases during the sampling period. The only current sensor installed in the converter was time division multiplexing for phase current sampling. During the commutation stage, the control steps of adjacent phases were shifted so that sampling time was staggered. The maximum and minimum duty ratio of pulse width modulation (PWM) was limited to keep enough sampling time for analog-to-digital (A/D) conversion. Current sensor multiplexing was realized without complex adjustment of either driver circuit nor control algorithms, while it helps to reduce the cost and errors introduced in current sampling due to inconsistency between sensors. The proposed controller is validated by both simulation and experimental results with a 1.5 kW three-phase 12/8 SRM. Satisfied current sampling is received with little difference compared with independent phase current sensors for each phase. The proposed controller tracks the reference current profile as accurately as the model predictive current controller with independent phase current sensors, while having minor tracking errors compared with a hysteresis current controller.

  5. Simplified Approach to Predicting Rough Surface Transition

    Science.gov (United States)

    Boyle, Robert J.; Stripf, Matthias

    2009-01-01

    Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consiste nt with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparison s are presented with published experimental data. Some of the data ar e for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach ta ken in this analysis is to treat the roughness in a statistical sense , consistent with what would be obtained from blades measured after e xposure to actual engine environments. An approach is given to determ ine the equivalent sand grain roughness from the statistics of the re gular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test co nditions. Additional comparisons are made with experimental heat tran sfer data, where the roughness geometries are both regular as well a s statistical. Using the developed analysis, heat transfer calculatio ns are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.

  6. The prediction of the hydrodynamic performance of tidal current turbines

    International Nuclear Information System (INIS)

    Xiao, B Y; Zhou, L J; Xiao, Y X; Wang, Z W

    2013-01-01

    Nowadays tidal current energy is considered to be one of the most promising alternative green energy resources and tidal current turbines are used for power generation. Prediction of the open water performance around tidal turbines is important for the reason that it can give some advice on installation and array of tidal current turbines. This paper presents numerical computations of tidal current turbines by using a numerical model which is constructed to simulate an isolated turbine. This paper aims at studying the installation of marine current turbine of which the hydro-environmental impacts influence by means of numerical simulation. Such impacts include free-stream velocity magnitude, seabed and inflow direction of velocity. The results of the open water performance prediction show that the power output and efficiency of marine current turbine varies from different marine environments. The velocity distribution should be clearly and the suitable unit installation depth and direction be clearly chosen, which can ensure the most effective strategy for energy capture before installing the marine current turbine. The findings of this paper are expected to be beneficial in developing tidal current turbines and array in the future

  7. Flux surface shape and current profile optimization in tokamaks

    International Nuclear Information System (INIS)

    Dobrott, D.R.; Miller, R.L.

    1977-01-01

    Axisymmetric tokamak equilibria of noncircular cross section are analyzed numerically to study the effects of flux surface shape and current profile on ideal and resistive interchange stability. Various current profiles are examined for circles, ellipses, dees, and doublets. A numerical code separately analyzes stability in the neighborhood of the magnetic axis and in the remainder of the plasma using the criteria of Mercier and Glasser, Greene, and Johnson. Results are interpreted in terms of flux surface averaged quantities such as magnetic well, shear, and the spatial variation in the magnetic field energy density over the cross section. The maximum stable β is found to vary significantly with shape and current profile. For current profiles varying linearly with poloidal flux, the highest β's found were for doublets. Finally, an algorithm is presented which optimizes the current profile for circles and dees by making the plasma everywhere marginally stable

  8. Prediction and Migration of Surface-related Resonant Multiples

    KAUST Repository

    Guo, Bowen

    2015-08-19

    Surface-related resonant multiples can be migrated to achieve better resolution than migrating primary reflections. We now derive the formula for migrating surface-related resonant multiples, and show its super-resolution characteristics. Moreover, a method is proposed to predict surface-related resonant multiples with zero-offset primary reflections. The prediction can be used to indentify and extract the true resonant multiple from other events. Both synthetic and field data are used to validate this prediction.

  9. Mapping the Agulhas Current from space: an assessment of ASAR surface current velocities

    CSIR Research Space (South Africa)

    Rouault, MJ

    2010-10-01

    Full Text Available Over 2 years of surface current information collected in the Agulhas Current region and derived from the Doppler centroid anomalies of Envisat’s advanced synthetic aperture radar (ASAR) are examined. The sources of errors and potential use of ASAR...

  10. Transient eddy currents on finite plane and toroidal conducting surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weissenburger, D.W.; Christensen, U.R.

    1979-04-01

    this report applies a previously presented mesh analysis method to calculate transient eddy currents in conducting surfaces. Example calculations are presented for a planar conducting sheet of finite dimensions and also for a toroidal conducting surface which represents the vacuum vessel of the TFTR. For the toroidal sheet, branch inductances are initially calculated by num erically integrating the vector potential function, then the branch matrix is transformed into a mesh matrix. For the flat sheet, an analytic expression is given which enables direct calculation of the mesh inductance matrix. Streamline plots of the eddy current distributions are shown at successive time steps for each example.

  11. Deterministic prediction of surface wind speed variations

    Directory of Open Access Journals (Sweden)

    G. V. Drisya

    2014-11-01

    Full Text Available Accurate prediction of wind speed is an important aspect of various tasks related to wind energy management such as wind turbine predictive control and wind power scheduling. The most typical characteristic of wind speed data is its persistent temporal variations. Most of the techniques reported in the literature for prediction of wind speed and power are based on statistical methods or probabilistic distribution of wind speed data. In this paper we demonstrate that deterministic forecasting methods can make accurate short-term predictions of wind speed using past data, at locations where the wind dynamics exhibit chaotic behaviour. The predictions are remarkably accurate up to 1 h with a normalised RMSE (root mean square error of less than 0.02 and reasonably accurate up to 3 h with an error of less than 0.06. Repeated application of these methods at 234 different geographical locations for predicting wind speeds at 30-day intervals for 3 years reveals that the accuracy of prediction is more or less the same across all locations and time periods. Comparison of the results with f-ARIMA model predictions shows that the deterministic models with suitable parameters are capable of returning improved prediction accuracy and capturing the dynamical variations of the actual time series more faithfully. These methods are simple and computationally efficient and require only records of past data for making short-term wind speed forecasts within practically tolerable margin of errors.

  12. The current state of bearing surfaces in total hip replacement.

    Science.gov (United States)

    Rajpura, A; Kendoff, D; Board, T N

    2014-02-01

    We reviewed the literature on the currently available choices of bearing surface in total hip replacement (THR). We present a detailed description of the properties of articulating surfaces review the understanding of the advantages and disadvantages of existing bearing couples. Recent technological developments in the field of polyethylene and ceramics have altered the risk of fracture and the rate of wear, although the use of metal-on-metal bearings has largely fallen out of favour, owing to concerns about reactions to metal debris. As expected, all bearing surface combinations have advantages and disadvantages. A patient-based approach is recommended, balancing the risks of different options against an individual's functional demands.

  13. Historical Trust Levels Predict Current Welfare State Design

    DEFF Research Database (Denmark)

    Bergh, Andreas; Bjørnskov, Christian

    Using cross-sectional data for 76 countries, we apply instrumental variable techniques based on pronoun drop, temperature and monarchies to demonstrate that historical trust levels predict several indicators of current welfare state design, including universalism and high levels of regulatory...... freedom. We argue that high levels of trust and trustworthiness are necessary, but not sufficient, conditions for societies to develop successful universal welfare states that would otherwise be highly vulnerable to free riding and fraudulent behavior. Our results do not exclude positive feedback from...... welfare state universalism to individual trust, although we claim that the important causal link runs from historically trust levels to current welfare state design....

  14. Research on Predicting Drive Current of Shipborne Satcom Antenna

    Directory of Open Access Journals (Sweden)

    Kong Jinping

    2015-01-01

    Full Text Available Predicting the effect of antenna wind load on servo system precisely is meaningful to ensure the safety of satcom antenna on operation, which can avoid overload operation. In this paper, the computational fluid dynamics is used to proceed numerical computation on the pressure distribution of the reflector and torque of drive shaft under different wind speed, windward angle and angle of pitch of the antenna. The simulation model is built under MATLAB/Simulink simulation environment, and the drive current of the antenna servo system is analyzed under wind load effect and ship swing. Then, a method of predicting drive current of antenna servo system according to the wind speed, wind direction and attitude of the antenna is concluded. And this method is verified by simulation at last.

  15. Surface Current Measurements In Terra Nova Bay By Hf Radar

    Science.gov (United States)

    Flocco, D.; Falco, P.; Wadhams, P.; Spezie, G.

    We present the preliminary results of a field experiment carried out within frame- work of the CLIMA project of the Italian National Programme for Antarctic Research (PNRA) and in cooperation with the Scott Polar Research Institute of Cambridge. Dur- ing the second period (02/12/1999-23/01/2000) of the XV Italian expedition a coastal radar was used to characterize the current field in the area of Terra Nova Bay (TNB). One of the aims of the CLIMA (Climatic Long-term Interactions for the Mass balance in Antarctica) project is to determine the role of the polynya in the sea ice mass bal- ance, water structure and local climate. The OSCR-II experiment was planned in order to provide surface current measurements in the area of TNB polynya, one of the most important coastal polynya of the Ross Sea. OSCR (Ocean Surface Current Radar) is a shore based, remote sensing system designed to measure sea surface currents in coastal waters. Two radar sites (a master and a slave) provide with radial current mea- surements; data combined from both sites yield the total current vector. Unfortunately the master and slave stations did not work together throughout the whole period of the experiment. A description of the experiment and a discussion of the results, will be proposed.

  16. Surface Currents and Winds at the Delaware Bay Mouth

    Energy Technology Data Exchange (ETDEWEB)

    Muscarella, P A; Barton, N P; Lipphardt, B L; Veron, D E; Wong, K C; Kirwan, A D

    2011-04-06

    Knowledge of the circulation of estuaries and adjacent shelf waters has relied on hydrographic measurements, moorings, and local wind observations usually removed from the region of interest. Although these observations are certainly sufficient to identify major characteristics, they lack both spatial resolution and temporal coverage. High resolution synoptic observations are required to identify important coastal processes at smaller scales. Long observation periods are needed to properly sample low-frequency processes that may also be important. The introduction of high-frequency (HF) radar measurements and regional wind models for coastal studies is changing this situation. Here we analyze synoptic, high-resolution surface winds and currents in the Delaware Bay mouth over an eight-month period (October 2007 through May 2008). The surface currents were measured by two high-frequency radars while the surface winds were extracted from a data-assimilating regional wind model. To illustrate the utility of these monitoring tools we focus on two 45-day periods which previously were shown to present contrasting pictures of the circulation. One, the low-outflow period is from 1 October through 14 November 2007; the other is the high-outflow period from 3 March through 16 April 2008. The large-scale characteristics noted by previous workers are clearly corroborated. Specifically the M2 tide dominates the surface currents, and the Delaware Bay outflow plume is clearly evident in the low frequency currents. Several new aspects of the surface circulation were also identified. These include a map of the spatial variability of the M2 tide (validating an earlier model study), persistent low-frequency cross-mouth flow, and a rapid response of the surface currents to a changing wind field. However, strong wind episodes did not persist long enough to set up a sustained Ekman response.

  17. Surface current equilibria from a geometric point of view

    International Nuclear Information System (INIS)

    Kaiser, R.; Salat, A.

    1993-04-01

    This paper addresses the inverse problem of the existence of surface current MHD equilibria in toroidal geometry with vanishing magnetic field inside. Inverse means that the plasma-vacuum interface rather than the external wall or conductors are given and the latter remain to be determined. This makes a reformulation of the problem possible in geometric terms: What toroidal surfaces with analytic parameterization allow a simple analytic covering by geodesics? If such a covering by geodesics (field lines) exists, their orthogonal trajectories (current lines) also form a simple covering and are described by a function satisfying a nonlinear partial differential equation of the Hamilton-Jacobi type whose coefficients are combinations of the metric elements of the surface. All known equilibria - equilibria with zero and infinite rotational transform and the symmetric ones in the case of finite rotational transform - turn out to be solutions of separable cases of that equation and allow a unified description if the toroidal surface is parametrized in the moving trihedral associated with a closed curve. Analogously to volume current equilibria, the only continuous symmetries compatible with separability are plane, helical and axial symmetry. In the nonseparable case numerical evidence is presented for cases with chaotic behaviour of geodesics, thus restricting possible equilibria for these surfaces. For weak deviation from axisymmetry KAM-type behaviour is observed, i.e. destruction of geodesic coverings with a low rational rotational transform and preservation of those with irrational rotational transform. A previous attempt to establish three-dimensional surface current equilibria on the basis of the KAM theorem is rejected as incomplete, and a complete proof of the existence of equilibria in the weakly nonaxisymmetric case, based on the twist theorem for mappings, is given. Finally, for a certain class of strong deviations from axisymmetry an analytic criterion is

  18. Nearshore surface current patterns in the Tsitsikamma National Park ...

    African Journals Online (AJOL)

    The pattern of surface currents in the Tsitsikamma National Park, South Africa, was studied with holey-sock drogues released in batches of up to four at a time, from 1996 and 1998. Drogues were left to drift for either 6 or 24 h, while recording position and time. The majority of drogue movements were longshore, either ...

  19. Evaluation of OSCAR ocean surface current product in the tropical ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 122; Issue 1. Evaluation of OSCAR ocean surface current product in the tropical Indian Ocean using in situ data. Rajesh Sikhakolli Rashmi Sharma Sujit Basu B S Gohil Abhijit Sarkar K V S R Prasad. Volume 122 Issue 1 February 2013 pp 187-199 ...

  20. Evaluation of OSCAR ocean surface current product in the tropical ...

    Indian Academy of Sciences (India)

    combined fashion, have contributed to the superior performance of the present algorithm for generat- ing ocean surface current. Validation and error analysis of the OSCAR pro- ..... EC (figure 4) through the appearance of strong semiannual periodicity. The SEC peaks in July, the peak being smoother in OSCAR climatology.

  1. Evaluation of OSCAR ocean surface current product in the tropical ...

    Indian Academy of Sciences (India)

    (Johnson et al. 2007). The OSCAR product is, however, a global product. Thus there is a pressing need to validate this product in the other basins of the world ocean, e.g., in the Indian Ocean. The present study is motivated by this need. In the present study, monthly climatology of OSCAR ocean surface currents in the TIO ...

  2. Origin and evolution of surface spin current in topological insulators

    Science.gov (United States)

    Dankert, André; Bhaskar, Priyamvada; Khokhriakov, Dmitrii; Rodrigues, Isabel H.; Karpiak, Bogdan; Kamalakar, M. Venkata; Charpentier, Sophie; Garate, Ion; Dash, Saroj P.

    2018-03-01

    The Dirac surface states of topological insulators offer a unique possibility for creating spin polarized charge currents due to the spin-momentum locking. Here we demonstrate that the control over the bulk and surface contribution is crucial to maximize the charge-to-spin conversion efficiency. We observe an enhancement of the spin signal due to surface-dominated spin polarization while freezing out the bulk conductivity in semiconducting Bi1.5Sb0.5Te1.7Se1.3 below 100 K . Detailed measurements up to room temperature exhibit a strong reduction of the magnetoresistance signal between 2 and100 K , which we attribute to the thermal excitation of bulk carriers and to the electron-phonon coupling in the surface states. The presence and dominance of this effect up to room temperature is promising for spintronic science and technology.

  3. Molecular Dynamics Simulations for Predicting Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2014-06-01

    Full Text Available The investigation of wetting of a solid surface by a liquid provides important insights; the contact angle of a liquid droplet on a surface provides a quantitative measurement of this interaction and the degree of attraction or repulsion of that liquid type by the solid surface. Molecular dynamics (MD simulations are a useful way to examine the behavior of liquids on solid surfaces on a nanometer scale. Thus, we surveyed the state of this field, beginning with the fundamentals of wetting calculations to an examination of the different MD methodologies used. We highlighted some of the advantages and disadvantages of the simulations, and look to the future of computer modeling to understand wetting and other liquid-solid interaction phenomena.

  4. Ion current prediction model considering columnar recombination in alpha radioactivity measurement using ionized air transportation

    International Nuclear Information System (INIS)

    Naito, Susumu; Hirata, Yosuke; Izumi, Mikio; Sano, Akira; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi

    2007-01-01

    We present a reinforced ion current prediction model in alpha radioactivity measurement using ionized air transportation. Although our previous model explained the qualitative trend of the measured ion current values, the absolute values of the theoretical curves were about two times as large as the measured values. In order to accurately predict the measured values, we reinforced our model by considering columnar recombination and turbulent diffusion, which affects columnar recombination. Our new model explained the considerable ion loss in the early stage of ion diffusion and narrowed the gap between the theoretical and measured values. The model also predicted suppression of ion loss due to columnar recombination by spraying a high-speed air flow near a contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, we quantitatively clarified the theoretical relation between alpha radioactivity and ion current in laminar flow and turbulent pipe flow. (author)

  5. Multi-Objective Predictive Balancing Control of Battery Packs Based on Predictive Current

    Directory of Open Access Journals (Sweden)

    Wenbiao Li

    2016-04-01

    Full Text Available Various balancing topology and control methods have been proposed for the inconsistency problem of battery packs. However, these strategies only focus on a single objective, ignore the mutual interaction among various factors and are only based on the external performance of the battery pack inconsistency, such as voltage balancing and state of charge (SOC balancing. To solve these problems, multi-objective predictive balancing control (MOPBC based on predictive current is proposed in this paper, namely, in the driving process of an electric vehicle, using predictive control to predict the battery pack output current the next time. Based on this information, the impact of the battery pack temperature caused by the output current can be obtained. Then, the influence is added to the battery pack balancing control, which makes the present degradation, temperature, and SOC imbalance achieve balance automatically due to the change of the output current the next moment. According to MOPBC, the simulation model of the balancing circuit is built with four cells in Matlab/Simulink. The simulation results show that MOPBC is not only better than the other traditional balancing control strategies but also reduces the energy loss in the balancing process.

  6. Drought Predictability and Prediction in a Changing Climate: Assessing Current Predictive Knowledge and Capabilities, User Requirements and Research Priorities

    Science.gov (United States)

    Schubert, Siegfried

    2011-01-01

    Drought is fundamentally the result of an extended period of reduced precipitation lasting anywhere from a few weeks to decades and even longer. As such, addressing drought predictability and prediction in a changing climate requires foremost that we make progress on the ability to predict precipitation anomalies on subseasonal and longer time scales. From the perspective of the users of drought forecasts and information, drought is however most directly viewed through its impacts (e.g., on soil moisture, streamflow, crop yields). As such, the question of the predictability of drought must extend to those quantities as well. In order to make progress on these issues, the WCRP drought information group (DIG), with the support of WCRP, the Catalan Institute of Climate Sciences, the La Caixa Foundation, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the National Science Foundation, has organized a workshop to focus on: 1. User requirements for drought prediction information on sub-seasonal to centennial time scales 2. Current understanding of the mechanisms and predictability of drought on sub-seasonal to centennial time scales 3. Current drought prediction/projection capabilities on sub-seasonal to centennial time scales 4. Advancing regional drought prediction capabilities for variables and scales most relevant to user needs on sub-seasonal to centennial time scales. This introductory talk provides an overview of these goals, and outlines the occurrence and mechanisms of drought world-wide.

  7. Robust Prediction of High Lift Using Surface Vorticity, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — FlightStream has been developed a fast, accurate, aerodynamic prediction code based on vorticity computations on the surface of an aircraft. The code, though still a...

  8. Enhanced Prediction of Gear Tooth Surface Fatigue Life, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Sentient will develop an enhanced prediction of gear tooth surface fatigue life with rigorous analysis of the tribological phenomena that contribute to pitting...

  9. Ka-band Doppler Scatterometer for Measurements of Ocean Vector Winds and Surface Currents

    Data.gov (United States)

    National Aeronautics and Space Administration — Ocean surface currents impact heat transport, surface momentum and gas fluxes, ocean productivity and marine biological communities. Ocean currents also have social...

  10. Nonreciprocal Oersted field contribution to the current-induced frequency shift of magnetostatic surface waves

    Science.gov (United States)

    Haidar, Mohammad; Bailleul, Matthieu; Kostylev, Mikhail; Lao, Yuyang

    2014-03-01

    The influence of an electrical current on the propagation of magnetostatic surface waves is investigated in a relatively thick (40 nm) permalloy film both experimentally and theoretically. Contrary to previously studied thinner films where the dominating effect is the current-induced spin-wave Doppler shift, the magnetic field generated by the current (Oersted field) is found to induce a strong nonreciprocal frequency shift which overcompensates the Doppler shift. The measured current-induced frequency shift is in agreement with the developed theory. The theory relates the sign of the frequency shift to the spin-wave modal profiles. The good agreement between the experiment and the theory confirms a recent prediction of a counterintuitive mode localization for magnetostatic surface waves in the dipole-exchange regime.

  11. Surface waves on currents with arbitrary vertical shear

    Science.gov (United States)

    Smeltzer, Benjamin K.; Ellingsen, Simen Å.

    2017-04-01

    We study dispersion properties of linear surface gravity waves propagating in an arbitrary direction atop a current profile of depth-varying magnitude using a piecewise linear approximation and develop a robust numerical framework for practical calculation. The method has been much used in the past for the case of waves propagating along the same axis as the background current, and we herein extend and apply it to problems with an arbitrary angle between the wave propagation and current directions. Being valid for all wavelengths without loss of accuracy, the scheme is particularly well suited to solve problems involving a broad range of wave vectors, such as ship waves and Cauchy-Poisson initial value problems. We examine the group and phase velocities over different wavelength regimes and current profiles, highlighting characteristics due to the depth-variable vorticity. We show an example application to ship waves on an arbitrary current profile and demonstrate qualitative differences in the wake patterns between concave down and concave up profiles when compared to a constant shear profile with equal depth-averaged vorticity. We also discuss the nature of additional solutions to the dispersion relation when using the piecewise-linear model. These are vorticity waves, drifting vortical structures which are artifacts of the piecewise model. They are absent for a smooth profile and are spurious in the present context.

  12. Predicting the Wear of High Friction Surfacing Aggregate

    Directory of Open Access Journals (Sweden)

    David Woodward

    2017-05-01

    Full Text Available High friction surfacing (HFS is a specialist type of road coating with very high skid resistance. It is used in the UK at locations where there is significant risk of serious or fatal accidents. This paper considers the aggregate used in HFS. Calcined bauxite is the only aggregate that provides the highest levels of skid resistance over the longest period. No naturally occurring aggregate has been found to give a comparable level of in-service performance. This paper reviews the historical development of HFS in the UK relating to aggregate. In-service performance is predicted in the laboratory using the Wear test which subjects test specimens to an estimated 5–8 years simulated trafficking. Examples are given of Wear test data. They illustrate why calcined bauxite performs better than natural aggregate. They show how the amount of calcined bauxite can be reduced by blending with high skid resistant natural aggregates. Data from the Wear test can be related to every HFS laboratory experiment and road trial carried out in the UK for over the last 50 years. Anyone considering the prediction of HFS performance needs to carefully consider the data given in this paper with any other test method currently being considered or used to investigate HFS.

  13. Predicting 3D lip shapes using facial surface EMG

    NARCIS (Netherlands)

    Eskes, Merijn; van Alphen, Maarten J. A.; Balm, Alfons J. M.; Smeele, Ludi E.; Brandsma, Dieta; van der Heijden, Ferdinand

    2017-01-01

    Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and

  14. Brain surface motion imaging to predict adhesions between meningiomas and the brain surface

    Energy Technology Data Exchange (ETDEWEB)

    Taoka, Toshiaki; Yamatani, Yuya; Akashi, Toshiaki; Miyasaka, Toshiteru; Emura, Tomoko; Kichikawa, Kimihiko [Nara Medical University, Department of Radiology, Nara (Japan); Yamada, Syuichi; Nakase, Hiroyuki [Nara Medical University, Department of Neurosurgery, Nara (Japan)

    2010-11-15

    ''Brain surface motion imaging'' (BSMI) is the subtraction of pulse-gated, 3D, heavily T2-weighted image of two different phases of cerebrospinal fluid (CSF) pulsation, which enables the assessment of the dynamics of brain surface pulsatile motion. The purpose of this study was to evaluate the feasibility of this imaging method for providing presurgical information about adhesions between meningiomas and the brain surface. Eighteen cases with surgically resected meningioma in whom BSMI was presurgically obtained were studied. BSMI consisted of two sets of pulse-gated, 3D, heavily T2-weighted, fast spin echo scans. Images of the systolic phase and the diastolic phase were obtained, and subtraction was performed with 3D motion correction. We analyzed the presence of band-like texture surrounding the tumor and judged the degree of motion discrepancy as ''total,'' ''partial,'' or ''none.'' The correlation between BSMI and surgical findings was evaluated. For cases with partial adhesions, agreements in the locations of the adhesions were also evaluated. On presurgical BSMI, no motion discrepancy was seen in eight cases, partial in six cases, and total in four cases. These presurgical predictions about adhesions and surgical findings agreed in 13 cases (72.2%). The locations of adhesions agreed in five of six cases with partial adhesions. In the current study, BSMI could predict brain and meningioma adhesions correctly in 72.2% of cases, and adhesion location could also be predicted. This imaging method appears to provide presurgical information about brain/meningioma adhesions. (orig.)

  15. The prediction of BRDFs from surface profile measurements

    International Nuclear Information System (INIS)

    Church, E.L.; Takacs, P.Z.; Leonard, T.A.

    1989-01-01

    This paper discusses methods of predicting the BRDF of smooth surfaces from profile measurements of their surface finish. The conversion of optical profile data to the BRDF at the same wavelength is essentially independent of scattering models, while the conversion of mechanical measurements, and wavelength scaling in general, are model dependent. Procedures are illustrated for several surfaces, including two from the recent HeNe BRDF round robin, and results are compared with measured data. Reasonable agreement is found except for surfaces which involve significant scattering from isolated surface defects which are poorly sampled in the profile data

  16. Land surface impacts on subseasonal and seasonal predictability

    Science.gov (United States)

    Guo, Zhichang; Dirmeyer, Paul A.; DelSole, Tim

    2011-12-01

    This paper shows that realistically initialized land surface states enhance atmospheric predictability significantly out to two-to-three months during summer. The spatial structure of the impact of land initialization on atmospheric predictability can be explained by the simultaneous influence of soil moisture memory time and land surface-evapotranspiration coupling strength. A proxy for this impact based on soil moisture and evaporation anomalies is proposed. The results also show that the impact of the land surface on atmospheric predictability varies with season: enhancement of predictability is relatively small during boreal spring and autumn, and reaches a maximum during boreal summer. Remarkably, the predictability of atmospheric temperature and precipitation increases with lead time from spring to summer. This increase is diagnosed as a “transfer” of predictability from land to atmosphere: during spring, the soil moisture predictability is high, but this predictability does not impact the atmosphere due to lack of land-atmosphere coupling; during summer, the coupling increases, thereby transferring the predictability from land to atmosphere.

  17. Experimental High-Resolution Land Surface Prediction System for the Vancouver 2010 Winter Olympic Games

    Science.gov (United States)

    Belair, S.; Bernier, N.; Tong, L.; Mailhot, J.

    2008-05-01

    The 2010 Winter Olympic and Paralympic Games will take place in Vancouver, Canada, from 12 to 28 February 2010 and from 12 to 21 March 2010, respectively. In order to provide the best possible guidance achievable with current state-of-the-art science and technology, Environment Canada is currently setting up an experimental numerical prediction system for these special events. This system consists of a 1-km limited-area atmospheric model that will be integrated for 16h, twice a day, with improved microphysics compared with the system currently operational at the Canadian Meteorological Centre. In addition, several new and original tools will be used to adapt and refine predictions near and at the surface. Very high-resolution two-dimensional surface systems, with 100-m and 20-m grid size, will cover the Vancouver Olympic area. Using adaptation methods to improve the forcing from the lower-resolution atmospheric models, these 2D surface models better represent surface processes, and thus lead to better predictions of snow conditions and near-surface air temperature. Based on a similar strategy, a single-point model will be implemented to better predict surface characteristics at each station of an observing network especially installed for the 2010 events. The main advantage of this single-point system is that surface observations are used as forcing for the land surface models, and can even be assimilated (although this is not expected in the first version of this new tool) to improve initial conditions of surface variables such as snow depth and surface temperatures. Another adaptation tool, based on 2D stationnary solutions of a simple dynamical system, will be used to produce near-surface winds on the 100-m grid, coherent with the high- resolution orography. The configuration of the experimental numerical prediction system will be presented at the conference, together with preliminary results for winter 2007-2008.

  18. Extended Range Prediction of Indian Summer Monsoon: Current status

    Science.gov (United States)

    Sahai, A. K.; Abhilash, S.; Borah, N.; Joseph, S.; Chattopadhyay, R.; S, S.; Rajeevan, M.; Mandal, R.; Dey, A.

    2014-12-01

    added value to both deterministic and probability forecast compared to raw SME's and this better skill is probably flows from large spread and improved spread-error relationship. CGMME system is currently capable of generating ER prediction in real time and successfully delivering its experimental operational ER forecast of ISM for the last few years.

  19. Predictive model for ice formation on superhydrophobic surfaces.

    Science.gov (United States)

    Bahadur, Vaibhav; Mishchenko, Lidiya; Hatton, Benjamin; Taylor, J Ashley; Aizenberg, Joanna; Krupenkin, Tom

    2011-12-06

    The prevention and control of ice accumulation has important applications in aviation, building construction, and energy conversion devices. One area of active research concerns the use of superhydrophobic surfaces for preventing ice formation. The present work develops a physics-based modeling framework to predict ice formation on cooled superhydrophobic surfaces resulting from the impact of supercooled water droplets. This modeling approach analyzes the multiple phenomena influencing ice formation on superhydrophobic surfaces through the development of submodels describing droplet impact dynamics, heat transfer, and heterogeneous ice nucleation. These models are then integrated together to achieve a comprehensive understanding of ice formation upon impact of liquid droplets at freezing conditions. The accuracy of this model is validated by its successful prediction of the experimental findings that demonstrate that superhydrophobic surfaces can fully prevent the freezing of impacting water droplets down to surface temperatures of as low as -20 to -25 °C. The model can be used to study the influence of surface morphology, surface chemistry, and fluid and thermal properties on dynamic ice formation and identify parameters critical to achieving icephobic surfaces. The framework of the present work is the first detailed modeling tool developed for the design and analysis of surfaces for various ice prevention/reduction strategies. © 2011 American Chemical Society

  20. Prediction of Protein Structure Using Surface Accessibility Data.

    Science.gov (United States)

    Hartlmüller, Christoph; Göbl, Christoph; Madl, Tobias

    2016-09-19

    An approach to the de novo structure prediction of proteins is described that relies on surface accessibility data from NMR paramagnetic relaxation enhancements by a soluble paramagnetic compound (sPRE). This method exploits the distance-to-surface information encoded in the sPRE data in the chemical shift-based CS-Rosetta de novo structure prediction framework to generate reliable structural models. For several proteins, it is demonstrated that surface accessibility data is an excellent measure of the correct protein fold in the early stages of the computational folding algorithm and significantly improves accuracy and convergence of the standard Rosetta structure prediction approach. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  1. Predicting Surface Runoff from Catchment to Large Region

    Directory of Open Access Journals (Sweden)

    Hongxia Li

    2015-01-01

    Full Text Available Predicting surface runoff from catchment to large region is a fundamental and challenging task in hydrology. This paper presents a comprehensive review for various studies conducted for improving runoff predictions from catchment to large region in the last several decades. This review summarizes the well-established methods and discusses some promising approaches from the following four research fields: (1 modeling catchment, regional and global runoff using lumped conceptual rainfall-runoff models, distributed hydrological models, and land surface models, (2 parameterizing hydrological models in ungauged catchments, (3 improving hydrological model structure, and (4 using new remote sensing precipitation data.

  2. The Effect of the Leeuwin Current on Offshore Surface Gravity Waves in Southwest Western Australia

    Science.gov (United States)

    Wandres, Moritz; Wijeratne, E. M. S.; Cosoli, Simone; Pattiaratchi, Charitha

    2017-11-01

    The knowledge of regional wave regimes is critical for coastal zone planning, protection, and management. In this study, the influence of the offshore current regime on surface gravity waves on the southwest Western Australian (SWWA) continental shelf was examined. This was achieved by coupling the three dimensional, free surface, terrain-following hydrodynamic Regional Ocean Modelling System (ROMS) and the third generation wave model Simulating WAves Nearshore (SWAN) using the Coupled Ocean-Atmosphere-WaveSediment Transport (COAWST) model. Different representative states of the Leeuwin Current (LC), a strong pole-ward flowing boundary current with a persistent eddy field along the SWWA shelf edge were simulated and used to investigate their influence on different large wave events. The coupled wave-current simulations were compared to wave only simulations, which represented scenarios in the absence of a background current field. Results showed that the LC and the eddy field significantly impact SWWA waves. Significant wave heights increased (decreased) when currents were opposing (aligning with) the incoming wave directions. During a fully developed LC system significant wave heights were altered by up to ±25% and wave directions by up to ±20°. The change in wave direction indicates that the LC may modify nearshore wave dynamics and consequently alter sediment patterns. Operational regional wave forecasts and hindcasts may give flawed predictions if wave-current interaction is not properly accounted for.

  3. Linear predictability: A sea surface height case study

    Science.gov (United States)

    Sonnewald, Maike; Wunsch, Carl; Heimbach, Patrick

    2017-04-01

    A benchmark of linear predictive skill of global sea surface height (SSH or η) is presented, complementing more complicated studies of η predictive skill. Twenty years of the ECCOv4 state estimate (1992-2012) are used, fitting ARMA(n,m) models where the order is chosen by the Akaike and Bayesian Information Criteria (AIC and BIC). The prediction on the basis of monthly detrended data shows skill generally of the order of a few months, with isolated regions of twelve months or more. With the trend, the predictive skill increases, particularly in the south Pacific. Annually averaged data are also used, although the time-series are too short to assess the variability. Including a linear trend as part of the signal results in some enhanced predictability.

  4. Landform and surface attributes for prediction of rodent burrows in ...

    African Journals Online (AJOL)

    Previous studies suggest that rodent burrows, a proxy for rodent population are important for predicting plague risk areas. However, studies that link landform, surface attributes and rodent burrows in the Western Usambara Mountains in Tanzania are scanty. Therefore, this study was conducted in plague endemic area of ...

  5. BION web server: predicting non-specifically bound surface ions.

    Science.gov (United States)

    Petukh, Marharyta; Kimmet, Taylor; Alexov, Emil

    2013-03-15

    Ions are essential component of the cell and frequently are found bound to various macromolecules, in particular to proteins. A binding of an ion to a protein greatly affects protein's biophysical characteristics and needs to be taken into account in any modeling approach. However, ion's bounded positions cannot be easily revealed experimentally, especially if they are loosely bound to macromolecular surface. Here, we report a web server, the BION web server, which addresses the demand for tools of predicting surface bound ions, for which specific interactions are not crucial; thus, they are difficult to predict. The BION is easy to use web server that requires only coordinate file to be inputted, and the user is provided with various, but easy to navigate, options. The coordinate file with predicted bound ions is displayed on the output and is available for download.

  6. Predicting Nanocrystal Shape through Consideration of Surface-Ligand Interactions

    KAUST Repository

    Bealing, Clive R.

    2012-03-27

    Density functional calculations for the binding energy of oleic acid-based ligands on Pb-rich {100} and {111} facets of PbSe nanocrystals determine the surface energies as a function of ligand coverage. Oleic acid is expected to bind to the nanocrystal surface in the form of lead oleate. The Wulff construction predicts the thermodynamic equilibrium shape of the PbSe nanocrystals. The equilibrium shape is a function of the ligand surface coverage, which can be controlled by changing the concentration of oleic acid during synthesis. The different binding energy of the ligand on the {100} and {111} facets results in different equilibrium ligand coverages on the facets, and a transition in the equilibrium shape from octahedral to cubic is predicted when increasing the ligand concentration during synthesis. © 2012 American Chemical Society.

  7. Computational prediction of chemical reactions: current status and outlook.

    Science.gov (United States)

    Engkvist, Ola; Norrby, Per-Ola; Selmi, Nidhal; Lam, Yu-Hong; Peng, Zhengwei; Sherer, Edward C; Amberg, Willi; Erhard, Thomas; Smyth, Lynette A

    2018-03-03

    Over the past few decades, various computational methods have become increasingly important for discovering and developing novel drugs. Computational prediction of chemical reactions is a key part of an efficient drug discovery process. In this review, we discuss important parts of this field, with a focus on utilizing reaction data to build predictive models, the existing programs for synthesis prediction, and usage of quantum mechanics and molecular mechanics (QM/MM) to explore chemical reactions. We also outline potential future developments with an emphasis on pre-competitive collaboration opportunities. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. PREDICTION OF SURFACE ROUGHNESS IN END MILLING OPERATION OF DUPLEX STAINLESS STEEL USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    S. D. PHILIP

    2015-03-01

    Full Text Available Response surface methodology has been used to study the effects of the machining parameters such as spindle speed, feed rate and axial depth of cut on surface roughness of duplex stainless steel in end milling operation. Dry milling experiments were conducted with three levels of spindle speed, feed rate and axial depth of cut. A mathematical model has been developed to predict the surface roughness in terms of the machining parameters using Box-Behnken design response surface methodology. The adequacy of the model was verified using analysis of variance. The prediction equation shows that the feed rate is the most important factor that influences the surface roughness followed by axial depth of cut and spindle speed. The validity of the model was verified by conducting the confirmation experiment.

  9. Current knowledge about the hydrophilic and nanostructured SLActive surface

    Directory of Open Access Journals (Sweden)

    Wennerberg A

    2011-09-01

    Full Text Available Ann Wennerberg1,2, Silvia Galli2, Tomas Albrektsson2,31Department of Prosthodontics, Malmö University, Malmö, 2Department of Biomaterials, Gothenburg University, Gothenburg, 3Department of Materials Science and Technology, Malmö University, SwedenAbstract: This review summarizes the present documentation for the SLActive surface, a hydrophilic and nanostructured surface produced by Straumann Company in Switzerland, and covers the results from 15 in vitro, 17 in vivo, and 16 clinical studies. The SLActive surface is a development of the large grit-blasted and acid-etched SLA surface, and is further processed to a high degree of hydrophilicity. In general, the in vitro and in vivo studies of the SLActive surface demonstrate a stronger cell and bone tissue response than for the predecessor, the SLA surface, produced by the same company. However, in most studies, this difference disappears after 6–8 weeks. In the clinical studies, a stronger bone response was reported for the SLActive surface during the early healing phase when compared with the SLA surface. However, the later biological response was quite similar for the two surfaces and both demonstrated very good clinical results.Keywords: SLActive, surface, in vitro, in vivo, clinical results

  10. Surface acoustic wave probe implant for predicting epileptic seizures

    Science.gov (United States)

    Gopalsami, Nachappa [Naperville, IL; Kulikov, Stanislav [Sarov, RU; Osorio, Ivan [Leawood, KS; Raptis, Apostolos C [Downers Grove, IL

    2012-04-24

    A system and method for predicting and avoiding a seizure in a patient. The system and method includes use of an implanted surface acoustic wave probe and coupled RF antenna to monitor temperature of the patient's brain, critical changes in the temperature characteristic of a precursor to the seizure. The system can activate an implanted cooling unit which can avoid or minimize a seizure in the patient.

  11. Predicting the extent of succulent thicket under current and future ...

    African Journals Online (AJOL)

    Using data from the distribution records of the facultative CAM succulent shrub Portulacaria afra, and high resolution climate response surfaces, we developed a spatially explicit model of the potential distribution of the species in the Thicket Biome of the eastern and southern Cape, South Africa. The resultant map shows a ...

  12. Current Developments in Antimicrobial Surface Coatings for Biomedical Applications

    NARCIS (Netherlands)

    Swartjes, J. J. T. M.; Sharma, P. K.; van Kooten, T. G.; van der Mei, H. C.; Mahmoudi, M.; Busscher, H. J.; Rochford, E. T. J.

    2015-01-01

    Bacterial adhesion and subsequent biofilm formation on material surfaces represent a serious problem in society from both an economical and health perspective. Surface coating approaches to prevent bacterial adhesion and biofilm formation are of increased importance due to the increasing prevalence

  13. On the predictability of land surface fluxes from meteorological variables

    Science.gov (United States)

    Haughton, Ned; Abramowitz, Gab; Pitman, Andy J.

    2018-01-01

    Previous research has shown that land surface models (LSMs) are performing poorly when compared with relatively simple empirical models over a wide range of metrics and environments. Atmospheric driving data appear to provide information about land surface fluxes that LSMs are not fully utilising. Here, we further quantify the information available in the meteorological forcing data that are used by LSMs for predicting land surface fluxes, by interrogating FLUXNET data, and extending the benchmarking methodology used in previous experiments. We show that substantial performance improvement is possible for empirical models using meteorological data alone, with no explicit vegetation or soil properties, thus setting lower bounds on a priori expectations on LSM performance. The process also identifies key meteorological variables that provide predictive power. We provide an ensemble of empirical benchmarks that are simple to reproduce and provide a range of behaviours and predictive performance, acting as a baseline benchmark set for future studies. We reanalyse previously published LSM simulations and show that there is more diversity between LSMs than previously indicated, although it remains unclear why LSMs are broadly performing so much worse than simple empirical models.

  14. Can foot anthropometric measurements predict dynamic plantar surface contact area?

    Directory of Open Access Journals (Sweden)

    Collins Natalie

    2009-10-01

    Full Text Available Abstract Background Previous studies have suggested that increased plantar surface area, associated with pes planus, is a risk factor for the development of lower extremity overuse injuries. The intent of this study was to determine if a single or combination of foot anthropometric measures could be used to predict plantar surface area. Methods Six foot measurements were collected on 155 subjects (97 females, 58 males, mean age 24.5 ± 3.5 years. The measurements as well as one ratio were entered into a stepwise regression analysis to determine the optimal set of measurements associated with total plantar contact area either including or excluding the toe region. The predicted values were used to calculate plantar surface area and were compared to the actual values obtained dynamically using a pressure sensor platform. Results A three variable model was found to describe the relationship between the foot measures/ratio and total plantar contact area (R2 = 0.77, p R2 = 0.76, p Conclusion The results of this study indicate that the clinician can use a combination of simple, reliable, and time efficient foot anthropometric measurements to explain over 75% of the plantar surface contact area, either including or excluding the toe region.

  15. Seasonal sea surface temperature anomaly prediction for coastal ecosystems

    Science.gov (United States)

    Stock, Charles A.; Pegion, Kathy; Vecchi, Gabriel A.; Alexander, Michael A.; Tommasi, Desiree; Bond, Nicholas A.; Fratantoni, Paula S.; Gudgel, Richard G.; Kristiansen, Trond; O'Brien, Todd D.; Xue, Yan; Yang, Xiasong

    2015-09-01

    Sea surface temperature (SST) anomalies are often both leading indicators and important drivers of marine resource fluctuations. Assessment of the skill of SST anomaly forecasts within coastal ecosystems accounting for the majority of global fish yields, however, has been minimal. This reflects coarse global forecast system resolution and past emphasis on the predictability of ocean basin-scale SST variations. This paper assesses monthly to inter-annual SST anomaly predictions in coastal "Large Marine Ecosystems" (LMEs). We begin with an analysis of 7 well-observed LMEs adjacent to the United States and then examine how mechanisms responsible for prediction skill in these systems are reflected in predictions for LMEs globally. Historical SST anomaly estimates from the 1/4° daily Optimal Interpolation Sea Surface Temperature reanalysis (OISST.v2) were first found to be highly consistent with in-situ measurements for 6 of the 7 U.S. LMEs. Thirty years of retrospective forecasts from climate forecast systems developed at NOAA's Geophysical Fluid Dynamics Laboratory (CM2.5-FLOR) and the National Center for Environmental Prediction (CFSv2) were then assessed against OISST.v2. Forecast skill varied widely by LME, initialization month, and lead but there were many cases of high skill that also exceeded that of a persistence forecast, some at leads greater than 6 months. Mechanisms underlying skill above persistence included accurate simulation of (a) seasonal transitions between less predictable locally generated and more predictable basin-scale SST variability; (b) seasonal transitions between different basin-scale influences; (c) propagation of SST anomalies across seasons through sea ice; and (d) re-emergence of previous anomalies upon the breakdown of summer stratification. Globally, significant skill above persistence across many tropical systems arises via mechanisms (a) and (b). Combinations of all four mechanisms contribute to less prevalent but nonetheless

  16. Factors Predicting the Ocular Surface Response to Desiccating Environmental Stress

    Science.gov (United States)

    Alex, Anastasia; Edwards, Austin; Hays, J. Daniel; Kerkstra, Michelle; Shih, Amanda; de Paiva, Cintia S.; Pflugfelder, Stephen C.

    2013-01-01

    Purpose. To identify factors predicting the ocular surface response to experimental desiccating stress. Methods. The ocular surfaces of both eyes of 15 normal and 10 dry eye subjects wearing goggles were exposed to a controlled desiccating environment (15%–25% relative humidity and 2–5 L/min airflow) for 90 minutes. Eye irritation symptoms, blink rate, tear meniscus dimensions, noninvasive (RBUT) and invasive tear break-up time, and corneal fluorescein and conjunctival lissamine green-dye staining were recorded before and after desiccating stress. Pre- and postexposure measurements were compared, and Pearson correlations between clinical parameters before and after desiccating stress were calculated. Results. Corneal and conjunctival dye staining significantly increased in all subjects following 90-minute exposure to desiccating environment, and the magnitude of change was similar in normal and dry eye subjects; except superior cornea staining was greater in dry eye. Irritation severity in the desiccating environment was associated with baseline dye staining, baseline tear meniscus height, and blink rate after 45 minutes. Desiccation-induced change in corneal fluorescein staining was inversely correlated to baseline tear meniscus width, whereas change in total ocular surface dye staining was inversely correlated to baseline dye staining, RBUT, and tear meniscus height and width. Blink rate from 30 to 90 minutes in desiccating environment was higher in the dry eye than normal group. Blink rate significantly correlated to baseline corneal fluorescein staining and environmental-induced change in corneal fluorescein staining. Conclusions. Ocular surface dye staining increases in response to desiccating stress. Baseline ocular surface dye staining, tear meniscus height, and blink rate predict severity of ocular surface dye staining following exposure to a desiccating environment. PMID:23572103

  17. Grade and Recovery Prediction for Eddy Current Separation Processes

    NARCIS (Netherlands)

    Rem, P.C.; Beunder, E.M.; Kuilman, W.

    1998-01-01

    Grade and recovery of eddy current separation can be estimated on the basis of trajectory simulations for particles of simple shapes. In order to do so, the feed is characterized in terms of a small set of test-particles, each test-particle representing a fraction of the feed of a given size, shape

  18. Current Developments in Antimicrobial Surface Coatings for Biomedical Applications.

    Science.gov (United States)

    Swartjes, J J T M; Sharma, P K; van Kooten, T G; van der Mei, H C; Mahmoudi, M; Busscher, H J; Rochford, E T J

    2015-01-01

    Bacterial adhesion and subsequent biofilm formation on material surfaces represent a serious problem in society from both an economical and health perspective. Surface coating approaches to prevent bacterial adhesion and biofilm formation are of increased importance due to the increasing prevalence of antibiotic resistant bacterial strains. Effective antimicrobial surface coatings can be based on an anti-adhesive principle that prevents bacteria to adhere, or on bactericidal strategies, killing organisms either before or after contact is made with the surface. Many strategies, however, implement a multifunctional approach that incorporates both of these mechanisms. For anti-adhesive strategies, the use of polymer chains, or hydrogels is preferred, although recently a new class of super-hydrophobic surfaces has been described which demonstrate improved anti-adhesive activity. In addition, bacterial killing can be achieved using antimicrobial peptides, antibiotics, chitosan or enzymes directly bound, tethered through spacer-molecules or encased in biodegradable matrices, nanoparticles and quaternary ammonium compounds. Notwithstanding the ubiquitous nature of the problem of microbial colonization of material surfaces, this review focuses on the recent developments in antimicrobial surface coatings with respect to biomaterial implants and devices. In this biomedical arena, to rank the different coating strategies in order of increasing efficacy is impossible, since this depends on the clinical application aimed for and whether expectations are short- or long term. Considering that the era of antibiotics to control infectious biofilms will eventually come to an end, the future for biofilm control on biomaterial implants and devices is likely with surface-associated modifications that are non-antibiotic related.

  19. Observations of Near-Surface Current Shear Help Describe Oceanic Oil and Plastic Transport

    Science.gov (United States)

    Laxague, Nathan J. M.; Ö-zgökmen, Tamay M.; Haus, Brian K.; Novelli, Guillaume; Shcherbina, Andrey; Sutherland, Peter; Guigand, Cédric M.; Lund, Björn; Mehta, Sanchit; Alday, Matias; Molemaker, Jeroen

    2018-01-01

    Plastics and spilled oil pose a critical threat to marine life and human health. As a result of wind forcing and wave motions, theoretical and laboratory studies predict very strong velocity variation with depth over the upper few centimeters of the water column, an observational blind spot in the real ocean. Here we present the first-ever ocean measurements of the current vector profile defined to within 1 cm of the free surface. In our illustrative example, the current magnitude averaged over the upper 1 cm of the ocean is shown to be nearly four times the average over the upper 10 m, even for mild forcing. Our findings indicate that this shear will rapidly separate pieces of marine debris which vary in size or buoyancy, making consideration of these dynamics essential to an improved understanding of the pathways along which marine plastics and oil are transported.

  20. Trapped electron effects on ICRF Current Drive Predictions in TFTR

    Science.gov (United States)

    Wright, John C.; Phillips, Cynthia K.; Bonoli, Paul T.

    1996-11-01

    Most 2D RF modeling codes use a parameterization^1 of current drive efficiencies to calculate fast wave driven currents. Because this parameterization is derived from a ray--tracing model, there are difficulties in applying it to a spectrum of waves. In addition, one cannot account for multiple resonances and coherency effects between the electrons and the waves. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient in an inhomogenous geometry coupled with a full wave code for the field polarizations. Current profiles are then calculated using the adjoint formulation^2, with the magnetic equilibrium specified consistently in both the adjoint routine and the full wave code. This approach has been implemented in the FISIC code^3. Results are benchmarked by comparing a power deposition calculation from conductivity to one from the quasilinear expression. It is shown that the two expressions agree. We quantify differences seen based upon aspect ratio and elongation. The largest discrepancies are seen in the regime of small aspect ratio, and little loss in accuracy for moderate aspect ratios ~>3. This work supported by DoE contract No. DE--AC02--76--CH03073. ^1 D. A. Ehst and C. F. F. Karney, Nucl. Fusion 31, 1933 (1991). ^2 C. F. F. Karney, Computer Physics Reports 4, 183 (1986). ^3 M. Brambilla and T. Krücken, Nucl. Fusion 28, 1813 (1988).

  1. Accurate prediction of peptide binding sites on protein surfaces.

    Directory of Open Access Journals (Sweden)

    Evangelia Petsalaki

    2009-03-01

    Full Text Available Many important protein-protein interactions are mediated by the binding of a short peptide stretch in one protein to a large globular segment in another. Recent efforts have provided hundreds of examples of new peptides binding to proteins for which a three-dimensional structure is available (either known experimentally or readily modeled but where no structure of the protein-peptide complex is known. To address this gap, we present an approach that can accurately predict peptide binding sites on protein surfaces. For peptides known to bind a particular protein, the method predicts binding sites with great accuracy, and the specificity of the approach means that it can also be used to predict whether or not a putative or predicted peptide partner will bind. We used known protein-peptide complexes to derive preferences, in the form of spatial position specific scoring matrices, which describe the binding-site environment in globular proteins for each type of amino acid in bound peptides. We then scan the surface of a putative binding protein for sites for each of the amino acids present in a peptide partner and search for combinations of high-scoring amino acid sites that satisfy constraints deduced from the peptide sequence. The method performed well in a benchmark and largely agreed with experimental data mapping binding sites for several recently discovered interactions mediated by peptides, including RG-rich proteins with SMN domains, Epstein-Barr virus LMP1 with TRADD domains, DBC1 with Sir2, and the Ago hook with Argonaute PIWI domain. The method, and associated statistics, is an excellent tool for predicting and studying binding sites for newly discovered peptides mediating critical events in biology.

  2. Methodology for prediction of rip currents using a three-dimensional numerical, coupled, wave current model

    Science.gov (United States)

    Voulgaris, George; Kumar, Nirnimesh; Warner, John C.; Leatherman, Stephen; Fletemeyer, John

    2011-01-01

    Rip current currents constitute one of the most common hazards in the nearshore that threaten the lives of the unaware public that makes recreational use of the coastal zone. Society responds to this danger through a number of measures that include: (a) the deployment of trained lifeguards; (b) public education related to the hidden hazards of the nearshore; and (c) establishment of warning systems.

  3. Predictions of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, D.B.; Baity, F.W.; Carter, M.D. [and others

    1994-12-31

    The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve these objectives requires compatibility and flexibility in the use of available heating and current drive systems--ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various roles of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The authors have addressed these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX.

  4. Predictions of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

    International Nuclear Information System (INIS)

    Batchelor, D.B.; Baity, F.W.; Carter, M.D.

    1994-01-01

    The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve these objectives requires compatibility and flexibility in the use of available heating and current drive systems--ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various roles of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The authors have addressed these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX

  5. Galeazzi fractures: Is DRUJ instability predicted by current guidelines?

    Science.gov (United States)

    Tsismenakis, Tony; Tornetta, Paul

    2016-07-01

    Clinically significant distal radioulnar joint (DRUJ) injuries can occur with radial shaft fractures. Several radiographic methods of diagnosis, such as radial shortening of >5mm or fracture line within 7.5cm from the lunate facet, have been proposed but not clinically validated. The purpose of this study was to compare radiographic measurements of radial shaft fractures associated with and without clinically significant DRUJ injury (i.e., true Galeazzi fracture-dislocation) in order to evaluate the predictive value of reported parameters of DRUJ injury. A retrospective record and radiographic review was performed of 66 consecutive skeletally mature patients with isolated radial shaft fractures from 2004 to 2014 treated at one level 1 academic trauma center. Intraoperatively determined DRUJ instability after radial shaft fixation was used as the gold standard for diagnosis of a Galeazzi fracture-dislocation. Average age was 34 years old (range: 18-90). By thirds, there were 10 proximal (15%), 27 middle (41%), and 29 distal (44%) fractures. 13 (20%) had an associated ulnar styloid fracture. 7 (11%) patients had DRUJ instability after radial fixation. Radial shortening averaged 4.4±5.2mm (-2.6-22), and 21 had shortening of >5mm. Twenty-six (39%) fractures were within 7.5cm of the wrist joint. Previous guidelines were only moderately accurate. Even greater shortening did not predict instability (3/7 patients with >10mm shortening had a true injury). Four out of 7 cases with instability had ulnar styloid fractures (p=0.02). Using a larger data set than has historically been evaluated, previously reported radiographic guidelines are only moderately accurate. The presence of an ulnar styloid fracture can be helpful. Surgeons should be aware of these associations but rely primarily on intraoperative assessment of the DRUJ after radial fixation to determine treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Prediction of water droplet evaporation on zircaloy surface

    International Nuclear Information System (INIS)

    Lee, Chi Young; In, Wang Kee

    2014-01-01

    In the present experimental study, the prediction of water droplet evaporation on a zircaloy surface was investigated using various initial droplet sizes. To the best of our knowledge, this may be the first valuable effort for understanding the details of water droplet evaporation on a zircaloy surface. The initial contact diameters of the water droplets tested ranged from 1.76 to 3.41 mm. The behavior (i.e., time-dependent droplet volume, contact angle, droplet height, and contact diameter) and mode-transition time of the water droplet evaporation were strongly influenced by the initial droplet size. Using the normalized contact angle (θ*) and contact diameter (d*), the transitions between evaporation modes were successfully expressed by a single curve, and their criteria were proposed. To predict the temporal droplet volume change and evaporation rate, the range of θ* > 0.25 and d* > 0.9, which mostly covered the whole evaporation period and the initial contact diameter remained almost constant during evaporation, was targeted. In this range, the previous contact angle functions for the evaporation model underpredicted the experimental data. A new contact angle function of a zircaloy surface was empirically proposed, which represented the present experimental data within a reasonable degree of accuracy. (author)

  7. Current status of the near surface repository in Romania

    International Nuclear Information System (INIS)

    Andrei, V.; Glodeanu, F.; Rotaru, I.

    2000-01-01

    The radioactive waste management at the Cernavoda NPP is based on collection, pretreatment and storage of all solid wastes. The disposal of operational and decommissioning wastes has been evaluated, based on the results of a research and development programme. A near surface disposal facility was selected and a siting process was implemented. The status of this project and its prospective are discussed in the paper. (author)

  8. The current status of biomarkers for predicting toxicity

    Science.gov (United States)

    Campion, Sarah; Aubrecht, Jiri; Boekelheide, Kim; Brewster, David W; Vaidya, Vishal S; Anderson, Linnea; Burt, Deborah; Dere, Edward; Hwang, Kathleen; Pacheco, Sara; Saikumar, Janani; Schomaker, Shelli; Sigman, Mark; Goodsaid, Federico

    2013-01-01

    Introduction There are significant rates of attrition in drug development. A number of compounds fail to progress past preclinical development due to limited tools that accurately monitor toxicity in preclinical studies and in the clinic. Research has focused on improving tools for the detection of organ-specific toxicity through the identification and characterization of biomarkers of toxicity. Areas covered This article reviews what we know about emerging biomarkers in toxicology, with a focus on the 2012 Northeast Society of Toxicology meeting titled ‘Translational Biomarkers in Toxicology.’ The areas covered in this meeting are summarized and include biomarkers of testicular injury and dysfunction, emerging biomarkers of kidney injury and translation of emerging biomarkers from preclinical species to human populations. The authors also provide a discussion about the biomarker qualification process and possible improvements to this process. Expert opinion There is currently a gap between the scientific work in the development and qualification of novel biomarkers for nonclinical drug safety assessment and how these biomarkers are actually used in drug safety assessment. A clear and efficient path to regulatory acceptance is needed so that breakthroughs in the biomarker toolkit for nonclinical drug safety assessment can be utilized to aid in the drug development process. PMID:23961847

  9. Predicting and managing sepsis in burn patients: current perspectives

    Directory of Open Access Journals (Sweden)

    Nunez Lopez O

    2017-08-01

    Full Text Available Omar Nunez Lopez,1,2 Janos Cambiaso-Daniel,1–3 Ludwik K Branski,1,2 William B Norbury,1,2 David N Herndon1,2,4 1Department of Surgery, University of Texas Medical Branch, 2Shriners Hospitals for Children, Galveston, TX, USA; 3Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; 4Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA Abstract: Modern burn care has led to unprecedented survival rates in burn patients whose injuries were fatal a few decades ago. Along with improved survival, new challenges have emerged in the management of burn patients. Infections top the list of the most common complication after burns, and sepsis is the leading cause of death in both adult and pediatric burn patients. The diagnosis and management of sepsis in burns is complex as a tremendous hypermetabolic response secondary to burn injury can be superimposed on systemic infection, leading to organ dysfunction. The management of a septic burn patient represents a challenging scenario that is commonly encountered by providers caring for burn patients despite preventive efforts. Here, we discuss the current perspectives in the diagnosis and treatment of sepsis and septic shock in burn patients. Keywords: burn injury, thermal injury, burn sepsis, procalcitonin, antibiotics, biomarkers, cytokines

  10. Surface Intermediate Zone of Submerged Turbulent Buoyant Jet in Current

    DEFF Research Database (Denmark)

    Chen, H. B.; Larsen, Torben

    1995-01-01

    This paper deals with the intermediate zone between the jet and plume stages of a submerged buoyant discharge from sea outfall in current. The stability criteria, plume width and height after the intermediate zone and the dilution within the intermediate region have been studied theoretically...

  11. Estimating Discharge, Depth and Bottom Friction in Sand Bed Rivers Using Surface Currents and Water Surface Elevation Observations

    Science.gov (United States)

    Simeonov, J.; Czapiga, M. J.; Holland, K. T.

    2017-12-01

    We developed an inversion model for river bathymetry estimation using measurements of surface currents, water surface elevation slope and shoreline position. The inversion scheme is based on explicit velocity-depth and velocity-slope relationships derived from the along-channel momentum balance and mass conservation. The velocity-depth relationship requires the discharge value to quantitatively relate the depth to the measured velocity field. The ratio of the discharge and the bottom friction enter as a coefficient in the velocity-slope relationship and is determined by minimizing the difference between the predicted and the measured streamwise variation of the total head. Completing the inversion requires an estimate of the bulk friction, which in the case of sand bed rivers is a strong function of the size of dune bedforms. We explored the accuracy of existing and new empirical closures that relate the bulk roughness to parameters such as the median grain size diameter, ratio of shear velocity to sediment fall velocity or the Froude number. For given roughness parameterization, the inversion solution is determined iteratively since the hydraulic roughness depends on the unknown depth. We first test the new hydraulic roughness parameterization using estimates of the Manning roughness in sand bed rivers based on field measurements. The coupled inversion and roughness model is then tested using in situ and remote sensing measurements of the Kootenai River east of Bonners Ferry, ID.

  12. Predicting 3D lip shapes using facial surface EMG.

    Directory of Open Access Journals (Sweden)

    Merijn Eskes

    Full Text Available The aim of this study is to prove that facial surface electromyography (sEMG conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and their associated motions.With a stereo camera set-up, we recorded 3D lip shapes and simultaneously performed sEMG measurements of the facial muscles, applying principal component analysis (PCA and a modified general regression neural network (GRNN to link the sEMG measurements to 3D lip shapes. To test reproducibility, we conducted our experiment on five volunteers, evaluating several sEMG features and window lengths in unipolar and bipolar configurations in search of the optimal settings for facial sEMG.The errors of the two methods were comparable. We managed to predict 3D lip shapes with a mean accuracy of 2.76 mm when using the PCA method and 2.78 mm when using modified GRNN. Whereas performance improved with shorter window lengths, feature type and configuration had little influence.

  13. Current status of surface water pollution in Punjab

    International Nuclear Information System (INIS)

    Bashir, M.T.; Ghauri, Moin-ud-Din

    2001-01-01

    Eleven years investigations (1988-99) on river Ravi revealed that U.C. canal with a capacity of 220 m/sup 3//s at the tail and Q.B. Link canal with capacity of 410 m/sup 3//s are mainly responsible for higher flows during dry season. A decreasing trend has been observed in the DO levels indicating increasing pollution. An increasing trend has been observed in BOD, SS, TDS and Indicators. Even with the discharge of pollution from U.C. canal, Hudiara Nullah and Lahore city BOD at Balkoi was unexpectedly low. Problems confronting environment engineers regarding surface water pollution control has been highlighted and their solutions has been recommended. (author)

  14. Sea surface temperature predictions using a multi-ocean analysis ensemble scheme

    Science.gov (United States)

    Zhang, Ying; Zhu, Jieshun; Li, Zhongxian; Chen, Haishan; Zeng, Gang

    2017-08-01

    This study examined the global sea surface temperature (SST) predictions by a so-called multiple-ocean analysis ensemble (MAE) initialization method which was applied in the National Centers for Environmental Prediction (NCEP) Climate Forecast System Version 2 (CFSv2). Different from most operational climate prediction practices which are initialized by a specific ocean analysis system, the MAE method is based on multiple ocean analyses. In the paper, the MAE method was first justified by analyzing the ocean temperature variability in four ocean analyses which all are/were applied for operational climate predictions either at the European Centre for Medium-range Weather Forecasts or at NCEP. It was found that these systems exhibit substantial uncertainties in estimating the ocean states, especially at the deep layers. Further, a set of MAE hindcasts was conducted based on the four ocean analyses with CFSv2, starting from each April during 1982-2007. The MAE hindcasts were verified against a subset of hindcasts from the NCEP CFS Reanalysis and Reforecast (CFSRR) Project. Comparisons suggested that MAE shows better SST predictions than CFSRR over most regions where ocean dynamics plays a vital role in SST evolutions, such as the El Niño and Atlantic Niño regions. Furthermore, significant improvements were also found in summer precipitation predictions over the equatorial eastern Pacific and Atlantic oceans, for which the local SST prediction improvements should be responsible. The prediction improvements by MAE imply a problem for most current climate predictions which are based on a specific ocean analysis system. That is, their predictions would drift towards states biased by errors inherent in their ocean initialization system, and thus have large prediction errors. In contrast, MAE arguably has an advantage by sampling such structural uncertainties, and could efficiently cancel these errors out in their predictions.

  15. Ocean Surface Current Vectors from MODIS Terra/Aqua Sea Surface Temperature Image Pairs, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Satellites that record imagery of the same sea surface area, at times separated by a few hours, can be used to estimate ocean surface velocity fields based on the...

  16. On the sources of global land surface hydrologic predictability

    Directory of Open Access Journals (Sweden)

    S. Shukla

    2013-07-01

    Full Text Available Global seasonal hydrologic prediction is crucial to mitigating the impacts of droughts and floods, especially in the developing world. Hydrologic predictability at seasonal lead times (i.e., 1–6 months comes from knowledge of initial hydrologic conditions (IHCs and seasonal climate forecast skill (FS. In this study we quantify the contributions of two primary components of IHCs – soil moisture and snow water content – and FS (of precipitation and temperature to seasonal hydrologic predictability globally on a relative basis throughout the year. We do so by conducting two model-based experiments using the variable infiltration capacity (VIC macroscale hydrology model, one based on ensemble streamflow prediction (ESP and another based on Reverse-ESP (Rev-ESP, both for a 47 yr re-forecast period (1961–2007. We compare cumulative runoff (CR, soil moisture (SM and snow water equivalent (SWE forecasts from each experiment with a VIC model-based reference data set (generated using observed atmospheric forcings and estimate the ratio of root mean square error (RMSE of both experiments for each forecast initialization date and lead time, to determine the relative contribution of IHCs and FS to the seasonal hydrologic predictability. We find that in general, the contributions of IHCs to seasonal hydrologic predictability is highest in the arid and snow-dominated climate (high latitude regions of the Northern Hemisphere during forecast periods starting on 1 January and 1 October. In mid-latitude regions, such as the Western US, the influence of IHCs is greatest during the forecast period starting on 1 April. In the arid and warm temperate dry winter regions of the Southern Hemisphere, the IHCs dominate during forecast periods starting on 1 April and 1 July. In equatorial humid and monsoonal climate regions, the contribution of FS is generally higher than IHCs through most of the year. Based on our findings, we argue that despite the limited FS

  17. Modelling of electrochemical reactors with bio polar electrodes. Prediction of the current distributions

    International Nuclear Information System (INIS)

    HenquIn, E. R; Bisang, J. M

    2005-01-01

    A simplified mathematical model to calculate the current distributions in bipolar electrochemical reactors is proposed.The current distributions are deduced from a combination of the voltage balance in the reactor with a voltage balance including the electrolyte inlet and outlet.Thus, equations to predict the effect of geometric and operational variables on the current distributions at the electrodes are reported.The parameters acting upon the current distributions were lumped into two dimensionless variables and their effects on the current distributions are discussed.The primary current distributions are obtained as a limiting case.Comparisons between calculated and experimental primary current distributions are reported

  18. A robust empirical seasonal prediction of winter NAO and surface climate.

    Science.gov (United States)

    Wang, L; Ting, M; Kushner, P J

    2017-03-21

    A key determinant of winter weather and climate in Europe and North America is the North Atlantic Oscillation (NAO), the dominant mode of atmospheric variability in the Atlantic domain. Skilful seasonal forecasting of the surface climate in both Europe and North America is reflected largely in how accurately models can predict the NAO. Most dynamical models, however, have limited skill in seasonal forecasts of the winter NAO. A new empirical model is proposed for the seasonal forecast of the winter NAO that exhibits higher skill than current dynamical models. The empirical model provides robust and skilful prediction of the December-January-February (DJF) mean NAO index using a multiple linear regression (MLR) technique with autumn conditions of sea-ice concentration, stratospheric circulation, and sea-surface temperature. The predictability is, for the most part, derived from the relatively long persistence of sea ice in the autumn. The lower stratospheric circulation and sea-surface temperature appear to play more indirect roles through a series of feedbacks among systems driving NAO evolution. This MLR model also provides skilful seasonal outlooks of winter surface temperature and precipitation over many regions of Eurasia and eastern North America.

  19. Predicted transport of pyrethroid insecticides from an urban landscape to surface water.

    Science.gov (United States)

    Jorgenson, Brant; Fleishman, Erica; Macneale, Kate H; Schlenk, Daniel; Scholz, Nathaniel L; Spromberg, Julann A; Werner, Inge; Weston, Donald P; Xiao, Qingfu; Young, Thomas M; Zhang, Minghua

    2013-11-01

    The authors developed a simple screening-level model of exposure of aquatic species to pyrethroid insecticides for the lower American River watershed (California, USA). The model incorporated both empirically derived washoff functions based on existing, small-scale precipitation simulations and empirical data on pyrethroid insecticide use and watershed properties for Sacramento County, California, USA. The authors calibrated the model to in-stream monitoring data and used it to predict daily river pyrethroid concentration from 1995 through 2010. The model predicted a marked increase in pyrethroid toxic units starting in 2000, coincident with an observed watershed-wide increase in pyrethroid use. After 2000, approximately 70% of the predicted total toxic unit exposure in the watershed was associated with the pyrethroids bifenthrin and cyfluthrin. Pyrethroid applications for aboveground structural pest control on the basis of suspension concentrate categorized product formulations accounted for greater than 97% of the predicted total toxic unit exposure. Projected application of mitigation strategies, such as curtailment of structural perimeter band and barrier treatments as recently adopted by the California Department of Pesticide Regulation, reduced predicted total toxic unit exposure by 84%. The model also predicted that similar reductions in surface-water concentrations of pyrethroids could be achieved through a switch from suspension concentrate-categorized products to emulsifiable concentrate-categorized products without restrictions on current-use practice. Even with these mitigation actions, the predicted concentration of some pyrethroids would continue to exceed chronic aquatic life criteria. © 2013 SETAC.

  20. Validation of HF Radar ocean surface currents in the Ibiza Channel using lagrangian drifters, moored current meter and underwater gliders

    Science.gov (United States)

    Lana, Arancha; Fernández, Vicente; Orfila, Alejandro; Troupin, Charles; Tintoré, Joaquín

    2015-04-01

    SOCIB High Frequency (HF) radar is one component of a multi-platform system located in the Balearic Islands and made up of Lagrangian platforms (profilers and drifting buoys), fixed stations (sea-level, weather, mooring and coastal), beach monitoring (camera), gliders, a research vessel as well as an ocean forecast system (waves and hydrodynamics). The HF radar system overlooks the Ibiza Channel, known as a 'choke point" where Atlantic and Mediterranean water masses interact and where meridional exchanges of water mass properties between the Balearic and the Algerian sub-basins take place. In order to determine the reliability of surface velocity measurements in this area, a quality assessment of the HF Radar is essential. We present the results of several validation experiments performed in the Ibiza Channel in 2013 and 2014. Of particular interest is an experiment started in September 2014 when a set of 13 surface drifters with different shapes and drogue lengths were released in the area covered by the HF radar. The drifter trajectories can be examined following the SOCIB Deployment Application (DAPP): http://apps.socib.es/dapp. Additionally, a 1-year long time series of surface currents obtained from a moored surface current-meter located in the Ibiza Channel, inside the area covered by the HF radar, was also used as a useful complementary validation exercise. Direct comparison between both radial surface currents from each radar station and total derived velocities against drifters and moored current meter velocities provides an assessment of the HF radar data quality at different temporal periods and geographical areas. Statistics from these comparisons give good correlation and low root-mean-square deviation. The results will be discussed for different months, geographical areas and types of surface drifters and wind exposure. Moreover, autonomous underwater glider constitutes an additional source of information for the validation of the observed velocity

  1. Prediction of Tidal Elevations and Barotropic Currents in the Gulf of Bone

    Science.gov (United States)

    Purnamasari, Rika; Ribal, Agustinus; Kusuma, Jeffry

    2018-03-01

    Tidal elevation and barotropic current predictions in the gulf of Bone have been carried out in this work based on a two-dimensional, depth-integrated Advanced Circulation (ADCIRC-2DDI) model for 2017. Eight tidal constituents which were obtained from FES2012 have been imposed along the open boundary conditions. However, even using these very high-resolution tidal constituents, the discrepancy between the model and the data from tide gauge is still very high. In order to overcome such issues, Green’s function approach has been applied which reduced the root-mean-square error (RMSE) significantly. Two different starting times are used for predictions, namely from 2015 and 2016. After improving the open boundary conditions, RMSE between observation and model decreased significantly. In fact, RMSEs for 2015 and 2016 decreased 75.30% and 88.65%, respectively. Furthermore, the prediction for tidal elevations as well as tidal current, which is barotropic current, is carried out. This prediction was compared with the prediction conducted by Geospatial Information Agency (GIA) of Indonesia and we found that our prediction is much better than one carried out by GIA. Finally, since there is no tidal current observation available in this area, we assume that, when tidal elevations have been fixed, then the tidal current will approach the actual current velocity.

  2. Improvement of a land surface model for accurate prediction of surface energy and water balances

    International Nuclear Information System (INIS)

    Katata, Genki

    2009-02-01

    In order to predict energy and water balances between the biosphere and atmosphere accurately, sophisticated schemes to calculate evaporation and adsorption processes in the soil and cloud (fog) water deposition on vegetation were implemented in the one-dimensional atmosphere-soil-vegetation model including CO 2 exchange process (SOLVEG2). Performance tests in arid areas showed that the above schemes have a significant effect on surface energy and water balances. The framework of the above schemes incorporated in the SOLVEG2 and instruction for running the model are documented. With further modifications of the model to implement the carbon exchanges between the vegetation and soil, deposition processes of materials on the land surface, vegetation stress-growth-dynamics etc., the model is suited to evaluate an effect of environmental loads to ecosystems by atmospheric pollutants and radioactive substances under climate changes such as global warming and drought. (author)

  3. Predicting high-current disruptions on NSTX with stacked regression trees

    Science.gov (United States)

    Barbour, Nathaniel; Kleijwegt, Kornee; Lupin-Jimenez, Leonard; Kolemen, Egemen

    2017-10-01

    Disruption mitigation and avoidance are critical objectives for the successful operation of ITER. Of particular interest is the prospect of predicting disruptions during its first high-plasma-current experiments, when only low-current data will be available. Toward achieving those objectives, data from an initial sample of 1,000 shots are separated into two groups by plasma current. Four regression tree algorithms are then used as disruption predictors: AdaBoost, random forests, extremely randomized trees, and bootstrap aggregating (``bagging''). Each algorithm is trained using data from low-current shots and used to predict disruptions in the sample of high-current shots. To improve prediction accuracy, multiple methods of scaling the input signal data are examined. The creation of a meta-estimator from the predictions of the four regression tree algorithms is explored. A future extension is to predict high-current disruptions on other devices using a meta-estimator trained with low-current data from NSTX and NSTX-U. Supported by the US DOE Contract No. DE-AC02-09CH11466.

  4. Prediction and Optimization of Residual Stresses on Machined Surface and Sub-Surface in MQL Turning

    Science.gov (United States)

    Ji, Xia; Zou, Pan; Li, Beizhi; Rajora, Manik; Shao, Yamin; Liang, Steven Y.

    Residual stress in the machined surface and subsurface is affected by materials, machining conditions, and tool geometry and can affect the component life and service quality significantly. Empirical or numerical experiments are commonly used for determining residual stresses but these are very expensive. There has been an increase in the utilization of minimum quantity lubrication (MQL) in recent years in order to reduce the cost and tool/part handling efforts, while its effect on machined part residual stress, although important, has not been explored. This paper presents a hybrid neural network that is trained using Simulated Annealing (SA) and Levenberg-Marquardt Algorithm (LM) in order to predict the values of residual stresses in cutting and radial direction on the surface and within the work piece after the MQL face turning process. Once the ANN has successfully been trained, an optimization procedure, using Genetic Algorithm (GA), is applied in order to find the best cutting conditions in order to minimize the surface tensile residual stresses and maximize the compressive residual stresses within the work piece. The optimization results show that the usage of MQL decreases the surface tensile residual stresses and increases the compressive residual stresses within the work piece.

  5. Artificial neural network accurately predicts hepatitis B surface antigen seroclearance.

    Directory of Open Access Journals (Sweden)

    Ming-Hua Zheng

    Full Text Available BACKGROUND & AIMS: Hepatitis B surface antigen (HBsAg seroclearance and seroconversion are regarded as favorable outcomes of chronic hepatitis B (CHB. This study aimed to develop artificial neural networks (ANNs that could accurately predict HBsAg seroclearance or seroconversion on the basis of available serum variables. METHODS: Data from 203 untreated, HBeAg-negative CHB patients with spontaneous HBsAg seroclearance (63 with HBsAg seroconversion, and 203 age- and sex-matched HBeAg-negative controls were analyzed. ANNs and logistic regression models (LRMs were built and tested according to HBsAg seroclearance and seroconversion. Predictive accuracy was assessed with area under the receiver operating characteristic curve (AUROC. RESULTS: Serum quantitative HBsAg (qHBsAg and HBV DNA levels, qHBsAg and HBV DNA reduction were related to HBsAg seroclearance (P<0.001 and were used for ANN/LRM-HBsAg seroclearance building, whereas, qHBsAg reduction was not associated with ANN-HBsAg seroconversion (P = 0.197 and LRM-HBsAg seroconversion was solely based on qHBsAg (P = 0.01. For HBsAg seroclearance, AUROCs of ANN were 0.96, 0.93 and 0.95 for the training, testing and genotype B subgroups respectively. They were significantly higher than those of LRM, qHBsAg and HBV DNA (all P<0.05. Although the performance of ANN-HBsAg seroconversion (AUROC 0.757 was inferior to that for HBsAg seroclearance, it tended to be better than those of LRM, qHBsAg and HBV DNA. CONCLUSIONS: ANN identifies spontaneous HBsAg seroclearance in HBeAg-negative CHB patients with better accuracy, on the basis of easily available serum data. More useful predictors for HBsAg seroconversion are still needed to be explored in the future.

  6. Smooth Surfaces: A review of current and planned smooth surface technologies for fouling resistance in boiler

    Energy Technology Data Exchange (ETDEWEB)

    Corkery, Robert; Baefver, Linda; Davidsson, Kent; Feiler, Adam

    2012-02-15

    Here we have described the basics of boilers, fuels, combustion, flue gas composition and mechanisms of deposition. We have reviewed coating technologies for boiler tubes, including their materials compositions, nano structures and performances. The surface forces in boilers, in particular those relevant to formation of unwanted deposits in boilers have also been reviewed, and some comparative calculations have been included to indicate the procedures needed for further study. Finally practical recommendations on the important considerations in minimizing deposition on boiler surfaces are made

  7. High performance predictive current control of a three phase VSI: An ...

    Indian Academy of Sciences (India)

    The effect of weighting factor on the switching frequency minimization and the current tracking error with delay compensation for the two level voltage source inverter (VSI) are investigated in this paper. The outcomes of the predictive current control using an optimized weighting factor which is calculated using branch and ...

  8. Mortality risk prediction models for coronary artery bypass graft surgery: current scenario and future direction.

    Science.gov (United States)

    Karim, Mohammed N; Reid, Christopher M; Cochrane, Andrew; Tran, Lavinia; Alramadan, Mohammed; Hossain, Mohammed N; Billah, Baki

    2017-12-01

    Many risk prediction models are currently in use for predicting short-term mortality following coronary artery bypass graft (CABG) surgery. This review critically appraised the methods that were used for developing these models to assess their applicability in current practice setting as well as for the necessity of up-gradation. Medline via Ovid was searched for articles published between 1946 and 2016 and EMBASE via Ovid between 1974 and 2016 to identify risk prediction models for CABG. Article selection and data extraction was conducted using the CHARMS checklist for review of prediction model studies. Association between model development methods and model's discrimination was assessed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-test. A total of 53 risk prediction models for short-term mortality following CABG were identified. The review found a wide variation in development methodology of risk prediction models in the field. Ambiguous predictor and outcome definition, sub-optimum sample size, inappropriate handling of missing data and inefficient predictor selection technique are major issues identified in the review. Quantitative synthesis in the review showed "missing value imputation" and "adopting machine learning algorithms" may result in better discrimination power of the models. There are aspects in current risk modeling, where there is room for improvement to reflect current clinical practice. Future risk modelling needs to adopt a standardized approach to defining both outcome and predictor variables, rational treatment of missing data and robust statistical techniques to enhance performance of the mortality risk prediction.

  9. Response Predicting LTCC Firing Shrinkage: A Response Surface Analysis Study

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, Michael; Barner, Gregg; Lopez, Cristie; Duncan, Brent; Zawicki, Larry

    2009-02-25

    The Low Temperature Cofired Ceramic (LTCC) technology is used in a variety of applications including military/space electronics, wireless communication, MEMS, medical and automotive electronics. The use of LTCC is growing due to the low cost of investment, short development time, good electrical and mechanical properties, high reliability, and flexibility in design integration (3 dimensional (3D) microstructures with cavities are possible)). The dimensional accuracy of the resulting x/y shrinkage of LTCC substrates is responsible for component assembly problems with the tolerance effect that increases in relation to the substrate size. Response Surface Analysis was used to predict product shrinkage based on specific process inputs (metal loading, layer count, lamination pressure, and tape thickness) with the ultimate goal to optimize manufacturing outputs (NC files, stencils, and screens) in achieving the final product design the first time. Three (3) regression models were developed for the DuPont 951 tape system with DuPont 5734 gold metallization based on green tape thickness.

  10. Research of the Ion Current Density Influence on the Glass-Ceramics Surface Defects Forming under Ion-Beam Processing

    Directory of Open Access Journals (Sweden)

    V. G. Pozdnyakov

    2015-01-01

    Full Text Available Development of modern optics is primarily determined by manufacturing accuracy of the working surfaces of optical parts. Therefore, at the last stage of manufacturing optical parts the ion-beam treatment is applied. This method uses spraying the high-energy ions of heavy gases on the surface of a solid body. After an intense ion treatment there are microscopic defects, resembling chips, on the surface of polycrystalline glass. The aim of this work is to study distribution of the surface density of defects by sizes, depending on the density of ion current.Accelerator with an anode layer and a focused ion beam was used as an ion source. The accelerator worked on argon and created ion beam with Gaussian distribution of current density along the radius. The excess positive charge of the ion beam was compensated owing to ionization of residual gas. To eliminate the influence of slow ions with peripheral regions of the ion beam, the etching was performed through a circular aperture with a diameter of 40 mm.Surface treatment of the sample was carried out at the discharge voltage of 3800 V and current of 50 mA for 30 min. The maximum ion current density on the sample surface was 20.2 A/m2 and a power density was of 5.4·104 W/m2 .Distribution of defects by size was measured in three areas of the treated surface corresponding to different densities of ion current, namely: 20.2 A/m2 , 11.3A/m2 , and 3.4 A/m2 . Their number per area unit defines a density of defects.The results show that with increasing ion current density the density of defects on the surface of polycrystalline glass decreases. Thus a view of distribution function of defect density according to size is changed: density of small defects is reduced, and density of large ones increases. Also with increasing ion current density is observed an increase in the size of defects: a 6 times increase of the average size of defects results in 1.6 times increasing ion current density.These data will

  11. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Directory of Open Access Journals (Sweden)

    Thangam Chinnadurai

    2016-12-01

    Full Text Available This study focuses on investigating the effects of process parameters, namely, Peak current (Ip, Pulse on time (Ton, Pulse off time (Toff, Water pressure (Wp, Wire feed rate (Wf, Wire tension (Wt, Servo voltage (Sv and Servo feed setting (Sfs, on the Material Removal Rate (MRR and Surface Roughness (SR for Wire electrical discharge machining (Wire-EDM of nickel using Taguchi method. Response Surface Methodology (RSM is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used.

  12. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Chinnadurai, T.; Vendan, S.A.

    2016-07-01

    This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used. (Author)

  13. Operational surface currents derived from satellite altimeters and scatterometers; Pilot Study for the Tropical Pacific

    Science.gov (United States)

    Lagerloef, G.

    1 and diagnose model errors. Another immediate application of these data relates to fisheries management and ma- rine wildlife research in the region. Movements of several species of sea turtle in the tropical region are being tracked by satellite with System Argos. Results show that some turtle tracks follow meandering portions of the North Equatorial Current and North Equatorial Counter Current. The surface current data allow researchers to exam- ine the oceanography of the habitat these turtles are using, for example, and evaluate to what extent they are using the equatorial currents and regions of surface convergence. Findings indicate that different species/stocks use different habitats. Some forage at or near the surface at convergences and others forage sub-surface away from currents (Polovina et al., 2002). References: Bonjean, F. and G.S.E. Lagerloef, 2002: Diagnostic model and analysis of the surface currents in the Tropical Pacific Ocean, J. Phys. Oceanogr., In press. Lagerloef,G.S.E., G.Mitchum, R.Lukas and P.Niiler, 1999: Tropical Pacific near sur- face currents estimated from altimeter, wind and drifter data, J. Geophys. Res., 104, 23,313-23,326. Polovina, J. J., G. H. Balazs, E. A Howell, D. M. Parker, M. P. Seki, and P. H. Dutton, 2002. Forage and migration habitat of loggerhead (Caretta caretta) and olive ridley (Lepidochelys olivacea) sea turtles in the central North Pacific Ocean. Fish. Oceanogr., In Review.

  14. Predicting Near-Surface Meteorological Variations over Different Vegetation Types

    NARCIS (Netherlands)

    Hutjes, R.W.A.; Klaassen, W.; Kruijt, B.; Veen, A.W.L.

    1991-01-01

    Meteorological conditions close to a surface are strongly influenced by the properties of the surface itself. As a result, input data for models calculating evaporation of surfaces differing from the measurement site need to be transformed. A transformation scheme proposed previously is tested on

  15. Where the wild things are: Predicting hotspots of seabird aggregations in the California Current System

    Science.gov (United States)

    Nur, N.; Jahncke, J.; Herzog, M.P.; Howar, J.; Hyrenbach, K.D.; Zamon, J.E.; Ainley, D.G.; Wiens, J.A.; Morgan, K.; Balance, L.T.; Stralberg, D.

    2011-01-01

    Marine Protected Areas (MPAs) provide an important tool for conservation of marine ecosystems. To be most effective, these areas should be strategically located in a manner that supports ecosystem function. To inform marine spatial planning and support strategic establishment of MPAs within the California Current System, we identified areas predicted to support multispecies aggregations of seabirds ("hotspot????). We developed habitat-association models for 16 species using information from at-sea observations collected over an 11-year period (1997-2008), bathymetric data, and remotely sensed oceanographic data for an area from north of Vancouver Island, Canada, to the USA/Mexico border and seaward 600 km from the coast. This approach enabled us to predict distribution and abundance of seabirds even in areas of few or no surveys. We developed single-species predictive models using a machine-learning algorithm: bagged decision trees. Single-species predictions were then combined to identify potential hotspots of seabird aggregation, using three criteria: (1) overall abundance among species, (2) importance of specific areas ("core area????) to individual species, and (3) predicted persistence of hotspots across years. Model predictions were applied to the entire California Current for four seasons (represented by February, May, July, and October) in each of 11 years. Overall, bathymetric variables were often important predictive variables, whereas oceanographic variables derived from remotely sensed data were generally less important. Predicted hotspots often aligned with currently protected areas (e.g., National Marine Sanctuaries), but we also identified potential hotspots in Northern California/Southern Oregon (from Cape Mendocino to Heceta Bank), Southern California (adjacent to the Channel Islands), and adjacent to Vancouver Island, British Columbia, that are not currently included in protected areas. Prioritization and identification of multispecies hotspots

  16. Predicting infant cortical surface development using a 4D varifold-based learning framework and local topography-based shape morphing.

    Science.gov (United States)

    Rekik, Islem; Li, Gang; Lin, Weili; Shen, Dinggang

    2016-02-01

    Longitudinal neuroimaging analysis methods have remarkably advanced our understanding of early postnatal brain development. However, learning predictive models to trace forth the evolution trajectories of both normal and abnormal cortical shapes remains broadly absent. To fill this critical gap, we pioneered the first prediction model for longitudinal developing cortical surfaces in infants using a spatiotemporal current-based learning framework solely from the baseline cortical surface. In this paper, we detail this prediction model and even further improve its performance by introducing two key variants. First, we use the varifold metric to overcome the limitations of the current metric for surface registration that was used in our preliminary study. We also extend the conventional varifold-based surface registration model for pairwise registration to a spatiotemporal surface regression model. Second, we propose a morphing process of the baseline surface using its topographic attributes such as normal direction and principal curvature sign. Specifically, our method learns from longitudinal data both the geometric (vertices positions) and dynamic (temporal evolution trajectories) features of the infant cortical surface, comprising a training stage and a prediction stage. In the training stage, we use the proposed varifold-based shape regression model to estimate geodesic cortical shape evolution trajectories for each training subject. We then build an empirical mean spatiotemporal surface atlas. In the prediction stage, given an infant, we select the best learnt features from training subjects to simultaneously predict the cortical surface shapes at all later timepoints, based on similarity metrics between this baseline surface and the learnt baseline population average surface atlas. We used a leave-one-out cross validation method to predict the inner cortical surface shape at 3, 6, 9 and 12 months of age from the baseline cortical surface shape at birth. Our

  17. Observation and modeling of tide- and wind-induced surface currents in Galway Bay

    Directory of Open Access Journals (Sweden)

    Lei Ren

    2015-10-01

    Full Text Available A high-frequency radar system has been deployed in Galway Bay, a semi-enclosed bay on the west coast of Ireland. The system provides surface currents with fine spatial resolution every hour. Prior to its use for model validation, the accuracy of the radar data was verified through comparison with measurements from acoustic Doppler current profilers (ADCPs and a good correlation between time series of surface current speeds and directions obtained from radar data and ADCP data. Since Galway Bay is located on the coast of the Atlantic Ocean, it is subject to relatively windy conditions, and surface currents are therefore strongly wind-driven. With a view to assimilating the radar data for forecasting purposes, a three-dimensional numerical model of Galway Bay, the Environmental Fluid Dynamics Code (EFDC, was developed based on a terrain-following vertical (sigma coordinate system. This study shows that the performance and accuracy of the numerical model, particularly with regard to tide- and wind-induced surface currents, are sensitive to the vertical layer structure. Results of five models with different layer structures are presented and compared with radar measurements. A variable vertical structure with thin layers at the bottom and the surface and thicker layers in the middle of the water column was found to be the optimal layer structure for reproduction of tide- and wind-induced surface currents. This structure ensures that wind shear can properly propagate from the surface layer to the sub-surface layers, thereby ensuring that wind forcing is not overdamped by tidal forcing. The vertical layer structure affects not only the velocities at the surface layer but also the velocities further down in the water column.

  18. Observation and modeling of tide- and wind-induced surface currents in Galway Bay

    Directory of Open Access Journals (Sweden)

    Lei REN

    2015-10-01

    Full Text Available A high-frequency radar system has been deployed in Galway Bay, a semi-enclosed bay on the west coast of Ireland. The system provides surface currents with fine spatial resolution every hour. Prior to its use for model validation, the accuracy of the radar data was verified through comparison with measurements from acoustic Doppler current profilers (ADCPs and a good correlation between time series of surface current speeds and directions obtained from radar data and ADCP data. Since Galway Bay is located on the coast of the Atlantic Ocean, it is subject to relatively windy conditions, and surface currents are therefore strongly wind-driven. With a view to assimilating the radar data for forecasting purposes, a three-dimensional numerical model of Galway Bay, the Environmental Fluid Dynamics Code (EFDC, was developed based on a terrain-following vertical (sigma coordinate system. This study shows that the performance and accuracy of the numerical model, particularly with regard to tide- and wind-induced surface currents, are sensitive to the vertical layer structure. Results of five models using different layer structures are presented and compared with radar measurements. A variable vertical structure with thin layers at the bottom and the surface and thicker layers in the middle of the water column was found to be the optimal layer structure for reproduction of tide- and wind-induced surface currents. This structure ensures that wind shear can properly propagate from the surface layer to the sub-surface layers, thereby ensuring that wind forcing is not overdamped by tidal forcing. The vertical layer structure affects not only the velocities at the surface layer but also the velocities further down in the water column.

  19. Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices

    Science.gov (United States)

    Funk, C.; Hoell, A.; Shukla, S.; Bladé, I.; Liebmann, B.; Roberts, J. B.; Robertson, F. R.; Husak, G.

    2014-12-01

    In eastern East Africa (the southern Ethiopia, eastern Kenya and southern Somalia region), poor boreal spring (long wet season) rains in 1999, 2000, 2004, 2007, 2008, 2009, and 2011 contributed to severe food insecurity and high levels of malnutrition. Predicting rainfall deficits in this region on seasonal and decadal time frames can help decision makers implement disaster risk reduction measures while guiding climate-smart adaptation and agricultural development. Building on recent research that links more frequent East African droughts to a stronger Walker circulation, resulting from warming in the Indo-Pacific warm pool and an increased east-to-west sea surface temperature (SST) gradient in the western Pacific, we show that the two dominant modes of East African boreal spring rainfall variability are tied to SST fluctuations in the western central Pacific and central Indian Ocean, respectively. Variations in these two rainfall modes can thus be predicted using two SST indices - the western Pacific gradient (WPG) and central Indian Ocean index (CIO), with our statistical forecasts exhibiting reasonable cross-validated skill (rcv ≈ 0.6). In contrast, the current generation of coupled forecast models show no skill during the long rains. Our SST indices also appear to capture most of the major recent drought events such as 2000, 2009 and 2011. Predictions based on these simple indices can be used to support regional forecasting efforts and land surface data assimilations to help inform early warning and guide climate outlooks.

  20. Predictive current control with instantaneous reactive power minimization for a four-leg indirect matrix converter

    OpenAIRE

    Garcia, Cristian F.; Rivera, Marco E.; Rodriguez, Jose R.; Wheeler, Patrick; Pena, Ruben S.

    2017-01-01

    This paper presents the experimental valida¬tion of a predictive current control strategy with minimiza¬tion of the instantaneous reactive input power for a Four-Leg Indirect Matrix Converter (4Leg-IMC). The topology includes an input matrix converter stage, which provides the dc voltage for a four-leg voltage source converter (VSC) output stage. The VSC’s fourth leg provides a path for the zero sequence load current. The control technique is based on a finite control set model predictive con...

  1. Predictive Current Control of Grid-tied Cascade H-bridge Inverter

    OpenAIRE

    Pástor, Marek; Dudrik, Jaroslav

    2013-01-01

    This paper presents a grid-tied cascade H-bridge inverter with predictive current control technique. The proposed 15-level cascade inverter consists of three H-bridge inverters with separated DC sources. At the output of the cascade inverter an L filter is used as a grid filter. The cascade inverter is controlled by the mean of RT-Lab. The predictive current regulator and one-phase synchronous reference frame PLL are designed with help of Rapid Control Prototyping. The proposed control method...

  2. Improvement of Surface Temperature Prediction Using SVR with MOGREPS Data for Short and Medium range over South Korea

    Science.gov (United States)

    Lim, S. J.; Choi, R. K.; Ahn, K. D.; Ha, J. C.; Cho, C. H.

    2014-12-01

    As the Korea Meteorology Administration (KMA) has operated Met Office Global and Regional Ensemble Prediction System (MOGREPS) with introduction of Unified Model (UM), many attempts have been made to improve predictability in temperature forecast in last years. In this study, post-processing method of MOGREPS for surface temperature prediction is developed with machine learning over 52 locations in South Korea. Past 60-day lag time was used as a training phase of Support Vector Regression (SVR) method for surface temperature forecast model. The selected inputs for SVR are followings: date and surface temperatures from Numerical Weather prediction (NWP), such as GDAPS, individual 24 ensemble members, mean and median of ensemble members for every 3hours for 12 days.To verify the reliability of SVR-based ensemble prediction (SVR-EP), 93 days are used (from March 1 to May 31, 2014). The result yielded improvement of SVR-EP by RMSE value of 16 % throughout entire prediction period against conventional ensemble prediction (EP). In particular, short range predictability of SVR-EP resulted in 18.7% better RMSE for 1~3 day forecast. The mean temperature bias between SVR-EP and EP at all test locations showed around 0.36°C and 1.36°C, respectively. SVR-EP is currently extending for more vigorous sensitivity test, such as increasing training phase and optimizing machine learning model.

  3. Effect of the surface film electric resistance on eddy current detectability of surface cracks in Alloy 600 tubes

    International Nuclear Information System (INIS)

    Saario, T.; Paine, J.P.N.

    1995-01-01

    The most widely used technique for NDE of steam generator tubing is eddy current. This technique can reliably detect cracks grown in sodium hydroxide environment only at depths greater than 50% through wall. However, cracking caused by thiosulphate solutions have been detected and sized at shallower depths. The disparity has been proposed to be caused by the different electric resistance of the crack wall surface films and corrosion products in the cracks formed in different environments. This work was undertaken to clarify the role of surface film electric resistance on the disparity found in eddy current detectability of surface cracks in alloy 600 tubes. The proposed model explaining the above mentioned disparity is the following. The detectability of tightly closed cracks by the eddy current technique depends on the electric resistance of the surface films of the crack walls. The nature and resistance of the films which form on the crack walls during operation depends on the composition of the solution inside the crack and close to the crack location. During cooling down of the steam generator, because of contraction and loss of internal pressurization, the cracks are rather tightly closed so that exchange of electrolyte and thus changes in the film properties become difficult. As a result, the surface condition prevailing at high temperature is preserved. If the environment is such that the films formed on the crack walls under operating conditions have low electric resistance, eddy current technique will fail to indicate these cracks or will underestimate the size of these cracks. However, if the electric resistance of the films is high, a tightly closed crack will resemble an open crack and will be easily indicated and correctly sized by eddy current technique

  4. Increased critical current and improved magnetic field response of BSCCO material by surface diffusion of silver

    International Nuclear Information System (INIS)

    Negm, Y.Z.; Zimmerman, G.O.; Powers, R.E.; Eckhardt, K.A.

    1994-01-01

    The authors have developed a procedure of increasing the critical current of BSCCO ceramic superconducting material, the value of the critical current is increased by 30%. Moreover the degradation of the critical current with the applied magnetic field had been decreased. The procedure consists of applying a thin layer of silver to the surface of the conductor. The details of the procedure and the improved performance are discussed. This procedure has great significance for any future application of HTSC materials where high current carrying capacity is necessary. It will therefore be important in the application of HTSC materials to SSC high current leads

  5. Disturbance estimator based predictive current control of grid-connected inverters

    OpenAIRE

    Al-Khafaji, Ahmed Samawi Ghthwan

    2013-01-01

    ABSTRACT: The work presented in my thesis considers one of the modern discrete-time control approaches based on digital signal processing methods, that have been developed to improve the performance control of grid-connected three-phase inverters. Disturbance estimator based predictive current control of grid-connected inverters is proposed. For inverter modeling with respect to the design of current controllers, we choose the d-q synchronous reference frame to make it easier to understand an...

  6. Surface potential effects in low-energy current image diffraction patterns observed on the Al(001) surface

    International Nuclear Information System (INIS)

    Fine structure observed in high-resolution low-energy electron diffraction (LEED) measurements near the energy threshold for emergence of new beams has been attributed to surface barrier effects. Recently, the surface barrier has been suggested as the source of the fine structure observed in current image diffraction (CID) patterns obtained by rastering the primary beam across an Al(001) crystal surface at a constant energy. This suggestion was based on kinematic arguments which correlated the emergence angle for a new electron beam with the observed structure in the CID pattern. In this work, the angular dependence of the elastic component of the total crystal reflectivity is calculated at constant energy. The calculations are based on full dynamical theories such as used in LEED but incorporating different surface barrier models to account for the saturating image potential. The results are compared with the experimental CID results

  7. Mechanistic variables can enhance predictive models of endotherm distributions: The American pika under current, past, and future climates

    Science.gov (United States)

    Mathewson, Paul; Moyer-Horner, Lucas; Beever, Erik; Briscoe, Natalie; Kearney, Michael T.; Yahn, Jeremiah; Porter, Warren P.

    2017-01-01

    How climate constrains species’ distributions through time and space is an important question in the context of conservation planning for climate change. Despite increasing awareness of the need to incorporate mechanism into species distribution models (SDMs), mechanistic modeling of endotherm distributions remains limited in this literature. Using the American pika (Ochotona princeps) as an example, we present a framework whereby mechanism can be incorporated into endotherm SDMs. Pika distribution has repeatedly been found to be constrained by warm temperatures, so we used Niche Mapper, a mechanistic heat-balance model, to convert macroclimate data to pika-specific surface activity time in summer across the western United States. We then explored the difference between using a macroclimate predictor (summer temperature) and using a mechanistic predictor (predicted surface activity time) in SDMs. Both approaches accurately predicted pika presences in current and past climate regimes. However, the activity models predicted 8–19% less habitat loss in response to annual temperature increases of ~3–5 °C predicted in the region by 2070, suggesting that pikas may be able to buffer some climate change effects through behavioral thermoregulation that can be captured by mechanistic modeling. Incorporating mechanism added value to the modeling by providing increased confidence in areas where different modeling approaches agreed and providing a range of outcomes in areas of disagreement. It also provided a more proximate variable relating animal distribution to climate, allowing investigations into how unique habitat characteristics and intraspecific phenotypic variation may allow pikas to exist in areas outside those predicted by generic SDMs. Only a small number of easily obtainable data are required to parameterize this mechanistic model for any endotherm, and its use can improve SDM predictions by explicitly modeling a widely applicable direct physiological effect

  8. The Current and Future Use of Ridge Regression for Prediction in Quantitative Genetics

    Directory of Open Access Journals (Sweden)

    Ronald de Vlaming

    2015-01-01

    Full Text Available In recent years, there has been a considerable amount of research on the use of regularization methods for inference and prediction in quantitative genetics. Such research mostly focuses on selection of markers and shrinkage of their effects. In this review paper, the use of ridge regression for prediction in quantitative genetics using single-nucleotide polymorphism data is discussed. In particular, we consider (i the theoretical foundations of ridge regression, (ii its link to commonly used methods in animal breeding, (iii the computational feasibility, and (iv the scope for constructing prediction models with nonlinear effects (e.g., dominance and epistasis. Based on a simulation study we gauge the current and future potential of ridge regression for prediction of human traits using genome-wide SNP data. We conclude that, for outcomes with a relatively simple genetic architecture, given current sample sizes in most cohorts (i.e., N<10,000 the predictive accuracy of ridge regression is slightly higher than the classical genome-wide association study approach of repeated simple regression (i.e., one regression per SNP. However, both capture only a small proportion of the heritability. Nevertheless, we find evidence that for large-scale initiatives, such as biobanks, sample sizes can be achieved where ridge regression compared to the classical approach improves predictive accuracy substantially.

  9. Active power filter for medium voltage networks with predictive current control

    Energy Technology Data Exchange (ETDEWEB)

    Verne, Santiago A.; Valla, Maria I. [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI), Facultad de Ingenieria, Universidad Nacional de La Plata and CONICET, La Plata (Argentina)

    2010-12-15

    A transformer less Shunt Active Power Filter (SAPF) for medium voltage distribution networks based on Multilevel Diode Clamped Inverter is presented in this paper. Converter current control is based on a Model Predictive strategy, which gives very fast current response. Also, the algorithm includes voltage balancing capability which is essential for proper converter operation. The presented current control algorithm is naturally applicable to converters with an arbitrary number of levels with reduced computational effort by virtue of the incorporation of switching restrictions which are necessary for reliable converter operation. The performance of the proposed algorithm is evaluated by means of computer simulations. (author)

  10. Influence of electropolishing current densities on sulfur generation at niobium surface

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, P.V., E-mail: tyagipv@ornl.gov [The Graduate University for Advanced Studies, Tsukuba, Ibaraki (Japan); Nishiwaki, M.; Noguchi, T.; Sawabe, M.; Saeki, T.; Hayano, H.; Kato, S. [KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2013-11-15

    We report the effect of different current densities on sulfur generation at Nb surface in the electropolishing (EP) with aged electrolyte. In this regard, we conducted a series of electropolishing (EP) experiments in aged EP electrolyte with high (≈50 mA/cm{sup 2}) and low (≈30 mA/cm{sup 2}) current densities on Nb surfaces. The experiments were carried out both for laboratory coupons and a real Nb single cell cavity with six witness samples located at three typical positions (equator, iris and beam pipe). Sample's surfaces were investigated by XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and EDX (energy dispersive X-ray spectroscopy). The surface analysis showed that the EP with a high current density produced a huge amount of sulfate/sulfite particles at Nb surface whereas the EP with a low current density was very helpful to mitigate sulfate/sulfite at Nb surface in both the experiments.

  11. Improved Model for Increased Surface Recombination Current in Irradiated Bipolar Junction Transistors

    Science.gov (United States)

    Barnaby, H. J.; Vermeire, B.; Campola, M. J.

    2015-08-01

    Current gain degradation in irradiated bipolar junction transistors is primarily due to excess base current caused by enhanced carrier recombination in the emitter-base space-charge region (SCR). Radiation-induced traps at the interface between silicon and the bipolar base oxide facilitate the recombination process primarily above the sensitive emitter-base junction. This leads to an increase in surface recombination current in the SCR, which is a non-ideal component of the BJT's base current characteristic under active bias conditions. In this paper, we derive a precise analytical model for surface recombination current that captures bias dependencies typically omitted from traditional models. This improved model is validated by comparisons to these traditional approaches.

  12. Density-matrix simulation of small surface codes under current and projected experimental noise

    Science.gov (United States)

    O'Brien, T. E.; Tarasinski, B.; DiCarlo, L.

    2017-09-01

    We present a density-matrix simulation of the quantum memory and computing performance of the distance-3 logical qubit Surface-17, following a recently proposed quantum circuit and using experimental error parameters for transmon qubits in a planar circuit QED architecture. We use this simulation to optimize components of the QEC scheme (e.g., trading off stabilizer measurement infidelity for reduced cycle time) and to investigate the benefits of feedback harnessing the fundamental asymmetry of relaxation-dominated error in the constituent transmons. A lower-order approximate calculation extends these predictions to the distance-5 Surface-49. These results clearly indicate error rates below the fault-tolerance threshold of the surface code, and the potential for Surface-17 to perform beyond the break-even point of quantum memory. However, Surface-49 is required to surpass the break-even point of computation at state-of-the-art qubit relaxation times and readout speeds.

  13. Predictive current control of permanent magnet synchronous motor based on linear active disturbance rejection control

    Science.gov (United States)

    Li, Kunpeng

    2017-01-01

    The compatibility problem between rapidity and overshooting in the traditional predictive current control structure is inevitable and difficult to solve by reason of using PI controller. A novel predictive current control (PCC) algorithm for permanent magnet synchronous motor (PMSM) based on linear active disturbance rejection control (LADRC) is presented in this paper. In order to displace PI controller, the LADRC strategy which consisted of linear state error feedback (LSEF) control algorithm and linear extended state observer (LESO), is designed based on the mathematic model of PMSM. The purpose of LSEF is to make sure fast response to load mutation and system uncertainties, and LESO is designed to estimate the uncertain disturbances. The principal structures of the proposed system are speed outer loop based on LADRC and current inner loop based on predictive current control. Especially, the instruction value of qaxis current in inner loop is derived from the control quantity which is designed in speed outer loop. The simulation is carried out in Matlab/Simulink software, and the results illustrate that the dynamic and static performances of proposed system are satisfied. Moreover the robust against model parameters mismatch is enhanced obviously.

  14. Variations in FASST Predictions of Soil Surface Temperatures

    National Research Council Canada - National Science Library

    Peck, Lindamae

    2006-01-01

    ..., initial volumetric soil moisture content, bulk density of the dry soil material, albedo (sunny days), and porosity. The thermal conductivity of the dry soil material has a minor effect on predicted soil temperature...

  15. Wind effect on currents in a thin surface layer of coastal waters faced open-sea

    International Nuclear Information System (INIS)

    Nakano, Masanao; Isozaki, Hisaaki; Isozaki, Tokuju; Nemoto, Masashi; Hasunuma, Keiichi; Kitamura, Takashi

    2009-01-01

    Two-years of continuous observation of wind and current were carried out to investigate the relationship between them in the coastal waters off Tokai-mura, Ibaraki prefecture. Three instruments to measure the current were set in a thin surface layer of 3 m above the strong pycnocline, which is a common feature in coastal waters. Both of the power spectra of wind and currents showed very similar features, an outstanding high peak at 24-hour period and a range of high peaks longer than several-days period. The long term variation of the wind field always contained north-wind component, which contributed to forming the southward current along the shore throughout the year. A high correlation coefficient (0.64) was obtained between the wind and the current at a depth of 0.5 m on the basis of the two-year observation. Harmonic analysis revealed that an outstanding current with 24-hour period was the S 1 component (meteorological tide), and was driven by land and sea breezes. These breezes also contained solar tidal components such as K 1 , P 1 and S 2 . These wind components added their own wind driven currents on the original tidal currents. This meant that land and sea breezes generated wind driven currents with solar tidal periods which behaved like astronomical tidal currents. As result, coastal currents contained pseudo tidal currents which behaved like astronomical tidal currents. (author)

  16. Surface current dynamics under sea breeze conditions observed by simultaneous HF radar, ADCP and drifter measurements

    Science.gov (United States)

    Sentchev, Alexei; Forget, Philippe; Fraunié, Philippe

    2017-04-01

    Ocean surface boundary layer dynamics off the southern coast of France in the NW Mediterranean is investigated by using velocity observations by high-frequency (HF) radars, surface drifting buoys and a downward-looking drifting acoustic Doppler current profiler (ADCP). The analysis confirms that velocities measured by HF radars correspond to those observed by an ADCP at the effective depth z f = k -1, where k is wavenumber of the radio wave emitted by the radar. The radials provided by the radars were in a very good agreement with in situ measurements, with the relative errors of 1 and 9 % and root mean square (RMS) differences of 0.02 and 0.04 m/s for monostatic and bistatic radar, respectively. The total radar-based velocities appeared to be slightly underestimated in magnitude and somewhat biased in direction. At the end of the survey period, the difference in the surface current direction, based on HF radar and ADCP data, attained 10°. It was demonstrated that the surface boundary layer dynamics cannot be reconstructed successfully without taking into the account velocity variation with depth. A significant misalignment of ˜30° caused by the sea breeze was documented between the HF radar (HFR-derived) surface current and the background current. It was also found that the ocean response to a moderate wind forcing was confined to the 4-m-thick upper layer. The respective Ekman current attained the maximum value of 0.15 m/s, and the current rotation was found to be lagging the wind by approximately 40 min, with the current vector direction being 15-20° to the left of the wind. The range of velocity variability due to wind forcing was found comparable with the magnitude of the background current variability.

  17. The molar surface Gibbs energy and prediction of surface tension of [Cnpy][DCA] (n = 3, 4, 5)

    International Nuclear Information System (INIS)

    Xing, Nannan; Dai, Bing; Ma, Xiaoxue; Wei, Jie; Pan, Yi; Guan, Wei

    2016-01-01

    Highlights: • The molar surface Gibbs energy, g s was put forword. • A new Eötvös equation is obtained. The molar surface enthalpy, h, is a temperature-independent constant. • By using g s and n D , the surface tensions of [C n py][DCA] (n = 3, 4, 5) were estimated. - Abstract: Three pyridinium-based ionic liquids of [C n py][DCA] (n = 3, 4, 5) (N-alkyl-pyridinium dicyanamide) were prepared and characterized by 1 H NMR ( 1 H nuclear magnetic resonance) spectroscopy, 13 C NMR ( 13 C nuclear magnetic resonance) spectroscopy. Their densities, surface tensions and refractive indices were measured at different temperatures. The molar surface Gibbs energy, g s , critical temperature, T c and Eötvös empirical parameter related to polarity, k E , were also calculated. In terms of the concept of molar surface Gibbs energy, g s , a new Eötvös equation was obtained. It is found that the slope of the new Eötvös equation is the molar surface entropy of the ILs and the intercept is the molar surface enthalpy which is a temperature-independent constant. By using the refractive index and the molar surface Gibbs energy, an equation to predict surface tension of the ILs was derived and the predicted values of the surface tension of [C n py][DCA] (n = 3, 4, 5) are all most the same with the corresponding experimental values.

  18. A Steel Ball Surface Quality Inspection Method Based on a Circumferential Eddy Current Array Sensor.

    Science.gov (United States)

    Zhang, Huayu; Xie, Fengqin; Cao, Maoyong; Zhong, Mingming

    2017-07-01

    To efficiently inspect surface defects on steel ball bearings, a new method based on a circumferential eddy current array (CECA) sensor was proposed here. The best probe configuration, in terms of the coil quality factor (Q-factor), magnetic field intensity, and induced eddy current density on the surface of a sample steel ball, was determined using 3-, 4-, 5-, and 6-coil probes, for analysis and comparison. The optimal lift-off from the measured steel ball, the number of probe coils, and the frequency of excitation current suitable for steel ball inspection were obtained. Using the resulting CECA sensor to inspect 46,126 steel balls showed a miss rate of ~0.02%. The sensor was inspected for surface defects as small as 0.05 mm in width and 0.1 mm in depth.

  19. A Steel Ball Surface Quality Inspection Method Based on a Circumferential Eddy Current Array Sensor

    Directory of Open Access Journals (Sweden)

    Huayu Zhang

    2017-07-01

    Full Text Available To efficiently inspect surface defects on steel ball bearings, a new method based on a circumferential eddy current array (CECA sensor was proposed here. The best probe configuration, in terms of the coil quality factor (Q-factor, magnetic field intensity, and induced eddy current density on the surface of a sample steel ball, was determined using 3-, 4-, 5-, and 6-coil probes, for analysis and comparison. The optimal lift-off from the measured steel ball, the number of probe coils, and the frequency of excitation current suitable for steel ball inspection were obtained. Using the resulting CECA sensor to inspect 46,126 steel balls showed a miss rate of ~0.02%. The sensor was inspected for surface defects as small as 0.05 mm in width and 0.1 mm in depth.

  20. A prediction of mars seismicity from surface faulting

    Science.gov (United States)

    Golombek, M.P.; Banerdt, W.B.; Tanaka, K.L.; Tralli, D.M.

    1992-01-01

    The shallow seismicity of Mars has been estimated by measurement of the total slip on faults visible on the surface of the planet throughout geologic time. Seismicity was calibrated with estimates based on surface structures on the moon and measured lunar seismicity that includes the entire seismogenic lithosphere. Results indicate that Mars is seismically active today, with a sufficient number of detectable marsquakes to allow seismic investigations of its interior.

  1. Surface tensions of multi-component mixed inorganic/organic aqueous systems of atmospheric significance: measurements, model predictions and importance for cloud activation predictions

    Directory of Open Access Journals (Sweden)

    D. O. Topping

    2007-01-01

    Full Text Available In order to predict the physical properties of aerosol particles, it is necessary to adequately capture the behaviour of the ubiquitous complex organic components. One of the key properties which may affect this behaviour is the contribution of the organic components to the surface tension of aqueous particles in the moist atmosphere. Whilst the qualitative effect of organic compounds on solution surface tensions has been widely reported, our quantitative understanding on mixed organic and mixed inorganic/organic systems is limited. Furthermore, it is unclear whether models that exist in the literature can reproduce the surface tension variability for binary and higher order multi-component organic and mixed inorganic/organic systems of atmospheric significance. The current study aims to resolve both issues to some extent. Surface tensions of single and multiple solute aqueous solutions were measured and compared with predictions from a number of model treatments. On comparison with binary organic systems, two predictive models found in the literature provided a range of values resulting from sensitivity to calculations of pure component surface tensions. Results indicate that a fitted model can capture the variability of the measured data very well, producing the lowest average percentage deviation for all compounds studied. The performance of the other models varies with compound and choice of model parameters. The behaviour of ternary mixed inorganic/organic systems was unreliably captured by using a predictive scheme and this was dependent on the composition of the solutes present. For more atmospherically representative higher order systems, entirely predictive schemes performed poorly. It was found that use of the binary data in a relatively simple mixing rule, or modification of an existing thermodynamic model with parameters derived from binary data, was able to accurately capture the surface tension variation with concentration. Thus

  2. The Current and Future Use of Ridge Regression for Prediction in Quantitative Genetics.

    Science.gov (United States)

    de Vlaming, Ronald; Groenen, Patrick J F

    2015-01-01

    In recent years, there has been a considerable amount of research on the use of regularization methods for inference and prediction in quantitative genetics. Such research mostly focuses on selection of markers and shrinkage of their effects. In this review paper, the use of ridge regression for prediction in quantitative genetics using single-nucleotide polymorphism data is discussed. In particular, we consider (i) the theoretical foundations of ridge regression, (ii) its link to commonly used methods in animal breeding, (iii) the computational feasibility, and (iv) the scope for constructing prediction models with nonlinear effects (e.g., dominance and epistasis). Based on a simulation study we gauge the current and future potential of ridge regression for prediction of human traits using genome-wide SNP data. We conclude that, for outcomes with a relatively simple genetic architecture, given current sample sizes in most cohorts (i.e., N ridge regression is slightly higher than the classical genome-wide association study approach of repeated simple regression (i.e., one regression per SNP). However, both capture only a small proportion of the heritability. Nevertheless, we find evidence that for large-scale initiatives, such as biobanks, sample sizes can be achieved where ridge regression compared to the classical approach improves predictive accuracy substantially.

  3. Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2004-04-01

    Full Text Available We study what effect a possible surface conductivity of Mercury has on the closure of magnetospheric currents by making six runs with a quasi-neutral hybrid simulation. The runs are otherwise identical but use different synthetic conductivity models: run 1 has a fully conducting planet, run 2 has a poorly conducting planet ( m and runs 3-6 have one of the hemispheres either in the dawn-dusk or day-night directions, conducting well, the other one being conducting poorly. Although the surface conductivity is not known from observations, educated guesses easily give such conductivity values that magnetospheric currents may close partly within the planet, and as the conductivity depends heavily on the mineral composition of the surface, the possibility of significant horizontal variations cannot be easily excluded. The simulation results show that strong horizontal variations may produce modest magnetospheric asymmetries. Beyond the hybrid simulation, we also briefly discuss the possibility that in the nightside there may be a lack of surface electrons to carry downward current, which may act as a further source of surface-related magnetospheric asymmetry. Key words. Magnetospheric physics (planetary magnetospheres; current systems; solar wind-magnetosphere interactions.6

  4. On the skill of seasonal sea surface temperature forecasts in the California Current System and its connection to ENSO variability

    Science.gov (United States)

    Jacox, Michael G.; Alexander, Michael A.; Stock, Charles A.; Hervieux, Gaëlle

    2017-03-01

    The California Current System (CCS) is a biologically productive Eastern Boundary Upwelling System that experiences considerable environmental variability on seasonal and interannual timescales. Given that this variability drives changes in ecologically and economically important living marine resources, predictive skill for regional oceanographic conditions is highly desirable. Here, we assess the skill of seasonal sea surface temperature (SST) forecasts in the CCS using output from Global Climate Forecast Systems in the North American Multi-Model Ensemble (NMME), and describe mechanisms that underlie SST predictability. A simple persistence forecast provides considerable skill for lead times up to 4 months, while skill above persistence is mostly confined to forecasts of late winter/spring and derives primarily from predictable evolution of ENSO-related variability. Specifically, anomalously weak (strong) equatorward winds are skillfully forecast during El Niño (La Niña) events, and drive negative (positive) upwelling anomalies and consequently warm (cold) temperature anomalies. This mechanism prevails during moderate to strong ENSO events, while years of ENSO-neutral conditions are not associated with significant forecast skill in the wind or significant skill above persistence in SST. We find also a strong latitudinal gradient in predictability within the CCS; SST forecast skill is highest off the Washington/Oregon coast and lowest off southern California, consistent with variable wind forcing being the dominant driver of SST predictability. These findings have direct implications for regional downscaling of seasonal forecasts and for short-term management of living marine resources.

  5. Test data on electrical contacts at high surface velocities and high current densities for homopolar generators

    International Nuclear Information System (INIS)

    Brennan, M.; Tolk, K.M.; Weldon, W.F.; Rylander, H.G.; Woodson, H.H.

    1977-01-01

    Test data is presented for one grade of copper graphite brush material, Morganite CMlS, over a wide range of surface velocities, atmospheres, and current densities that are expected for fast discharge (<100 ms) homopolar generators. The brushes were run on a copper coated 7075-T6 aluminum disk at surface speeds up to 277 m/sec. One electroplated copper and three flame sprayed copper coatings were used during the tests. Significant differences in contact voltage drops and surface mechanical properties of the copper coatings were observed

  6. Electrical conductivity and electron cyclotron current drive efficiencies for non-circular flux surfaces in tokamaks

    International Nuclear Information System (INIS)

    O'Brien, M.R.

    1989-01-01

    As is well known, the presence of electron trapping can strongly reduce the electrical conductivity and rf current drive efficiencies of tokamak plasmas. For example, the conductivity (in the low collisionality limit) of a flux surface with inverse aspect ratio ε=0.1 is approximately one half of the Spitzer conductivity (σ sp )for uniform magnetic fields. Previous estimates of these effects have assumed that the variation of magnetic field strength around a flux surface is given by the standard form for circular flux surfaces. (author) 11 refs., 4 figs

  7. Observations of the sub-inertial, near-surface East India Coastal Current

    Science.gov (United States)

    Mukhopadhyay, S.; Shankar, D.; Aparna, S. G.; Mukherjee, A.

    2017-09-01

    We present surface current measurements made using two pairs of HF (high-frequency) radars deployed on the east coast of India. The radar data, used in conjunction with data from acoustic Doppler current profiler (ADCP) measurements on the shelf and slope off the Indian east coast, confirm that the East India Coastal Current (EICC) flows poleward as a deep current during February-March. During the summer monsoon, when the EICC flows poleward, and October-December, when the EICC flows equatorward, the current is shallow (ADCP data does not always extend to the surface. Even within the seasons, however, the poleward and equatorward flows show variability at periods of the order of 20-45 days, implying that the EICC direction is the same over the top ∼100 m for short durations. The high spatial resolution of the HF radar data brings out features at scales shorter than those resolved by the altimeter and the high temporal resolution captures short bursts that are not captured in satellite-derived estimates of surface currents. The radar data show that the EICC, which is a boundary current, leaves a strong imprint on the current at the coast. Since the EICC is known to be affected significantly by remote forcing, this correlation between the boundary and nearshore current implies the need to use large-domain models even for simulating the nearshore current. Comparison with a simulation by a state-of-the-art Ocean General Circulation Model, run at a resolution of 0.1 ° × 0.1 ° , shows that the model is able to simulate only the low-frequency variability.

  8. Frequency and wavelength prediction of ultrasonic induced liquid surface waves.

    Science.gov (United States)

    Mahravan, Ehsan; Naderan, Hamid; Damangir, Ebrahim

    2016-12-01

    A theoretical investigation of parametric excitation of liquid free surface by a high frequency sound wave is preformed, using potential flow theory. Pressure and velocity distributions, resembling the sound wave, are applied to the free surface of the liquid. It is found that for impinging wave two distinct capillary frequencies will be excited: One of them is the same as the frequency of the sound wave, and the other is equal to the natural frequency corresponding to a wavenumber equal to the horizontal wavenumber of the sound wave. When the wave propagates in vertical direction, mathematical formulation leads to an equation, which has resonance frequency equal to half of the excitation frequency. This can explain an important contradiction between the frequency and the wavelength of capillary waves in the two cases of normal and inclined interaction of the sound wave and the free surface of the liquid. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Prediction of fluid velocity slip at solid surfaces

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Todd, Billy; Daivis, Peter

    2011-01-01

    methods, it allows us to directly compute the intrinsic wall-fluid friction coefficient rather than an empirical friction coefficient that includes all sources of friction for planar shear flow. The slip length predicted by our method is in excellent agreement with the slip length obtained from direct...

  10. Predicting fire severity using surface fuels and moisture

    Science.gov (United States)

    Pamela G. Sikkink; Robert E. Keane

    2012-01-01

    Fire severity classifications have been used extensively in fire management over the last 30 years to describe specific environmental or ecological impacts of fire on fuels, vegetation, wildlife, and soils in recently burned areas. New fire severity classifications need to be more objective, predictive, and ultimately more useful to fire management and planning. Our...

  11. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2010-01-01

    the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress......In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring...... behaviour. It compensates the load torque influence on the speed control setting a feed forward torque value, i.e. current reference value. The benefits are twice. The speed controller reaches immediately the speed reference value avoiding offsets which must be compensated by the weak integrator. Moreover...

  12. Models for prediction of global solar radiation on horizontal surface ...

    African Journals Online (AJOL)

    The estimation of global solar radiation continues to play a fundamental role in solar engineering systems and applications. This paper compares various models for estimating the average monthly global solar radiation on horizontal surface for Akure, Nigeria, using solar radiation and sunshine duration data covering years ...

  13. Climate Prediction Center (CPC) Global Land Surface Air Temperature Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A station observation-based global land monthly mean surface air temperature dataset at 0.5 0.5 latitude-longitude resolution for the period from 1948 to the present...

  14. Climate Prediction Center (CPC) Global Land Surface Air Temperature Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A station observation-based global land monthly mean surface air temperature dataset at 0.5 x 0.5 latitude-longitude resolution for the period from 1948 to the...

  15. An Information Retrieval Approach for Robust Prediction of Road Surface States.

    Science.gov (United States)

    Park, Jae-Hyung; Kim, Kwanho

    2017-01-28

    Recently, due to the increasing importance of reducing severe vehicle accidents on roads (especially on highways), the automatic identification of road surface conditions, and the provisioning of such information to drivers in advance, have recently been gaining significant momentum as a proactive solution to decrease the number of vehicle accidents. In this paper, we firstly propose an information retrieval approach that aims to identify road surface states by combining conventional machine-learning techniques and moving average methods. Specifically, when signal information is received from a radar system, our approach attempts to estimate the current state of the road surface based on the similar instances observed previously based on utilizing a given similarity function. Next, the estimated state is then calibrated by using the recently estimated states to yield both effective and robust prediction results. To validate the performances of the proposed approach, we established a real-world experimental setting on a section of actual highway in South Korea and conducted a comparison with the conventional approaches in terms of accuracy. The experimental results show that the proposed approach successfully outperforms the previously developed methods.

  16. Biodiversity in environmental assessment-current practice and tools for prediction

    International Nuclear Information System (INIS)

    Gontier, Mikael; Balfors, Berit; Moertberg, Ulla

    2006-01-01

    Habitat loss and fragmentation are major threats to biodiversity. Environmental impact assessment and strategic environmental assessment are essential instruments used in physical planning to address such problems. Yet there are no well-developed methods for quantifying and predicting impacts of fragmentation on biodiversity. In this study, a literature review was conducted on GIS-based ecological models that have potential as prediction tools for biodiversity assessment. Further, a review of environmental impact statements for road and railway projects from four European countries was performed, to study how impact prediction concerning biodiversity issues was addressed. The results of the study showed the existing gap between research in GIS-based ecological modelling and current practice in biodiversity assessment within environmental assessment

  17. ac electrokinetic micropumps: The effect of geometrical confinement, Faradaic current injection, and nonlinear surface capacitance

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bruus, Henrik; Ajdari, A.

    2006-01-01

    therefore extend the latter theories to account for three experimentally relevant effects: (i) vertical confinement of the pumping channel, (ii) Faradaic currents from electrochemical reactions at the electrodes, and (iii) nonlinear surface capacitance of the Debye layer. We report here that these effects...... indeed affect the pump performance in a way that we can rationalize by physical arguments....

  18. Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

    KAUST Repository

    Min, Shixiong

    2016-06-23

    While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

  19. Internal oscillating current-sustained RF plasmas: Parameters, stability, and potential for surface engineering

    DEFF Research Database (Denmark)

    Ostrikov, K.; Tsakadze, E.L.; Tsakadze, Z.L.

    2005-01-01

    A new source of low-frequency (0.46 MHz) inductively coupled plasmas sustained by the internal planar "unidirectional" RF current driven through a specially designed internal antenna configuration has been developed. The experimental results of the investigation of the optical and global argon pl...... applications and surface engineering. (c) 2005 Elsevier B.V. All rights reserved....

  20. Field representation inside arbitrary linear optical media by single surface currents

    NARCIS (Netherlands)

    Hoenders, BJ; Doosje, M; Knoester, J

    2004-01-01

    Recently a novel method has been proposed for the calculation of the scattering of an incoming electromagnetic wave by an arbitrarily shaped photonic crystal. The method rests on the representation of an arbitrary electromagnetic field inside a volume V by a fictitious surface current distribution

  1. Current limitations of trend curve analysis for the prediction of reactor PV embrittlement

    International Nuclear Information System (INIS)

    Gold, R.; McElroy, W.N.

    1987-01-01

    To define the effects of neutron radiation damage on LWR pressure-temperature operating limits and to assess fracture toughness of power reactor PV, trend curves for the prediction of PV embrittlement have been developed. These trend curves are very general PV embrittlement curves that are used to evaluate current PV status as well as to predict the future state of the PV. In such trend curves, the two main measures of radiation damage are the adjusted reference nil-ductility temperature ART/sub NDT/(RT/sub NDT/initial + ΔRT/sub NDT/) and the decrease in upper-shelf energy level determined from Charpy V notch impact tests. Current measures of neutron exposure most commonly used in trend curve analyses are fluence > 1 MeV and displacements per atom (dpa) in iron. Since trend curves play such a crucial role in the assessment of PV embrittlement of operating commercial LWR power plants, a critical appraisal of trend curve analysis is essential. To this end, current limitations in trend curve analysis for the prediction of reactor PV embrittlement are examined. It is concluded that a number of systematic effects can arise because environmental differences exist between test reactors, surveillance capsule locations, and the actual irradiation conditions that accrue within the PV of an operating LWR commercial power plant. An irradiation test program is advanced to investigate these systematic effects and to produce the requisite data needed to correct for such systematic biases in trend curve analysis

  2. Slow and Steady: Ocean Circulation. The Influence of Sea Surface Height on Ocean Currents

    Science.gov (United States)

    Haekkinen, Sirpa

    2000-01-01

    The study of ocean circulation is vital to understanding how our climate works. The movement of the ocean is closely linked to the progression of atmospheric motion. Winds close to sea level add momentum to ocean surface currents. At the same time, heat that is stored and transported by the ocean warms the atmosphere above and alters air pressure distribution. Therefore, any attempt to model climate variation accurately must include reliable calculations of ocean circulation. Unlike movement of the atmosphere, movement of the ocean's waters takes place mostly near the surface. The major patterns of surface circulation form gigantic circular cells known as gyres. They are categorized according to their general location-equatorial, subtropical, subpolar, and polar-and may run across an entire ocean. The smaller-scale cell of ocean circulation is known' as an eddy. Eddies are much more common than gyres and much more difficult to track in computer simulations of ocean currents.

  3. High-Resolution Specification of the Land and Ocean Surface for Improving Regional Mesoscale Model Predictions

    Science.gov (United States)

    Case, Jonathan L.; Lazarus, Steven M.; Splitt, Michael E.; Crosson, William L.; Lapenta, William M.; Jedlovec, Gary J.; Peters-Lidard, Christa D.

    2008-01-01

    The exchange of energy and moisture between the Earth's surface and the atmospheric boundary layer plays a critical role in many meteorological processes. High-resolution, accurate representations of surface properties such as sea-surface temperature (SST), soil temperature and moisture content, ground fluxes, and vegetation are necessary to better understand the Earth-atmosphere interactions and improve numerical predictions of sensible weather. The NASA Short-term Prediction Research and Transition (SPoRT) Center has been conducting separate studies to examine the impacts of high-resolution land-surface initialization data from the Goddard Space Flight Center Land Information System (LIS) on subsequent WRF forecasts, as well as the influence of initializing WRF with SST composites derived from the MODIS instrument. This current project addresses the combined impacts of using high-resolution lower boundary data over both land (LIS data) and water (MODIS SSTs) on the subsequent daily WRF forecasts over Florida during May 2004. For this experiment, the WRF model is configured to run on a nested domain with 9- km and 3-kin grid spacing, centered on the Florida peninsula and adjacent coastal waters of the Gulf of Mexico and Atlantic Ocean. A control configuration of WRF is established to take all initial condition data from the NCEP Eta model. Meanwhile, two WRF experimental runs are configured to use high-resolution initialization data from (1) LIS land-surface data only, and (2) a combination of LIS data and high-resolution MODIS SST composites. The experiment involves running 24-hour simulations of the control WRF configuration, the MS-initialized WRF, and the LIS+MODIS-initialized WRF daily for the entire month of May 2004. All atmospheric data for initial and boundary conditions for the Control, LIS, and LIS+MODIS runs come from the NCEP Eta model on a 40-km grid. Verification statistics are generated at land surface observation sites and buoys, and the impacts

  4. Predicting the behavioural impact of transcranial direct current stimulation: issues and limitations

    Directory of Open Access Journals (Sweden)

    Archy Otto De Berker

    2013-10-01

    Full Text Available The transcranial application of weak currents to the human brain has enjoyed a decade of success, providing a simple and powerful tool for non-invasively altering human brain function. However, our understanding of current delivery and its impact upon neural circuitry leaves much to be desired. We argue that the credibility of conclusions drawn with tDCS is contingent upon realistic explanations of how tDCS works, and that our present understanding of tDCS limits the technique’s use to localize function in the human brain. We outline two central issues where progress is required: the localization of currents, and predicting their functional consequence. We encourage experimenters to eschew simplistic explanations of mechanisms of transcranial current stimulation. We suggest the use of individualized current modelling, together with computational neurostimulation to inform mechanistic frameworks in which to interpret the physiological impact of tDCS. We hope that through mechanistically richer descriptions of current flow and action, insight into the biological processes by which transcranial currents influence behaviour can be gained, leading to more effective stimulation protocols and empowering conclusions drawn with tDCS.

  5. Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

    International Nuclear Information System (INIS)

    Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu

    2015-01-01

    Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

  6. Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu, E-mail: sde@che.iitkgp.ernet.in

    2015-12-31

    Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

  7. Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

    International Nuclear Information System (INIS)

    Luo, Dian; Tang, Guangze; Ma, Xinxin; Gu, Le; Sun, Mingren; Wang, Liqin

    2015-01-01

    Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm 2 . Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm 2 ) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation

  8. Prediction of average annual surface temperature for both flexible and rigid pavements

    Directory of Open Access Journals (Sweden)

    Karthikeyan LOGANATHAN

    2017-12-01

    Full Text Available The surface temperature of pavements is a critical attribute during pavement design. Surface temperature must be measured at locations of interest based on time-consuming field tests. The key idea of this study is to develop a temperature profile model to predict the surface temperature of flexible and rigid pavements based on weather parameters. Determination of surface temperature with traditional techniques and sensors are replaced by a newly developed method. The method includes the development of a regression model to predict the average annual surface temperature based on weather parameters such as ambient air temperature, relative humidity, wind speed, and precipitation. Detailed information about temperature and other parameters are extracted from the Federal Highway Administration's (FHWA Long Term Pavement Performance (LTPP online database. The study was conducted on 61 pavement sections in the state of Alabama for a 10-year period. The developed model would predict the average annual surface temperature based on the known weather parameters. The predicted surface temperature model for asphalt pavements was very reliable and can be utilized while designing a pavement. The study was also conducted on seven rigid pavement sections in Alabama to predict their surface temperature, in which a successful model was developed. The outcome of this study would help the transportation agencies by saving time and effort invested in expensive field tests to measure the surface temperature of pavements.

  9. Improved Modeling and Prediction of Surface Wave Amplitudes

    Science.gov (United States)

    2017-05-31

    data does not license the holder or any other person or corporation; or convey any rights or permission to manufacture, use, or sell any patented... advantages of the membrane surface wave technique are that 1) it is orders of magnitude faster than 3-dimensional finite-difference; and 2) it...0.5 km depth. Although the CMT sources should more accurately reproduce the observed signals from each event, they have two disadvantages : 1) in the

  10. Ultrafast terahertz control of extreme tunnel currents through single atoms on a silicon surface

    DEFF Research Database (Denmark)

    Jelic, Vedran; Iwaszczuk, Krzysztof; Nguyen, Peter H.

    2017-01-01

    Ultrafast control of current on the atomic scale is essential for future innovations in nanoelectronics. Extremely localized transient electric fields on the nanoscale can be achieved by coupling picosecond duration terahertz pulses to metallic nanostructures. Here, we demonstrate terahertz...... scanning tunnelling microscopy (THz-STM) in ultrahigh vacuum as a new platform for exploring ultrafast non-equilibrium tunnelling dynamics with atomic precision. Extreme terahertz-pulse-driven tunnel currents up to 10(7) times larger than steady-state currents in conventional STM are used to image...... individual atoms on a silicon surface with 0.3nm spatial resolution. At terahertz frequencies, the metallic-like Si(111)-(7 x 7) surface is unable to screen the electric field from the bulk, resulting in a terahertz tunnel conductance that is fundamentally different than that of the steady state. Ultrafast...

  11. Climate-Induced Change in South Central Siberia: Predictions Versus Current Observations

    Science.gov (United States)

    Soja, A. J.; Tchebakova, N. M.; Parfenova, E. I.; Shishikin, A.; Kanzai, V.; Westberg, D. J.; Sukhinin, A. I.; Ivanova, G. A.; Stackhouse, P. W.

    2007-12-01

    Atmosphere Ocean General Circulations Models (AOGCM) are in agreement that Siberia is expected to experience warming in excess of 40% above global mean temperature increases by 2100. Moreover, it is predicted temperature increases will be evident in both the summer and winter. In association with changes in climate, the extent of the fire season, the amount of area burned and fire severity are predicted to increase. Fire regime increases are predicted to be the catalyst for ecosystem change, which will force ecosystems to move more rapidly towards equilibrium with the climate. Bioclimatic model results predict expansive changes in ecosystems, from a landscape dominated by taiga to a landscape dominated by steppe and forest-steppe. The focus of this investigation is on south, central Siberia in the Sayan Mountains and the Tyvan Republic, where one would expect to find the initial signs of climate change. The Sayan mountain range offers relatively abrupt change in ecosystems that are often defined by altitude, temperature and precipitation. Tyva is located at a vulnerable southern border, south of the Sayan, and contains 9 Biospheric Reserves, each representing distinct ecosystems. Additionally, Tyva is the home of several relic Pinus sylvestris forests. In these regions, January temperature increases have exceeded those predicted by the Hadley Centre scenario for 2090, and July temperatures are well below predictions. Predicted increases in rainfall are not apparent, and generally, precipitation change has been negative. The growing season length has already increased by about 6 to 12 days. Consequently, several of the relic pine forests have burned (some repeatedly), and natural regeneration is not visible at several sites, even one that had been re-planted on several occasions. In the last decades, these regions have experienced changes in climate and, potentially, initial signs of ecosystem change. In this report, we present a concentrated view of one region that

  12. Current psychiatric disorders in patients with epilepsy are predicted by maltreatment experiences during childhood.

    Science.gov (United States)

    Labudda, Kirsten; Illies, Dominik; Herzig, Cornelia; Schröder, Katharina; Bien, Christian G; Neuner, Frank

    2017-09-01

    Childhood maltreatment has been shown to be a risk factor for the development of psychiatric disorders. Although the prevalence of psychiatric disorders is high in epilepsy patients, it is unknown if childhood maltreatment experiences are elevated compared to the normal population and if early maltreatment is a risk factor for current psychiatric comorbidities in epilepsy patients. This is the main purpose of this study. Structured interviews were used to assess current Axis I diagnoses in 120 epilepsy patients from a tertiary Epilepsy Center (34 TLE patients, 86 non-TLE patients). Childhood maltreatment in the family and peer victimization were assessed with validated questionnaires. Patients' maltreatment scores were compared with those of a representative matched control group. Logistic regression analysis was conducted to assess the potential impact of childhood maltreatment on current psychiatric comorbidity in epilepsy patients. Compared to a matched control group, epilepsy patients had higher emotional and sexual maltreatment scores. Patients with a current psychiatric diagnosis reported more family and peer maltreatment than patients without a psychiatric disorder. Family maltreatment scores predicted the likelihood of a current psychiatric disorder. TLE patients did not differ from non-TLE patients according to maltreatment experiences and rates of current psychiatric disorders. Our findings suggest that in epilepsy patients emotional and sexual childhood maltreatment is experienced more often than in the normal population and that early maltreatment is a general risk factor for psychiatric comorbidities in this group. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Design and implementation of predictive current control of three-phase PWM rectifier using space-vector modulation (SVM)

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Gaubert, Jean-Paul; Krim, Fateh

    2010-01-01

    This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α-β and rotating d-q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.

  14. Predicting Biological Age from a Skin Surface Capacitive Analysis

    Science.gov (United States)

    Bevilacqua, Alessandro; Gherardi, Alessandro; Ferri, Massimo

    The skin is the largest (and the most exposed) organ of the body both in terms of surface area and weight. Its care is of great importance for both aesthetics and health issues. Often, the skin appearance gives us information about the skin health status as well as hints at the biological age. Therefore, the skin surface characterization is of great significance for dermatologists as well as for cosmetic scientists in order to evaluate the effectiveness of medical or cosmetic treatments. So far, no in vivo measurements regarding skin topography characterization could be achieved routinely to evaluate skin aging. This work describes how a portable capacitive device, normally used for fingerprint acquisition, can be utilized to achieve measures of skin aging routinely. The capacitive images give a high resolution (50 μm) representation of skin topography, in terms of wrinkles and cells. In this work, we have addressed the latter: through image segmentation techniques, cells have been localized and identified and a feature related to their area distribution has been generated. Accurate experiments accomplished in vivo show how the feature we conceived is linearly related to skin aging. Besides, since this finding has been achieved using a low cost portable device, this could boost research in this field as well as open doors to an application based on an embedded system.

  15. Estimated venous return surface and cardiac output curve precisely predicts new hemodynamics after volume change.

    Science.gov (United States)

    Sugimachi, Masaru; Sunagawa, Kenji; Uemura, Kazunori; Kamiya, Atsunori; Shimizu, Shuji; Inagaki, Masashi; Shishido, Toshiaki

    2010-01-01

    In our extended Guyton's model, the ability of heart to pump blood is characterized by a cardiac output curve and the ability of vasculature to pool blood by a venous return surface. These intersect in a three-dimensional coordinate system at the operating right atrial pressure, left atrial pressure, and cardiac output. The baseline cardiac output curve and venous return surface and their changes after volume change would predict new hemodynamics. The invasive methods needed to precisely characterize cardiac output curve and venous return surface led us to aim at estimating cardiac output curve and venous return surface from a single hemodynamic measurement. Using the average values for two logarithmic function parameters, and for two slopes of a surface, we were able to estimate cardiac output curve and venous return surface. The estimated curve and surface predicted new hemodynamics after volume change precisely.

  16. Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2004-04-01

    Full Text Available We study what effect a possible surface conductivity of Mercury has on the closure of magnetospheric currents by making six runs with a quasi-neutral hybrid simulation. The runs are otherwise identical but use different synthetic conductivity models: run 1 has a fully conducting planet, run 2 has a poorly conducting planet ( $sigma{=}10^{-8} Omega^{-1}$ m$^{-1}$ and runs 3-6 have one of the hemispheres either in the dawn-dusk or day-night directions, conducting well, the other one being conducting poorly. Although the surface conductivity is not known from observations, educated guesses easily give such conductivity values that magnetospheric currents may close partly within the planet, and as the conductivity depends heavily on the mineral composition of the surface, the possibility of significant horizontal variations cannot be easily excluded. The simulation results show that strong horizontal variations may produce modest magnetospheric asymmetries. Beyond the hybrid simulation, we also briefly discuss the possibility that in the nightside there may be a lack of surface electrons to carry downward current, which may act as a further source of surface-related magnetospheric asymmetry.

    Key words. Magnetospheric physics (planetary magnetospheres; current systems; solar wind-magnetosphere interactions.6

  17. Determining the near-surface current profile from measurements of the wave dispersion relation

    Science.gov (United States)

    Smeltzer, Benjamin; Maxwell, Peter; Aesøy, Eirik; Ellingsen, Simen

    2017-11-01

    The current-induced Doppler shifts of waves can yield information about the background mean flow, providing an attractive method of inferring the current profile in the upper layer of the ocean. We present measurements of waves propagating on shear currents in a laboratory water channel, as well as theoretical investigations of inversion techniques for determining the vertical current structure. Spatial and temporal measurements of the free surface profile obtained using a synthetic Schlieren method are analyzed to determine the wave dispersion relation and Doppler shifts as a function of wavelength. The vertical current profile can then be inferred from the Doppler shifts using an inversion algorithm. Most existing algorithms rely on a priori assumptions of the shape of the current profile, and developing a method that uses less stringent assumptions is a focus of this study, allowing for measurement of more general current profiles. The accuracy of current inversion algorithms are evaluated by comparison to measurements of the mean flow profile from particle image velocimetry (PIV), and a discussion of the sensitivity to errors in the Doppler shifts is presented.

  18. The coupling of mechanical dynamics and induced currents in plates and surfaces

    International Nuclear Information System (INIS)

    Weissenburger, D.W.; Bialek, J.M.

    1986-10-01

    Significant mechanical reactions and deflections may be produced when electrical eddy currents induced in a conducting structure by transformer-like electromotive forces interact with background magnetic fields. Additional eddy currents induced by structural motion through the background fields modify both the mechanical and electrical dynamic behavior of the system. The observed effects of these motional eddy currents are sometimes referred to as magnetic damping and magnetic stiffness. This paper addresses the coupled structural deformation and eddy currents in flat plates and simple two-dimensional surfaces in three-space. A coupled system of equations has been formulated using finite element techniques for the mechanical aspects and a mesh network method for the electrical aspects of the problem

  19. Near-surface current meter array measurements of internal gravity waves

    Energy Technology Data Exchange (ETDEWEB)

    Jones, H.B.E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    We have developed various processing algorithms used to estimate the wave forms produced by hydrodynamic Internal Waves. Furthermore, the estimated Internal Waves are used to calculate the Modulation Transfer Function (MTF) which relates the current and strain rate subsurface fields to surface scattering phenomenon imaged by radar. Following a brief discussion of LLNL`s measurement platform (a 10 sensor current meter array) we described the generation of representative current and strain rate space-time images from measured or simulated data. Then, we present how our simulation capability highlighted limitations in estimating strain rate. These limitations spurred the application of beamforming techniques to enhance our estimates, albeit at the expense of collapsing our space-time images to 1-D estimates. Finally, we discuss progress with regard to processing the current meter array data captured during the recent Loch Linnhe field trials.

  20. Time varying eddy currents on a conducting surface in 3-D using a network mesh method

    International Nuclear Information System (INIS)

    Christensen, U.R.

    1979-04-01

    The method presented in this paper was developed for the purpose of analyzing the eddy currents in the TFTR vacuum vessel. The basic principle in this method lies in representing a conducting surface as a network comprised of a number of branches. Each branch has a resistance and a self-inductance as well as mutuals to all other branches. The resulting branch resistance and branch inductance matrices are transformed into mesh matrices by a conventional network procedure. By using these mesh matrices a set of simultaneous differential equations is then established. The eddy currents are then found by using a standard method for solving simultaneous differential equations

  1. The North Atlantic Oscillation, Surface Current Velocities, and SST Changes in the Subpolar North Atlantic.

    Science.gov (United States)

    Flatau, Maria K.; Talley, Lynne; Niiler, Pearn P.

    2003-07-01

    Changes in surface circulation in the subpolar North Atlantic are documented for the recent interannual switch in the North Atlantic Oscillation (NAO) index from positive values in the early 1990s to negative values in 1995/96. Data from Lagrangian drifters, which were deployed in the North Atlantic from 1992 to 1998, were used to compute the mean and varying surface currents. NCEP winds were used to calculate the Ekman component, allowing isolation of the geostrophic currents. The mean Ekman velocities are considerably smaller than the mean total velocities that resemble historical analyses. The northeastward flow of the North Atlantic Current is organized into three strong cores associated with topography: along the eastern boundary in Rockall Trough, in the Iceland Basin (the subpolar front), and on the western flank of the Reykjanes Ridge (Irminger Current). The last is isolated in this Eulerian mean from the rest of the North Atlantic Current by a region of weak velocities on the east side of the Reykjanes Ridge.The drifter results during the two different NAO periods are compared with geostrophic flow changes calculated from the NASA/Pathfinder monthly gridded sea surface height (SSH) variability products and the Advanced Very High Resolution Radiometer (AVHRR) SST data. During the positive NAO years the northeastward flow in the North Atlantic Current appeared stronger and the circulation in the cyclonic gyre in the Irminger Basin became more intense. This was consistent with the geostrophic velocities calculated from altimetry data and surface temperature changes from AVHRR SST data, which show that during the positive NAO years, with stronger westerlies, the subpolar front was sharper and located farther east. SST gradients intensified in the North Atlantic Current, Irminger Basin, and east of the Shetland Islands during the positive NAO phase, associated with stronger currents. SST differences between positive and negative NAO years were consistent with

  2. Preface: Current perspectives in modelling, monitoring, and predicting geophysical fluid dynamics

    Science.gov (United States)

    Mancho, Ana M.; Hernández-García, Emilio; López, Cristóbal; Turiel, Antonio; Wiggins, Stephen; Pérez-Muñuzuri, Vicente

    2018-02-01

    The third edition of the international workshop Nonlinear Processes in Oceanic and Atmospheric Flows was held at the Institute of Mathematical Sciences (ICMAT) in Madrid from 6 to 8 July 2016. The event gathered oceanographers, atmospheric scientists, physicists, and applied mathematicians sharing a common interest in the nonlinear dynamics of geophysical fluid flows. The philosophy of this meeting was to bring together researchers from a variety of backgrounds into an environment that favoured a vigorous discussion of concepts across different disciplines. The present Special Issue on Current perspectives in modelling, monitoring, and predicting geophysical fluid dynamics contains selected contributions, mainly from attendants of the workshop, providing an updated perspective on modelling aspects of geophysical flows as well as issues on prediction and assimilation of observational data and novel tools for describing transport and mixing processes in these contexts. More details on these aspects are discussed in this preface.

  3. Morphological features of the copper surface layer under sliding with high density electric current

    Energy Technology Data Exchange (ETDEWEB)

    Fadin, V. V., E-mail: fvv@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Aleutdinova, M. I., E-mail: aleut@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Seversk Technological Institute, Branch of State Autonomous Educational Institution of Higher Professional Education “National Research Nuclear University “MEPhI”, Seversk, 636036 (Russian Federation); Rubtsov, V. Ye., E-mail: rvy@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Aleutdinova, V. A., E-mail: valery-aleut@yandex.ru [National Research St. Petersburg State Polytechnical University, St. Petersburg, 195251 (Russian Federation)

    2015-10-27

    Conductivity and wear intensity of copper under the influence of dry friction and electric current with contact density higher 100 A/cm{sup 2} are presented. It is shown that an increase in hardness and heat outflow from a friction zone leads to the reduction of wear intensity and current contact density increase corresponding to the beginning of catastrophic wear. Structural changes, such as the formation of FeO oxide and α-Fe particles in the copper surface layer, have also been found. It is observed that a worn surface is deformed according to a viscous liquid mechanism. Such singularity is explained in terms of appearance of high-excited atomic states in deforming micro-volumes near contact spots that lead to easy stress relaxation by local plastic shears in the vicinity of stress concentrators. In common this effect allows to achieve high wear resistance.

  4. Prediction of hydrocarbon surface seepage potential using infiltrometer data

    Science.gov (United States)

    Connors, J. J.; Jackson, J. L.; Engle, R. A.; Connors, J. L.

    2017-12-01

    Environmental regulations addressing above-ground storage tank (AST) spill control activities typically require owners/operators to demonstrate that local soil permeability values are low enough to adequately contain released liquids while emergency-response procedures are conducted. Frequently, geotechnical borings and soil samples/analyses, and/or monitoring well slug-test analyses, are used to provide hydraulic conductivity data for the required calculations. While these techniques are useful in assessing hydrological characteristics of the subsurface, they do not always assess the uppermost surface soil layer, where the bulk of the containment can occur. This layer may have been subject to long-term permeability-reduction by activities such as compaction by vehicular and foot traffic, micro-coatings by hydrophobic pollutants, etc. This presentation explores the usefulness of dual-ring infiltrometers, both in field and bench-scale tests, to rapidly acquire actual hydraulic conductivity values of surficial soil layers, which can be much lower than subsurface values determined using more traditional downhole geotechnical and hydrogeological approaches.

  5. Master Sintering Surface: A practical approach to its construction and utilization for Spark Plasma Sintering prediction

    Directory of Open Access Journals (Sweden)

    Pouchly V.

    2012-01-01

    Full Text Available The sintering is a complex thermally activated process, thus any prediction of sintering behaviour is very welcome not only for industrial purposes. Presented paper shows the possibility of densification prediction based on concept of Master Sintering Surface (MSS for pressure assisted Spark Plasma Sintering (SPS. User friendly software for evaluation of the MSS is presented. The concept was used for densification prediction of alumina ceramics sintered by SPS.

  6. Detection of milled 100Cr6 steel surface by eddy current and incremental permeance methods

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy; Neslušan, M.; Stupakov, Alexandr

    2017-01-01

    Roč. 87, Apr (2017), s. 15-23 ISSN 0963-8695 R&D Projects: GA ČR GB14-36566G; GA ČR GA13-18993S Institutional support: RVO:68378271 Keywords : Eddy currents * hard milling * incremental permeance * magnetic materials * surface characterization Subject RIV: JB - Sensors, Measurment, Regulation OBOR OECD: Electrical and electronic engineering Impact factor: 2.726, year: 2016

  7. Station-keeping control of an unmanned surface vehicle exposed to current and wind disturbances

    OpenAIRE

    Sarda, Edoardo I.; Qu, Huajin; Bertaska, Ivan R.; von Ellenrieder, Karl D.

    2017-01-01

    Field trials of a 4 meter long, 180 kilogram, unmanned surface vehicle (USV) have been conducted to evaluate the performance of station-keeping heading and position controllers in an outdoor marine environment disturbed by wind and current. The USV has a twin hull configuration and a custom-designed propulsion system, which consists of two azimuthing thrusters, one for each hull. Nonlinear proportional derivative, backstepping and sliding mode feedback controllers were tested in winds of abou...

  8. Dynamics at Solid State Surfaces and Interfaces, Volume 1 Current Developments

    CERN Document Server

    Bovensiepen, Uwe; Wolf, Martin

    2010-01-01

    This two-volume work covers ultrafast structural and electronic dynamics of elementary processes at solid surfaces and interfaces, presenting the current status of photoinduced processes. Providing valuable introductory information for newcomers to this booming field of research, it investigates concepts and experiments, femtosecond and attosecond time-resolved methods, as well as frequency domain techniques. The whole is rounded off by a look at future developments.

  9. Model Predictive Current Control for High-Power Grid-Connected Converters with Output LCL Filter

    DEFF Research Database (Denmark)

    Delpino, Hernan Anres Miranda; Teodorescu, Remus; Rodriguez, Pedro

    2009-01-01

    A model predictive control strategy for a highpower, grid connected 3-level neutral clamped point converter is presented. Power losses constraints set a limit on commutation losses so reduced switching frequency is required, thus producing low frequency current harmonics. To reduce these harmonics...... an LCL filter is used. The proposed control strategy allows control of the active and reactive power fed into the grid, reduce the switching frequency within acceptable operational margins and keep balance of the DC-link capacitor voltages while avoiding excitation of the filter resonance frequencies....

  10. Neutral current (anti)neutrino scattering: Relativistic mean field and superscaling predictions

    International Nuclear Information System (INIS)

    González-Jiménez, R.; Ivanov, M.V.; Barbaro, M.B.; Caballero, J.A.; Udias, J.M.

    2013-01-01

    We evaluate the neutral current quasi-elastic neutrino cross section within two nuclear models: the SuSA model, based on the superscaling behavior of electron scattering data, and the RMF model, based on relativistic mean field theory. We also estimate the ratio (νp→νp)/(νN→νN) and compare with the MiniBooNE experimental data, performing a fit of the parameters M A and g A (s) within the two models. Finally, we present our predictions for antineutrino scattering.

  11. Prediction of burnout of a conduction-cooled BSCCO current lead

    International Nuclear Information System (INIS)

    Seol, S.Y.; Cha, Y.S.; Niemann, R.C.; Hull, J.R.

    1996-01-01

    A one-dimensional heat conduction model is employed to predict burnout of a Bi 2 Sr 2 CaCu 2 O 8 current lead. The upper end of the lead is assumed to be at 77 K and the lower end is at 4 K. The results show that burnout always occurs at the warmer end of the lead. The lead reaches its burnout temperature in two distinct stage. Initially, the temperature rises slowly when part of the lead is in flux-flow state. As the local temperature reaches the critical temperature, it begins to increase sharply. Burnout time depends strongly on flux-flow resistivity

  12. Harmonic current prediction by impedance modeling of grid-tied inverters

    DEFF Research Database (Denmark)

    Pereira, Heverton A.; Freijedo, Francisco D.; Silva, M. M.

    2017-01-01

    Grid-tied inverters are the main responsible for the successful integration of photovoltaic (PV) plants in the power grid. Two important challenges are the integration of power plants based-inverters and their contribution to the power system quality. This work analyzes the features of inverter....... In grids with harmonic voltages, impedance models can predict the current distortion for all active power injection scenarios. Furthermore, measurements in a 1.4 MW PV plant connected in a distributed grid are used to validate the simulation based on impedance models during different power injections...

  13. Predicting the potential distribution in China of Euwallacea fornicates (Eichhoff) under current and future climate conditions

    OpenAIRE

    Ge, Xuezhen; Jiang, Chao; Chen, Linghong; Qiu, Shuang; Zhao, Yuxiang; Wang, Tao; Zong, Shixiang

    2017-01-01

    Euwallacea fornicatus (Eichhoff) is an important forest pest that has caused serious damage in America and Vietnam. In 2014, it attacked forests of Acer trialatum in the Yunnan province of China, creating concern in China?s Forestry Bureau. We used the CLIMEX model to predict and compare the potential distribution for E. fornicates in China under current (1981?2010) and projected climate conditions (2011?2040) using one scenario (RCP8.5) and one global climate model (GCM), CSIRO-Mk3-6-0. Unde...

  14. Prediction and correlation of surface tension of naphtha reformate and crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, E.I.; Al-Sahhaf, T.A.; Fahim, M.A. [Kuwait University (Kuwait). Chemical Engineering Dept.

    1995-04-01

    Six methods were tested for the prediction of the surface tension of naphtha reformate and crude oil fractions. The corresponding-state method gave the lowest deviation from experimental values for single cuts. The surface tension-density correlation method gave the lowest deviation for a blend of several cuts. 12 refs., 14 tabs.

  15. Prediction of viscosities and surface tensions of fuels using a new corresponding states model

    DEFF Research Database (Denmark)

    Queimada, A.J.; Rolo, L.I.; Caco, A.I.

    2006-01-01

    While some properties of diesels are cheap, easy and fast to measure, such as densities, others such as surface tensions and viscosities are expensive and time consuming. A new approach that uses some basic information such as densities to predict viscosities and surface tensions is here proposed...

  16. Poleward propagating subinertial alongshore surface currents off the U.S. West Coast

    KAUST Repository

    Kim, Sung Yong

    2013-12-01

    The network comprising 61 high-frequency radar systems along the U.S. West Coast (USWC) provides a unique, high resolution, and broad scale view of ocean surface circulation. Subinertial alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100-300) km d -1 that are consistent with historical in situ observations off the USWC and that can be possibly interpreted as coastally trapped waves (CTWs). The propagating signals in the slow mode are partly observed in southern California, which may result from scattering and reflection of higher-mode CTWs due to curvature of shoreline and bathymetry near Point Conception, California. On the other hand, considering the order of the phase speed in the slow mode, the poleward propagating signals may be attributed to alongshore advection or pressure-driven flows. A statistical regression of coastal winds at National Data Buoy Center buoys on the observed surface currents partitions locally and remotely wind-forced components, isolates footprints of the equatorward propagating storm events in winter off the USWC, and shows the poleward propagating signals year round. Key Points A unique resource to examine synoptic-scale alongshore variability Isolation of equatorward wind events in winter using a statistical model Poleward propagating surface signals year-round © 2013. American Geophysical Union. All Rights Reserved.

  17. Characterization of the Deep Water Surface Wave Variability in the California Current Region

    Science.gov (United States)

    Villas Bôas, Ana B.; Gille, Sarah T.; Mazloff, Matthew R.; Cornuelle, Bruce D.

    2017-11-01

    Surface waves are crucial for the dynamics of the upper ocean not only because they mediate exchanges of momentum, heat, energy, and gases between the ocean and the atmosphere, but also because they determine the sea state. The surface wave field in a given region is set by the combination of local and remote forcing. The present work characterizes the seasonal variability of the deep water surface wave field in the California Current region, as retrieved from over two decades of satellite altimetry data combined with wave buoys and wave model hindcast (WaveWatch III). In particular, the extent to which the local wind modulates the variability of the significant wave height, peak period, and peak direction is assessed. During spring/summer, regional-scale wind events of up to 10 m/s are the dominant forcing for waves off the California coast, leading to relatively short-period waves (8-10 s) that come predominantly from the north-northwest. The wave climatology throughout the California Current region shows average significant wave heights exceeding 2 m during most of the year, which may have implications for the planning and retrieval methods of the Surface Water and Ocean Topography (SWOT) satellite mission.

  18. Prevalence of current patterns and predictive trends of multidrug-resistant Salmonella Typhi in Sudan

    Directory of Open Access Journals (Sweden)

    Ayman A. Elshayeb

    2017-11-01

    Full Text Available Abstract Background Enteric fever has persistence of great impact in Sudanese public health especially during rainy season when the causative agent Salmonella enterica serovar Typhi possesses pan endemic patterns in most regions of Sudan - Khartoum. Objectives The present study aims to assess the recent state of antibiotics susceptibility of Salmonella Typhi with special concern to multidrug resistance strains and predict the emergence of new resistant patterns and outbreaks. Methods Salmonella Typhi strains were isolated and identified according to the guidelines of the International Standardization Organization and the World Health Organization. The antibiotics susceptibilities were tested using the recommendations of the Clinical Laboratories Standards Institute. Predictions of emerging resistant bacteria patterns and outbreaks in Sudan were done using logistic regression, forecasting linear equations and in silico simulations models. Results A total of 124 antibiotics resistant Salmonella Typhi strains categorized in 12 average groups were isolated, different patterns of resistance statistically calculated by (y = ax − b. Minimum bactericidal concentration’s predication of resistance was given the exponential trend (y = n ex and the predictive coefficient R2 > 0 < 1 are approximately alike. It was assumed that resistant bacteria occurred with a constant rate of antibiotic doses during the whole experimental period. Thus, the number of sensitive bacteria decreases at the same rate as resistant occur following term to the modified predictive model which solved computationally. Conclusion This study assesses the prediction of multi-drug resistance among S. Typhi isolates by applying low cost materials and simple statistical methods suitable for the most frequently used antibiotics as typhoid empirical therapy. Therefore, bacterial surveillance systems should be implemented to present data on the aetiology and current

  19. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  20. Characterizing the surface circulation in Ebro Delta (NW Mediterranean) with HF radar and modeled current data

    Science.gov (United States)

    Lorente, P.; Piedracoba, S.; Sotillo, M. G.; Aznar, R.; Amo-Balandron, A.; Pascual, A.; Soto-Navarro, J.; Alvarez-Fanjul, E.

    2016-11-01

    Quality-controlled current observations from a High Frequency radar (HFR) network deployed in the Ebro River Delta (NW Mediterranean) were combined with outputs from IBI operational ocean forecasting system in order to comprehensively portray the ocean state and its variability during 2014. Accurate HFR data were used as benchmark for a rigorous validation of the Iberia-Biscay-Ireland (IBI) regional system, routinely operated in the frame of the Copernicus Marine Environment Monitoring Service (CMEMS). The analysis of skill metrics and monthly averaged current maps showed that IBI reasonably captured the prevailing dynamic features of the coastal circulation previously observed by the HFR, according to the moderate resemblance found in circulation patterns and the spatial distribution of eddy kinetic energy. The model skill assessment was completed with an exploration of dominant modes of spatiotemporal variability. The EOF analysis confirmed that the modeled surface current field evolved both in space and time according to three significantly dominant modes of variability which accounted for the 49.2% of the total variance, in close agreement with the results obtained for HFR (46.1%). The response of the subtidal surface current field to prevailing wind regime in the study area was examined in terms of induced circulation structures and immediacy of reaction by performing a conditional averaging approach and a time-lagged vector correlation analysis, respectively. This observations-model synergistic strategy has proved to be valid to operationally monitor the complex coastal circulation in Ebro Delta despite the observed model drawbacks in terms of reduced energy content in surface currents and some inaccuracies in the wind-driven low frequency response. This integrated methodology aids to improve the prognostic capabilities of IBI ocean forecasting system and also to facilitate high-stakes decision-making for coastal management in the Ebro River Delta marine

  1. Dilution and Ferrite Number Prediction in Pulsed Current Cladding of Super-Duplex Stainless Steel Using RSM

    Science.gov (United States)

    Eghlimi, Abbas; Shamanian, Morteza; Raeissi, Keyvan

    2013-12-01

    Super-duplex stainless steels have an excellent combination of mechanical properties and corrosion resistance at relatively low temperatures and can be used as a coating to improve the corrosion and wear resistance of low carbon and low alloy steels. Such coatings can be produced using weld cladding. In this study, pulsed current gas tungsten arc cladding process was utilized to deposit super-duplex stainless steel on high strength low alloy steel substrates. In such claddings, it is essential to understand how the dilution affects the composition and ferrite number of super-duplex stainless steel layer in order to be able to estimate its corrosion resistance and mechanical properties. In the current study, the effect of pulsed current gas tungsten arc cladding process parameters on the dilution and ferrite number of super-duplex stainless steel clad layer was investigated by applying response surface methodology. The validity of the proposed models was investigated by using quadratic regression models and analysis of variance. The results showed an inverse relationship between dilution and ferrite number. They also showed that increasing the heat input decreases the ferrite number. The proposed mathematical models are useful for predicting and controlling the ferrite number within an acceptable range for super-duplex stainless steel cladding.

  2. Numerical Studies of Friction Between Metallic Surfaces and of its Dependence on Electric Currents

    Science.gov (United States)

    Meintanis, Evangelos; Marder, Michael

    2009-03-01

    We will present molecular dynamics simulations that explore the frictional mechanisms between clean metallic surfaces. We employ the HOLA molecular dynamics code to run slider-on-block experiments. Both objects are allowed to evolve freely. We recover realistic coefficients of friction and verify the importance of cold-welding and plastic deformations in dry sliding friction. We also find that plastic deformations can significantly affect both objects, despite a difference in hardness. Metallic contacts have significant technological applications in the transmission of electric currents. To explore the effects of the latter to sliding, we had to integrate an electrodynamics solver into the molecular dynamics code. The disparate time scales involved posed a challenge, but we have developed an efficient scheme for such an integration. A limited electrodynamic solver has been implemented and we are currently exploring the effects of currents in the friction and wear of metallic contacts.

  3. Sensitivity of the Antarctic Circumpolar Current transport to surface buoyancy conditions in the North Atlantic

    Science.gov (United States)

    Sun, Shantong; Liu, Jinliang

    2017-10-01

    The sensitivity of the Antarctic Circumpolar Current (ACC) transport to surface buoyancy conditions in the North Atlantic is investigated using a sector configuration of an ocean general circulation model. We find that the sensitivity of the ACC transport is significantly weaker than previous studies. We attribute this difference to the different depth of the simulated Atlantic Meridional Overturning Circulation. Because a fast restoring buoyancy boundary condition is used that strongly constrains the surface buoyancy structure at the Southern Ocean surface, the ACC transport is determined by the isopycnal slope that is coupled to the overturning circulation in the Southern Ocean. By changing the surface buoyancy in the North Atlantic, the shared buoyancy contour between the North Atlantic and the Southern Ocean is varied, and consequently the strength of the overturning circulation is modified. For different depth of the simulated overturning circulation, the response of the ACC transport to changes in the strength of the overturning circulation varies substantially. This is illustrated in two conceptual models based on the residual-mean theory of overturning circulation. Our results imply that the sensitivity of the ACC transport to surface forcing in the North Atlantic could vary substantially in different models depending on the simulated vertical structure of the overturning circulation.

  4. Application of a Saddle-Type Eddy Current Sensor in Steel Ball Surface-Defect Inspection.

    Science.gov (United States)

    Zhang, Huayu; Zhong, Mingming; Xie, Fengqin; Cao, Maoyong

    2017-12-05

    Steel ball surface-defect inspection was performed by using a new saddle-type eddy current sensor (SECS), which included a saddle coil and a signal conditioning circuit. The saddle coil was directly wound on the steel ball's outer bracket in a semi-circumferential direction. Driven by a friction wheel, the test steel ball rotated in a one-dimensional direction, such that the steel ball surface was fully scanned by the SECS. There were two purposes for using the SECS in the steel ball inspection system: one was to reduce the complexity of the unfolding wheel of the surface deployment mechanism, and the other was to reduce the difficulty of sensor processing and installation. Experiments were carried out on bearing steel balls in diameter of 8 mm with three types of representative and typical defects by using the SECS, and the results showed that the inspection system can detect surface defects as small as 0.05 mm in width and 0.1 mm in depth with high-repetition detection accuracy, and the detection efficiency of 5 pcs/s, which meet the requirement for inspecting ISO grade 10 bearing steel balls. The feasibility of detecting steel ball surface defects by SECS was verified.

  5. Influence of an External DC Electric Current on Plasma Cleaning Rate: an Application on the Enlarged Plasma-Surface Theory

    International Nuclear Information System (INIS)

    Xaplanteris, Constantine L.; Filippaki, Eleni D.

    2013-01-01

    During the last decades many researchers have been occupied with other plasma applications apart from the big challenge which the thermonuclear fusion poses. Many experiments have been carried out on the plasma behavior in contact with a solid surface; when the surface material consists of chemical compounds (e.g. oxides of metals), then the plasma chemistry takes place. The present paper contains the final experimental and theoretical work of Plasma Laboratory at “Demokritos , which consists of an elaboration of plasma sheath parameters adapted to experimental conditions, a suitable choice of plasma gases (either H 2 or N 2 ), and an electric potential current enforcement on objects. Additionally, a brief theory is given to explain the results, with a short reference to both boundary phenomena in thermonuclear reactors and low pressure plasma of glow discharges, so as to reveal the similarities and differences of these two cases. An extensive examination of the treated objects by X-ray diffraction method (XRD) gives results in agreement with the theoretical predictions. Using this improvement on plasma restoration system, (a combination of electric current on metallic object into suitable plasma), it is shown that better results can be achieved on the cleaning and conservation of archaeological objects. (plasma technology)

  6. Predicting the potential distribution in China of Euwallacea fornicates (Eichhoff) under current and future climate conditions.

    Science.gov (United States)

    Ge, Xuezhen; Jiang, Chao; Chen, Linghong; Qiu, Shuang; Zhao, Yuxiang; Wang, Tao; Zong, Shixiang

    2017-04-19

    Euwallacea fornicatus (Eichhoff) is an important forest pest that has caused serious damage in America and Vietnam. In 2014, it attacked forests of Acer trialatum in the Yunnan province of China, creating concern in China's Forestry Bureau. We used the CLIMEX model to predict and compare the potential distribution for E. fornicates in China under current (1981-2010) and projected climate conditions (2011-2040) using one scenario (RCP8.5) and one global climate model (GCM), CSIRO-Mk3-6-0. Under both current and future climate conditions, the model predicted E. fornicates to be mainly distributed in the south of China. Comparing distributions under both climate conditions showed that the area of potential distribution was projected to increase (mainly because of an increase in favourable habitat) and shift to the north. Our results help clarify the potential effect of climate change on the range of this forest pest and provide a reference and guide to facilitate its control in China.

  7. Computation of antenna pattern correlation and MIMO performance by means of surface current distribution and spherical wave theory

    Directory of Open Access Journals (Sweden)

    O. Klemp

    2006-01-01

    Full Text Available In order to satisfy the stringent demand for an accurate prediction of MIMO channel capacity and diversity performance in wireless communications, more effective and suitable models that account for real antenna radiation behavior have to be taken into account. One of the main challenges is the accurate modeling of antenna correlation that is directly related to the amount of channel capacity or diversity gain which might be achieved in multi element antenna configurations. Therefore spherical wave theory in electromagnetics is a well known technique to express antenna far fields by means of a compact field expansion with a reduced number of unknowns that was recently applied to derive an analytical approach in the computation of antenna pattern correlation. In this paper we present a novel and efficient computational technique to determine antenna pattern correlation based on the evaluation of the surface current distribution by means of a spherical mode expansion.

  8. Climate-driven range extension of Amphistegina (protista, foraminiferida): models of current and predicted future ranges.

    Science.gov (United States)

    Langer, Martin R; Weinmann, Anna E; Lötters, Stefan; Bernhard, Joan M; Rödder, Dennis

    2013-01-01

    Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year(-1), and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.

  9. Climate-driven range extension of Amphistegina (protista, foraminiferida: models of current and predicted future ranges.

    Directory of Open Access Journals (Sweden)

    Martin R Langer

    Full Text Available Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa at 31°S. To project future species distributions, we applied a species distribution model (SDM based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year(-1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.

  10. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    International Nuclear Information System (INIS)

    Huang, Xiaolong; Wang, Lijun; Deng, Jie; Jia, Shenli; Qin, Kang; Shi, Zongqian

    2016-01-01

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

  11. Eddy current technique for detecting and sizing surface cracks in steel components

    International Nuclear Information System (INIS)

    Cecco, V.S.; Carter, J.R.; Sullivan, S.P.

    1995-01-01

    Cracking has occurred in pressure vessel nozzles and girth welds due to thermal fatigue. Pipe welds, welds in support structures, and welds in reactor vault liner panels in nuclear facilities have failed because of cracks. Cracking can also occur in turbine rotor bore surfaces due to high cycle fatigue. Dye penetrant, magnetic particle and other surface NDT methods are used to detect cracks but cannot be used for depth sizing. Crack depth can be measured with various NDT methods such as ultrasonic time-of-flight diffraction (TOFD), potential drop, and eddy current. The TOFD technique can be difficult to implement on nozzle welds and is best suited for sizing deep cracks (>5 mm). The conventional eddy current method is easy to implement, but crack sizing is normally limited to shallow cracks ( 2 mm) cracks. Eddy current testing (ET) techniques are readily amenable to remote/automatic inspections. These new probes could augment present magnetic particle (MT) and dye penetrant (PT) testing through provision of reliable defect depth information. Reliable crack sizing permits identification of critical cracks for plant life extension and licensing purposes. In addition, performing PT and MT generates low level radioactive waste in some inspection applications in nuclear facilities. Replacing these techniques with ET for some components will eliminate some of this radioactive waste. (author)

  12. Near-Surface Residual Stress-Profiling with High Frequency Eddy Current Conductivity Measurement

    Science.gov (United States)

    Hillmann, S.; Heuer, H.; Baron, H.-U.; Bamberg, J.; Yashan, A.; Meyendorf, N.

    2009-03-01

    The lifetime of aero engine components can be extended by applying an additional strain to the material. Typical aero engine-alloys like Nickel-Base superalloys or Titanium alloys can be surface-treated by use of shot peening to induce the compressive strain near the surface. However, in order to use the additional life for critical aero engine components, a quantitative determination of strain gradients near the surface has to be carried out periodically. We propose to measure the depth-profile of residual stresses non-destructively by use of high frequency eddy current techniques. This paper presents results obtained with an experimental set-up based on a high precision impedance analyzer. Test samples prepared from IN718 by shot peening of different intensities can be easily distinguished. By sweeping the frequency from 100 kHz up to 100 MHz a depth profile for the electrical conductivity from 50 μm to 500 μm can be obtained. The measured conductivity profile is a resultant from residual stresses, cold work, surface roughness and the texture of the material. In addition, first results for strain profiling obtained with industry applicable NDE instrument will be presented.

  13. Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

    Science.gov (United States)

    Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

    2011-07-01

    Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Noether Current of the Surface Term of Einstein-Hilbert Action, Virasoro Algebra, and Entropy

    Directory of Open Access Journals (Sweden)

    Bibhas Ranjan Majhi

    2013-01-01

    Full Text Available A derivation of Noether current from the surface term of Einstein-Hilbert action is given. We show that the corresponding charge, calculated on the horizon, is related to the Bekenstein-Hawking entropy. Also using the charge, the same entropy is found based on the Virasoro algebra and Cardy formula approach. In this approach, the relevant diffeomorphisms are found by imposing a very simple physical argument: diffeomorphisms keep the horizon structure invariant. This complements similar earlier results (Majhi and Padmanabhan (2012 (arXiv:1204.1422 obtained from York-Gibbons-Hawking surface term. Finally we discuss the technical simplicities and improvements over the earlier attempts and also various important physical implications.

  15. High resolution laser beam induced current focusing for photoactive surface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Lorenzo, C. [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Cadiz, Apartado de Correos 40, 11510 Puerto Real, Cadiz (Spain)]. E-mail: concha.fernandez@uca.es; Poce-Fatou, J.A. [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Cadiz, Apartado de Correos 40, 11510 Puerto Real, Cadiz (Spain); Alcantara, R. [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Cadiz, Apartado de Correos 40, 11510 Puerto Real, Cadiz (Spain); Navas, J. [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Cadiz, Apartado de Correos 40, 11510 Puerto Real, Cadiz (Spain); Martin, J. [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Cadiz, Apartado de Correos 40, 11510 Puerto Real, Cadiz (Spain)

    2006-12-15

    The micro-characterization of several surface properties of the solar cells can be accomplished using high-resolution laser beam induced current images. For obtaining these images, a very precise laser beam focusing on the photoactive surface is required. For this purpose, a methodology for obtaining the best focalization associated to the maximum of a peak curve has been developed. In this paper, a data set, obtained from the inner photoconversion properties of the system, has been evaluated with three different numerical analysis techniques: (a) derivative (b) length and (c) Fourier Transform, in order to get the finest possible peak distribution. Then, an amount of 13 analytical peak curves using the Levenberg Marquardt algorithm to find the best curve that adjusts the data distribution have been analyzed.

  16. The ISMAR high frequency coastal radar network: Monitoring surface currents for management of marine resources

    DEFF Research Database (Denmark)

    Carlson, Daniel Frazier

    2015-01-01

    The Institute of Marine Sciences (ISMAR) of the National Research Council of Italy (CNR) established a High Frequency (HF) Coastal Radar Network for the measurement of the velocity of surface currents in coastal seas. The network consists of four HF radar systems located on the coast of the Gargano...... Promontory (Southern Adriatic, Italy). The network has been operational since May 2013 and covers an area of approximately 1700 square kilometers in the Gulf of Manfredonia. Quality Assessment (QA) procedures are applied for the systems deployment and maintenance and Quality Control (QC) procedures...

  17. On The Accuracy Of Current Mean Sea Surface Models For The Use With Goce Data

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Rio, M. H.

    2011-01-01

    The mean sea surface (MSS) is a fundamental parameter in geodesy and physical oceanography and knowledge about the error on the MSS is fundamental for the interpretation of GOCE geoid model for the study of large scale ocean circulation. The MSS is the sum of the geoid height G and the temporal...... mean of the ocean mean dynamic topography (MDT) like MSS = G + MDT, where the MDT is the quantity bridging the geoid and the MSS and the quantity constraining large scale ocean circulation. In order to evaluate the accurate of satellite derived ocean currents from the difference between the MSS...

  18. Control and Calibration of a Staubli RX130 Robotic Arm for Construction of Surface Current Coils

    Science.gov (United States)

    Vanmeter, Patrick; Crawford, Christopher; Guler, Emre; Fugal, Mario; Irvin, Bradley

    2013-10-01

    Precision low energy neutron experiments require extremely uniform magnetic fields for manipulating the neutron spin. Such fields can be generated with surface current coils-precision 3-dimensional printed circuits. We are developing a facility to etch out these circuits on copper-plated curved forms using a high-speed spindle attached to the end-effector of a Staubli RX130 six-axis robotic arm. We describe our mathematical model of the robotic links and the software system we designed to control the motion of the arm and to prevent collisions during actuations. We developed a calibration procedure to achieve accuracy of 30 microns in the position of drill.

  19. Analytical Modeling Of The Steinmetz Coefficient For Single-Phase Transformer Eddy Current Loss Prediction

    Directory of Open Access Journals (Sweden)

    T. Aly Saandy

    2015-08-01

    Full Text Available Abstract This article presents to an analytical calculation methodology of the Steinmetz coefficient applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active power consumed by the core is expressed analytically in function of the electrical parameters as resistivity and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The required coefficient is identified from the empirical Steinmetz data based on the experimented active power expression. To verify the relevance of the model validations both by simulations with two in two different frequencies and measurements were carried out. The obtained results are in good agreement with the theoretical approach and the practical results.

  20. Oral drug absorption in pediatrics: the intestinal wall, its developmental changes and current tools for predictions.

    Science.gov (United States)

    Nicolas, Jean-Marie; Bouzom, François; Hugues, Chanteux; Ungell, Anna-Lena

    2017-04-01

    The dissolution, intestinal absorption and presystemic metabolism of a drug depend on its physicochemical characteristics but also on numerous physiological (e.g. gastrointestinal pH, volume, transit time, morphology) and biochemical factors (e.g. luminal enzymes and flora, intestinal wall enzymes and transporters). Over the past decade, evidence has accumulated indicating that these factors may differ in children and adults resulting in age-related changes in drug exposure and drug response. Thus, drug dosage may require adjustment for the pediatric population to ensure the desired therapeutic outcome and to avoid side-effects. Although tremendous progress has been made in understanding the effects of age on intestinal physiology and function, significant knowledge gaps remain. Studying and predicting pharmacokinetics in pediatric patients remains challenging due to ethical concerns associated with clinical trials in this vulnerable population, and because of the paucity of predictive in vitro and in vivo animal assays. This review details the current knowledge related to developmental changes determining intestinal drug absorption and pre-systemic metabolism. Supporting experimental approaches as well as physiologically based pharmacokinetic modeling are also discussed together with their limitations and challenges. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Solar Atmosphere to Earth's Surface: Long Lead Time dB/dt Predictions with the Space Weather Modeling Framework

    Science.gov (United States)

    Welling, D. T.; Manchester, W.; Savani, N.; Sokolov, I.; van der Holst, B.; Jin, M.; Toth, G.; Liemohn, M. W.; Gombosi, T. I.

    2017-12-01

    The future of space weather prediction depends on the community's ability to predict L1 values from observations of the solar atmosphere, which can yield hours of lead time. While both empirical and physics-based L1 forecast methods exist, it is not yet known if this nascent capability can translate to skilled dB/dt forecasts at the Earth's surface. This paper shows results for the first forecast-quality, solar-atmosphere-to-Earth's-surface dB/dt predictions. Two methods are used to predict solar wind and IMF conditions at L1 for several real-world coronal mass ejection events. The first method is an empirical and observationally based system to estimate the plasma characteristics. The magnetic field predictions are based on the Bz4Cast system which assumes that the CME has a cylindrical flux rope geometry locally around Earth's trajectory. The remaining plasma parameters of density, temperature and velocity are estimated from white-light coronagraphs via a variety of triangulation methods and forward based modelling. The second is a first-principles-based approach that combines the Eruptive Event Generator using Gibson-Low configuration (EEGGL) model with the Alfven Wave Solar Model (AWSoM). EEGGL specifies parameters for the Gibson-Low flux rope such that it erupts, driving a CME in the coronal model that reproduces coronagraph observations and propagates to 1AU. The resulting solar wind predictions are used to drive the operational Space Weather Modeling Framework (SWMF) for geospace. Following the configuration used by NOAA's Space Weather Prediction Center, this setup couples the BATS-R-US global magnetohydromagnetic model to the Rice Convection Model (RCM) ring current model and a height-integrated ionosphere electrodynamics model. The long lead time predictions of dB/dt are compared to model results that are driven by L1 solar wind observations. Both are compared to real-world observations from surface magnetometers at a variety of geomagnetic latitudes

  2. Invasive alien plants and water resources in South Africa: current understanding, predictive ability and research challenges

    CSIR Research Space (South Africa)

    Gorgens, AHM

    2004-01-01

    Full Text Available from which a detailed understanding of biophysical processes can be developed; applied or predictive research from which an understanding of processes can be scaled up to predict generic outcomes; integrative research where a predictive understanding...

  3. Application of current and future satellite missions to hydrologic prediction in transboundary rivers

    Science.gov (United States)

    Biancamaria, S.; Clark, E.; Lettenmaier, D. P.

    2010-12-01

    More than 256 major global river basins, which cover about 45% of the continental land surface, are shared among two or more countries. The flow of such a large part of the global runoff across international boundaries has led to tension in many cases between upstream and downstream riparian countries. Among many examples, this is the case of the Ganges and the Brahmaputra Rivers, which cross the boundary between India and Bangladesh. Hydrological data (river discharge, reservoir storage) are viewed as sensitive by India (the upstream country) and are therefore not shared with Bangladesh, which can only monitor river discharge and water depth at the international border crossing. These measurements only allow forecasting of floods in the interior and southern portions of the country two to three days in advance. These forecasts are not long enough either for agricultural water management purposes (for which knowledge of upstream reservoir storage is essential) or for disaster preparedness purposes. Satellite observations of river spatial extent, surface slope, reservoir area and surface elevation have the potential to make tremendous changes in management of water within the basins. In this study, we examine the use of currently available satellite measurements (in India) and in-situ measurements in Bangladesh to increase forecast lead time in the Ganges and Brahmaputra Rivers. Using nadir altimeters, we find that it is possible to forecast the discharge of the Ganges River at the Bangladesh border with lead time 3 days and mean absolute error of around 25%. On the Ganges River, 2-day forecasts are possible with a mean absolute error of around 20%. When combined with optical/infra-red MODIS images, it is possible to map water elevations along the river and its floodplain upstream of the boundary, and to compute water storage. However, the high frequency of clouds in this region results in relatively large errors in the water mask. Due to the nadir altimeter

  4. The artificial object detection and current velocity measurement using SAR ocean surface images

    Science.gov (United States)

    Alpatov, Boris; Strotov, Valery; Ershov, Maksim; Muraviev, Vadim; Feldman, Alexander; Smirnov, Sergey

    2017-10-01

    Due to the fact that water surface covers wide areas, remote sensing is the most appropriate way of getting information about ocean environment for vessel tracking, security purposes, ecological studies and others. Processing of synthetic aperture radar (SAR) images is extensively used for control and monitoring of the ocean surface. Image data can be acquired from Earth observation satellites, such as TerraSAR-X, ERS, and COSMO-SkyMed. Thus, SAR image processing can be used to solve many problems arising in this field of research. This paper discusses some of them including ship detection, oil pollution control and ocean currents mapping. Due to complexity of the problem several specialized algorithm are necessary to develop. The oil spill detection algorithm consists of the following main steps: image preprocessing, detection of dark areas, parameter extraction and classification. The ship detection algorithm consists of the following main steps: prescreening, land masking, image segmentation combined with parameter measurement, ship orientation estimation and object discrimination. The proposed approach to ocean currents mapping is based on Doppler's law. The results of computer modeling on real SAR images are presented. Based on these results it is concluded that the proposed approaches can be used in maritime applications.

  5. Multifrequency eddy current examination for surface defects detection of hot steel products

    International Nuclear Information System (INIS)

    Hiroshima, Tatsuo; Sakamoto, Takahide; Takahashi, Akio; Miyata, Kenichi.

    1985-01-01

    Multifrequency eddy current testing method using probe coils has been studied for surface defects detection in hot steel products at high temperature over the magnetic Curie point. The conventional signal processing method is not available for suppression of an undesirable signal caused by lift-off variation or unevenness in inspected surfaces, because the undesirable signal pattern is similar to a defect signal pattern. In order to suppress the undesirable signal a new dual frequency signal processing method using three phase rotators has been developed, and was applied to several hot steel inspections. The results are as follows. 1. In the rotating eddy current machine for hot steel rods, the lift-off variation signal caused by a wobble of rods or the difference between rotating center and pass center of rods can be suppressed. A long seam or crack whose depth is more than 0.5mm can be detected. 2. In the hot inspection for continuously cast slabs, the signal caused by oscillation mark whose depth is under 1 mm can be suppressed. A fine transversal crack whose depth is 2 mm can be detected. 3. In the hot inspection for round billets, the lift-off variation signal caused by oval shape can be eliminated, and a crack which is deeper than 1.5 mm can be clearly detected. The detectability of defects can be improved by the analysis of dual frequency signal pattern. (author)

  6. Fault type predictions from stress distributions on planetary surfaces - Importance of fault initiation depth

    Science.gov (United States)

    Golombek, M. P.

    1985-01-01

    The prediction of fault type on planetary surfaces from model stresses calculated at depth is discussed. These fault-type predictions yield different faults than those predicted using the surface criteria commonly employed in geophysical models. For elastic-plate flexure models of mascon loading on the moon, stresses calculated at the surface predict the occurrence of strike-slip faulting at the radial distance where grabens are found. Normal faults bounding lunar grabens and thrust faults responsible for wrinkle ridges are analyzed. It is found that the former initiate at the mechanical discontinuity that separates the breccia of the megaregolith from in situ fractured rock and that the latter initiate at the mechanical discontinuity between basalt layers and the underlying basin floor. The difference between elastic constants for the outer few kilometers of brecciated megaregolith and the underlying lunar lithosphere are evaluated. Superposing nonisotropic stresses resulting from the weight of overburden to the depth of the relevant mechanical discontinuity yield stresses that predict wrinkle ridges in the basin centers and grabens outside the basin margin, and eliminate the predicted zone of strike-slip faults.

  7. Open-Delta Three-Phase Inverter Current Control Using Predictive Control For PV System Connected To The Grid

    OpenAIRE

    ABBASİ, Zohre; FESHKİ FARAHANİ, Hassan

    2015-01-01

    Abstract. Predictive control method has advantages such as simple structure, functional and follow the simple mathematical. In this paper, a new method is provided for controlling the open-Delta three-phase inverter . Model-based predictive control system is used for controlling the current of a open-Delta three-phase inverter, which is in the process of converting the photovoltaic energy conversion plays a three-phase network. The controller at any time, the next period current are estimated...

  8. Surface alloying of aluminum with molybdenum by high-current pulsed electron beam

    Science.gov (United States)

    Xia, Han; Zhang, Conglin; Lv, Peng; Cai, Jie; Jin, Yunxue; Guan, Qingfeng

    2018-02-01

    The surface alloying of pre-coated molybdenum (Mo) film on aluminum (Al) substrate by high-current pulsed electron beam (HCPEB) was investigated. The microstructure and phase analysis were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that Mo particles were dissolved into Al matrix to form alloying layer, which was composed of Mo, Al and acicular or equiaxed Al5Mo phases after surface alloying. Meanwhile, various structure defects such as dislocation loops, high-density dislocations and dislocation walls were observed in the alloying surface. The corrosion resistance was tested by using potentiodynamic polarization curves and electrochemical impedance spectra (EIS). Electrochemical results indicate that all the alloying samples had better corrosion resistance in 3.5 wt% NaCl solution compared to initial sample. The excellent corrosion resistance is mainly attributed to the combined effect of the structure defects and the addition of Mo element to form a more stable passive film.

  9. A Flexible Arrayed Eddy Current Sensor for Inspection of Hollow Axle Inner Surfaces

    Directory of Open Access Journals (Sweden)

    Zhenguo Sun

    2016-06-01

    Full Text Available A reliable and accurate inspection of the hollow axle inner surface is important for the safe operation of high-speed trains. In order to improve the reliability of the inspection, a flexible arrayed eddy current sensor for non-destructive testing of the hollow axle inner surface was designed, fabricated and characterized. The sensor, consisting of two excitation traces and 28 sensing traces, was developed by using the flexible printed circuit board (FPCB technique to conform the geometric features of the inner surfaces of the hollow axles. The main innovative aspect of the sensor was the new arrangement of excitation/sensing traces to achieve a differential configuration. Finite element model was established to analyze sensor responses and to determine the optimal excitation frequency. Experimental validations were conducted on a specimen with several artificial defects. Results from experiments and simulations were consistent with each other, with the maximum relative error less than 4%. Both results proved that the sensor was capable of detecting longitudinal and transverse defects with the depth of 0.5 mm under the optimal excitation frequency of 0.9 MHz.

  10. High sea surface temperatures driven by a strengthening current reduce foraging success by penguins

    Science.gov (United States)

    Carroll, G.; Everett, J. D.; Harcourt, R.; Slip, D.; Jonsen, I.

    2016-02-01

    The world's oceans are undergoing rapid, regionally specific warming. Strengthening western boundary currents play a significant role in this phenomenon, with sea surface temperatures (SST) in their paths rising faster than the global average. To understand how dynamic oceanography influences food availability in these ocean warming "hotspots", we use a novel prey capture signature derived from accelerometry to understand how the warm East Australian Current shapes foraging success by a meso-predator, the little penguin. This seabird feeds on low-trophic level species that are sensitive to environmental change. We found that in 2012, prey capture success by penguins was high when SST was low relative to the long-term mean. In 2013 prey capture success was low, coincident with an unusually strong penetration of warm water. Overall there was an optimal temperature range for prey capture around 19-21oC, with lower success at both lower and higher temperatures, mirroring published relationships between commercial sardine catch and SST. Spatially, higher SSTs corresponded to a lower probability of penguins using an area, and lower prey capture success. These links between high SST and reduced prey capture success by penguins suggest negative implications for future resource availability in a system dominated by a strengthening western boundary current.

  11. Development of a Magnetostrictive FeNi Coated Surface Acoustic Wave Current Sensor

    Directory of Open Access Journals (Sweden)

    Jie Tong

    2017-07-01

    Full Text Available A magnetostrictive FeNi-coated surface acoustic wave (SAW-based current sensor was proposed in this work. The weak remanence and hysteresis effect of the FeNi itself contributes to suppress the asymmetry in sensor response at increasing and decreasing current. The sensor response was simulated by solving the coupled electromechanical field equation in layered structure considering the magnetostrictive effect and an approach of effective dielectric constant. The effects from the aspect ratio and thickness of the FeNi film on sensor response were analyzed to determine the optimal design parameters. Differential oscillation structure was used to form the sensor, in which, the FeNi thin film was deposited along the SAW propagation of the sensor chip by using RF magnetron sputtering. The magnetostrictive effect of the FeNi coating induced by the magnetic loading generates the perturbation in SAW velocity, and corresponding oscillation frequency. High sensitivity of 10.7 KHz/A, good linearity and repeatability, lower hysteresis error of 0.97% were obtained from the developed prototype 150 MHz SAW FeNi coated current sensor.

  12. 2D instabilities of surface gravity waves on a linear shear current

    Science.gov (United States)

    Francius, Marc; Kharif, Christian

    2016-04-01

    Periodic 2D surface water waves propagating steadily on a rotational current have been studied by many authors (see [1] and references therein). Although the recent important theoretical developments have confirmed that periodic waves can exist over flows with arbitrary vorticity, their stability and their nonlinear evolution have not been much studied extensively so far. In fact, even in the rather simple case of uniform vorticity (linear shear), few papers have been published on the effect of a vertical shear current on the side-band instability of a uniform wave train over finite depth. In most of these studies [2-5], asymptotic expansions and multiple scales method have been used to obtain envelope evolution equations, which allow eventually to formulate a condition of (linear) instability to long modulational perturbations. It is noted here that this instability is often referred in the literature as the Benjamin-Feir or modulational instability. In the present study, we consider the linear stability of finite amplitude two-dimensional, periodic water waves propagating steadily on the free surface of a fluid with constant vorticity and finite depth. First, the steadily propagating surface waves are computed with steepness up to very close to the highest, using a Fourier series expansions and a collocation method, which constitutes a simple extension of Fenton's method [6] to the cases with a linear shear current. Then, the linear stability of these permanent waves to infinitesimal 2D perturbations is developed from the fully nonlinear equations in the framework of normal modes analysis. This linear stability analysis is an extension of [7] to the case of waves in the presence of a linear shear current and permits the determination of the dominant instability as a function of depth and vorticity for a given steepness. The numerical results are used to assess the accuracy of the vor-NLS equation derived in [5] for the characteristics of modulational

  13. Novel structures of oxygen adsorbed on a Zr(0001) surface predicted from first principles

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Bo [State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130012 (China); Beijing computational science research center, Beijing,100084 (China); Wang, Jianyun [State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130012 (China); Lv, Jian [State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130012 (China); College of Materials Science and Engineering, Jilin University, Changchun, 130012 (China); Gao, Xingyu [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing, 100088 (China); CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088 (China); Zhao, Yafan [CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088 (China); Wang, Yanchao, E-mail: wyc@calypso.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130012 (China); Beijing computational science research center, Beijing,100084 (China); College of Materials Science and Engineering, Jilin University, Changchun, 130012 (China); Song, Haifeng, E-mail: song_haifeng@iapcm.ac.cn [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing, 100088 (China); CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088 (China); Ma, Yanming [State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130012 (China); Beijing computational science research center, Beijing,100084 (China)

    2017-01-30

    Highlights: • Two stable structures of O adsorbed on a Zr(0001) surface are predicted with SLAM. • A stable structure of O adsorbed on a Zr(0001) surface is proposed with MLAM. • The calculated work function change is agreement with experimental value. - Abstract: The structures of O atoms adsorbed on a metal surface influence the metal properties significantly. Thus, studying O chemisorption on a Zr surface is of great interest. We investigated O adsorption on a Zr(0001) surface using our newly developed structure-searching method combined with first-principles calculations. A novel structural prototype with a unique combination of surface face-centered cubic (SFCC) and surface hexagonal close-packed (SHCP) O adsorption sites was predicted using a single-layer adsorption model (SLAM) for a 0.5 and 1.0 monolayer (ML) O coverage. First-principles calculations based on the SLAM revealed that the new predicted structures are energetically favorable compared with the well-known SFCC structures for a low O coverage (0.5 and 1.0 ML). Furthermore, on basis of our predicted SFCC + SHCP structures, a new structure within multi-layer adsorption model (MLAM) was proposed to be more stable at the O coverage of 1.0 ML, in which adsorbed O atoms occupy the SFCC + SHCP sites and the substitutional octahedral sites. The calculated work functions indicate that the SFCC + SHCP configuration has the lowest work function of all known structures at an O coverage of 0.5 ML within the SLAM, which agrees with the experimental trend of work function with variation in O coverage.

  14. Influence of the surface drag coefficient (young waves) on the current structure of the Berre lagoon

    Science.gov (United States)

    Alekseenko, Elena; Roux, Bernard; Kharif, Christian; Sukhinov, Alexander; Kotarba, Richard; Fougere, Dominique; Chen, Paul Gang

    2013-04-01

    Due to the shallowness, currents and hydrodynamics of Berre lagoon (South of France) are closely conditioned by the bottom topography, and wind affects the entire water column, as for many other Mediterranean lagoons (Perez-Ruzafa, 2011). Wind stress, which is caused by moving atmospheric disturbance, is known to have a major influence in lagoon water circulation. According to the numerical simulation for the main directions of the wind: N-NW, S-SE and W (wind speed of 80 km/h) it is observed that the current is maximal alongshore in the wind direction; the bottom nearshore current being larger in shallower area. This fact is coherent with fundamental principle of wind-driven flows in closed or partially closed basins which states that in shallow water the dominant force balance is between surface wind stress and bottom friction, yielding a current in the direction of the wind (Mathieu et al, 2002, Hunter and Hearn, 1987; Hearn and Hunter,1990). A uniform wind stress applied at the surface of a basin of variable depth sets up a circulation pattern characterized by relatively strong barotropic coastal currents in the direction of the wind, with return flow occurring over the deeper regions (Csanady, 1967; Csanady, 1971). One of the key parameters characterizing the wind stress formulation is a surface drag coefficient (Cds). Thus, an effect of a surface drag coefficient, in the range 0.0016 - 0.0032, will be analyzed in this work. The value of surface drag coefficient Cds = 0.0016 used in our previous studies (Alekseenko et al., 2012), would correspond to mature waves (open sea). But, in the case of semi-closed lagoonal ecosystem, it would be more appropriate to consider "young waves" mechanism. A dependency of this coefficient in terms of the wind speed is given by Young (1999) in both cases of mature waves and young waves. For "young waves" generated at a wind speed of 80 km/h, Cds = 0.0032. So, the influence of Cds on the vertical profile of the velocity in the

  15. Bell's palsy in children: Current treatment patterns in Australia and New Zealand. A PREDICT study.

    Science.gov (United States)

    Babl, Franz E; Gardiner, Kaya K; Kochar, Amit; Wilson, Catherine L; George, Shane A; Zhang, Michael; Furyk, Jeremy; Thosar, Deepali; Cheek, John A; Krieser, David; Rao, Arjun S; Borland, Meredith L; Cheng, Nicholas; Phillips, Natalie T; Sinn, Kam K; Neutze, Jocelyn M; Dalziel, Stuart R

    2017-04-01

    The aetiology and clinical course of Bell's palsy may be different in paediatric and adult patients. There is no randomised placebo controlled trial (RCT) to show effectiveness of prednisolone for Bell's palsy in children. The aim of the study was to assess current practice in paediatric Bell's palsy in Australia and New Zealand Emergency Departments (ED) and determine the feasibility of conducting a multicentre RCT within the Paediatric Research in Emergency Departments International Collaborative (PREDICT). A retrospective analysis of ED medical records of children less than 18 years diagnosed with Bell's palsy between 1 January, 2012 and 31 December, 2013 was performed. Potential participants were identified from ED information systems using Bell's palsy related search terms. Repeat presentations during the same illness were excluded but relapses were not. Data on presentation, diagnosis and management were entered into an online data base (REDCap). Three hundred and twenty-three presentations were included from 14 PREDICT sites. Mean age at presentation was 9.0 (SD 5.0) years with 184 (57.0%) females. Most (238, 73.7%) presented to ED within 72 h of symptoms, 168 (52.0%) had seen a doctor prior. In ED, 218 (67.5%) were treated with steroids. Prednisolone was usually prescribed for 9 days at around 1 mg/kg/day, with tapering in 35.7%. Treatment of Bell's palsy in children presenting to Australasian EDs is varied. Prednisolone is commonly used in Australasian EDs, despite lack of high-level paediatric evidence. The study findings confirm the feasibility of an RCT of prednisolone for Bell's palsy in children. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  16. Land surface contribution to climate predictability: the long way from early evidence to improved forecast skill

    Science.gov (United States)

    Douville, Hervé

    2013-04-01

    Seasonal forecasts performance over most land areas remains relatively weak, particularly in the mid-latitudes where the interannual ocean variability has a lesser influence than in the tropics. Yet, many observational and numerical studies suggest that there is a fraction of predictability that is still untapped over land at the monthly to seasonal time scales, due to both local and remote land surface effects. Soil moisture and snow mass anomalies may have a strong signature in the land surface energy budget and thereby influence not only surface temperature, but also precipitation through changes in surface evaporation and/or moisture convergence. Land surface anomalies may also trigger planetary waves that can have remote effects on seasonal mean climate. This talk will first illustrate some potential land surface impacts on climate predictability using both statistical and numerical evidence. Then, the limitations of such studies and the practical difficulties for taking advantage of the land surface memory will be presented, as well as on-going efforts for adressing these issues at both European (i.e., SPECS) and international (i.e., GLACE) levels.

  17. Evaluation of a Regression Prediction Model for Surface Roughness of Wood-Polyethylene Composite (wpc)

    Science.gov (United States)

    Shi, Wenyong; Ma, Yan; Yang, Chunmei; Jiang, Bin; Li, Zhe

    Milling processing is an important way to obtain wood-polyethylene composite (WPC) end products. In order to improve the processing efficiency and surface quality of WPC and meet the practical application requirements, this paper focussed on morphology and roughness of the WPC-milled surface and studied surface quality changes under different cutting parameters and milling methods through multi-parameters milling experiments. The milling surface morphology and roughness of WPC were analyzed and measured during cut-in, cutting and cut-out sections. It also revealed the affect rule of different cutting parameters and milling methods on milled surface morphology and roughness. The results show that the milling surface roughness of WPC products with wood powder content of 70% is significantly larger than the one whose wood powder content is 60%, and defects such as holes are also relatively more. Finally, a surface roughness prediction model was established based on the mathematical regression method and its multi-factor simulation was carried out. A comparative analysis of predictive and experimental values was performed to verify the reliability of the model. It could also provide theoretical guidance and technical guarantee for high processing quality of WPC milling and cutting.

  18. Oxidative stress prediction: A preliminary approach using a response surface based technique.

    Science.gov (United States)

    Sierra, M; Bragg-Gonzalo, L; Grasa, J; Muñoz, M J; González, D; Miana-Mena, F J

    2018-02-01

    A response surface was built to predict the lipid peroxidation level, generated in an iron-ascorbate in vitro model, of any organ, which is correlated with the oxidative stress injury in biological membranes. Oxidative stress studies are numerous, usually performed on laboratory animals. However, ethical concerns require validated methods to reduce the use of laboratory animals. The response surface described here is a validated method to replace animals. Tissue samples of rabbit liver, kidney, heart, skeletal muscle and brain were oxidized with different concentrations of FeCl 3 (0.1 to 8mM) and ascorbate (0.1mM), during different periods of time (0 to 90min) at 37°C. Experimental data obtained, with lipid content and antioxidant activity of each organ, allowed constructing a multidimensional surface capable of predicting, by interpolation, the lipid peroxidation level of any organ defined by its antioxidant activity and fat content, when exposed to different oxidant conditions. To check the predictive potential of the technique, two more experiments were carried out. First, in vitro oxidation data from lung tissue were collected. Second, the antioxidant capacity of kidney homogenates was modified by adding melatonin. Then, the response surface generated could predict lipid peroxidation levels produced in these new situations. The potential of this technique could be reinforced using collaborative databases to reduce the number of animals in experimental procedures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Macrobenthic species response surfaces along estuarine gradients: prediction by logistic regression

    NARCIS (Netherlands)

    Ysebaert, T.; Meire, P.; Herman, P.M.J.; Verbeek, H.

    2002-01-01

    This study aims at contributing to the development of statistical models to predict macrobenthic species response to environmental conditions in estuarine ecosystems. Ecological response surfaces are derived for 10 estuarine macrobenthic species. Logistic regression is applied on a large data set,

  20. Finite Element Simulation of Shot Peening: Prediction of Residual Stresses and Surface Roughness

    Science.gov (United States)

    Gariépy, Alexandre; Perron, Claude; Bocher, Philippe; Lévesque, Martin

    Shot peening is a surface treatment that consists of bombarding a ductile surface with numerous small and hard particles. Each impact creates localized plastic strains that permanently stretch the surface. Since the underlying material constrains this stretching, compressive residual stresses are generated near the surface. This process is commonly used in the automotive and aerospace industries to improve fatigue life. Finite element analyses can be used to predict residual stress profiles and surface roughness created by shot peening. This study investigates further the parameters and capabilities of a random impact model by evaluating the representative volume element and the calculated stress distribution. Using an isotropic-kinematic hardening constitutive law to describe the behaviour of AA2024-T351 aluminium alloy, promising results were achieved in terms of residual stresses.

  1. Backtracking drifting objects using surface currents from high-frequency (HF) radar technology

    Science.gov (United States)

    Abascal, Ana Julia; Castanedo, Sonia; Fernández, Vicente; Medina, Raúl

    2012-07-01

    In this work, the benefits of high-frequency (HF) radar ocean observation technology for backtracking drifting objects are analysed. The HF radar performance is evaluated by comparison of trajectories between drifter buoys versus numerical simulations using a Lagrangian trajectory model. High-resolution currents measured by a coastal HF radar network combined with atmospheric fields provided by numerical models are used to backtrack the trajectory of two dataset of surface-drifting buoys: group I (with drogue) and group II (without drogue). A methodology based on optimization methods is applied to estimate the uncertainty in the trajectory simulations and to optimize the search area of the backtracked positions. The results show that, to backtrack the trajectory of the buoys in group II, both currents and wind fields were required. However, wind fields could be practically discarded when simulating the trajectories of group I. In this case, the optimal backtracked trajectories were obtained using only HF radar currents as forcing. Based on the radar availability data, two periods ranging between 8 and 10 h were selected to backtrack the buoy trajectories. The root mean squared error (RMSE) was found to be 1.01 km for group I and 0.82 km for group II. Taking into account these values, a search area was calculated using circles of RMSE radii, obtaining 3.2 and 2.11 km2 for groups I and II, respectively. These results show the positive contribution of HF radar currents for backtracking drifting objects and demonstrate that these data combined with atmospheric models are of value to perform backtracking analysis of drifting objects.

  2. LIGSITEcsc: predicting ligand binding sites using the Connolly surface and degree of conservation

    Directory of Open Access Journals (Sweden)

    Schroeder Michael

    2006-09-01

    Full Text Available Abstract Background Identifying pockets on protein surfaces is of great importance for many structure-based drug design applications and protein-ligand docking algorithms. Over the last ten years, many geometric methods for the prediction of ligand-binding sites have been developed. Results We present LIGSITEcsc, an extension and implementation of the LIGSITE algorithm. LIGSITEcsc is based on the notion of surface-solvent-surface events and the degree of conservation of the involved surface residues. We compare our algorithm to four other approaches, LIGSITE, CAST, PASS, and SURFNET, and evaluate all on a dataset of 48 unbound/bound structures and 210 bound-structures. LIGSITEcsc performs slightly better than the other tools and achieves a success rate of 71% and 75%, respectively. Conclusion The use of the Connolly surface leads to slight improvements, the prediction re-ranking by conservation to significant improvements of the binding site predictions. A web server for LIGSITEcsc and its source code is available at scoppi.biotec.tu-dresden.de/pocket.

  3. Surface Complexation Modeling in Variable Charge Soils: Prediction of Cadmium Adsorption

    Directory of Open Access Journals (Sweden)

    Giuliano Marchi

    2015-10-01

    Full Text Available ABSTRACT Intrinsic equilibrium constants for 22 representative Brazilian Oxisols were estimated from a cadmium adsorption experiment. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. Intrinsic equilibrium constants were optimized by FITEQL and by hand calculation using Visual MINTEQ in sweep mode, and Excel spreadsheets. Data from both models were incorporated into Visual MINTEQ. Constants estimated by FITEQL and incorporated in Visual MINTEQ software failed to predict observed data accurately. However, FITEQL raw output data rendered good results when predicted values were directly compared with observed values, instead of incorporating the estimated constants into Visual MINTEQ. Intrinsic equilibrium constants optimized by hand calculation and incorporated in Visual MINTEQ reliably predicted Cd adsorption reactions on soil surfaces under changing environmental conditions.

  4. Marine oil degrading bacteria related to oil inputs and surface currents in the western Caribbean Sea

    International Nuclear Information System (INIS)

    Lizarraga-Partida, M.L.; Vicuna, F.B.I.; Chang, I.W.

    1990-01-01

    The distribution of oil degrading bacteria (ODB) and its ratios to viable heterotrophic bacteria (CFU) and direct counts (AODC) were examined in relation to the surface currents of the western Caribbean Sea. High ODB/CFU and ODB/AODC ratios were found, suggesting that chronic sources of hydrocarbons in the region may have a larger impact than those in the southern Gulf of Mexico, where previous studies have been performed. It was concluded that, in western Caribbean waters, the distribution of oil degrading bacteria, or its ratios to CFU or AODC, could be useful indicators of chronic oil inputs originating at the east of the Caribbean Sea, as well as their motions afterwards. (author)

  5. Prediction of the surface roughness of AA6082 flow-formed tubes by design of experiments

    International Nuclear Information System (INIS)

    Srinivasulu, M.; Komaraiah, M.; Rao, C. S. Krishna Prasada

    2013-01-01

    Flow forming is a modern, chipless metal forming process that is employed for the production of thin-walled seamless tubes. Experiments are conducted on AA6082 alloy pre-forms to flow form into thin-walled tubes on a CNC flow-forming machine with a single roller. Design of experiments is used to predict the surface roughness of flow-formed tubes. The process parameters selected for this study are the roller axial feed, mandrel speed, and roller radius. A standard response surface methodology (RSM) called the Box Behnken design is used to perform the experimental runs. The regression model developed by RSM successfully predicts the surface roughness of AA6082 flow-formed tubes within the range of the selected process parameters.

  6. Prediction of the surface roughness of AA6082 flow-formed tubes by design of experiments

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasulu, M. [Government Polytechnic for Women Badangpet, Hyderabad (India); Komaraiah, M. [Sreenidhi Institute of Science and Technology, Hyderabad (India); Rao, C. S. Krishna Prasada [Bharat Dynamics Limited, Hyderabad (India)

    2013-06-15

    Flow forming is a modern, chipless metal forming process that is employed for the production of thin-walled seamless tubes. Experiments are conducted on AA6082 alloy pre-forms to flow form into thin-walled tubes on a CNC flow-forming machine with a single roller. Design of experiments is used to predict the surface roughness of flow-formed tubes. The process parameters selected for this study are the roller axial feed, mandrel speed, and roller radius. A standard response surface methodology (RSM) called the Box Behnken design is used to perform the experimental runs. The regression model developed by RSM successfully predicts the surface roughness of AA6082 flow-formed tubes within the range of the selected process parameters.

  7. Predicting Ligand Binding Sites on Protein Surfaces by 3-Dimensional Probability Density Distributions of Interacting Atoms

    Science.gov (United States)

    Jian, Jhih-Wei; Elumalai, Pavadai; Pitti, Thejkiran; Wu, Chih Yuan; Tsai, Keng-Chang; Chang, Jeng-Yih; Peng, Hung-Pin; Yang, An-Suei

    2016-01-01

    Predicting ligand binding sites (LBSs) on protein structures, which are obtained either from experimental or computational methods, is a useful first step in functional annotation or structure-based drug design for the protein structures. In this work, the structure-based machine learning algorithm ISMBLab-LIG was developed to predict LBSs on protein surfaces with input attributes derived from the three-dimensional probability density maps of interacting atoms, which were reconstructed on the query protein surfaces and were relatively insensitive to local conformational variations of the tentative ligand binding sites. The prediction accuracy of the ISMBLab-LIG predictors is comparable to that of the best LBS predictors benchmarked on several well-established testing datasets. More importantly, the ISMBLab-LIG algorithm has substantial tolerance to the prediction uncertainties of computationally derived protein structure models. As such, the method is particularly useful for predicting LBSs not only on experimental protein structures without known LBS templates in the database but also on computationally predicted model protein structures with structural uncertainties in the tentative ligand binding sites. PMID:27513851

  8. Data fusion analysis of a surface direct-current resistivity and well pick data set

    International Nuclear Information System (INIS)

    Clayton, E.A.; Lewis, R.E.

    1995-09-01

    Pacific Northwest Laboratory (PNL) has been tasked with testing, debugging, and refining the Hanford Site data fusion workstation (DFW), with the assistance of Coleman Research Corporation (CRC), before delivering the DFW to the environmental restoration client at the Hanford Site. Data fusion is the mathematical combination (or fusion) of disparate data sets into a single interpretation. The data fusion software used in this study was developed by CRC. This report discusses the results of evaluating a surface direct-current (dc) resistivity and well-pick data set using two methods: data fusion technology and commercially available software (i.e., RESIX Plus from Interpex Ltd., Golden, Colorado), the conventional method of analysis. The report compares the two technologies; describes the survey, procedures, and results; and includes conclusions and recommendations. The surface dc resistivity and well-pick data set had been acquired by PNL from a study performed in May 1993 at Eielson Air Force Base near Fairbanks, Alaska. The resistivity survey data were acquired to map the top of permafrost in support of a hydrogeologic study. This data set provided an excellent opportunity to test and refine the dc resistivity capabilities of the DFW; previously, the data fusion software was untested on dc resistivity data. The DFW was used to evaluate the dc resistivity survey data and to produce a 3-dimensional earth model of the study area

  9. Current status and new trends in the methodology of safety assessment for near surface disposal facilities

    International Nuclear Information System (INIS)

    Ilie, Petre; Didita, Liana; Danchiv, Alexandru

    2008-01-01

    The main goal of this paper is to present the status of the safety assessment methodology at the end of IAEA CRP 'Application of Safety Assessment Methodology for Near-Surface Radioactive Waste Disposal Facilities (ASAM)', and the new trends outlined at the launch of the follow-up project 'Practical Implementation of Safety Assessment Methodologies in a Context of Safety Case of Near-Surface Facilities (PRISM)'. Over the duration of the ASAM project, the ISAM methodology was confirmed as providing a good framework for conducting safety assessment calculations. In contrast, ASAM project identified the limitations of the ISAM methodology as currently formulated. The major limitations are situated in the area of the use of safety assessment for informing practical decisions about alternative waste and risk management strategies for real disposal sites. As a result of the limitation of the ISAM methodology, the PRISM project is established as an extension of the ISAM and ASAM projects. Based on the outcomes of the ASAM project, the main objective of the PRISM project are: 1 - to develop an overview of what constitutes an adequate safety case and safety assessment with a view to supporting decision making processes; 2 - to provide practical illustrations of how the safety assessment methodology could be used for addressing some specific issues arising from the ASAM project and national cases; 3 - to support harmonization with the IAEA's international safety standards. (authors)

  10. Ulnar Nerve Conduction Block Using Surface Kilohertz Frequency Alternating Current: A Feasibility Study.

    Science.gov (United States)

    Springer, Shmuel; Kozol, Zvi; Reznic, Zvi

    2018-03-08

    The aim of this study was to test the effects of kilohertz frequency alternating current (KHFAC) surface stimulation applied to the ulnar nerve on force and myoelectrical activity of the abductor digiti minimi (ADM) muscle. Eighteen healthy volunteers (age: 27.6 ± 7.9 years; 10 males, 8 females) were included in the study. Each subject participated in one session during which a biphasic 7 kHz rectangular pulse was delivered above the medial epicondyle of the humerus to induce ulnar nerve blocking. ADM electromyographic (EMG) activity and contraction force were measured before (Pre), immediately after, and following 5 and 10 min post stimulation (post 1, post 2). The results showed that EMG activity decreased immediately after stimulation compared to prestimulation, it returned to the level of prestimulation at 5 min (post 1), and decreased again at 10 min (post 2). Furthermore, analysis of compound adjusted z-score indicated significant decrease of force and myoelectrical activity immediately, and 10 min post stimulation. The findings, which demonstrate that KHFAC surface stimulation of the ulnar nerve may decrease the motor activity of intrinsic hand muscle, can help to develop future methods of neuromodulation to treat hand spasticity. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  11. Pyogenic liver abscess: current status and predictive factors for recurrence and mortality of first episodes.

    Science.gov (United States)

    Czerwonko, Matías E; Huespe, Pablo; Bertone, Santiago; Pellegrini, Pablo; Mazza, Oscar; Pekolj, Juan; de Santibañes, Eduardo; Hyon, Sung Ho; de Santibañes, Martín

    2016-12-01

    In times of modern surgery, transplantation and percutaneous techniques, pyogenic liver abscess (PLA) has essentially become a problem of biliary or iatrogenic origin. In the current scenario, diagnostic approach, clinical behavior and therapeutic outcomes have not been profoundly studied. This study analyzes the clinical and microbiological features, diagnostic methods, therapeutic management and predictive factors for recurrence and mortality of first episodes of PLA. A retrospective single-center study was conducted including 142 patients admitted to the Hospital Italiano de Buenos Aires, between 2005 and 2015 with first episodes of PLA. Prevailing identifiable causes were biliary diseases (47.9%) followed by non-biliary percutaneous procedures (NBIPLA, 15.5%). Seventeen patients (12%) were liver recipients. Eleven patients (7.8%) died and 18 patients (13.7%) had recurrence in the first year of follow up. The isolation of multiresistant organisms (p = 0.041) and a history of cholangitis (p 5 mg/dL (p = 0.022) and bilateral involvement (p = 0.014) in the multivariate analysis. NBPLA and PLA after transplantation may be increasing among the population of PLA in referral centers. History of cholangitis is a strong predictor for recurrence. Mortality is associated to hiperbilirrubinemia and anatomical distribution of the lesions. Copyright © 2016 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.

  12. Non-reciprocal Oersted field contribution to the current-induced frequency shift of magnetostatic surface waves

    OpenAIRE

    Haidar, Mohammad; Bailleul, Matthieu; Kostylev, Mikhail; Lao, Yuyan

    2013-01-01

    The influence of an electrical current on the propagation of magnetostatic surface waves is investigated in a relatively thick (40 nm) permalloy film both experimentally and theoretically. Contrary to previously studied thinner films where the dominating effect is the current-induced spin-wave Doppler shift, the magnetic field generated by the current (Oersted field) is found to induce a strong non-reciprocal frequency shift which overcompensates the Doppler shift. The measured current induce...

  13. On the sensitivity of numerical weather prediction to remotely sensed marine surface wind data - A simulation study

    Science.gov (United States)

    Cane, M. A.; Cardone, V. J.; Halem, M.; Halberstam, I.

    1981-01-01

    The reported investigation has the objective to assess the potential impact on numerical weather prediction (NWP) of remotely sensed surface wind data. Other investigations conducted with similar objectives have not been satisfactory in connection with a use of procedures providing an unrealistic distribution of initial errors. In the current study, care has been taken to duplicate the actual distribution of information in the conventional observing system, thus shifting the emphasis from accuracy of the data to the data coverage. It is pointed out that this is an important consideration in assessing satellite observing systems since experience with sounder data has shown that improvements in forecasts due to satellite-derived information is due less to a general error reduction than to the ability to fill data-sparse regions. The reported study concentrates on the evaluation of the observing system simulation experimental design and on the assessment of the potential of remotely sensed marine surface wind data.

  14. Uncertainties in predicting rice yield by current crop models under a wide range of climatic conditions

    NARCIS (Netherlands)

    Li, T.; Hasegawa, T.; Yin, X.; Zhu, Y.; Boote, K.; Adam, M.; Bregaglio, S.; Buis, S.; Confalonieri, R.; Fumoto, T.; Gaydon, D.; Marcaida III, M.; Nakagawa, H.; Oriol, P.; Ruane, A.C.; Ruget, F.; Singh, B.; Singh, U.; Tang, L.; Yoshida, H.; Zhang, Z.; Bouman, B.

    2015-01-01

    Predicting rice (Oryza sativa) productivity under future climates is important for global food security. Ecophysiological crop models in combination with climate model outputs are commonly used in yield prediction, but uncertainties associated with crop models remain largely unquantified. We

  15. Wave-current interaction near the Gulf Stream during the surface wave dynamics experiment

    Science.gov (United States)

    Wang, David W.; Liu, Antony K.; Peng, Chih Y.; Meindl, Eric A.

    1994-01-01

    This paper presents a case study on the wave-current interaction near the local curvature of a Gulf Stream meander. The wave data were obtained from in situ measurements by a pitch-roll discus buoy during the Surface Wave Dynamics Experiment (SWADE) conducted off Wallops Island, Virginia, from October 1990 to March 1991. Owing to the advection of the Gulf Stream by the semidiurnal tide, the discus buoy was alternately located outside and inside the Gulf Stream. The directional wave measurements from the buoy show the changes in wave direction, wave energy, and directional spreading when waves encountered the current in the Gulf Stream meanders. A wave refraction model, using the ray-tracing method with an estimated Gulf Stream velocity field and meandering condition, was used to simulate wave refraction patterns and to estimate wave parameters at relative locations corresponding to buoy measurements. The numerical simulation shows that a focusing zone of wave rays was formed near the boundary and behind the crest of a simulated Gulf Stream meander. The focusing of wave rays causes changes in wave direction, increases in wave energy, and decreases in wave directional spreading, which are in good agreement with the results from the buoy measurements.

  16. Observing the Agulhas Current with sea surface temperature and altimetry data: challenges and perspectives

    CSIR Research Space (South Africa)

    Krug, Marjolaine, J

    2014-06-01

    Full Text Available -Red Sea Surface Temperature datasets still suffer from inadequate cloud masking algorithms, particularly in regions of strong temperature gradient. Despite both Sea Surface Height and Sea Surface Temperature observations being severely compromised...

  17. Ocular surface squamous neoplasia in HIV-infected patients: current perspectives

    Directory of Open Access Journals (Sweden)

    Rathi SG

    2018-03-01

    Full Text Available Shweta Gupta Rathi, Anasua Ganguly Kapoor, Swathi Kaliki Operation Eyesight Universal Institute for Eye Cancer, LV Prasad Eye Institute, Hyderabad, India Abstract: Ocular surface squamous neoplasia (OSSN refers to a spectrum of conjunctival and corneal epithelial tumors including dysplasia, carcinoma in situ, and invasive carcinoma. In this article, we discuss the current perspectives of OSSN associated with HIV infection, focusing mainly on the epidemiology, pathophysiology, clinical manifestations, diagnosis, and treatment of these tumors in patients with HIV. Upsurge in the incidence of OSSN with the HIV pandemic most severely affected sub-Saharan Africa, due to associated risk factors, such as human papilloma virus and solar ultraviolet exposure. OSSN has been reported as the first presenting sign of HIV/AIDS in 26%–86% cases, and seropositivity is noted in 38%–92% OSSN patients. Mean age at presentation of OSSN has dropped to the third to fourth decade in HIV-positive patients in developing countries. HIV-infected patients reveal large aggressive tumors, higher-grade malignancy, higher incidence of corneal, scleral, and orbital invasion, advanced-stage T4 tumors, higher need for extended enucleation/exenteration, and increased risk of tumor recurrence. Current management of OSSN in HIV-positive individuals is based on standard treatment guidelines described for OSSN in the general population, as there is little information available about various treatment modalities or their outcomes in patients with HIV. OSSN can occur at any time in the disease course of HIV/AIDS, and no significant trend has been discovered between CD4 count and grade of OSSN. Furthermore, the effect of highly active antiretroviral therapy on OSSN is controversial. The current recommendation is to conduct HIV screening in all cases presenting with OSSN to rule out undiagnosed HIV infection. Patient counseling is crucial, with emphasis on regular follow-up to address

  18. Ocular surface squamous neoplasia in HIV-infected patients: current perspectives.

    Science.gov (United States)

    Rathi, Shweta Gupta; Ganguly Kapoor, Anasua; Kaliki, Swathi

    2018-01-01

    Ocular surface squamous neoplasia (OSSN) refers to a spectrum of conjunctival and corneal epithelial tumors including dysplasia, carcinoma in situ, and invasive carcinoma. In this article, we discuss the current perspectives of OSSN associated with HIV infection, focusing mainly on the epidemiology, pathophysiology, clinical manifestations, diagnosis, and treatment of these tumors in patients with HIV. Upsurge in the incidence of OSSN with the HIV pandemic most severely affected sub-Saharan Africa, due to associated risk factors, such as human papilloma virus and solar ultraviolet exposure. OSSN has been reported as the first presenting sign of HIV/AIDS in 26%-86% cases, and seropositivity is noted in 38%-92% OSSN patients. Mean age at presentation of OSSN has dropped to the third to fourth decade in HIV-positive patients in developing countries. HIV-infected patients reveal large aggressive tumors, higher-grade malignancy, higher incidence of corneal, scleral, and orbital invasion, advanced-stage T4 tumors, higher need for extended enucleation/exenteration, and increased risk of tumor recurrence. Current management of OSSN in HIV-positive individuals is based on standard treatment guidelines described for OSSN in the general population, as there is little information available about various treatment modalities or their outcomes in patients with HIV. OSSN can occur at any time in the disease course of HIV/AIDS, and no significant trend has been discovered between CD4 count and grade of OSSN. Furthermore, the effect of highly active antiretroviral therapy on OSSN is controversial. The current recommendation is to conduct HIV screening in all cases presenting with OSSN to rule out undiagnosed HIV infection. Patient counseling is crucial, with emphasis on regular follow-up to address high recurrence rates and early presentation to an ophthalmologist for of any symptoms in the unaffected eye. Effective evidence-based interventions are needed to allow early diagnosis

  19. The Surface Velocity Structure of the Florida Current in a Jet Coordinate Frame

    Science.gov (United States)

    Archer, Matthew R.; Shay, Lynn K.; Johns, William E.

    2017-11-01

    The structure and variability of the Florida Current between 25° and 26°N are investigated using HF radar ocean current measurements to provide the most detailed view of the surface jet to date. A 2-D jet coordinate analysis is performed to define lateral displacements of the jet in time (meandering), and associated structural variations over a 2 year period (2005-2006). In the jet coordinate frame, core speed has a median value of ˜160 cm s-1 at the central latitude of the array (25.4°N), with a standard deviation (STD) of 35 cm s-1. The jet meanders at timescales of 3-30 days, with a STD of 8 km, and a downstream phase speed of ˜80 km d-1. Meandering accounts for ˜45% of eddy kinetic energy computed in a fixed (geographical) reference frame. Core speed, width, and shear undergo the same dominant 3-30 day variability, plus an annual cycle that matches seasonality of alongshore wind stress. Jet transport at 25.4°N exhibits a different seasonality to volume transport at 27°N, most likely driven by input from the Northwest Providence Channel. Core speed correlates inversely with Miami sea level fluctuations such that a 40 cm s-1 deceleration is associated with a ˜10 cm elevation in sea level, although there is no correlation of sea level to jet meandering or width. Such accurate quantification of the Florida Current's variability is critical to understand and forecast future changes in the climate system of the North Atlantic, as well as local impacts on coastal circulation and sea level variability along south Florida's coastline.

  20. Prediction of Human Drug Targets and Their Interactions Using Machine Learning Methods: Current and Future Perspectives.

    Science.gov (United States)

    Nath, Abhigyan; Kumari, Priyanka; Chaube, Radha

    2018-01-01

    Identification of drug targets and drug target interactions are important steps in the drug-discovery pipeline. Successful computational prediction methods can reduce the cost and time demanded by the experimental methods. Knowledge of putative drug targets and their interactions can be very useful for drug repurposing. Supervised machine learning methods have been very useful in drug target prediction and in prediction of drug target interactions. Here, we describe the details for developing prediction models using supervised learning techniques for human drug target prediction and their interactions.

  1. New approaches to predicting surface fuel moisture in south east Australian forests

    Science.gov (United States)

    Sheridan, Gary; Nyman, Petter; Hawthorne, Sandra; Bovill, William; Walsh, Sean; Baillie, Craig; Duff, Thomas; Tolhurst, Kevin; Lane, Patrick

    2016-04-01

    The capacity to predict of the moisture content (FMC) of fine surface fuels in mountainous south east Australian forests has improved dramatically in recent years due to the convergence of several new technologies, including i) improved process-based account-keeping type FMC models, ii) improved understanding and representation of topographic effects (aspect, drainage position, elevation) on surface fuel and soil moisture, iii) improved methods for downscaling weather variables (eg. rainfall/throughfall, short-wave radiation) using digital elevation models and airborne LIDaR, and, iv) new in-situ sensor technologies (fuelsticks, capacitance sensors, Ibuttons) for continuously monitoring surface fuels and within-litter micro-climate conditions, generating datasets of unprecedented temporal resolution and continuity for model development and testing under real field conditions across a broad range of forests, landscapes and climates. In this study the combined improvements in predictive capacity were quantified by comparing the field FMC observations with predictions from traditional, widely used operational FMC models, and with two new process-based models, including improved spatial parameterisation provided by the new technologies outlined above. The results are interpreted in the context of planned-burning decision making and outcomes, and bushfire modelling and management. The initial results showed that the new approaches to FMC prediction offered substantial improvements over the traditional methods and could be reasonably implemented at operational scales.

  2. Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

    OpenAIRE

    Isern-Fontanet, Jordi; Ballabrera-Poy, Joaquim; Turiel, Antonio; García-Ladona, Emilio

    2017-01-01

    Ocean currents play a key role in Earth's climate – they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dy...

  3. Predicting muscle fatigue: a response surface approximation based on proper generalized decomposition technique.

    Science.gov (United States)

    Sierra, M; Grasa, J; Muñoz, M J; Miana-Mena, F J; González, D

    2017-04-01

    A novel technique is proposed to predict force reduction in skeletal muscle due to fatigue under the influence of electrical stimulus parameters and muscle physiological characteristics. Twelve New Zealand white rabbits were divided in four groups ([Formula: see text]) to obtain the active force evolution of in vitro Extensor Digitorum Longus muscles for an hour of repeated contractions under different electrical stimulation patterns. Left and right muscles were tested, and a total of 24 samples were used to construct a response surface based in the proper generalized decomposition. After the response surface development, one additional rabbit was used to check the predictive potential of the technique. This multidimensional surface takes into account not only the decay of the maximum repeated peak force, but also the shape evolution of each contraction, muscle weight, electrical input signal and stimulation protocol. This new approach of the fatigue simulation challenge allows to predict, inside the multispace surface generated, the muscle response considering other stimulation patterns, different tissue weight, etc.

  4. A role of the Atlantic Ocean in predicting summer surface air temperature over North East Asia?

    Science.gov (United States)

    Monerie, Paul-Arthur; Robson, Jon; Dong, Buwen; Dunstone, Nick

    2017-10-01

    We assess the ability of the DePreSys3 prediction system to predict the summer (JJAS) surface-air temperature over North East Asia. DePreSys3 is based on a high resolution ocean-atmosphere coupled climate prediction system ( 60 km in the atmosphere and 25 km in the ocean), which is full-field initialized from 1960 to 2014 (26 start-dates). We find skill in predicting surface-air temperature, relative to a long-term trend, for 1 and 2-5 year lead-times over North East Asia, the North Atlantic Ocean and Eastern Europe. DePreSys3 also reproduces the interdecadal evolution of surface-air temperature over the North Atlantic subpolar gyre and North East Asia for both lead times, along with the strong warming that occurred in the mid-1990s over both areas. Composite analysis reveals that the skill at capturing interdecadal changes in North East Asia is associated with the propagation of an atmospheric Rossby wave, which follows the subtropical jet and modulates surface-air temperature from Europe to Eastern Asia. We hypothesise that this `circumglobal teleconnection' pattern is excited over the Atlantic Ocean and is related to Atlantic multi-decadal variability and the associated changes in precipitation over the Sahel and the subtropical Atlantic Ocean. This mechanism is robust for the 2-5 year lead-time. For the 1 year lead-time the Pacific Ocean also plays an important role in leading to skill in predicting SAT over Northeast Asia. Increased temperatures and precipitation over the western Pacific Ocean was found to be associated with a Pacific-Japan like-pattern, which can affect East Asia's climate.

  5. Nonequilibrium Molecular Simulations of New Ionic Lubricants at Metallic Surfaces: Prediction of the Friction.

    Science.gov (United States)

    Mendonça, Ana C F; Pádua, Agílio A H; Malfreyt, Patrice

    2013-03-12

    We report nonequilibrium molecular dynamics of ionic liquids interacting with metallic surfaces. A specific set of interaction parameters for ionic liquids composed of alkylammonium cations and alkylsulfonate anions with an iron surface, which has been previously developed (J. Chem. Theory Comput.2012, 8, 3348) is used here. We develop a procedure for a quantitative prediction of the friction coefficient at different loads and shear rates. The simulated friction coefficient agrees very well with the available experimental ones. The dependence of friction on the load, shear velocity, surface topology, and length of alkyl side chains in the ionic liquid is also investigated. The changes in the frictional forces are explained in terms of the specific arrangements and orientations of groups forming the ionic liquid at the vicinity of the surface.

  6. The effect of cathode bias (field effect) on the surface leakage current of CdZnTe detectors

    DEFF Research Database (Denmark)

    Bolotnikov, A.E.; Chen, C.M.H.; Cook, W.R.

    2003-01-01

    Surface resistivity is an important parameter of multi-electrode CZT detectors such as coplanar-grid, strip, or pixel detectors. Low surface resistivity results in a high leakage current and affects the charge collection efficiency in the areas near contacts. Thus, it is always desirable to have ...

  7. Predicting protein-protein interface residues using local surface structural similarity

    Directory of Open Access Journals (Sweden)

    Jordan Rafael A

    2012-03-01

    Full Text Available Abstract Background Identification of the residues in protein-protein interaction sites has a significant impact in problems such as drug discovery. Motivated by the observation that the set of interface residues of a protein tend to be conserved even among remote structural homologs, we introduce PrISE, a family of local structural similarity-based computational methods for predicting protein-protein interface residues. Results We present a novel representation of the surface residues of a protein in the form of structural elements. Each structural element consists of a central residue and its surface neighbors. The PrISE family of interface prediction methods uses a representation of structural elements that captures the atomic composition and accessible surface area of the residues that make up each structural element. Each of the members of the PrISE methods identifies for each structural element in the query protein, a collection of similar structural elements in its repository of structural elements and weights them according to their similarity with the structural element of the query protein. PrISEL relies on the similarity between structural elements (i.e. local structural similarity. PrISEG relies on the similarity between protein surfaces (i.e. general structural similarity. PrISEC, combines local structural similarity and general structural similarity to predict interface residues. These predictors label the central residue of a structural element in a query protein as an interface residue if a weighted majority of the structural elements that are similar to it are interface residues, and as a non-interface residue otherwise. The results of our experiments using three representative benchmark datasets show that the PrISEC outperforms PrISEL and PrISEG; and that PrISEC is highly competitive with state-of-the-art structure-based methods for predicting protein-protein interface residues. Our comparison of PrISEC with PredUs, a recently

  8. First principles predictions of electron tunneling rates between atoms and crystalline surfaces

    Science.gov (United States)

    Neidfeldt, Keith

    Charge transfer is a critical process that controls many important reactions such as photosynthesis, corrosion, and catalysis. We developed a quantitative method for calculating charge transfer rates using periodic density functional theory (DFT). This approach allows us to model from first principles the interaction between an adsorbate and arbitrary material surfaces. By deconvoluting the projected density of states of the ionization level of the atom, we can determine its width, which is proportional to the charge transfer rate. These rates can be used to predict important properties such as adsorbate excited state lifetimes and neutralization fractions for scattered ions. By comparing neutralization fractions for Li scattering off of Al(001) to experimental data, we validated our first principles method of predicting charge transfer rates. While our results are consistent with the classic Langmuir-Gurney (LG) model of adsorption for nearly-free-electron-like metal surfaces, we find several important deviations caused by the actual electronic structure of more complicated material surfaces. For example, we find that the d-band of transition metal surfaces mediates an intra-atomic hybridization of the Li ionization level. Secondly, we find that surface-projected band gaps (e.g., in Cu(111)) enhance the lifetimes of alkali atoms above surfaces containing such band gaps. In addition, our method allows us to also study atoms interacting with non-metallic surfaces where the LG model does not apply. For example, we find that alkali charge transfer rates are controlled by dangling bonds on covalently-bonded surfaces (e.g., Si(001)-(2xl)) instead of by the traditional image potential.

  9. [Current seroprevalence, vaccination and predictive value of liver enzymes for hepatitis B among refugees in Germany].

    Science.gov (United States)

    Hampel, Annika; Solbach, Philipp; Cornberg, Markus; Schmidt, Reinhold E; Behrens, Georg M N; Jablonka, Alexandra

    2016-05-01

    Currently only vague estimates exist for the seroprevalence and vaccination status for viral hepatitis B (HBV) in refugees arriving in Germany during the current refugee crisis. To assess the prevalence of hepatitis B in refugees arriving in northern Germany in 2015. In a cross-sectional study in 793 patients from all age groups tests for serological markers of hepatitis B virus infection (HBsAg, anti-HBc) and liver enzymes (ALT, AST, bilirubin, γGT, alkaline phosphatase) were performed in August 2015 at six reception centers in northern Germany. In 258 patients anti-HBs antibodies were assessed additionally. Of the tested refugees, 76.7 % were male, the median age was 28.8 ± 11.4 years, and 7.8 % were children under the age of 18. The overall prevalence of HBsAg and total anti-HBc was 2.3 % and 14.0 % respectively (2.5 % and 14.5 % in men; 1.2 % and 13.5 % in women). Prevalence was highest in 35 to 49-year-old patients for HBsAg (3.1 %) and for refugees over 50 years for anti-HBc (38 %). No immunity to Hepatitis B was found in 62 %, 18.6 % had been vaccinated against Hepatitis B, while 50 % of children aged up to 15 years (n = 12) had been vaccinated. Positive predictive values of elevated AST and ALT for detection of HBsAg was 0 and 0.016, respectively. Only two patients with a positive HBsAg had elevated transaminases. This study showed a high prevalence of HBsAg in a German refugee sample in comparison to the general German population. Liver enzymes are not an appropriate tool for screening for hepatitis B virus infection.

  10. Current status of siting a new near surface repository in Romania

    International Nuclear Information System (INIS)

    Ionita, G.; Andrei, V.; Niculae, O.; Petrescu, A.; Sorescu, A.

    2009-01-01

    Full text: The site selection process for a near surface repository dedicated for the radioactive waste resulted from the Cernavoda NPP operation and decommissioning started early in 90's. Each site selection stage included the collection of data from specific field and laboratory works as well as the appropriate safety performance evaluation. In order to assess/confirm the performance of the natural barrier of the Saligny site, the radionuclide concentration in the disposal system compartments has been evaluated, as complementary safety indicator of repository. The siting process was made in accordance with national and international regulations and standards and using a conceptual design similar to those used at L'Aube (France), ElCabril (Spain) or Mohovce (Slovak Republic). ANDRAD, the Romanian waste management organization that has continued the siting process in the last three years applied and obtained a partial siting license from CNCAN in 2008. In 2009, ANDRAD has to prepare the strategy to complete the siting process with the aims to obtain the final siting license from CNCAN and other legal approvals including stakeholders involvement in the decision process for siting the near surface repository at Saligny. Public acceptance issues, in particular acceptance of ANDRAD works in site by the local communities and their representatives are of paramount importance for ANDRAD. The siting of a new radioactive waste repository is a complex process involving multidisciplinary activities and expert teams. ANDRAD needs to develop the appropriate documentation for the safety case of such type of facility. The paper presents the results of the recent performance assessments on the natural barrier of the disposal system and current stage of the repository siting approval. (authors)

  11. Image analysis from surface scanning with an absolute eddy current coil

    International Nuclear Information System (INIS)

    Attaoui, P.

    1994-01-01

    The aim of this work is to implement processing and analysis tools applied to eddy current imaging. These cartographies are issued from steam generator tubes testing using an absolute coil. The first is to eliminate the perturbations due to probe lift-off changes which generate low frequency oscillations on the image. The principle of the processing is to rebuild a complete surface of the noise using only the points around the defect area. The geometric origin of these perturbations led to a model based on sinusoidal functions. The method consists of gradually decomposing the image into a sum of basic sinusoidal surfaces. In order to take into account all kind of cartographies (especially rolling zone) some preprocessing must be applied. The results obtained with this 'cartography flattening'are satisfactory and the phase of analysis could begin with good condition of signal ratio. The second part of this work dealt with the choice and the perfection of image processing tools which would fit the most with the defect characterization. The aim of this characterization is to give the orientation and main size of the detected defect. A morphological skeleton representation has been chosen to illustrate the defect architecture and to allow sizing. A set of tools has been elaborated to obtain an (automatic) processing according to threshold. The results for single defect are satisfactory since the sizing error is around ± 25% and orientation is nearly always correctly given. The processing for area with several defects is more complex and new complementary research directions are proposed. (author)

  12. Wrinkling Prediction in Deep Drawing by Using Response Surface Methodology and Artificial Neural Network

    OpenAIRE

    Rafizadeh, Hossein; Azimifar, Farhad; Foode, Puya; Foudeh, Mohammad Reza; Keymanesh, Mohammad

    2017-01-01

    The objective of this study is to predict influences of tooling parameters such as die and punch radius, blank holder force and friction coefficient between the die and the blank surfaces in a deep drawing process on the wrinkling height in aluminium AA5754 by using the response surface methodology (RSM) and an artificial neural network (ANN). The 3D finite element method (FEM), i.e. the Abaqus software, is employed to model the deep drawing process. In order to investigate the accuracy of th...

  13. Mapping sub-surface geostrophic currents from altimetry and a fleet of gliders

    Science.gov (United States)

    Alvarez, A.; Chiggiato, J.; Schroeder, K.

    2013-04-01

    Integrating the observations gathered by different platforms into a unique physical picture of the environment is a fundamental aspect of networked ocean observing systems. These are constituted by a spatially distributed set of sensors and platforms that simultaneously monitor a given ocean region. Remote sensing from satellites is an integral part of present ocean observing systems. Due to their autonomy, mobility and controllability, underwater gliders are envisioned to play a significant role in the development of networked ocean observatories. Exploiting synergism between remote sensing and underwater gliders is expected to result on a better characterization of the marine environment than using these observational sources individually. This study investigates a methodology to estimate the three dimensional distribution of geostrophic currents resulting from merging satellite altimetry and in situ samples gathered by a fleet of Slocum gliders. Specifically, the approach computes the volumetric or three dimensional distribution of absolute dynamic height (ADH) that minimizes the total energy of the system while being close to in situ observations and matching the absolute dynamic topography (ADT) observed from satellite at the sea surface. A three dimensional finite element technique is employed to solve the minimization problem. The methodology is validated making use of the dataset collected during the field experiment called Rapid Environmental Picture-2010 (REP-10) carried out by the NATO Undersea Research Center-NURC during August 2010. A marine region off-shore La Spezia (northwest coast of Italy) was sampled by a fleet of three coastal Slocum gliders. Results indicate that the geostrophic current field estimated from gliders and altimetry significantly improves the estimates obtained using only the data gathered by the glider fleet.

  14. Gap Filling of the CALYPSO HF Radar Sea Surface Current Data through Past Measurements and Satellite Wind Observations

    Directory of Open Access Journals (Sweden)

    Adam Gauci

    2016-01-01

    Full Text Available High frequency (HF radar installations are becoming essential components of operational real-time marine monitoring systems. The underlying technology is being further enhanced to fully exploit the potential of mapping sea surface currents and wave fields over wide areas with high spatial and temporal resolution, even in adverse meteo-marine conditions. Data applications are opening to many different sectors, reaching out beyond research and monitoring, targeting downstream services in support to key national and regional stakeholders. In the CALYPSO project, the HF radar system composed of CODAR SeaSonde stations installed in the Malta Channel is specifically serving to assist in the response against marine oil spills and to support search and rescue at sea. One key drawback concerns the sporadic inconsistency in the spatial coverage of radar data which is dictated by the sea state as well as by interference from unknown sources that may be competing with transmissions in the same frequency band. This work investigates the use of Machine Learning techniques to fill in missing data in a high resolution grid. Past radar data and wind vectors obtained from satellites are used to predict missing information and provide a more consistent dataset.

  15. Dose Prediction for surface nuclear explosions: case studies for Semipalatinsk and Lop Nur tests

    International Nuclear Information System (INIS)

    Takada, Jun

    2008-01-01

    Dose prediction method RAPS after surface nuclear explosion has been developed by using the empirical dose function of USA nuclear test. This method which provides us external total dose, dose rate at any distant, at any time for any yield of nuclear explosion, is useful for radiation protection in case of nuclear events such as terrorism and nuclear war. The validity of RAPS has been confirmed by application to historical surface nuclear test explosions. The first test case study which was done for the first test explosion of the former USSR at the Semipalatinsk Nuclear Test Site on August 29th 1949, shows a good agreement with luminescence dosimetry on a brick. This dose prediction method was applied nuclear tests in Lop Nur. The results indicate dangerous nuclear radiation influences including fatal risk in the wide Uygur area. (author)

  16. Predicting the minimum liquid surface tension activity of pseudomonads expressing biosurfactants.

    Science.gov (United States)

    Mohammed, I U; Deeni, Y; Hapca, S M; McLaughlin, K; Spiers, A J

    2015-01-01

    Bacteria produce a variety of biosurfactants capable of significantly reducing liquid (aqueous) surface tension (γ) with a range of biological roles and biotechnological uses. To determine the lowest achievable surface tension (γMin ), we tested a diverse collection of Pseudomonas-like isolates from contaminated soil and activated sludge and identified those expressing biosurfactants by drop-collapse assay. Liquid surface tension-reducing ability was quantitatively determined by tensiometry, with 57 isolates found to significantly lower culture supernatant surface tensions to 24·5-49·1 mN m(-1) . Differences in biosurfactant behaviour determined by foaming, emulsion and oil-displacement assays were also observed amongst isolates producing surface tensions of 25-27 mN m(-1) , suggesting that a range of structurally diverse biosurfactants were being expressed. Individual distribution identification (IDI) analysis was used to identify the theoretical probability distribution that best fitted the surface tension data, which predicted a γMin of 24·24 mN m(-1) . This was in agreement with predictions based on earlier work of published mixed bacterial spp. data, suggesting a fundamental limit to the ability of bacterial biosurfactants to reduce surface tensions in aqueous systems. This implies a biological restriction on the synthesis and export of these agents or a physical-chemical restriction on their functioning once produced. Numerous surveys of biosurfactant-producing bacteria have been conducted, but only recently has an attempt been made to predict the minimum liquid surface tension these surface-active agents can achieve. Here, we determine a theoretical minimum of 24 mN m(-1) by statistical analysis of tensiometry data, suggesting a fundamental limit for biosurfactant activity in bacterial cultures incubated under standard growth conditions. This raises a challenge to our understanding of biosurfactant expression, secretion and function, as well as

  17. Surface Crack Detection for Carbon Fiber Reinforced Plastic Materials Using Pulsed Eddy Current Based on Rectangular Differential Probe

    Directory of Open Access Journals (Sweden)

    Jialong Wu

    2014-01-01

    Full Text Available Aiming at the surface defect inspection of carbon fiber reinforced composite, the differential and the direct measurement finite element simulation models of pulsed eddy current flaw detection were built. The principle of differential pulsed eddy current detection was analyzed and the sensitivity of defect detection was compared through two kinds of measurements. The validity of simulation results was demonstrated by experiments. The simulation and experimental results show that the pulsed eddy current detection method based on rectangular differential probe can effectively improve the sensitivity of surface defect detection of carbon fiber reinforced composite material.

  18. MHD stability analysis of axisymmetric surface current model tokamaks close to the spheromak regime

    International Nuclear Information System (INIS)

    Honma, Toshihisa; Kaji, Ikuo; Fukai, Ichiro; Kito, Masafumi.

    1984-01-01

    In the toroidal coordinates, a stability analysis is presented for very low-aspect-ratio tokamaks with circular cross section which is described by a surface current model (SCM) of axisymmetric equilibria. The energy principle determining the stability of plasma is treated without any expansion of aspect ratio. Numerical results show that, owing to the occurrence of the non-axisymmetric (n=1) unstable modes, there exists no MHD-stable ideal SCM spheromak characterized by zero external toroidal vacuum field. Instead, a stable spheromak-type plasma which comes to the ideal SCM spheromak is provided by the configuration with a very weak external toroidal field. Close to the spheromak regime (1.0 1 aspect ratio< = 1.1), the minimum safety factor and the critical β-values increase mo notonically with aspect ratio decreasing from a large value, and curves of βsub(p) versus β in the marginal stability approach to an ideal SCM spheromak line βsub(p)=β. (author)

  19. SCO shipments from Rocky Flats - Experience and current practice [Surface Contaminated Object

    International Nuclear Information System (INIS)

    Bracken, Gary; Morris, Robert L.

    2001-01-01

    Decommissioning activities at Rocky Flats Environmental Technology Site (RFETS) are expected to generate approximately 251,000 cubic meters of low-level radioactive waste. Almost half of this will be characterized and shipped as the Department of Transportation ''Surface Contaminated Object'' (SCO) shipping class. In the 2 years since an SCO characterization method was implemented, almost 11,000 of the 18,000 cubic meters of low-level waste were SCO. RFETS experience to-date using an SCO waste characterization method has shown significant time and cost savings, reduced errors, and enhanced employee safety. SCO waste is characterized prior to packaging, near the point of generation, by any of the site's 300 Radiological Control Technicians using inexpensive radiological control survey instruments. This reduces on-site waste container moves and eliminates radiometric analysis at centrally located drum or crate counters. Containers too large for crate counters can also be characterized. Current instrumentation is not adequate to take full advantage of the SCO regulations. Future improvements in the SCO characterization and shipping process are focused on use of larger and/or reusable containers, extended-range instruments, and additional statistical methods, so that the full extent of the SCO regulations can be used

  20. Surface Modification of Direct-Current and Radio-Frequency Oxygen Plasma Treatments Enhance Cell Biocompatibility

    Directory of Open Access Journals (Sweden)

    Wan-Ching Chou

    2017-10-01

    Full Text Available The sand-blasting and acid etching (SLA method can fabricate a rough topography for mechanical fixation and long-term stability of titanium implant, but can not achieve early bone healing. This study used two kinds of plasma treatments (Direct-Current and Radio-Frequency plasma to modify the SLA-treated surface. The modification of plasma treatments creates respective power range and different content functional OH groups. The results show that the plasma treatments do not change the micron scale topography, and plasma-treated specimens presented super hydrophilicity. The X-ray photoelectron spectroscopy (XPS-examined result showed that the functional OH content of the RF plasma-treated group was higher than the control (SLA and DC treatment groups. The biological responses (protein adsorption, cell attachment, cell proliferation, and differentiation promoted after plasma treatments, and the cell responses, have correlated to the total content of amphoteric OH groups. The experimental results indicated that plasma treatments can create functional OH groups on SLA-treated specimens, and the RF plasma-treated SLA implant thus has potential for achievement of bone healing in early stage of implantation.

  1. Transport of contaminants by Arctic sea ice and surface ocean currents

    International Nuclear Information System (INIS)

    Pfirman, S.

    1995-01-01

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

  2. Application of Monochromatic Ocean Wave Forecasts to Prediction of Wave-Induced Currents

    Science.gov (United States)

    Poole, L. R.

    1975-01-01

    Stoke's wave-induced currents are compared, for variety of wind conditions resulting in partially developed seas and for two water depths, with currents induced by average and significant monochromatic waves related to Bretschneider spectrum.

  3. Recognition and prediction of individual and combined muscular activation modes via surface EMG analysis

    Directory of Open Access Journals (Sweden)

    Daniel Graupe

    2010-09-01

    Full Text Available The paper discusses how recognition of individual and combined muscular activation modes (functions and the prediction of intended such modes can be accomplished by identifying parameters of noninvasive surface EMG signals. It outlines the mathematical analysis of surface EMG signal to facilitate such recognition and related prediction, including recognition of intention (in terms of attempts to activate motor functions from the EMG, without accessing the CNS itself, in cases where a patient, say, a high-level amputee does not have the final-activation muscles and joints. The EMG activity thus allows to interpret and recognize CNS commands from minute variations in the parameters of surface EMG signals that record changes in the firing of motor neurons triggering contractions in related muscle fibers. We note that although in popular media this is sometimes referred to as detection of “thoughts”, no thoughts are detected, but only motor-outcomes of thoughts as found in the EMG signal. Examples of concrete cases where such recognition or prediction were accomplished in the author’s lab and in devices that came out of that lab, are given as are references to these in the literature over the last 35 years.

  4. Ocean surface waves in Hurricane Ike (2008) and Superstorm Sandy (2012): Coupled model predictions and observations

    Science.gov (United States)

    Chen, Shuyi S.; Curcic, Milan

    2016-07-01

    Forecasting hurricane impacts of extreme winds and flooding requires accurate prediction of hurricane structure and storm-induced ocean surface waves days in advance. The waves are complex, especially near landfall when the hurricane winds and water depth varies significantly and the surface waves refract, shoal and dissipate. In this study, we examine the spatial structure, magnitude, and directional spectrum of hurricane-induced ocean waves using a high resolution, fully coupled atmosphere-wave-ocean model and observations. The coupled model predictions of ocean surface waves in Hurricane Ike (2008) over the Gulf of Mexico and Superstorm Sandy (2012) in the northeastern Atlantic and coastal region are evaluated with the NDBC buoy and satellite altimeter observations. Although there are characteristics that are general to ocean waves in both hurricanes as documented in previous studies, wave fields in Ike and Sandy possess unique properties due mostly to the distinct wind fields and coastal bathymetry in the two storms. Several processes are found to significantly modulate hurricane surface waves near landfall. First, the phase speed and group velocities decrease as the waves become shorter and steeper in shallow water, effectively increasing surface roughness and wind stress. Second, the bottom-induced refraction acts to turn the waves toward the coast, increasing the misalignment between the wind and waves. Third, as the hurricane translates over land, the left side of the storm center is characterized by offshore winds over very short fetch, which opposes incoming swell. Landfalling hurricanes produce broader wave spectra overall than that of the open ocean. The front-left quadrant is most complex, where the combination of windsea, swell propagating against the wind, increasing wind-wave stress, and interaction with the coastal topography requires a fully coupled model to meet these challenges in hurricane wave and surge prediction.

  5. An Analytical Model for Prediction of Magnetic Flux Leakage from Surface Defects in Ferromagnetic Tubes

    Directory of Open Access Journals (Sweden)

    Suresh V.

    2016-02-01

    Full Text Available In this paper, an analytical model is proposed to predict magnetic flux leakage (MFL signals from the surface defects in ferromagnetic tubes. The analytical expression consists of elliptic integrals of first kind based on the magnetic dipole model. The radial (Bz component of leakage fields is computed from the cylindrical holes in ferromagnetic tubes. The effectiveness of the model has been studied by analyzing MFL signals as a function of the defect parameters and lift-off. The model predicted results are verified with experimental results and a good agreement is observed between the analytical and the experimental results. This analytical expression could be used for quick prediction of MFL signals and also input data for defect reconstructions in inverse MFL problem.

  6. Tumor Surface Regularity at MR Imaging Predicts Survival and Response to Surgery in Patients with Glioblastoma.

    Science.gov (United States)

    Pérez-Beteta, Julián; Molina-García, David; Ortiz-Alhambra, José A; Fernández-Romero, Antonio; Luque, Belén; Arregui, Elena; Calvo, Manuel; Borrás, José M; Meléndez, Bárbara; Rodríguez de Lope, Ángel; Moreno de la Presa, Raquel; Iglesias Bayo, Lidia; Barcia, Juan A; Martino, Juan; Velásquez, Carlos; Asenjo, Beatriz; Benavides, Manuel; Herruzo, Ismael; Revert, Antonio; Arana, Estanislao; Pérez-García, Víctor M

    2018-04-03

    Purpose To evaluate the prognostic and predictive value of surface-derived imaging biomarkers obtained from contrast material-enhanced volumetric T1-weighted pretreatment magnetic resonance (MR) imaging sequences in patients with glioblastoma multiforme. Materials and Methods A discovery cohort from five local institutions (165 patients; mean age, 62 years ± 12 [standard deviation]; 43% women and 57% men) and an independent validation cohort (51 patients; mean age, 60 years ± 12; 39% women and 61% men) from The Cancer Imaging Archive with volumetric T1-weighted pretreatment contrast-enhanced MR imaging sequences were included in the study. Clinical variables such as age, treatment, and survival were collected. After tumor segmentation and image processing, tumor surface regularity, measuring how much the tumor surface deviates from a sphere of the same volume, was obtained. Kaplan-Meier, Cox proportional hazards, correlations, and concordance indexes were used to compare variables and patient subgroups. Results Surface regularity was a powerful predictor of survival in the discovery (P = .005, hazard ratio [HR] = 1.61) and validation groups (P = .05, HR = 1.84). Multivariate analysis selected age and surface regularity as significant variables in a combined prognostic model (P surface regularity was a predictor of survival for patients who underwent complete resection (P = .01, HR = 1.90). Tumors with irregular surfaces did not benefit from total over subtotal resections (P = .57, HR = 1.17), but those with regular surfaces did (P = .004, HR = 2.07). Conclusion The surface regularity obtained from high-resolution contrast-enhanced pretreatment volumetric T1-weighted MR images is a predictor of survival in patients with glioblastoma. It may help in classifying patients for surgery. © RSNA, 2018 Online supplemental material is available for this article.

  7. Electron-beam induced current characterization of back-surface field solar cells using a chopped scanning electron microscope beam

    Science.gov (United States)

    Luke, K. L.; Cheng, L.-J.

    1984-01-01

    A chopped electron beam induced current (EBIC) technique for the chacterization of back-surface field (BSF) solar cells is presented. It is shown that the effective recombination velocity of the low-high junction forming the back-surface field of BSF cells, in addition to the diffusion length and the surface recombination velocity of the surface perpendicular to both the p-n and low-high junctions, can be determined from the data provided by a single EBIC scan. The method for doing so is described and illustrated. Certain experimental considerations taken to enhance the quality of the EBIC data are also discussed.

  8. A study of direct-current surface discharge plasma for a Mach 3 supersonic flow control

    Science.gov (United States)

    Shin, Jichul

    A direct-current, non-equilibrium surface glow discharge plasma in the presence of a Mach 2.85 flow is studied experimentally for flow control applications. The discharge is generated with pin-like electrodes flush mounted on a ceramic plate with sustaining currents from 25 mA to 300 mA. In the presence of a supersonic flow, two distinct discharge modes - diffuse and constricted - are observed depending on the flow and discharge operating conditions. In cathode upstream location, both diffuse and constricted discharges are observed while in cathode downstream location, the discharge mostly exhibits either constricted mode or bistable mixed mode. The effect of the discharge on the flow ("plasma actuation'') is characterized by the appearance of a weak shock wave in the vicinity of the discharge. The shock is observed at low powers (˜10 W) for the diffuse discharge mode but is absent for the higher power (˜100 W) constricted mode. High speed laser schlieren imaging suggests that the diffuse mode plasma actuation is rapid as it occurs on a time scale that is less than 100 microsec. Rotational (gas) and vibrational temperatures within the discharge are estimated by emission spectral line fits of N 2 and N+2 rovibronic bands near 365-395 nm. The electronic temperatures are estimated by using the Boltzmann plot method for Fe(I) atomic lines. Rotational temperatures are found to be high (˜1500 K) in the absence of a flow but drop sharply (˜500 K) in the presence of a supersonic flow for both the diffuse and constricted discharge modes. The vibrational and electronic temperatures are measured to be about 3000 K and 1.25 eV (14500 K), respectively, and these temperatures are the same with and without flow. The gas (rotational) temperature spatial profiles above the cathode surface are found to be similar for the diffuse and constricted modes indicating that dilatational effects due to gas heating are similar. However, complete absence of flow actuation for the

  9. Application of Response Surface Methods To Determine Conditions for Optimal Genomic Prediction

    Science.gov (United States)

    Howard, Réka; Carriquiry, Alicia L.; Beavis, William D.

    2017-01-01

    An epistatic genetic architecture can have a significant impact on prediction accuracies of genomic prediction (GP) methods. Machine learning methods predict traits comprised of epistatic genetic architectures more accurately than statistical methods based on additive mixed linear models. The differences between these types of GP methods suggest a diagnostic for revealing genetic architectures underlying traits of interest. In addition to genetic architecture, the performance of GP methods may be influenced by the sample size of the training population, the number of QTL, and the proportion of phenotypic variability due to genotypic variability (heritability). Possible values for these factors and the number of combinations of the factor levels that influence the performance of GP methods can be large. Thus, efficient methods for identifying combinations of factor levels that produce most accurate GPs is needed. Herein, we employ response surface methods (RSMs) to find the experimental conditions that produce the most accurate GPs. We illustrate RSM with an example of simulated doubled haploid populations and identify the combination of factors that maximize the difference between prediction accuracies of best linear unbiased prediction (BLUP) and support vector machine (SVM) GP methods. The greatest impact on the response is due to the genetic architecture of the population, heritability of the trait, and the sample size. When epistasis is responsible for all of the genotypic variance and heritability is equal to one and the sample size of the training population is large, the advantage of using the SVM method vs. the BLUP method is greatest. However, except for values close to the maximum, most of the response surface shows little difference between the methods. We also determined that the conditions resulting in the greatest prediction accuracy for BLUP occurred when genetic architecture consists solely of additive effects, and heritability is equal to one. PMID

  10. Effects of modeled tropical sea surface temperature variability on coral reef bleaching predictions

    Science.gov (United States)

    van Hooidonk, R.; Huber, M.

    2012-03-01

    Future widespread coral bleaching and subsequent mortality has been projected using sea surface temperature (SST) data derived from global, coupled ocean-atmosphere general circulation models (GCMs). While these models possess fidelity in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. Such weaknesses most likely reduce the accuracy of predicting coral bleaching, but little attention has been paid to the important issue of understanding potential errors and biases, the interaction of these biases with trends, and their propagation in predictions. To analyze the relative importance of various types of model errors and biases in predicting coral bleaching, various intra- and inter-annual frequency bands of observed SSTs were replaced with those frequencies from 24 GCMs 20th century simulations included in the Intergovernmental Panel on Climate Change (IPCC) 4th assessment report. Subsequent thermal stress was calculated and predictions of bleaching were made. These predictions were compared with observations of coral bleaching in the period 1982-2007 to calculate accuracy using an objective measure of forecast quality, the Peirce skill score (PSS). Major findings are that: (1) predictions are most sensitive to the seasonal cycle and inter-annual variability in the ENSO 24-60 months frequency band and (2) because models tend to understate the seasonal cycle at reef locations, they systematically underestimate future bleaching. The methodology we describe can be used to improve the accuracy of bleaching predictions by characterizing the errors and uncertainties involved in the predictions.

  11. Use of Ensemble Numerical Weather Prediction Data for Inversely Determining Atmospheric Refractivity in Surface Ducting Conditions

    Science.gov (United States)

    Greenway, D. P.; Hackett, E.

    2017-12-01

    Under certain atmospheric refractivity conditions, propagated electromagnetic waves (EM) can become trapped between the surface and the bottom of the atmosphere's mixed layer, which is referred to as surface duct propagation. Being able to predict the presence of these surface ducts can reap many benefits to users and developers of sensing technologies and communication systems because they significantly influence the performance of these systems. However, the ability to directly measure or model a surface ducting layer is challenging due to the high spatial resolution and large spatial coverage needed to make accurate refractivity estimates for EM propagation; thus, inverse methods have become an increasingly popular way of determining atmospheric refractivity. This study uses data from the Coupled Ocean/Atmosphere Mesoscale Prediction System developed by the Naval Research Laboratory and instrumented helicopter (helo) measurements taken during the Wallops Island Field Experiment to evaluate the use of ensemble forecasts in refractivity inversions. Helo measurements and ensemble forecasts are optimized to a parametric refractivity model, and three experiments are performed to evaluate whether incorporation of ensemble forecast data aids in more timely and accurate inverse solutions using genetic algorithms. The results suggest that using optimized ensemble members as an initial population for the genetic algorithms generally enhances the accuracy and speed of the inverse solution; however, use of the ensemble data to restrict parameter search space yields mixed results. Inaccurate results are related to parameterization of the ensemble members' refractivity profile and the subsequent extraction of the parameter ranges to limit the search space.

  12. Predicting tooth surface loss using genetic algorithms-optimized artificial neural networks.

    Science.gov (United States)

    Al Haidan, Ali; Abu-Hammad, Osama; Dar-Odeh, Najla

    2014-01-01

    Our aim was to predict tooth surface loss in individuals without the need to conduct clinical examinations. Artificial neural networks (ANNs) were used to construct a mathematical model. Input data consisted of age, smoker status, type of tooth brush, brushing, and consumption of pickled food, fizzy drinks, orange, apple, lemon, and dried seeds. Output data were the sum of tooth surface loss scores for selected teeth. The optimized constructed ANN consisted of 2-layer network with 15 neurons in the first layer and one neuron in the second layer. The data of 46 subjects were used to build the model, while the data of 15 subjects were used to test the model. Accepting an error of ±5 scores for all chosen teeth, the accuracy of the network becomes more than 80%. In conclusion, this study shows that modeling tooth surface loss using ANNs is possible and can be achieved with a high degree of accuracy.

  13. Predicting Tooth Surface Loss Using Genetic Algorithms-Optimized Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Ali Al Haidan

    2014-01-01

    Full Text Available Our aim was to predict tooth surface loss in individuals without the need to conduct clinical examinations. Artificial neural networks (ANNs were used to construct a mathematical model. Input data consisted of age, smoker status, type of tooth brush, brushing, and consumption of pickled food, fizzy drinks, orange, apple, lemon, and dried seeds. Output data were the sum of tooth surface loss scores for selected teeth. The optimized constructed ANN consisted of 2-layer network with 15 neurons in the first layer and one neuron in the second layer. The data of 46 subjects were used to build the model, while the data of 15 subjects were used to test the model. Accepting an error of ±5 scores for all chosen teeth, the accuracy of the network becomes more than 80%. In conclusion, this study shows that modeling tooth surface loss using ANNs is possible and can be achieved with a high degree of accuracy.

  14. Monte Carlo prediction of crater formation by single ion impact on solid surface

    International Nuclear Information System (INIS)

    Perez-Martin, A.M.C.; Dominguez-Vazquez, J.; Jimenez-Rodriguez, J.J.; Collins, R.; Gras-Marti, A.

    1994-01-01

    A method is presented for predicting the topography changes following the impact of one energetic ion on the plane surface of a monatomic amorphous solid. This is done in two stages. The first is a Monte Carlo calculation of the sputter yield and interior distribution relocated atoms, with no compensation for local departures from equilibrium density. In the second stage there is a systematic relaxation of the solid, in which the density returns to its previous constant value and a crater develops in the surface. Two alternative methods of carrying out stage two are compared. In the first the solid is subdivided into cells within which relaxation is carried out normal to the surface, as in previous one-dimensional studies. The second method treats the solid as a 3-dimensional incompressible medium. Both seem to reproduce quite well the main features found experimentally. (orig.)

  15. Can current moisture responses predict soil CO2 efflux under altered precipitation regimes? A synthesis of manipulation experiments

    DEFF Research Database (Denmark)

    Vicca, S.; Bahn, M.; Estiarte, M.

    2014-01-01

    dependencies of SCE. Hence, the most justified answer to the question of whether current moisture responses of SCE can be extrapolated to predict SCE under altered precipitation regimes is 'no' - as based on the most reliable data sets available. We strongly recommend that future experiments focus more...

  16. Current and future perspectives on the development, evaluation and application of in silico approaches for predicting toxicity

    Science.gov (United States)

    Safety-related problems continue to be one of the major reasons of attrition in drug development. Non-testing approaches to predict toxicity could form part of the solution. This review provides a perspective of current status of non-testing approaches available for the predictio...

  17. A novel mortality prediction model for the current population in an adult intensive care unit.

    Science.gov (United States)

    Fika, Sofia; Nanas, Serafeim; Baltopoulos, Georgios; Charitidou, Efstratia; Myrianthefs, Pavlos

    The accurate and reliable mortality prediction is very useful, in critical care medicine. There are various new variables proposed in the literature that could potentially increase the predictive ability for death in ICU of the new predictive scoring model. To develop and validate a new intensive care unit (ICU) mortality prediction model, using data that are routinely collected during the first 24 h of ICU admission, and compare its performance to the most widely used conventional scoring systems. Prospective observational study in a medical/surgical, multidisciplinary ICU, using multivariate logistic regression modeling. The new model was developed using data from a medical record review of 400 adult intensive care unit patients and was validated on a separate sample of 36 patients, to accurately predict mortality in ICU. The new model is simple, flexible and shows improved performance (ROC AUC = 0.85, SMR = 1.25), compared to the conventional scoring models (APACHE II: AUC = 0.76, SMR = 2.50, SAPS III: AUC = 0.76, SMR = 1.50), as well as higher predictive capability regarding ICU mortality (predicted mortality: 41.63 ± 31.61, observed mortality: 41.67%). The newly developed model is a quite simple risk-adjusted outcome prediction tool based on 12 routinely collected demographic and clinical variables obtained from the medical record data. It appears to be a reliable predictor of ICU mortality and is proposed for further investigation aiming at its evaluation, validation and applicability to other ICUs. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Prediction of Sea Surface Temperature Using Long Short-Term Memory

    Science.gov (United States)

    Zhang, Qin; Wang, Hui; Dong, Junyu; Zhong, Guoqiang; Sun, Xin

    2017-10-01

    This letter adopts long short-term memory(LSTM) to predict sea surface temperature(SST), which is the first attempt, to our knowledge, to use recurrent neural network to solve the problem of SST prediction, and to make one week and one month daily prediction. We formulate the SST prediction problem as a time series regression problem. LSTM is a special kind of recurrent neural network, which introduces gate mechanism into vanilla RNN to prevent the vanished or exploding gradient problem. It has strong ability to model the temporal relationship of time series data and can handle the long-term dependency problem well. The proposed network architecture is composed of two kinds of layers: LSTM layer and full-connected dense layer. LSTM layer is utilized to model the time series relationship. Full-connected layer is utilized to map the output of LSTM layer to a final prediction. We explore the optimal setting of this architecture by experiments and report the accuracy of coastal seas of China to confirm the effectiveness of the proposed method. In addition, we also show its online updated characteristics.

  19. Prediction Surface Morphology of Nanostructure Fabricated by Nano-Oxidation Technology.

    Science.gov (United States)

    Huang, Jen-Ching; Chang, Ho; Kuo, Chin-Guo; Li, Jeen-Fong; You, Yong-Chin

    2015-12-04

    Atomic force microscopy (AFM) was used for visualization of a nano-oxidation technique performed on diamond-like carbon (DLC) thin film. Experiments of the nano-oxidation technique of the DLC thin film include those on nano-oxidation points and nano-oxidation lines. The feature sizes of the DLC thin film, including surface morphology, depth, and width, were explored after application of a nano-oxidation technique to the DLC thin film under different process parameters. A databank for process parameters and feature sizes of thin films was then established, and multiple regression analysis (MRA) and a back-propagation neural network (BPN) were used to carry out the algorithm. The algorithmic results are compared with the feature sizes acquired from experiments, thus obtaining a prediction model of the nano-oxidation technique of the DLC thin film. The comparative results show that the prediction accuracy of BPN is superior to that of MRA. When the BPN algorithm is used to predict nano-point machining, the mean absolute percentage errors (MAPE) of depth, left side, and right side are 8.02%, 9.68%, and 7.34%, respectively. When nano-line machining is being predicted, the MAPEs of depth, left side, and right side are 4.96%, 8.09%, and 6.77%, respectively. The obtained data can also be used to predict cross-sectional morphology in the DLC thin film treated with a nano-oxidation process.

  20. Prediction of iodide adsorption on oxides by surface complexation modeling with spectroscopic confirmation.

    Science.gov (United States)

    Nagata, Takahiro; Fukushi, Keisuke; Takahashi, Yoshio

    2009-04-15

    A deficiency in environmental iodine can cause a number of health problems. Understanding how iodine is sequestered by materials is helpful for evaluating and developing methods for minimizing human health effects related to iodine. In addition, (129)I is considered to be strategically important for safety assessment of underground radioactive waste disposal. To assess the long-term stability of disposed radioactive waste, an understanding of (129)I adsorption on geologic materials is essential. Therefore, the adsorption of I(-) on naturally occurring oxides is of environmental concern. The surface charges of hydrous ferric oxide (HFO) in NaI electrolyte solutions were measured by potentiometric acid-base titration. The surface charge data were analyzed by means of an extended triple-layer model (ETLM) for surface complexation modeling to obtain the I(-) adsorption reaction and its equilibrium constant. The adsorption of I(-) was determined to be an outer-sphere process from ETLM analysis, which was consistent with independent X-ray absorption near-edge structure (XANES) observation of I(-) adsorbed on HFO. The adsorption equilibrium constants for I(-) on beta-TiO(2) and gamma-Al(2)O(3) were also evaluated by analyzing the surface charge data of these oxides in NaI solution as reported in the literature. Comparison of these adsorption equilibrium constants for HFO, beta-TiO(2), and gamma-Al(2)O(3) based on site-occupancy standard states permitted prediction of I(-) adsorption equilibrium constants for all oxides by means of the Born solvation theory. The batch adsorption data for I(-) on HFO and amorphous aluminum oxide were reasonably reproduced by ETLM with the predicted equilibrium constants, confirming the validity of the present approach. Using the predicted adsorption equilibrium constants, we calculated distribution coefficient (K(d)) values for I(-) adsorption on common soil minerals as a function of pH and ionic strength.

  1. Eddy heat flux across the Antarctic Circumpolar Current estimated from sea surface height standard deviation

    Science.gov (United States)

    Foppert, Annie; Donohue, Kathleen A.; Watts, D. Randolph; Tracey, Karen L.

    2017-08-01

    Eddy heat flux (EHF) is a predominant mechanism for heat transport across the zonally unbounded mean flow of the Antarctic Circumpolar Current (ACC). Observations of dynamically relevant, divergent, 4 year mean EHF in Drake Passage from the cDrake project, as well as previous studies of atmospheric and oceanic storm tracks, motivates the use of sea surface height (SSH) standard deviation, H*, as a proxy for depth-integrated, downgradient, time-mean EHF (>[EHF>¯>]) in the ACC. Statistics from the Southern Ocean State Estimate corroborate this choice and validate throughout the ACC the spatial agreement between H* and >[EHF>¯>] seen locally in Drake Passage. Eight regions of elevated >[EHF>¯>] are identified from nearly 23.5 years of satellite altimetry data. Elevated cross-front exchange usually does not span the full latitudinal width of the ACC in each region, implying a hand-off of heat between ACC fronts and frontal zones as they encounter the different >[EHF>¯>] hot spots along their circumpolar path. Integrated along circumpolar streamlines, defined by mean SSH contours, there is a convergence of ∮>[EHF>¯>] in the ACC: 1.06 PW enters from the north and 0.02 PW exits to the south. Temporal trends in low-frequency [EHF] are calculated in a running-mean sense using H* from overlapping 4 year subsets of SSH. Significant increases in downgradient [EHF] magnitude have occurred since 1993 at Kerguelen Plateau, Southeast Indian Ridge, and the Brazil-Malvinas Confluence, whereas the other five >[EHF>¯>] hot spots have insignificant trends of varying sign.

  2. Prediction of lateral surface, volume and sphericity of pomegranate using MLP artificial neural network

    Directory of Open Access Journals (Sweden)

    A Rohani

    2015-09-01

    Full Text Available Introduction: Fast and accurate determination of geometrical properties of agricultural products has many applications in agricultural operations like planting, cultivating, harvesting and post-harvesting. Calculations related to storing, shipping and storage-coating materials as well as peeling time and surface-microbial concentrations are some applications of estimating product volume and surface area. Sphericity is also a parameter by which the shape differences between fruits, vegetables, grains and seeds can be quantified. This parameter is important in grading systems and inspecting rolling capability of agricultural products. Bayram presented a new dimensional method and equation to calculate the sphericity of certain shapesand some granular food materials (Bayram, 2005. Kumar and Mathew proposed atheoretically soundmethod for estimating the surface area of ellipsoidal food materials (Kumar and Mathew, 2003. Clayton et al. used non-linear regression models for calculation of apple surface area using the fruit mass or volume (Clayton et al., 1995. Humeida and Hobani predicted surface area and volume of pomegranates based on the weight and geometrical diametermean (Humeida and Hobani, 1993. Wang and Nguang designeda low cost sensor system to automatically compute the volume and surface area of axi-symmetricagricultural products such as eggs, lemons, limes and tamarillos (Wang and Nguang, 2007. The main objective of this study was to investigate the potential of Artificial Neural Network (ANN technique as an alternative method to predict the volume, surface area and sphericity of pomegranates. Materials and methods: The water displacement method (WDM was used for measuring the actual volume of pomegranates. Also, the sphericity and surface area are computed by using analytical methods. In this study, the neural MLP models were designed based upon the three nominal diameters of pomegranatesas variable inputs, while the output model consisted

  3. Computational prediction of heat transfer to gas turbine nozzle guide vanes with roughened surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Guo, S.M.; Jones, T.V. [Univ. of Oxford (United Kingdom). Dept. of Engineering Science; Lock, G.D. [Univ. of Bath (United Kingdom). Dept. of Mechanical Engineering; Dancer, S.N. [Rolls-Royce PLC, Derby (United Kingdom)

    1998-04-01

    The local Mach number and heat transfer coefficient over the aerofoil surfaces and endwalls of a transonic gas turbine nozzle guide vane have been calculated. the computations were performed by solving the time-averaged Navier-Stokes equations using a fully three-dimensional computational code (CFDS), which is well established at Rolls-Royce. A model to predict the effects of roughness has been incorporated into CFDS and heat transfer levels have been calculated for both hydraulically smooth and transitionally rough surfaces. The roughness influences the calculations in two ways; first the mixing length at a certain height above the surface is increased; second the wall function used to reconcile the wall condition with the first grid point above the wall is also altered. The first involves a relatively straightforward shift of the origin in the van Driest damping function description, the second requires an integration of the momentum equation across the wall layer. A similar treatment applies to the energy equation. The calculations are compared with experimental contours of heat transfer coefficient obtained using both thin-film gages and the transient liquid crystal technique. Measurements were performed using both hydraulically smooth and roughened surfaces, and at engine-representative Mach and Reynolds numbers. The heat transfer results are discussed and interpreted in terms of surface-shear flow visualization using oil and dye techniques.

  4. Surface energy balances of three general circulation models: Current climate and response to increasing atmospheric CO2

    International Nuclear Information System (INIS)

    Gutowski, W.J.; Gutzler, D.S.; Portman, D.; Wang, W.C.

    1988-04-01

    The surface energy balance simulated by state-of-the-art general circulation models at GFDL, GISS and NCAR for climates with current levels of atmospheric CO 2 concentration (control climate) and with twice the current levels. The work is part of an effort sponsored by the US Department of Energy to assess climate simulations produced by these models. The surface energy balance enables us to diagnose differences between models in surface temperature climatology and sensitivity to doubling CO 2 in terms of the processes that control surface temperature. Our analysis compares the simulated balances by averaging the fields of interest over a hierarchy of spatial domains ranging from the entire globe down to regions a few hundred kilometers across

  5. Predicting the effect of surface texture on the qualitative form of prehension.

    Directory of Open Access Journals (Sweden)

    Ian John Flatters

    Full Text Available Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, medium-friction and low-friction and one of three widths (50 mm, 70 mm and 90 mm. Each object was placed at three distances (100 mm, 300 mm and 500 mm, representing a total of 27 trial conditions. We observed two distinct movement patterns across all trials--participants either: (i brought their arm to a stop, secured the object and lifted it from the tabletop; or (ii grasped the object 'on-the-fly', so it was secured in the hand while the arm was moving. A majority of grasps were on-the-fly when the texture was high-friction and none when the object was low-friction, with medium-friction producing an intermediate proportion. Previous research has shown that the probability of on-the-fly behaviour is a function of grasp surface accuracy constraints. A finger friction rig was used to calculate the coefficients of friction for the objects and these calculations showed that the area available for a stable grasp (the 'functional grasp surface size' increased with surface friction coefficient. Thus, knowledge of functional grasp surface size is required to predict the probability of observing a given qualitative form of grasping in human prehensile behaviour.

  6. Predicting the effect of surface texture on the qualitative form of prehension.

    Science.gov (United States)

    Flatters, Ian John; Otten, Loanne; Witvliet, Anna; Henson, Brian; Holt, Raymond John; Culmer, Pete; Bingham, Geoffrey Parker; Wilkie, Richard McGilchrist; Mon-Williams, Mark

    2012-01-01

    Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, medium-friction and low-friction) and one of three widths (50 mm, 70 mm and 90 mm). Each object was placed at three distances (100 mm, 300 mm and 500 mm), representing a total of 27 trial conditions. We observed two distinct movement patterns across all trials--participants either: (i) brought their arm to a stop, secured the object and lifted it from the tabletop; or (ii) grasped the object 'on-the-fly', so it was secured in the hand while the arm was moving. A majority of grasps were on-the-fly when the texture was high-friction and none when the object was low-friction, with medium-friction producing an intermediate proportion. Previous research has shown that the probability of on-the-fly behaviour is a function of grasp surface accuracy constraints. A finger friction rig was used to calculate the coefficients of friction for the objects and these calculations showed that the area available for a stable grasp (the 'functional grasp surface size') increased with surface friction coefficient. Thus, knowledge of functional grasp surface size is required to predict the probability of observing a given qualitative form of grasping in human prehensile behaviour.

  7. Amplification of surface acoustic waves by transverse electric current in piezoelectric semiconductors

    DEFF Research Database (Denmark)

    Gulyaev, Yuri V.

    1974-01-01

    It is shown that the principal characteristic feature of the surface acoustic waves in piezoelectrics—the presence of an alternating electric field transverse to the surface, which can be of the same order of magnitude as the longitudinal field—may not only give rise to the known transverse...... acoustoelectric effect but also lead to amplification of surface acoustic waves by electron drift perpendicular to the surface. For Love waves in a piezoelectric semiconductor film on a highly conducting substrate, the amplification coefficient is found and the conditions necessary for amplification...

  8. Improving weather predictability by including land-surface model parameter uncertainty

    Science.gov (United States)

    Orth, Rene; Dutra, Emanuel; Pappenberger, Florian

    2016-04-01

    The land surface forms an important component of Earth system models and interacts nonlinearly with other parts such as ocean and atmosphere. To capture the complex and heterogenous hydrology of the land surface, land surface models include a large number of parameters impacting the coupling to other components of the Earth system model. Focusing on ECMWF's land-surface model HTESSEL we present in this study a comprehensive parameter sensitivity evaluation using multiple observational datasets in Europe. We select 6 poorly constrained effective parameters (surface runoff effective depth, skin conductivity, minimum stomatal resistance, maximum interception, soil moisture stress function shape, total soil depth) and explore their sensitivity to model outputs such as soil moisture, evapotranspiration and runoff using uncoupled simulations and coupled seasonal forecasts. Additionally we investigate the possibility to construct ensembles from the multiple land surface parameters. In the uncoupled runs we find that minimum stomatal resistance and total soil depth have the most influence on model performance. Forecast skill scores are moreover sensitive to the same parameters as HTESSEL performance in the uncoupled analysis. We demonstrate the robustness of our findings by comparing multiple best performing parameter sets and multiple randomly chosen parameter sets. We find better temperature and precipitation forecast skill with the best-performing parameter perturbations demonstrating representativeness of model performance across uncoupled (and hence less computationally demanding) and coupled settings. Finally, we construct ensemble forecasts from ensemble members derived with different best-performing parameterizations of HTESSEL. This incorporation of parameter uncertainty in the ensemble generation yields an increase in forecast skill, even beyond the skill of the default system. Orth, R., E. Dutra, and F. Pappenberger, 2016: Improving weather predictability by

  9. Utilization of Hydrologic Remote Sensing Data in Land Surface Modeling and Data Assimilation: Current Status and Challenges

    Science.gov (United States)

    Kumar, Sujay V.; Peters-Lidard, Christa; Reichl, Rolf; Harrison, Kenneth; Santanello, Joseph

    2010-01-01

    Recent advances in remote sensing technologies have enabled the monitoring and measurement of the Earth's land surface at an unprecedented scale and frequency. The myriad of these land surface observations must be integrated with the state-of-the-art land surface model forecasts using data assimilation to generate spatially and temporally coherent estimates of environmental conditions. These analyses are of critical importance to real-world applications such as agricultural production, water resources management and flood, drought, weather and climate prediction. This need motivated the development of NASA Land Information System (LIS), which is an expert system encapsulating a suite of modeling, computational and data assimilation tools required to address challenging hydrological problems. LIS integrates the use of several community land surface models, use of ground and satellite based observations, data assimilation and uncertainty estimation techniques and high performance computing and data management tools to enable the assessment and prediction of hydrologic conditions at various spatial and temporal scales of interest. This presentation will focus on describing the results, challenges and lessons learned from the use of remote sensing data for improving land surface modeling, within LIS. More specifically, studies related to the improved estimation of soil moisture, snow and land surface temperature conditions through data assimilation will be discussed. The presentation will also address the characterization of uncertainty in the modeling process through Bayesian remote sensing and computational methods.

  10. Assessing Confidence in Pliocene Sea Surface Temperatures to Evaluate Predictive Models

    Science.gov (United States)

    Dowsett, Harry J.; Robinson, Marci M.; Haywood, Alan M.; Hill, Daniel J.; Dolan, Aisling. M.; Chan, Wing-Le; Abe-Ouchi, Ayako; Chandler, Mark A.; Rosenbloom, Nan A.; Otto-Bliesner, Bette L.; hide

    2012-01-01

    In light of mounting empirical evidence that planetary warming is well underway, the climate research community looks to palaeoclimate research for a ground-truthing measure with which to test the accuracy of future climate simulations. Model experiments that attempt to simulate climates of the past serve to identify both similarities and differences between two climate states and, when compared with simulations run by other models and with geological data, to identify model-specific biases. Uncertainties associated with both the data and the models must be considered in such an exercise. The most recent period of sustained global warmth similar to what is projected for the near future occurred about 3.33.0 million years ago, during the Pliocene epoch. Here, we present Pliocene sea surface temperature data, newly characterized in terms of level of confidence, along with initial experimental results from four climate models. We conclude that, in terms of sea surface temperature, models are in good agreement with estimates of Pliocene sea surface temperature in most regions except the North Atlantic. Our analysis indicates that the discrepancy between the Pliocene proxy data and model simulations in the mid-latitudes of the North Atlantic, where models underestimate warming shown by our highest-confidence data, may provide a new perspective and insight into the predictive abilities of these models in simulating a past warm interval in Earth history.This is important because the Pliocene has a number of parallels to present predictions of late twenty-first century climate.

  11. Assessing confidence in Pliocene sea surface temperatures to evaluate predictive models

    Science.gov (United States)

    Dowsett, Harry J.; Robinson, Marci M.; Haywood, Alan M.; Hill, Daniel J.; Dolan, Aisling M.; Stoll, Danielle K.; Chan, Wing-Le; Abe-Ouchi, Ayako; Chandler, Mark A.; Rosenbloom, Nan A.; Otto-Bliesner, Bette L.; Bragg, Fran J.; Lunt, Daniel J.; Foley, Kevin M.; Riesselman, Christina R.

    2012-01-01

    In light of mounting empirical evidence that planetary warming is well underway, the climate research community looks to palaeoclimate research for a ground-truthing measure with which to test the accuracy of future climate simulations. Model experiments that attempt to simulate climates of the past serve to identify both similarities and differences between two climate states and, when compared with simulations run by other models and with geological data, to identify model-specific biases. Uncertainties associated with both the data and the models must be considered in such an exercise. The most recent period of sustained global warmth similar to what is projected for the near future occurred about 3.3–3.0 million years ago, during the Pliocene epoch. Here, we present Pliocene sea surface temperature data, newly characterized in terms of level of confidence, along with initial experimental results from four climate models. We conclude that, in terms of sea surface temperature, models are in good agreement with estimates of Pliocene sea surface temperature in most regions except the North Atlantic. Our analysis indicates that the discrepancy between the Pliocene proxy data and model simulations in the mid-latitudes of the North Atlantic, where models underestimate warming shown by our highest-confidence data, may provide a new perspective and insight into the predictive abilities of these models in simulating a past warm interval in Earth history. This is important because the Pliocene has a number of parallels to present predictions of late twenty-first century climate.

  12. Variational assimilation of land surface temperature observations for enhanced river flow predictions

    Science.gov (United States)

    Ercolani, Giulia; Castelli, Fabio

    2016-04-01

    Data assimilation (DA) has the potential of improving hydrologic forecasts. However, many issues arise in case it is employed for spatially distributed hydrologic models that describes processes in various compartments: large dimensionality of the inverse problem, layers governed by different equations, non-linear and discontinuous model structure, complex topology of domains such as surface drainage and river network.On the other hand, integrated models offer the possibility of improving prediction of specific states by exploiting observations of quantities belonging to other compartments. In terms of forecasting river discharges, and hence for their enhancement, soil moisture is a key variable, since it determines the partitioning of rainfall into infiltration and surface runoff. However, soil moisture measurements are affected by issues that could prevent a successful DA and an actual improvement of discharge predictions.In-situ measurements suffer a dramatic spatial scarcity, while observations from satellite are barely accurate and provide spatial information only at a very coarse scale (around 40 km).Hydrologic models that explicitly represent land surface processes of coupled water and energy balance provide a valid alternative to direct DA of soil moisture.They gives the possibility of inferring soil moisture states through DA of remotely sensed Land Surface Temperature (LST), whose measurements are more accurate and with a higher spatial resolution in respect to those of soil moisture. In this work we present the assimilation of LST data in a hydrologic model (Mobidic) that is part of the operational forecasting chain for the Arno river, central Italy, with the aim of improving flood predictions. Mobidic is a raster based, continuous in time and distributed in space hydrologic model, with coupled mass and energy balance at the surface and coupled groundwater and surface hydrology. The variational approach is adopted for DA, since it requires less

  13. Surface and subsurface geostrophic current variability in the Indian Ocean from altimetry

    Digital Repository Service at National Institute of Oceanography (India)

    Cadden, D.D; Subrahmanyam, B; Chambers, D; Murty, V.S.N.

    the World Ocean Atlas 2005. The results of this method were validated with currents measured using Acoustic Doppler Current Profilers moored along the equator at 77 degrees E, 83 degrees E, and 93 degrees E. The measured and computed currents compared...

  14. Predicting the impact of vegetations in open channels with different distributaries' operations on water surface profile using artificial neural networks

    International Nuclear Information System (INIS)

    Abdeen, Mostafa A. M.

    2008-01-01

    Most of the open water irrigation channels in Egypt suffer from the infestation of aquatic weeds, especially the submerged ones that cause numerous hydraulic problems for the open channels themselves and their water distributaries such as increasing water losses, obstructing water flow, and reducing channels' water distribution efficiencies. Accurate simulation and prediction of flow behavior in such channels is very essential for water distribution decision makers. Artificial neural networks (ANN) have proven to be very successful in the simulation of several physical phenomena, in general, and in the water research field in particular. Therefore, the current study aims towards introducing the utilization of ANN in simulating the impact of vegetation in main open channel, which supplies water to different distributaries, on the water surface profile in this main channel. Specifically, the study, presented in the current paper utilizes ANN technique for the development of various models to simulate the impact of different submerged weeds' densities, different flow discharges, and different distributaries operation scheduling on the water surface profile in an experimental main open channel that supplies water to different distributaries. In the investigated experiment, the submerged weeds were simulated as branched flexible elements. The investigated experiment was considered as an example for implementing the same methodology and technique in a real open channel system. The results showed that the ANN technique is very successful in simulating the flow behavior of the pre-mentioned open channel experiment with the existence of the submerged weeds. In addition, the developed ANN models were capable of predicting the open channel flow behavior in all the submerged weeds' cases that were considered in the ANN development process

  15. Retrieving near surface soil moisture from microwave radiometric observations: current status and future plans.

    NARCIS (Netherlands)

    Wigneron, J.P.; Calvet, J.C.; Pellarin, T.; vd Griend, A.A.; Berger, M.; Ferrazzoli, P.

    2003-01-01

    Surface soil moisture is a key variable used to describe water and energy exchanges at the land surface/atmosphere interface. Passive microwave remotely sensed data have great potential for providing estimates of soil moisture with good temporal repetition on a daily basis and on a regional scale (∼

  16. Current status of mammalian and human models for predicting drug photosensitivity

    International Nuclear Information System (INIS)

    Harber, L.C.

    1981-01-01

    The status of efforts to develop experimental models for drug photosensitivity reactions in small mammals is reviewed. Tests which are practical and also have a high predictive value in determining photosensitivity hazards to man are the goal of this research. The various animal model systems which have been used are evaluated with respect to these goals

  17. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2011-01-01

    The widely used cascade speed and torque controllers have a limited control performance in most high power applications due to the low switching frequency of power electronic converters and the convenience to avoid speed overshoots and oscillations for lifetime considerations. Model Predictive...

  18. Fatigue Life Prediction in Rapid Die Casting - Preliminary Work in View of Current Research

    International Nuclear Information System (INIS)

    Chuan Huat Ng; Grote, Karl-Heinrich; Baehr, Ruediger

    2007-01-01

    Numerical simulation technique as a prediction tool is slowly adopted in metal casting industry for predicting design modelling solidification analysis. The reasons for this activity is found in the need to further enhance the geometrical design and mechanical properties of the tool design and the correct prediction methodology to fulfil industrial needs. The present state of numerical simulation capabilities in rapid die casting technologies is reviewed and the failure mode mechanisms of thermal fatigue, aimed at developing a numerical simulation with a systematic design guidance for predicting the thermal cyclic loading analysis and improvement is presented along with several other methods. The economic benefits of a numerical simulation technique in die casting are limited to tool life time, mechanical properties and design guidance. The extensive computer capabilities of a numerical simulation with a systematic design guidance methodology are exploited to provide a solution for flexible design, mechanical properties and mould life time. Related research carried out worldwide by different organisations and academic institutions are discussed

  19. The current and future use of ridge regression for prediction in quantitative genetics

    NARCIS (Netherlands)

    R. de Vlaming (Ronald); P.J.F. Groenen (Patrick)

    2015-01-01

    textabstractIn recent years, there has been a considerable amount of research on the use of regularization methods for inference and prediction in quantitative genetics. Such research mostly focuses on selection of markers and shrinkage of their effects. In this review paper, the use of ridge

  20. The Current and Future Use of Ridge Regression for Prediction in Quantitative Genetics

    NARCIS (Netherlands)

    de Vlaming, R.; Groenen, P.J.F.

    2015-01-01

    In recent years, there has been a considerable amount of research on the use of regularization methods for inference and prediction in quantitative genetics. Such research mostly focuses on selection of markers and shrinkage of their effects. In this review paper, the use of ridge regression for

  1. Applying machine learning to predict patient-specific current CD 4 ...

    African Journals Online (AJOL)

    ... respectively, proving that a CD4 cell count measure may be accurately predicted using machine learning on genotype, viral load and time. Keywords: Human immunodeficiency virus (HIV), antigens, CD4, computational biology, artificial intelligence, data mining, pattern recognition. African Journal of Biotechnology Vol.

  2. Few thoughts on Mixing and Entrainment of Lock-Release Turbulent Dense Currents over Rough-Surfaces

    Science.gov (United States)

    Bhaganaagar, Kiran; NaraSimhaRao, Pavan

    2017-04-01

    Buoyancy driven density currents are the result of the intense turbulence exchanges that occur due to interaction of dense waters with surrounding ambient and calm waters in the ocean. E.g. in the basins of the Arctic continent shelves highly energetic and dissipative density current form due to mixing of cold, dense brine-enriched shelf waters with ambient lighter waters. Intense turbulence causes mixing, the mixed water mass descends down the continental slope. The eventual properties of the mixed water will dictate the deep-water mass. Hence, entrainment/mixing processes are central to oceanic thermohaline circulation. In spite of its importance, the entrainment and the mixing they undergo with overlying water is still not clear. In this talk, we focus on overcoming the challenges in calculating the entrainment over rough-surfaces. The analysis is conducted on lock-release density currents. A highly accurate direct numerical simulation and large eddy simulation solvers have been developed to simulate dense currents over range of rough-surfaces. A new method has been developed to calculate mixing in the head of the density-currents using principles of height-averaged density method. The results have revealed the shape of roughness elements and the standard deviation of the roughness height are the important metrics that influence the front velocity and front characteristics. Entrainment is significant in the head region of dense currents over uniform roughness, whereas for non-uniform rough surfaces, entrainment occurs throughout the current. These results have important implications in our current understanding of mixing in head region of the density current. Further, a relation has been established between the wall-shear stress and entrainment, and this has resulted in a new parameterization of the entrainment as function of the roughness metrics. This study will of be important consequence in improving the accuracy of parameterization of density currents in

  3. Predicting wettability behavior of fluorosilica coated metal surface using optimum neural network

    Science.gov (United States)

    Taghipour-Gorjikolaie, Mehran; Valipour Motlagh, Naser

    2018-02-01

    The interaction between variables, which are effective on the surface wettability, is very complex to predict the contact angles and sliding angles of liquid drops. In this paper, in order to solve this complexity, artificial neural network was used to develop reliable models for predicting the angles of liquid drops. Experimental data are divided into training data and testing data. By using training data and feed forward structure for the neural network and using particle swarm optimization for training the neural network based models, the optimum models were developed. The obtained results showed that regression index for the proposed models for the contact angles and sliding angles are 0.9874 and 0.9920, respectively. As it can be seen, these values are close to unit and it means the reliable performance of the models. Also, it can be inferred from the results that the proposed model have more reliable performance than multi-layer perceptron and radial basis function based models.

  4. 3D transient model to predict temperature and ablated areas during laser processing of metallic surfaces

    Directory of Open Access Journals (Sweden)

    Babak. B. Naghshine

    2017-02-01

    Full Text Available Laser processing is one of the most popular small-scale patterning methods and has many applications in semiconductor device fabrication and biomedical engineering. Numerical modelling of this process can be used for better understanding of the process, optimization, and predicting the quality of the final product. An accurate 3D model is presented here for short laser pulses that can predict the ablation depth and temperature distribution on any section of the material in a minimal amount of time. In this transient model, variations of thermal properties, plasma shielding, and phase change are considered. Ablation depth was measured using a 3D optical profiler. Calculated depths are in good agreement with measured values on laser treated titanium surfaces. The proposed model can be applied to a wide range of materials and laser systems.

  5. Dynamical seasonal prediction of summer sea surface temperatures in the Great Barrier Reef

    Science.gov (United States)

    Spillman, C. M.; Alves, O.

    2009-03-01

    Coral bleaching is a serious problem threatening the world coral reef systems, triggered by high sea surface temperatures (SST) which are becoming more prevalent as a result of global warming. Seasonal forecasts from coupled ocean-atmosphere models can be used to predict anomalous SST months in advance. In this study, we assess the ability of the Australian Bureau of Meteorology seasonal forecast model (POAMA) to forecast SST anomalies in the Great Barrier Reef, Australia, with particular focus on the major 1998 and 2002 bleaching events. Advance warning of potential bleaching events allows for the implementation of management strategies to minimise reef damage. This study represents the first attempt to apply a dynamical seasonal model to the problem of coral bleaching and predict SST over a reef system for up to 6 months lead-time, a potentially invaluable tool for reef managers.

  6. Development of a new mathematical model for prediction of surface subsidence due to inclined coal-seam mining

    Energy Technology Data Exchange (ETDEWEB)

    Asadi, A.; Shahriar, K.; Goshtasbi, K.; Najm, K. [Islam Azad University, Tehran (Iran). Dept. of Mining Engineering

    2005-01-01

    Subsidence phenomenon as an unwanted consequence of underground mining can cause problems for environment and surface structures in mine area. Surface subsidence prediction for inclined and steep seams has been given less attention than horizontal seams due to the difficulties involved in the extraction of such coal-seams. This paper introduces a new profile function method for prediction of surface subsidence due to inclined coal-seam mining. The results of calculation with the new function indicate that the predicted value has good agreement with the measured data.

  7. Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M Mohan; Gorin, Alexander [School of Engineering and Science, Curtin University of Technology, Sarawak (Malaysia); Abou-El-Hossein, K A, E-mail: mohan.m@curtin.edu.my [Mechanical and Aeronautical Department, Nelson Mandela Metropolitan University, Port Elegebeth, 6031 (South Africa)

    2011-02-15

    Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

  8. Prediction of the adhesive behavior of bio-inspired functionally graded materials against rough surfaces

    Directory of Open Access Journals (Sweden)

    Chen Peijian

    2014-06-01

    Full Text Available Roughness effect and adhesion properties are important characteristics to be accessed in the development of functionally graded materials for biological and biomimetic applications, particularly for the hierarchical composition in biomimetic gecko robot. A multi-asperities adhesion model to predict the adhesive forces is presented in this work. The effect of surface roughness and graded material properties, which significantly alter the adhesive strength between contact bodies, can be simultaneously considered in the generalized model. It is found that proper interfacial strength can be controlled by adjusting surface roughness σ / R, graded exponent k and material parameter E*R / Δγ. The results should be helpful in the design of new biomimetic materials and useful in application of micro functional instruments.

  9. Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

    International Nuclear Information System (INIS)

    Reddy, M Mohan; Gorin, Alexander; Abou-El-Hossein, K A

    2011-01-01

    Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

  10. A probabilistic method for the estimation of ocean surface currents from short time series of HF radar data

    Science.gov (United States)

    Guérin, Charles-Antoine; Grilli, Stéphan T.

    2018-01-01

    We present a new method for inverting ocean surface currents from beam-forming HF radar data. In contrast with the classical method, which inverts radial currents based on shifts of the main Bragg line in the radar Doppler spectrum, the method works in the temporal domain and inverts currents from the amplitude modulation of the I and Q radar time series. Based on this principle, we propose a Maximum Likelihood approach, which can be combined with a Bayesian inference method assuming a prior current distribution, to infer values of the radial surface currents. We assess the method performance by using synthetic radar signal as well as field data, and systematically comparing results with those of the Doppler method. The new method is found advantageous for its robustness to noise at long range, its ability to accommodate shorter time series, and the possibility to use a priori information to improve the estimates. Limitations are related to current sign errors at far-ranges and biased estimates for small current values and very short samples. We apply the new technique to a data set from a typical 13.5 MHz WERA radar, acquired off of Vancouver Island, BC, and show that it can potentially improve standard synoptic current mapping.

  11. Biological and environmental surface interactions of nanomaterials: characterization, modeling, and prediction.

    Science.gov (United States)

    Chen, Ran; Riviere, Jim E

    2017-05-01

    The understanding of nano-bio interactions is deemed essential in the design, application, and safe handling of nanomaterials. Proper characterization of the intrinsic physicochemical properties, including their size, surface charge, shape, and functionalization, is needed to consider the fate or impact of nanomaterials in biological and environmental systems. The characterizations of their interactions with surrounding chemical species are often hindered by the complexity of biological or environmental systems, and the drastically different surface physicochemical properties among a large population of nanomaterials. The complexity of these interactions is also due to the diverse ligands of different chemical properties present in most biomacromolecules, and multiple conformations they can assume at different conditions to minimize their conformational free energy. Often these interactions are collectively determined by multiple physical or chemical forces, including electrostatic forces, hydrogen bonding, and hydrophobic forces, and calls for multidimensional characterization strategies, both experimentally and computationally. Through these characterizations, the understanding of the roles surface physicochemical properties of nanomaterials and their surface interactions with biomacromolecules can play in their applications in biomedical and environmental fields can be obtained. To quantitatively decipher these physicochemical surface interactions, computational methods, including physical, statistical, and pharmacokinetic models, can be used for either analyses of large amounts of experimental characterization data, or theoretical prediction of the interactions, and consequent biological behavior in the body after administration. These computational methods include molecular dynamics simulation, structure-activity relationship models such as biological surface adsorption index, and physiologically-based pharmacokinetic models. WIREs Nanomed Nanobiotechnol 2017

  12. Translation of Land Surface Model Accuracy and Uncertainty into Coupled Land-Atmosphere Prediction

    Science.gov (United States)

    Santanello, Joseph A.; Kumar, Sujay; Peters-Lidard, Christa D.; Harrison, Kenneth W.; Zhou, Shuija

    2012-01-01

    Land-atmosphere (L-A) Interactions playa critical role in determining the diurnal evolution of both planetary boundary layer (PBL) and land surface heat and moisture budgets, as well as controlling feedbacks with clouds and precipitation that lead to the persistence of dry and wet regimes. Recent efforts to quantify the strength of L-A coupling in prediction models have produced diagnostics that integrate across both the land and PBL components of the system. In this study, we examine the impact of improved specification of land surface states, anomalies, and fluxes on coupled WRF forecasts during the summers of extreme dry (2006) and wet (2007) land surface conditions in the U.S. Southern Great Plains. The improved land initialization and surface flux parameterizations are obtained through the use of a new optimization and uncertainty estimation module in NASA's Land Information System (US-OPT/UE), whereby parameter sets are calibrated in the Noah land surface model and classified according to a land cover and soil type mapping of the observation sites to the full model domain. The impact of calibrated parameters on the a) spinup of the land surface used as initial conditions, and b) heat and moisture states and fluxes of the coupled WRF Simulations are then assessed in terms of ambient weather and land-atmosphere coupling along with measures of uncertainty propagation into the forecasts. In addition, the sensitivity of this approach to the period of calibration (dry, wet, average) is investigated. Finally, tradeoffs of computational tractability and scientific validity, and the potential for combining this approach with satellite remote sensing data are also discussed.

  13. Surface circulation in the Iroise Sea (western Brittany) derived from high resolution current mapping by HF radars

    Science.gov (United States)

    Sentchev, Alexei; Forget, Philippe; Barbin, Yves; Marié, Louis; Ardhuin, Fabrice

    2010-05-01

    The use of high frequency radar (HFR) systems for near-real-time coastal ocean monitoring necessities that short time scale motions of the radar-derived velocities are better understood. While the ocean radar systems are able to describe coastal flow patterns with unprecedented details, the data they produce are often too sparse or gappy for applications such as the identification of coherent structures and fronts or understanding transport and mixing processes. In this study, we address two challenges. First, we report results from the HF radar system (WERA) which is routinely operating since 2006 on the western Brittany coast to monitor surface circulation in the Iroise Sea, over an area extending up to 100 km offshore. To obtain more reliable records of vector current fields at high space and time resolution, the Multiple Signal Classification (MUSIC) direction finding algorithm is employed in conjunction with the variational interpolation (2dVar) of radar-derived velocities. This provides surface current maps at 1 km spacing and time resolution of 20 min. Removing the influence of the sea state on radar-derived current measurements is discussed and performed on some data sequences. Second, we examine in deep continuous 2d velocity records for a number of periods, exploring the different modes of variability of surface currents in the region. Given the extent, duration, and resolution of surface current velocity measurements, new quantitative insights from various time series and spatial analysis on higher frequency kinematics will be discussed. By better characterizing the full spectrum of flow regimes that contribute to the surface currents and their shears, a more complete picture of the circulation in the Iroise Sea can be obtained.

  14. Behavior of AC High Voltage Polyamide Insulators: Evolution of Leakage Current in Different Surface Conditions

    Directory of Open Access Journals (Sweden)

    Mohammed El Amine Slama

    2015-01-01

    Full Text Available This paper is aimed at a systematic study of the leakage current of high voltage polyamide insulator string under different conditions of pollution for possible application in the electric locomotive systems. It is shown that in the case of clean/dry and clean/wetted insulators, the leakage current and applied voltage are linear. While in the case of pollution with saline spray, the leakage current and the applied voltage are not linear; the leakage current changes from a linear regime to a nonlinear regime up to total flashover of the insulators sting. Traces of erosion and tracking of insulators resulting of partial discharges are observed.

  15. Testing the current paradigm for space weather prediction with heliospheric imagers

    Science.gov (United States)

    Barnard, Luke A.; de Koning, Curt A.; Scott, Christopher J.; Owens, Mathew J.; Wilkinson, Julia; Davies, Jackie A.

    2017-06-01

    Predictions of the arrival of four coronal mass ejections (CMEs) in geospace are produced through use of three CME geometric models combined with CME drag modeling, constraining these models with the available Coronagraph and Heliospheric Imager data. The efficacy of these predications is assessed by comparison with the Space Weather Prediction Center (SWPC) numerical MHD forecasts of these same events. It is found that such a prediction technique cannot outperform the standard SWPC forecast at a statistically meaningful level. We test the Harmonic Mean, Self-Similar Expansion, and Ellipse Evolution geometric models, and find that, for these events at least, the differences between the models are smaller than the observational errors. We present a new method of characterizing CME fronts in the Heliospheric Imager field of view, utilizing the analysis of citizen scientists working with the Solar Stormwatch project, and we demonstrate that this provides a more accurate representation of the CME front than is obtained by experts analyzing elongation time maps for the studied events. Comparison of the CME kinematics estimated independently from the STEREO-A and STEREO-B Heliospheric Imager data reveals inconsistencies that cannot be explained within the observational errors and model assumptions. We argue that these observations imply that the assumptions of the CME geometric models are routinely invalidated and question their utility in a space weather forecasting context. These results argue for the continuing development of more advanced techniques to better exploit the Heliospheric Imager observations for space weather forecasting.

  16. Calibration and Validation of High Frequency Radar for Ocean Surface Current Mapping

    National Research Council Canada - National Science Library

    Kim, Kyung

    2004-01-01

    High Frequency (HF) radar backscatter instruments are being developed and tested in the marine science and defense science communities for their abilities to sense surface parameters remotely in the coastal ocean over large areas...

  17. An Investigation of Surface Current Patterns Related to Upwelling in Monterey Bay, Using High Frequency Radar

    National Research Council Canada - National Science Library

    Enriquez, Andres

    2004-01-01

    High Frequency (HF) radar backscatter instruments are under development and testing in the marine science and defense science communities for their abilities to remotely sense surface parameters in the coastal ocean over large areas...

  18. Behavioral response of cave and surface Asellus aquaticus to water current

    OpenAIRE

    Dacar, Maja

    2017-01-01

    There are many questions regarding what influences the emergence of new species. Firstly and above all, is the appearance of differences within a certain specie, where a certain part is isolated from the group and continues its own evolution. One of these differences appear between the surface- and cave-dwelling Asellus aquaticus, as the ability to hold on to their surface. The discovery of these differences was carried out using a method of experiment, namely on the cave-dwelling Asellus ...

  19. THE DYNAMIC INTERACTION OF THE MOVING CONTACTING SURFACES AT THE EXAMPLE OF THE ELECTRIC ROLLING STOCK CURRENT COLLECTOR

    Directory of Open Access Journals (Sweden)

    M. O. Babiak

    2009-07-01

    Full Text Available The process of mutual moving and contacting of surfaces of current collecting pantograph elements and contact network is considered taking into account the particularities of inf1uence of speed and acceleration parameters, determination of which will allow to forecast mathematically the wear-out degree of contacting elements.

  20. Comparison of Regression and Artificial Neural Network Models for Surface Roughness Prediction with the Cutting Parameters in CNC Turning

    Directory of Open Access Journals (Sweden)

    Muammer Nalbant

    2007-06-01

    Full Text Available Surface roughness, an indicator of surface quality, is one of the most specified customer requirements in machining of parts. In this study, the experimental results corresponding to the effects of different insert nose radii of cutting tools (0.4, 0.8, 1.2 mm, various depth of cuts (0.75, 1.25, 1.75, 2.25, 2.75 mm, and different feedrates (100, 130, 160, 190, 220 mm/min on the surface quality of the AISI 1030 steel workpieces have been investigated using multiple regression analysis and artificial neural networks (ANN. Regression analysis and neural network-based models used for the prediction of surface roughness were compared for various cutting conditions in turning. The data set obtained from the measurements of surface roughness was employed to and tests the neural network model. The trained neural network models were used in predicting surface roughness for cutting conditions. A comparison of neural network models with regression model was carried out. Coefficient of determination was 0.98 in multiple regression model. The scaled conjugate gradient (SCG model with 9 neurons in hidden layer has produced absolute fraction of variance (R2 values of 0.999 for the training data, and 0.998 for the test data. Predictive neural network model showed better predictions than various regression models for surface roughness. However, both methods can be used for the prediction of surface roughness in turning.

  1. Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion

    DEFF Research Database (Denmark)

    Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

    2016-01-01

    BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atri...

  2. Predictive Pulse Pattern Current Modulation Scheme for Harmonic Reduction in Three-Phase Multidrive Systems

    DEFF Research Database (Denmark)

    Davari, Pooya; Yang, Yongheng; Zare, Firuz

    2016-01-01

    at the rectification stage to synthesize sinusoidal input currents. The input voltage sensing is avoided in order to minimize the number of required sensors, and the grid synchronization also has been implemented based on a common Phase-Locked-Loop (PLL) using the DC-link capacitor voltage ripple. Experimental results...

  3. Interleaved Buck Converter with Variable Number of Active Phases and a Predictive Current Sharing Scheme

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Garcia, O.; Oliver, J. A.

    2008-01-01

    The efficiency of an interleaved Buck converter is typically low at light load conditions because of the switching losses in each of the switching stages. Improvements in the converter efficiency can be achieved by dynamically changing the number of active phases depending on the load current...

  4. Using Landsat-derived disturbance history (1972-2010) to predict current forest structure

    Science.gov (United States)

    Dirk Pflugmacher; Warren B. Cohen; Robert E. Kennedy

    2012-01-01

    Lidar is currently the most accurate method for remote estimation of forest structure, but it has limited spatial and temporal coverage. Conversely, Landsat data are more widely available, but exhibit a weaker relationship with structure under medium to high leaf area conditions. One potentially valuable means of enhancing the relationship between Landsat reflectance...

  5. A Review of Additive Mixed-Electric Discharge Machining: Current Status and Future Perspectives for Surface Modification of Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Abdul’Azeez Abdu Aliyu

    2017-01-01

    Full Text Available Surface treatment remained a key solution to numerous problems of synthetic hard tissues. The basic methods of implant surface modification include various physical and chemical deposition techniques. However, most of these techniques have several drawbacks such as excessive cost and surface cracks and require very high sintering temperature. Additive mixed-electric discharge machining (AM-EDM is an emerging technology which simultaneously acts as a machining and surface modification technique. Aside from the mere molds, dies, and tool fabrication, AM-EDM is materializing to finishing of automobiles and aerospace, nuclear, and biomedical components, through the concept of material migrations. The mechanism of material transfer by AM-EDM resembles electrophoretic deposition, whereby the additives in the AM-EDM dielectric fluids are melted and migrate to the machined surface, forming a mirror-like finishing characterized by extremely hard, nanostructured, and nanoporous layers. These layers promote the bone in-growth and strengthen the cell adhesion. Implant shaping and surface treatment through AM-EDM are becoming a key research focus in recent years. This paper reports and summarizes the current advancement of AM-EDM as a potential tool for orthopedic and dental implant fabrication. Towards the end of this paper, the current challenges and future research trends are highlighted.

  6. Comparisons Between Model Predictions and Spectral Measurements of Charged and Neutral Particles on the Martian Surface

    Science.gov (United States)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F.; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; hide

    2014-01-01

    Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Radiation Assessment Detector (RAD) on the Curiosity rover since August 2012. RAD is a particle detector that measures the energy spectrum of charged particles (10 to approx. 200 MeV/u) and high energy neutrons (approx 8 to 200 MeV). The data obtained on the surface of Mars for 300 sols are compared to the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant angles, and the model accounts for shielding of the RAD "E" dosimetry detector by the rest of the instrument. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and suggest that future radiation environments on Mars can be predicted accurately. These contributions lend support to the understanding of radiation health risks to astronauts for the planning of various mission scenarios

  7. Permeability surface area product analysis in malignant brain edema prediction - A pilot study.

    Science.gov (United States)

    Volny, O; Cimflova, P; Lee, T-Y; Menon, B K; d'Esterre, C D

    2017-05-15

    Using an extended CT perfusion acquisition (150s), we sought to determine the association between perfusion parameters and malignant edema after ischemic stroke. Patients (from prospective study PROVE-IT, NCT02184936) with terminal internal carotid artery±proximal middle cerebral occlusion were involved. CTA was assessed for clot location and status of leptomeningeal collaterals. The following CTP parameters were calculated within the ischemic territory and contralaterally: permeability surface area product (PS), cerebral blood flow (CBF) and cerebral blood volume (CBV). PS was calculated using the adiabatic approximation to the Johnson and Wilson model. Outcome was evaluated by midline shift and infarction volume on follow-up imaging. Of 200 patients enrolled, 7 patients (3.5%) had midline shift≥5mm (2 excluded for poor-quality scans). Five patients with midline shift and 5 matched controls were analysed. There was no significant difference in mean PS, CBF and CBV within the ischemic territory between the two groups. A CBV threshold of 1.7ml/100g had the highest AUC=0.72, 95% CI=0.54-0.90 for early midline shift prediction, sensitivity and specificity were 0.83 and 0.67 respectively. Our preliminary results did not show significant differences in permeability surface area analysis if analysed for complete ischemic region. CBV parameter had the highest accuracy and there was a trend for the mean PS values for midline shift prediction. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Prediction of Outside Surface Aluminium Tank Corrosion on TRIGA Mark - IIResearch Reactor Bandung

    International Nuclear Information System (INIS)

    Soedardjo

    2000-01-01

    The prediction of outside surface aluminium tank corrosion on researchreactor design which coated by epoxy paint, has been assessed. The new TRIGAMark - II Bandung research reactor tank design separated by 3 section arebottom, middle and upper section then inserted into the existing old reactor.The separation carried out caused by the space constraint on top of old tank,so that the novel tank impossible inserted into old tank all at once. Thespace between novel and old tank is 10 mm. After bottom and middle section oftank welded then followed by epoxy painting and inserted partially into oldtank. From then on the middle and upper section welded and followed by epoxypainting then inserted into old tank. Based on prediction result, that theroot cause of corrosion would be took place on welding and on imperfectlyepoxy painting area. The outside surface novel tank would be generated by thereaction between imperfectly epoxy painting area and the highly basecondition on cement grout that available on novel and old tank gap. (author)

  9. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    Science.gov (United States)

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  10. Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

    Science.gov (United States)

    Isern-Fontanet, Jordi; Ballabrera-Poy, Joaquim; Turiel, Antonio; García-Ladona, Emilio

    2017-10-01

    Ocean currents play a key role in Earth's climate - they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

  11. Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

    Directory of Open Access Journals (Sweden)

    J. Isern-Fontanet

    2017-10-01

    Full Text Available Ocean currents play a key role in Earth's climate – they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

  12. Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions

    Science.gov (United States)

    Hengl, Tomislav; Heuvelink, Gerard B. M.; Kempen, Bas; Leenaars, Johan G. B.; Walsh, Markus G.; Shepherd, Keith D.; Sila, Andrew; MacMillan, Robert A.; Mendes de Jesus, Jorge; Tamene, Lulseged; Tondoh, Jérôme E.

    2015-01-01

    80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008–2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management—organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15–75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological

  13. Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions.

    Science.gov (United States)

    Hengl, Tomislav; Heuvelink, Gerard B M; Kempen, Bas; Leenaars, Johan G B; Walsh, Markus G; Shepherd, Keith D; Sila, Andrew; MacMillan, Robert A; Mendes de Jesus, Jorge; Tamene, Lulseged; Tondoh, Jérôme E

    2015-01-01

    80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008-2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management--organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15-75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological

  14. Study on characteristics of eddy current array coil operated in transmit-receive mode and surface inspection using this probe

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Hun; Jee, Dong Hyun; Cho, Chan Hee; Kim, In Chul [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    Eddy current array (ECA) technology provides the ability to electronically scan without mechanical scanning for a footprint of probe that consists of several eddy current coils arranged side-by-side and two dimensionally. Compared to single-coil eddy current technology, the ECA technology has a higher inspection speed and reliability because a large area can be covered in a single-probe pass and the obtained images can facilitate data interpretation. In this study, we developed an eddy current array probe with 2×16 coil arrays and a multiplexer that can select transmit-receive coils sequentially and operate in transmit-receive mode. Surface inspection was performed using this probe for specimens that had various flaws and the characteristics of transmit-receive mode ECA technology was studied through an analysis of the obtained eddy current signals and C-scan images.

  15. Experimental study on magnetically insulated transmission line electrode surface evolution process under MA/cm current density

    International Nuclear Information System (INIS)

    Zhang, PengFei; Qiu, Aici; Hu, Yang; Yang, HaiLiang; Sun, Jiang; Wang, Liangping; Cong, Peitian

    2016-01-01

    The design of high-current density magnetically insulated transmission line (MITL) is a difficult problem of current large-scale Z-pinch device. In particular, a thorough understanding of the MITL electrode surface evolution process under high current density is lacking. On the “QiangGuang-I” accelerator, the load area possesses a low inductance short-circuit structure with a diameter of 2.85 mm at the cathode, and three reflux columns with a diameter of 3 mm and uniformly distributed circumference at the anode. The length of the high density MITL area is 20 mm. A laser interferometer is used to assess and analyze the state of the MITL cathode and anode gap, and their evolution process under high current density. Experimental results indicate that evident current loss is not observed in the current density area at pulse leading edge, and peak when the surface current density reaches MA/cm. Analysis on electrode surface working conditions indicates that when the current leading edge is at 71.5% of the peak, the total evaporation of MITL cathode structure can be realized by energy deposition caused by ohmic heating. The electrode state changes, and diffusion conditions are reflected in the laser interferometer image. The MITL cathode area mainly exists in metal vapor form. The metal vapor density in the cathode central region is higher than the upper limit of laser penetration density (∼4 × 10 21 /cm 3 ), with an expansion velocity of ∼0.96 km/s. The metal vapor density in the electrode outer area may lead to evident distortion of fringes, and its expansion velocity is faster than that in the center area (1.53 km/s).

  16. Finite element model predicts current density distribution for clinical applications of tDCS and tACS

    Directory of Open Access Journals (Sweden)

    Toralf eNeuling

    2012-09-01

    Full Text Available Transcranial direct current stimulation (tDCS has been applied in numerous scientific studies over the past decade. However, the possibility to apply tDCS in therapy of neuropsychiatric disorders is still debated. While transcranial magnetic stimulation (TMS has been approved for treatment of major depression in the United States by the Food and Drug Administration (FDA, tDCS is not as widely accepted. One of the criticisms against tDCS is the lack of spatial specificity. Focality is limited by the electrode size (35 cm2 are commonly used and the bipolar arrangement. However, a current flow through the head directly from anode to cathode is an outdated view. Finite element (FE models have recently been used to predict the exact current flow during tDCS. These simulations have demonstrated that the current flow depends on tissue shape and conductivity. Toface the challenge to predict the location, magnitude and direction of the current flow induced by tDCS and transcranial alternating current stimulation (tACS, we used a refined realistic FE modeling approach. With respect to the literature on clinical tDCS and tACS, we analyzed two common setups for the location of the stimulation electrodes which target the frontal lobe and the occipital lobe, respectively. We compared lateral and medial electrode configuration with regard to theirusability. We were able to demonstrate that the lateral configurations yielded more focused stimulation areas as well as higher current intensities in the target areas. The high resolution of our simulation allows one to combine the modeled current flow with the knowledge of neuronal orientation to predict the consequences of tDCS and tACS. Our results not only offer a basis for a deeper understanding of the stimulation sites currently in use for clinical applications but also offer a better interpretation of observed effects.

  17. A study of surface diffusion with the scanning tunneling microscope from fluctuations of the tunneling current

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, Lozano [Iowa State Univ., Ames, IA (United States)

    1996-01-12

    The transport of atoms or molecules over surfaces has been an important area of study for several decades now, with its progress generally limited by the available experimental techniques to characterize the phenomena. A number of methods have been developed over the years to measure surface diffusion yet only very few systems have been characterized to this day mainly due to the physical limitations inherent in these available methods. Even the STM with its astonishing atomically-resolved images of the surface has been limited in terms of its capability to determine mass transport properties. This is because the STM is inherently a ``slow`` instrument, i.e., a finite time is needed for signal averaging in order to produce the image. A need exists for additional surface diffusion measurement techniques, ideally ones which are able to study varied systems and measure a wide range of diffusion rates. The STM (especially because of its highly local nature) presents itself as a promising tool to conduct dynamical studies if its poor time resolution during ``normal operation`` can somehow be overcome. The purpose of this dissertation is to introduce a new technique of using the STM to measure adatom mobility on surfaces -- one with a capacity to achieve excellent time resolution.

  18. An Algorithm for Surface Current Retrieval from X-band Marine Radar Images

    Directory of Open Access Journals (Sweden)

    Chengxi Shen

    2015-06-01

    Full Text Available In this paper, a novel current inversion algorithm from X-band marine radar images is proposed. The routine, for which deep water is assumed, begins with 3-D FFT of the radar image sequence, followed by the extraction of the dispersion shell from the 3-D image spectrum. Next, the dispersion shell is converted to a polar current shell (PCS using a polar coordinate transformation. After removing outliers along each radial direction of the PCS, a robust sinusoidal curve fitting is applied to the data points along each circumferential direction of the PCS. The angle corresponding to the maximum of the estimated sinusoid function is determined to be the current direction, and the amplitude of this sinusoidal function is the current speed. For validation, the algorithm is tested against both simulated radar images and field data collected by a vertically-polarized X-band system and ground-truthed with measurements from an acoustic Doppler current profiler (ADCP. From the field data, it is observed that when the current speed is less than 0.5 m/s, the root mean square differences between the radar-derived and the ADCP-measured current speed and direction are 7.3 cm/s and 32.7°, respectively. The results indicate that the proposed procedure, unlike most existing current inversion schemes, is not susceptible to high current speeds and circumvents the need to consider aliasing. Meanwhile, the relatively low computational cost makes it an excellent choice in practical marine applications.

  19. Using Google Earth Surface Metrics to Predict Plant Species Richness in a Complex Landscape

    Directory of Open Access Journals (Sweden)

    Sebastián Block

    2016-10-01

    Full Text Available Google Earth provides a freely available, global mosaic of high-resolution imagery from different sensors that has become popular in environmental and ecological studies. However, such imagery lacks the near-infrared band often used in studying vegetation, thus its potential for estimating vegetation properties remains unclear. In this study, we assess the potential of Google Earth imagery to describe and predict vegetation attributes. Further, we compare it to the potential of SPOT imagery, which has additional spectral information. We measured basal area, vegetation height, crown cover, density of individuals, and species richness in 60 plots in the oak forests of a complex volcanic landscape in central Mexico. We modelled each vegetation attribute as a function of surface metrics derived from Google Earth and SPOT images, and selected the best-supported linear models from each source. Total species richness was the best-described and predicted variable: the best Google Earth-based model explained nearly as much variation in species richness as its SPOT counterpart (R2 = 0.44 and 0.51, respectively. However, Google Earth metrics emerged as poor predictors of all remaining vegetation attributes, whilst SPOT metrics showed potential for predicting vegetation height. We conclude that Google Earth imagery can be used to estimate species richness in complex landscapes. As it is freely available, Google Earth can broaden the use of remote sensing by researchers and managers in low-income tropical countries where most biodiversity hotspots are found.

  20. Current immunological and molecular tools for leptospirosis: diagnostics, vaccine design, and biomarkers for predicting severity.

    Science.gov (United States)

    Rajapakse, Senaka; Rodrigo, Chaturaka; Handunnetti, Shiroma M; Fernando, Sumadhya Deepika

    2015-01-16

    Leptospirosis is a zoonotic spirochaetal illness that is endemic in many tropical countries. The research base on leptospirosis is not as strong as other tropical infections such as malaria. However, it is a lethal infection that can attack many vital organs in its severe form, leading to multi-organ dysfunction syndrome and death. There are many gaps in knowledge regarding the pathophysiology of leptospirosis and the role of host immunity in causing symptoms. This hinders essential steps in combating disease, such as developing a potential vaccine. Another major problem with leptospirosis is the lack of an easy to perform, accurate diagnostic tests. Many clinicians in resource limited settings resort to clinical judgment in diagnosing leptospirosis. This is unfortunate, as many other diseases such as dengue, hanta virus, rickettsial infections, and even severe bacterial sepsis, can mimic leptospirosis. Another interesting problem is the prediction of disease severity at the onset of the illness. The majority of patients recover from leptospirosis with only a mild febrile illness, while a few others have severe illness with multi-organ failure. Clinical features are poor predictors of potential severity of infection, and therefore the search is on for potential biomarkers that can serve as early warnings for severe disease. This review concentrates on these three important aspects of this neglected tropical disease: diagnostics, developing a vaccine, and potential biomarkers to predict disease severity.

  1. Current Controversies in the Prediction, Diagnosis, and Management of Cerebral Vasospasm: Where Do We Stand?

    Directory of Open Access Journals (Sweden)

    Young Lee

    2013-01-01

    Full Text Available Aneurysmal subarachnoid hemorrhage occurs in approximately 30,000 persons in the United States each year. Around 30 percent of patients with aneurysmal subarachnoid hemorrhage suffer from cerebral ischemia and infarction due to cerebral vasospasm, a leading cause of treatable death and disability following aneurysmal subarachnoid hemorrhage. Methods used to predict, diagnose, and manage vasospasm are the topic of recent active research. This paper utilizes a comprehensive review of the recent literature to address controversies surrounding these topics. Evidence regarding the effect of age, smoking, and cocaine use on the incidence and outcome of vasospasm is reviewed. The abilities of different computed tomography grading schemes to predict vasospasm in the aftermath of subarachnoid hemorrhage are presented. Additionally, the utility of different diagnostic methods for the detection and visualization of vasospasm, including transcranial Doppler ultrasonography, CT angiography, digital subtraction angiography, and CT perfusion imaging is discussed. Finally, the recent literature regarding interventions for the prophylaxis and treatment of vasospasm, including hyperdynamic therapy, albumin, calcium channel agonists, statins, magnesium sulfate, and endothelin antagonists is summarized. Recent studies regarding each topic were reviewed for consensus recommendations from the literature, which were then presented.

  2. A Review of Current Machine Learning Methods Used for Cancer Recurrence Modeling and Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Hemphill, Geralyn M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-27

    Cancer has been characterized as a heterogeneous disease consisting of many different subtypes. The early diagnosis and prognosis of a cancer type has become a necessity in cancer research. A major challenge in cancer management is the classification of patients into appropriate risk groups for better treatment and follow-up. Such risk assessment is critically important in order to optimize the patient’s health and the use of medical resources, as well as to avoid cancer recurrence. This paper focuses on the application of machine learning methods for predicting the likelihood of a recurrence of cancer. It is not meant to be an extensive review of the literature on the subject of machine learning techniques for cancer recurrence modeling. Other recent papers have performed such a review, and I will rely heavily on the results and outcomes from these papers. The electronic databases that were used for this review include PubMed, Google, and Google Scholar. Query terms used include “cancer recurrence modeling”, “cancer recurrence and machine learning”, “cancer recurrence modeling and machine learning”, and “machine learning for cancer recurrence and prediction”. The most recent and most applicable papers to the topic of this review have been included in the references. It also includes a list of modeling and classification methods to predict cancer recurrence.

  3. Are the current chronic allograft nephropathy grading systems sufficient to predict renal allograft survival?

    Directory of Open Access Journals (Sweden)

    G.T. Moscoso-Solorzano

    2008-10-01

    Full Text Available A major problem in renal transplantation is identifying a grading system that can predict long-term graft survival. The present study determined the extent to which the two existing grading systems (Banff 97 and chronic allograft damage index, CADI correlate with each other and with graft loss. A total of 161 transplant patient biopsies with chronic allograft nephropathy (CAN were studied. The samples were coded and evaluated blindly by two pathologists using the two grading systems. Logistic regression analyses were used to evaluate the best predictor index for renal allograft loss. Patients with higher Banff 97 and CADI scores had higher rates of graft loss. Moreover, these measures also correlated with worse renal function and higher proteinuria levels at the time of CAN diagnosis. Logistic regression analyses showed that the use of angiotensin-converting enzyme inhibitor (ACEI, hepatitis C virus (HCV, tubular atrophy, and the use of mycophenolate mofetil (MMF were associated with graft loss in the CADI, while the use of ACEI, HCV, moderate interstitial fibrosis and tubular atrophy and the use of MMF were associated in the Banff 97 index. Although Banff 97 and CADI analyze different parameters in different renal compartments, only some isolated parameters correlated with graft loss. This suggests that we need to review the CAN grading systems in order to devise a system that includes all parameters able to predict long-term graft survival, including chronic glomerulopathy, glomerular sclerosis, vascular changes, and severity of chronic interstitial fibrosis and tubular atrophy.

  4. Are the current chronic allograft nephropathy grading systems sufficient to predict renal allograft survival?

    Directory of Open Access Journals (Sweden)

    G.T. Moscoso-Solorzano

    Full Text Available A major problem in renal transplantation is identifying a grading system that can predict long-term graft survival. The present study determined the extent to which the two existing grading systems (Banff 97 and chronic allograft damage index, CADI correlate with each other and with graft loss. A total of 161 transplant patient biopsies with chronic allograft nephropathy (CAN were studied. The samples were coded and evaluated blindly by two pathologists using the two grading systems. Logistic regression analyses were used to evaluate the best predictor index for renal allograft loss. Patients with higher Banff 97 and CADI scores had higher rates of graft loss. Moreover, these measures also correlated with worse renal function and higher proteinuria levels at the time of CAN diagnosis. Logistic regression analyses showed that the use of angiotensin-converting enzyme inhibitor (ACEI, hepatitis C virus (HCV, tubular atrophy, and the use of mycophenolate mofetil (MMF were associated with graft loss in the CADI, while the use of ACEI, HCV, moderate interstitial fibrosis and tubular atrophy and the use of MMF were associated in the Banff 97 index. Although Banff 97 and CADI analyze different parameters in different renal compartments, only some isolated parameters correlated with graft loss. This suggests that we need to review the CAN grading systems in order to devise a system that includes all parameters able to predict long-term graft survival, including chronic glomerulopathy, glomerular sclerosis, vascular changes, and severity of chronic interstitial fibrosis and tubular atrophy.

  5. Plasma Formation and Evolution on Cu, Al, Ti, and Ni Surfaces Driven by a Mega-Ampere Current Pulse

    Science.gov (United States)

    Yates, Kevin C.

    Metal alloy mm-diameter rods have been driven by a 1-MA, 100-ns current pulse from the Zebra z-pinch. The intense current produces megagauss surface magnetic fields that diffuse into the load, ohmically heating the metal until plasma forms. Because the radius is much thicker than the skin depth, the magnetic field reaches a much higher value than around a thin-wire load. With the "barbell" load design, plasma formation in the region of interest due to contact arcing or electron avalanche is avoided, allowing for the study of ohmically heated loads. Work presented here will show first evidence of a magnetic field threshold for plasma formation in copper 101, copper 145, titanium, and nickel, and compare with previous work done with aluminum. Copper alloys 101 and 145, titanium grade II, and nickel alloy 200 form plasma when the surface magnetic field reaches 3.5, 3.0, 2.2, and 2.6 megagauss, respectively. Varying the element metal, as well as the alloy, changes multiple physical properties of the load and affects the evolution of the surface material through the multiple phase changes. Similarities and differences between these metals will be presented, giving motivation for continued work with different material loads. During the current rise, the metal is heated to temperatures that cause multiple phase changes. When the surface magnetic field reaches a threshold, the metal ionizes and the plasma becomes pinched against the underlying cooler, dense material. Diagnostics fielded have included visible light radiometry, two-frame shadowgraphy (266 and 532 nm wavelengths), time-gated EUV spectroscopy, single-frame/2ns gated imaging, and multi-frame/4ns gated imaging with an intensified CCD camera (ICCD). Surface temperature, expansion speeds, instability growth, time of plasma formation, and plasma uniformity are determined from the data. The time-period of potential plasma formation is scrutinized to understand if and when plasma forms on the surface of a heated

  6. Predicting Trophic Interactions and Habitat Utilization in the California Current Ecosystem

    Science.gov (United States)

    2015-09-30

    ecosystem models may be implemented (e.g., Southern Ocean ). A main advantage in using model output to diagnose the occurrence and persistence of...may impact suitable habitat distributions in the CCLME or other regions of the world oceans . REFERENCES Peterson, W. T., & Schwing, F. B. (2003...in the California Current Ecosystem Jerome Fiechter UC Santa Cruz Institute of Marine Sciences 1156 High Street Santa Cruz, CA 95064 phone

  7. Low-temperature gaseous surface hardening of stainless steel: the current status

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2009-01-01

    The present review addresses the state of the art of low-temperature gaseous surface engineering of (austenitic) stainless steel and is largely based on the authors' own work in the last 10 years. The main purpose of low temperature gaseous surface engineering of stainless steel is to develop...... a hardened case at the surface, while maintaining the superior corrosion performance. This can be achieved by dissolving colossal amounts of nitrogen and/or carbon without forming nitrides and/or carbides, thus developing so-called expanded austenite. The present work gives an overview over results obtained...... on homogeneous expanded austenite and covers the crystallography for nitrogen- and carbon-stabilised expanded austenite, the solubility for nitrogen and carbon, the diffusion of these interstitials as well as the stability of expanded austenite with respect to nitride and carbide formation. Subsequently...

  8. Uncertainty in solid precipitation and snow depth prediction for Siberia using the Noah and Noah-MP land surface models

    Science.gov (United States)

    Suzuki, Kazuyoshi; Zupanski, Milija

    2018-01-01

    In this study, we investigate the uncertainties associated with land surface processes in an ensemble predication context. Specifically, we compare the uncertainties produced by a coupled atmosphere-land modeling system with two different land surface models, the Noah- MP land surface model (LSM) and the Noah LSM, by using the Maximum Likelihood Ensemble Filter (MLEF) data assimilation system as a platform for ensemble prediction. We carried out 24-hour prediction simulations in Siberia with 32 ensemble members beginning at 00:00 UTC on 5 March 2013. We then compared the model prediction uncertainty of snow depth and solid precipitation with observation-based research products and evaluated the standard deviation of the ensemble spread. The prediction skill and ensemble spread exhibited high positive correlation for both LSMs, indicating a realistic uncertainty estimation. The inclusion of a multiple snowlayer model in the Noah-MP LSM was beneficial for reducing the uncertainties of snow depth and snow depth change compared to the Noah LSM, but the uncertainty in daily solid precipitation showed minimal difference between the two LSMs. The impact of LSM choice in reducing temperature uncertainty was limited to surface layers of the atmosphere. In summary, we found that the more sophisticated Noah-MP LSM reduces uncertainties associated with land surface processes compared to the Noah LSM. Thus, using prediction models with improved skill implies improved predictability and greater certainty of prediction.

  9. Current challenges in glioblastoma: intratumour heterogeneity, residual disease and models to predict disease recurrence

    Directory of Open Access Journals (Sweden)

    Hayley Patricia Ellis

    2015-11-01

    Full Text Available Glioblastoma (GB is the most common malignant primary brain tumour, and despite the availability of chemotherapy and radiotherapy to combat the disease, overall survival remains low with a high incidence of tumour recurrence. Technological advances are continually improving our understanding of the disease and in particular our knowledge of clonal evolution, intratumour heterogeneity and possible reservoirs of residual disease. These may inform how we approach clinical treatment and recurrence in GB. Mathematical modelling (including neural networks, and strategies such as multiple-sampling during tumour resection and genetic analysis of circulating cancer cells, may be of great future benefit to help predict the nature of residual disease and resistance to standard and molecular therapies in GB.

  10. Serum uric acid predicts both current and future components of the metabolic syndrome.

    Science.gov (United States)

    Osgood, Kristy; Krakoff, Jonathan; Thearle, Marie

    2013-06-01

    Uric acid (UA) is known to be associated with excess adiposity and insulin resistance. Our aim was to investigate the relationship between UA and the factors associated with the metabolic syndrome and type 2 diabetes mellitus (T2DM), both initially and longitudinally. Serum UA was assessed as a potential determinant of concurrent blood pressure, serum lipids, glucose regulation measured via an oral glucose tolerance test (OGTT), acute insulin response (AIR), and insulin action (M) measured with hyperinsulinemic-euglycemic clamps in 245 participants (72% Native American, 56% male). UA was also assessed as a predictor of the above variables in 60 participants with follow-up data available (median follow-up time=11.2 years [interquartile range (IQR)=8.1, 13.6 years]. The impact of UA on the risk of T2DM was determined as 36 of the 245 participants developed T2DM after the baseline visit. UA was negatively associated with both concurrent and future M, such that for every 1 mg/dL increase in serum UA, M decreased 7.6% (P<0.001) and future M decreased 6.3% (P=0.02). However, UA was not associated with AIR (P=0.7). UA concentrations were a predictor of T2DM [hazard risk ratio (HRR)=1.5; P=0.02]. UA was positively associated with both concurrent blood pressure and lipids and also predicted future increases in blood pressure and total cholesterol. Not only did UA associate with concomitant insulin action, blood pressure, and lipids, it also predicted future declines in insulin action and T2DM. UA is a potential target for preventing decreases in insulin sensitivity and rises in blood pressure and cholesterol.

  11. Sex-related differences in predicting choledocholithiasis using current American Society of Gastrointestinal Endoscopy risk criteria

    Science.gov (United States)

    Chhoda, Ankit; Jain, Deepanshu; Singhal, Shashideep

    2017-01-01

    Background: American Society of Gastrointestinal Endoscopy (ASGE) criteria is widely used to predict probability of choledocholithiasis among patients with symptomatic gallstone disease but does not take sex into consideration. Methods: The cohort study included patients who underwent either endoscopic retrograde cholangiopancreatography or intraoperative cholangiography for suspected choledocholithiasis at our medical center. Clinical, laboratory and radiological data were collected for each patient and used to stratify them based on the ASGE risk criteria for choledocholithiasis. Results: A total of 646 patients composed the final study cohort. The composite incidence rate of choledocholithiasis for male and female groups was 47.5% and 46.2% respectively. Total bilirubin (>4 mg/dL), cholangitis, abnormal liver function tests (transaminitis), dilation of the common bile duct (>6 mm) on ultrasound examination, and biliary pancreatitis were individually associated with choledocholithiasis in 73.5%, 68.4%, 61.1%, 60.0%, and 51.7% of males, respectively. Total bilirubin >4 mg/dL and 1.8-4 mg/dL, cholangitis, and transaminitis were individually associated with choledocholithiasis in 82.6%, 64.0%, 58.2%, and 50.0% of females, respectively. The distribution in probability group/incidence of choledocholithiasis was as follows: for males, low probability 3.3%/0%, intermediate probability 56.7%/33.8%), high probability 40%/77.8%; and for females, low probability 5.3%/14.3%, intermediate probability 70.2%/39.6%, high probability 24.5%/72.1%. Conclusions: The composite incidence for choledocholithiasis was similar across male and female patients. A significantly higher proportion of females compared to males were in the intermediate probability group. Better sex stratification can help improve the positive and negative predictive values of ASGE risk stratification criteria. Improve patient outcomes and reduce associated healthcare cost. PMID:29118564

  12. Assessing allometric models to predict vegetative growth of mango (Mangifera indica; Anacardiaceae) at the current-year branch scale.

    Science.gov (United States)

    Normand, Frédéric; Lauri, Pierre-Éric

    2012-03-01

    Accurate and reliable predictive models are necessary to estimate nondestructively key variables for plant growth studies such as leaf area and leaf, stem, and total biomass. Predictive models are lacking at the current-year branch scale despite the importance of this scale in plant science. We calibrated allometric models to estimate leaf area and stem and branch (leaves + stem) mass of current-year branches, i.e., branches several months old studied at the end of the vegetative growth season, of four mango cultivars on the basis of their basal cross-sectional area. The effects of year, site, and cultivar were tested. Models were validated with independent data and prediction accuracy was evaluated with the appropriate statistics. Models revealed a positive allometry between dependent and independent variables, whose y-intercept but not the slope, was affected by the cultivar. The effects of year and site were negligible. For each branch characteristic, cultivar-specific models were more accurate than common models built with pooled data from the four cultivars. Prediction quality was satisfactory but with data dispersion around the models, particularly for large values. Leaf area and stem and branch mass of mango current-year branches could be satisfactorily estimated on the basis of branch basal cross-sectional area with cultivar-specific allometric models. The results suggested that, in addition to the heteroscedastic behavior of the variables studied, model accuracy was probably related to the functional plasticity of branches in relation to the light environment and/or to the number of growth units composing the branches.

  13. Stable water isotope simulation by current land-surface schemes:Results of IPILPS phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Henderson-Sellers, A.; Fischer, M.; Aleinov, I.; McGuffie, K.; Riley, W.J.; Schmidt, G.A.; Sturm, K.; Yoshimura, K.; Irannejad, P.

    2005-10-31

    Phase 1 of isotopes in the Project for Intercomparison of Land-surface Parameterization Schemes (iPILPS) compares the simulation of two stable water isotopologues ({sup 1}H{sub 2} {sup 18}O and {sup 1}H{sup 2}H{sup 16}O) at the land-atmosphere interface. The simulations are off-line, with forcing from an isotopically enabled regional model for three locations selected to offer contrasting climates and ecotypes: an evergreen tropical forest, a sclerophyll eucalypt forest and a mixed deciduous wood. Here we report on the experimental framework, the quality control undertaken on the simulation results and the method of intercomparisons employed. The small number of available isotopically-enabled land-surface schemes (ILSSs) limits the drawing of strong conclusions but, despite this, there is shown to be benefit in undertaking this type of isotopic intercomparison. Although validation of isotopic simulations at the land surface must await more, and much more complete, observational campaigns, we find that the empirically-based Craig-Gordon parameterization (of isotopic fractionation during evaporation) gives adequately realistic isotopic simulations when incorporated in a wide range of land-surface codes. By introducing two new tools for understanding isotopic variability from the land surface, the Isotope Transfer Function and the iPILPS plot, we show that different hydrological parameterizations cause very different isotopic responses. We show that ILSS-simulated isotopic equilibrium is independent of the total water and energy budget (with respect to both equilibration time and state), but interestingly the partitioning of available energy and water is a function of the models' complexity.

  14. Predicting the effects of measures to reduce eutrophication in surface water in rural areas - a case study

    NARCIS (Netherlands)

    Hendriks, R.F.A.; Kolk, van der J.W.H.

    1995-01-01

    The effectiveness of measures to reduce nutrient concentrations in surface water was predicted by a combination of a nutrient leaching model for groundwater and a nutrient simulation model for surface water. Scenarios were formulated based on several measures. Different combinations of drainage

  15. How accurately do current force fields predict experimental peptide conformations? An adiabatic free energy dynamics study.

    Science.gov (United States)

    Tzanov, Alexandar T; Cuendet, Michel A; Tuckerman, Mark E

    2014-06-19

    The quality of classical biomolecular simulations is inevitably limited by two problems: the accuracy of the force field used and the comprehensiveness of configuration space sampling. In this work we tackle the sampling problem by carrying out driven adiabatic free energy dynamics to obtain converged free energy surfaces of dipeptides in the gas phase and in solution using selected dihedral angles as collective variables. To calculate populations of conformational macrostates observed in experiment, we introduce a fuzzy clustering algorithm in collective-variable space, which delineates macrostates without prior definition of arbitrary boundaries. With this approach, we calculate the conformational preferences of small peptides with six biomolecular force fields chosen from among the most recent and widely used. We assess the accuracy of each force field against recently published Raman or IR-UV spectroscopy measurements of conformer populations for the dipeptides in solution or in the gas phase.

  16. Surface quality prediction model of nano-composite ceramics in ultrasonic vibration-assisted ELID mirror grinding

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Bo; Chen, Fan; Jia, Xiao-feng; Zhao, Chong-yang; Wang, Xiao-bo [Henan Polytechnic University, Jiaozuo (China)

    2017-04-15

    Ultrasonic vibration-assisted Electrolytic in-process dressing (ELID) grinding is a highly efficient and highly precise machining method. The surface quality prediction model in ultrasonic vibration-assisted ELID mirror grinding was studied. First, the interaction between grits and workpiece surface was analyzed according to kinematic mechanics, and the surface roughness model was developed. The variations in surface roughness under different parameters was subsequently calculated and analyzed by MATLAB. Results indicate that compared with the ordinary ELID grinding, ultrasonic vibration-assisted ELID grinding is superior, because it has more stable and better surface quality and has an improved range of ductile machining.

  17. Investigating the role of wind in generating surface currents over the slope area of the Laptev Sea, Arctic Ocean

    Science.gov (United States)

    Patteson, R. N.

    2017-12-01

    Mixing mechanisms of the Arctic Ocean have profound impacts on sea ice, global ocean dynamics, and arctic communities. This project used a two-year long time series of ocean current velocities collected from eight moorings located on the Eurasian basin, as well as ERA-interim wind data, to compare and assess relationships between current and wind velocities at different depths. Determining the strength of these correlations will further scientific understanding of the degree to which wind influences mixing, with implications for heat flux, diffusion, and sea ice changes. Using statistical analysis, I calculated whether a significant relationship between wind velocity and ocean currents existed beginning at the surface level ( 50m) .The final correlation values, ranging from R = 0.11 to R = 0.28, indicated a weak relationship between wind velocity and ocean currents at the surface for all eight mooring sites. The results for the surface depth imply that correlation likely decreases with increasing depths, and thus further testing of deeper depth levels was unnecessary. This finding suggests that there is another dominant factor at play in the ocean; we postulate that topography exerts a significant influence on subsurface mixing. This study highlights the need for further research of the different mechanisms and their importance in influencing the dynamic structure of the ocean.

  18. Prediction of Ablation Rates from Solid Surfaces Exposed to High Temperature Gas Flow

    Science.gov (United States)

    Akyuzlu, Kazim M.; Coote, David

    2013-01-01

    ablation. Two different ablation models are proposed to determine the heat loss from the solid surface due to the ablation of the solid material. Both of them are physics based. Various numerical simulations were carried out using both models to predict the temperature distribution in the solid and in the gas flow, and then predict the ablation rates at a typical NTR motor hydrogen gas temperature and pressure. Solid mass loss rate per foot of a pipe was also calculated from these predictions. The results are presented for fully developed turbulent flow conditions in a sample SS pipe with a 6 inch diameter.

  19. Experimental study of neoclassical currents

    International Nuclear Information System (INIS)

    Zarnstorff, M.C.; Prager, S.C.

    1985-05-01

    A detailed experimental study is presented of the bootstrap and Pfirsch-Schlueter currents that are predicted by neoclassical transport theory. In a toroidal octupole, on magnetic surfaces within the separatrix, the observed parallel plasma currents are in excellent quantitative agreement with neoclassical theory with regard to the spatial structure (along a magnetic surface), collisionality dependence and toroidal magnetic field dependence. On magnetic surfaces outside the separatrix, the ion portion of the parallel current is in agreement with neoclassical theory but the electron parallel current is observed to obtain a unidirectional component which deviates from and exceeds the theoretical prediction

  20. Using dose-surface maps to predict radiation-induced rectal bleeding: a neural network approach

    Science.gov (United States)

    Buettner, Florian; Gulliford, Sarah L.; Webb, Steve; Partridge, Mike

    2009-09-01

    The incidence of late-toxicities after radiotherapy can be modelled based on the dose delivered to the organ under consideration. Most predictive models reduce the dose distribution to a set of dose-volume parameters and do not take the spatial distribution of the dose into account. The aim of this study was to develop a classifier predicting radiation-induced rectal bleeding using all available information on the dose to the rectal wall. The dose was projected on a two-dimensional dose-surface map (DSM) by virtual rectum-unfolding. These DSMs were used as inputs for a classification method based on locally connected neural networks. In contrast to fully connected conventional neural nets, locally connected nets take the topology of the input into account. In order to train the nets, data from 329 patients from the RT01 trial (ISRCTN 47772397) were split into ten roughly equal parts. By using nine of these parts as a training set and the remaining part as an independent test set, a ten-fold cross-validation was performed. Ensemble learning was used and 250 nets were built from randomly selected patients from the training set. Out of these 250 nets, an ensemble of expert nets was chosen. The performances of the full ensemble and of the expert ensemble were quantified by using receiver-operator-characteristic (ROC) curves. In order to quantify the predictive power of the shape, ensembles of fully connected conventional neural nets based on dose-surface histograms (DSHs) were generated and their performances were quantified. The expert ensembles performed better than or equally as well as the full ensembles. The area under the ROC curve for the DSM-based expert ensemble was 0.64. The area under the ROC curve for the DSH-based expert ensemble equalled 0.59. This difference in performance indicates that not only volumetric, but also morphological aspects of the dose distribution are correlated to rectal bleeding after radiotherapy. Thus, the shape of the dose

  1. Using dose-surface maps to predict radiation-induced rectal bleeding: a neural network approach

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Florian; Gulliford, Sarah L; Webb, Steve; Partridge, Mike [Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey SM2 5PT (United Kingdom)], E-mail: florian.buttner@icr.ac.uk

    2009-09-07

    The incidence of late-toxicities after radiotherapy can be modelled based on the dose delivered to the organ under consideration. Most predictive models reduce the dose distribution to a set of dose-volume parameters and do not take the spatial distribution of the dose into account. The aim of this study was to develop a classifier predicting radiation-induced rectal bleeding using all available information on the dose to the rectal wall. The dose was projected on a two-dimensional dose-surface map (DSM) by virtual rectum-unfolding. These DSMs were used as inputs for a classification method based on locally connected neural networks. In contrast to fully connected conventional neural nets, locally connected nets take the topology of the input into account. In order to train the nets, data from 329 patients from the RT01 trial (ISRCTN 47772397) were split into ten roughly equal parts. By using nine of these parts as a training set and the remaining part as an independent test set, a ten-fold cross-validation was performed. Ensemble learning was used and 250 nets were built from randomly selected patients from the training set. Out of these 250 nets, an ensemble of expert nets was chosen. The performances of the full ensemble and of the expert ensemble were quantified by using receiver-operator-characteristic (ROC) curves. In order to quantify the predictive power of the shape, ensembles of fully connected conventional neural nets based on dose-surface histograms (DSHs) were generated and their performances were quantified. The expert ensembles performed better than or equally as well as the full ensembles. The area under the ROC curve for the DSM-based expert ensemble was 0.64. The area under the ROC curve for the DSH-based expert ensemble equalled 0.59. This difference in performance indicates that not only volumetric, but also morphological aspects of the dose distribution are correlated to rectal bleeding after radiotherapy. Thus, the shape of the dose

  2. Nitrogen oxides emissions from thermal power plants in china: current status and future predictions.

    Science.gov (United States)

    Tian, Hezhong; Liu, Kaiyun; Hao, Jiming; Wang, Yan; Gao, Jiajia; Qiu, Peipei; Zhu, Chuanyong

    2013-10-01

    Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unit-based method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.

  3. Changing currents: a strategy for understanding and predicting the changing ocean circulation.

    Science.gov (United States)

    Bryden, Harry L; Robinson, Carol; Griffiths, Gwyn

    2012-12-13

    Within the context of UK marine science, we project a strategy for ocean circulation research over the next 20 years. We recommend a focus on three types of research: (i) sustained observations of the varying and evolving ocean circulation, (ii) careful analysis and interpretation of the observed climate changes for comparison with climate model projections, and (iii) the design and execution of focused field experiments to understand ocean processes that are not resolved in coupled climate models so as to be able to embed these processes realistically in the models. Within UK-sustained observations, we emphasize smart, cost-effective design of the observational network to extract maximum information from limited field resources. We encourage the incorporation of new sensors and new energy sources within the operational environment of UK-sustained observational programmes to bridge the gap that normally separates laboratory prototype from operational instrument. For interpreting the climate-change records obtained through a variety of national and international sustained observational programmes, creative and dedicated UK scientists should lead efforts to extract the meaningful signals and patterns of climate change and to interpret them so as to project future changes. For the process studies, individual scientists will need to work together in team environments to combine observational and process modelling results into effective improvements in the coupled climate models that will lead to more accurate climate predictions.

  4. Current and Future Applications of Biomedical Engineering for Proteomic Profiling: Predictive Biomarkers in Neuro-Traumatology

    Directory of Open Access Journals (Sweden)

    Mario Ganau

    2018-02-01

    Full Text Available This systematic review aims to summarize the impact of nanotechnology and biomedical engineering in defining clinically meaningful predictive biomarkers in patients with traumatic brain injury (TBI, a critical worldwide health problem with an estimated 10 billion people affected annually worldwide. Data were collected through a review of the existing English literature performed on Scopus, MEDLINE, MEDLINE in Process, EMBASE, and/or Cochrane Central Register of Controlled Trials. Only experimental articles revolving around the management of TBI, in which the role of new devices based on innovative discoveries coming from the field of nanotechnology and biomedical engineering were highlighted, have been included and analyzed in this study. Based on theresults gathered from this research on innovative methods for genomics, epigenomics, and proteomics, their future application in this field seems promising. Despite the outstanding technical challenges of identifying reliable biosignatures for TBI and the mixed nature of studies herein described (single cells proteomics, biofilms, sensors, etc., the clinical implementation of those discoveries will allow us to gain confidence in the use of advanced neuromonitoring modalities with a potential dramatic improvement in the management of those patients.

  5. Protein structural transition at negatively charged electrode surfaces. Effects of temperature and current density

    Czech Academy of Sciences Publication Activity Database

    Černocká, Hana; Ostatná, Veronika; Paleček, Emil

    2015-01-01

    Roč. 174, AUG 2015 (2015), s. 356-360 ISSN 0013-4686 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA ČR(CZ) GA15-15479S; GA ČR(CZ) GA13-00956S Institutional support: RVO:68081707 Keywords : Bovine serum albumin * sensing of surface-attached protein stability * protein structural transition at Hg Subject RIV: BO - Biophysics Impact factor: 4.803, year: 2015

  6. Current and predicted trends in the production, consumption and trade of live animals and their products.

    Science.gov (United States)

    Narrod, C; Tiongco, M; Scott, R

    2011-04-01

    Changes in livestock production, driven by both demand- and supply-side factors, have been significant worldwide. Though historically the developed world was a large supplier of meat and livestock for the developing world, the developing world has rapidly increased production and is meeting more of its growing domestic demand. Many regions of the developing world, however, do not produce enough currently to meet their domestic demand and continue to import more than they produce. There are exceptions, such as Brazil, Thailand, the People's Republic of China and India, where growth in livestock production has been rapid. It is anticipated that in the future many of the developing countries will increase domestic production to meet growing domestic demand. By 2030, beef will probably still be the most significant meat import of developing countries and milk will have more than doubled as a net export of the developed world.

  7. Genetic testing to predict sudden cardiac death: current perspectives and future goals

    Directory of Open Access Journals (Sweden)

    Silvia G. Priori

    2014-01-01

    Full Text Available It is known that monogenic traits may predispose young and otherwise healthy individuals to die suddenly. Diseases such as Long QT Syndrome, Brugada Syndrome and Arrhythmogenic Right Ventricular Cardiomyopathy are well known causes of arrhythmic death in young individuals. For several years the concept of “genetic predisposition” to sudden cardiac death has been limited to these uncommon diseases. In the last few years clinical data have supported the view that risk of dying suddenly may cluster in families, supporting the hypothesis of a genetic component for sudden cardiac death. In this review I will try to provide an overview of current knowledge about genetics of sudden death. I will approach this topic by discussing first where we stand in the use of genetics for risk stratification and therapy selection in monogenic diseases and I will then move to discuss the contribution of genetics to patient profiling in acquired cardiovascular diseases.

  8. Current Distribution over the Electrode Surface in a Lead-acid Cell during Discharge

    Czech Academy of Sciences Publication Activity Database

    Král, P.; Křivák, P.; Bača, P.; Calábek, M.; Micka, Karel

    2002-01-01

    Roč. 105, č. 1 (2002), s. 34-44 ISSN 0378-7753 R&D Projects: GA ČR GA102/98/1170 Institutional research plan: CEZ:AV0Z4040901 Keywords : grid design * current distribution * lead-acid cell Subject RIV: CG - Electrochemistry Impact factor: 1.777, year: 2002

  9. Current distribution over the electrode surface in a cylindrical VRLA cell during discharge

    Czech Academy of Sciences Publication Activity Database

    Křivák, P.; Bača, P.; Calábek, M.; Micka, Karel; Král, P.

    2006-01-01

    Roč. 154, č. 2 (2006), s. 518-522 ISSN 0378-7753 Grant - others:Advanced Lead-Acid Battery Consortium(ES) N4.2 Institutional research plan: CEZ:AV0Z40400503 Keywords : grid design * current distribution * cylindrical lead-acid cell Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.521, year: 2006

  10. Predicting Fire Season Severity in South America Using Sea Surface Temperature Anomalies

    Science.gov (United States)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.; Jin, Yufang; DeFries, Ruth S.; Collatz, George J.; Kasibhatla, Prasad S.; Giglio, Louis; Jin, Yufang; Marlier, Miriam

    2011-01-01

    Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. Here we investigated the relationship between year-to-year changes in satellite-derived estimates of fire activity in South America and sea surface temperature (SST) anomalies. We found that the Oceanic Ni o Index (ONI) was correlated with interannual fire activity in the eastern Amazon whereas the Atlantic Multidecadal Oscillation (AMO) index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model that predicted regional annual fire season severity (FSS) with 3-5 month lead times. Our approach provides the foundation for an early warning system for forecasting the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for mitigation of greenhouse gas and air pollutant emissions.

  11. A simple mathematical model to predict sea surface temperature over the northwest Indian Ocean

    Science.gov (United States)

    Noori, Roohollah; Abbasi, Mahmud Reza; Adamowski, Jan Franklin; Dehghani, Majid

    2017-10-01

    A novel and simple mathematical model was developed in this study to enhance the capacity of a reduced-order model based on eigenvectors (RMEV) to predict sea surface temperature (SST) in the northwest portion of the Indian Ocean, including the Persian and Oman Gulfs and Arabian Sea. Developed using only the first two of 12,416 possible modes, the enhanced RMEV closely matched observed daily optimum interpolation SST (DOISST) values. Spatial distribution of the first mode indicated the greatest variations in DOISST occurred in the Persian Gulf. Also, the slightly increasing trend in the temporal component of the first mode observed in the study area over the last 34 years properly reflected the impact of climate change and rising DOISST. Given its simplicity and high level of accuracy, the enhanced RMEV can be applied to forecast DOISST in oceans, which the poor forecasting performance and large computational-time of other numerical models may not allow.

  12. Power Prediction Model for Turning EN-31 Steel Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    M. Hameedullah

    2010-01-01

    Full Text Available Power consumption in turning EN-31 steel (a material that is most extensively used in automotive industry with tungstencarbide tool under different cutting conditions was experimentally investigated. The experimental runs were planned accordingto 24+8 added centre point factorial design of experiments, replicated thrice. The data collected was statisticallyanalyzed using Analysis of Variance technique and first order and second order power consumption prediction models weredeveloped by using response surface methodology (RSM. It is concluded that second-order model is more accurate than thefirst-order model and fit well with the experimental data. The model can be used in the automotive industries for decidingthe cutting parameters for minimum power consumption and hence maximum productivity

  13. Using surrogate modeling in the prediction of fibrinogen adsorption onto polymer surfaces.

    Science.gov (United States)

    Smith, Jack R; Knight, Doyle; Kohn, Joachim; Rasheed, Khaled; Weber, Norbert; Kholodovych, Vladyslav; Welsh, William J

    2004-01-01

    We present a Surrogate (semiempirical) Model for prediction of protein adsorption onto the surfaces of biodegradable polymers that have been designed for tissue engineering applications. The protein used in these studies, fibrinogen, is known to play a key role in blood clotting. Therefore, fibrinogen adsorption dictates the performance of implants exposed to blood. The Surrogate Model combines molecular modeling, machine learning and an Artificial Neural Network. This novel approach includes an accounting for experimental error using a Monte Carlo analysis. Briefly, measurements of human fibrinogen adsorption were obtained for 45 polymers. A total of 106 molecular descriptors were generated for each polymer. Of these, 102 descriptors were computed using the Molecular Operating Environment (MOE) software based upon the polymer chemical structures, two represented different monomer types, and two were measured experimentally. The Surrogate Model was developed in two stages. In the first stage, the three descriptors with the highest correlation to adsorption were determined by calculating the information gain of each descriptor. Here a Monte Carlo approach enabled a direct assessment of the effect of the experimental uncertainty on the results. The three highest-ranking descriptors, defined as those with the highest information gain for the sample set, were then selected as the input variables for the second stage, an Artificial Neural Network (ANN) to predict fibrinogen adsorption. The ANN was trained using one-half of the experimental data set (the training set) selected at random. The effect of experimental error on predictive capability was again explored using a Monte Carlo analysis. The accuracy of the ANN was assessed by comparison of the predicted values for fibrinogen adsorption with the experimental data for the remaining polymers (the validation set). The mean value of the Pearson correlation coefficient for the validation data sets was 0.54 +/- 0.12. The

  14. Analytical model for Transient Current Technique (TCT) signal prediction and analysis for thin interface characterization

    Science.gov (United States)

    Bronuzzi, J.; Mapelli, A.; Sallese, J. M.

    2016-12-01

    A silicon wafer bonding technique has been recently proposed for the fabrication of monolithic silicon radiation detectors. This new process would enable direct bonding of a read-out electronic chip wafer on a highly resistive silicon substrate wafer. Therefore, monolithic silicon detectors could be fabricated in this way which would allow the free choice of electronic chips and high resistive silicon bulk, even from different providers. Moreover, a monolithic detector with a high resistive bulk would also be available. Electrical properties of the bonded interface are then critical for this application. Indeed, mobile charges generated by radiation inside the bonded bulk are expected to transit through the interface to be collected by the read-out electronics. In order to characterize this interface, the concept of Transient Current Technique (TCT) has been explored by means of numerical simulations combined with a physics based analytical model. In this work, the analytical model giving insight into the physics behind the TCT dependence upon interface traps is validated using both TCAD simulations and experimental measurements.

  15. Estimated maximal and current brain volume predict cognitive ability in old age.

    Science.gov (United States)

    Royle, Natalie A; Booth, Tom; Valdés Hernández, Maria C; Penke, Lars; Murray, Catherine; Gow, Alan J; Maniega, Susana Muñoz; Starr, John; Bastin, Mark E; Deary, Ian J; Wardlaw, Joanna M

    2013-12-01

    Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Estimated maximal and current brain volume predict cognitive ability in old age

    Science.gov (United States)

    Royle, Natalie A.; Booth, Tom; Valdés Hernández, Maria C.; Penke, Lars; Murray, Catherine; Gow, Alan J.; Maniega, Susana Muñoz; Starr, John; Bastin, Mark E.; Deary, Ian J.; Wardlaw, Joanna M.

    2013-01-01

    Brain tissue deterioration is a significant contributor to lower cognitive ability in later life; however, few studies have appropriate data to establish how much influence prior brain volume and prior cognitive performance have on this association. We investigated the associations between structural brain imaging biomarkers, including an estimate of maximal brain volume, and detailed measures of cognitive ability at age 73 years in a large (N = 620), generally healthy, community-dwelling population. Cognitive ability data were available from age 11 years. We found positive associations (r) between general cognitive ability and estimated brain volume in youth (male, 0.28; females, 0.12), and in measured brain volume in later life (males, 0.27; females, 0.26). Our findings show that cognitive ability in youth is a strong predictor of estimated prior and measured current brain volume in old age but that these effects were the same for both white and gray matter. As 1 of the largest studies of associations between brain volume and cognitive ability with normal aging, this work contributes to the wider understanding of how some early-life factors influence cognitive aging. PMID:23850342

  17. Current and predicted demographics of high myopia and an update of its associated pathological changes.

    Science.gov (United States)

    Verkicharla, Pavan Kumar; Ohno-Matsui, Kyoko; Saw, Seang Mei

    2015-09-01

    Excessive axial elongation of the eye in high myopia can cause biomechanical stretching leading to various ocular complications. The purpose of this review is to provide an update on various pathologic changes, especially in the chorio-retina and sclera that have been reported recently using advanced ophthalmic bio-imaging modalities such as optical coherence tomography, magnetic resonance imaging and fundus photography. The prevalence rates of pathologic myopia (myopic retinopathy and maculopathy) mirror the prevalence rates of high myopia as the risks of pathologic myopia increase with high myopia. Peripapillary and sub-foveal choroidal thinning, scleral thinning, and deformed/irregular eye shapes were found to be strongly associated with various pathologic myopic lesions, especially with posterior staphyloma and chorio-retinal atrophy. Considering the increasing prevalence rate of myopia and pathologic myopia, these degenerative changes are likely to increase dramatically over the next few decades due to the rapid growth in the number of individuals with high myopia and the ageing population. The current prevalence rates of pathologic myopia in older adults might have significantly underestimated the future prevalence rates and warrants age of onset of myopia being considered a major risk factor for pathologic myopia. Using advanced technology, identification of novel quantifiable chorio-retinal and scleral parameters in pathologic myopia would help to identify people at risk of developing pathologic myopia and potentially may revolutionise the management of myopia especially in risk prognostication and monitoring of disease progression. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

  18. Pharmacogenetic Biomarkers to Predict Treatment Response in Multiple Sclerosis: Current and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Patricia K. Coyle

    2017-01-01

    Full Text Available Disease-modifying therapies (DMTs have significantly advanced the treatment of relapsing multiple sclerosis (MS, decreasing the frequency of relapses, disability, and magnetic resonance imaging lesion formation. However, patients’ responses to and tolerability of DMTs vary considerably, creating an unmet need for biomarkers to identify likely responders and/or those who may have treatment-limiting adverse reactions. Most studies in MS have focused on the identification of pharmacogenetic markers, using either the candidate-gene approach, which requires prior knowledge of the genetic marker and its role in the target disease, or genome-wide association, which examines multiple genetic variants, typically single nucleotide polymorphisms (SNPs. Both approaches have implicated numerous alleles and SNPs in response to selected MS DMTs. None have been validated for use in clinical practice. This review covers pharmacogenetic markers in clinical practice in other diseases and then reviews the current status of MS DMT markers (interferon β, glatiramer acetate, and mitoxantrone. For a complex disease such as MS, multiple biomarkers may need to be evaluated simultaneously to identify potential responders. Efforts to identify relevant biomarkers are underway and will need to be expanded to all MS DMTs. These will require extensive validation in large patient groups before they can be used in clinical practice.

  19. Semianalytical model predicting transfer of volatile pollutants from groundwater to the soil surface.

    Science.gov (United States)

    Atteia, Olivier; Höhener, Patrick

    2010-08-15

    Volatilization of toxic organic contaminants from groundwater to the soil surface is often considered an important pathway in risk analysis. Most of the risk models use simplified linear solutions that may overpredict the volatile flux. Although complex numerical models have been developed, their use is restricted to experienced users and for sites where field data are known in great detail. We present here a novel semianalytical model running on a spreadsheet that simulates the volatilization flux and vertical concentration profile in a soil based on the Van Genuchten functions. These widely used functions describe precisely the gas and water saturations and movement in the capillary fringe. The analytical model shows a good accuracy over several orders of magnitude when compared to a numerical model and laboratory data. The effect of barometric pumping is also included in the semianalytical formulation, although the model predicts that barometric pumping is often negligible. A sensitivity study predicts significant fluxes in sandy vadose zones and much smaller fluxes in other soils. Fluxes are linked to the dimensionless Henry's law constant H for H < 0.2 and increase by approximately 20% when temperature increases from 5 to 25 degrees C.

  20. Response surface and neural network based predictive models of cutting temperature in hard turning

    Directory of Open Access Journals (Sweden)

    Mozammel Mia

    2016-11-01

    Full Text Available The present study aimed to develop the predictive models of average tool-workpiece interface temperature in hard turning of AISI 1060 steels by coated carbide insert. The Response Surface Methodology (RSM and Artificial Neural Network (ANN were employed to predict the temperature in respect of cutting speed, feed rate and material hardness. The number and orientation of the experimental trials, conducted in both dry and high pressure coolant (HPC environments, were planned using full factorial design. The temperature was measured by using the tool-work thermocouple. In RSM model, two quadratic equations of temperature were derived from experimental data. The analysis of variance (ANOVA and mean absolute percentage error (MAPE were performed to suffice the adequacy of the models. In ANN model, 80% data were used to train and 20% data were employed for testing. Like RSM, herein, the error analysis was also conducted. The accuracy of the RSM and ANN model was found to be ⩾99%. The ANN models exhibit an error of ∼5% MAE for testing data. The regression coefficient was found to be greater than 99.9% for both dry and HPC. Both these models are acceptable, although the ANN model demonstrated a higher accuracy. These models, if employed, are expected to provide a better control of cutting temperature in turning of hardened steel.

  1. Growth of DySi sub 2 layers on Si surface by high-current Dy-ion implantation

    CERN Document Server

    Cheng, X Q

    2003-01-01

    We report, in this paper, the synthesis of DySi sub 2 layers on Si surfaces by high-current Dy-ion implantation in Si wafers using a metal vapor vacuum arc ion source. It was found that the continuous DySi sub 2 layers could grow at a relatively low formation temperature of 190degC and that the surface morphology varied with the variation of the implantation parameters. The formation mechanism of the equilibrium DySi sub 2 phase as well as the continuous DySi sub 2 layer on Si surface is proposed in terms of ion beam heating and the effect of ion dose on the Dy-ion implantation process. (author)

  2. Distributions of the ion temperature, ion pressure, and electron density over the current sheet surface

    Energy Technology Data Exchange (ETDEWEB)

    Kyrie, N. P., E-mail: kyrie@fpl.gpi.ru; Markov, V. S., E-mail: natalya.kyrie@yandex.ru; Frank, A. G.; Vasilkov, D. G.; Voronova, E. V. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2016-06-15

    The distributions of the ion temperature, ion pressure, and electron density over the width (the major transverse dimension) of the current sheet have been studied for the first time. The current sheets were formed in discharges in argon and helium in 2D and 3D magnetic configurations. It is found that the temperature of argon ions in both 2D and 3D magnetic configurations is almost uniform over the sheet width and that argon ions are accelerated by the Ampère force. In contrast, the distributions of the electron density and the temperature of helium ions are found to be substantially nonuniform. As a result, in the 2D magnetic configuration, the ion pressure gradient across the sheet width makes a significant contribution (comparable with the Ampère force) to the acceleration of helium ions, whereas in the 3D magnetic configuration, the Ampère force is counterbalanced by the pressure gradient.

  3. GEOS-3 ocean current investigation using radar altimeter profiling. [Gulf Stream surface topography

    Science.gov (United States)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1978-01-01

    Both quasi-stationary and dynamic departures from the marine geoid were successfully detected using altitude measurements from the GEOS-3 radar altimeter. The quasi-stationary departures are observed either as elevation changes in single pass profiles across the Gulf Stream or at the crowding of contour lines at the western and northern areas of topographic maps generated using altimeter data spanning one month or longer. Dynamic features such as current meandering and spawned eddies can be monitored by comparing monthly mean maps. Comparison of altimeter inferred eddies with IR detected thermal rings indicates agreement of the two techniques. Estimates of current velocity are made using derived slope estimates in conjunction with the geostrophic equation.

  4. Comparison of Approaches to the Prediction of Surface Wave Phase Velocity

    Science.gov (United States)

    Godfrey, K. E.; Dalton, C. A.; Hjorleifsdottir, V.; Ekstrom, G.

    2017-12-01

    Global seismic models provide crucial information about the state, composition, and dynamics of the Earth's interior, and in the shallow mantle these models are primarily constrained by observations of surface waves. Models developed by different groups have been constructed using different data sets and different techniques. While these models exhibit good agreement on the long-wavelength features, there is less consistency in the patterns and amplitude of smaller-scale heterogeneity. Here we investigate how approximations in the theoretical treatment of wave propagation and excitation influence the interpretation of measured phase delays and the tomographic images that result from inverting them. Synthetic seismograms were generated using SPECFEM3D_GLOBE for 42 earthquakes, 134 receiver locations, and two 3-D models of elastic Earth structure: S362ANI (Kustowski et al., 2008) and a rougher model constructed by adding realistic small-scale structure to S362ANI. Fundamental-mode Rayleigh and Love wave phase delays in the period range 35-250 seconds were measured using the approach of Ekström et al. (1997), for which PREM is the assumed reference Earth model. These measurements were compared to phase-delay predictions generated for the great-circle ray approximation, exact ray theory, and finite-frequency theory. We find that for both 3-D earth models exact ray theory provides the best fit to the measurements at short periods. At longer periods finite frequency theory provides the best fit. For the smooth earth model, the differences in fit for the various predictions are less significant at long periods than at shorter periods. The differences at long periods become more significant with increasing model roughness. In all cases, the agreement between predictions and measurements is best for paths located away from nodes in the source radiation pattern. The ability of the measured phase delays to recover the input Earth models is assessed through tests that explore

  5. Prediction of the antiglycation activity of polysaccharides from Benincasa hispida using a response surface methodology.

    Science.gov (United States)

    Jiang, Xiang; Kuang, Fei; Kong, Fansheng; Yan, Chunyan

    2016-10-20

    Benincasa hispida is a popular vegetable in China. Our previous experiments suggested that polysaccharides isolated from B. hispida fruits (PBH) have antiglycation effect and DPPH free radical scavenging activity. Ultrasonic treatments can be used to extract polysaccharides from Benincasa hispida (PBH). The aim of this study was to investigate the correlation between the ultrasonic treatment conditions and the antiglycation activity of PBH. A mathematical model was generated with an artificial neural network (ANN) toolbox from MATLAB to analyze the effects of ultrasonic treatment conditions on antiglycation activity. The response surface plots showed relationships between ultrasonic extraction conditions and bioactivity. The R(2) value of the model was 0.9919, which suggested good fitness of the neural network. The application of genetic algorithms showed that the optimal ultrasonic extraction conditions resulted in the highest antiglycation activity for PBH. These were 150W, 46°C, and 35min. These conditions produced a predicted antiglycation activity of 41.2%; the actual activity was 40.9% under optimal conditions. This is very close to the predicted value. The experimental data indicated that the PBH possessed both antiglycation and antioxidant activities. The maximum actual value of antiglycation was 101.7% that of the positive control, and the PBH inhibited the DPPH free radicals with an EC50 value of 0.98mg/mL. This is 66.2% that of ascorbic acid. These results explained the observations that B. hispida can decrease glucose levels in diabetic patients. The experimental results also showed that the ANN could be used for optimization and prediction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Brain Surface Current Density Mapping in Pianists and Non-Pianists

    Science.gov (United States)

    2001-10-25

    while listening to piano pieces. Keywords - Inverse problems, Biomagnetism I. INTRODUCTION In magnetoencephalography (MEG), one of the common...Number Author(s) Project Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Biomagnetic Center Friedrich-Schiller...Haueisen, H. Nowak, and H. Brauer, “Equivalent Ellipsoid as an interpretation tool of extended current distributions in biomagnetic inverse problems,” IEEE Trans. Mag., vol. 36, pp. 1692 – 1695, 2000

  7. Design Guidelines for Impressed-Current Cathodic Protection Systems on Surface-Effect Ships

    Science.gov (United States)

    1975-05-01

    result, design data, particularly regarding current levels and means to avoid overprotection corrosion, and design procedures have been pre- viously...degradation due to overprotection corrosion. To determine the limit of overprotection at high velocity, experiments were run on 1- x 4-inch aluminum... OVERPROTECTION EXPERIMENTS Potential Weight Corrosion mV Loss, g Rate, MPY specimen Appearance 1 •120C • ?5C 52.4 No visible corrosion , -I25O 0

  8. Low-cost surface reconstruction for aesthetic results assessment and prediction in breast cancer surgery.

    Science.gov (United States)

    Lacher, Rene M; Hipwell, John H; Williams, Norman R; Keshtgar, Mohammed R S; Hawkes, David J; Stoyanov, Danail

    2015-08-01

    The high incidence and low mortality of breast cancer surgery has led to an increasing emphasis on the cosmetic outcome of surgical treatment. Advances in aesthetic evaluation, as well as surgical planning and outcome prediction, have been investigated by using geometrically precise 3D modelling of the breast surface prior to surgery and after the procedure. However, existing solutions are based on expensive site specific setups and remain weakly validated. In this paper, we explore the possibility of using low-cost RGBD cameras as an affordable and mobile system for breast surface reconstruction. The methodology relies on sensor calibration, uncertainty-driven point filtering, dense reconstruction and subsequent multi-view joint optimization to diffuse residual pose errors. Results from a phantom study, with ground truth obtained through commercially available scanners, indicate that the approach is promising with RMS errors in order of 2 mm. A clinical study shows the practical applicability of our method and compares favourably to high-end scanning solutions.

  9. Colloid filtration in surface dense vegetation: experimental results and theoretical predictions.

    Science.gov (United States)

    Wu, Lei; Muñoz-Carpena, Rafael; Gao, Bin; Yang, Wen; Pachepsky, Yakov A

    2014-04-01

    Understanding colloid and colloid-facilitated contaminant transport in overland flow through dense vegetation is important to protect water quality in the environment, especially for water bodies receiving agricultural and urban runoff. In previous studies, a single-stem efficiency theory for rigid and clean stem systems was developed to predict colloid filtration by plant stems of vegetation in laminar overland flow. Hence, in order to improve the accuracy of the single-stem efficiency theory to real dense vegetation system, we incorporated the effect of natural organic matter (NOM) on the filtration of colloids by stems. Laboratory dense vegetation flow chamber experiments and model simulations were used to determine the kinetic deposition (filtration) rate of colloids under various conditions. The results show that, in addition to flow hydrodynamics and solution chemistry, steric repulsion afforded by NOM layer on the plants stem surface also plays a significant role in controlling colloid deposition on vegetation in overland flow. For the first time, a refined single-stem efficiency theory with considerations of the NOM effect is developed that describes the experimental data with good accuracy. This theory can be used to not only help construct and refine mathematical models of colloid transport in real vegetation systems in overland flow, but also inform the development of theories of colloid deposition on NOM-coated surfaces in natural, engineered, and biomedical systems.

  10. Can current moisture responses predict soil CO2 efflux under altered precipitation regimes? A synthesis of manipulation experiments

    DEFF Research Database (Denmark)

    Vicca, S.; Bahn, M.; Estiarte, M.

    2014-01-01

    As a key component of the carbon cycle, soil CO2 efflux (SCE) is being increasingly studied to improve our mechanistic understanding of this important carbon flux. Predicting ecosystem responses to climate change often depends on extrapolation of current relationships between ecosystem processes ...... rejected. Importantly, these were the experiments with the most reliable data sets, i.e., those providing high-frequency measurements of SCE. Regression tree analysis demonstrated that our hypothesis could be rejected only for experiments with measurement intervals of less than 11 days...

  11. Current status of the surface-based investigations in the MIU project

    International Nuclear Information System (INIS)

    Nakano, Katushi; Osawa, Hideaki

    2001-01-01

    Tono Geoscience Center (TGC) has been conducting a wide range of geoscientific research in order to build a firm scientific and technological basis for the research and development of geological disposal. One of the major components of the ongoing geoscientific research program is the Mizunami Underground Research Laboratory (MIU) project in the Tono region, central Japan. The R and D work of the MIU project has the following main goals: Develop comprehensive investigation techniques for the geological environment. Develop a range of engineering techniques for deep underground application. A wide range of geoscientific research and development activities of the MIU project is planned in three phases a 20 years period; Phase one: surface-based investigation. Phase two: construction. Phase three: operations. The MIU site has been investigated by geological, hydrogeological, hydrochemical and rock mechanical surveys on the surface. Based on this information, modeling and simulation works have been conducted in the different investigation stages. Technological knowledge and experience have been accumulated, which allow application of the methodologies and techniques to characterize the deep geological environment in crystalline rock. This report presents the results of the investigations from fiscal 1996 to 1999 in phase one. (author)

  12. Ensemble Data Assimilation to Characterize Surface-Layer Errors In Numerical Weather Prediction Models

    Science.gov (United States)

    Hacker, Joshua; Angevine, Wayne

    2013-04-01

    Experiments with the single-column implementation of the Weather Research and Forecasting mesoscale model provide a basis for deducing land-atmosphere coupling errors in the model. Coupling occurs both through heat and moisture fluxes through the land-atmosphere interface and roughness sub-layer, and turbulent heat, moisture, and momentum fluxes through the atmospheric surface layer. This work primarily addresses the turbulent fluxes, which are parameterized following Monin-Obukhov similarity theory applied to the atmospheric surface layer. By combining ensemble data assimilation and parameter estimation, the model error can be characterized. Ensemble data assimilation of 2-m temperature and water vapor mixing ratio, and 10-m wind components, forces the model to follow observations during a month-long simulation for a column over the well-instrumented ARM Central Facility near Lamont, OK. One-hour errors in predicted observations are systematically small but non-zero, and the systematic errors measure bias as a function of local time of day. Analysis increments for state elements nearby (15-m AGL) can be too small or have the wrong sign, indicating systematically biased covariances and model error. Experiments using the ensemble filter to objectively estimate a parameter controlling the thermal land-atmosphere coupling show that the parameter adapts to offset the model errors, but that the errors cannot be eliminated. Results suggest either structural error or further parametric error that may be difficult to estimate. Experiments omitting atypical observations such as soil and flux measurements lead to qualitatively similar deductions, showing potential for assimilating common in-situ observations as an inexpensive framework for deducing and isolating model errors. We finish by presenting recent results from a deeper examination of the second-moment ensemble statistics, which demonstrate the effect of assimilation on the coupling through the stability function in

  13. Predictability of rainfall and teleconnections patterns influencing on Southwest Europe from sea surfaces temperatures

    Science.gov (United States)

    Lorenzo, M. N.; Iglesias, I.; Taboada, J. J.; Gómez-Gesteira, M.; Ramos, A. M.

    2009-04-01

    This work assesses the possibility of doing a forecast of rainfall and the main teleconnections patterns that influences climate in Southwest Europe by using sea surface temperature anomalies (SSTA). The area under study is located in the NW Iberian Peninsula. This region has a great oceanic influence on its climate and has an important dependency of the water resources. In this way if the different SST patterns are known, the different rainfall situations can be predicted. On the other hand, the teleconnection patterns, which have strong weight on rainfall, are influenced by the SSTA of different areas. In the light of this, the aim of this study is to explore the relationship between global SSTAs, rainfall and the main teleconnection patterns influencing on Europe. The SST data with a 2.0 degree resolution was provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA. A monthly averaged data from 1 January 1951 through December 2006 was considered. The monthly precipitation data from 1951-2006 were obtained from the database CLIMA of the University of Santiago de Compostela with data from the Meteorological State Agency (AEMET) and the Regional Government of Galicia. The teleconnection indices were taken of the Climate Prediction Center of the NOAA between 1950 and 2006. A monthly and seasonal study was analysed considering up to three months of delay in the first case and up to four seasons of delay in the second case. The Pearson product-moment correlation coefficient r was considered to quantify linear associations between SSTA and precipitation and/or SSTA and teleconnection indices. A test for field-significance was applied considering the properties of finiteness and interdependence of the spatial grid to avoid spurious correlations. Analysing the results obtained with the global SSTA and the teleconnection indices, a great number of ocean regions with high correlations can be found. The spatial patterns show very high correlations with Indian Ocean waters

  14. Is the current stress state in the Central Amazonia caused by surface water loading?

    Science.gov (United States)

    Ibanez, Delano M.; Riccomini, Claudio; Miranda, Fernando P.

    2014-11-01

    We present new fault data for the region of the Manaus, Central Amazonia, Brazil. Field measurements concentrate on the Miocene-Holocene sedimentary deposits exposed on the Amazonas River Basin, in order to investigate the development of this region in this time-interval. Two faulting events are distinguished since the Miocene. The oldest one is related to NW-SE extension during Miocene times and associated with paleoseismicity, while the younger is associated with NE-SW extension direction and seems to persist today. These two deformational events may be thereby considered Neotectonic. Moreover, the second extensional pulse with NE-SW orientation can be explained by the surface hydrological loading, which induces the Central Amazonia flexural subsidence and may promote extensional stresses in the upper crust.

  15. Current Hormonal Contraceptive Use Predicts Female Extra-Pair and Dyadic Sexual Behavior: Evidence Based on Czech National Survey Data

    Directory of Open Access Journals (Sweden)

    Kateřina Klapilová

    2014-01-01

    Full Text Available Data from 1155 Czech women (493 using oral contraception, 662 non-users, obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC use on extra-pair and dyadic (in-pair sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length. The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not. However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

  16. Current hormonal contraceptive use predicts female extra-pair and dyadic sexual behavior: evidence based on Czech National Survey data.

    Science.gov (United States)

    Klapilová, Kateřina; Cobey, Kelly D; Wells, Timothy; Roberts, S Craig; Weiss, Petr; Havlíček, Jan

    2014-01-10

    Data from 1155 Czech women (493 using oral contraception, 662 non-users), obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC) use on extra-pair and dyadic (in-pair) sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP) regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length). The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not). However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

  17. Validation of asphalt mixture pavement skid prediction model and development of skid prediction model for surface treatments.

    Science.gov (United States)

    2017-04-01

    Pavement skid resistance is primarily a function of the surface texture, which includes both microtexture and macrotexture. Earlier, under the Texas Department of Transportation (TxDOT) Research Project 0-5627, the researchers developed a method to p...

  18. Sea surface temperature (SST) and surface current data collected from the Mar Mostro during the around-the-world Volvo Ocean Race (VOR) from 2011-11-05 to 2012-07-12 (NCEI Accession 0130694)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Navigation, surface current, sea surface temperature, wind, and atmospheric pressure data collected by the Mar Mostro during the around-the-world Volvo Ocean Race...

  19. Predicting the current and future potential distributions of lymphatic filariasis in Africa using maximum entropy ecological niche modelling.

    Directory of Open Access Journals (Sweden)

    Hannah Slater

    Full Text Available Modelling the spatial distributions of human parasite species is crucial to understanding the environmental determinants of infection as well as for guiding the planning of control programmes. Here, we use ecological niche modelling to map the current potential distribution of the macroparasitic disease, lymphatic filariasis (LF, in Africa, and to estimate how future changes in climate and population could affect its spread and burden across the continent. We used 508 community-specific infection presence data collated from the published literature in conjunction with five predictive environmental/climatic and demographic variables, and a maximum entropy niche modelling method to construct the first ecological niche maps describing potential distribution and burden of LF in Africa. We also ran the best-fit model against climate projections made by the HADCM3 and CCCMA models for 2050 under A2a and B2a scenarios to simulate the likely distribution of LF under future climate and population changes. We predict a broad geographic distribution of LF in Africa extending from the west to the east across the middle region of the continent, with high probabilities of occurrence in the Western Africa compared to large areas of medium probability interspersed with smaller areas of high probability in Central and Eastern Africa and in Madagascar. We uncovered complex relationships between predictor ecological niche variables and the probability of LF occurrence. We show for the first time that predicted climate change and population growth will expand both the range and risk of LF infection (and ultimately disease in an endemic region. We estimate that populations at risk to LF may range from 543 and 804 million currently, and that this could rise to between 1.65 to 1.86 billion in the future depending on the climate scenario used and thresholds applied to signify infection presence.

  20. Decentralized energy management strategy based on predictive controllers for a medium voltage direct current photovoltaic electric vehicle charging station

    International Nuclear Information System (INIS)

    Torreglosa, Juan P.; García-Triviño, Pablo; Fernández-Ramirez, Luis M.; Jurado, Francisco

    2016-01-01

    Highlights: • Electric vehicle charging station supplied by photovoltaic, batteries and grid connection is analyzed. • The bus voltage is the key parameter for controlling the system by decentralized approach. • Decentralized control approach facilities the enlargement of the system. • Photovoltaic and battery systems are controlled by model predictive controllers. • Response by model predictive controllers improves that by PI controllers. - Abstract: The use of distributed charging stations based on renewable energy sources for electric vehicles has increased in recent years. Combining photovoltaic solar energy and batteries as energy storage system, directly tied into a medium voltage direct current bus, and with the grid support, results to be an interesting option for improving the operation and efficiency of electric vehicle charging stations. In this paper, an electric vehicle charging station supplied by photovoltaic solar panels, batteries and with grid connection is analysed and evaluated. A decentralized energy management system is developed for regulating the energy flow among the photovoltaic system, the battery and the grid in order to achieve the efficient charging of electric vehicles. The medium voltage direct current bus voltage is the key parameter for controlling the system. The battery is controlled by a model predictive controller in order to keep the bus voltage at its reference value. Depending on the state-of-charge of the battery and the bus voltage, the photovoltaic system can work at maximum power point tracking mode or at bus voltage sustaining mode, or even the grid support can be needed. The results demonstrate the proper operation and energy management of the electric vehicle charging station under study.

  1. Improving prediction of pesticide drift deposition on water surfaces on the Colombian highlands

    Science.gov (United States)

    Garcia-Santos, Glenda; Feola, Giusppe; Binder, Claudia R.

    2010-05-01

    Assessment of the environmental risk of new agricultural pesticides in Colombia may be highly underestimated. Control and registration of new pesticides is regulated by the Andean technical manual, which calculates the expected drift concentration expressed as the percentage of the applied dose. The calculations are based on tables with drift values depending on the crop type and the distance of the water surface from the field border based on the model proposed by Ganzelmeier et al. (1995). However, in the Andean region, the application techniques, agricultural practices and meteorological conditions usually significantly differ from those for which the model was designed. Therefore, the use of the tables based on Ganzelmeier et al. (1995) in the Andean manual might be producing an important disagreement between the actual and the expected pesticide concentration in water surfaces close to the treated field. The objectives of this study were i) to improve the understanding of the main factors influencing the mass fluxes (i.e. drift deposition), ii) to assess the suitability of the model proposed in the Andean technical manual for potato crops and other existing models under meteorological conditions and application practices of smallholding potato growers on the Colombian Andes, and iii) to propose a new model of drift deposition which performs better under such conditions. The study was carried out among smallholder potato producers in the Department of Boyaca, Colombia. 12 trials were carried out with a local farmer using his knapsack sprayer. Spray relative drift deposition was measured using the tracer Uranine. The main factors influencing drift were distance from the field border, wind speed and vapour pressure deficit. The data obtained in this study demonstrated that drift calculated with the Andean technical manual's tables was highly underestimated (>200 %). A similar underestimation was observed also for other existing models. However, calibration of

  2. Combustion of methane-oxygen and methane-oxygen-CFC mixtures initiated by a high-current slipping surface discharge

    International Nuclear Information System (INIS)

    Kossyi, I.A.; Silakov, V.P.; Tarasova, N.M.

    2001-01-01

    Results are presented from experimental studies of the destruction of chlorofluorocarbon (CF 2 Cl 2 ) molecules in a methane-oxygen (air) gas mixture whose combustion is initiated by a high-current slipping surface discharge. It is found that a three-component CH 4 + O 2 (air)+ CF 2 Cl 2 gas mixture (even with a considerable amount of the third component) demonstrates properties of explosive combustion involving chain reactions that are typical of two-component CH 4 + O 2 mixtures. Experiments show the high degree of destruction (almost complete decomposition) of chlorofluorocarbons contained in the mixture during one combustion event. The combustion dynamics is studied. It is shown that the combustion initiated by a slipping surface discharge has a number of characteristic features that make it impossible to identify the combustion dynamics with the formation of a combustion or detonation wave. The features of the effects observed can be related to intense UV radiation produced by a pulsed high-current surface discharge

  3. Surface gas pollutants in Lhasa, a highland city of Tibet: current levels and pollution implications

    Science.gov (United States)

    Ran, L.; Lin, W. L.; Deji, Y. Z.; La, B.; Tsering, P. M.; Xu, X. B.; Wang, W.

    2014-05-01

    Through several years of development, the city of Lhasa has become one of the most populated and urbanized areas on the highest plateau in the world. In the process of urbanization, current and potential air quality issues have been gradually concerned. To investigate the current status of air pollution in Lhasa, various gas pollutants including NOx, CO, SO2 and O3 were continuously measured from June 2012 to May 2013 at an urban site (29.40° N, 91.08° E, 3650 m a.s.l.). The seasonal variations of primary gas pollutants exhibited a peak from November to January with a large variability. High concentrations of primary trace gases almost exclusively occurred under low wind speed and showed no distinct dependence on wind direction, implying local urban emissions to be predominant. A comparison of NO2, CO and SO2 concentrations in summer between 1998 and 2012 indicated a significant increase in emissions of these gas pollutants and a change in their intercorrelations, as a result of a substantial growth in the demand of energy consumption using fossil fuels instead of previously widely used biofuels. The pronounced diurnal double peaks of primary trace gases in all seasons suggested automobile exhaust to be a major emission source in Lhasa. The secondary gas pollutant O3 displayed an average diurnal cycle of a shallow flat peak for about 4-5 h in the afternoon and a minimum in the early morning. Nighttime O3 was sometimes completely consumed by the high level of NOx. Seasonally, the variations of O3 concentrations displayed a low valley in winter and a peak in spring. In autumn and winter, transport largely contributed to the observed O3 concentrations, given its dependence on wind speed and wind direction, while in spring and summer photochemistry played an important role. A more efficient buildup of O3 concentrations in the morning and a higher peak in the afternoon was found in summer 2012 than in 1998. An enhancement in O3 concentrations would be expected in the

  4. Surface gas pollutants in Lhasa, a highland city of Tibet - current levels and pollution implications

    Science.gov (United States)

    Ran, L.; Lin, W. L.; Deji, Y. Z.; La, B.; Tsering, P. M.; Xu, X. B.; Wang, W.

    2014-10-01

    Through several years of development, the city of Lhasa has become one of the most populated and urbanized areas on the highest plateau in the world. In the process of urbanization, current and potential air quality issues have been gradually concerned. To investigate the current status of air pollution in Lhasa, various gas pollutants including NOx, CO, SO2, and O3, were continuously measured from June 2012 to May 2013 at an urban site (29.40° N, 91.08° E, 3650 m a.s.l.). The seasonal variations of primary gas pollutants exhibited a peak from November to January with a large variability. High mixing ratios of primary trace gases almost exclusively occurred under low wind speed and showed no distinct dependence on wind direction, implying local urban emissions to be predominant. A comparison of NO2, CO, and SO2 mixing ratios in summer between 1998 and 2012 indicated a significant increase in emissions of these gas pollutants and a change in their intercorrelations, as a result of a substantial growth in the demand of energy consumption using fossil fuels instead of previously widely used biomass. The pronounced diurnal double peaks of primary trace gases in all seasons suggested automobile exhaust to be a major emission source in Lhasa. The secondary gas pollutant O3 displayed an average diurnal cycle of a shallow flat peak for about 4-5 h in the afternoon and a minimum in the early morning. Nighttime O3 was sometimes completely consumed by the high level of NOx. Seasonally, the variations of O3 mixing ratios displayed a low valley in winter and a peak in spring. In autumn and winter, transport largely contributed to the observed O3 mixing ratios, given its dependence on wind speed and wind direction, while in spring and summer photochemistry played an important role. A more efficient buildup of O3 mixing ratios in the morning and a higher peak in the afternoon was found in summer 2012 than in 1998. An enhancement in O3 mixing ratios would be expected in the

  5. Exonic Splicing Mutations Are More Prevalent than Currently Estimated and Can Be Predicted by Using In Silico Tools.

    Directory of Open Access Journals (Sweden)

    Omar Soukarieh

    2016-01-01

    Full Text Available The identification of a causal mutation is essential for molecular diagnosis and clinical management of many genetic disorders. However, even if next-generation exome sequencing has greatly improved the detection of nucleotide changes, the biological interpretation of most exonic variants remains challenging. Moreover, particular attention is typically given to protein-coding changes often neglecting the potential impact of exonic variants on RNA splicing. Here, we used the exon 10 of MLH1, a gene implicated in hereditary cancer, as a model system to assess the prevalence of RNA splicing mutations among all single-nucleotide variants identified in a given exon. We performed comprehensive minigene assays and analyzed patient's RNA when available. Our study revealed a staggering number of splicing mutations in MLH1 exon 10 (77% of the 22 analyzed variants, including mutations directly affecting splice sites and, particularly, mutations altering potential splicing regulatory elements (ESRs. We then used this thoroughly characterized dataset, together with experimental data derived from previous studies on BRCA1, BRCA2, CFTR and NF1, to evaluate the predictive power of 3 in silico approaches recently described as promising tools for pinpointing ESR-mutations. Our results indicate that ΔtESRseq and ΔHZEI-based approaches not only discriminate which variants affect splicing, but also predict the direction and severity of the induced splicing defects. In contrast, the ΔΨ-based approach did not show a compelling predictive power. Our data indicates that exonic splicing mutations are more prevalent than currently appreciated and that they can now be predicted by using bioinformatics methods. These findings have implications for all genetically-caused diseases.

  6. Current status of NO{sub x} prediction by conditional moment closure method for turbulent non premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Huh, K.Y. [Pohang Univ. of Science and Technology, Pohang, (Korea, Republic of). Dept. of Mechanical Engineering

    2005-07-01

    Nitrogen oxides (NO{sub x}) are one of the most strictly regulated atmospheric pollutants originating from industrial and automotive combustion processes, and the development of an accurate prediction method has become an urgent research goal in both academic and engineering communities. NO{sub x} emissions are sensitive to most design parameters and operating conditions of combustion devices, since they are controlled by both chemical kinesis and turbulent mixing. This paper presented a summary of the current status of NO{sub x} prediction by the conditional moment closure (CMC) method, as well as details of experiments conducted to validate the CMC method. Recent validation results of first and second order CMC were discussed. It was suggested that given proper information on mixture composition and boundary conditions, it is possible to make accurate predictions of NO{sub x} employing detailed chemical kinetic mechanisms for hydrocarbon oxidation and NO{sub x}, even in extreme cases with significant local extinction. Four test flames were analyzed in this experiment: piloted jet, simple jet, MILD combustion, and bluffbody flames. Results indicate that first order closure is accurate enough for most flames not far from equilibrium, while significant improvements can be made near ignition or extinction limits by second-order closure. The CMC method can be applied to predict NO{sub x} emission in many practical combustion systems involving complicated flow fields. Details of mixing calculations and turbulence models were discussed along with issues concerning flame structure determined by chemistry and scalar dissipation. It was concluded that the CMC method is more accurate than approaches based on unconditional averaging, and computationally more efficient than other transport methods. 15 refs., 6 figs.

  7. Rheumatology in the community of Madrid: current availability of rheumatologists and future needs using a predictive model.

    Science.gov (United States)

    Lázaro y De Mercado, Pablo; Blasco Bravo, Antonio Javier; Lázaro y De Mercado, Ignacio; Castañeda, Santos; López Robledillo, Juan Carlos

    2013-01-01

    To: 1) describe the distribution of the public sector rheumatologists; 2) identify variables on which the workload in Rheumatology depends; and 3) build a predictive model on the need of rheumatologists for the next 10 years, in the Community of Madrid (CM). The information was obtained through structured questionnaires sent to all services/units of Rheumatology of public hospitals in the CM. The population figures, current and forecasted, were obtained from the National Statistics Institute. A predictive model was built based on information about the current and foreseeable supply, current and foreseeable demand, and the assumptions and criteria used to match supply with demand. The underlying uncertainty in the model was assessed by sensitivity analysis. In the CM in 2011 there were 150 staff rheumatologists and 49 residents in 27 centers, which is equivalent to one rheumatologist for every 33,280 inhabitants in the general population, and one for every 4,996 inhabitants over 65 years. To keep the level of assistance of 2011 in 2021 in the general population, it would be necessary to train more residents or hire more rheumatologists in scenarios of demand higher than 15%. However, to keep the level of assistance in the population over 65 years of age it would be necessary to train more residents or hire more specialists even without increased demand. The model developed may be very useful for planning, with the CM policy makers, the needs of human resources in Rheumatology in the coming years. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  8. Polymer on Top: Current Limits and Future Perspectives of Quantitatively Evaluating Surface Grafting.

    Science.gov (United States)

    Michalek, Lukas; Barner, Leonie; Barner-Kowollik, Christopher

    2018-03-07

    Well-defined polymer strands covalently tethered onto solid substrates determine the properties of the resulting functional interface. Herein, the current approaches to determine quantitative grafting densities are assessed. Based on a brief introduction into the key theories describing polymer brush regimes, a user's guide is provided to estimating maximum chain coverage and-importantly-examine the most frequently employed approaches for determining grafting densities, i.e., dry thickness measurements, gravimetric assessment, and swelling experiments. An estimation of the reliability of these determination methods is provided via carefully evaluating their assumptions and assessing the stability of the underpinning equations. A practical access guide for comparatively and quantitatively evaluating the reliability of a given approach is thus provided, enabling the field to critically judge experimentally determined grafting densities and to avoid the reporting of grafting densities that fall outside the physically realistic parameter space. The assessment is concluded with a perspective on the development of advanced approaches for determination of grafting density, in particular, on single-chain methodologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Modeling mechanical signals on the surface of µCT and CAD based rapid prototype scaffold models to predict (early stage) tissue development.

    Science.gov (United States)

    Hendrikson, W J; van Blitterswijk, C A; Verdonschot, N; Moroni, L; Rouwkema, J

    2014-09-01

    In the field of tissue engineering, mechano-regulation theories have been applied to help predict tissue development in tissue engineering scaffolds in the past. For this, finite element models (FEMs) were used to predict the distribution of strains within a scaffold. However, the strains reported in these studies are volumetric strains of the material or strains developed in the extracellular matrix occupying the pore space. The initial phase of cell attachment and growth on the biomaterial surface has thus far been neglected. In this study, we present a model that determines the magnitude of biomechanical signals on the biomaterial surface, enabling us to predict cell differentiation stimulus values at this initial stage. Results showed that magnitudes of the 2D strain--termed surface strain--were lower when compared to the 3D volumetric strain or the conventional octahedral shear strain as used in current mechano-regulation theories. Results of both µCT and CAD derived FEMs from the same scaffold were compared. Strain and fluid shear stress distributions, and subsequently the cell differentiation stimulus, were highly dependent on the pore shape. CAD models were not able to capture the distributions seen in the µCT FEM. The calculated mechanical stimuli could be combined with current mechanobiological models resulting in a tool to predict cell differentiation in the initial phase of tissue engineering. Although experimental data is still necessary to properly link mechanical signals to cell behavior in this specific setting, this model is an important step towards optimizing scaffold architecture and/or stimulation regimes. © 2014 Wiley Periodicals, Inc.

  10. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  11. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    Science.gov (United States)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  12. Experimental assessment of blade tip immersion depth from free surface on average power and thrust coefficients of marine current turbine

    Science.gov (United States)

    Lust, Ethan; Flack, Karen; Luznik, Luksa

    2014-11-01

    Results from an experimental study on the effects of marine current turbine immersion depth from the free surface are presented. Measurements are performed with a 1/25 scale (diameter D = 0.8m) two bladed horizontal axis turbine towed in the large towing tank at the U.S. Naval Academy. Thrust and torque are measured using a dynamometer, mounted in line with the turbine shaft. Shaft rotation speed and blade position are measured using a shaft position indexing system. The tip speed ratio (TSR) is adjusted using a hysteresis brake which is attached to the output shaft. Two optical wave height sensors are used to measure the free surface elevation. The turbine is towed at 1.68 m/s, resulting in a 70% chord based Rec = 4 × 105. An Acoustic Doppler Velocimeter (ADV) is installed one turbine diameter upstream of the turbine rotation plane to characterize the inflow turbulence. Measurements are obtained at four relative blade tip immersion depths of z/D = 0.5, 0.4, 0.3, and 0.2 at a TSR value of 7 to identify the depth where free surface effects impact overall turbine performance. The overall average power and thrust coefficient are presented and compared to previously conducted baseline tests. The influence of wake expansion blockage on the turbine performance due to presence of the free surface at these immersion depths will also be discussed.

  13. WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hao, S.Z., E-mail: ebeam@dlut.edu.cn [Key Laboratory of Materials Modification and School of Physics and Optoelectronics Engineering, Dalian University of Technology, Dalian 116024 (China); Zhang, Y. [Key Laboratory of Materials Modification and School of Physics and Optoelectronics Engineering, Dalian University of Technology, Dalian 116024 (China); School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870 (China); Xu, Y. [Key Laboratory of Materials Modification and School of Physics and Optoelectronics Engineering, Dalian University of Technology, Dalian 116024 (China); College of Materials Science and Engineering, Liaoning Technical University, Fuxin 123000 (China); Gey, N.; Grosdidier, T. [Université de Lorraine, Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Ile du Saulcy, 57045 Metz (France); Université de Lorraine, Laboratoire d’Excellence on Design of Alloy Metals for Low-Mass Structure (DAMAS), Ile du Saulcy, 57045 Metz (France); Dong, C. [Key Laboratory of Materials Modification and School of Physics and Optoelectronics Engineering, Dalian University of Technology, Dalian 116024 (China); Université de Lorraine, Laboratoire d’Excellence on Design of Alloy Metals for Low-Mass Structure (DAMAS), Ile du Saulcy, 57045 Metz (France)

    2013-11-15

    High current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 μs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC{sub 1−x}, Co{sub 3}W{sub 9}C{sub 4}, Co{sub 3}W{sub 3}C phases and graphite precipitate domains ∼50 nm. The friction coefficient of modified surface decreased to ∼0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 × 10{sup −5} mm{sup 3}/min to 6.3 × 10{sup −6} mm{sup 3}/min, showing a significant self-lubricating effect.

  14. Variability and Predictability of West African Droughts. A Review in the Role of Sea Surface Temperature Anomalies

    Science.gov (United States)

    Rodriguez-Fonseca, Belen; Mohino, Elsa; Mechoso, Carlos R.; Caminade, Cyril; Biasutti, Michela; Gaetani, Marco; Garcia-Serrano, J.; Vizy, Edward K.; Cook, Kerry; Xue, Yongkang; hide

    2015-01-01

    The Sahel experienced a severe drought during the 1970s and 1980s after wet periods in the 1950s and 1960s. Although rainfall partially recovered since the 1990s, the drought had devastating impacts on society. Most studies agree that this dry period resulted primarily from remote effects of sea surface temperature (SST) anomalies amplified by local land surface-atmosphere interactions. This paper reviews advances made during the last decade to better understand the impact of global SST variability on West African rainfall at interannual to decadal time scales. At interannual time scales, a warming of the equatorial Atlantic and Pacific/Indian Oceans results in rainfall reduction over the Sahel, and positive SST anomalies over the Mediterranean Sea tend to be associated with increased rainfall. At decadal time scales, warming over the tropics leads to drought over the Sahel, whereas warming over the North Atlantic promotes increased rainfall. Prediction systems have evolved from seasonal to decadal forecasting. The agreement among future projections has improved from CMIP3 to CMIP5, with a general tendency for slightly wetter conditions over the central part of the Sahel, drier conditions over the western part, and a delay in the monsoon onset. The role of the Indian Ocean, the stationarity of teleconnections, the determination of the leader ocean basin in driving decadal variability, the anthropogenic role, the reduction of the model rainfall spread, and the improvement of some model components are among the most important remaining questions that continue to be the focus of current international projects.

  15. Does early family risk and current quality of care predict indiscriminate social behavior in institutionalized Portuguese children?

    Science.gov (United States)

    Soares, Isabel; Belsky, Jay; Oliveira, Paula; Silva, Joana; Marques, Sofia; Baptista, Joana; Martins, Carla

    2014-01-01

    The current study extends research on the effects of institutionalization, most notably by evaluating the influence of proximal relationship processes over and above prenatal and pre-institutional family experiences. By focusing on current quality of institutional care and the child's early family background, it examines the influence of variations in the institutionalization experience on displays of indiscriminate social behavior, after taking into account potentially confounding pre-admission experiences. Seventy-four Portuguese children (11-30 months) placed in 17 residential institutions and their primary caregivers participated in the study. Children's displays of indiscriminate social behavior were assessed based on an observational measure and a semi-structured interview administered to the child's caregiver. Data on children's physical and mental development were also collected. Three contextual-risk composites of early family behavior - prenatal, family relational, and emotional-neglect--were created. The quality of institutional care was examined in terms of structural, relational characteristics, and, additionally, of the quality of child-caregiver relationship. Current quality of care experienced in the institution, operationalized in terms of the absence (vs. presence) of a preferred caregiver, predicted indiscriminate social behavior over and above prenatal and family risk conditions that preceded the child's institutionalization.

  16. Characterization of interference thin films grown on stainless steel surface by alternate pulse current in a sulphochromic solution

    Directory of Open Access Journals (Sweden)

    Rosa Maria Rabelo Junqueira

    2008-12-01

    Full Text Available The aim of this work was to characterize thin interference films grown on the surface of AISI 304 stainless steel for decorative purposes. Films were grown in a sulphochromic solution at room temperature by an alternating pulse current method. The morphology and chemical state of the elements in the films were investigated by field emission scanning electron microscopy (FESEM, atomic force microscopy (AFM, glow discharge optical emission spectrometry (GDOES, and infrared Fourier transform spectroscopy (FTIR. Depth-sensing indentation (DSI experiments and wear abrasion tests were employed to assess the mechanical resistance of the films. The coloration process resulted in porous thin films which increased the surface roughness of the substrate. The interference films mainly consisted of hydrated chromium oxide containing iron. Increasing film thickness produced different colors and affected the mechanical properties of the coating-substrate system. Thicker films, such as those producing gold and green colors, were softer but more abrasion resistant.

  17. Experimental design to measure the anchoring energy on substrate surface by using the alternating-current bridge

    International Nuclear Information System (INIS)

    Hao Hui-Ming; Liu Yao-Yao; Zhang Ping; Zhu Ji-Liang; Ye Wen-Jiang; Cai Ming-Lei; Wang Xiao-Yan

    2017-01-01

    The anchoring property of the substrate surface of liquid crystal cells plays an important role in display and nondisplay fields. This property directly affects the deformation of liquid crystal molecules to change the phase difference through liquid crystal cells. In this paper, a test method based on the alternating-current bridge is proposed to determine the capacitance of liquid crystal cells and thus measure the anchoring energy of the substrate surface. The anchoring energy can be obtained by comparing the capacitance–voltage curves of twisted nematic liquid crystal cells with different anchoring properties in experimental and theoretical results simulated on the basis of Frank elastic theory. Compared with the other methods to determine the anchoring energy, our proposed method requires a simple treatment of liquid crystal cells and allows easy and high-accuracy measurements, thereby expanding the test ideas on the performance parameters of liquid crystal devices. (paper)

  18. Research of the use of silver nanowires as a current spreading layer on vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Guo, Xia; Shi, Lei; Li, Chong; Dong, Jian; Liu, Bai; Hu, Shuai; He, Yan

    2016-11-01

    Silver nanowire (AgNW) film was proposed to apply on the surface of the vertical-cavity surface-emitting lasers (VCSELs) with large aperture in order to obtain a uniform current distribution in the active region and a better optical beam quality. Optimization of the AgNW film was carried out with the sheet resistance of 28.4 Ω/sq and the optical transmission of 94.8% at 850 nm. The performance of VCSELs with and without AgNW film was studied. When the AgNW film was applied to the surface of VCSELs, due to its better current spreading effect, the maximum output optical power increased from 23.4 mW to 24.4 mW, the lasing wavelength redshift decreased from 0.085 nm/mA to 0.077 nm/mA, the differential resistance decreased from 23.95 Ω to 21.13 Ω, and the far field pattern at 50 mA decreased from 21.6° to 19.2°. At the same time, the near field test results showed that the light in the aperture was more uniform, and the far field exhibited a better single peak characteristic. Various results showed that VCSELs with AgNW on the surface showed better beam quality. Project supported by the National Natural Science Foundation of China (Grant Nos. 61335004 and 61505003), the National High Technology Research and Development Program of China (Grant No. 2015AA017101), and the National Key Research and Development of China (Grant No. 2016YFB0400603).

  19. Verification of Forecast Weather Surface Variables over Vietnam Using the National Numerical Weather Prediction System

    Directory of Open Access Journals (Sweden)

    Tien Du Duc

    2016-01-01

    Full Text Available The national numerical weather prediction system of Vietnam is presented and evaluated. The system is based on three main models, namely, the Japanese Global Spectral Model, the US Global Forecast System, and the US Weather Research and Forecasting (WRF model. The global forecast products have been received at 0.25- and 0.5-degree horizontal resolution, respectively, and the WRF model has been run locally with 16 km horizontal resolution at the National Center for Hydro-Meteorological Forecasting using lateral conditions from GSM and GFS. The model performance is evaluated by comparing model output against observations of precipitation, wind speed, and temperature at 168 weather stations, with daily data from 2010 to 2014. In general, the global models provide more accurate forecasts than the regional models, probably due to the low horizontal resolution in the regional model. Also, the model performance is poorer for stations with altitudes greater than 500 meters above sea level (masl. For tropical cyclone performance validations, the maximum wind surface forecast from global and regional models is also verified against the best track of Joint Typhoon Warning Center. Finally, the model forecast skill during a recent extreme rain event in northeast Vietnam is evaluated.

  20. Prediction for human intelligence using morphometric characteristics of cortical surface: partial least square analysis.

    Science.gov (United States)

    Yang, J-J; Yoon, U; Yun, H J; Im, K; Choi, Y Y; Lee, K H; Park, H; Hough, M G; Lee, J-M

    2013-08-29

    A number of imaging studies have reported neuroanatomical correlates of human intelligence with various morphological characteristics of the cerebral cortex. However, it is not yet clear whether these morphological properties of the cerebral cortex account for human intelligence. We assumed that the complex structure of the cerebral cortex could be explained effectively considering cortical thickness, surface area, sulcal depth and absolute mean curvature together. In 78 young healthy adults (age range: 17-27, male/female: 39/39), we used the full-scale intelligence quotient (FSIQ) and the cortical measurements calculated in native space from each subject to determine how much combining various cortical measures explained human intelligence. Since each cortical measure is thought to be not independent but highly inter-related, we applied partial least square (PLS) regression, which is one of the most promising multivariate analysis approaches, to overcome multicollinearity among cortical measures. Our results showed that 30% of FSIQ was explained by the first latent variable extracted from PLS regression analysis. Although it is difficult to relate the first derived latent variable with specific anatomy, we found that cortical thickness measures had a substantial impact on the PLS model supporting the most significant factor accounting for FSIQ. Our results presented here strongly suggest that the new predictor combining different morphometric properties of complex cortical structure is well suited for predicting human intelligence. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. Variability of Surface pollutants and aerosol concentration over Abu Dhabi, UAE - sources, transport and current levels

    Science.gov (United States)

    Phanikumar, Devulapalli V.; Basha, Ghouse; Ouarda, Taha B. M. J.

    2015-04-01

    pollutants are in contrast with the diurnal pattern of wind speed as evident from the previous observations. Wind rose diagram of pollutants reveal that the dominant source directions are scattered from northwesterly to southwesterly. Our results (2011-13) are compared with earlier observations from the same region (2007-08) and no alarming differences were observed in the pollutant levels. Our observations are discussed in the light of current understanding of pollutants sources over this region.

  2. Bioavailability of elemental iron powders to rats is less than bakery-grade ferrous sulfate and predicted by iron solubility and particle surface area.

    Science.gov (United States)

    Swain, James H; Newman, Samuel M; Hunt, Janet R

    2003-11-01

    Foods are fortified with elemental forms of iron to reduce iron deficiency. However, the nutritional efficacy of current, commercially produced elemental iron powders has not been verified. We determined the bioavailability of six commercial elemental iron powders and examined how physicochemistry influences bioavailability. Relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method, treating iron-deficient rats with repletion diets fortified with graded quantities of iron powders, bakery-grade ferrous sulfate or no added iron. Iron powders were assessed physicochemically by measuring iron solubility in hydrochloric acid at pH 1.0 and 1.7, surface area by nitrogen gas adsorption and surface microstructure by electron microscopy. Bioavailability from the iron powders, based on absolute iron intake, was significantly less than from FeSO4 (100%; P Electrolytic (54%; A-131, U.S.) > Electrolytic (46%; Electrolytic Iron, India) > H-Reduced (42%; AC-325, U.S.) > Reduced (24%; ATOMET 95SP, Canada) > CO-Reduced (21%; RSI-325, Sweden). Solubility testing of the iron powders resulted in different relative rankings and better RBV predictability with increasing time at pH 1.7 (R2 = 0.65 at 150 min). The prediction was improved with less time and lower pH (R2 = 0.82, pH 1.0 at 30 min). Surface area, ranging from 90 to 370 m2/kg, was also highly predictive of RBV (R2 = 0.80). Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to three times among different commercial forms. Solubility at pH 1.0 and surface area were predictive of iron bioavailability in rats.

  3. Prediction of Carbohydrate Binding Sites on Protein Surfaces with 3-Dimensional Probability Density Distributions of Interacting Atoms

    Science.gov (United States)

    Tsai, Keng-Chang; Jian, Jhih-Wei; Yang, Ei-Wen; Hsu, Po-Chiang; Peng, Hung-Pin; Chen, Ching-Tai; Chen, Jun-Bo; Chang, Jeng-Yih; Hsu, Wen-Lian; Yang, An-Suei

    2012-01-01

    Non-covalent protein-carbohydrate interactions mediate molecular targeting in many biological processes. Prediction of non-covalent carbohydrate binding sites on protein surfaces not only provides insights into the functions of the query proteins; information on key carbohydrate-binding residues could suggest site-directed mutagenesis experiments, design therapeutics targeting carbohydrate-binding proteins, and provide guidance in engineering protein-carbohydrate interactions. In this work, we show that non-covalent carbohydrate binding sites on protein surfaces can be predicted with relatively high accuracy when the query protein structures are known. The prediction capabilities were based on a novel encoding scheme of the three-dimensional probability density maps describing the distributions of 36 non-covalent interacting atom types around protein surfaces. One machine learning model was trained for each of the 30 protein atom types. The machine learning algorithms predicted tentative carbohydrate binding sites on query proteins by recognizing the characteristic interacting atom distribution patterns specific for carbohydrate binding sites from known protein structures. The prediction results for all protein atom types were integrated into surface patches as tentative carbohydrate binding sites based on normalized prediction confidence level. The prediction capabilities of the predictors were benchmarked by a 10-fold cross validation on 497 non-redundant proteins with known carbohydrate binding sites. The predictors were further tested on an independent test set with 108 proteins. The residue-based Matthews correlation coefficient (MCC) for the independent test was 0.45, with prediction precision and sensitivity (or recall) of 0.45 and 0.49 respectively. In addition, 111 unbound carbohydrate-binding protein structures for which the structures were determined in the absence of the carbohydrate ligands were predicted with the trained predictors. The overall

  4. Surface potential based modeling of charge, current, and capacitances in DGTFET including mobile channel charge and ambipolar behaviour

    Science.gov (United States)

    Jain, Prateek; Yadav, Chandan; Agarwal, Amit; Chauhan, Yogesh Singh

    2017-08-01

    We present a surface potential based analytical model for double gate tunnel field effect transistor (DGTFET) for the current, terminal charges, and terminal capacitances. The model accounts for the effect of the mobile charge in the channel and captures the device physics in depletion as well as in the strong inversion regime. The narrowing of the tunnel barrier in the presence of mobile charges in the channel is incorporated via modeling of the inverse decay length, which is constant under channel depletion condition and bias dependent under inversion condition. To capture the ambipolar current behavior in the model, tunneling at the drain junction is also included. The proposed model is validated against TCAD simulation data and it shows close match with the simulation data.

  5. Artificial neural network and response surface methodology modeling in mass transfer parameters predictions during osmotic dehydration of Carica papaya L.

    Directory of Open Access Journals (Sweden)

    J. Prakash Maran

    2013-09-01

    Full Text Available In this study, a comparative approach was made between artificial neural network (ANN and response surface methodology (RSM to predict the mass transfer parameters of osmotic dehydration of papaya. The effects of process variables such as temperature, osmotic solution concentration and agitation speed on water loss, weight reduction, and solid gain during osmotic dehydration were investigated using a three-level three-factor Box-Behnken experimental design. Same design was utilized to train a feed-forward multilayered perceptron (MLP ANN with back-propagation algorithm. The predictive capabilities of the two methodologies were compared in terms of root mean square error (RMSE, mean absolute error (MAE, standard error of prediction (SEP, model predictive error (MPE, chi square statistic (χ2, and coefficient of determination (R2 based on the validation data set. The results showed that properly trained ANN model is found to be more accurate in prediction as compared to RSM model.

  6. Damage and annealing recovery of boron-implanted ultra-shallow junction: The correlation between beam current and surface configuration

    Science.gov (United States)

    Chang, Feng-Ming; Wu, Zong-Zhe; Lin, Yen-Fu; Kao, Li-Chi; Wu, Cheng-Ta; JangJian, Shiu-Ko; Chen, Yuan-Nian; Lo, Kuang Yao

    2018-03-01

    The condition of the beam current in the implantation process is a key issue in the damage rate and structural evolution in the sequent annealing process, especially for ultra-shallow layers. In this work, we develop a compensative optical method combined with UV Raman, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near edge spectroscopy (XANES) to inspect the influence of the beam current in the implantation process. The optima condition of the beam current in the implantation process is determined by higher effective Si-B bond portion in UV Raman spectra and less the peak of B-B bond in XPS spectra which is caused by B cluster defects. Results of XANES indicate that the B oxide layer is formed on the surface of the ultra-shallow junction. The defects in the ultra-shallow junction after annealing are analyzed by novel optical analyses, which cannot be inspected by a traditional thermal wave and resistance measurement. This work exhibits the structural variation of the ultra-shallow junction via a variant beam current and provides a valuable metrology in examining the chemical states and the effective activation in the implantation technology.

  7. Towards surface analysis on diabetic feet soles to predict ulcerations using photometric stereo

    Science.gov (United States)

    Liu, Chanjuan; van der Heijden, Ferdi; van Netten, Jaap J.

    2012-03-01

    Diabetic foot ulceration is a major complication for patients with diabetes mellitus. Approximately 15% to 25% of patients with Type I and Type II diabetes eventually develop feet ulcers. If not adequately treated, these ulcers may lead to foot infection, and ultimately to total (or partial) lower extremity amputation, which means a great loss in health-related quality of life. The incidence of foot ulcers may be prevented by early identification and subsequent treatment of pre-signs of ulceration, such as callus formation, redness, fissures, and blisters. Therefore, frequent examination of the feet is necessary, preferably on a daily basis. However, self-examination is difficult or impossible due to consequences of the diabetes. Moreover, frequent examination by health care professionals is costly and not feasible. The objective of our project is to develop an intelligent telemedicine monitoring system that can be deployed at the patients' home environment for frequent examination of patients feet, to timely detect pre-signs of ulceration. The current paper reports the preliminary results of an implementation of a photometric stereo imaging system to detect 3D geometric abnormalities of the skin surfaces of foot soles. Using a flexible experimental setup, the system parameters such as number and positions of the illuminators have been selected so as to optimize the performance with respect to reconstructed surface. The system has been applied to a dummy foot sole. Finally, the curvature on the resulting 3D topography of the foot sole is implemented to show the feasibility of detecting the pre-signs of ulceration using photometric stereo imaging. The obtained results indicate clinical potential of this technology for detecting the pre-signs of ulceration on diabetic feet soles.

  8. TH-CD-207A-05: Lung Surface Deformation Vector Fields Prediction by Monitoring Respiratory Surrogate Signals

    International Nuclear Information System (INIS)

    Nasehi Tehrani, J; Wang, J; McEwan, A

    2016-01-01

    Purpose: In this study, we developed and evaluated a method for predicting lung surface deformation vector fields (SDVFs) based on surrogate signals such as chest and abdomen motion at selected locations and spirometry measurements. Methods: A Patient-specific 3D triangular surface mesh of the lung region at end-expiration (EE) phase was obtained by threshold-based segmentation method. For each patient, a spirometer recorded the flow volume changes of the lungs; and 192 selected points at a regular spacing of 2cm X 2cm matrix points over a total area of 34cm X 24cm on the surface of chest and abdomen was used to detect chest wall motions. Preprocessing techniques such as QR factorization with column pivoting (QRCP) were employed to remove redundant observations of the chest and abdominal area. To create a statistical model between the lung surface and the corresponding surrogate signals, we developed a predictive model based on canonical ridge regression (CRR). Two unique weighting vectors were selected for each vertex on the surface of the lung, and they were optimized during the training process using the all other phases of 4D-CT except the end-inspiration (EI) phase. These parameters were employed to predict the vertices locations of a testing data set, which was the EI phase of 4D-CT. Results: For ten lung cancer patients, the deformation vector field of each vertex of lung surface mesh was estimated from the external motion at selected positions on the chest wall surface plus spirometry measurements. The average estimation of 98th percentile of error was less than 1 mm (AP= 0.85, RL= 0.61, and SI= 0.82). Conclusion: The developed predictive model provides a non-invasive approach to derive lung boundary condition. Together with personalized biomechanical respiration modelling, the proposed model can be used to derive the lung tumor motion during radiation therapy accurately from non-invasive measurements.

  9. TH-CD-207A-05: Lung Surface Deformation Vector Fields Prediction by Monitoring Respiratory Surrogate Signals

    Energy Technology Data Exchange (ETDEWEB)

    Nasehi Tehrani, J; Wang, J [UT Southwestern Medical Center, Dallas, TX (United States); McEwan, A [The University of Sydney, Sydney, New South Wales (Australia)

    2016-06-15

    Purpose: In this study, we developed and evaluated a method for predicting lung surface deformation vector fields (SDVFs) based on surrogate signals such as chest and abdomen motion at selected locations and spirometry measurements. Methods: A Patient-specific 3D triangular surface mesh of the lung region at end-expiration (EE) phase was obtained by threshold-based segmentation method. For each patient, a spirometer recorded the flow volume changes of the lungs; and 192 selected points at a regular spacing of 2cm X 2cm matrix points over a total area of 34cm X 24cm on the surface of chest and abdomen was used to detect chest wall motions. Preprocessing techniques such as QR factorization with column pivoting (QRCP) were employed to remove redundant observations of the chest and abdominal area. To create a statistical model between the lung surface and the corresponding surrogate signals, we developed a predictive model based on canonical ridge regression (CRR). Two unique weighting vectors were selected for each vertex on the surface of the lung, and they were optimized during the training process using the all other phases of 4D-CT except the end-inspiration (EI) phase. These parameters were employed to predict the vertices locations of a testing data set, which was the EI phase of 4D-CT. Results: For ten lung cancer patients, the deformation vector field of each vertex of lung surface mesh was estimated from the external motion at selected positions on the chest wall surface plus spirometry measurements. The average estimation of 98th percentile of error was less than 1 mm (AP= 0.85, RL= 0.61, and SI= 0.82). Conclusion: The developed predictive model provides a non-invasive approach to derive lung boundary condition. Together with personalized biomechanical respiration modelling, the proposed model can be used to derive the lung tumor motion during radiation therapy accurately from non-invasive measurements.

  10. Magnetization switching of a metallic nanomagnet via current-induced surface spin-polarization of an underlying topological insulator

    International Nuclear Information System (INIS)

    Roy, Urmimala; Dey, Rik; Pramanik, Tanmoy; Ghosh, Bahniman; Register, Leonard F.; Banerjee, Sanjay K.

    2015-01-01

    We consider a thermally stable, metallic nanoscale ferromagnet (FM) subject to spin-polarized current injection and exchange coupling from the spin-helically locked surface states of a topological insulator (TI) to evaluate possible non-volatile memory applications. We consider parallel transport in the TI and the metallic FM, and focus on the efficiency of magnetization switching as a function of transport between the TI and the FM. Transport is modeled as diffusive in the TI beneath the FM, consistent with the mobility in the TI at room temperature, and in the FM, which essentially serves as a constant potential region albeit spin-dependent except in the low conductivity, diffusive limit. Thus, it can be captured by drift-diffusion simulation, which allows for ready interpretation of the results. We calculate switching time and energy consumed per write operation using self-consistent transport, spin-transfer-torque (STT), and magnetization dynamics calculations. Calculated switching energies and times compare favorably to conventional spin-torque memory schemes for substantial interlayer conductivity. Nevertheless, we find that shunting of current from the TI to a metallic nanomagnet can substantially limit efficiency. Exacerbating the problem, STT from the TI effectively increases the TI resistivity. We show that for optimum performance, the sheet resistivity of the FM layer should be comparable to or larger than that of the TI surface layer. Thus, the effective conductivity of the FM layer becomes a critical design consideration for TI-based non-volatile memory

  11. On the Feasibility of Eddy Current Characterization of the Near-Surface Residual Stress Distribution in Nickel-Base Superalloys

    International Nuclear Information System (INIS)

    Blodgett, Mark P.; Nagy, Peter B.

    2004-01-01

    In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in shot-peened specimens. This technique is based on the so-called electroelastic effect, i.e., the stress-dependence of the electrical conductivity. Unfortunately, the relatively small (∼1%) change in electrical conductivity caused by the presence of compressive residual stresses is often distorted, or even completely overshadowed, by the accompanying conductivity loss caused by cold work and surface roughness effects. Recently, it was observed that, in contrast with most other materials, shot-peened Waspaloy and IN100 specimens exhibit an apparent increase in electrical conductivity at increasing inspection frequencies. This observation by itself indicates that in these materials the measured conductivity change is probably dominated by residual stress effects, since both surface roughness and increased dislocation density are known to decrease rather than increase the conductivity and the presence of crystallographic texture does not affect the electrical conductivity of these materials, which crystallize in cubic symmetry. Our preliminary experiments indicate that probably there exists a unique 'window of opportunity' for eddy current NDE in nickel-base superalloys. We identified five major effects that contribute to this fortunate constellation of material properties, which will be reviewed in this presentation

  12. Prediction of protein retention times in hydrophobic interaction chromatography by robust statistical characterization of their atomic-level surface properties.

    Science.gov (United States)

    Hanke, Alexander T; Klijn, Marieke E; Verhaert, Peter D E M; van der Wielen, Luuk A M; Ottens, Marcel; Eppink, Michel H M; van de Sandt, Emile J A X

    2016-03-01

    The correlation between the dimensionless retention times (DRT) of proteins in hydrophobic interaction chromatography (HIC) and their surface properties were investigated. A ternary atomic-level hydrophobicity scale was used to calculate the distribution of local average hydrophobicity across the proteins surfaces. These distributions were characterized by robust descriptive statistics to reduce their sensitivity to small changes in the three-dimensional structure. The applicability of these statistics for the prediction of protein retention behaviour was looked into. A linear combination of robust statistics describing the central tendency, heterogeneity and frequency of highly hydrophobic clusters was found to have a good predictive capability (R2  = 0.78), when combined a factor to account for protein size differences. The achieved error of prediction was 35% lower than for a similar model based on a description of the protein surface on an amino acid level. This indicates that a robust and mathematically simple model based on an atomic description of the protein surface can be used for the prediction of the retention behaviour of conformationally stable globular proteins with a well determined 3D structure in HIC. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:372-381, 2016. © 2016 American Institute of Chemical Engineers.

  13. Predicting surface fuel models and fuel metrics using lidar and CIR imagery in a dense mixed conifer forest

    Science.gov (United States)

    Marek K. Jakubowksi; Qinghua Guo; Brandon Collins; Scott Stephens; Maggi. Kelly

    2013-01-01

    We compared the ability of several classification and regression algorithms to predict forest stand structure metrics and standard surface fuel models. Our study area spans a dense, topographically complex Sierra Nevada mixed-conifer forest. We used clustering, regression trees, and support vector machine algorithms to analyze high density (average 9 pulses/m

  14. Prediction of Spiral Patterns on the Surface of Asteroid 101955 Bennu

    Science.gov (United States)

    Kreslavsky, M. A.

    2017-12-01

    Asteroid 101955 Bennu, the target of OSIRIS-REx space mission, is known to have a "walnut" shape: close to an axially symmetric oblate shape with a sharp equatorial ridge (Nolan M. C., et al., 2013, Icarus 226, 629-640, doi:10.1016/j.icarus.2013.05.028). Such a shape is usual among quickly spinning small asteroids; it is thought to be formed due to surficial transport of asteroid material toward equator under a combination of the gravitational and centrifugal forces, in other words, downhill with respect to the geopotential (e.g., Scheeres, D. J., et al., 2006, Science 314, 1280-1283, doi:10.1126/science.1133599). This is likely to occur, when a rubble-pile asteroid is spun up by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. The Rossby number Ro associated with the frictionless downslope movement is scaled as (T/2π)(g sinθ/L)1/2, where T the spin period, g is a characteristic value of the effective gravity (the geopotential gradient), θ is the characteristic surface slope with respect to the geopotential, and L is the characteristic scale length of the slope. Typical values for Bennu, g 6×10-5 m s-2, θ 30° (Scheeres, D.J., et al., 2016, Icarus 276, 116-140, doi:10.1016/j.icarus.2016.04.013), and L 100 m, a part of Bennu radius, yields Ro 1.3, which means that the Coriolis force play a significant role in the downslope movement dynamics. On this basis, it is reasonable to predict that the traces left by material sliding toward equator on Bennu would form spiral patterns. Hopefully, OSIRIS-REx mission will check the prediction soon. I modeled trajectories of rolling boulders, bouncing boulders, and sliding masses assuming different friction models. For these calculations I used an idealized axially symmetric Bennu shape and semianalytical calculation of gravitational potential. I also repeated the calculation for a set of higher spin rates that may be relevant to the geologically recent past. Although the trajectory form itself is insufficient to

  15. Prediction of lake surface temperature using the air2water model: guidelines, challenges, and future perspectives

    Directory of Open Access Journals (Sweden)

    Sebastiano Piccolroaz

    2016-04-01

    Full Text Available Water temperature plays a primary role in controlling a wide range of physical, geochemical and ecological processes in lakes, with considerable influences on lake water quality and ecosystem functioning. Being able to reliably predict water temperature is therefore a desired goal, which stimulated the development of models of different type and complexity, ranging from simple regression-based models to more sophisticated process-based numerical models. However, both types of models suffer of some limitations: the first are not able to address some fundamental physical processes as e.g., thermal stratification, while the latter generally require a large amount of data in input, which are not always available. In this work, lake surface temperature is simulated by means of air2water, a hybrid physically-based/statistical model, which is able to provide a robust, predictive understanding of LST dynamics knowing air temperature only. This model showed performances that are comparable with those obtained by using process based models (a root mean square error on the order of 1°C, at daily scale, while retaining the simplicity and parsimony of regression-based models, thus making it a good candidate for long-term applications.The aim of the present work is to provide the reader with useful and practical guidelines for proper use of the air2water model and for critical analysis of results. Two case studies have been selected for the analysis: Lake Superior and Lake Erie. These are clear and emblematic examples of a deep and a shallow temperate lake characterized by markedly different thermal responses to external forcing, thus are ideal for making the results of the analysis the most general and comprehensive. Particular attention is paid to assessing the influence of missing data on model performance, and to evaluating when an observed time series is sufficiently informative for proper model calibration or, conversely, data are too scarce thus

  16. Preoperative prediction of histopathological outcome in basal cell carcinoma: flat surface and multiple small erosions predict superficial basal cell carcinoma in lighter skin types.

    Science.gov (United States)

    Ahnlide, I; Zalaudek, I; Nilsson, F; Bjellerup, M; Nielsen, K

    2016-10-01

    Prediction of the histopathological subtype of basal cell carcinoma (BCC) is important for tailoring optimal treatment, especially in patients with suspected superficial BCC (sBCC). To assess the accuracy of the preoperative prediction of subtypes of BCC in clinical practice, to evaluate whether dermoscopic examination enhances accuracy and to find dermoscopic criteria for discriminating sBCC from other subtypes. The main presurgical diagnosis was compared with the histopathological, postoperative diagnosis of routinely excised skin tumours in a predominantly fair-skinned patient cohort of northern Europe during a study period of 3 years (2011-13). The study period was split in two: during period 1, dermoscopy was optional (850 cases with a pre- or postoperative diagnosis of BCC), while during period 2 (after an educational dermoscopic update) dermoscopy was mandatory (651 cases). A classification tree based on clinical and dermoscopic features for prediction of sBCC was applied. For a total of 3544 excised skin tumours, the sensitivity for the diagnosis of BCC (any subtype) was 93·3%, specificity 91·8%, and the positive predictive value (PPV) 89·0%. The diagnostic accuracy as well as the PPV and the positive likelihood ratio for sBCC were significantly higher when dermoscopy was mandatory. A flat surface and multiple small erosions predicted sBCC. The study shows a high accuracy for an overall diagnosis of BCC and increased accuracy in prediction of sBCC for the period when dermoscopy was applied in all cases. The most discriminating findings for sBCC, based on clinical and dermoscopic features in this fair-skinned population, were a flat surface and multiple small erosions. © 2016 British Association of Dermatologists.

  17. CALYPSO: a new HF RADAR network to monitor sea surface currents in the Malta-Sicily channel (Mediterranean sea)

    Science.gov (United States)

    Cosoli, S.; Ciraolo, G.; Drago, A.; Capodici, F.; Maltese, A.; Gauci, A.; Galea, A.; Azzopardi, J.; Buscaino, G.; Raffa, F.; Mazzola, S.; Sinatra, R.

    2016-12-01

    Located in one of the main shipping lanes in the Mediterranean Sea, and in a strategic region for oil extraction platforms, the Malta-Sicily channel is exposed to significant oil spill risks. Shipping and extraction activities constitute a major threat for marine areas of relevant ecological value in the area, and impacts of oil spills on the local ecosystems and the economic activities, including tourism and fisheries, can be dramatic. Damages would be even more devastating for the Maltese archipelago, where marine resources represent important economic assets. Additionally, North Africa coastal areas are also under threat, due to their proximity to the Malta-Sicily Channel. Prevention and mitigation measures, together with rapid-response and decision-making in case of emergency situations, are fundamental steps that help accomplishing the tasks of minimizing risks and reducing impacts to the various compartments. Thanks to state-of-art technology for the monitoring of sea-surface currents in real-time under all sea-state conditions, the CALYPSO network of High-Frequency Radars represents an essential and invaluable tool for the specific purpose. HF radars technology provide a unique tool to track surface currents in near-real time, and as such the dispersion of pollutants can be monitored and forecasted and their origin backtracked, for instance through data assimilation into ocean circulation models or through short-term data-driven statistical forecasts of ocean currents. The network is constituted of four SeaSonde systems that work in the 13.5MHz frequency band. The network is operative since August 2012 and has been extensively validated using a variety of independent platforms and devices, including current meter data and drifting buoys. The latter provided clear evidences of the reliability of the collected data as for tracking the drifting objects. Additionally, data have provided a new insight into the oceanographic characteristics of the region

  18. Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2008-12-01

    Full Text Available We develop two related models of magnetosphere-ionosphere coupling in the jovian system by combining previous models defined at ionospheric heights with magnetospheric magnetic models that allow system parameters to be extended appropriately into the magnetosphere. The key feature of the combined models is thus that they allow direct connection to be made between observations in the magnetosphere, particularly of the azimuthal field produced by the magnetosphere-ionosphere coupling currents and the plasma angular velocity, and the auroral response in the ionosphere. The two models are intended to reflect typical steady-state sub-corotation conditions in the jovian magnetosphere, and transient super-corotation produced by sudden major solar wind-induced compressions, respectively. The key simplification of the models is that of axi-symmetry of the field, flow, and currents about the magnetic axis, limiting their validity to radial distances within ~30 RJ of the planet, though the magnetic axis is appropriately tilted relative to the planetary spin axis and rotates with the planet. The first exploration of the jovian polar magnetosphere is planned to be undertaken in 2016–2017 during the NASA New Frontiers Juno mission, with observations of the polar field, plasma, and UV emissions as a major goal. Evaluation of the models along Juno planning orbits thus produces predictive results that may aid in science mission planning. It is shown in particular that the low-altitude near-periapsis polar passes will generally occur underneath the corresponding auroral acceleration regions, thus allowing brief examination of the auroral primaries over intervals of ~1–3 min for the main oval and ~10 s for narrower polar arc structures, while the "lagging" field deflections produced by the auroral current systems on these passes will be ~0.1°, associated with azimuthal fields above the ionosphere of a few hundred nT.

  19. Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2008-12-01

    Full Text Available We develop two related models of magnetosphere-ionosphere coupling in the jovian system by combining previous models defined at ionospheric heights with magnetospheric magnetic models that allow system parameters to be extended appropriately into the magnetosphere. The key feature of the combined models is thus that they allow direct connection to be made between observations in the magnetosphere, particularly of the azimuthal field produced by the magnetosphere-ionosphere coupling currents and the plasma angular velocity, and the auroral response in the ionosphere. The two models are intended to reflect typical steady-state sub-corotation conditions in the jovian magnetosphere, and transient super-corotation produced by sudden major solar wind-induced compressions, respectively. The key simplification of the models is that of axi-symmetry of the field, flow, and currents about the magnetic axis, limiting their validity to radial distances within ~30 RJ of the planet, though the magnetic axis is appropriately tilted relative to the planetary spin axis and rotates with the planet. The first exploration of the jovian polar magnetosphere is planned to be undertaken in 2016–2017 during the NASA New Frontiers Juno mission, with observations of the polar field, plasma, and UV emissions as a major goal. Evaluation of the models along Juno planning orbits thus produces predictive results that may aid in science mission planning. It is shown in particular that the low-altitude near-periapsis polar passes will generally occur underneath the corresponding auroral acceleration regions, thus allowing brief examination of the auroral primaries over intervals of ~1–3 min for the main oval and ~10 s for narrower polar arc structures, while the "lagging" field deflections produced by the auroral current systems on these passes will be ~0.1°, associated with azimuthal fields above the ionosphere of a few hundred nT.

  20. Multi-Annual Climate Predictions for Fisheries: An Assessment of Skill of Sea Surface Temperature Forecasts for Large Marine Ecosystems

    Directory of Open Access Journals (Sweden)

    Desiree Tommasi

    2017-06-01

    Full Text Available Decisions made by fishers and fisheries managers are informed by climate and fisheries observations that now often span more than 50 years. Multi-annual climate forecasts could further inform such decisions if they were skillful in predicting future conditions relative to the 50-year scope of past variability. We demonstrate that an existing multi-annual prediction system skillfully forecasts the probability of next year, the next 1–3 years, and the next 1–10 years being warmer or cooler than the 50-year average at the surface in coastal ecosystems. Probabilistic forecasts of upper and lower seas surface temperature (SST terciles over the next 3 or 10 years from the GFDL CM 2.1 10-member ensemble global prediction system showed significant improvements in skill over the use of a 50-year climatology for most Large Marine Ecosystems (LMEs in the North Atlantic, the western Pacific, and Indian oceans. Through a comparison of the forecast skill of initialized and uninitialized hindcasts, we demonstrate that this skill is largely due to the predictable signature of radiative forcing changes over the 50-year timescale rather than prediction of evolving modes of climate variability. North Atlantic LMEs stood out as the only coastal regions where initialization significantly contributed to SST prediction skill at the 1 to 10 year scale.

  1. Examining the Impacts of High-Resolution Land Surface Initialization on Model Predictions of Convection in the Southeastern U.S.

    Science.gov (United States)

    Case, Jonathan L.; Kumar, Sujay V.; Santos, Pablo; Medlin, Jeffrey M.; Jedlovec, Gary J.

    2009-01-01

    One of the most challenging weather forecast problems in the southeastern U.S. is daily summertime pulse convection. During the summer, atmospheric flow and forcing are generally weak in this region; thus, convection typically initiates in response to local forcing along sea/lake breezes, and other discontinuities often related to horizontal gradients in surface heating rates. Numerical simulations of pulse convection usually have low skill, even in local predictions at high resolution, due to the inherent chaotic nature of these precipitation systems. Forecast errors can arise from assumptions within physics parameterizations, model resolution limitations, as well as uncertainties in both the initial state of the atmosphere and land surface variables such as soil moisture and temperature. For this study, it is hypothesized that high-resolution, consistent representations of surface properties such as soil moisture and temperature, ground fluxes, and vegetation are necessary to better simulate the interactions between the land surface and atmosphere, and ultimately improve predictions of local circulations and summertime pulse convection. The NASA Short-term Prediction Research and Transition (SPORT) Center has been conducting studies to examine the impacts of high-resolution land surface initialization data generated by offline simulations of the NASA Land Informatiot System (LIS) on subsequent numerical forecasts using the Weather Research and Forecasting (WRF) model (Case et al. 2008, to appear in the Journal of Hydrometeorology). Case et al. presents improvements to simulated sea breezes and surface verification statistics over Florida by initializing WRF with land surface variables from an offline LIS spin-up run, conducted on the exact WRF domain and resolution. The current project extends the previous work over Florida, focusing on selected case studies of typical pulse convection over the southeastern U.S., with an emphasis on improving local short-term WRF

  2. Developing equations to predict surface dose and therapeutic interval in bolused electron fields: A Monte Carlo Study

    Science.gov (United States)

    Jabbari, Nasrollah; Khalkhali, Hamid Reza

    2017-07-01

    In this research, we aim to investigate the influence of different materials, as a bolus, on the low-energy electron beam dose distributions and to develop equations for predicting surface dose based on bolus thickness, as well as the therapeutic interval based on surface dose. All the Monte Carlo (MC) calculations and measurements were conducted on a Siemens PRIMUS linac. Based on EGSnrc MC code, BEAMnrc system was used to model a Siemens linac and generate phase-space files for three electron beams (6, 8, and 10 MeV). The particles were transported from the phase-space files to the bolus materials and the simulated water phantom using DOSXYZnrc. Various materials with different thicknesses were examined as a bolus, and appropriate equations were determined for each material and electron beam. The comparison of percent depth dose (PDD) curves and beam profiles, using MC, with the measured data demonstrated that the calculated values properly matched with the measurements. The results indicated that the use of bolus materials with the density of higher than soft tissue can increase both surface dose and therapeutic interval simultaneously. This finding arises from the fact that the required bolus thickness for achieving the therapeutic surface dose decreases in the case of high-density materials. Two series of prediction equations were proposed for predicting the surface dose based on bolus thickness and the therapeutic interval based on surface dose. These equations are able to calculate properly the bolus thickness required for producing a therapeutic surface dose (above 90%) for any therapeutic interval.

  3. An analytical model for force prediction in ball nose micro milling of inclined surfaces

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2010-01-01

    Ball nose micro milling is a key process for the generation of free form surfaces and inclined surfaces often present in mould inserts for micro replication. This paper presents a new cutting force model for ball nose micro milling that is capable of taking into account the effect of the edge rad...... radius and the effect of the surface topography due to the previous milling passes. The model is completely analytical can be applied to ball end micro milling of slanted surfaces for any value of the surface inclination angle relative to the tool axis....

  4. Surface potential, charging and local current transport of individual Ge quantum dots grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Singha, R.K. [Department of Physics, Visva-Bharati, Santiniketan 731235 (India); Manna, S.; Bar, R.; Das, S. [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: physkr@phy.iitkgp.ernet.in [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India)

    2017-06-15

    Highlights: We have elaborately explained the individual Ge QD charging phenomena and current transport, which is very important to understand the Ge/Si nano devices. This paper will give a flavor to properly understand these phenomena linked together along with the photocurrent mechanism which is related to the Ge/Si valence band offset. • Both the CAFM and KPFM techniques point out the functionality of doping nature of the underneath Si substrate on the aforementioned characteristics of Ge QDs. • Analysis of the surface potential mapping using KPFM technique yields an approximate valence band offset measurement which is required to understand the intra-valence transition of holes for the realization of long wavelength infrared photodetector. • KPFM and CAFM can be utilized to explore the charging/discharging phenomena of dots and their composition variations. • Current-voltage (I–V) characteristics of the individual Ge QD strongly depends on the individual QD size. • Energy band diagrams for diamond tip and Ge QD shows the higher barrier for electrons and lower barrier for holes allowing the easy tunneling for holes to dominate the transport. - Abstract: It is fundamentally important to understand the nanoscale electronic properties of a single quantum dot (QD) contrary to an ensemble of QDs. Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (CAFM) are two important tools, which could be employed to probe surface potential, charging phenomena, and current transport mechanism of individual QD. We demonstrate the aforementioned characteristics of self-assembled Ge QDs, which was grown on Si substrates by solid source molecular beam epitaxy driven by the Stranski-Krastanov method. Study reveals that each Ge QD acts as charge storage node even at zero applied bias. The shape, size and density of QDs could be well probed by CAFM and KPFM, whereas QD facets could be better resolved by the conductive tip. The CAFM investigation

  5. Mechanics of the Separating Surface for a Two-Phase Co-current Flow in a Porous Medium

    DEFF Research Database (Denmark)

    Shapiro, Alexander A.

    2016-01-01

    A mechanical description of an unsteady two-phase co-current flow in a porous medium is developed based on the analysis of the geometry and motion of the surface separating the two phases. It is demonstrated that the flow should be considered as essentially three-dimensional, even if the phase...... velocities are co-directed, since the phase interface is on average inclined to the direction of the flow. Kinematics of the flow is described, distinguishing between the average velocities of the bulk phases and their velocity near the interface between them. Dynamics of the flow is analyzed by means...... of the extended Maxwell-Stefan formalism, as in our previous paper (Shapiro 2015). Force balances are formulated in the directions parallel and orthogonal to the flow. A complete system of the flow equations, generalizing the traditional Buckley–Leverett and Rappoport–Leas system, is derived. Sample computations...

  6. Evaluation and Prediction present of radionuclide for surface wipe sample in Emergency Related with Fukushima Nuclear Accident

    International Nuclear Information System (INIS)

    Zalina Laili; Muhamat Omar; Woo, Y.M.

    2011-01-01

    Surface wipe samples of aircraft and container from Japan that were exposed to radioactive dust fallout due to Fukushima nuclear accident has been analysed using gamma spectrometry systems. The samples were analysed to determine their contamination levels. The surface of aircraft and container might be exposed to short and long lived fission and activation products. Thus, good evaluations, as well as a reliable and reasonable judgment were needed in order to determine the presence of fission and activation products. A work procedure has been developed to evaluate and predict the presence of fission and activation products in surface wipe samples. Good references, skilled and experienced level in analysis, a well calibrated and validated detector system were the important factors in determining the presence of fission and activation products in surface wipe samples. (author)

  7. Protein-Protein Interaction Site Predictions with Three-Dimensional Probability Distributions of Interacting Atoms on Protein Surfaces

    Science.gov (United States)

    Chen, Ching-Tai; Peng, Hung-Pin; Jian, Jhih-Wei; Tsai, Keng-Chang; Chang, Jeng-Yih; Yang, Ei-Wen; Chen, Jun-Bo; Ho, Shinn-Ying; Hsu, Wen-Lian; Yang, An-Suei

    2012-01-01

    Protein-protein interactions are key to many biological processes. Computational methodologies devised to predict protein-protein interaction (PPI) sites on protein surfaces are important tools in providing insights into the biological functions of proteins and in developing therapeutics targeting the protein-protein interaction sites. One of the general features of PPI sites is that the core regions from the two interacting protein surfaces are complementary to each other, similar to the interior of proteins in packing density and in the physicochemical nature of the amino acid composition. In this work, we simulated the physicochemical complementarities by constructing three-dimensional probability density maps of non-covalent interacting atoms on the protein surfaces. The interacting probabilities were derived from the interior of known structures. Machine learning algorithms were applied to learn the characteristic patterns of the probability density maps specific to the PPI sites. The trained predictors for PPI sites were cross-validated with the training cases (consisting of 432 proteins) and were tested on an independent dataset (consisting of 142 proteins). The residue-based Matthews correlation coefficient for the independent test set was 0.423; the accuracy, precision, sensitivity, specificity were 0.753, 0.519, 0.677, and 0.779 respectively. The benchmark results indicate that the optimized machine learning models are among the best predictors in identifying PPI sites on protein surfaces. In particular, the PPI site prediction accuracy increases with increasing size of the PPI site and with increasing hydrophobicity in amino acid composition of the PPI interface; the core interface regions are more likely to be recognized with high prediction confidence. The results indicate that the physicochemical complementarity patterns on protein surfaces are important determinants in PPIs, and a substantial portion of the PPI sites can be predicted correctly with

  8. Prediction of hemorrhagic transformation in acute ischemic stroke using permeability surface of CT perfusion

    International Nuclear Information System (INIS)

    Xiong Bing; Chen Weijian; Fufengli

    2012-01-01

    Objective: To investigate the value of permeability surface (PS) in predicting hemorrhagic transformation (HT) in acute ischernic stroke (AIS) using CT perfusion (CTP). Methods: The study included 31 consecutive patients who presented symptoms suggestive of an AIS for 3-9 h. All patients underwent CT examination (noncontrast CT, CTP). HT was determined by follow-up CT images. According to presence of HT, the AIS was divided into HT group (PS HT , 11 patients) and non-HT group (PS No-HT , 20 patients). PS, cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) on both sides of brains were measured.The relative PS (rPS), relative CBF (rCBF), relative CBV (rCBV) and relative MTT(rMTT) were obtained by calculating the ratio of the values of bilateral regions. The rPS between PS HT and PS No-HT was compared with an exact Wilcoxon signed-rank test. The rCBF, rCBV, rMTT and the PS of the ischemic side between PS HT and PS No-HT were compared with independent-sample t test. Meanwhile, Spearman rank correlation analysis was conducted to analyze the relationship between the CTP parameters and HT. Results: The PS value of ischemic side was (1.61 ±0.77) ml · min -1 · 100 g -1 for the PS HT group,and the value was (0.91 ± 0.49) ml · min -1 · 100 g -1 for the PS No-HT group. For the PS HT group, rPS, rCBF, rCBV, rMTT were 2.76 ±0.78, 0.32 ±0.18, 0.66 ±0.31, 2.67 ±0.71, and for the PS No-HT group, rPS, rCBF, rCBV, rMTT were 1.35 ±0.19, 0.50±0.21, 0.91 ±0.28, 2.62 ± 1.31. Compared with PS No-HT ,PS HT had higher rPS and PS value,and there were significant statistical differences (U=0.000, t=3.070, P<0.01). But rCBF and rCBV values were lower in the PS HT group compared to the PS No-HT group, and there were significant statistical differences (t rCBF =2.343, t rCBV =2.210, P<0.05). There was no significant statistical difference in rMTT between the two groups (t=0.118, P>0.05). Significant positive correlations were detected between the r

  9. Adverse childhood experiences predict earlier age of drinking onset: results from a representative US sample of current or former drinkers.

    Science.gov (United States)

    Rothman, Emily F; Edwards, Erika M; Heeren, Timothy; Hingson, Ralph W

    2008-08-01

    Our goal was to determine whether adverse childhood experiences predicted the age at which drinking was initiated and drinking motives in a representative sample of current or former drinkers in the United States. In 2006, a probability sample of 3592 US current or former drinkers aged 18 to 39 were surveyed. Multinomial logistic regression examined whether each of 10 adverse childhood experiences was associated with earlier ages of drinking onset, controlling for demographics, parental alcohol use, parental attitudes toward drinking, and peers' drinking in adolescence. We also examined whether there was a graded relationship between the number of adverse childhood experiences and age of drinking onset and whether adverse childhood experiences were related to self-reported motives for drinking during the first year that respondents drank. Sixty-six percent of respondents reported >or=1 adverse childhood experiences, and 19% reported experiencing >or=4. The most commonly reported adverse childhood experiences were parental separation/divorce (41.3%), living with a household member who was a problem drinker (28.7%), mental illness of a household member (24.8%), and sexual abuse (19.1%). Of the 10 specific adverse childhood experiences assessed, 5 were significantly associated with initiating drinking at or=21 years of age) after adjustment for confounders, including physical abuse, sexual abuse, having a mentally ill household member, substance abuse in the home, and parental discord or divorce. Compared with those without adverse childhood experiences, respondents with adverse childhood experiences were substantially more likely to report that they drank to cope during the first year that they used alcohol. Results suggest that children with particular adverse childhood experiences may initiate drinking earlier than their peers and that they may be more likely to drink to cope with problems (rather than for pleasure or to be social).

  10. Analytical prediction of sub-surface thermal history in translucent tissue phantoms during plasmonic photo-thermotherapy (PPTT).

    Science.gov (United States)

    Dhar, Purbarun; Paul, Anup; Narasimhan, Arunn; Das, Sarit K

    2016-12-01

    Knowledge of thermal history and/or distribution in biological tissues during laser based hyperthermia is essential to achieve necrosis of tumour/carcinoma cells. A semi-analytical model to predict sub-surface thermal distribution in translucent, soft, tissue mimics has been proposed. The model can accurately predict the spatio-temporal temperature variations along depth and the anomalous thermal behaviour in such media, viz. occurrence of sub-surface temperature peaks. Based on optical and thermal properties, the augmented temperature and shift of the peak positions in case of gold nanostructure mediated tissue phantom hyperthermia can be predicted. Employing inverse approach, the absorption coefficient of nano-graphene infused tissue mimics is determined from the peak temperature and found to provide appreciably accurate predictions along depth. Furthermore, a simplistic, dimensionally consistent correlation to theoretically determine the position of the peak in such media is proposed and found to be consistent with experiments and computations. The model shows promise in predicting thermal distribution induced by lasers in tissues and deduction of therapeutic hyperthermia parameters, thereby assisting clinical procedures by providing a priori estimates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Prediction of Forest Canopy and Surface Fuels from Lidar and Satellite Time Series Data in a Bark Beetle-Affected Forest

    Directory of Open Access Journals (Sweden)

    Benjamin C. Bright

    2017-08-01

    Full Text Available Wildfire behavior depends on the type, quantity, and condition of fuels, and the effect that bark beetle outbreaks have on fuels is a topic of current research and debate. Remote sensing can provide estimates of fuels across landscapes, although few studies have estimated surface fuels from remote sensing data. Here we predicted and mapped field-measured canopy and surface fuels from light detection and ranging (lidar and Landsat time series explanatory variables via random forest (RF modeling across a coniferous montane forest in Colorado, USA, which was affected by mountain pine beetles (Dendroctonus ponderosae Hopkins approximately six years prior. We examined relationships between mapped fuels and the severity of tree mortality with correlation tests. RF models explained 59%, 48%, 35%, and 70% of the variation in available canopy fuel, canopy bulk density, canopy base height, and canopy height, respectively (percent root-mean-square error (%RMSE = 12–54%. Surface fuels were predicted less accurately, with models explaining 24%, 28%, 32%, and 30% of the variation in litter and duff, 1 to 100-h, 1000-h, and total surface fuels, respectively (%RMSE = 37–98%. Fuel metrics were negatively correlated with the severity of tree mortality, except canopy base height, which increased with greater tree mortality. Our results showed how bark beetle-caused tree mortality significantly reduced canopy fuels in our study area. We demonstrated that lidar and Landsat time series data contain substantial information about canopy and surface fuels and can be used for large-scale efforts to monitor and map fuel loads for fire behavior modeling at a landscape scale.

  12. Prediction of forest canopy and surface fuels from Lidar and satellite time series data in a bark beetle-affected forest

    Science.gov (United States)

    Bright, Benjamin C.; Hudak, Andrew T.; Meddens, Arjan J.H.; Hawbaker, Todd J.; Briggs, Jenny S.; Kennedy, Robert E.

    2017-01-01

    Wildfire behavior depends on the type, quantity, and condition of fuels, and the effect that bark beetle outbreaks have on fuels is a topic of current research and debate. Remote sensing can provide estimates of fuels across landscapes, although few studies have estimated surface fuels from remote sensing data. Here we predicted and mapped field-measured canopy and surface fuels from light detection and ranging (lidar) and Landsat time series explanatory variables via random forest (RF) modeling across a coniferous montane forest in Colorado, USA, which was affected by mountain pine beetles (Dendroctonus ponderosae Hopkins) approximately six years prior. We examined relationships between mapped fuels and the severity of tree mortality with correlation tests. RF models explained 59%, 48%, 35%, and 70% of the variation in available canopy fuel, canopy bulk density, canopy base height, and canopy height, respectively (percent root-mean-square error (%RMSE) = 12–54%). Surface fuels were predicted less accurately, with models explaining 24%, 28%, 32%, and 30% of the variation in litter and duff, 1 to 100-h, 1000-h, and total surface fuels, respectively (%RMSE = 37–98%). Fuel metrics were negatively correlated with the severity of tree mortality, except canopy base height, which increased with greater tree mortality. Our results showed how bark beetle-caused tree mortality significantly reduced canopy fuels in our study area. We demonstrated that lidar and Landsat time series data contain substantial information about canopy and surface fuels and can be used for large-scale efforts to monitor and map fuel loads for fire behavior modeling at a landscape scale.

  13. The impact of surface currents and sea level on the wave field evolution during St. Jude storm in the eastern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Marili Viitak

    2016-07-01

    Full Text Available A third generation numerical wave model SWAN (Simulating WAves Nearshore was applied to study the spatio-temporal effect of surface currents and sea level height on significant wave height; and to describe the mechanisms responsible for wave–current interaction in the eastern Baltic Sea. Simulation results were validated by comparison with in situ wave measurements in deep and shallow water, carried out using the directional wave buoy and RDCP respectively, and with TerraSAR-X imagery. A hindcast period from 23 to 31 October 2013 included both a period of calm to moderate weather conditions and a severe North-European windstorm called St. Jude. The prevailing wind directions were southerly to westerly. Four simulations with SWAN were made: a control run with dynamical forcing by wind only; and simulations with additional inputs of surface currents and sea level, both separately and combined. A clear effect of surface currents and sea level on the wave field evolution was found. It manifested itself as an increase or decrease of significant wave height of up to 20%. The strength of the interaction was influenced by the propagation directions of waves and surface currents and the severity of weather conditions. An increase in the wave height was mostly seen in shallower waters and in areas where waves and surface currents were propagating in opposite directions. In deeper parts of the eastern Baltic Sea and in case of waves and surface currents propagating in the same direction a decrease occurred.

  14. Real Time Hybrid Model Predictive Control for the Current Profile of the Tokamak à Configuration Variable (TCV

    Directory of Open Access Journals (Sweden)

    Izaskun Garrido

    2016-08-01

    Full Text Available Plasma stability is one of the obstacles in the path to the successful operation of fusion devices. Numerical control-oriented codes as it is the case of the widely accepted RZIp may be used within Tokamak simulations. The novelty of this article relies in the hierarchical development of a dynamic control loop. It is based on a current profile Model Predictive Control (MPC algorithm within a multiloop structure, where a MPC is developed at each step so as to improve the Proportional Integral Derivative (PID global scheme. The inner control loop is composed of a PID-based controller that acts over the Multiple Input Multiple Output (MIMO system resulting from the RZIp plasma model of the Tokamak à Configuration Variable (TCV. The coefficients of this PID controller are initially tuned using an eigenmode reduction over the passive structure model. The control action corresponding to the state of interest is then optimized in the outer MPC loop. For the sake of comparison, both the traditionally used PID global controller as well as the multiloop enhanced MPC are applied to the same TCV shot. The results show that the proposed control algorithm presents a superior performance over the conventional PID algorithm in terms of convergence. Furthermore, this enhanced MPC algorithm contributes to extend the discharge length and to overcome the limited power availability restrictions that hinder the performance of advanced tokamaks.

  15. A Numerical Simulation for Prediction of Infrared Radiation Emitted from Plain Surfaces with Different Geometries

    Directory of Open Access Journals (Sweden)

    Vakilabadi K.A.

    2017-08-01

    Full Text Available In this paper, infrared radiation exiting plain surfaces with different geometries is numerically simulated. Surfaces under consideration are assumed to have steady uniform heat generation inside. Moreover, the boundaries of the surfaces are considered to be at the surroundings temperature. Infrared radiation is calculated based on the temperature profile determined for the surface. The temperature profile of the surface is determined assuming the two dimensional heat conduction equations to govern the problem. The physical domain is transformed into the appropriate computational domain and the governing equation is mapped into the suitable forms in the new coordinate system of variables. After that the temperature profile of the surface is computed, the infrared radiation distribution of the surface is evaluated based on the equations given in the manuscript. The temperature profile as well as the IR images are given in the results section. It is concluded that the maximum value of infrared radiation of the surface occurs at the center. Moreover, it is concluded that among surfaces with equal areas, the one having the largest perimeter has the least value of IR at its center.

  16. Characterizing AISI 1045 steel surface duplex-treated by alternating current field enhanced pack aluminizing and nitriding

    Science.gov (United States)

    Xie, Fei; Zhang, Ge; Pan, Jianwei

    2018-02-01

    Thin cases and long treating time are shortcomings of conventional duplex treatment of aluminizing followed by nitriding (DTAN). Alternating current field (ACF) enhanced DTAN was carried out on AISI 1045 steel by applying an ACF to treated samples and treating agents with a pair of electrodes for overcoming those shortcomings. By investigating cases' structures, phases, composition and hardness distributions of differently treated samples, preliminary studies were made on characterizations of the ACF enhanced duplex treatment to AISI 1045 steel. The results show that, with the help of the ACF, the surface Al-rich phase Al5Fe2 formed in conventional pack aluminizing can be easily avoided and the aluminizing process is dramatically promoted. The aluminizing case can be nitrided either with conventional pack nitriding or ACF enhanced pack nitriding. By applying ACF to pack nitriding, the diffusion of nitrogen into the aluminizing case is promoted. AlN, Fe2∼3N and solid solution of N in iron are efficiently formed as a result of reactions of N with the aluminizing case. A duplex treated case with an effective thickness of more than 170 μm can be obtained by the alternating current field enhanced 4 h pack aluminizing plus 4 h pack nitriding.

  17. The size prediction of potential inclusions embedded in the sub-surface of fused silica by damage morphology

    Directory of Open Access Journals (Sweden)

    Gao Xiang

    2017-04-01

    Full Text Available A model for predicting the size ranges of different potential inclusions initiating damage on the surface of fused silica has been presented. This accounts for the heating of nanometric inclusions whose absorptivity is described based on Mie Theory. The depth profile of impurities has been measured by ICP-OES. By the measured temporal pulse profile on the surface of fused silica, the temperature and thermal stress has been calculated. Furthermore, considering the limit conditions of temperature and thermal stress strength for different damage morphologies, the size range of potential inclusions for fused silica is discussed.

  18. The size prediction of potential inclusions embedded in the sub-surface of fused silica by damage morphology

    Science.gov (United States)

    Gao, Xiang; Qiu, Rong; Wang, Kunpeng; Zhang, Jiangmei; Zhou, Guorui; Yao, Ke; Jiang, Yong; Zhou, Qiang

    2017-04-01

    A model for predicting the size ranges of different potential inclusions initiating damage on the surface of fused silica has been presented. This accounts for the heating of nanometric inclusions whose absorptivity is described based on Mie Theory. The depth profile of impurities has been measured by ICP-OES. By the measured temporal pulse profile on the surface of fused silica, the temperature and thermal stress has been calculated. Furthermore, considering the limit conditions of temperature and thermal stress strength for different damage morphologies, the size range of potential inclusions for fused silica is discussed.

  19. Seasonal Prediction of Regional Surface Air Temperature and First-flowering Date in South Korea using Dynamical Downscaling

    Science.gov (United States)

    Ahn, J. B.; Hur, J.

    2015-12-01

    The seasonal prediction of both the surface air temperature and the first-flowering date (FFD) over South Korea are produced using dynamical downscaling (Hur and Ahn, 2015). Dynamical downscaling is performed using Weather Research and Forecast (WRF) v3.0 with the lateral forcing from hourly outputs of Pusan National University (PNU) coupled general circulation model (CGCM) v1.1. Gridded surface air temperature data with high spatial (3km) and temporal (daily) resolution are obtained using the physically-based dynamical models. To reduce systematic bias, simple statistical correction method is then applied to the model output. The FFDs of cherry, peach and pear in South Korea are predicted for the decade of 1999-2008 by applying the corrected daily temperature predictions to the phenological thermal-time model. The WRF v3.0 results reflect the detailed topographical effect, despite having cold and warm biases for warm and cold seasons, respectively. After applying the correction, the mean temperature for early spring (February to April) well represents the general pattern of observation, while preserving the advantages of dynamical downscaling. The FFD predictabilities for the three species of trees are evaluated in terms of qualitative, quantitative and categorical estimations. Although FFDs derived from the corrected WRF results well predict the spatial distribution and the variation of observation, the prediction performance has no statistical significance or appropriate predictability. The approach used in the study may be helpful in obtaining detailed and useful information about FFD and regional temperature by accounting for physically-based atmospheric dynamics, although the seasonal predictability of flowering phenology is not high enough. Acknowledgements This work was carried out with the support of the Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009953 and

  20. Linking sardine recruitment in coastal areas to ocean currents using surface drifters and HF radar. A case study in the Gulf of Manfredonia, Adriatic Sea

    DEFF Research Database (Denmark)

    Sciascia, Roberta; Berta, Maristella; Carlson, Daniel Frazier

    2017-01-01

    with observations of surface ocean currents to test two hypotheses: 1) ELHS are transported from remote spawning areas (SAs) by ocean cur- rents to the Gulf of Manfredonia; 2) sardines spawn locally and ELHS are retained by eddies. A historical surface drifter database is used to test hypothesis 1. Hypothesis 2......Understanding the role of ocean currents in the recruitment of commercially and ecologically important fish is an important step towards developing sustainable resource management guidelines. To this end, we attempt to elucidate the role of surface ocean transport in supplying recruits of sardine...... is tested by estimating residence times of surface drifters and virtual particles trajectories that were computed from high resolution observations of surface currents measured by a High Frequency (HF) radar network. Transport from remote SAs seems more likely than local spawning and retention given...

  1. Hourly surface currents measured by high frequency Wellen radars off western Oahu, Hawaii, from September 2002 to May 2003 (NODC Accession 0013113)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A pair of High Frequency Wellen radars (WERA) shore-based at southwest Oahu (Ko'Olina) and northwest Oahu (Kaena), Hawaii measured surface currents over a nine-month...

  2. Hourly surface currents measured by High Frequency (HF) Wellen radars (WERA) off western Oahu, Hawaii, from September 2002 to May 2003 (NODC Accession 0013113)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A pair of High Frequency Wellen radars (WERA) shore-based at southwest Oahu (Ko'Olina) and northwest Oahu (Kaena), Hawaii measured surface currents over a nine-month...

  3. Preliminary investigation into the impacts of assimilating SST and SLA on the surface velocities in a HYCOM of the Agulhas Current

    CSIR Research Space (South Africa)

    Rapeti, T

    2016-10-01

    Full Text Available Data assimilative ocean models play crucial roles in furthering the understanding, and providing forecasts of the Agulhas Current system. This study investigates the impact that assimilating sea surface temperatures (SST) combined with sea level...

  4. Shift in principal equilibrium current from a vertical to a toroidal one towards the initiation of a closed flux surface in ECR plasmas in the LATE device

    Science.gov (United States)

    Kuroda, Kengoh; Wada, Manato; Uchida, Masaki; Tanaka, Hitoshi; Maekawa, Takashi

    2016-02-01

    In toroidal electron cyclotron resonance (ECR) plasmas under a weak external vertical field {{B}\\text{V}} a part of the pressure driven vertical charge separation current returns along the helical field lines, generating a toroidal current. The rest circulates via the conducting vacuum vessel. Only the toroidal current contributes to the production of a closed flux surface. Both the toroidal and vertical currents are an equilibrium current that provides a radial force by the interaction with the vertical field and the toroidal field, respectively, to counter-balance the outward pressure ballooning force. We have done experiments using 2.45 GHz microwaves in the low aspect ratio torus experiment (LATE) device to investigate in what way and how much the toroidal current is generated towards the initiation of a closed flux surface. In steady discharges by {{P}\\text{inj}}=1.5 kW under various {{B}\\text{V}} both the pressure and the toroidal current become large with {{B}\\text{V}} . When {{B}\\text{V}}=6.8 G, a toroidal current of 290 A is generated and the vertical field is reduced to 1.2 G inside the current channel, being close to the initiation of a closed flux surface. In this plasma the return current does not obey Ohm’s law. Instead, the return current flows so that the electric force on the electron fluid is balanced with the pressure gradient along the field lines. Near the top and bottom boundaries superthermal electrons flow beyond the potential barrier onto the walls along the field lines. In another discharge by the low power of {{P}\\text{inj}}=1.0 kW under {{B}\\text{V}}=8.3 G, both the toroidal current and the pressure steadily increase for an initial duration of 1.1 s and then abruptly jump, generating an initial closed flux surface. While the counter force from the vertical current is initially dominant, that from the toroidal current gradually increases and becomes four times larger than that from the vertical current just before the initiation

  5. Surface roughness prediction model in end milling of Al/SiC p MMC ...

    African Journals Online (AJOL)

    This research focuses on study and analyses of surface quality improvement in end milling operation of Al/SiCp metal matrix composite. These materials are selected as they are most widely used in automobile and aerospace industry. This research paper develops an improved mathematical model for surface roughness ...

  6. Predicting internal white oak (Quercus alba) log defect features using surface defect indicator measurements

    Science.gov (United States)

    Ralph E. Thomas

    2012-01-01

    As hardwood trees grow and develop, surface defects such as limb stubs and wounds are overgrown and encapsulated into the tree. Evidence of these defects can remain on the tree's surface for decades and in many instances for the life of the tree. The location and severity of internal defects dictate the quality and value of products that can be obtained from logs...

  7. Surface roughness prediction model in end milling of Al/SiCp MMC ...

    African Journals Online (AJOL)

    user

    Keywords: Surface roughness (Ra), Response surface method (RSM), End milling, Metal matrix composites. DOI: http://dx.doi.org/10.4314/ijest.v3i6.7. 1. Introduction. The recent advancements in the CNC machine tool technology and the wide availability in manufacturing of mechanical components made it possible to ...

  8. Comparative investigation of vibration and current monitoring for prediction of mechanical and electrical faults in induction motor based on multiclass-support vector machine algorithms

    Science.gov (United States)

    Gangsar, Purushottam; Tiwari, Rajiv

    2017-09-01

    This paper presents an investigation of vibration and current monitoring for effective fault prediction in induction motor (IM) by using multiclass support vector machine (MSVM) algorithms. Failures of IM may occur due to propagation of a mechanical or electrical fault. Hence, for timely detection of these faults, the vibration as well as current signals was acquired after multiple experiments of varying speeds and external torques from an experimental test rig. Here, total ten different fault conditions that frequently encountered in IM (four mechanical fault, five electrical fault conditions and one no defect condition) have been considered. In the case of stator winding fault, and phase unbalance and single phasing fault, different level of severity were also considered for the prediction. In this study, the identification has been performed of the mechanical and electrical faults, individually and collectively. Fault predictions have been performed using vibration signal alone, current signal alone and vibration-current signal concurrently. The one-versus-one MSVM has been trained at various operating conditions of IM using the radial basis function (RBF) kernel and tested for same conditions, which gives the result in the form of percentage fault prediction. The prediction performance is investigated for the wide range of RBF kernel parameter, i.e. gamma, and selected the best result for one optimal value of gamma for each case. Fault predictions has been performed and investigated for the wide range of operational speeds of the IM as well as external torques on the IM.

  9. Prediction of strong earthquake motions on rock surface using evolutionary process models

    International Nuclear Information System (INIS)

    Kameda, H.; Sugito, M.

    1984-01-01

    Stochastic process models are developed for prediction of strong earthquake motions for engineering design purposes. Earthquake motions with nonstationary frequency content are modeled by using the concept of evolutionary processes. Discussion is focused on the earthquake motions on bed rocks which are important for construction of nuclear power plants in seismic regions. On this basis, two earthquake motion prediction models are developed, one (EMP-IB Model) for prediction with given magnitude and epicentral distance, and the other (EMP-IIB Model) to account for the successive fault ruptures and the site location relative to the fault of great earthquakes. (Author) [pt

  10. Current status, research needs, and opportunities in applications of surface processing to transportation and utilities technologies. Proceedings of a December 1991 workshop

    Energy Technology Data Exchange (ETDEWEB)

    Czanderna, A.W.; Landgrebe, A.R. [eds.

    1992-09-01

    Goal of surface processing is to develop innovative methods of surface modification and characterization for optimum performance and environmental protection for cost-effective operational lifetimes of systems, materials, and components used in transportation and utilities. These proceedings document the principal discussions and conclusions reached at the workshop; they document chapters about the current status of surface characterization with focus on composition, structure, bonding, and atomic-scale topography of surfaces. Also documented are chapters on the current status of surface modification techniques: electrochemical, plasma-aided, reactive and nonreactive physical vapor deposition, sol-gel coatings, high-energy ion implantation, ion-assisted deposition, organized molecular assemblies, solar energy. Brief chapters in the appendices document basic research in surface science by NSF, Air Force, and DOE. Participants at the workshop were invited to serve on 10 working groups. Separate abstracts were prepared for the data base where appropriate.

  11. Quantitative relationships for the prediction of the vapor pressure of some hydrocarbons from the van der Waals molecular surface

    Directory of Open Access Journals (Sweden)

    Olariu Tudor

    2015-01-01

    Full Text Available A quantitative structure - property relationship (QSPR modeling of vapor pressure at 298.15 K, expressed as log (VP / Pa was performed for a series of 84 hydrocarbons (63 alkanes and 21 cycloalkanes using the van der Waals (vdW surface area, SW/Å2, calculated by the Monte Carlo method, as the molecular descriptor. The QSPR model developed from the subset of 63 alkanes (C1-C16, deemed as the training set, was successfully used for the prediction of the log (VP / Pa values of the 21 cycloalkanes, which was the external prediction (test subset. A QSPR model was also developed for a series composed of all 84 hydrocarbons. Both QSPR models were statistically tested for their ability to fit the data and for prediction. The results showed that the vdW molecular surface used as molecular descriptor (MD explains the variance of the majority of the log (VP / Pa values in this series of 84 hydrocarbons. This MD describes very well the intermolecular forces that hold neutral molecules together. The clear physical meaning of the molecular surface values, SW/Å2, could explain the success of the QSPR models obtained with a single structural molecular descriptor.

  12. Surface potential distribution and airflow performance of different air-exposed electrode plasma actuators at different alternating current/direct current voltages

    International Nuclear Information System (INIS)

    Yang, Liang; Yan, Hui-Jie; Qi, Xiao-Hua; Hua, Yue; Ren, Chun-Sheng

    2015-01-01

    Asymmetric surface dielectric barrier discharge (SDBD) plasma actuators have been intensely studied for a number of years due to their potential applications for aerodynamic control. In this paper, four types of actuators with different configurations of exposed electrode are proposed. The SDBD actuators investigated are driven by dual-power supply, referred to as a fixed AC high voltage and an adjustable DC bias. The effects of the electrode structures on the dielectric surface potential distribution, the electric wind velocity, and the mean thrust production are studied, and the dominative factors of airflow acceleration behavior are revealed. The results have shown that the actions of the SDBD actuator are mainly dependent on the geometry of the exposed electrode. Besides, the surface potential distribution can effectively affect the airflow acceleration behavior. With the application of an appropriate additional DC bias, the surface potential will be modified. As a result, the performance of the electric wind produced by a single SDBD can be significantly improved. In addition, the work also illustrates that the actuators with more negative surface potential present better mechanical performance

  13. Comparative Study on Assimilating Remote Sensing High Frequency Radar Surface Currents at an Atlantic Marine Renewable Energy Test Site

    Directory of Open Access Journals (Sweden)

    Lei Ren

    2017-12-01

    Full Text Available A variety of data assimilation approaches have been applied to enhance modelling capability and accuracy using observations from different sources. The algorithms have varying degrees of complexity of implementation, and they improve model results with varying degrees of success. Very little work has been carried out on comparing the implementation of different data assimilation algorithms using High Frequency radar (HFR data into models of complex inshore waters strongly influenced by both tides and wind dynamics, such as Galway Bay. This research entailed implementing four different data assimilation algorithms: Direct Insertion (DI, Optimal Interpolation (OI, Nudging and indirect data assimilation via correcting model forcing into a three-dimensional hydrodynamic model and carrying out detailed comparisons of model performances. This work will allow researchers to directly compare four of the most common data assimilation algorithms being used in operational coastal hydrodynamics. The suitability of practical data assimilation algorithms for hindcasting and forecasting in shallow coastal waters subjected to alternate wetting and drying using data collected from radars was assessed. Results indicated that a forecasting system of surface currents based on the three-dimensional model EFDC (Environmental Fluid Dynamics Code and the HFR data using a Nudging or DI algorithm was considered the most appropriate for Galway Bay. The largest averaged Data Assimilation Skill Score (DASS over the ≥6 h forecasting period from the best model NDA attained 26% and 31% for east–west and north–south surface velocity components respectively. Because of its ease of implementation and its accuracy, this data assimilation system can provide timely and useful information for various practical coastal hindcast and forecast operations.

  14. Bioclimatic predictions of habitat suitability for the biofuel switchgrass in North America under current and future climate scenarios

    International Nuclear Information System (INIS)

    Barney, Jacob N.; DiTomaso, Joseph M.

    2010-01-01

    Dedicated biofuel crops, while providing economic and other benefits, may adversely impact biodiversity directly via land use conversion, or indirectly via creation of novel invasive species. To mitigate negative impacts bioclimatic envelope models (BEM) can be used to estimate the potential distribution and suitable habitat based on the climate and distribution in the native range. We used CLIMEX to evaluate the regions of North America suitable for agronomic production, as well as regions potentially susceptible to an invasion of switchgrass (Panicum virgatum) under both current and future climate scenarios. Model results show that >8.7 million km 2 of North America has suitable to very favorable habitat, most of which occurs east of the Rocky Mountains. The non-native range of western North America is largely unsuitable to switchgrass as a crop or potential weed unless irrigation or permanent water is available. Under both the CGCM2 and HadCM3 climate models and A2 and B2 emissions scenarios, an overall increase in suitable habitat is predicted over the coming century, although the western US remains unsuitable. Our results suggest that much of North America is suitable for switchgrass cultivation, although this is likely to shift north in the coming century. Our results also agree with field collections of switchgrass outside its native range, which indicate that switchgrass is unlikely to establish unless it has access to water throughout the year (e.g., along a stream). Thus, it is the potential invasion of switchgrass into riparian habitats in the West that requires further investigation. (author)

  15. Prediction of liquid metal alloy radiant properties from measurements of the Hall coefficient and the direct current resistivity

    International Nuclear Information System (INIS)

    Havstad, M.A.; Qiu, T.

    1995-04-01

    The thermal radiative properties of high temperature solid and liquid metal alloys are particularly useful to research and development efforts in laser cladding and machining, electron beam welding and laser isotope separation. However the cost, complexity, and difficulty of measuring these properties have forced the use of crude estimates from the Hagen-Rubens relation, the Drude relations, or extrapolation from low temperature or otherwise flawed data (e.g., oxidized). The authors have found in this work that published values for the Hall coefficient and the electrical resistivity of liquid metal alloys can provide useful estimates of the reflectance and emittance of some groups of binary liquid metal and high temperature solid alloys. The estimation method computes the Drude free electron parameters, and thence the optical constants and the radiant properties from the dependence of the Hall coefficient and direct current resistivity on alloy composition (the Hall coefficient gives the free electron density and the resistivity gives the average time between collisions). They find that predictions of the radiant properties of molten cerium-copper alloy, which use the measured variations in the Hall coefficient and resistivity (both highly nonlinear) as a function of alloy fraction (rather than linear combinations of the values of the pure elements) yield a good comparison to published measurements of the variation of the normal spectral emittance (a different but also nonlinear function) of cerium-copper alloy at the single wavelength available for comparison, 0.645 μm. The success of the approach in the visible range is particularly notable because one expects a Drude based approach to improve with increasing wavelength from the visible into the infrared. Details of the estimation method, the comparison between the calculation and the measured emittance, and a discussion of what groups of elements may also provide agreement is given

  16. Morbidly adherent placenta previa in current practice: prediction and maternal morbidity in a series of 23 women who underwent hysterectomy.

    Science.gov (United States)

    Alchalabi, Haifa'a; L